1 /*
2 This is a version (aka dlmalloc) of malloc/free/realloc written by
3 Doug Lea and released to the public domain, as explained at
4 http://creativecommons.org/licenses/publicdomain. Send questions,
5 comments, complaints, performance data, etc to dl@cs.oswego.edu
6
7 * Version 2.8.3 Thu Sep 22 11:16:15 2005 Doug Lea (dl at gee)
8
9 Note: There may be an updated version of this malloc obtainable at
10 ftp://gee.cs.oswego.edu/pub/misc/malloc.c
11 Check before installing!
12
13 * Quickstart
14
15 This library is all in one file to simplify the most common usage:
16 ftp it, compile it (-O3), and link it into another program. All of
17 the compile-time options default to reasonable values for use on
18 most platforms. You might later want to step through various
19 compile-time and dynamic tuning options.
20
21 For convenience, an include file for code using this malloc is at:
22 ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.3.h
23 You don't really need this .h file unless you call functions not
24 defined in your system include files. The .h file contains only the
25 excerpts from this file needed for using this malloc on ANSI C/C++
26 systems, so long as you haven't changed compile-time options about
27 naming and tuning parameters. If you do, then you can create your
28 own malloc.h that does include all settings by cutting at the point
29 indicated below. Note that you may already by default be using a C
30 library containing a malloc that is based on some version of this
31 malloc (for example in linux). You might still want to use the one
32 in this file to customize settings or to avoid overheads associated
33 with library versions.
34
35 * Vital statistics:
36
37 Supported pointer/size_t representation: 4 or 8 bytes
38 size_t MUST be an unsigned type of the same width as
39 pointers. (If you are using an ancient system that declares
40 size_t as a signed type, or need it to be a different width
41 than pointers, you can use a previous release of this malloc
42 (e.g. 2.7.2) supporting these.)
43
44 Alignment: 8 bytes (default)
45 This suffices for nearly all current machines and C compilers.
46 However, you can define MALLOC_ALIGNMENT to be wider than this
47 if necessary (up to 128bytes), at the expense of using more space.
48
49 Minimum overhead per allocated chunk: 4 or 8 bytes (if 4byte sizes)
50 8 or 16 bytes (if 8byte sizes)
51 Each malloced chunk has a hidden word of overhead holding size
52 and status information, and additional cross-check word
53 if FOOTERS is defined.
54
55 Minimum allocated size: 4-byte ptrs: 16 bytes (including overhead)
56 8-byte ptrs: 32 bytes (including overhead)
57
58 Even a request for zero bytes (i.e., malloc(0)) returns a
59 pointer to something of the minimum allocatable size.
60 The maximum overhead wastage (i.e., number of extra bytes
61 allocated than were requested in malloc) is less than or equal
62 to the minimum size, except for requests >= mmap_threshold that
63 are serviced via mmap(), where the worst case wastage is about
64 32 bytes plus the remainder from a system page (the minimal
65 mmap unit); typically 4096 or 8192 bytes.
66
67 Security: static-safe; optionally more or less
68 The "security" of malloc refers to the ability of malicious
69 code to accentuate the effects of errors (for example, freeing
70 space that is not currently malloc'ed or overwriting past the
71 ends of chunks) in code that calls malloc. This malloc
72 guarantees not to modify any memory locations below the base of
73 heap, i.e., static variables, even in the presence of usage
74 errors. The routines additionally detect most improper frees
75 and reallocs. All this holds as long as the static bookkeeping
76 for malloc itself is not corrupted by some other means. This
77 is only one aspect of security -- these checks do not, and
78 cannot, detect all possible programming errors.
79
80 If FOOTERS is defined nonzero, then each allocated chunk
81 carries an additional check word to verify that it was malloced
82 from its space. These check words are the same within each
83 execution of a program using malloc, but differ across
84 executions, so externally crafted fake chunks cannot be
85 freed. This improves security by rejecting frees/reallocs that
86 could corrupt heap memory, in addition to the checks preventing
87 writes to statics that are always on. This may further improve
88 security at the expense of time and space overhead. (Note that
89 FOOTERS may also be worth using with MSPACES.)
90
91 By default detected errors cause the program to abort (calling
92 "abort()"). You can override this to instead proceed past
93 errors by defining PROCEED_ON_ERROR. In this case, a bad free
94 has no effect, and a malloc that encounters a bad address
95 caused by user overwrites will ignore the bad address by
96 dropping pointers and indices to all known memory. This may
97 be appropriate for programs that should continue if at all
98 possible in the face of programming errors, although they may
99 run out of memory because dropped memory is never reclaimed.
100
101 If you don't like either of these options, you can define
102 CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything
103 else. And if if you are sure that your program using malloc has
104 no errors or vulnerabilities, you can define INSECURE to 1,
105 which might (or might not) provide a small performance improvement.
106
107 Thread-safety: NOT thread-safe unless USE_LOCKS defined
108 When USE_LOCKS is defined, each public call to malloc, free,
109 etc is surrounded with either a pthread mutex or a win32
110 spinlock (depending on WIN32). This is not especially fast, and
111 can be a major bottleneck. It is designed only to provide
112 minimal protection in concurrent environments, and to provide a
113 basis for extensions. If you are using malloc in a concurrent
114 program, consider instead using ptmalloc, which is derived from
115 a version of this malloc. (See http://www.malloc.de).
116
117 System requirements: Any combination of MORECORE and/or MMAP/MUNMAP
118 This malloc can use unix sbrk or any emulation (invoked using
119 the CALL_MORECORE macro) and/or mmap/munmap or any emulation
120 (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system
121 memory. On most unix systems, it tends to work best if both
122 MORECORE and MMAP are enabled. On Win32, it uses emulations
123 based on VirtualAlloc. It also uses common C library functions
124 like memset.
125
126 Compliance: I believe it is compliant with the Single Unix Specification
127 (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably
128 others as well.
129
130 * Overview of algorithms
131
132 This is not the fastest, most space-conserving, most portable, or
133 most tunable malloc ever written. However it is among the fastest
134 while also being among the most space-conserving, portable and
135 tunable. Consistent balance across these factors results in a good
136 general-purpose allocator for malloc-intensive programs.
137
138 In most ways, this malloc is a best-fit allocator. Generally, it
139 chooses the best-fitting existing chunk for a request, with ties
140 broken in approximately least-recently-used order. (This strategy
141 normally maintains low fragmentation.) However, for requests less
142 than 256bytes, it deviates from best-fit when there is not an
143 exactly fitting available chunk by preferring to use space adjacent
144 to that used for the previous small request, as well as by breaking
145 ties in approximately most-recently-used order. (These enhance
146 locality of series of small allocations.) And for very large requests
147 (>= 256Kb by default), it relies on system memory mapping
148 facilities, if supported. (This helps avoid carrying around and
149 possibly fragmenting memory used only for large chunks.)
150
151 All operations (except malloc_stats and mallinfo) have execution
152 times that are bounded by a constant factor of the number of bits in
153 a size_t, not counting any clearing in calloc or copying in realloc,
154 or actions surrounding MORECORE and MMAP that have times
155 proportional to the number of non-contiguous regions returned by
156 system allocation routines, which is often just 1.
157
158 The implementation is not very modular and seriously overuses
159 macros. Perhaps someday all C compilers will do as good a job
160 inlining modular code as can now be done by brute-force expansion,
161 but now, enough of them seem not to.
162
163 Some compilers issue a lot of warnings about code that is
164 dead/unreachable only on some platforms, and also about intentional
165 uses of negation on unsigned types. All known cases of each can be
166 ignored.
167
168 For a longer but out of date high-level description, see
169 http://gee.cs.oswego.edu/dl/html/malloc.html
170
171 * MSPACES
172 If MSPACES is defined, then in addition to malloc, free, etc.,
173 this file also defines mspace_malloc, mspace_free, etc. These
174 are versions of malloc routines that take an "mspace" argument
175 obtained using create_mspace, to control all internal bookkeeping.
176 If ONLY_MSPACES is defined, only these versions are compiled.
177 So if you would like to use this allocator for only some allocations,
178 and your system malloc for others, you can compile with
179 ONLY_MSPACES and then do something like...
180 static mspace mymspace = create_mspace(0,0); // for example
181 #define mymalloc(bytes) mspace_malloc(mymspace, bytes)
182
183 (Note: If you only need one instance of an mspace, you can instead
184 use "USE_DL_PREFIX" to relabel the global malloc.)
185
186 You can similarly create thread-local allocators by storing
187 mspaces as thread-locals. For example:
188 static __thread mspace tlms = 0;
189 void* tlmalloc(size_t bytes) {
190 if (tlms == 0) tlms = create_mspace(0, 0);
191 return mspace_malloc(tlms, bytes);
192 }
193 void tlfree(void* mem) { mspace_free(tlms, mem); }
194
195 Unless FOOTERS is defined, each mspace is completely independent.
196 You cannot allocate from one and free to another (although
197 conformance is only weakly checked, so usage errors are not always
198 caught). If FOOTERS is defined, then each chunk carries around a tag
199 indicating its originating mspace, and frees are directed to their
200 originating spaces.
201
202 ------------------------- Compile-time options ---------------------------
203
204 Be careful in setting #define values for numerical constants of type
205 size_t. On some systems, literal values are not automatically extended
206 to size_t precision unless they are explicitly casted.
207
208 WIN32 default: defined if _WIN32 defined
209 Defining WIN32 sets up defaults for MS environment and compilers.
210 Otherwise defaults are for unix.
211
212 MALLOC_ALIGNMENT default: (size_t)8
213 Controls the minimum alignment for malloc'ed chunks. It must be a
214 power of two and at least 8, even on machines for which smaller
215 alignments would suffice. It may be defined as larger than this
216 though. Note however that code and data structures are optimized for
217 the case of 8-byte alignment.
218
219 MSPACES default: 0 (false)
220 If true, compile in support for independent allocation spaces.
221 This is only supported if HAVE_MMAP is true.
222
223 ONLY_MSPACES default: 0 (false)
224 If true, only compile in mspace versions, not regular versions.
225
226 USE_LOCKS default: 0 (false)
227 Causes each call to each public routine to be surrounded with
228 pthread or WIN32 mutex lock/unlock. (If set true, this can be
229 overridden on a per-mspace basis for mspace versions.)
230
231 FOOTERS default: 0
232 If true, provide extra checking and dispatching by placing
233 information in the footers of allocated chunks. This adds
234 space and time overhead.
235
236 INSECURE default: 0
237 If true, omit checks for usage errors and heap space overwrites.
238
239 USE_DL_PREFIX default: NOT defined
240 Causes compiler to prefix all public routines with the string 'dl'.
241 This can be useful when you only want to use this malloc in one part
242 of a program, using your regular system malloc elsewhere.
243
244 ABORT default: defined as abort()
245 Defines how to abort on failed checks. On most systems, a failed
246 check cannot die with an "assert" or even print an informative
247 message, because the underlying print routines in turn call malloc,
248 which will fail again. Generally, the best policy is to simply call
249 abort(). It's not very useful to do more than this because many
250 errors due to overwriting will show up as address faults (null, odd
251 addresses etc) rather than malloc-triggered checks, so will also
252 abort. Also, most compilers know that abort() does not return, so
253 can better optimize code conditionally calling it.
254
255 PROCEED_ON_ERROR default: defined as 0 (false)
256 Controls whether detected bad addresses cause them to bypassed
257 rather than aborting. If set, detected bad arguments to free and
258 realloc are ignored. And all bookkeeping information is zeroed out
259 upon a detected overwrite of freed heap space, thus losing the
260 ability to ever return it from malloc again, but enabling the
261 application to proceed. If PROCEED_ON_ERROR is defined, the
262 static variable malloc_corruption_error_count is compiled in
263 and can be examined to see if errors have occurred. This option
264 generates slower code than the default abort policy.
265
266 DEBUG default: NOT defined
267 The DEBUG setting is mainly intended for people trying to modify
268 this code or diagnose problems when porting to new platforms.
269 However, it may also be able to better isolate user errors than just
270 using runtime checks. The assertions in the check routines spell
271 out in more detail the assumptions and invariants underlying the
272 algorithms. The checking is fairly extensive, and will slow down
273 execution noticeably. Calling malloc_stats or mallinfo with DEBUG
274 set will attempt to check every non-mmapped allocated and free chunk
275 in the course of computing the summaries.
276
277 ABORT_ON_ASSERT_FAILURE default: defined as 1 (true)
278 Debugging assertion failures can be nearly impossible if your
279 version of the assert macro causes malloc to be called, which will
280 lead to a cascade of further failures, blowing the runtime stack.
281 ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(),
282 which will usually make debugging easier.
283
284 MALLOC_FAILURE_ACTION default: sets errno to ENOMEM, or no-op on win32
285 The action to take before "return 0" when malloc fails to be able to
286 return memory because there is none available.
287
288 HAVE_MORECORE default: 1 (true) unless win32 or ONLY_MSPACES
289 True if this system supports sbrk or an emulation of it.
290
291 MORECORE default: sbrk
292 The name of the sbrk-style system routine to call to obtain more
293 memory. See below for guidance on writing custom MORECORE
294 functions. The type of the argument to sbrk/MORECORE varies across
295 systems. It cannot be size_t, because it supports negative
296 arguments, so it is normally the signed type of the same width as
297 size_t (sometimes declared as "intptr_t"). It doesn't much matter
298 though. Internally, we only call it with arguments less than half
299 the max value of a size_t, which should work across all reasonable
300 possibilities, although sometimes generating compiler warnings. See
301 near the end of this file for guidelines for creating a custom
302 version of MORECORE.
303
304 MORECORE_CONTIGUOUS default: 1 (true)
305 If true, take advantage of fact that consecutive calls to MORECORE
306 with positive arguments always return contiguous increasing
307 addresses. This is true of unix sbrk. It does not hurt too much to
308 set it true anyway, since malloc copes with non-contiguities.
309 Setting it false when definitely non-contiguous saves time
310 and possibly wasted space it would take to discover this though.
311
312 MORECORE_CANNOT_TRIM default: NOT defined
313 True if MORECORE cannot release space back to the system when given
314 negative arguments. This is generally necessary only if you are
315 using a hand-crafted MORECORE function that cannot handle negative
316 arguments.
317
318 HAVE_MMAP default: 1 (true)
319 True if this system supports mmap or an emulation of it. If so, and
320 HAVE_MORECORE is not true, MMAP is used for all system
321 allocation. If set and HAVE_MORECORE is true as well, MMAP is
322 primarily used to directly allocate very large blocks. It is also
323 used as a backup strategy in cases where MORECORE fails to provide
324 space from system. Note: A single call to MUNMAP is assumed to be
325 able to unmap memory that may have be allocated using multiple calls
326 to MMAP, so long as they are adjacent.
327
328 HAVE_MREMAP default: 1 on linux, else 0
329 If true realloc() uses mremap() to re-allocate large blocks and
330 extend or shrink allocation spaces.
331
332 MMAP_CLEARS default: 1 on unix
333 True if mmap clears memory so calloc doesn't need to. This is true
334 for standard unix mmap using /dev/zero.
335
336 USE_BUILTIN_FFS default: 0 (i.e., not used)
337 Causes malloc to use the builtin ffs() function to compute indices.
338 Some compilers may recognize and intrinsify ffs to be faster than the
339 supplied C version. Also, the case of x86 using gcc is special-cased
340 to an asm instruction, so is already as fast as it can be, and so
341 this setting has no effect. (On most x86s, the asm version is only
342 slightly faster than the C version.)
343
344 malloc_getpagesize default: derive from system includes, or 4096.
345 The system page size. To the extent possible, this malloc manages
346 memory from the system in page-size units. This may be (and
347 usually is) a function rather than a constant. This is ignored
348 if WIN32, where page size is determined using getSystemInfo during
349 initialization.
350
351 USE_DEV_RANDOM default: 0 (i.e., not used)
352 Causes malloc to use /dev/random to initialize secure magic seed for
353 stamping footers. Otherwise, the current time is used.
354
355 NO_MALLINFO default: 0
356 If defined, don't compile "mallinfo". This can be a simple way
357 of dealing with mismatches between system declarations and
358 those in this file.
359
360 MALLINFO_FIELD_TYPE default: size_t
361 The type of the fields in the mallinfo struct. This was originally
362 defined as "int" in SVID etc, but is more usefully defined as
363 size_t. The value is used only if HAVE_USR_INCLUDE_MALLOC_H is not set
364
365 REALLOC_ZERO_BYTES_FREES default: not defined
366 This should be set if a call to realloc with zero bytes should
367 be the same as a call to free. Some people think it should. Otherwise,
368 since this malloc returns a unique pointer for malloc(0), so does
369 realloc(p, 0).
370
371 LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H
372 LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H, LACKS_ERRNO_H
373 LACKS_STDLIB_H default: NOT defined unless on WIN32
374 Define these if your system does not have these header files.
375 You might need to manually insert some of the declarations they provide.
376
377 DEFAULT_GRANULARITY default: page size if MORECORE_CONTIGUOUS,
378 system_info.dwAllocationGranularity in WIN32,
379 otherwise 64K.
380 Also settable using mallopt(M_GRANULARITY, x)
381 The unit for allocating and deallocating memory from the system. On
382 most systems with contiguous MORECORE, there is no reason to
383 make this more than a page. However, systems with MMAP tend to
384 either require or encourage larger granularities. You can increase
385 this value to prevent system allocation functions to be called so
386 often, especially if they are slow. The value must be at least one
387 page and must be a power of two. Setting to 0 causes initialization
388 to either page size or win32 region size. (Note: In previous
389 versions of malloc, the equivalent of this option was called
390 "TOP_PAD")
391
392 DEFAULT_TRIM_THRESHOLD default: 2MB
393 Also settable using mallopt(M_TRIM_THRESHOLD, x)
394 The maximum amount of unused top-most memory to keep before
395 releasing via malloc_trim in free(). Automatic trimming is mainly
396 useful in long-lived programs using contiguous MORECORE. Because
397 trimming via sbrk can be slow on some systems, and can sometimes be
398 wasteful (in cases where programs immediately afterward allocate
399 more large chunks) the value should be high enough so that your
400 overall system performance would improve by releasing this much
401 memory. As a rough guide, you might set to a value close to the
402 average size of a process (program) running on your system.
403 Releasing this much memory would allow such a process to run in
404 memory. Generally, it is worth tuning trim thresholds when a
405 program undergoes phases where several large chunks are allocated
406 and released in ways that can reuse each other's storage, perhaps
407 mixed with phases where there are no such chunks at all. The trim
408 value must be greater than page size to have any useful effect. To
409 disable trimming completely, you can set to MAX_SIZE_T. Note that the trick
410 some people use of mallocing a huge space and then freeing it at
411 program startup, in an attempt to reserve system memory, doesn't
412 have the intended effect under automatic trimming, since that memory
413 will immediately be returned to the system.
414
415 DEFAULT_MMAP_THRESHOLD default: 256K
416 Also settable using mallopt(M_MMAP_THRESHOLD, x)
417 The request size threshold for using MMAP to directly service a
418 request. Requests of at least this size that cannot be allocated
419 using already-existing space will be serviced via mmap. (If enough
420 normal freed space already exists it is used instead.) Using mmap
421 segregates relatively large chunks of memory so that they can be
422 individually obtained and released from the host system. A request
423 serviced through mmap is never reused by any other request (at least
424 not directly; the system may just so happen to remap successive
425 requests to the same locations). Segregating space in this way has
426 the benefits that: Mmapped space can always be individually released
427 back to the system, which helps keep the system level memory demands
428 of a long-lived program low. Also, mapped memory doesn't become
429 `locked' between other chunks, as can happen with normally allocated
430 chunks, which means that even trimming via malloc_trim would not
431 release them. However, it has the disadvantage that the space
432 cannot be reclaimed, consolidated, and then used to service later
433 requests, as happens with normal chunks. The advantages of mmap
434 nearly always outweigh disadvantages for "large" chunks, but the
435 value of "large" may vary across systems. The default is an
436 empirically derived value that works well in most systems. You can
437 disable mmap by setting to MAX_SIZE_T.
438
439 */
440
441 #if defined __linux__ && !defined _GNU_SOURCE
442 /* mremap() on Linux requires this via sys/mman.h */
443 #define _GNU_SOURCE 1
444 #endif
445
446 #ifndef WIN32
447 #ifdef _WIN32
448 #define WIN32 1
449 #endif /* _WIN32 */
450 #endif /* WIN32 */
451 #ifdef WIN32
452 #define WIN32_LEAN_AND_MEAN
453 #include <windows.h>
454 #define HAVE_MMAP 1
455 #define HAVE_MORECORE 0
456 #define LACKS_UNISTD_H
457 #define LACKS_SYS_PARAM_H
458 #define LACKS_SYS_MMAN_H
459 #define LACKS_STRING_H
460 #define LACKS_STRINGS_H
461 #define LACKS_SYS_TYPES_H
462 #define LACKS_ERRNO_H
463 #define MALLOC_FAILURE_ACTION
464 #define MMAP_CLEARS 0 /* WINCE and some others apparently don't clear */
465 #endif /* WIN32 */
466
467 #ifdef __OS2__
468 #define INCL_DOS
469 #include <os2.h>
470 #define HAVE_MMAP 1
471 #define HAVE_MORECORE 0
472 #define LACKS_SYS_MMAN_H
473 #endif /* __OS2__ */
474
475 #if defined(DARWIN) || defined(_DARWIN)
476 /* Mac OSX docs advise not to use sbrk; it seems better to use mmap */
477 #ifndef HAVE_MORECORE
478 #define HAVE_MORECORE 0
479 #define HAVE_MMAP 1
480 #endif /* HAVE_MORECORE */
481 #endif /* DARWIN */
482
483 #ifndef LACKS_SYS_TYPES_H
484 #include <sys/types.h> /* For size_t */
485 #endif /* LACKS_SYS_TYPES_H */
486
487 /* The maximum possible size_t value has all bits set */
488 #define MAX_SIZE_T (~(size_t)0)
489
490 #ifndef ONLY_MSPACES
491 #define ONLY_MSPACES 0
492 #endif /* ONLY_MSPACES */
493 #ifndef MSPACES
494 #if ONLY_MSPACES
495 #define MSPACES 1
496 #else /* ONLY_MSPACES */
497 #define MSPACES 0
498 #endif /* ONLY_MSPACES */
499 #endif /* MSPACES */
500 #ifndef MALLOC_ALIGNMENT
501 #define MALLOC_ALIGNMENT ((size_t)8U)
502 #endif /* MALLOC_ALIGNMENT */
503 #ifndef FOOTERS
504 #define FOOTERS 0
505 #endif /* FOOTERS */
506 #ifndef ABORT
507 #define ABORT abort()
508 #endif /* ABORT */
509 #ifndef ABORT_ON_ASSERT_FAILURE
510 #define ABORT_ON_ASSERT_FAILURE 1
511 #endif /* ABORT_ON_ASSERT_FAILURE */
512 #ifndef PROCEED_ON_ERROR
513 #define PROCEED_ON_ERROR 0
514 #endif /* PROCEED_ON_ERROR */
515 #ifndef USE_LOCKS
516 #define USE_LOCKS 0
517 #endif /* USE_LOCKS */
518 #ifndef INSECURE
519 #define INSECURE 0
520 #endif /* INSECURE */
521 #ifndef HAVE_MMAP
522 #define HAVE_MMAP 1
523 #endif /* HAVE_MMAP */
524 #ifndef MMAP_CLEARS
525 #define MMAP_CLEARS 1
526 #endif /* MMAP_CLEARS */
527 #ifndef HAVE_MREMAP
528 #ifdef linux
529 #define HAVE_MREMAP 1
530 #else /* linux */
531 #define HAVE_MREMAP 0
532 #endif /* linux */
533 #endif /* HAVE_MREMAP */
534 #ifndef MALLOC_FAILURE_ACTION
535 #define MALLOC_FAILURE_ACTION errno = ENOMEM;
536 #endif /* MALLOC_FAILURE_ACTION */
537 #ifndef HAVE_MORECORE
538 #if ONLY_MSPACES
539 #define HAVE_MORECORE 0
540 #else /* ONLY_MSPACES */
541 #define HAVE_MORECORE 1
542 #endif /* ONLY_MSPACES */
543 #endif /* HAVE_MORECORE */
544 #if !HAVE_MORECORE
545 #define MORECORE_CONTIGUOUS 0
546 #else /* !HAVE_MORECORE */
547 #ifndef MORECORE
548 #define MORECORE sbrk
549 #endif /* MORECORE */
550 #ifndef MORECORE_CONTIGUOUS
551 #define MORECORE_CONTIGUOUS 1
552 #endif /* MORECORE_CONTIGUOUS */
553 #endif /* HAVE_MORECORE */
554 #ifndef DEFAULT_GRANULARITY
555 #if MORECORE_CONTIGUOUS
556 #define DEFAULT_GRANULARITY (0) /* 0 means to compute in init_mparams */
557 #else /* MORECORE_CONTIGUOUS */
558 #define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U)
559 #endif /* MORECORE_CONTIGUOUS */
560 #endif /* DEFAULT_GRANULARITY */
561 #ifndef DEFAULT_TRIM_THRESHOLD
562 #ifndef MORECORE_CANNOT_TRIM
563 #define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U)
564 #else /* MORECORE_CANNOT_TRIM */
565 #define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T
566 #endif /* MORECORE_CANNOT_TRIM */
567 #endif /* DEFAULT_TRIM_THRESHOLD */
568 #ifndef DEFAULT_MMAP_THRESHOLD
569 #if HAVE_MMAP
570 #define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U)
571 #else /* HAVE_MMAP */
572 #define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T
573 #endif /* HAVE_MMAP */
574 #endif /* DEFAULT_MMAP_THRESHOLD */
575 #ifndef USE_BUILTIN_FFS
576 #define USE_BUILTIN_FFS 0
577 #endif /* USE_BUILTIN_FFS */
578 #ifndef USE_DEV_RANDOM
579 #define USE_DEV_RANDOM 0
580 #endif /* USE_DEV_RANDOM */
581 #ifndef NO_MALLINFO
582 #define NO_MALLINFO 0
583 #endif /* NO_MALLINFO */
584 #ifndef MALLINFO_FIELD_TYPE
585 #define MALLINFO_FIELD_TYPE size_t
586 #endif /* MALLINFO_FIELD_TYPE */
587
588 /*
589 mallopt tuning options. SVID/XPG defines four standard parameter
590 numbers for mallopt, normally defined in malloc.h. None of these
591 are used in this malloc, so setting them has no effect. But this
592 malloc does support the following options.
593 */
594
595 #define M_TRIM_THRESHOLD (-1)
596 #define M_GRANULARITY (-2)
597 #define M_MMAP_THRESHOLD (-3)
598
599 /* ------------------------ Mallinfo declarations ------------------------ */
600
601 #if !NO_MALLINFO
602 /*
603 This version of malloc supports the standard SVID/XPG mallinfo
604 routine that returns a struct containing usage properties and
605 statistics. It should work on any system that has a
606 /usr/include/malloc.h defining struct mallinfo. The main
607 declaration needed is the mallinfo struct that is returned (by-copy)
608 by mallinfo(). The malloinfo struct contains a bunch of fields that
609 are not even meaningful in this version of malloc. These fields are
610 are instead filled by mallinfo() with other numbers that might be of
611 interest.
612
613 HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
614 /usr/include/malloc.h file that includes a declaration of struct
615 mallinfo. If so, it is included; else a compliant version is
616 declared below. These must be precisely the same for mallinfo() to
617 work. The original SVID version of this struct, defined on most
618 systems with mallinfo, declares all fields as ints. But some others
619 define as unsigned long. If your system defines the fields using a
620 type of different width than listed here, you MUST #include your
621 system version and #define HAVE_USR_INCLUDE_MALLOC_H.
622 */
623
624 /* #define HAVE_USR_INCLUDE_MALLOC_H */
625
626 #ifdef HAVE_USR_INCLUDE_MALLOC_H
627 #include "/usr/include/malloc.h"
628 #else /* HAVE_USR_INCLUDE_MALLOC_H */
629
630 /* HP-UX's stdlib.h redefines mallinfo unless _STRUCT_MALLINFO is defined */
631 #define _STRUCT_MALLINFO
632
633 struct mallinfo {
634 MALLINFO_FIELD_TYPE arena; /* non-mmapped space allocated from system */
635 MALLINFO_FIELD_TYPE ordblks; /* number of free chunks */
636 MALLINFO_FIELD_TYPE smblks; /* always 0 */
637 MALLINFO_FIELD_TYPE hblks; /* always 0 */
638 MALLINFO_FIELD_TYPE hblkhd; /* space in mmapped regions */
639 MALLINFO_FIELD_TYPE usmblks; /* maximum total allocated space */
640 MALLINFO_FIELD_TYPE fsmblks; /* always 0 */
641 MALLINFO_FIELD_TYPE uordblks; /* total allocated space */
642 MALLINFO_FIELD_TYPE fordblks; /* total free space */
643 MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */
644 };
645
646 #endif /* HAVE_USR_INCLUDE_MALLOC_H */
647 #endif /* NO_MALLINFO */
648
649 #ifdef __cplusplus
650 extern "C" {
651 #endif /* __cplusplus */
652
653 #if !ONLY_MSPACES
654
655 /* ------------------- Declarations of public routines ------------------- */
656
657 #ifndef USE_DL_PREFIX
658 #define dlcalloc calloc
659 #define dlfree free
660 #define dlmalloc malloc
661 #define dlmemalign memalign
662 #define dlrealloc realloc
663 #define dlvalloc valloc
664 #define dlpvalloc pvalloc
665 #define dlmallinfo mallinfo
666 #define dlmallopt mallopt
667 #define dlmalloc_trim malloc_trim
668 #define dlmalloc_stats malloc_stats
669 #define dlmalloc_usable_size malloc_usable_size
670 #define dlmalloc_footprint malloc_footprint
671 #define dlmalloc_max_footprint malloc_max_footprint
672 #define dlindependent_calloc independent_calloc
673 #define dlindependent_comalloc independent_comalloc
674 #endif /* USE_DL_PREFIX */
675
676
677 /*
678 malloc(size_t n)
679 Returns a pointer to a newly allocated chunk of at least n bytes, or
680 null if no space is available, in which case errno is set to ENOMEM
681 on ANSI C systems.
682
683 If n is zero, malloc returns a minimum-sized chunk. (The minimum
684 size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
685 systems.) Note that size_t is an unsigned type, so calls with
686 arguments that would be negative if signed are interpreted as
687 requests for huge amounts of space, which will often fail. The
688 maximum supported value of n differs across systems, but is in all
689 cases less than the maximum representable value of a size_t.
690 */
691 void* dlmalloc(size_t);
692
693 /*
694 free(void* p)
695 Releases the chunk of memory pointed to by p, that had been previously
696 allocated using malloc or a related routine such as realloc.
697 It has no effect if p is null. If p was not malloced or already
698 freed, free(p) will by default cause the current program to abort.
699 */
700 void dlfree(void*);
701
702 /*
703 calloc(size_t n_elements, size_t element_size);
704 Returns a pointer to n_elements * element_size bytes, with all locations
705 set to zero.
706 */
707 void* dlcalloc(size_t, size_t);
708
709 /*
710 realloc(void* p, size_t n)
711 Returns a pointer to a chunk of size n that contains the same data
712 as does chunk p up to the minimum of (n, p's size) bytes, or null
713 if no space is available.
714
715 The returned pointer may or may not be the same as p. The algorithm
716 prefers extending p in most cases when possible, otherwise it
717 employs the equivalent of a malloc-copy-free sequence.
718
719 If p is null, realloc is equivalent to malloc.
720
721 If space is not available, realloc returns null, errno is set (if on
722 ANSI) and p is NOT freed.
723
724 if n is for fewer bytes than already held by p, the newly unused
725 space is lopped off and freed if possible. realloc with a size
726 argument of zero (re)allocates a minimum-sized chunk.
727
728 The old unix realloc convention of allowing the last-free'd chunk
729 to be used as an argument to realloc is not supported.
730 */
731
732 void* dlrealloc(void*, size_t);
733
734 /*
735 memalign(size_t alignment, size_t n);
736 Returns a pointer to a newly allocated chunk of n bytes, aligned
737 in accord with the alignment argument.
738
739 The alignment argument should be a power of two. If the argument is
740 not a power of two, the nearest greater power is used.
741 8-byte alignment is guaranteed by normal malloc calls, so don't
742 bother calling memalign with an argument of 8 or less.
743
744 Overreliance on memalign is a sure way to fragment space.
745 */
746 void* dlmemalign(size_t, size_t);
747
748 /*
749 valloc(size_t n);
750 Equivalent to memalign(pagesize, n), where pagesize is the page
751 size of the system. If the pagesize is unknown, 4096 is used.
752 */
753 void* dlvalloc(size_t);
754
755 /*
756 mallopt(int parameter_number, int parameter_value)
757 Sets tunable parameters The format is to provide a
758 (parameter-number, parameter-value) pair. mallopt then sets the
759 corresponding parameter to the argument value if it can (i.e., so
760 long as the value is meaningful), and returns 1 if successful else
761 0. SVID/XPG/ANSI defines four standard param numbers for mallopt,
762 normally defined in malloc.h. None of these are use in this malloc,
763 so setting them has no effect. But this malloc also supports other
764 options in mallopt. See below for details. Briefly, supported
765 parameters are as follows (listed defaults are for "typical"
766 configurations).
767
768 Symbol param # default allowed param values
769 M_TRIM_THRESHOLD -1 2*1024*1024 any (MAX_SIZE_T disables)
770 M_GRANULARITY -2 page size any power of 2 >= page size
771 M_MMAP_THRESHOLD -3 256*1024 any (or 0 if no MMAP support)
772 */
773 int dlmallopt(int, int);
774
775 /*
776 malloc_footprint();
777 Returns the number of bytes obtained from the system. The total
778 number of bytes allocated by malloc, realloc etc., is less than this
779 value. Unlike mallinfo, this function returns only a precomputed
780 result, so can be called frequently to monitor memory consumption.
781 Even if locks are otherwise defined, this function does not use them,
782 so results might not be up to date.
783 */
784 size_t dlmalloc_footprint(void);
785
786 /*
787 malloc_max_footprint();
788 Returns the maximum number of bytes obtained from the system. This
789 value will be greater than current footprint if deallocated space
790 has been reclaimed by the system. The peak number of bytes allocated
791 by malloc, realloc etc., is less than this value. Unlike mallinfo,
792 this function returns only a precomputed result, so can be called
793 frequently to monitor memory consumption. Even if locks are
794 otherwise defined, this function does not use them, so results might
795 not be up to date.
796 */
797 size_t dlmalloc_max_footprint(void);
798
799 #if !NO_MALLINFO
800 /*
801 mallinfo()
802 Returns (by copy) a struct containing various summary statistics:
803
804 arena: current total non-mmapped bytes allocated from system
805 ordblks: the number of free chunks
806 smblks: always zero.
807 hblks: current number of mmapped regions
808 hblkhd: total bytes held in mmapped regions
809 usmblks: the maximum total allocated space. This will be greater
810 than current total if trimming has occurred.
811 fsmblks: always zero
812 uordblks: current total allocated space (normal or mmapped)
813 fordblks: total free space
814 keepcost: the maximum number of bytes that could ideally be released
815 back to system via malloc_trim. ("ideally" means that
816 it ignores page restrictions etc.)
817
818 Because these fields are ints, but internal bookkeeping may
819 be kept as longs, the reported values may wrap around zero and
820 thus be inaccurate.
821 */
822 struct mallinfo dlmallinfo(void);
823 #endif /* NO_MALLINFO */
824
825 /*
826 independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
827
828 independent_calloc is similar to calloc, but instead of returning a
829 single cleared space, it returns an array of pointers to n_elements
830 independent elements that can hold contents of size elem_size, each
831 of which starts out cleared, and can be independently freed,
832 realloc'ed etc. The elements are guaranteed to be adjacently
833 allocated (this is not guaranteed to occur with multiple callocs or
834 mallocs), which may also improve cache locality in some
835 applications.
836
837 The "chunks" argument is optional (i.e., may be null, which is
838 probably the most typical usage). If it is null, the returned array
839 is itself dynamically allocated and should also be freed when it is
840 no longer needed. Otherwise, the chunks array must be of at least
841 n_elements in length. It is filled in with the pointers to the
842 chunks.
843
844 In either case, independent_calloc returns this pointer array, or
845 null if the allocation failed. If n_elements is zero and "chunks"
846 is null, it returns a chunk representing an array with zero elements
847 (which should be freed if not wanted).
848
849 Each element must be individually freed when it is no longer
850 needed. If you'd like to instead be able to free all at once, you
851 should instead use regular calloc and assign pointers into this
852 space to represent elements. (In this case though, you cannot
853 independently free elements.)
854
855 independent_calloc simplifies and speeds up implementations of many
856 kinds of pools. It may also be useful when constructing large data
857 structures that initially have a fixed number of fixed-sized nodes,
858 but the number is not known at compile time, and some of the nodes
859 may later need to be freed. For example:
860
861 struct Node { int item; struct Node* next; };
862
863 struct Node* build_list() {
864 struct Node** pool;
865 int n = read_number_of_nodes_needed();
866 if (n <= 0) return 0;
867 pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
868 if (pool == 0) die();
869 // organize into a linked list...
870 struct Node* first = pool[0];
871 for (i = 0; i < n-1; ++i)
872 pool[i]->next = pool[i+1];
873 free(pool); // Can now free the array (or not, if it is needed later)
874 return first;
875 }
876 */
877 void** dlindependent_calloc(size_t, size_t, void**);
878
879 /*
880 independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
881
882 independent_comalloc allocates, all at once, a set of n_elements
883 chunks with sizes indicated in the "sizes" array. It returns
884 an array of pointers to these elements, each of which can be
885 independently freed, realloc'ed etc. The elements are guaranteed to
886 be adjacently allocated (this is not guaranteed to occur with
887 multiple callocs or mallocs), which may also improve cache locality
888 in some applications.
889
890 The "chunks" argument is optional (i.e., may be null). If it is null
891 the returned array is itself dynamically allocated and should also
892 be freed when it is no longer needed. Otherwise, the chunks array
893 must be of at least n_elements in length. It is filled in with the
894 pointers to the chunks.
895
896 In either case, independent_comalloc returns this pointer array, or
897 null if the allocation failed. If n_elements is zero and chunks is
898 null, it returns a chunk representing an array with zero elements
899 (which should be freed if not wanted).
900
901 Each element must be individually freed when it is no longer
902 needed. If you'd like to instead be able to free all at once, you
903 should instead use a single regular malloc, and assign pointers at
904 particular offsets in the aggregate space. (In this case though, you
905 cannot independently free elements.)
906
907 independent_comallac differs from independent_calloc in that each
908 element may have a different size, and also that it does not
909 automatically clear elements.
910
911 independent_comalloc can be used to speed up allocation in cases
912 where several structs or objects must always be allocated at the
913 same time. For example:
914
915 struct Head { ... }
916 struct Foot { ... }
917
918 void send_message(char* msg) {
919 int msglen = strlen(msg);
920 size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
921 void* chunks[3];
922 if (independent_comalloc(3, sizes, chunks) == 0)
923 die();
924 struct Head* head = (struct Head*)(chunks[0]);
925 char* body = (char*)(chunks[1]);
926 struct Foot* foot = (struct Foot*)(chunks[2]);
927 // ...
928 }
929
930 In general though, independent_comalloc is worth using only for
931 larger values of n_elements. For small values, you probably won't
932 detect enough difference from series of malloc calls to bother.
933
934 Overuse of independent_comalloc can increase overall memory usage,
935 since it cannot reuse existing noncontiguous small chunks that
936 might be available for some of the elements.
937 */
938 void** dlindependent_comalloc(size_t, size_t*, void**);
939
940
941 /*
942 pvalloc(size_t n);
943 Equivalent to valloc(minimum-page-that-holds(n)), that is,
944 round up n to nearest pagesize.
945 */
946 void* dlpvalloc(size_t);
947
948 /*
949 malloc_trim(size_t pad);
950
951 If possible, gives memory back to the system (via negative arguments
952 to sbrk) if there is unused memory at the `high' end of the malloc
953 pool or in unused MMAP segments. You can call this after freeing
954 large blocks of memory to potentially reduce the system-level memory
955 requirements of a program. However, it cannot guarantee to reduce
956 memory. Under some allocation patterns, some large free blocks of
957 memory will be locked between two used chunks, so they cannot be
958 given back to the system.
959
960 The `pad' argument to malloc_trim represents the amount of free
961 trailing space to leave untrimmed. If this argument is zero, only
962 the minimum amount of memory to maintain internal data structures
963 will be left. Non-zero arguments can be supplied to maintain enough
964 trailing space to service future expected allocations without having
965 to re-obtain memory from the system.
966
967 Malloc_trim returns 1 if it actually released any memory, else 0.
968 */
969 int dlmalloc_trim(size_t);
970
971 /*
972 malloc_usable_size(void* p);
973
974 Returns the number of bytes you can actually use in
975 an allocated chunk, which may be more than you requested (although
976 often not) due to alignment and minimum size constraints.
977 You can use this many bytes without worrying about
978 overwriting other allocated objects. This is not a particularly great
979 programming practice. malloc_usable_size can be more useful in
980 debugging and assertions, for example:
981
982 p = malloc(n);
983 assert(malloc_usable_size(p) >= 256);
984 */
985 size_t dlmalloc_usable_size(void*);
986
987 /*
988 malloc_stats();
989 Prints on stderr the amount of space obtained from the system (both
990 via sbrk and mmap), the maximum amount (which may be more than
991 current if malloc_trim and/or munmap got called), and the current
992 number of bytes allocated via malloc (or realloc, etc) but not yet
993 freed. Note that this is the number of bytes allocated, not the
994 number requested. It will be larger than the number requested
995 because of alignment and bookkeeping overhead. Because it includes
996 alignment wastage as being in use, this figure may be greater than
997 zero even when no user-level chunks are allocated.
998
999 The reported current and maximum system memory can be inaccurate if
1000 a program makes other calls to system memory allocation functions
1001 (normally sbrk) outside of malloc.
1002
1003 malloc_stats prints only the most commonly interesting statistics.
1004 More information can be obtained by calling mallinfo.
1005 */
1006 void dlmalloc_stats(void);
1007
1008 #endif /* ONLY_MSPACES */
1009
1010 #if MSPACES
1011
1012 /*
1013 mspace is an opaque type representing an independent
1014 region of space that supports mspace_malloc, etc.
1015 */
1016 typedef void* mspace;
1017
1018 /*
1019 create_mspace creates and returns a new independent space with the
1020 given initial capacity, or, if 0, the default granularity size. It
1021 returns null if there is no system memory available to create the
1022 space. If argument locked is non-zero, the space uses a separate
1023 lock to control access. The capacity of the space will grow
1024 dynamically as needed to service mspace_malloc requests. You can
1025 control the sizes of incremental increases of this space by
1026 compiling with a different DEFAULT_GRANULARITY or dynamically
1027 setting with mallopt(M_GRANULARITY, value).
1028 */
1029 mspace create_mspace(size_t capacity, int locked);
1030
1031 /*
1032 destroy_mspace destroys the given space, and attempts to return all
1033 of its memory back to the system, returning the total number of
1034 bytes freed. After destruction, the results of access to all memory
1035 used by the space become undefined.
1036 */
1037 size_t destroy_mspace(mspace msp);
1038
1039 /*
1040 create_mspace_with_base uses the memory supplied as the initial base
1041 of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
1042 space is used for bookkeeping, so the capacity must be at least this
1043 large. (Otherwise 0 is returned.) When this initial space is
1044 exhausted, additional memory will be obtained from the system.
1045 Destroying this space will deallocate all additionally allocated
1046 space (if possible) but not the initial base.
1047 */
1048 mspace create_mspace_with_base(void* base, size_t capacity, int locked);
1049
1050 /*
1051 mspace_malloc behaves as malloc, but operates within
1052 the given space.
1053 */
1054 void* mspace_malloc(mspace msp, size_t bytes);
1055
1056 /*
1057 mspace_free behaves as free, but operates within
1058 the given space.
1059
1060 If compiled with FOOTERS==1, mspace_free is not actually needed.
1061 free may be called instead of mspace_free because freed chunks from
1062 any space are handled by their originating spaces.
1063 */
1064 void mspace_free(mspace msp, void* mem);
1065
1066 /*
1067 mspace_realloc behaves as realloc, but operates within
1068 the given space.
1069
1070 If compiled with FOOTERS==1, mspace_realloc is not actually
1071 needed. realloc may be called instead of mspace_realloc because
1072 realloced chunks from any space are handled by their originating
1073 spaces.
1074 */
1075 void* mspace_realloc(mspace msp, void* mem, size_t newsize);
1076
1077 /*
1078 mspace_calloc behaves as calloc, but operates within
1079 the given space.
1080 */
1081 void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
1082
1083 /*
1084 mspace_memalign behaves as memalign, but operates within
1085 the given space.
1086 */
1087 void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);
1088
1089 /*
1090 mspace_independent_calloc behaves as independent_calloc, but
1091 operates within the given space.
1092 */
1093 void** mspace_independent_calloc(mspace msp, size_t n_elements,
1094 size_t elem_size, void* chunks[]);
1095
1096 /*
1097 mspace_independent_comalloc behaves as independent_comalloc, but
1098 operates within the given space.
1099 */
1100 void** mspace_independent_comalloc(mspace msp, size_t n_elements,
1101 size_t sizes[], void* chunks[]);
1102
1103 /*
1104 mspace_footprint() returns the number of bytes obtained from the
1105 system for this space.
1106 */
1107 size_t mspace_footprint(mspace msp);
1108
1109 /*
1110 mspace_max_footprint() returns the peak number of bytes obtained from the
1111 system for this space.
1112 */
1113 size_t mspace_max_footprint(mspace msp);
1114
1115
1116 #if !NO_MALLINFO
1117 /*
1118 mspace_mallinfo behaves as mallinfo, but reports properties of
1119 the given space.
1120 */
1121 struct mallinfo mspace_mallinfo(mspace msp);
1122 #endif /* NO_MALLINFO */
1123
1124 /*
1125 mspace_malloc_stats behaves as malloc_stats, but reports
1126 properties of the given space.
1127 */
1128 void mspace_malloc_stats(mspace msp);
1129
1130 /*
1131 mspace_trim behaves as malloc_trim, but
1132 operates within the given space.
1133 */
1134 int mspace_trim(mspace msp, size_t pad);
1135
1136 /*
1137 An alias for mallopt.
1138 */
1139 int mspace_mallopt(int, int);
1140
1141 #endif /* MSPACES */
1142
1143 #ifdef __cplusplus
1144 }; /* end of extern "C" */
1145 #endif /* __cplusplus */
1146
1147 /*
1148 ========================================================================
1149 To make a fully customizable malloc.h header file, cut everything
1150 above this line, put into file malloc.h, edit to suit, and #include it
1151 on the next line, as well as in programs that use this malloc.
1152 ========================================================================
1153 */
1154
1155 /* #include "malloc.h" */
1156
1157 /*------------------------------ internal #includes ---------------------- */
1158
1159 #ifdef _MSC_VER
1160 #pragma warning( disable : 4146 ) /* no "unsigned" warnings */
1161 #endif /* _MSC_VER */
1162
1163 #include <stdio.h> /* for printing in malloc_stats */
1164
1165 #ifndef LACKS_ERRNO_H
1166 #include <errno.h> /* for MALLOC_FAILURE_ACTION */
1167 #endif /* LACKS_ERRNO_H */
1168 #if FOOTERS
1169 #include <time.h> /* for magic initialization */
1170 #endif /* FOOTERS */
1171 #ifndef LACKS_STDLIB_H
1172 #include <stdlib.h> /* for abort() */
1173 #endif /* LACKS_STDLIB_H */
1174 #ifdef DEBUG
1175 #if ABORT_ON_ASSERT_FAILURE
1176 #define assert(x) if(!(x)) ABORT
1177 #else /* ABORT_ON_ASSERT_FAILURE */
1178 #include <assert.h>
1179 #endif /* ABORT_ON_ASSERT_FAILURE */
1180 #else /* DEBUG */
1181 #define assert(x)
1182 #endif /* DEBUG */
1183 #ifndef LACKS_STRING_H
1184 #include <string.h> /* for memset etc */
1185 #endif /* LACKS_STRING_H */
1186 #if USE_BUILTIN_FFS
1187 #ifndef LACKS_STRINGS_H
1188 #include <strings.h> /* for ffs */
1189 #endif /* LACKS_STRINGS_H */
1190 #endif /* USE_BUILTIN_FFS */
1191 #if HAVE_MMAP
1192 #ifndef LACKS_SYS_MMAN_H
1193 #include <sys/mman.h> /* for mmap */
1194 #endif /* LACKS_SYS_MMAN_H */
1195 #ifndef LACKS_FCNTL_H
1196 #include <fcntl.h>
1197 #endif /* LACKS_FCNTL_H */
1198 #endif /* HAVE_MMAP */
1199 #if HAVE_MORECORE
1200 #ifndef LACKS_UNISTD_H
1201 #include <unistd.h> /* for sbrk */
1202 #else /* LACKS_UNISTD_H */
1203 #if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
1204 extern void* sbrk(ptrdiff_t);
1205 #endif /* FreeBSD etc */
1206 #endif /* LACKS_UNISTD_H */
1207 #endif /* HAVE_MMAP */
1208
1209 #ifndef WIN32
1210 #ifndef malloc_getpagesize
1211 # ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */
1212 # ifndef _SC_PAGE_SIZE
1213 # define _SC_PAGE_SIZE _SC_PAGESIZE
1214 # endif
1215 # endif
1216 # ifdef _SC_PAGE_SIZE
1217 # define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
1218 # else
1219 # if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
1220 extern size_t getpagesize();
1221 # define malloc_getpagesize getpagesize()
1222 # else
1223 # ifdef WIN32 /* use supplied emulation of getpagesize */
1224 # define malloc_getpagesize getpagesize()
1225 # else
1226 # ifndef LACKS_SYS_PARAM_H
1227 # include <sys/param.h>
1228 # endif
1229 # ifdef EXEC_PAGESIZE
1230 # define malloc_getpagesize EXEC_PAGESIZE
1231 # else
1232 # ifdef NBPG
1233 # ifndef CLSIZE
1234 # define malloc_getpagesize NBPG
1235 # else
1236 # define malloc_getpagesize (NBPG * CLSIZE)
1237 # endif
1238 # else
1239 # ifdef NBPC
1240 # define malloc_getpagesize NBPC
1241 # else
1242 # ifdef PAGESIZE
1243 # define malloc_getpagesize PAGESIZE
1244 # else /* just guess */
1245 # define malloc_getpagesize ((size_t)4096U)
1246 # endif
1247 # endif
1248 # endif
1249 # endif
1250 # endif
1251 # endif
1252 # endif
1253 #endif
1254 #endif
1255
1256 /* ------------------- size_t and alignment properties -------------------- */
1257
1258 /* The byte and bit size of a size_t */
1259 #define SIZE_T_SIZE (sizeof(size_t))
1260 #define SIZE_T_BITSIZE (sizeof(size_t) << 3)
1261
1262 /* Some constants coerced to size_t */
1263 /* Annoying but necessary to avoid errors on some platforms */
1264 #define SIZE_T_ZERO ((size_t)0)
1265 #define SIZE_T_ONE ((size_t)1)
1266 #define SIZE_T_TWO ((size_t)2)
1267 #define TWO_SIZE_T_SIZES (SIZE_T_SIZE<<1)
1268 #define FOUR_SIZE_T_SIZES (SIZE_T_SIZE<<2)
1269 #define SIX_SIZE_T_SIZES (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES)
1270 #define HALF_MAX_SIZE_T (MAX_SIZE_T / 2U)
1271
1272 /* The bit mask value corresponding to MALLOC_ALIGNMENT */
1273 #define CHUNK_ALIGN_MASK (MALLOC_ALIGNMENT - SIZE_T_ONE)
1274
1275 /* True if address a has acceptable alignment */
1276 #define is_aligned(A) (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0)
1277
1278 /* the number of bytes to offset an address to align it */
1279 #define align_offset(A)\
1280 ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\
1281 ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK))
1282
1283 /* -------------------------- MMAP preliminaries ------------------------- */
1284
1285 /*
1286 If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and
1287 checks to fail so compiler optimizer can delete code rather than
1288 using so many "#if"s.
1289 */
1290
1291
1292 /* MORECORE and MMAP must return MFAIL on failure */
1293 #define MFAIL ((void*)(MAX_SIZE_T))
1294 #define CMFAIL ((char*)(MFAIL)) /* defined for convenience */
1295
1296 #if !HAVE_MMAP
1297 #define IS_MMAPPED_BIT (SIZE_T_ZERO)
1298 #define USE_MMAP_BIT (SIZE_T_ZERO)
1299 #define CALL_MMAP(s) MFAIL
1300 #define CALL_MUNMAP(a, s) (-1)
1301 #define DIRECT_MMAP(s) MFAIL
1302
1303 #else /* HAVE_MMAP */
1304 #define IS_MMAPPED_BIT (SIZE_T_ONE)
1305 #define USE_MMAP_BIT (SIZE_T_ONE)
1306
1307 #if !defined(WIN32) && !defined (__OS2__)
1308 #define CALL_MUNMAP(a, s) munmap((a), (s))
1309 #define MMAP_PROT (PROT_READ|PROT_WRITE)
1310 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
1311 #define MAP_ANONYMOUS MAP_ANON
1312 #endif /* MAP_ANON */
1313 #ifdef MAP_ANONYMOUS
1314 #define MMAP_FLAGS (MAP_PRIVATE|MAP_ANONYMOUS)
1315 #define CALL_MMAP(s) mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
1316 #else /* MAP_ANONYMOUS */
1317 /*
1318 Nearly all versions of mmap support MAP_ANONYMOUS, so the following
1319 is unlikely to be needed, but is supplied just in case.
1320 */
1321 #define MMAP_FLAGS (MAP_PRIVATE)
1322 static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */
1323 #define CALL_MMAP(s) ((dev_zero_fd < 0) ? \
1324 (dev_zero_fd = open("/dev/zero", O_RDWR), \
1325 mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \
1326 mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0))
1327 #endif /* MAP_ANONYMOUS */
1328
1329 #define DIRECT_MMAP(s) CALL_MMAP(s)
1330
1331 #elif defined(__OS2__)
1332
1333 /* OS/2 MMAP via DosAllocMem */
1334 static void* os2mmap(size_t size) {
1335 void* ptr;
1336 if (DosAllocMem(&ptr, size, OBJ_ANY|PAG_COMMIT|PAG_READ|PAG_WRITE) &&
1337 DosAllocMem(&ptr, size, PAG_COMMIT|PAG_READ|PAG_WRITE))
1338 return MFAIL;
1339 return ptr;
1340 }
1341
1342 #define os2direct_mmap(n) os2mmap(n)
1343
1344 /* This function supports releasing coalesed segments */
1345 static int os2munmap(void* ptr, size_t size) {
1346 while (size) {
1347 ULONG ulSize = size;
1348 ULONG ulFlags = 0;
1349 if (DosQueryMem(ptr, &ulSize, &ulFlags) != 0)
1350 return -1;
1351 if ((ulFlags & PAG_BASE) == 0 ||(ulFlags & PAG_COMMIT) == 0 ||
1352 ulSize > size)
1353 return -1;
1354 if (DosFreeMem(ptr) != 0)
1355 return -1;
1356 ptr = ( void * ) ( ( char * ) ptr + ulSize );
1357 size -= ulSize;
1358 }
1359 return 0;
1360 }
1361
1362 #define CALL_MMAP(s) os2mmap(s)
1363 #define CALL_MUNMAP(a, s) os2munmap((a), (s))
1364 #define DIRECT_MMAP(s) os2direct_mmap(s)
1365
1366 #else /* WIN32 */
1367
1368 /* Win32 MMAP via VirtualAlloc */
1369 static void* win32mmap(size_t size) {
1370 void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT, PAGE_EXECUTE_READWRITE);
1371 return (ptr != 0)? ptr: MFAIL;
1372 }
1373
1374 /* For direct MMAP, use MEM_TOP_DOWN to minimize interference */
1375 static void* win32direct_mmap(size_t size) {
1376 void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN,
1377 PAGE_EXECUTE_READWRITE);
1378 return (ptr != 0)? ptr: MFAIL;
1379 }
1380
1381 /* This function supports releasing coalesed segments */
1382 static int win32munmap(void* ptr, size_t size) {
1383 MEMORY_BASIC_INFORMATION minfo;
1384 char* cptr = ptr;
1385 while (size) {
1386 if (VirtualQuery(cptr, &minfo, sizeof(minfo)) == 0)
1387 return -1;
1388 if (minfo.BaseAddress != cptr || minfo.AllocationBase != cptr ||
1389 minfo.State != MEM_COMMIT || minfo.RegionSize > size)
1390 return -1;
1391 if (VirtualFree(cptr, 0, MEM_RELEASE) == 0)
1392 return -1;
1393 cptr += minfo.RegionSize;
1394 size -= minfo.RegionSize;
1395 }
1396 return 0;
1397 }
1398
1399 #define CALL_MMAP(s) win32mmap(s)
1400 #define CALL_MUNMAP(a, s) win32munmap((a), (s))
1401 #define DIRECT_MMAP(s) win32direct_mmap(s)
1402 #endif /* WIN32 */
1403 #endif /* HAVE_MMAP */
1404
1405 #if HAVE_MMAP && HAVE_MREMAP
1406 #define CALL_MREMAP(addr, osz, nsz, mv) mremap((addr), (osz), (nsz), (mv))
1407 #else /* HAVE_MMAP && HAVE_MREMAP */
1408 #define CALL_MREMAP(addr, osz, nsz, mv) MFAIL
1409 #endif /* HAVE_MMAP && HAVE_MREMAP */
1410
1411 #if HAVE_MORECORE
1412 #define CALL_MORECORE(S) MORECORE(S)
1413 #else /* HAVE_MORECORE */
1414 #define CALL_MORECORE(S) MFAIL
1415 #endif /* HAVE_MORECORE */
1416
1417 /* mstate bit set if contiguous morecore disabled or failed */
1418 #define USE_NONCONTIGUOUS_BIT (4U)
1419
1420 /* segment bit set in create_mspace_with_base */
1421 #define EXTERN_BIT (8U)
1422
1423
1424 /* --------------------------- Lock preliminaries ------------------------ */
1425
1426 #if USE_LOCKS
1427
1428 /*
1429 When locks are defined, there are up to two global locks:
1430
1431 * If HAVE_MORECORE, morecore_mutex protects sequences of calls to
1432 MORECORE. In many cases sys_alloc requires two calls, that should
1433 not be interleaved with calls by other threads. This does not
1434 protect against direct calls to MORECORE by other threads not
1435 using this lock, so there is still code to cope the best we can on
1436 interference.
1437
1438 * magic_init_mutex ensures that mparams.magic and other
1439 unique mparams values are initialized only once.
1440 */
1441
1442 #if !defined(WIN32) && !defined(__OS2__)
1443 /* By default use posix locks */
1444 #include <pthread.h>
1445 #define MLOCK_T pthread_mutex_t
1446 #define INITIAL_LOCK(l) pthread_mutex_init(l, NULL)
1447 #define ACQUIRE_LOCK(l) pthread_mutex_lock(l)
1448 #define RELEASE_LOCK(l) pthread_mutex_unlock(l)
1449
1450 #if HAVE_MORECORE
1451 static MLOCK_T morecore_mutex = PTHREAD_MUTEX_INITIALIZER;
1452 #endif /* HAVE_MORECORE */
1453
1454 static MLOCK_T magic_init_mutex = PTHREAD_MUTEX_INITIALIZER;
1455
1456 #elif defined(__OS2__)
1457 #define MLOCK_T HMTX
1458 #define INITIAL_LOCK(l) DosCreateMutexSem(0, l, 0, FALSE)
1459 #define ACQUIRE_LOCK(l) DosRequestMutexSem(*l, SEM_INDEFINITE_WAIT)
1460 #define RELEASE_LOCK(l) DosReleaseMutexSem(*l)
1461 #if HAVE_MORECORE
1462 static MLOCK_T morecore_mutex;
1463 #endif /* HAVE_MORECORE */
1464 static MLOCK_T magic_init_mutex;
1465
1466 #else /* WIN32 */
1467 /*
1468 Because lock-protected regions have bounded times, and there
1469 are no recursive lock calls, we can use simple spinlocks.
1470 */
1471
1472 #define MLOCK_T long
1473 static int win32_acquire_lock (MLOCK_T *sl) {
1474 for (;;) {
1475 #ifdef InterlockedCompareExchangePointer
1476 if (!InterlockedCompareExchange(sl, 1, 0))
1477 return 0;
1478 #else /* Use older void* version */
1479 if (!InterlockedCompareExchange((void**)sl, (void*)1, (void*)0))
1480 return 0;
1481 #endif /* InterlockedCompareExchangePointer */
1482 Sleep (0);
1483 }
1484 }
1485
1486 static void win32_release_lock (MLOCK_T *sl) {
1487 InterlockedExchange (sl, 0);
1488 }
1489
1490 #define INITIAL_LOCK(l) *(l)=0
1491 #define ACQUIRE_LOCK(l) win32_acquire_lock(l)
1492 #define RELEASE_LOCK(l) win32_release_lock(l)
1493 #if HAVE_MORECORE
1494 static MLOCK_T morecore_mutex;
1495 #endif /* HAVE_MORECORE */
1496 static MLOCK_T magic_init_mutex;
1497 #endif /* WIN32 */
1498
1499 #define USE_LOCK_BIT (2U)
1500 #else /* USE_LOCKS */
1501 #define USE_LOCK_BIT (0U)
1502 #define INITIAL_LOCK(l)
1503 #endif /* USE_LOCKS */
1504
1505 #if USE_LOCKS && HAVE_MORECORE
1506 #define ACQUIRE_MORECORE_LOCK() ACQUIRE_LOCK(&morecore_mutex);
1507 #define RELEASE_MORECORE_LOCK() RELEASE_LOCK(&morecore_mutex);
1508 #else /* USE_LOCKS && HAVE_MORECORE */
1509 #define ACQUIRE_MORECORE_LOCK()
1510 #define RELEASE_MORECORE_LOCK()
1511 #endif /* USE_LOCKS && HAVE_MORECORE */
1512
1513 #if USE_LOCKS
1514 #define ACQUIRE_MAGIC_INIT_LOCK() ACQUIRE_LOCK(&magic_init_mutex);
1515 #define RELEASE_MAGIC_INIT_LOCK() RELEASE_LOCK(&magic_init_mutex);
1516 #else /* USE_LOCKS */
1517 #define ACQUIRE_MAGIC_INIT_LOCK()
1518 #define RELEASE_MAGIC_INIT_LOCK()
1519 #endif /* USE_LOCKS */
1520
1521
1522 /* ----------------------- Chunk representations ------------------------ */
1523
1524 /*
1525 (The following includes lightly edited explanations by Colin Plumb.)
1526
1527 The malloc_chunk declaration below is misleading (but accurate and
1528 necessary). It declares a "view" into memory allowing access to
1529 necessary fields at known offsets from a given base.
1530
1531 Chunks of memory are maintained using a `boundary tag' method as
1532 originally described by Knuth. (See the paper by Paul Wilson
1533 ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such
1534 techniques.) Sizes of free chunks are stored both in the front of
1535 each chunk and at the end. This makes consolidating fragmented
1536 chunks into bigger chunks fast. The head fields also hold bits
1537 representing whether chunks are free or in use.
1538
1539 Here are some pictures to make it clearer. They are "exploded" to
1540 show that the state of a chunk can be thought of as extending from
1541 the high 31 bits of the head field of its header through the
1542 prev_foot and PINUSE_BIT bit of the following chunk header.
1543
1544 A chunk that's in use looks like:
1545
1546 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1547 | Size of previous chunk (if P = 1) |
1548 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
1550 | Size of this chunk 1| +-+
1551 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1552 | |
1553 +- -+
1554 | |
1555 +- -+
1556 | :
1557 +- size - sizeof(size_t) available payload bytes -+
1558 : |
1559 chunk-> +- -+
1560 | |
1561 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1562 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|
1563 | Size of next chunk (may or may not be in use) | +-+
1564 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1565
1566 And if it's free, it looks like this:
1567
1568 chunk-> +- -+
1569 | User payload (must be in use, or we would have merged!) |
1570 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1571 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
1572 | Size of this chunk 0| +-+
1573 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1574 | Next pointer |
1575 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1576 | Prev pointer |
1577 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1578 | :
1579 +- size - sizeof(struct chunk) unused bytes -+
1580 : |
1581 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1582 | Size of this chunk |
1583 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|
1585 | Size of next chunk (must be in use, or we would have merged)| +-+
1586 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1587 | :
1588 +- User payload -+
1589 : |
1590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1591 |0|
1592 +-+
1593 Note that since we always merge adjacent free chunks, the chunks
1594 adjacent to a free chunk must be in use.
1595
1596 Given a pointer to a chunk (which can be derived trivially from the
1597 payload pointer) we can, in O(1) time, find out whether the adjacent
1598 chunks are free, and if so, unlink them from the lists that they
1599 are on and merge them with the current chunk.
1600
1601 Chunks always begin on even word boundaries, so the mem portion
1602 (which is returned to the user) is also on an even word boundary, and
1603 thus at least double-word aligned.
1604
1605 The P (PINUSE_BIT) bit, stored in the unused low-order bit of the
1606 chunk size (which is always a multiple of two words), is an in-use
1607 bit for the *previous* chunk. If that bit is *clear*, then the
1608 word before the current chunk size contains the previous chunk
1609 size, and can be used to find the front of the previous chunk.
1610 The very first chunk allocated always has this bit set, preventing
1611 access to non-existent (or non-owned) memory. If pinuse is set for
1612 any given chunk, then you CANNOT determine the size of the
1613 previous chunk, and might even get a memory addressing fault when
1614 trying to do so.
1615
1616 The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of
1617 the chunk size redundantly records whether the current chunk is
1618 inuse. This redundancy enables usage checks within free and realloc,
1619 and reduces indirection when freeing and consolidating chunks.
1620
1621 Each freshly allocated chunk must have both cinuse and pinuse set.
1622 That is, each allocated chunk borders either a previously allocated
1623 and still in-use chunk, or the base of its memory arena. This is
1624 ensured by making all allocations from the the `lowest' part of any
1625 found chunk. Further, no free chunk physically borders another one,
1626 so each free chunk is known to be preceded and followed by either
1627 inuse chunks or the ends of memory.
1628
1629 Note that the `foot' of the current chunk is actually represented
1630 as the prev_foot of the NEXT chunk. This makes it easier to
1631 deal with alignments etc but can be very confusing when trying
1632 to extend or adapt this code.
1633
1634 The exceptions to all this are
1635
1636 1. The special chunk `top' is the top-most available chunk (i.e.,
1637 the one bordering the end of available memory). It is treated
1638 specially. Top is never included in any bin, is used only if
1639 no other chunk is available, and is released back to the
1640 system if it is very large (see M_TRIM_THRESHOLD). In effect,
1641 the top chunk is treated as larger (and thus less well
1642 fitting) than any other available chunk. The top chunk
1643 doesn't update its trailing size field since there is no next
1644 contiguous chunk that would have to index off it. However,
1645 space is still allocated for it (TOP_FOOT_SIZE) to enable
1646 separation or merging when space is extended.
1647
1648 3. Chunks allocated via mmap, which have the lowest-order bit
1649 (IS_MMAPPED_BIT) set in their prev_foot fields, and do not set
1650 PINUSE_BIT in their head fields. Because they are allocated
1651 one-by-one, each must carry its own prev_foot field, which is
1652 also used to hold the offset this chunk has within its mmapped
1653 region, which is needed to preserve alignment. Each mmapped
1654 chunk is trailed by the first two fields of a fake next-chunk
1655 for sake of usage checks.
1656
1657 */
1658
1659 struct malloc_chunk {
1660 size_t prev_foot; /* Size of previous chunk (if free). */
1661 size_t head; /* Size and inuse bits. */
1662 struct malloc_chunk* fd; /* double links -- used only if free. */
1663 struct malloc_chunk* bk;
1664 };
1665
1666 typedef struct malloc_chunk mchunk;
1667 typedef struct malloc_chunk* mchunkptr;
1668 typedef struct malloc_chunk* sbinptr; /* The type of bins of chunks */
1669 typedef size_t bindex_t; /* Described below */
1670 typedef unsigned int binmap_t; /* Described below */
1671 typedef unsigned int flag_t; /* The type of various bit flag sets */
1672
1673 /* ------------------- Chunks sizes and alignments ----------------------- */
1674
1675 #define MCHUNK_SIZE (sizeof(mchunk))
1676
1677 #if FOOTERS
1678 #define CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
1679 #else /* FOOTERS */
1680 #define CHUNK_OVERHEAD (SIZE_T_SIZE)
1681 #endif /* FOOTERS */
1682
1683 /* MMapped chunks need a second word of overhead ... */
1684 #define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
1685 /* ... and additional padding for fake next-chunk at foot */
1686 #define MMAP_FOOT_PAD (FOUR_SIZE_T_SIZES)
1687
1688 /* The smallest size we can malloc is an aligned minimal chunk */
1689 #define MIN_CHUNK_SIZE\
1690 ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
1691
1692 /* conversion from malloc headers to user pointers, and back */
1693 #define chunk2mem(p) ((void*)((char*)(p) + TWO_SIZE_T_SIZES))
1694 #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
1695 /* chunk associated with aligned address A */
1696 #define align_as_chunk(A) (mchunkptr)((A) + align_offset(chunk2mem(A)))
1697
1698 /* Bounds on request (not chunk) sizes. */
1699 #define MAX_REQUEST ((-MIN_CHUNK_SIZE) << 2)
1700 #define MIN_REQUEST (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)
1701
1702 /* pad request bytes into a usable size */
1703 #define pad_request(req) \
1704 (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
1705
1706 /* pad request, checking for minimum (but not maximum) */
1707 #define request2size(req) \
1708 (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))
1709
1710
1711 /* ------------------ Operations on head and foot fields ----------------- */
1712
1713 /*
1714 The head field of a chunk is or'ed with PINUSE_BIT when previous
1715 adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in
1716 use. If the chunk was obtained with mmap, the prev_foot field has
1717 IS_MMAPPED_BIT set, otherwise holding the offset of the base of the
1718 mmapped region to the base of the chunk.
1719 */
1720
1721 #define PINUSE_BIT (SIZE_T_ONE)
1722 #define CINUSE_BIT (SIZE_T_TWO)
1723 #define INUSE_BITS (PINUSE_BIT|CINUSE_BIT)
1724
1725 /* Head value for fenceposts */
1726 #define FENCEPOST_HEAD (INUSE_BITS|SIZE_T_SIZE)
1727
1728 /* extraction of fields from head words */
1729 #define cinuse(p) ((p)->head & CINUSE_BIT)
1730 #define pinuse(p) ((p)->head & PINUSE_BIT)
1731 #define chunksize(p) ((p)->head & ~(INUSE_BITS))
1732
1733 #define clear_pinuse(p) ((p)->head &= ~PINUSE_BIT)
1734 #define clear_cinuse(p) ((p)->head &= ~CINUSE_BIT)
1735
1736 /* Treat space at ptr +/- offset as a chunk */
1737 #define chunk_plus_offset(p, s) ((mchunkptr)(((char*)(p)) + (s)))
1738 #define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s)))
1739
1740 /* Ptr to next or previous physical malloc_chunk. */
1741 #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~INUSE_BITS)))
1742 #define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) ))
1743
1744 /* extract next chunk's pinuse bit */
1745 #define next_pinuse(p) ((next_chunk(p)->head) & PINUSE_BIT)
1746
1747 /* Get/set size at footer */
1748 #define get_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot)
1749 #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s))
1750
1751 /* Set size, pinuse bit, and foot */
1752 #define set_size_and_pinuse_of_free_chunk(p, s)\
1753 ((p)->head = (s|PINUSE_BIT), set_foot(p, s))
1754
1755 /* Set size, pinuse bit, foot, and clear next pinuse */
1756 #define set_free_with_pinuse(p, s, n)\
1757 (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s))
1758
1759 #define is_mmapped(p)\
1760 (!((p)->head & PINUSE_BIT) && ((p)->prev_foot & IS_MMAPPED_BIT))
1761
1762 /* Get the internal overhead associated with chunk p */
1763 #define overhead_for(p)\
1764 (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD)
1765
1766 /* Return true if malloced space is not necessarily cleared */
1767 #if MMAP_CLEARS
1768 #define calloc_must_clear(p) (!is_mmapped(p))
1769 #else /* MMAP_CLEARS */
1770 #define calloc_must_clear(p) (1)
1771 #endif /* MMAP_CLEARS */
1772
1773 /* ---------------------- Overlaid data structures ----------------------- */
1774
1775 /*
1776 When chunks are not in use, they are treated as nodes of either
1777 lists or trees.
1778
1779 "Small" chunks are stored in circular doubly-linked lists, and look
1780 like this:
1781
1782 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1783 | Size of previous chunk |
1784 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1785 `head:' | Size of chunk, in bytes |P|
1786 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1787 | Forward pointer to next chunk in list |
1788 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1789 | Back pointer to previous chunk in list |
1790 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1791 | Unused space (may be 0 bytes long) .
1792 . .
1793 . |
1794 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1795 `foot:' | Size of chunk, in bytes |
1796 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1797
1798 Larger chunks are kept in a form of bitwise digital trees (aka
1799 tries) keyed on chunksizes. Because malloc_tree_chunks are only for
1800 free chunks greater than 256 bytes, their size doesn't impose any
1801 constraints on user chunk sizes. Each node looks like:
1802
1803 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1804 | Size of previous chunk |
1805 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1806 `head:' | Size of chunk, in bytes |P|
1807 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1808 | Forward pointer to next chunk of same size |
1809 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1810 | Back pointer to previous chunk of same size |
1811 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1812 | Pointer to left child (child[0]) |
1813 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1814 | Pointer to right child (child[1]) |
1815 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1816 | Pointer to parent |
1817 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1818 | bin index of this chunk |
1819 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1820 | Unused space .
1821 . |
1822 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1823 `foot:' | Size of chunk, in bytes |
1824 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1825
1826 Each tree holding treenodes is a tree of unique chunk sizes. Chunks
1827 of the same size are arranged in a circularly-linked list, with only
1828 the oldest chunk (the next to be used, in our FIFO ordering)
1829 actually in the tree. (Tree members are distinguished by a non-null
1830 parent pointer.) If a chunk with the same size an an existing node
1831 is inserted, it is linked off the existing node using pointers that
1832 work in the same way as fd/bk pointers of small chunks.
1833
1834 Each tree contains a power of 2 sized range of chunk sizes (the
1835 smallest is 0x100 <= x < 0x180), which is is divided in half at each
1836 tree level, with the chunks in the smaller half of the range (0x100
1837 <= x < 0x140 for the top nose) in the left subtree and the larger
1838 half (0x140 <= x < 0x180) in the right subtree. This is, of course,
1839 done by inspecting individual bits.
1840
1841 Using these rules, each node's left subtree contains all smaller
1842 sizes than its right subtree. However, the node at the root of each
1843 subtree has no particular ordering relationship to either. (The
1844 dividing line between the subtree sizes is based on trie relation.)
1845 If we remove the last chunk of a given size from the interior of the
1846 tree, we need to replace it with a leaf node. The tree ordering
1847 rules permit a node to be replaced by any leaf below it.
1848
1849 The smallest chunk in a tree (a common operation in a best-fit
1850 allocator) can be found by walking a path to the leftmost leaf in
1851 the tree. Unlike a usual binary tree, where we follow left child
1852 pointers until we reach a null, here we follow the right child
1853 pointer any time the left one is null, until we reach a leaf with
1854 both child pointers null. The smallest chunk in the tree will be
1855 somewhere along that path.
1856
1857 The worst case number of steps to add, find, or remove a node is
1858 bounded by the number of bits differentiating chunks within
1859 bins. Under current bin calculations, this ranges from 6 up to 21
1860 (for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case
1861 is of course much better.
1862 */
1863
1864 struct malloc_tree_chunk {
1865 /* The first four fields must be compatible with malloc_chunk */
1866 size_t prev_foot;
1867 size_t head;
1868 struct malloc_tree_chunk* fd;
1869 struct malloc_tree_chunk* bk;
1870
1871 struct malloc_tree_chunk* child[2];
1872 struct malloc_tree_chunk* parent;
1873 bindex_t index;
1874 };
1875
1876 typedef struct malloc_tree_chunk tchunk;
1877 typedef struct malloc_tree_chunk* tchunkptr;
1878 typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */
1879
1880 /* A little helper macro for trees */
1881 #define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1])
1882
1883 /* ----------------------------- Segments -------------------------------- */
1884
1885 /*
1886 Each malloc space may include non-contiguous segments, held in a
1887 list headed by an embedded malloc_segment record representing the
1888 top-most space. Segments also include flags holding properties of
1889 the space. Large chunks that are directly allocated by mmap are not
1890 included in this list. They are instead independently created and
1891 destroyed without otherwise keeping track of them.
1892
1893 Segment management mainly comes into play for spaces allocated by
1894 MMAP. Any call to MMAP might or might not return memory that is
1895 adjacent to an existing segment. MORECORE normally contiguously
1896 extends the current space, so this space is almost always adjacent,
1897 which is simpler and faster to deal with. (This is why MORECORE is
1898 used preferentially to MMAP when both are available -- see
1899 sys_alloc.) When allocating using MMAP, we don't use any of the
1900 hinting mechanisms (inconsistently) supported in various
1901 implementations of unix mmap, or distinguish reserving from
1902 committing memory. Instead, we just ask for space, and exploit
1903 contiguity when we get it. It is probably possible to do
1904 better than this on some systems, but no general scheme seems
1905 to be significantly better.
1906
1907 Management entails a simpler variant of the consolidation scheme
1908 used for chunks to reduce fragmentation -- new adjacent memory is
1909 normally prepended or appended to an existing segment. However,
1910 there are limitations compared to chunk consolidation that mostly
1911 reflect the fact that segment processing is relatively infrequent
1912 (occurring only when getting memory from system) and that we
1913 don't expect to have huge numbers of segments:
1914
1915 * Segments are not indexed, so traversal requires linear scans. (It
1916 would be possible to index these, but is not worth the extra
1917 overhead and complexity for most programs on most platforms.)
1918 * New segments are only appended to old ones when holding top-most
1919 memory; if they cannot be prepended to others, they are held in
1920 different segments.
1921
1922 Except for the top-most segment of an mstate, each segment record
1923 is kept at the tail of its segment. Segments are added by pushing
1924 segment records onto the list headed by &mstate.seg for the
1925 containing mstate.
1926
1927 Segment flags control allocation/merge/deallocation policies:
1928 * If EXTERN_BIT set, then we did not allocate this segment,
1929 and so should not try to deallocate or merge with others.
1930 (This currently holds only for the initial segment passed
1931 into create_mspace_with_base.)
1932 * If IS_MMAPPED_BIT set, the segment may be merged with
1933 other surrounding mmapped segments and trimmed/de-allocated
1934 using munmap.
1935 * If neither bit is set, then the segment was obtained using
1936 MORECORE so can be merged with surrounding MORECORE'd segments
1937 and deallocated/trimmed using MORECORE with negative arguments.
1938 */
1939
1940 struct malloc_segment {
1941 char* base; /* base address */
1942 size_t size; /* allocated size */
1943 struct malloc_segment* next; /* ptr to next segment */
1944 #if FFI_MMAP_EXEC_WRIT
1945 /* The mmap magic is supposed to store the address of the executable
1946 segment at the very end of the requested block. */
1947
1948 # define mmap_exec_offset(b,s) (*(ptrdiff_t*)((b)+(s)-sizeof(ptrdiff_t)))
1949
1950 /* We can only merge segments if their corresponding executable
1951 segments are at identical offsets. */
1952 # define check_segment_merge(S,b,s) \
1953 (mmap_exec_offset((b),(s)) == (S)->exec_offset)
1954
1955 # define add_segment_exec_offset(p,S) ((char*)(p) + (S)->exec_offset)
1956 # define sub_segment_exec_offset(p,S) ((char*)(p) - (S)->exec_offset)
1957
1958 /* The removal of sflags only works with HAVE_MORECORE == 0. */
1959
1960 # define get_segment_flags(S) (IS_MMAPPED_BIT)
1961 # define set_segment_flags(S,v) \
1962 (((v) != IS_MMAPPED_BIT) ? (ABORT, (v)) : \
1963 (((S)->exec_offset = \
1964 mmap_exec_offset((S)->base, (S)->size)), \
1965 (mmap_exec_offset((S)->base + (S)->exec_offset, (S)->size) != \
1966 (S)->exec_offset) ? (ABORT, (v)) : \
1967 (mmap_exec_offset((S)->base, (S)->size) = 0), (v)))
1968
1969 /* We use an offset here, instead of a pointer, because then, when
1970 base changes, we don't have to modify this. On architectures
1971 with segmented addresses, this might not work. */
1972 ptrdiff_t exec_offset;
1973 #else
1974
1975 # define get_segment_flags(S) ((S)->sflags)
1976 # define set_segment_flags(S,v) ((S)->sflags = (v))
1977 # define check_segment_merge(S,b,s) (1)
1978
1979 flag_t sflags; /* mmap and extern flag */
1980 #endif
1981 };
1982
1983 #define is_mmapped_segment(S) (get_segment_flags(S) & IS_MMAPPED_BIT)
1984 #define is_extern_segment(S) (get_segment_flags(S) & EXTERN_BIT)
1985
1986 typedef struct malloc_segment msegment;
1987 typedef struct malloc_segment* msegmentptr;
1988
1989 /* ---------------------------- malloc_state ----------------------------- */
1990
1991 /*
1992 A malloc_state holds all of the bookkeeping for a space.
1993 The main fields are:
1994
1995 Top
1996 The topmost chunk of the currently active segment. Its size is
1997 cached in topsize. The actual size of topmost space is
1998 topsize+TOP_FOOT_SIZE, which includes space reserved for adding
1999 fenceposts and segment records if necessary when getting more
2000 space from the system. The size at which to autotrim top is
2001 cached from mparams in trim_check, except that it is disabled if
2002 an autotrim fails.
2003
2004 Designated victim (dv)
2005 This is the preferred chunk for servicing small requests that
2006 don't have exact fits. It is normally the chunk split off most
2007 recently to service another small request. Its size is cached in
2008 dvsize. The link fields of this chunk are not maintained since it
2009 is not kept in a bin.
2010
2011 SmallBins
2012 An array of bin headers for free chunks. These bins hold chunks
2013 with sizes less than MIN_LARGE_SIZE bytes. Each bin contains
2014 chunks of all the same size, spaced 8 bytes apart. To simplify
2015 use in double-linked lists, each bin header acts as a malloc_chunk
2016 pointing to the real first node, if it exists (else pointing to
2017 itself). This avoids special-casing for headers. But to avoid
2018 waste, we allocate only the fd/bk pointers of bins, and then use
2019 repositioning tricks to treat these as the fields of a chunk.
2020
2021 TreeBins
2022 Treebins are pointers to the roots of trees holding a range of
2023 sizes. There are 2 equally spaced treebins for each power of two
2024 from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything
2025 larger.
2026
2027 Bin maps
2028 There is one bit map for small bins ("smallmap") and one for
2029 treebins ("treemap). Each bin sets its bit when non-empty, and
2030 clears the bit when empty. Bit operations are then used to avoid
2031 bin-by-bin searching -- nearly all "search" is done without ever
2032 looking at bins that won't be selected. The bit maps
2033 conservatively use 32 bits per map word, even if on 64bit system.
2034 For a good description of some of the bit-based techniques used
2035 here, see Henry S. Warren Jr's book "Hacker's Delight" (and
2036 supplement at http://hackersdelight.org/). Many of these are
2037 intended to reduce the branchiness of paths through malloc etc, as
2038 well as to reduce the number of memory locations read or written.
2039
2040 Segments
2041 A list of segments headed by an embedded malloc_segment record
2042 representing the initial space.
2043
2044 Address check support
2045 The least_addr field is the least address ever obtained from
2046 MORECORE or MMAP. Attempted frees and reallocs of any address less
2047 than this are trapped (unless INSECURE is defined).
2048
2049 Magic tag
2050 A cross-check field that should always hold same value as mparams.magic.
2051
2052 Flags
2053 Bits recording whether to use MMAP, locks, or contiguous MORECORE
2054
2055 Statistics
2056 Each space keeps track of current and maximum system memory
2057 obtained via MORECORE or MMAP.
2058
2059 Locking
2060 If USE_LOCKS is defined, the "mutex" lock is acquired and released
2061 around every public call using this mspace.
2062 */
2063
2064 /* Bin types, widths and sizes */
2065 #define NSMALLBINS (32U)
2066 #define NTREEBINS (32U)
2067 #define SMALLBIN_SHIFT (3U)
2068 #define SMALLBIN_WIDTH (SIZE_T_ONE << SMALLBIN_SHIFT)
2069 #define TREEBIN_SHIFT (8U)
2070 #define MIN_LARGE_SIZE (SIZE_T_ONE << TREEBIN_SHIFT)
2071 #define MAX_SMALL_SIZE (MIN_LARGE_SIZE - SIZE_T_ONE)
2072 #define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD)
2073
2074 struct malloc_state {
2075 binmap_t smallmap;
2076 binmap_t treemap;
2077 size_t dvsize;
2078 size_t topsize;
2079 char* least_addr;
2080 mchunkptr dv;
2081 mchunkptr top;
2082 size_t trim_check;
2083 size_t magic;
2084 mchunkptr smallbins[(NSMALLBINS+1)*2];
2085 tbinptr treebins[NTREEBINS];
2086 size_t footprint;
2087 size_t max_footprint;
2088 flag_t mflags;
2089 #if USE_LOCKS
2090 MLOCK_T mutex; /* locate lock among fields that rarely change */
2091 #endif /* USE_LOCKS */
2092 msegment seg;
2093 };
2094
2095 typedef struct malloc_state* mstate;
2096
2097 /* ------------- Global malloc_state and malloc_params ------------------- */
2098
2099 /*
2100 malloc_params holds global properties, including those that can be
2101 dynamically set using mallopt. There is a single instance, mparams,
2102 initialized in init_mparams.
2103 */
2104
2105 struct malloc_params {
2106 size_t magic;
2107 size_t page_size;
2108 size_t granularity;
2109 size_t mmap_threshold;
2110 size_t trim_threshold;
2111 flag_t default_mflags;
2112 };
2113
2114 static struct malloc_params mparams;
2115
2116 /* The global malloc_state used for all non-"mspace" calls */
2117 static struct malloc_state _gm_;
2118 #define gm (&_gm_)
2119 #define is_global(M) ((M) == &_gm_)
2120 #define is_initialized(M) ((M)->top != 0)
2121
2122 /* -------------------------- system alloc setup ------------------------- */
2123
2124 /* Operations on mflags */
2125
2126 #define use_lock(M) ((M)->mflags & USE_LOCK_BIT)
2127 #define enable_lock(M) ((M)->mflags |= USE_LOCK_BIT)
2128 #define disable_lock(M) ((M)->mflags &= ~USE_LOCK_BIT)
2129
2130 #define use_mmap(M) ((M)->mflags & USE_MMAP_BIT)
2131 #define enable_mmap(M) ((M)->mflags |= USE_MMAP_BIT)
2132 #define disable_mmap(M) ((M)->mflags &= ~USE_MMAP_BIT)
2133
2134 #define use_noncontiguous(M) ((M)->mflags & USE_NONCONTIGUOUS_BIT)
2135 #define disable_contiguous(M) ((M)->mflags |= USE_NONCONTIGUOUS_BIT)
2136
2137 #define set_lock(M,L)\
2138 ((M)->mflags = (L)?\
2139 ((M)->mflags | USE_LOCK_BIT) :\
2140 ((M)->mflags & ~USE_LOCK_BIT))
2141
2142 /* page-align a size */
2143 #define page_align(S)\
2144 (((S) + (mparams.page_size)) & ~(mparams.page_size - SIZE_T_ONE))
2145
2146 /* granularity-align a size */
2147 #define granularity_align(S)\
2148 (((S) + (mparams.granularity)) & ~(mparams.granularity - SIZE_T_ONE))
2149
2150 #define is_page_aligned(S)\
2151 (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0)
2152 #define is_granularity_aligned(S)\
2153 (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0)
2154
2155 /* True if segment S holds address A */
2156 #define segment_holds(S, A)\
2157 ((char*)(A) >= S->base && (char*)(A) < S->base + S->size)
2158
2159 /* Return segment holding given address */
2160 static msegmentptr segment_holding(mstate m, char* addr) {
2161 msegmentptr sp = &m->seg;
2162 for (;;) {
2163 if (addr >= sp->base && addr < sp->base + sp->size)
2164 return sp;
2165 if ((sp = sp->next) == 0)
2166 return 0;
2167 }
2168 }
2169
2170 /* Return true if segment contains a segment link */
2171 static int has_segment_link(mstate m, msegmentptr ss) {
2172 msegmentptr sp = &m->seg;
2173 for (;;) {
2174 if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size)
2175 return 1;
2176 if ((sp = sp->next) == 0)
2177 return 0;
2178 }
2179 }
2180
2181 #ifndef MORECORE_CANNOT_TRIM
2182 #define should_trim(M,s) ((s) > (M)->trim_check)
2183 #else /* MORECORE_CANNOT_TRIM */
2184 #define should_trim(M,s) (0)
2185 #endif /* MORECORE_CANNOT_TRIM */
2186
2187 /*
2188 TOP_FOOT_SIZE is padding at the end of a segment, including space
2189 that may be needed to place segment records and fenceposts when new
2190 noncontiguous segments are added.
2191 */
2192 #define TOP_FOOT_SIZE\
2193 (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE)
2194
2195
2196 /* ------------------------------- Hooks -------------------------------- */
2197
2198 /*
2199 PREACTION should be defined to return 0 on success, and nonzero on
2200 failure. If you are not using locking, you can redefine these to do
2201 anything you like.
2202 */
2203
2204 #if USE_LOCKS
2205
2206 /* Ensure locks are initialized */
2207 #define GLOBALLY_INITIALIZE() (mparams.page_size == 0 && init_mparams())
2208
2209 #define PREACTION(M) ((GLOBALLY_INITIALIZE() || use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0)
2210 #define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); }
2211 #else /* USE_LOCKS */
2212
2213 #ifndef PREACTION
2214 #define PREACTION(M) (0)
2215 #endif /* PREACTION */
2216
2217 #ifndef POSTACTION
2218 #define POSTACTION(M)
2219 #endif /* POSTACTION */
2220
2221 #endif /* USE_LOCKS */
2222
2223 /*
2224 CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses.
2225 USAGE_ERROR_ACTION is triggered on detected bad frees and
2226 reallocs. The argument p is an address that might have triggered the
2227 fault. It is ignored by the two predefined actions, but might be
2228 useful in custom actions that try to help diagnose errors.
2229 */
2230
2231 #if PROCEED_ON_ERROR
2232
2233 /* A count of the number of corruption errors causing resets */
2234 int malloc_corruption_error_count;
2235
2236 /* default corruption action */
2237 static void reset_on_error(mstate m);
2238
2239 #define CORRUPTION_ERROR_ACTION(m) reset_on_error(m)
2240 #define USAGE_ERROR_ACTION(m, p)
2241
2242 #else /* PROCEED_ON_ERROR */
2243
2244 #ifndef CORRUPTION_ERROR_ACTION
2245 #define CORRUPTION_ERROR_ACTION(m) ABORT
2246 #endif /* CORRUPTION_ERROR_ACTION */
2247
2248 #ifndef USAGE_ERROR_ACTION
2249 #define USAGE_ERROR_ACTION(m,p) ABORT
2250 #endif /* USAGE_ERROR_ACTION */
2251
2252 #endif /* PROCEED_ON_ERROR */
2253
2254 /* -------------------------- Debugging setup ---------------------------- */
2255
2256 #if ! DEBUG
2257
2258 #define check_free_chunk(M,P)
2259 #define check_inuse_chunk(M,P)
2260 #define check_malloced_chunk(M,P,N)
2261 #define check_mmapped_chunk(M,P)
2262 #define check_malloc_state(M)
2263 #define check_top_chunk(M,P)
2264
2265 #else /* DEBUG */
2266 #define check_free_chunk(M,P) do_check_free_chunk(M,P)
2267 #define check_inuse_chunk(M,P) do_check_inuse_chunk(M,P)
2268 #define check_top_chunk(M,P) do_check_top_chunk(M,P)
2269 #define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N)
2270 #define check_mmapped_chunk(M,P) do_check_mmapped_chunk(M,P)
2271 #define check_malloc_state(M) do_check_malloc_state(M)
2272
2273 static void do_check_any_chunk(mstate m, mchunkptr p);
2274 static void do_check_top_chunk(mstate m, mchunkptr p);
2275 static void do_check_mmapped_chunk(mstate m, mchunkptr p);
2276 static void do_check_inuse_chunk(mstate m, mchunkptr p);
2277 static void do_check_free_chunk(mstate m, mchunkptr p);
2278 static void do_check_malloced_chunk(mstate m, void* mem, size_t s);
2279 static void do_check_tree(mstate m, tchunkptr t);
2280 static void do_check_treebin(mstate m, bindex_t i);
2281 static void do_check_smallbin(mstate m, bindex_t i);
2282 static void do_check_malloc_state(mstate m);
2283 static int bin_find(mstate m, mchunkptr x);
2284 static size_t traverse_and_check(mstate m);
2285 #endif /* DEBUG */
2286
2287 /* ---------------------------- Indexing Bins ---------------------------- */
2288
2289 #define is_small(s) (((s) >> SMALLBIN_SHIFT) < NSMALLBINS)
2290 #define small_index(s) ((s) >> SMALLBIN_SHIFT)
2291 #define small_index2size(i) ((i) << SMALLBIN_SHIFT)
2292 #define MIN_SMALL_INDEX (small_index(MIN_CHUNK_SIZE))
2293
2294 /* addressing by index. See above about smallbin repositioning */
2295 #define smallbin_at(M, i) ((sbinptr)((char*)&((M)->smallbins[(i)<<1])))
2296 #define treebin_at(M,i) (&((M)->treebins[i]))
2297
2298 /* assign tree index for size S to variable I */
2299 #if defined(__GNUC__) && defined(__i386__)
2300 #define compute_tree_index(S, I)\
2301 {\
2302 size_t X = S >> TREEBIN_SHIFT;\
2303 if (X == 0)\
2304 I = 0;\
2305 else if (X > 0xFFFF)\
2306 I = NTREEBINS-1;\
2307 else {\
2308 unsigned int K;\
2309 __asm__("bsrl %1,%0\n\t" : "=r" (K) : "rm" (X));\
2310 I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
2311 }\
2312 }
2313 #else /* GNUC */
2314 #define compute_tree_index(S, I)\
2315 {\
2316 size_t X = S >> TREEBIN_SHIFT;\
2317 if (X == 0)\
2318 I = 0;\
2319 else if (X > 0xFFFF)\
2320 I = NTREEBINS-1;\
2321 else {\
2322 unsigned int Y = (unsigned int)X;\
2323 unsigned int N = ((Y - 0x100) >> 16) & 8;\
2324 unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\
2325 N += K;\
2326 N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\
2327 K = 14 - N + ((Y <<= K) >> 15);\
2328 I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\
2329 }\
2330 }
2331 #endif /* GNUC */
2332
2333 /* Bit representing maximum resolved size in a treebin at i */
2334 #define bit_for_tree_index(i) \
2335 (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2)
2336
2337 /* Shift placing maximum resolved bit in a treebin at i as sign bit */
2338 #define leftshift_for_tree_index(i) \
2339 ((i == NTREEBINS-1)? 0 : \
2340 ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2)))
2341
2342 /* The size of the smallest chunk held in bin with index i */
2343 #define minsize_for_tree_index(i) \
2344 ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) | \
2345 (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1)))
2346
2347
2348 /* ------------------------ Operations on bin maps ----------------------- */
2349
2350 /* bit corresponding to given index */
2351 #define idx2bit(i) ((binmap_t)(1) << (i))
2352
2353 /* Mark/Clear bits with given index */
2354 #define mark_smallmap(M,i) ((M)->smallmap |= idx2bit(i))
2355 #define clear_smallmap(M,i) ((M)->smallmap &= ~idx2bit(i))
2356 #define smallmap_is_marked(M,i) ((M)->smallmap & idx2bit(i))
2357
2358 #define mark_treemap(M,i) ((M)->treemap |= idx2bit(i))
2359 #define clear_treemap(M,i) ((M)->treemap &= ~idx2bit(i))
2360 #define treemap_is_marked(M,i) ((M)->treemap & idx2bit(i))
2361
2362 /* index corresponding to given bit */
2363
2364 #if defined(__GNUC__) && defined(__i386__)
2365 #define compute_bit2idx(X, I)\
2366 {\
2367 unsigned int J;\
2368 __asm__("bsfl %1,%0\n\t" : "=r" (J) : "rm" (X));\
2369 I = (bindex_t)J;\
2370 }
2371
2372 #else /* GNUC */
2373 #if USE_BUILTIN_FFS
2374 #define compute_bit2idx(X, I) I = ffs(X)-1
2375
2376 #else /* USE_BUILTIN_FFS */
2377 #define compute_bit2idx(X, I)\
2378 {\
2379 unsigned int Y = X - 1;\
2380 unsigned int K = Y >> (16-4) & 16;\
2381 unsigned int N = K; Y >>= K;\
2382 N += K = Y >> (8-3) & 8; Y >>= K;\
2383 N += K = Y >> (4-2) & 4; Y >>= K;\
2384 N += K = Y >> (2-1) & 2; Y >>= K;\
2385 N += K = Y >> (1-0) & 1; Y >>= K;\
2386 I = (bindex_t)(N + Y);\
2387 }
2388 #endif /* USE_BUILTIN_FFS */
2389 #endif /* GNUC */
2390
2391 /* isolate the least set bit of a bitmap */
2392 #define least_bit(x) ((x) & -(x))
2393
2394 /* mask with all bits to left of least bit of x on */
2395 #define left_bits(x) ((x<<1) | -(x<<1))
2396
2397 /* mask with all bits to left of or equal to least bit of x on */
2398 #define same_or_left_bits(x) ((x) | -(x))
2399
2400
2401 /* ----------------------- Runtime Check Support ------------------------- */
2402
2403 /*
2404 For security, the main invariant is that malloc/free/etc never
2405 writes to a static address other than malloc_state, unless static
2406 malloc_state itself has been corrupted, which cannot occur via
2407 malloc (because of these checks). In essence this means that we
2408 believe all pointers, sizes, maps etc held in malloc_state, but
2409 check all of those linked or offsetted from other embedded data
2410 structures. These checks are interspersed with main code in a way
2411 that tends to minimize their run-time cost.
2412
2413 When FOOTERS is defined, in addition to range checking, we also
2414 verify footer fields of inuse chunks, which can be used guarantee
2415 that the mstate controlling malloc/free is intact. This is a
2416 streamlined version of the approach described by William Robertson
2417 et al in "Run-time Detection of Heap-based Overflows" LISA'03
2418 http://www.usenix.org/events/lisa03/tech/robertson.html The footer
2419 of an inuse chunk holds the xor of its mstate and a random seed,
2420 that is checked upon calls to free() and realloc(). This is
2421 (probablistically) unguessable from outside the program, but can be
2422 computed by any code successfully malloc'ing any chunk, so does not
2423 itself provide protection against code that has already broken
2424 security through some other means. Unlike Robertson et al, we
2425 always dynamically check addresses of all offset chunks (previous,
2426 next, etc). This turns out to be cheaper than relying on hashes.
2427 */
2428
2429 #if !INSECURE
2430 /* Check if address a is at least as high as any from MORECORE or MMAP */
2431 #define ok_address(M, a) ((char*)(a) >= (M)->least_addr)
2432 /* Check if address of next chunk n is higher than base chunk p */
2433 #define ok_next(p, n) ((char*)(p) < (char*)(n))
2434 /* Check if p has its cinuse bit on */
2435 #define ok_cinuse(p) cinuse(p)
2436 /* Check if p has its pinuse bit on */
2437 #define ok_pinuse(p) pinuse(p)
2438
2439 #else /* !INSECURE */
2440 #define ok_address(M, a) (1)
2441 #define ok_next(b, n) (1)
2442 #define ok_cinuse(p) (1)
2443 #define ok_pinuse(p) (1)
2444 #endif /* !INSECURE */
2445
2446 #if (FOOTERS && !INSECURE)
2447 /* Check if (alleged) mstate m has expected magic field */
2448 #define ok_magic(M) ((M)->magic == mparams.magic)
2449 #else /* (FOOTERS && !INSECURE) */
2450 #define ok_magic(M) (1)
2451 #endif /* (FOOTERS && !INSECURE) */
2452
2453
2454 /* In gcc, use __builtin_expect to minimize impact of checks */
2455 #if !INSECURE
2456 #if defined(__GNUC__) && __GNUC__ >= 3
2457 #define RTCHECK(e) __builtin_expect(e, 1)
2458 #else /* GNUC */
2459 #define RTCHECK(e) (e)
2460 #endif /* GNUC */
2461 #else /* !INSECURE */
2462 #define RTCHECK(e) (1)
2463 #endif /* !INSECURE */
2464
2465 /* macros to set up inuse chunks with or without footers */
2466
2467 #if !FOOTERS
2468
2469 #define mark_inuse_foot(M,p,s)
2470
2471 /* Set cinuse bit and pinuse bit of next chunk */
2472 #define set_inuse(M,p,s)\
2473 ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
2474 ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
2475
2476 /* Set cinuse and pinuse of this chunk and pinuse of next chunk */
2477 #define set_inuse_and_pinuse(M,p,s)\
2478 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
2479 ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
2480
2481 /* Set size, cinuse and pinuse bit of this chunk */
2482 #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
2483 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT))
2484
2485 #else /* FOOTERS */
2486
2487 /* Set foot of inuse chunk to be xor of mstate and seed */
2488 #define mark_inuse_foot(M,p,s)\
2489 (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic))
2490
2491 #define get_mstate_for(p)\
2492 ((mstate)(((mchunkptr)((char*)(p) +\
2493 (chunksize(p))))->prev_foot ^ mparams.magic))
2494
2495 #define set_inuse(M,p,s)\
2496 ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
2497 (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \
2498 mark_inuse_foot(M,p,s))
2499
2500 #define set_inuse_and_pinuse(M,p,s)\
2501 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
2502 (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\
2503 mark_inuse_foot(M,p,s))
2504
2505 #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
2506 ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
2507 mark_inuse_foot(M, p, s))
2508
2509 #endif /* !FOOTERS */
2510
2511 /* ---------------------------- setting mparams -------------------------- */
2512
2513 /* Initialize mparams */
2514 static int init_mparams(void) {
2515 if (mparams.page_size == 0) {
2516 size_t s;
2517
2518 mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD;
2519 mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD;
2520 #if MORECORE_CONTIGUOUS
2521 mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT;
2522 #else /* MORECORE_CONTIGUOUS */
2523 mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT;
2524 #endif /* MORECORE_CONTIGUOUS */
2525
2526 #if (FOOTERS && !INSECURE)
2527 {
2528 #if USE_DEV_RANDOM
2529 int fd;
2530 unsigned char buf[sizeof(size_t)];
2531 /* Try to use /dev/urandom, else fall back on using time */
2532 if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 &&
2533 read(fd, buf, sizeof(buf)) == sizeof(buf)) {
2534 s = *((size_t *) buf);
2535 close(fd);
2536 }
2537 else
2538 #endif /* USE_DEV_RANDOM */
2539 s = (size_t)(time(0) ^ (size_t)0x55555555U);
2540
2541 s |= (size_t)8U; /* ensure nonzero */
2542 s &= ~(size_t)7U; /* improve chances of fault for bad values */
2543
2544 }
2545 #else /* (FOOTERS && !INSECURE) */
2546 s = (size_t)0x58585858U;
2547 #endif /* (FOOTERS && !INSECURE) */
2548 ACQUIRE_MAGIC_INIT_LOCK();
2549 if (mparams.magic == 0) {
2550 mparams.magic = s;
2551 /* Set up lock for main malloc area */
2552 INITIAL_LOCK(&gm->mutex);
2553 gm->mflags = mparams.default_mflags;
2554 }
2555 RELEASE_MAGIC_INIT_LOCK();
2556
2557 #if !defined(WIN32) && !defined(__OS2__)
2558 mparams.page_size = malloc_getpagesize;
2559 mparams.granularity = ((DEFAULT_GRANULARITY != 0)?
2560 DEFAULT_GRANULARITY : mparams.page_size);
2561 #elif defined (__OS2__)
2562 /* if low-memory is used, os2munmap() would break
2563 if it were anything other than 64k */
2564 mparams.page_size = 4096u;
2565 mparams.granularity = 65536u;
2566 #else /* WIN32 */
2567 {
2568 SYSTEM_INFO system_info;
2569 GetSystemInfo(&system_info);
2570 mparams.page_size = system_info.dwPageSize;
2571 mparams.granularity = system_info.dwAllocationGranularity;
2572 }
2573 #endif /* WIN32 */
2574
2575 /* Sanity-check configuration:
2576 size_t must be unsigned and as wide as pointer type.
2577 ints must be at least 4 bytes.
2578 alignment must be at least 8.
2579 Alignment, min chunk size, and page size must all be powers of 2.
2580 */
2581 if ((sizeof(size_t) != sizeof(char*)) ||
2582 (MAX_SIZE_T < MIN_CHUNK_SIZE) ||
2583 (sizeof(int) < 4) ||
2584 (MALLOC_ALIGNMENT < (size_t)8U) ||
2585 ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-SIZE_T_ONE)) != 0) ||
2586 ((MCHUNK_SIZE & (MCHUNK_SIZE-SIZE_T_ONE)) != 0) ||
2587 ((mparams.granularity & (mparams.granularity-SIZE_T_ONE)) != 0) ||
2588 ((mparams.page_size & (mparams.page_size-SIZE_T_ONE)) != 0))
2589 ABORT;
2590 }
2591 return 0;
2592 }
2593
2594 /* support for mallopt */
2595 static int change_mparam(int param_number, int value) {
2596 size_t val = (size_t)value;
2597 init_mparams();
2598 switch(param_number) {
2599 case M_TRIM_THRESHOLD:
2600 mparams.trim_threshold = val;
2601 return 1;
2602 case M_GRANULARITY:
2603 if (val >= mparams.page_size && ((val & (val-1)) == 0)) {
2604 mparams.granularity = val;
2605 return 1;
2606 }
2607 else
2608 return 0;
2609 case M_MMAP_THRESHOLD:
2610 mparams.mmap_threshold = val;
2611 return 1;
2612 default:
2613 return 0;
2614 }
2615 }
2616
2617 #if DEBUG
2618 /* ------------------------- Debugging Support --------------------------- */
2619
2620 /* Check properties of any chunk, whether free, inuse, mmapped etc */
2621 static void do_check_any_chunk(mstate m, mchunkptr p) {
2622 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
2623 assert(ok_address(m, p));
2624 }
2625
2626 /* Check properties of top chunk */
2627 static void do_check_top_chunk(mstate m, mchunkptr p) {
2628 msegmentptr sp = segment_holding(m, (char*)p);
2629 size_t sz = chunksize(p);
2630 assert(sp != 0);
2631 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
2632 assert(ok_address(m, p));
2633 assert(sz == m->topsize);
2634 assert(sz > 0);
2635 assert(sz == ((sp->base + sp->size) - (char*)p) - TOP_FOOT_SIZE);
2636 assert(pinuse(p));
2637 assert(!next_pinuse(p));
2638 }
2639
2640 /* Check properties of (inuse) mmapped chunks */
2641 static void do_check_mmapped_chunk(mstate m, mchunkptr p) {
2642 size_t sz = chunksize(p);
2643 size_t len = (sz + (p->prev_foot & ~IS_MMAPPED_BIT) + MMAP_FOOT_PAD);
2644 assert(is_mmapped(p));
2645 assert(use_mmap(m));
2646 assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
2647 assert(ok_address(m, p));
2648 assert(!is_small(sz));
2649 assert((len & (mparams.page_size-SIZE_T_ONE)) == 0);
2650 assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD);
2651 assert(chunk_plus_offset(p, sz+SIZE_T_SIZE)->head == 0);
2652 }
2653
2654 /* Check properties of inuse chunks */
2655 static void do_check_inuse_chunk(mstate m, mchunkptr p) {
2656 do_check_any_chunk(m, p);
2657 assert(cinuse(p));
2658 assert(next_pinuse(p));
2659 /* If not pinuse and not mmapped, previous chunk has OK offset */
2660 assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p);
2661 if (is_mmapped(p))
2662 do_check_mmapped_chunk(m, p);
2663 }
2664
2665 /* Check properties of free chunks */
2666 static void do_check_free_chunk(mstate m, mchunkptr p) {
2667 size_t sz = p->head & ~(PINUSE_BIT|CINUSE_BIT);
2668 mchunkptr next = chunk_plus_offset(p, sz);
2669 do_check_any_chunk(m, p);
2670 assert(!cinuse(p));
2671 assert(!next_pinuse(p));
2672 assert (!is_mmapped(p));
2673 if (p != m->dv && p != m->top) {
2674 if (sz >= MIN_CHUNK_SIZE) {
2675 assert((sz & CHUNK_ALIGN_MASK) == 0);
2676 assert(is_aligned(chunk2mem(p)));
2677 assert(next->prev_foot == sz);
2678 assert(pinuse(p));
2679 assert (next == m->top || cinuse(next));
2680 assert(p->fd->bk == p);
2681 assert(p->bk->fd == p);
2682 }
2683 else /* markers are always of size SIZE_T_SIZE */
2684 assert(sz == SIZE_T_SIZE);
2685 }
2686 }
2687
2688 /* Check properties of malloced chunks at the point they are malloced */
2689 static void do_check_malloced_chunk(mstate m, void* mem, size_t s) {
2690 if (mem != 0) {
2691 mchunkptr p = mem2chunk(mem);
2692 size_t sz = p->head & ~(PINUSE_BIT|CINUSE_BIT);
2693 do_check_inuse_chunk(m, p);
2694 assert((sz & CHUNK_ALIGN_MASK) == 0);
2695 assert(sz >= MIN_CHUNK_SIZE);
2696 assert(sz >= s);
2697 /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */
2698 assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE));
2699 }
2700 }
2701
2702 /* Check a tree and its subtrees. */
2703 static void do_check_tree(mstate m, tchunkptr t) {
2704 tchunkptr head = 0;
2705 tchunkptr u = t;
2706 bindex_t tindex = t->index;
2707 size_t tsize = chunksize(t);
2708 bindex_t idx;
2709 compute_tree_index(tsize, idx);
2710 assert(tindex == idx);
2711 assert(tsize >= MIN_LARGE_SIZE);
2712 assert(tsize >= minsize_for_tree_index(idx));
2713 assert((idx == NTREEBINS-1) || (tsize < minsize_for_tree_index((idx+1))));
2714
2715 do { /* traverse through chain of same-sized nodes */
2716 do_check_any_chunk(m, ((mchunkptr)u));
2717 assert(u->index == tindex);
2718 assert(chunksize(u) == tsize);
2719 assert(!cinuse(u));
2720 assert(!next_pinuse(u));
2721 assert(u->fd->bk == u);
2722 assert(u->bk->fd == u);
2723 if (u->parent == 0) {
2724 assert(u->child[0] == 0);
2725 assert(u->child[1] == 0);
2726 }
2727 else {
2728 assert(head == 0); /* only one node on chain has parent */
2729 head = u;
2730 assert(u->parent != u);
2731 assert (u->parent->child[0] == u ||
2732 u->parent->child[1] == u ||
2733 *((tbinptr*)(u->parent)) == u);
2734 if (u->child[0] != 0) {
2735 assert(u->child[0]->parent == u);
2736 assert(u->child[0] != u);
2737 do_check_tree(m, u->child[0]);
2738 }
2739 if (u->child[1] != 0) {
2740 assert(u->child[1]->parent == u);
2741 assert(u->child[1] != u);
2742 do_check_tree(m, u->child[1]);
2743 }
2744 if (u->child[0] != 0 && u->child[1] != 0) {
2745 assert(chunksize(u->child[0]) < chunksize(u->child[1]));
2746 }
2747 }
2748 u = u->fd;
2749 } while (u != t);
2750 assert(head != 0);
2751 }
2752
2753 /* Check all the chunks in a treebin. */
2754 static void do_check_treebin(mstate m, bindex_t i) {
2755 tbinptr* tb = treebin_at(m, i);
2756 tchunkptr t = *tb;
2757 int empty = (m->treemap & (1U << i)) == 0;
2758 if (t == 0)
2759 assert(empty);
2760 if (!empty)
2761 do_check_tree(m, t);
2762 }
2763
2764 /* Check all the chunks in a smallbin. */
2765 static void do_check_smallbin(mstate m, bindex_t i) {
2766 sbinptr b = smallbin_at(m, i);
2767 mchunkptr p = b->bk;
2768 unsigned int empty = (m->smallmap & (1U << i)) == 0;
2769 if (p == b)
2770 assert(empty);
2771 if (!empty) {
2772 for (; p != b; p = p->bk) {
2773 size_t size = chunksize(p);
2774 mchunkptr q;
2775 /* each chunk claims to be free */
2776 do_check_free_chunk(m, p);
2777 /* chunk belongs in bin */
2778 assert(small_index(size) == i);
2779 assert(p->bk == b || chunksize(p->bk) == chunksize(p));
2780 /* chunk is followed by an inuse chunk */
2781 q = next_chunk(p);
2782 if (q->head != FENCEPOST_HEAD)
2783 do_check_inuse_chunk(m, q);
2784 }
2785 }
2786 }
2787
2788 /* Find x in a bin. Used in other check functions. */
2789 static int bin_find(mstate m, mchunkptr x) {
2790 size_t size = chunksize(x);
2791 if (is_small(size)) {
2792 bindex_t sidx = small_index(size);
2793 sbinptr b = smallbin_at(m, sidx);
2794 if (smallmap_is_marked(m, sidx)) {
2795 mchunkptr p = b;
2796 do {
2797 if (p == x)
2798 return 1;
2799 } while ((p = p->fd) != b);
2800 }
2801 }
2802 else {
2803 bindex_t tidx;
2804 compute_tree_index(size, tidx);
2805 if (treemap_is_marked(m, tidx)) {
2806 tchunkptr t = *treebin_at(m, tidx);
2807 size_t sizebits = size << leftshift_for_tree_index(tidx);
2808 while (t != 0 && chunksize(t) != size) {
2809 t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
2810 sizebits <<= 1;
2811 }
2812 if (t != 0) {
2813 tchunkptr u = t;
2814 do {
2815 if (u == (tchunkptr)x)
2816 return 1;
2817 } while ((u = u->fd) != t);
2818 }
2819 }
2820 }
2821 return 0;
2822 }
2823
2824 /* Traverse each chunk and check it; return total */
2825 static size_t traverse_and_check(mstate m) {
2826 size_t sum = 0;
2827 if (is_initialized(m)) {
2828 msegmentptr s = &m->seg;
2829 sum += m->topsize + TOP_FOOT_SIZE;
2830 while (s != 0) {
2831 mchunkptr q = align_as_chunk(s->base);
2832 mchunkptr lastq = 0;
2833 assert(pinuse(q));
2834 while (segment_holds(s, q) &&
2835 q != m->top && q->head != FENCEPOST_HEAD) {
2836 sum += chunksize(q);
2837 if (cinuse(q)) {
2838 assert(!bin_find(m, q));
2839 do_check_inuse_chunk(m, q);
2840 }
2841 else {
2842 assert(q == m->dv || bin_find(m, q));
2843 assert(lastq == 0 || cinuse(lastq)); /* Not 2 consecutive free */
2844 do_check_free_chunk(m, q);
2845 }
2846 lastq = q;
2847 q = next_chunk(q);
2848 }
2849 s = s->next;
2850 }
2851 }
2852 return sum;
2853 }
2854
2855 /* Check all properties of malloc_state. */
2856 static void do_check_malloc_state(mstate m) {
2857 bindex_t i;
2858 size_t total;
2859 /* check bins */
2860 for (i = 0; i < NSMALLBINS; ++i)
2861 do_check_smallbin(m, i);
2862 for (i = 0; i < NTREEBINS; ++i)
2863 do_check_treebin(m, i);
2864
2865 if (m->dvsize != 0) { /* check dv chunk */
2866 do_check_any_chunk(m, m->dv);
2867 assert(m->dvsize == chunksize(m->dv));
2868 assert(m->dvsize >= MIN_CHUNK_SIZE);
2869 assert(bin_find(m, m->dv) == 0);
2870 }
2871
2872 if (m->top != 0) { /* check top chunk */
2873 do_check_top_chunk(m, m->top);
2874 assert(m->topsize == chunksize(m->top));
2875 assert(m->topsize > 0);
2876 assert(bin_find(m, m->top) == 0);
2877 }
2878
2879 total = traverse_and_check(m);
2880 assert(total <= m->footprint);
2881 assert(m->footprint <= m->max_footprint);
2882 }
2883 #endif /* DEBUG */
2884
2885 /* ----------------------------- statistics ------------------------------ */
2886
2887 #if !NO_MALLINFO
2888 static struct mallinfo internal_mallinfo(mstate m) {
2889 struct mallinfo nm = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
2890 if (!PREACTION(m)) {
2891 check_malloc_state(m);
2892 if (is_initialized(m)) {
2893 size_t nfree = SIZE_T_ONE; /* top always free */
2894 size_t mfree = m->topsize + TOP_FOOT_SIZE;
2895 size_t sum = mfree;
2896 msegmentptr s = &m->seg;
2897 while (s != 0) {
2898 mchunkptr q = align_as_chunk(s->base);
2899 while (segment_holds(s, q) &&
2900 q != m->top && q->head != FENCEPOST_HEAD) {
2901 size_t sz = chunksize(q);
2902 sum += sz;
2903 if (!cinuse(q)) {
2904 mfree += sz;
2905 ++nfree;
2906 }
2907 q = next_chunk(q);
2908 }
2909 s = s->next;
2910 }
2911
2912 nm.arena = sum;
2913 nm.ordblks = nfree;
2914 nm.hblkhd = m->footprint - sum;
2915 nm.usmblks = m->max_footprint;
2916 nm.uordblks = m->footprint - mfree;
2917 nm.fordblks = mfree;
2918 nm.keepcost = m->topsize;
2919 }
2920
2921 POSTACTION(m);
2922 }
2923 return nm;
2924 }
2925 #endif /* !NO_MALLINFO */
2926
2927 static void internal_malloc_stats(mstate m) {
2928 if (!PREACTION(m)) {
2929 size_t maxfp = 0;
2930 size_t fp = 0;
2931 size_t used = 0;
2932 check_malloc_state(m);
2933 if (is_initialized(m)) {
2934 msegmentptr s = &m->seg;
2935 maxfp = m->max_footprint;
2936 fp = m->footprint;
2937 used = fp - (m->topsize + TOP_FOOT_SIZE);
2938
2939 while (s != 0) {
2940 mchunkptr q = align_as_chunk(s->base);
2941 while (segment_holds(s, q) &&
2942 q != m->top && q->head != FENCEPOST_HEAD) {
2943 if (!cinuse(q))
2944 used -= chunksize(q);
2945 q = next_chunk(q);
2946 }
2947 s = s->next;
2948 }
2949 }
2950
2951 fprintf(stderr, "max system bytes = %10lu\n", (unsigned long)(maxfp));
2952 fprintf(stderr, "system bytes = %10lu\n", (unsigned long)(fp));
2953 fprintf(stderr, "in use bytes = %10lu\n", (unsigned long)(used));
2954
2955 POSTACTION(m);
2956 }
2957 }
2958
2959 /* ----------------------- Operations on smallbins ----------------------- */
2960
2961 /*
2962 Various forms of linking and unlinking are defined as macros. Even
2963 the ones for trees, which are very long but have very short typical
2964 paths. This is ugly but reduces reliance on inlining support of
2965 compilers.
2966 */
2967
2968 /* Link a free chunk into a smallbin */
2969 #define insert_small_chunk(M, P, S) {\
2970 bindex_t I = small_index(S);\
2971 mchunkptr B = smallbin_at(M, I);\
2972 mchunkptr F = B;\
2973 assert(S >= MIN_CHUNK_SIZE);\
2974 if (!smallmap_is_marked(M, I))\
2975 mark_smallmap(M, I);\
2976 else if (RTCHECK(ok_address(M, B->fd)))\
2977 F = B->fd;\
2978 else {\
2979 CORRUPTION_ERROR_ACTION(M);\
2980 }\
2981 B->fd = P;\
2982 F->bk = P;\
2983 P->fd = F;\
2984 P->bk = B;\
2985 }
2986
2987 /* Unlink a chunk from a smallbin */
2988 #define unlink_small_chunk(M, P, S) {\
2989 mchunkptr F = P->fd;\
2990 mchunkptr B = P->bk;\
2991 bindex_t I = small_index(S);\
2992 assert(P != B);\
2993 assert(P != F);\
2994 assert(chunksize(P) == small_index2size(I));\
2995 if (F == B)\
2996 clear_smallmap(M, I);\
2997 else if (RTCHECK((F == smallbin_at(M,I) || ok_address(M, F)) &&\
2998 (B == smallbin_at(M,I) || ok_address(M, B)))) {\
2999 F->bk = B;\
3000 B->fd = F;\
3001 }\
3002 else {\
3003 CORRUPTION_ERROR_ACTION(M);\
3004 }\
3005 }
3006
3007 /* Unlink the first chunk from a smallbin */
3008 #define unlink_first_small_chunk(M, B, P, I) {\
3009 mchunkptr F = P->fd;\
3010 assert(P != B);\
3011 assert(P != F);\
3012 assert(chunksize(P) == small_index2size(I));\
3013 if (B == F)\
3014 clear_smallmap(M, I);\
3015 else if (RTCHECK(ok_address(M, F))) {\
3016 B->fd = F;\
3017 F->bk = B;\
3018 }\
3019 else {\
3020 CORRUPTION_ERROR_ACTION(M);\
3021 }\
3022 }
3023
3024 /* Replace dv node, binning the old one */
3025 /* Used only when dvsize known to be small */
3026 #define replace_dv(M, P, S) {\
3027 size_t DVS = M->dvsize;\
3028 if (DVS != 0) {\
3029 mchunkptr DV = M->dv;\
3030 assert(is_small(DVS));\
3031 insert_small_chunk(M, DV, DVS);\
3032 }\
3033 M->dvsize = S;\
3034 M->dv = P;\
3035 }
3036
3037 /* ------------------------- Operations on trees ------------------------- */
3038
3039 /* Insert chunk into tree */
3040 #define insert_large_chunk(M, X, S) {\
3041 tbinptr* H;\
3042 bindex_t I;\
3043 compute_tree_index(S, I);\
3044 H = treebin_at(M, I);\
3045 X->index = I;\
3046 X->child[0] = X->child[1] = 0;\
3047 if (!treemap_is_marked(M, I)) {\
3048 mark_treemap(M, I);\
3049 *H = X;\
3050 X->parent = (tchunkptr)H;\
3051 X->fd = X->bk = X;\
3052 }\
3053 else {\
3054 tchunkptr T = *H;\
3055 size_t K = S << leftshift_for_tree_index(I);\
3056 for (;;) {\
3057 if (chunksize(T) != S) {\
3058 tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\
3059 K <<= 1;\
3060 if (*C != 0)\
3061 T = *C;\
3062 else if (RTCHECK(ok_address(M, C))) {\
3063 *C = X;\
3064 X->parent = T;\
3065 X->fd = X->bk = X;\
3066 break;\
3067 }\
3068 else {\
3069 CORRUPTION_ERROR_ACTION(M);\
3070 break;\
3071 }\
3072 }\
3073 else {\
3074 tchunkptr F = T->fd;\
3075 if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\
3076 T->fd = F->bk = X;\
3077 X->fd = F;\
3078 X->bk = T;\
3079 X->parent = 0;\
3080 break;\
3081 }\
3082 else {\
3083 CORRUPTION_ERROR_ACTION(M);\
3084 break;\
3085 }\
3086 }\
3087 }\
3088 }\
3089 }
3090
3091 /*
3092 Unlink steps:
3093
3094 1. If x is a chained node, unlink it from its same-sized fd/bk links
3095 and choose its bk node as its replacement.
3096 2. If x was the last node of its size, but not a leaf node, it must
3097 be replaced with a leaf node (not merely one with an open left or
3098 right), to make sure that lefts and rights of descendants
3099 correspond properly to bit masks. We use the rightmost descendant
3100 of x. We could use any other leaf, but this is easy to locate and
3101 tends to counteract removal of leftmosts elsewhere, and so keeps
3102 paths shorter than minimally guaranteed. This doesn't loop much
3103 because on average a node in a tree is near the bottom.
3104 3. If x is the base of a chain (i.e., has parent links) relink
3105 x's parent and children to x's replacement (or null if none).
3106 */
3107
3108 #define unlink_large_chunk(M, X) {\
3109 tchunkptr XP = X->parent;\
3110 tchunkptr R;\
3111 if (X->bk != X) {\
3112 tchunkptr F = X->fd;\
3113 R = X->bk;\
3114 if (RTCHECK(ok_address(M, F))) {\
3115 F->bk = R;\
3116 R->fd = F;\
3117 }\
3118 else {\
3119 CORRUPTION_ERROR_ACTION(M);\
3120 }\
3121 }\
3122 else {\
3123 tchunkptr* RP;\
3124 if (((R = *(RP = &(X->child[1]))) != 0) ||\
3125 ((R = *(RP = &(X->child[0]))) != 0)) {\
3126 tchunkptr* CP;\
3127 while ((*(CP = &(R->child[1])) != 0) ||\
3128 (*(CP = &(R->child[0])) != 0)) {\
3129 R = *(RP = CP);\
3130 }\
3131 if (RTCHECK(ok_address(M, RP)))\
3132 *RP = 0;\
3133 else {\
3134 CORRUPTION_ERROR_ACTION(M);\
3135 }\
3136 }\
3137 }\
3138 if (XP != 0) {\
3139 tbinptr* H = treebin_at(M, X->index);\
3140 if (X == *H) {\
3141 if ((*H = R) == 0) \
3142 clear_treemap(M, X->index);\
3143 }\
3144 else if (RTCHECK(ok_address(M, XP))) {\
3145 if (XP->child[0] == X) \
3146 XP->child[0] = R;\
3147 else \
3148 XP->child[1] = R;\
3149 }\
3150 else\
3151 CORRUPTION_ERROR_ACTION(M);\
3152 if (R != 0) {\
3153 if (RTCHECK(ok_address(M, R))) {\
3154 tchunkptr C0, C1;\
3155 R->parent = XP;\
3156 if ((C0 = X->child[0]) != 0) {\
3157 if (RTCHECK(ok_address(M, C0))) {\
3158 R->child[0] = C0;\
3159 C0->parent = R;\
3160 }\
3161 else\
3162 CORRUPTION_ERROR_ACTION(M);\
3163 }\
3164 if ((C1 = X->child[1]) != 0) {\
3165 if (RTCHECK(ok_address(M, C1))) {\
3166 R->child[1] = C1;\
3167 C1->parent = R;\
3168 }\
3169 else\
3170 CORRUPTION_ERROR_ACTION(M);\
3171 }\
3172 }\
3173 else\
3174 CORRUPTION_ERROR_ACTION(M);\
3175 }\
3176 }\
3177 }
3178
3179 /* Relays to large vs small bin operations */
3180
3181 #define insert_chunk(M, P, S)\
3182 if (is_small(S)) insert_small_chunk(M, P, S)\
3183 else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); }
3184
3185 #define unlink_chunk(M, P, S)\
3186 if (is_small(S)) unlink_small_chunk(M, P, S)\
3187 else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); }
3188
3189
3190 /* Relays to internal calls to malloc/free from realloc, memalign etc */
3191
3192 #if ONLY_MSPACES
3193 #define internal_malloc(m, b) mspace_malloc(m, b)
3194 #define internal_free(m, mem) mspace_free(m,mem);
3195 #else /* ONLY_MSPACES */
3196 #if MSPACES
3197 #define internal_malloc(m, b)\
3198 (m == gm)? dlmalloc(b) : mspace_malloc(m, b)
3199 #define internal_free(m, mem)\
3200 if (m == gm) dlfree(mem); else mspace_free(m,mem);
3201 #else /* MSPACES */
3202 #define internal_malloc(m, b) dlmalloc(b)
3203 #define internal_free(m, mem) dlfree(mem)
3204 #endif /* MSPACES */
3205 #endif /* ONLY_MSPACES */
3206
3207 /* ----------------------- Direct-mmapping chunks ----------------------- */
3208
3209 /*
3210 Directly mmapped chunks are set up with an offset to the start of
3211 the mmapped region stored in the prev_foot field of the chunk. This
3212 allows reconstruction of the required argument to MUNMAP when freed,
3213 and also allows adjustment of the returned chunk to meet alignment
3214 requirements (especially in memalign). There is also enough space
3215 allocated to hold a fake next chunk of size SIZE_T_SIZE to maintain
3216 the PINUSE bit so frees can be checked.
3217 */
3218
3219 /* Malloc using mmap */
3220 static void* mmap_alloc(mstate m, size_t nb) {
3221 size_t mmsize = granularity_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
3222 if (mmsize > nb) { /* Check for wrap around 0 */
3223 char* mm = (char*)(DIRECT_MMAP(mmsize));
3224 if (mm != CMFAIL) {
3225 size_t offset = align_offset(chunk2mem(mm));
3226 size_t psize = mmsize - offset - MMAP_FOOT_PAD;
3227 mchunkptr p = (mchunkptr)(mm + offset);
3228 p->prev_foot = offset | IS_MMAPPED_BIT;
3229 (p)->head = (psize|CINUSE_BIT);
3230 mark_inuse_foot(m, p, psize);
3231 chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
3232 chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0;
3233
3234 if (mm < m->least_addr)
3235 m->least_addr = mm;
3236 if ((m->footprint += mmsize) > m->max_footprint)
3237 m->max_footprint = m->footprint;
3238 assert(is_aligned(chunk2mem(p)));
3239 check_mmapped_chunk(m, p);
3240 return chunk2mem(p);
3241 }
3242 }
3243 return 0;
3244 }
3245
3246 /* Realloc using mmap */
3247 static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb) {
3248 size_t oldsize = chunksize(oldp);
3249 if (is_small(nb)) /* Can't shrink mmap regions below small size */
3250 return 0;
3251 /* Keep old chunk if big enough but not too big */
3252 if (oldsize >= nb + SIZE_T_SIZE &&
3253 (oldsize - nb) <= (mparams.granularity << 1))
3254 return oldp;
3255 else {
3256 size_t offset = oldp->prev_foot & ~IS_MMAPPED_BIT;
3257 size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
3258 size_t newmmsize = granularity_align(nb + SIX_SIZE_T_SIZES +
3259 CHUNK_ALIGN_MASK);
3260 char* cp = (char*)CALL_MREMAP((char*)oldp - offset,
3261 oldmmsize, newmmsize, 1);
3262 if (cp != CMFAIL) {
3263 mchunkptr newp = (mchunkptr)(cp + offset);
3264 size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
3265 newp->head = (psize|CINUSE_BIT);
3266 mark_inuse_foot(m, newp, psize);
3267 chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
3268 chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0;
3269
3270 if (cp < m->least_addr)
3271 m->least_addr = cp;
3272 if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
3273 m->max_footprint = m->footprint;
3274 check_mmapped_chunk(m, newp);
3275 return newp;
3276 }
3277 }
3278 return 0;
3279 }
3280
3281 /* -------------------------- mspace management -------------------------- */
3282
3283 /* Initialize top chunk and its size */
3284 static void init_top(mstate m, mchunkptr p, size_t psize) {
3285 /* Ensure alignment */
3286 size_t offset = align_offset(chunk2mem(p));
3287 p = (mchunkptr)((char*)p + offset);
3288 psize -= offset;
3289
3290 m->top = p;
3291 m->topsize = psize;
3292 p->head = psize | PINUSE_BIT;
3293 /* set size of fake trailing chunk holding overhead space only once */
3294 chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE;
3295 m->trim_check = mparams.trim_threshold; /* reset on each update */
3296 }
3297
3298 /* Initialize bins for a new mstate that is otherwise zeroed out */
3299 static void init_bins(mstate m) {
3300 /* Establish circular links for smallbins */
3301 bindex_t i;
3302 for (i = 0; i < NSMALLBINS; ++i) {
3303 sbinptr bin = smallbin_at(m,i);
3304 bin->fd = bin->bk = bin;
3305 }
3306 }
3307
3308 #if PROCEED_ON_ERROR
3309
3310 /* default corruption action */
3311 static void reset_on_error(mstate m) {
3312 int i;
3313 ++malloc_corruption_error_count;
3314 /* Reinitialize fields to forget about all memory */
3315 m->smallbins = m->treebins = 0;
3316 m->dvsize = m->topsize = 0;
3317 m->seg.base = 0;
3318 m->seg.size = 0;
3319 m->seg.next = 0;
3320 m->top = m->dv = 0;
3321 for (i = 0; i < NTREEBINS; ++i)
3322 *treebin_at(m, i) = 0;
3323 init_bins(m);
3324 }
3325 #endif /* PROCEED_ON_ERROR */
3326
3327 /* Allocate chunk and prepend remainder with chunk in successor base. */
3328 static void* prepend_alloc(mstate m, char* newbase, char* oldbase,
3329 size_t nb) {
3330 mchunkptr p = align_as_chunk(newbase);
3331 mchunkptr oldfirst = align_as_chunk(oldbase);
3332 size_t psize = (char*)oldfirst - (char*)p;
3333 mchunkptr q = chunk_plus_offset(p, nb);
3334 size_t qsize = psize - nb;
3335 set_size_and_pinuse_of_inuse_chunk(m, p, nb);
3336
3337 assert((char*)oldfirst > (char*)q);
3338 assert(pinuse(oldfirst));
3339 assert(qsize >= MIN_CHUNK_SIZE);
3340
3341 /* consolidate remainder with first chunk of old base */
3342 if (oldfirst == m->top) {
3343 size_t tsize = m->topsize += qsize;
3344 m->top = q;
3345 q->head = tsize | PINUSE_BIT;
3346 check_top_chunk(m, q);
3347 }
3348 else if (oldfirst == m->dv) {
3349 size_t dsize = m->dvsize += qsize;
3350 m->dv = q;
3351 set_size_and_pinuse_of_free_chunk(q, dsize);
3352 }
3353 else {
3354 if (!cinuse(oldfirst)) {
3355 size_t nsize = chunksize(oldfirst);
3356 unlink_chunk(m, oldfirst, nsize);
3357 oldfirst = chunk_plus_offset(oldfirst, nsize);
3358 qsize += nsize;
3359 }
3360 set_free_with_pinuse(q, qsize, oldfirst);
3361 insert_chunk(m, q, qsize);
3362 check_free_chunk(m, q);
3363 }
3364
3365 check_malloced_chunk(m, chunk2mem(p), nb);
3366 return chunk2mem(p);
3367 }
3368
3369
3370 /* Add a segment to hold a new noncontiguous region */
3371 static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) {
3372 /* Determine locations and sizes of segment, fenceposts, old top */
3373 char* old_top = (char*)m->top;
3374 msegmentptr oldsp = segment_holding(m, old_top);
3375 char* old_end = oldsp->base + oldsp->size;
3376 size_t ssize = pad_request(sizeof(struct malloc_segment));
3377 char* rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
3378 size_t offset = align_offset(chunk2mem(rawsp));
3379 char* asp = rawsp + offset;
3380 char* csp = (asp < (old_top + MIN_CHUNK_SIZE))? old_top : asp;
3381 mchunkptr sp = (mchunkptr)csp;
3382 msegmentptr ss = (msegmentptr)(chunk2mem(sp));
3383 mchunkptr tnext = chunk_plus_offset(sp, ssize);
3384 mchunkptr p = tnext;
3385 int nfences = 0;
3386
3387 /* reset top to new space */
3388 init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
3389
3390 /* Set up segment record */
3391 assert(is_aligned(ss));
3392 set_size_and_pinuse_of_inuse_chunk(m, sp, ssize);
3393 *ss = m->seg; /* Push current record */
3394 m->seg.base = tbase;
3395 m->seg.size = tsize;
3396 (void)set_segment_flags(&m->seg, mmapped);
3397 m->seg.next = ss;
3398
3399 /* Insert trailing fenceposts */
3400 for (;;) {
3401 mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE);
3402 p->head = FENCEPOST_HEAD;
3403 ++nfences;
3404 if ((char*)(&(nextp->head)) < old_end)
3405 p = nextp;
3406 else
3407 break;
3408 }
3409 assert(nfences >= 2);
3410
3411 /* Insert the rest of old top into a bin as an ordinary free chunk */
3412 if (csp != old_top) {
3413 mchunkptr q = (mchunkptr)old_top;
3414 size_t psize = csp - old_top;
3415 mchunkptr tn = chunk_plus_offset(q, psize);
3416 set_free_with_pinuse(q, psize, tn);
3417 insert_chunk(m, q, psize);
3418 }
3419
3420 check_top_chunk(m, m->top);
3421 }
3422
3423 /* -------------------------- System allocation -------------------------- */
3424
3425 /* Get memory from system using MORECORE or MMAP */
3426 static void* sys_alloc(mstate m, size_t nb) {
3427 char* tbase = CMFAIL;
3428 size_t tsize = 0;
3429 flag_t mmap_flag = 0;
3430
3431 init_mparams();
3432
3433 /* Directly map large chunks */
3434 if (use_mmap(m) && nb >= mparams.mmap_threshold) {
3435 void* mem = mmap_alloc(m, nb);
3436 if (mem != 0)
3437 return mem;
3438 }
3439
3440 /*
3441 Try getting memory in any of three ways (in most-preferred to
3442 least-preferred order):
3443 1. A call to MORECORE that can normally contiguously extend memory.
3444 (disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or
3445 or main space is mmapped or a previous contiguous call failed)
3446 2. A call to MMAP new space (disabled if not HAVE_MMAP).
3447 Note that under the default settings, if MORECORE is unable to
3448 fulfill a request, and HAVE_MMAP is true, then mmap is
3449 used as a noncontiguous system allocator. This is a useful backup
3450 strategy for systems with holes in address spaces -- in this case
3451 sbrk cannot contiguously expand the heap, but mmap may be able to
3452 find space.
3453 3. A call to MORECORE that cannot usually contiguously extend memory.
3454 (disabled if not HAVE_MORECORE)
3455 */
3456
3457 if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) {
3458 char* br = CMFAIL;
3459 msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top);
3460 size_t asize = 0;
3461 ACQUIRE_MORECORE_LOCK();
3462
3463 if (ss == 0) { /* First time through or recovery */
3464 char* base = (char*)CALL_MORECORE(0);
3465 if (base != CMFAIL) {
3466 asize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
3467 /* Adjust to end on a page boundary */
3468 if (!is_page_aligned(base))
3469 asize += (page_align((size_t)base) - (size_t)base);
3470 /* Can't call MORECORE if size is negative when treated as signed */
3471 if (asize < HALF_MAX_SIZE_T &&
3472 (br = (char*)(CALL_MORECORE(asize))) == base) {
3473 tbase = base;
3474 tsize = asize;
3475 }
3476 }
3477 }
3478 else {
3479 /* Subtract out existing available top space from MORECORE request. */
3480 asize = granularity_align(nb - m->topsize + TOP_FOOT_SIZE + SIZE_T_ONE);
3481 /* Use mem here only if it did continuously extend old space */
3482 if (asize < HALF_MAX_SIZE_T &&
3483 (br = (char*)(CALL_MORECORE(asize))) == ss->base+ss->size) {
3484 tbase = br;
3485 tsize = asize;
3486 }
3487 }
3488
3489 if (tbase == CMFAIL) { /* Cope with partial failure */
3490 if (br != CMFAIL) { /* Try to use/extend the space we did get */
3491 if (asize < HALF_MAX_SIZE_T &&
3492 asize < nb + TOP_FOOT_SIZE + SIZE_T_ONE) {
3493 size_t esize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE - asize);
3494 if (esize < HALF_MAX_SIZE_T) {
3495 char* end = (char*)CALL_MORECORE(esize);
3496 if (end != CMFAIL)
3497 asize += esize;
3498 else { /* Can't use; try to release */
3499 (void)CALL_MORECORE(-asize);
3500 br = CMFAIL;
3501 }
3502 }
3503 }
3504 }
3505 if (br != CMFAIL) { /* Use the space we did get */
3506 tbase = br;
3507 tsize = asize;
3508 }
3509 else
3510 disable_contiguous(m); /* Don't try contiguous path in the future */
3511 }
3512
3513 RELEASE_MORECORE_LOCK();
3514 }
3515
3516 if (HAVE_MMAP && tbase == CMFAIL) { /* Try MMAP */
3517 size_t req = nb + TOP_FOOT_SIZE + SIZE_T_ONE;
3518 size_t rsize = granularity_align(req);
3519 if (rsize > nb) { /* Fail if wraps around zero */
3520 char* mp = (char*)(CALL_MMAP(rsize));
3521 if (mp != CMFAIL) {
3522 tbase = mp;
3523 tsize = rsize;
3524 mmap_flag = IS_MMAPPED_BIT;
3525 }
3526 }
3527 }
3528
3529 if (HAVE_MORECORE && tbase == CMFAIL) { /* Try noncontiguous MORECORE */
3530 size_t asize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
3531 if (asize < HALF_MAX_SIZE_T) {
3532 char* br = CMFAIL;
3533 char* end = CMFAIL;
3534 ACQUIRE_MORECORE_LOCK();
3535 br = (char*)(CALL_MORECORE(asize));
3536 end = (char*)(CALL_MORECORE(0));
3537 RELEASE_MORECORE_LOCK();
3538 if (br != CMFAIL && end != CMFAIL && br < end) {
3539 size_t ssize = end - br;
3540 if (ssize > nb + TOP_FOOT_SIZE) {
3541 tbase = br;
3542 tsize = ssize;
3543 }
3544 }
3545 }
3546 }
3547
3548 if (tbase != CMFAIL) {
3549
3550 if ((m->footprint += tsize) > m->max_footprint)
3551 m->max_footprint = m->footprint;
3552
3553 if (!is_initialized(m)) { /* first-time initialization */
3554 m->seg.base = m->least_addr = tbase;
3555 m->seg.size = tsize;
3556 (void)set_segment_flags(&m->seg, mmap_flag);
3557 m->magic = mparams.magic;
3558 init_bins(m);
3559 if (is_global(m))
3560 init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
3561 else {
3562 /* Offset top by embedded malloc_state */
3563 mchunkptr mn = next_chunk(mem2chunk(m));
3564 init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) -TOP_FOOT_SIZE);
3565 }
3566 }
3567
3568 else {
3569 /* Try to merge with an existing segment */
3570 msegmentptr sp = &m->seg;
3571 while (sp != 0 && tbase != sp->base + sp->size)
3572 sp = sp->next;
3573 if (sp != 0 &&
3574 !is_extern_segment(sp) &&
3575 check_segment_merge(sp, tbase, tsize) &&
3576 (get_segment_flags(sp) & IS_MMAPPED_BIT) == mmap_flag &&
3577 segment_holds(sp, m->top)) { /* append */
3578 sp->size += tsize;
3579 init_top(m, m->top, m->topsize + tsize);
3580 }
3581 else {
3582 if (tbase < m->least_addr)
3583 m->least_addr = tbase;
3584 sp = &m->seg;
3585 while (sp != 0 && sp->base != tbase + tsize)
3586 sp = sp->next;
3587 if (sp != 0 &&
3588 !is_extern_segment(sp) &&
3589 check_segment_merge(sp, tbase, tsize) &&
3590 (get_segment_flags(sp) & IS_MMAPPED_BIT) == mmap_flag) {
3591 char* oldbase = sp->base;
3592 sp->base = tbase;
3593 sp->size += tsize;
3594 return prepend_alloc(m, tbase, oldbase, nb);
3595 }
3596 else
3597 add_segment(m, tbase, tsize, mmap_flag);
3598 }
3599 }
3600
3601 if (nb < m->topsize) { /* Allocate from new or extended top space */
3602 size_t rsize = m->topsize -= nb;
3603 mchunkptr p = m->top;
3604 mchunkptr r = m->top = chunk_plus_offset(p, nb);
3605 r->head = rsize | PINUSE_BIT;
3606 set_size_and_pinuse_of_inuse_chunk(m, p, nb);
3607 check_top_chunk(m, m->top);
3608 check_malloced_chunk(m, chunk2mem(p), nb);
3609 return chunk2mem(p);
3610 }
3611 }
3612
3613 MALLOC_FAILURE_ACTION;
3614 return 0;
3615 }
3616
3617 /* ----------------------- system deallocation -------------------------- */
3618
3619 /* Unmap and unlink any mmapped segments that don't contain used chunks */
3620 static size_t release_unused_segments(mstate m) {
3621 size_t released = 0;
3622 msegmentptr pred = &m->seg;
3623 msegmentptr sp = pred->next;
3624 while (sp != 0) {
3625 char* base = sp->base;
3626 size_t size = sp->size;
3627 msegmentptr next = sp->next;
3628 if (is_mmapped_segment(sp) && !is_extern_segment(sp)) {
3629 mchunkptr p = align_as_chunk(base);
3630 size_t psize = chunksize(p);
3631 /* Can unmap if first chunk holds entire segment and not pinned */
3632 if (!cinuse(p) && (char*)p + psize >= base + size - TOP_FOOT_SIZE) {
3633 tchunkptr tp = (tchunkptr)p;
3634 assert(segment_holds(sp, (char*)sp));
3635 if (p == m->dv) {
3636 m->dv = 0;
3637 m->dvsize = 0;
3638 }
3639 else {
3640 unlink_large_chunk(m, tp);
3641 }
3642 if (CALL_MUNMAP(base, size) == 0) {
3643 released += size;
3644 m->footprint -= size;
3645 /* unlink obsoleted record */
3646 sp = pred;
3647 sp->next = next;
3648 }
3649 else { /* back out if cannot unmap */
3650 insert_large_chunk(m, tp, psize);
3651 }
3652 }
3653 }
3654 pred = sp;
3655 sp = next;
3656 }
3657 return released;
3658 }
3659
3660 static int sys_trim(mstate m, size_t pad) {
3661 size_t released = 0;
3662 if (pad < MAX_REQUEST && is_initialized(m)) {
3663 pad += TOP_FOOT_SIZE; /* ensure enough room for segment overhead */
3664
3665 if (m->topsize > pad) {
3666 /* Shrink top space in granularity-size units, keeping at least one */
3667 size_t unit = mparams.granularity;
3668 size_t extra = ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit -
3669 SIZE_T_ONE) * unit;
3670 msegmentptr sp = segment_holding(m, (char*)m->top);
3671
3672 if (!is_extern_segment(sp)) {
3673 if (is_mmapped_segment(sp)) {
3674 if (HAVE_MMAP &&
3675 sp->size >= extra &&
3676 !has_segment_link(m, sp)) { /* can't shrink if pinned */
3677 size_t newsize = sp->size - extra;
3678 /* Prefer mremap, fall back to munmap */
3679 if ((CALL_MREMAP(sp->base, sp->size, newsize, 0) != MFAIL) ||
3680 (CALL_MUNMAP(sp->base + newsize, extra) == 0)) {
3681 released = extra;
3682 }
3683 }
3684 }
3685 else if (HAVE_MORECORE) {
3686 if (extra >= HALF_MAX_SIZE_T) /* Avoid wrapping negative */
3687 extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit;
3688 ACQUIRE_MORECORE_LOCK();
3689 {
3690 /* Make sure end of memory is where we last set it. */
3691 char* old_br = (char*)(CALL_MORECORE(0));
3692 if (old_br == sp->base + sp->size) {
3693 char* rel_br = (char*)(CALL_MORECORE(-extra));
3694 char* new_br = (char*)(CALL_MORECORE(0));
3695 if (rel_br != CMFAIL && new_br < old_br)
3696 released = old_br - new_br;
3697 }
3698 }
3699 RELEASE_MORECORE_LOCK();
3700 }
3701 }
3702
3703 if (released != 0) {
3704 sp->size -= released;
3705 m->footprint -= released;
3706 init_top(m, m->top, m->topsize - released);
3707 check_top_chunk(m, m->top);
3708 }
3709 }
3710
3711 /* Unmap any unused mmapped segments */
3712 if (HAVE_MMAP)
3713 released += release_unused_segments(m);
3714
3715 /* On failure, disable autotrim to avoid repeated failed future calls */
3716 if (released == 0)
3717 m->trim_check = MAX_SIZE_T;
3718 }
3719
3720 return (released != 0)? 1 : 0;
3721 }
3722
3723 /* ---------------------------- malloc support --------------------------- */
3724
3725 /* allocate a large request from the best fitting chunk in a treebin */
3726 static void* tmalloc_large(mstate m, size_t nb) {
3727 tchunkptr v = 0;
3728 size_t rsize = -nb; /* Unsigned negation */
3729 tchunkptr t;
3730 bindex_t idx;
3731 compute_tree_index(nb, idx);
3732
3733 if ((t = *treebin_at(m, idx)) != 0) {
3734 /* Traverse tree for this bin looking for node with size == nb */
3735 size_t sizebits = nb << leftshift_for_tree_index(idx);
3736 tchunkptr rst = 0; /* The deepest untaken right subtree */
3737 for (;;) {
3738 tchunkptr rt;
3739 size_t trem = chunksize(t) - nb;
3740 if (trem < rsize) {
3741 v = t;
3742 if ((rsize = trem) == 0)
3743 break;
3744 }
3745 rt = t->child[1];
3746 t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
3747 if (rt != 0 && rt != t)
3748 rst = rt;
3749 if (t == 0) {
3750 t = rst; /* set t to least subtree holding sizes > nb */
3751 break;
3752 }
3753 sizebits <<= 1;
3754 }
3755 }
3756
3757 if (t == 0 && v == 0) { /* set t to root of next non-empty treebin */
3758 binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap;
3759 if (leftbits != 0) {
3760 bindex_t i;
3761 binmap_t leastbit = least_bit(leftbits);
3762 compute_bit2idx(leastbit, i);
3763 t = *treebin_at(m, i);
3764 }
3765 }
3766
3767 while (t != 0) { /* find smallest of tree or subtree */
3768 size_t trem = chunksize(t) - nb;
3769 if (trem < rsize) {
3770 rsize = trem;
3771 v = t;
3772 }
3773 t = leftmost_child(t);
3774 }
3775
3776 /* If dv is a better fit, return 0 so malloc will use it */
3777 if (v != 0 && rsize < (size_t)(m->dvsize - nb)) {
3778 if (RTCHECK(ok_address(m, v))) { /* split */
3779 mchunkptr r = chunk_plus_offset(v, nb);
3780 assert(chunksize(v) == rsize + nb);
3781 if (RTCHECK(ok_next(v, r))) {
3782 unlink_large_chunk(m, v);
3783 if (rsize < MIN_CHUNK_SIZE)
3784 set_inuse_and_pinuse(m, v, (rsize + nb));
3785 else {
3786 set_size_and_pinuse_of_inuse_chunk(m, v, nb);
3787 set_size_and_pinuse_of_free_chunk(r, rsize);
3788 insert_chunk(m, r, rsize);
3789 }
3790 return chunk2mem(v);
3791 }
3792 }
3793 CORRUPTION_ERROR_ACTION(m);
3794 }
3795 return 0;
3796 }
3797
3798 /* allocate a small request from the best fitting chunk in a treebin */
3799 static void* tmalloc_small(mstate m, size_t nb) {
3800 tchunkptr t, v;
3801 size_t rsize;
3802 bindex_t i;
3803 binmap_t leastbit = least_bit(m->treemap);
3804 compute_bit2idx(leastbit, i);
3805
3806 v = t = *treebin_at(m, i);
3807 rsize = chunksize(t) - nb;
3808
3809 while ((t = leftmost_child(t)) != 0) {
3810 size_t trem = chunksize(t) - nb;
3811 if (trem < rsize) {
3812 rsize = trem;
3813 v = t;
3814 }
3815 }
3816
3817 if (RTCHECK(ok_address(m, v))) {
3818 mchunkptr r = chunk_plus_offset(v, nb);
3819 assert(chunksize(v) == rsize + nb);
3820 if (RTCHECK(ok_next(v, r))) {
3821 unlink_large_chunk(m, v);
3822 if (rsize < MIN_CHUNK_SIZE)
3823 set_inuse_and_pinuse(m, v, (rsize + nb));
3824 else {
3825 set_size_and_pinuse_of_inuse_chunk(m, v, nb);
3826 set_size_and_pinuse_of_free_chunk(r, rsize);
3827 replace_dv(m, r, rsize);
3828 }
3829 return chunk2mem(v);
3830 }
3831 }
3832
3833 CORRUPTION_ERROR_ACTION(m);
3834 return 0;
3835 }
3836
3837 /* --------------------------- realloc support --------------------------- */
3838
3839 static void* internal_realloc(mstate m, void* oldmem, size_t bytes) {
3840 if (bytes >= MAX_REQUEST) {
3841 MALLOC_FAILURE_ACTION;
3842 return 0;
3843 }
3844 if (!PREACTION(m)) {
3845 mchunkptr oldp = mem2chunk(oldmem);
3846 size_t oldsize = chunksize(oldp);
3847 mchunkptr next = chunk_plus_offset(oldp, oldsize);
3848 mchunkptr newp = 0;
3849 void* extra = 0;
3850
3851 /* Try to either shrink or extend into top. Else malloc-copy-free */
3852
3853 if (RTCHECK(ok_address(m, oldp) && ok_cinuse(oldp) &&
3854 ok_next(oldp, next) && ok_pinuse(next))) {
3855 size_t nb = request2size(bytes);
3856 if (is_mmapped(oldp))
3857 newp = mmap_resize(m, oldp, nb);
3858 else if (oldsize >= nb) { /* already big enough */
3859 size_t rsize = oldsize - nb;
3860 newp = oldp;
3861 if (rsize >= MIN_CHUNK_SIZE) {
3862 mchunkptr remainder = chunk_plus_offset(newp, nb);
3863 set_inuse(m, newp, nb);
3864 set_inuse(m, remainder, rsize);
3865 extra = chunk2mem(remainder);
3866 }
3867 }
3868 else if (next == m->top && oldsize + m->topsize > nb) {
3869 /* Expand into top */
3870 size_t newsize = oldsize + m->topsize;
3871 size_t newtopsize = newsize - nb;
3872 mchunkptr newtop = chunk_plus_offset(oldp, nb);
3873 set_inuse(m, oldp, nb);
3874 newtop->head = newtopsize |PINUSE_BIT;
3875 m->top = newtop;
3876 m->topsize = newtopsize;
3877 newp = oldp;
3878 }
3879 }
3880 else {
3881 USAGE_ERROR_ACTION(m, oldmem);
3882 POSTACTION(m);
3883 return 0;
3884 }
3885
3886 POSTACTION(m);
3887
3888 if (newp != 0) {
3889 if (extra != 0) {
3890 internal_free(m, extra);
3891 }
3892 check_inuse_chunk(m, newp);
3893 return chunk2mem(newp);
3894 }
3895 else {
3896 void* newmem = internal_malloc(m, bytes);
3897 if (newmem != 0) {
3898 size_t oc = oldsize - overhead_for(oldp);
3899 memcpy(newmem, oldmem, (oc < bytes)? oc : bytes);
3900 internal_free(m, oldmem);
3901 }
3902 return newmem;
3903 }
3904 }
3905 return 0;
3906 }
3907
3908 /* --------------------------- memalign support -------------------------- */
3909
3910 static void* internal_memalign(mstate m, size_t alignment, size_t bytes) {
3911 if (alignment <= MALLOC_ALIGNMENT) /* Can just use malloc */
3912 return internal_malloc(m, bytes);
3913 if (alignment < MIN_CHUNK_SIZE) /* must be at least a minimum chunk size */
3914 alignment = MIN_CHUNK_SIZE;
3915 if ((alignment & (alignment-SIZE_T_ONE)) != 0) {/* Ensure a power of 2 */
3916 size_t a = MALLOC_ALIGNMENT << 1;
3917 while (a < alignment) a <<= 1;
3918 alignment = a;
3919 }
3920
3921 if (bytes >= MAX_REQUEST - alignment) {
3922 if (m != 0) { /* Test isn't needed but avoids compiler warning */
3923 MALLOC_FAILURE_ACTION;
3924 }
3925 }
3926 else {
3927 size_t nb = request2size(bytes);
3928 size_t req = nb + alignment + MIN_CHUNK_SIZE - CHUNK_OVERHEAD;
3929 char* mem = (char*)internal_malloc(m, req);
3930 if (mem != 0) {
3931 void* leader = 0;
3932 void* trailer = 0;
3933 mchunkptr p = mem2chunk(mem);
3934
3935 if (PREACTION(m)) return 0;
3936 if ((((size_t)(mem)) % alignment) != 0) { /* misaligned */
3937 /*
3938 Find an aligned spot inside chunk. Since we need to give
3939 back leading space in a chunk of at least MIN_CHUNK_SIZE, if
3940 the first calculation places us at a spot with less than
3941 MIN_CHUNK_SIZE leader, we can move to the next aligned spot.
3942 We've allocated enough total room so that this is always
3943 possible.
3944 */
3945 char* br = (char*)mem2chunk((size_t)(((size_t)(mem +
3946 alignment -
3947 SIZE_T_ONE)) &
3948 -alignment));
3949 char* pos = ((size_t)(br - (char*)(p)) >= MIN_CHUNK_SIZE)?
3950 br : br+alignment;
3951 mchunkptr newp = (mchunkptr)pos;
3952 size_t leadsize = pos - (char*)(p);
3953 size_t newsize = chunksize(p) - leadsize;
3954
3955 if (is_mmapped(p)) { /* For mmapped chunks, just adjust offset */
3956 newp->prev_foot = p->prev_foot + leadsize;
3957 newp->head = (newsize|CINUSE_BIT);
3958 }
3959 else { /* Otherwise, give back leader, use the rest */
3960 set_inuse(m, newp, newsize);
3961 set_inuse(m, p, leadsize);
3962 leader = chunk2mem(p);
3963 }
3964 p = newp;
3965 }
3966
3967 /* Give back spare room at the end */
3968 if (!is_mmapped(p)) {
3969 size_t size = chunksize(p);
3970 if (size > nb + MIN_CHUNK_SIZE) {
3971 size_t remainder_size = size - nb;
3972 mchunkptr remainder = chunk_plus_offset(p, nb);
3973 set_inuse(m, p, nb);
3974 set_inuse(m, remainder, remainder_size);
3975 trailer = chunk2mem(remainder);
3976 }
3977 }
3978
3979 assert (chunksize(p) >= nb);
3980 assert((((size_t)(chunk2mem(p))) % alignment) == 0);
3981 check_inuse_chunk(m, p);
3982 POSTACTION(m);
3983 if (leader != 0) {
3984 internal_free(m, leader);
3985 }
3986 if (trailer != 0) {
3987 internal_free(m, trailer);
3988 }
3989 return chunk2mem(p);
3990 }
3991 }
3992 return 0;
3993 }
3994
3995 /* ------------------------ comalloc/coalloc support --------------------- */
3996
3997 static void** ialloc(mstate m,
3998 size_t n_elements,
3999 size_t* sizes,
4000 int opts,
4001 void* chunks[]) {
4002 /*
4003 This provides common support for independent_X routines, handling
4004 all of the combinations that can result.
4005
4006 The opts arg has:
4007 bit 0 set if all elements are same size (using sizes[0])
4008 bit 1 set if elements should be zeroed
4009 */
4010
4011 size_t element_size; /* chunksize of each element, if all same */
4012 size_t contents_size; /* total size of elements */
4013 size_t array_size; /* request size of pointer array */
4014 void* mem; /* malloced aggregate space */
4015 mchunkptr p; /* corresponding chunk */
4016 size_t remainder_size; /* remaining bytes while splitting */
4017 void** marray; /* either "chunks" or malloced ptr array */
4018 mchunkptr array_chunk; /* chunk for malloced ptr array */
4019 flag_t was_enabled; /* to disable mmap */
4020 size_t size;
4021 size_t i;
4022
4023 /* compute array length, if needed */
4024 if (chunks != 0) {
4025 if (n_elements == 0)
4026 return chunks; /* nothing to do */
4027 marray = chunks;
4028 array_size = 0;
4029 }
4030 else {
4031 /* if empty req, must still return chunk representing empty array */
4032 if (n_elements == 0)
4033 return (void**)internal_malloc(m, 0);
4034 marray = 0;
4035 array_size = request2size(n_elements * (sizeof(void*)));
4036 }
4037
4038 /* compute total element size */
4039 if (opts & 0x1) { /* all-same-size */
4040 element_size = request2size(*sizes);
4041 contents_size = n_elements * element_size;
4042 }
4043 else { /* add up all the sizes */
4044 element_size = 0;
4045 contents_size = 0;
4046 for (i = 0; i != n_elements; ++i)
4047 contents_size += request2size(sizes[i]);
4048 }
4049
4050 size = contents_size + array_size;
4051
4052 /*
4053 Allocate the aggregate chunk. First disable direct-mmapping so
4054 malloc won't use it, since we would not be able to later
4055 free/realloc space internal to a segregated mmap region.
4056 */
4057 was_enabled = use_mmap(m);
4058 disable_mmap(m);
4059 mem = internal_malloc(m, size - CHUNK_OVERHEAD);
4060 if (was_enabled)
4061 enable_mmap(m);
4062 if (mem == 0)
4063 return 0;
4064
4065 if (PREACTION(m)) return 0;
4066 p = mem2chunk(mem);
4067 remainder_size = chunksize(p);
4068
4069 assert(!is_mmapped(p));
4070
4071 if (opts & 0x2) { /* optionally clear the elements */
4072 memset((size_t*)mem, 0, remainder_size - SIZE_T_SIZE - array_size);
4073 }
4074
4075 /* If not provided, allocate the pointer array as final part of chunk */
4076 if (marray == 0) {
4077 size_t array_chunk_size;
4078 array_chunk = chunk_plus_offset(p, contents_size);
4079 array_chunk_size = remainder_size - contents_size;
4080 marray = (void**) (chunk2mem(array_chunk));
4081 set_size_and_pinuse_of_inuse_chunk(m, array_chunk, array_chunk_size);
4082 remainder_size = contents_size;
4083 }
4084
4085 /* split out elements */
4086 for (i = 0; ; ++i) {
4087 marray[i] = chunk2mem(p);
4088 if (i != n_elements-1) {
4089 if (element_size != 0)
4090 size = element_size;
4091 else
4092 size = request2size(sizes[i]);
4093 remainder_size -= size;
4094 set_size_and_pinuse_of_inuse_chunk(m, p, size);
4095 p = chunk_plus_offset(p, size);
4096 }
4097 else { /* the final element absorbs any overallocation slop */
4098 set_size_and_pinuse_of_inuse_chunk(m, p, remainder_size);
4099 break;
4100 }
4101 }
4102
4103 #if DEBUG
4104 if (marray != chunks) {
4105 /* final element must have exactly exhausted chunk */
4106 if (element_size != 0) {
4107 assert(remainder_size == element_size);
4108 }
4109 else {
4110 assert(remainder_size == request2size(sizes[i]));
4111 }
4112 check_inuse_chunk(m, mem2chunk(marray));
4113 }
4114 for (i = 0; i != n_elements; ++i)
4115 check_inuse_chunk(m, mem2chunk(marray[i]));
4116
4117 #endif /* DEBUG */
4118
4119 POSTACTION(m);
4120 return marray;
4121 }
4122
4123
4124 /* -------------------------- public routines ---------------------------- */
4125
4126 #if !ONLY_MSPACES
4127
4128 void* dlmalloc(size_t bytes) {
4129 /*
4130 Basic algorithm:
4131 If a small request (< 256 bytes minus per-chunk overhead):
4132 1. If one exists, use a remainderless chunk in associated smallbin.
4133 (Remainderless means that there are too few excess bytes to
4134 represent as a chunk.)
4135 2. If it is big enough, use the dv chunk, which is normally the
4136 chunk adjacent to the one used for the most recent small request.
4137 3. If one exists, split the smallest available chunk in a bin,
4138 saving remainder in dv.
4139 4. If it is big enough, use the top chunk.
4140 5. If available, get memory from system and use it
4141 Otherwise, for a large request:
4142 1. Find the smallest available binned chunk that fits, and use it
4143 if it is better fitting than dv chunk, splitting if necessary.
4144 2. If better fitting than any binned chunk, use the dv chunk.
4145 3. If it is big enough, use the top chunk.
4146 4. If request size >= mmap threshold, try to directly mmap this chunk.
4147 5. If available, get memory from system and use it
4148
4149 The ugly goto's here ensure that postaction occurs along all paths.
4150 */
4151
4152 if (!PREACTION(gm)) {
4153 void* mem;
4154 size_t nb;
4155 if (bytes <= MAX_SMALL_REQUEST) {
4156 bindex_t idx;
4157 binmap_t smallbits;
4158 nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
4159 idx = small_index(nb);
4160 smallbits = gm->smallmap >> idx;
4161
4162 if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
4163 mchunkptr b, p;
4164 idx += ~smallbits & 1; /* Uses next bin if idx empty */
4165 b = smallbin_at(gm, idx);
4166 p = b->fd;
4167 assert(chunksize(p) == small_index2size(idx));
4168 unlink_first_small_chunk(gm, b, p, idx);
4169 set_inuse_and_pinuse(gm, p, small_index2size(idx));
4170 mem = chunk2mem(p);
4171 check_malloced_chunk(gm, mem, nb);
4172 goto postaction;
4173 }
4174
4175 else if (nb > gm->dvsize) {
4176 if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
4177 mchunkptr b, p, r;
4178 size_t rsize;
4179 bindex_t i;
4180 binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
4181 binmap_t leastbit = least_bit(leftbits);
4182 compute_bit2idx(leastbit, i);
4183 b = smallbin_at(gm, i);
4184 p = b->fd;
4185 assert(chunksize(p) == small_index2size(i));
4186 unlink_first_small_chunk(gm, b, p, i);
4187 rsize = small_index2size(i) - nb;
4188 /* Fit here cannot be remainderless if 4byte sizes */
4189 if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
4190 set_inuse_and_pinuse(gm, p, small_index2size(i));
4191 else {
4192 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
4193 r = chunk_plus_offset(p, nb);
4194 set_size_and_pinuse_of_free_chunk(r, rsize);
4195 replace_dv(gm, r, rsize);
4196 }
4197 mem = chunk2mem(p);
4198 check_malloced_chunk(gm, mem, nb);
4199 goto postaction;
4200 }
4201
4202 else if (gm->treemap != 0 && (mem = tmalloc_small(gm, nb)) != 0) {
4203 check_malloced_chunk(gm, mem, nb);
4204 goto postaction;
4205 }
4206 }
4207 }
4208 else if (bytes >= MAX_REQUEST)
4209 nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
4210 else {
4211 nb = pad_request(bytes);
4212 if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) {
4213 check_malloced_chunk(gm, mem, nb);
4214 goto postaction;
4215 }
4216 }
4217
4218 if (nb <= gm->dvsize) {
4219 size_t rsize = gm->dvsize - nb;
4220 mchunkptr p = gm->dv;
4221 if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
4222 mchunkptr r = gm->dv = chunk_plus_offset(p, nb);
4223 gm->dvsize = rsize;
4224 set_size_and_pinuse_of_free_chunk(r, rsize);
4225 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
4226 }
4227 else { /* exhaust dv */
4228 size_t dvs = gm->dvsize;
4229 gm->dvsize = 0;
4230 gm->dv = 0;
4231 set_inuse_and_pinuse(gm, p, dvs);
4232 }
4233 mem = chunk2mem(p);
4234 check_malloced_chunk(gm, mem, nb);
4235 goto postaction;
4236 }
4237
4238 else if (nb < gm->topsize) { /* Split top */
4239 size_t rsize = gm->topsize -= nb;
4240 mchunkptr p = gm->top;
4241 mchunkptr r = gm->top = chunk_plus_offset(p, nb);
4242 r->head = rsize | PINUSE_BIT;
4243 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
4244 mem = chunk2mem(p);
4245 check_top_chunk(gm, gm->top);
4246 check_malloced_chunk(gm, mem, nb);
4247 goto postaction;
4248 }
4249
4250 mem = sys_alloc(gm, nb);
4251
4252 postaction:
4253 POSTACTION(gm);
4254 return mem;
4255 }
4256
4257 return 0;
4258 }
4259
4260 void dlfree(void* mem) {
4261 /*
4262 Consolidate freed chunks with preceding or succeeding bordering
4263 free chunks, if they exist, and then place in a bin. Intermixed
4264 with special cases for top, dv, mmapped chunks, and usage errors.
4265 */
4266
4267 if (mem != 0) {
4268 mchunkptr p = mem2chunk(mem);
4269 #if FOOTERS
4270 mstate fm = get_mstate_for(p);
4271 if (!ok_magic(fm)) {
4272 USAGE_ERROR_ACTION(fm, p);
4273 return;
4274 }
4275 #else /* FOOTERS */
4276 #define fm gm
4277 #endif /* FOOTERS */
4278 if (!PREACTION(fm)) {
4279 check_inuse_chunk(fm, p);
4280 if (RTCHECK(ok_address(fm, p) && ok_cinuse(p))) {
4281 size_t psize = chunksize(p);
4282 mchunkptr next = chunk_plus_offset(p, psize);
4283 if (!pinuse(p)) {
4284 size_t prevsize = p->prev_foot;
4285 if ((prevsize & IS_MMAPPED_BIT) != 0) {
4286 prevsize &= ~IS_MMAPPED_BIT;
4287 psize += prevsize + MMAP_FOOT_PAD;
4288 if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
4289 fm->footprint -= psize;
4290 goto postaction;
4291 }
4292 else {
4293 mchunkptr prev = chunk_minus_offset(p, prevsize);
4294 psize += prevsize;
4295 p = prev;
4296 if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
4297 if (p != fm->dv) {
4298 unlink_chunk(fm, p, prevsize);
4299 }
4300 else if ((next->head & INUSE_BITS) == INUSE_BITS) {
4301 fm->dvsize = psize;
4302 set_free_with_pinuse(p, psize, next);
4303 goto postaction;
4304 }
4305 }
4306 else
4307 goto erroraction;
4308 }
4309 }
4310
4311 if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
4312 if (!cinuse(next)) { /* consolidate forward */
4313 if (next == fm->top) {
4314 size_t tsize = fm->topsize += psize;
4315 fm->top = p;
4316 p->head = tsize | PINUSE_BIT;
4317 if (p == fm->dv) {
4318 fm->dv = 0;
4319 fm->dvsize = 0;
4320 }
4321 if (should_trim(fm, tsize))
4322 sys_trim(fm, 0);
4323 goto postaction;
4324 }
4325 else if (next == fm->dv) {
4326 size_t dsize = fm->dvsize += psize;
4327 fm->dv = p;
4328 set_size_and_pinuse_of_free_chunk(p, dsize);
4329 goto postaction;
4330 }
4331 else {
4332 size_t nsize = chunksize(next);
4333 psize += nsize;
4334 unlink_chunk(fm, next, nsize);
4335 set_size_and_pinuse_of_free_chunk(p, psize);
4336 if (p == fm->dv) {
4337 fm->dvsize = psize;
4338 goto postaction;
4339 }
4340 }
4341 }
4342 else
4343 set_free_with_pinuse(p, psize, next);
4344 insert_chunk(fm, p, psize);
4345 check_free_chunk(fm, p);
4346 goto postaction;
4347 }
4348 }
4349 erroraction:
4350 USAGE_ERROR_ACTION(fm, p);
4351 postaction:
4352 POSTACTION(fm);
4353 }
4354 }
4355 #if !FOOTERS
4356 #undef fm
4357 #endif /* FOOTERS */
4358 }
4359
4360 void* dlcalloc(size_t n_elements, size_t elem_size) {
4361 void* mem;
4362 size_t req = 0;
4363 if (n_elements != 0) {
4364 req = n_elements * elem_size;
4365 if (((n_elements | elem_size) & ~(size_t)0xffff) &&
4366 (req / n_elements != elem_size))
4367 req = MAX_SIZE_T; /* force downstream failure on overflow */
4368 }
4369 mem = dlmalloc(req);
4370 if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
4371 memset(mem, 0, req);
4372 return mem;
4373 }
4374
4375 void* dlrealloc(void* oldmem, size_t bytes) {
4376 if (oldmem == 0)
4377 return dlmalloc(bytes);
4378 #ifdef REALLOC_ZERO_BYTES_FREES
4379 if (bytes == 0) {
4380 dlfree(oldmem);
4381 return 0;
4382 }
4383 #endif /* REALLOC_ZERO_BYTES_FREES */
4384 else {
4385 #if ! FOOTERS
4386 mstate m = gm;
4387 #else /* FOOTERS */
4388 mstate m = get_mstate_for(mem2chunk(oldmem));
4389 if (!ok_magic(m)) {
4390 USAGE_ERROR_ACTION(m, oldmem);
4391 return 0;
4392 }
4393 #endif /* FOOTERS */
4394 return internal_realloc(m, oldmem, bytes);
4395 }
4396 }
4397
4398 void* dlmemalign(size_t alignment, size_t bytes) {
4399 return internal_memalign(gm, alignment, bytes);
4400 }
4401
4402 void** dlindependent_calloc(size_t n_elements, size_t elem_size,
4403 void* chunks[]) {
4404 size_t sz = elem_size; /* serves as 1-element array */
4405 return ialloc(gm, n_elements, &sz, 3, chunks);
4406 }
4407
4408 void** dlindependent_comalloc(size_t n_elements, size_t sizes[],
4409 void* chunks[]) {
4410 return ialloc(gm, n_elements, sizes, 0, chunks);
4411 }
4412
4413 void* dlvalloc(size_t bytes) {
4414 size_t pagesz;
4415 init_mparams();
4416 pagesz = mparams.page_size;
4417 return dlmemalign(pagesz, bytes);
4418 }
4419
4420 void* dlpvalloc(size_t bytes) {
4421 size_t pagesz;
4422 init_mparams();
4423 pagesz = mparams.page_size;
4424 return dlmemalign(pagesz, (bytes + pagesz - SIZE_T_ONE) & ~(pagesz - SIZE_T_ONE));
4425 }
4426
4427 int dlmalloc_trim(size_t pad) {
4428 int result = 0;
4429 if (!PREACTION(gm)) {
4430 result = sys_trim(gm, pad);
4431 POSTACTION(gm);
4432 }
4433 return result;
4434 }
4435
4436 size_t dlmalloc_footprint(void) {
4437 return gm->footprint;
4438 }
4439
4440 size_t dlmalloc_max_footprint(void) {
4441 return gm->max_footprint;
4442 }
4443
4444 #if !NO_MALLINFO
4445 struct mallinfo dlmallinfo(void) {
4446 return internal_mallinfo(gm);
4447 }
4448 #endif /* NO_MALLINFO */
4449
4450 void dlmalloc_stats() {
4451 internal_malloc_stats(gm);
4452 }
4453
4454 size_t dlmalloc_usable_size(void* mem) {
4455 if (mem != 0) {
4456 mchunkptr p = mem2chunk(mem);
4457 if (cinuse(p))
4458 return chunksize(p) - overhead_for(p);
4459 }
4460 return 0;
4461 }
4462
4463 int dlmallopt(int param_number, int value) {
4464 return change_mparam(param_number, value);
4465 }
4466
4467 #endif /* !ONLY_MSPACES */
4468
4469 /* ----------------------------- user mspaces ---------------------------- */
4470
4471 #if MSPACES
4472
4473 static mstate init_user_mstate(char* tbase, size_t tsize) {
4474 size_t msize = pad_request(sizeof(struct malloc_state));
4475 mchunkptr mn;
4476 mchunkptr msp = align_as_chunk(tbase);
4477 mstate m = (mstate)(chunk2mem(msp));
4478 memset(m, 0, msize);
4479 INITIAL_LOCK(&m->mutex);
4480 msp->head = (msize|PINUSE_BIT|CINUSE_BIT);
4481 m->seg.base = m->least_addr = tbase;
4482 m->seg.size = m->footprint = m->max_footprint = tsize;
4483 m->magic = mparams.magic;
4484 m->mflags = mparams.default_mflags;
4485 disable_contiguous(m);
4486 init_bins(m);
4487 mn = next_chunk(mem2chunk(m));
4488 init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) - TOP_FOOT_SIZE);
4489 check_top_chunk(m, m->top);
4490 return m;
4491 }
4492
4493 mspace create_mspace(size_t capacity, int locked) {
4494 mstate m = 0;
4495 size_t msize = pad_request(sizeof(struct malloc_state));
4496 init_mparams(); /* Ensure pagesize etc initialized */
4497
4498 if (capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
4499 size_t rs = ((capacity == 0)? mparams.granularity :
4500 (capacity + TOP_FOOT_SIZE + msize));
4501 size_t tsize = granularity_align(rs);
4502 char* tbase = (char*)(CALL_MMAP(tsize));
4503 if (tbase != CMFAIL) {
4504 m = init_user_mstate(tbase, tsize);
4505 set_segment_flags(&m->seg, IS_MMAPPED_BIT);
4506 set_lock(m, locked);
4507 }
4508 }
4509 return (mspace)m;
4510 }
4511
4512 mspace create_mspace_with_base(void* base, size_t capacity, int locked) {
4513 mstate m = 0;
4514 size_t msize = pad_request(sizeof(struct malloc_state));
4515 init_mparams(); /* Ensure pagesize etc initialized */
4516
4517 if (capacity > msize + TOP_FOOT_SIZE &&
4518 capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
4519 m = init_user_mstate((char*)base, capacity);
4520 set_segment_flags(&m->seg, EXTERN_BIT);
4521 set_lock(m, locked);
4522 }
4523 return (mspace)m;
4524 }
4525
4526 size_t destroy_mspace(mspace msp) {
4527 size_t freed = 0;
4528 mstate ms = (mstate)msp;
4529 if (ok_magic(ms)) {
4530 msegmentptr sp = &ms->seg;
4531 while (sp != 0) {
4532 char* base = sp->base;
4533 size_t size = sp->size;
4534 flag_t flag = get_segment_flags(sp);
4535 sp = sp->next;
4536 if ((flag & IS_MMAPPED_BIT) && !(flag & EXTERN_BIT) &&
4537 CALL_MUNMAP(base, size) == 0)
4538 freed += size;
4539 }
4540 }
4541 else {
4542 USAGE_ERROR_ACTION(ms,ms);
4543 }
4544 return freed;
4545 }
4546
4547 /*
4548 mspace versions of routines are near-clones of the global
4549 versions. This is not so nice but better than the alternatives.
4550 */
4551
4552
4553 void* mspace_malloc(mspace msp, size_t bytes) {
4554 mstate ms = (mstate)msp;
4555 if (!ok_magic(ms)) {
4556 USAGE_ERROR_ACTION(ms,ms);
4557 return 0;
4558 }
4559 if (!PREACTION(ms)) {
4560 void* mem;
4561 size_t nb;
4562 if (bytes <= MAX_SMALL_REQUEST) {
4563 bindex_t idx;
4564 binmap_t smallbits;
4565 nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
4566 idx = small_index(nb);
4567 smallbits = ms->smallmap >> idx;
4568
4569 if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
4570 mchunkptr b, p;
4571 idx += ~smallbits & 1; /* Uses next bin if idx empty */
4572 b = smallbin_at(ms, idx);
4573 p = b->fd;
4574 assert(chunksize(p) == small_index2size(idx));
4575 unlink_first_small_chunk(ms, b, p, idx);
4576 set_inuse_and_pinuse(ms, p, small_index2size(idx));
4577 mem = chunk2mem(p);
4578 check_malloced_chunk(ms, mem, nb);
4579 goto postaction;
4580 }
4581
4582 else if (nb > ms->dvsize) {
4583 if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
4584 mchunkptr b, p, r;
4585 size_t rsize;
4586 bindex_t i;
4587 binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
4588 binmap_t leastbit = least_bit(leftbits);
4589 compute_bit2idx(leastbit, i);
4590 b = smallbin_at(ms, i);
4591 p = b->fd;
4592 assert(chunksize(p) == small_index2size(i));
4593 unlink_first_small_chunk(ms, b, p, i);
4594 rsize = small_index2size(i) - nb;
4595 /* Fit here cannot be remainderless if 4byte sizes */
4596 if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
4597 set_inuse_and_pinuse(ms, p, small_index2size(i));
4598 else {
4599 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
4600 r = chunk_plus_offset(p, nb);
4601 set_size_and_pinuse_of_free_chunk(r, rsize);
4602 replace_dv(ms, r, rsize);
4603 }
4604 mem = chunk2mem(p);
4605 check_malloced_chunk(ms, mem, nb);
4606 goto postaction;
4607 }
4608
4609 else if (ms->treemap != 0 && (mem = tmalloc_small(ms, nb)) != 0) {
4610 check_malloced_chunk(ms, mem, nb);
4611 goto postaction;
4612 }
4613 }
4614 }
4615 else if (bytes >= MAX_REQUEST)
4616 nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
4617 else {
4618 nb = pad_request(bytes);
4619 if (ms->treemap != 0 && (mem = tmalloc_large(ms, nb)) != 0) {
4620 check_malloced_chunk(ms, mem, nb);
4621 goto postaction;
4622 }
4623 }
4624
4625 if (nb <= ms->dvsize) {
4626 size_t rsize = ms->dvsize - nb;
4627 mchunkptr p = ms->dv;
4628 if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
4629 mchunkptr r = ms->dv = chunk_plus_offset(p, nb);
4630 ms->dvsize = rsize;
4631 set_size_and_pinuse_of_free_chunk(r, rsize);
4632 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
4633 }
4634 else { /* exhaust dv */
4635 size_t dvs = ms->dvsize;
4636 ms->dvsize = 0;
4637 ms->dv = 0;
4638 set_inuse_and_pinuse(ms, p, dvs);
4639 }
4640 mem = chunk2mem(p);
4641 check_malloced_chunk(ms, mem, nb);
4642 goto postaction;
4643 }
4644
4645 else if (nb < ms->topsize) { /* Split top */
4646 size_t rsize = ms->topsize -= nb;
4647 mchunkptr p = ms->top;
4648 mchunkptr r = ms->top = chunk_plus_offset(p, nb);
4649 r->head = rsize | PINUSE_BIT;
4650 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
4651 mem = chunk2mem(p);
4652 check_top_chunk(ms, ms->top);
4653 check_malloced_chunk(ms, mem, nb);
4654 goto postaction;
4655 }
4656
4657 mem = sys_alloc(ms, nb);
4658
4659 postaction:
4660 POSTACTION(ms);
4661 return mem;
4662 }
4663
4664 return 0;
4665 }
4666
4667 void mspace_free(mspace msp, void* mem) {
4668 if (mem != 0) {
4669 mchunkptr p = mem2chunk(mem);
4670 #if FOOTERS
4671 mstate fm = get_mstate_for(p);
4672 #else /* FOOTERS */
4673 mstate fm = (mstate)msp;
4674 #endif /* FOOTERS */
4675 if (!ok_magic(fm)) {
4676 USAGE_ERROR_ACTION(fm, p);
4677 return;
4678 }
4679 if (!PREACTION(fm)) {
4680 check_inuse_chunk(fm, p);
4681 if (RTCHECK(ok_address(fm, p) && ok_cinuse(p))) {
4682 size_t psize = chunksize(p);
4683 mchunkptr next = chunk_plus_offset(p, psize);
4684 if (!pinuse(p)) {
4685 size_t prevsize = p->prev_foot;
4686 if ((prevsize & IS_MMAPPED_BIT) != 0) {
4687 prevsize &= ~IS_MMAPPED_BIT;
4688 psize += prevsize + MMAP_FOOT_PAD;
4689 if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
4690 fm->footprint -= psize;
4691 goto postaction;
4692 }
4693 else {
4694 mchunkptr prev = chunk_minus_offset(p, prevsize);
4695 psize += prevsize;
4696 p = prev;
4697 if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
4698 if (p != fm->dv) {
4699 unlink_chunk(fm, p, prevsize);
4700 }
4701 else if ((next->head & INUSE_BITS) == INUSE_BITS) {
4702 fm->dvsize = psize;
4703 set_free_with_pinuse(p, psize, next);
4704 goto postaction;
4705 }
4706 }
4707 else
4708 goto erroraction;
4709 }
4710 }
4711
4712 if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
4713 if (!cinuse(next)) { /* consolidate forward */
4714 if (next == fm->top) {
4715 size_t tsize = fm->topsize += psize;
4716 fm->top = p;
4717 p->head = tsize | PINUSE_BIT;
4718 if (p == fm->dv) {
4719 fm->dv = 0;
4720 fm->dvsize = 0;
4721 }
4722 if (should_trim(fm, tsize))
4723 sys_trim(fm, 0);
4724 goto postaction;
4725 }
4726 else if (next == fm->dv) {
4727 size_t dsize = fm->dvsize += psize;
4728 fm->dv = p;
4729 set_size_and_pinuse_of_free_chunk(p, dsize);
4730 goto postaction;
4731 }
4732 else {
4733 size_t nsize = chunksize(next);
4734 psize += nsize;
4735 unlink_chunk(fm, next, nsize);
4736 set_size_and_pinuse_of_free_chunk(p, psize);
4737 if (p == fm->dv) {
4738 fm->dvsize = psize;
4739 goto postaction;
4740 }
4741 }
4742 }
4743 else
4744 set_free_with_pinuse(p, psize, next);
4745 insert_chunk(fm, p, psize);
4746 check_free_chunk(fm, p);
4747 goto postaction;
4748 }
4749 }
4750 erroraction:
4751 USAGE_ERROR_ACTION(fm, p);
4752 postaction:
4753 POSTACTION(fm);
4754 }
4755 }
4756 }
4757
4758 void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size) {
4759 void* mem;
4760 size_t req = 0;
4761 mstate ms = (mstate)msp;
4762 if (!ok_magic(ms)) {
4763 USAGE_ERROR_ACTION(ms,ms);
4764 return 0;
4765 }
4766 if (n_elements != 0) {
4767 req = n_elements * elem_size;
4768 if (((n_elements | elem_size) & ~(size_t)0xffff) &&
4769 (req / n_elements != elem_size))
4770 req = MAX_SIZE_T; /* force downstream failure on overflow */
4771 }
4772 mem = internal_malloc(ms, req);
4773 if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
4774 memset(mem, 0, req);
4775 return mem;
4776 }
4777
4778 void* mspace_realloc(mspace msp, void* oldmem, size_t bytes) {
4779 if (oldmem == 0)
4780 return mspace_malloc(msp, bytes);
4781 #ifdef REALLOC_ZERO_BYTES_FREES
4782 if (bytes == 0) {
4783 mspace_free(msp, oldmem);
4784 return 0;
4785 }
4786 #endif /* REALLOC_ZERO_BYTES_FREES */
4787 else {
4788 #if FOOTERS
4789 mchunkptr p = mem2chunk(oldmem);
4790 mstate ms = get_mstate_for(p);
4791 #else /* FOOTERS */
4792 mstate ms = (mstate)msp;
4793 #endif /* FOOTERS */
4794 if (!ok_magic(ms)) {
4795 USAGE_ERROR_ACTION(ms,ms);
4796 return 0;
4797 }
4798 return internal_realloc(ms, oldmem, bytes);
4799 }
4800 }
4801
4802 void* mspace_memalign(mspace msp, size_t alignment, size_t bytes) {
4803 mstate ms = (mstate)msp;
4804 if (!ok_magic(ms)) {
4805 USAGE_ERROR_ACTION(ms,ms);
4806 return 0;
4807 }
4808 return internal_memalign(ms, alignment, bytes);
4809 }
4810
4811 void** mspace_independent_calloc(mspace msp, size_t n_elements,
4812 size_t elem_size, void* chunks[]) {
4813 size_t sz = elem_size; /* serves as 1-element array */
4814 mstate ms = (mstate)msp;
4815 if (!ok_magic(ms)) {
4816 USAGE_ERROR_ACTION(ms,ms);
4817 return 0;
4818 }
4819 return ialloc(ms, n_elements, &sz, 3, chunks);
4820 }
4821
4822 void** mspace_independent_comalloc(mspace msp, size_t n_elements,
4823 size_t sizes[], void* chunks[]) {
4824 mstate ms = (mstate)msp;
4825 if (!ok_magic(ms)) {
4826 USAGE_ERROR_ACTION(ms,ms);
4827 return 0;
4828 }
4829 return ialloc(ms, n_elements, sizes, 0, chunks);
4830 }
4831
4832 int mspace_trim(mspace msp, size_t pad) {
4833 int result = 0;
4834 mstate ms = (mstate)msp;
4835 if (ok_magic(ms)) {
4836 if (!PREACTION(ms)) {
4837 result = sys_trim(ms, pad);
4838 POSTACTION(ms);
4839 }
4840 }
4841 else {
4842 USAGE_ERROR_ACTION(ms,ms);
4843 }
4844 return result;
4845 }
4846
4847 void mspace_malloc_stats(mspace msp) {
4848 mstate ms = (mstate)msp;
4849 if (ok_magic(ms)) {
4850 internal_malloc_stats(ms);
4851 }
4852 else {
4853 USAGE_ERROR_ACTION(ms,ms);
4854 }
4855 }
4856
4857 size_t mspace_footprint(mspace msp) {
4858 size_t result;
4859 mstate ms = (mstate)msp;
4860 if (ok_magic(ms)) {
4861 result = ms->footprint;
4862 }
4863 USAGE_ERROR_ACTION(ms,ms);
4864 return result;
4865 }
4866
4867
4868 size_t mspace_max_footprint(mspace msp) {
4869 size_t result;
4870 mstate ms = (mstate)msp;
4871 if (ok_magic(ms)) {
4872 result = ms->max_footprint;
4873 }
4874 USAGE_ERROR_ACTION(ms,ms);
4875 return result;
4876 }
4877
4878
4879 #if !NO_MALLINFO
4880 struct mallinfo mspace_mallinfo(mspace msp) {
4881 mstate ms = (mstate)msp;
4882 if (!ok_magic(ms)) {
4883 USAGE_ERROR_ACTION(ms,ms);
4884 }
4885 return internal_mallinfo(ms);
4886 }
4887 #endif /* NO_MALLINFO */
4888
4889 int mspace_mallopt(int param_number, int value) {
4890 return change_mparam(param_number, value);
4891 }
4892
4893 #endif /* MSPACES */
4894
4895 /* -------------------- Alternative MORECORE functions ------------------- */
4896
4897 /*
4898 Guidelines for creating a custom version of MORECORE:
4899
4900 * For best performance, MORECORE should allocate in multiples of pagesize.
4901 * MORECORE may allocate more memory than requested. (Or even less,
4902 but this will usually result in a malloc failure.)
4903 * MORECORE must not allocate memory when given argument zero, but
4904 instead return one past the end address of memory from previous
4905 nonzero call.
4906 * For best performance, consecutive calls to MORECORE with positive
4907 arguments should return increasing addresses, indicating that
4908 space has been contiguously extended.
4909 * Even though consecutive calls to MORECORE need not return contiguous
4910 addresses, it must be OK for malloc'ed chunks to span multiple
4911 regions in those cases where they do happen to be contiguous.
4912 * MORECORE need not handle negative arguments -- it may instead
4913 just return MFAIL when given negative arguments.
4914 Negative arguments are always multiples of pagesize. MORECORE
4915 must not misinterpret negative args as large positive unsigned
4916 args. You can suppress all such calls from even occurring by defining
4917 MORECORE_CANNOT_TRIM,
4918
4919 As an example alternative MORECORE, here is a custom allocator
4920 kindly contributed for pre-OSX macOS. It uses virtually but not
4921 necessarily physically contiguous non-paged memory (locked in,
4922 present and won't get swapped out). You can use it by uncommenting
4923 this section, adding some #includes, and setting up the appropriate
4924 defines above:
4925
4926 #define MORECORE osMoreCore
4927
4928 There is also a shutdown routine that should somehow be called for
4929 cleanup upon program exit.
4930
4931 #define MAX_POOL_ENTRIES 100
4932 #define MINIMUM_MORECORE_SIZE (64 * 1024U)
4933 static int next_os_pool;
4934 void *our_os_pools[MAX_POOL_ENTRIES];
4935
4936 void *osMoreCore(int size)
4937 {
4938 void *ptr = 0;
4939 static void *sbrk_top = 0;
4940
4941 if (size > 0)
4942 {
4943 if (size < MINIMUM_MORECORE_SIZE)
4944 size = MINIMUM_MORECORE_SIZE;
4945 if (CurrentExecutionLevel() == kTaskLevel)
4946 ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
4947 if (ptr == 0)
4948 {
4949 return (void *) MFAIL;
4950 }
4951 // save ptrs so they can be freed during cleanup
4952 our_os_pools[next_os_pool] = ptr;
4953 next_os_pool++;
4954 ptr = (void *) ((((size_t) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
4955 sbrk_top = (char *) ptr + size;
4956 return ptr;
4957 }
4958 else if (size < 0)
4959 {
4960 // we don't currently support shrink behavior
4961 return (void *) MFAIL;
4962 }
4963 else
4964 {
4965 return sbrk_top;
4966 }
4967 }
4968
4969 // cleanup any allocated memory pools
4970 // called as last thing before shutting down driver
4971
4972 void osCleanupMem(void)
4973 {
4974 void **ptr;
4975
4976 for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
4977 if (*ptr)
4978 {
4979 PoolDeallocate(*ptr);
4980 *ptr = 0;
4981 }
4982 }
4983
4984 */
4985
4986
4987 /* -----------------------------------------------------------------------
4988 History:
4989 V2.8.3 Thu Sep 22 11:16:32 2005 Doug Lea (dl at gee)
4990 * Add max_footprint functions
4991 * Ensure all appropriate literals are size_t
4992 * Fix conditional compilation problem for some #define settings
4993 * Avoid concatenating segments with the one provided
4994 in create_mspace_with_base
4995 * Rename some variables to avoid compiler shadowing warnings
4996 * Use explicit lock initialization.
4997 * Better handling of sbrk interference.
4998 * Simplify and fix segment insertion, trimming and mspace_destroy
4999 * Reinstate REALLOC_ZERO_BYTES_FREES option from 2.7.x
5000 * Thanks especially to Dennis Flanagan for help on these.
5001
5002 V2.8.2 Sun Jun 12 16:01:10 2005 Doug Lea (dl at gee)
5003 * Fix memalign brace error.
5004
5005 V2.8.1 Wed Jun 8 16:11:46 2005 Doug Lea (dl at gee)
5006 * Fix improper #endif nesting in C++
5007 * Add explicit casts needed for C++
5008
5009 V2.8.0 Mon May 30 14:09:02 2005 Doug Lea (dl at gee)
5010 * Use trees for large bins
5011 * Support mspaces
5012 * Use segments to unify sbrk-based and mmap-based system allocation,
5013 removing need for emulation on most platforms without sbrk.
5014 * Default safety checks
5015 * Optional footer checks. Thanks to William Robertson for the idea.
5016 * Internal code refactoring
5017 * Incorporate suggestions and platform-specific changes.
5018 Thanks to Dennis Flanagan, Colin Plumb, Niall Douglas,
5019 Aaron Bachmann, Emery Berger, and others.
5020 * Speed up non-fastbin processing enough to remove fastbins.
5021 * Remove useless cfree() to avoid conflicts with other apps.
5022 * Remove internal memcpy, memset. Compilers handle builtins better.
5023 * Remove some options that no one ever used and rename others.
5024
5025 V2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
5026 * Fix malloc_state bitmap array misdeclaration
5027
5028 V2.7.1 Thu Jul 25 10:58:03 2002 Doug Lea (dl at gee)
5029 * Allow tuning of FIRST_SORTED_BIN_SIZE
5030 * Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte.
5031 * Better detection and support for non-contiguousness of MORECORE.
5032 Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger
5033 * Bypass most of malloc if no frees. Thanks To Emery Berger.
5034 * Fix freeing of old top non-contiguous chunk im sysmalloc.
5035 * Raised default trim and map thresholds to 256K.
5036 * Fix mmap-related #defines. Thanks to Lubos Lunak.
5037 * Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield.
5038 * Branch-free bin calculation
5039 * Default trim and mmap thresholds now 256K.
5040
5041 V2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee)
5042 * Introduce independent_comalloc and independent_calloc.
5043 Thanks to Michael Pachos for motivation and help.
5044 * Make optional .h file available
5045 * Allow > 2GB requests on 32bit systems.
5046 * new WIN32 sbrk, mmap, munmap, lock code from <Walter@GeNeSys-e.de>.
5047 Thanks also to Andreas Mueller <a.mueller at paradatec.de>,
5048 and Anonymous.
5049 * Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for
5050 helping test this.)
5051 * memalign: check alignment arg
5052 * realloc: don't try to shift chunks backwards, since this
5053 leads to more fragmentation in some programs and doesn't
5054 seem to help in any others.
5055 * Collect all cases in malloc requiring system memory into sysmalloc
5056 * Use mmap as backup to sbrk
5057 * Place all internal state in malloc_state
5058 * Introduce fastbins (although similar to 2.5.1)
5059 * Many minor tunings and cosmetic improvements
5060 * Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK
5061 * Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
5062 Thanks to Tony E. Bennett <tbennett@nvidia.com> and others.
5063 * Include errno.h to support default failure action.
5064
5065 V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
5066 * return null for negative arguments
5067 * Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
5068 * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
5069 (e.g. WIN32 platforms)
5070 * Cleanup header file inclusion for WIN32 platforms
5071 * Cleanup code to avoid Microsoft Visual C++ compiler complaints
5072 * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
5073 memory allocation routines
5074 * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
5075 * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
5076 usage of 'assert' in non-WIN32 code
5077 * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
5078 avoid infinite loop
5079 * Always call 'fREe()' rather than 'free()'
5080
5081 V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
5082 * Fixed ordering problem with boundary-stamping
5083
5084 V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee)
5085 * Added pvalloc, as recommended by H.J. Liu
5086 * Added 64bit pointer support mainly from Wolfram Gloger
5087 * Added anonymously donated WIN32 sbrk emulation
5088 * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
5089 * malloc_extend_top: fix mask error that caused wastage after
5090 foreign sbrks
5091 * Add linux mremap support code from HJ Liu
5092
5093 V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee)
5094 * Integrated most documentation with the code.
5095 * Add support for mmap, with help from
5096 Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
5097 * Use last_remainder in more cases.
5098 * Pack bins using idea from colin@nyx10.cs.du.edu
5099 * Use ordered bins instead of best-fit threshold
5100 * Eliminate block-local decls to simplify tracing and debugging.
5101 * Support another case of realloc via move into top
5102 * Fix error occurring when initial sbrk_base not word-aligned.
5103 * Rely on page size for units instead of SBRK_UNIT to
5104 avoid surprises about sbrk alignment conventions.
5105 * Add mallinfo, mallopt. Thanks to Raymond Nijssen
5106 (raymond@es.ele.tue.nl) for the suggestion.
5107 * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
5108 * More precautions for cases where other routines call sbrk,
5109 courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
5110 * Added macros etc., allowing use in linux libc from
5111 H.J. Lu (hjl@gnu.ai.mit.edu)
5112 * Inverted this history list
5113
5114 V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee)
5115 * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
5116 * Removed all preallocation code since under current scheme
5117 the work required to undo bad preallocations exceeds
5118 the work saved in good cases for most test programs.
5119 * No longer use return list or unconsolidated bins since
5120 no scheme using them consistently outperforms those that don't
5121 given above changes.
5122 * Use best fit for very large chunks to prevent some worst-cases.
5123 * Added some support for debugging
5124
5125 V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee)
5126 * Removed footers when chunks are in use. Thanks to
5127 Paul Wilson (wilson@cs.texas.edu) for the suggestion.
5128
5129 V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee)
5130 * Added malloc_trim, with help from Wolfram Gloger
5131 (wmglo@Dent.MED.Uni-Muenchen.DE).
5132
5133 V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g)
5134
5135 V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g)
5136 * realloc: try to expand in both directions
5137 * malloc: swap order of clean-bin strategy;
5138 * realloc: only conditionally expand backwards
5139 * Try not to scavenge used bins
5140 * Use bin counts as a guide to preallocation
5141 * Occasionally bin return list chunks in first scan
5142 * Add a few optimizations from colin@nyx10.cs.du.edu
5143
5144 V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g)
5145 * faster bin computation & slightly different binning
5146 * merged all consolidations to one part of malloc proper
5147 (eliminating old malloc_find_space & malloc_clean_bin)
5148 * Scan 2 returns chunks (not just 1)
5149 * Propagate failure in realloc if malloc returns 0
5150 * Add stuff to allow compilation on non-ANSI compilers
5151 from kpv@research.att.com
5152
5153 V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu)
5154 * removed potential for odd address access in prev_chunk
5155 * removed dependency on getpagesize.h
5156 * misc cosmetics and a bit more internal documentation
5157 * anticosmetics: mangled names in macros to evade debugger strangeness
5158 * tested on sparc, hp-700, dec-mips, rs6000
5159 with gcc & native cc (hp, dec only) allowing
5160 Detlefs & Zorn comparison study (in SIGPLAN Notices.)
5161
5162 Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu)
5163 * Based loosely on libg++-1.2X malloc. (It retains some of the overall
5164 structure of old version, but most details differ.)
5165
5166 */