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c1760eaf3b
To help detect common kinds of memory (and other resource) management bugs, GCC 11 adds support for the detection of mismatched calls to allocation and deallocation functions. At each call site to a known deallocation function GCC checks the set of allocation functions the former can be paired with and, if the two don't match, issues a -Wmismatched-dealloc warning (something similar happens in C++ for mismatched calls to new and delete). GCC also uses the same mechanism to detect attempts to deallocate objects not allocated by any allocation function (or pointers past the first byte into allocated objects) by -Wfree-nonheap-object. This support is enabled for built-in functions like malloc and free. To extend it beyond those, GCC extends attribute malloc to designate a deallocation function to which pointers returned from the allocation function may be passed to deallocate the allocated objects. Another, optional argument designates the positional argument to which the pointer must be passed. This change is the first step in enabling this extended support for Glibc.
188 lines
7.0 KiB
C
188 lines
7.0 KiB
C
/* Prototypes and definition for malloc implementation.
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Copyright (C) 1996-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _MALLOC_H
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#define _MALLOC_H 1
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#include <features.h>
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#include <stddef.h>
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#include <stdio.h>
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#ifdef _LIBC
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# define __MALLOC_HOOK_VOLATILE
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# define __MALLOC_DEPRECATED
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#else
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# define __MALLOC_HOOK_VOLATILE volatile
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# define __MALLOC_DEPRECATED __attribute_deprecated__
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#endif
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__BEGIN_DECLS
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/* Allocate SIZE bytes of memory. */
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extern void *malloc (size_t __size) __THROW __attribute_malloc__
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__attribute_alloc_size__ ((1)) __wur;
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/* Allocate NMEMB elements of SIZE bytes each, all initialized to 0. */
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extern void *calloc (size_t __nmemb, size_t __size)
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__THROW __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __wur;
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/* Re-allocate the previously allocated block in __ptr, making the new
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block SIZE bytes long. */
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/* __attribute_malloc__ is not used, because if realloc returns
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the same pointer that was passed to it, aliasing needs to be allowed
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between objects pointed by the old and new pointers. */
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extern void *realloc (void *__ptr, size_t __size)
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__THROW __attribute_warn_unused_result__ __attribute_alloc_size__ ((2));
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/* Re-allocate the previously allocated block in PTR, making the new
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block large enough for NMEMB elements of SIZE bytes each. */
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/* __attribute_malloc__ is not used, because if reallocarray returns
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the same pointer that was passed to it, aliasing needs to be allowed
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between objects pointed by the old and new pointers. */
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extern void *reallocarray (void *__ptr, size_t __nmemb, size_t __size)
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__THROW __attribute_warn_unused_result__ __attribute_alloc_size__ ((2, 3))
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__attr_dealloc_free;
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/* Free a block allocated by `malloc', `realloc' or `calloc'. */
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extern void free (void *__ptr) __THROW;
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/* Allocate SIZE bytes allocated to ALIGNMENT bytes. */
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extern void *memalign (size_t __alignment, size_t __size)
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__THROW __attribute_malloc__ __attribute_alloc_size__ ((2)) __wur
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__attr_dealloc_free;
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/* Allocate SIZE bytes on a page boundary. */
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extern void *valloc (size_t __size) __THROW __attribute_malloc__
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__attribute_alloc_size__ ((1)) __wur __attr_dealloc_free;
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/* Equivalent to valloc(minimum-page-that-holds(n)), that is, round up
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__size to nearest pagesize. */
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extern void *pvalloc (size_t __size) __THROW __attribute_malloc__
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__wur __attr_dealloc_free;
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/* Underlying allocation function; successive calls should return
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contiguous pieces of memory. */
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extern void *(*__morecore) (ptrdiff_t __size) __MALLOC_DEPRECATED;
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/* Default value of `__morecore'. */
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extern void *__default_morecore (ptrdiff_t __size)
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__THROW __attribute_malloc__ __MALLOC_DEPRECATED;
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/* SVID2/XPG mallinfo structure */
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struct mallinfo
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{
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int arena; /* non-mmapped space allocated from system */
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int ordblks; /* number of free chunks */
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int smblks; /* number of fastbin blocks */
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int hblks; /* number of mmapped regions */
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int hblkhd; /* space in mmapped regions */
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int usmblks; /* always 0, preserved for backwards compatibility */
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int fsmblks; /* space available in freed fastbin blocks */
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int uordblks; /* total allocated space */
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int fordblks; /* total free space */
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int keepcost; /* top-most, releasable (via malloc_trim) space */
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};
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/* SVID2/XPG mallinfo2 structure which can handle allocations
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bigger than 4GB. */
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struct mallinfo2
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{
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size_t arena; /* non-mmapped space allocated from system */
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size_t ordblks; /* number of free chunks */
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size_t smblks; /* number of fastbin blocks */
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size_t hblks; /* number of mmapped regions */
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size_t hblkhd; /* space in mmapped regions */
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size_t usmblks; /* always 0, preserved for backwards compatibility */
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size_t fsmblks; /* space available in freed fastbin blocks */
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size_t uordblks; /* total allocated space */
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size_t fordblks; /* total free space */
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size_t keepcost; /* top-most, releasable (via malloc_trim) space */
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};
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/* Returns a copy of the updated current mallinfo. */
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extern struct mallinfo mallinfo (void) __THROW __MALLOC_DEPRECATED;
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/* Returns a copy of the updated current mallinfo. */
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extern struct mallinfo2 mallinfo2 (void) __THROW;
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/* SVID2/XPG mallopt options */
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#ifndef M_MXFAST
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# define M_MXFAST 1 /* maximum request size for "fastbins" */
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#endif
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#ifndef M_NLBLKS
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# define M_NLBLKS 2 /* UNUSED in this malloc */
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#endif
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#ifndef M_GRAIN
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# define M_GRAIN 3 /* UNUSED in this malloc */
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#endif
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#ifndef M_KEEP
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# define M_KEEP 4 /* UNUSED in this malloc */
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#endif
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/* mallopt options that actually do something */
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#define M_TRIM_THRESHOLD -1
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#define M_TOP_PAD -2
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#define M_MMAP_THRESHOLD -3
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#define M_MMAP_MAX -4
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#define M_CHECK_ACTION -5
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#define M_PERTURB -6
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#define M_ARENA_TEST -7
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#define M_ARENA_MAX -8
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/* General SVID/XPG interface to tunable parameters. */
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extern int mallopt (int __param, int __val) __THROW;
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/* Release all but __pad bytes of freed top-most memory back to the
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system. Return 1 if successful, else 0. */
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extern int malloc_trim (size_t __pad) __THROW;
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/* Report the number of usable allocated bytes associated with allocated
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chunk __ptr. */
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extern size_t malloc_usable_size (void *__ptr) __THROW;
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/* Prints brief summary statistics on stderr. */
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extern void malloc_stats (void) __THROW;
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/* Output information about state of allocator to stream FP. */
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extern int malloc_info (int __options, FILE *__fp) __THROW;
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/* Hooks for debugging and user-defined versions. */
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extern void (*__MALLOC_HOOK_VOLATILE __free_hook) (void *__ptr,
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const void *)
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__MALLOC_DEPRECATED;
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extern void *(*__MALLOC_HOOK_VOLATILE __malloc_hook)(size_t __size,
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const void *)
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__MALLOC_DEPRECATED;
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extern void *(*__MALLOC_HOOK_VOLATILE __realloc_hook)(void *__ptr,
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size_t __size,
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const void *)
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__MALLOC_DEPRECATED;
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extern void *(*__MALLOC_HOOK_VOLATILE __memalign_hook)(size_t __alignment,
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size_t __size,
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const void *)
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__MALLOC_DEPRECATED;
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extern void (*__MALLOC_HOOK_VOLATILE __after_morecore_hook) (void)
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__MALLOC_DEPRECATED;
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__END_DECLS
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#endif /* malloc.h */
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