lib/safe-alloc.h

   1 /* safe-alloc.h: safer memory allocation
   2
   3    Copyright (C) 2009-2024 Free Software Foundation, Inc.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Daniel Berrange and Paul Eggert.  */
  19
  20 #ifndef SAFE_ALLOC_H_
  21 #define SAFE_ALLOC_H_
  22
  23 /* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE,
  24    _GL_ATTRIBUTE_NODISCARD.  */
  25 #if !_GL_CONFIG_H_INCLUDED
  26  #error "Please include config.h first."
  27 #endif
  28
  29 #include <stdlib.h>
  30 #if defined __CHERI_PURE_CAPABILITY__
  31 # include <cheri.h>
  32 #endif
  33
  34 _GL_INLINE_HEADER_BEGIN
  35 #ifndef SAFE_ALLOC_INLINE
  36 # define SAFE_ALLOC_INLINE _GL_INLINE
  37 #endif
  38
  39 /* Don't call these directly - use the macros below.  */
  40 SAFE_ALLOC_INLINE void *
  41 safe_alloc_realloc_n (void *ptr, size_t count, size_t size)
  42 {
  43   size_t countx = count;
  44   size_t sizex = size;
  45   if (count == 0 || size == 0)
  46     countx = sizex = 1;
  47   ptr = reallocarray (ptr, countx, sizex);
  48 #if defined __CHERI_PURE_CAPABILITY__
  49   if (ptr != NULL && (count == 0 || size == 0))
  50     ptr = cheri_bounds_set (ptr, 0);
  51 #endif
  52   return ptr;
  53 }
  54 _GL_ATTRIBUTE_NODISCARD SAFE_ALLOC_INLINE int
  55 safe_alloc_check (void *ptr)
  56 {
  57   /* Return 0 if the allocation was successful, -1 otherwise.  */
  58   return -!ptr;
  59 }
  60
  61 /**
  62  * ALLOC:
  63  * @ptr: pointer to allocated memory
  64  *
  65  * Allocate sizeof *ptr bytes of memory and store
  66  * the address of allocated memory in 'ptr'.  Fill the
  67  * newly allocated memory with zeros.
  68  *
  69  * Return -1 on failure to allocate, zero on success.
  70  */
  71 #define ALLOC(ptr) ALLOC_N (ptr, 1)
  72
  73 /**
  74  * ALLOC_N:
  75  * @ptr: pointer to allocated memory
  76  * @count: number of elements to allocate
  77  *
  78  * Allocate an array of 'count' elements, each sizeof *ptr
  79  * bytes long and store the address of allocated memory in
  80  * 'ptr'.  Fill the newly allocated memory with zeros.
  81  *
  82  * Return -1 on failure, 0 on success.
  83  */
  84 #define ALLOC_N(ptr, count) \
  85   safe_alloc_check ((ptr) = calloc (count, sizeof *(ptr)))
  86
  87 /**
  88  * ALLOC_N_UNINITIALIZED:
  89  * @ptr: pointer to allocated memory
  90  * @count: number of elements to allocate
  91  *
  92  * Allocate an array of 'count' elements, each sizeof *ptr
  93  * bytes long and store the address of allocated memory in
  94  * 'ptr'.  Do not initialize the new memory at all.
  95  *
  96  * Return -1 on failure to allocate, zero on success.
  97  */
  98 #define ALLOC_N_UNINITIALIZED(ptr, count) \
  99   safe_alloc_check ((ptr) = safe_alloc_realloc_n (NULL, count, sizeof *(ptr)))
 100
 101 /**
 102  * REALLOC_N:
 103  * @ptr: pointer to allocated memory
 104  * @count: number of elements to allocate
 105  *
 106  * Re-allocate an array of 'count' elements, each sizeof *ptr
 107  * bytes long and store the address of allocated memory in
 108  * 'ptr'.  Fill the newly allocated memory with zeros.
 109  *
 110  * Return -1 on failure to reallocate, zero on success.
 111  */
 112 #define REALLOC_N(ptr, count) \
 113   safe_alloc_check ((ptr) = safe_alloc_realloc_n (ptr, count, sizeof *(ptr)))
 114
 115 /**
 116  * FREE:
 117  * @ptr: pointer holding address to be freed
 118  *
 119  * Free the memory stored in 'ptr' and update to point
 120  * to NULL.
 121  */
 122 #define FREE(ptr) ((void) (free (ptr), (ptr) = NULL))
 123
 124 _GL_INLINE_HEADER_END
 125
 126 #endif /* SAFE_ALLOC_H_ */