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 #ifdef __cplusplus
  40 extern "C" {
  41 #endif
  42
  43
  44 /* Don't call these directly - use the macros below.  */
  45 SAFE_ALLOC_INLINE void *
  46 safe_alloc_realloc_n (void *ptr, size_t count, size_t size)
  47 {
  48   size_t countx = count;
  49   size_t sizex = size;
  50   if (count == 0 || size == 0)
  51     countx = sizex = 1;
  52   ptr = reallocarray (ptr, countx, sizex);
  53 #if defined __CHERI_PURE_CAPABILITY__
  54   if (ptr != NULL && (count == 0 || size == 0))
  55     ptr = cheri_bounds_set (ptr, 0);
  56 #endif
  57   return ptr;
  58 }
  59 _GL_ATTRIBUTE_NODISCARD SAFE_ALLOC_INLINE int
  60 safe_alloc_check (void *ptr)
  61 {
  62   /* Return 0 if the allocation was successful, -1 otherwise.  */
  63   return -!ptr;
  64 }
  65
  66 /**
  67  * ALLOC:
  68  * @ptr: pointer to allocated memory
  69  *
  70  * Allocate sizeof *ptr bytes of memory and store
  71  * the address of allocated memory in 'ptr'.  Fill the
  72  * newly allocated memory with zeros.
  73  *
  74  * Return -1 on failure to allocate, zero on success.
  75  */
  76 #define ALLOC(ptr) ALLOC_N (ptr, 1)
  77
  78 /**
  79  * ALLOC_N:
  80  * @ptr: pointer to allocated memory
  81  * @count: number of elements to allocate
  82  *
  83  * Allocate an array of 'count' elements, each sizeof *ptr
  84  * bytes long and store the address of allocated memory in
  85  * 'ptr'.  Fill the newly allocated memory with zeros.
  86  *
  87  * Return -1 on failure, 0 on success.
  88  */
  89 #define ALLOC_N(ptr, count) \
  90   safe_alloc_check ((ptr) = calloc (count, sizeof *(ptr)))
  91
  92 /**
  93  * ALLOC_N_UNINITIALIZED:
  94  * @ptr: pointer to allocated memory
  95  * @count: number of elements to allocate
  96  *
  97  * Allocate an array of 'count' elements, each sizeof *ptr
  98  * bytes long and store the address of allocated memory in
  99  * 'ptr'.  Do not initialize the new memory at all.
 100  *
 101  * Return -1 on failure to allocate, zero on success.
 102  */
 103 #define ALLOC_N_UNINITIALIZED(ptr, count) \
 104   safe_alloc_check ((ptr) = safe_alloc_realloc_n (NULL, count, sizeof *(ptr)))
 105
 106 /**
 107  * REALLOC_N:
 108  * @ptr: pointer to allocated memory
 109  * @count: number of elements to allocate
 110  *
 111  * Re-allocate an array of 'count' elements, each sizeof *ptr
 112  * bytes long and store the address of allocated memory in
 113  * 'ptr'.  Fill the newly allocated memory with zeros.
 114  *
 115  * Return -1 on failure to reallocate, zero on success.
 116  */
 117 #define REALLOC_N(ptr, count) \
 118   safe_alloc_check ((ptr) = safe_alloc_realloc_n (ptr, count, sizeof *(ptr)))
 119
 120 /**
 121  * FREE:
 122  * @ptr: pointer holding address to be freed
 123  *
 124  * Free the memory stored in 'ptr' and update to point
 125  * to NULL.
 126  */
 127 #define FREE(ptr) ((void) (free (ptr), (ptr) = NULL))
 128
 129
 130 #ifdef __cplusplus
 131 }
 132 #endif
 133
 134 _GL_INLINE_HEADER_END
 135
 136 #endif /* SAFE_ALLOC_H_ */