lib/xmalloc.c

   1 /* xmalloc.c -- malloc with out of memory checking
   2
   3    Copyright (C) 1990-2000, 2002-2006, 2008-2019 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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 General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 #define XALLOC_INLINE _GL_EXTERN_INLINE
  21
  22 #include "xalloc.h"
  23
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 /* 1 if calloc is known to be compatible with GNU calloc.  This
  28    matters if we are not also using the calloc module, which defines
  29    HAVE_CALLOC_GNU and supports the GNU API even on non-GNU platforms.  */
  30 #if defined HAVE_CALLOC_GNU || (defined __GLIBC__ && !defined __UCLIBC__)
  31 enum { HAVE_GNU_CALLOC = 1 };
  32 #else
  33 enum { HAVE_GNU_CALLOC = 0 };
  34 #endif
  35
  36 /* Allocate N bytes of memory dynamically, with error checking.  */
  37
  38 void *
  39 xmalloc (size_t n)
  40 {
  41   void *p = malloc (n);
  42   if (!p && n != 0)
  43     xalloc_die ();
  44   return p;
  45 }
  46
  47 /* Change the size of an allocated block of memory P to N bytes,
  48    with error checking.  */
  49
  50 void *
  51 xrealloc (void *p, size_t n)
  52 {
  53   if (!n && p)
  54     {
  55       /* The GNU and C99 realloc behaviors disagree here.  Act like
  56          GNU, even if the underlying realloc is C99.  */
  57       free (p);
  58       return NULL;
  59     }
  60
  61   p = realloc (p, n);
  62   if (!p && n)
  63     xalloc_die ();
  64   return p;
  65 }
  66
  67 /* If P is null, allocate a block of at least *PN bytes; otherwise,
  68    reallocate P so that it contains more than *PN bytes.  *PN must be
  69    nonzero unless P is null.  Set *PN to the new block's size, and
  70    return the pointer to the new block.  *PN is never set to zero, and
  71    the returned pointer is never null.  */
  72
  73 void *
  74 x2realloc (void *p, size_t *pn)
  75 {
  76   return x2nrealloc (p, pn, 1);
  77 }
  78
  79 /* Allocate S bytes of zeroed memory dynamically, with error checking.
  80    There's no need for xnzalloc (N, S), since it would be equivalent
  81    to xcalloc (N, S).  */
  82
  83 void *
  84 xzalloc (size_t s)
  85 {
  86   return memset (xmalloc (s), 0, s);
  87 }
  88
  89 /* Allocate zeroed memory for N elements of S bytes, with error
  90    checking.  S must be nonzero.  */
  91
  92 void *
  93 xcalloc (size_t n, size_t s)
  94 {
  95   void *p;
  96   /* Test for overflow, since objects with size greater than
  97      PTRDIFF_MAX cause pointer subtraction to go awry.  Omit size-zero
  98      tests if HAVE_GNU_CALLOC, since GNU calloc never returns NULL if
  99      successful.  */
 100   if (xalloc_oversized (n, s)
 101       || (! (p = calloc (n, s)) && (HAVE_GNU_CALLOC || n != 0)))
 102     xalloc_die ();
 103   return p;
 104 }
 105
 106 /* Clone an object P of size S, with error checking.  There's no need
 107    for xnmemdup (P, N, S), since xmemdup (P, N * S) works without any
 108    need for an arithmetic overflow check.  */
 109
 110 void *
 111 xmemdup (void const *p, size_t s)
 112 {
 113   return memcpy (xmalloc (s), p, s);
 114 }
 115
 116 /* Clone STRING.  */
 117
 118 char *
 119 xstrdup (char const *string)
 120 {
 121   return xmemdup (string, strlen (string) + 1);
 122 }