source3/lib/util_malloc.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba utility functions
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 2001-2007
   6    Copyright (C) Simo Sorce 2001
   7    Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2003
   8    Copyright (C) James Peach 2006
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25
  26 #if defined(PARANOID_MALLOC_CHECKER)
  27
  28 /****************************************************************************
  29  Internal malloc wrapper. Externally visible.
  30 ****************************************************************************/
  31
  32 void *malloc_(size_t size)
  33 {
  34         if (size == 0) {
  35                 return NULL;
  36         }
  37 #undef malloc
  38         return malloc(size);
  39 #define malloc(s) __ERROR_DONT_USE_MALLOC_DIRECTLY
  40 }
  41
  42 /****************************************************************************
  43  Internal realloc wrapper. Not externally visible.
  44 ****************************************************************************/
  45
  46 static void *realloc_(void *ptr, size_t size)
  47 {
  48 #undef realloc
  49         return realloc(ptr, size);
  50 #define realloc(p,s) __ERROR_DONT_USE_RELLOC_DIRECTLY
  51 }
  52
  53 #endif /* PARANOID_MALLOC_CHECKER */
  54
  55 /****************************************************************************
  56  Expand a pointer to be a particular size.
  57  Note that this version of Realloc has an extra parameter that decides
  58  whether to free the passed in storage on allocation failure or if the
  59  new size is zero.
  60
  61  This is designed for use in the typical idiom of :
  62
  63  p = SMB_REALLOC(p, size)
  64  if (!p) {
  65     return error;
  66  }
  67
  68  and not to have to keep track of the old 'p' contents to free later, nor
  69  to worry if the size parameter was zero. In the case where NULL is returned
  70  we guarentee that p has been freed.
  71
  72  If free later semantics are desired, then pass 'free_old_on_error' as False which
  73  guarentees that the old contents are not freed on error, even if size == 0. To use
  74  this idiom use :
  75
  76  tmp = SMB_REALLOC_KEEP_OLD_ON_ERROR(p, size);
  77  if (!tmp) {
  78     SAFE_FREE(p);
  79     return error;
  80  } else {
  81     p = tmp;
  82  }
  83
  84  Changes were instigated by Coverity error checking. JRA.
  85 ****************************************************************************/
  86
  87 void *Realloc(void *p, size_t size, bool free_old_on_error)
  88 {
  89         void *ret=NULL;
  90
  91         if (size == 0) {
  92                 if (free_old_on_error) {
  93                         SAFE_FREE(p);
  94                 }
  95                 DEBUG(2,("Realloc asked for 0 bytes\n"));
  96                 return NULL;
  97         }
  98
  99 #if defined(PARANOID_MALLOC_CHECKER)
 100         if (!p) {
 101                 ret = (void *)malloc_(size);
 102         } else {
 103                 ret = (void *)realloc_(p,size);
 104         }
 105 #else
 106         if (!p) {
 107                 ret = (void *)malloc(size);
 108         } else {
 109                 ret = (void *)realloc(p,size);
 110         }
 111 #endif
 112
 113         if (!ret) {
 114                 if (free_old_on_error && p) {
 115                         SAFE_FREE(p);
 116                 }
 117                 DEBUG(0,("Memory allocation error: failed to expand to %d bytes\n",(int)size));
 118         }
 119
 120         return(ret);
 121 }
 122