Re: [Bug-gnulib] localcharset.c: proposed patch to avoid leak upon realloc failure

[Bruno Haible]

Jim Meyering wrote:
> When realloc fails in localcharset's get_charset_aliases,
> it can clobber the sole pointer to a block of malloc'd memory,
> thus leaking that block.
>
> Here's a proposed patch:
>
> 2004-04-20  Jim Meyering  <address@hidden>
>
>       * localcharset.c (get_charset_aliases) [!VMS && !WIN32]:
>       Don't leak upon realloc failure.

Thanks. I'm using this patch, which looks a little bit more symmetrical.

diff -c -3 -r1.16 localcharset.c
*** localcharset.c      24 Dec 2003 13:07:08 -0000      1.16
--- localcharset.c      20 Apr 2004 10:56:26 -0000
***************
*** 1,6 ****
  /* Determine a canonical name for the current locale's character encoding.
  
!    Copyright (C) 2000-2003 Free Software Foundation, Inc.
  
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
--- 1,6 ----
  /* Determine a canonical name for the current locale's character encoding.
  
!    Copyright (C) 2000-2004 Free Software Foundation, Inc.
  
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
***************
*** 140,154 ****
        else
        {
          /* Parse the file's contents.  */
-         int c;
-         char buf1[50+1];
-         char buf2[50+1];
          char *res_ptr = NULL;
          size_t res_size = 0;
-         size_t l1, l2;
  
          for (;;)
            {
              c = getc (fp);
              if (c == EOF)
                break;
--- 140,156 ----
        else
        {
          /* Parse the file's contents.  */
          char *res_ptr = NULL;
          size_t res_size = 0;
  
          for (;;)
            {
+             int c;
+             char buf1[50+1];
+             char buf2[50+1];
+             size_t l1, l2;
+             char *old_res_ptr;
+ 
              c = getc (fp);
              if (c == EOF)
                break;
***************
*** 169,174 ****
--- 171,177 ----
                break;
              l1 = strlen (buf1);
              l2 = strlen (buf2);
+             old_res_ptr = res_ptr;
              if (res_size == 0)
                {
                  res_size = l1 + 1 + l2 + 1;
***************
*** 183,188 ****
--- 186,193 ----
                {
                  /* Out of memory. */
                  res_size = 0;
+                 if (old_res_ptr != NULL)
+                   free (old_res_ptr);
                  break;
                }
              strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);