Re: [Bug-gnulib] vasprintf proposed fix for int overflow check

[Bruno Haible]

> 2003-10-29  Paul Eggert  <address@hidden>
>
>       * vasprintf.c: Include <errno.h>, <limits.h>, <stdlib.h>.
>       (vasprintf) [defined EOVERFLOW]: If the resulting length
>       exceeds INT_MAX, report an EOVERFLOW error.

Well spotted (although highly theoretical if you don't have a machine
with lots of RAM ;-)).

Since asprintf() and vasprintf() are not specified to set errno in case
of failure - neither in our vasprintf.h nor in glibc's documentation -
you don't need to care about EOVERFLOW. I've thus committed this patch.


2003-10-30  Paul Eggert  <address@hidden>
            Bruno Haible  <address@hidden>

        * vasprintf.c: Include <limits.h>, <stdlib.h>.
        (vasprintf): Fail if the resulting length doesn't fit in an 'int'.

diff -c -3 -r1.2 vasprintf.c
*** vasprintf.c 14 Jul 2003 22:44:04 -0000      1.2
--- vasprintf.c 30 Oct 2003 14:05:15 -0000
***************
*** 1,5 ****
  /* Formatted output to strings.
!    Copyright (C) 1999, 2002 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
--- 1,5 ----
  /* Formatted output to strings.
!    Copyright (C) 1999, 2002-2003 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
***************
*** 22,27 ****
--- 22,30 ----
  /* Specification.  */
  #include "vasprintf.h"
  
+ #include <limits.h>
+ #include <stdlib.h>
+ 
  #include "vasnprintf.h"
  
  int
***************
*** 31,36 ****
--- 34,47 ----
    char *result = vasnprintf (NULL, &length, format, args);
    if (result == NULL)
      return -1;
+   if (length > INT_MAX)
+     {
+       /* We could produce such a big string, but can't return its length
+        as an 'int'.  */
+       free (result);
+       return -1;
+     }
+ 
    *resultp = result;
    /* Return the number of resulting bytes, excluding the trailing NUL.  */
    return length;