lib/compat/vasprintf.c

   1 /*
   2  * libcompat - system compatibility library
   3  *
   4  * Copyright © 2010 Guillem Jover <guillem@debian.org>
   5  *
   6  * This is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21
  22 #include <errno.h>
  23 #include <limits.h>
  24 #include <stdarg.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27
  28 #include "compat.h"
  29
  30 int
  31 vasprintf(char **strp, char const *fmt, va_list args)
  32 {
  33         va_list args_copy;
  34         int needed, n;
  35         char *str;
  36
  37         va_copy(args_copy, args);
  38         needed = vsnprintf(NULL, 0, fmt, args_copy);
  39         va_end(args_copy);
  40
  41         if (needed < 0 || needed >= INT_MAX) {
  42                 if (needed >= INT_MAX)
  43                         errno = EOVERFLOW;
  44                 *strp = NULL;
  45                 return -1;
  46         }
  47
  48         str = malloc(needed + 1);
  49         if (str == NULL) {
  50                 *strp = NULL;
  51                 return -1;
  52         }
  53
  54         n = vsnprintf(str, needed + 1, fmt, args);
  55         if (n < 0) {
  56                 free(str);
  57                 str = NULL;
  58         }
  59
  60         *strp = str;
  61
  62         return n;
  63 }