1/* Formatted output to strings.
2   Copyright (C) 2004, 2006-2012 Free Software Foundation, Inc.
3
4   This program is free software: you can redistribute it and/or modify
5   it under the terms of the GNU General Public License as published by
6   the Free Software Foundation; either version 3 of the License, or
7   (at your option) any later version.
8
9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
16
17#if 1
18# include <config.h>
19#endif
20
21/* Specification.  */
22#include <stdio.h>
23
24#include <errno.h>
25#include <limits.h>
26#include <stdarg.h>
27#include <stdint.h>
28#include <stdlib.h>
29
30#include "vasnprintf.h"
31
32#ifndef SIZE_MAX
33# define SIZE_MAX ((size_t) -1)
34#endif
35
36/* Print formatted output to string STR.
37   Return string length of formatted string.  On error, return a negative
38   value.  */
39int
40vsprintf (char *str, const char *format, va_list args)
41{
42  char *output;
43  size_t len;
44  size_t lenbuf;
45
46  /* vasnprintf fails with EOVERFLOW when the buffer size argument is larger
47     than INT_MAX (if that fits into a 'size_t' at all).
48     Also note that glibc's iconv fails with E2BIG when we pass a length that
49     is so large that str + lenbuf wraps around, i.e.
50     (uintptr_t) (str + lenbuf) < (uintptr_t) str.
51     Therefore set lenbuf = min (SIZE_MAX, INT_MAX, - (uintptr_t) str - 1).  */
52  lenbuf = (SIZE_MAX < INT_MAX ? SIZE_MAX : INT_MAX);
53  if (lenbuf > ~ (uintptr_t) str)
54    lenbuf = ~ (uintptr_t) str;
55
56  output = vasnprintf (str, &lenbuf, format, args);
57  len = lenbuf;
58
59  if (!output)
60    return -1;
61
62  if (output != str)
63    {
64      /* len is near SIZE_MAX.  */
65      free (output);
66      errno = EOVERFLOW;
67      return -1;
68    }
69
70  if (len > INT_MAX)
71    {
72      errno = EOVERFLOW;
73      return -1;
74    }
75
76  return len;
77}
78