1/* Formatted output to strings.
2 Copyright (C) 2004, 2006-2019 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 <https://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