1 | /* Formatted output to strings. |
2 | Copyright (C) 2004, 2006-2019 Free Software Foundation, Inc. |
3 | Written by Simon Josefsson and Yoann Vandoorselaere <yoann@prelude-ids.org>. |
4 | |
5 | This program is free software; you can redistribute it and/or modify |
6 | it under the terms of the GNU General Public License as published by |
7 | the Free Software Foundation; either version 3, or (at your option) |
8 | any later version. |
9 | |
10 | This program is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 | GNU General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU General Public License along |
16 | with this program; if not, see <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #if 1 |
19 | # include <config.h> |
20 | #endif |
21 | |
22 | /* Specification. */ |
23 | #include <stdio.h> |
24 | |
25 | #include <errno.h> |
26 | #include <limits.h> |
27 | #include <stdarg.h> |
28 | #include <stdlib.h> |
29 | #include <string.h> |
30 | |
31 | #include "vasnprintf.h" |
32 | |
33 | /* Print formatted output to string STR. Similar to vsprintf, but |
34 | additional length SIZE limit how much is written into STR. Returns |
35 | string length of formatted string (which may be larger than SIZE). |
36 | STR may be NULL, in which case nothing will be written. On error, |
37 | return a negative value. */ |
38 | int |
39 | vsnprintf (char *str, size_t size, const char *format, va_list args) |
40 | { |
41 | char *output; |
42 | size_t len; |
43 | size_t lenbuf = size; |
44 | |
45 | output = vasnprintf (str, &lenbuf, format, args); |
46 | len = lenbuf; |
47 | |
48 | if (!output) |
49 | return -1; |
50 | |
51 | if (output != str) |
52 | { |
53 | if (size) |
54 | { |
55 | size_t pruned_len = (len < size ? len : size - 1); |
56 | memcpy (str, output, pruned_len); |
57 | str[pruned_len] = '\0'; |
58 | } |
59 | |
60 | free (output); |
61 | } |
62 | |
63 | if (len > INT_MAX) |
64 | { |
65 | errno = EOVERFLOW; |
66 | return -1; |
67 | } |
68 | |
69 | return len; |
70 | } |
71 | |