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. */ |
39 | int |
40 | vsprintf (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 | |