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6ec2e0f5 SDJ |
1 | /* strerror.c --- POSIX compatible system error routine |
2 | ||
c0c3707f | 3 | Copyright (C) 2007-2019 Free Software Foundation, Inc. |
6ec2e0f5 SDJ |
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 of the License, or | |
8 | (at your option) 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 | |
c0c3707f | 16 | along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
6ec2e0f5 SDJ |
17 | |
18 | #include <config.h> | |
19 | ||
20 | /* Specification. */ | |
21 | #include <string.h> | |
22 | ||
23 | #include <errno.h> | |
24 | #include <stdio.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | ||
28 | #include "intprops.h" | |
29 | #include "strerror-override.h" | |
30 | #include "verify.h" | |
31 | ||
32 | /* Use the system functions, not the gnulib overrides in this file. */ | |
33 | #undef sprintf | |
34 | ||
35 | char * | |
36 | strerror (int n) | |
37 | #undef strerror | |
38 | { | |
39 | static char buf[STACKBUF_LEN]; | |
40 | size_t len; | |
41 | ||
42 | /* Cast away const, due to the historical signature of strerror; | |
43 | callers should not be modifying the string. */ | |
44 | const char *msg = strerror_override (n); | |
45 | if (msg) | |
46 | return (char *) msg; | |
47 | ||
48 | msg = strerror (n); | |
49 | ||
50 | /* Our strerror_r implementation might use the system's strerror | |
51 | buffer, so all other clients of strerror have to see the error | |
52 | copied into a buffer that we manage. This is not thread-safe, | |
53 | even if the system strerror is, but portable programs shouldn't | |
54 | be using strerror if they care about thread-safety. */ | |
55 | if (!msg || !*msg) | |
56 | { | |
57 | static char const fmt[] = "Unknown error %d"; | |
58 | verify (sizeof buf >= sizeof (fmt) + INT_STRLEN_BOUND (n)); | |
59 | sprintf (buf, fmt, n); | |
60 | errno = EINVAL; | |
61 | return buf; | |
62 | } | |
63 | ||
64 | /* Fix STACKBUF_LEN if this ever aborts. */ | |
65 | len = strlen (msg); | |
66 | if (sizeof buf <= len) | |
67 | abort (); | |
68 | ||
c0c3707f CB |
69 | memcpy (buf, msg, len + 1); |
70 | return buf; | |
6ec2e0f5 | 71 | } |