1 | /* Invoke fopen, but avoid some glitches. |
2 | |
3 | Copyright (C) 2001, 2004-2006, 2009-2019 Free Software Foundation, Inc. |
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 |
16 | along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
17 | |
18 | /* Written by Paul Eggert. */ |
19 | |
20 | #include <config.h> |
21 | |
22 | #include "stdio-safer.h" |
23 | |
24 | #include <errno.h> |
25 | #include <unistd.h> |
26 | #include "unistd-safer.h" |
27 | |
28 | /* Like fopen, but do not return stdin, stdout, or stderr. */ |
29 | |
30 | FILE * |
31 | fopen_safer (char const *file, char const *mode) |
32 | { |
33 | FILE *fp = fopen (file, mode); |
34 | |
35 | if (fp) |
36 | { |
37 | int fd = fileno (fp); |
38 | |
39 | if (0 <= fd && fd <= STDERR_FILENO) |
40 | { |
41 | int f = dup_safer (fd); |
42 | |
43 | if (f < 0) |
44 | { |
45 | int e = errno; |
46 | fclose (fp); |
47 | errno = e; |
48 | return NULL; |
49 | } |
50 | |
51 | if (fclose (fp) != 0 |
52 | || ! (fp = fdopen (f, mode))) |
53 | { |
54 | int e = errno; |
55 | close (f); |
56 | errno = e; |
57 | return NULL; |
58 | } |
59 | } |
60 | } |
61 | |
62 | return fp; |
63 | } |
64 | |