Mercurial > hg > octave-kai > gnulib-hg
annotate lib/chdir-safer.c @ 9309:bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
| author | Bruno Haible <bruno@clisp.org> |
|---|---|
| date | Sun, 07 Oct 2007 19:14:58 +0200 |
| parents | 8a1a9361108c |
| children | cfa44ca8e7ba |
| rev | line source |
|---|---|
| 6527 | 1 /* much like chdir(2), but safer |
| 2 | |
| 3 Copyright (C) 2005, 2006 Free Software Foundation, Inc. | |
| 4 | |
|
9309
bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
Bruno Haible <bruno@clisp.org>
parents:
7302
diff
changeset
|
5 This program is free software: you can redistribute it and/or modify |
| 6527 | 6 it under the terms of the GNU General Public License as published by |
|
9309
bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
Bruno Haible <bruno@clisp.org>
parents:
7302
diff
changeset
|
7 the Free Software Foundation; either version 3 of the License, or |
|
bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
Bruno Haible <bruno@clisp.org>
parents:
7302
diff
changeset
|
8 (at your option) any later version. |
| 6527 | 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 | |
|
9309
bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
Bruno Haible <bruno@clisp.org>
parents:
7302
diff
changeset
|
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 6527 | 17 |
| 18 /* written by Jim Meyering */ | |
| 19 | |
|
7302
8a1a9361108c
* _fpending.c: Include <config.h> unconditionally, since we no
Paul Eggert <eggert@cs.ucla.edu>
parents:
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diff
changeset
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20 #include <config.h> |
| 6527 | 21 |
| 22 #include "chdir-safer.h" | |
| 23 | |
| 24 #include <stdbool.h> | |
| 25 #include <fcntl.h> | |
| 26 #include <errno.h> | |
| 27 #include <unistd.h> | |
| 28 #include <sys/types.h> | |
| 29 #include <sys/stat.h> | |
| 6912 | 30 #include "same-inode.h" |
| 6527 | 31 |
| 32 /* Like chdir, but fail if DIR is a symbolic link to a directory (or | |
| 33 similar funny business), or if DIR is not readable. This avoids a | |
| 34 minor race condition between when a directory is created or statted | |
| 35 and when the process chdirs into it. */ | |
| 36 int | |
| 37 chdir_no_follow (char const *dir) | |
| 38 { | |
| 39 int result = 0; | |
| 40 int saved_errno; | |
| 41 int fd = open (dir, | |
| 42 O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NOFOLLOW | O_NONBLOCK); | |
| 43 if (fd < 0) | |
| 44 return -1; | |
| 45 | |
| 46 /* If open follows symlinks, lstat DIR and fstat FD to ensure that | |
| 47 they are the same file; if they are different files, set errno to | |
| 48 ELOOP (the same value that open uses for symlinks with | |
| 49 O_NOFOLLOW) so the caller can report a failure. */ | |
| 50 if (! O_NOFOLLOW) | |
| 51 { | |
| 52 struct stat sb1; | |
| 53 result = lstat (dir, &sb1); | |
| 54 if (result == 0) | |
| 55 { | |
| 56 struct stat sb2; | |
| 57 result = fstat (fd, &sb2); | |
| 58 if (result == 0 && ! SAME_INODE (sb1, sb2)) | |
| 59 { | |
| 60 errno = ELOOP; | |
| 61 result = -1; | |
| 62 } | |
| 63 } | |
| 64 } | |
| 65 | |
| 66 if (result == 0) | |
| 67 result = fchdir (fd); | |
| 68 | |
| 69 saved_errno = errno; | |
| 70 close (fd); | |
| 71 errno = saved_errno; | |
| 72 return result; | |
| 73 } |