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dff8da6b | 1 | /* Copyright (C) 1994-2024 Free Software Foundation, Inc. |
c84142e8 | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
c84142e8 | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
28f540f4 | 8 | |
c84142e8 UD |
9 | The GNU C Library 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 GNU | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
28f540f4 | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
28f540f4 | 17 | |
fda4d818 AF |
18 | #include <bits/types.h> |
19 | ||
e442e40d | 20 | #ifndef __OFF_T_MATCHES_OFF64_T |
03af9520 | 21 | |
28f540f4 | 22 | #include <unistd.h> |
e442e40d | 23 | #include <fcntl.h> |
28f540f4 RM |
24 | #include <errno.h> |
25 | ||
26 | /* lockf is a simplified interface to fcntl's locking facilities. */ | |
28f540f4 RM |
27 | int |
28 | lockf (int fd, int cmd, off_t len) | |
29 | { | |
bfce746a | 30 | /* lockf is always relative to the current file position. */ |
e442e40d AZ |
31 | struct flock fl = { |
32 | .l_type = F_WRLCK, | |
33 | .l_whence = SEEK_CUR, | |
34 | .l_len = len | |
35 | }; | |
bfce746a | 36 | |
e442e40d AZ |
37 | /* lockf() is a cancellation point but so is fcntl() if F_SETLKW is |
38 | used. Therefore we don't have to care about cancellation here, | |
39 | the fcntl() function will take care of it. */ | |
28f540f4 RM |
40 | switch (cmd) |
41 | { | |
42 | case F_TEST: | |
43 | /* Test the lock: return 0 if FD is unlocked or locked by this process; | |
44 | return -1, set errno to EACCES, if another process holds the lock. */ | |
9c3b1ceb | 45 | fl.l_type = F_RDLCK; |
50304ef0 | 46 | if (__fcntl (fd, F_GETLK, &fl) < 0) |
28f540f4 | 47 | return -1; |
50304ef0 | 48 | if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ()) |
28f540f4 | 49 | return 0; |
c4029823 | 50 | __set_errno (EACCES); |
28f540f4 | 51 | return -1; |
28f540f4 RM |
52 | case F_ULOCK: |
53 | fl.l_type = F_UNLCK; | |
e442e40d | 54 | return __fcntl (fd, F_SETLK, &fl); |
28f540f4 | 55 | case F_LOCK: |
e442e40d | 56 | return __fcntl (fd, F_SETLKW, &fl); |
28f540f4 | 57 | case F_TLOCK: |
e442e40d | 58 | return __fcntl (fd, F_SETLK, &fl); |
28f540f4 | 59 | } |
e442e40d AZ |
60 | __set_errno (EINVAL); |
61 | return -1; | |
28f540f4 | 62 | } |
03af9520 | 63 | #endif |