]>
Commit | Line | Data |
---|---|---|
97d9957b | 1 | /* Copyright (C) 1994,96,97,98,99,2000 Free Software Foundation, Inc. |
d629bcec UD |
2 | This file is part of the GNU C Library. |
3 | ||
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. | |
d629bcec UD |
8 | |
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. |
d629bcec | 13 | |
41bdb6e2 AJ |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, write to the Free | |
16 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
17 | 02111-1307 USA. */ | |
d629bcec UD |
18 | |
19 | #include <sys/types.h> | |
20 | #include <unistd.h> | |
21 | #include <fcntl.h> | |
22 | #include <errno.h> | |
23 | #include <string.h> | |
24 | ||
25 | /* lockf is a simplified interface to fcntl's locking facilities. */ | |
26 | ||
27 | int | |
28 | lockf64 (int fd, int cmd, off64_t len64) | |
29 | { | |
30 | struct flock fl; | |
31 | off_t len = (off_t) len64; | |
32 | ||
33 | if (len64 != (off64_t) len) | |
97d9957b AJ |
34 | { |
35 | /* We can't represent the length. */ | |
36 | __set_errno (EOVERFLOW); | |
37 | return -1; | |
38 | } | |
d629bcec UD |
39 | |
40 | memset ((char *) &fl, '\0', sizeof (fl)); | |
41 | ||
42 | /* lockf is always relative to the current file position. */ | |
43 | fl.l_whence = SEEK_CUR; | |
44 | fl.l_start = 0; | |
45 | fl.l_len = len; | |
46 | ||
47 | switch (cmd) | |
48 | { | |
49 | case F_TEST: | |
50 | /* Test the lock: return 0 if FD is unlocked or locked by this process; | |
51 | return -1, set errno to EACCES, if another process holds the lock. */ | |
35b99c57 | 52 | fl.l_type = F_RDLCK; |
d629bcec UD |
53 | if (__fcntl (fd, F_GETLK, &fl) < 0) |
54 | return -1; | |
55 | if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ()) | |
56 | return 0; | |
57 | __set_errno (EACCES); | |
58 | return -1; | |
59 | ||
60 | case F_ULOCK: | |
61 | fl.l_type = F_UNLCK; | |
62 | cmd = F_SETLK; | |
63 | break; | |
64 | case F_LOCK: | |
65 | fl.l_type = F_WRLCK; | |
66 | cmd = F_SETLKW; | |
67 | break; | |
68 | case F_TLOCK: | |
69 | fl.l_type = F_WRLCK; | |
70 | cmd = F_SETLK; | |
71 | break; | |
72 | ||
73 | default: | |
74 | __set_errno (EINVAL); | |
75 | return -1; | |
76 | } | |
77 | ||
78 | return __fcntl (fd, cmd, &fl); | |
79 | } |