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568035b7 | 1 | /* Copyright (C) 1994-2013 Free Software Foundation, Inc. |
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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 | |
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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. | |
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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 | 14 | You should have received a copy of the GNU Lesser General Public |
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15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
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17 | |
18 | #include <sys/types.h> | |
19 | #include <unistd.h> | |
20 | #include <fcntl.h> | |
21 | #include <errno.h> | |
22 | #include <string.h> | |
23 | ||
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24 | /* lockf.c defines lockf64 as an lias if __OFF_T_MATCHES_OFF64_T. */ |
25 | #ifndef __OFF_T_MATCHES_OFF64_T | |
26 | ||
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27 | /* lockf is a simplified interface to fcntl's locking facilities. */ |
28 | ||
29 | int | |
30 | lockf64 (int fd, int cmd, off64_t len64) | |
31 | { | |
32 | struct flock fl; | |
33 | off_t len = (off_t) len64; | |
34 | ||
35 | if (len64 != (off64_t) len) | |
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36 | { |
37 | /* We can't represent the length. */ | |
38 | __set_errno (EOVERFLOW); | |
39 | return -1; | |
40 | } | |
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41 | |
42 | memset ((char *) &fl, '\0', sizeof (fl)); | |
43 | ||
44 | /* lockf is always relative to the current file position. */ | |
45 | fl.l_whence = SEEK_CUR; | |
46 | fl.l_start = 0; | |
47 | fl.l_len = len; | |
48 | ||
49 | switch (cmd) | |
50 | { | |
51 | case F_TEST: | |
52 | /* Test the lock: return 0 if FD is unlocked or locked by this process; | |
53 | return -1, set errno to EACCES, if another process holds the lock. */ | |
35b99c57 | 54 | fl.l_type = F_RDLCK; |
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55 | if (__fcntl (fd, F_GETLK, &fl) < 0) |
56 | return -1; | |
57 | if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ()) | |
58 | return 0; | |
59 | __set_errno (EACCES); | |
60 | return -1; | |
61 | ||
62 | case F_ULOCK: | |
63 | fl.l_type = F_UNLCK; | |
64 | cmd = F_SETLK; | |
65 | break; | |
66 | case F_LOCK: | |
67 | fl.l_type = F_WRLCK; | |
68 | cmd = F_SETLKW; | |
69 | break; | |
70 | case F_TLOCK: | |
71 | fl.l_type = F_WRLCK; | |
72 | cmd = F_SETLK; | |
73 | break; | |
74 | ||
75 | default: | |
76 | __set_errno (EINVAL); | |
77 | return -1; | |
78 | } | |
79 | ||
80 | return __fcntl (fd, cmd, &fl); | |
81 | } | |
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82 | |
83 | #endif |