Revision 22525,
1.1 KB
checked in by rbasch, 18 years ago
(diff) |
Open the lock file read-only, since we are not setting a lock.
Also remove the extraneous mode parameter in the open().
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Rev | Line | |
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[22492] | 1 | #include <stdio.h> |
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| 2 | #include <sys/types.h> |
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| 3 | #include <sys/stat.h> |
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| 4 | #include <unistd.h> |
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| 5 | #include <fcntl.h> |
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| 6 | #include <string.h> |
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| 7 | #include <errno.h> |
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| 8 | |
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| 9 | int main(int argc, char **argv) |
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| 10 | { |
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| 11 | char *progname, *filename; |
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| 12 | int fd; |
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| 13 | struct flock lock; |
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| 14 | |
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| 15 | progname = argv[0]; |
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| 16 | if (argc != 2) |
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| 17 | { |
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| 18 | fprintf(stderr, "%s: Usage: %s <lock_file>\n", progname, progname); |
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| 19 | return 4; |
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| 20 | } |
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| 21 | filename = argv[1]; |
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| 22 | |
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| 23 | /* Open the file. */ |
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[22525] | 24 | fd = open(filename, O_RDONLY); |
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[22492] | 25 | if (fd == -1) |
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| 26 | { |
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| 27 | fprintf(stderr, "%s: Cannot open %s: %s\n", progname, filename, |
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| 28 | strerror(errno)); |
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| 29 | return 3; |
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| 30 | } |
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| 31 | |
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| 32 | /* See if there is a write lock on the file. */ |
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| 33 | lock.l_type = F_WRLCK; |
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| 34 | lock.l_whence = SEEK_SET; |
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| 35 | lock.l_start = 0; |
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| 36 | lock.l_len = 0; |
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| 37 | if (fcntl(fd, F_GETLK, &lock) == -1) |
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| 38 | { |
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| 39 | fprintf(stderr, "%s: Cannot get the lock for %s: %s\n", progname, |
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| 40 | filename, strerror(errno)); |
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| 41 | return 3; |
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| 42 | } |
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| 43 | close(fd); |
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| 44 | if (lock.l_type != F_UNLCK) |
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| 45 | { |
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| 46 | /* The file is locked; print the PID of the locking process. */ |
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| 47 | printf("%ld\n", (long) lock.l_pid); |
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| 48 | return 2; |
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| 49 | } |
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| 50 | return 0; |
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| 51 | } |
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