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91 lines
1.8 KiB
C
91 lines
1.8 KiB
C
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#include "config.h"
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#if defined(HAVE_LOCKF)
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#include <unistd.h>
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#include <errno.h>
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/* Emulate flock() with lockf() or fcntl(). This is just to increase
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portability of scripts. The calls might not be completely
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interchangeable. What's really needed is a good file
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locking module.
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*/
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# ifndef F_ULOCK
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# define F_ULOCK 0 /* Unlock a previously locked region */
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# endif
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# ifndef F_LOCK
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# define F_LOCK 1 /* Lock a region for exclusive use */
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# endif
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# ifndef F_TLOCK
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# define F_TLOCK 2 /* Test and lock a region for exclusive use */
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# endif
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# ifndef F_TEST
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# define F_TEST 3 /* Test a region for other processes locks */
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# endif
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/* These are the flock() constants. Since this sytems doesn't have
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flock(), the values of the constants are probably not available.
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*/
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# ifndef LOCK_SH
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# define LOCK_SH 1
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# endif
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# ifndef LOCK_EX
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# define LOCK_EX 2
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# endif
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# ifndef LOCK_NB
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# define LOCK_NB 4
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# endif
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# ifndef LOCK_UN
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# define LOCK_UN 8
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# endif
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int
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flock(fd, operation)
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int fd;
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int operation;
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{
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int i;
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switch (operation) {
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/* LOCK_SH - get a shared lock */
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case LOCK_SH:
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/* LOCK_EX - get an exclusive lock */
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case LOCK_EX:
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i = lockf (fd, F_LOCK, 0);
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break;
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/* LOCK_SH|LOCK_NB - get a non-blocking shared lock */
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case LOCK_SH|LOCK_NB:
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/* LOCK_EX|LOCK_NB - get a non-blocking exclusive lock */
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case LOCK_EX|LOCK_NB:
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i = lockf (fd, F_TLOCK, 0);
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if (i == -1)
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if ((errno == EAGAIN) || (errno == EACCES))
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errno = EWOULDBLOCK;
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break;
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/* LOCK_UN - unlock */
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case LOCK_UN:
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i = lockf (fd, F_ULOCK, 0);
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break;
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/* Default - can't decipher operation */
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default:
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i = -1;
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errno = EINVAL;
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break;
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}
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return i;
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}
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#else
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int
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flock(fd, operation)
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int fd;
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int operation;
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{
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rb_notimplement();
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return -1;
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}
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#endif
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