forked from tmm1/matzruby
/
flock.c
135 lines (119 loc) · 2.63 KB
/
flock.c
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#include "config.h"
#if defined _WIN32
#elif defined HAVE_FCNTL && defined HAVE_FCNTL_H
/* These are the flock() constants. Since this sytems doesn't have
flock(), the values of the constants are probably not available.
*/
# ifndef LOCK_SH
# define LOCK_SH 1
# endif
# ifndef LOCK_EX
# define LOCK_EX 2
# endif
# ifndef LOCK_NB
# define LOCK_NB 4
# endif
# ifndef LOCK_UN
# define LOCK_UN 8
# endif
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
int
flock(fd, operation)
int fd;
int operation;
{
struct flock lock;
switch (operation & ~LOCK_NB) {
case LOCK_SH:
lock.l_type = F_RDLCK;
break;
case LOCK_EX:
lock.l_type = F_WRLCK;
break;
case LOCK_UN:
lock.l_type = F_UNLCK;
break;
default:
errno = EINVAL;
return -1;
}
lock.l_whence = SEEK_SET;
lock.l_start = lock.l_len = 0L;
return fcntl(fd, (operation & LOCK_NB) ? F_SETLK : F_SETLKW, &lock);
}
#elif defined(HAVE_LOCKF)
#include <unistd.h>
#include <errno.h>
/* Emulate flock() with lockf() or fcntl(). This is just to increase
portability of scripts. The calls might not be completely
interchangeable. What's really needed is a good file
locking module.
*/
# ifndef F_ULOCK
# define F_ULOCK 0 /* Unlock a previously locked region */
# endif
# ifndef F_LOCK
# define F_LOCK 1 /* Lock a region for exclusive use */
# endif
# ifndef F_TLOCK
# define F_TLOCK 2 /* Test and lock a region for exclusive use */
# endif
# ifndef F_TEST
# define F_TEST 3 /* Test a region for other processes locks */
# endif
/* These are the flock() constants. Since this sytems doesn't have
flock(), the values of the constants are probably not available.
*/
# ifndef LOCK_SH
# define LOCK_SH 1
# endif
# ifndef LOCK_EX
# define LOCK_EX 2
# endif
# ifndef LOCK_NB
# define LOCK_NB 4
# endif
# ifndef LOCK_UN
# define LOCK_UN 8
# endif
int
flock(fd, operation)
int fd;
int operation;
{
switch (operation) {
/* LOCK_SH - get a shared lock */
case LOCK_SH:
rb_notimplement();
return -1;
/* LOCK_EX - get an exclusive lock */
case LOCK_EX:
return lockf (fd, F_LOCK, 0);
/* LOCK_SH|LOCK_NB - get a non-blocking shared lock */
case LOCK_SH|LOCK_NB:
rb_notimplement();
return -1;
/* LOCK_EX|LOCK_NB - get a non-blocking exclusive lock */
case LOCK_EX|LOCK_NB:
return lockf (fd, F_TLOCK, 0);
/* LOCK_UN - unlock */
case LOCK_UN:
return lockf (fd, F_ULOCK, 0);
/* Default - can't decipher operation */
default:
errno = EINVAL;
return -1;
}
}
#else
int
flock(fd, operation)
int fd;
int operation;
{
rb_notimplement();
return -1;
}
#endif