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#include "gup.h"
static int locked = FALSE; /* do we have a lock? */
/* Take a lock in the current directory */
int lockit(void)
{
int fd;
#ifdef USE_DOTLOCK
int count;
#endif
#ifdef USE_FLOCK
/* more style points that FILE_LOCK, if it succeeds */
if ((fd = open(".", O_RDONLY)) >= 0) {
if (flock(fd, LOCK_EX) == 0) { /* lock was successful */
locked = TRUE;
return TRUE;
/* one fd is used here and never closed */
}
logit(L_LOG, "WARNING: flock failed");
close(fd); /* flock failed, so don't hold on */
}
#endif
#ifdef USE_DOTLOCK
for (count = 0; count < MAX_LOCK_SLEEP_COUNT; count++) {
fd = open("LOCK", O_CREAT | O_WRONLY | O_EXCL, 0644);
if (fd >= 0 || errno != EEXIST)
break;
sleep(LOCK_SLEEP);
}
if (fd < 0 && errno == EEXIST) {
fd = open("LOCK", O_CREAT | O_WRONLY);
if (fd >= 0)
logit(L_LOG, "WARNING: Trashed pre-existing lock");
}
if (fd < 0)
gupout(1, "Could not open lock file");
/* Take the lock and write out our pid if the lock works */
{
char buf[32];
int res;
sprintf(buf, "%5d\n", getpid());
res = write(fd, buf, strlen(buf));
if (res < 0)
gupout(1, "Could not write lock file");
close(fd);
locked = TRUE;
return TRUE;
}
#endif
return FALSE;
}
/* Release the lock created by lockit() */
void unlockit(void)
{
if (locked) {
#ifdef USE_FLOCK
int fd;
#endif
locked = FALSE;
#ifdef USE_FLOCK
if ((fd = open(".", O_RDONLY)) >= 0) {
if (flock(fd, LOCK_UN) == 0) {
close(fd);
return;
}
logit(L_LOG, "WARNING: unflock failed");
close(fd); /* flock failed, so don't hold on */
}
#endif
#ifdef USE_DOTLOCK
if (unlink("LOCK") < 0) {
if (errno == ENOENT)
logit(L_LOG, "WARNING: Could not delete lock file "
"'cos it doesn't exist!");
else
logit(L_LOG, "ERROR: Could not delete lock file");
}
#endif
}
}
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