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/*
* Advanced Linux Sound Architecture Control Program
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "aconfig.h"
#include "version.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/stat.h>
#include "alsactl.h"
static int state_lock_(const char *file, int lock, int timeout)
{
int fd = -1, err = 0;
struct flock lck;
struct stat st;
char lcktxt[12];
char *nfile = lockfile;
if (do_lock <= 0)
return 0;
lck.l_type = lock ? F_WRLCK : F_UNLCK;
lck.l_whence = SEEK_SET;
lck.l_start = 0;
lck.l_len = 11;
lck.l_pid = 0;
if (lock) {
snprintf(lcktxt, sizeof(lcktxt), "%10li\n", (long)getpid());
} else {
snprintf(lcktxt, sizeof(lcktxt), "%10s\n", "");
}
while (fd < 0 && timeout-- > 0) {
fd = open(nfile, O_RDWR);
if (fd < 0) {
fd = open(nfile, O_RDWR|O_CREAT|O_EXCL, 0644);
if (fd < 0) {
if (errno == EBUSY || errno == EAGAIN) {
sleep(1);
timeout--;
} else {
err = -errno;
goto out;
}
}
}
}
if (fd < 0 && timeout <= 0) {
err = -EBUSY;
goto out;
}
if (fstat(fd, &st) < 0) {
err = -errno;
goto out;
}
if (st.st_size != 11) {
if (write(fd, lcktxt, 11) != 11) {
err = -EIO;
goto out;
}
if (lseek(fd, 0, SEEK_SET)) {
err = -errno;
goto out;
}
}
while (timeout > 0) {
if (fcntl(fd, F_SETLK, &lck) < 0) {
sleep(1);
timeout--;
} else {
break;
}
}
if (timeout <= 0) {
err = -EBUSY;
goto out;
}
if (write(fd, lcktxt, 11) != 11) {
err = -EIO;
goto out;
}
out:
return err;
}
int state_lock(const char *file, int lock, int timeout)
{
int err;
err = state_lock_(file, lock, timeout);
if (err < 0)
error("file %s %slock error: %s", file,
lock ? "" : "un", strerror(-err));
return err;
}
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