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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 <signal.h>
#include <sys/time.h>
#include <sys/stat.h>
#include "alsactl.h"
#define PATH_SIZE 512
static int alarm_flag;
static void signal_handler_alarm(int sig)
{
alarm_flag = 1;
}
static int state_lock_(const char *lock_file, int lock, int timeout, int _fd)
{
int fd = -1, err = 0;
struct flock lck;
struct stat st;
char lcktxt[14];
struct sigaction sig_alarm, sig_alarm_orig;
struct itimerval itv;
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", "");
fd = _fd;
}
while (fd < 0 && timeout-- > 0) {
fd = open(lock_file, O_RDWR);
if (!lock && fd < 0) {
err = -EIO;
goto out;
}
if (fd < 0) {
fd = open(lock_file, O_RDWR|O_CREAT|O_EXCL, 0644);
if (fd < 0) {
if (errno == EBUSY || errno == EAGAIN) {
sleep(1);
continue;
}
if (errno == EEXIST) {
fd = open(lock_file, O_RDWR);
if (fd >= 0)
break;
}
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 || !lock) {
if (write(fd, lcktxt, 11) != 11) {
err = -EIO;
goto out;
}
if (lock && lseek(fd, 0, SEEK_SET)) {
err = -errno;
goto out;
}
}
alarm_flag = 0;
memset(&sig_alarm, 0, sizeof(sig_alarm));
sigemptyset(&sig_alarm.sa_mask);
sig_alarm.sa_handler = signal_handler_alarm;
if (sigaction(SIGALRM, &sig_alarm, &sig_alarm_orig) < 0) {
err = -ENXIO;
goto out;
}
memset(&itv, 0, sizeof(itv));
itv.it_value.tv_sec = timeout;
if (setitimer(ITIMER_REAL, &itv, NULL) < 0) {
err = -ENXIO;
sigaction(SIGALRM, &sig_alarm_orig, NULL);
goto out;
}
while (alarm_flag == 0) {
if (fcntl(fd, F_SETLKW, &lck) == 0)
break;
if (errno == EAGAIN || errno == ERESTART)
continue;
}
memset(&itv, 0, sizeof(itv));
setitimer(ITIMER_REAL, &itv, NULL);
sigaction(SIGALRM, &sig_alarm_orig, NULL);
if (alarm_flag) {
err = -EBUSY;
goto out;
}
if (lock) {
if (write(fd, lcktxt, 11) != 11) {
err = -EIO;
goto out;
}
return fd;
}
err = 0;
out:
if (fd >= 0)
close(fd);
return err;
}
static void state_lock_file(char *buf, size_t buflen)
{
if (lockfile[0] == '/')
snprintf(buf, buflen, "%s", lockfile);
else
snprintf(buf, buflen, "%s/%s", lockpath, lockfile);
}
int state_lock(const char *file, int timeout)
{
char fn[PATH_SIZE];
int err;
state_lock_file(fn, sizeof(fn));
err = state_lock_(fn, 1, timeout, -1);
if (err < 0)
error("file %s lock error: %s", file, strerror(-err));
return err;
}
int state_unlock(int _fd, const char *file)
{
char fn[PATH_SIZE];
int err;
state_lock_file(fn, sizeof(fn));
err = state_lock_(fn, 0, 10, _fd);
if (err < 0)
error("file %s unlock error: %s", file, strerror(-err));
return err;
}
static void card_lock_file(char *buf, size_t buflen, int card_number)
{
snprintf(buf, buflen, "%s/card%i.lock", lockpath, card_number);
}
int card_lock(int card_number, int timeout)
{
char fn[PATH_SIZE];
int err;
card_lock_file(fn, sizeof(fn), card_number);
err = state_lock_(fn, 1, timeout, -1);
if (err < 0)
error("card %d lock error: %s", card_number, strerror(-err));
return err;
}
int card_unlock(int _fd, int card_number)
{
char fn[PATH_SIZE];
int err;
card_lock_file(fn, sizeof(fn), card_number);
err = state_lock_(fn, 0, 10, _fd);
if (err < 0)
error("card %d unlock error: %s", card_number, strerror(-err));
return err;
}
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