$lock = fopen('/path/to/pid', 'c+');
if (!flock($lock, LOCK_EX | LOCK_NB)) {
die('already running');
}
switch ($pid = pcntl_fork()) {
case -1:
die('unable to fork');
case 0: // this is the child process
break;
default: // otherwise this is the parent process
fseek($lock, 0);
ftruncate($lock, 0);
fwrite($lock, $pid);
fflush($lock);
exit;
}
if (posix_setsid() === -1) {
die('could not setsid');
}
fclose(STDIN);
fclose(STDOUT);
fclose(STDERR);
$stdIn = fopen('/dev/null', 'r'); // set fd/0
$stdOut = fopen('/dev/null', 'w'); // set fd/1
$stdErr = fopen('php://stdout', 'w'); // a hack to duplicate fd/1 to 2
pcntl_signal(SIGTSTP, SIG_IGN);
pcntl_signal(SIGTTOU, SIG_IGN);
pcntl_signal(SIGTTIN, SIG_IGN);
pcntl_signal(SIGHUP, SIG_IGN);
// do some staff
// to kill the proccess
$lock = fopen(‘/path/to/pid’, ‘c+’);
if (flock($lock, LOCK_EX | LOCK_NB)) {
die(‘process not running’);
}
$pid = fgets($lock);
posix_kill($pid, SIGTERM);