The child process from PHP pcntl_fork used a semaphore to exit unsuccessfully.

The test code used is as follows:

<code><?php 

cli_set_process_title('test-semaphore');

$semid = sem_get(ftok(__FILE__, 'x'), 1);

function daemonize()
{
    umask(0);
    $pid = pcntl_fork();
    if (-1 === $pid) {
        throw new Exception('fork fail');
    } elseif ($pid > 0) {
        // 这里父进程可以退出
        exit(0);
    }
    
    if (-1 === posix_setsid()) {
        throw new Exception("setsid fail");
    }

    // 从这里开始信号量不删除就无法退出
    $pid = pcntl_fork();
    if (-1 === $pid) {
        throw new Exception("fork fail");
    } elseif (0 !== $pid) {
        // 子进程退出不成功
        exit(0);
    }
}

daemonize();
// 孙进程退出不成功

</code>

Verify on the command line: ps aux | grep test-semaphore. You can see that the process status is normal (sleep state)

<code>xxx    115581  0.0  0.2 388532  7760 ?        Ss   11:33   0:00 test-semaphore
xxx    115582  0.0  0.1 388532  7584 ?        S    11:33   0:00 test-semaphore
</code>

Use sem_remove() or ipcrm command anywhere in the code to exit the process.

Reply content:

The test code used is as follows:

<code><?php 

cli_set_process_title('test-semaphore');

$semid = sem_get(ftok(__FILE__, 'x'), 1);

function daemonize()
{
    umask(0);
    $pid = pcntl_fork();
    if (-1 === $pid) {
        throw new Exception('fork fail');
    } elseif ($pid > 0) {
        // 这里父进程可以退出
        exit(0);
    }
    
    if (-1 === posix_setsid()) {
        throw new Exception("setsid fail");
    }

    // 从这里开始信号量不删除就无法退出
    $pid = pcntl_fork();
    if (-1 === $pid) {
        throw new Exception("fork fail");
    } elseif (0 !== $pid) {
        // 子进程退出不成功
        exit(0);
    }
}

daemonize();
// 孙进程退出不成功

</code>

Verify on the command line: ps aux | grep test-semaphore. You can see that the process status is normal (sleep state)

<code>xxx    115581  0.0  0.2 388532  7760 ?        Ss   11:33   0:00 test-semaphore
xxx    115582  0.0  0.1 388532  7584 ?        S    11:33   0:00 test-semaphore
</code>

Use sem_remove() or ipcrm command anywhere in the code to exit the process.