Function sys_setpgid

components/lwp/lwp_pgrp.c:323–478

* setpgid() sets the PGID of the process specified by pid to pgid. * If pid is zero, then the process ID of the calling process is used. * If pgid is zero, then the PGID of the process specified by pid is made the same as its process ID. * If setpgid() is used to move a process from one process group to another (as is done by some shells when * creating pipelines), both process groups

 *      match the session ID of the joining process.
 */
sysret_t sys_setpgid(pid_t pid, pid_t pgid)
{
    rt_lwp_t process, self_process;
    pid_t sid;
    rt_processgroup_t group;
    rt_session_t session;
    sysret_t err = 0;

    if (pgid == 0)
    {
        pgid = pid;
    }
    if (pgid < 0)
    {
        return -EINVAL;
    }

    self_process = lwp_self();

    if (pid == 0)
    {
        pid = self_process->pid;
        process = self_process;
    }
    else
    {
        lwp_pid_lock_take();
        process = lwp_from_pid_locked(pid);
        lwp_pid_lock_release();

        if (process == RT_NULL)
        {
            return -ESRCH;
        }
    }

    LWP_LOCK(process);

    if (process->parent == self_process)
    {
        /**
         * change the process group ID of one of the children of the calling process and the child was in
         *  a different session
         */
        if (lwp_sid_get_byprocess(process) != lwp_sid_get_byprocess(self_process))
        {
            err = -EPERM;
            LWP_UNLOCK(process);
            goto exit;
        }
        /**
         * An attempt was made to change the process group ID of one of the children of the calling process
         *  and the child had already performed an execve(2)
         */
        if (process->did_exec)
        {
            err = -EACCES;
            LWP_UNLOCK(process);