Function procdesc_close

freebsd/kern/sys_procdesc.c:350–421

* procdesc_close() - last close on a process descriptor. If the process is * still running, terminate with SIGKILL (unless PDF_DAEMON is set) and let * its reaper clean up the mess; if not, we have to clean up the zombie * ourselves. */

 * ourselves.
 */
static int
procdesc_close(struct file *fp, struct thread *td)
{
	struct procdesc *pd;
	struct proc *p;

	KASSERT(fp->f_type == DTYPE_PROCDESC, ("procdesc_close: !procdesc"));

	pd = fp->f_data;
	fp->f_ops = &badfileops;
	fp->f_data = NULL;

	sx_xlock(&proctree_lock);
	PROCDESC_LOCK(pd);
	pd->pd_flags |= PDF_CLOSED;
	PROCDESC_UNLOCK(pd);
	p = pd->pd_proc;
	if (p == NULL) {
		/*
		 * This is the case where process' exit status was already
		 * collected and procdesc_reap() was already called.
		 */
		sx_xunlock(&proctree_lock);
	} else {
		PROC_LOCK(p);
		AUDIT_ARG_PROCESS(p);
		if (p->p_state == PRS_ZOMBIE) {
			/*
			 * If the process is already dead and just awaiting
			 * reaping, do that now.  This will release the
			 * process's reference to the process descriptor when it
			 * calls back into procdesc_reap().
			 */
			proc_reap(curthread, p, NULL, 0);
		} else {
			/*
			 * If the process is not yet dead, we need to kill it,
			 * but we can't wait around synchronously for it to go
			 * away, as that path leads to madness (and deadlocks).
			 * First, detach the process from its descriptor so that
			 * its exit status will be reported normally.
			 */
			pd->pd_proc = NULL;
			p->p_procdesc = NULL;
			procdesc_free(pd);

			/*
			 * Next, reparent it to its reaper (usually init(8)) so
			 * that there's someone to pick up the pieces; finally,
			 * terminate with prejudice.
			 */
			p->p_sigparent = SIGCHLD;
			if ((p->p_flag & P_TRACED) == 0) {
				proc_reparent(p, p->p_reaper, true);
			} else {
				proc_clear_orphan(p);
				p->p_oppid = p->p_reaper->p_pid;
				proc_add_orphan(p, p->p_reaper);