Process groups are now reference-counted. Processes in a group as well

as the death entries of a deceased processes that were in this group
and have not yet been reaped hold references to the group, so that it
won't be deleted until the group is empty and all gone group members
have been reaped. This fixes #1799 at last.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24335 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/thread.cpp

@@ -1192,7 +1192,6 @@ thread_exit(void)
 {
 	cpu_status state;
 	struct thread *thread = thread_get_current_thread();
-	struct process_group *freeGroup = NULL;
 	struct team *team = thread->team;
 	thread_id parentID = -1;
 	bool deleteTeam = false;
@@ -1261,12 +1260,7 @@ thread_exit(void)
 			team->job_control_entry = NULL;
 
 			if (death != NULL) {
-				death->team = NULL;
-				death->group_id = team->group_id;
-				death->thread = thread->id;
-				death->status = thread->exit.status;
-				death->reason = thread->exit.reason;
-				death->signal = thread->exit.signal;
+				death->InitDeadState();
 
 				// team_set_job_control_state() already moved our entry
 				// into the parent's list. We just check the soft limit of
@@ -1281,7 +1275,7 @@ thread_exit(void)
 			} else
 				RELEASE_THREAD_LOCK();
 
-			team_remove_team(team, &freeGroup);
+			team_remove_team(team);
 
 			send_signal_etc(parentID, SIGCHLD,
 				SIGNAL_FLAG_TEAMS_LOCKED | B_DO_NOT_RESCHEDULE);
@@ -1324,15 +1318,6 @@ thread_exit(void)
 
 	// delete the team if we're its main thread
 	if (deleteTeam) {
-		// TODO: Deleting the process group is actually a problem. According to
-		// the POSIX standard the process should become a zombie and live on
-		// until it is reaped. Hence the process group would continue to exist
-		// for that time as well. That is moving processes to it (setpgid())
-		// should work. This can actually happen e.g. when executing something
-		// like "echo foobar | wc" in the shell. The built-in "echo" could
-		// exit() even before setpgid() has been invoked for the "wc" child.
-		// Cf. bug #1799.
-		team_delete_process_group(freeGroup);
 		team_delete_team(team);
 
 		// we need to delete any death entry that made it to here