Subject: [PATCH] Cleanup the pspace signal handling.
From: Eric W. Biederman <ebiederman@lnxi.com>
Date: 1130041663 -0600

---

 include/linux/pid.h   |    1 -
 include/linux/sched.h |    4 ++-
 kernel/exit.c         |    2 +-
 kernel/fork.c         |    1 +
 kernel/signal.c       |   57 +++++++++++++++++++++++++------------------------
 5 files changed, 33 insertions(+), 32 deletions(-)

bc95878a75e6cfb7723bd386b5c8eb69723ff299
diff --git a/include/linux/pid.h b/include/linux/pid.h
index 8a75e6c..460fee8 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -8,7 +8,6 @@ enum pid_type
 	PIDTYPE_TGID,
 	PIDTYPE_PGID,
 	PIDTYPE_SID,
-	PIDTYPE_PSPACE,
 	PIDTYPE_MAX
 };
 
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0b01c97..270e0b3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1016,8 +1016,8 @@ extern int send_sig_info(int, struct sig
 extern int send_group_sig_info(int, struct siginfo *, struct task_struct *);
 extern int force_sigsegv(int, struct task_struct *);
 extern int force_sig_info(int, struct siginfo *, struct task_struct *);
-extern int __kill_pspace_info(int sig, struct siginfo *info, pid_t pspaceid);
-extern int kill_pspace_info(int sig, struct siginfo *info, pid_t pspaceid);
+extern int __kill_pspace_info(int sig, struct siginfo *info, struct pspace *pspace);
+extern int kill_pspace_info(int sig, struct siginfo *info, struct pspace *pspace);
 extern int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp);
 extern int kill_pg_info(int, struct siginfo *, pid_t);
 extern int kill_proc_info(int, struct siginfo *, pid_t);
diff --git a/kernel/exit.c b/kernel/exit.c
index aa349bf..19068c5 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -745,7 +745,7 @@ static void exit_notify(struct task_stru
 	 */
 	if (pspace_leader(tsk)) {
 		tsk->sighand->action[SIGCHLD-1].sa.sa_handler = SIG_IGN;
-		__kill_pspace_info(SIGKILL, (void *)1, tsk->tgid);
+		__kill_pspace_info(SIGKILL, (void *)1, tsk->pspace);
 	}
 
 	/* Let father know we died 
diff --git a/kernel/fork.c b/kernel/fork.c
index 156359a..97aef76 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1146,6 +1146,7 @@ static task_t *copy_process(unsigned lon
 		p->signal->session = p->pid;
 		p->signal->tty = NULL;
 		p->signal->tty_old_pgrp = 0;
+		attach_pid(p, PIDTYPE_ALTPID, p->pid);
 	}
 	attach_pid(p, PIDTYPE_PID, p->pid);
 	attach_pid(p, PIDTYPE_TGID, p->tgid);
diff --git a/kernel/signal.c b/kernel/signal.c
index 4842b9e..32fcb92 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1145,44 +1145,48 @@ int group_send_sig_info(int sig, struct 
 }
 
 /*
- * kill_pspace_info() sends a signal to all processes in a process id space.
+ * kill_pspace_info() sends a signal to all processes in a process space.
  * This is what kill(-1, sig) does.
  */
 
-int __kill_pspace_info(int sig, struct siginfo *info, pid_t pspaceid)
+int __kill_pspace_info(int sig, struct siginfo *info, struct pspace *pspace)
 {
 	struct task_struct *p = NULL;
-	struct pspace *pspace;
-	pid_t min, max;
 	int retval = 0, count = 0;
 
-	p = find_task_by_pid_type(PIDTYPE_TGID, pspaceid);
-	if (!p || (p->tgid != (p->pspace->offset + 1)))
-		return -ESRCH;
-
-	pspace = p->pspace;
-	min = pspace->offset; 
-	max = pspace->offset + pspace->max;
-
 	for_each_process(p) {
-		if ((p != current->pspace->child_reaper) && (p->tgid != current->tgid) &&
-			(p->pid > min) && (p->pid < max))
-		{
-			int err = group_send_sig_info(sig, info, p);
-			++count;
-			if (err != -EPERM)
-				retval = err;
-		}
+		struct pspace *test;
+		int err;
+		/* Skip init */
+		if (pspace_leader(p))
+			continue;
+
+		/* Skip the sender of the signal */
+		if (p->tgid == current->tgid)
+			continue;
+
+		/* Skip processes outside the target process space */
+		test = p->pspace;
+		while(test && (test != pspace))
+			test = test->parent;
+		if (test != pspace)
+			continue;
+		
+		/* Finally it is a good process send the signal. */
+		err = group_send_sig_info(sig, info, p);
+		++count;
+		if (err != -EPERM)
+			retval = err;
 	}
 	return count ? retval : -ESRCH;
 }
 
-int kill_pspace_info(int sig, struct siginfo *info, pid_t pspaceid)
+int kill_pspace_info(int sig, struct siginfo *info, struct pspace *pspace)
 {
 	int retval;
 
 	read_lock(&tasklist_lock);
-	retval = __kill_pspace_info(sig, info, pspaceid);
+	retval = __kill_pspace_info(sig, info, pspace);
 	read_unlock(&tasklist_lock);
 
 	return retval;
@@ -1258,11 +1262,11 @@ static int kill_something_info(int sig, 
 
 		pid = pid_from_user(-pid);
 		read_lock(&tasklist_lock);
-		p = find_task_by_pid_type(PIDTYPE_TGID, pid);
-		if (likely(!p || (p->tgid != (p->pspace->offset + 1))))
+		p = find_task_by_pid(pid);
+		if (!p || !pspace_leader(p))
 			retval = __kill_pg_info(sig, info, pid);
 		else
-			retval = __kill_pspace_info(sig, info, pid);
+			retval = __kill_pspace_info(sig, info, p->pspace);
 		read_unlock(&tasklist_lock);
 		return retval;
 	} else {
@@ -1717,9 +1721,6 @@ finish_stop(int stop_count)
 		goto out;
 
 	read_lock(&tasklist_lock);
-	/* If init stops stop all of it's children */
-	if (pspace_leader(current)) 
-		__kill_pspace_info(SIGSTOP, (void *)1, current->tgid);
 	do_notify_parent_cldstop(current, to_self, CLD_STOPPED);
 	read_unlock(&tasklist_lock);
 
-- 
1.0.GIT