[PATCH] add process_session() helper routine

Replace occurences of task->signal->session by a new process_session() helper
routine.

It will be useful for pid namespaces to abstract the session pid number.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 17 insertions, 16 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index fa0495e..8d289bf 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -193,14 +193,14 @@ int session_of_pgrp(int pgrp)
 
 	read_lock(&tasklist_lock);
 	do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
-		if (p->signal->session > 0) {
-			sid = p->signal->session;
+		if (process_session(p) > 0) {
+			sid = process_session(p);
 			goto out;
 		}
 	} while_each_task_pid(pgrp, PIDTYPE_PGID, p);
 	p = find_task_by_pid(pgrp);
 	if (p)
-		sid = p->signal->session;
+		sid = process_session(p);
 out:
 	read_unlock(&tasklist_lock);
 	
@@ -225,8 +225,8 @@ static int will_become_orphaned_pgrp(int pgrp, struct task_struct *ignored_task)
 				|| p->exit_state
 				|| is_init(p->real_parent))
 			continue;
-		if (process_group(p->real_parent) != pgrp
-			    && p->real_parent->signal->session == p->signal->session) {
+		if (process_group(p->real_parent) != pgrp &&
+		    process_session(p->real_parent) == process_session(p)) {
 			ret = 0;
 			break;
 		}
@@ -302,7 +302,7 @@ void __set_special_pids(pid_t session, pid_t pgrp)
 {
 	struct task_struct *curr = current->group_leader;
 
-	if (curr->signal->session != session) {
+	if (process_session(curr) != session) {
 		detach_pid(curr, PIDTYPE_SID);
 		curr->signal->session = session;
 		attach_pid(curr, PIDTYPE_SID, session);
@@ -647,10 +647,11 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
 	 * outside, so the child pgrp is now orphaned.
 	 */
 	if ((process_group(p) != process_group(father)) &&
-	    (p->signal->session == father->signal->session)) {
+	    (process_session(p) == process_session(father))) {
 		int pgrp = process_group(p);
 
-		if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
+		if (will_become_orphaned_pgrp(pgrp, NULL) &&
+		    has_stopped_jobs(pgrp)) {
 			__kill_pg_info(SIGHUP, SEND_SIG_PRIV, pgrp);
 			__kill_pg_info(SIGCONT, SEND_SIG_PRIV, pgrp);
 		}
@@ -784,7 +785,7 @@ static void exit_notify(struct task_struct *tsk)
 	t = tsk->real_parent;
 	
 	if ((process_group(t) != process_group(tsk)) &&
-	    (t->signal->session == tsk->signal->session) &&
+	    (process_session(t) == process_session(tsk)) &&
 	    will_become_orphaned_pgrp(process_group(tsk), tsk) &&
 	    has_stopped_jobs(process_group(tsk))) {
 		__kill_pg_info(SIGHUP, SEND_SIG_PRIV, process_group(tsk));
diff --git a/kernel/fork.c b/kernel/fork.c
index 5977078..298c4d6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1259,9 +1259,9 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 		if (thread_group_leader(p)) {
 			p->signal->tty = current->signal->tty;
 			p->signal->pgrp = process_group(current);
-			p->signal->session = current->signal->session;
+			p->signal->session = process_session(current);
 			attach_pid(p, PIDTYPE_PGID, process_group(p));
-			attach_pid(p, PIDTYPE_SID, p->signal->session);
+			attach_pid(p, PIDTYPE_SID, process_session(p));
 
 			list_add_tail_rcu(&p->tasks, &init_task.tasks);
 			__get_cpu_var(process_counts)++;
diff --git a/kernel/signal.c b/kernel/signal.c
index ec81def..9eac4db 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -583,7 +583,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
 	error = -EPERM;
 	if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
 	    && ((sig != SIGCONT) ||
-		(current->signal->session != t->signal->session))
+		(process_session(current) != process_session(t)))
 	    && (current->euid ^ t->suid) && (current->euid ^ t->uid)
 	    && (current->uid ^ t->suid) && (current->uid ^ t->uid)
 	    && !capable(CAP_KILL))
diff --git a/kernel/sys.c b/kernel/sys.c
index 1ac2d1c..4f9d23a 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1381,7 +1381,7 @@ asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 
 	if (p->real_parent == group_leader) {
 		err = -EPERM;
-		if (p->signal->session != group_leader->signal->session)
+		if (process_session(p) != process_session(group_leader))
 			goto out;
 		err = -EACCES;
 		if (p->did_exec)
@@ -1400,7 +1400,7 @@ asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 		struct task_struct *p;
 
 		do_each_task_pid(pgid, PIDTYPE_PGID, p) {
-			if (p->signal->session == group_leader->signal->session)
+			if (process_session(p) == process_session(group_leader))
 				goto ok_pgid;
 		} while_each_task_pid(pgid, PIDTYPE_PGID, p);
 		goto out;
@@ -1459,7 +1459,7 @@ asmlinkage long sys_getpgrp(void)
 asmlinkage long sys_getsid(pid_t pid)
 {
 	if (!pid)
-		return current->signal->session;
+		return process_session(current);
 	else {
 		int retval;
 		struct task_struct *p;
@@ -1471,7 +1471,7 @@ asmlinkage long sys_getsid(pid_t pid)
 		if (p) {
 			retval = security_task_getsid(p);
 			if (!retval)
-				retval = p->signal->session;
+				retval = process_session(p);
 		}
 		read_unlock(&tasklist_lock);
 		return retval;