Merge branch 'master' into upstream

[pandora-kernel.git] / kernel / sys.c

diff --git a/kernel/sys.c b/kernel/sys.c
index 7ef7f60..0b6ec0e 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1372,18 +1372,29 @@ asmlinkage long sys_getsid(pid_t pid)
 asmlinkage long sys_setsid(void)
 {
        struct task_struct *group_leader = current->group_leader;
-       struct pid *pid;
+       pid_t session;
        int err = -EPERM;
 
        mutex_lock(&tty_mutex);
        write_lock_irq(&tasklist_lock);
 
-       pid = find_pid(PIDTYPE_PGID, group_leader->pid);
-       if (pid)
+       /* Fail if I am already a session leader */
+       if (group_leader->signal->leader)
+               goto out;
+
+       session = group_leader->pid;
+       /* Fail if a process group id already exists that equals the
+        * proposed session id.
+        *
+        * Don't check if session id == 1 because kernel threads use this
+        * session id and so the check will always fail and make it so
+        * init cannot successfully call setsid.
+        */
+       if (session > 1 && find_task_by_pid_type(PIDTYPE_PGID, session))
                goto out;
 
        group_leader->signal->leader = 1;
-       __set_special_pids(group_leader->pid, group_leader->pid);
+       __set_special_pids(session, session);
        group_leader->signal->tty = NULL;
        group_leader->signal->tty_old_pgrp = 0;
        err = process_group(group_leader);