[PATCH] setpgid: should work for sub-threads
setpgid(0, pgid) or setpgid(forked_child_pid, pgid) does not work unless
the calling process is a thread_group_leader().
'man setpgid' does not tell anything about that, so I consider this
behaviour is a bug.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Oren Laadan <orenl@cs.columbia.edu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/sys.c b/kernel/sys.c
index d8e49e6..43e5572 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1090,10 +1090,11 @@
asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
{
struct task_struct *p;
+ struct task_struct *group_leader = current->group_leader;
int err = -EINVAL;
if (!pid)
- pid = current->pid;
+ pid = group_leader->pid;
if (!pgid)
pgid = pid;
if (pgid < 0)
@@ -1113,16 +1114,16 @@
if (!thread_group_leader(p))
goto out;
- if (p->parent == current || p->real_parent == current) {
+ if (p->parent == current || p->real_parent == group_leader) {
err = -EPERM;
- if (p->signal->session != current->signal->session)
+ if (p->signal->session != group_leader->signal->session)
goto out;
err = -EACCES;
if (p->did_exec)
goto out;
} else {
err = -ESRCH;
- if (p != current)
+ if (p != group_leader)
goto out;
}
@@ -1134,7 +1135,7 @@
struct task_struct *p;
do_each_task_pid(pgid, PIDTYPE_PGID, p) {
- if (p->signal->session == current->signal->session)
+ if (p->signal->session == group_leader->signal->session)
goto ok_pgid;
} while_each_task_pid(pgid, PIDTYPE_PGID, p);
goto out;