Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ad36d282 authored by Richard Guy Briggs's avatar Richard Guy Briggs Committed by Eric Paris
Browse files

pid: get pid_t ppid of task in init_pid_ns 



Added the functions task_ppid_nr_ns() and task_ppid_nr() to abstract the lookup
of the PPID (real_parent's pid_t) of a process, including rcu locking, in the
arbitrary and init_pid_ns.
This provides an alternative to sys_getppid(), which is relative to the child
process' pid namespace.

(informed by ebiederman's 6c621b7e)
Cc: stable@vger.kernel.org
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarRichard Guy Briggs <rgb@redhat.com>
parent 4a3eb726

include/linux/sched.h

+19 −1
Original line number Diff line number Diff line
@@ -1561,6 +1561,24 @@ static inline pid_t task_tgid_vnr(struct task_struct *tsk) 
}





static int pid_alive(const struct task_struct *p);

static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns)

{

	pid_t pid = 0;



	rcu_read_lock();

	if (pid_alive(tsk))

		pid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns);

	rcu_read_unlock();



	return pid;

}



static inline pid_t task_ppid_nr(const struct task_struct *tsk)

{

	return task_ppid_nr_ns(tsk, &init_pid_ns);

}



static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk,

					struct pid_namespace *ns)

{
@@ -1600,7 +1618,7 @@ static inline pid_t task_pgrp_nr(struct task_struct *tsk) 
 *

 * Return: 1 if the process is alive. 0 otherwise.

 */

static inline int pid_alive(struct task_struct *p)

static inline int pid_alive(const struct task_struct *p)

{

	return p->pids[PIDTYPE_PID].pid != NULL;

}