| From ad36d28293936b03d6b7996e9d6aadfd73c0eb08 Mon Sep 17 00:00:00 2001 |
| From: Richard Guy Briggs <rgb@redhat.com> |
| Date: Thu, 15 Aug 2013 18:05:12 -0400 |
| Subject: pid: get pid_t ppid of task in init_pid_ns |
| |
| From: Richard Guy Briggs <rgb@redhat.com> |
| |
| commit ad36d28293936b03d6b7996e9d6aadfd73c0eb08 upstream. |
| |
| 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: Eric W. Biederman <ebiederm@xmission.com> |
| Signed-off-by: Richard Guy Briggs <rgb@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| include/linux/sched.h | 20 +++++++++++++++++++- |
| 1 file changed, 19 insertions(+), 1 deletion(-) |
| |
| --- a/include/linux/sched.h |
| +++ b/include/linux/sched.h |
| @@ -1688,6 +1688,24 @@ static inline pid_t task_tgid_vnr(struct |
| } |
| |
| |
| +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) |
| { |
| @@ -1727,7 +1745,7 @@ static inline pid_t task_pgrp_nr(struct |
| * |
| * 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; |
| } |