diff options
| author | Richard Guy Briggs <rgb@redhat.com> | 2013-08-15 18:05:12 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-04-30 16:23:23 +0100 |
| commit | 0ce844aea64b8bff202676fd87f2932b3eb35b83 (patch) | |
| tree | c13d0fce29ad4e84397a202af323d38c371f51b9 /include | |
| parent | 209e1b813d01a0a6fe12cecc9e15dbf40cdf12ad (diff) | |
pid: get pid_t ppid of task in init_pid_ns
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: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched.h | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index c17fdfbd323f..cb34ff42e4c3 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1690,6 +1690,24 @@ 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) { @@ -1727,7 +1745,7 @@ static inline pid_t task_pgrp_nr(struct task_struct *tsk) * If pid_alive fails, then pointers within the task structure * can be stale and must not be dereferenced. */ -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; } |