summaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorRichard Guy Briggs <rgb@redhat.com>2013-08-15 18:05:12 -0400
committerBen Hutchings <ben@decadent.org.uk>2014-04-30 16:23:23 +0100
commit0ce844aea64b8bff202676fd87f2932b3eb35b83 (patch)
treec13d0fce29ad4e84397a202af323d38c371f51b9 /include
parent209e1b813d01a0a6fe12cecc9e15dbf40cdf12ad (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.h20
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;
}