Added the functions
task_ppid()
task_ppid_nr_ns()
task_ppid_nr_init_ns()
to safely abstract the lookup of the PPID (real_parent's tgid) of a process,
including rcu locking, in any required pid namespace. This provides an
alternative to sys_getppid(), which is relative to the child process' pid
namespace.
(informed by ebiederman's 6c621b7e)
Cc: sta...@vger.kernel.org
Cc: Eric W. Biederman <ebied...@xmission.com>
Signed-off-by: Richard Guy Briggs <r...@redhat.com>
---
include/linux/sched.h | 23 +++++++++++++++++++++++
1 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d722490..ec04090 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1448,6 +1448,11 @@ static inline struct pid *task_session(struct
task_struct *task)
return task->group_leader->pids[PIDTYPE_SID].pid;
}
+static inline struct pid *task_ppid(struct task_struct *task)
+{
+ return task_tgid(rcu_dereference(current->real_parent));
+}
+
struct pid_namespace;
/*
@@ -1496,6 +1501,24 @@ static inline pid_t task_tgid_vnr(struct task_struct
*tsk)
}
+static inline pid_t task_ppid_nr_ns(struct task_struct *tsk,
+ struct pid_namespace *ns)
+{
+ pid_t pid;
+
+ rcu_read_lock();
+ pid = pid_nr_ns(task_ppid(current), ns);
+ rcu_read_unlock();
+
+ return pid;
+}
+
+static inline pid_t task_ppid_nr_init_ns(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)
{
--
1.7.1
--
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