pid: get pid_t ppid of task in init_pid_ns (ad36d282) · Commits · 戴 / test

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:

Richard Guy Briggs <rgb@redhat.com>

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;
		}

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