From patchwork Tue Apr 22 20:13:46 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 341586 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id E1D16140083; Wed, 23 Apr 2014 06:28:04 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1WchIP-00059S-C8; Tue, 22 Apr 2014 20:28:01 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1WchF5-0003JD-1H for kernel-team@lists.ubuntu.com; Tue, 22 Apr 2014 20:24:35 +0000 Received: from c-67-160-228-185.hsd1.ca.comcast.net ([67.160.228.185] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1Wch5x-00058P-MG; Tue, 22 Apr 2014 20:15:10 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1Wch5v-0003Tz-Rl; Tue, 22 Apr 2014 13:15:07 -0700 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.8 088/133] pid: get pid_t ppid of task in init_pid_ns Date: Tue, 22 Apr 2014 13:13:46 -0700 Message-Id: <1398197671-12786-89-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1398197671-12786-1-git-send-email-kamal@canonical.com> References: <1398197671-12786-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Cc: Richard Guy Briggs , Kamal Mostafa , "Eric W. Biederman" X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.8.13.22 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Richard Guy Briggs 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 Signed-off-by: Richard Guy Briggs Signed-off-by: Kamal Mostafa --- include/linux/sched.h | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 87f0503..ee686ba 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1727,6 +1727,24 @@ 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) { @@ -1764,7 +1782,7 @@ 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; }