Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755623AbaJHJ4s (ORCPT ); Wed, 8 Oct 2014 05:56:48 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:11561 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1754992AbaJHJ4q convert rfc822-to-8bit (ORCPT ); Wed, 8 Oct 2014 05:56:46 -0400 X-IronPort-AV: E=Sophos;i="5.04,676,1406563200"; d="scan'208";a="36954194" From: Chen Hanxiao To: , CC: Serge Hallyn , "Eric W. Biederman" , Oleg Nesterov , David Howells , Richard Weinberger , Pavel Emelyanov , Vasiliy Kulikov , Mateusz Guzik Subject: [PATCHv4] procfs: show hierarchy of pid namespace Date: Wed, 8 Oct 2014 17:56:38 +0800 Message-ID: <1412762198-21825-1-git-send-email-chenhanxiao@cn.fujitsu.com> X-Mailer: git-send-email 1.9.0 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.167.226.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch will show the hierarchy of pid namespace by /proc/pidns_hierarchy like: [root@localhost ~]#cat /proc/pidns_hierarchy /proc/18060/ns/pid /proc/18102/ns/pid /proc/1534/ns/pid /proc/18060/ns/pid /proc/18102/ns/pid /proc/1600/ns/pid /proc/1550/ns/pid It shows the pid hierarchy below: init_pid_ns (not showed in /proc/pidns_hierarchy) │ ┌──────────────┐ ns1 ns2 │ │ /proc/1550/ns/pid /proc/18060/ns/pid │ │ ns3 │ /proc/18102/ns/pid │ ┌──────────┒ ns4 ns5 │ │ /proc/1534/ns/pid /proc/1600/ns/pid Every pid printed in pidns_hierarchy is the init pid of that pid ns level. Signed-off-by: Chen Hanxiao --- v4: simplify pid collection and do some performance optimizamtion fix another race issue. v3: fix a race issue and memory leak issue v2: use a procfs text file instead of dirs under /proc fs/proc/Kconfig | 6 ++ fs/proc/Makefile | 1 + fs/proc/pidns_hierarchy.c | 218 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 225 insertions(+) create mode 100644 fs/proc/pidns_hierarchy.c diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig index 2183fcf..4bb111c 100644 --- a/fs/proc/Kconfig +++ b/fs/proc/Kconfig @@ -71,3 +71,9 @@ config PROC_PAGE_MONITOR /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap, /proc/kpagecount, and /proc/kpageflags. Disabling these interfaces will reduce the size of the kernel by approximately 4kb. + +config PROC_PID_HIERARCHY + bool "Enable /proc/pidns_hierarchy support" if EXPERT + depends on PROC_FS + help + Show pid namespace hierarchy information diff --git a/fs/proc/Makefile b/fs/proc/Makefile index 7151ea4..33e384b 100644 --- a/fs/proc/Makefile +++ b/fs/proc/Makefile @@ -30,3 +30,4 @@ proc-$(CONFIG_PROC_KCORE) += kcore.o proc-$(CONFIG_PROC_VMCORE) += vmcore.o proc-$(CONFIG_PRINTK) += kmsg.o proc-$(CONFIG_PROC_PAGE_MONITOR) += page.o +proc-$(CONFIG_PROC_PID_HIERARCHY) += pidns_hierarchy.o diff --git a/fs/proc/pidns_hierarchy.c b/fs/proc/pidns_hierarchy.c new file mode 100644 index 0000000..621661b --- /dev/null +++ b/fs/proc/pidns_hierarchy.c @@ -0,0 +1,218 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * /proc/pidns_hierarchy + * + * show the hierarchy of pid namespace + */ + +#define NS_HIERARCHY "pidns_hierarchy" + +static LIST_HEAD(pidns_list); +static LIST_HEAD(pidns_tree); +static DEFINE_MUTEX(pidns_list_lock); + +/* list for host pid collection */ +struct pidns_list { + struct list_head list; + struct pid *pid; +}; + +static void free_pidns_list(struct list_head *head) +{ + struct pidns_list *tmp, *pos; + + list_for_each_entry_safe(pos, tmp, head, list) { + list_del(&pos->list); + kfree(pos); + } +} + +static int +pidns_list_add(struct pid *pid, struct list_head *list_head, + struct pid_namespace *curr_ns) +{ + struct pidns_list *ent; + struct pid_namespace *ns; + + if (is_child_reaper(pid)) { + ent = kmalloc(sizeof(*ent), GFP_KERNEL); + if (!ent) + return -ENOMEM; + + ent->pid = pid; + ns = pid->numbers[pid->level].ns; + if (curr_ns) { + /* add pids who is the child of curr_ns */ + for (; ns != NULL; ns = ns->parent) + if (ns == curr_ns) + list_add_tail(&ent->list, list_head); + } else { + list_add_tail(&ent->list, list_head); + } + } + + return 0; +} + +static int +pidns_list_filter(void) +{ + struct pidns_list *pos, *pos_t; + struct pid_namespace *ns0, *ns1; + struct pid *pid0, *pid1; + int rc, flag = 0; + + /* screen pid with relationship + * in pidns_list, we may add pids like + * ns0 ns1 ns2 + * pid1->pid2->pid3 + * we should screen pid1, pid2 and keep pid3 + */ + list_for_each_entry(pos, &pidns_list, list) { + list_for_each_entry(pos_t, &pidns_list, list) { + flag = 0; + pid0 = pos->pid; + pid1 = pos_t->pid; + ns0 = pid0->numbers[pid0->level].ns; + ns1 = pid1->numbers[pid1->level].ns; + if (pos->pid->level < pos_t->pid->level) + for (; ns1 != NULL; ns1 = ns1->parent) + if (ns0 == ns1) { + flag = 1; + break; + } + if (flag == 1) + break; + } + + if (flag == 0) { + rc = pidns_list_add(pos->pid, &pidns_tree, NULL); + if (rc) + goto out; + } + } + + /* Now all usefull stuffs are in pidns_tree, free pidns_list*/ + free_pidns_list(&pidns_list); + + return 0; + +out: + free_pidns_list(&pidns_tree); + return rc; +} + +/* collect pids in pidns_list, + * then remove duplicated ones, + * add the rest to pidns_tree + */ +static int proc_pidns_list_refresh(struct pid_namespace *curr_ns) +{ + struct pid *pid; + struct task_struct *p; + int rc; + + /* collect pid in differet ns */ + for_each_process(p) { + pid = task_pid(p); + if (pid && (pid->level > 0)) { + rc = pidns_list_add(pid, &pidns_list, curr_ns); + if (rc) + goto out; + } + } + + /* screen duplicate pids from list pidns_list + * and form a new list pidns_tree + */ + rc = pidns_list_filter(); + if (rc) + goto out; + + return 0; + +out: + free_pidns_list(&pidns_list); + return rc; +} + +static int nslist_proc_show(struct seq_file *m, void *v) +{ + struct pidns_list *pos; + struct pid_namespace *ns, *curr_ns; + struct pid *pid; + char pid_buf[32]; + int i, curr_level; + int rc; + + curr_ns = task_active_pid_ns(current); + + mutex_lock(&pidns_list_lock); + rcu_read_lock(); + rc = proc_pidns_list_refresh(curr_ns); + if (rc) { + rcu_read_unlock(); + mutex_unlock(&pidns_list_lock); + return rc; + } + + /* print pid namespace hierarchy */ + list_for_each_entry(pos, &pidns_tree, list) { + pid = pos->pid; + curr_level = -1; + ns = pid->numbers[pid->level].ns; + /* Check whether a pid has relationship with current ns */ + for (; ns != NULL; ns = ns->parent) + if (ns == curr_ns) + curr_level = curr_ns->level; + + if (curr_level == -1) + continue; + + for (i = curr_level + 1; i <= pid->level; i++) { + ns = pid->numbers[i].ns; + /* show PID '1' in specific pid ns */ + snprintf(pid_buf, 32, "/proc/%u/ns/pid", + pid_vnr(find_pid_ns(1, ns))); + seq_printf(m, "%s ", pid_buf); + } + + seq_putc(m, '\n'); + } + + free_pidns_list(&pidns_tree); + rcu_read_unlock(); + mutex_unlock(&pidns_list_lock); + + return 0; +} + +static int nslist_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, nslist_proc_show, NULL); +} + +static const struct file_operations proc_nspid_nslist_fops = { + .open = nslist_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int __init pidns_hierarchy_init(void) +{ + proc_create(NS_HIERARCHY, S_IWUGO, + NULL, &proc_nspid_nslist_fops); + + return 0; +} +fs_initcall(pidns_hierarchy_init); 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