Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754836AbbGFIzb (ORCPT ); Mon, 6 Jul 2015 04:55:31 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:24315 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754320AbbGFIuz (ORCPT ); Mon, 6 Jul 2015 04:50:55 -0400 From: Andrey Vagin To: linux-kernel@vger.kernel.org Cc: linux-api@vger.kernel.org, Andrey Vagin , Oleg Nesterov , Andrew Morton , Cyrill Gorcunov , Pavel Emelyanov , Roger Luethi , Arnd Bergmann , Arnaldo Carvalho de Melo , David Ahern , Andy Lutomirski , Pavel Odintsov Subject: [PATCH 10/24] task_diag: add ability to dump children (v2) Date: Mon, 6 Jul 2015 11:47:11 +0300 Message-Id: <1436172445-6979-11-git-send-email-avagin@openvz.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1436172445-6979-1-git-send-email-avagin@openvz.org> References: <1436172445-6979-1-git-send-email-avagin@openvz.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4498 Lines: 183 Now we can dump all task or children of a specified task. It's an example how this interface can be expanded for different use-cases. v2: Fixes from David Ahern Add missing break in iter_stop Fix 8-byte alignment issues Cc: David Ahern Signed-off-by: Andrey Vagin --- include/uapi/linux/task_diag.h | 1 + kernel/taskdiag.c | 117 +++++++++++++++++++++++++++++++++++------ 2 files changed, 102 insertions(+), 16 deletions(-) diff --git a/include/uapi/linux/task_diag.h b/include/uapi/linux/task_diag.h index 0e659d6..af192db 100644 --- a/include/uapi/linux/task_diag.h +++ b/include/uapi/linux/task_diag.h @@ -63,6 +63,7 @@ struct task_diag_creds { }; #define TASK_DIAG_DUMP_ALL 0 +#define TASK_DIAG_DUMP_CHILDREN 1 struct task_diag_pid { __u64 show_flags; diff --git a/kernel/taskdiag.c b/kernel/taskdiag.c index 5123e12..6dd3361 100644 --- a/kernel/taskdiag.c +++ b/kernel/taskdiag.c @@ -184,42 +184,127 @@ err: return err; } +struct task_iter { + struct task_diag_pid req; + struct pid_namespace *ns; + struct netlink_callback *cb; + struct task_struct *parent; + + union { + struct tgid_iter tgid; + struct { + unsigned int pos; + struct task_struct *task; + }; + }; +}; + +static void iter_stop(struct task_iter *iter) +{ + struct task_struct *task; + + if (iter->parent) + put_task_struct(iter->parent); + + switch (iter->req.dump_strategy) { + case TASK_DIAG_DUMP_ALL: + task = iter->tgid.task; + break; + default: + task = iter->task; + } + if (task) + put_task_struct(task); +} + +static struct task_struct *iter_start(struct task_iter *iter) +{ + if (iter->req.pid > 0) { + rcu_read_lock(); + iter->parent = find_task_by_pid_ns(iter->req.pid, iter->ns); + if (iter->parent) + get_task_struct(iter->parent); + rcu_read_unlock(); + } + + switch (iter->req.dump_strategy) { + case TASK_DIAG_DUMP_CHILDREN: + + if (iter->parent == NULL) + return ERR_PTR(-ESRCH); + + iter->pos = iter->cb->args[0]; + iter->task = task_next_child(iter->parent, NULL, iter->pos); + return iter->task; + + case TASK_DIAG_DUMP_ALL: + iter->tgid.tgid = iter->cb->args[0]; + iter->tgid.task = NULL; + iter->tgid = next_tgid(iter->ns, iter->tgid); + return iter->tgid.task; + } + + return ERR_PTR(-EINVAL); +} + +static struct task_struct *iter_next(struct task_iter *iter) +{ + switch (iter->req.dump_strategy) { + case TASK_DIAG_DUMP_CHILDREN: + iter->pos++; + iter->task = task_next_child(iter->parent, iter->task, iter->pos); + iter->cb->args[0] = iter->pos; + return iter->task; + + case TASK_DIAG_DUMP_ALL: + iter->tgid.tgid += 1; + iter->tgid = next_tgid(iter->ns, iter->tgid); + iter->cb->args[0] = iter->tgid.tgid; + return iter->tgid.task; + } + + return NULL; +} + int taskdiag_dumpit(struct sk_buff *skb, struct netlink_callback *cb) { struct pid_namespace *ns = task_active_pid_ns(current); - struct tgid_iter iter; + struct task_iter iter; struct nlattr *na; - struct task_diag_pid req; + struct task_struct *task; int rc; - if (nlmsg_len(cb->nlh) < GENL_HDRLEN + sizeof(req)) + if (nlmsg_len(cb->nlh) < GENL_HDRLEN + sizeof(iter.req)) return -EINVAL; na = nlmsg_data(cb->nlh) + GENL_HDRLEN; if (na->nla_type < 0) return -EINVAL; - memcpy(&req, nla_data(na), sizeof(req)); + memcpy(&iter.req, nla_data(na), sizeof(iter.req)); - iter.tgid = cb->args[0]; - iter.task = NULL; - for (iter = next_tgid(ns, iter); - iter.task; - iter.tgid += 1, iter = next_tgid(ns, iter)) { - if (!ptrace_may_access(iter.task, PTRACE_MODE_READ)) - continue; + iter.ns = ns; + iter.cb = cb; + iter.parent = NULL; - rc = task_diag_fill(iter.task, skb, req.show_flags, + task = iter_start(&iter); + if (IS_ERR(task)) + return PTR_ERR(task); + + for (; task; task = iter_next(&iter)) { + if (!ptrace_may_access(task, PTRACE_MODE_READ)) + continue; + rc = task_diag_fill(task, skb, iter.req.show_flags, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, cb); if (rc < 0) { - put_task_struct(iter.task); - if (rc != -EMSGSIZE) + if (rc != -EMSGSIZE) { + iter_stop(&iter); return rc; + } break; } } - - cb->args[0] = iter.tgid; + iter_stop(&iter); return skb->len; } -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/