/** taskstats.c - Export per-task statistics to userland** Copyright (C) Shailabh Nagar, IBM Corp. 2006* (C) Balbir Singh, IBM Corp. 2006** This program is free software; you can redistribute it and/or modify* it under the terms of the GNU General Public License as published by* the Free Software Foundation; either version 2 of the License, or* (at your option) any later version.** This program is distributed in the hope that it will be useful,* but WITHOUT ANY WARRANTY; without even the implied warranty of* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the* GNU General Public License for more details.**/#include <linux/kernel.h>#include <linux/taskstats_kern.h>#include <linux/tsacct_kern.h>#include <linux/delayacct.h>#include <linux/cpumask.h>#include <linux/percpu.h>#include <linux/slab.h>#include <linux/cgroupstats.h>#include <linux/cgroup.h>#include <linux/fs.h>#include <linux/file.h>#include <linux/pid_namespace.h>#include <net/genetlink.h>#include <linux/atomic.h>/** Maximum length of a cpumask that can be specified in* the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute*/#define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)static DEFINE_PER_CPU(__u32, taskstats_seqnum);static int family_registered;struct kmem_cache *taskstats_cache;static struct genl_family family = {.id = GENL_ID_GENERATE,.name = TASKSTATS_GENL_NAME,.version = TASKSTATS_GENL_VERSION,.maxattr = TASKSTATS_CMD_ATTR_MAX,};static const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {[TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },[TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};static const struct nla_policy cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] = {[CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },};struct listener {struct list_head list;pid_t pid;char valid;};struct listener_list {struct rw_semaphore sem;struct list_head list;};static DEFINE_PER_CPU(struct listener_list, listener_array);enum actions {REGISTER,DEREGISTER,CPU_DONT_CARE};static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,size_t size){struct sk_buff *skb;void *reply;/** If new attributes are added, please revisit this allocation*/skb = genlmsg_new(size, GFP_KERNEL);if (!skb)return -ENOMEM;if (!info) {int seq = this_cpu_inc_return(taskstats_seqnum) - 1;reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);} elsereply = genlmsg_put_reply(skb, info, &family, 0, cmd);if (reply == NULL) {nlmsg_free(skb);return -EINVAL;}*skbp = skb;return 0;}/** Send taskstats data in @skb to listener with nl_pid @pid*/static int send_reply(struct sk_buff *skb, struct genl_info *info){struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));void *reply = genlmsg_data(genlhdr);genlmsg_end(skb, reply);return genlmsg_reply(skb, info);}/** Send taskstats data in @skb to listeners registered for @cpu's exit data*/static void send_cpu_listeners(struct sk_buff *skb,struct listener_list *listeners){struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));struct listener *s, *tmp;struct sk_buff *skb_next, *skb_cur = skb;void *reply = genlmsg_data(genlhdr);int rc, delcount = 0;genlmsg_end(skb, reply);rc = 0;down_read(&listeners->sem);list_for_each_entry(s, &listeners->list, list) {skb_next = NULL;if (!list_is_last(&s->list, &listeners->list)) {skb_next = skb_clone(skb_cur, GFP_KERNEL);if (!skb_next)break;}rc = genlmsg_unicast(&init_net, skb_cur, s->pid);if (rc == -ECONNREFUSED) {s->valid = 0;delcount++;}skb_cur = skb_next;}up_read(&listeners->sem);if (skb_cur)nlmsg_free(skb_cur);if (!delcount)return;/* Delete invalidated entries */down_write(&listeners->sem);list_for_each_entry_safe(s, tmp, &listeners->list, list) {if (!s->valid) {list_del(&s->list);kfree(s);}}up_write(&listeners->sem);}static void fill_stats(struct user_namespace *user_ns,struct pid_namespace *pid_ns,struct task_struct *tsk, struct taskstats *stats){memset(stats, 0, sizeof(*stats));/** Each accounting subsystem adds calls to its functions to* fill in relevant parts of struct taskstsats as follows** per-task-foo(stats, tsk);*/delayacct_add_tsk(stats, tsk);/* fill in basic acct fields */stats->version = TASKSTATS_VERSION;stats->nvcsw = tsk->nvcsw;stats->nivcsw = tsk->nivcsw;bacct_add_tsk(user_ns, pid_ns, stats, tsk);/* fill in extended acct fields */xacct_add_tsk(stats, tsk);}static int fill_stats_for_pid(pid_t pid, struct taskstats *stats){struct task_struct *tsk;rcu_read_lock();tsk = find_task_by_vpid(pid);if (tsk)get_task_struct(tsk);rcu_read_unlock();if (!tsk)return -ESRCH;fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);put_task_struct(tsk);return 0;}static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats){struct task_struct *tsk, *first;unsigned long flags;int rc = -ESRCH;/** Add additional stats from live tasks except zombie thread group* leaders who are already counted with the dead tasks*/rcu_read_lock();first = find_task_by_vpid(tgid);if (!first || !lock_task_sighand(first, &flags))goto out;if (first->signal->stats)memcpy(stats, first->signal->stats, sizeof(*stats));elsememset(stats, 0, sizeof(*stats));tsk = first;do {if (tsk->exit_state)continue;/** Accounting subsystem can call its functions here to* fill in relevant parts of struct taskstsats as follows** per-task-foo(stats, tsk);*/delayacct_add_tsk(stats, tsk);stats->nvcsw += tsk->nvcsw;stats->nivcsw += tsk->nivcsw;} while_each_thread(first, tsk);unlock_task_sighand(first, &flags);rc = 0;out:rcu_read_unlock();stats->version = TASKSTATS_VERSION;/** Accounting subsystems can also add calls here to modify* fields of taskstats.*/return rc;}static void fill_tgid_exit(struct task_struct *tsk){unsigned long flags;spin_lock_irqsave(&tsk->sighand->siglock, flags);if (!tsk->signal->stats)goto ret;/** Each accounting subsystem calls its functions here to* accumalate its per-task stats for tsk, into the per-tgid structure** per-task-foo(tsk->signal->stats, tsk);*/delayacct_add_tsk(tsk->signal->stats, tsk);ret:spin_unlock_irqrestore(&tsk->sighand->siglock, flags);return;}static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd){struct listener_list *listeners;struct listener *s, *tmp, *s2;unsigned int cpu;int ret = 0;if (!cpumask_subset(mask, cpu_possible_mask))return -EINVAL;if (current_user_ns() != &init_user_ns)return -EINVAL;if (task_active_pid_ns(current) != &init_pid_ns)return -EINVAL;if (isadd == REGISTER) {for_each_cpu(cpu, mask) {s = kmalloc_node(sizeof(struct listener),GFP_KERNEL, cpu_to_node(cpu));if (!s) {ret = -ENOMEM;goto cleanup;}s->pid = pid;s->valid = 1;listeners = &per_cpu(listener_array, cpu);down_write(&listeners->sem);list_for_each_entry(s2, &listeners->list, list) {if (s2->pid == pid && s2->valid)goto exists;}list_add(&s->list, &listeners->list);s = NULL;exists:up_write(&listeners->sem);kfree(s); /* nop if NULL */}return 0;}/* Deregister or cleanup */cleanup:for_each_cpu(cpu, mask) {listeners = &per_cpu(listener_array, cpu);down_write(&listeners->sem);list_for_each_entry_safe(s, tmp, &listeners->list, list) {if (s->pid == pid) {list_del(&s->list);kfree(s);break;}}up_write(&listeners->sem);}return ret;}static int parse(struct nlattr *na, struct cpumask *mask){char *data;int len;int ret;if (na == NULL)return 1;len = nla_len(na);if (len > TASKSTATS_CPUMASK_MAXLEN)return -E2BIG;if (len < 1)return -EINVAL;data = kmalloc(len, GFP_KERNEL);if (!data)return -ENOMEM;nla_strlcpy(data, na, len);ret = cpulist_parse(data, mask);kfree(data);return ret;}#if defined(CONFIG_64BIT) && !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)#define TASKSTATS_NEEDS_PADDING 1#endifstatic struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid){struct nlattr *na, *ret;int aggr;aggr = (type == TASKSTATS_TYPE_PID)? TASKSTATS_TYPE_AGGR_PID: TASKSTATS_TYPE_AGGR_TGID;/** The taskstats structure is internally aligned on 8 byte* boundaries but the layout of the aggregrate reply, with* two NLA headers and the pid (each 4 bytes), actually* force the entire structure to be unaligned. This causes* the kernel to issue unaligned access warnings on some* architectures like ia64. Unfortunately, some software out there* doesn't properly unroll the NLA packet and assumes that the start* of the taskstats structure will always be 20 bytes from the start* of the netlink payload. Aligning the start of the taskstats* structure breaks this software, which we don't want. So, for now* the alignment only happens on architectures that require it* and those users will have to update to fixed versions of those* packages. Space is reserved in the packet only when needed.* This ifdef should be removed in several years e.g. 2012 once* we can be confident that fixed versions are installed on most* systems. We add the padding before the aggregate since the* aggregate is already a defined type.*/#ifdef TASKSTATS_NEEDS_PADDINGif (nla_put(skb, TASKSTATS_TYPE_NULL, 0, NULL) < 0)goto err;#endifna = nla_nest_start(skb, aggr);if (!na)goto err;if (nla_put(skb, type, sizeof(pid), &pid) < 0) {nla_nest_cancel(skb, na);goto err;}ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats));if (!ret) {nla_nest_cancel(skb, na);goto err;}nla_nest_end(skb, na);return nla_data(ret);err:return NULL;}static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info){int rc = 0;struct sk_buff *rep_skb;struct cgroupstats *stats;struct nlattr *na;size_t size;u32 fd;struct fd f;na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];if (!na)return -EINVAL;fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);f = fdget(fd);if (!f.file)return 0;size = nla_total_size(sizeof(struct cgroupstats));rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,size);if (rc < 0)goto err;na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,sizeof(struct cgroupstats));if (na == NULL) {nlmsg_free(rep_skb);rc = -EMSGSIZE;goto err;}stats = nla_data(na);memset(stats, 0, sizeof(*stats));rc = cgroupstats_build(stats, f.file->f_path.dentry);if (rc < 0) {nlmsg_free(rep_skb);goto err;}rc = send_reply(rep_skb, info);err:fdput(f);return rc;}static int cmd_attr_register_cpumask(struct genl_info *info){cpumask_var_t mask;int rc;if (!alloc_cpumask_var(&mask, GFP_KERNEL))return -ENOMEM;rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);if (rc < 0)goto out;rc = add_del_listener(info->snd_portid, mask, REGISTER);out:free_cpumask_var(mask);return rc;}static int cmd_attr_deregister_cpumask(struct genl_info *info){cpumask_var_t mask;int rc;if (!alloc_cpumask_var(&mask, GFP_KERNEL))return -ENOMEM;rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);if (rc < 0)goto out;rc = add_del_listener(info->snd_portid, mask, DEREGISTER);out:free_cpumask_var(mask);return rc;}static size_t taskstats_packet_size(void){size_t size;size = nla_total_size(sizeof(u32)) +nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);#ifdef TASKSTATS_NEEDS_PADDINGsize += nla_total_size(0); /* Padding for alignment */#endifreturn size;}static int cmd_attr_pid(struct genl_info *info){struct taskstats *stats;struct sk_buff *rep_skb;size_t size;u32 pid;int rc;size = taskstats_packet_size();rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);if (rc < 0)return rc;rc = -EINVAL;pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);if (!stats)goto err;rc = fill_stats_for_pid(pid, stats);if (rc < 0)goto err;return send_reply(rep_skb, info);err:nlmsg_free(rep_skb);return rc;}static int cmd_attr_tgid(struct genl_info *info){struct taskstats *stats;struct sk_buff *rep_skb;size_t size;u32 tgid;int rc;size = taskstats_packet_size();rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);if (rc < 0)return rc;rc = -EINVAL;tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);if (!stats)goto err;rc = fill_stats_for_tgid(tgid, stats);if (rc < 0)goto err;return send_reply(rep_skb, info);err:nlmsg_free(rep_skb);return rc;}static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info){if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])return cmd_attr_register_cpumask(info);else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])return cmd_attr_deregister_cpumask(info);else if (info->attrs[TASKSTATS_CMD_ATTR_PID])return cmd_attr_pid(info);else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])return cmd_attr_tgid(info);elsereturn -EINVAL;}static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk){struct signal_struct *sig = tsk->signal;struct taskstats *stats;if (sig->stats || thread_group_empty(tsk))goto ret;/* No problem if kmem_cache_zalloc() fails */stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);spin_lock_irq(&tsk->sighand->siglock);if (!sig->stats) {sig->stats = stats;stats = NULL;}spin_unlock_irq(&tsk->sighand->siglock);if (stats)kmem_cache_free(taskstats_cache, stats);ret:return sig->stats;}/* Send pid data out on exit */void taskstats_exit(struct task_struct *tsk, int group_dead){int rc;struct listener_list *listeners;struct taskstats *stats;struct sk_buff *rep_skb;size_t size;int is_thread_group;if (!family_registered)return;/** Size includes space for nested attributes*/size = taskstats_packet_size();is_thread_group = !!taskstats_tgid_alloc(tsk);if (is_thread_group) {/* PID + STATS + TGID + STATS */size = 2 * size;/* fill the tsk->signal->stats structure */fill_tgid_exit(tsk);}listeners = raw_cpu_ptr(&listener_array);if (list_empty(&listeners->list))return;rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);if (rc < 0)return;stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,task_pid_nr_ns(tsk, &init_pid_ns));if (!stats)goto err;fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);/** Doesn't matter if tsk is the leader or the last group member leaving*/if (!is_thread_group || !group_dead)goto send;stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,task_tgid_nr_ns(tsk, &init_pid_ns));if (!stats)goto err;memcpy(stats, tsk->signal->stats, sizeof(*stats));send:send_cpu_listeners(rep_skb, listeners);return;err:nlmsg_free(rep_skb);}static const struct genl_ops taskstats_ops[] = {{.cmd = TASKSTATS_CMD_GET,.doit = taskstats_user_cmd,.policy = taskstats_cmd_get_policy,.flags = GENL_ADMIN_PERM,},{.cmd = CGROUPSTATS_CMD_GET,.doit = cgroupstats_user_cmd,.policy = cgroupstats_cmd_get_policy,},};/* Needed early in initialization */void __init taskstats_init_early(void){unsigned int i;taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);for_each_possible_cpu(i) {INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));init_rwsem(&(per_cpu(listener_array, i).sem));}}static int __init taskstats_init(void){int rc;rc = genl_register_family_with_ops(&family, taskstats_ops);if (rc)return rc;family_registered = 1;pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);return 0;}/** late initcall ensures initialization of statistics collection* mechanisms precedes initialization of the taskstats interface*/late_initcall(taskstats_init);
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