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1/*
2 * taskstats.c - Export per-task statistics to userland
3 *
4 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
5 * (C) Balbir Singh, IBM Corp. 2006
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 */
18
19#include <linux/kernel.h>
20#include <linux/taskstats_kern.h>
21#include <linux/tsacct_kern.h>
22#include <linux/delayacct.h>
23#include <linux/cpumask.h>
24#include <linux/percpu.h>
25#include <linux/slab.h>
26#include <linux/cgroupstats.h>
27#include <linux/cgroup.h>
28#include <linux/fs.h>
29#include <linux/file.h>
30#include <linux/pid_namespace.h>
31#include <net/genetlink.h>
32#include <linux/atomic.h>
33
34/*
35 * Maximum length of a cpumask that can be specified in
36 * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
37 */
38#define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
39
40static DEFINE_PER_CPU(__u32, taskstats_seqnum);
41static int family_registered;
42struct kmem_cache *taskstats_cache;
43
44static struct genl_family family = {
45 .id = GENL_ID_GENERATE,
46 .name = TASKSTATS_GENL_NAME,
47 .version = TASKSTATS_GENL_VERSION,
48 .maxattr = TASKSTATS_CMD_ATTR_MAX,
49};
50
51static const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {
52 [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
53 [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
54 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
55 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
56
57/*
58 * We have to use TASKSTATS_CMD_ATTR_MAX here, it is the maxattr in the family.
59 * Make sure they are always aligned.
60 */
61static const struct nla_policy cgroupstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {
62 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
63};
64
65struct listener {
66 struct list_head list;
67 pid_t pid;
68 char valid;
69};
70
71struct listener_list {
72 struct rw_semaphore sem;
73 struct list_head list;
74};
75static DEFINE_PER_CPU(struct listener_list, listener_array);
76
77enum actions {
78 REGISTER,
79 DEREGISTER,
80 CPU_DONT_CARE
81};
82
83static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
84 size_t size)
85{
86 struct sk_buff *skb;
87 void *reply;
88
89 /*
90 * If new attributes are added, please revisit this allocation
91 */
92 skb = genlmsg_new(size, GFP_KERNEL);
93 if (!skb)
94 return -ENOMEM;
95
96 if (!info) {
97 int seq = this_cpu_inc_return(taskstats_seqnum) - 1;
98
99 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
100 } else
101 reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
102 if (reply == NULL) {
103 nlmsg_free(skb);
104 return -EINVAL;
105 }
106
107 *skbp = skb;
108 return 0;
109}
110
111/*
112 * Send taskstats data in @skb to listener with nl_pid @pid
113 */
114static int send_reply(struct sk_buff *skb, struct genl_info *info)
115{
116 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
117 void *reply = genlmsg_data(genlhdr);
118
119 genlmsg_end(skb, reply);
120
121 return genlmsg_reply(skb, info);
122}
123
124/*
125 * Send taskstats data in @skb to listeners registered for @cpu's exit data
126 */
127static void send_cpu_listeners(struct sk_buff *skb,
128 struct listener_list *listeners)
129{
130 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
131 struct listener *s, *tmp;
132 struct sk_buff *skb_next, *skb_cur = skb;
133 void *reply = genlmsg_data(genlhdr);
134 int rc, delcount = 0;
135
136 genlmsg_end(skb, reply);
137
138 rc = 0;
139 down_read(&listeners->sem);
140 list_for_each_entry(s, &listeners->list, list) {
141 skb_next = NULL;
142 if (!list_is_last(&s->list, &listeners->list)) {
143 skb_next = skb_clone(skb_cur, GFP_KERNEL);
144 if (!skb_next)
145 break;
146 }
147 rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
148 if (rc == -ECONNREFUSED) {
149 s->valid = 0;
150 delcount++;
151 }
152 skb_cur = skb_next;
153 }
154 up_read(&listeners->sem);
155
156 if (skb_cur)
157 nlmsg_free(skb_cur);
158
159 if (!delcount)
160 return;
161
162 /* Delete invalidated entries */
163 down_write(&listeners->sem);
164 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
165 if (!s->valid) {
166 list_del(&s->list);
167 kfree(s);
168 }
169 }
170 up_write(&listeners->sem);
171}
172
173static void fill_stats(struct user_namespace *user_ns,
174 struct pid_namespace *pid_ns,
175 struct task_struct *tsk, struct taskstats *stats)
176{
177 memset(stats, 0, sizeof(*stats));
178 /*
179 * Each accounting subsystem adds calls to its functions to
180 * fill in relevant parts of struct taskstsats as follows
181 *
182 * per-task-foo(stats, tsk);
183 */
184
185 delayacct_add_tsk(stats, tsk);
186
187 /* fill in basic acct fields */
188 stats->version = TASKSTATS_VERSION;
189 stats->nvcsw = tsk->nvcsw;
190 stats->nivcsw = tsk->nivcsw;
191 bacct_add_tsk(user_ns, pid_ns, stats, tsk);
192
193 /* fill in extended acct fields */
194 xacct_add_tsk(stats, tsk);
195}
196
197static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
198{
199 struct task_struct *tsk;
200
201 rcu_read_lock();
202 tsk = find_task_by_vpid(pid);
203 if (tsk)
204 get_task_struct(tsk);
205 rcu_read_unlock();
206 if (!tsk)
207 return -ESRCH;
208 fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);
209 put_task_struct(tsk);
210 return 0;
211}
212
213static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats)
214{
215 struct task_struct *tsk, *first;
216 unsigned long flags;
217 int rc = -ESRCH;
218
219 /*
220 * Add additional stats from live tasks except zombie thread group
221 * leaders who are already counted with the dead tasks
222 */
223 rcu_read_lock();
224 first = find_task_by_vpid(tgid);
225
226 if (!first || !lock_task_sighand(first, &flags))
227 goto out;
228
229 if (first->signal->stats)
230 memcpy(stats, first->signal->stats, sizeof(*stats));
231 else
232 memset(stats, 0, sizeof(*stats));
233
234 tsk = first;
235 do {
236 if (tsk->exit_state)
237 continue;
238 /*
239 * Accounting subsystem can call its functions here to
240 * fill in relevant parts of struct taskstsats as follows
241 *
242 * per-task-foo(stats, tsk);
243 */
244 delayacct_add_tsk(stats, tsk);
245
246 stats->nvcsw += tsk->nvcsw;
247 stats->nivcsw += tsk->nivcsw;
248 } while_each_thread(first, tsk);
249
250 unlock_task_sighand(first, &flags);
251 rc = 0;
252out:
253 rcu_read_unlock();
254
255 stats->version = TASKSTATS_VERSION;
256 /*
257 * Accounting subsystems can also add calls here to modify
258 * fields of taskstats.
259 */
260 return rc;
261}
262
263static void fill_tgid_exit(struct task_struct *tsk)
264{
265 unsigned long flags;
266
267 spin_lock_irqsave(&tsk->sighand->siglock, flags);
268 if (!tsk->signal->stats)
269 goto ret;
270
271 /*
272 * Each accounting subsystem calls its functions here to
273 * accumalate its per-task stats for tsk, into the per-tgid structure
274 *
275 * per-task-foo(tsk->signal->stats, tsk);
276 */
277 delayacct_add_tsk(tsk->signal->stats, tsk);
278ret:
279 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
280 return;
281}
282
283static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
284{
285 struct listener_list *listeners;
286 struct listener *s, *tmp, *s2;
287 unsigned int cpu;
288 int ret = 0;
289
290 if (!cpumask_subset(mask, cpu_possible_mask))
291 return -EINVAL;
292
293 if (current_user_ns() != &init_user_ns)
294 return -EINVAL;
295
296 if (task_active_pid_ns(current) != &init_pid_ns)
297 return -EINVAL;
298
299 if (isadd == REGISTER) {
300 for_each_cpu(cpu, mask) {
301 s = kmalloc_node(sizeof(struct listener),
302 GFP_KERNEL, cpu_to_node(cpu));
303 if (!s) {
304 ret = -ENOMEM;
305 goto cleanup;
306 }
307 s->pid = pid;
308 s->valid = 1;
309
310 listeners = &per_cpu(listener_array, cpu);
311 down_write(&listeners->sem);
312 list_for_each_entry(s2, &listeners->list, list) {
313 if (s2->pid == pid && s2->valid)
314 goto exists;
315 }
316 list_add(&s->list, &listeners->list);
317 s = NULL;
318exists:
319 up_write(&listeners->sem);
320 kfree(s); /* nop if NULL */
321 }
322 return 0;
323 }
324
325 /* Deregister or cleanup */
326cleanup:
327 for_each_cpu(cpu, mask) {
328 listeners = &per_cpu(listener_array, cpu);
329 down_write(&listeners->sem);
330 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
331 if (s->pid == pid) {
332 list_del(&s->list);
333 kfree(s);
334 break;
335 }
336 }
337 up_write(&listeners->sem);
338 }
339 return ret;
340}
341
342static int parse(struct nlattr *na, struct cpumask *mask)
343{
344 char *data;
345 int len;
346 int ret;
347
348 if (na == NULL)
349 return 1;
350 len = nla_len(na);
351 if (len > TASKSTATS_CPUMASK_MAXLEN)
352 return -E2BIG;
353 if (len < 1)
354 return -EINVAL;
355 data = kmalloc(len, GFP_KERNEL);
356 if (!data)
357 return -ENOMEM;
358 nla_strlcpy(data, na, len);
359 ret = cpulist_parse(data, mask);
360 kfree(data);
361 return ret;
362}
363
364static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
365{
366 struct nlattr *na, *ret;
367 int aggr;
368
369 aggr = (type == TASKSTATS_TYPE_PID)
370 ? TASKSTATS_TYPE_AGGR_PID
371 : TASKSTATS_TYPE_AGGR_TGID;
372
373 na = nla_nest_start(skb, aggr);
374 if (!na)
375 goto err;
376
377 if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
378 nla_nest_cancel(skb, na);
379 goto err;
380 }
381 ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
382 sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
383 if (!ret) {
384 nla_nest_cancel(skb, na);
385 goto err;
386 }
387 nla_nest_end(skb, na);
388
389 return nla_data(ret);
390err:
391 return NULL;
392}
393
394static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
395{
396 int rc = 0;
397 struct sk_buff *rep_skb;
398 struct cgroupstats *stats;
399 struct nlattr *na;
400 size_t size;
401 u32 fd;
402 struct fd f;
403
404 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
405 if (!na)
406 return -EINVAL;
407
408 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
409 f = fdget(fd);
410 if (!f.file)
411 return 0;
412
413 size = nla_total_size(sizeof(struct cgroupstats));
414
415 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
416 size);
417 if (rc < 0)
418 goto err;
419
420 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
421 sizeof(struct cgroupstats));
422 if (na == NULL) {
423 nlmsg_free(rep_skb);
424 rc = -EMSGSIZE;
425 goto err;
426 }
427
428 stats = nla_data(na);
429 memset(stats, 0, sizeof(*stats));
430
431 rc = cgroupstats_build(stats, f.file->f_path.dentry);
432 if (rc < 0) {
433 nlmsg_free(rep_skb);
434 goto err;
435 }
436
437 rc = send_reply(rep_skb, info);
438
439err:
440 fdput(f);
441 return rc;
442}
443
444static int cmd_attr_register_cpumask(struct genl_info *info)
445{
446 cpumask_var_t mask;
447 int rc;
448
449 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
450 return -ENOMEM;
451 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
452 if (rc < 0)
453 goto out;
454 rc = add_del_listener(info->snd_portid, mask, REGISTER);
455out:
456 free_cpumask_var(mask);
457 return rc;
458}
459
460static int cmd_attr_deregister_cpumask(struct genl_info *info)
461{
462 cpumask_var_t mask;
463 int rc;
464
465 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
466 return -ENOMEM;
467 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
468 if (rc < 0)
469 goto out;
470 rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
471out:
472 free_cpumask_var(mask);
473 return rc;
474}
475
476static size_t taskstats_packet_size(void)
477{
478 size_t size;
479
480 size = nla_total_size(sizeof(u32)) +
481 nla_total_size_64bit(sizeof(struct taskstats)) +
482 nla_total_size(0);
483
484 return size;
485}
486
487static int cmd_attr_pid(struct genl_info *info)
488{
489 struct taskstats *stats;
490 struct sk_buff *rep_skb;
491 size_t size;
492 u32 pid;
493 int rc;
494
495 size = taskstats_packet_size();
496
497 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
498 if (rc < 0)
499 return rc;
500
501 rc = -EINVAL;
502 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
503 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
504 if (!stats)
505 goto err;
506
507 rc = fill_stats_for_pid(pid, stats);
508 if (rc < 0)
509 goto err;
510 return send_reply(rep_skb, info);
511err:
512 nlmsg_free(rep_skb);
513 return rc;
514}
515
516static int cmd_attr_tgid(struct genl_info *info)
517{
518 struct taskstats *stats;
519 struct sk_buff *rep_skb;
520 size_t size;
521 u32 tgid;
522 int rc;
523
524 size = taskstats_packet_size();
525
526 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
527 if (rc < 0)
528 return rc;
529
530 rc = -EINVAL;
531 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
532 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
533 if (!stats)
534 goto err;
535
536 rc = fill_stats_for_tgid(tgid, stats);
537 if (rc < 0)
538 goto err;
539 return send_reply(rep_skb, info);
540err:
541 nlmsg_free(rep_skb);
542 return rc;
543}
544
545static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
546{
547 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
548 return cmd_attr_register_cpumask(info);
549 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
550 return cmd_attr_deregister_cpumask(info);
551 else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
552 return cmd_attr_pid(info);
553 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
554 return cmd_attr_tgid(info);
555 else
556 return -EINVAL;
557}
558
559static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
560{
561 struct signal_struct *sig = tsk->signal;
562 struct taskstats *stats;
563
564 if (sig->stats || thread_group_empty(tsk))
565 goto ret;
566
567 /* No problem if kmem_cache_zalloc() fails */
568 stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
569
570 spin_lock_irq(&tsk->sighand->siglock);
571 if (!sig->stats) {
572 sig->stats = stats;
573 stats = NULL;
574 }
575 spin_unlock_irq(&tsk->sighand->siglock);
576
577 if (stats)
578 kmem_cache_free(taskstats_cache, stats);
579ret:
580 return sig->stats;
581}
582
583/* Send pid data out on exit */
584void taskstats_exit(struct task_struct *tsk, int group_dead)
585{
586 int rc;
587 struct listener_list *listeners;
588 struct taskstats *stats;
589 struct sk_buff *rep_skb;
590 size_t size;
591 int is_thread_group;
592
593 if (!family_registered)
594 return;
595
596 /*
597 * Size includes space for nested attributes
598 */
599 size = taskstats_packet_size();
600
601 is_thread_group = !!taskstats_tgid_alloc(tsk);
602 if (is_thread_group) {
603 /* PID + STATS + TGID + STATS */
604 size = 2 * size;
605 /* fill the tsk->signal->stats structure */
606 fill_tgid_exit(tsk);
607 }
608
609 listeners = raw_cpu_ptr(&listener_array);
610 if (list_empty(&listeners->list))
611 return;
612
613 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
614 if (rc < 0)
615 return;
616
617 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
618 task_pid_nr_ns(tsk, &init_pid_ns));
619 if (!stats)
620 goto err;
621
622 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
623
624 /*
625 * Doesn't matter if tsk is the leader or the last group member leaving
626 */
627 if (!is_thread_group || !group_dead)
628 goto send;
629
630 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
631 task_tgid_nr_ns(tsk, &init_pid_ns));
632 if (!stats)
633 goto err;
634
635 memcpy(stats, tsk->signal->stats, sizeof(*stats));
636
637send:
638 send_cpu_listeners(rep_skb, listeners);
639 return;
640err:
641 nlmsg_free(rep_skb);
642}
643
644static const struct genl_ops taskstats_ops[] = {
645 {
646 .cmd = TASKSTATS_CMD_GET,
647 .doit = taskstats_user_cmd,
648 .policy = taskstats_cmd_get_policy,
649 .flags = GENL_ADMIN_PERM,
650 },
651 {
652 .cmd = CGROUPSTATS_CMD_GET,
653 .doit = cgroupstats_user_cmd,
654 .policy = cgroupstats_cmd_get_policy,
655 },
656};
657
658/* Needed early in initialization */
659void __init taskstats_init_early(void)
660{
661 unsigned int i;
662
663 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
664 for_each_possible_cpu(i) {
665 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
666 init_rwsem(&(per_cpu(listener_array, i).sem));
667 }
668}
669
670static int __init taskstats_init(void)
671{
672 int rc;
673
674 rc = genl_register_family_with_ops(&family, taskstats_ops);
675 if (rc)
676 return rc;
677
678 family_registered = 1;
679 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
680 return 0;
681}
682
683/*
684 * late initcall ensures initialization of statistics collection
685 * mechanisms precedes initialization of the taskstats interface
686 */
687late_initcall(taskstats_init);