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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 #include <linux/sched/cputime.h>
34
35 /*
36 * Maximum length of a cpumask that can be specified in
37 * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
38 */
39 #define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
40
41 static DEFINE_PER_CPU(__u32, taskstats_seqnum);
42 static int family_registered;
43 struct kmem_cache *taskstats_cache;
44
45 static struct genl_family family;
46
47 static const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {
48 [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
49 [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
50 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
51 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
52
53 /*
54 * We have to use TASKSTATS_CMD_ATTR_MAX here, it is the maxattr in the family.
55 * Make sure they are always aligned.
56 */
57 static const struct nla_policy cgroupstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {
58 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
59 };
60
61 struct listener {
62 struct list_head list;
63 pid_t pid;
64 char valid;
65 };
66
67 struct listener_list {
68 struct rw_semaphore sem;
69 struct list_head list;
70 };
71 static DEFINE_PER_CPU(struct listener_list, listener_array);
72
73 enum actions {
74 REGISTER,
75 DEREGISTER,
76 CPU_DONT_CARE
77 };
78
79 static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
80 size_t size)
81 {
82 struct sk_buff *skb;
83 void *reply;
84
85 /*
86 * If new attributes are added, please revisit this allocation
87 */
88 skb = genlmsg_new(size, GFP_KERNEL);
89 if (!skb)
90 return -ENOMEM;
91
92 if (!info) {
93 int seq = this_cpu_inc_return(taskstats_seqnum) - 1;
94
95 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
96 } else
97 reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
98 if (reply == NULL) {
99 nlmsg_free(skb);
100 return -EINVAL;
101 }
102
103 *skbp = skb;
104 return 0;
105 }
106
107 /*
108 * Send taskstats data in @skb to listener with nl_pid @pid
109 */
110 static int send_reply(struct sk_buff *skb, struct genl_info *info)
111 {
112 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
113 void *reply = genlmsg_data(genlhdr);
114
115 genlmsg_end(skb, reply);
116
117 return genlmsg_reply(skb, info);
118 }
119
120 /*
121 * Send taskstats data in @skb to listeners registered for @cpu's exit data
122 */
123 static void send_cpu_listeners(struct sk_buff *skb,
124 struct listener_list *listeners)
125 {
126 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
127 struct listener *s, *tmp;
128 struct sk_buff *skb_next, *skb_cur = skb;
129 void *reply = genlmsg_data(genlhdr);
130 int rc, delcount = 0;
131
132 genlmsg_end(skb, reply);
133
134 rc = 0;
135 down_read(&listeners->sem);
136 list_for_each_entry(s, &listeners->list, list) {
137 skb_next = NULL;
138 if (!list_is_last(&s->list, &listeners->list)) {
139 skb_next = skb_clone(skb_cur, GFP_KERNEL);
140 if (!skb_next)
141 break;
142 }
143 rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
144 if (rc == -ECONNREFUSED) {
145 s->valid = 0;
146 delcount++;
147 }
148 skb_cur = skb_next;
149 }
150 up_read(&listeners->sem);
151
152 if (skb_cur)
153 nlmsg_free(skb_cur);
154
155 if (!delcount)
156 return;
157
158 /* Delete invalidated entries */
159 down_write(&listeners->sem);
160 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
161 if (!s->valid) {
162 list_del(&s->list);
163 kfree(s);
164 }
165 }
166 up_write(&listeners->sem);
167 }
168
169 static void fill_stats(struct user_namespace *user_ns,
170 struct pid_namespace *pid_ns,
171 struct task_struct *tsk, struct taskstats *stats)
172 {
173 memset(stats, 0, sizeof(*stats));
174 /*
175 * Each accounting subsystem adds calls to its functions to
176 * fill in relevant parts of struct taskstsats as follows
177 *
178 * per-task-foo(stats, tsk);
179 */
180
181 delayacct_add_tsk(stats, tsk);
182
183 /* fill in basic acct fields */
184 stats->version = TASKSTATS_VERSION;
185 stats->nvcsw = tsk->nvcsw;
186 stats->nivcsw = tsk->nivcsw;
187 bacct_add_tsk(user_ns, pid_ns, stats, tsk);
188
189 /* fill in extended acct fields */
190 xacct_add_tsk(stats, tsk);
191 }
192
193 static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
194 {
195 struct task_struct *tsk;
196
197 rcu_read_lock();
198 tsk = find_task_by_vpid(pid);
199 if (tsk)
200 get_task_struct(tsk);
201 rcu_read_unlock();
202 if (!tsk)
203 return -ESRCH;
204 fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);
205 put_task_struct(tsk);
206 return 0;
207 }
208
209 static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats)
210 {
211 struct task_struct *tsk, *first;
212 unsigned long flags;
213 int rc = -ESRCH;
214 u64 delta, utime, stime;
215 u64 start_time;
216
217 /*
218 * Add additional stats from live tasks except zombie thread group
219 * leaders who are already counted with the dead tasks
220 */
221 rcu_read_lock();
222 first = find_task_by_vpid(tgid);
223
224 if (!first || !lock_task_sighand(first, &flags))
225 goto out;
226
227 if (first->signal->stats)
228 memcpy(stats, first->signal->stats, sizeof(*stats));
229 else
230 memset(stats, 0, sizeof(*stats));
231
232 tsk = first;
233 start_time = ktime_get_ns();
234 do {
235 if (tsk->exit_state)
236 continue;
237 /*
238 * Accounting subsystem can call its functions here to
239 * fill in relevant parts of struct taskstsats as follows
240 *
241 * per-task-foo(stats, tsk);
242 */
243 delayacct_add_tsk(stats, tsk);
244
245 /* calculate task elapsed time in nsec */
246 delta = start_time - tsk->start_time;
247 /* Convert to micro seconds */
248 do_div(delta, NSEC_PER_USEC);
249 stats->ac_etime += delta;
250
251 task_cputime(tsk, &utime, &stime);
252 stats->ac_utime += div_u64(utime, NSEC_PER_USEC);
253 stats->ac_stime += div_u64(stime, NSEC_PER_USEC);
254
255 stats->nvcsw += tsk->nvcsw;
256 stats->nivcsw += tsk->nivcsw;
257 } while_each_thread(first, tsk);
258
259 unlock_task_sighand(first, &flags);
260 rc = 0;
261 out:
262 rcu_read_unlock();
263
264 stats->version = TASKSTATS_VERSION;
265 /*
266 * Accounting subsystems can also add calls here to modify
267 * fields of taskstats.
268 */
269 return rc;
270 }
271
272 static void fill_tgid_exit(struct task_struct *tsk)
273 {
274 unsigned long flags;
275
276 spin_lock_irqsave(&tsk->sighand->siglock, flags);
277 if (!tsk->signal->stats)
278 goto ret;
279
280 /*
281 * Each accounting subsystem calls its functions here to
282 * accumalate its per-task stats for tsk, into the per-tgid structure
283 *
284 * per-task-foo(tsk->signal->stats, tsk);
285 */
286 delayacct_add_tsk(tsk->signal->stats, tsk);
287 ret:
288 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
289 return;
290 }
291
292 static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
293 {
294 struct listener_list *listeners;
295 struct listener *s, *tmp, *s2;
296 unsigned int cpu;
297 int ret = 0;
298
299 if (!cpumask_subset(mask, cpu_possible_mask))
300 return -EINVAL;
301
302 if (current_user_ns() != &init_user_ns)
303 return -EINVAL;
304
305 if (task_active_pid_ns(current) != &init_pid_ns)
306 return -EINVAL;
307
308 if (isadd == REGISTER) {
309 for_each_cpu(cpu, mask) {
310 s = kmalloc_node(sizeof(struct listener),
311 GFP_KERNEL, cpu_to_node(cpu));
312 if (!s) {
313 ret = -ENOMEM;
314 goto cleanup;
315 }
316 s->pid = pid;
317 s->valid = 1;
318
319 listeners = &per_cpu(listener_array, cpu);
320 down_write(&listeners->sem);
321 list_for_each_entry(s2, &listeners->list, list) {
322 if (s2->pid == pid && s2->valid)
323 goto exists;
324 }
325 list_add(&s->list, &listeners->list);
326 s = NULL;
327 exists:
328 up_write(&listeners->sem);
329 kfree(s); /* nop if NULL */
330 }
331 return 0;
332 }
333
334 /* Deregister or cleanup */
335 cleanup:
336 for_each_cpu(cpu, mask) {
337 listeners = &per_cpu(listener_array, cpu);
338 down_write(&listeners->sem);
339 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
340 if (s->pid == pid) {
341 list_del(&s->list);
342 kfree(s);
343 break;
344 }
345 }
346 up_write(&listeners->sem);
347 }
348 return ret;
349 }
350
351 static int parse(struct nlattr *na, struct cpumask *mask)
352 {
353 char *data;
354 int len;
355 int ret;
356
357 if (na == NULL)
358 return 1;
359 len = nla_len(na);
360 if (len > TASKSTATS_CPUMASK_MAXLEN)
361 return -E2BIG;
362 if (len < 1)
363 return -EINVAL;
364 data = kmalloc(len, GFP_KERNEL);
365 if (!data)
366 return -ENOMEM;
367 nla_strlcpy(data, na, len);
368 ret = cpulist_parse(data, mask);
369 kfree(data);
370 return ret;
371 }
372
373 static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
374 {
375 struct nlattr *na, *ret;
376 int aggr;
377
378 aggr = (type == TASKSTATS_TYPE_PID)
379 ? TASKSTATS_TYPE_AGGR_PID
380 : TASKSTATS_TYPE_AGGR_TGID;
381
382 na = nla_nest_start(skb, aggr);
383 if (!na)
384 goto err;
385
386 if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
387 nla_nest_cancel(skb, na);
388 goto err;
389 }
390 ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
391 sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
392 if (!ret) {
393 nla_nest_cancel(skb, na);
394 goto err;
395 }
396 nla_nest_end(skb, na);
397
398 return nla_data(ret);
399 err:
400 return NULL;
401 }
402
403 static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
404 {
405 int rc = 0;
406 struct sk_buff *rep_skb;
407 struct cgroupstats *stats;
408 struct nlattr *na;
409 size_t size;
410 u32 fd;
411 struct fd f;
412
413 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
414 if (!na)
415 return -EINVAL;
416
417 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
418 f = fdget(fd);
419 if (!f.file)
420 return 0;
421
422 size = nla_total_size(sizeof(struct cgroupstats));
423
424 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
425 size);
426 if (rc < 0)
427 goto err;
428
429 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
430 sizeof(struct cgroupstats));
431 if (na == NULL) {
432 nlmsg_free(rep_skb);
433 rc = -EMSGSIZE;
434 goto err;
435 }
436
437 stats = nla_data(na);
438 memset(stats, 0, sizeof(*stats));
439
440 rc = cgroupstats_build(stats, f.file->f_path.dentry);
441 if (rc < 0) {
442 nlmsg_free(rep_skb);
443 goto err;
444 }
445
446 rc = send_reply(rep_skb, info);
447
448 err:
449 fdput(f);
450 return rc;
451 }
452
453 static int cmd_attr_register_cpumask(struct genl_info *info)
454 {
455 cpumask_var_t mask;
456 int rc;
457
458 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
459 return -ENOMEM;
460 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
461 if (rc < 0)
462 goto out;
463 rc = add_del_listener(info->snd_portid, mask, REGISTER);
464 out:
465 free_cpumask_var(mask);
466 return rc;
467 }
468
469 static int cmd_attr_deregister_cpumask(struct genl_info *info)
470 {
471 cpumask_var_t mask;
472 int rc;
473
474 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
475 return -ENOMEM;
476 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
477 if (rc < 0)
478 goto out;
479 rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
480 out:
481 free_cpumask_var(mask);
482 return rc;
483 }
484
485 static size_t taskstats_packet_size(void)
486 {
487 size_t size;
488
489 size = nla_total_size(sizeof(u32)) +
490 nla_total_size_64bit(sizeof(struct taskstats)) +
491 nla_total_size(0);
492
493 return size;
494 }
495
496 static int cmd_attr_pid(struct genl_info *info)
497 {
498 struct taskstats *stats;
499 struct sk_buff *rep_skb;
500 size_t size;
501 u32 pid;
502 int rc;
503
504 size = taskstats_packet_size();
505
506 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
507 if (rc < 0)
508 return rc;
509
510 rc = -EINVAL;
511 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
512 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
513 if (!stats)
514 goto err;
515
516 rc = fill_stats_for_pid(pid, stats);
517 if (rc < 0)
518 goto err;
519 return send_reply(rep_skb, info);
520 err:
521 nlmsg_free(rep_skb);
522 return rc;
523 }
524
525 static int cmd_attr_tgid(struct genl_info *info)
526 {
527 struct taskstats *stats;
528 struct sk_buff *rep_skb;
529 size_t size;
530 u32 tgid;
531 int rc;
532
533 size = taskstats_packet_size();
534
535 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
536 if (rc < 0)
537 return rc;
538
539 rc = -EINVAL;
540 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
541 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
542 if (!stats)
543 goto err;
544
545 rc = fill_stats_for_tgid(tgid, stats);
546 if (rc < 0)
547 goto err;
548 return send_reply(rep_skb, info);
549 err:
550 nlmsg_free(rep_skb);
551 return rc;
552 }
553
554 static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
555 {
556 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
557 return cmd_attr_register_cpumask(info);
558 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
559 return cmd_attr_deregister_cpumask(info);
560 else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
561 return cmd_attr_pid(info);
562 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
563 return cmd_attr_tgid(info);
564 else
565 return -EINVAL;
566 }
567
568 static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
569 {
570 struct signal_struct *sig = tsk->signal;
571 struct taskstats *stats;
572
573 if (sig->stats || thread_group_empty(tsk))
574 goto ret;
575
576 /* No problem if kmem_cache_zalloc() fails */
577 stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
578
579 spin_lock_irq(&tsk->sighand->siglock);
580 if (!sig->stats) {
581 sig->stats = stats;
582 stats = NULL;
583 }
584 spin_unlock_irq(&tsk->sighand->siglock);
585
586 if (stats)
587 kmem_cache_free(taskstats_cache, stats);
588 ret:
589 return sig->stats;
590 }
591
592 /* Send pid data out on exit */
593 void taskstats_exit(struct task_struct *tsk, int group_dead)
594 {
595 int rc;
596 struct listener_list *listeners;
597 struct taskstats *stats;
598 struct sk_buff *rep_skb;
599 size_t size;
600 int is_thread_group;
601
602 if (!family_registered)
603 return;
604
605 /*
606 * Size includes space for nested attributes
607 */
608 size = taskstats_packet_size();
609
610 is_thread_group = !!taskstats_tgid_alloc(tsk);
611 if (is_thread_group) {
612 /* PID + STATS + TGID + STATS */
613 size = 2 * size;
614 /* fill the tsk->signal->stats structure */
615 fill_tgid_exit(tsk);
616 }
617
618 listeners = raw_cpu_ptr(&listener_array);
619 if (list_empty(&listeners->list))
620 return;
621
622 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
623 if (rc < 0)
624 return;
625
626 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
627 task_pid_nr_ns(tsk, &init_pid_ns));
628 if (!stats)
629 goto err;
630
631 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
632
633 /*
634 * Doesn't matter if tsk is the leader or the last group member leaving
635 */
636 if (!is_thread_group || !group_dead)
637 goto send;
638
639 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
640 task_tgid_nr_ns(tsk, &init_pid_ns));
641 if (!stats)
642 goto err;
643
644 memcpy(stats, tsk->signal->stats, sizeof(*stats));
645
646 send:
647 send_cpu_listeners(rep_skb, listeners);
648 return;
649 err:
650 nlmsg_free(rep_skb);
651 }
652
653 static const struct genl_ops taskstats_ops[] = {
654 {
655 .cmd = TASKSTATS_CMD_GET,
656 .doit = taskstats_user_cmd,
657 .policy = taskstats_cmd_get_policy,
658 .flags = GENL_ADMIN_PERM,
659 },
660 {
661 .cmd = CGROUPSTATS_CMD_GET,
662 .doit = cgroupstats_user_cmd,
663 .policy = cgroupstats_cmd_get_policy,
664 },
665 };
666
667 static struct genl_family family __ro_after_init = {
668 .name = TASKSTATS_GENL_NAME,
669 .version = TASKSTATS_GENL_VERSION,
670 .maxattr = TASKSTATS_CMD_ATTR_MAX,
671 .module = THIS_MODULE,
672 .ops = taskstats_ops,
673 .n_ops = ARRAY_SIZE(taskstats_ops),
674 };
675
676 /* Needed early in initialization */
677 void __init taskstats_init_early(void)
678 {
679 unsigned int i;
680
681 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
682 for_each_possible_cpu(i) {
683 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
684 init_rwsem(&(per_cpu(listener_array, i).sem));
685 }
686 }
687
688 static int __init taskstats_init(void)
689 {
690 int rc;
691
692 rc = genl_register_family(&family);
693 if (rc)
694 return rc;
695
696 family_registered = 1;
697 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
698 return 0;
699 }
700
701 /*
702 * late initcall ensures initialization of statistics collection
703 * mechanisms precedes initialization of the taskstats interface
704 */
705 late_initcall(taskstats_init);