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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * taskstats.c - Export per-task statistics to userland
4 *
5 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
6 * (C) Balbir Singh, IBM Corp. 2006
7 */
8
9#include <linux/kernel.h>
10#include <linux/taskstats_kern.h>
11#include <linux/tsacct_kern.h>
12#include <linux/acct.h>
13#include <linux/delayacct.h>
14#include <linux/cpumask.h>
15#include <linux/percpu.h>
16#include <linux/slab.h>
17#include <linux/cgroupstats.h>
18#include <linux/cgroup.h>
19#include <linux/fs.h>
20#include <linux/file.h>
21#include <linux/pid_namespace.h>
22#include <net/genetlink.h>
23#include <linux/atomic.h>
24#include <linux/sched/cputime.h>
25
26/*
27 * Maximum length of a cpumask that can be specified in
28 * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
29 */
30#define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
31
32static DEFINE_PER_CPU(__u32, taskstats_seqnum);
33static int family_registered;
34struct kmem_cache *taskstats_cache;
35
36static struct genl_family family;
37
38static const struct nla_policy taskstats_cmd_get_policy[] = {
39 [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
40 [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
41 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
42 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
43
44static const struct nla_policy cgroupstats_cmd_get_policy[] = {
45 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
46};
47
48struct listener {
49 struct list_head list;
50 pid_t pid;
51 char valid;
52};
53
54struct listener_list {
55 struct rw_semaphore sem;
56 struct list_head list;
57};
58static DEFINE_PER_CPU(struct listener_list, listener_array);
59
60enum actions {
61 REGISTER,
62 DEREGISTER,
63 CPU_DONT_CARE
64};
65
66static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
67 size_t size)
68{
69 struct sk_buff *skb;
70 void *reply;
71
72 /*
73 * If new attributes are added, please revisit this allocation
74 */
75 skb = genlmsg_new(size, GFP_KERNEL);
76 if (!skb)
77 return -ENOMEM;
78
79 if (!info) {
80 int seq = this_cpu_inc_return(taskstats_seqnum) - 1;
81
82 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
83 } else
84 reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
85 if (reply == NULL) {
86 nlmsg_free(skb);
87 return -EINVAL;
88 }
89
90 *skbp = skb;
91 return 0;
92}
93
94/*
95 * Send taskstats data in @skb to listener with nl_pid @pid
96 */
97static int send_reply(struct sk_buff *skb, struct genl_info *info)
98{
99 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
100 void *reply = genlmsg_data(genlhdr);
101
102 genlmsg_end(skb, reply);
103
104 return genlmsg_reply(skb, info);
105}
106
107/*
108 * Send taskstats data in @skb to listeners registered for @cpu's exit data
109 */
110static void send_cpu_listeners(struct sk_buff *skb,
111 struct listener_list *listeners)
112{
113 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
114 struct listener *s, *tmp;
115 struct sk_buff *skb_next, *skb_cur = skb;
116 void *reply = genlmsg_data(genlhdr);
117 int delcount = 0;
118
119 genlmsg_end(skb, reply);
120
121 down_read(&listeners->sem);
122 list_for_each_entry(s, &listeners->list, list) {
123 int rc;
124
125 skb_next = NULL;
126 if (!list_is_last(&s->list, &listeners->list)) {
127 skb_next = skb_clone(skb_cur, GFP_KERNEL);
128 if (!skb_next)
129 break;
130 }
131 rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
132 if (rc == -ECONNREFUSED) {
133 s->valid = 0;
134 delcount++;
135 }
136 skb_cur = skb_next;
137 }
138 up_read(&listeners->sem);
139
140 if (skb_cur)
141 nlmsg_free(skb_cur);
142
143 if (!delcount)
144 return;
145
146 /* Delete invalidated entries */
147 down_write(&listeners->sem);
148 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
149 if (!s->valid) {
150 list_del(&s->list);
151 kfree(s);
152 }
153 }
154 up_write(&listeners->sem);
155}
156
157static void exe_add_tsk(struct taskstats *stats, struct task_struct *tsk)
158{
159 /* No idea if I'm allowed to access that here, now. */
160 struct file *exe_file = get_task_exe_file(tsk);
161
162 if (exe_file) {
163 /* Following cp_new_stat64() in stat.c . */
164 stats->ac_exe_dev =
165 huge_encode_dev(exe_file->f_inode->i_sb->s_dev);
166 stats->ac_exe_inode = exe_file->f_inode->i_ino;
167 fput(exe_file);
168 } else {
169 stats->ac_exe_dev = 0;
170 stats->ac_exe_inode = 0;
171 }
172}
173
174static void fill_stats(struct user_namespace *user_ns,
175 struct pid_namespace *pid_ns,
176 struct task_struct *tsk, struct taskstats *stats)
177{
178 memset(stats, 0, sizeof(*stats));
179 /*
180 * Each accounting subsystem adds calls to its functions to
181 * fill in relevant parts of struct taskstsats as follows
182 *
183 * per-task-foo(stats, tsk);
184 */
185
186 delayacct_add_tsk(stats, tsk);
187
188 /* fill in basic acct fields */
189 stats->version = TASKSTATS_VERSION;
190 stats->nvcsw = tsk->nvcsw;
191 stats->nivcsw = tsk->nivcsw;
192 bacct_add_tsk(user_ns, pid_ns, stats, tsk);
193
194 /* fill in extended acct fields */
195 xacct_add_tsk(stats, tsk);
196
197 /* add executable info */
198 exe_add_tsk(stats, tsk);
199}
200
201static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
202{
203 struct task_struct *tsk;
204
205 tsk = find_get_task_by_vpid(pid);
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 u64 delta, utime, stime;
219 u64 start_time;
220
221 /*
222 * Add additional stats from live tasks except zombie thread group
223 * leaders who are already counted with the dead tasks
224 */
225 rcu_read_lock();
226 first = find_task_by_vpid(tgid);
227
228 if (!first || !lock_task_sighand(first, &flags))
229 goto out;
230
231 if (first->signal->stats)
232 memcpy(stats, first->signal->stats, sizeof(*stats));
233 else
234 memset(stats, 0, sizeof(*stats));
235
236 tsk = first;
237 start_time = ktime_get_ns();
238 do {
239 if (tsk->exit_state)
240 continue;
241 /*
242 * Accounting subsystem can call its functions here to
243 * fill in relevant parts of struct taskstsats as follows
244 *
245 * per-task-foo(stats, tsk);
246 */
247 delayacct_add_tsk(stats, tsk);
248
249 /* calculate task elapsed time in nsec */
250 delta = start_time - tsk->start_time;
251 /* Convert to micro seconds */
252 do_div(delta, NSEC_PER_USEC);
253 stats->ac_etime += delta;
254
255 task_cputime(tsk, &utime, &stime);
256 stats->ac_utime += div_u64(utime, NSEC_PER_USEC);
257 stats->ac_stime += div_u64(stime, NSEC_PER_USEC);
258
259 stats->nvcsw += tsk->nvcsw;
260 stats->nivcsw += tsk->nivcsw;
261 } while_each_thread(first, tsk);
262
263 unlock_task_sighand(first, &flags);
264 rc = 0;
265out:
266 rcu_read_unlock();
267
268 stats->version = TASKSTATS_VERSION;
269 /*
270 * Accounting subsystems can also add calls here to modify
271 * fields of taskstats.
272 */
273 return rc;
274}
275
276static void fill_tgid_exit(struct task_struct *tsk)
277{
278 unsigned long flags;
279
280 spin_lock_irqsave(&tsk->sighand->siglock, flags);
281 if (!tsk->signal->stats)
282 goto ret;
283
284 /*
285 * Each accounting subsystem calls its functions here to
286 * accumalate its per-task stats for tsk, into the per-tgid structure
287 *
288 * per-task-foo(tsk->signal->stats, tsk);
289 */
290 delayacct_add_tsk(tsk->signal->stats, tsk);
291ret:
292 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
293 return;
294}
295
296static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
297{
298 struct listener_list *listeners;
299 struct listener *s, *tmp, *s2;
300 unsigned int cpu;
301 int ret = 0;
302
303 if (!cpumask_subset(mask, cpu_possible_mask))
304 return -EINVAL;
305
306 if (current_user_ns() != &init_user_ns)
307 return -EINVAL;
308
309 if (task_active_pid_ns(current) != &init_pid_ns)
310 return -EINVAL;
311
312 if (isadd == REGISTER) {
313 for_each_cpu(cpu, mask) {
314 s = kmalloc_node(sizeof(struct listener),
315 GFP_KERNEL, cpu_to_node(cpu));
316 if (!s) {
317 ret = -ENOMEM;
318 goto cleanup;
319 }
320 s->pid = pid;
321 s->valid = 1;
322
323 listeners = &per_cpu(listener_array, cpu);
324 down_write(&listeners->sem);
325 list_for_each_entry(s2, &listeners->list, list) {
326 if (s2->pid == pid && s2->valid)
327 goto exists;
328 }
329 list_add(&s->list, &listeners->list);
330 s = NULL;
331exists:
332 up_write(&listeners->sem);
333 kfree(s); /* nop if NULL */
334 }
335 return 0;
336 }
337
338 /* Deregister or cleanup */
339cleanup:
340 for_each_cpu(cpu, mask) {
341 listeners = &per_cpu(listener_array, cpu);
342 down_write(&listeners->sem);
343 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
344 if (s->pid == pid) {
345 list_del(&s->list);
346 kfree(s);
347 break;
348 }
349 }
350 up_write(&listeners->sem);
351 }
352 return ret;
353}
354
355static int parse(struct nlattr *na, struct cpumask *mask)
356{
357 char *data;
358 int len;
359 int ret;
360
361 if (na == NULL)
362 return 1;
363 len = nla_len(na);
364 if (len > TASKSTATS_CPUMASK_MAXLEN)
365 return -E2BIG;
366 if (len < 1)
367 return -EINVAL;
368 data = kmalloc(len, GFP_KERNEL);
369 if (!data)
370 return -ENOMEM;
371 nla_strscpy(data, na, len);
372 ret = cpulist_parse(data, mask);
373 kfree(data);
374 return ret;
375}
376
377static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
378{
379 struct nlattr *na, *ret;
380 int aggr;
381
382 aggr = (type == TASKSTATS_TYPE_PID)
383 ? TASKSTATS_TYPE_AGGR_PID
384 : TASKSTATS_TYPE_AGGR_TGID;
385
386 na = nla_nest_start_noflag(skb, aggr);
387 if (!na)
388 goto err;
389
390 if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
391 nla_nest_cancel(skb, na);
392 goto err;
393 }
394 ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
395 sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
396 if (!ret) {
397 nla_nest_cancel(skb, na);
398 goto err;
399 }
400 nla_nest_end(skb, na);
401
402 return nla_data(ret);
403err:
404 return NULL;
405}
406
407static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
408{
409 int rc = 0;
410 struct sk_buff *rep_skb;
411 struct cgroupstats *stats;
412 struct nlattr *na;
413 size_t size;
414 u32 fd;
415 struct fd f;
416
417 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
418 if (!na)
419 return -EINVAL;
420
421 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
422 f = fdget(fd);
423 if (!f.file)
424 return 0;
425
426 size = nla_total_size(sizeof(struct cgroupstats));
427
428 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
429 size);
430 if (rc < 0)
431 goto err;
432
433 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
434 sizeof(struct cgroupstats));
435 if (na == NULL) {
436 nlmsg_free(rep_skb);
437 rc = -EMSGSIZE;
438 goto err;
439 }
440
441 stats = nla_data(na);
442 memset(stats, 0, sizeof(*stats));
443
444 rc = cgroupstats_build(stats, f.file->f_path.dentry);
445 if (rc < 0) {
446 nlmsg_free(rep_skb);
447 goto err;
448 }
449
450 rc = send_reply(rep_skb, info);
451
452err:
453 fdput(f);
454 return rc;
455}
456
457static int cmd_attr_register_cpumask(struct genl_info *info)
458{
459 cpumask_var_t mask;
460 int rc;
461
462 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
463 return -ENOMEM;
464 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
465 if (rc < 0)
466 goto out;
467 rc = add_del_listener(info->snd_portid, mask, REGISTER);
468out:
469 free_cpumask_var(mask);
470 return rc;
471}
472
473static int cmd_attr_deregister_cpumask(struct genl_info *info)
474{
475 cpumask_var_t mask;
476 int rc;
477
478 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
479 return -ENOMEM;
480 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
481 if (rc < 0)
482 goto out;
483 rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
484out:
485 free_cpumask_var(mask);
486 return rc;
487}
488
489static size_t taskstats_packet_size(void)
490{
491 size_t size;
492
493 size = nla_total_size(sizeof(u32)) +
494 nla_total_size_64bit(sizeof(struct taskstats)) +
495 nla_total_size(0);
496
497 return size;
498}
499
500static int cmd_attr_pid(struct genl_info *info)
501{
502 struct taskstats *stats;
503 struct sk_buff *rep_skb;
504 size_t size;
505 u32 pid;
506 int rc;
507
508 size = taskstats_packet_size();
509
510 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
511 if (rc < 0)
512 return rc;
513
514 rc = -EINVAL;
515 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
516 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
517 if (!stats)
518 goto err;
519
520 rc = fill_stats_for_pid(pid, stats);
521 if (rc < 0)
522 goto err;
523 return send_reply(rep_skb, info);
524err:
525 nlmsg_free(rep_skb);
526 return rc;
527}
528
529static int cmd_attr_tgid(struct genl_info *info)
530{
531 struct taskstats *stats;
532 struct sk_buff *rep_skb;
533 size_t size;
534 u32 tgid;
535 int rc;
536
537 size = taskstats_packet_size();
538
539 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
540 if (rc < 0)
541 return rc;
542
543 rc = -EINVAL;
544 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
545 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
546 if (!stats)
547 goto err;
548
549 rc = fill_stats_for_tgid(tgid, stats);
550 if (rc < 0)
551 goto err;
552 return send_reply(rep_skb, info);
553err:
554 nlmsg_free(rep_skb);
555 return rc;
556}
557
558static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
559{
560 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
561 return cmd_attr_register_cpumask(info);
562 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
563 return cmd_attr_deregister_cpumask(info);
564 else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
565 return cmd_attr_pid(info);
566 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
567 return cmd_attr_tgid(info);
568 else
569 return -EINVAL;
570}
571
572static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
573{
574 struct signal_struct *sig = tsk->signal;
575 struct taskstats *stats_new, *stats;
576
577 /* Pairs with smp_store_release() below. */
578 stats = smp_load_acquire(&sig->stats);
579 if (stats || thread_group_empty(tsk))
580 return stats;
581
582 /* No problem if kmem_cache_zalloc() fails */
583 stats_new = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
584
585 spin_lock_irq(&tsk->sighand->siglock);
586 stats = sig->stats;
587 if (!stats) {
588 /*
589 * Pairs with smp_store_release() above and order the
590 * kmem_cache_zalloc().
591 */
592 smp_store_release(&sig->stats, stats_new);
593 stats = stats_new;
594 stats_new = NULL;
595 }
596 spin_unlock_irq(&tsk->sighand->siglock);
597
598 if (stats_new)
599 kmem_cache_free(taskstats_cache, stats_new);
600
601 return stats;
602}
603
604/* Send pid data out on exit */
605void taskstats_exit(struct task_struct *tsk, int group_dead)
606{
607 int rc;
608 struct listener_list *listeners;
609 struct taskstats *stats;
610 struct sk_buff *rep_skb;
611 size_t size;
612 int is_thread_group;
613
614 if (!family_registered)
615 return;
616
617 /*
618 * Size includes space for nested attributes
619 */
620 size = taskstats_packet_size();
621
622 is_thread_group = !!taskstats_tgid_alloc(tsk);
623 if (is_thread_group) {
624 /* PID + STATS + TGID + STATS */
625 size = 2 * size;
626 /* fill the tsk->signal->stats structure */
627 fill_tgid_exit(tsk);
628 }
629
630 listeners = raw_cpu_ptr(&listener_array);
631 if (list_empty(&listeners->list))
632 return;
633
634 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
635 if (rc < 0)
636 return;
637
638 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
639 task_pid_nr_ns(tsk, &init_pid_ns));
640 if (!stats)
641 goto err;
642
643 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
644 if (group_dead)
645 stats->ac_flag |= AGROUP;
646
647 /*
648 * Doesn't matter if tsk is the leader or the last group member leaving
649 */
650 if (!is_thread_group || !group_dead)
651 goto send;
652
653 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
654 task_tgid_nr_ns(tsk, &init_pid_ns));
655 if (!stats)
656 goto err;
657
658 memcpy(stats, tsk->signal->stats, sizeof(*stats));
659
660send:
661 send_cpu_listeners(rep_skb, listeners);
662 return;
663err:
664 nlmsg_free(rep_skb);
665}
666
667static const struct genl_ops taskstats_ops[] = {
668 {
669 .cmd = TASKSTATS_CMD_GET,
670 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
671 .doit = taskstats_user_cmd,
672 .policy = taskstats_cmd_get_policy,
673 .maxattr = ARRAY_SIZE(taskstats_cmd_get_policy) - 1,
674 .flags = GENL_ADMIN_PERM,
675 },
676 {
677 .cmd = CGROUPSTATS_CMD_GET,
678 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
679 .doit = cgroupstats_user_cmd,
680 .policy = cgroupstats_cmd_get_policy,
681 .maxattr = ARRAY_SIZE(cgroupstats_cmd_get_policy) - 1,
682 },
683};
684
685static struct genl_family family __ro_after_init = {
686 .name = TASKSTATS_GENL_NAME,
687 .version = TASKSTATS_GENL_VERSION,
688 .module = THIS_MODULE,
689 .ops = taskstats_ops,
690 .n_ops = ARRAY_SIZE(taskstats_ops),
691 .resv_start_op = CGROUPSTATS_CMD_GET + 1,
692 .netnsok = true,
693};
694
695/* Needed early in initialization */
696void __init taskstats_init_early(void)
697{
698 unsigned int i;
699
700 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
701 for_each_possible_cpu(i) {
702 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
703 init_rwsem(&(per_cpu(listener_array, i).sem));
704 }
705}
706
707static int __init taskstats_init(void)
708{
709 int rc;
710
711 rc = genl_register_family(&family);
712 if (rc)
713 return rc;
714
715 family_registered = 1;
716 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
717 return 0;
718}
719
720/*
721 * late initcall ensures initialization of statistics collection
722 * mechanisms precedes initialization of the taskstats interface
723 */
724late_initcall(taskstats_init);
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
46static const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {
47 [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
48 [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
49 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
50 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
51
52/*
53 * We have to use TASKSTATS_CMD_ATTR_MAX here, it is the maxattr in the family.
54 * Make sure they are always aligned.
55 */
56static const struct nla_policy cgroupstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {
57 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
58};
59
60struct listener {
61 struct list_head list;
62 pid_t pid;
63 char valid;
64};
65
66struct listener_list {
67 struct rw_semaphore sem;
68 struct list_head list;
69};
70static DEFINE_PER_CPU(struct listener_list, listener_array);
71
72enum actions {
73 REGISTER,
74 DEREGISTER,
75 CPU_DONT_CARE
76};
77
78static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
79 size_t size)
80{
81 struct sk_buff *skb;
82 void *reply;
83
84 /*
85 * If new attributes are added, please revisit this allocation
86 */
87 skb = genlmsg_new(size, GFP_KERNEL);
88 if (!skb)
89 return -ENOMEM;
90
91 if (!info) {
92 int seq = this_cpu_inc_return(taskstats_seqnum) - 1;
93
94 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
95 } else
96 reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
97 if (reply == NULL) {
98 nlmsg_free(skb);
99 return -EINVAL;
100 }
101
102 *skbp = skb;
103 return 0;
104}
105
106/*
107 * Send taskstats data in @skb to listener with nl_pid @pid
108 */
109static int send_reply(struct sk_buff *skb, struct genl_info *info)
110{
111 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
112 void *reply = genlmsg_data(genlhdr);
113
114 genlmsg_end(skb, reply);
115
116 return genlmsg_reply(skb, info);
117}
118
119/*
120 * Send taskstats data in @skb to listeners registered for @cpu's exit data
121 */
122static void send_cpu_listeners(struct sk_buff *skb,
123 struct listener_list *listeners)
124{
125 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
126 struct listener *s, *tmp;
127 struct sk_buff *skb_next, *skb_cur = skb;
128 void *reply = genlmsg_data(genlhdr);
129 int rc, delcount = 0;
130
131 genlmsg_end(skb, reply);
132
133 rc = 0;
134 down_read(&listeners->sem);
135 list_for_each_entry(s, &listeners->list, list) {
136 skb_next = NULL;
137 if (!list_is_last(&s->list, &listeners->list)) {
138 skb_next = skb_clone(skb_cur, GFP_KERNEL);
139 if (!skb_next)
140 break;
141 }
142 rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
143 if (rc == -ECONNREFUSED) {
144 s->valid = 0;
145 delcount++;
146 }
147 skb_cur = skb_next;
148 }
149 up_read(&listeners->sem);
150
151 if (skb_cur)
152 nlmsg_free(skb_cur);
153
154 if (!delcount)
155 return;
156
157 /* Delete invalidated entries */
158 down_write(&listeners->sem);
159 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
160 if (!s->valid) {
161 list_del(&s->list);
162 kfree(s);
163 }
164 }
165 up_write(&listeners->sem);
166}
167
168static void fill_stats(struct user_namespace *user_ns,
169 struct pid_namespace *pid_ns,
170 struct task_struct *tsk, struct taskstats *stats)
171{
172 memset(stats, 0, sizeof(*stats));
173 /*
174 * Each accounting subsystem adds calls to its functions to
175 * fill in relevant parts of struct taskstsats as follows
176 *
177 * per-task-foo(stats, tsk);
178 */
179
180 delayacct_add_tsk(stats, tsk);
181
182 /* fill in basic acct fields */
183 stats->version = TASKSTATS_VERSION;
184 stats->nvcsw = tsk->nvcsw;
185 stats->nivcsw = tsk->nivcsw;
186 bacct_add_tsk(user_ns, pid_ns, stats, tsk);
187
188 /* fill in extended acct fields */
189 xacct_add_tsk(stats, tsk);
190}
191
192static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
193{
194 struct task_struct *tsk;
195
196 rcu_read_lock();
197 tsk = find_task_by_vpid(pid);
198 if (tsk)
199 get_task_struct(tsk);
200 rcu_read_unlock();
201 if (!tsk)
202 return -ESRCH;
203 fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);
204 put_task_struct(tsk);
205 return 0;
206}
207
208static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats)
209{
210 struct task_struct *tsk, *first;
211 unsigned long flags;
212 int rc = -ESRCH;
213
214 /*
215 * Add additional stats from live tasks except zombie thread group
216 * leaders who are already counted with the dead tasks
217 */
218 rcu_read_lock();
219 first = find_task_by_vpid(tgid);
220
221 if (!first || !lock_task_sighand(first, &flags))
222 goto out;
223
224 if (first->signal->stats)
225 memcpy(stats, first->signal->stats, sizeof(*stats));
226 else
227 memset(stats, 0, sizeof(*stats));
228
229 tsk = first;
230 do {
231 if (tsk->exit_state)
232 continue;
233 /*
234 * Accounting subsystem can call its functions here to
235 * fill in relevant parts of struct taskstsats as follows
236 *
237 * per-task-foo(stats, tsk);
238 */
239 delayacct_add_tsk(stats, tsk);
240
241 stats->nvcsw += tsk->nvcsw;
242 stats->nivcsw += tsk->nivcsw;
243 } while_each_thread(first, tsk);
244
245 unlock_task_sighand(first, &flags);
246 rc = 0;
247out:
248 rcu_read_unlock();
249
250 stats->version = TASKSTATS_VERSION;
251 /*
252 * Accounting subsystems can also add calls here to modify
253 * fields of taskstats.
254 */
255 return rc;
256}
257
258static void fill_tgid_exit(struct task_struct *tsk)
259{
260 unsigned long flags;
261
262 spin_lock_irqsave(&tsk->sighand->siglock, flags);
263 if (!tsk->signal->stats)
264 goto ret;
265
266 /*
267 * Each accounting subsystem calls its functions here to
268 * accumalate its per-task stats for tsk, into the per-tgid structure
269 *
270 * per-task-foo(tsk->signal->stats, tsk);
271 */
272 delayacct_add_tsk(tsk->signal->stats, tsk);
273ret:
274 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
275 return;
276}
277
278static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
279{
280 struct listener_list *listeners;
281 struct listener *s, *tmp, *s2;
282 unsigned int cpu;
283 int ret = 0;
284
285 if (!cpumask_subset(mask, cpu_possible_mask))
286 return -EINVAL;
287
288 if (current_user_ns() != &init_user_ns)
289 return -EINVAL;
290
291 if (task_active_pid_ns(current) != &init_pid_ns)
292 return -EINVAL;
293
294 if (isadd == REGISTER) {
295 for_each_cpu(cpu, mask) {
296 s = kmalloc_node(sizeof(struct listener),
297 GFP_KERNEL, cpu_to_node(cpu));
298 if (!s) {
299 ret = -ENOMEM;
300 goto cleanup;
301 }
302 s->pid = pid;
303 s->valid = 1;
304
305 listeners = &per_cpu(listener_array, cpu);
306 down_write(&listeners->sem);
307 list_for_each_entry(s2, &listeners->list, list) {
308 if (s2->pid == pid && s2->valid)
309 goto exists;
310 }
311 list_add(&s->list, &listeners->list);
312 s = NULL;
313exists:
314 up_write(&listeners->sem);
315 kfree(s); /* nop if NULL */
316 }
317 return 0;
318 }
319
320 /* Deregister or cleanup */
321cleanup:
322 for_each_cpu(cpu, mask) {
323 listeners = &per_cpu(listener_array, cpu);
324 down_write(&listeners->sem);
325 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
326 if (s->pid == pid) {
327 list_del(&s->list);
328 kfree(s);
329 break;
330 }
331 }
332 up_write(&listeners->sem);
333 }
334 return ret;
335}
336
337static int parse(struct nlattr *na, struct cpumask *mask)
338{
339 char *data;
340 int len;
341 int ret;
342
343 if (na == NULL)
344 return 1;
345 len = nla_len(na);
346 if (len > TASKSTATS_CPUMASK_MAXLEN)
347 return -E2BIG;
348 if (len < 1)
349 return -EINVAL;
350 data = kmalloc(len, GFP_KERNEL);
351 if (!data)
352 return -ENOMEM;
353 nla_strlcpy(data, na, len);
354 ret = cpulist_parse(data, mask);
355 kfree(data);
356 return ret;
357}
358
359static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
360{
361 struct nlattr *na, *ret;
362 int aggr;
363
364 aggr = (type == TASKSTATS_TYPE_PID)
365 ? TASKSTATS_TYPE_AGGR_PID
366 : TASKSTATS_TYPE_AGGR_TGID;
367
368 na = nla_nest_start(skb, aggr);
369 if (!na)
370 goto err;
371
372 if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
373 nla_nest_cancel(skb, na);
374 goto err;
375 }
376 ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
377 sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
378 if (!ret) {
379 nla_nest_cancel(skb, na);
380 goto err;
381 }
382 nla_nest_end(skb, na);
383
384 return nla_data(ret);
385err:
386 return NULL;
387}
388
389static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
390{
391 int rc = 0;
392 struct sk_buff *rep_skb;
393 struct cgroupstats *stats;
394 struct nlattr *na;
395 size_t size;
396 u32 fd;
397 struct fd f;
398
399 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
400 if (!na)
401 return -EINVAL;
402
403 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
404 f = fdget(fd);
405 if (!f.file)
406 return 0;
407
408 size = nla_total_size(sizeof(struct cgroupstats));
409
410 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
411 size);
412 if (rc < 0)
413 goto err;
414
415 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
416 sizeof(struct cgroupstats));
417 if (na == NULL) {
418 nlmsg_free(rep_skb);
419 rc = -EMSGSIZE;
420 goto err;
421 }
422
423 stats = nla_data(na);
424 memset(stats, 0, sizeof(*stats));
425
426 rc = cgroupstats_build(stats, f.file->f_path.dentry);
427 if (rc < 0) {
428 nlmsg_free(rep_skb);
429 goto err;
430 }
431
432 rc = send_reply(rep_skb, info);
433
434err:
435 fdput(f);
436 return rc;
437}
438
439static int cmd_attr_register_cpumask(struct genl_info *info)
440{
441 cpumask_var_t mask;
442 int rc;
443
444 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
445 return -ENOMEM;
446 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
447 if (rc < 0)
448 goto out;
449 rc = add_del_listener(info->snd_portid, mask, REGISTER);
450out:
451 free_cpumask_var(mask);
452 return rc;
453}
454
455static int cmd_attr_deregister_cpumask(struct genl_info *info)
456{
457 cpumask_var_t mask;
458 int rc;
459
460 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
461 return -ENOMEM;
462 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
463 if (rc < 0)
464 goto out;
465 rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
466out:
467 free_cpumask_var(mask);
468 return rc;
469}
470
471static size_t taskstats_packet_size(void)
472{
473 size_t size;
474
475 size = nla_total_size(sizeof(u32)) +
476 nla_total_size_64bit(sizeof(struct taskstats)) +
477 nla_total_size(0);
478
479 return size;
480}
481
482static int cmd_attr_pid(struct genl_info *info)
483{
484 struct taskstats *stats;
485 struct sk_buff *rep_skb;
486 size_t size;
487 u32 pid;
488 int rc;
489
490 size = taskstats_packet_size();
491
492 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
493 if (rc < 0)
494 return rc;
495
496 rc = -EINVAL;
497 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
498 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
499 if (!stats)
500 goto err;
501
502 rc = fill_stats_for_pid(pid, stats);
503 if (rc < 0)
504 goto err;
505 return send_reply(rep_skb, info);
506err:
507 nlmsg_free(rep_skb);
508 return rc;
509}
510
511static int cmd_attr_tgid(struct genl_info *info)
512{
513 struct taskstats *stats;
514 struct sk_buff *rep_skb;
515 size_t size;
516 u32 tgid;
517 int rc;
518
519 size = taskstats_packet_size();
520
521 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
522 if (rc < 0)
523 return rc;
524
525 rc = -EINVAL;
526 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
527 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
528 if (!stats)
529 goto err;
530
531 rc = fill_stats_for_tgid(tgid, stats);
532 if (rc < 0)
533 goto err;
534 return send_reply(rep_skb, info);
535err:
536 nlmsg_free(rep_skb);
537 return rc;
538}
539
540static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
541{
542 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
543 return cmd_attr_register_cpumask(info);
544 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
545 return cmd_attr_deregister_cpumask(info);
546 else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
547 return cmd_attr_pid(info);
548 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
549 return cmd_attr_tgid(info);
550 else
551 return -EINVAL;
552}
553
554static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
555{
556 struct signal_struct *sig = tsk->signal;
557 struct taskstats *stats;
558
559 if (sig->stats || thread_group_empty(tsk))
560 goto ret;
561
562 /* No problem if kmem_cache_zalloc() fails */
563 stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
564
565 spin_lock_irq(&tsk->sighand->siglock);
566 if (!sig->stats) {
567 sig->stats = stats;
568 stats = NULL;
569 }
570 spin_unlock_irq(&tsk->sighand->siglock);
571
572 if (stats)
573 kmem_cache_free(taskstats_cache, stats);
574ret:
575 return sig->stats;
576}
577
578/* Send pid data out on exit */
579void taskstats_exit(struct task_struct *tsk, int group_dead)
580{
581 int rc;
582 struct listener_list *listeners;
583 struct taskstats *stats;
584 struct sk_buff *rep_skb;
585 size_t size;
586 int is_thread_group;
587
588 if (!family_registered)
589 return;
590
591 /*
592 * Size includes space for nested attributes
593 */
594 size = taskstats_packet_size();
595
596 is_thread_group = !!taskstats_tgid_alloc(tsk);
597 if (is_thread_group) {
598 /* PID + STATS + TGID + STATS */
599 size = 2 * size;
600 /* fill the tsk->signal->stats structure */
601 fill_tgid_exit(tsk);
602 }
603
604 listeners = raw_cpu_ptr(&listener_array);
605 if (list_empty(&listeners->list))
606 return;
607
608 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
609 if (rc < 0)
610 return;
611
612 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
613 task_pid_nr_ns(tsk, &init_pid_ns));
614 if (!stats)
615 goto err;
616
617 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
618
619 /*
620 * Doesn't matter if tsk is the leader or the last group member leaving
621 */
622 if (!is_thread_group || !group_dead)
623 goto send;
624
625 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
626 task_tgid_nr_ns(tsk, &init_pid_ns));
627 if (!stats)
628 goto err;
629
630 memcpy(stats, tsk->signal->stats, sizeof(*stats));
631
632send:
633 send_cpu_listeners(rep_skb, listeners);
634 return;
635err:
636 nlmsg_free(rep_skb);
637}
638
639static const struct genl_ops taskstats_ops[] = {
640 {
641 .cmd = TASKSTATS_CMD_GET,
642 .doit = taskstats_user_cmd,
643 .policy = taskstats_cmd_get_policy,
644 .flags = GENL_ADMIN_PERM,
645 },
646 {
647 .cmd = CGROUPSTATS_CMD_GET,
648 .doit = cgroupstats_user_cmd,
649 .policy = cgroupstats_cmd_get_policy,
650 },
651};
652
653static struct genl_family family __ro_after_init = {
654 .name = TASKSTATS_GENL_NAME,
655 .version = TASKSTATS_GENL_VERSION,
656 .maxattr = TASKSTATS_CMD_ATTR_MAX,
657 .module = THIS_MODULE,
658 .ops = taskstats_ops,
659 .n_ops = ARRAY_SIZE(taskstats_ops),
660};
661
662/* Needed early in initialization */
663void __init taskstats_init_early(void)
664{
665 unsigned int i;
666
667 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
668 for_each_possible_cpu(i) {
669 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
670 init_rwsem(&(per_cpu(listener_array, i).sem));
671 }
672}
673
674static int __init taskstats_init(void)
675{
676 int rc;
677
678 rc = genl_register_family(&family);
679 if (rc)
680 return rc;
681
682 family_registered = 1;
683 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
684 return 0;
685}
686
687/*
688 * late initcall ensures initialization of statistics collection
689 * mechanisms precedes initialization of the taskstats interface
690 */
691late_initcall(taskstats_init);