Loading...
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
57static const struct nla_policy cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] = {
58 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
59};
60
61struct listener {
62 struct list_head list;
63 pid_t pid;
64 char valid;
65};
66
67struct listener_list {
68 struct rw_semaphore sem;
69 struct list_head list;
70};
71static DEFINE_PER_CPU(struct listener_list, listener_array);
72
73enum actions {
74 REGISTER,
75 DEREGISTER,
76 CPU_DONT_CARE
77};
78
79static 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 */
110static 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 */
123static 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
169static 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
193static 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
209static 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
215 /*
216 * Add additional stats from live tasks except zombie thread group
217 * leaders who are already counted with the dead tasks
218 */
219 rcu_read_lock();
220 first = find_task_by_vpid(tgid);
221
222 if (!first || !lock_task_sighand(first, &flags))
223 goto out;
224
225 if (first->signal->stats)
226 memcpy(stats, first->signal->stats, sizeof(*stats));
227 else
228 memset(stats, 0, sizeof(*stats));
229
230 tsk = first;
231 do {
232 if (tsk->exit_state)
233 continue;
234 /*
235 * Accounting subsystem can call its functions here to
236 * fill in relevant parts of struct taskstsats as follows
237 *
238 * per-task-foo(stats, tsk);
239 */
240 delayacct_add_tsk(stats, tsk);
241
242 stats->nvcsw += tsk->nvcsw;
243 stats->nivcsw += tsk->nivcsw;
244 } while_each_thread(first, tsk);
245
246 unlock_task_sighand(first, &flags);
247 rc = 0;
248out:
249 rcu_read_unlock();
250
251 stats->version = TASKSTATS_VERSION;
252 /*
253 * Accounting subsystems can also add calls here to modify
254 * fields of taskstats.
255 */
256 return rc;
257}
258
259static void fill_tgid_exit(struct task_struct *tsk)
260{
261 unsigned long flags;
262
263 spin_lock_irqsave(&tsk->sighand->siglock, flags);
264 if (!tsk->signal->stats)
265 goto ret;
266
267 /*
268 * Each accounting subsystem calls its functions here to
269 * accumalate its per-task stats for tsk, into the per-tgid structure
270 *
271 * per-task-foo(tsk->signal->stats, tsk);
272 */
273 delayacct_add_tsk(tsk->signal->stats, tsk);
274ret:
275 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
276 return;
277}
278
279static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
280{
281 struct listener_list *listeners;
282 struct listener *s, *tmp, *s2;
283 unsigned int cpu;
284 int ret = 0;
285
286 if (!cpumask_subset(mask, cpu_possible_mask))
287 return -EINVAL;
288
289 if (current_user_ns() != &init_user_ns)
290 return -EINVAL;
291
292 if (task_active_pid_ns(current) != &init_pid_ns)
293 return -EINVAL;
294
295 if (isadd == REGISTER) {
296 for_each_cpu(cpu, mask) {
297 s = kmalloc_node(sizeof(struct listener),
298 GFP_KERNEL, cpu_to_node(cpu));
299 if (!s) {
300 ret = -ENOMEM;
301 goto cleanup;
302 }
303 s->pid = pid;
304 s->valid = 1;
305
306 listeners = &per_cpu(listener_array, cpu);
307 down_write(&listeners->sem);
308 list_for_each_entry(s2, &listeners->list, list) {
309 if (s2->pid == pid && s2->valid)
310 goto exists;
311 }
312 list_add(&s->list, &listeners->list);
313 s = NULL;
314exists:
315 up_write(&listeners->sem);
316 kfree(s); /* nop if NULL */
317 }
318 return 0;
319 }
320
321 /* Deregister or cleanup */
322cleanup:
323 for_each_cpu(cpu, mask) {
324 listeners = &per_cpu(listener_array, cpu);
325 down_write(&listeners->sem);
326 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
327 if (s->pid == pid) {
328 list_del(&s->list);
329 kfree(s);
330 break;
331 }
332 }
333 up_write(&listeners->sem);
334 }
335 return ret;
336}
337
338static int parse(struct nlattr *na, struct cpumask *mask)
339{
340 char *data;
341 int len;
342 int ret;
343
344 if (na == NULL)
345 return 1;
346 len = nla_len(na);
347 if (len > TASKSTATS_CPUMASK_MAXLEN)
348 return -E2BIG;
349 if (len < 1)
350 return -EINVAL;
351 data = kmalloc(len, GFP_KERNEL);
352 if (!data)
353 return -ENOMEM;
354 nla_strlcpy(data, na, len);
355 ret = cpulist_parse(data, mask);
356 kfree(data);
357 return ret;
358}
359
360#if defined(CONFIG_64BIT) && !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
361#define TASKSTATS_NEEDS_PADDING 1
362#endif
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 /*
374 * The taskstats structure is internally aligned on 8 byte
375 * boundaries but the layout of the aggregrate reply, with
376 * two NLA headers and the pid (each 4 bytes), actually
377 * force the entire structure to be unaligned. This causes
378 * the kernel to issue unaligned access warnings on some
379 * architectures like ia64. Unfortunately, some software out there
380 * doesn't properly unroll the NLA packet and assumes that the start
381 * of the taskstats structure will always be 20 bytes from the start
382 * of the netlink payload. Aligning the start of the taskstats
383 * structure breaks this software, which we don't want. So, for now
384 * the alignment only happens on architectures that require it
385 * and those users will have to update to fixed versions of those
386 * packages. Space is reserved in the packet only when needed.
387 * This ifdef should be removed in several years e.g. 2012 once
388 * we can be confident that fixed versions are installed on most
389 * systems. We add the padding before the aggregate since the
390 * aggregate is already a defined type.
391 */
392#ifdef TASKSTATS_NEEDS_PADDING
393 if (nla_put(skb, TASKSTATS_TYPE_NULL, 0, NULL) < 0)
394 goto err;
395#endif
396 na = nla_nest_start(skb, aggr);
397 if (!na)
398 goto err;
399
400 if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
401 nla_nest_cancel(skb, na);
402 goto err;
403 }
404 ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats));
405 if (!ret) {
406 nla_nest_cancel(skb, na);
407 goto err;
408 }
409 nla_nest_end(skb, na);
410
411 return nla_data(ret);
412err:
413 return NULL;
414}
415
416static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
417{
418 int rc = 0;
419 struct sk_buff *rep_skb;
420 struct cgroupstats *stats;
421 struct nlattr *na;
422 size_t size;
423 u32 fd;
424 struct fd f;
425
426 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
427 if (!na)
428 return -EINVAL;
429
430 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
431 f = fdget(fd);
432 if (!f.file)
433 return 0;
434
435 size = nla_total_size(sizeof(struct cgroupstats));
436
437 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
438 size);
439 if (rc < 0)
440 goto err;
441
442 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
443 sizeof(struct cgroupstats));
444 if (na == NULL) {
445 nlmsg_free(rep_skb);
446 rc = -EMSGSIZE;
447 goto err;
448 }
449
450 stats = nla_data(na);
451 memset(stats, 0, sizeof(*stats));
452
453 rc = cgroupstats_build(stats, f.file->f_path.dentry);
454 if (rc < 0) {
455 nlmsg_free(rep_skb);
456 goto err;
457 }
458
459 rc = send_reply(rep_skb, info);
460
461err:
462 fdput(f);
463 return rc;
464}
465
466static int cmd_attr_register_cpumask(struct genl_info *info)
467{
468 cpumask_var_t mask;
469 int rc;
470
471 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
472 return -ENOMEM;
473 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
474 if (rc < 0)
475 goto out;
476 rc = add_del_listener(info->snd_portid, mask, REGISTER);
477out:
478 free_cpumask_var(mask);
479 return rc;
480}
481
482static int cmd_attr_deregister_cpumask(struct genl_info *info)
483{
484 cpumask_var_t mask;
485 int rc;
486
487 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
488 return -ENOMEM;
489 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
490 if (rc < 0)
491 goto out;
492 rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
493out:
494 free_cpumask_var(mask);
495 return rc;
496}
497
498static size_t taskstats_packet_size(void)
499{
500 size_t size;
501
502 size = nla_total_size(sizeof(u32)) +
503 nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
504#ifdef TASKSTATS_NEEDS_PADDING
505 size += nla_total_size(0); /* Padding for alignment */
506#endif
507 return size;
508}
509
510static int cmd_attr_pid(struct genl_info *info)
511{
512 struct taskstats *stats;
513 struct sk_buff *rep_skb;
514 size_t size;
515 u32 pid;
516 int rc;
517
518 size = taskstats_packet_size();
519
520 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
521 if (rc < 0)
522 return rc;
523
524 rc = -EINVAL;
525 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
526 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
527 if (!stats)
528 goto err;
529
530 rc = fill_stats_for_pid(pid, stats);
531 if (rc < 0)
532 goto err;
533 return send_reply(rep_skb, info);
534err:
535 nlmsg_free(rep_skb);
536 return rc;
537}
538
539static int cmd_attr_tgid(struct genl_info *info)
540{
541 struct taskstats *stats;
542 struct sk_buff *rep_skb;
543 size_t size;
544 u32 tgid;
545 int rc;
546
547 size = taskstats_packet_size();
548
549 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
550 if (rc < 0)
551 return rc;
552
553 rc = -EINVAL;
554 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
555 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
556 if (!stats)
557 goto err;
558
559 rc = fill_stats_for_tgid(tgid, stats);
560 if (rc < 0)
561 goto err;
562 return send_reply(rep_skb, info);
563err:
564 nlmsg_free(rep_skb);
565 return rc;
566}
567
568static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
569{
570 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
571 return cmd_attr_register_cpumask(info);
572 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
573 return cmd_attr_deregister_cpumask(info);
574 else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
575 return cmd_attr_pid(info);
576 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
577 return cmd_attr_tgid(info);
578 else
579 return -EINVAL;
580}
581
582static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
583{
584 struct signal_struct *sig = tsk->signal;
585 struct taskstats *stats;
586
587 if (sig->stats || thread_group_empty(tsk))
588 goto ret;
589
590 /* No problem if kmem_cache_zalloc() fails */
591 stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
592
593 spin_lock_irq(&tsk->sighand->siglock);
594 if (!sig->stats) {
595 sig->stats = stats;
596 stats = NULL;
597 }
598 spin_unlock_irq(&tsk->sighand->siglock);
599
600 if (stats)
601 kmem_cache_free(taskstats_cache, stats);
602ret:
603 return sig->stats;
604}
605
606/* Send pid data out on exit */
607void taskstats_exit(struct task_struct *tsk, int group_dead)
608{
609 int rc;
610 struct listener_list *listeners;
611 struct taskstats *stats;
612 struct sk_buff *rep_skb;
613 size_t size;
614 int is_thread_group;
615
616 if (!family_registered)
617 return;
618
619 /*
620 * Size includes space for nested attributes
621 */
622 size = taskstats_packet_size();
623
624 is_thread_group = !!taskstats_tgid_alloc(tsk);
625 if (is_thread_group) {
626 /* PID + STATS + TGID + STATS */
627 size = 2 * size;
628 /* fill the tsk->signal->stats structure */
629 fill_tgid_exit(tsk);
630 }
631
632 listeners = raw_cpu_ptr(&listener_array);
633 if (list_empty(&listeners->list))
634 return;
635
636 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
637 if (rc < 0)
638 return;
639
640 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
641 task_pid_nr_ns(tsk, &init_pid_ns));
642 if (!stats)
643 goto err;
644
645 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
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 .doit = taskstats_user_cmd,
671 .policy = taskstats_cmd_get_policy,
672 .flags = GENL_ADMIN_PERM,
673 },
674 {
675 .cmd = CGROUPSTATS_CMD_GET,
676 .doit = cgroupstats_user_cmd,
677 .policy = cgroupstats_cmd_get_policy,
678 },
679};
680
681/* Needed early in initialization */
682void __init taskstats_init_early(void)
683{
684 unsigned int i;
685
686 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
687 for_each_possible_cpu(i) {
688 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
689 init_rwsem(&(per_cpu(listener_array, i).sem));
690 }
691}
692
693static int __init taskstats_init(void)
694{
695 int rc;
696
697 rc = genl_register_family_with_ops(&family, taskstats_ops);
698 if (rc)
699 return rc;
700
701 family_registered = 1;
702 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
703 return 0;
704}
705
706/*
707 * late initcall ensures initialization of statistics collection
708 * mechanisms precedes initialization of the taskstats interface
709 */
710late_initcall(taskstats_init);
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 start_time = ktime_get_ns();
237 for_each_thread(first, tsk) {
238 if (tsk->exit_state)
239 continue;
240 /*
241 * Accounting subsystem can call its functions here to
242 * fill in relevant parts of struct taskstsats as follows
243 *
244 * per-task-foo(stats, tsk);
245 */
246 delayacct_add_tsk(stats, tsk);
247
248 /* calculate task elapsed time in nsec */
249 delta = start_time - tsk->start_time;
250 /* Convert to micro seconds */
251 do_div(delta, NSEC_PER_USEC);
252 stats->ac_etime += delta;
253
254 task_cputime(tsk, &utime, &stime);
255 stats->ac_utime += div_u64(utime, NSEC_PER_USEC);
256 stats->ac_stime += div_u64(stime, NSEC_PER_USEC);
257
258 stats->nvcsw += tsk->nvcsw;
259 stats->nivcsw += tsk->nivcsw;
260 }
261
262 unlock_task_sighand(first, &flags);
263 rc = 0;
264out:
265 rcu_read_unlock();
266
267 stats->version = TASKSTATS_VERSION;
268 /*
269 * Accounting subsystems can also add calls here to modify
270 * fields of taskstats.
271 */
272 return rc;
273}
274
275static void fill_tgid_exit(struct task_struct *tsk)
276{
277 unsigned long flags;
278
279 spin_lock_irqsave(&tsk->sighand->siglock, flags);
280 if (!tsk->signal->stats)
281 goto ret;
282
283 /*
284 * Each accounting subsystem calls its functions here to
285 * accumalate its per-task stats for tsk, into the per-tgid structure
286 *
287 * per-task-foo(tsk->signal->stats, tsk);
288 */
289 delayacct_add_tsk(tsk->signal->stats, tsk);
290ret:
291 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
292 return;
293}
294
295static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
296{
297 struct listener_list *listeners;
298 struct listener *s, *tmp, *s2;
299 unsigned int cpu;
300 int ret = 0;
301
302 if (!cpumask_subset(mask, cpu_possible_mask))
303 return -EINVAL;
304
305 if (current_user_ns() != &init_user_ns)
306 return -EINVAL;
307
308 if (task_active_pid_ns(current) != &init_pid_ns)
309 return -EINVAL;
310
311 if (isadd == REGISTER) {
312 for_each_cpu(cpu, mask) {
313 s = kmalloc_node(sizeof(struct listener),
314 GFP_KERNEL, cpu_to_node(cpu));
315 if (!s) {
316 ret = -ENOMEM;
317 goto cleanup;
318 }
319 s->pid = pid;
320 s->valid = 1;
321
322 listeners = &per_cpu(listener_array, cpu);
323 down_write(&listeners->sem);
324 list_for_each_entry(s2, &listeners->list, list) {
325 if (s2->pid == pid && s2->valid)
326 goto exists;
327 }
328 list_add(&s->list, &listeners->list);
329 s = NULL;
330exists:
331 up_write(&listeners->sem);
332 kfree(s); /* nop if NULL */
333 }
334 return 0;
335 }
336
337 /* Deregister or cleanup */
338cleanup:
339 for_each_cpu(cpu, mask) {
340 listeners = &per_cpu(listener_array, cpu);
341 down_write(&listeners->sem);
342 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
343 if (s->pid == pid) {
344 list_del(&s->list);
345 kfree(s);
346 break;
347 }
348 }
349 up_write(&listeners->sem);
350 }
351 return ret;
352}
353
354static int parse(struct nlattr *na, struct cpumask *mask)
355{
356 char *data;
357 int len;
358 int ret;
359
360 if (na == NULL)
361 return 1;
362 len = nla_len(na);
363 if (len > TASKSTATS_CPUMASK_MAXLEN)
364 return -E2BIG;
365 if (len < 1)
366 return -EINVAL;
367 data = kmalloc(len, GFP_KERNEL);
368 if (!data)
369 return -ENOMEM;
370 nla_strscpy(data, na, len);
371 ret = cpulist_parse(data, mask);
372 kfree(data);
373 return ret;
374}
375
376static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
377{
378 struct nlattr *na, *ret;
379 int aggr;
380
381 aggr = (type == TASKSTATS_TYPE_PID)
382 ? TASKSTATS_TYPE_AGGR_PID
383 : TASKSTATS_TYPE_AGGR_TGID;
384
385 na = nla_nest_start_noflag(skb, aggr);
386 if (!na)
387 goto err;
388
389 if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
390 nla_nest_cancel(skb, na);
391 goto err;
392 }
393 ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
394 sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
395 if (!ret) {
396 nla_nest_cancel(skb, na);
397 goto err;
398 }
399 nla_nest_end(skb, na);
400
401 return nla_data(ret);
402err:
403 return NULL;
404}
405
406static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
407{
408 int rc = 0;
409 struct sk_buff *rep_skb;
410 struct cgroupstats *stats;
411 struct nlattr *na;
412 size_t size;
413 u32 fd;
414
415 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
416 if (!na)
417 return -EINVAL;
418
419 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
420 CLASS(fd, f)(fd);
421 if (fd_empty(f))
422 return 0;
423
424 size = nla_total_size(sizeof(struct cgroupstats));
425
426 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
427 size);
428 if (rc < 0)
429 return rc;
430
431 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
432 sizeof(struct cgroupstats));
433 if (na == NULL) {
434 nlmsg_free(rep_skb);
435 return -EMSGSIZE;
436 }
437
438 stats = nla_data(na);
439 memset(stats, 0, sizeof(*stats));
440
441 rc = cgroupstats_build(stats, fd_file(f)->f_path.dentry);
442 if (rc < 0) {
443 nlmsg_free(rep_skb);
444 return rc;
445 }
446
447 return send_reply(rep_skb, info);
448}
449
450static int cmd_attr_register_cpumask(struct genl_info *info)
451{
452 cpumask_var_t mask;
453 int rc;
454
455 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
456 return -ENOMEM;
457 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
458 if (rc < 0)
459 goto out;
460 rc = add_del_listener(info->snd_portid, mask, REGISTER);
461out:
462 free_cpumask_var(mask);
463 return rc;
464}
465
466static int cmd_attr_deregister_cpumask(struct genl_info *info)
467{
468 cpumask_var_t mask;
469 int rc;
470
471 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
472 return -ENOMEM;
473 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
474 if (rc < 0)
475 goto out;
476 rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
477out:
478 free_cpumask_var(mask);
479 return rc;
480}
481
482static size_t taskstats_packet_size(void)
483{
484 size_t size;
485
486 size = nla_total_size(sizeof(u32)) +
487 nla_total_size_64bit(sizeof(struct taskstats)) +
488 nla_total_size(0);
489
490 return size;
491}
492
493static int cmd_attr_pid(struct genl_info *info)
494{
495 struct taskstats *stats;
496 struct sk_buff *rep_skb;
497 size_t size;
498 u32 pid;
499 int rc;
500
501 size = taskstats_packet_size();
502
503 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
504 if (rc < 0)
505 return rc;
506
507 rc = -EINVAL;
508 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
509 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
510 if (!stats)
511 goto err;
512
513 rc = fill_stats_for_pid(pid, stats);
514 if (rc < 0)
515 goto err;
516 return send_reply(rep_skb, info);
517err:
518 nlmsg_free(rep_skb);
519 return rc;
520}
521
522static int cmd_attr_tgid(struct genl_info *info)
523{
524 struct taskstats *stats;
525 struct sk_buff *rep_skb;
526 size_t size;
527 u32 tgid;
528 int rc;
529
530 size = taskstats_packet_size();
531
532 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
533 if (rc < 0)
534 return rc;
535
536 rc = -EINVAL;
537 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
538 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
539 if (!stats)
540 goto err;
541
542 rc = fill_stats_for_tgid(tgid, stats);
543 if (rc < 0)
544 goto err;
545 return send_reply(rep_skb, info);
546err:
547 nlmsg_free(rep_skb);
548 return rc;
549}
550
551static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
552{
553 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
554 return cmd_attr_register_cpumask(info);
555 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
556 return cmd_attr_deregister_cpumask(info);
557 else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
558 return cmd_attr_pid(info);
559 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
560 return cmd_attr_tgid(info);
561 else
562 return -EINVAL;
563}
564
565static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
566{
567 struct signal_struct *sig = tsk->signal;
568 struct taskstats *stats_new, *stats;
569
570 /* Pairs with smp_store_release() below. */
571 stats = smp_load_acquire(&sig->stats);
572 if (stats || thread_group_empty(tsk))
573 return stats;
574
575 /* No problem if kmem_cache_zalloc() fails */
576 stats_new = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
577
578 spin_lock_irq(&tsk->sighand->siglock);
579 stats = sig->stats;
580 if (!stats) {
581 /*
582 * Pairs with smp_store_release() above and order the
583 * kmem_cache_zalloc().
584 */
585 smp_store_release(&sig->stats, stats_new);
586 stats = stats_new;
587 stats_new = NULL;
588 }
589 spin_unlock_irq(&tsk->sighand->siglock);
590
591 if (stats_new)
592 kmem_cache_free(taskstats_cache, stats_new);
593
594 return stats;
595}
596
597/* Send pid data out on exit */
598void taskstats_exit(struct task_struct *tsk, int group_dead)
599{
600 int rc;
601 struct listener_list *listeners;
602 struct taskstats *stats;
603 struct sk_buff *rep_skb;
604 size_t size;
605 int is_thread_group;
606
607 if (!family_registered)
608 return;
609
610 /*
611 * Size includes space for nested attributes
612 */
613 size = taskstats_packet_size();
614
615 is_thread_group = !!taskstats_tgid_alloc(tsk);
616 if (is_thread_group) {
617 /* PID + STATS + TGID + STATS */
618 size = 2 * size;
619 /* fill the tsk->signal->stats structure */
620 fill_tgid_exit(tsk);
621 }
622
623 listeners = raw_cpu_ptr(&listener_array);
624 if (list_empty(&listeners->list))
625 return;
626
627 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
628 if (rc < 0)
629 return;
630
631 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
632 task_pid_nr_ns(tsk, &init_pid_ns));
633 if (!stats)
634 goto err;
635
636 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
637 if (group_dead)
638 stats->ac_flag |= AGROUP;
639
640 /*
641 * Doesn't matter if tsk is the leader or the last group member leaving
642 */
643 if (!is_thread_group || !group_dead)
644 goto send;
645
646 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
647 task_tgid_nr_ns(tsk, &init_pid_ns));
648 if (!stats)
649 goto err;
650
651 memcpy(stats, tsk->signal->stats, sizeof(*stats));
652
653send:
654 send_cpu_listeners(rep_skb, listeners);
655 return;
656err:
657 nlmsg_free(rep_skb);
658}
659
660static const struct genl_ops taskstats_ops[] = {
661 {
662 .cmd = TASKSTATS_CMD_GET,
663 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
664 .doit = taskstats_user_cmd,
665 .policy = taskstats_cmd_get_policy,
666 .maxattr = ARRAY_SIZE(taskstats_cmd_get_policy) - 1,
667 .flags = GENL_ADMIN_PERM,
668 },
669 {
670 .cmd = CGROUPSTATS_CMD_GET,
671 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
672 .doit = cgroupstats_user_cmd,
673 .policy = cgroupstats_cmd_get_policy,
674 .maxattr = ARRAY_SIZE(cgroupstats_cmd_get_policy) - 1,
675 },
676};
677
678static struct genl_family family __ro_after_init = {
679 .name = TASKSTATS_GENL_NAME,
680 .version = TASKSTATS_GENL_VERSION,
681 .module = THIS_MODULE,
682 .ops = taskstats_ops,
683 .n_ops = ARRAY_SIZE(taskstats_ops),
684 .resv_start_op = CGROUPSTATS_CMD_GET + 1,
685 .netnsok = true,
686};
687
688/* Needed early in initialization */
689void __init taskstats_init_early(void)
690{
691 unsigned int i;
692
693 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
694 for_each_possible_cpu(i) {
695 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
696 init_rwsem(&(per_cpu(listener_array, i).sem));
697 }
698}
699
700static int __init taskstats_init(void)
701{
702 int rc;
703
704 rc = genl_register_family(&family);
705 if (rc)
706 return rc;
707
708 family_registered = 1;
709 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
710 return 0;
711}
712
713/*
714 * late initcall ensures initialization of statistics collection
715 * mechanisms precedes initialization of the taskstats interface
716 */
717late_initcall(taskstats_init);