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/delayacct.h> 13 #include <linux/cpumask.h> 14 #include <linux/percpu.h> 15 #include <linux/slab.h> 16 #include <linux/cgroupstats.h> 17 #include <linux/cgroup.h> 18 #include <linux/fs.h> 19 #include <linux/file.h> 20 #include <linux/pid_namespace.h> 21 #include <net/genetlink.h> 22 #include <linux/atomic.h> 23 #include <linux/sched/cputime.h> 24 25 /* 26 * Maximum length of a cpumask that can be specified in 27 * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute 28 */ 29 #define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS) 30 31 static DEFINE_PER_CPU(__u32, taskstats_seqnum); 32 static int family_registered; 33 struct kmem_cache *taskstats_cache; 34 35 static struct genl_family family; 36 37 static const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = { 38 [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 }, 39 [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 }, 40 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING }, 41 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },}; 42 43 /* 44 * We have to use TASKSTATS_CMD_ATTR_MAX here, it is the maxattr in the family. 45 * Make sure they are always aligned. 46 */ 47 static const struct nla_policy cgroupstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = { 48 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 }, 49 }; 50 51 struct listener { 52 struct list_head list; 53 pid_t pid; 54 char valid; 55 }; 56 57 struct listener_list { 58 struct rw_semaphore sem; 59 struct list_head list; 60 }; 61 static DEFINE_PER_CPU(struct listener_list, listener_array); 62 63 enum actions { 64 REGISTER, 65 DEREGISTER, 66 CPU_DONT_CARE 67 }; 68 69 static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp, 70 size_t size) 71 { 72 struct sk_buff *skb; 73 void *reply; 74 75 /* 76 * If new attributes are added, please revisit this allocation 77 */ 78 skb = genlmsg_new(size, GFP_KERNEL); 79 if (!skb) 80 return -ENOMEM; 81 82 if (!info) { 83 int seq = this_cpu_inc_return(taskstats_seqnum) - 1; 84 85 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd); 86 } else 87 reply = genlmsg_put_reply(skb, info, &family, 0, cmd); 88 if (reply == NULL) { 89 nlmsg_free(skb); 90 return -EINVAL; 91 } 92 93 *skbp = skb; 94 return 0; 95 } 96 97 /* 98 * Send taskstats data in @skb to listener with nl_pid @pid 99 */ 100 static int send_reply(struct sk_buff *skb, struct genl_info *info) 101 { 102 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb)); 103 void *reply = genlmsg_data(genlhdr); 104 105 genlmsg_end(skb, reply); 106 107 return genlmsg_reply(skb, info); 108 } 109 110 /* 111 * Send taskstats data in @skb to listeners registered for @cpu's exit data 112 */ 113 static void send_cpu_listeners(struct sk_buff *skb, 114 struct listener_list *listeners) 115 { 116 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb)); 117 struct listener *s, *tmp; 118 struct sk_buff *skb_next, *skb_cur = skb; 119 void *reply = genlmsg_data(genlhdr); 120 int rc, delcount = 0; 121 122 genlmsg_end(skb, reply); 123 124 rc = 0; 125 down_read(&listeners->sem); 126 list_for_each_entry(s, &listeners->list, list) { 127 skb_next = NULL; 128 if (!list_is_last(&s->list, &listeners->list)) { 129 skb_next = skb_clone(skb_cur, GFP_KERNEL); 130 if (!skb_next) 131 break; 132 } 133 rc = genlmsg_unicast(&init_net, skb_cur, s->pid); 134 if (rc == -ECONNREFUSED) { 135 s->valid = 0; 136 delcount++; 137 } 138 skb_cur = skb_next; 139 } 140 up_read(&listeners->sem); 141 142 if (skb_cur) 143 nlmsg_free(skb_cur); 144 145 if (!delcount) 146 return; 147 148 /* Delete invalidated entries */ 149 down_write(&listeners->sem); 150 list_for_each_entry_safe(s, tmp, &listeners->list, list) { 151 if (!s->valid) { 152 list_del(&s->list); 153 kfree(s); 154 } 155 } 156 up_write(&listeners->sem); 157 } 158 159 static void fill_stats(struct user_namespace *user_ns, 160 struct pid_namespace *pid_ns, 161 struct task_struct *tsk, struct taskstats *stats) 162 { 163 memset(stats, 0, sizeof(*stats)); 164 /* 165 * Each accounting subsystem adds calls to its functions to 166 * fill in relevant parts of struct taskstsats as follows 167 * 168 * per-task-foo(stats, tsk); 169 */ 170 171 delayacct_add_tsk(stats, tsk); 172 173 /* fill in basic acct fields */ 174 stats->version = TASKSTATS_VERSION; 175 stats->nvcsw = tsk->nvcsw; 176 stats->nivcsw = tsk->nivcsw; 177 bacct_add_tsk(user_ns, pid_ns, stats, tsk); 178 179 /* fill in extended acct fields */ 180 xacct_add_tsk(stats, tsk); 181 } 182 183 static int fill_stats_for_pid(pid_t pid, struct taskstats *stats) 184 { 185 struct task_struct *tsk; 186 187 tsk = find_get_task_by_vpid(pid); 188 if (!tsk) 189 return -ESRCH; 190 fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats); 191 put_task_struct(tsk); 192 return 0; 193 } 194 195 static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats) 196 { 197 struct task_struct *tsk, *first; 198 unsigned long flags; 199 int rc = -ESRCH; 200 u64 delta, utime, stime; 201 u64 start_time; 202 203 /* 204 * Add additional stats from live tasks except zombie thread group 205 * leaders who are already counted with the dead tasks 206 */ 207 rcu_read_lock(); 208 first = find_task_by_vpid(tgid); 209 210 if (!first || !lock_task_sighand(first, &flags)) 211 goto out; 212 213 if (first->signal->stats) 214 memcpy(stats, first->signal->stats, sizeof(*stats)); 215 else 216 memset(stats, 0, sizeof(*stats)); 217 218 tsk = first; 219 start_time = ktime_get_ns(); 220 do { 221 if (tsk->exit_state) 222 continue; 223 /* 224 * Accounting subsystem can call its functions here to 225 * fill in relevant parts of struct taskstsats as follows 226 * 227 * per-task-foo(stats, tsk); 228 */ 229 delayacct_add_tsk(stats, tsk); 230 231 /* calculate task elapsed time in nsec */ 232 delta = start_time - tsk->start_time; 233 /* Convert to micro seconds */ 234 do_div(delta, NSEC_PER_USEC); 235 stats->ac_etime += delta; 236 237 task_cputime(tsk, &utime, &stime); 238 stats->ac_utime += div_u64(utime, NSEC_PER_USEC); 239 stats->ac_stime += div_u64(stime, NSEC_PER_USEC); 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; 247 out: 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 } 257 258 static 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); 273 ret: 274 spin_unlock_irqrestore(&tsk->sighand->siglock, flags); 275 return; 276 } 277 278 static 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; 313 exists: 314 up_write(&listeners->sem); 315 kfree(s); /* nop if NULL */ 316 } 317 return 0; 318 } 319 320 /* Deregister or cleanup */ 321 cleanup: 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 } 336 337 static 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 } 358 359 static 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_noflag(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); 385 err: 386 return NULL; 387 } 388 389 static 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); 433 434 err: 435 fdput(f); 436 return rc; 437 } 438 439 static 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); 450 out: 451 free_cpumask_var(mask); 452 return rc; 453 } 454 455 static 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); 466 out: 467 free_cpumask_var(mask); 468 return rc; 469 } 470 471 static 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 } 481 482 static 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); 506 err: 507 nlmsg_free(rep_skb); 508 return rc; 509 } 510 511 static 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); 535 err: 536 nlmsg_free(rep_skb); 537 return rc; 538 } 539 540 static 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 } 553 554 static 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); 574 ret: 575 return sig->stats; 576 } 577 578 /* Send pid data out on exit */ 579 void 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)); 631 632 send: 633 send_cpu_listeners(rep_skb, listeners); 634 return; 635 err: 636 nlmsg_free(rep_skb); 637 } 638 639 static const struct genl_ops taskstats_ops[] = { 640 { 641 .cmd = TASKSTATS_CMD_GET, 642 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 643 .doit = taskstats_user_cmd, 644 /* policy enforced later */ 645 .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_HASPOL, 646 }, 647 { 648 .cmd = CGROUPSTATS_CMD_GET, 649 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 650 .doit = cgroupstats_user_cmd, 651 /* policy enforced later */ 652 .flags = GENL_CMD_CAP_HASPOL, 653 }, 654 }; 655 656 static int taskstats_pre_doit(const struct genl_ops *ops, struct sk_buff *skb, 657 struct genl_info *info) 658 { 659 const struct nla_policy *policy = NULL; 660 661 switch (ops->cmd) { 662 case TASKSTATS_CMD_GET: 663 policy = taskstats_cmd_get_policy; 664 break; 665 case CGROUPSTATS_CMD_GET: 666 policy = cgroupstats_cmd_get_policy; 667 break; 668 default: 669 return -EINVAL; 670 } 671 672 return nlmsg_validate_deprecated(info->nlhdr, GENL_HDRLEN, 673 TASKSTATS_CMD_ATTR_MAX, policy, 674 info->extack); 675 } 676 677 static struct genl_family family __ro_after_init = { 678 .name = TASKSTATS_GENL_NAME, 679 .version = TASKSTATS_GENL_VERSION, 680 .maxattr = TASKSTATS_CMD_ATTR_MAX, 681 .module = THIS_MODULE, 682 .ops = taskstats_ops, 683 .n_ops = ARRAY_SIZE(taskstats_ops), 684 .pre_doit = taskstats_pre_doit, 685 }; 686 687 /* Needed early in initialization */ 688 void __init taskstats_init_early(void) 689 { 690 unsigned int i; 691 692 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC); 693 for_each_possible_cpu(i) { 694 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list)); 695 init_rwsem(&(per_cpu(listener_array, i).sem)); 696 } 697 } 698 699 static int __init taskstats_init(void) 700 { 701 int rc; 702 703 rc = genl_register_family(&family); 704 if (rc) 705 return rc; 706 707 family_registered = 1; 708 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION); 709 return 0; 710 } 711 712 /* 713 * late initcall ensures initialization of statistics collection 714 * mechanisms precedes initialization of the taskstats interface 715 */ 716 late_initcall(taskstats_init); 717