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 32 static DEFINE_PER_CPU(__u32, taskstats_seqnum); 33 static int family_registered; 34 struct kmem_cache *taskstats_cache; 35 36 static struct genl_family family; 37 38 static 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 44 static const struct nla_policy cgroupstats_cmd_get_policy[] = { 45 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 }, 46 }; 47 48 struct listener { 49 struct list_head list; 50 pid_t pid; 51 char valid; 52 }; 53 54 struct listener_list { 55 struct rw_semaphore sem; 56 struct list_head list; 57 }; 58 static DEFINE_PER_CPU(struct listener_list, listener_array); 59 60 enum actions { 61 REGISTER, 62 DEREGISTER, 63 CPU_DONT_CARE 64 }; 65 66 static 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 */ 97 static 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 */ 110 static 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 } 156 157 static 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 } 173 174 static 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 } 200 201 static 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 } 212 213 static 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; 264 out: 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 } 274 275 static 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); 290 ret: 291 spin_unlock_irqrestore(&tsk->sighand->siglock, flags); 292 return; 293 } 294 295 static 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; 330 exists: 331 up_write(&listeners->sem); 332 kfree(s); /* nop if NULL */ 333 } 334 return 0; 335 } 336 337 /* Deregister or cleanup */ 338 cleanup: 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 } 353 354 static 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 } 375 376 static 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); 402 err: 403 return NULL; 404 } 405 406 static 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 struct fd f; 415 416 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD]; 417 if (!na) 418 return -EINVAL; 419 420 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]); 421 f = fdget(fd); 422 if (!f.file) 423 return 0; 424 425 size = nla_total_size(sizeof(struct cgroupstats)); 426 427 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb, 428 size); 429 if (rc < 0) 430 goto err; 431 432 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS, 433 sizeof(struct cgroupstats)); 434 if (na == NULL) { 435 nlmsg_free(rep_skb); 436 rc = -EMSGSIZE; 437 goto err; 438 } 439 440 stats = nla_data(na); 441 memset(stats, 0, sizeof(*stats)); 442 443 rc = cgroupstats_build(stats, f.file->f_path.dentry); 444 if (rc < 0) { 445 nlmsg_free(rep_skb); 446 goto err; 447 } 448 449 rc = send_reply(rep_skb, info); 450 451 err: 452 fdput(f); 453 return rc; 454 } 455 456 static int cmd_attr_register_cpumask(struct genl_info *info) 457 { 458 cpumask_var_t mask; 459 int rc; 460 461 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 462 return -ENOMEM; 463 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask); 464 if (rc < 0) 465 goto out; 466 rc = add_del_listener(info->snd_portid, mask, REGISTER); 467 out: 468 free_cpumask_var(mask); 469 return rc; 470 } 471 472 static int cmd_attr_deregister_cpumask(struct genl_info *info) 473 { 474 cpumask_var_t mask; 475 int rc; 476 477 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 478 return -ENOMEM; 479 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask); 480 if (rc < 0) 481 goto out; 482 rc = add_del_listener(info->snd_portid, mask, DEREGISTER); 483 out: 484 free_cpumask_var(mask); 485 return rc; 486 } 487 488 static size_t taskstats_packet_size(void) 489 { 490 size_t size; 491 492 size = nla_total_size(sizeof(u32)) + 493 nla_total_size_64bit(sizeof(struct taskstats)) + 494 nla_total_size(0); 495 496 return size; 497 } 498 499 static int cmd_attr_pid(struct genl_info *info) 500 { 501 struct taskstats *stats; 502 struct sk_buff *rep_skb; 503 size_t size; 504 u32 pid; 505 int rc; 506 507 size = taskstats_packet_size(); 508 509 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); 510 if (rc < 0) 511 return rc; 512 513 rc = -EINVAL; 514 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]); 515 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid); 516 if (!stats) 517 goto err; 518 519 rc = fill_stats_for_pid(pid, stats); 520 if (rc < 0) 521 goto err; 522 return send_reply(rep_skb, info); 523 err: 524 nlmsg_free(rep_skb); 525 return rc; 526 } 527 528 static int cmd_attr_tgid(struct genl_info *info) 529 { 530 struct taskstats *stats; 531 struct sk_buff *rep_skb; 532 size_t size; 533 u32 tgid; 534 int rc; 535 536 size = taskstats_packet_size(); 537 538 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); 539 if (rc < 0) 540 return rc; 541 542 rc = -EINVAL; 543 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]); 544 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid); 545 if (!stats) 546 goto err; 547 548 rc = fill_stats_for_tgid(tgid, stats); 549 if (rc < 0) 550 goto err; 551 return send_reply(rep_skb, info); 552 err: 553 nlmsg_free(rep_skb); 554 return rc; 555 } 556 557 static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info) 558 { 559 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK]) 560 return cmd_attr_register_cpumask(info); 561 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK]) 562 return cmd_attr_deregister_cpumask(info); 563 else if (info->attrs[TASKSTATS_CMD_ATTR_PID]) 564 return cmd_attr_pid(info); 565 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) 566 return cmd_attr_tgid(info); 567 else 568 return -EINVAL; 569 } 570 571 static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk) 572 { 573 struct signal_struct *sig = tsk->signal; 574 struct taskstats *stats_new, *stats; 575 576 /* Pairs with smp_store_release() below. */ 577 stats = smp_load_acquire(&sig->stats); 578 if (stats || thread_group_empty(tsk)) 579 return stats; 580 581 /* No problem if kmem_cache_zalloc() fails */ 582 stats_new = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL); 583 584 spin_lock_irq(&tsk->sighand->siglock); 585 stats = sig->stats; 586 if (!stats) { 587 /* 588 * Pairs with smp_store_release() above and order the 589 * kmem_cache_zalloc(). 590 */ 591 smp_store_release(&sig->stats, stats_new); 592 stats = stats_new; 593 stats_new = NULL; 594 } 595 spin_unlock_irq(&tsk->sighand->siglock); 596 597 if (stats_new) 598 kmem_cache_free(taskstats_cache, stats_new); 599 600 return stats; 601 } 602 603 /* Send pid data out on exit */ 604 void taskstats_exit(struct task_struct *tsk, int group_dead) 605 { 606 int rc; 607 struct listener_list *listeners; 608 struct taskstats *stats; 609 struct sk_buff *rep_skb; 610 size_t size; 611 int is_thread_group; 612 613 if (!family_registered) 614 return; 615 616 /* 617 * Size includes space for nested attributes 618 */ 619 size = taskstats_packet_size(); 620 621 is_thread_group = !!taskstats_tgid_alloc(tsk); 622 if (is_thread_group) { 623 /* PID + STATS + TGID + STATS */ 624 size = 2 * size; 625 /* fill the tsk->signal->stats structure */ 626 fill_tgid_exit(tsk); 627 } 628 629 listeners = raw_cpu_ptr(&listener_array); 630 if (list_empty(&listeners->list)) 631 return; 632 633 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size); 634 if (rc < 0) 635 return; 636 637 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, 638 task_pid_nr_ns(tsk, &init_pid_ns)); 639 if (!stats) 640 goto err; 641 642 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats); 643 if (group_dead) 644 stats->ac_flag |= AGROUP; 645 646 /* 647 * Doesn't matter if tsk is the leader or the last group member leaving 648 */ 649 if (!is_thread_group || !group_dead) 650 goto send; 651 652 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, 653 task_tgid_nr_ns(tsk, &init_pid_ns)); 654 if (!stats) 655 goto err; 656 657 memcpy(stats, tsk->signal->stats, sizeof(*stats)); 658 659 send: 660 send_cpu_listeners(rep_skb, listeners); 661 return; 662 err: 663 nlmsg_free(rep_skb); 664 } 665 666 static const struct genl_ops taskstats_ops[] = { 667 { 668 .cmd = TASKSTATS_CMD_GET, 669 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 670 .doit = taskstats_user_cmd, 671 .policy = taskstats_cmd_get_policy, 672 .maxattr = ARRAY_SIZE(taskstats_cmd_get_policy) - 1, 673 .flags = GENL_ADMIN_PERM, 674 }, 675 { 676 .cmd = CGROUPSTATS_CMD_GET, 677 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 678 .doit = cgroupstats_user_cmd, 679 .policy = cgroupstats_cmd_get_policy, 680 .maxattr = ARRAY_SIZE(cgroupstats_cmd_get_policy) - 1, 681 }, 682 }; 683 684 static struct genl_family family __ro_after_init = { 685 .name = TASKSTATS_GENL_NAME, 686 .version = TASKSTATS_GENL_VERSION, 687 .module = THIS_MODULE, 688 .ops = taskstats_ops, 689 .n_ops = ARRAY_SIZE(taskstats_ops), 690 .resv_start_op = CGROUPSTATS_CMD_GET + 1, 691 .netnsok = true, 692 }; 693 694 /* Needed early in initialization */ 695 void __init taskstats_init_early(void) 696 { 697 unsigned int i; 698 699 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC); 700 for_each_possible_cpu(i) { 701 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list)); 702 init_rwsem(&(per_cpu(listener_array, i).sem)); 703 } 704 } 705 706 static int __init taskstats_init(void) 707 { 708 int rc; 709 710 rc = genl_register_family(&family); 711 if (rc) 712 return rc; 713 714 family_registered = 1; 715 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION); 716 return 0; 717 } 718 719 /* 720 * late initcall ensures initialization of statistics collection 721 * mechanisms precedes initialization of the taskstats interface 722 */ 723 late_initcall(taskstats_init); 724