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 40 static DEFINE_PER_CPU(__u32, taskstats_seqnum); 41 static int family_registered; 42 struct kmem_cache *taskstats_cache; 43 44 static struct genl_family family; 45 46 static 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 */ 56 static const struct nla_policy cgroupstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = { 57 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 }, 58 }; 59 60 struct listener { 61 struct list_head list; 62 pid_t pid; 63 char valid; 64 }; 65 66 struct listener_list { 67 struct rw_semaphore sem; 68 struct list_head list; 69 }; 70 static DEFINE_PER_CPU(struct listener_list, listener_array); 71 72 enum actions { 73 REGISTER, 74 DEREGISTER, 75 CPU_DONT_CARE 76 }; 77 78 static 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 */ 109 static 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 */ 122 static 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 } 167 168 static 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 } 191 192 static 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 } 207 208 static 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; 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(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 .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 }; 652 653 static 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 */ 663 void __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 } 673 674 static 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 */ 691 late_initcall(taskstats_init); 692