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 .id = GENL_ID_GENERATE, 46 .name = TASKSTATS_GENL_NAME, 47 .version = TASKSTATS_GENL_VERSION, 48 .maxattr = TASKSTATS_CMD_ATTR_MAX, 49 }; 50 51 static 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 57 static const struct nla_policy cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] = { 58 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 }, 59 }; 60 61 struct listener { 62 struct list_head list; 63 pid_t pid; 64 char valid; 65 }; 66 67 struct listener_list { 68 struct rw_semaphore sem; 69 struct list_head list; 70 }; 71 static DEFINE_PER_CPU(struct listener_list, listener_array); 72 73 enum actions { 74 REGISTER, 75 DEREGISTER, 76 CPU_DONT_CARE 77 }; 78 79 static 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 */ 110 static 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 */ 123 static 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 } 168 169 static 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 } 192 193 static 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 } 208 209 static 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; 248 out: 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 } 258 259 static 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); 274 ret: 275 spin_unlock_irqrestore(&tsk->sighand->siglock, flags); 276 return; 277 } 278 279 static 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; 314 exists: 315 up_write(&listeners->sem); 316 kfree(s); /* nop if NULL */ 317 } 318 return 0; 319 } 320 321 /* Deregister or cleanup */ 322 cleanup: 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 } 337 338 static 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 363 364 static 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); 412 err: 413 return NULL; 414 } 415 416 static 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); 460 461 err: 462 fdput(f); 463 return rc; 464 } 465 466 static 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); 477 out: 478 free_cpumask_var(mask); 479 return rc; 480 } 481 482 static 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); 493 out: 494 free_cpumask_var(mask); 495 return rc; 496 } 497 498 static 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 } 509 510 static 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); 534 err: 535 nlmsg_free(rep_skb); 536 return rc; 537 } 538 539 static 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); 563 err: 564 nlmsg_free(rep_skb); 565 return rc; 566 } 567 568 static 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 } 581 582 static 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); 602 ret: 603 return sig->stats; 604 } 605 606 /* Send pid data out on exit */ 607 void 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)); 659 660 send: 661 send_cpu_listeners(rep_skb, listeners); 662 return; 663 err: 664 nlmsg_free(rep_skb); 665 } 666 667 static 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 */ 682 void __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 } 692 693 static 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 */ 710 late_initcall(taskstats_init); 711