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 int rc; 115 116 rc = genlmsg_end(skb, reply); 117 if (rc < 0) { 118 nlmsg_free(skb); 119 return rc; 120 } 121 122 return genlmsg_reply(skb, info); 123 } 124 125 /* 126 * Send taskstats data in @skb to listeners registered for @cpu's exit data 127 */ 128 static void send_cpu_listeners(struct sk_buff *skb, 129 struct listener_list *listeners) 130 { 131 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb)); 132 struct listener *s, *tmp; 133 struct sk_buff *skb_next, *skb_cur = skb; 134 void *reply = genlmsg_data(genlhdr); 135 int rc, delcount = 0; 136 137 rc = genlmsg_end(skb, reply); 138 if (rc < 0) { 139 nlmsg_free(skb); 140 return; 141 } 142 143 rc = 0; 144 down_read(&listeners->sem); 145 list_for_each_entry(s, &listeners->list, list) { 146 skb_next = NULL; 147 if (!list_is_last(&s->list, &listeners->list)) { 148 skb_next = skb_clone(skb_cur, GFP_KERNEL); 149 if (!skb_next) 150 break; 151 } 152 rc = genlmsg_unicast(&init_net, skb_cur, s->pid); 153 if (rc == -ECONNREFUSED) { 154 s->valid = 0; 155 delcount++; 156 } 157 skb_cur = skb_next; 158 } 159 up_read(&listeners->sem); 160 161 if (skb_cur) 162 nlmsg_free(skb_cur); 163 164 if (!delcount) 165 return; 166 167 /* Delete invalidated entries */ 168 down_write(&listeners->sem); 169 list_for_each_entry_safe(s, tmp, &listeners->list, list) { 170 if (!s->valid) { 171 list_del(&s->list); 172 kfree(s); 173 } 174 } 175 up_write(&listeners->sem); 176 } 177 178 static void fill_stats(struct user_namespace *user_ns, 179 struct pid_namespace *pid_ns, 180 struct task_struct *tsk, struct taskstats *stats) 181 { 182 memset(stats, 0, sizeof(*stats)); 183 /* 184 * Each accounting subsystem adds calls to its functions to 185 * fill in relevant parts of struct taskstsats as follows 186 * 187 * per-task-foo(stats, tsk); 188 */ 189 190 delayacct_add_tsk(stats, tsk); 191 192 /* fill in basic acct fields */ 193 stats->version = TASKSTATS_VERSION; 194 stats->nvcsw = tsk->nvcsw; 195 stats->nivcsw = tsk->nivcsw; 196 bacct_add_tsk(user_ns, pid_ns, stats, tsk); 197 198 /* fill in extended acct fields */ 199 xacct_add_tsk(stats, tsk); 200 } 201 202 static int fill_stats_for_pid(pid_t pid, struct taskstats *stats) 203 { 204 struct task_struct *tsk; 205 206 rcu_read_lock(); 207 tsk = find_task_by_vpid(pid); 208 if (tsk) 209 get_task_struct(tsk); 210 rcu_read_unlock(); 211 if (!tsk) 212 return -ESRCH; 213 fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats); 214 put_task_struct(tsk); 215 return 0; 216 } 217 218 static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats) 219 { 220 struct task_struct *tsk, *first; 221 unsigned long flags; 222 int rc = -ESRCH; 223 224 /* 225 * Add additional stats from live tasks except zombie thread group 226 * leaders who are already counted with the dead tasks 227 */ 228 rcu_read_lock(); 229 first = find_task_by_vpid(tgid); 230 231 if (!first || !lock_task_sighand(first, &flags)) 232 goto out; 233 234 if (first->signal->stats) 235 memcpy(stats, first->signal->stats, sizeof(*stats)); 236 else 237 memset(stats, 0, sizeof(*stats)); 238 239 tsk = first; 240 do { 241 if (tsk->exit_state) 242 continue; 243 /* 244 * Accounting subsystem can call its functions here to 245 * fill in relevant parts of struct taskstsats as follows 246 * 247 * per-task-foo(stats, tsk); 248 */ 249 delayacct_add_tsk(stats, tsk); 250 251 stats->nvcsw += tsk->nvcsw; 252 stats->nivcsw += tsk->nivcsw; 253 } while_each_thread(first, tsk); 254 255 unlock_task_sighand(first, &flags); 256 rc = 0; 257 out: 258 rcu_read_unlock(); 259 260 stats->version = TASKSTATS_VERSION; 261 /* 262 * Accounting subsystems can also add calls here to modify 263 * fields of taskstats. 264 */ 265 return rc; 266 } 267 268 static void fill_tgid_exit(struct task_struct *tsk) 269 { 270 unsigned long flags; 271 272 spin_lock_irqsave(&tsk->sighand->siglock, flags); 273 if (!tsk->signal->stats) 274 goto ret; 275 276 /* 277 * Each accounting subsystem calls its functions here to 278 * accumalate its per-task stats for tsk, into the per-tgid structure 279 * 280 * per-task-foo(tsk->signal->stats, tsk); 281 */ 282 delayacct_add_tsk(tsk->signal->stats, tsk); 283 ret: 284 spin_unlock_irqrestore(&tsk->sighand->siglock, flags); 285 return; 286 } 287 288 static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd) 289 { 290 struct listener_list *listeners; 291 struct listener *s, *tmp, *s2; 292 unsigned int cpu; 293 int ret = 0; 294 295 if (!cpumask_subset(mask, cpu_possible_mask)) 296 return -EINVAL; 297 298 if (current_user_ns() != &init_user_ns) 299 return -EINVAL; 300 301 if (task_active_pid_ns(current) != &init_pid_ns) 302 return -EINVAL; 303 304 if (isadd == REGISTER) { 305 for_each_cpu(cpu, mask) { 306 s = kmalloc_node(sizeof(struct listener), 307 GFP_KERNEL, cpu_to_node(cpu)); 308 if (!s) { 309 ret = -ENOMEM; 310 goto cleanup; 311 } 312 s->pid = pid; 313 s->valid = 1; 314 315 listeners = &per_cpu(listener_array, cpu); 316 down_write(&listeners->sem); 317 list_for_each_entry(s2, &listeners->list, list) { 318 if (s2->pid == pid && s2->valid) 319 goto exists; 320 } 321 list_add(&s->list, &listeners->list); 322 s = NULL; 323 exists: 324 up_write(&listeners->sem); 325 kfree(s); /* nop if NULL */ 326 } 327 return 0; 328 } 329 330 /* Deregister or cleanup */ 331 cleanup: 332 for_each_cpu(cpu, mask) { 333 listeners = &per_cpu(listener_array, cpu); 334 down_write(&listeners->sem); 335 list_for_each_entry_safe(s, tmp, &listeners->list, list) { 336 if (s->pid == pid) { 337 list_del(&s->list); 338 kfree(s); 339 break; 340 } 341 } 342 up_write(&listeners->sem); 343 } 344 return ret; 345 } 346 347 static int parse(struct nlattr *na, struct cpumask *mask) 348 { 349 char *data; 350 int len; 351 int ret; 352 353 if (na == NULL) 354 return 1; 355 len = nla_len(na); 356 if (len > TASKSTATS_CPUMASK_MAXLEN) 357 return -E2BIG; 358 if (len < 1) 359 return -EINVAL; 360 data = kmalloc(len, GFP_KERNEL); 361 if (!data) 362 return -ENOMEM; 363 nla_strlcpy(data, na, len); 364 ret = cpulist_parse(data, mask); 365 kfree(data); 366 return ret; 367 } 368 369 #if defined(CONFIG_64BIT) && !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) 370 #define TASKSTATS_NEEDS_PADDING 1 371 #endif 372 373 static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid) 374 { 375 struct nlattr *na, *ret; 376 int aggr; 377 378 aggr = (type == TASKSTATS_TYPE_PID) 379 ? TASKSTATS_TYPE_AGGR_PID 380 : TASKSTATS_TYPE_AGGR_TGID; 381 382 /* 383 * The taskstats structure is internally aligned on 8 byte 384 * boundaries but the layout of the aggregrate reply, with 385 * two NLA headers and the pid (each 4 bytes), actually 386 * force the entire structure to be unaligned. This causes 387 * the kernel to issue unaligned access warnings on some 388 * architectures like ia64. Unfortunately, some software out there 389 * doesn't properly unroll the NLA packet and assumes that the start 390 * of the taskstats structure will always be 20 bytes from the start 391 * of the netlink payload. Aligning the start of the taskstats 392 * structure breaks this software, which we don't want. So, for now 393 * the alignment only happens on architectures that require it 394 * and those users will have to update to fixed versions of those 395 * packages. Space is reserved in the packet only when needed. 396 * This ifdef should be removed in several years e.g. 2012 once 397 * we can be confident that fixed versions are installed on most 398 * systems. We add the padding before the aggregate since the 399 * aggregate is already a defined type. 400 */ 401 #ifdef TASKSTATS_NEEDS_PADDING 402 if (nla_put(skb, TASKSTATS_TYPE_NULL, 0, NULL) < 0) 403 goto err; 404 #endif 405 na = nla_nest_start(skb, aggr); 406 if (!na) 407 goto err; 408 409 if (nla_put(skb, type, sizeof(pid), &pid) < 0) { 410 nla_nest_cancel(skb, na); 411 goto err; 412 } 413 ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats)); 414 if (!ret) { 415 nla_nest_cancel(skb, na); 416 goto err; 417 } 418 nla_nest_end(skb, na); 419 420 return nla_data(ret); 421 err: 422 return NULL; 423 } 424 425 static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info) 426 { 427 int rc = 0; 428 struct sk_buff *rep_skb; 429 struct cgroupstats *stats; 430 struct nlattr *na; 431 size_t size; 432 u32 fd; 433 struct fd f; 434 435 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD]; 436 if (!na) 437 return -EINVAL; 438 439 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]); 440 f = fdget(fd); 441 if (!f.file) 442 return 0; 443 444 size = nla_total_size(sizeof(struct cgroupstats)); 445 446 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb, 447 size); 448 if (rc < 0) 449 goto err; 450 451 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS, 452 sizeof(struct cgroupstats)); 453 if (na == NULL) { 454 nlmsg_free(rep_skb); 455 rc = -EMSGSIZE; 456 goto err; 457 } 458 459 stats = nla_data(na); 460 memset(stats, 0, sizeof(*stats)); 461 462 rc = cgroupstats_build(stats, f.file->f_path.dentry); 463 if (rc < 0) { 464 nlmsg_free(rep_skb); 465 goto err; 466 } 467 468 rc = send_reply(rep_skb, info); 469 470 err: 471 fdput(f); 472 return rc; 473 } 474 475 static int cmd_attr_register_cpumask(struct genl_info *info) 476 { 477 cpumask_var_t mask; 478 int rc; 479 480 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 481 return -ENOMEM; 482 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask); 483 if (rc < 0) 484 goto out; 485 rc = add_del_listener(info->snd_portid, mask, REGISTER); 486 out: 487 free_cpumask_var(mask); 488 return rc; 489 } 490 491 static int cmd_attr_deregister_cpumask(struct genl_info *info) 492 { 493 cpumask_var_t mask; 494 int rc; 495 496 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 497 return -ENOMEM; 498 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask); 499 if (rc < 0) 500 goto out; 501 rc = add_del_listener(info->snd_portid, mask, DEREGISTER); 502 out: 503 free_cpumask_var(mask); 504 return rc; 505 } 506 507 static size_t taskstats_packet_size(void) 508 { 509 size_t size; 510 511 size = nla_total_size(sizeof(u32)) + 512 nla_total_size(sizeof(struct taskstats)) + nla_total_size(0); 513 #ifdef TASKSTATS_NEEDS_PADDING 514 size += nla_total_size(0); /* Padding for alignment */ 515 #endif 516 return size; 517 } 518 519 static int cmd_attr_pid(struct genl_info *info) 520 { 521 struct taskstats *stats; 522 struct sk_buff *rep_skb; 523 size_t size; 524 u32 pid; 525 int rc; 526 527 size = taskstats_packet_size(); 528 529 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); 530 if (rc < 0) 531 return rc; 532 533 rc = -EINVAL; 534 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]); 535 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid); 536 if (!stats) 537 goto err; 538 539 rc = fill_stats_for_pid(pid, stats); 540 if (rc < 0) 541 goto err; 542 return send_reply(rep_skb, info); 543 err: 544 nlmsg_free(rep_skb); 545 return rc; 546 } 547 548 static int cmd_attr_tgid(struct genl_info *info) 549 { 550 struct taskstats *stats; 551 struct sk_buff *rep_skb; 552 size_t size; 553 u32 tgid; 554 int rc; 555 556 size = taskstats_packet_size(); 557 558 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); 559 if (rc < 0) 560 return rc; 561 562 rc = -EINVAL; 563 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]); 564 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid); 565 if (!stats) 566 goto err; 567 568 rc = fill_stats_for_tgid(tgid, stats); 569 if (rc < 0) 570 goto err; 571 return send_reply(rep_skb, info); 572 err: 573 nlmsg_free(rep_skb); 574 return rc; 575 } 576 577 static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info) 578 { 579 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK]) 580 return cmd_attr_register_cpumask(info); 581 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK]) 582 return cmd_attr_deregister_cpumask(info); 583 else if (info->attrs[TASKSTATS_CMD_ATTR_PID]) 584 return cmd_attr_pid(info); 585 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) 586 return cmd_attr_tgid(info); 587 else 588 return -EINVAL; 589 } 590 591 static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk) 592 { 593 struct signal_struct *sig = tsk->signal; 594 struct taskstats *stats; 595 596 if (sig->stats || thread_group_empty(tsk)) 597 goto ret; 598 599 /* No problem if kmem_cache_zalloc() fails */ 600 stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL); 601 602 spin_lock_irq(&tsk->sighand->siglock); 603 if (!sig->stats) { 604 sig->stats = stats; 605 stats = NULL; 606 } 607 spin_unlock_irq(&tsk->sighand->siglock); 608 609 if (stats) 610 kmem_cache_free(taskstats_cache, stats); 611 ret: 612 return sig->stats; 613 } 614 615 /* Send pid data out on exit */ 616 void taskstats_exit(struct task_struct *tsk, int group_dead) 617 { 618 int rc; 619 struct listener_list *listeners; 620 struct taskstats *stats; 621 struct sk_buff *rep_skb; 622 size_t size; 623 int is_thread_group; 624 625 if (!family_registered) 626 return; 627 628 /* 629 * Size includes space for nested attributes 630 */ 631 size = taskstats_packet_size(); 632 633 is_thread_group = !!taskstats_tgid_alloc(tsk); 634 if (is_thread_group) { 635 /* PID + STATS + TGID + STATS */ 636 size = 2 * size; 637 /* fill the tsk->signal->stats structure */ 638 fill_tgid_exit(tsk); 639 } 640 641 listeners = raw_cpu_ptr(&listener_array); 642 if (list_empty(&listeners->list)) 643 return; 644 645 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size); 646 if (rc < 0) 647 return; 648 649 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, 650 task_pid_nr_ns(tsk, &init_pid_ns)); 651 if (!stats) 652 goto err; 653 654 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats); 655 656 /* 657 * Doesn't matter if tsk is the leader or the last group member leaving 658 */ 659 if (!is_thread_group || !group_dead) 660 goto send; 661 662 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, 663 task_tgid_nr_ns(tsk, &init_pid_ns)); 664 if (!stats) 665 goto err; 666 667 memcpy(stats, tsk->signal->stats, sizeof(*stats)); 668 669 send: 670 send_cpu_listeners(rep_skb, listeners); 671 return; 672 err: 673 nlmsg_free(rep_skb); 674 } 675 676 static const struct genl_ops taskstats_ops[] = { 677 { 678 .cmd = TASKSTATS_CMD_GET, 679 .doit = taskstats_user_cmd, 680 .policy = taskstats_cmd_get_policy, 681 .flags = GENL_ADMIN_PERM, 682 }, 683 { 684 .cmd = CGROUPSTATS_CMD_GET, 685 .doit = cgroupstats_user_cmd, 686 .policy = cgroupstats_cmd_get_policy, 687 }, 688 }; 689 690 /* Needed early in initialization */ 691 void __init taskstats_init_early(void) 692 { 693 unsigned int i; 694 695 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC); 696 for_each_possible_cpu(i) { 697 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list)); 698 init_rwsem(&(per_cpu(listener_array, i).sem)); 699 } 700 } 701 702 static int __init taskstats_init(void) 703 { 704 int rc; 705 706 rc = genl_register_family_with_ops(&family, taskstats_ops); 707 if (rc) 708 return rc; 709 710 family_registered = 1; 711 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION); 712 return 0; 713 } 714 715 /* 716 * late initcall ensures initialization of statistics collection 717 * mechanisms precedes initialization of the taskstats interface 718 */ 719 late_initcall(taskstats_init); 720