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 static const struct nla_policy cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] = { 53 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 }, 54 }; 55 56 struct listener { 57 struct list_head list; 58 pid_t pid; 59 char valid; 60 }; 61 62 struct listener_list { 63 struct rw_semaphore sem; 64 struct list_head list; 65 }; 66 static DEFINE_PER_CPU(struct listener_list, listener_array); 67 68 enum actions { 69 REGISTER, 70 DEREGISTER, 71 CPU_DONT_CARE 72 }; 73 74 static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp, 75 size_t size) 76 { 77 struct sk_buff *skb; 78 void *reply; 79 80 /* 81 * If new attributes are added, please revisit this allocation 82 */ 83 skb = genlmsg_new(size, GFP_KERNEL); 84 if (!skb) 85 return -ENOMEM; 86 87 if (!info) { 88 int seq = this_cpu_inc_return(taskstats_seqnum) - 1; 89 90 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd); 91 } else 92 reply = genlmsg_put_reply(skb, info, &family, 0, cmd); 93 if (reply == NULL) { 94 nlmsg_free(skb); 95 return -EINVAL; 96 } 97 98 *skbp = skb; 99 return 0; 100 } 101 102 /* 103 * Send taskstats data in @skb to listener with nl_pid @pid 104 */ 105 static int send_reply(struct sk_buff *skb, struct genl_info *info) 106 { 107 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb)); 108 void *reply = genlmsg_data(genlhdr); 109 110 genlmsg_end(skb, reply); 111 112 return genlmsg_reply(skb, info); 113 } 114 115 /* 116 * Send taskstats data in @skb to listeners registered for @cpu's exit data 117 */ 118 static void send_cpu_listeners(struct sk_buff *skb, 119 struct listener_list *listeners) 120 { 121 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb)); 122 struct listener *s, *tmp; 123 struct sk_buff *skb_next, *skb_cur = skb; 124 void *reply = genlmsg_data(genlhdr); 125 int rc, delcount = 0; 126 127 genlmsg_end(skb, reply); 128 129 rc = 0; 130 down_read(&listeners->sem); 131 list_for_each_entry(s, &listeners->list, list) { 132 skb_next = NULL; 133 if (!list_is_last(&s->list, &listeners->list)) { 134 skb_next = skb_clone(skb_cur, GFP_KERNEL); 135 if (!skb_next) 136 break; 137 } 138 rc = genlmsg_unicast(&init_net, skb_cur, s->pid); 139 if (rc == -ECONNREFUSED) { 140 s->valid = 0; 141 delcount++; 142 } 143 skb_cur = skb_next; 144 } 145 up_read(&listeners->sem); 146 147 if (skb_cur) 148 nlmsg_free(skb_cur); 149 150 if (!delcount) 151 return; 152 153 /* Delete invalidated entries */ 154 down_write(&listeners->sem); 155 list_for_each_entry_safe(s, tmp, &listeners->list, list) { 156 if (!s->valid) { 157 list_del(&s->list); 158 kfree(s); 159 } 160 } 161 up_write(&listeners->sem); 162 } 163 164 static void fill_stats(struct user_namespace *user_ns, 165 struct pid_namespace *pid_ns, 166 struct task_struct *tsk, struct taskstats *stats) 167 { 168 memset(stats, 0, sizeof(*stats)); 169 /* 170 * Each accounting subsystem adds calls to its functions to 171 * fill in relevant parts of struct taskstsats as follows 172 * 173 * per-task-foo(stats, tsk); 174 */ 175 176 delayacct_add_tsk(stats, tsk); 177 178 /* fill in basic acct fields */ 179 stats->version = TASKSTATS_VERSION; 180 stats->nvcsw = tsk->nvcsw; 181 stats->nivcsw = tsk->nivcsw; 182 bacct_add_tsk(user_ns, pid_ns, stats, tsk); 183 184 /* fill in extended acct fields */ 185 xacct_add_tsk(stats, tsk); 186 } 187 188 static int fill_stats_for_pid(pid_t pid, struct taskstats *stats) 189 { 190 struct task_struct *tsk; 191 192 rcu_read_lock(); 193 tsk = find_task_by_vpid(pid); 194 if (tsk) 195 get_task_struct(tsk); 196 rcu_read_unlock(); 197 if (!tsk) 198 return -ESRCH; 199 fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats); 200 put_task_struct(tsk); 201 return 0; 202 } 203 204 static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats) 205 { 206 struct task_struct *tsk, *first; 207 unsigned long flags; 208 int rc = -ESRCH; 209 210 /* 211 * Add additional stats from live tasks except zombie thread group 212 * leaders who are already counted with the dead tasks 213 */ 214 rcu_read_lock(); 215 first = find_task_by_vpid(tgid); 216 217 if (!first || !lock_task_sighand(first, &flags)) 218 goto out; 219 220 if (first->signal->stats) 221 memcpy(stats, first->signal->stats, sizeof(*stats)); 222 else 223 memset(stats, 0, sizeof(*stats)); 224 225 tsk = first; 226 do { 227 if (tsk->exit_state) 228 continue; 229 /* 230 * Accounting subsystem can call its functions here to 231 * fill in relevant parts of struct taskstsats as follows 232 * 233 * per-task-foo(stats, tsk); 234 */ 235 delayacct_add_tsk(stats, tsk); 236 237 stats->nvcsw += tsk->nvcsw; 238 stats->nivcsw += tsk->nivcsw; 239 } while_each_thread(first, tsk); 240 241 unlock_task_sighand(first, &flags); 242 rc = 0; 243 out: 244 rcu_read_unlock(); 245 246 stats->version = TASKSTATS_VERSION; 247 /* 248 * Accounting subsystems can also add calls here to modify 249 * fields of taskstats. 250 */ 251 return rc; 252 } 253 254 static void fill_tgid_exit(struct task_struct *tsk) 255 { 256 unsigned long flags; 257 258 spin_lock_irqsave(&tsk->sighand->siglock, flags); 259 if (!tsk->signal->stats) 260 goto ret; 261 262 /* 263 * Each accounting subsystem calls its functions here to 264 * accumalate its per-task stats for tsk, into the per-tgid structure 265 * 266 * per-task-foo(tsk->signal->stats, tsk); 267 */ 268 delayacct_add_tsk(tsk->signal->stats, tsk); 269 ret: 270 spin_unlock_irqrestore(&tsk->sighand->siglock, flags); 271 return; 272 } 273 274 static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd) 275 { 276 struct listener_list *listeners; 277 struct listener *s, *tmp, *s2; 278 unsigned int cpu; 279 int ret = 0; 280 281 if (!cpumask_subset(mask, cpu_possible_mask)) 282 return -EINVAL; 283 284 if (current_user_ns() != &init_user_ns) 285 return -EINVAL; 286 287 if (task_active_pid_ns(current) != &init_pid_ns) 288 return -EINVAL; 289 290 if (isadd == REGISTER) { 291 for_each_cpu(cpu, mask) { 292 s = kmalloc_node(sizeof(struct listener), 293 GFP_KERNEL, cpu_to_node(cpu)); 294 if (!s) { 295 ret = -ENOMEM; 296 goto cleanup; 297 } 298 s->pid = pid; 299 s->valid = 1; 300 301 listeners = &per_cpu(listener_array, cpu); 302 down_write(&listeners->sem); 303 list_for_each_entry(s2, &listeners->list, list) { 304 if (s2->pid == pid && s2->valid) 305 goto exists; 306 } 307 list_add(&s->list, &listeners->list); 308 s = NULL; 309 exists: 310 up_write(&listeners->sem); 311 kfree(s); /* nop if NULL */ 312 } 313 return 0; 314 } 315 316 /* Deregister or cleanup */ 317 cleanup: 318 for_each_cpu(cpu, mask) { 319 listeners = &per_cpu(listener_array, cpu); 320 down_write(&listeners->sem); 321 list_for_each_entry_safe(s, tmp, &listeners->list, list) { 322 if (s->pid == pid) { 323 list_del(&s->list); 324 kfree(s); 325 break; 326 } 327 } 328 up_write(&listeners->sem); 329 } 330 return ret; 331 } 332 333 static int parse(struct nlattr *na, struct cpumask *mask) 334 { 335 char *data; 336 int len; 337 int ret; 338 339 if (na == NULL) 340 return 1; 341 len = nla_len(na); 342 if (len > TASKSTATS_CPUMASK_MAXLEN) 343 return -E2BIG; 344 if (len < 1) 345 return -EINVAL; 346 data = kmalloc(len, GFP_KERNEL); 347 if (!data) 348 return -ENOMEM; 349 nla_strlcpy(data, na, len); 350 ret = cpulist_parse(data, mask); 351 kfree(data); 352 return ret; 353 } 354 355 static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid) 356 { 357 struct nlattr *na, *ret; 358 int aggr; 359 360 aggr = (type == TASKSTATS_TYPE_PID) 361 ? TASKSTATS_TYPE_AGGR_PID 362 : TASKSTATS_TYPE_AGGR_TGID; 363 364 na = nla_nest_start(skb, aggr); 365 if (!na) 366 goto err; 367 368 if (nla_put(skb, type, sizeof(pid), &pid) < 0) { 369 nla_nest_cancel(skb, na); 370 goto err; 371 } 372 ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS, 373 sizeof(struct taskstats), TASKSTATS_TYPE_NULL); 374 if (!ret) { 375 nla_nest_cancel(skb, na); 376 goto err; 377 } 378 nla_nest_end(skb, na); 379 380 return nla_data(ret); 381 err: 382 return NULL; 383 } 384 385 static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info) 386 { 387 int rc = 0; 388 struct sk_buff *rep_skb; 389 struct cgroupstats *stats; 390 struct nlattr *na; 391 size_t size; 392 u32 fd; 393 struct fd f; 394 395 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD]; 396 if (!na) 397 return -EINVAL; 398 399 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]); 400 f = fdget(fd); 401 if (!f.file) 402 return 0; 403 404 size = nla_total_size(sizeof(struct cgroupstats)); 405 406 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb, 407 size); 408 if (rc < 0) 409 goto err; 410 411 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS, 412 sizeof(struct cgroupstats)); 413 if (na == NULL) { 414 nlmsg_free(rep_skb); 415 rc = -EMSGSIZE; 416 goto err; 417 } 418 419 stats = nla_data(na); 420 memset(stats, 0, sizeof(*stats)); 421 422 rc = cgroupstats_build(stats, f.file->f_path.dentry); 423 if (rc < 0) { 424 nlmsg_free(rep_skb); 425 goto err; 426 } 427 428 rc = send_reply(rep_skb, info); 429 430 err: 431 fdput(f); 432 return rc; 433 } 434 435 static int cmd_attr_register_cpumask(struct genl_info *info) 436 { 437 cpumask_var_t mask; 438 int rc; 439 440 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 441 return -ENOMEM; 442 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask); 443 if (rc < 0) 444 goto out; 445 rc = add_del_listener(info->snd_portid, mask, REGISTER); 446 out: 447 free_cpumask_var(mask); 448 return rc; 449 } 450 451 static int cmd_attr_deregister_cpumask(struct genl_info *info) 452 { 453 cpumask_var_t mask; 454 int rc; 455 456 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 457 return -ENOMEM; 458 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask); 459 if (rc < 0) 460 goto out; 461 rc = add_del_listener(info->snd_portid, mask, DEREGISTER); 462 out: 463 free_cpumask_var(mask); 464 return rc; 465 } 466 467 static size_t taskstats_packet_size(void) 468 { 469 size_t size; 470 471 size = nla_total_size(sizeof(u32)) + 472 nla_total_size_64bit(sizeof(struct taskstats)) + 473 nla_total_size(0); 474 475 return size; 476 } 477 478 static int cmd_attr_pid(struct genl_info *info) 479 { 480 struct taskstats *stats; 481 struct sk_buff *rep_skb; 482 size_t size; 483 u32 pid; 484 int rc; 485 486 size = taskstats_packet_size(); 487 488 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); 489 if (rc < 0) 490 return rc; 491 492 rc = -EINVAL; 493 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]); 494 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid); 495 if (!stats) 496 goto err; 497 498 rc = fill_stats_for_pid(pid, stats); 499 if (rc < 0) 500 goto err; 501 return send_reply(rep_skb, info); 502 err: 503 nlmsg_free(rep_skb); 504 return rc; 505 } 506 507 static int cmd_attr_tgid(struct genl_info *info) 508 { 509 struct taskstats *stats; 510 struct sk_buff *rep_skb; 511 size_t size; 512 u32 tgid; 513 int rc; 514 515 size = taskstats_packet_size(); 516 517 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); 518 if (rc < 0) 519 return rc; 520 521 rc = -EINVAL; 522 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]); 523 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid); 524 if (!stats) 525 goto err; 526 527 rc = fill_stats_for_tgid(tgid, stats); 528 if (rc < 0) 529 goto err; 530 return send_reply(rep_skb, info); 531 err: 532 nlmsg_free(rep_skb); 533 return rc; 534 } 535 536 static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info) 537 { 538 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK]) 539 return cmd_attr_register_cpumask(info); 540 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK]) 541 return cmd_attr_deregister_cpumask(info); 542 else if (info->attrs[TASKSTATS_CMD_ATTR_PID]) 543 return cmd_attr_pid(info); 544 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) 545 return cmd_attr_tgid(info); 546 else 547 return -EINVAL; 548 } 549 550 static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk) 551 { 552 struct signal_struct *sig = tsk->signal; 553 struct taskstats *stats; 554 555 if (sig->stats || thread_group_empty(tsk)) 556 goto ret; 557 558 /* No problem if kmem_cache_zalloc() fails */ 559 stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL); 560 561 spin_lock_irq(&tsk->sighand->siglock); 562 if (!sig->stats) { 563 sig->stats = stats; 564 stats = NULL; 565 } 566 spin_unlock_irq(&tsk->sighand->siglock); 567 568 if (stats) 569 kmem_cache_free(taskstats_cache, stats); 570 ret: 571 return sig->stats; 572 } 573 574 /* Send pid data out on exit */ 575 void taskstats_exit(struct task_struct *tsk, int group_dead) 576 { 577 int rc; 578 struct listener_list *listeners; 579 struct taskstats *stats; 580 struct sk_buff *rep_skb; 581 size_t size; 582 int is_thread_group; 583 584 if (!family_registered) 585 return; 586 587 /* 588 * Size includes space for nested attributes 589 */ 590 size = taskstats_packet_size(); 591 592 is_thread_group = !!taskstats_tgid_alloc(tsk); 593 if (is_thread_group) { 594 /* PID + STATS + TGID + STATS */ 595 size = 2 * size; 596 /* fill the tsk->signal->stats structure */ 597 fill_tgid_exit(tsk); 598 } 599 600 listeners = raw_cpu_ptr(&listener_array); 601 if (list_empty(&listeners->list)) 602 return; 603 604 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size); 605 if (rc < 0) 606 return; 607 608 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, 609 task_pid_nr_ns(tsk, &init_pid_ns)); 610 if (!stats) 611 goto err; 612 613 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats); 614 615 /* 616 * Doesn't matter if tsk is the leader or the last group member leaving 617 */ 618 if (!is_thread_group || !group_dead) 619 goto send; 620 621 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, 622 task_tgid_nr_ns(tsk, &init_pid_ns)); 623 if (!stats) 624 goto err; 625 626 memcpy(stats, tsk->signal->stats, sizeof(*stats)); 627 628 send: 629 send_cpu_listeners(rep_skb, listeners); 630 return; 631 err: 632 nlmsg_free(rep_skb); 633 } 634 635 static const struct genl_ops taskstats_ops[] = { 636 { 637 .cmd = TASKSTATS_CMD_GET, 638 .doit = taskstats_user_cmd, 639 .policy = taskstats_cmd_get_policy, 640 .flags = GENL_ADMIN_PERM, 641 }, 642 { 643 .cmd = CGROUPSTATS_CMD_GET, 644 .doit = cgroupstats_user_cmd, 645 .policy = cgroupstats_cmd_get_policy, 646 }, 647 }; 648 649 static struct genl_family family = { 650 .name = TASKSTATS_GENL_NAME, 651 .version = TASKSTATS_GENL_VERSION, 652 .maxattr = TASKSTATS_CMD_ATTR_MAX, 653 .module = THIS_MODULE, 654 .ops = taskstats_ops, 655 .n_ops = ARRAY_SIZE(taskstats_ops), 656 }; 657 658 /* Needed early in initialization */ 659 void __init taskstats_init_early(void) 660 { 661 unsigned int i; 662 663 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC); 664 for_each_possible_cpu(i) { 665 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list)); 666 init_rwsem(&(per_cpu(listener_array, i).sem)); 667 } 668 } 669 670 static int __init taskstats_init(void) 671 { 672 int rc; 673 674 rc = genl_register_family(&family); 675 if (rc) 676 return rc; 677 678 family_registered = 1; 679 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION); 680 return 0; 681 } 682 683 /* 684 * late initcall ensures initialization of statistics collection 685 * mechanisms precedes initialization of the taskstats interface 686 */ 687 late_initcall(taskstats_init); 688