1 /* 2 * linux/fs/proc/array.c 3 * 4 * Copyright (C) 1992 by Linus Torvalds 5 * based on ideas by Darren Senn 6 * 7 * Fixes: 8 * Michael. K. Johnson: stat,statm extensions. 9 * <johnsonm@stolaf.edu> 10 * 11 * Pauline Middelink : Made cmdline,envline only break at '\0's, to 12 * make sure SET_PROCTITLE works. Also removed 13 * bad '!' which forced address recalculation for 14 * EVERY character on the current page. 15 * <middelin@polyware.iaf.nl> 16 * 17 * Danny ter Haar : added cpuinfo 18 * <dth@cistron.nl> 19 * 20 * Alessandro Rubini : profile extension. 21 * <rubini@ipvvis.unipv.it> 22 * 23 * Jeff Tranter : added BogoMips field to cpuinfo 24 * <Jeff_Tranter@Mitel.COM> 25 * 26 * Bruno Haible : remove 4K limit for the maps file 27 * <haible@ma2s2.mathematik.uni-karlsruhe.de> 28 * 29 * Yves Arrouye : remove removal of trailing spaces in get_array. 30 * <Yves.Arrouye@marin.fdn.fr> 31 * 32 * Jerome Forissier : added per-CPU time information to /proc/stat 33 * and /proc/<pid>/cpu extension 34 * <forissier@isia.cma.fr> 35 * - Incorporation and non-SMP safe operation 36 * of forissier patch in 2.1.78 by 37 * Hans Marcus <crowbar@concepts.nl> 38 * 39 * aeb@cwi.nl : /proc/partitions 40 * 41 * 42 * Alan Cox : security fixes. 43 * <alan@lxorguk.ukuu.org.uk> 44 * 45 * Al Viro : safe handling of mm_struct 46 * 47 * Gerhard Wichert : added BIGMEM support 48 * Siemens AG <Gerhard.Wichert@pdb.siemens.de> 49 * 50 * Al Viro & Jeff Garzik : moved most of the thing into base.c and 51 * : proc_misc.c. The rest may eventually go into 52 * : base.c too. 53 */ 54 55 #include <linux/types.h> 56 #include <linux/errno.h> 57 #include <linux/time.h> 58 #include <linux/kernel.h> 59 #include <linux/kernel_stat.h> 60 #include <linux/tty.h> 61 #include <linux/string.h> 62 #include <linux/mman.h> 63 #include <linux/proc_fs.h> 64 #include <linux/ioport.h> 65 #include <linux/uaccess.h> 66 #include <linux/io.h> 67 #include <linux/mm.h> 68 #include <linux/hugetlb.h> 69 #include <linux/pagemap.h> 70 #include <linux/swap.h> 71 #include <linux/smp.h> 72 #include <linux/signal.h> 73 #include <linux/highmem.h> 74 #include <linux/file.h> 75 #include <linux/fdtable.h> 76 #include <linux/times.h> 77 #include <linux/cpuset.h> 78 #include <linux/rcupdate.h> 79 #include <linux/delayacct.h> 80 #include <linux/seq_file.h> 81 #include <linux/pid_namespace.h> 82 #include <linux/ptrace.h> 83 #include <linux/tracehook.h> 84 #include <linux/user_namespace.h> 85 86 #include <asm/pgtable.h> 87 #include <asm/processor.h> 88 #include "internal.h" 89 90 static inline void task_name(struct seq_file *m, struct task_struct *p) 91 { 92 int i; 93 char *buf, *end; 94 char *name; 95 char tcomm[sizeof(p->comm)]; 96 97 get_task_comm(tcomm, p); 98 99 seq_puts(m, "Name:\t"); 100 end = m->buf + m->size; 101 buf = m->buf + m->count; 102 name = tcomm; 103 i = sizeof(tcomm); 104 while (i && (buf < end)) { 105 unsigned char c = *name; 106 name++; 107 i--; 108 *buf = c; 109 if (!c) 110 break; 111 if (c == '\\') { 112 buf++; 113 if (buf < end) 114 *buf++ = c; 115 continue; 116 } 117 if (c == '\n') { 118 *buf++ = '\\'; 119 if (buf < end) 120 *buf++ = 'n'; 121 continue; 122 } 123 buf++; 124 } 125 m->count = buf - m->buf; 126 seq_putc(m, '\n'); 127 } 128 129 /* 130 * The task state array is a strange "bitmap" of 131 * reasons to sleep. Thus "running" is zero, and 132 * you can test for combinations of others with 133 * simple bit tests. 134 */ 135 static const char * const task_state_array[] = { 136 "R (running)", /* 0 */ 137 "S (sleeping)", /* 1 */ 138 "D (disk sleep)", /* 2 */ 139 "T (stopped)", /* 4 */ 140 "t (tracing stop)", /* 8 */ 141 "Z (zombie)", /* 16 */ 142 "X (dead)", /* 32 */ 143 "x (dead)", /* 64 */ 144 "K (wakekill)", /* 128 */ 145 "W (waking)", /* 256 */ 146 "P (parked)", /* 512 */ 147 }; 148 149 static inline const char *get_task_state(struct task_struct *tsk) 150 { 151 unsigned int state = (tsk->state & TASK_REPORT) | tsk->exit_state; 152 const char * const *p = &task_state_array[0]; 153 154 BUILD_BUG_ON(1 + ilog2(TASK_STATE_MAX) != ARRAY_SIZE(task_state_array)); 155 156 while (state) { 157 p++; 158 state >>= 1; 159 } 160 return *p; 161 } 162 163 static inline void task_state(struct seq_file *m, struct pid_namespace *ns, 164 struct pid *pid, struct task_struct *p) 165 { 166 struct user_namespace *user_ns = seq_user_ns(m); 167 struct group_info *group_info; 168 int g; 169 struct fdtable *fdt = NULL; 170 const struct cred *cred; 171 pid_t ppid, tpid; 172 173 rcu_read_lock(); 174 ppid = pid_alive(p) ? 175 task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0; 176 tpid = 0; 177 if (pid_alive(p)) { 178 struct task_struct *tracer = ptrace_parent(p); 179 if (tracer) 180 tpid = task_pid_nr_ns(tracer, ns); 181 } 182 cred = get_task_cred(p); 183 seq_printf(m, 184 "State:\t%s\n" 185 "Tgid:\t%d\n" 186 "Ngid:\t%d\n" 187 "Pid:\t%d\n" 188 "PPid:\t%d\n" 189 "TracerPid:\t%d\n" 190 "Uid:\t%d\t%d\t%d\t%d\n" 191 "Gid:\t%d\t%d\t%d\t%d\n", 192 get_task_state(p), 193 task_tgid_nr_ns(p, ns), 194 task_numa_group_id(p), 195 pid_nr_ns(pid, ns), 196 ppid, tpid, 197 from_kuid_munged(user_ns, cred->uid), 198 from_kuid_munged(user_ns, cred->euid), 199 from_kuid_munged(user_ns, cred->suid), 200 from_kuid_munged(user_ns, cred->fsuid), 201 from_kgid_munged(user_ns, cred->gid), 202 from_kgid_munged(user_ns, cred->egid), 203 from_kgid_munged(user_ns, cred->sgid), 204 from_kgid_munged(user_ns, cred->fsgid)); 205 206 task_lock(p); 207 if (p->files) 208 fdt = files_fdtable(p->files); 209 seq_printf(m, 210 "FDSize:\t%d\n" 211 "Groups:\t", 212 fdt ? fdt->max_fds : 0); 213 rcu_read_unlock(); 214 215 group_info = cred->group_info; 216 task_unlock(p); 217 218 for (g = 0; g < group_info->ngroups; g++) 219 seq_printf(m, "%d ", 220 from_kgid_munged(user_ns, GROUP_AT(group_info, g))); 221 put_cred(cred); 222 223 seq_putc(m, '\n'); 224 } 225 226 void render_sigset_t(struct seq_file *m, const char *header, 227 sigset_t *set) 228 { 229 int i; 230 231 seq_puts(m, header); 232 233 i = _NSIG; 234 do { 235 int x = 0; 236 237 i -= 4; 238 if (sigismember(set, i+1)) x |= 1; 239 if (sigismember(set, i+2)) x |= 2; 240 if (sigismember(set, i+3)) x |= 4; 241 if (sigismember(set, i+4)) x |= 8; 242 seq_printf(m, "%x", x); 243 } while (i >= 4); 244 245 seq_putc(m, '\n'); 246 } 247 248 static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign, 249 sigset_t *catch) 250 { 251 struct k_sigaction *k; 252 int i; 253 254 k = p->sighand->action; 255 for (i = 1; i <= _NSIG; ++i, ++k) { 256 if (k->sa.sa_handler == SIG_IGN) 257 sigaddset(ign, i); 258 else if (k->sa.sa_handler != SIG_DFL) 259 sigaddset(catch, i); 260 } 261 } 262 263 static inline void task_sig(struct seq_file *m, struct task_struct *p) 264 { 265 unsigned long flags; 266 sigset_t pending, shpending, blocked, ignored, caught; 267 int num_threads = 0; 268 unsigned long qsize = 0; 269 unsigned long qlim = 0; 270 271 sigemptyset(&pending); 272 sigemptyset(&shpending); 273 sigemptyset(&blocked); 274 sigemptyset(&ignored); 275 sigemptyset(&caught); 276 277 if (lock_task_sighand(p, &flags)) { 278 pending = p->pending.signal; 279 shpending = p->signal->shared_pending.signal; 280 blocked = p->blocked; 281 collect_sigign_sigcatch(p, &ignored, &caught); 282 num_threads = get_nr_threads(p); 283 rcu_read_lock(); /* FIXME: is this correct? */ 284 qsize = atomic_read(&__task_cred(p)->user->sigpending); 285 rcu_read_unlock(); 286 qlim = task_rlimit(p, RLIMIT_SIGPENDING); 287 unlock_task_sighand(p, &flags); 288 } 289 290 seq_printf(m, "Threads:\t%d\n", num_threads); 291 seq_printf(m, "SigQ:\t%lu/%lu\n", qsize, qlim); 292 293 /* render them all */ 294 render_sigset_t(m, "SigPnd:\t", &pending); 295 render_sigset_t(m, "ShdPnd:\t", &shpending); 296 render_sigset_t(m, "SigBlk:\t", &blocked); 297 render_sigset_t(m, "SigIgn:\t", &ignored); 298 render_sigset_t(m, "SigCgt:\t", &caught); 299 } 300 301 static void render_cap_t(struct seq_file *m, const char *header, 302 kernel_cap_t *a) 303 { 304 unsigned __capi; 305 306 seq_puts(m, header); 307 CAP_FOR_EACH_U32(__capi) { 308 seq_printf(m, "%08x", 309 a->cap[(_KERNEL_CAPABILITY_U32S-1) - __capi]); 310 } 311 seq_putc(m, '\n'); 312 } 313 314 /* Remove non-existent capabilities */ 315 #define NORM_CAPS(v) (v.cap[CAP_TO_INDEX(CAP_LAST_CAP)] &= \ 316 CAP_TO_MASK(CAP_LAST_CAP + 1) - 1) 317 318 static inline void task_cap(struct seq_file *m, struct task_struct *p) 319 { 320 const struct cred *cred; 321 kernel_cap_t cap_inheritable, cap_permitted, cap_effective, cap_bset; 322 323 rcu_read_lock(); 324 cred = __task_cred(p); 325 cap_inheritable = cred->cap_inheritable; 326 cap_permitted = cred->cap_permitted; 327 cap_effective = cred->cap_effective; 328 cap_bset = cred->cap_bset; 329 rcu_read_unlock(); 330 331 NORM_CAPS(cap_inheritable); 332 NORM_CAPS(cap_permitted); 333 NORM_CAPS(cap_effective); 334 NORM_CAPS(cap_bset); 335 336 render_cap_t(m, "CapInh:\t", &cap_inheritable); 337 render_cap_t(m, "CapPrm:\t", &cap_permitted); 338 render_cap_t(m, "CapEff:\t", &cap_effective); 339 render_cap_t(m, "CapBnd:\t", &cap_bset); 340 } 341 342 static inline void task_seccomp(struct seq_file *m, struct task_struct *p) 343 { 344 #ifdef CONFIG_SECCOMP 345 seq_printf(m, "Seccomp:\t%d\n", p->seccomp.mode); 346 #endif 347 } 348 349 static inline void task_context_switch_counts(struct seq_file *m, 350 struct task_struct *p) 351 { 352 seq_printf(m, "voluntary_ctxt_switches:\t%lu\n" 353 "nonvoluntary_ctxt_switches:\t%lu\n", 354 p->nvcsw, 355 p->nivcsw); 356 } 357 358 static void task_cpus_allowed(struct seq_file *m, struct task_struct *task) 359 { 360 seq_puts(m, "Cpus_allowed:\t"); 361 seq_cpumask(m, &task->cpus_allowed); 362 seq_putc(m, '\n'); 363 seq_puts(m, "Cpus_allowed_list:\t"); 364 seq_cpumask_list(m, &task->cpus_allowed); 365 seq_putc(m, '\n'); 366 } 367 368 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, 369 struct pid *pid, struct task_struct *task) 370 { 371 struct mm_struct *mm = get_task_mm(task); 372 373 task_name(m, task); 374 task_state(m, ns, pid, task); 375 376 if (mm) { 377 task_mem(m, mm); 378 mmput(mm); 379 } 380 task_sig(m, task); 381 task_cap(m, task); 382 task_seccomp(m, task); 383 task_cpus_allowed(m, task); 384 cpuset_task_status_allowed(m, task); 385 task_context_switch_counts(m, task); 386 return 0; 387 } 388 389 static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, 390 struct pid *pid, struct task_struct *task, int whole) 391 { 392 unsigned long vsize, eip, esp, wchan = ~0UL; 393 int priority, nice; 394 int tty_pgrp = -1, tty_nr = 0; 395 sigset_t sigign, sigcatch; 396 char state; 397 pid_t ppid = 0, pgid = -1, sid = -1; 398 int num_threads = 0; 399 int permitted; 400 struct mm_struct *mm; 401 unsigned long long start_time; 402 unsigned long cmin_flt = 0, cmaj_flt = 0; 403 unsigned long min_flt = 0, maj_flt = 0; 404 cputime_t cutime, cstime, utime, stime; 405 cputime_t cgtime, gtime; 406 unsigned long rsslim = 0; 407 char tcomm[sizeof(task->comm)]; 408 unsigned long flags; 409 410 state = *get_task_state(task); 411 vsize = eip = esp = 0; 412 permitted = ptrace_may_access(task, PTRACE_MODE_READ | PTRACE_MODE_NOAUDIT); 413 mm = get_task_mm(task); 414 if (mm) { 415 vsize = task_vsize(mm); 416 if (permitted) { 417 eip = KSTK_EIP(task); 418 esp = KSTK_ESP(task); 419 } 420 } 421 422 get_task_comm(tcomm, task); 423 424 sigemptyset(&sigign); 425 sigemptyset(&sigcatch); 426 cutime = cstime = utime = stime = 0; 427 cgtime = gtime = 0; 428 429 if (lock_task_sighand(task, &flags)) { 430 struct signal_struct *sig = task->signal; 431 432 if (sig->tty) { 433 struct pid *pgrp = tty_get_pgrp(sig->tty); 434 tty_pgrp = pid_nr_ns(pgrp, ns); 435 put_pid(pgrp); 436 tty_nr = new_encode_dev(tty_devnum(sig->tty)); 437 } 438 439 num_threads = get_nr_threads(task); 440 collect_sigign_sigcatch(task, &sigign, &sigcatch); 441 442 cmin_flt = sig->cmin_flt; 443 cmaj_flt = sig->cmaj_flt; 444 cutime = sig->cutime; 445 cstime = sig->cstime; 446 cgtime = sig->cgtime; 447 rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur); 448 449 /* add up live thread stats at the group level */ 450 if (whole) { 451 struct task_struct *t = task; 452 do { 453 min_flt += t->min_flt; 454 maj_flt += t->maj_flt; 455 gtime += task_gtime(t); 456 t = next_thread(t); 457 } while (t != task); 458 459 min_flt += sig->min_flt; 460 maj_flt += sig->maj_flt; 461 thread_group_cputime_adjusted(task, &utime, &stime); 462 gtime += sig->gtime; 463 } 464 465 sid = task_session_nr_ns(task, ns); 466 ppid = task_tgid_nr_ns(task->real_parent, ns); 467 pgid = task_pgrp_nr_ns(task, ns); 468 469 unlock_task_sighand(task, &flags); 470 } 471 472 if (permitted && (!whole || num_threads < 2)) 473 wchan = get_wchan(task); 474 if (!whole) { 475 min_flt = task->min_flt; 476 maj_flt = task->maj_flt; 477 task_cputime_adjusted(task, &utime, &stime); 478 gtime = task_gtime(task); 479 } 480 481 /* scale priority and nice values from timeslices to -20..20 */ 482 /* to make it look like a "normal" Unix priority/nice value */ 483 priority = task_prio(task); 484 nice = task_nice(task); 485 486 /* Temporary variable needed for gcc-2.96 */ 487 /* convert timespec -> nsec*/ 488 start_time = 489 (unsigned long long)task->real_start_time.tv_sec * NSEC_PER_SEC 490 + task->real_start_time.tv_nsec; 491 /* convert nsec -> ticks */ 492 start_time = nsec_to_clock_t(start_time); 493 494 seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state); 495 seq_put_decimal_ll(m, ' ', ppid); 496 seq_put_decimal_ll(m, ' ', pgid); 497 seq_put_decimal_ll(m, ' ', sid); 498 seq_put_decimal_ll(m, ' ', tty_nr); 499 seq_put_decimal_ll(m, ' ', tty_pgrp); 500 seq_put_decimal_ull(m, ' ', task->flags); 501 seq_put_decimal_ull(m, ' ', min_flt); 502 seq_put_decimal_ull(m, ' ', cmin_flt); 503 seq_put_decimal_ull(m, ' ', maj_flt); 504 seq_put_decimal_ull(m, ' ', cmaj_flt); 505 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime)); 506 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime)); 507 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime)); 508 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime)); 509 seq_put_decimal_ll(m, ' ', priority); 510 seq_put_decimal_ll(m, ' ', nice); 511 seq_put_decimal_ll(m, ' ', num_threads); 512 seq_put_decimal_ull(m, ' ', 0); 513 seq_put_decimal_ull(m, ' ', start_time); 514 seq_put_decimal_ull(m, ' ', vsize); 515 seq_put_decimal_ull(m, ' ', mm ? get_mm_rss(mm) : 0); 516 seq_put_decimal_ull(m, ' ', rsslim); 517 seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->start_code : 1) : 0); 518 seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->end_code : 1) : 0); 519 seq_put_decimal_ull(m, ' ', (permitted && mm) ? mm->start_stack : 0); 520 seq_put_decimal_ull(m, ' ', esp); 521 seq_put_decimal_ull(m, ' ', eip); 522 /* The signal information here is obsolete. 523 * It must be decimal for Linux 2.0 compatibility. 524 * Use /proc/#/status for real-time signals. 525 */ 526 seq_put_decimal_ull(m, ' ', task->pending.signal.sig[0] & 0x7fffffffUL); 527 seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL); 528 seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL); 529 seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL); 530 seq_put_decimal_ull(m, ' ', wchan); 531 seq_put_decimal_ull(m, ' ', 0); 532 seq_put_decimal_ull(m, ' ', 0); 533 seq_put_decimal_ll(m, ' ', task->exit_signal); 534 seq_put_decimal_ll(m, ' ', task_cpu(task)); 535 seq_put_decimal_ull(m, ' ', task->rt_priority); 536 seq_put_decimal_ull(m, ' ', task->policy); 537 seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task)); 538 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime)); 539 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime)); 540 541 if (mm && permitted) { 542 seq_put_decimal_ull(m, ' ', mm->start_data); 543 seq_put_decimal_ull(m, ' ', mm->end_data); 544 seq_put_decimal_ull(m, ' ', mm->start_brk); 545 seq_put_decimal_ull(m, ' ', mm->arg_start); 546 seq_put_decimal_ull(m, ' ', mm->arg_end); 547 seq_put_decimal_ull(m, ' ', mm->env_start); 548 seq_put_decimal_ull(m, ' ', mm->env_end); 549 } else 550 seq_printf(m, " 0 0 0 0 0 0 0"); 551 552 if (permitted) 553 seq_put_decimal_ll(m, ' ', task->exit_code); 554 else 555 seq_put_decimal_ll(m, ' ', 0); 556 557 seq_putc(m, '\n'); 558 if (mm) 559 mmput(mm); 560 return 0; 561 } 562 563 int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns, 564 struct pid *pid, struct task_struct *task) 565 { 566 return do_task_stat(m, ns, pid, task, 0); 567 } 568 569 int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns, 570 struct pid *pid, struct task_struct *task) 571 { 572 return do_task_stat(m, ns, pid, task, 1); 573 } 574 575 int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns, 576 struct pid *pid, struct task_struct *task) 577 { 578 unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0; 579 struct mm_struct *mm = get_task_mm(task); 580 581 if (mm) { 582 size = task_statm(mm, &shared, &text, &data, &resident); 583 mmput(mm); 584 } 585 /* 586 * For quick read, open code by putting numbers directly 587 * expected format is 588 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n", 589 * size, resident, shared, text, data); 590 */ 591 seq_put_decimal_ull(m, 0, size); 592 seq_put_decimal_ull(m, ' ', resident); 593 seq_put_decimal_ull(m, ' ', shared); 594 seq_put_decimal_ull(m, ' ', text); 595 seq_put_decimal_ull(m, ' ', 0); 596 seq_put_decimal_ull(m, ' ', data); 597 seq_put_decimal_ull(m, ' ', 0); 598 seq_putc(m, '\n'); 599 600 return 0; 601 } 602 603 #ifdef CONFIG_CHECKPOINT_RESTORE 604 static struct pid * 605 get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos) 606 { 607 struct task_struct *start, *task; 608 struct pid *pid = NULL; 609 610 read_lock(&tasklist_lock); 611 612 start = pid_task(proc_pid(inode), PIDTYPE_PID); 613 if (!start) 614 goto out; 615 616 /* 617 * Lets try to continue searching first, this gives 618 * us significant speedup on children-rich processes. 619 */ 620 if (pid_prev) { 621 task = pid_task(pid_prev, PIDTYPE_PID); 622 if (task && task->real_parent == start && 623 !(list_empty(&task->sibling))) { 624 if (list_is_last(&task->sibling, &start->children)) 625 goto out; 626 task = list_first_entry(&task->sibling, 627 struct task_struct, sibling); 628 pid = get_pid(task_pid(task)); 629 goto out; 630 } 631 } 632 633 /* 634 * Slow search case. 635 * 636 * We might miss some children here if children 637 * are exited while we were not holding the lock, 638 * but it was never promised to be accurate that 639 * much. 640 * 641 * "Just suppose that the parent sleeps, but N children 642 * exit after we printed their tids. Now the slow paths 643 * skips N extra children, we miss N tasks." (c) 644 * 645 * So one need to stop or freeze the leader and all 646 * its children to get a precise result. 647 */ 648 list_for_each_entry(task, &start->children, sibling) { 649 if (pos-- == 0) { 650 pid = get_pid(task_pid(task)); 651 break; 652 } 653 } 654 655 out: 656 read_unlock(&tasklist_lock); 657 return pid; 658 } 659 660 static int children_seq_show(struct seq_file *seq, void *v) 661 { 662 struct inode *inode = seq->private; 663 pid_t pid; 664 665 pid = pid_nr_ns(v, inode->i_sb->s_fs_info); 666 return seq_printf(seq, "%d ", pid); 667 } 668 669 static void *children_seq_start(struct seq_file *seq, loff_t *pos) 670 { 671 return get_children_pid(seq->private, NULL, *pos); 672 } 673 674 static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos) 675 { 676 struct pid *pid; 677 678 pid = get_children_pid(seq->private, v, *pos + 1); 679 put_pid(v); 680 681 ++*pos; 682 return pid; 683 } 684 685 static void children_seq_stop(struct seq_file *seq, void *v) 686 { 687 put_pid(v); 688 } 689 690 static const struct seq_operations children_seq_ops = { 691 .start = children_seq_start, 692 .next = children_seq_next, 693 .stop = children_seq_stop, 694 .show = children_seq_show, 695 }; 696 697 static int children_seq_open(struct inode *inode, struct file *file) 698 { 699 struct seq_file *m; 700 int ret; 701 702 ret = seq_open(file, &children_seq_ops); 703 if (ret) 704 return ret; 705 706 m = file->private_data; 707 m->private = inode; 708 709 return ret; 710 } 711 712 int children_seq_release(struct inode *inode, struct file *file) 713 { 714 seq_release(inode, file); 715 return 0; 716 } 717 718 const struct file_operations proc_tid_children_operations = { 719 .open = children_seq_open, 720 .read = seq_read, 721 .llseek = seq_lseek, 722 .release = children_seq_release, 723 }; 724 #endif /* CONFIG_CHECKPOINT_RESTORE */ 725