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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / fs / proc / array.c
blobcbd0f1b324b972b96f036139fcd96bf53a03fb01
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 "Pid:\t%d\n"
187 "PPid:\t%d\n"
188 "TracerPid:\t%d\n"
189 "Uid:\t%d\t%d\t%d\t%d\n"
190 "Gid:\t%d\t%d\t%d\t%d\n",
191 get_task_state(p),
192 task_tgid_nr_ns(p, ns),
193 pid_nr_ns(pid, ns),
194 ppid, tpid,
195 from_kuid_munged(user_ns, cred->uid),
196 from_kuid_munged(user_ns, cred->euid),
197 from_kuid_munged(user_ns, cred->suid),
198 from_kuid_munged(user_ns, cred->fsuid),
199 from_kgid_munged(user_ns, cred->gid),
200 from_kgid_munged(user_ns, cred->egid),
201 from_kgid_munged(user_ns, cred->sgid),
202 from_kgid_munged(user_ns, cred->fsgid));
203
204 task_lock(p);
205 if (p->files)
206 fdt = files_fdtable(p->files);
207 seq_printf(m,
208 "FDSize:\t%d\n"
209 "Groups:\t",
210 fdt ? fdt->max_fds : 0);
211 rcu_read_unlock();
212
213 group_info = cred->group_info;
214 task_unlock(p);
215
216 for (g = 0; g < group_info->ngroups; g++)
217 seq_printf(m, "%d ",
218 from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
219 put_cred(cred);
220
221 seq_putc(m, '\n');
222 }
223
224 void render_sigset_t(struct seq_file *m, const char *header,
225 sigset_t *set)
226 {
227 int i;
228
229 seq_puts(m, header);
230
231 i = _NSIG;
232 do {
233 int x = 0;
234
235 i -= 4;
236 if (sigismember(set, i+1)) x |= 1;
237 if (sigismember(set, i+2)) x |= 2;
238 if (sigismember(set, i+3)) x |= 4;
239 if (sigismember(set, i+4)) x |= 8;
240 seq_printf(m, "%x", x);
241 } while (i >= 4);
242
243 seq_putc(m, '\n');
244 }
245
246 static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
247 sigset_t *catch)
248 {
249 struct k_sigaction *k;
250 int i;
251
252 k = p->sighand->action;
253 for (i = 1; i <= _NSIG; ++i, ++k) {
254 if (k->sa.sa_handler == SIG_IGN)
255 sigaddset(ign, i);
256 else if (k->sa.sa_handler != SIG_DFL)
257 sigaddset(catch, i);
258 }
259 }
260
261 static inline void task_sig(struct seq_file *m, struct task_struct *p)
262 {
263 unsigned long flags;
264 sigset_t pending, shpending, blocked, ignored, caught;
265 int num_threads = 0;
266 unsigned long qsize = 0;
267 unsigned long qlim = 0;
268
269 sigemptyset(&pending);
270 sigemptyset(&shpending);
271 sigemptyset(&blocked);
272 sigemptyset(&ignored);
273 sigemptyset(&caught);
274
275 if (lock_task_sighand(p, &flags)) {
276 pending = p->pending.signal;
277 shpending = p->signal->shared_pending.signal;
278 blocked = p->blocked;
279 collect_sigign_sigcatch(p, &ignored, &caught);
280 num_threads = get_nr_threads(p);
281 rcu_read_lock(); /* FIXME: is this correct? */
282 qsize = atomic_read(&__task_cred(p)->user->sigpending);
283 rcu_read_unlock();
284 qlim = task_rlimit(p, RLIMIT_SIGPENDING);
285 unlock_task_sighand(p, &flags);
286 }
287
288 seq_printf(m, "Threads:\t%d\n", num_threads);
289 seq_printf(m, "SigQ:\t%lu/%lu\n", qsize, qlim);
290
291 /* render them all */
292 render_sigset_t(m, "SigPnd:\t", &pending);
293 render_sigset_t(m, "ShdPnd:\t", &shpending);
294 render_sigset_t(m, "SigBlk:\t", &blocked);
295 render_sigset_t(m, "SigIgn:\t", &ignored);
296 render_sigset_t(m, "SigCgt:\t", &caught);
297 }
298
299 static void render_cap_t(struct seq_file *m, const char *header,
300 kernel_cap_t *a)
301 {
302 unsigned __capi;
303
304 seq_puts(m, header);
305 CAP_FOR_EACH_U32(__capi) {
306 seq_printf(m, "%08x",
307 a->cap[(_KERNEL_CAPABILITY_U32S-1) - __capi]);
308 }
309 seq_putc(m, '\n');
310 }
311
312 /* Remove non-existent capabilities */
313 #define NORM_CAPS(v) (v.cap[CAP_TO_INDEX(CAP_LAST_CAP)] &= \
314 CAP_TO_MASK(CAP_LAST_CAP + 1) - 1)
315
316 static inline void task_cap(struct seq_file *m, struct task_struct *p)
317 {
318 const struct cred *cred;
319 kernel_cap_t cap_inheritable, cap_permitted, cap_effective, cap_bset;
320
321 rcu_read_lock();
322 cred = __task_cred(p);
323 cap_inheritable = cred->cap_inheritable;
324 cap_permitted = cred->cap_permitted;
325 cap_effective = cred->cap_effective;
326 cap_bset = cred->cap_bset;
327 rcu_read_unlock();
328
329 NORM_CAPS(cap_inheritable);
330 NORM_CAPS(cap_permitted);
331 NORM_CAPS(cap_effective);
332 NORM_CAPS(cap_bset);
333
334 render_cap_t(m, "CapInh:\t", &cap_inheritable);
335 render_cap_t(m, "CapPrm:\t", &cap_permitted);
336 render_cap_t(m, "CapEff:\t", &cap_effective);
337 render_cap_t(m, "CapBnd:\t", &cap_bset);
338 }
339
340 static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
341 {
342 #ifdef CONFIG_SECCOMP
343 seq_printf(m, "Seccomp:\t%d\n", p->seccomp.mode);
344 #endif
345 }
346
347 static inline void task_context_switch_counts(struct seq_file *m,
348 struct task_struct *p)
349 {
350 seq_printf(m, "voluntary_ctxt_switches:\t%lu\n"
351 "nonvoluntary_ctxt_switches:\t%lu\n",
352 p->nvcsw,
353 p->nivcsw);
354 }
355
356 static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
357 {
358 seq_puts(m, "Cpus_allowed:\t");
359 seq_cpumask(m, &task->cpus_allowed);
360 seq_putc(m, '\n');
361 seq_puts(m, "Cpus_allowed_list:\t");
362 seq_cpumask_list(m, &task->cpus_allowed);
363 seq_putc(m, '\n');
364 }
365
366 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
367 struct pid *pid, struct task_struct *task)
368 {
369 struct mm_struct *mm = get_task_mm(task);
370
371 task_name(m, task);
372 task_state(m, ns, pid, task);
373
374 if (mm) {
375 task_mem(m, mm);
376 mmput(mm);
377 }
378 task_sig(m, task);
379 task_cap(m, task);
380 task_seccomp(m, task);
381 task_cpus_allowed(m, task);
382 cpuset_task_status_allowed(m, task);
383 task_context_switch_counts(m, task);
384 return 0;
385 }
386
387 static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
388 struct pid *pid, struct task_struct *task, int whole)
389 {
390 unsigned long vsize, eip, esp, wchan = ~0UL;
391 int priority, nice;
392 int tty_pgrp = -1, tty_nr = 0;
393 sigset_t sigign, sigcatch;
394 char state;
395 pid_t ppid = 0, pgid = -1, sid = -1;
396 int num_threads = 0;
397 int permitted;
398 struct mm_struct *mm;
399 unsigned long long start_time;
400 unsigned long cmin_flt = 0, cmaj_flt = 0;
401 unsigned long min_flt = 0, maj_flt = 0;
402 cputime_t cutime, cstime, utime, stime;
403 cputime_t cgtime, gtime;
404 unsigned long rsslim = 0;
405 char tcomm[sizeof(task->comm)];
406 unsigned long flags;
407
408 state = *get_task_state(task);
409 vsize = eip = esp = 0;
410 permitted = ptrace_may_access(task, PTRACE_MODE_READ | PTRACE_MODE_NOAUDIT);
411 mm = get_task_mm(task);
412 if (mm) {
413 vsize = task_vsize(mm);
414 if (permitted) {
415 eip = KSTK_EIP(task);
416 esp = KSTK_ESP(task);
417 }
418 }
419
420 get_task_comm(tcomm, task);
421
422 sigemptyset(&sigign);
423 sigemptyset(&sigcatch);
424 cutime = cstime = utime = stime = 0;
425 cgtime = gtime = 0;
426
427 if (lock_task_sighand(task, &flags)) {
428 struct signal_struct *sig = task->signal;
429
430 if (sig->tty) {
431 struct pid *pgrp = tty_get_pgrp(sig->tty);
432 tty_pgrp = pid_nr_ns(pgrp, ns);
433 put_pid(pgrp);
434 tty_nr = new_encode_dev(tty_devnum(sig->tty));
435 }
436
437 num_threads = get_nr_threads(task);
438 collect_sigign_sigcatch(task, &sigign, &sigcatch);
439
440 cmin_flt = sig->cmin_flt;
441 cmaj_flt = sig->cmaj_flt;
442 cutime = sig->cutime;
443 cstime = sig->cstime;
444 cgtime = sig->cgtime;
445 rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
446
447 /* add up live thread stats at the group level */
448 if (whole) {
449 struct task_struct *t = task;
450 do {
451 min_flt += t->min_flt;
452 maj_flt += t->maj_flt;
453 gtime += task_gtime(t);
454 t = next_thread(t);
455 } while (t != task);
456
457 min_flt += sig->min_flt;
458 maj_flt += sig->maj_flt;
459 thread_group_cputime_adjusted(task, &utime, &stime);
460 gtime += sig->gtime;
461 }
462
463 sid = task_session_nr_ns(task, ns);
464 ppid = task_tgid_nr_ns(task->real_parent, ns);
465 pgid = task_pgrp_nr_ns(task, ns);
466
467 unlock_task_sighand(task, &flags);
468 }
469
470 if (permitted && (!whole || num_threads < 2))
471 wchan = get_wchan(task);
472 if (!whole) {
473 min_flt = task->min_flt;
474 maj_flt = task->maj_flt;
475 task_cputime_adjusted(task, &utime, &stime);
476 gtime = task_gtime(task);
477 }
478
479 /* scale priority and nice values from timeslices to -20..20 */
480 /* to make it look like a "normal" Unix priority/nice value */
481 priority = task_prio(task);
482 nice = task_nice(task);
483
484 /* Temporary variable needed for gcc-2.96 */
485 /* convert timespec -> nsec*/
486 start_time =
487 (unsigned long long)task->real_start_time.tv_sec * NSEC_PER_SEC
488 + task->real_start_time.tv_nsec;
489 /* convert nsec -> ticks */
490 start_time = nsec_to_clock_t(start_time);
491
492 seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
493 seq_put_decimal_ll(m, ' ', ppid);
494 seq_put_decimal_ll(m, ' ', pgid);
495 seq_put_decimal_ll(m, ' ', sid);
496 seq_put_decimal_ll(m, ' ', tty_nr);
497 seq_put_decimal_ll(m, ' ', tty_pgrp);
498 seq_put_decimal_ull(m, ' ', task->flags);
499 seq_put_decimal_ull(m, ' ', min_flt);
500 seq_put_decimal_ull(m, ' ', cmin_flt);
501 seq_put_decimal_ull(m, ' ', maj_flt);
502 seq_put_decimal_ull(m, ' ', cmaj_flt);
503 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime));
504 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime));
505 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime));
506 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime));
507 seq_put_decimal_ll(m, ' ', priority);
508 seq_put_decimal_ll(m, ' ', nice);
509 seq_put_decimal_ll(m, ' ', num_threads);
510 seq_put_decimal_ull(m, ' ', 0);
511 seq_put_decimal_ull(m, ' ', start_time);
512 seq_put_decimal_ull(m, ' ', vsize);
513 seq_put_decimal_ull(m, ' ', mm ? get_mm_rss(mm) : 0);
514 seq_put_decimal_ull(m, ' ', rsslim);
515 seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->start_code : 1) : 0);
516 seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->end_code : 1) : 0);
517 seq_put_decimal_ull(m, ' ', (permitted && mm) ? mm->start_stack : 0);
518 seq_put_decimal_ull(m, ' ', esp);
519 seq_put_decimal_ull(m, ' ', eip);
520 /* The signal information here is obsolete.
521 * It must be decimal for Linux 2.0 compatibility.
522 * Use /proc/#/status for real-time signals.
523 */
524 seq_put_decimal_ull(m, ' ', task->pending.signal.sig[0] & 0x7fffffffUL);
525 seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL);
526 seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL);
527 seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL);
528 seq_put_decimal_ull(m, ' ', wchan);
529 seq_put_decimal_ull(m, ' ', 0);
530 seq_put_decimal_ull(m, ' ', 0);
531 seq_put_decimal_ll(m, ' ', task->exit_signal);
532 seq_put_decimal_ll(m, ' ', task_cpu(task));
533 seq_put_decimal_ull(m, ' ', task->rt_priority);
534 seq_put_decimal_ull(m, ' ', task->policy);
535 seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task));
536 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime));
537 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime));
538
539 if (mm && permitted) {
540 seq_put_decimal_ull(m, ' ', mm->start_data);
541 seq_put_decimal_ull(m, ' ', mm->end_data);
542 seq_put_decimal_ull(m, ' ', mm->start_brk);
543 seq_put_decimal_ull(m, ' ', mm->arg_start);
544 seq_put_decimal_ull(m, ' ', mm->arg_end);
545 seq_put_decimal_ull(m, ' ', mm->env_start);
546 seq_put_decimal_ull(m, ' ', mm->env_end);
547 } else
548 seq_printf(m, " 0 0 0 0 0 0 0");
549
550 if (permitted)
551 seq_put_decimal_ll(m, ' ', task->exit_code);
552 else
553 seq_put_decimal_ll(m, ' ', 0);
554
555 seq_putc(m, '\n');
556 if (mm)
557 mmput(mm);
558 return 0;
559 }
560
561 int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
562 struct pid *pid, struct task_struct *task)
563 {
564 return do_task_stat(m, ns, pid, task, 0);
565 }
566
567 int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
568 struct pid *pid, struct task_struct *task)
569 {
570 return do_task_stat(m, ns, pid, task, 1);
571 }
572
573 int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
574 struct pid *pid, struct task_struct *task)
575 {
576 unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0;
577 struct mm_struct *mm = get_task_mm(task);
578
579 if (mm) {
580 size = task_statm(mm, &shared, &text, &data, &resident);
581 mmput(mm);
582 }
583 /*
584 * For quick read, open code by putting numbers directly
585 * expected format is
586 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
587 * size, resident, shared, text, data);
588 */
589 seq_put_decimal_ull(m, 0, size);
590 seq_put_decimal_ull(m, ' ', resident);
591 seq_put_decimal_ull(m, ' ', shared);
592 seq_put_decimal_ull(m, ' ', text);
593 seq_put_decimal_ull(m, ' ', 0);
594 seq_put_decimal_ull(m, ' ', data);
595 seq_put_decimal_ull(m, ' ', 0);
596 seq_putc(m, '\n');
597
598 return 0;
599 }
600
601 #ifdef CONFIG_CHECKPOINT_RESTORE
602 static struct pid *
603 get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
604 {
605 struct task_struct *start, *task;
606 struct pid *pid = NULL;
607
608 read_lock(&tasklist_lock);
609
610 start = pid_task(proc_pid(inode), PIDTYPE_PID);
611 if (!start)
612 goto out;
613
614 /*
615 * Lets try to continue searching first, this gives
616 * us significant speedup on children-rich processes.
617 */
618 if (pid_prev) {
619 task = pid_task(pid_prev, PIDTYPE_PID);
620 if (task && task->real_parent == start &&
621 !(list_empty(&task->sibling))) {
622 if (list_is_last(&task->sibling, &start->children))
623 goto out;
624 task = list_first_entry(&task->sibling,
625 struct task_struct, sibling);
626 pid = get_pid(task_pid(task));
627 goto out;
628 }
629 }
630
631 /*
632 * Slow search case.
633 *
634 * We might miss some children here if children
635 * are exited while we were not holding the lock,
636 * but it was never promised to be accurate that
637 * much.
638 *
639 * "Just suppose that the parent sleeps, but N children
640 * exit after we printed their tids. Now the slow paths
641 * skips N extra children, we miss N tasks." (c)
642 *
643 * So one need to stop or freeze the leader and all
644 * its children to get a precise result.
645 */
646 list_for_each_entry(task, &start->children, sibling) {
647 if (pos-- == 0) {
648 pid = get_pid(task_pid(task));
649 break;
650 }
651 }
652
653 out:
654 read_unlock(&tasklist_lock);
655 return pid;
656 }
657
658 static int children_seq_show(struct seq_file *seq, void *v)
659 {
660 struct inode *inode = seq->private;
661 pid_t pid;
662
663 pid = pid_nr_ns(v, inode->i_sb->s_fs_info);
664 return seq_printf(seq, "%d ", pid);
665 }
666
667 static void *children_seq_start(struct seq_file *seq, loff_t *pos)
668 {
669 return get_children_pid(seq->private, NULL, *pos);
670 }
671
672 static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
673 {
674 struct pid *pid;
675
676 pid = get_children_pid(seq->private, v, *pos + 1);
677 put_pid(v);
678
679 ++*pos;
680 return pid;
681 }
682
683 static void children_seq_stop(struct seq_file *seq, void *v)
684 {
685 put_pid(v);
686 }
687
688 static const struct seq_operations children_seq_ops = {
689 .start = children_seq_start,
690 .next = children_seq_next,
691 .stop = children_seq_stop,
692 .show = children_seq_show,
693 };
694
695 static int children_seq_open(struct inode *inode, struct file *file)
696 {
697 struct seq_file *m;
698 int ret;
699
700 ret = seq_open(file, &children_seq_ops);
701 if (ret)
702 return ret;
703
704 m = file->private_data;
705 m->private = inode;
706
707 return ret;
708 }
709
710 int children_seq_release(struct inode *inode, struct file *file)
711 {
712 seq_release(inode, file);
713 return 0;
714 }
715
716 const struct file_operations proc_tid_children_operations = {
717 .open = children_seq_open,
718 .read = seq_read,
719 .llseek = seq_lseek,
720 .release = children_seq_release,
721 };
722 #endif /* CONFIG_CHECKPOINT_RESTORE */
Linus' kernel tree