Merge tag 'v3.10.55' into update
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / proc / array.c
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 = 0, tpid = 0;
172 struct task_struct *leader = NULL;
173
174 rcu_read_lock();
175 if (pid_alive(p)) {
176 struct task_struct *tracer = ptrace_parent(p);
177 if (tracer)
178 tpid = task_pid_nr_ns(tracer, ns);
179 ppid = task_tgid_nr_ns(rcu_dereference(p->real_parent), ns);
180 leader = p->group_leader;
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 leader ? task_pid_nr_ns(leader, ns) : 0,
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[CAP_LAST_U32 - __capi]);
308 }
309 seq_putc(m, '\n');
310 }
311
312 static inline void task_cap(struct seq_file *m, struct task_struct *p)
313 {
314 const struct cred *cred;
315 kernel_cap_t cap_inheritable, cap_permitted, cap_effective, cap_bset;
316
317 rcu_read_lock();
318 cred = __task_cred(p);
319 cap_inheritable = cred->cap_inheritable;
320 cap_permitted = cred->cap_permitted;
321 cap_effective = cred->cap_effective;
322 cap_bset = cred->cap_bset;
323 rcu_read_unlock();
324
325 render_cap_t(m, "CapInh:\t", &cap_inheritable);
326 render_cap_t(m, "CapPrm:\t", &cap_permitted);
327 render_cap_t(m, "CapEff:\t", &cap_effective);
328 render_cap_t(m, "CapBnd:\t", &cap_bset);
329 }
330
331 static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
332 {
333 #ifdef CONFIG_SECCOMP
334 seq_printf(m, "Seccomp:\t%d\n", p->seccomp.mode);
335 #endif
336 }
337
338 static inline void task_context_switch_counts(struct seq_file *m,
339 struct task_struct *p)
340 {
341 seq_printf(m, "voluntary_ctxt_switches:\t%lu\n"
342 "nonvoluntary_ctxt_switches:\t%lu\n",
343 p->nvcsw,
344 p->nivcsw);
345 }
346
347 static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
348 {
349 seq_puts(m, "Cpus_allowed:\t");
350 seq_cpumask(m, &task->cpus_allowed);
351 seq_putc(m, '\n');
352 seq_puts(m, "Cpus_allowed_list:\t");
353 seq_cpumask_list(m, &task->cpus_allowed);
354 seq_putc(m, '\n');
355 }
356
357 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
358 struct pid *pid, struct task_struct *task)
359 {
360 struct mm_struct *mm = get_task_mm(task);
361
362 task_name(m, task);
363 task_state(m, ns, pid, task);
364
365 if (mm) {
366 task_mem(m, mm);
367 mmput(mm);
368 }
369 task_sig(m, task);
370 task_cap(m, task);
371 task_seccomp(m, task);
372 task_cpus_allowed(m, task);
373 cpuset_task_status_allowed(m, task);
374 task_context_switch_counts(m, task);
375 return 0;
376 }
377
378 static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
379 struct pid *pid, struct task_struct *task, int whole)
380 {
381 unsigned long vsize, eip, esp, wchan = ~0UL;
382 int priority, nice;
383 int tty_pgrp = -1, tty_nr = 0;
384 sigset_t sigign, sigcatch;
385 char state;
386 pid_t ppid = 0, pgid = -1, sid = -1;
387 int num_threads = 0;
388 int permitted;
389 struct mm_struct *mm;
390 unsigned long long start_time;
391 unsigned long cmin_flt = 0, cmaj_flt = 0;
392 unsigned long min_flt = 0, maj_flt = 0;
393 cputime_t cutime, cstime, utime, stime;
394 cputime_t cgtime, gtime;
395 unsigned long rsslim = 0;
396 char tcomm[sizeof(task->comm)];
397 unsigned long flags;
398
399 state = *get_task_state(task);
400 vsize = eip = esp = 0;
401 permitted = ptrace_may_access(task, PTRACE_MODE_READ | PTRACE_MODE_NOAUDIT);
402 mm = get_task_mm(task);
403 if (mm) {
404 vsize = task_vsize(mm);
405 if (permitted) {
406 eip = KSTK_EIP(task);
407 esp = KSTK_ESP(task);
408 }
409 }
410
411 get_task_comm(tcomm, task);
412
413 sigemptyset(&sigign);
414 sigemptyset(&sigcatch);
415 cutime = cstime = utime = stime = 0;
416 cgtime = gtime = 0;
417
418 if (lock_task_sighand(task, &flags)) {
419 struct signal_struct *sig = task->signal;
420
421 if (sig->tty) {
422 struct pid *pgrp = tty_get_pgrp(sig->tty);
423 tty_pgrp = pid_nr_ns(pgrp, ns);
424 put_pid(pgrp);
425 tty_nr = new_encode_dev(tty_devnum(sig->tty));
426 }
427
428 num_threads = get_nr_threads(task);
429 collect_sigign_sigcatch(task, &sigign, &sigcatch);
430
431 cmin_flt = sig->cmin_flt;
432 cmaj_flt = sig->cmaj_flt;
433 cutime = sig->cutime;
434 cstime = sig->cstime;
435 cgtime = sig->cgtime;
436 rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
437
438 /* add up live thread stats at the group level */
439 if (whole) {
440 struct task_struct *t = task;
441 do {
442 min_flt += t->min_flt;
443 maj_flt += t->maj_flt;
444 gtime += task_gtime(t);
445 t = next_thread(t);
446 } while (t != task);
447
448 min_flt += sig->min_flt;
449 maj_flt += sig->maj_flt;
450 thread_group_cputime_adjusted(task, &utime, &stime);
451 gtime += sig->gtime;
452 }
453
454 sid = task_session_nr_ns(task, ns);
455 ppid = task_tgid_nr_ns(task->real_parent, ns);
456 pgid = task_pgrp_nr_ns(task, ns);
457
458 unlock_task_sighand(task, &flags);
459 }
460
461 if (permitted && (!whole || num_threads < 2))
462 wchan = get_wchan(task);
463 if (!whole) {
464 min_flt = task->min_flt;
465 maj_flt = task->maj_flt;
466 task_cputime_adjusted(task, &utime, &stime);
467 gtime = task_gtime(task);
468 }
469
470 /* scale priority and nice values from timeslices to -20..20 */
471 /* to make it look like a "normal" Unix priority/nice value */
472 priority = task_prio(task);
473 nice = task_nice(task);
474
475 /* Temporary variable needed for gcc-2.96 */
476 /* convert timespec -> nsec*/
477 start_time =
478 (unsigned long long)task->real_start_time.tv_sec * NSEC_PER_SEC
479 + task->real_start_time.tv_nsec;
480 /* convert nsec -> ticks */
481 start_time = nsec_to_clock_t(start_time);
482
483 seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
484 seq_put_decimal_ll(m, ' ', ppid);
485 seq_put_decimal_ll(m, ' ', pgid);
486 seq_put_decimal_ll(m, ' ', sid);
487 seq_put_decimal_ll(m, ' ', tty_nr);
488 seq_put_decimal_ll(m, ' ', tty_pgrp);
489 seq_put_decimal_ull(m, ' ', task->flags);
490 seq_put_decimal_ull(m, ' ', min_flt);
491 seq_put_decimal_ull(m, ' ', cmin_flt);
492 seq_put_decimal_ull(m, ' ', maj_flt);
493 seq_put_decimal_ull(m, ' ', cmaj_flt);
494 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime));
495 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime));
496 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime));
497 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime));
498 seq_put_decimal_ll(m, ' ', priority);
499 seq_put_decimal_ll(m, ' ', nice);
500 seq_put_decimal_ll(m, ' ', num_threads);
501 seq_put_decimal_ull(m, ' ', 0);
502 seq_put_decimal_ull(m, ' ', start_time);
503 seq_put_decimal_ull(m, ' ', vsize);
504 seq_put_decimal_ull(m, ' ', mm ? get_mm_rss(mm) : 0);
505 seq_put_decimal_ull(m, ' ', rsslim);
506 seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->start_code : 1) : 0);
507 seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->end_code : 1) : 0);
508 seq_put_decimal_ull(m, ' ', (permitted && mm) ? mm->start_stack : 0);
509 seq_put_decimal_ull(m, ' ', esp);
510 seq_put_decimal_ull(m, ' ', eip);
511 /* The signal information here is obsolete.
512 * It must be decimal for Linux 2.0 compatibility.
513 * Use /proc/#/status for real-time signals.
514 */
515 seq_put_decimal_ull(m, ' ', task->pending.signal.sig[0] & 0x7fffffffUL);
516 seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL);
517 seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL);
518 seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL);
519 seq_put_decimal_ull(m, ' ', wchan);
520 seq_put_decimal_ull(m, ' ', 0);
521 seq_put_decimal_ull(m, ' ', 0);
522 seq_put_decimal_ll(m, ' ', task->exit_signal);
523 seq_put_decimal_ll(m, ' ', task_cpu(task));
524 seq_put_decimal_ull(m, ' ', task->rt_priority);
525 seq_put_decimal_ull(m, ' ', task->policy);
526 seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task));
527 seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime));
528 seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime));
529
530 if (mm && permitted) {
531 seq_put_decimal_ull(m, ' ', mm->start_data);
532 seq_put_decimal_ull(m, ' ', mm->end_data);
533 seq_put_decimal_ull(m, ' ', mm->start_brk);
534 seq_put_decimal_ull(m, ' ', mm->arg_start);
535 seq_put_decimal_ull(m, ' ', mm->arg_end);
536 seq_put_decimal_ull(m, ' ', mm->env_start);
537 seq_put_decimal_ull(m, ' ', mm->env_end);
538 } else
539 seq_printf(m, " 0 0 0 0 0 0 0");
540
541 if (permitted)
542 seq_put_decimal_ll(m, ' ', task->exit_code);
543 else
544 seq_put_decimal_ll(m, ' ', 0);
545
546 seq_putc(m, '\n');
547 if (mm)
548 mmput(mm);
549 return 0;
550 }
551
552 int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
553 struct pid *pid, struct task_struct *task)
554 {
555 return do_task_stat(m, ns, pid, task, 0);
556 }
557
558 int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
559 struct pid *pid, struct task_struct *task)
560 {
561 return do_task_stat(m, ns, pid, task, 1);
562 }
563
564 int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
565 struct pid *pid, struct task_struct *task)
566 {
567 unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0;
568 struct mm_struct *mm = get_task_mm(task);
569
570 if (mm) {
571 size = task_statm(mm, &shared, &text, &data, &resident);
572 mmput(mm);
573 }
574 /*
575 * For quick read, open code by putting numbers directly
576 * expected format is
577 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
578 * size, resident, shared, text, data);
579 */
580 seq_put_decimal_ull(m, 0, size);
581 seq_put_decimal_ull(m, ' ', resident);
582 seq_put_decimal_ull(m, ' ', shared);
583 seq_put_decimal_ull(m, ' ', text);
584 seq_put_decimal_ull(m, ' ', 0);
585 seq_put_decimal_ull(m, ' ', data);
586 seq_put_decimal_ull(m, ' ', 0);
587 seq_putc(m, '\n');
588
589 return 0;
590 }
591
592 #ifdef CONFIG_CHECKPOINT_RESTORE
593 static struct pid *
594 get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
595 {
596 struct task_struct *start, *task;
597 struct pid *pid = NULL;
598
599 read_lock(&tasklist_lock);
600
601 start = pid_task(proc_pid(inode), PIDTYPE_PID);
602 if (!start)
603 goto out;
604
605 /*
606 * Lets try to continue searching first, this gives
607 * us significant speedup on children-rich processes.
608 */
609 if (pid_prev) {
610 task = pid_task(pid_prev, PIDTYPE_PID);
611 if (task && task->real_parent == start &&
612 !(list_empty(&task->sibling))) {
613 if (list_is_last(&task->sibling, &start->children))
614 goto out;
615 task = list_first_entry(&task->sibling,
616 struct task_struct, sibling);
617 pid = get_pid(task_pid(task));
618 goto out;
619 }
620 }
621
622 /*
623 * Slow search case.
624 *
625 * We might miss some children here if children
626 * are exited while we were not holding the lock,
627 * but it was never promised to be accurate that
628 * much.
629 *
630 * "Just suppose that the parent sleeps, but N children
631 * exit after we printed their tids. Now the slow paths
632 * skips N extra children, we miss N tasks." (c)
633 *
634 * So one need to stop or freeze the leader and all
635 * its children to get a precise result.
636 */
637 list_for_each_entry(task, &start->children, sibling) {
638 if (pos-- == 0) {
639 pid = get_pid(task_pid(task));
640 break;
641 }
642 }
643
644 out:
645 read_unlock(&tasklist_lock);
646 return pid;
647 }
648
649 static int children_seq_show(struct seq_file *seq, void *v)
650 {
651 struct inode *inode = seq->private;
652 pid_t pid;
653
654 pid = pid_nr_ns(v, inode->i_sb->s_fs_info);
655 return seq_printf(seq, "%d ", pid);
656 }
657
658 static void *children_seq_start(struct seq_file *seq, loff_t *pos)
659 {
660 return get_children_pid(seq->private, NULL, *pos);
661 }
662
663 static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
664 {
665 struct pid *pid;
666
667 pid = get_children_pid(seq->private, v, *pos + 1);
668 put_pid(v);
669
670 ++*pos;
671 return pid;
672 }
673
674 static void children_seq_stop(struct seq_file *seq, void *v)
675 {
676 put_pid(v);
677 }
678
679 static const struct seq_operations children_seq_ops = {
680 .start = children_seq_start,
681 .next = children_seq_next,
682 .stop = children_seq_stop,
683 .show = children_seq_show,
684 };
685
686 static int children_seq_open(struct inode *inode, struct file *file)
687 {
688 struct seq_file *m;
689 int ret;
690
691 ret = seq_open(file, &children_seq_ops);
692 if (ret)
693 return ret;
694
695 m = file->private_data;
696 m->private = inode;
697
698 return ret;
699 }
700
701 int children_seq_release(struct inode *inode, struct file *file)
702 {
703 seq_release(inode, file);
704 return 0;
705 }
706
707 const struct file_operations proc_tid_children_operations = {
708 .open = children_seq_open,
709 .read = seq_read,
710 .llseek = seq_lseek,
711 .release = children_seq_release,
712 };
713 #endif /* CONFIG_CHECKPOINT_RESTORE */