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/string_helpers.h>
85#include <linux/user_namespace.h>
86
87#include <asm/pgtable.h>
88#include <asm/processor.h>
89#include "internal.h"
90
91static inline void task_name(struct seq_file *m, struct task_struct *p)
92{
93	char *buf;
94	char tcomm[sizeof(p->comm)];
95
96	get_task_comm(tcomm, p);
97
98	seq_puts(m, "Name:\t");
99	buf = m->buf + m->count;
100
101	/* Ignore error for now */
102	buf += string_escape_str(tcomm, buf, m->size - m->count,
103				 ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
104
105	m->count = buf - m->buf;
106	seq_putc(m, '\n');
107}
108
109/*
110 * The task state array is a strange "bitmap" of
111 * reasons to sleep. Thus "running" is zero, and
112 * you can test for combinations of others with
113 * simple bit tests.
114 */
115static const char * const task_state_array[] = {
116	"R (running)",		/*   0 */
117	"S (sleeping)",		/*   1 */
118	"D (disk sleep)",	/*   2 */
119	"T (stopped)",		/*   4 */
120	"t (tracing stop)",	/*   8 */
121	"X (dead)",		/*  16 */
122	"Z (zombie)",		/*  32 */
123};
124
125static inline const char *get_task_state(struct task_struct *tsk)
126{
127	unsigned int state = (tsk->state | tsk->exit_state) & TASK_REPORT;
128
129	BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array)-1);
130
131	return task_state_array[fls(state)];
132}
133
134static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
135				struct pid *pid, struct task_struct *p)
136{
137	struct user_namespace *user_ns = seq_user_ns(m);
138	struct group_info *group_info;
139	int g;
140	struct task_struct *tracer;
141	const struct cred *cred;
142	pid_t ppid, tpid = 0, tgid, ngid;
143	unsigned int max_fds = 0;
144
145	rcu_read_lock();
146	ppid = pid_alive(p) ?
147		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
148
149	tracer = ptrace_parent(p);
150	if (tracer)
151		tpid = task_pid_nr_ns(tracer, ns);
152
153	tgid = task_tgid_nr_ns(p, ns);
154	ngid = task_numa_group_id(p);
155	cred = get_task_cred(p);
156
157	task_lock(p);
158	if (p->files)
159		max_fds = files_fdtable(p->files)->max_fds;
160	task_unlock(p);
161	rcu_read_unlock();
162
163	seq_printf(m,
164		"State:\t%s\n"
165		"Tgid:\t%d\n"
166		"Ngid:\t%d\n"
167		"Pid:\t%d\n"
168		"PPid:\t%d\n"
169		"TracerPid:\t%d\n"
170		"Uid:\t%d\t%d\t%d\t%d\n"
171		"Gid:\t%d\t%d\t%d\t%d\n"
172		"FDSize:\t%d\nGroups:\t",
173		get_task_state(p),
174		tgid, ngid, pid_nr_ns(pid, ns), ppid, tpid,
175		from_kuid_munged(user_ns, cred->uid),
176		from_kuid_munged(user_ns, cred->euid),
177		from_kuid_munged(user_ns, cred->suid),
178		from_kuid_munged(user_ns, cred->fsuid),
179		from_kgid_munged(user_ns, cred->gid),
180		from_kgid_munged(user_ns, cred->egid),
181		from_kgid_munged(user_ns, cred->sgid),
182		from_kgid_munged(user_ns, cred->fsgid),
183		max_fds);
184
185	group_info = cred->group_info;
186	for (g = 0; g < group_info->ngroups; g++)
187		seq_printf(m, "%d ",
188			   from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
189	put_cred(cred);
190
191#ifdef CONFIG_PID_NS
192	seq_puts(m, "\nNStgid:");
193	for (g = ns->level; g <= pid->level; g++)
194		seq_printf(m, "\t%d",
195			task_tgid_nr_ns(p, pid->numbers[g].ns));
196	seq_puts(m, "\nNSpid:");
197	for (g = ns->level; g <= pid->level; g++)
198		seq_printf(m, "\t%d",
199			task_pid_nr_ns(p, pid->numbers[g].ns));
200	seq_puts(m, "\nNSpgid:");
201	for (g = ns->level; g <= pid->level; g++)
202		seq_printf(m, "\t%d",
203			task_pgrp_nr_ns(p, pid->numbers[g].ns));
204	seq_puts(m, "\nNSsid:");
205	for (g = ns->level; g <= pid->level; g++)
206		seq_printf(m, "\t%d",
207			task_session_nr_ns(p, pid->numbers[g].ns));
208#endif
209	seq_putc(m, '\n');
210}
211
212void render_sigset_t(struct seq_file *m, const char *header,
213				sigset_t *set)
214{
215	int i;
216
217	seq_puts(m, header);
218
219	i = _NSIG;
220	do {
221		int x = 0;
222
223		i -= 4;
224		if (sigismember(set, i+1)) x |= 1;
225		if (sigismember(set, i+2)) x |= 2;
226		if (sigismember(set, i+3)) x |= 4;
227		if (sigismember(set, i+4)) x |= 8;
228		seq_printf(m, "%x", x);
229	} while (i >= 4);
230
231	seq_putc(m, '\n');
232}
233
234static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
235				    sigset_t *catch)
236{
237	struct k_sigaction *k;
238	int i;
239
240	k = p->sighand->action;
241	for (i = 1; i <= _NSIG; ++i, ++k) {
242		if (k->sa.sa_handler == SIG_IGN)
243			sigaddset(ign, i);
244		else if (k->sa.sa_handler != SIG_DFL)
245			sigaddset(catch, i);
246	}
247}
248
249static inline void task_sig(struct seq_file *m, struct task_struct *p)
250{
251	unsigned long flags;
252	sigset_t pending, shpending, blocked, ignored, caught;
253	int num_threads = 0;
254	unsigned long qsize = 0;
255	unsigned long qlim = 0;
256
257	sigemptyset(&pending);
258	sigemptyset(&shpending);
259	sigemptyset(&blocked);
260	sigemptyset(&ignored);
261	sigemptyset(&caught);
262
263	if (lock_task_sighand(p, &flags)) {
264		pending = p->pending.signal;
265		shpending = p->signal->shared_pending.signal;
266		blocked = p->blocked;
267		collect_sigign_sigcatch(p, &ignored, &caught);
268		num_threads = get_nr_threads(p);
269		rcu_read_lock();  /* FIXME: is this correct? */
270		qsize = atomic_read(&__task_cred(p)->user->sigpending);
271		rcu_read_unlock();
272		qlim = task_rlimit(p, RLIMIT_SIGPENDING);
273		unlock_task_sighand(p, &flags);
274	}
275
276	seq_printf(m, "Threads:\t%d\n", num_threads);
277	seq_printf(m, "SigQ:\t%lu/%lu\n", qsize, qlim);
278
279	/* render them all */
280	render_sigset_t(m, "SigPnd:\t", &pending);
281	render_sigset_t(m, "ShdPnd:\t", &shpending);
282	render_sigset_t(m, "SigBlk:\t", &blocked);
283	render_sigset_t(m, "SigIgn:\t", &ignored);
284	render_sigset_t(m, "SigCgt:\t", &caught);
285}
286
287static void render_cap_t(struct seq_file *m, const char *header,
288			kernel_cap_t *a)
289{
290	unsigned __capi;
291
292	seq_puts(m, header);
293	CAP_FOR_EACH_U32(__capi) {
294		seq_printf(m, "%08x",
295			   a->cap[CAP_LAST_U32 - __capi]);
296	}
297	seq_putc(m, '\n');
298}
299
300static inline void task_cap(struct seq_file *m, struct task_struct *p)
301{
302	const struct cred *cred;
303	kernel_cap_t cap_inheritable, cap_permitted, cap_effective, cap_bset;
304
305	rcu_read_lock();
306	cred = __task_cred(p);
307	cap_inheritable	= cred->cap_inheritable;
308	cap_permitted	= cred->cap_permitted;
309	cap_effective	= cred->cap_effective;
310	cap_bset	= cred->cap_bset;
311	rcu_read_unlock();
312
313	render_cap_t(m, "CapInh:\t", &cap_inheritable);
314	render_cap_t(m, "CapPrm:\t", &cap_permitted);
315	render_cap_t(m, "CapEff:\t", &cap_effective);
316	render_cap_t(m, "CapBnd:\t", &cap_bset);
317}
318
319static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
320{
321#ifdef CONFIG_SECCOMP
322	seq_printf(m, "Seccomp:\t%d\n", p->seccomp.mode);
323#endif
324}
325
326static inline void task_context_switch_counts(struct seq_file *m,
327						struct task_struct *p)
328{
329	seq_printf(m,	"voluntary_ctxt_switches:\t%lu\n"
330			"nonvoluntary_ctxt_switches:\t%lu\n",
331			p->nvcsw,
332			p->nivcsw);
333}
334
335static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
336{
337	seq_printf(m, "Cpus_allowed:\t%*pb\n",
338		   cpumask_pr_args(&task->cpus_allowed));
339	seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
340		   cpumask_pr_args(&task->cpus_allowed));
341}
342
343int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
344			struct pid *pid, struct task_struct *task)
345{
346	struct mm_struct *mm = get_task_mm(task);
347
348	task_name(m, task);
349	task_state(m, ns, pid, task);
350
351	if (mm) {
352		task_mem(m, mm);
353		mmput(mm);
354	}
355	task_sig(m, task);
356	task_cap(m, task);
357	task_seccomp(m, task);
358	task_cpus_allowed(m, task);
359	cpuset_task_status_allowed(m, task);
360	task_context_switch_counts(m, task);
361	return 0;
362}
363
364static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
365			struct pid *pid, struct task_struct *task, int whole)
366{
367	unsigned long vsize, eip, esp, wchan = 0;
368	int priority, nice;
369	int tty_pgrp = -1, tty_nr = 0;
370	sigset_t sigign, sigcatch;
371	char state;
372	pid_t ppid = 0, pgid = -1, sid = -1;
373	int num_threads = 0;
374	int permitted;
375	struct mm_struct *mm;
376	unsigned long long start_time;
377	unsigned long cmin_flt = 0, cmaj_flt = 0;
378	unsigned long  min_flt = 0,  maj_flt = 0;
379	cputime_t cutime, cstime, utime, stime;
380	cputime_t cgtime, gtime;
381	unsigned long rsslim = 0;
382	char tcomm[sizeof(task->comm)];
383	unsigned long flags;
384
385	state = *get_task_state(task);
386	vsize = eip = esp = 0;
387	permitted = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS | PTRACE_MODE_NOAUDIT);
388	mm = get_task_mm(task);
389	if (mm) {
390		vsize = task_vsize(mm);
391		if (permitted) {
392			eip = KSTK_EIP(task);
393			esp = KSTK_ESP(task);
394		}
395	}
396
397	get_task_comm(tcomm, task);
398
399	sigemptyset(&sigign);
400	sigemptyset(&sigcatch);
401	cutime = cstime = utime = stime = 0;
402	cgtime = gtime = 0;
403
404	if (lock_task_sighand(task, &flags)) {
405		struct signal_struct *sig = task->signal;
406
407		if (sig->tty) {
408			struct pid *pgrp = tty_get_pgrp(sig->tty);
409			tty_pgrp = pid_nr_ns(pgrp, ns);
410			put_pid(pgrp);
411			tty_nr = new_encode_dev(tty_devnum(sig->tty));
412		}
413
414		num_threads = get_nr_threads(task);
415		collect_sigign_sigcatch(task, &sigign, &sigcatch);
416
417		cmin_flt = sig->cmin_flt;
418		cmaj_flt = sig->cmaj_flt;
419		cutime = sig->cutime;
420		cstime = sig->cstime;
421		cgtime = sig->cgtime;
422		rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
423
424		/* add up live thread stats at the group level */
425		if (whole) {
426			struct task_struct *t = task;
427			do {
428				min_flt += t->min_flt;
429				maj_flt += t->maj_flt;
430				gtime += task_gtime(t);
431			} while_each_thread(task, t);
432
433			min_flt += sig->min_flt;
434			maj_flt += sig->maj_flt;
435			thread_group_cputime_adjusted(task, &utime, &stime);
436			gtime += sig->gtime;
437		}
438
439		sid = task_session_nr_ns(task, ns);
440		ppid = task_tgid_nr_ns(task->real_parent, ns);
441		pgid = task_pgrp_nr_ns(task, ns);
442
443		unlock_task_sighand(task, &flags);
444	}
445
446	if (permitted && (!whole || num_threads < 2))
447		wchan = get_wchan(task);
448	if (!whole) {
449		min_flt = task->min_flt;
450		maj_flt = task->maj_flt;
451		task_cputime_adjusted(task, &utime, &stime);
452		gtime = task_gtime(task);
453	}
454
455	/* scale priority and nice values from timeslices to -20..20 */
456	/* to make it look like a "normal" Unix priority/nice value  */
457	priority = task_prio(task);
458	nice = task_nice(task);
459
460	/* convert nsec -> ticks */
461	start_time = nsec_to_clock_t(task->real_start_time);
462
463	seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
464	seq_put_decimal_ll(m, ' ', ppid);
465	seq_put_decimal_ll(m, ' ', pgid);
466	seq_put_decimal_ll(m, ' ', sid);
467	seq_put_decimal_ll(m, ' ', tty_nr);
468	seq_put_decimal_ll(m, ' ', tty_pgrp);
469	seq_put_decimal_ull(m, ' ', task->flags);
470	seq_put_decimal_ull(m, ' ', min_flt);
471	seq_put_decimal_ull(m, ' ', cmin_flt);
472	seq_put_decimal_ull(m, ' ', maj_flt);
473	seq_put_decimal_ull(m, ' ', cmaj_flt);
474	seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime));
475	seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime));
476	seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime));
477	seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime));
478	seq_put_decimal_ll(m, ' ', priority);
479	seq_put_decimal_ll(m, ' ', nice);
480	seq_put_decimal_ll(m, ' ', num_threads);
481	seq_put_decimal_ull(m, ' ', 0);
482	seq_put_decimal_ull(m, ' ', start_time);
483	seq_put_decimal_ull(m, ' ', vsize);
484	seq_put_decimal_ull(m, ' ', mm ? get_mm_rss(mm) : 0);
485	seq_put_decimal_ull(m, ' ', rsslim);
486	seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->start_code : 1) : 0);
487	seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->end_code : 1) : 0);
488	seq_put_decimal_ull(m, ' ', (permitted && mm) ? mm->start_stack : 0);
489	seq_put_decimal_ull(m, ' ', esp);
490	seq_put_decimal_ull(m, ' ', eip);
491	/* The signal information here is obsolete.
492	 * It must be decimal for Linux 2.0 compatibility.
493	 * Use /proc/#/status for real-time signals.
494	 */
495	seq_put_decimal_ull(m, ' ', task->pending.signal.sig[0] & 0x7fffffffUL);
496	seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL);
497	seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL);
498	seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL);
499
500	/*
501	 * We used to output the absolute kernel address, but that's an
502	 * information leak - so instead we show a 0/1 flag here, to signal
503	 * to user-space whether there's a wchan field in /proc/PID/wchan.
504	 *
505	 * This works with older implementations of procps as well.
506	 */
507	if (wchan)
508		seq_puts(m, " 1");
509	else
510		seq_puts(m, " 0");
511
512	seq_put_decimal_ull(m, ' ', 0);
513	seq_put_decimal_ull(m, ' ', 0);
514	seq_put_decimal_ll(m, ' ', task->exit_signal);
515	seq_put_decimal_ll(m, ' ', task_cpu(task));
516	seq_put_decimal_ull(m, ' ', task->rt_priority);
517	seq_put_decimal_ull(m, ' ', task->policy);
518	seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task));
519	seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime));
520	seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime));
521
522	if (mm && permitted) {
523		seq_put_decimal_ull(m, ' ', mm->start_data);
524		seq_put_decimal_ull(m, ' ', mm->end_data);
525		seq_put_decimal_ull(m, ' ', mm->start_brk);
526		seq_put_decimal_ull(m, ' ', mm->arg_start);
527		seq_put_decimal_ull(m, ' ', mm->arg_end);
528		seq_put_decimal_ull(m, ' ', mm->env_start);
529		seq_put_decimal_ull(m, ' ', mm->env_end);
530	} else
531		seq_printf(m, " 0 0 0 0 0 0 0");
532
533	if (permitted)
534		seq_put_decimal_ll(m, ' ', task->exit_code);
535	else
536		seq_put_decimal_ll(m, ' ', 0);
537
538	seq_putc(m, '\n');
539	if (mm)
540		mmput(mm);
541	return 0;
542}
543
544int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
545			struct pid *pid, struct task_struct *task)
546{
547	return do_task_stat(m, ns, pid, task, 0);
548}
549
550int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
551			struct pid *pid, struct task_struct *task)
552{
553	return do_task_stat(m, ns, pid, task, 1);
554}
555
556int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
557			struct pid *pid, struct task_struct *task)
558{
559	unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0;
560	struct mm_struct *mm = get_task_mm(task);
561
562	if (mm) {
563		size = task_statm(mm, &shared, &text, &data, &resident);
564		mmput(mm);
565	}
566	/*
567	 * For quick read, open code by putting numbers directly
568	 * expected format is
569	 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
570	 *               size, resident, shared, text, data);
571	 */
572	seq_put_decimal_ull(m, 0, size);
573	seq_put_decimal_ull(m, ' ', resident);
574	seq_put_decimal_ull(m, ' ', shared);
575	seq_put_decimal_ull(m, ' ', text);
576	seq_put_decimal_ull(m, ' ', 0);
577	seq_put_decimal_ull(m, ' ', data);
578	seq_put_decimal_ull(m, ' ', 0);
579	seq_putc(m, '\n');
580
581	return 0;
582}
583
584#ifdef CONFIG_CHECKPOINT_RESTORE
585static struct pid *
586get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
587{
588	struct task_struct *start, *task;
589	struct pid *pid = NULL;
590
591	read_lock(&tasklist_lock);
592
593	start = pid_task(proc_pid(inode), PIDTYPE_PID);
594	if (!start)
595		goto out;
596
597	/*
598	 * Lets try to continue searching first, this gives
599	 * us significant speedup on children-rich processes.
600	 */
601	if (pid_prev) {
602		task = pid_task(pid_prev, PIDTYPE_PID);
603		if (task && task->real_parent == start &&
604		    !(list_empty(&task->sibling))) {
605			if (list_is_last(&task->sibling, &start->children))
606				goto out;
607			task = list_first_entry(&task->sibling,
608						struct task_struct, sibling);
609			pid = get_pid(task_pid(task));
610			goto out;
611		}
612	}
613
614	/*
615	 * Slow search case.
616	 *
617	 * We might miss some children here if children
618	 * are exited while we were not holding the lock,
619	 * but it was never promised to be accurate that
620	 * much.
621	 *
622	 * "Just suppose that the parent sleeps, but N children
623	 *  exit after we printed their tids. Now the slow paths
624	 *  skips N extra children, we miss N tasks." (c)
625	 *
626	 * So one need to stop or freeze the leader and all
627	 * its children to get a precise result.
628	 */
629	list_for_each_entry(task, &start->children, sibling) {
630		if (pos-- == 0) {
631			pid = get_pid(task_pid(task));
632			break;
633		}
634	}
635
636out:
637	read_unlock(&tasklist_lock);
638	return pid;
639}
640
641static int children_seq_show(struct seq_file *seq, void *v)
642{
643	struct inode *inode = seq->private;
644	pid_t pid;
645
646	pid = pid_nr_ns(v, inode->i_sb->s_fs_info);
647	seq_printf(seq, "%d ", pid);
648
649	return 0;
650}
651
652static void *children_seq_start(struct seq_file *seq, loff_t *pos)
653{
654	return get_children_pid(seq->private, NULL, *pos);
655}
656
657static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
658{
659	struct pid *pid;
660
661	pid = get_children_pid(seq->private, v, *pos + 1);
662	put_pid(v);
663
664	++*pos;
665	return pid;
666}
667
668static void children_seq_stop(struct seq_file *seq, void *v)
669{
670	put_pid(v);
671}
672
673static const struct seq_operations children_seq_ops = {
674	.start	= children_seq_start,
675	.next	= children_seq_next,
676	.stop	= children_seq_stop,
677	.show	= children_seq_show,
678};
679
680static int children_seq_open(struct inode *inode, struct file *file)
681{
682	struct seq_file *m;
683	int ret;
684
685	ret = seq_open(file, &children_seq_ops);
686	if (ret)
687		return ret;
688
689	m = file->private_data;
690	m->private = inode;
691
692	return ret;
693}
694
695int children_seq_release(struct inode *inode, struct file *file)
696{
697	seq_release(inode, file);
698	return 0;
699}
700
701const struct file_operations proc_tid_children_operations = {
702	.open    = children_seq_open,
703	.read    = seq_read,
704	.llseek  = seq_lseek,
705	.release = children_seq_release,
706};
707#endif /* CONFIG_CHECKPOINT_RESTORE */
708