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
 90static 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 */
135static 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};
147
148static inline const char *get_task_state(struct task_struct *tsk)
149{
150	unsigned int state = (tsk->state & TASK_REPORT) | tsk->exit_state;
151	const char * const *p = &task_state_array[0];
152
153	BUILD_BUG_ON(1 + ilog2(TASK_STATE_MAX) != ARRAY_SIZE(task_state_array));
154
155	while (state) {
156		p++;
157		state >>= 1;
158	}
159	return *p;
160}
161
162static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
163				struct pid *pid, struct task_struct *p)
164{
165	struct user_namespace *user_ns = current_user_ns();
166	struct group_info *group_info;
167	int g;
168	struct fdtable *fdt = NULL;
169	const struct cred *cred;
170	pid_t ppid, tpid;
171
172	rcu_read_lock();
173	ppid = pid_alive(p) ?
174		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
175	tpid = 0;
176	if (pid_alive(p)) {
177		struct task_struct *tracer = ptrace_parent(p);
178		if (tracer)
179			tpid = task_pid_nr_ns(tracer, ns);
180	}
181	cred = get_task_cred(p);
182	seq_printf(m,
183		"State:\t%s\n"
184		"Tgid:\t%d\n"
185		"Pid:\t%d\n"
186		"PPid:\t%d\n"
187		"TracerPid:\t%d\n"
188		"Uid:\t%d\t%d\t%d\t%d\n"
189		"Gid:\t%d\t%d\t%d\t%d\n",
190		get_task_state(p),
191		task_tgid_nr_ns(p, ns),
192		pid_nr_ns(pid, ns),
193		ppid, tpid,
194		from_kuid_munged(user_ns, cred->uid),
195		from_kuid_munged(user_ns, cred->euid),
196		from_kuid_munged(user_ns, cred->suid),
197		from_kuid_munged(user_ns, cred->fsuid),
198		from_kgid_munged(user_ns, cred->gid),
199		from_kgid_munged(user_ns, cred->egid),
200		from_kgid_munged(user_ns, cred->sgid),
201		from_kgid_munged(user_ns, cred->fsgid));
202
203	task_lock(p);
204	if (p->files)
205		fdt = files_fdtable(p->files);
206	seq_printf(m,
207		"FDSize:\t%d\n"
208		"Groups:\t",
209		fdt ? fdt->max_fds : 0);
210	rcu_read_unlock();
211
212	group_info = cred->group_info;
213	task_unlock(p);
214
215	for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
216		seq_printf(m, "%d ",
217			   from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
218	put_cred(cred);
219
220	seq_putc(m, '\n');
221}
222
223static void render_sigset_t(struct seq_file *m, const char *header,
224				sigset_t *set)
225{
226	int i;
227
228	seq_puts(m, header);
229
230	i = _NSIG;
231	do {
232		int x = 0;
233
234		i -= 4;
235		if (sigismember(set, i+1)) x |= 1;
236		if (sigismember(set, i+2)) x |= 2;
237		if (sigismember(set, i+3)) x |= 4;
238		if (sigismember(set, i+4)) x |= 8;
239		seq_printf(m, "%x", x);
240	} while (i >= 4);
241
242	seq_putc(m, '\n');
243}
244
245static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
246				    sigset_t *catch)
247{
248	struct k_sigaction *k;
249	int i;
250
251	k = p->sighand->action;
252	for (i = 1; i <= _NSIG; ++i, ++k) {
253		if (k->sa.sa_handler == SIG_IGN)
254			sigaddset(ign, i);
255		else if (k->sa.sa_handler != SIG_DFL)
256			sigaddset(catch, i);
257	}
258}
259
260static inline void task_sig(struct seq_file *m, struct task_struct *p)
261{
262	unsigned long flags;
263	sigset_t pending, shpending, blocked, ignored, caught;
264	int num_threads = 0;
265	unsigned long qsize = 0;
266	unsigned long qlim = 0;
267
268	sigemptyset(&pending);
269	sigemptyset(&shpending);
270	sigemptyset(&blocked);
271	sigemptyset(&ignored);
272	sigemptyset(&caught);
273
274	if (lock_task_sighand(p, &flags)) {
275		pending = p->pending.signal;
276		shpending = p->signal->shared_pending.signal;
277		blocked = p->blocked;
278		collect_sigign_sigcatch(p, &ignored, &caught);
279		num_threads = get_nr_threads(p);
280		rcu_read_lock();  /* FIXME: is this correct? */
281		qsize = atomic_read(&__task_cred(p)->user->sigpending);
282		rcu_read_unlock();
283		qlim = task_rlimit(p, RLIMIT_SIGPENDING);
284		unlock_task_sighand(p, &flags);
285	}
286
287	seq_printf(m, "Threads:\t%d\n", num_threads);
288	seq_printf(m, "SigQ:\t%lu/%lu\n", qsize, qlim);
289
290	/* render them all */
291	render_sigset_t(m, "SigPnd:\t", &pending);
292	render_sigset_t(m, "ShdPnd:\t", &shpending);
293	render_sigset_t(m, "SigBlk:\t", &blocked);
294	render_sigset_t(m, "SigIgn:\t", &ignored);
295	render_sigset_t(m, "SigCgt:\t", &caught);
296}
297
298static void render_cap_t(struct seq_file *m, const char *header,
299			kernel_cap_t *a)
300{
301	unsigned __capi;
302
303	seq_puts(m, header);
304	CAP_FOR_EACH_U32(__capi) {
305		seq_printf(m, "%08x",
306			   a->cap[(_KERNEL_CAPABILITY_U32S-1) - __capi]);
307	}
308	seq_putc(m, '\n');
309}
310
311static inline void task_cap(struct seq_file *m, struct task_struct *p)
312{
313	const struct cred *cred;
314	kernel_cap_t cap_inheritable, cap_permitted, cap_effective, cap_bset;
315
316	rcu_read_lock();
317	cred = __task_cred(p);
318	cap_inheritable	= cred->cap_inheritable;
319	cap_permitted	= cred->cap_permitted;
320	cap_effective	= cred->cap_effective;
321	cap_bset	= cred->cap_bset;
322	rcu_read_unlock();
323
324	render_cap_t(m, "CapInh:\t", &cap_inheritable);
325	render_cap_t(m, "CapPrm:\t", &cap_permitted);
326	render_cap_t(m, "CapEff:\t", &cap_effective);
327	render_cap_t(m, "CapBnd:\t", &cap_bset);
328}
329
330static inline void task_context_switch_counts(struct seq_file *m,
331						struct task_struct *p)
332{
333	seq_printf(m,	"voluntary_ctxt_switches:\t%lu\n"
334			"nonvoluntary_ctxt_switches:\t%lu\n",
335			p->nvcsw,
336			p->nivcsw);
337}
338
339static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
340{
341	seq_puts(m, "Cpus_allowed:\t");
342	seq_cpumask(m, &task->cpus_allowed);
343	seq_putc(m, '\n');
344	seq_puts(m, "Cpus_allowed_list:\t");
345	seq_cpumask_list(m, &task->cpus_allowed);
346	seq_putc(m, '\n');
347}
348
349int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
350			struct pid *pid, struct task_struct *task)
351{
352	struct mm_struct *mm = get_task_mm(task);
353
354	task_name(m, task);
355	task_state(m, ns, pid, task);
356
357	if (mm) {
358		task_mem(m, mm);
359		mmput(mm);
360	}
361	task_sig(m, task);
362	task_cap(m, task);
363	task_cpus_allowed(m, task);
364	cpuset_task_status_allowed(m, task);
365	task_context_switch_counts(m, task);
366	return 0;
367}
368
369static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
370			struct pid *pid, struct task_struct *task, int whole)
371{
372	unsigned long vsize, eip, esp, wchan = ~0UL;
373	int priority, nice;
374	int tty_pgrp = -1, tty_nr = 0;
375	sigset_t sigign, sigcatch;
376	char state;
377	pid_t ppid = 0, pgid = -1, sid = -1;
378	int num_threads = 0;
379	int permitted;
380	struct mm_struct *mm;
381	unsigned long long start_time;
382	unsigned long cmin_flt = 0, cmaj_flt = 0;
383	unsigned long  min_flt = 0,  maj_flt = 0;
384	cputime_t cutime, cstime, utime, stime;
385	cputime_t cgtime, gtime;
386	unsigned long rsslim = 0;
387	char tcomm[sizeof(task->comm)];
388	unsigned long flags;
389
390	state = *get_task_state(task);
391	vsize = eip = esp = 0;
392	permitted = ptrace_may_access(task, PTRACE_MODE_READ | PTRACE_MODE_NOAUDIT);
393	mm = get_task_mm(task);
394	if (mm) {
395		vsize = task_vsize(mm);
396		if (permitted) {
397			eip = KSTK_EIP(task);
398			esp = KSTK_ESP(task);
399		}
400	}
401
402	get_task_comm(tcomm, task);
403
404	sigemptyset(&sigign);
405	sigemptyset(&sigcatch);
406	cutime = cstime = utime = stime = 0;
407	cgtime = gtime = 0;
408
409	if (lock_task_sighand(task, &flags)) {
410		struct signal_struct *sig = task->signal;
411
412		if (sig->tty) {
413			struct pid *pgrp = tty_get_pgrp(sig->tty);
414			tty_pgrp = pid_nr_ns(pgrp, ns);
415			put_pid(pgrp);
416			tty_nr = new_encode_dev(tty_devnum(sig->tty));
417		}
418
419		num_threads = get_nr_threads(task);
420		collect_sigign_sigcatch(task, &sigign, &sigcatch);
421
422		cmin_flt = sig->cmin_flt;
423		cmaj_flt = sig->cmaj_flt;
424		cutime = sig->cutime;
425		cstime = sig->cstime;
426		cgtime = sig->cgtime;
427		rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
428
429		/* add up live thread stats at the group level */
430		if (whole) {
431			struct task_struct *t = task;
432			do {
433				min_flt += t->min_flt;
434				maj_flt += t->maj_flt;
435				gtime += t->gtime;
436				t = next_thread(t);
437			} while (t != task);
438
439			min_flt += sig->min_flt;
440			maj_flt += sig->maj_flt;
441			thread_group_times(task, &utime, &stime);
442			gtime += sig->gtime;
443		}
444
445		sid = task_session_nr_ns(task, ns);
446		ppid = task_tgid_nr_ns(task->real_parent, ns);
447		pgid = task_pgrp_nr_ns(task, ns);
448
449		unlock_task_sighand(task, &flags);
450	}
451
452	if (permitted && (!whole || num_threads < 2))
453		wchan = get_wchan(task);
454	if (!whole) {
455		min_flt = task->min_flt;
456		maj_flt = task->maj_flt;
457		task_times(task, &utime, &stime);
458		gtime = task->gtime;
459	}
460
461	/* scale priority and nice values from timeslices to -20..20 */
462	/* to make it look like a "normal" Unix priority/nice value  */
463	priority = task_prio(task);
464	nice = task_nice(task);
465
466	/* Temporary variable needed for gcc-2.96 */
467	/* convert timespec -> nsec*/
468	start_time =
469		(unsigned long long)task->real_start_time.tv_sec * NSEC_PER_SEC
470				+ task->real_start_time.tv_nsec;
471	/* convert nsec -> ticks */
472	start_time = nsec_to_clock_t(start_time);
473
474	seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
475	seq_put_decimal_ll(m, ' ', ppid);
476	seq_put_decimal_ll(m, ' ', pgid);
477	seq_put_decimal_ll(m, ' ', sid);
478	seq_put_decimal_ll(m, ' ', tty_nr);
479	seq_put_decimal_ll(m, ' ', tty_pgrp);
480	seq_put_decimal_ull(m, ' ', task->flags);
481	seq_put_decimal_ull(m, ' ', min_flt);
482	seq_put_decimal_ull(m, ' ', cmin_flt);
483	seq_put_decimal_ull(m, ' ', maj_flt);
484	seq_put_decimal_ull(m, ' ', cmaj_flt);
485	seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime));
486	seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime));
487	seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime));
488	seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime));
489	seq_put_decimal_ll(m, ' ', priority);
490	seq_put_decimal_ll(m, ' ', nice);
491	seq_put_decimal_ll(m, ' ', num_threads);
492	seq_put_decimal_ull(m, ' ', 0);
493	seq_put_decimal_ull(m, ' ', start_time);
494	seq_put_decimal_ull(m, ' ', vsize);
495	seq_put_decimal_ull(m, ' ', mm ? get_mm_rss(mm) : 0);
496	seq_put_decimal_ull(m, ' ', rsslim);
497	seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->start_code : 1) : 0);
498	seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->end_code : 1) : 0);
499	seq_put_decimal_ull(m, ' ', (permitted && mm) ? mm->start_stack : 0);
500	seq_put_decimal_ull(m, ' ', esp);
501	seq_put_decimal_ull(m, ' ', eip);
502	/* The signal information here is obsolete.
503	 * It must be decimal for Linux 2.0 compatibility.
504	 * Use /proc/#/status for real-time signals.
505	 */
506	seq_put_decimal_ull(m, ' ', task->pending.signal.sig[0] & 0x7fffffffUL);
507	seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL);
508	seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL);
509	seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL);
510	seq_put_decimal_ull(m, ' ', wchan);
511	seq_put_decimal_ull(m, ' ', 0);
512	seq_put_decimal_ull(m, ' ', 0);
513	seq_put_decimal_ll(m, ' ', task->exit_signal);
514	seq_put_decimal_ll(m, ' ', task_cpu(task));
515	seq_put_decimal_ull(m, ' ', task->rt_priority);
516	seq_put_decimal_ull(m, ' ', task->policy);
517	seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task));
518	seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime));
519	seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime));
520
521	if (mm && permitted) {
522		seq_put_decimal_ull(m, ' ', mm->start_data);
523		seq_put_decimal_ull(m, ' ', mm->end_data);
524		seq_put_decimal_ull(m, ' ', mm->start_brk);
525		seq_put_decimal_ull(m, ' ', mm->arg_start);
526		seq_put_decimal_ull(m, ' ', mm->arg_end);
527		seq_put_decimal_ull(m, ' ', mm->env_start);
528		seq_put_decimal_ull(m, ' ', mm->env_end);
529	} else
530		seq_printf(m, " 0 0 0 0 0 0 0");
531
532	if (permitted)
533		seq_put_decimal_ll(m, ' ', task->exit_code);
534	else
535		seq_put_decimal_ll(m, ' ', 0);
536
537	seq_putc(m, '\n');
538	if (mm)
539		mmput(mm);
540	return 0;
541}
542
543int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
544			struct pid *pid, struct task_struct *task)
545{
546	return do_task_stat(m, ns, pid, task, 0);
547}
548
549int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
550			struct pid *pid, struct task_struct *task)
551{
552	return do_task_stat(m, ns, pid, task, 1);
553}
554
555int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
556			struct pid *pid, struct task_struct *task)
557{
558	unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0;
559	struct mm_struct *mm = get_task_mm(task);
560
561	if (mm) {
562		size = task_statm(mm, &shared, &text, &data, &resident);
563		mmput(mm);
564	}
565	/*
566	 * For quick read, open code by putting numbers directly
567	 * expected format is
568	 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
569	 *               size, resident, shared, text, data);
570	 */
571	seq_put_decimal_ull(m, 0, size);
572	seq_put_decimal_ull(m, ' ', resident);
573	seq_put_decimal_ull(m, ' ', shared);
574	seq_put_decimal_ull(m, ' ', text);
575	seq_put_decimal_ull(m, ' ', 0);
576	seq_put_decimal_ull(m, ' ', data);
577	seq_put_decimal_ull(m, ' ', 0);
578	seq_putc(m, '\n');
579
580	return 0;
581}
582
583#ifdef CONFIG_CHECKPOINT_RESTORE
584static struct pid *
585get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
586{
587	struct task_struct *start, *task;
588	struct pid *pid = NULL;
589
590	read_lock(&tasklist_lock);
591
592	start = pid_task(proc_pid(inode), PIDTYPE_PID);
593	if (!start)
594		goto out;
595
596	/*
597	 * Lets try to continue searching first, this gives
598	 * us significant speedup on children-rich processes.
599	 */
600	if (pid_prev) {
601		task = pid_task(pid_prev, PIDTYPE_PID);
602		if (task && task->real_parent == start &&
603		    !(list_empty(&task->sibling))) {
604			if (list_is_last(&task->sibling, &start->children))
605				goto out;
606			task = list_first_entry(&task->sibling,
607						struct task_struct, sibling);
608			pid = get_pid(task_pid(task));
609			goto out;
610		}
611	}
612
613	/*
614	 * Slow search case.
615	 *
616	 * We might miss some children here if children
617	 * are exited while we were not holding the lock,
618	 * but it was never promised to be accurate that
619	 * much.
620	 *
621	 * "Just suppose that the parent sleeps, but N children
622	 *  exit after we printed their tids. Now the slow paths
623	 *  skips N extra children, we miss N tasks." (c)
624	 *
625	 * So one need to stop or freeze the leader and all
626	 * its children to get a precise result.
627	 */
628	list_for_each_entry(task, &start->children, sibling) {
629		if (pos-- == 0) {
630			pid = get_pid(task_pid(task));
631			break;
632		}
633	}
634
635out:
636	read_unlock(&tasklist_lock);
637	return pid;
638}
639
640static int children_seq_show(struct seq_file *seq, void *v)
641{
642	struct inode *inode = seq->private;
643	pid_t pid;
644
645	pid = pid_nr_ns(v, inode->i_sb->s_fs_info);
646	return seq_printf(seq, "%d ", pid);
647}
648
649static void *children_seq_start(struct seq_file *seq, loff_t *pos)
650{
651	return get_children_pid(seq->private, NULL, *pos);
652}
653
654static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
655{
656	struct pid *pid;
657
658	pid = get_children_pid(seq->private, v, *pos + 1);
659	put_pid(v);
660
661	++*pos;
662	return pid;
663}
664
665static void children_seq_stop(struct seq_file *seq, void *v)
666{
667	put_pid(v);
668}
669
670static const struct seq_operations children_seq_ops = {
671	.start	= children_seq_start,
672	.next	= children_seq_next,
673	.stop	= children_seq_stop,
674	.show	= children_seq_show,
675};
676
677static int children_seq_open(struct inode *inode, struct file *file)
678{
679	struct seq_file *m;
680	int ret;
681
682	ret = seq_open(file, &children_seq_ops);
683	if (ret)
684		return ret;
685
686	m = file->private_data;
687	m->private = inode;
688
689	return ret;
690}
691
692int children_seq_release(struct inode *inode, struct file *file)
693{
694	seq_release(inode, file);
695	return 0;
696}
697
698const struct file_operations proc_tid_children_operations = {
699	.open    = children_seq_open,
700	.read    = seq_read,
701	.llseek  = seq_lseek,
702	.release = children_seq_release,
703};
704#endif /* CONFIG_CHECKPOINT_RESTORE */