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Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm...
[linux-2.6.git] / fs / proc / array.c
blob1bd2077187fd000a621e2f10453ce0661e908c02
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 */
Linus' kernel tree