xref: /openbmc/linux/fs/proc/array.c (revision b285d2ae)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/proc/array.c
4  *
5  *  Copyright (C) 1992  by Linus Torvalds
6  *  based on ideas by Darren Senn
7  *
8  * Fixes:
9  * Michael. K. Johnson: stat,statm extensions.
10  *                      <johnsonm@stolaf.edu>
11  *
12  * Pauline Middelink :  Made cmdline,envline only break at '\0's, to
13  *                      make sure SET_PROCTITLE works. Also removed
14  *                      bad '!' which forced address recalculation for
15  *                      EVERY character on the current page.
16  *                      <middelin@polyware.iaf.nl>
17  *
18  * Danny ter Haar    :	added cpuinfo
19  *			<dth@cistron.nl>
20  *
21  * Alessandro Rubini :  profile extension.
22  *                      <rubini@ipvvis.unipv.it>
23  *
24  * Jeff Tranter      :  added BogoMips field to cpuinfo
25  *                      <Jeff_Tranter@Mitel.COM>
26  *
27  * Bruno Haible      :  remove 4K limit for the maps file
28  *			<haible@ma2s2.mathematik.uni-karlsruhe.de>
29  *
30  * Yves Arrouye      :  remove removal of trailing spaces in get_array.
31  *			<Yves.Arrouye@marin.fdn.fr>
32  *
33  * Jerome Forissier  :  added per-CPU time information to /proc/stat
34  *                      and /proc/<pid>/cpu extension
35  *                      <forissier@isia.cma.fr>
36  *			- Incorporation and non-SMP safe operation
37  *			of forissier patch in 2.1.78 by
38  *			Hans Marcus <crowbar@concepts.nl>
39  *
40  * aeb@cwi.nl        :  /proc/partitions
41  *
42  *
43  * Alan Cox	     :  security fixes.
44  *			<alan@lxorguk.ukuu.org.uk>
45  *
46  * Al Viro           :  safe handling of mm_struct
47  *
48  * Gerhard Wichert   :  added BIGMEM support
49  * Siemens AG           <Gerhard.Wichert@pdb.siemens.de>
50  *
51  * Al Viro & Jeff Garzik :  moved most of the thing into base.c and
52  *			 :  proc_misc.c. The rest may eventually go into
53  *			 :  base.c too.
54  */
55 
56 #include <linux/types.h>
57 #include <linux/errno.h>
58 #include <linux/time.h>
59 #include <linux/kernel.h>
60 #include <linux/kernel_stat.h>
61 #include <linux/tty.h>
62 #include <linux/string.h>
63 #include <linux/mman.h>
64 #include <linux/sched/mm.h>
65 #include <linux/sched/numa_balancing.h>
66 #include <linux/sched/task_stack.h>
67 #include <linux/sched/task.h>
68 #include <linux/sched/cputime.h>
69 #include <linux/proc_fs.h>
70 #include <linux/ioport.h>
71 #include <linux/uaccess.h>
72 #include <linux/io.h>
73 #include <linux/mm.h>
74 #include <linux/hugetlb.h>
75 #include <linux/pagemap.h>
76 #include <linux/swap.h>
77 #include <linux/smp.h>
78 #include <linux/signal.h>
79 #include <linux/highmem.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/times.h>
83 #include <linux/cpuset.h>
84 #include <linux/rcupdate.h>
85 #include <linux/delayacct.h>
86 #include <linux/seq_file.h>
87 #include <linux/pid_namespace.h>
88 #include <linux/prctl.h>
89 #include <linux/ptrace.h>
90 #include <linux/tracehook.h>
91 #include <linux/string_helpers.h>
92 #include <linux/user_namespace.h>
93 #include <linux/fs_struct.h>
94 
95 #include <asm/processor.h>
96 #include "internal.h"
97 
98 void proc_task_name(struct seq_file *m, struct task_struct *p, bool escape)
99 {
100 	char *buf;
101 	size_t size;
102 	char tcomm[64];
103 	int ret;
104 
105 	if (p->flags & PF_WQ_WORKER)
106 		wq_worker_comm(tcomm, sizeof(tcomm), p);
107 	else
108 		__get_task_comm(tcomm, sizeof(tcomm), p);
109 
110 	size = seq_get_buf(m, &buf);
111 	if (escape) {
112 		ret = string_escape_str(tcomm, buf, size,
113 					ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
114 		if (ret >= size)
115 			ret = -1;
116 	} else {
117 		ret = strscpy(buf, tcomm, size);
118 	}
119 
120 	seq_commit(m, ret);
121 }
122 
123 /*
124  * The task state array is a strange "bitmap" of
125  * reasons to sleep. Thus "running" is zero, and
126  * you can test for combinations of others with
127  * simple bit tests.
128  */
129 static const char * const task_state_array[] = {
130 
131 	/* states in TASK_REPORT: */
132 	"R (running)",		/* 0x00 */
133 	"S (sleeping)",		/* 0x01 */
134 	"D (disk sleep)",	/* 0x02 */
135 	"T (stopped)",		/* 0x04 */
136 	"t (tracing stop)",	/* 0x08 */
137 	"X (dead)",		/* 0x10 */
138 	"Z (zombie)",		/* 0x20 */
139 	"P (parked)",		/* 0x40 */
140 
141 	/* states beyond TASK_REPORT: */
142 	"I (idle)",		/* 0x80 */
143 };
144 
145 static inline const char *get_task_state(struct task_struct *tsk)
146 {
147 	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != ARRAY_SIZE(task_state_array));
148 	return task_state_array[task_state_index(tsk)];
149 }
150 
151 static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
152 				struct pid *pid, struct task_struct *p)
153 {
154 	struct user_namespace *user_ns = seq_user_ns(m);
155 	struct group_info *group_info;
156 	int g, umask = -1;
157 	struct task_struct *tracer;
158 	const struct cred *cred;
159 	pid_t ppid, tpid = 0, tgid, ngid;
160 	unsigned int max_fds = 0;
161 
162 	rcu_read_lock();
163 	ppid = pid_alive(p) ?
164 		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
165 
166 	tracer = ptrace_parent(p);
167 	if (tracer)
168 		tpid = task_pid_nr_ns(tracer, ns);
169 
170 	tgid = task_tgid_nr_ns(p, ns);
171 	ngid = task_numa_group_id(p);
172 	cred = get_task_cred(p);
173 
174 	task_lock(p);
175 	if (p->fs)
176 		umask = p->fs->umask;
177 	if (p->files)
178 		max_fds = files_fdtable(p->files)->max_fds;
179 	task_unlock(p);
180 	rcu_read_unlock();
181 
182 	if (umask >= 0)
183 		seq_printf(m, "Umask:\t%#04o\n", umask);
184 	seq_puts(m, "State:\t");
185 	seq_puts(m, get_task_state(p));
186 
187 	seq_put_decimal_ull(m, "\nTgid:\t", tgid);
188 	seq_put_decimal_ull(m, "\nNgid:\t", ngid);
189 	seq_put_decimal_ull(m, "\nPid:\t", pid_nr_ns(pid, ns));
190 	seq_put_decimal_ull(m, "\nPPid:\t", ppid);
191 	seq_put_decimal_ull(m, "\nTracerPid:\t", tpid);
192 	seq_put_decimal_ull(m, "\nUid:\t", from_kuid_munged(user_ns, cred->uid));
193 	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->euid));
194 	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->suid));
195 	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->fsuid));
196 	seq_put_decimal_ull(m, "\nGid:\t", from_kgid_munged(user_ns, cred->gid));
197 	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->egid));
198 	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->sgid));
199 	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->fsgid));
200 	seq_put_decimal_ull(m, "\nFDSize:\t", max_fds);
201 
202 	seq_puts(m, "\nGroups:\t");
203 	group_info = cred->group_info;
204 	for (g = 0; g < group_info->ngroups; g++)
205 		seq_put_decimal_ull(m, g ? " " : "",
206 				from_kgid_munged(user_ns, group_info->gid[g]));
207 	put_cred(cred);
208 	/* Trailing space shouldn't have been added in the first place. */
209 	seq_putc(m, ' ');
210 
211 #ifdef CONFIG_PID_NS
212 	seq_puts(m, "\nNStgid:");
213 	for (g = ns->level; g <= pid->level; g++)
214 		seq_put_decimal_ull(m, "\t", task_tgid_nr_ns(p, pid->numbers[g].ns));
215 	seq_puts(m, "\nNSpid:");
216 	for (g = ns->level; g <= pid->level; g++)
217 		seq_put_decimal_ull(m, "\t", task_pid_nr_ns(p, pid->numbers[g].ns));
218 	seq_puts(m, "\nNSpgid:");
219 	for (g = ns->level; g <= pid->level; g++)
220 		seq_put_decimal_ull(m, "\t", task_pgrp_nr_ns(p, pid->numbers[g].ns));
221 	seq_puts(m, "\nNSsid:");
222 	for (g = ns->level; g <= pid->level; g++)
223 		seq_put_decimal_ull(m, "\t", task_session_nr_ns(p, pid->numbers[g].ns));
224 #endif
225 	seq_putc(m, '\n');
226 }
227 
228 void render_sigset_t(struct seq_file *m, const char *header,
229 				sigset_t *set)
230 {
231 	int i;
232 
233 	seq_puts(m, header);
234 
235 	i = _NSIG;
236 	do {
237 		int x = 0;
238 
239 		i -= 4;
240 		if (sigismember(set, i+1)) x |= 1;
241 		if (sigismember(set, i+2)) x |= 2;
242 		if (sigismember(set, i+3)) x |= 4;
243 		if (sigismember(set, i+4)) x |= 8;
244 		seq_putc(m, hex_asc[x]);
245 	} while (i >= 4);
246 
247 	seq_putc(m, '\n');
248 }
249 
250 static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *sigign,
251 				    sigset_t *sigcatch)
252 {
253 	struct k_sigaction *k;
254 	int i;
255 
256 	k = p->sighand->action;
257 	for (i = 1; i <= _NSIG; ++i, ++k) {
258 		if (k->sa.sa_handler == SIG_IGN)
259 			sigaddset(sigign, i);
260 		else if (k->sa.sa_handler != SIG_DFL)
261 			sigaddset(sigcatch, i);
262 	}
263 }
264 
265 static inline void task_sig(struct seq_file *m, struct task_struct *p)
266 {
267 	unsigned long flags;
268 	sigset_t pending, shpending, blocked, ignored, caught;
269 	int num_threads = 0;
270 	unsigned int qsize = 0;
271 	unsigned long qlim = 0;
272 
273 	sigemptyset(&pending);
274 	sigemptyset(&shpending);
275 	sigemptyset(&blocked);
276 	sigemptyset(&ignored);
277 	sigemptyset(&caught);
278 
279 	if (lock_task_sighand(p, &flags)) {
280 		pending = p->pending.signal;
281 		shpending = p->signal->shared_pending.signal;
282 		blocked = p->blocked;
283 		collect_sigign_sigcatch(p, &ignored, &caught);
284 		num_threads = get_nr_threads(p);
285 		rcu_read_lock();  /* FIXME: is this correct? */
286 		qsize = atomic_read(&__task_cred(p)->user->sigpending);
287 		rcu_read_unlock();
288 		qlim = task_rlimit(p, RLIMIT_SIGPENDING);
289 		unlock_task_sighand(p, &flags);
290 	}
291 
292 	seq_put_decimal_ull(m, "Threads:\t", num_threads);
293 	seq_put_decimal_ull(m, "\nSigQ:\t", qsize);
294 	seq_put_decimal_ull(m, "/", qlim);
295 
296 	/* render them all */
297 	render_sigset_t(m, "\nSigPnd:\t", &pending);
298 	render_sigset_t(m, "ShdPnd:\t", &shpending);
299 	render_sigset_t(m, "SigBlk:\t", &blocked);
300 	render_sigset_t(m, "SigIgn:\t", &ignored);
301 	render_sigset_t(m, "SigCgt:\t", &caught);
302 }
303 
304 static void render_cap_t(struct seq_file *m, const char *header,
305 			kernel_cap_t *a)
306 {
307 	unsigned __capi;
308 
309 	seq_puts(m, header);
310 	CAP_FOR_EACH_U32(__capi) {
311 		seq_put_hex_ll(m, NULL,
312 			   a->cap[CAP_LAST_U32 - __capi], 8);
313 	}
314 	seq_putc(m, '\n');
315 }
316 
317 static inline void task_cap(struct seq_file *m, struct task_struct *p)
318 {
319 	const struct cred *cred;
320 	kernel_cap_t cap_inheritable, cap_permitted, cap_effective,
321 			cap_bset, cap_ambient;
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 	cap_ambient	= cred->cap_ambient;
330 	rcu_read_unlock();
331 
332 	render_cap_t(m, "CapInh:\t", &cap_inheritable);
333 	render_cap_t(m, "CapPrm:\t", &cap_permitted);
334 	render_cap_t(m, "CapEff:\t", &cap_effective);
335 	render_cap_t(m, "CapBnd:\t", &cap_bset);
336 	render_cap_t(m, "CapAmb:\t", &cap_ambient);
337 }
338 
339 static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
340 {
341 	seq_put_decimal_ull(m, "NoNewPrivs:\t", task_no_new_privs(p));
342 #ifdef CONFIG_SECCOMP
343 	seq_put_decimal_ull(m, "\nSeccomp:\t", p->seccomp.mode);
344 	seq_put_decimal_ull(m, "\nSeccomp_filters:\t",
345 			    atomic_read(&p->seccomp.filter_count));
346 #endif
347 	seq_puts(m, "\nSpeculation_Store_Bypass:\t");
348 	switch (arch_prctl_spec_ctrl_get(p, PR_SPEC_STORE_BYPASS)) {
349 	case -EINVAL:
350 		seq_puts(m, "unknown");
351 		break;
352 	case PR_SPEC_NOT_AFFECTED:
353 		seq_puts(m, "not vulnerable");
354 		break;
355 	case PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE:
356 		seq_puts(m, "thread force mitigated");
357 		break;
358 	case PR_SPEC_PRCTL | PR_SPEC_DISABLE:
359 		seq_puts(m, "thread mitigated");
360 		break;
361 	case PR_SPEC_PRCTL | PR_SPEC_ENABLE:
362 		seq_puts(m, "thread vulnerable");
363 		break;
364 	case PR_SPEC_DISABLE:
365 		seq_puts(m, "globally mitigated");
366 		break;
367 	default:
368 		seq_puts(m, "vulnerable");
369 		break;
370 	}
371 	seq_putc(m, '\n');
372 }
373 
374 static inline void task_context_switch_counts(struct seq_file *m,
375 						struct task_struct *p)
376 {
377 	seq_put_decimal_ull(m, "voluntary_ctxt_switches:\t", p->nvcsw);
378 	seq_put_decimal_ull(m, "\nnonvoluntary_ctxt_switches:\t", p->nivcsw);
379 	seq_putc(m, '\n');
380 }
381 
382 static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
383 {
384 	seq_printf(m, "Cpus_allowed:\t%*pb\n",
385 		   cpumask_pr_args(task->cpus_ptr));
386 	seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
387 		   cpumask_pr_args(task->cpus_ptr));
388 }
389 
390 static inline void task_core_dumping(struct seq_file *m, struct mm_struct *mm)
391 {
392 	seq_put_decimal_ull(m, "CoreDumping:\t", !!mm->core_state);
393 	seq_putc(m, '\n');
394 }
395 
396 static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm)
397 {
398 	bool thp_enabled = IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE);
399 
400 	if (thp_enabled)
401 		thp_enabled = !test_bit(MMF_DISABLE_THP, &mm->flags);
402 	seq_printf(m, "THP_enabled:\t%d\n", thp_enabled);
403 }
404 
405 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
406 			struct pid *pid, struct task_struct *task)
407 {
408 	struct mm_struct *mm = get_task_mm(task);
409 
410 	seq_puts(m, "Name:\t");
411 	proc_task_name(m, task, true);
412 	seq_putc(m, '\n');
413 
414 	task_state(m, ns, pid, task);
415 
416 	if (mm) {
417 		task_mem(m, mm);
418 		task_core_dumping(m, mm);
419 		task_thp_status(m, mm);
420 		mmput(mm);
421 	}
422 	task_sig(m, task);
423 	task_cap(m, task);
424 	task_seccomp(m, task);
425 	task_cpus_allowed(m, task);
426 	cpuset_task_status_allowed(m, task);
427 	task_context_switch_counts(m, task);
428 	return 0;
429 }
430 
431 static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
432 			struct pid *pid, struct task_struct *task, int whole)
433 {
434 	unsigned long vsize, eip, esp, wchan = 0;
435 	int priority, nice;
436 	int tty_pgrp = -1, tty_nr = 0;
437 	sigset_t sigign, sigcatch;
438 	char state;
439 	pid_t ppid = 0, pgid = -1, sid = -1;
440 	int num_threads = 0;
441 	int permitted;
442 	struct mm_struct *mm;
443 	unsigned long long start_time;
444 	unsigned long cmin_flt = 0, cmaj_flt = 0;
445 	unsigned long  min_flt = 0,  maj_flt = 0;
446 	u64 cutime, cstime, utime, stime;
447 	u64 cgtime, gtime;
448 	unsigned long rsslim = 0;
449 	unsigned long flags;
450 
451 	state = *get_task_state(task);
452 	vsize = eip = esp = 0;
453 	permitted = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS | PTRACE_MODE_NOAUDIT);
454 	mm = get_task_mm(task);
455 	if (mm) {
456 		vsize = task_vsize(mm);
457 		/*
458 		 * esp and eip are intentionally zeroed out.  There is no
459 		 * non-racy way to read them without freezing the task.
460 		 * Programs that need reliable values can use ptrace(2).
461 		 *
462 		 * The only exception is if the task is core dumping because
463 		 * a program is not able to use ptrace(2) in that case. It is
464 		 * safe because the task has stopped executing permanently.
465 		 */
466 		if (permitted && (task->flags & (PF_EXITING|PF_DUMPCORE))) {
467 			if (try_get_task_stack(task)) {
468 				eip = KSTK_EIP(task);
469 				esp = KSTK_ESP(task);
470 				put_task_stack(task);
471 			}
472 		}
473 	}
474 
475 	sigemptyset(&sigign);
476 	sigemptyset(&sigcatch);
477 	cutime = cstime = utime = stime = 0;
478 	cgtime = gtime = 0;
479 
480 	if (lock_task_sighand(task, &flags)) {
481 		struct signal_struct *sig = task->signal;
482 
483 		if (sig->tty) {
484 			struct pid *pgrp = tty_get_pgrp(sig->tty);
485 			tty_pgrp = pid_nr_ns(pgrp, ns);
486 			put_pid(pgrp);
487 			tty_nr = new_encode_dev(tty_devnum(sig->tty));
488 		}
489 
490 		num_threads = get_nr_threads(task);
491 		collect_sigign_sigcatch(task, &sigign, &sigcatch);
492 
493 		cmin_flt = sig->cmin_flt;
494 		cmaj_flt = sig->cmaj_flt;
495 		cutime = sig->cutime;
496 		cstime = sig->cstime;
497 		cgtime = sig->cgtime;
498 		rsslim = READ_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
499 
500 		/* add up live thread stats at the group level */
501 		if (whole) {
502 			struct task_struct *t = task;
503 			do {
504 				min_flt += t->min_flt;
505 				maj_flt += t->maj_flt;
506 				gtime += task_gtime(t);
507 			} while_each_thread(task, t);
508 
509 			min_flt += sig->min_flt;
510 			maj_flt += sig->maj_flt;
511 			thread_group_cputime_adjusted(task, &utime, &stime);
512 			gtime += sig->gtime;
513 		}
514 
515 		sid = task_session_nr_ns(task, ns);
516 		ppid = task_tgid_nr_ns(task->real_parent, ns);
517 		pgid = task_pgrp_nr_ns(task, ns);
518 
519 		unlock_task_sighand(task, &flags);
520 	}
521 
522 	if (permitted && (!whole || num_threads < 2))
523 		wchan = get_wchan(task);
524 	if (!whole) {
525 		min_flt = task->min_flt;
526 		maj_flt = task->maj_flt;
527 		task_cputime_adjusted(task, &utime, &stime);
528 		gtime = task_gtime(task);
529 	}
530 
531 	/* scale priority and nice values from timeslices to -20..20 */
532 	/* to make it look like a "normal" Unix priority/nice value  */
533 	priority = task_prio(task);
534 	nice = task_nice(task);
535 
536 	/* convert nsec -> ticks */
537 	start_time = nsec_to_clock_t(task->start_boottime);
538 
539 	seq_put_decimal_ull(m, "", pid_nr_ns(pid, ns));
540 	seq_puts(m, " (");
541 	proc_task_name(m, task, false);
542 	seq_puts(m, ") ");
543 	seq_putc(m, state);
544 	seq_put_decimal_ll(m, " ", ppid);
545 	seq_put_decimal_ll(m, " ", pgid);
546 	seq_put_decimal_ll(m, " ", sid);
547 	seq_put_decimal_ll(m, " ", tty_nr);
548 	seq_put_decimal_ll(m, " ", tty_pgrp);
549 	seq_put_decimal_ull(m, " ", task->flags);
550 	seq_put_decimal_ull(m, " ", min_flt);
551 	seq_put_decimal_ull(m, " ", cmin_flt);
552 	seq_put_decimal_ull(m, " ", maj_flt);
553 	seq_put_decimal_ull(m, " ", cmaj_flt);
554 	seq_put_decimal_ull(m, " ", nsec_to_clock_t(utime));
555 	seq_put_decimal_ull(m, " ", nsec_to_clock_t(stime));
556 	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cutime));
557 	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cstime));
558 	seq_put_decimal_ll(m, " ", priority);
559 	seq_put_decimal_ll(m, " ", nice);
560 	seq_put_decimal_ll(m, " ", num_threads);
561 	seq_put_decimal_ull(m, " ", 0);
562 	seq_put_decimal_ull(m, " ", start_time);
563 	seq_put_decimal_ull(m, " ", vsize);
564 	seq_put_decimal_ull(m, " ", mm ? get_mm_rss(mm) : 0);
565 	seq_put_decimal_ull(m, " ", rsslim);
566 	seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->start_code : 1) : 0);
567 	seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->end_code : 1) : 0);
568 	seq_put_decimal_ull(m, " ", (permitted && mm) ? mm->start_stack : 0);
569 	seq_put_decimal_ull(m, " ", esp);
570 	seq_put_decimal_ull(m, " ", eip);
571 	/* The signal information here is obsolete.
572 	 * It must be decimal for Linux 2.0 compatibility.
573 	 * Use /proc/#/status for real-time signals.
574 	 */
575 	seq_put_decimal_ull(m, " ", task->pending.signal.sig[0] & 0x7fffffffUL);
576 	seq_put_decimal_ull(m, " ", task->blocked.sig[0] & 0x7fffffffUL);
577 	seq_put_decimal_ull(m, " ", sigign.sig[0] & 0x7fffffffUL);
578 	seq_put_decimal_ull(m, " ", sigcatch.sig[0] & 0x7fffffffUL);
579 
580 	/*
581 	 * We used to output the absolute kernel address, but that's an
582 	 * information leak - so instead we show a 0/1 flag here, to signal
583 	 * to user-space whether there's a wchan field in /proc/PID/wchan.
584 	 *
585 	 * This works with older implementations of procps as well.
586 	 */
587 	if (wchan)
588 		seq_puts(m, " 1");
589 	else
590 		seq_puts(m, " 0");
591 
592 	seq_put_decimal_ull(m, " ", 0);
593 	seq_put_decimal_ull(m, " ", 0);
594 	seq_put_decimal_ll(m, " ", task->exit_signal);
595 	seq_put_decimal_ll(m, " ", task_cpu(task));
596 	seq_put_decimal_ull(m, " ", task->rt_priority);
597 	seq_put_decimal_ull(m, " ", task->policy);
598 	seq_put_decimal_ull(m, " ", delayacct_blkio_ticks(task));
599 	seq_put_decimal_ull(m, " ", nsec_to_clock_t(gtime));
600 	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cgtime));
601 
602 	if (mm && permitted) {
603 		seq_put_decimal_ull(m, " ", mm->start_data);
604 		seq_put_decimal_ull(m, " ", mm->end_data);
605 		seq_put_decimal_ull(m, " ", mm->start_brk);
606 		seq_put_decimal_ull(m, " ", mm->arg_start);
607 		seq_put_decimal_ull(m, " ", mm->arg_end);
608 		seq_put_decimal_ull(m, " ", mm->env_start);
609 		seq_put_decimal_ull(m, " ", mm->env_end);
610 	} else
611 		seq_puts(m, " 0 0 0 0 0 0 0");
612 
613 	if (permitted)
614 		seq_put_decimal_ll(m, " ", task->exit_code);
615 	else
616 		seq_puts(m, " 0");
617 
618 	seq_putc(m, '\n');
619 	if (mm)
620 		mmput(mm);
621 	return 0;
622 }
623 
624 int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
625 			struct pid *pid, struct task_struct *task)
626 {
627 	return do_task_stat(m, ns, pid, task, 0);
628 }
629 
630 int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
631 			struct pid *pid, struct task_struct *task)
632 {
633 	return do_task_stat(m, ns, pid, task, 1);
634 }
635 
636 int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
637 			struct pid *pid, struct task_struct *task)
638 {
639 	struct mm_struct *mm = get_task_mm(task);
640 
641 	if (mm) {
642 		unsigned long size;
643 		unsigned long resident = 0;
644 		unsigned long shared = 0;
645 		unsigned long text = 0;
646 		unsigned long data = 0;
647 
648 		size = task_statm(mm, &shared, &text, &data, &resident);
649 		mmput(mm);
650 
651 		/*
652 		 * For quick read, open code by putting numbers directly
653 		 * expected format is
654 		 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
655 		 *               size, resident, shared, text, data);
656 		 */
657 		seq_put_decimal_ull(m, "", size);
658 		seq_put_decimal_ull(m, " ", resident);
659 		seq_put_decimal_ull(m, " ", shared);
660 		seq_put_decimal_ull(m, " ", text);
661 		seq_put_decimal_ull(m, " ", 0);
662 		seq_put_decimal_ull(m, " ", data);
663 		seq_put_decimal_ull(m, " ", 0);
664 		seq_putc(m, '\n');
665 	} else {
666 		seq_write(m, "0 0 0 0 0 0 0\n", 14);
667 	}
668 	return 0;
669 }
670 
671 #ifdef CONFIG_PROC_CHILDREN
672 static struct pid *
673 get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
674 {
675 	struct task_struct *start, *task;
676 	struct pid *pid = NULL;
677 
678 	read_lock(&tasklist_lock);
679 
680 	start = pid_task(proc_pid(inode), PIDTYPE_PID);
681 	if (!start)
682 		goto out;
683 
684 	/*
685 	 * Lets try to continue searching first, this gives
686 	 * us significant speedup on children-rich processes.
687 	 */
688 	if (pid_prev) {
689 		task = pid_task(pid_prev, PIDTYPE_PID);
690 		if (task && task->real_parent == start &&
691 		    !(list_empty(&task->sibling))) {
692 			if (list_is_last(&task->sibling, &start->children))
693 				goto out;
694 			task = list_first_entry(&task->sibling,
695 						struct task_struct, sibling);
696 			pid = get_pid(task_pid(task));
697 			goto out;
698 		}
699 	}
700 
701 	/*
702 	 * Slow search case.
703 	 *
704 	 * We might miss some children here if children
705 	 * are exited while we were not holding the lock,
706 	 * but it was never promised to be accurate that
707 	 * much.
708 	 *
709 	 * "Just suppose that the parent sleeps, but N children
710 	 *  exit after we printed their tids. Now the slow paths
711 	 *  skips N extra children, we miss N tasks." (c)
712 	 *
713 	 * So one need to stop or freeze the leader and all
714 	 * its children to get a precise result.
715 	 */
716 	list_for_each_entry(task, &start->children, sibling) {
717 		if (pos-- == 0) {
718 			pid = get_pid(task_pid(task));
719 			break;
720 		}
721 	}
722 
723 out:
724 	read_unlock(&tasklist_lock);
725 	return pid;
726 }
727 
728 static int children_seq_show(struct seq_file *seq, void *v)
729 {
730 	struct inode *inode = file_inode(seq->file);
731 
732 	seq_printf(seq, "%d ", pid_nr_ns(v, proc_pid_ns(inode->i_sb)));
733 	return 0;
734 }
735 
736 static void *children_seq_start(struct seq_file *seq, loff_t *pos)
737 {
738 	return get_children_pid(file_inode(seq->file), NULL, *pos);
739 }
740 
741 static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
742 {
743 	struct pid *pid;
744 
745 	pid = get_children_pid(file_inode(seq->file), v, *pos + 1);
746 	put_pid(v);
747 
748 	++*pos;
749 	return pid;
750 }
751 
752 static void children_seq_stop(struct seq_file *seq, void *v)
753 {
754 	put_pid(v);
755 }
756 
757 static const struct seq_operations children_seq_ops = {
758 	.start	= children_seq_start,
759 	.next	= children_seq_next,
760 	.stop	= children_seq_stop,
761 	.show	= children_seq_show,
762 };
763 
764 static int children_seq_open(struct inode *inode, struct file *file)
765 {
766 	return seq_open(file, &children_seq_ops);
767 }
768 
769 const struct file_operations proc_tid_children_operations = {
770 	.open    = children_seq_open,
771 	.read    = seq_read,
772 	.llseek  = seq_lseek,
773 	.release = seq_release,
774 };
775 #endif /* CONFIG_PROC_CHILDREN */
776