xref: /openbmc/linux/fs/proc/base.c (revision 217188d9)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/proc/base.c
4  *
5  *  Copyright (C) 1991, 1992 Linus Torvalds
6  *
7  *  proc base directory handling functions
8  *
9  *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
10  *  Instead of using magical inumbers to determine the kind of object
11  *  we allocate and fill in-core inodes upon lookup. They don't even
12  *  go into icache. We cache the reference to task_struct upon lookup too.
13  *  Eventually it should become a filesystem in its own. We don't use the
14  *  rest of procfs anymore.
15  *
16  *
17  *  Changelog:
18  *  17-Jan-2005
19  *  Allan Bezerra
20  *  Bruna Moreira <bruna.moreira@indt.org.br>
21  *  Edjard Mota <edjard.mota@indt.org.br>
22  *  Ilias Biris <ilias.biris@indt.org.br>
23  *  Mauricio Lin <mauricio.lin@indt.org.br>
24  *
25  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
26  *
27  *  A new process specific entry (smaps) included in /proc. It shows the
28  *  size of rss for each memory area. The maps entry lacks information
29  *  about physical memory size (rss) for each mapped file, i.e.,
30  *  rss information for executables and library files.
31  *  This additional information is useful for any tools that need to know
32  *  about physical memory consumption for a process specific library.
33  *
34  *  Changelog:
35  *  21-Feb-2005
36  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
37  *  Pud inclusion in the page table walking.
38  *
39  *  ChangeLog:
40  *  10-Mar-2005
41  *  10LE Instituto Nokia de Tecnologia - INdT:
42  *  A better way to walks through the page table as suggested by Hugh Dickins.
43  *
44  *  Simo Piiroinen <simo.piiroinen@nokia.com>:
45  *  Smaps information related to shared, private, clean and dirty pages.
46  *
47  *  Paul Mundt <paul.mundt@nokia.com>:
48  *  Overall revision about smaps.
49  */
50 
51 #include <linux/uaccess.h>
52 
53 #include <linux/errno.h>
54 #include <linux/time.h>
55 #include <linux/proc_fs.h>
56 #include <linux/stat.h>
57 #include <linux/task_io_accounting_ops.h>
58 #include <linux/init.h>
59 #include <linux/capability.h>
60 #include <linux/file.h>
61 #include <linux/fdtable.h>
62 #include <linux/string.h>
63 #include <linux/seq_file.h>
64 #include <linux/namei.h>
65 #include <linux/mnt_namespace.h>
66 #include <linux/mm.h>
67 #include <linux/swap.h>
68 #include <linux/rcupdate.h>
69 #include <linux/kallsyms.h>
70 #include <linux/stacktrace.h>
71 #include <linux/resource.h>
72 #include <linux/module.h>
73 #include <linux/mount.h>
74 #include <linux/security.h>
75 #include <linux/ptrace.h>
76 #include <linux/tracehook.h>
77 #include <linux/printk.h>
78 #include <linux/cache.h>
79 #include <linux/cgroup.h>
80 #include <linux/cpuset.h>
81 #include <linux/audit.h>
82 #include <linux/poll.h>
83 #include <linux/nsproxy.h>
84 #include <linux/oom.h>
85 #include <linux/elf.h>
86 #include <linux/pid_namespace.h>
87 #include <linux/user_namespace.h>
88 #include <linux/fs_struct.h>
89 #include <linux/slab.h>
90 #include <linux/sched/autogroup.h>
91 #include <linux/sched/mm.h>
92 #include <linux/sched/coredump.h>
93 #include <linux/sched/debug.h>
94 #include <linux/sched/stat.h>
95 #include <linux/flex_array.h>
96 #include <linux/posix-timers.h>
97 #include <trace/events/oom.h>
98 #include "internal.h"
99 #include "fd.h"
100 
101 #include "../../lib/kstrtox.h"
102 
103 /* NOTE:
104  *	Implementing inode permission operations in /proc is almost
105  *	certainly an error.  Permission checks need to happen during
106  *	each system call not at open time.  The reason is that most of
107  *	what we wish to check for permissions in /proc varies at runtime.
108  *
109  *	The classic example of a problem is opening file descriptors
110  *	in /proc for a task before it execs a suid executable.
111  */
112 
113 static u8 nlink_tid __ro_after_init;
114 static u8 nlink_tgid __ro_after_init;
115 
116 struct pid_entry {
117 	const char *name;
118 	unsigned int len;
119 	umode_t mode;
120 	const struct inode_operations *iop;
121 	const struct file_operations *fop;
122 	union proc_op op;
123 };
124 
125 #define NOD(NAME, MODE, IOP, FOP, OP) {			\
126 	.name = (NAME),					\
127 	.len  = sizeof(NAME) - 1,			\
128 	.mode = MODE,					\
129 	.iop  = IOP,					\
130 	.fop  = FOP,					\
131 	.op   = OP,					\
132 }
133 
134 #define DIR(NAME, MODE, iops, fops)	\
135 	NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
136 #define LNK(NAME, get_link)					\
137 	NOD(NAME, (S_IFLNK|S_IRWXUGO),				\
138 		&proc_pid_link_inode_operations, NULL,		\
139 		{ .proc_get_link = get_link } )
140 #define REG(NAME, MODE, fops)				\
141 	NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
142 #define ONE(NAME, MODE, show)				\
143 	NOD(NAME, (S_IFREG|(MODE)), 			\
144 		NULL, &proc_single_file_operations,	\
145 		{ .proc_show = show } )
146 
147 /*
148  * Count the number of hardlinks for the pid_entry table, excluding the .
149  * and .. links.
150  */
151 static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
152 	unsigned int n)
153 {
154 	unsigned int i;
155 	unsigned int count;
156 
157 	count = 2;
158 	for (i = 0; i < n; ++i) {
159 		if (S_ISDIR(entries[i].mode))
160 			++count;
161 	}
162 
163 	return count;
164 }
165 
166 static int get_task_root(struct task_struct *task, struct path *root)
167 {
168 	int result = -ENOENT;
169 
170 	task_lock(task);
171 	if (task->fs) {
172 		get_fs_root(task->fs, root);
173 		result = 0;
174 	}
175 	task_unlock(task);
176 	return result;
177 }
178 
179 static int proc_cwd_link(struct dentry *dentry, struct path *path)
180 {
181 	struct task_struct *task = get_proc_task(d_inode(dentry));
182 	int result = -ENOENT;
183 
184 	if (task) {
185 		task_lock(task);
186 		if (task->fs) {
187 			get_fs_pwd(task->fs, path);
188 			result = 0;
189 		}
190 		task_unlock(task);
191 		put_task_struct(task);
192 	}
193 	return result;
194 }
195 
196 static int proc_root_link(struct dentry *dentry, struct path *path)
197 {
198 	struct task_struct *task = get_proc_task(d_inode(dentry));
199 	int result = -ENOENT;
200 
201 	if (task) {
202 		result = get_task_root(task, path);
203 		put_task_struct(task);
204 	}
205 	return result;
206 }
207 
208 static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
209 			      size_t count, loff_t *ppos)
210 {
211 	unsigned long arg_start, arg_end, env_start, env_end;
212 	unsigned long pos, len;
213 	char *page;
214 
215 	/* Check if process spawned far enough to have cmdline. */
216 	if (!mm->env_end)
217 		return 0;
218 
219 	spin_lock(&mm->arg_lock);
220 	arg_start = mm->arg_start;
221 	arg_end = mm->arg_end;
222 	env_start = mm->env_start;
223 	env_end = mm->env_end;
224 	spin_unlock(&mm->arg_lock);
225 
226 	if (arg_start >= arg_end)
227 		return 0;
228 
229 	/*
230 	 * We have traditionally allowed the user to re-write
231 	 * the argument strings and overflow the end result
232 	 * into the environment section. But only do that if
233 	 * the environment area is contiguous to the arguments.
234 	 */
235 	if (env_start != arg_end || env_start >= env_end)
236 		env_start = env_end = arg_end;
237 
238 	/* .. and limit it to a maximum of one page of slop */
239 	if (env_end >= arg_end + PAGE_SIZE)
240 		env_end = arg_end + PAGE_SIZE - 1;
241 
242 	/* We're not going to care if "*ppos" has high bits set */
243 	pos = arg_start + *ppos;
244 
245 	/* .. but we do check the result is in the proper range */
246 	if (pos < arg_start || pos >= env_end)
247 		return 0;
248 
249 	/* .. and we never go past env_end */
250 	if (env_end - pos < count)
251 		count = env_end - pos;
252 
253 	page = (char *)__get_free_page(GFP_KERNEL);
254 	if (!page)
255 		return -ENOMEM;
256 
257 	len = 0;
258 	while (count) {
259 		int got;
260 		size_t size = min_t(size_t, PAGE_SIZE, count);
261 		long offset;
262 
263 		/*
264 		 * Are we already starting past the official end?
265 		 * We always include the last byte that is *supposed*
266 		 * to be NUL
267 		 */
268 		offset = (pos >= arg_end) ? pos - arg_end + 1 : 0;
269 
270 		got = access_remote_vm(mm, pos - offset, page, size + offset, FOLL_ANON);
271 		if (got <= offset)
272 			break;
273 		got -= offset;
274 
275 		/* Don't walk past a NUL character once you hit arg_end */
276 		if (pos + got >= arg_end) {
277 			int n = 0;
278 
279 			/*
280 			 * If we started before 'arg_end' but ended up
281 			 * at or after it, we start the NUL character
282 			 * check at arg_end-1 (where we expect the normal
283 			 * EOF to be).
284 			 *
285 			 * NOTE! This is smaller than 'got', because
286 			 * pos + got >= arg_end
287 			 */
288 			if (pos < arg_end)
289 				n = arg_end - pos - 1;
290 
291 			/* Cut off at first NUL after 'n' */
292 			got = n + strnlen(page+n, offset+got-n);
293 			if (got < offset)
294 				break;
295 			got -= offset;
296 
297 			/* Include the NUL if it existed */
298 			if (got < size)
299 				got++;
300 		}
301 
302 		got -= copy_to_user(buf, page+offset, got);
303 		if (unlikely(!got)) {
304 			if (!len)
305 				len = -EFAULT;
306 			break;
307 		}
308 		pos += got;
309 		buf += got;
310 		len += got;
311 		count -= got;
312 	}
313 
314 	free_page((unsigned long)page);
315 	return len;
316 }
317 
318 static ssize_t get_task_cmdline(struct task_struct *tsk, char __user *buf,
319 				size_t count, loff_t *pos)
320 {
321 	struct mm_struct *mm;
322 	ssize_t ret;
323 
324 	mm = get_task_mm(tsk);
325 	if (!mm)
326 		return 0;
327 
328 	ret = get_mm_cmdline(mm, buf, count, pos);
329 	mmput(mm);
330 	return ret;
331 }
332 
333 static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
334 				     size_t count, loff_t *pos)
335 {
336 	struct task_struct *tsk;
337 	ssize_t ret;
338 
339 	BUG_ON(*pos < 0);
340 
341 	tsk = get_proc_task(file_inode(file));
342 	if (!tsk)
343 		return -ESRCH;
344 	ret = get_task_cmdline(tsk, buf, count, pos);
345 	put_task_struct(tsk);
346 	if (ret > 0)
347 		*pos += ret;
348 	return ret;
349 }
350 
351 static const struct file_operations proc_pid_cmdline_ops = {
352 	.read	= proc_pid_cmdline_read,
353 	.llseek	= generic_file_llseek,
354 };
355 
356 #ifdef CONFIG_KALLSYMS
357 /*
358  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
359  * Returns the resolved symbol.  If that fails, simply return the address.
360  */
361 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
362 			  struct pid *pid, struct task_struct *task)
363 {
364 	unsigned long wchan;
365 	char symname[KSYM_NAME_LEN];
366 
367 	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
368 		goto print0;
369 
370 	wchan = get_wchan(task);
371 	if (wchan && !lookup_symbol_name(wchan, symname)) {
372 		seq_puts(m, symname);
373 		return 0;
374 	}
375 
376 print0:
377 	seq_putc(m, '0');
378 	return 0;
379 }
380 #endif /* CONFIG_KALLSYMS */
381 
382 static int lock_trace(struct task_struct *task)
383 {
384 	int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
385 	if (err)
386 		return err;
387 	if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
388 		mutex_unlock(&task->signal->cred_guard_mutex);
389 		return -EPERM;
390 	}
391 	return 0;
392 }
393 
394 static void unlock_trace(struct task_struct *task)
395 {
396 	mutex_unlock(&task->signal->cred_guard_mutex);
397 }
398 
399 #ifdef CONFIG_STACKTRACE
400 
401 #define MAX_STACK_TRACE_DEPTH	64
402 
403 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
404 			  struct pid *pid, struct task_struct *task)
405 {
406 	struct stack_trace trace;
407 	unsigned long *entries;
408 	int err;
409 
410 	/*
411 	 * The ability to racily run the kernel stack unwinder on a running task
412 	 * and then observe the unwinder output is scary; while it is useful for
413 	 * debugging kernel issues, it can also allow an attacker to leak kernel
414 	 * stack contents.
415 	 * Doing this in a manner that is at least safe from races would require
416 	 * some work to ensure that the remote task can not be scheduled; and
417 	 * even then, this would still expose the unwinder as local attack
418 	 * surface.
419 	 * Therefore, this interface is restricted to root.
420 	 */
421 	if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
422 		return -EACCES;
423 
424 	entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
425 				GFP_KERNEL);
426 	if (!entries)
427 		return -ENOMEM;
428 
429 	trace.nr_entries	= 0;
430 	trace.max_entries	= MAX_STACK_TRACE_DEPTH;
431 	trace.entries		= entries;
432 	trace.skip		= 0;
433 
434 	err = lock_trace(task);
435 	if (!err) {
436 		unsigned int i;
437 
438 		save_stack_trace_tsk(task, &trace);
439 
440 		for (i = 0; i < trace.nr_entries; i++) {
441 			seq_printf(m, "[<0>] %pB\n", (void *)entries[i]);
442 		}
443 		unlock_trace(task);
444 	}
445 	kfree(entries);
446 
447 	return err;
448 }
449 #endif
450 
451 #ifdef CONFIG_SCHED_INFO
452 /*
453  * Provides /proc/PID/schedstat
454  */
455 static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
456 			      struct pid *pid, struct task_struct *task)
457 {
458 	if (unlikely(!sched_info_on()))
459 		seq_printf(m, "0 0 0\n");
460 	else
461 		seq_printf(m, "%llu %llu %lu\n",
462 		   (unsigned long long)task->se.sum_exec_runtime,
463 		   (unsigned long long)task->sched_info.run_delay,
464 		   task->sched_info.pcount);
465 
466 	return 0;
467 }
468 #endif
469 
470 #ifdef CONFIG_LATENCYTOP
471 static int lstats_show_proc(struct seq_file *m, void *v)
472 {
473 	int i;
474 	struct inode *inode = m->private;
475 	struct task_struct *task = get_proc_task(inode);
476 
477 	if (!task)
478 		return -ESRCH;
479 	seq_puts(m, "Latency Top version : v0.1\n");
480 	for (i = 0; i < LT_SAVECOUNT; i++) {
481 		struct latency_record *lr = &task->latency_record[i];
482 		if (lr->backtrace[0]) {
483 			int q;
484 			seq_printf(m, "%i %li %li",
485 				   lr->count, lr->time, lr->max);
486 			for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
487 				unsigned long bt = lr->backtrace[q];
488 				if (!bt)
489 					break;
490 				if (bt == ULONG_MAX)
491 					break;
492 				seq_printf(m, " %ps", (void *)bt);
493 			}
494 			seq_putc(m, '\n');
495 		}
496 
497 	}
498 	put_task_struct(task);
499 	return 0;
500 }
501 
502 static int lstats_open(struct inode *inode, struct file *file)
503 {
504 	return single_open(file, lstats_show_proc, inode);
505 }
506 
507 static ssize_t lstats_write(struct file *file, const char __user *buf,
508 			    size_t count, loff_t *offs)
509 {
510 	struct task_struct *task = get_proc_task(file_inode(file));
511 
512 	if (!task)
513 		return -ESRCH;
514 	clear_all_latency_tracing(task);
515 	put_task_struct(task);
516 
517 	return count;
518 }
519 
520 static const struct file_operations proc_lstats_operations = {
521 	.open		= lstats_open,
522 	.read		= seq_read,
523 	.write		= lstats_write,
524 	.llseek		= seq_lseek,
525 	.release	= single_release,
526 };
527 
528 #endif
529 
530 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
531 			  struct pid *pid, struct task_struct *task)
532 {
533 	unsigned long totalpages = totalram_pages + total_swap_pages;
534 	unsigned long points = 0;
535 
536 	points = oom_badness(task, NULL, NULL, totalpages) *
537 					1000 / totalpages;
538 	seq_printf(m, "%lu\n", points);
539 
540 	return 0;
541 }
542 
543 struct limit_names {
544 	const char *name;
545 	const char *unit;
546 };
547 
548 static const struct limit_names lnames[RLIM_NLIMITS] = {
549 	[RLIMIT_CPU] = {"Max cpu time", "seconds"},
550 	[RLIMIT_FSIZE] = {"Max file size", "bytes"},
551 	[RLIMIT_DATA] = {"Max data size", "bytes"},
552 	[RLIMIT_STACK] = {"Max stack size", "bytes"},
553 	[RLIMIT_CORE] = {"Max core file size", "bytes"},
554 	[RLIMIT_RSS] = {"Max resident set", "bytes"},
555 	[RLIMIT_NPROC] = {"Max processes", "processes"},
556 	[RLIMIT_NOFILE] = {"Max open files", "files"},
557 	[RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
558 	[RLIMIT_AS] = {"Max address space", "bytes"},
559 	[RLIMIT_LOCKS] = {"Max file locks", "locks"},
560 	[RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
561 	[RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
562 	[RLIMIT_NICE] = {"Max nice priority", NULL},
563 	[RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
564 	[RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
565 };
566 
567 /* Display limits for a process */
568 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
569 			   struct pid *pid, struct task_struct *task)
570 {
571 	unsigned int i;
572 	unsigned long flags;
573 
574 	struct rlimit rlim[RLIM_NLIMITS];
575 
576 	if (!lock_task_sighand(task, &flags))
577 		return 0;
578 	memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
579 	unlock_task_sighand(task, &flags);
580 
581 	/*
582 	 * print the file header
583 	 */
584        seq_printf(m, "%-25s %-20s %-20s %-10s\n",
585 		  "Limit", "Soft Limit", "Hard Limit", "Units");
586 
587 	for (i = 0; i < RLIM_NLIMITS; i++) {
588 		if (rlim[i].rlim_cur == RLIM_INFINITY)
589 			seq_printf(m, "%-25s %-20s ",
590 				   lnames[i].name, "unlimited");
591 		else
592 			seq_printf(m, "%-25s %-20lu ",
593 				   lnames[i].name, rlim[i].rlim_cur);
594 
595 		if (rlim[i].rlim_max == RLIM_INFINITY)
596 			seq_printf(m, "%-20s ", "unlimited");
597 		else
598 			seq_printf(m, "%-20lu ", rlim[i].rlim_max);
599 
600 		if (lnames[i].unit)
601 			seq_printf(m, "%-10s\n", lnames[i].unit);
602 		else
603 			seq_putc(m, '\n');
604 	}
605 
606 	return 0;
607 }
608 
609 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
610 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
611 			    struct pid *pid, struct task_struct *task)
612 {
613 	long nr;
614 	unsigned long args[6], sp, pc;
615 	int res;
616 
617 	res = lock_trace(task);
618 	if (res)
619 		return res;
620 
621 	if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
622 		seq_puts(m, "running\n");
623 	else if (nr < 0)
624 		seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
625 	else
626 		seq_printf(m,
627 		       "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
628 		       nr,
629 		       args[0], args[1], args[2], args[3], args[4], args[5],
630 		       sp, pc);
631 	unlock_trace(task);
632 
633 	return 0;
634 }
635 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
636 
637 /************************************************************************/
638 /*                       Here the fs part begins                        */
639 /************************************************************************/
640 
641 /* permission checks */
642 static int proc_fd_access_allowed(struct inode *inode)
643 {
644 	struct task_struct *task;
645 	int allowed = 0;
646 	/* Allow access to a task's file descriptors if it is us or we
647 	 * may use ptrace attach to the process and find out that
648 	 * information.
649 	 */
650 	task = get_proc_task(inode);
651 	if (task) {
652 		allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
653 		put_task_struct(task);
654 	}
655 	return allowed;
656 }
657 
658 int proc_setattr(struct dentry *dentry, struct iattr *attr)
659 {
660 	int error;
661 	struct inode *inode = d_inode(dentry);
662 
663 	if (attr->ia_valid & ATTR_MODE)
664 		return -EPERM;
665 
666 	error = setattr_prepare(dentry, attr);
667 	if (error)
668 		return error;
669 
670 	setattr_copy(inode, attr);
671 	mark_inode_dirty(inode);
672 	return 0;
673 }
674 
675 /*
676  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
677  * or euid/egid (for hide_pid_min=2)?
678  */
679 static bool has_pid_permissions(struct pid_namespace *pid,
680 				 struct task_struct *task,
681 				 int hide_pid_min)
682 {
683 	if (pid->hide_pid < hide_pid_min)
684 		return true;
685 	if (in_group_p(pid->pid_gid))
686 		return true;
687 	return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
688 }
689 
690 
691 static int proc_pid_permission(struct inode *inode, int mask)
692 {
693 	struct pid_namespace *pid = proc_pid_ns(inode);
694 	struct task_struct *task;
695 	bool has_perms;
696 
697 	task = get_proc_task(inode);
698 	if (!task)
699 		return -ESRCH;
700 	has_perms = has_pid_permissions(pid, task, HIDEPID_NO_ACCESS);
701 	put_task_struct(task);
702 
703 	if (!has_perms) {
704 		if (pid->hide_pid == HIDEPID_INVISIBLE) {
705 			/*
706 			 * Let's make getdents(), stat(), and open()
707 			 * consistent with each other.  If a process
708 			 * may not stat() a file, it shouldn't be seen
709 			 * in procfs at all.
710 			 */
711 			return -ENOENT;
712 		}
713 
714 		return -EPERM;
715 	}
716 	return generic_permission(inode, mask);
717 }
718 
719 
720 
721 static const struct inode_operations proc_def_inode_operations = {
722 	.setattr	= proc_setattr,
723 };
724 
725 static int proc_single_show(struct seq_file *m, void *v)
726 {
727 	struct inode *inode = m->private;
728 	struct pid_namespace *ns = proc_pid_ns(inode);
729 	struct pid *pid = proc_pid(inode);
730 	struct task_struct *task;
731 	int ret;
732 
733 	task = get_pid_task(pid, PIDTYPE_PID);
734 	if (!task)
735 		return -ESRCH;
736 
737 	ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
738 
739 	put_task_struct(task);
740 	return ret;
741 }
742 
743 static int proc_single_open(struct inode *inode, struct file *filp)
744 {
745 	return single_open(filp, proc_single_show, inode);
746 }
747 
748 static const struct file_operations proc_single_file_operations = {
749 	.open		= proc_single_open,
750 	.read		= seq_read,
751 	.llseek		= seq_lseek,
752 	.release	= single_release,
753 };
754 
755 
756 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
757 {
758 	struct task_struct *task = get_proc_task(inode);
759 	struct mm_struct *mm = ERR_PTR(-ESRCH);
760 
761 	if (task) {
762 		mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
763 		put_task_struct(task);
764 
765 		if (!IS_ERR_OR_NULL(mm)) {
766 			/* ensure this mm_struct can't be freed */
767 			mmgrab(mm);
768 			/* but do not pin its memory */
769 			mmput(mm);
770 		}
771 	}
772 
773 	return mm;
774 }
775 
776 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
777 {
778 	struct mm_struct *mm = proc_mem_open(inode, mode);
779 
780 	if (IS_ERR(mm))
781 		return PTR_ERR(mm);
782 
783 	file->private_data = mm;
784 	return 0;
785 }
786 
787 static int mem_open(struct inode *inode, struct file *file)
788 {
789 	int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
790 
791 	/* OK to pass negative loff_t, we can catch out-of-range */
792 	file->f_mode |= FMODE_UNSIGNED_OFFSET;
793 
794 	return ret;
795 }
796 
797 static ssize_t mem_rw(struct file *file, char __user *buf,
798 			size_t count, loff_t *ppos, int write)
799 {
800 	struct mm_struct *mm = file->private_data;
801 	unsigned long addr = *ppos;
802 	ssize_t copied;
803 	char *page;
804 	unsigned int flags;
805 
806 	if (!mm)
807 		return 0;
808 
809 	page = (char *)__get_free_page(GFP_KERNEL);
810 	if (!page)
811 		return -ENOMEM;
812 
813 	copied = 0;
814 	if (!mmget_not_zero(mm))
815 		goto free;
816 
817 	flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
818 
819 	while (count > 0) {
820 		int this_len = min_t(int, count, PAGE_SIZE);
821 
822 		if (write && copy_from_user(page, buf, this_len)) {
823 			copied = -EFAULT;
824 			break;
825 		}
826 
827 		this_len = access_remote_vm(mm, addr, page, this_len, flags);
828 		if (!this_len) {
829 			if (!copied)
830 				copied = -EIO;
831 			break;
832 		}
833 
834 		if (!write && copy_to_user(buf, page, this_len)) {
835 			copied = -EFAULT;
836 			break;
837 		}
838 
839 		buf += this_len;
840 		addr += this_len;
841 		copied += this_len;
842 		count -= this_len;
843 	}
844 	*ppos = addr;
845 
846 	mmput(mm);
847 free:
848 	free_page((unsigned long) page);
849 	return copied;
850 }
851 
852 static ssize_t mem_read(struct file *file, char __user *buf,
853 			size_t count, loff_t *ppos)
854 {
855 	return mem_rw(file, buf, count, ppos, 0);
856 }
857 
858 static ssize_t mem_write(struct file *file, const char __user *buf,
859 			 size_t count, loff_t *ppos)
860 {
861 	return mem_rw(file, (char __user*)buf, count, ppos, 1);
862 }
863 
864 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
865 {
866 	switch (orig) {
867 	case 0:
868 		file->f_pos = offset;
869 		break;
870 	case 1:
871 		file->f_pos += offset;
872 		break;
873 	default:
874 		return -EINVAL;
875 	}
876 	force_successful_syscall_return();
877 	return file->f_pos;
878 }
879 
880 static int mem_release(struct inode *inode, struct file *file)
881 {
882 	struct mm_struct *mm = file->private_data;
883 	if (mm)
884 		mmdrop(mm);
885 	return 0;
886 }
887 
888 static const struct file_operations proc_mem_operations = {
889 	.llseek		= mem_lseek,
890 	.read		= mem_read,
891 	.write		= mem_write,
892 	.open		= mem_open,
893 	.release	= mem_release,
894 };
895 
896 static int environ_open(struct inode *inode, struct file *file)
897 {
898 	return __mem_open(inode, file, PTRACE_MODE_READ);
899 }
900 
901 static ssize_t environ_read(struct file *file, char __user *buf,
902 			size_t count, loff_t *ppos)
903 {
904 	char *page;
905 	unsigned long src = *ppos;
906 	int ret = 0;
907 	struct mm_struct *mm = file->private_data;
908 	unsigned long env_start, env_end;
909 
910 	/* Ensure the process spawned far enough to have an environment. */
911 	if (!mm || !mm->env_end)
912 		return 0;
913 
914 	page = (char *)__get_free_page(GFP_KERNEL);
915 	if (!page)
916 		return -ENOMEM;
917 
918 	ret = 0;
919 	if (!mmget_not_zero(mm))
920 		goto free;
921 
922 	spin_lock(&mm->arg_lock);
923 	env_start = mm->env_start;
924 	env_end = mm->env_end;
925 	spin_unlock(&mm->arg_lock);
926 
927 	while (count > 0) {
928 		size_t this_len, max_len;
929 		int retval;
930 
931 		if (src >= (env_end - env_start))
932 			break;
933 
934 		this_len = env_end - (env_start + src);
935 
936 		max_len = min_t(size_t, PAGE_SIZE, count);
937 		this_len = min(max_len, this_len);
938 
939 		retval = access_remote_vm(mm, (env_start + src), page, this_len, FOLL_ANON);
940 
941 		if (retval <= 0) {
942 			ret = retval;
943 			break;
944 		}
945 
946 		if (copy_to_user(buf, page, retval)) {
947 			ret = -EFAULT;
948 			break;
949 		}
950 
951 		ret += retval;
952 		src += retval;
953 		buf += retval;
954 		count -= retval;
955 	}
956 	*ppos = src;
957 	mmput(mm);
958 
959 free:
960 	free_page((unsigned long) page);
961 	return ret;
962 }
963 
964 static const struct file_operations proc_environ_operations = {
965 	.open		= environ_open,
966 	.read		= environ_read,
967 	.llseek		= generic_file_llseek,
968 	.release	= mem_release,
969 };
970 
971 static int auxv_open(struct inode *inode, struct file *file)
972 {
973 	return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
974 }
975 
976 static ssize_t auxv_read(struct file *file, char __user *buf,
977 			size_t count, loff_t *ppos)
978 {
979 	struct mm_struct *mm = file->private_data;
980 	unsigned int nwords = 0;
981 
982 	if (!mm)
983 		return 0;
984 	do {
985 		nwords += 2;
986 	} while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
987 	return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
988 				       nwords * sizeof(mm->saved_auxv[0]));
989 }
990 
991 static const struct file_operations proc_auxv_operations = {
992 	.open		= auxv_open,
993 	.read		= auxv_read,
994 	.llseek		= generic_file_llseek,
995 	.release	= mem_release,
996 };
997 
998 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
999 			    loff_t *ppos)
1000 {
1001 	struct task_struct *task = get_proc_task(file_inode(file));
1002 	char buffer[PROC_NUMBUF];
1003 	int oom_adj = OOM_ADJUST_MIN;
1004 	size_t len;
1005 
1006 	if (!task)
1007 		return -ESRCH;
1008 	if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1009 		oom_adj = OOM_ADJUST_MAX;
1010 	else
1011 		oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1012 			  OOM_SCORE_ADJ_MAX;
1013 	put_task_struct(task);
1014 	len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1015 	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1016 }
1017 
1018 static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1019 {
1020 	static DEFINE_MUTEX(oom_adj_mutex);
1021 	struct mm_struct *mm = NULL;
1022 	struct task_struct *task;
1023 	int err = 0;
1024 
1025 	task = get_proc_task(file_inode(file));
1026 	if (!task)
1027 		return -ESRCH;
1028 
1029 	mutex_lock(&oom_adj_mutex);
1030 	if (legacy) {
1031 		if (oom_adj < task->signal->oom_score_adj &&
1032 				!capable(CAP_SYS_RESOURCE)) {
1033 			err = -EACCES;
1034 			goto err_unlock;
1035 		}
1036 		/*
1037 		 * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1038 		 * /proc/pid/oom_score_adj instead.
1039 		 */
1040 		pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1041 			  current->comm, task_pid_nr(current), task_pid_nr(task),
1042 			  task_pid_nr(task));
1043 	} else {
1044 		if ((short)oom_adj < task->signal->oom_score_adj_min &&
1045 				!capable(CAP_SYS_RESOURCE)) {
1046 			err = -EACCES;
1047 			goto err_unlock;
1048 		}
1049 	}
1050 
1051 	/*
1052 	 * Make sure we will check other processes sharing the mm if this is
1053 	 * not vfrok which wants its own oom_score_adj.
1054 	 * pin the mm so it doesn't go away and get reused after task_unlock
1055 	 */
1056 	if (!task->vfork_done) {
1057 		struct task_struct *p = find_lock_task_mm(task);
1058 
1059 		if (p) {
1060 			if (atomic_read(&p->mm->mm_users) > 1) {
1061 				mm = p->mm;
1062 				mmgrab(mm);
1063 			}
1064 			task_unlock(p);
1065 		}
1066 	}
1067 
1068 	task->signal->oom_score_adj = oom_adj;
1069 	if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1070 		task->signal->oom_score_adj_min = (short)oom_adj;
1071 	trace_oom_score_adj_update(task);
1072 
1073 	if (mm) {
1074 		struct task_struct *p;
1075 
1076 		rcu_read_lock();
1077 		for_each_process(p) {
1078 			if (same_thread_group(task, p))
1079 				continue;
1080 
1081 			/* do not touch kernel threads or the global init */
1082 			if (p->flags & PF_KTHREAD || is_global_init(p))
1083 				continue;
1084 
1085 			task_lock(p);
1086 			if (!p->vfork_done && process_shares_mm(p, mm)) {
1087 				pr_info("updating oom_score_adj for %d (%s) from %d to %d because it shares mm with %d (%s). Report if this is unexpected.\n",
1088 						task_pid_nr(p), p->comm,
1089 						p->signal->oom_score_adj, oom_adj,
1090 						task_pid_nr(task), task->comm);
1091 				p->signal->oom_score_adj = oom_adj;
1092 				if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1093 					p->signal->oom_score_adj_min = (short)oom_adj;
1094 			}
1095 			task_unlock(p);
1096 		}
1097 		rcu_read_unlock();
1098 		mmdrop(mm);
1099 	}
1100 err_unlock:
1101 	mutex_unlock(&oom_adj_mutex);
1102 	put_task_struct(task);
1103 	return err;
1104 }
1105 
1106 /*
1107  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1108  * kernels.  The effective policy is defined by oom_score_adj, which has a
1109  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1110  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1111  * Processes that become oom disabled via oom_adj will still be oom disabled
1112  * with this implementation.
1113  *
1114  * oom_adj cannot be removed since existing userspace binaries use it.
1115  */
1116 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1117 			     size_t count, loff_t *ppos)
1118 {
1119 	char buffer[PROC_NUMBUF];
1120 	int oom_adj;
1121 	int err;
1122 
1123 	memset(buffer, 0, sizeof(buffer));
1124 	if (count > sizeof(buffer) - 1)
1125 		count = sizeof(buffer) - 1;
1126 	if (copy_from_user(buffer, buf, count)) {
1127 		err = -EFAULT;
1128 		goto out;
1129 	}
1130 
1131 	err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1132 	if (err)
1133 		goto out;
1134 	if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1135 	     oom_adj != OOM_DISABLE) {
1136 		err = -EINVAL;
1137 		goto out;
1138 	}
1139 
1140 	/*
1141 	 * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1142 	 * value is always attainable.
1143 	 */
1144 	if (oom_adj == OOM_ADJUST_MAX)
1145 		oom_adj = OOM_SCORE_ADJ_MAX;
1146 	else
1147 		oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1148 
1149 	err = __set_oom_adj(file, oom_adj, true);
1150 out:
1151 	return err < 0 ? err : count;
1152 }
1153 
1154 static const struct file_operations proc_oom_adj_operations = {
1155 	.read		= oom_adj_read,
1156 	.write		= oom_adj_write,
1157 	.llseek		= generic_file_llseek,
1158 };
1159 
1160 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1161 					size_t count, loff_t *ppos)
1162 {
1163 	struct task_struct *task = get_proc_task(file_inode(file));
1164 	char buffer[PROC_NUMBUF];
1165 	short oom_score_adj = OOM_SCORE_ADJ_MIN;
1166 	size_t len;
1167 
1168 	if (!task)
1169 		return -ESRCH;
1170 	oom_score_adj = task->signal->oom_score_adj;
1171 	put_task_struct(task);
1172 	len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1173 	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1174 }
1175 
1176 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1177 					size_t count, loff_t *ppos)
1178 {
1179 	char buffer[PROC_NUMBUF];
1180 	int oom_score_adj;
1181 	int err;
1182 
1183 	memset(buffer, 0, sizeof(buffer));
1184 	if (count > sizeof(buffer) - 1)
1185 		count = sizeof(buffer) - 1;
1186 	if (copy_from_user(buffer, buf, count)) {
1187 		err = -EFAULT;
1188 		goto out;
1189 	}
1190 
1191 	err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1192 	if (err)
1193 		goto out;
1194 	if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1195 			oom_score_adj > OOM_SCORE_ADJ_MAX) {
1196 		err = -EINVAL;
1197 		goto out;
1198 	}
1199 
1200 	err = __set_oom_adj(file, oom_score_adj, false);
1201 out:
1202 	return err < 0 ? err : count;
1203 }
1204 
1205 static const struct file_operations proc_oom_score_adj_operations = {
1206 	.read		= oom_score_adj_read,
1207 	.write		= oom_score_adj_write,
1208 	.llseek		= default_llseek,
1209 };
1210 
1211 #ifdef CONFIG_AUDITSYSCALL
1212 #define TMPBUFLEN 11
1213 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1214 				  size_t count, loff_t *ppos)
1215 {
1216 	struct inode * inode = file_inode(file);
1217 	struct task_struct *task = get_proc_task(inode);
1218 	ssize_t length;
1219 	char tmpbuf[TMPBUFLEN];
1220 
1221 	if (!task)
1222 		return -ESRCH;
1223 	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1224 			   from_kuid(file->f_cred->user_ns,
1225 				     audit_get_loginuid(task)));
1226 	put_task_struct(task);
1227 	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1228 }
1229 
1230 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1231 				   size_t count, loff_t *ppos)
1232 {
1233 	struct inode * inode = file_inode(file);
1234 	uid_t loginuid;
1235 	kuid_t kloginuid;
1236 	int rv;
1237 
1238 	rcu_read_lock();
1239 	if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1240 		rcu_read_unlock();
1241 		return -EPERM;
1242 	}
1243 	rcu_read_unlock();
1244 
1245 	if (*ppos != 0) {
1246 		/* No partial writes. */
1247 		return -EINVAL;
1248 	}
1249 
1250 	rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1251 	if (rv < 0)
1252 		return rv;
1253 
1254 	/* is userspace tring to explicitly UNSET the loginuid? */
1255 	if (loginuid == AUDIT_UID_UNSET) {
1256 		kloginuid = INVALID_UID;
1257 	} else {
1258 		kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1259 		if (!uid_valid(kloginuid))
1260 			return -EINVAL;
1261 	}
1262 
1263 	rv = audit_set_loginuid(kloginuid);
1264 	if (rv < 0)
1265 		return rv;
1266 	return count;
1267 }
1268 
1269 static const struct file_operations proc_loginuid_operations = {
1270 	.read		= proc_loginuid_read,
1271 	.write		= proc_loginuid_write,
1272 	.llseek		= generic_file_llseek,
1273 };
1274 
1275 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1276 				  size_t count, loff_t *ppos)
1277 {
1278 	struct inode * inode = file_inode(file);
1279 	struct task_struct *task = get_proc_task(inode);
1280 	ssize_t length;
1281 	char tmpbuf[TMPBUFLEN];
1282 
1283 	if (!task)
1284 		return -ESRCH;
1285 	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1286 				audit_get_sessionid(task));
1287 	put_task_struct(task);
1288 	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1289 }
1290 
1291 static const struct file_operations proc_sessionid_operations = {
1292 	.read		= proc_sessionid_read,
1293 	.llseek		= generic_file_llseek,
1294 };
1295 #endif
1296 
1297 #ifdef CONFIG_FAULT_INJECTION
1298 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1299 				      size_t count, loff_t *ppos)
1300 {
1301 	struct task_struct *task = get_proc_task(file_inode(file));
1302 	char buffer[PROC_NUMBUF];
1303 	size_t len;
1304 	int make_it_fail;
1305 
1306 	if (!task)
1307 		return -ESRCH;
1308 	make_it_fail = task->make_it_fail;
1309 	put_task_struct(task);
1310 
1311 	len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1312 
1313 	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1314 }
1315 
1316 static ssize_t proc_fault_inject_write(struct file * file,
1317 			const char __user * buf, size_t count, loff_t *ppos)
1318 {
1319 	struct task_struct *task;
1320 	char buffer[PROC_NUMBUF];
1321 	int make_it_fail;
1322 	int rv;
1323 
1324 	if (!capable(CAP_SYS_RESOURCE))
1325 		return -EPERM;
1326 	memset(buffer, 0, sizeof(buffer));
1327 	if (count > sizeof(buffer) - 1)
1328 		count = sizeof(buffer) - 1;
1329 	if (copy_from_user(buffer, buf, count))
1330 		return -EFAULT;
1331 	rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1332 	if (rv < 0)
1333 		return rv;
1334 	if (make_it_fail < 0 || make_it_fail > 1)
1335 		return -EINVAL;
1336 
1337 	task = get_proc_task(file_inode(file));
1338 	if (!task)
1339 		return -ESRCH;
1340 	task->make_it_fail = make_it_fail;
1341 	put_task_struct(task);
1342 
1343 	return count;
1344 }
1345 
1346 static const struct file_operations proc_fault_inject_operations = {
1347 	.read		= proc_fault_inject_read,
1348 	.write		= proc_fault_inject_write,
1349 	.llseek		= generic_file_llseek,
1350 };
1351 
1352 static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
1353 				   size_t count, loff_t *ppos)
1354 {
1355 	struct task_struct *task;
1356 	int err;
1357 	unsigned int n;
1358 
1359 	err = kstrtouint_from_user(buf, count, 0, &n);
1360 	if (err)
1361 		return err;
1362 
1363 	task = get_proc_task(file_inode(file));
1364 	if (!task)
1365 		return -ESRCH;
1366 	task->fail_nth = n;
1367 	put_task_struct(task);
1368 
1369 	return count;
1370 }
1371 
1372 static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
1373 				  size_t count, loff_t *ppos)
1374 {
1375 	struct task_struct *task;
1376 	char numbuf[PROC_NUMBUF];
1377 	ssize_t len;
1378 
1379 	task = get_proc_task(file_inode(file));
1380 	if (!task)
1381 		return -ESRCH;
1382 	len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
1383 	put_task_struct(task);
1384 	return simple_read_from_buffer(buf, count, ppos, numbuf, len);
1385 }
1386 
1387 static const struct file_operations proc_fail_nth_operations = {
1388 	.read		= proc_fail_nth_read,
1389 	.write		= proc_fail_nth_write,
1390 };
1391 #endif
1392 
1393 
1394 #ifdef CONFIG_SCHED_DEBUG
1395 /*
1396  * Print out various scheduling related per-task fields:
1397  */
1398 static int sched_show(struct seq_file *m, void *v)
1399 {
1400 	struct inode *inode = m->private;
1401 	struct pid_namespace *ns = proc_pid_ns(inode);
1402 	struct task_struct *p;
1403 
1404 	p = get_proc_task(inode);
1405 	if (!p)
1406 		return -ESRCH;
1407 	proc_sched_show_task(p, ns, m);
1408 
1409 	put_task_struct(p);
1410 
1411 	return 0;
1412 }
1413 
1414 static ssize_t
1415 sched_write(struct file *file, const char __user *buf,
1416 	    size_t count, loff_t *offset)
1417 {
1418 	struct inode *inode = file_inode(file);
1419 	struct task_struct *p;
1420 
1421 	p = get_proc_task(inode);
1422 	if (!p)
1423 		return -ESRCH;
1424 	proc_sched_set_task(p);
1425 
1426 	put_task_struct(p);
1427 
1428 	return count;
1429 }
1430 
1431 static int sched_open(struct inode *inode, struct file *filp)
1432 {
1433 	return single_open(filp, sched_show, inode);
1434 }
1435 
1436 static const struct file_operations proc_pid_sched_operations = {
1437 	.open		= sched_open,
1438 	.read		= seq_read,
1439 	.write		= sched_write,
1440 	.llseek		= seq_lseek,
1441 	.release	= single_release,
1442 };
1443 
1444 #endif
1445 
1446 #ifdef CONFIG_SCHED_AUTOGROUP
1447 /*
1448  * Print out autogroup related information:
1449  */
1450 static int sched_autogroup_show(struct seq_file *m, void *v)
1451 {
1452 	struct inode *inode = m->private;
1453 	struct task_struct *p;
1454 
1455 	p = get_proc_task(inode);
1456 	if (!p)
1457 		return -ESRCH;
1458 	proc_sched_autogroup_show_task(p, m);
1459 
1460 	put_task_struct(p);
1461 
1462 	return 0;
1463 }
1464 
1465 static ssize_t
1466 sched_autogroup_write(struct file *file, const char __user *buf,
1467 	    size_t count, loff_t *offset)
1468 {
1469 	struct inode *inode = file_inode(file);
1470 	struct task_struct *p;
1471 	char buffer[PROC_NUMBUF];
1472 	int nice;
1473 	int err;
1474 
1475 	memset(buffer, 0, sizeof(buffer));
1476 	if (count > sizeof(buffer) - 1)
1477 		count = sizeof(buffer) - 1;
1478 	if (copy_from_user(buffer, buf, count))
1479 		return -EFAULT;
1480 
1481 	err = kstrtoint(strstrip(buffer), 0, &nice);
1482 	if (err < 0)
1483 		return err;
1484 
1485 	p = get_proc_task(inode);
1486 	if (!p)
1487 		return -ESRCH;
1488 
1489 	err = proc_sched_autogroup_set_nice(p, nice);
1490 	if (err)
1491 		count = err;
1492 
1493 	put_task_struct(p);
1494 
1495 	return count;
1496 }
1497 
1498 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1499 {
1500 	int ret;
1501 
1502 	ret = single_open(filp, sched_autogroup_show, NULL);
1503 	if (!ret) {
1504 		struct seq_file *m = filp->private_data;
1505 
1506 		m->private = inode;
1507 	}
1508 	return ret;
1509 }
1510 
1511 static const struct file_operations proc_pid_sched_autogroup_operations = {
1512 	.open		= sched_autogroup_open,
1513 	.read		= seq_read,
1514 	.write		= sched_autogroup_write,
1515 	.llseek		= seq_lseek,
1516 	.release	= single_release,
1517 };
1518 
1519 #endif /* CONFIG_SCHED_AUTOGROUP */
1520 
1521 static ssize_t comm_write(struct file *file, const char __user *buf,
1522 				size_t count, loff_t *offset)
1523 {
1524 	struct inode *inode = file_inode(file);
1525 	struct task_struct *p;
1526 	char buffer[TASK_COMM_LEN];
1527 	const size_t maxlen = sizeof(buffer) - 1;
1528 
1529 	memset(buffer, 0, sizeof(buffer));
1530 	if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1531 		return -EFAULT;
1532 
1533 	p = get_proc_task(inode);
1534 	if (!p)
1535 		return -ESRCH;
1536 
1537 	if (same_thread_group(current, p))
1538 		set_task_comm(p, buffer);
1539 	else
1540 		count = -EINVAL;
1541 
1542 	put_task_struct(p);
1543 
1544 	return count;
1545 }
1546 
1547 static int comm_show(struct seq_file *m, void *v)
1548 {
1549 	struct inode *inode = m->private;
1550 	struct task_struct *p;
1551 
1552 	p = get_proc_task(inode);
1553 	if (!p)
1554 		return -ESRCH;
1555 
1556 	proc_task_name(m, p, false);
1557 	seq_putc(m, '\n');
1558 
1559 	put_task_struct(p);
1560 
1561 	return 0;
1562 }
1563 
1564 static int comm_open(struct inode *inode, struct file *filp)
1565 {
1566 	return single_open(filp, comm_show, inode);
1567 }
1568 
1569 static const struct file_operations proc_pid_set_comm_operations = {
1570 	.open		= comm_open,
1571 	.read		= seq_read,
1572 	.write		= comm_write,
1573 	.llseek		= seq_lseek,
1574 	.release	= single_release,
1575 };
1576 
1577 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1578 {
1579 	struct task_struct *task;
1580 	struct file *exe_file;
1581 
1582 	task = get_proc_task(d_inode(dentry));
1583 	if (!task)
1584 		return -ENOENT;
1585 	exe_file = get_task_exe_file(task);
1586 	put_task_struct(task);
1587 	if (exe_file) {
1588 		*exe_path = exe_file->f_path;
1589 		path_get(&exe_file->f_path);
1590 		fput(exe_file);
1591 		return 0;
1592 	} else
1593 		return -ENOENT;
1594 }
1595 
1596 static const char *proc_pid_get_link(struct dentry *dentry,
1597 				     struct inode *inode,
1598 				     struct delayed_call *done)
1599 {
1600 	struct path path;
1601 	int error = -EACCES;
1602 
1603 	if (!dentry)
1604 		return ERR_PTR(-ECHILD);
1605 
1606 	/* Are we allowed to snoop on the tasks file descriptors? */
1607 	if (!proc_fd_access_allowed(inode))
1608 		goto out;
1609 
1610 	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1611 	if (error)
1612 		goto out;
1613 
1614 	nd_jump_link(&path);
1615 	return NULL;
1616 out:
1617 	return ERR_PTR(error);
1618 }
1619 
1620 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1621 {
1622 	char *tmp = (char *)__get_free_page(GFP_KERNEL);
1623 	char *pathname;
1624 	int len;
1625 
1626 	if (!tmp)
1627 		return -ENOMEM;
1628 
1629 	pathname = d_path(path, tmp, PAGE_SIZE);
1630 	len = PTR_ERR(pathname);
1631 	if (IS_ERR(pathname))
1632 		goto out;
1633 	len = tmp + PAGE_SIZE - 1 - pathname;
1634 
1635 	if (len > buflen)
1636 		len = buflen;
1637 	if (copy_to_user(buffer, pathname, len))
1638 		len = -EFAULT;
1639  out:
1640 	free_page((unsigned long)tmp);
1641 	return len;
1642 }
1643 
1644 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1645 {
1646 	int error = -EACCES;
1647 	struct inode *inode = d_inode(dentry);
1648 	struct path path;
1649 
1650 	/* Are we allowed to snoop on the tasks file descriptors? */
1651 	if (!proc_fd_access_allowed(inode))
1652 		goto out;
1653 
1654 	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1655 	if (error)
1656 		goto out;
1657 
1658 	error = do_proc_readlink(&path, buffer, buflen);
1659 	path_put(&path);
1660 out:
1661 	return error;
1662 }
1663 
1664 const struct inode_operations proc_pid_link_inode_operations = {
1665 	.readlink	= proc_pid_readlink,
1666 	.get_link	= proc_pid_get_link,
1667 	.setattr	= proc_setattr,
1668 };
1669 
1670 
1671 /* building an inode */
1672 
1673 void task_dump_owner(struct task_struct *task, umode_t mode,
1674 		     kuid_t *ruid, kgid_t *rgid)
1675 {
1676 	/* Depending on the state of dumpable compute who should own a
1677 	 * proc file for a task.
1678 	 */
1679 	const struct cred *cred;
1680 	kuid_t uid;
1681 	kgid_t gid;
1682 
1683 	if (unlikely(task->flags & PF_KTHREAD)) {
1684 		*ruid = GLOBAL_ROOT_UID;
1685 		*rgid = GLOBAL_ROOT_GID;
1686 		return;
1687 	}
1688 
1689 	/* Default to the tasks effective ownership */
1690 	rcu_read_lock();
1691 	cred = __task_cred(task);
1692 	uid = cred->euid;
1693 	gid = cred->egid;
1694 	rcu_read_unlock();
1695 
1696 	/*
1697 	 * Before the /proc/pid/status file was created the only way to read
1698 	 * the effective uid of a /process was to stat /proc/pid.  Reading
1699 	 * /proc/pid/status is slow enough that procps and other packages
1700 	 * kept stating /proc/pid.  To keep the rules in /proc simple I have
1701 	 * made this apply to all per process world readable and executable
1702 	 * directories.
1703 	 */
1704 	if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
1705 		struct mm_struct *mm;
1706 		task_lock(task);
1707 		mm = task->mm;
1708 		/* Make non-dumpable tasks owned by some root */
1709 		if (mm) {
1710 			if (get_dumpable(mm) != SUID_DUMP_USER) {
1711 				struct user_namespace *user_ns = mm->user_ns;
1712 
1713 				uid = make_kuid(user_ns, 0);
1714 				if (!uid_valid(uid))
1715 					uid = GLOBAL_ROOT_UID;
1716 
1717 				gid = make_kgid(user_ns, 0);
1718 				if (!gid_valid(gid))
1719 					gid = GLOBAL_ROOT_GID;
1720 			}
1721 		} else {
1722 			uid = GLOBAL_ROOT_UID;
1723 			gid = GLOBAL_ROOT_GID;
1724 		}
1725 		task_unlock(task);
1726 	}
1727 	*ruid = uid;
1728 	*rgid = gid;
1729 }
1730 
1731 struct inode *proc_pid_make_inode(struct super_block * sb,
1732 				  struct task_struct *task, umode_t mode)
1733 {
1734 	struct inode * inode;
1735 	struct proc_inode *ei;
1736 
1737 	/* We need a new inode */
1738 
1739 	inode = new_inode(sb);
1740 	if (!inode)
1741 		goto out;
1742 
1743 	/* Common stuff */
1744 	ei = PROC_I(inode);
1745 	inode->i_mode = mode;
1746 	inode->i_ino = get_next_ino();
1747 	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1748 	inode->i_op = &proc_def_inode_operations;
1749 
1750 	/*
1751 	 * grab the reference to task.
1752 	 */
1753 	ei->pid = get_task_pid(task, PIDTYPE_PID);
1754 	if (!ei->pid)
1755 		goto out_unlock;
1756 
1757 	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1758 	security_task_to_inode(task, inode);
1759 
1760 out:
1761 	return inode;
1762 
1763 out_unlock:
1764 	iput(inode);
1765 	return NULL;
1766 }
1767 
1768 int pid_getattr(const struct path *path, struct kstat *stat,
1769 		u32 request_mask, unsigned int query_flags)
1770 {
1771 	struct inode *inode = d_inode(path->dentry);
1772 	struct pid_namespace *pid = proc_pid_ns(inode);
1773 	struct task_struct *task;
1774 
1775 	generic_fillattr(inode, stat);
1776 
1777 	stat->uid = GLOBAL_ROOT_UID;
1778 	stat->gid = GLOBAL_ROOT_GID;
1779 	rcu_read_lock();
1780 	task = pid_task(proc_pid(inode), PIDTYPE_PID);
1781 	if (task) {
1782 		if (!has_pid_permissions(pid, task, HIDEPID_INVISIBLE)) {
1783 			rcu_read_unlock();
1784 			/*
1785 			 * This doesn't prevent learning whether PID exists,
1786 			 * it only makes getattr() consistent with readdir().
1787 			 */
1788 			return -ENOENT;
1789 		}
1790 		task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
1791 	}
1792 	rcu_read_unlock();
1793 	return 0;
1794 }
1795 
1796 /* dentry stuff */
1797 
1798 /*
1799  * Set <pid>/... inode ownership (can change due to setuid(), etc.)
1800  */
1801 void pid_update_inode(struct task_struct *task, struct inode *inode)
1802 {
1803 	task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
1804 
1805 	inode->i_mode &= ~(S_ISUID | S_ISGID);
1806 	security_task_to_inode(task, inode);
1807 }
1808 
1809 /*
1810  * Rewrite the inode's ownerships here because the owning task may have
1811  * performed a setuid(), etc.
1812  *
1813  */
1814 static int pid_revalidate(struct dentry *dentry, unsigned int flags)
1815 {
1816 	struct inode *inode;
1817 	struct task_struct *task;
1818 
1819 	if (flags & LOOKUP_RCU)
1820 		return -ECHILD;
1821 
1822 	inode = d_inode(dentry);
1823 	task = get_proc_task(inode);
1824 
1825 	if (task) {
1826 		pid_update_inode(task, inode);
1827 		put_task_struct(task);
1828 		return 1;
1829 	}
1830 	return 0;
1831 }
1832 
1833 static inline bool proc_inode_is_dead(struct inode *inode)
1834 {
1835 	return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1836 }
1837 
1838 int pid_delete_dentry(const struct dentry *dentry)
1839 {
1840 	/* Is the task we represent dead?
1841 	 * If so, then don't put the dentry on the lru list,
1842 	 * kill it immediately.
1843 	 */
1844 	return proc_inode_is_dead(d_inode(dentry));
1845 }
1846 
1847 const struct dentry_operations pid_dentry_operations =
1848 {
1849 	.d_revalidate	= pid_revalidate,
1850 	.d_delete	= pid_delete_dentry,
1851 };
1852 
1853 /* Lookups */
1854 
1855 /*
1856  * Fill a directory entry.
1857  *
1858  * If possible create the dcache entry and derive our inode number and
1859  * file type from dcache entry.
1860  *
1861  * Since all of the proc inode numbers are dynamically generated, the inode
1862  * numbers do not exist until the inode is cache.  This means creating the
1863  * the dcache entry in readdir is necessary to keep the inode numbers
1864  * reported by readdir in sync with the inode numbers reported
1865  * by stat.
1866  */
1867 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1868 	const char *name, unsigned int len,
1869 	instantiate_t instantiate, struct task_struct *task, const void *ptr)
1870 {
1871 	struct dentry *child, *dir = file->f_path.dentry;
1872 	struct qstr qname = QSTR_INIT(name, len);
1873 	struct inode *inode;
1874 	unsigned type = DT_UNKNOWN;
1875 	ino_t ino = 1;
1876 
1877 	child = d_hash_and_lookup(dir, &qname);
1878 	if (!child) {
1879 		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1880 		child = d_alloc_parallel(dir, &qname, &wq);
1881 		if (IS_ERR(child))
1882 			goto end_instantiate;
1883 		if (d_in_lookup(child)) {
1884 			struct dentry *res;
1885 			res = instantiate(child, task, ptr);
1886 			d_lookup_done(child);
1887 			if (unlikely(res)) {
1888 				dput(child);
1889 				child = res;
1890 				if (IS_ERR(child))
1891 					goto end_instantiate;
1892 			}
1893 		}
1894 	}
1895 	inode = d_inode(child);
1896 	ino = inode->i_ino;
1897 	type = inode->i_mode >> 12;
1898 	dput(child);
1899 end_instantiate:
1900 	return dir_emit(ctx, name, len, ino, type);
1901 }
1902 
1903 /*
1904  * dname_to_vma_addr - maps a dentry name into two unsigned longs
1905  * which represent vma start and end addresses.
1906  */
1907 static int dname_to_vma_addr(struct dentry *dentry,
1908 			     unsigned long *start, unsigned long *end)
1909 {
1910 	const char *str = dentry->d_name.name;
1911 	unsigned long long sval, eval;
1912 	unsigned int len;
1913 
1914 	if (str[0] == '0' && str[1] != '-')
1915 		return -EINVAL;
1916 	len = _parse_integer(str, 16, &sval);
1917 	if (len & KSTRTOX_OVERFLOW)
1918 		return -EINVAL;
1919 	if (sval != (unsigned long)sval)
1920 		return -EINVAL;
1921 	str += len;
1922 
1923 	if (*str != '-')
1924 		return -EINVAL;
1925 	str++;
1926 
1927 	if (str[0] == '0' && str[1])
1928 		return -EINVAL;
1929 	len = _parse_integer(str, 16, &eval);
1930 	if (len & KSTRTOX_OVERFLOW)
1931 		return -EINVAL;
1932 	if (eval != (unsigned long)eval)
1933 		return -EINVAL;
1934 	str += len;
1935 
1936 	if (*str != '\0')
1937 		return -EINVAL;
1938 
1939 	*start = sval;
1940 	*end = eval;
1941 
1942 	return 0;
1943 }
1944 
1945 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1946 {
1947 	unsigned long vm_start, vm_end;
1948 	bool exact_vma_exists = false;
1949 	struct mm_struct *mm = NULL;
1950 	struct task_struct *task;
1951 	struct inode *inode;
1952 	int status = 0;
1953 
1954 	if (flags & LOOKUP_RCU)
1955 		return -ECHILD;
1956 
1957 	inode = d_inode(dentry);
1958 	task = get_proc_task(inode);
1959 	if (!task)
1960 		goto out_notask;
1961 
1962 	mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1963 	if (IS_ERR_OR_NULL(mm))
1964 		goto out;
1965 
1966 	if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1967 		down_read(&mm->mmap_sem);
1968 		exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1969 		up_read(&mm->mmap_sem);
1970 	}
1971 
1972 	mmput(mm);
1973 
1974 	if (exact_vma_exists) {
1975 		task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1976 
1977 		security_task_to_inode(task, inode);
1978 		status = 1;
1979 	}
1980 
1981 out:
1982 	put_task_struct(task);
1983 
1984 out_notask:
1985 	return status;
1986 }
1987 
1988 static const struct dentry_operations tid_map_files_dentry_operations = {
1989 	.d_revalidate	= map_files_d_revalidate,
1990 	.d_delete	= pid_delete_dentry,
1991 };
1992 
1993 static int map_files_get_link(struct dentry *dentry, struct path *path)
1994 {
1995 	unsigned long vm_start, vm_end;
1996 	struct vm_area_struct *vma;
1997 	struct task_struct *task;
1998 	struct mm_struct *mm;
1999 	int rc;
2000 
2001 	rc = -ENOENT;
2002 	task = get_proc_task(d_inode(dentry));
2003 	if (!task)
2004 		goto out;
2005 
2006 	mm = get_task_mm(task);
2007 	put_task_struct(task);
2008 	if (!mm)
2009 		goto out;
2010 
2011 	rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
2012 	if (rc)
2013 		goto out_mmput;
2014 
2015 	rc = -ENOENT;
2016 	down_read(&mm->mmap_sem);
2017 	vma = find_exact_vma(mm, vm_start, vm_end);
2018 	if (vma && vma->vm_file) {
2019 		*path = vma->vm_file->f_path;
2020 		path_get(path);
2021 		rc = 0;
2022 	}
2023 	up_read(&mm->mmap_sem);
2024 
2025 out_mmput:
2026 	mmput(mm);
2027 out:
2028 	return rc;
2029 }
2030 
2031 struct map_files_info {
2032 	unsigned long	start;
2033 	unsigned long	end;
2034 	fmode_t		mode;
2035 };
2036 
2037 /*
2038  * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
2039  * symlinks may be used to bypass permissions on ancestor directories in the
2040  * path to the file in question.
2041  */
2042 static const char *
2043 proc_map_files_get_link(struct dentry *dentry,
2044 			struct inode *inode,
2045 		        struct delayed_call *done)
2046 {
2047 	if (!capable(CAP_SYS_ADMIN))
2048 		return ERR_PTR(-EPERM);
2049 
2050 	return proc_pid_get_link(dentry, inode, done);
2051 }
2052 
2053 /*
2054  * Identical to proc_pid_link_inode_operations except for get_link()
2055  */
2056 static const struct inode_operations proc_map_files_link_inode_operations = {
2057 	.readlink	= proc_pid_readlink,
2058 	.get_link	= proc_map_files_get_link,
2059 	.setattr	= proc_setattr,
2060 };
2061 
2062 static struct dentry *
2063 proc_map_files_instantiate(struct dentry *dentry,
2064 			   struct task_struct *task, const void *ptr)
2065 {
2066 	fmode_t mode = (fmode_t)(unsigned long)ptr;
2067 	struct proc_inode *ei;
2068 	struct inode *inode;
2069 
2070 	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
2071 				    ((mode & FMODE_READ ) ? S_IRUSR : 0) |
2072 				    ((mode & FMODE_WRITE) ? S_IWUSR : 0));
2073 	if (!inode)
2074 		return ERR_PTR(-ENOENT);
2075 
2076 	ei = PROC_I(inode);
2077 	ei->op.proc_get_link = map_files_get_link;
2078 
2079 	inode->i_op = &proc_map_files_link_inode_operations;
2080 	inode->i_size = 64;
2081 
2082 	d_set_d_op(dentry, &tid_map_files_dentry_operations);
2083 	return d_splice_alias(inode, dentry);
2084 }
2085 
2086 static struct dentry *proc_map_files_lookup(struct inode *dir,
2087 		struct dentry *dentry, unsigned int flags)
2088 {
2089 	unsigned long vm_start, vm_end;
2090 	struct vm_area_struct *vma;
2091 	struct task_struct *task;
2092 	struct dentry *result;
2093 	struct mm_struct *mm;
2094 
2095 	result = ERR_PTR(-ENOENT);
2096 	task = get_proc_task(dir);
2097 	if (!task)
2098 		goto out;
2099 
2100 	result = ERR_PTR(-EACCES);
2101 	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2102 		goto out_put_task;
2103 
2104 	result = ERR_PTR(-ENOENT);
2105 	if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2106 		goto out_put_task;
2107 
2108 	mm = get_task_mm(task);
2109 	if (!mm)
2110 		goto out_put_task;
2111 
2112 	down_read(&mm->mmap_sem);
2113 	vma = find_exact_vma(mm, vm_start, vm_end);
2114 	if (!vma)
2115 		goto out_no_vma;
2116 
2117 	if (vma->vm_file)
2118 		result = proc_map_files_instantiate(dentry, task,
2119 				(void *)(unsigned long)vma->vm_file->f_mode);
2120 
2121 out_no_vma:
2122 	up_read(&mm->mmap_sem);
2123 	mmput(mm);
2124 out_put_task:
2125 	put_task_struct(task);
2126 out:
2127 	return result;
2128 }
2129 
2130 static const struct inode_operations proc_map_files_inode_operations = {
2131 	.lookup		= proc_map_files_lookup,
2132 	.permission	= proc_fd_permission,
2133 	.setattr	= proc_setattr,
2134 };
2135 
2136 static int
2137 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2138 {
2139 	struct vm_area_struct *vma;
2140 	struct task_struct *task;
2141 	struct mm_struct *mm;
2142 	unsigned long nr_files, pos, i;
2143 	struct flex_array *fa = NULL;
2144 	struct map_files_info info;
2145 	struct map_files_info *p;
2146 	int ret;
2147 
2148 	ret = -ENOENT;
2149 	task = get_proc_task(file_inode(file));
2150 	if (!task)
2151 		goto out;
2152 
2153 	ret = -EACCES;
2154 	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2155 		goto out_put_task;
2156 
2157 	ret = 0;
2158 	if (!dir_emit_dots(file, ctx))
2159 		goto out_put_task;
2160 
2161 	mm = get_task_mm(task);
2162 	if (!mm)
2163 		goto out_put_task;
2164 	down_read(&mm->mmap_sem);
2165 
2166 	nr_files = 0;
2167 
2168 	/*
2169 	 * We need two passes here:
2170 	 *
2171 	 *  1) Collect vmas of mapped files with mmap_sem taken
2172 	 *  2) Release mmap_sem and instantiate entries
2173 	 *
2174 	 * otherwise we get lockdep complained, since filldir()
2175 	 * routine might require mmap_sem taken in might_fault().
2176 	 */
2177 
2178 	for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2179 		if (vma->vm_file && ++pos > ctx->pos)
2180 			nr_files++;
2181 	}
2182 
2183 	if (nr_files) {
2184 		fa = flex_array_alloc(sizeof(info), nr_files,
2185 					GFP_KERNEL);
2186 		if (!fa || flex_array_prealloc(fa, 0, nr_files,
2187 						GFP_KERNEL)) {
2188 			ret = -ENOMEM;
2189 			if (fa)
2190 				flex_array_free(fa);
2191 			up_read(&mm->mmap_sem);
2192 			mmput(mm);
2193 			goto out_put_task;
2194 		}
2195 		for (i = 0, vma = mm->mmap, pos = 2; vma;
2196 				vma = vma->vm_next) {
2197 			if (!vma->vm_file)
2198 				continue;
2199 			if (++pos <= ctx->pos)
2200 				continue;
2201 
2202 			info.start = vma->vm_start;
2203 			info.end = vma->vm_end;
2204 			info.mode = vma->vm_file->f_mode;
2205 			if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2206 				BUG();
2207 		}
2208 	}
2209 	up_read(&mm->mmap_sem);
2210 	mmput(mm);
2211 
2212 	for (i = 0; i < nr_files; i++) {
2213 		char buf[4 * sizeof(long) + 2];	/* max: %lx-%lx\0 */
2214 		unsigned int len;
2215 
2216 		p = flex_array_get(fa, i);
2217 		len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
2218 		if (!proc_fill_cache(file, ctx,
2219 				      buf, len,
2220 				      proc_map_files_instantiate,
2221 				      task,
2222 				      (void *)(unsigned long)p->mode))
2223 			break;
2224 		ctx->pos++;
2225 	}
2226 	if (fa)
2227 		flex_array_free(fa);
2228 
2229 out_put_task:
2230 	put_task_struct(task);
2231 out:
2232 	return ret;
2233 }
2234 
2235 static const struct file_operations proc_map_files_operations = {
2236 	.read		= generic_read_dir,
2237 	.iterate_shared	= proc_map_files_readdir,
2238 	.llseek		= generic_file_llseek,
2239 };
2240 
2241 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2242 struct timers_private {
2243 	struct pid *pid;
2244 	struct task_struct *task;
2245 	struct sighand_struct *sighand;
2246 	struct pid_namespace *ns;
2247 	unsigned long flags;
2248 };
2249 
2250 static void *timers_start(struct seq_file *m, loff_t *pos)
2251 {
2252 	struct timers_private *tp = m->private;
2253 
2254 	tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2255 	if (!tp->task)
2256 		return ERR_PTR(-ESRCH);
2257 
2258 	tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2259 	if (!tp->sighand)
2260 		return ERR_PTR(-ESRCH);
2261 
2262 	return seq_list_start(&tp->task->signal->posix_timers, *pos);
2263 }
2264 
2265 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2266 {
2267 	struct timers_private *tp = m->private;
2268 	return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2269 }
2270 
2271 static void timers_stop(struct seq_file *m, void *v)
2272 {
2273 	struct timers_private *tp = m->private;
2274 
2275 	if (tp->sighand) {
2276 		unlock_task_sighand(tp->task, &tp->flags);
2277 		tp->sighand = NULL;
2278 	}
2279 
2280 	if (tp->task) {
2281 		put_task_struct(tp->task);
2282 		tp->task = NULL;
2283 	}
2284 }
2285 
2286 static int show_timer(struct seq_file *m, void *v)
2287 {
2288 	struct k_itimer *timer;
2289 	struct timers_private *tp = m->private;
2290 	int notify;
2291 	static const char * const nstr[] = {
2292 		[SIGEV_SIGNAL] = "signal",
2293 		[SIGEV_NONE] = "none",
2294 		[SIGEV_THREAD] = "thread",
2295 	};
2296 
2297 	timer = list_entry((struct list_head *)v, struct k_itimer, list);
2298 	notify = timer->it_sigev_notify;
2299 
2300 	seq_printf(m, "ID: %d\n", timer->it_id);
2301 	seq_printf(m, "signal: %d/%px\n",
2302 		   timer->sigq->info.si_signo,
2303 		   timer->sigq->info.si_value.sival_ptr);
2304 	seq_printf(m, "notify: %s/%s.%d\n",
2305 		   nstr[notify & ~SIGEV_THREAD_ID],
2306 		   (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2307 		   pid_nr_ns(timer->it_pid, tp->ns));
2308 	seq_printf(m, "ClockID: %d\n", timer->it_clock);
2309 
2310 	return 0;
2311 }
2312 
2313 static const struct seq_operations proc_timers_seq_ops = {
2314 	.start	= timers_start,
2315 	.next	= timers_next,
2316 	.stop	= timers_stop,
2317 	.show	= show_timer,
2318 };
2319 
2320 static int proc_timers_open(struct inode *inode, struct file *file)
2321 {
2322 	struct timers_private *tp;
2323 
2324 	tp = __seq_open_private(file, &proc_timers_seq_ops,
2325 			sizeof(struct timers_private));
2326 	if (!tp)
2327 		return -ENOMEM;
2328 
2329 	tp->pid = proc_pid(inode);
2330 	tp->ns = proc_pid_ns(inode);
2331 	return 0;
2332 }
2333 
2334 static const struct file_operations proc_timers_operations = {
2335 	.open		= proc_timers_open,
2336 	.read		= seq_read,
2337 	.llseek		= seq_lseek,
2338 	.release	= seq_release_private,
2339 };
2340 #endif
2341 
2342 static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2343 					size_t count, loff_t *offset)
2344 {
2345 	struct inode *inode = file_inode(file);
2346 	struct task_struct *p;
2347 	u64 slack_ns;
2348 	int err;
2349 
2350 	err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2351 	if (err < 0)
2352 		return err;
2353 
2354 	p = get_proc_task(inode);
2355 	if (!p)
2356 		return -ESRCH;
2357 
2358 	if (p != current) {
2359 		if (!capable(CAP_SYS_NICE)) {
2360 			count = -EPERM;
2361 			goto out;
2362 		}
2363 
2364 		err = security_task_setscheduler(p);
2365 		if (err) {
2366 			count = err;
2367 			goto out;
2368 		}
2369 	}
2370 
2371 	task_lock(p);
2372 	if (slack_ns == 0)
2373 		p->timer_slack_ns = p->default_timer_slack_ns;
2374 	else
2375 		p->timer_slack_ns = slack_ns;
2376 	task_unlock(p);
2377 
2378 out:
2379 	put_task_struct(p);
2380 
2381 	return count;
2382 }
2383 
2384 static int timerslack_ns_show(struct seq_file *m, void *v)
2385 {
2386 	struct inode *inode = m->private;
2387 	struct task_struct *p;
2388 	int err = 0;
2389 
2390 	p = get_proc_task(inode);
2391 	if (!p)
2392 		return -ESRCH;
2393 
2394 	if (p != current) {
2395 
2396 		if (!capable(CAP_SYS_NICE)) {
2397 			err = -EPERM;
2398 			goto out;
2399 		}
2400 		err = security_task_getscheduler(p);
2401 		if (err)
2402 			goto out;
2403 	}
2404 
2405 	task_lock(p);
2406 	seq_printf(m, "%llu\n", p->timer_slack_ns);
2407 	task_unlock(p);
2408 
2409 out:
2410 	put_task_struct(p);
2411 
2412 	return err;
2413 }
2414 
2415 static int timerslack_ns_open(struct inode *inode, struct file *filp)
2416 {
2417 	return single_open(filp, timerslack_ns_show, inode);
2418 }
2419 
2420 static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2421 	.open		= timerslack_ns_open,
2422 	.read		= seq_read,
2423 	.write		= timerslack_ns_write,
2424 	.llseek		= seq_lseek,
2425 	.release	= single_release,
2426 };
2427 
2428 static struct dentry *proc_pident_instantiate(struct dentry *dentry,
2429 	struct task_struct *task, const void *ptr)
2430 {
2431 	const struct pid_entry *p = ptr;
2432 	struct inode *inode;
2433 	struct proc_inode *ei;
2434 
2435 	inode = proc_pid_make_inode(dentry->d_sb, task, p->mode);
2436 	if (!inode)
2437 		return ERR_PTR(-ENOENT);
2438 
2439 	ei = PROC_I(inode);
2440 	if (S_ISDIR(inode->i_mode))
2441 		set_nlink(inode, 2);	/* Use getattr to fix if necessary */
2442 	if (p->iop)
2443 		inode->i_op = p->iop;
2444 	if (p->fop)
2445 		inode->i_fop = p->fop;
2446 	ei->op = p->op;
2447 	pid_update_inode(task, inode);
2448 	d_set_d_op(dentry, &pid_dentry_operations);
2449 	return d_splice_alias(inode, dentry);
2450 }
2451 
2452 static struct dentry *proc_pident_lookup(struct inode *dir,
2453 					 struct dentry *dentry,
2454 					 const struct pid_entry *ents,
2455 					 unsigned int nents)
2456 {
2457 	struct task_struct *task = get_proc_task(dir);
2458 	const struct pid_entry *p, *last;
2459 	struct dentry *res = ERR_PTR(-ENOENT);
2460 
2461 	if (!task)
2462 		goto out_no_task;
2463 
2464 	/*
2465 	 * Yes, it does not scale. And it should not. Don't add
2466 	 * new entries into /proc/<tgid>/ without very good reasons.
2467 	 */
2468 	last = &ents[nents];
2469 	for (p = ents; p < last; p++) {
2470 		if (p->len != dentry->d_name.len)
2471 			continue;
2472 		if (!memcmp(dentry->d_name.name, p->name, p->len)) {
2473 			res = proc_pident_instantiate(dentry, task, p);
2474 			break;
2475 		}
2476 	}
2477 	put_task_struct(task);
2478 out_no_task:
2479 	return res;
2480 }
2481 
2482 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2483 		const struct pid_entry *ents, unsigned int nents)
2484 {
2485 	struct task_struct *task = get_proc_task(file_inode(file));
2486 	const struct pid_entry *p;
2487 
2488 	if (!task)
2489 		return -ENOENT;
2490 
2491 	if (!dir_emit_dots(file, ctx))
2492 		goto out;
2493 
2494 	if (ctx->pos >= nents + 2)
2495 		goto out;
2496 
2497 	for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
2498 		if (!proc_fill_cache(file, ctx, p->name, p->len,
2499 				proc_pident_instantiate, task, p))
2500 			break;
2501 		ctx->pos++;
2502 	}
2503 out:
2504 	put_task_struct(task);
2505 	return 0;
2506 }
2507 
2508 #ifdef CONFIG_SECURITY
2509 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2510 				  size_t count, loff_t *ppos)
2511 {
2512 	struct inode * inode = file_inode(file);
2513 	char *p = NULL;
2514 	ssize_t length;
2515 	struct task_struct *task = get_proc_task(inode);
2516 
2517 	if (!task)
2518 		return -ESRCH;
2519 
2520 	length = security_getprocattr(task,
2521 				      (char*)file->f_path.dentry->d_name.name,
2522 				      &p);
2523 	put_task_struct(task);
2524 	if (length > 0)
2525 		length = simple_read_from_buffer(buf, count, ppos, p, length);
2526 	kfree(p);
2527 	return length;
2528 }
2529 
2530 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2531 				   size_t count, loff_t *ppos)
2532 {
2533 	struct inode * inode = file_inode(file);
2534 	struct task_struct *task;
2535 	void *page;
2536 	int rv;
2537 
2538 	rcu_read_lock();
2539 	task = pid_task(proc_pid(inode), PIDTYPE_PID);
2540 	if (!task) {
2541 		rcu_read_unlock();
2542 		return -ESRCH;
2543 	}
2544 	/* A task may only write its own attributes. */
2545 	if (current != task) {
2546 		rcu_read_unlock();
2547 		return -EACCES;
2548 	}
2549 	rcu_read_unlock();
2550 
2551 	if (count > PAGE_SIZE)
2552 		count = PAGE_SIZE;
2553 
2554 	/* No partial writes. */
2555 	if (*ppos != 0)
2556 		return -EINVAL;
2557 
2558 	page = memdup_user(buf, count);
2559 	if (IS_ERR(page)) {
2560 		rv = PTR_ERR(page);
2561 		goto out;
2562 	}
2563 
2564 	/* Guard against adverse ptrace interaction */
2565 	rv = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
2566 	if (rv < 0)
2567 		goto out_free;
2568 
2569 	rv = security_setprocattr(file->f_path.dentry->d_name.name, page, count);
2570 	mutex_unlock(&current->signal->cred_guard_mutex);
2571 out_free:
2572 	kfree(page);
2573 out:
2574 	return rv;
2575 }
2576 
2577 static const struct file_operations proc_pid_attr_operations = {
2578 	.read		= proc_pid_attr_read,
2579 	.write		= proc_pid_attr_write,
2580 	.llseek		= generic_file_llseek,
2581 };
2582 
2583 static const struct pid_entry attr_dir_stuff[] = {
2584 	REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2585 	REG("prev",       S_IRUGO,	   proc_pid_attr_operations),
2586 	REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2587 	REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2588 	REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2589 	REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2590 };
2591 
2592 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2593 {
2594 	return proc_pident_readdir(file, ctx,
2595 				   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2596 }
2597 
2598 static const struct file_operations proc_attr_dir_operations = {
2599 	.read		= generic_read_dir,
2600 	.iterate_shared	= proc_attr_dir_readdir,
2601 	.llseek		= generic_file_llseek,
2602 };
2603 
2604 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2605 				struct dentry *dentry, unsigned int flags)
2606 {
2607 	return proc_pident_lookup(dir, dentry,
2608 				  attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2609 }
2610 
2611 static const struct inode_operations proc_attr_dir_inode_operations = {
2612 	.lookup		= proc_attr_dir_lookup,
2613 	.getattr	= pid_getattr,
2614 	.setattr	= proc_setattr,
2615 };
2616 
2617 #endif
2618 
2619 #ifdef CONFIG_ELF_CORE
2620 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2621 					 size_t count, loff_t *ppos)
2622 {
2623 	struct task_struct *task = get_proc_task(file_inode(file));
2624 	struct mm_struct *mm;
2625 	char buffer[PROC_NUMBUF];
2626 	size_t len;
2627 	int ret;
2628 
2629 	if (!task)
2630 		return -ESRCH;
2631 
2632 	ret = 0;
2633 	mm = get_task_mm(task);
2634 	if (mm) {
2635 		len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2636 			       ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2637 				MMF_DUMP_FILTER_SHIFT));
2638 		mmput(mm);
2639 		ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2640 	}
2641 
2642 	put_task_struct(task);
2643 
2644 	return ret;
2645 }
2646 
2647 static ssize_t proc_coredump_filter_write(struct file *file,
2648 					  const char __user *buf,
2649 					  size_t count,
2650 					  loff_t *ppos)
2651 {
2652 	struct task_struct *task;
2653 	struct mm_struct *mm;
2654 	unsigned int val;
2655 	int ret;
2656 	int i;
2657 	unsigned long mask;
2658 
2659 	ret = kstrtouint_from_user(buf, count, 0, &val);
2660 	if (ret < 0)
2661 		return ret;
2662 
2663 	ret = -ESRCH;
2664 	task = get_proc_task(file_inode(file));
2665 	if (!task)
2666 		goto out_no_task;
2667 
2668 	mm = get_task_mm(task);
2669 	if (!mm)
2670 		goto out_no_mm;
2671 	ret = 0;
2672 
2673 	for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2674 		if (val & mask)
2675 			set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2676 		else
2677 			clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2678 	}
2679 
2680 	mmput(mm);
2681  out_no_mm:
2682 	put_task_struct(task);
2683  out_no_task:
2684 	if (ret < 0)
2685 		return ret;
2686 	return count;
2687 }
2688 
2689 static const struct file_operations proc_coredump_filter_operations = {
2690 	.read		= proc_coredump_filter_read,
2691 	.write		= proc_coredump_filter_write,
2692 	.llseek		= generic_file_llseek,
2693 };
2694 #endif
2695 
2696 #ifdef CONFIG_TASK_IO_ACCOUNTING
2697 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2698 {
2699 	struct task_io_accounting acct = task->ioac;
2700 	unsigned long flags;
2701 	int result;
2702 
2703 	result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2704 	if (result)
2705 		return result;
2706 
2707 	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2708 		result = -EACCES;
2709 		goto out_unlock;
2710 	}
2711 
2712 	if (whole && lock_task_sighand(task, &flags)) {
2713 		struct task_struct *t = task;
2714 
2715 		task_io_accounting_add(&acct, &task->signal->ioac);
2716 		while_each_thread(task, t)
2717 			task_io_accounting_add(&acct, &t->ioac);
2718 
2719 		unlock_task_sighand(task, &flags);
2720 	}
2721 	seq_printf(m,
2722 		   "rchar: %llu\n"
2723 		   "wchar: %llu\n"
2724 		   "syscr: %llu\n"
2725 		   "syscw: %llu\n"
2726 		   "read_bytes: %llu\n"
2727 		   "write_bytes: %llu\n"
2728 		   "cancelled_write_bytes: %llu\n",
2729 		   (unsigned long long)acct.rchar,
2730 		   (unsigned long long)acct.wchar,
2731 		   (unsigned long long)acct.syscr,
2732 		   (unsigned long long)acct.syscw,
2733 		   (unsigned long long)acct.read_bytes,
2734 		   (unsigned long long)acct.write_bytes,
2735 		   (unsigned long long)acct.cancelled_write_bytes);
2736 	result = 0;
2737 
2738 out_unlock:
2739 	mutex_unlock(&task->signal->cred_guard_mutex);
2740 	return result;
2741 }
2742 
2743 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2744 				  struct pid *pid, struct task_struct *task)
2745 {
2746 	return do_io_accounting(task, m, 0);
2747 }
2748 
2749 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2750 				   struct pid *pid, struct task_struct *task)
2751 {
2752 	return do_io_accounting(task, m, 1);
2753 }
2754 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2755 
2756 #ifdef CONFIG_USER_NS
2757 static int proc_id_map_open(struct inode *inode, struct file *file,
2758 	const struct seq_operations *seq_ops)
2759 {
2760 	struct user_namespace *ns = NULL;
2761 	struct task_struct *task;
2762 	struct seq_file *seq;
2763 	int ret = -EINVAL;
2764 
2765 	task = get_proc_task(inode);
2766 	if (task) {
2767 		rcu_read_lock();
2768 		ns = get_user_ns(task_cred_xxx(task, user_ns));
2769 		rcu_read_unlock();
2770 		put_task_struct(task);
2771 	}
2772 	if (!ns)
2773 		goto err;
2774 
2775 	ret = seq_open(file, seq_ops);
2776 	if (ret)
2777 		goto err_put_ns;
2778 
2779 	seq = file->private_data;
2780 	seq->private = ns;
2781 
2782 	return 0;
2783 err_put_ns:
2784 	put_user_ns(ns);
2785 err:
2786 	return ret;
2787 }
2788 
2789 static int proc_id_map_release(struct inode *inode, struct file *file)
2790 {
2791 	struct seq_file *seq = file->private_data;
2792 	struct user_namespace *ns = seq->private;
2793 	put_user_ns(ns);
2794 	return seq_release(inode, file);
2795 }
2796 
2797 static int proc_uid_map_open(struct inode *inode, struct file *file)
2798 {
2799 	return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2800 }
2801 
2802 static int proc_gid_map_open(struct inode *inode, struct file *file)
2803 {
2804 	return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2805 }
2806 
2807 static int proc_projid_map_open(struct inode *inode, struct file *file)
2808 {
2809 	return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2810 }
2811 
2812 static const struct file_operations proc_uid_map_operations = {
2813 	.open		= proc_uid_map_open,
2814 	.write		= proc_uid_map_write,
2815 	.read		= seq_read,
2816 	.llseek		= seq_lseek,
2817 	.release	= proc_id_map_release,
2818 };
2819 
2820 static const struct file_operations proc_gid_map_operations = {
2821 	.open		= proc_gid_map_open,
2822 	.write		= proc_gid_map_write,
2823 	.read		= seq_read,
2824 	.llseek		= seq_lseek,
2825 	.release	= proc_id_map_release,
2826 };
2827 
2828 static const struct file_operations proc_projid_map_operations = {
2829 	.open		= proc_projid_map_open,
2830 	.write		= proc_projid_map_write,
2831 	.read		= seq_read,
2832 	.llseek		= seq_lseek,
2833 	.release	= proc_id_map_release,
2834 };
2835 
2836 static int proc_setgroups_open(struct inode *inode, struct file *file)
2837 {
2838 	struct user_namespace *ns = NULL;
2839 	struct task_struct *task;
2840 	int ret;
2841 
2842 	ret = -ESRCH;
2843 	task = get_proc_task(inode);
2844 	if (task) {
2845 		rcu_read_lock();
2846 		ns = get_user_ns(task_cred_xxx(task, user_ns));
2847 		rcu_read_unlock();
2848 		put_task_struct(task);
2849 	}
2850 	if (!ns)
2851 		goto err;
2852 
2853 	if (file->f_mode & FMODE_WRITE) {
2854 		ret = -EACCES;
2855 		if (!ns_capable(ns, CAP_SYS_ADMIN))
2856 			goto err_put_ns;
2857 	}
2858 
2859 	ret = single_open(file, &proc_setgroups_show, ns);
2860 	if (ret)
2861 		goto err_put_ns;
2862 
2863 	return 0;
2864 err_put_ns:
2865 	put_user_ns(ns);
2866 err:
2867 	return ret;
2868 }
2869 
2870 static int proc_setgroups_release(struct inode *inode, struct file *file)
2871 {
2872 	struct seq_file *seq = file->private_data;
2873 	struct user_namespace *ns = seq->private;
2874 	int ret = single_release(inode, file);
2875 	put_user_ns(ns);
2876 	return ret;
2877 }
2878 
2879 static const struct file_operations proc_setgroups_operations = {
2880 	.open		= proc_setgroups_open,
2881 	.write		= proc_setgroups_write,
2882 	.read		= seq_read,
2883 	.llseek		= seq_lseek,
2884 	.release	= proc_setgroups_release,
2885 };
2886 #endif /* CONFIG_USER_NS */
2887 
2888 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2889 				struct pid *pid, struct task_struct *task)
2890 {
2891 	int err = lock_trace(task);
2892 	if (!err) {
2893 		seq_printf(m, "%08x\n", task->personality);
2894 		unlock_trace(task);
2895 	}
2896 	return err;
2897 }
2898 
2899 #ifdef CONFIG_LIVEPATCH
2900 static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns,
2901 				struct pid *pid, struct task_struct *task)
2902 {
2903 	seq_printf(m, "%d\n", task->patch_state);
2904 	return 0;
2905 }
2906 #endif /* CONFIG_LIVEPATCH */
2907 
2908 /*
2909  * Thread groups
2910  */
2911 static const struct file_operations proc_task_operations;
2912 static const struct inode_operations proc_task_inode_operations;
2913 
2914 static const struct pid_entry tgid_base_stuff[] = {
2915 	DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2916 	DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2917 	DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2918 	DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2919 	DIR("ns",	  S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2920 #ifdef CONFIG_NET
2921 	DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2922 #endif
2923 	REG("environ",    S_IRUSR, proc_environ_operations),
2924 	REG("auxv",       S_IRUSR, proc_auxv_operations),
2925 	ONE("status",     S_IRUGO, proc_pid_status),
2926 	ONE("personality", S_IRUSR, proc_pid_personality),
2927 	ONE("limits",	  S_IRUGO, proc_pid_limits),
2928 #ifdef CONFIG_SCHED_DEBUG
2929 	REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2930 #endif
2931 #ifdef CONFIG_SCHED_AUTOGROUP
2932 	REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2933 #endif
2934 	REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2935 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2936 	ONE("syscall",    S_IRUSR, proc_pid_syscall),
2937 #endif
2938 	REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
2939 	ONE("stat",       S_IRUGO, proc_tgid_stat),
2940 	ONE("statm",      S_IRUGO, proc_pid_statm),
2941 	REG("maps",       S_IRUGO, proc_pid_maps_operations),
2942 #ifdef CONFIG_NUMA
2943 	REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2944 #endif
2945 	REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2946 	LNK("cwd",        proc_cwd_link),
2947 	LNK("root",       proc_root_link),
2948 	LNK("exe",        proc_exe_link),
2949 	REG("mounts",     S_IRUGO, proc_mounts_operations),
2950 	REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2951 	REG("mountstats", S_IRUSR, proc_mountstats_operations),
2952 #ifdef CONFIG_PROC_PAGE_MONITOR
2953 	REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2954 	REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2955 	REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
2956 	REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2957 #endif
2958 #ifdef CONFIG_SECURITY
2959 	DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2960 #endif
2961 #ifdef CONFIG_KALLSYMS
2962 	ONE("wchan",      S_IRUGO, proc_pid_wchan),
2963 #endif
2964 #ifdef CONFIG_STACKTRACE
2965 	ONE("stack",      S_IRUSR, proc_pid_stack),
2966 #endif
2967 #ifdef CONFIG_SCHED_INFO
2968 	ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
2969 #endif
2970 #ifdef CONFIG_LATENCYTOP
2971 	REG("latency",  S_IRUGO, proc_lstats_operations),
2972 #endif
2973 #ifdef CONFIG_PROC_PID_CPUSET
2974 	ONE("cpuset",     S_IRUGO, proc_cpuset_show),
2975 #endif
2976 #ifdef CONFIG_CGROUPS
2977 	ONE("cgroup",  S_IRUGO, proc_cgroup_show),
2978 #endif
2979 	ONE("oom_score",  S_IRUGO, proc_oom_score),
2980 	REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
2981 	REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2982 #ifdef CONFIG_AUDITSYSCALL
2983 	REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2984 	REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2985 #endif
2986 #ifdef CONFIG_FAULT_INJECTION
2987 	REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2988 	REG("fail-nth", 0644, proc_fail_nth_operations),
2989 #endif
2990 #ifdef CONFIG_ELF_CORE
2991 	REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2992 #endif
2993 #ifdef CONFIG_TASK_IO_ACCOUNTING
2994 	ONE("io",	S_IRUSR, proc_tgid_io_accounting),
2995 #endif
2996 #ifdef CONFIG_USER_NS
2997 	REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
2998 	REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
2999 	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3000 	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3001 #endif
3002 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
3003 	REG("timers",	  S_IRUGO, proc_timers_operations),
3004 #endif
3005 	REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
3006 #ifdef CONFIG_LIVEPATCH
3007 	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3008 #endif
3009 };
3010 
3011 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
3012 {
3013 	return proc_pident_readdir(file, ctx,
3014 				   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3015 }
3016 
3017 static const struct file_operations proc_tgid_base_operations = {
3018 	.read		= generic_read_dir,
3019 	.iterate_shared	= proc_tgid_base_readdir,
3020 	.llseek		= generic_file_llseek,
3021 };
3022 
3023 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3024 {
3025 	return proc_pident_lookup(dir, dentry,
3026 				  tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3027 }
3028 
3029 static const struct inode_operations proc_tgid_base_inode_operations = {
3030 	.lookup		= proc_tgid_base_lookup,
3031 	.getattr	= pid_getattr,
3032 	.setattr	= proc_setattr,
3033 	.permission	= proc_pid_permission,
3034 };
3035 
3036 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
3037 {
3038 	struct dentry *dentry, *leader, *dir;
3039 	char buf[10 + 1];
3040 	struct qstr name;
3041 
3042 	name.name = buf;
3043 	name.len = snprintf(buf, sizeof(buf), "%u", pid);
3044 	/* no ->d_hash() rejects on procfs */
3045 	dentry = d_hash_and_lookup(mnt->mnt_root, &name);
3046 	if (dentry) {
3047 		d_invalidate(dentry);
3048 		dput(dentry);
3049 	}
3050 
3051 	if (pid == tgid)
3052 		return;
3053 
3054 	name.name = buf;
3055 	name.len = snprintf(buf, sizeof(buf), "%u", tgid);
3056 	leader = d_hash_and_lookup(mnt->mnt_root, &name);
3057 	if (!leader)
3058 		goto out;
3059 
3060 	name.name = "task";
3061 	name.len = strlen(name.name);
3062 	dir = d_hash_and_lookup(leader, &name);
3063 	if (!dir)
3064 		goto out_put_leader;
3065 
3066 	name.name = buf;
3067 	name.len = snprintf(buf, sizeof(buf), "%u", pid);
3068 	dentry = d_hash_and_lookup(dir, &name);
3069 	if (dentry) {
3070 		d_invalidate(dentry);
3071 		dput(dentry);
3072 	}
3073 
3074 	dput(dir);
3075 out_put_leader:
3076 	dput(leader);
3077 out:
3078 	return;
3079 }
3080 
3081 /**
3082  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
3083  * @task: task that should be flushed.
3084  *
3085  * When flushing dentries from proc, one needs to flush them from global
3086  * proc (proc_mnt) and from all the namespaces' procs this task was seen
3087  * in. This call is supposed to do all of this job.
3088  *
3089  * Looks in the dcache for
3090  * /proc/@pid
3091  * /proc/@tgid/task/@pid
3092  * if either directory is present flushes it and all of it'ts children
3093  * from the dcache.
3094  *
3095  * It is safe and reasonable to cache /proc entries for a task until
3096  * that task exits.  After that they just clog up the dcache with
3097  * useless entries, possibly causing useful dcache entries to be
3098  * flushed instead.  This routine is proved to flush those useless
3099  * dcache entries at process exit time.
3100  *
3101  * NOTE: This routine is just an optimization so it does not guarantee
3102  *       that no dcache entries will exist at process exit time it
3103  *       just makes it very unlikely that any will persist.
3104  */
3105 
3106 void proc_flush_task(struct task_struct *task)
3107 {
3108 	int i;
3109 	struct pid *pid, *tgid;
3110 	struct upid *upid;
3111 
3112 	pid = task_pid(task);
3113 	tgid = task_tgid(task);
3114 
3115 	for (i = 0; i <= pid->level; i++) {
3116 		upid = &pid->numbers[i];
3117 		proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3118 					tgid->numbers[i].nr);
3119 	}
3120 }
3121 
3122 static struct dentry *proc_pid_instantiate(struct dentry * dentry,
3123 				   struct task_struct *task, const void *ptr)
3124 {
3125 	struct inode *inode;
3126 
3127 	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3128 	if (!inode)
3129 		return ERR_PTR(-ENOENT);
3130 
3131 	inode->i_op = &proc_tgid_base_inode_operations;
3132 	inode->i_fop = &proc_tgid_base_operations;
3133 	inode->i_flags|=S_IMMUTABLE;
3134 
3135 	set_nlink(inode, nlink_tgid);
3136 	pid_update_inode(task, inode);
3137 
3138 	d_set_d_op(dentry, &pid_dentry_operations);
3139 	return d_splice_alias(inode, dentry);
3140 }
3141 
3142 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3143 {
3144 	struct task_struct *task;
3145 	unsigned tgid;
3146 	struct pid_namespace *ns;
3147 	struct dentry *result = ERR_PTR(-ENOENT);
3148 
3149 	tgid = name_to_int(&dentry->d_name);
3150 	if (tgid == ~0U)
3151 		goto out;
3152 
3153 	ns = dentry->d_sb->s_fs_info;
3154 	rcu_read_lock();
3155 	task = find_task_by_pid_ns(tgid, ns);
3156 	if (task)
3157 		get_task_struct(task);
3158 	rcu_read_unlock();
3159 	if (!task)
3160 		goto out;
3161 
3162 	result = proc_pid_instantiate(dentry, task, NULL);
3163 	put_task_struct(task);
3164 out:
3165 	return result;
3166 }
3167 
3168 /*
3169  * Find the first task with tgid >= tgid
3170  *
3171  */
3172 struct tgid_iter {
3173 	unsigned int tgid;
3174 	struct task_struct *task;
3175 };
3176 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3177 {
3178 	struct pid *pid;
3179 
3180 	if (iter.task)
3181 		put_task_struct(iter.task);
3182 	rcu_read_lock();
3183 retry:
3184 	iter.task = NULL;
3185 	pid = find_ge_pid(iter.tgid, ns);
3186 	if (pid) {
3187 		iter.tgid = pid_nr_ns(pid, ns);
3188 		iter.task = pid_task(pid, PIDTYPE_PID);
3189 		/* What we to know is if the pid we have find is the
3190 		 * pid of a thread_group_leader.  Testing for task
3191 		 * being a thread_group_leader is the obvious thing
3192 		 * todo but there is a window when it fails, due to
3193 		 * the pid transfer logic in de_thread.
3194 		 *
3195 		 * So we perform the straight forward test of seeing
3196 		 * if the pid we have found is the pid of a thread
3197 		 * group leader, and don't worry if the task we have
3198 		 * found doesn't happen to be a thread group leader.
3199 		 * As we don't care in the case of readdir.
3200 		 */
3201 		if (!iter.task || !has_group_leader_pid(iter.task)) {
3202 			iter.tgid += 1;
3203 			goto retry;
3204 		}
3205 		get_task_struct(iter.task);
3206 	}
3207 	rcu_read_unlock();
3208 	return iter;
3209 }
3210 
3211 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3212 
3213 /* for the /proc/ directory itself, after non-process stuff has been done */
3214 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3215 {
3216 	struct tgid_iter iter;
3217 	struct pid_namespace *ns = proc_pid_ns(file_inode(file));
3218 	loff_t pos = ctx->pos;
3219 
3220 	if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3221 		return 0;
3222 
3223 	if (pos == TGID_OFFSET - 2) {
3224 		struct inode *inode = d_inode(ns->proc_self);
3225 		if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3226 			return 0;
3227 		ctx->pos = pos = pos + 1;
3228 	}
3229 	if (pos == TGID_OFFSET - 1) {
3230 		struct inode *inode = d_inode(ns->proc_thread_self);
3231 		if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3232 			return 0;
3233 		ctx->pos = pos = pos + 1;
3234 	}
3235 	iter.tgid = pos - TGID_OFFSET;
3236 	iter.task = NULL;
3237 	for (iter = next_tgid(ns, iter);
3238 	     iter.task;
3239 	     iter.tgid += 1, iter = next_tgid(ns, iter)) {
3240 		char name[10 + 1];
3241 		unsigned int len;
3242 
3243 		cond_resched();
3244 		if (!has_pid_permissions(ns, iter.task, HIDEPID_INVISIBLE))
3245 			continue;
3246 
3247 		len = snprintf(name, sizeof(name), "%u", iter.tgid);
3248 		ctx->pos = iter.tgid + TGID_OFFSET;
3249 		if (!proc_fill_cache(file, ctx, name, len,
3250 				     proc_pid_instantiate, iter.task, NULL)) {
3251 			put_task_struct(iter.task);
3252 			return 0;
3253 		}
3254 	}
3255 	ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3256 	return 0;
3257 }
3258 
3259 /*
3260  * proc_tid_comm_permission is a special permission function exclusively
3261  * used for the node /proc/<pid>/task/<tid>/comm.
3262  * It bypasses generic permission checks in the case where a task of the same
3263  * task group attempts to access the node.
3264  * The rationale behind this is that glibc and bionic access this node for
3265  * cross thread naming (pthread_set/getname_np(!self)). However, if
3266  * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3267  * which locks out the cross thread naming implementation.
3268  * This function makes sure that the node is always accessible for members of
3269  * same thread group.
3270  */
3271 static int proc_tid_comm_permission(struct inode *inode, int mask)
3272 {
3273 	bool is_same_tgroup;
3274 	struct task_struct *task;
3275 
3276 	task = get_proc_task(inode);
3277 	if (!task)
3278 		return -ESRCH;
3279 	is_same_tgroup = same_thread_group(current, task);
3280 	put_task_struct(task);
3281 
3282 	if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3283 		/* This file (/proc/<pid>/task/<tid>/comm) can always be
3284 		 * read or written by the members of the corresponding
3285 		 * thread group.
3286 		 */
3287 		return 0;
3288 	}
3289 
3290 	return generic_permission(inode, mask);
3291 }
3292 
3293 static const struct inode_operations proc_tid_comm_inode_operations = {
3294 		.permission = proc_tid_comm_permission,
3295 };
3296 
3297 /*
3298  * Tasks
3299  */
3300 static const struct pid_entry tid_base_stuff[] = {
3301 	DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3302 	DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3303 	DIR("ns",	 S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3304 #ifdef CONFIG_NET
3305 	DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3306 #endif
3307 	REG("environ",   S_IRUSR, proc_environ_operations),
3308 	REG("auxv",      S_IRUSR, proc_auxv_operations),
3309 	ONE("status",    S_IRUGO, proc_pid_status),
3310 	ONE("personality", S_IRUSR, proc_pid_personality),
3311 	ONE("limits",	 S_IRUGO, proc_pid_limits),
3312 #ifdef CONFIG_SCHED_DEBUG
3313 	REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3314 #endif
3315 	NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3316 			 &proc_tid_comm_inode_operations,
3317 			 &proc_pid_set_comm_operations, {}),
3318 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3319 	ONE("syscall",   S_IRUSR, proc_pid_syscall),
3320 #endif
3321 	REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3322 	ONE("stat",      S_IRUGO, proc_tid_stat),
3323 	ONE("statm",     S_IRUGO, proc_pid_statm),
3324 	REG("maps",      S_IRUGO, proc_pid_maps_operations),
3325 #ifdef CONFIG_PROC_CHILDREN
3326 	REG("children",  S_IRUGO, proc_tid_children_operations),
3327 #endif
3328 #ifdef CONFIG_NUMA
3329 	REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations),
3330 #endif
3331 	REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3332 	LNK("cwd",       proc_cwd_link),
3333 	LNK("root",      proc_root_link),
3334 	LNK("exe",       proc_exe_link),
3335 	REG("mounts",    S_IRUGO, proc_mounts_operations),
3336 	REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3337 #ifdef CONFIG_PROC_PAGE_MONITOR
3338 	REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3339 	REG("smaps",     S_IRUGO, proc_pid_smaps_operations),
3340 	REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3341 	REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3342 #endif
3343 #ifdef CONFIG_SECURITY
3344 	DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3345 #endif
3346 #ifdef CONFIG_KALLSYMS
3347 	ONE("wchan",     S_IRUGO, proc_pid_wchan),
3348 #endif
3349 #ifdef CONFIG_STACKTRACE
3350 	ONE("stack",      S_IRUSR, proc_pid_stack),
3351 #endif
3352 #ifdef CONFIG_SCHED_INFO
3353 	ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3354 #endif
3355 #ifdef CONFIG_LATENCYTOP
3356 	REG("latency",  S_IRUGO, proc_lstats_operations),
3357 #endif
3358 #ifdef CONFIG_PROC_PID_CPUSET
3359 	ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3360 #endif
3361 #ifdef CONFIG_CGROUPS
3362 	ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3363 #endif
3364 	ONE("oom_score", S_IRUGO, proc_oom_score),
3365 	REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3366 	REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3367 #ifdef CONFIG_AUDITSYSCALL
3368 	REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3369 	REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3370 #endif
3371 #ifdef CONFIG_FAULT_INJECTION
3372 	REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3373 	REG("fail-nth", 0644, proc_fail_nth_operations),
3374 #endif
3375 #ifdef CONFIG_TASK_IO_ACCOUNTING
3376 	ONE("io",	S_IRUSR, proc_tid_io_accounting),
3377 #endif
3378 #ifdef CONFIG_USER_NS
3379 	REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3380 	REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3381 	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3382 	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3383 #endif
3384 #ifdef CONFIG_LIVEPATCH
3385 	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3386 #endif
3387 };
3388 
3389 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3390 {
3391 	return proc_pident_readdir(file, ctx,
3392 				   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3393 }
3394 
3395 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3396 {
3397 	return proc_pident_lookup(dir, dentry,
3398 				  tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3399 }
3400 
3401 static const struct file_operations proc_tid_base_operations = {
3402 	.read		= generic_read_dir,
3403 	.iterate_shared	= proc_tid_base_readdir,
3404 	.llseek		= generic_file_llseek,
3405 };
3406 
3407 static const struct inode_operations proc_tid_base_inode_operations = {
3408 	.lookup		= proc_tid_base_lookup,
3409 	.getattr	= pid_getattr,
3410 	.setattr	= proc_setattr,
3411 };
3412 
3413 static struct dentry *proc_task_instantiate(struct dentry *dentry,
3414 	struct task_struct *task, const void *ptr)
3415 {
3416 	struct inode *inode;
3417 	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3418 	if (!inode)
3419 		return ERR_PTR(-ENOENT);
3420 
3421 	inode->i_op = &proc_tid_base_inode_operations;
3422 	inode->i_fop = &proc_tid_base_operations;
3423 	inode->i_flags |= S_IMMUTABLE;
3424 
3425 	set_nlink(inode, nlink_tid);
3426 	pid_update_inode(task, inode);
3427 
3428 	d_set_d_op(dentry, &pid_dentry_operations);
3429 	return d_splice_alias(inode, dentry);
3430 }
3431 
3432 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3433 {
3434 	struct task_struct *task;
3435 	struct task_struct *leader = get_proc_task(dir);
3436 	unsigned tid;
3437 	struct pid_namespace *ns;
3438 	struct dentry *result = ERR_PTR(-ENOENT);
3439 
3440 	if (!leader)
3441 		goto out_no_task;
3442 
3443 	tid = name_to_int(&dentry->d_name);
3444 	if (tid == ~0U)
3445 		goto out;
3446 
3447 	ns = dentry->d_sb->s_fs_info;
3448 	rcu_read_lock();
3449 	task = find_task_by_pid_ns(tid, ns);
3450 	if (task)
3451 		get_task_struct(task);
3452 	rcu_read_unlock();
3453 	if (!task)
3454 		goto out;
3455 	if (!same_thread_group(leader, task))
3456 		goto out_drop_task;
3457 
3458 	result = proc_task_instantiate(dentry, task, NULL);
3459 out_drop_task:
3460 	put_task_struct(task);
3461 out:
3462 	put_task_struct(leader);
3463 out_no_task:
3464 	return result;
3465 }
3466 
3467 /*
3468  * Find the first tid of a thread group to return to user space.
3469  *
3470  * Usually this is just the thread group leader, but if the users
3471  * buffer was too small or there was a seek into the middle of the
3472  * directory we have more work todo.
3473  *
3474  * In the case of a short read we start with find_task_by_pid.
3475  *
3476  * In the case of a seek we start with the leader and walk nr
3477  * threads past it.
3478  */
3479 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3480 					struct pid_namespace *ns)
3481 {
3482 	struct task_struct *pos, *task;
3483 	unsigned long nr = f_pos;
3484 
3485 	if (nr != f_pos)	/* 32bit overflow? */
3486 		return NULL;
3487 
3488 	rcu_read_lock();
3489 	task = pid_task(pid, PIDTYPE_PID);
3490 	if (!task)
3491 		goto fail;
3492 
3493 	/* Attempt to start with the tid of a thread */
3494 	if (tid && nr) {
3495 		pos = find_task_by_pid_ns(tid, ns);
3496 		if (pos && same_thread_group(pos, task))
3497 			goto found;
3498 	}
3499 
3500 	/* If nr exceeds the number of threads there is nothing todo */
3501 	if (nr >= get_nr_threads(task))
3502 		goto fail;
3503 
3504 	/* If we haven't found our starting place yet start
3505 	 * with the leader and walk nr threads forward.
3506 	 */
3507 	pos = task = task->group_leader;
3508 	do {
3509 		if (!nr--)
3510 			goto found;
3511 	} while_each_thread(task, pos);
3512 fail:
3513 	pos = NULL;
3514 	goto out;
3515 found:
3516 	get_task_struct(pos);
3517 out:
3518 	rcu_read_unlock();
3519 	return pos;
3520 }
3521 
3522 /*
3523  * Find the next thread in the thread list.
3524  * Return NULL if there is an error or no next thread.
3525  *
3526  * The reference to the input task_struct is released.
3527  */
3528 static struct task_struct *next_tid(struct task_struct *start)
3529 {
3530 	struct task_struct *pos = NULL;
3531 	rcu_read_lock();
3532 	if (pid_alive(start)) {
3533 		pos = next_thread(start);
3534 		if (thread_group_leader(pos))
3535 			pos = NULL;
3536 		else
3537 			get_task_struct(pos);
3538 	}
3539 	rcu_read_unlock();
3540 	put_task_struct(start);
3541 	return pos;
3542 }
3543 
3544 /* for the /proc/TGID/task/ directories */
3545 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3546 {
3547 	struct inode *inode = file_inode(file);
3548 	struct task_struct *task;
3549 	struct pid_namespace *ns;
3550 	int tid;
3551 
3552 	if (proc_inode_is_dead(inode))
3553 		return -ENOENT;
3554 
3555 	if (!dir_emit_dots(file, ctx))
3556 		return 0;
3557 
3558 	/* f_version caches the tgid value that the last readdir call couldn't
3559 	 * return. lseek aka telldir automagically resets f_version to 0.
3560 	 */
3561 	ns = proc_pid_ns(inode);
3562 	tid = (int)file->f_version;
3563 	file->f_version = 0;
3564 	for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3565 	     task;
3566 	     task = next_tid(task), ctx->pos++) {
3567 		char name[10 + 1];
3568 		unsigned int len;
3569 		tid = task_pid_nr_ns(task, ns);
3570 		len = snprintf(name, sizeof(name), "%u", tid);
3571 		if (!proc_fill_cache(file, ctx, name, len,
3572 				proc_task_instantiate, task, NULL)) {
3573 			/* returning this tgid failed, save it as the first
3574 			 * pid for the next readir call */
3575 			file->f_version = (u64)tid;
3576 			put_task_struct(task);
3577 			break;
3578 		}
3579 	}
3580 
3581 	return 0;
3582 }
3583 
3584 static int proc_task_getattr(const struct path *path, struct kstat *stat,
3585 			     u32 request_mask, unsigned int query_flags)
3586 {
3587 	struct inode *inode = d_inode(path->dentry);
3588 	struct task_struct *p = get_proc_task(inode);
3589 	generic_fillattr(inode, stat);
3590 
3591 	if (p) {
3592 		stat->nlink += get_nr_threads(p);
3593 		put_task_struct(p);
3594 	}
3595 
3596 	return 0;
3597 }
3598 
3599 static const struct inode_operations proc_task_inode_operations = {
3600 	.lookup		= proc_task_lookup,
3601 	.getattr	= proc_task_getattr,
3602 	.setattr	= proc_setattr,
3603 	.permission	= proc_pid_permission,
3604 };
3605 
3606 static const struct file_operations proc_task_operations = {
3607 	.read		= generic_read_dir,
3608 	.iterate_shared	= proc_task_readdir,
3609 	.llseek		= generic_file_llseek,
3610 };
3611 
3612 void __init set_proc_pid_nlink(void)
3613 {
3614 	nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3615 	nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3616 }
3617