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
 113static u8 nlink_tid __ro_after_init;
 114static u8 nlink_tgid __ro_after_init;
 115
 116struct 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 */
 151static 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
 166static 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
 179static 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
 196static 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
 208static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 209				     size_t _count, loff_t *pos)
 
 
 
 
 
 210{
 211	struct task_struct *tsk;
 212	struct mm_struct *mm;
 213	char *page;
 214	unsigned long count = _count;
 215	unsigned long arg_start, arg_end, env_start, env_end;
 216	unsigned long len1, len2, len;
 217	unsigned long p;
 218	char c;
 219	ssize_t rv;
 220
 221	BUG_ON(*pos < 0);
 222
 223	tsk = get_proc_task(file_inode(file));
 224	if (!tsk)
 225		return -ESRCH;
 226	mm = get_task_mm(tsk);
 227	put_task_struct(tsk);
 228	if (!mm)
 229		return 0;
 230	/* Check if process spawned far enough to have cmdline. */
 231	if (!mm->env_end) {
 232		rv = 0;
 233		goto out_mmput;
 234	}
 235
 236	page = (char *)__get_free_page(GFP_KERNEL);
 237	if (!page) {
 238		rv = -ENOMEM;
 239		goto out_mmput;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 240	}
 
 
 
 241
 242	down_read(&mm->mmap_sem);
 
 
 
 
 
 
 
 
 
 
 
 243	arg_start = mm->arg_start;
 244	arg_end = mm->arg_end;
 245	env_start = mm->env_start;
 246	env_end = mm->env_end;
 247	up_read(&mm->mmap_sem);
 248
 249	BUG_ON(arg_start > arg_end);
 250	BUG_ON(env_start > env_end);
 251
 252	len1 = arg_end - arg_start;
 253	len2 = env_end - env_start;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 254
 255	/* Empty ARGV. */
 256	if (len1 == 0) {
 257		rv = 0;
 258		goto out_free_page;
 259	}
 260	/*
 261	 * Inherently racy -- command line shares address space
 262	 * with code and data.
 263	 */
 264	rv = access_remote_vm(mm, arg_end - 1, &c, 1, FOLL_ANON);
 265	if (rv <= 0)
 266		goto out_free_page;
 267
 268	rv = 0;
 269
 270	if (c == '\0') {
 271		/* Command line (set of strings) occupies whole ARGV. */
 272		if (len1 <= *pos)
 273			goto out_free_page;
 274
 275		p = arg_start + *pos;
 276		len = len1 - *pos;
 277		while (count > 0 && len > 0) {
 278			unsigned int _count;
 279			int nr_read;
 280
 281			_count = min3(count, len, PAGE_SIZE);
 282			nr_read = access_remote_vm(mm, p, page, _count, FOLL_ANON);
 283			if (nr_read < 0)
 284				rv = nr_read;
 285			if (nr_read <= 0)
 286				goto out_free_page;
 287
 288			if (copy_to_user(buf, page, nr_read)) {
 289				rv = -EFAULT;
 290				goto out_free_page;
 291			}
 292
 293			p	+= nr_read;
 294			len	-= nr_read;
 295			buf	+= nr_read;
 296			count	-= nr_read;
 297			rv	+= nr_read;
 298		}
 299	} else {
 300		/*
 301		 * Command line (1 string) occupies ARGV and
 302		 * extends into ENVP.
 303		 */
 304		struct {
 305			unsigned long p;
 306			unsigned long len;
 307		} cmdline[2] = {
 308			{ .p = arg_start, .len = len1 },
 309			{ .p = env_start, .len = len2 },
 310		};
 311		loff_t pos1 = *pos;
 312		unsigned int i;
 313
 314		i = 0;
 315		while (i < 2 && pos1 >= cmdline[i].len) {
 316			pos1 -= cmdline[i].len;
 317			i++;
 318		}
 319		while (i < 2) {
 320			p = cmdline[i].p + pos1;
 321			len = cmdline[i].len - pos1;
 322			while (count > 0 && len > 0) {
 323				unsigned int _count, l;
 324				int nr_read;
 325				bool final;
 326
 327				_count = min3(count, len, PAGE_SIZE);
 328				nr_read = access_remote_vm(mm, p, page, _count, FOLL_ANON);
 329				if (nr_read < 0)
 330					rv = nr_read;
 331				if (nr_read <= 0)
 332					goto out_free_page;
 333
 334				/*
 335				 * Command line can be shorter than whole ARGV
 336				 * even if last "marker" byte says it is not.
 337				 */
 338				final = false;
 339				l = strnlen(page, nr_read);
 340				if (l < nr_read) {
 341					nr_read = l;
 342					final = true;
 343				}
 344
 345				if (copy_to_user(buf, page, nr_read)) {
 346					rv = -EFAULT;
 347					goto out_free_page;
 348				}
 349
 350				p	+= nr_read;
 351				len	-= nr_read;
 352				buf	+= nr_read;
 353				count	-= nr_read;
 354				rv	+= nr_read;
 355
 356				if (final)
 357					goto out_free_page;
 358			}
 
 359
 360			/* Only first chunk can be read partially. */
 361			pos1 = 0;
 362			i++;
 
 
 
 
 
 363		}
 
 
 
 
 364	}
 365
 366out_free_page:
 367	free_page((unsigned long)page);
 368out_mmput:
 
 
 
 
 
 
 
 
 
 
 
 
 
 369	mmput(mm);
 370	if (rv > 0)
 371		*pos += rv;
 372	return rv;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 373}
 374
 375static const struct file_operations proc_pid_cmdline_ops = {
 376	.read	= proc_pid_cmdline_read,
 377	.llseek	= generic_file_llseek,
 378};
 379
 380#ifdef CONFIG_KALLSYMS
 381/*
 382 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 383 * Returns the resolved symbol.  If that fails, simply return the address.
 384 */
 385static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 386			  struct pid *pid, struct task_struct *task)
 387{
 388	unsigned long wchan;
 389	char symname[KSYM_NAME_LEN];
 390
 391	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
 392		goto print0;
 393
 394	wchan = get_wchan(task);
 395	if (wchan && !lookup_symbol_name(wchan, symname)) {
 396		seq_puts(m, symname);
 397		return 0;
 398	}
 399
 400print0:
 401	seq_putc(m, '0');
 402	return 0;
 403}
 404#endif /* CONFIG_KALLSYMS */
 405
 406static int lock_trace(struct task_struct *task)
 407{
 408	int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 409	if (err)
 410		return err;
 411	if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 412		mutex_unlock(&task->signal->cred_guard_mutex);
 413		return -EPERM;
 414	}
 415	return 0;
 416}
 417
 418static void unlock_trace(struct task_struct *task)
 419{
 420	mutex_unlock(&task->signal->cred_guard_mutex);
 421}
 422
 423#ifdef CONFIG_STACKTRACE
 424
 425#define MAX_STACK_TRACE_DEPTH	64
 426
 427static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 428			  struct pid *pid, struct task_struct *task)
 429{
 430	struct stack_trace trace;
 431	unsigned long *entries;
 432	int err;
 433	int i;
 434
 435	entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 436	if (!entries)
 437		return -ENOMEM;
 438
 439	trace.nr_entries	= 0;
 440	trace.max_entries	= MAX_STACK_TRACE_DEPTH;
 441	trace.entries		= entries;
 442	trace.skip		= 0;
 443
 444	err = lock_trace(task);
 445	if (!err) {
 446		save_stack_trace_tsk(task, &trace);
 
 
 
 447
 448		for (i = 0; i < trace.nr_entries; i++) {
 449			seq_printf(m, "[<0>] %pB\n", (void *)entries[i]);
 450		}
 
 451		unlock_trace(task);
 452	}
 453	kfree(entries);
 454
 455	return err;
 456}
 457#endif
 458
 459#ifdef CONFIG_SCHED_INFO
 460/*
 461 * Provides /proc/PID/schedstat
 462 */
 463static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 464			      struct pid *pid, struct task_struct *task)
 465{
 466	if (unlikely(!sched_info_on()))
 467		seq_printf(m, "0 0 0\n");
 468	else
 469		seq_printf(m, "%llu %llu %lu\n",
 470		   (unsigned long long)task->se.sum_exec_runtime,
 471		   (unsigned long long)task->sched_info.run_delay,
 472		   task->sched_info.pcount);
 473
 474	return 0;
 475}
 476#endif
 477
 478#ifdef CONFIG_LATENCYTOP
 479static int lstats_show_proc(struct seq_file *m, void *v)
 480{
 481	int i;
 482	struct inode *inode = m->private;
 483	struct task_struct *task = get_proc_task(inode);
 484
 485	if (!task)
 486		return -ESRCH;
 487	seq_puts(m, "Latency Top version : v0.1\n");
 488	for (i = 0; i < 32; i++) {
 489		struct latency_record *lr = &task->latency_record[i];
 490		if (lr->backtrace[0]) {
 491			int q;
 492			seq_printf(m, "%i %li %li",
 493				   lr->count, lr->time, lr->max);
 494			for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 495				unsigned long bt = lr->backtrace[q];
 
 496				if (!bt)
 497					break;
 498				if (bt == ULONG_MAX)
 499					break;
 500				seq_printf(m, " %ps", (void *)bt);
 501			}
 502			seq_putc(m, '\n');
 503		}
 504
 505	}
 506	put_task_struct(task);
 507	return 0;
 508}
 509
 510static int lstats_open(struct inode *inode, struct file *file)
 511{
 512	return single_open(file, lstats_show_proc, inode);
 513}
 514
 515static ssize_t lstats_write(struct file *file, const char __user *buf,
 516			    size_t count, loff_t *offs)
 517{
 518	struct task_struct *task = get_proc_task(file_inode(file));
 519
 520	if (!task)
 521		return -ESRCH;
 522	clear_all_latency_tracing(task);
 523	put_task_struct(task);
 524
 525	return count;
 526}
 527
 528static const struct file_operations proc_lstats_operations = {
 529	.open		= lstats_open,
 530	.read		= seq_read,
 531	.write		= lstats_write,
 532	.llseek		= seq_lseek,
 533	.release	= single_release,
 534};
 535
 536#endif
 537
 538static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 539			  struct pid *pid, struct task_struct *task)
 540{
 541	unsigned long totalpages = totalram_pages + total_swap_pages;
 542	unsigned long points = 0;
 543
 544	points = oom_badness(task, NULL, NULL, totalpages) *
 545					1000 / totalpages;
 546	seq_printf(m, "%lu\n", points);
 547
 548	return 0;
 549}
 550
 551struct limit_names {
 552	const char *name;
 553	const char *unit;
 554};
 555
 556static const struct limit_names lnames[RLIM_NLIMITS] = {
 557	[RLIMIT_CPU] = {"Max cpu time", "seconds"},
 558	[RLIMIT_FSIZE] = {"Max file size", "bytes"},
 559	[RLIMIT_DATA] = {"Max data size", "bytes"},
 560	[RLIMIT_STACK] = {"Max stack size", "bytes"},
 561	[RLIMIT_CORE] = {"Max core file size", "bytes"},
 562	[RLIMIT_RSS] = {"Max resident set", "bytes"},
 563	[RLIMIT_NPROC] = {"Max processes", "processes"},
 564	[RLIMIT_NOFILE] = {"Max open files", "files"},
 565	[RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 566	[RLIMIT_AS] = {"Max address space", "bytes"},
 567	[RLIMIT_LOCKS] = {"Max file locks", "locks"},
 568	[RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 569	[RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 570	[RLIMIT_NICE] = {"Max nice priority", NULL},
 571	[RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 572	[RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 573};
 574
 575/* Display limits for a process */
 576static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 577			   struct pid *pid, struct task_struct *task)
 578{
 579	unsigned int i;
 580	unsigned long flags;
 581
 582	struct rlimit rlim[RLIM_NLIMITS];
 583
 584	if (!lock_task_sighand(task, &flags))
 585		return 0;
 586	memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 587	unlock_task_sighand(task, &flags);
 588
 589	/*
 590	 * print the file header
 591	 */
 592       seq_printf(m, "%-25s %-20s %-20s %-10s\n",
 593		  "Limit", "Soft Limit", "Hard Limit", "Units");
 
 
 594
 595	for (i = 0; i < RLIM_NLIMITS; i++) {
 596		if (rlim[i].rlim_cur == RLIM_INFINITY)
 597			seq_printf(m, "%-25s %-20s ",
 598				   lnames[i].name, "unlimited");
 599		else
 600			seq_printf(m, "%-25s %-20lu ",
 601				   lnames[i].name, rlim[i].rlim_cur);
 602
 603		if (rlim[i].rlim_max == RLIM_INFINITY)
 604			seq_printf(m, "%-20s ", "unlimited");
 605		else
 606			seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 607
 608		if (lnames[i].unit)
 609			seq_printf(m, "%-10s\n", lnames[i].unit);
 610		else
 611			seq_putc(m, '\n');
 612	}
 613
 614	return 0;
 615}
 616
 617#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 618static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 619			    struct pid *pid, struct task_struct *task)
 620{
 621	long nr;
 622	unsigned long args[6], sp, pc;
 623	int res;
 624
 625	res = lock_trace(task);
 626	if (res)
 627		return res;
 628
 629	if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 630		seq_puts(m, "running\n");
 631	else if (nr < 0)
 632		seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 
 633	else
 634		seq_printf(m,
 635		       "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 636		       nr,
 637		       args[0], args[1], args[2], args[3], args[4], args[5],
 638		       sp, pc);
 639	unlock_trace(task);
 640
 641	return 0;
 642}
 643#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 644
 645/************************************************************************/
 646/*                       Here the fs part begins                        */
 647/************************************************************************/
 648
 649/* permission checks */
 650static int proc_fd_access_allowed(struct inode *inode)
 651{
 652	struct task_struct *task;
 653	int allowed = 0;
 654	/* Allow access to a task's file descriptors if it is us or we
 655	 * may use ptrace attach to the process and find out that
 656	 * information.
 657	 */
 658	task = get_proc_task(inode);
 659	if (task) {
 660		allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 661		put_task_struct(task);
 662	}
 663	return allowed;
 664}
 665
 666int proc_setattr(struct dentry *dentry, struct iattr *attr)
 667{
 668	int error;
 669	struct inode *inode = d_inode(dentry);
 670
 671	if (attr->ia_valid & ATTR_MODE)
 672		return -EPERM;
 673
 674	error = setattr_prepare(dentry, attr);
 675	if (error)
 676		return error;
 677
 678	setattr_copy(inode, attr);
 679	mark_inode_dirty(inode);
 680	return 0;
 681}
 682
 683/*
 684 * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 685 * or euid/egid (for hide_pid_min=2)?
 686 */
 687static bool has_pid_permissions(struct pid_namespace *pid,
 688				 struct task_struct *task,
 689				 int hide_pid_min)
 690{
 691	if (pid->hide_pid < hide_pid_min)
 692		return true;
 693	if (in_group_p(pid->pid_gid))
 694		return true;
 695	return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 696}
 697
 698
 699static int proc_pid_permission(struct inode *inode, int mask)
 700{
 701	struct pid_namespace *pid = inode->i_sb->s_fs_info;
 702	struct task_struct *task;
 703	bool has_perms;
 704
 705	task = get_proc_task(inode);
 706	if (!task)
 707		return -ESRCH;
 708	has_perms = has_pid_permissions(pid, task, HIDEPID_NO_ACCESS);
 709	put_task_struct(task);
 710
 711	if (!has_perms) {
 712		if (pid->hide_pid == HIDEPID_INVISIBLE) {
 713			/*
 714			 * Let's make getdents(), stat(), and open()
 715			 * consistent with each other.  If a process
 716			 * may not stat() a file, it shouldn't be seen
 717			 * in procfs at all.
 718			 */
 719			return -ENOENT;
 720		}
 721
 722		return -EPERM;
 723	}
 724	return generic_permission(inode, mask);
 725}
 726
 727
 728
 729static const struct inode_operations proc_def_inode_operations = {
 730	.setattr	= proc_setattr,
 731};
 732
 733static int proc_single_show(struct seq_file *m, void *v)
 734{
 735	struct inode *inode = m->private;
 736	struct pid_namespace *ns;
 737	struct pid *pid;
 738	struct task_struct *task;
 739	int ret;
 740
 741	ns = inode->i_sb->s_fs_info;
 742	pid = proc_pid(inode);
 743	task = get_pid_task(pid, PIDTYPE_PID);
 744	if (!task)
 745		return -ESRCH;
 746
 747	ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 748
 749	put_task_struct(task);
 750	return ret;
 751}
 752
 753static int proc_single_open(struct inode *inode, struct file *filp)
 754{
 755	return single_open(filp, proc_single_show, inode);
 756}
 757
 758static const struct file_operations proc_single_file_operations = {
 759	.open		= proc_single_open,
 760	.read		= seq_read,
 761	.llseek		= seq_lseek,
 762	.release	= single_release,
 763};
 764
 765
 766struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 767{
 768	struct task_struct *task = get_proc_task(inode);
 769	struct mm_struct *mm = ERR_PTR(-ESRCH);
 770
 771	if (task) {
 772		mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 773		put_task_struct(task);
 774
 775		if (!IS_ERR_OR_NULL(mm)) {
 776			/* ensure this mm_struct can't be freed */
 777			mmgrab(mm);
 778			/* but do not pin its memory */
 779			mmput(mm);
 780		}
 781	}
 782
 783	return mm;
 784}
 785
 786static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 787{
 788	struct mm_struct *mm = proc_mem_open(inode, mode);
 789
 790	if (IS_ERR(mm))
 791		return PTR_ERR(mm);
 792
 793	file->private_data = mm;
 794	return 0;
 795}
 796
 797static int mem_open(struct inode *inode, struct file *file)
 798{
 799	int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 800
 801	/* OK to pass negative loff_t, we can catch out-of-range */
 802	file->f_mode |= FMODE_UNSIGNED_OFFSET;
 803
 804	return ret;
 805}
 806
 807static ssize_t mem_rw(struct file *file, char __user *buf,
 808			size_t count, loff_t *ppos, int write)
 809{
 810	struct mm_struct *mm = file->private_data;
 811	unsigned long addr = *ppos;
 812	ssize_t copied;
 813	char *page;
 814	unsigned int flags;
 815
 816	if (!mm)
 817		return 0;
 818
 819	page = (char *)__get_free_page(GFP_KERNEL);
 820	if (!page)
 821		return -ENOMEM;
 822
 823	copied = 0;
 824	if (!mmget_not_zero(mm))
 825		goto free;
 826
 827	flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
 828
 829	while (count > 0) {
 830		int this_len = min_t(int, count, PAGE_SIZE);
 831
 832		if (write && copy_from_user(page, buf, this_len)) {
 833			copied = -EFAULT;
 834			break;
 835		}
 836
 837		this_len = access_remote_vm(mm, addr, page, this_len, flags);
 838		if (!this_len) {
 839			if (!copied)
 840				copied = -EIO;
 841			break;
 842		}
 843
 844		if (!write && copy_to_user(buf, page, this_len)) {
 845			copied = -EFAULT;
 846			break;
 847		}
 848
 849		buf += this_len;
 850		addr += this_len;
 851		copied += this_len;
 852		count -= this_len;
 853	}
 854	*ppos = addr;
 855
 856	mmput(mm);
 857free:
 858	free_page((unsigned long) page);
 859	return copied;
 860}
 861
 862static ssize_t mem_read(struct file *file, char __user *buf,
 863			size_t count, loff_t *ppos)
 864{
 865	return mem_rw(file, buf, count, ppos, 0);
 866}
 867
 868static ssize_t mem_write(struct file *file, const char __user *buf,
 869			 size_t count, loff_t *ppos)
 870{
 871	return mem_rw(file, (char __user*)buf, count, ppos, 1);
 872}
 873
 874loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 875{
 876	switch (orig) {
 877	case 0:
 878		file->f_pos = offset;
 879		break;
 880	case 1:
 881		file->f_pos += offset;
 882		break;
 883	default:
 884		return -EINVAL;
 885	}
 886	force_successful_syscall_return();
 887	return file->f_pos;
 888}
 889
 890static int mem_release(struct inode *inode, struct file *file)
 891{
 892	struct mm_struct *mm = file->private_data;
 893	if (mm)
 894		mmdrop(mm);
 895	return 0;
 896}
 897
 898static const struct file_operations proc_mem_operations = {
 899	.llseek		= mem_lseek,
 900	.read		= mem_read,
 901	.write		= mem_write,
 902	.open		= mem_open,
 903	.release	= mem_release,
 904};
 905
 906static int environ_open(struct inode *inode, struct file *file)
 907{
 908	return __mem_open(inode, file, PTRACE_MODE_READ);
 909}
 910
 911static ssize_t environ_read(struct file *file, char __user *buf,
 912			size_t count, loff_t *ppos)
 913{
 914	char *page;
 915	unsigned long src = *ppos;
 916	int ret = 0;
 917	struct mm_struct *mm = file->private_data;
 918	unsigned long env_start, env_end;
 919
 920	/* Ensure the process spawned far enough to have an environment. */
 921	if (!mm || !mm->env_end)
 922		return 0;
 923
 924	page = (char *)__get_free_page(GFP_KERNEL);
 925	if (!page)
 926		return -ENOMEM;
 927
 928	ret = 0;
 929	if (!mmget_not_zero(mm))
 930		goto free;
 931
 932	down_read(&mm->mmap_sem);
 933	env_start = mm->env_start;
 934	env_end = mm->env_end;
 935	up_read(&mm->mmap_sem);
 936
 937	while (count > 0) {
 938		size_t this_len, max_len;
 939		int retval;
 940
 941		if (src >= (env_end - env_start))
 942			break;
 943
 944		this_len = env_end - (env_start + src);
 945
 946		max_len = min_t(size_t, PAGE_SIZE, count);
 947		this_len = min(max_len, this_len);
 948
 949		retval = access_remote_vm(mm, (env_start + src), page, this_len, FOLL_ANON);
 950
 951		if (retval <= 0) {
 952			ret = retval;
 953			break;
 954		}
 955
 956		if (copy_to_user(buf, page, retval)) {
 957			ret = -EFAULT;
 958			break;
 959		}
 960
 961		ret += retval;
 962		src += retval;
 963		buf += retval;
 964		count -= retval;
 965	}
 966	*ppos = src;
 967	mmput(mm);
 968
 969free:
 970	free_page((unsigned long) page);
 971	return ret;
 972}
 973
 974static const struct file_operations proc_environ_operations = {
 975	.open		= environ_open,
 976	.read		= environ_read,
 977	.llseek		= generic_file_llseek,
 978	.release	= mem_release,
 979};
 980
 981static int auxv_open(struct inode *inode, struct file *file)
 982{
 983	return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
 984}
 985
 986static ssize_t auxv_read(struct file *file, char __user *buf,
 987			size_t count, loff_t *ppos)
 988{
 989	struct mm_struct *mm = file->private_data;
 990	unsigned int nwords = 0;
 991
 992	if (!mm)
 993		return 0;
 994	do {
 995		nwords += 2;
 996	} while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 997	return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
 998				       nwords * sizeof(mm->saved_auxv[0]));
 999}
1000
1001static const struct file_operations proc_auxv_operations = {
1002	.open		= auxv_open,
1003	.read		= auxv_read,
1004	.llseek		= generic_file_llseek,
1005	.release	= mem_release,
1006};
1007
1008static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1009			    loff_t *ppos)
1010{
1011	struct task_struct *task = get_proc_task(file_inode(file));
1012	char buffer[PROC_NUMBUF];
1013	int oom_adj = OOM_ADJUST_MIN;
1014	size_t len;
1015
1016	if (!task)
1017		return -ESRCH;
1018	if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1019		oom_adj = OOM_ADJUST_MAX;
1020	else
1021		oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1022			  OOM_SCORE_ADJ_MAX;
1023	put_task_struct(task);
1024	len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1025	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1026}
1027
1028static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1029{
1030	static DEFINE_MUTEX(oom_adj_mutex);
1031	struct mm_struct *mm = NULL;
1032	struct task_struct *task;
1033	int err = 0;
1034
1035	task = get_proc_task(file_inode(file));
1036	if (!task)
1037		return -ESRCH;
1038
1039	mutex_lock(&oom_adj_mutex);
1040	if (legacy) {
1041		if (oom_adj < task->signal->oom_score_adj &&
1042				!capable(CAP_SYS_RESOURCE)) {
1043			err = -EACCES;
1044			goto err_unlock;
1045		}
1046		/*
1047		 * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1048		 * /proc/pid/oom_score_adj instead.
1049		 */
1050		pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1051			  current->comm, task_pid_nr(current), task_pid_nr(task),
1052			  task_pid_nr(task));
1053	} else {
1054		if ((short)oom_adj < task->signal->oom_score_adj_min &&
1055				!capable(CAP_SYS_RESOURCE)) {
1056			err = -EACCES;
1057			goto err_unlock;
1058		}
1059	}
1060
1061	/*
1062	 * Make sure we will check other processes sharing the mm if this is
1063	 * not vfrok which wants its own oom_score_adj.
1064	 * pin the mm so it doesn't go away and get reused after task_unlock
1065	 */
1066	if (!task->vfork_done) {
1067		struct task_struct *p = find_lock_task_mm(task);
1068
1069		if (p) {
1070			if (atomic_read(&p->mm->mm_users) > 1) {
1071				mm = p->mm;
1072				mmgrab(mm);
1073			}
1074			task_unlock(p);
1075		}
1076	}
1077
1078	task->signal->oom_score_adj = oom_adj;
1079	if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1080		task->signal->oom_score_adj_min = (short)oom_adj;
1081	trace_oom_score_adj_update(task);
1082
1083	if (mm) {
1084		struct task_struct *p;
1085
1086		rcu_read_lock();
1087		for_each_process(p) {
1088			if (same_thread_group(task, p))
1089				continue;
1090
1091			/* do not touch kernel threads or the global init */
1092			if (p->flags & PF_KTHREAD || is_global_init(p))
1093				continue;
1094
1095			task_lock(p);
1096			if (!p->vfork_done && process_shares_mm(p, mm)) {
1097				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",
1098						task_pid_nr(p), p->comm,
1099						p->signal->oom_score_adj, oom_adj,
1100						task_pid_nr(task), task->comm);
1101				p->signal->oom_score_adj = oom_adj;
1102				if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1103					p->signal->oom_score_adj_min = (short)oom_adj;
1104			}
1105			task_unlock(p);
1106		}
1107		rcu_read_unlock();
1108		mmdrop(mm);
1109	}
1110err_unlock:
1111	mutex_unlock(&oom_adj_mutex);
1112	put_task_struct(task);
1113	return err;
1114}
1115
1116/*
1117 * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1118 * kernels.  The effective policy is defined by oom_score_adj, which has a
1119 * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1120 * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1121 * Processes that become oom disabled via oom_adj will still be oom disabled
1122 * with this implementation.
1123 *
1124 * oom_adj cannot be removed since existing userspace binaries use it.
1125 */
1126static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1127			     size_t count, loff_t *ppos)
1128{
1129	char buffer[PROC_NUMBUF];
1130	int oom_adj;
1131	int err;
1132
1133	memset(buffer, 0, sizeof(buffer));
1134	if (count > sizeof(buffer) - 1)
1135		count = sizeof(buffer) - 1;
1136	if (copy_from_user(buffer, buf, count)) {
1137		err = -EFAULT;
1138		goto out;
1139	}
1140
1141	err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1142	if (err)
1143		goto out;
1144	if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1145	     oom_adj != OOM_DISABLE) {
1146		err = -EINVAL;
1147		goto out;
1148	}
1149
1150	/*
1151	 * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1152	 * value is always attainable.
1153	 */
1154	if (oom_adj == OOM_ADJUST_MAX)
1155		oom_adj = OOM_SCORE_ADJ_MAX;
1156	else
1157		oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1158
1159	err = __set_oom_adj(file, oom_adj, true);
1160out:
1161	return err < 0 ? err : count;
1162}
1163
1164static const struct file_operations proc_oom_adj_operations = {
1165	.read		= oom_adj_read,
1166	.write		= oom_adj_write,
1167	.llseek		= generic_file_llseek,
1168};
1169
1170static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1171					size_t count, loff_t *ppos)
1172{
1173	struct task_struct *task = get_proc_task(file_inode(file));
1174	char buffer[PROC_NUMBUF];
1175	short oom_score_adj = OOM_SCORE_ADJ_MIN;
1176	size_t len;
1177
1178	if (!task)
1179		return -ESRCH;
1180	oom_score_adj = task->signal->oom_score_adj;
1181	put_task_struct(task);
1182	len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1183	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1184}
1185
1186static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1187					size_t count, loff_t *ppos)
1188{
1189	char buffer[PROC_NUMBUF];
1190	int oom_score_adj;
1191	int err;
1192
1193	memset(buffer, 0, sizeof(buffer));
1194	if (count > sizeof(buffer) - 1)
1195		count = sizeof(buffer) - 1;
1196	if (copy_from_user(buffer, buf, count)) {
1197		err = -EFAULT;
1198		goto out;
1199	}
1200
1201	err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1202	if (err)
1203		goto out;
1204	if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1205			oom_score_adj > OOM_SCORE_ADJ_MAX) {
1206		err = -EINVAL;
1207		goto out;
1208	}
1209
1210	err = __set_oom_adj(file, oom_score_adj, false);
1211out:
1212	return err < 0 ? err : count;
1213}
1214
1215static const struct file_operations proc_oom_score_adj_operations = {
1216	.read		= oom_score_adj_read,
1217	.write		= oom_score_adj_write,
1218	.llseek		= default_llseek,
1219};
1220
1221#ifdef CONFIG_AUDITSYSCALL
1222#define TMPBUFLEN 11
1223static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1224				  size_t count, loff_t *ppos)
1225{
1226	struct inode * inode = file_inode(file);
1227	struct task_struct *task = get_proc_task(inode);
1228	ssize_t length;
1229	char tmpbuf[TMPBUFLEN];
1230
1231	if (!task)
1232		return -ESRCH;
1233	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1234			   from_kuid(file->f_cred->user_ns,
1235				     audit_get_loginuid(task)));
1236	put_task_struct(task);
1237	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1238}
1239
1240static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1241				   size_t count, loff_t *ppos)
1242{
1243	struct inode * inode = file_inode(file);
1244	uid_t loginuid;
1245	kuid_t kloginuid;
1246	int rv;
1247
1248	rcu_read_lock();
1249	if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1250		rcu_read_unlock();
1251		return -EPERM;
1252	}
1253	rcu_read_unlock();
1254
1255	if (*ppos != 0) {
1256		/* No partial writes. */
1257		return -EINVAL;
1258	}
1259
1260	rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1261	if (rv < 0)
1262		return rv;
1263
1264	/* is userspace tring to explicitly UNSET the loginuid? */
1265	if (loginuid == AUDIT_UID_UNSET) {
1266		kloginuid = INVALID_UID;
1267	} else {
1268		kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1269		if (!uid_valid(kloginuid))
1270			return -EINVAL;
1271	}
1272
1273	rv = audit_set_loginuid(kloginuid);
1274	if (rv < 0)
1275		return rv;
1276	return count;
1277}
1278
1279static const struct file_operations proc_loginuid_operations = {
1280	.read		= proc_loginuid_read,
1281	.write		= proc_loginuid_write,
1282	.llseek		= generic_file_llseek,
1283};
1284
1285static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1286				  size_t count, loff_t *ppos)
1287{
1288	struct inode * inode = file_inode(file);
1289	struct task_struct *task = get_proc_task(inode);
1290	ssize_t length;
1291	char tmpbuf[TMPBUFLEN];
1292
1293	if (!task)
1294		return -ESRCH;
1295	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1296				audit_get_sessionid(task));
1297	put_task_struct(task);
1298	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1299}
1300
1301static const struct file_operations proc_sessionid_operations = {
1302	.read		= proc_sessionid_read,
1303	.llseek		= generic_file_llseek,
1304};
1305#endif
1306
1307#ifdef CONFIG_FAULT_INJECTION
1308static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1309				      size_t count, loff_t *ppos)
1310{
1311	struct task_struct *task = get_proc_task(file_inode(file));
1312	char buffer[PROC_NUMBUF];
1313	size_t len;
1314	int make_it_fail;
1315
1316	if (!task)
1317		return -ESRCH;
1318	make_it_fail = task->make_it_fail;
1319	put_task_struct(task);
1320
1321	len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1322
1323	return simple_read_from_buffer(buf, count, ppos, buffer, len);
1324}
1325
1326static ssize_t proc_fault_inject_write(struct file * file,
1327			const char __user * buf, size_t count, loff_t *ppos)
1328{
1329	struct task_struct *task;
1330	char buffer[PROC_NUMBUF];
1331	int make_it_fail;
1332	int rv;
1333
1334	if (!capable(CAP_SYS_RESOURCE))
1335		return -EPERM;
1336	memset(buffer, 0, sizeof(buffer));
1337	if (count > sizeof(buffer) - 1)
1338		count = sizeof(buffer) - 1;
1339	if (copy_from_user(buffer, buf, count))
1340		return -EFAULT;
1341	rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1342	if (rv < 0)
1343		return rv;
1344	if (make_it_fail < 0 || make_it_fail > 1)
1345		return -EINVAL;
1346
1347	task = get_proc_task(file_inode(file));
1348	if (!task)
1349		return -ESRCH;
1350	task->make_it_fail = make_it_fail;
1351	put_task_struct(task);
1352
1353	return count;
1354}
1355
1356static const struct file_operations proc_fault_inject_operations = {
1357	.read		= proc_fault_inject_read,
1358	.write		= proc_fault_inject_write,
1359	.llseek		= generic_file_llseek,
1360};
1361
1362static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
1363				   size_t count, loff_t *ppos)
1364{
1365	struct task_struct *task;
1366	int err;
1367	unsigned int n;
1368
1369	err = kstrtouint_from_user(buf, count, 0, &n);
1370	if (err)
1371		return err;
1372
1373	task = get_proc_task(file_inode(file));
1374	if (!task)
1375		return -ESRCH;
1376	task->fail_nth = n;
1377	put_task_struct(task);
1378
1379	return count;
1380}
1381
1382static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
1383				  size_t count, loff_t *ppos)
1384{
1385	struct task_struct *task;
1386	char numbuf[PROC_NUMBUF];
1387	ssize_t len;
1388
1389	task = get_proc_task(file_inode(file));
1390	if (!task)
1391		return -ESRCH;
1392	len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
1393	len = simple_read_from_buffer(buf, count, ppos, numbuf, len);
1394	put_task_struct(task);
1395
1396	return len;
1397}
1398
1399static const struct file_operations proc_fail_nth_operations = {
1400	.read		= proc_fail_nth_read,
1401	.write		= proc_fail_nth_write,
1402};
1403#endif
1404
1405
1406#ifdef CONFIG_SCHED_DEBUG
1407/*
1408 * Print out various scheduling related per-task fields:
1409 */
1410static int sched_show(struct seq_file *m, void *v)
1411{
1412	struct inode *inode = m->private;
1413	struct pid_namespace *ns = inode->i_sb->s_fs_info;
1414	struct task_struct *p;
1415
1416	p = get_proc_task(inode);
1417	if (!p)
1418		return -ESRCH;
1419	proc_sched_show_task(p, ns, m);
1420
1421	put_task_struct(p);
1422
1423	return 0;
1424}
1425
1426static ssize_t
1427sched_write(struct file *file, const char __user *buf,
1428	    size_t count, loff_t *offset)
1429{
1430	struct inode *inode = file_inode(file);
1431	struct task_struct *p;
1432
1433	p = get_proc_task(inode);
1434	if (!p)
1435		return -ESRCH;
1436	proc_sched_set_task(p);
1437
1438	put_task_struct(p);
1439
1440	return count;
1441}
1442
1443static int sched_open(struct inode *inode, struct file *filp)
1444{
1445	return single_open(filp, sched_show, inode);
1446}
1447
1448static const struct file_operations proc_pid_sched_operations = {
1449	.open		= sched_open,
1450	.read		= seq_read,
1451	.write		= sched_write,
1452	.llseek		= seq_lseek,
1453	.release	= single_release,
1454};
1455
1456#endif
1457
1458#ifdef CONFIG_SCHED_AUTOGROUP
1459/*
1460 * Print out autogroup related information:
1461 */
1462static int sched_autogroup_show(struct seq_file *m, void *v)
1463{
1464	struct inode *inode = m->private;
1465	struct task_struct *p;
1466
1467	p = get_proc_task(inode);
1468	if (!p)
1469		return -ESRCH;
1470	proc_sched_autogroup_show_task(p, m);
1471
1472	put_task_struct(p);
1473
1474	return 0;
1475}
1476
1477static ssize_t
1478sched_autogroup_write(struct file *file, const char __user *buf,
1479	    size_t count, loff_t *offset)
1480{
1481	struct inode *inode = file_inode(file);
1482	struct task_struct *p;
1483	char buffer[PROC_NUMBUF];
1484	int nice;
1485	int err;
1486
1487	memset(buffer, 0, sizeof(buffer));
1488	if (count > sizeof(buffer) - 1)
1489		count = sizeof(buffer) - 1;
1490	if (copy_from_user(buffer, buf, count))
1491		return -EFAULT;
1492
1493	err = kstrtoint(strstrip(buffer), 0, &nice);
1494	if (err < 0)
1495		return err;
1496
1497	p = get_proc_task(inode);
1498	if (!p)
1499		return -ESRCH;
1500
1501	err = proc_sched_autogroup_set_nice(p, nice);
1502	if (err)
1503		count = err;
1504
1505	put_task_struct(p);
1506
1507	return count;
1508}
1509
1510static int sched_autogroup_open(struct inode *inode, struct file *filp)
1511{
1512	int ret;
1513
1514	ret = single_open(filp, sched_autogroup_show, NULL);
1515	if (!ret) {
1516		struct seq_file *m = filp->private_data;
1517
1518		m->private = inode;
1519	}
1520	return ret;
1521}
1522
1523static const struct file_operations proc_pid_sched_autogroup_operations = {
1524	.open		= sched_autogroup_open,
1525	.read		= seq_read,
1526	.write		= sched_autogroup_write,
1527	.llseek		= seq_lseek,
1528	.release	= single_release,
1529};
1530
1531#endif /* CONFIG_SCHED_AUTOGROUP */
1532
1533static ssize_t comm_write(struct file *file, const char __user *buf,
1534				size_t count, loff_t *offset)
1535{
1536	struct inode *inode = file_inode(file);
1537	struct task_struct *p;
1538	char buffer[TASK_COMM_LEN];
1539	const size_t maxlen = sizeof(buffer) - 1;
1540
1541	memset(buffer, 0, sizeof(buffer));
1542	if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1543		return -EFAULT;
1544
1545	p = get_proc_task(inode);
1546	if (!p)
1547		return -ESRCH;
1548
1549	if (same_thread_group(current, p))
1550		set_task_comm(p, buffer);
1551	else
1552		count = -EINVAL;
1553
1554	put_task_struct(p);
1555
1556	return count;
1557}
1558
1559static int comm_show(struct seq_file *m, void *v)
1560{
1561	struct inode *inode = m->private;
1562	struct task_struct *p;
1563
1564	p = get_proc_task(inode);
1565	if (!p)
1566		return -ESRCH;
1567
1568	task_lock(p);
1569	seq_printf(m, "%s\n", p->comm);
1570	task_unlock(p);
1571
1572	put_task_struct(p);
1573
1574	return 0;
1575}
1576
1577static int comm_open(struct inode *inode, struct file *filp)
1578{
1579	return single_open(filp, comm_show, inode);
1580}
1581
1582static const struct file_operations proc_pid_set_comm_operations = {
1583	.open		= comm_open,
1584	.read		= seq_read,
1585	.write		= comm_write,
1586	.llseek		= seq_lseek,
1587	.release	= single_release,
1588};
1589
1590static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1591{
1592	struct task_struct *task;
1593	struct file *exe_file;
1594
1595	task = get_proc_task(d_inode(dentry));
1596	if (!task)
1597		return -ENOENT;
1598	exe_file = get_task_exe_file(task);
1599	put_task_struct(task);
1600	if (exe_file) {
1601		*exe_path = exe_file->f_path;
1602		path_get(&exe_file->f_path);
1603		fput(exe_file);
1604		return 0;
1605	} else
1606		return -ENOENT;
1607}
1608
1609static const char *proc_pid_get_link(struct dentry *dentry,
1610				     struct inode *inode,
1611				     struct delayed_call *done)
1612{
1613	struct path path;
1614	int error = -EACCES;
1615
1616	if (!dentry)
1617		return ERR_PTR(-ECHILD);
1618
1619	/* Are we allowed to snoop on the tasks file descriptors? */
1620	if (!proc_fd_access_allowed(inode))
1621		goto out;
1622
1623	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1624	if (error)
1625		goto out;
1626
1627	nd_jump_link(&path);
1628	return NULL;
1629out:
1630	return ERR_PTR(error);
1631}
1632
1633static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1634{
1635	char *tmp = (char *)__get_free_page(GFP_KERNEL);
1636	char *pathname;
1637	int len;
1638
1639	if (!tmp)
1640		return -ENOMEM;
1641
1642	pathname = d_path(path, tmp, PAGE_SIZE);
1643	len = PTR_ERR(pathname);
1644	if (IS_ERR(pathname))
1645		goto out;
1646	len = tmp + PAGE_SIZE - 1 - pathname;
1647
1648	if (len > buflen)
1649		len = buflen;
1650	if (copy_to_user(buffer, pathname, len))
1651		len = -EFAULT;
1652 out:
1653	free_page((unsigned long)tmp);
1654	return len;
1655}
1656
1657static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1658{
1659	int error = -EACCES;
1660	struct inode *inode = d_inode(dentry);
1661	struct path path;
1662
1663	/* Are we allowed to snoop on the tasks file descriptors? */
1664	if (!proc_fd_access_allowed(inode))
1665		goto out;
1666
1667	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1668	if (error)
1669		goto out;
1670
1671	error = do_proc_readlink(&path, buffer, buflen);
1672	path_put(&path);
1673out:
1674	return error;
1675}
1676
1677const struct inode_operations proc_pid_link_inode_operations = {
1678	.readlink	= proc_pid_readlink,
1679	.get_link	= proc_pid_get_link,
1680	.setattr	= proc_setattr,
1681};
1682
1683
1684/* building an inode */
1685
1686void task_dump_owner(struct task_struct *task, umode_t mode,
1687		     kuid_t *ruid, kgid_t *rgid)
1688{
1689	/* Depending on the state of dumpable compute who should own a
1690	 * proc file for a task.
1691	 */
1692	const struct cred *cred;
1693	kuid_t uid;
1694	kgid_t gid;
1695
1696	if (unlikely(task->flags & PF_KTHREAD)) {
1697		*ruid = GLOBAL_ROOT_UID;
1698		*rgid = GLOBAL_ROOT_GID;
1699		return;
1700	}
1701
1702	/* Default to the tasks effective ownership */
1703	rcu_read_lock();
1704	cred = __task_cred(task);
1705	uid = cred->euid;
1706	gid = cred->egid;
1707	rcu_read_unlock();
1708
1709	/*
1710	 * Before the /proc/pid/status file was created the only way to read
1711	 * the effective uid of a /process was to stat /proc/pid.  Reading
1712	 * /proc/pid/status is slow enough that procps and other packages
1713	 * kept stating /proc/pid.  To keep the rules in /proc simple I have
1714	 * made this apply to all per process world readable and executable
1715	 * directories.
1716	 */
1717	if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
1718		struct mm_struct *mm;
1719		task_lock(task);
1720		mm = task->mm;
1721		/* Make non-dumpable tasks owned by some root */
1722		if (mm) {
1723			if (get_dumpable(mm) != SUID_DUMP_USER) {
1724				struct user_namespace *user_ns = mm->user_ns;
1725
1726				uid = make_kuid(user_ns, 0);
1727				if (!uid_valid(uid))
1728					uid = GLOBAL_ROOT_UID;
1729
1730				gid = make_kgid(user_ns, 0);
1731				if (!gid_valid(gid))
1732					gid = GLOBAL_ROOT_GID;
1733			}
1734		} else {
1735			uid = GLOBAL_ROOT_UID;
1736			gid = GLOBAL_ROOT_GID;
1737		}
1738		task_unlock(task);
1739	}
1740	*ruid = uid;
1741	*rgid = gid;
1742}
1743
1744struct inode *proc_pid_make_inode(struct super_block * sb,
1745				  struct task_struct *task, umode_t mode)
1746{
1747	struct inode * inode;
1748	struct proc_inode *ei;
1749
1750	/* We need a new inode */
1751
1752	inode = new_inode(sb);
1753	if (!inode)
1754		goto out;
1755
1756	/* Common stuff */
1757	ei = PROC_I(inode);
1758	inode->i_mode = mode;
1759	inode->i_ino = get_next_ino();
1760	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1761	inode->i_op = &proc_def_inode_operations;
1762
1763	/*
1764	 * grab the reference to task.
1765	 */
1766	ei->pid = get_task_pid(task, PIDTYPE_PID);
1767	if (!ei->pid)
1768		goto out_unlock;
1769
1770	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1771	security_task_to_inode(task, inode);
1772
1773out:
1774	return inode;
1775
1776out_unlock:
1777	iput(inode);
1778	return NULL;
1779}
1780
1781int pid_getattr(const struct path *path, struct kstat *stat,
1782		u32 request_mask, unsigned int query_flags)
1783{
1784	struct inode *inode = d_inode(path->dentry);
 
1785	struct task_struct *task;
1786	struct pid_namespace *pid = path->dentry->d_sb->s_fs_info;
1787
1788	generic_fillattr(inode, stat);
1789
1790	rcu_read_lock();
1791	stat->uid = GLOBAL_ROOT_UID;
1792	stat->gid = GLOBAL_ROOT_GID;
 
1793	task = pid_task(proc_pid(inode), PIDTYPE_PID);
1794	if (task) {
1795		if (!has_pid_permissions(pid, task, HIDEPID_INVISIBLE)) {
1796			rcu_read_unlock();
1797			/*
1798			 * This doesn't prevent learning whether PID exists,
1799			 * it only makes getattr() consistent with readdir().
1800			 */
1801			return -ENOENT;
1802		}
1803		task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
1804	}
1805	rcu_read_unlock();
1806	return 0;
1807}
1808
1809/* dentry stuff */
1810
1811/*
1812 *	Exceptional case: normally we are not allowed to unhash a busy
1813 * directory. In this case, however, we can do it - no aliasing problems
1814 * due to the way we treat inodes.
1815 *
 
 
 
 
 
 
 
1816 * Rewrite the inode's ownerships here because the owning task may have
1817 * performed a setuid(), etc.
1818 *
1819 */
1820int pid_revalidate(struct dentry *dentry, unsigned int flags)
1821{
1822	struct inode *inode;
1823	struct task_struct *task;
1824
1825	if (flags & LOOKUP_RCU)
1826		return -ECHILD;
1827
1828	inode = d_inode(dentry);
1829	task = get_proc_task(inode);
1830
1831	if (task) {
1832		task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
1833
1834		inode->i_mode &= ~(S_ISUID | S_ISGID);
1835		security_task_to_inode(task, inode);
1836		put_task_struct(task);
1837		return 1;
1838	}
1839	return 0;
1840}
1841
1842static inline bool proc_inode_is_dead(struct inode *inode)
1843{
1844	return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1845}
1846
1847int pid_delete_dentry(const struct dentry *dentry)
1848{
1849	/* Is the task we represent dead?
1850	 * If so, then don't put the dentry on the lru list,
1851	 * kill it immediately.
1852	 */
1853	return proc_inode_is_dead(d_inode(dentry));
1854}
1855
1856const struct dentry_operations pid_dentry_operations =
1857{
1858	.d_revalidate	= pid_revalidate,
1859	.d_delete	= pid_delete_dentry,
1860};
1861
1862/* Lookups */
1863
1864/*
1865 * Fill a directory entry.
1866 *
1867 * If possible create the dcache entry and derive our inode number and
1868 * file type from dcache entry.
1869 *
1870 * Since all of the proc inode numbers are dynamically generated, the inode
1871 * numbers do not exist until the inode is cache.  This means creating the
1872 * the dcache entry in readdir is necessary to keep the inode numbers
1873 * reported by readdir in sync with the inode numbers reported
1874 * by stat.
1875 */
1876bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1877	const char *name, int len,
1878	instantiate_t instantiate, struct task_struct *task, const void *ptr)
1879{
1880	struct dentry *child, *dir = file->f_path.dentry;
1881	struct qstr qname = QSTR_INIT(name, len);
1882	struct inode *inode;
1883	unsigned type;
1884	ino_t ino;
1885
1886	child = d_hash_and_lookup(dir, &qname);
1887	if (!child) {
1888		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1889		child = d_alloc_parallel(dir, &qname, &wq);
1890		if (IS_ERR(child))
1891			goto end_instantiate;
1892		if (d_in_lookup(child)) {
1893			int err = instantiate(d_inode(dir), child, task, ptr);
 
1894			d_lookup_done(child);
1895			if (err < 0) {
1896				dput(child);
1897				goto end_instantiate;
 
 
1898			}
1899		}
1900	}
1901	inode = d_inode(child);
1902	ino = inode->i_ino;
1903	type = inode->i_mode >> 12;
1904	dput(child);
1905	return dir_emit(ctx, name, len, ino, type);
1906
1907end_instantiate:
1908	return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
1909}
1910
1911/*
1912 * dname_to_vma_addr - maps a dentry name into two unsigned longs
1913 * which represent vma start and end addresses.
1914 */
1915static int dname_to_vma_addr(struct dentry *dentry,
1916			     unsigned long *start, unsigned long *end)
1917{
1918	const char *str = dentry->d_name.name;
1919	unsigned long long sval, eval;
1920	unsigned int len;
1921
1922	if (str[0] == '0' && str[1] != '-')
1923		return -EINVAL;
1924	len = _parse_integer(str, 16, &sval);
1925	if (len & KSTRTOX_OVERFLOW)
1926		return -EINVAL;
1927	if (sval != (unsigned long)sval)
1928		return -EINVAL;
1929	str += len;
1930
1931	if (*str != '-')
1932		return -EINVAL;
1933	str++;
1934
1935	if (str[0] == '0' && str[1])
1936		return -EINVAL;
1937	len = _parse_integer(str, 16, &eval);
1938	if (len & KSTRTOX_OVERFLOW)
1939		return -EINVAL;
1940	if (eval != (unsigned long)eval)
1941		return -EINVAL;
1942	str += len;
1943
1944	if (*str != '\0')
1945		return -EINVAL;
1946
1947	*start = sval;
1948	*end = eval;
1949
1950	return 0;
1951}
1952
1953static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1954{
1955	unsigned long vm_start, vm_end;
1956	bool exact_vma_exists = false;
1957	struct mm_struct *mm = NULL;
1958	struct task_struct *task;
1959	struct inode *inode;
1960	int status = 0;
1961
1962	if (flags & LOOKUP_RCU)
1963		return -ECHILD;
1964
1965	inode = d_inode(dentry);
1966	task = get_proc_task(inode);
1967	if (!task)
1968		goto out_notask;
1969
1970	mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1971	if (IS_ERR_OR_NULL(mm))
1972		goto out;
1973
1974	if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1975		down_read(&mm->mmap_sem);
1976		exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1977		up_read(&mm->mmap_sem);
 
 
 
1978	}
1979
1980	mmput(mm);
1981
1982	if (exact_vma_exists) {
1983		task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1984
1985		security_task_to_inode(task, inode);
1986		status = 1;
1987	}
1988
1989out:
1990	put_task_struct(task);
1991
1992out_notask:
1993	return status;
1994}
1995
1996static const struct dentry_operations tid_map_files_dentry_operations = {
1997	.d_revalidate	= map_files_d_revalidate,
1998	.d_delete	= pid_delete_dentry,
1999};
2000
2001static int map_files_get_link(struct dentry *dentry, struct path *path)
2002{
2003	unsigned long vm_start, vm_end;
2004	struct vm_area_struct *vma;
2005	struct task_struct *task;
2006	struct mm_struct *mm;
2007	int rc;
2008
2009	rc = -ENOENT;
2010	task = get_proc_task(d_inode(dentry));
2011	if (!task)
2012		goto out;
2013
2014	mm = get_task_mm(task);
2015	put_task_struct(task);
2016	if (!mm)
2017		goto out;
2018
2019	rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
2020	if (rc)
2021		goto out_mmput;
2022
 
 
 
 
2023	rc = -ENOENT;
2024	down_read(&mm->mmap_sem);
2025	vma = find_exact_vma(mm, vm_start, vm_end);
2026	if (vma && vma->vm_file) {
2027		*path = vma->vm_file->f_path;
2028		path_get(path);
2029		rc = 0;
2030	}
2031	up_read(&mm->mmap_sem);
2032
2033out_mmput:
2034	mmput(mm);
2035out:
2036	return rc;
2037}
2038
2039struct map_files_info {
2040	unsigned long	start;
2041	unsigned long	end;
2042	fmode_t		mode;
2043};
2044
2045/*
2046 * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
2047 * symlinks may be used to bypass permissions on ancestor directories in the
2048 * path to the file in question.
2049 */
2050static const char *
2051proc_map_files_get_link(struct dentry *dentry,
2052			struct inode *inode,
2053		        struct delayed_call *done)
2054{
2055	if (!capable(CAP_SYS_ADMIN))
2056		return ERR_PTR(-EPERM);
2057
2058	return proc_pid_get_link(dentry, inode, done);
2059}
2060
2061/*
2062 * Identical to proc_pid_link_inode_operations except for get_link()
2063 */
2064static const struct inode_operations proc_map_files_link_inode_operations = {
2065	.readlink	= proc_pid_readlink,
2066	.get_link	= proc_map_files_get_link,
2067	.setattr	= proc_setattr,
2068};
2069
2070static int
2071proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
2072			   struct task_struct *task, const void *ptr)
2073{
2074	fmode_t mode = (fmode_t)(unsigned long)ptr;
2075	struct proc_inode *ei;
2076	struct inode *inode;
2077
2078	inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK |
2079				    ((mode & FMODE_READ ) ? S_IRUSR : 0) |
2080				    ((mode & FMODE_WRITE) ? S_IWUSR : 0));
2081	if (!inode)
2082		return -ENOENT;
2083
2084	ei = PROC_I(inode);
2085	ei->op.proc_get_link = map_files_get_link;
2086
2087	inode->i_op = &proc_map_files_link_inode_operations;
2088	inode->i_size = 64;
2089
2090	d_set_d_op(dentry, &tid_map_files_dentry_operations);
2091	d_add(dentry, inode);
2092
2093	return 0;
2094}
2095
2096static struct dentry *proc_map_files_lookup(struct inode *dir,
2097		struct dentry *dentry, unsigned int flags)
2098{
2099	unsigned long vm_start, vm_end;
2100	struct vm_area_struct *vma;
2101	struct task_struct *task;
2102	int result;
2103	struct mm_struct *mm;
2104
2105	result = -ENOENT;
2106	task = get_proc_task(dir);
2107	if (!task)
2108		goto out;
2109
2110	result = -EACCES;
2111	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2112		goto out_put_task;
2113
2114	result = -ENOENT;
2115	if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2116		goto out_put_task;
2117
2118	mm = get_task_mm(task);
2119	if (!mm)
2120		goto out_put_task;
2121
2122	down_read(&mm->mmap_sem);
 
 
 
 
2123	vma = find_exact_vma(mm, vm_start, vm_end);
2124	if (!vma)
2125		goto out_no_vma;
2126
2127	if (vma->vm_file)
2128		result = proc_map_files_instantiate(dir, dentry, task,
2129				(void *)(unsigned long)vma->vm_file->f_mode);
2130
2131out_no_vma:
2132	up_read(&mm->mmap_sem);
 
2133	mmput(mm);
2134out_put_task:
2135	put_task_struct(task);
2136out:
2137	return ERR_PTR(result);
2138}
2139
2140static const struct inode_operations proc_map_files_inode_operations = {
2141	.lookup		= proc_map_files_lookup,
2142	.permission	= proc_fd_permission,
2143	.setattr	= proc_setattr,
2144};
2145
2146static int
2147proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2148{
2149	struct vm_area_struct *vma;
2150	struct task_struct *task;
2151	struct mm_struct *mm;
2152	unsigned long nr_files, pos, i;
2153	struct flex_array *fa = NULL;
2154	struct map_files_info info;
2155	struct map_files_info *p;
2156	int ret;
2157
 
 
2158	ret = -ENOENT;
2159	task = get_proc_task(file_inode(file));
2160	if (!task)
2161		goto out;
2162
2163	ret = -EACCES;
2164	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2165		goto out_put_task;
2166
2167	ret = 0;
2168	if (!dir_emit_dots(file, ctx))
2169		goto out_put_task;
2170
2171	mm = get_task_mm(task);
2172	if (!mm)
2173		goto out_put_task;
2174	down_read(&mm->mmap_sem);
 
 
 
 
 
2175
2176	nr_files = 0;
2177
2178	/*
2179	 * We need two passes here:
2180	 *
2181	 *  1) Collect vmas of mapped files with mmap_sem taken
2182	 *  2) Release mmap_sem and instantiate entries
2183	 *
2184	 * otherwise we get lockdep complained, since filldir()
2185	 * routine might require mmap_sem taken in might_fault().
2186	 */
2187
2188	for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2189		if (vma->vm_file && ++pos > ctx->pos)
2190			nr_files++;
2191	}
 
2192
2193	if (nr_files) {
2194		fa = flex_array_alloc(sizeof(info), nr_files,
2195					GFP_KERNEL);
2196		if (!fa || flex_array_prealloc(fa, 0, nr_files,
2197						GFP_KERNEL)) {
2198			ret = -ENOMEM;
2199			if (fa)
2200				flex_array_free(fa);
2201			up_read(&mm->mmap_sem);
2202			mmput(mm);
2203			goto out_put_task;
2204		}
2205		for (i = 0, vma = mm->mmap, pos = 2; vma;
2206				vma = vma->vm_next) {
2207			if (!vma->vm_file)
2208				continue;
2209			if (++pos <= ctx->pos)
2210				continue;
2211
2212			info.start = vma->vm_start;
2213			info.end = vma->vm_end;
2214			info.mode = vma->vm_file->f_mode;
2215			if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2216				BUG();
2217		}
2218	}
2219	up_read(&mm->mmap_sem);
2220	mmput(mm);
2221
2222	for (i = 0; i < nr_files; i++) {
2223		char buf[4 * sizeof(long) + 2];	/* max: %lx-%lx\0 */
2224		unsigned int len;
2225
2226		p = flex_array_get(fa, i);
2227		len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
2228		if (!proc_fill_cache(file, ctx,
2229				      buf, len,
2230				      proc_map_files_instantiate,
2231				      task,
2232				      (void *)(unsigned long)p->mode))
2233			break;
2234		ctx->pos++;
2235	}
2236	if (fa)
2237		flex_array_free(fa);
2238
2239out_put_task:
2240	put_task_struct(task);
2241out:
 
2242	return ret;
2243}
2244
2245static const struct file_operations proc_map_files_operations = {
2246	.read		= generic_read_dir,
2247	.iterate_shared	= proc_map_files_readdir,
2248	.llseek		= generic_file_llseek,
2249};
2250
2251#if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2252struct timers_private {
2253	struct pid *pid;
2254	struct task_struct *task;
2255	struct sighand_struct *sighand;
2256	struct pid_namespace *ns;
2257	unsigned long flags;
2258};
2259
2260static void *timers_start(struct seq_file *m, loff_t *pos)
2261{
2262	struct timers_private *tp = m->private;
2263
2264	tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2265	if (!tp->task)
2266		return ERR_PTR(-ESRCH);
2267
2268	tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2269	if (!tp->sighand)
2270		return ERR_PTR(-ESRCH);
2271
2272	return seq_list_start(&tp->task->signal->posix_timers, *pos);
2273}
2274
2275static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2276{
2277	struct timers_private *tp = m->private;
2278	return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2279}
2280
2281static void timers_stop(struct seq_file *m, void *v)
2282{
2283	struct timers_private *tp = m->private;
2284
2285	if (tp->sighand) {
2286		unlock_task_sighand(tp->task, &tp->flags);
2287		tp->sighand = NULL;
2288	}
2289
2290	if (tp->task) {
2291		put_task_struct(tp->task);
2292		tp->task = NULL;
2293	}
2294}
2295
2296static int show_timer(struct seq_file *m, void *v)
2297{
2298	struct k_itimer *timer;
2299	struct timers_private *tp = m->private;
2300	int notify;
2301	static const char * const nstr[] = {
2302		[SIGEV_SIGNAL] = "signal",
2303		[SIGEV_NONE] = "none",
2304		[SIGEV_THREAD] = "thread",
2305	};
2306
2307	timer = list_entry((struct list_head *)v, struct k_itimer, list);
2308	notify = timer->it_sigev_notify;
2309
2310	seq_printf(m, "ID: %d\n", timer->it_id);
2311	seq_printf(m, "signal: %d/%px\n",
2312		   timer->sigq->info.si_signo,
2313		   timer->sigq->info.si_value.sival_ptr);
2314	seq_printf(m, "notify: %s/%s.%d\n",
2315		   nstr[notify & ~SIGEV_THREAD_ID],
2316		   (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2317		   pid_nr_ns(timer->it_pid, tp->ns));
2318	seq_printf(m, "ClockID: %d\n", timer->it_clock);
2319
2320	return 0;
2321}
2322
2323static const struct seq_operations proc_timers_seq_ops = {
2324	.start	= timers_start,
2325	.next	= timers_next,
2326	.stop	= timers_stop,
2327	.show	= show_timer,
2328};
2329
2330static int proc_timers_open(struct inode *inode, struct file *file)
2331{
2332	struct timers_private *tp;
2333
2334	tp = __seq_open_private(file, &proc_timers_seq_ops,
2335			sizeof(struct timers_private));
2336	if (!tp)
2337		return -ENOMEM;
2338
2339	tp->pid = proc_pid(inode);
2340	tp->ns = inode->i_sb->s_fs_info;
2341	return 0;
2342}
2343
2344static const struct file_operations proc_timers_operations = {
2345	.open		= proc_timers_open,
2346	.read		= seq_read,
2347	.llseek		= seq_lseek,
2348	.release	= seq_release_private,
2349};
2350#endif
2351
2352static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2353					size_t count, loff_t *offset)
2354{
2355	struct inode *inode = file_inode(file);
2356	struct task_struct *p;
2357	u64 slack_ns;
2358	int err;
2359
2360	err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2361	if (err < 0)
2362		return err;
2363
2364	p = get_proc_task(inode);
2365	if (!p)
2366		return -ESRCH;
2367
2368	if (p != current) {
2369		if (!capable(CAP_SYS_NICE)) {
 
 
2370			count = -EPERM;
2371			goto out;
2372		}
 
2373
2374		err = security_task_setscheduler(p);
2375		if (err) {
2376			count = err;
2377			goto out;
2378		}
2379	}
2380
2381	task_lock(p);
2382	if (slack_ns == 0)
2383		p->timer_slack_ns = p->default_timer_slack_ns;
2384	else
2385		p->timer_slack_ns = slack_ns;
2386	task_unlock(p);
2387
2388out:
2389	put_task_struct(p);
2390
2391	return count;
2392}
2393
2394static int timerslack_ns_show(struct seq_file *m, void *v)
2395{
2396	struct inode *inode = m->private;
2397	struct task_struct *p;
2398	int err = 0;
2399
2400	p = get_proc_task(inode);
2401	if (!p)
2402		return -ESRCH;
2403
2404	if (p != current) {
2405
2406		if (!capable(CAP_SYS_NICE)) {
 
2407			err = -EPERM;
2408			goto out;
2409		}
 
 
2410		err = security_task_getscheduler(p);
2411		if (err)
2412			goto out;
2413	}
2414
2415	task_lock(p);
2416	seq_printf(m, "%llu\n", p->timer_slack_ns);
2417	task_unlock(p);
2418
2419out:
2420	put_task_struct(p);
2421
2422	return err;
2423}
2424
2425static int timerslack_ns_open(struct inode *inode, struct file *filp)
2426{
2427	return single_open(filp, timerslack_ns_show, inode);
2428}
2429
2430static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2431	.open		= timerslack_ns_open,
2432	.read		= seq_read,
2433	.write		= timerslack_ns_write,
2434	.llseek		= seq_lseek,
2435	.release	= single_release,
2436};
2437
2438static int proc_pident_instantiate(struct inode *dir,
2439	struct dentry *dentry, struct task_struct *task, const void *ptr)
2440{
2441	const struct pid_entry *p = ptr;
2442	struct inode *inode;
2443	struct proc_inode *ei;
2444
2445	inode = proc_pid_make_inode(dir->i_sb, task, p->mode);
2446	if (!inode)
2447		goto out;
2448
2449	ei = PROC_I(inode);
2450	if (S_ISDIR(inode->i_mode))
2451		set_nlink(inode, 2);	/* Use getattr to fix if necessary */
2452	if (p->iop)
2453		inode->i_op = p->iop;
2454	if (p->fop)
2455		inode->i_fop = p->fop;
2456	ei->op = p->op;
 
2457	d_set_d_op(dentry, &pid_dentry_operations);
2458	d_add(dentry, inode);
2459	/* Close the race of the process dying before we return the dentry */
2460	if (pid_revalidate(dentry, 0))
2461		return 0;
2462out:
2463	return -ENOENT;
2464}
2465
2466static struct dentry *proc_pident_lookup(struct inode *dir, 
2467					 struct dentry *dentry,
2468					 const struct pid_entry *ents,
2469					 unsigned int nents)
2470{
2471	int error;
2472	struct task_struct *task = get_proc_task(dir);
2473	const struct pid_entry *p, *last;
2474
2475	error = -ENOENT;
2476
2477	if (!task)
2478		goto out_no_task;
2479
2480	/*
2481	 * Yes, it does not scale. And it should not. Don't add
2482	 * new entries into /proc/<tgid>/ without very good reasons.
2483	 */
2484	last = &ents[nents];
2485	for (p = ents; p < last; p++) {
2486		if (p->len != dentry->d_name.len)
2487			continue;
2488		if (!memcmp(dentry->d_name.name, p->name, p->len))
 
2489			break;
 
2490	}
2491	if (p >= last)
2492		goto out;
2493
2494	error = proc_pident_instantiate(dir, dentry, task, p);
2495out:
2496	put_task_struct(task);
2497out_no_task:
2498	return ERR_PTR(error);
2499}
2500
2501static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2502		const struct pid_entry *ents, unsigned int nents)
2503{
2504	struct task_struct *task = get_proc_task(file_inode(file));
2505	const struct pid_entry *p;
2506
2507	if (!task)
2508		return -ENOENT;
2509
2510	if (!dir_emit_dots(file, ctx))
2511		goto out;
2512
2513	if (ctx->pos >= nents + 2)
2514		goto out;
2515
2516	for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
2517		if (!proc_fill_cache(file, ctx, p->name, p->len,
2518				proc_pident_instantiate, task, p))
2519			break;
2520		ctx->pos++;
2521	}
2522out:
2523	put_task_struct(task);
2524	return 0;
2525}
2526
2527#ifdef CONFIG_SECURITY
2528static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2529				  size_t count, loff_t *ppos)
2530{
2531	struct inode * inode = file_inode(file);
2532	char *p = NULL;
2533	ssize_t length;
2534	struct task_struct *task = get_proc_task(inode);
2535
2536	if (!task)
2537		return -ESRCH;
2538
2539	length = security_getprocattr(task,
2540				      (char*)file->f_path.dentry->d_name.name,
2541				      &p);
2542	put_task_struct(task);
2543	if (length > 0)
2544		length = simple_read_from_buffer(buf, count, ppos, p, length);
2545	kfree(p);
2546	return length;
2547}
2548
2549static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2550				   size_t count, loff_t *ppos)
2551{
2552	struct inode * inode = file_inode(file);
 
2553	void *page;
2554	ssize_t length;
2555	struct task_struct *task = get_proc_task(inode);
2556
2557	length = -ESRCH;
2558	if (!task)
2559		goto out_no_task;
2560
 
 
 
 
 
 
2561	/* A task may only write its own attributes. */
2562	length = -EACCES;
2563	if (current != task)
2564		goto out;
 
 
 
 
 
 
 
2565
2566	if (count > PAGE_SIZE)
2567		count = PAGE_SIZE;
2568
2569	/* No partial writes. */
2570	length = -EINVAL;
2571	if (*ppos != 0)
2572		goto out;
2573
2574	page = memdup_user(buf, count);
2575	if (IS_ERR(page)) {
2576		length = PTR_ERR(page);
2577		goto out;
2578	}
2579
2580	/* Guard against adverse ptrace interaction */
2581	length = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
2582	if (length < 0)
2583		goto out_free;
2584
2585	length = security_setprocattr(file->f_path.dentry->d_name.name,
2586				      page, count);
 
2587	mutex_unlock(&current->signal->cred_guard_mutex);
2588out_free:
2589	kfree(page);
2590out:
2591	put_task_struct(task);
2592out_no_task:
2593	return length;
2594}
2595
2596static const struct file_operations proc_pid_attr_operations = {
2597	.read		= proc_pid_attr_read,
2598	.write		= proc_pid_attr_write,
2599	.llseek		= generic_file_llseek,
2600};
2601
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2602static const struct pid_entry attr_dir_stuff[] = {
2603	REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2604	REG("prev",       S_IRUGO,	   proc_pid_attr_operations),
2605	REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2606	REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2607	REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2608	REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
 
 
 
 
2609};
2610
2611static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2612{
2613	return proc_pident_readdir(file, ctx, 
2614				   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2615}
2616
2617static const struct file_operations proc_attr_dir_operations = {
2618	.read		= generic_read_dir,
2619	.iterate_shared	= proc_attr_dir_readdir,
2620	.llseek		= generic_file_llseek,
2621};
2622
2623static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2624				struct dentry *dentry, unsigned int flags)
2625{
2626	return proc_pident_lookup(dir, dentry,
2627				  attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
 
2628}
2629
2630static const struct inode_operations proc_attr_dir_inode_operations = {
2631	.lookup		= proc_attr_dir_lookup,
2632	.getattr	= pid_getattr,
2633	.setattr	= proc_setattr,
2634};
2635
2636#endif
2637
2638#ifdef CONFIG_ELF_CORE
2639static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2640					 size_t count, loff_t *ppos)
2641{
2642	struct task_struct *task = get_proc_task(file_inode(file));
2643	struct mm_struct *mm;
2644	char buffer[PROC_NUMBUF];
2645	size_t len;
2646	int ret;
2647
2648	if (!task)
2649		return -ESRCH;
2650
2651	ret = 0;
2652	mm = get_task_mm(task);
2653	if (mm) {
2654		len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2655			       ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2656				MMF_DUMP_FILTER_SHIFT));
2657		mmput(mm);
2658		ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2659	}
2660
2661	put_task_struct(task);
2662
2663	return ret;
2664}
2665
2666static ssize_t proc_coredump_filter_write(struct file *file,
2667					  const char __user *buf,
2668					  size_t count,
2669					  loff_t *ppos)
2670{
2671	struct task_struct *task;
2672	struct mm_struct *mm;
2673	unsigned int val;
2674	int ret;
2675	int i;
2676	unsigned long mask;
2677
2678	ret = kstrtouint_from_user(buf, count, 0, &val);
2679	if (ret < 0)
2680		return ret;
2681
2682	ret = -ESRCH;
2683	task = get_proc_task(file_inode(file));
2684	if (!task)
2685		goto out_no_task;
2686
2687	mm = get_task_mm(task);
2688	if (!mm)
2689		goto out_no_mm;
2690	ret = 0;
2691
2692	for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2693		if (val & mask)
2694			set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2695		else
2696			clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2697	}
2698
2699	mmput(mm);
2700 out_no_mm:
2701	put_task_struct(task);
2702 out_no_task:
2703	if (ret < 0)
2704		return ret;
2705	return count;
2706}
2707
2708static const struct file_operations proc_coredump_filter_operations = {
2709	.read		= proc_coredump_filter_read,
2710	.write		= proc_coredump_filter_write,
2711	.llseek		= generic_file_llseek,
2712};
2713#endif
2714
2715#ifdef CONFIG_TASK_IO_ACCOUNTING
2716static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2717{
2718	struct task_io_accounting acct = task->ioac;
2719	unsigned long flags;
2720	int result;
2721
2722	result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2723	if (result)
2724		return result;
2725
2726	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2727		result = -EACCES;
2728		goto out_unlock;
2729	}
2730
2731	if (whole && lock_task_sighand(task, &flags)) {
2732		struct task_struct *t = task;
2733
2734		task_io_accounting_add(&acct, &task->signal->ioac);
2735		while_each_thread(task, t)
2736			task_io_accounting_add(&acct, &t->ioac);
2737
2738		unlock_task_sighand(task, &flags);
2739	}
2740	seq_printf(m,
2741		   "rchar: %llu\n"
2742		   "wchar: %llu\n"
2743		   "syscr: %llu\n"
2744		   "syscw: %llu\n"
2745		   "read_bytes: %llu\n"
2746		   "write_bytes: %llu\n"
2747		   "cancelled_write_bytes: %llu\n",
2748		   (unsigned long long)acct.rchar,
2749		   (unsigned long long)acct.wchar,
2750		   (unsigned long long)acct.syscr,
2751		   (unsigned long long)acct.syscw,
2752		   (unsigned long long)acct.read_bytes,
2753		   (unsigned long long)acct.write_bytes,
2754		   (unsigned long long)acct.cancelled_write_bytes);
2755	result = 0;
2756
2757out_unlock:
2758	mutex_unlock(&task->signal->cred_guard_mutex);
2759	return result;
2760}
2761
2762static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2763				  struct pid *pid, struct task_struct *task)
2764{
2765	return do_io_accounting(task, m, 0);
2766}
2767
2768static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2769				   struct pid *pid, struct task_struct *task)
2770{
2771	return do_io_accounting(task, m, 1);
2772}
2773#endif /* CONFIG_TASK_IO_ACCOUNTING */
2774
2775#ifdef CONFIG_USER_NS
2776static int proc_id_map_open(struct inode *inode, struct file *file,
2777	const struct seq_operations *seq_ops)
2778{
2779	struct user_namespace *ns = NULL;
2780	struct task_struct *task;
2781	struct seq_file *seq;
2782	int ret = -EINVAL;
2783
2784	task = get_proc_task(inode);
2785	if (task) {
2786		rcu_read_lock();
2787		ns = get_user_ns(task_cred_xxx(task, user_ns));
2788		rcu_read_unlock();
2789		put_task_struct(task);
2790	}
2791	if (!ns)
2792		goto err;
2793
2794	ret = seq_open(file, seq_ops);
2795	if (ret)
2796		goto err_put_ns;
2797
2798	seq = file->private_data;
2799	seq->private = ns;
2800
2801	return 0;
2802err_put_ns:
2803	put_user_ns(ns);
2804err:
2805	return ret;
2806}
2807
2808static int proc_id_map_release(struct inode *inode, struct file *file)
2809{
2810	struct seq_file *seq = file->private_data;
2811	struct user_namespace *ns = seq->private;
2812	put_user_ns(ns);
2813	return seq_release(inode, file);
2814}
2815
2816static int proc_uid_map_open(struct inode *inode, struct file *file)
2817{
2818	return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2819}
2820
2821static int proc_gid_map_open(struct inode *inode, struct file *file)
2822{
2823	return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2824}
2825
2826static int proc_projid_map_open(struct inode *inode, struct file *file)
2827{
2828	return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2829}
2830
2831static const struct file_operations proc_uid_map_operations = {
2832	.open		= proc_uid_map_open,
2833	.write		= proc_uid_map_write,
2834	.read		= seq_read,
2835	.llseek		= seq_lseek,
2836	.release	= proc_id_map_release,
2837};
2838
2839static const struct file_operations proc_gid_map_operations = {
2840	.open		= proc_gid_map_open,
2841	.write		= proc_gid_map_write,
2842	.read		= seq_read,
2843	.llseek		= seq_lseek,
2844	.release	= proc_id_map_release,
2845};
2846
2847static const struct file_operations proc_projid_map_operations = {
2848	.open		= proc_projid_map_open,
2849	.write		= proc_projid_map_write,
2850	.read		= seq_read,
2851	.llseek		= seq_lseek,
2852	.release	= proc_id_map_release,
2853};
2854
2855static int proc_setgroups_open(struct inode *inode, struct file *file)
2856{
2857	struct user_namespace *ns = NULL;
2858	struct task_struct *task;
2859	int ret;
2860
2861	ret = -ESRCH;
2862	task = get_proc_task(inode);
2863	if (task) {
2864		rcu_read_lock();
2865		ns = get_user_ns(task_cred_xxx(task, user_ns));
2866		rcu_read_unlock();
2867		put_task_struct(task);
2868	}
2869	if (!ns)
2870		goto err;
2871
2872	if (file->f_mode & FMODE_WRITE) {
2873		ret = -EACCES;
2874		if (!ns_capable(ns, CAP_SYS_ADMIN))
2875			goto err_put_ns;
2876	}
2877
2878	ret = single_open(file, &proc_setgroups_show, ns);
2879	if (ret)
2880		goto err_put_ns;
2881
2882	return 0;
2883err_put_ns:
2884	put_user_ns(ns);
2885err:
2886	return ret;
2887}
2888
2889static int proc_setgroups_release(struct inode *inode, struct file *file)
2890{
2891	struct seq_file *seq = file->private_data;
2892	struct user_namespace *ns = seq->private;
2893	int ret = single_release(inode, file);
2894	put_user_ns(ns);
2895	return ret;
2896}
2897
2898static const struct file_operations proc_setgroups_operations = {
2899	.open		= proc_setgroups_open,
2900	.write		= proc_setgroups_write,
2901	.read		= seq_read,
2902	.llseek		= seq_lseek,
2903	.release	= proc_setgroups_release,
2904};
2905#endif /* CONFIG_USER_NS */
2906
2907static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2908				struct pid *pid, struct task_struct *task)
2909{
2910	int err = lock_trace(task);
2911	if (!err) {
2912		seq_printf(m, "%08x\n", task->personality);
2913		unlock_trace(task);
2914	}
2915	return err;
2916}
2917
2918#ifdef CONFIG_LIVEPATCH
2919static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns,
2920				struct pid *pid, struct task_struct *task)
2921{
2922	seq_printf(m, "%d\n", task->patch_state);
2923	return 0;
2924}
2925#endif /* CONFIG_LIVEPATCH */
2926
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2927/*
2928 * Thread groups
2929 */
2930static const struct file_operations proc_task_operations;
2931static const struct inode_operations proc_task_inode_operations;
2932
2933static const struct pid_entry tgid_base_stuff[] = {
2934	DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2935	DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2936	DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2937	DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2938	DIR("ns",	  S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2939#ifdef CONFIG_NET
2940	DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2941#endif
2942	REG("environ",    S_IRUSR, proc_environ_operations),
2943	REG("auxv",       S_IRUSR, proc_auxv_operations),
2944	ONE("status",     S_IRUGO, proc_pid_status),
2945	ONE("personality", S_IRUSR, proc_pid_personality),
2946	ONE("limits",	  S_IRUGO, proc_pid_limits),
2947#ifdef CONFIG_SCHED_DEBUG
2948	REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2949#endif
2950#ifdef CONFIG_SCHED_AUTOGROUP
2951	REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2952#endif
2953	REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2954#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2955	ONE("syscall",    S_IRUSR, proc_pid_syscall),
2956#endif
2957	REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
2958	ONE("stat",       S_IRUGO, proc_tgid_stat),
2959	ONE("statm",      S_IRUGO, proc_pid_statm),
2960	REG("maps",       S_IRUGO, proc_pid_maps_operations),
2961#ifdef CONFIG_NUMA
2962	REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2963#endif
2964	REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2965	LNK("cwd",        proc_cwd_link),
2966	LNK("root",       proc_root_link),
2967	LNK("exe",        proc_exe_link),
2968	REG("mounts",     S_IRUGO, proc_mounts_operations),
2969	REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2970	REG("mountstats", S_IRUSR, proc_mountstats_operations),
2971#ifdef CONFIG_PROC_PAGE_MONITOR
2972	REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2973	REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2974	REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
2975	REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2976#endif
2977#ifdef CONFIG_SECURITY
2978	DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2979#endif
2980#ifdef CONFIG_KALLSYMS
2981	ONE("wchan",      S_IRUGO, proc_pid_wchan),
2982#endif
2983#ifdef CONFIG_STACKTRACE
2984	ONE("stack",      S_IRUSR, proc_pid_stack),
2985#endif
2986#ifdef CONFIG_SCHED_INFO
2987	ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
2988#endif
2989#ifdef CONFIG_LATENCYTOP
2990	REG("latency",  S_IRUGO, proc_lstats_operations),
2991#endif
2992#ifdef CONFIG_PROC_PID_CPUSET
2993	ONE("cpuset",     S_IRUGO, proc_cpuset_show),
2994#endif
2995#ifdef CONFIG_CGROUPS
2996	ONE("cgroup",  S_IRUGO, proc_cgroup_show),
2997#endif
2998	ONE("oom_score",  S_IRUGO, proc_oom_score),
2999	REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3000	REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3001#ifdef CONFIG_AUDITSYSCALL
3002	REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
3003	REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3004#endif
3005#ifdef CONFIG_FAULT_INJECTION
3006	REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3007	REG("fail-nth", 0644, proc_fail_nth_operations),
3008#endif
3009#ifdef CONFIG_ELF_CORE
3010	REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
3011#endif
3012#ifdef CONFIG_TASK_IO_ACCOUNTING
3013	ONE("io",	S_IRUSR, proc_tgid_io_accounting),
3014#endif
3015#ifdef CONFIG_USER_NS
3016	REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3017	REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3018	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3019	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3020#endif
3021#if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
3022	REG("timers",	  S_IRUGO, proc_timers_operations),
3023#endif
3024	REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
3025#ifdef CONFIG_LIVEPATCH
3026	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3027#endif
 
 
 
 
 
 
3028};
3029
3030static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
3031{
3032	return proc_pident_readdir(file, ctx,
3033				   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3034}
3035
3036static const struct file_operations proc_tgid_base_operations = {
3037	.read		= generic_read_dir,
3038	.iterate_shared	= proc_tgid_base_readdir,
3039	.llseek		= generic_file_llseek,
3040};
3041
 
 
 
 
 
 
 
 
3042static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3043{
3044	return proc_pident_lookup(dir, dentry,
3045				  tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
 
3046}
3047
3048static const struct inode_operations proc_tgid_base_inode_operations = {
3049	.lookup		= proc_tgid_base_lookup,
3050	.getattr	= pid_getattr,
3051	.setattr	= proc_setattr,
3052	.permission	= proc_pid_permission,
3053};
3054
3055static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
3056{
3057	struct dentry *dentry, *leader, *dir;
3058	char buf[10 + 1];
3059	struct qstr name;
3060
3061	name.name = buf;
3062	name.len = snprintf(buf, sizeof(buf), "%u", pid);
3063	/* no ->d_hash() rejects on procfs */
3064	dentry = d_hash_and_lookup(mnt->mnt_root, &name);
3065	if (dentry) {
3066		d_invalidate(dentry);
3067		dput(dentry);
3068	}
3069
3070	if (pid == tgid)
3071		return;
3072
3073	name.name = buf;
3074	name.len = snprintf(buf, sizeof(buf), "%u", tgid);
3075	leader = d_hash_and_lookup(mnt->mnt_root, &name);
3076	if (!leader)
3077		goto out;
3078
3079	name.name = "task";
3080	name.len = strlen(name.name);
3081	dir = d_hash_and_lookup(leader, &name);
3082	if (!dir)
3083		goto out_put_leader;
3084
3085	name.name = buf;
3086	name.len = snprintf(buf, sizeof(buf), "%u", pid);
3087	dentry = d_hash_and_lookup(dir, &name);
3088	if (dentry) {
3089		d_invalidate(dentry);
3090		dput(dentry);
3091	}
3092
3093	dput(dir);
3094out_put_leader:
3095	dput(leader);
3096out:
3097	return;
3098}
3099
3100/**
3101 * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
3102 * @task: task that should be flushed.
3103 *
3104 * When flushing dentries from proc, one needs to flush them from global
3105 * proc (proc_mnt) and from all the namespaces' procs this task was seen
3106 * in. This call is supposed to do all of this job.
3107 *
3108 * Looks in the dcache for
3109 * /proc/@pid
3110 * /proc/@tgid/task/@pid
3111 * if either directory is present flushes it and all of it'ts children
3112 * from the dcache.
3113 *
3114 * It is safe and reasonable to cache /proc entries for a task until
3115 * that task exits.  After that they just clog up the dcache with
3116 * useless entries, possibly causing useful dcache entries to be
3117 * flushed instead.  This routine is proved to flush those useless
3118 * dcache entries at process exit time.
3119 *
3120 * NOTE: This routine is just an optimization so it does not guarantee
3121 *       that no dcache entries will exist at process exit time it
3122 *       just makes it very unlikely that any will persist.
3123 */
3124
3125void proc_flush_task(struct task_struct *task)
3126{
3127	int i;
3128	struct pid *pid, *tgid;
3129	struct upid *upid;
3130
3131	pid = task_pid(task);
3132	tgid = task_tgid(task);
3133
3134	for (i = 0; i <= pid->level; i++) {
3135		upid = &pid->numbers[i];
3136		proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3137					tgid->numbers[i].nr);
3138	}
3139}
3140
3141static int proc_pid_instantiate(struct inode *dir,
3142				   struct dentry * dentry,
3143				   struct task_struct *task, const void *ptr)
3144{
3145	struct inode *inode;
3146
3147	inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3148	if (!inode)
3149		goto out;
3150
3151	inode->i_op = &proc_tgid_base_inode_operations;
3152	inode->i_fop = &proc_tgid_base_operations;
3153	inode->i_flags|=S_IMMUTABLE;
3154
3155	set_nlink(inode, nlink_tgid);
 
3156
3157	d_set_d_op(dentry, &pid_dentry_operations);
3158
3159	d_add(dentry, inode);
3160	/* Close the race of the process dying before we return the dentry */
3161	if (pid_revalidate(dentry, 0))
3162		return 0;
3163out:
3164	return -ENOENT;
3165}
3166
3167struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3168{
3169	int result = -ENOENT;
3170	struct task_struct *task;
3171	unsigned tgid;
3172	struct pid_namespace *ns;
 
3173
3174	tgid = name_to_int(&dentry->d_name);
3175	if (tgid == ~0U)
3176		goto out;
3177
3178	ns = dentry->d_sb->s_fs_info;
3179	rcu_read_lock();
3180	task = find_task_by_pid_ns(tgid, ns);
3181	if (task)
3182		get_task_struct(task);
3183	rcu_read_unlock();
3184	if (!task)
3185		goto out;
3186
3187	result = proc_pid_instantiate(dir, dentry, task, NULL);
3188	put_task_struct(task);
3189out:
3190	return ERR_PTR(result);
3191}
3192
3193/*
3194 * Find the first task with tgid >= tgid
3195 *
3196 */
3197struct tgid_iter {
3198	unsigned int tgid;
3199	struct task_struct *task;
3200};
3201static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3202{
3203	struct pid *pid;
3204
3205	if (iter.task)
3206		put_task_struct(iter.task);
3207	rcu_read_lock();
3208retry:
3209	iter.task = NULL;
3210	pid = find_ge_pid(iter.tgid, ns);
3211	if (pid) {
3212		iter.tgid = pid_nr_ns(pid, ns);
3213		iter.task = pid_task(pid, PIDTYPE_PID);
3214		/* What we to know is if the pid we have find is the
3215		 * pid of a thread_group_leader.  Testing for task
3216		 * being a thread_group_leader is the obvious thing
3217		 * todo but there is a window when it fails, due to
3218		 * the pid transfer logic in de_thread.
3219		 *
3220		 * So we perform the straight forward test of seeing
3221		 * if the pid we have found is the pid of a thread
3222		 * group leader, and don't worry if the task we have
3223		 * found doesn't happen to be a thread group leader.
3224		 * As we don't care in the case of readdir.
3225		 */
3226		if (!iter.task || !has_group_leader_pid(iter.task)) {
3227			iter.tgid += 1;
3228			goto retry;
3229		}
3230		get_task_struct(iter.task);
3231	}
3232	rcu_read_unlock();
3233	return iter;
3234}
3235
3236#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3237
3238/* for the /proc/ directory itself, after non-process stuff has been done */
3239int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3240{
3241	struct tgid_iter iter;
3242	struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info;
3243	loff_t pos = ctx->pos;
3244
3245	if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3246		return 0;
3247
3248	if (pos == TGID_OFFSET - 2) {
3249		struct inode *inode = d_inode(ns->proc_self);
3250		if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3251			return 0;
3252		ctx->pos = pos = pos + 1;
3253	}
3254	if (pos == TGID_OFFSET - 1) {
3255		struct inode *inode = d_inode(ns->proc_thread_self);
3256		if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3257			return 0;
3258		ctx->pos = pos = pos + 1;
3259	}
3260	iter.tgid = pos - TGID_OFFSET;
3261	iter.task = NULL;
3262	for (iter = next_tgid(ns, iter);
3263	     iter.task;
3264	     iter.tgid += 1, iter = next_tgid(ns, iter)) {
3265		char name[10 + 1];
3266		int len;
3267
3268		cond_resched();
3269		if (!has_pid_permissions(ns, iter.task, HIDEPID_INVISIBLE))
3270			continue;
3271
3272		len = snprintf(name, sizeof(name), "%u", iter.tgid);
3273		ctx->pos = iter.tgid + TGID_OFFSET;
3274		if (!proc_fill_cache(file, ctx, name, len,
3275				     proc_pid_instantiate, iter.task, NULL)) {
3276			put_task_struct(iter.task);
3277			return 0;
3278		}
3279	}
3280	ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3281	return 0;
3282}
3283
3284/*
3285 * proc_tid_comm_permission is a special permission function exclusively
3286 * used for the node /proc/<pid>/task/<tid>/comm.
3287 * It bypasses generic permission checks in the case where a task of the same
3288 * task group attempts to access the node.
3289 * The rationale behind this is that glibc and bionic access this node for
3290 * cross thread naming (pthread_set/getname_np(!self)). However, if
3291 * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3292 * which locks out the cross thread naming implementation.
3293 * This function makes sure that the node is always accessible for members of
3294 * same thread group.
3295 */
3296static int proc_tid_comm_permission(struct inode *inode, int mask)
3297{
3298	bool is_same_tgroup;
3299	struct task_struct *task;
3300
3301	task = get_proc_task(inode);
3302	if (!task)
3303		return -ESRCH;
3304	is_same_tgroup = same_thread_group(current, task);
3305	put_task_struct(task);
3306
3307	if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3308		/* This file (/proc/<pid>/task/<tid>/comm) can always be
3309		 * read or written by the members of the corresponding
3310		 * thread group.
3311		 */
3312		return 0;
3313	}
3314
3315	return generic_permission(inode, mask);
3316}
3317
3318static const struct inode_operations proc_tid_comm_inode_operations = {
3319		.permission = proc_tid_comm_permission,
3320};
3321
3322/*
3323 * Tasks
3324 */
3325static const struct pid_entry tid_base_stuff[] = {
3326	DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3327	DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3328	DIR("ns",	 S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3329#ifdef CONFIG_NET
3330	DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3331#endif
3332	REG("environ",   S_IRUSR, proc_environ_operations),
3333	REG("auxv",      S_IRUSR, proc_auxv_operations),
3334	ONE("status",    S_IRUGO, proc_pid_status),
3335	ONE("personality", S_IRUSR, proc_pid_personality),
3336	ONE("limits",	 S_IRUGO, proc_pid_limits),
3337#ifdef CONFIG_SCHED_DEBUG
3338	REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3339#endif
3340	NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3341			 &proc_tid_comm_inode_operations,
3342			 &proc_pid_set_comm_operations, {}),
3343#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3344	ONE("syscall",   S_IRUSR, proc_pid_syscall),
3345#endif
3346	REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3347	ONE("stat",      S_IRUGO, proc_tid_stat),
3348	ONE("statm",     S_IRUGO, proc_pid_statm),
3349	REG("maps",      S_IRUGO, proc_tid_maps_operations),
3350#ifdef CONFIG_PROC_CHILDREN
3351	REG("children",  S_IRUGO, proc_tid_children_operations),
3352#endif
3353#ifdef CONFIG_NUMA
3354	REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3355#endif
3356	REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3357	LNK("cwd",       proc_cwd_link),
3358	LNK("root",      proc_root_link),
3359	LNK("exe",       proc_exe_link),
3360	REG("mounts",    S_IRUGO, proc_mounts_operations),
3361	REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3362#ifdef CONFIG_PROC_PAGE_MONITOR
3363	REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3364	REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3365	REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3366	REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3367#endif
3368#ifdef CONFIG_SECURITY
3369	DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3370#endif
3371#ifdef CONFIG_KALLSYMS
3372	ONE("wchan",     S_IRUGO, proc_pid_wchan),
3373#endif
3374#ifdef CONFIG_STACKTRACE
3375	ONE("stack",      S_IRUSR, proc_pid_stack),
3376#endif
3377#ifdef CONFIG_SCHED_INFO
3378	ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3379#endif
3380#ifdef CONFIG_LATENCYTOP
3381	REG("latency",  S_IRUGO, proc_lstats_operations),
3382#endif
3383#ifdef CONFIG_PROC_PID_CPUSET
3384	ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3385#endif
3386#ifdef CONFIG_CGROUPS
3387	ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3388#endif
3389	ONE("oom_score", S_IRUGO, proc_oom_score),
3390	REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3391	REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3392#ifdef CONFIG_AUDITSYSCALL
3393	REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3394	REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3395#endif
3396#ifdef CONFIG_FAULT_INJECTION
3397	REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3398	REG("fail-nth", 0644, proc_fail_nth_operations),
3399#endif
3400#ifdef CONFIG_TASK_IO_ACCOUNTING
3401	ONE("io",	S_IRUSR, proc_tid_io_accounting),
3402#endif
3403#ifdef CONFIG_USER_NS
3404	REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3405	REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3406	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3407	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3408#endif
3409#ifdef CONFIG_LIVEPATCH
3410	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3411#endif
 
 
 
3412};
3413
3414static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3415{
3416	return proc_pident_readdir(file, ctx,
3417				   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3418}
3419
3420static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3421{
3422	return proc_pident_lookup(dir, dentry,
3423				  tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
 
3424}
3425
3426static const struct file_operations proc_tid_base_operations = {
3427	.read		= generic_read_dir,
3428	.iterate_shared	= proc_tid_base_readdir,
3429	.llseek		= generic_file_llseek,
3430};
3431
3432static const struct inode_operations proc_tid_base_inode_operations = {
3433	.lookup		= proc_tid_base_lookup,
3434	.getattr	= pid_getattr,
3435	.setattr	= proc_setattr,
3436};
3437
3438static int proc_task_instantiate(struct inode *dir,
3439	struct dentry *dentry, struct task_struct *task, const void *ptr)
3440{
3441	struct inode *inode;
3442	inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3443
3444	if (!inode)
3445		goto out;
 
3446	inode->i_op = &proc_tid_base_inode_operations;
3447	inode->i_fop = &proc_tid_base_operations;
3448	inode->i_flags|=S_IMMUTABLE;
3449
3450	set_nlink(inode, nlink_tid);
 
3451
3452	d_set_d_op(dentry, &pid_dentry_operations);
3453
3454	d_add(dentry, inode);
3455	/* Close the race of the process dying before we return the dentry */
3456	if (pid_revalidate(dentry, 0))
3457		return 0;
3458out:
3459	return -ENOENT;
3460}
3461
3462static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3463{
3464	int result = -ENOENT;
3465	struct task_struct *task;
3466	struct task_struct *leader = get_proc_task(dir);
3467	unsigned tid;
3468	struct pid_namespace *ns;
 
3469
3470	if (!leader)
3471		goto out_no_task;
3472
3473	tid = name_to_int(&dentry->d_name);
3474	if (tid == ~0U)
3475		goto out;
3476
3477	ns = dentry->d_sb->s_fs_info;
3478	rcu_read_lock();
3479	task = find_task_by_pid_ns(tid, ns);
3480	if (task)
3481		get_task_struct(task);
3482	rcu_read_unlock();
3483	if (!task)
3484		goto out;
3485	if (!same_thread_group(leader, task))
3486		goto out_drop_task;
3487
3488	result = proc_task_instantiate(dir, dentry, task, NULL);
3489out_drop_task:
3490	put_task_struct(task);
3491out:
3492	put_task_struct(leader);
3493out_no_task:
3494	return ERR_PTR(result);
3495}
3496
3497/*
3498 * Find the first tid of a thread group to return to user space.
3499 *
3500 * Usually this is just the thread group leader, but if the users
3501 * buffer was too small or there was a seek into the middle of the
3502 * directory we have more work todo.
3503 *
3504 * In the case of a short read we start with find_task_by_pid.
3505 *
3506 * In the case of a seek we start with the leader and walk nr
3507 * threads past it.
3508 */
3509static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3510					struct pid_namespace *ns)
3511{
3512	struct task_struct *pos, *task;
3513	unsigned long nr = f_pos;
3514
3515	if (nr != f_pos)	/* 32bit overflow? */
3516		return NULL;
3517
3518	rcu_read_lock();
3519	task = pid_task(pid, PIDTYPE_PID);
3520	if (!task)
3521		goto fail;
3522
3523	/* Attempt to start with the tid of a thread */
3524	if (tid && nr) {
3525		pos = find_task_by_pid_ns(tid, ns);
3526		if (pos && same_thread_group(pos, task))
3527			goto found;
3528	}
3529
3530	/* If nr exceeds the number of threads there is nothing todo */
3531	if (nr >= get_nr_threads(task))
3532		goto fail;
3533
3534	/* If we haven't found our starting place yet start
3535	 * with the leader and walk nr threads forward.
3536	 */
3537	pos = task = task->group_leader;
3538	do {
3539		if (!nr--)
3540			goto found;
3541	} while_each_thread(task, pos);
3542fail:
3543	pos = NULL;
3544	goto out;
3545found:
3546	get_task_struct(pos);
3547out:
3548	rcu_read_unlock();
3549	return pos;
3550}
3551
3552/*
3553 * Find the next thread in the thread list.
3554 * Return NULL if there is an error or no next thread.
3555 *
3556 * The reference to the input task_struct is released.
3557 */
3558static struct task_struct *next_tid(struct task_struct *start)
3559{
3560	struct task_struct *pos = NULL;
3561	rcu_read_lock();
3562	if (pid_alive(start)) {
3563		pos = next_thread(start);
3564		if (thread_group_leader(pos))
3565			pos = NULL;
3566		else
3567			get_task_struct(pos);
3568	}
3569	rcu_read_unlock();
3570	put_task_struct(start);
3571	return pos;
3572}
3573
3574/* for the /proc/TGID/task/ directories */
3575static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3576{
3577	struct inode *inode = file_inode(file);
3578	struct task_struct *task;
3579	struct pid_namespace *ns;
3580	int tid;
3581
3582	if (proc_inode_is_dead(inode))
3583		return -ENOENT;
3584
3585	if (!dir_emit_dots(file, ctx))
3586		return 0;
3587
3588	/* f_version caches the tgid value that the last readdir call couldn't
3589	 * return. lseek aka telldir automagically resets f_version to 0.
3590	 */
3591	ns = inode->i_sb->s_fs_info;
3592	tid = (int)file->f_version;
3593	file->f_version = 0;
3594	for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3595	     task;
3596	     task = next_tid(task), ctx->pos++) {
3597		char name[10 + 1];
3598		int len;
3599		tid = task_pid_nr_ns(task, ns);
3600		len = snprintf(name, sizeof(name), "%u", tid);
3601		if (!proc_fill_cache(file, ctx, name, len,
3602				proc_task_instantiate, task, NULL)) {
3603			/* returning this tgid failed, save it as the first
3604			 * pid for the next readir call */
3605			file->f_version = (u64)tid;
3606			put_task_struct(task);
3607			break;
3608		}
3609	}
3610
3611	return 0;
3612}
3613
3614static int proc_task_getattr(const struct path *path, struct kstat *stat,
3615			     u32 request_mask, unsigned int query_flags)
3616{
3617	struct inode *inode = d_inode(path->dentry);
3618	struct task_struct *p = get_proc_task(inode);
3619	generic_fillattr(inode, stat);
3620
3621	if (p) {
3622		stat->nlink += get_nr_threads(p);
3623		put_task_struct(p);
3624	}
3625
3626	return 0;
3627}
3628
3629static const struct inode_operations proc_task_inode_operations = {
3630	.lookup		= proc_task_lookup,
3631	.getattr	= proc_task_getattr,
3632	.setattr	= proc_setattr,
3633	.permission	= proc_pid_permission,
3634};
3635
3636static const struct file_operations proc_task_operations = {
3637	.read		= generic_read_dir,
3638	.iterate_shared	= proc_task_readdir,
3639	.llseek		= generic_file_llseek,
3640};
3641
3642void __init set_proc_pid_nlink(void)
3643{
3644	nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3645	nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3646}