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