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