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(d_inode(dentry));
 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(d_inode(dentry));
 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 ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 200                                     size_t _count, loff_t *pos)
 201{
 202        struct task_struct *tsk;
 203        struct mm_struct *mm;
 204        char *page;
 205        unsigned long count = _count;
 206        unsigned long arg_start, arg_end, env_start, env_end;
 207        unsigned long len1, len2, len;
 208        unsigned long p;
 209        char c;
 210        ssize_t rv;
 211
 212        BUG_ON(*pos < 0);
 213
 214        tsk = get_proc_task(file_inode(file));
 215        if (!tsk)
 216                return -ESRCH;
 217        mm = get_task_mm(tsk);
 218        put_task_struct(tsk);
 219        if (!mm)
 220                return 0;
 221        /* Check if process spawned far enough to have cmdline. */
 222        if (!mm->env_end) {
 223                rv = 0;
 224                goto out_mmput;
 225        }
 226
 227        page = (char *)__get_free_page(GFP_TEMPORARY);
 228        if (!page) {
 229                rv = -ENOMEM;
 230                goto out_mmput;
 231        }
 232
 233        down_read(&mm->mmap_sem);
 234        arg_start = mm->arg_start;
 235        arg_end = mm->arg_end;
 236        env_start = mm->env_start;
 237        env_end = mm->env_end;
 238        up_read(&mm->mmap_sem);
 239
 240        BUG_ON(arg_start > arg_end);
 241        BUG_ON(env_start > env_end);
 242
 243        len1 = arg_end - arg_start;
 244        len2 = env_end - env_start;
 245
 246        /* Empty ARGV. */
 247        if (len1 == 0) {
 248                rv = 0;
 249                goto out_free_page;
 250        }
 251        /*
 252         * Inherently racy -- command line shares address space
 253         * with code and data.
 254         */
 255        rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0);
 256        if (rv <= 0)
 257                goto out_free_page;
 258
 259        rv = 0;
 260
 261        if (c == '\0') {
 262                /* Command line (set of strings) occupies whole ARGV. */
 263                if (len1 <= *pos)
 264                        goto out_free_page;
 265
 266                p = arg_start + *pos;
 267                len = len1 - *pos;
 268                while (count > 0 && len > 0) {
 269                        unsigned int _count;
 270                        int nr_read;
 271
 272                        _count = min3(count, len, PAGE_SIZE);
 273                        nr_read = access_remote_vm(mm, p, page, _count, 0);
 274                        if (nr_read < 0)
 275                                rv = nr_read;
 276                        if (nr_read <= 0)
 277                                goto out_free_page;
 278
 279                        if (copy_to_user(buf, page, nr_read)) {
 280                                rv = -EFAULT;
 281                                goto out_free_page;
 282                        }
 283
 284                        p       += nr_read;
 285                        len     -= nr_read;
 286                        buf     += nr_read;
 287                        count   -= nr_read;
 288                        rv      += nr_read;
 289                }
 290        } else {
 291                /*
 292                 * Command line (1 string) occupies ARGV and maybe
 293                 * extends into ENVP.
 294                 */
 295                if (len1 + len2 <= *pos)
 296                        goto skip_argv_envp;
 297                if (len1 <= *pos)
 298                        goto skip_argv;
 299
 300                p = arg_start + *pos;
 301                len = len1 - *pos;
 302                while (count > 0 && len > 0) {
 303                        unsigned int _count, l;
 304                        int nr_read;
 305                        bool final;
 306
 307                        _count = min3(count, len, PAGE_SIZE);
 308                        nr_read = access_remote_vm(mm, p, page, _count, 0);
 309                        if (nr_read < 0)
 310                                rv = nr_read;
 311                        if (nr_read <= 0)
 312                                goto out_free_page;
 313
 314                        /*
 315                         * Command line can be shorter than whole ARGV
 316                         * even if last "marker" byte says it is not.
 317                         */
 318                        final = false;
 319                        l = strnlen(page, nr_read);
 320                        if (l < nr_read) {
 321                                nr_read = l;
 322                                final = true;
 323                        }
 324
 325                        if (copy_to_user(buf, page, nr_read)) {
 326                                rv = -EFAULT;
 327                                goto out_free_page;
 328                        }
 329
 330                        p       += nr_read;
 331                        len     -= nr_read;
 332                        buf     += nr_read;
 333                        count   -= nr_read;
 334                        rv      += nr_read;
 335
 336                        if (final)
 337                                goto out_free_page;
 338                }
 339skip_argv:
 340                /*
 341                 * Command line (1 string) occupies ARGV and
 342                 * extends into ENVP.
 343                 */
 344                if (len1 <= *pos) {
 345                        p = env_start + *pos - len1;
 346                        len = len1 + len2 - *pos;
 347                } else {
 348                        p = env_start;
 349                        len = len2;
 350                }
 351                while (count > 0 && len > 0) {
 352                        unsigned int _count, l;
 353                        int nr_read;
 354                        bool final;
 355
 356                        _count = min3(count, len, PAGE_SIZE);
 357                        nr_read = access_remote_vm(mm, p, page, _count, 0);
 358                        if (nr_read < 0)
 359                                rv = nr_read;
 360                        if (nr_read <= 0)
 361                                goto out_free_page;
 362
 363                        /* Find EOS. */
 364                        final = false;
 365                        l = strnlen(page, nr_read);
 366                        if (l < nr_read) {
 367                                nr_read = l;
 368                                final = true;
 369                        }
 370
 371                        if (copy_to_user(buf, page, nr_read)) {
 372                                rv = -EFAULT;
 373                                goto out_free_page;
 374                        }
 375
 376                        p       += nr_read;
 377                        len     -= nr_read;
 378                        buf     += nr_read;
 379                        count   -= nr_read;
 380                        rv      += nr_read;
 381
 382                        if (final)
 383                                goto out_free_page;
 384                }
 385skip_argv_envp:
 386                ;
 387        }
 388
 389out_free_page:
 390        free_page((unsigned long)page);
 391out_mmput:
 392        mmput(mm);
 393        if (rv > 0)
 394                *pos += rv;
 395        return rv;
 396}
 397
 398static const struct file_operations proc_pid_cmdline_ops = {
 399        .read   = proc_pid_cmdline_read,
 400        .llseek = generic_file_llseek,
 401};
 402
 403static int proc_pid_auxv(struct seq_file *m, struct pid_namespace *ns,
 404                         struct pid *pid, struct task_struct *task)
 405{
 406        struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
 407        if (mm && !IS_ERR(mm)) {
 408                unsigned int nwords = 0;
 409                do {
 410                        nwords += 2;
 411                } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 412                seq_write(m, mm->saved_auxv, nwords * sizeof(mm->saved_auxv[0]));
 413                mmput(mm);
 414                return 0;
 415        } else
 416                return PTR_ERR(mm);
 417}
 418
 419
 420#ifdef CONFIG_KALLSYMS
 421/*
 422 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 423 * Returns the resolved symbol.  If that fails, simply return the address.
 424 */
 425static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 426                          struct pid *pid, struct task_struct *task)
 427{
 428        unsigned long wchan;
 429        char symname[KSYM_NAME_LEN];
 430
 431        wchan = get_wchan(task);
 432
 433        if (wchan && ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)
 434                        && !lookup_symbol_name(wchan, symname))
 435                seq_printf(m, "%s", symname);
 436        else
 437                seq_putc(m, '0');
 438
 439        return 0;
 440}
 441#endif /* CONFIG_KALLSYMS */
 442
 443static int lock_trace(struct task_struct *task)
 444{
 445        int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 446        if (err)
 447                return err;
 448        if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 449                mutex_unlock(&task->signal->cred_guard_mutex);
 450                return -EPERM;
 451        }
 452        return 0;
 453}
 454
 455static void unlock_trace(struct task_struct *task)
 456{
 457        mutex_unlock(&task->signal->cred_guard_mutex);
 458}
 459
 460#ifdef CONFIG_STACKTRACE
 461
 462#define MAX_STACK_TRACE_DEPTH   64
 463
 464static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 465                          struct pid *pid, struct task_struct *task)
 466{
 467        struct stack_trace trace;
 468        unsigned long *entries;
 469        int err;
 470        int i;
 471
 472        entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 473        if (!entries)
 474                return -ENOMEM;
 475
 476        trace.nr_entries        = 0;
 477        trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 478        trace.entries           = entries;
 479        trace.skip              = 0;
 480
 481        err = lock_trace(task);
 482        if (!err) {
 483                save_stack_trace_tsk(task, &trace);
 484
 485                for (i = 0; i < trace.nr_entries; i++) {
 486                        seq_printf(m, "[<%pK>] %pS\n",
 487                                   (void *)entries[i], (void *)entries[i]);
 488                }
 489                unlock_trace(task);
 490        }
 491        kfree(entries);
 492
 493        return err;
 494}
 495#endif
 496
 497#ifdef CONFIG_SCHED_INFO
 498/*
 499 * Provides /proc/PID/schedstat
 500 */
 501static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 502                              struct pid *pid, struct task_struct *task)
 503{
 504        if (unlikely(!sched_info_on()))
 505                seq_printf(m, "0 0 0\n");
 506        else
 507                seq_printf(m, "%llu %llu %lu\n",
 508                   (unsigned long long)task->se.sum_exec_runtime,
 509                   (unsigned long long)task->sched_info.run_delay,
 510                   task->sched_info.pcount);
 511
 512        return 0;
 513}
 514#endif
 515
 516#ifdef CONFIG_LATENCYTOP
 517static int lstats_show_proc(struct seq_file *m, void *v)
 518{
 519        int i;
 520        struct inode *inode = m->private;
 521        struct task_struct *task = get_proc_task(inode);
 522
 523        if (!task)
 524                return -ESRCH;
 525        seq_puts(m, "Latency Top version : v0.1\n");
 526        for (i = 0; i < 32; i++) {
 527                struct latency_record *lr = &task->latency_record[i];
 528                if (lr->backtrace[0]) {
 529                        int q;
 530                        seq_printf(m, "%i %li %li",
 531                                   lr->count, lr->time, lr->max);
 532                        for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 533                                unsigned long bt = lr->backtrace[q];
 534                                if (!bt)
 535                                        break;
 536                                if (bt == ULONG_MAX)
 537                                        break;
 538                                seq_printf(m, " %ps", (void *)bt);
 539                        }
 540                        seq_putc(m, '\n');
 541                }
 542
 543        }
 544        put_task_struct(task);
 545        return 0;
 546}
 547
 548static int lstats_open(struct inode *inode, struct file *file)
 549{
 550        return single_open(file, lstats_show_proc, inode);
 551}
 552
 553static ssize_t lstats_write(struct file *file, const char __user *buf,
 554                            size_t count, loff_t *offs)
 555{
 556        struct task_struct *task = get_proc_task(file_inode(file));
 557
 558        if (!task)
 559                return -ESRCH;
 560        clear_all_latency_tracing(task);
 561        put_task_struct(task);
 562
 563        return count;
 564}
 565
 566static const struct file_operations proc_lstats_operations = {
 567        .open           = lstats_open,
 568        .read           = seq_read,
 569        .write          = lstats_write,
 570        .llseek         = seq_lseek,
 571        .release        = single_release,
 572};
 573
 574#endif
 575
 576static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 577                          struct pid *pid, struct task_struct *task)
 578{
 579        unsigned long totalpages = totalram_pages + total_swap_pages;
 580        unsigned long points = 0;
 581
 582        points = oom_badness(task, NULL, NULL, totalpages) *
 583                                        1000 / totalpages;
 584        seq_printf(m, "%lu\n", points);
 585
 586        return 0;
 587}
 588
 589struct limit_names {
 590        const char *name;
 591        const char *unit;
 592};
 593
 594static const struct limit_names lnames[RLIM_NLIMITS] = {
 595        [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 596        [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 597        [RLIMIT_DATA] = {"Max data size", "bytes"},
 598        [RLIMIT_STACK] = {"Max stack size", "bytes"},
 599        [RLIMIT_CORE] = {"Max core file size", "bytes"},
 600        [RLIMIT_RSS] = {"Max resident set", "bytes"},
 601        [RLIMIT_NPROC] = {"Max processes", "processes"},
 602        [RLIMIT_NOFILE] = {"Max open files", "files"},
 603        [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 604        [RLIMIT_AS] = {"Max address space", "bytes"},
 605        [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 606        [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 607        [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 608        [RLIMIT_NICE] = {"Max nice priority", NULL},
 609        [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 610        [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 611};
 612
 613/* Display limits for a process */
 614static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 615                           struct pid *pid, struct task_struct *task)
 616{
 617        unsigned int i;
 618        unsigned long flags;
 619
 620        struct rlimit rlim[RLIM_NLIMITS];
 621
 622        if (!lock_task_sighand(task, &flags))
 623                return 0;
 624        memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 625        unlock_task_sighand(task, &flags);
 626
 627        /*
 628         * print the file header
 629         */
 630       seq_printf(m, "%-25s %-20s %-20s %-10s\n",
 631                  "Limit", "Soft Limit", "Hard Limit", "Units");
 632
 633        for (i = 0; i < RLIM_NLIMITS; i++) {
 634                if (rlim[i].rlim_cur == RLIM_INFINITY)
 635                        seq_printf(m, "%-25s %-20s ",
 636                                   lnames[i].name, "unlimited");
 637                else
 638                        seq_printf(m, "%-25s %-20lu ",
 639                                   lnames[i].name, rlim[i].rlim_cur);
 640
 641                if (rlim[i].rlim_max == RLIM_INFINITY)
 642                        seq_printf(m, "%-20s ", "unlimited");
 643                else
 644                        seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 645
 646                if (lnames[i].unit)
 647                        seq_printf(m, "%-10s\n", lnames[i].unit);
 648                else
 649                        seq_putc(m, '\n');
 650        }
 651
 652        return 0;
 653}
 654
 655#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 656static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 657                            struct pid *pid, struct task_struct *task)
 658{
 659        long nr;
 660        unsigned long args[6], sp, pc;
 661        int res;
 662
 663        res = lock_trace(task);
 664        if (res)
 665                return res;
 666
 667        if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 668                seq_puts(m, "running\n");
 669        else if (nr < 0)
 670                seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 671        else
 672                seq_printf(m,
 673                       "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 674                       nr,
 675                       args[0], args[1], args[2], args[3], args[4], args[5],
 676                       sp, pc);
 677        unlock_trace(task);
 678
 679        return 0;
 680}
 681#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 682
 683/************************************************************************/
 684/*                       Here the fs part begins                        */
 685/************************************************************************/
 686
 687/* permission checks */
 688static int proc_fd_access_allowed(struct inode *inode)
 689{
 690        struct task_struct *task;
 691        int allowed = 0;
 692        /* Allow access to a task's file descriptors if it is us or we
 693         * may use ptrace attach to the process and find out that
 694         * information.
 695         */
 696        task = get_proc_task(inode);
 697        if (task) {
 698                allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 699                put_task_struct(task);
 700        }
 701        return allowed;
 702}
 703
 704int proc_setattr(struct dentry *dentry, struct iattr *attr)
 705{
 706        int error;
 707        struct inode *inode = d_inode(dentry);
 708
 709        if (attr->ia_valid & ATTR_MODE)
 710                return -EPERM;
 711
 712        error = inode_change_ok(inode, attr);
 713        if (error)
 714                return error;
 715
 716        setattr_copy(inode, attr);
 717        mark_inode_dirty(inode);
 718        return 0;
 719}
 720
 721/*
 722 * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 723 * or euid/egid (for hide_pid_min=2)?
 724 */
 725static bool has_pid_permissions(struct pid_namespace *pid,
 726                                 struct task_struct *task,
 727                                 int hide_pid_min)
 728{
 729        if (pid->hide_pid < hide_pid_min)
 730                return true;
 731        if (in_group_p(pid->pid_gid))
 732                return true;
 733        return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 734}
 735
 736
 737static int proc_pid_permission(struct inode *inode, int mask)
 738{
 739        struct pid_namespace *pid = inode->i_sb->s_fs_info;
 740        struct task_struct *task;
 741        bool has_perms;
 742
 743        task = get_proc_task(inode);
 744        if (!task)
 745                return -ESRCH;
 746        has_perms = has_pid_permissions(pid, task, 1);
 747        put_task_struct(task);
 748
 749        if (!has_perms) {
 750                if (pid->hide_pid == 2) {
 751                        /*
 752                         * Let's make getdents(), stat(), and open()
 753                         * consistent with each other.  If a process
 754                         * may not stat() a file, it shouldn't be seen
 755                         * in procfs at all.
 756                         */
 757                        return -ENOENT;
 758                }
 759
 760                return -EPERM;
 761        }
 762        return generic_permission(inode, mask);
 763}
 764
 765
 766
 767static const struct inode_operations proc_def_inode_operations = {
 768        .setattr        = proc_setattr,
 769};
 770
 771static int proc_single_show(struct seq_file *m, void *v)
 772{
 773        struct inode *inode = m->private;
 774        struct pid_namespace *ns;
 775        struct pid *pid;
 776        struct task_struct *task;
 777        int ret;
 778
 779        ns = inode->i_sb->s_fs_info;
 780        pid = proc_pid(inode);
 781        task = get_pid_task(pid, PIDTYPE_PID);
 782        if (!task)
 783                return -ESRCH;
 784
 785        ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 786
 787        put_task_struct(task);
 788        return ret;
 789}
 790
 791static int proc_single_open(struct inode *inode, struct file *filp)
 792{
 793        return single_open(filp, proc_single_show, inode);
 794}
 795
 796static const struct file_operations proc_single_file_operations = {
 797        .open           = proc_single_open,
 798        .read           = seq_read,
 799        .llseek         = seq_lseek,
 800        .release        = single_release,
 801};
 802
 803
 804struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 805{
 806        struct task_struct *task = get_proc_task(inode);
 807        struct mm_struct *mm = ERR_PTR(-ESRCH);
 808
 809        if (task) {
 810                mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 811                put_task_struct(task);
 812
 813                if (!IS_ERR_OR_NULL(mm)) {
 814                        /* ensure this mm_struct can't be freed */
 815                        atomic_inc(&mm->mm_count);
 816                        /* but do not pin its memory */
 817                        mmput(mm);
 818                }
 819        }
 820
 821        return mm;
 822}
 823
 824static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 825{
 826        struct mm_struct *mm = proc_mem_open(inode, mode);
 827
 828        if (IS_ERR(mm))
 829                return PTR_ERR(mm);
 830
 831        file->private_data = mm;
 832        return 0;
 833}
 834
 835static int mem_open(struct inode *inode, struct file *file)
 836{
 837        int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 838
 839        /* OK to pass negative loff_t, we can catch out-of-range */
 840        file->f_mode |= FMODE_UNSIGNED_OFFSET;
 841
 842        return ret;
 843}
 844
 845static ssize_t mem_rw(struct file *file, char __user *buf,
 846                        size_t count, loff_t *ppos, int write)
 847{
 848        struct mm_struct *mm = file->private_data;
 849        unsigned long addr = *ppos;
 850        ssize_t copied;
 851        char *page;
 852
 853        if (!mm)
 854                return 0;
 855
 856        page = (char *)__get_free_page(GFP_TEMPORARY);
 857        if (!page)
 858                return -ENOMEM;
 859
 860        copied = 0;
 861        if (!atomic_inc_not_zero(&mm->mm_users))
 862                goto free;
 863
 864        while (count > 0) {
 865                int this_len = min_t(int, count, PAGE_SIZE);
 866
 867                if (write && copy_from_user(page, buf, this_len)) {
 868                        copied = -EFAULT;
 869                        break;
 870                }
 871
 872                this_len = access_remote_vm(mm, addr, page, this_len, write);
 873                if (!this_len) {
 874                        if (!copied)
 875                                copied = -EIO;
 876                        break;
 877                }
 878
 879                if (!write && copy_to_user(buf, page, this_len)) {
 880                        copied = -EFAULT;
 881                        break;
 882                }
 883
 884                buf += this_len;
 885                addr += this_len;
 886                copied += this_len;
 887                count -= this_len;
 888        }
 889        *ppos = addr;
 890
 891        mmput(mm);
 892free:
 893        free_page((unsigned long) page);
 894        return copied;
 895}
 896
 897static ssize_t mem_read(struct file *file, char __user *buf,
 898                        size_t count, loff_t *ppos)
 899{
 900        return mem_rw(file, buf, count, ppos, 0);
 901}
 902
 903static ssize_t mem_write(struct file *file, const char __user *buf,
 904                         size_t count, loff_t *ppos)
 905{
 906        return mem_rw(file, (char __user*)buf, count, ppos, 1);
 907}
 908
 909loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 910{
 911        switch (orig) {
 912        case 0:
 913                file->f_pos = offset;
 914                break;
 915        case 1:
 916                file->f_pos += offset;
 917                break;
 918        default:
 919                return -EINVAL;
 920        }
 921        force_successful_syscall_return();
 922        return file->f_pos;
 923}
 924
 925static int mem_release(struct inode *inode, struct file *file)
 926{
 927        struct mm_struct *mm = file->private_data;
 928        if (mm)
 929                mmdrop(mm);
 930        return 0;
 931}
 932
 933static const struct file_operations proc_mem_operations = {
 934        .llseek         = mem_lseek,
 935        .read           = mem_read,
 936        .write          = mem_write,
 937        .open           = mem_open,
 938        .release        = mem_release,
 939};
 940
 941static int environ_open(struct inode *inode, struct file *file)
 942{
 943        return __mem_open(inode, file, PTRACE_MODE_READ);
 944}
 945
 946static ssize_t environ_read(struct file *file, char __user *buf,
 947                        size_t count, loff_t *ppos)
 948{
 949        char *page;
 950        unsigned long src = *ppos;
 951        int ret = 0;
 952        struct mm_struct *mm = file->private_data;
 953        unsigned long env_start, env_end;
 954
 955        /* Ensure the process spawned far enough to have an environment. */
 956        if (!mm || !mm->env_end)
 957                return 0;
 958
 959        page = (char *)__get_free_page(GFP_TEMPORARY);
 960        if (!page)
 961                return -ENOMEM;
 962
 963        ret = 0;
 964        if (!atomic_inc_not_zero(&mm->mm_users))
 965                goto free;
 966
 967        down_read(&mm->mmap_sem);
 968        env_start = mm->env_start;
 969        env_end = mm->env_end;
 970        up_read(&mm->mmap_sem);
 971
 972        while (count > 0) {
 973                size_t this_len, max_len;
 974                int retval;
 975
 976                if (src >= (env_end - env_start))
 977                        break;
 978
 979                this_len = env_end - (env_start + src);
 980
 981                max_len = min_t(size_t, PAGE_SIZE, count);
 982                this_len = min(max_len, this_len);
 983
 984                retval = access_remote_vm(mm, (env_start + src),
 985                        page, this_len, 0);
 986
 987                if (retval <= 0) {
 988                        ret = retval;
 989                        break;
 990                }
 991
 992                if (copy_to_user(buf, page, retval)) {
 993                        ret = -EFAULT;
 994                        break;
 995                }
 996
 997                ret += retval;
 998                src += retval;
 999                buf += retval;
1000                count -= retval;
1001        }
1002        *ppos = src;
1003        mmput(mm);
1004
1005free:
1006        free_page((unsigned long) page);
1007        return ret;
1008}
1009
1010static const struct file_operations proc_environ_operations = {
1011        .open           = environ_open,
1012        .read           = environ_read,
1013        .llseek         = generic_file_llseek,
1014        .release        = mem_release,
1015};
1016
1017static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1018                            loff_t *ppos)
1019{
1020        struct task_struct *task = get_proc_task(file_inode(file));
1021        char buffer[PROC_NUMBUF];
1022        int oom_adj = OOM_ADJUST_MIN;
1023        size_t len;
1024
1025        if (!task)
1026                return -ESRCH;
1027        if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1028                oom_adj = OOM_ADJUST_MAX;
1029        else
1030                oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1031                          OOM_SCORE_ADJ_MAX;
1032        put_task_struct(task);
1033        len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1034        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1035}
1036
1037static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1038{
1039        static DEFINE_MUTEX(oom_adj_mutex);
1040        struct mm_struct *mm = NULL;
1041        struct task_struct *task;
1042        int err = 0;
1043
1044        task = get_proc_task(file_inode(file));
1045        if (!task)
1046                return -ESRCH;
1047
1048        mutex_lock(&oom_adj_mutex);
1049        if (legacy) {
1050                if (oom_adj < task->signal->oom_score_adj &&
1051                                !capable(CAP_SYS_RESOURCE)) {
1052                        err = -EACCES;
1053                        goto err_unlock;
1054                }
1055                /*
1056                 * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1057                 * /proc/pid/oom_score_adj instead.
1058                 */
1059                pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1060                          current->comm, task_pid_nr(current), task_pid_nr(task),
1061                          task_pid_nr(task));
1062        } else {
1063                if ((short)oom_adj < task->signal->oom_score_adj_min &&
1064                                !capable(CAP_SYS_RESOURCE)) {
1065                        err = -EACCES;
1066                        goto err_unlock;
1067                }
1068        }
1069
1070        /*
1071         * Make sure we will check other processes sharing the mm if this is
1072         * not vfrok which wants its own oom_score_adj.
1073         * pin the mm so it doesn't go away and get reused after task_unlock
1074         */
1075        if (!task->vfork_done) {
1076                struct task_struct *p = find_lock_task_mm(task);
1077
1078                if (p) {
1079                        if (atomic_read(&p->mm->mm_users) > 1) {
1080                                mm = p->mm;
1081                                atomic_inc(&mm->mm_count);
1082                        }
1083                        task_unlock(p);
1084                }
1085        }
1086
1087        task->signal->oom_score_adj = oom_adj;
1088        if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1089                task->signal->oom_score_adj_min = (short)oom_adj;
1090        trace_oom_score_adj_update(task);
1091
1092        if (mm) {
1093                struct task_struct *p;
1094
1095                rcu_read_lock();
1096                for_each_process(p) {
1097                        if (same_thread_group(task, p))
1098                                continue;
1099
1100                        /* do not touch kernel threads or the global init */
1101                        if (p->flags & PF_KTHREAD || is_global_init(p))
1102                                continue;
1103
1104                        task_lock(p);
1105                        if (!p->vfork_done && process_shares_mm(p, mm)) {
1106                                pr_info("updating oom_score_adj for %d (%s) from %d to %d because it shares mm with %d (%s). Report if this is unexpected.\n",
1107                                                task_pid_nr(p), p->comm,
1108                                                p->signal->oom_score_adj, oom_adj,
1109                                                task_pid_nr(task), task->comm);
1110                                p->signal->oom_score_adj = oom_adj;
1111                                if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1112                                        p->signal->oom_score_adj_min = (short)oom_adj;
1113                        }
1114                        task_unlock(p);
1115                }
1116                rcu_read_unlock();
1117                mmdrop(mm);
1118        }
1119err_unlock:
1120        mutex_unlock(&oom_adj_mutex);
1121        put_task_struct(task);
1122        return err;
1123}
1124
1125/*
1126 * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1127 * kernels.  The effective policy is defined by oom_score_adj, which has a
1128 * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1129 * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1130 * Processes that become oom disabled via oom_adj will still be oom disabled
1131 * with this implementation.
1132 *
1133 * oom_adj cannot be removed since existing userspace binaries use it.
1134 */
1135static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1136                             size_t count, loff_t *ppos)
1137{
1138        char buffer[PROC_NUMBUF];
1139        int oom_adj;
1140        int err;
1141
1142        memset(buffer, 0, sizeof(buffer));
1143        if (count > sizeof(buffer) - 1)
1144                count = sizeof(buffer) - 1;
1145        if (copy_from_user(buffer, buf, count)) {
1146                err = -EFAULT;
1147                goto out;
1148        }
1149
1150        err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1151        if (err)
1152                goto out;
1153        if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1154             oom_adj != OOM_DISABLE) {
1155                err = -EINVAL;
1156                goto out;
1157        }
1158
1159        /*
1160         * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1161         * value is always attainable.
1162         */
1163        if (oom_adj == OOM_ADJUST_MAX)
1164                oom_adj = OOM_SCORE_ADJ_MAX;
1165        else
1166                oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1167
1168        err = __set_oom_adj(file, oom_adj, true);
1169out:
1170        return err < 0 ? err : count;
1171}
1172
1173static const struct file_operations proc_oom_adj_operations = {
1174        .read           = oom_adj_read,
1175        .write          = oom_adj_write,
1176        .llseek         = generic_file_llseek,
1177};
1178
1179static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1180                                        size_t count, loff_t *ppos)
1181{
1182        struct task_struct *task = get_proc_task(file_inode(file));
1183        char buffer[PROC_NUMBUF];
1184        short oom_score_adj = OOM_SCORE_ADJ_MIN;
1185        size_t len;
1186
1187        if (!task)
1188                return -ESRCH;
1189        oom_score_adj = task->signal->oom_score_adj;
1190        put_task_struct(task);
1191        len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1192        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1193}
1194
1195static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1196                                        size_t count, loff_t *ppos)
1197{
1198        char buffer[PROC_NUMBUF];
1199        int oom_score_adj;
1200        int err;
1201
1202        memset(buffer, 0, sizeof(buffer));
1203        if (count > sizeof(buffer) - 1)
1204                count = sizeof(buffer) - 1;
1205        if (copy_from_user(buffer, buf, count)) {
1206                err = -EFAULT;
1207                goto out;
1208        }
1209
1210        err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1211        if (err)
1212                goto out;
1213        if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1214                        oom_score_adj > OOM_SCORE_ADJ_MAX) {
1215                err = -EINVAL;
1216                goto out;
1217        }
1218
1219        err = __set_oom_adj(file, oom_score_adj, false);
1220out:
1221        return err < 0 ? err : count;
1222}
1223
1224static const struct file_operations proc_oom_score_adj_operations = {
1225        .read           = oom_score_adj_read,
1226        .write          = oom_score_adj_write,
1227        .llseek         = default_llseek,
1228};
1229
1230#ifdef CONFIG_AUDITSYSCALL
1231#define TMPBUFLEN 21
1232static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1233                                  size_t count, loff_t *ppos)
1234{
1235        struct inode * inode = file_inode(file);
1236        struct task_struct *task = get_proc_task(inode);
1237        ssize_t length;
1238        char tmpbuf[TMPBUFLEN];
1239
1240        if (!task)
1241                return -ESRCH;
1242        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1243                           from_kuid(file->f_cred->user_ns,
1244                                     audit_get_loginuid(task)));
1245        put_task_struct(task);
1246        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1247}
1248
1249static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1250                                   size_t count, loff_t *ppos)
1251{
1252        struct inode * inode = file_inode(file);
1253        uid_t loginuid;
1254        kuid_t kloginuid;
1255        int rv;
1256
1257        rcu_read_lock();
1258        if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1259                rcu_read_unlock();
1260                return -EPERM;
1261        }
1262        rcu_read_unlock();
1263
1264        if (*ppos != 0) {
1265                /* No partial writes. */
1266                return -EINVAL;
1267        }
1268
1269        rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1270        if (rv < 0)
1271                return rv;
1272
1273        /* is userspace tring to explicitly UNSET the loginuid? */
1274        if (loginuid == AUDIT_UID_UNSET) {
1275                kloginuid = INVALID_UID;
1276        } else {
1277                kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1278                if (!uid_valid(kloginuid))
1279                        return -EINVAL;
1280        }
1281
1282        rv = audit_set_loginuid(kloginuid);
1283        if (rv < 0)
1284                return rv;
1285        return count;
1286}
1287
1288static const struct file_operations proc_loginuid_operations = {
1289        .read           = proc_loginuid_read,
1290        .write          = proc_loginuid_write,
1291        .llseek         = generic_file_llseek,
1292};
1293
1294static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1295                                  size_t count, loff_t *ppos)
1296{
1297        struct inode * inode = file_inode(file);
1298        struct task_struct *task = get_proc_task(inode);
1299        ssize_t length;
1300        char tmpbuf[TMPBUFLEN];
1301
1302        if (!task)
1303                return -ESRCH;
1304        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1305                                audit_get_sessionid(task));
1306        put_task_struct(task);
1307        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1308}
1309
1310static const struct file_operations proc_sessionid_operations = {
1311        .read           = proc_sessionid_read,
1312        .llseek         = generic_file_llseek,
1313};
1314#endif
1315
1316#ifdef CONFIG_FAULT_INJECTION
1317static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1318                                      size_t count, loff_t *ppos)
1319{
1320        struct task_struct *task = get_proc_task(file_inode(file));
1321        char buffer[PROC_NUMBUF];
1322        size_t len;
1323        int make_it_fail;
1324
1325        if (!task)
1326                return -ESRCH;
1327        make_it_fail = task->make_it_fail;
1328        put_task_struct(task);
1329
1330        len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1331
1332        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1333}
1334
1335static ssize_t proc_fault_inject_write(struct file * file,
1336                        const char __user * buf, size_t count, loff_t *ppos)
1337{
1338        struct task_struct *task;
1339        char buffer[PROC_NUMBUF];
1340        int make_it_fail;
1341        int rv;
1342
1343        if (!capable(CAP_SYS_RESOURCE))
1344                return -EPERM;
1345        memset(buffer, 0, sizeof(buffer));
1346        if (count > sizeof(buffer) - 1)
1347                count = sizeof(buffer) - 1;
1348        if (copy_from_user(buffer, buf, count))
1349                return -EFAULT;
1350        rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1351        if (rv < 0)
1352                return rv;
1353        if (make_it_fail < 0 || make_it_fail > 1)
1354                return -EINVAL;
1355
1356        task = get_proc_task(file_inode(file));
1357        if (!task)
1358                return -ESRCH;
1359        task->make_it_fail = make_it_fail;
1360        put_task_struct(task);
1361
1362        return count;
1363}
1364
1365static const struct file_operations proc_fault_inject_operations = {
1366        .read           = proc_fault_inject_read,
1367        .write          = proc_fault_inject_write,
1368        .llseek         = generic_file_llseek,
1369};
1370#endif
1371
1372
1373#ifdef CONFIG_SCHED_DEBUG
1374/*
1375 * Print out various scheduling related per-task fields:
1376 */
1377static int sched_show(struct seq_file *m, void *v)
1378{
1379        struct inode *inode = m->private;
1380        struct task_struct *p;
1381
1382        p = get_proc_task(inode);
1383        if (!p)
1384                return -ESRCH;
1385        proc_sched_show_task(p, m);
1386
1387        put_task_struct(p);
1388
1389        return 0;
1390}
1391
1392static ssize_t
1393sched_write(struct file *file, const char __user *buf,
1394            size_t count, loff_t *offset)
1395{
1396        struct inode *inode = file_inode(file);
1397        struct task_struct *p;
1398
1399        p = get_proc_task(inode);
1400        if (!p)
1401                return -ESRCH;
1402        proc_sched_set_task(p);
1403
1404        put_task_struct(p);
1405
1406        return count;
1407}
1408
1409static int sched_open(struct inode *inode, struct file *filp)
1410{
1411        return single_open(filp, sched_show, inode);
1412}
1413
1414static const struct file_operations proc_pid_sched_operations = {
1415        .open           = sched_open,
1416        .read           = seq_read,
1417        .write          = sched_write,
1418        .llseek         = seq_lseek,
1419        .release        = single_release,
1420};
1421
1422#endif
1423
1424#ifdef CONFIG_SCHED_AUTOGROUP
1425/*
1426 * Print out autogroup related information:
1427 */
1428static int sched_autogroup_show(struct seq_file *m, void *v)
1429{
1430        struct inode *inode = m->private;
1431        struct task_struct *p;
1432
1433        p = get_proc_task(inode);
1434        if (!p)
1435                return -ESRCH;
1436        proc_sched_autogroup_show_task(p, m);
1437
1438        put_task_struct(p);
1439
1440        return 0;
1441}
1442
1443static ssize_t
1444sched_autogroup_write(struct file *file, const char __user *buf,
1445            size_t count, loff_t *offset)
1446{
1447        struct inode *inode = file_inode(file);
1448        struct task_struct *p;
1449        char buffer[PROC_NUMBUF];
1450        int nice;
1451        int err;
1452
1453        memset(buffer, 0, sizeof(buffer));
1454        if (count > sizeof(buffer) - 1)
1455                count = sizeof(buffer) - 1;
1456        if (copy_from_user(buffer, buf, count))
1457                return -EFAULT;
1458
1459        err = kstrtoint(strstrip(buffer), 0, &nice);
1460        if (err < 0)
1461                return err;
1462
1463        p = get_proc_task(inode);
1464        if (!p)
1465                return -ESRCH;
1466
1467        err = proc_sched_autogroup_set_nice(p, nice);
1468        if (err)
1469                count = err;
1470
1471        put_task_struct(p);
1472
1473        return count;
1474}
1475
1476static int sched_autogroup_open(struct inode *inode, struct file *filp)
1477{
1478        int ret;
1479
1480        ret = single_open(filp, sched_autogroup_show, NULL);
1481        if (!ret) {
1482                struct seq_file *m = filp->private_data;
1483
1484                m->private = inode;
1485        }
1486        return ret;
1487}
1488
1489static const struct file_operations proc_pid_sched_autogroup_operations = {
1490        .open           = sched_autogroup_open,
1491        .read           = seq_read,
1492        .write          = sched_autogroup_write,
1493        .llseek         = seq_lseek,
1494        .release        = single_release,
1495};
1496
1497#endif /* CONFIG_SCHED_AUTOGROUP */
1498
1499static ssize_t comm_write(struct file *file, const char __user *buf,
1500                                size_t count, loff_t *offset)
1501{
1502        struct inode *inode = file_inode(file);
1503        struct task_struct *p;
1504        char buffer[TASK_COMM_LEN];
1505        const size_t maxlen = sizeof(buffer) - 1;
1506
1507        memset(buffer, 0, sizeof(buffer));
1508        if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1509                return -EFAULT;
1510
1511        p = get_proc_task(inode);
1512        if (!p)
1513                return -ESRCH;
1514
1515        if (same_thread_group(current, p))
1516                set_task_comm(p, buffer);
1517        else
1518                count = -EINVAL;
1519
1520        put_task_struct(p);
1521
1522        return count;
1523}
1524
1525static int comm_show(struct seq_file *m, void *v)
1526{
1527        struct inode *inode = m->private;
1528        struct task_struct *p;
1529
1530        p = get_proc_task(inode);
1531        if (!p)
1532                return -ESRCH;
1533
1534        task_lock(p);
1535        seq_printf(m, "%s\n", p->comm);
1536        task_unlock(p);
1537
1538        put_task_struct(p);
1539
1540        return 0;
1541}
1542
1543static int comm_open(struct inode *inode, struct file *filp)
1544{
1545        return single_open(filp, comm_show, inode);
1546}
1547
1548static const struct file_operations proc_pid_set_comm_operations = {
1549        .open           = comm_open,
1550        .read           = seq_read,
1551        .write          = comm_write,
1552        .llseek         = seq_lseek,
1553        .release        = single_release,
1554};
1555
1556static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1557{
1558        struct task_struct *task;
1559        struct file *exe_file;
1560
1561        task = get_proc_task(d_inode(dentry));
1562        if (!task)
1563                return -ENOENT;
1564        exe_file = get_task_exe_file(task);
1565        put_task_struct(task);
1566        if (exe_file) {
1567                *exe_path = exe_file->f_path;
1568                path_get(&exe_file->f_path);
1569                fput(exe_file);
1570                return 0;
1571        } else
1572                return -ENOENT;
1573}
1574
1575static const char *proc_pid_get_link(struct dentry *dentry,
1576                                     struct inode *inode,
1577                                     struct delayed_call *done)
1578{
1579        struct path path;
1580        int error = -EACCES;
1581
1582        if (!dentry)
1583                return ERR_PTR(-ECHILD);
1584
1585        /* Are we allowed to snoop on the tasks file descriptors? */
1586        if (!proc_fd_access_allowed(inode))
1587                goto out;
1588
1589        error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1590        if (error)
1591                goto out;
1592
1593        nd_jump_link(&path);
1594        return NULL;
1595out:
1596        return ERR_PTR(error);
1597}
1598
1599static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1600{
1601        char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1602        char *pathname;
1603        int len;
1604
1605        if (!tmp)
1606                return -ENOMEM;
1607
1608        pathname = d_path(path, tmp, PAGE_SIZE);
1609        len = PTR_ERR(pathname);
1610        if (IS_ERR(pathname))
1611                goto out;
1612        len = tmp + PAGE_SIZE - 1 - pathname;
1613
1614        if (len > buflen)
1615                len = buflen;
1616        if (copy_to_user(buffer, pathname, len))
1617                len = -EFAULT;
1618 out:
1619        free_page((unsigned long)tmp);
1620        return len;
1621}
1622
1623static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1624{
1625        int error = -EACCES;
1626        struct inode *inode = d_inode(dentry);
1627        struct path path;
1628
1629        /* Are we allowed to snoop on the tasks file descriptors? */
1630        if (!proc_fd_access_allowed(inode))
1631                goto out;
1632
1633        error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1634        if (error)
1635                goto out;
1636
1637        error = do_proc_readlink(&path, buffer, buflen);
1638        path_put(&path);
1639out:
1640        return error;
1641}
1642
1643const struct inode_operations proc_pid_link_inode_operations = {
1644        .readlink       = proc_pid_readlink,
1645        .get_link       = proc_pid_get_link,
1646        .setattr        = proc_setattr,
1647};
1648
1649
1650/* building an inode */
1651
1652struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1653{
1654        struct inode * inode;
1655        struct proc_inode *ei;
1656        const struct cred *cred;
1657
1658        /* We need a new inode */
1659
1660        inode = new_inode(sb);
1661        if (!inode)
1662                goto out;
1663
1664        /* Common stuff */
1665        ei = PROC_I(inode);
1666        inode->i_ino = get_next_ino();
1667        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1668        inode->i_op = &proc_def_inode_operations;
1669
1670        /*
1671         * grab the reference to task.
1672         */
1673        ei->pid = get_task_pid(task, PIDTYPE_PID);
1674        if (!ei->pid)
1675                goto out_unlock;
1676
1677        if (task_dumpable(task)) {
1678                rcu_read_lock();
1679                cred = __task_cred(task);
1680                inode->i_uid = cred->euid;
1681                inode->i_gid = cred->egid;
1682                rcu_read_unlock();
1683        }
1684        security_task_to_inode(task, inode);
1685
1686out:
1687        return inode;
1688
1689out_unlock:
1690        iput(inode);
1691        return NULL;
1692}
1693
1694int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1695{
1696        struct inode *inode = d_inode(dentry);
1697        struct task_struct *task;
1698        const struct cred *cred;
1699        struct pid_namespace *pid = dentry->d_sb->s_fs_info;
1700
1701        generic_fillattr(inode, stat);
1702
1703        rcu_read_lock();
1704        stat->uid = GLOBAL_ROOT_UID;
1705        stat->gid = GLOBAL_ROOT_GID;
1706        task = pid_task(proc_pid(inode), PIDTYPE_PID);
1707        if (task) {
1708                if (!has_pid_permissions(pid, task, 2)) {
1709                        rcu_read_unlock();
1710                        /*
1711                         * This doesn't prevent learning whether PID exists,
1712                         * it only makes getattr() consistent with readdir().
1713                         */
1714                        return -ENOENT;
1715                }
1716                if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1717                    task_dumpable(task)) {
1718                        cred = __task_cred(task);
1719                        stat->uid = cred->euid;
1720                        stat->gid = cred->egid;
1721                }
1722        }
1723        rcu_read_unlock();
1724        return 0;
1725}
1726
1727/* dentry stuff */
1728
1729/*
1730 *      Exceptional case: normally we are not allowed to unhash a busy
1731 * directory. In this case, however, we can do it - no aliasing problems
1732 * due to the way we treat inodes.
1733 *
1734 * Rewrite the inode's ownerships here because the owning task may have
1735 * performed a setuid(), etc.
1736 *
1737 * Before the /proc/pid/status file was created the only way to read
1738 * the effective uid of a /process was to stat /proc/pid.  Reading
1739 * /proc/pid/status is slow enough that procps and other packages
1740 * kept stating /proc/pid.  To keep the rules in /proc simple I have
1741 * made this apply to all per process world readable and executable
1742 * directories.
1743 */
1744int pid_revalidate(struct dentry *dentry, unsigned int flags)
1745{
1746        struct inode *inode;
1747        struct task_struct *task;
1748        const struct cred *cred;
1749
1750        if (flags & LOOKUP_RCU)
1751                return -ECHILD;
1752
1753        inode = d_inode(dentry);
1754        task = get_proc_task(inode);
1755
1756        if (task) {
1757                if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1758                    task_dumpable(task)) {
1759                        rcu_read_lock();
1760                        cred = __task_cred(task);
1761                        inode->i_uid = cred->euid;
1762                        inode->i_gid = cred->egid;
1763                        rcu_read_unlock();
1764                } else {
1765                        inode->i_uid = GLOBAL_ROOT_UID;
1766                        inode->i_gid = GLOBAL_ROOT_GID;
1767                }
1768                inode->i_mode &= ~(S_ISUID | S_ISGID);
1769                security_task_to_inode(task, inode);
1770                put_task_struct(task);
1771                return 1;
1772        }
1773        return 0;
1774}
1775
1776static inline bool proc_inode_is_dead(struct inode *inode)
1777{
1778        return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1779}
1780
1781int pid_delete_dentry(const struct dentry *dentry)
1782{
1783        /* Is the task we represent dead?
1784         * If so, then don't put the dentry on the lru list,
1785         * kill it immediately.
1786         */
1787        return proc_inode_is_dead(d_inode(dentry));
1788}
1789
1790const struct dentry_operations pid_dentry_operations =
1791{
1792        .d_revalidate   = pid_revalidate,
1793        .d_delete       = pid_delete_dentry,
1794};
1795
1796/* Lookups */
1797
1798/*
1799 * Fill a directory entry.
1800 *
1801 * If possible create the dcache entry and derive our inode number and
1802 * file type from dcache entry.
1803 *
1804 * Since all of the proc inode numbers are dynamically generated, the inode
1805 * numbers do not exist until the inode is cache.  This means creating the
1806 * the dcache entry in readdir is necessary to keep the inode numbers
1807 * reported by readdir in sync with the inode numbers reported
1808 * by stat.
1809 */
1810bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1811        const char *name, int len,
1812        instantiate_t instantiate, struct task_struct *task, const void *ptr)
1813{
1814        struct dentry *child, *dir = file->f_path.dentry;
1815        struct qstr qname = QSTR_INIT(name, len);
1816        struct inode *inode;
1817        unsigned type;
1818        ino_t ino;
1819
1820        child = d_hash_and_lookup(dir, &qname);
1821        if (!child) {
1822                DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1823                child = d_alloc_parallel(dir, &qname, &wq);
1824                if (IS_ERR(child))
1825                        goto end_instantiate;
1826                if (d_in_lookup(child)) {
1827                        int err = instantiate(d_inode(dir), child, task, ptr);
1828                        d_lookup_done(child);
1829                        if (err < 0) {
1830                                dput(child);
1831                                goto end_instantiate;
1832                        }
1833                }
1834        }
1835        inode = d_inode(child);
1836        ino = inode->i_ino;
1837        type = inode->i_mode >> 12;
1838        dput(child);
1839        return dir_emit(ctx, name, len, ino, type);
1840
1841end_instantiate:
1842        return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
1843}
1844
1845/*
1846 * dname_to_vma_addr - maps a dentry name into two unsigned longs
1847 * which represent vma start and end addresses.
1848 */
1849static int dname_to_vma_addr(struct dentry *dentry,
1850                             unsigned long *start, unsigned long *end)
1851{
1852        if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
1853                return -EINVAL;
1854
1855        return 0;
1856}
1857
1858static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1859{
1860        unsigned long vm_start, vm_end;
1861        bool exact_vma_exists = false;
1862        struct mm_struct *mm = NULL;
1863        struct task_struct *task;
1864        const struct cred *cred;
1865        struct inode *inode;
1866        int status = 0;
1867
1868        if (flags & LOOKUP_RCU)
1869                return -ECHILD;
1870
1871        inode = d_inode(dentry);
1872        task = get_proc_task(inode);
1873        if (!task)
1874                goto out_notask;
1875
1876        mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1877        if (IS_ERR_OR_NULL(mm))
1878                goto out;
1879
1880        if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1881                down_read(&mm->mmap_sem);
1882                exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1883                up_read(&mm->mmap_sem);
1884        }
1885
1886        mmput(mm);
1887
1888        if (exact_vma_exists) {
1889                if (task_dumpable(task)) {
1890                        rcu_read_lock();
1891                        cred = __task_cred(task);
1892                        inode->i_uid = cred->euid;
1893                        inode->i_gid = cred->egid;
1894                        rcu_read_unlock();
1895                } else {
1896                        inode->i_uid = GLOBAL_ROOT_UID;
1897                        inode->i_gid = GLOBAL_ROOT_GID;
1898                }
1899                security_task_to_inode(task, inode);
1900                status = 1;
1901        }
1902
1903out:
1904        put_task_struct(task);
1905
1906out_notask:
1907        return status;
1908}
1909
1910static const struct dentry_operations tid_map_files_dentry_operations = {
1911        .d_revalidate   = map_files_d_revalidate,
1912        .d_delete       = pid_delete_dentry,
1913};
1914
1915static int map_files_get_link(struct dentry *dentry, struct path *path)
1916{
1917        unsigned long vm_start, vm_end;
1918        struct vm_area_struct *vma;
1919        struct task_struct *task;
1920        struct mm_struct *mm;
1921        int rc;
1922
1923        rc = -ENOENT;
1924        task = get_proc_task(d_inode(dentry));
1925        if (!task)
1926                goto out;
1927
1928        mm = get_task_mm(task);
1929        put_task_struct(task);
1930        if (!mm)
1931                goto out;
1932
1933        rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
1934        if (rc)
1935                goto out_mmput;
1936
1937        rc = -ENOENT;
1938        down_read(&mm->mmap_sem);
1939        vma = find_exact_vma(mm, vm_start, vm_end);
1940        if (vma && vma->vm_file) {
1941                *path = vma->vm_file->f_path;
1942                path_get(path);
1943                rc = 0;
1944        }
1945        up_read(&mm->mmap_sem);
1946
1947out_mmput:
1948        mmput(mm);
1949out:
1950        return rc;
1951}
1952
1953struct map_files_info {
1954        fmode_t         mode;
1955        unsigned long   len;
1956        unsigned char   name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
1957};
1958
1959/*
1960 * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
1961 * symlinks may be used to bypass permissions on ancestor directories in the
1962 * path to the file in question.
1963 */
1964static const char *
1965proc_map_files_get_link(struct dentry *dentry,
1966                        struct inode *inode,
1967                        struct delayed_call *done)
1968{
1969        if (!capable(CAP_SYS_ADMIN))
1970                return ERR_PTR(-EPERM);
1971
1972        return proc_pid_get_link(dentry, inode, done);
1973}
1974
1975/*
1976 * Identical to proc_pid_link_inode_operations except for get_link()
1977 */
1978static const struct inode_operations proc_map_files_link_inode_operations = {
1979        .readlink       = proc_pid_readlink,
1980        .get_link       = proc_map_files_get_link,
1981        .setattr        = proc_setattr,
1982};
1983
1984static int
1985proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
1986                           struct task_struct *task, const void *ptr)
1987{
1988        fmode_t mode = (fmode_t)(unsigned long)ptr;
1989        struct proc_inode *ei;
1990        struct inode *inode;
1991
1992        inode = proc_pid_make_inode(dir->i_sb, task);
1993        if (!inode)
1994                return -ENOENT;
1995
1996        ei = PROC_I(inode);
1997        ei->op.proc_get_link = map_files_get_link;
1998
1999        inode->i_op = &proc_map_files_link_inode_operations;
2000        inode->i_size = 64;
2001        inode->i_mode = S_IFLNK;
2002
2003        if (mode & FMODE_READ)
2004                inode->i_mode |= S_IRUSR;
2005        if (mode & FMODE_WRITE)
2006                inode->i_mode |= S_IWUSR;
2007
2008        d_set_d_op(dentry, &tid_map_files_dentry_operations);
2009        d_add(dentry, inode);
2010
2011        return 0;
2012}
2013
2014static struct dentry *proc_map_files_lookup(struct inode *dir,
2015                struct dentry *dentry, unsigned int flags)
2016{
2017        unsigned long vm_start, vm_end;
2018        struct vm_area_struct *vma;
2019        struct task_struct *task;
2020        int result;
2021        struct mm_struct *mm;
2022
2023        result = -ENOENT;
2024        task = get_proc_task(dir);
2025        if (!task)
2026                goto out;
2027
2028        result = -EACCES;
2029        if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2030                goto out_put_task;
2031
2032        result = -ENOENT;
2033        if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2034                goto out_put_task;
2035
2036        mm = get_task_mm(task);
2037        if (!mm)
2038                goto out_put_task;
2039
2040        down_read(&mm->mmap_sem);
2041        vma = find_exact_vma(mm, vm_start, vm_end);
2042        if (!vma)
2043                goto out_no_vma;
2044
2045        if (vma->vm_file)
2046                result = proc_map_files_instantiate(dir, dentry, task,
2047                                (void *)(unsigned long)vma->vm_file->f_mode);
2048
2049out_no_vma:
2050        up_read(&mm->mmap_sem);
2051        mmput(mm);
2052out_put_task:
2053        put_task_struct(task);
2054out:
2055        return ERR_PTR(result);
2056}
2057
2058static const struct inode_operations proc_map_files_inode_operations = {
2059        .lookup         = proc_map_files_lookup,
2060        .permission     = proc_fd_permission,
2061        .setattr        = proc_setattr,
2062};
2063
2064static int
2065proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2066{
2067        struct vm_area_struct *vma;
2068        struct task_struct *task;
2069        struct mm_struct *mm;
2070        unsigned long nr_files, pos, i;
2071        struct flex_array *fa = NULL;
2072        struct map_files_info info;
2073        struct map_files_info *p;
2074        int ret;
2075
2076        ret = -ENOENT;
2077        task = get_proc_task(file_inode(file));
2078        if (!task)
2079                goto out;
2080
2081        ret = -EACCES;
2082        if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2083                goto out_put_task;
2084
2085        ret = 0;
2086        if (!dir_emit_dots(file, ctx))
2087                goto out_put_task;
2088
2089        mm = get_task_mm(task);
2090        if (!mm)
2091                goto out_put_task;
2092        down_read(&mm->mmap_sem);
2093
2094        nr_files = 0;
2095
2096        /*
2097         * We need two passes here:
2098         *
2099         *  1) Collect vmas of mapped files with mmap_sem taken
2100         *  2) Release mmap_sem and instantiate entries
2101         *
2102         * otherwise we get lockdep complained, since filldir()
2103         * routine might require mmap_sem taken in might_fault().
2104         */
2105
2106        for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2107                if (vma->vm_file && ++pos > ctx->pos)
2108                        nr_files++;
2109        }
2110
2111        if (nr_files) {
2112                fa = flex_array_alloc(sizeof(info), nr_files,
2113                                        GFP_KERNEL);
2114                if (!fa || flex_array_prealloc(fa, 0, nr_files,
2115                                                GFP_KERNEL)) {
2116                        ret = -ENOMEM;
2117                        if (fa)
2118                                flex_array_free(fa);
2119                        up_read(&mm->mmap_sem);
2120                        mmput(mm);
2121                        goto out_put_task;
2122                }
2123                for (i = 0, vma = mm->mmap, pos = 2; vma;
2124                                vma = vma->vm_next) {
2125                        if (!vma->vm_file)
2126                                continue;
2127                        if (++pos <= ctx->pos)
2128                                continue;
2129
2130                        info.mode = vma->vm_file->f_mode;
2131                        info.len = snprintf(info.name,
2132                                        sizeof(info.name), "%lx-%lx",
2133                                        vma->vm_start, vma->vm_end);
2134                        if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2135                                BUG();
2136                }
2137        }
2138        up_read(&mm->mmap_sem);
2139
2140        for (i = 0; i < nr_files; i++) {
2141                p = flex_array_get(fa, i);
2142                if (!proc_fill_cache(file, ctx,
2143                                      p->name, p->len,
2144                                      proc_map_files_instantiate,
2145                                      task,
2146                                      (void *)(unsigned long)p->mode))
2147                        break;
2148                ctx->pos++;
2149        }
2150        if (fa)
2151                flex_array_free(fa);
2152        mmput(mm);
2153
2154out_put_task:
2155        put_task_struct(task);
2156out:
2157        return ret;
2158}
2159
2160static const struct file_operations proc_map_files_operations = {
2161        .read           = generic_read_dir,
2162        .iterate_shared = proc_map_files_readdir,
2163        .llseek         = generic_file_llseek,
2164};
2165
2166#ifdef CONFIG_CHECKPOINT_RESTORE
2167struct timers_private {
2168        struct pid *pid;
2169        struct task_struct *task;
2170        struct sighand_struct *sighand;
2171        struct pid_namespace *ns;
2172        unsigned long flags;
2173};
2174
2175static void *timers_start(struct seq_file *m, loff_t *pos)
2176{
2177        struct timers_private *tp = m->private;
2178
2179        tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2180        if (!tp->task)
2181                return ERR_PTR(-ESRCH);
2182
2183        tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2184        if (!tp->sighand)
2185                return ERR_PTR(-ESRCH);
2186
2187        return seq_list_start(&tp->task->signal->posix_timers, *pos);
2188}
2189
2190static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2191{
2192        struct timers_private *tp = m->private;
2193        return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2194}
2195
2196static void timers_stop(struct seq_file *m, void *v)
2197{
2198        struct timers_private *tp = m->private;
2199
2200        if (tp->sighand) {
2201                unlock_task_sighand(tp->task, &tp->flags);
2202                tp->sighand = NULL;
2203        }
2204
2205        if (tp->task) {
2206                put_task_struct(tp->task);
2207                tp->task = NULL;
2208        }
2209}
2210
2211static int show_timer(struct seq_file *m, void *v)
2212{
2213        struct k_itimer *timer;
2214        struct timers_private *tp = m->private;
2215        int notify;
2216        static const char * const nstr[] = {
2217                [SIGEV_SIGNAL] = "signal",
2218                [SIGEV_NONE] = "none",
2219                [SIGEV_THREAD] = "thread",
2220        };
2221
2222        timer = list_entry((struct list_head *)v, struct k_itimer, list);
2223        notify = timer->it_sigev_notify;
2224
2225        seq_printf(m, "ID: %d\n", timer->it_id);
2226        seq_printf(m, "signal: %d/%p\n",
2227                   timer->sigq->info.si_signo,
2228                   timer->sigq->info.si_value.sival_ptr);
2229        seq_printf(m, "notify: %s/%s.%d\n",
2230                   nstr[notify & ~SIGEV_THREAD_ID],
2231                   (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2232                   pid_nr_ns(timer->it_pid, tp->ns));
2233        seq_printf(m, "ClockID: %d\n", timer->it_clock);
2234
2235        return 0;
2236}
2237
2238static const struct seq_operations proc_timers_seq_ops = {
2239        .start  = timers_start,
2240        .next   = timers_next,
2241        .stop   = timers_stop,
2242        .show   = show_timer,
2243};
2244
2245static int proc_timers_open(struct inode *inode, struct file *file)
2246{
2247        struct timers_private *tp;
2248
2249        tp = __seq_open_private(file, &proc_timers_seq_ops,
2250                        sizeof(struct timers_private));
2251        if (!tp)
2252                return -ENOMEM;
2253
2254        tp->pid = proc_pid(inode);
2255        tp->ns = inode->i_sb->s_fs_info;
2256        return 0;
2257}
2258
2259static const struct file_operations proc_timers_operations = {
2260        .open           = proc_timers_open,
2261        .read           = seq_read,
2262        .llseek         = seq_lseek,
2263        .release        = seq_release_private,
2264};
2265#endif
2266
2267static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2268                                        size_t count, loff_t *offset)
2269{
2270        struct inode *inode = file_inode(file);
2271        struct task_struct *p;
2272        u64 slack_ns;
2273        int err;
2274
2275        err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2276        if (err < 0)
2277                return err;
2278
2279        p = get_proc_task(inode);
2280        if (!p)
2281                return -ESRCH;
2282
2283        if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) {
2284                task_lock(p);
2285                if (slack_ns == 0)
2286                        p->timer_slack_ns = p->default_timer_slack_ns;
2287                else
2288                        p->timer_slack_ns = slack_ns;
2289                task_unlock(p);
2290        } else
2291                count = -EPERM;
2292
2293        put_task_struct(p);
2294
2295        return count;
2296}
2297
2298static int timerslack_ns_show(struct seq_file *m, void *v)
2299{
2300        struct inode *inode = m->private;
2301        struct task_struct *p;
2302        int err =  0;
2303
2304        p = get_proc_task(inode);
2305        if (!p)
2306                return -ESRCH;
2307
2308        if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) {
2309                task_lock(p);
2310                seq_printf(m, "%llu\n", p->timer_slack_ns);
2311                task_unlock(p);
2312        } else
2313                err = -EPERM;
2314
2315        put_task_struct(p);
2316
2317        return err;
2318}
2319
2320static int timerslack_ns_open(struct inode *inode, struct file *filp)
2321{
2322        return single_open(filp, timerslack_ns_show, inode);
2323}
2324
2325static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2326        .open           = timerslack_ns_open,
2327        .read           = seq_read,
2328        .write          = timerslack_ns_write,
2329        .llseek         = seq_lseek,
2330        .release        = single_release,
2331};
2332
2333static int proc_pident_instantiate(struct inode *dir,
2334        struct dentry *dentry, struct task_struct *task, const void *ptr)
2335{
2336        const struct pid_entry *p = ptr;
2337        struct inode *inode;
2338        struct proc_inode *ei;
2339
2340        inode = proc_pid_make_inode(dir->i_sb, task);
2341        if (!inode)
2342                goto out;
2343
2344        ei = PROC_I(inode);
2345        inode->i_mode = p->mode;
2346        if (S_ISDIR(inode->i_mode))
2347                set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2348        if (p->iop)
2349                inode->i_op = p->iop;
2350        if (p->fop)
2351                inode->i_fop = p->fop;
2352        ei->op = p->op;
2353        d_set_d_op(dentry, &pid_dentry_operations);
2354        d_add(dentry, inode);
2355        /* Close the race of the process dying before we return the dentry */
2356        if (pid_revalidate(dentry, 0))
2357                return 0;
2358out:
2359        return -ENOENT;
2360}
2361
2362static struct dentry *proc_pident_lookup(struct inode *dir, 
2363                                         struct dentry *dentry,
2364                                         const struct pid_entry *ents,
2365                                         unsigned int nents)
2366{
2367        int error;
2368        struct task_struct *task = get_proc_task(dir);
2369        const struct pid_entry *p, *last;
2370
2371        error = -ENOENT;
2372
2373        if (!task)
2374                goto out_no_task;
2375
2376        /*
2377         * Yes, it does not scale. And it should not. Don't add
2378         * new entries into /proc/<tgid>/ without very good reasons.
2379         */
2380        last = &ents[nents - 1];
2381        for (p = ents; p <= last; p++) {
2382                if (p->len != dentry->d_name.len)
2383                        continue;
2384                if (!memcmp(dentry->d_name.name, p->name, p->len))
2385                        break;
2386        }
2387        if (p > last)
2388                goto out;
2389
2390        error = proc_pident_instantiate(dir, dentry, task, p);
2391out:
2392        put_task_struct(task);
2393out_no_task:
2394        return ERR_PTR(error);
2395}
2396
2397static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2398                const struct pid_entry *ents, unsigned int nents)
2399{
2400        struct task_struct *task = get_proc_task(file_inode(file));
2401        const struct pid_entry *p;
2402
2403        if (!task)
2404                return -ENOENT;
2405
2406        if (!dir_emit_dots(file, ctx))
2407                goto out;
2408
2409        if (ctx->pos >= nents + 2)
2410                goto out;
2411
2412        for (p = ents + (ctx->pos - 2); p <= ents + nents - 1; p++) {
2413                if (!proc_fill_cache(file, ctx, p->name, p->len,
2414                                proc_pident_instantiate, task, p))
2415                        break;
2416                ctx->pos++;
2417        }
2418out:
2419        put_task_struct(task);
2420        return 0;
2421}
2422
2423#ifdef CONFIG_SECURITY
2424static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2425                                  size_t count, loff_t *ppos)
2426{
2427        struct inode * inode = file_inode(file);
2428        char *p = NULL;
2429        ssize_t length;
2430        struct task_struct *task = get_proc_task(inode);
2431
2432        if (!task)
2433                return -ESRCH;
2434
2435        length = security_getprocattr(task,
2436                                      (char*)file->f_path.dentry->d_name.name,
2437                                      &p);
2438        put_task_struct(task);
2439        if (length > 0)
2440                length = simple_read_from_buffer(buf, count, ppos, p, length);
2441        kfree(p);
2442        return length;
2443}
2444
2445static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2446                                   size_t count, loff_t *ppos)
2447{
2448        struct inode * inode = file_inode(file);
2449        void *page;
2450        ssize_t length;
2451        struct task_struct *task = get_proc_task(inode);
2452
2453        length = -ESRCH;
2454        if (!task)
2455                goto out_no_task;
2456        if (count > PAGE_SIZE)
2457                count = PAGE_SIZE;
2458
2459        /* No partial writes. */
2460        length = -EINVAL;
2461        if (*ppos != 0)
2462                goto out;
2463
2464        page = memdup_user(buf, count);
2465        if (IS_ERR(page)) {
2466                length = PTR_ERR(page);
2467                goto out;
2468        }
2469
2470        /* Guard against adverse ptrace interaction */
2471        length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2472        if (length < 0)
2473                goto out_free;
2474
2475        length = security_setprocattr(task,
2476                                      (char*)file->f_path.dentry->d_name.name,
2477                                      page, count);
2478        mutex_unlock(&task->signal->cred_guard_mutex);
2479out_free:
2480        kfree(page);
2481out:
2482        put_task_struct(task);
2483out_no_task:
2484        return length;
2485}
2486
2487static const struct file_operations proc_pid_attr_operations = {
2488        .read           = proc_pid_attr_read,
2489        .write          = proc_pid_attr_write,
2490        .llseek         = generic_file_llseek,
2491};
2492
2493static const struct pid_entry attr_dir_stuff[] = {
2494        REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2495        REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2496        REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2497        REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2498        REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2499        REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2500};
2501
2502static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2503{
2504        return proc_pident_readdir(file, ctx, 
2505                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2506}
2507
2508static const struct file_operations proc_attr_dir_operations = {
2509        .read           = generic_read_dir,
2510        .iterate_shared = proc_attr_dir_readdir,
2511        .llseek         = generic_file_llseek,
2512};
2513
2514static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2515                                struct dentry *dentry, unsigned int flags)
2516{
2517        return proc_pident_lookup(dir, dentry,
2518                                  attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2519}
2520
2521static const struct inode_operations proc_attr_dir_inode_operations = {
2522        .lookup         = proc_attr_dir_lookup,
2523        .getattr        = pid_getattr,
2524        .setattr        = proc_setattr,
2525};
2526
2527#endif
2528
2529#ifdef CONFIG_ELF_CORE
2530static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2531                                         size_t count, loff_t *ppos)
2532{
2533        struct task_struct *task = get_proc_task(file_inode(file));
2534        struct mm_struct *mm;
2535        char buffer[PROC_NUMBUF];
2536        size_t len;
2537        int ret;
2538
2539        if (!task)
2540                return -ESRCH;
2541
2542        ret = 0;
2543        mm = get_task_mm(task);
2544        if (mm) {
2545                len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2546                               ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2547                                MMF_DUMP_FILTER_SHIFT));
2548                mmput(mm);
2549                ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2550        }
2551
2552        put_task_struct(task);
2553
2554        return ret;
2555}
2556
2557static ssize_t proc_coredump_filter_write(struct file *file,
2558                                          const char __user *buf,
2559                                          size_t count,
2560                                          loff_t *ppos)
2561{
2562        struct task_struct *task;
2563        struct mm_struct *mm;
2564        unsigned int val;
2565        int ret;
2566        int i;
2567        unsigned long mask;
2568
2569        ret = kstrtouint_from_user(buf, count, 0, &val);
2570        if (ret < 0)
2571                return ret;
2572
2573        ret = -ESRCH;
2574        task = get_proc_task(file_inode(file));
2575        if (!task)
2576                goto out_no_task;
2577
2578        mm = get_task_mm(task);
2579        if (!mm)
2580                goto out_no_mm;
2581        ret = 0;
2582
2583        for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2584                if (val & mask)
2585                        set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2586                else
2587                        clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2588        }
2589
2590        mmput(mm);
2591 out_no_mm:
2592        put_task_struct(task);
2593 out_no_task:
2594        if (ret < 0)
2595                return ret;
2596        return count;
2597}
2598
2599static const struct file_operations proc_coredump_filter_operations = {
2600        .read           = proc_coredump_filter_read,
2601        .write          = proc_coredump_filter_write,
2602        .llseek         = generic_file_llseek,
2603};
2604#endif
2605
2606#ifdef CONFIG_TASK_IO_ACCOUNTING
2607static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2608{
2609        struct task_io_accounting acct = task->ioac;
2610        unsigned long flags;
2611        int result;
2612
2613        result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2614        if (result)
2615                return result;
2616
2617        if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2618                result = -EACCES;
2619                goto out_unlock;
2620        }
2621
2622        if (whole && lock_task_sighand(task, &flags)) {
2623                struct task_struct *t = task;
2624
2625                task_io_accounting_add(&acct, &task->signal->ioac);
2626                while_each_thread(task, t)
2627                        task_io_accounting_add(&acct, &t->ioac);
2628
2629                unlock_task_sighand(task, &flags);
2630        }
2631        seq_printf(m,
2632                   "rchar: %llu\n"
2633                   "wchar: %llu\n"
2634                   "syscr: %llu\n"
2635                   "syscw: %llu\n"
2636                   "read_bytes: %llu\n"
2637                   "write_bytes: %llu\n"
2638                   "cancelled_write_bytes: %llu\n",
2639                   (unsigned long long)acct.rchar,
2640                   (unsigned long long)acct.wchar,
2641                   (unsigned long long)acct.syscr,
2642                   (unsigned long long)acct.syscw,
2643                   (unsigned long long)acct.read_bytes,
2644                   (unsigned long long)acct.write_bytes,
2645                   (unsigned long long)acct.cancelled_write_bytes);
2646        result = 0;
2647
2648out_unlock:
2649        mutex_unlock(&task->signal->cred_guard_mutex);
2650        return result;
2651}
2652
2653static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2654                                  struct pid *pid, struct task_struct *task)
2655{
2656        return do_io_accounting(task, m, 0);
2657}
2658
2659static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2660                                   struct pid *pid, struct task_struct *task)
2661{
2662        return do_io_accounting(task, m, 1);
2663}
2664#endif /* CONFIG_TASK_IO_ACCOUNTING */
2665
2666#ifdef CONFIG_USER_NS
2667static int proc_id_map_open(struct inode *inode, struct file *file,
2668        const struct seq_operations *seq_ops)
2669{
2670        struct user_namespace *ns = NULL;
2671        struct task_struct *task;
2672        struct seq_file *seq;
2673        int ret = -EINVAL;
2674
2675        task = get_proc_task(inode);
2676        if (task) {
2677                rcu_read_lock();
2678                ns = get_user_ns(task_cred_xxx(task, user_ns));
2679                rcu_read_unlock();
2680                put_task_struct(task);
2681        }
2682        if (!ns)
2683                goto err;
2684
2685        ret = seq_open(file, seq_ops);
2686        if (ret)
2687                goto err_put_ns;
2688
2689        seq = file->private_data;
2690        seq->private = ns;
2691
2692        return 0;
2693err_put_ns:
2694        put_user_ns(ns);
2695err:
2696        return ret;
2697}
2698
2699static int proc_id_map_release(struct inode *inode, struct file *file)
2700{
2701        struct seq_file *seq = file->private_data;
2702        struct user_namespace *ns = seq->private;
2703        put_user_ns(ns);
2704        return seq_release(inode, file);
2705}
2706
2707static int proc_uid_map_open(struct inode *inode, struct file *file)
2708{
2709        return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2710}
2711
2712static int proc_gid_map_open(struct inode *inode, struct file *file)
2713{
2714        return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2715}
2716
2717static int proc_projid_map_open(struct inode *inode, struct file *file)
2718{
2719        return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2720}
2721
2722static const struct file_operations proc_uid_map_operations = {
2723        .open           = proc_uid_map_open,
2724        .write          = proc_uid_map_write,
2725        .read           = seq_read,
2726        .llseek         = seq_lseek,
2727        .release        = proc_id_map_release,
2728};
2729
2730static const struct file_operations proc_gid_map_operations = {
2731        .open           = proc_gid_map_open,
2732        .write          = proc_gid_map_write,
2733        .read           = seq_read,
2734        .llseek         = seq_lseek,
2735        .release        = proc_id_map_release,
2736};
2737
2738static const struct file_operations proc_projid_map_operations = {
2739        .open           = proc_projid_map_open,
2740        .write          = proc_projid_map_write,
2741        .read           = seq_read,
2742        .llseek         = seq_lseek,
2743        .release        = proc_id_map_release,
2744};
2745
2746static int proc_setgroups_open(struct inode *inode, struct file *file)
2747{
2748        struct user_namespace *ns = NULL;
2749        struct task_struct *task;
2750        int ret;
2751
2752        ret = -ESRCH;
2753        task = get_proc_task(inode);
2754        if (task) {
2755                rcu_read_lock();
2756                ns = get_user_ns(task_cred_xxx(task, user_ns));
2757                rcu_read_unlock();
2758                put_task_struct(task);
2759        }
2760        if (!ns)
2761                goto err;
2762
2763        if (file->f_mode & FMODE_WRITE) {
2764                ret = -EACCES;
2765                if (!ns_capable(ns, CAP_SYS_ADMIN))
2766                        goto err_put_ns;
2767        }
2768
2769        ret = single_open(file, &proc_setgroups_show, ns);
2770        if (ret)
2771                goto err_put_ns;
2772
2773        return 0;
2774err_put_ns:
2775        put_user_ns(ns);
2776err:
2777        return ret;
2778}
2779
2780static int proc_setgroups_release(struct inode *inode, struct file *file)
2781{
2782        struct seq_file *seq = file->private_data;
2783        struct user_namespace *ns = seq->private;
2784        int ret = single_release(inode, file);
2785        put_user_ns(ns);
2786        return ret;
2787}
2788
2789static const struct file_operations proc_setgroups_operations = {
2790        .open           = proc_setgroups_open,
2791        .write          = proc_setgroups_write,
2792        .read           = seq_read,
2793        .llseek         = seq_lseek,
2794        .release        = proc_setgroups_release,
2795};
2796#endif /* CONFIG_USER_NS */
2797
2798static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2799                                struct pid *pid, struct task_struct *task)
2800{
2801        int err = lock_trace(task);
2802        if (!err) {
2803                seq_printf(m, "%08x\n", task->personality);
2804                unlock_trace(task);
2805        }
2806        return err;
2807}
2808
2809/*
2810 * Thread groups
2811 */
2812static const struct file_operations proc_task_operations;
2813static const struct inode_operations proc_task_inode_operations;
2814
2815static const struct pid_entry tgid_base_stuff[] = {
2816        DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2817        DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2818        DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2819        DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2820        DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2821#ifdef CONFIG_NET
2822        DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2823#endif
2824        REG("environ",    S_IRUSR, proc_environ_operations),
2825        ONE("auxv",       S_IRUSR, proc_pid_auxv),
2826        ONE("status",     S_IRUGO, proc_pid_status),
2827        ONE("personality", S_IRUSR, proc_pid_personality),
2828        ONE("limits",     S_IRUGO, proc_pid_limits),
2829#ifdef CONFIG_SCHED_DEBUG
2830        REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2831#endif
2832#ifdef CONFIG_SCHED_AUTOGROUP
2833        REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2834#endif
2835        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2836#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2837        ONE("syscall",    S_IRUSR, proc_pid_syscall),
2838#endif
2839        REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
2840        ONE("stat",       S_IRUGO, proc_tgid_stat),
2841        ONE("statm",      S_IRUGO, proc_pid_statm),
2842        REG("maps",       S_IRUGO, proc_pid_maps_operations),
2843#ifdef CONFIG_NUMA
2844        REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2845#endif
2846        REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2847        LNK("cwd",        proc_cwd_link),
2848        LNK("root",       proc_root_link),
2849        LNK("exe",        proc_exe_link),
2850        REG("mounts",     S_IRUGO, proc_mounts_operations),
2851        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2852        REG("mountstats", S_IRUSR, proc_mountstats_operations),
2853#ifdef CONFIG_PROC_PAGE_MONITOR
2854        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2855        REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2856        REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2857#endif
2858#ifdef CONFIG_SECURITY
2859        DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2860#endif
2861#ifdef CONFIG_KALLSYMS
2862        ONE("wchan",      S_IRUGO, proc_pid_wchan),
2863#endif
2864#ifdef CONFIG_STACKTRACE
2865        ONE("stack",      S_IRUSR, proc_pid_stack),
2866#endif
2867#ifdef CONFIG_SCHED_INFO
2868        ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
2869#endif
2870#ifdef CONFIG_LATENCYTOP
2871        REG("latency",  S_IRUGO, proc_lstats_operations),
2872#endif
2873#ifdef CONFIG_PROC_PID_CPUSET
2874        ONE("cpuset",     S_IRUGO, proc_cpuset_show),
2875#endif
2876#ifdef CONFIG_CGROUPS
2877        ONE("cgroup",  S_IRUGO, proc_cgroup_show),
2878#endif
2879        ONE("oom_score",  S_IRUGO, proc_oom_score),
2880        REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
2881        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2882#ifdef CONFIG_AUDITSYSCALL
2883        REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2884        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2885#endif
2886#ifdef CONFIG_FAULT_INJECTION
2887        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2888#endif
2889#ifdef CONFIG_ELF_CORE
2890        REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2891#endif
2892#ifdef CONFIG_TASK_IO_ACCOUNTING
2893        ONE("io",       S_IRUSR, proc_tgid_io_accounting),
2894#endif
2895#ifdef CONFIG_HARDWALL
2896        ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
2897#endif
2898#ifdef CONFIG_USER_NS
2899        REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
2900        REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
2901        REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
2902        REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
2903#endif
2904#ifdef CONFIG_CHECKPOINT_RESTORE
2905        REG("timers",     S_IRUGO, proc_timers_operations),
2906#endif
2907        REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
2908};
2909
2910static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
2911{
2912        return proc_pident_readdir(file, ctx,
2913                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2914}
2915
2916static const struct file_operations proc_tgid_base_operations = {
2917        .read           = generic_read_dir,
2918        .iterate_shared = proc_tgid_base_readdir,
2919        .llseek         = generic_file_llseek,
2920};
2921
2922static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
2923{
2924        return proc_pident_lookup(dir, dentry,
2925                                  tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2926}
2927
2928static const struct inode_operations proc_tgid_base_inode_operations = {
2929        .lookup         = proc_tgid_base_lookup,
2930        .getattr        = pid_getattr,
2931        .setattr        = proc_setattr,
2932        .permission     = proc_pid_permission,
2933};
2934
2935static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2936{
2937        struct dentry *dentry, *leader, *dir;
2938        char buf[PROC_NUMBUF];
2939        struct qstr name;
2940
2941        name.name = buf;
2942        name.len = snprintf(buf, sizeof(buf), "%d", pid);
2943        /* no ->d_hash() rejects on procfs */
2944        dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2945        if (dentry) {
2946                d_invalidate(dentry);
2947                dput(dentry);
2948        }
2949
2950        if (pid == tgid)
2951                return;
2952
2953        name.name = buf;
2954        name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2955        leader = d_hash_and_lookup(mnt->mnt_root, &name);
2956        if (!leader)
2957                goto out;
2958
2959        name.name = "task";
2960        name.len = strlen(name.name);
2961        dir = d_hash_and_lookup(leader, &name);
2962        if (!dir)
2963                goto out_put_leader;
2964
2965        name.name = buf;
2966        name.len = snprintf(buf, sizeof(buf), "%d", pid);
2967        dentry = d_hash_and_lookup(dir, &name);
2968        if (dentry) {
2969                d_invalidate(dentry);
2970                dput(dentry);
2971        }
2972
2973        dput(dir);
2974out_put_leader:
2975        dput(leader);
2976out:
2977        return;
2978}
2979
2980/**
2981 * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2982 * @task: task that should be flushed.
2983 *
2984 * When flushing dentries from proc, one needs to flush them from global
2985 * proc (proc_mnt) and from all the namespaces' procs this task was seen
2986 * in. This call is supposed to do all of this job.
2987 *
2988 * Looks in the dcache for
2989 * /proc/@pid
2990 * /proc/@tgid/task/@pid
2991 * if either directory is present flushes it and all of it'ts children
2992 * from the dcache.
2993 *
2994 * It is safe and reasonable to cache /proc entries for a task until
2995 * that task exits.  After that they just clog up the dcache with
2996 * useless entries, possibly causing useful dcache entries to be
2997 * flushed instead.  This routine is proved to flush those useless
2998 * dcache entries at process exit time.
2999 *
3000 * NOTE: This routine is just an optimization so it does not guarantee
3001 *       that no dcache entries will exist at process exit time it
3002 *       just makes it very unlikely that any will persist.
3003 */
3004
3005void proc_flush_task(struct task_struct *task)
3006{
3007        int i;
3008        struct pid *pid, *tgid;
3009        struct upid *upid;
3010
3011        pid = task_pid(task);
3012        tgid = task_tgid(task);
3013
3014        for (i = 0; i <= pid->level; i++) {
3015                upid = &pid->numbers[i];
3016                proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3017                                        tgid->numbers[i].nr);
3018        }
3019}
3020
3021static int proc_pid_instantiate(struct inode *dir,
3022                                   struct dentry * dentry,
3023                                   struct task_struct *task, const void *ptr)
3024{
3025        struct inode *inode;
3026
3027        inode = proc_pid_make_inode(dir->i_sb, task);
3028        if (!inode)
3029                goto out;
3030
3031        inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3032        inode->i_op = &proc_tgid_base_inode_operations;
3033        inode->i_fop = &proc_tgid_base_operations;
3034        inode->i_flags|=S_IMMUTABLE;
3035
3036        set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
3037                                                  ARRAY_SIZE(tgid_base_stuff)));
3038
3039        d_set_d_op(dentry, &pid_dentry_operations);
3040
3041        d_add(dentry, inode);
3042        /* Close the race of the process dying before we return the dentry */
3043        if (pid_revalidate(dentry, 0))
3044                return 0;
3045out:
3046        return -ENOENT;
3047}
3048
3049struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3050{
3051        int result = -ENOENT;
3052        struct task_struct *task;
3053        unsigned tgid;
3054        struct pid_namespace *ns;
3055
3056        tgid = name_to_int(&dentry->d_name);
3057        if (tgid == ~0U)
3058                goto out;
3059
3060        ns = dentry->d_sb->s_fs_info;
3061        rcu_read_lock();
3062        task = find_task_by_pid_ns(tgid, ns);
3063        if (task)
3064                get_task_struct(task);
3065        rcu_read_unlock();
3066        if (!task)
3067                goto out;
3068
3069        result = proc_pid_instantiate(dir, dentry, task, NULL);
3070        put_task_struct(task);
3071out:
3072        return ERR_PTR(result);
3073}
3074
3075/*
3076 * Find the first task with tgid >= tgid
3077 *
3078 */
3079struct tgid_iter {
3080        unsigned int tgid;
3081        struct task_struct *task;
3082};
3083static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3084{
3085        struct pid *pid;
3086
3087        if (iter.task)
3088                put_task_struct(iter.task);
3089        rcu_read_lock();
3090retry:
3091        iter.task = NULL;
3092        pid = find_ge_pid(iter.tgid, ns);
3093        if (pid) {
3094                iter.tgid = pid_nr_ns(pid, ns);
3095                iter.task = pid_task(pid, PIDTYPE_PID);
3096                /* What we to know is if the pid we have find is the
3097                 * pid of a thread_group_leader.  Testing for task
3098                 * being a thread_group_leader is the obvious thing
3099                 * todo but there is a window when it fails, due to
3100                 * the pid transfer logic in de_thread.
3101                 *
3102                 * So we perform the straight forward test of seeing
3103                 * if the pid we have found is the pid of a thread
3104                 * group leader, and don't worry if the task we have
3105                 * found doesn't happen to be a thread group leader.
3106                 * As we don't care in the case of readdir.
3107                 */
3108                if (!iter.task || !has_group_leader_pid(iter.task)) {
3109                        iter.tgid += 1;
3110                        goto retry;
3111                }
3112                get_task_struct(iter.task);
3113        }
3114        rcu_read_unlock();
3115        return iter;
3116}
3117
3118#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3119
3120/* for the /proc/ directory itself, after non-process stuff has been done */
3121int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3122{
3123        struct tgid_iter iter;
3124        struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info;
3125        loff_t pos = ctx->pos;
3126
3127        if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3128                return 0;
3129
3130        if (pos == TGID_OFFSET - 2) {
3131                struct inode *inode = d_inode(ns->proc_self);
3132                if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3133                        return 0;
3134                ctx->pos = pos = pos + 1;
3135        }
3136        if (pos == TGID_OFFSET - 1) {
3137                struct inode *inode = d_inode(ns->proc_thread_self);
3138                if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3139                        return 0;
3140                ctx->pos = pos = pos + 1;
3141        }
3142        iter.tgid = pos - TGID_OFFSET;
3143        iter.task = NULL;
3144        for (iter = next_tgid(ns, iter);
3145             iter.task;
3146             iter.tgid += 1, iter = next_tgid(ns, iter)) {
3147                char name[PROC_NUMBUF];
3148                int len;
3149                if (!has_pid_permissions(ns, iter.task, 2))
3150                        continue;
3151
3152                len = snprintf(name, sizeof(name), "%d", iter.tgid);
3153                ctx->pos = iter.tgid + TGID_OFFSET;
3154                if (!proc_fill_cache(file, ctx, name, len,
3155                                     proc_pid_instantiate, iter.task, NULL)) {
3156                        put_task_struct(iter.task);
3157                        return 0;
3158                }
3159        }
3160        ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3161        return 0;
3162}
3163
3164/*
3165 * proc_tid_comm_permission is a special permission function exclusively
3166 * used for the node /proc/<pid>/task/<tid>/comm.
3167 * It bypasses generic permission checks in the case where a task of the same
3168 * task group attempts to access the node.
3169 * The rationale behind this is that glibc and bionic access this node for
3170 * cross thread naming (pthread_set/getname_np(!self)). However, if
3171 * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3172 * which locks out the cross thread naming implementation.
3173 * This function makes sure that the node is always accessible for members of
3174 * same thread group.
3175 */
3176static int proc_tid_comm_permission(struct inode *inode, int mask)
3177{
3178        bool is_same_tgroup;
3179        struct task_struct *task;
3180
3181        task = get_proc_task(inode);
3182        if (!task)
3183                return -ESRCH;
3184        is_same_tgroup = same_thread_group(current, task);
3185        put_task_struct(task);
3186
3187        if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3188                /* This file (/proc/<pid>/task/<tid>/comm) can always be
3189                 * read or written by the members of the corresponding
3190                 * thread group.
3191                 */
3192                return 0;
3193        }
3194
3195        return generic_permission(inode, mask);
3196}
3197
3198static const struct inode_operations proc_tid_comm_inode_operations = {
3199                .permission = proc_tid_comm_permission,
3200};
3201
3202/*
3203 * Tasks
3204 */
3205static const struct pid_entry tid_base_stuff[] = {
3206        DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3207        DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3208        DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3209#ifdef CONFIG_NET
3210        DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3211#endif
3212        REG("environ",   S_IRUSR, proc_environ_operations),
3213        ONE("auxv",      S_IRUSR, proc_pid_auxv),
3214        ONE("status",    S_IRUGO, proc_pid_status),
3215        ONE("personality", S_IRUSR, proc_pid_personality),
3216        ONE("limits",    S_IRUGO, proc_pid_limits),
3217#ifdef CONFIG_SCHED_DEBUG
3218        REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3219#endif
3220        NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3221                         &proc_tid_comm_inode_operations,
3222                         &proc_pid_set_comm_operations, {}),
3223#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3224        ONE("syscall",   S_IRUSR, proc_pid_syscall),
3225#endif
3226        REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3227        ONE("stat",      S_IRUGO, proc_tid_stat),
3228        ONE("statm",     S_IRUGO, proc_pid_statm),
3229        REG("maps",      S_IRUGO, proc_tid_maps_operations),
3230#ifdef CONFIG_PROC_CHILDREN
3231        REG("children",  S_IRUGO, proc_tid_children_operations),
3232#endif
3233#ifdef CONFIG_NUMA
3234        REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3235#endif
3236        REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3237        LNK("cwd",       proc_cwd_link),
3238        LNK("root",      proc_root_link),
3239        LNK("exe",       proc_exe_link),
3240        REG("mounts",    S_IRUGO, proc_mounts_operations),
3241        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3242#ifdef CONFIG_PROC_PAGE_MONITOR
3243        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3244        REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3245        REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3246#endif
3247#ifdef CONFIG_SECURITY
3248        DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3249#endif
3250#ifdef CONFIG_KALLSYMS
3251        ONE("wchan",     S_IRUGO, proc_pid_wchan),
3252#endif
3253#ifdef CONFIG_STACKTRACE
3254        ONE("stack",      S_IRUSR, proc_pid_stack),
3255#endif
3256#ifdef CONFIG_SCHED_INFO
3257        ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3258#endif
3259#ifdef CONFIG_LATENCYTOP
3260        REG("latency",  S_IRUGO, proc_lstats_operations),
3261#endif
3262#ifdef CONFIG_PROC_PID_CPUSET
3263        ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3264#endif
3265#ifdef CONFIG_CGROUPS
3266        ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3267#endif
3268        ONE("oom_score", S_IRUGO, proc_oom_score),
3269        REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3270        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3271#ifdef CONFIG_AUDITSYSCALL
3272        REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3273        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3274#endif
3275#ifdef CONFIG_FAULT_INJECTION
3276        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3277#endif
3278#ifdef CONFIG_TASK_IO_ACCOUNTING
3279        ONE("io",       S_IRUSR, proc_tid_io_accounting),
3280#endif
3281#ifdef CONFIG_HARDWALL
3282        ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
3283#endif
3284#ifdef CONFIG_USER_NS
3285        REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3286        REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3287        REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3288        REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3289#endif
3290};
3291
3292static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3293{
3294        return proc_pident_readdir(file, ctx,
3295                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3296}
3297
3298static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3299{
3300        return proc_pident_lookup(dir, dentry,
3301                                  tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3302}
3303
3304static const struct file_operations proc_tid_base_operations = {
3305        .read           = generic_read_dir,
3306        .iterate_shared = proc_tid_base_readdir,
3307        .llseek         = generic_file_llseek,
3308};
3309
3310static const struct inode_operations proc_tid_base_inode_operations = {
3311        .lookup         = proc_tid_base_lookup,
3312        .getattr        = pid_getattr,
3313        .setattr        = proc_setattr,
3314};
3315
3316static int proc_task_instantiate(struct inode *dir,
3317        struct dentry *dentry, struct task_struct *task, const void *ptr)
3318{
3319        struct inode *inode;
3320        inode = proc_pid_make_inode(dir->i_sb, task);
3321
3322        if (!inode)
3323                goto out;
3324        inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3325        inode->i_op = &proc_tid_base_inode_operations;
3326        inode->i_fop = &proc_tid_base_operations;
3327        inode->i_flags|=S_IMMUTABLE;
3328
3329        set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
3330                                                  ARRAY_SIZE(tid_base_stuff)));
3331
3332        d_set_d_op(dentry, &pid_dentry_operations);
3333
3334        d_add(dentry, inode);
3335        /* Close the race of the process dying before we return the dentry */
3336        if (pid_revalidate(dentry, 0))
3337                return 0;
3338out:
3339        return -ENOENT;
3340}
3341
3342static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3343{
3344        int result = -ENOENT;
3345        struct task_struct *task;
3346        struct task_struct *leader = get_proc_task(dir);
3347        unsigned tid;
3348        struct pid_namespace *ns;
3349
3350        if (!leader)
3351                goto out_no_task;
3352
3353        tid = name_to_int(&dentry->d_name);
3354        if (tid == ~0U)
3355                goto out;
3356
3357        ns = dentry->d_sb->s_fs_info;
3358        rcu_read_lock();
3359        task = find_task_by_pid_ns(tid, ns);
3360        if (task)
3361                get_task_struct(task);
3362        rcu_read_unlock();
3363        if (!task)
3364                goto out;
3365        if (!same_thread_group(leader, task))
3366                goto out_drop_task;
3367
3368        result = proc_task_instantiate(dir, dentry, task, NULL);
3369out_drop_task:
3370        put_task_struct(task);
3371out:
3372        put_task_struct(leader);
3373out_no_task:
3374        return ERR_PTR(result);
3375}
3376
3377/*
3378 * Find the first tid of a thread group to return to user space.
3379 *
3380 * Usually this is just the thread group leader, but if the users
3381 * buffer was too small or there was a seek into the middle of the
3382 * directory we have more work todo.
3383 *
3384 * In the case of a short read we start with find_task_by_pid.
3385 *
3386 * In the case of a seek we start with the leader and walk nr
3387 * threads past it.
3388 */
3389static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3390                                        struct pid_namespace *ns)
3391{
3392        struct task_struct *pos, *task;
3393        unsigned long nr = f_pos;
3394
3395        if (nr != f_pos)        /* 32bit overflow? */
3396                return NULL;
3397
3398        rcu_read_lock();
3399        task = pid_task(pid, PIDTYPE_PID);
3400        if (!task)
3401                goto fail;
3402
3403        /* Attempt to start with the tid of a thread */
3404        if (tid && nr) {
3405                pos = find_task_by_pid_ns(tid, ns);
3406                if (pos && same_thread_group(pos, task))
3407                        goto found;
3408        }
3409
3410        /* If nr exceeds the number of threads there is nothing todo */
3411        if (nr >= get_nr_threads(task))
3412                goto fail;
3413
3414        /* If we haven't found our starting place yet start
3415         * with the leader and walk nr threads forward.
3416         */
3417        pos = task = task->group_leader;
3418        do {
3419                if (!nr--)
3420                        goto found;
3421        } while_each_thread(task, pos);
3422fail:
3423        pos = NULL;
3424        goto out;
3425found:
3426        get_task_struct(pos);
3427out:
3428        rcu_read_unlock();
3429        return pos;
3430}
3431
3432/*
3433 * Find the next thread in the thread list.
3434 * Return NULL if there is an error or no next thread.
3435 *
3436 * The reference to the input task_struct is released.
3437 */
3438static struct task_struct *next_tid(struct task_struct *start)
3439{
3440        struct task_struct *pos = NULL;
3441        rcu_read_lock();
3442        if (pid_alive(start)) {
3443                pos = next_thread(start);
3444                if (thread_group_leader(pos))
3445                        pos = NULL;
3446                else
3447                        get_task_struct(pos);
3448        }
3449        rcu_read_unlock();
3450        put_task_struct(start);
3451        return pos;
3452}
3453
3454/* for the /proc/TGID/task/ directories */
3455static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3456{
3457        struct inode *inode = file_inode(file);
3458        struct task_struct *task;
3459        struct pid_namespace *ns;
3460        int tid;
3461
3462        if (proc_inode_is_dead(inode))
3463                return -ENOENT;
3464
3465        if (!dir_emit_dots(file, ctx))
3466                return 0;
3467
3468        /* f_version caches the tgid value that the last readdir call couldn't
3469         * return. lseek aka telldir automagically resets f_version to 0.
3470         */
3471        ns = inode->i_sb->s_fs_info;
3472        tid = (int)file->f_version;
3473        file->f_version = 0;
3474        for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3475             task;
3476             task = next_tid(task), ctx->pos++) {
3477                char name[PROC_NUMBUF];
3478                int len;
3479                tid = task_pid_nr_ns(task, ns);
3480                len = snprintf(name, sizeof(name), "%d", tid);
3481                if (!proc_fill_cache(file, ctx, name, len,
3482                                proc_task_instantiate, task, NULL)) {
3483                        /* returning this tgid failed, save it as the first
3484                         * pid for the next readir call */
3485                        file->f_version = (u64)tid;
3486                        put_task_struct(task);
3487                        break;
3488                }
3489        }
3490
3491        return 0;
3492}
3493
3494static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3495{
3496        struct inode *inode = d_inode(dentry);
3497        struct task_struct *p = get_proc_task(inode);
3498        generic_fillattr(inode, stat);
3499
3500        if (p) {
3501                stat->nlink += get_nr_threads(p);
3502                put_task_struct(p);
3503        }
3504
3505        return 0;
3506}
3507
3508static const struct inode_operations proc_task_inode_operations = {
3509        .lookup         = proc_task_lookup,
3510        .getattr        = proc_task_getattr,
3511        .setattr        = proc_setattr,
3512        .permission     = proc_pid_permission,
3513};
3514
3515static const struct file_operations proc_task_operations = {
3516        .read           = generic_read_dir,
3517        .iterate_shared = proc_task_readdir,
3518        .llseek         = generic_file_llseek,
3519};
3520
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