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/cgroup.h>
  77#include <linux/cpuset.h>
  78#include <linux/audit.h>
  79#include <linux/poll.h>
  80#include <linux/nsproxy.h>
  81#include <linux/oom.h>
  82#include <linux/elf.h>
  83#include <linux/pid_namespace.h>
  84#include <linux/fs_struct.h>
  85#include <linux/slab.h>
  86#ifdef CONFIG_HARDWALL
  87#include <asm/hardwall.h>
  88#endif
  89#include "internal.h"
  90
  91/* NOTE:
  92 *      Implementing inode permission operations in /proc is almost
  93 *      certainly an error.  Permission checks need to happen during
  94 *      each system call not at open time.  The reason is that most of
  95 *      what we wish to check for permissions in /proc varies at runtime.
  96 *
  97 *      The classic example of a problem is opening file descriptors
  98 *      in /proc for a task before it execs a suid executable.
  99 */
 100
 101struct pid_entry {
 102        char *name;
 103        int len;
 104        mode_t mode;
 105        const struct inode_operations *iop;
 106        const struct file_operations *fop;
 107        union proc_op op;
 108};
 109
 110#define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 111        .name = (NAME),                                 \
 112        .len  = sizeof(NAME) - 1,                       \
 113        .mode = MODE,                                   \
 114        .iop  = IOP,                                    \
 115        .fop  = FOP,                                    \
 116        .op   = OP,                                     \
 117}
 118
 119#define DIR(NAME, MODE, iops, fops)     \
 120        NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 121#define LNK(NAME, get_link)                                     \
 122        NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 123                &proc_pid_link_inode_operations, NULL,          \
 124                { .proc_get_link = get_link } )
 125#define REG(NAME, MODE, fops)                           \
 126        NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 127#define INF(NAME, MODE, read)                           \
 128        NOD(NAME, (S_IFREG|(MODE)),                     \
 129                NULL, &proc_info_file_operations,       \
 130                { .proc_read = read } )
 131#define ONE(NAME, MODE, show)                           \
 132        NOD(NAME, (S_IFREG|(MODE)),                     \
 133                NULL, &proc_single_file_operations,     \
 134                { .proc_show = show } )
 135
 136/*
 137 * Count the number of hardlinks for the pid_entry table, excluding the .
 138 * and .. links.
 139 */
 140static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
 141        unsigned int n)
 142{
 143        unsigned int i;
 144        unsigned int count;
 145
 146        count = 0;
 147        for (i = 0; i < n; ++i) {
 148                if (S_ISDIR(entries[i].mode))
 149                        ++count;
 150        }
 151
 152        return count;
 153}
 154
 155static int get_task_root(struct task_struct *task, struct path *root)
 156{
 157        int result = -ENOENT;
 158
 159        task_lock(task);
 160        if (task->fs) {
 161                get_fs_root(task->fs, root);
 162                result = 0;
 163        }
 164        task_unlock(task);
 165        return result;
 166}
 167
 168static int proc_cwd_link(struct inode *inode, struct path *path)
 169{
 170        struct task_struct *task = get_proc_task(inode);
 171        int result = -ENOENT;
 172
 173        if (task) {
 174                task_lock(task);
 175                if (task->fs) {
 176                        get_fs_pwd(task->fs, path);
 177                        result = 0;
 178                }
 179                task_unlock(task);
 180                put_task_struct(task);
 181        }
 182        return result;
 183}
 184
 185static int proc_root_link(struct inode *inode, struct path *path)
 186{
 187        struct task_struct *task = get_proc_task(inode);
 188        int result = -ENOENT;
 189
 190        if (task) {
 191                result = get_task_root(task, path);
 192                put_task_struct(task);
 193        }
 194        return result;
 195}
 196
 197static struct mm_struct *__check_mem_permission(struct task_struct *task)
 198{
 199        struct mm_struct *mm;
 200
 201        mm = get_task_mm(task);
 202        if (!mm)
 203                return ERR_PTR(-EINVAL);
 204
 205        /*
 206         * A task can always look at itself, in case it chooses
 207         * to use system calls instead of load instructions.
 208         */
 209        if (task == current)
 210                return mm;
 211
 212        /*
 213         * If current is actively ptrace'ing, and would also be
 214         * permitted to freshly attach with ptrace now, permit it.
 215         */
 216        if (task_is_stopped_or_traced(task)) {
 217                int match;
 218                rcu_read_lock();
 219                match = (tracehook_tracer_task(task) == current);
 220                rcu_read_unlock();
 221                if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
 222                        return mm;
 223        }
 224
 225        /*
 226         * No one else is allowed.
 227         */
 228        mmput(mm);
 229        return ERR_PTR(-EPERM);
 230}
 231
 232/*
 233 * If current may access user memory in @task return a reference to the
 234 * corresponding mm, otherwise ERR_PTR.
 235 */
 236static struct mm_struct *check_mem_permission(struct task_struct *task)
 237{
 238        struct mm_struct *mm;
 239        int err;
 240
 241        /*
 242         * Avoid racing if task exec's as we might get a new mm but validate
 243         * against old credentials.
 244         */
 245        err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 246        if (err)
 247                return ERR_PTR(err);
 248
 249        mm = __check_mem_permission(task);
 250        mutex_unlock(&task->signal->cred_guard_mutex);
 251
 252        return mm;
 253}
 254
 255struct mm_struct *mm_for_maps(struct task_struct *task)
 256{
 257        struct mm_struct *mm;
 258        int err;
 259
 260        err =  mutex_lock_killable(&task->signal->cred_guard_mutex);
 261        if (err)
 262                return ERR_PTR(err);
 263
 264        mm = get_task_mm(task);
 265        if (mm && mm != current->mm &&
 266                        !ptrace_may_access(task, PTRACE_MODE_READ)) {
 267                mmput(mm);
 268                mm = ERR_PTR(-EACCES);
 269        }
 270        mutex_unlock(&task->signal->cred_guard_mutex);
 271
 272        return mm;
 273}
 274
 275static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 276{
 277        int res = 0;
 278        unsigned int len;
 279        struct mm_struct *mm = get_task_mm(task);
 280        if (!mm)
 281                goto out;
 282        if (!mm->arg_end)
 283                goto out_mm;    /* Shh! No looking before we're done */
 284
 285        len = mm->arg_end - mm->arg_start;
 286 
 287        if (len > PAGE_SIZE)
 288                len = PAGE_SIZE;
 289 
 290        res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 291
 292        // If the nul at the end of args has been overwritten, then
 293        // assume application is using setproctitle(3).
 294        if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 295                len = strnlen(buffer, res);
 296                if (len < res) {
 297                    res = len;
 298                } else {
 299                        len = mm->env_end - mm->env_start;
 300                        if (len > PAGE_SIZE - res)
 301                                len = PAGE_SIZE - res;
 302                        res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 303                        res = strnlen(buffer, res);
 304                }
 305        }
 306out_mm:
 307        mmput(mm);
 308out:
 309        return res;
 310}
 311
 312static int proc_pid_auxv(struct task_struct *task, char *buffer)
 313{
 314        struct mm_struct *mm = mm_for_maps(task);
 315        int res = PTR_ERR(mm);
 316        if (mm && !IS_ERR(mm)) {
 317                unsigned int nwords = 0;
 318                do {
 319                        nwords += 2;
 320                } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 321                res = nwords * sizeof(mm->saved_auxv[0]);
 322                if (res > PAGE_SIZE)
 323                        res = PAGE_SIZE;
 324                memcpy(buffer, mm->saved_auxv, res);
 325                mmput(mm);
 326        }
 327        return res;
 328}
 329
 330
 331#ifdef CONFIG_KALLSYMS
 332/*
 333 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 334 * Returns the resolved symbol.  If that fails, simply return the address.
 335 */
 336static int proc_pid_wchan(struct task_struct *task, char *buffer)
 337{
 338        unsigned long wchan;
 339        char symname[KSYM_NAME_LEN];
 340
 341        wchan = get_wchan(task);
 342
 343        if (lookup_symbol_name(wchan, symname) < 0)
 344                if (!ptrace_may_access(task, PTRACE_MODE_READ))
 345                        return 0;
 346                else
 347                        return sprintf(buffer, "%lu", wchan);
 348        else
 349                return sprintf(buffer, "%s", symname);
 350}
 351#endif /* CONFIG_KALLSYMS */
 352
 353static int lock_trace(struct task_struct *task)
 354{
 355        int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 356        if (err)
 357                return err;
 358        if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
 359                mutex_unlock(&task->signal->cred_guard_mutex);
 360                return -EPERM;
 361        }
 362        return 0;
 363}
 364
 365static void unlock_trace(struct task_struct *task)
 366{
 367        mutex_unlock(&task->signal->cred_guard_mutex);
 368}
 369
 370#ifdef CONFIG_STACKTRACE
 371
 372#define MAX_STACK_TRACE_DEPTH   64
 373
 374static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 375                          struct pid *pid, struct task_struct *task)
 376{
 377        struct stack_trace trace;
 378        unsigned long *entries;
 379        int err;
 380        int i;
 381
 382        entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 383        if (!entries)
 384                return -ENOMEM;
 385
 386        trace.nr_entries        = 0;
 387        trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 388        trace.entries           = entries;
 389        trace.skip              = 0;
 390
 391        err = lock_trace(task);
 392        if (!err) {
 393                save_stack_trace_tsk(task, &trace);
 394
 395                for (i = 0; i < trace.nr_entries; i++) {
 396                        seq_printf(m, "[<%pK>] %pS\n",
 397                                   (void *)entries[i], (void *)entries[i]);
 398                }
 399                unlock_trace(task);
 400        }
 401        kfree(entries);
 402
 403        return err;
 404}
 405#endif
 406
 407#ifdef CONFIG_SCHEDSTATS
 408/*
 409 * Provides /proc/PID/schedstat
 410 */
 411static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 412{
 413        return sprintf(buffer, "%llu %llu %lu\n",
 414                        (unsigned long long)task->se.sum_exec_runtime,
 415                        (unsigned long long)task->sched_info.run_delay,
 416                        task->sched_info.pcount);
 417}
 418#endif
 419
 420#ifdef CONFIG_LATENCYTOP
 421static int lstats_show_proc(struct seq_file *m, void *v)
 422{
 423        int i;
 424        struct inode *inode = m->private;
 425        struct task_struct *task = get_proc_task(inode);
 426
 427        if (!task)
 428                return -ESRCH;
 429        seq_puts(m, "Latency Top version : v0.1\n");
 430        for (i = 0; i < 32; i++) {
 431                struct latency_record *lr = &task->latency_record[i];
 432                if (lr->backtrace[0]) {
 433                        int q;
 434                        seq_printf(m, "%i %li %li",
 435                                   lr->count, lr->time, lr->max);
 436                        for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 437                                unsigned long bt = lr->backtrace[q];
 438                                if (!bt)
 439                                        break;
 440                                if (bt == ULONG_MAX)
 441                                        break;
 442                                seq_printf(m, " %ps", (void *)bt);
 443                        }
 444                        seq_putc(m, '\n');
 445                }
 446
 447        }
 448        put_task_struct(task);
 449        return 0;
 450}
 451
 452static int lstats_open(struct inode *inode, struct file *file)
 453{
 454        return single_open(file, lstats_show_proc, inode);
 455}
 456
 457static ssize_t lstats_write(struct file *file, const char __user *buf,
 458                            size_t count, loff_t *offs)
 459{
 460        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 461
 462        if (!task)
 463                return -ESRCH;
 464        clear_all_latency_tracing(task);
 465        put_task_struct(task);
 466
 467        return count;
 468}
 469
 470static const struct file_operations proc_lstats_operations = {
 471        .open           = lstats_open,
 472        .read           = seq_read,
 473        .write          = lstats_write,
 474        .llseek         = seq_lseek,
 475        .release        = single_release,
 476};
 477
 478#endif
 479
 480static int proc_oom_score(struct task_struct *task, char *buffer)
 481{
 482        unsigned long points = 0;
 483
 484        read_lock(&tasklist_lock);
 485        if (pid_alive(task))
 486                points = oom_badness(task, NULL, NULL,
 487                                        totalram_pages + total_swap_pages);
 488        read_unlock(&tasklist_lock);
 489        return sprintf(buffer, "%lu\n", points);
 490}
 491
 492struct limit_names {
 493        char *name;
 494        char *unit;
 495};
 496
 497static const struct limit_names lnames[RLIM_NLIMITS] = {
 498        [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 499        [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 500        [RLIMIT_DATA] = {"Max data size", "bytes"},
 501        [RLIMIT_STACK] = {"Max stack size", "bytes"},
 502        [RLIMIT_CORE] = {"Max core file size", "bytes"},
 503        [RLIMIT_RSS] = {"Max resident set", "bytes"},
 504        [RLIMIT_NPROC] = {"Max processes", "processes"},
 505        [RLIMIT_NOFILE] = {"Max open files", "files"},
 506        [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 507        [RLIMIT_AS] = {"Max address space", "bytes"},
 508        [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 509        [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 510        [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 511        [RLIMIT_NICE] = {"Max nice priority", NULL},
 512        [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 513        [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 514};
 515
 516/* Display limits for a process */
 517static int proc_pid_limits(struct task_struct *task, char *buffer)
 518{
 519        unsigned int i;
 520        int count = 0;
 521        unsigned long flags;
 522        char *bufptr = buffer;
 523
 524        struct rlimit rlim[RLIM_NLIMITS];
 525
 526        if (!lock_task_sighand(task, &flags))
 527                return 0;
 528        memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 529        unlock_task_sighand(task, &flags);
 530
 531        /*
 532         * print the file header
 533         */
 534        count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
 535                        "Limit", "Soft Limit", "Hard Limit", "Units");
 536
 537        for (i = 0; i < RLIM_NLIMITS; i++) {
 538                if (rlim[i].rlim_cur == RLIM_INFINITY)
 539                        count += sprintf(&bufptr[count], "%-25s %-20s ",
 540                                         lnames[i].name, "unlimited");
 541                else
 542                        count += sprintf(&bufptr[count], "%-25s %-20lu ",
 543                                         lnames[i].name, rlim[i].rlim_cur);
 544
 545                if (rlim[i].rlim_max == RLIM_INFINITY)
 546                        count += sprintf(&bufptr[count], "%-20s ", "unlimited");
 547                else
 548                        count += sprintf(&bufptr[count], "%-20lu ",
 549                                         rlim[i].rlim_max);
 550
 551                if (lnames[i].unit)
 552                        count += sprintf(&bufptr[count], "%-10s\n",
 553                                         lnames[i].unit);
 554                else
 555                        count += sprintf(&bufptr[count], "\n");
 556        }
 557
 558        return count;
 559}
 560
 561#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 562static int proc_pid_syscall(struct task_struct *task, char *buffer)
 563{
 564        long nr;
 565        unsigned long args[6], sp, pc;
 566        int res = lock_trace(task);
 567        if (res)
 568                return res;
 569
 570        if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 571                res = sprintf(buffer, "running\n");
 572        else if (nr < 0)
 573                res = sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 574        else
 575                res = sprintf(buffer,
 576                       "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 577                       nr,
 578                       args[0], args[1], args[2], args[3], args[4], args[5],
 579                       sp, pc);
 580        unlock_trace(task);
 581        return res;
 582}
 583#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 584
 585/************************************************************************/
 586/*                       Here the fs part begins                        */
 587/************************************************************************/
 588
 589/* permission checks */
 590static int proc_fd_access_allowed(struct inode *inode)
 591{
 592        struct task_struct *task;
 593        int allowed = 0;
 594        /* Allow access to a task's file descriptors if it is us or we
 595         * may use ptrace attach to the process and find out that
 596         * information.
 597         */
 598        task = get_proc_task(inode);
 599        if (task) {
 600                allowed = ptrace_may_access(task, PTRACE_MODE_READ);
 601                put_task_struct(task);
 602        }
 603        return allowed;
 604}
 605
 606int proc_setattr(struct dentry *dentry, struct iattr *attr)
 607{
 608        int error;
 609        struct inode *inode = dentry->d_inode;
 610
 611        if (attr->ia_valid & ATTR_MODE)
 612                return -EPERM;
 613
 614        error = inode_change_ok(inode, attr);
 615        if (error)
 616                return error;
 617
 618        if ((attr->ia_valid & ATTR_SIZE) &&
 619            attr->ia_size != i_size_read(inode)) {
 620                error = vmtruncate(inode, attr->ia_size);
 621                if (error)
 622                        return error;
 623        }
 624
 625        setattr_copy(inode, attr);
 626        mark_inode_dirty(inode);
 627        return 0;
 628}
 629
 630static const struct inode_operations proc_def_inode_operations = {
 631        .setattr        = proc_setattr,
 632};
 633
 634static int mounts_open_common(struct inode *inode, struct file *file,
 635                              const struct seq_operations *op)
 636{
 637        struct task_struct *task = get_proc_task(inode);
 638        struct nsproxy *nsp;
 639        struct mnt_namespace *ns = NULL;
 640        struct path root;
 641        struct proc_mounts *p;
 642        int ret = -EINVAL;
 643
 644        if (task) {
 645                rcu_read_lock();
 646                nsp = task_nsproxy(task);
 647                if (nsp) {
 648                        ns = nsp->mnt_ns;
 649                        if (ns)
 650                                get_mnt_ns(ns);
 651                }
 652                rcu_read_unlock();
 653                if (ns && get_task_root(task, &root) == 0)
 654                        ret = 0;
 655                put_task_struct(task);
 656        }
 657
 658        if (!ns)
 659                goto err;
 660        if (ret)
 661                goto err_put_ns;
 662
 663        ret = -ENOMEM;
 664        p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
 665        if (!p)
 666                goto err_put_path;
 667
 668        file->private_data = &p->m;
 669        ret = seq_open(file, op);
 670        if (ret)
 671                goto err_free;
 672
 673        p->m.private = p;
 674        p->ns = ns;
 675        p->root = root;
 676        p->event = ns->event;
 677
 678        return 0;
 679
 680 err_free:
 681        kfree(p);
 682 err_put_path:
 683        path_put(&root);
 684 err_put_ns:
 685        put_mnt_ns(ns);
 686 err:
 687        return ret;
 688}
 689
 690static int mounts_release(struct inode *inode, struct file *file)
 691{
 692        struct proc_mounts *p = file->private_data;
 693        path_put(&p->root);
 694        put_mnt_ns(p->ns);
 695        return seq_release(inode, file);
 696}
 697
 698static unsigned mounts_poll(struct file *file, poll_table *wait)
 699{
 700        struct proc_mounts *p = file->private_data;
 701        unsigned res = POLLIN | POLLRDNORM;
 702
 703        poll_wait(file, &p->ns->poll, wait);
 704        if (mnt_had_events(p))
 705                res |= POLLERR | POLLPRI;
 706
 707        return res;
 708}
 709
 710static int mounts_open(struct inode *inode, struct file *file)
 711{
 712        return mounts_open_common(inode, file, &mounts_op);
 713}
 714
 715static const struct file_operations proc_mounts_operations = {
 716        .open           = mounts_open,
 717        .read           = seq_read,
 718        .llseek         = seq_lseek,
 719        .release        = mounts_release,
 720        .poll           = mounts_poll,
 721};
 722
 723static int mountinfo_open(struct inode *inode, struct file *file)
 724{
 725        return mounts_open_common(inode, file, &mountinfo_op);
 726}
 727
 728static const struct file_operations proc_mountinfo_operations = {
 729        .open           = mountinfo_open,
 730        .read           = seq_read,
 731        .llseek         = seq_lseek,
 732        .release        = mounts_release,
 733        .poll           = mounts_poll,
 734};
 735
 736static int mountstats_open(struct inode *inode, struct file *file)
 737{
 738        return mounts_open_common(inode, file, &mountstats_op);
 739}
 740
 741static const struct file_operations proc_mountstats_operations = {
 742        .open           = mountstats_open,
 743        .read           = seq_read,
 744        .llseek         = seq_lseek,
 745        .release        = mounts_release,
 746};
 747
 748#define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 749
 750static ssize_t proc_info_read(struct file * file, char __user * buf,
 751                          size_t count, loff_t *ppos)
 752{
 753        struct inode * inode = file->f_path.dentry->d_inode;
 754        unsigned long page;
 755        ssize_t length;
 756        struct task_struct *task = get_proc_task(inode);
 757
 758        length = -ESRCH;
 759        if (!task)
 760                goto out_no_task;
 761
 762        if (count > PROC_BLOCK_SIZE)
 763                count = PROC_BLOCK_SIZE;
 764
 765        length = -ENOMEM;
 766        if (!(page = __get_free_page(GFP_TEMPORARY)))
 767                goto out;
 768
 769        length = PROC_I(inode)->op.proc_read(task, (char*)page);
 770
 771        if (length >= 0)
 772                length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 773        free_page(page);
 774out:
 775        put_task_struct(task);
 776out_no_task:
 777        return length;
 778}
 779
 780static const struct file_operations proc_info_file_operations = {
 781        .read           = proc_info_read,
 782        .llseek         = generic_file_llseek,
 783};
 784
 785static int proc_single_show(struct seq_file *m, void *v)
 786{
 787        struct inode *inode = m->private;
 788        struct pid_namespace *ns;
 789        struct pid *pid;
 790        struct task_struct *task;
 791        int ret;
 792
 793        ns = inode->i_sb->s_fs_info;
 794        pid = proc_pid(inode);
 795        task = get_pid_task(pid, PIDTYPE_PID);
 796        if (!task)
 797                return -ESRCH;
 798
 799        ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 800
 801        put_task_struct(task);
 802        return ret;
 803}
 804
 805static int proc_single_open(struct inode *inode, struct file *filp)
 806{
 807        return single_open(filp, proc_single_show, inode);
 808}
 809
 810static const struct file_operations proc_single_file_operations = {
 811        .open           = proc_single_open,
 812        .read           = seq_read,
 813        .llseek         = seq_lseek,
 814        .release        = single_release,
 815};
 816
 817static int mem_open(struct inode* inode, struct file* file)
 818{
 819        file->private_data = (void*)((long)current->self_exec_id);
 820        /* OK to pass negative loff_t, we can catch out-of-range */
 821        file->f_mode |= FMODE_UNSIGNED_OFFSET;
 822        return 0;
 823}
 824
 825static ssize_t mem_read(struct file * file, char __user * buf,
 826                        size_t count, loff_t *ppos)
 827{
 828        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 829        char *page;
 830        unsigned long src = *ppos;
 831        int ret = -ESRCH;
 832        struct mm_struct *mm;
 833
 834        if (!task)
 835                goto out_no_task;
 836
 837        ret = -ENOMEM;
 838        page = (char *)__get_free_page(GFP_TEMPORARY);
 839        if (!page)
 840                goto out;
 841
 842        mm = check_mem_permission(task);
 843        ret = PTR_ERR(mm);
 844        if (IS_ERR(mm))
 845                goto out_free;
 846
 847        ret = -EIO;
 848 
 849        if (file->private_data != (void*)((long)current->self_exec_id))
 850                goto out_put;
 851
 852        ret = 0;
 853 
 854        while (count > 0) {
 855                int this_len, retval;
 856
 857                this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 858                retval = access_remote_vm(mm, src, page, this_len, 0);
 859                if (!retval) {
 860                        if (!ret)
 861                                ret = -EIO;
 862                        break;
 863                }
 864
 865                if (copy_to_user(buf, page, retval)) {
 866                        ret = -EFAULT;
 867                        break;
 868                }
 869 
 870                ret += retval;
 871                src += retval;
 872                buf += retval;
 873                count -= retval;
 874        }
 875        *ppos = src;
 876
 877out_put:
 878        mmput(mm);
 879out_free:
 880        free_page((unsigned long) page);
 881out:
 882        put_task_struct(task);
 883out_no_task:
 884        return ret;
 885}
 886
 887static ssize_t mem_write(struct file * file, const char __user *buf,
 888                         size_t count, loff_t *ppos)
 889{
 890        int copied;
 891        char *page;
 892        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 893        unsigned long dst = *ppos;
 894        struct mm_struct *mm;
 895
 896        copied = -ESRCH;
 897        if (!task)
 898                goto out_no_task;
 899
 900        copied = -ENOMEM;
 901        page = (char *)__get_free_page(GFP_TEMPORARY);
 902        if (!page)
 903                goto out_task;
 904
 905        mm = check_mem_permission(task);
 906        copied = PTR_ERR(mm);
 907        if (IS_ERR(mm))
 908                goto out_free;
 909
 910        copied = -EIO;
 911        if (file->private_data != (void *)((long)current->self_exec_id))
 912                goto out_mm;
 913
 914        copied = 0;
 915        while (count > 0) {
 916                int this_len, retval;
 917
 918                this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 919                if (copy_from_user(page, buf, this_len)) {
 920                        copied = -EFAULT;
 921                        break;
 922                }
 923                retval = access_remote_vm(mm, dst, page, this_len, 1);
 924                if (!retval) {
 925                        if (!copied)
 926                                copied = -EIO;
 927                        break;
 928                }
 929                copied += retval;
 930                buf += retval;
 931                dst += retval;
 932                count -= retval;                        
 933        }
 934        *ppos = dst;
 935
 936out_mm:
 937        mmput(mm);
 938out_free:
 939        free_page((unsigned long) page);
 940out_task:
 941        put_task_struct(task);
 942out_no_task:
 943        return copied;
 944}
 945
 946loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 947{
 948        switch (orig) {
 949        case 0:
 950                file->f_pos = offset;
 951                break;
 952        case 1:
 953                file->f_pos += offset;
 954                break;
 955        default:
 956                return -EINVAL;
 957        }
 958        force_successful_syscall_return();
 959        return file->f_pos;
 960}
 961
 962static const struct file_operations proc_mem_operations = {
 963        .llseek         = mem_lseek,
 964        .read           = mem_read,
 965        .write          = mem_write,
 966        .open           = mem_open,
 967};
 968
 969static ssize_t environ_read(struct file *file, char __user *buf,
 970                        size_t count, loff_t *ppos)
 971{
 972        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 973        char *page;
 974        unsigned long src = *ppos;
 975        int ret = -ESRCH;
 976        struct mm_struct *mm;
 977
 978        if (!task)
 979                goto out_no_task;
 980
 981        ret = -ENOMEM;
 982        page = (char *)__get_free_page(GFP_TEMPORARY);
 983        if (!page)
 984                goto out;
 985
 986
 987        mm = mm_for_maps(task);
 988        ret = PTR_ERR(mm);
 989        if (!mm || IS_ERR(mm))
 990                goto out_free;
 991
 992        ret = 0;
 993        while (count > 0) {
 994                int this_len, retval, max_len;
 995
 996                this_len = mm->env_end - (mm->env_start + src);
 997
 998                if (this_len <= 0)
 999                        break;
1000
1001                max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
1002                this_len = (this_len > max_len) ? max_len : this_len;
1003
1004                retval = access_process_vm(task, (mm->env_start + src),
1005                        page, this_len, 0);
1006
1007                if (retval <= 0) {
1008                        ret = retval;
1009                        break;
1010                }
1011
1012                if (copy_to_user(buf, page, retval)) {
1013                        ret = -EFAULT;
1014                        break;
1015                }
1016
1017                ret += retval;
1018                src += retval;
1019                buf += retval;
1020                count -= retval;
1021        }
1022        *ppos = src;
1023
1024        mmput(mm);
1025out_free:
1026        free_page((unsigned long) page);
1027out:
1028        put_task_struct(task);
1029out_no_task:
1030        return ret;
1031}
1032
1033static const struct file_operations proc_environ_operations = {
1034        .read           = environ_read,
1035        .llseek         = generic_file_llseek,
1036};
1037
1038static ssize_t oom_adjust_read(struct file *file, char __user *buf,
1039                                size_t count, loff_t *ppos)
1040{
1041        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1042        char buffer[PROC_NUMBUF];
1043        size_t len;
1044        int oom_adjust = OOM_DISABLE;
1045        unsigned long flags;
1046
1047        if (!task)
1048                return -ESRCH;
1049
1050        if (lock_task_sighand(task, &flags)) {
1051                oom_adjust = task->signal->oom_adj;
1052                unlock_task_sighand(task, &flags);
1053        }
1054
1055        put_task_struct(task);
1056
1057        len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
1058
1059        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1060}
1061
1062static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
1063                                size_t count, loff_t *ppos)
1064{
1065        struct task_struct *task;
1066        char buffer[PROC_NUMBUF];
1067        int oom_adjust;
1068        unsigned long flags;
1069        int err;
1070
1071        memset(buffer, 0, sizeof(buffer));
1072        if (count > sizeof(buffer) - 1)
1073                count = sizeof(buffer) - 1;
1074        if (copy_from_user(buffer, buf, count)) {
1075                err = -EFAULT;
1076                goto out;
1077        }
1078
1079        err = kstrtoint(strstrip(buffer), 0, &oom_adjust);
1080        if (err)
1081                goto out;
1082        if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
1083             oom_adjust != OOM_DISABLE) {
1084                err = -EINVAL;
1085                goto out;
1086        }
1087
1088        task = get_proc_task(file->f_path.dentry->d_inode);
1089        if (!task) {
1090                err = -ESRCH;
1091                goto out;
1092        }
1093
1094        task_lock(task);
1095        if (!task->mm) {
1096                err = -EINVAL;
1097                goto err_task_lock;
1098        }
1099
1100        if (!lock_task_sighand(task, &flags)) {
1101                err = -ESRCH;
1102                goto err_task_lock;
1103        }
1104
1105        if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
1106                err = -EACCES;
1107                goto err_sighand;
1108        }
1109
1110        if (oom_adjust != task->signal->oom_adj) {
1111                if (oom_adjust == OOM_DISABLE)
1112                        atomic_inc(&task->mm->oom_disable_count);
1113                if (task->signal->oom_adj == OOM_DISABLE)
1114                        atomic_dec(&task->mm->oom_disable_count);
1115        }
1116
1117        /*
1118         * Warn that /proc/pid/oom_adj is deprecated, see
1119         * Documentation/feature-removal-schedule.txt.
1120         */
1121        printk_once(KERN_WARNING "%s (%d): /proc/%d/oom_adj is deprecated, "
1122                        "please use /proc/%d/oom_score_adj instead.\n",
1123                        current->comm, task_pid_nr(current),
1124                        task_pid_nr(task), task_pid_nr(task));
1125        task->signal->oom_adj = oom_adjust;
1126        /*
1127         * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1128         * value is always attainable.
1129         */
1130        if (task->signal->oom_adj == OOM_ADJUST_MAX)
1131                task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX;
1132        else
1133                task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
1134                                                                -OOM_DISABLE;
1135err_sighand:
1136        unlock_task_sighand(task, &flags);
1137err_task_lock:
1138        task_unlock(task);
1139        put_task_struct(task);
1140out:
1141        return err < 0 ? err : count;
1142}
1143
1144static const struct file_operations proc_oom_adjust_operations = {
1145        .read           = oom_adjust_read,
1146        .write          = oom_adjust_write,
1147        .llseek         = generic_file_llseek,
1148};
1149
1150static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1151                                        size_t count, loff_t *ppos)
1152{
1153        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1154        char buffer[PROC_NUMBUF];
1155        int oom_score_adj = OOM_SCORE_ADJ_MIN;
1156        unsigned long flags;
1157        size_t len;
1158
1159        if (!task)
1160                return -ESRCH;
1161        if (lock_task_sighand(task, &flags)) {
1162                oom_score_adj = task->signal->oom_score_adj;
1163                unlock_task_sighand(task, &flags);
1164        }
1165        put_task_struct(task);
1166        len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj);
1167        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1168}
1169
1170static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1171                                        size_t count, loff_t *ppos)
1172{
1173        struct task_struct *task;
1174        char buffer[PROC_NUMBUF];
1175        unsigned long flags;
1176        int oom_score_adj;
1177        int err;
1178
1179        memset(buffer, 0, sizeof(buffer));
1180        if (count > sizeof(buffer) - 1)
1181                count = sizeof(buffer) - 1;
1182        if (copy_from_user(buffer, buf, count)) {
1183                err = -EFAULT;
1184                goto out;
1185        }
1186
1187        err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1188        if (err)
1189                goto out;
1190        if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1191                        oom_score_adj > OOM_SCORE_ADJ_MAX) {
1192                err = -EINVAL;
1193                goto out;
1194        }
1195
1196        task = get_proc_task(file->f_path.dentry->d_inode);
1197        if (!task) {
1198                err = -ESRCH;
1199                goto out;
1200        }
1201
1202        task_lock(task);
1203        if (!task->mm) {
1204                err = -EINVAL;
1205                goto err_task_lock;
1206        }
1207
1208        if (!lock_task_sighand(task, &flags)) {
1209                err = -ESRCH;
1210                goto err_task_lock;
1211        }
1212
1213        if (oom_score_adj < task->signal->oom_score_adj_min &&
1214                        !capable(CAP_SYS_RESOURCE)) {
1215                err = -EACCES;
1216                goto err_sighand;
1217        }
1218
1219        if (oom_score_adj != task->signal->oom_score_adj) {
1220                if (oom_score_adj == OOM_SCORE_ADJ_MIN)
1221                        atomic_inc(&task->mm->oom_disable_count);
1222                if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1223                        atomic_dec(&task->mm->oom_disable_count);
1224        }
1225        task->signal->oom_score_adj = oom_score_adj;
1226        if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1227                task->signal->oom_score_adj_min = oom_score_adj;
1228        /*
1229         * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
1230         * always attainable.
1231         */
1232        if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1233                task->signal->oom_adj = OOM_DISABLE;
1234        else
1235                task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
1236                                                        OOM_SCORE_ADJ_MAX;
1237err_sighand:
1238        unlock_task_sighand(task, &flags);
1239err_task_lock:
1240        task_unlock(task);
1241        put_task_struct(task);
1242out:
1243        return err < 0 ? err : count;
1244}
1245
1246static const struct file_operations proc_oom_score_adj_operations = {
1247        .read           = oom_score_adj_read,
1248        .write          = oom_score_adj_write,
1249        .llseek         = default_llseek,
1250};
1251
1252#ifdef CONFIG_AUDITSYSCALL
1253#define TMPBUFLEN 21
1254static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1255                                  size_t count, loff_t *ppos)
1256{
1257        struct inode * inode = file->f_path.dentry->d_inode;
1258        struct task_struct *task = get_proc_task(inode);
1259        ssize_t length;
1260        char tmpbuf[TMPBUFLEN];
1261
1262        if (!task)
1263                return -ESRCH;
1264        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1265                                audit_get_loginuid(task));
1266        put_task_struct(task);
1267        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1268}
1269
1270static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1271                                   size_t count, loff_t *ppos)
1272{
1273        struct inode * inode = file->f_path.dentry->d_inode;
1274        char *page, *tmp;
1275        ssize_t length;
1276        uid_t loginuid;
1277
1278        if (!capable(CAP_AUDIT_CONTROL))
1279                return -EPERM;
1280
1281        rcu_read_lock();
1282        if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1283                rcu_read_unlock();
1284                return -EPERM;
1285        }
1286        rcu_read_unlock();
1287
1288        if (count >= PAGE_SIZE)
1289                count = PAGE_SIZE - 1;
1290
1291        if (*ppos != 0) {
1292                /* No partial writes. */
1293                return -EINVAL;
1294        }
1295        page = (char*)__get_free_page(GFP_TEMPORARY);
1296        if (!page)
1297                return -ENOMEM;
1298        length = -EFAULT;
1299        if (copy_from_user(page, buf, count))
1300                goto out_free_page;
1301
1302        page[count] = '\0';
1303        loginuid = simple_strtoul(page, &tmp, 10);
1304        if (tmp == page) {
1305                length = -EINVAL;
1306                goto out_free_page;
1307
1308        }
1309        length = audit_set_loginuid(current, loginuid);
1310        if (likely(length == 0))
1311                length = count;
1312
1313out_free_page:
1314        free_page((unsigned long) page);
1315        return length;
1316}
1317
1318static const struct file_operations proc_loginuid_operations = {
1319        .read           = proc_loginuid_read,
1320        .write          = proc_loginuid_write,
1321        .llseek         = generic_file_llseek,
1322};
1323
1324static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1325                                  size_t count, loff_t *ppos)
1326{
1327        struct inode * inode = file->f_path.dentry->d_inode;
1328        struct task_struct *task = get_proc_task(inode);
1329        ssize_t length;
1330        char tmpbuf[TMPBUFLEN];
1331
1332        if (!task)
1333                return -ESRCH;
1334        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1335                                audit_get_sessionid(task));
1336        put_task_struct(task);
1337        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1338}
1339
1340static const struct file_operations proc_sessionid_operations = {
1341        .read           = proc_sessionid_read,
1342        .llseek         = generic_file_llseek,
1343};
1344#endif
1345
1346#ifdef CONFIG_FAULT_INJECTION
1347static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1348                                      size_t count, loff_t *ppos)
1349{
1350        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1351        char buffer[PROC_NUMBUF];
1352        size_t len;
1353        int make_it_fail;
1354
1355        if (!task)
1356                return -ESRCH;
1357        make_it_fail = task->make_it_fail;
1358        put_task_struct(task);
1359
1360        len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1361
1362        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1363}
1364
1365static ssize_t proc_fault_inject_write(struct file * file,
1366                        const char __user * buf, size_t count, loff_t *ppos)
1367{
1368        struct task_struct *task;
1369        char buffer[PROC_NUMBUF], *end;
1370        int make_it_fail;
1371
1372        if (!capable(CAP_SYS_RESOURCE))
1373                return -EPERM;
1374        memset(buffer, 0, sizeof(buffer));
1375        if (count > sizeof(buffer) - 1)
1376                count = sizeof(buffer) - 1;
1377        if (copy_from_user(buffer, buf, count))
1378                return -EFAULT;
1379        make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
1380        if (*end)
1381                return -EINVAL;
1382        task = get_proc_task(file->f_dentry->d_inode);
1383        if (!task)
1384                return -ESRCH;
1385        task->make_it_fail = make_it_fail;
1386        put_task_struct(task);
1387
1388        return count;
1389}
1390
1391static const struct file_operations proc_fault_inject_operations = {
1392        .read           = proc_fault_inject_read,
1393        .write          = proc_fault_inject_write,
1394        .llseek         = generic_file_llseek,
1395};
1396#endif
1397
1398
1399#ifdef CONFIG_SCHED_DEBUG
1400/*
1401 * Print out various scheduling related per-task fields:
1402 */
1403static int sched_show(struct seq_file *m, void *v)
1404{
1405        struct inode *inode = m->private;
1406        struct task_struct *p;
1407
1408        p = get_proc_task(inode);
1409        if (!p)
1410                return -ESRCH;
1411        proc_sched_show_task(p, m);
1412
1413        put_task_struct(p);
1414
1415        return 0;
1416}
1417
1418static ssize_t
1419sched_write(struct file *file, const char __user *buf,
1420            size_t count, loff_t *offset)
1421{
1422        struct inode *inode = file->f_path.dentry->d_inode;
1423        struct task_struct *p;
1424
1425        p = get_proc_task(inode);
1426        if (!p)
1427                return -ESRCH;
1428        proc_sched_set_task(p);
1429
1430        put_task_struct(p);
1431
1432        return count;
1433}
1434
1435static int sched_open(struct inode *inode, struct file *filp)
1436{
1437        return single_open(filp, sched_show, inode);
1438}
1439
1440static const struct file_operations proc_pid_sched_operations = {
1441        .open           = sched_open,
1442        .read           = seq_read,
1443        .write          = sched_write,
1444        .llseek         = seq_lseek,
1445        .release        = single_release,
1446};
1447
1448#endif
1449
1450#ifdef CONFIG_SCHED_AUTOGROUP
1451/*
1452 * Print out autogroup related information:
1453 */
1454static int sched_autogroup_show(struct seq_file *m, void *v)
1455{
1456        struct inode *inode = m->private;
1457        struct task_struct *p;
1458
1459        p = get_proc_task(inode);
1460        if (!p)
1461                return -ESRCH;
1462        proc_sched_autogroup_show_task(p, m);
1463
1464        put_task_struct(p);
1465
1466        return 0;
1467}
1468
1469static ssize_t
1470sched_autogroup_write(struct file *file, const char __user *buf,
1471            size_t count, loff_t *offset)
1472{
1473        struct inode *inode = file->f_path.dentry->d_inode;
1474        struct task_struct *p;
1475        char buffer[PROC_NUMBUF];
1476        int nice;
1477        int err;
1478
1479        memset(buffer, 0, sizeof(buffer));
1480        if (count > sizeof(buffer) - 1)
1481                count = sizeof(buffer) - 1;
1482        if (copy_from_user(buffer, buf, count))
1483                return -EFAULT;
1484
1485        err = kstrtoint(strstrip(buffer), 0, &nice);
1486        if (err < 0)
1487                return err;
1488
1489        p = get_proc_task(inode);
1490        if (!p)
1491                return -ESRCH;
1492
1493        err = nice;
1494        err = proc_sched_autogroup_set_nice(p, &err);
1495        if (err)
1496                count = err;
1497
1498        put_task_struct(p);
1499
1500        return count;
1501}
1502
1503static int sched_autogroup_open(struct inode *inode, struct file *filp)
1504{
1505        int ret;
1506
1507        ret = single_open(filp, sched_autogroup_show, NULL);
1508        if (!ret) {
1509                struct seq_file *m = filp->private_data;
1510
1511                m->private = inode;
1512        }
1513        return ret;
1514}
1515
1516static const struct file_operations proc_pid_sched_autogroup_operations = {
1517        .open           = sched_autogroup_open,
1518        .read           = seq_read,
1519        .write          = sched_autogroup_write,
1520        .llseek         = seq_lseek,
1521        .release        = single_release,
1522};
1523
1524#endif /* CONFIG_SCHED_AUTOGROUP */
1525
1526static ssize_t comm_write(struct file *file, const char __user *buf,
1527                                size_t count, loff_t *offset)
1528{
1529        struct inode *inode = file->f_path.dentry->d_inode;
1530        struct task_struct *p;
1531        char buffer[TASK_COMM_LEN];
1532
1533        memset(buffer, 0, sizeof(buffer));
1534        if (count > sizeof(buffer) - 1)
1535                count = sizeof(buffer) - 1;
1536        if (copy_from_user(buffer, buf, count))
1537                return -EFAULT;
1538
1539        p = get_proc_task(inode);
1540        if (!p)
1541                return -ESRCH;
1542
1543        if (same_thread_group(current, p))
1544                set_task_comm(p, buffer);
1545        else
1546                count = -EINVAL;
1547
1548        put_task_struct(p);
1549
1550        return count;
1551}
1552
1553static int comm_show(struct seq_file *m, void *v)
1554{
1555        struct inode *inode = m->private;
1556        struct task_struct *p;
1557
1558        p = get_proc_task(inode);
1559        if (!p)
1560                return -ESRCH;
1561
1562        task_lock(p);
1563        seq_printf(m, "%s\n", p->comm);
1564        task_unlock(p);
1565
1566        put_task_struct(p);
1567
1568        return 0;
1569}
1570
1571static int comm_open(struct inode *inode, struct file *filp)
1572{
1573        return single_open(filp, comm_show, inode);
1574}
1575
1576static const struct file_operations proc_pid_set_comm_operations = {
1577        .open           = comm_open,
1578        .read           = seq_read,
1579        .write          = comm_write,
1580        .llseek         = seq_lseek,
1581        .release        = single_release,
1582};
1583
1584static int proc_exe_link(struct inode *inode, struct path *exe_path)
1585{
1586        struct task_struct *task;
1587        struct mm_struct *mm;
1588        struct file *exe_file;
1589
1590        task = get_proc_task(inode);
1591        if (!task)
1592                return -ENOENT;
1593        mm = get_task_mm(task);
1594        put_task_struct(task);
1595        if (!mm)
1596                return -ENOENT;
1597        exe_file = get_mm_exe_file(mm);
1598        mmput(mm);
1599        if (exe_file) {
1600                *exe_path = exe_file->f_path;
1601                path_get(&exe_file->f_path);
1602                fput(exe_file);
1603                return 0;
1604        } else
1605                return -ENOENT;
1606}
1607
1608static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1609{
1610        struct inode *inode = dentry->d_inode;
1611        int error = -EACCES;
1612
1613        /* We don't need a base pointer in the /proc filesystem */
1614        path_put(&nd->path);
1615
1616        /* Are we allowed to snoop on the tasks file descriptors? */
1617        if (!proc_fd_access_allowed(inode))
1618                goto out;
1619
1620        error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1621out:
1622        return ERR_PTR(error);
1623}
1624
1625static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1626{
1627        char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1628        char *pathname;
1629        int len;
1630
1631        if (!tmp)
1632                return -ENOMEM;
1633
1634        pathname = d_path(path, tmp, PAGE_SIZE);
1635        len = PTR_ERR(pathname);
1636        if (IS_ERR(pathname))
1637                goto out;
1638        len = tmp + PAGE_SIZE - 1 - pathname;
1639
1640        if (len > buflen)
1641                len = buflen;
1642        if (copy_to_user(buffer, pathname, len))
1643                len = -EFAULT;
1644 out:
1645        free_page((unsigned long)tmp);
1646        return len;
1647}
1648
1649static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1650{
1651        int error = -EACCES;
1652        struct inode *inode = dentry->d_inode;
1653        struct path path;
1654
1655        /* Are we allowed to snoop on the tasks file descriptors? */
1656        if (!proc_fd_access_allowed(inode))
1657                goto out;
1658
1659        error = PROC_I(inode)->op.proc_get_link(inode, &path);
1660        if (error)
1661                goto out;
1662
1663        error = do_proc_readlink(&path, buffer, buflen);
1664        path_put(&path);
1665out:
1666        return error;
1667}
1668
1669static const struct inode_operations proc_pid_link_inode_operations = {
1670        .readlink       = proc_pid_readlink,
1671        .follow_link    = proc_pid_follow_link,
1672        .setattr        = proc_setattr,
1673};
1674
1675
1676/* building an inode */
1677
1678static int task_dumpable(struct task_struct *task)
1679{
1680        int dumpable = 0;
1681        struct mm_struct *mm;
1682
1683        task_lock(task);
1684        mm = task->mm;
1685        if (mm)
1686                dumpable = get_dumpable(mm);
1687        task_unlock(task);
1688        if(dumpable == 1)
1689                return 1;
1690        return 0;
1691}
1692
1693struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1694{
1695        struct inode * inode;
1696        struct proc_inode *ei;
1697        const struct cred *cred;
1698
1699        /* We need a new inode */
1700
1701        inode = new_inode(sb);
1702        if (!inode)
1703                goto out;
1704
1705        /* Common stuff */
1706        ei = PROC_I(inode);
1707        inode->i_ino = get_next_ino();
1708        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1709        inode->i_op = &proc_def_inode_operations;
1710
1711        /*
1712         * grab the reference to task.
1713         */
1714        ei->pid = get_task_pid(task, PIDTYPE_PID);
1715        if (!ei->pid)
1716                goto out_unlock;
1717
1718        if (task_dumpable(task)) {
1719                rcu_read_lock();
1720                cred = __task_cred(task);
1721                inode->i_uid = cred->euid;
1722                inode->i_gid = cred->egid;
1723                rcu_read_unlock();
1724        }
1725        security_task_to_inode(task, inode);
1726
1727out:
1728        return inode;
1729
1730out_unlock:
1731        iput(inode);
1732        return NULL;
1733}
1734
1735int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1736{
1737        struct inode *inode = dentry->d_inode;
1738        struct task_struct *task;
1739        const struct cred *cred;
1740
1741        generic_fillattr(inode, stat);
1742
1743        rcu_read_lock();
1744        stat->uid = 0;
1745        stat->gid = 0;
1746        task = pid_task(proc_pid(inode), PIDTYPE_PID);
1747        if (task) {
1748                if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1749                    task_dumpable(task)) {
1750                        cred = __task_cred(task);
1751                        stat->uid = cred->euid;
1752                        stat->gid = cred->egid;
1753                }
1754        }
1755        rcu_read_unlock();
1756        return 0;
1757}
1758
1759/* dentry stuff */
1760
1761/*
1762 *      Exceptional case: normally we are not allowed to unhash a busy
1763 * directory. In this case, however, we can do it - no aliasing problems
1764 * due to the way we treat inodes.
1765 *
1766 * Rewrite the inode's ownerships here because the owning task may have
1767 * performed a setuid(), etc.
1768 *
1769 * Before the /proc/pid/status file was created the only way to read
1770 * the effective uid of a /process was to stat /proc/pid.  Reading
1771 * /proc/pid/status is slow enough that procps and other packages
1772 * kept stating /proc/pid.  To keep the rules in /proc simple I have
1773 * made this apply to all per process world readable and executable
1774 * directories.
1775 */
1776int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1777{
1778        struct inode *inode;
1779        struct task_struct *task;
1780        const struct cred *cred;
1781
1782        if (nd && nd->flags & LOOKUP_RCU)
1783                return -ECHILD;
1784
1785        inode = dentry->d_inode;
1786        task = get_proc_task(inode);
1787
1788        if (task) {
1789                if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1790                    task_dumpable(task)) {
1791                        rcu_read_lock();
1792                        cred = __task_cred(task);
1793                        inode->i_uid = cred->euid;
1794                        inode->i_gid = cred->egid;
1795                        rcu_read_unlock();
1796                } else {
1797                        inode->i_uid = 0;
1798                        inode->i_gid = 0;
1799                }
1800                inode->i_mode &= ~(S_ISUID | S_ISGID);
1801                security_task_to_inode(task, inode);
1802                put_task_struct(task);
1803                return 1;
1804        }
1805        d_drop(dentry);
1806        return 0;
1807}
1808
1809static int pid_delete_dentry(const struct dentry * dentry)
1810{
1811        /* Is the task we represent dead?
1812         * If so, then don't put the dentry on the lru list,
1813         * kill it immediately.
1814         */
1815        return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1816}
1817
1818const struct dentry_operations pid_dentry_operations =
1819{
1820        .d_revalidate   = pid_revalidate,
1821        .d_delete       = pid_delete_dentry,
1822};
1823
1824/* Lookups */
1825
1826/*
1827 * Fill a directory entry.
1828 *
1829 * If possible create the dcache entry and derive our inode number and
1830 * file type from dcache entry.
1831 *
1832 * Since all of the proc inode numbers are dynamically generated, the inode
1833 * numbers do not exist until the inode is cache.  This means creating the
1834 * the dcache entry in readdir is necessary to keep the inode numbers
1835 * reported by readdir in sync with the inode numbers reported
1836 * by stat.
1837 */
1838int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1839        const char *name, int len,
1840        instantiate_t instantiate, struct task_struct *task, const void *ptr)
1841{
1842        struct dentry *child, *dir = filp->f_path.dentry;
1843        struct inode *inode;
1844        struct qstr qname;
1845        ino_t ino = 0;
1846        unsigned type = DT_UNKNOWN;
1847
1848        qname.name = name;
1849        qname.len  = len;
1850        qname.hash = full_name_hash(name, len);
1851
1852        child = d_lookup(dir, &qname);
1853        if (!child) {
1854                struct dentry *new;
1855                new = d_alloc(dir, &qname);
1856                if (new) {
1857                        child = instantiate(dir->d_inode, new, task, ptr);
1858                        if (child)
1859                                dput(new);
1860                        else
1861                                child = new;
1862                }
1863        }
1864        if (!child || IS_ERR(child) || !child->d_inode)
1865                goto end_instantiate;
1866        inode = child->d_inode;
1867        if (inode) {
1868                ino = inode->i_ino;
1869                type = inode->i_mode >> 12;
1870        }
1871        dput(child);
1872end_instantiate:
1873        if (!ino)
1874                ino = find_inode_number(dir, &qname);
1875        if (!ino)
1876                ino = 1;
1877        return filldir(dirent, name, len, filp->f_pos, ino, type);
1878}
1879
1880static unsigned name_to_int(struct dentry *dentry)
1881{
1882        const char *name = dentry->d_name.name;
1883        int len = dentry->d_name.len;
1884        unsigned n = 0;
1885
1886        if (len > 1 && *name == '0')
1887                goto out;
1888        while (len-- > 0) {
1889                unsigned c = *name++ - '0';
1890                if (c > 9)
1891                        goto out;
1892                if (n >= (~0U-9)/10)
1893                        goto out;
1894                n *= 10;
1895                n += c;
1896        }
1897        return n;
1898out:
1899        return ~0U;
1900}
1901
1902#define PROC_FDINFO_MAX 64
1903
1904static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1905{
1906        struct task_struct *task = get_proc_task(inode);
1907        struct files_struct *files = NULL;
1908        struct file *file;
1909        int fd = proc_fd(inode);
1910
1911        if (task) {
1912                files = get_files_struct(task);
1913                put_task_struct(task);
1914        }
1915        if (files) {
1916                /*
1917                 * We are not taking a ref to the file structure, so we must
1918                 * hold ->file_lock.
1919                 */
1920                spin_lock(&files->file_lock);
1921                file = fcheck_files(files, fd);
1922                if (file) {
1923                        if (path) {
1924                                *path = file->f_path;
1925                                path_get(&file->f_path);
1926                        }
1927                        if (info)
1928                                snprintf(info, PROC_FDINFO_MAX,
1929                                         "pos:\t%lli\n"
1930                                         "flags:\t0%o\n",
1931                                         (long long) file->f_pos,
1932                                         file->f_flags);
1933                        spin_unlock(&files->file_lock);
1934                        put_files_struct(files);
1935                        return 0;
1936                }
1937                spin_unlock(&files->file_lock);
1938                put_files_struct(files);
1939        }
1940        return -ENOENT;
1941}
1942
1943static int proc_fd_link(struct inode *inode, struct path *path)
1944{
1945        return proc_fd_info(inode, path, NULL);
1946}
1947
1948static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1949{
1950        struct inode *inode;
1951        struct task_struct *task;
1952        int fd;
1953        struct files_struct *files;
1954        const struct cred *cred;
1955
1956        if (nd && nd->flags & LOOKUP_RCU)
1957                return -ECHILD;
1958
1959        inode = dentry->d_inode;
1960        task = get_proc_task(inode);
1961        fd = proc_fd(inode);
1962
1963        if (task) {
1964                files = get_files_struct(task);
1965                if (files) {
1966                        rcu_read_lock();
1967                        if (fcheck_files(files, fd)) {
1968                                rcu_read_unlock();
1969                                put_files_struct(files);
1970                                if (task_dumpable(task)) {
1971                                        rcu_read_lock();
1972                                        cred = __task_cred(task);
1973                                        inode->i_uid = cred->euid;
1974                                        inode->i_gid = cred->egid;
1975                                        rcu_read_unlock();
1976                                } else {
1977                                        inode->i_uid = 0;
1978                                        inode->i_gid = 0;
1979                                }
1980                                inode->i_mode &= ~(S_ISUID | S_ISGID);
1981                                security_task_to_inode(task, inode);
1982                                put_task_struct(task);
1983                                return 1;
1984                        }
1985                        rcu_read_unlock();
1986                        put_files_struct(files);
1987                }
1988                put_task_struct(task);
1989        }
1990        d_drop(dentry);
1991        return 0;
1992}
1993
1994static const struct dentry_operations tid_fd_dentry_operations =
1995{
1996        .d_revalidate   = tid_fd_revalidate,
1997        .d_delete       = pid_delete_dentry,
1998};
1999
2000static struct dentry *proc_fd_instantiate(struct inode *dir,
2001        struct dentry *dentry, struct task_struct *task, const void *ptr)
2002{
2003        unsigned fd = *(const unsigned *)ptr;
2004        struct file *file;
2005        struct files_struct *files;
2006        struct inode *inode;
2007        struct proc_inode *ei;
2008        struct dentry *error = ERR_PTR(-ENOENT);
2009
2010        inode = proc_pid_make_inode(dir->i_sb, task);
2011        if (!inode)
2012                goto out;
2013        ei = PROC_I(inode);
2014        ei->fd = fd;
2015        files = get_files_struct(task);
2016        if (!files)
2017                goto out_iput;
2018        inode->i_mode = S_IFLNK;
2019
2020        /*
2021         * We are not taking a ref to the file structure, so we must
2022         * hold ->file_lock.
2023         */
2024        spin_lock(&files->file_lock);
2025        file = fcheck_files(files, fd);
2026        if (!file)
2027                goto out_unlock;
2028        if (file->f_mode & FMODE_READ)
2029                inode->i_mode |= S_IRUSR | S_IXUSR;
2030        if (file->f_mode & FMODE_WRITE)
2031                inode->i_mode |= S_IWUSR | S_IXUSR;
2032        spin_unlock(&files->file_lock);
2033        put_files_struct(files);
2034
2035        inode->i_op = &proc_pid_link_inode_operations;
2036        inode->i_size = 64;
2037        ei->op.proc_get_link = proc_fd_link;
2038        d_set_d_op(dentry, &tid_fd_dentry_operations);
2039        d_add(dentry, inode);
2040        /* Close the race of the process dying before we return the dentry */
2041        if (tid_fd_revalidate(dentry, NULL))
2042                error = NULL;
2043
2044 out:
2045        return error;
2046out_unlock:
2047        spin_unlock(&files->file_lock);
2048        put_files_struct(files);
2049out_iput:
2050        iput(inode);
2051        goto out;
2052}
2053
2054static struct dentry *proc_lookupfd_common(struct inode *dir,
2055                                           struct dentry *dentry,
2056                                           instantiate_t instantiate)
2057{
2058        struct task_struct *task = get_proc_task(dir);
2059        unsigned fd = name_to_int(dentry);
2060        struct dentry *result = ERR_PTR(-ENOENT);
2061
2062        if (!task)
2063                goto out_no_task;
2064        if (fd == ~0U)
2065                goto out;
2066
2067        result = instantiate(dir, dentry, task, &fd);
2068out:
2069        put_task_struct(task);
2070out_no_task:
2071        return result;
2072}
2073
2074static int proc_readfd_common(struct file * filp, void * dirent,
2075                              filldir_t filldir, instantiate_t instantiate)
2076{
2077        struct dentry *dentry = filp->f_path.dentry;
2078        struct inode *inode = dentry->d_inode;
2079        struct task_struct *p = get_proc_task(inode);
2080        unsigned int fd, ino;
2081        int retval;
2082        struct files_struct * files;
2083
2084        retval = -ENOENT;
2085        if (!p)
2086                goto out_no_task;
2087        retval = 0;
2088
2089        fd = filp->f_pos;
2090        switch (fd) {
2091                case 0:
2092                        if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
2093                                goto out;
2094                        filp->f_pos++;
2095                case 1:
2096                        ino = parent_ino(dentry);
2097                        if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
2098                                goto out;
2099                        filp->f_pos++;
2100                default:
2101                        files = get_files_struct(p);
2102                        if (!files)
2103                                goto out;
2104                        rcu_read_lock();
2105                        for (fd = filp->f_pos-2;
2106                             fd < files_fdtable(files)->max_fds;
2107                             fd++, filp->f_pos++) {
2108                                char name[PROC_NUMBUF];
2109                                int len;
2110
2111                                if (!fcheck_files(files, fd))
2112                                        continue;
2113                                rcu_read_unlock();
2114
2115                                len = snprintf(name, sizeof(name), "%d", fd);
2116                                if (proc_fill_cache(filp, dirent, filldir,
2117                                                    name, len, instantiate,
2118                                                    p, &fd) < 0) {
2119                                        rcu_read_lock();
2120                                        break;
2121                                }
2122                                rcu_read_lock();
2123                        }
2124                        rcu_read_unlock();
2125                        put_files_struct(files);
2126        }
2127out:
2128        put_task_struct(p);
2129out_no_task:
2130        return retval;
2131}
2132
2133static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
2134                                    struct nameidata *nd)
2135{
2136        return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
2137}
2138
2139static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
2140{
2141        return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
2142}
2143
2144static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
2145                                      size_t len, loff_t *ppos)
2146{
2147        char tmp[PROC_FDINFO_MAX];
2148        int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
2149        if (!err)
2150                err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
2151        return err;
2152}
2153
2154static const struct file_operations proc_fdinfo_file_operations = {
2155        .open           = nonseekable_open,
2156        .read           = proc_fdinfo_read,
2157        .llseek         = no_llseek,
2158};
2159
2160static const struct file_operations proc_fd_operations = {
2161        .read           = generic_read_dir,
2162        .readdir        = proc_readfd,
2163        .llseek         = default_llseek,
2164};
2165
2166/*
2167 * /proc/pid/fd needs a special permission handler so that a process can still
2168 * access /proc/self/fd after it has executed a setuid().
2169 */
2170static int proc_fd_permission(struct inode *inode, int mask, unsigned int flags)
2171{
2172        int rv = generic_permission(inode, mask, flags, NULL);
2173        if (rv == 0)
2174                return 0;
2175        if (task_pid(current) == proc_pid(inode))
2176                rv = 0;
2177        return rv;
2178}
2179
2180/*
2181 * proc directories can do almost nothing..
2182 */
2183static const struct inode_operations proc_fd_inode_operations = {
2184        .lookup         = proc_lookupfd,
2185        .permission     = proc_fd_permission,
2186        .setattr        = proc_setattr,
2187};
2188
2189static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
2190        struct dentry *dentry, struct task_struct *task, const void *ptr)
2191{
2192        unsigned fd = *(unsigned *)ptr;
2193        struct inode *inode;
2194        struct proc_inode *ei;
2195        struct dentry *error = ERR_PTR(-ENOENT);
2196
2197        inode = proc_pid_make_inode(dir->i_sb, task);
2198        if (!inode)
2199                goto out;
2200        ei = PROC_I(inode);
2201        ei->fd = fd;
2202        inode->i_mode = S_IFREG | S_IRUSR;
2203        inode->i_fop = &proc_fdinfo_file_operations;
2204        d_set_d_op(dentry, &tid_fd_dentry_operations);
2205        d_add(dentry, inode);
2206        /* Close the race of the process dying before we return the dentry */
2207        if (tid_fd_revalidate(dentry, NULL))
2208                error = NULL;
2209
2210 out:
2211        return error;
2212}
2213
2214static struct dentry *proc_lookupfdinfo(struct inode *dir,
2215                                        struct dentry *dentry,
2216                                        struct nameidata *nd)
2217{
2218        return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
2219}
2220
2221static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
2222{
2223        return proc_readfd_common(filp, dirent, filldir,
2224                                  proc_fdinfo_instantiate);
2225}
2226
2227static const struct file_operations proc_fdinfo_operations = {
2228        .read           = generic_read_dir,
2229        .readdir        = proc_readfdinfo,
2230        .llseek         = default_llseek,
2231};
2232
2233/*
2234 * proc directories can do almost nothing..
2235 */
2236static const struct inode_operations proc_fdinfo_inode_operations = {
2237        .lookup         = proc_lookupfdinfo,
2238        .setattr        = proc_setattr,
2239};
2240
2241
2242static struct dentry *proc_pident_instantiate(struct inode *dir,
2243        struct dentry *dentry, struct task_struct *task, const void *ptr)
2244{
2245        const struct pid_entry *p = ptr;
2246        struct inode *inode;
2247        struct proc_inode *ei;
2248        struct dentry *error = ERR_PTR(-ENOENT);
2249
2250        inode = proc_pid_make_inode(dir->i_sb, task);
2251        if (!inode)
2252                goto out;
2253
2254        ei = PROC_I(inode);
2255        inode->i_mode = p->mode;
2256        if (S_ISDIR(inode->i_mode))
2257                inode->i_nlink = 2;     /* Use getattr to fix if necessary */
2258        if (p->iop)
2259                inode->i_op = p->iop;
2260        if (p->fop)
2261                inode->i_fop = p->fop;
2262        ei->op = p->op;
2263        d_set_d_op(dentry, &pid_dentry_operations);
2264        d_add(dentry, inode);
2265        /* Close the race of the process dying before we return the dentry */
2266        if (pid_revalidate(dentry, NULL))
2267                error = NULL;
2268out:
2269        return error;
2270}
2271
2272static struct dentry *proc_pident_lookup(struct inode *dir, 
2273                                         struct dentry *dentry,
2274                                         const struct pid_entry *ents,
2275                                         unsigned int nents)
2276{
2277        struct dentry *error;
2278        struct task_struct *task = get_proc_task(dir);
2279        const struct pid_entry *p, *last;
2280
2281        error = ERR_PTR(-ENOENT);
2282
2283        if (!task)
2284                goto out_no_task;
2285
2286        /*
2287         * Yes, it does not scale. And it should not. Don't add
2288         * new entries into /proc/<tgid>/ without very good reasons.
2289         */
2290        last = &ents[nents - 1];
2291        for (p = ents; p <= last; p++) {
2292                if (p->len != dentry->d_name.len)
2293                        continue;
2294                if (!memcmp(dentry->d_name.name, p->name, p->len))
2295                        break;
2296        }
2297        if (p > last)
2298                goto out;
2299
2300        error = proc_pident_instantiate(dir, dentry, task, p);
2301out:
2302        put_task_struct(task);
2303out_no_task:
2304        return error;
2305}
2306
2307static int proc_pident_fill_cache(struct file *filp, void *dirent,
2308        filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2309{
2310        return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2311                                proc_pident_instantiate, task, p);
2312}
2313
2314static int proc_pident_readdir(struct file *filp,
2315                void *dirent, filldir_t filldir,
2316                const struct pid_entry *ents, unsigned int nents)
2317{
2318        int i;
2319        struct dentry *dentry = filp->f_path.dentry;
2320        struct inode *inode = dentry->d_inode;
2321        struct task_struct *task = get_proc_task(inode);
2322        const struct pid_entry *p, *last;
2323        ino_t ino;
2324        int ret;
2325
2326        ret = -ENOENT;
2327        if (!task)
2328                goto out_no_task;
2329
2330        ret = 0;
2331        i = filp->f_pos;
2332        switch (i) {
2333        case 0:
2334                ino = inode->i_ino;
2335                if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2336                        goto out;
2337                i++;
2338                filp->f_pos++;
2339                /* fall through */
2340        case 1:
2341                ino = parent_ino(dentry);
2342                if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2343                        goto out;
2344                i++;
2345                filp->f_pos++;
2346                /* fall through */
2347        default:
2348                i -= 2;
2349                if (i >= nents) {
2350                        ret = 1;
2351                        goto out;
2352                }
2353                p = ents + i;
2354                last = &ents[nents - 1];
2355                while (p <= last) {
2356                        if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2357                                goto out;
2358                        filp->f_pos++;
2359                        p++;
2360                }
2361        }
2362
2363        ret = 1;
2364out:
2365        put_task_struct(task);
2366out_no_task:
2367        return ret;
2368}
2369
2370#ifdef CONFIG_SECURITY
2371static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2372                                  size_t count, loff_t *ppos)
2373{
2374        struct inode * inode = file->f_path.dentry->d_inode;
2375        char *p = NULL;
2376        ssize_t length;
2377        struct task_struct *task = get_proc_task(inode);
2378
2379        if (!task)
2380                return -ESRCH;
2381
2382        length = security_getprocattr(task,
2383                                      (char*)file->f_path.dentry->d_name.name,
2384                                      &p);
2385        put_task_struct(task);
2386        if (length > 0)
2387                length = simple_read_from_buffer(buf, count, ppos, p, length);
2388        kfree(p);
2389        return length;
2390}
2391
2392static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2393                                   size_t count, loff_t *ppos)
2394{
2395        struct inode * inode = file->f_path.dentry->d_inode;
2396        char *page;
2397        ssize_t length;
2398        struct task_struct *task = get_proc_task(inode);
2399
2400        length = -ESRCH;
2401        if (!task)
2402                goto out_no_task;
2403        if (count > PAGE_SIZE)
2404                count = PAGE_SIZE;
2405
2406        /* No partial writes. */
2407        length = -EINVAL;
2408        if (*ppos != 0)
2409                goto out;
2410
2411        length = -ENOMEM;
2412        page = (char*)__get_free_page(GFP_TEMPORARY);
2413        if (!page)
2414                goto out;
2415
2416        length = -EFAULT;
2417        if (copy_from_user(page, buf, count))
2418                goto out_free;
2419
2420        /* Guard against adverse ptrace interaction */
2421        length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2422        if (length < 0)
2423                goto out_free;
2424
2425        length = security_setprocattr(task,
2426                                      (char*)file->f_path.dentry->d_name.name,
2427                                      (void*)page, count);
2428        mutex_unlock(&task->signal->cred_guard_mutex);
2429out_free:
2430        free_page((unsigned long) page);
2431out:
2432        put_task_struct(task);
2433out_no_task:
2434        return length;
2435}
2436
2437static const struct file_operations proc_pid_attr_operations = {
2438        .read           = proc_pid_attr_read,
2439        .write          = proc_pid_attr_write,
2440        .llseek         = generic_file_llseek,
2441};
2442
2443static const struct pid_entry attr_dir_stuff[] = {
2444        REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2445        REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2446        REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2447        REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2448        REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2449        REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2450};
2451
2452static int proc_attr_dir_readdir(struct file * filp,
2453                             void * dirent, filldir_t filldir)
2454{
2455        return proc_pident_readdir(filp,dirent,filldir,
2456                                   attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2457}
2458
2459static const struct file_operations proc_attr_dir_operations = {
2460        .read           = generic_read_dir,
2461        .readdir        = proc_attr_dir_readdir,
2462        .llseek         = default_llseek,
2463};
2464
2465static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2466                                struct dentry *dentry, struct nameidata *nd)
2467{
2468        return proc_pident_lookup(dir, dentry,
2469                                  attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2470}
2471
2472static const struct inode_operations proc_attr_dir_inode_operations = {
2473        .lookup         = proc_attr_dir_lookup,
2474        .getattr        = pid_getattr,
2475        .setattr        = proc_setattr,
2476};
2477
2478#endif
2479
2480#ifdef CONFIG_ELF_CORE
2481static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2482                                         size_t count, loff_t *ppos)
2483{
2484        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2485        struct mm_struct *mm;
2486        char buffer[PROC_NUMBUF];
2487        size_t len;
2488        int ret;
2489
2490        if (!task)
2491                return -ESRCH;
2492
2493        ret = 0;
2494        mm = get_task_mm(task);
2495        if (mm) {
2496                len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2497                               ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2498                                MMF_DUMP_FILTER_SHIFT));
2499                mmput(mm);
2500                ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2501        }
2502
2503        put_task_struct(task);
2504
2505        return ret;
2506}
2507
2508static ssize_t proc_coredump_filter_write(struct file *file,
2509                                          const char __user *buf,
2510                                          size_t count,
2511                                          loff_t *ppos)
2512{
2513        struct task_struct *task;
2514        struct mm_struct *mm;
2515        char buffer[PROC_NUMBUF], *end;
2516        unsigned int val;
2517        int ret;
2518        int i;
2519        unsigned long mask;
2520
2521        ret = -EFAULT;
2522        memset(buffer, 0, sizeof(buffer));
2523        if (count > sizeof(buffer) - 1)
2524                count = sizeof(buffer) - 1;
2525        if (copy_from_user(buffer, buf, count))
2526                goto out_no_task;
2527
2528        ret = -EINVAL;
2529        val = (unsigned int)simple_strtoul(buffer, &end, 0);
2530        if (*end == '\n')
2531                end++;
2532        if (end - buffer == 0)
2533                goto out_no_task;
2534
2535        ret = -ESRCH;
2536        task = get_proc_task(file->f_dentry->d_inode);
2537        if (!task)
2538                goto out_no_task;
2539
2540        ret = end - buffer;
2541        mm = get_task_mm(task);
2542        if (!mm)
2543                goto out_no_mm;
2544
2545        for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2546                if (val & mask)
2547                        set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2548                else
2549                        clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2550        }
2551
2552        mmput(mm);
2553 out_no_mm:
2554        put_task_struct(task);
2555 out_no_task:
2556        return ret;
2557}
2558
2559static const struct file_operations proc_coredump_filter_operations = {
2560        .read           = proc_coredump_filter_read,
2561        .write          = proc_coredump_filter_write,
2562        .llseek         = generic_file_llseek,
2563};
2564#endif
2565
2566/*
2567 * /proc/self:
2568 */
2569static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2570                              int buflen)
2571{
2572        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2573        pid_t tgid = task_tgid_nr_ns(current, ns);
2574        char tmp[PROC_NUMBUF];
2575        if (!tgid)
2576                return -ENOENT;
2577        sprintf(tmp, "%d", tgid);
2578        return vfs_readlink(dentry,buffer,buflen,tmp);
2579}
2580
2581static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2582{
2583        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2584        pid_t tgid = task_tgid_nr_ns(current, ns);
2585        char *name = ERR_PTR(-ENOENT);
2586        if (tgid) {
2587                name = __getname();
2588                if (!name)
2589                        name = ERR_PTR(-ENOMEM);
2590                else
2591                        sprintf(name, "%d", tgid);
2592        }
2593        nd_set_link(nd, name);
2594        return NULL;
2595}
2596
2597static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
2598                                void *cookie)
2599{
2600        char *s = nd_get_link(nd);
2601        if (!IS_ERR(s))
2602                __putname(s);
2603}
2604
2605static const struct inode_operations proc_self_inode_operations = {
2606        .readlink       = proc_self_readlink,
2607        .follow_link    = proc_self_follow_link,
2608        .put_link       = proc_self_put_link,
2609};
2610
2611/*
2612 * proc base
2613 *
2614 * These are the directory entries in the root directory of /proc
2615 * that properly belong to the /proc filesystem, as they describe
2616 * describe something that is process related.
2617 */
2618static const struct pid_entry proc_base_stuff[] = {
2619        NOD("self", S_IFLNK|S_IRWXUGO,
2620                &proc_self_inode_operations, NULL, {}),
2621};
2622
2623static struct dentry *proc_base_instantiate(struct inode *dir,
2624        struct dentry *dentry, struct task_struct *task, const void *ptr)
2625{
2626        const struct pid_entry *p = ptr;
2627        struct inode *inode;
2628        struct proc_inode *ei;
2629        struct dentry *error;
2630
2631        /* Allocate the inode */
2632        error = ERR_PTR(-ENOMEM);
2633        inode = new_inode(dir->i_sb);
2634        if (!inode)
2635                goto out;
2636
2637        /* Initialize the inode */
2638        ei = PROC_I(inode);
2639        inode->i_ino = get_next_ino();
2640        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2641
2642        /*
2643         * grab the reference to the task.
2644         */
2645        ei->pid = get_task_pid(task, PIDTYPE_PID);
2646        if (!ei->pid)
2647                goto out_iput;
2648
2649        inode->i_mode = p->mode;
2650        if (S_ISDIR(inode->i_mode))
2651                inode->i_nlink = 2;
2652        if (S_ISLNK(inode->i_mode))
2653                inode->i_size = 64;
2654        if (p->iop)
2655                inode->i_op = p->iop;
2656        if (p->fop)
2657                inode->i_fop = p->fop;
2658        ei->op = p->op;
2659        d_add(dentry, inode);
2660        error = NULL;
2661out:
2662        return error;
2663out_iput:
2664        iput(inode);
2665        goto out;
2666}
2667
2668static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2669{
2670        struct dentry *error;
2671        struct task_struct *task = get_proc_task(dir);
2672        const struct pid_entry *p, *last;
2673
2674        error = ERR_PTR(-ENOENT);
2675
2676        if (!task)
2677                goto out_no_task;
2678
2679        /* Lookup the directory entry */
2680        last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2681        for (p = proc_base_stuff; p <= last; p++) {
2682                if (p->len != dentry->d_name.len)
2683                        continue;
2684                if (!memcmp(dentry->d_name.name, p->name, p->len))
2685                        break;
2686        }
2687        if (p > last)
2688                goto out;
2689
2690        error = proc_base_instantiate(dir, dentry, task, p);
2691
2692out:
2693        put_task_struct(task);
2694out_no_task:
2695        return error;
2696}
2697
2698static int proc_base_fill_cache(struct file *filp, void *dirent,
2699        filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2700{
2701        return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2702                                proc_base_instantiate, task, p);
2703}
2704
2705#ifdef CONFIG_TASK_IO_ACCOUNTING
2706static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2707{
2708        struct task_io_accounting acct = task->ioac;
2709        unsigned long flags;
2710        int result;
2711
2712        result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2713        if (result)
2714                return result;
2715
2716        if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
2717                result = -EACCES;
2718                goto out_unlock;
2719        }
2720
2721        if (whole && lock_task_sighand(task, &flags)) {
2722                struct task_struct *t = task;
2723
2724                task_io_accounting_add(&acct, &task->signal->ioac);
2725                while_each_thread(task, t)
2726                        task_io_accounting_add(&acct, &t->ioac);
2727
2728                unlock_task_sighand(task, &flags);
2729        }
2730        result = sprintf(buffer,
2731                        "rchar: %llu\n"
2732                        "wchar: %llu\n"
2733                        "syscr: %llu\n"
2734                        "syscw: %llu\n"
2735                        "read_bytes: %llu\n"
2736                        "write_bytes: %llu\n"
2737                        "cancelled_write_bytes: %llu\n",
2738                        (unsigned long long)acct.rchar,
2739                        (unsigned long long)acct.wchar,
2740                        (unsigned long long)acct.syscr,
2741                        (unsigned long long)acct.syscw,
2742                        (unsigned long long)acct.read_bytes,
2743                        (unsigned long long)acct.write_bytes,
2744                        (unsigned long long)acct.cancelled_write_bytes);
2745out_unlock:
2746        mutex_unlock(&task->signal->cred_guard_mutex);
2747        return result;
2748}
2749
2750static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2751{
2752        return do_io_accounting(task, buffer, 0);
2753}
2754
2755static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2756{
2757        return do_io_accounting(task, buffer, 1);
2758}
2759#endif /* CONFIG_TASK_IO_ACCOUNTING */
2760
2761static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2762                                struct pid *pid, struct task_struct *task)
2763{
2764        int err = lock_trace(task);
2765        if (!err) {
2766                seq_printf(m, "%08x\n", task->personality);
2767                unlock_trace(task);
2768        }
2769        return err;
2770}
2771
2772/*
2773 * Thread groups
2774 */
2775static const struct file_operations proc_task_operations;
2776static const struct inode_operations proc_task_inode_operations;
2777
2778static const struct pid_entry tgid_base_stuff[] = {
2779        DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2780        DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2781        DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2782        DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2783#ifdef CONFIG_NET
2784        DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2785#endif
2786        REG("environ",    S_IRUSR, proc_environ_operations),
2787        INF("auxv",       S_IRUSR, proc_pid_auxv),
2788        ONE("status",     S_IRUGO, proc_pid_status),
2789        ONE("personality", S_IRUGO, proc_pid_personality),
2790        INF("limits",     S_IRUGO, proc_pid_limits),
2791#ifdef CONFIG_SCHED_DEBUG
2792        REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2793#endif
2794#ifdef CONFIG_SCHED_AUTOGROUP
2795        REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2796#endif
2797        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2798#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2799        INF("syscall",    S_IRUGO, proc_pid_syscall),
2800#endif
2801        INF("cmdline",    S_IRUGO, proc_pid_cmdline),
2802        ONE("stat",       S_IRUGO, proc_tgid_stat),
2803        ONE("statm",      S_IRUGO, proc_pid_statm),
2804        REG("maps",       S_IRUGO, proc_maps_operations),
2805#ifdef CONFIG_NUMA
2806        REG("numa_maps",  S_IRUGO, proc_numa_maps_operations),
2807#endif
2808        REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2809        LNK("cwd",        proc_cwd_link),
2810        LNK("root",       proc_root_link),
2811        LNK("exe",        proc_exe_link),
2812        REG("mounts",     S_IRUGO, proc_mounts_operations),
2813        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2814        REG("mountstats", S_IRUSR, proc_mountstats_operations),
2815#ifdef CONFIG_PROC_PAGE_MONITOR
2816        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2817        REG("smaps",      S_IRUGO, proc_smaps_operations),
2818        REG("pagemap",    S_IRUGO, proc_pagemap_operations),
2819#endif
2820#ifdef CONFIG_SECURITY
2821        DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2822#endif
2823#ifdef CONFIG_KALLSYMS
2824        INF("wchan",      S_IRUGO, proc_pid_wchan),
2825#endif
2826#ifdef CONFIG_STACKTRACE
2827        ONE("stack",      S_IRUGO, proc_pid_stack),
2828#endif
2829#ifdef CONFIG_SCHEDSTATS
2830        INF("schedstat",  S_IRUGO, proc_pid_schedstat),
2831#endif
2832#ifdef CONFIG_LATENCYTOP
2833        REG("latency",  S_IRUGO, proc_lstats_operations),
2834#endif
2835#ifdef CONFIG_PROC_PID_CPUSET
2836        REG("cpuset",     S_IRUGO, proc_cpuset_operations),
2837#endif
2838#ifdef CONFIG_CGROUPS
2839        REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2840#endif
2841        INF("oom_score",  S_IRUGO, proc_oom_score),
2842        REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
2843        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2844#ifdef CONFIG_AUDITSYSCALL
2845        REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2846        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2847#endif
2848#ifdef CONFIG_FAULT_INJECTION
2849        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2850#endif
2851#ifdef CONFIG_ELF_CORE
2852        REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2853#endif
2854#ifdef CONFIG_TASK_IO_ACCOUNTING
2855        INF("io",       S_IRUSR, proc_tgid_io_accounting),
2856#endif
2857#ifdef CONFIG_HARDWALL
2858        INF("hardwall",   S_IRUGO, proc_pid_hardwall),
2859#endif
2860};
2861
2862static int proc_tgid_base_readdir(struct file * filp,
2863                             void * dirent, filldir_t filldir)
2864{
2865        return proc_pident_readdir(filp,dirent,filldir,
2866                                   tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2867}
2868
2869static const struct file_operations proc_tgid_base_operations = {
2870        .read           = generic_read_dir,
2871        .readdir        = proc_tgid_base_readdir,
2872        .llseek         = default_llseek,
2873};
2874
2875static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2876        return proc_pident_lookup(dir, dentry,
2877                                  tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2878}
2879
2880static const struct inode_operations proc_tgid_base_inode_operations = {
2881        .lookup         = proc_tgid_base_lookup,
2882        .getattr        = pid_getattr,
2883        .setattr        = proc_setattr,
2884};
2885
2886static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2887{
2888        struct dentry *dentry, *leader, *dir;
2889        char buf[PROC_NUMBUF];
2890        struct qstr name;
2891
2892        name.name = buf;
2893        name.len = snprintf(buf, sizeof(buf), "%d", pid);
2894        dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2895        if (dentry) {
2896                shrink_dcache_parent(dentry);
2897                d_drop(dentry);
2898                dput(dentry);
2899        }
2900
2901        name.name = buf;
2902        name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2903        leader = d_hash_and_lookup(mnt->mnt_root, &name);
2904        if (!leader)
2905                goto out;
2906
2907        name.name = "task";
2908        name.len = strlen(name.name);
2909        dir = d_hash_and_lookup(leader, &name);
2910        if (!dir)
2911                goto out_put_leader;
2912
2913        name.name = buf;
2914        name.len = snprintf(buf, sizeof(buf), "%d", pid);
2915        dentry = d_hash_and_lookup(dir, &name);
2916        if (dentry) {
2917                shrink_dcache_parent(dentry);
2918                d_drop(dentry);
2919                dput(dentry);
2920        }
2921
2922        dput(dir);
2923out_put_leader:
2924        dput(leader);
2925out:
2926        return;
2927}
2928
2929/**
2930 * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2931 * @task: task that should be flushed.
2932 *
2933 * When flushing dentries from proc, one needs to flush them from global
2934 * proc (proc_mnt) and from all the namespaces' procs this task was seen
2935 * in. This call is supposed to do all of this job.
2936 *
2937 * Looks in the dcache for
2938 * /proc/@pid
2939 * /proc/@tgid/task/@pid
2940 * if either directory is present flushes it and all of it'ts children
2941 * from the dcache.
2942 *
2943 * It is safe and reasonable to cache /proc entries for a task until
2944 * that task exits.  After that they just clog up the dcache with
2945 * useless entries, possibly causing useful dcache entries to be
2946 * flushed instead.  This routine is proved to flush those useless
2947 * dcache entries at process exit time.
2948 *
2949 * NOTE: This routine is just an optimization so it does not guarantee
2950 *       that no dcache entries will exist at process exit time it
2951 *       just makes it very unlikely that any will persist.
2952 */
2953
2954void proc_flush_task(struct task_struct *task)
2955{
2956        int i;
2957        struct pid *pid, *tgid;
2958        struct upid *upid;
2959
2960        pid = task_pid(task);
2961        tgid = task_tgid(task);
2962
2963        for (i = 0; i <= pid->level; i++) {
2964                upid = &pid->numbers[i];
2965                proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2966                                        tgid->numbers[i].nr);
2967        }
2968
2969        upid = &pid->numbers[pid->level];
2970        if (upid->nr == 1)
2971                pid_ns_release_proc(upid->ns);
2972}
2973
2974static struct dentry *proc_pid_instantiate(struct inode *dir,
2975                                           struct dentry * dentry,
2976                                           struct task_struct *task, const void *ptr)
2977{
2978        struct dentry *error = ERR_PTR(-ENOENT);
2979        struct inode *inode;
2980
2981        inode = proc_pid_make_inode(dir->i_sb, task);
2982        if (!inode)
2983                goto out;
2984
2985        inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2986        inode->i_op = &proc_tgid_base_inode_operations;
2987        inode->i_fop = &proc_tgid_base_operations;
2988        inode->i_flags|=S_IMMUTABLE;
2989
2990        inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
2991                ARRAY_SIZE(tgid_base_stuff));
2992
2993        d_set_d_op(dentry, &pid_dentry_operations);
2994
2995        d_add(dentry, inode);
2996        /* Close the race of the process dying before we return the dentry */
2997        if (pid_revalidate(dentry, NULL))
2998                error = NULL;
2999out:
3000        return error;
3001}
3002
3003struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3004{
3005        struct dentry *result;
3006        struct task_struct *task;
3007        unsigned tgid;
3008        struct pid_namespace *ns;
3009
3010        result = proc_base_lookup(dir, dentry);
3011        if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
3012                goto out;
3013
3014        tgid = name_to_int(dentry);
3015        if (tgid == ~0U)
3016                goto out;
3017
3018        ns = dentry->d_sb->s_fs_info;
3019        rcu_read_lock();
3020        task = find_task_by_pid_ns(tgid, ns);
3021        if (task)
3022                get_task_struct(task);
3023        rcu_read_unlock();
3024        if (!task)
3025                goto out;
3026
3027        result = proc_pid_instantiate(dir, dentry, task, NULL);
3028        put_task_struct(task);
3029out:
3030        return result;
3031}
3032
3033/*
3034 * Find the first task with tgid >= tgid
3035 *
3036 */
3037struct tgid_iter {
3038        unsigned int tgid;
3039        struct task_struct *task;
3040};
3041static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3042{
3043        struct pid *pid;
3044
3045        if (iter.task)
3046                put_task_struct(iter.task);
3047        rcu_read_lock();
3048retry:
3049        iter.task = NULL;
3050        pid = find_ge_pid(iter.tgid, ns);
3051        if (pid) {
3052                iter.tgid = pid_nr_ns(pid, ns);
3053                iter.task = pid_task(pid, PIDTYPE_PID);
3054                /* What we to know is if the pid we have find is the
3055                 * pid of a thread_group_leader.  Testing for task
3056                 * being a thread_group_leader is the obvious thing
3057                 * todo but there is a window when it fails, due to
3058                 * the pid transfer logic in de_thread.
3059                 *
3060                 * So we perform the straight forward test of seeing
3061                 * if the pid we have found is the pid of a thread
3062                 * group leader, and don't worry if the task we have
3063                 * found doesn't happen to be a thread group leader.
3064                 * As we don't care in the case of readdir.
3065                 */
3066                if (!iter.task || !has_group_leader_pid(iter.task)) {
3067                        iter.tgid += 1;
3068                        goto retry;
3069                }
3070                get_task_struct(iter.task);
3071        }
3072        rcu_read_unlock();
3073        return iter;
3074}
3075
3076#define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
3077
3078static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3079        struct tgid_iter iter)
3080{
3081        char name[PROC_NUMBUF];
3082        int len = snprintf(name, sizeof(name), "%d", iter.tgid);
3083        return proc_fill_cache(filp, dirent, filldir, name, len,
3084                                proc_pid_instantiate, iter.task, NULL);
3085}
3086
3087/* for the /proc/ directory itself, after non-process stuff has been done */
3088int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
3089{
3090        unsigned int nr;
3091        struct task_struct *reaper;
3092        struct tgid_iter iter;
3093        struct pid_namespace *ns;
3094
3095        if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
3096                goto out_no_task;
3097        nr = filp->f_pos - FIRST_PROCESS_ENTRY;
3098
3099        reaper = get_proc_task(filp->f_path.dentry->d_inode);
3100        if (!reaper)
3101                goto out_no_task;
3102
3103        for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
3104                const struct pid_entry *p = &proc_base_stuff[nr];
3105                if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
3106                        goto out;
3107        }
3108
3109        ns = filp->f_dentry->d_sb->s_fs_info;
3110        iter.task = NULL;
3111        iter.tgid = filp->f_pos - TGID_OFFSET;
3112        for (iter = next_tgid(ns, iter);
3113             iter.task;
3114             iter.tgid += 1, iter = next_tgid(ns, iter)) {
3115                filp->f_pos = iter.tgid + TGID_OFFSET;
3116                if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
3117                        put_task_struct(iter.task);
3118                        goto out;
3119                }
3120        }
3121        filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
3122out:
3123        put_task_struct(reaper);
3124out_no_task:
3125        return 0;
3126}
3127
3128/*
3129 * Tasks
3130 */
3131static const struct pid_entry tid_base_stuff[] = {
3132        DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3133        DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3134        DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3135        REG("environ",   S_IRUSR, proc_environ_operations),
3136        INF("auxv",      S_IRUSR, proc_pid_auxv),
3137        ONE("status",    S_IRUGO, proc_pid_status),
3138        ONE("personality", S_IRUGO, proc_pid_personality),
3139        INF("limits",    S_IRUGO, proc_pid_limits),
3140#ifdef CONFIG_SCHED_DEBUG
3141        REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3142#endif
3143        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3144#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3145        INF("syscall",   S_IRUGO, proc_pid_syscall),
3146#endif
3147        INF("cmdline",   S_IRUGO, proc_pid_cmdline),
3148        ONE("stat",      S_IRUGO, proc_tid_stat),
3149        ONE("statm",     S_IRUGO, proc_pid_statm),
3150        REG("maps",      S_IRUGO, proc_maps_operations),
3151#ifdef CONFIG_NUMA
3152        REG("numa_maps", S_IRUGO, proc_numa_maps_operations),
3153#endif
3154        REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3155        LNK("cwd",       proc_cwd_link),
3156        LNK("root",      proc_root_link),
3157        LNK("exe",       proc_exe_link),
3158        REG("mounts",    S_IRUGO, proc_mounts_operations),
3159        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3160#ifdef CONFIG_PROC_PAGE_MONITOR
3161        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3162        REG("smaps",     S_IRUGO, proc_smaps_operations),
3163        REG("pagemap",    S_IRUGO, proc_pagemap_operations),
3164#endif
3165#ifdef CONFIG_SECURITY
3166        DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3167#endif
3168#ifdef CONFIG_KALLSYMS
3169        INF("wchan",     S_IRUGO, proc_pid_wchan),
3170#endif
3171#ifdef CONFIG_STACKTRACE
3172        ONE("stack",      S_IRUGO, proc_pid_stack),
3173#endif
3174#ifdef CONFIG_SCHEDSTATS
3175        INF("schedstat", S_IRUGO, proc_pid_schedstat),
3176#endif
3177#ifdef CONFIG_LATENCYTOP
3178        REG("latency",  S_IRUGO, proc_lstats_operations),
3179#endif
3180#ifdef CONFIG_PROC_PID_CPUSET
3181        REG("cpuset",    S_IRUGO, proc_cpuset_operations),
3182#endif
3183#ifdef CONFIG_CGROUPS
3184        REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3185#endif
3186        INF("oom_score", S_IRUGO, proc_oom_score),
3187        REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
3188        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3189#ifdef CONFIG_AUDITSYSCALL
3190        REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3191        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3192#endif
3193#ifdef CONFIG_FAULT_INJECTION
3194        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3195#endif
3196#ifdef CONFIG_TASK_IO_ACCOUNTING
3197        INF("io",       S_IRUSR, proc_tid_io_accounting),
3198#endif
3199#ifdef CONFIG_HARDWALL
3200        INF("hardwall",   S_IRUGO, proc_pid_hardwall),
3201#endif
3202};
3203
3204static int proc_tid_base_readdir(struct file * filp,
3205                             void * dirent, filldir_t filldir)
3206{
3207        return proc_pident_readdir(filp,dirent,filldir,
3208                                   tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
3209}
3210
3211static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
3212        return proc_pident_lookup(dir, dentry,
3213                                  tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3214}
3215
3216static const struct file_operations proc_tid_base_operations = {
3217        .read           = generic_read_dir,
3218        .readdir        = proc_tid_base_readdir,
3219        .llseek         = default_llseek,
3220};
3221
3222static const struct inode_operations proc_tid_base_inode_operations = {
3223        .lookup         = proc_tid_base_lookup,
3224        .getattr        = pid_getattr,
3225        .setattr        = proc_setattr,
3226};
3227
3228static struct dentry *proc_task_instantiate(struct inode *dir,
3229        struct dentry *dentry, struct task_struct *task, const void *ptr)
3230{
3231        struct dentry *error = ERR_PTR(-ENOENT);
3232        struct inode *inode;
3233        inode = proc_pid_make_inode(dir->i_sb, task);
3234
3235        if (!inode)
3236                goto out;
3237        inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3238        inode->i_op = &proc_tid_base_inode_operations;
3239        inode->i_fop = &proc_tid_base_operations;
3240        inode->i_flags|=S_IMMUTABLE;
3241
3242        inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
3243                ARRAY_SIZE(tid_base_stuff));
3244
3245        d_set_d_op(dentry, &pid_dentry_operations);
3246
3247        d_add(dentry, inode);
3248        /* Close the race of the process dying before we return the dentry */
3249        if (pid_revalidate(dentry, NULL))
3250                error = NULL;
3251out:
3252        return error;
3253}
3254
3255static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3256{
3257        struct dentry *result = ERR_PTR(-ENOENT);
3258        struct task_struct *task;
3259        struct task_struct *leader = get_proc_task(dir);
3260        unsigned tid;
3261        struct pid_namespace *ns;
3262
3263        if (!leader)
3264                goto out_no_task;
3265
3266        tid = name_to_int(dentry);
3267        if (tid == ~0U)
3268                goto out;
3269
3270        ns = dentry->d_sb->s_fs_info;
3271        rcu_read_lock();
3272        task = find_task_by_pid_ns(tid, ns);
3273        if (task)
3274                get_task_struct(task);
3275        rcu_read_unlock();
3276        if (!task)
3277                goto out;
3278        if (!same_thread_group(leader, task))
3279                goto out_drop_task;
3280
3281        result = proc_task_instantiate(dir, dentry, task, NULL);
3282out_drop_task:
3283        put_task_struct(task);
3284out:
3285        put_task_struct(leader);
3286out_no_task:
3287        return result;
3288}
3289
3290/*
3291 * Find the first tid of a thread group to return to user space.
3292 *
3293 * Usually this is just the thread group leader, but if the users
3294 * buffer was too small or there was a seek into the middle of the
3295 * directory we have more work todo.
3296 *
3297 * In the case of a short read we start with find_task_by_pid.
3298 *
3299 * In the case of a seek we start with the leader and walk nr
3300 * threads past it.
3301 */
3302static struct task_struct *first_tid(struct task_struct *leader,
3303                int tid, int nr, struct pid_namespace *ns)
3304{
3305        struct task_struct *pos;
3306
3307        rcu_read_lock();
3308        /* Attempt to start with the pid of a thread */
3309        if (tid && (nr > 0)) {
3310                pos = find_task_by_pid_ns(tid, ns);
3311                if (pos && (pos->group_leader == leader))
3312                        goto found;
3313        }
3314
3315        /* If nr exceeds the number of threads there is nothing todo */
3316        pos = NULL;
3317        if (nr && nr >= get_nr_threads(leader))
3318                goto out;
3319
3320        /* If we haven't found our starting place yet start
3321         * with the leader and walk nr threads forward.
3322         */
3323        for (pos = leader; nr > 0; --nr) {
3324                pos = next_thread(pos);
3325                if (pos == leader) {
3326                        pos = NULL;
3327                        goto out;
3328                }
3329        }
3330found:
3331        get_task_struct(pos);
3332out:
3333        rcu_read_unlock();
3334        return pos;
3335}
3336
3337/*
3338 * Find the next thread in the thread list.
3339 * Return NULL if there is an error or no next thread.
3340 *
3341 * The reference to the input task_struct is released.
3342 */
3343static struct task_struct *next_tid(struct task_struct *start)
3344{
3345        struct task_struct *pos = NULL;
3346        rcu_read_lock();
3347        if (pid_alive(start)) {
3348                pos = next_thread(start);
3349                if (thread_group_leader(pos))
3350                        pos = NULL;
3351                else
3352                        get_task_struct(pos);
3353        }
3354        rcu_read_unlock();
3355        put_task_struct(start);
3356        return pos;
3357}
3358
3359static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3360        struct task_struct *task, int tid)
3361{
3362        char name[PROC_NUMBUF];
3363        int len = snprintf(name, sizeof(name), "%d", tid);
3364        return proc_fill_cache(filp, dirent, filldir, name, len,
3365                                proc_task_instantiate, task, NULL);
3366}
3367
3368/* for the /proc/TGID/task/ directories */
3369static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3370{
3371        struct dentry *dentry = filp->f_path.dentry;
3372        struct inode *inode = dentry->d_inode;
3373        struct task_struct *leader = NULL;
3374        struct task_struct *task;
3375        int retval = -ENOENT;
3376        ino_t ino;
3377        int tid;
3378        struct pid_namespace *ns;
3379
3380        task = get_proc_task(inode);
3381        if (!task)
3382                goto out_no_task;
3383        rcu_read_lock();
3384        if (pid_alive(task)) {
3385                leader = task->group_leader;
3386                get_task_struct(leader);
3387        }
3388        rcu_read_unlock();
3389        put_task_struct(task);
3390        if (!leader)
3391                goto out_no_task;
3392        retval = 0;
3393
3394        switch ((unsigned long)filp->f_pos) {
3395        case 0:
3396                ino = inode->i_ino;
3397                if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) < 0)
3398                        goto out;
3399                filp->f_pos++;
3400                /* fall through */
3401        case 1:
3402                ino = parent_ino(dentry);
3403                if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) < 0)
3404                        goto out;
3405                filp->f_pos++;
3406                /* fall through */
3407        }
3408
3409        /* f_version caches the tgid value that the last readdir call couldn't
3410         * return. lseek aka telldir automagically resets f_version to 0.
3411         */
3412        ns = filp->f_dentry->d_sb->s_fs_info;
3413        tid = (int)filp->f_version;
3414        filp->f_version = 0;
3415        for (task = first_tid(leader, tid, filp->f_pos - 2, ns);
3416             task;
3417             task = next_tid(task), filp->f_pos++) {
3418                tid = task_pid_nr_ns(task, ns);
3419                if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3420                        /* returning this tgid failed, save it as the first
3421                         * pid for the next readir call */
3422                        filp->f_version = (u64)tid;
3423                        put_task_struct(task);
3424                        break;
3425                }
3426        }
3427out:
3428        put_task_struct(leader);
3429out_no_task:
3430        return retval;
3431}
3432
3433static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3434{
3435        struct inode *inode = dentry->d_inode;
3436        struct task_struct *p = get_proc_task(inode);
3437        generic_fillattr(inode, stat);
3438
3439        if (p) {
3440                stat->nlink += get_nr_threads(p);
3441                put_task_struct(p);
3442        }
3443
3444        return 0;
3445}
3446
3447static const struct inode_operations proc_task_inode_operations = {
3448        .lookup         = proc_task_lookup,
3449        .getattr        = proc_task_getattr,
3450        .setattr        = proc_setattr,
3451};
3452
3453static const struct file_operations proc_task_operations = {
3454        .read           = generic_read_dir,
3455        .readdir        = proc_task_readdir,
3456        .llseek         = default_llseek,
3457};
3458
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