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