linux/fs/proc/base.c
<<
>>
Prefs
   1/*
   2 *  linux/fs/proc/base.c
   3 *
   4 *  Copyright (C) 1991, 1992 Linus Torvalds
   5 *
   6 *  proc base directory handling functions
   7 *
   8 *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
   9 *  Instead of using magical inumbers to determine the kind of object
  10 *  we allocate and fill in-core inodes upon lookup. They don't even
  11 *  go into icache. We cache the reference to task_struct upon lookup too.
  12 *  Eventually it should become a filesystem in its own. We don't use the
  13 *  rest of procfs anymore.
  14 *
  15 *
  16 *  Changelog:
  17 *  17-Jan-2005
  18 *  Allan Bezerra
  19 *  Bruna Moreira <bruna.moreira@indt.org.br>
  20 *  Edjard Mota <edjard.mota@indt.org.br>
  21 *  Ilias Biris <ilias.biris@indt.org.br>
  22 *  Mauricio Lin <mauricio.lin@indt.org.br>
  23 *
  24 *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  25 *
  26 *  A new process specific entry (smaps) included in /proc. It shows the
  27 *  size of rss for each memory area. The maps entry lacks information
  28 *  about physical memory size (rss) for each mapped file, i.e.,
  29 *  rss information for executables and library files.
  30 *  This additional information is useful for any tools that need to know
  31 *  about physical memory consumption for a process specific library.
  32 *
  33 *  Changelog:
  34 *  21-Feb-2005
  35 *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  36 *  Pud inclusion in the page table walking.
  37 *
  38 *  ChangeLog:
  39 *  10-Mar-2005
  40 *  10LE Instituto Nokia de Tecnologia - INdT:
  41 *  A better way to walks through the page table as suggested by Hugh Dickins.
  42 *
  43 *  Simo Piiroinen <simo.piiroinen@nokia.com>:
  44 *  Smaps information related to shared, private, clean and dirty pages.
  45 *
  46 *  Paul Mundt <paul.mundt@nokia.com>:
  47 *  Overall revision about smaps.
  48 */
  49
  50#include <asm/uaccess.h>
  51
  52#include <linux/errno.h>
  53#include <linux/time.h>
  54#include <linux/proc_fs.h>
  55#include <linux/stat.h>
  56#include <linux/task_io_accounting_ops.h>
  57#include <linux/init.h>
  58#include <linux/capability.h>
  59#include <linux/file.h>
  60#include <linux/fdtable.h>
  61#include <linux/string.h>
  62#include <linux/seq_file.h>
  63#include <linux/namei.h>
  64#include <linux/mnt_namespace.h>
  65#include <linux/mm.h>
  66#include <linux/swap.h>
  67#include <linux/rcupdate.h>
  68#include <linux/kallsyms.h>
  69#include <linux/stacktrace.h>
  70#include <linux/resource.h>
  71#include <linux/module.h>
  72#include <linux/mount.h>
  73#include <linux/security.h>
  74#include <linux/ptrace.h>
  75#include <linux/tracehook.h>
  76#include <linux/cgroup.h>
  77#include <linux/cpuset.h>
  78#include <linux/audit.h>
  79#include <linux/poll.h>
  80#include <linux/nsproxy.h>
  81#include <linux/oom.h>
  82#include <linux/elf.h>
  83#include <linux/pid_namespace.h>
  84#include <linux/fs_struct.h>
  85#include <linux/slab.h>
  86#ifdef CONFIG_HARDWALL
  87#include <asm/hardwall.h>
  88#endif
  89#include "internal.h"
  90
  91/* NOTE:
  92 *      Implementing inode permission operations in /proc is almost
  93 *      certainly an error.  Permission checks need to happen during
  94 *      each system call not at open time.  The reason is that most of
  95 *      what we wish to check for permissions in /proc varies at runtime.
  96 *
  97 *      The classic example of a problem is opening file descriptors
  98 *      in /proc for a task before it execs a suid executable.
  99 */
 100
 101struct pid_entry {
 102        char *name;
 103        int len;
 104        mode_t mode;
 105        const struct inode_operations *iop;
 106        const struct file_operations *fop;
 107        union proc_op op;
 108};
 109
 110#define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 111        .name = (NAME),                                 \
 112        .len  = sizeof(NAME) - 1,                       \
 113        .mode = MODE,                                   \
 114        .iop  = IOP,                                    \
 115        .fop  = FOP,                                    \
 116        .op   = OP,                                     \
 117}
 118
 119#define DIR(NAME, MODE, iops, fops)     \
 120        NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 121#define LNK(NAME, get_link)                                     \
 122        NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 123                &proc_pid_link_inode_operations, NULL,          \
 124                { .proc_get_link = get_link } )
 125#define REG(NAME, MODE, fops)                           \
 126        NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 127#define INF(NAME, MODE, read)                           \
 128        NOD(NAME, (S_IFREG|(MODE)),                     \
 129                NULL, &proc_info_file_operations,       \
 130                { .proc_read = read } )
 131#define ONE(NAME, MODE, show)                           \
 132        NOD(NAME, (S_IFREG|(MODE)),                     \
 133                NULL, &proc_single_file_operations,     \
 134                { .proc_show = show } )
 135
 136/*
 137 * Count the number of hardlinks for the pid_entry table, excluding the .
 138 * and .. links.
 139 */
 140static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
 141        unsigned int n)
 142{
 143        unsigned int i;
 144        unsigned int count;
 145
 146        count = 0;
 147        for (i = 0; i < n; ++i) {
 148                if (S_ISDIR(entries[i].mode))
 149                        ++count;
 150        }
 151
 152        return count;
 153}
 154
 155static int get_task_root(struct task_struct *task, struct path *root)
 156{
 157        int result = -ENOENT;
 158
 159        task_lock(task);
 160        if (task->fs) {
 161                get_fs_root(task->fs, root);
 162                result = 0;
 163        }
 164        task_unlock(task);
 165        return result;
 166}
 167
 168static int proc_cwd_link(struct inode *inode, struct path *path)
 169{
 170        struct task_struct *task = get_proc_task(inode);
 171        int result = -ENOENT;
 172
 173        if (task) {
 174                task_lock(task);
 175                if (task->fs) {
 176                        get_fs_pwd(task->fs, path);
 177                        result = 0;
 178                }
 179                task_unlock(task);
 180                put_task_struct(task);
 181        }
 182        return result;
 183}
 184
 185static int proc_root_link(struct inode *inode, struct path *path)
 186{
 187        struct task_struct *task = get_proc_task(inode);
 188        int result = -ENOENT;
 189
 190        if (task) {
 191                result = get_task_root(task, path);
 192                put_task_struct(task);
 193        }
 194        return result;
 195}
 196
 197static struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
 198{
 199        struct mm_struct *mm;
 200        int err;
 201
 202        err =  mutex_lock_killable(&task->signal->cred_guard_mutex);
 203        if (err)
 204                return ERR_PTR(err);
 205
 206        mm = get_task_mm(task);
 207        if (mm && mm != current->mm &&
 208                        !ptrace_may_access(task, mode)) {
 209                mmput(mm);
 210                mm = ERR_PTR(-EACCES);
 211        }
 212        mutex_unlock(&task->signal->cred_guard_mutex);
 213
 214        return mm;
 215}
 216
 217struct mm_struct *mm_for_maps(struct task_struct *task)
 218{
 219        return mm_access(task, PTRACE_MODE_READ);
 220}
 221
 222static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 223{
 224        int res = 0;
 225        unsigned int len;
 226        struct mm_struct *mm = get_task_mm(task);
 227        if (!mm)
 228                goto out;
 229        if (!mm->arg_end)
 230                goto out_mm;    /* Shh! No looking before we're done */
 231
 232        len = mm->arg_end - mm->arg_start;
 233 
 234        if (len > PAGE_SIZE)
 235                len = PAGE_SIZE;
 236 
 237        res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 238
 239        // If the nul at the end of args has been overwritten, then
 240        // assume application is using setproctitle(3).
 241        if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 242                len = strnlen(buffer, res);
 243                if (len < res) {
 244                    res = len;
 245                } else {
 246                        len = mm->env_end - mm->env_start;
 247                        if (len > PAGE_SIZE - res)
 248                                len = PAGE_SIZE - res;
 249                        res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 250                        res = strnlen(buffer, res);
 251                }
 252        }
 253out_mm:
 254        mmput(mm);
 255out:
 256        return res;
 257}
 258
 259static int proc_pid_auxv(struct task_struct *task, char *buffer)
 260{
 261        struct mm_struct *mm = mm_for_maps(task);
 262        int res = PTR_ERR(mm);
 263        if (mm && !IS_ERR(mm)) {
 264                unsigned int nwords = 0;
 265                do {
 266                        nwords += 2;
 267                } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 268                res = nwords * sizeof(mm->saved_auxv[0]);
 269                if (res > PAGE_SIZE)
 270                        res = PAGE_SIZE;
 271                memcpy(buffer, mm->saved_auxv, res);
 272                mmput(mm);
 273        }
 274        return res;
 275}
 276
 277
 278#ifdef CONFIG_KALLSYMS
 279/*
 280 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 281 * Returns the resolved symbol.  If that fails, simply return the address.
 282 */
 283static int proc_pid_wchan(struct task_struct *task, char *buffer)
 284{
 285        unsigned long wchan;
 286        char symname[KSYM_NAME_LEN];
 287
 288        wchan = get_wchan(task);
 289
 290        if (lookup_symbol_name(wchan, symname) < 0)
 291                if (!ptrace_may_access(task, PTRACE_MODE_READ))
 292                        return 0;
 293                else
 294                        return sprintf(buffer, "%lu", wchan);
 295        else
 296                return sprintf(buffer, "%s", symname);
 297}
 298#endif /* CONFIG_KALLSYMS */
 299
 300static int lock_trace(struct task_struct *task)
 301{
 302        int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 303        if (err)
 304                return err;
 305        if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
 306                mutex_unlock(&task->signal->cred_guard_mutex);
 307                return -EPERM;
 308        }
 309        return 0;
 310}
 311
 312static void unlock_trace(struct task_struct *task)
 313{
 314        mutex_unlock(&task->signal->cred_guard_mutex);
 315}
 316
 317#ifdef CONFIG_STACKTRACE
 318
 319#define MAX_STACK_TRACE_DEPTH   64
 320
 321static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 322                          struct pid *pid, struct task_struct *task)
 323{
 324        struct stack_trace trace;
 325        unsigned long *entries;
 326        int err;
 327        int i;
 328
 329        entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 330        if (!entries)
 331                return -ENOMEM;
 332
 333        trace.nr_entries        = 0;
 334        trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 335        trace.entries           = entries;
 336        trace.skip              = 0;
 337
 338        err = lock_trace(task);
 339        if (!err) {
 340                save_stack_trace_tsk(task, &trace);
 341
 342                for (i = 0; i < trace.nr_entries; i++) {
 343                        seq_printf(m, "[<%pK>] %pS\n",
 344                                   (void *)entries[i], (void *)entries[i]);
 345                }
 346                unlock_trace(task);
 347        }
 348        kfree(entries);
 349
 350        return err;
 351}
 352#endif
 353
 354#ifdef CONFIG_SCHEDSTATS
 355/*
 356 * Provides /proc/PID/schedstat
 357 */
 358static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 359{
 360        return sprintf(buffer, "%llu %llu %lu\n",
 361                        (unsigned long long)task->se.sum_exec_runtime,
 362                        (unsigned long long)task->sched_info.run_delay,
 363                        task->sched_info.pcount);
 364}
 365#endif
 366
 367#ifdef CONFIG_LATENCYTOP
 368static int lstats_show_proc(struct seq_file *m, void *v)
 369{
 370        int i;
 371        struct inode *inode = m->private;
 372        struct task_struct *task = get_proc_task(inode);
 373
 374        if (!task)
 375                return -ESRCH;
 376        seq_puts(m, "Latency Top version : v0.1\n");
 377        for (i = 0; i < 32; i++) {
 378                struct latency_record *lr = &task->latency_record[i];
 379                if (lr->backtrace[0]) {
 380                        int q;
 381                        seq_printf(m, "%i %li %li",
 382                                   lr->count, lr->time, lr->max);
 383                        for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 384                                unsigned long bt = lr->backtrace[q];
 385                                if (!bt)
 386                                        break;
 387                                if (bt == ULONG_MAX)
 388                                        break;
 389                                seq_printf(m, " %ps", (void *)bt);
 390                        }
 391                        seq_putc(m, '\n');
 392                }
 393
 394        }
 395        put_task_struct(task);
 396        return 0;
 397}
 398
 399static int lstats_open(struct inode *inode, struct file *file)
 400{
 401        return single_open(file, lstats_show_proc, inode);
 402}
 403
 404static ssize_t lstats_write(struct file *file, const char __user *buf,
 405                            size_t count, loff_t *offs)
 406{
 407        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 408
 409        if (!task)
 410                return -ESRCH;
 411        clear_all_latency_tracing(task);
 412        put_task_struct(task);
 413
 414        return count;
 415}
 416
 417static const struct file_operations proc_lstats_operations = {
 418        .open           = lstats_open,
 419        .read           = seq_read,
 420        .write          = lstats_write,
 421        .llseek         = seq_lseek,
 422        .release        = single_release,
 423};
 424
 425#endif
 426
 427static int proc_oom_score(struct task_struct *task, char *buffer)
 428{
 429        unsigned long points = 0;
 430
 431        read_lock(&tasklist_lock);
 432        if (pid_alive(task))
 433                points = oom_badness(task, NULL, NULL,
 434                                        totalram_pages + total_swap_pages);
 435        read_unlock(&tasklist_lock);
 436        return sprintf(buffer, "%lu\n", points);
 437}
 438
 439struct limit_names {
 440        char *name;
 441        char *unit;
 442};
 443
 444static const struct limit_names lnames[RLIM_NLIMITS] = {
 445        [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 446        [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 447        [RLIMIT_DATA] = {"Max data size", "bytes"},
 448        [RLIMIT_STACK] = {"Max stack size", "bytes"},
 449        [RLIMIT_CORE] = {"Max core file size", "bytes"},
 450        [RLIMIT_RSS] = {"Max resident set", "bytes"},
 451        [RLIMIT_NPROC] = {"Max processes", "processes"},
 452        [RLIMIT_NOFILE] = {"Max open files", "files"},
 453        [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 454        [RLIMIT_AS] = {"Max address space", "bytes"},
 455        [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 456        [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 457        [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 458        [RLIMIT_NICE] = {"Max nice priority", NULL},
 459        [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 460        [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 461};
 462
 463/* Display limits for a process */
 464static int proc_pid_limits(struct task_struct *task, char *buffer)
 465{
 466        unsigned int i;
 467        int count = 0;
 468        unsigned long flags;
 469        char *bufptr = buffer;
 470
 471        struct rlimit rlim[RLIM_NLIMITS];
 472
 473        if (!lock_task_sighand(task, &flags))
 474                return 0;
 475        memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 476        unlock_task_sighand(task, &flags);
 477
 478        /*
 479         * print the file header
 480         */
 481        count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
 482                        "Limit", "Soft Limit", "Hard Limit", "Units");
 483
 484        for (i = 0; i < RLIM_NLIMITS; i++) {
 485                if (rlim[i].rlim_cur == RLIM_INFINITY)
 486                        count += sprintf(&bufptr[count], "%-25s %-20s ",
 487                                         lnames[i].name, "unlimited");
 488                else
 489                        count += sprintf(&bufptr[count], "%-25s %-20lu ",
 490                                         lnames[i].name, rlim[i].rlim_cur);
 491
 492                if (rlim[i].rlim_max == RLIM_INFINITY)
 493                        count += sprintf(&bufptr[count], "%-20s ", "unlimited");
 494                else
 495                        count += sprintf(&bufptr[count], "%-20lu ",
 496                                         rlim[i].rlim_max);
 497
 498                if (lnames[i].unit)
 499                        count += sprintf(&bufptr[count], "%-10s\n",
 500                                         lnames[i].unit);
 501                else
 502                        count += sprintf(&bufptr[count], "\n");
 503        }
 504
 505        return count;
 506}
 507
 508#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 509static int proc_pid_syscall(struct task_struct *task, char *buffer)
 510{
 511        long nr;
 512        unsigned long args[6], sp, pc;
 513        int res = lock_trace(task);
 514        if (res)
 515                return res;
 516
 517        if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 518                res = sprintf(buffer, "running\n");
 519        else if (nr < 0)
 520                res = sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 521        else
 522                res = sprintf(buffer,
 523                       "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 524                       nr,
 525                       args[0], args[1], args[2], args[3], args[4], args[5],
 526                       sp, pc);
 527        unlock_trace(task);
 528        return res;
 529}
 530#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 531
 532/************************************************************************/
 533/*                       Here the fs part begins                        */
 534/************************************************************************/
 535
 536/* permission checks */
 537static int proc_fd_access_allowed(struct inode *inode)
 538{
 539        struct task_struct *task;
 540        int allowed = 0;
 541        /* Allow access to a task's file descriptors if it is us or we
 542         * may use ptrace attach to the process and find out that
 543         * information.
 544         */
 545        task = get_proc_task(inode);
 546        if (task) {
 547                allowed = ptrace_may_access(task, PTRACE_MODE_READ);
 548                put_task_struct(task);
 549        }
 550        return allowed;
 551}
 552
 553int proc_setattr(struct dentry *dentry, struct iattr *attr)
 554{
 555        int error;
 556        struct inode *inode = dentry->d_inode;
 557
 558        if (attr->ia_valid & ATTR_MODE)
 559                return -EPERM;
 560
 561        error = inode_change_ok(inode, attr);
 562        if (error)
 563                return error;
 564
 565        if ((attr->ia_valid & ATTR_SIZE) &&
 566            attr->ia_size != i_size_read(inode)) {
 567                error = vmtruncate(inode, attr->ia_size);
 568                if (error)
 569                        return error;
 570        }
 571
 572        setattr_copy(inode, attr);
 573        mark_inode_dirty(inode);
 574        return 0;
 575}
 576
 577static const struct inode_operations proc_def_inode_operations = {
 578        .setattr        = proc_setattr,
 579};
 580
 581static int mounts_open_common(struct inode *inode, struct file *file,
 582                              const struct seq_operations *op)
 583{
 584        struct task_struct *task = get_proc_task(inode);
 585        struct nsproxy *nsp;
 586        struct mnt_namespace *ns = NULL;
 587        struct path root;
 588        struct proc_mounts *p;
 589        int ret = -EINVAL;
 590
 591        if (task) {
 592                rcu_read_lock();
 593                nsp = task_nsproxy(task);
 594                if (nsp) {
 595                        ns = nsp->mnt_ns;
 596                        if (ns)
 597                                get_mnt_ns(ns);
 598                }
 599                rcu_read_unlock();
 600                if (ns && get_task_root(task, &root) == 0)
 601                        ret = 0;
 602                put_task_struct(task);
 603        }
 604
 605        if (!ns)
 606                goto err;
 607        if (ret)
 608                goto err_put_ns;
 609
 610        ret = -ENOMEM;
 611        p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
 612        if (!p)
 613                goto err_put_path;
 614
 615        file->private_data = &p->m;
 616        ret = seq_open(file, op);
 617        if (ret)
 618                goto err_free;
 619
 620        p->m.private = p;
 621        p->ns = ns;
 622        p->root = root;
 623        p->m.poll_event = ns->event;
 624
 625        return 0;
 626
 627 err_free:
 628        kfree(p);
 629 err_put_path:
 630        path_put(&root);
 631 err_put_ns:
 632        put_mnt_ns(ns);
 633 err:
 634        return ret;
 635}
 636
 637static int mounts_release(struct inode *inode, struct file *file)
 638{
 639        struct proc_mounts *p = file->private_data;
 640        path_put(&p->root);
 641        put_mnt_ns(p->ns);
 642        return seq_release(inode, file);
 643}
 644
 645static unsigned mounts_poll(struct file *file, poll_table *wait)
 646{
 647        struct proc_mounts *p = file->private_data;
 648        unsigned res = POLLIN | POLLRDNORM;
 649
 650        poll_wait(file, &p->ns->poll, wait);
 651        if (mnt_had_events(p))
 652                res |= POLLERR | POLLPRI;
 653
 654        return res;
 655}
 656
 657static int mounts_open(struct inode *inode, struct file *file)
 658{
 659        return mounts_open_common(inode, file, &mounts_op);
 660}
 661
 662static const struct file_operations proc_mounts_operations = {
 663        .open           = mounts_open,
 664        .read           = seq_read,
 665        .llseek         = seq_lseek,
 666        .release        = mounts_release,
 667        .poll           = mounts_poll,
 668};
 669
 670static int mountinfo_open(struct inode *inode, struct file *file)
 671{
 672        return mounts_open_common(inode, file, &mountinfo_op);
 673}
 674
 675static const struct file_operations proc_mountinfo_operations = {
 676        .open           = mountinfo_open,
 677        .read           = seq_read,
 678        .llseek         = seq_lseek,
 679        .release        = mounts_release,
 680        .poll           = mounts_poll,
 681};
 682
 683static int mountstats_open(struct inode *inode, struct file *file)
 684{
 685        return mounts_open_common(inode, file, &mountstats_op);
 686}
 687
 688static const struct file_operations proc_mountstats_operations = {
 689        .open           = mountstats_open,
 690        .read           = seq_read,
 691        .llseek         = seq_lseek,
 692        .release        = mounts_release,
 693};
 694
 695#define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 696
 697static ssize_t proc_info_read(struct file * file, char __user * buf,
 698                          size_t count, loff_t *ppos)
 699{
 700        struct inode * inode = file->f_path.dentry->d_inode;
 701        unsigned long page;
 702        ssize_t length;
 703        struct task_struct *task = get_proc_task(inode);
 704
 705        length = -ESRCH;
 706        if (!task)
 707                goto out_no_task;
 708
 709        if (count > PROC_BLOCK_SIZE)
 710                count = PROC_BLOCK_SIZE;
 711
 712        length = -ENOMEM;
 713        if (!(page = __get_free_page(GFP_TEMPORARY)))
 714                goto out;
 715
 716        length = PROC_I(inode)->op.proc_read(task, (char*)page);
 717
 718        if (length >= 0)
 719                length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 720        free_page(page);
 721out:
 722        put_task_struct(task);
 723out_no_task:
 724        return length;
 725}
 726
 727static const struct file_operations proc_info_file_operations = {
 728        .read           = proc_info_read,
 729        .llseek         = generic_file_llseek,
 730};
 731
 732static int proc_single_show(struct seq_file *m, void *v)
 733{
 734        struct inode *inode = m->private;
 735        struct pid_namespace *ns;
 736        struct pid *pid;
 737        struct task_struct *task;
 738        int ret;
 739
 740        ns = inode->i_sb->s_fs_info;
 741        pid = proc_pid(inode);
 742        task = get_pid_task(pid, PIDTYPE_PID);
 743        if (!task)
 744                return -ESRCH;
 745
 746        ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 747
 748        put_task_struct(task);
 749        return ret;
 750}
 751
 752static int proc_single_open(struct inode *inode, struct file *filp)
 753{
 754        return single_open(filp, proc_single_show, inode);
 755}
 756
 757static const struct file_operations proc_single_file_operations = {
 758        .open           = proc_single_open,
 759        .read           = seq_read,
 760        .llseek         = seq_lseek,
 761        .release        = single_release,
 762};
 763
 764static int mem_open(struct inode* inode, struct file* file)
 765{
 766        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 767        struct mm_struct *mm;
 768
 769        if (!task)
 770                return -ESRCH;
 771
 772        mm = mm_access(task, PTRACE_MODE_ATTACH);
 773        put_task_struct(task);
 774
 775        if (IS_ERR(mm))
 776                return PTR_ERR(mm);
 777
 778        if (mm) {
 779                /* ensure this mm_struct can't be freed */
 780                atomic_inc(&mm->mm_count);
 781                /* but do not pin its memory */
 782                mmput(mm);
 783        }
 784
 785        /* OK to pass negative loff_t, we can catch out-of-range */
 786        file->f_mode |= FMODE_UNSIGNED_OFFSET;
 787        file->private_data = mm;
 788
 789        return 0;
 790}
 791
 792static ssize_t mem_rw(struct file *file, char __user *buf,
 793                        size_t count, loff_t *ppos, int write)
 794{
 795        struct mm_struct *mm = file->private_data;
 796        unsigned long addr = *ppos;
 797        ssize_t copied;
 798        char *page;
 799
 800        if (!mm)
 801                return 0;
 802
 803        page = (char *)__get_free_page(GFP_TEMPORARY);
 804        if (!page)
 805                return -ENOMEM;
 806
 807        copied = 0;
 808        if (!atomic_inc_not_zero(&mm->mm_users))
 809                goto free;
 810
 811        while (count > 0) {
 812                int this_len = min_t(int, count, PAGE_SIZE);
 813
 814                if (write && copy_from_user(page, buf, this_len)) {
 815                        copied = -EFAULT;
 816                        break;
 817                }
 818
 819                this_len = access_remote_vm(mm, addr, page, this_len, write);
 820                if (!this_len) {
 821                        if (!copied)
 822                                copied = -EIO;
 823                        break;
 824                }
 825
 826                if (!write && copy_to_user(buf, page, this_len)) {
 827                        copied = -EFAULT;
 828                        break;
 829                }
 830
 831                buf += this_len;
 832                addr += this_len;
 833                copied += this_len;
 834                count -= this_len;
 835        }
 836        *ppos = addr;
 837
 838        mmput(mm);
 839free:
 840        free_page((unsigned long) page);
 841        return copied;
 842}
 843
 844static ssize_t mem_read(struct file *file, char __user *buf,
 845                        size_t count, loff_t *ppos)
 846{
 847        return mem_rw(file, buf, count, ppos, 0);
 848}
 849
 850static ssize_t mem_write(struct file *file, const char __user *buf,
 851                         size_t count, loff_t *ppos)
 852{
 853        return mem_rw(file, (char __user*)buf, count, ppos, 1);
 854}
 855
 856loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 857{
 858        switch (orig) {
 859        case 0:
 860                file->f_pos = offset;
 861                break;
 862        case 1:
 863                file->f_pos += offset;
 864                break;
 865        default:
 866                return -EINVAL;
 867        }
 868        force_successful_syscall_return();
 869        return file->f_pos;
 870}
 871
 872static int mem_release(struct inode *inode, struct file *file)
 873{
 874        struct mm_struct *mm = file->private_data;
 875        if (mm)
 876                mmdrop(mm);
 877        return 0;
 878}
 879
 880static const struct file_operations proc_mem_operations = {
 881        .llseek         = mem_lseek,
 882        .read           = mem_read,
 883        .write          = mem_write,
 884        .open           = mem_open,
 885        .release        = mem_release,
 886};
 887
 888static ssize_t environ_read(struct file *file, char __user *buf,
 889                        size_t count, loff_t *ppos)
 890{
 891        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 892        char *page;
 893        unsigned long src = *ppos;
 894        int ret = -ESRCH;
 895        struct mm_struct *mm;
 896
 897        if (!task)
 898                goto out_no_task;
 899
 900        ret = -ENOMEM;
 901        page = (char *)__get_free_page(GFP_TEMPORARY);
 902        if (!page)
 903                goto out;
 904
 905
 906        mm = mm_for_maps(task);
 907        ret = PTR_ERR(mm);
 908        if (!mm || IS_ERR(mm))
 909                goto out_free;
 910
 911        ret = 0;
 912        while (count > 0) {
 913                int this_len, retval, max_len;
 914
 915                this_len = mm->env_end - (mm->env_start + src);
 916
 917                if (this_len <= 0)
 918                        break;
 919
 920                max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 921                this_len = (this_len > max_len) ? max_len : this_len;
 922
 923                retval = access_process_vm(task, (mm->env_start + src),
 924                        page, this_len, 0);
 925
 926                if (retval <= 0) {
 927                        ret = retval;
 928                        break;
 929                }
 930
 931                if (copy_to_user(buf, page, retval)) {
 932                        ret = -EFAULT;
 933                        break;
 934                }
 935
 936                ret += retval;
 937                src += retval;
 938                buf += retval;
 939                count -= retval;
 940        }
 941        *ppos = src;
 942
 943        mmput(mm);
 944out_free:
 945        free_page((unsigned long) page);
 946out:
 947        put_task_struct(task);
 948out_no_task:
 949        return ret;
 950}
 951
 952static const struct file_operations proc_environ_operations = {
 953        .read           = environ_read,
 954        .llseek         = generic_file_llseek,
 955};
 956
 957static ssize_t oom_adjust_read(struct file *file, char __user *buf,
 958                                size_t count, loff_t *ppos)
 959{
 960        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 961        char buffer[PROC_NUMBUF];
 962        size_t len;
 963        int oom_adjust = OOM_DISABLE;
 964        unsigned long flags;
 965
 966        if (!task)
 967                return -ESRCH;
 968
 969        if (lock_task_sighand(task, &flags)) {
 970                oom_adjust = task->signal->oom_adj;
 971                unlock_task_sighand(task, &flags);
 972        }
 973
 974        put_task_struct(task);
 975
 976        len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
 977
 978        return simple_read_from_buffer(buf, count, ppos, buffer, len);
 979}
 980
 981static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 982                                size_t count, loff_t *ppos)
 983{
 984        struct task_struct *task;
 985        char buffer[PROC_NUMBUF];
 986        int oom_adjust;
 987        unsigned long flags;
 988        int err;
 989
 990        memset(buffer, 0, sizeof(buffer));
 991        if (count > sizeof(buffer) - 1)
 992                count = sizeof(buffer) - 1;
 993        if (copy_from_user(buffer, buf, count)) {
 994                err = -EFAULT;
 995                goto out;
 996        }
 997
 998        err = kstrtoint(strstrip(buffer), 0, &oom_adjust);
 999        if (err)
1000                goto out;
1001        if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
1002             oom_adjust != OOM_DISABLE) {
1003                err = -EINVAL;
1004                goto out;
1005        }
1006
1007        task = get_proc_task(file->f_path.dentry->d_inode);
1008        if (!task) {
1009                err = -ESRCH;
1010                goto out;
1011        }
1012
1013        task_lock(task);
1014        if (!task->mm) {
1015                err = -EINVAL;
1016                goto err_task_lock;
1017        }
1018
1019        if (!lock_task_sighand(task, &flags)) {
1020                err = -ESRCH;
1021                goto err_task_lock;
1022        }
1023
1024        if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
1025                err = -EACCES;
1026                goto err_sighand;
1027        }
1028
1029        /*
1030         * Warn that /proc/pid/oom_adj is deprecated, see
1031         * Documentation/feature-removal-schedule.txt.
1032         */
1033        printk_once(KERN_WARNING "%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1034                  current->comm, task_pid_nr(current), task_pid_nr(task),
1035                  task_pid_nr(task));
1036        task->signal->oom_adj = oom_adjust;
1037        /*
1038         * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1039         * value is always attainable.
1040         */
1041        if (task->signal->oom_adj == OOM_ADJUST_MAX)
1042                task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX;
1043        else
1044                task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
1045                                                                -OOM_DISABLE;
1046err_sighand:
1047        unlock_task_sighand(task, &flags);
1048err_task_lock:
1049        task_unlock(task);
1050        put_task_struct(task);
1051out:
1052        return err < 0 ? err : count;
1053}
1054
1055static const struct file_operations proc_oom_adjust_operations = {
1056        .read           = oom_adjust_read,
1057        .write          = oom_adjust_write,
1058        .llseek         = generic_file_llseek,
1059};
1060
1061static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1062                                        size_t count, loff_t *ppos)
1063{
1064        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1065        char buffer[PROC_NUMBUF];
1066        int oom_score_adj = OOM_SCORE_ADJ_MIN;
1067        unsigned long flags;
1068        size_t len;
1069
1070        if (!task)
1071                return -ESRCH;
1072        if (lock_task_sighand(task, &flags)) {
1073                oom_score_adj = task->signal->oom_score_adj;
1074                unlock_task_sighand(task, &flags);
1075        }
1076        put_task_struct(task);
1077        len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj);
1078        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1079}
1080
1081static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1082                                        size_t count, loff_t *ppos)
1083{
1084        struct task_struct *task;
1085        char buffer[PROC_NUMBUF];
1086        unsigned long flags;
1087        int oom_score_adj;
1088        int err;
1089
1090        memset(buffer, 0, sizeof(buffer));
1091        if (count > sizeof(buffer) - 1)
1092                count = sizeof(buffer) - 1;
1093        if (copy_from_user(buffer, buf, count)) {
1094                err = -EFAULT;
1095                goto out;
1096        }
1097
1098        err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1099        if (err)
1100                goto out;
1101        if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1102                        oom_score_adj > OOM_SCORE_ADJ_MAX) {
1103                err = -EINVAL;
1104                goto out;
1105        }
1106
1107        task = get_proc_task(file->f_path.dentry->d_inode);
1108        if (!task) {
1109                err = -ESRCH;
1110                goto out;
1111        }
1112
1113        task_lock(task);
1114        if (!task->mm) {
1115                err = -EINVAL;
1116                goto err_task_lock;
1117        }
1118
1119        if (!lock_task_sighand(task, &flags)) {
1120                err = -ESRCH;
1121                goto err_task_lock;
1122        }
1123
1124        if (oom_score_adj < task->signal->oom_score_adj_min &&
1125                        !capable(CAP_SYS_RESOURCE)) {
1126                err = -EACCES;
1127                goto err_sighand;
1128        }
1129
1130        task->signal->oom_score_adj = oom_score_adj;
1131        if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1132                task->signal->oom_score_adj_min = oom_score_adj;
1133        /*
1134         * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
1135         * always attainable.
1136         */
1137        if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1138                task->signal->oom_adj = OOM_DISABLE;
1139        else
1140                task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
1141                                                        OOM_SCORE_ADJ_MAX;
1142err_sighand:
1143        unlock_task_sighand(task, &flags);
1144err_task_lock:
1145        task_unlock(task);
1146        put_task_struct(task);
1147out:
1148        return err < 0 ? err : count;
1149}
1150
1151static const struct file_operations proc_oom_score_adj_operations = {
1152        .read           = oom_score_adj_read,
1153        .write          = oom_score_adj_write,
1154        .llseek         = default_llseek,
1155};
1156
1157#ifdef CONFIG_AUDITSYSCALL
1158#define TMPBUFLEN 21
1159static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1160                                  size_t count, loff_t *ppos)
1161{
1162        struct inode * inode = file->f_path.dentry->d_inode;
1163        struct task_struct *task = get_proc_task(inode);
1164        ssize_t length;
1165        char tmpbuf[TMPBUFLEN];
1166
1167        if (!task)
1168                return -ESRCH;
1169        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1170                                audit_get_loginuid(task));
1171        put_task_struct(task);
1172        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1173}
1174
1175static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1176                                   size_t count, loff_t *ppos)
1177{
1178        struct inode * inode = file->f_path.dentry->d_inode;
1179        char *page, *tmp;
1180        ssize_t length;
1181        uid_t loginuid;
1182
1183        if (!capable(CAP_AUDIT_CONTROL))
1184                return -EPERM;
1185
1186        rcu_read_lock();
1187        if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1188                rcu_read_unlock();
1189                return -EPERM;
1190        }
1191        rcu_read_unlock();
1192
1193        if (count >= PAGE_SIZE)
1194                count = PAGE_SIZE - 1;
1195
1196        if (*ppos != 0) {
1197                /* No partial writes. */
1198                return -EINVAL;
1199        }
1200        page = (char*)__get_free_page(GFP_TEMPORARY);
1201        if (!page)
1202                return -ENOMEM;
1203        length = -EFAULT;
1204        if (copy_from_user(page, buf, count))
1205                goto out_free_page;
1206
1207        page[count] = '\0';
1208        loginuid = simple_strtoul(page, &tmp, 10);
1209        if (tmp == page) {
1210                length = -EINVAL;
1211                goto out_free_page;
1212
1213        }
1214        length = audit_set_loginuid(current, loginuid);
1215        if (likely(length == 0))
1216                length = count;
1217
1218out_free_page:
1219        free_page((unsigned long) page);
1220        return length;
1221}
1222
1223static const struct file_operations proc_loginuid_operations = {
1224        .read           = proc_loginuid_read,
1225        .write          = proc_loginuid_write,
1226        .llseek         = generic_file_llseek,
1227};
1228
1229static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1230                                  size_t count, loff_t *ppos)
1231{
1232        struct inode * inode = file->f_path.dentry->d_inode;
1233        struct task_struct *task = get_proc_task(inode);
1234        ssize_t length;
1235        char tmpbuf[TMPBUFLEN];
1236
1237        if (!task)
1238                return -ESRCH;
1239        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1240                                audit_get_sessionid(task));
1241        put_task_struct(task);
1242        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1243}
1244
1245static const struct file_operations proc_sessionid_operations = {
1246        .read           = proc_sessionid_read,
1247        .llseek         = generic_file_llseek,
1248};
1249#endif
1250
1251#ifdef CONFIG_FAULT_INJECTION
1252static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1253                                      size_t count, loff_t *ppos)
1254{
1255        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1256        char buffer[PROC_NUMBUF];
1257        size_t len;
1258        int make_it_fail;
1259
1260        if (!task)
1261                return -ESRCH;
1262        make_it_fail = task->make_it_fail;
1263        put_task_struct(task);
1264
1265        len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1266
1267        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1268}
1269
1270static ssize_t proc_fault_inject_write(struct file * file,
1271                        const char __user * buf, size_t count, loff_t *ppos)
1272{
1273        struct task_struct *task;
1274        char buffer[PROC_NUMBUF], *end;
1275        int make_it_fail;
1276
1277        if (!capable(CAP_SYS_RESOURCE))
1278                return -EPERM;
1279        memset(buffer, 0, sizeof(buffer));
1280        if (count > sizeof(buffer) - 1)
1281                count = sizeof(buffer) - 1;
1282        if (copy_from_user(buffer, buf, count))
1283                return -EFAULT;
1284        make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
1285        if (*end)
1286                return -EINVAL;
1287        task = get_proc_task(file->f_dentry->d_inode);
1288        if (!task)
1289                return -ESRCH;
1290        task->make_it_fail = make_it_fail;
1291        put_task_struct(task);
1292
1293        return count;
1294}
1295
1296static const struct file_operations proc_fault_inject_operations = {
1297        .read           = proc_fault_inject_read,
1298        .write          = proc_fault_inject_write,
1299        .llseek         = generic_file_llseek,
1300};
1301#endif
1302
1303
1304#ifdef CONFIG_SCHED_DEBUG
1305/*
1306 * Print out various scheduling related per-task fields:
1307 */
1308static int sched_show(struct seq_file *m, void *v)
1309{
1310        struct inode *inode = m->private;
1311        struct task_struct *p;
1312
1313        p = get_proc_task(inode);
1314        if (!p)
1315                return -ESRCH;
1316        proc_sched_show_task(p, m);
1317
1318        put_task_struct(p);
1319
1320        return 0;
1321}
1322
1323static ssize_t
1324sched_write(struct file *file, const char __user *buf,
1325            size_t count, loff_t *offset)
1326{
1327        struct inode *inode = file->f_path.dentry->d_inode;
1328        struct task_struct *p;
1329
1330        p = get_proc_task(inode);
1331        if (!p)
1332                return -ESRCH;
1333        proc_sched_set_task(p);
1334
1335        put_task_struct(p);
1336
1337        return count;
1338}
1339
1340static int sched_open(struct inode *inode, struct file *filp)
1341{
1342        return single_open(filp, sched_show, inode);
1343}
1344
1345static const struct file_operations proc_pid_sched_operations = {
1346        .open           = sched_open,
1347        .read           = seq_read,
1348        .write          = sched_write,
1349        .llseek         = seq_lseek,
1350        .release        = single_release,
1351};
1352
1353#endif
1354
1355#ifdef CONFIG_SCHED_AUTOGROUP
1356/*
1357 * Print out autogroup related information:
1358 */
1359static int sched_autogroup_show(struct seq_file *m, void *v)
1360{
1361        struct inode *inode = m->private;
1362        struct task_struct *p;
1363
1364        p = get_proc_task(inode);
1365        if (!p)
1366                return -ESRCH;
1367        proc_sched_autogroup_show_task(p, m);
1368
1369        put_task_struct(p);
1370
1371        return 0;
1372}
1373
1374static ssize_t
1375sched_autogroup_write(struct file *file, const char __user *buf,
1376            size_t count, loff_t *offset)
1377{
1378        struct inode *inode = file->f_path.dentry->d_inode;
1379        struct task_struct *p;
1380        char buffer[PROC_NUMBUF];
1381        int nice;
1382        int err;
1383
1384        memset(buffer, 0, sizeof(buffer));
1385        if (count > sizeof(buffer) - 1)
1386                count = sizeof(buffer) - 1;
1387        if (copy_from_user(buffer, buf, count))
1388                return -EFAULT;
1389
1390        err = kstrtoint(strstrip(buffer), 0, &nice);
1391        if (err < 0)
1392                return err;
1393
1394        p = get_proc_task(inode);
1395        if (!p)
1396                return -ESRCH;
1397
1398        err = nice;
1399        err = proc_sched_autogroup_set_nice(p, &err);
1400        if (err)
1401                count = err;
1402
1403        put_task_struct(p);
1404
1405        return count;
1406}
1407
1408static int sched_autogroup_open(struct inode *inode, struct file *filp)
1409{
1410        int ret;
1411
1412        ret = single_open(filp, sched_autogroup_show, NULL);
1413        if (!ret) {
1414                struct seq_file *m = filp->private_data;
1415
1416                m->private = inode;
1417        }
1418        return ret;
1419}
1420
1421static const struct file_operations proc_pid_sched_autogroup_operations = {
1422        .open           = sched_autogroup_open,
1423        .read           = seq_read,
1424        .write          = sched_autogroup_write,
1425        .llseek         = seq_lseek,
1426        .release        = single_release,
1427};
1428
1429#endif /* CONFIG_SCHED_AUTOGROUP */
1430
1431static ssize_t comm_write(struct file *file, const char __user *buf,
1432                                size_t count, loff_t *offset)
1433{
1434        struct inode *inode = file->f_path.dentry->d_inode;
1435        struct task_struct *p;
1436        char buffer[TASK_COMM_LEN];
1437
1438        memset(buffer, 0, sizeof(buffer));
1439        if (count > sizeof(buffer) - 1)
1440                count = sizeof(buffer) - 1;
1441        if (copy_from_user(buffer, buf, count))
1442                return -EFAULT;
1443
1444        p = get_proc_task(inode);
1445        if (!p)
1446                return -ESRCH;
1447
1448        if (same_thread_group(current, p))
1449                set_task_comm(p, buffer);
1450        else
1451                count = -EINVAL;
1452
1453        put_task_struct(p);
1454
1455        return count;
1456}
1457
1458static int comm_show(struct seq_file *m, void *v)
1459{
1460        struct inode *inode = m->private;
1461        struct task_struct *p;
1462
1463        p = get_proc_task(inode);
1464        if (!p)
1465                return -ESRCH;
1466
1467        task_lock(p);
1468        seq_printf(m, "%s\n", p->comm);
1469        task_unlock(p);
1470
1471        put_task_struct(p);
1472
1473        return 0;
1474}
1475
1476static int comm_open(struct inode *inode, struct file *filp)
1477{
1478        return single_open(filp, comm_show, inode);
1479}
1480
1481static const struct file_operations proc_pid_set_comm_operations = {
1482        .open           = comm_open,
1483        .read           = seq_read,
1484        .write          = comm_write,
1485        .llseek         = seq_lseek,
1486        .release        = single_release,
1487};
1488
1489static int proc_exe_link(struct inode *inode, struct path *exe_path)
1490{
1491        struct task_struct *task;
1492        struct mm_struct *mm;
1493        struct file *exe_file;
1494
1495        task = get_proc_task(inode);
1496        if (!task)
1497                return -ENOENT;
1498        mm = get_task_mm(task);
1499        put_task_struct(task);
1500        if (!mm)
1501                return -ENOENT;
1502        exe_file = get_mm_exe_file(mm);
1503        mmput(mm);
1504        if (exe_file) {
1505                *exe_path = exe_file->f_path;
1506                path_get(&exe_file->f_path);
1507                fput(exe_file);
1508                return 0;
1509        } else
1510                return -ENOENT;
1511}
1512
1513static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1514{
1515        struct inode *inode = dentry->d_inode;
1516        int error = -EACCES;
1517
1518        /* We don't need a base pointer in the /proc filesystem */
1519        path_put(&nd->path);
1520
1521        /* Are we allowed to snoop on the tasks file descriptors? */
1522        if (!proc_fd_access_allowed(inode))
1523                goto out;
1524
1525        error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1526out:
1527        return ERR_PTR(error);
1528}
1529
1530static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1531{
1532        char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1533        char *pathname;
1534        int len;
1535
1536        if (!tmp)
1537                return -ENOMEM;
1538
1539        pathname = d_path(path, tmp, PAGE_SIZE);
1540        len = PTR_ERR(pathname);
1541        if (IS_ERR(pathname))
1542                goto out;
1543        len = tmp + PAGE_SIZE - 1 - pathname;
1544
1545        if (len > buflen)
1546                len = buflen;
1547        if (copy_to_user(buffer, pathname, len))
1548                len = -EFAULT;
1549 out:
1550        free_page((unsigned long)tmp);
1551        return len;
1552}
1553
1554static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1555{
1556        int error = -EACCES;
1557        struct inode *inode = dentry->d_inode;
1558        struct path path;
1559
1560        /* Are we allowed to snoop on the tasks file descriptors? */
1561        if (!proc_fd_access_allowed(inode))
1562                goto out;
1563
1564        error = PROC_I(inode)->op.proc_get_link(inode, &path);
1565        if (error)
1566                goto out;
1567
1568        error = do_proc_readlink(&path, buffer, buflen);
1569        path_put(&path);
1570out:
1571        return error;
1572}
1573
1574static const struct inode_operations proc_pid_link_inode_operations = {
1575        .readlink       = proc_pid_readlink,
1576        .follow_link    = proc_pid_follow_link,
1577        .setattr        = proc_setattr,
1578};
1579
1580
1581/* building an inode */
1582
1583static int task_dumpable(struct task_struct *task)
1584{
1585        int dumpable = 0;
1586        struct mm_struct *mm;
1587
1588        task_lock(task);
1589        mm = task->mm;
1590        if (mm)
1591                dumpable = get_dumpable(mm);
1592        task_unlock(task);
1593        if(dumpable == 1)
1594                return 1;
1595        return 0;
1596}
1597
1598struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1599{
1600        struct inode * inode;
1601        struct proc_inode *ei;
1602        const struct cred *cred;
1603
1604        /* We need a new inode */
1605
1606        inode = new_inode(sb);
1607        if (!inode)
1608                goto out;
1609
1610        /* Common stuff */
1611        ei = PROC_I(inode);
1612        inode->i_ino = get_next_ino();
1613        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1614        inode->i_op = &proc_def_inode_operations;
1615
1616        /*
1617         * grab the reference to task.
1618         */
1619        ei->pid = get_task_pid(task, PIDTYPE_PID);
1620        if (!ei->pid)
1621                goto out_unlock;
1622
1623        if (task_dumpable(task)) {
1624                rcu_read_lock();
1625                cred = __task_cred(task);
1626                inode->i_uid = cred->euid;
1627                inode->i_gid = cred->egid;
1628                rcu_read_unlock();
1629        }
1630        security_task_to_inode(task, inode);
1631
1632out:
1633        return inode;
1634
1635out_unlock:
1636        iput(inode);
1637        return NULL;
1638}
1639
1640int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1641{
1642        struct inode *inode = dentry->d_inode;
1643        struct task_struct *task;
1644        const struct cred *cred;
1645
1646        generic_fillattr(inode, stat);
1647
1648        rcu_read_lock();
1649        stat->uid = 0;
1650        stat->gid = 0;
1651        task = pid_task(proc_pid(inode), PIDTYPE_PID);
1652        if (task) {
1653                if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1654                    task_dumpable(task)) {
1655                        cred = __task_cred(task);
1656                        stat->uid = cred->euid;
1657                        stat->gid = cred->egid;
1658                }
1659        }
1660        rcu_read_unlock();
1661        return 0;
1662}
1663
1664/* dentry stuff */
1665
1666/*
1667 *      Exceptional case: normally we are not allowed to unhash a busy
1668 * directory. In this case, however, we can do it - no aliasing problems
1669 * due to the way we treat inodes.
1670 *
1671 * Rewrite the inode's ownerships here because the owning task may have
1672 * performed a setuid(), etc.
1673 *
1674 * Before the /proc/pid/status file was created the only way to read
1675 * the effective uid of a /process was to stat /proc/pid.  Reading
1676 * /proc/pid/status is slow enough that procps and other packages
1677 * kept stating /proc/pid.  To keep the rules in /proc simple I have
1678 * made this apply to all per process world readable and executable
1679 * directories.
1680 */
1681int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1682{
1683        struct inode *inode;
1684        struct task_struct *task;
1685        const struct cred *cred;
1686
1687        if (nd && nd->flags & LOOKUP_RCU)
1688                return -ECHILD;
1689
1690        inode = dentry->d_inode;
1691        task = get_proc_task(inode);
1692
1693        if (task) {
1694                if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1695                    task_dumpable(task)) {
1696                        rcu_read_lock();
1697                        cred = __task_cred(task);
1698                        inode->i_uid = cred->euid;
1699                        inode->i_gid = cred->egid;
1700                        rcu_read_unlock();
1701                } else {
1702                        inode->i_uid = 0;
1703                        inode->i_gid = 0;
1704                }
1705                inode->i_mode &= ~(S_ISUID | S_ISGID);
1706                security_task_to_inode(task, inode);
1707                put_task_struct(task);
1708                return 1;
1709        }
1710        d_drop(dentry);
1711        return 0;
1712}
1713
1714static int pid_delete_dentry(const struct dentry * dentry)
1715{
1716        /* Is the task we represent dead?
1717         * If so, then don't put the dentry on the lru list,
1718         * kill it immediately.
1719         */
1720        return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1721}
1722
1723const struct dentry_operations pid_dentry_operations =
1724{
1725        .d_revalidate   = pid_revalidate,
1726        .d_delete       = pid_delete_dentry,
1727};
1728
1729/* Lookups */
1730
1731/*
1732 * Fill a directory entry.
1733 *
1734 * If possible create the dcache entry and derive our inode number and
1735 * file type from dcache entry.
1736 *
1737 * Since all of the proc inode numbers are dynamically generated, the inode
1738 * numbers do not exist until the inode is cache.  This means creating the
1739 * the dcache entry in readdir is necessary to keep the inode numbers
1740 * reported by readdir in sync with the inode numbers reported
1741 * by stat.
1742 */
1743int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1744        const char *name, int len,
1745        instantiate_t instantiate, struct task_struct *task, const void *ptr)
1746{
1747        struct dentry *child, *dir = filp->f_path.dentry;
1748        struct inode *inode;
1749        struct qstr qname;
1750        ino_t ino = 0;
1751        unsigned type = DT_UNKNOWN;
1752
1753        qname.name = name;
1754        qname.len  = len;
1755        qname.hash = full_name_hash(name, len);
1756
1757        child = d_lookup(dir, &qname);
1758        if (!child) {
1759                struct dentry *new;
1760                new = d_alloc(dir, &qname);
1761                if (new) {
1762                        child = instantiate(dir->d_inode, new, task, ptr);
1763                        if (child)
1764                                dput(new);
1765                        else
1766                                child = new;
1767                }
1768        }
1769        if (!child || IS_ERR(child) || !child->d_inode)
1770                goto end_instantiate;
1771        inode = child->d_inode;
1772        if (inode) {
1773                ino = inode->i_ino;
1774                type = inode->i_mode >> 12;
1775        }
1776        dput(child);
1777end_instantiate:
1778        if (!ino)
1779                ino = find_inode_number(dir, &qname);
1780        if (!ino)
1781                ino = 1;
1782        return filldir(dirent, name, len, filp->f_pos, ino, type);
1783}
1784
1785static unsigned name_to_int(struct dentry *dentry)
1786{
1787        const char *name = dentry->d_name.name;
1788        int len = dentry->d_name.len;
1789        unsigned n = 0;
1790
1791        if (len > 1 && *name == '0')
1792                goto out;
1793        while (len-- > 0) {
1794                unsigned c = *name++ - '0';
1795                if (c > 9)
1796                        goto out;
1797                if (n >= (~0U-9)/10)
1798                        goto out;
1799                n *= 10;
1800                n += c;
1801        }
1802        return n;
1803out:
1804        return ~0U;
1805}
1806
1807#define PROC_FDINFO_MAX 64
1808
1809static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1810{
1811        struct task_struct *task = get_proc_task(inode);
1812        struct files_struct *files = NULL;
1813        struct file *file;
1814        int fd = proc_fd(inode);
1815
1816        if (task) {
1817                files = get_files_struct(task);
1818                put_task_struct(task);
1819        }
1820        if (files) {
1821                /*
1822                 * We are not taking a ref to the file structure, so we must
1823                 * hold ->file_lock.
1824                 */
1825                spin_lock(&files->file_lock);
1826                file = fcheck_files(files, fd);
1827                if (file) {
1828                        unsigned int f_flags;
1829                        struct fdtable *fdt;
1830
1831                        fdt = files_fdtable(files);
1832                        f_flags = file->f_flags & ~O_CLOEXEC;
1833                        if (FD_ISSET(fd, fdt->close_on_exec))
1834                                f_flags |= O_CLOEXEC;
1835
1836                        if (path) {
1837                                *path = file->f_path;
1838                                path_get(&file->f_path);
1839                        }
1840                        if (info)
1841                                snprintf(info, PROC_FDINFO_MAX,
1842                                         "pos:\t%lli\n"
1843                                         "flags:\t0%o\n",
1844                                         (long long) file->f_pos,
1845                                         f_flags);
1846                        spin_unlock(&files->file_lock);
1847                        put_files_struct(files);
1848                        return 0;
1849                }
1850                spin_unlock(&files->file_lock);
1851                put_files_struct(files);
1852        }
1853        return -ENOENT;
1854}
1855
1856static int proc_fd_link(struct inode *inode, struct path *path)
1857{
1858        return proc_fd_info(inode, path, NULL);
1859}
1860
1861static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1862{
1863        struct inode *inode;
1864        struct task_struct *task;
1865        int fd;
1866        struct files_struct *files;
1867        const struct cred *cred;
1868
1869        if (nd && nd->flags & LOOKUP_RCU)
1870                return -ECHILD;
1871
1872        inode = dentry->d_inode;
1873        task = get_proc_task(inode);
1874        fd = proc_fd(inode);
1875
1876        if (task) {
1877                files = get_files_struct(task);
1878                if (files) {
1879                        rcu_read_lock();
1880                        if (fcheck_files(files, fd)) {
1881                                rcu_read_unlock();
1882                                put_files_struct(files);
1883                                if (task_dumpable(task)) {
1884                                        rcu_read_lock();
1885                                        cred = __task_cred(task);
1886                                        inode->i_uid = cred->euid;
1887                                        inode->i_gid = cred->egid;
1888                                        rcu_read_unlock();
1889                                } else {
1890                                        inode->i_uid = 0;
1891                                        inode->i_gid = 0;
1892                                }
1893                                inode->i_mode &= ~(S_ISUID | S_ISGID);
1894                                security_task_to_inode(task, inode);
1895                                put_task_struct(task);
1896                                return 1;
1897                        }
1898                        rcu_read_unlock();
1899                        put_files_struct(files);
1900                }
1901                put_task_struct(task);
1902        }
1903        d_drop(dentry);
1904        return 0;
1905}
1906
1907static const struct dentry_operations tid_fd_dentry_operations =
1908{
1909        .d_revalidate   = tid_fd_revalidate,
1910        .d_delete       = pid_delete_dentry,
1911};
1912
1913static struct dentry *proc_fd_instantiate(struct inode *dir,
1914        struct dentry *dentry, struct task_struct *task, const void *ptr)
1915{
1916        unsigned fd = *(const unsigned *)ptr;
1917        struct file *file;
1918        struct files_struct *files;
1919        struct inode *inode;
1920        struct proc_inode *ei;
1921        struct dentry *error = ERR_PTR(-ENOENT);
1922
1923        inode = proc_pid_make_inode(dir->i_sb, task);
1924        if (!inode)
1925                goto out;
1926        ei = PROC_I(inode);
1927        ei->fd = fd;
1928        files = get_files_struct(task);
1929        if (!files)
1930                goto out_iput;
1931        inode->i_mode = S_IFLNK;
1932
1933        /*
1934         * We are not taking a ref to the file structure, so we must
1935         * hold ->file_lock.
1936         */
1937        spin_lock(&files->file_lock);
1938        file = fcheck_files(files, fd);
1939        if (!file)
1940                goto out_unlock;
1941        if (file->f_mode & FMODE_READ)
1942                inode->i_mode |= S_IRUSR | S_IXUSR;
1943        if (file->f_mode & FMODE_WRITE)
1944                inode->i_mode |= S_IWUSR | S_IXUSR;
1945        spin_unlock(&files->file_lock);
1946        put_files_struct(files);
1947
1948        inode->i_op = &proc_pid_link_inode_operations;
1949        inode->i_size = 64;
1950        ei->op.proc_get_link = proc_fd_link;
1951        d_set_d_op(dentry, &tid_fd_dentry_operations);
1952        d_add(dentry, inode);
1953        /* Close the race of the process dying before we return the dentry */
1954        if (tid_fd_revalidate(dentry, NULL))
1955                error = NULL;
1956
1957 out:
1958        return error;
1959out_unlock:
1960        spin_unlock(&files->file_lock);
1961        put_files_struct(files);
1962out_iput:
1963        iput(inode);
1964        goto out;
1965}
1966
1967static struct dentry *proc_lookupfd_common(struct inode *dir,
1968                                           struct dentry *dentry,
1969                                           instantiate_t instantiate)
1970{
1971        struct task_struct *task = get_proc_task(dir);
1972        unsigned fd = name_to_int(dentry);
1973        struct dentry *result = ERR_PTR(-ENOENT);
1974
1975        if (!task)
1976                goto out_no_task;
1977        if (fd == ~0U)
1978                goto out;
1979
1980        result = instantiate(dir, dentry, task, &fd);
1981out:
1982        put_task_struct(task);
1983out_no_task:
1984        return result;
1985}
1986
1987static int proc_readfd_common(struct file * filp, void * dirent,
1988                              filldir_t filldir, instantiate_t instantiate)
1989{
1990        struct dentry *dentry = filp->f_path.dentry;
1991        struct inode *inode = dentry->d_inode;
1992        struct task_struct *p = get_proc_task(inode);
1993        unsigned int fd, ino;
1994        int retval;
1995        struct files_struct * files;
1996
1997        retval = -ENOENT;
1998        if (!p)
1999                goto out_no_task;
2000        retval = 0;
2001
2002        fd = filp->f_pos;
2003        switch (fd) {
2004                case 0:
2005                        if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
2006                                goto out;
2007                        filp->f_pos++;
2008                case 1:
2009                        ino = parent_ino(dentry);
2010                        if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
2011                                goto out;
2012                        filp->f_pos++;
2013                default:
2014                        files = get_files_struct(p);
2015                        if (!files)
2016                                goto out;
2017                        rcu_read_lock();
2018                        for (fd = filp->f_pos-2;
2019                             fd < files_fdtable(files)->max_fds;
2020                             fd++, filp->f_pos++) {
2021                                char name[PROC_NUMBUF];
2022                                int len;
2023
2024                                if (!fcheck_files(files, fd))
2025                                        continue;
2026                                rcu_read_unlock();
2027
2028                                len = snprintf(name, sizeof(name), "%d", fd);
2029                                if (proc_fill_cache(filp, dirent, filldir,
2030                                                    name, len, instantiate,
2031                                                    p, &fd) < 0) {
2032                                        rcu_read_lock();
2033                                        break;
2034                                }
2035                                rcu_read_lock();
2036                        }
2037                        rcu_read_unlock();
2038                        put_files_struct(files);
2039        }
2040out:
2041        put_task_struct(p);
2042out_no_task:
2043        return retval;
2044}
2045
2046static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
2047                                    struct nameidata *nd)
2048{
2049        return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
2050}
2051
2052static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
2053{
2054        return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
2055}
2056
2057static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
2058                                      size_t len, loff_t *ppos)
2059{
2060        char tmp[PROC_FDINFO_MAX];
2061        int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
2062        if (!err)
2063                err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
2064        return err;
2065}
2066
2067static const struct file_operations proc_fdinfo_file_operations = {
2068        .open           = nonseekable_open,
2069        .read           = proc_fdinfo_read,
2070        .llseek         = no_llseek,
2071};
2072
2073static const struct file_operations proc_fd_operations = {
2074        .read           = generic_read_dir,
2075        .readdir        = proc_readfd,
2076        .llseek         = default_llseek,
2077};
2078
2079/*
2080 * /proc/pid/fd needs a special permission handler so that a process can still
2081 * access /proc/self/fd after it has executed a setuid().
2082 */
2083static int proc_fd_permission(struct inode *inode, int mask)
2084{
2085        int rv = generic_permission(inode, mask);
2086        if (rv == 0)
2087                return 0;
2088        if (task_pid(current) == proc_pid(inode))
2089                rv = 0;
2090        return rv;
2091}
2092
2093/*
2094 * proc directories can do almost nothing..
2095 */
2096static const struct inode_operations proc_fd_inode_operations = {
2097        .lookup         = proc_lookupfd,
2098        .permission     = proc_fd_permission,
2099        .setattr        = proc_setattr,
2100};
2101
2102static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
2103        struct dentry *dentry, struct task_struct *task, const void *ptr)
2104{
2105        unsigned fd = *(unsigned *)ptr;
2106        struct inode *inode;
2107        struct proc_inode *ei;
2108        struct dentry *error = ERR_PTR(-ENOENT);
2109
2110        inode = proc_pid_make_inode(dir->i_sb, task);
2111        if (!inode)
2112                goto out;
2113        ei = PROC_I(inode);
2114        ei->fd = fd;
2115        inode->i_mode = S_IFREG | S_IRUSR;
2116        inode->i_fop = &proc_fdinfo_file_operations;
2117        d_set_d_op(dentry, &tid_fd_dentry_operations);
2118        d_add(dentry, inode);
2119        /* Close the race of the process dying before we return the dentry */
2120        if (tid_fd_revalidate(dentry, NULL))
2121                error = NULL;
2122
2123 out:
2124        return error;
2125}
2126
2127static struct dentry *proc_lookupfdinfo(struct inode *dir,
2128                                        struct dentry *dentry,
2129                                        struct nameidata *nd)
2130{
2131        return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
2132}
2133
2134static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
2135{
2136        return proc_readfd_common(filp, dirent, filldir,
2137                                  proc_fdinfo_instantiate);
2138}
2139
2140static const struct file_operations proc_fdinfo_operations = {
2141        .read           = generic_read_dir,
2142        .readdir        = proc_readfdinfo,
2143        .llseek         = default_llseek,
2144};
2145
2146/*
2147 * proc directories can do almost nothing..
2148 */
2149static const struct inode_operations proc_fdinfo_inode_operations = {
2150        .lookup         = proc_lookupfdinfo,
2151        .setattr        = proc_setattr,
2152};
2153
2154
2155static struct dentry *proc_pident_instantiate(struct inode *dir,
2156        struct dentry *dentry, struct task_struct *task, const void *ptr)
2157{
2158        const struct pid_entry *p = ptr;
2159        struct inode *inode;
2160        struct proc_inode *ei;
2161        struct dentry *error = ERR_PTR(-ENOENT);
2162
2163        inode = proc_pid_make_inode(dir->i_sb, task);
2164        if (!inode)
2165                goto out;
2166
2167        ei = PROC_I(inode);
2168        inode->i_mode = p->mode;
2169        if (S_ISDIR(inode->i_mode))
2170                set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2171        if (p->iop)
2172                inode->i_op = p->iop;
2173        if (p->fop)
2174                inode->i_fop = p->fop;
2175        ei->op = p->op;
2176        d_set_d_op(dentry, &pid_dentry_operations);
2177        d_add(dentry, inode);
2178        /* Close the race of the process dying before we return the dentry */
2179        if (pid_revalidate(dentry, NULL))
2180                error = NULL;
2181out:
2182        return error;
2183}
2184
2185static struct dentry *proc_pident_lookup(struct inode *dir, 
2186                                         struct dentry *dentry,
2187                                         const struct pid_entry *ents,
2188                                         unsigned int nents)
2189{
2190        struct dentry *error;
2191        struct task_struct *task = get_proc_task(dir);
2192        const struct pid_entry *p, *last;
2193
2194        error = ERR_PTR(-ENOENT);
2195
2196        if (!task)
2197                goto out_no_task;
2198
2199        /*
2200         * Yes, it does not scale. And it should not. Don't add
2201         * new entries into /proc/<tgid>/ without very good reasons.
2202         */
2203        last = &ents[nents - 1];
2204        for (p = ents; p <= last; p++) {
2205                if (p->len != dentry->d_name.len)
2206                        continue;
2207                if (!memcmp(dentry->d_name.name, p->name, p->len))
2208                        break;
2209        }
2210        if (p > last)
2211                goto out;
2212
2213        error = proc_pident_instantiate(dir, dentry, task, p);
2214out:
2215        put_task_struct(task);
2216out_no_task:
2217        return error;
2218}
2219
2220static int proc_pident_fill_cache(struct file *filp, void *dirent,
2221        filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2222{
2223        return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2224                                proc_pident_instantiate, task, p);
2225}
2226
2227static int proc_pident_readdir(struct file *filp,
2228                void *dirent, filldir_t filldir,
2229                const struct pid_entry *ents, unsigned int nents)
2230{
2231        int i;
2232        struct dentry *dentry = filp->f_path.dentry;
2233        struct inode *inode = dentry->d_inode;
2234        struct task_struct *task = get_proc_task(inode);
2235        const struct pid_entry *p, *last;
2236        ino_t ino;
2237        int ret;
2238
2239        ret = -ENOENT;
2240        if (!task)
2241                goto out_no_task;
2242
2243        ret = 0;
2244        i = filp->f_pos;
2245        switch (i) {
2246        case 0:
2247                ino = inode->i_ino;
2248                if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2249                        goto out;
2250                i++;
2251                filp->f_pos++;
2252                /* fall through */
2253        case 1:
2254                ino = parent_ino(dentry);
2255                if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2256                        goto out;
2257                i++;
2258                filp->f_pos++;
2259                /* fall through */
2260        default:
2261                i -= 2;
2262                if (i >= nents) {
2263                        ret = 1;
2264                        goto out;
2265                }
2266                p = ents + i;
2267                last = &ents[nents - 1];
2268                while (p <= last) {
2269                        if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2270                                goto out;
2271                        filp->f_pos++;
2272                        p++;
2273                }
2274        }
2275
2276        ret = 1;
2277out:
2278        put_task_struct(task);
2279out_no_task:
2280        return ret;
2281}
2282
2283#ifdef CONFIG_SECURITY
2284static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2285                                  size_t count, loff_t *ppos)
2286{
2287        struct inode * inode = file->f_path.dentry->d_inode;
2288        char *p = NULL;
2289        ssize_t length;
2290        struct task_struct *task = get_proc_task(inode);
2291
2292        if (!task)
2293                return -ESRCH;
2294
2295        length = security_getprocattr(task,
2296                                      (char*)file->f_path.dentry->d_name.name,
2297                                      &p);
2298        put_task_struct(task);
2299        if (length > 0)
2300                length = simple_read_from_buffer(buf, count, ppos, p, length);
2301        kfree(p);
2302        return length;
2303}
2304
2305static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2306                                   size_t count, loff_t *ppos)
2307{
2308        struct inode * inode = file->f_path.dentry->d_inode;
2309        char *page;
2310        ssize_t length;
2311        struct task_struct *task = get_proc_task(inode);
2312
2313        length = -ESRCH;
2314        if (!task)
2315                goto out_no_task;
2316        if (count > PAGE_SIZE)
2317                count = PAGE_SIZE;
2318
2319        /* No partial writes. */
2320        length = -EINVAL;
2321        if (*ppos != 0)
2322                goto out;
2323
2324        length = -ENOMEM;
2325        page = (char*)__get_free_page(GFP_TEMPORARY);
2326        if (!page)
2327                goto out;
2328
2329        length = -EFAULT;
2330        if (copy_from_user(page, buf, count))
2331                goto out_free;
2332
2333        /* Guard against adverse ptrace interaction */
2334        length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2335        if (length < 0)
2336                goto out_free;
2337
2338        length = security_setprocattr(task,
2339                                      (char*)file->f_path.dentry->d_name.name,
2340                                      (void*)page, count);
2341        mutex_unlock(&task->signal->cred_guard_mutex);
2342out_free:
2343        free_page((unsigned long) page);
2344out:
2345        put_task_struct(task);
2346out_no_task:
2347        return length;
2348}
2349
2350static const struct file_operations proc_pid_attr_operations = {
2351        .read           = proc_pid_attr_read,
2352        .write          = proc_pid_attr_write,
2353        .llseek         = generic_file_llseek,
2354};
2355
2356static const struct pid_entry attr_dir_stuff[] = {
2357        REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2358        REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2359        REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2360        REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2361        REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2362        REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2363};
2364
2365static int proc_attr_dir_readdir(struct file * filp,
2366                             void * dirent, filldir_t filldir)
2367{
2368        return proc_pident_readdir(filp,dirent,filldir,
2369                                   attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2370}
2371
2372static const struct file_operations proc_attr_dir_operations = {
2373        .read           = generic_read_dir,
2374        .readdir        = proc_attr_dir_readdir,
2375        .llseek         = default_llseek,
2376};
2377
2378static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2379                                struct dentry *dentry, struct nameidata *nd)
2380{
2381        return proc_pident_lookup(dir, dentry,
2382                                  attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2383}
2384
2385static const struct inode_operations proc_attr_dir_inode_operations = {
2386        .lookup         = proc_attr_dir_lookup,
2387        .getattr        = pid_getattr,
2388        .setattr        = proc_setattr,
2389};
2390
2391#endif
2392
2393#ifdef CONFIG_ELF_CORE
2394static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2395                                         size_t count, loff_t *ppos)
2396{
2397        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2398        struct mm_struct *mm;
2399        char buffer[PROC_NUMBUF];
2400        size_t len;
2401        int ret;
2402
2403        if (!task)
2404                return -ESRCH;
2405
2406        ret = 0;
2407        mm = get_task_mm(task);
2408        if (mm) {
2409                len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2410                               ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2411                                MMF_DUMP_FILTER_SHIFT));
2412                mmput(mm);
2413                ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2414        }
2415
2416        put_task_struct(task);
2417
2418        return ret;
2419}
2420
2421static ssize_t proc_coredump_filter_write(struct file *file,
2422                                          const char __user *buf,
2423                                          size_t count,
2424                                          loff_t *ppos)
2425{
2426        struct task_struct *task;
2427        struct mm_struct *mm;
2428        char buffer[PROC_NUMBUF], *end;
2429        unsigned int val;
2430        int ret;
2431        int i;
2432        unsigned long mask;
2433
2434        ret = -EFAULT;
2435        memset(buffer, 0, sizeof(buffer));
2436        if (count > sizeof(buffer) - 1)
2437                count = sizeof(buffer) - 1;
2438        if (copy_from_user(buffer, buf, count))
2439                goto out_no_task;
2440
2441        ret = -EINVAL;
2442        val = (unsigned int)simple_strtoul(buffer, &end, 0);
2443        if (*end == '\n')
2444                end++;
2445        if (end - buffer == 0)
2446                goto out_no_task;
2447
2448        ret = -ESRCH;
2449        task = get_proc_task(file->f_dentry->d_inode);
2450        if (!task)
2451                goto out_no_task;
2452
2453        ret = end - buffer;
2454        mm = get_task_mm(task);
2455        if (!mm)
2456                goto out_no_mm;
2457
2458        for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2459                if (val & mask)
2460                        set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2461                else
2462                        clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2463        }
2464
2465        mmput(mm);
2466 out_no_mm:
2467        put_task_struct(task);
2468 out_no_task:
2469        return ret;
2470}
2471
2472static const struct file_operations proc_coredump_filter_operations = {
2473        .read           = proc_coredump_filter_read,
2474        .write          = proc_coredump_filter_write,
2475        .llseek         = generic_file_llseek,
2476};
2477#endif
2478
2479/*
2480 * /proc/self:
2481 */
2482static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2483                              int buflen)
2484{
2485        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2486        pid_t tgid = task_tgid_nr_ns(current, ns);
2487        char tmp[PROC_NUMBUF];
2488        if (!tgid)
2489                return -ENOENT;
2490        sprintf(tmp, "%d", tgid);
2491        return vfs_readlink(dentry,buffer,buflen,tmp);
2492}
2493
2494static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2495{
2496        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2497        pid_t tgid = task_tgid_nr_ns(current, ns);
2498        char *name = ERR_PTR(-ENOENT);
2499        if (tgid) {
2500                name = __getname();
2501                if (!name)
2502                        name = ERR_PTR(-ENOMEM);
2503                else
2504                        sprintf(name, "%d", tgid);
2505        }
2506        nd_set_link(nd, name);
2507        return NULL;
2508}
2509
2510static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
2511                                void *cookie)
2512{
2513        char *s = nd_get_link(nd);
2514        if (!IS_ERR(s))
2515                __putname(s);
2516}
2517
2518static const struct inode_operations proc_self_inode_operations = {
2519        .readlink       = proc_self_readlink,
2520        .follow_link    = proc_self_follow_link,
2521        .put_link       = proc_self_put_link,
2522};
2523
2524/*
2525 * proc base
2526 *
2527 * These are the directory entries in the root directory of /proc
2528 * that properly belong to the /proc filesystem, as they describe
2529 * describe something that is process related.
2530 */
2531static const struct pid_entry proc_base_stuff[] = {
2532        NOD("self", S_IFLNK|S_IRWXUGO,
2533                &proc_self_inode_operations, NULL, {}),
2534};
2535
2536static struct dentry *proc_base_instantiate(struct inode *dir,
2537        struct dentry *dentry, struct task_struct *task, const void *ptr)
2538{
2539        const struct pid_entry *p = ptr;
2540        struct inode *inode;
2541        struct proc_inode *ei;
2542        struct dentry *error;
2543
2544        /* Allocate the inode */
2545        error = ERR_PTR(-ENOMEM);
2546        inode = new_inode(dir->i_sb);
2547        if (!inode)
2548                goto out;
2549
2550        /* Initialize the inode */
2551        ei = PROC_I(inode);
2552        inode->i_ino = get_next_ino();
2553        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2554
2555        /*
2556         * grab the reference to the task.
2557         */
2558        ei->pid = get_task_pid(task, PIDTYPE_PID);
2559        if (!ei->pid)
2560                goto out_iput;
2561
2562        inode->i_mode = p->mode;
2563        if (S_ISDIR(inode->i_mode))
2564                set_nlink(inode, 2);
2565        if (S_ISLNK(inode->i_mode))
2566                inode->i_size = 64;
2567        if (p->iop)
2568                inode->i_op = p->iop;
2569        if (p->fop)
2570                inode->i_fop = p->fop;
2571        ei->op = p->op;
2572        d_add(dentry, inode);
2573        error = NULL;
2574out:
2575        return error;
2576out_iput:
2577        iput(inode);
2578        goto out;
2579}
2580
2581static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2582{
2583        struct dentry *error;
2584        struct task_struct *task = get_proc_task(dir);
2585        const struct pid_entry *p, *last;
2586
2587        error = ERR_PTR(-ENOENT);
2588
2589        if (!task)
2590                goto out_no_task;
2591
2592        /* Lookup the directory entry */
2593        last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2594        for (p = proc_base_stuff; p <= last; p++) {
2595                if (p->len != dentry->d_name.len)
2596                        continue;
2597                if (!memcmp(dentry->d_name.name, p->name, p->len))
2598                        break;
2599        }
2600        if (p > last)
2601                goto out;
2602
2603        error = proc_base_instantiate(dir, dentry, task, p);
2604
2605out:
2606        put_task_struct(task);
2607out_no_task:
2608        return error;
2609}
2610
2611static int proc_base_fill_cache(struct file *filp, void *dirent,
2612        filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2613{
2614        return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2615                                proc_base_instantiate, task, p);
2616}
2617
2618#ifdef CONFIG_TASK_IO_ACCOUNTING
2619static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2620{
2621        struct task_io_accounting acct = task->ioac;
2622        unsigned long flags;
2623        int result;
2624
2625        result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2626        if (result)
2627                return result;
2628
2629        if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
2630                result = -EACCES;
2631                goto out_unlock;
2632        }
2633
2634        if (whole && lock_task_sighand(task, &flags)) {
2635                struct task_struct *t = task;
2636
2637                task_io_accounting_add(&acct, &task->signal->ioac);
2638                while_each_thread(task, t)
2639                        task_io_accounting_add(&acct, &t->ioac);
2640
2641                unlock_task_sighand(task, &flags);
2642        }
2643        result = sprintf(buffer,
2644                        "rchar: %llu\n"
2645                        "wchar: %llu\n"
2646                        "syscr: %llu\n"
2647                        "syscw: %llu\n"
2648                        "read_bytes: %llu\n"
2649                        "write_bytes: %llu\n"
2650                        "cancelled_write_bytes: %llu\n",
2651                        (unsigned long long)acct.rchar,
2652                        (unsigned long long)acct.wchar,
2653                        (unsigned long long)acct.syscr,
2654                        (unsigned long long)acct.syscw,
2655                        (unsigned long long)acct.read_bytes,
2656                        (unsigned long long)acct.write_bytes,
2657                        (unsigned long long)acct.cancelled_write_bytes);
2658out_unlock:
2659        mutex_unlock(&task->signal->cred_guard_mutex);
2660        return result;
2661}
2662
2663static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2664{
2665        return do_io_accounting(task, buffer, 0);
2666}
2667
2668static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2669{
2670        return do_io_accounting(task, buffer, 1);
2671}
2672#endif /* CONFIG_TASK_IO_ACCOUNTING */
2673
2674static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2675                                struct pid *pid, struct task_struct *task)
2676{
2677        int err = lock_trace(task);
2678        if (!err) {
2679                seq_printf(m, "%08x\n", task->personality);
2680                unlock_trace(task);
2681        }
2682        return err;
2683}
2684
2685/*
2686 * Thread groups
2687 */
2688static const struct file_operations proc_task_operations;
2689static const struct inode_operations proc_task_inode_operations;
2690
2691static const struct pid_entry tgid_base_stuff[] = {
2692        DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2693        DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2694        DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2695        DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2696#ifdef CONFIG_NET
2697        DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2698#endif
2699        REG("environ",    S_IRUSR, proc_environ_operations),
2700        INF("auxv",       S_IRUSR, proc_pid_auxv),
2701        ONE("status",     S_IRUGO, proc_pid_status),
2702        ONE("personality", S_IRUGO, proc_pid_personality),
2703        INF("limits",     S_IRUGO, proc_pid_limits),
2704#ifdef CONFIG_SCHED_DEBUG
2705        REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2706#endif
2707#ifdef CONFIG_SCHED_AUTOGROUP
2708        REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2709#endif
2710        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2711#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2712        INF("syscall",    S_IRUGO, proc_pid_syscall),
2713#endif
2714        INF("cmdline",    S_IRUGO, proc_pid_cmdline),
2715        ONE("stat",       S_IRUGO, proc_tgid_stat),
2716        ONE("statm",      S_IRUGO, proc_pid_statm),
2717        REG("maps",       S_IRUGO, proc_maps_operations),
2718#ifdef CONFIG_NUMA
2719        REG("numa_maps",  S_IRUGO, proc_numa_maps_operations),
2720#endif
2721        REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2722        LNK("cwd",        proc_cwd_link),
2723        LNK("root",       proc_root_link),
2724        LNK("exe",        proc_exe_link),
2725        REG("mounts",     S_IRUGO, proc_mounts_operations),
2726        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2727        REG("mountstats", S_IRUSR, proc_mountstats_operations),
2728#ifdef CONFIG_PROC_PAGE_MONITOR
2729        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2730        REG("smaps",      S_IRUGO, proc_smaps_operations),
2731        REG("pagemap",    S_IRUGO, proc_pagemap_operations),
2732#endif
2733#ifdef CONFIG_SECURITY
2734        DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2735#endif
2736#ifdef CONFIG_KALLSYMS
2737        INF("wchan",      S_IRUGO, proc_pid_wchan),
2738#endif
2739#ifdef CONFIG_STACKTRACE
2740        ONE("stack",      S_IRUGO, proc_pid_stack),
2741#endif
2742#ifdef CONFIG_SCHEDSTATS
2743        INF("schedstat",  S_IRUGO, proc_pid_schedstat),
2744#endif
2745#ifdef CONFIG_LATENCYTOP
2746        REG("latency",  S_IRUGO, proc_lstats_operations),
2747#endif
2748#ifdef CONFIG_PROC_PID_CPUSET
2749        REG("cpuset",     S_IRUGO, proc_cpuset_operations),
2750#endif
2751#ifdef CONFIG_CGROUPS
2752        REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2753#endif
2754        INF("oom_score",  S_IRUGO, proc_oom_score),
2755        REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
2756        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2757#ifdef CONFIG_AUDITSYSCALL
2758        REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2759        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2760#endif
2761#ifdef CONFIG_FAULT_INJECTION
2762        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2763#endif
2764#ifdef CONFIG_ELF_CORE
2765        REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2766#endif
2767#ifdef CONFIG_TASK_IO_ACCOUNTING
2768        INF("io",       S_IRUSR, proc_tgid_io_accounting),
2769#endif
2770#ifdef CONFIG_HARDWALL
2771        INF("hardwall",   S_IRUGO, proc_pid_hardwall),
2772#endif
2773};
2774
2775static int proc_tgid_base_readdir(struct file * filp,
2776                             void * dirent, filldir_t filldir)
2777{
2778        return proc_pident_readdir(filp,dirent,filldir,
2779                                   tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2780}
2781
2782static const struct file_operations proc_tgid_base_operations = {
2783        .read           = generic_read_dir,
2784        .readdir        = proc_tgid_base_readdir,
2785        .llseek         = default_llseek,
2786};
2787
2788static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2789        return proc_pident_lookup(dir, dentry,
2790                                  tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2791}
2792
2793static const struct inode_operations proc_tgid_base_inode_operations = {
2794        .lookup         = proc_tgid_base_lookup,
2795        .getattr        = pid_getattr,
2796        .setattr        = proc_setattr,
2797};
2798
2799static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2800{
2801        struct dentry *dentry, *leader, *dir;
2802        char buf[PROC_NUMBUF];
2803        struct qstr name;
2804
2805        name.name = buf;
2806        name.len = snprintf(buf, sizeof(buf), "%d", pid);
2807        dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2808        if (dentry) {
2809                shrink_dcache_parent(dentry);
2810                d_drop(dentry);
2811                dput(dentry);
2812        }
2813
2814        name.name = buf;
2815        name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2816        leader = d_hash_and_lookup(mnt->mnt_root, &name);
2817        if (!leader)
2818                goto out;
2819
2820        name.name = "task";
2821        name.len = strlen(name.name);
2822        dir = d_hash_and_lookup(leader, &name);
2823        if (!dir)
2824                goto out_put_leader;
2825
2826        name.name = buf;
2827        name.len = snprintf(buf, sizeof(buf), "%d", pid);
2828        dentry = d_hash_and_lookup(dir, &name);
2829        if (dentry) {
2830                shrink_dcache_parent(dentry);
2831                d_drop(dentry);
2832                dput(dentry);
2833        }
2834
2835        dput(dir);
2836out_put_leader:
2837        dput(leader);
2838out:
2839        return;
2840}
2841
2842/**
2843 * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2844 * @task: task that should be flushed.
2845 *
2846 * When flushing dentries from proc, one needs to flush them from global
2847 * proc (proc_mnt) and from all the namespaces' procs this task was seen
2848 * in. This call is supposed to do all of this job.
2849 *
2850 * Looks in the dcache for
2851 * /proc/@pid
2852 * /proc/@tgid/task/@pid
2853 * if either directory is present flushes it and all of it'ts children
2854 * from the dcache.
2855 *
2856 * It is safe and reasonable to cache /proc entries for a task until
2857 * that task exits.  After that they just clog up the dcache with
2858 * useless entries, possibly causing useful dcache entries to be
2859 * flushed instead.  This routine is proved to flush those useless
2860 * dcache entries at process exit time.
2861 *
2862 * NOTE: This routine is just an optimization so it does not guarantee
2863 *       that no dcache entries will exist at process exit time it
2864 *       just makes it very unlikely that any will persist.
2865 */
2866
2867void proc_flush_task(struct task_struct *task)
2868{
2869        int i;
2870        struct pid *pid, *tgid;
2871        struct upid *upid;
2872
2873        pid = task_pid(task);
2874        tgid = task_tgid(task);
2875
2876        for (i = 0; i <= pid->level; i++) {
2877                upid = &pid->numbers[i];
2878                proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2879                                        tgid->numbers[i].nr);
2880        }
2881
2882        upid = &pid->numbers[pid->level];
2883        if (upid->nr == 1)
2884                pid_ns_release_proc(upid->ns);
2885}
2886
2887static struct dentry *proc_pid_instantiate(struct inode *dir,
2888                                           struct dentry * dentry,
2889                                           struct task_struct *task, const void *ptr)
2890{
2891        struct dentry *error = ERR_PTR(-ENOENT);
2892        struct inode *inode;
2893
2894        inode = proc_pid_make_inode(dir->i_sb, task);
2895        if (!inode)
2896                goto out;
2897
2898        inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2899        inode->i_op = &proc_tgid_base_inode_operations;
2900        inode->i_fop = &proc_tgid_base_operations;
2901        inode->i_flags|=S_IMMUTABLE;
2902
2903        set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
2904                                                  ARRAY_SIZE(tgid_base_stuff)));
2905
2906        d_set_d_op(dentry, &pid_dentry_operations);
2907
2908        d_add(dentry, inode);
2909        /* Close the race of the process dying before we return the dentry */
2910        if (pid_revalidate(dentry, NULL))
2911                error = NULL;
2912out:
2913        return error;
2914}
2915
2916struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2917{
2918        struct dentry *result;
2919        struct task_struct *task;
2920        unsigned tgid;
2921        struct pid_namespace *ns;
2922
2923        result = proc_base_lookup(dir, dentry);
2924        if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
2925                goto out;
2926
2927        tgid = name_to_int(dentry);
2928        if (tgid == ~0U)
2929                goto out;
2930
2931        ns = dentry->d_sb->s_fs_info;
2932        rcu_read_lock();
2933        task = find_task_by_pid_ns(tgid, ns);
2934        if (task)
2935                get_task_struct(task);
2936        rcu_read_unlock();
2937        if (!task)
2938                goto out;
2939
2940        result = proc_pid_instantiate(dir, dentry, task, NULL);
2941        put_task_struct(task);
2942out:
2943        return result;
2944}
2945
2946/*
2947 * Find the first task with tgid >= tgid
2948 *
2949 */
2950struct tgid_iter {
2951        unsigned int tgid;
2952        struct task_struct *task;
2953};
2954static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
2955{
2956        struct pid *pid;
2957
2958        if (iter.task)
2959                put_task_struct(iter.task);
2960        rcu_read_lock();
2961retry:
2962        iter.task = NULL;
2963        pid = find_ge_pid(iter.tgid, ns);
2964        if (pid) {
2965                iter.tgid = pid_nr_ns(pid, ns);
2966                iter.task = pid_task(pid, PIDTYPE_PID);
2967                /* What we to know is if the pid we have find is the
2968                 * pid of a thread_group_leader.  Testing for task
2969                 * being a thread_group_leader is the obvious thing
2970                 * todo but there is a window when it fails, due to
2971                 * the pid transfer logic in de_thread.
2972                 *
2973                 * So we perform the straight forward test of seeing
2974                 * if the pid we have found is the pid of a thread
2975                 * group leader, and don't worry if the task we have
2976                 * found doesn't happen to be a thread group leader.
2977                 * As we don't care in the case of readdir.
2978                 */
2979                if (!iter.task || !has_group_leader_pid(iter.task)) {
2980                        iter.tgid += 1;
2981                        goto retry;
2982                }
2983                get_task_struct(iter.task);
2984        }
2985        rcu_read_unlock();
2986        return iter;
2987}
2988
2989#define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
2990
2991static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
2992        struct tgid_iter iter)
2993{
2994        char name[PROC_NUMBUF];
2995        int len = snprintf(name, sizeof(name), "%d", iter.tgid);
2996        return proc_fill_cache(filp, dirent, filldir, name, len,
2997                                proc_pid_instantiate, iter.task, NULL);
2998}
2999
3000/* for the /proc/ directory itself, after non-process stuff has been done */
3001int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
3002{
3003        unsigned int nr;
3004        struct task_struct *reaper;
3005        struct tgid_iter iter;
3006        struct pid_namespace *ns;
3007
3008        if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
3009                goto out_no_task;
3010        nr = filp->f_pos - FIRST_PROCESS_ENTRY;
3011
3012        reaper = get_proc_task(filp->f_path.dentry->d_inode);
3013        if (!reaper)
3014                goto out_no_task;
3015
3016        for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
3017                const struct pid_entry *p = &proc_base_stuff[nr];
3018                if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
3019                        goto out;
3020        }
3021
3022        ns = filp->f_dentry->d_sb->s_fs_info;
3023        iter.task = NULL;
3024        iter.tgid = filp->f_pos - TGID_OFFSET;
3025        for (iter = next_tgid(ns, iter);
3026             iter.task;
3027             iter.tgid += 1, iter = next_tgid(ns, iter)) {
3028                filp->f_pos = iter.tgid + TGID_OFFSET;
3029                if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
3030                        put_task_struct(iter.task);
3031                        goto out;
3032                }
3033        }
3034        filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
3035out:
3036        put_task_struct(reaper);
3037out_no_task:
3038        return 0;
3039}
3040
3041/*
3042 * Tasks
3043 */
3044static const struct pid_entry tid_base_stuff[] = {
3045        DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3046        DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3047        DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3048        REG("environ",   S_IRUSR, proc_environ_operations),
3049        INF("auxv",      S_IRUSR, proc_pid_auxv),
3050        ONE("status",    S_IRUGO, proc_pid_status),
3051        ONE("personality", S_IRUGO, proc_pid_personality),
3052        INF("limits",    S_IRUGO, proc_pid_limits),
3053#ifdef CONFIG_SCHED_DEBUG
3054        REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3055#endif
3056        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3057#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3058        INF("syscall",   S_IRUGO, proc_pid_syscall),
3059#endif
3060        INF("cmdline",   S_IRUGO, proc_pid_cmdline),
3061        ONE("stat",      S_IRUGO, proc_tid_stat),
3062        ONE("statm",     S_IRUGO, proc_pid_statm),
3063        REG("maps",      S_IRUGO, proc_maps_operations),
3064#ifdef CONFIG_NUMA
3065        REG("numa_maps", S_IRUGO, proc_numa_maps_operations),
3066#endif
3067        REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3068        LNK("cwd",       proc_cwd_link),
3069        LNK("root",      proc_root_link),
3070        LNK("exe",       proc_exe_link),
3071        REG("mounts",    S_IRUGO, proc_mounts_operations),
3072        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3073#ifdef CONFIG_PROC_PAGE_MONITOR
3074        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3075        REG("smaps",     S_IRUGO, proc_smaps_operations),
3076        REG("pagemap",    S_IRUGO, proc_pagemap_operations),
3077#endif
3078#ifdef CONFIG_SECURITY
3079        DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3080#endif
3081#ifdef CONFIG_KALLSYMS
3082        INF("wchan",     S_IRUGO, proc_pid_wchan),
3083#endif
3084#ifdef CONFIG_STACKTRACE
3085        ONE("stack",      S_IRUGO, proc_pid_stack),
3086#endif
3087#ifdef CONFIG_SCHEDSTATS
3088        INF("schedstat", S_IRUGO, proc_pid_schedstat),
3089#endif
3090#ifdef CONFIG_LATENCYTOP
3091        REG("latency",  S_IRUGO, proc_lstats_operations),
3092#endif
3093#ifdef CONFIG_PROC_PID_CPUSET
3094        REG("cpuset",    S_IRUGO, proc_cpuset_operations),
3095#endif
3096#ifdef CONFIG_CGROUPS
3097        REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3098#endif
3099        INF("oom_score", S_IRUGO, proc_oom_score),
3100        REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
3101        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3102#ifdef CONFIG_AUDITSYSCALL
3103        REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3104        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3105#endif
3106#ifdef CONFIG_FAULT_INJECTION
3107        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3108#endif
3109#ifdef CONFIG_TASK_IO_ACCOUNTING
3110        INF("io",       S_IRUSR, proc_tid_io_accounting),
3111#endif
3112#ifdef CONFIG_HARDWALL
3113        INF("hardwall",   S_IRUGO, proc_pid_hardwall),
3114#endif
3115};
3116
3117static int proc_tid_base_readdir(struct file * filp,
3118                             void * dirent, filldir_t filldir)
3119{
3120        return proc_pident_readdir(filp,dirent,filldir,
3121                                   tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
3122}
3123
3124static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
3125        return proc_pident_lookup(dir, dentry,
3126                                  tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3127}
3128
3129static const struct file_operations proc_tid_base_operations = {
3130        .read           = generic_read_dir,
3131        .readdir        = proc_tid_base_readdir,
3132        .llseek         = default_llseek,
3133};
3134
3135static const struct inode_operations proc_tid_base_inode_operations = {
3136        .lookup         = proc_tid_base_lookup,
3137        .getattr        = pid_getattr,
3138        .setattr        = proc_setattr,
3139};
3140
3141static struct dentry *proc_task_instantiate(struct inode *dir,
3142        struct dentry *dentry, struct task_struct *task, const void *ptr)
3143{
3144        struct dentry *error = ERR_PTR(-ENOENT);
3145        struct inode *inode;
3146        inode = proc_pid_make_inode(dir->i_sb, task);
3147
3148        if (!inode)
3149                goto out;
3150        inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3151        inode->i_op = &proc_tid_base_inode_operations;
3152        inode->i_fop = &proc_tid_base_operations;
3153        inode->i_flags|=S_IMMUTABLE;
3154
3155        set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
3156                                                  ARRAY_SIZE(tid_base_stuff)));
3157
3158        d_set_d_op(dentry, &pid_dentry_operations);
3159
3160        d_add(dentry, inode);
3161        /* Close the race of the process dying before we return the dentry */
3162        if (pid_revalidate(dentry, NULL))
3163                error = NULL;
3164out:
3165        return error;
3166}
3167
3168static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3169{
3170        struct dentry *result = ERR_PTR(-ENOENT);
3171        struct task_struct *task;
3172        struct task_struct *leader = get_proc_task(dir);
3173        unsigned tid;
3174        struct pid_namespace *ns;
3175
3176        if (!leader)
3177                goto out_no_task;
3178
3179        tid = name_to_int(dentry);
3180        if (tid == ~0U)
3181                goto out;
3182
3183        ns = dentry->d_sb->s_fs_info;
3184        rcu_read_lock();
3185        task = find_task_by_pid_ns(tid, ns);
3186        if (task)
3187                get_task_struct(task);
3188        rcu_read_unlock();
3189        if (!task)
3190                goto out;
3191        if (!same_thread_group(leader, task))
3192                goto out_drop_task;
3193
3194        result = proc_task_instantiate(dir, dentry, task, NULL);
3195out_drop_task:
3196        put_task_struct(task);
3197out:
3198        put_task_struct(leader);
3199out_no_task:
3200        return result;
3201}
3202
3203/*
3204 * Find the first tid of a thread group to return to user space.
3205 *
3206 * Usually this is just the thread group leader, but if the users
3207 * buffer was too small or there was a seek into the middle of the
3208 * directory we have more work todo.
3209 *
3210 * In the case of a short read we start with find_task_by_pid.
3211 *
3212 * In the case of a seek we start with the leader and walk nr
3213 * threads past it.
3214 */
3215static struct task_struct *first_tid(struct task_struct *leader,
3216                int tid, int nr, struct pid_namespace *ns)
3217{
3218        struct task_struct *pos;
3219
3220        rcu_read_lock();
3221        /* Attempt to start with the pid of a thread */
3222        if (tid && (nr > 0)) {
3223                pos = find_task_by_pid_ns(tid, ns);
3224                if (pos && (pos->group_leader == leader))
3225                        goto found;
3226        }
3227
3228        /* If nr exceeds the number of threads there is nothing todo */
3229        pos = NULL;
3230        if (nr && nr >= get_nr_threads(leader))
3231                goto out;
3232
3233        /* If we haven't found our starting place yet start
3234         * with the leader and walk nr threads forward.
3235         */
3236        for (pos = leader; nr > 0; --nr) {
3237                pos = next_thread(pos);
3238                if (pos == leader) {
3239                        pos = NULL;
3240                        goto out;
3241                }
3242        }
3243found:
3244        get_task_struct(pos);
3245out:
3246        rcu_read_unlock();
3247        return pos;
3248}
3249
3250/*
3251 * Find the next thread in the thread list.
3252 * Return NULL if there is an error or no next thread.
3253 *
3254 * The reference to the input task_struct is released.
3255 */
3256static struct task_struct *next_tid(struct task_struct *start)
3257{
3258        struct task_struct *pos = NULL;
3259        rcu_read_lock();
3260        if (pid_alive(start)) {
3261                pos = next_thread(start);
3262                if (thread_group_leader(pos))
3263                        pos = NULL;
3264                else
3265                        get_task_struct(pos);
3266        }
3267        rcu_read_unlock();
3268        put_task_struct(start);
3269        return pos;
3270}
3271
3272static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3273        struct task_struct *task, int tid)
3274{
3275        char name[PROC_NUMBUF];
3276        int len = snprintf(name, sizeof(name), "%d", tid);
3277        return proc_fill_cache(filp, dirent, filldir, name, len,
3278                                proc_task_instantiate, task, NULL);
3279}
3280
3281/* for the /proc/TGID/task/ directories */
3282static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3283{
3284        struct dentry *dentry = filp->f_path.dentry;
3285        struct inode *inode = dentry->d_inode;
3286        struct task_struct *leader = NULL;
3287        struct task_struct *task;
3288        int retval = -ENOENT;
3289        ino_t ino;
3290        int tid;
3291        struct pid_namespace *ns;
3292
3293        task = get_proc_task(inode);
3294        if (!task)
3295                goto out_no_task;
3296        rcu_read_lock();
3297        if (pid_alive(task)) {
3298                leader = task->group_leader;
3299                get_task_struct(leader);
3300        }
3301        rcu_read_unlock();
3302        put_task_struct(task);
3303        if (!leader)
3304                goto out_no_task;
3305        retval = 0;
3306
3307        switch ((unsigned long)filp->f_pos) {
3308        case 0:
3309                ino = inode->i_ino;
3310                if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) < 0)
3311                        goto out;
3312                filp->f_pos++;
3313                /* fall through */
3314        case 1:
3315                ino = parent_ino(dentry);
3316                if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) < 0)
3317                        goto out;
3318                filp->f_pos++;
3319                /* fall through */
3320        }
3321
3322        /* f_version caches the tgid value that the last readdir call couldn't
3323         * return. lseek aka telldir automagically resets f_version to 0.
3324         */
3325        ns = filp->f_dentry->d_sb->s_fs_info;
3326        tid = (int)filp->f_version;
3327        filp->f_version = 0;
3328        for (task = first_tid(leader, tid, filp->f_pos - 2, ns);
3329             task;
3330             task = next_tid(task), filp->f_pos++) {
3331                tid = task_pid_nr_ns(task, ns);
3332                if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3333                        /* returning this tgid failed, save it as the first
3334                         * pid for the next readir call */
3335                        filp->f_version = (u64)tid;
3336                        put_task_struct(task);
3337                        break;
3338                }
3339        }
3340out:
3341        put_task_struct(leader);
3342out_no_task:
3343        return retval;
3344}
3345
3346static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3347{
3348        struct inode *inode = dentry->d_inode;
3349        struct task_struct *p = get_proc_task(inode);
3350        generic_fillattr(inode, stat);
3351
3352        if (p) {
3353                stat->nlink += get_nr_threads(p);
3354                put_task_struct(p);
3355        }
3356
3357        return 0;
3358}
3359
3360static const struct inode_operations proc_task_inode_operations = {
3361        .lookup         = proc_task_lookup,
3362        .getattr        = proc_task_getattr,
3363        .setattr        = proc_setattr,
3364};
3365
3366static const struct file_operations proc_task_operations = {
3367        .read           = generic_read_dir,
3368        .readdir        = proc_task_readdir,
3369        .llseek         = default_llseek,
3370};
3371
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.