linux/fs/proc/base.c
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   1/*
   2 *  linux/fs/proc/base.c
   3 *
   4 *  Copyright (C) 1991, 1992 Linus Torvalds
   5 *
   6 *  proc base directory handling functions
   7 *
   8 *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
   9 *  Instead of using magical inumbers to determine the kind of object
  10 *  we allocate and fill in-core inodes upon lookup. They don't even
  11 *  go into icache. We cache the reference to task_struct upon lookup too.
  12 *  Eventually it should become a filesystem in its own. We don't use the
  13 *  rest of procfs anymore.
  14 *
  15 *
  16 *  Changelog:
  17 *  17-Jan-2005
  18 *  Allan Bezerra
  19 *  Bruna Moreira <bruna.moreira@indt.org.br>
  20 *  Edjard Mota <edjard.mota@indt.org.br>
  21 *  Ilias Biris <ilias.biris@indt.org.br>
  22 *  Mauricio Lin <mauricio.lin@indt.org.br>
  23 *
  24 *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  25 *
  26 *  A new process specific entry (smaps) included in /proc. It shows the
  27 *  size of rss for each memory area. The maps entry lacks information
  28 *  about physical memory size (rss) for each mapped file, i.e.,
  29 *  rss information for executables and library files.
  30 *  This additional information is useful for any tools that need to know
  31 *  about physical memory consumption for a process specific library.
  32 *
  33 *  Changelog:
  34 *  21-Feb-2005
  35 *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  36 *  Pud inclusion in the page table walking.
  37 *
  38 *  ChangeLog:
  39 *  10-Mar-2005
  40 *  10LE Instituto Nokia de Tecnologia - INdT:
  41 *  A better way to walks through the page table as suggested by Hugh Dickins.
  42 *
  43 *  Simo Piiroinen <simo.piiroinen@nokia.com>:
  44 *  Smaps information related to shared, private, clean and dirty pages.
  45 *
  46 *  Paul Mundt <paul.mundt@nokia.com>:
  47 *  Overall revision about smaps.
  48 */
  49
  50#include <asm/uaccess.h>
  51
  52#include <linux/errno.h>
  53#include <linux/time.h>
  54#include <linux/proc_fs.h>
  55#include <linux/stat.h>
  56#include <linux/task_io_accounting_ops.h>
  57#include <linux/init.h>
  58#include <linux/capability.h>
  59#include <linux/file.h>
  60#include <linux/fdtable.h>
  61#include <linux/string.h>
  62#include <linux/seq_file.h>
  63#include <linux/namei.h>
  64#include <linux/mnt_namespace.h>
  65#include <linux/mm.h>
  66#include <linux/swap.h>
  67#include <linux/rcupdate.h>
  68#include <linux/kallsyms.h>
  69#include <linux/stacktrace.h>
  70#include <linux/resource.h>
  71#include <linux/module.h>
  72#include <linux/mount.h>
  73#include <linux/security.h>
  74#include <linux/ptrace.h>
  75#include <linux/tracehook.h>
  76#include <linux/cgroup.h>
  77#include <linux/cpuset.h>
  78#include <linux/audit.h>
  79#include <linux/poll.h>
  80#include <linux/nsproxy.h>
  81#include <linux/oom.h>
  82#include <linux/elf.h>
  83#include <linux/pid_namespace.h>
  84#include <linux/fs_struct.h>
  85#include <linux/slab.h>
  86#include "internal.h"
  87
  88/* NOTE:
  89 *      Implementing inode permission operations in /proc is almost
  90 *      certainly an error.  Permission checks need to happen during
  91 *      each system call not at open time.  The reason is that most of
  92 *      what we wish to check for permissions in /proc varies at runtime.
  93 *
  94 *      The classic example of a problem is opening file descriptors
  95 *      in /proc for a task before it execs a suid executable.
  96 */
  97
  98struct pid_entry {
  99        char *name;
 100        int len;
 101        mode_t mode;
 102        const struct inode_operations *iop;
 103        const struct file_operations *fop;
 104        union proc_op op;
 105};
 106
 107#define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 108        .name = (NAME),                                 \
 109        .len  = sizeof(NAME) - 1,                       \
 110        .mode = MODE,                                   \
 111        .iop  = IOP,                                    \
 112        .fop  = FOP,                                    \
 113        .op   = OP,                                     \
 114}
 115
 116#define DIR(NAME, MODE, iops, fops)     \
 117        NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 118#define LNK(NAME, get_link)                                     \
 119        NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 120                &proc_pid_link_inode_operations, NULL,          \
 121                { .proc_get_link = get_link } )
 122#define REG(NAME, MODE, fops)                           \
 123        NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 124#define INF(NAME, MODE, read)                           \
 125        NOD(NAME, (S_IFREG|(MODE)),                     \
 126                NULL, &proc_info_file_operations,       \
 127                { .proc_read = read } )
 128#define ONE(NAME, MODE, show)                           \
 129        NOD(NAME, (S_IFREG|(MODE)),                     \
 130                NULL, &proc_single_file_operations,     \
 131                { .proc_show = show } )
 132
 133/*
 134 * Count the number of hardlinks for the pid_entry table, excluding the .
 135 * and .. links.
 136 */
 137static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
 138        unsigned int n)
 139{
 140        unsigned int i;
 141        unsigned int count;
 142
 143        count = 0;
 144        for (i = 0; i < n; ++i) {
 145                if (S_ISDIR(entries[i].mode))
 146                        ++count;
 147        }
 148
 149        return count;
 150}
 151
 152static int get_task_root(struct task_struct *task, struct path *root)
 153{
 154        int result = -ENOENT;
 155
 156        task_lock(task);
 157        if (task->fs) {
 158                get_fs_root(task->fs, root);
 159                result = 0;
 160        }
 161        task_unlock(task);
 162        return result;
 163}
 164
 165static int proc_cwd_link(struct inode *inode, struct path *path)
 166{
 167        struct task_struct *task = get_proc_task(inode);
 168        int result = -ENOENT;
 169
 170        if (task) {
 171                task_lock(task);
 172                if (task->fs) {
 173                        get_fs_pwd(task->fs, path);
 174                        result = 0;
 175                }
 176                task_unlock(task);
 177                put_task_struct(task);
 178        }
 179        return result;
 180}
 181
 182static int proc_root_link(struct inode *inode, struct path *path)
 183{
 184        struct task_struct *task = get_proc_task(inode);
 185        int result = -ENOENT;
 186
 187        if (task) {
 188                result = get_task_root(task, path);
 189                put_task_struct(task);
 190        }
 191        return result;
 192}
 193
 194static struct mm_struct *__check_mem_permission(struct task_struct *task)
 195{
 196        struct mm_struct *mm;
 197
 198        mm = get_task_mm(task);
 199        if (!mm)
 200                return ERR_PTR(-EINVAL);
 201
 202        /*
 203         * A task can always look at itself, in case it chooses
 204         * to use system calls instead of load instructions.
 205         */
 206        if (task == current)
 207                return mm;
 208
 209        /*
 210         * If current is actively ptrace'ing, and would also be
 211         * permitted to freshly attach with ptrace now, permit it.
 212         */
 213        if (task_is_stopped_or_traced(task)) {
 214                int match;
 215                rcu_read_lock();
 216                match = (tracehook_tracer_task(task) == current);
 217                rcu_read_unlock();
 218                if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
 219                        return mm;
 220        }
 221
 222        /*
 223         * No one else is allowed.
 224         */
 225        mmput(mm);
 226        return ERR_PTR(-EPERM);
 227}
 228
 229/*
 230 * If current may access user memory in @task return a reference to the
 231 * corresponding mm, otherwise ERR_PTR.
 232 */
 233static struct mm_struct *check_mem_permission(struct task_struct *task)
 234{
 235        struct mm_struct *mm;
 236        int err;
 237
 238        /*
 239         * Avoid racing if task exec's as we might get a new mm but validate
 240         * against old credentials.
 241         */
 242        err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 243        if (err)
 244                return ERR_PTR(err);
 245
 246        mm = __check_mem_permission(task);
 247        mutex_unlock(&task->signal->cred_guard_mutex);
 248
 249        return mm;
 250}
 251
 252struct mm_struct *mm_for_maps(struct task_struct *task)
 253{
 254        struct mm_struct *mm;
 255        int err;
 256
 257        err =  mutex_lock_killable(&task->signal->cred_guard_mutex);
 258        if (err)
 259                return ERR_PTR(err);
 260
 261        mm = get_task_mm(task);
 262        if (mm && mm != current->mm &&
 263                        !ptrace_may_access(task, PTRACE_MODE_READ)) {
 264                mmput(mm);
 265                mm = ERR_PTR(-EACCES);
 266        }
 267        mutex_unlock(&task->signal->cred_guard_mutex);
 268
 269        return mm;
 270}
 271
 272static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 273{
 274        int res = 0;
 275        unsigned int len;
 276        struct mm_struct *mm = get_task_mm(task);
 277        if (!mm)
 278                goto out;
 279        if (!mm->arg_end)
 280                goto out_mm;    /* Shh! No looking before we're done */
 281
 282        len = mm->arg_end - mm->arg_start;
 283 
 284        if (len > PAGE_SIZE)
 285                len = PAGE_SIZE;
 286 
 287        res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 288
 289        // If the nul at the end of args has been overwritten, then
 290        // assume application is using setproctitle(3).
 291        if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 292                len = strnlen(buffer, res);
 293                if (len < res) {
 294                    res = len;
 295                } else {
 296                        len = mm->env_end - mm->env_start;
 297                        if (len > PAGE_SIZE - res)
 298                                len = PAGE_SIZE - res;
 299                        res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 300                        res = strnlen(buffer, res);
 301                }
 302        }
 303out_mm:
 304        mmput(mm);
 305out:
 306        return res;
 307}
 308
 309static int proc_pid_auxv(struct task_struct *task, char *buffer)
 310{
 311        struct mm_struct *mm = mm_for_maps(task);
 312        int res = PTR_ERR(mm);
 313        if (mm && !IS_ERR(mm)) {
 314                unsigned int nwords = 0;
 315                do {
 316                        nwords += 2;
 317                } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 318                res = nwords * sizeof(mm->saved_auxv[0]);
 319                if (res > PAGE_SIZE)
 320                        res = PAGE_SIZE;
 321                memcpy(buffer, mm->saved_auxv, res);
 322                mmput(mm);
 323        }
 324        return res;
 325}
 326
 327
 328#ifdef CONFIG_KALLSYMS
 329/*
 330 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 331 * Returns the resolved symbol.  If that fails, simply return the address.
 332 */
 333static int proc_pid_wchan(struct task_struct *task, char *buffer)
 334{
 335        unsigned long wchan;
 336        char symname[KSYM_NAME_LEN];
 337
 338        wchan = get_wchan(task);
 339
 340        if (lookup_symbol_name(wchan, symname) < 0)
 341                if (!ptrace_may_access(task, PTRACE_MODE_READ))
 342                        return 0;
 343                else
 344                        return sprintf(buffer, "%lu", wchan);
 345        else
 346                return sprintf(buffer, "%s", symname);
 347}
 348#endif /* CONFIG_KALLSYMS */
 349
 350static int lock_trace(struct task_struct *task)
 351{
 352        int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 353        if (err)
 354                return err;
 355        if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
 356                mutex_unlock(&task->signal->cred_guard_mutex);
 357                return -EPERM;
 358        }
 359        return 0;
 360}
 361
 362static void unlock_trace(struct task_struct *task)
 363{
 364        mutex_unlock(&task->signal->cred_guard_mutex);
 365}
 366
 367#ifdef CONFIG_STACKTRACE
 368
 369#define MAX_STACK_TRACE_DEPTH   64
 370
 371static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 372                          struct pid *pid, struct task_struct *task)
 373{
 374        struct stack_trace trace;
 375        unsigned long *entries;
 376        int err;
 377        int i;
 378
 379        entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 380        if (!entries)
 381                return -ENOMEM;
 382
 383        trace.nr_entries        = 0;
 384        trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 385        trace.entries           = entries;
 386        trace.skip              = 0;
 387
 388        err = lock_trace(task);
 389        if (!err) {
 390                save_stack_trace_tsk(task, &trace);
 391
 392                for (i = 0; i < trace.nr_entries; i++) {
 393                        seq_printf(m, "[<%pK>] %pS\n",
 394                                   (void *)entries[i], (void *)entries[i]);
 395                }
 396                unlock_trace(task);
 397        }
 398        kfree(entries);
 399
 400        return err;
 401}
 402#endif
 403
 404#ifdef CONFIG_SCHEDSTATS
 405/*
 406 * Provides /proc/PID/schedstat
 407 */
 408static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 409{
 410        return sprintf(buffer, "%llu %llu %lu\n",
 411                        (unsigned long long)task->se.sum_exec_runtime,
 412                        (unsigned long long)task->sched_info.run_delay,
 413                        task->sched_info.pcount);
 414}
 415#endif
 416
 417#ifdef CONFIG_LATENCYTOP
 418static int lstats_show_proc(struct seq_file *m, void *v)
 419{
 420        int i;
 421        struct inode *inode = m->private;
 422        struct task_struct *task = get_proc_task(inode);
 423
 424        if (!task)
 425                return -ESRCH;
 426        seq_puts(m, "Latency Top version : v0.1\n");
 427        for (i = 0; i < 32; i++) {
 428                struct latency_record *lr = &task->latency_record[i];
 429                if (lr->backtrace[0]) {
 430                        int q;
 431                        seq_printf(m, "%i %li %li",
 432                                   lr->count, lr->time, lr->max);
 433                        for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 434                                unsigned long bt = lr->backtrace[q];
 435                                if (!bt)
 436                                        break;
 437                                if (bt == ULONG_MAX)
 438                                        break;
 439                                seq_printf(m, " %ps", (void *)bt);
 440                        }
 441                        seq_putc(m, '\n');
 442                }
 443
 444        }
 445        put_task_struct(task);
 446        return 0;
 447}
 448
 449static int lstats_open(struct inode *inode, struct file *file)
 450{
 451        return single_open(file, lstats_show_proc, inode);
 452}
 453
 454static ssize_t lstats_write(struct file *file, const char __user *buf,
 455                            size_t count, loff_t *offs)
 456{
 457        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 458
 459        if (!task)
 460                return -ESRCH;
 461        clear_all_latency_tracing(task);
 462        put_task_struct(task);
 463
 464        return count;
 465}
 466
 467static const struct file_operations proc_lstats_operations = {
 468        .open           = lstats_open,
 469        .read           = seq_read,
 470        .write          = lstats_write,
 471        .llseek         = seq_lseek,
 472        .release        = single_release,
 473};
 474
 475#endif
 476
 477static int proc_oom_score(struct task_struct *task, char *buffer)
 478{
 479        unsigned long points = 0;
 480
 481        read_lock(&tasklist_lock);
 482        if (pid_alive(task))
 483                points = oom_badness(task, NULL, NULL,
 484                                        totalram_pages + total_swap_pages);
 485        read_unlock(&tasklist_lock);
 486        return sprintf(buffer, "%lu\n", points);
 487}
 488
 489struct limit_names {
 490        char *name;
 491        char *unit;
 492};
 493
 494static const struct limit_names lnames[RLIM_NLIMITS] = {
 495        [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 496        [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 497        [RLIMIT_DATA] = {"Max data size", "bytes"},
 498        [RLIMIT_STACK] = {"Max stack size", "bytes"},
 499        [RLIMIT_CORE] = {"Max core file size", "bytes"},
 500        [RLIMIT_RSS] = {"Max resident set", "bytes"},
 501        [RLIMIT_NPROC] = {"Max processes", "processes"},
 502        [RLIMIT_NOFILE] = {"Max open files", "files"},
 503        [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 504        [RLIMIT_AS] = {"Max address space", "bytes"},
 505        [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 506        [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 507        [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 508        [RLIMIT_NICE] = {"Max nice priority", NULL},
 509        [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 510        [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 511};
 512
 513/* Display limits for a process */
 514static int proc_pid_limits(struct task_struct *task, char *buffer)
 515{
 516        unsigned int i;
 517        int count = 0;
 518        unsigned long flags;
 519        char *bufptr = buffer;
 520
 521        struct rlimit rlim[RLIM_NLIMITS];
 522
 523        if (!lock_task_sighand(task, &flags))
 524                return 0;
 525        memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 526        unlock_task_sighand(task, &flags);
 527
 528        /*
 529         * print the file header
 530         */
 531        count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
 532                        "Limit", "Soft Limit", "Hard Limit", "Units");
 533
 534        for (i = 0; i < RLIM_NLIMITS; i++) {
 535                if (rlim[i].rlim_cur == RLIM_INFINITY)
 536                        count += sprintf(&bufptr[count], "%-25s %-20s ",
 537                                         lnames[i].name, "unlimited");
 538                else
 539                        count += sprintf(&bufptr[count], "%-25s %-20lu ",
 540                                         lnames[i].name, rlim[i].rlim_cur);
 541
 542                if (rlim[i].rlim_max == RLIM_INFINITY)
 543                        count += sprintf(&bufptr[count], "%-20s ", "unlimited");
 544                else
 545                        count += sprintf(&bufptr[count], "%-20lu ",
 546                                         rlim[i].rlim_max);
 547
 548                if (lnames[i].unit)
 549                        count += sprintf(&bufptr[count], "%-10s\n",
 550                                         lnames[i].unit);
 551                else
 552                        count += sprintf(&bufptr[count], "\n");
 553        }
 554
 555        return count;
 556}
 557
 558#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 559static int proc_pid_syscall(struct task_struct *task, char *buffer)
 560{
 561        long nr;
 562        unsigned long args[6], sp, pc;
 563        int res = lock_trace(task);
 564        if (res)
 565                return res;
 566
 567        if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 568                res = sprintf(buffer, "running\n");
 569        else if (nr < 0)
 570                res = sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 571        else
 572                res = sprintf(buffer,
 573                       "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 574                       nr,
 575                       args[0], args[1], args[2], args[3], args[4], args[5],
 576                       sp, pc);
 577        unlock_trace(task);
 578        return res;
 579}
 580#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 581
 582/************************************************************************/
 583/*                       Here the fs part begins                        */
 584/************************************************************************/
 585
 586/* permission checks */
 587static int proc_fd_access_allowed(struct inode *inode)
 588{
 589        struct task_struct *task;
 590        int allowed = 0;
 591        /* Allow access to a task's file descriptors if it is us or we
 592         * may use ptrace attach to the process and find out that
 593         * information.
 594         */
 595        task = get_proc_task(inode);
 596        if (task) {
 597                allowed = ptrace_may_access(task, PTRACE_MODE_READ);
 598                put_task_struct(task);
 599        }
 600        return allowed;
 601}
 602
 603static int proc_setattr(struct dentry *dentry, struct iattr *attr)
 604{
 605        int error;
 606        struct inode *inode = dentry->d_inode;
 607
 608        if (attr->ia_valid & ATTR_MODE)
 609                return -EPERM;
 610
 611        error = inode_change_ok(inode, attr);
 612        if (error)
 613                return error;
 614
 615        if ((attr->ia_valid & ATTR_SIZE) &&
 616            attr->ia_size != i_size_read(inode)) {
 617                error = vmtruncate(inode, attr->ia_size);
 618                if (error)
 619                        return error;
 620        }
 621
 622        setattr_copy(inode, attr);
 623        mark_inode_dirty(inode);
 624        return 0;
 625}
 626
 627static const struct inode_operations proc_def_inode_operations = {
 628        .setattr        = proc_setattr,
 629};
 630
 631static int mounts_open_common(struct inode *inode, struct file *file,
 632                              const struct seq_operations *op)
 633{
 634        struct task_struct *task = get_proc_task(inode);
 635        struct nsproxy *nsp;
 636        struct mnt_namespace *ns = NULL;
 637        struct path root;
 638        struct proc_mounts *p;
 639        int ret = -EINVAL;
 640
 641        if (task) {
 642                rcu_read_lock();
 643                nsp = task_nsproxy(task);
 644                if (nsp) {
 645                        ns = nsp->mnt_ns;
 646                        if (ns)
 647                                get_mnt_ns(ns);
 648                }
 649                rcu_read_unlock();
 650                if (ns && get_task_root(task, &root) == 0)
 651                        ret = 0;
 652                put_task_struct(task);
 653        }
 654
 655        if (!ns)
 656                goto err;
 657        if (ret)
 658                goto err_put_ns;
 659
 660        ret = -ENOMEM;
 661        p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
 662        if (!p)
 663                goto err_put_path;
 664
 665        file->private_data = &p->m;
 666        ret = seq_open(file, op);
 667        if (ret)
 668                goto err_free;
 669
 670        p->m.private = p;
 671        p->ns = ns;
 672        p->root = root;
 673        p->event = ns->event;
 674
 675        return 0;
 676
 677 err_free:
 678        kfree(p);
 679 err_put_path:
 680        path_put(&root);
 681 err_put_ns:
 682        put_mnt_ns(ns);
 683 err:
 684        return ret;
 685}
 686
 687static int mounts_release(struct inode *inode, struct file *file)
 688{
 689        struct proc_mounts *p = file->private_data;
 690        path_put(&p->root);
 691        put_mnt_ns(p->ns);
 692        return seq_release(inode, file);
 693}
 694
 695static unsigned mounts_poll(struct file *file, poll_table *wait)
 696{
 697        struct proc_mounts *p = file->private_data;
 698        unsigned res = POLLIN | POLLRDNORM;
 699
 700        poll_wait(file, &p->ns->poll, wait);
 701        if (mnt_had_events(p))
 702                res |= POLLERR | POLLPRI;
 703
 704        return res;
 705}
 706
 707static int mounts_open(struct inode *inode, struct file *file)
 708{
 709        return mounts_open_common(inode, file, &mounts_op);
 710}
 711
 712static const struct file_operations proc_mounts_operations = {
 713        .open           = mounts_open,
 714        .read           = seq_read,
 715        .llseek         = seq_lseek,
 716        .release        = mounts_release,
 717        .poll           = mounts_poll,
 718};
 719
 720static int mountinfo_open(struct inode *inode, struct file *file)
 721{
 722        return mounts_open_common(inode, file, &mountinfo_op);
 723}
 724
 725static const struct file_operations proc_mountinfo_operations = {
 726        .open           = mountinfo_open,
 727        .read           = seq_read,
 728        .llseek         = seq_lseek,
 729        .release        = mounts_release,
 730        .poll           = mounts_poll,
 731};
 732
 733static int mountstats_open(struct inode *inode, struct file *file)
 734{
 735        return mounts_open_common(inode, file, &mountstats_op);
 736}
 737
 738static const struct file_operations proc_mountstats_operations = {
 739        .open           = mountstats_open,
 740        .read           = seq_read,
 741        .llseek         = seq_lseek,
 742        .release        = mounts_release,
 743};
 744
 745#define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 746
 747static ssize_t proc_info_read(struct file * file, char __user * buf,
 748                          size_t count, loff_t *ppos)
 749{
 750        struct inode * inode = file->f_path.dentry->d_inode;
 751        unsigned long page;
 752        ssize_t length;
 753        struct task_struct *task = get_proc_task(inode);
 754
 755        length = -ESRCH;
 756        if (!task)
 757                goto out_no_task;
 758
 759        if (count > PROC_BLOCK_SIZE)
 760                count = PROC_BLOCK_SIZE;
 761
 762        length = -ENOMEM;
 763        if (!(page = __get_free_page(GFP_TEMPORARY)))
 764                goto out;
 765
 766        length = PROC_I(inode)->op.proc_read(task, (char*)page);
 767
 768        if (length >= 0)
 769                length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 770        free_page(page);
 771out:
 772        put_task_struct(task);
 773out_no_task:
 774        return length;
 775}
 776
 777static const struct file_operations proc_info_file_operations = {
 778        .read           = proc_info_read,
 779        .llseek         = generic_file_llseek,
 780};
 781
 782static int proc_single_show(struct seq_file *m, void *v)
 783{
 784        struct inode *inode = m->private;
 785        struct pid_namespace *ns;
 786        struct pid *pid;
 787        struct task_struct *task;
 788        int ret;
 789
 790        ns = inode->i_sb->s_fs_info;
 791        pid = proc_pid(inode);
 792        task = get_pid_task(pid, PIDTYPE_PID);
 793        if (!task)
 794                return -ESRCH;
 795
 796        ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 797
 798        put_task_struct(task);
 799        return ret;
 800}
 801
 802static int proc_single_open(struct inode *inode, struct file *filp)
 803{
 804        return single_open(filp, proc_single_show, inode);
 805}
 806
 807static const struct file_operations proc_single_file_operations = {
 808        .open           = proc_single_open,
 809        .read           = seq_read,
 810        .llseek         = seq_lseek,
 811        .release        = single_release,
 812};
 813
 814static int mem_open(struct inode* inode, struct file* file)
 815{
 816        file->private_data = (void*)((long)current->self_exec_id);
 817        /* OK to pass negative loff_t, we can catch out-of-range */
 818        file->f_mode |= FMODE_UNSIGNED_OFFSET;
 819        return 0;
 820}
 821
 822static ssize_t mem_read(struct file * file, char __user * buf,
 823                        size_t count, loff_t *ppos)
 824{
 825        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 826        char *page;
 827        unsigned long src = *ppos;
 828        int ret = -ESRCH;
 829        struct mm_struct *mm;
 830
 831        if (!task)
 832                goto out_no_task;
 833
 834        ret = -ENOMEM;
 835        page = (char *)__get_free_page(GFP_TEMPORARY);
 836        if (!page)
 837                goto out;
 838
 839        mm = check_mem_permission(task);
 840        ret = PTR_ERR(mm);
 841        if (IS_ERR(mm))
 842                goto out_free;
 843
 844        ret = -EIO;
 845 
 846        if (file->private_data != (void*)((long)current->self_exec_id))
 847                goto out_put;
 848
 849        ret = 0;
 850 
 851        while (count > 0) {
 852                int this_len, retval;
 853
 854                this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 855                retval = access_remote_vm(mm, src, page, this_len, 0);
 856                if (!retval) {
 857                        if (!ret)
 858                                ret = -EIO;
 859                        break;
 860                }
 861
 862                if (copy_to_user(buf, page, retval)) {
 863                        ret = -EFAULT;
 864                        break;
 865                }
 866 
 867                ret += retval;
 868                src += retval;
 869                buf += retval;
 870                count -= retval;
 871        }
 872        *ppos = src;
 873
 874out_put:
 875        mmput(mm);
 876out_free:
 877        free_page((unsigned long) page);
 878out:
 879        put_task_struct(task);
 880out_no_task:
 881        return ret;
 882}
 883
 884static ssize_t mem_write(struct file * file, const char __user *buf,
 885                         size_t count, loff_t *ppos)
 886{
 887        int copied;
 888        char *page;
 889        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 890        unsigned long dst = *ppos;
 891        struct mm_struct *mm;
 892
 893        copied = -ESRCH;
 894        if (!task)
 895                goto out_no_task;
 896
 897        mm = check_mem_permission(task);
 898        copied = PTR_ERR(mm);
 899        if (IS_ERR(mm))
 900                goto out_task;
 901
 902        copied = -EIO;
 903        if (file->private_data != (void *)((long)current->self_exec_id))
 904                goto out_mm;
 905
 906        copied = -ENOMEM;
 907        page = (char *)__get_free_page(GFP_TEMPORARY);
 908        if (!page)
 909                goto out_mm;
 910
 911        copied = 0;
 912        while (count > 0) {
 913                int this_len, retval;
 914
 915                this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 916                if (copy_from_user(page, buf, this_len)) {
 917                        copied = -EFAULT;
 918                        break;
 919                }
 920                retval = access_remote_vm(mm, dst, page, this_len, 1);
 921                if (!retval) {
 922                        if (!copied)
 923                                copied = -EIO;
 924                        break;
 925                }
 926                copied += retval;
 927                buf += retval;
 928                dst += retval;
 929                count -= retval;                        
 930        }
 931        *ppos = dst;
 932        free_page((unsigned long) page);
 933out_mm:
 934        mmput(mm);
 935out_task:
 936        put_task_struct(task);
 937out_no_task:
 938        return copied;
 939}
 940
 941loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 942{
 943        switch (orig) {
 944        case 0:
 945                file->f_pos = offset;
 946                break;
 947        case 1:
 948                file->f_pos += offset;
 949                break;
 950        default:
 951                return -EINVAL;
 952        }
 953        force_successful_syscall_return();
 954        return file->f_pos;
 955}
 956
 957static const struct file_operations proc_mem_operations = {
 958        .llseek         = mem_lseek,
 959        .read           = mem_read,
 960        .write          = mem_write,
 961        .open           = mem_open,
 962};
 963
 964static ssize_t environ_read(struct file *file, char __user *buf,
 965                        size_t count, loff_t *ppos)
 966{
 967        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 968        char *page;
 969        unsigned long src = *ppos;
 970        int ret = -ESRCH;
 971        struct mm_struct *mm;
 972
 973        if (!task)
 974                goto out_no_task;
 975
 976        ret = -ENOMEM;
 977        page = (char *)__get_free_page(GFP_TEMPORARY);
 978        if (!page)
 979                goto out;
 980
 981
 982        mm = mm_for_maps(task);
 983        ret = PTR_ERR(mm);
 984        if (!mm || IS_ERR(mm))
 985                goto out_free;
 986
 987        ret = 0;
 988        while (count > 0) {
 989                int this_len, retval, max_len;
 990
 991                this_len = mm->env_end - (mm->env_start + src);
 992
 993                if (this_len <= 0)
 994                        break;
 995
 996                max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 997                this_len = (this_len > max_len) ? max_len : this_len;
 998
 999                retval = access_process_vm(task, (mm->env_start + src),
1000                        page, this_len, 0);
1001
1002                if (retval <= 0) {
1003                        ret = retval;
1004                        break;
1005                }
1006
1007                if (copy_to_user(buf, page, retval)) {
1008                        ret = -EFAULT;
1009                        break;
1010                }
1011
1012                ret += retval;
1013                src += retval;
1014                buf += retval;
1015                count -= retval;
1016        }
1017        *ppos = src;
1018
1019        mmput(mm);
1020out_free:
1021        free_page((unsigned long) page);
1022out:
1023        put_task_struct(task);
1024out_no_task:
1025        return ret;
1026}
1027
1028static const struct file_operations proc_environ_operations = {
1029        .read           = environ_read,
1030        .llseek         = generic_file_llseek,
1031};
1032
1033static ssize_t oom_adjust_read(struct file *file, char __user *buf,
1034                                size_t count, loff_t *ppos)
1035{
1036        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1037        char buffer[PROC_NUMBUF];
1038        size_t len;
1039        int oom_adjust = OOM_DISABLE;
1040        unsigned long flags;
1041
1042        if (!task)
1043                return -ESRCH;
1044
1045        if (lock_task_sighand(task, &flags)) {
1046                oom_adjust = task->signal->oom_adj;
1047                unlock_task_sighand(task, &flags);
1048        }
1049
1050        put_task_struct(task);
1051
1052        len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
1053
1054        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1055}
1056
1057static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
1058                                size_t count, loff_t *ppos)
1059{
1060        struct task_struct *task;
1061        char buffer[PROC_NUMBUF];
1062        long oom_adjust;
1063        unsigned long flags;
1064        int err;
1065
1066        memset(buffer, 0, sizeof(buffer));
1067        if (count > sizeof(buffer) - 1)
1068                count = sizeof(buffer) - 1;
1069        if (copy_from_user(buffer, buf, count)) {
1070                err = -EFAULT;
1071                goto out;
1072        }
1073
1074        err = strict_strtol(strstrip(buffer), 0, &oom_adjust);
1075        if (err)
1076                goto out;
1077        if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
1078             oom_adjust != OOM_DISABLE) {
1079                err = -EINVAL;
1080                goto out;
1081        }
1082
1083        task = get_proc_task(file->f_path.dentry->d_inode);
1084        if (!task) {
1085                err = -ESRCH;
1086                goto out;
1087        }
1088
1089        task_lock(task);
1090        if (!task->mm) {
1091                err = -EINVAL;
1092                goto err_task_lock;
1093        }
1094
1095        if (!lock_task_sighand(task, &flags)) {
1096                err = -ESRCH;
1097                goto err_task_lock;
1098        }
1099
1100        if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
1101                err = -EACCES;
1102                goto err_sighand;
1103        }
1104
1105        if (oom_adjust != task->signal->oom_adj) {
1106                if (oom_adjust == OOM_DISABLE)
1107                        atomic_inc(&task->mm->oom_disable_count);
1108                if (task->signal->oom_adj == OOM_DISABLE)
1109                        atomic_dec(&task->mm->oom_disable_count);
1110        }
1111
1112        /*
1113         * Warn that /proc/pid/oom_adj is deprecated, see
1114         * Documentation/feature-removal-schedule.txt.
1115         */
1116        printk_once(KERN_WARNING "%s (%d): /proc/%d/oom_adj is deprecated, "
1117                        "please use /proc/%d/oom_score_adj instead.\n",
1118                        current->comm, task_pid_nr(current),
1119                        task_pid_nr(task), task_pid_nr(task));
1120        task->signal->oom_adj = oom_adjust;
1121        /*
1122         * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1123         * value is always attainable.
1124         */
1125        if (task->signal->oom_adj == OOM_ADJUST_MAX)
1126                task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX;
1127        else
1128                task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
1129                                                                -OOM_DISABLE;
1130err_sighand:
1131        unlock_task_sighand(task, &flags);
1132err_task_lock:
1133        task_unlock(task);
1134        put_task_struct(task);
1135out:
1136        return err < 0 ? err : count;
1137}
1138
1139static const struct file_operations proc_oom_adjust_operations = {
1140        .read           = oom_adjust_read,
1141        .write          = oom_adjust_write,
1142        .llseek         = generic_file_llseek,
1143};
1144
1145static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1146                                        size_t count, loff_t *ppos)
1147{
1148        struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1149        char buffer[PROC_NUMBUF];
1150        int oom_score_adj = OOM_SCORE_ADJ_MIN;
1151        unsigned long flags;
1152        size_t len;
1153
1154        if (!task)
1155                return -ESRCH;
1156        if (lock_task_sighand(task, &flags)) {
1157                oom_score_adj = task->signal->oom_score_adj;
1158                unlock_task_sighand(task, &flags);
1159        }
1160        put_task_struct(task);
1161        len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj);
1162        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1163}
1164
1165static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1166                                        size_t count, loff_t *ppos)
1167{
1168        struct task_struct *task;
1169        char buffer[PROC_NUMBUF];
1170        unsigned long flags;
1171        long oom_score_adj;
1172        int err;
1173
1174        memset(buffer, 0, sizeof(buffer));
1175        if (count > sizeof(buffer) - 1)
1176                count = sizeof(buffer) - 1;
1177        if (copy_from_user(buffer, buf, count)) {
1178                err = -EFAULT;
1179                goto out;
1180        }
1181
1182        err = strict_strtol(strstrip(buffer), 0, &oom_score_adj);
1183        if (err)
1184                goto out;
1185        if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1186                        oom_score_adj > OOM_SCORE_ADJ_MAX) {
1187                err = -EINVAL;
1188                goto out;
1189        }
1190
1191        task = get_proc_task(file->f_path.dentry->d_inode);
1192        if (!task) {
1193                err = -ESRCH;
1194                goto out;
1195        }
1196
1197        task_lock(task);
1198        if (!task->mm) {
1199                err = -EINVAL;
1200                goto err_task_lock;
1201        }
1202
1203        if (!lock_task_sighand(task, &flags)) {
1204                err = -ESRCH;
1205                goto err_task_lock;
1206        }
1207
1208        if (oom_score_adj < task->signal->oom_score_adj_min &&
1209                        !capable(CAP_SYS_RESOURCE)) {
1210                err = -EACCES;
1211                goto err_sighand;
1212        }
1213
1214        if (oom_score_adj != task->signal->oom_score_adj) {
1215                if (oom_score_adj == OOM_SCORE_ADJ_MIN)
1216                        atomic_inc(&task->mm->oom_disable_count);
1217                if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1218                        atomic_dec(&task->mm->oom_disable_count);
1219        }
1220        task->signal->oom_score_adj = oom_score_adj;
1221        if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1222                task->signal->oom_score_adj_min = oom_score_adj;
1223        /*
1224         * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
1225         * always attainable.
1226         */
1227        if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1228                task->signal->oom_adj = OOM_DISABLE;
1229        else
1230                task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
1231                                                        OOM_SCORE_ADJ_MAX;
1232err_sighand:
1233        unlock_task_sighand(task, &flags);
1234err_task_lock:
1235        task_unlock(task);
1236        put_task_struct(task);
1237out:
1238        return err < 0 ? err : count;
1239}
1240
1241static const struct file_operations proc_oom_score_adj_operations = {
1242        .read           = oom_score_adj_read,
1243        .write          = oom_score_adj_write,
1244        .llseek         = default_llseek,
1245};
1246
1247#ifdef CONFIG_AUDITSYSCALL
1248#define TMPBUFLEN 21
1249static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1250                                  size_t count, loff_t *ppos)
1251{
1252        struct inode * inode = file->f_path.dentry->d_inode;
1253        struct task_struct *task = get_proc_task(inode);
1254        ssize_t length;
1255        char tmpbuf[TMPBUFLEN];
1256
1257        if (!task)
1258                return -ESRCH;
1259        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1260                                audit_get_loginuid(task));
1261        put_task_struct(task);
1262        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1263}
1264
1265static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1266                                   size_t count, loff_t *ppos)
1267{
1268        struct inode * inode = file->f_path.dentry->d_inode;
1269        char *page, *tmp;
1270        ssize_t length;
1271        uid_t loginuid;
1272
1273        if (!capable(CAP_AUDIT_CONTROL))
1274                return -EPERM;
1275
1276        rcu_read_lock();
1277        if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1278                rcu_read_unlock();
1279                return -EPERM;
1280        }
1281        rcu_read_unlock();
1282
1283        if (count >= PAGE_SIZE)
1284                count = PAGE_SIZE - 1;
1285
1286        if (*ppos != 0) {
1287                /* No partial writes. */
1288                return -EINVAL;
1289        }
1290        page = (char*)__get_free_page(GFP_TEMPORARY);
1291        if (!page)
1292                return -ENOMEM;
1293        length = -EFAULT;
1294        if (copy_from_user(page, buf, count))
1295                goto out_free_page;
1296
1297        page[count] = '\0';
1298        loginuid = simple_strtoul(page, &tmp, 10);
1299        if (tmp == page) {
1300                length = -EINVAL;
1301                goto out_free_page;
1302
1303        }
1304        length = audit_set_loginuid(current, loginuid);
1305        if (likely(length == 0))
1306                length = count;
1307
1308out_free_page:
1309        free_page((unsigned long) page);
1310        return length;
1311}
1312
1313static const struct file_operations proc_loginuid_operations = {
1314        .read           = proc_loginuid_read,
1315        .write          = proc_loginuid_write,
1316        .llseek         = generic_file_llseek,
1317};
1318
1319static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1320                                  size_t count, loff_t *ppos)
1321{
1322        struct inode * inode = file->f_path.dentry->d_inode;
1323        struct task_struct *task = get_proc_task(inode);
1324        ssize_t length;
1325        char tmpbuf[TMPBUFLEN];
1326
1327        if (!task)
1328                return -ESRCH;
1329        length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1330                                audit_get_sessionid(task));
1331        put_task_struct(task);
1332        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1333}
1334
1335static const struct file_operations proc_sessionid_operations = {
1336        .read           = proc_sessionid_read,
1337        .llseek         = generic_file_llseek,
1338};
1339#endif
1340
1341#ifdef CONFIG_FAULT_INJECTION
1342static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1343                                      size_t count, loff_t *ppos)
1344{
1345        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1346        char buffer[PROC_NUMBUF];
1347        size_t len;
1348        int make_it_fail;
1349
1350        if (!task)
1351                return -ESRCH;
1352        make_it_fail = task->make_it_fail;
1353        put_task_struct(task);
1354
1355        len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1356
1357        return simple_read_from_buffer(buf, count, ppos, buffer, len);
1358}
1359
1360static ssize_t proc_fault_inject_write(struct file * file,
1361                        const char __user * buf, size_t count, loff_t *ppos)
1362{
1363        struct task_struct *task;
1364        char buffer[PROC_NUMBUF], *end;
1365        int make_it_fail;
1366
1367        if (!capable(CAP_SYS_RESOURCE))
1368                return -EPERM;
1369        memset(buffer, 0, sizeof(buffer));
1370        if (count > sizeof(buffer) - 1)
1371                count = sizeof(buffer) - 1;
1372        if (copy_from_user(buffer, buf, count))
1373                return -EFAULT;
1374        make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
1375        if (*end)
1376                return -EINVAL;
1377        task = get_proc_task(file->f_dentry->d_inode);
1378        if (!task)
1379                return -ESRCH;
1380        task->make_it_fail = make_it_fail;
1381        put_task_struct(task);
1382
1383        return count;
1384}
1385
1386static const struct file_operations proc_fault_inject_operations = {
1387        .read           = proc_fault_inject_read,
1388        .write          = proc_fault_inject_write,
1389        .llseek         = generic_file_llseek,
1390};
1391#endif
1392
1393
1394#ifdef CONFIG_SCHED_DEBUG
1395/*
1396 * Print out various scheduling related per-task fields:
1397 */
1398static int sched_show(struct seq_file *m, void *v)
1399{
1400        struct inode *inode = m->private;
1401        struct task_struct *p;
1402
1403        p = get_proc_task(inode);
1404        if (!p)
1405                return -ESRCH;
1406        proc_sched_show_task(p, m);
1407
1408        put_task_struct(p);
1409
1410        return 0;
1411}
1412
1413static ssize_t
1414sched_write(struct file *file, const char __user *buf,
1415            size_t count, loff_t *offset)
1416{
1417        struct inode *inode = file->f_path.dentry->d_inode;
1418        struct task_struct *p;
1419
1420        p = get_proc_task(inode);
1421        if (!p)
1422                return -ESRCH;
1423        proc_sched_set_task(p);
1424
1425        put_task_struct(p);
1426
1427        return count;
1428}
1429
1430static int sched_open(struct inode *inode, struct file *filp)
1431{
1432        return single_open(filp, sched_show, inode);
1433}
1434
1435static const struct file_operations proc_pid_sched_operations = {
1436        .open           = sched_open,
1437        .read           = seq_read,
1438        .write          = sched_write,
1439        .llseek         = seq_lseek,
1440        .release        = single_release,
1441};
1442
1443#endif
1444
1445#ifdef CONFIG_SCHED_AUTOGROUP
1446/*
1447 * Print out autogroup related information:
1448 */
1449static int sched_autogroup_show(struct seq_file *m, void *v)
1450{
1451        struct inode *inode = m->private;
1452        struct task_struct *p;
1453
1454        p = get_proc_task(inode);
1455        if (!p)
1456                return -ESRCH;
1457        proc_sched_autogroup_show_task(p, m);
1458
1459        put_task_struct(p);
1460
1461        return 0;
1462}
1463
1464static ssize_t
1465sched_autogroup_write(struct file *file, const char __user *buf,
1466            size_t count, loff_t *offset)
1467{
1468        struct inode *inode = file->f_path.dentry->d_inode;
1469        struct task_struct *p;
1470        char buffer[PROC_NUMBUF];
1471        long nice;
1472        int err;
1473
1474        memset(buffer, 0, sizeof(buffer));
1475        if (count > sizeof(buffer) - 1)
1476                count = sizeof(buffer) - 1;
1477        if (copy_from_user(buffer, buf, count))
1478                return -EFAULT;
1479
1480        err = strict_strtol(strstrip(buffer), 0, &nice);
1481        if (err)
1482                return -EINVAL;
1483
1484        p = get_proc_task(inode);
1485        if (!p)
1486                return -ESRCH;
1487
1488        err = nice;
1489        err = proc_sched_autogroup_set_nice(p, &err);
1490        if (err)
1491                count = err;
1492
1493        put_task_struct(p);
1494
1495        return count;
1496}
1497
1498static int sched_autogroup_open(struct inode *inode, struct file *filp)
1499{
1500        int ret;
1501
1502        ret = single_open(filp, sched_autogroup_show, NULL);
1503        if (!ret) {
1504                struct seq_file *m = filp->private_data;
1505
1506                m->private = inode;
1507        }
1508        return ret;
1509}
1510
1511static const struct file_operations proc_pid_sched_autogroup_operations = {
1512        .open           = sched_autogroup_open,
1513        .read           = seq_read,
1514        .write          = sched_autogroup_write,
1515        .llseek         = seq_lseek,
1516        .release        = single_release,
1517};
1518
1519#endif /* CONFIG_SCHED_AUTOGROUP */
1520
1521static ssize_t comm_write(struct file *file, const char __user *buf,
1522                                size_t count, loff_t *offset)
1523{
1524        struct inode *inode = file->f_path.dentry->d_inode;
1525        struct task_struct *p;
1526        char buffer[TASK_COMM_LEN];
1527
1528        memset(buffer, 0, sizeof(buffer));
1529        if (count > sizeof(buffer) - 1)
1530                count = sizeof(buffer) - 1;
1531        if (copy_from_user(buffer, buf, count))
1532                return -EFAULT;
1533
1534        p = get_proc_task(inode);
1535        if (!p)
1536                return -ESRCH;
1537
1538        if (same_thread_group(current, p))
1539                set_task_comm(p, buffer);
1540        else
1541                count = -EINVAL;
1542
1543        put_task_struct(p);
1544
1545        return count;
1546}
1547
1548static int comm_show(struct seq_file *m, void *v)
1549{
1550        struct inode *inode = m->private;
1551        struct task_struct *p;
1552
1553        p = get_proc_task(inode);
1554        if (!p)
1555                return -ESRCH;
1556
1557        task_lock(p);
1558        seq_printf(m, "%s\n", p->comm);
1559        task_unlock(p);
1560
1561        put_task_struct(p);
1562
1563        return 0;
1564}
1565
1566static int comm_open(struct inode *inode, struct file *filp)
1567{
1568        return single_open(filp, comm_show, inode);
1569}
1570
1571static const struct file_operations proc_pid_set_comm_operations = {
1572        .open           = comm_open,
1573        .read           = seq_read,
1574        .write          = comm_write,
1575        .llseek         = seq_lseek,
1576        .release        = single_release,
1577};
1578
1579/*
1580 * We added or removed a vma mapping the executable. The vmas are only mapped
1581 * during exec and are not mapped with the mmap system call.
1582 * Callers must hold down_write() on the mm's mmap_sem for these
1583 */
1584void added_exe_file_vma(struct mm_struct *mm)
1585{
1586        mm->num_exe_file_vmas++;
1587}
1588
1589void removed_exe_file_vma(struct mm_struct *mm)
1590{
1591        mm->num_exe_file_vmas--;
1592        if ((mm->num_exe_file_vmas == 0) && mm->exe_file){
1593                fput(mm->exe_file);
1594                mm->exe_file = NULL;
1595        }
1596
1597}
1598
1599void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
1600{
1601        if (new_exe_file)
1602                get_file(new_exe_file);
1603        if (mm->exe_file)
1604                fput(mm->exe_file);
1605        mm->exe_file = new_exe_file;
1606        mm->num_exe_file_vmas = 0;
1607}
1608
1609struct file *get_mm_exe_file(struct mm_struct *mm)
1610{
1611        struct file *exe_file;
1612
1613        /* We need mmap_sem to protect against races with removal of
1614         * VM_EXECUTABLE vmas */
1615        down_read(&mm->mmap_sem);
1616        exe_file = mm->exe_file;
1617        if (exe_file)
1618                get_file(exe_file);
1619        up_read(&mm->mmap_sem);
1620        return exe_file;
1621}
1622
1623void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm)
1624{
1625        /* It's safe to write the exe_file pointer without exe_file_lock because
1626         * this is called during fork when the task is not yet in /proc */
1627        newmm->exe_file = get_mm_exe_file(oldmm);
1628}
1629
1630static int proc_exe_link(struct inode *inode, struct path *exe_path)
1631{
1632        struct task_struct *task;
1633        struct mm_struct *mm;
1634        struct file *exe_file;
1635
1636        task = get_proc_task(inode);
1637        if (!task)
1638                return -ENOENT;
1639        mm = get_task_mm(task);
1640        put_task_struct(task);
1641        if (!mm)
1642                return -ENOENT;
1643        exe_file = get_mm_exe_file(mm);
1644        mmput(mm);
1645        if (exe_file) {
1646                *exe_path = exe_file->f_path;
1647                path_get(&exe_file->f_path);
1648                fput(exe_file);
1649                return 0;
1650        } else
1651                return -ENOENT;
1652}
1653
1654static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1655{
1656        struct inode *inode = dentry->d_inode;
1657        int error = -EACCES;
1658
1659        /* We don't need a base pointer in the /proc filesystem */
1660        path_put(&nd->path);
1661
1662        /* Are we allowed to snoop on the tasks file descriptors? */
1663        if (!proc_fd_access_allowed(inode))
1664                goto out;
1665
1666        error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1667out:
1668        return ERR_PTR(error);
1669}
1670
1671static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1672{
1673        char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1674        char *pathname;
1675        int len;
1676
1677        if (!tmp)
1678                return -ENOMEM;
1679
1680        pathname = d_path(path, tmp, PAGE_SIZE);
1681        len = PTR_ERR(pathname);
1682        if (IS_ERR(pathname))
1683                goto out;
1684        len = tmp + PAGE_SIZE - 1 - pathname;
1685
1686        if (len > buflen)
1687                len = buflen;
1688        if (copy_to_user(buffer, pathname, len))
1689                len = -EFAULT;
1690 out:
1691        free_page((unsigned long)tmp);
1692        return len;
1693}
1694
1695static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1696{
1697        int error = -EACCES;
1698        struct inode *inode = dentry->d_inode;
1699        struct path path;
1700
1701        /* Are we allowed to snoop on the tasks file descriptors? */
1702        if (!proc_fd_access_allowed(inode))
1703                goto out;
1704
1705        error = PROC_I(inode)->op.proc_get_link(inode, &path);
1706        if (error)
1707                goto out;
1708
1709        error = do_proc_readlink(&path, buffer, buflen);
1710        path_put(&path);
1711out:
1712        return error;
1713}
1714
1715static const struct inode_operations proc_pid_link_inode_operations = {
1716        .readlink       = proc_pid_readlink,
1717        .follow_link    = proc_pid_follow_link,
1718        .setattr        = proc_setattr,
1719};
1720
1721
1722/* building an inode */
1723
1724static int task_dumpable(struct task_struct *task)
1725{
1726        int dumpable = 0;
1727        struct mm_struct *mm;
1728
1729        task_lock(task);
1730        mm = task->mm;
1731        if (mm)
1732                dumpable = get_dumpable(mm);
1733        task_unlock(task);
1734        if(dumpable == 1)
1735                return 1;
1736        return 0;
1737}
1738
1739
1740static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1741{
1742        struct inode * inode;
1743        struct proc_inode *ei;
1744        const struct cred *cred;
1745
1746        /* We need a new inode */
1747
1748        inode = new_inode(sb);
1749        if (!inode)
1750                goto out;
1751
1752        /* Common stuff */
1753        ei = PROC_I(inode);
1754        inode->i_ino = get_next_ino();
1755        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1756        inode->i_op = &proc_def_inode_operations;
1757
1758        /*
1759         * grab the reference to task.
1760         */
1761        ei->pid = get_task_pid(task, PIDTYPE_PID);
1762        if (!ei->pid)
1763                goto out_unlock;
1764
1765        if (task_dumpable(task)) {
1766                rcu_read_lock();
1767                cred = __task_cred(task);
1768                inode->i_uid = cred->euid;
1769                inode->i_gid = cred->egid;
1770                rcu_read_unlock();
1771        }
1772        security_task_to_inode(task, inode);
1773
1774out:
1775        return inode;
1776
1777out_unlock:
1778        iput(inode);
1779        return NULL;
1780}
1781
1782static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1783{
1784        struct inode *inode = dentry->d_inode;
1785        struct task_struct *task;
1786        const struct cred *cred;
1787
1788        generic_fillattr(inode, stat);
1789
1790        rcu_read_lock();
1791        stat->uid = 0;
1792        stat->gid = 0;
1793        task = pid_task(proc_pid(inode), PIDTYPE_PID);
1794        if (task) {
1795                if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1796                    task_dumpable(task)) {
1797                        cred = __task_cred(task);
1798                        stat->uid = cred->euid;
1799                        stat->gid = cred->egid;
1800                }
1801        }
1802        rcu_read_unlock();
1803        return 0;
1804}
1805
1806/* dentry stuff */
1807
1808/*
1809 *      Exceptional case: normally we are not allowed to unhash a busy
1810 * directory. In this case, however, we can do it - no aliasing problems
1811 * due to the way we treat inodes.
1812 *
1813 * Rewrite the inode's ownerships here because the owning task may have
1814 * performed a setuid(), etc.
1815 *
1816 * Before the /proc/pid/status file was created the only way to read
1817 * the effective uid of a /process was to stat /proc/pid.  Reading
1818 * /proc/pid/status is slow enough that procps and other packages
1819 * kept stating /proc/pid.  To keep the rules in /proc simple I have
1820 * made this apply to all per process world readable and executable
1821 * directories.
1822 */
1823static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1824{
1825        struct inode *inode;
1826        struct task_struct *task;
1827        const struct cred *cred;
1828
1829        if (nd && nd->flags & LOOKUP_RCU)
1830                return -ECHILD;
1831
1832        inode = dentry->d_inode;
1833        task = get_proc_task(inode);
1834
1835        if (task) {
1836                if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1837                    task_dumpable(task)) {
1838                        rcu_read_lock();
1839                        cred = __task_cred(task);
1840                        inode->i_uid = cred->euid;
1841                        inode->i_gid = cred->egid;
1842                        rcu_read_unlock();
1843                } else {
1844                        inode->i_uid = 0;
1845                        inode->i_gid = 0;
1846                }
1847                inode->i_mode &= ~(S_ISUID | S_ISGID);
1848                security_task_to_inode(task, inode);
1849                put_task_struct(task);
1850                return 1;
1851        }
1852        d_drop(dentry);
1853        return 0;
1854}
1855
1856static int pid_delete_dentry(const struct dentry * dentry)
1857{
1858        /* Is the task we represent dead?
1859         * If so, then don't put the dentry on the lru list,
1860         * kill it immediately.
1861         */
1862        return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1863}
1864
1865static const struct dentry_operations pid_dentry_operations =
1866{
1867        .d_revalidate   = pid_revalidate,
1868        .d_delete       = pid_delete_dentry,
1869};
1870
1871/* Lookups */
1872
1873typedef struct dentry *instantiate_t(struct inode *, struct dentry *,
1874                                struct task_struct *, const void *);
1875
1876/*
1877 * Fill a directory entry.
1878 *
1879 * If possible create the dcache entry and derive our inode number and
1880 * file type from dcache entry.
1881 *
1882 * Since all of the proc inode numbers are dynamically generated, the inode
1883 * numbers do not exist until the inode is cache.  This means creating the
1884 * the dcache entry in readdir is necessary to keep the inode numbers
1885 * reported by readdir in sync with the inode numbers reported
1886 * by stat.
1887 */
1888static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1889        char *name, int len,
1890        instantiate_t instantiate, struct task_struct *task, const void *ptr)
1891{
1892        struct dentry *child, *dir = filp->f_path.dentry;
1893        struct inode *inode;
1894        struct qstr qname;
1895        ino_t ino = 0;
1896        unsigned type = DT_UNKNOWN;
1897
1898        qname.name = name;
1899        qname.len  = len;
1900        qname.hash = full_name_hash(name, len);
1901
1902        child = d_lookup(dir, &qname);
1903        if (!child) {
1904                struct dentry *new;
1905                new = d_alloc(dir, &qname);
1906                if (new) {
1907                        child = instantiate(dir->d_inode, new, task, ptr);
1908                        if (child)
1909                                dput(new);
1910                        else
1911                                child = new;
1912                }
1913        }
1914        if (!child || IS_ERR(child) || !child->d_inode)
1915                goto end_instantiate;
1916        inode = child->d_inode;
1917        if (inode) {
1918                ino = inode->i_ino;
1919                type = inode->i_mode >> 12;
1920        }
1921        dput(child);
1922end_instantiate:
1923        if (!ino)
1924                ino = find_inode_number(dir, &qname);
1925        if (!ino)
1926                ino = 1;
1927        return filldir(dirent, name, len, filp->f_pos, ino, type);
1928}
1929
1930static unsigned name_to_int(struct dentry *dentry)
1931{
1932        const char *name = dentry->d_name.name;
1933        int len = dentry->d_name.len;
1934        unsigned n = 0;
1935
1936        if (len > 1 && *name == '0')
1937                goto out;
1938        while (len-- > 0) {
1939                unsigned c = *name++ - '0';
1940                if (c > 9)
1941                        goto out;
1942                if (n >= (~0U-9)/10)
1943                        goto out;
1944                n *= 10;
1945                n += c;
1946        }
1947        return n;
1948out:
1949        return ~0U;
1950}
1951
1952#define PROC_FDINFO_MAX 64
1953
1954static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1955{
1956        struct task_struct *task = get_proc_task(inode);
1957        struct files_struct *files = NULL;
1958        struct file *file;
1959        int fd = proc_fd(inode);
1960
1961        if (task) {
1962                files = get_files_struct(task);
1963                put_task_struct(task);
1964        }
1965        if (files) {
1966                /*
1967                 * We are not taking a ref to the file structure, so we must
1968                 * hold ->file_lock.
1969                 */
1970                spin_lock(&files->file_lock);
1971                file = fcheck_files(files, fd);
1972                if (file) {
1973                        if (path) {
1974                                *path = file->f_path;
1975                                path_get(&file->f_path);
1976                        }
1977                        if (info)
1978                                snprintf(info, PROC_FDINFO_MAX,
1979                                         "pos:\t%lli\n"
1980                                         "flags:\t0%o\n",
1981                                         (long long) file->f_pos,
1982                                         file->f_flags);
1983                        spin_unlock(&files->file_lock);
1984                        put_files_struct(files);
1985                        return 0;
1986                }
1987                spin_unlock(&files->file_lock);
1988                put_files_struct(files);
1989        }
1990        return -ENOENT;
1991}
1992
1993static int proc_fd_link(struct inode *inode, struct path *path)
1994{
1995        return proc_fd_info(inode, path, NULL);
1996}
1997
1998static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1999{
2000        struct inode *inode;
2001        struct task_struct *task;
2002        int fd;
2003        struct files_struct *files;
2004        const struct cred *cred;
2005
2006        if (nd && nd->flags & LOOKUP_RCU)
2007                return -ECHILD;
2008
2009        inode = dentry->d_inode;
2010        task = get_proc_task(inode);
2011        fd = proc_fd(inode);
2012
2013        if (task) {
2014                files = get_files_struct(task);
2015                if (files) {
2016                        rcu_read_lock();
2017                        if (fcheck_files(files, fd)) {
2018                                rcu_read_unlock();
2019                                put_files_struct(files);
2020                                if (task_dumpable(task)) {
2021                                        rcu_read_lock();
2022                                        cred = __task_cred(task);
2023                                        inode->i_uid = cred->euid;
2024                                        inode->i_gid = cred->egid;
2025                                        rcu_read_unlock();
2026                                } else {
2027                                        inode->i_uid = 0;
2028                                        inode->i_gid = 0;
2029                                }
2030                                inode->i_mode &= ~(S_ISUID | S_ISGID);
2031                                security_task_to_inode(task, inode);
2032                                put_task_struct(task);
2033                                return 1;
2034                        }
2035                        rcu_read_unlock();
2036                        put_files_struct(files);
2037                }
2038                put_task_struct(task);
2039        }
2040        d_drop(dentry);
2041        return 0;
2042}
2043
2044static const struct dentry_operations tid_fd_dentry_operations =
2045{
2046        .d_revalidate   = tid_fd_revalidate,
2047        .d_delete       = pid_delete_dentry,
2048};
2049
2050static struct dentry *proc_fd_instantiate(struct inode *dir,
2051        struct dentry *dentry, struct task_struct *task, const void *ptr)
2052{
2053        unsigned fd = *(const unsigned *)ptr;
2054        struct file *file;
2055        struct files_struct *files;
2056        struct inode *inode;
2057        struct proc_inode *ei;
2058        struct dentry *error = ERR_PTR(-ENOENT);
2059
2060        inode = proc_pid_make_inode(dir->i_sb, task);
2061        if (!inode)
2062                goto out;
2063        ei = PROC_I(inode);
2064        ei->fd = fd;
2065        files = get_files_struct(task);
2066        if (!files)
2067                goto out_iput;
2068        inode->i_mode = S_IFLNK;
2069
2070        /*
2071         * We are not taking a ref to the file structure, so we must
2072         * hold ->file_lock.
2073         */
2074        spin_lock(&files->file_lock);
2075        file = fcheck_files(files, fd);
2076        if (!file)
2077                goto out_unlock;
2078        if (file->f_mode & FMODE_READ)
2079                inode->i_mode |= S_IRUSR | S_IXUSR;
2080        if (file->f_mode & FMODE_WRITE)
2081                inode->i_mode |= S_IWUSR | S_IXUSR;
2082        spin_unlock(&files->file_lock);
2083        put_files_struct(files);
2084
2085        inode->i_op = &proc_pid_link_inode_operations;
2086        inode->i_size = 64;
2087        ei->op.proc_get_link = proc_fd_link;
2088        d_set_d_op(dentry, &tid_fd_dentry_operations);
2089        d_add(dentry, inode);
2090        /* Close the race of the process dying before we return the dentry */
2091        if (tid_fd_revalidate(dentry, NULL))
2092                error = NULL;
2093
2094 out:
2095        return error;
2096out_unlock:
2097        spin_unlock(&files->file_lock);
2098        put_files_struct(files);
2099out_iput:
2100        iput(inode);
2101        goto out;
2102}
2103
2104static struct dentry *proc_lookupfd_common(struct inode *dir,
2105                                           struct dentry *dentry,
2106                                           instantiate_t instantiate)
2107{
2108        struct task_struct *task = get_proc_task(dir);
2109        unsigned fd = name_to_int(dentry);
2110        struct dentry *result = ERR_PTR(-ENOENT);
2111
2112        if (!task)
2113                goto out_no_task;
2114        if (fd == ~0U)
2115                goto out;
2116
2117        result = instantiate(dir, dentry, task, &fd);
2118out:
2119        put_task_struct(task);
2120out_no_task:
2121        return result;
2122}
2123
2124static int proc_readfd_common(struct file * filp, void * dirent,
2125                              filldir_t filldir, instantiate_t instantiate)
2126{
2127        struct dentry *dentry = filp->f_path.dentry;
2128        struct inode *inode = dentry->d_inode;
2129        struct task_struct *p = get_proc_task(inode);
2130        unsigned int fd, ino;
2131        int retval;
2132        struct files_struct * files;
2133
2134        retval = -ENOENT;
2135        if (!p)
2136                goto out_no_task;
2137        retval = 0;
2138
2139        fd = filp->f_pos;
2140        switch (fd) {
2141                case 0:
2142                        if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
2143                                goto out;
2144                        filp->f_pos++;
2145                case 1:
2146                        ino = parent_ino(dentry);
2147                        if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
2148                                goto out;
2149                        filp->f_pos++;
2150                default:
2151                        files = get_files_struct(p);
2152                        if (!files)
2153                                goto out;
2154                        rcu_read_lock();
2155                        for (fd = filp->f_pos-2;
2156                             fd < files_fdtable(files)->max_fds;
2157                             fd++, filp->f_pos++) {
2158                                char name[PROC_NUMBUF];
2159                                int len;
2160
2161                                if (!fcheck_files(files, fd))
2162                                        continue;
2163                                rcu_read_unlock();
2164
2165                                len = snprintf(name, sizeof(name), "%d", fd);
2166                                if (proc_fill_cache(filp, dirent, filldir,
2167                                                    name, len, instantiate,
2168                                                    p, &fd) < 0) {
2169                                        rcu_read_lock();
2170                                        break;
2171                                }
2172                                rcu_read_lock();
2173                        }
2174                        rcu_read_unlock();
2175                        put_files_struct(files);
2176        }
2177out:
2178        put_task_struct(p);
2179out_no_task:
2180        return retval;
2181}
2182
2183static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
2184                                    struct nameidata *nd)
2185{
2186        return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
2187}
2188
2189static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
2190{
2191        return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
2192}
2193
2194static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
2195                                      size_t len, loff_t *ppos)
2196{
2197        char tmp[PROC_FDINFO_MAX];
2198        int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
2199        if (!err)
2200                err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
2201        return err;
2202}
2203
2204static const struct file_operations proc_fdinfo_file_operations = {
2205        .open           = nonseekable_open,
2206        .read           = proc_fdinfo_read,
2207        .llseek         = no_llseek,
2208};
2209
2210static const struct file_operations proc_fd_operations = {
2211        .read           = generic_read_dir,
2212        .readdir        = proc_readfd,
2213        .llseek         = default_llseek,
2214};
2215
2216/*
2217 * /proc/pid/fd needs a special permission handler so that a process can still
2218 * access /proc/self/fd after it has executed a setuid().
2219 */
2220static int proc_fd_permission(struct inode *inode, int mask, unsigned int flags)
2221{
2222        int rv;
2223
2224        if (flags & IPERM_FLAG_RCU)
2225                return -ECHILD;
2226        rv = generic_permission(inode, mask, flags, NULL);
2227        if (rv == 0)
2228                return 0;
2229        if (task_pid(current) == proc_pid(inode))
2230                rv = 0;
2231        return rv;
2232}
2233
2234/*
2235 * proc directories can do almost nothing..
2236 */
2237static const struct inode_operations proc_fd_inode_operations = {
2238        .lookup         = proc_lookupfd,
2239        .permission     = proc_fd_permission,
2240        .setattr        = proc_setattr,
2241};
2242
2243static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
2244        struct dentry *dentry, struct task_struct *task, const void *ptr)
2245{
2246        unsigned fd = *(unsigned *)ptr;
2247        struct inode *inode;
2248        struct proc_inode *ei;
2249        struct dentry *error = ERR_PTR(-ENOENT);
2250
2251        inode = proc_pid_make_inode(dir->i_sb, task);
2252        if (!inode)
2253                goto out;
2254        ei = PROC_I(inode);
2255        ei->fd = fd;
2256        inode->i_mode = S_IFREG | S_IRUSR;
2257        inode->i_fop = &proc_fdinfo_file_operations;
2258        d_set_d_op(dentry, &tid_fd_dentry_operations);
2259        d_add(dentry, inode);
2260        /* Close the race of the process dying before we return the dentry */
2261        if (tid_fd_revalidate(dentry, NULL))
2262                error = NULL;
2263
2264 out:
2265        return error;
2266}
2267
2268static struct dentry *proc_lookupfdinfo(struct inode *dir,
2269                                        struct dentry *dentry,
2270                                        struct nameidata *nd)
2271{
2272        return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
2273}
2274
2275static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
2276{
2277        return proc_readfd_common(filp, dirent, filldir,
2278                                  proc_fdinfo_instantiate);
2279}
2280
2281static const struct file_operations proc_fdinfo_operations = {
2282        .read           = generic_read_dir,
2283        .readdir        = proc_readfdinfo,
2284        .llseek         = default_llseek,
2285};
2286
2287/*
2288 * proc directories can do almost nothing..
2289 */
2290static const struct inode_operations proc_fdinfo_inode_operations = {
2291        .lookup         = proc_lookupfdinfo,
2292        .setattr        = proc_setattr,
2293};
2294
2295
2296static struct dentry *proc_pident_instantiate(struct inode *dir,
2297        struct dentry *dentry, struct task_struct *task, const void *ptr)
2298{
2299        const struct pid_entry *p = ptr;
2300        struct inode *inode;
2301        struct proc_inode *ei;
2302        struct dentry *error = ERR_PTR(-ENOENT);
2303
2304        inode = proc_pid_make_inode(dir->i_sb, task);
2305        if (!inode)
2306                goto out;
2307
2308        ei = PROC_I(inode);
2309        inode->i_mode = p->mode;
2310        if (S_ISDIR(inode->i_mode))
2311                inode->i_nlink = 2;     /* Use getattr to fix if necessary */
2312        if (p->iop)
2313                inode->i_op = p->iop;
2314        if (p->fop)
2315                inode->i_fop = p->fop;
2316        ei->op = p->op;
2317        d_set_d_op(dentry, &pid_dentry_operations);
2318        d_add(dentry, inode);
2319        /* Close the race of the process dying before we return the dentry */
2320        if (pid_revalidate(dentry, NULL))
2321                error = NULL;
2322out:
2323        return error;
2324}
2325
2326static struct dentry *proc_pident_lookup(struct inode *dir, 
2327                                         struct dentry *dentry,
2328                                         const struct pid_entry *ents,
2329                                         unsigned int nents)
2330{
2331        struct dentry *error;
2332        struct task_struct *task = get_proc_task(dir);
2333        const struct pid_entry *p, *last;
2334
2335        error = ERR_PTR(-ENOENT);
2336
2337        if (!task)
2338                goto out_no_task;
2339
2340        /*
2341         * Yes, it does not scale. And it should not. Don't add
2342         * new entries into /proc/<tgid>/ without very good reasons.
2343         */
2344        last = &ents[nents - 1];
2345        for (p = ents; p <= last; p++) {
2346                if (p->len != dentry->d_name.len)
2347                        continue;
2348                if (!memcmp(dentry->d_name.name, p->name, p->len))
2349                        break;
2350        }
2351        if (p > last)
2352                goto out;
2353
2354        error = proc_pident_instantiate(dir, dentry, task, p);
2355out:
2356        put_task_struct(task);
2357out_no_task:
2358        return error;
2359}
2360
2361static int proc_pident_fill_cache(struct file *filp, void *dirent,
2362        filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2363{
2364        return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2365                                proc_pident_instantiate, task, p);
2366}
2367
2368static int proc_pident_readdir(struct file *filp,
2369                void *dirent, filldir_t filldir,
2370                const struct pid_entry *ents, unsigned int nents)
2371{
2372        int i;
2373        struct dentry *dentry = filp->f_path.dentry;
2374        struct inode *inode = dentry->d_inode;
2375        struct task_struct *task = get_proc_task(inode);
2376        const struct pid_entry *p, *last;
2377        ino_t ino;
2378        int ret;
2379
2380        ret = -ENOENT;
2381        if (!task)
2382                goto out_no_task;
2383
2384        ret = 0;
2385        i = filp->f_pos;
2386        switch (i) {
2387        case 0:
2388                ino = inode->i_ino;
2389                if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2390                        goto out;
2391                i++;
2392                filp->f_pos++;
2393                /* fall through */
2394        case 1:
2395                ino = parent_ino(dentry);
2396                if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2397                        goto out;
2398                i++;
2399                filp->f_pos++;
2400                /* fall through */
2401        default:
2402                i -= 2;
2403                if (i >= nents) {
2404                        ret = 1;
2405                        goto out;
2406                }
2407                p = ents + i;
2408                last = &ents[nents - 1];
2409                while (p <= last) {
2410                        if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2411                                goto out;
2412                        filp->f_pos++;
2413                        p++;
2414                }
2415        }
2416
2417        ret = 1;
2418out:
2419        put_task_struct(task);
2420out_no_task:
2421        return ret;
2422}
2423
2424#ifdef CONFIG_SECURITY
2425static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2426                                  size_t count, loff_t *ppos)
2427{
2428        struct inode * inode = file->f_path.dentry->d_inode;
2429        char *p = NULL;
2430        ssize_t length;
2431        struct task_struct *task = get_proc_task(inode);
2432
2433        if (!task)
2434                return -ESRCH;
2435
2436        length = security_getprocattr(task,
2437                                      (char*)file->f_path.dentry->d_name.name,
2438                                      &p);
2439        put_task_struct(task);
2440        if (length > 0)
2441                length = simple_read_from_buffer(buf, count, ppos, p, length);
2442        kfree(p);
2443        return length;
2444}
2445
2446static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2447                                   size_t count, loff_t *ppos)
2448{
2449        struct inode * inode = file->f_path.dentry->d_inode;
2450        char *page;
2451        ssize_t length;
2452        struct task_struct *task = get_proc_task(inode);
2453
2454        length = -ESRCH;
2455        if (!task)
2456                goto out_no_task;
2457        if (count > PAGE_SIZE)
2458                count = PAGE_SIZE;
2459
2460        /* No partial writes. */
2461        length = -EINVAL;
2462        if (*ppos != 0)
2463                goto out;
2464
2465        length = -ENOMEM;
2466        page = (char*)__get_free_page(GFP_TEMPORARY);
2467        if (!page)
2468                goto out;
2469
2470        length = -EFAULT;
2471        if (copy_from_user(page, buf, count))
2472                goto out_free;
2473
2474        /* Guard against adverse ptrace interaction */
2475        length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2476        if (length < 0)
2477                goto out_free;
2478
2479        length = security_setprocattr(task,
2480                                      (char*)file->f_path.dentry->d_name.name,
2481                                      (void*)page, count);
2482        mutex_unlock(&task->signal->cred_guard_mutex);
2483out_free:
2484        free_page((unsigned long) page);
2485out:
2486        put_task_struct(task);
2487out_no_task:
2488        return length;
2489}
2490
2491static const struct file_operations proc_pid_attr_operations = {
2492        .read           = proc_pid_attr_read,
2493        .write          = proc_pid_attr_write,
2494        .llseek         = generic_file_llseek,
2495};
2496
2497static const struct pid_entry attr_dir_stuff[] = {
2498        REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2499        REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2500        REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2501        REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2502        REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2503        REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2504};
2505
2506static int proc_attr_dir_readdir(struct file * filp,
2507                             void * dirent, filldir_t filldir)
2508{
2509        return proc_pident_readdir(filp,dirent,filldir,
2510                                   attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2511}
2512
2513static const struct file_operations proc_attr_dir_operations = {
2514        .read           = generic_read_dir,
2515        .readdir        = proc_attr_dir_readdir,
2516        .llseek         = default_llseek,
2517};
2518
2519static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2520                                struct dentry *dentry, struct nameidata *nd)
2521{
2522        return proc_pident_lookup(dir, dentry,
2523                                  attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2524}
2525
2526static const struct inode_operations proc_attr_dir_inode_operations = {
2527        .lookup         = proc_attr_dir_lookup,
2528        .getattr        = pid_getattr,
2529        .setattr        = proc_setattr,
2530};
2531
2532#endif
2533
2534#ifdef CONFIG_ELF_CORE
2535static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2536                                         size_t count, loff_t *ppos)
2537{
2538        struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2539        struct mm_struct *mm;
2540        char buffer[PROC_NUMBUF];
2541        size_t len;
2542        int ret;
2543
2544        if (!task)
2545                return -ESRCH;
2546
2547        ret = 0;
2548        mm = get_task_mm(task);
2549        if (mm) {
2550                len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2551                               ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2552                                MMF_DUMP_FILTER_SHIFT));
2553                mmput(mm);
2554                ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2555        }
2556
2557        put_task_struct(task);
2558
2559        return ret;
2560}
2561
2562static ssize_t proc_coredump_filter_write(struct file *file,
2563                                          const char __user *buf,
2564                                          size_t count,
2565                                          loff_t *ppos)
2566{
2567        struct task_struct *task;
2568        struct mm_struct *mm;
2569        char buffer[PROC_NUMBUF], *end;
2570        unsigned int val;
2571        int ret;
2572        int i;
2573        unsigned long mask;
2574
2575        ret = -EFAULT;
2576        memset(buffer, 0, sizeof(buffer));
2577        if (count > sizeof(buffer) - 1)
2578                count = sizeof(buffer) - 1;
2579        if (copy_from_user(buffer, buf, count))
2580                goto out_no_task;
2581
2582        ret = -EINVAL;
2583        val = (unsigned int)simple_strtoul(buffer, &end, 0);
2584        if (*end == '\n')
2585                end++;
2586        if (end - buffer == 0)
2587                goto out_no_task;
2588
2589        ret = -ESRCH;
2590        task = get_proc_task(file->f_dentry->d_inode);
2591        if (!task)
2592                goto out_no_task;
2593
2594        ret = end - buffer;
2595        mm = get_task_mm(task);
2596        if (!mm)
2597                goto out_no_mm;
2598
2599        for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2600                if (val & mask)
2601                        set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2602                else
2603                        clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2604        }
2605
2606        mmput(mm);
2607 out_no_mm:
2608        put_task_struct(task);
2609 out_no_task:
2610        return ret;
2611}
2612
2613static const struct file_operations proc_coredump_filter_operations = {
2614        .read           = proc_coredump_filter_read,
2615        .write          = proc_coredump_filter_write,
2616        .llseek         = generic_file_llseek,
2617};
2618#endif
2619
2620/*
2621 * /proc/self:
2622 */
2623static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2624                              int buflen)
2625{
2626        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2627        pid_t tgid = task_tgid_nr_ns(current, ns);
2628        char tmp[PROC_NUMBUF];
2629        if (!tgid)
2630                return -ENOENT;
2631        sprintf(tmp, "%d", tgid);
2632        return vfs_readlink(dentry,buffer,buflen,tmp);
2633}
2634
2635static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2636{
2637        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2638        pid_t tgid = task_tgid_nr_ns(current, ns);
2639        char *name = ERR_PTR(-ENOENT);
2640        if (tgid) {
2641                name = __getname();
2642                if (!name)
2643                        name = ERR_PTR(-ENOMEM);
2644                else
2645                        sprintf(name, "%d", tgid);
2646        }
2647        nd_set_link(nd, name);
2648        return NULL;
2649}
2650
2651static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
2652                                void *cookie)
2653{
2654        char *s = nd_get_link(nd);
2655        if (!IS_ERR(s))
2656                __putname(s);
2657}
2658
2659static const struct inode_operations proc_self_inode_operations = {
2660        .readlink       = proc_self_readlink,
2661        .follow_link    = proc_self_follow_link,
2662        .put_link       = proc_self_put_link,
2663};
2664
2665/*
2666 * proc base
2667 *
2668 * These are the directory entries in the root directory of /proc
2669 * that properly belong to the /proc filesystem, as they describe
2670 * describe something that is process related.
2671 */
2672static const struct pid_entry proc_base_stuff[] = {
2673        NOD("self", S_IFLNK|S_IRWXUGO,
2674                &proc_self_inode_operations, NULL, {}),
2675};
2676
2677static struct dentry *proc_base_instantiate(struct inode *dir,
2678        struct dentry *dentry, struct task_struct *task, const void *ptr)
2679{
2680        const struct pid_entry *p = ptr;
2681        struct inode *inode;
2682        struct proc_inode *ei;
2683        struct dentry *error;
2684
2685        /* Allocate the inode */
2686        error = ERR_PTR(-ENOMEM);
2687        inode = new_inode(dir->i_sb);
2688        if (!inode)
2689                goto out;
2690
2691        /* Initialize the inode */
2692        ei = PROC_I(inode);
2693        inode->i_ino = get_next_ino();
2694        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2695
2696        /*
2697         * grab the reference to the task.
2698         */
2699        ei->pid = get_task_pid(task, PIDTYPE_PID);
2700        if (!ei->pid)
2701                goto out_iput;
2702
2703        inode->i_mode = p->mode;
2704        if (S_ISDIR(inode->i_mode))
2705                inode->i_nlink = 2;
2706        if (S_ISLNK(inode->i_mode))
2707                inode->i_size = 64;
2708        if (p->iop)
2709                inode->i_op = p->iop;
2710        if (p->fop)
2711                inode->i_fop = p->fop;
2712        ei->op = p->op;
2713        d_add(dentry, inode);
2714        error = NULL;
2715out:
2716        return error;
2717out_iput:
2718        iput(inode);
2719        goto out;
2720}
2721
2722static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2723{
2724        struct dentry *error;
2725        struct task_struct *task = get_proc_task(dir);
2726        const struct pid_entry *p, *last;
2727
2728        error = ERR_PTR(-ENOENT);
2729
2730        if (!task)
2731                goto out_no_task;
2732
2733        /* Lookup the directory entry */
2734        last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2735        for (p = proc_base_stuff; p <= last; p++) {
2736                if (p->len != dentry->d_name.len)
2737                        continue;
2738                if (!memcmp(dentry->d_name.name, p->name, p->len))
2739                        break;
2740        }
2741        if (p > last)
2742                goto out;
2743
2744        error = proc_base_instantiate(dir, dentry, task, p);
2745
2746out:
2747        put_task_struct(task);
2748out_no_task:
2749        return error;
2750}
2751
2752static int proc_base_fill_cache(struct file *filp, void *dirent,
2753        filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2754{
2755        return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2756                                proc_base_instantiate, task, p);
2757}
2758
2759#ifdef CONFIG_TASK_IO_ACCOUNTING
2760static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2761{
2762        struct task_io_accounting acct = task->ioac;
2763        unsigned long flags;
2764
2765        if (whole && lock_task_sighand(task, &flags)) {
2766                struct task_struct *t = task;
2767
2768                task_io_accounting_add(&acct, &task->signal->ioac);
2769                while_each_thread(task, t)
2770                        task_io_accounting_add(&acct, &t->ioac);
2771
2772                unlock_task_sighand(task, &flags);
2773        }
2774        return sprintf(buffer,
2775                        "rchar: %llu\n"
2776                        "wchar: %llu\n"
2777                        "syscr: %llu\n"
2778                        "syscw: %llu\n"
2779                        "read_bytes: %llu\n"
2780                        "write_bytes: %llu\n"
2781                        "cancelled_write_bytes: %llu\n",
2782                        (unsigned long long)acct.rchar,
2783                        (unsigned long long)acct.wchar,
2784                        (unsigned long long)acct.syscr,
2785                        (unsigned long long)acct.syscw,
2786                        (unsigned long long)acct.read_bytes,
2787                        (unsigned long long)acct.write_bytes,
2788                        (unsigned long long)acct.cancelled_write_bytes);
2789}
2790
2791static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2792{
2793        return do_io_accounting(task, buffer, 0);
2794}
2795
2796static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2797{
2798        return do_io_accounting(task, buffer, 1);
2799}
2800#endif /* CONFIG_TASK_IO_ACCOUNTING */
2801
2802static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2803                                struct pid *pid, struct task_struct *task)
2804{
2805        int err = lock_trace(task);
2806        if (!err) {
2807                seq_printf(m, "%08x\n", task->personality);
2808                unlock_trace(task);
2809        }
2810        return err;
2811}
2812
2813/*
2814 * Thread groups
2815 */
2816static const struct file_operations proc_task_operations;
2817static const struct inode_operations proc_task_inode_operations;
2818
2819static const struct pid_entry tgid_base_stuff[] = {
2820        DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2821        DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2822        DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2823#ifdef CONFIG_NET
2824        DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2825#endif
2826        REG("environ",    S_IRUSR, proc_environ_operations),
2827        INF("auxv",       S_IRUSR, proc_pid_auxv),
2828        ONE("status",     S_IRUGO, proc_pid_status),
2829        ONE("personality", S_IRUGO, proc_pid_personality),
2830        INF("limits",     S_IRUGO, proc_pid_limits),
2831#ifdef CONFIG_SCHED_DEBUG
2832        REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2833#endif
2834#ifdef CONFIG_SCHED_AUTOGROUP
2835        REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2836#endif
2837        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2838#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2839        INF("syscall",    S_IRUGO, proc_pid_syscall),
2840#endif
2841        INF("cmdline",    S_IRUGO, proc_pid_cmdline),
2842        ONE("stat",       S_IRUGO, proc_tgid_stat),
2843        ONE("statm",      S_IRUGO, proc_pid_statm),
2844        REG("maps",       S_IRUGO, proc_maps_operations),
2845#ifdef CONFIG_NUMA
2846        REG("numa_maps",  S_IRUGO, proc_numa_maps_operations),
2847#endif
2848        REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2849        LNK("cwd",        proc_cwd_link),
2850        LNK("root",       proc_root_link),
2851        LNK("exe",        proc_exe_link),
2852        REG("mounts",     S_IRUGO, proc_mounts_operations),
2853        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2854        REG("mountstats", S_IRUSR, proc_mountstats_operations),
2855#ifdef CONFIG_PROC_PAGE_MONITOR
2856        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2857        REG("smaps",      S_IRUGO, proc_smaps_operations),
2858        REG("pagemap",    S_IRUGO, proc_pagemap_operations),
2859#endif
2860#ifdef CONFIG_SECURITY
2861        DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2862#endif
2863#ifdef CONFIG_KALLSYMS
2864        INF("wchan",      S_IRUGO, proc_pid_wchan),
2865#endif
2866#ifdef CONFIG_STACKTRACE
2867        ONE("stack",      S_IRUGO, proc_pid_stack),
2868#endif
2869#ifdef CONFIG_SCHEDSTATS
2870        INF("schedstat",  S_IRUGO, proc_pid_schedstat),
2871#endif
2872#ifdef CONFIG_LATENCYTOP
2873        REG("latency",  S_IRUGO, proc_lstats_operations),
2874#endif
2875#ifdef CONFIG_PROC_PID_CPUSET
2876        REG("cpuset",     S_IRUGO, proc_cpuset_operations),
2877#endif
2878#ifdef CONFIG_CGROUPS
2879        REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2880#endif
2881        INF("oom_score",  S_IRUGO, proc_oom_score),
2882        REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
2883        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2884#ifdef CONFIG_AUDITSYSCALL
2885        REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2886        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2887#endif
2888#ifdef CONFIG_FAULT_INJECTION
2889        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2890#endif
2891#ifdef CONFIG_ELF_CORE
2892        REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2893#endif
2894#ifdef CONFIG_TASK_IO_ACCOUNTING
2895        INF("io",       S_IRUGO, proc_tgid_io_accounting),
2896#endif
2897};
2898
2899static int proc_tgid_base_readdir(struct file * filp,
2900                             void * dirent, filldir_t filldir)
2901{
2902        return proc_pident_readdir(filp,dirent,filldir,
2903                                   tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2904}
2905
2906static const struct file_operations proc_tgid_base_operations = {
2907        .read           = generic_read_dir,
2908        .readdir        = proc_tgid_base_readdir,
2909        .llseek         = default_llseek,
2910};
2911
2912static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2913        return proc_pident_lookup(dir, dentry,
2914                                  tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2915}
2916
2917static const struct inode_operations proc_tgid_base_inode_operations = {
2918        .lookup         = proc_tgid_base_lookup,
2919        .getattr        = pid_getattr,
2920        .setattr        = proc_setattr,
2921};
2922
2923static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2924{
2925        struct dentry *dentry, *leader, *dir;
2926        char buf[PROC_NUMBUF];
2927        struct qstr name;
2928
2929        name.name = buf;
2930        name.len = snprintf(buf, sizeof(buf), "%d", pid);
2931        dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2932        if (dentry) {
2933                shrink_dcache_parent(dentry);
2934                d_drop(dentry);
2935                dput(dentry);
2936        }
2937
2938        name.name = buf;
2939        name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2940        leader = d_hash_and_lookup(mnt->mnt_root, &name);
2941        if (!leader)
2942                goto out;
2943
2944        name.name = "task";
2945        name.len = strlen(name.name);
2946        dir = d_hash_and_lookup(leader, &name);
2947        if (!dir)
2948                goto out_put_leader;
2949
2950        name.name = buf;
2951        name.len = snprintf(buf, sizeof(buf), "%d", pid);
2952        dentry = d_hash_and_lookup(dir, &name);
2953        if (dentry) {
2954                shrink_dcache_parent(dentry);
2955                d_drop(dentry);
2956                dput(dentry);
2957        }
2958
2959        dput(dir);
2960out_put_leader:
2961        dput(leader);
2962out:
2963        return;
2964}
2965
2966/**
2967 * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2968 * @task: task that should be flushed.
2969 *
2970 * When flushing dentries from proc, one needs to flush them from global
2971 * proc (proc_mnt) and from all the namespaces' procs this task was seen
2972 * in. This call is supposed to do all of this job.
2973 *
2974 * Looks in the dcache for
2975 * /proc/@pid
2976 * /proc/@tgid/task/@pid
2977 * if either directory is present flushes it and all of it'ts children
2978 * from the dcache.
2979 *
2980 * It is safe and reasonable to cache /proc entries for a task until
2981 * that task exits.  After that they just clog up the dcache with
2982 * useless entries, possibly causing useful dcache entries to be
2983 * flushed instead.  This routine is proved to flush those useless
2984 * dcache entries at process exit time.
2985 *
2986 * NOTE: This routine is just an optimization so it does not guarantee
2987 *       that no dcache entries will exist at process exit time it
2988 *       just makes it very unlikely that any will persist.
2989 */
2990
2991void proc_flush_task(struct task_struct *task)
2992{
2993        int i;
2994        struct pid *pid, *tgid;
2995        struct upid *upid;
2996
2997        pid = task_pid(task);
2998        tgid = task_tgid(task);
2999
3000        for (i = 0; i <= pid->level; i++) {
3001                upid = &pid->numbers[i];
3002                proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3003                                        tgid->numbers[i].nr);
3004        }
3005
3006        upid = &pid->numbers[pid->level];
3007        if (upid->nr == 1)
3008                pid_ns_release_proc(upid->ns);
3009}
3010
3011static struct dentry *proc_pid_instantiate(struct inode *dir,
3012                                           struct dentry * dentry,
3013                                           struct task_struct *task, const void *ptr)
3014{
3015        struct dentry *error = ERR_PTR(-ENOENT);
3016        struct inode *inode;
3017
3018        inode = proc_pid_make_inode(dir->i_sb, task);
3019        if (!inode)
3020                goto out;
3021
3022        inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3023        inode->i_op = &proc_tgid_base_inode_operations;
3024        inode->i_fop = &proc_tgid_base_operations;
3025        inode->i_flags|=S_IMMUTABLE;
3026
3027        inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
3028                ARRAY_SIZE(tgid_base_stuff));
3029
3030        d_set_d_op(dentry, &pid_dentry_operations);
3031
3032        d_add(dentry, inode);
3033        /* Close the race of the process dying before we return the dentry */
3034        if (pid_revalidate(dentry, NULL))
3035                error = NULL;
3036out:
3037        return error;
3038}
3039
3040struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3041{
3042        struct dentry *result;
3043        struct task_struct *task;
3044        unsigned tgid;
3045        struct pid_namespace *ns;
3046
3047        result = proc_base_lookup(dir, dentry);
3048        if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
3049                goto out;
3050
3051        tgid = name_to_int(dentry);
3052        if (tgid == ~0U)
3053                goto out;
3054
3055        ns = dentry->d_sb->s_fs_info;
3056        rcu_read_lock();
3057        task = find_task_by_pid_ns(tgid, ns);
3058        if (task)
3059                get_task_struct(task);
3060        rcu_read_unlock();
3061        if (!task)
3062                goto out;
3063
3064        result = proc_pid_instantiate(dir, dentry, task, NULL);
3065        put_task_struct(task);
3066out:
3067        return result;
3068}
3069
3070/*
3071 * Find the first task with tgid >= tgid
3072 *
3073 */
3074struct tgid_iter {
3075        unsigned int tgid;
3076        struct task_struct *task;
3077};
3078static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3079{
3080        struct pid *pid;
3081
3082        if (iter.task)
3083                put_task_struct(iter.task);
3084        rcu_read_lock();
3085retry:
3086        iter.task = NULL;
3087        pid = find_ge_pid(iter.tgid, ns);
3088        if (pid) {
3089                iter.tgid = pid_nr_ns(pid, ns);
3090                iter.task = pid_task(pid, PIDTYPE_PID);
3091                /* What we to know is if the pid we have find is the
3092                 * pid of a thread_group_leader.  Testing for task
3093                 * being a thread_group_leader is the obvious thing
3094                 * todo but there is a window when it fails, due to
3095                 * the pid transfer logic in de_thread.
3096                 *
3097                 * So we perform the straight forward test of seeing
3098                 * if the pid we have found is the pid of a thread
3099                 * group leader, and don't worry if the task we have
3100                 * found doesn't happen to be a thread group leader.
3101                 * As we don't care in the case of readdir.
3102                 */
3103                if (!iter.task || !has_group_leader_pid(iter.task)) {
3104                        iter.tgid += 1;
3105                        goto retry;
3106                }
3107                get_task_struct(iter.task);
3108        }
3109        rcu_read_unlock();
3110        return iter;
3111}
3112
3113#define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
3114
3115static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3116        struct tgid_iter iter)
3117{
3118        char name[PROC_NUMBUF];
3119        int len = snprintf(name, sizeof(name), "%d", iter.tgid);
3120        return proc_fill_cache(filp, dirent, filldir, name, len,
3121                                proc_pid_instantiate, iter.task, NULL);
3122}
3123
3124/* for the /proc/ directory itself, after non-process stuff has been done */
3125int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
3126{
3127        unsigned int nr;
3128        struct task_struct *reaper;
3129        struct tgid_iter iter;
3130        struct pid_namespace *ns;
3131
3132        if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
3133                goto out_no_task;
3134        nr = filp->f_pos - FIRST_PROCESS_ENTRY;
3135
3136        reaper = get_proc_task(filp->f_path.dentry->d_inode);
3137        if (!reaper)
3138                goto out_no_task;
3139
3140        for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
3141                const struct pid_entry *p = &proc_base_stuff[nr];
3142                if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
3143                        goto out;
3144        }
3145
3146        ns = filp->f_dentry->d_sb->s_fs_info;
3147        iter.task = NULL;
3148        iter.tgid = filp->f_pos - TGID_OFFSET;
3149        for (iter = next_tgid(ns, iter);
3150             iter.task;
3151             iter.tgid += 1, iter = next_tgid(ns, iter)) {
3152                filp->f_pos = iter.tgid + TGID_OFFSET;
3153                if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
3154                        put_task_struct(iter.task);
3155                        goto out;
3156                }
3157        }
3158        filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
3159out:
3160        put_task_struct(reaper);
3161out_no_task:
3162        return 0;
3163}
3164
3165/*
3166 * Tasks
3167 */
3168static const struct pid_entry tid_base_stuff[] = {
3169        DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3170        DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3171        REG("environ",   S_IRUSR, proc_environ_operations),
3172        INF("auxv",      S_IRUSR, proc_pid_auxv),
3173        ONE("status",    S_IRUGO, proc_pid_status),
3174        ONE("personality", S_IRUGO, proc_pid_personality),
3175        INF("limits",    S_IRUGO, proc_pid_limits),
3176#ifdef CONFIG_SCHED_DEBUG
3177        REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3178#endif
3179        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3180#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3181        INF("syscall",   S_IRUGO, proc_pid_syscall),
3182#endif
3183        INF("cmdline",   S_IRUGO, proc_pid_cmdline),
3184        ONE("stat",      S_IRUGO, proc_tid_stat),
3185        ONE("statm",     S_IRUGO, proc_pid_statm),
3186        REG("maps",      S_IRUGO, proc_maps_operations),
3187#ifdef CONFIG_NUMA
3188        REG("numa_maps", S_IRUGO, proc_numa_maps_operations),
3189#endif
3190        REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3191        LNK("cwd",       proc_cwd_link),
3192        LNK("root",      proc_root_link),
3193        LNK("exe",       proc_exe_link),
3194        REG("mounts",    S_IRUGO, proc_mounts_operations),
3195        REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3196#ifdef CONFIG_PROC_PAGE_MONITOR
3197        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3198        REG("smaps",     S_IRUGO, proc_smaps_operations),
3199        REG("pagemap",    S_IRUGO, proc_pagemap_operations),
3200#endif
3201#ifdef CONFIG_SECURITY
3202        DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3203#endif
3204#ifdef CONFIG_KALLSYMS
3205        INF("wchan",     S_IRUGO, proc_pid_wchan),
3206#endif
3207#ifdef CONFIG_STACKTRACE
3208        ONE("stack",      S_IRUGO, proc_pid_stack),
3209#endif
3210#ifdef CONFIG_SCHEDSTATS
3211        INF("schedstat", S_IRUGO, proc_pid_schedstat),
3212#endif
3213#ifdef CONFIG_LATENCYTOP
3214        REG("latency",  S_IRUGO, proc_lstats_operations),
3215#endif
3216#ifdef CONFIG_PROC_PID_CPUSET
3217        REG("cpuset",    S_IRUGO, proc_cpuset_operations),
3218#endif
3219#ifdef CONFIG_CGROUPS
3220        REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3221#endif
3222        INF("oom_score", S_IRUGO, proc_oom_score),
3223        REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
3224        REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3225#ifdef CONFIG_AUDITSYSCALL
3226        REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3227        REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3228#endif
3229#ifdef CONFIG_FAULT_INJECTION
3230        REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3231#endif
3232#ifdef CONFIG_TASK_IO_ACCOUNTING
3233        INF("io",       S_IRUGO, proc_tid_io_accounting),
3234#endif
3235};
3236
3237static int proc_tid_base_readdir(struct file * filp,
3238                             void * dirent, filldir_t filldir)
3239{
3240        return proc_pident_readdir(filp,dirent,filldir,
3241                                   tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
3242}
3243
3244static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
3245        return proc_pident_lookup(dir, dentry,
3246                                  tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3247}
3248
3249static const struct file_operations proc_tid_base_operations = {
3250        .read           = generic_read_dir,
3251        .readdir        = proc_tid_base_readdir,
3252        .llseek         = default_llseek,
3253};
3254
3255static const struct inode_operations proc_tid_base_inode_operations = {
3256        .lookup         = proc_tid_base_lookup,
3257        .getattr        = pid_getattr,
3258        .setattr        = proc_setattr,
3259};
3260
3261static struct dentry *proc_task_instantiate(struct inode *dir,
3262        struct dentry *dentry, struct task_struct *task, const void *ptr)
3263{
3264        struct dentry *error = ERR_PTR(-ENOENT);
3265        struct inode *inode;
3266        inode = proc_pid_make_inode(dir->i_sb, task);
3267
3268        if (!inode)
3269                goto out;
3270        inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3271        inode->i_op = &proc_tid_base_inode_operations;
3272        inode->i_fop = &proc_tid_base_operations;
3273        inode->i_flags|=S_IMMUTABLE;
3274
3275        inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
3276                ARRAY_SIZE(tid_base_stuff));
3277
3278        d_set_d_op(dentry, &pid_dentry_operations);
3279
3280        d_add(dentry, inode);
3281        /* Close the race of the process dying before we return the dentry */
3282        if (pid_revalidate(dentry, NULL))
3283                error = NULL;
3284out:
3285        return error;
3286}
3287
3288static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3289{
3290        struct dentry *result = ERR_PTR(-ENOENT);
3291        struct task_struct *task;
3292        struct task_struct *leader = get_proc_task(dir);
3293        unsigned tid;
3294        struct pid_namespace *ns;
3295
3296        if (!leader)
3297                goto out_no_task;
3298
3299        tid = name_to_int(dentry);
3300        if (tid == ~0U)
3301                goto out;
3302
3303        ns = dentry->d_sb->s_fs_info;
3304        rcu_read_lock();
3305        task = find_task_by_pid_ns(tid, ns);
3306        if (task)
3307                get_task_struct(task);
3308        rcu_read_unlock();
3309        if (!task)
3310                goto out;
3311        if (!same_thread_group(leader, task))
3312                goto out_drop_task;
3313
3314        result = proc_task_instantiate(dir, dentry, task, NULL);
3315out_drop_task:
3316        put_task_struct(task);
3317out:
3318        put_task_struct(leader);
3319out_no_task:
3320        return result;
3321}
3322
3323/*
3324 * Find the first tid of a thread group to return to user space.
3325 *
3326 * Usually this is just the thread group leader, but if the users
3327 * buffer was too small or there was a seek into the middle of the
3328 * directory we have more work todo.
3329 *
3330 * In the case of a short read we start with find_task_by_pid.
3331 *
3332 * In the case of a seek we start with the leader and walk nr
3333 * threads past it.
3334 */
3335static struct task_struct *first_tid(struct task_struct *leader,
3336                int tid, int nr, struct pid_namespace *ns)
3337{
3338        struct task_struct *pos;
3339
3340        rcu_read_lock();
3341        /* Attempt to start with the pid of a thread */
3342        if (tid && (nr > 0)) {
3343                pos = find_task_by_pid_ns(tid, ns);
3344                if (pos && (pos->group_leader == leader))
3345                        goto found;
3346        }
3347
3348        /* If nr exceeds the number of threads there is nothing todo */
3349        pos = NULL;
3350        if (nr && nr >= get_nr_threads(leader))
3351                goto out;
3352
3353        /* If we haven't found our starting place yet start
3354         * with the leader and walk nr threads forward.
3355         */
3356        for (pos = leader; nr > 0; --nr) {
3357                pos = next_thread(pos);
3358                if (pos == leader) {
3359                        pos = NULL;
3360                        goto out;
3361                }
3362        }
3363found:
3364        get_task_struct(pos);
3365out:
3366        rcu_read_unlock();
3367        return pos;
3368}
3369
3370/*
3371 * Find the next thread in the thread list.
3372 * Return NULL if there is an error or no next thread.
3373 *
3374 * The reference to the input task_struct is released.
3375 */
3376static struct task_struct *next_tid(struct task_struct *start)
3377{
3378        struct task_struct *pos = NULL;
3379        rcu_read_lock();
3380        if (pid_alive(start)) {
3381                pos = next_thread(start);
3382                if (thread_group_leader(pos))
3383                        pos = NULL;
3384                else
3385                        get_task_struct(pos);
3386        }
3387        rcu_read_unlock();
3388        put_task_struct(start);
3389        return pos;
3390}
3391
3392static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3393        struct task_struct *task, int tid)
3394{
3395        char name[PROC_NUMBUF];
3396        int len = snprintf(name, sizeof(name), "%d", tid);
3397        return proc_fill_cache(filp, dirent, filldir, name, len,
3398                                proc_task_instantiate, task, NULL);
3399}
3400
3401/* for the /proc/TGID/task/ directories */
3402static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3403{
3404        struct dentry *dentry = filp->f_path.dentry;
3405        struct inode *inode = dentry->d_inode;
3406        struct task_struct *leader = NULL;
3407        struct task_struct *task;
3408        int retval = -ENOENT;
3409        ino_t ino;
3410        int tid;
3411        struct pid_namespace *ns;
3412
3413        task = get_proc_task(inode);
3414        if (!task)
3415                goto out_no_task;
3416        rcu_read_lock();
3417        if (pid_alive(task)) {
3418                leader = task->group_leader;
3419                get_task_struct(leader);
3420        }
3421        rcu_read_unlock();
3422        put_task_struct(task);
3423        if (!leader)
3424                goto out_no_task;
3425        retval = 0;
3426
3427        switch ((unsigned long)filp->f_pos) {
3428        case 0:
3429                ino = inode->i_ino;
3430                if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) < 0)
3431                        goto out;
3432                filp->f_pos++;
3433                /* fall through */
3434        case 1:
3435                ino = parent_ino(dentry);
3436                if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) < 0)
3437                        goto out;
3438                filp->f_pos++;
3439                /* fall through */
3440        }
3441
3442        /* f_version caches the tgid value that the last readdir call couldn't
3443         * return. lseek aka telldir automagically resets f_version to 0.
3444         */
3445        ns = filp->f_dentry->d_sb->s_fs_info;
3446        tid = (int)filp->f_version;
3447        filp->f_version = 0;
3448        for (task = first_tid(leader, tid, filp->f_pos - 2, ns);
3449             task;
3450             task = next_tid(task), filp->f_pos++) {
3451                tid = task_pid_nr_ns(task, ns);
3452                if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3453                        /* returning this tgid failed, save it as the first
3454                         * pid for the next readir call */
3455                        filp->f_version = (u64)tid;
3456                        put_task_struct(task);
3457                        break;
3458                }
3459        }
3460out:
3461        put_task_struct(leader);
3462out_no_task:
3463        return retval;
3464}
3465
3466static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3467{
3468        struct inode *inode = dentry->d_inode;
3469        struct task_struct *p = get_proc_task(inode);
3470        generic_fillattr(inode, stat);
3471
3472        if (p) {
3473                stat->nlink += get_nr_threads(p);
3474                put_task_struct(p);
3475        }
3476
3477        return 0;
3478}
3479
3480static const struct inode_operations proc_task_inode_operations = {
3481        .lookup         = proc_task_lookup,
3482        .getattr        = proc_task_getattr,
3483        .setattr        = proc_setattr,
3484};
3485
3486static const struct file_operations proc_task_operations = {
3487        .read           = generic_read_dir,
3488        .readdir        = proc_task_readdir,
3489        .llseek         = default_llseek,
3490};
3491