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