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