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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/config.h>
  53 #include <linux/errno.h>
  54 #include <linux/time.h>
  55 #include <linux/proc_fs.h>
  56 #include <linux/stat.h>
  57 #include <linux/init.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/namespace.h>
  63 #include <linux/mm.h>
  64 #include <linux/smp_lock.h>
  65 #include <linux/rcupdate.h>
  66 #include <linux/kallsyms.h>
  67 #include <linux/mount.h>
  68 #include <linux/security.h>
  69 #include <linux/ptrace.h>
  70 #include <linux/seccomp.h>
  71 #include <linux/cpuset.h>
  72 #include <linux/audit.h>
  73 #include "internal.h"
  74
  75 /*
  76  * For hysterical raisins we keep the same inumbers as in the old procfs.
  77  * Feel free to change the macro below - just keep the range distinct from
  78  * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
  79  * As soon as we'll get a separate superblock we will be able to forget
  80  * about magical ranges too.
  81  */
  82
  83 #define fake_ino(pid,ino) (((pid)<<16)|(ino))
  84
  85 enum pid_directory_inos {
  86         PROC_TGID_INO = 2,
  87         PROC_TGID_TASK,
  88         PROC_TGID_STATUS,
  89         PROC_TGID_MEM,
  90 #ifdef CONFIG_SECCOMP
  91         PROC_TGID_SECCOMP,
  92 #endif
  93         PROC_TGID_CWD,
  94         PROC_TGID_ROOT,
  95         PROC_TGID_EXE,
  96         PROC_TGID_FD,
  97         PROC_TGID_ENVIRON,
  98         PROC_TGID_AUXV,
  99         PROC_TGID_CMDLINE,
 100         PROC_TGID_STAT,
 101         PROC_TGID_STATM,
 102         PROC_TGID_MAPS,
 103         PROC_TGID_NUMA_MAPS,
 104         PROC_TGID_MOUNTS,
 105         PROC_TGID_WCHAN,
 106         PROC_TGID_SMAPS,
 107 #ifdef CONFIG_SCHEDSTATS
 108         PROC_TGID_SCHEDSTAT,
 109 #endif
 110 #ifdef CONFIG_CPUSETS
 111         PROC_TGID_CPUSET,
 112 #endif
 113 #ifdef CONFIG_SECURITY
 114         PROC_TGID_ATTR,
 115         PROC_TGID_ATTR_CURRENT,
 116         PROC_TGID_ATTR_PREV,
 117         PROC_TGID_ATTR_EXEC,
 118         PROC_TGID_ATTR_FSCREATE,
 119 #endif
 120 #ifdef CONFIG_AUDITSYSCALL
 121         PROC_TGID_LOGINUID,
 122 #endif
 123         PROC_TGID_OOM_SCORE,
 124         PROC_TGID_OOM_ADJUST,
 125         PROC_TID_INO,
 126         PROC_TID_STATUS,
 127         PROC_TID_MEM,
 128 #ifdef CONFIG_SECCOMP
 129         PROC_TID_SECCOMP,
 130 #endif
 131         PROC_TID_CWD,
 132         PROC_TID_ROOT,
 133         PROC_TID_EXE,
 134         PROC_TID_FD,
 135         PROC_TID_ENVIRON,
 136         PROC_TID_AUXV,
 137         PROC_TID_CMDLINE,
 138         PROC_TID_STAT,
 139         PROC_TID_STATM,
 140         PROC_TID_MAPS,
 141         PROC_TID_NUMA_MAPS,
 142         PROC_TID_MOUNTS,
 143         PROC_TID_WCHAN,
 144         PROC_TID_SMAPS,
 145 #ifdef CONFIG_SCHEDSTATS
 146         PROC_TID_SCHEDSTAT,
 147 #endif
 148 #ifdef CONFIG_CPUSETS
 149         PROC_TID_CPUSET,
 150 #endif
 151 #ifdef CONFIG_SECURITY
 152         PROC_TID_ATTR,
 153         PROC_TID_ATTR_CURRENT,
 154         PROC_TID_ATTR_PREV,
 155         PROC_TID_ATTR_EXEC,
 156         PROC_TID_ATTR_FSCREATE,
 157 #endif
 158 #ifdef CONFIG_AUDITSYSCALL
 159         PROC_TID_LOGINUID,
 160 #endif
 161         PROC_TID_OOM_SCORE,
 162         PROC_TID_OOM_ADJUST,
 163
 164         /* Add new entries before this */
 165         PROC_TID_FD_DIR = 0x8000,       /* 0x8000-0xffff */
 166 };
 167
 168 struct pid_entry {
 169         int type;
 170         int len;
 171         char *name;
 172         mode_t mode;
 173 };
 174
 175 #define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}
 176
 177 static struct pid_entry tgid_base_stuff[] = {
 178         E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
 179         E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
 180         E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
 181         E(PROC_TGID_AUXV,      "auxv",    S_IFREG|S_IRUSR),
 182         E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
 183         E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
 184         E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
 185         E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
 186         E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
 187 #ifdef CONFIG_NUMA
 188         E(PROC_TGID_NUMA_MAPS, "numa_maps", S_IFREG|S_IRUGO),
 189 #endif
 190         E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 191 #ifdef CONFIG_SECCOMP
 192         E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
 193 #endif
 194         E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
 195         E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
 196         E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
 197         E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
 198         E(PROC_TGID_SMAPS,     "smaps",   S_IFREG|S_IRUGO),
 199 #ifdef CONFIG_SECURITY
 200         E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
 201 #endif
 202 #ifdef CONFIG_KALLSYMS
 203         E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
 204 #endif
 205 #ifdef CONFIG_SCHEDSTATS
 206         E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
 207 #endif
 208 #ifdef CONFIG_CPUSETS
 209         E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
 210 #endif
 211         E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
 212         E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
 213 #ifdef CONFIG_AUDITSYSCALL
 214         E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 215 #endif
 216         {0,0,NULL,0}
 217 };
 218 static struct pid_entry tid_base_stuff[] = {
 219         E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
 220         E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
 221         E(PROC_TID_AUXV,       "auxv",    S_IFREG|S_IRUSR),
 222         E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
 223         E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
 224         E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
 225         E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
 226         E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
 227 #ifdef CONFIG_NUMA
 228         E(PROC_TID_NUMA_MAPS,  "numa_maps",    S_IFREG|S_IRUGO),
 229 #endif
 230         E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 231 #ifdef CONFIG_SECCOMP
 232         E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
 233 #endif
 234         E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
 235         E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
 236         E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
 237         E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
 238         E(PROC_TID_SMAPS,      "smaps",   S_IFREG|S_IRUGO),
 239 #ifdef CONFIG_SECURITY
 240         E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
 241 #endif
 242 #ifdef CONFIG_KALLSYMS
 243         E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
 244 #endif
 245 #ifdef CONFIG_SCHEDSTATS
 246         E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
 247 #endif
 248 #ifdef CONFIG_CPUSETS
 249         E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
 250 #endif
 251         E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
 252         E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
 253 #ifdef CONFIG_AUDITSYSCALL
 254         E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 255 #endif
 256         {0,0,NULL,0}
 257 };
 258
 259 #ifdef CONFIG_SECURITY
 260 static struct pid_entry tgid_attr_stuff[] = {
 261         E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
 262         E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
 263         E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
 264         E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 265         {0,0,NULL,0}
 266 };
 267 static struct pid_entry tid_attr_stuff[] = {
 268         E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
 269         E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
 270         E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
 271         E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 272         {0,0,NULL,0}
 273 };
 274 #endif
 275
 276 #undef E
 277
 278 static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 279 {
 280         struct task_struct *task = proc_task(inode);
 281         struct files_struct *files;
 282         struct file *file;
 283         int fd = proc_type(inode) - PROC_TID_FD_DIR;
 284
 285         files = get_files_struct(task);
 286         if (files) {
 287                 rcu_read_lock();
 288                 file = fcheck_files(files, fd);
 289                 if (file) {
 290                         *mnt = mntget(file->f_vfsmnt);
 291                         *dentry = dget(file->f_dentry);
 292                         rcu_read_unlock();
 293                         put_files_struct(files);
 294                         return 0;
 295                 }
 296                 rcu_read_unlock();
 297                 put_files_struct(files);
 298         }
 299         return -ENOENT;
 300 }
 301
 302 static struct fs_struct *get_fs_struct(struct task_struct *task)
 303 {
 304         struct fs_struct *fs;
 305         task_lock(task);
 306         fs = task->fs;
 307         if(fs)
 308                 atomic_inc(&fs->count);
 309         task_unlock(task);
 310         return fs;
 311 }
 312
 313 static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 314 {
 315         struct fs_struct *fs = get_fs_struct(proc_task(inode));
 316         int result = -ENOENT;
 317         if (fs) {
 318                 read_lock(&fs->lock);
 319                 *mnt = mntget(fs->pwdmnt);
 320                 *dentry = dget(fs->pwd);
 321                 read_unlock(&fs->lock);
 322                 result = 0;
 323                 put_fs_struct(fs);
 324         }
 325         return result;
 326 }
 327
 328 static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 329 {
 330         struct fs_struct *fs = get_fs_struct(proc_task(inode));
 331         int result = -ENOENT;
 332         if (fs) {
 333                 read_lock(&fs->lock);
 334                 *mnt = mntget(fs->rootmnt);
 335                 *dentry = dget(fs->root);
 336                 read_unlock(&fs->lock);
 337                 result = 0;
 338                 put_fs_struct(fs);
 339         }
 340         return result;
 341 }
 342
 343
 344 /* Same as proc_root_link, but this addionally tries to get fs from other
 345  * threads in the group */
 346 static int proc_task_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 347 {
 348         struct fs_struct *fs;
 349         int result = -ENOENT;
 350         struct task_struct *leader = proc_task(inode);
 351
 352         task_lock(leader);
 353         fs = leader->fs;
 354         if (fs) {
 355                 atomic_inc(&fs->count);
 356                 task_unlock(leader);
 357         } else {
 358                 /* Try to get fs from other threads */
 359                 task_unlock(leader);
 360                 struct task_struct *task = leader;
 361                 read_lock(&tasklist_lock);
 362                 if (pid_alive(task)) {
 363                         while ((task = next_thread(task)) != leader) {
 364                                 task_lock(task);
 365                                 fs = task->fs;
 366                                 if (fs) {
 367                                         atomic_inc(&fs->count);
 368                                         task_unlock(task);
 369                                         break;
 370                                 }
 371                                 task_unlock(task);
 372                         }
 373                 }
 374                 read_unlock(&tasklist_lock);
 375         }
 376
 377         if (fs) {
 378                 read_lock(&fs->lock);
 379                 *mnt = mntget(fs->rootmnt);
 380                 *dentry = dget(fs->root);
 381                 read_unlock(&fs->lock);
 382                 result = 0;
 383                 put_fs_struct(fs);
 384         }
 385         return result;
 386 }
 387
 388
 389 #define MAY_PTRACE(task) \
 390         (task == current || \
 391         (task->parent == current && \
 392         (task->ptrace & PT_PTRACED) && \
 393          (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
 394          security_ptrace(current,task) == 0))
 395
 396 static int proc_pid_environ(struct task_struct *task, char * buffer)
 397 {
 398         int res = 0;
 399         struct mm_struct *mm = get_task_mm(task);
 400         if (mm) {
 401                 unsigned int len = mm->env_end - mm->env_start;
 402                 if (len > PAGE_SIZE)
 403                         len = PAGE_SIZE;
 404                 res = access_process_vm(task, mm->env_start, buffer, len, 0);
 405                 if (!ptrace_may_attach(task))
 406                         res = -ESRCH;
 407                 mmput(mm);
 408         }
 409         return res;
 410 }
 411
 412 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 413 {
 414         int res = 0;
 415         unsigned int len;
 416         struct mm_struct *mm = get_task_mm(task);
 417         if (!mm)
 418                 goto out;
 419         if (!mm->arg_end)
 420                 goto out_mm;    /* Shh! No looking before we're done */
 421
 422         len = mm->arg_end - mm->arg_start;
 423
 424         if (len > PAGE_SIZE)
 425                 len = PAGE_SIZE;
 426
 427         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 428
 429         // If the nul at the end of args has been overwritten, then
 430         // assume application is using setproctitle(3).
 431         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 432                 len = strnlen(buffer, res);
 433                 if (len < res) {
 434                     res = len;
 435                 } else {
 436                         len = mm->env_end - mm->env_start;
 437                         if (len > PAGE_SIZE - res)
 438                                 len = PAGE_SIZE - res;
 439                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 440                         res = strnlen(buffer, res);
 441                 }
 442         }
 443 out_mm:
 444         mmput(mm);
 445 out:
 446         return res;
 447 }
 448
 449 static int proc_pid_auxv(struct task_struct *task, char *buffer)
 450 {
 451         int res = 0;
 452         struct mm_struct *mm = get_task_mm(task);
 453         if (mm) {
 454                 unsigned int nwords = 0;
 455                 do
 456                         nwords += 2;
 457                 while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 458                 res = nwords * sizeof(mm->saved_auxv[0]);
 459                 if (res > PAGE_SIZE)
 460                         res = PAGE_SIZE;
 461                 memcpy(buffer, mm->saved_auxv, res);
 462                 mmput(mm);
 463         }
 464         return res;
 465 }
 466
 467
 468 #ifdef CONFIG_KALLSYMS
 469 /*
 470  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 471  * Returns the resolved symbol.  If that fails, simply return the address.
 472  */
 473 static int proc_pid_wchan(struct task_struct *task, char *buffer)
 474 {
 475         char *modname;
 476         const char *sym_name;
 477         unsigned long wchan, size, offset;
 478         char namebuf[KSYM_NAME_LEN+1];
 479
 480         wchan = get_wchan(task);
 481
 482         sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
 483         if (sym_name)
 484                 return sprintf(buffer, "%s", sym_name);
 485         return sprintf(buffer, "%lu", wchan);
 486 }
 487 #endif /* CONFIG_KALLSYMS */
 488
 489 #ifdef CONFIG_SCHEDSTATS
 490 /*
 491  * Provides /proc/PID/schedstat
 492  */
 493 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 494 {
 495         return sprintf(buffer, "%lu %lu %lu\n",
 496                         task->sched_info.cpu_time,
 497                         task->sched_info.run_delay,
 498                         task->sched_info.pcnt);
 499 }
 500 #endif
 501
 502 /* The badness from the OOM killer */
 503 unsigned long badness(struct task_struct *p, unsigned long uptime);
 504 static int proc_oom_score(struct task_struct *task, char *buffer)
 505 {
 506         unsigned long points;
 507         struct timespec uptime;
 508
 509         do_posix_clock_monotonic_gettime(&uptime);
 510         points = badness(task, uptime.tv_sec);
 511         return sprintf(buffer, "%lu\n", points);
 512 }
 513
 514 /************************************************************************/
 515 /*                       Here the fs part begins                        */
 516 /************************************************************************/
 517
 518 /* permission checks */
 519
 520 /* If the process being read is separated by chroot from the reading process,
 521  * don't let the reader access the threads.
 522  */
 523 static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt)
 524 {
 525         struct dentry *de, *base;
 526         struct vfsmount *our_vfsmnt, *mnt;
 527         int res = 0;
 528         read_lock(&current->fs->lock);
 529         our_vfsmnt = mntget(current->fs->rootmnt);
 530         base = dget(current->fs->root);
 531         read_unlock(&current->fs->lock);
 532
 533         spin_lock(&vfsmount_lock);
 534         de = root;
 535         mnt = vfsmnt;
 536
 537         while (vfsmnt != our_vfsmnt) {
 538                 if (vfsmnt == vfsmnt->mnt_parent)
 539                         goto out;
 540                 de = vfsmnt->mnt_mountpoint;
 541                 vfsmnt = vfsmnt->mnt_parent;
 542         }
 543
 544         if (!is_subdir(de, base))
 545                 goto out;
 546         spin_unlock(&vfsmount_lock);
 547
 548 exit:
 549         dput(base);
 550         mntput(our_vfsmnt);
 551         dput(root);
 552         mntput(mnt);
 553         return res;
 554 out:
 555         spin_unlock(&vfsmount_lock);
 556         res = -EACCES;
 557         goto exit;
 558 }
 559
 560 static int proc_check_root(struct inode *inode)
 561 {
 562         struct dentry *root;
 563         struct vfsmount *vfsmnt;
 564
 565         if (proc_root_link(inode, &root, &vfsmnt)) /* Ewww... */
 566                 return -ENOENT;
 567         return proc_check_chroot(root, vfsmnt);
 568 }
 569
 570 static int proc_permission(struct inode *inode, int mask, struct nameidata *nd)
 571 {
 572         if (generic_permission(inode, mask, NULL) != 0)
 573                 return -EACCES;
 574         return proc_check_root(inode);
 575 }
 576
 577 static int proc_task_permission(struct inode *inode, int mask, struct nameidata *nd)
 578 {
 579         struct dentry *root;
 580         struct vfsmount *vfsmnt;
 581
 582         if (generic_permission(inode, mask, NULL) != 0)
 583                 return -EACCES;
 584
 585         if (proc_task_root_link(inode, &root, &vfsmnt))
 586                 return -ENOENT;
 587
 588         return proc_check_chroot(root, vfsmnt);
 589 }
 590
 591 extern struct seq_operations proc_pid_maps_op;
 592 static int maps_open(struct inode *inode, struct file *file)
 593 {
 594         struct task_struct *task = proc_task(inode);
 595         int ret = seq_open(file, &proc_pid_maps_op);
 596         if (!ret) {
 597                 struct seq_file *m = file->private_data;
 598                 m->private = task;
 599         }
 600         return ret;
 601 }
 602
 603 static struct file_operations proc_maps_operations = {
 604         .open           = maps_open,
 605         .read           = seq_read,
 606         .llseek         = seq_lseek,
 607         .release        = seq_release,
 608 };
 609
 610 #ifdef CONFIG_NUMA
 611 extern struct seq_operations proc_pid_numa_maps_op;
 612 static int numa_maps_open(struct inode *inode, struct file *file)
 613 {
 614         struct task_struct *task = proc_task(inode);
 615         int ret = seq_open(file, &proc_pid_numa_maps_op);
 616         if (!ret) {
 617                 struct seq_file *m = file->private_data;
 618                 m->private = task;
 619         }
 620         return ret;
 621 }
 622
 623 static struct file_operations proc_numa_maps_operations = {
 624         .open           = numa_maps_open,
 625         .read           = seq_read,
 626         .llseek         = seq_lseek,
 627         .release        = seq_release,
 628 };
 629 #endif
 630
 631 extern struct seq_operations proc_pid_smaps_op;
 632 static int smaps_open(struct inode *inode, struct file *file)
 633 {
 634         struct task_struct *task = proc_task(inode);
 635         int ret = seq_open(file, &proc_pid_smaps_op);
 636         if (!ret) {
 637                 struct seq_file *m = file->private_data;
 638                 m->private = task;
 639         }
 640         return ret;
 641 }
 642
 643 static struct file_operations proc_smaps_operations = {
 644         .open           = smaps_open,
 645         .read           = seq_read,
 646         .llseek         = seq_lseek,
 647         .release        = seq_release,
 648 };
 649
 650 extern struct seq_operations mounts_op;
 651 static int mounts_open(struct inode *inode, struct file *file)
 652 {
 653         struct task_struct *task = proc_task(inode);
 654         int ret = seq_open(file, &mounts_op);
 655
 656         if (!ret) {
 657                 struct seq_file *m = file->private_data;
 658                 struct namespace *namespace;
 659                 task_lock(task);
 660                 namespace = task->namespace;
 661                 if (namespace)
 662                         get_namespace(namespace);
 663                 task_unlock(task);
 664
 665                 if (namespace)
 666                         m->private = namespace;
 667                 else {
 668                         seq_release(inode, file);
 669                         ret = -EINVAL;
 670                 }
 671         }
 672         return ret;
 673 }
 674
 675 static int mounts_release(struct inode *inode, struct file *file)
 676 {
 677         struct seq_file *m = file->private_data;
 678         struct namespace *namespace = m->private;
 679         put_namespace(namespace);
 680         return seq_release(inode, file);
 681 }
 682
 683 static struct file_operations proc_mounts_operations = {
 684         .open           = mounts_open,
 685         .read           = seq_read,
 686         .llseek         = seq_lseek,
 687         .release        = mounts_release,
 688 };
 689
 690 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 691
 692 static ssize_t proc_info_read(struct file * file, char __user * buf,
 693                           size_t count, loff_t *ppos)
 694 {
 695         struct inode * inode = file->f_dentry->d_inode;
 696         unsigned long page;
 697         ssize_t length;
 698         struct task_struct *task = proc_task(inode);
 699
 700         if (count > PROC_BLOCK_SIZE)
 701                 count = PROC_BLOCK_SIZE;
 702         if (!(page = __get_free_page(GFP_KERNEL)))
 703                 return -ENOMEM;
 704
 705         length = PROC_I(inode)->op.proc_read(task, (char*)page);
 706
 707         if (length >= 0)
 708                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 709         free_page(page);
 710         return length;
 711 }
 712
 713 static struct file_operations proc_info_file_operations = {
 714         .read           = proc_info_read,
 715 };
 716
 717 static int mem_open(struct inode* inode, struct file* file)
 718 {
 719         file->private_data = (void*)((long)current->self_exec_id);
 720         return 0;
 721 }
 722
 723 static ssize_t mem_read(struct file * file, char __user * buf,
 724                         size_t count, loff_t *ppos)
 725 {
 726         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 727         char *page;
 728         unsigned long src = *ppos;
 729         int ret = -ESRCH;
 730         struct mm_struct *mm;
 731
 732         if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
 733                 goto out;
 734
 735         ret = -ENOMEM;
 736         page = (char *)__get_free_page(GFP_USER);
 737         if (!page)
 738                 goto out;
 739
 740         ret = 0;
 741
 742         mm = get_task_mm(task);
 743         if (!mm)
 744                 goto out_free;
 745
 746         ret = -EIO;
 747
 748         if (file->private_data != (void*)((long)current->self_exec_id))
 749                 goto out_put;
 750
 751         ret = 0;
 752
 753         while (count > 0) {
 754                 int this_len, retval;
 755
 756                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 757                 retval = access_process_vm(task, src, page, this_len, 0);
 758                 if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
 759                         if (!ret)
 760                                 ret = -EIO;
 761                         break;
 762                 }
 763
 764                 if (copy_to_user(buf, page, retval)) {
 765                         ret = -EFAULT;
 766                         break;
 767                 }
 768
 769                 ret += retval;
 770                 src += retval;
 771                 buf += retval;
 772                 count -= retval;
 773         }
 774         *ppos = src;
 775
 776 out_put:
 777         mmput(mm);
 778 out_free:
 779         free_page((unsigned long) page);
 780 out:
 781         return ret;
 782 }
 783
 784 #define mem_write NULL
 785
 786 #ifndef mem_write
 787 /* This is a security hazard */
 788 static ssize_t mem_write(struct file * file, const char * buf,
 789                          size_t count, loff_t *ppos)
 790 {
 791         int copied = 0;
 792         char *page;
 793         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 794         unsigned long dst = *ppos;
 795
 796         if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
 797                 return -ESRCH;
 798
 799         page = (char *)__get_free_page(GFP_USER);
 800         if (!page)
 801                 return -ENOMEM;
 802
 803         while (count > 0) {
 804                 int this_len, retval;
 805
 806                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 807                 if (copy_from_user(page, buf, this_len)) {
 808                         copied = -EFAULT;
 809                         break;
 810                 }
 811                 retval = access_process_vm(task, dst, page, this_len, 1);
 812                 if (!retval) {
 813                         if (!copied)
 814                                 copied = -EIO;
 815                         break;
 816                 }
 817                 copied += retval;
 818                 buf += retval;
 819                 dst += retval;
 820                 count -= retval;
 821         }
 822         *ppos = dst;
 823         free_page((unsigned long) page);
 824         return copied;
 825 }
 826 #endif
 827
 828 static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
 829 {
 830         switch (orig) {
 831         case 0:
 832                 file->f_pos = offset;
 833                 break;
 834         case 1:
 835                 file->f_pos += offset;
 836                 break;
 837         default:
 838                 return -EINVAL;
 839         }
 840         force_successful_syscall_return();
 841         return file->f_pos;
 842 }
 843
 844 static struct file_operations proc_mem_operations = {
 845         .llseek         = mem_lseek,
 846         .read           = mem_read,
 847         .write          = mem_write,
 848         .open           = mem_open,
 849 };
 850
 851 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
 852                                 size_t count, loff_t *ppos)
 853 {
 854         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 855         char buffer[8];
 856         size_t len;
 857         int oom_adjust = task->oomkilladj;
 858         loff_t __ppos = *ppos;
 859
 860         len = sprintf(buffer, "%i\n", oom_adjust);
 861         if (__ppos >= len)
 862                 return 0;
 863         if (count > len-__ppos)
 864                 count = len-__ppos;
 865         if (copy_to_user(buf, buffer + __ppos, count))
 866                 return -EFAULT;
 867         *ppos = __ppos + count;
 868         return count;
 869 }
 870
 871 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 872                                 size_t count, loff_t *ppos)
 873 {
 874         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 875         char buffer[8], *end;
 876         int oom_adjust;
 877
 878         if (!capable(CAP_SYS_RESOURCE))
 879                 return -EPERM;
 880         memset(buffer, 0, 8);
 881         if (count > 6)
 882                 count = 6;
 883         if (copy_from_user(buffer, buf, count))
 884                 return -EFAULT;
 885         oom_adjust = simple_strtol(buffer, &end, 0);
 886         if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
 887                 return -EINVAL;
 888         if (*end == '\n')
 889                 end++;
 890         task->oomkilladj = oom_adjust;
 891         if (end - buffer == 0)
 892                 return -EIO;
 893         return end - buffer;
 894 }
 895
 896 static struct file_operations proc_oom_adjust_operations = {
 897         .read           = oom_adjust_read,
 898         .write          = oom_adjust_write,
 899 };
 900
 901 static struct inode_operations proc_mem_inode_operations = {
 902         .permission     = proc_permission,
 903 };
 904
 905 #ifdef CONFIG_AUDITSYSCALL
 906 #define TMPBUFLEN 21
 907 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
 908                                   size_t count, loff_t *ppos)
 909 {
 910         struct inode * inode = file->f_dentry->d_inode;
 911         struct task_struct *task = proc_task(inode);
 912         ssize_t length;
 913         char tmpbuf[TMPBUFLEN];
 914
 915         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
 916                                 audit_get_loginuid(task->audit_context));
 917         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 918 }
 919
 920 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 921                                    size_t count, loff_t *ppos)
 922 {
 923         struct inode * inode = file->f_dentry->d_inode;
 924         char *page, *tmp;
 925         ssize_t length;
 926         struct task_struct *task = proc_task(inode);
 927         uid_t loginuid;
 928
 929         if (!capable(CAP_AUDIT_CONTROL))
 930                 return -EPERM;
 931
 932         if (current != task)
 933                 return -EPERM;
 934
 935         if (count > PAGE_SIZE)
 936                 count = PAGE_SIZE;
 937
 938         if (*ppos != 0) {
 939                 /* No partial writes. */
 940                 return -EINVAL;
 941         }
 942         page = (char*)__get_free_page(GFP_USER);
 943         if (!page)
 944                 return -ENOMEM;
 945         length = -EFAULT;
 946         if (copy_from_user(page, buf, count))
 947                 goto out_free_page;
 948
 949         loginuid = simple_strtoul(page, &tmp, 10);
 950         if (tmp == page) {
 951                 length = -EINVAL;
 952                 goto out_free_page;
 953
 954         }
 955         length = audit_set_loginuid(task, loginuid);
 956         if (likely(length == 0))
 957                 length = count;
 958
 959 out_free_page:
 960         free_page((unsigned long) page);
 961         return length;
 962 }
 963
 964 static struct file_operations proc_loginuid_operations = {
 965         .read           = proc_loginuid_read,
 966         .write          = proc_loginuid_write,
 967 };
 968 #endif
 969
 970 #ifdef CONFIG_SECCOMP
 971 static ssize_t seccomp_read(struct file *file, char __user *buf,
 972                             size_t count, loff_t *ppos)
 973 {
 974         struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
 975         char __buf[20];
 976         loff_t __ppos = *ppos;
 977         size_t len;
 978
 979         /* no need to print the trailing zero, so use only len */
 980         len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
 981         if (__ppos >= len)
 982                 return 0;
 983         if (count > len - __ppos)
 984                 count = len - __ppos;
 985         if (copy_to_user(buf, __buf + __ppos, count))
 986                 return -EFAULT;
 987         *ppos = __ppos + count;
 988         return count;
 989 }
 990
 991 static ssize_t seccomp_write(struct file *file, const char __user *buf,
 992                              size_t count, loff_t *ppos)
 993 {
 994         struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
 995         char __buf[20], *end;
 996         unsigned int seccomp_mode;
 997
 998         /* can set it only once to be even more secure */
 999         if (unlikely(tsk->seccomp.mode))
1000                 return -EPERM;
1001
1002         memset(__buf, 0, sizeof(__buf));
1003         count = min(count, sizeof(__buf) - 1);
1004         if (copy_from_user(__buf, buf, count))
1005                 return -EFAULT;
1006         seccomp_mode = simple_strtoul(__buf, &end, 0);
1007         if (*end == '\n')
1008                 end++;
1009         if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
1010                 tsk->seccomp.mode = seccomp_mode;
1011                 set_tsk_thread_flag(tsk, TIF_SECCOMP);
1012         } else
1013                 return -EINVAL;
1014         if (unlikely(!(end - __buf)))
1015                 return -EIO;
1016         return end - __buf;
1017 }
1018
1019 static struct file_operations proc_seccomp_operations = {
1020         .read           = seccomp_read,
1021         .write          = seccomp_write,
1022 };
1023 #endif /* CONFIG_SECCOMP */
1024
1025 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1026 {
1027         struct inode *inode = dentry->d_inode;
1028         int error = -EACCES;
1029
1030         /* We don't need a base pointer in the /proc filesystem */
1031         path_release(nd);
1032
1033         if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
1034                 goto out;
1035         error = proc_check_root(inode);
1036         if (error)
1037                 goto out;
1038
1039         error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
1040         nd->last_type = LAST_BIND;
1041 out:
1042         return ERR_PTR(error);
1043 }
1044
1045 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
1046                             char __user *buffer, int buflen)
1047 {
1048         struct inode * inode;
1049         char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
1050         int len;
1051
1052         if (!tmp)
1053                 return -ENOMEM;
1054
1055         inode = dentry->d_inode;
1056         path = d_path(dentry, mnt, tmp, PAGE_SIZE);
1057         len = PTR_ERR(path);
1058         if (IS_ERR(path))
1059                 goto out;
1060         len = tmp + PAGE_SIZE - 1 - path;
1061
1062         if (len > buflen)
1063                 len = buflen;
1064         if (copy_to_user(buffer, path, len))
1065                 len = -EFAULT;
1066  out:
1067         free_page((unsigned long)tmp);
1068         return len;
1069 }
1070
1071 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1072 {
1073         int error = -EACCES;
1074         struct inode *inode = dentry->d_inode;
1075         struct dentry *de;
1076         struct vfsmount *mnt = NULL;
1077
1078         lock_kernel();
1079
1080         if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
1081                 goto out;
1082         error = proc_check_root(inode);
1083         if (error)
1084                 goto out;
1085
1086         error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
1087         if (error)
1088                 goto out;
1089
1090         error = do_proc_readlink(de, mnt, buffer, buflen);
1091         dput(de);
1092         mntput(mnt);
1093 out:
1094         unlock_kernel();
1095         return error;
1096 }
1097
1098 static struct inode_operations proc_pid_link_inode_operations = {
1099         .readlink       = proc_pid_readlink,
1100         .follow_link    = proc_pid_follow_link
1101 };
1102
1103 #define NUMBUF 10
1104
1105 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
1106 {
1107         struct inode *inode = filp->f_dentry->d_inode;
1108         struct task_struct *p = proc_task(inode);
1109         unsigned int fd, tid, ino;
1110         int retval;
1111         char buf[NUMBUF];
1112         struct files_struct * files;
1113         struct fdtable *fdt;
1114
1115         retval = -ENOENT;
1116         if (!pid_alive(p))
1117                 goto out;
1118         retval = 0;
1119         tid = p->pid;
1120
1121         fd = filp->f_pos;
1122         switch (fd) {
1123                 case 0:
1124                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1125                                 goto out;
1126                         filp->f_pos++;
1127                 case 1:
1128                         ino = fake_ino(tid, PROC_TID_INO);
1129                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1130                                 goto out;
1131                         filp->f_pos++;
1132                 default:
1133                         files = get_files_struct(p);
1134                         if (!files)
1135                                 goto out;
1136                         rcu_read_lock();
1137                         fdt = files_fdtable(files);
1138                         for (fd = filp->f_pos-2;
1139                              fd < fdt->max_fds;
1140                              fd++, filp->f_pos++) {
1141                                 unsigned int i,j;
1142
1143                                 if (!fcheck_files(files, fd))
1144                                         continue;
1145                                 rcu_read_unlock();
1146
1147                                 j = NUMBUF;
1148                                 i = fd;
1149                                 do {
1150                                         j--;
1151                                         buf[j] = '0' + (i % 10);
1152                                         i /= 10;
1153                                 } while (i);
1154
1155                                 ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
1156                                 if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
1157                                         rcu_read_lock();
1158                                         break;
1159                                 }
1160                                 rcu_read_lock();
1161                         }
1162                         rcu_read_unlock();
1163                         put_files_struct(files);
1164         }
1165 out:
1166         return retval;
1167 }
1168
1169 static int proc_pident_readdir(struct file *filp,
1170                 void *dirent, filldir_t filldir,
1171                 struct pid_entry *ents, unsigned int nents)
1172 {
1173         int i;
1174         int pid;
1175         struct dentry *dentry = filp->f_dentry;
1176         struct inode *inode = dentry->d_inode;
1177         struct pid_entry *p;
1178         ino_t ino;
1179         int ret;
1180
1181         ret = -ENOENT;
1182         if (!pid_alive(proc_task(inode)))
1183                 goto out;
1184
1185         ret = 0;
1186         pid = proc_task(inode)->pid;
1187         i = filp->f_pos;
1188         switch (i) {
1189         case 0:
1190                 ino = inode->i_ino;
1191                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1192                         goto out;
1193                 i++;
1194                 filp->f_pos++;
1195                 /* fall through */
1196         case 1:
1197                 ino = parent_ino(dentry);
1198                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1199                         goto out;
1200                 i++;
1201                 filp->f_pos++;
1202                 /* fall through */
1203         default:
1204                 i -= 2;
1205                 if (i >= nents) {
1206                         ret = 1;
1207                         goto out;
1208                 }
1209                 p = ents + i;
1210                 while (p->name) {
1211                         if (filldir(dirent, p->name, p->len, filp->f_pos,
1212                                     fake_ino(pid, p->type), p->mode >> 12) < 0)
1213                                 goto out;
1214                         filp->f_pos++;
1215                         p++;
1216                 }
1217         }
1218
1219         ret = 1;
1220 out:
1221         return ret;
1222 }
1223
1224 static int proc_tgid_base_readdir(struct file * filp,
1225                              void * dirent, filldir_t filldir)
1226 {
1227         return proc_pident_readdir(filp,dirent,filldir,
1228                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
1229 }
1230
1231 static int proc_tid_base_readdir(struct file * filp,
1232                              void * dirent, filldir_t filldir)
1233 {
1234         return proc_pident_readdir(filp,dirent,filldir,
1235                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
1236 }
1237
1238 /* building an inode */
1239
1240 static int task_dumpable(struct task_struct *task)
1241 {
1242         int dumpable = 0;
1243         struct mm_struct *mm;
1244
1245         task_lock(task);
1246         mm = task->mm;
1247         if (mm)
1248                 dumpable = mm->dumpable;
1249         task_unlock(task);
1250         if(dumpable == 1)
1251                 return 1;
1252         return 0;
1253 }
1254
1255
1256 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
1257 {
1258         struct inode * inode;
1259         struct proc_inode *ei;
1260
1261         /* We need a new inode */
1262
1263         inode = new_inode(sb);
1264         if (!inode)
1265                 goto out;
1266
1267         /* Common stuff */
1268         ei = PROC_I(inode);
1269         ei->task = NULL;
1270         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1271         inode->i_ino = fake_ino(task->pid, ino);
1272
1273         if (!pid_alive(task))
1274                 goto out_unlock;
1275
1276         /*
1277          * grab the reference to task.
1278          */
1279         get_task_struct(task);
1280         ei->task = task;
1281         ei->type = ino;
1282         inode->i_uid = 0;
1283         inode->i_gid = 0;
1284         if (ino == PROC_TGID_INO || ino == PROC_TID_INO || task_dumpable(task)) {
1285                 inode->i_uid = task->euid;
1286                 inode->i_gid = task->egid;
1287         }
1288         security_task_to_inode(task, inode);
1289
1290 out:
1291         return inode;
1292
1293 out_unlock:
1294         ei->pde = NULL;
1295         iput(inode);
1296         return NULL;
1297 }
1298
1299 /* dentry stuff */
1300
1301 /*
1302  *      Exceptional case: normally we are not allowed to unhash a busy
1303  * directory. In this case, however, we can do it - no aliasing problems
1304  * due to the way we treat inodes.
1305  *
1306  * Rewrite the inode's ownerships here because the owning task may have
1307  * performed a setuid(), etc.
1308  */
1309 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1310 {
1311         struct inode *inode = dentry->d_inode;
1312         struct task_struct *task = proc_task(inode);
1313         if (pid_alive(task)) {
1314                 if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || task_dumpable(task)) {
1315                         inode->i_uid = task->euid;
1316                         inode->i_gid = task->egid;
1317                 } else {
1318                         inode->i_uid = 0;
1319                         inode->i_gid = 0;
1320                 }
1321                 security_task_to_inode(task, inode);
1322                 return 1;
1323         }
1324         d_drop(dentry);
1325         return 0;
1326 }
1327
1328 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1329 {
1330         struct inode *inode = dentry->d_inode;
1331         struct task_struct *task = proc_task(inode);
1332         int fd = proc_type(inode) - PROC_TID_FD_DIR;
1333         struct files_struct *files;
1334
1335         files = get_files_struct(task);
1336         if (files) {
1337                 rcu_read_lock();
1338                 if (fcheck_files(files, fd)) {
1339                         rcu_read_unlock();
1340                         put_files_struct(files);
1341                         if (task_dumpable(task)) {
1342                                 inode->i_uid = task->euid;
1343                                 inode->i_gid = task->egid;
1344                         } else {
1345                                 inode->i_uid = 0;
1346                                 inode->i_gid = 0;
1347                         }
1348                         security_task_to_inode(task, inode);
1349                         return 1;
1350                 }
1351                 rcu_read_unlock();
1352                 put_files_struct(files);
1353         }
1354         d_drop(dentry);
1355         return 0;
1356 }
1357
1358 static void pid_base_iput(struct dentry *dentry, struct inode *inode)
1359 {
1360         struct task_struct *task = proc_task(inode);
1361         spin_lock(&task->proc_lock);
1362         if (task->proc_dentry == dentry)
1363                 task->proc_dentry = NULL;
1364         spin_unlock(&task->proc_lock);
1365         iput(inode);
1366 }
1367
1368 static int pid_delete_dentry(struct dentry * dentry)
1369 {
1370         /* Is the task we represent dead?
1371          * If so, then don't put the dentry on the lru list,
1372          * kill it immediately.
1373          */
1374         return !pid_alive(proc_task(dentry->d_inode));
1375 }
1376
1377 static struct dentry_operations tid_fd_dentry_operations =
1378 {
1379         .d_revalidate   = tid_fd_revalidate,
1380         .d_delete       = pid_delete_dentry,
1381 };
1382
1383 static struct dentry_operations pid_dentry_operations =
1384 {
1385         .d_revalidate   = pid_revalidate,
1386         .d_delete       = pid_delete_dentry,
1387 };
1388
1389 static struct dentry_operations pid_base_dentry_operations =
1390 {
1391         .d_revalidate   = pid_revalidate,
1392         .d_iput         = pid_base_iput,
1393         .d_delete       = pid_delete_dentry,
1394 };
1395
1396 /* Lookups */
1397
1398 static unsigned name_to_int(struct dentry *dentry)
1399 {
1400         const char *name = dentry->d_name.name;
1401         int len = dentry->d_name.len;
1402         unsigned n = 0;
1403
1404         if (len > 1 && *name == '0')
1405                 goto out;
1406         while (len-- > 0) {
1407                 unsigned c = *name++ - '0';
1408                 if (c > 9)
1409                         goto out;
1410                 if (n >= (~0U-9)/10)
1411                         goto out;
1412                 n *= 10;
1413                 n += c;
1414         }
1415         return n;
1416 out:
1417         return ~0U;
1418 }
1419
1420 /* SMP-safe */
1421 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
1422 {
1423         struct task_struct *task = proc_task(dir);
1424         unsigned fd = name_to_int(dentry);
1425         struct file * file;
1426         struct files_struct * files;
1427         struct inode *inode;
1428         struct proc_inode *ei;
1429
1430         if (fd == ~0U)
1431                 goto out;
1432         if (!pid_alive(task))
1433                 goto out;
1434
1435         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
1436         if (!inode)
1437                 goto out;
1438         ei = PROC_I(inode);
1439         files = get_files_struct(task);
1440         if (!files)
1441                 goto out_unlock;
1442         inode->i_mode = S_IFLNK;
1443         rcu_read_lock();
1444         file = fcheck_files(files, fd);
1445         if (!file)
1446                 goto out_unlock2;
1447         if (file->f_mode & 1)
1448                 inode->i_mode |= S_IRUSR | S_IXUSR;
1449         if (file->f_mode & 2)
1450                 inode->i_mode |= S_IWUSR | S_IXUSR;
1451         rcu_read_unlock();
1452         put_files_struct(files);
1453         inode->i_op = &proc_pid_link_inode_operations;
1454         inode->i_size = 64;
1455         ei->op.proc_get_link = proc_fd_link;
1456         dentry->d_op = &tid_fd_dentry_operations;
1457         d_add(dentry, inode);
1458         return NULL;
1459
1460 out_unlock2:
1461         rcu_read_unlock();
1462         put_files_struct(files);
1463 out_unlock:
1464         iput(inode);
1465 out:
1466         return ERR_PTR(-ENOENT);
1467 }
1468
1469 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
1470 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
1471
1472 static struct file_operations proc_fd_operations = {
1473         .read           = generic_read_dir,
1474         .readdir        = proc_readfd,
1475 };
1476
1477 static struct file_operations proc_task_operations = {
1478         .read           = generic_read_dir,
1479         .readdir        = proc_task_readdir,
1480 };
1481
1482 /*
1483  * proc directories can do almost nothing..
1484  */
1485 static struct inode_operations proc_fd_inode_operations = {
1486         .lookup         = proc_lookupfd,
1487         .permission     = proc_permission,
1488 };
1489
1490 static struct inode_operations proc_task_inode_operations = {
1491         .lookup         = proc_task_lookup,
1492         .permission     = proc_task_permission,
1493 };
1494
1495 #ifdef CONFIG_SECURITY
1496 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
1497                                   size_t count, loff_t *ppos)
1498 {
1499         struct inode * inode = file->f_dentry->d_inode;
1500         unsigned long page;
1501         ssize_t length;
1502         struct task_struct *task = proc_task(inode);
1503
1504         if (count > PAGE_SIZE)
1505                 count = PAGE_SIZE;
1506         if (!(page = __get_free_page(GFP_KERNEL)))
1507                 return -ENOMEM;
1508
1509         length = security_getprocattr(task,
1510                                       (char*)file->f_dentry->d_name.name,
1511                                       (void*)page, count);
1512         if (length >= 0)
1513                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
1514         free_page(page);
1515         return length;
1516 }
1517
1518 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
1519                                    size_t count, loff_t *ppos)
1520 {
1521         struct inode * inode = file->f_dentry->d_inode;
1522         char *page;
1523         ssize_t length;
1524         struct task_struct *task = proc_task(inode);
1525
1526         if (count > PAGE_SIZE)
1527                 count = PAGE_SIZE;
1528         if (*ppos != 0) {
1529                 /* No partial writes. */
1530                 return -EINVAL;
1531         }
1532         page = (char*)__get_free_page(GFP_USER);
1533         if (!page)
1534                 return -ENOMEM;
1535         length = -EFAULT;
1536         if (copy_from_user(page, buf, count))
1537                 goto out;
1538
1539         length = security_setprocattr(task,
1540                                       (char*)file->f_dentry->d_name.name,
1541                                       (void*)page, count);
1542 out:
1543         free_page((unsigned long) page);
1544         return length;
1545 }
1546
1547 static struct file_operations proc_pid_attr_operations = {
1548         .read           = proc_pid_attr_read,
1549         .write          = proc_pid_attr_write,
1550 };
1551
1552 static struct file_operations proc_tid_attr_operations;
1553 static struct inode_operations proc_tid_attr_inode_operations;
1554 static struct file_operations proc_tgid_attr_operations;
1555 static struct inode_operations proc_tgid_attr_inode_operations;
1556 #endif
1557
1558 static int get_tid_list(int index, unsigned int *tids, struct inode *dir);
1559
1560 /* SMP-safe */
1561 static struct dentry *proc_pident_lookup(struct inode *dir,
1562                                          struct dentry *dentry,
1563                                          struct pid_entry *ents)
1564 {
1565         struct inode *inode;
1566         int error;
1567         struct task_struct *task = proc_task(dir);
1568         struct pid_entry *p;
1569         struct proc_inode *ei;
1570
1571         error = -ENOENT;
1572         inode = NULL;
1573
1574         if (!pid_alive(task))
1575                 goto out;
1576
1577         for (p = ents; p->name; p++) {
1578                 if (p->len != dentry->d_name.len)
1579                         continue;
1580                 if (!memcmp(dentry->d_name.name, p->name, p->len))
1581                         break;
1582         }
1583         if (!p->name)
1584                 goto out;
1585
1586         error = -EINVAL;
1587         inode = proc_pid_make_inode(dir->i_sb, task, p->type);
1588         if (!inode)
1589                 goto out;
1590
1591         ei = PROC_I(inode);
1592         inode->i_mode = p->mode;
1593         /*
1594          * Yes, it does not scale. And it should not. Don't add
1595          * new entries into /proc/<tgid>/ without very good reasons.
1596          */
1597         switch(p->type) {
1598                 case PROC_TGID_TASK:
1599                         inode->i_nlink = 2 + get_tid_list(2, NULL, dir);
1600                         inode->i_op = &proc_task_inode_operations;
1601                         inode->i_fop = &proc_task_operations;
1602                         break;
1603                 case PROC_TID_FD:
1604                 case PROC_TGID_FD:
1605                         inode->i_nlink = 2;
1606                         inode->i_op = &proc_fd_inode_operations;
1607                         inode->i_fop = &proc_fd_operations;
1608                         break;
1609                 case PROC_TID_EXE:
1610                 case PROC_TGID_EXE:
1611                         inode->i_op = &proc_pid_link_inode_operations;
1612                         ei->op.proc_get_link = proc_exe_link;
1613                         break;
1614                 case PROC_TID_CWD:
1615                 case PROC_TGID_CWD:
1616                         inode->i_op = &proc_pid_link_inode_operations;
1617                         ei->op.proc_get_link = proc_cwd_link;
1618                         break;
1619                 case PROC_TID_ROOT:
1620                 case PROC_TGID_ROOT:
1621                         inode->i_op = &proc_pid_link_inode_operations;
1622                         ei->op.proc_get_link = proc_root_link;
1623                         break;
1624                 case PROC_TID_ENVIRON:
1625                 case PROC_TGID_ENVIRON:
1626                         inode->i_fop = &proc_info_file_operations;
1627                         ei->op.proc_read = proc_pid_environ;
1628                         break;
1629                 case PROC_TID_AUXV:
1630                 case PROC_TGID_AUXV:
1631                         inode->i_fop = &proc_info_file_operations;
1632                         ei->op.proc_read = proc_pid_auxv;
1633                         break;
1634                 case PROC_TID_STATUS:
1635                 case PROC_TGID_STATUS:
1636                         inode->i_fop = &proc_info_file_operations;
1637                         ei->op.proc_read = proc_pid_status;
1638                         break;
1639                 case PROC_TID_STAT:
1640                         inode->i_fop = &proc_info_file_operations;
1641                         ei->op.proc_read = proc_tid_stat;
1642                         break;
1643                 case PROC_TGID_STAT:
1644                         inode->i_fop = &proc_info_file_operations;
1645                         ei->op.proc_read = proc_tgid_stat;
1646                         break;
1647                 case PROC_TID_CMDLINE:
1648                 case PROC_TGID_CMDLINE:
1649                         inode->i_fop = &proc_info_file_operations;
1650                         ei->op.proc_read = proc_pid_cmdline;
1651                         break;
1652                 case PROC_TID_STATM:
1653                 case PROC_TGID_STATM:
1654                         inode->i_fop = &proc_info_file_operations;
1655                         ei->op.proc_read = proc_pid_statm;
1656                         break;
1657                 case PROC_TID_MAPS:
1658                 case PROC_TGID_MAPS:
1659                         inode->i_fop = &proc_maps_operations;
1660                         break;
1661 #ifdef CONFIG_NUMA
1662                 case PROC_TID_NUMA_MAPS:
1663                 case PROC_TGID_NUMA_MAPS:
1664                         inode->i_fop = &proc_numa_maps_operations;
1665                         break;
1666 #endif
1667                 case PROC_TID_MEM:
1668                 case PROC_TGID_MEM:
1669                         inode->i_op = &proc_mem_inode_operations;
1670                         inode->i_fop = &proc_mem_operations;
1671                         break;
1672 #ifdef CONFIG_SECCOMP
1673                 case PROC_TID_SECCOMP:
1674                 case PROC_TGID_SECCOMP:
1675                         inode->i_fop = &proc_seccomp_operations;
1676                         break;
1677 #endif /* CONFIG_SECCOMP */
1678                 case PROC_TID_MOUNTS:
1679                 case PROC_TGID_MOUNTS:
1680                         inode->i_fop = &proc_mounts_operations;
1681                         break;
1682                 case PROC_TID_SMAPS:
1683                 case PROC_TGID_SMAPS:
1684                         inode->i_fop = &proc_smaps_operations;
1685                         break;
1686 #ifdef CONFIG_SECURITY
1687                 case PROC_TID_ATTR:
1688                         inode->i_nlink = 2;
1689                         inode->i_op = &proc_tid_attr_inode_operations;
1690                         inode->i_fop = &proc_tid_attr_operations;
1691                         break;
1692                 case PROC_TGID_ATTR:
1693                         inode->i_nlink = 2;
1694                         inode->i_op = &proc_tgid_attr_inode_operations;
1695                         inode->i_fop = &proc_tgid_attr_operations;
1696                         break;
1697                 case PROC_TID_ATTR_CURRENT:
1698                 case PROC_TGID_ATTR_CURRENT:
1699                 case PROC_TID_ATTR_PREV:
1700                 case PROC_TGID_ATTR_PREV:
1701                 case PROC_TID_ATTR_EXEC:
1702                 case PROC_TGID_ATTR_EXEC:
1703                 case PROC_TID_ATTR_FSCREATE:
1704                 case PROC_TGID_ATTR_FSCREATE:
1705                         inode->i_fop = &proc_pid_attr_operations;
1706                         break;
1707 #endif
1708 #ifdef CONFIG_KALLSYMS
1709                 case PROC_TID_WCHAN:
1710                 case PROC_TGID_WCHAN:
1711                         inode->i_fop = &proc_info_file_operations;
1712                         ei->op.proc_read = proc_pid_wchan;
1713                         break;
1714 #endif
1715 #ifdef CONFIG_SCHEDSTATS
1716                 case PROC_TID_SCHEDSTAT:
1717                 case PROC_TGID_SCHEDSTAT:
1718                         inode->i_fop = &proc_info_file_operations;
1719                         ei->op.proc_read = proc_pid_schedstat;
1720                         break;
1721 #endif
1722 #ifdef CONFIG_CPUSETS
1723                 case PROC_TID_CPUSET:
1724                 case PROC_TGID_CPUSET:
1725                         inode->i_fop = &proc_cpuset_operations;
1726                         break;
1727 #endif
1728                 case PROC_TID_OOM_SCORE:
1729                 case PROC_TGID_OOM_SCORE:
1730                         inode->i_fop = &proc_info_file_operations;
1731                         ei->op.proc_read = proc_oom_score;
1732                         break;
1733                 case PROC_TID_OOM_ADJUST:
1734                 case PROC_TGID_OOM_ADJUST:
1735                         inode->i_fop = &proc_oom_adjust_operations;
1736                         break;
1737 #ifdef CONFIG_AUDITSYSCALL
1738                 case PROC_TID_LOGINUID:
1739                 case PROC_TGID_LOGINUID:
1740                         inode->i_fop = &proc_loginuid_operations;
1741                         break;
1742 #endif
1743                 default:
1744                         printk("procfs: impossible type (%d)",p->type);
1745                         iput(inode);
1746                         return ERR_PTR(-EINVAL);
1747         }
1748         dentry->d_op = &pid_dentry_operations;
1749         d_add(dentry, inode);
1750         return NULL;
1751
1752 out:
1753         return ERR_PTR(error);
1754 }
1755
1756 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1757         return proc_pident_lookup(dir, dentry, tgid_base_stuff);
1758 }
1759
1760 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1761         return proc_pident_lookup(dir, dentry, tid_base_stuff);
1762 }
1763
1764 static struct file_operations proc_tgid_base_operations = {
1765         .read           = generic_read_dir,
1766         .readdir        = proc_tgid_base_readdir,
1767 };
1768
1769 static struct file_operations proc_tid_base_operations = {
1770         .read           = generic_read_dir,
1771         .readdir        = proc_tid_base_readdir,
1772 };
1773
1774 static struct inode_operations proc_tgid_base_inode_operations = {
1775         .lookup         = proc_tgid_base_lookup,
1776 };
1777
1778 static struct inode_operations proc_tid_base_inode_operations = {
1779         .lookup         = proc_tid_base_lookup,
1780 };
1781
1782 #ifdef CONFIG_SECURITY
1783 static int proc_tgid_attr_readdir(struct file * filp,
1784                              void * dirent, filldir_t filldir)
1785 {
1786         return proc_pident_readdir(filp,dirent,filldir,
1787                                    tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
1788 }
1789
1790 static int proc_tid_attr_readdir(struct file * filp,
1791                              void * dirent, filldir_t filldir)
1792 {
1793         return proc_pident_readdir(filp,dirent,filldir,
1794                                    tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
1795 }
1796
1797 static struct file_operations proc_tgid_attr_operations = {
1798         .read           = generic_read_dir,
1799         .readdir        = proc_tgid_attr_readdir,
1800 };
1801
1802 static struct file_operations proc_tid_attr_operations = {
1803         .read           = generic_read_dir,
1804         .readdir        = proc_tid_attr_readdir,
1805 };
1806
1807 static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
1808                                 struct dentry *dentry, struct nameidata *nd)
1809 {
1810         return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
1811 }
1812
1813 static struct dentry *proc_tid_attr_lookup(struct inode *dir,
1814                                 struct dentry *dentry, struct nameidata *nd)
1815 {
1816         return proc_pident_lookup(dir, dentry, tid_attr_stuff);
1817 }
1818
1819 static struct inode_operations proc_tgid_attr_inode_operations = {
1820         .lookup         = proc_tgid_attr_lookup,
1821 };
1822
1823 static struct inode_operations proc_tid_attr_inode_operations = {
1824         .lookup         = proc_tid_attr_lookup,
1825 };
1826 #endif
1827
1828 /*
1829  * /proc/self:
1830  */
1831 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
1832                               int buflen)
1833 {
1834         char tmp[30];
1835         sprintf(tmp, "%d", current->tgid);
1836         return vfs_readlink(dentry,buffer,buflen,tmp);
1837 }
1838
1839 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
1840 {
1841         char tmp[30];
1842         sprintf(tmp, "%d", current->tgid);
1843         return ERR_PTR(vfs_follow_link(nd,tmp));
1844 }
1845
1846 static struct inode_operations proc_self_inode_operations = {
1847         .readlink       = proc_self_readlink,
1848         .follow_link    = proc_self_follow_link,
1849 };
1850
1851 /**
1852  * proc_pid_unhash -  Unhash /proc/@pid entry from the dcache.
1853  * @p: task that should be flushed.
1854  *
1855  * Drops the /proc/@pid dcache entry from the hash chains.
1856  *
1857  * Dropping /proc/@pid entries and detach_pid must be synchroneous,
1858  * otherwise e.g. /proc/@pid/exe might point to the wrong executable,
1859  * if the pid value is immediately reused. This is enforced by
1860  * - caller must acquire spin_lock(p->proc_lock)
1861  * - must be called before detach_pid()
1862  * - proc_pid_lookup acquires proc_lock, and checks that
1863  *   the target is not dead by looking at the attach count
1864  *   of PIDTYPE_PID.
1865  */
1866
1867 struct dentry *proc_pid_unhash(struct task_struct *p)
1868 {
1869         struct dentry *proc_dentry;
1870
1871         proc_dentry = p->proc_dentry;
1872         if (proc_dentry != NULL) {
1873
1874                 spin_lock(&dcache_lock);
1875                 spin_lock(&proc_dentry->d_lock);
1876                 if (!d_unhashed(proc_dentry)) {
1877                         dget_locked(proc_dentry);
1878                         __d_drop(proc_dentry);
1879                         spin_unlock(&proc_dentry->d_lock);
1880                 } else {
1881                         spin_unlock(&proc_dentry->d_lock);
1882                         proc_dentry = NULL;
1883                 }
1884                 spin_unlock(&dcache_lock);
1885         }
1886         return proc_dentry;
1887 }
1888
1889 /**
1890  * proc_pid_flush - recover memory used by stale /proc/@pid/x entries
1891  * @proc_dentry: directoy to prune.
1892  *
1893  * Shrink the /proc directory that was used by the just killed thread.
1894  */
1895
1896 void proc_pid_flush(struct dentry *proc_dentry)
1897 {
1898         might_sleep();
1899         if(proc_dentry != NULL) {
1900                 shrink_dcache_parent(proc_dentry);
1901                 dput(proc_dentry);
1902         }
1903 }
1904
1905 /* SMP-safe */
1906 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1907 {
1908         struct task_struct *task;
1909         struct inode *inode;
1910         struct proc_inode *ei;
1911         unsigned tgid;
1912         int died;
1913
1914         if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
1915                 inode = new_inode(dir->i_sb);
1916                 if (!inode)
1917                         return ERR_PTR(-ENOMEM);
1918                 ei = PROC_I(inode);
1919                 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1920                 inode->i_ino = fake_ino(0, PROC_TGID_INO);
1921                 ei->pde = NULL;
1922                 inode->i_mode = S_IFLNK|S_IRWXUGO;
1923                 inode->i_uid = inode->i_gid = 0;
1924                 inode->i_size = 64;
1925                 inode->i_op = &proc_self_inode_operations;
1926                 d_add(dentry, inode);
1927                 return NULL;
1928         }
1929         tgid = name_to_int(dentry);
1930         if (tgid == ~0U)
1931                 goto out;
1932
1933         read_lock(&tasklist_lock);
1934         task = find_task_by_pid(tgid);
1935         if (task)
1936                 get_task_struct(task);
1937         read_unlock(&tasklist_lock);
1938         if (!task)
1939                 goto out;
1940
1941         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
1942
1943
1944         if (!inode) {
1945                 put_task_struct(task);
1946                 goto out;
1947         }
1948         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
1949         inode->i_op = &proc_tgid_base_inode_operations;
1950         inode->i_fop = &proc_tgid_base_operations;
1951         inode->i_flags|=S_IMMUTABLE;
1952 #ifdef CONFIG_SECURITY
1953         inode->i_nlink = 5;
1954 #else
1955         inode->i_nlink = 4;
1956 #endif
1957
1958         dentry->d_op = &pid_base_dentry_operations;
1959
1960         died = 0;
1961         d_add(dentry, inode);
1962         spin_lock(&task->proc_lock);
1963         task->proc_dentry = dentry;
1964         if (!pid_alive(task)) {
1965                 dentry = proc_pid_unhash(task);
1966                 died = 1;
1967         }
1968         spin_unlock(&task->proc_lock);
1969
1970         put_task_struct(task);
1971         if (died) {
1972                 proc_pid_flush(dentry);
1973                 goto out;
1974         }
1975         return NULL;
1976 out:
1977         return ERR_PTR(-ENOENT);
1978 }
1979
1980 /* SMP-safe */
1981 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1982 {
1983         struct task_struct *task;
1984         struct task_struct *leader = proc_task(dir);
1985         struct inode *inode;
1986         unsigned tid;
1987
1988         tid = name_to_int(dentry);
1989         if (tid == ~0U)
1990                 goto out;
1991
1992         read_lock(&tasklist_lock);
1993         task = find_task_by_pid(tid);
1994         if (task)
1995                 get_task_struct(task);
1996         read_unlock(&tasklist_lock);
1997         if (!task)
1998                 goto out;
1999         if (leader->tgid != task->tgid)
2000                 goto out_drop_task;
2001
2002         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);
2003
2004
2005         if (!inode)
2006                 goto out_drop_task;
2007         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2008         inode->i_op = &proc_tid_base_inode_operations;
2009         inode->i_fop = &proc_tid_base_operations;
2010         inode->i_flags|=S_IMMUTABLE;
2011 #ifdef CONFIG_SECURITY
2012         inode->i_nlink = 4;
2013 #else
2014         inode->i_nlink = 3;
2015 #endif
2016
2017         dentry->d_op = &pid_base_dentry_operations;
2018
2019         d_add(dentry, inode);
2020
2021         put_task_struct(task);
2022         return NULL;
2023 out_drop_task:
2024         put_task_struct(task);
2025 out:
2026         return ERR_PTR(-ENOENT);
2027 }
2028
2029 #define PROC_NUMBUF 10
2030 #define PROC_MAXPIDS 20
2031
2032 /*
2033  * Get a few tgid's to return for filldir - we need to hold the
2034  * tasklist lock while doing this, and we must release it before
2035  * we actually do the filldir itself, so we use a temp buffer..
2036  */
2037 static int get_tgid_list(int index, unsigned long version, unsigned int *tgids)
2038 {
2039         struct task_struct *p;
2040         int nr_tgids = 0;
2041
2042         index--;
2043         read_lock(&tasklist_lock);
2044         p = NULL;
2045         if (version) {
2046                 p = find_task_by_pid(version);
2047                 if (p && !thread_group_leader(p))
2048                         p = NULL;
2049         }
2050
2051         if (p)
2052                 index = 0;
2053         else
2054                 p = next_task(&init_task);
2055
2056         for ( ; p != &init_task; p = next_task(p)) {
2057                 int tgid = p->pid;
2058                 if (!pid_alive(p))
2059                         continue;
2060                 if (--index >= 0)
2061                         continue;
2062                 tgids[nr_tgids] = tgid;
2063                 nr_tgids++;
2064                 if (nr_tgids >= PROC_MAXPIDS)
2065                         break;
2066         }
2067         read_unlock(&tasklist_lock);
2068         return nr_tgids;
2069 }
2070
2071 /*
2072  * Get a few tid's to return for filldir - we need to hold the
2073  * tasklist lock while doing this, and we must release it before
2074  * we actually do the filldir itself, so we use a temp buffer..
2075  */
2076 static int get_tid_list(int index, unsigned int *tids, struct inode *dir)
2077 {
2078         struct task_struct *leader_task = proc_task(dir);
2079         struct task_struct *task = leader_task;
2080         int nr_tids = 0;
2081
2082         index -= 2;
2083         read_lock(&tasklist_lock);
2084         /*
2085          * The starting point task (leader_task) might be an already
2086          * unlinked task, which cannot be used to access the task-list
2087          * via next_thread().
2088          */
2089         if (pid_alive(task)) do {
2090                 int tid = task->pid;
2091
2092                 if (--index >= 0)
2093                         continue;
2094                 if (tids != NULL)
2095                         tids[nr_tids] = tid;
2096                 nr_tids++;
2097                 if (nr_tids >= PROC_MAXPIDS)
2098                         break;
2099         } while ((task = next_thread(task)) != leader_task);
2100         read_unlock(&tasklist_lock);
2101         return nr_tids;
2102 }
2103
2104 /* for the /proc/ directory itself, after non-process stuff has been done */
2105 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2106 {
2107         unsigned int tgid_array[PROC_MAXPIDS];
2108         char buf[PROC_NUMBUF];
2109         unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2110         unsigned int nr_tgids, i;
2111         int next_tgid;
2112
2113         if (!nr) {
2114                 ino_t ino = fake_ino(0,PROC_TGID_INO);
2115                 if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
2116                         return 0;
2117                 filp->f_pos++;
2118                 nr++;
2119         }
2120
2121         /* f_version caches the tgid value that the last readdir call couldn't
2122          * return. lseek aka telldir automagically resets f_version to 0.
2123          */
2124         next_tgid = filp->f_version;
2125         filp->f_version = 0;
2126         for (;;) {
2127                 nr_tgids = get_tgid_list(nr, next_tgid, tgid_array);
2128                 if (!nr_tgids) {
2129                         /* no more entries ! */
2130                         break;
2131                 }
2132                 next_tgid = 0;
2133
2134                 /* do not use the last found pid, reserve it for next_tgid */
2135                 if (nr_tgids == PROC_MAXPIDS) {
2136                         nr_tgids--;
2137                         next_tgid = tgid_array[nr_tgids];
2138                 }
2139
2140                 for (i=0;i<nr_tgids;i++) {
2141                         int tgid = tgid_array[i];
2142                         ino_t ino = fake_ino(tgid,PROC_TGID_INO);
2143                         unsigned long j = PROC_NUMBUF;
2144
2145                         do
2146                                 buf[--j] = '0' + (tgid % 10);
2147                         while ((tgid /= 10) != 0);
2148
2149                         if (filldir(dirent, buf+j, PROC_NUMBUF-j, filp->f_pos, ino, DT_DIR) < 0) {
2150                                 /* returning this tgid failed, save it as the first
2151                                  * pid for the next readir call */
2152                                 filp->f_version = tgid_array[i];
2153                                 goto out;
2154                         }
2155                         filp->f_pos++;
2156                         nr++;
2157                 }
2158         }
2159 out:
2160         return 0;
2161 }
2162
2163 /* for the /proc/TGID/task/ directories */
2164 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
2165 {
2166         unsigned int tid_array[PROC_MAXPIDS];
2167         char buf[PROC_NUMBUF];
2168         unsigned int nr_tids, i;
2169         struct dentry *dentry = filp->f_dentry;
2170         struct inode *inode = dentry->d_inode;
2171         int retval = -ENOENT;
2172         ino_t ino;
2173         unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
2174
2175         if (!pid_alive(proc_task(inode)))
2176                 goto out;
2177         retval = 0;
2178
2179         switch (pos) {
2180         case 0:
2181                 ino = inode->i_ino;
2182                 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
2183                         goto out;
2184                 pos++;
2185                 /* fall through */
2186         case 1:
2187                 ino = parent_ino(dentry);
2188                 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
2189                         goto out;
2190                 pos++;
2191                 /* fall through */
2192         }
2193
2194         nr_tids = get_tid_list(pos, tid_array, inode);
2195         inode->i_nlink = pos + nr_tids;
2196
2197         for (i = 0; i < nr_tids; i++) {
2198                 unsigned long j = PROC_NUMBUF;
2199                 int tid = tid_array[i];
2200
2201                 ino = fake_ino(tid,PROC_TID_INO);
2202
2203                 do
2204                         buf[--j] = '0' + (tid % 10);
2205                 while ((tid /= 10) != 0);
2206
2207                 if (filldir(dirent, buf+j, PROC_NUMBUF-j, pos, ino, DT_DIR) < 0)
2208                         break;
2209                 pos++;
2210         }
2211 out:
2212         filp->f_pos = pos;
2213         return retval;
2214 }