fs/proc/base.c

   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/capability.h>
  59 #include <linux/file.h>
  60 #include <linux/string.h>
  61 #include <linux/seq_file.h>
  62 #include <linux/namei.h>
  63 #include <linux/namespace.h>
  64 #include <linux/mm.h>
  65 #include <linux/smp_lock.h>
  66 #include <linux/rcupdate.h>
  67 #include <linux/kallsyms.h>
  68 #include <linux/mount.h>
  69 #include <linux/security.h>
  70 #include <linux/ptrace.h>
  71 #include <linux/seccomp.h>
  72 #include <linux/cpuset.h>
  73 #include <linux/audit.h>
  74 #include <linux/poll.h>
  75 #include "internal.h"
  76
  77 /* NOTE:
  78  *      Implementing inode permission operations in /proc is almost
  79  *      certainly an error.  Permission checks need to happen during
  80  *      each system call not at open time.  The reason is that most of
  81  *      what we wish to check for permissions in /proc varies at runtime.
  82  *
  83  *      The classic example of a problem is opening file descriptors
  84  *      in /proc for a task before it execs a suid executable.
  85  */
  86
  87 /*
  88  * For hysterical raisins we keep the same inumbers as in the old procfs.
  89  * Feel free to change the macro below - just keep the range distinct from
  90  * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
  91  * As soon as we'll get a separate superblock we will be able to forget
  92  * about magical ranges too.
  93  */
  94
  95 #define fake_ino(pid,ino) (((pid)<<16)|(ino))
  96
  97 enum pid_directory_inos {
  98         PROC_TGID_INO = 2,
  99         PROC_TGID_TASK,
 100         PROC_TGID_STATUS,
 101         PROC_TGID_MEM,
 102 #ifdef CONFIG_SECCOMP
 103         PROC_TGID_SECCOMP,
 104 #endif
 105         PROC_TGID_CWD,
 106         PROC_TGID_ROOT,
 107         PROC_TGID_EXE,
 108         PROC_TGID_FD,
 109         PROC_TGID_ENVIRON,
 110         PROC_TGID_AUXV,
 111         PROC_TGID_CMDLINE,
 112         PROC_TGID_STAT,
 113         PROC_TGID_STATM,
 114         PROC_TGID_MAPS,
 115         PROC_TGID_NUMA_MAPS,
 116         PROC_TGID_MOUNTS,
 117         PROC_TGID_MOUNTSTATS,
 118         PROC_TGID_WCHAN,
 119 #ifdef CONFIG_MMU
 120         PROC_TGID_SMAPS,
 121 #endif
 122 #ifdef CONFIG_SCHEDSTATS
 123         PROC_TGID_SCHEDSTAT,
 124 #endif
 125 #ifdef CONFIG_CPUSETS
 126         PROC_TGID_CPUSET,
 127 #endif
 128 #ifdef CONFIG_SECURITY
 129         PROC_TGID_ATTR,
 130         PROC_TGID_ATTR_CURRENT,
 131         PROC_TGID_ATTR_PREV,
 132         PROC_TGID_ATTR_EXEC,
 133         PROC_TGID_ATTR_FSCREATE,
 134         PROC_TGID_ATTR_KEYCREATE,
 135 #endif
 136 #ifdef CONFIG_AUDITSYSCALL
 137         PROC_TGID_LOGINUID,
 138 #endif
 139         PROC_TGID_OOM_SCORE,
 140         PROC_TGID_OOM_ADJUST,
 141         PROC_TID_INO,
 142         PROC_TID_STATUS,
 143         PROC_TID_MEM,
 144 #ifdef CONFIG_SECCOMP
 145         PROC_TID_SECCOMP,
 146 #endif
 147         PROC_TID_CWD,
 148         PROC_TID_ROOT,
 149         PROC_TID_EXE,
 150         PROC_TID_FD,
 151         PROC_TID_ENVIRON,
 152         PROC_TID_AUXV,
 153         PROC_TID_CMDLINE,
 154         PROC_TID_STAT,
 155         PROC_TID_STATM,
 156         PROC_TID_MAPS,
 157         PROC_TID_NUMA_MAPS,
 158         PROC_TID_MOUNTS,
 159         PROC_TID_MOUNTSTATS,
 160         PROC_TID_WCHAN,
 161 #ifdef CONFIG_MMU
 162         PROC_TID_SMAPS,
 163 #endif
 164 #ifdef CONFIG_SCHEDSTATS
 165         PROC_TID_SCHEDSTAT,
 166 #endif
 167 #ifdef CONFIG_CPUSETS
 168         PROC_TID_CPUSET,
 169 #endif
 170 #ifdef CONFIG_SECURITY
 171         PROC_TID_ATTR,
 172         PROC_TID_ATTR_CURRENT,
 173         PROC_TID_ATTR_PREV,
 174         PROC_TID_ATTR_EXEC,
 175         PROC_TID_ATTR_FSCREATE,
 176         PROC_TID_ATTR_KEYCREATE,
 177 #endif
 178 #ifdef CONFIG_AUDITSYSCALL
 179         PROC_TID_LOGINUID,
 180 #endif
 181         PROC_TID_OOM_SCORE,
 182         PROC_TID_OOM_ADJUST,
 183
 184         /* Add new entries before this */
 185         PROC_TID_FD_DIR = 0x8000,       /* 0x8000-0xffff */
 186 };
 187
 188 struct pid_entry {
 189         int type;
 190         int len;
 191         char *name;
 192         mode_t mode;
 193 };
 194
 195 #define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}
 196
 197 static struct pid_entry tgid_base_stuff[] = {
 198         E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
 199         E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
 200         E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
 201         E(PROC_TGID_AUXV,      "auxv",    S_IFREG|S_IRUSR),
 202         E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
 203         E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
 204         E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
 205         E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
 206         E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
 207 #ifdef CONFIG_NUMA
 208         E(PROC_TGID_NUMA_MAPS, "numa_maps", S_IFREG|S_IRUGO),
 209 #endif
 210         E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 211 #ifdef CONFIG_SECCOMP
 212         E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
 213 #endif
 214         E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
 215         E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
 216         E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
 217         E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
 218         E(PROC_TGID_MOUNTSTATS, "mountstats", S_IFREG|S_IRUSR),
 219 #ifdef CONFIG_MMU
 220         E(PROC_TGID_SMAPS,     "smaps",   S_IFREG|S_IRUGO),
 221 #endif
 222 #ifdef CONFIG_SECURITY
 223         E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
 224 #endif
 225 #ifdef CONFIG_KALLSYMS
 226         E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
 227 #endif
 228 #ifdef CONFIG_SCHEDSTATS
 229         E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
 230 #endif
 231 #ifdef CONFIG_CPUSETS
 232         E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
 233 #endif
 234         E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
 235         E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
 236 #ifdef CONFIG_AUDITSYSCALL
 237         E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 238 #endif
 239         {0,0,NULL,0}
 240 };
 241 static struct pid_entry tid_base_stuff[] = {
 242         E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
 243         E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
 244         E(PROC_TID_AUXV,       "auxv",    S_IFREG|S_IRUSR),
 245         E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
 246         E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
 247         E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
 248         E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
 249         E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
 250 #ifdef CONFIG_NUMA
 251         E(PROC_TID_NUMA_MAPS,  "numa_maps",    S_IFREG|S_IRUGO),
 252 #endif
 253         E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 254 #ifdef CONFIG_SECCOMP
 255         E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
 256 #endif
 257         E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
 258         E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
 259         E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
 260         E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
 261 #ifdef CONFIG_MMU
 262         E(PROC_TID_SMAPS,      "smaps",   S_IFREG|S_IRUGO),
 263 #endif
 264 #ifdef CONFIG_SECURITY
 265         E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
 266 #endif
 267 #ifdef CONFIG_KALLSYMS
 268         E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
 269 #endif
 270 #ifdef CONFIG_SCHEDSTATS
 271         E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
 272 #endif
 273 #ifdef CONFIG_CPUSETS
 274         E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
 275 #endif
 276         E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
 277         E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
 278 #ifdef CONFIG_AUDITSYSCALL
 279         E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 280 #endif
 281         {0,0,NULL,0}
 282 };
 283
 284 #ifdef CONFIG_SECURITY
 285 static struct pid_entry tgid_attr_stuff[] = {
 286         E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
 287         E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
 288         E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
 289         E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 290         E(PROC_TGID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
 291         {0,0,NULL,0}
 292 };
 293 static struct pid_entry tid_attr_stuff[] = {
 294         E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
 295         E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
 296         E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
 297         E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 298         E(PROC_TID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
 299         {0,0,NULL,0}
 300 };
 301 #endif
 302
 303 #undef E
 304
 305 static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 306 {
 307         struct task_struct *task = proc_task(inode);
 308         struct files_struct *files;
 309         struct file *file;
 310         int fd = proc_fd(inode);
 311
 312         files = get_files_struct(task);
 313         if (files) {
 314                 /*
 315                  * We are not taking a ref to the file structure, so we must
 316                  * hold ->file_lock.
 317                  */
 318                 spin_lock(&files->file_lock);
 319                 file = fcheck_files(files, fd);
 320                 if (file) {
 321                         *mnt = mntget(file->f_vfsmnt);
 322                         *dentry = dget(file->f_dentry);
 323                         spin_unlock(&files->file_lock);
 324                         put_files_struct(files);
 325                         return 0;
 326                 }
 327                 spin_unlock(&files->file_lock);
 328                 put_files_struct(files);
 329         }
 330         return -ENOENT;
 331 }
 332
 333 static struct fs_struct *get_fs_struct(struct task_struct *task)
 334 {
 335         struct fs_struct *fs;
 336         task_lock(task);
 337         fs = task->fs;
 338         if(fs)
 339                 atomic_inc(&fs->count);
 340         task_unlock(task);
 341         return fs;
 342 }
 343
 344 static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 345 {
 346         struct fs_struct *fs = get_fs_struct(proc_task(inode));
 347         int result = -ENOENT;
 348         if (fs) {
 349                 read_lock(&fs->lock);
 350                 *mnt = mntget(fs->pwdmnt);
 351                 *dentry = dget(fs->pwd);
 352                 read_unlock(&fs->lock);
 353                 result = 0;
 354                 put_fs_struct(fs);
 355         }
 356         return result;
 357 }
 358
 359 static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 360 {
 361         struct fs_struct *fs = get_fs_struct(proc_task(inode));
 362         int result = -ENOENT;
 363         if (fs) {
 364                 read_lock(&fs->lock);
 365                 *mnt = mntget(fs->rootmnt);
 366                 *dentry = dget(fs->root);
 367                 read_unlock(&fs->lock);
 368                 result = 0;
 369                 put_fs_struct(fs);
 370         }
 371         return result;
 372 }
 373
 374 #define MAY_PTRACE(task) \
 375         (task == current || \
 376         (task->parent == current && \
 377         (task->ptrace & PT_PTRACED) && \
 378          (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
 379          security_ptrace(current,task) == 0))
 380
 381 static int proc_pid_environ(struct task_struct *task, char * buffer)
 382 {
 383         int res = 0;
 384         struct mm_struct *mm = get_task_mm(task);
 385         if (mm) {
 386                 unsigned int len = mm->env_end - mm->env_start;
 387                 if (len > PAGE_SIZE)
 388                         len = PAGE_SIZE;
 389                 res = access_process_vm(task, mm->env_start, buffer, len, 0);
 390                 if (!ptrace_may_attach(task))
 391                         res = -ESRCH;
 392                 mmput(mm);
 393         }
 394         return res;
 395 }
 396
 397 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 398 {
 399         int res = 0;
 400         unsigned int len;
 401         struct mm_struct *mm = get_task_mm(task);
 402         if (!mm)
 403                 goto out;
 404         if (!mm->arg_end)
 405                 goto out_mm;    /* Shh! No looking before we're done */
 406
 407         len = mm->arg_end - mm->arg_start;
 408
 409         if (len > PAGE_SIZE)
 410                 len = PAGE_SIZE;
 411
 412         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 413
 414         // If the nul at the end of args has been overwritten, then
 415         // assume application is using setproctitle(3).
 416         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 417                 len = strnlen(buffer, res);
 418                 if (len < res) {
 419                     res = len;
 420                 } else {
 421                         len = mm->env_end - mm->env_start;
 422                         if (len > PAGE_SIZE - res)
 423                                 len = PAGE_SIZE - res;
 424                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 425                         res = strnlen(buffer, res);
 426                 }
 427         }
 428 out_mm:
 429         mmput(mm);
 430 out:
 431         return res;
 432 }
 433
 434 static int proc_pid_auxv(struct task_struct *task, char *buffer)
 435 {
 436         int res = 0;
 437         struct mm_struct *mm = get_task_mm(task);
 438         if (mm) {
 439                 unsigned int nwords = 0;
 440                 do
 441                         nwords += 2;
 442                 while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 443                 res = nwords * sizeof(mm->saved_auxv[0]);
 444                 if (res > PAGE_SIZE)
 445                         res = PAGE_SIZE;
 446                 memcpy(buffer, mm->saved_auxv, res);
 447                 mmput(mm);
 448         }
 449         return res;
 450 }
 451
 452
 453 #ifdef CONFIG_KALLSYMS
 454 /*
 455  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 456  * Returns the resolved symbol.  If that fails, simply return the address.
 457  */
 458 static int proc_pid_wchan(struct task_struct *task, char *buffer)
 459 {
 460         char *modname;
 461         const char *sym_name;
 462         unsigned long wchan, size, offset;
 463         char namebuf[KSYM_NAME_LEN+1];
 464
 465         wchan = get_wchan(task);
 466
 467         sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
 468         if (sym_name)
 469                 return sprintf(buffer, "%s", sym_name);
 470         return sprintf(buffer, "%lu", wchan);
 471 }
 472 #endif /* CONFIG_KALLSYMS */
 473
 474 #ifdef CONFIG_SCHEDSTATS
 475 /*
 476  * Provides /proc/PID/schedstat
 477  */
 478 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 479 {
 480         return sprintf(buffer, "%lu %lu %lu\n",
 481                         task->sched_info.cpu_time,
 482                         task->sched_info.run_delay,
 483                         task->sched_info.pcnt);
 484 }
 485 #endif
 486
 487 /* The badness from the OOM killer */
 488 unsigned long badness(struct task_struct *p, unsigned long uptime);
 489 static int proc_oom_score(struct task_struct *task, char *buffer)
 490 {
 491         unsigned long points;
 492         struct timespec uptime;
 493
 494         do_posix_clock_monotonic_gettime(&uptime);
 495         points = badness(task, uptime.tv_sec);
 496         return sprintf(buffer, "%lu\n", points);
 497 }
 498
 499 /************************************************************************/
 500 /*                       Here the fs part begins                        */
 501 /************************************************************************/
 502
 503 /* permission checks */
 504
 505 /* If the process being read is separated by chroot from the reading process,
 506  * don't let the reader access the threads.
 507  */
 508 static int proc_check_chroot(struct dentry *de, struct vfsmount *mnt)
 509 {
 510         struct dentry *base;
 511         struct vfsmount *our_vfsmnt;
 512         int res = 0;
 513
 514         read_lock(&current->fs->lock);
 515         our_vfsmnt = mntget(current->fs->rootmnt);
 516         base = dget(current->fs->root);
 517         read_unlock(&current->fs->lock);
 518
 519         spin_lock(&vfsmount_lock);
 520
 521         while (mnt != our_vfsmnt) {
 522                 if (mnt == mnt->mnt_parent)
 523                         goto out;
 524                 de = mnt->mnt_mountpoint;
 525                 mnt = mnt->mnt_parent;
 526         }
 527
 528         if (!is_subdir(de, base))
 529                 goto out;
 530         spin_unlock(&vfsmount_lock);
 531
 532 exit:
 533         dput(base);
 534         mntput(our_vfsmnt);
 535         return res;
 536 out:
 537         spin_unlock(&vfsmount_lock);
 538         res = -EACCES;
 539         goto exit;
 540 }
 541
 542 extern struct seq_operations mounts_op;
 543 struct proc_mounts {
 544         struct seq_file m;
 545         int event;
 546 };
 547
 548 static int mounts_open(struct inode *inode, struct file *file)
 549 {
 550         struct task_struct *task = proc_task(inode);
 551         struct namespace *namespace;
 552         struct proc_mounts *p;
 553         int ret = -EINVAL;
 554
 555         task_lock(task);
 556         namespace = task->namespace;
 557         if (namespace)
 558                 get_namespace(namespace);
 559         task_unlock(task);
 560
 561         if (namespace) {
 562                 ret = -ENOMEM;
 563                 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
 564                 if (p) {
 565                         file->private_data = &p->m;
 566                         ret = seq_open(file, &mounts_op);
 567                         if (!ret) {
 568                                 p->m.private = namespace;
 569                                 p->event = namespace->event;
 570                                 return 0;
 571                         }
 572                         kfree(p);
 573                 }
 574                 put_namespace(namespace);
 575         }
 576         return ret;
 577 }
 578
 579 static int mounts_release(struct inode *inode, struct file *file)
 580 {
 581         struct seq_file *m = file->private_data;
 582         struct namespace *namespace = m->private;
 583         put_namespace(namespace);
 584         return seq_release(inode, file);
 585 }
 586
 587 static unsigned mounts_poll(struct file *file, poll_table *wait)
 588 {
 589         struct proc_mounts *p = file->private_data;
 590         struct namespace *ns = p->m.private;
 591         unsigned res = 0;
 592
 593         poll_wait(file, &ns->poll, wait);
 594
 595         spin_lock(&vfsmount_lock);
 596         if (p->event != ns->event) {
 597                 p->event = ns->event;
 598                 res = POLLERR;
 599         }
 600         spin_unlock(&vfsmount_lock);
 601
 602         return res;
 603 }
 604
 605 static struct file_operations proc_mounts_operations = {
 606         .open           = mounts_open,
 607         .read           = seq_read,
 608         .llseek         = seq_lseek,
 609         .release        = mounts_release,
 610         .poll           = mounts_poll,
 611 };
 612
 613 extern struct seq_operations mountstats_op;
 614 static int mountstats_open(struct inode *inode, struct file *file)
 615 {
 616         struct task_struct *task = proc_task(inode);
 617         int ret = seq_open(file, &mountstats_op);
 618
 619         if (!ret) {
 620                 struct seq_file *m = file->private_data;
 621                 struct namespace *namespace;
 622                 task_lock(task);
 623                 namespace = task->namespace;
 624                 if (namespace)
 625                         get_namespace(namespace);
 626                 task_unlock(task);
 627
 628                 if (namespace)
 629                         m->private = namespace;
 630                 else {
 631                         seq_release(inode, file);
 632                         ret = -EINVAL;
 633                 }
 634         }
 635         return ret;
 636 }
 637
 638 static struct file_operations proc_mountstats_operations = {
 639         .open           = mountstats_open,
 640         .read           = seq_read,
 641         .llseek         = seq_lseek,
 642         .release        = mounts_release,
 643 };
 644
 645 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 646
 647 static ssize_t proc_info_read(struct file * file, char __user * buf,
 648                           size_t count, loff_t *ppos)
 649 {
 650         struct inode * inode = file->f_dentry->d_inode;
 651         unsigned long page;
 652         ssize_t length;
 653         struct task_struct *task = proc_task(inode);
 654
 655         if (count > PROC_BLOCK_SIZE)
 656                 count = PROC_BLOCK_SIZE;
 657         if (!(page = __get_free_page(GFP_KERNEL)))
 658                 return -ENOMEM;
 659
 660         length = PROC_I(inode)->op.proc_read(task, (char*)page);
 661
 662         if (length >= 0)
 663                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 664         free_page(page);
 665         return length;
 666 }
 667
 668 static struct file_operations proc_info_file_operations = {
 669         .read           = proc_info_read,
 670 };
 671
 672 static int mem_open(struct inode* inode, struct file* file)
 673 {
 674         file->private_data = (void*)((long)current->self_exec_id);
 675         return 0;
 676 }
 677
 678 static ssize_t mem_read(struct file * file, char __user * buf,
 679                         size_t count, loff_t *ppos)
 680 {
 681         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 682         char *page;
 683         unsigned long src = *ppos;
 684         int ret = -ESRCH;
 685         struct mm_struct *mm;
 686
 687         if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
 688                 goto out;
 689
 690         ret = -ENOMEM;
 691         page = (char *)__get_free_page(GFP_USER);
 692         if (!page)
 693                 goto out;
 694
 695         ret = 0;
 696
 697         mm = get_task_mm(task);
 698         if (!mm)
 699                 goto out_free;
 700
 701         ret = -EIO;
 702
 703         if (file->private_data != (void*)((long)current->self_exec_id))
 704                 goto out_put;
 705
 706         ret = 0;
 707
 708         while (count > 0) {
 709                 int this_len, retval;
 710
 711                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 712                 retval = access_process_vm(task, src, page, this_len, 0);
 713                 if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
 714                         if (!ret)
 715                                 ret = -EIO;
 716                         break;
 717                 }
 718
 719                 if (copy_to_user(buf, page, retval)) {
 720                         ret = -EFAULT;
 721                         break;
 722                 }
 723
 724                 ret += retval;
 725                 src += retval;
 726                 buf += retval;
 727                 count -= retval;
 728         }
 729         *ppos = src;
 730
 731 out_put:
 732         mmput(mm);
 733 out_free:
 734         free_page((unsigned long) page);
 735 out:
 736         return ret;
 737 }
 738
 739 #define mem_write NULL
 740
 741 #ifndef mem_write
 742 /* This is a security hazard */
 743 static ssize_t mem_write(struct file * file, const char * buf,
 744                          size_t count, loff_t *ppos)
 745 {
 746         int copied = 0;
 747         char *page;
 748         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 749         unsigned long dst = *ppos;
 750
 751         if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
 752                 return -ESRCH;
 753
 754         page = (char *)__get_free_page(GFP_USER);
 755         if (!page)
 756                 return -ENOMEM;
 757
 758         while (count > 0) {
 759                 int this_len, retval;
 760
 761                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 762                 if (copy_from_user(page, buf, this_len)) {
 763                         copied = -EFAULT;
 764                         break;
 765                 }
 766                 retval = access_process_vm(task, dst, page, this_len, 1);
 767                 if (!retval) {
 768                         if (!copied)
 769                                 copied = -EIO;
 770                         break;
 771                 }
 772                 copied += retval;
 773                 buf += retval;
 774                 dst += retval;
 775                 count -= retval;
 776         }
 777         *ppos = dst;
 778         free_page((unsigned long) page);
 779         return copied;
 780 }
 781 #endif
 782
 783 static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
 784 {
 785         switch (orig) {
 786         case 0:
 787                 file->f_pos = offset;
 788                 break;
 789         case 1:
 790                 file->f_pos += offset;
 791                 break;
 792         default:
 793                 return -EINVAL;
 794         }
 795         force_successful_syscall_return();
 796         return file->f_pos;
 797 }
 798
 799 static struct file_operations proc_mem_operations = {
 800         .llseek         = mem_lseek,
 801         .read           = mem_read,
 802         .write          = mem_write,
 803         .open           = mem_open,
 804 };
 805
 806 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
 807                                 size_t count, loff_t *ppos)
 808 {
 809         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 810         char buffer[8];
 811         size_t len;
 812         int oom_adjust = task->oomkilladj;
 813         loff_t __ppos = *ppos;
 814
 815         len = sprintf(buffer, "%i\n", oom_adjust);
 816         if (__ppos >= len)
 817                 return 0;
 818         if (count > len-__ppos)
 819                 count = len-__ppos;
 820         if (copy_to_user(buf, buffer + __ppos, count))
 821                 return -EFAULT;
 822         *ppos = __ppos + count;
 823         return count;
 824 }
 825
 826 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 827                                 size_t count, loff_t *ppos)
 828 {
 829         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 830         char buffer[8], *end;
 831         int oom_adjust;
 832
 833         if (!capable(CAP_SYS_RESOURCE))
 834                 return -EPERM;
 835         memset(buffer, 0, 8);
 836         if (count > 6)
 837                 count = 6;
 838         if (copy_from_user(buffer, buf, count))
 839                 return -EFAULT;
 840         oom_adjust = simple_strtol(buffer, &end, 0);
 841         if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
 842                 return -EINVAL;
 843         if (*end == '\n')
 844                 end++;
 845         task->oomkilladj = oom_adjust;
 846         if (end - buffer == 0)
 847                 return -EIO;
 848         return end - buffer;
 849 }
 850
 851 static struct file_operations proc_oom_adjust_operations = {
 852         .read           = oom_adjust_read,
 853         .write          = oom_adjust_write,
 854 };
 855
 856 #ifdef CONFIG_AUDITSYSCALL
 857 #define TMPBUFLEN 21
 858 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
 859                                   size_t count, loff_t *ppos)
 860 {
 861         struct inode * inode = file->f_dentry->d_inode;
 862         struct task_struct *task = proc_task(inode);
 863         ssize_t length;
 864         char tmpbuf[TMPBUFLEN];
 865
 866         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
 867                                 audit_get_loginuid(task->audit_context));
 868         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 869 }
 870
 871 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 872                                    size_t count, loff_t *ppos)
 873 {
 874         struct inode * inode = file->f_dentry->d_inode;
 875         char *page, *tmp;
 876         ssize_t length;
 877         struct task_struct *task = proc_task(inode);
 878         uid_t loginuid;
 879
 880         if (!capable(CAP_AUDIT_CONTROL))
 881                 return -EPERM;
 882
 883         if (current != task)
 884                 return -EPERM;
 885
 886         if (count >= PAGE_SIZE)
 887                 count = PAGE_SIZE - 1;
 888
 889         if (*ppos != 0) {
 890                 /* No partial writes. */
 891                 return -EINVAL;
 892         }
 893         page = (char*)__get_free_page(GFP_USER);
 894         if (!page)
 895                 return -ENOMEM;
 896         length = -EFAULT;
 897         if (copy_from_user(page, buf, count))
 898                 goto out_free_page;
 899
 900         page[count] = '\0';
 901         loginuid = simple_strtoul(page, &tmp, 10);
 902         if (tmp == page) {
 903                 length = -EINVAL;
 904                 goto out_free_page;
 905
 906         }
 907         length = audit_set_loginuid(task, loginuid);
 908         if (likely(length == 0))
 909                 length = count;
 910
 911 out_free_page:
 912         free_page((unsigned long) page);
 913         return length;
 914 }
 915
 916 static struct file_operations proc_loginuid_operations = {
 917         .read           = proc_loginuid_read,
 918         .write          = proc_loginuid_write,
 919 };
 920 #endif
 921
 922 #ifdef CONFIG_SECCOMP
 923 static ssize_t seccomp_read(struct file *file, char __user *buf,
 924                             size_t count, loff_t *ppos)
 925 {
 926         struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
 927         char __buf[20];
 928         loff_t __ppos = *ppos;
 929         size_t len;
 930
 931         /* no need to print the trailing zero, so use only len */
 932         len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
 933         if (__ppos >= len)
 934                 return 0;
 935         if (count > len - __ppos)
 936                 count = len - __ppos;
 937         if (copy_to_user(buf, __buf + __ppos, count))
 938                 return -EFAULT;
 939         *ppos = __ppos + count;
 940         return count;
 941 }
 942
 943 static ssize_t seccomp_write(struct file *file, const char __user *buf,
 944                              size_t count, loff_t *ppos)
 945 {
 946         struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
 947         char __buf[20], *end;
 948         unsigned int seccomp_mode;
 949
 950         /* can set it only once to be even more secure */
 951         if (unlikely(tsk->seccomp.mode))
 952                 return -EPERM;
 953
 954         memset(__buf, 0, sizeof(__buf));
 955         count = min(count, sizeof(__buf) - 1);
 956         if (copy_from_user(__buf, buf, count))
 957                 return -EFAULT;
 958         seccomp_mode = simple_strtoul(__buf, &end, 0);
 959         if (*end == '\n')
 960                 end++;
 961         if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
 962                 tsk->seccomp.mode = seccomp_mode;
 963                 set_tsk_thread_flag(tsk, TIF_SECCOMP);
 964         } else
 965                 return -EINVAL;
 966         if (unlikely(!(end - __buf)))
 967                 return -EIO;
 968         return end - __buf;
 969 }
 970
 971 static struct file_operations proc_seccomp_operations = {
 972         .read           = seccomp_read,
 973         .write          = seccomp_write,
 974 };
 975 #endif /* CONFIG_SECCOMP */
 976
 977 static int proc_check_dentry_visible(struct inode *inode,
 978         struct dentry *dentry, struct vfsmount *mnt)
 979 {
 980         /* Verify that the current process can already see the
 981          * file pointed at by the file descriptor.
 982          * This prevents /proc from being an accidental information leak.
 983          *
 984          * This prevents access to files that are not visible do to
 985          * being on the otherside of a chroot, in a different
 986          * namespace, or are simply process local (like pipes).
 987          */
 988         struct task_struct *task;
 989         struct files_struct *task_files, *files;
 990         int error = -EACCES;
 991
 992         /* See if the the two tasks share a commone set of
 993          * file descriptors.  If so everything is visible.
 994          */
 995         task = proc_task(inode);
 996         if (!task)
 997                 goto out;
 998         files = get_files_struct(current);
 999         task_files = get_files_struct(task);
1000         if (files && task_files && (files == task_files))
1001                 error = 0;
1002         if (task_files)
1003                 put_files_struct(task_files);
1004         if (files)
1005                 put_files_struct(files);
1006         if (!error)
1007                 goto out;
1008
1009         /* If the two tasks don't share a common set of file
1010          * descriptors see if the destination dentry is already
1011          * visible in the current tasks filesystem namespace.
1012          */
1013         error = proc_check_chroot(dentry, mnt);
1014 out:
1015         return error;
1016
1017 }
1018
1019 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1020 {
1021         struct inode *inode = dentry->d_inode;
1022         int error = -EACCES;
1023
1024         /* We don't need a base pointer in the /proc filesystem */
1025         path_release(nd);
1026
1027         if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
1028                 goto out;
1029
1030         error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
1031         nd->last_type = LAST_BIND;
1032         if (error)
1033                 goto out;
1034
1035         /* Only return files this task can already see */
1036         error = proc_check_dentry_visible(inode, nd->dentry, nd->mnt);
1037         if (error)
1038                 path_release(nd);
1039 out:
1040         return ERR_PTR(error);
1041 }
1042
1043 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
1044                             char __user *buffer, int buflen)
1045 {
1046         struct inode * inode;
1047         char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
1048         int len;
1049
1050         if (!tmp)
1051                 return -ENOMEM;
1052
1053         inode = dentry->d_inode;
1054         path = d_path(dentry, mnt, tmp, PAGE_SIZE);
1055         len = PTR_ERR(path);
1056         if (IS_ERR(path))
1057                 goto out;
1058         len = tmp + PAGE_SIZE - 1 - path;
1059
1060         if (len > buflen)
1061                 len = buflen;
1062         if (copy_to_user(buffer, path, len))
1063                 len = -EFAULT;
1064  out:
1065         free_page((unsigned long)tmp);
1066         return len;
1067 }
1068
1069 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1070 {
1071         int error = -EACCES;
1072         struct inode *inode = dentry->d_inode;
1073         struct dentry *de;
1074         struct vfsmount *mnt = NULL;
1075
1076
1077         if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
1078                 goto out;
1079
1080         error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
1081         if (error)
1082                 goto out;
1083
1084         /* Only return files this task can already see */
1085         error = proc_check_dentry_visible(inode, de, mnt);
1086         if (error)
1087                 goto out_put;
1088
1089         error = do_proc_readlink(de, mnt, buffer, buflen);
1090 out_put:
1091         dput(de);
1092         mntput(mnt);
1093 out:
1094         return error;
1095 }
1096
1097 static struct inode_operations proc_pid_link_inode_operations = {
1098         .readlink       = proc_pid_readlink,
1099         .follow_link    = proc_pid_follow_link
1100 };
1101
1102 #define NUMBUF 10
1103
1104 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
1105 {
1106         struct dentry *dentry = filp->f_dentry;
1107         struct inode *inode = 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 = parent_ino(dentry);
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         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1270         inode->i_ino = fake_ino(task->pid, ino);
1271
1272         if (!pid_alive(task))
1273                 goto out_unlock;
1274
1275         /*
1276          * grab the reference to task.
1277          */
1278         get_task_struct(task);
1279         ei->task = task;
1280         inode->i_uid = 0;
1281         inode->i_gid = 0;
1282         if (task_dumpable(task)) {
1283                 inode->i_uid = task->euid;
1284                 inode->i_gid = task->egid;
1285         }
1286         security_task_to_inode(task, inode);
1287
1288 out:
1289         return inode;
1290
1291 out_unlock:
1292         iput(inode);
1293         return NULL;
1294 }
1295
1296 /* dentry stuff */
1297
1298 /*
1299  *      Exceptional case: normally we are not allowed to unhash a busy
1300  * directory. In this case, however, we can do it - no aliasing problems
1301  * due to the way we treat inodes.
1302  *
1303  * Rewrite the inode's ownerships here because the owning task may have
1304  * performed a setuid(), etc.
1305  */
1306 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1307 {
1308         struct inode *inode = dentry->d_inode;
1309         struct task_struct *task = proc_task(inode);
1310         if (pid_alive(task)) {
1311                 if (task_dumpable(task)) {
1312                         inode->i_uid = task->euid;
1313                         inode->i_gid = task->egid;
1314                 } else {
1315                         inode->i_uid = 0;
1316                         inode->i_gid = 0;
1317                 }
1318                 security_task_to_inode(task, inode);
1319                 return 1;
1320         }
1321         d_drop(dentry);
1322         return 0;
1323 }
1324
1325 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1326 {
1327         struct inode *inode = dentry->d_inode;
1328         struct task_struct *task = proc_task(inode);
1329         int fd = proc_fd(inode);
1330         struct files_struct *files;
1331
1332         files = get_files_struct(task);
1333         if (files) {
1334                 rcu_read_lock();
1335                 if (fcheck_files(files, fd)) {
1336                         rcu_read_unlock();
1337                         put_files_struct(files);
1338                         if (task_dumpable(task)) {
1339                                 inode->i_uid = task->euid;
1340                                 inode->i_gid = task->egid;
1341                         } else {
1342                                 inode->i_uid = 0;
1343                                 inode->i_gid = 0;
1344                         }
1345                         security_task_to_inode(task, inode);
1346                         return 1;
1347                 }
1348                 rcu_read_unlock();
1349                 put_files_struct(files);
1350         }
1351         d_drop(dentry);
1352         return 0;
1353 }
1354
1355 static void pid_base_iput(struct dentry *dentry, struct inode *inode)
1356 {
1357         struct task_struct *task = proc_task(inode);
1358         spin_lock(&task->proc_lock);
1359         if (task->proc_dentry == dentry)
1360                 task->proc_dentry = NULL;
1361         spin_unlock(&task->proc_lock);
1362         iput(inode);
1363 }
1364
1365 static int pid_delete_dentry(struct dentry * dentry)
1366 {
1367         /* Is the task we represent dead?
1368          * If so, then don't put the dentry on the lru list,
1369          * kill it immediately.
1370          */
1371         return !pid_alive(proc_task(dentry->d_inode));
1372 }
1373
1374 static struct dentry_operations tid_fd_dentry_operations =
1375 {
1376         .d_revalidate   = tid_fd_revalidate,
1377         .d_delete       = pid_delete_dentry,
1378 };
1379
1380 static struct dentry_operations pid_dentry_operations =
1381 {
1382         .d_revalidate   = pid_revalidate,
1383         .d_delete       = pid_delete_dentry,
1384 };
1385
1386 static struct dentry_operations pid_base_dentry_operations =
1387 {
1388         .d_revalidate   = pid_revalidate,
1389         .d_iput         = pid_base_iput,
1390         .d_delete       = pid_delete_dentry,
1391 };
1392
1393 /* Lookups */
1394
1395 static unsigned name_to_int(struct dentry *dentry)
1396 {
1397         const char *name = dentry->d_name.name;
1398         int len = dentry->d_name.len;
1399         unsigned n = 0;
1400
1401         if (len > 1 && *name == '0')
1402                 goto out;
1403         while (len-- > 0) {
1404                 unsigned c = *name++ - '0';
1405                 if (c > 9)
1406                         goto out;
1407                 if (n >= (~0U-9)/10)
1408                         goto out;
1409                 n *= 10;
1410                 n += c;
1411         }
1412         return n;
1413 out:
1414         return ~0U;
1415 }
1416
1417 /* SMP-safe */
1418 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
1419 {
1420         struct task_struct *task = proc_task(dir);
1421         unsigned fd = name_to_int(dentry);
1422         struct file * file;
1423         struct files_struct * files;
1424         struct inode *inode;
1425         struct proc_inode *ei;
1426
1427         if (fd == ~0U)
1428                 goto out;
1429         if (!pid_alive(task))
1430                 goto out;
1431
1432         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
1433         if (!inode)
1434                 goto out;
1435         ei = PROC_I(inode);
1436         ei->fd = fd;
1437         files = get_files_struct(task);
1438         if (!files)
1439                 goto out_unlock;
1440         inode->i_mode = S_IFLNK;
1441
1442         /*
1443          * We are not taking a ref to the file structure, so we must
1444          * hold ->file_lock.
1445          */
1446         spin_lock(&files->file_lock);
1447         file = fcheck_files(files, fd);
1448         if (!file)
1449                 goto out_unlock2;
1450         if (file->f_mode & 1)
1451                 inode->i_mode |= S_IRUSR | S_IXUSR;
1452         if (file->f_mode & 2)
1453                 inode->i_mode |= S_IWUSR | S_IXUSR;
1454         spin_unlock(&files->file_lock);
1455         put_files_struct(files);
1456         inode->i_op = &proc_pid_link_inode_operations;
1457         inode->i_size = 64;
1458         ei->op.proc_get_link = proc_fd_link;
1459         dentry->d_op = &tid_fd_dentry_operations;
1460         d_add(dentry, inode);
1461         return NULL;
1462
1463 out_unlock2:
1464         spin_unlock(&files->file_lock);
1465         put_files_struct(files);
1466 out_unlock:
1467         iput(inode);
1468 out:
1469         return ERR_PTR(-ENOENT);
1470 }
1471
1472 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
1473 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
1474 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat);
1475
1476 static struct file_operations proc_fd_operations = {
1477         .read           = generic_read_dir,
1478         .readdir        = proc_readfd,
1479 };
1480
1481 static struct file_operations proc_task_operations = {
1482         .read           = generic_read_dir,
1483         .readdir        = proc_task_readdir,
1484 };
1485
1486 /*
1487  * proc directories can do almost nothing..
1488  */
1489 static struct inode_operations proc_fd_inode_operations = {
1490         .lookup         = proc_lookupfd,
1491 };
1492
1493 static struct inode_operations proc_task_inode_operations = {
1494         .lookup         = proc_task_lookup,
1495         .getattr        = proc_task_getattr,
1496 };
1497
1498 #ifdef CONFIG_SECURITY
1499 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
1500                                   size_t count, loff_t *ppos)
1501 {
1502         struct inode * inode = file->f_dentry->d_inode;
1503         unsigned long page;
1504         ssize_t length;
1505         struct task_struct *task = proc_task(inode);
1506
1507         if (count > PAGE_SIZE)
1508                 count = PAGE_SIZE;
1509         if (!(page = __get_free_page(GFP_KERNEL)))
1510                 return -ENOMEM;
1511
1512         length = security_getprocattr(task,
1513                                       (char*)file->f_dentry->d_name.name,
1514                                       (void*)page, count);
1515         if (length >= 0)
1516                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
1517         free_page(page);
1518         return length;
1519 }
1520
1521 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
1522                                    size_t count, loff_t *ppos)
1523 {
1524         struct inode * inode = file->f_dentry->d_inode;
1525         char *page;
1526         ssize_t length;
1527         struct task_struct *task = proc_task(inode);
1528
1529         if (count > PAGE_SIZE)
1530                 count = PAGE_SIZE;
1531         if (*ppos != 0) {
1532                 /* No partial writes. */
1533                 return -EINVAL;
1534         }
1535         page = (char*)__get_free_page(GFP_USER);
1536         if (!page)
1537                 return -ENOMEM;
1538         length = -EFAULT;
1539         if (copy_from_user(page, buf, count))
1540                 goto out;
1541
1542         length = security_setprocattr(task,
1543                                       (char*)file->f_dentry->d_name.name,
1544                                       (void*)page, count);
1545 out:
1546         free_page((unsigned long) page);
1547         return length;
1548 }
1549
1550 static struct file_operations proc_pid_attr_operations = {
1551         .read           = proc_pid_attr_read,
1552         .write          = proc_pid_attr_write,
1553 };
1554
1555 static struct file_operations proc_tid_attr_operations;
1556 static struct inode_operations proc_tid_attr_inode_operations;
1557 static struct file_operations proc_tgid_attr_operations;
1558 static struct inode_operations proc_tgid_attr_inode_operations;
1559 #endif
1560
1561 static int get_tid_list(int index, unsigned int *tids, struct inode *dir);
1562
1563 /* SMP-safe */
1564 static struct dentry *proc_pident_lookup(struct inode *dir,
1565                                          struct dentry *dentry,
1566                                          struct pid_entry *ents)
1567 {
1568         struct inode *inode;
1569         int error;
1570         struct task_struct *task = proc_task(dir);
1571         struct pid_entry *p;
1572         struct proc_inode *ei;
1573
1574         error = -ENOENT;
1575         inode = NULL;
1576
1577         if (!pid_alive(task))
1578                 goto out;
1579
1580         for (p = ents; p->name; p++) {
1581                 if (p->len != dentry->d_name.len)
1582                         continue;
1583                 if (!memcmp(dentry->d_name.name, p->name, p->len))
1584                         break;
1585         }
1586         if (!p->name)
1587                 goto out;
1588
1589         error = -EINVAL;
1590         inode = proc_pid_make_inode(dir->i_sb, task, p->type);
1591         if (!inode)
1592                 goto out;
1593
1594         ei = PROC_I(inode);
1595         inode->i_mode = p->mode;
1596         /*
1597          * Yes, it does not scale. And it should not. Don't add
1598          * new entries into /proc/<tgid>/ without very good reasons.
1599          */
1600         switch(p->type) {
1601                 case PROC_TGID_TASK:
1602                         inode->i_nlink = 2;
1603                         inode->i_op = &proc_task_inode_operations;
1604                         inode->i_fop = &proc_task_operations;
1605                         break;
1606                 case PROC_TID_FD:
1607                 case PROC_TGID_FD:
1608                         inode->i_nlink = 2;
1609                         inode->i_op = &proc_fd_inode_operations;
1610                         inode->i_fop = &proc_fd_operations;
1611                         break;
1612                 case PROC_TID_EXE:
1613                 case PROC_TGID_EXE:
1614                         inode->i_op = &proc_pid_link_inode_operations;
1615                         ei->op.proc_get_link = proc_exe_link;
1616                         break;
1617                 case PROC_TID_CWD:
1618                 case PROC_TGID_CWD:
1619                         inode->i_op = &proc_pid_link_inode_operations;
1620                         ei->op.proc_get_link = proc_cwd_link;
1621                         break;
1622                 case PROC_TID_ROOT:
1623                 case PROC_TGID_ROOT:
1624                         inode->i_op = &proc_pid_link_inode_operations;
1625                         ei->op.proc_get_link = proc_root_link;
1626                         break;
1627                 case PROC_TID_ENVIRON:
1628                 case PROC_TGID_ENVIRON:
1629                         inode->i_fop = &proc_info_file_operations;
1630                         ei->op.proc_read = proc_pid_environ;
1631                         break;
1632                 case PROC_TID_AUXV:
1633                 case PROC_TGID_AUXV:
1634                         inode->i_fop = &proc_info_file_operations;
1635                         ei->op.proc_read = proc_pid_auxv;
1636                         break;
1637                 case PROC_TID_STATUS:
1638                 case PROC_TGID_STATUS:
1639                         inode->i_fop = &proc_info_file_operations;
1640                         ei->op.proc_read = proc_pid_status;
1641                         break;
1642                 case PROC_TID_STAT:
1643                         inode->i_fop = &proc_info_file_operations;
1644                         ei->op.proc_read = proc_tid_stat;
1645                         break;
1646                 case PROC_TGID_STAT:
1647                         inode->i_fop = &proc_info_file_operations;
1648                         ei->op.proc_read = proc_tgid_stat;
1649                         break;
1650                 case PROC_TID_CMDLINE:
1651                 case PROC_TGID_CMDLINE:
1652                         inode->i_fop = &proc_info_file_operations;
1653                         ei->op.proc_read = proc_pid_cmdline;
1654                         break;
1655                 case PROC_TID_STATM:
1656                 case PROC_TGID_STATM:
1657                         inode->i_fop = &proc_info_file_operations;
1658                         ei->op.proc_read = proc_pid_statm;
1659                         break;
1660                 case PROC_TID_MAPS:
1661                 case PROC_TGID_MAPS:
1662                         inode->i_fop = &proc_maps_operations;
1663                         break;
1664 #ifdef CONFIG_NUMA
1665                 case PROC_TID_NUMA_MAPS:
1666                 case PROC_TGID_NUMA_MAPS:
1667                         inode->i_fop = &proc_numa_maps_operations;
1668                         break;
1669 #endif
1670                 case PROC_TID_MEM:
1671                 case PROC_TGID_MEM:
1672                         inode->i_fop = &proc_mem_operations;
1673                         break;
1674 #ifdef CONFIG_SECCOMP
1675                 case PROC_TID_SECCOMP:
1676                 case PROC_TGID_SECCOMP:
1677                         inode->i_fop = &proc_seccomp_operations;
1678                         break;
1679 #endif /* CONFIG_SECCOMP */
1680                 case PROC_TID_MOUNTS:
1681                 case PROC_TGID_MOUNTS:
1682                         inode->i_fop = &proc_mounts_operations;
1683                         break;
1684 #ifdef CONFIG_MMU
1685                 case PROC_TID_SMAPS:
1686                 case PROC_TGID_SMAPS:
1687                         inode->i_fop = &proc_smaps_operations;
1688                         break;
1689 #endif
1690                 case PROC_TID_MOUNTSTATS:
1691                 case PROC_TGID_MOUNTSTATS:
1692                         inode->i_fop = &proc_mountstats_operations;
1693                         break;
1694 #ifdef CONFIG_SECURITY
1695                 case PROC_TID_ATTR:
1696                         inode->i_nlink = 2;
1697                         inode->i_op = &proc_tid_attr_inode_operations;
1698                         inode->i_fop = &proc_tid_attr_operations;
1699                         break;
1700                 case PROC_TGID_ATTR:
1701                         inode->i_nlink = 2;
1702                         inode->i_op = &proc_tgid_attr_inode_operations;
1703                         inode->i_fop = &proc_tgid_attr_operations;
1704                         break;
1705                 case PROC_TID_ATTR_CURRENT:
1706                 case PROC_TGID_ATTR_CURRENT:
1707                 case PROC_TID_ATTR_PREV:
1708                 case PROC_TGID_ATTR_PREV:
1709                 case PROC_TID_ATTR_EXEC:
1710                 case PROC_TGID_ATTR_EXEC:
1711                 case PROC_TID_ATTR_FSCREATE:
1712                 case PROC_TGID_ATTR_FSCREATE:
1713                 case PROC_TID_ATTR_KEYCREATE:
1714                 case PROC_TGID_ATTR_KEYCREATE:
1715                         inode->i_fop = &proc_pid_attr_operations;
1716                         break;
1717 #endif
1718 #ifdef CONFIG_KALLSYMS
1719                 case PROC_TID_WCHAN:
1720                 case PROC_TGID_WCHAN:
1721                         inode->i_fop = &proc_info_file_operations;
1722                         ei->op.proc_read = proc_pid_wchan;
1723                         break;
1724 #endif
1725 #ifdef CONFIG_SCHEDSTATS
1726                 case PROC_TID_SCHEDSTAT:
1727                 case PROC_TGID_SCHEDSTAT:
1728                         inode->i_fop = &proc_info_file_operations;
1729                         ei->op.proc_read = proc_pid_schedstat;
1730                         break;
1731 #endif
1732 #ifdef CONFIG_CPUSETS
1733                 case PROC_TID_CPUSET:
1734                 case PROC_TGID_CPUSET:
1735                         inode->i_fop = &proc_cpuset_operations;
1736                         break;
1737 #endif
1738                 case PROC_TID_OOM_SCORE:
1739                 case PROC_TGID_OOM_SCORE:
1740                         inode->i_fop = &proc_info_file_operations;
1741                         ei->op.proc_read = proc_oom_score;
1742                         break;
1743                 case PROC_TID_OOM_ADJUST:
1744                 case PROC_TGID_OOM_ADJUST:
1745                         inode->i_fop = &proc_oom_adjust_operations;
1746                         break;
1747 #ifdef CONFIG_AUDITSYSCALL
1748                 case PROC_TID_LOGINUID:
1749                 case PROC_TGID_LOGINUID:
1750                         inode->i_fop = &proc_loginuid_operations;
1751                         break;
1752 #endif
1753                 default:
1754                         printk("procfs: impossible type (%d)",p->type);
1755                         iput(inode);
1756                         return ERR_PTR(-EINVAL);
1757         }
1758         dentry->d_op = &pid_dentry_operations;
1759         d_add(dentry, inode);
1760         return NULL;
1761
1762 out:
1763         return ERR_PTR(error);
1764 }
1765
1766 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1767         return proc_pident_lookup(dir, dentry, tgid_base_stuff);
1768 }
1769
1770 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1771         return proc_pident_lookup(dir, dentry, tid_base_stuff);
1772 }
1773
1774 static struct file_operations proc_tgid_base_operations = {
1775         .read           = generic_read_dir,
1776         .readdir        = proc_tgid_base_readdir,
1777 };
1778
1779 static struct file_operations proc_tid_base_operations = {
1780         .read           = generic_read_dir,
1781         .readdir        = proc_tid_base_readdir,
1782 };
1783
1784 static struct inode_operations proc_tgid_base_inode_operations = {
1785         .lookup         = proc_tgid_base_lookup,
1786 };
1787
1788 static struct inode_operations proc_tid_base_inode_operations = {
1789         .lookup         = proc_tid_base_lookup,
1790 };
1791
1792 #ifdef CONFIG_SECURITY
1793 static int proc_tgid_attr_readdir(struct file * filp,
1794                              void * dirent, filldir_t filldir)
1795 {
1796         return proc_pident_readdir(filp,dirent,filldir,
1797                                    tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
1798 }
1799
1800 static int proc_tid_attr_readdir(struct file * filp,
1801                              void * dirent, filldir_t filldir)
1802 {
1803         return proc_pident_readdir(filp,dirent,filldir,
1804                                    tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
1805 }
1806
1807 static struct file_operations proc_tgid_attr_operations = {
1808         .read           = generic_read_dir,
1809         .readdir        = proc_tgid_attr_readdir,
1810 };
1811
1812 static struct file_operations proc_tid_attr_operations = {
1813         .read           = generic_read_dir,
1814         .readdir        = proc_tid_attr_readdir,
1815 };
1816
1817 static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
1818                                 struct dentry *dentry, struct nameidata *nd)
1819 {
1820         return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
1821 }
1822
1823 static struct dentry *proc_tid_attr_lookup(struct inode *dir,
1824                                 struct dentry *dentry, struct nameidata *nd)
1825 {
1826         return proc_pident_lookup(dir, dentry, tid_attr_stuff);
1827 }
1828
1829 static struct inode_operations proc_tgid_attr_inode_operations = {
1830         .lookup         = proc_tgid_attr_lookup,
1831 };
1832
1833 static struct inode_operations proc_tid_attr_inode_operations = {
1834         .lookup         = proc_tid_attr_lookup,
1835 };
1836 #endif
1837
1838 /*
1839  * /proc/self:
1840  */
1841 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
1842                               int buflen)
1843 {
1844         char tmp[30];
1845         sprintf(tmp, "%d", current->tgid);
1846         return vfs_readlink(dentry,buffer,buflen,tmp);
1847 }
1848
1849 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
1850 {
1851         char tmp[30];
1852         sprintf(tmp, "%d", current->tgid);
1853         return ERR_PTR(vfs_follow_link(nd,tmp));
1854 }
1855
1856 static struct inode_operations proc_self_inode_operations = {
1857         .readlink       = proc_self_readlink,
1858         .follow_link    = proc_self_follow_link,
1859 };
1860
1861 /**
1862  * proc_pid_unhash -  Unhash /proc/@pid entry from the dcache.
1863  * @p: task that should be flushed.
1864  *
1865  * Drops the /proc/@pid dcache entry from the hash chains.
1866  *
1867  * Dropping /proc/@pid entries and detach_pid must be synchroneous,
1868  * otherwise e.g. /proc/@pid/exe might point to the wrong executable,
1869  * if the pid value is immediately reused. This is enforced by
1870  * - caller must acquire spin_lock(p->proc_lock)
1871  * - must be called before detach_pid()
1872  * - proc_pid_lookup acquires proc_lock, and checks that
1873  *   the target is not dead by looking at the attach count
1874  *   of PIDTYPE_PID.
1875  */
1876
1877 struct dentry *proc_pid_unhash(struct task_struct *p)
1878 {
1879         struct dentry *proc_dentry;
1880
1881         proc_dentry = p->proc_dentry;
1882         if (proc_dentry != NULL) {
1883
1884                 spin_lock(&dcache_lock);
1885                 spin_lock(&proc_dentry->d_lock);
1886                 if (!d_unhashed(proc_dentry)) {
1887                         dget_locked(proc_dentry);
1888                         __d_drop(proc_dentry);
1889                         spin_unlock(&proc_dentry->d_lock);
1890                 } else {
1891                         spin_unlock(&proc_dentry->d_lock);
1892                         proc_dentry = NULL;
1893                 }
1894                 spin_unlock(&dcache_lock);
1895         }
1896         return proc_dentry;
1897 }
1898
1899 /**
1900  * proc_pid_flush - recover memory used by stale /proc/@pid/x entries
1901  * @proc_dentry: directoy to prune.
1902  *
1903  * Shrink the /proc directory that was used by the just killed thread.
1904  */
1905
1906 void proc_pid_flush(struct dentry *proc_dentry)
1907 {
1908         might_sleep();
1909         if(proc_dentry != NULL) {
1910                 shrink_dcache_parent(proc_dentry);
1911                 dput(proc_dentry);
1912         }
1913 }
1914
1915 /* SMP-safe */
1916 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1917 {
1918         struct task_struct *task;
1919         struct inode *inode;
1920         struct proc_inode *ei;
1921         unsigned tgid;
1922         int died;
1923
1924         if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
1925                 inode = new_inode(dir->i_sb);
1926                 if (!inode)
1927                         return ERR_PTR(-ENOMEM);
1928                 ei = PROC_I(inode);
1929                 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1930                 inode->i_ino = fake_ino(0, PROC_TGID_INO);
1931                 ei->pde = NULL;
1932                 inode->i_mode = S_IFLNK|S_IRWXUGO;
1933                 inode->i_uid = inode->i_gid = 0;
1934                 inode->i_size = 64;
1935                 inode->i_op = &proc_self_inode_operations;
1936                 d_add(dentry, inode);
1937                 return NULL;
1938         }
1939         tgid = name_to_int(dentry);
1940         if (tgid == ~0U)
1941                 goto out;
1942
1943         read_lock(&tasklist_lock);
1944         task = find_task_by_pid(tgid);
1945         if (task)
1946                 get_task_struct(task);
1947         read_unlock(&tasklist_lock);
1948         if (!task)
1949                 goto out;
1950
1951         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
1952
1953
1954         if (!inode) {
1955                 put_task_struct(task);
1956                 goto out;
1957         }
1958         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
1959         inode->i_op = &proc_tgid_base_inode_operations;
1960         inode->i_fop = &proc_tgid_base_operations;
1961         inode->i_flags|=S_IMMUTABLE;
1962 #ifdef CONFIG_SECURITY
1963         inode->i_nlink = 5;
1964 #else
1965         inode->i_nlink = 4;
1966 #endif
1967
1968         dentry->d_op = &pid_base_dentry_operations;
1969
1970         died = 0;
1971         d_add(dentry, inode);
1972         spin_lock(&task->proc_lock);
1973         task->proc_dentry = dentry;
1974         if (!pid_alive(task)) {
1975                 dentry = proc_pid_unhash(task);
1976                 died = 1;
1977         }
1978         spin_unlock(&task->proc_lock);
1979
1980         put_task_struct(task);
1981         if (died) {
1982                 proc_pid_flush(dentry);
1983                 goto out;
1984         }
1985         return NULL;
1986 out:
1987         return ERR_PTR(-ENOENT);
1988 }
1989
1990 /* SMP-safe */
1991 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1992 {
1993         struct task_struct *task;
1994         struct task_struct *leader = proc_task(dir);
1995         struct inode *inode;
1996         unsigned tid;
1997
1998         tid = name_to_int(dentry);
1999         if (tid == ~0U)
2000                 goto out;
2001
2002         read_lock(&tasklist_lock);
2003         task = find_task_by_pid(tid);
2004         if (task)
2005                 get_task_struct(task);
2006         read_unlock(&tasklist_lock);
2007         if (!task)
2008                 goto out;
2009         if (leader->tgid != task->tgid)
2010                 goto out_drop_task;
2011
2012         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);
2013
2014
2015         if (!inode)
2016                 goto out_drop_task;
2017         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2018         inode->i_op = &proc_tid_base_inode_operations;
2019         inode->i_fop = &proc_tid_base_operations;
2020         inode->i_flags|=S_IMMUTABLE;
2021 #ifdef CONFIG_SECURITY
2022         inode->i_nlink = 4;
2023 #else
2024         inode->i_nlink = 3;
2025 #endif
2026
2027         dentry->d_op = &pid_base_dentry_operations;
2028
2029         d_add(dentry, inode);
2030
2031         put_task_struct(task);
2032         return NULL;
2033 out_drop_task:
2034         put_task_struct(task);
2035 out:
2036         return ERR_PTR(-ENOENT);
2037 }
2038
2039 #define PROC_NUMBUF 10
2040 #define PROC_MAXPIDS 20
2041
2042 /*
2043  * Get a few tgid's to return for filldir - we need to hold the
2044  * tasklist lock while doing this, and we must release it before
2045  * we actually do the filldir itself, so we use a temp buffer..
2046  */
2047 static int get_tgid_list(int index, unsigned long version, unsigned int *tgids)
2048 {
2049         struct task_struct *p;
2050         int nr_tgids = 0;
2051
2052         index--;
2053         read_lock(&tasklist_lock);
2054         p = NULL;
2055         if (version) {
2056                 p = find_task_by_pid(version);
2057                 if (p && !thread_group_leader(p))
2058                         p = NULL;
2059         }
2060
2061         if (p)
2062                 index = 0;
2063         else
2064                 p = next_task(&init_task);
2065
2066         for ( ; p != &init_task; p = next_task(p)) {
2067                 int tgid = p->pid;
2068                 if (!pid_alive(p))
2069                         continue;
2070                 if (--index >= 0)
2071                         continue;
2072                 tgids[nr_tgids] = tgid;
2073                 nr_tgids++;
2074                 if (nr_tgids >= PROC_MAXPIDS)
2075                         break;
2076         }
2077         read_unlock(&tasklist_lock);
2078         return nr_tgids;
2079 }
2080
2081 /*
2082  * Get a few tid's to return for filldir - we need to hold the
2083  * tasklist lock while doing this, and we must release it before
2084  * we actually do the filldir itself, so we use a temp buffer..
2085  */
2086 static int get_tid_list(int index, unsigned int *tids, struct inode *dir)
2087 {
2088         struct task_struct *leader_task = proc_task(dir);
2089         struct task_struct *task = leader_task;
2090         int nr_tids = 0;
2091
2092         index -= 2;
2093         read_lock(&tasklist_lock);
2094         /*
2095          * The starting point task (leader_task) might be an already
2096          * unlinked task, which cannot be used to access the task-list
2097          * via next_thread().
2098          */
2099         if (pid_alive(task)) do {
2100                 int tid = task->pid;
2101
2102                 if (--index >= 0)
2103                         continue;
2104                 if (tids != NULL)
2105                         tids[nr_tids] = tid;
2106                 nr_tids++;
2107                 if (nr_tids >= PROC_MAXPIDS)
2108                         break;
2109         } while ((task = next_thread(task)) != leader_task);
2110         read_unlock(&tasklist_lock);
2111         return nr_tids;
2112 }
2113
2114 /* for the /proc/ directory itself, after non-process stuff has been done */
2115 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2116 {
2117         unsigned int tgid_array[PROC_MAXPIDS];
2118         char buf[PROC_NUMBUF];
2119         unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2120         unsigned int nr_tgids, i;
2121         int next_tgid;
2122
2123         if (!nr) {
2124                 ino_t ino = fake_ino(0,PROC_TGID_INO);
2125                 if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
2126                         return 0;
2127                 filp->f_pos++;
2128                 nr++;
2129         }
2130
2131         /* f_version caches the tgid value that the last readdir call couldn't
2132          * return. lseek aka telldir automagically resets f_version to 0.
2133          */
2134         next_tgid = filp->f_version;
2135         filp->f_version = 0;
2136         for (;;) {
2137                 nr_tgids = get_tgid_list(nr, next_tgid, tgid_array);
2138                 if (!nr_tgids) {
2139                         /* no more entries ! */
2140                         break;
2141                 }
2142                 next_tgid = 0;
2143
2144                 /* do not use the last found pid, reserve it for next_tgid */
2145                 if (nr_tgids == PROC_MAXPIDS) {
2146                         nr_tgids--;
2147                         next_tgid = tgid_array[nr_tgids];
2148                 }
2149
2150                 for (i=0;i<nr_tgids;i++) {
2151                         int tgid = tgid_array[i];
2152                         ino_t ino = fake_ino(tgid,PROC_TGID_INO);
2153                         unsigned long j = PROC_NUMBUF;
2154
2155                         do
2156                                 buf[--j] = '0' + (tgid % 10);
2157                         while ((tgid /= 10) != 0);
2158
2159                         if (filldir(dirent, buf+j, PROC_NUMBUF-j, filp->f_pos, ino, DT_DIR) < 0) {
2160                                 /* returning this tgid failed, save it as the first
2161                                  * pid for the next readir call */
2162                                 filp->f_version = tgid_array[i];
2163                                 goto out;
2164                         }
2165                         filp->f_pos++;
2166                         nr++;
2167                 }
2168         }
2169 out:
2170         return 0;
2171 }
2172
2173 /* for the /proc/TGID/task/ directories */
2174 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
2175 {
2176         unsigned int tid_array[PROC_MAXPIDS];
2177         char buf[PROC_NUMBUF];
2178         unsigned int nr_tids, i;
2179         struct dentry *dentry = filp->f_dentry;
2180         struct inode *inode = dentry->d_inode;
2181         int retval = -ENOENT;
2182         ino_t ino;
2183         unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
2184
2185         if (!pid_alive(proc_task(inode)))
2186                 goto out;
2187         retval = 0;
2188
2189         switch (pos) {
2190         case 0:
2191                 ino = inode->i_ino;
2192                 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
2193                         goto out;
2194                 pos++;
2195                 /* fall through */
2196         case 1:
2197                 ino = parent_ino(dentry);
2198                 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
2199                         goto out;
2200                 pos++;
2201                 /* fall through */
2202         }
2203
2204         nr_tids = get_tid_list(pos, tid_array, inode);
2205
2206         for (i = 0; i < nr_tids; i++) {
2207                 unsigned long j = PROC_NUMBUF;
2208                 int tid = tid_array[i];
2209
2210                 ino = fake_ino(tid,PROC_TID_INO);
2211
2212                 do
2213                         buf[--j] = '0' + (tid % 10);
2214                 while ((tid /= 10) != 0);
2215
2216                 if (filldir(dirent, buf+j, PROC_NUMBUF-j, pos, ino, DT_DIR) < 0)
2217                         break;
2218                 pos++;
2219         }
2220 out:
2221         filp->f_pos = pos;
2222         return retval;
2223 }
2224
2225 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
2226 {
2227         struct inode *inode = dentry->d_inode;
2228         struct task_struct *p = proc_task(inode);
2229         generic_fillattr(inode, stat);
2230
2231         if (pid_alive(p)) {
2232                 task_lock(p);
2233                 if (p->signal)
2234                         stat->nlink += atomic_read(&p->signal->count);
2235                 task_unlock(p);
2236         }
2237
2238         return 0;
2239 }