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/errno.h>
  53 #include <linux/time.h>
  54 #include <linux/proc_fs.h>
  55 #include <linux/stat.h>
  56 #include <linux/init.h>
  57 #include <linux/capability.h>
  58 #include <linux/file.h>
  59 #include <linux/string.h>
  60 #include <linux/seq_file.h>
  61 #include <linux/namei.h>
  62 #include <linux/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 <linux/poll.h>
  74 #include "internal.h"
  75
  76 /* NOTE:
  77  *      Implementing inode permission operations in /proc is almost
  78  *      certainly an error.  Permission checks need to happen during
  79  *      each system call not at open time.  The reason is that most of
  80  *      what we wish to check for permissions in /proc varies at runtime.
  81  *
  82  *      The classic example of a problem is opening file descriptors
  83  *      in /proc for a task before it execs a suid executable.
  84  */
  85
  86 /*
  87  * For hysterical raisins we keep the same inumbers as in the old procfs.
  88  * Feel free to change the macro below - just keep the range distinct from
  89  * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
  90  * As soon as we'll get a separate superblock we will be able to forget
  91  * about magical ranges too.
  92  */
  93
  94 #define fake_ino(pid,ino) (((pid)<<16)|(ino))
  95
  96 enum pid_directory_inos {
  97         PROC_TGID_INO = 2,
  98         PROC_TGID_TASK,
  99         PROC_TGID_STATUS,
 100         PROC_TGID_MEM,
 101 #ifdef CONFIG_SECCOMP
 102         PROC_TGID_SECCOMP,
 103 #endif
 104         PROC_TGID_CWD,
 105         PROC_TGID_ROOT,
 106         PROC_TGID_EXE,
 107         PROC_TGID_FD,
 108         PROC_TGID_ENVIRON,
 109         PROC_TGID_AUXV,
 110         PROC_TGID_CMDLINE,
 111         PROC_TGID_STAT,
 112         PROC_TGID_STATM,
 113         PROC_TGID_MAPS,
 114         PROC_TGID_NUMA_MAPS,
 115         PROC_TGID_MOUNTS,
 116         PROC_TGID_MOUNTSTATS,
 117         PROC_TGID_WCHAN,
 118 #ifdef CONFIG_MMU
 119         PROC_TGID_SMAPS,
 120 #endif
 121 #ifdef CONFIG_SCHEDSTATS
 122         PROC_TGID_SCHEDSTAT,
 123 #endif
 124 #ifdef CONFIG_CPUSETS
 125         PROC_TGID_CPUSET,
 126 #endif
 127 #ifdef CONFIG_SECURITY
 128         PROC_TGID_ATTR,
 129         PROC_TGID_ATTR_CURRENT,
 130         PROC_TGID_ATTR_PREV,
 131         PROC_TGID_ATTR_EXEC,
 132         PROC_TGID_ATTR_FSCREATE,
 133         PROC_TGID_ATTR_KEYCREATE,
 134         PROC_TGID_ATTR_SOCKCREATE,
 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         PROC_TID_ATTR_SOCKCREATE,
 178 #endif
 179 #ifdef CONFIG_AUDITSYSCALL
 180         PROC_TID_LOGINUID,
 181 #endif
 182         PROC_TID_OOM_SCORE,
 183         PROC_TID_OOM_ADJUST,
 184
 185         /* Add new entries before this */
 186         PROC_TID_FD_DIR = 0x8000,       /* 0x8000-0xffff */
 187 };
 188
 189 /* Worst case buffer size needed for holding an integer. */
 190 #define PROC_NUMBUF 10
 191
 192 struct pid_entry {
 193         int type;
 194         int len;
 195         char *name;
 196         mode_t mode;
 197 };
 198
 199 #define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}
 200
 201 static struct pid_entry tgid_base_stuff[] = {
 202         E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
 203         E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
 204         E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
 205         E(PROC_TGID_AUXV,      "auxv",    S_IFREG|S_IRUSR),
 206         E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
 207         E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
 208         E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
 209         E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
 210         E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
 211 #ifdef CONFIG_NUMA
 212         E(PROC_TGID_NUMA_MAPS, "numa_maps", S_IFREG|S_IRUGO),
 213 #endif
 214         E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 215 #ifdef CONFIG_SECCOMP
 216         E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
 217 #endif
 218         E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
 219         E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
 220         E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
 221         E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
 222         E(PROC_TGID_MOUNTSTATS, "mountstats", S_IFREG|S_IRUSR),
 223 #ifdef CONFIG_MMU
 224         E(PROC_TGID_SMAPS,     "smaps",   S_IFREG|S_IRUGO),
 225 #endif
 226 #ifdef CONFIG_SECURITY
 227         E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
 228 #endif
 229 #ifdef CONFIG_KALLSYMS
 230         E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
 231 #endif
 232 #ifdef CONFIG_SCHEDSTATS
 233         E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
 234 #endif
 235 #ifdef CONFIG_CPUSETS
 236         E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
 237 #endif
 238         E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
 239         E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
 240 #ifdef CONFIG_AUDITSYSCALL
 241         E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 242 #endif
 243         {0,0,NULL,0}
 244 };
 245 static struct pid_entry tid_base_stuff[] = {
 246         E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
 247         E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
 248         E(PROC_TID_AUXV,       "auxv",    S_IFREG|S_IRUSR),
 249         E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
 250         E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
 251         E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
 252         E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
 253         E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
 254 #ifdef CONFIG_NUMA
 255         E(PROC_TID_NUMA_MAPS,  "numa_maps",    S_IFREG|S_IRUGO),
 256 #endif
 257         E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 258 #ifdef CONFIG_SECCOMP
 259         E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
 260 #endif
 261         E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
 262         E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
 263         E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
 264         E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
 265 #ifdef CONFIG_MMU
 266         E(PROC_TID_SMAPS,      "smaps",   S_IFREG|S_IRUGO),
 267 #endif
 268 #ifdef CONFIG_SECURITY
 269         E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
 270 #endif
 271 #ifdef CONFIG_KALLSYMS
 272         E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
 273 #endif
 274 #ifdef CONFIG_SCHEDSTATS
 275         E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
 276 #endif
 277 #ifdef CONFIG_CPUSETS
 278         E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
 279 #endif
 280         E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
 281         E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
 282 #ifdef CONFIG_AUDITSYSCALL
 283         E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 284 #endif
 285         {0,0,NULL,0}
 286 };
 287
 288 #ifdef CONFIG_SECURITY
 289 static struct pid_entry tgid_attr_stuff[] = {
 290         E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
 291         E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
 292         E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
 293         E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 294         E(PROC_TGID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
 295         E(PROC_TGID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO),
 296         {0,0,NULL,0}
 297 };
 298 static struct pid_entry tid_attr_stuff[] = {
 299         E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
 300         E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
 301         E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
 302         E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 303         E(PROC_TID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
 304         E(PROC_TID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO),
 305         {0,0,NULL,0}
 306 };
 307 #endif
 308
 309 #undef E
 310
 311 static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 312 {
 313         struct task_struct *task = get_proc_task(inode);
 314         struct files_struct *files = NULL;
 315         struct file *file;
 316         int fd = proc_fd(inode);
 317
 318         if (task) {
 319                 files = get_files_struct(task);
 320                 put_task_struct(task);
 321         }
 322         if (files) {
 323                 /*
 324                  * We are not taking a ref to the file structure, so we must
 325                  * hold ->file_lock.
 326                  */
 327                 spin_lock(&files->file_lock);
 328                 file = fcheck_files(files, fd);
 329                 if (file) {
 330                         *mnt = mntget(file->f_vfsmnt);
 331                         *dentry = dget(file->f_dentry);
 332                         spin_unlock(&files->file_lock);
 333                         put_files_struct(files);
 334                         return 0;
 335                 }
 336                 spin_unlock(&files->file_lock);
 337                 put_files_struct(files);
 338         }
 339         return -ENOENT;
 340 }
 341
 342 static struct fs_struct *get_fs_struct(struct task_struct *task)
 343 {
 344         struct fs_struct *fs;
 345         task_lock(task);
 346         fs = task->fs;
 347         if(fs)
 348                 atomic_inc(&fs->count);
 349         task_unlock(task);
 350         return fs;
 351 }
 352
 353 static int get_nr_threads(struct task_struct *tsk)
 354 {
 355         /* Must be called with the rcu_read_lock held */
 356         unsigned long flags;
 357         int count = 0;
 358
 359         if (lock_task_sighand(tsk, &flags)) {
 360                 count = atomic_read(&tsk->signal->count);
 361                 unlock_task_sighand(tsk, &flags);
 362         }
 363         return count;
 364 }
 365
 366 static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 367 {
 368         struct task_struct *task = get_proc_task(inode);
 369         struct fs_struct *fs = NULL;
 370         int result = -ENOENT;
 371
 372         if (task) {
 373                 fs = get_fs_struct(task);
 374                 put_task_struct(task);
 375         }
 376         if (fs) {
 377                 read_lock(&fs->lock);
 378                 *mnt = mntget(fs->pwdmnt);
 379                 *dentry = dget(fs->pwd);
 380                 read_unlock(&fs->lock);
 381                 result = 0;
 382                 put_fs_struct(fs);
 383         }
 384         return result;
 385 }
 386
 387 static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 388 {
 389         struct task_struct *task = get_proc_task(inode);
 390         struct fs_struct *fs = NULL;
 391         int result = -ENOENT;
 392
 393         if (task) {
 394                 fs = get_fs_struct(task);
 395                 put_task_struct(task);
 396         }
 397         if (fs) {
 398                 read_lock(&fs->lock);
 399                 *mnt = mntget(fs->rootmnt);
 400                 *dentry = dget(fs->root);
 401                 read_unlock(&fs->lock);
 402                 result = 0;
 403                 put_fs_struct(fs);
 404         }
 405         return result;
 406 }
 407
 408 #define MAY_PTRACE(task) \
 409         (task == current || \
 410         (task->parent == current && \
 411         (task->ptrace & PT_PTRACED) && \
 412          (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
 413          security_ptrace(current,task) == 0))
 414
 415 static int proc_pid_environ(struct task_struct *task, char * buffer)
 416 {
 417         int res = 0;
 418         struct mm_struct *mm = get_task_mm(task);
 419         if (mm) {
 420                 unsigned int len = mm->env_end - mm->env_start;
 421                 if (len > PAGE_SIZE)
 422                         len = PAGE_SIZE;
 423                 res = access_process_vm(task, mm->env_start, buffer, len, 0);
 424                 if (!ptrace_may_attach(task))
 425                         res = -ESRCH;
 426                 mmput(mm);
 427         }
 428         return res;
 429 }
 430
 431 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 432 {
 433         int res = 0;
 434         unsigned int len;
 435         struct mm_struct *mm = get_task_mm(task);
 436         if (!mm)
 437                 goto out;
 438         if (!mm->arg_end)
 439                 goto out_mm;    /* Shh! No looking before we're done */
 440
 441         len = mm->arg_end - mm->arg_start;
 442
 443         if (len > PAGE_SIZE)
 444                 len = PAGE_SIZE;
 445
 446         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 447
 448         // If the nul at the end of args has been overwritten, then
 449         // assume application is using setproctitle(3).
 450         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 451                 len = strnlen(buffer, res);
 452                 if (len < res) {
 453                     res = len;
 454                 } else {
 455                         len = mm->env_end - mm->env_start;
 456                         if (len > PAGE_SIZE - res)
 457                                 len = PAGE_SIZE - res;
 458                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 459                         res = strnlen(buffer, res);
 460                 }
 461         }
 462 out_mm:
 463         mmput(mm);
 464 out:
 465         return res;
 466 }
 467
 468 static int proc_pid_auxv(struct task_struct *task, char *buffer)
 469 {
 470         int res = 0;
 471         struct mm_struct *mm = get_task_mm(task);
 472         if (mm) {
 473                 unsigned int nwords = 0;
 474                 do
 475                         nwords += 2;
 476                 while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 477                 res = nwords * sizeof(mm->saved_auxv[0]);
 478                 if (res > PAGE_SIZE)
 479                         res = PAGE_SIZE;
 480                 memcpy(buffer, mm->saved_auxv, res);
 481                 mmput(mm);
 482         }
 483         return res;
 484 }
 485
 486
 487 #ifdef CONFIG_KALLSYMS
 488 /*
 489  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 490  * Returns the resolved symbol.  If that fails, simply return the address.
 491  */
 492 static int proc_pid_wchan(struct task_struct *task, char *buffer)
 493 {
 494         char *modname;
 495         const char *sym_name;
 496         unsigned long wchan, size, offset;
 497         char namebuf[KSYM_NAME_LEN+1];
 498
 499         wchan = get_wchan(task);
 500
 501         sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
 502         if (sym_name)
 503                 return sprintf(buffer, "%s", sym_name);
 504         return sprintf(buffer, "%lu", wchan);
 505 }
 506 #endif /* CONFIG_KALLSYMS */
 507
 508 #ifdef CONFIG_SCHEDSTATS
 509 /*
 510  * Provides /proc/PID/schedstat
 511  */
 512 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 513 {
 514         return sprintf(buffer, "%lu %lu %lu\n",
 515                         task->sched_info.cpu_time,
 516                         task->sched_info.run_delay,
 517                         task->sched_info.pcnt);
 518 }
 519 #endif
 520
 521 /* The badness from the OOM killer */
 522 unsigned long badness(struct task_struct *p, unsigned long uptime);
 523 static int proc_oom_score(struct task_struct *task, char *buffer)
 524 {
 525         unsigned long points;
 526         struct timespec uptime;
 527
 528         do_posix_clock_monotonic_gettime(&uptime);
 529         points = badness(task, uptime.tv_sec);
 530         return sprintf(buffer, "%lu\n", points);
 531 }
 532
 533 /************************************************************************/
 534 /*                       Here the fs part begins                        */
 535 /************************************************************************/
 536
 537 /* permission checks */
 538 static int proc_fd_access_allowed(struct inode *inode)
 539 {
 540         struct task_struct *task;
 541         int allowed = 0;
 542         /* Allow access to a task's file descriptors if it is us or we
 543          * may use ptrace attach to the process and find out that
 544          * information.
 545          */
 546         task = get_proc_task(inode);
 547         if (task) {
 548                 allowed = ptrace_may_attach(task);
 549                 put_task_struct(task);
 550         }
 551         return allowed;
 552 }
 553
 554 extern struct seq_operations mounts_op;
 555 struct proc_mounts {
 556         struct seq_file m;
 557         int event;
 558 };
 559
 560 static int mounts_open(struct inode *inode, struct file *file)
 561 {
 562         struct task_struct *task = get_proc_task(inode);
 563         struct namespace *namespace = NULL;
 564         struct proc_mounts *p;
 565         int ret = -EINVAL;
 566
 567         if (task) {
 568                 task_lock(task);
 569                 namespace = task->namespace;
 570                 if (namespace)
 571                         get_namespace(namespace);
 572                 task_unlock(task);
 573                 put_task_struct(task);
 574         }
 575
 576         if (namespace) {
 577                 ret = -ENOMEM;
 578                 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
 579                 if (p) {
 580                         file->private_data = &p->m;
 581                         ret = seq_open(file, &mounts_op);
 582                         if (!ret) {
 583                                 p->m.private = namespace;
 584                                 p->event = namespace->event;
 585                                 return 0;
 586                         }
 587                         kfree(p);
 588                 }
 589                 put_namespace(namespace);
 590         }
 591         return ret;
 592 }
 593
 594 static int mounts_release(struct inode *inode, struct file *file)
 595 {
 596         struct seq_file *m = file->private_data;
 597         struct namespace *namespace = m->private;
 598         put_namespace(namespace);
 599         return seq_release(inode, file);
 600 }
 601
 602 static unsigned mounts_poll(struct file *file, poll_table *wait)
 603 {
 604         struct proc_mounts *p = file->private_data;
 605         struct namespace *ns = p->m.private;
 606         unsigned res = 0;
 607
 608         poll_wait(file, &ns->poll, wait);
 609
 610         spin_lock(&vfsmount_lock);
 611         if (p->event != ns->event) {
 612                 p->event = ns->event;
 613                 res = POLLERR;
 614         }
 615         spin_unlock(&vfsmount_lock);
 616
 617         return res;
 618 }
 619
 620 static struct file_operations proc_mounts_operations = {
 621         .open           = mounts_open,
 622         .read           = seq_read,
 623         .llseek         = seq_lseek,
 624         .release        = mounts_release,
 625         .poll           = mounts_poll,
 626 };
 627
 628 extern struct seq_operations mountstats_op;
 629 static int mountstats_open(struct inode *inode, struct file *file)
 630 {
 631         int ret = seq_open(file, &mountstats_op);
 632
 633         if (!ret) {
 634                 struct seq_file *m = file->private_data;
 635                 struct namespace *namespace = NULL;
 636                 struct task_struct *task = get_proc_task(inode);
 637
 638                 if (task) {
 639                         task_lock(task);
 640                         namespace = task->namespace;
 641                         if (namespace)
 642                                 get_namespace(namespace);
 643                         task_unlock(task);
 644                         put_task_struct(task);
 645                 }
 646
 647                 if (namespace)
 648                         m->private = namespace;
 649                 else {
 650                         seq_release(inode, file);
 651                         ret = -EINVAL;
 652                 }
 653         }
 654         return ret;
 655 }
 656
 657 static struct file_operations proc_mountstats_operations = {
 658         .open           = mountstats_open,
 659         .read           = seq_read,
 660         .llseek         = seq_lseek,
 661         .release        = mounts_release,
 662 };
 663
 664 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 665
 666 static ssize_t proc_info_read(struct file * file, char __user * buf,
 667                           size_t count, loff_t *ppos)
 668 {
 669         struct inode * inode = file->f_dentry->d_inode;
 670         unsigned long page;
 671         ssize_t length;
 672         struct task_struct *task = get_proc_task(inode);
 673
 674         length = -ESRCH;
 675         if (!task)
 676                 goto out_no_task;
 677
 678         if (count > PROC_BLOCK_SIZE)
 679                 count = PROC_BLOCK_SIZE;
 680
 681         length = -ENOMEM;
 682         if (!(page = __get_free_page(GFP_KERNEL)))
 683                 goto out;
 684
 685         length = PROC_I(inode)->op.proc_read(task, (char*)page);
 686
 687         if (length >= 0)
 688                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 689         free_page(page);
 690 out:
 691         put_task_struct(task);
 692 out_no_task:
 693         return length;
 694 }
 695
 696 static struct file_operations proc_info_file_operations = {
 697         .read           = proc_info_read,
 698 };
 699
 700 static int mem_open(struct inode* inode, struct file* file)
 701 {
 702         file->private_data = (void*)((long)current->self_exec_id);
 703         return 0;
 704 }
 705
 706 static ssize_t mem_read(struct file * file, char __user * buf,
 707                         size_t count, loff_t *ppos)
 708 {
 709         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 710         char *page;
 711         unsigned long src = *ppos;
 712         int ret = -ESRCH;
 713         struct mm_struct *mm;
 714
 715         if (!task)
 716                 goto out_no_task;
 717
 718         if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
 719                 goto out;
 720
 721         ret = -ENOMEM;
 722         page = (char *)__get_free_page(GFP_USER);
 723         if (!page)
 724                 goto out;
 725
 726         ret = 0;
 727
 728         mm = get_task_mm(task);
 729         if (!mm)
 730                 goto out_free;
 731
 732         ret = -EIO;
 733
 734         if (file->private_data != (void*)((long)current->self_exec_id))
 735                 goto out_put;
 736
 737         ret = 0;
 738
 739         while (count > 0) {
 740                 int this_len, retval;
 741
 742                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 743                 retval = access_process_vm(task, src, page, this_len, 0);
 744                 if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
 745                         if (!ret)
 746                                 ret = -EIO;
 747                         break;
 748                 }
 749
 750                 if (copy_to_user(buf, page, retval)) {
 751                         ret = -EFAULT;
 752                         break;
 753                 }
 754
 755                 ret += retval;
 756                 src += retval;
 757                 buf += retval;
 758                 count -= retval;
 759         }
 760         *ppos = src;
 761
 762 out_put:
 763         mmput(mm);
 764 out_free:
 765         free_page((unsigned long) page);
 766 out:
 767         put_task_struct(task);
 768 out_no_task:
 769         return ret;
 770 }
 771
 772 #define mem_write NULL
 773
 774 #ifndef mem_write
 775 /* This is a security hazard */
 776 static ssize_t mem_write(struct file * file, const char * buf,
 777                          size_t count, loff_t *ppos)
 778 {
 779         int copied = 0;
 780         char *page;
 781         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 782         unsigned long dst = *ppos;
 783
 784         copied = -ESRCH;
 785         if (!task)
 786                 goto out_no_task;
 787
 788         if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
 789                 goto out;
 790
 791         copied = -ENOMEM;
 792         page = (char *)__get_free_page(GFP_USER);
 793         if (!page)
 794                 goto out;
 795
 796         while (count > 0) {
 797                 int this_len, retval;
 798
 799                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 800                 if (copy_from_user(page, buf, this_len)) {
 801                         copied = -EFAULT;
 802                         break;
 803                 }
 804                 retval = access_process_vm(task, dst, page, this_len, 1);
 805                 if (!retval) {
 806                         if (!copied)
 807                                 copied = -EIO;
 808                         break;
 809                 }
 810                 copied += retval;
 811                 buf += retval;
 812                 dst += retval;
 813                 count -= retval;
 814         }
 815         *ppos = dst;
 816         free_page((unsigned long) page);
 817 out:
 818         put_task_struct(task);
 819 out_no_task:
 820         return copied;
 821 }
 822 #endif
 823
 824 static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
 825 {
 826         switch (orig) {
 827         case 0:
 828                 file->f_pos = offset;
 829                 break;
 830         case 1:
 831                 file->f_pos += offset;
 832                 break;
 833         default:
 834                 return -EINVAL;
 835         }
 836         force_successful_syscall_return();
 837         return file->f_pos;
 838 }
 839
 840 static struct file_operations proc_mem_operations = {
 841         .llseek         = mem_lseek,
 842         .read           = mem_read,
 843         .write          = mem_write,
 844         .open           = mem_open,
 845 };
 846
 847 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
 848                                 size_t count, loff_t *ppos)
 849 {
 850         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 851         char buffer[PROC_NUMBUF];
 852         size_t len;
 853         int oom_adjust;
 854         loff_t __ppos = *ppos;
 855
 856         if (!task)
 857                 return -ESRCH;
 858         oom_adjust = task->oomkilladj;
 859         put_task_struct(task);
 860
 861         len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
 862         if (__ppos >= len)
 863                 return 0;
 864         if (count > len-__ppos)
 865                 count = len-__ppos;
 866         if (copy_to_user(buf, buffer + __ppos, count))
 867                 return -EFAULT;
 868         *ppos = __ppos + count;
 869         return count;
 870 }
 871
 872 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 873                                 size_t count, loff_t *ppos)
 874 {
 875         struct task_struct *task;
 876         char buffer[PROC_NUMBUF], *end;
 877         int oom_adjust;
 878
 879         if (!capable(CAP_SYS_RESOURCE))
 880                 return -EPERM;
 881         memset(buffer, 0, sizeof(buffer));
 882         if (count > sizeof(buffer) - 1)
 883                 count = sizeof(buffer) - 1;
 884         if (copy_from_user(buffer, buf, count))
 885                 return -EFAULT;
 886         oom_adjust = simple_strtol(buffer, &end, 0);
 887         if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
 888                 return -EINVAL;
 889         if (*end == '\n')
 890                 end++;
 891         task = get_proc_task(file->f_dentry->d_inode);
 892         if (!task)
 893                 return -ESRCH;
 894         task->oomkilladj = oom_adjust;
 895         put_task_struct(task);
 896         if (end - buffer == 0)
 897                 return -EIO;
 898         return end - buffer;
 899 }
 900
 901 static struct file_operations proc_oom_adjust_operations = {
 902         .read           = oom_adjust_read,
 903         .write          = oom_adjust_write,
 904 };
 905
 906 #ifdef CONFIG_AUDITSYSCALL
 907 #define TMPBUFLEN 21
 908 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
 909                                   size_t count, loff_t *ppos)
 910 {
 911         struct inode * inode = file->f_dentry->d_inode;
 912         struct task_struct *task = get_proc_task(inode);
 913         ssize_t length;
 914         char tmpbuf[TMPBUFLEN];
 915
 916         if (!task)
 917                 return -ESRCH;
 918         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
 919                                 audit_get_loginuid(task->audit_context));
 920         put_task_struct(task);
 921         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 922 }
 923
 924 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 925                                    size_t count, loff_t *ppos)
 926 {
 927         struct inode * inode = file->f_dentry->d_inode;
 928         char *page, *tmp;
 929         ssize_t length;
 930         uid_t loginuid;
 931
 932         if (!capable(CAP_AUDIT_CONTROL))
 933                 return -EPERM;
 934
 935         if (current != pid_task(proc_pid(inode), PIDTYPE_PID))
 936                 return -EPERM;
 937
 938         if (count >= PAGE_SIZE)
 939                 count = PAGE_SIZE - 1;
 940
 941         if (*ppos != 0) {
 942                 /* No partial writes. */
 943                 return -EINVAL;
 944         }
 945         page = (char*)__get_free_page(GFP_USER);
 946         if (!page)
 947                 return -ENOMEM;
 948         length = -EFAULT;
 949         if (copy_from_user(page, buf, count))
 950                 goto out_free_page;
 951
 952         page[count] = '\0';
 953         loginuid = simple_strtoul(page, &tmp, 10);
 954         if (tmp == page) {
 955                 length = -EINVAL;
 956                 goto out_free_page;
 957
 958         }
 959         length = audit_set_loginuid(current, loginuid);
 960         if (likely(length == 0))
 961                 length = count;
 962
 963 out_free_page:
 964         free_page((unsigned long) page);
 965         return length;
 966 }
 967
 968 static struct file_operations proc_loginuid_operations = {
 969         .read           = proc_loginuid_read,
 970         .write          = proc_loginuid_write,
 971 };
 972 #endif
 973
 974 #ifdef CONFIG_SECCOMP
 975 static ssize_t seccomp_read(struct file *file, char __user *buf,
 976                             size_t count, loff_t *ppos)
 977 {
 978         struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode);
 979         char __buf[20];
 980         loff_t __ppos = *ppos;
 981         size_t len;
 982
 983         if (!tsk)
 984                 return -ESRCH;
 985         /* no need to print the trailing zero, so use only len */
 986         len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
 987         put_task_struct(tsk);
 988         if (__ppos >= len)
 989                 return 0;
 990         if (count > len - __ppos)
 991                 count = len - __ppos;
 992         if (copy_to_user(buf, __buf + __ppos, count))
 993                 return -EFAULT;
 994         *ppos = __ppos + count;
 995         return count;
 996 }
 997
 998 static ssize_t seccomp_write(struct file *file, const char __user *buf,
 999                              size_t count, loff_t *ppos)
1000 {
1001         struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode);
1002         char __buf[20], *end;
1003         unsigned int seccomp_mode;
1004         ssize_t result;
1005
1006         result = -ESRCH;
1007         if (!tsk)
1008                 goto out_no_task;
1009
1010         /* can set it only once to be even more secure */
1011         result = -EPERM;
1012         if (unlikely(tsk->seccomp.mode))
1013                 goto out;
1014
1015         result = -EFAULT;
1016         memset(__buf, 0, sizeof(__buf));
1017         count = min(count, sizeof(__buf) - 1);
1018         if (copy_from_user(__buf, buf, count))
1019                 goto out;
1020
1021         seccomp_mode = simple_strtoul(__buf, &end, 0);
1022         if (*end == '\n')
1023                 end++;
1024         result = -EINVAL;
1025         if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
1026                 tsk->seccomp.mode = seccomp_mode;
1027                 set_tsk_thread_flag(tsk, TIF_SECCOMP);
1028         } else
1029                 goto out;
1030         result = -EIO;
1031         if (unlikely(!(end - __buf)))
1032                 goto out;
1033         result = end - __buf;
1034 out:
1035         put_task_struct(tsk);
1036 out_no_task:
1037         return result;
1038 }
1039
1040 static struct file_operations proc_seccomp_operations = {
1041         .read           = seccomp_read,
1042         .write          = seccomp_write,
1043 };
1044 #endif /* CONFIG_SECCOMP */
1045
1046 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1047 {
1048         struct inode *inode = dentry->d_inode;
1049         int error = -EACCES;
1050
1051         /* We don't need a base pointer in the /proc filesystem */
1052         path_release(nd);
1053
1054         /* Are we allowed to snoop on the tasks file descriptors? */
1055         if (!proc_fd_access_allowed(inode))
1056                 goto out;
1057
1058         error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
1059         nd->last_type = LAST_BIND;
1060 out:
1061         return ERR_PTR(error);
1062 }
1063
1064 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
1065                             char __user *buffer, int buflen)
1066 {
1067         struct inode * inode;
1068         char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
1069         int len;
1070
1071         if (!tmp)
1072                 return -ENOMEM;
1073
1074         inode = dentry->d_inode;
1075         path = d_path(dentry, mnt, tmp, PAGE_SIZE);
1076         len = PTR_ERR(path);
1077         if (IS_ERR(path))
1078                 goto out;
1079         len = tmp + PAGE_SIZE - 1 - path;
1080
1081         if (len > buflen)
1082                 len = buflen;
1083         if (copy_to_user(buffer, path, len))
1084                 len = -EFAULT;
1085  out:
1086         free_page((unsigned long)tmp);
1087         return len;
1088 }
1089
1090 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1091 {
1092         int error = -EACCES;
1093         struct inode *inode = dentry->d_inode;
1094         struct dentry *de;
1095         struct vfsmount *mnt = NULL;
1096
1097         /* Are we allowed to snoop on the tasks file descriptors? */
1098         if (!proc_fd_access_allowed(inode))
1099                 goto out;
1100
1101         error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
1102         if (error)
1103                 goto out;
1104
1105         error = do_proc_readlink(de, mnt, buffer, buflen);
1106         dput(de);
1107         mntput(mnt);
1108 out:
1109         return error;
1110 }
1111
1112 static struct inode_operations proc_pid_link_inode_operations = {
1113         .readlink       = proc_pid_readlink,
1114         .follow_link    = proc_pid_follow_link
1115 };
1116
1117 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
1118 {
1119         struct dentry *dentry = filp->f_dentry;
1120         struct inode *inode = dentry->d_inode;
1121         struct task_struct *p = get_proc_task(inode);
1122         unsigned int fd, tid, ino;
1123         int retval;
1124         char buf[PROC_NUMBUF];
1125         struct files_struct * files;
1126         struct fdtable *fdt;
1127
1128         retval = -ENOENT;
1129         if (!p)
1130                 goto out_no_task;
1131         retval = 0;
1132         tid = p->pid;
1133
1134         fd = filp->f_pos;
1135         switch (fd) {
1136                 case 0:
1137                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1138                                 goto out;
1139                         filp->f_pos++;
1140                 case 1:
1141                         ino = parent_ino(dentry);
1142                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1143                                 goto out;
1144                         filp->f_pos++;
1145                 default:
1146                         files = get_files_struct(p);
1147                         if (!files)
1148                                 goto out;
1149                         rcu_read_lock();
1150                         fdt = files_fdtable(files);
1151                         for (fd = filp->f_pos-2;
1152                              fd < fdt->max_fds;
1153                              fd++, filp->f_pos++) {
1154                                 unsigned int i,j;
1155
1156                                 if (!fcheck_files(files, fd))
1157                                         continue;
1158                                 rcu_read_unlock();
1159
1160                                 j = PROC_NUMBUF;
1161                                 i = fd;
1162                                 do {
1163                                         j--;
1164                                         buf[j] = '0' + (i % 10);
1165                                         i /= 10;
1166                                 } while (i);
1167
1168                                 ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
1169                                 if (filldir(dirent, buf+j, PROC_NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
1170                                         rcu_read_lock();
1171                                         break;
1172                                 }
1173                                 rcu_read_lock();
1174                         }
1175                         rcu_read_unlock();
1176                         put_files_struct(files);
1177         }
1178 out:
1179         put_task_struct(p);
1180 out_no_task:
1181         return retval;
1182 }
1183
1184 static int proc_pident_readdir(struct file *filp,
1185                 void *dirent, filldir_t filldir,
1186                 struct pid_entry *ents, unsigned int nents)
1187 {
1188         int i;
1189         int pid;
1190         struct dentry *dentry = filp->f_dentry;
1191         struct inode *inode = dentry->d_inode;
1192         struct task_struct *task = get_proc_task(inode);
1193         struct pid_entry *p;
1194         ino_t ino;
1195         int ret;
1196
1197         ret = -ENOENT;
1198         if (!task)
1199                 goto out;
1200
1201         ret = 0;
1202         pid = task->pid;
1203         put_task_struct(task);
1204         i = filp->f_pos;
1205         switch (i) {
1206         case 0:
1207                 ino = inode->i_ino;
1208                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1209                         goto out;
1210                 i++;
1211                 filp->f_pos++;
1212                 /* fall through */
1213         case 1:
1214                 ino = parent_ino(dentry);
1215                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1216                         goto out;
1217                 i++;
1218                 filp->f_pos++;
1219                 /* fall through */
1220         default:
1221                 i -= 2;
1222                 if (i >= nents) {
1223                         ret = 1;
1224                         goto out;
1225                 }
1226                 p = ents + i;
1227                 while (p->name) {
1228                         if (filldir(dirent, p->name, p->len, filp->f_pos,
1229                                     fake_ino(pid, p->type), p->mode >> 12) < 0)
1230                                 goto out;
1231                         filp->f_pos++;
1232                         p++;
1233                 }
1234         }
1235
1236         ret = 1;
1237 out:
1238         return ret;
1239 }
1240
1241 static int proc_tgid_base_readdir(struct file * filp,
1242                              void * dirent, filldir_t filldir)
1243 {
1244         return proc_pident_readdir(filp,dirent,filldir,
1245                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
1246 }
1247
1248 static int proc_tid_base_readdir(struct file * filp,
1249                              void * dirent, filldir_t filldir)
1250 {
1251         return proc_pident_readdir(filp,dirent,filldir,
1252                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
1253 }
1254
1255 /* building an inode */
1256
1257 static int task_dumpable(struct task_struct *task)
1258 {
1259         int dumpable = 0;
1260         struct mm_struct *mm;
1261
1262         task_lock(task);
1263         mm = task->mm;
1264         if (mm)
1265                 dumpable = mm->dumpable;
1266         task_unlock(task);
1267         if(dumpable == 1)
1268                 return 1;
1269         return 0;
1270 }
1271
1272
1273 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
1274 {
1275         struct inode * inode;
1276         struct proc_inode *ei;
1277
1278         /* We need a new inode */
1279
1280         inode = new_inode(sb);
1281         if (!inode)
1282                 goto out;
1283
1284         /* Common stuff */
1285         ei = PROC_I(inode);
1286         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1287         inode->i_ino = fake_ino(task->pid, ino);
1288
1289         /*
1290          * grab the reference to task.
1291          */
1292         ei->pid = get_pid(task->pids[PIDTYPE_PID].pid);
1293         if (!ei->pid)
1294                 goto out_unlock;
1295
1296         inode->i_uid = 0;
1297         inode->i_gid = 0;
1298         if (task_dumpable(task)) {
1299                 inode->i_uid = task->euid;
1300                 inode->i_gid = task->egid;
1301         }
1302         security_task_to_inode(task, inode);
1303
1304 out:
1305         return inode;
1306
1307 out_unlock:
1308         iput(inode);
1309         return NULL;
1310 }
1311
1312 /* dentry stuff */
1313
1314 /*
1315  *      Exceptional case: normally we are not allowed to unhash a busy
1316  * directory. In this case, however, we can do it - no aliasing problems
1317  * due to the way we treat inodes.
1318  *
1319  * Rewrite the inode's ownerships here because the owning task may have
1320  * performed a setuid(), etc.
1321  *
1322  * Before the /proc/pid/status file was created the only way to read
1323  * the effective uid of a /process was to stat /proc/pid.  Reading
1324  * /proc/pid/status is slow enough that procps and other packages
1325  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1326  * made this apply to all per process world readable and executable
1327  * directories.
1328  */
1329 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1330 {
1331         struct inode *inode = dentry->d_inode;
1332         struct task_struct *task = get_proc_task(inode);
1333         if (task) {
1334                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1335                     task_dumpable(task)) {
1336                         inode->i_uid = task->euid;
1337                         inode->i_gid = task->egid;
1338                 } else {
1339                         inode->i_uid = 0;
1340                         inode->i_gid = 0;
1341                 }
1342                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1343                 security_task_to_inode(task, inode);
1344                 put_task_struct(task);
1345                 return 1;
1346         }
1347         d_drop(dentry);
1348         return 0;
1349 }
1350
1351 static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1352 {
1353         struct inode *inode = dentry->d_inode;
1354         struct task_struct *task;
1355         generic_fillattr(inode, stat);
1356
1357         rcu_read_lock();
1358         stat->uid = 0;
1359         stat->gid = 0;
1360         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1361         if (task) {
1362                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1363                     task_dumpable(task)) {
1364                         stat->uid = task->euid;
1365                         stat->gid = task->egid;
1366                 }
1367         }
1368         rcu_read_unlock();
1369         return 0;
1370 }
1371
1372 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1373 {
1374         struct inode *inode = dentry->d_inode;
1375         struct task_struct *task = get_proc_task(inode);
1376         int fd = proc_fd(inode);
1377         struct files_struct *files;
1378
1379         if (task) {
1380                 files = get_files_struct(task);
1381                 if (files) {
1382                         rcu_read_lock();
1383                         if (fcheck_files(files, fd)) {
1384                                 rcu_read_unlock();
1385                                 put_files_struct(files);
1386                                 if (task_dumpable(task)) {
1387                                         inode->i_uid = task->euid;
1388                                         inode->i_gid = task->egid;
1389                                 } else {
1390                                         inode->i_uid = 0;
1391                                         inode->i_gid = 0;
1392                                 }
1393                                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1394                                 security_task_to_inode(task, inode);
1395                                 put_task_struct(task);
1396                                 return 1;
1397                         }
1398                         rcu_read_unlock();
1399                         put_files_struct(files);
1400                 }
1401                 put_task_struct(task);
1402         }
1403         d_drop(dentry);
1404         return 0;
1405 }
1406
1407 static int pid_delete_dentry(struct dentry * dentry)
1408 {
1409         /* Is the task we represent dead?
1410          * If so, then don't put the dentry on the lru list,
1411          * kill it immediately.
1412          */
1413         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1414 }
1415
1416 static struct dentry_operations tid_fd_dentry_operations =
1417 {
1418         .d_revalidate   = tid_fd_revalidate,
1419         .d_delete       = pid_delete_dentry,
1420 };
1421
1422 static struct dentry_operations pid_dentry_operations =
1423 {
1424         .d_revalidate   = pid_revalidate,
1425         .d_delete       = pid_delete_dentry,
1426 };
1427
1428 /* Lookups */
1429
1430 static unsigned name_to_int(struct dentry *dentry)
1431 {
1432         const char *name = dentry->d_name.name;
1433         int len = dentry->d_name.len;
1434         unsigned n = 0;
1435
1436         if (len > 1 && *name == '0')
1437                 goto out;
1438         while (len-- > 0) {
1439                 unsigned c = *name++ - '0';
1440                 if (c > 9)
1441                         goto out;
1442                 if (n >= (~0U-9)/10)
1443                         goto out;
1444                 n *= 10;
1445                 n += c;
1446         }
1447         return n;
1448 out:
1449         return ~0U;
1450 }
1451
1452 /* SMP-safe */
1453 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
1454 {
1455         struct task_struct *task = get_proc_task(dir);
1456         unsigned fd = name_to_int(dentry);
1457         struct dentry *result = ERR_PTR(-ENOENT);
1458         struct file * file;
1459         struct files_struct * files;
1460         struct inode *inode;
1461         struct proc_inode *ei;
1462
1463         if (!task)
1464                 goto out_no_task;
1465         if (fd == ~0U)
1466                 goto out;
1467
1468         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
1469         if (!inode)
1470                 goto out;
1471         ei = PROC_I(inode);
1472         ei->fd = fd;
1473         files = get_files_struct(task);
1474         if (!files)
1475                 goto out_unlock;
1476         inode->i_mode = S_IFLNK;
1477
1478         /*
1479          * We are not taking a ref to the file structure, so we must
1480          * hold ->file_lock.
1481          */
1482         spin_lock(&files->file_lock);
1483         file = fcheck_files(files, fd);
1484         if (!file)
1485                 goto out_unlock2;
1486         if (file->f_mode & 1)
1487                 inode->i_mode |= S_IRUSR | S_IXUSR;
1488         if (file->f_mode & 2)
1489                 inode->i_mode |= S_IWUSR | S_IXUSR;
1490         spin_unlock(&files->file_lock);
1491         put_files_struct(files);
1492         inode->i_op = &proc_pid_link_inode_operations;
1493         inode->i_size = 64;
1494         ei->op.proc_get_link = proc_fd_link;
1495         dentry->d_op = &tid_fd_dentry_operations;
1496         d_add(dentry, inode);
1497         /* Close the race of the process dying before we return the dentry */
1498         if (tid_fd_revalidate(dentry, NULL))
1499                 result = NULL;
1500 out:
1501         put_task_struct(task);
1502 out_no_task:
1503         return result;
1504
1505 out_unlock2:
1506         spin_unlock(&files->file_lock);
1507         put_files_struct(files);
1508 out_unlock:
1509         iput(inode);
1510         goto out;
1511 }
1512
1513 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
1514 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
1515 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat);
1516
1517 static struct file_operations proc_fd_operations = {
1518         .read           = generic_read_dir,
1519         .readdir        = proc_readfd,
1520 };
1521
1522 static struct file_operations proc_task_operations = {
1523         .read           = generic_read_dir,
1524         .readdir        = proc_task_readdir,
1525 };
1526
1527 /*
1528  * proc directories can do almost nothing..
1529  */
1530 static struct inode_operations proc_fd_inode_operations = {
1531         .lookup         = proc_lookupfd,
1532 };
1533
1534 static struct inode_operations proc_task_inode_operations = {
1535         .lookup         = proc_task_lookup,
1536         .getattr        = proc_task_getattr,
1537 };
1538
1539 #ifdef CONFIG_SECURITY
1540 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
1541                                   size_t count, loff_t *ppos)
1542 {
1543         struct inode * inode = file->f_dentry->d_inode;
1544         unsigned long page;
1545         ssize_t length;
1546         struct task_struct *task = get_proc_task(inode);
1547
1548         length = -ESRCH;
1549         if (!task)
1550                 goto out_no_task;
1551
1552         if (count > PAGE_SIZE)
1553                 count = PAGE_SIZE;
1554         length = -ENOMEM;
1555         if (!(page = __get_free_page(GFP_KERNEL)))
1556                 goto out;
1557
1558         length = security_getprocattr(task,
1559                                       (char*)file->f_dentry->d_name.name,
1560                                       (void*)page, count);
1561         if (length >= 0)
1562                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
1563         free_page(page);
1564 out:
1565         put_task_struct(task);
1566 out_no_task:
1567         return length;
1568 }
1569
1570 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
1571                                    size_t count, loff_t *ppos)
1572 {
1573         struct inode * inode = file->f_dentry->d_inode;
1574         char *page;
1575         ssize_t length;
1576         struct task_struct *task = get_proc_task(inode);
1577
1578         length = -ESRCH;
1579         if (!task)
1580                 goto out_no_task;
1581         if (count > PAGE_SIZE)
1582                 count = PAGE_SIZE;
1583
1584         /* No partial writes. */
1585         length = -EINVAL;
1586         if (*ppos != 0)
1587                 goto out;
1588
1589         length = -ENOMEM;
1590         page = (char*)__get_free_page(GFP_USER);
1591         if (!page)
1592                 goto out;
1593
1594         length = -EFAULT;
1595         if (copy_from_user(page, buf, count))
1596                 goto out_free;
1597
1598         length = security_setprocattr(task,
1599                                       (char*)file->f_dentry->d_name.name,
1600                                       (void*)page, count);
1601 out_free:
1602         free_page((unsigned long) page);
1603 out:
1604         put_task_struct(task);
1605 out_no_task:
1606         return length;
1607 }
1608
1609 static struct file_operations proc_pid_attr_operations = {
1610         .read           = proc_pid_attr_read,
1611         .write          = proc_pid_attr_write,
1612 };
1613
1614 static struct file_operations proc_tid_attr_operations;
1615 static struct inode_operations proc_tid_attr_inode_operations;
1616 static struct file_operations proc_tgid_attr_operations;
1617 static struct inode_operations proc_tgid_attr_inode_operations;
1618 #endif
1619
1620 /* SMP-safe */
1621 static struct dentry *proc_pident_lookup(struct inode *dir,
1622                                          struct dentry *dentry,
1623                                          struct pid_entry *ents)
1624 {
1625         struct inode *inode;
1626         struct dentry *error;
1627         struct task_struct *task = get_proc_task(dir);
1628         struct pid_entry *p;
1629         struct proc_inode *ei;
1630
1631         error = ERR_PTR(-ENOENT);
1632         inode = NULL;
1633
1634         if (!task)
1635                 goto out_no_task;
1636
1637         for (p = ents; p->name; p++) {
1638                 if (p->len != dentry->d_name.len)
1639                         continue;
1640                 if (!memcmp(dentry->d_name.name, p->name, p->len))
1641                         break;
1642         }
1643         if (!p->name)
1644                 goto out;
1645
1646         error = ERR_PTR(-EINVAL);
1647         inode = proc_pid_make_inode(dir->i_sb, task, p->type);
1648         if (!inode)
1649                 goto out;
1650
1651         ei = PROC_I(inode);
1652         inode->i_mode = p->mode;
1653         /*
1654          * Yes, it does not scale. And it should not. Don't add
1655          * new entries into /proc/<tgid>/ without very good reasons.
1656          */
1657         switch(p->type) {
1658                 case PROC_TGID_TASK:
1659                         inode->i_nlink = 2;
1660                         inode->i_op = &proc_task_inode_operations;
1661                         inode->i_fop = &proc_task_operations;
1662                         break;
1663                 case PROC_TID_FD:
1664                 case PROC_TGID_FD:
1665                         inode->i_nlink = 2;
1666                         inode->i_op = &proc_fd_inode_operations;
1667                         inode->i_fop = &proc_fd_operations;
1668                         break;
1669                 case PROC_TID_EXE:
1670                 case PROC_TGID_EXE:
1671                         inode->i_op = &proc_pid_link_inode_operations;
1672                         ei->op.proc_get_link = proc_exe_link;
1673                         break;
1674                 case PROC_TID_CWD:
1675                 case PROC_TGID_CWD:
1676                         inode->i_op = &proc_pid_link_inode_operations;
1677                         ei->op.proc_get_link = proc_cwd_link;
1678                         break;
1679                 case PROC_TID_ROOT:
1680                 case PROC_TGID_ROOT:
1681                         inode->i_op = &proc_pid_link_inode_operations;
1682                         ei->op.proc_get_link = proc_root_link;
1683                         break;
1684                 case PROC_TID_ENVIRON:
1685                 case PROC_TGID_ENVIRON:
1686                         inode->i_fop = &proc_info_file_operations;
1687                         ei->op.proc_read = proc_pid_environ;
1688                         break;
1689                 case PROC_TID_AUXV:
1690                 case PROC_TGID_AUXV:
1691                         inode->i_fop = &proc_info_file_operations;
1692                         ei->op.proc_read = proc_pid_auxv;
1693                         break;
1694                 case PROC_TID_STATUS:
1695                 case PROC_TGID_STATUS:
1696                         inode->i_fop = &proc_info_file_operations;
1697                         ei->op.proc_read = proc_pid_status;
1698                         break;
1699                 case PROC_TID_STAT:
1700                         inode->i_fop = &proc_info_file_operations;
1701                         ei->op.proc_read = proc_tid_stat;
1702                         break;
1703                 case PROC_TGID_STAT:
1704                         inode->i_fop = &proc_info_file_operations;
1705                         ei->op.proc_read = proc_tgid_stat;
1706                         break;
1707                 case PROC_TID_CMDLINE:
1708                 case PROC_TGID_CMDLINE:
1709                         inode->i_fop = &proc_info_file_operations;
1710                         ei->op.proc_read = proc_pid_cmdline;
1711                         break;
1712                 case PROC_TID_STATM:
1713                 case PROC_TGID_STATM:
1714                         inode->i_fop = &proc_info_file_operations;
1715                         ei->op.proc_read = proc_pid_statm;
1716                         break;
1717                 case PROC_TID_MAPS:
1718                 case PROC_TGID_MAPS:
1719                         inode->i_fop = &proc_maps_operations;
1720                         break;
1721 #ifdef CONFIG_NUMA
1722                 case PROC_TID_NUMA_MAPS:
1723                 case PROC_TGID_NUMA_MAPS:
1724                         inode->i_fop = &proc_numa_maps_operations;
1725                         break;
1726 #endif
1727                 case PROC_TID_MEM:
1728                 case PROC_TGID_MEM:
1729                         inode->i_fop = &proc_mem_operations;
1730                         break;
1731 #ifdef CONFIG_SECCOMP
1732                 case PROC_TID_SECCOMP:
1733                 case PROC_TGID_SECCOMP:
1734                         inode->i_fop = &proc_seccomp_operations;
1735                         break;
1736 #endif /* CONFIG_SECCOMP */
1737                 case PROC_TID_MOUNTS:
1738                 case PROC_TGID_MOUNTS:
1739                         inode->i_fop = &proc_mounts_operations;
1740                         break;
1741 #ifdef CONFIG_MMU
1742                 case PROC_TID_SMAPS:
1743                 case PROC_TGID_SMAPS:
1744                         inode->i_fop = &proc_smaps_operations;
1745                         break;
1746 #endif
1747                 case PROC_TID_MOUNTSTATS:
1748                 case PROC_TGID_MOUNTSTATS:
1749                         inode->i_fop = &proc_mountstats_operations;
1750                         break;
1751 #ifdef CONFIG_SECURITY
1752                 case PROC_TID_ATTR:
1753                         inode->i_nlink = 2;
1754                         inode->i_op = &proc_tid_attr_inode_operations;
1755                         inode->i_fop = &proc_tid_attr_operations;
1756                         break;
1757                 case PROC_TGID_ATTR:
1758                         inode->i_nlink = 2;
1759                         inode->i_op = &proc_tgid_attr_inode_operations;
1760                         inode->i_fop = &proc_tgid_attr_operations;
1761                         break;
1762                 case PROC_TID_ATTR_CURRENT:
1763                 case PROC_TGID_ATTR_CURRENT:
1764                 case PROC_TID_ATTR_PREV:
1765                 case PROC_TGID_ATTR_PREV:
1766                 case PROC_TID_ATTR_EXEC:
1767                 case PROC_TGID_ATTR_EXEC:
1768                 case PROC_TID_ATTR_FSCREATE:
1769                 case PROC_TGID_ATTR_FSCREATE:
1770                 case PROC_TID_ATTR_KEYCREATE:
1771                 case PROC_TGID_ATTR_KEYCREATE:
1772                 case PROC_TID_ATTR_SOCKCREATE:
1773                 case PROC_TGID_ATTR_SOCKCREATE:
1774                         inode->i_fop = &proc_pid_attr_operations;
1775                         break;
1776 #endif
1777 #ifdef CONFIG_KALLSYMS
1778                 case PROC_TID_WCHAN:
1779                 case PROC_TGID_WCHAN:
1780                         inode->i_fop = &proc_info_file_operations;
1781                         ei->op.proc_read = proc_pid_wchan;
1782                         break;
1783 #endif
1784 #ifdef CONFIG_SCHEDSTATS
1785                 case PROC_TID_SCHEDSTAT:
1786                 case PROC_TGID_SCHEDSTAT:
1787                         inode->i_fop = &proc_info_file_operations;
1788                         ei->op.proc_read = proc_pid_schedstat;
1789                         break;
1790 #endif
1791 #ifdef CONFIG_CPUSETS
1792                 case PROC_TID_CPUSET:
1793                 case PROC_TGID_CPUSET:
1794                         inode->i_fop = &proc_cpuset_operations;
1795                         break;
1796 #endif
1797                 case PROC_TID_OOM_SCORE:
1798                 case PROC_TGID_OOM_SCORE:
1799                         inode->i_fop = &proc_info_file_operations;
1800                         ei->op.proc_read = proc_oom_score;
1801                         break;
1802                 case PROC_TID_OOM_ADJUST:
1803                 case PROC_TGID_OOM_ADJUST:
1804                         inode->i_fop = &proc_oom_adjust_operations;
1805                         break;
1806 #ifdef CONFIG_AUDITSYSCALL
1807                 case PROC_TID_LOGINUID:
1808                 case PROC_TGID_LOGINUID:
1809                         inode->i_fop = &proc_loginuid_operations;
1810                         break;
1811 #endif
1812                 default:
1813                         printk("procfs: impossible type (%d)",p->type);
1814                         iput(inode);
1815                         error = ERR_PTR(-EINVAL);
1816                         goto out;
1817         }
1818         dentry->d_op = &pid_dentry_operations;
1819         d_add(dentry, inode);
1820         /* Close the race of the process dying before we return the dentry */
1821         if (pid_revalidate(dentry, NULL))
1822                 error = NULL;
1823 out:
1824         put_task_struct(task);
1825 out_no_task:
1826         return error;
1827 }
1828
1829 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1830         return proc_pident_lookup(dir, dentry, tgid_base_stuff);
1831 }
1832
1833 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1834         return proc_pident_lookup(dir, dentry, tid_base_stuff);
1835 }
1836
1837 static struct file_operations proc_tgid_base_operations = {
1838         .read           = generic_read_dir,
1839         .readdir        = proc_tgid_base_readdir,
1840 };
1841
1842 static struct file_operations proc_tid_base_operations = {
1843         .read           = generic_read_dir,
1844         .readdir        = proc_tid_base_readdir,
1845 };
1846
1847 static struct inode_operations proc_tgid_base_inode_operations = {
1848         .lookup         = proc_tgid_base_lookup,
1849         .getattr        = pid_getattr,
1850 };
1851
1852 static struct inode_operations proc_tid_base_inode_operations = {
1853         .lookup         = proc_tid_base_lookup,
1854         .getattr        = pid_getattr,
1855 };
1856
1857 #ifdef CONFIG_SECURITY
1858 static int proc_tgid_attr_readdir(struct file * filp,
1859                              void * dirent, filldir_t filldir)
1860 {
1861         return proc_pident_readdir(filp,dirent,filldir,
1862                                    tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
1863 }
1864
1865 static int proc_tid_attr_readdir(struct file * filp,
1866                              void * dirent, filldir_t filldir)
1867 {
1868         return proc_pident_readdir(filp,dirent,filldir,
1869                                    tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
1870 }
1871
1872 static struct file_operations proc_tgid_attr_operations = {
1873         .read           = generic_read_dir,
1874         .readdir        = proc_tgid_attr_readdir,
1875 };
1876
1877 static struct file_operations proc_tid_attr_operations = {
1878         .read           = generic_read_dir,
1879         .readdir        = proc_tid_attr_readdir,
1880 };
1881
1882 static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
1883                                 struct dentry *dentry, struct nameidata *nd)
1884 {
1885         return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
1886 }
1887
1888 static struct dentry *proc_tid_attr_lookup(struct inode *dir,
1889                                 struct dentry *dentry, struct nameidata *nd)
1890 {
1891         return proc_pident_lookup(dir, dentry, tid_attr_stuff);
1892 }
1893
1894 static struct inode_operations proc_tgid_attr_inode_operations = {
1895         .lookup         = proc_tgid_attr_lookup,
1896         .getattr        = pid_getattr,
1897 };
1898
1899 static struct inode_operations proc_tid_attr_inode_operations = {
1900         .lookup         = proc_tid_attr_lookup,
1901         .getattr        = pid_getattr,
1902 };
1903 #endif
1904
1905 /*
1906  * /proc/self:
1907  */
1908 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
1909                               int buflen)
1910 {
1911         char tmp[PROC_NUMBUF];
1912         sprintf(tmp, "%d", current->tgid);
1913         return vfs_readlink(dentry,buffer,buflen,tmp);
1914 }
1915
1916 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
1917 {
1918         char tmp[PROC_NUMBUF];
1919         sprintf(tmp, "%d", current->tgid);
1920         return ERR_PTR(vfs_follow_link(nd,tmp));
1921 }
1922
1923 static struct inode_operations proc_self_inode_operations = {
1924         .readlink       = proc_self_readlink,
1925         .follow_link    = proc_self_follow_link,
1926 };
1927
1928 /**
1929  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
1930  *
1931  * @task: task that should be flushed.
1932  *
1933  * Looks in the dcache for
1934  * /proc/@pid
1935  * /proc/@tgid/task/@pid
1936  * if either directory is present flushes it and all of it'ts children
1937  * from the dcache.
1938  *
1939  * It is safe and reasonable to cache /proc entries for a task until
1940  * that task exits.  After that they just clog up the dcache with
1941  * useless entries, possibly causing useful dcache entries to be
1942  * flushed instead.  This routine is proved to flush those useless
1943  * dcache entries at process exit time.
1944  *
1945  * NOTE: This routine is just an optimization so it does not guarantee
1946  *       that no dcache entries will exist at process exit time it
1947  *       just makes it very unlikely that any will persist.
1948  */
1949 void proc_flush_task(struct task_struct *task)
1950 {
1951         struct dentry *dentry, *leader, *dir;
1952         char buf[PROC_NUMBUF];
1953         struct qstr name;
1954
1955         name.name = buf;
1956         name.len = snprintf(buf, sizeof(buf), "%d", task->pid);
1957         dentry = d_hash_and_lookup(proc_mnt->mnt_root, &name);
1958         if (dentry) {
1959                 shrink_dcache_parent(dentry);
1960                 d_drop(dentry);
1961                 dput(dentry);
1962         }
1963
1964         if (thread_group_leader(task))
1965                 goto out;
1966
1967         name.name = buf;
1968         name.len = snprintf(buf, sizeof(buf), "%d", task->tgid);
1969         leader = d_hash_and_lookup(proc_mnt->mnt_root, &name);
1970         if (!leader)
1971                 goto out;
1972
1973         name.name = "task";
1974         name.len = strlen(name.name);
1975         dir = d_hash_and_lookup(leader, &name);
1976         if (!dir)
1977                 goto out_put_leader;
1978
1979         name.name = buf;
1980         name.len = snprintf(buf, sizeof(buf), "%d", task->pid);
1981         dentry = d_hash_and_lookup(dir, &name);
1982         if (dentry) {
1983                 shrink_dcache_parent(dentry);
1984                 d_drop(dentry);
1985                 dput(dentry);
1986         }
1987
1988         dput(dir);
1989 out_put_leader:
1990         dput(leader);
1991 out:
1992         return;
1993 }
1994
1995 /* SMP-safe */
1996 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1997 {
1998         struct dentry *result = ERR_PTR(-ENOENT);
1999         struct task_struct *task;
2000         struct inode *inode;
2001         struct proc_inode *ei;
2002         unsigned tgid;
2003
2004         if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
2005                 inode = new_inode(dir->i_sb);
2006                 if (!inode)
2007                         return ERR_PTR(-ENOMEM);
2008                 ei = PROC_I(inode);
2009                 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2010                 inode->i_ino = fake_ino(0, PROC_TGID_INO);
2011                 ei->pde = NULL;
2012                 inode->i_mode = S_IFLNK|S_IRWXUGO;
2013                 inode->i_uid = inode->i_gid = 0;
2014                 inode->i_size = 64;
2015                 inode->i_op = &proc_self_inode_operations;
2016                 d_add(dentry, inode);
2017                 return NULL;
2018         }
2019         tgid = name_to_int(dentry);
2020         if (tgid == ~0U)
2021                 goto out;
2022
2023         rcu_read_lock();
2024         task = find_task_by_pid(tgid);
2025         if (task)
2026                 get_task_struct(task);
2027         rcu_read_unlock();
2028         if (!task)
2029                 goto out;
2030
2031         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
2032         if (!inode)
2033                 goto out_put_task;
2034
2035         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2036         inode->i_op = &proc_tgid_base_inode_operations;
2037         inode->i_fop = &proc_tgid_base_operations;
2038         inode->i_flags|=S_IMMUTABLE;
2039 #ifdef CONFIG_SECURITY
2040         inode->i_nlink = 5;
2041 #else
2042         inode->i_nlink = 4;
2043 #endif
2044
2045         dentry->d_op = &pid_dentry_operations;
2046
2047         d_add(dentry, inode);
2048         /* Close the race of the process dying before we return the dentry */
2049         if (pid_revalidate(dentry, NULL))
2050                 result = NULL;
2051
2052 out_put_task:
2053         put_task_struct(task);
2054 out:
2055         return result;
2056 }
2057
2058 /* SMP-safe */
2059 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2060 {
2061         struct dentry *result = ERR_PTR(-ENOENT);
2062         struct task_struct *task;
2063         struct task_struct *leader = get_proc_task(dir);
2064         struct inode *inode;
2065         unsigned tid;
2066
2067         if (!leader)
2068                 goto out_no_task;
2069
2070         tid = name_to_int(dentry);
2071         if (tid == ~0U)
2072                 goto out;
2073
2074         rcu_read_lock();
2075         task = find_task_by_pid(tid);
2076         if (task)
2077                 get_task_struct(task);
2078         rcu_read_unlock();
2079         if (!task)
2080                 goto out;
2081         if (leader->tgid != task->tgid)
2082                 goto out_drop_task;
2083
2084         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);
2085
2086
2087         if (!inode)
2088                 goto out_drop_task;
2089         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2090         inode->i_op = &proc_tid_base_inode_operations;
2091         inode->i_fop = &proc_tid_base_operations;
2092         inode->i_flags|=S_IMMUTABLE;
2093 #ifdef CONFIG_SECURITY
2094         inode->i_nlink = 4;
2095 #else
2096         inode->i_nlink = 3;
2097 #endif
2098
2099         dentry->d_op = &pid_dentry_operations;
2100
2101         d_add(dentry, inode);
2102         /* Close the race of the process dying before we return the dentry */
2103         if (pid_revalidate(dentry, NULL))
2104                 result = NULL;
2105
2106 out_drop_task:
2107         put_task_struct(task);
2108 out:
2109         put_task_struct(leader);
2110 out_no_task:
2111         return result;
2112 }
2113
2114 /*
2115  * Find the first tgid to return to user space.
2116  *
2117  * Usually this is just whatever follows &init_task, but if the users
2118  * buffer was too small to hold the full list or there was a seek into
2119  * the middle of the directory we have more work to do.
2120  *
2121  * In the case of a short read we start with find_task_by_pid.
2122  *
2123  * In the case of a seek we start with &init_task and walk nr
2124  * threads past it.
2125  */
2126 static struct task_struct *first_tgid(int tgid, unsigned int nr)
2127 {
2128         struct task_struct *pos;
2129         rcu_read_lock();
2130         if (tgid && nr) {
2131                 pos = find_task_by_pid(tgid);
2132                 if (pos && thread_group_leader(pos))
2133                         goto found;
2134         }
2135         /* If nr exceeds the number of processes get out quickly */
2136         pos = NULL;
2137         if (nr && nr >= nr_processes())
2138                 goto done;
2139
2140         /* If we haven't found our starting place yet start with
2141          * the init_task and walk nr tasks forward.
2142          */
2143         for (pos = next_task(&init_task); nr > 0; --nr) {
2144                 pos = next_task(pos);
2145                 if (pos == &init_task) {
2146                         pos = NULL;
2147                         goto done;
2148                 }
2149         }
2150 found:
2151         get_task_struct(pos);
2152 done:
2153         rcu_read_unlock();
2154         return pos;
2155 }
2156
2157 /*
2158  * Find the next task in the task list.
2159  * Return NULL if we loop or there is any error.
2160  *
2161  * The reference to the input task_struct is released.
2162  */
2163 static struct task_struct *next_tgid(struct task_struct *start)
2164 {
2165         struct task_struct *pos;
2166         rcu_read_lock();
2167         pos = start;
2168         if (pid_alive(start))
2169                 pos = next_task(start);
2170         if (pid_alive(pos) && (pos != &init_task)) {
2171                 get_task_struct(pos);
2172                 goto done;
2173         }
2174         pos = NULL;
2175 done:
2176         rcu_read_unlock();
2177         put_task_struct(start);
2178         return pos;
2179 }
2180
2181 /* for the /proc/ directory itself, after non-process stuff has been done */
2182 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2183 {
2184         char buf[PROC_NUMBUF];
2185         unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2186         struct task_struct *task;
2187         int tgid;
2188
2189         if (!nr) {
2190                 ino_t ino = fake_ino(0,PROC_TGID_INO);
2191                 if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
2192                         return 0;
2193                 filp->f_pos++;
2194                 nr++;
2195         }
2196         nr -= 1;
2197
2198         /* f_version caches the tgid value that the last readdir call couldn't
2199          * return. lseek aka telldir automagically resets f_version to 0.
2200          */
2201         tgid = filp->f_version;
2202         filp->f_version = 0;
2203         for (task = first_tgid(tgid, nr);
2204              task;
2205              task = next_tgid(task), filp->f_pos++) {
2206                 int len;
2207                 ino_t ino;
2208                 tgid = task->pid;
2209                 len = snprintf(buf, sizeof(buf), "%d", tgid);
2210                 ino = fake_ino(tgid, PROC_TGID_INO);
2211                 if (filldir(dirent, buf, len, filp->f_pos, ino, DT_DIR) < 0) {
2212                         /* returning this tgid failed, save it as the first
2213                          * pid for the next readir call */
2214                         filp->f_version = tgid;
2215                         put_task_struct(task);
2216                         break;
2217                 }
2218         }
2219         return 0;
2220 }
2221
2222 /*
2223  * Find the first tid of a thread group to return to user space.
2224  *
2225  * Usually this is just the thread group leader, but if the users
2226  * buffer was too small or there was a seek into the middle of the
2227  * directory we have more work todo.
2228  *
2229  * In the case of a short read we start with find_task_by_pid.
2230  *
2231  * In the case of a seek we start with the leader and walk nr
2232  * threads past it.
2233  */
2234 static struct task_struct *first_tid(struct task_struct *leader,
2235                                         int tid, int nr)
2236 {
2237         struct task_struct *pos;
2238
2239         rcu_read_lock();
2240         /* Attempt to start with the pid of a thread */
2241         if (tid && (nr > 0)) {
2242                 pos = find_task_by_pid(tid);
2243                 if (pos && (pos->group_leader == leader))
2244                         goto found;
2245         }
2246
2247         /* If nr exceeds the number of threads there is nothing todo */
2248         pos = NULL;
2249         if (nr && nr >= get_nr_threads(leader))
2250                 goto out;
2251
2252         /* If we haven't found our starting place yet start
2253          * with the leader and walk nr threads forward.
2254          */
2255         for (pos = leader; nr > 0; --nr) {
2256                 pos = next_thread(pos);
2257                 if (pos == leader) {
2258                         pos = NULL;
2259                         goto out;
2260                 }
2261         }
2262 found:
2263         get_task_struct(pos);
2264 out:
2265         rcu_read_unlock();
2266         return pos;
2267 }
2268
2269 /*
2270  * Find the next thread in the thread list.
2271  * Return NULL if there is an error or no next thread.
2272  *
2273  * The reference to the input task_struct is released.
2274  */
2275 static struct task_struct *next_tid(struct task_struct *start)
2276 {
2277         struct task_struct *pos = NULL;
2278         rcu_read_lock();
2279         if (pid_alive(start)) {
2280                 pos = next_thread(start);
2281                 if (thread_group_leader(pos))
2282                         pos = NULL;
2283                 else
2284                         get_task_struct(pos);
2285         }
2286         rcu_read_unlock();
2287         put_task_struct(start);
2288         return pos;
2289 }
2290
2291 /* for the /proc/TGID/task/ directories */
2292 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
2293 {
2294         char buf[PROC_NUMBUF];
2295         struct dentry *dentry = filp->f_dentry;
2296         struct inode *inode = dentry->d_inode;
2297         struct task_struct *leader = get_proc_task(inode);
2298         struct task_struct *task;
2299         int retval = -ENOENT;
2300         ino_t ino;
2301         int tid;
2302         unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
2303
2304         if (!leader)
2305                 goto out_no_task;
2306         retval = 0;
2307
2308         switch (pos) {
2309         case 0:
2310                 ino = inode->i_ino;
2311                 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
2312                         goto out;
2313                 pos++;
2314                 /* fall through */
2315         case 1:
2316                 ino = parent_ino(dentry);
2317                 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
2318                         goto out;
2319                 pos++;
2320                 /* fall through */
2321         }
2322
2323         /* f_version caches the tgid value that the last readdir call couldn't
2324          * return. lseek aka telldir automagically resets f_version to 0.
2325          */
2326         tid = filp->f_version;
2327         filp->f_version = 0;
2328         for (task = first_tid(leader, tid, pos - 2);
2329              task;
2330              task = next_tid(task), pos++) {
2331                 int len;
2332                 tid = task->pid;
2333                 len = snprintf(buf, sizeof(buf), "%d", tid);
2334                 ino = fake_ino(tid, PROC_TID_INO);
2335                 if (filldir(dirent, buf, len, pos, ino, DT_DIR < 0)) {
2336                         /* returning this tgid failed, save it as the first
2337                          * pid for the next readir call */
2338                         filp->f_version = tid;
2339                         put_task_struct(task);
2340                         break;
2341                 }
2342         }
2343 out:
2344         filp->f_pos = pos;
2345         put_task_struct(leader);
2346 out_no_task:
2347         return retval;
2348 }
2349
2350 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
2351 {
2352         struct inode *inode = dentry->d_inode;
2353         struct task_struct *p = get_proc_task(inode);
2354         generic_fillattr(inode, stat);
2355
2356         if (p) {
2357                 rcu_read_lock();
2358                 stat->nlink += get_nr_threads(p);
2359                 rcu_read_unlock();
2360                 put_task_struct(p);
2361         }
2362
2363         return 0;
2364 }