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 static int proc_setattr(struct dentry *dentry, struct iattr *attr)
 555 {
 556         int error;
 557         struct inode *inode = dentry->d_inode;
 558
 559         if (attr->ia_valid & ATTR_MODE)
 560                 return -EPERM;
 561
 562         error = inode_change_ok(inode, attr);
 563         if (!error) {
 564                 error = security_inode_setattr(dentry, attr);
 565                 if (!error)
 566                         error = inode_setattr(inode, attr);
 567         }
 568         return error;
 569 }
 570
 571 static struct inode_operations proc_def_inode_operations = {
 572         .setattr        = proc_setattr,
 573 };
 574
 575 extern struct seq_operations mounts_op;
 576 struct proc_mounts {
 577         struct seq_file m;
 578         int event;
 579 };
 580
 581 static int mounts_open(struct inode *inode, struct file *file)
 582 {
 583         struct task_struct *task = get_proc_task(inode);
 584         struct namespace *namespace = NULL;
 585         struct proc_mounts *p;
 586         int ret = -EINVAL;
 587
 588         if (task) {
 589                 task_lock(task);
 590                 namespace = task->namespace;
 591                 if (namespace)
 592                         get_namespace(namespace);
 593                 task_unlock(task);
 594                 put_task_struct(task);
 595         }
 596
 597         if (namespace) {
 598                 ret = -ENOMEM;
 599                 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
 600                 if (p) {
 601                         file->private_data = &p->m;
 602                         ret = seq_open(file, &mounts_op);
 603                         if (!ret) {
 604                                 p->m.private = namespace;
 605                                 p->event = namespace->event;
 606                                 return 0;
 607                         }
 608                         kfree(p);
 609                 }
 610                 put_namespace(namespace);
 611         }
 612         return ret;
 613 }
 614
 615 static int mounts_release(struct inode *inode, struct file *file)
 616 {
 617         struct seq_file *m = file->private_data;
 618         struct namespace *namespace = m->private;
 619         put_namespace(namespace);
 620         return seq_release(inode, file);
 621 }
 622
 623 static unsigned mounts_poll(struct file *file, poll_table *wait)
 624 {
 625         struct proc_mounts *p = file->private_data;
 626         struct namespace *ns = p->m.private;
 627         unsigned res = 0;
 628
 629         poll_wait(file, &ns->poll, wait);
 630
 631         spin_lock(&vfsmount_lock);
 632         if (p->event != ns->event) {
 633                 p->event = ns->event;
 634                 res = POLLERR;
 635         }
 636         spin_unlock(&vfsmount_lock);
 637
 638         return res;
 639 }
 640
 641 static struct file_operations proc_mounts_operations = {
 642         .open           = mounts_open,
 643         .read           = seq_read,
 644         .llseek         = seq_lseek,
 645         .release        = mounts_release,
 646         .poll           = mounts_poll,
 647 };
 648
 649 extern struct seq_operations mountstats_op;
 650 static int mountstats_open(struct inode *inode, struct file *file)
 651 {
 652         int ret = seq_open(file, &mountstats_op);
 653
 654         if (!ret) {
 655                 struct seq_file *m = file->private_data;
 656                 struct namespace *namespace = NULL;
 657                 struct task_struct *task = get_proc_task(inode);
 658
 659                 if (task) {
 660                         task_lock(task);
 661                         namespace = task->namespace;
 662                         if (namespace)
 663                                 get_namespace(namespace);
 664                         task_unlock(task);
 665                         put_task_struct(task);
 666                 }
 667
 668                 if (namespace)
 669                         m->private = namespace;
 670                 else {
 671                         seq_release(inode, file);
 672                         ret = -EINVAL;
 673                 }
 674         }
 675         return ret;
 676 }
 677
 678 static struct file_operations proc_mountstats_operations = {
 679         .open           = mountstats_open,
 680         .read           = seq_read,
 681         .llseek         = seq_lseek,
 682         .release        = mounts_release,
 683 };
 684
 685 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 686
 687 static ssize_t proc_info_read(struct file * file, char __user * buf,
 688                           size_t count, loff_t *ppos)
 689 {
 690         struct inode * inode = file->f_dentry->d_inode;
 691         unsigned long page;
 692         ssize_t length;
 693         struct task_struct *task = get_proc_task(inode);
 694
 695         length = -ESRCH;
 696         if (!task)
 697                 goto out_no_task;
 698
 699         if (count > PROC_BLOCK_SIZE)
 700                 count = PROC_BLOCK_SIZE;
 701
 702         length = -ENOMEM;
 703         if (!(page = __get_free_page(GFP_KERNEL)))
 704                 goto out;
 705
 706         length = PROC_I(inode)->op.proc_read(task, (char*)page);
 707
 708         if (length >= 0)
 709                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 710         free_page(page);
 711 out:
 712         put_task_struct(task);
 713 out_no_task:
 714         return length;
 715 }
 716
 717 static struct file_operations proc_info_file_operations = {
 718         .read           = proc_info_read,
 719 };
 720
 721 static int mem_open(struct inode* inode, struct file* file)
 722 {
 723         file->private_data = (void*)((long)current->self_exec_id);
 724         return 0;
 725 }
 726
 727 static ssize_t mem_read(struct file * file, char __user * buf,
 728                         size_t count, loff_t *ppos)
 729 {
 730         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 731         char *page;
 732         unsigned long src = *ppos;
 733         int ret = -ESRCH;
 734         struct mm_struct *mm;
 735
 736         if (!task)
 737                 goto out_no_task;
 738
 739         if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
 740                 goto out;
 741
 742         ret = -ENOMEM;
 743         page = (char *)__get_free_page(GFP_USER);
 744         if (!page)
 745                 goto out;
 746
 747         ret = 0;
 748
 749         mm = get_task_mm(task);
 750         if (!mm)
 751                 goto out_free;
 752
 753         ret = -EIO;
 754
 755         if (file->private_data != (void*)((long)current->self_exec_id))
 756                 goto out_put;
 757
 758         ret = 0;
 759
 760         while (count > 0) {
 761                 int this_len, retval;
 762
 763                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 764                 retval = access_process_vm(task, src, page, this_len, 0);
 765                 if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
 766                         if (!ret)
 767                                 ret = -EIO;
 768                         break;
 769                 }
 770
 771                 if (copy_to_user(buf, page, retval)) {
 772                         ret = -EFAULT;
 773                         break;
 774                 }
 775
 776                 ret += retval;
 777                 src += retval;
 778                 buf += retval;
 779                 count -= retval;
 780         }
 781         *ppos = src;
 782
 783 out_put:
 784         mmput(mm);
 785 out_free:
 786         free_page((unsigned long) page);
 787 out:
 788         put_task_struct(task);
 789 out_no_task:
 790         return ret;
 791 }
 792
 793 #define mem_write NULL
 794
 795 #ifndef mem_write
 796 /* This is a security hazard */
 797 static ssize_t mem_write(struct file * file, const char * buf,
 798                          size_t count, loff_t *ppos)
 799 {
 800         int copied = 0;
 801         char *page;
 802         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 803         unsigned long dst = *ppos;
 804
 805         copied = -ESRCH;
 806         if (!task)
 807                 goto out_no_task;
 808
 809         if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
 810                 goto out;
 811
 812         copied = -ENOMEM;
 813         page = (char *)__get_free_page(GFP_USER);
 814         if (!page)
 815                 goto out;
 816
 817         while (count > 0) {
 818                 int this_len, retval;
 819
 820                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 821                 if (copy_from_user(page, buf, this_len)) {
 822                         copied = -EFAULT;
 823                         break;
 824                 }
 825                 retval = access_process_vm(task, dst, page, this_len, 1);
 826                 if (!retval) {
 827                         if (!copied)
 828                                 copied = -EIO;
 829                         break;
 830                 }
 831                 copied += retval;
 832                 buf += retval;
 833                 dst += retval;
 834                 count -= retval;
 835         }
 836         *ppos = dst;
 837         free_page((unsigned long) page);
 838 out:
 839         put_task_struct(task);
 840 out_no_task:
 841         return copied;
 842 }
 843 #endif
 844
 845 static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
 846 {
 847         switch (orig) {
 848         case 0:
 849                 file->f_pos = offset;
 850                 break;
 851         case 1:
 852                 file->f_pos += offset;
 853                 break;
 854         default:
 855                 return -EINVAL;
 856         }
 857         force_successful_syscall_return();
 858         return file->f_pos;
 859 }
 860
 861 static struct file_operations proc_mem_operations = {
 862         .llseek         = mem_lseek,
 863         .read           = mem_read,
 864         .write          = mem_write,
 865         .open           = mem_open,
 866 };
 867
 868 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
 869                                 size_t count, loff_t *ppos)
 870 {
 871         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 872         char buffer[PROC_NUMBUF];
 873         size_t len;
 874         int oom_adjust;
 875         loff_t __ppos = *ppos;
 876
 877         if (!task)
 878                 return -ESRCH;
 879         oom_adjust = task->oomkilladj;
 880         put_task_struct(task);
 881
 882         len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
 883         if (__ppos >= len)
 884                 return 0;
 885         if (count > len-__ppos)
 886                 count = len-__ppos;
 887         if (copy_to_user(buf, buffer + __ppos, count))
 888                 return -EFAULT;
 889         *ppos = __ppos + count;
 890         return count;
 891 }
 892
 893 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 894                                 size_t count, loff_t *ppos)
 895 {
 896         struct task_struct *task;
 897         char buffer[PROC_NUMBUF], *end;
 898         int oom_adjust;
 899
 900         if (!capable(CAP_SYS_RESOURCE))
 901                 return -EPERM;
 902         memset(buffer, 0, sizeof(buffer));
 903         if (count > sizeof(buffer) - 1)
 904                 count = sizeof(buffer) - 1;
 905         if (copy_from_user(buffer, buf, count))
 906                 return -EFAULT;
 907         oom_adjust = simple_strtol(buffer, &end, 0);
 908         if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
 909                 return -EINVAL;
 910         if (*end == '\n')
 911                 end++;
 912         task = get_proc_task(file->f_dentry->d_inode);
 913         if (!task)
 914                 return -ESRCH;
 915         task->oomkilladj = oom_adjust;
 916         put_task_struct(task);
 917         if (end - buffer == 0)
 918                 return -EIO;
 919         return end - buffer;
 920 }
 921
 922 static struct file_operations proc_oom_adjust_operations = {
 923         .read           = oom_adjust_read,
 924         .write          = oom_adjust_write,
 925 };
 926
 927 #ifdef CONFIG_AUDITSYSCALL
 928 #define TMPBUFLEN 21
 929 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
 930                                   size_t count, loff_t *ppos)
 931 {
 932         struct inode * inode = file->f_dentry->d_inode;
 933         struct task_struct *task = get_proc_task(inode);
 934         ssize_t length;
 935         char tmpbuf[TMPBUFLEN];
 936
 937         if (!task)
 938                 return -ESRCH;
 939         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
 940                                 audit_get_loginuid(task->audit_context));
 941         put_task_struct(task);
 942         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 943 }
 944
 945 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 946                                    size_t count, loff_t *ppos)
 947 {
 948         struct inode * inode = file->f_dentry->d_inode;
 949         char *page, *tmp;
 950         ssize_t length;
 951         uid_t loginuid;
 952
 953         if (!capable(CAP_AUDIT_CONTROL))
 954                 return -EPERM;
 955
 956         if (current != pid_task(proc_pid(inode), PIDTYPE_PID))
 957                 return -EPERM;
 958
 959         if (count >= PAGE_SIZE)
 960                 count = PAGE_SIZE - 1;
 961
 962         if (*ppos != 0) {
 963                 /* No partial writes. */
 964                 return -EINVAL;
 965         }
 966         page = (char*)__get_free_page(GFP_USER);
 967         if (!page)
 968                 return -ENOMEM;
 969         length = -EFAULT;
 970         if (copy_from_user(page, buf, count))
 971                 goto out_free_page;
 972
 973         page[count] = '\0';
 974         loginuid = simple_strtoul(page, &tmp, 10);
 975         if (tmp == page) {
 976                 length = -EINVAL;
 977                 goto out_free_page;
 978
 979         }
 980         length = audit_set_loginuid(current, loginuid);
 981         if (likely(length == 0))
 982                 length = count;
 983
 984 out_free_page:
 985         free_page((unsigned long) page);
 986         return length;
 987 }
 988
 989 static struct file_operations proc_loginuid_operations = {
 990         .read           = proc_loginuid_read,
 991         .write          = proc_loginuid_write,
 992 };
 993 #endif
 994
 995 #ifdef CONFIG_SECCOMP
 996 static ssize_t seccomp_read(struct file *file, char __user *buf,
 997                             size_t count, loff_t *ppos)
 998 {
 999         struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode);
1000         char __buf[20];
1001         loff_t __ppos = *ppos;
1002         size_t len;
1003
1004         if (!tsk)
1005                 return -ESRCH;
1006         /* no need to print the trailing zero, so use only len */
1007         len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
1008         put_task_struct(tsk);
1009         if (__ppos >= len)
1010                 return 0;
1011         if (count > len - __ppos)
1012                 count = len - __ppos;
1013         if (copy_to_user(buf, __buf + __ppos, count))
1014                 return -EFAULT;
1015         *ppos = __ppos + count;
1016         return count;
1017 }
1018
1019 static ssize_t seccomp_write(struct file *file, const char __user *buf,
1020                              size_t count, loff_t *ppos)
1021 {
1022         struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode);
1023         char __buf[20], *end;
1024         unsigned int seccomp_mode;
1025         ssize_t result;
1026
1027         result = -ESRCH;
1028         if (!tsk)
1029                 goto out_no_task;
1030
1031         /* can set it only once to be even more secure */
1032         result = -EPERM;
1033         if (unlikely(tsk->seccomp.mode))
1034                 goto out;
1035
1036         result = -EFAULT;
1037         memset(__buf, 0, sizeof(__buf));
1038         count = min(count, sizeof(__buf) - 1);
1039         if (copy_from_user(__buf, buf, count))
1040                 goto out;
1041
1042         seccomp_mode = simple_strtoul(__buf, &end, 0);
1043         if (*end == '\n')
1044                 end++;
1045         result = -EINVAL;
1046         if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
1047                 tsk->seccomp.mode = seccomp_mode;
1048                 set_tsk_thread_flag(tsk, TIF_SECCOMP);
1049         } else
1050                 goto out;
1051         result = -EIO;
1052         if (unlikely(!(end - __buf)))
1053                 goto out;
1054         result = end - __buf;
1055 out:
1056         put_task_struct(tsk);
1057 out_no_task:
1058         return result;
1059 }
1060
1061 static struct file_operations proc_seccomp_operations = {
1062         .read           = seccomp_read,
1063         .write          = seccomp_write,
1064 };
1065 #endif /* CONFIG_SECCOMP */
1066
1067 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1068 {
1069         struct inode *inode = dentry->d_inode;
1070         int error = -EACCES;
1071
1072         /* We don't need a base pointer in the /proc filesystem */
1073         path_release(nd);
1074
1075         /* Are we allowed to snoop on the tasks file descriptors? */
1076         if (!proc_fd_access_allowed(inode))
1077                 goto out;
1078
1079         error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
1080         nd->last_type = LAST_BIND;
1081 out:
1082         return ERR_PTR(error);
1083 }
1084
1085 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
1086                             char __user *buffer, int buflen)
1087 {
1088         struct inode * inode;
1089         char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
1090         int len;
1091
1092         if (!tmp)
1093                 return -ENOMEM;
1094
1095         inode = dentry->d_inode;
1096         path = d_path(dentry, mnt, tmp, PAGE_SIZE);
1097         len = PTR_ERR(path);
1098         if (IS_ERR(path))
1099                 goto out;
1100         len = tmp + PAGE_SIZE - 1 - path;
1101
1102         if (len > buflen)
1103                 len = buflen;
1104         if (copy_to_user(buffer, path, len))
1105                 len = -EFAULT;
1106  out:
1107         free_page((unsigned long)tmp);
1108         return len;
1109 }
1110
1111 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1112 {
1113         int error = -EACCES;
1114         struct inode *inode = dentry->d_inode;
1115         struct dentry *de;
1116         struct vfsmount *mnt = NULL;
1117
1118         /* Are we allowed to snoop on the tasks file descriptors? */
1119         if (!proc_fd_access_allowed(inode))
1120                 goto out;
1121
1122         error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
1123         if (error)
1124                 goto out;
1125
1126         error = do_proc_readlink(de, mnt, buffer, buflen);
1127         dput(de);
1128         mntput(mnt);
1129 out:
1130         return error;
1131 }
1132
1133 static struct inode_operations proc_pid_link_inode_operations = {
1134         .readlink       = proc_pid_readlink,
1135         .follow_link    = proc_pid_follow_link,
1136         .setattr        = proc_setattr,
1137 };
1138
1139 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
1140 {
1141         struct dentry *dentry = filp->f_dentry;
1142         struct inode *inode = dentry->d_inode;
1143         struct task_struct *p = get_proc_task(inode);
1144         unsigned int fd, tid, ino;
1145         int retval;
1146         char buf[PROC_NUMBUF];
1147         struct files_struct * files;
1148         struct fdtable *fdt;
1149
1150         retval = -ENOENT;
1151         if (!p)
1152                 goto out_no_task;
1153         retval = 0;
1154         tid = p->pid;
1155
1156         fd = filp->f_pos;
1157         switch (fd) {
1158                 case 0:
1159                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1160                                 goto out;
1161                         filp->f_pos++;
1162                 case 1:
1163                         ino = parent_ino(dentry);
1164                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1165                                 goto out;
1166                         filp->f_pos++;
1167                 default:
1168                         files = get_files_struct(p);
1169                         if (!files)
1170                                 goto out;
1171                         rcu_read_lock();
1172                         fdt = files_fdtable(files);
1173                         for (fd = filp->f_pos-2;
1174                              fd < fdt->max_fds;
1175                              fd++, filp->f_pos++) {
1176                                 unsigned int i,j;
1177
1178                                 if (!fcheck_files(files, fd))
1179                                         continue;
1180                                 rcu_read_unlock();
1181
1182                                 j = PROC_NUMBUF;
1183                                 i = fd;
1184                                 do {
1185                                         j--;
1186                                         buf[j] = '0' + (i % 10);
1187                                         i /= 10;
1188                                 } while (i);
1189
1190                                 ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
1191                                 if (filldir(dirent, buf+j, PROC_NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
1192                                         rcu_read_lock();
1193                                         break;
1194                                 }
1195                                 rcu_read_lock();
1196                         }
1197                         rcu_read_unlock();
1198                         put_files_struct(files);
1199         }
1200 out:
1201         put_task_struct(p);
1202 out_no_task:
1203         return retval;
1204 }
1205
1206 static int proc_pident_readdir(struct file *filp,
1207                 void *dirent, filldir_t filldir,
1208                 struct pid_entry *ents, unsigned int nents)
1209 {
1210         int i;
1211         int pid;
1212         struct dentry *dentry = filp->f_dentry;
1213         struct inode *inode = dentry->d_inode;
1214         struct task_struct *task = get_proc_task(inode);
1215         struct pid_entry *p;
1216         ino_t ino;
1217         int ret;
1218
1219         ret = -ENOENT;
1220         if (!task)
1221                 goto out;
1222
1223         ret = 0;
1224         pid = task->pid;
1225         put_task_struct(task);
1226         i = filp->f_pos;
1227         switch (i) {
1228         case 0:
1229                 ino = inode->i_ino;
1230                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1231                         goto out;
1232                 i++;
1233                 filp->f_pos++;
1234                 /* fall through */
1235         case 1:
1236                 ino = parent_ino(dentry);
1237                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1238                         goto out;
1239                 i++;
1240                 filp->f_pos++;
1241                 /* fall through */
1242         default:
1243                 i -= 2;
1244                 if (i >= nents) {
1245                         ret = 1;
1246                         goto out;
1247                 }
1248                 p = ents + i;
1249                 while (p->name) {
1250                         if (filldir(dirent, p->name, p->len, filp->f_pos,
1251                                     fake_ino(pid, p->type), p->mode >> 12) < 0)
1252                                 goto out;
1253                         filp->f_pos++;
1254                         p++;
1255                 }
1256         }
1257
1258         ret = 1;
1259 out:
1260         return ret;
1261 }
1262
1263 static int proc_tgid_base_readdir(struct file * filp,
1264                              void * dirent, filldir_t filldir)
1265 {
1266         return proc_pident_readdir(filp,dirent,filldir,
1267                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
1268 }
1269
1270 static int proc_tid_base_readdir(struct file * filp,
1271                              void * dirent, filldir_t filldir)
1272 {
1273         return proc_pident_readdir(filp,dirent,filldir,
1274                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
1275 }
1276
1277 /* building an inode */
1278
1279 static int task_dumpable(struct task_struct *task)
1280 {
1281         int dumpable = 0;
1282         struct mm_struct *mm;
1283
1284         task_lock(task);
1285         mm = task->mm;
1286         if (mm)
1287                 dumpable = mm->dumpable;
1288         task_unlock(task);
1289         if(dumpable == 1)
1290                 return 1;
1291         return 0;
1292 }
1293
1294
1295 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
1296 {
1297         struct inode * inode;
1298         struct proc_inode *ei;
1299
1300         /* We need a new inode */
1301
1302         inode = new_inode(sb);
1303         if (!inode)
1304                 goto out;
1305
1306         /* Common stuff */
1307         ei = PROC_I(inode);
1308         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1309         inode->i_ino = fake_ino(task->pid, ino);
1310         inode->i_op = &proc_def_inode_operations;
1311
1312         /*
1313          * grab the reference to task.
1314          */
1315         ei->pid = get_pid(task->pids[PIDTYPE_PID].pid);
1316         if (!ei->pid)
1317                 goto out_unlock;
1318
1319         inode->i_uid = 0;
1320         inode->i_gid = 0;
1321         if (task_dumpable(task)) {
1322                 inode->i_uid = task->euid;
1323                 inode->i_gid = task->egid;
1324         }
1325         security_task_to_inode(task, inode);
1326
1327 out:
1328         return inode;
1329
1330 out_unlock:
1331         iput(inode);
1332         return NULL;
1333 }
1334
1335 /* dentry stuff */
1336
1337 /*
1338  *      Exceptional case: normally we are not allowed to unhash a busy
1339  * directory. In this case, however, we can do it - no aliasing problems
1340  * due to the way we treat inodes.
1341  *
1342  * Rewrite the inode's ownerships here because the owning task may have
1343  * performed a setuid(), etc.
1344  *
1345  * Before the /proc/pid/status file was created the only way to read
1346  * the effective uid of a /process was to stat /proc/pid.  Reading
1347  * /proc/pid/status is slow enough that procps and other packages
1348  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1349  * made this apply to all per process world readable and executable
1350  * directories.
1351  */
1352 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1353 {
1354         struct inode *inode = dentry->d_inode;
1355         struct task_struct *task = get_proc_task(inode);
1356         if (task) {
1357                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1358                     task_dumpable(task)) {
1359                         inode->i_uid = task->euid;
1360                         inode->i_gid = task->egid;
1361                 } else {
1362                         inode->i_uid = 0;
1363                         inode->i_gid = 0;
1364                 }
1365                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1366                 security_task_to_inode(task, inode);
1367                 put_task_struct(task);
1368                 return 1;
1369         }
1370         d_drop(dentry);
1371         return 0;
1372 }
1373
1374 static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1375 {
1376         struct inode *inode = dentry->d_inode;
1377         struct task_struct *task;
1378         generic_fillattr(inode, stat);
1379
1380         rcu_read_lock();
1381         stat->uid = 0;
1382         stat->gid = 0;
1383         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1384         if (task) {
1385                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1386                     task_dumpable(task)) {
1387                         stat->uid = task->euid;
1388                         stat->gid = task->egid;
1389                 }
1390         }
1391         rcu_read_unlock();
1392         return 0;
1393 }
1394
1395 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1396 {
1397         struct inode *inode = dentry->d_inode;
1398         struct task_struct *task = get_proc_task(inode);
1399         int fd = proc_fd(inode);
1400         struct files_struct *files;
1401
1402         if (task) {
1403                 files = get_files_struct(task);
1404                 if (files) {
1405                         rcu_read_lock();
1406                         if (fcheck_files(files, fd)) {
1407                                 rcu_read_unlock();
1408                                 put_files_struct(files);
1409                                 if (task_dumpable(task)) {
1410                                         inode->i_uid = task->euid;
1411                                         inode->i_gid = task->egid;
1412                                 } else {
1413                                         inode->i_uid = 0;
1414                                         inode->i_gid = 0;
1415                                 }
1416                                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1417                                 security_task_to_inode(task, inode);
1418                                 put_task_struct(task);
1419                                 return 1;
1420                         }
1421                         rcu_read_unlock();
1422                         put_files_struct(files);
1423                 }
1424                 put_task_struct(task);
1425         }
1426         d_drop(dentry);
1427         return 0;
1428 }
1429
1430 static int pid_delete_dentry(struct dentry * dentry)
1431 {
1432         /* Is the task we represent dead?
1433          * If so, then don't put the dentry on the lru list,
1434          * kill it immediately.
1435          */
1436         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1437 }
1438
1439 static struct dentry_operations tid_fd_dentry_operations =
1440 {
1441         .d_revalidate   = tid_fd_revalidate,
1442         .d_delete       = pid_delete_dentry,
1443 };
1444
1445 static struct dentry_operations pid_dentry_operations =
1446 {
1447         .d_revalidate   = pid_revalidate,
1448         .d_delete       = pid_delete_dentry,
1449 };
1450
1451 /* Lookups */
1452
1453 static unsigned name_to_int(struct dentry *dentry)
1454 {
1455         const char *name = dentry->d_name.name;
1456         int len = dentry->d_name.len;
1457         unsigned n = 0;
1458
1459         if (len > 1 && *name == '0')
1460                 goto out;
1461         while (len-- > 0) {
1462                 unsigned c = *name++ - '0';
1463                 if (c > 9)
1464                         goto out;
1465                 if (n >= (~0U-9)/10)
1466                         goto out;
1467                 n *= 10;
1468                 n += c;
1469         }
1470         return n;
1471 out:
1472         return ~0U;
1473 }
1474
1475 /* SMP-safe */
1476 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
1477 {
1478         struct task_struct *task = get_proc_task(dir);
1479         unsigned fd = name_to_int(dentry);
1480         struct dentry *result = ERR_PTR(-ENOENT);
1481         struct file * file;
1482         struct files_struct * files;
1483         struct inode *inode;
1484         struct proc_inode *ei;
1485
1486         if (!task)
1487                 goto out_no_task;
1488         if (fd == ~0U)
1489                 goto out;
1490
1491         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
1492         if (!inode)
1493                 goto out;
1494         ei = PROC_I(inode);
1495         ei->fd = fd;
1496         files = get_files_struct(task);
1497         if (!files)
1498                 goto out_unlock;
1499         inode->i_mode = S_IFLNK;
1500
1501         /*
1502          * We are not taking a ref to the file structure, so we must
1503          * hold ->file_lock.
1504          */
1505         spin_lock(&files->file_lock);
1506         file = fcheck_files(files, fd);
1507         if (!file)
1508                 goto out_unlock2;
1509         if (file->f_mode & 1)
1510                 inode->i_mode |= S_IRUSR | S_IXUSR;
1511         if (file->f_mode & 2)
1512                 inode->i_mode |= S_IWUSR | S_IXUSR;
1513         spin_unlock(&files->file_lock);
1514         put_files_struct(files);
1515         inode->i_op = &proc_pid_link_inode_operations;
1516         inode->i_size = 64;
1517         ei->op.proc_get_link = proc_fd_link;
1518         dentry->d_op = &tid_fd_dentry_operations;
1519         d_add(dentry, inode);
1520         /* Close the race of the process dying before we return the dentry */
1521         if (tid_fd_revalidate(dentry, NULL))
1522                 result = NULL;
1523 out:
1524         put_task_struct(task);
1525 out_no_task:
1526         return result;
1527
1528 out_unlock2:
1529         spin_unlock(&files->file_lock);
1530         put_files_struct(files);
1531 out_unlock:
1532         iput(inode);
1533         goto out;
1534 }
1535
1536 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
1537 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
1538 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat);
1539
1540 static struct file_operations proc_fd_operations = {
1541         .read           = generic_read_dir,
1542         .readdir        = proc_readfd,
1543 };
1544
1545 static struct file_operations proc_task_operations = {
1546         .read           = generic_read_dir,
1547         .readdir        = proc_task_readdir,
1548 };
1549
1550 /*
1551  * proc directories can do almost nothing..
1552  */
1553 static struct inode_operations proc_fd_inode_operations = {
1554         .lookup         = proc_lookupfd,
1555         .setattr        = proc_setattr,
1556 };
1557
1558 static struct inode_operations proc_task_inode_operations = {
1559         .lookup         = proc_task_lookup,
1560         .getattr        = proc_task_getattr,
1561         .setattr        = proc_setattr,
1562 };
1563
1564 #ifdef CONFIG_SECURITY
1565 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
1566                                   size_t count, loff_t *ppos)
1567 {
1568         struct inode * inode = file->f_dentry->d_inode;
1569         unsigned long page;
1570         ssize_t length;
1571         struct task_struct *task = get_proc_task(inode);
1572
1573         length = -ESRCH;
1574         if (!task)
1575                 goto out_no_task;
1576
1577         if (count > PAGE_SIZE)
1578                 count = PAGE_SIZE;
1579         length = -ENOMEM;
1580         if (!(page = __get_free_page(GFP_KERNEL)))
1581                 goto out;
1582
1583         length = security_getprocattr(task,
1584                                       (char*)file->f_dentry->d_name.name,
1585                                       (void*)page, count);
1586         if (length >= 0)
1587                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
1588         free_page(page);
1589 out:
1590         put_task_struct(task);
1591 out_no_task:
1592         return length;
1593 }
1594
1595 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
1596                                    size_t count, loff_t *ppos)
1597 {
1598         struct inode * inode = file->f_dentry->d_inode;
1599         char *page;
1600         ssize_t length;
1601         struct task_struct *task = get_proc_task(inode);
1602
1603         length = -ESRCH;
1604         if (!task)
1605                 goto out_no_task;
1606         if (count > PAGE_SIZE)
1607                 count = PAGE_SIZE;
1608
1609         /* No partial writes. */
1610         length = -EINVAL;
1611         if (*ppos != 0)
1612                 goto out;
1613
1614         length = -ENOMEM;
1615         page = (char*)__get_free_page(GFP_USER);
1616         if (!page)
1617                 goto out;
1618
1619         length = -EFAULT;
1620         if (copy_from_user(page, buf, count))
1621                 goto out_free;
1622
1623         length = security_setprocattr(task,
1624                                       (char*)file->f_dentry->d_name.name,
1625                                       (void*)page, count);
1626 out_free:
1627         free_page((unsigned long) page);
1628 out:
1629         put_task_struct(task);
1630 out_no_task:
1631         return length;
1632 }
1633
1634 static struct file_operations proc_pid_attr_operations = {
1635         .read           = proc_pid_attr_read,
1636         .write          = proc_pid_attr_write,
1637 };
1638
1639 static struct file_operations proc_tid_attr_operations;
1640 static struct inode_operations proc_tid_attr_inode_operations;
1641 static struct file_operations proc_tgid_attr_operations;
1642 static struct inode_operations proc_tgid_attr_inode_operations;
1643 #endif
1644
1645 /* SMP-safe */
1646 static struct dentry *proc_pident_lookup(struct inode *dir,
1647                                          struct dentry *dentry,
1648                                          struct pid_entry *ents)
1649 {
1650         struct inode *inode;
1651         struct dentry *error;
1652         struct task_struct *task = get_proc_task(dir);
1653         struct pid_entry *p;
1654         struct proc_inode *ei;
1655
1656         error = ERR_PTR(-ENOENT);
1657         inode = NULL;
1658
1659         if (!task)
1660                 goto out_no_task;
1661
1662         for (p = ents; p->name; p++) {
1663                 if (p->len != dentry->d_name.len)
1664                         continue;
1665                 if (!memcmp(dentry->d_name.name, p->name, p->len))
1666                         break;
1667         }
1668         if (!p->name)
1669                 goto out;
1670
1671         error = ERR_PTR(-EINVAL);
1672         inode = proc_pid_make_inode(dir->i_sb, task, p->type);
1673         if (!inode)
1674                 goto out;
1675
1676         ei = PROC_I(inode);
1677         inode->i_mode = p->mode;
1678         /*
1679          * Yes, it does not scale. And it should not. Don't add
1680          * new entries into /proc/<tgid>/ without very good reasons.
1681          */
1682         switch(p->type) {
1683                 case PROC_TGID_TASK:
1684                         inode->i_nlink = 2;
1685                         inode->i_op = &proc_task_inode_operations;
1686                         inode->i_fop = &proc_task_operations;
1687                         break;
1688                 case PROC_TID_FD:
1689                 case PROC_TGID_FD:
1690                         inode->i_nlink = 2;
1691                         inode->i_op = &proc_fd_inode_operations;
1692                         inode->i_fop = &proc_fd_operations;
1693                         break;
1694                 case PROC_TID_EXE:
1695                 case PROC_TGID_EXE:
1696                         inode->i_op = &proc_pid_link_inode_operations;
1697                         ei->op.proc_get_link = proc_exe_link;
1698                         break;
1699                 case PROC_TID_CWD:
1700                 case PROC_TGID_CWD:
1701                         inode->i_op = &proc_pid_link_inode_operations;
1702                         ei->op.proc_get_link = proc_cwd_link;
1703                         break;
1704                 case PROC_TID_ROOT:
1705                 case PROC_TGID_ROOT:
1706                         inode->i_op = &proc_pid_link_inode_operations;
1707                         ei->op.proc_get_link = proc_root_link;
1708                         break;
1709                 case PROC_TID_ENVIRON:
1710                 case PROC_TGID_ENVIRON:
1711                         inode->i_fop = &proc_info_file_operations;
1712                         ei->op.proc_read = proc_pid_environ;
1713                         break;
1714                 case PROC_TID_AUXV:
1715                 case PROC_TGID_AUXV:
1716                         inode->i_fop = &proc_info_file_operations;
1717                         ei->op.proc_read = proc_pid_auxv;
1718                         break;
1719                 case PROC_TID_STATUS:
1720                 case PROC_TGID_STATUS:
1721                         inode->i_fop = &proc_info_file_operations;
1722                         ei->op.proc_read = proc_pid_status;
1723                         break;
1724                 case PROC_TID_STAT:
1725                         inode->i_fop = &proc_info_file_operations;
1726                         ei->op.proc_read = proc_tid_stat;
1727                         break;
1728                 case PROC_TGID_STAT:
1729                         inode->i_fop = &proc_info_file_operations;
1730                         ei->op.proc_read = proc_tgid_stat;
1731                         break;
1732                 case PROC_TID_CMDLINE:
1733                 case PROC_TGID_CMDLINE:
1734                         inode->i_fop = &proc_info_file_operations;
1735                         ei->op.proc_read = proc_pid_cmdline;
1736                         break;
1737                 case PROC_TID_STATM:
1738                 case PROC_TGID_STATM:
1739                         inode->i_fop = &proc_info_file_operations;
1740                         ei->op.proc_read = proc_pid_statm;
1741                         break;
1742                 case PROC_TID_MAPS:
1743                 case PROC_TGID_MAPS:
1744                         inode->i_fop = &proc_maps_operations;
1745                         break;
1746 #ifdef CONFIG_NUMA
1747                 case PROC_TID_NUMA_MAPS:
1748                 case PROC_TGID_NUMA_MAPS:
1749                         inode->i_fop = &proc_numa_maps_operations;
1750                         break;
1751 #endif
1752                 case PROC_TID_MEM:
1753                 case PROC_TGID_MEM:
1754                         inode->i_fop = &proc_mem_operations;
1755                         break;
1756 #ifdef CONFIG_SECCOMP
1757                 case PROC_TID_SECCOMP:
1758                 case PROC_TGID_SECCOMP:
1759                         inode->i_fop = &proc_seccomp_operations;
1760                         break;
1761 #endif /* CONFIG_SECCOMP */
1762                 case PROC_TID_MOUNTS:
1763                 case PROC_TGID_MOUNTS:
1764                         inode->i_fop = &proc_mounts_operations;
1765                         break;
1766 #ifdef CONFIG_MMU
1767                 case PROC_TID_SMAPS:
1768                 case PROC_TGID_SMAPS:
1769                         inode->i_fop = &proc_smaps_operations;
1770                         break;
1771 #endif
1772                 case PROC_TID_MOUNTSTATS:
1773                 case PROC_TGID_MOUNTSTATS:
1774                         inode->i_fop = &proc_mountstats_operations;
1775                         break;
1776 #ifdef CONFIG_SECURITY
1777                 case PROC_TID_ATTR:
1778                         inode->i_nlink = 2;
1779                         inode->i_op = &proc_tid_attr_inode_operations;
1780                         inode->i_fop = &proc_tid_attr_operations;
1781                         break;
1782                 case PROC_TGID_ATTR:
1783                         inode->i_nlink = 2;
1784                         inode->i_op = &proc_tgid_attr_inode_operations;
1785                         inode->i_fop = &proc_tgid_attr_operations;
1786                         break;
1787                 case PROC_TID_ATTR_CURRENT:
1788                 case PROC_TGID_ATTR_CURRENT:
1789                 case PROC_TID_ATTR_PREV:
1790                 case PROC_TGID_ATTR_PREV:
1791                 case PROC_TID_ATTR_EXEC:
1792                 case PROC_TGID_ATTR_EXEC:
1793                 case PROC_TID_ATTR_FSCREATE:
1794                 case PROC_TGID_ATTR_FSCREATE:
1795                 case PROC_TID_ATTR_KEYCREATE:
1796                 case PROC_TGID_ATTR_KEYCREATE:
1797                 case PROC_TID_ATTR_SOCKCREATE:
1798                 case PROC_TGID_ATTR_SOCKCREATE:
1799                         inode->i_fop = &proc_pid_attr_operations;
1800                         break;
1801 #endif
1802 #ifdef CONFIG_KALLSYMS
1803                 case PROC_TID_WCHAN:
1804                 case PROC_TGID_WCHAN:
1805                         inode->i_fop = &proc_info_file_operations;
1806                         ei->op.proc_read = proc_pid_wchan;
1807                         break;
1808 #endif
1809 #ifdef CONFIG_SCHEDSTATS
1810                 case PROC_TID_SCHEDSTAT:
1811                 case PROC_TGID_SCHEDSTAT:
1812                         inode->i_fop = &proc_info_file_operations;
1813                         ei->op.proc_read = proc_pid_schedstat;
1814                         break;
1815 #endif
1816 #ifdef CONFIG_CPUSETS
1817                 case PROC_TID_CPUSET:
1818                 case PROC_TGID_CPUSET:
1819                         inode->i_fop = &proc_cpuset_operations;
1820                         break;
1821 #endif
1822                 case PROC_TID_OOM_SCORE:
1823                 case PROC_TGID_OOM_SCORE:
1824                         inode->i_fop = &proc_info_file_operations;
1825                         ei->op.proc_read = proc_oom_score;
1826                         break;
1827                 case PROC_TID_OOM_ADJUST:
1828                 case PROC_TGID_OOM_ADJUST:
1829                         inode->i_fop = &proc_oom_adjust_operations;
1830                         break;
1831 #ifdef CONFIG_AUDITSYSCALL
1832                 case PROC_TID_LOGINUID:
1833                 case PROC_TGID_LOGINUID:
1834                         inode->i_fop = &proc_loginuid_operations;
1835                         break;
1836 #endif
1837                 default:
1838                         printk("procfs: impossible type (%d)",p->type);
1839                         iput(inode);
1840                         error = ERR_PTR(-EINVAL);
1841                         goto out;
1842         }
1843         dentry->d_op = &pid_dentry_operations;
1844         d_add(dentry, inode);
1845         /* Close the race of the process dying before we return the dentry */
1846         if (pid_revalidate(dentry, NULL))
1847                 error = NULL;
1848 out:
1849         put_task_struct(task);
1850 out_no_task:
1851         return error;
1852 }
1853
1854 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1855         return proc_pident_lookup(dir, dentry, tgid_base_stuff);
1856 }
1857
1858 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1859         return proc_pident_lookup(dir, dentry, tid_base_stuff);
1860 }
1861
1862 static struct file_operations proc_tgid_base_operations = {
1863         .read           = generic_read_dir,
1864         .readdir        = proc_tgid_base_readdir,
1865 };
1866
1867 static struct file_operations proc_tid_base_operations = {
1868         .read           = generic_read_dir,
1869         .readdir        = proc_tid_base_readdir,
1870 };
1871
1872 static struct inode_operations proc_tgid_base_inode_operations = {
1873         .lookup         = proc_tgid_base_lookup,
1874         .getattr        = pid_getattr,
1875         .setattr        = proc_setattr,
1876 };
1877
1878 static struct inode_operations proc_tid_base_inode_operations = {
1879         .lookup         = proc_tid_base_lookup,
1880         .getattr        = pid_getattr,
1881         .setattr        = proc_setattr,
1882 };
1883
1884 #ifdef CONFIG_SECURITY
1885 static int proc_tgid_attr_readdir(struct file * filp,
1886                              void * dirent, filldir_t filldir)
1887 {
1888         return proc_pident_readdir(filp,dirent,filldir,
1889                                    tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
1890 }
1891
1892 static int proc_tid_attr_readdir(struct file * filp,
1893                              void * dirent, filldir_t filldir)
1894 {
1895         return proc_pident_readdir(filp,dirent,filldir,
1896                                    tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
1897 }
1898
1899 static struct file_operations proc_tgid_attr_operations = {
1900         .read           = generic_read_dir,
1901         .readdir        = proc_tgid_attr_readdir,
1902 };
1903
1904 static struct file_operations proc_tid_attr_operations = {
1905         .read           = generic_read_dir,
1906         .readdir        = proc_tid_attr_readdir,
1907 };
1908
1909 static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
1910                                 struct dentry *dentry, struct nameidata *nd)
1911 {
1912         return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
1913 }
1914
1915 static struct dentry *proc_tid_attr_lookup(struct inode *dir,
1916                                 struct dentry *dentry, struct nameidata *nd)
1917 {
1918         return proc_pident_lookup(dir, dentry, tid_attr_stuff);
1919 }
1920
1921 static struct inode_operations proc_tgid_attr_inode_operations = {
1922         .lookup         = proc_tgid_attr_lookup,
1923         .getattr        = pid_getattr,
1924         .setattr        = proc_setattr,
1925 };
1926
1927 static struct inode_operations proc_tid_attr_inode_operations = {
1928         .lookup         = proc_tid_attr_lookup,
1929         .getattr        = pid_getattr,
1930         .setattr        = proc_setattr,
1931 };
1932 #endif
1933
1934 /*
1935  * /proc/self:
1936  */
1937 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
1938                               int buflen)
1939 {
1940         char tmp[PROC_NUMBUF];
1941         sprintf(tmp, "%d", current->tgid);
1942         return vfs_readlink(dentry,buffer,buflen,tmp);
1943 }
1944
1945 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
1946 {
1947         char tmp[PROC_NUMBUF];
1948         sprintf(tmp, "%d", current->tgid);
1949         return ERR_PTR(vfs_follow_link(nd,tmp));
1950 }
1951
1952 static struct inode_operations proc_self_inode_operations = {
1953         .readlink       = proc_self_readlink,
1954         .follow_link    = proc_self_follow_link,
1955 };
1956
1957 /**
1958  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
1959  *
1960  * @task: task that should be flushed.
1961  *
1962  * Looks in the dcache for
1963  * /proc/@pid
1964  * /proc/@tgid/task/@pid
1965  * if either directory is present flushes it and all of it'ts children
1966  * from the dcache.
1967  *
1968  * It is safe and reasonable to cache /proc entries for a task until
1969  * that task exits.  After that they just clog up the dcache with
1970  * useless entries, possibly causing useful dcache entries to be
1971  * flushed instead.  This routine is proved to flush those useless
1972  * dcache entries at process exit time.
1973  *
1974  * NOTE: This routine is just an optimization so it does not guarantee
1975  *       that no dcache entries will exist at process exit time it
1976  *       just makes it very unlikely that any will persist.
1977  */
1978 void proc_flush_task(struct task_struct *task)
1979 {
1980         struct dentry *dentry, *leader, *dir;
1981         char buf[PROC_NUMBUF];
1982         struct qstr name;
1983
1984         name.name = buf;
1985         name.len = snprintf(buf, sizeof(buf), "%d", task->pid);
1986         dentry = d_hash_and_lookup(proc_mnt->mnt_root, &name);
1987         if (dentry) {
1988                 shrink_dcache_parent(dentry);
1989                 d_drop(dentry);
1990                 dput(dentry);
1991         }
1992
1993         if (thread_group_leader(task))
1994                 goto out;
1995
1996         name.name = buf;
1997         name.len = snprintf(buf, sizeof(buf), "%d", task->tgid);
1998         leader = d_hash_and_lookup(proc_mnt->mnt_root, &name);
1999         if (!leader)
2000                 goto out;
2001
2002         name.name = "task";
2003         name.len = strlen(name.name);
2004         dir = d_hash_and_lookup(leader, &name);
2005         if (!dir)
2006                 goto out_put_leader;
2007
2008         name.name = buf;
2009         name.len = snprintf(buf, sizeof(buf), "%d", task->pid);
2010         dentry = d_hash_and_lookup(dir, &name);
2011         if (dentry) {
2012                 shrink_dcache_parent(dentry);
2013                 d_drop(dentry);
2014                 dput(dentry);
2015         }
2016
2017         dput(dir);
2018 out_put_leader:
2019         dput(leader);
2020 out:
2021         return;
2022 }
2023
2024 /* SMP-safe */
2025 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2026 {
2027         struct dentry *result = ERR_PTR(-ENOENT);
2028         struct task_struct *task;
2029         struct inode *inode;
2030         struct proc_inode *ei;
2031         unsigned tgid;
2032
2033         if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
2034                 inode = new_inode(dir->i_sb);
2035                 if (!inode)
2036                         return ERR_PTR(-ENOMEM);
2037                 ei = PROC_I(inode);
2038                 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2039                 inode->i_ino = fake_ino(0, PROC_TGID_INO);
2040                 ei->pde = NULL;
2041                 inode->i_mode = S_IFLNK|S_IRWXUGO;
2042                 inode->i_uid = inode->i_gid = 0;
2043                 inode->i_size = 64;
2044                 inode->i_op = &proc_self_inode_operations;
2045                 d_add(dentry, inode);
2046                 return NULL;
2047         }
2048         tgid = name_to_int(dentry);
2049         if (tgid == ~0U)
2050                 goto out;
2051
2052         rcu_read_lock();
2053         task = find_task_by_pid(tgid);
2054         if (task)
2055                 get_task_struct(task);
2056         rcu_read_unlock();
2057         if (!task)
2058                 goto out;
2059
2060         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
2061         if (!inode)
2062                 goto out_put_task;
2063
2064         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2065         inode->i_op = &proc_tgid_base_inode_operations;
2066         inode->i_fop = &proc_tgid_base_operations;
2067         inode->i_flags|=S_IMMUTABLE;
2068 #ifdef CONFIG_SECURITY
2069         inode->i_nlink = 5;
2070 #else
2071         inode->i_nlink = 4;
2072 #endif
2073
2074         dentry->d_op = &pid_dentry_operations;
2075
2076         d_add(dentry, inode);
2077         /* Close the race of the process dying before we return the dentry */
2078         if (pid_revalidate(dentry, NULL))
2079                 result = NULL;
2080
2081 out_put_task:
2082         put_task_struct(task);
2083 out:
2084         return result;
2085 }
2086
2087 /* SMP-safe */
2088 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2089 {
2090         struct dentry *result = ERR_PTR(-ENOENT);
2091         struct task_struct *task;
2092         struct task_struct *leader = get_proc_task(dir);
2093         struct inode *inode;
2094         unsigned tid;
2095
2096         if (!leader)
2097                 goto out_no_task;
2098
2099         tid = name_to_int(dentry);
2100         if (tid == ~0U)
2101                 goto out;
2102
2103         rcu_read_lock();
2104         task = find_task_by_pid(tid);
2105         if (task)
2106                 get_task_struct(task);
2107         rcu_read_unlock();
2108         if (!task)
2109                 goto out;
2110         if (leader->tgid != task->tgid)
2111                 goto out_drop_task;
2112
2113         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);
2114
2115
2116         if (!inode)
2117                 goto out_drop_task;
2118         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2119         inode->i_op = &proc_tid_base_inode_operations;
2120         inode->i_fop = &proc_tid_base_operations;
2121         inode->i_flags|=S_IMMUTABLE;
2122 #ifdef CONFIG_SECURITY
2123         inode->i_nlink = 4;
2124 #else
2125         inode->i_nlink = 3;
2126 #endif
2127
2128         dentry->d_op = &pid_dentry_operations;
2129
2130         d_add(dentry, inode);
2131         /* Close the race of the process dying before we return the dentry */
2132         if (pid_revalidate(dentry, NULL))
2133                 result = NULL;
2134
2135 out_drop_task:
2136         put_task_struct(task);
2137 out:
2138         put_task_struct(leader);
2139 out_no_task:
2140         return result;
2141 }
2142
2143 /*
2144  * Find the first tgid to return to user space.
2145  *
2146  * Usually this is just whatever follows &init_task, but if the users
2147  * buffer was too small to hold the full list or there was a seek into
2148  * the middle of the directory we have more work to do.
2149  *
2150  * In the case of a short read we start with find_task_by_pid.
2151  *
2152  * In the case of a seek we start with &init_task and walk nr
2153  * threads past it.
2154  */
2155 static struct task_struct *first_tgid(int tgid, unsigned int nr)
2156 {
2157         struct task_struct *pos;
2158         rcu_read_lock();
2159         if (tgid && nr) {
2160                 pos = find_task_by_pid(tgid);
2161                 if (pos && thread_group_leader(pos))
2162                         goto found;
2163         }
2164         /* If nr exceeds the number of processes get out quickly */
2165         pos = NULL;
2166         if (nr && nr >= nr_processes())
2167                 goto done;
2168
2169         /* If we haven't found our starting place yet start with
2170          * the init_task and walk nr tasks forward.
2171          */
2172         for (pos = next_task(&init_task); nr > 0; --nr) {
2173                 pos = next_task(pos);
2174                 if (pos == &init_task) {
2175                         pos = NULL;
2176                         goto done;
2177                 }
2178         }
2179 found:
2180         get_task_struct(pos);
2181 done:
2182         rcu_read_unlock();
2183         return pos;
2184 }
2185
2186 /*
2187  * Find the next task in the task list.
2188  * Return NULL if we loop or there is any error.
2189  *
2190  * The reference to the input task_struct is released.
2191  */
2192 static struct task_struct *next_tgid(struct task_struct *start)
2193 {
2194         struct task_struct *pos;
2195         rcu_read_lock();
2196         pos = start;
2197         if (pid_alive(start))
2198                 pos = next_task(start);
2199         if (pid_alive(pos) && (pos != &init_task)) {
2200                 get_task_struct(pos);
2201                 goto done;
2202         }
2203         pos = NULL;
2204 done:
2205         rcu_read_unlock();
2206         put_task_struct(start);
2207         return pos;
2208 }
2209
2210 /* for the /proc/ directory itself, after non-process stuff has been done */
2211 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2212 {
2213         char buf[PROC_NUMBUF];
2214         unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2215         struct task_struct *task;
2216         int tgid;
2217
2218         if (!nr) {
2219                 ino_t ino = fake_ino(0,PROC_TGID_INO);
2220                 if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
2221                         return 0;
2222                 filp->f_pos++;
2223                 nr++;
2224         }
2225         nr -= 1;
2226
2227         /* f_version caches the tgid value that the last readdir call couldn't
2228          * return. lseek aka telldir automagically resets f_version to 0.
2229          */
2230         tgid = filp->f_version;
2231         filp->f_version = 0;
2232         for (task = first_tgid(tgid, nr);
2233              task;
2234              task = next_tgid(task), filp->f_pos++) {
2235                 int len;
2236                 ino_t ino;
2237                 tgid = task->pid;
2238                 len = snprintf(buf, sizeof(buf), "%d", tgid);
2239                 ino = fake_ino(tgid, PROC_TGID_INO);
2240                 if (filldir(dirent, buf, len, filp->f_pos, ino, DT_DIR) < 0) {
2241                         /* returning this tgid failed, save it as the first
2242                          * pid for the next readir call */
2243                         filp->f_version = tgid;
2244                         put_task_struct(task);
2245                         break;
2246                 }
2247         }
2248         return 0;
2249 }
2250
2251 /*
2252  * Find the first tid of a thread group to return to user space.
2253  *
2254  * Usually this is just the thread group leader, but if the users
2255  * buffer was too small or there was a seek into the middle of the
2256  * directory we have more work todo.
2257  *
2258  * In the case of a short read we start with find_task_by_pid.
2259  *
2260  * In the case of a seek we start with the leader and walk nr
2261  * threads past it.
2262  */
2263 static struct task_struct *first_tid(struct task_struct *leader,
2264                                         int tid, int nr)
2265 {
2266         struct task_struct *pos;
2267
2268         rcu_read_lock();
2269         /* Attempt to start with the pid of a thread */
2270         if (tid && (nr > 0)) {
2271                 pos = find_task_by_pid(tid);
2272                 if (pos && (pos->group_leader == leader))
2273                         goto found;
2274         }
2275
2276         /* If nr exceeds the number of threads there is nothing todo */
2277         pos = NULL;
2278         if (nr && nr >= get_nr_threads(leader))
2279                 goto out;
2280
2281         /* If we haven't found our starting place yet start
2282          * with the leader and walk nr threads forward.
2283          */
2284         for (pos = leader; nr > 0; --nr) {
2285                 pos = next_thread(pos);
2286                 if (pos == leader) {
2287                         pos = NULL;
2288                         goto out;
2289                 }
2290         }
2291 found:
2292         get_task_struct(pos);
2293 out:
2294         rcu_read_unlock();
2295         return pos;
2296 }
2297
2298 /*
2299  * Find the next thread in the thread list.
2300  * Return NULL if there is an error or no next thread.
2301  *
2302  * The reference to the input task_struct is released.
2303  */
2304 static struct task_struct *next_tid(struct task_struct *start)
2305 {
2306         struct task_struct *pos = NULL;
2307         rcu_read_lock();
2308         if (pid_alive(start)) {
2309                 pos = next_thread(start);
2310                 if (thread_group_leader(pos))
2311                         pos = NULL;
2312                 else
2313                         get_task_struct(pos);
2314         }
2315         rcu_read_unlock();
2316         put_task_struct(start);
2317         return pos;
2318 }
2319
2320 /* for the /proc/TGID/task/ directories */
2321 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
2322 {
2323         char buf[PROC_NUMBUF];
2324         struct dentry *dentry = filp->f_dentry;
2325         struct inode *inode = dentry->d_inode;
2326         struct task_struct *leader = get_proc_task(inode);
2327         struct task_struct *task;
2328         int retval = -ENOENT;
2329         ino_t ino;
2330         int tid;
2331         unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
2332
2333         if (!leader)
2334                 goto out_no_task;
2335         retval = 0;
2336
2337         switch (pos) {
2338         case 0:
2339                 ino = inode->i_ino;
2340                 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
2341                         goto out;
2342                 pos++;
2343                 /* fall through */
2344         case 1:
2345                 ino = parent_ino(dentry);
2346                 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
2347                         goto out;
2348                 pos++;
2349                 /* fall through */
2350         }
2351
2352         /* f_version caches the tgid value that the last readdir call couldn't
2353          * return. lseek aka telldir automagically resets f_version to 0.
2354          */
2355         tid = filp->f_version;
2356         filp->f_version = 0;
2357         for (task = first_tid(leader, tid, pos - 2);
2358              task;
2359              task = next_tid(task), pos++) {
2360                 int len;
2361                 tid = task->pid;
2362                 len = snprintf(buf, sizeof(buf), "%d", tid);
2363                 ino = fake_ino(tid, PROC_TID_INO);
2364                 if (filldir(dirent, buf, len, pos, ino, DT_DIR < 0)) {
2365                         /* returning this tgid failed, save it as the first
2366                          * pid for the next readir call */
2367                         filp->f_version = tid;
2368                         put_task_struct(task);
2369                         break;
2370                 }
2371         }
2372 out:
2373         filp->f_pos = pos;
2374         put_task_struct(leader);
2375 out_no_task:
2376         return retval;
2377 }
2378
2379 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
2380 {
2381         struct inode *inode = dentry->d_inode;
2382         struct task_struct *p = get_proc_task(inode);
2383         generic_fillattr(inode, stat);
2384
2385         if (p) {
2386                 rcu_read_lock();
2387                 stat->nlink += get_nr_threads(p);
2388                 rcu_read_unlock();
2389                 put_task_struct(p);
2390         }
2391
2392         return 0;
2393 }