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 #include <asm/uaccess.h>
  17
  18 #include <linux/config.h>
  19 #include <linux/errno.h>
  20 #include <linux/time.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/stat.h>
  23 #include <linux/init.h>
  24 #include <linux/file.h>
  25 #include <linux/string.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/namei.h>
  28 #include <linux/namespace.h>
  29 #include <linux/mm.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/kallsyms.h>
  32 #include <linux/mount.h>
  33 #include <linux/security.h>
  34 #include <linux/ptrace.h>
  35 #include <linux/seccomp.h>
  36 #include <linux/cpuset.h>
  37 #include <linux/audit.h>
  38 #include "internal.h"
  39
  40 /*
  41  * For hysterical raisins we keep the same inumbers as in the old procfs.
  42  * Feel free to change the macro below - just keep the range distinct from
  43  * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
  44  * As soon as we'll get a separate superblock we will be able to forget
  45  * about magical ranges too.
  46  */
  47
  48 #define fake_ino(pid,ino) (((pid)<<16)|(ino))
  49
  50 enum pid_directory_inos {
  51         PROC_TGID_INO = 2,
  52         PROC_TGID_TASK,
  53         PROC_TGID_STATUS,
  54         PROC_TGID_MEM,
  55 #ifdef CONFIG_SECCOMP
  56         PROC_TGID_SECCOMP,
  57 #endif
  58         PROC_TGID_CWD,
  59         PROC_TGID_ROOT,
  60         PROC_TGID_EXE,
  61         PROC_TGID_FD,
  62         PROC_TGID_ENVIRON,
  63         PROC_TGID_AUXV,
  64         PROC_TGID_CMDLINE,
  65         PROC_TGID_STAT,
  66         PROC_TGID_STATM,
  67         PROC_TGID_MAPS,
  68         PROC_TGID_MOUNTS,
  69         PROC_TGID_WCHAN,
  70 #ifdef CONFIG_SCHEDSTATS
  71         PROC_TGID_SCHEDSTAT,
  72 #endif
  73 #ifdef CONFIG_CPUSETS
  74         PROC_TGID_CPUSET,
  75 #endif
  76 #ifdef CONFIG_SECURITY
  77         PROC_TGID_ATTR,
  78         PROC_TGID_ATTR_CURRENT,
  79         PROC_TGID_ATTR_PREV,
  80         PROC_TGID_ATTR_EXEC,
  81         PROC_TGID_ATTR_FSCREATE,
  82 #endif
  83 #ifdef CONFIG_AUDITSYSCALL
  84         PROC_TGID_LOGINUID,
  85 #endif
  86         PROC_TGID_FD_DIR,
  87         PROC_TGID_OOM_SCORE,
  88         PROC_TGID_OOM_ADJUST,
  89         PROC_TID_INO,
  90         PROC_TID_STATUS,
  91         PROC_TID_MEM,
  92 #ifdef CONFIG_SECCOMP
  93         PROC_TID_SECCOMP,
  94 #endif
  95         PROC_TID_CWD,
  96         PROC_TID_ROOT,
  97         PROC_TID_EXE,
  98         PROC_TID_FD,
  99         PROC_TID_ENVIRON,
 100         PROC_TID_AUXV,
 101         PROC_TID_CMDLINE,
 102         PROC_TID_STAT,
 103         PROC_TID_STATM,
 104         PROC_TID_MAPS,
 105         PROC_TID_MOUNTS,
 106         PROC_TID_WCHAN,
 107 #ifdef CONFIG_SCHEDSTATS
 108         PROC_TID_SCHEDSTAT,
 109 #endif
 110 #ifdef CONFIG_CPUSETS
 111         PROC_TID_CPUSET,
 112 #endif
 113 #ifdef CONFIG_SECURITY
 114         PROC_TID_ATTR,
 115         PROC_TID_ATTR_CURRENT,
 116         PROC_TID_ATTR_PREV,
 117         PROC_TID_ATTR_EXEC,
 118         PROC_TID_ATTR_FSCREATE,
 119 #endif
 120 #ifdef CONFIG_AUDITSYSCALL
 121         PROC_TID_LOGINUID,
 122 #endif
 123         PROC_TID_FD_DIR = 0x8000,       /* 0x8000-0xffff */
 124         PROC_TID_OOM_SCORE,
 125         PROC_TID_OOM_ADJUST,
 126 };
 127
 128 struct pid_entry {
 129         int type;
 130         int len;
 131         char *name;
 132         mode_t mode;
 133 };
 134
 135 #define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}
 136
 137 static struct pid_entry tgid_base_stuff[] = {
 138         E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
 139         E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
 140         E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
 141         E(PROC_TGID_AUXV,      "auxv",    S_IFREG|S_IRUSR),
 142         E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
 143         E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
 144         E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
 145         E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
 146         E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
 147         E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 148 #ifdef CONFIG_SECCOMP
 149         E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
 150 #endif
 151         E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
 152         E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
 153         E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
 154         E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
 155 #ifdef CONFIG_SECURITY
 156         E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
 157 #endif
 158 #ifdef CONFIG_KALLSYMS
 159         E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
 160 #endif
 161 #ifdef CONFIG_SCHEDSTATS
 162         E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
 163 #endif
 164 #ifdef CONFIG_CPUSETS
 165         E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
 166 #endif
 167         E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
 168         E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
 169 #ifdef CONFIG_AUDITSYSCALL
 170         E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 171 #endif
 172         {0,0,NULL,0}
 173 };
 174 static struct pid_entry tid_base_stuff[] = {
 175         E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
 176         E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
 177         E(PROC_TID_AUXV,       "auxv",    S_IFREG|S_IRUSR),
 178         E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
 179         E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
 180         E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
 181         E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
 182         E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
 183         E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 184 #ifdef CONFIG_SECCOMP
 185         E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
 186 #endif
 187         E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
 188         E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
 189         E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
 190         E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
 191 #ifdef CONFIG_SECURITY
 192         E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
 193 #endif
 194 #ifdef CONFIG_KALLSYMS
 195         E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
 196 #endif
 197 #ifdef CONFIG_SCHEDSTATS
 198         E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
 199 #endif
 200 #ifdef CONFIG_CPUSETS
 201         E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
 202 #endif
 203         E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
 204         E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
 205 #ifdef CONFIG_AUDITSYSCALL
 206         E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
 207 #endif
 208         {0,0,NULL,0}
 209 };
 210
 211 #ifdef CONFIG_SECURITY
 212 static struct pid_entry tgid_attr_stuff[] = {
 213         E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
 214         E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
 215         E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
 216         E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 217         {0,0,NULL,0}
 218 };
 219 static struct pid_entry tid_attr_stuff[] = {
 220         E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
 221         E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
 222         E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
 223         E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 224         {0,0,NULL,0}
 225 };
 226 #endif
 227
 228 #undef E
 229
 230 static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 231 {
 232         struct task_struct *task = proc_task(inode);
 233         struct files_struct *files;
 234         struct file *file;
 235         int fd = proc_type(inode) - PROC_TID_FD_DIR;
 236
 237         files = get_files_struct(task);
 238         if (files) {
 239                 spin_lock(&files->file_lock);
 240                 file = fcheck_files(files, fd);
 241                 if (file) {
 242                         *mnt = mntget(file->f_vfsmnt);
 243                         *dentry = dget(file->f_dentry);
 244                         spin_unlock(&files->file_lock);
 245                         put_files_struct(files);
 246                         return 0;
 247                 }
 248                 spin_unlock(&files->file_lock);
 249                 put_files_struct(files);
 250         }
 251         return -ENOENT;
 252 }
 253
 254 static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 255 {
 256         struct fs_struct *fs;
 257         int result = -ENOENT;
 258         task_lock(proc_task(inode));
 259         fs = proc_task(inode)->fs;
 260         if(fs)
 261                 atomic_inc(&fs->count);
 262         task_unlock(proc_task(inode));
 263         if (fs) {
 264                 read_lock(&fs->lock);
 265                 *mnt = mntget(fs->pwdmnt);
 266                 *dentry = dget(fs->pwd);
 267                 read_unlock(&fs->lock);
 268                 result = 0;
 269                 put_fs_struct(fs);
 270         }
 271         return result;
 272 }
 273
 274 static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
 275 {
 276         struct fs_struct *fs;
 277         int result = -ENOENT;
 278         task_lock(proc_task(inode));
 279         fs = proc_task(inode)->fs;
 280         if(fs)
 281                 atomic_inc(&fs->count);
 282         task_unlock(proc_task(inode));
 283         if (fs) {
 284                 read_lock(&fs->lock);
 285                 *mnt = mntget(fs->rootmnt);
 286                 *dentry = dget(fs->root);
 287                 read_unlock(&fs->lock);
 288                 result = 0;
 289                 put_fs_struct(fs);
 290         }
 291         return result;
 292 }
 293
 294 #define MAY_PTRACE(task) \
 295         (task == current || \
 296         (task->parent == current && \
 297         (task->ptrace & PT_PTRACED) && \
 298          (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
 299          security_ptrace(current,task) == 0))
 300
 301 static int may_ptrace_attach(struct task_struct *task)
 302 {
 303         int retval = 0;
 304
 305         task_lock(task);
 306
 307         if (!task->mm)
 308                 goto out;
 309         if (((current->uid != task->euid) ||
 310              (current->uid != task->suid) ||
 311              (current->uid != task->uid) ||
 312              (current->gid != task->egid) ||
 313              (current->gid != task->sgid) ||
 314              (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
 315                 goto out;
 316         rmb();
 317         if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
 318                 goto out;
 319         if (security_ptrace(current, task))
 320                 goto out;
 321
 322         retval = 1;
 323 out:
 324         task_unlock(task);
 325         return retval;
 326 }
 327
 328 static int proc_pid_environ(struct task_struct *task, char * buffer)
 329 {
 330         int res = 0;
 331         struct mm_struct *mm = get_task_mm(task);
 332         if (mm) {
 333                 unsigned int len = mm->env_end - mm->env_start;
 334                 if (len > PAGE_SIZE)
 335                         len = PAGE_SIZE;
 336                 res = access_process_vm(task, mm->env_start, buffer, len, 0);
 337                 if (!may_ptrace_attach(task))
 338                         res = -ESRCH;
 339                 mmput(mm);
 340         }
 341         return res;
 342 }
 343
 344 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 345 {
 346         int res = 0;
 347         unsigned int len;
 348         struct mm_struct *mm = get_task_mm(task);
 349         if (!mm)
 350                 goto out;
 351         if (!mm->arg_end)
 352                 goto out_mm;    /* Shh! No looking before we're done */
 353
 354         len = mm->arg_end - mm->arg_start;
 355
 356         if (len > PAGE_SIZE)
 357                 len = PAGE_SIZE;
 358
 359         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 360
 361         // If the nul at the end of args has been overwritten, then
 362         // assume application is using setproctitle(3).
 363         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 364                 len = strnlen(buffer, res);
 365                 if (len < res) {
 366                     res = len;
 367                 } else {
 368                         len = mm->env_end - mm->env_start;
 369                         if (len > PAGE_SIZE - res)
 370                                 len = PAGE_SIZE - res;
 371                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 372                         res = strnlen(buffer, res);
 373                 }
 374         }
 375 out_mm:
 376         mmput(mm);
 377 out:
 378         return res;
 379 }
 380
 381 static int proc_pid_auxv(struct task_struct *task, char *buffer)
 382 {
 383         int res = 0;
 384         struct mm_struct *mm = get_task_mm(task);
 385         if (mm) {
 386                 unsigned int nwords = 0;
 387                 do
 388                         nwords += 2;
 389                 while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 390                 res = nwords * sizeof(mm->saved_auxv[0]);
 391                 if (res > PAGE_SIZE)
 392                         res = PAGE_SIZE;
 393                 memcpy(buffer, mm->saved_auxv, res);
 394                 mmput(mm);
 395         }
 396         return res;
 397 }
 398
 399
 400 #ifdef CONFIG_KALLSYMS
 401 /*
 402  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 403  * Returns the resolved symbol.  If that fails, simply return the address.
 404  */
 405 static int proc_pid_wchan(struct task_struct *task, char *buffer)
 406 {
 407         char *modname;
 408         const char *sym_name;
 409         unsigned long wchan, size, offset;
 410         char namebuf[KSYM_NAME_LEN+1];
 411
 412         wchan = get_wchan(task);
 413
 414         sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
 415         if (sym_name)
 416                 return sprintf(buffer, "%s", sym_name);
 417         return sprintf(buffer, "%lu", wchan);
 418 }
 419 #endif /* CONFIG_KALLSYMS */
 420
 421 #ifdef CONFIG_SCHEDSTATS
 422 /*
 423  * Provides /proc/PID/schedstat
 424  */
 425 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 426 {
 427         return sprintf(buffer, "%lu %lu %lu\n",
 428                         task->sched_info.cpu_time,
 429                         task->sched_info.run_delay,
 430                         task->sched_info.pcnt);
 431 }
 432 #endif
 433
 434 /* The badness from the OOM killer */
 435 unsigned long badness(struct task_struct *p, unsigned long uptime);
 436 static int proc_oom_score(struct task_struct *task, char *buffer)
 437 {
 438         unsigned long points;
 439         struct timespec uptime;
 440
 441         do_posix_clock_monotonic_gettime(&uptime);
 442         points = badness(task, uptime.tv_sec);
 443         return sprintf(buffer, "%lu\n", points);
 444 }
 445
 446 /************************************************************************/
 447 /*                       Here the fs part begins                        */
 448 /************************************************************************/
 449
 450 /* permission checks */
 451
 452 static int proc_check_root(struct inode *inode)
 453 {
 454         struct dentry *de, *base, *root;
 455         struct vfsmount *our_vfsmnt, *vfsmnt, *mnt;
 456         int res = 0;
 457
 458         if (proc_root_link(inode, &root, &vfsmnt)) /* Ewww... */
 459                 return -ENOENT;
 460         read_lock(&current->fs->lock);
 461         our_vfsmnt = mntget(current->fs->rootmnt);
 462         base = dget(current->fs->root);
 463         read_unlock(&current->fs->lock);
 464
 465         spin_lock(&vfsmount_lock);
 466         de = root;
 467         mnt = vfsmnt;
 468
 469         while (vfsmnt != our_vfsmnt) {
 470                 if (vfsmnt == vfsmnt->mnt_parent)
 471                         goto out;
 472                 de = vfsmnt->mnt_mountpoint;
 473                 vfsmnt = vfsmnt->mnt_parent;
 474         }
 475
 476         if (!is_subdir(de, base))
 477                 goto out;
 478         spin_unlock(&vfsmount_lock);
 479
 480 exit:
 481         dput(base);
 482         mntput(our_vfsmnt);
 483         dput(root);
 484         mntput(mnt);
 485         return res;
 486 out:
 487         spin_unlock(&vfsmount_lock);
 488         res = -EACCES;
 489         goto exit;
 490 }
 491
 492 static int proc_permission(struct inode *inode, int mask, struct nameidata *nd)
 493 {
 494         if (generic_permission(inode, mask, NULL) != 0)
 495                 return -EACCES;
 496         return proc_check_root(inode);
 497 }
 498
 499 extern struct seq_operations proc_pid_maps_op;
 500 static int maps_open(struct inode *inode, struct file *file)
 501 {
 502         struct task_struct *task = proc_task(inode);
 503         int ret = seq_open(file, &proc_pid_maps_op);
 504         if (!ret) {
 505                 struct seq_file *m = file->private_data;
 506                 m->private = task;
 507         }
 508         return ret;
 509 }
 510
 511 static struct file_operations proc_maps_operations = {
 512         .open           = maps_open,
 513         .read           = seq_read,
 514         .llseek         = seq_lseek,
 515         .release        = seq_release,
 516 };
 517
 518 extern struct seq_operations mounts_op;
 519 static int mounts_open(struct inode *inode, struct file *file)
 520 {
 521         struct task_struct *task = proc_task(inode);
 522         int ret = seq_open(file, &mounts_op);
 523
 524         if (!ret) {
 525                 struct seq_file *m = file->private_data;
 526                 struct namespace *namespace;
 527                 task_lock(task);
 528                 namespace = task->namespace;
 529                 if (namespace)
 530                         get_namespace(namespace);
 531                 task_unlock(task);
 532
 533                 if (namespace)
 534                         m->private = namespace;
 535                 else {
 536                         seq_release(inode, file);
 537                         ret = -EINVAL;
 538                 }
 539         }
 540         return ret;
 541 }
 542
 543 static int mounts_release(struct inode *inode, struct file *file)
 544 {
 545         struct seq_file *m = file->private_data;
 546         struct namespace *namespace = m->private;
 547         put_namespace(namespace);
 548         return seq_release(inode, file);
 549 }
 550
 551 static struct file_operations proc_mounts_operations = {
 552         .open           = mounts_open,
 553         .read           = seq_read,
 554         .llseek         = seq_lseek,
 555         .release        = mounts_release,
 556 };
 557
 558 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 559
 560 static ssize_t proc_info_read(struct file * file, char __user * buf,
 561                           size_t count, loff_t *ppos)
 562 {
 563         struct inode * inode = file->f_dentry->d_inode;
 564         unsigned long page;
 565         ssize_t length;
 566         struct task_struct *task = proc_task(inode);
 567
 568         if (count > PROC_BLOCK_SIZE)
 569                 count = PROC_BLOCK_SIZE;
 570         if (!(page = __get_free_page(GFP_KERNEL)))
 571                 return -ENOMEM;
 572
 573         length = PROC_I(inode)->op.proc_read(task, (char*)page);
 574
 575         if (length >= 0)
 576                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 577         free_page(page);
 578         return length;
 579 }
 580
 581 static struct file_operations proc_info_file_operations = {
 582         .read           = proc_info_read,
 583 };
 584
 585 static int mem_open(struct inode* inode, struct file* file)
 586 {
 587         file->private_data = (void*)((long)current->self_exec_id);
 588         return 0;
 589 }
 590
 591 static ssize_t mem_read(struct file * file, char __user * buf,
 592                         size_t count, loff_t *ppos)
 593 {
 594         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 595         char *page;
 596         unsigned long src = *ppos;
 597         int ret = -ESRCH;
 598         struct mm_struct *mm;
 599
 600         if (!MAY_PTRACE(task) || !may_ptrace_attach(task))
 601                 goto out;
 602
 603         ret = -ENOMEM;
 604         page = (char *)__get_free_page(GFP_USER);
 605         if (!page)
 606                 goto out;
 607
 608         ret = 0;
 609
 610         mm = get_task_mm(task);
 611         if (!mm)
 612                 goto out_free;
 613
 614         ret = -EIO;
 615
 616         if (file->private_data != (void*)((long)current->self_exec_id))
 617                 goto out_put;
 618
 619         ret = 0;
 620
 621         while (count > 0) {
 622                 int this_len, retval;
 623
 624                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 625                 retval = access_process_vm(task, src, page, this_len, 0);
 626                 if (!retval || !MAY_PTRACE(task) || !may_ptrace_attach(task)) {
 627                         if (!ret)
 628                                 ret = -EIO;
 629                         break;
 630                 }
 631
 632                 if (copy_to_user(buf, page, retval)) {
 633                         ret = -EFAULT;
 634                         break;
 635                 }
 636
 637                 ret += retval;
 638                 src += retval;
 639                 buf += retval;
 640                 count -= retval;
 641         }
 642         *ppos = src;
 643
 644 out_put:
 645         mmput(mm);
 646 out_free:
 647         free_page((unsigned long) page);
 648 out:
 649         return ret;
 650 }
 651
 652 #define mem_write NULL
 653
 654 #ifndef mem_write
 655 /* This is a security hazard */
 656 static ssize_t mem_write(struct file * file, const char * buf,
 657                          size_t count, loff_t *ppos)
 658 {
 659         int copied = 0;
 660         char *page;
 661         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 662         unsigned long dst = *ppos;
 663
 664         if (!MAY_PTRACE(task) || !may_ptrace_attach(task))
 665                 return -ESRCH;
 666
 667         page = (char *)__get_free_page(GFP_USER);
 668         if (!page)
 669                 return -ENOMEM;
 670
 671         while (count > 0) {
 672                 int this_len, retval;
 673
 674                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 675                 if (copy_from_user(page, buf, this_len)) {
 676                         copied = -EFAULT;
 677                         break;
 678                 }
 679                 retval = access_process_vm(task, dst, page, this_len, 1);
 680                 if (!retval) {
 681                         if (!copied)
 682                                 copied = -EIO;
 683                         break;
 684                 }
 685                 copied += retval;
 686                 buf += retval;
 687                 dst += retval;
 688                 count -= retval;
 689         }
 690         *ppos = dst;
 691         free_page((unsigned long) page);
 692         return copied;
 693 }
 694 #endif
 695
 696 static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
 697 {
 698         switch (orig) {
 699         case 0:
 700                 file->f_pos = offset;
 701                 break;
 702         case 1:
 703                 file->f_pos += offset;
 704                 break;
 705         default:
 706                 return -EINVAL;
 707         }
 708         force_successful_syscall_return();
 709         return file->f_pos;
 710 }
 711
 712 static struct file_operations proc_mem_operations = {
 713         .llseek         = mem_lseek,
 714         .read           = mem_read,
 715         .write          = mem_write,
 716         .open           = mem_open,
 717 };
 718
 719 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
 720                                 size_t count, loff_t *ppos)
 721 {
 722         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 723         char buffer[8];
 724         size_t len;
 725         int oom_adjust = task->oomkilladj;
 726         loff_t __ppos = *ppos;
 727
 728         len = sprintf(buffer, "%i\n", oom_adjust);
 729         if (__ppos >= len)
 730                 return 0;
 731         if (count > len-__ppos)
 732                 count = len-__ppos;
 733         if (copy_to_user(buf, buffer + __ppos, count))
 734                 return -EFAULT;
 735         *ppos = __ppos + count;
 736         return count;
 737 }
 738
 739 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 740                                 size_t count, loff_t *ppos)
 741 {
 742         struct task_struct *task = proc_task(file->f_dentry->d_inode);
 743         char buffer[8], *end;
 744         int oom_adjust;
 745
 746         if (!capable(CAP_SYS_RESOURCE))
 747                 return -EPERM;
 748         memset(buffer, 0, 8);
 749         if (count > 6)
 750                 count = 6;
 751         if (copy_from_user(buffer, buf, count))
 752                 return -EFAULT;
 753         oom_adjust = simple_strtol(buffer, &end, 0);
 754         if (oom_adjust < -16 || oom_adjust > 15)
 755                 return -EINVAL;
 756         if (*end == '\n')
 757                 end++;
 758         task->oomkilladj = oom_adjust;
 759         if (end - buffer == 0)
 760                 return -EIO;
 761         return end - buffer;
 762 }
 763
 764 static struct file_operations proc_oom_adjust_operations = {
 765         .read           = oom_adjust_read,
 766         .write          = oom_adjust_write,
 767 };
 768
 769 static struct inode_operations proc_mem_inode_operations = {
 770         .permission     = proc_permission,
 771 };
 772
 773 #ifdef CONFIG_AUDITSYSCALL
 774 #define TMPBUFLEN 21
 775 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
 776                                   size_t count, loff_t *ppos)
 777 {
 778         struct inode * inode = file->f_dentry->d_inode;
 779         struct task_struct *task = proc_task(inode);
 780         ssize_t length;
 781         char tmpbuf[TMPBUFLEN];
 782
 783         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
 784                                 audit_get_loginuid(task->audit_context));
 785         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 786 }
 787
 788 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 789                                    size_t count, loff_t *ppos)
 790 {
 791         struct inode * inode = file->f_dentry->d_inode;
 792         char *page, *tmp;
 793         ssize_t length;
 794         struct task_struct *task = proc_task(inode);
 795         uid_t loginuid;
 796
 797         if (!capable(CAP_AUDIT_CONTROL))
 798                 return -EPERM;
 799
 800         if (current != task)
 801                 return -EPERM;
 802
 803         if (count > PAGE_SIZE)
 804                 count = PAGE_SIZE;
 805
 806         if (*ppos != 0) {
 807                 /* No partial writes. */
 808                 return -EINVAL;
 809         }
 810         page = (char*)__get_free_page(GFP_USER);
 811         if (!page)
 812                 return -ENOMEM;
 813         length = -EFAULT;
 814         if (copy_from_user(page, buf, count))
 815                 goto out_free_page;
 816
 817         loginuid = simple_strtoul(page, &tmp, 10);
 818         if (tmp == page) {
 819                 length = -EINVAL;
 820                 goto out_free_page;
 821
 822         }
 823         length = audit_set_loginuid(task->audit_context, loginuid);
 824         if (likely(length == 0))
 825                 length = count;
 826
 827 out_free_page:
 828         free_page((unsigned long) page);
 829         return length;
 830 }
 831
 832 static struct file_operations proc_loginuid_operations = {
 833         .read           = proc_loginuid_read,
 834         .write          = proc_loginuid_write,
 835 };
 836 #endif
 837
 838 #ifdef CONFIG_SECCOMP
 839 static ssize_t seccomp_read(struct file *file, char __user *buf,
 840                             size_t count, loff_t *ppos)
 841 {
 842         struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
 843         char __buf[20];
 844         loff_t __ppos = *ppos;
 845         size_t len;
 846
 847         /* no need to print the trailing zero, so use only len */
 848         len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
 849         if (__ppos >= len)
 850                 return 0;
 851         if (count > len - __ppos)
 852                 count = len - __ppos;
 853         if (copy_to_user(buf, __buf + __ppos, count))
 854                 return -EFAULT;
 855         *ppos = __ppos + count;
 856         return count;
 857 }
 858
 859 static ssize_t seccomp_write(struct file *file, const char __user *buf,
 860                              size_t count, loff_t *ppos)
 861 {
 862         struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
 863         char __buf[20], *end;
 864         unsigned int seccomp_mode;
 865
 866         /* can set it only once to be even more secure */
 867         if (unlikely(tsk->seccomp.mode))
 868                 return -EPERM;
 869
 870         memset(__buf, 0, sizeof(__buf));
 871         count = min(count, sizeof(__buf) - 1);
 872         if (copy_from_user(__buf, buf, count))
 873                 return -EFAULT;
 874         seccomp_mode = simple_strtoul(__buf, &end, 0);
 875         if (*end == '\n')
 876                 end++;
 877         if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
 878                 tsk->seccomp.mode = seccomp_mode;
 879                 set_tsk_thread_flag(tsk, TIF_SECCOMP);
 880         } else
 881                 return -EINVAL;
 882         if (unlikely(!(end - __buf)))
 883                 return -EIO;
 884         return end - __buf;
 885 }
 886
 887 static struct file_operations proc_seccomp_operations = {
 888         .read           = seccomp_read,
 889         .write          = seccomp_write,
 890 };
 891 #endif /* CONFIG_SECCOMP */
 892
 893 static int proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
 894 {
 895         struct inode *inode = dentry->d_inode;
 896         int error = -EACCES;
 897
 898         /* We don't need a base pointer in the /proc filesystem */
 899         path_release(nd);
 900
 901         if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
 902                 goto out;
 903         error = proc_check_root(inode);
 904         if (error)
 905                 goto out;
 906
 907         error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
 908         nd->last_type = LAST_BIND;
 909 out:
 910         return error;
 911 }
 912
 913 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
 914                             char __user *buffer, int buflen)
 915 {
 916         struct inode * inode;
 917         char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
 918         int len;
 919
 920         if (!tmp)
 921                 return -ENOMEM;
 922
 923         inode = dentry->d_inode;
 924         path = d_path(dentry, mnt, tmp, PAGE_SIZE);
 925         len = PTR_ERR(path);
 926         if (IS_ERR(path))
 927                 goto out;
 928         len = tmp + PAGE_SIZE - 1 - path;
 929
 930         if (len > buflen)
 931                 len = buflen;
 932         if (copy_to_user(buffer, path, len))
 933                 len = -EFAULT;
 934  out:
 935         free_page((unsigned long)tmp);
 936         return len;
 937 }
 938
 939 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
 940 {
 941         int error = -EACCES;
 942         struct inode *inode = dentry->d_inode;
 943         struct dentry *de;
 944         struct vfsmount *mnt = NULL;
 945
 946         lock_kernel();
 947
 948         if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
 949                 goto out;
 950         error = proc_check_root(inode);
 951         if (error)
 952                 goto out;
 953
 954         error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
 955         if (error)
 956                 goto out;
 957
 958         error = do_proc_readlink(de, mnt, buffer, buflen);
 959         dput(de);
 960         mntput(mnt);
 961 out:
 962         unlock_kernel();
 963         return error;
 964 }
 965
 966 static struct inode_operations proc_pid_link_inode_operations = {
 967         .readlink       = proc_pid_readlink,
 968         .follow_link    = proc_pid_follow_link
 969 };
 970
 971 #define NUMBUF 10
 972
 973 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
 974 {
 975         struct inode *inode = filp->f_dentry->d_inode;
 976         struct task_struct *p = proc_task(inode);
 977         unsigned int fd, tid, ino;
 978         int retval;
 979         char buf[NUMBUF];
 980         struct files_struct * files;
 981
 982         retval = -ENOENT;
 983         if (!pid_alive(p))
 984                 goto out;
 985         retval = 0;
 986         tid = p->pid;
 987
 988         fd = filp->f_pos;
 989         switch (fd) {
 990                 case 0:
 991                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
 992                                 goto out;
 993                         filp->f_pos++;
 994                 case 1:
 995                         ino = fake_ino(tid, PROC_TID_INO);
 996                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
 997                                 goto out;
 998                         filp->f_pos++;
 999                 default:
1000                         files = get_files_struct(p);
1001                         if (!files)
1002                                 goto out;
1003                         spin_lock(&files->file_lock);
1004                         for (fd = filp->f_pos-2;
1005                              fd < files->max_fds;
1006                              fd++, filp->f_pos++) {
1007                                 unsigned int i,j;
1008
1009                                 if (!fcheck_files(files, fd))
1010                                         continue;
1011                                 spin_unlock(&files->file_lock);
1012
1013                                 j = NUMBUF;
1014                                 i = fd;
1015                                 do {
1016                                         j--;
1017                                         buf[j] = '0' + (i % 10);
1018                                         i /= 10;
1019                                 } while (i);
1020
1021                                 ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
1022                                 if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
1023                                         spin_lock(&files->file_lock);
1024                                         break;
1025                                 }
1026                                 spin_lock(&files->file_lock);
1027                         }
1028                         spin_unlock(&files->file_lock);
1029                         put_files_struct(files);
1030         }
1031 out:
1032         return retval;
1033 }
1034
1035 static int proc_pident_readdir(struct file *filp,
1036                 void *dirent, filldir_t filldir,
1037                 struct pid_entry *ents, unsigned int nents)
1038 {
1039         int i;
1040         int pid;
1041         struct dentry *dentry = filp->f_dentry;
1042         struct inode *inode = dentry->d_inode;
1043         struct pid_entry *p;
1044         ino_t ino;
1045         int ret;
1046
1047         ret = -ENOENT;
1048         if (!pid_alive(proc_task(inode)))
1049                 goto out;
1050
1051         ret = 0;
1052         pid = proc_task(inode)->pid;
1053         i = filp->f_pos;
1054         switch (i) {
1055         case 0:
1056                 ino = inode->i_ino;
1057                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1058                         goto out;
1059                 i++;
1060                 filp->f_pos++;
1061                 /* fall through */
1062         case 1:
1063                 ino = parent_ino(dentry);
1064                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1065                         goto out;
1066                 i++;
1067                 filp->f_pos++;
1068                 /* fall through */
1069         default:
1070                 i -= 2;
1071                 if (i >= nents) {
1072                         ret = 1;
1073                         goto out;
1074                 }
1075                 p = ents + i;
1076                 while (p->name) {
1077                         if (filldir(dirent, p->name, p->len, filp->f_pos,
1078                                     fake_ino(pid, p->type), p->mode >> 12) < 0)
1079                                 goto out;
1080                         filp->f_pos++;
1081                         p++;
1082                 }
1083         }
1084
1085         ret = 1;
1086 out:
1087         return ret;
1088 }
1089
1090 static int proc_tgid_base_readdir(struct file * filp,
1091                              void * dirent, filldir_t filldir)
1092 {
1093         return proc_pident_readdir(filp,dirent,filldir,
1094                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
1095 }
1096
1097 static int proc_tid_base_readdir(struct file * filp,
1098                              void * dirent, filldir_t filldir)
1099 {
1100         return proc_pident_readdir(filp,dirent,filldir,
1101                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
1102 }
1103
1104 /* building an inode */
1105
1106 static int task_dumpable(struct task_struct *task)
1107 {
1108         int dumpable = 0;
1109         struct mm_struct *mm;
1110
1111         task_lock(task);
1112         mm = task->mm;
1113         if (mm)
1114                 dumpable = mm->dumpable;
1115         task_unlock(task);
1116         return dumpable;
1117 }
1118
1119
1120 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
1121 {
1122         struct inode * inode;
1123         struct proc_inode *ei;
1124
1125         /* We need a new inode */
1126
1127         inode = new_inode(sb);
1128         if (!inode)
1129                 goto out;
1130
1131         /* Common stuff */
1132         ei = PROC_I(inode);
1133         ei->task = NULL;
1134         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1135         inode->i_ino = fake_ino(task->pid, ino);
1136
1137         if (!pid_alive(task))
1138                 goto out_unlock;
1139
1140         /*
1141          * grab the reference to task.
1142          */
1143         get_task_struct(task);
1144         ei->task = task;
1145         ei->type = ino;
1146         inode->i_uid = 0;
1147         inode->i_gid = 0;
1148         if (ino == PROC_TGID_INO || ino == PROC_TID_INO || task_dumpable(task)) {
1149                 inode->i_uid = task->euid;
1150                 inode->i_gid = task->egid;
1151         }
1152         security_task_to_inode(task, inode);
1153
1154 out:
1155         return inode;
1156
1157 out_unlock:
1158         ei->pde = NULL;
1159         iput(inode);
1160         return NULL;
1161 }
1162
1163 /* dentry stuff */
1164
1165 /*
1166  *      Exceptional case: normally we are not allowed to unhash a busy
1167  * directory. In this case, however, we can do it - no aliasing problems
1168  * due to the way we treat inodes.
1169  *
1170  * Rewrite the inode's ownerships here because the owning task may have
1171  * performed a setuid(), etc.
1172  */
1173 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1174 {
1175         struct inode *inode = dentry->d_inode;
1176         struct task_struct *task = proc_task(inode);
1177         if (pid_alive(task)) {
1178                 if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || task_dumpable(task)) {
1179                         inode->i_uid = task->euid;
1180                         inode->i_gid = task->egid;
1181                 } else {
1182                         inode->i_uid = 0;
1183                         inode->i_gid = 0;
1184                 }
1185                 security_task_to_inode(task, inode);
1186                 return 1;
1187         }
1188         d_drop(dentry);
1189         return 0;
1190 }
1191
1192 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1193 {
1194         struct inode *inode = dentry->d_inode;
1195         struct task_struct *task = proc_task(inode);
1196         int fd = proc_type(inode) - PROC_TID_FD_DIR;
1197         struct files_struct *files;
1198
1199         files = get_files_struct(task);
1200         if (files) {
1201                 spin_lock(&files->file_lock);
1202                 if (fcheck_files(files, fd)) {
1203                         spin_unlock(&files->file_lock);
1204                         put_files_struct(files);
1205                         if (task_dumpable(task)) {
1206                                 inode->i_uid = task->euid;
1207                                 inode->i_gid = task->egid;
1208                         } else {
1209                                 inode->i_uid = 0;
1210                                 inode->i_gid = 0;
1211                         }
1212                         security_task_to_inode(task, inode);
1213                         return 1;
1214                 }
1215                 spin_unlock(&files->file_lock);
1216                 put_files_struct(files);
1217         }
1218         d_drop(dentry);
1219         return 0;
1220 }
1221
1222 static void pid_base_iput(struct dentry *dentry, struct inode *inode)
1223 {
1224         struct task_struct *task = proc_task(inode);
1225         spin_lock(&task->proc_lock);
1226         if (task->proc_dentry == dentry)
1227                 task->proc_dentry = NULL;
1228         spin_unlock(&task->proc_lock);
1229         iput(inode);
1230 }
1231
1232 static int pid_delete_dentry(struct dentry * dentry)
1233 {
1234         /* Is the task we represent dead?
1235          * If so, then don't put the dentry on the lru list,
1236          * kill it immediately.
1237          */
1238         return !pid_alive(proc_task(dentry->d_inode));
1239 }
1240
1241 static struct dentry_operations tid_fd_dentry_operations =
1242 {
1243         .d_revalidate   = tid_fd_revalidate,
1244         .d_delete       = pid_delete_dentry,
1245 };
1246
1247 static struct dentry_operations pid_dentry_operations =
1248 {
1249         .d_revalidate   = pid_revalidate,
1250         .d_delete       = pid_delete_dentry,
1251 };
1252
1253 static struct dentry_operations pid_base_dentry_operations =
1254 {
1255         .d_revalidate   = pid_revalidate,
1256         .d_iput         = pid_base_iput,
1257         .d_delete       = pid_delete_dentry,
1258 };
1259
1260 /* Lookups */
1261
1262 static unsigned name_to_int(struct dentry *dentry)
1263 {
1264         const char *name = dentry->d_name.name;
1265         int len = dentry->d_name.len;
1266         unsigned n = 0;
1267
1268         if (len > 1 && *name == '0')
1269                 goto out;
1270         while (len-- > 0) {
1271                 unsigned c = *name++ - '0';
1272                 if (c > 9)
1273                         goto out;
1274                 if (n >= (~0U-9)/10)
1275                         goto out;
1276                 n *= 10;
1277                 n += c;
1278         }
1279         return n;
1280 out:
1281         return ~0U;
1282 }
1283
1284 /* SMP-safe */
1285 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
1286 {
1287         struct task_struct *task = proc_task(dir);
1288         unsigned fd = name_to_int(dentry);
1289         struct file * file;
1290         struct files_struct * files;
1291         struct inode *inode;
1292         struct proc_inode *ei;
1293
1294         if (fd == ~0U)
1295                 goto out;
1296         if (!pid_alive(task))
1297                 goto out;
1298
1299         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
1300         if (!inode)
1301                 goto out;
1302         ei = PROC_I(inode);
1303         files = get_files_struct(task);
1304         if (!files)
1305                 goto out_unlock;
1306         inode->i_mode = S_IFLNK;
1307         spin_lock(&files->file_lock);
1308         file = fcheck_files(files, fd);
1309         if (!file)
1310                 goto out_unlock2;
1311         if (file->f_mode & 1)
1312                 inode->i_mode |= S_IRUSR | S_IXUSR;
1313         if (file->f_mode & 2)
1314                 inode->i_mode |= S_IWUSR | S_IXUSR;
1315         spin_unlock(&files->file_lock);
1316         put_files_struct(files);
1317         inode->i_op = &proc_pid_link_inode_operations;
1318         inode->i_size = 64;
1319         ei->op.proc_get_link = proc_fd_link;
1320         dentry->d_op = &tid_fd_dentry_operations;
1321         d_add(dentry, inode);
1322         return NULL;
1323
1324 out_unlock2:
1325         spin_unlock(&files->file_lock);
1326         put_files_struct(files);
1327 out_unlock:
1328         iput(inode);
1329 out:
1330         return ERR_PTR(-ENOENT);
1331 }
1332
1333 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
1334 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
1335
1336 static struct file_operations proc_fd_operations = {
1337         .read           = generic_read_dir,
1338         .readdir        = proc_readfd,
1339 };
1340
1341 static struct file_operations proc_task_operations = {
1342         .read           = generic_read_dir,
1343         .readdir        = proc_task_readdir,
1344 };
1345
1346 /*
1347  * proc directories can do almost nothing..
1348  */
1349 static struct inode_operations proc_fd_inode_operations = {
1350         .lookup         = proc_lookupfd,
1351         .permission     = proc_permission,
1352 };
1353
1354 static struct inode_operations proc_task_inode_operations = {
1355         .lookup         = proc_task_lookup,
1356         .permission     = proc_permission,
1357 };
1358
1359 #ifdef CONFIG_SECURITY
1360 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
1361                                   size_t count, loff_t *ppos)
1362 {
1363         struct inode * inode = file->f_dentry->d_inode;
1364         unsigned long page;
1365         ssize_t length;
1366         struct task_struct *task = proc_task(inode);
1367
1368         if (count > PAGE_SIZE)
1369                 count = PAGE_SIZE;
1370         if (!(page = __get_free_page(GFP_KERNEL)))
1371                 return -ENOMEM;
1372
1373         length = security_getprocattr(task,
1374                                       (char*)file->f_dentry->d_name.name,
1375                                       (void*)page, count);
1376         if (length >= 0)
1377                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
1378         free_page(page);
1379         return length;
1380 }
1381
1382 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
1383                                    size_t count, loff_t *ppos)
1384 {
1385         struct inode * inode = file->f_dentry->d_inode;
1386         char *page;
1387         ssize_t length;
1388         struct task_struct *task = proc_task(inode);
1389
1390         if (count > PAGE_SIZE)
1391                 count = PAGE_SIZE;
1392         if (*ppos != 0) {
1393                 /* No partial writes. */
1394                 return -EINVAL;
1395         }
1396         page = (char*)__get_free_page(GFP_USER);
1397         if (!page)
1398                 return -ENOMEM;
1399         length = -EFAULT;
1400         if (copy_from_user(page, buf, count))
1401                 goto out;
1402
1403         length = security_setprocattr(task,
1404                                       (char*)file->f_dentry->d_name.name,
1405                                       (void*)page, count);
1406 out:
1407         free_page((unsigned long) page);
1408         return length;
1409 }
1410
1411 static struct file_operations proc_pid_attr_operations = {
1412         .read           = proc_pid_attr_read,
1413         .write          = proc_pid_attr_write,
1414 };
1415
1416 static struct file_operations proc_tid_attr_operations;
1417 static struct inode_operations proc_tid_attr_inode_operations;
1418 static struct file_operations proc_tgid_attr_operations;
1419 static struct inode_operations proc_tgid_attr_inode_operations;
1420 #endif
1421
1422 /* SMP-safe */
1423 static struct dentry *proc_pident_lookup(struct inode *dir,
1424                                          struct dentry *dentry,
1425                                          struct pid_entry *ents)
1426 {
1427         struct inode *inode;
1428         int error;
1429         struct task_struct *task = proc_task(dir);
1430         struct pid_entry *p;
1431         struct proc_inode *ei;
1432
1433         error = -ENOENT;
1434         inode = NULL;
1435
1436         if (!pid_alive(task))
1437                 goto out;
1438
1439         for (p = ents; p->name; p++) {
1440                 if (p->len != dentry->d_name.len)
1441                         continue;
1442                 if (!memcmp(dentry->d_name.name, p->name, p->len))
1443                         break;
1444         }
1445         if (!p->name)
1446                 goto out;
1447
1448         error = -EINVAL;
1449         inode = proc_pid_make_inode(dir->i_sb, task, p->type);
1450         if (!inode)
1451                 goto out;
1452
1453         ei = PROC_I(inode);
1454         inode->i_mode = p->mode;
1455         /*
1456          * Yes, it does not scale. And it should not. Don't add
1457          * new entries into /proc/<tgid>/ without very good reasons.
1458          */
1459         switch(p->type) {
1460                 case PROC_TGID_TASK:
1461                         inode->i_nlink = 3;
1462                         inode->i_op = &proc_task_inode_operations;
1463                         inode->i_fop = &proc_task_operations;
1464                         break;
1465                 case PROC_TID_FD:
1466                 case PROC_TGID_FD:
1467                         inode->i_nlink = 2;
1468                         inode->i_op = &proc_fd_inode_operations;
1469                         inode->i_fop = &proc_fd_operations;
1470                         break;
1471                 case PROC_TID_EXE:
1472                 case PROC_TGID_EXE:
1473                         inode->i_op = &proc_pid_link_inode_operations;
1474                         ei->op.proc_get_link = proc_exe_link;
1475                         break;
1476                 case PROC_TID_CWD:
1477                 case PROC_TGID_CWD:
1478                         inode->i_op = &proc_pid_link_inode_operations;
1479                         ei->op.proc_get_link = proc_cwd_link;
1480                         break;
1481                 case PROC_TID_ROOT:
1482                 case PROC_TGID_ROOT:
1483                         inode->i_op = &proc_pid_link_inode_operations;
1484                         ei->op.proc_get_link = proc_root_link;
1485                         break;
1486                 case PROC_TID_ENVIRON:
1487                 case PROC_TGID_ENVIRON:
1488                         inode->i_fop = &proc_info_file_operations;
1489                         ei->op.proc_read = proc_pid_environ;
1490                         break;
1491                 case PROC_TID_AUXV:
1492                 case PROC_TGID_AUXV:
1493                         inode->i_fop = &proc_info_file_operations;
1494                         ei->op.proc_read = proc_pid_auxv;
1495                         break;
1496                 case PROC_TID_STATUS:
1497                 case PROC_TGID_STATUS:
1498                         inode->i_fop = &proc_info_file_operations;
1499                         ei->op.proc_read = proc_pid_status;
1500                         break;
1501                 case PROC_TID_STAT:
1502                         inode->i_fop = &proc_info_file_operations;
1503                         ei->op.proc_read = proc_tid_stat;
1504                         break;
1505                 case PROC_TGID_STAT:
1506                         inode->i_fop = &proc_info_file_operations;
1507                         ei->op.proc_read = proc_tgid_stat;
1508                         break;
1509                 case PROC_TID_CMDLINE:
1510                 case PROC_TGID_CMDLINE:
1511                         inode->i_fop = &proc_info_file_operations;
1512                         ei->op.proc_read = proc_pid_cmdline;
1513                         break;
1514                 case PROC_TID_STATM:
1515                 case PROC_TGID_STATM:
1516                         inode->i_fop = &proc_info_file_operations;
1517                         ei->op.proc_read = proc_pid_statm;
1518                         break;
1519                 case PROC_TID_MAPS:
1520                 case PROC_TGID_MAPS:
1521                         inode->i_fop = &proc_maps_operations;
1522                         break;
1523                 case PROC_TID_MEM:
1524                 case PROC_TGID_MEM:
1525                         inode->i_op = &proc_mem_inode_operations;
1526                         inode->i_fop = &proc_mem_operations;
1527                         break;
1528 #ifdef CONFIG_SECCOMP
1529                 case PROC_TID_SECCOMP:
1530                 case PROC_TGID_SECCOMP:
1531                         inode->i_fop = &proc_seccomp_operations;
1532                         break;
1533 #endif /* CONFIG_SECCOMP */
1534                 case PROC_TID_MOUNTS:
1535                 case PROC_TGID_MOUNTS:
1536                         inode->i_fop = &proc_mounts_operations;
1537                         break;
1538 #ifdef CONFIG_SECURITY
1539                 case PROC_TID_ATTR:
1540                         inode->i_nlink = 2;
1541                         inode->i_op = &proc_tid_attr_inode_operations;
1542                         inode->i_fop = &proc_tid_attr_operations;
1543                         break;
1544                 case PROC_TGID_ATTR:
1545                         inode->i_nlink = 2;
1546                         inode->i_op = &proc_tgid_attr_inode_operations;
1547                         inode->i_fop = &proc_tgid_attr_operations;
1548                         break;
1549                 case PROC_TID_ATTR_CURRENT:
1550                 case PROC_TGID_ATTR_CURRENT:
1551                 case PROC_TID_ATTR_PREV:
1552                 case PROC_TGID_ATTR_PREV:
1553                 case PROC_TID_ATTR_EXEC:
1554                 case PROC_TGID_ATTR_EXEC:
1555                 case PROC_TID_ATTR_FSCREATE:
1556                 case PROC_TGID_ATTR_FSCREATE:
1557                         inode->i_fop = &proc_pid_attr_operations;
1558                         break;
1559 #endif
1560 #ifdef CONFIG_KALLSYMS
1561                 case PROC_TID_WCHAN:
1562                 case PROC_TGID_WCHAN:
1563                         inode->i_fop = &proc_info_file_operations;
1564                         ei->op.proc_read = proc_pid_wchan;
1565                         break;
1566 #endif
1567 #ifdef CONFIG_SCHEDSTATS
1568                 case PROC_TID_SCHEDSTAT:
1569                 case PROC_TGID_SCHEDSTAT:
1570                         inode->i_fop = &proc_info_file_operations;
1571                         ei->op.proc_read = proc_pid_schedstat;
1572                         break;
1573 #endif
1574 #ifdef CONFIG_CPUSETS
1575                 case PROC_TID_CPUSET:
1576                 case PROC_TGID_CPUSET:
1577                         inode->i_fop = &proc_cpuset_operations;
1578                         break;
1579 #endif
1580                 case PROC_TID_OOM_SCORE:
1581                 case PROC_TGID_OOM_SCORE:
1582                         inode->i_fop = &proc_info_file_operations;
1583                         ei->op.proc_read = proc_oom_score;
1584                         break;
1585                 case PROC_TID_OOM_ADJUST:
1586                 case PROC_TGID_OOM_ADJUST:
1587                         inode->i_fop = &proc_oom_adjust_operations;
1588                         break;
1589 #ifdef CONFIG_AUDITSYSCALL
1590                 case PROC_TID_LOGINUID:
1591                 case PROC_TGID_LOGINUID:
1592                         inode->i_fop = &proc_loginuid_operations;
1593                         break;
1594 #endif
1595                 default:
1596                         printk("procfs: impossible type (%d)",p->type);
1597                         iput(inode);
1598                         return ERR_PTR(-EINVAL);
1599         }
1600         dentry->d_op = &pid_dentry_operations;
1601         d_add(dentry, inode);
1602         return NULL;
1603
1604 out:
1605         return ERR_PTR(error);
1606 }
1607
1608 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1609         return proc_pident_lookup(dir, dentry, tgid_base_stuff);
1610 }
1611
1612 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1613         return proc_pident_lookup(dir, dentry, tid_base_stuff);
1614 }
1615
1616 static struct file_operations proc_tgid_base_operations = {
1617         .read           = generic_read_dir,
1618         .readdir        = proc_tgid_base_readdir,
1619 };
1620
1621 static struct file_operations proc_tid_base_operations = {
1622         .read           = generic_read_dir,
1623         .readdir        = proc_tid_base_readdir,
1624 };
1625
1626 static struct inode_operations proc_tgid_base_inode_operations = {
1627         .lookup         = proc_tgid_base_lookup,
1628 };
1629
1630 static struct inode_operations proc_tid_base_inode_operations = {
1631         .lookup         = proc_tid_base_lookup,
1632 };
1633
1634 #ifdef CONFIG_SECURITY
1635 static int proc_tgid_attr_readdir(struct file * filp,
1636                              void * dirent, filldir_t filldir)
1637 {
1638         return proc_pident_readdir(filp,dirent,filldir,
1639                                    tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
1640 }
1641
1642 static int proc_tid_attr_readdir(struct file * filp,
1643                              void * dirent, filldir_t filldir)
1644 {
1645         return proc_pident_readdir(filp,dirent,filldir,
1646                                    tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
1647 }
1648
1649 static struct file_operations proc_tgid_attr_operations = {
1650         .read           = generic_read_dir,
1651         .readdir        = proc_tgid_attr_readdir,
1652 };
1653
1654 static struct file_operations proc_tid_attr_operations = {
1655         .read           = generic_read_dir,
1656         .readdir        = proc_tid_attr_readdir,
1657 };
1658
1659 static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
1660                                 struct dentry *dentry, struct nameidata *nd)
1661 {
1662         return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
1663 }
1664
1665 static struct dentry *proc_tid_attr_lookup(struct inode *dir,
1666                                 struct dentry *dentry, struct nameidata *nd)
1667 {
1668         return proc_pident_lookup(dir, dentry, tid_attr_stuff);
1669 }
1670
1671 static struct inode_operations proc_tgid_attr_inode_operations = {
1672         .lookup         = proc_tgid_attr_lookup,
1673 };
1674
1675 static struct inode_operations proc_tid_attr_inode_operations = {
1676         .lookup         = proc_tid_attr_lookup,
1677 };
1678 #endif
1679
1680 /*
1681  * /proc/self:
1682  */
1683 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
1684                               int buflen)
1685 {
1686         char tmp[30];
1687         sprintf(tmp, "%d", current->tgid);
1688         return vfs_readlink(dentry,buffer,buflen,tmp);
1689 }
1690
1691 static int proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
1692 {
1693         char tmp[30];
1694         sprintf(tmp, "%d", current->tgid);
1695         return vfs_follow_link(nd,tmp);
1696 }
1697
1698 static struct inode_operations proc_self_inode_operations = {
1699         .readlink       = proc_self_readlink,
1700         .follow_link    = proc_self_follow_link,
1701 };
1702
1703 /**
1704  * proc_pid_unhash -  Unhash /proc/<pid> entry from the dcache.
1705  * @p: task that should be flushed.
1706  *
1707  * Drops the /proc/<pid> dcache entry from the hash chains.
1708  *
1709  * Dropping /proc/<pid> entries and detach_pid must be synchroneous,
1710  * otherwise e.g. /proc/<pid>/exe might point to the wrong executable,
1711  * if the pid value is immediately reused. This is enforced by
1712  * - caller must acquire spin_lock(p->proc_lock)
1713  * - must be called before detach_pid()
1714  * - proc_pid_lookup acquires proc_lock, and checks that
1715  *   the target is not dead by looking at the attach count
1716  *   of PIDTYPE_PID.
1717  */
1718
1719 struct dentry *proc_pid_unhash(struct task_struct *p)
1720 {
1721         struct dentry *proc_dentry;
1722
1723         proc_dentry = p->proc_dentry;
1724         if (proc_dentry != NULL) {
1725
1726                 spin_lock(&dcache_lock);
1727                 spin_lock(&proc_dentry->d_lock);
1728                 if (!d_unhashed(proc_dentry)) {
1729                         dget_locked(proc_dentry);
1730                         __d_drop(proc_dentry);
1731                         spin_unlock(&proc_dentry->d_lock);
1732                 } else {
1733                         spin_unlock(&proc_dentry->d_lock);
1734                         proc_dentry = NULL;
1735                 }
1736                 spin_unlock(&dcache_lock);
1737         }
1738         return proc_dentry;
1739 }
1740
1741 /**
1742  * proc_pid_flush - recover memory used by stale /proc/<pid>/x entries
1743  * @proc_entry: directoy to prune.
1744  *
1745  * Shrink the /proc directory that was used by the just killed thread.
1746  */
1747
1748 void proc_pid_flush(struct dentry *proc_dentry)
1749 {
1750         might_sleep();
1751         if(proc_dentry != NULL) {
1752                 shrink_dcache_parent(proc_dentry);
1753                 dput(proc_dentry);
1754         }
1755 }
1756
1757 /* SMP-safe */
1758 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1759 {
1760         struct task_struct *task;
1761         struct inode *inode;
1762         struct proc_inode *ei;
1763         unsigned tgid;
1764         int died;
1765
1766         if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
1767                 inode = new_inode(dir->i_sb);
1768                 if (!inode)
1769                         return ERR_PTR(-ENOMEM);
1770                 ei = PROC_I(inode);
1771                 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1772                 inode->i_ino = fake_ino(0, PROC_TGID_INO);
1773                 ei->pde = NULL;
1774                 inode->i_mode = S_IFLNK|S_IRWXUGO;
1775                 inode->i_uid = inode->i_gid = 0;
1776                 inode->i_size = 64;
1777                 inode->i_op = &proc_self_inode_operations;
1778                 d_add(dentry, inode);
1779                 return NULL;
1780         }
1781         tgid = name_to_int(dentry);
1782         if (tgid == ~0U)
1783                 goto out;
1784
1785         read_lock(&tasklist_lock);
1786         task = find_task_by_pid(tgid);
1787         if (task)
1788                 get_task_struct(task);
1789         read_unlock(&tasklist_lock);
1790         if (!task)
1791                 goto out;
1792
1793         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
1794
1795
1796         if (!inode) {
1797                 put_task_struct(task);
1798                 goto out;
1799         }
1800         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
1801         inode->i_op = &proc_tgid_base_inode_operations;
1802         inode->i_fop = &proc_tgid_base_operations;
1803         inode->i_nlink = 3;
1804         inode->i_flags|=S_IMMUTABLE;
1805
1806         dentry->d_op = &pid_base_dentry_operations;
1807
1808         died = 0;
1809         d_add(dentry, inode);
1810         spin_lock(&task->proc_lock);
1811         task->proc_dentry = dentry;
1812         if (!pid_alive(task)) {
1813                 dentry = proc_pid_unhash(task);
1814                 died = 1;
1815         }
1816         spin_unlock(&task->proc_lock);
1817
1818         put_task_struct(task);
1819         if (died) {
1820                 proc_pid_flush(dentry);
1821                 goto out;
1822         }
1823         return NULL;
1824 out:
1825         return ERR_PTR(-ENOENT);
1826 }
1827
1828 /* SMP-safe */
1829 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1830 {
1831         struct task_struct *task;
1832         struct task_struct *leader = proc_task(dir);
1833         struct inode *inode;
1834         unsigned tid;
1835
1836         tid = name_to_int(dentry);
1837         if (tid == ~0U)
1838                 goto out;
1839
1840         read_lock(&tasklist_lock);
1841         task = find_task_by_pid(tid);
1842         if (task)
1843                 get_task_struct(task);
1844         read_unlock(&tasklist_lock);
1845         if (!task)
1846                 goto out;
1847         if (leader->tgid != task->tgid)
1848                 goto out_drop_task;
1849
1850         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);
1851
1852
1853         if (!inode)
1854                 goto out_drop_task;
1855         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
1856         inode->i_op = &proc_tid_base_inode_operations;
1857         inode->i_fop = &proc_tid_base_operations;
1858         inode->i_nlink = 3;
1859         inode->i_flags|=S_IMMUTABLE;
1860
1861         dentry->d_op = &pid_base_dentry_operations;
1862
1863         d_add(dentry, inode);
1864
1865         put_task_struct(task);
1866         return NULL;
1867 out_drop_task:
1868         put_task_struct(task);
1869 out:
1870         return ERR_PTR(-ENOENT);
1871 }
1872
1873 #define PROC_NUMBUF 10
1874 #define PROC_MAXPIDS 20
1875
1876 /*
1877  * Get a few tgid's to return for filldir - we need to hold the
1878  * tasklist lock while doing this, and we must release it before
1879  * we actually do the filldir itself, so we use a temp buffer..
1880  */
1881 static int get_tgid_list(int index, unsigned long version, unsigned int *tgids)
1882 {
1883         struct task_struct *p;
1884         int nr_tgids = 0;
1885
1886         index--;
1887         read_lock(&tasklist_lock);
1888         p = NULL;
1889         if (version) {
1890                 p = find_task_by_pid(version);
1891                 if (p && !thread_group_leader(p))
1892                         p = NULL;
1893         }
1894
1895         if (p)
1896                 index = 0;
1897         else
1898                 p = next_task(&init_task);
1899
1900         for ( ; p != &init_task; p = next_task(p)) {
1901                 int tgid = p->pid;
1902                 if (!pid_alive(p))
1903                         continue;
1904                 if (--index >= 0)
1905                         continue;
1906                 tgids[nr_tgids] = tgid;
1907                 nr_tgids++;
1908                 if (nr_tgids >= PROC_MAXPIDS)
1909                         break;
1910         }
1911         read_unlock(&tasklist_lock);
1912         return nr_tgids;
1913 }
1914
1915 /*
1916  * Get a few tid's to return for filldir - we need to hold the
1917  * tasklist lock while doing this, and we must release it before
1918  * we actually do the filldir itself, so we use a temp buffer..
1919  */
1920 static int get_tid_list(int index, unsigned int *tids, struct inode *dir)
1921 {
1922         struct task_struct *leader_task = proc_task(dir);
1923         struct task_struct *task = leader_task;
1924         int nr_tids = 0;
1925
1926         index -= 2;
1927         read_lock(&tasklist_lock);
1928         /*
1929          * The starting point task (leader_task) might be an already
1930          * unlinked task, which cannot be used to access the task-list
1931          * via next_thread().
1932          */
1933         if (pid_alive(task)) do {
1934                 int tid = task->pid;
1935
1936                 if (--index >= 0)
1937                         continue;
1938                 tids[nr_tids] = tid;
1939                 nr_tids++;
1940                 if (nr_tids >= PROC_MAXPIDS)
1941                         break;
1942         } while ((task = next_thread(task)) != leader_task);
1943         read_unlock(&tasklist_lock);
1944         return nr_tids;
1945 }
1946
1947 /* for the /proc/ directory itself, after non-process stuff has been done */
1948 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
1949 {
1950         unsigned int tgid_array[PROC_MAXPIDS];
1951         char buf[PROC_NUMBUF];
1952         unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
1953         unsigned int nr_tgids, i;
1954         int next_tgid;
1955
1956         if (!nr) {
1957                 ino_t ino = fake_ino(0,PROC_TGID_INO);
1958                 if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
1959                         return 0;
1960                 filp->f_pos++;
1961                 nr++;
1962         }
1963
1964         /* f_version caches the tgid value that the last readdir call couldn't
1965          * return. lseek aka telldir automagically resets f_version to 0.
1966          */
1967         next_tgid = filp->f_version;
1968         filp->f_version = 0;
1969         for (;;) {
1970                 nr_tgids = get_tgid_list(nr, next_tgid, tgid_array);
1971                 if (!nr_tgids) {
1972                         /* no more entries ! */
1973                         break;
1974                 }
1975                 next_tgid = 0;
1976
1977                 /* do not use the last found pid, reserve it for next_tgid */
1978                 if (nr_tgids == PROC_MAXPIDS) {
1979                         nr_tgids--;
1980                         next_tgid = tgid_array[nr_tgids];
1981                 }
1982
1983                 for (i=0;i<nr_tgids;i++) {
1984                         int tgid = tgid_array[i];
1985                         ino_t ino = fake_ino(tgid,PROC_TGID_INO);
1986                         unsigned long j = PROC_NUMBUF;
1987
1988                         do
1989                                 buf[--j] = '0' + (tgid % 10);
1990                         while ((tgid /= 10) != 0);
1991
1992                         if (filldir(dirent, buf+j, PROC_NUMBUF-j, filp->f_pos, ino, DT_DIR) < 0) {
1993                                 /* returning this tgid failed, save it as the first
1994                                  * pid for the next readir call */
1995                                 filp->f_version = tgid_array[i];
1996                                 goto out;
1997                         }
1998                         filp->f_pos++;
1999                         nr++;
2000                 }
2001         }
2002 out:
2003         return 0;
2004 }
2005
2006 /* for the /proc/TGID/task/ directories */
2007 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
2008 {
2009         unsigned int tid_array[PROC_MAXPIDS];
2010         char buf[PROC_NUMBUF];
2011         unsigned int nr_tids, i;
2012         struct dentry *dentry = filp->f_dentry;
2013         struct inode *inode = dentry->d_inode;
2014         int retval = -ENOENT;
2015         ino_t ino;
2016         unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
2017
2018         if (!pid_alive(proc_task(inode)))
2019                 goto out;
2020         retval = 0;
2021
2022         switch (pos) {
2023         case 0:
2024                 ino = inode->i_ino;
2025                 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
2026                         goto out;
2027                 pos++;
2028                 /* fall through */
2029         case 1:
2030                 ino = parent_ino(dentry);
2031                 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
2032                         goto out;
2033                 pos++;
2034                 /* fall through */
2035         }
2036
2037         nr_tids = get_tid_list(pos, tid_array, inode);
2038
2039         for (i = 0; i < nr_tids; i++) {
2040                 unsigned long j = PROC_NUMBUF;
2041                 int tid = tid_array[i];
2042
2043                 ino = fake_ino(tid,PROC_TID_INO);
2044
2045                 do
2046                         buf[--j] = '0' + (tid % 10);
2047                 while ((tid /= 10) != 0);
2048
2049                 if (filldir(dirent, buf+j, PROC_NUMBUF-j, pos, ino, DT_DIR) < 0)
2050                         break;
2051                 pos++;
2052         }
2053 out:
2054         filp->f_pos = pos;
2055         return retval;
2056 }