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/task_io_accounting_ops.h>
  57 #include <linux/init.h>
  58 #include <linux/capability.h>
  59 #include <linux/file.h>
  60 #include <linux/fdtable.h>
  61 #include <linux/string.h>
  62 #include <linux/seq_file.h>
  63 #include <linux/namei.h>
  64 #include <linux/mnt_namespace.h>
  65 #include <linux/mm.h>
  66 #include <linux/swap.h>
  67 #include <linux/rcupdate.h>
  68 #include <linux/kallsyms.h>
  69 #include <linux/stacktrace.h>
  70 #include <linux/resource.h>
  71 #include <linux/module.h>
  72 #include <linux/mount.h>
  73 #include <linux/security.h>
  74 #include <linux/ptrace.h>
  75 #include <linux/tracehook.h>
  76 #include <linux/cgroup.h>
  77 #include <linux/cpuset.h>
  78 #include <linux/audit.h>
  79 #include <linux/poll.h>
  80 #include <linux/nsproxy.h>
  81 #include <linux/oom.h>
  82 #include <linux/elf.h>
  83 #include <linux/pid_namespace.h>
  84 #include <linux/fs_struct.h>
  85 #include <linux/slab.h>
  86 #include "internal.h"
  87
  88 /* NOTE:
  89  *      Implementing inode permission operations in /proc is almost
  90  *      certainly an error.  Permission checks need to happen during
  91  *      each system call not at open time.  The reason is that most of
  92  *      what we wish to check for permissions in /proc varies at runtime.
  93  *
  94  *      The classic example of a problem is opening file descriptors
  95  *      in /proc for a task before it execs a suid executable.
  96  */
  97
  98 struct pid_entry {
  99         char *name;
 100         int len;
 101         mode_t mode;
 102         const struct inode_operations *iop;
 103         const struct file_operations *fop;
 104         union proc_op op;
 105 };
 106
 107 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 108         .name = (NAME),                                 \
 109         .len  = sizeof(NAME) - 1,                       \
 110         .mode = MODE,                                   \
 111         .iop  = IOP,                                    \
 112         .fop  = FOP,                                    \
 113         .op   = OP,                                     \
 114 }
 115
 116 #define DIR(NAME, MODE, iops, fops)     \
 117         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 118 #define LNK(NAME, get_link)                                     \
 119         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 120                 &proc_pid_link_inode_operations, NULL,          \
 121                 { .proc_get_link = get_link } )
 122 #define REG(NAME, MODE, fops)                           \
 123         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 124 #define INF(NAME, MODE, read)                           \
 125         NOD(NAME, (S_IFREG|(MODE)),                     \
 126                 NULL, &proc_info_file_operations,       \
 127                 { .proc_read = read } )
 128 #define ONE(NAME, MODE, show)                           \
 129         NOD(NAME, (S_IFREG|(MODE)),                     \
 130                 NULL, &proc_single_file_operations,     \
 131                 { .proc_show = show } )
 132
 133 /*
 134  * Count the number of hardlinks for the pid_entry table, excluding the .
 135  * and .. links.
 136  */
 137 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
 138         unsigned int n)
 139 {
 140         unsigned int i;
 141         unsigned int count;
 142
 143         count = 0;
 144         for (i = 0; i < n; ++i) {
 145                 if (S_ISDIR(entries[i].mode))
 146                         ++count;
 147         }
 148
 149         return count;
 150 }
 151
 152 static int get_task_root(struct task_struct *task, struct path *root)
 153 {
 154         int result = -ENOENT;
 155
 156         task_lock(task);
 157         if (task->fs) {
 158                 get_fs_root(task->fs, root);
 159                 result = 0;
 160         }
 161         task_unlock(task);
 162         return result;
 163 }
 164
 165 static int proc_cwd_link(struct inode *inode, struct path *path)
 166 {
 167         struct task_struct *task = get_proc_task(inode);
 168         int result = -ENOENT;
 169
 170         if (task) {
 171                 task_lock(task);
 172                 if (task->fs) {
 173                         get_fs_pwd(task->fs, path);
 174                         result = 0;
 175                 }
 176                 task_unlock(task);
 177                 put_task_struct(task);
 178         }
 179         return result;
 180 }
 181
 182 static int proc_root_link(struct inode *inode, struct path *path)
 183 {
 184         struct task_struct *task = get_proc_task(inode);
 185         int result = -ENOENT;
 186
 187         if (task) {
 188                 result = get_task_root(task, path);
 189                 put_task_struct(task);
 190         }
 191         return result;
 192 }
 193
 194 /*
 195  * Return zero if current may access user memory in @task, -error if not.
 196  */
 197 static int check_mem_permission(struct task_struct *task)
 198 {
 199         /*
 200          * A task can always look at itself, in case it chooses
 201          * to use system calls instead of load instructions.
 202          */
 203         if (task == current)
 204                 return 0;
 205
 206         /*
 207          * If current is actively ptrace'ing, and would also be
 208          * permitted to freshly attach with ptrace now, permit it.
 209          */
 210         if (task_is_stopped_or_traced(task)) {
 211                 int match;
 212                 rcu_read_lock();
 213                 match = (tracehook_tracer_task(task) == current);
 214                 rcu_read_unlock();
 215                 if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
 216                         return 0;
 217         }
 218
 219         /*
 220          * Noone else is allowed.
 221          */
 222         return -EPERM;
 223 }
 224
 225 struct mm_struct *mm_for_maps(struct task_struct *task)
 226 {
 227         struct mm_struct *mm;
 228
 229         if (mutex_lock_killable(&task->signal->cred_guard_mutex))
 230                 return NULL;
 231
 232         mm = get_task_mm(task);
 233         if (mm && mm != current->mm &&
 234                         !ptrace_may_access(task, PTRACE_MODE_READ)) {
 235                 mmput(mm);
 236                 mm = NULL;
 237         }
 238         mutex_unlock(&task->signal->cred_guard_mutex);
 239
 240         return mm;
 241 }
 242
 243 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 244 {
 245         int res = 0;
 246         unsigned int len;
 247         struct mm_struct *mm = get_task_mm(task);
 248         if (!mm)
 249                 goto out;
 250         if (!mm->arg_end)
 251                 goto out_mm;    /* Shh! No looking before we're done */
 252
 253         len = mm->arg_end - mm->arg_start;
 254
 255         if (len > PAGE_SIZE)
 256                 len = PAGE_SIZE;
 257
 258         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 259
 260         // If the nul at the end of args has been overwritten, then
 261         // assume application is using setproctitle(3).
 262         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 263                 len = strnlen(buffer, res);
 264                 if (len < res) {
 265                     res = len;
 266                 } else {
 267                         len = mm->env_end - mm->env_start;
 268                         if (len > PAGE_SIZE - res)
 269                                 len = PAGE_SIZE - res;
 270                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 271                         res = strnlen(buffer, res);
 272                 }
 273         }
 274 out_mm:
 275         mmput(mm);
 276 out:
 277         return res;
 278 }
 279
 280 static int proc_pid_auxv(struct task_struct *task, char *buffer)
 281 {
 282         int res = 0;
 283         struct mm_struct *mm = get_task_mm(task);
 284         if (mm) {
 285                 unsigned int nwords = 0;
 286                 do {
 287                         nwords += 2;
 288                 } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 289                 res = nwords * sizeof(mm->saved_auxv[0]);
 290                 if (res > PAGE_SIZE)
 291                         res = PAGE_SIZE;
 292                 memcpy(buffer, mm->saved_auxv, res);
 293                 mmput(mm);
 294         }
 295         return res;
 296 }
 297
 298
 299 #ifdef CONFIG_KALLSYMS
 300 /*
 301  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 302  * Returns the resolved symbol.  If that fails, simply return the address.
 303  */
 304 static int proc_pid_wchan(struct task_struct *task, char *buffer)
 305 {
 306         unsigned long wchan;
 307         char symname[KSYM_NAME_LEN];
 308
 309         wchan = get_wchan(task);
 310
 311         if (lookup_symbol_name(wchan, symname) < 0)
 312                 if (!ptrace_may_access(task, PTRACE_MODE_READ))
 313                         return 0;
 314                 else
 315                         return sprintf(buffer, "%lu", wchan);
 316         else
 317                 return sprintf(buffer, "%s", symname);
 318 }
 319 #endif /* CONFIG_KALLSYMS */
 320
 321 #ifdef CONFIG_STACKTRACE
 322
 323 #define MAX_STACK_TRACE_DEPTH   64
 324
 325 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 326                           struct pid *pid, struct task_struct *task)
 327 {
 328         struct stack_trace trace;
 329         unsigned long *entries;
 330         int i;
 331
 332         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 333         if (!entries)
 334                 return -ENOMEM;
 335
 336         trace.nr_entries        = 0;
 337         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 338         trace.entries           = entries;
 339         trace.skip              = 0;
 340         save_stack_trace_tsk(task, &trace);
 341
 342         for (i = 0; i < trace.nr_entries; i++) {
 343                 seq_printf(m, "[<%p>] %pS\n",
 344                            (void *)entries[i], (void *)entries[i]);
 345         }
 346         kfree(entries);
 347
 348         return 0;
 349 }
 350 #endif
 351
 352 #ifdef CONFIG_SCHEDSTATS
 353 /*
 354  * Provides /proc/PID/schedstat
 355  */
 356 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 357 {
 358         return sprintf(buffer, "%llu %llu %lu\n",
 359                         (unsigned long long)task->se.sum_exec_runtime,
 360                         (unsigned long long)task->sched_info.run_delay,
 361                         task->sched_info.pcount);
 362 }
 363 #endif
 364
 365 #ifdef CONFIG_LATENCYTOP
 366 static int lstats_show_proc(struct seq_file *m, void *v)
 367 {
 368         int i;
 369         struct inode *inode = m->private;
 370         struct task_struct *task = get_proc_task(inode);
 371
 372         if (!task)
 373                 return -ESRCH;
 374         seq_puts(m, "Latency Top version : v0.1\n");
 375         for (i = 0; i < 32; i++) {
 376                 if (task->latency_record[i].backtrace[0]) {
 377                         int q;
 378                         seq_printf(m, "%i %li %li ",
 379                                 task->latency_record[i].count,
 380                                 task->latency_record[i].time,
 381                                 task->latency_record[i].max);
 382                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 383                                 char sym[KSYM_SYMBOL_LEN];
 384                                 char *c;
 385                                 if (!task->latency_record[i].backtrace[q])
 386                                         break;
 387                                 if (task->latency_record[i].backtrace[q] == ULONG_MAX)
 388                                         break;
 389                                 sprint_symbol(sym, task->latency_record[i].backtrace[q]);
 390                                 c = strchr(sym, '+');
 391                                 if (c)
 392                                         *c = 0;
 393                                 seq_printf(m, "%s ", sym);
 394                         }
 395                         seq_printf(m, "\n");
 396                 }
 397
 398         }
 399         put_task_struct(task);
 400         return 0;
 401 }
 402
 403 static int lstats_open(struct inode *inode, struct file *file)
 404 {
 405         return single_open(file, lstats_show_proc, inode);
 406 }
 407
 408 static ssize_t lstats_write(struct file *file, const char __user *buf,
 409                             size_t count, loff_t *offs)
 410 {
 411         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 412
 413         if (!task)
 414                 return -ESRCH;
 415         clear_all_latency_tracing(task);
 416         put_task_struct(task);
 417
 418         return count;
 419 }
 420
 421 static const struct file_operations proc_lstats_operations = {
 422         .open           = lstats_open,
 423         .read           = seq_read,
 424         .write          = lstats_write,
 425         .llseek         = seq_lseek,
 426         .release        = single_release,
 427 };
 428
 429 #endif
 430
 431 static int proc_oom_score(struct task_struct *task, char *buffer)
 432 {
 433         unsigned long points = 0;
 434
 435         read_lock(&tasklist_lock);
 436         if (pid_alive(task))
 437                 points = oom_badness(task, NULL, NULL,
 438                                         totalram_pages + total_swap_pages);
 439         read_unlock(&tasklist_lock);
 440         return sprintf(buffer, "%lu\n", points);
 441 }
 442
 443 struct limit_names {
 444         char *name;
 445         char *unit;
 446 };
 447
 448 static const struct limit_names lnames[RLIM_NLIMITS] = {
 449         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 450         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 451         [RLIMIT_DATA] = {"Max data size", "bytes"},
 452         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 453         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 454         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 455         [RLIMIT_NPROC] = {"Max processes", "processes"},
 456         [RLIMIT_NOFILE] = {"Max open files", "files"},
 457         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 458         [RLIMIT_AS] = {"Max address space", "bytes"},
 459         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 460         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 461         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 462         [RLIMIT_NICE] = {"Max nice priority", NULL},
 463         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 464         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 465 };
 466
 467 /* Display limits for a process */
 468 static int proc_pid_limits(struct task_struct *task, char *buffer)
 469 {
 470         unsigned int i;
 471         int count = 0;
 472         unsigned long flags;
 473         char *bufptr = buffer;
 474
 475         struct rlimit rlim[RLIM_NLIMITS];
 476
 477         if (!lock_task_sighand(task, &flags))
 478                 return 0;
 479         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 480         unlock_task_sighand(task, &flags);
 481
 482         /*
 483          * print the file header
 484          */
 485         count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
 486                         "Limit", "Soft Limit", "Hard Limit", "Units");
 487
 488         for (i = 0; i < RLIM_NLIMITS; i++) {
 489                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 490                         count += sprintf(&bufptr[count], "%-25s %-20s ",
 491                                          lnames[i].name, "unlimited");
 492                 else
 493                         count += sprintf(&bufptr[count], "%-25s %-20lu ",
 494                                          lnames[i].name, rlim[i].rlim_cur);
 495
 496                 if (rlim[i].rlim_max == RLIM_INFINITY)
 497                         count += sprintf(&bufptr[count], "%-20s ", "unlimited");
 498                 else
 499                         count += sprintf(&bufptr[count], "%-20lu ",
 500                                          rlim[i].rlim_max);
 501
 502                 if (lnames[i].unit)
 503                         count += sprintf(&bufptr[count], "%-10s\n",
 504                                          lnames[i].unit);
 505                 else
 506                         count += sprintf(&bufptr[count], "\n");
 507         }
 508
 509         return count;
 510 }
 511
 512 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 513 static int proc_pid_syscall(struct task_struct *task, char *buffer)
 514 {
 515         long nr;
 516         unsigned long args[6], sp, pc;
 517
 518         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 519                 return sprintf(buffer, "running\n");
 520
 521         if (nr < 0)
 522                 return sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 523
 524         return sprintf(buffer,
 525                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 526                        nr,
 527                        args[0], args[1], args[2], args[3], args[4], args[5],
 528                        sp, pc);
 529 }
 530 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 531
 532 /************************************************************************/
 533 /*                       Here the fs part begins                        */
 534 /************************************************************************/
 535
 536 /* permission checks */
 537 static int proc_fd_access_allowed(struct inode *inode)
 538 {
 539         struct task_struct *task;
 540         int allowed = 0;
 541         /* Allow access to a task's file descriptors if it is us or we
 542          * may use ptrace attach to the process and find out that
 543          * information.
 544          */
 545         task = get_proc_task(inode);
 546         if (task) {
 547                 allowed = ptrace_may_access(task, PTRACE_MODE_READ);
 548                 put_task_struct(task);
 549         }
 550         return allowed;
 551 }
 552
 553 static int proc_setattr(struct dentry *dentry, struct iattr *attr)
 554 {
 555         int error;
 556         struct inode *inode = dentry->d_inode;
 557
 558         if (attr->ia_valid & ATTR_MODE)
 559                 return -EPERM;
 560
 561         error = inode_change_ok(inode, attr);
 562         if (error)
 563                 return error;
 564
 565         if ((attr->ia_valid & ATTR_SIZE) &&
 566             attr->ia_size != i_size_read(inode)) {
 567                 error = vmtruncate(inode, attr->ia_size);
 568                 if (error)
 569                         return error;
 570         }
 571
 572         setattr_copy(inode, attr);
 573         mark_inode_dirty(inode);
 574         return 0;
 575 }
 576
 577 static const struct inode_operations proc_def_inode_operations = {
 578         .setattr        = proc_setattr,
 579 };
 580
 581 static int mounts_open_common(struct inode *inode, struct file *file,
 582                               const struct seq_operations *op)
 583 {
 584         struct task_struct *task = get_proc_task(inode);
 585         struct nsproxy *nsp;
 586         struct mnt_namespace *ns = NULL;
 587         struct path root;
 588         struct proc_mounts *p;
 589         int ret = -EINVAL;
 590
 591         if (task) {
 592                 rcu_read_lock();
 593                 nsp = task_nsproxy(task);
 594                 if (nsp) {
 595                         ns = nsp->mnt_ns;
 596                         if (ns)
 597                                 get_mnt_ns(ns);
 598                 }
 599                 rcu_read_unlock();
 600                 if (ns && get_task_root(task, &root) == 0)
 601                         ret = 0;
 602                 put_task_struct(task);
 603         }
 604
 605         if (!ns)
 606                 goto err;
 607         if (ret)
 608                 goto err_put_ns;
 609
 610         ret = -ENOMEM;
 611         p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
 612         if (!p)
 613                 goto err_put_path;
 614
 615         file->private_data = &p->m;
 616         ret = seq_open(file, op);
 617         if (ret)
 618                 goto err_free;
 619
 620         p->m.private = p;
 621         p->ns = ns;
 622         p->root = root;
 623         p->event = ns->event;
 624
 625         return 0;
 626
 627  err_free:
 628         kfree(p);
 629  err_put_path:
 630         path_put(&root);
 631  err_put_ns:
 632         put_mnt_ns(ns);
 633  err:
 634         return ret;
 635 }
 636
 637 static int mounts_release(struct inode *inode, struct file *file)
 638 {
 639         struct proc_mounts *p = file->private_data;
 640         path_put(&p->root);
 641         put_mnt_ns(p->ns);
 642         return seq_release(inode, file);
 643 }
 644
 645 static unsigned mounts_poll(struct file *file, poll_table *wait)
 646 {
 647         struct proc_mounts *p = file->private_data;
 648         unsigned res = POLLIN | POLLRDNORM;
 649
 650         poll_wait(file, &p->ns->poll, wait);
 651         if (mnt_had_events(p))
 652                 res |= POLLERR | POLLPRI;
 653
 654         return res;
 655 }
 656
 657 static int mounts_open(struct inode *inode, struct file *file)
 658 {
 659         return mounts_open_common(inode, file, &mounts_op);
 660 }
 661
 662 static const struct file_operations proc_mounts_operations = {
 663         .open           = mounts_open,
 664         .read           = seq_read,
 665         .llseek         = seq_lseek,
 666         .release        = mounts_release,
 667         .poll           = mounts_poll,
 668 };
 669
 670 static int mountinfo_open(struct inode *inode, struct file *file)
 671 {
 672         return mounts_open_common(inode, file, &mountinfo_op);
 673 }
 674
 675 static const struct file_operations proc_mountinfo_operations = {
 676         .open           = mountinfo_open,
 677         .read           = seq_read,
 678         .llseek         = seq_lseek,
 679         .release        = mounts_release,
 680         .poll           = mounts_poll,
 681 };
 682
 683 static int mountstats_open(struct inode *inode, struct file *file)
 684 {
 685         return mounts_open_common(inode, file, &mountstats_op);
 686 }
 687
 688 static const struct file_operations proc_mountstats_operations = {
 689         .open           = mountstats_open,
 690         .read           = seq_read,
 691         .llseek         = seq_lseek,
 692         .release        = mounts_release,
 693 };
 694
 695 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 696
 697 static ssize_t proc_info_read(struct file * file, char __user * buf,
 698                           size_t count, loff_t *ppos)
 699 {
 700         struct inode * inode = file->f_path.dentry->d_inode;
 701         unsigned long page;
 702         ssize_t length;
 703         struct task_struct *task = get_proc_task(inode);
 704
 705         length = -ESRCH;
 706         if (!task)
 707                 goto out_no_task;
 708
 709         if (count > PROC_BLOCK_SIZE)
 710                 count = PROC_BLOCK_SIZE;
 711
 712         length = -ENOMEM;
 713         if (!(page = __get_free_page(GFP_TEMPORARY)))
 714                 goto out;
 715
 716         length = PROC_I(inode)->op.proc_read(task, (char*)page);
 717
 718         if (length >= 0)
 719                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 720         free_page(page);
 721 out:
 722         put_task_struct(task);
 723 out_no_task:
 724         return length;
 725 }
 726
 727 static const struct file_operations proc_info_file_operations = {
 728         .read           = proc_info_read,
 729         .llseek         = generic_file_llseek,
 730 };
 731
 732 static int proc_single_show(struct seq_file *m, void *v)
 733 {
 734         struct inode *inode = m->private;
 735         struct pid_namespace *ns;
 736         struct pid *pid;
 737         struct task_struct *task;
 738         int ret;
 739
 740         ns = inode->i_sb->s_fs_info;
 741         pid = proc_pid(inode);
 742         task = get_pid_task(pid, PIDTYPE_PID);
 743         if (!task)
 744                 return -ESRCH;
 745
 746         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 747
 748         put_task_struct(task);
 749         return ret;
 750 }
 751
 752 static int proc_single_open(struct inode *inode, struct file *filp)
 753 {
 754         int ret;
 755         ret = single_open(filp, proc_single_show, NULL);
 756         if (!ret) {
 757                 struct seq_file *m = filp->private_data;
 758
 759                 m->private = inode;
 760         }
 761         return ret;
 762 }
 763
 764 static const struct file_operations proc_single_file_operations = {
 765         .open           = proc_single_open,
 766         .read           = seq_read,
 767         .llseek         = seq_lseek,
 768         .release        = single_release,
 769 };
 770
 771 static int mem_open(struct inode* inode, struct file* file)
 772 {
 773         file->private_data = (void*)((long)current->self_exec_id);
 774         /* OK to pass negative loff_t, we can catch out-of-range */
 775         file->f_mode |= FMODE_UNSIGNED_OFFSET;
 776         return 0;
 777 }
 778
 779 static ssize_t mem_read(struct file * file, char __user * buf,
 780                         size_t count, loff_t *ppos)
 781 {
 782         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 783         char *page;
 784         unsigned long src = *ppos;
 785         int ret = -ESRCH;
 786         struct mm_struct *mm;
 787
 788         if (!task)
 789                 goto out_no_task;
 790
 791         if (check_mem_permission(task))
 792                 goto out;
 793
 794         ret = -ENOMEM;
 795         page = (char *)__get_free_page(GFP_TEMPORARY);
 796         if (!page)
 797                 goto out;
 798
 799         ret = 0;
 800
 801         mm = get_task_mm(task);
 802         if (!mm)
 803                 goto out_free;
 804
 805         ret = -EIO;
 806
 807         if (file->private_data != (void*)((long)current->self_exec_id))
 808                 goto out_put;
 809
 810         ret = 0;
 811
 812         while (count > 0) {
 813                 int this_len, retval;
 814
 815                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 816                 retval = access_process_vm(task, src, page, this_len, 0);
 817                 if (!retval || check_mem_permission(task)) {
 818                         if (!ret)
 819                                 ret = -EIO;
 820                         break;
 821                 }
 822
 823                 if (copy_to_user(buf, page, retval)) {
 824                         ret = -EFAULT;
 825                         break;
 826                 }
 827
 828                 ret += retval;
 829                 src += retval;
 830                 buf += retval;
 831                 count -= retval;
 832         }
 833         *ppos = src;
 834
 835 out_put:
 836         mmput(mm);
 837 out_free:
 838         free_page((unsigned long) page);
 839 out:
 840         put_task_struct(task);
 841 out_no_task:
 842         return ret;
 843 }
 844
 845 #define mem_write NULL
 846
 847 #ifndef mem_write
 848 /* This is a security hazard */
 849 static ssize_t mem_write(struct file * file, const char __user *buf,
 850                          size_t count, loff_t *ppos)
 851 {
 852         int copied;
 853         char *page;
 854         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 855         unsigned long dst = *ppos;
 856
 857         copied = -ESRCH;
 858         if (!task)
 859                 goto out_no_task;
 860
 861         if (check_mem_permission(task))
 862                 goto out;
 863
 864         copied = -ENOMEM;
 865         page = (char *)__get_free_page(GFP_TEMPORARY);
 866         if (!page)
 867                 goto out;
 868
 869         copied = 0;
 870         while (count > 0) {
 871                 int this_len, retval;
 872
 873                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 874                 if (copy_from_user(page, buf, this_len)) {
 875                         copied = -EFAULT;
 876                         break;
 877                 }
 878                 retval = access_process_vm(task, dst, page, this_len, 1);
 879                 if (!retval) {
 880                         if (!copied)
 881                                 copied = -EIO;
 882                         break;
 883                 }
 884                 copied += retval;
 885                 buf += retval;
 886                 dst += retval;
 887                 count -= retval;
 888         }
 889         *ppos = dst;
 890         free_page((unsigned long) page);
 891 out:
 892         put_task_struct(task);
 893 out_no_task:
 894         return copied;
 895 }
 896 #endif
 897
 898 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 899 {
 900         switch (orig) {
 901         case 0:
 902                 file->f_pos = offset;
 903                 break;
 904         case 1:
 905                 file->f_pos += offset;
 906                 break;
 907         default:
 908                 return -EINVAL;
 909         }
 910         force_successful_syscall_return();
 911         return file->f_pos;
 912 }
 913
 914 static const struct file_operations proc_mem_operations = {
 915         .llseek         = mem_lseek,
 916         .read           = mem_read,
 917         .write          = mem_write,
 918         .open           = mem_open,
 919 };
 920
 921 static ssize_t environ_read(struct file *file, char __user *buf,
 922                         size_t count, loff_t *ppos)
 923 {
 924         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 925         char *page;
 926         unsigned long src = *ppos;
 927         int ret = -ESRCH;
 928         struct mm_struct *mm;
 929
 930         if (!task)
 931                 goto out_no_task;
 932
 933         if (!ptrace_may_access(task, PTRACE_MODE_READ))
 934                 goto out;
 935
 936         ret = -ENOMEM;
 937         page = (char *)__get_free_page(GFP_TEMPORARY);
 938         if (!page)
 939                 goto out;
 940
 941         ret = 0;
 942
 943         mm = get_task_mm(task);
 944         if (!mm)
 945                 goto out_free;
 946
 947         while (count > 0) {
 948                 int this_len, retval, max_len;
 949
 950                 this_len = mm->env_end - (mm->env_start + src);
 951
 952                 if (this_len <= 0)
 953                         break;
 954
 955                 max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 956                 this_len = (this_len > max_len) ? max_len : this_len;
 957
 958                 retval = access_process_vm(task, (mm->env_start + src),
 959                         page, this_len, 0);
 960
 961                 if (retval <= 0) {
 962                         ret = retval;
 963                         break;
 964                 }
 965
 966                 if (copy_to_user(buf, page, retval)) {
 967                         ret = -EFAULT;
 968                         break;
 969                 }
 970
 971                 ret += retval;
 972                 src += retval;
 973                 buf += retval;
 974                 count -= retval;
 975         }
 976         *ppos = src;
 977
 978         mmput(mm);
 979 out_free:
 980         free_page((unsigned long) page);
 981 out:
 982         put_task_struct(task);
 983 out_no_task:
 984         return ret;
 985 }
 986
 987 static const struct file_operations proc_environ_operations = {
 988         .read           = environ_read,
 989         .llseek         = generic_file_llseek,
 990 };
 991
 992 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
 993                                 size_t count, loff_t *ppos)
 994 {
 995         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 996         char buffer[PROC_NUMBUF];
 997         size_t len;
 998         int oom_adjust = OOM_DISABLE;
 999         unsigned long flags;
1000
1001         if (!task)
1002                 return -ESRCH;
1003
1004         if (lock_task_sighand(task, &flags)) {
1005                 oom_adjust = task->signal->oom_adj;
1006                 unlock_task_sighand(task, &flags);
1007         }
1008
1009         put_task_struct(task);
1010
1011         len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
1012
1013         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1014 }
1015
1016 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
1017                                 size_t count, loff_t *ppos)
1018 {
1019         struct task_struct *task;
1020         char buffer[PROC_NUMBUF];
1021         long oom_adjust;
1022         unsigned long flags;
1023         int err;
1024
1025         memset(buffer, 0, sizeof(buffer));
1026         if (count > sizeof(buffer) - 1)
1027                 count = sizeof(buffer) - 1;
1028         if (copy_from_user(buffer, buf, count)) {
1029                 err = -EFAULT;
1030                 goto out;
1031         }
1032
1033         err = strict_strtol(strstrip(buffer), 0, &oom_adjust);
1034         if (err)
1035                 goto out;
1036         if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
1037              oom_adjust != OOM_DISABLE) {
1038                 err = -EINVAL;
1039                 goto out;
1040         }
1041
1042         task = get_proc_task(file->f_path.dentry->d_inode);
1043         if (!task) {
1044                 err = -ESRCH;
1045                 goto out;
1046         }
1047
1048         task_lock(task);
1049         if (!task->mm) {
1050                 err = -EINVAL;
1051                 goto err_task_lock;
1052         }
1053
1054         if (!lock_task_sighand(task, &flags)) {
1055                 err = -ESRCH;
1056                 goto err_task_lock;
1057         }
1058
1059         if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
1060                 err = -EACCES;
1061                 goto err_sighand;
1062         }
1063
1064         if (oom_adjust != task->signal->oom_adj) {
1065                 if (oom_adjust == OOM_DISABLE)
1066                         atomic_inc(&task->mm->oom_disable_count);
1067                 if (task->signal->oom_adj == OOM_DISABLE)
1068                         atomic_dec(&task->mm->oom_disable_count);
1069         }
1070
1071         /*
1072          * Warn that /proc/pid/oom_adj is deprecated, see
1073          * Documentation/feature-removal-schedule.txt.
1074          */
1075         printk_once(KERN_WARNING "%s (%d): /proc/%d/oom_adj is deprecated, "
1076                         "please use /proc/%d/oom_score_adj instead.\n",
1077                         current->comm, task_pid_nr(current),
1078                         task_pid_nr(task), task_pid_nr(task));
1079         task->signal->oom_adj = oom_adjust;
1080         /*
1081          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1082          * value is always attainable.
1083          */
1084         if (task->signal->oom_adj == OOM_ADJUST_MAX)
1085                 task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX;
1086         else
1087                 task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
1088                                                                 -OOM_DISABLE;
1089 err_sighand:
1090         unlock_task_sighand(task, &flags);
1091 err_task_lock:
1092         task_unlock(task);
1093         put_task_struct(task);
1094 out:
1095         return err < 0 ? err : count;
1096 }
1097
1098 static const struct file_operations proc_oom_adjust_operations = {
1099         .read           = oom_adjust_read,
1100         .write          = oom_adjust_write,
1101         .llseek         = generic_file_llseek,
1102 };
1103
1104 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1105                                         size_t count, loff_t *ppos)
1106 {
1107         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1108         char buffer[PROC_NUMBUF];
1109         int oom_score_adj = OOM_SCORE_ADJ_MIN;
1110         unsigned long flags;
1111         size_t len;
1112
1113         if (!task)
1114                 return -ESRCH;
1115         if (lock_task_sighand(task, &flags)) {
1116                 oom_score_adj = task->signal->oom_score_adj;
1117                 unlock_task_sighand(task, &flags);
1118         }
1119         put_task_struct(task);
1120         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj);
1121         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1122 }
1123
1124 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1125                                         size_t count, loff_t *ppos)
1126 {
1127         struct task_struct *task;
1128         char buffer[PROC_NUMBUF];
1129         unsigned long flags;
1130         long oom_score_adj;
1131         int err;
1132
1133         memset(buffer, 0, sizeof(buffer));
1134         if (count > sizeof(buffer) - 1)
1135                 count = sizeof(buffer) - 1;
1136         if (copy_from_user(buffer, buf, count)) {
1137                 err = -EFAULT;
1138                 goto out;
1139         }
1140
1141         err = strict_strtol(strstrip(buffer), 0, &oom_score_adj);
1142         if (err)
1143                 goto out;
1144         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1145                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1146                 err = -EINVAL;
1147                 goto out;
1148         }
1149
1150         task = get_proc_task(file->f_path.dentry->d_inode);
1151         if (!task) {
1152                 err = -ESRCH;
1153                 goto out;
1154         }
1155
1156         task_lock(task);
1157         if (!task->mm) {
1158                 err = -EINVAL;
1159                 goto err_task_lock;
1160         }
1161
1162         if (!lock_task_sighand(task, &flags)) {
1163                 err = -ESRCH;
1164                 goto err_task_lock;
1165         }
1166
1167         if (oom_score_adj < task->signal->oom_score_adj &&
1168                         !capable(CAP_SYS_RESOURCE)) {
1169                 err = -EACCES;
1170                 goto err_sighand;
1171         }
1172
1173         if (oom_score_adj != task->signal->oom_score_adj) {
1174                 if (oom_score_adj == OOM_SCORE_ADJ_MIN)
1175                         atomic_inc(&task->mm->oom_disable_count);
1176                 if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1177                         atomic_dec(&task->mm->oom_disable_count);
1178         }
1179         task->signal->oom_score_adj = oom_score_adj;
1180         /*
1181          * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
1182          * always attainable.
1183          */
1184         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1185                 task->signal->oom_adj = OOM_DISABLE;
1186         else
1187                 task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
1188                                                         OOM_SCORE_ADJ_MAX;
1189 err_sighand:
1190         unlock_task_sighand(task, &flags);
1191 err_task_lock:
1192         task_unlock(task);
1193         put_task_struct(task);
1194 out:
1195         return err < 0 ? err : count;
1196 }
1197
1198 static const struct file_operations proc_oom_score_adj_operations = {
1199         .read           = oom_score_adj_read,
1200         .write          = oom_score_adj_write,
1201         .llseek         = default_llseek,
1202 };
1203
1204 #ifdef CONFIG_AUDITSYSCALL
1205 #define TMPBUFLEN 21
1206 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1207                                   size_t count, loff_t *ppos)
1208 {
1209         struct inode * inode = file->f_path.dentry->d_inode;
1210         struct task_struct *task = get_proc_task(inode);
1211         ssize_t length;
1212         char tmpbuf[TMPBUFLEN];
1213
1214         if (!task)
1215                 return -ESRCH;
1216         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1217                                 audit_get_loginuid(task));
1218         put_task_struct(task);
1219         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1220 }
1221
1222 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1223                                    size_t count, loff_t *ppos)
1224 {
1225         struct inode * inode = file->f_path.dentry->d_inode;
1226         char *page, *tmp;
1227         ssize_t length;
1228         uid_t loginuid;
1229
1230         if (!capable(CAP_AUDIT_CONTROL))
1231                 return -EPERM;
1232
1233         rcu_read_lock();
1234         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1235                 rcu_read_unlock();
1236                 return -EPERM;
1237         }
1238         rcu_read_unlock();
1239
1240         if (count >= PAGE_SIZE)
1241                 count = PAGE_SIZE - 1;
1242
1243         if (*ppos != 0) {
1244                 /* No partial writes. */
1245                 return -EINVAL;
1246         }
1247         page = (char*)__get_free_page(GFP_TEMPORARY);
1248         if (!page)
1249                 return -ENOMEM;
1250         length = -EFAULT;
1251         if (copy_from_user(page, buf, count))
1252                 goto out_free_page;
1253
1254         page[count] = '\0';
1255         loginuid = simple_strtoul(page, &tmp, 10);
1256         if (tmp == page) {
1257                 length = -EINVAL;
1258                 goto out_free_page;
1259
1260         }
1261         length = audit_set_loginuid(current, loginuid);
1262         if (likely(length == 0))
1263                 length = count;
1264
1265 out_free_page:
1266         free_page((unsigned long) page);
1267         return length;
1268 }
1269
1270 static const struct file_operations proc_loginuid_operations = {
1271         .read           = proc_loginuid_read,
1272         .write          = proc_loginuid_write,
1273         .llseek         = generic_file_llseek,
1274 };
1275
1276 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1277                                   size_t count, loff_t *ppos)
1278 {
1279         struct inode * inode = file->f_path.dentry->d_inode;
1280         struct task_struct *task = get_proc_task(inode);
1281         ssize_t length;
1282         char tmpbuf[TMPBUFLEN];
1283
1284         if (!task)
1285                 return -ESRCH;
1286         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1287                                 audit_get_sessionid(task));
1288         put_task_struct(task);
1289         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1290 }
1291
1292 static const struct file_operations proc_sessionid_operations = {
1293         .read           = proc_sessionid_read,
1294         .llseek         = generic_file_llseek,
1295 };
1296 #endif
1297
1298 #ifdef CONFIG_FAULT_INJECTION
1299 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1300                                       size_t count, loff_t *ppos)
1301 {
1302         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1303         char buffer[PROC_NUMBUF];
1304         size_t len;
1305         int make_it_fail;
1306
1307         if (!task)
1308                 return -ESRCH;
1309         make_it_fail = task->make_it_fail;
1310         put_task_struct(task);
1311
1312         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1313
1314         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1315 }
1316
1317 static ssize_t proc_fault_inject_write(struct file * file,
1318                         const char __user * buf, size_t count, loff_t *ppos)
1319 {
1320         struct task_struct *task;
1321         char buffer[PROC_NUMBUF], *end;
1322         int make_it_fail;
1323
1324         if (!capable(CAP_SYS_RESOURCE))
1325                 return -EPERM;
1326         memset(buffer, 0, sizeof(buffer));
1327         if (count > sizeof(buffer) - 1)
1328                 count = sizeof(buffer) - 1;
1329         if (copy_from_user(buffer, buf, count))
1330                 return -EFAULT;
1331         make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
1332         if (*end)
1333                 return -EINVAL;
1334         task = get_proc_task(file->f_dentry->d_inode);
1335         if (!task)
1336                 return -ESRCH;
1337         task->make_it_fail = make_it_fail;
1338         put_task_struct(task);
1339
1340         return count;
1341 }
1342
1343 static const struct file_operations proc_fault_inject_operations = {
1344         .read           = proc_fault_inject_read,
1345         .write          = proc_fault_inject_write,
1346         .llseek         = generic_file_llseek,
1347 };
1348 #endif
1349
1350
1351 #ifdef CONFIG_SCHED_DEBUG
1352 /*
1353  * Print out various scheduling related per-task fields:
1354  */
1355 static int sched_show(struct seq_file *m, void *v)
1356 {
1357         struct inode *inode = m->private;
1358         struct task_struct *p;
1359
1360         p = get_proc_task(inode);
1361         if (!p)
1362                 return -ESRCH;
1363         proc_sched_show_task(p, m);
1364
1365         put_task_struct(p);
1366
1367         return 0;
1368 }
1369
1370 static ssize_t
1371 sched_write(struct file *file, const char __user *buf,
1372             size_t count, loff_t *offset)
1373 {
1374         struct inode *inode = file->f_path.dentry->d_inode;
1375         struct task_struct *p;
1376
1377         p = get_proc_task(inode);
1378         if (!p)
1379                 return -ESRCH;
1380         proc_sched_set_task(p);
1381
1382         put_task_struct(p);
1383
1384         return count;
1385 }
1386
1387 static int sched_open(struct inode *inode, struct file *filp)
1388 {
1389         int ret;
1390
1391         ret = single_open(filp, sched_show, NULL);
1392         if (!ret) {
1393                 struct seq_file *m = filp->private_data;
1394
1395                 m->private = inode;
1396         }
1397         return ret;
1398 }
1399
1400 static const struct file_operations proc_pid_sched_operations = {
1401         .open           = sched_open,
1402         .read           = seq_read,
1403         .write          = sched_write,
1404         .llseek         = seq_lseek,
1405         .release        = single_release,
1406 };
1407
1408 #endif
1409
1410 static ssize_t comm_write(struct file *file, const char __user *buf,
1411                                 size_t count, loff_t *offset)
1412 {
1413         struct inode *inode = file->f_path.dentry->d_inode;
1414         struct task_struct *p;
1415         char buffer[TASK_COMM_LEN];
1416
1417         memset(buffer, 0, sizeof(buffer));
1418         if (count > sizeof(buffer) - 1)
1419                 count = sizeof(buffer) - 1;
1420         if (copy_from_user(buffer, buf, count))
1421                 return -EFAULT;
1422
1423         p = get_proc_task(inode);
1424         if (!p)
1425                 return -ESRCH;
1426
1427         if (same_thread_group(current, p))
1428                 set_task_comm(p, buffer);
1429         else
1430                 count = -EINVAL;
1431
1432         put_task_struct(p);
1433
1434         return count;
1435 }
1436
1437 static int comm_show(struct seq_file *m, void *v)
1438 {
1439         struct inode *inode = m->private;
1440         struct task_struct *p;
1441
1442         p = get_proc_task(inode);
1443         if (!p)
1444                 return -ESRCH;
1445
1446         task_lock(p);
1447         seq_printf(m, "%s\n", p->comm);
1448         task_unlock(p);
1449
1450         put_task_struct(p);
1451
1452         return 0;
1453 }
1454
1455 static int comm_open(struct inode *inode, struct file *filp)
1456 {
1457         int ret;
1458
1459         ret = single_open(filp, comm_show, NULL);
1460         if (!ret) {
1461                 struct seq_file *m = filp->private_data;
1462
1463                 m->private = inode;
1464         }
1465         return ret;
1466 }
1467
1468 static const struct file_operations proc_pid_set_comm_operations = {
1469         .open           = comm_open,
1470         .read           = seq_read,
1471         .write          = comm_write,
1472         .llseek         = seq_lseek,
1473         .release        = single_release,
1474 };
1475
1476 /*
1477  * We added or removed a vma mapping the executable. The vmas are only mapped
1478  * during exec and are not mapped with the mmap system call.
1479  * Callers must hold down_write() on the mm's mmap_sem for these
1480  */
1481 void added_exe_file_vma(struct mm_struct *mm)
1482 {
1483         mm->num_exe_file_vmas++;
1484 }
1485
1486 void removed_exe_file_vma(struct mm_struct *mm)
1487 {
1488         mm->num_exe_file_vmas--;
1489         if ((mm->num_exe_file_vmas == 0) && mm->exe_file){
1490                 fput(mm->exe_file);
1491                 mm->exe_file = NULL;
1492         }
1493
1494 }
1495
1496 void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
1497 {
1498         if (new_exe_file)
1499                 get_file(new_exe_file);
1500         if (mm->exe_file)
1501                 fput(mm->exe_file);
1502         mm->exe_file = new_exe_file;
1503         mm->num_exe_file_vmas = 0;
1504 }
1505
1506 struct file *get_mm_exe_file(struct mm_struct *mm)
1507 {
1508         struct file *exe_file;
1509
1510         /* We need mmap_sem to protect against races with removal of
1511          * VM_EXECUTABLE vmas */
1512         down_read(&mm->mmap_sem);
1513         exe_file = mm->exe_file;
1514         if (exe_file)
1515                 get_file(exe_file);
1516         up_read(&mm->mmap_sem);
1517         return exe_file;
1518 }
1519
1520 void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm)
1521 {
1522         /* It's safe to write the exe_file pointer without exe_file_lock because
1523          * this is called during fork when the task is not yet in /proc */
1524         newmm->exe_file = get_mm_exe_file(oldmm);
1525 }
1526
1527 static int proc_exe_link(struct inode *inode, struct path *exe_path)
1528 {
1529         struct task_struct *task;
1530         struct mm_struct *mm;
1531         struct file *exe_file;
1532
1533         task = get_proc_task(inode);
1534         if (!task)
1535                 return -ENOENT;
1536         mm = get_task_mm(task);
1537         put_task_struct(task);
1538         if (!mm)
1539                 return -ENOENT;
1540         exe_file = get_mm_exe_file(mm);
1541         mmput(mm);
1542         if (exe_file) {
1543                 *exe_path = exe_file->f_path;
1544                 path_get(&exe_file->f_path);
1545                 fput(exe_file);
1546                 return 0;
1547         } else
1548                 return -ENOENT;
1549 }
1550
1551 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1552 {
1553         struct inode *inode = dentry->d_inode;
1554         int error = -EACCES;
1555
1556         /* We don't need a base pointer in the /proc filesystem */
1557         path_put(&nd->path);
1558
1559         /* Are we allowed to snoop on the tasks file descriptors? */
1560         if (!proc_fd_access_allowed(inode))
1561                 goto out;
1562
1563         error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1564 out:
1565         return ERR_PTR(error);
1566 }
1567
1568 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1569 {
1570         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1571         char *pathname;
1572         int len;
1573
1574         if (!tmp)
1575                 return -ENOMEM;
1576
1577         pathname = d_path(path, tmp, PAGE_SIZE);
1578         len = PTR_ERR(pathname);
1579         if (IS_ERR(pathname))
1580                 goto out;
1581         len = tmp + PAGE_SIZE - 1 - pathname;
1582
1583         if (len > buflen)
1584                 len = buflen;
1585         if (copy_to_user(buffer, pathname, len))
1586                 len = -EFAULT;
1587  out:
1588         free_page((unsigned long)tmp);
1589         return len;
1590 }
1591
1592 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1593 {
1594         int error = -EACCES;
1595         struct inode *inode = dentry->d_inode;
1596         struct path path;
1597
1598         /* Are we allowed to snoop on the tasks file descriptors? */
1599         if (!proc_fd_access_allowed(inode))
1600                 goto out;
1601
1602         error = PROC_I(inode)->op.proc_get_link(inode, &path);
1603         if (error)
1604                 goto out;
1605
1606         error = do_proc_readlink(&path, buffer, buflen);
1607         path_put(&path);
1608 out:
1609         return error;
1610 }
1611
1612 static const struct inode_operations proc_pid_link_inode_operations = {
1613         .readlink       = proc_pid_readlink,
1614         .follow_link    = proc_pid_follow_link,
1615         .setattr        = proc_setattr,
1616 };
1617
1618
1619 /* building an inode */
1620
1621 static int task_dumpable(struct task_struct *task)
1622 {
1623         int dumpable = 0;
1624         struct mm_struct *mm;
1625
1626         task_lock(task);
1627         mm = task->mm;
1628         if (mm)
1629                 dumpable = get_dumpable(mm);
1630         task_unlock(task);
1631         if(dumpable == 1)
1632                 return 1;
1633         return 0;
1634 }
1635
1636
1637 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1638 {
1639         struct inode * inode;
1640         struct proc_inode *ei;
1641         const struct cred *cred;
1642
1643         /* We need a new inode */
1644
1645         inode = new_inode(sb);
1646         if (!inode)
1647                 goto out;
1648
1649         /* Common stuff */
1650         ei = PROC_I(inode);
1651         inode->i_ino = get_next_ino();
1652         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1653         inode->i_op = &proc_def_inode_operations;
1654
1655         /*
1656          * grab the reference to task.
1657          */
1658         ei->pid = get_task_pid(task, PIDTYPE_PID);
1659         if (!ei->pid)
1660                 goto out_unlock;
1661
1662         if (task_dumpable(task)) {
1663                 rcu_read_lock();
1664                 cred = __task_cred(task);
1665                 inode->i_uid = cred->euid;
1666                 inode->i_gid = cred->egid;
1667                 rcu_read_unlock();
1668         }
1669         security_task_to_inode(task, inode);
1670
1671 out:
1672         return inode;
1673
1674 out_unlock:
1675         iput(inode);
1676         return NULL;
1677 }
1678
1679 static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1680 {
1681         struct inode *inode = dentry->d_inode;
1682         struct task_struct *task;
1683         const struct cred *cred;
1684
1685         generic_fillattr(inode, stat);
1686
1687         rcu_read_lock();
1688         stat->uid = 0;
1689         stat->gid = 0;
1690         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1691         if (task) {
1692                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1693                     task_dumpable(task)) {
1694                         cred = __task_cred(task);
1695                         stat->uid = cred->euid;
1696                         stat->gid = cred->egid;
1697                 }
1698         }
1699         rcu_read_unlock();
1700         return 0;
1701 }
1702
1703 /* dentry stuff */
1704
1705 /*
1706  *      Exceptional case: normally we are not allowed to unhash a busy
1707  * directory. In this case, however, we can do it - no aliasing problems
1708  * due to the way we treat inodes.
1709  *
1710  * Rewrite the inode's ownerships here because the owning task may have
1711  * performed a setuid(), etc.
1712  *
1713  * Before the /proc/pid/status file was created the only way to read
1714  * the effective uid of a /process was to stat /proc/pid.  Reading
1715  * /proc/pid/status is slow enough that procps and other packages
1716  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1717  * made this apply to all per process world readable and executable
1718  * directories.
1719  */
1720 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1721 {
1722         struct inode *inode;
1723         struct task_struct *task;
1724         const struct cred *cred;
1725
1726         if (nd && nd->flags & LOOKUP_RCU)
1727                 return -ECHILD;
1728
1729         inode = dentry->d_inode;
1730         task = get_proc_task(inode);
1731
1732         if (task) {
1733                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1734                     task_dumpable(task)) {
1735                         rcu_read_lock();
1736                         cred = __task_cred(task);
1737                         inode->i_uid = cred->euid;
1738                         inode->i_gid = cred->egid;
1739                         rcu_read_unlock();
1740                 } else {
1741                         inode->i_uid = 0;
1742                         inode->i_gid = 0;
1743                 }
1744                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1745                 security_task_to_inode(task, inode);
1746                 put_task_struct(task);
1747                 return 1;
1748         }
1749         d_drop(dentry);
1750         return 0;
1751 }
1752
1753 static int pid_delete_dentry(const struct dentry * dentry)
1754 {
1755         /* Is the task we represent dead?
1756          * If so, then don't put the dentry on the lru list,
1757          * kill it immediately.
1758          */
1759         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1760 }
1761
1762 static const struct dentry_operations pid_dentry_operations =
1763 {
1764         .d_revalidate   = pid_revalidate,
1765         .d_delete       = pid_delete_dentry,
1766 };
1767
1768 /* Lookups */
1769
1770 typedef struct dentry *instantiate_t(struct inode *, struct dentry *,
1771                                 struct task_struct *, const void *);
1772
1773 /*
1774  * Fill a directory entry.
1775  *
1776  * If possible create the dcache entry and derive our inode number and
1777  * file type from dcache entry.
1778  *
1779  * Since all of the proc inode numbers are dynamically generated, the inode
1780  * numbers do not exist until the inode is cache.  This means creating the
1781  * the dcache entry in readdir is necessary to keep the inode numbers
1782  * reported by readdir in sync with the inode numbers reported
1783  * by stat.
1784  */
1785 static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1786         char *name, int len,
1787         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1788 {
1789         struct dentry *child, *dir = filp->f_path.dentry;
1790         struct inode *inode;
1791         struct qstr qname;
1792         ino_t ino = 0;
1793         unsigned type = DT_UNKNOWN;
1794
1795         qname.name = name;
1796         qname.len  = len;
1797         qname.hash = full_name_hash(name, len);
1798
1799         child = d_lookup(dir, &qname);
1800         if (!child) {
1801                 struct dentry *new;
1802                 new = d_alloc(dir, &qname);
1803                 if (new) {
1804                         child = instantiate(dir->d_inode, new, task, ptr);
1805                         if (child)
1806                                 dput(new);
1807                         else
1808                                 child = new;
1809                 }
1810         }
1811         if (!child || IS_ERR(child) || !child->d_inode)
1812                 goto end_instantiate;
1813         inode = child->d_inode;
1814         if (inode) {
1815                 ino = inode->i_ino;
1816                 type = inode->i_mode >> 12;
1817         }
1818         dput(child);
1819 end_instantiate:
1820         if (!ino)
1821                 ino = find_inode_number(dir, &qname);
1822         if (!ino)
1823                 ino = 1;
1824         return filldir(dirent, name, len, filp->f_pos, ino, type);
1825 }
1826
1827 static unsigned name_to_int(struct dentry *dentry)
1828 {
1829         const char *name = dentry->d_name.name;
1830         int len = dentry->d_name.len;
1831         unsigned n = 0;
1832
1833         if (len > 1 && *name == '0')
1834                 goto out;
1835         while (len-- > 0) {
1836                 unsigned c = *name++ - '0';
1837                 if (c > 9)
1838                         goto out;
1839                 if (n >= (~0U-9)/10)
1840                         goto out;
1841                 n *= 10;
1842                 n += c;
1843         }
1844         return n;
1845 out:
1846         return ~0U;
1847 }
1848
1849 #define PROC_FDINFO_MAX 64
1850
1851 static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1852 {
1853         struct task_struct *task = get_proc_task(inode);
1854         struct files_struct *files = NULL;
1855         struct file *file;
1856         int fd = proc_fd(inode);
1857
1858         if (task) {
1859                 files = get_files_struct(task);
1860                 put_task_struct(task);
1861         }
1862         if (files) {
1863                 /*
1864                  * We are not taking a ref to the file structure, so we must
1865                  * hold ->file_lock.
1866                  */
1867                 spin_lock(&files->file_lock);
1868                 file = fcheck_files(files, fd);
1869                 if (file) {
1870                         if (path) {
1871                                 *path = file->f_path;
1872                                 path_get(&file->f_path);
1873                         }
1874                         if (info)
1875                                 snprintf(info, PROC_FDINFO_MAX,
1876                                          "pos:\t%lli\n"
1877                                          "flags:\t0%o\n",
1878                                          (long long) file->f_pos,
1879                                          file->f_flags);
1880                         spin_unlock(&files->file_lock);
1881                         put_files_struct(files);
1882                         return 0;
1883                 }
1884                 spin_unlock(&files->file_lock);
1885                 put_files_struct(files);
1886         }
1887         return -ENOENT;
1888 }
1889
1890 static int proc_fd_link(struct inode *inode, struct path *path)
1891 {
1892         return proc_fd_info(inode, path, NULL);
1893 }
1894
1895 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1896 {
1897         struct inode *inode;
1898         struct task_struct *task;
1899         int fd;
1900         struct files_struct *files;
1901         const struct cred *cred;
1902
1903         if (nd && nd->flags & LOOKUP_RCU)
1904                 return -ECHILD;
1905
1906         inode = dentry->d_inode;
1907         task = get_proc_task(inode);
1908         fd = proc_fd(inode);
1909
1910         if (task) {
1911                 files = get_files_struct(task);
1912                 if (files) {
1913                         rcu_read_lock();
1914                         if (fcheck_files(files, fd)) {
1915                                 rcu_read_unlock();
1916                                 put_files_struct(files);
1917                                 if (task_dumpable(task)) {
1918                                         rcu_read_lock();
1919                                         cred = __task_cred(task);
1920                                         inode->i_uid = cred->euid;
1921                                         inode->i_gid = cred->egid;
1922                                         rcu_read_unlock();
1923                                 } else {
1924                                         inode->i_uid = 0;
1925                                         inode->i_gid = 0;
1926                                 }
1927                                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1928                                 security_task_to_inode(task, inode);
1929                                 put_task_struct(task);
1930                                 return 1;
1931                         }
1932                         rcu_read_unlock();
1933                         put_files_struct(files);
1934                 }
1935                 put_task_struct(task);
1936         }
1937         d_drop(dentry);
1938         return 0;
1939 }
1940
1941 static const struct dentry_operations tid_fd_dentry_operations =
1942 {
1943         .d_revalidate   = tid_fd_revalidate,
1944         .d_delete       = pid_delete_dentry,
1945 };
1946
1947 static struct dentry *proc_fd_instantiate(struct inode *dir,
1948         struct dentry *dentry, struct task_struct *task, const void *ptr)
1949 {
1950         unsigned fd = *(const unsigned *)ptr;
1951         struct file *file;
1952         struct files_struct *files;
1953         struct inode *inode;
1954         struct proc_inode *ei;
1955         struct dentry *error = ERR_PTR(-ENOENT);
1956
1957         inode = proc_pid_make_inode(dir->i_sb, task);
1958         if (!inode)
1959                 goto out;
1960         ei = PROC_I(inode);
1961         ei->fd = fd;
1962         files = get_files_struct(task);
1963         if (!files)
1964                 goto out_iput;
1965         inode->i_mode = S_IFLNK;
1966
1967         /*
1968          * We are not taking a ref to the file structure, so we must
1969          * hold ->file_lock.
1970          */
1971         spin_lock(&files->file_lock);
1972         file = fcheck_files(files, fd);
1973         if (!file)
1974                 goto out_unlock;
1975         if (file->f_mode & FMODE_READ)
1976                 inode->i_mode |= S_IRUSR | S_IXUSR;
1977         if (file->f_mode & FMODE_WRITE)
1978                 inode->i_mode |= S_IWUSR | S_IXUSR;
1979         spin_unlock(&files->file_lock);
1980         put_files_struct(files);
1981
1982         inode->i_op = &proc_pid_link_inode_operations;
1983         inode->i_size = 64;
1984         ei->op.proc_get_link = proc_fd_link;
1985         d_set_d_op(dentry, &tid_fd_dentry_operations);
1986         d_add(dentry, inode);
1987         /* Close the race of the process dying before we return the dentry */
1988         if (tid_fd_revalidate(dentry, NULL))
1989                 error = NULL;
1990
1991  out:
1992         return error;
1993 out_unlock:
1994         spin_unlock(&files->file_lock);
1995         put_files_struct(files);
1996 out_iput:
1997         iput(inode);
1998         goto out;
1999 }
2000
2001 static struct dentry *proc_lookupfd_common(struct inode *dir,
2002                                            struct dentry *dentry,
2003                                            instantiate_t instantiate)
2004 {
2005         struct task_struct *task = get_proc_task(dir);
2006         unsigned fd = name_to_int(dentry);
2007         struct dentry *result = ERR_PTR(-ENOENT);
2008
2009         if (!task)
2010                 goto out_no_task;
2011         if (fd == ~0U)
2012                 goto out;
2013
2014         result = instantiate(dir, dentry, task, &fd);
2015 out:
2016         put_task_struct(task);
2017 out_no_task:
2018         return result;
2019 }
2020
2021 static int proc_readfd_common(struct file * filp, void * dirent,
2022                               filldir_t filldir, instantiate_t instantiate)
2023 {
2024         struct dentry *dentry = filp->f_path.dentry;
2025         struct inode *inode = dentry->d_inode;
2026         struct task_struct *p = get_proc_task(inode);
2027         unsigned int fd, ino;
2028         int retval;
2029         struct files_struct * files;
2030
2031         retval = -ENOENT;
2032         if (!p)
2033                 goto out_no_task;
2034         retval = 0;
2035
2036         fd = filp->f_pos;
2037         switch (fd) {
2038                 case 0:
2039                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
2040                                 goto out;
2041                         filp->f_pos++;
2042                 case 1:
2043                         ino = parent_ino(dentry);
2044                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
2045                                 goto out;
2046                         filp->f_pos++;
2047                 default:
2048                         files = get_files_struct(p);
2049                         if (!files)
2050                                 goto out;
2051                         rcu_read_lock();
2052                         for (fd = filp->f_pos-2;
2053                              fd < files_fdtable(files)->max_fds;
2054                              fd++, filp->f_pos++) {
2055                                 char name[PROC_NUMBUF];
2056                                 int len;
2057
2058                                 if (!fcheck_files(files, fd))
2059                                         continue;
2060                                 rcu_read_unlock();
2061
2062                                 len = snprintf(name, sizeof(name), "%d", fd);
2063                                 if (proc_fill_cache(filp, dirent, filldir,
2064                                                     name, len, instantiate,
2065                                                     p, &fd) < 0) {
2066                                         rcu_read_lock();
2067                                         break;
2068                                 }
2069                                 rcu_read_lock();
2070                         }
2071                         rcu_read_unlock();
2072                         put_files_struct(files);
2073         }
2074 out:
2075         put_task_struct(p);
2076 out_no_task:
2077         return retval;
2078 }
2079
2080 static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
2081                                     struct nameidata *nd)
2082 {
2083         return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
2084 }
2085
2086 static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
2087 {
2088         return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
2089 }
2090
2091 static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
2092                                       size_t len, loff_t *ppos)
2093 {
2094         char tmp[PROC_FDINFO_MAX];
2095         int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
2096         if (!err)
2097                 err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
2098         return err;
2099 }
2100
2101 static const struct file_operations proc_fdinfo_file_operations = {
2102         .open           = nonseekable_open,
2103         .read           = proc_fdinfo_read,
2104         .llseek         = no_llseek,
2105 };
2106
2107 static const struct file_operations proc_fd_operations = {
2108         .read           = generic_read_dir,
2109         .readdir        = proc_readfd,
2110         .llseek         = default_llseek,
2111 };
2112
2113 /*
2114  * /proc/pid/fd needs a special permission handler so that a process can still
2115  * access /proc/self/fd after it has executed a setuid().
2116  */
2117 static int proc_fd_permission(struct inode *inode, int mask)
2118 {
2119         int rv;
2120
2121         rv = generic_permission(inode, mask, NULL);
2122         if (rv == 0)
2123                 return 0;
2124         if (task_pid(current) == proc_pid(inode))
2125                 rv = 0;
2126         return rv;
2127 }
2128
2129 /*
2130  * proc directories can do almost nothing..
2131  */
2132 static const struct inode_operations proc_fd_inode_operations = {
2133         .lookup         = proc_lookupfd,
2134         .permission     = proc_fd_permission,
2135         .setattr        = proc_setattr,
2136 };
2137
2138 static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
2139         struct dentry *dentry, struct task_struct *task, const void *ptr)
2140 {
2141         unsigned fd = *(unsigned *)ptr;
2142         struct inode *inode;
2143         struct proc_inode *ei;
2144         struct dentry *error = ERR_PTR(-ENOENT);
2145
2146         inode = proc_pid_make_inode(dir->i_sb, task);
2147         if (!inode)
2148                 goto out;
2149         ei = PROC_I(inode);
2150         ei->fd = fd;
2151         inode->i_mode = S_IFREG | S_IRUSR;
2152         inode->i_fop = &proc_fdinfo_file_operations;
2153         d_set_d_op(dentry, &tid_fd_dentry_operations);
2154         d_add(dentry, inode);
2155         /* Close the race of the process dying before we return the dentry */
2156         if (tid_fd_revalidate(dentry, NULL))
2157                 error = NULL;
2158
2159  out:
2160         return error;
2161 }
2162
2163 static struct dentry *proc_lookupfdinfo(struct inode *dir,
2164                                         struct dentry *dentry,
2165                                         struct nameidata *nd)
2166 {
2167         return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
2168 }
2169
2170 static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
2171 {
2172         return proc_readfd_common(filp, dirent, filldir,
2173                                   proc_fdinfo_instantiate);
2174 }
2175
2176 static const struct file_operations proc_fdinfo_operations = {
2177         .read           = generic_read_dir,
2178         .readdir        = proc_readfdinfo,
2179         .llseek         = default_llseek,
2180 };
2181
2182 /*
2183  * proc directories can do almost nothing..
2184  */
2185 static const struct inode_operations proc_fdinfo_inode_operations = {
2186         .lookup         = proc_lookupfdinfo,
2187         .setattr        = proc_setattr,
2188 };
2189
2190
2191 static struct dentry *proc_pident_instantiate(struct inode *dir,
2192         struct dentry *dentry, struct task_struct *task, const void *ptr)
2193 {
2194         const struct pid_entry *p = ptr;
2195         struct inode *inode;
2196         struct proc_inode *ei;
2197         struct dentry *error = ERR_PTR(-ENOENT);
2198
2199         inode = proc_pid_make_inode(dir->i_sb, task);
2200         if (!inode)
2201                 goto out;
2202
2203         ei = PROC_I(inode);
2204         inode->i_mode = p->mode;
2205         if (S_ISDIR(inode->i_mode))
2206                 inode->i_nlink = 2;     /* Use getattr to fix if necessary */
2207         if (p->iop)
2208                 inode->i_op = p->iop;
2209         if (p->fop)
2210                 inode->i_fop = p->fop;
2211         ei->op = p->op;
2212         d_set_d_op(dentry, &pid_dentry_operations);
2213         d_add(dentry, inode);
2214         /* Close the race of the process dying before we return the dentry */
2215         if (pid_revalidate(dentry, NULL))
2216                 error = NULL;
2217 out:
2218         return error;
2219 }
2220
2221 static struct dentry *proc_pident_lookup(struct inode *dir,
2222                                          struct dentry *dentry,
2223                                          const struct pid_entry *ents,
2224                                          unsigned int nents)
2225 {
2226         struct dentry *error;
2227         struct task_struct *task = get_proc_task(dir);
2228         const struct pid_entry *p, *last;
2229
2230         error = ERR_PTR(-ENOENT);
2231
2232         if (!task)
2233                 goto out_no_task;
2234
2235         /*
2236          * Yes, it does not scale. And it should not. Don't add
2237          * new entries into /proc/<tgid>/ without very good reasons.
2238          */
2239         last = &ents[nents - 1];
2240         for (p = ents; p <= last; p++) {
2241                 if (p->len != dentry->d_name.len)
2242                         continue;
2243                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2244                         break;
2245         }
2246         if (p > last)
2247                 goto out;
2248
2249         error = proc_pident_instantiate(dir, dentry, task, p);
2250 out:
2251         put_task_struct(task);
2252 out_no_task:
2253         return error;
2254 }
2255
2256 static int proc_pident_fill_cache(struct file *filp, void *dirent,
2257         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2258 {
2259         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2260                                 proc_pident_instantiate, task, p);
2261 }
2262
2263 static int proc_pident_readdir(struct file *filp,
2264                 void *dirent, filldir_t filldir,
2265                 const struct pid_entry *ents, unsigned int nents)
2266 {
2267         int i;
2268         struct dentry *dentry = filp->f_path.dentry;
2269         struct inode *inode = dentry->d_inode;
2270         struct task_struct *task = get_proc_task(inode);
2271         const struct pid_entry *p, *last;
2272         ino_t ino;
2273         int ret;
2274
2275         ret = -ENOENT;
2276         if (!task)
2277                 goto out_no_task;
2278
2279         ret = 0;
2280         i = filp->f_pos;
2281         switch (i) {
2282         case 0:
2283                 ino = inode->i_ino;
2284                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2285                         goto out;
2286                 i++;
2287                 filp->f_pos++;
2288                 /* fall through */
2289         case 1:
2290                 ino = parent_ino(dentry);
2291                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2292                         goto out;
2293                 i++;
2294                 filp->f_pos++;
2295                 /* fall through */
2296         default:
2297                 i -= 2;
2298                 if (i >= nents) {
2299                         ret = 1;
2300                         goto out;
2301                 }
2302                 p = ents + i;
2303                 last = &ents[nents - 1];
2304                 while (p <= last) {
2305                         if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2306                                 goto out;
2307                         filp->f_pos++;
2308                         p++;
2309                 }
2310         }
2311
2312         ret = 1;
2313 out:
2314         put_task_struct(task);
2315 out_no_task:
2316         return ret;
2317 }
2318
2319 #ifdef CONFIG_SECURITY
2320 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2321                                   size_t count, loff_t *ppos)
2322 {
2323         struct inode * inode = file->f_path.dentry->d_inode;
2324         char *p = NULL;
2325         ssize_t length;
2326         struct task_struct *task = get_proc_task(inode);
2327
2328         if (!task)
2329                 return -ESRCH;
2330
2331         length = security_getprocattr(task,
2332                                       (char*)file->f_path.dentry->d_name.name,
2333                                       &p);
2334         put_task_struct(task);
2335         if (length > 0)
2336                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2337         kfree(p);
2338         return length;
2339 }
2340
2341 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2342                                    size_t count, loff_t *ppos)
2343 {
2344         struct inode * inode = file->f_path.dentry->d_inode;
2345         char *page;
2346         ssize_t length;
2347         struct task_struct *task = get_proc_task(inode);
2348
2349         length = -ESRCH;
2350         if (!task)
2351                 goto out_no_task;
2352         if (count > PAGE_SIZE)
2353                 count = PAGE_SIZE;
2354
2355         /* No partial writes. */
2356         length = -EINVAL;
2357         if (*ppos != 0)
2358                 goto out;
2359
2360         length = -ENOMEM;
2361         page = (char*)__get_free_page(GFP_TEMPORARY);
2362         if (!page)
2363                 goto out;
2364
2365         length = -EFAULT;
2366         if (copy_from_user(page, buf, count))
2367                 goto out_free;
2368
2369         /* Guard against adverse ptrace interaction */
2370         length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2371         if (length < 0)
2372                 goto out_free;
2373
2374         length = security_setprocattr(task,
2375                                       (char*)file->f_path.dentry->d_name.name,
2376                                       (void*)page, count);
2377         mutex_unlock(&task->signal->cred_guard_mutex);
2378 out_free:
2379         free_page((unsigned long) page);
2380 out:
2381         put_task_struct(task);
2382 out_no_task:
2383         return length;
2384 }
2385
2386 static const struct file_operations proc_pid_attr_operations = {
2387         .read           = proc_pid_attr_read,
2388         .write          = proc_pid_attr_write,
2389         .llseek         = generic_file_llseek,
2390 };
2391
2392 static const struct pid_entry attr_dir_stuff[] = {
2393         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2394         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2395         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2396         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2397         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2398         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2399 };
2400
2401 static int proc_attr_dir_readdir(struct file * filp,
2402                              void * dirent, filldir_t filldir)
2403 {
2404         return proc_pident_readdir(filp,dirent,filldir,
2405                                    attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2406 }
2407
2408 static const struct file_operations proc_attr_dir_operations = {
2409         .read           = generic_read_dir,
2410         .readdir        = proc_attr_dir_readdir,
2411         .llseek         = default_llseek,
2412 };
2413
2414 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2415                                 struct dentry *dentry, struct nameidata *nd)
2416 {
2417         return proc_pident_lookup(dir, dentry,
2418                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2419 }
2420
2421 static const struct inode_operations proc_attr_dir_inode_operations = {
2422         .lookup         = proc_attr_dir_lookup,
2423         .getattr        = pid_getattr,
2424         .setattr        = proc_setattr,
2425 };
2426
2427 #endif
2428
2429 #ifdef CONFIG_ELF_CORE
2430 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2431                                          size_t count, loff_t *ppos)
2432 {
2433         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2434         struct mm_struct *mm;
2435         char buffer[PROC_NUMBUF];
2436         size_t len;
2437         int ret;
2438
2439         if (!task)
2440                 return -ESRCH;
2441
2442         ret = 0;
2443         mm = get_task_mm(task);
2444         if (mm) {
2445                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2446                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2447                                 MMF_DUMP_FILTER_SHIFT));
2448                 mmput(mm);
2449                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2450         }
2451
2452         put_task_struct(task);
2453
2454         return ret;
2455 }
2456
2457 static ssize_t proc_coredump_filter_write(struct file *file,
2458                                           const char __user *buf,
2459                                           size_t count,
2460                                           loff_t *ppos)
2461 {
2462         struct task_struct *task;
2463         struct mm_struct *mm;
2464         char buffer[PROC_NUMBUF], *end;
2465         unsigned int val;
2466         int ret;
2467         int i;
2468         unsigned long mask;
2469
2470         ret = -EFAULT;
2471         memset(buffer, 0, sizeof(buffer));
2472         if (count > sizeof(buffer) - 1)
2473                 count = sizeof(buffer) - 1;
2474         if (copy_from_user(buffer, buf, count))
2475                 goto out_no_task;
2476
2477         ret = -EINVAL;
2478         val = (unsigned int)simple_strtoul(buffer, &end, 0);
2479         if (*end == '\n')
2480                 end++;
2481         if (end - buffer == 0)
2482                 goto out_no_task;
2483
2484         ret = -ESRCH;
2485         task = get_proc_task(file->f_dentry->d_inode);
2486         if (!task)
2487                 goto out_no_task;
2488
2489         ret = end - buffer;
2490         mm = get_task_mm(task);
2491         if (!mm)
2492                 goto out_no_mm;
2493
2494         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2495                 if (val & mask)
2496                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2497                 else
2498                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2499         }
2500
2501         mmput(mm);
2502  out_no_mm:
2503         put_task_struct(task);
2504  out_no_task:
2505         return ret;
2506 }
2507
2508 static const struct file_operations proc_coredump_filter_operations = {
2509         .read           = proc_coredump_filter_read,
2510         .write          = proc_coredump_filter_write,
2511         .llseek         = generic_file_llseek,
2512 };
2513 #endif
2514
2515 /*
2516  * /proc/self:
2517  */
2518 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2519                               int buflen)
2520 {
2521         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2522         pid_t tgid = task_tgid_nr_ns(current, ns);
2523         char tmp[PROC_NUMBUF];
2524         if (!tgid)
2525                 return -ENOENT;
2526         sprintf(tmp, "%d", tgid);
2527         return vfs_readlink(dentry,buffer,buflen,tmp);
2528 }
2529
2530 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2531 {
2532         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2533         pid_t tgid = task_tgid_nr_ns(current, ns);
2534         char *name = ERR_PTR(-ENOENT);
2535         if (tgid) {
2536                 name = __getname();
2537                 if (!name)
2538                         name = ERR_PTR(-ENOMEM);
2539                 else
2540                         sprintf(name, "%d", tgid);
2541         }
2542         nd_set_link(nd, name);
2543         return NULL;
2544 }
2545
2546 static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
2547                                 void *cookie)
2548 {
2549         char *s = nd_get_link(nd);
2550         if (!IS_ERR(s))
2551                 __putname(s);
2552 }
2553
2554 static const struct inode_operations proc_self_inode_operations = {
2555         .readlink       = proc_self_readlink,
2556         .follow_link    = proc_self_follow_link,
2557         .put_link       = proc_self_put_link,
2558 };
2559
2560 /*
2561  * proc base
2562  *
2563  * These are the directory entries in the root directory of /proc
2564  * that properly belong to the /proc filesystem, as they describe
2565  * describe something that is process related.
2566  */
2567 static const struct pid_entry proc_base_stuff[] = {
2568         NOD("self", S_IFLNK|S_IRWXUGO,
2569                 &proc_self_inode_operations, NULL, {}),
2570 };
2571
2572 /*
2573  *      Exceptional case: normally we are not allowed to unhash a busy
2574  * directory. In this case, however, we can do it - no aliasing problems
2575  * due to the way we treat inodes.
2576  */
2577 static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd)
2578 {
2579         struct inode *inode;
2580         struct task_struct *task;
2581
2582         if (nd->flags & LOOKUP_RCU)
2583                 return -ECHILD;
2584
2585         inode = dentry->d_inode;
2586         task = get_proc_task(inode);
2587         if (task) {
2588                 put_task_struct(task);
2589                 return 1;
2590         }
2591         d_drop(dentry);
2592         return 0;
2593 }
2594
2595 static const struct dentry_operations proc_base_dentry_operations =
2596 {
2597         .d_revalidate   = proc_base_revalidate,
2598         .d_delete       = pid_delete_dentry,
2599 };
2600
2601 static struct dentry *proc_base_instantiate(struct inode *dir,
2602         struct dentry *dentry, struct task_struct *task, const void *ptr)
2603 {
2604         const struct pid_entry *p = ptr;
2605         struct inode *inode;
2606         struct proc_inode *ei;
2607         struct dentry *error;
2608
2609         /* Allocate the inode */
2610         error = ERR_PTR(-ENOMEM);
2611         inode = new_inode(dir->i_sb);
2612         if (!inode)
2613                 goto out;
2614
2615         /* Initialize the inode */
2616         ei = PROC_I(inode);
2617         inode->i_ino = get_next_ino();
2618         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2619
2620         /*
2621          * grab the reference to the task.
2622          */
2623         ei->pid = get_task_pid(task, PIDTYPE_PID);
2624         if (!ei->pid)
2625                 goto out_iput;
2626
2627         inode->i_mode = p->mode;
2628         if (S_ISDIR(inode->i_mode))
2629                 inode->i_nlink = 2;
2630         if (S_ISLNK(inode->i_mode))
2631                 inode->i_size = 64;
2632         if (p->iop)
2633                 inode->i_op = p->iop;
2634         if (p->fop)
2635                 inode->i_fop = p->fop;
2636         ei->op = p->op;
2637         d_set_d_op(dentry, &proc_base_dentry_operations);
2638         d_add(dentry, inode);
2639         error = NULL;
2640 out:
2641         return error;
2642 out_iput:
2643         iput(inode);
2644         goto out;
2645 }
2646
2647 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2648 {
2649         struct dentry *error;
2650         struct task_struct *task = get_proc_task(dir);
2651         const struct pid_entry *p, *last;
2652
2653         error = ERR_PTR(-ENOENT);
2654
2655         if (!task)
2656                 goto out_no_task;
2657
2658         /* Lookup the directory entry */
2659         last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2660         for (p = proc_base_stuff; p <= last; p++) {
2661                 if (p->len != dentry->d_name.len)
2662                         continue;
2663                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2664                         break;
2665         }
2666         if (p > last)
2667                 goto out;
2668
2669         error = proc_base_instantiate(dir, dentry, task, p);
2670
2671 out:
2672         put_task_struct(task);
2673 out_no_task:
2674         return error;
2675 }
2676
2677 static int proc_base_fill_cache(struct file *filp, void *dirent,
2678         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2679 {
2680         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2681                                 proc_base_instantiate, task, p);
2682 }
2683
2684 #ifdef CONFIG_TASK_IO_ACCOUNTING
2685 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2686 {
2687         struct task_io_accounting acct = task->ioac;
2688         unsigned long flags;
2689
2690         if (whole && lock_task_sighand(task, &flags)) {
2691                 struct task_struct *t = task;
2692
2693                 task_io_accounting_add(&acct, &task->signal->ioac);
2694                 while_each_thread(task, t)
2695                         task_io_accounting_add(&acct, &t->ioac);
2696
2697                 unlock_task_sighand(task, &flags);
2698         }
2699         return sprintf(buffer,
2700                         "rchar: %llu\n"
2701                         "wchar: %llu\n"
2702                         "syscr: %llu\n"
2703                         "syscw: %llu\n"
2704                         "read_bytes: %llu\n"
2705                         "write_bytes: %llu\n"
2706                         "cancelled_write_bytes: %llu\n",
2707                         (unsigned long long)acct.rchar,
2708                         (unsigned long long)acct.wchar,
2709                         (unsigned long long)acct.syscr,
2710                         (unsigned long long)acct.syscw,
2711                         (unsigned long long)acct.read_bytes,
2712                         (unsigned long long)acct.write_bytes,
2713                         (unsigned long long)acct.cancelled_write_bytes);
2714 }
2715
2716 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2717 {
2718         return do_io_accounting(task, buffer, 0);
2719 }
2720
2721 static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2722 {
2723         return do_io_accounting(task, buffer, 1);
2724 }
2725 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2726
2727 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2728                                 struct pid *pid, struct task_struct *task)
2729 {
2730         seq_printf(m, "%08x\n", task->personality);
2731         return 0;
2732 }
2733
2734 /*
2735  * Thread groups
2736  */
2737 static const struct file_operations proc_task_operations;
2738 static const struct inode_operations proc_task_inode_operations;
2739
2740 static const struct pid_entry tgid_base_stuff[] = {
2741         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2742         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2743         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2744 #ifdef CONFIG_NET
2745         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2746 #endif
2747         REG("environ",    S_IRUSR, proc_environ_operations),
2748         INF("auxv",       S_IRUSR, proc_pid_auxv),
2749         ONE("status",     S_IRUGO, proc_pid_status),
2750         ONE("personality", S_IRUSR, proc_pid_personality),
2751         INF("limits",     S_IRUGO, proc_pid_limits),
2752 #ifdef CONFIG_SCHED_DEBUG
2753         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2754 #endif
2755         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2756 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2757         INF("syscall",    S_IRUSR, proc_pid_syscall),
2758 #endif
2759         INF("cmdline",    S_IRUGO, proc_pid_cmdline),
2760         ONE("stat",       S_IRUGO, proc_tgid_stat),
2761         ONE("statm",      S_IRUGO, proc_pid_statm),
2762         REG("maps",       S_IRUGO, proc_maps_operations),
2763 #ifdef CONFIG_NUMA
2764         REG("numa_maps",  S_IRUGO, proc_numa_maps_operations),
2765 #endif
2766         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2767         LNK("cwd",        proc_cwd_link),
2768         LNK("root",       proc_root_link),
2769         LNK("exe",        proc_exe_link),
2770         REG("mounts",     S_IRUGO, proc_mounts_operations),
2771         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2772         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2773 #ifdef CONFIG_PROC_PAGE_MONITOR
2774         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2775         REG("smaps",      S_IRUGO, proc_smaps_operations),
2776         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2777 #endif
2778 #ifdef CONFIG_SECURITY
2779         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2780 #endif
2781 #ifdef CONFIG_KALLSYMS
2782         INF("wchan",      S_IRUGO, proc_pid_wchan),
2783 #endif
2784 #ifdef CONFIG_STACKTRACE
2785         ONE("stack",      S_IRUSR, proc_pid_stack),
2786 #endif
2787 #ifdef CONFIG_SCHEDSTATS
2788         INF("schedstat",  S_IRUGO, proc_pid_schedstat),
2789 #endif
2790 #ifdef CONFIG_LATENCYTOP
2791         REG("latency",  S_IRUGO, proc_lstats_operations),
2792 #endif
2793 #ifdef CONFIG_PROC_PID_CPUSET
2794         REG("cpuset",     S_IRUGO, proc_cpuset_operations),
2795 #endif
2796 #ifdef CONFIG_CGROUPS
2797         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2798 #endif
2799         INF("oom_score",  S_IRUGO, proc_oom_score),
2800         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
2801         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2802 #ifdef CONFIG_AUDITSYSCALL
2803         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2804         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2805 #endif
2806 #ifdef CONFIG_FAULT_INJECTION
2807         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2808 #endif
2809 #ifdef CONFIG_ELF_CORE
2810         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2811 #endif
2812 #ifdef CONFIG_TASK_IO_ACCOUNTING
2813         INF("io",       S_IRUGO, proc_tgid_io_accounting),
2814 #endif
2815 };
2816
2817 static int proc_tgid_base_readdir(struct file * filp,
2818                              void * dirent, filldir_t filldir)
2819 {
2820         return proc_pident_readdir(filp,dirent,filldir,
2821                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2822 }
2823
2824 static const struct file_operations proc_tgid_base_operations = {
2825         .read           = generic_read_dir,
2826         .readdir        = proc_tgid_base_readdir,
2827         .llseek         = default_llseek,
2828 };
2829
2830 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2831         return proc_pident_lookup(dir, dentry,
2832                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2833 }
2834
2835 static const struct inode_operations proc_tgid_base_inode_operations = {
2836         .lookup         = proc_tgid_base_lookup,
2837         .getattr        = pid_getattr,
2838         .setattr        = proc_setattr,
2839 };
2840
2841 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2842 {
2843         struct dentry *dentry, *leader, *dir;
2844         char buf[PROC_NUMBUF];
2845         struct qstr name;
2846
2847         name.name = buf;
2848         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2849         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2850         if (dentry) {
2851                 shrink_dcache_parent(dentry);
2852                 d_drop(dentry);
2853                 dput(dentry);
2854         }
2855
2856         name.name = buf;
2857         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2858         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2859         if (!leader)
2860                 goto out;
2861
2862         name.name = "task";
2863         name.len = strlen(name.name);
2864         dir = d_hash_and_lookup(leader, &name);
2865         if (!dir)
2866                 goto out_put_leader;
2867
2868         name.name = buf;
2869         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2870         dentry = d_hash_and_lookup(dir, &name);
2871         if (dentry) {
2872                 shrink_dcache_parent(dentry);
2873                 d_drop(dentry);
2874                 dput(dentry);
2875         }
2876
2877         dput(dir);
2878 out_put_leader:
2879         dput(leader);
2880 out:
2881         return;
2882 }
2883
2884 /**
2885  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2886  * @task: task that should be flushed.
2887  *
2888  * When flushing dentries from proc, one needs to flush them from global
2889  * proc (proc_mnt) and from all the namespaces' procs this task was seen
2890  * in. This call is supposed to do all of this job.
2891  *
2892  * Looks in the dcache for
2893  * /proc/@pid
2894  * /proc/@tgid/task/@pid
2895  * if either directory is present flushes it and all of it'ts children
2896  * from the dcache.
2897  *
2898  * It is safe and reasonable to cache /proc entries for a task until
2899  * that task exits.  After that they just clog up the dcache with
2900  * useless entries, possibly causing useful dcache entries to be
2901  * flushed instead.  This routine is proved to flush those useless
2902  * dcache entries at process exit time.
2903  *
2904  * NOTE: This routine is just an optimization so it does not guarantee
2905  *       that no dcache entries will exist at process exit time it
2906  *       just makes it very unlikely that any will persist.
2907  */
2908
2909 void proc_flush_task(struct task_struct *task)
2910 {
2911         int i;
2912         struct pid *pid, *tgid;
2913         struct upid *upid;
2914
2915         pid = task_pid(task);
2916         tgid = task_tgid(task);
2917
2918         for (i = 0; i <= pid->level; i++) {
2919                 upid = &pid->numbers[i];
2920                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2921                                         tgid->numbers[i].nr);
2922         }
2923
2924         upid = &pid->numbers[pid->level];
2925         if (upid->nr == 1)
2926                 pid_ns_release_proc(upid->ns);
2927 }
2928
2929 static struct dentry *proc_pid_instantiate(struct inode *dir,
2930                                            struct dentry * dentry,
2931                                            struct task_struct *task, const void *ptr)
2932 {
2933         struct dentry *error = ERR_PTR(-ENOENT);
2934         struct inode *inode;
2935
2936         inode = proc_pid_make_inode(dir->i_sb, task);
2937         if (!inode)
2938                 goto out;
2939
2940         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2941         inode->i_op = &proc_tgid_base_inode_operations;
2942         inode->i_fop = &proc_tgid_base_operations;
2943         inode->i_flags|=S_IMMUTABLE;
2944
2945         inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
2946                 ARRAY_SIZE(tgid_base_stuff));
2947
2948         d_set_d_op(dentry, &pid_dentry_operations);
2949
2950         d_add(dentry, inode);
2951         /* Close the race of the process dying before we return the dentry */
2952         if (pid_revalidate(dentry, NULL))
2953                 error = NULL;
2954 out:
2955         return error;
2956 }
2957
2958 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2959 {
2960         struct dentry *result;
2961         struct task_struct *task;
2962         unsigned tgid;
2963         struct pid_namespace *ns;
2964
2965         result = proc_base_lookup(dir, dentry);
2966         if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
2967                 goto out;
2968
2969         tgid = name_to_int(dentry);
2970         if (tgid == ~0U)
2971                 goto out;
2972
2973         ns = dentry->d_sb->s_fs_info;
2974         rcu_read_lock();
2975         task = find_task_by_pid_ns(tgid, ns);
2976         if (task)
2977                 get_task_struct(task);
2978         rcu_read_unlock();
2979         if (!task)
2980                 goto out;
2981
2982         result = proc_pid_instantiate(dir, dentry, task, NULL);
2983         put_task_struct(task);
2984 out:
2985         return result;
2986 }
2987
2988 /*
2989  * Find the first task with tgid >= tgid
2990  *
2991  */
2992 struct tgid_iter {
2993         unsigned int tgid;
2994         struct task_struct *task;
2995 };
2996 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
2997 {
2998         struct pid *pid;
2999
3000         if (iter.task)
3001                 put_task_struct(iter.task);
3002         rcu_read_lock();
3003 retry:
3004         iter.task = NULL;
3005         pid = find_ge_pid(iter.tgid, ns);
3006         if (pid) {
3007                 iter.tgid = pid_nr_ns(pid, ns);
3008                 iter.task = pid_task(pid, PIDTYPE_PID);
3009                 /* What we to know is if the pid we have find is the
3010                  * pid of a thread_group_leader.  Testing for task
3011                  * being a thread_group_leader is the obvious thing
3012                  * todo but there is a window when it fails, due to
3013                  * the pid transfer logic in de_thread.
3014                  *
3015                  * So we perform the straight forward test of seeing
3016                  * if the pid we have found is the pid of a thread
3017                  * group leader, and don't worry if the task we have
3018                  * found doesn't happen to be a thread group leader.
3019                  * As we don't care in the case of readdir.
3020                  */
3021                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3022                         iter.tgid += 1;
3023                         goto retry;
3024                 }
3025                 get_task_struct(iter.task);
3026         }
3027         rcu_read_unlock();
3028         return iter;
3029 }
3030
3031 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
3032
3033 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3034         struct tgid_iter iter)
3035 {
3036         char name[PROC_NUMBUF];
3037         int len = snprintf(name, sizeof(name), "%d", iter.tgid);
3038         return proc_fill_cache(filp, dirent, filldir, name, len,
3039                                 proc_pid_instantiate, iter.task, NULL);
3040 }
3041
3042 /* for the /proc/ directory itself, after non-process stuff has been done */
3043 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
3044 {
3045         unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
3046         struct task_struct *reaper = get_proc_task(filp->f_path.dentry->d_inode);
3047         struct tgid_iter iter;
3048         struct pid_namespace *ns;
3049
3050         if (!reaper)
3051                 goto out_no_task;
3052
3053         for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
3054                 const struct pid_entry *p = &proc_base_stuff[nr];
3055                 if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
3056                         goto out;
3057         }
3058
3059         ns = filp->f_dentry->d_sb->s_fs_info;
3060         iter.task = NULL;
3061         iter.tgid = filp->f_pos - TGID_OFFSET;
3062         for (iter = next_tgid(ns, iter);
3063              iter.task;
3064              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3065                 filp->f_pos = iter.tgid + TGID_OFFSET;
3066                 if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
3067                         put_task_struct(iter.task);
3068                         goto out;
3069                 }
3070         }
3071         filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
3072 out:
3073         put_task_struct(reaper);
3074 out_no_task:
3075         return 0;
3076 }
3077
3078 /*
3079  * Tasks
3080  */
3081 static const struct pid_entry tid_base_stuff[] = {
3082         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3083         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3084         REG("environ",   S_IRUSR, proc_environ_operations),
3085         INF("auxv",      S_IRUSR, proc_pid_auxv),
3086         ONE("status",    S_IRUGO, proc_pid_status),
3087         ONE("personality", S_IRUSR, proc_pid_personality),
3088         INF("limits",    S_IRUGO, proc_pid_limits),
3089 #ifdef CONFIG_SCHED_DEBUG
3090         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3091 #endif
3092         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3093 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3094         INF("syscall",   S_IRUSR, proc_pid_syscall),
3095 #endif
3096         INF("cmdline",   S_IRUGO, proc_pid_cmdline),
3097         ONE("stat",      S_IRUGO, proc_tid_stat),
3098         ONE("statm",     S_IRUGO, proc_pid_statm),
3099         REG("maps",      S_IRUGO, proc_maps_operations),
3100 #ifdef CONFIG_NUMA
3101         REG("numa_maps", S_IRUGO, proc_numa_maps_operations),
3102 #endif
3103         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3104         LNK("cwd",       proc_cwd_link),
3105         LNK("root",      proc_root_link),
3106         LNK("exe",       proc_exe_link),
3107         REG("mounts",    S_IRUGO, proc_mounts_operations),
3108         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3109 #ifdef CONFIG_PROC_PAGE_MONITOR
3110         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3111         REG("smaps",     S_IRUGO, proc_smaps_operations),
3112         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3113 #endif
3114 #ifdef CONFIG_SECURITY
3115         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3116 #endif
3117 #ifdef CONFIG_KALLSYMS
3118         INF("wchan",     S_IRUGO, proc_pid_wchan),
3119 #endif
3120 #ifdef CONFIG_STACKTRACE
3121         ONE("stack",      S_IRUSR, proc_pid_stack),
3122 #endif
3123 #ifdef CONFIG_SCHEDSTATS
3124         INF("schedstat", S_IRUGO, proc_pid_schedstat),
3125 #endif
3126 #ifdef CONFIG_LATENCYTOP
3127         REG("latency",  S_IRUGO, proc_lstats_operations),
3128 #endif
3129 #ifdef CONFIG_PROC_PID_CPUSET
3130         REG("cpuset",    S_IRUGO, proc_cpuset_operations),
3131 #endif
3132 #ifdef CONFIG_CGROUPS
3133         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3134 #endif
3135         INF("oom_score", S_IRUGO, proc_oom_score),
3136         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
3137         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3138 #ifdef CONFIG_AUDITSYSCALL
3139         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3140         REG("sessionid",  S_IRUSR, proc_sessionid_operations),
3141 #endif
3142 #ifdef CONFIG_FAULT_INJECTION
3143         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3144 #endif
3145 #ifdef CONFIG_TASK_IO_ACCOUNTING
3146         INF("io",       S_IRUGO, proc_tid_io_accounting),
3147 #endif
3148 };
3149
3150 static int proc_tid_base_readdir(struct file * filp,
3151                              void * dirent, filldir_t filldir)
3152 {
3153         return proc_pident_readdir(filp,dirent,filldir,
3154                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
3155 }
3156
3157 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
3158         return proc_pident_lookup(dir, dentry,
3159                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3160 }
3161
3162 static const struct file_operations proc_tid_base_operations = {
3163         .read           = generic_read_dir,
3164         .readdir        = proc_tid_base_readdir,
3165         .llseek         = default_llseek,
3166 };
3167
3168 static const struct inode_operations proc_tid_base_inode_operations = {
3169         .lookup         = proc_tid_base_lookup,
3170         .getattr        = pid_getattr,
3171         .setattr        = proc_setattr,
3172 };
3173
3174 static struct dentry *proc_task_instantiate(struct inode *dir,
3175         struct dentry *dentry, struct task_struct *task, const void *ptr)
3176 {
3177         struct dentry *error = ERR_PTR(-ENOENT);
3178         struct inode *inode;
3179         inode = proc_pid_make_inode(dir->i_sb, task);
3180
3181         if (!inode)
3182                 goto out;
3183         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3184         inode->i_op = &proc_tid_base_inode_operations;
3185         inode->i_fop = &proc_tid_base_operations;
3186         inode->i_flags|=S_IMMUTABLE;
3187
3188         inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
3189                 ARRAY_SIZE(tid_base_stuff));
3190
3191         d_set_d_op(dentry, &pid_dentry_operations);
3192
3193         d_add(dentry, inode);
3194         /* Close the race of the process dying before we return the dentry */
3195         if (pid_revalidate(dentry, NULL))
3196                 error = NULL;
3197 out:
3198         return error;
3199 }
3200
3201 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3202 {
3203         struct dentry *result = ERR_PTR(-ENOENT);
3204         struct task_struct *task;
3205         struct task_struct *leader = get_proc_task(dir);
3206         unsigned tid;
3207         struct pid_namespace *ns;
3208
3209         if (!leader)
3210                 goto out_no_task;
3211
3212         tid = name_to_int(dentry);
3213         if (tid == ~0U)
3214                 goto out;
3215
3216         ns = dentry->d_sb->s_fs_info;
3217         rcu_read_lock();
3218         task = find_task_by_pid_ns(tid, ns);
3219         if (task)
3220                 get_task_struct(task);
3221         rcu_read_unlock();
3222         if (!task)
3223                 goto out;
3224         if (!same_thread_group(leader, task))
3225                 goto out_drop_task;
3226
3227         result = proc_task_instantiate(dir, dentry, task, NULL);
3228 out_drop_task:
3229         put_task_struct(task);
3230 out:
3231         put_task_struct(leader);
3232 out_no_task:
3233         return result;
3234 }
3235
3236 /*
3237  * Find the first tid of a thread group to return to user space.
3238  *
3239  * Usually this is just the thread group leader, but if the users
3240  * buffer was too small or there was a seek into the middle of the
3241  * directory we have more work todo.
3242  *
3243  * In the case of a short read we start with find_task_by_pid.
3244  *
3245  * In the case of a seek we start with the leader and walk nr
3246  * threads past it.
3247  */
3248 static struct task_struct *first_tid(struct task_struct *leader,
3249                 int tid, int nr, struct pid_namespace *ns)
3250 {
3251         struct task_struct *pos;
3252
3253         rcu_read_lock();
3254         /* Attempt to start with the pid of a thread */
3255         if (tid && (nr > 0)) {
3256                 pos = find_task_by_pid_ns(tid, ns);
3257                 if (pos && (pos->group_leader == leader))
3258                         goto found;
3259         }
3260
3261         /* If nr exceeds the number of threads there is nothing todo */
3262         pos = NULL;
3263         if (nr && nr >= get_nr_threads(leader))
3264                 goto out;
3265
3266         /* If we haven't found our starting place yet start
3267          * with the leader and walk nr threads forward.
3268          */
3269         for (pos = leader; nr > 0; --nr) {
3270                 pos = next_thread(pos);
3271                 if (pos == leader) {
3272                         pos = NULL;
3273                         goto out;
3274                 }
3275         }
3276 found:
3277         get_task_struct(pos);
3278 out:
3279         rcu_read_unlock();
3280         return pos;
3281 }
3282
3283 /*
3284  * Find the next thread in the thread list.
3285  * Return NULL if there is an error or no next thread.
3286  *
3287  * The reference to the input task_struct is released.
3288  */
3289 static struct task_struct *next_tid(struct task_struct *start)
3290 {
3291         struct task_struct *pos = NULL;
3292         rcu_read_lock();
3293         if (pid_alive(start)) {
3294                 pos = next_thread(start);
3295                 if (thread_group_leader(pos))
3296                         pos = NULL;
3297                 else
3298                         get_task_struct(pos);
3299         }
3300         rcu_read_unlock();
3301         put_task_struct(start);
3302         return pos;
3303 }
3304
3305 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3306         struct task_struct *task, int tid)
3307 {
3308         char name[PROC_NUMBUF];
3309         int len = snprintf(name, sizeof(name), "%d", tid);
3310         return proc_fill_cache(filp, dirent, filldir, name, len,
3311                                 proc_task_instantiate, task, NULL);
3312 }
3313
3314 /* for the /proc/TGID/task/ directories */
3315 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3316 {
3317         struct dentry *dentry = filp->f_path.dentry;
3318         struct inode *inode = dentry->d_inode;
3319         struct task_struct *leader = NULL;
3320         struct task_struct *task;
3321         int retval = -ENOENT;
3322         ino_t ino;
3323         int tid;
3324         struct pid_namespace *ns;
3325
3326         task = get_proc_task(inode);
3327         if (!task)
3328                 goto out_no_task;
3329         rcu_read_lock();
3330         if (pid_alive(task)) {
3331                 leader = task->group_leader;
3332                 get_task_struct(leader);
3333         }
3334         rcu_read_unlock();
3335         put_task_struct(task);
3336         if (!leader)
3337                 goto out_no_task;
3338         retval = 0;
3339
3340         switch ((unsigned long)filp->f_pos) {
3341         case 0:
3342                 ino = inode->i_ino;
3343                 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) < 0)
3344                         goto out;
3345                 filp->f_pos++;
3346                 /* fall through */
3347         case 1:
3348                 ino = parent_ino(dentry);
3349                 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) < 0)
3350                         goto out;
3351                 filp->f_pos++;
3352                 /* fall through */
3353         }
3354
3355         /* f_version caches the tgid value that the last readdir call couldn't
3356          * return. lseek aka telldir automagically resets f_version to 0.
3357          */
3358         ns = filp->f_dentry->d_sb->s_fs_info;
3359         tid = (int)filp->f_version;
3360         filp->f_version = 0;
3361         for (task = first_tid(leader, tid, filp->f_pos - 2, ns);
3362              task;
3363              task = next_tid(task), filp->f_pos++) {
3364                 tid = task_pid_nr_ns(task, ns);
3365                 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3366                         /* returning this tgid failed, save it as the first
3367                          * pid for the next readir call */
3368                         filp->f_version = (u64)tid;
3369                         put_task_struct(task);
3370                         break;
3371                 }
3372         }
3373 out:
3374         put_task_struct(leader);
3375 out_no_task:
3376         return retval;
3377 }
3378
3379 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3380 {
3381         struct inode *inode = dentry->d_inode;
3382         struct task_struct *p = get_proc_task(inode);
3383         generic_fillattr(inode, stat);
3384
3385         if (p) {
3386                 stat->nlink += get_nr_threads(p);
3387                 put_task_struct(p);
3388         }
3389
3390         return 0;
3391 }
3392
3393 static const struct inode_operations proc_task_inode_operations = {
3394         .lookup         = proc_task_lookup,
3395         .getattr        = proc_task_getattr,
3396         .setattr        = proc_setattr,
3397 };
3398
3399 static const struct file_operations proc_task_operations = {
3400         .read           = generic_read_dir,
3401         .readdir        = proc_task_readdir,
3402         .llseek         = default_llseek,
3403 };