Pileus Git - ~andy/linux/blob - 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/user_namespace.h>
  85 #include <linux/fs_struct.h>
  86 #include <linux/slab.h>
  87 #include <linux/flex_array.h>
  88 #ifdef CONFIG_HARDWALL
  89 #include <asm/hardwall.h>
  90 #endif
  91 #include <trace/events/oom.h>
  92 #include "internal.h"
  93
  94 /* NOTE:
  95  *      Implementing inode permission operations in /proc is almost
  96  *      certainly an error.  Permission checks need to happen during
  97  *      each system call not at open time.  The reason is that most of
  98  *      what we wish to check for permissions in /proc varies at runtime.
  99  *
 100  *      The classic example of a problem is opening file descriptors
 101  *      in /proc for a task before it execs a suid executable.
 102  */
 103
 104 struct pid_entry {
 105         char *name;
 106         int len;
 107         umode_t mode;
 108         const struct inode_operations *iop;
 109         const struct file_operations *fop;
 110         union proc_op op;
 111 };
 112
 113 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 114         .name = (NAME),                                 \
 115         .len  = sizeof(NAME) - 1,                       \
 116         .mode = MODE,                                   \
 117         .iop  = IOP,                                    \
 118         .fop  = FOP,                                    \
 119         .op   = OP,                                     \
 120 }
 121
 122 #define DIR(NAME, MODE, iops, fops)     \
 123         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 124 #define LNK(NAME, get_link)                                     \
 125         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 126                 &proc_pid_link_inode_operations, NULL,          \
 127                 { .proc_get_link = get_link } )
 128 #define REG(NAME, MODE, fops)                           \
 129         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 130 #define INF(NAME, MODE, read)                           \
 131         NOD(NAME, (S_IFREG|(MODE)),                     \
 132                 NULL, &proc_info_file_operations,       \
 133                 { .proc_read = read } )
 134 #define ONE(NAME, MODE, show)                           \
 135         NOD(NAME, (S_IFREG|(MODE)),                     \
 136                 NULL, &proc_single_file_operations,     \
 137                 { .proc_show = show } )
 138
 139 static int proc_fd_permission(struct inode *inode, int mask);
 140
 141 /*
 142  * Count the number of hardlinks for the pid_entry table, excluding the .
 143  * and .. links.
 144  */
 145 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
 146         unsigned int n)
 147 {
 148         unsigned int i;
 149         unsigned int count;
 150
 151         count = 0;
 152         for (i = 0; i < n; ++i) {
 153                 if (S_ISDIR(entries[i].mode))
 154                         ++count;
 155         }
 156
 157         return count;
 158 }
 159
 160 static int get_task_root(struct task_struct *task, struct path *root)
 161 {
 162         int result = -ENOENT;
 163
 164         task_lock(task);
 165         if (task->fs) {
 166                 get_fs_root(task->fs, root);
 167                 result = 0;
 168         }
 169         task_unlock(task);
 170         return result;
 171 }
 172
 173 static int proc_cwd_link(struct dentry *dentry, struct path *path)
 174 {
 175         struct task_struct *task = get_proc_task(dentry->d_inode);
 176         int result = -ENOENT;
 177
 178         if (task) {
 179                 task_lock(task);
 180                 if (task->fs) {
 181                         get_fs_pwd(task->fs, path);
 182                         result = 0;
 183                 }
 184                 task_unlock(task);
 185                 put_task_struct(task);
 186         }
 187         return result;
 188 }
 189
 190 static int proc_root_link(struct dentry *dentry, struct path *path)
 191 {
 192         struct task_struct *task = get_proc_task(dentry->d_inode);
 193         int result = -ENOENT;
 194
 195         if (task) {
 196                 result = get_task_root(task, path);
 197                 put_task_struct(task);
 198         }
 199         return result;
 200 }
 201
 202 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 203 {
 204         int res = 0;
 205         unsigned int len;
 206         struct mm_struct *mm = get_task_mm(task);
 207         if (!mm)
 208                 goto out;
 209         if (!mm->arg_end)
 210                 goto out_mm;    /* Shh! No looking before we're done */
 211
 212         len = mm->arg_end - mm->arg_start;
 213
 214         if (len > PAGE_SIZE)
 215                 len = PAGE_SIZE;
 216
 217         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 218
 219         // If the nul at the end of args has been overwritten, then
 220         // assume application is using setproctitle(3).
 221         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 222                 len = strnlen(buffer, res);
 223                 if (len < res) {
 224                     res = len;
 225                 } else {
 226                         len = mm->env_end - mm->env_start;
 227                         if (len > PAGE_SIZE - res)
 228                                 len = PAGE_SIZE - res;
 229                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 230                         res = strnlen(buffer, res);
 231                 }
 232         }
 233 out_mm:
 234         mmput(mm);
 235 out:
 236         return res;
 237 }
 238
 239 static int proc_pid_auxv(struct task_struct *task, char *buffer)
 240 {
 241         struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ);
 242         int res = PTR_ERR(mm);
 243         if (mm && !IS_ERR(mm)) {
 244                 unsigned int nwords = 0;
 245                 do {
 246                         nwords += 2;
 247                 } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 248                 res = nwords * sizeof(mm->saved_auxv[0]);
 249                 if (res > PAGE_SIZE)
 250                         res = PAGE_SIZE;
 251                 memcpy(buffer, mm->saved_auxv, res);
 252                 mmput(mm);
 253         }
 254         return res;
 255 }
 256
 257
 258 #ifdef CONFIG_KALLSYMS
 259 /*
 260  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 261  * Returns the resolved symbol.  If that fails, simply return the address.
 262  */
 263 static int proc_pid_wchan(struct task_struct *task, char *buffer)
 264 {
 265         unsigned long wchan;
 266         char symname[KSYM_NAME_LEN];
 267
 268         wchan = get_wchan(task);
 269
 270         if (lookup_symbol_name(wchan, symname) < 0)
 271                 if (!ptrace_may_access(task, PTRACE_MODE_READ))
 272                         return 0;
 273                 else
 274                         return sprintf(buffer, "%lu", wchan);
 275         else
 276                 return sprintf(buffer, "%s", symname);
 277 }
 278 #endif /* CONFIG_KALLSYMS */
 279
 280 static int lock_trace(struct task_struct *task)
 281 {
 282         int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 283         if (err)
 284                 return err;
 285         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
 286                 mutex_unlock(&task->signal->cred_guard_mutex);
 287                 return -EPERM;
 288         }
 289         return 0;
 290 }
 291
 292 static void unlock_trace(struct task_struct *task)
 293 {
 294         mutex_unlock(&task->signal->cred_guard_mutex);
 295 }
 296
 297 #ifdef CONFIG_STACKTRACE
 298
 299 #define MAX_STACK_TRACE_DEPTH   64
 300
 301 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 302                           struct pid *pid, struct task_struct *task)
 303 {
 304         struct stack_trace trace;
 305         unsigned long *entries;
 306         int err;
 307         int i;
 308
 309         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 310         if (!entries)
 311                 return -ENOMEM;
 312
 313         trace.nr_entries        = 0;
 314         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 315         trace.entries           = entries;
 316         trace.skip              = 0;
 317
 318         err = lock_trace(task);
 319         if (!err) {
 320                 save_stack_trace_tsk(task, &trace);
 321
 322                 for (i = 0; i < trace.nr_entries; i++) {
 323                         seq_printf(m, "[<%pK>] %pS\n",
 324                                    (void *)entries[i], (void *)entries[i]);
 325                 }
 326                 unlock_trace(task);
 327         }
 328         kfree(entries);
 329
 330         return err;
 331 }
 332 #endif
 333
 334 #ifdef CONFIG_SCHEDSTATS
 335 /*
 336  * Provides /proc/PID/schedstat
 337  */
 338 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 339 {
 340         return sprintf(buffer, "%llu %llu %lu\n",
 341                         (unsigned long long)task->se.sum_exec_runtime,
 342                         (unsigned long long)task->sched_info.run_delay,
 343                         task->sched_info.pcount);
 344 }
 345 #endif
 346
 347 #ifdef CONFIG_LATENCYTOP
 348 static int lstats_show_proc(struct seq_file *m, void *v)
 349 {
 350         int i;
 351         struct inode *inode = m->private;
 352         struct task_struct *task = get_proc_task(inode);
 353
 354         if (!task)
 355                 return -ESRCH;
 356         seq_puts(m, "Latency Top version : v0.1\n");
 357         for (i = 0; i < 32; i++) {
 358                 struct latency_record *lr = &task->latency_record[i];
 359                 if (lr->backtrace[0]) {
 360                         int q;
 361                         seq_printf(m, "%i %li %li",
 362                                    lr->count, lr->time, lr->max);
 363                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 364                                 unsigned long bt = lr->backtrace[q];
 365                                 if (!bt)
 366                                         break;
 367                                 if (bt == ULONG_MAX)
 368                                         break;
 369                                 seq_printf(m, " %ps", (void *)bt);
 370                         }
 371                         seq_putc(m, '\n');
 372                 }
 373
 374         }
 375         put_task_struct(task);
 376         return 0;
 377 }
 378
 379 static int lstats_open(struct inode *inode, struct file *file)
 380 {
 381         return single_open(file, lstats_show_proc, inode);
 382 }
 383
 384 static ssize_t lstats_write(struct file *file, const char __user *buf,
 385                             size_t count, loff_t *offs)
 386 {
 387         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 388
 389         if (!task)
 390                 return -ESRCH;
 391         clear_all_latency_tracing(task);
 392         put_task_struct(task);
 393
 394         return count;
 395 }
 396
 397 static const struct file_operations proc_lstats_operations = {
 398         .open           = lstats_open,
 399         .read           = seq_read,
 400         .write          = lstats_write,
 401         .llseek         = seq_lseek,
 402         .release        = single_release,
 403 };
 404
 405 #endif
 406
 407 static int proc_oom_score(struct task_struct *task, char *buffer)
 408 {
 409         unsigned long totalpages = totalram_pages + total_swap_pages;
 410         unsigned long points = 0;
 411
 412         read_lock(&tasklist_lock);
 413         if (pid_alive(task))
 414                 points = oom_badness(task, NULL, NULL, totalpages) *
 415                                                 1000 / totalpages;
 416         read_unlock(&tasklist_lock);
 417         return sprintf(buffer, "%lu\n", points);
 418 }
 419
 420 struct limit_names {
 421         char *name;
 422         char *unit;
 423 };
 424
 425 static const struct limit_names lnames[RLIM_NLIMITS] = {
 426         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 427         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 428         [RLIMIT_DATA] = {"Max data size", "bytes"},
 429         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 430         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 431         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 432         [RLIMIT_NPROC] = {"Max processes", "processes"},
 433         [RLIMIT_NOFILE] = {"Max open files", "files"},
 434         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 435         [RLIMIT_AS] = {"Max address space", "bytes"},
 436         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 437         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 438         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 439         [RLIMIT_NICE] = {"Max nice priority", NULL},
 440         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 441         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 442 };
 443
 444 /* Display limits for a process */
 445 static int proc_pid_limits(struct task_struct *task, char *buffer)
 446 {
 447         unsigned int i;
 448         int count = 0;
 449         unsigned long flags;
 450         char *bufptr = buffer;
 451
 452         struct rlimit rlim[RLIM_NLIMITS];
 453
 454         if (!lock_task_sighand(task, &flags))
 455                 return 0;
 456         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 457         unlock_task_sighand(task, &flags);
 458
 459         /*
 460          * print the file header
 461          */
 462         count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
 463                         "Limit", "Soft Limit", "Hard Limit", "Units");
 464
 465         for (i = 0; i < RLIM_NLIMITS; i++) {
 466                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 467                         count += sprintf(&bufptr[count], "%-25s %-20s ",
 468                                          lnames[i].name, "unlimited");
 469                 else
 470                         count += sprintf(&bufptr[count], "%-25s %-20lu ",
 471                                          lnames[i].name, rlim[i].rlim_cur);
 472
 473                 if (rlim[i].rlim_max == RLIM_INFINITY)
 474                         count += sprintf(&bufptr[count], "%-20s ", "unlimited");
 475                 else
 476                         count += sprintf(&bufptr[count], "%-20lu ",
 477                                          rlim[i].rlim_max);
 478
 479                 if (lnames[i].unit)
 480                         count += sprintf(&bufptr[count], "%-10s\n",
 481                                          lnames[i].unit);
 482                 else
 483                         count += sprintf(&bufptr[count], "\n");
 484         }
 485
 486         return count;
 487 }
 488
 489 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 490 static int proc_pid_syscall(struct task_struct *task, char *buffer)
 491 {
 492         long nr;
 493         unsigned long args[6], sp, pc;
 494         int res = lock_trace(task);
 495         if (res)
 496                 return res;
 497
 498         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 499                 res = sprintf(buffer, "running\n");
 500         else if (nr < 0)
 501                 res = sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 502         else
 503                 res = sprintf(buffer,
 504                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 505                        nr,
 506                        args[0], args[1], args[2], args[3], args[4], args[5],
 507                        sp, pc);
 508         unlock_trace(task);
 509         return res;
 510 }
 511 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 512
 513 /************************************************************************/
 514 /*                       Here the fs part begins                        */
 515 /************************************************************************/
 516
 517 /* permission checks */
 518 static int proc_fd_access_allowed(struct inode *inode)
 519 {
 520         struct task_struct *task;
 521         int allowed = 0;
 522         /* Allow access to a task's file descriptors if it is us or we
 523          * may use ptrace attach to the process and find out that
 524          * information.
 525          */
 526         task = get_proc_task(inode);
 527         if (task) {
 528                 allowed = ptrace_may_access(task, PTRACE_MODE_READ);
 529                 put_task_struct(task);
 530         }
 531         return allowed;
 532 }
 533
 534 int proc_setattr(struct dentry *dentry, struct iattr *attr)
 535 {
 536         int error;
 537         struct inode *inode = dentry->d_inode;
 538
 539         if (attr->ia_valid & ATTR_MODE)
 540                 return -EPERM;
 541
 542         error = inode_change_ok(inode, attr);
 543         if (error)
 544                 return error;
 545
 546         if ((attr->ia_valid & ATTR_SIZE) &&
 547             attr->ia_size != i_size_read(inode)) {
 548                 error = vmtruncate(inode, attr->ia_size);
 549                 if (error)
 550                         return error;
 551         }
 552
 553         setattr_copy(inode, attr);
 554         mark_inode_dirty(inode);
 555         return 0;
 556 }
 557
 558 /*
 559  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 560  * or euid/egid (for hide_pid_min=2)?
 561  */
 562 static bool has_pid_permissions(struct pid_namespace *pid,
 563                                  struct task_struct *task,
 564                                  int hide_pid_min)
 565 {
 566         if (pid->hide_pid < hide_pid_min)
 567                 return true;
 568         if (in_group_p(pid->pid_gid))
 569                 return true;
 570         return ptrace_may_access(task, PTRACE_MODE_READ);
 571 }
 572
 573
 574 static int proc_pid_permission(struct inode *inode, int mask)
 575 {
 576         struct pid_namespace *pid = inode->i_sb->s_fs_info;
 577         struct task_struct *task;
 578         bool has_perms;
 579
 580         task = get_proc_task(inode);
 581         if (!task)
 582                 return -ESRCH;
 583         has_perms = has_pid_permissions(pid, task, 1);
 584         put_task_struct(task);
 585
 586         if (!has_perms) {
 587                 if (pid->hide_pid == 2) {
 588                         /*
 589                          * Let's make getdents(), stat(), and open()
 590                          * consistent with each other.  If a process
 591                          * may not stat() a file, it shouldn't be seen
 592                          * in procfs at all.
 593                          */
 594                         return -ENOENT;
 595                 }
 596
 597                 return -EPERM;
 598         }
 599         return generic_permission(inode, mask);
 600 }
 601
 602
 603
 604 static const struct inode_operations proc_def_inode_operations = {
 605         .setattr        = proc_setattr,
 606 };
 607
 608 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 609
 610 static ssize_t proc_info_read(struct file * file, char __user * buf,
 611                           size_t count, loff_t *ppos)
 612 {
 613         struct inode * inode = file->f_path.dentry->d_inode;
 614         unsigned long page;
 615         ssize_t length;
 616         struct task_struct *task = get_proc_task(inode);
 617
 618         length = -ESRCH;
 619         if (!task)
 620                 goto out_no_task;
 621
 622         if (count > PROC_BLOCK_SIZE)
 623                 count = PROC_BLOCK_SIZE;
 624
 625         length = -ENOMEM;
 626         if (!(page = __get_free_page(GFP_TEMPORARY)))
 627                 goto out;
 628
 629         length = PROC_I(inode)->op.proc_read(task, (char*)page);
 630
 631         if (length >= 0)
 632                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 633         free_page(page);
 634 out:
 635         put_task_struct(task);
 636 out_no_task:
 637         return length;
 638 }
 639
 640 static const struct file_operations proc_info_file_operations = {
 641         .read           = proc_info_read,
 642         .llseek         = generic_file_llseek,
 643 };
 644
 645 static int proc_single_show(struct seq_file *m, void *v)
 646 {
 647         struct inode *inode = m->private;
 648         struct pid_namespace *ns;
 649         struct pid *pid;
 650         struct task_struct *task;
 651         int ret;
 652
 653         ns = inode->i_sb->s_fs_info;
 654         pid = proc_pid(inode);
 655         task = get_pid_task(pid, PIDTYPE_PID);
 656         if (!task)
 657                 return -ESRCH;
 658
 659         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 660
 661         put_task_struct(task);
 662         return ret;
 663 }
 664
 665 static int proc_single_open(struct inode *inode, struct file *filp)
 666 {
 667         return single_open(filp, proc_single_show, inode);
 668 }
 669
 670 static const struct file_operations proc_single_file_operations = {
 671         .open           = proc_single_open,
 672         .read           = seq_read,
 673         .llseek         = seq_lseek,
 674         .release        = single_release,
 675 };
 676
 677 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 678 {
 679         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 680         struct mm_struct *mm;
 681
 682         if (!task)
 683                 return -ESRCH;
 684
 685         mm = mm_access(task, mode);
 686         put_task_struct(task);
 687
 688         if (IS_ERR(mm))
 689                 return PTR_ERR(mm);
 690
 691         if (mm) {
 692                 /* ensure this mm_struct can't be freed */
 693                 atomic_inc(&mm->mm_count);
 694                 /* but do not pin its memory */
 695                 mmput(mm);
 696         }
 697
 698         /* OK to pass negative loff_t, we can catch out-of-range */
 699         file->f_mode |= FMODE_UNSIGNED_OFFSET;
 700         file->private_data = mm;
 701
 702         return 0;
 703 }
 704
 705 static int mem_open(struct inode *inode, struct file *file)
 706 {
 707         return __mem_open(inode, file, PTRACE_MODE_ATTACH);
 708 }
 709
 710 static ssize_t mem_rw(struct file *file, char __user *buf,
 711                         size_t count, loff_t *ppos, int write)
 712 {
 713         struct mm_struct *mm = file->private_data;
 714         unsigned long addr = *ppos;
 715         ssize_t copied;
 716         char *page;
 717
 718         if (!mm)
 719                 return 0;
 720
 721         page = (char *)__get_free_page(GFP_TEMPORARY);
 722         if (!page)
 723                 return -ENOMEM;
 724
 725         copied = 0;
 726         if (!atomic_inc_not_zero(&mm->mm_users))
 727                 goto free;
 728
 729         while (count > 0) {
 730                 int this_len = min_t(int, count, PAGE_SIZE);
 731
 732                 if (write && copy_from_user(page, buf, this_len)) {
 733                         copied = -EFAULT;
 734                         break;
 735                 }
 736
 737                 this_len = access_remote_vm(mm, addr, page, this_len, write);
 738                 if (!this_len) {
 739                         if (!copied)
 740                                 copied = -EIO;
 741                         break;
 742                 }
 743
 744                 if (!write && copy_to_user(buf, page, this_len)) {
 745                         copied = -EFAULT;
 746                         break;
 747                 }
 748
 749                 buf += this_len;
 750                 addr += this_len;
 751                 copied += this_len;
 752                 count -= this_len;
 753         }
 754         *ppos = addr;
 755
 756         mmput(mm);
 757 free:
 758         free_page((unsigned long) page);
 759         return copied;
 760 }
 761
 762 static ssize_t mem_read(struct file *file, char __user *buf,
 763                         size_t count, loff_t *ppos)
 764 {
 765         return mem_rw(file, buf, count, ppos, 0);
 766 }
 767
 768 static ssize_t mem_write(struct file *file, const char __user *buf,
 769                          size_t count, loff_t *ppos)
 770 {
 771         return mem_rw(file, (char __user*)buf, count, ppos, 1);
 772 }
 773
 774 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 775 {
 776         switch (orig) {
 777         case 0:
 778                 file->f_pos = offset;
 779                 break;
 780         case 1:
 781                 file->f_pos += offset;
 782                 break;
 783         default:
 784                 return -EINVAL;
 785         }
 786         force_successful_syscall_return();
 787         return file->f_pos;
 788 }
 789
 790 static int mem_release(struct inode *inode, struct file *file)
 791 {
 792         struct mm_struct *mm = file->private_data;
 793         if (mm)
 794                 mmdrop(mm);
 795         return 0;
 796 }
 797
 798 static const struct file_operations proc_mem_operations = {
 799         .llseek         = mem_lseek,
 800         .read           = mem_read,
 801         .write          = mem_write,
 802         .open           = mem_open,
 803         .release        = mem_release,
 804 };
 805
 806 static int environ_open(struct inode *inode, struct file *file)
 807 {
 808         return __mem_open(inode, file, PTRACE_MODE_READ);
 809 }
 810
 811 static ssize_t environ_read(struct file *file, char __user *buf,
 812                         size_t count, loff_t *ppos)
 813 {
 814         char *page;
 815         unsigned long src = *ppos;
 816         int ret = 0;
 817         struct mm_struct *mm = file->private_data;
 818
 819         if (!mm)
 820                 return 0;
 821
 822         page = (char *)__get_free_page(GFP_TEMPORARY);
 823         if (!page)
 824                 return -ENOMEM;
 825
 826         ret = 0;
 827         if (!atomic_inc_not_zero(&mm->mm_users))
 828                 goto free;
 829         while (count > 0) {
 830                 int this_len, retval, max_len;
 831
 832                 this_len = mm->env_end - (mm->env_start + src);
 833
 834                 if (this_len <= 0)
 835                         break;
 836
 837                 max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 838                 this_len = (this_len > max_len) ? max_len : this_len;
 839
 840                 retval = access_remote_vm(mm, (mm->env_start + src),
 841                         page, this_len, 0);
 842
 843                 if (retval <= 0) {
 844                         ret = retval;
 845                         break;
 846                 }
 847
 848                 if (copy_to_user(buf, page, retval)) {
 849                         ret = -EFAULT;
 850                         break;
 851                 }
 852
 853                 ret += retval;
 854                 src += retval;
 855                 buf += retval;
 856                 count -= retval;
 857         }
 858         *ppos = src;
 859         mmput(mm);
 860
 861 free:
 862         free_page((unsigned long) page);
 863         return ret;
 864 }
 865
 866 static const struct file_operations proc_environ_operations = {
 867         .open           = environ_open,
 868         .read           = environ_read,
 869         .llseek         = generic_file_llseek,
 870         .release        = mem_release,
 871 };
 872
 873 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
 874                                 size_t count, loff_t *ppos)
 875 {
 876         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 877         char buffer[PROC_NUMBUF];
 878         size_t len;
 879         int oom_adjust = OOM_DISABLE;
 880         unsigned long flags;
 881
 882         if (!task)
 883                 return -ESRCH;
 884
 885         if (lock_task_sighand(task, &flags)) {
 886                 oom_adjust = task->signal->oom_adj;
 887                 unlock_task_sighand(task, &flags);
 888         }
 889
 890         put_task_struct(task);
 891
 892         len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
 893
 894         return simple_read_from_buffer(buf, count, ppos, buffer, len);
 895 }
 896
 897 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 898                                 size_t count, loff_t *ppos)
 899 {
 900         struct task_struct *task;
 901         char buffer[PROC_NUMBUF];
 902         int oom_adjust;
 903         unsigned long flags;
 904         int err;
 905
 906         memset(buffer, 0, sizeof(buffer));
 907         if (count > sizeof(buffer) - 1)
 908                 count = sizeof(buffer) - 1;
 909         if (copy_from_user(buffer, buf, count)) {
 910                 err = -EFAULT;
 911                 goto out;
 912         }
 913
 914         err = kstrtoint(strstrip(buffer), 0, &oom_adjust);
 915         if (err)
 916                 goto out;
 917         if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
 918              oom_adjust != OOM_DISABLE) {
 919                 err = -EINVAL;
 920                 goto out;
 921         }
 922
 923         task = get_proc_task(file->f_path.dentry->d_inode);
 924         if (!task) {
 925                 err = -ESRCH;
 926                 goto out;
 927         }
 928
 929         task_lock(task);
 930         if (!task->mm) {
 931                 err = -EINVAL;
 932                 goto err_task_lock;
 933         }
 934
 935         if (!lock_task_sighand(task, &flags)) {
 936                 err = -ESRCH;
 937                 goto err_task_lock;
 938         }
 939
 940         if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
 941                 err = -EACCES;
 942                 goto err_sighand;
 943         }
 944
 945         /*
 946          * Warn that /proc/pid/oom_adj is deprecated, see
 947          * Documentation/feature-removal-schedule.txt.
 948          */
 949         printk_once(KERN_WARNING "%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
 950                   current->comm, task_pid_nr(current), task_pid_nr(task),
 951                   task_pid_nr(task));
 952         task->signal->oom_adj = oom_adjust;
 953         /*
 954          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
 955          * value is always attainable.
 956          */
 957         if (task->signal->oom_adj == OOM_ADJUST_MAX)
 958                 task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX;
 959         else
 960                 task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
 961                                                                 -OOM_DISABLE;
 962         trace_oom_score_adj_update(task);
 963 err_sighand:
 964         unlock_task_sighand(task, &flags);
 965 err_task_lock:
 966         task_unlock(task);
 967         put_task_struct(task);
 968 out:
 969         return err < 0 ? err : count;
 970 }
 971
 972 static const struct file_operations proc_oom_adjust_operations = {
 973         .read           = oom_adjust_read,
 974         .write          = oom_adjust_write,
 975         .llseek         = generic_file_llseek,
 976 };
 977
 978 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
 979                                         size_t count, loff_t *ppos)
 980 {
 981         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 982         char buffer[PROC_NUMBUF];
 983         int oom_score_adj = OOM_SCORE_ADJ_MIN;
 984         unsigned long flags;
 985         size_t len;
 986
 987         if (!task)
 988                 return -ESRCH;
 989         if (lock_task_sighand(task, &flags)) {
 990                 oom_score_adj = task->signal->oom_score_adj;
 991                 unlock_task_sighand(task, &flags);
 992         }
 993         put_task_struct(task);
 994         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj);
 995         return simple_read_from_buffer(buf, count, ppos, buffer, len);
 996 }
 997
 998 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
 999                                         size_t count, loff_t *ppos)
1000 {
1001         struct task_struct *task;
1002         char buffer[PROC_NUMBUF];
1003         unsigned long flags;
1004         int oom_score_adj;
1005         int err;
1006
1007         memset(buffer, 0, sizeof(buffer));
1008         if (count > sizeof(buffer) - 1)
1009                 count = sizeof(buffer) - 1;
1010         if (copy_from_user(buffer, buf, count)) {
1011                 err = -EFAULT;
1012                 goto out;
1013         }
1014
1015         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1016         if (err)
1017                 goto out;
1018         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1019                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1020                 err = -EINVAL;
1021                 goto out;
1022         }
1023
1024         task = get_proc_task(file->f_path.dentry->d_inode);
1025         if (!task) {
1026                 err = -ESRCH;
1027                 goto out;
1028         }
1029
1030         task_lock(task);
1031         if (!task->mm) {
1032                 err = -EINVAL;
1033                 goto err_task_lock;
1034         }
1035
1036         if (!lock_task_sighand(task, &flags)) {
1037                 err = -ESRCH;
1038                 goto err_task_lock;
1039         }
1040
1041         if (oom_score_adj < task->signal->oom_score_adj_min &&
1042                         !capable(CAP_SYS_RESOURCE)) {
1043                 err = -EACCES;
1044                 goto err_sighand;
1045         }
1046
1047         task->signal->oom_score_adj = oom_score_adj;
1048         if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1049                 task->signal->oom_score_adj_min = oom_score_adj;
1050         trace_oom_score_adj_update(task);
1051         /*
1052          * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
1053          * always attainable.
1054          */
1055         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1056                 task->signal->oom_adj = OOM_DISABLE;
1057         else
1058                 task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
1059                                                         OOM_SCORE_ADJ_MAX;
1060 err_sighand:
1061         unlock_task_sighand(task, &flags);
1062 err_task_lock:
1063         task_unlock(task);
1064         put_task_struct(task);
1065 out:
1066         return err < 0 ? err : count;
1067 }
1068
1069 static const struct file_operations proc_oom_score_adj_operations = {
1070         .read           = oom_score_adj_read,
1071         .write          = oom_score_adj_write,
1072         .llseek         = default_llseek,
1073 };
1074
1075 #ifdef CONFIG_AUDITSYSCALL
1076 #define TMPBUFLEN 21
1077 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1078                                   size_t count, loff_t *ppos)
1079 {
1080         struct inode * inode = file->f_path.dentry->d_inode;
1081         struct task_struct *task = get_proc_task(inode);
1082         ssize_t length;
1083         char tmpbuf[TMPBUFLEN];
1084
1085         if (!task)
1086                 return -ESRCH;
1087         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1088                                 audit_get_loginuid(task));
1089         put_task_struct(task);
1090         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1091 }
1092
1093 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1094                                    size_t count, loff_t *ppos)
1095 {
1096         struct inode * inode = file->f_path.dentry->d_inode;
1097         char *page, *tmp;
1098         ssize_t length;
1099         uid_t loginuid;
1100
1101         rcu_read_lock();
1102         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1103                 rcu_read_unlock();
1104                 return -EPERM;
1105         }
1106         rcu_read_unlock();
1107
1108         if (count >= PAGE_SIZE)
1109                 count = PAGE_SIZE - 1;
1110
1111         if (*ppos != 0) {
1112                 /* No partial writes. */
1113                 return -EINVAL;
1114         }
1115         page = (char*)__get_free_page(GFP_TEMPORARY);
1116         if (!page)
1117                 return -ENOMEM;
1118         length = -EFAULT;
1119         if (copy_from_user(page, buf, count))
1120                 goto out_free_page;
1121
1122         page[count] = '\0';
1123         loginuid = simple_strtoul(page, &tmp, 10);
1124         if (tmp == page) {
1125                 length = -EINVAL;
1126                 goto out_free_page;
1127
1128         }
1129         length = audit_set_loginuid(loginuid);
1130         if (likely(length == 0))
1131                 length = count;
1132
1133 out_free_page:
1134         free_page((unsigned long) page);
1135         return length;
1136 }
1137
1138 static const struct file_operations proc_loginuid_operations = {
1139         .read           = proc_loginuid_read,
1140         .write          = proc_loginuid_write,
1141         .llseek         = generic_file_llseek,
1142 };
1143
1144 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1145                                   size_t count, loff_t *ppos)
1146 {
1147         struct inode * inode = file->f_path.dentry->d_inode;
1148         struct task_struct *task = get_proc_task(inode);
1149         ssize_t length;
1150         char tmpbuf[TMPBUFLEN];
1151
1152         if (!task)
1153                 return -ESRCH;
1154         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1155                                 audit_get_sessionid(task));
1156         put_task_struct(task);
1157         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1158 }
1159
1160 static const struct file_operations proc_sessionid_operations = {
1161         .read           = proc_sessionid_read,
1162         .llseek         = generic_file_llseek,
1163 };
1164 #endif
1165
1166 #ifdef CONFIG_FAULT_INJECTION
1167 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1168                                       size_t count, loff_t *ppos)
1169 {
1170         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1171         char buffer[PROC_NUMBUF];
1172         size_t len;
1173         int make_it_fail;
1174
1175         if (!task)
1176                 return -ESRCH;
1177         make_it_fail = task->make_it_fail;
1178         put_task_struct(task);
1179
1180         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1181
1182         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1183 }
1184
1185 static ssize_t proc_fault_inject_write(struct file * file,
1186                         const char __user * buf, size_t count, loff_t *ppos)
1187 {
1188         struct task_struct *task;
1189         char buffer[PROC_NUMBUF], *end;
1190         int make_it_fail;
1191
1192         if (!capable(CAP_SYS_RESOURCE))
1193                 return -EPERM;
1194         memset(buffer, 0, sizeof(buffer));
1195         if (count > sizeof(buffer) - 1)
1196                 count = sizeof(buffer) - 1;
1197         if (copy_from_user(buffer, buf, count))
1198                 return -EFAULT;
1199         make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
1200         if (*end)
1201                 return -EINVAL;
1202         task = get_proc_task(file->f_dentry->d_inode);
1203         if (!task)
1204                 return -ESRCH;
1205         task->make_it_fail = make_it_fail;
1206         put_task_struct(task);
1207
1208         return count;
1209 }
1210
1211 static const struct file_operations proc_fault_inject_operations = {
1212         .read           = proc_fault_inject_read,
1213         .write          = proc_fault_inject_write,
1214         .llseek         = generic_file_llseek,
1215 };
1216 #endif
1217
1218
1219 #ifdef CONFIG_SCHED_DEBUG
1220 /*
1221  * Print out various scheduling related per-task fields:
1222  */
1223 static int sched_show(struct seq_file *m, void *v)
1224 {
1225         struct inode *inode = m->private;
1226         struct task_struct *p;
1227
1228         p = get_proc_task(inode);
1229         if (!p)
1230                 return -ESRCH;
1231         proc_sched_show_task(p, m);
1232
1233         put_task_struct(p);
1234
1235         return 0;
1236 }
1237
1238 static ssize_t
1239 sched_write(struct file *file, const char __user *buf,
1240             size_t count, loff_t *offset)
1241 {
1242         struct inode *inode = file->f_path.dentry->d_inode;
1243         struct task_struct *p;
1244
1245         p = get_proc_task(inode);
1246         if (!p)
1247                 return -ESRCH;
1248         proc_sched_set_task(p);
1249
1250         put_task_struct(p);
1251
1252         return count;
1253 }
1254
1255 static int sched_open(struct inode *inode, struct file *filp)
1256 {
1257         return single_open(filp, sched_show, inode);
1258 }
1259
1260 static const struct file_operations proc_pid_sched_operations = {
1261         .open           = sched_open,
1262         .read           = seq_read,
1263         .write          = sched_write,
1264         .llseek         = seq_lseek,
1265         .release        = single_release,
1266 };
1267
1268 #endif
1269
1270 #ifdef CONFIG_SCHED_AUTOGROUP
1271 /*
1272  * Print out autogroup related information:
1273  */
1274 static int sched_autogroup_show(struct seq_file *m, void *v)
1275 {
1276         struct inode *inode = m->private;
1277         struct task_struct *p;
1278
1279         p = get_proc_task(inode);
1280         if (!p)
1281                 return -ESRCH;
1282         proc_sched_autogroup_show_task(p, m);
1283
1284         put_task_struct(p);
1285
1286         return 0;
1287 }
1288
1289 static ssize_t
1290 sched_autogroup_write(struct file *file, const char __user *buf,
1291             size_t count, loff_t *offset)
1292 {
1293         struct inode *inode = file->f_path.dentry->d_inode;
1294         struct task_struct *p;
1295         char buffer[PROC_NUMBUF];
1296         int nice;
1297         int err;
1298
1299         memset(buffer, 0, sizeof(buffer));
1300         if (count > sizeof(buffer) - 1)
1301                 count = sizeof(buffer) - 1;
1302         if (copy_from_user(buffer, buf, count))
1303                 return -EFAULT;
1304
1305         err = kstrtoint(strstrip(buffer), 0, &nice);
1306         if (err < 0)
1307                 return err;
1308
1309         p = get_proc_task(inode);
1310         if (!p)
1311                 return -ESRCH;
1312
1313         err = proc_sched_autogroup_set_nice(p, nice);
1314         if (err)
1315                 count = err;
1316
1317         put_task_struct(p);
1318
1319         return count;
1320 }
1321
1322 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1323 {
1324         int ret;
1325
1326         ret = single_open(filp, sched_autogroup_show, NULL);
1327         if (!ret) {
1328                 struct seq_file *m = filp->private_data;
1329
1330                 m->private = inode;
1331         }
1332         return ret;
1333 }
1334
1335 static const struct file_operations proc_pid_sched_autogroup_operations = {
1336         .open           = sched_autogroup_open,
1337         .read           = seq_read,
1338         .write          = sched_autogroup_write,
1339         .llseek         = seq_lseek,
1340         .release        = single_release,
1341 };
1342
1343 #endif /* CONFIG_SCHED_AUTOGROUP */
1344
1345 static ssize_t comm_write(struct file *file, const char __user *buf,
1346                                 size_t count, loff_t *offset)
1347 {
1348         struct inode *inode = file->f_path.dentry->d_inode;
1349         struct task_struct *p;
1350         char buffer[TASK_COMM_LEN];
1351
1352         memset(buffer, 0, sizeof(buffer));
1353         if (count > sizeof(buffer) - 1)
1354                 count = sizeof(buffer) - 1;
1355         if (copy_from_user(buffer, buf, count))
1356                 return -EFAULT;
1357
1358         p = get_proc_task(inode);
1359         if (!p)
1360                 return -ESRCH;
1361
1362         if (same_thread_group(current, p))
1363                 set_task_comm(p, buffer);
1364         else
1365                 count = -EINVAL;
1366
1367         put_task_struct(p);
1368
1369         return count;
1370 }
1371
1372 static int comm_show(struct seq_file *m, void *v)
1373 {
1374         struct inode *inode = m->private;
1375         struct task_struct *p;
1376
1377         p = get_proc_task(inode);
1378         if (!p)
1379                 return -ESRCH;
1380
1381         task_lock(p);
1382         seq_printf(m, "%s\n", p->comm);
1383         task_unlock(p);
1384
1385         put_task_struct(p);
1386
1387         return 0;
1388 }
1389
1390 static int comm_open(struct inode *inode, struct file *filp)
1391 {
1392         return single_open(filp, comm_show, inode);
1393 }
1394
1395 static const struct file_operations proc_pid_set_comm_operations = {
1396         .open           = comm_open,
1397         .read           = seq_read,
1398         .write          = comm_write,
1399         .llseek         = seq_lseek,
1400         .release        = single_release,
1401 };
1402
1403 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1404 {
1405         struct task_struct *task;
1406         struct mm_struct *mm;
1407         struct file *exe_file;
1408
1409         task = get_proc_task(dentry->d_inode);
1410         if (!task)
1411                 return -ENOENT;
1412         mm = get_task_mm(task);
1413         put_task_struct(task);
1414         if (!mm)
1415                 return -ENOENT;
1416         exe_file = get_mm_exe_file(mm);
1417         mmput(mm);
1418         if (exe_file) {
1419                 *exe_path = exe_file->f_path;
1420                 path_get(&exe_file->f_path);
1421                 fput(exe_file);
1422                 return 0;
1423         } else
1424                 return -ENOENT;
1425 }
1426
1427 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1428 {
1429         struct inode *inode = dentry->d_inode;
1430         int error = -EACCES;
1431
1432         /* We don't need a base pointer in the /proc filesystem */
1433         path_put(&nd->path);
1434
1435         /* Are we allowed to snoop on the tasks file descriptors? */
1436         if (!proc_fd_access_allowed(inode))
1437                 goto out;
1438
1439         error = PROC_I(inode)->op.proc_get_link(dentry, &nd->path);
1440 out:
1441         return ERR_PTR(error);
1442 }
1443
1444 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1445 {
1446         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1447         char *pathname;
1448         int len;
1449
1450         if (!tmp)
1451                 return -ENOMEM;
1452
1453         pathname = d_path(path, tmp, PAGE_SIZE);
1454         len = PTR_ERR(pathname);
1455         if (IS_ERR(pathname))
1456                 goto out;
1457         len = tmp + PAGE_SIZE - 1 - pathname;
1458
1459         if (len > buflen)
1460                 len = buflen;
1461         if (copy_to_user(buffer, pathname, len))
1462                 len = -EFAULT;
1463  out:
1464         free_page((unsigned long)tmp);
1465         return len;
1466 }
1467
1468 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1469 {
1470         int error = -EACCES;
1471         struct inode *inode = dentry->d_inode;
1472         struct path path;
1473
1474         /* Are we allowed to snoop on the tasks file descriptors? */
1475         if (!proc_fd_access_allowed(inode))
1476                 goto out;
1477
1478         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1479         if (error)
1480                 goto out;
1481
1482         error = do_proc_readlink(&path, buffer, buflen);
1483         path_put(&path);
1484 out:
1485         return error;
1486 }
1487
1488 static const struct inode_operations proc_pid_link_inode_operations = {
1489         .readlink       = proc_pid_readlink,
1490         .follow_link    = proc_pid_follow_link,
1491         .setattr        = proc_setattr,
1492 };
1493
1494
1495 /* building an inode */
1496
1497 static int task_dumpable(struct task_struct *task)
1498 {
1499         int dumpable = 0;
1500         struct mm_struct *mm;
1501
1502         task_lock(task);
1503         mm = task->mm;
1504         if (mm)
1505                 dumpable = get_dumpable(mm);
1506         task_unlock(task);
1507         if(dumpable == 1)
1508                 return 1;
1509         return 0;
1510 }
1511
1512 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1513 {
1514         struct inode * inode;
1515         struct proc_inode *ei;
1516         const struct cred *cred;
1517
1518         /* We need a new inode */
1519
1520         inode = new_inode(sb);
1521         if (!inode)
1522                 goto out;
1523
1524         /* Common stuff */
1525         ei = PROC_I(inode);
1526         inode->i_ino = get_next_ino();
1527         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1528         inode->i_op = &proc_def_inode_operations;
1529
1530         /*
1531          * grab the reference to task.
1532          */
1533         ei->pid = get_task_pid(task, PIDTYPE_PID);
1534         if (!ei->pid)
1535                 goto out_unlock;
1536
1537         if (task_dumpable(task)) {
1538                 rcu_read_lock();
1539                 cred = __task_cred(task);
1540                 inode->i_uid = cred->euid;
1541                 inode->i_gid = cred->egid;
1542                 rcu_read_unlock();
1543         }
1544         security_task_to_inode(task, inode);
1545
1546 out:
1547         return inode;
1548
1549 out_unlock:
1550         iput(inode);
1551         return NULL;
1552 }
1553
1554 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1555 {
1556         struct inode *inode = dentry->d_inode;
1557         struct task_struct *task;
1558         const struct cred *cred;
1559         struct pid_namespace *pid = dentry->d_sb->s_fs_info;
1560
1561         generic_fillattr(inode, stat);
1562
1563         rcu_read_lock();
1564         stat->uid = GLOBAL_ROOT_UID;
1565         stat->gid = GLOBAL_ROOT_GID;
1566         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1567         if (task) {
1568                 if (!has_pid_permissions(pid, task, 2)) {
1569                         rcu_read_unlock();
1570                         /*
1571                          * This doesn't prevent learning whether PID exists,
1572                          * it only makes getattr() consistent with readdir().
1573                          */
1574                         return -ENOENT;
1575                 }
1576                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1577                     task_dumpable(task)) {
1578                         cred = __task_cred(task);
1579                         stat->uid = cred->euid;
1580                         stat->gid = cred->egid;
1581                 }
1582         }
1583         rcu_read_unlock();
1584         return 0;
1585 }
1586
1587 /* dentry stuff */
1588
1589 /*
1590  *      Exceptional case: normally we are not allowed to unhash a busy
1591  * directory. In this case, however, we can do it - no aliasing problems
1592  * due to the way we treat inodes.
1593  *
1594  * Rewrite the inode's ownerships here because the owning task may have
1595  * performed a setuid(), etc.
1596  *
1597  * Before the /proc/pid/status file was created the only way to read
1598  * the effective uid of a /process was to stat /proc/pid.  Reading
1599  * /proc/pid/status is slow enough that procps and other packages
1600  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1601  * made this apply to all per process world readable and executable
1602  * directories.
1603  */
1604 int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1605 {
1606         struct inode *inode;
1607         struct task_struct *task;
1608         const struct cred *cred;
1609
1610         if (nd && nd->flags & LOOKUP_RCU)
1611                 return -ECHILD;
1612
1613         inode = dentry->d_inode;
1614         task = get_proc_task(inode);
1615
1616         if (task) {
1617                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1618                     task_dumpable(task)) {
1619                         rcu_read_lock();
1620                         cred = __task_cred(task);
1621                         inode->i_uid = cred->euid;
1622                         inode->i_gid = cred->egid;
1623                         rcu_read_unlock();
1624                 } else {
1625                         inode->i_uid = GLOBAL_ROOT_UID;
1626                         inode->i_gid = GLOBAL_ROOT_GID;
1627                 }
1628                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1629                 security_task_to_inode(task, inode);
1630                 put_task_struct(task);
1631                 return 1;
1632         }
1633         d_drop(dentry);
1634         return 0;
1635 }
1636
1637 static int pid_delete_dentry(const struct dentry * dentry)
1638 {
1639         /* Is the task we represent dead?
1640          * If so, then don't put the dentry on the lru list,
1641          * kill it immediately.
1642          */
1643         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1644 }
1645
1646 const struct dentry_operations pid_dentry_operations =
1647 {
1648         .d_revalidate   = pid_revalidate,
1649         .d_delete       = pid_delete_dentry,
1650 };
1651
1652 /* Lookups */
1653
1654 /*
1655  * Fill a directory entry.
1656  *
1657  * If possible create the dcache entry and derive our inode number and
1658  * file type from dcache entry.
1659  *
1660  * Since all of the proc inode numbers are dynamically generated, the inode
1661  * numbers do not exist until the inode is cache.  This means creating the
1662  * the dcache entry in readdir is necessary to keep the inode numbers
1663  * reported by readdir in sync with the inode numbers reported
1664  * by stat.
1665  */
1666 int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1667         const char *name, int len,
1668         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1669 {
1670         struct dentry *child, *dir = filp->f_path.dentry;
1671         struct inode *inode;
1672         struct qstr qname;
1673         ino_t ino = 0;
1674         unsigned type = DT_UNKNOWN;
1675
1676         qname.name = name;
1677         qname.len  = len;
1678         qname.hash = full_name_hash(name, len);
1679
1680         child = d_lookup(dir, &qname);
1681         if (!child) {
1682                 struct dentry *new;
1683                 new = d_alloc(dir, &qname);
1684                 if (new) {
1685                         child = instantiate(dir->d_inode, new, task, ptr);
1686                         if (child)
1687                                 dput(new);
1688                         else
1689                                 child = new;
1690                 }
1691         }
1692         if (!child || IS_ERR(child) || !child->d_inode)
1693                 goto end_instantiate;
1694         inode = child->d_inode;
1695         if (inode) {
1696                 ino = inode->i_ino;
1697                 type = inode->i_mode >> 12;
1698         }
1699         dput(child);
1700 end_instantiate:
1701         if (!ino)
1702                 ino = find_inode_number(dir, &qname);
1703         if (!ino)
1704                 ino = 1;
1705         return filldir(dirent, name, len, filp->f_pos, ino, type);
1706 }
1707
1708 static unsigned name_to_int(struct dentry *dentry)
1709 {
1710         const char *name = dentry->d_name.name;
1711         int len = dentry->d_name.len;
1712         unsigned n = 0;
1713
1714         if (len > 1 && *name == '0')
1715                 goto out;
1716         while (len-- > 0) {
1717                 unsigned c = *name++ - '0';
1718                 if (c > 9)
1719                         goto out;
1720                 if (n >= (~0U-9)/10)
1721                         goto out;
1722                 n *= 10;
1723                 n += c;
1724         }
1725         return n;
1726 out:
1727         return ~0U;
1728 }
1729
1730 #define PROC_FDINFO_MAX 64
1731
1732 static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1733 {
1734         struct task_struct *task = get_proc_task(inode);
1735         struct files_struct *files = NULL;
1736         struct file *file;
1737         int fd = proc_fd(inode);
1738
1739         if (task) {
1740                 files = get_files_struct(task);
1741                 put_task_struct(task);
1742         }
1743         if (files) {
1744                 /*
1745                  * We are not taking a ref to the file structure, so we must
1746                  * hold ->file_lock.
1747                  */
1748                 spin_lock(&files->file_lock);
1749                 file = fcheck_files(files, fd);
1750                 if (file) {
1751                         unsigned int f_flags;
1752                         struct fdtable *fdt;
1753
1754                         fdt = files_fdtable(files);
1755                         f_flags = file->f_flags & ~O_CLOEXEC;
1756                         if (close_on_exec(fd, fdt))
1757                                 f_flags |= O_CLOEXEC;
1758
1759                         if (path) {
1760                                 *path = file->f_path;
1761                                 path_get(&file->f_path);
1762                         }
1763                         if (info)
1764                                 snprintf(info, PROC_FDINFO_MAX,
1765                                          "pos:\t%lli\n"
1766                                          "flags:\t0%o\n",
1767                                          (long long) file->f_pos,
1768                                          f_flags);
1769                         spin_unlock(&files->file_lock);
1770                         put_files_struct(files);
1771                         return 0;
1772                 }
1773                 spin_unlock(&files->file_lock);
1774                 put_files_struct(files);
1775         }
1776         return -ENOENT;
1777 }
1778
1779 static int proc_fd_link(struct dentry *dentry, struct path *path)
1780 {
1781         return proc_fd_info(dentry->d_inode, path, NULL);
1782 }
1783
1784 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1785 {
1786         struct inode *inode;
1787         struct task_struct *task;
1788         int fd;
1789         struct files_struct *files;
1790         const struct cred *cred;
1791
1792         if (nd && nd->flags & LOOKUP_RCU)
1793                 return -ECHILD;
1794
1795         inode = dentry->d_inode;
1796         task = get_proc_task(inode);
1797         fd = proc_fd(inode);
1798
1799         if (task) {
1800                 files = get_files_struct(task);
1801                 if (files) {
1802                         struct file *file;
1803                         rcu_read_lock();
1804                         file = fcheck_files(files, fd);
1805                         if (file) {
1806                                 unsigned i_mode, f_mode = file->f_mode;
1807
1808                                 rcu_read_unlock();
1809                                 put_files_struct(files);
1810
1811                                 if (task_dumpable(task)) {
1812                                         rcu_read_lock();
1813                                         cred = __task_cred(task);
1814                                         inode->i_uid = cred->euid;
1815                                         inode->i_gid = cred->egid;
1816                                         rcu_read_unlock();
1817                                 } else {
1818                                         inode->i_uid = GLOBAL_ROOT_UID;
1819                                         inode->i_gid = GLOBAL_ROOT_GID;
1820                                 }
1821
1822                                 i_mode = S_IFLNK;
1823                                 if (f_mode & FMODE_READ)
1824                                         i_mode |= S_IRUSR | S_IXUSR;
1825                                 if (f_mode & FMODE_WRITE)
1826                                         i_mode |= S_IWUSR | S_IXUSR;
1827                                 inode->i_mode = i_mode;
1828
1829                                 security_task_to_inode(task, inode);
1830                                 put_task_struct(task);
1831                                 return 1;
1832                         }
1833                         rcu_read_unlock();
1834                         put_files_struct(files);
1835                 }
1836                 put_task_struct(task);
1837         }
1838         d_drop(dentry);
1839         return 0;
1840 }
1841
1842 static const struct dentry_operations tid_fd_dentry_operations =
1843 {
1844         .d_revalidate   = tid_fd_revalidate,
1845         .d_delete       = pid_delete_dentry,
1846 };
1847
1848 static struct dentry *proc_fd_instantiate(struct inode *dir,
1849         struct dentry *dentry, struct task_struct *task, const void *ptr)
1850 {
1851         unsigned fd = *(const unsigned *)ptr;
1852         struct inode *inode;
1853         struct proc_inode *ei;
1854         struct dentry *error = ERR_PTR(-ENOENT);
1855
1856         inode = proc_pid_make_inode(dir->i_sb, task);
1857         if (!inode)
1858                 goto out;
1859         ei = PROC_I(inode);
1860         ei->fd = fd;
1861
1862         inode->i_op = &proc_pid_link_inode_operations;
1863         inode->i_size = 64;
1864         ei->op.proc_get_link = proc_fd_link;
1865         d_set_d_op(dentry, &tid_fd_dentry_operations);
1866         d_add(dentry, inode);
1867         /* Close the race of the process dying before we return the dentry */
1868         if (tid_fd_revalidate(dentry, NULL))
1869                 error = NULL;
1870
1871  out:
1872         return error;
1873 }
1874
1875 static struct dentry *proc_lookupfd_common(struct inode *dir,
1876                                            struct dentry *dentry,
1877                                            instantiate_t instantiate)
1878 {
1879         struct task_struct *task = get_proc_task(dir);
1880         unsigned fd = name_to_int(dentry);
1881         struct dentry *result = ERR_PTR(-ENOENT);
1882
1883         if (!task)
1884                 goto out_no_task;
1885         if (fd == ~0U)
1886                 goto out;
1887
1888         result = instantiate(dir, dentry, task, &fd);
1889 out:
1890         put_task_struct(task);
1891 out_no_task:
1892         return result;
1893 }
1894
1895 static int proc_readfd_common(struct file * filp, void * dirent,
1896                               filldir_t filldir, instantiate_t instantiate)
1897 {
1898         struct dentry *dentry = filp->f_path.dentry;
1899         struct inode *inode = dentry->d_inode;
1900         struct task_struct *p = get_proc_task(inode);
1901         unsigned int fd, ino;
1902         int retval;
1903         struct files_struct * files;
1904
1905         retval = -ENOENT;
1906         if (!p)
1907                 goto out_no_task;
1908         retval = 0;
1909
1910         fd = filp->f_pos;
1911         switch (fd) {
1912                 case 0:
1913                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1914                                 goto out;
1915                         filp->f_pos++;
1916                 case 1:
1917                         ino = parent_ino(dentry);
1918                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1919                                 goto out;
1920                         filp->f_pos++;
1921                 default:
1922                         files = get_files_struct(p);
1923                         if (!files)
1924                                 goto out;
1925                         rcu_read_lock();
1926                         for (fd = filp->f_pos-2;
1927                              fd < files_fdtable(files)->max_fds;
1928                              fd++, filp->f_pos++) {
1929                                 char name[PROC_NUMBUF];
1930                                 int len;
1931
1932                                 if (!fcheck_files(files, fd))
1933                                         continue;
1934                                 rcu_read_unlock();
1935
1936                                 len = snprintf(name, sizeof(name), "%d", fd);
1937                                 if (proc_fill_cache(filp, dirent, filldir,
1938                                                     name, len, instantiate,
1939                                                     p, &fd) < 0) {
1940                                         rcu_read_lock();
1941                                         break;
1942                                 }
1943                                 rcu_read_lock();
1944                         }
1945                         rcu_read_unlock();
1946                         put_files_struct(files);
1947         }
1948 out:
1949         put_task_struct(p);
1950 out_no_task:
1951         return retval;
1952 }
1953
1954 static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
1955                                     struct nameidata *nd)
1956 {
1957         return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
1958 }
1959
1960 static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
1961 {
1962         return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
1963 }
1964
1965 static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
1966                                       size_t len, loff_t *ppos)
1967 {
1968         char tmp[PROC_FDINFO_MAX];
1969         int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
1970         if (!err)
1971                 err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
1972         return err;
1973 }
1974
1975 static const struct file_operations proc_fdinfo_file_operations = {
1976         .open           = nonseekable_open,
1977         .read           = proc_fdinfo_read,
1978         .llseek         = no_llseek,
1979 };
1980
1981 static const struct file_operations proc_fd_operations = {
1982         .read           = generic_read_dir,
1983         .readdir        = proc_readfd,
1984         .llseek         = default_llseek,
1985 };
1986
1987 #ifdef CONFIG_CHECKPOINT_RESTORE
1988
1989 /*
1990  * dname_to_vma_addr - maps a dentry name into two unsigned longs
1991  * which represent vma start and end addresses.
1992  */
1993 static int dname_to_vma_addr(struct dentry *dentry,
1994                              unsigned long *start, unsigned long *end)
1995 {
1996         if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
1997                 return -EINVAL;
1998
1999         return 0;
2000 }
2001
2002 static int map_files_d_revalidate(struct dentry *dentry, struct nameidata *nd)
2003 {
2004         unsigned long vm_start, vm_end;
2005         bool exact_vma_exists = false;
2006         struct mm_struct *mm = NULL;
2007         struct task_struct *task;
2008         const struct cred *cred;
2009         struct inode *inode;
2010         int status = 0;
2011
2012         if (nd && nd->flags & LOOKUP_RCU)
2013                 return -ECHILD;
2014
2015         if (!capable(CAP_SYS_ADMIN)) {
2016                 status = -EACCES;
2017                 goto out_notask;
2018         }
2019
2020         inode = dentry->d_inode;
2021         task = get_proc_task(inode);
2022         if (!task)
2023                 goto out_notask;
2024
2025         mm = mm_access(task, PTRACE_MODE_READ);
2026         if (IS_ERR_OR_NULL(mm))
2027                 goto out;
2028
2029         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
2030                 down_read(&mm->mmap_sem);
2031                 exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
2032                 up_read(&mm->mmap_sem);
2033         }
2034
2035         mmput(mm);
2036
2037         if (exact_vma_exists) {
2038                 if (task_dumpable(task)) {
2039                         rcu_read_lock();
2040                         cred = __task_cred(task);
2041                         inode->i_uid = cred->euid;
2042                         inode->i_gid = cred->egid;
2043                         rcu_read_unlock();
2044                 } else {
2045                         inode->i_uid = GLOBAL_ROOT_UID;
2046                         inode->i_gid = GLOBAL_ROOT_GID;
2047                 }
2048                 security_task_to_inode(task, inode);
2049                 status = 1;
2050         }
2051
2052 out:
2053         put_task_struct(task);
2054
2055 out_notask:
2056         if (status <= 0)
2057                 d_drop(dentry);
2058
2059         return status;
2060 }
2061
2062 static const struct dentry_operations tid_map_files_dentry_operations = {
2063         .d_revalidate   = map_files_d_revalidate,
2064         .d_delete       = pid_delete_dentry,
2065 };
2066
2067 static int proc_map_files_get_link(struct dentry *dentry, struct path *path)
2068 {
2069         unsigned long vm_start, vm_end;
2070         struct vm_area_struct *vma;
2071         struct task_struct *task;
2072         struct mm_struct *mm;
2073         int rc;
2074
2075         rc = -ENOENT;
2076         task = get_proc_task(dentry->d_inode);
2077         if (!task)
2078                 goto out;
2079
2080         mm = get_task_mm(task);
2081         put_task_struct(task);
2082         if (!mm)
2083                 goto out;
2084
2085         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
2086         if (rc)
2087                 goto out_mmput;
2088
2089         down_read(&mm->mmap_sem);
2090         vma = find_exact_vma(mm, vm_start, vm_end);
2091         if (vma && vma->vm_file) {
2092                 *path = vma->vm_file->f_path;
2093                 path_get(path);
2094                 rc = 0;
2095         }
2096         up_read(&mm->mmap_sem);
2097
2098 out_mmput:
2099         mmput(mm);
2100 out:
2101         return rc;
2102 }
2103
2104 struct map_files_info {
2105         struct file     *file;
2106         unsigned long   len;
2107         unsigned char   name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
2108 };
2109
2110 static struct dentry *
2111 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
2112                            struct task_struct *task, const void *ptr)
2113 {
2114         const struct file *file = ptr;
2115         struct proc_inode *ei;
2116         struct inode *inode;
2117
2118         if (!file)
2119                 return ERR_PTR(-ENOENT);
2120
2121         inode = proc_pid_make_inode(dir->i_sb, task);
2122         if (!inode)
2123                 return ERR_PTR(-ENOENT);
2124
2125         ei = PROC_I(inode);
2126         ei->op.proc_get_link = proc_map_files_get_link;
2127
2128         inode->i_op = &proc_pid_link_inode_operations;
2129         inode->i_size = 64;
2130         inode->i_mode = S_IFLNK;
2131
2132         if (file->f_mode & FMODE_READ)
2133                 inode->i_mode |= S_IRUSR;
2134         if (file->f_mode & FMODE_WRITE)
2135                 inode->i_mode |= S_IWUSR;
2136
2137         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2138         d_add(dentry, inode);
2139
2140         return NULL;
2141 }
2142
2143 static struct dentry *proc_map_files_lookup(struct inode *dir,
2144                 struct dentry *dentry, struct nameidata *nd)
2145 {
2146         unsigned long vm_start, vm_end;
2147         struct vm_area_struct *vma;
2148         struct task_struct *task;
2149         struct dentry *result;
2150         struct mm_struct *mm;
2151
2152         result = ERR_PTR(-EACCES);
2153         if (!capable(CAP_SYS_ADMIN))
2154                 goto out;
2155
2156         result = ERR_PTR(-ENOENT);
2157         task = get_proc_task(dir);
2158         if (!task)
2159                 goto out;
2160
2161         result = ERR_PTR(-EACCES);
2162         if (!ptrace_may_access(task, PTRACE_MODE_READ))
2163                 goto out_put_task;
2164
2165         result = ERR_PTR(-ENOENT);
2166         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2167                 goto out_put_task;
2168
2169         mm = get_task_mm(task);
2170         if (!mm)
2171                 goto out_put_task;
2172
2173         down_read(&mm->mmap_sem);
2174         vma = find_exact_vma(mm, vm_start, vm_end);
2175         if (!vma)
2176                 goto out_no_vma;
2177
2178         result = proc_map_files_instantiate(dir, dentry, task, vma->vm_file);
2179
2180 out_no_vma:
2181         up_read(&mm->mmap_sem);
2182         mmput(mm);
2183 out_put_task:
2184         put_task_struct(task);
2185 out:
2186         return result;
2187 }
2188
2189 static const struct inode_operations proc_map_files_inode_operations = {
2190         .lookup         = proc_map_files_lookup,
2191         .permission     = proc_fd_permission,
2192         .setattr        = proc_setattr,
2193 };
2194
2195 static int
2196 proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
2197 {
2198         struct dentry *dentry = filp->f_path.dentry;
2199         struct inode *inode = dentry->d_inode;
2200         struct vm_area_struct *vma;
2201         struct task_struct *task;
2202         struct mm_struct *mm;
2203         ino_t ino;
2204         int ret;
2205
2206         ret = -EACCES;
2207         if (!capable(CAP_SYS_ADMIN))
2208                 goto out;
2209
2210         ret = -ENOENT;
2211         task = get_proc_task(inode);
2212         if (!task)
2213                 goto out;
2214
2215         ret = -EACCES;
2216         if (!ptrace_may_access(task, PTRACE_MODE_READ))
2217                 goto out_put_task;
2218
2219         ret = 0;
2220         switch (filp->f_pos) {
2221         case 0:
2222                 ino = inode->i_ino;
2223                 if (filldir(dirent, ".", 1, 0, ino, DT_DIR) < 0)
2224                         goto out_put_task;
2225                 filp->f_pos++;
2226         case 1:
2227                 ino = parent_ino(dentry);
2228                 if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
2229                         goto out_put_task;
2230                 filp->f_pos++;
2231         default:
2232         {
2233                 unsigned long nr_files, pos, i;
2234                 struct flex_array *fa = NULL;
2235                 struct map_files_info info;
2236                 struct map_files_info *p;
2237
2238                 mm = get_task_mm(task);
2239                 if (!mm)
2240                         goto out_put_task;
2241                 down_read(&mm->mmap_sem);
2242
2243                 nr_files = 0;
2244
2245                 /*
2246                  * We need two passes here:
2247                  *
2248                  *  1) Collect vmas of mapped files with mmap_sem taken
2249                  *  2) Release mmap_sem and instantiate entries
2250                  *
2251                  * otherwise we get lockdep complained, since filldir()
2252                  * routine might require mmap_sem taken in might_fault().
2253                  */
2254
2255                 for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2256                         if (vma->vm_file && ++pos > filp->f_pos)
2257                                 nr_files++;
2258                 }
2259
2260                 if (nr_files) {
2261                         fa = flex_array_alloc(sizeof(info), nr_files,
2262                                                 GFP_KERNEL);
2263                         if (!fa || flex_array_prealloc(fa, 0, nr_files,
2264                                                         GFP_KERNEL)) {
2265                                 ret = -ENOMEM;
2266                                 if (fa)
2267                                         flex_array_free(fa);
2268                                 up_read(&mm->mmap_sem);
2269                                 mmput(mm);
2270                                 goto out_put_task;
2271                         }
2272                         for (i = 0, vma = mm->mmap, pos = 2; vma;
2273                                         vma = vma->vm_next) {
2274                                 if (!vma->vm_file)
2275                                         continue;
2276                                 if (++pos <= filp->f_pos)
2277                                         continue;
2278
2279                                 get_file(vma->vm_file);
2280                                 info.file = vma->vm_file;
2281                                 info.len = snprintf(info.name,
2282                                                 sizeof(info.name), "%lx-%lx",
2283                                                 vma->vm_start, vma->vm_end);
2284                                 if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2285                                         BUG();
2286                         }
2287                 }
2288                 up_read(&mm->mmap_sem);
2289
2290                 for (i = 0; i < nr_files; i++) {
2291                         p = flex_array_get(fa, i);
2292                         ret = proc_fill_cache(filp, dirent, filldir,
2293                                               p->name, p->len,
2294                                               proc_map_files_instantiate,
2295                                               task, p->file);
2296                         if (ret)
2297                                 break;
2298                         filp->f_pos++;
2299                         fput(p->file);
2300                 }
2301                 for (; i < nr_files; i++) {
2302                         /*
2303                          * In case of error don't forget
2304                          * to put rest of file refs.
2305                          */
2306                         p = flex_array_get(fa, i);
2307                         fput(p->file);
2308                 }
2309                 if (fa)
2310                         flex_array_free(fa);
2311                 mmput(mm);
2312         }
2313         }
2314
2315 out_put_task:
2316         put_task_struct(task);
2317 out:
2318         return ret;
2319 }
2320
2321 static const struct file_operations proc_map_files_operations = {
2322         .read           = generic_read_dir,
2323         .readdir        = proc_map_files_readdir,
2324         .llseek         = default_llseek,
2325 };
2326
2327 #endif /* CONFIG_CHECKPOINT_RESTORE */
2328
2329 /*
2330  * /proc/pid/fd needs a special permission handler so that a process can still
2331  * access /proc/self/fd after it has executed a setuid().
2332  */
2333 static int proc_fd_permission(struct inode *inode, int mask)
2334 {
2335         int rv = generic_permission(inode, mask);
2336         if (rv == 0)
2337                 return 0;
2338         if (task_pid(current) == proc_pid(inode))
2339                 rv = 0;
2340         return rv;
2341 }
2342
2343 /*
2344  * proc directories can do almost nothing..
2345  */
2346 static const struct inode_operations proc_fd_inode_operations = {
2347         .lookup         = proc_lookupfd,
2348         .permission     = proc_fd_permission,
2349         .setattr        = proc_setattr,
2350 };
2351
2352 static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
2353         struct dentry *dentry, struct task_struct *task, const void *ptr)
2354 {
2355         unsigned fd = *(unsigned *)ptr;
2356         struct inode *inode;
2357         struct proc_inode *ei;
2358         struct dentry *error = ERR_PTR(-ENOENT);
2359
2360         inode = proc_pid_make_inode(dir->i_sb, task);
2361         if (!inode)
2362                 goto out;
2363         ei = PROC_I(inode);
2364         ei->fd = fd;
2365         inode->i_mode = S_IFREG | S_IRUSR;
2366         inode->i_fop = &proc_fdinfo_file_operations;
2367         d_set_d_op(dentry, &tid_fd_dentry_operations);
2368         d_add(dentry, inode);
2369         /* Close the race of the process dying before we return the dentry */
2370         if (tid_fd_revalidate(dentry, NULL))
2371                 error = NULL;
2372
2373  out:
2374         return error;
2375 }
2376
2377 static struct dentry *proc_lookupfdinfo(struct inode *dir,
2378                                         struct dentry *dentry,
2379                                         struct nameidata *nd)
2380 {
2381         return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
2382 }
2383
2384 static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
2385 {
2386         return proc_readfd_common(filp, dirent, filldir,
2387                                   proc_fdinfo_instantiate);
2388 }
2389
2390 static const struct file_operations proc_fdinfo_operations = {
2391         .read           = generic_read_dir,
2392         .readdir        = proc_readfdinfo,
2393         .llseek         = default_llseek,
2394 };
2395
2396 /*
2397  * proc directories can do almost nothing..
2398  */
2399 static const struct inode_operations proc_fdinfo_inode_operations = {
2400         .lookup         = proc_lookupfdinfo,
2401         .setattr        = proc_setattr,
2402 };
2403
2404
2405 static struct dentry *proc_pident_instantiate(struct inode *dir,
2406         struct dentry *dentry, struct task_struct *task, const void *ptr)
2407 {
2408         const struct pid_entry *p = ptr;
2409         struct inode *inode;
2410         struct proc_inode *ei;
2411         struct dentry *error = ERR_PTR(-ENOENT);
2412
2413         inode = proc_pid_make_inode(dir->i_sb, task);
2414         if (!inode)
2415                 goto out;
2416
2417         ei = PROC_I(inode);
2418         inode->i_mode = p->mode;
2419         if (S_ISDIR(inode->i_mode))
2420                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2421         if (p->iop)
2422                 inode->i_op = p->iop;
2423         if (p->fop)
2424                 inode->i_fop = p->fop;
2425         ei->op = p->op;
2426         d_set_d_op(dentry, &pid_dentry_operations);
2427         d_add(dentry, inode);
2428         /* Close the race of the process dying before we return the dentry */
2429         if (pid_revalidate(dentry, NULL))
2430                 error = NULL;
2431 out:
2432         return error;
2433 }
2434
2435 static struct dentry *proc_pident_lookup(struct inode *dir,
2436                                          struct dentry *dentry,
2437                                          const struct pid_entry *ents,
2438                                          unsigned int nents)
2439 {
2440         struct dentry *error;
2441         struct task_struct *task = get_proc_task(dir);
2442         const struct pid_entry *p, *last;
2443
2444         error = ERR_PTR(-ENOENT);
2445
2446         if (!task)
2447                 goto out_no_task;
2448
2449         /*
2450          * Yes, it does not scale. And it should not. Don't add
2451          * new entries into /proc/<tgid>/ without very good reasons.
2452          */
2453         last = &ents[nents - 1];
2454         for (p = ents; p <= last; p++) {
2455                 if (p->len != dentry->d_name.len)
2456                         continue;
2457                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2458                         break;
2459         }
2460         if (p > last)
2461                 goto out;
2462
2463         error = proc_pident_instantiate(dir, dentry, task, p);
2464 out:
2465         put_task_struct(task);
2466 out_no_task:
2467         return error;
2468 }
2469
2470 static int proc_pident_fill_cache(struct file *filp, void *dirent,
2471         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2472 {
2473         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2474                                 proc_pident_instantiate, task, p);
2475 }
2476
2477 static int proc_pident_readdir(struct file *filp,
2478                 void *dirent, filldir_t filldir,
2479                 const struct pid_entry *ents, unsigned int nents)
2480 {
2481         int i;
2482         struct dentry *dentry = filp->f_path.dentry;
2483         struct inode *inode = dentry->d_inode;
2484         struct task_struct *task = get_proc_task(inode);
2485         const struct pid_entry *p, *last;
2486         ino_t ino;
2487         int ret;
2488
2489         ret = -ENOENT;
2490         if (!task)
2491                 goto out_no_task;
2492
2493         ret = 0;
2494         i = filp->f_pos;
2495         switch (i) {
2496         case 0:
2497                 ino = inode->i_ino;
2498                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2499                         goto out;
2500                 i++;
2501                 filp->f_pos++;
2502                 /* fall through */
2503         case 1:
2504                 ino = parent_ino(dentry);
2505                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2506                         goto out;
2507                 i++;
2508                 filp->f_pos++;
2509                 /* fall through */
2510         default:
2511                 i -= 2;
2512                 if (i >= nents) {
2513                         ret = 1;
2514                         goto out;
2515                 }
2516                 p = ents + i;
2517                 last = &ents[nents - 1];
2518                 while (p <= last) {
2519                         if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2520                                 goto out;
2521                         filp->f_pos++;
2522                         p++;
2523                 }
2524         }
2525
2526         ret = 1;
2527 out:
2528         put_task_struct(task);
2529 out_no_task:
2530         return ret;
2531 }
2532
2533 #ifdef CONFIG_SECURITY
2534 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2535                                   size_t count, loff_t *ppos)
2536 {
2537         struct inode * inode = file->f_path.dentry->d_inode;
2538         char *p = NULL;
2539         ssize_t length;
2540         struct task_struct *task = get_proc_task(inode);
2541
2542         if (!task)
2543                 return -ESRCH;
2544
2545         length = security_getprocattr(task,
2546                                       (char*)file->f_path.dentry->d_name.name,
2547                                       &p);
2548         put_task_struct(task);
2549         if (length > 0)
2550                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2551         kfree(p);
2552         return length;
2553 }
2554
2555 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2556                                    size_t count, loff_t *ppos)
2557 {
2558         struct inode * inode = file->f_path.dentry->d_inode;
2559         char *page;
2560         ssize_t length;
2561         struct task_struct *task = get_proc_task(inode);
2562
2563         length = -ESRCH;
2564         if (!task)
2565                 goto out_no_task;
2566         if (count > PAGE_SIZE)
2567                 count = PAGE_SIZE;
2568
2569         /* No partial writes. */
2570         length = -EINVAL;
2571         if (*ppos != 0)
2572                 goto out;
2573
2574         length = -ENOMEM;
2575         page = (char*)__get_free_page(GFP_TEMPORARY);
2576         if (!page)
2577                 goto out;
2578
2579         length = -EFAULT;
2580         if (copy_from_user(page, buf, count))
2581                 goto out_free;
2582
2583         /* Guard against adverse ptrace interaction */
2584         length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2585         if (length < 0)
2586                 goto out_free;
2587
2588         length = security_setprocattr(task,
2589                                       (char*)file->f_path.dentry->d_name.name,
2590                                       (void*)page, count);
2591         mutex_unlock(&task->signal->cred_guard_mutex);
2592 out_free:
2593         free_page((unsigned long) page);
2594 out:
2595         put_task_struct(task);
2596 out_no_task:
2597         return length;
2598 }
2599
2600 static const struct file_operations proc_pid_attr_operations = {
2601         .read           = proc_pid_attr_read,
2602         .write          = proc_pid_attr_write,
2603         .llseek         = generic_file_llseek,
2604 };
2605
2606 static const struct pid_entry attr_dir_stuff[] = {
2607         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2608         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2609         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2610         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2611         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2612         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2613 };
2614
2615 static int proc_attr_dir_readdir(struct file * filp,
2616                              void * dirent, filldir_t filldir)
2617 {
2618         return proc_pident_readdir(filp,dirent,filldir,
2619                                    attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2620 }
2621
2622 static const struct file_operations proc_attr_dir_operations = {
2623         .read           = generic_read_dir,
2624         .readdir        = proc_attr_dir_readdir,
2625         .llseek         = default_llseek,
2626 };
2627
2628 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2629                                 struct dentry *dentry, struct nameidata *nd)
2630 {
2631         return proc_pident_lookup(dir, dentry,
2632                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2633 }
2634
2635 static const struct inode_operations proc_attr_dir_inode_operations = {
2636         .lookup         = proc_attr_dir_lookup,
2637         .getattr        = pid_getattr,
2638         .setattr        = proc_setattr,
2639 };
2640
2641 #endif
2642
2643 #ifdef CONFIG_ELF_CORE
2644 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2645                                          size_t count, loff_t *ppos)
2646 {
2647         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2648         struct mm_struct *mm;
2649         char buffer[PROC_NUMBUF];
2650         size_t len;
2651         int ret;
2652
2653         if (!task)
2654                 return -ESRCH;
2655
2656         ret = 0;
2657         mm = get_task_mm(task);
2658         if (mm) {
2659                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2660                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2661                                 MMF_DUMP_FILTER_SHIFT));
2662                 mmput(mm);
2663                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2664         }
2665
2666         put_task_struct(task);
2667
2668         return ret;
2669 }
2670
2671 static ssize_t proc_coredump_filter_write(struct file *file,
2672                                           const char __user *buf,
2673                                           size_t count,
2674                                           loff_t *ppos)
2675 {
2676         struct task_struct *task;
2677         struct mm_struct *mm;
2678         char buffer[PROC_NUMBUF], *end;
2679         unsigned int val;
2680         int ret;
2681         int i;
2682         unsigned long mask;
2683
2684         ret = -EFAULT;
2685         memset(buffer, 0, sizeof(buffer));
2686         if (count > sizeof(buffer) - 1)
2687                 count = sizeof(buffer) - 1;
2688         if (copy_from_user(buffer, buf, count))
2689                 goto out_no_task;
2690
2691         ret = -EINVAL;
2692         val = (unsigned int)simple_strtoul(buffer, &end, 0);
2693         if (*end == '\n')
2694                 end++;
2695         if (end - buffer == 0)
2696                 goto out_no_task;
2697
2698         ret = -ESRCH;
2699         task = get_proc_task(file->f_dentry->d_inode);
2700         if (!task)
2701                 goto out_no_task;
2702
2703         ret = end - buffer;
2704         mm = get_task_mm(task);
2705         if (!mm)
2706                 goto out_no_mm;
2707
2708         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2709                 if (val & mask)
2710                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2711                 else
2712                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2713         }
2714
2715         mmput(mm);
2716  out_no_mm:
2717         put_task_struct(task);
2718  out_no_task:
2719         return ret;
2720 }
2721
2722 static const struct file_operations proc_coredump_filter_operations = {
2723         .read           = proc_coredump_filter_read,
2724         .write          = proc_coredump_filter_write,
2725         .llseek         = generic_file_llseek,
2726 };
2727 #endif
2728
2729 /*
2730  * /proc/self:
2731  */
2732 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2733                               int buflen)
2734 {
2735         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2736         pid_t tgid = task_tgid_nr_ns(current, ns);
2737         char tmp[PROC_NUMBUF];
2738         if (!tgid)
2739                 return -ENOENT;
2740         sprintf(tmp, "%d", tgid);
2741         return vfs_readlink(dentry,buffer,buflen,tmp);
2742 }
2743
2744 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2745 {
2746         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2747         pid_t tgid = task_tgid_nr_ns(current, ns);
2748         char *name = ERR_PTR(-ENOENT);
2749         if (tgid) {
2750                 name = __getname();
2751                 if (!name)
2752                         name = ERR_PTR(-ENOMEM);
2753                 else
2754                         sprintf(name, "%d", tgid);
2755         }
2756         nd_set_link(nd, name);
2757         return NULL;
2758 }
2759
2760 static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
2761                                 void *cookie)
2762 {
2763         char *s = nd_get_link(nd);
2764         if (!IS_ERR(s))
2765                 __putname(s);
2766 }
2767
2768 static const struct inode_operations proc_self_inode_operations = {
2769         .readlink       = proc_self_readlink,
2770         .follow_link    = proc_self_follow_link,
2771         .put_link       = proc_self_put_link,
2772 };
2773
2774 /*
2775  * proc base
2776  *
2777  * These are the directory entries in the root directory of /proc
2778  * that properly belong to the /proc filesystem, as they describe
2779  * describe something that is process related.
2780  */
2781 static const struct pid_entry proc_base_stuff[] = {
2782         NOD("self", S_IFLNK|S_IRWXUGO,
2783                 &proc_self_inode_operations, NULL, {}),
2784 };
2785
2786 static struct dentry *proc_base_instantiate(struct inode *dir,
2787         struct dentry *dentry, struct task_struct *task, const void *ptr)
2788 {
2789         const struct pid_entry *p = ptr;
2790         struct inode *inode;
2791         struct proc_inode *ei;
2792         struct dentry *error;
2793
2794         /* Allocate the inode */
2795         error = ERR_PTR(-ENOMEM);
2796         inode = new_inode(dir->i_sb);
2797         if (!inode)
2798                 goto out;
2799
2800         /* Initialize the inode */
2801         ei = PROC_I(inode);
2802         inode->i_ino = get_next_ino();
2803         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2804
2805         /*
2806          * grab the reference to the task.
2807          */
2808         ei->pid = get_task_pid(task, PIDTYPE_PID);
2809         if (!ei->pid)
2810                 goto out_iput;
2811
2812         inode->i_mode = p->mode;
2813         if (S_ISDIR(inode->i_mode))
2814                 set_nlink(inode, 2);
2815         if (S_ISLNK(inode->i_mode))
2816                 inode->i_size = 64;
2817         if (p->iop)
2818                 inode->i_op = p->iop;
2819         if (p->fop)
2820                 inode->i_fop = p->fop;
2821         ei->op = p->op;
2822         d_add(dentry, inode);
2823         error = NULL;
2824 out:
2825         return error;
2826 out_iput:
2827         iput(inode);
2828         goto out;
2829 }
2830
2831 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2832 {
2833         struct dentry *error;
2834         struct task_struct *task = get_proc_task(dir);
2835         const struct pid_entry *p, *last;
2836
2837         error = ERR_PTR(-ENOENT);
2838
2839         if (!task)
2840                 goto out_no_task;
2841
2842         /* Lookup the directory entry */
2843         last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2844         for (p = proc_base_stuff; p <= last; p++) {
2845                 if (p->len != dentry->d_name.len)
2846                         continue;
2847                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2848                         break;
2849         }
2850         if (p > last)
2851                 goto out;
2852
2853         error = proc_base_instantiate(dir, dentry, task, p);
2854
2855 out:
2856         put_task_struct(task);
2857 out_no_task:
2858         return error;
2859 }
2860
2861 static int proc_base_fill_cache(struct file *filp, void *dirent,
2862         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2863 {
2864         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2865                                 proc_base_instantiate, task, p);
2866 }
2867
2868 #ifdef CONFIG_TASK_IO_ACCOUNTING
2869 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2870 {
2871         struct task_io_accounting acct = task->ioac;
2872         unsigned long flags;
2873         int result;
2874
2875         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2876         if (result)
2877                 return result;
2878
2879         if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
2880                 result = -EACCES;
2881                 goto out_unlock;
2882         }
2883
2884         if (whole && lock_task_sighand(task, &flags)) {
2885                 struct task_struct *t = task;
2886
2887                 task_io_accounting_add(&acct, &task->signal->ioac);
2888                 while_each_thread(task, t)
2889                         task_io_accounting_add(&acct, &t->ioac);
2890
2891                 unlock_task_sighand(task, &flags);
2892         }
2893         result = sprintf(buffer,
2894                         "rchar: %llu\n"
2895                         "wchar: %llu\n"
2896                         "syscr: %llu\n"
2897                         "syscw: %llu\n"
2898                         "read_bytes: %llu\n"
2899                         "write_bytes: %llu\n"
2900                         "cancelled_write_bytes: %llu\n",
2901                         (unsigned long long)acct.rchar,
2902                         (unsigned long long)acct.wchar,
2903                         (unsigned long long)acct.syscr,
2904                         (unsigned long long)acct.syscw,
2905                         (unsigned long long)acct.read_bytes,
2906                         (unsigned long long)acct.write_bytes,
2907                         (unsigned long long)acct.cancelled_write_bytes);
2908 out_unlock:
2909         mutex_unlock(&task->signal->cred_guard_mutex);
2910         return result;
2911 }
2912
2913 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2914 {
2915         return do_io_accounting(task, buffer, 0);
2916 }
2917
2918 static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2919 {
2920         return do_io_accounting(task, buffer, 1);
2921 }
2922 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2923
2924 #ifdef CONFIG_USER_NS
2925 static int proc_id_map_open(struct inode *inode, struct file *file,
2926         struct seq_operations *seq_ops)
2927 {
2928         struct user_namespace *ns = NULL;
2929         struct task_struct *task;
2930         struct seq_file *seq;
2931         int ret = -EINVAL;
2932
2933         task = get_proc_task(inode);
2934         if (task) {
2935                 rcu_read_lock();
2936                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2937                 rcu_read_unlock();
2938                 put_task_struct(task);
2939         }
2940         if (!ns)
2941                 goto err;
2942
2943         ret = seq_open(file, seq_ops);
2944         if (ret)
2945                 goto err_put_ns;
2946
2947         seq = file->private_data;
2948         seq->private = ns;
2949
2950         return 0;
2951 err_put_ns:
2952         put_user_ns(ns);
2953 err:
2954         return ret;
2955 }
2956
2957 static int proc_id_map_release(struct inode *inode, struct file *file)
2958 {
2959         struct seq_file *seq = file->private_data;
2960         struct user_namespace *ns = seq->private;
2961         put_user_ns(ns);
2962         return seq_release(inode, file);
2963 }
2964
2965 static int proc_uid_map_open(struct inode *inode, struct file *file)
2966 {
2967         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2968 }
2969
2970 static int proc_gid_map_open(struct inode *inode, struct file *file)
2971 {
2972         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2973 }
2974
2975 static const struct file_operations proc_uid_map_operations = {
2976         .open           = proc_uid_map_open,
2977         .write          = proc_uid_map_write,
2978         .read           = seq_read,
2979         .llseek         = seq_lseek,
2980         .release        = proc_id_map_release,
2981 };
2982
2983 static const struct file_operations proc_gid_map_operations = {
2984         .open           = proc_gid_map_open,
2985         .write          = proc_gid_map_write,
2986         .read           = seq_read,
2987         .llseek         = seq_lseek,
2988         .release        = proc_id_map_release,
2989 };
2990 #endif /* CONFIG_USER_NS */
2991
2992 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2993                                 struct pid *pid, struct task_struct *task)
2994 {
2995         int err = lock_trace(task);
2996         if (!err) {
2997                 seq_printf(m, "%08x\n", task->personality);
2998                 unlock_trace(task);
2999         }
3000         return err;
3001 }
3002
3003 /*
3004  * Thread groups
3005  */
3006 static const struct file_operations proc_task_operations;
3007 static const struct inode_operations proc_task_inode_operations;
3008
3009 static const struct pid_entry tgid_base_stuff[] = {
3010         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
3011         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3012 #ifdef CONFIG_CHECKPOINT_RESTORE
3013         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
3014 #endif
3015         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3016         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3017 #ifdef CONFIG_NET
3018         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3019 #endif
3020         REG("environ",    S_IRUSR, proc_environ_operations),
3021         INF("auxv",       S_IRUSR, proc_pid_auxv),
3022         ONE("status",     S_IRUGO, proc_pid_status),
3023         ONE("personality", S_IRUGO, proc_pid_personality),
3024         INF("limits",     S_IRUGO, proc_pid_limits),
3025 #ifdef CONFIG_SCHED_DEBUG
3026         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3027 #endif
3028 #ifdef CONFIG_SCHED_AUTOGROUP
3029         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
3030 #endif
3031         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3032 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3033         INF("syscall",    S_IRUGO, proc_pid_syscall),
3034 #endif
3035         INF("cmdline",    S_IRUGO, proc_pid_cmdline),
3036         ONE("stat",       S_IRUGO, proc_tgid_stat),
3037         ONE("statm",      S_IRUGO, proc_pid_statm),
3038         REG("maps",       S_IRUGO, proc_pid_maps_operations),
3039 #ifdef CONFIG_NUMA
3040         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
3041 #endif
3042         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
3043         LNK("cwd",        proc_cwd_link),
3044         LNK("root",       proc_root_link),
3045         LNK("exe",        proc_exe_link),
3046         REG("mounts",     S_IRUGO, proc_mounts_operations),
3047         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3048         REG("mountstats", S_IRUSR, proc_mountstats_operations),
3049 #ifdef CONFIG_PROC_PAGE_MONITOR
3050         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3051         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
3052         REG("pagemap",    S_IRUGO, proc_pagemap_operations),
3053 #endif
3054 #ifdef CONFIG_SECURITY
3055         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3056 #endif
3057 #ifdef CONFIG_KALLSYMS
3058         INF("wchan",      S_IRUGO, proc_pid_wchan),
3059 #endif
3060 #ifdef CONFIG_STACKTRACE
3061         ONE("stack",      S_IRUGO, proc_pid_stack),
3062 #endif
3063 #ifdef CONFIG_SCHEDSTATS
3064         INF("schedstat",  S_IRUGO, proc_pid_schedstat),
3065 #endif
3066 #ifdef CONFIG_LATENCYTOP
3067         REG("latency",  S_IRUGO, proc_lstats_operations),
3068 #endif
3069 #ifdef CONFIG_PROC_PID_CPUSET
3070         REG("cpuset",     S_IRUGO, proc_cpuset_operations),
3071 #endif
3072 #ifdef CONFIG_CGROUPS
3073         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3074 #endif
3075         INF("oom_score",  S_IRUGO, proc_oom_score),
3076         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
3077         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3078 #ifdef CONFIG_AUDITSYSCALL
3079         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
3080         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3081 #endif
3082 #ifdef CONFIG_FAULT_INJECTION
3083         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3084 #endif
3085 #ifdef CONFIG_ELF_CORE
3086         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
3087 #endif
3088 #ifdef CONFIG_TASK_IO_ACCOUNTING
3089         INF("io",       S_IRUSR, proc_tgid_io_accounting),
3090 #endif
3091 #ifdef CONFIG_HARDWALL
3092         INF("hardwall",   S_IRUGO, proc_pid_hardwall),
3093 #endif
3094 #ifdef CONFIG_USER_NS
3095         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3096         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3097 #endif
3098 };
3099
3100 static int proc_tgid_base_readdir(struct file * filp,
3101                              void * dirent, filldir_t filldir)
3102 {
3103         return proc_pident_readdir(filp,dirent,filldir,
3104                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
3105 }
3106
3107 static const struct file_operations proc_tgid_base_operations = {
3108         .read           = generic_read_dir,
3109         .readdir        = proc_tgid_base_readdir,
3110         .llseek         = default_llseek,
3111 };
3112
3113 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
3114         return proc_pident_lookup(dir, dentry,
3115                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3116 }
3117
3118 static const struct inode_operations proc_tgid_base_inode_operations = {
3119         .lookup         = proc_tgid_base_lookup,
3120         .getattr        = pid_getattr,
3121         .setattr        = proc_setattr,
3122         .permission     = proc_pid_permission,
3123 };
3124
3125 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
3126 {
3127         struct dentry *dentry, *leader, *dir;
3128         char buf[PROC_NUMBUF];
3129         struct qstr name;
3130
3131         name.name = buf;
3132         name.len = snprintf(buf, sizeof(buf), "%d", pid);
3133         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
3134         if (dentry) {
3135                 shrink_dcache_parent(dentry);
3136                 d_drop(dentry);
3137                 dput(dentry);
3138         }
3139
3140         name.name = buf;
3141         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
3142         leader = d_hash_and_lookup(mnt->mnt_root, &name);
3143         if (!leader)
3144                 goto out;
3145
3146         name.name = "task";
3147         name.len = strlen(name.name);
3148         dir = d_hash_and_lookup(leader, &name);
3149         if (!dir)
3150                 goto out_put_leader;
3151
3152         name.name = buf;
3153         name.len = snprintf(buf, sizeof(buf), "%d", pid);
3154         dentry = d_hash_and_lookup(dir, &name);
3155         if (dentry) {
3156                 shrink_dcache_parent(dentry);
3157                 d_drop(dentry);
3158                 dput(dentry);
3159         }
3160
3161         dput(dir);
3162 out_put_leader:
3163         dput(leader);
3164 out:
3165         return;
3166 }
3167
3168 /**
3169  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
3170  * @task: task that should be flushed.
3171  *
3172  * When flushing dentries from proc, one needs to flush them from global
3173  * proc (proc_mnt) and from all the namespaces' procs this task was seen
3174  * in. This call is supposed to do all of this job.
3175  *
3176  * Looks in the dcache for
3177  * /proc/@pid
3178  * /proc/@tgid/task/@pid
3179  * if either directory is present flushes it and all of it'ts children
3180  * from the dcache.
3181  *
3182  * It is safe and reasonable to cache /proc entries for a task until
3183  * that task exits.  After that they just clog up the dcache with
3184  * useless entries, possibly causing useful dcache entries to be
3185  * flushed instead.  This routine is proved to flush those useless
3186  * dcache entries at process exit time.
3187  *
3188  * NOTE: This routine is just an optimization so it does not guarantee
3189  *       that no dcache entries will exist at process exit time it
3190  *       just makes it very unlikely that any will persist.
3191  */
3192
3193 void proc_flush_task(struct task_struct *task)
3194 {
3195         int i;
3196         struct pid *pid, *tgid;
3197         struct upid *upid;
3198
3199         pid = task_pid(task);
3200         tgid = task_tgid(task);
3201
3202         for (i = 0; i <= pid->level; i++) {
3203                 upid = &pid->numbers[i];
3204                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3205                                         tgid->numbers[i].nr);
3206         }
3207
3208         upid = &pid->numbers[pid->level];
3209         if (upid->nr == 1)
3210                 pid_ns_release_proc(upid->ns);
3211 }
3212
3213 static struct dentry *proc_pid_instantiate(struct inode *dir,
3214                                            struct dentry * dentry,
3215                                            struct task_struct *task, const void *ptr)
3216 {
3217         struct dentry *error = ERR_PTR(-ENOENT);
3218         struct inode *inode;
3219
3220         inode = proc_pid_make_inode(dir->i_sb, task);
3221         if (!inode)
3222                 goto out;
3223
3224         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3225         inode->i_op = &proc_tgid_base_inode_operations;
3226         inode->i_fop = &proc_tgid_base_operations;
3227         inode->i_flags|=S_IMMUTABLE;
3228
3229         set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
3230                                                   ARRAY_SIZE(tgid_base_stuff)));
3231
3232         d_set_d_op(dentry, &pid_dentry_operations);
3233
3234         d_add(dentry, inode);
3235         /* Close the race of the process dying before we return the dentry */
3236         if (pid_revalidate(dentry, NULL))
3237                 error = NULL;
3238 out:
3239         return error;
3240 }
3241
3242 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3243 {
3244         struct dentry *result;
3245         struct task_struct *task;
3246         unsigned tgid;
3247         struct pid_namespace *ns;
3248
3249         result = proc_base_lookup(dir, dentry);
3250         if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
3251                 goto out;
3252
3253         tgid = name_to_int(dentry);
3254         if (tgid == ~0U)
3255                 goto out;
3256
3257         ns = dentry->d_sb->s_fs_info;
3258         rcu_read_lock();
3259         task = find_task_by_pid_ns(tgid, ns);
3260         if (task)
3261                 get_task_struct(task);
3262         rcu_read_unlock();
3263         if (!task)
3264                 goto out;
3265
3266         result = proc_pid_instantiate(dir, dentry, task, NULL);
3267         put_task_struct(task);
3268 out:
3269         return result;
3270 }
3271
3272 /*
3273  * Find the first task with tgid >= tgid
3274  *
3275  */
3276 struct tgid_iter {
3277         unsigned int tgid;
3278         struct task_struct *task;
3279 };
3280 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3281 {
3282         struct pid *pid;
3283
3284         if (iter.task)
3285                 put_task_struct(iter.task);
3286         rcu_read_lock();
3287 retry:
3288         iter.task = NULL;
3289         pid = find_ge_pid(iter.tgid, ns);
3290         if (pid) {
3291                 iter.tgid = pid_nr_ns(pid, ns);
3292                 iter.task = pid_task(pid, PIDTYPE_PID);
3293                 /* What we to know is if the pid we have find is the
3294                  * pid of a thread_group_leader.  Testing for task
3295                  * being a thread_group_leader is the obvious thing
3296                  * todo but there is a window when it fails, due to
3297                  * the pid transfer logic in de_thread.
3298                  *
3299                  * So we perform the straight forward test of seeing
3300                  * if the pid we have found is the pid of a thread
3301                  * group leader, and don't worry if the task we have
3302                  * found doesn't happen to be a thread group leader.
3303                  * As we don't care in the case of readdir.
3304                  */
3305                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3306                         iter.tgid += 1;
3307                         goto retry;
3308                 }
3309                 get_task_struct(iter.task);
3310         }
3311         rcu_read_unlock();
3312         return iter;
3313 }
3314
3315 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
3316
3317 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3318         struct tgid_iter iter)
3319 {
3320         char name[PROC_NUMBUF];
3321         int len = snprintf(name, sizeof(name), "%d", iter.tgid);
3322         return proc_fill_cache(filp, dirent, filldir, name, len,
3323                                 proc_pid_instantiate, iter.task, NULL);
3324 }
3325
3326 static int fake_filldir(void *buf, const char *name, int namelen,
3327                         loff_t offset, u64 ino, unsigned d_type)
3328 {
3329         return 0;
3330 }
3331
3332 /* for the /proc/ directory itself, after non-process stuff has been done */
3333 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
3334 {
3335         unsigned int nr;
3336         struct task_struct *reaper;
3337         struct tgid_iter iter;
3338         struct pid_namespace *ns;
3339         filldir_t __filldir;
3340
3341         if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
3342                 goto out_no_task;
3343         nr = filp->f_pos - FIRST_PROCESS_ENTRY;
3344
3345         reaper = get_proc_task(filp->f_path.dentry->d_inode);
3346         if (!reaper)
3347                 goto out_no_task;
3348
3349         for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
3350                 const struct pid_entry *p = &proc_base_stuff[nr];
3351                 if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
3352                         goto out;
3353         }
3354
3355         ns = filp->f_dentry->d_sb->s_fs_info;
3356         iter.task = NULL;
3357         iter.tgid = filp->f_pos - TGID_OFFSET;
3358         for (iter = next_tgid(ns, iter);
3359              iter.task;
3360              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3361                 if (has_pid_permissions(ns, iter.task, 2))
3362                         __filldir = filldir;
3363                 else
3364                         __filldir = fake_filldir;
3365
3366                 filp->f_pos = iter.tgid + TGID_OFFSET;
3367                 if (proc_pid_fill_cache(filp, dirent, __filldir, iter) < 0) {
3368                         put_task_struct(iter.task);
3369                         goto out;
3370                 }
3371         }
3372         filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
3373 out:
3374         put_task_struct(reaper);
3375 out_no_task:
3376         return 0;
3377 }
3378
3379 /*
3380  * Tasks
3381  */
3382 static const struct pid_entry tid_base_stuff[] = {
3383         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3384         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3385         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3386         REG("environ",   S_IRUSR, proc_environ_operations),
3387         INF("auxv",      S_IRUSR, proc_pid_auxv),
3388         ONE("status",    S_IRUGO, proc_pid_status),
3389         ONE("personality", S_IRUGO, proc_pid_personality),
3390         INF("limits",    S_IRUGO, proc_pid_limits),
3391 #ifdef CONFIG_SCHED_DEBUG
3392         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3393 #endif
3394         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3395 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3396         INF("syscall",   S_IRUGO, proc_pid_syscall),
3397 #endif
3398         INF("cmdline",   S_IRUGO, proc_pid_cmdline),
3399         ONE("stat",      S_IRUGO, proc_tid_stat),
3400         ONE("statm",     S_IRUGO, proc_pid_statm),
3401         REG("maps",      S_IRUGO, proc_tid_maps_operations),
3402 #ifdef CONFIG_NUMA
3403         REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3404 #endif
3405         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3406         LNK("cwd",       proc_cwd_link),
3407         LNK("root",      proc_root_link),
3408         LNK("exe",       proc_exe_link),
3409         REG("mounts",    S_IRUGO, proc_mounts_operations),
3410         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3411 #ifdef CONFIG_PROC_PAGE_MONITOR
3412         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3413         REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3414         REG("pagemap",    S_IRUGO, proc_pagemap_operations),
3415 #endif
3416 #ifdef CONFIG_SECURITY
3417         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3418 #endif
3419 #ifdef CONFIG_KALLSYMS
3420         INF("wchan",     S_IRUGO, proc_pid_wchan),
3421 #endif
3422 #ifdef CONFIG_STACKTRACE
3423         ONE("stack",      S_IRUGO, proc_pid_stack),
3424 #endif
3425 #ifdef CONFIG_SCHEDSTATS
3426         INF("schedstat", S_IRUGO, proc_pid_schedstat),
3427 #endif
3428 #ifdef CONFIG_LATENCYTOP
3429         REG("latency",  S_IRUGO, proc_lstats_operations),
3430 #endif
3431 #ifdef CONFIG_PROC_PID_CPUSET
3432         REG("cpuset",    S_IRUGO, proc_cpuset_operations),
3433 #endif
3434 #ifdef CONFIG_CGROUPS
3435         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3436 #endif
3437         INF("oom_score", S_IRUGO, proc_oom_score),
3438         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
3439         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3440 #ifdef CONFIG_AUDITSYSCALL
3441         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3442         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3443 #endif
3444 #ifdef CONFIG_FAULT_INJECTION
3445         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3446 #endif
3447 #ifdef CONFIG_TASK_IO_ACCOUNTING
3448         INF("io",       S_IRUSR, proc_tid_io_accounting),
3449 #endif
3450 #ifdef CONFIG_HARDWALL
3451         INF("hardwall",   S_IRUGO, proc_pid_hardwall),
3452 #endif
3453 #ifdef CONFIG_USER_NS
3454         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3455         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3456 #endif
3457 };
3458
3459 static int proc_tid_base_readdir(struct file * filp,
3460                              void * dirent, filldir_t filldir)
3461 {
3462         return proc_pident_readdir(filp,dirent,filldir,
3463                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
3464 }
3465
3466 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
3467         return proc_pident_lookup(dir, dentry,
3468                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3469 }
3470
3471 static const struct file_operations proc_tid_base_operations = {
3472         .read           = generic_read_dir,
3473         .readdir        = proc_tid_base_readdir,
3474         .llseek         = default_llseek,
3475 };
3476
3477 static const struct inode_operations proc_tid_base_inode_operations = {
3478         .lookup         = proc_tid_base_lookup,
3479         .getattr        = pid_getattr,
3480         .setattr        = proc_setattr,
3481 };
3482
3483 static struct dentry *proc_task_instantiate(struct inode *dir,
3484         struct dentry *dentry, struct task_struct *task, const void *ptr)
3485 {
3486         struct dentry *error = ERR_PTR(-ENOENT);
3487         struct inode *inode;
3488         inode = proc_pid_make_inode(dir->i_sb, task);
3489
3490         if (!inode)
3491                 goto out;
3492         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3493         inode->i_op = &proc_tid_base_inode_operations;
3494         inode->i_fop = &proc_tid_base_operations;
3495         inode->i_flags|=S_IMMUTABLE;
3496
3497         set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
3498                                                   ARRAY_SIZE(tid_base_stuff)));
3499
3500         d_set_d_op(dentry, &pid_dentry_operations);
3501
3502         d_add(dentry, inode);
3503         /* Close the race of the process dying before we return the dentry */
3504         if (pid_revalidate(dentry, NULL))
3505                 error = NULL;
3506 out:
3507         return error;
3508 }
3509
3510 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3511 {
3512         struct dentry *result = ERR_PTR(-ENOENT);
3513         struct task_struct *task;
3514         struct task_struct *leader = get_proc_task(dir);
3515         unsigned tid;
3516         struct pid_namespace *ns;
3517
3518         if (!leader)
3519                 goto out_no_task;
3520
3521         tid = name_to_int(dentry);
3522         if (tid == ~0U)
3523                 goto out;
3524
3525         ns = dentry->d_sb->s_fs_info;
3526         rcu_read_lock();
3527         task = find_task_by_pid_ns(tid, ns);
3528         if (task)
3529                 get_task_struct(task);
3530         rcu_read_unlock();
3531         if (!task)
3532                 goto out;
3533         if (!same_thread_group(leader, task))
3534                 goto out_drop_task;
3535
3536         result = proc_task_instantiate(dir, dentry, task, NULL);
3537 out_drop_task:
3538         put_task_struct(task);
3539 out:
3540         put_task_struct(leader);
3541 out_no_task:
3542         return result;
3543 }
3544
3545 /*
3546  * Find the first tid of a thread group to return to user space.
3547  *
3548  * Usually this is just the thread group leader, but if the users
3549  * buffer was too small or there was a seek into the middle of the
3550  * directory we have more work todo.
3551  *
3552  * In the case of a short read we start with find_task_by_pid.
3553  *
3554  * In the case of a seek we start with the leader and walk nr
3555  * threads past it.
3556  */
3557 static struct task_struct *first_tid(struct task_struct *leader,
3558                 int tid, int nr, struct pid_namespace *ns)
3559 {
3560         struct task_struct *pos;
3561
3562         rcu_read_lock();
3563         /* Attempt to start with the pid of a thread */
3564         if (tid && (nr > 0)) {
3565                 pos = find_task_by_pid_ns(tid, ns);
3566                 if (pos && (pos->group_leader == leader))
3567                         goto found;
3568         }
3569
3570         /* If nr exceeds the number of threads there is nothing todo */
3571         pos = NULL;
3572         if (nr && nr >= get_nr_threads(leader))
3573                 goto out;
3574
3575         /* If we haven't found our starting place yet start
3576          * with the leader and walk nr threads forward.
3577          */
3578         for (pos = leader; nr > 0; --nr) {
3579                 pos = next_thread(pos);
3580                 if (pos == leader) {
3581                         pos = NULL;
3582                         goto out;
3583                 }
3584         }
3585 found:
3586         get_task_struct(pos);
3587 out:
3588         rcu_read_unlock();
3589         return pos;
3590 }
3591
3592 /*
3593  * Find the next thread in the thread list.
3594  * Return NULL if there is an error or no next thread.
3595  *
3596  * The reference to the input task_struct is released.
3597  */
3598 static struct task_struct *next_tid(struct task_struct *start)
3599 {
3600         struct task_struct *pos = NULL;
3601         rcu_read_lock();
3602         if (pid_alive(start)) {
3603                 pos = next_thread(start);
3604                 if (thread_group_leader(pos))
3605                         pos = NULL;
3606                 else
3607                         get_task_struct(pos);
3608         }
3609         rcu_read_unlock();
3610         put_task_struct(start);
3611         return pos;
3612 }
3613
3614 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3615         struct task_struct *task, int tid)
3616 {
3617         char name[PROC_NUMBUF];
3618         int len = snprintf(name, sizeof(name), "%d", tid);
3619         return proc_fill_cache(filp, dirent, filldir, name, len,
3620                                 proc_task_instantiate, task, NULL);
3621 }
3622
3623 /* for the /proc/TGID/task/ directories */
3624 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3625 {
3626         struct dentry *dentry = filp->f_path.dentry;
3627         struct inode *inode = dentry->d_inode;
3628         struct task_struct *leader = NULL;
3629         struct task_struct *task;
3630         int retval = -ENOENT;
3631         ino_t ino;
3632         int tid;
3633         struct pid_namespace *ns;
3634
3635         task = get_proc_task(inode);
3636         if (!task)
3637                 goto out_no_task;
3638         rcu_read_lock();
3639         if (pid_alive(task)) {
3640                 leader = task->group_leader;
3641                 get_task_struct(leader);
3642         }
3643         rcu_read_unlock();
3644         put_task_struct(task);
3645         if (!leader)
3646                 goto out_no_task;
3647         retval = 0;
3648
3649         switch ((unsigned long)filp->f_pos) {
3650         case 0:
3651                 ino = inode->i_ino;
3652                 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) < 0)
3653                         goto out;
3654                 filp->f_pos++;
3655                 /* fall through */
3656         case 1:
3657                 ino = parent_ino(dentry);
3658                 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) < 0)
3659                         goto out;
3660                 filp->f_pos++;
3661                 /* fall through */
3662         }
3663
3664         /* f_version caches the tgid value that the last readdir call couldn't
3665          * return. lseek aka telldir automagically resets f_version to 0.
3666          */
3667         ns = filp->f_dentry->d_sb->s_fs_info;
3668         tid = (int)filp->f_version;
3669         filp->f_version = 0;
3670         for (task = first_tid(leader, tid, filp->f_pos - 2, ns);
3671              task;
3672              task = next_tid(task), filp->f_pos++) {
3673                 tid = task_pid_nr_ns(task, ns);
3674                 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3675                         /* returning this tgid failed, save it as the first
3676                          * pid for the next readir call */
3677                         filp->f_version = (u64)tid;
3678                         put_task_struct(task);
3679                         break;
3680                 }
3681         }
3682 out:
3683         put_task_struct(leader);
3684 out_no_task:
3685         return retval;
3686 }
3687
3688 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3689 {
3690         struct inode *inode = dentry->d_inode;
3691         struct task_struct *p = get_proc_task(inode);
3692         generic_fillattr(inode, stat);
3693
3694         if (p) {
3695                 stat->nlink += get_nr_threads(p);
3696                 put_task_struct(p);
3697         }
3698
3699         return 0;
3700 }
3701
3702 static const struct inode_operations proc_task_inode_operations = {
3703         .lookup         = proc_task_lookup,
3704         .getattr        = proc_task_getattr,
3705         .setattr        = proc_setattr,
3706         .permission     = proc_pid_permission,
3707 };
3708
3709 static const struct file_operations proc_task_operations = {
3710         .read           = generic_read_dir,
3711         .readdir        = proc_task_readdir,
3712         .llseek         = default_llseek,
3713 };