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 <linux/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/printk.h>
  77 #include <linux/cgroup.h>
  78 #include <linux/cpuset.h>
  79 #include <linux/audit.h>
  80 #include <linux/poll.h>
  81 #include <linux/nsproxy.h>
  82 #include <linux/oom.h>
  83 #include <linux/elf.h>
  84 #include <linux/pid_namespace.h>
  85 #include <linux/user_namespace.h>
  86 #include <linux/fs_struct.h>
  87 #include <linux/slab.h>
  88 #include <linux/flex_array.h>
  89 #include <linux/posix-timers.h>
  90 #ifdef CONFIG_HARDWALL
  91 #include <asm/hardwall.h>
  92 #endif
  93 #include <trace/events/oom.h>
  94 #include "internal.h"
  95 #include "fd.h"
  96
  97 /* NOTE:
  98  *      Implementing inode permission operations in /proc is almost
  99  *      certainly an error.  Permission checks need to happen during
 100  *      each system call not at open time.  The reason is that most of
 101  *      what we wish to check for permissions in /proc varies at runtime.
 102  *
 103  *      The classic example of a problem is opening file descriptors
 104  *      in /proc for a task before it execs a suid executable.
 105  */
 106
 107 static u8 nlink_tid;
 108 static u8 nlink_tgid;
 109
 110 struct pid_entry {
 111         const char *name;
 112         unsigned int len;
 113         umode_t mode;
 114         const struct inode_operations *iop;
 115         const struct file_operations *fop;
 116         union proc_op op;
 117 };
 118
 119 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 120         .name = (NAME),                                 \
 121         .len  = sizeof(NAME) - 1,                       \
 122         .mode = MODE,                                   \
 123         .iop  = IOP,                                    \
 124         .fop  = FOP,                                    \
 125         .op   = OP,                                     \
 126 }
 127
 128 #define DIR(NAME, MODE, iops, fops)     \
 129         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 130 #define LNK(NAME, get_link)                                     \
 131         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 132                 &proc_pid_link_inode_operations, NULL,          \
 133                 { .proc_get_link = get_link } )
 134 #define REG(NAME, MODE, fops)                           \
 135         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 136 #define ONE(NAME, MODE, show)                           \
 137         NOD(NAME, (S_IFREG|(MODE)),                     \
 138                 NULL, &proc_single_file_operations,     \
 139                 { .proc_show = show } )
 140
 141 /*
 142  * Count the number of hardlinks for the pid_entry table, excluding the .
 143  * and .. links.
 144  */
 145 static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
 146         unsigned int n)
 147 {
 148         unsigned int i;
 149         unsigned int count;
 150
 151         count = 2;
 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(d_inode(dentry));
 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(d_inode(dentry));
 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 ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 203                                      size_t _count, loff_t *pos)
 204 {
 205         struct task_struct *tsk;
 206         struct mm_struct *mm;
 207         char *page;
 208         unsigned long count = _count;
 209         unsigned long arg_start, arg_end, env_start, env_end;
 210         unsigned long len1, len2, len;
 211         unsigned long p;
 212         char c;
 213         ssize_t rv;
 214
 215         BUG_ON(*pos < 0);
 216
 217         tsk = get_proc_task(file_inode(file));
 218         if (!tsk)
 219                 return -ESRCH;
 220         mm = get_task_mm(tsk);
 221         put_task_struct(tsk);
 222         if (!mm)
 223                 return 0;
 224         /* Check if process spawned far enough to have cmdline. */
 225         if (!mm->env_end) {
 226                 rv = 0;
 227                 goto out_mmput;
 228         }
 229
 230         page = (char *)__get_free_page(GFP_TEMPORARY);
 231         if (!page) {
 232                 rv = -ENOMEM;
 233                 goto out_mmput;
 234         }
 235
 236         down_read(&mm->mmap_sem);
 237         arg_start = mm->arg_start;
 238         arg_end = mm->arg_end;
 239         env_start = mm->env_start;
 240         env_end = mm->env_end;
 241         up_read(&mm->mmap_sem);
 242
 243         BUG_ON(arg_start > arg_end);
 244         BUG_ON(env_start > env_end);
 245
 246         len1 = arg_end - arg_start;
 247         len2 = env_end - env_start;
 248
 249         /* Empty ARGV. */
 250         if (len1 == 0) {
 251                 rv = 0;
 252                 goto out_free_page;
 253         }
 254         /*
 255          * Inherently racy -- command line shares address space
 256          * with code and data.
 257          */
 258         rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0);
 259         if (rv <= 0)
 260                 goto out_free_page;
 261
 262         rv = 0;
 263
 264         if (c == '\0') {
 265                 /* Command line (set of strings) occupies whole ARGV. */
 266                 if (len1 <= *pos)
 267                         goto out_free_page;
 268
 269                 p = arg_start + *pos;
 270                 len = len1 - *pos;
 271                 while (count > 0 && len > 0) {
 272                         unsigned int _count;
 273                         int nr_read;
 274
 275                         _count = min3(count, len, PAGE_SIZE);
 276                         nr_read = access_remote_vm(mm, p, page, _count, 0);
 277                         if (nr_read < 0)
 278                                 rv = nr_read;
 279                         if (nr_read <= 0)
 280                                 goto out_free_page;
 281
 282                         if (copy_to_user(buf, page, nr_read)) {
 283                                 rv = -EFAULT;
 284                                 goto out_free_page;
 285                         }
 286
 287                         p       += nr_read;
 288                         len     -= nr_read;
 289                         buf     += nr_read;
 290                         count   -= nr_read;
 291                         rv      += nr_read;
 292                 }
 293         } else {
 294                 /*
 295                  * Command line (1 string) occupies ARGV and
 296                  * extends into ENVP.
 297                  */
 298                 struct {
 299                         unsigned long p;
 300                         unsigned long len;
 301                 } cmdline[2] = {
 302                         { .p = arg_start, .len = len1 },
 303                         { .p = env_start, .len = len2 },
 304                 };
 305                 loff_t pos1 = *pos;
 306                 unsigned int i;
 307
 308                 i = 0;
 309                 while (i < 2 && pos1 >= cmdline[i].len) {
 310                         pos1 -= cmdline[i].len;
 311                         i++;
 312                 }
 313                 while (i < 2) {
 314                         p = cmdline[i].p + pos1;
 315                         len = cmdline[i].len - pos1;
 316                         while (count > 0 && len > 0) {
 317                                 unsigned int _count, l;
 318                                 int nr_read;
 319                                 bool final;
 320
 321                                 _count = min3(count, len, PAGE_SIZE);
 322                                 nr_read = access_remote_vm(mm, p, page, _count, 0);
 323                                 if (nr_read < 0)
 324                                         rv = nr_read;
 325                                 if (nr_read <= 0)
 326                                         goto out_free_page;
 327
 328                                 /*
 329                                  * Command line can be shorter than whole ARGV
 330                                  * even if last "marker" byte says it is not.
 331                                  */
 332                                 final = false;
 333                                 l = strnlen(page, nr_read);
 334                                 if (l < nr_read) {
 335                                         nr_read = l;
 336                                         final = true;
 337                                 }
 338
 339                                 if (copy_to_user(buf, page, nr_read)) {
 340                                         rv = -EFAULT;
 341                                         goto out_free_page;
 342                                 }
 343
 344                                 p       += nr_read;
 345                                 len     -= nr_read;
 346                                 buf     += nr_read;
 347                                 count   -= nr_read;
 348                                 rv      += nr_read;
 349
 350                                 if (final)
 351                                         goto out_free_page;
 352                         }
 353
 354                         /* Only first chunk can be read partially. */
 355                         pos1 = 0;
 356                         i++;
 357                 }
 358         }
 359
 360 out_free_page:
 361         free_page((unsigned long)page);
 362 out_mmput:
 363         mmput(mm);
 364         if (rv > 0)
 365                 *pos += rv;
 366         return rv;
 367 }
 368
 369 static const struct file_operations proc_pid_cmdline_ops = {
 370         .read   = proc_pid_cmdline_read,
 371         .llseek = generic_file_llseek,
 372 };
 373
 374 #ifdef CONFIG_KALLSYMS
 375 /*
 376  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 377  * Returns the resolved symbol.  If that fails, simply return the address.
 378  */
 379 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 380                           struct pid *pid, struct task_struct *task)
 381 {
 382         unsigned long wchan;
 383         char symname[KSYM_NAME_LEN];
 384
 385         wchan = get_wchan(task);
 386
 387         if (wchan && ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)
 388                         && !lookup_symbol_name(wchan, symname))
 389                 seq_printf(m, "%s", symname);
 390         else
 391                 seq_putc(m, '0');
 392
 393         return 0;
 394 }
 395 #endif /* CONFIG_KALLSYMS */
 396
 397 static int lock_trace(struct task_struct *task)
 398 {
 399         int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 400         if (err)
 401                 return err;
 402         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 403                 mutex_unlock(&task->signal->cred_guard_mutex);
 404                 return -EPERM;
 405         }
 406         return 0;
 407 }
 408
 409 static void unlock_trace(struct task_struct *task)
 410 {
 411         mutex_unlock(&task->signal->cred_guard_mutex);
 412 }
 413
 414 #ifdef CONFIG_STACKTRACE
 415
 416 #define MAX_STACK_TRACE_DEPTH   64
 417
 418 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 419                           struct pid *pid, struct task_struct *task)
 420 {
 421         struct stack_trace trace;
 422         unsigned long *entries;
 423         int err;
 424         int i;
 425
 426         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 427         if (!entries)
 428                 return -ENOMEM;
 429
 430         trace.nr_entries        = 0;
 431         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 432         trace.entries           = entries;
 433         trace.skip              = 0;
 434
 435         err = lock_trace(task);
 436         if (!err) {
 437                 save_stack_trace_tsk(task, &trace);
 438
 439                 for (i = 0; i < trace.nr_entries; i++) {
 440                         seq_printf(m, "[<%pK>] %pB\n",
 441                                    (void *)entries[i], (void *)entries[i]);
 442                 }
 443                 unlock_trace(task);
 444         }
 445         kfree(entries);
 446
 447         return err;
 448 }
 449 #endif
 450
 451 #ifdef CONFIG_SCHED_INFO
 452 /*
 453  * Provides /proc/PID/schedstat
 454  */
 455 static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 456                               struct pid *pid, struct task_struct *task)
 457 {
 458         if (unlikely(!sched_info_on()))
 459                 seq_printf(m, "0 0 0\n");
 460         else
 461                 seq_printf(m, "%llu %llu %lu\n",
 462                    (unsigned long long)task->se.sum_exec_runtime,
 463                    (unsigned long long)task->sched_info.run_delay,
 464                    task->sched_info.pcount);
 465
 466         return 0;
 467 }
 468 #endif
 469
 470 #ifdef CONFIG_LATENCYTOP
 471 static int lstats_show_proc(struct seq_file *m, void *v)
 472 {
 473         int i;
 474         struct inode *inode = m->private;
 475         struct task_struct *task = get_proc_task(inode);
 476
 477         if (!task)
 478                 return -ESRCH;
 479         seq_puts(m, "Latency Top version : v0.1\n");
 480         for (i = 0; i < 32; i++) {
 481                 struct latency_record *lr = &task->latency_record[i];
 482                 if (lr->backtrace[0]) {
 483                         int q;
 484                         seq_printf(m, "%i %li %li",
 485                                    lr->count, lr->time, lr->max);
 486                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 487                                 unsigned long bt = lr->backtrace[q];
 488                                 if (!bt)
 489                                         break;
 490                                 if (bt == ULONG_MAX)
 491                                         break;
 492                                 seq_printf(m, " %ps", (void *)bt);
 493                         }
 494                         seq_putc(m, '\n');
 495                 }
 496
 497         }
 498         put_task_struct(task);
 499         return 0;
 500 }
 501
 502 static int lstats_open(struct inode *inode, struct file *file)
 503 {
 504         return single_open(file, lstats_show_proc, inode);
 505 }
 506
 507 static ssize_t lstats_write(struct file *file, const char __user *buf,
 508                             size_t count, loff_t *offs)
 509 {
 510         struct task_struct *task = get_proc_task(file_inode(file));
 511
 512         if (!task)
 513                 return -ESRCH;
 514         clear_all_latency_tracing(task);
 515         put_task_struct(task);
 516
 517         return count;
 518 }
 519
 520 static const struct file_operations proc_lstats_operations = {
 521         .open           = lstats_open,
 522         .read           = seq_read,
 523         .write          = lstats_write,
 524         .llseek         = seq_lseek,
 525         .release        = single_release,
 526 };
 527
 528 #endif
 529
 530 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 531                           struct pid *pid, struct task_struct *task)
 532 {
 533         unsigned long totalpages = totalram_pages + total_swap_pages;
 534         unsigned long points = 0;
 535
 536         points = oom_badness(task, NULL, NULL, totalpages) *
 537                                         1000 / totalpages;
 538         seq_printf(m, "%lu\n", points);
 539
 540         return 0;
 541 }
 542
 543 struct limit_names {
 544         const char *name;
 545         const char *unit;
 546 };
 547
 548 static const struct limit_names lnames[RLIM_NLIMITS] = {
 549         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 550         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 551         [RLIMIT_DATA] = {"Max data size", "bytes"},
 552         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 553         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 554         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 555         [RLIMIT_NPROC] = {"Max processes", "processes"},
 556         [RLIMIT_NOFILE] = {"Max open files", "files"},
 557         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 558         [RLIMIT_AS] = {"Max address space", "bytes"},
 559         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 560         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 561         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 562         [RLIMIT_NICE] = {"Max nice priority", NULL},
 563         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 564         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 565 };
 566
 567 /* Display limits for a process */
 568 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 569                            struct pid *pid, struct task_struct *task)
 570 {
 571         unsigned int i;
 572         unsigned long flags;
 573
 574         struct rlimit rlim[RLIM_NLIMITS];
 575
 576         if (!lock_task_sighand(task, &flags))
 577                 return 0;
 578         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 579         unlock_task_sighand(task, &flags);
 580
 581         /*
 582          * print the file header
 583          */
 584        seq_printf(m, "%-25s %-20s %-20s %-10s\n",
 585                   "Limit", "Soft Limit", "Hard Limit", "Units");
 586
 587         for (i = 0; i < RLIM_NLIMITS; i++) {
 588                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 589                         seq_printf(m, "%-25s %-20s ",
 590                                    lnames[i].name, "unlimited");
 591                 else
 592                         seq_printf(m, "%-25s %-20lu ",
 593                                    lnames[i].name, rlim[i].rlim_cur);
 594
 595                 if (rlim[i].rlim_max == RLIM_INFINITY)
 596                         seq_printf(m, "%-20s ", "unlimited");
 597                 else
 598                         seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 599
 600                 if (lnames[i].unit)
 601                         seq_printf(m, "%-10s\n", lnames[i].unit);
 602                 else
 603                         seq_putc(m, '\n');
 604         }
 605
 606         return 0;
 607 }
 608
 609 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 610 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 611                             struct pid *pid, struct task_struct *task)
 612 {
 613         long nr;
 614         unsigned long args[6], sp, pc;
 615         int res;
 616
 617         res = lock_trace(task);
 618         if (res)
 619                 return res;
 620
 621         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 622                 seq_puts(m, "running\n");
 623         else if (nr < 0)
 624                 seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 625         else
 626                 seq_printf(m,
 627                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 628                        nr,
 629                        args[0], args[1], args[2], args[3], args[4], args[5],
 630                        sp, pc);
 631         unlock_trace(task);
 632
 633         return 0;
 634 }
 635 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 636
 637 /************************************************************************/
 638 /*                       Here the fs part begins                        */
 639 /************************************************************************/
 640
 641 /* permission checks */
 642 static int proc_fd_access_allowed(struct inode *inode)
 643 {
 644         struct task_struct *task;
 645         int allowed = 0;
 646         /* Allow access to a task's file descriptors if it is us or we
 647          * may use ptrace attach to the process and find out that
 648          * information.
 649          */
 650         task = get_proc_task(inode);
 651         if (task) {
 652                 allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 653                 put_task_struct(task);
 654         }
 655         return allowed;
 656 }
 657
 658 int proc_setattr(struct dentry *dentry, struct iattr *attr)
 659 {
 660         int error;
 661         struct inode *inode = d_inode(dentry);
 662
 663         if (attr->ia_valid & ATTR_MODE)
 664                 return -EPERM;
 665
 666         error = setattr_prepare(dentry, attr);
 667         if (error)
 668                 return error;
 669
 670         setattr_copy(inode, attr);
 671         mark_inode_dirty(inode);
 672         return 0;
 673 }
 674
 675 /*
 676  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 677  * or euid/egid (for hide_pid_min=2)?
 678  */
 679 static bool has_pid_permissions(struct pid_namespace *pid,
 680                                  struct task_struct *task,
 681                                  int hide_pid_min)
 682 {
 683         if (pid->hide_pid < hide_pid_min)
 684                 return true;
 685         if (in_group_p(pid->pid_gid))
 686                 return true;
 687         return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 688 }
 689
 690
 691 static int proc_pid_permission(struct inode *inode, int mask)
 692 {
 693         struct pid_namespace *pid = inode->i_sb->s_fs_info;
 694         struct task_struct *task;
 695         bool has_perms;
 696
 697         task = get_proc_task(inode);
 698         if (!task)
 699                 return -ESRCH;
 700         has_perms = has_pid_permissions(pid, task, HIDEPID_NO_ACCESS);
 701         put_task_struct(task);
 702
 703         if (!has_perms) {
 704                 if (pid->hide_pid == HIDEPID_INVISIBLE) {
 705                         /*
 706                          * Let's make getdents(), stat(), and open()
 707                          * consistent with each other.  If a process
 708                          * may not stat() a file, it shouldn't be seen
 709                          * in procfs at all.
 710                          */
 711                         return -ENOENT;
 712                 }
 713
 714                 return -EPERM;
 715         }
 716         return generic_permission(inode, mask);
 717 }
 718
 719
 720
 721 static const struct inode_operations proc_def_inode_operations = {
 722         .setattr        = proc_setattr,
 723 };
 724
 725 static int proc_single_show(struct seq_file *m, void *v)
 726 {
 727         struct inode *inode = m->private;
 728         struct pid_namespace *ns;
 729         struct pid *pid;
 730         struct task_struct *task;
 731         int ret;
 732
 733         ns = inode->i_sb->s_fs_info;
 734         pid = proc_pid(inode);
 735         task = get_pid_task(pid, PIDTYPE_PID);
 736         if (!task)
 737                 return -ESRCH;
 738
 739         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 740
 741         put_task_struct(task);
 742         return ret;
 743 }
 744
 745 static int proc_single_open(struct inode *inode, struct file *filp)
 746 {
 747         return single_open(filp, proc_single_show, inode);
 748 }
 749
 750 static const struct file_operations proc_single_file_operations = {
 751         .open           = proc_single_open,
 752         .read           = seq_read,
 753         .llseek         = seq_lseek,
 754         .release        = single_release,
 755 };
 756
 757
 758 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 759 {
 760         struct task_struct *task = get_proc_task(inode);
 761         struct mm_struct *mm = ERR_PTR(-ESRCH);
 762
 763         if (task) {
 764                 mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 765                 put_task_struct(task);
 766
 767                 if (!IS_ERR_OR_NULL(mm)) {
 768                         /* ensure this mm_struct can't be freed */
 769                         mmgrab(mm);
 770                         /* but do not pin its memory */
 771                         mmput(mm);
 772                 }
 773         }
 774
 775         return mm;
 776 }
 777
 778 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 779 {
 780         struct mm_struct *mm = proc_mem_open(inode, mode);
 781
 782         if (IS_ERR(mm))
 783                 return PTR_ERR(mm);
 784
 785         file->private_data = mm;
 786         return 0;
 787 }
 788
 789 static int mem_open(struct inode *inode, struct file *file)
 790 {
 791         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 792
 793         /* OK to pass negative loff_t, we can catch out-of-range */
 794         file->f_mode |= FMODE_UNSIGNED_OFFSET;
 795
 796         return ret;
 797 }
 798
 799 static ssize_t mem_rw(struct file *file, char __user *buf,
 800                         size_t count, loff_t *ppos, int write)
 801 {
 802         struct mm_struct *mm = file->private_data;
 803         unsigned long addr = *ppos;
 804         ssize_t copied;
 805         char *page;
 806         unsigned int flags;
 807
 808         if (!mm)
 809                 return 0;
 810
 811         page = (char *)__get_free_page(GFP_TEMPORARY);
 812         if (!page)
 813                 return -ENOMEM;
 814
 815         copied = 0;
 816         if (!mmget_not_zero(mm))
 817                 goto free;
 818
 819         /* Maybe we should limit FOLL_FORCE to actual ptrace users? */
 820         flags = FOLL_FORCE;
 821         if (write)
 822                 flags |= FOLL_WRITE;
 823
 824         while (count > 0) {
 825                 int this_len = min_t(int, count, PAGE_SIZE);
 826
 827                 if (write && copy_from_user(page, buf, this_len)) {
 828                         copied = -EFAULT;
 829                         break;
 830                 }
 831
 832                 this_len = access_remote_vm(mm, addr, page, this_len, flags);
 833                 if (!this_len) {
 834                         if (!copied)
 835                                 copied = -EIO;
 836                         break;
 837                 }
 838
 839                 if (!write && copy_to_user(buf, page, this_len)) {
 840                         copied = -EFAULT;
 841                         break;
 842                 }
 843
 844                 buf += this_len;
 845                 addr += this_len;
 846                 copied += this_len;
 847                 count -= this_len;
 848         }
 849         *ppos = addr;
 850
 851         mmput(mm);
 852 free:
 853         free_page((unsigned long) page);
 854         return copied;
 855 }
 856
 857 static ssize_t mem_read(struct file *file, char __user *buf,
 858                         size_t count, loff_t *ppos)
 859 {
 860         return mem_rw(file, buf, count, ppos, 0);
 861 }
 862
 863 static ssize_t mem_write(struct file *file, const char __user *buf,
 864                          size_t count, loff_t *ppos)
 865 {
 866         return mem_rw(file, (char __user*)buf, count, ppos, 1);
 867 }
 868
 869 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 870 {
 871         switch (orig) {
 872         case 0:
 873                 file->f_pos = offset;
 874                 break;
 875         case 1:
 876                 file->f_pos += offset;
 877                 break;
 878         default:
 879                 return -EINVAL;
 880         }
 881         force_successful_syscall_return();
 882         return file->f_pos;
 883 }
 884
 885 static int mem_release(struct inode *inode, struct file *file)
 886 {
 887         struct mm_struct *mm = file->private_data;
 888         if (mm)
 889                 mmdrop(mm);
 890         return 0;
 891 }
 892
 893 static const struct file_operations proc_mem_operations = {
 894         .llseek         = mem_lseek,
 895         .read           = mem_read,
 896         .write          = mem_write,
 897         .open           = mem_open,
 898         .release        = mem_release,
 899 };
 900
 901 static int environ_open(struct inode *inode, struct file *file)
 902 {
 903         return __mem_open(inode, file, PTRACE_MODE_READ);
 904 }
 905
 906 static ssize_t environ_read(struct file *file, char __user *buf,
 907                         size_t count, loff_t *ppos)
 908 {
 909         char *page;
 910         unsigned long src = *ppos;
 911         int ret = 0;
 912         struct mm_struct *mm = file->private_data;
 913         unsigned long env_start, env_end;
 914
 915         /* Ensure the process spawned far enough to have an environment. */
 916         if (!mm || !mm->env_end)
 917                 return 0;
 918
 919         page = (char *)__get_free_page(GFP_TEMPORARY);
 920         if (!page)
 921                 return -ENOMEM;
 922
 923         ret = 0;
 924         if (!mmget_not_zero(mm))
 925                 goto free;
 926
 927         down_read(&mm->mmap_sem);
 928         env_start = mm->env_start;
 929         env_end = mm->env_end;
 930         up_read(&mm->mmap_sem);
 931
 932         while (count > 0) {
 933                 size_t this_len, max_len;
 934                 int retval;
 935
 936                 if (src >= (env_end - env_start))
 937                         break;
 938
 939                 this_len = env_end - (env_start + src);
 940
 941                 max_len = min_t(size_t, PAGE_SIZE, count);
 942                 this_len = min(max_len, this_len);
 943
 944                 retval = access_remote_vm(mm, (env_start + src), page, this_len, 0);
 945
 946                 if (retval <= 0) {
 947                         ret = retval;
 948                         break;
 949                 }
 950
 951                 if (copy_to_user(buf, page, retval)) {
 952                         ret = -EFAULT;
 953                         break;
 954                 }
 955
 956                 ret += retval;
 957                 src += retval;
 958                 buf += retval;
 959                 count -= retval;
 960         }
 961         *ppos = src;
 962         mmput(mm);
 963
 964 free:
 965         free_page((unsigned long) page);
 966         return ret;
 967 }
 968
 969 static const struct file_operations proc_environ_operations = {
 970         .open           = environ_open,
 971         .read           = environ_read,
 972         .llseek         = generic_file_llseek,
 973         .release        = mem_release,
 974 };
 975
 976 static int auxv_open(struct inode *inode, struct file *file)
 977 {
 978         return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
 979 }
 980
 981 static ssize_t auxv_read(struct file *file, char __user *buf,
 982                         size_t count, loff_t *ppos)
 983 {
 984         struct mm_struct *mm = file->private_data;
 985         unsigned int nwords = 0;
 986
 987         if (!mm)
 988                 return 0;
 989         do {
 990                 nwords += 2;
 991         } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 992         return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
 993                                        nwords * sizeof(mm->saved_auxv[0]));
 994 }
 995
 996 static const struct file_operations proc_auxv_operations = {
 997         .open           = auxv_open,
 998         .read           = auxv_read,
 999         .llseek         = generic_file_llseek,
1000         .release        = mem_release,
1001 };
1002
1003 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1004                             loff_t *ppos)
1005 {
1006         struct task_struct *task = get_proc_task(file_inode(file));
1007         char buffer[PROC_NUMBUF];
1008         int oom_adj = OOM_ADJUST_MIN;
1009         size_t len;
1010
1011         if (!task)
1012                 return -ESRCH;
1013         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1014                 oom_adj = OOM_ADJUST_MAX;
1015         else
1016                 oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1017                           OOM_SCORE_ADJ_MAX;
1018         put_task_struct(task);
1019         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1020         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1021 }
1022
1023 static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1024 {
1025         static DEFINE_MUTEX(oom_adj_mutex);
1026         struct mm_struct *mm = NULL;
1027         struct task_struct *task;
1028         int err = 0;
1029
1030         task = get_proc_task(file_inode(file));
1031         if (!task)
1032                 return -ESRCH;
1033
1034         mutex_lock(&oom_adj_mutex);
1035         if (legacy) {
1036                 if (oom_adj < task->signal->oom_score_adj &&
1037                                 !capable(CAP_SYS_RESOURCE)) {
1038                         err = -EACCES;
1039                         goto err_unlock;
1040                 }
1041                 /*
1042                  * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1043                  * /proc/pid/oom_score_adj instead.
1044                  */
1045                 pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1046                           current->comm, task_pid_nr(current), task_pid_nr(task),
1047                           task_pid_nr(task));
1048         } else {
1049                 if ((short)oom_adj < task->signal->oom_score_adj_min &&
1050                                 !capable(CAP_SYS_RESOURCE)) {
1051                         err = -EACCES;
1052                         goto err_unlock;
1053                 }
1054         }
1055
1056         /*
1057          * Make sure we will check other processes sharing the mm if this is
1058          * not vfrok which wants its own oom_score_adj.
1059          * pin the mm so it doesn't go away and get reused after task_unlock
1060          */
1061         if (!task->vfork_done) {
1062                 struct task_struct *p = find_lock_task_mm(task);
1063
1064                 if (p) {
1065                         if (atomic_read(&p->mm->mm_users) > 1) {
1066                                 mm = p->mm;
1067                                 mmgrab(mm);
1068                         }
1069                         task_unlock(p);
1070                 }
1071         }
1072
1073         task->signal->oom_score_adj = oom_adj;
1074         if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1075                 task->signal->oom_score_adj_min = (short)oom_adj;
1076         trace_oom_score_adj_update(task);
1077
1078         if (mm) {
1079                 struct task_struct *p;
1080
1081                 rcu_read_lock();
1082                 for_each_process(p) {
1083                         if (same_thread_group(task, p))
1084                                 continue;
1085
1086                         /* do not touch kernel threads or the global init */
1087                         if (p->flags & PF_KTHREAD || is_global_init(p))
1088                                 continue;
1089
1090                         task_lock(p);
1091                         if (!p->vfork_done && process_shares_mm(p, mm)) {
1092                                 pr_info("updating oom_score_adj for %d (%s) from %d to %d because it shares mm with %d (%s). Report if this is unexpected.\n",
1093                                                 task_pid_nr(p), p->comm,
1094                                                 p->signal->oom_score_adj, oom_adj,
1095                                                 task_pid_nr(task), task->comm);
1096                                 p->signal->oom_score_adj = oom_adj;
1097                                 if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1098                                         p->signal->oom_score_adj_min = (short)oom_adj;
1099                         }
1100                         task_unlock(p);
1101                 }
1102                 rcu_read_unlock();
1103                 mmdrop(mm);
1104         }
1105 err_unlock:
1106         mutex_unlock(&oom_adj_mutex);
1107         put_task_struct(task);
1108         return err;
1109 }
1110
1111 /*
1112  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1113  * kernels.  The effective policy is defined by oom_score_adj, which has a
1114  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1115  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1116  * Processes that become oom disabled via oom_adj will still be oom disabled
1117  * with this implementation.
1118  *
1119  * oom_adj cannot be removed since existing userspace binaries use it.
1120  */
1121 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1122                              size_t count, loff_t *ppos)
1123 {
1124         char buffer[PROC_NUMBUF];
1125         int oom_adj;
1126         int err;
1127
1128         memset(buffer, 0, sizeof(buffer));
1129         if (count > sizeof(buffer) - 1)
1130                 count = sizeof(buffer) - 1;
1131         if (copy_from_user(buffer, buf, count)) {
1132                 err = -EFAULT;
1133                 goto out;
1134         }
1135
1136         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1137         if (err)
1138                 goto out;
1139         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1140              oom_adj != OOM_DISABLE) {
1141                 err = -EINVAL;
1142                 goto out;
1143         }
1144
1145         /*
1146          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1147          * value is always attainable.
1148          */
1149         if (oom_adj == OOM_ADJUST_MAX)
1150                 oom_adj = OOM_SCORE_ADJ_MAX;
1151         else
1152                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1153
1154         err = __set_oom_adj(file, oom_adj, true);
1155 out:
1156         return err < 0 ? err : count;
1157 }
1158
1159 static const struct file_operations proc_oom_adj_operations = {
1160         .read           = oom_adj_read,
1161         .write          = oom_adj_write,
1162         .llseek         = generic_file_llseek,
1163 };
1164
1165 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1166                                         size_t count, loff_t *ppos)
1167 {
1168         struct task_struct *task = get_proc_task(file_inode(file));
1169         char buffer[PROC_NUMBUF];
1170         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1171         size_t len;
1172
1173         if (!task)
1174                 return -ESRCH;
1175         oom_score_adj = task->signal->oom_score_adj;
1176         put_task_struct(task);
1177         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1178         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1179 }
1180
1181 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1182                                         size_t count, loff_t *ppos)
1183 {
1184         char buffer[PROC_NUMBUF];
1185         int oom_score_adj;
1186         int err;
1187
1188         memset(buffer, 0, sizeof(buffer));
1189         if (count > sizeof(buffer) - 1)
1190                 count = sizeof(buffer) - 1;
1191         if (copy_from_user(buffer, buf, count)) {
1192                 err = -EFAULT;
1193                 goto out;
1194         }
1195
1196         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1197         if (err)
1198                 goto out;
1199         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1200                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1201                 err = -EINVAL;
1202                 goto out;
1203         }
1204
1205         err = __set_oom_adj(file, oom_score_adj, false);
1206 out:
1207         return err < 0 ? err : count;
1208 }
1209
1210 static const struct file_operations proc_oom_score_adj_operations = {
1211         .read           = oom_score_adj_read,
1212         .write          = oom_score_adj_write,
1213         .llseek         = default_llseek,
1214 };
1215
1216 #ifdef CONFIG_AUDITSYSCALL
1217 #define TMPBUFLEN 11
1218 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1219                                   size_t count, loff_t *ppos)
1220 {
1221         struct inode * inode = file_inode(file);
1222         struct task_struct *task = get_proc_task(inode);
1223         ssize_t length;
1224         char tmpbuf[TMPBUFLEN];
1225
1226         if (!task)
1227                 return -ESRCH;
1228         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1229                            from_kuid(file->f_cred->user_ns,
1230                                      audit_get_loginuid(task)));
1231         put_task_struct(task);
1232         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1233 }
1234
1235 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1236                                    size_t count, loff_t *ppos)
1237 {
1238         struct inode * inode = file_inode(file);
1239         uid_t loginuid;
1240         kuid_t kloginuid;
1241         int rv;
1242
1243         rcu_read_lock();
1244         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1245                 rcu_read_unlock();
1246                 return -EPERM;
1247         }
1248         rcu_read_unlock();
1249
1250         if (*ppos != 0) {
1251                 /* No partial writes. */
1252                 return -EINVAL;
1253         }
1254
1255         rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1256         if (rv < 0)
1257                 return rv;
1258
1259         /* is userspace tring to explicitly UNSET the loginuid? */
1260         if (loginuid == AUDIT_UID_UNSET) {
1261                 kloginuid = INVALID_UID;
1262         } else {
1263                 kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1264                 if (!uid_valid(kloginuid))
1265                         return -EINVAL;
1266         }
1267
1268         rv = audit_set_loginuid(kloginuid);
1269         if (rv < 0)
1270                 return rv;
1271         return count;
1272 }
1273
1274 static const struct file_operations proc_loginuid_operations = {
1275         .read           = proc_loginuid_read,
1276         .write          = proc_loginuid_write,
1277         .llseek         = generic_file_llseek,
1278 };
1279
1280 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1281                                   size_t count, loff_t *ppos)
1282 {
1283         struct inode * inode = file_inode(file);
1284         struct task_struct *task = get_proc_task(inode);
1285         ssize_t length;
1286         char tmpbuf[TMPBUFLEN];
1287
1288         if (!task)
1289                 return -ESRCH;
1290         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1291                                 audit_get_sessionid(task));
1292         put_task_struct(task);
1293         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1294 }
1295
1296 static const struct file_operations proc_sessionid_operations = {
1297         .read           = proc_sessionid_read,
1298         .llseek         = generic_file_llseek,
1299 };
1300 #endif
1301
1302 #ifdef CONFIG_FAULT_INJECTION
1303 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1304                                       size_t count, loff_t *ppos)
1305 {
1306         struct task_struct *task = get_proc_task(file_inode(file));
1307         char buffer[PROC_NUMBUF];
1308         size_t len;
1309         int make_it_fail;
1310
1311         if (!task)
1312                 return -ESRCH;
1313         make_it_fail = task->make_it_fail;
1314         put_task_struct(task);
1315
1316         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1317
1318         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1319 }
1320
1321 static ssize_t proc_fault_inject_write(struct file * file,
1322                         const char __user * buf, size_t count, loff_t *ppos)
1323 {
1324         struct task_struct *task;
1325         char buffer[PROC_NUMBUF];
1326         int make_it_fail;
1327         int rv;
1328
1329         if (!capable(CAP_SYS_RESOURCE))
1330                 return -EPERM;
1331         memset(buffer, 0, sizeof(buffer));
1332         if (count > sizeof(buffer) - 1)
1333                 count = sizeof(buffer) - 1;
1334         if (copy_from_user(buffer, buf, count))
1335                 return -EFAULT;
1336         rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1337         if (rv < 0)
1338                 return rv;
1339         if (make_it_fail < 0 || make_it_fail > 1)
1340                 return -EINVAL;
1341
1342         task = get_proc_task(file_inode(file));
1343         if (!task)
1344                 return -ESRCH;
1345         task->make_it_fail = make_it_fail;
1346         put_task_struct(task);
1347
1348         return count;
1349 }
1350
1351 static const struct file_operations proc_fault_inject_operations = {
1352         .read           = proc_fault_inject_read,
1353         .write          = proc_fault_inject_write,
1354         .llseek         = generic_file_llseek,
1355 };
1356 #endif
1357
1358
1359 #ifdef CONFIG_SCHED_DEBUG
1360 /*
1361  * Print out various scheduling related per-task fields:
1362  */
1363 static int sched_show(struct seq_file *m, void *v)
1364 {
1365         struct inode *inode = m->private;
1366         struct task_struct *p;
1367
1368         p = get_proc_task(inode);
1369         if (!p)
1370                 return -ESRCH;
1371         proc_sched_show_task(p, m);
1372
1373         put_task_struct(p);
1374
1375         return 0;
1376 }
1377
1378 static ssize_t
1379 sched_write(struct file *file, const char __user *buf,
1380             size_t count, loff_t *offset)
1381 {
1382         struct inode *inode = file_inode(file);
1383         struct task_struct *p;
1384
1385         p = get_proc_task(inode);
1386         if (!p)
1387                 return -ESRCH;
1388         proc_sched_set_task(p);
1389
1390         put_task_struct(p);
1391
1392         return count;
1393 }
1394
1395 static int sched_open(struct inode *inode, struct file *filp)
1396 {
1397         return single_open(filp, sched_show, inode);
1398 }
1399
1400 static const struct file_operations proc_pid_sched_operations = {
1401         .open           = sched_open,
1402         .read           = seq_read,
1403         .write          = sched_write,
1404         .llseek         = seq_lseek,
1405         .release        = single_release,
1406 };
1407
1408 #endif
1409
1410 #ifdef CONFIG_SCHED_AUTOGROUP
1411 /*
1412  * Print out autogroup related information:
1413  */
1414 static int sched_autogroup_show(struct seq_file *m, void *v)
1415 {
1416         struct inode *inode = m->private;
1417         struct task_struct *p;
1418
1419         p = get_proc_task(inode);
1420         if (!p)
1421                 return -ESRCH;
1422         proc_sched_autogroup_show_task(p, m);
1423
1424         put_task_struct(p);
1425
1426         return 0;
1427 }
1428
1429 static ssize_t
1430 sched_autogroup_write(struct file *file, const char __user *buf,
1431             size_t count, loff_t *offset)
1432 {
1433         struct inode *inode = file_inode(file);
1434         struct task_struct *p;
1435         char buffer[PROC_NUMBUF];
1436         int nice;
1437         int err;
1438
1439         memset(buffer, 0, sizeof(buffer));
1440         if (count > sizeof(buffer) - 1)
1441                 count = sizeof(buffer) - 1;
1442         if (copy_from_user(buffer, buf, count))
1443                 return -EFAULT;
1444
1445         err = kstrtoint(strstrip(buffer), 0, &nice);
1446         if (err < 0)
1447                 return err;
1448
1449         p = get_proc_task(inode);
1450         if (!p)
1451                 return -ESRCH;
1452
1453         err = proc_sched_autogroup_set_nice(p, nice);
1454         if (err)
1455                 count = err;
1456
1457         put_task_struct(p);
1458
1459         return count;
1460 }
1461
1462 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1463 {
1464         int ret;
1465
1466         ret = single_open(filp, sched_autogroup_show, NULL);
1467         if (!ret) {
1468                 struct seq_file *m = filp->private_data;
1469
1470                 m->private = inode;
1471         }
1472         return ret;
1473 }
1474
1475 static const struct file_operations proc_pid_sched_autogroup_operations = {
1476         .open           = sched_autogroup_open,
1477         .read           = seq_read,
1478         .write          = sched_autogroup_write,
1479         .llseek         = seq_lseek,
1480         .release        = single_release,
1481 };
1482
1483 #endif /* CONFIG_SCHED_AUTOGROUP */
1484
1485 static ssize_t comm_write(struct file *file, const char __user *buf,
1486                                 size_t count, loff_t *offset)
1487 {
1488         struct inode *inode = file_inode(file);
1489         struct task_struct *p;
1490         char buffer[TASK_COMM_LEN];
1491         const size_t maxlen = sizeof(buffer) - 1;
1492
1493         memset(buffer, 0, sizeof(buffer));
1494         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1495                 return -EFAULT;
1496
1497         p = get_proc_task(inode);
1498         if (!p)
1499                 return -ESRCH;
1500
1501         if (same_thread_group(current, p))
1502                 set_task_comm(p, buffer);
1503         else
1504                 count = -EINVAL;
1505
1506         put_task_struct(p);
1507
1508         return count;
1509 }
1510
1511 static int comm_show(struct seq_file *m, void *v)
1512 {
1513         struct inode *inode = m->private;
1514         struct task_struct *p;
1515
1516         p = get_proc_task(inode);
1517         if (!p)
1518                 return -ESRCH;
1519
1520         task_lock(p);
1521         seq_printf(m, "%s\n", p->comm);
1522         task_unlock(p);
1523
1524         put_task_struct(p);
1525
1526         return 0;
1527 }
1528
1529 static int comm_open(struct inode *inode, struct file *filp)
1530 {
1531         return single_open(filp, comm_show, inode);
1532 }
1533
1534 static const struct file_operations proc_pid_set_comm_operations = {
1535         .open           = comm_open,
1536         .read           = seq_read,
1537         .write          = comm_write,
1538         .llseek         = seq_lseek,
1539         .release        = single_release,
1540 };
1541
1542 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1543 {
1544         struct task_struct *task;
1545         struct file *exe_file;
1546
1547         task = get_proc_task(d_inode(dentry));
1548         if (!task)
1549                 return -ENOENT;
1550         exe_file = get_task_exe_file(task);
1551         put_task_struct(task);
1552         if (exe_file) {
1553                 *exe_path = exe_file->f_path;
1554                 path_get(&exe_file->f_path);
1555                 fput(exe_file);
1556                 return 0;
1557         } else
1558                 return -ENOENT;
1559 }
1560
1561 static const char *proc_pid_get_link(struct dentry *dentry,
1562                                      struct inode *inode,
1563                                      struct delayed_call *done)
1564 {
1565         struct path path;
1566         int error = -EACCES;
1567
1568         if (!dentry)
1569                 return ERR_PTR(-ECHILD);
1570
1571         /* Are we allowed to snoop on the tasks file descriptors? */
1572         if (!proc_fd_access_allowed(inode))
1573                 goto out;
1574
1575         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1576         if (error)
1577                 goto out;
1578
1579         nd_jump_link(&path);
1580         return NULL;
1581 out:
1582         return ERR_PTR(error);
1583 }
1584
1585 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1586 {
1587         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1588         char *pathname;
1589         int len;
1590
1591         if (!tmp)
1592                 return -ENOMEM;
1593
1594         pathname = d_path(path, tmp, PAGE_SIZE);
1595         len = PTR_ERR(pathname);
1596         if (IS_ERR(pathname))
1597                 goto out;
1598         len = tmp + PAGE_SIZE - 1 - pathname;
1599
1600         if (len > buflen)
1601                 len = buflen;
1602         if (copy_to_user(buffer, pathname, len))
1603                 len = -EFAULT;
1604  out:
1605         free_page((unsigned long)tmp);
1606         return len;
1607 }
1608
1609 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1610 {
1611         int error = -EACCES;
1612         struct inode *inode = d_inode(dentry);
1613         struct path path;
1614
1615         /* Are we allowed to snoop on the tasks file descriptors? */
1616         if (!proc_fd_access_allowed(inode))
1617                 goto out;
1618
1619         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1620         if (error)
1621                 goto out;
1622
1623         error = do_proc_readlink(&path, buffer, buflen);
1624         path_put(&path);
1625 out:
1626         return error;
1627 }
1628
1629 const struct inode_operations proc_pid_link_inode_operations = {
1630         .readlink       = proc_pid_readlink,
1631         .get_link       = proc_pid_get_link,
1632         .setattr        = proc_setattr,
1633 };
1634
1635
1636 /* building an inode */
1637
1638 void task_dump_owner(struct task_struct *task, mode_t mode,
1639                      kuid_t *ruid, kgid_t *rgid)
1640 {
1641         /* Depending on the state of dumpable compute who should own a
1642          * proc file for a task.
1643          */
1644         const struct cred *cred;
1645         kuid_t uid;
1646         kgid_t gid;
1647
1648         /* Default to the tasks effective ownership */
1649         rcu_read_lock();
1650         cred = __task_cred(task);
1651         uid = cred->euid;
1652         gid = cred->egid;
1653         rcu_read_unlock();
1654
1655         /*
1656          * Before the /proc/pid/status file was created the only way to read
1657          * the effective uid of a /process was to stat /proc/pid.  Reading
1658          * /proc/pid/status is slow enough that procps and other packages
1659          * kept stating /proc/pid.  To keep the rules in /proc simple I have
1660          * made this apply to all per process world readable and executable
1661          * directories.
1662          */
1663         if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
1664                 struct mm_struct *mm;
1665                 task_lock(task);
1666                 mm = task->mm;
1667                 /* Make non-dumpable tasks owned by some root */
1668                 if (mm) {
1669                         if (get_dumpable(mm) != SUID_DUMP_USER) {
1670                                 struct user_namespace *user_ns = mm->user_ns;
1671
1672                                 uid = make_kuid(user_ns, 0);
1673                                 if (!uid_valid(uid))
1674                                         uid = GLOBAL_ROOT_UID;
1675
1676                                 gid = make_kgid(user_ns, 0);
1677                                 if (!gid_valid(gid))
1678                                         gid = GLOBAL_ROOT_GID;
1679                         }
1680                 } else {
1681                         uid = GLOBAL_ROOT_UID;
1682                         gid = GLOBAL_ROOT_GID;
1683                 }
1684                 task_unlock(task);
1685         }
1686         *ruid = uid;
1687         *rgid = gid;
1688 }
1689
1690 struct inode *proc_pid_make_inode(struct super_block * sb,
1691                                   struct task_struct *task, umode_t mode)
1692 {
1693         struct inode * inode;
1694         struct proc_inode *ei;
1695
1696         /* We need a new inode */
1697
1698         inode = new_inode(sb);
1699         if (!inode)
1700                 goto out;
1701
1702         /* Common stuff */
1703         ei = PROC_I(inode);
1704         inode->i_mode = mode;
1705         inode->i_ino = get_next_ino();
1706         inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1707         inode->i_op = &proc_def_inode_operations;
1708
1709         /*
1710          * grab the reference to task.
1711          */
1712         ei->pid = get_task_pid(task, PIDTYPE_PID);
1713         if (!ei->pid)
1714                 goto out_unlock;
1715
1716         task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1717         security_task_to_inode(task, inode);
1718
1719 out:
1720         return inode;
1721
1722 out_unlock:
1723         iput(inode);
1724         return NULL;
1725 }
1726
1727 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1728 {
1729         struct inode *inode = d_inode(dentry);
1730         struct task_struct *task;
1731         struct pid_namespace *pid = dentry->d_sb->s_fs_info;
1732
1733         generic_fillattr(inode, stat);
1734
1735         rcu_read_lock();
1736         stat->uid = GLOBAL_ROOT_UID;
1737         stat->gid = GLOBAL_ROOT_GID;
1738         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1739         if (task) {
1740                 if (!has_pid_permissions(pid, task, HIDEPID_INVISIBLE)) {
1741                         rcu_read_unlock();
1742                         /*
1743                          * This doesn't prevent learning whether PID exists,
1744                          * it only makes getattr() consistent with readdir().
1745                          */
1746                         return -ENOENT;
1747                 }
1748                 task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
1749         }
1750         rcu_read_unlock();
1751         return 0;
1752 }
1753
1754 /* dentry stuff */
1755
1756 /*
1757  *      Exceptional case: normally we are not allowed to unhash a busy
1758  * directory. In this case, however, we can do it - no aliasing problems
1759  * due to the way we treat inodes.
1760  *
1761  * Rewrite the inode's ownerships here because the owning task may have
1762  * performed a setuid(), etc.
1763  *
1764  */
1765 int pid_revalidate(struct dentry *dentry, unsigned int flags)
1766 {
1767         struct inode *inode;
1768         struct task_struct *task;
1769
1770         if (flags & LOOKUP_RCU)
1771                 return -ECHILD;
1772
1773         inode = d_inode(dentry);
1774         task = get_proc_task(inode);
1775
1776         if (task) {
1777                 task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
1778
1779                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1780                 security_task_to_inode(task, inode);
1781                 put_task_struct(task);
1782                 return 1;
1783         }
1784         return 0;
1785 }
1786
1787 static inline bool proc_inode_is_dead(struct inode *inode)
1788 {
1789         return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1790 }
1791
1792 int pid_delete_dentry(const struct dentry *dentry)
1793 {
1794         /* Is the task we represent dead?
1795          * If so, then don't put the dentry on the lru list,
1796          * kill it immediately.
1797          */
1798         return proc_inode_is_dead(d_inode(dentry));
1799 }
1800
1801 const struct dentry_operations pid_dentry_operations =
1802 {
1803         .d_revalidate   = pid_revalidate,
1804         .d_delete       = pid_delete_dentry,
1805 };
1806
1807 /* Lookups */
1808
1809 /*
1810  * Fill a directory entry.
1811  *
1812  * If possible create the dcache entry and derive our inode number and
1813  * file type from dcache entry.
1814  *
1815  * Since all of the proc inode numbers are dynamically generated, the inode
1816  * numbers do not exist until the inode is cache.  This means creating the
1817  * the dcache entry in readdir is necessary to keep the inode numbers
1818  * reported by readdir in sync with the inode numbers reported
1819  * by stat.
1820  */
1821 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1822         const char *name, int len,
1823         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1824 {
1825         struct dentry *child, *dir = file->f_path.dentry;
1826         struct qstr qname = QSTR_INIT(name, len);
1827         struct inode *inode;
1828         unsigned type;
1829         ino_t ino;
1830
1831         child = d_hash_and_lookup(dir, &qname);
1832         if (!child) {
1833                 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1834                 child = d_alloc_parallel(dir, &qname, &wq);
1835                 if (IS_ERR(child))
1836                         goto end_instantiate;
1837                 if (d_in_lookup(child)) {
1838                         int err = instantiate(d_inode(dir), child, task, ptr);
1839                         d_lookup_done(child);
1840                         if (err < 0) {
1841                                 dput(child);
1842                                 goto end_instantiate;
1843                         }
1844                 }
1845         }
1846         inode = d_inode(child);
1847         ino = inode->i_ino;
1848         type = inode->i_mode >> 12;
1849         dput(child);
1850         return dir_emit(ctx, name, len, ino, type);
1851
1852 end_instantiate:
1853         return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
1854 }
1855
1856 /*
1857  * dname_to_vma_addr - maps a dentry name into two unsigned longs
1858  * which represent vma start and end addresses.
1859  */
1860 static int dname_to_vma_addr(struct dentry *dentry,
1861                              unsigned long *start, unsigned long *end)
1862 {
1863         if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
1864                 return -EINVAL;
1865
1866         return 0;
1867 }
1868
1869 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1870 {
1871         unsigned long vm_start, vm_end;
1872         bool exact_vma_exists = false;
1873         struct mm_struct *mm = NULL;
1874         struct task_struct *task;
1875         struct inode *inode;
1876         int status = 0;
1877
1878         if (flags & LOOKUP_RCU)
1879                 return -ECHILD;
1880
1881         inode = d_inode(dentry);
1882         task = get_proc_task(inode);
1883         if (!task)
1884                 goto out_notask;
1885
1886         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1887         if (IS_ERR_OR_NULL(mm))
1888                 goto out;
1889
1890         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1891                 down_read(&mm->mmap_sem);
1892                 exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1893                 up_read(&mm->mmap_sem);
1894         }
1895
1896         mmput(mm);
1897
1898         if (exact_vma_exists) {
1899                 task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1900
1901                 security_task_to_inode(task, inode);
1902                 status = 1;
1903         }
1904
1905 out:
1906         put_task_struct(task);
1907
1908 out_notask:
1909         return status;
1910 }
1911
1912 static const struct dentry_operations tid_map_files_dentry_operations = {
1913         .d_revalidate   = map_files_d_revalidate,
1914         .d_delete       = pid_delete_dentry,
1915 };
1916
1917 static int map_files_get_link(struct dentry *dentry, struct path *path)
1918 {
1919         unsigned long vm_start, vm_end;
1920         struct vm_area_struct *vma;
1921         struct task_struct *task;
1922         struct mm_struct *mm;
1923         int rc;
1924
1925         rc = -ENOENT;
1926         task = get_proc_task(d_inode(dentry));
1927         if (!task)
1928                 goto out;
1929
1930         mm = get_task_mm(task);
1931         put_task_struct(task);
1932         if (!mm)
1933                 goto out;
1934
1935         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
1936         if (rc)
1937                 goto out_mmput;
1938
1939         rc = -ENOENT;
1940         down_read(&mm->mmap_sem);
1941         vma = find_exact_vma(mm, vm_start, vm_end);
1942         if (vma && vma->vm_file) {
1943                 *path = vma->vm_file->f_path;
1944                 path_get(path);
1945                 rc = 0;
1946         }
1947         up_read(&mm->mmap_sem);
1948
1949 out_mmput:
1950         mmput(mm);
1951 out:
1952         return rc;
1953 }
1954
1955 struct map_files_info {
1956         fmode_t         mode;
1957         unsigned int    len;
1958         unsigned char   name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
1959 };
1960
1961 /*
1962  * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
1963  * symlinks may be used to bypass permissions on ancestor directories in the
1964  * path to the file in question.
1965  */
1966 static const char *
1967 proc_map_files_get_link(struct dentry *dentry,
1968                         struct inode *inode,
1969                         struct delayed_call *done)
1970 {
1971         if (!capable(CAP_SYS_ADMIN))
1972                 return ERR_PTR(-EPERM);
1973
1974         return proc_pid_get_link(dentry, inode, done);
1975 }
1976
1977 /*
1978  * Identical to proc_pid_link_inode_operations except for get_link()
1979  */
1980 static const struct inode_operations proc_map_files_link_inode_operations = {
1981         .readlink       = proc_pid_readlink,
1982         .get_link       = proc_map_files_get_link,
1983         .setattr        = proc_setattr,
1984 };
1985
1986 static int
1987 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
1988                            struct task_struct *task, const void *ptr)
1989 {
1990         fmode_t mode = (fmode_t)(unsigned long)ptr;
1991         struct proc_inode *ei;
1992         struct inode *inode;
1993
1994         inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK |
1995                                     ((mode & FMODE_READ ) ? S_IRUSR : 0) |
1996                                     ((mode & FMODE_WRITE) ? S_IWUSR : 0));
1997         if (!inode)
1998                 return -ENOENT;
1999
2000         ei = PROC_I(inode);
2001         ei->op.proc_get_link = map_files_get_link;
2002
2003         inode->i_op = &proc_map_files_link_inode_operations;
2004         inode->i_size = 64;
2005
2006         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2007         d_add(dentry, inode);
2008
2009         return 0;
2010 }
2011
2012 static struct dentry *proc_map_files_lookup(struct inode *dir,
2013                 struct dentry *dentry, unsigned int flags)
2014 {
2015         unsigned long vm_start, vm_end;
2016         struct vm_area_struct *vma;
2017         struct task_struct *task;
2018         int result;
2019         struct mm_struct *mm;
2020
2021         result = -ENOENT;
2022         task = get_proc_task(dir);
2023         if (!task)
2024                 goto out;
2025
2026         result = -EACCES;
2027         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2028                 goto out_put_task;
2029
2030         result = -ENOENT;
2031         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2032                 goto out_put_task;
2033
2034         mm = get_task_mm(task);
2035         if (!mm)
2036                 goto out_put_task;
2037
2038         down_read(&mm->mmap_sem);
2039         vma = find_exact_vma(mm, vm_start, vm_end);
2040         if (!vma)
2041                 goto out_no_vma;
2042
2043         if (vma->vm_file)
2044                 result = proc_map_files_instantiate(dir, dentry, task,
2045                                 (void *)(unsigned long)vma->vm_file->f_mode);
2046
2047 out_no_vma:
2048         up_read(&mm->mmap_sem);
2049         mmput(mm);
2050 out_put_task:
2051         put_task_struct(task);
2052 out:
2053         return ERR_PTR(result);
2054 }
2055
2056 static const struct inode_operations proc_map_files_inode_operations = {
2057         .lookup         = proc_map_files_lookup,
2058         .permission     = proc_fd_permission,
2059         .setattr        = proc_setattr,
2060 };
2061
2062 static int
2063 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2064 {
2065         struct vm_area_struct *vma;
2066         struct task_struct *task;
2067         struct mm_struct *mm;
2068         unsigned long nr_files, pos, i;
2069         struct flex_array *fa = NULL;
2070         struct map_files_info info;
2071         struct map_files_info *p;
2072         int ret;
2073
2074         ret = -ENOENT;
2075         task = get_proc_task(file_inode(file));
2076         if (!task)
2077                 goto out;
2078
2079         ret = -EACCES;
2080         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2081                 goto out_put_task;
2082
2083         ret = 0;
2084         if (!dir_emit_dots(file, ctx))
2085                 goto out_put_task;
2086
2087         mm = get_task_mm(task);
2088         if (!mm)
2089                 goto out_put_task;
2090         down_read(&mm->mmap_sem);
2091
2092         nr_files = 0;
2093
2094         /*
2095          * We need two passes here:
2096          *
2097          *  1) Collect vmas of mapped files with mmap_sem taken
2098          *  2) Release mmap_sem and instantiate entries
2099          *
2100          * otherwise we get lockdep complained, since filldir()
2101          * routine might require mmap_sem taken in might_fault().
2102          */
2103
2104         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2105                 if (vma->vm_file && ++pos > ctx->pos)
2106                         nr_files++;
2107         }
2108
2109         if (nr_files) {
2110                 fa = flex_array_alloc(sizeof(info), nr_files,
2111                                         GFP_KERNEL);
2112                 if (!fa || flex_array_prealloc(fa, 0, nr_files,
2113                                                 GFP_KERNEL)) {
2114                         ret = -ENOMEM;
2115                         if (fa)
2116                                 flex_array_free(fa);
2117                         up_read(&mm->mmap_sem);
2118                         mmput(mm);
2119                         goto out_put_task;
2120                 }
2121                 for (i = 0, vma = mm->mmap, pos = 2; vma;
2122                                 vma = vma->vm_next) {
2123                         if (!vma->vm_file)
2124                                 continue;
2125                         if (++pos <= ctx->pos)
2126                                 continue;
2127
2128                         info.mode = vma->vm_file->f_mode;
2129                         info.len = snprintf(info.name,
2130                                         sizeof(info.name), "%lx-%lx",
2131                                         vma->vm_start, vma->vm_end);
2132                         if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2133                                 BUG();
2134                 }
2135         }
2136         up_read(&mm->mmap_sem);
2137
2138         for (i = 0; i < nr_files; i++) {
2139                 p = flex_array_get(fa, i);
2140                 if (!proc_fill_cache(file, ctx,
2141                                       p->name, p->len,
2142                                       proc_map_files_instantiate,
2143                                       task,
2144                                       (void *)(unsigned long)p->mode))
2145                         break;
2146                 ctx->pos++;
2147         }
2148         if (fa)
2149                 flex_array_free(fa);
2150         mmput(mm);
2151
2152 out_put_task:
2153         put_task_struct(task);
2154 out:
2155         return ret;
2156 }
2157
2158 static const struct file_operations proc_map_files_operations = {
2159         .read           = generic_read_dir,
2160         .iterate_shared = proc_map_files_readdir,
2161         .llseek         = generic_file_llseek,
2162 };
2163
2164 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2165 struct timers_private {
2166         struct pid *pid;
2167         struct task_struct *task;
2168         struct sighand_struct *sighand;
2169         struct pid_namespace *ns;
2170         unsigned long flags;
2171 };
2172
2173 static void *timers_start(struct seq_file *m, loff_t *pos)
2174 {
2175         struct timers_private *tp = m->private;
2176
2177         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2178         if (!tp->task)
2179                 return ERR_PTR(-ESRCH);
2180
2181         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2182         if (!tp->sighand)
2183                 return ERR_PTR(-ESRCH);
2184
2185         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2186 }
2187
2188 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2189 {
2190         struct timers_private *tp = m->private;
2191         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2192 }
2193
2194 static void timers_stop(struct seq_file *m, void *v)
2195 {
2196         struct timers_private *tp = m->private;
2197
2198         if (tp->sighand) {
2199                 unlock_task_sighand(tp->task, &tp->flags);
2200                 tp->sighand = NULL;
2201         }
2202
2203         if (tp->task) {
2204                 put_task_struct(tp->task);
2205                 tp->task = NULL;
2206         }
2207 }
2208
2209 static int show_timer(struct seq_file *m, void *v)
2210 {
2211         struct k_itimer *timer;
2212         struct timers_private *tp = m->private;
2213         int notify;
2214         static const char * const nstr[] = {
2215                 [SIGEV_SIGNAL] = "signal",
2216                 [SIGEV_NONE] = "none",
2217                 [SIGEV_THREAD] = "thread",
2218         };
2219
2220         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2221         notify = timer->it_sigev_notify;
2222
2223         seq_printf(m, "ID: %d\n", timer->it_id);
2224         seq_printf(m, "signal: %d/%p\n",
2225                    timer->sigq->info.si_signo,
2226                    timer->sigq->info.si_value.sival_ptr);
2227         seq_printf(m, "notify: %s/%s.%d\n",
2228                    nstr[notify & ~SIGEV_THREAD_ID],
2229                    (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2230                    pid_nr_ns(timer->it_pid, tp->ns));
2231         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2232
2233         return 0;
2234 }
2235
2236 static const struct seq_operations proc_timers_seq_ops = {
2237         .start  = timers_start,
2238         .next   = timers_next,
2239         .stop   = timers_stop,
2240         .show   = show_timer,
2241 };
2242
2243 static int proc_timers_open(struct inode *inode, struct file *file)
2244 {
2245         struct timers_private *tp;
2246
2247         tp = __seq_open_private(file, &proc_timers_seq_ops,
2248                         sizeof(struct timers_private));
2249         if (!tp)
2250                 return -ENOMEM;
2251
2252         tp->pid = proc_pid(inode);
2253         tp->ns = inode->i_sb->s_fs_info;
2254         return 0;
2255 }
2256
2257 static const struct file_operations proc_timers_operations = {
2258         .open           = proc_timers_open,
2259         .read           = seq_read,
2260         .llseek         = seq_lseek,
2261         .release        = seq_release_private,
2262 };
2263 #endif
2264
2265 static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2266                                         size_t count, loff_t *offset)
2267 {
2268         struct inode *inode = file_inode(file);
2269         struct task_struct *p;
2270         u64 slack_ns;
2271         int err;
2272
2273         err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2274         if (err < 0)
2275                 return err;
2276
2277         p = get_proc_task(inode);
2278         if (!p)
2279                 return -ESRCH;
2280
2281         if (p != current) {
2282                 if (!capable(CAP_SYS_NICE)) {
2283                         count = -EPERM;
2284                         goto out;
2285                 }
2286
2287                 err = security_task_setscheduler(p);
2288                 if (err) {
2289                         count = err;
2290                         goto out;
2291                 }
2292         }
2293
2294         task_lock(p);
2295         if (slack_ns == 0)
2296                 p->timer_slack_ns = p->default_timer_slack_ns;
2297         else
2298                 p->timer_slack_ns = slack_ns;
2299         task_unlock(p);
2300
2301 out:
2302         put_task_struct(p);
2303
2304         return count;
2305 }
2306
2307 static int timerslack_ns_show(struct seq_file *m, void *v)
2308 {
2309         struct inode *inode = m->private;
2310         struct task_struct *p;
2311         int err = 0;
2312
2313         p = get_proc_task(inode);
2314         if (!p)
2315                 return -ESRCH;
2316
2317         if (p != current) {
2318
2319                 if (!capable(CAP_SYS_NICE)) {
2320                         err = -EPERM;
2321                         goto out;
2322                 }
2323                 err = security_task_getscheduler(p);
2324                 if (err)
2325                         goto out;
2326         }
2327
2328         task_lock(p);
2329         seq_printf(m, "%llu\n", p->timer_slack_ns);
2330         task_unlock(p);
2331
2332 out:
2333         put_task_struct(p);
2334
2335         return err;
2336 }
2337
2338 static int timerslack_ns_open(struct inode *inode, struct file *filp)
2339 {
2340         return single_open(filp, timerslack_ns_show, inode);
2341 }
2342
2343 static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2344         .open           = timerslack_ns_open,
2345         .read           = seq_read,
2346         .write          = timerslack_ns_write,
2347         .llseek         = seq_lseek,
2348         .release        = single_release,
2349 };
2350
2351 static int proc_pident_instantiate(struct inode *dir,
2352         struct dentry *dentry, struct task_struct *task, const void *ptr)
2353 {
2354         const struct pid_entry *p = ptr;
2355         struct inode *inode;
2356         struct proc_inode *ei;
2357
2358         inode = proc_pid_make_inode(dir->i_sb, task, p->mode);
2359         if (!inode)
2360                 goto out;
2361
2362         ei = PROC_I(inode);
2363         if (S_ISDIR(inode->i_mode))
2364                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2365         if (p->iop)
2366                 inode->i_op = p->iop;
2367         if (p->fop)
2368                 inode->i_fop = p->fop;
2369         ei->op = p->op;
2370         d_set_d_op(dentry, &pid_dentry_operations);
2371         d_add(dentry, inode);
2372         /* Close the race of the process dying before we return the dentry */
2373         if (pid_revalidate(dentry, 0))
2374                 return 0;
2375 out:
2376         return -ENOENT;
2377 }
2378
2379 static struct dentry *proc_pident_lookup(struct inode *dir,
2380                                          struct dentry *dentry,
2381                                          const struct pid_entry *ents,
2382                                          unsigned int nents)
2383 {
2384         int error;
2385         struct task_struct *task = get_proc_task(dir);
2386         const struct pid_entry *p, *last;
2387
2388         error = -ENOENT;
2389
2390         if (!task)
2391                 goto out_no_task;
2392
2393         /*
2394          * Yes, it does not scale. And it should not. Don't add
2395          * new entries into /proc/<tgid>/ without very good reasons.
2396          */
2397         last = &ents[nents];
2398         for (p = ents; p < last; p++) {
2399                 if (p->len != dentry->d_name.len)
2400                         continue;
2401                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2402                         break;
2403         }
2404         if (p >= last)
2405                 goto out;
2406
2407         error = proc_pident_instantiate(dir, dentry, task, p);
2408 out:
2409         put_task_struct(task);
2410 out_no_task:
2411         return ERR_PTR(error);
2412 }
2413
2414 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2415                 const struct pid_entry *ents, unsigned int nents)
2416 {
2417         struct task_struct *task = get_proc_task(file_inode(file));
2418         const struct pid_entry *p;
2419
2420         if (!task)
2421                 return -ENOENT;
2422
2423         if (!dir_emit_dots(file, ctx))
2424                 goto out;
2425
2426         if (ctx->pos >= nents + 2)
2427                 goto out;
2428
2429         for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
2430                 if (!proc_fill_cache(file, ctx, p->name, p->len,
2431                                 proc_pident_instantiate, task, p))
2432                         break;
2433                 ctx->pos++;
2434         }
2435 out:
2436         put_task_struct(task);
2437         return 0;
2438 }
2439
2440 #ifdef CONFIG_SECURITY
2441 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2442                                   size_t count, loff_t *ppos)
2443 {
2444         struct inode * inode = file_inode(file);
2445         char *p = NULL;
2446         ssize_t length;
2447         struct task_struct *task = get_proc_task(inode);
2448
2449         if (!task)
2450                 return -ESRCH;
2451
2452         length = security_getprocattr(task,
2453                                       (char*)file->f_path.dentry->d_name.name,
2454                                       &p);
2455         put_task_struct(task);
2456         if (length > 0)
2457                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2458         kfree(p);
2459         return length;
2460 }
2461
2462 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2463                                    size_t count, loff_t *ppos)
2464 {
2465         struct inode * inode = file_inode(file);
2466         void *page;
2467         ssize_t length;
2468         struct task_struct *task = get_proc_task(inode);
2469
2470         length = -ESRCH;
2471         if (!task)
2472                 goto out_no_task;
2473
2474         /* A task may only write its own attributes. */
2475         length = -EACCES;
2476         if (current != task)
2477                 goto out;
2478
2479         if (count > PAGE_SIZE)
2480                 count = PAGE_SIZE;
2481
2482         /* No partial writes. */
2483         length = -EINVAL;
2484         if (*ppos != 0)
2485                 goto out;
2486
2487         page = memdup_user(buf, count);
2488         if (IS_ERR(page)) {
2489                 length = PTR_ERR(page);
2490                 goto out;
2491         }
2492
2493         /* Guard against adverse ptrace interaction */
2494         length = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
2495         if (length < 0)
2496                 goto out_free;
2497
2498         length = security_setprocattr(file->f_path.dentry->d_name.name,
2499                                       page, count);
2500         mutex_unlock(&current->signal->cred_guard_mutex);
2501 out_free:
2502         kfree(page);
2503 out:
2504         put_task_struct(task);
2505 out_no_task:
2506         return length;
2507 }
2508
2509 static const struct file_operations proc_pid_attr_operations = {
2510         .read           = proc_pid_attr_read,
2511         .write          = proc_pid_attr_write,
2512         .llseek         = generic_file_llseek,
2513 };
2514
2515 static const struct pid_entry attr_dir_stuff[] = {
2516         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2517         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2518         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2519         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2520         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2521         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2522 };
2523
2524 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2525 {
2526         return proc_pident_readdir(file, ctx,
2527                                    attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2528 }
2529
2530 static const struct file_operations proc_attr_dir_operations = {
2531         .read           = generic_read_dir,
2532         .iterate_shared = proc_attr_dir_readdir,
2533         .llseek         = generic_file_llseek,
2534 };
2535
2536 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2537                                 struct dentry *dentry, unsigned int flags)
2538 {
2539         return proc_pident_lookup(dir, dentry,
2540                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2541 }
2542
2543 static const struct inode_operations proc_attr_dir_inode_operations = {
2544         .lookup         = proc_attr_dir_lookup,
2545         .getattr        = pid_getattr,
2546         .setattr        = proc_setattr,
2547 };
2548
2549 #endif
2550
2551 #ifdef CONFIG_ELF_CORE
2552 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2553                                          size_t count, loff_t *ppos)
2554 {
2555         struct task_struct *task = get_proc_task(file_inode(file));
2556         struct mm_struct *mm;
2557         char buffer[PROC_NUMBUF];
2558         size_t len;
2559         int ret;
2560
2561         if (!task)
2562                 return -ESRCH;
2563
2564         ret = 0;
2565         mm = get_task_mm(task);
2566         if (mm) {
2567                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2568                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2569                                 MMF_DUMP_FILTER_SHIFT));
2570                 mmput(mm);
2571                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2572         }
2573
2574         put_task_struct(task);
2575
2576         return ret;
2577 }
2578
2579 static ssize_t proc_coredump_filter_write(struct file *file,
2580                                           const char __user *buf,
2581                                           size_t count,
2582                                           loff_t *ppos)
2583 {
2584         struct task_struct *task;
2585         struct mm_struct *mm;
2586         unsigned int val;
2587         int ret;
2588         int i;
2589         unsigned long mask;
2590
2591         ret = kstrtouint_from_user(buf, count, 0, &val);
2592         if (ret < 0)
2593                 return ret;
2594
2595         ret = -ESRCH;
2596         task = get_proc_task(file_inode(file));
2597         if (!task)
2598                 goto out_no_task;
2599
2600         mm = get_task_mm(task);
2601         if (!mm)
2602                 goto out_no_mm;
2603         ret = 0;
2604
2605         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2606                 if (val & mask)
2607                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2608                 else
2609                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2610         }
2611
2612         mmput(mm);
2613  out_no_mm:
2614         put_task_struct(task);
2615  out_no_task:
2616         if (ret < 0)
2617                 return ret;
2618         return count;
2619 }
2620
2621 static const struct file_operations proc_coredump_filter_operations = {
2622         .read           = proc_coredump_filter_read,
2623         .write          = proc_coredump_filter_write,
2624         .llseek         = generic_file_llseek,
2625 };
2626 #endif
2627
2628 #ifdef CONFIG_TASK_IO_ACCOUNTING
2629 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2630 {
2631         struct task_io_accounting acct = task->ioac;
2632         unsigned long flags;
2633         int result;
2634
2635         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2636         if (result)
2637                 return result;
2638
2639         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2640                 result = -EACCES;
2641                 goto out_unlock;
2642         }
2643
2644         if (whole && lock_task_sighand(task, &flags)) {
2645                 struct task_struct *t = task;
2646
2647                 task_io_accounting_add(&acct, &task->signal->ioac);
2648                 while_each_thread(task, t)
2649                         task_io_accounting_add(&acct, &t->ioac);
2650
2651                 unlock_task_sighand(task, &flags);
2652         }
2653         seq_printf(m,
2654                    "rchar: %llu\n"
2655                    "wchar: %llu\n"
2656                    "syscr: %llu\n"
2657                    "syscw: %llu\n"
2658                    "read_bytes: %llu\n"
2659                    "write_bytes: %llu\n"
2660                    "cancelled_write_bytes: %llu\n",
2661                    (unsigned long long)acct.rchar,
2662                    (unsigned long long)acct.wchar,
2663                    (unsigned long long)acct.syscr,
2664                    (unsigned long long)acct.syscw,
2665                    (unsigned long long)acct.read_bytes,
2666                    (unsigned long long)acct.write_bytes,
2667                    (unsigned long long)acct.cancelled_write_bytes);
2668         result = 0;
2669
2670 out_unlock:
2671         mutex_unlock(&task->signal->cred_guard_mutex);
2672         return result;
2673 }
2674
2675 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2676                                   struct pid *pid, struct task_struct *task)
2677 {
2678         return do_io_accounting(task, m, 0);
2679 }
2680
2681 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2682                                    struct pid *pid, struct task_struct *task)
2683 {
2684         return do_io_accounting(task, m, 1);
2685 }
2686 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2687
2688 #ifdef CONFIG_USER_NS
2689 static int proc_id_map_open(struct inode *inode, struct file *file,
2690         const struct seq_operations *seq_ops)
2691 {
2692         struct user_namespace *ns = NULL;
2693         struct task_struct *task;
2694         struct seq_file *seq;
2695         int ret = -EINVAL;
2696
2697         task = get_proc_task(inode);
2698         if (task) {
2699                 rcu_read_lock();
2700                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2701                 rcu_read_unlock();
2702                 put_task_struct(task);
2703         }
2704         if (!ns)
2705                 goto err;
2706
2707         ret = seq_open(file, seq_ops);
2708         if (ret)
2709                 goto err_put_ns;
2710
2711         seq = file->private_data;
2712         seq->private = ns;
2713
2714         return 0;
2715 err_put_ns:
2716         put_user_ns(ns);
2717 err:
2718         return ret;
2719 }
2720
2721 static int proc_id_map_release(struct inode *inode, struct file *file)
2722 {
2723         struct seq_file *seq = file->private_data;
2724         struct user_namespace *ns = seq->private;
2725         put_user_ns(ns);
2726         return seq_release(inode, file);
2727 }
2728
2729 static int proc_uid_map_open(struct inode *inode, struct file *file)
2730 {
2731         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2732 }
2733
2734 static int proc_gid_map_open(struct inode *inode, struct file *file)
2735 {
2736         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2737 }
2738
2739 static int proc_projid_map_open(struct inode *inode, struct file *file)
2740 {
2741         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2742 }
2743
2744 static const struct file_operations proc_uid_map_operations = {
2745         .open           = proc_uid_map_open,
2746         .write          = proc_uid_map_write,
2747         .read           = seq_read,
2748         .llseek         = seq_lseek,
2749         .release        = proc_id_map_release,
2750 };
2751
2752 static const struct file_operations proc_gid_map_operations = {
2753         .open           = proc_gid_map_open,
2754         .write          = proc_gid_map_write,
2755         .read           = seq_read,
2756         .llseek         = seq_lseek,
2757         .release        = proc_id_map_release,
2758 };
2759
2760 static const struct file_operations proc_projid_map_operations = {
2761         .open           = proc_projid_map_open,
2762         .write          = proc_projid_map_write,
2763         .read           = seq_read,
2764         .llseek         = seq_lseek,
2765         .release        = proc_id_map_release,
2766 };
2767
2768 static int proc_setgroups_open(struct inode *inode, struct file *file)
2769 {
2770         struct user_namespace *ns = NULL;
2771         struct task_struct *task;
2772         int ret;
2773
2774         ret = -ESRCH;
2775         task = get_proc_task(inode);
2776         if (task) {
2777                 rcu_read_lock();
2778                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2779                 rcu_read_unlock();
2780                 put_task_struct(task);
2781         }
2782         if (!ns)
2783                 goto err;
2784
2785         if (file->f_mode & FMODE_WRITE) {
2786                 ret = -EACCES;
2787                 if (!ns_capable(ns, CAP_SYS_ADMIN))
2788                         goto err_put_ns;
2789         }
2790
2791         ret = single_open(file, &proc_setgroups_show, ns);
2792         if (ret)
2793                 goto err_put_ns;
2794
2795         return 0;
2796 err_put_ns:
2797         put_user_ns(ns);
2798 err:
2799         return ret;
2800 }
2801
2802 static int proc_setgroups_release(struct inode *inode, struct file *file)
2803 {
2804         struct seq_file *seq = file->private_data;
2805         struct user_namespace *ns = seq->private;
2806         int ret = single_release(inode, file);
2807         put_user_ns(ns);
2808         return ret;
2809 }
2810
2811 static const struct file_operations proc_setgroups_operations = {
2812         .open           = proc_setgroups_open,
2813         .write          = proc_setgroups_write,
2814         .read           = seq_read,
2815         .llseek         = seq_lseek,
2816         .release        = proc_setgroups_release,
2817 };
2818 #endif /* CONFIG_USER_NS */
2819
2820 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2821                                 struct pid *pid, struct task_struct *task)
2822 {
2823         int err = lock_trace(task);
2824         if (!err) {
2825                 seq_printf(m, "%08x\n", task->personality);
2826                 unlock_trace(task);
2827         }
2828         return err;
2829 }
2830
2831 /*
2832  * Thread groups
2833  */
2834 static const struct file_operations proc_task_operations;
2835 static const struct inode_operations proc_task_inode_operations;
2836
2837 static const struct pid_entry tgid_base_stuff[] = {
2838         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2839         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2840         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2841         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2842         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2843 #ifdef CONFIG_NET
2844         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2845 #endif
2846         REG("environ",    S_IRUSR, proc_environ_operations),
2847         REG("auxv",       S_IRUSR, proc_auxv_operations),
2848         ONE("status",     S_IRUGO, proc_pid_status),
2849         ONE("personality", S_IRUSR, proc_pid_personality),
2850         ONE("limits",     S_IRUGO, proc_pid_limits),
2851 #ifdef CONFIG_SCHED_DEBUG
2852         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2853 #endif
2854 #ifdef CONFIG_SCHED_AUTOGROUP
2855         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2856 #endif
2857         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2858 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2859         ONE("syscall",    S_IRUSR, proc_pid_syscall),
2860 #endif
2861         REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
2862         ONE("stat",       S_IRUGO, proc_tgid_stat),
2863         ONE("statm",      S_IRUGO, proc_pid_statm),
2864         REG("maps",       S_IRUGO, proc_pid_maps_operations),
2865 #ifdef CONFIG_NUMA
2866         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2867 #endif
2868         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2869         LNK("cwd",        proc_cwd_link),
2870         LNK("root",       proc_root_link),
2871         LNK("exe",        proc_exe_link),
2872         REG("mounts",     S_IRUGO, proc_mounts_operations),
2873         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2874         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2875 #ifdef CONFIG_PROC_PAGE_MONITOR
2876         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2877         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2878         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2879 #endif
2880 #ifdef CONFIG_SECURITY
2881         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2882 #endif
2883 #ifdef CONFIG_KALLSYMS
2884         ONE("wchan",      S_IRUGO, proc_pid_wchan),
2885 #endif
2886 #ifdef CONFIG_STACKTRACE
2887         ONE("stack",      S_IRUSR, proc_pid_stack),
2888 #endif
2889 #ifdef CONFIG_SCHED_INFO
2890         ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
2891 #endif
2892 #ifdef CONFIG_LATENCYTOP
2893         REG("latency",  S_IRUGO, proc_lstats_operations),
2894 #endif
2895 #ifdef CONFIG_PROC_PID_CPUSET
2896         ONE("cpuset",     S_IRUGO, proc_cpuset_show),
2897 #endif
2898 #ifdef CONFIG_CGROUPS
2899         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
2900 #endif
2901         ONE("oom_score",  S_IRUGO, proc_oom_score),
2902         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
2903         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2904 #ifdef CONFIG_AUDITSYSCALL
2905         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2906         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2907 #endif
2908 #ifdef CONFIG_FAULT_INJECTION
2909         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2910 #endif
2911 #ifdef CONFIG_ELF_CORE
2912         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2913 #endif
2914 #ifdef CONFIG_TASK_IO_ACCOUNTING
2915         ONE("io",       S_IRUSR, proc_tgid_io_accounting),
2916 #endif
2917 #ifdef CONFIG_HARDWALL
2918         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
2919 #endif
2920 #ifdef CONFIG_USER_NS
2921         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
2922         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
2923         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
2924         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
2925 #endif
2926 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2927         REG("timers",     S_IRUGO, proc_timers_operations),
2928 #endif
2929         REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
2930 };
2931
2932 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
2933 {
2934         return proc_pident_readdir(file, ctx,
2935                                    tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2936 }
2937
2938 static const struct file_operations proc_tgid_base_operations = {
2939         .read           = generic_read_dir,
2940         .iterate_shared = proc_tgid_base_readdir,
2941         .llseek         = generic_file_llseek,
2942 };
2943
2944 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
2945 {
2946         return proc_pident_lookup(dir, dentry,
2947                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2948 }
2949
2950 static const struct inode_operations proc_tgid_base_inode_operations = {
2951         .lookup         = proc_tgid_base_lookup,
2952         .getattr        = pid_getattr,
2953         .setattr        = proc_setattr,
2954         .permission     = proc_pid_permission,
2955 };
2956
2957 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2958 {
2959         struct dentry *dentry, *leader, *dir;
2960         char buf[PROC_NUMBUF];
2961         struct qstr name;
2962
2963         name.name = buf;
2964         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2965         /* no ->d_hash() rejects on procfs */
2966         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2967         if (dentry) {
2968                 d_invalidate(dentry);
2969                 dput(dentry);
2970         }
2971
2972         if (pid == tgid)
2973                 return;
2974
2975         name.name = buf;
2976         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2977         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2978         if (!leader)
2979                 goto out;
2980
2981         name.name = "task";
2982         name.len = strlen(name.name);
2983         dir = d_hash_and_lookup(leader, &name);
2984         if (!dir)
2985                 goto out_put_leader;
2986
2987         name.name = buf;
2988         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2989         dentry = d_hash_and_lookup(dir, &name);
2990         if (dentry) {
2991                 d_invalidate(dentry);
2992                 dput(dentry);
2993         }
2994
2995         dput(dir);
2996 out_put_leader:
2997         dput(leader);
2998 out:
2999         return;
3000 }
3001
3002 /**
3003  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
3004  * @task: task that should be flushed.
3005  *
3006  * When flushing dentries from proc, one needs to flush them from global
3007  * proc (proc_mnt) and from all the namespaces' procs this task was seen
3008  * in. This call is supposed to do all of this job.
3009  *
3010  * Looks in the dcache for
3011  * /proc/@pid
3012  * /proc/@tgid/task/@pid
3013  * if either directory is present flushes it and all of it'ts children
3014  * from the dcache.
3015  *
3016  * It is safe and reasonable to cache /proc entries for a task until
3017  * that task exits.  After that they just clog up the dcache with
3018  * useless entries, possibly causing useful dcache entries to be
3019  * flushed instead.  This routine is proved to flush those useless
3020  * dcache entries at process exit time.
3021  *
3022  * NOTE: This routine is just an optimization so it does not guarantee
3023  *       that no dcache entries will exist at process exit time it
3024  *       just makes it very unlikely that any will persist.
3025  */
3026
3027 void proc_flush_task(struct task_struct *task)
3028 {
3029         int i;
3030         struct pid *pid, *tgid;
3031         struct upid *upid;
3032
3033         pid = task_pid(task);
3034         tgid = task_tgid(task);
3035
3036         for (i = 0; i <= pid->level; i++) {
3037                 upid = &pid->numbers[i];
3038                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3039                                         tgid->numbers[i].nr);
3040         }
3041 }
3042
3043 static int proc_pid_instantiate(struct inode *dir,
3044                                    struct dentry * dentry,
3045                                    struct task_struct *task, const void *ptr)
3046 {
3047         struct inode *inode;
3048
3049         inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3050         if (!inode)
3051                 goto out;
3052
3053         inode->i_op = &proc_tgid_base_inode_operations;
3054         inode->i_fop = &proc_tgid_base_operations;
3055         inode->i_flags|=S_IMMUTABLE;
3056
3057         set_nlink(inode, nlink_tgid);
3058
3059         d_set_d_op(dentry, &pid_dentry_operations);
3060
3061         d_add(dentry, inode);
3062         /* Close the race of the process dying before we return the dentry */
3063         if (pid_revalidate(dentry, 0))
3064                 return 0;
3065 out:
3066         return -ENOENT;
3067 }
3068
3069 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3070 {
3071         int result = -ENOENT;
3072         struct task_struct *task;
3073         unsigned tgid;
3074         struct pid_namespace *ns;
3075
3076         tgid = name_to_int(&dentry->d_name);
3077         if (tgid == ~0U)
3078                 goto out;
3079
3080         ns = dentry->d_sb->s_fs_info;
3081         rcu_read_lock();
3082         task = find_task_by_pid_ns(tgid, ns);
3083         if (task)
3084                 get_task_struct(task);
3085         rcu_read_unlock();
3086         if (!task)
3087                 goto out;
3088
3089         result = proc_pid_instantiate(dir, dentry, task, NULL);
3090         put_task_struct(task);
3091 out:
3092         return ERR_PTR(result);
3093 }
3094
3095 /*
3096  * Find the first task with tgid >= tgid
3097  *
3098  */
3099 struct tgid_iter {
3100         unsigned int tgid;
3101         struct task_struct *task;
3102 };
3103 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3104 {
3105         struct pid *pid;
3106
3107         if (iter.task)
3108                 put_task_struct(iter.task);
3109         rcu_read_lock();
3110 retry:
3111         iter.task = NULL;
3112         pid = find_ge_pid(iter.tgid, ns);
3113         if (pid) {
3114                 iter.tgid = pid_nr_ns(pid, ns);
3115                 iter.task = pid_task(pid, PIDTYPE_PID);
3116                 /* What we to know is if the pid we have find is the
3117                  * pid of a thread_group_leader.  Testing for task
3118                  * being a thread_group_leader is the obvious thing
3119                  * todo but there is a window when it fails, due to
3120                  * the pid transfer logic in de_thread.
3121                  *
3122                  * So we perform the straight forward test of seeing
3123                  * if the pid we have found is the pid of a thread
3124                  * group leader, and don't worry if the task we have
3125                  * found doesn't happen to be a thread group leader.
3126                  * As we don't care in the case of readdir.
3127                  */
3128                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3129                         iter.tgid += 1;
3130                         goto retry;
3131                 }
3132                 get_task_struct(iter.task);
3133         }
3134         rcu_read_unlock();
3135         return iter;
3136 }
3137
3138 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3139
3140 /* for the /proc/ directory itself, after non-process stuff has been done */
3141 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3142 {
3143         struct tgid_iter iter;
3144         struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info;
3145         loff_t pos = ctx->pos;
3146
3147         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3148                 return 0;
3149
3150         if (pos == TGID_OFFSET - 2) {
3151                 struct inode *inode = d_inode(ns->proc_self);
3152                 if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3153                         return 0;
3154                 ctx->pos = pos = pos + 1;
3155         }
3156         if (pos == TGID_OFFSET - 1) {
3157                 struct inode *inode = d_inode(ns->proc_thread_self);
3158                 if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3159                         return 0;
3160                 ctx->pos = pos = pos + 1;
3161         }
3162         iter.tgid = pos - TGID_OFFSET;
3163         iter.task = NULL;
3164         for (iter = next_tgid(ns, iter);
3165              iter.task;
3166              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3167                 char name[PROC_NUMBUF];
3168                 int len;
3169
3170                 cond_resched();
3171                 if (!has_pid_permissions(ns, iter.task, HIDEPID_INVISIBLE))
3172                         continue;
3173
3174                 len = snprintf(name, sizeof(name), "%d", iter.tgid);
3175                 ctx->pos = iter.tgid + TGID_OFFSET;
3176                 if (!proc_fill_cache(file, ctx, name, len,
3177                                      proc_pid_instantiate, iter.task, NULL)) {
3178                         put_task_struct(iter.task);
3179                         return 0;
3180                 }
3181         }
3182         ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3183         return 0;
3184 }
3185
3186 /*
3187  * proc_tid_comm_permission is a special permission function exclusively
3188  * used for the node /proc/<pid>/task/<tid>/comm.
3189  * It bypasses generic permission checks in the case where a task of the same
3190  * task group attempts to access the node.
3191  * The rationale behind this is that glibc and bionic access this node for
3192  * cross thread naming (pthread_set/getname_np(!self)). However, if
3193  * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3194  * which locks out the cross thread naming implementation.
3195  * This function makes sure that the node is always accessible for members of
3196  * same thread group.
3197  */
3198 static int proc_tid_comm_permission(struct inode *inode, int mask)
3199 {
3200         bool is_same_tgroup;
3201         struct task_struct *task;
3202
3203         task = get_proc_task(inode);
3204         if (!task)
3205                 return -ESRCH;
3206         is_same_tgroup = same_thread_group(current, task);
3207         put_task_struct(task);
3208
3209         if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3210                 /* This file (/proc/<pid>/task/<tid>/comm) can always be
3211                  * read or written by the members of the corresponding
3212                  * thread group.
3213                  */
3214                 return 0;
3215         }
3216
3217         return generic_permission(inode, mask);
3218 }
3219
3220 static const struct inode_operations proc_tid_comm_inode_operations = {
3221                 .permission = proc_tid_comm_permission,
3222 };
3223
3224 /*
3225  * Tasks
3226  */
3227 static const struct pid_entry tid_base_stuff[] = {
3228         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3229         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3230         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3231 #ifdef CONFIG_NET
3232         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3233 #endif
3234         REG("environ",   S_IRUSR, proc_environ_operations),
3235         REG("auxv",      S_IRUSR, proc_auxv_operations),
3236         ONE("status",    S_IRUGO, proc_pid_status),
3237         ONE("personality", S_IRUSR, proc_pid_personality),
3238         ONE("limits",    S_IRUGO, proc_pid_limits),
3239 #ifdef CONFIG_SCHED_DEBUG
3240         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3241 #endif
3242         NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3243                          &proc_tid_comm_inode_operations,
3244                          &proc_pid_set_comm_operations, {}),
3245 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3246         ONE("syscall",   S_IRUSR, proc_pid_syscall),
3247 #endif
3248         REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3249         ONE("stat",      S_IRUGO, proc_tid_stat),
3250         ONE("statm",     S_IRUGO, proc_pid_statm),
3251         REG("maps",      S_IRUGO, proc_tid_maps_operations),
3252 #ifdef CONFIG_PROC_CHILDREN
3253         REG("children",  S_IRUGO, proc_tid_children_operations),
3254 #endif
3255 #ifdef CONFIG_NUMA
3256         REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3257 #endif
3258         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3259         LNK("cwd",       proc_cwd_link),
3260         LNK("root",      proc_root_link),
3261         LNK("exe",       proc_exe_link),
3262         REG("mounts",    S_IRUGO, proc_mounts_operations),
3263         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3264 #ifdef CONFIG_PROC_PAGE_MONITOR
3265         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3266         REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3267         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3268 #endif
3269 #ifdef CONFIG_SECURITY
3270         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3271 #endif
3272 #ifdef CONFIG_KALLSYMS
3273         ONE("wchan",     S_IRUGO, proc_pid_wchan),
3274 #endif
3275 #ifdef CONFIG_STACKTRACE
3276         ONE("stack",      S_IRUSR, proc_pid_stack),
3277 #endif
3278 #ifdef CONFIG_SCHED_INFO
3279         ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3280 #endif
3281 #ifdef CONFIG_LATENCYTOP
3282         REG("latency",  S_IRUGO, proc_lstats_operations),
3283 #endif
3284 #ifdef CONFIG_PROC_PID_CPUSET
3285         ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3286 #endif
3287 #ifdef CONFIG_CGROUPS
3288         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3289 #endif
3290         ONE("oom_score", S_IRUGO, proc_oom_score),
3291         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3292         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3293 #ifdef CONFIG_AUDITSYSCALL
3294         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3295         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3296 #endif
3297 #ifdef CONFIG_FAULT_INJECTION
3298         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3299 #endif
3300 #ifdef CONFIG_TASK_IO_ACCOUNTING
3301         ONE("io",       S_IRUSR, proc_tid_io_accounting),
3302 #endif
3303 #ifdef CONFIG_HARDWALL
3304         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
3305 #endif
3306 #ifdef CONFIG_USER_NS
3307         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3308         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3309         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3310         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3311 #endif
3312 };
3313
3314 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3315 {
3316         return proc_pident_readdir(file, ctx,
3317                                    tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3318 }
3319
3320 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3321 {
3322         return proc_pident_lookup(dir, dentry,
3323                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3324 }
3325
3326 static const struct file_operations proc_tid_base_operations = {
3327         .read           = generic_read_dir,
3328         .iterate_shared = proc_tid_base_readdir,
3329         .llseek         = generic_file_llseek,
3330 };
3331
3332 static const struct inode_operations proc_tid_base_inode_operations = {
3333         .lookup         = proc_tid_base_lookup,
3334         .getattr        = pid_getattr,
3335         .setattr        = proc_setattr,
3336 };
3337
3338 static int proc_task_instantiate(struct inode *dir,
3339         struct dentry *dentry, struct task_struct *task, const void *ptr)
3340 {
3341         struct inode *inode;
3342         inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3343
3344         if (!inode)
3345                 goto out;
3346         inode->i_op = &proc_tid_base_inode_operations;
3347         inode->i_fop = &proc_tid_base_operations;
3348         inode->i_flags|=S_IMMUTABLE;
3349
3350         set_nlink(inode, nlink_tid);
3351
3352         d_set_d_op(dentry, &pid_dentry_operations);
3353
3354         d_add(dentry, inode);
3355         /* Close the race of the process dying before we return the dentry */
3356         if (pid_revalidate(dentry, 0))
3357                 return 0;
3358 out:
3359         return -ENOENT;
3360 }
3361
3362 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3363 {
3364         int result = -ENOENT;
3365         struct task_struct *task;
3366         struct task_struct *leader = get_proc_task(dir);
3367         unsigned tid;
3368         struct pid_namespace *ns;
3369
3370         if (!leader)
3371                 goto out_no_task;
3372
3373         tid = name_to_int(&dentry->d_name);
3374         if (tid == ~0U)
3375                 goto out;
3376
3377         ns = dentry->d_sb->s_fs_info;
3378         rcu_read_lock();
3379         task = find_task_by_pid_ns(tid, ns);
3380         if (task)
3381                 get_task_struct(task);
3382         rcu_read_unlock();
3383         if (!task)
3384                 goto out;
3385         if (!same_thread_group(leader, task))
3386                 goto out_drop_task;
3387
3388         result = proc_task_instantiate(dir, dentry, task, NULL);
3389 out_drop_task:
3390         put_task_struct(task);
3391 out:
3392         put_task_struct(leader);
3393 out_no_task:
3394         return ERR_PTR(result);
3395 }
3396
3397 /*
3398  * Find the first tid of a thread group to return to user space.
3399  *
3400  * Usually this is just the thread group leader, but if the users
3401  * buffer was too small or there was a seek into the middle of the
3402  * directory we have more work todo.
3403  *
3404  * In the case of a short read we start with find_task_by_pid.
3405  *
3406  * In the case of a seek we start with the leader and walk nr
3407  * threads past it.
3408  */
3409 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3410                                         struct pid_namespace *ns)
3411 {
3412         struct task_struct *pos, *task;
3413         unsigned long nr = f_pos;
3414
3415         if (nr != f_pos)        /* 32bit overflow? */
3416                 return NULL;
3417
3418         rcu_read_lock();
3419         task = pid_task(pid, PIDTYPE_PID);
3420         if (!task)
3421                 goto fail;
3422
3423         /* Attempt to start with the tid of a thread */
3424         if (tid && nr) {
3425                 pos = find_task_by_pid_ns(tid, ns);
3426                 if (pos && same_thread_group(pos, task))
3427                         goto found;
3428         }
3429
3430         /* If nr exceeds the number of threads there is nothing todo */
3431         if (nr >= get_nr_threads(task))
3432                 goto fail;
3433
3434         /* If we haven't found our starting place yet start
3435          * with the leader and walk nr threads forward.
3436          */
3437         pos = task = task->group_leader;
3438         do {
3439                 if (!nr--)
3440                         goto found;
3441         } while_each_thread(task, pos);
3442 fail:
3443         pos = NULL;
3444         goto out;
3445 found:
3446         get_task_struct(pos);
3447 out:
3448         rcu_read_unlock();
3449         return pos;
3450 }
3451
3452 /*
3453  * Find the next thread in the thread list.
3454  * Return NULL if there is an error or no next thread.
3455  *
3456  * The reference to the input task_struct is released.
3457  */
3458 static struct task_struct *next_tid(struct task_struct *start)
3459 {
3460         struct task_struct *pos = NULL;
3461         rcu_read_lock();
3462         if (pid_alive(start)) {
3463                 pos = next_thread(start);
3464                 if (thread_group_leader(pos))
3465                         pos = NULL;
3466                 else
3467                         get_task_struct(pos);
3468         }
3469         rcu_read_unlock();
3470         put_task_struct(start);
3471         return pos;
3472 }
3473
3474 /* for the /proc/TGID/task/ directories */
3475 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3476 {
3477         struct inode *inode = file_inode(file);
3478         struct task_struct *task;
3479         struct pid_namespace *ns;
3480         int tid;
3481
3482         if (proc_inode_is_dead(inode))
3483                 return -ENOENT;
3484
3485         if (!dir_emit_dots(file, ctx))
3486                 return 0;
3487
3488         /* f_version caches the tgid value that the last readdir call couldn't
3489          * return. lseek aka telldir automagically resets f_version to 0.
3490          */
3491         ns = inode->i_sb->s_fs_info;
3492         tid = (int)file->f_version;
3493         file->f_version = 0;
3494         for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3495              task;
3496              task = next_tid(task), ctx->pos++) {
3497                 char name[PROC_NUMBUF];
3498                 int len;
3499                 tid = task_pid_nr_ns(task, ns);
3500                 len = snprintf(name, sizeof(name), "%d", tid);
3501                 if (!proc_fill_cache(file, ctx, name, len,
3502                                 proc_task_instantiate, task, NULL)) {
3503                         /* returning this tgid failed, save it as the first
3504                          * pid for the next readir call */
3505                         file->f_version = (u64)tid;
3506                         put_task_struct(task);
3507                         break;
3508                 }
3509         }
3510
3511         return 0;
3512 }
3513
3514 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3515 {
3516         struct inode *inode = d_inode(dentry);
3517         struct task_struct *p = get_proc_task(inode);
3518         generic_fillattr(inode, stat);
3519
3520         if (p) {
3521                 stat->nlink += get_nr_threads(p);
3522                 put_task_struct(p);
3523         }
3524
3525         return 0;
3526 }
3527
3528 static const struct inode_operations proc_task_inode_operations = {
3529         .lookup         = proc_task_lookup,
3530         .getattr        = proc_task_getattr,
3531         .setattr        = proc_setattr,
3532         .permission     = proc_pid_permission,
3533 };
3534
3535 static const struct file_operations proc_task_operations = {
3536         .read           = generic_read_dir,
3537         .iterate_shared = proc_task_readdir,
3538         .llseek         = generic_file_llseek,
3539 };
3540
3541 void __init set_proc_pid_nlink(void)
3542 {
3543         nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3544         nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3545 }