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 <[email protected]>
  20  *  Edjard Mota <[email protected]>
  21  *  Ilias Biris <[email protected]>
  22  *  Mauricio Lin <[email protected]>
  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 <[email protected]>:
  44  *  Smaps information related to shared, private, clean and dirty pages.
  45  *
  46  *  Paul Mundt <[email protected]>:
  47  *  Overall revision about smaps.
  48  */
  49
  50 #include <asm/uaccess.h>
  51
  52 #include <linux/errno.h>
  53 #include <linux/time.h>
  54 #include <linux/proc_fs.h>
  55 #include <linux/stat.h>
  56 #include <linux/task_io_accounting_ops.h>
  57 #include <linux/init.h>
  58 #include <linux/capability.h>
  59 #include <linux/file.h>
  60 #include <linux/fdtable.h>
  61 #include <linux/string.h>
  62 #include <linux/seq_file.h>
  63 #include <linux/namei.h>
  64 #include <linux/mnt_namespace.h>
  65 #include <linux/mm.h>
  66 #include <linux/swap.h>
  67 #include <linux/rcupdate.h>
  68 #include <linux/kallsyms.h>
  69 #include <linux/stacktrace.h>
  70 #include <linux/resource.h>
  71 #include <linux/module.h>
  72 #include <linux/mount.h>
  73 #include <linux/security.h>
  74 #include <linux/ptrace.h>
  75 #include <linux/tracehook.h>
  76 #include <linux/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 struct pid_entry {
 108         const char *name;
 109         int len;
 110         umode_t mode;
 111         const struct inode_operations *iop;
 112         const struct file_operations *fop;
 113         union proc_op op;
 114 };
 115
 116 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 117         .name = (NAME),                                 \
 118         .len  = sizeof(NAME) - 1,                       \
 119         .mode = MODE,                                   \
 120         .iop  = IOP,                                    \
 121         .fop  = FOP,                                    \
 122         .op   = OP,                                     \
 123 }
 124
 125 #define DIR(NAME, MODE, iops, fops)     \
 126         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 127 #define LNK(NAME, get_link)                                     \
 128         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 129                 &proc_pid_link_inode_operations, NULL,          \
 130                 { .proc_get_link = get_link } )
 131 #define REG(NAME, MODE, fops)                           \
 132         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 133 #define ONE(NAME, MODE, show)                           \
 134         NOD(NAME, (S_IFREG|(MODE)),                     \
 135                 NULL, &proc_single_file_operations,     \
 136                 { .proc_show = show } )
 137
 138 /*
 139  * Count the number of hardlinks for the pid_entry table, excluding the .
 140  * and .. links.
 141  */
 142 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
 143         unsigned int n)
 144 {
 145         unsigned int i;
 146         unsigned int count;
 147
 148         count = 0;
 149         for (i = 0; i < n; ++i) {
 150                 if (S_ISDIR(entries[i].mode))
 151                         ++count;
 152         }
 153
 154         return count;
 155 }
 156
 157 static int get_task_root(struct task_struct *task, struct path *root)
 158 {
 159         int result = -ENOENT;
 160
 161         task_lock(task);
 162         if (task->fs) {
 163                 get_fs_root(task->fs, root);
 164                 result = 0;
 165         }
 166         task_unlock(task);
 167         return result;
 168 }
 169
 170 static int proc_cwd_link(struct dentry *dentry, struct path *path)
 171 {
 172         struct task_struct *task = get_proc_task(d_inode(dentry));
 173         int result = -ENOENT;
 174
 175         if (task) {
 176                 task_lock(task);
 177                 if (task->fs) {
 178                         get_fs_pwd(task->fs, path);
 179                         result = 0;
 180                 }
 181                 task_unlock(task);
 182                 put_task_struct(task);
 183         }
 184         return result;
 185 }
 186
 187 static int proc_root_link(struct dentry *dentry, struct path *path)
 188 {
 189         struct task_struct *task = get_proc_task(d_inode(dentry));
 190         int result = -ENOENT;
 191
 192         if (task) {
 193                 result = get_task_root(task, path);
 194                 put_task_struct(task);
 195         }
 196         return result;
 197 }
 198
 199 static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 200                                      size_t _count, loff_t *pos)
 201 {
 202         struct task_struct *tsk;
 203         struct mm_struct *mm;
 204         char *page;
 205         unsigned long count = _count;
 206         unsigned long arg_start, arg_end, env_start, env_end;
 207         unsigned long len1, len2, len;
 208         unsigned long p;
 209         char c;
 210         ssize_t rv;
 211
 212         BUG_ON(*pos < 0);
 213
 214         tsk = get_proc_task(file_inode(file));
 215         if (!tsk)
 216                 return -ESRCH;
 217         mm = get_task_mm(tsk);
 218         put_task_struct(tsk);
 219         if (!mm)
 220                 return 0;
 221         /* Check if process spawned far enough to have cmdline. */
 222         if (!mm->env_end) {
 223                 rv = 0;
 224                 goto out_mmput;
 225         }
 226
 227         page = (char *)__get_free_page(GFP_TEMPORARY);
 228         if (!page) {
 229                 rv = -ENOMEM;
 230                 goto out_mmput;
 231         }
 232
 233         down_read(&mm->mmap_sem);
 234         arg_start = mm->arg_start;
 235         arg_end = mm->arg_end;
 236         env_start = mm->env_start;
 237         env_end = mm->env_end;
 238         up_read(&mm->mmap_sem);
 239
 240         BUG_ON(arg_start > arg_end);
 241         BUG_ON(env_start > env_end);
 242
 243         len1 = arg_end - arg_start;
 244         len2 = env_end - env_start;
 245
 246         /* Empty ARGV. */
 247         if (len1 == 0) {
 248                 rv = 0;
 249                 goto out_free_page;
 250         }
 251         /*
 252          * Inherently racy -- command line shares address space
 253          * with code and data.
 254          */
 255         rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0);
 256         if (rv <= 0)
 257                 goto out_free_page;
 258
 259         rv = 0;
 260
 261         if (c == '\0') {
 262                 /* Command line (set of strings) occupies whole ARGV. */
 263                 if (len1 <= *pos)
 264                         goto out_free_page;
 265
 266                 p = arg_start + *pos;
 267                 len = len1 - *pos;
 268                 while (count > 0 && len > 0) {
 269                         unsigned int _count;
 270                         int nr_read;
 271
 272                         _count = min3(count, len, PAGE_SIZE);
 273                         nr_read = access_remote_vm(mm, p, page, _count, 0);
 274                         if (nr_read < 0)
 275                                 rv = nr_read;
 276                         if (nr_read <= 0)
 277                                 goto out_free_page;
 278
 279                         if (copy_to_user(buf, page, nr_read)) {
 280                                 rv = -EFAULT;
 281                                 goto out_free_page;
 282                         }
 283
 284                         p       += nr_read;
 285                         len     -= nr_read;
 286                         buf     += nr_read;
 287                         count   -= nr_read;
 288                         rv      += nr_read;
 289                 }
 290         } else {
 291                 /*
 292                  * Command line (1 string) occupies ARGV and maybe
 293                  * extends into ENVP.
 294                  */
 295                 if (len1 + len2 <= *pos)
 296                         goto skip_argv_envp;
 297                 if (len1 <= *pos)
 298                         goto skip_argv;
 299
 300                 p = arg_start + *pos;
 301                 len = len1 - *pos;
 302                 while (count > 0 && len > 0) {
 303                         unsigned int _count, l;
 304                         int nr_read;
 305                         bool final;
 306
 307                         _count = min3(count, len, PAGE_SIZE);
 308                         nr_read = access_remote_vm(mm, p, page, _count, 0);
 309                         if (nr_read < 0)
 310                                 rv = nr_read;
 311                         if (nr_read <= 0)
 312                                 goto out_free_page;
 313
 314                         /*
 315                          * Command line can be shorter than whole ARGV
 316                          * even if last "marker" byte says it is not.
 317                          */
 318                         final = false;
 319                         l = strnlen(page, nr_read);
 320                         if (l < nr_read) {
 321                                 nr_read = l;
 322                                 final = true;
 323                         }
 324
 325                         if (copy_to_user(buf, page, nr_read)) {
 326                                 rv = -EFAULT;
 327                                 goto out_free_page;
 328                         }
 329
 330                         p       += nr_read;
 331                         len     -= nr_read;
 332                         buf     += nr_read;
 333                         count   -= nr_read;
 334                         rv      += nr_read;
 335
 336                         if (final)
 337                                 goto out_free_page;
 338                 }
 339 skip_argv:
 340                 /*
 341                  * Command line (1 string) occupies ARGV and
 342                  * extends into ENVP.
 343                  */
 344                 if (len1 <= *pos) {
 345                         p = env_start + *pos - len1;
 346                         len = len1 + len2 - *pos;
 347                 } else {
 348                         p = env_start;
 349                         len = len2;
 350                 }
 351                 while (count > 0 && len > 0) {
 352                         unsigned int _count, l;
 353                         int nr_read;
 354                         bool final;
 355
 356                         _count = min3(count, len, PAGE_SIZE);
 357                         nr_read = access_remote_vm(mm, p, page, _count, 0);
 358                         if (nr_read < 0)
 359                                 rv = nr_read;
 360                         if (nr_read <= 0)
 361                                 goto out_free_page;
 362
 363                         /* Find EOS. */
 364                         final = false;
 365                         l = strnlen(page, nr_read);
 366                         if (l < nr_read) {
 367                                 nr_read = l;
 368                                 final = true;
 369                         }
 370
 371                         if (copy_to_user(buf, page, nr_read)) {
 372                                 rv = -EFAULT;
 373                                 goto out_free_page;
 374                         }
 375
 376                         p       += nr_read;
 377                         len     -= nr_read;
 378                         buf     += nr_read;
 379                         count   -= nr_read;
 380                         rv      += nr_read;
 381
 382                         if (final)
 383                                 goto out_free_page;
 384                 }
 385 skip_argv_envp:
 386                 ;
 387         }
 388
 389 out_free_page:
 390         free_page((unsigned long)page);
 391 out_mmput:
 392         mmput(mm);
 393         if (rv > 0)
 394                 *pos += rv;
 395         return rv;
 396 }
 397
 398 static const struct file_operations proc_pid_cmdline_ops = {
 399         .read   = proc_pid_cmdline_read,
 400         .llseek = generic_file_llseek,
 401 };
 402
 403 static int proc_pid_auxv(struct seq_file *m, struct pid_namespace *ns,
 404                          struct pid *pid, struct task_struct *task)
 405 {
 406         struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
 407         if (mm && !IS_ERR(mm)) {
 408                 unsigned int nwords = 0;
 409                 do {
 410                         nwords += 2;
 411                 } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 412                 seq_write(m, mm->saved_auxv, nwords * sizeof(mm->saved_auxv[0]));
 413                 mmput(mm);
 414                 return 0;
 415         } else
 416                 return PTR_ERR(mm);
 417 }
 418
 419
 420 #ifdef CONFIG_KALLSYMS
 421 /*
 422  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 423  * Returns the resolved symbol.  If that fails, simply return the address.
 424  */
 425 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 426                           struct pid *pid, struct task_struct *task)
 427 {
 428         unsigned long wchan;
 429         char symname[KSYM_NAME_LEN];
 430
 431         wchan = get_wchan(task);
 432
 433         if (wchan && ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)
 434                         && !lookup_symbol_name(wchan, symname))
 435                 seq_printf(m, "%s", symname);
 436         else
 437                 seq_putc(m, '0');
 438
 439         return 0;
 440 }
 441 #endif /* CONFIG_KALLSYMS */
 442
 443 static int lock_trace(struct task_struct *task)
 444 {
 445         int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 446         if (err)
 447                 return err;
 448         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 449                 mutex_unlock(&task->signal->cred_guard_mutex);
 450                 return -EPERM;
 451         }
 452         return 0;
 453 }
 454
 455 static void unlock_trace(struct task_struct *task)
 456 {
 457         mutex_unlock(&task->signal->cred_guard_mutex);
 458 }
 459
 460 #ifdef CONFIG_STACKTRACE
 461
 462 #define MAX_STACK_TRACE_DEPTH   64
 463
 464 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 465                           struct pid *pid, struct task_struct *task)
 466 {
 467         struct stack_trace trace;
 468         unsigned long *entries;
 469         int err;
 470         int i;
 471
 472         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 473         if (!entries)
 474                 return -ENOMEM;
 475
 476         trace.nr_entries        = 0;
 477         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 478         trace.entries           = entries;
 479         trace.skip              = 0;
 480
 481         err = lock_trace(task);
 482         if (!err) {
 483                 save_stack_trace_tsk(task, &trace);
 484
 485                 for (i = 0; i < trace.nr_entries; i++) {
 486                         seq_printf(m, "[<%pK>] %pS\n",
 487                                    (void *)entries[i], (void *)entries[i]);
 488                 }
 489                 unlock_trace(task);
 490         }
 491         kfree(entries);
 492
 493         return err;
 494 }
 495 #endif
 496
 497 #ifdef CONFIG_SCHED_INFO
 498 /*
 499  * Provides /proc/PID/schedstat
 500  */
 501 static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 502                               struct pid *pid, struct task_struct *task)
 503 {
 504         if (unlikely(!sched_info_on()))
 505                 seq_printf(m, "0 0 0\n");
 506         else
 507                 seq_printf(m, "%llu %llu %lu\n",
 508                    (unsigned long long)task->se.sum_exec_runtime,
 509                    (unsigned long long)task->sched_info.run_delay,
 510                    task->sched_info.pcount);
 511
 512         return 0;
 513 }
 514 #endif
 515
 516 #ifdef CONFIG_LATENCYTOP
 517 static int lstats_show_proc(struct seq_file *m, void *v)
 518 {
 519         int i;
 520         struct inode *inode = m->private;
 521         struct task_struct *task = get_proc_task(inode);
 522
 523         if (!task)
 524                 return -ESRCH;
 525         seq_puts(m, "Latency Top version : v0.1\n");
 526         for (i = 0; i < 32; i++) {
 527                 struct latency_record *lr = &task->latency_record[i];
 528                 if (lr->backtrace[0]) {
 529                         int q;
 530                         seq_printf(m, "%i %li %li",
 531                                    lr->count, lr->time, lr->max);
 532                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 533                                 unsigned long bt = lr->backtrace[q];
 534                                 if (!bt)
 535                                         break;
 536                                 if (bt == ULONG_MAX)
 537                                         break;
 538                                 seq_printf(m, " %ps", (void *)bt);
 539                         }
 540                         seq_putc(m, '\n');
 541                 }
 542
 543         }
 544         put_task_struct(task);
 545         return 0;
 546 }
 547
 548 static int lstats_open(struct inode *inode, struct file *file)
 549 {
 550         return single_open(file, lstats_show_proc, inode);
 551 }
 552
 553 static ssize_t lstats_write(struct file *file, const char __user *buf,
 554                             size_t count, loff_t *offs)
 555 {
 556         struct task_struct *task = get_proc_task(file_inode(file));
 557
 558         if (!task)
 559                 return -ESRCH;
 560         clear_all_latency_tracing(task);
 561         put_task_struct(task);
 562
 563         return count;
 564 }
 565
 566 static const struct file_operations proc_lstats_operations = {
 567         .open           = lstats_open,
 568         .read           = seq_read,
 569         .write          = lstats_write,
 570         .llseek         = seq_lseek,
 571         .release        = single_release,
 572 };
 573
 574 #endif
 575
 576 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 577                           struct pid *pid, struct task_struct *task)
 578 {
 579         unsigned long totalpages = totalram_pages + total_swap_pages;
 580         unsigned long points = 0;
 581
 582         read_lock(&tasklist_lock);
 583         if (pid_alive(task))
 584                 points = oom_badness(task, NULL, NULL, totalpages) *
 585                                                 1000 / totalpages;
 586         read_unlock(&tasklist_lock);
 587         seq_printf(m, "%lu\n", points);
 588
 589         return 0;
 590 }
 591
 592 struct limit_names {
 593         const char *name;
 594         const char *unit;
 595 };
 596
 597 static const struct limit_names lnames[RLIM_NLIMITS] = {
 598         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 599         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 600         [RLIMIT_DATA] = {"Max data size", "bytes"},
 601         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 602         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 603         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 604         [RLIMIT_NPROC] = {"Max processes", "processes"},
 605         [RLIMIT_NOFILE] = {"Max open files", "files"},
 606         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 607         [RLIMIT_AS] = {"Max address space", "bytes"},
 608         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 609         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 610         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 611         [RLIMIT_NICE] = {"Max nice priority", NULL},
 612         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 613         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 614 };
 615
 616 /* Display limits for a process */
 617 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 618                            struct pid *pid, struct task_struct *task)
 619 {
 620         unsigned int i;
 621         unsigned long flags;
 622
 623         struct rlimit rlim[RLIM_NLIMITS];
 624
 625         if (!lock_task_sighand(task, &flags))
 626                 return 0;
 627         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 628         unlock_task_sighand(task, &flags);
 629
 630         /*
 631          * print the file header
 632          */
 633        seq_printf(m, "%-25s %-20s %-20s %-10s\n",
 634                   "Limit", "Soft Limit", "Hard Limit", "Units");
 635
 636         for (i = 0; i < RLIM_NLIMITS; i++) {
 637                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 638                         seq_printf(m, "%-25s %-20s ",
 639                                    lnames[i].name, "unlimited");
 640                 else
 641                         seq_printf(m, "%-25s %-20lu ",
 642                                    lnames[i].name, rlim[i].rlim_cur);
 643
 644                 if (rlim[i].rlim_max == RLIM_INFINITY)
 645                         seq_printf(m, "%-20s ", "unlimited");
 646                 else
 647                         seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 648
 649                 if (lnames[i].unit)
 650                         seq_printf(m, "%-10s\n", lnames[i].unit);
 651                 else
 652                         seq_putc(m, '\n');
 653         }
 654
 655         return 0;
 656 }
 657
 658 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 659 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 660                             struct pid *pid, struct task_struct *task)
 661 {
 662         long nr;
 663         unsigned long args[6], sp, pc;
 664         int res;
 665
 666         res = lock_trace(task);
 667         if (res)
 668                 return res;
 669
 670         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 671                 seq_puts(m, "running\n");
 672         else if (nr < 0)
 673                 seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 674         else
 675                 seq_printf(m,
 676                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 677                        nr,
 678                        args[0], args[1], args[2], args[3], args[4], args[5],
 679                        sp, pc);
 680         unlock_trace(task);
 681
 682         return 0;
 683 }
 684 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 685
 686 /************************************************************************/
 687 /*                       Here the fs part begins                        */
 688 /************************************************************************/
 689
 690 /* permission checks */
 691 static int proc_fd_access_allowed(struct inode *inode)
 692 {
 693         struct task_struct *task;
 694         int allowed = 0;
 695         /* Allow access to a task's file descriptors if it is us or we
 696          * may use ptrace attach to the process and find out that
 697          * information.
 698          */
 699         task = get_proc_task(inode);
 700         if (task) {
 701                 allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 702                 put_task_struct(task);
 703         }
 704         return allowed;
 705 }
 706
 707 int proc_setattr(struct dentry *dentry, struct iattr *attr)
 708 {
 709         int error;
 710         struct inode *inode = d_inode(dentry);
 711
 712         if (attr->ia_valid & ATTR_MODE)
 713                 return -EPERM;
 714
 715         error = inode_change_ok(inode, attr);
 716         if (error)
 717                 return error;
 718
 719         setattr_copy(inode, attr);
 720         mark_inode_dirty(inode);
 721         return 0;
 722 }
 723
 724 /*
 725  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 726  * or euid/egid (for hide_pid_min=2)?
 727  */
 728 static bool has_pid_permissions(struct pid_namespace *pid,
 729                                  struct task_struct *task,
 730                                  int hide_pid_min)
 731 {
 732         if (pid->hide_pid < hide_pid_min)
 733                 return true;
 734         if (in_group_p(pid->pid_gid))
 735                 return true;
 736         return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 737 }
 738
 739
 740 static int proc_pid_permission(struct inode *inode, int mask)
 741 {
 742         struct pid_namespace *pid = inode->i_sb->s_fs_info;
 743         struct task_struct *task;
 744         bool has_perms;
 745
 746         task = get_proc_task(inode);
 747         if (!task)
 748                 return -ESRCH;
 749         has_perms = has_pid_permissions(pid, task, 1);
 750         put_task_struct(task);
 751
 752         if (!has_perms) {
 753                 if (pid->hide_pid == 2) {
 754                         /*
 755                          * Let's make getdents(), stat(), and open()
 756                          * consistent with each other.  If a process
 757                          * may not stat() a file, it shouldn't be seen
 758                          * in procfs at all.
 759                          */
 760                         return -ENOENT;
 761                 }
 762
 763                 return -EPERM;
 764         }
 765         return generic_permission(inode, mask);
 766 }
 767
 768
 769
 770 static const struct inode_operations proc_def_inode_operations = {
 771         .setattr        = proc_setattr,
 772 };
 773
 774 static int proc_single_show(struct seq_file *m, void *v)
 775 {
 776         struct inode *inode = m->private;
 777         struct pid_namespace *ns;
 778         struct pid *pid;
 779         struct task_struct *task;
 780         int ret;
 781
 782         ns = inode->i_sb->s_fs_info;
 783         pid = proc_pid(inode);
 784         task = get_pid_task(pid, PIDTYPE_PID);
 785         if (!task)
 786                 return -ESRCH;
 787
 788         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 789
 790         put_task_struct(task);
 791         return ret;
 792 }
 793
 794 static int proc_single_open(struct inode *inode, struct file *filp)
 795 {
 796         return single_open(filp, proc_single_show, inode);
 797 }
 798
 799 static const struct file_operations proc_single_file_operations = {
 800         .open           = proc_single_open,
 801         .read           = seq_read,
 802         .llseek         = seq_lseek,
 803         .release        = single_release,
 804 };
 805
 806
 807 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 808 {
 809         struct task_struct *task = get_proc_task(inode);
 810         struct mm_struct *mm = ERR_PTR(-ESRCH);
 811
 812         if (task) {
 813                 mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 814                 put_task_struct(task);
 815
 816                 if (!IS_ERR_OR_NULL(mm)) {
 817                         /* ensure this mm_struct can't be freed */
 818                         atomic_inc(&mm->mm_count);
 819                         /* but do not pin its memory */
 820                         mmput(mm);
 821                 }
 822         }
 823
 824         return mm;
 825 }
 826
 827 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 828 {
 829         struct mm_struct *mm = proc_mem_open(inode, mode);
 830
 831         if (IS_ERR(mm))
 832                 return PTR_ERR(mm);
 833
 834         file->private_data = mm;
 835         return 0;
 836 }
 837
 838 static int mem_open(struct inode *inode, struct file *file)
 839 {
 840         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 841
 842         /* OK to pass negative loff_t, we can catch out-of-range */
 843         file->f_mode |= FMODE_UNSIGNED_OFFSET;
 844
 845         return ret;
 846 }
 847
 848 static ssize_t mem_rw(struct file *file, char __user *buf,
 849                         size_t count, loff_t *ppos, int write)
 850 {
 851         struct mm_struct *mm = file->private_data;
 852         unsigned long addr = *ppos;
 853         ssize_t copied;
 854         char *page;
 855
 856         if (!mm)
 857                 return 0;
 858
 859         page = (char *)__get_free_page(GFP_TEMPORARY);
 860         if (!page)
 861                 return -ENOMEM;
 862
 863         copied = 0;
 864         if (!atomic_inc_not_zero(&mm->mm_users))
 865                 goto free;
 866
 867         while (count > 0) {
 868                 int this_len = min_t(int, count, PAGE_SIZE);
 869
 870                 if (write && copy_from_user(page, buf, this_len)) {
 871                         copied = -EFAULT;
 872                         break;
 873                 }
 874
 875                 this_len = access_remote_vm(mm, addr, page, this_len, write);
 876                 if (!this_len) {
 877                         if (!copied)
 878                                 copied = -EIO;
 879                         break;
 880                 }
 881
 882                 if (!write && copy_to_user(buf, page, this_len)) {
 883                         copied = -EFAULT;
 884                         break;
 885                 }
 886
 887                 buf += this_len;
 888                 addr += this_len;
 889                 copied += this_len;
 890                 count -= this_len;
 891         }
 892         *ppos = addr;
 893
 894         mmput(mm);
 895 free:
 896         free_page((unsigned long) page);
 897         return copied;
 898 }
 899
 900 static ssize_t mem_read(struct file *file, char __user *buf,
 901                         size_t count, loff_t *ppos)
 902 {
 903         return mem_rw(file, buf, count, ppos, 0);
 904 }
 905
 906 static ssize_t mem_write(struct file *file, const char __user *buf,
 907                          size_t count, loff_t *ppos)
 908 {
 909         return mem_rw(file, (char __user*)buf, count, ppos, 1);
 910 }
 911
 912 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 913 {
 914         switch (orig) {
 915         case 0:
 916                 file->f_pos = offset;
 917                 break;
 918         case 1:
 919                 file->f_pos += offset;
 920                 break;
 921         default:
 922                 return -EINVAL;
 923         }
 924         force_successful_syscall_return();
 925         return file->f_pos;
 926 }
 927
 928 static int mem_release(struct inode *inode, struct file *file)
 929 {
 930         struct mm_struct *mm = file->private_data;
 931         if (mm)
 932                 mmdrop(mm);
 933         return 0;
 934 }
 935
 936 static const struct file_operations proc_mem_operations = {
 937         .llseek         = mem_lseek,
 938         .read           = mem_read,
 939         .write          = mem_write,
 940         .open           = mem_open,
 941         .release        = mem_release,
 942 };
 943
 944 static int environ_open(struct inode *inode, struct file *file)
 945 {
 946         return __mem_open(inode, file, PTRACE_MODE_READ);
 947 }
 948
 949 static ssize_t environ_read(struct file *file, char __user *buf,
 950                         size_t count, loff_t *ppos)
 951 {
 952         char *page;
 953         unsigned long src = *ppos;
 954         int ret = 0;
 955         struct mm_struct *mm = file->private_data;
 956         unsigned long env_start, env_end;
 957
 958         /* Ensure the process spawned far enough to have an environment. */
 959         if (!mm || !mm->env_end)
 960                 return 0;
 961
 962         page = (char *)__get_free_page(GFP_TEMPORARY);
 963         if (!page)
 964                 return -ENOMEM;
 965
 966         ret = 0;
 967         if (!atomic_inc_not_zero(&mm->mm_users))
 968                 goto free;
 969
 970         down_read(&mm->mmap_sem);
 971         env_start = mm->env_start;
 972         env_end = mm->env_end;
 973         up_read(&mm->mmap_sem);
 974
 975         while (count > 0) {
 976                 size_t this_len, max_len;
 977                 int retval;
 978
 979                 if (src >= (env_end - env_start))
 980                         break;
 981
 982                 this_len = env_end - (env_start + src);
 983
 984                 max_len = min_t(size_t, PAGE_SIZE, count);
 985                 this_len = min(max_len, this_len);
 986
 987                 retval = access_remote_vm(mm, (env_start + src),
 988                         page, this_len, 0);
 989
 990                 if (retval <= 0) {
 991                         ret = retval;
 992                         break;
 993                 }
 994
 995                 if (copy_to_user(buf, page, retval)) {
 996                         ret = -EFAULT;
 997                         break;
 998                 }
 999
1000                 ret += retval;
1001                 src += retval;
1002                 buf += retval;
1003                 count -= retval;
1004         }
1005         *ppos = src;
1006         mmput(mm);
1007
1008 free:
1009         free_page((unsigned long) page);
1010         return ret;
1011 }
1012
1013 static const struct file_operations proc_environ_operations = {
1014         .open           = environ_open,
1015         .read           = environ_read,
1016         .llseek         = generic_file_llseek,
1017         .release        = mem_release,
1018 };
1019
1020 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1021                             loff_t *ppos)
1022 {
1023         struct task_struct *task = get_proc_task(file_inode(file));
1024         char buffer[PROC_NUMBUF];
1025         int oom_adj = OOM_ADJUST_MIN;
1026         size_t len;
1027         unsigned long flags;
1028
1029         if (!task)
1030                 return -ESRCH;
1031         if (lock_task_sighand(task, &flags)) {
1032                 if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1033                         oom_adj = OOM_ADJUST_MAX;
1034                 else
1035                         oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1036                                   OOM_SCORE_ADJ_MAX;
1037                 unlock_task_sighand(task, &flags);
1038         }
1039         put_task_struct(task);
1040         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1041         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1042 }
1043
1044 /*
1045  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1046  * kernels.  The effective policy is defined by oom_score_adj, which has a
1047  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1048  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1049  * Processes that become oom disabled via oom_adj will still be oom disabled
1050  * with this implementation.
1051  *
1052  * oom_adj cannot be removed since existing userspace binaries use it.
1053  */
1054 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1055                              size_t count, loff_t *ppos)
1056 {
1057         struct task_struct *task;
1058         char buffer[PROC_NUMBUF];
1059         int oom_adj;
1060         unsigned long flags;
1061         int err;
1062
1063         memset(buffer, 0, sizeof(buffer));
1064         if (count > sizeof(buffer) - 1)
1065                 count = sizeof(buffer) - 1;
1066         if (copy_from_user(buffer, buf, count)) {
1067                 err = -EFAULT;
1068                 goto out;
1069         }
1070
1071         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1072         if (err)
1073                 goto out;
1074         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1075              oom_adj != OOM_DISABLE) {
1076                 err = -EINVAL;
1077                 goto out;
1078         }
1079
1080         task = get_proc_task(file_inode(file));
1081         if (!task) {
1082                 err = -ESRCH;
1083                 goto out;
1084         }
1085
1086         task_lock(task);
1087         if (!task->mm) {
1088                 err = -EINVAL;
1089                 goto err_task_lock;
1090         }
1091
1092         if (!lock_task_sighand(task, &flags)) {
1093                 err = -ESRCH;
1094                 goto err_task_lock;
1095         }
1096
1097         /*
1098          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1099          * value is always attainable.
1100          */
1101         if (oom_adj == OOM_ADJUST_MAX)
1102                 oom_adj = OOM_SCORE_ADJ_MAX;
1103         else
1104                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1105
1106         if (oom_adj < task->signal->oom_score_adj &&
1107             !capable(CAP_SYS_RESOURCE)) {
1108                 err = -EACCES;
1109                 goto err_sighand;
1110         }
1111
1112         /*
1113          * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1114          * /proc/pid/oom_score_adj instead.
1115          */
1116         pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1117                   current->comm, task_pid_nr(current), task_pid_nr(task),
1118                   task_pid_nr(task));
1119
1120         task->signal->oom_score_adj = oom_adj;
1121         trace_oom_score_adj_update(task);
1122 err_sighand:
1123         unlock_task_sighand(task, &flags);
1124 err_task_lock:
1125         task_unlock(task);
1126         put_task_struct(task);
1127 out:
1128         return err < 0 ? err : count;
1129 }
1130
1131 static const struct file_operations proc_oom_adj_operations = {
1132         .read           = oom_adj_read,
1133         .write          = oom_adj_write,
1134         .llseek         = generic_file_llseek,
1135 };
1136
1137 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1138                                         size_t count, loff_t *ppos)
1139 {
1140         struct task_struct *task = get_proc_task(file_inode(file));
1141         char buffer[PROC_NUMBUF];
1142         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1143         unsigned long flags;
1144         size_t len;
1145
1146         if (!task)
1147                 return -ESRCH;
1148         if (lock_task_sighand(task, &flags)) {
1149                 oom_score_adj = task->signal->oom_score_adj;
1150                 unlock_task_sighand(task, &flags);
1151         }
1152         put_task_struct(task);
1153         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1154         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1155 }
1156
1157 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1158                                         size_t count, loff_t *ppos)
1159 {
1160         struct task_struct *task;
1161         char buffer[PROC_NUMBUF];
1162         unsigned long flags;
1163         int oom_score_adj;
1164         int err;
1165
1166         memset(buffer, 0, sizeof(buffer));
1167         if (count > sizeof(buffer) - 1)
1168                 count = sizeof(buffer) - 1;
1169         if (copy_from_user(buffer, buf, count)) {
1170                 err = -EFAULT;
1171                 goto out;
1172         }
1173
1174         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1175         if (err)
1176                 goto out;
1177         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1178                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1179                 err = -EINVAL;
1180                 goto out;
1181         }
1182
1183         task = get_proc_task(file_inode(file));
1184         if (!task) {
1185                 err = -ESRCH;
1186                 goto out;
1187         }
1188
1189         task_lock(task);
1190         if (!task->mm) {
1191                 err = -EINVAL;
1192                 goto err_task_lock;
1193         }
1194
1195         if (!lock_task_sighand(task, &flags)) {
1196                 err = -ESRCH;
1197                 goto err_task_lock;
1198         }
1199
1200         if ((short)oom_score_adj < task->signal->oom_score_adj_min &&
1201                         !capable(CAP_SYS_RESOURCE)) {
1202                 err = -EACCES;
1203                 goto err_sighand;
1204         }
1205
1206         task->signal->oom_score_adj = (short)oom_score_adj;
1207         if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1208                 task->signal->oom_score_adj_min = (short)oom_score_adj;
1209         trace_oom_score_adj_update(task);
1210
1211 err_sighand:
1212         unlock_task_sighand(task, &flags);
1213 err_task_lock:
1214         task_unlock(task);
1215         put_task_struct(task);
1216 out:
1217         return err < 0 ? err : count;
1218 }
1219
1220 static const struct file_operations proc_oom_score_adj_operations = {
1221         .read           = oom_score_adj_read,
1222         .write          = oom_score_adj_write,
1223         .llseek         = default_llseek,
1224 };
1225
1226 #ifdef CONFIG_AUDITSYSCALL
1227 #define TMPBUFLEN 21
1228 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1229                                   size_t count, loff_t *ppos)
1230 {
1231         struct inode * inode = file_inode(file);
1232         struct task_struct *task = get_proc_task(inode);
1233         ssize_t length;
1234         char tmpbuf[TMPBUFLEN];
1235
1236         if (!task)
1237                 return -ESRCH;
1238         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1239                            from_kuid(file->f_cred->user_ns,
1240                                      audit_get_loginuid(task)));
1241         put_task_struct(task);
1242         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1243 }
1244
1245 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1246                                    size_t count, loff_t *ppos)
1247 {
1248         struct inode * inode = file_inode(file);
1249         uid_t loginuid;
1250         kuid_t kloginuid;
1251         int rv;
1252
1253         rcu_read_lock();
1254         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1255                 rcu_read_unlock();
1256                 return -EPERM;
1257         }
1258         rcu_read_unlock();
1259
1260         if (*ppos != 0) {
1261                 /* No partial writes. */
1262                 return -EINVAL;
1263         }
1264
1265         rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1266         if (rv < 0)
1267                 return rv;
1268
1269         /* is userspace tring to explicitly UNSET the loginuid? */
1270         if (loginuid == AUDIT_UID_UNSET) {
1271                 kloginuid = INVALID_UID;
1272         } else {
1273                 kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1274                 if (!uid_valid(kloginuid))
1275                         return -EINVAL;
1276         }
1277
1278         rv = audit_set_loginuid(kloginuid);
1279         if (rv < 0)
1280                 return rv;
1281         return count;
1282 }
1283
1284 static const struct file_operations proc_loginuid_operations = {
1285         .read           = proc_loginuid_read,
1286         .write          = proc_loginuid_write,
1287         .llseek         = generic_file_llseek,
1288 };
1289
1290 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1291                                   size_t count, loff_t *ppos)
1292 {
1293         struct inode * inode = file_inode(file);
1294         struct task_struct *task = get_proc_task(inode);
1295         ssize_t length;
1296         char tmpbuf[TMPBUFLEN];
1297
1298         if (!task)
1299                 return -ESRCH;
1300         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1301                                 audit_get_sessionid(task));
1302         put_task_struct(task);
1303         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1304 }
1305
1306 static const struct file_operations proc_sessionid_operations = {
1307         .read           = proc_sessionid_read,
1308         .llseek         = generic_file_llseek,
1309 };
1310 #endif
1311
1312 #ifdef CONFIG_FAULT_INJECTION
1313 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1314                                       size_t count, loff_t *ppos)
1315 {
1316         struct task_struct *task = get_proc_task(file_inode(file));
1317         char buffer[PROC_NUMBUF];
1318         size_t len;
1319         int make_it_fail;
1320
1321         if (!task)
1322                 return -ESRCH;
1323         make_it_fail = task->make_it_fail;
1324         put_task_struct(task);
1325
1326         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1327
1328         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1329 }
1330
1331 static ssize_t proc_fault_inject_write(struct file * file,
1332                         const char __user * buf, size_t count, loff_t *ppos)
1333 {
1334         struct task_struct *task;
1335         char buffer[PROC_NUMBUF];
1336         int make_it_fail;
1337         int rv;
1338
1339         if (!capable(CAP_SYS_RESOURCE))
1340                 return -EPERM;
1341         memset(buffer, 0, sizeof(buffer));
1342         if (count > sizeof(buffer) - 1)
1343                 count = sizeof(buffer) - 1;
1344         if (copy_from_user(buffer, buf, count))
1345                 return -EFAULT;
1346         rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1347         if (rv < 0)
1348                 return rv;
1349         if (make_it_fail < 0 || make_it_fail > 1)
1350                 return -EINVAL;
1351
1352         task = get_proc_task(file_inode(file));
1353         if (!task)
1354                 return -ESRCH;
1355         task->make_it_fail = make_it_fail;
1356         put_task_struct(task);
1357
1358         return count;
1359 }
1360
1361 static const struct file_operations proc_fault_inject_operations = {
1362         .read           = proc_fault_inject_read,
1363         .write          = proc_fault_inject_write,
1364         .llseek         = generic_file_llseek,
1365 };
1366 #endif
1367
1368
1369 #ifdef CONFIG_SCHED_DEBUG
1370 /*
1371  * Print out various scheduling related per-task fields:
1372  */
1373 static int sched_show(struct seq_file *m, void *v)
1374 {
1375         struct inode *inode = m->private;
1376         struct task_struct *p;
1377
1378         p = get_proc_task(inode);
1379         if (!p)
1380                 return -ESRCH;
1381         proc_sched_show_task(p, m);
1382
1383         put_task_struct(p);
1384
1385         return 0;
1386 }
1387
1388 static ssize_t
1389 sched_write(struct file *file, const char __user *buf,
1390             size_t count, loff_t *offset)
1391 {
1392         struct inode *inode = file_inode(file);
1393         struct task_struct *p;
1394
1395         p = get_proc_task(inode);
1396         if (!p)
1397                 return -ESRCH;
1398         proc_sched_set_task(p);
1399
1400         put_task_struct(p);
1401
1402         return count;
1403 }
1404
1405 static int sched_open(struct inode *inode, struct file *filp)
1406 {
1407         return single_open(filp, sched_show, inode);
1408 }
1409
1410 static const struct file_operations proc_pid_sched_operations = {
1411         .open           = sched_open,
1412         .read           = seq_read,
1413         .write          = sched_write,
1414         .llseek         = seq_lseek,
1415         .release        = single_release,
1416 };
1417
1418 #endif
1419
1420 #ifdef CONFIG_SCHED_AUTOGROUP
1421 /*
1422  * Print out autogroup related information:
1423  */
1424 static int sched_autogroup_show(struct seq_file *m, void *v)
1425 {
1426         struct inode *inode = m->private;
1427         struct task_struct *p;
1428
1429         p = get_proc_task(inode);
1430         if (!p)
1431                 return -ESRCH;
1432         proc_sched_autogroup_show_task(p, m);
1433
1434         put_task_struct(p);
1435
1436         return 0;
1437 }
1438
1439 static ssize_t
1440 sched_autogroup_write(struct file *file, const char __user *buf,
1441             size_t count, loff_t *offset)
1442 {
1443         struct inode *inode = file_inode(file);
1444         struct task_struct *p;
1445         char buffer[PROC_NUMBUF];
1446         int nice;
1447         int err;
1448
1449         memset(buffer, 0, sizeof(buffer));
1450         if (count > sizeof(buffer) - 1)
1451                 count = sizeof(buffer) - 1;
1452         if (copy_from_user(buffer, buf, count))
1453                 return -EFAULT;
1454
1455         err = kstrtoint(strstrip(buffer), 0, &nice);
1456         if (err < 0)
1457                 return err;
1458
1459         p = get_proc_task(inode);
1460         if (!p)
1461                 return -ESRCH;
1462
1463         err = proc_sched_autogroup_set_nice(p, nice);
1464         if (err)
1465                 count = err;
1466
1467         put_task_struct(p);
1468
1469         return count;
1470 }
1471
1472 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1473 {
1474         int ret;
1475
1476         ret = single_open(filp, sched_autogroup_show, NULL);
1477         if (!ret) {
1478                 struct seq_file *m = filp->private_data;
1479
1480                 m->private = inode;
1481         }
1482         return ret;
1483 }
1484
1485 static const struct file_operations proc_pid_sched_autogroup_operations = {
1486         .open           = sched_autogroup_open,
1487         .read           = seq_read,
1488         .write          = sched_autogroup_write,
1489         .llseek         = seq_lseek,
1490         .release        = single_release,
1491 };
1492
1493 #endif /* CONFIG_SCHED_AUTOGROUP */
1494
1495 static ssize_t comm_write(struct file *file, const char __user *buf,
1496                                 size_t count, loff_t *offset)
1497 {
1498         struct inode *inode = file_inode(file);
1499         struct task_struct *p;
1500         char buffer[TASK_COMM_LEN];
1501         const size_t maxlen = sizeof(buffer) - 1;
1502
1503         memset(buffer, 0, sizeof(buffer));
1504         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1505                 return -EFAULT;
1506
1507         p = get_proc_task(inode);
1508         if (!p)
1509                 return -ESRCH;
1510
1511         if (same_thread_group(current, p))
1512                 set_task_comm(p, buffer);
1513         else
1514                 count = -EINVAL;
1515
1516         put_task_struct(p);
1517
1518         return count;
1519 }
1520
1521 static int comm_show(struct seq_file *m, void *v)
1522 {
1523         struct inode *inode = m->private;
1524         struct task_struct *p;
1525
1526         p = get_proc_task(inode);
1527         if (!p)
1528                 return -ESRCH;
1529
1530         task_lock(p);
1531         seq_printf(m, "%s\n", p->comm);
1532         task_unlock(p);
1533
1534         put_task_struct(p);
1535
1536         return 0;
1537 }
1538
1539 static int comm_open(struct inode *inode, struct file *filp)
1540 {
1541         return single_open(filp, comm_show, inode);
1542 }
1543
1544 static const struct file_operations proc_pid_set_comm_operations = {
1545         .open           = comm_open,
1546         .read           = seq_read,
1547         .write          = comm_write,
1548         .llseek         = seq_lseek,
1549         .release        = single_release,
1550 };
1551
1552 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1553 {
1554         struct task_struct *task;
1555         struct mm_struct *mm;
1556         struct file *exe_file;
1557
1558         task = get_proc_task(d_inode(dentry));
1559         if (!task)
1560                 return -ENOENT;
1561         mm = get_task_mm(task);
1562         put_task_struct(task);
1563         if (!mm)
1564                 return -ENOENT;
1565         exe_file = get_mm_exe_file(mm);
1566         mmput(mm);
1567         if (exe_file) {
1568                 *exe_path = exe_file->f_path;
1569                 path_get(&exe_file->f_path);
1570                 fput(exe_file);
1571                 return 0;
1572         } else
1573                 return -ENOENT;
1574 }
1575
1576 static const char *proc_pid_get_link(struct dentry *dentry,
1577                                      struct inode *inode,
1578                                      struct delayed_call *done)
1579 {
1580         struct path path;
1581         int error = -EACCES;
1582
1583         if (!dentry)
1584                 return ERR_PTR(-ECHILD);
1585
1586         /* Are we allowed to snoop on the tasks file descriptors? */
1587         if (!proc_fd_access_allowed(inode))
1588                 goto out;
1589
1590         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1591         if (error)
1592                 goto out;
1593
1594         nd_jump_link(&path);
1595         return NULL;
1596 out:
1597         return ERR_PTR(error);
1598 }
1599
1600 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1601 {
1602         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1603         char *pathname;
1604         int len;
1605
1606         if (!tmp)
1607                 return -ENOMEM;
1608
1609         pathname = d_path(path, tmp, PAGE_SIZE);
1610         len = PTR_ERR(pathname);
1611         if (IS_ERR(pathname))
1612                 goto out;
1613         len = tmp + PAGE_SIZE - 1 - pathname;
1614
1615         if (len > buflen)
1616                 len = buflen;
1617         if (copy_to_user(buffer, pathname, len))
1618                 len = -EFAULT;
1619  out:
1620         free_page((unsigned long)tmp);
1621         return len;
1622 }
1623
1624 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1625 {
1626         int error = -EACCES;
1627         struct inode *inode = d_inode(dentry);
1628         struct path path;
1629
1630         /* Are we allowed to snoop on the tasks file descriptors? */
1631         if (!proc_fd_access_allowed(inode))
1632                 goto out;
1633
1634         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1635         if (error)
1636                 goto out;
1637
1638         error = do_proc_readlink(&path, buffer, buflen);
1639         path_put(&path);
1640 out:
1641         return error;
1642 }
1643
1644 const struct inode_operations proc_pid_link_inode_operations = {
1645         .readlink       = proc_pid_readlink,
1646         .get_link       = proc_pid_get_link,
1647         .setattr        = proc_setattr,
1648 };
1649
1650
1651 /* building an inode */
1652
1653 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1654 {
1655         struct inode * inode;
1656         struct proc_inode *ei;
1657         const struct cred *cred;
1658
1659         /* We need a new inode */
1660
1661         inode = new_inode(sb);
1662         if (!inode)
1663                 goto out;
1664
1665         /* Common stuff */
1666         ei = PROC_I(inode);
1667         inode->i_ino = get_next_ino();
1668         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1669         inode->i_op = &proc_def_inode_operations;
1670
1671         /*
1672          * grab the reference to task.
1673          */
1674         ei->pid = get_task_pid(task, PIDTYPE_PID);
1675         if (!ei->pid)
1676                 goto out_unlock;
1677
1678         if (task_dumpable(task)) {
1679                 rcu_read_lock();
1680                 cred = __task_cred(task);
1681                 inode->i_uid = cred->euid;
1682                 inode->i_gid = cred->egid;
1683                 rcu_read_unlock();
1684         }
1685         security_task_to_inode(task, inode);
1686
1687 out:
1688         return inode;
1689
1690 out_unlock:
1691         iput(inode);
1692         return NULL;
1693 }
1694
1695 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1696 {
1697         struct inode *inode = d_inode(dentry);
1698         struct task_struct *task;
1699         const struct cred *cred;
1700         struct pid_namespace *pid = dentry->d_sb->s_fs_info;
1701
1702         generic_fillattr(inode, stat);
1703
1704         rcu_read_lock();
1705         stat->uid = GLOBAL_ROOT_UID;
1706         stat->gid = GLOBAL_ROOT_GID;
1707         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1708         if (task) {
1709                 if (!has_pid_permissions(pid, task, 2)) {
1710                         rcu_read_unlock();
1711                         /*
1712                          * This doesn't prevent learning whether PID exists,
1713                          * it only makes getattr() consistent with readdir().
1714                          */
1715                         return -ENOENT;
1716                 }
1717                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1718                     task_dumpable(task)) {
1719                         cred = __task_cred(task);
1720                         stat->uid = cred->euid;
1721                         stat->gid = cred->egid;
1722                 }
1723         }
1724         rcu_read_unlock();
1725         return 0;
1726 }
1727
1728 /* dentry stuff */
1729
1730 /*
1731  *      Exceptional case: normally we are not allowed to unhash a busy
1732  * directory. In this case, however, we can do it - no aliasing problems
1733  * due to the way we treat inodes.
1734  *
1735  * Rewrite the inode's ownerships here because the owning task may have
1736  * performed a setuid(), etc.
1737  *
1738  * Before the /proc/pid/status file was created the only way to read
1739  * the effective uid of a /process was to stat /proc/pid.  Reading
1740  * /proc/pid/status is slow enough that procps and other packages
1741  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1742  * made this apply to all per process world readable and executable
1743  * directories.
1744  */
1745 int pid_revalidate(struct dentry *dentry, unsigned int flags)
1746 {
1747         struct inode *inode;
1748         struct task_struct *task;
1749         const struct cred *cred;
1750
1751         if (flags & LOOKUP_RCU)
1752                 return -ECHILD;
1753
1754         inode = d_inode(dentry);
1755         task = get_proc_task(inode);
1756
1757         if (task) {
1758                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1759                     task_dumpable(task)) {
1760                         rcu_read_lock();
1761                         cred = __task_cred(task);
1762                         inode->i_uid = cred->euid;
1763                         inode->i_gid = cred->egid;
1764                         rcu_read_unlock();
1765                 } else {
1766                         inode->i_uid = GLOBAL_ROOT_UID;
1767                         inode->i_gid = GLOBAL_ROOT_GID;
1768                 }
1769                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1770                 security_task_to_inode(task, inode);
1771                 put_task_struct(task);
1772                 return 1;
1773         }
1774         return 0;
1775 }
1776
1777 static inline bool proc_inode_is_dead(struct inode *inode)
1778 {
1779         return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1780 }
1781
1782 int pid_delete_dentry(const struct dentry *dentry)
1783 {
1784         /* Is the task we represent dead?
1785          * If so, then don't put the dentry on the lru list,
1786          * kill it immediately.
1787          */
1788         return proc_inode_is_dead(d_inode(dentry));
1789 }
1790
1791 const struct dentry_operations pid_dentry_operations =
1792 {
1793         .d_revalidate   = pid_revalidate,
1794         .d_delete       = pid_delete_dentry,
1795 };
1796
1797 /* Lookups */
1798
1799 /*
1800  * Fill a directory entry.
1801  *
1802  * If possible create the dcache entry and derive our inode number and
1803  * file type from dcache entry.
1804  *
1805  * Since all of the proc inode numbers are dynamically generated, the inode
1806  * numbers do not exist until the inode is cache.  This means creating the
1807  * the dcache entry in readdir is necessary to keep the inode numbers
1808  * reported by readdir in sync with the inode numbers reported
1809  * by stat.
1810  */
1811 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1812         const char *name, int len,
1813         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1814 {
1815         struct dentry *child, *dir = file->f_path.dentry;
1816         struct qstr qname = QSTR_INIT(name, len);
1817         struct inode *inode;
1818         unsigned type;
1819         ino_t ino;
1820
1821         child = d_hash_and_lookup(dir, &qname);
1822         if (!child) {
1823                 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1824                 child = d_alloc_parallel(dir, &qname, &wq);
1825                 if (IS_ERR(child))
1826                         goto end_instantiate;
1827                 if (d_in_lookup(child)) {
1828                         int err = instantiate(d_inode(dir), child, task, ptr);
1829                         d_lookup_done(child);
1830                         if (err < 0) {
1831                                 dput(child);
1832                                 goto end_instantiate;
1833                         }
1834                 }
1835         }
1836         inode = d_inode(child);
1837         ino = inode->i_ino;
1838         type = inode->i_mode >> 12;
1839         dput(child);
1840         return dir_emit(ctx, name, len, ino, type);
1841
1842 end_instantiate:
1843         return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
1844 }
1845
1846 /*
1847  * dname_to_vma_addr - maps a dentry name into two unsigned longs
1848  * which represent vma start and end addresses.
1849  */
1850 static int dname_to_vma_addr(struct dentry *dentry,
1851                              unsigned long *start, unsigned long *end)
1852 {
1853         if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
1854                 return -EINVAL;
1855
1856         return 0;
1857 }
1858
1859 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1860 {
1861         unsigned long vm_start, vm_end;
1862         bool exact_vma_exists = false;
1863         struct mm_struct *mm = NULL;
1864         struct task_struct *task;
1865         const struct cred *cred;
1866         struct inode *inode;
1867         int status = 0;
1868
1869         if (flags & LOOKUP_RCU)
1870                 return -ECHILD;
1871
1872         inode = d_inode(dentry);
1873         task = get_proc_task(inode);
1874         if (!task)
1875                 goto out_notask;
1876
1877         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1878         if (IS_ERR_OR_NULL(mm))
1879                 goto out;
1880
1881         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1882                 down_read(&mm->mmap_sem);
1883                 exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1884                 up_read(&mm->mmap_sem);
1885         }
1886
1887         mmput(mm);
1888
1889         if (exact_vma_exists) {
1890                 if (task_dumpable(task)) {
1891                         rcu_read_lock();
1892                         cred = __task_cred(task);
1893                         inode->i_uid = cred->euid;
1894                         inode->i_gid = cred->egid;
1895                         rcu_read_unlock();
1896                 } else {
1897                         inode->i_uid = GLOBAL_ROOT_UID;
1898                         inode->i_gid = GLOBAL_ROOT_GID;
1899                 }
1900                 security_task_to_inode(task, inode);
1901                 status = 1;
1902         }
1903
1904 out:
1905         put_task_struct(task);
1906
1907 out_notask:
1908         return status;
1909 }
1910
1911 static const struct dentry_operations tid_map_files_dentry_operations = {
1912         .d_revalidate   = map_files_d_revalidate,
1913         .d_delete       = pid_delete_dentry,
1914 };
1915
1916 static int map_files_get_link(struct dentry *dentry, struct path *path)
1917 {
1918         unsigned long vm_start, vm_end;
1919         struct vm_area_struct *vma;
1920         struct task_struct *task;
1921         struct mm_struct *mm;
1922         int rc;
1923
1924         rc = -ENOENT;
1925         task = get_proc_task(d_inode(dentry));
1926         if (!task)
1927                 goto out;
1928
1929         mm = get_task_mm(task);
1930         put_task_struct(task);
1931         if (!mm)
1932                 goto out;
1933
1934         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
1935         if (rc)
1936                 goto out_mmput;
1937
1938         rc = -ENOENT;
1939         down_read(&mm->mmap_sem);
1940         vma = find_exact_vma(mm, vm_start, vm_end);
1941         if (vma && vma->vm_file) {
1942                 *path = vma->vm_file->f_path;
1943                 path_get(path);
1944                 rc = 0;
1945         }
1946         up_read(&mm->mmap_sem);
1947
1948 out_mmput:
1949         mmput(mm);
1950 out:
1951         return rc;
1952 }
1953
1954 struct map_files_info {
1955         fmode_t         mode;
1956         unsigned long   len;
1957         unsigned char   name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
1958 };
1959
1960 /*
1961  * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
1962  * symlinks may be used to bypass permissions on ancestor directories in the
1963  * path to the file in question.
1964  */
1965 static const char *
1966 proc_map_files_get_link(struct dentry *dentry,
1967                         struct inode *inode,
1968                         struct delayed_call *done)
1969 {
1970         if (!capable(CAP_SYS_ADMIN))
1971                 return ERR_PTR(-EPERM);
1972
1973         return proc_pid_get_link(dentry, inode, done);
1974 }
1975
1976 /*
1977  * Identical to proc_pid_link_inode_operations except for get_link()
1978  */
1979 static const struct inode_operations proc_map_files_link_inode_operations = {
1980         .readlink       = proc_pid_readlink,
1981         .get_link       = proc_map_files_get_link,
1982         .setattr        = proc_setattr,
1983 };
1984
1985 static int
1986 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
1987                            struct task_struct *task, const void *ptr)
1988 {
1989         fmode_t mode = (fmode_t)(unsigned long)ptr;
1990         struct proc_inode *ei;
1991         struct inode *inode;
1992
1993         inode = proc_pid_make_inode(dir->i_sb, task);
1994         if (!inode)
1995                 return -ENOENT;
1996
1997         ei = PROC_I(inode);
1998         ei->op.proc_get_link = map_files_get_link;
1999
2000         inode->i_op = &proc_map_files_link_inode_operations;
2001         inode->i_size = 64;
2002         inode->i_mode = S_IFLNK;
2003
2004         if (mode & FMODE_READ)
2005                 inode->i_mode |= S_IRUSR;
2006         if (mode & FMODE_WRITE)
2007                 inode->i_mode |= S_IWUSR;
2008
2009         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2010         d_add(dentry, inode);
2011
2012         return 0;
2013 }
2014
2015 static struct dentry *proc_map_files_lookup(struct inode *dir,
2016                 struct dentry *dentry, unsigned int flags)
2017 {
2018         unsigned long vm_start, vm_end;
2019         struct vm_area_struct *vma;
2020         struct task_struct *task;
2021         int result;
2022         struct mm_struct *mm;
2023
2024         result = -ENOENT;
2025         task = get_proc_task(dir);
2026         if (!task)
2027                 goto out;
2028
2029         result = -EACCES;
2030         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2031                 goto out_put_task;
2032
2033         result = -ENOENT;
2034         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2035                 goto out_put_task;
2036
2037         mm = get_task_mm(task);
2038         if (!mm)
2039                 goto out_put_task;
2040
2041         down_read(&mm->mmap_sem);
2042         vma = find_exact_vma(mm, vm_start, vm_end);
2043         if (!vma)
2044                 goto out_no_vma;
2045
2046         if (vma->vm_file)
2047                 result = proc_map_files_instantiate(dir, dentry, task,
2048                                 (void *)(unsigned long)vma->vm_file->f_mode);
2049
2050 out_no_vma:
2051         up_read(&mm->mmap_sem);
2052         mmput(mm);
2053 out_put_task:
2054         put_task_struct(task);
2055 out:
2056         return ERR_PTR(result);
2057 }
2058
2059 static const struct inode_operations proc_map_files_inode_operations = {
2060         .lookup         = proc_map_files_lookup,
2061         .permission     = proc_fd_permission,
2062         .setattr        = proc_setattr,
2063 };
2064
2065 static int
2066 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2067 {
2068         struct vm_area_struct *vma;
2069         struct task_struct *task;
2070         struct mm_struct *mm;
2071         unsigned long nr_files, pos, i;
2072         struct flex_array *fa = NULL;
2073         struct map_files_info info;
2074         struct map_files_info *p;
2075         int ret;
2076
2077         ret = -ENOENT;
2078         task = get_proc_task(file_inode(file));
2079         if (!task)
2080                 goto out;
2081
2082         ret = -EACCES;
2083         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2084                 goto out_put_task;
2085
2086         ret = 0;
2087         if (!dir_emit_dots(file, ctx))
2088                 goto out_put_task;
2089
2090         mm = get_task_mm(task);
2091         if (!mm)
2092                 goto out_put_task;
2093         down_read(&mm->mmap_sem);
2094
2095         nr_files = 0;
2096
2097         /*
2098          * We need two passes here:
2099          *
2100          *  1) Collect vmas of mapped files with mmap_sem taken
2101          *  2) Release mmap_sem and instantiate entries
2102          *
2103          * otherwise we get lockdep complained, since filldir()
2104          * routine might require mmap_sem taken in might_fault().
2105          */
2106
2107         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2108                 if (vma->vm_file && ++pos > ctx->pos)
2109                         nr_files++;
2110         }
2111
2112         if (nr_files) {
2113                 fa = flex_array_alloc(sizeof(info), nr_files,
2114                                         GFP_KERNEL);
2115                 if (!fa || flex_array_prealloc(fa, 0, nr_files,
2116                                                 GFP_KERNEL)) {
2117                         ret = -ENOMEM;
2118                         if (fa)
2119                                 flex_array_free(fa);
2120                         up_read(&mm->mmap_sem);
2121                         mmput(mm);
2122                         goto out_put_task;
2123                 }
2124                 for (i = 0, vma = mm->mmap, pos = 2; vma;
2125                                 vma = vma->vm_next) {
2126                         if (!vma->vm_file)
2127                                 continue;
2128                         if (++pos <= ctx->pos)
2129                                 continue;
2130
2131                         info.mode = vma->vm_file->f_mode;
2132                         info.len = snprintf(info.name,
2133                                         sizeof(info.name), "%lx-%lx",
2134                                         vma->vm_start, vma->vm_end);
2135                         if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2136                                 BUG();
2137                 }
2138         }
2139         up_read(&mm->mmap_sem);
2140
2141         for (i = 0; i < nr_files; i++) {
2142                 p = flex_array_get(fa, i);
2143                 if (!proc_fill_cache(file, ctx,
2144                                       p->name, p->len,
2145                                       proc_map_files_instantiate,
2146                                       task,
2147                                       (void *)(unsigned long)p->mode))
2148                         break;
2149                 ctx->pos++;
2150         }
2151         if (fa)
2152                 flex_array_free(fa);
2153         mmput(mm);
2154
2155 out_put_task:
2156         put_task_struct(task);
2157 out:
2158         return ret;
2159 }
2160
2161 static const struct file_operations proc_map_files_operations = {
2162         .read           = generic_read_dir,
2163         .iterate_shared = proc_map_files_readdir,
2164         .llseek         = generic_file_llseek,
2165 };
2166
2167 #ifdef CONFIG_CHECKPOINT_RESTORE
2168 struct timers_private {
2169         struct pid *pid;
2170         struct task_struct *task;
2171         struct sighand_struct *sighand;
2172         struct pid_namespace *ns;
2173         unsigned long flags;
2174 };
2175
2176 static void *timers_start(struct seq_file *m, loff_t *pos)
2177 {
2178         struct timers_private *tp = m->private;
2179
2180         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2181         if (!tp->task)
2182                 return ERR_PTR(-ESRCH);
2183
2184         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2185         if (!tp->sighand)
2186                 return ERR_PTR(-ESRCH);
2187
2188         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2189 }
2190
2191 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2192 {
2193         struct timers_private *tp = m->private;
2194         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2195 }
2196
2197 static void timers_stop(struct seq_file *m, void *v)
2198 {
2199         struct timers_private *tp = m->private;
2200
2201         if (tp->sighand) {
2202                 unlock_task_sighand(tp->task, &tp->flags);
2203                 tp->sighand = NULL;
2204         }
2205
2206         if (tp->task) {
2207                 put_task_struct(tp->task);
2208                 tp->task = NULL;
2209         }
2210 }
2211
2212 static int show_timer(struct seq_file *m, void *v)
2213 {
2214         struct k_itimer *timer;
2215         struct timers_private *tp = m->private;
2216         int notify;
2217         static const char * const nstr[] = {
2218                 [SIGEV_SIGNAL] = "signal",
2219                 [SIGEV_NONE] = "none",
2220                 [SIGEV_THREAD] = "thread",
2221         };
2222
2223         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2224         notify = timer->it_sigev_notify;
2225
2226         seq_printf(m, "ID: %d\n", timer->it_id);
2227         seq_printf(m, "signal: %d/%p\n",
2228                    timer->sigq->info.si_signo,
2229                    timer->sigq->info.si_value.sival_ptr);
2230         seq_printf(m, "notify: %s/%s.%d\n",
2231                    nstr[notify & ~SIGEV_THREAD_ID],
2232                    (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2233                    pid_nr_ns(timer->it_pid, tp->ns));
2234         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2235
2236         return 0;
2237 }
2238
2239 static const struct seq_operations proc_timers_seq_ops = {
2240         .start  = timers_start,
2241         .next   = timers_next,
2242         .stop   = timers_stop,
2243         .show   = show_timer,
2244 };
2245
2246 static int proc_timers_open(struct inode *inode, struct file *file)
2247 {
2248         struct timers_private *tp;
2249
2250         tp = __seq_open_private(file, &proc_timers_seq_ops,
2251                         sizeof(struct timers_private));
2252         if (!tp)
2253                 return -ENOMEM;
2254
2255         tp->pid = proc_pid(inode);
2256         tp->ns = inode->i_sb->s_fs_info;
2257         return 0;
2258 }
2259
2260 static const struct file_operations proc_timers_operations = {
2261         .open           = proc_timers_open,
2262         .read           = seq_read,
2263         .llseek         = seq_lseek,
2264         .release        = seq_release_private,
2265 };
2266 #endif
2267
2268 static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2269                                         size_t count, loff_t *offset)
2270 {
2271         struct inode *inode = file_inode(file);
2272         struct task_struct *p;
2273         u64 slack_ns;
2274         int err;
2275
2276         err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2277         if (err < 0)
2278                 return err;
2279
2280         p = get_proc_task(inode);
2281         if (!p)
2282                 return -ESRCH;
2283
2284         if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) {
2285                 task_lock(p);
2286                 if (slack_ns == 0)
2287                         p->timer_slack_ns = p->default_timer_slack_ns;
2288                 else
2289                         p->timer_slack_ns = slack_ns;
2290                 task_unlock(p);
2291         } else
2292                 count = -EPERM;
2293
2294         put_task_struct(p);
2295
2296         return count;
2297 }
2298
2299 static int timerslack_ns_show(struct seq_file *m, void *v)
2300 {
2301         struct inode *inode = m->private;
2302         struct task_struct *p;
2303         int err =  0;
2304
2305         p = get_proc_task(inode);
2306         if (!p)
2307                 return -ESRCH;
2308
2309         if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) {
2310                 task_lock(p);
2311                 seq_printf(m, "%llu\n", p->timer_slack_ns);
2312                 task_unlock(p);
2313         } else
2314                 err = -EPERM;
2315
2316         put_task_struct(p);
2317
2318         return err;
2319 }
2320
2321 static int timerslack_ns_open(struct inode *inode, struct file *filp)
2322 {
2323         return single_open(filp, timerslack_ns_show, inode);
2324 }
2325
2326 static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2327         .open           = timerslack_ns_open,
2328         .read           = seq_read,
2329         .write          = timerslack_ns_write,
2330         .llseek         = seq_lseek,
2331         .release        = single_release,
2332 };
2333
2334 static int proc_pident_instantiate(struct inode *dir,
2335         struct dentry *dentry, struct task_struct *task, const void *ptr)
2336 {
2337         const struct pid_entry *p = ptr;
2338         struct inode *inode;
2339         struct proc_inode *ei;
2340
2341         inode = proc_pid_make_inode(dir->i_sb, task);
2342         if (!inode)
2343                 goto out;
2344
2345         ei = PROC_I(inode);
2346         inode->i_mode = p->mode;
2347         if (S_ISDIR(inode->i_mode))
2348                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2349         if (p->iop)
2350                 inode->i_op = p->iop;
2351         if (p->fop)
2352                 inode->i_fop = p->fop;
2353         ei->op = p->op;
2354         d_set_d_op(dentry, &pid_dentry_operations);
2355         d_add(dentry, inode);
2356         /* Close the race of the process dying before we return the dentry */
2357         if (pid_revalidate(dentry, 0))
2358                 return 0;
2359 out:
2360         return -ENOENT;
2361 }
2362
2363 static struct dentry *proc_pident_lookup(struct inode *dir,
2364                                          struct dentry *dentry,
2365                                          const struct pid_entry *ents,
2366                                          unsigned int nents)
2367 {
2368         int error;
2369         struct task_struct *task = get_proc_task(dir);
2370         const struct pid_entry *p, *last;
2371
2372         error = -ENOENT;
2373
2374         if (!task)
2375                 goto out_no_task;
2376
2377         /*
2378          * Yes, it does not scale. And it should not. Don't add
2379          * new entries into /proc/<tgid>/ without very good reasons.
2380          */
2381         last = &ents[nents - 1];
2382         for (p = ents; p <= last; p++) {
2383                 if (p->len != dentry->d_name.len)
2384                         continue;
2385                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2386                         break;
2387         }
2388         if (p > last)
2389                 goto out;
2390
2391         error = proc_pident_instantiate(dir, dentry, task, p);
2392 out:
2393         put_task_struct(task);
2394 out_no_task:
2395         return ERR_PTR(error);
2396 }
2397
2398 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2399                 const struct pid_entry *ents, unsigned int nents)
2400 {
2401         struct task_struct *task = get_proc_task(file_inode(file));
2402         const struct pid_entry *p;
2403
2404         if (!task)
2405                 return -ENOENT;
2406
2407         if (!dir_emit_dots(file, ctx))
2408                 goto out;
2409
2410         if (ctx->pos >= nents + 2)
2411                 goto out;
2412
2413         for (p = ents + (ctx->pos - 2); p <= ents + nents - 1; p++) {
2414                 if (!proc_fill_cache(file, ctx, p->name, p->len,
2415                                 proc_pident_instantiate, task, p))
2416                         break;
2417                 ctx->pos++;
2418         }
2419 out:
2420         put_task_struct(task);
2421         return 0;
2422 }
2423
2424 #ifdef CONFIG_SECURITY
2425 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2426                                   size_t count, loff_t *ppos)
2427 {
2428         struct inode * inode = file_inode(file);
2429         char *p = NULL;
2430         ssize_t length;
2431         struct task_struct *task = get_proc_task(inode);
2432
2433         if (!task)
2434                 return -ESRCH;
2435
2436         length = security_getprocattr(task,
2437                                       (char*)file->f_path.dentry->d_name.name,
2438                                       &p);
2439         put_task_struct(task);
2440         if (length > 0)
2441                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2442         kfree(p);
2443         return length;
2444 }
2445
2446 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2447                                    size_t count, loff_t *ppos)
2448 {
2449         struct inode * inode = file_inode(file);
2450         void *page;
2451         ssize_t length;
2452         struct task_struct *task = get_proc_task(inode);
2453
2454         length = -ESRCH;
2455         if (!task)
2456                 goto out_no_task;
2457         if (count > PAGE_SIZE)
2458                 count = PAGE_SIZE;
2459
2460         /* No partial writes. */
2461         length = -EINVAL;
2462         if (*ppos != 0)
2463                 goto out;
2464
2465         page = memdup_user(buf, count);
2466         if (IS_ERR(page)) {
2467                 length = PTR_ERR(page);
2468                 goto out;
2469         }
2470
2471         /* Guard against adverse ptrace interaction */
2472         length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2473         if (length < 0)
2474                 goto out_free;
2475
2476         length = security_setprocattr(task,
2477                                       (char*)file->f_path.dentry->d_name.name,
2478                                       page, count);
2479         mutex_unlock(&task->signal->cred_guard_mutex);
2480 out_free:
2481         kfree(page);
2482 out:
2483         put_task_struct(task);
2484 out_no_task:
2485         return length;
2486 }
2487
2488 static const struct file_operations proc_pid_attr_operations = {
2489         .read           = proc_pid_attr_read,
2490         .write          = proc_pid_attr_write,
2491         .llseek         = generic_file_llseek,
2492 };
2493
2494 static const struct pid_entry attr_dir_stuff[] = {
2495         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2496         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2497         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2498         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2499         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2500         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2501 };
2502
2503 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2504 {
2505         return proc_pident_readdir(file, ctx,
2506                                    attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2507 }
2508
2509 static const struct file_operations proc_attr_dir_operations = {
2510         .read           = generic_read_dir,
2511         .iterate_shared = proc_attr_dir_readdir,
2512         .llseek         = generic_file_llseek,
2513 };
2514
2515 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2516                                 struct dentry *dentry, unsigned int flags)
2517 {
2518         return proc_pident_lookup(dir, dentry,
2519                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2520 }
2521
2522 static const struct inode_operations proc_attr_dir_inode_operations = {
2523         .lookup         = proc_attr_dir_lookup,
2524         .getattr        = pid_getattr,
2525         .setattr        = proc_setattr,
2526 };
2527
2528 #endif
2529
2530 #ifdef CONFIG_ELF_CORE
2531 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2532                                          size_t count, loff_t *ppos)
2533 {
2534         struct task_struct *task = get_proc_task(file_inode(file));
2535         struct mm_struct *mm;
2536         char buffer[PROC_NUMBUF];
2537         size_t len;
2538         int ret;
2539
2540         if (!task)
2541                 return -ESRCH;
2542
2543         ret = 0;
2544         mm = get_task_mm(task);
2545         if (mm) {
2546                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2547                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2548                                 MMF_DUMP_FILTER_SHIFT));
2549                 mmput(mm);
2550                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2551         }
2552
2553         put_task_struct(task);
2554
2555         return ret;
2556 }
2557
2558 static ssize_t proc_coredump_filter_write(struct file *file,
2559                                           const char __user *buf,
2560                                           size_t count,
2561                                           loff_t *ppos)
2562 {
2563         struct task_struct *task;
2564         struct mm_struct *mm;
2565         unsigned int val;
2566         int ret;
2567         int i;
2568         unsigned long mask;
2569
2570         ret = kstrtouint_from_user(buf, count, 0, &val);
2571         if (ret < 0)
2572                 return ret;
2573
2574         ret = -ESRCH;
2575         task = get_proc_task(file_inode(file));
2576         if (!task)
2577                 goto out_no_task;
2578
2579         mm = get_task_mm(task);
2580         if (!mm)
2581                 goto out_no_mm;
2582         ret = 0;
2583
2584         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2585                 if (val & mask)
2586                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2587                 else
2588                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2589         }
2590
2591         mmput(mm);
2592  out_no_mm:
2593         put_task_struct(task);
2594  out_no_task:
2595         if (ret < 0)
2596                 return ret;
2597         return count;
2598 }
2599
2600 static const struct file_operations proc_coredump_filter_operations = {
2601         .read           = proc_coredump_filter_read,
2602         .write          = proc_coredump_filter_write,
2603         .llseek         = generic_file_llseek,
2604 };
2605 #endif
2606
2607 #ifdef CONFIG_TASK_IO_ACCOUNTING
2608 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2609 {
2610         struct task_io_accounting acct = task->ioac;
2611         unsigned long flags;
2612         int result;
2613
2614         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2615         if (result)
2616                 return result;
2617
2618         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2619                 result = -EACCES;
2620                 goto out_unlock;
2621         }
2622
2623         if (whole && lock_task_sighand(task, &flags)) {
2624                 struct task_struct *t = task;
2625
2626                 task_io_accounting_add(&acct, &task->signal->ioac);
2627                 while_each_thread(task, t)
2628                         task_io_accounting_add(&acct, &t->ioac);
2629
2630                 unlock_task_sighand(task, &flags);
2631         }
2632         seq_printf(m,
2633                    "rchar: %llu\n"
2634                    "wchar: %llu\n"
2635                    "syscr: %llu\n"
2636                    "syscw: %llu\n"
2637                    "read_bytes: %llu\n"
2638                    "write_bytes: %llu\n"
2639                    "cancelled_write_bytes: %llu\n",
2640                    (unsigned long long)acct.rchar,
2641                    (unsigned long long)acct.wchar,
2642                    (unsigned long long)acct.syscr,
2643                    (unsigned long long)acct.syscw,
2644                    (unsigned long long)acct.read_bytes,
2645                    (unsigned long long)acct.write_bytes,
2646                    (unsigned long long)acct.cancelled_write_bytes);
2647         result = 0;
2648
2649 out_unlock:
2650         mutex_unlock(&task->signal->cred_guard_mutex);
2651         return result;
2652 }
2653
2654 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2655                                   struct pid *pid, struct task_struct *task)
2656 {
2657         return do_io_accounting(task, m, 0);
2658 }
2659
2660 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2661                                    struct pid *pid, struct task_struct *task)
2662 {
2663         return do_io_accounting(task, m, 1);
2664 }
2665 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2666
2667 #ifdef CONFIG_USER_NS
2668 static int proc_id_map_open(struct inode *inode, struct file *file,
2669         const struct seq_operations *seq_ops)
2670 {
2671         struct user_namespace *ns = NULL;
2672         struct task_struct *task;
2673         struct seq_file *seq;
2674         int ret = -EINVAL;
2675
2676         task = get_proc_task(inode);
2677         if (task) {
2678                 rcu_read_lock();
2679                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2680                 rcu_read_unlock();
2681                 put_task_struct(task);
2682         }
2683         if (!ns)
2684                 goto err;
2685
2686         ret = seq_open(file, seq_ops);
2687         if (ret)
2688                 goto err_put_ns;
2689
2690         seq = file->private_data;
2691         seq->private = ns;
2692
2693         return 0;
2694 err_put_ns:
2695         put_user_ns(ns);
2696 err:
2697         return ret;
2698 }
2699
2700 static int proc_id_map_release(struct inode *inode, struct file *file)
2701 {
2702         struct seq_file *seq = file->private_data;
2703         struct user_namespace *ns = seq->private;
2704         put_user_ns(ns);
2705         return seq_release(inode, file);
2706 }
2707
2708 static int proc_uid_map_open(struct inode *inode, struct file *file)
2709 {
2710         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2711 }
2712
2713 static int proc_gid_map_open(struct inode *inode, struct file *file)
2714 {
2715         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2716 }
2717
2718 static int proc_projid_map_open(struct inode *inode, struct file *file)
2719 {
2720         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2721 }
2722
2723 static const struct file_operations proc_uid_map_operations = {
2724         .open           = proc_uid_map_open,
2725         .write          = proc_uid_map_write,
2726         .read           = seq_read,
2727         .llseek         = seq_lseek,
2728         .release        = proc_id_map_release,
2729 };
2730
2731 static const struct file_operations proc_gid_map_operations = {
2732         .open           = proc_gid_map_open,
2733         .write          = proc_gid_map_write,
2734         .read           = seq_read,
2735         .llseek         = seq_lseek,
2736         .release        = proc_id_map_release,
2737 };
2738
2739 static const struct file_operations proc_projid_map_operations = {
2740         .open           = proc_projid_map_open,
2741         .write          = proc_projid_map_write,
2742         .read           = seq_read,
2743         .llseek         = seq_lseek,
2744         .release        = proc_id_map_release,
2745 };
2746
2747 static int proc_setgroups_open(struct inode *inode, struct file *file)
2748 {
2749         struct user_namespace *ns = NULL;
2750         struct task_struct *task;
2751         int ret;
2752
2753         ret = -ESRCH;
2754         task = get_proc_task(inode);
2755         if (task) {
2756                 rcu_read_lock();
2757                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2758                 rcu_read_unlock();
2759                 put_task_struct(task);
2760         }
2761         if (!ns)
2762                 goto err;
2763
2764         if (file->f_mode & FMODE_WRITE) {
2765                 ret = -EACCES;
2766                 if (!ns_capable(ns, CAP_SYS_ADMIN))
2767                         goto err_put_ns;
2768         }
2769
2770         ret = single_open(file, &proc_setgroups_show, ns);
2771         if (ret)
2772                 goto err_put_ns;
2773
2774         return 0;
2775 err_put_ns:
2776         put_user_ns(ns);
2777 err:
2778         return ret;
2779 }
2780
2781 static int proc_setgroups_release(struct inode *inode, struct file *file)
2782 {
2783         struct seq_file *seq = file->private_data;
2784         struct user_namespace *ns = seq->private;
2785         int ret = single_release(inode, file);
2786         put_user_ns(ns);
2787         return ret;
2788 }
2789
2790 static const struct file_operations proc_setgroups_operations = {
2791         .open           = proc_setgroups_open,
2792         .write          = proc_setgroups_write,
2793         .read           = seq_read,
2794         .llseek         = seq_lseek,
2795         .release        = proc_setgroups_release,
2796 };
2797 #endif /* CONFIG_USER_NS */
2798
2799 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2800                                 struct pid *pid, struct task_struct *task)
2801 {
2802         int err = lock_trace(task);
2803         if (!err) {
2804                 seq_printf(m, "%08x\n", task->personality);
2805                 unlock_trace(task);
2806         }
2807         return err;
2808 }
2809
2810 /*
2811  * Thread groups
2812  */
2813 static const struct file_operations proc_task_operations;
2814 static const struct inode_operations proc_task_inode_operations;
2815
2816 static const struct pid_entry tgid_base_stuff[] = {
2817         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2818         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2819         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2820         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2821         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2822 #ifdef CONFIG_NET
2823         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2824 #endif
2825         REG("environ",    S_IRUSR, proc_environ_operations),
2826         ONE("auxv",       S_IRUSR, proc_pid_auxv),
2827         ONE("status",     S_IRUGO, proc_pid_status),
2828         ONE("personality", S_IRUSR, proc_pid_personality),
2829         ONE("limits",     S_IRUGO, proc_pid_limits),
2830 #ifdef CONFIG_SCHED_DEBUG
2831         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2832 #endif
2833 #ifdef CONFIG_SCHED_AUTOGROUP
2834         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2835 #endif
2836         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2837 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2838         ONE("syscall",    S_IRUSR, proc_pid_syscall),
2839 #endif
2840         REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
2841         ONE("stat",       S_IRUGO, proc_tgid_stat),
2842         ONE("statm",      S_IRUGO, proc_pid_statm),
2843         REG("maps",       S_IRUGO, proc_pid_maps_operations),
2844 #ifdef CONFIG_NUMA
2845         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2846 #endif
2847         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2848         LNK("cwd",        proc_cwd_link),
2849         LNK("root",       proc_root_link),
2850         LNK("exe",        proc_exe_link),
2851         REG("mounts",     S_IRUGO, proc_mounts_operations),
2852         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2853         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2854 #ifdef CONFIG_PROC_PAGE_MONITOR
2855         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2856         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2857         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2858 #endif
2859 #ifdef CONFIG_SECURITY
2860         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2861 #endif
2862 #ifdef CONFIG_KALLSYMS
2863         ONE("wchan",      S_IRUGO, proc_pid_wchan),
2864 #endif
2865 #ifdef CONFIG_STACKTRACE
2866         ONE("stack",      S_IRUSR, proc_pid_stack),
2867 #endif
2868 #ifdef CONFIG_SCHED_INFO
2869         ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
2870 #endif
2871 #ifdef CONFIG_LATENCYTOP
2872         REG("latency",  S_IRUGO, proc_lstats_operations),
2873 #endif
2874 #ifdef CONFIG_PROC_PID_CPUSET
2875         ONE("cpuset",     S_IRUGO, proc_cpuset_show),
2876 #endif
2877 #ifdef CONFIG_CGROUPS
2878         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
2879 #endif
2880         ONE("oom_score",  S_IRUGO, proc_oom_score),
2881         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
2882         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2883 #ifdef CONFIG_AUDITSYSCALL
2884         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2885         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2886 #endif
2887 #ifdef CONFIG_FAULT_INJECTION
2888         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2889 #endif
2890 #ifdef CONFIG_ELF_CORE
2891         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2892 #endif
2893 #ifdef CONFIG_TASK_IO_ACCOUNTING
2894         ONE("io",       S_IRUSR, proc_tgid_io_accounting),
2895 #endif
2896 #ifdef CONFIG_HARDWALL
2897         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
2898 #endif
2899 #ifdef CONFIG_USER_NS
2900         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
2901         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
2902         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
2903         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
2904 #endif
2905 #ifdef CONFIG_CHECKPOINT_RESTORE
2906         REG("timers",     S_IRUGO, proc_timers_operations),
2907 #endif
2908         REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
2909 };
2910
2911 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
2912 {
2913         return proc_pident_readdir(file, ctx,
2914                                    tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2915 }
2916
2917 static const struct file_operations proc_tgid_base_operations = {
2918         .read           = generic_read_dir,
2919         .iterate_shared = proc_tgid_base_readdir,
2920         .llseek         = generic_file_llseek,
2921 };
2922
2923 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
2924 {
2925         return proc_pident_lookup(dir, dentry,
2926                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2927 }
2928
2929 static const struct inode_operations proc_tgid_base_inode_operations = {
2930         .lookup         = proc_tgid_base_lookup,
2931         .getattr        = pid_getattr,
2932         .setattr        = proc_setattr,
2933         .permission     = proc_pid_permission,
2934 };
2935
2936 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2937 {
2938         struct dentry *dentry, *leader, *dir;
2939         char buf[PROC_NUMBUF];
2940         struct qstr name;
2941
2942         name.name = buf;
2943         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2944         /* no ->d_hash() rejects on procfs */
2945         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2946         if (dentry) {
2947                 d_invalidate(dentry);
2948                 dput(dentry);
2949         }
2950
2951         if (pid == tgid)
2952                 return;
2953
2954         name.name = buf;
2955         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2956         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2957         if (!leader)
2958                 goto out;
2959
2960         name.name = "task";
2961         name.len = strlen(name.name);
2962         dir = d_hash_and_lookup(leader, &name);
2963         if (!dir)
2964                 goto out_put_leader;
2965
2966         name.name = buf;
2967         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2968         dentry = d_hash_and_lookup(dir, &name);
2969         if (dentry) {
2970                 d_invalidate(dentry);
2971                 dput(dentry);
2972         }
2973
2974         dput(dir);
2975 out_put_leader:
2976         dput(leader);
2977 out:
2978         return;
2979 }
2980
2981 /**
2982  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2983  * @task: task that should be flushed.
2984  *
2985  * When flushing dentries from proc, one needs to flush them from global
2986  * proc (proc_mnt) and from all the namespaces' procs this task was seen
2987  * in. This call is supposed to do all of this job.
2988  *
2989  * Looks in the dcache for
2990  * /proc/@pid
2991  * /proc/@tgid/task/@pid
2992  * if either directory is present flushes it and all of it'ts children
2993  * from the dcache.
2994  *
2995  * It is safe and reasonable to cache /proc entries for a task until
2996  * that task exits.  After that they just clog up the dcache with
2997  * useless entries, possibly causing useful dcache entries to be
2998  * flushed instead.  This routine is proved to flush those useless
2999  * dcache entries at process exit time.
3000  *
3001  * NOTE: This routine is just an optimization so it does not guarantee
3002  *       that no dcache entries will exist at process exit time it
3003  *       just makes it very unlikely that any will persist.
3004  */
3005
3006 void proc_flush_task(struct task_struct *task)
3007 {
3008         int i;
3009         struct pid *pid, *tgid;
3010         struct upid *upid;
3011
3012         pid = task_pid(task);
3013         tgid = task_tgid(task);
3014
3015         for (i = 0; i <= pid->level; i++) {
3016                 upid = &pid->numbers[i];
3017                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3018                                         tgid->numbers[i].nr);
3019         }
3020 }
3021
3022 static int proc_pid_instantiate(struct inode *dir,
3023                                    struct dentry * dentry,
3024                                    struct task_struct *task, const void *ptr)
3025 {
3026         struct inode *inode;
3027
3028         inode = proc_pid_make_inode(dir->i_sb, task);
3029         if (!inode)
3030                 goto out;
3031
3032         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3033         inode->i_op = &proc_tgid_base_inode_operations;
3034         inode->i_fop = &proc_tgid_base_operations;
3035         inode->i_flags|=S_IMMUTABLE;
3036
3037         set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
3038                                                   ARRAY_SIZE(tgid_base_stuff)));
3039
3040         d_set_d_op(dentry, &pid_dentry_operations);
3041
3042         d_add(dentry, inode);
3043         /* Close the race of the process dying before we return the dentry */
3044         if (pid_revalidate(dentry, 0))
3045                 return 0;
3046 out:
3047         return -ENOENT;
3048 }
3049
3050 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3051 {
3052         int result = -ENOENT;
3053         struct task_struct *task;
3054         unsigned tgid;
3055         struct pid_namespace *ns;
3056
3057         tgid = name_to_int(&dentry->d_name);
3058         if (tgid == ~0U)
3059                 goto out;
3060
3061         ns = dentry->d_sb->s_fs_info;
3062         rcu_read_lock();
3063         task = find_task_by_pid_ns(tgid, ns);
3064         if (task)
3065                 get_task_struct(task);
3066         rcu_read_unlock();
3067         if (!task)
3068                 goto out;
3069
3070         result = proc_pid_instantiate(dir, dentry, task, NULL);
3071         put_task_struct(task);
3072 out:
3073         return ERR_PTR(result);
3074 }
3075
3076 /*
3077  * Find the first task with tgid >= tgid
3078  *
3079  */
3080 struct tgid_iter {
3081         unsigned int tgid;
3082         struct task_struct *task;
3083 };
3084 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3085 {
3086         struct pid *pid;
3087
3088         if (iter.task)
3089                 put_task_struct(iter.task);
3090         rcu_read_lock();
3091 retry:
3092         iter.task = NULL;
3093         pid = find_ge_pid(iter.tgid, ns);
3094         if (pid) {
3095                 iter.tgid = pid_nr_ns(pid, ns);
3096                 iter.task = pid_task(pid, PIDTYPE_PID);
3097                 /* What we to know is if the pid we have find is the
3098                  * pid of a thread_group_leader.  Testing for task
3099                  * being a thread_group_leader is the obvious thing
3100                  * todo but there is a window when it fails, due to
3101                  * the pid transfer logic in de_thread.
3102                  *
3103                  * So we perform the straight forward test of seeing
3104                  * if the pid we have found is the pid of a thread
3105                  * group leader, and don't worry if the task we have
3106                  * found doesn't happen to be a thread group leader.
3107                  * As we don't care in the case of readdir.
3108                  */
3109                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3110                         iter.tgid += 1;
3111                         goto retry;
3112                 }
3113                 get_task_struct(iter.task);
3114         }
3115         rcu_read_unlock();
3116         return iter;
3117 }
3118
3119 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3120
3121 /* for the /proc/ directory itself, after non-process stuff has been done */
3122 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3123 {
3124         struct tgid_iter iter;
3125         struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info;
3126         loff_t pos = ctx->pos;
3127
3128         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3129                 return 0;
3130
3131         if (pos == TGID_OFFSET - 2) {
3132                 struct inode *inode = d_inode(ns->proc_self);
3133                 if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3134                         return 0;
3135                 ctx->pos = pos = pos + 1;
3136         }
3137         if (pos == TGID_OFFSET - 1) {
3138                 struct inode *inode = d_inode(ns->proc_thread_self);
3139                 if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3140                         return 0;
3141                 ctx->pos = pos = pos + 1;
3142         }
3143         iter.tgid = pos - TGID_OFFSET;
3144         iter.task = NULL;
3145         for (iter = next_tgid(ns, iter);
3146              iter.task;
3147              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3148                 char name[PROC_NUMBUF];
3149                 int len;
3150                 if (!has_pid_permissions(ns, iter.task, 2))
3151                         continue;
3152
3153                 len = snprintf(name, sizeof(name), "%d", iter.tgid);
3154                 ctx->pos = iter.tgid + TGID_OFFSET;
3155                 if (!proc_fill_cache(file, ctx, name, len,
3156                                      proc_pid_instantiate, iter.task, NULL)) {
3157                         put_task_struct(iter.task);
3158                         return 0;
3159                 }
3160         }
3161         ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3162         return 0;
3163 }
3164
3165 /*
3166  * proc_tid_comm_permission is a special permission function exclusively
3167  * used for the node /proc/<pid>/task/<tid>/comm.
3168  * It bypasses generic permission checks in the case where a task of the same
3169  * task group attempts to access the node.
3170  * The rationale behind this is that glibc and bionic access this node for
3171  * cross thread naming (pthread_set/getname_np(!self)). However, if
3172  * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3173  * which locks out the cross thread naming implementation.
3174  * This function makes sure that the node is always accessible for members of
3175  * same thread group.
3176  */
3177 static int proc_tid_comm_permission(struct inode *inode, int mask)
3178 {
3179         bool is_same_tgroup;
3180         struct task_struct *task;
3181
3182         task = get_proc_task(inode);
3183         if (!task)
3184                 return -ESRCH;
3185         is_same_tgroup = same_thread_group(current, task);
3186         put_task_struct(task);
3187
3188         if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3189                 /* This file (/proc/<pid>/task/<tid>/comm) can always be
3190                  * read or written by the members of the corresponding
3191                  * thread group.
3192                  */
3193                 return 0;
3194         }
3195
3196         return generic_permission(inode, mask);
3197 }
3198
3199 static const struct inode_operations proc_tid_comm_inode_operations = {
3200                 .permission = proc_tid_comm_permission,
3201 };
3202
3203 /*
3204  * Tasks
3205  */
3206 static const struct pid_entry tid_base_stuff[] = {
3207         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3208         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3209         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3210 #ifdef CONFIG_NET
3211         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3212 #endif
3213         REG("environ",   S_IRUSR, proc_environ_operations),
3214         ONE("auxv",      S_IRUSR, proc_pid_auxv),
3215         ONE("status",    S_IRUGO, proc_pid_status),
3216         ONE("personality", S_IRUSR, proc_pid_personality),
3217         ONE("limits",    S_IRUGO, proc_pid_limits),
3218 #ifdef CONFIG_SCHED_DEBUG
3219         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3220 #endif
3221         NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3222                          &proc_tid_comm_inode_operations,
3223                          &proc_pid_set_comm_operations, {}),
3224 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3225         ONE("syscall",   S_IRUSR, proc_pid_syscall),
3226 #endif
3227         REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3228         ONE("stat",      S_IRUGO, proc_tid_stat),
3229         ONE("statm",     S_IRUGO, proc_pid_statm),
3230         REG("maps",      S_IRUGO, proc_tid_maps_operations),
3231 #ifdef CONFIG_PROC_CHILDREN
3232         REG("children",  S_IRUGO, proc_tid_children_operations),
3233 #endif
3234 #ifdef CONFIG_NUMA
3235         REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3236 #endif
3237         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3238         LNK("cwd",       proc_cwd_link),
3239         LNK("root",      proc_root_link),
3240         LNK("exe",       proc_exe_link),
3241         REG("mounts",    S_IRUGO, proc_mounts_operations),
3242         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3243 #ifdef CONFIG_PROC_PAGE_MONITOR
3244         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3245         REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3246         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3247 #endif
3248 #ifdef CONFIG_SECURITY
3249         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3250 #endif
3251 #ifdef CONFIG_KALLSYMS
3252         ONE("wchan",     S_IRUGO, proc_pid_wchan),
3253 #endif
3254 #ifdef CONFIG_STACKTRACE
3255         ONE("stack",      S_IRUSR, proc_pid_stack),
3256 #endif
3257 #ifdef CONFIG_SCHED_INFO
3258         ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3259 #endif
3260 #ifdef CONFIG_LATENCYTOP
3261         REG("latency",  S_IRUGO, proc_lstats_operations),
3262 #endif
3263 #ifdef CONFIG_PROC_PID_CPUSET
3264         ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3265 #endif
3266 #ifdef CONFIG_CGROUPS
3267         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3268 #endif
3269         ONE("oom_score", S_IRUGO, proc_oom_score),
3270         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3271         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3272 #ifdef CONFIG_AUDITSYSCALL
3273         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3274         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3275 #endif
3276 #ifdef CONFIG_FAULT_INJECTION
3277         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3278 #endif
3279 #ifdef CONFIG_TASK_IO_ACCOUNTING
3280         ONE("io",       S_IRUSR, proc_tid_io_accounting),
3281 #endif
3282 #ifdef CONFIG_HARDWALL
3283         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
3284 #endif
3285 #ifdef CONFIG_USER_NS
3286         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3287         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3288         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3289         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3290 #endif
3291 };
3292
3293 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3294 {
3295         return proc_pident_readdir(file, ctx,
3296                                    tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3297 }
3298
3299 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3300 {
3301         return proc_pident_lookup(dir, dentry,
3302                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3303 }
3304
3305 static const struct file_operations proc_tid_base_operations = {
3306         .read           = generic_read_dir,
3307         .iterate_shared = proc_tid_base_readdir,
3308         .llseek         = generic_file_llseek,
3309 };
3310
3311 static const struct inode_operations proc_tid_base_inode_operations = {
3312         .lookup         = proc_tid_base_lookup,
3313         .getattr        = pid_getattr,
3314         .setattr        = proc_setattr,
3315 };
3316
3317 static int proc_task_instantiate(struct inode *dir,
3318         struct dentry *dentry, struct task_struct *task, const void *ptr)
3319 {
3320         struct inode *inode;
3321         inode = proc_pid_make_inode(dir->i_sb, task);
3322
3323         if (!inode)
3324                 goto out;
3325         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3326         inode->i_op = &proc_tid_base_inode_operations;
3327         inode->i_fop = &proc_tid_base_operations;
3328         inode->i_flags|=S_IMMUTABLE;
3329
3330         set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
3331                                                   ARRAY_SIZE(tid_base_stuff)));
3332
3333         d_set_d_op(dentry, &pid_dentry_operations);
3334
3335         d_add(dentry, inode);
3336         /* Close the race of the process dying before we return the dentry */
3337         if (pid_revalidate(dentry, 0))
3338                 return 0;
3339 out:
3340         return -ENOENT;
3341 }
3342
3343 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3344 {
3345         int result = -ENOENT;
3346         struct task_struct *task;
3347         struct task_struct *leader = get_proc_task(dir);
3348         unsigned tid;
3349         struct pid_namespace *ns;
3350
3351         if (!leader)
3352                 goto out_no_task;
3353
3354         tid = name_to_int(&dentry->d_name);
3355         if (tid == ~0U)
3356                 goto out;
3357
3358         ns = dentry->d_sb->s_fs_info;
3359         rcu_read_lock();
3360         task = find_task_by_pid_ns(tid, ns);
3361         if (task)
3362                 get_task_struct(task);
3363         rcu_read_unlock();
3364         if (!task)
3365                 goto out;
3366         if (!same_thread_group(leader, task))
3367                 goto out_drop_task;
3368
3369         result = proc_task_instantiate(dir, dentry, task, NULL);
3370 out_drop_task:
3371         put_task_struct(task);
3372 out:
3373         put_task_struct(leader);
3374 out_no_task:
3375         return ERR_PTR(result);
3376 }
3377
3378 /*
3379  * Find the first tid of a thread group to return to user space.
3380  *
3381  * Usually this is just the thread group leader, but if the users
3382  * buffer was too small or there was a seek into the middle of the
3383  * directory we have more work todo.
3384  *
3385  * In the case of a short read we start with find_task_by_pid.
3386  *
3387  * In the case of a seek we start with the leader and walk nr
3388  * threads past it.
3389  */
3390 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3391                                         struct pid_namespace *ns)
3392 {
3393         struct task_struct *pos, *task;
3394         unsigned long nr = f_pos;
3395
3396         if (nr != f_pos)        /* 32bit overflow? */
3397                 return NULL;
3398
3399         rcu_read_lock();
3400         task = pid_task(pid, PIDTYPE_PID);
3401         if (!task)
3402                 goto fail;
3403
3404         /* Attempt to start with the tid of a thread */
3405         if (tid && nr) {
3406                 pos = find_task_by_pid_ns(tid, ns);
3407                 if (pos && same_thread_group(pos, task))
3408                         goto found;
3409         }
3410
3411         /* If nr exceeds the number of threads there is nothing todo */
3412         if (nr >= get_nr_threads(task))
3413                 goto fail;
3414
3415         /* If we haven't found our starting place yet start
3416          * with the leader and walk nr threads forward.
3417          */
3418         pos = task = task->group_leader;
3419         do {
3420                 if (!nr--)
3421                         goto found;
3422         } while_each_thread(task, pos);
3423 fail:
3424         pos = NULL;
3425         goto out;
3426 found:
3427         get_task_struct(pos);
3428 out:
3429         rcu_read_unlock();
3430         return pos;
3431 }
3432
3433 /*
3434  * Find the next thread in the thread list.
3435  * Return NULL if there is an error or no next thread.
3436  *
3437  * The reference to the input task_struct is released.
3438  */
3439 static struct task_struct *next_tid(struct task_struct *start)
3440 {
3441         struct task_struct *pos = NULL;
3442         rcu_read_lock();
3443         if (pid_alive(start)) {
3444                 pos = next_thread(start);
3445                 if (thread_group_leader(pos))
3446                         pos = NULL;
3447                 else
3448                         get_task_struct(pos);
3449         }
3450         rcu_read_unlock();
3451         put_task_struct(start);
3452         return pos;
3453 }
3454
3455 /* for the /proc/TGID/task/ directories */
3456 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3457 {
3458         struct inode *inode = file_inode(file);
3459         struct task_struct *task;
3460         struct pid_namespace *ns;
3461         int tid;
3462
3463         if (proc_inode_is_dead(inode))
3464                 return -ENOENT;
3465
3466         if (!dir_emit_dots(file, ctx))
3467                 return 0;
3468
3469         /* f_version caches the tgid value that the last readdir call couldn't
3470          * return. lseek aka telldir automagically resets f_version to 0.
3471          */
3472         ns = inode->i_sb->s_fs_info;
3473         tid = (int)file->f_version;
3474         file->f_version = 0;
3475         for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3476              task;
3477              task = next_tid(task), ctx->pos++) {
3478                 char name[PROC_NUMBUF];
3479                 int len;
3480                 tid = task_pid_nr_ns(task, ns);
3481                 len = snprintf(name, sizeof(name), "%d", tid);
3482                 if (!proc_fill_cache(file, ctx, name, len,
3483                                 proc_task_instantiate, task, NULL)) {
3484                         /* returning this tgid failed, save it as the first
3485                          * pid for the next readir call */
3486                         file->f_version = (u64)tid;
3487                         put_task_struct(task);
3488                         break;
3489                 }
3490         }
3491
3492         return 0;
3493 }
3494
3495 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3496 {
3497         struct inode *inode = d_inode(dentry);
3498         struct task_struct *p = get_proc_task(inode);
3499         generic_fillattr(inode, stat);
3500
3501         if (p) {
3502                 stat->nlink += get_nr_threads(p);
3503                 put_task_struct(p);
3504         }
3505
3506         return 0;
3507 }
3508
3509 static const struct inode_operations proc_task_inode_operations = {
3510         .lookup         = proc_task_lookup,
3511         .getattr        = proc_task_getattr,
3512         .setattr        = proc_setattr,
3513         .permission     = proc_pid_permission,
3514 };
3515
3516 static const struct file_operations proc_task_operations = {
3517         .read           = generic_read_dir,
3518         .iterate_shared = proc_task_readdir,
3519         .llseek         = generic_file_llseek,
3520 };