fs/proc/base.c

   1 /*
   2  *  linux/fs/proc/base.c
   3  *
   4  *  Copyright (C) 1991, 1992 Linus Torvalds
   5  *
   6  *  proc base directory handling functions
   7  *
   8  *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
   9  *  Instead of using magical inumbers to determine the kind of object
  10  *  we allocate and fill in-core inodes upon lookup. They don't even
  11  *  go into icache. We cache the reference to task_struct upon lookup too.
  12  *  Eventually it should become a filesystem in its own. We don't use the
  13  *  rest of procfs anymore.
  14  *
  15  *
  16  *  Changelog:
  17  *  17-Jan-2005
  18  *  Allan Bezerra
  19  *  Bruna Moreira <bruna.moreira@indt.org.br>
  20  *  Edjard Mota <edjard.mota@indt.org.br>
  21  *  Ilias Biris <ilias.biris@indt.org.br>
  22  *  Mauricio Lin <mauricio.lin@indt.org.br>
  23  *
  24  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  25  *
  26  *  A new process specific entry (smaps) included in /proc. It shows the
  27  *  size of rss for each memory area. The maps entry lacks information
  28  *  about physical memory size (rss) for each mapped file, i.e.,
  29  *  rss information for executables and library files.
  30  *  This additional information is useful for any tools that need to know
  31  *  about physical memory consumption for a process specific library.
  32  *
  33  *  Changelog:
  34  *  21-Feb-2005
  35  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  36  *  Pud inclusion in the page table walking.
  37  *
  38  *  ChangeLog:
  39  *  10-Mar-2005
  40  *  10LE Instituto Nokia de Tecnologia - INdT:
  41  *  A better way to walks through the page table as suggested by Hugh Dickins.
  42  *
  43  *  Simo Piiroinen <simo.piiroinen@nokia.com>:
  44  *  Smaps information related to shared, private, clean and dirty pages.
  45  *
  46  *  Paul Mundt <paul.mundt@nokia.com>:
  47  *  Overall revision about smaps.
  48  */
  49
  50 #include <asm/uaccess.h>
  51
  52 #include <linux/errno.h>
  53 #include <linux/time.h>
  54 #include <linux/proc_fs.h>
  55 #include <linux/stat.h>
  56 #include <linux/task_io_accounting_ops.h>
  57 #include <linux/init.h>
  58 #include <linux/capability.h>
  59 #include <linux/file.h>
  60 #include <linux/fdtable.h>
  61 #include <linux/string.h>
  62 #include <linux/seq_file.h>
  63 #include <linux/namei.h>
  64 #include <linux/mnt_namespace.h>
  65 #include <linux/mm.h>
  66 #include <linux/swap.h>
  67 #include <linux/rcupdate.h>
  68 #include <linux/kallsyms.h>
  69 #include <linux/stacktrace.h>
  70 #include <linux/resource.h>
  71 #include <linux/module.h>
  72 #include <linux/mount.h>
  73 #include <linux/security.h>
  74 #include <linux/ptrace.h>
  75 #include <linux/tracehook.h>
  76 #include <linux/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>] %pB\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         points = oom_badness(task, NULL, NULL, totalpages) *
 583                                         1000 / totalpages;
 584         seq_printf(m, "%lu\n", points);
 585
 586         return 0;
 587 }
 588
 589 struct limit_names {
 590         const char *name;
 591         const char *unit;
 592 };
 593
 594 static const struct limit_names lnames[RLIM_NLIMITS] = {
 595         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 596         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 597         [RLIMIT_DATA] = {"Max data size", "bytes"},
 598         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 599         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 600         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 601         [RLIMIT_NPROC] = {"Max processes", "processes"},
 602         [RLIMIT_NOFILE] = {"Max open files", "files"},
 603         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 604         [RLIMIT_AS] = {"Max address space", "bytes"},
 605         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 606         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 607         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 608         [RLIMIT_NICE] = {"Max nice priority", NULL},
 609         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 610         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 611 };
 612
 613 /* Display limits for a process */
 614 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 615                            struct pid *pid, struct task_struct *task)
 616 {
 617         unsigned int i;
 618         unsigned long flags;
 619
 620         struct rlimit rlim[RLIM_NLIMITS];
 621
 622         if (!lock_task_sighand(task, &flags))
 623                 return 0;
 624         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 625         unlock_task_sighand(task, &flags);
 626
 627         /*
 628          * print the file header
 629          */
 630        seq_printf(m, "%-25s %-20s %-20s %-10s\n",
 631                   "Limit", "Soft Limit", "Hard Limit", "Units");
 632
 633         for (i = 0; i < RLIM_NLIMITS; i++) {
 634                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 635                         seq_printf(m, "%-25s %-20s ",
 636                                    lnames[i].name, "unlimited");
 637                 else
 638                         seq_printf(m, "%-25s %-20lu ",
 639                                    lnames[i].name, rlim[i].rlim_cur);
 640
 641                 if (rlim[i].rlim_max == RLIM_INFINITY)
 642                         seq_printf(m, "%-20s ", "unlimited");
 643                 else
 644                         seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 645
 646                 if (lnames[i].unit)
 647                         seq_printf(m, "%-10s\n", lnames[i].unit);
 648                 else
 649                         seq_putc(m, '\n');
 650         }
 651
 652         return 0;
 653 }
 654
 655 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 656 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 657                             struct pid *pid, struct task_struct *task)
 658 {
 659         long nr;
 660         unsigned long args[6], sp, pc;
 661         int res;
 662
 663         res = lock_trace(task);
 664         if (res)
 665                 return res;
 666
 667         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 668                 seq_puts(m, "running\n");
 669         else if (nr < 0)
 670                 seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 671         else
 672                 seq_printf(m,
 673                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 674                        nr,
 675                        args[0], args[1], args[2], args[3], args[4], args[5],
 676                        sp, pc);
 677         unlock_trace(task);
 678
 679         return 0;
 680 }
 681 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 682
 683 /************************************************************************/
 684 /*                       Here the fs part begins                        */
 685 /************************************************************************/
 686
 687 /* permission checks */
 688 static int proc_fd_access_allowed(struct inode *inode)
 689 {
 690         struct task_struct *task;
 691         int allowed = 0;
 692         /* Allow access to a task's file descriptors if it is us or we
 693          * may use ptrace attach to the process and find out that
 694          * information.
 695          */
 696         task = get_proc_task(inode);
 697         if (task) {
 698                 allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 699                 put_task_struct(task);
 700         }
 701         return allowed;
 702 }
 703
 704 int proc_setattr(struct dentry *dentry, struct iattr *attr)
 705 {
 706         int error;
 707         struct inode *inode = d_inode(dentry);
 708
 709         if (attr->ia_valid & ATTR_MODE)
 710                 return -EPERM;
 711
 712         error = inode_change_ok(inode, attr);
 713         if (error)
 714                 return error;
 715
 716         setattr_copy(inode, attr);
 717         mark_inode_dirty(inode);
 718         return 0;
 719 }
 720
 721 /*
 722  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 723  * or euid/egid (for hide_pid_min=2)?
 724  */
 725 static bool has_pid_permissions(struct pid_namespace *pid,
 726                                  struct task_struct *task,
 727                                  int hide_pid_min)
 728 {
 729         if (pid->hide_pid < hide_pid_min)
 730                 return true;
 731         if (in_group_p(pid->pid_gid))
 732                 return true;
 733         return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 734 }
 735
 736
 737 static int proc_pid_permission(struct inode *inode, int mask)
 738 {
 739         struct pid_namespace *pid = inode->i_sb->s_fs_info;
 740         struct task_struct *task;
 741         bool has_perms;
 742
 743         task = get_proc_task(inode);
 744         if (!task)
 745                 return -ESRCH;
 746         has_perms = has_pid_permissions(pid, task, 1);
 747         put_task_struct(task);
 748
 749         if (!has_perms) {
 750                 if (pid->hide_pid == 2) {
 751                         /*
 752                          * Let's make getdents(), stat(), and open()
 753                          * consistent with each other.  If a process
 754                          * may not stat() a file, it shouldn't be seen
 755                          * in procfs at all.
 756                          */
 757                         return -ENOENT;
 758                 }
 759
 760                 return -EPERM;
 761         }
 762         return generic_permission(inode, mask);
 763 }
 764
 765
 766
 767 static const struct inode_operations proc_def_inode_operations = {
 768         .setattr        = proc_setattr,
 769 };
 770
 771 static int proc_single_show(struct seq_file *m, void *v)
 772 {
 773         struct inode *inode = m->private;
 774         struct pid_namespace *ns;
 775         struct pid *pid;
 776         struct task_struct *task;
 777         int ret;
 778
 779         ns = inode->i_sb->s_fs_info;
 780         pid = proc_pid(inode);
 781         task = get_pid_task(pid, PIDTYPE_PID);
 782         if (!task)
 783                 return -ESRCH;
 784
 785         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 786
 787         put_task_struct(task);
 788         return ret;
 789 }
 790
 791 static int proc_single_open(struct inode *inode, struct file *filp)
 792 {
 793         return single_open(filp, proc_single_show, inode);
 794 }
 795
 796 static const struct file_operations proc_single_file_operations = {
 797         .open           = proc_single_open,
 798         .read           = seq_read,
 799         .llseek         = seq_lseek,
 800         .release        = single_release,
 801 };
 802
 803
 804 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 805 {
 806         struct task_struct *task = get_proc_task(inode);
 807         struct mm_struct *mm = ERR_PTR(-ESRCH);
 808
 809         if (task) {
 810                 mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 811                 put_task_struct(task);
 812
 813                 if (!IS_ERR_OR_NULL(mm)) {
 814                         /* ensure this mm_struct can't be freed */
 815                         atomic_inc(&mm->mm_count);
 816                         /* but do not pin its memory */
 817                         mmput(mm);
 818                 }
 819         }
 820
 821         return mm;
 822 }
 823
 824 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 825 {
 826         struct mm_struct *mm = proc_mem_open(inode, mode);
 827
 828         if (IS_ERR(mm))
 829                 return PTR_ERR(mm);
 830
 831         file->private_data = mm;
 832         return 0;
 833 }
 834
 835 static int mem_open(struct inode *inode, struct file *file)
 836 {
 837         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 838
 839         /* OK to pass negative loff_t, we can catch out-of-range */
 840         file->f_mode |= FMODE_UNSIGNED_OFFSET;
 841
 842         return ret;
 843 }
 844
 845 static ssize_t mem_rw(struct file *file, char __user *buf,
 846                         size_t count, loff_t *ppos, int write)
 847 {
 848         struct mm_struct *mm = file->private_data;
 849         unsigned long addr = *ppos;
 850         ssize_t copied;
 851         char *page;
 852
 853         if (!mm)
 854                 return 0;
 855
 856         page = (char *)__get_free_page(GFP_TEMPORARY);
 857         if (!page)
 858                 return -ENOMEM;
 859
 860         copied = 0;
 861         if (!atomic_inc_not_zero(&mm->mm_users))
 862                 goto free;
 863
 864         while (count > 0) {
 865                 int this_len = min_t(int, count, PAGE_SIZE);
 866
 867                 if (write && copy_from_user(page, buf, this_len)) {
 868                         copied = -EFAULT;
 869                         break;
 870                 }
 871
 872                 this_len = access_remote_vm(mm, addr, page, this_len, write);
 873                 if (!this_len) {
 874                         if (!copied)
 875                                 copied = -EIO;
 876                         break;
 877                 }
 878
 879                 if (!write && copy_to_user(buf, page, this_len)) {
 880                         copied = -EFAULT;
 881                         break;
 882                 }
 883
 884                 buf += this_len;
 885                 addr += this_len;
 886                 copied += this_len;
 887                 count -= this_len;
 888         }
 889         *ppos = addr;
 890
 891         mmput(mm);
 892 free:
 893         free_page((unsigned long) page);
 894         return copied;
 895 }
 896
 897 static ssize_t mem_read(struct file *file, char __user *buf,
 898                         size_t count, loff_t *ppos)
 899 {
 900         return mem_rw(file, buf, count, ppos, 0);
 901 }
 902
 903 static ssize_t mem_write(struct file *file, const char __user *buf,
 904                          size_t count, loff_t *ppos)
 905 {
 906         return mem_rw(file, (char __user*)buf, count, ppos, 1);
 907 }
 908
 909 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 910 {
 911         switch (orig) {
 912         case 0:
 913                 file->f_pos = offset;
 914                 break;
 915         case 1:
 916                 file->f_pos += offset;
 917                 break;
 918         default:
 919                 return -EINVAL;
 920         }
 921         force_successful_syscall_return();
 922         return file->f_pos;
 923 }
 924
 925 static int mem_release(struct inode *inode, struct file *file)
 926 {
 927         struct mm_struct *mm = file->private_data;
 928         if (mm)
 929                 mmdrop(mm);
 930         return 0;
 931 }
 932
 933 static const struct file_operations proc_mem_operations = {
 934         .llseek         = mem_lseek,
 935         .read           = mem_read,
 936         .write          = mem_write,
 937         .open           = mem_open,
 938         .release        = mem_release,
 939 };
 940
 941 static int environ_open(struct inode *inode, struct file *file)
 942 {
 943         return __mem_open(inode, file, PTRACE_MODE_READ);
 944 }
 945
 946 static ssize_t environ_read(struct file *file, char __user *buf,
 947                         size_t count, loff_t *ppos)
 948 {
 949         char *page;
 950         unsigned long src = *ppos;
 951         int ret = 0;
 952         struct mm_struct *mm = file->private_data;
 953         unsigned long env_start, env_end;
 954
 955         /* Ensure the process spawned far enough to have an environment. */
 956         if (!mm || !mm->env_end)
 957                 return 0;
 958
 959         page = (char *)__get_free_page(GFP_TEMPORARY);
 960         if (!page)
 961                 return -ENOMEM;
 962
 963         ret = 0;
 964         if (!atomic_inc_not_zero(&mm->mm_users))
 965                 goto free;
 966
 967         down_read(&mm->mmap_sem);
 968         env_start = mm->env_start;
 969         env_end = mm->env_end;
 970         up_read(&mm->mmap_sem);
 971
 972         while (count > 0) {
 973                 size_t this_len, max_len;
 974                 int retval;
 975
 976                 if (src >= (env_end - env_start))
 977                         break;
 978
 979                 this_len = env_end - (env_start + src);
 980
 981                 max_len = min_t(size_t, PAGE_SIZE, count);
 982                 this_len = min(max_len, this_len);
 983
 984                 retval = access_remote_vm(mm, (env_start + src),
 985                         page, this_len, 0);
 986
 987                 if (retval <= 0) {
 988                         ret = retval;
 989                         break;
 990                 }
 991
 992                 if (copy_to_user(buf, page, retval)) {
 993                         ret = -EFAULT;
 994                         break;
 995                 }
 996
 997                 ret += retval;
 998                 src += retval;
 999                 buf += retval;
1000                 count -= retval;
1001         }
1002         *ppos = src;
1003         mmput(mm);
1004
1005 free:
1006         free_page((unsigned long) page);
1007         return ret;
1008 }
1009
1010 static const struct file_operations proc_environ_operations = {
1011         .open           = environ_open,
1012         .read           = environ_read,
1013         .llseek         = generic_file_llseek,
1014         .release        = mem_release,
1015 };
1016
1017 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1018                             loff_t *ppos)
1019 {
1020         struct task_struct *task = get_proc_task(file_inode(file));
1021         char buffer[PROC_NUMBUF];
1022         int oom_adj = OOM_ADJUST_MIN;
1023         size_t len;
1024
1025         if (!task)
1026                 return -ESRCH;
1027         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1028                 oom_adj = OOM_ADJUST_MAX;
1029         else
1030                 oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1031                           OOM_SCORE_ADJ_MAX;
1032         put_task_struct(task);
1033         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1034         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1035 }
1036
1037 static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1038 {
1039         static DEFINE_MUTEX(oom_adj_mutex);
1040         struct mm_struct *mm = NULL;
1041         struct task_struct *task;
1042         int err = 0;
1043
1044         task = get_proc_task(file_inode(file));
1045         if (!task)
1046                 return -ESRCH;
1047
1048         mutex_lock(&oom_adj_mutex);
1049         if (legacy) {
1050                 if (oom_adj < task->signal->oom_score_adj &&
1051                                 !capable(CAP_SYS_RESOURCE)) {
1052                         err = -EACCES;
1053                         goto err_unlock;
1054                 }
1055                 /*
1056                  * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1057                  * /proc/pid/oom_score_adj instead.
1058                  */
1059                 pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1060                           current->comm, task_pid_nr(current), task_pid_nr(task),
1061                           task_pid_nr(task));
1062         } else {
1063                 if ((short)oom_adj < task->signal->oom_score_adj_min &&
1064                                 !capable(CAP_SYS_RESOURCE)) {
1065                         err = -EACCES;
1066                         goto err_unlock;
1067                 }
1068         }
1069
1070         /*
1071          * Make sure we will check other processes sharing the mm if this is
1072          * not vfrok which wants its own oom_score_adj.
1073          * pin the mm so it doesn't go away and get reused after task_unlock
1074          */
1075         if (!task->vfork_done) {
1076                 struct task_struct *p = find_lock_task_mm(task);
1077
1078                 if (p) {
1079                         if (atomic_read(&p->mm->mm_users) > 1) {
1080                                 mm = p->mm;
1081                                 atomic_inc(&mm->mm_count);
1082                         }
1083                         task_unlock(p);
1084                 }
1085         }
1086
1087         task->signal->oom_score_adj = oom_adj;
1088         if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1089                 task->signal->oom_score_adj_min = (short)oom_adj;
1090         trace_oom_score_adj_update(task);
1091
1092         if (mm) {
1093                 struct task_struct *p;
1094
1095                 rcu_read_lock();
1096                 for_each_process(p) {
1097                         if (same_thread_group(task, p))
1098                                 continue;
1099
1100                         /* do not touch kernel threads or the global init */
1101                         if (p->flags & PF_KTHREAD || is_global_init(p))
1102                                 continue;
1103
1104                         task_lock(p);
1105                         if (!p->vfork_done && process_shares_mm(p, mm)) {
1106                                 pr_info("updating oom_score_adj for %d (%s) from %d to %d because it shares mm with %d (%s). Report if this is unexpected.\n",
1107                                                 task_pid_nr(p), p->comm,
1108                                                 p->signal->oom_score_adj, oom_adj,
1109                                                 task_pid_nr(task), task->comm);
1110                                 p->signal->oom_score_adj = oom_adj;
1111                                 if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1112                                         p->signal->oom_score_adj_min = (short)oom_adj;
1113                         }
1114                         task_unlock(p);
1115                 }
1116                 rcu_read_unlock();
1117                 mmdrop(mm);
1118         }
1119 err_unlock:
1120         mutex_unlock(&oom_adj_mutex);
1121         put_task_struct(task);
1122         return err;
1123 }
1124
1125 /*
1126  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1127  * kernels.  The effective policy is defined by oom_score_adj, which has a
1128  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1129  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1130  * Processes that become oom disabled via oom_adj will still be oom disabled
1131  * with this implementation.
1132  *
1133  * oom_adj cannot be removed since existing userspace binaries use it.
1134  */
1135 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1136                              size_t count, loff_t *ppos)
1137 {
1138         char buffer[PROC_NUMBUF];
1139         int oom_adj;
1140         int err;
1141
1142         memset(buffer, 0, sizeof(buffer));
1143         if (count > sizeof(buffer) - 1)
1144                 count = sizeof(buffer) - 1;
1145         if (copy_from_user(buffer, buf, count)) {
1146                 err = -EFAULT;
1147                 goto out;
1148         }
1149
1150         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1151         if (err)
1152                 goto out;
1153         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1154              oom_adj != OOM_DISABLE) {
1155                 err = -EINVAL;
1156                 goto out;
1157         }
1158
1159         /*
1160          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1161          * value is always attainable.
1162          */
1163         if (oom_adj == OOM_ADJUST_MAX)
1164                 oom_adj = OOM_SCORE_ADJ_MAX;
1165         else
1166                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1167
1168         err = __set_oom_adj(file, oom_adj, true);
1169 out:
1170         return err < 0 ? err : count;
1171 }
1172
1173 static const struct file_operations proc_oom_adj_operations = {
1174         .read           = oom_adj_read,
1175         .write          = oom_adj_write,
1176         .llseek         = generic_file_llseek,
1177 };
1178
1179 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1180                                         size_t count, loff_t *ppos)
1181 {
1182         struct task_struct *task = get_proc_task(file_inode(file));
1183         char buffer[PROC_NUMBUF];
1184         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1185         size_t len;
1186
1187         if (!task)
1188                 return -ESRCH;
1189         oom_score_adj = task->signal->oom_score_adj;
1190         put_task_struct(task);
1191         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1192         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1193 }
1194
1195 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1196                                         size_t count, loff_t *ppos)
1197 {
1198         char buffer[PROC_NUMBUF];
1199         int oom_score_adj;
1200         int err;
1201
1202         memset(buffer, 0, sizeof(buffer));
1203         if (count > sizeof(buffer) - 1)
1204                 count = sizeof(buffer) - 1;
1205         if (copy_from_user(buffer, buf, count)) {
1206                 err = -EFAULT;
1207                 goto out;
1208         }
1209
1210         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1211         if (err)
1212                 goto out;
1213         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1214                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1215                 err = -EINVAL;
1216                 goto out;
1217         }
1218
1219         err = __set_oom_adj(file, oom_score_adj, false);
1220 out:
1221         return err < 0 ? err : count;
1222 }
1223
1224 static const struct file_operations proc_oom_score_adj_operations = {
1225         .read           = oom_score_adj_read,
1226         .write          = oom_score_adj_write,
1227         .llseek         = default_llseek,
1228 };
1229
1230 #ifdef CONFIG_AUDITSYSCALL
1231 #define TMPBUFLEN 21
1232 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1233                                   size_t count, loff_t *ppos)
1234 {
1235         struct inode * inode = file_inode(file);
1236         struct task_struct *task = get_proc_task(inode);
1237         ssize_t length;
1238         char tmpbuf[TMPBUFLEN];
1239
1240         if (!task)
1241                 return -ESRCH;
1242         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1243                            from_kuid(file->f_cred->user_ns,
1244                                      audit_get_loginuid(task)));
1245         put_task_struct(task);
1246         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1247 }
1248
1249 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1250                                    size_t count, loff_t *ppos)
1251 {
1252         struct inode * inode = file_inode(file);
1253         uid_t loginuid;
1254         kuid_t kloginuid;
1255         int rv;
1256
1257         rcu_read_lock();
1258         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1259                 rcu_read_unlock();
1260                 return -EPERM;
1261         }
1262         rcu_read_unlock();
1263
1264         if (*ppos != 0) {
1265                 /* No partial writes. */
1266                 return -EINVAL;
1267         }
1268
1269         rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1270         if (rv < 0)
1271                 return rv;
1272
1273         /* is userspace tring to explicitly UNSET the loginuid? */
1274         if (loginuid == AUDIT_UID_UNSET) {
1275                 kloginuid = INVALID_UID;
1276         } else {
1277                 kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1278                 if (!uid_valid(kloginuid))
1279                         return -EINVAL;
1280         }
1281
1282         rv = audit_set_loginuid(kloginuid);
1283         if (rv < 0)
1284                 return rv;
1285         return count;
1286 }
1287
1288 static const struct file_operations proc_loginuid_operations = {
1289         .read           = proc_loginuid_read,
1290         .write          = proc_loginuid_write,
1291         .llseek         = generic_file_llseek,
1292 };
1293
1294 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1295                                   size_t count, loff_t *ppos)
1296 {
1297         struct inode * inode = file_inode(file);
1298         struct task_struct *task = get_proc_task(inode);
1299         ssize_t length;
1300         char tmpbuf[TMPBUFLEN];
1301
1302         if (!task)
1303                 return -ESRCH;
1304         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1305                                 audit_get_sessionid(task));
1306         put_task_struct(task);
1307         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1308 }
1309
1310 static const struct file_operations proc_sessionid_operations = {
1311         .read           = proc_sessionid_read,
1312         .llseek         = generic_file_llseek,
1313 };
1314 #endif
1315
1316 #ifdef CONFIG_FAULT_INJECTION
1317 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1318                                       size_t count, loff_t *ppos)
1319 {
1320         struct task_struct *task = get_proc_task(file_inode(file));
1321         char buffer[PROC_NUMBUF];
1322         size_t len;
1323         int make_it_fail;
1324
1325         if (!task)
1326                 return -ESRCH;
1327         make_it_fail = task->make_it_fail;
1328         put_task_struct(task);
1329
1330         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1331
1332         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1333 }
1334
1335 static ssize_t proc_fault_inject_write(struct file * file,
1336                         const char __user * buf, size_t count, loff_t *ppos)
1337 {
1338         struct task_struct *task;
1339         char buffer[PROC_NUMBUF];
1340         int make_it_fail;
1341         int rv;
1342
1343         if (!capable(CAP_SYS_RESOURCE))
1344                 return -EPERM;
1345         memset(buffer, 0, sizeof(buffer));
1346         if (count > sizeof(buffer) - 1)
1347                 count = sizeof(buffer) - 1;
1348         if (copy_from_user(buffer, buf, count))
1349                 return -EFAULT;
1350         rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1351         if (rv < 0)
1352                 return rv;
1353         if (make_it_fail < 0 || make_it_fail > 1)
1354                 return -EINVAL;
1355
1356         task = get_proc_task(file_inode(file));
1357         if (!task)
1358                 return -ESRCH;
1359         task->make_it_fail = make_it_fail;
1360         put_task_struct(task);
1361
1362         return count;
1363 }
1364
1365 static const struct file_operations proc_fault_inject_operations = {
1366         .read           = proc_fault_inject_read,
1367         .write          = proc_fault_inject_write,
1368         .llseek         = generic_file_llseek,
1369 };
1370 #endif
1371
1372
1373 #ifdef CONFIG_SCHED_DEBUG
1374 /*
1375  * Print out various scheduling related per-task fields:
1376  */
1377 static int sched_show(struct seq_file *m, void *v)
1378 {
1379         struct inode *inode = m->private;
1380         struct task_struct *p;
1381
1382         p = get_proc_task(inode);
1383         if (!p)
1384                 return -ESRCH;
1385         proc_sched_show_task(p, m);
1386
1387         put_task_struct(p);
1388
1389         return 0;
1390 }
1391
1392 static ssize_t
1393 sched_write(struct file *file, const char __user *buf,
1394             size_t count, loff_t *offset)
1395 {
1396         struct inode *inode = file_inode(file);
1397         struct task_struct *p;
1398
1399         p = get_proc_task(inode);
1400         if (!p)
1401                 return -ESRCH;
1402         proc_sched_set_task(p);
1403
1404         put_task_struct(p);
1405
1406         return count;
1407 }
1408
1409 static int sched_open(struct inode *inode, struct file *filp)
1410 {
1411         return single_open(filp, sched_show, inode);
1412 }
1413
1414 static const struct file_operations proc_pid_sched_operations = {
1415         .open           = sched_open,
1416         .read           = seq_read,
1417         .write          = sched_write,
1418         .llseek         = seq_lseek,
1419         .release        = single_release,
1420 };
1421
1422 #endif
1423
1424 #ifdef CONFIG_SCHED_AUTOGROUP
1425 /*
1426  * Print out autogroup related information:
1427  */
1428 static int sched_autogroup_show(struct seq_file *m, void *v)
1429 {
1430         struct inode *inode = m->private;
1431         struct task_struct *p;
1432
1433         p = get_proc_task(inode);
1434         if (!p)
1435                 return -ESRCH;
1436         proc_sched_autogroup_show_task(p, m);
1437
1438         put_task_struct(p);
1439
1440         return 0;
1441 }
1442
1443 static ssize_t
1444 sched_autogroup_write(struct file *file, const char __user *buf,
1445             size_t count, loff_t *offset)
1446 {
1447         struct inode *inode = file_inode(file);
1448         struct task_struct *p;
1449         char buffer[PROC_NUMBUF];
1450         int nice;
1451         int err;
1452
1453         memset(buffer, 0, sizeof(buffer));
1454         if (count > sizeof(buffer) - 1)
1455                 count = sizeof(buffer) - 1;
1456         if (copy_from_user(buffer, buf, count))
1457                 return -EFAULT;
1458
1459         err = kstrtoint(strstrip(buffer), 0, &nice);
1460         if (err < 0)
1461                 return err;
1462
1463         p = get_proc_task(inode);
1464         if (!p)
1465                 return -ESRCH;
1466
1467         err = proc_sched_autogroup_set_nice(p, nice);
1468         if (err)
1469                 count = err;
1470
1471         put_task_struct(p);
1472
1473         return count;
1474 }
1475
1476 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1477 {
1478         int ret;
1479
1480         ret = single_open(filp, sched_autogroup_show, NULL);
1481         if (!ret) {
1482                 struct seq_file *m = filp->private_data;
1483
1484                 m->private = inode;
1485         }
1486         return ret;
1487 }
1488
1489 static const struct file_operations proc_pid_sched_autogroup_operations = {
1490         .open           = sched_autogroup_open,
1491         .read           = seq_read,
1492         .write          = sched_autogroup_write,
1493         .llseek         = seq_lseek,
1494         .release        = single_release,
1495 };
1496
1497 #endif /* CONFIG_SCHED_AUTOGROUP */
1498
1499 static ssize_t comm_write(struct file *file, const char __user *buf,
1500                                 size_t count, loff_t *offset)
1501 {
1502         struct inode *inode = file_inode(file);
1503         struct task_struct *p;
1504         char buffer[TASK_COMM_LEN];
1505         const size_t maxlen = sizeof(buffer) - 1;
1506
1507         memset(buffer, 0, sizeof(buffer));
1508         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1509                 return -EFAULT;
1510
1511         p = get_proc_task(inode);
1512         if (!p)
1513                 return -ESRCH;
1514
1515         if (same_thread_group(current, p))
1516                 set_task_comm(p, buffer);
1517         else
1518                 count = -EINVAL;
1519
1520         put_task_struct(p);
1521
1522         return count;
1523 }
1524
1525 static int comm_show(struct seq_file *m, void *v)
1526 {
1527         struct inode *inode = m->private;
1528         struct task_struct *p;
1529
1530         p = get_proc_task(inode);
1531         if (!p)
1532                 return -ESRCH;
1533
1534         task_lock(p);
1535         seq_printf(m, "%s\n", p->comm);
1536         task_unlock(p);
1537
1538         put_task_struct(p);
1539
1540         return 0;
1541 }
1542
1543 static int comm_open(struct inode *inode, struct file *filp)
1544 {
1545         return single_open(filp, comm_show, inode);
1546 }
1547
1548 static const struct file_operations proc_pid_set_comm_operations = {
1549         .open           = comm_open,
1550         .read           = seq_read,
1551         .write          = comm_write,
1552         .llseek         = seq_lseek,
1553         .release        = single_release,
1554 };
1555
1556 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1557 {
1558         struct task_struct *task;
1559         struct file *exe_file;
1560
1561         task = get_proc_task(d_inode(dentry));
1562         if (!task)
1563                 return -ENOENT;
1564         exe_file = get_task_exe_file(task);
1565         put_task_struct(task);
1566         if (exe_file) {
1567                 *exe_path = exe_file->f_path;
1568                 path_get(&exe_file->f_path);
1569                 fput(exe_file);
1570                 return 0;
1571         } else
1572                 return -ENOENT;
1573 }
1574
1575 static const char *proc_pid_get_link(struct dentry *dentry,
1576                                      struct inode *inode,
1577                                      struct delayed_call *done)
1578 {
1579         struct path path;
1580         int error = -EACCES;
1581
1582         if (!dentry)
1583                 return ERR_PTR(-ECHILD);
1584
1585         /* Are we allowed to snoop on the tasks file descriptors? */
1586         if (!proc_fd_access_allowed(inode))
1587                 goto out;
1588
1589         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1590         if (error)
1591                 goto out;
1592
1593         nd_jump_link(&path);
1594         return NULL;
1595 out:
1596         return ERR_PTR(error);
1597 }
1598
1599 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1600 {
1601         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1602         char *pathname;
1603         int len;
1604
1605         if (!tmp)
1606                 return -ENOMEM;
1607
1608         pathname = d_path(path, tmp, PAGE_SIZE);
1609         len = PTR_ERR(pathname);
1610         if (IS_ERR(pathname))
1611                 goto out;
1612         len = tmp + PAGE_SIZE - 1 - pathname;
1613
1614         if (len > buflen)
1615                 len = buflen;
1616         if (copy_to_user(buffer, pathname, len))
1617                 len = -EFAULT;
1618  out:
1619         free_page((unsigned long)tmp);
1620         return len;
1621 }
1622
1623 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1624 {
1625         int error = -EACCES;
1626         struct inode *inode = d_inode(dentry);
1627         struct path path;
1628
1629         /* Are we allowed to snoop on the tasks file descriptors? */
1630         if (!proc_fd_access_allowed(inode))
1631                 goto out;
1632
1633         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1634         if (error)
1635                 goto out;
1636
1637         error = do_proc_readlink(&path, buffer, buflen);
1638         path_put(&path);
1639 out:
1640         return error;
1641 }
1642
1643 const struct inode_operations proc_pid_link_inode_operations = {
1644         .readlink       = proc_pid_readlink,
1645         .get_link       = proc_pid_get_link,
1646         .setattr        = proc_setattr,
1647 };
1648
1649
1650 /* building an inode */
1651
1652 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1653 {
1654         struct inode * inode;
1655         struct proc_inode *ei;
1656         const struct cred *cred;
1657
1658         /* We need a new inode */
1659
1660         inode = new_inode(sb);
1661         if (!inode)
1662                 goto out;
1663
1664         /* Common stuff */
1665         ei = PROC_I(inode);
1666         inode->i_ino = get_next_ino();
1667         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1668         inode->i_op = &proc_def_inode_operations;
1669
1670         /*
1671          * grab the reference to task.
1672          */
1673         ei->pid = get_task_pid(task, PIDTYPE_PID);
1674         if (!ei->pid)
1675                 goto out_unlock;
1676
1677         if (task_dumpable(task)) {
1678                 rcu_read_lock();
1679                 cred = __task_cred(task);
1680                 inode->i_uid = cred->euid;
1681                 inode->i_gid = cred->egid;
1682                 rcu_read_unlock();
1683         }
1684         security_task_to_inode(task, inode);
1685
1686 out:
1687         return inode;
1688
1689 out_unlock:
1690         iput(inode);
1691         return NULL;
1692 }
1693
1694 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1695 {
1696         struct inode *inode = d_inode(dentry);
1697         struct task_struct *task;
1698         const struct cred *cred;
1699         struct pid_namespace *pid = dentry->d_sb->s_fs_info;
1700
1701         generic_fillattr(inode, stat);
1702
1703         rcu_read_lock();
1704         stat->uid = GLOBAL_ROOT_UID;
1705         stat->gid = GLOBAL_ROOT_GID;
1706         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1707         if (task) {
1708                 if (!has_pid_permissions(pid, task, 2)) {
1709                         rcu_read_unlock();
1710                         /*
1711                          * This doesn't prevent learning whether PID exists,
1712                          * it only makes getattr() consistent with readdir().
1713                          */
1714                         return -ENOENT;
1715                 }
1716                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1717                     task_dumpable(task)) {
1718                         cred = __task_cred(task);
1719                         stat->uid = cred->euid;
1720                         stat->gid = cred->egid;
1721                 }
1722         }
1723         rcu_read_unlock();
1724         return 0;
1725 }
1726
1727 /* dentry stuff */
1728
1729 /*
1730  *      Exceptional case: normally we are not allowed to unhash a busy
1731  * directory. In this case, however, we can do it - no aliasing problems
1732  * due to the way we treat inodes.
1733  *
1734  * Rewrite the inode's ownerships here because the owning task may have
1735  * performed a setuid(), etc.
1736  *
1737  * Before the /proc/pid/status file was created the only way to read
1738  * the effective uid of a /process was to stat /proc/pid.  Reading
1739  * /proc/pid/status is slow enough that procps and other packages
1740  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1741  * made this apply to all per process world readable and executable
1742  * directories.
1743  */
1744 int pid_revalidate(struct dentry *dentry, unsigned int flags)
1745 {
1746         struct inode *inode;
1747         struct task_struct *task;
1748         const struct cred *cred;
1749
1750         if (flags & LOOKUP_RCU)
1751                 return -ECHILD;
1752
1753         inode = d_inode(dentry);
1754         task = get_proc_task(inode);
1755
1756         if (task) {
1757                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1758                     task_dumpable(task)) {
1759                         rcu_read_lock();
1760                         cred = __task_cred(task);
1761                         inode->i_uid = cred->euid;
1762                         inode->i_gid = cred->egid;
1763                         rcu_read_unlock();
1764                 } else {
1765                         inode->i_uid = GLOBAL_ROOT_UID;
1766                         inode->i_gid = GLOBAL_ROOT_GID;
1767                 }
1768                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1769                 security_task_to_inode(task, inode);
1770                 put_task_struct(task);
1771                 return 1;
1772         }
1773         return 0;
1774 }
1775
1776 static inline bool proc_inode_is_dead(struct inode *inode)
1777 {
1778         return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1779 }
1780
1781 int pid_delete_dentry(const struct dentry *dentry)
1782 {
1783         /* Is the task we represent dead?
1784          * If so, then don't put the dentry on the lru list,
1785          * kill it immediately.
1786          */
1787         return proc_inode_is_dead(d_inode(dentry));
1788 }
1789
1790 const struct dentry_operations pid_dentry_operations =
1791 {
1792         .d_revalidate   = pid_revalidate,
1793         .d_delete       = pid_delete_dentry,
1794 };
1795
1796 /* Lookups */
1797
1798 /*
1799  * Fill a directory entry.
1800  *
1801  * If possible create the dcache entry and derive our inode number and
1802  * file type from dcache entry.
1803  *
1804  * Since all of the proc inode numbers are dynamically generated, the inode
1805  * numbers do not exist until the inode is cache.  This means creating the
1806  * the dcache entry in readdir is necessary to keep the inode numbers
1807  * reported by readdir in sync with the inode numbers reported
1808  * by stat.
1809  */
1810 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1811         const char *name, int len,
1812         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1813 {
1814         struct dentry *child, *dir = file->f_path.dentry;
1815         struct qstr qname = QSTR_INIT(name, len);
1816         struct inode *inode;
1817         unsigned type;
1818         ino_t ino;
1819
1820         child = d_hash_and_lookup(dir, &qname);
1821         if (!child) {
1822                 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1823                 child = d_alloc_parallel(dir, &qname, &wq);
1824                 if (IS_ERR(child))
1825                         goto end_instantiate;
1826                 if (d_in_lookup(child)) {
1827                         int err = instantiate(d_inode(dir), child, task, ptr);
1828                         d_lookup_done(child);
1829                         if (err < 0) {
1830                                 dput(child);
1831                                 goto end_instantiate;
1832                         }
1833                 }
1834         }
1835         inode = d_inode(child);
1836         ino = inode->i_ino;
1837         type = inode->i_mode >> 12;
1838         dput(child);
1839         return dir_emit(ctx, name, len, ino, type);
1840
1841 end_instantiate:
1842         return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
1843 }
1844
1845 /*
1846  * dname_to_vma_addr - maps a dentry name into two unsigned longs
1847  * which represent vma start and end addresses.
1848  */
1849 static int dname_to_vma_addr(struct dentry *dentry,
1850                              unsigned long *start, unsigned long *end)
1851 {
1852         if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
1853                 return -EINVAL;
1854
1855         return 0;
1856 }
1857
1858 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1859 {
1860         unsigned long vm_start, vm_end;
1861         bool exact_vma_exists = false;
1862         struct mm_struct *mm = NULL;
1863         struct task_struct *task;
1864         const struct cred *cred;
1865         struct inode *inode;
1866         int status = 0;
1867
1868         if (flags & LOOKUP_RCU)
1869                 return -ECHILD;
1870
1871         inode = d_inode(dentry);
1872         task = get_proc_task(inode);
1873         if (!task)
1874                 goto out_notask;
1875
1876         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1877         if (IS_ERR_OR_NULL(mm))
1878                 goto out;
1879
1880         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1881                 down_read(&mm->mmap_sem);
1882                 exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1883                 up_read(&mm->mmap_sem);
1884         }
1885
1886         mmput(mm);
1887
1888         if (exact_vma_exists) {
1889                 if (task_dumpable(task)) {
1890                         rcu_read_lock();
1891                         cred = __task_cred(task);
1892                         inode->i_uid = cred->euid;
1893                         inode->i_gid = cred->egid;
1894                         rcu_read_unlock();
1895                 } else {
1896                         inode->i_uid = GLOBAL_ROOT_UID;
1897                         inode->i_gid = GLOBAL_ROOT_GID;
1898                 }
1899                 security_task_to_inode(task, inode);
1900                 status = 1;
1901         }
1902
1903 out:
1904         put_task_struct(task);
1905
1906 out_notask:
1907         return status;
1908 }
1909
1910 static const struct dentry_operations tid_map_files_dentry_operations = {
1911         .d_revalidate   = map_files_d_revalidate,
1912         .d_delete       = pid_delete_dentry,
1913 };
1914
1915 static int map_files_get_link(struct dentry *dentry, struct path *path)
1916 {
1917         unsigned long vm_start, vm_end;
1918         struct vm_area_struct *vma;
1919         struct task_struct *task;
1920         struct mm_struct *mm;
1921         int rc;
1922
1923         rc = -ENOENT;
1924         task = get_proc_task(d_inode(dentry));
1925         if (!task)
1926                 goto out;
1927
1928         mm = get_task_mm(task);
1929         put_task_struct(task);
1930         if (!mm)
1931                 goto out;
1932
1933         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
1934         if (rc)
1935                 goto out_mmput;
1936
1937         rc = -ENOENT;
1938         down_read(&mm->mmap_sem);
1939         vma = find_exact_vma(mm, vm_start, vm_end);
1940         if (vma && vma->vm_file) {
1941                 *path = vma->vm_file->f_path;
1942                 path_get(path);
1943                 rc = 0;
1944         }
1945         up_read(&mm->mmap_sem);
1946
1947 out_mmput:
1948         mmput(mm);
1949 out:
1950         return rc;
1951 }
1952
1953 struct map_files_info {
1954         fmode_t         mode;
1955         unsigned long   len;
1956         unsigned char   name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
1957 };
1958
1959 /*
1960  * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
1961  * symlinks may be used to bypass permissions on ancestor directories in the
1962  * path to the file in question.
1963  */
1964 static const char *
1965 proc_map_files_get_link(struct dentry *dentry,
1966                         struct inode *inode,
1967                         struct delayed_call *done)
1968 {
1969         if (!capable(CAP_SYS_ADMIN))
1970                 return ERR_PTR(-EPERM);
1971
1972         return proc_pid_get_link(dentry, inode, done);
1973 }
1974
1975 /*
1976  * Identical to proc_pid_link_inode_operations except for get_link()
1977  */
1978 static const struct inode_operations proc_map_files_link_inode_operations = {
1979         .readlink       = proc_pid_readlink,
1980         .get_link       = proc_map_files_get_link,
1981         .setattr        = proc_setattr,
1982 };
1983
1984 static int
1985 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
1986                            struct task_struct *task, const void *ptr)
1987 {
1988         fmode_t mode = (fmode_t)(unsigned long)ptr;
1989         struct proc_inode *ei;
1990         struct inode *inode;
1991
1992         inode = proc_pid_make_inode(dir->i_sb, task);
1993         if (!inode)
1994                 return -ENOENT;
1995
1996         ei = PROC_I(inode);
1997         ei->op.proc_get_link = map_files_get_link;
1998
1999         inode->i_op = &proc_map_files_link_inode_operations;
2000         inode->i_size = 64;
2001         inode->i_mode = S_IFLNK;
2002
2003         if (mode & FMODE_READ)
2004                 inode->i_mode |= S_IRUSR;
2005         if (mode & FMODE_WRITE)
2006                 inode->i_mode |= S_IWUSR;
2007
2008         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2009         d_add(dentry, inode);
2010
2011         return 0;
2012 }
2013
2014 static struct dentry *proc_map_files_lookup(struct inode *dir,
2015                 struct dentry *dentry, unsigned int flags)
2016 {
2017         unsigned long vm_start, vm_end;
2018         struct vm_area_struct *vma;
2019         struct task_struct *task;
2020         int result;
2021         struct mm_struct *mm;
2022
2023         result = -ENOENT;
2024         task = get_proc_task(dir);
2025         if (!task)
2026                 goto out;
2027
2028         result = -EACCES;
2029         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2030                 goto out_put_task;
2031
2032         result = -ENOENT;
2033         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2034                 goto out_put_task;
2035
2036         mm = get_task_mm(task);
2037         if (!mm)
2038                 goto out_put_task;
2039
2040         down_read(&mm->mmap_sem);
2041         vma = find_exact_vma(mm, vm_start, vm_end);
2042         if (!vma)
2043                 goto out_no_vma;
2044
2045         if (vma->vm_file)
2046                 result = proc_map_files_instantiate(dir, dentry, task,
2047                                 (void *)(unsigned long)vma->vm_file->f_mode);
2048
2049 out_no_vma:
2050         up_read(&mm->mmap_sem);
2051         mmput(mm);
2052 out_put_task:
2053         put_task_struct(task);
2054 out:
2055         return ERR_PTR(result);
2056 }
2057
2058 static const struct inode_operations proc_map_files_inode_operations = {
2059         .lookup         = proc_map_files_lookup,
2060         .permission     = proc_fd_permission,
2061         .setattr        = proc_setattr,
2062 };
2063
2064 static int
2065 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2066 {
2067         struct vm_area_struct *vma;
2068         struct task_struct *task;
2069         struct mm_struct *mm;
2070         unsigned long nr_files, pos, i;
2071         struct flex_array *fa = NULL;
2072         struct map_files_info info;
2073         struct map_files_info *p;
2074         int ret;
2075
2076         ret = -ENOENT;
2077         task = get_proc_task(file_inode(file));
2078         if (!task)
2079                 goto out;
2080
2081         ret = -EACCES;
2082         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2083                 goto out_put_task;
2084
2085         ret = 0;
2086         if (!dir_emit_dots(file, ctx))
2087                 goto out_put_task;
2088
2089         mm = get_task_mm(task);
2090         if (!mm)
2091                 goto out_put_task;
2092         down_read(&mm->mmap_sem);
2093
2094         nr_files = 0;
2095
2096         /*
2097          * We need two passes here:
2098          *
2099          *  1) Collect vmas of mapped files with mmap_sem taken
2100          *  2) Release mmap_sem and instantiate entries
2101          *
2102          * otherwise we get lockdep complained, since filldir()
2103          * routine might require mmap_sem taken in might_fault().
2104          */
2105
2106         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2107                 if (vma->vm_file && ++pos > ctx->pos)
2108                         nr_files++;
2109         }
2110
2111         if (nr_files) {
2112                 fa = flex_array_alloc(sizeof(info), nr_files,
2113                                         GFP_KERNEL);
2114                 if (!fa || flex_array_prealloc(fa, 0, nr_files,
2115                                                 GFP_KERNEL)) {
2116                         ret = -ENOMEM;
2117                         if (fa)
2118                                 flex_array_free(fa);
2119                         up_read(&mm->mmap_sem);
2120                         mmput(mm);
2121                         goto out_put_task;
2122                 }
2123                 for (i = 0, vma = mm->mmap, pos = 2; vma;
2124                                 vma = vma->vm_next) {
2125                         if (!vma->vm_file)
2126                                 continue;
2127                         if (++pos <= ctx->pos)
2128                                 continue;
2129
2130                         info.mode = vma->vm_file->f_mode;
2131                         info.len = snprintf(info.name,
2132                                         sizeof(info.name), "%lx-%lx",
2133                                         vma->vm_start, vma->vm_end);
2134                         if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2135                                 BUG();
2136                 }
2137         }
2138         up_read(&mm->mmap_sem);
2139
2140         for (i = 0; i < nr_files; i++) {
2141                 p = flex_array_get(fa, i);
2142                 if (!proc_fill_cache(file, ctx,
2143                                       p->name, p->len,
2144                                       proc_map_files_instantiate,
2145                                       task,
2146                                       (void *)(unsigned long)p->mode))
2147                         break;
2148                 ctx->pos++;
2149         }
2150         if (fa)
2151                 flex_array_free(fa);
2152         mmput(mm);
2153
2154 out_put_task:
2155         put_task_struct(task);
2156 out:
2157         return ret;
2158 }
2159
2160 static const struct file_operations proc_map_files_operations = {
2161         .read           = generic_read_dir,
2162         .iterate_shared = proc_map_files_readdir,
2163         .llseek         = generic_file_llseek,
2164 };
2165
2166 #ifdef CONFIG_CHECKPOINT_RESTORE
2167 struct timers_private {
2168         struct pid *pid;
2169         struct task_struct *task;
2170         struct sighand_struct *sighand;
2171         struct pid_namespace *ns;
2172         unsigned long flags;
2173 };
2174
2175 static void *timers_start(struct seq_file *m, loff_t *pos)
2176 {
2177         struct timers_private *tp = m->private;
2178
2179         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2180         if (!tp->task)
2181                 return ERR_PTR(-ESRCH);
2182
2183         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2184         if (!tp->sighand)
2185                 return ERR_PTR(-ESRCH);
2186
2187         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2188 }
2189
2190 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2191 {
2192         struct timers_private *tp = m->private;
2193         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2194 }
2195
2196 static void timers_stop(struct seq_file *m, void *v)
2197 {
2198         struct timers_private *tp = m->private;
2199
2200         if (tp->sighand) {
2201                 unlock_task_sighand(tp->task, &tp->flags);
2202                 tp->sighand = NULL;
2203         }
2204
2205         if (tp->task) {
2206                 put_task_struct(tp->task);
2207                 tp->task = NULL;
2208         }
2209 }
2210
2211 static int show_timer(struct seq_file *m, void *v)
2212 {
2213         struct k_itimer *timer;
2214         struct timers_private *tp = m->private;
2215         int notify;
2216         static const char * const nstr[] = {
2217                 [SIGEV_SIGNAL] = "signal",
2218                 [SIGEV_NONE] = "none",
2219                 [SIGEV_THREAD] = "thread",
2220         };
2221
2222         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2223         notify = timer->it_sigev_notify;
2224
2225         seq_printf(m, "ID: %d\n", timer->it_id);
2226         seq_printf(m, "signal: %d/%p\n",
2227                    timer->sigq->info.si_signo,
2228                    timer->sigq->info.si_value.sival_ptr);
2229         seq_printf(m, "notify: %s/%s.%d\n",
2230                    nstr[notify & ~SIGEV_THREAD_ID],
2231                    (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2232                    pid_nr_ns(timer->it_pid, tp->ns));
2233         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2234
2235         return 0;
2236 }
2237
2238 static const struct seq_operations proc_timers_seq_ops = {
2239         .start  = timers_start,
2240         .next   = timers_next,
2241         .stop   = timers_stop,
2242         .show   = show_timer,
2243 };
2244
2245 static int proc_timers_open(struct inode *inode, struct file *file)
2246 {
2247         struct timers_private *tp;
2248
2249         tp = __seq_open_private(file, &proc_timers_seq_ops,
2250                         sizeof(struct timers_private));
2251         if (!tp)
2252                 return -ENOMEM;
2253
2254         tp->pid = proc_pid(inode);
2255         tp->ns = inode->i_sb->s_fs_info;
2256         return 0;
2257 }
2258
2259 static const struct file_operations proc_timers_operations = {
2260         .open           = proc_timers_open,
2261         .read           = seq_read,
2262         .llseek         = seq_lseek,
2263         .release        = seq_release_private,
2264 };
2265 #endif
2266
2267 static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2268                                         size_t count, loff_t *offset)
2269 {
2270         struct inode *inode = file_inode(file);
2271         struct task_struct *p;
2272         u64 slack_ns;
2273         int err;
2274
2275         err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2276         if (err < 0)
2277                 return err;
2278
2279         p = get_proc_task(inode);
2280         if (!p)
2281                 return -ESRCH;
2282
2283         if (p != current) {
2284                 if (!capable(CAP_SYS_NICE)) {
2285                         count = -EPERM;
2286                         goto out;
2287                 }
2288
2289                 err = security_task_setscheduler(p);
2290                 if (err) {
2291                         count = err;
2292                         goto out;
2293                 }
2294         }
2295
2296         task_lock(p);
2297         if (slack_ns == 0)
2298                 p->timer_slack_ns = p->default_timer_slack_ns;
2299         else
2300                 p->timer_slack_ns = slack_ns;
2301         task_unlock(p);
2302
2303 out:
2304         put_task_struct(p);
2305
2306         return count;
2307 }
2308
2309 static int timerslack_ns_show(struct seq_file *m, void *v)
2310 {
2311         struct inode *inode = m->private;
2312         struct task_struct *p;
2313         int err = 0;
2314
2315         p = get_proc_task(inode);
2316         if (!p)
2317                 return -ESRCH;
2318
2319         if (p != current) {
2320
2321                 if (!capable(CAP_SYS_NICE)) {
2322                         err = -EPERM;
2323                         goto out;
2324                 }
2325                 err = security_task_getscheduler(p);
2326                 if (err)
2327                         goto out;
2328         }
2329
2330         task_lock(p);
2331         seq_printf(m, "%llu\n", p->timer_slack_ns);
2332         task_unlock(p);
2333
2334 out:
2335         put_task_struct(p);
2336
2337         return err;
2338 }
2339
2340 static int timerslack_ns_open(struct inode *inode, struct file *filp)
2341 {
2342         return single_open(filp, timerslack_ns_show, inode);
2343 }
2344
2345 static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2346         .open           = timerslack_ns_open,
2347         .read           = seq_read,
2348         .write          = timerslack_ns_write,
2349         .llseek         = seq_lseek,
2350         .release        = single_release,
2351 };
2352
2353 static int proc_pident_instantiate(struct inode *dir,
2354         struct dentry *dentry, struct task_struct *task, const void *ptr)
2355 {
2356         const struct pid_entry *p = ptr;
2357         struct inode *inode;
2358         struct proc_inode *ei;
2359
2360         inode = proc_pid_make_inode(dir->i_sb, task);
2361         if (!inode)
2362                 goto out;
2363
2364         ei = PROC_I(inode);
2365         inode->i_mode = p->mode;
2366         if (S_ISDIR(inode->i_mode))
2367                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2368         if (p->iop)
2369                 inode->i_op = p->iop;
2370         if (p->fop)
2371                 inode->i_fop = p->fop;
2372         ei->op = p->op;
2373         d_set_d_op(dentry, &pid_dentry_operations);
2374         d_add(dentry, inode);
2375         /* Close the race of the process dying before we return the dentry */
2376         if (pid_revalidate(dentry, 0))
2377                 return 0;
2378 out:
2379         return -ENOENT;
2380 }
2381
2382 static struct dentry *proc_pident_lookup(struct inode *dir,
2383                                          struct dentry *dentry,
2384                                          const struct pid_entry *ents,
2385                                          unsigned int nents)
2386 {
2387         int error;
2388         struct task_struct *task = get_proc_task(dir);
2389         const struct pid_entry *p, *last;
2390
2391         error = -ENOENT;
2392
2393         if (!task)
2394                 goto out_no_task;
2395
2396         /*
2397          * Yes, it does not scale. And it should not. Don't add
2398          * new entries into /proc/<tgid>/ without very good reasons.
2399          */
2400         last = &ents[nents - 1];
2401         for (p = ents; p <= last; p++) {
2402                 if (p->len != dentry->d_name.len)
2403                         continue;
2404                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2405                         break;
2406         }
2407         if (p > last)
2408                 goto out;
2409
2410         error = proc_pident_instantiate(dir, dentry, task, p);
2411 out:
2412         put_task_struct(task);
2413 out_no_task:
2414         return ERR_PTR(error);
2415 }
2416
2417 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2418                 const struct pid_entry *ents, unsigned int nents)
2419 {
2420         struct task_struct *task = get_proc_task(file_inode(file));
2421         const struct pid_entry *p;
2422
2423         if (!task)
2424                 return -ENOENT;
2425
2426         if (!dir_emit_dots(file, ctx))
2427                 goto out;
2428
2429         if (ctx->pos >= nents + 2)
2430                 goto out;
2431
2432         for (p = ents + (ctx->pos - 2); p <= ents + nents - 1; p++) {
2433                 if (!proc_fill_cache(file, ctx, p->name, p->len,
2434                                 proc_pident_instantiate, task, p))
2435                         break;
2436                 ctx->pos++;
2437         }
2438 out:
2439         put_task_struct(task);
2440         return 0;
2441 }
2442
2443 #ifdef CONFIG_SECURITY
2444 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2445                                   size_t count, loff_t *ppos)
2446 {
2447         struct inode * inode = file_inode(file);
2448         char *p = NULL;
2449         ssize_t length;
2450         struct task_struct *task = get_proc_task(inode);
2451
2452         if (!task)
2453                 return -ESRCH;
2454
2455         length = security_getprocattr(task,
2456                                       (char*)file->f_path.dentry->d_name.name,
2457                                       &p);
2458         put_task_struct(task);
2459         if (length > 0)
2460                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2461         kfree(p);
2462         return length;
2463 }
2464
2465 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2466                                    size_t count, loff_t *ppos)
2467 {
2468         struct inode * inode = file_inode(file);
2469         void *page;
2470         ssize_t length;
2471         struct task_struct *task = get_proc_task(inode);
2472
2473         length = -ESRCH;
2474         if (!task)
2475                 goto out_no_task;
2476         if (count > PAGE_SIZE)
2477                 count = PAGE_SIZE;
2478
2479         /* No partial writes. */
2480         length = -EINVAL;
2481         if (*ppos != 0)
2482                 goto out;
2483
2484         page = memdup_user(buf, count);
2485         if (IS_ERR(page)) {
2486                 length = PTR_ERR(page);
2487                 goto out;
2488         }
2489
2490         /* Guard against adverse ptrace interaction */
2491         length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2492         if (length < 0)
2493                 goto out_free;
2494
2495         length = security_setprocattr(task,
2496                                       (char*)file->f_path.dentry->d_name.name,
2497                                       page, count);
2498         mutex_unlock(&task->signal->cred_guard_mutex);
2499 out_free:
2500         kfree(page);
2501 out:
2502         put_task_struct(task);
2503 out_no_task:
2504         return length;
2505 }
2506
2507 static const struct file_operations proc_pid_attr_operations = {
2508         .read           = proc_pid_attr_read,
2509         .write          = proc_pid_attr_write,
2510         .llseek         = generic_file_llseek,
2511 };
2512
2513 static const struct pid_entry attr_dir_stuff[] = {
2514         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2515         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2516         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2517         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2518         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2519         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2520 };
2521
2522 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2523 {
2524         return proc_pident_readdir(file, ctx,
2525                                    attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2526 }
2527
2528 static const struct file_operations proc_attr_dir_operations = {
2529         .read           = generic_read_dir,
2530         .iterate_shared = proc_attr_dir_readdir,
2531         .llseek         = generic_file_llseek,
2532 };
2533
2534 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2535                                 struct dentry *dentry, unsigned int flags)
2536 {
2537         return proc_pident_lookup(dir, dentry,
2538                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2539 }
2540
2541 static const struct inode_operations proc_attr_dir_inode_operations = {
2542         .lookup         = proc_attr_dir_lookup,
2543         .getattr        = pid_getattr,
2544         .setattr        = proc_setattr,
2545 };
2546
2547 #endif
2548
2549 #ifdef CONFIG_ELF_CORE
2550 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2551                                          size_t count, loff_t *ppos)
2552 {
2553         struct task_struct *task = get_proc_task(file_inode(file));
2554         struct mm_struct *mm;
2555         char buffer[PROC_NUMBUF];
2556         size_t len;
2557         int ret;
2558
2559         if (!task)
2560                 return -ESRCH;
2561
2562         ret = 0;
2563         mm = get_task_mm(task);
2564         if (mm) {
2565                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2566                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2567                                 MMF_DUMP_FILTER_SHIFT));
2568                 mmput(mm);
2569                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2570         }
2571
2572         put_task_struct(task);
2573
2574         return ret;
2575 }
2576
2577 static ssize_t proc_coredump_filter_write(struct file *file,
2578                                           const char __user *buf,
2579                                           size_t count,
2580                                           loff_t *ppos)
2581 {
2582         struct task_struct *task;
2583         struct mm_struct *mm;
2584         unsigned int val;
2585         int ret;
2586         int i;
2587         unsigned long mask;
2588
2589         ret = kstrtouint_from_user(buf, count, 0, &val);
2590         if (ret < 0)
2591                 return ret;
2592
2593         ret = -ESRCH;
2594         task = get_proc_task(file_inode(file));
2595         if (!task)
2596                 goto out_no_task;
2597
2598         mm = get_task_mm(task);
2599         if (!mm)
2600                 goto out_no_mm;
2601         ret = 0;
2602
2603         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2604                 if (val & mask)
2605                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2606                 else
2607                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2608         }
2609
2610         mmput(mm);
2611  out_no_mm:
2612         put_task_struct(task);
2613  out_no_task:
2614         if (ret < 0)
2615                 return ret;
2616         return count;
2617 }
2618
2619 static const struct file_operations proc_coredump_filter_operations = {
2620         .read           = proc_coredump_filter_read,
2621         .write          = proc_coredump_filter_write,
2622         .llseek         = generic_file_llseek,
2623 };
2624 #endif
2625
2626 #ifdef CONFIG_TASK_IO_ACCOUNTING
2627 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2628 {
2629         struct task_io_accounting acct = task->ioac;
2630         unsigned long flags;
2631         int result;
2632
2633         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2634         if (result)
2635                 return result;
2636
2637         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2638                 result = -EACCES;
2639                 goto out_unlock;
2640         }
2641
2642         if (whole && lock_task_sighand(task, &flags)) {
2643                 struct task_struct *t = task;
2644
2645                 task_io_accounting_add(&acct, &task->signal->ioac);
2646                 while_each_thread(task, t)
2647                         task_io_accounting_add(&acct, &t->ioac);
2648
2649                 unlock_task_sighand(task, &flags);
2650         }
2651         seq_printf(m,
2652                    "rchar: %llu\n"
2653                    "wchar: %llu\n"
2654                    "syscr: %llu\n"
2655                    "syscw: %llu\n"
2656                    "read_bytes: %llu\n"
2657                    "write_bytes: %llu\n"
2658                    "cancelled_write_bytes: %llu\n",
2659                    (unsigned long long)acct.rchar,
2660                    (unsigned long long)acct.wchar,
2661                    (unsigned long long)acct.syscr,
2662                    (unsigned long long)acct.syscw,
2663                    (unsigned long long)acct.read_bytes,
2664                    (unsigned long long)acct.write_bytes,
2665                    (unsigned long long)acct.cancelled_write_bytes);
2666         result = 0;
2667
2668 out_unlock:
2669         mutex_unlock(&task->signal->cred_guard_mutex);
2670         return result;
2671 }
2672
2673 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2674                                   struct pid *pid, struct task_struct *task)
2675 {
2676         return do_io_accounting(task, m, 0);
2677 }
2678
2679 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2680                                    struct pid *pid, struct task_struct *task)
2681 {
2682         return do_io_accounting(task, m, 1);
2683 }
2684 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2685
2686 #ifdef CONFIG_USER_NS
2687 static int proc_id_map_open(struct inode *inode, struct file *file,
2688         const struct seq_operations *seq_ops)
2689 {
2690         struct user_namespace *ns = NULL;
2691         struct task_struct *task;
2692         struct seq_file *seq;
2693         int ret = -EINVAL;
2694
2695         task = get_proc_task(inode);
2696         if (task) {
2697                 rcu_read_lock();
2698                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2699                 rcu_read_unlock();
2700                 put_task_struct(task);
2701         }
2702         if (!ns)
2703                 goto err;
2704
2705         ret = seq_open(file, seq_ops);
2706         if (ret)
2707                 goto err_put_ns;
2708
2709         seq = file->private_data;
2710         seq->private = ns;
2711
2712         return 0;
2713 err_put_ns:
2714         put_user_ns(ns);
2715 err:
2716         return ret;
2717 }
2718
2719 static int proc_id_map_release(struct inode *inode, struct file *file)
2720 {
2721         struct seq_file *seq = file->private_data;
2722         struct user_namespace *ns = seq->private;
2723         put_user_ns(ns);
2724         return seq_release(inode, file);
2725 }
2726
2727 static int proc_uid_map_open(struct inode *inode, struct file *file)
2728 {
2729         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2730 }
2731
2732 static int proc_gid_map_open(struct inode *inode, struct file *file)
2733 {
2734         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2735 }
2736
2737 static int proc_projid_map_open(struct inode *inode, struct file *file)
2738 {
2739         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2740 }
2741
2742 static const struct file_operations proc_uid_map_operations = {
2743         .open           = proc_uid_map_open,
2744         .write          = proc_uid_map_write,
2745         .read           = seq_read,
2746         .llseek         = seq_lseek,
2747         .release        = proc_id_map_release,
2748 };
2749
2750 static const struct file_operations proc_gid_map_operations = {
2751         .open           = proc_gid_map_open,
2752         .write          = proc_gid_map_write,
2753         .read           = seq_read,
2754         .llseek         = seq_lseek,
2755         .release        = proc_id_map_release,
2756 };
2757
2758 static const struct file_operations proc_projid_map_operations = {
2759         .open           = proc_projid_map_open,
2760         .write          = proc_projid_map_write,
2761         .read           = seq_read,
2762         .llseek         = seq_lseek,
2763         .release        = proc_id_map_release,
2764 };
2765
2766 static int proc_setgroups_open(struct inode *inode, struct file *file)
2767 {
2768         struct user_namespace *ns = NULL;
2769         struct task_struct *task;
2770         int ret;
2771
2772         ret = -ESRCH;
2773         task = get_proc_task(inode);
2774         if (task) {
2775                 rcu_read_lock();
2776                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2777                 rcu_read_unlock();
2778                 put_task_struct(task);
2779         }
2780         if (!ns)
2781                 goto err;
2782
2783         if (file->f_mode & FMODE_WRITE) {
2784                 ret = -EACCES;
2785                 if (!ns_capable(ns, CAP_SYS_ADMIN))
2786                         goto err_put_ns;
2787         }
2788
2789         ret = single_open(file, &proc_setgroups_show, ns);
2790         if (ret)
2791                 goto err_put_ns;
2792
2793         return 0;
2794 err_put_ns:
2795         put_user_ns(ns);
2796 err:
2797         return ret;
2798 }
2799
2800 static int proc_setgroups_release(struct inode *inode, struct file *file)
2801 {
2802         struct seq_file *seq = file->private_data;
2803         struct user_namespace *ns = seq->private;
2804         int ret = single_release(inode, file);
2805         put_user_ns(ns);
2806         return ret;
2807 }
2808
2809 static const struct file_operations proc_setgroups_operations = {
2810         .open           = proc_setgroups_open,
2811         .write          = proc_setgroups_write,
2812         .read           = seq_read,
2813         .llseek         = seq_lseek,
2814         .release        = proc_setgroups_release,
2815 };
2816 #endif /* CONFIG_USER_NS */
2817
2818 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2819                                 struct pid *pid, struct task_struct *task)
2820 {
2821         int err = lock_trace(task);
2822         if (!err) {
2823                 seq_printf(m, "%08x\n", task->personality);
2824                 unlock_trace(task);
2825         }
2826         return err;
2827 }
2828
2829 /*
2830  * Thread groups
2831  */
2832 static const struct file_operations proc_task_operations;
2833 static const struct inode_operations proc_task_inode_operations;
2834
2835 static const struct pid_entry tgid_base_stuff[] = {
2836         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2837         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2838         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2839         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2840         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2841 #ifdef CONFIG_NET
2842         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2843 #endif
2844         REG("environ",    S_IRUSR, proc_environ_operations),
2845         ONE("auxv",       S_IRUSR, proc_pid_auxv),
2846         ONE("status",     S_IRUGO, proc_pid_status),
2847         ONE("personality", S_IRUSR, proc_pid_personality),
2848         ONE("limits",     S_IRUGO, proc_pid_limits),
2849 #ifdef CONFIG_SCHED_DEBUG
2850         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2851 #endif
2852 #ifdef CONFIG_SCHED_AUTOGROUP
2853         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2854 #endif
2855         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2856 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2857         ONE("syscall",    S_IRUSR, proc_pid_syscall),
2858 #endif
2859         REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
2860         ONE("stat",       S_IRUGO, proc_tgid_stat),
2861         ONE("statm",      S_IRUGO, proc_pid_statm),
2862         REG("maps",       S_IRUGO, proc_pid_maps_operations),
2863 #ifdef CONFIG_NUMA
2864         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2865 #endif
2866         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2867         LNK("cwd",        proc_cwd_link),
2868         LNK("root",       proc_root_link),
2869         LNK("exe",        proc_exe_link),
2870         REG("mounts",     S_IRUGO, proc_mounts_operations),
2871         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2872         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2873 #ifdef CONFIG_PROC_PAGE_MONITOR
2874         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2875         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2876         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2877 #endif
2878 #ifdef CONFIG_SECURITY
2879         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2880 #endif
2881 #ifdef CONFIG_KALLSYMS
2882         ONE("wchan",      S_IRUGO, proc_pid_wchan),
2883 #endif
2884 #ifdef CONFIG_STACKTRACE
2885         ONE("stack",      S_IRUSR, proc_pid_stack),
2886 #endif
2887 #ifdef CONFIG_SCHED_INFO
2888         ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
2889 #endif
2890 #ifdef CONFIG_LATENCYTOP
2891         REG("latency",  S_IRUGO, proc_lstats_operations),
2892 #endif
2893 #ifdef CONFIG_PROC_PID_CPUSET
2894         ONE("cpuset",     S_IRUGO, proc_cpuset_show),
2895 #endif
2896 #ifdef CONFIG_CGROUPS
2897         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
2898 #endif
2899         ONE("oom_score",  S_IRUGO, proc_oom_score),
2900         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
2901         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2902 #ifdef CONFIG_AUDITSYSCALL
2903         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2904         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2905 #endif
2906 #ifdef CONFIG_FAULT_INJECTION
2907         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2908 #endif
2909 #ifdef CONFIG_ELF_CORE
2910         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2911 #endif
2912 #ifdef CONFIG_TASK_IO_ACCOUNTING
2913         ONE("io",       S_IRUSR, proc_tgid_io_accounting),
2914 #endif
2915 #ifdef CONFIG_HARDWALL
2916         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
2917 #endif
2918 #ifdef CONFIG_USER_NS
2919         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
2920         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
2921         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
2922         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
2923 #endif
2924 #ifdef CONFIG_CHECKPOINT_RESTORE
2925         REG("timers",     S_IRUGO, proc_timers_operations),
2926 #endif
2927         REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
2928 };
2929
2930 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
2931 {
2932         return proc_pident_readdir(file, ctx,
2933                                    tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2934 }
2935
2936 static const struct file_operations proc_tgid_base_operations = {
2937         .read           = generic_read_dir,
2938         .iterate_shared = proc_tgid_base_readdir,
2939         .llseek         = generic_file_llseek,
2940 };
2941
2942 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
2943 {
2944         return proc_pident_lookup(dir, dentry,
2945                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2946 }
2947
2948 static const struct inode_operations proc_tgid_base_inode_operations = {
2949         .lookup         = proc_tgid_base_lookup,
2950         .getattr        = pid_getattr,
2951         .setattr        = proc_setattr,
2952         .permission     = proc_pid_permission,
2953 };
2954
2955 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2956 {
2957         struct dentry *dentry, *leader, *dir;
2958         char buf[PROC_NUMBUF];
2959         struct qstr name;
2960
2961         name.name = buf;
2962         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2963         /* no ->d_hash() rejects on procfs */
2964         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2965         if (dentry) {
2966                 d_invalidate(dentry);
2967                 dput(dentry);
2968         }
2969
2970         if (pid == tgid)
2971                 return;
2972
2973         name.name = buf;
2974         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2975         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2976         if (!leader)
2977                 goto out;
2978
2979         name.name = "task";
2980         name.len = strlen(name.name);
2981         dir = d_hash_and_lookup(leader, &name);
2982         if (!dir)
2983                 goto out_put_leader;
2984
2985         name.name = buf;
2986         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2987         dentry = d_hash_and_lookup(dir, &name);
2988         if (dentry) {
2989                 d_invalidate(dentry);
2990                 dput(dentry);
2991         }
2992
2993         dput(dir);
2994 out_put_leader:
2995         dput(leader);
2996 out:
2997         return;
2998 }
2999
3000 /**
3001  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
3002  * @task: task that should be flushed.
3003  *
3004  * When flushing dentries from proc, one needs to flush them from global
3005  * proc (proc_mnt) and from all the namespaces' procs this task was seen
3006  * in. This call is supposed to do all of this job.
3007  *
3008  * Looks in the dcache for
3009  * /proc/@pid
3010  * /proc/@tgid/task/@pid
3011  * if either directory is present flushes it and all of it'ts children
3012  * from the dcache.
3013  *
3014  * It is safe and reasonable to cache /proc entries for a task until
3015  * that task exits.  After that they just clog up the dcache with
3016  * useless entries, possibly causing useful dcache entries to be
3017  * flushed instead.  This routine is proved to flush those useless
3018  * dcache entries at process exit time.
3019  *
3020  * NOTE: This routine is just an optimization so it does not guarantee
3021  *       that no dcache entries will exist at process exit time it
3022  *       just makes it very unlikely that any will persist.
3023  */
3024
3025 void proc_flush_task(struct task_struct *task)
3026 {
3027         int i;
3028         struct pid *pid, *tgid;
3029         struct upid *upid;
3030
3031         pid = task_pid(task);
3032         tgid = task_tgid(task);
3033
3034         for (i = 0; i <= pid->level; i++) {
3035                 upid = &pid->numbers[i];
3036                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3037                                         tgid->numbers[i].nr);
3038         }
3039 }
3040
3041 static int proc_pid_instantiate(struct inode *dir,
3042                                    struct dentry * dentry,
3043                                    struct task_struct *task, const void *ptr)
3044 {
3045         struct inode *inode;
3046
3047         inode = proc_pid_make_inode(dir->i_sb, task);
3048         if (!inode)
3049                 goto out;
3050
3051         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3052         inode->i_op = &proc_tgid_base_inode_operations;
3053         inode->i_fop = &proc_tgid_base_operations;
3054         inode->i_flags|=S_IMMUTABLE;
3055
3056         set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
3057                                                   ARRAY_SIZE(tgid_base_stuff)));
3058
3059         d_set_d_op(dentry, &pid_dentry_operations);
3060
3061         d_add(dentry, inode);
3062         /* Close the race of the process dying before we return the dentry */
3063         if (pid_revalidate(dentry, 0))
3064                 return 0;
3065 out:
3066         return -ENOENT;
3067 }
3068
3069 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3070 {
3071         int result = -ENOENT;
3072         struct task_struct *task;
3073         unsigned tgid;
3074         struct pid_namespace *ns;
3075
3076         tgid = name_to_int(&dentry->d_name);
3077         if (tgid == ~0U)
3078                 goto out;
3079
3080         ns = dentry->d_sb->s_fs_info;
3081         rcu_read_lock();
3082         task = find_task_by_pid_ns(tgid, ns);
3083         if (task)
3084                 get_task_struct(task);
3085         rcu_read_unlock();
3086         if (!task)
3087                 goto out;
3088
3089         result = proc_pid_instantiate(dir, dentry, task, NULL);
3090         put_task_struct(task);
3091 out:
3092         return ERR_PTR(result);
3093 }
3094
3095 /*
3096  * Find the first task with tgid >= tgid
3097  *
3098  */
3099 struct tgid_iter {
3100         unsigned int tgid;
3101         struct task_struct *task;
3102 };
3103 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3104 {
3105         struct pid *pid;
3106
3107         if (iter.task)
3108                 put_task_struct(iter.task);
3109         rcu_read_lock();
3110 retry:
3111         iter.task = NULL;
3112         pid = find_ge_pid(iter.tgid, ns);
3113         if (pid) {
3114                 iter.tgid = pid_nr_ns(pid, ns);
3115                 iter.task = pid_task(pid, PIDTYPE_PID);
3116                 /* What we to know is if the pid we have find is the
3117                  * pid of a thread_group_leader.  Testing for task
3118                  * being a thread_group_leader is the obvious thing
3119                  * todo but there is a window when it fails, due to
3120                  * the pid transfer logic in de_thread.
3121                  *
3122                  * So we perform the straight forward test of seeing
3123                  * if the pid we have found is the pid of a thread
3124                  * group leader, and don't worry if the task we have
3125                  * found doesn't happen to be a thread group leader.
3126                  * As we don't care in the case of readdir.
3127                  */
3128                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3129                         iter.tgid += 1;
3130                         goto retry;
3131                 }
3132                 get_task_struct(iter.task);
3133         }
3134         rcu_read_unlock();
3135         return iter;
3136 }
3137
3138 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3139
3140 /* for the /proc/ directory itself, after non-process stuff has been done */
3141 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3142 {
3143         struct tgid_iter iter;
3144         struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info;
3145         loff_t pos = ctx->pos;
3146
3147         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3148                 return 0;
3149
3150         if (pos == TGID_OFFSET - 2) {
3151                 struct inode *inode = d_inode(ns->proc_self);
3152                 if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3153                         return 0;
3154                 ctx->pos = pos = pos + 1;
3155         }
3156         if (pos == TGID_OFFSET - 1) {
3157                 struct inode *inode = d_inode(ns->proc_thread_self);
3158                 if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3159                         return 0;
3160                 ctx->pos = pos = pos + 1;
3161         }
3162         iter.tgid = pos - TGID_OFFSET;
3163         iter.task = NULL;
3164         for (iter = next_tgid(ns, iter);
3165              iter.task;
3166              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3167                 char name[PROC_NUMBUF];
3168                 int len;
3169                 if (!has_pid_permissions(ns, iter.task, 2))
3170                         continue;
3171
3172                 len = snprintf(name, sizeof(name), "%d", iter.tgid);
3173                 ctx->pos = iter.tgid + TGID_OFFSET;
3174                 if (!proc_fill_cache(file, ctx, name, len,
3175                                      proc_pid_instantiate, iter.task, NULL)) {
3176                         put_task_struct(iter.task);
3177                         return 0;
3178                 }
3179         }
3180         ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3181         return 0;
3182 }
3183
3184 /*
3185  * proc_tid_comm_permission is a special permission function exclusively
3186  * used for the node /proc/<pid>/task/<tid>/comm.
3187  * It bypasses generic permission checks in the case where a task of the same
3188  * task group attempts to access the node.
3189  * The rationale behind this is that glibc and bionic access this node for
3190  * cross thread naming (pthread_set/getname_np(!self)). However, if
3191  * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3192  * which locks out the cross thread naming implementation.
3193  * This function makes sure that the node is always accessible for members of
3194  * same thread group.
3195  */
3196 static int proc_tid_comm_permission(struct inode *inode, int mask)
3197 {
3198         bool is_same_tgroup;
3199         struct task_struct *task;
3200
3201         task = get_proc_task(inode);
3202         if (!task)
3203                 return -ESRCH;
3204         is_same_tgroup = same_thread_group(current, task);
3205         put_task_struct(task);
3206
3207         if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3208                 /* This file (/proc/<pid>/task/<tid>/comm) can always be
3209                  * read or written by the members of the corresponding
3210                  * thread group.
3211                  */
3212                 return 0;
3213         }
3214
3215         return generic_permission(inode, mask);
3216 }
3217
3218 static const struct inode_operations proc_tid_comm_inode_operations = {
3219                 .permission = proc_tid_comm_permission,
3220 };
3221
3222 /*
3223  * Tasks
3224  */
3225 static const struct pid_entry tid_base_stuff[] = {
3226         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3227         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3228         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3229 #ifdef CONFIG_NET
3230         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3231 #endif
3232         REG("environ",   S_IRUSR, proc_environ_operations),
3233         ONE("auxv",      S_IRUSR, proc_pid_auxv),
3234         ONE("status",    S_IRUGO, proc_pid_status),
3235         ONE("personality", S_IRUSR, proc_pid_personality),
3236         ONE("limits",    S_IRUGO, proc_pid_limits),
3237 #ifdef CONFIG_SCHED_DEBUG
3238         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3239 #endif
3240         NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3241                          &proc_tid_comm_inode_operations,
3242                          &proc_pid_set_comm_operations, {}),
3243 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3244         ONE("syscall",   S_IRUSR, proc_pid_syscall),
3245 #endif
3246         REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3247         ONE("stat",      S_IRUGO, proc_tid_stat),
3248         ONE("statm",     S_IRUGO, proc_pid_statm),
3249         REG("maps",      S_IRUGO, proc_tid_maps_operations),
3250 #ifdef CONFIG_PROC_CHILDREN
3251         REG("children",  S_IRUGO, proc_tid_children_operations),
3252 #endif
3253 #ifdef CONFIG_NUMA
3254         REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3255 #endif
3256         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3257         LNK("cwd",       proc_cwd_link),
3258         LNK("root",      proc_root_link),
3259         LNK("exe",       proc_exe_link),
3260         REG("mounts",    S_IRUGO, proc_mounts_operations),
3261         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3262 #ifdef CONFIG_PROC_PAGE_MONITOR
3263         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3264         REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3265         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3266 #endif
3267 #ifdef CONFIG_SECURITY
3268         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3269 #endif
3270 #ifdef CONFIG_KALLSYMS
3271         ONE("wchan",     S_IRUGO, proc_pid_wchan),
3272 #endif
3273 #ifdef CONFIG_STACKTRACE
3274         ONE("stack",      S_IRUSR, proc_pid_stack),
3275 #endif
3276 #ifdef CONFIG_SCHED_INFO
3277         ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3278 #endif
3279 #ifdef CONFIG_LATENCYTOP
3280         REG("latency",  S_IRUGO, proc_lstats_operations),
3281 #endif
3282 #ifdef CONFIG_PROC_PID_CPUSET
3283         ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3284 #endif
3285 #ifdef CONFIG_CGROUPS
3286         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3287 #endif
3288         ONE("oom_score", S_IRUGO, proc_oom_score),
3289         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3290         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3291 #ifdef CONFIG_AUDITSYSCALL
3292         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3293         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3294 #endif
3295 #ifdef CONFIG_FAULT_INJECTION
3296         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3297 #endif
3298 #ifdef CONFIG_TASK_IO_ACCOUNTING
3299         ONE("io",       S_IRUSR, proc_tid_io_accounting),
3300 #endif
3301 #ifdef CONFIG_HARDWALL
3302         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
3303 #endif
3304 #ifdef CONFIG_USER_NS
3305         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3306         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3307         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3308         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3309 #endif
3310 };
3311
3312 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3313 {
3314         return proc_pident_readdir(file, ctx,
3315                                    tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3316 }
3317
3318 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3319 {
3320         return proc_pident_lookup(dir, dentry,
3321                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3322 }
3323
3324 static const struct file_operations proc_tid_base_operations = {
3325         .read           = generic_read_dir,
3326         .iterate_shared = proc_tid_base_readdir,
3327         .llseek         = generic_file_llseek,
3328 };
3329
3330 static const struct inode_operations proc_tid_base_inode_operations = {
3331         .lookup         = proc_tid_base_lookup,
3332         .getattr        = pid_getattr,
3333         .setattr        = proc_setattr,
3334 };
3335
3336 static int proc_task_instantiate(struct inode *dir,
3337         struct dentry *dentry, struct task_struct *task, const void *ptr)
3338 {
3339         struct inode *inode;
3340         inode = proc_pid_make_inode(dir->i_sb, task);
3341
3342         if (!inode)
3343                 goto out;
3344         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3345         inode->i_op = &proc_tid_base_inode_operations;
3346         inode->i_fop = &proc_tid_base_operations;
3347         inode->i_flags|=S_IMMUTABLE;
3348
3349         set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
3350                                                   ARRAY_SIZE(tid_base_stuff)));
3351
3352         d_set_d_op(dentry, &pid_dentry_operations);
3353
3354         d_add(dentry, inode);
3355         /* Close the race of the process dying before we return the dentry */
3356         if (pid_revalidate(dentry, 0))
3357                 return 0;
3358 out:
3359         return -ENOENT;
3360 }
3361
3362 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3363 {
3364         int result = -ENOENT;
3365         struct task_struct *task;
3366         struct task_struct *leader = get_proc_task(dir);
3367         unsigned tid;
3368         struct pid_namespace *ns;
3369
3370         if (!leader)
3371                 goto out_no_task;
3372
3373         tid = name_to_int(&dentry->d_name);
3374         if (tid == ~0U)
3375                 goto out;
3376
3377         ns = dentry->d_sb->s_fs_info;
3378         rcu_read_lock();
3379         task = find_task_by_pid_ns(tid, ns);
3380         if (task)
3381                 get_task_struct(task);
3382         rcu_read_unlock();
3383         if (!task)
3384                 goto out;
3385         if (!same_thread_group(leader, task))
3386                 goto out_drop_task;
3387
3388         result = proc_task_instantiate(dir, dentry, task, NULL);
3389 out_drop_task:
3390         put_task_struct(task);
3391 out:
3392         put_task_struct(leader);
3393 out_no_task:
3394         return ERR_PTR(result);
3395 }
3396
3397 /*
3398  * Find the first tid of a thread group to return to user space.
3399  *
3400  * Usually this is just the thread group leader, but if the users
3401  * buffer was too small or there was a seek into the middle of the
3402  * directory we have more work todo.
3403  *
3404  * In the case of a short read we start with find_task_by_pid.
3405  *
3406  * In the case of a seek we start with the leader and walk nr
3407  * threads past it.
3408  */
3409 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3410                                         struct pid_namespace *ns)
3411 {
3412         struct task_struct *pos, *task;
3413         unsigned long nr = f_pos;
3414
3415         if (nr != f_pos)        /* 32bit overflow? */
3416                 return NULL;
3417
3418         rcu_read_lock();
3419         task = pid_task(pid, PIDTYPE_PID);
3420         if (!task)
3421                 goto fail;
3422
3423         /* Attempt to start with the tid of a thread */
3424         if (tid && nr) {
3425                 pos = find_task_by_pid_ns(tid, ns);
3426                 if (pos && same_thread_group(pos, task))
3427                         goto found;
3428         }
3429
3430         /* If nr exceeds the number of threads there is nothing todo */
3431         if (nr >= get_nr_threads(task))
3432                 goto fail;
3433
3434         /* If we haven't found our starting place yet start
3435          * with the leader and walk nr threads forward.
3436          */
3437         pos = task = task->group_leader;
3438         do {
3439                 if (!nr--)
3440                         goto found;
3441         } while_each_thread(task, pos);
3442 fail:
3443         pos = NULL;
3444         goto out;
3445 found:
3446         get_task_struct(pos);
3447 out:
3448         rcu_read_unlock();
3449         return pos;
3450 }
3451
3452 /*
3453  * Find the next thread in the thread list.
3454  * Return NULL if there is an error or no next thread.
3455  *
3456  * The reference to the input task_struct is released.
3457  */
3458 static struct task_struct *next_tid(struct task_struct *start)
3459 {
3460         struct task_struct *pos = NULL;
3461         rcu_read_lock();
3462         if (pid_alive(start)) {
3463                 pos = next_thread(start);
3464                 if (thread_group_leader(pos))
3465                         pos = NULL;
3466                 else
3467                         get_task_struct(pos);
3468         }
3469         rcu_read_unlock();
3470         put_task_struct(start);
3471         return pos;
3472 }
3473
3474 /* for the /proc/TGID/task/ directories */
3475 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3476 {
3477         struct inode *inode = file_inode(file);
3478         struct task_struct *task;
3479         struct pid_namespace *ns;
3480         int tid;
3481
3482         if (proc_inode_is_dead(inode))
3483                 return -ENOENT;
3484
3485         if (!dir_emit_dots(file, ctx))
3486                 return 0;
3487
3488         /* f_version caches the tgid value that the last readdir call couldn't
3489          * return. lseek aka telldir automagically resets f_version to 0.
3490          */
3491         ns = inode->i_sb->s_fs_info;
3492         tid = (int)file->f_version;
3493         file->f_version = 0;
3494         for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3495              task;
3496              task = next_tid(task), ctx->pos++) {
3497                 char name[PROC_NUMBUF];
3498                 int len;
3499                 tid = task_pid_nr_ns(task, ns);
3500                 len = snprintf(name, sizeof(name), "%d", tid);
3501                 if (!proc_fill_cache(file, ctx, name, len,
3502                                 proc_task_instantiate, task, NULL)) {
3503                         /* returning this tgid failed, save it as the first
3504                          * pid for the next readir call */
3505                         file->f_version = (u64)tid;
3506                         put_task_struct(task);
3507                         break;
3508                 }
3509         }
3510
3511         return 0;
3512 }
3513
3514 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3515 {
3516         struct inode *inode = d_inode(dentry);
3517         struct task_struct *p = get_proc_task(inode);
3518         generic_fillattr(inode, stat);
3519
3520         if (p) {
3521                 stat->nlink += get_nr_threads(p);
3522                 put_task_struct(p);
3523         }
3524
3525         return 0;
3526 }
3527
3528 static const struct inode_operations proc_task_inode_operations = {
3529         .lookup         = proc_task_lookup,
3530         .getattr        = proc_task_getattr,
3531         .setattr        = proc_setattr,
3532         .permission     = proc_pid_permission,
3533 };
3534
3535 static const struct file_operations proc_task_operations = {
3536         .read           = generic_read_dir,
3537         .iterate_shared = proc_task_readdir,
3538         .llseek         = generic_file_llseek,
3539 };