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