fs/proc/base.c

   1 /*
   2  *  linux/fs/proc/base.c
   3  *
   4  *  Copyright (C) 1991, 1992 Linus Torvalds
   5  *
   6  *  proc base directory handling functions
   7  *
   8  *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
   9  *  Instead of using magical inumbers to determine the kind of object
  10  *  we allocate and fill in-core inodes upon lookup. They don't even
  11  *  go into icache. We cache the reference to task_struct upon lookup too.
  12  *  Eventually it should become a filesystem in its own. We don't use the
  13  *  rest of procfs anymore.
  14  *
  15  *
  16  *  Changelog:
  17  *  17-Jan-2005
  18  *  Allan Bezerra
  19  *  Bruna Moreira <bruna.moreira@indt.org.br>
  20  *  Edjard Mota <edjard.mota@indt.org.br>
  21  *  Ilias Biris <ilias.biris@indt.org.br>
  22  *  Mauricio Lin <mauricio.lin@indt.org.br>
  23  *
  24  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  25  *
  26  *  A new process specific entry (smaps) included in /proc. It shows the
  27  *  size of rss for each memory area. The maps entry lacks information
  28  *  about physical memory size (rss) for each mapped file, i.e.,
  29  *  rss information for executables and library files.
  30  *  This additional information is useful for any tools that need to know
  31  *  about physical memory consumption for a process specific library.
  32  *
  33  *  Changelog:
  34  *  21-Feb-2005
  35  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
  36  *  Pud inclusion in the page table walking.
  37  *
  38  *  ChangeLog:
  39  *  10-Mar-2005
  40  *  10LE Instituto Nokia de Tecnologia - INdT:
  41  *  A better way to walks through the page table as suggested by Hugh Dickins.
  42  *
  43  *  Simo Piiroinen <simo.piiroinen@nokia.com>:
  44  *  Smaps information related to shared, private, clean and dirty pages.
  45  *
  46  *  Paul Mundt <paul.mundt@nokia.com>:
  47  *  Overall revision about smaps.
  48  */
  49
  50 #include <asm/uaccess.h>
  51
  52 #include <linux/errno.h>
  53 #include <linux/time.h>
  54 #include <linux/proc_fs.h>
  55 #include <linux/stat.h>
  56 #include <linux/task_io_accounting_ops.h>
  57 #include <linux/init.h>
  58 #include <linux/capability.h>
  59 #include <linux/file.h>
  60 #include <linux/fdtable.h>
  61 #include <linux/string.h>
  62 #include <linux/seq_file.h>
  63 #include <linux/namei.h>
  64 #include <linux/mnt_namespace.h>
  65 #include <linux/mm.h>
  66 #include <linux/swap.h>
  67 #include <linux/rcupdate.h>
  68 #include <linux/kallsyms.h>
  69 #include <linux/stacktrace.h>
  70 #include <linux/resource.h>
  71 #include <linux/module.h>
  72 #include <linux/mount.h>
  73 #include <linux/security.h>
  74 #include <linux/ptrace.h>
  75 #include <linux/tracehook.h>
  76 #include <linux/printk.h>
  77 #include <linux/cgroup.h>
  78 #include <linux/cpuset.h>
  79 #include <linux/audit.h>
  80 #include <linux/poll.h>
  81 #include <linux/nsproxy.h>
  82 #include <linux/oom.h>
  83 #include <linux/elf.h>
  84 #include <linux/pid_namespace.h>
  85 #include <linux/user_namespace.h>
  86 #include <linux/fs_struct.h>
  87 #include <linux/slab.h>
  88 #include <linux/flex_array.h>
  89 #include <linux/posix-timers.h>
  90 #ifdef CONFIG_HARDWALL
  91 #include <asm/hardwall.h>
  92 #endif
  93 #include <trace/events/oom.h>
  94 #include "internal.h"
  95 #include "fd.h"
  96
  97 /* NOTE:
  98  *      Implementing inode permission operations in /proc is almost
  99  *      certainly an error.  Permission checks need to happen during
 100  *      each system call not at open time.  The reason is that most of
 101  *      what we wish to check for permissions in /proc varies at runtime.
 102  *
 103  *      The classic example of a problem is opening file descriptors
 104  *      in /proc for a task before it execs a suid executable.
 105  */
 106
 107 struct pid_entry {
 108         const char *name;
 109         int len;
 110         umode_t mode;
 111         const struct inode_operations *iop;
 112         const struct file_operations *fop;
 113         union proc_op op;
 114 };
 115
 116 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 117         .name = (NAME),                                 \
 118         .len  = sizeof(NAME) - 1,                       \
 119         .mode = MODE,                                   \
 120         .iop  = IOP,                                    \
 121         .fop  = FOP,                                    \
 122         .op   = OP,                                     \
 123 }
 124
 125 #define DIR(NAME, MODE, iops, fops)     \
 126         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 127 #define LNK(NAME, get_link)                                     \
 128         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 129                 &proc_pid_link_inode_operations, NULL,          \
 130                 { .proc_get_link = get_link } )
 131 #define REG(NAME, MODE, fops)                           \
 132         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 133 #define ONE(NAME, MODE, show)                           \
 134         NOD(NAME, (S_IFREG|(MODE)),                     \
 135                 NULL, &proc_single_file_operations,     \
 136                 { .proc_show = show } )
 137
 138 /*
 139  * Count the number of hardlinks for the pid_entry table, excluding the .
 140  * and .. links.
 141  */
 142 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
 143         unsigned int n)
 144 {
 145         unsigned int i;
 146         unsigned int count;
 147
 148         count = 0;
 149         for (i = 0; i < n; ++i) {
 150                 if (S_ISDIR(entries[i].mode))
 151                         ++count;
 152         }
 153
 154         return count;
 155 }
 156
 157 static int get_task_root(struct task_struct *task, struct path *root)
 158 {
 159         int result = -ENOENT;
 160
 161         task_lock(task);
 162         if (task->fs) {
 163                 get_fs_root(task->fs, root);
 164                 result = 0;
 165         }
 166         task_unlock(task);
 167         return result;
 168 }
 169
 170 static int proc_cwd_link(struct dentry *dentry, struct path *path)
 171 {
 172         struct task_struct *task = get_proc_task(d_inode(dentry));
 173         int result = -ENOENT;
 174
 175         if (task) {
 176                 task_lock(task);
 177                 if (task->fs) {
 178                         get_fs_pwd(task->fs, path);
 179                         result = 0;
 180                 }
 181                 task_unlock(task);
 182                 put_task_struct(task);
 183         }
 184         return result;
 185 }
 186
 187 static int proc_root_link(struct dentry *dentry, struct path *path)
 188 {
 189         struct task_struct *task = get_proc_task(d_inode(dentry));
 190         int result = -ENOENT;
 191
 192         if (task) {
 193                 result = get_task_root(task, path);
 194                 put_task_struct(task);
 195         }
 196         return result;
 197 }
 198
 199 static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 200                                      size_t _count, loff_t *pos)
 201 {
 202         struct task_struct *tsk;
 203         struct mm_struct *mm;
 204         char *page;
 205         unsigned long count = _count;
 206         unsigned long arg_start, arg_end, env_start, env_end;
 207         unsigned long len1, len2, len;
 208         unsigned long p;
 209         char c;
 210         ssize_t rv;
 211
 212         BUG_ON(*pos < 0);
 213
 214         tsk = get_proc_task(file_inode(file));
 215         if (!tsk)
 216                 return -ESRCH;
 217         mm = get_task_mm(tsk);
 218         put_task_struct(tsk);
 219         if (!mm)
 220                 return 0;
 221         /* Check if process spawned far enough to have cmdline. */
 222         if (!mm->env_end) {
 223                 rv = 0;
 224                 goto out_mmput;
 225         }
 226
 227         page = (char *)__get_free_page(GFP_TEMPORARY);
 228         if (!page) {
 229                 rv = -ENOMEM;
 230                 goto out_mmput;
 231         }
 232
 233         down_read(&mm->mmap_sem);
 234         arg_start = mm->arg_start;
 235         arg_end = mm->arg_end;
 236         env_start = mm->env_start;
 237         env_end = mm->env_end;
 238         up_read(&mm->mmap_sem);
 239
 240         BUG_ON(arg_start > arg_end);
 241         BUG_ON(env_start > env_end);
 242
 243         len1 = arg_end - arg_start;
 244         len2 = env_end - env_start;
 245
 246         /* Empty ARGV. */
 247         if (len1 == 0) {
 248                 rv = 0;
 249                 goto out_free_page;
 250         }
 251         /*
 252          * Inherently racy -- command line shares address space
 253          * with code and data.
 254          */
 255         rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0);
 256         if (rv <= 0)
 257                 goto out_free_page;
 258
 259         rv = 0;
 260
 261         if (c == '\0') {
 262                 /* Command line (set of strings) occupies whole ARGV. */
 263                 if (len1 <= *pos)
 264                         goto out_free_page;
 265
 266                 p = arg_start + *pos;
 267                 len = len1 - *pos;
 268                 while (count > 0 && len > 0) {
 269                         unsigned int _count;
 270                         int nr_read;
 271
 272                         _count = min3(count, len, PAGE_SIZE);
 273                         nr_read = access_remote_vm(mm, p, page, _count, 0);
 274                         if (nr_read < 0)
 275                                 rv = nr_read;
 276                         if (nr_read <= 0)
 277                                 goto out_free_page;
 278
 279                         if (copy_to_user(buf, page, nr_read)) {
 280                                 rv = -EFAULT;
 281                                 goto out_free_page;
 282                         }
 283
 284                         p       += nr_read;
 285                         len     -= nr_read;
 286                         buf     += nr_read;
 287                         count   -= nr_read;
 288                         rv      += nr_read;
 289                 }
 290         } else {
 291                 /*
 292                  * Command line (1 string) occupies ARGV and maybe
 293                  * extends into ENVP.
 294                  */
 295                 if (len1 + len2 <= *pos)
 296                         goto skip_argv_envp;
 297                 if (len1 <= *pos)
 298                         goto skip_argv;
 299
 300                 p = arg_start + *pos;
 301                 len = len1 - *pos;
 302                 while (count > 0 && len > 0) {
 303                         unsigned int _count, l;
 304                         int nr_read;
 305                         bool final;
 306
 307                         _count = min3(count, len, PAGE_SIZE);
 308                         nr_read = access_remote_vm(mm, p, page, _count, 0);
 309                         if (nr_read < 0)
 310                                 rv = nr_read;
 311                         if (nr_read <= 0)
 312                                 goto out_free_page;
 313
 314                         /*
 315                          * Command line can be shorter than whole ARGV
 316                          * even if last "marker" byte says it is not.
 317                          */
 318                         final = false;
 319                         l = strnlen(page, nr_read);
 320                         if (l < nr_read) {
 321                                 nr_read = l;
 322                                 final = true;
 323                         }
 324
 325                         if (copy_to_user(buf, page, nr_read)) {
 326                                 rv = -EFAULT;
 327                                 goto out_free_page;
 328                         }
 329
 330                         p       += nr_read;
 331                         len     -= nr_read;
 332                         buf     += nr_read;
 333                         count   -= nr_read;
 334                         rv      += nr_read;
 335
 336                         if (final)
 337                                 goto out_free_page;
 338                 }
 339 skip_argv:
 340                 /*
 341                  * Command line (1 string) occupies ARGV and
 342                  * extends into ENVP.
 343                  */
 344                 if (len1 <= *pos) {
 345                         p = env_start + *pos - len1;
 346                         len = len1 + len2 - *pos;
 347                 } else {
 348                         p = env_start;
 349                         len = len2;
 350                 }
 351                 while (count > 0 && len > 0) {
 352                         unsigned int _count, l;
 353                         int nr_read;
 354                         bool final;
 355
 356                         _count = min3(count, len, PAGE_SIZE);
 357                         nr_read = access_remote_vm(mm, p, page, _count, 0);
 358                         if (nr_read < 0)
 359                                 rv = nr_read;
 360                         if (nr_read <= 0)
 361                                 goto out_free_page;
 362
 363                         /* Find EOS. */
 364                         final = false;
 365                         l = strnlen(page, nr_read);
 366                         if (l < nr_read) {
 367                                 nr_read = l;
 368                                 final = true;
 369                         }
 370
 371                         if (copy_to_user(buf, page, nr_read)) {
 372                                 rv = -EFAULT;
 373                                 goto out_free_page;
 374                         }
 375
 376                         p       += nr_read;
 377                         len     -= nr_read;
 378                         buf     += nr_read;
 379                         count   -= nr_read;
 380                         rv      += nr_read;
 381
 382                         if (final)
 383                                 goto out_free_page;
 384                 }
 385 skip_argv_envp:
 386                 ;
 387         }
 388
 389 out_free_page:
 390         free_page((unsigned long)page);
 391 out_mmput:
 392         mmput(mm);
 393         if (rv > 0)
 394                 *pos += rv;
 395         return rv;
 396 }
 397
 398 static const struct file_operations proc_pid_cmdline_ops = {
 399         .read   = proc_pid_cmdline_read,
 400         .llseek = generic_file_llseek,
 401 };
 402
 403 static int proc_pid_auxv(struct seq_file *m, struct pid_namespace *ns,
 404                          struct pid *pid, struct task_struct *task)
 405 {
 406         struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
 407         if (mm && !IS_ERR(mm)) {
 408                 unsigned int nwords = 0;
 409                 do {
 410                         nwords += 2;
 411                 } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 412                 seq_write(m, mm->saved_auxv, nwords * sizeof(mm->saved_auxv[0]));
 413                 mmput(mm);
 414                 return 0;
 415         } else
 416                 return PTR_ERR(mm);
 417 }
 418
 419
 420 #ifdef CONFIG_KALLSYMS
 421 /*
 422  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 423  * Returns the resolved symbol.  If that fails, simply return the address.
 424  */
 425 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
 426                           struct pid *pid, struct task_struct *task)
 427 {
 428         unsigned long wchan;
 429         char symname[KSYM_NAME_LEN];
 430
 431         wchan = get_wchan(task);
 432
 433         if (wchan && ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)
 434                         && !lookup_symbol_name(wchan, symname))
 435                 seq_printf(m, "%s", symname);
 436         else
 437                 seq_putc(m, '0');
 438
 439         return 0;
 440 }
 441 #endif /* CONFIG_KALLSYMS */
 442
 443 static int lock_trace(struct task_struct *task)
 444 {
 445         int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
 446         if (err)
 447                 return err;
 448         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
 449                 mutex_unlock(&task->signal->cred_guard_mutex);
 450                 return -EPERM;
 451         }
 452         return 0;
 453 }
 454
 455 static void unlock_trace(struct task_struct *task)
 456 {
 457         mutex_unlock(&task->signal->cred_guard_mutex);
 458 }
 459
 460 #ifdef CONFIG_STACKTRACE
 461
 462 #define MAX_STACK_TRACE_DEPTH   64
 463
 464 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 465                           struct pid *pid, struct task_struct *task)
 466 {
 467         struct stack_trace trace;
 468         unsigned long *entries;
 469         int err;
 470         int i;
 471
 472         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 473         if (!entries)
 474                 return -ENOMEM;
 475
 476         trace.nr_entries        = 0;
 477         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 478         trace.entries           = entries;
 479         trace.skip              = 0;
 480
 481         err = lock_trace(task);
 482         if (!err) {
 483                 save_stack_trace_tsk(task, &trace);
 484
 485                 for (i = 0; i < trace.nr_entries; i++) {
 486                         seq_printf(m, "[<%pK>] %pS\n",
 487                                    (void *)entries[i], (void *)entries[i]);
 488                 }
 489                 unlock_trace(task);
 490         }
 491         kfree(entries);
 492
 493         return err;
 494 }
 495 #endif
 496
 497 #ifdef CONFIG_SCHED_INFO
 498 /*
 499  * Provides /proc/PID/schedstat
 500  */
 501 static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 502                               struct pid *pid, struct task_struct *task)
 503 {
 504         if (unlikely(!sched_info_on()))
 505                 seq_printf(m, "0 0 0\n");
 506         else
 507                 seq_printf(m, "%llu %llu %lu\n",
 508                    (unsigned long long)task->se.sum_exec_runtime,
 509                    (unsigned long long)task->sched_info.run_delay,
 510                    task->sched_info.pcount);
 511
 512         return 0;
 513 }
 514 #endif
 515
 516 #ifdef CONFIG_LATENCYTOP
 517 static int lstats_show_proc(struct seq_file *m, void *v)
 518 {
 519         int i;
 520         struct inode *inode = m->private;
 521         struct task_struct *task = get_proc_task(inode);
 522
 523         if (!task)
 524                 return -ESRCH;
 525         seq_puts(m, "Latency Top version : v0.1\n");
 526         for (i = 0; i < 32; i++) {
 527                 struct latency_record *lr = &task->latency_record[i];
 528                 if (lr->backtrace[0]) {
 529                         int q;
 530                         seq_printf(m, "%i %li %li",
 531                                    lr->count, lr->time, lr->max);
 532                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 533                                 unsigned long bt = lr->backtrace[q];
 534                                 if (!bt)
 535                                         break;
 536                                 if (bt == ULONG_MAX)
 537                                         break;
 538                                 seq_printf(m, " %ps", (void *)bt);
 539                         }
 540                         seq_putc(m, '\n');
 541                 }
 542
 543         }
 544         put_task_struct(task);
 545         return 0;
 546 }
 547
 548 static int lstats_open(struct inode *inode, struct file *file)
 549 {
 550         return single_open(file, lstats_show_proc, inode);
 551 }
 552
 553 static ssize_t lstats_write(struct file *file, const char __user *buf,
 554                             size_t count, loff_t *offs)
 555 {
 556         struct task_struct *task = get_proc_task(file_inode(file));
 557
 558         if (!task)
 559                 return -ESRCH;
 560         clear_all_latency_tracing(task);
 561         put_task_struct(task);
 562
 563         return count;
 564 }
 565
 566 static const struct file_operations proc_lstats_operations = {
 567         .open           = lstats_open,
 568         .read           = seq_read,
 569         .write          = lstats_write,
 570         .llseek         = seq_lseek,
 571         .release        = single_release,
 572 };
 573
 574 #endif
 575
 576 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
 577                           struct pid *pid, struct task_struct *task)
 578 {
 579         unsigned long totalpages = totalram_pages + total_swap_pages;
 580         unsigned long points = 0;
 581
 582         read_lock(&tasklist_lock);
 583         if (pid_alive(task))
 584                 points = oom_badness(task, NULL, NULL, totalpages) *
 585                                                 1000 / totalpages;
 586         read_unlock(&tasklist_lock);
 587         seq_printf(m, "%lu\n", points);
 588
 589         return 0;
 590 }
 591
 592 struct limit_names {
 593         const char *name;
 594         const char *unit;
 595 };
 596
 597 static const struct limit_names lnames[RLIM_NLIMITS] = {
 598         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
 599         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 600         [RLIMIT_DATA] = {"Max data size", "bytes"},
 601         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 602         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 603         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 604         [RLIMIT_NPROC] = {"Max processes", "processes"},
 605         [RLIMIT_NOFILE] = {"Max open files", "files"},
 606         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 607         [RLIMIT_AS] = {"Max address space", "bytes"},
 608         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 609         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 610         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 611         [RLIMIT_NICE] = {"Max nice priority", NULL},
 612         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 613         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 614 };
 615
 616 /* Display limits for a process */
 617 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 618                            struct pid *pid, struct task_struct *task)
 619 {
 620         unsigned int i;
 621         unsigned long flags;
 622
 623         struct rlimit rlim[RLIM_NLIMITS];
 624
 625         if (!lock_task_sighand(task, &flags))
 626                 return 0;
 627         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 628         unlock_task_sighand(task, &flags);
 629
 630         /*
 631          * print the file header
 632          */
 633        seq_printf(m, "%-25s %-20s %-20s %-10s\n",
 634                   "Limit", "Soft Limit", "Hard Limit", "Units");
 635
 636         for (i = 0; i < RLIM_NLIMITS; i++) {
 637                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 638                         seq_printf(m, "%-25s %-20s ",
 639                                    lnames[i].name, "unlimited");
 640                 else
 641                         seq_printf(m, "%-25s %-20lu ",
 642                                    lnames[i].name, rlim[i].rlim_cur);
 643
 644                 if (rlim[i].rlim_max == RLIM_INFINITY)
 645                         seq_printf(m, "%-20s ", "unlimited");
 646                 else
 647                         seq_printf(m, "%-20lu ", rlim[i].rlim_max);
 648
 649                 if (lnames[i].unit)
 650                         seq_printf(m, "%-10s\n", lnames[i].unit);
 651                 else
 652                         seq_putc(m, '\n');
 653         }
 654
 655         return 0;
 656 }
 657
 658 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 659 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 660                             struct pid *pid, struct task_struct *task)
 661 {
 662         long nr;
 663         unsigned long args[6], sp, pc;
 664         int res;
 665
 666         res = lock_trace(task);
 667         if (res)
 668                 return res;
 669
 670         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 671                 seq_puts(m, "running\n");
 672         else if (nr < 0)
 673                 seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 674         else
 675                 seq_printf(m,
 676                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 677                        nr,
 678                        args[0], args[1], args[2], args[3], args[4], args[5],
 679                        sp, pc);
 680         unlock_trace(task);
 681
 682         return 0;
 683 }
 684 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 685
 686 /************************************************************************/
 687 /*                       Here the fs part begins                        */
 688 /************************************************************************/
 689
 690 /* permission checks */
 691 static int proc_fd_access_allowed(struct inode *inode)
 692 {
 693         struct task_struct *task;
 694         int allowed = 0;
 695         /* Allow access to a task's file descriptors if it is us or we
 696          * may use ptrace attach to the process and find out that
 697          * information.
 698          */
 699         task = get_proc_task(inode);
 700         if (task) {
 701                 allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 702                 put_task_struct(task);
 703         }
 704         return allowed;
 705 }
 706
 707 int proc_setattr(struct dentry *dentry, struct iattr *attr)
 708 {
 709         int error;
 710         struct inode *inode = d_inode(dentry);
 711
 712         if (attr->ia_valid & ATTR_MODE)
 713                 return -EPERM;
 714
 715         error = inode_change_ok(inode, attr);
 716         if (error)
 717                 return error;
 718
 719         setattr_copy(inode, attr);
 720         mark_inode_dirty(inode);
 721         return 0;
 722 }
 723
 724 /*
 725  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
 726  * or euid/egid (for hide_pid_min=2)?
 727  */
 728 static bool has_pid_permissions(struct pid_namespace *pid,
 729                                  struct task_struct *task,
 730                                  int hide_pid_min)
 731 {
 732         if (pid->hide_pid < hide_pid_min)
 733                 return true;
 734         if (in_group_p(pid->pid_gid))
 735                 return true;
 736         return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 737 }
 738
 739
 740 static int proc_pid_permission(struct inode *inode, int mask)
 741 {
 742         struct pid_namespace *pid = inode->i_sb->s_fs_info;
 743         struct task_struct *task;
 744         bool has_perms;
 745
 746         task = get_proc_task(inode);
 747         if (!task)
 748                 return -ESRCH;
 749         has_perms = has_pid_permissions(pid, task, 1);
 750         put_task_struct(task);
 751
 752         if (!has_perms) {
 753                 if (pid->hide_pid == 2) {
 754                         /*
 755                          * Let's make getdents(), stat(), and open()
 756                          * consistent with each other.  If a process
 757                          * may not stat() a file, it shouldn't be seen
 758                          * in procfs at all.
 759                          */
 760                         return -ENOENT;
 761                 }
 762
 763                 return -EPERM;
 764         }
 765         return generic_permission(inode, mask);
 766 }
 767
 768
 769
 770 static const struct inode_operations proc_def_inode_operations = {
 771         .setattr        = proc_setattr,
 772 };
 773
 774 static int proc_single_show(struct seq_file *m, void *v)
 775 {
 776         struct inode *inode = m->private;
 777         struct pid_namespace *ns;
 778         struct pid *pid;
 779         struct task_struct *task;
 780         int ret;
 781
 782         ns = inode->i_sb->s_fs_info;
 783         pid = proc_pid(inode);
 784         task = get_pid_task(pid, PIDTYPE_PID);
 785         if (!task)
 786                 return -ESRCH;
 787
 788         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 789
 790         put_task_struct(task);
 791         return ret;
 792 }
 793
 794 static int proc_single_open(struct inode *inode, struct file *filp)
 795 {
 796         return single_open(filp, proc_single_show, inode);
 797 }
 798
 799 static const struct file_operations proc_single_file_operations = {
 800         .open           = proc_single_open,
 801         .read           = seq_read,
 802         .llseek         = seq_lseek,
 803         .release        = single_release,
 804 };
 805
 806
 807 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
 808 {
 809         struct task_struct *task = get_proc_task(inode);
 810         struct mm_struct *mm = ERR_PTR(-ESRCH);
 811
 812         if (task) {
 813                 mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
 814                 put_task_struct(task);
 815
 816                 if (!IS_ERR_OR_NULL(mm)) {
 817                         /* ensure this mm_struct can't be freed */
 818                         atomic_inc(&mm->mm_count);
 819                         /* but do not pin its memory */
 820                         mmput(mm);
 821                 }
 822         }
 823
 824         return mm;
 825 }
 826
 827 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
 828 {
 829         struct mm_struct *mm = proc_mem_open(inode, mode);
 830
 831         if (IS_ERR(mm))
 832                 return PTR_ERR(mm);
 833
 834         file->private_data = mm;
 835         return 0;
 836 }
 837
 838 static int mem_open(struct inode *inode, struct file *file)
 839 {
 840         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
 841
 842         /* OK to pass negative loff_t, we can catch out-of-range */
 843         file->f_mode |= FMODE_UNSIGNED_OFFSET;
 844
 845         return ret;
 846 }
 847
 848 static ssize_t mem_rw(struct file *file, char __user *buf,
 849                         size_t count, loff_t *ppos, int write)
 850 {
 851         struct mm_struct *mm = file->private_data;
 852         unsigned long addr = *ppos;
 853         ssize_t copied;
 854         char *page;
 855
 856         if (!mm)
 857                 return 0;
 858
 859         page = (char *)__get_free_page(GFP_TEMPORARY);
 860         if (!page)
 861                 return -ENOMEM;
 862
 863         copied = 0;
 864         if (!atomic_inc_not_zero(&mm->mm_users))
 865                 goto free;
 866
 867         while (count > 0) {
 868                 int this_len = min_t(int, count, PAGE_SIZE);
 869
 870                 if (write && copy_from_user(page, buf, this_len)) {
 871                         copied = -EFAULT;
 872                         break;
 873                 }
 874
 875                 this_len = access_remote_vm(mm, addr, page, this_len, write);
 876                 if (!this_len) {
 877                         if (!copied)
 878                                 copied = -EIO;
 879                         break;
 880                 }
 881
 882                 if (!write && copy_to_user(buf, page, this_len)) {
 883                         copied = -EFAULT;
 884                         break;
 885                 }
 886
 887                 buf += this_len;
 888                 addr += this_len;
 889                 copied += this_len;
 890                 count -= this_len;
 891         }
 892         *ppos = addr;
 893
 894         mmput(mm);
 895 free:
 896         free_page((unsigned long) page);
 897         return copied;
 898 }
 899
 900 static ssize_t mem_read(struct file *file, char __user *buf,
 901                         size_t count, loff_t *ppos)
 902 {
 903         return mem_rw(file, buf, count, ppos, 0);
 904 }
 905
 906 static ssize_t mem_write(struct file *file, const char __user *buf,
 907                          size_t count, loff_t *ppos)
 908 {
 909         return mem_rw(file, (char __user*)buf, count, ppos, 1);
 910 }
 911
 912 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 913 {
 914         switch (orig) {
 915         case 0:
 916                 file->f_pos = offset;
 917                 break;
 918         case 1:
 919                 file->f_pos += offset;
 920                 break;
 921         default:
 922                 return -EINVAL;
 923         }
 924         force_successful_syscall_return();
 925         return file->f_pos;
 926 }
 927
 928 static int mem_release(struct inode *inode, struct file *file)
 929 {
 930         struct mm_struct *mm = file->private_data;
 931         if (mm)
 932                 mmdrop(mm);
 933         return 0;
 934 }
 935
 936 static const struct file_operations proc_mem_operations = {
 937         .llseek         = mem_lseek,
 938         .read           = mem_read,
 939         .write          = mem_write,
 940         .open           = mem_open,
 941         .release        = mem_release,
 942 };
 943
 944 static int environ_open(struct inode *inode, struct file *file)
 945 {
 946         return __mem_open(inode, file, PTRACE_MODE_READ);
 947 }
 948
 949 static ssize_t environ_read(struct file *file, char __user *buf,
 950                         size_t count, loff_t *ppos)
 951 {
 952         char *page;
 953         unsigned long src = *ppos;
 954         int ret = 0;
 955         struct mm_struct *mm = file->private_data;
 956         unsigned long env_start, env_end;
 957
 958         if (!mm)
 959                 return 0;
 960
 961         page = (char *)__get_free_page(GFP_TEMPORARY);
 962         if (!page)
 963                 return -ENOMEM;
 964
 965         ret = 0;
 966         if (!atomic_inc_not_zero(&mm->mm_users))
 967                 goto free;
 968
 969         down_read(&mm->mmap_sem);
 970         env_start = mm->env_start;
 971         env_end = mm->env_end;
 972         up_read(&mm->mmap_sem);
 973
 974         while (count > 0) {
 975                 size_t this_len, max_len;
 976                 int retval;
 977
 978                 if (src >= (env_end - env_start))
 979                         break;
 980
 981                 this_len = env_end - (env_start + src);
 982
 983                 max_len = min_t(size_t, PAGE_SIZE, count);
 984                 this_len = min(max_len, this_len);
 985
 986                 retval = access_remote_vm(mm, (env_start + src),
 987                         page, this_len, 0);
 988
 989                 if (retval <= 0) {
 990                         ret = retval;
 991                         break;
 992                 }
 993
 994                 if (copy_to_user(buf, page, retval)) {
 995                         ret = -EFAULT;
 996                         break;
 997                 }
 998
 999                 ret += retval;
1000                 src += retval;
1001                 buf += retval;
1002                 count -= retval;
1003         }
1004         *ppos = src;
1005         mmput(mm);
1006
1007 free:
1008         free_page((unsigned long) page);
1009         return ret;
1010 }
1011
1012 static const struct file_operations proc_environ_operations = {
1013         .open           = environ_open,
1014         .read           = environ_read,
1015         .llseek         = generic_file_llseek,
1016         .release        = mem_release,
1017 };
1018
1019 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1020                             loff_t *ppos)
1021 {
1022         struct task_struct *task = get_proc_task(file_inode(file));
1023         char buffer[PROC_NUMBUF];
1024         int oom_adj = OOM_ADJUST_MIN;
1025         size_t len;
1026         unsigned long flags;
1027
1028         if (!task)
1029                 return -ESRCH;
1030         if (lock_task_sighand(task, &flags)) {
1031                 if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1032                         oom_adj = OOM_ADJUST_MAX;
1033                 else
1034                         oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1035                                   OOM_SCORE_ADJ_MAX;
1036                 unlock_task_sighand(task, &flags);
1037         }
1038         put_task_struct(task);
1039         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1040         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1041 }
1042
1043 /*
1044  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1045  * kernels.  The effective policy is defined by oom_score_adj, which has a
1046  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1047  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1048  * Processes that become oom disabled via oom_adj will still be oom disabled
1049  * with this implementation.
1050  *
1051  * oom_adj cannot be removed since existing userspace binaries use it.
1052  */
1053 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1054                              size_t count, loff_t *ppos)
1055 {
1056         struct task_struct *task;
1057         char buffer[PROC_NUMBUF];
1058         int oom_adj;
1059         unsigned long flags;
1060         int err;
1061
1062         memset(buffer, 0, sizeof(buffer));
1063         if (count > sizeof(buffer) - 1)
1064                 count = sizeof(buffer) - 1;
1065         if (copy_from_user(buffer, buf, count)) {
1066                 err = -EFAULT;
1067                 goto out;
1068         }
1069
1070         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1071         if (err)
1072                 goto out;
1073         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1074              oom_adj != OOM_DISABLE) {
1075                 err = -EINVAL;
1076                 goto out;
1077         }
1078
1079         task = get_proc_task(file_inode(file));
1080         if (!task) {
1081                 err = -ESRCH;
1082                 goto out;
1083         }
1084
1085         task_lock(task);
1086         if (!task->mm) {
1087                 err = -EINVAL;
1088                 goto err_task_lock;
1089         }
1090
1091         if (!lock_task_sighand(task, &flags)) {
1092                 err = -ESRCH;
1093                 goto err_task_lock;
1094         }
1095
1096         /*
1097          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1098          * value is always attainable.
1099          */
1100         if (oom_adj == OOM_ADJUST_MAX)
1101                 oom_adj = OOM_SCORE_ADJ_MAX;
1102         else
1103                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1104
1105         if (oom_adj < task->signal->oom_score_adj &&
1106             !capable(CAP_SYS_RESOURCE)) {
1107                 err = -EACCES;
1108                 goto err_sighand;
1109         }
1110
1111         /*
1112          * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1113          * /proc/pid/oom_score_adj instead.
1114          */
1115         pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1116                   current->comm, task_pid_nr(current), task_pid_nr(task),
1117                   task_pid_nr(task));
1118
1119         task->signal->oom_score_adj = oom_adj;
1120         trace_oom_score_adj_update(task);
1121 err_sighand:
1122         unlock_task_sighand(task, &flags);
1123 err_task_lock:
1124         task_unlock(task);
1125         put_task_struct(task);
1126 out:
1127         return err < 0 ? err : count;
1128 }
1129
1130 static const struct file_operations proc_oom_adj_operations = {
1131         .read           = oom_adj_read,
1132         .write          = oom_adj_write,
1133         .llseek         = generic_file_llseek,
1134 };
1135
1136 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1137                                         size_t count, loff_t *ppos)
1138 {
1139         struct task_struct *task = get_proc_task(file_inode(file));
1140         char buffer[PROC_NUMBUF];
1141         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1142         unsigned long flags;
1143         size_t len;
1144
1145         if (!task)
1146                 return -ESRCH;
1147         if (lock_task_sighand(task, &flags)) {
1148                 oom_score_adj = task->signal->oom_score_adj;
1149                 unlock_task_sighand(task, &flags);
1150         }
1151         put_task_struct(task);
1152         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1153         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1154 }
1155
1156 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1157                                         size_t count, loff_t *ppos)
1158 {
1159         struct task_struct *task;
1160         char buffer[PROC_NUMBUF];
1161         unsigned long flags;
1162         int oom_score_adj;
1163         int err;
1164
1165         memset(buffer, 0, sizeof(buffer));
1166         if (count > sizeof(buffer) - 1)
1167                 count = sizeof(buffer) - 1;
1168         if (copy_from_user(buffer, buf, count)) {
1169                 err = -EFAULT;
1170                 goto out;
1171         }
1172
1173         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1174         if (err)
1175                 goto out;
1176         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1177                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1178                 err = -EINVAL;
1179                 goto out;
1180         }
1181
1182         task = get_proc_task(file_inode(file));
1183         if (!task) {
1184                 err = -ESRCH;
1185                 goto out;
1186         }
1187
1188         task_lock(task);
1189         if (!task->mm) {
1190                 err = -EINVAL;
1191                 goto err_task_lock;
1192         }
1193
1194         if (!lock_task_sighand(task, &flags)) {
1195                 err = -ESRCH;
1196                 goto err_task_lock;
1197         }
1198
1199         if ((short)oom_score_adj < task->signal->oom_score_adj_min &&
1200                         !capable(CAP_SYS_RESOURCE)) {
1201                 err = -EACCES;
1202                 goto err_sighand;
1203         }
1204
1205         task->signal->oom_score_adj = (short)oom_score_adj;
1206         if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1207                 task->signal->oom_score_adj_min = (short)oom_score_adj;
1208         trace_oom_score_adj_update(task);
1209
1210 err_sighand:
1211         unlock_task_sighand(task, &flags);
1212 err_task_lock:
1213         task_unlock(task);
1214         put_task_struct(task);
1215 out:
1216         return err < 0 ? err : count;
1217 }
1218
1219 static const struct file_operations proc_oom_score_adj_operations = {
1220         .read           = oom_score_adj_read,
1221         .write          = oom_score_adj_write,
1222         .llseek         = default_llseek,
1223 };
1224
1225 #ifdef CONFIG_AUDITSYSCALL
1226 #define TMPBUFLEN 21
1227 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1228                                   size_t count, loff_t *ppos)
1229 {
1230         struct inode * inode = file_inode(file);
1231         struct task_struct *task = get_proc_task(inode);
1232         ssize_t length;
1233         char tmpbuf[TMPBUFLEN];
1234
1235         if (!task)
1236                 return -ESRCH;
1237         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1238                            from_kuid(file->f_cred->user_ns,
1239                                      audit_get_loginuid(task)));
1240         put_task_struct(task);
1241         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1242 }
1243
1244 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1245                                    size_t count, loff_t *ppos)
1246 {
1247         struct inode * inode = file_inode(file);
1248         uid_t loginuid;
1249         kuid_t kloginuid;
1250         int rv;
1251
1252         rcu_read_lock();
1253         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1254                 rcu_read_unlock();
1255                 return -EPERM;
1256         }
1257         rcu_read_unlock();
1258
1259         if (*ppos != 0) {
1260                 /* No partial writes. */
1261                 return -EINVAL;
1262         }
1263
1264         rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1265         if (rv < 0)
1266                 return rv;
1267
1268         /* is userspace tring to explicitly UNSET the loginuid? */
1269         if (loginuid == AUDIT_UID_UNSET) {
1270                 kloginuid = INVALID_UID;
1271         } else {
1272                 kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1273                 if (!uid_valid(kloginuid))
1274                         return -EINVAL;
1275         }
1276
1277         rv = audit_set_loginuid(kloginuid);
1278         if (rv < 0)
1279                 return rv;
1280         return count;
1281 }
1282
1283 static const struct file_operations proc_loginuid_operations = {
1284         .read           = proc_loginuid_read,
1285         .write          = proc_loginuid_write,
1286         .llseek         = generic_file_llseek,
1287 };
1288
1289 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1290                                   size_t count, loff_t *ppos)
1291 {
1292         struct inode * inode = file_inode(file);
1293         struct task_struct *task = get_proc_task(inode);
1294         ssize_t length;
1295         char tmpbuf[TMPBUFLEN];
1296
1297         if (!task)
1298                 return -ESRCH;
1299         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1300                                 audit_get_sessionid(task));
1301         put_task_struct(task);
1302         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1303 }
1304
1305 static const struct file_operations proc_sessionid_operations = {
1306         .read           = proc_sessionid_read,
1307         .llseek         = generic_file_llseek,
1308 };
1309 #endif
1310
1311 #ifdef CONFIG_FAULT_INJECTION
1312 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1313                                       size_t count, loff_t *ppos)
1314 {
1315         struct task_struct *task = get_proc_task(file_inode(file));
1316         char buffer[PROC_NUMBUF];
1317         size_t len;
1318         int make_it_fail;
1319
1320         if (!task)
1321                 return -ESRCH;
1322         make_it_fail = task->make_it_fail;
1323         put_task_struct(task);
1324
1325         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1326
1327         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1328 }
1329
1330 static ssize_t proc_fault_inject_write(struct file * file,
1331                         const char __user * buf, size_t count, loff_t *ppos)
1332 {
1333         struct task_struct *task;
1334         char buffer[PROC_NUMBUF];
1335         int make_it_fail;
1336         int rv;
1337
1338         if (!capable(CAP_SYS_RESOURCE))
1339                 return -EPERM;
1340         memset(buffer, 0, sizeof(buffer));
1341         if (count > sizeof(buffer) - 1)
1342                 count = sizeof(buffer) - 1;
1343         if (copy_from_user(buffer, buf, count))
1344                 return -EFAULT;
1345         rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1346         if (rv < 0)
1347                 return rv;
1348         if (make_it_fail < 0 || make_it_fail > 1)
1349                 return -EINVAL;
1350
1351         task = get_proc_task(file_inode(file));
1352         if (!task)
1353                 return -ESRCH;
1354         task->make_it_fail = make_it_fail;
1355         put_task_struct(task);
1356
1357         return count;
1358 }
1359
1360 static const struct file_operations proc_fault_inject_operations = {
1361         .read           = proc_fault_inject_read,
1362         .write          = proc_fault_inject_write,
1363         .llseek         = generic_file_llseek,
1364 };
1365 #endif
1366
1367
1368 #ifdef CONFIG_SCHED_DEBUG
1369 /*
1370  * Print out various scheduling related per-task fields:
1371  */
1372 static int sched_show(struct seq_file *m, void *v)
1373 {
1374         struct inode *inode = m->private;
1375         struct task_struct *p;
1376
1377         p = get_proc_task(inode);
1378         if (!p)
1379                 return -ESRCH;
1380         proc_sched_show_task(p, m);
1381
1382         put_task_struct(p);
1383
1384         return 0;
1385 }
1386
1387 static ssize_t
1388 sched_write(struct file *file, const char __user *buf,
1389             size_t count, loff_t *offset)
1390 {
1391         struct inode *inode = file_inode(file);
1392         struct task_struct *p;
1393
1394         p = get_proc_task(inode);
1395         if (!p)
1396                 return -ESRCH;
1397         proc_sched_set_task(p);
1398
1399         put_task_struct(p);
1400
1401         return count;
1402 }
1403
1404 static int sched_open(struct inode *inode, struct file *filp)
1405 {
1406         return single_open(filp, sched_show, inode);
1407 }
1408
1409 static const struct file_operations proc_pid_sched_operations = {
1410         .open           = sched_open,
1411         .read           = seq_read,
1412         .write          = sched_write,
1413         .llseek         = seq_lseek,
1414         .release        = single_release,
1415 };
1416
1417 #endif
1418
1419 #ifdef CONFIG_SCHED_AUTOGROUP
1420 /*
1421  * Print out autogroup related information:
1422  */
1423 static int sched_autogroup_show(struct seq_file *m, void *v)
1424 {
1425         struct inode *inode = m->private;
1426         struct task_struct *p;
1427
1428         p = get_proc_task(inode);
1429         if (!p)
1430                 return -ESRCH;
1431         proc_sched_autogroup_show_task(p, m);
1432
1433         put_task_struct(p);
1434
1435         return 0;
1436 }
1437
1438 static ssize_t
1439 sched_autogroup_write(struct file *file, const char __user *buf,
1440             size_t count, loff_t *offset)
1441 {
1442         struct inode *inode = file_inode(file);
1443         struct task_struct *p;
1444         char buffer[PROC_NUMBUF];
1445         int nice;
1446         int err;
1447
1448         memset(buffer, 0, sizeof(buffer));
1449         if (count > sizeof(buffer) - 1)
1450                 count = sizeof(buffer) - 1;
1451         if (copy_from_user(buffer, buf, count))
1452                 return -EFAULT;
1453
1454         err = kstrtoint(strstrip(buffer), 0, &nice);
1455         if (err < 0)
1456                 return err;
1457
1458         p = get_proc_task(inode);
1459         if (!p)
1460                 return -ESRCH;
1461
1462         err = proc_sched_autogroup_set_nice(p, nice);
1463         if (err)
1464                 count = err;
1465
1466         put_task_struct(p);
1467
1468         return count;
1469 }
1470
1471 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1472 {
1473         int ret;
1474
1475         ret = single_open(filp, sched_autogroup_show, NULL);
1476         if (!ret) {
1477                 struct seq_file *m = filp->private_data;
1478
1479                 m->private = inode;
1480         }
1481         return ret;
1482 }
1483
1484 static const struct file_operations proc_pid_sched_autogroup_operations = {
1485         .open           = sched_autogroup_open,
1486         .read           = seq_read,
1487         .write          = sched_autogroup_write,
1488         .llseek         = seq_lseek,
1489         .release        = single_release,
1490 };
1491
1492 #endif /* CONFIG_SCHED_AUTOGROUP */
1493
1494 static ssize_t comm_write(struct file *file, const char __user *buf,
1495                                 size_t count, loff_t *offset)
1496 {
1497         struct inode *inode = file_inode(file);
1498         struct task_struct *p;
1499         char buffer[TASK_COMM_LEN];
1500         const size_t maxlen = sizeof(buffer) - 1;
1501
1502         memset(buffer, 0, sizeof(buffer));
1503         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1504                 return -EFAULT;
1505
1506         p = get_proc_task(inode);
1507         if (!p)
1508                 return -ESRCH;
1509
1510         if (same_thread_group(current, p))
1511                 set_task_comm(p, buffer);
1512         else
1513                 count = -EINVAL;
1514
1515         put_task_struct(p);
1516
1517         return count;
1518 }
1519
1520 static int comm_show(struct seq_file *m, void *v)
1521 {
1522         struct inode *inode = m->private;
1523         struct task_struct *p;
1524
1525         p = get_proc_task(inode);
1526         if (!p)
1527                 return -ESRCH;
1528
1529         task_lock(p);
1530         seq_printf(m, "%s\n", p->comm);
1531         task_unlock(p);
1532
1533         put_task_struct(p);
1534
1535         return 0;
1536 }
1537
1538 static int comm_open(struct inode *inode, struct file *filp)
1539 {
1540         return single_open(filp, comm_show, inode);
1541 }
1542
1543 static const struct file_operations proc_pid_set_comm_operations = {
1544         .open           = comm_open,
1545         .read           = seq_read,
1546         .write          = comm_write,
1547         .llseek         = seq_lseek,
1548         .release        = single_release,
1549 };
1550
1551 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1552 {
1553         struct task_struct *task;
1554         struct mm_struct *mm;
1555         struct file *exe_file;
1556
1557         task = get_proc_task(d_inode(dentry));
1558         if (!task)
1559                 return -ENOENT;
1560         mm = get_task_mm(task);
1561         put_task_struct(task);
1562         if (!mm)
1563                 return -ENOENT;
1564         exe_file = get_mm_exe_file(mm);
1565         mmput(mm);
1566         if (exe_file) {
1567                 *exe_path = exe_file->f_path;
1568                 path_get(&exe_file->f_path);
1569                 fput(exe_file);
1570                 return 0;
1571         } else
1572                 return -ENOENT;
1573 }
1574
1575 static const char *proc_pid_get_link(struct dentry *dentry,
1576                                      struct inode *inode,
1577                                      struct delayed_call *done)
1578 {
1579         struct path path;
1580         int error = -EACCES;
1581
1582         if (!dentry)
1583                 return ERR_PTR(-ECHILD);
1584
1585         /* Are we allowed to snoop on the tasks file descriptors? */
1586         if (!proc_fd_access_allowed(inode))
1587                 goto out;
1588
1589         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1590         if (error)
1591                 goto out;
1592
1593         nd_jump_link(&path);
1594         return NULL;
1595 out:
1596         return ERR_PTR(error);
1597 }
1598
1599 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1600 {
1601         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1602         char *pathname;
1603         int len;
1604
1605         if (!tmp)
1606                 return -ENOMEM;
1607
1608         pathname = d_path(path, tmp, PAGE_SIZE);
1609         len = PTR_ERR(pathname);
1610         if (IS_ERR(pathname))
1611                 goto out;
1612         len = tmp + PAGE_SIZE - 1 - pathname;
1613
1614         if (len > buflen)
1615                 len = buflen;
1616         if (copy_to_user(buffer, pathname, len))
1617                 len = -EFAULT;
1618  out:
1619         free_page((unsigned long)tmp);
1620         return len;
1621 }
1622
1623 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1624 {
1625         int error = -EACCES;
1626         struct inode *inode = d_inode(dentry);
1627         struct path path;
1628
1629         /* Are we allowed to snoop on the tasks file descriptors? */
1630         if (!proc_fd_access_allowed(inode))
1631                 goto out;
1632
1633         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1634         if (error)
1635                 goto out;
1636
1637         error = do_proc_readlink(&path, buffer, buflen);
1638         path_put(&path);
1639 out:
1640         return error;
1641 }
1642
1643 const struct inode_operations proc_pid_link_inode_operations = {
1644         .readlink       = proc_pid_readlink,
1645         .get_link       = proc_pid_get_link,
1646         .setattr        = proc_setattr,
1647 };
1648
1649
1650 /* building an inode */
1651
1652 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1653 {
1654         struct inode * inode;
1655         struct proc_inode *ei;
1656         const struct cred *cred;
1657
1658         /* We need a new inode */
1659
1660         inode = new_inode(sb);
1661         if (!inode)
1662                 goto out;
1663
1664         /* Common stuff */
1665         ei = PROC_I(inode);
1666         inode->i_ino = get_next_ino();
1667         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1668         inode->i_op = &proc_def_inode_operations;
1669
1670         /*
1671          * grab the reference to task.
1672          */
1673         ei->pid = get_task_pid(task, PIDTYPE_PID);
1674         if (!ei->pid)
1675                 goto out_unlock;
1676
1677         if (task_dumpable(task)) {
1678                 rcu_read_lock();
1679                 cred = __task_cred(task);
1680                 inode->i_uid = cred->euid;
1681                 inode->i_gid = cred->egid;
1682                 rcu_read_unlock();
1683         }
1684         security_task_to_inode(task, inode);
1685
1686 out:
1687         return inode;
1688
1689 out_unlock:
1690         iput(inode);
1691         return NULL;
1692 }
1693
1694 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1695 {
1696         struct inode *inode = d_inode(dentry);
1697         struct task_struct *task;
1698         const struct cred *cred;
1699         struct pid_namespace *pid = dentry->d_sb->s_fs_info;
1700
1701         generic_fillattr(inode, stat);
1702
1703         rcu_read_lock();
1704         stat->uid = GLOBAL_ROOT_UID;
1705         stat->gid = GLOBAL_ROOT_GID;
1706         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1707         if (task) {
1708                 if (!has_pid_permissions(pid, task, 2)) {
1709                         rcu_read_unlock();
1710                         /*
1711                          * This doesn't prevent learning whether PID exists,
1712                          * it only makes getattr() consistent with readdir().
1713                          */
1714                         return -ENOENT;
1715                 }
1716                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1717                     task_dumpable(task)) {
1718                         cred = __task_cred(task);
1719                         stat->uid = cred->euid;
1720                         stat->gid = cred->egid;
1721                 }
1722         }
1723         rcu_read_unlock();
1724         return 0;
1725 }
1726
1727 /* dentry stuff */
1728
1729 /*
1730  *      Exceptional case: normally we are not allowed to unhash a busy
1731  * directory. In this case, however, we can do it - no aliasing problems
1732  * due to the way we treat inodes.
1733  *
1734  * Rewrite the inode's ownerships here because the owning task may have
1735  * performed a setuid(), etc.
1736  *
1737  * Before the /proc/pid/status file was created the only way to read
1738  * the effective uid of a /process was to stat /proc/pid.  Reading
1739  * /proc/pid/status is slow enough that procps and other packages
1740  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1741  * made this apply to all per process world readable and executable
1742  * directories.
1743  */
1744 int pid_revalidate(struct dentry *dentry, unsigned int flags)
1745 {
1746         struct inode *inode;
1747         struct task_struct *task;
1748         const struct cred *cred;
1749
1750         if (flags & LOOKUP_RCU)
1751                 return -ECHILD;
1752
1753         inode = d_inode(dentry);
1754         task = get_proc_task(inode);
1755
1756         if (task) {
1757                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1758                     task_dumpable(task)) {
1759                         rcu_read_lock();
1760                         cred = __task_cred(task);
1761                         inode->i_uid = cred->euid;
1762                         inode->i_gid = cred->egid;
1763                         rcu_read_unlock();
1764                 } else {
1765                         inode->i_uid = GLOBAL_ROOT_UID;
1766                         inode->i_gid = GLOBAL_ROOT_GID;
1767                 }
1768                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1769                 security_task_to_inode(task, inode);
1770                 put_task_struct(task);
1771                 return 1;
1772         }
1773         return 0;
1774 }
1775
1776 static inline bool proc_inode_is_dead(struct inode *inode)
1777 {
1778         return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1779 }
1780
1781 int pid_delete_dentry(const struct dentry *dentry)
1782 {
1783         /* Is the task we represent dead?
1784          * If so, then don't put the dentry on the lru list,
1785          * kill it immediately.
1786          */
1787         return proc_inode_is_dead(d_inode(dentry));
1788 }
1789
1790 const struct dentry_operations pid_dentry_operations =
1791 {
1792         .d_revalidate   = pid_revalidate,
1793         .d_delete       = pid_delete_dentry,
1794 };
1795
1796 /* Lookups */
1797
1798 /*
1799  * Fill a directory entry.
1800  *
1801  * If possible create the dcache entry and derive our inode number and
1802  * file type from dcache entry.
1803  *
1804  * Since all of the proc inode numbers are dynamically generated, the inode
1805  * numbers do not exist until the inode is cache.  This means creating the
1806  * the dcache entry in readdir is necessary to keep the inode numbers
1807  * reported by readdir in sync with the inode numbers reported
1808  * by stat.
1809  */
1810 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1811         const char *name, int len,
1812         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1813 {
1814         struct dentry *child, *dir = file->f_path.dentry;
1815         struct qstr qname = QSTR_INIT(name, len);
1816         struct inode *inode;
1817         unsigned type;
1818         ino_t ino;
1819
1820         child = d_hash_and_lookup(dir, &qname);
1821         if (!child) {
1822                 child = d_alloc(dir, &qname);
1823                 if (!child)
1824                         goto end_instantiate;
1825                 if (instantiate(d_inode(dir), child, task, ptr) < 0) {
1826                         dput(child);
1827                         goto end_instantiate;
1828                 }
1829         }
1830         inode = d_inode(child);
1831         ino = inode->i_ino;
1832         type = inode->i_mode >> 12;
1833         dput(child);
1834         return dir_emit(ctx, name, len, ino, type);
1835
1836 end_instantiate:
1837         return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
1838 }
1839
1840 /*
1841  * dname_to_vma_addr - maps a dentry name into two unsigned longs
1842  * which represent vma start and end addresses.
1843  */
1844 static int dname_to_vma_addr(struct dentry *dentry,
1845                              unsigned long *start, unsigned long *end)
1846 {
1847         if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
1848                 return -EINVAL;
1849
1850         return 0;
1851 }
1852
1853 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1854 {
1855         unsigned long vm_start, vm_end;
1856         bool exact_vma_exists = false;
1857         struct mm_struct *mm = NULL;
1858         struct task_struct *task;
1859         const struct cred *cred;
1860         struct inode *inode;
1861         int status = 0;
1862
1863         if (flags & LOOKUP_RCU)
1864                 return -ECHILD;
1865
1866         inode = d_inode(dentry);
1867         task = get_proc_task(inode);
1868         if (!task)
1869                 goto out_notask;
1870
1871         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1872         if (IS_ERR_OR_NULL(mm))
1873                 goto out;
1874
1875         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1876                 down_read(&mm->mmap_sem);
1877                 exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1878                 up_read(&mm->mmap_sem);
1879         }
1880
1881         mmput(mm);
1882
1883         if (exact_vma_exists) {
1884                 if (task_dumpable(task)) {
1885                         rcu_read_lock();
1886                         cred = __task_cred(task);
1887                         inode->i_uid = cred->euid;
1888                         inode->i_gid = cred->egid;
1889                         rcu_read_unlock();
1890                 } else {
1891                         inode->i_uid = GLOBAL_ROOT_UID;
1892                         inode->i_gid = GLOBAL_ROOT_GID;
1893                 }
1894                 security_task_to_inode(task, inode);
1895                 status = 1;
1896         }
1897
1898 out:
1899         put_task_struct(task);
1900
1901 out_notask:
1902         return status;
1903 }
1904
1905 static const struct dentry_operations tid_map_files_dentry_operations = {
1906         .d_revalidate   = map_files_d_revalidate,
1907         .d_delete       = pid_delete_dentry,
1908 };
1909
1910 static int map_files_get_link(struct dentry *dentry, struct path *path)
1911 {
1912         unsigned long vm_start, vm_end;
1913         struct vm_area_struct *vma;
1914         struct task_struct *task;
1915         struct mm_struct *mm;
1916         int rc;
1917
1918         rc = -ENOENT;
1919         task = get_proc_task(d_inode(dentry));
1920         if (!task)
1921                 goto out;
1922
1923         mm = get_task_mm(task);
1924         put_task_struct(task);
1925         if (!mm)
1926                 goto out;
1927
1928         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
1929         if (rc)
1930                 goto out_mmput;
1931
1932         rc = -ENOENT;
1933         down_read(&mm->mmap_sem);
1934         vma = find_exact_vma(mm, vm_start, vm_end);
1935         if (vma && vma->vm_file) {
1936                 *path = vma->vm_file->f_path;
1937                 path_get(path);
1938                 rc = 0;
1939         }
1940         up_read(&mm->mmap_sem);
1941
1942 out_mmput:
1943         mmput(mm);
1944 out:
1945         return rc;
1946 }
1947
1948 struct map_files_info {
1949         fmode_t         mode;
1950         unsigned long   len;
1951         unsigned char   name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
1952 };
1953
1954 /*
1955  * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
1956  * symlinks may be used to bypass permissions on ancestor directories in the
1957  * path to the file in question.
1958  */
1959 static const char *
1960 proc_map_files_get_link(struct dentry *dentry,
1961                         struct inode *inode,
1962                         struct delayed_call *done)
1963 {
1964         if (!capable(CAP_SYS_ADMIN))
1965                 return ERR_PTR(-EPERM);
1966
1967         return proc_pid_get_link(dentry, inode, done);
1968 }
1969
1970 /*
1971  * Identical to proc_pid_link_inode_operations except for get_link()
1972  */
1973 static const struct inode_operations proc_map_files_link_inode_operations = {
1974         .readlink       = proc_pid_readlink,
1975         .get_link       = proc_map_files_get_link,
1976         .setattr        = proc_setattr,
1977 };
1978
1979 static int
1980 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
1981                            struct task_struct *task, const void *ptr)
1982 {
1983         fmode_t mode = (fmode_t)(unsigned long)ptr;
1984         struct proc_inode *ei;
1985         struct inode *inode;
1986
1987         inode = proc_pid_make_inode(dir->i_sb, task);
1988         if (!inode)
1989                 return -ENOENT;
1990
1991         ei = PROC_I(inode);
1992         ei->op.proc_get_link = map_files_get_link;
1993
1994         inode->i_op = &proc_map_files_link_inode_operations;
1995         inode->i_size = 64;
1996         inode->i_mode = S_IFLNK;
1997
1998         if (mode & FMODE_READ)
1999                 inode->i_mode |= S_IRUSR;
2000         if (mode & FMODE_WRITE)
2001                 inode->i_mode |= S_IWUSR;
2002
2003         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2004         d_add(dentry, inode);
2005
2006         return 0;
2007 }
2008
2009 static struct dentry *proc_map_files_lookup(struct inode *dir,
2010                 struct dentry *dentry, unsigned int flags)
2011 {
2012         unsigned long vm_start, vm_end;
2013         struct vm_area_struct *vma;
2014         struct task_struct *task;
2015         int result;
2016         struct mm_struct *mm;
2017
2018         result = -ENOENT;
2019         task = get_proc_task(dir);
2020         if (!task)
2021                 goto out;
2022
2023         result = -EACCES;
2024         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2025                 goto out_put_task;
2026
2027         result = -ENOENT;
2028         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2029                 goto out_put_task;
2030
2031         mm = get_task_mm(task);
2032         if (!mm)
2033                 goto out_put_task;
2034
2035         down_read(&mm->mmap_sem);
2036         vma = find_exact_vma(mm, vm_start, vm_end);
2037         if (!vma)
2038                 goto out_no_vma;
2039
2040         if (vma->vm_file)
2041                 result = proc_map_files_instantiate(dir, dentry, task,
2042                                 (void *)(unsigned long)vma->vm_file->f_mode);
2043
2044 out_no_vma:
2045         up_read(&mm->mmap_sem);
2046         mmput(mm);
2047 out_put_task:
2048         put_task_struct(task);
2049 out:
2050         return ERR_PTR(result);
2051 }
2052
2053 static const struct inode_operations proc_map_files_inode_operations = {
2054         .lookup         = proc_map_files_lookup,
2055         .permission     = proc_fd_permission,
2056         .setattr        = proc_setattr,
2057 };
2058
2059 static int
2060 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2061 {
2062         struct vm_area_struct *vma;
2063         struct task_struct *task;
2064         struct mm_struct *mm;
2065         unsigned long nr_files, pos, i;
2066         struct flex_array *fa = NULL;
2067         struct map_files_info info;
2068         struct map_files_info *p;
2069         int ret;
2070
2071         ret = -ENOENT;
2072         task = get_proc_task(file_inode(file));
2073         if (!task)
2074                 goto out;
2075
2076         ret = -EACCES;
2077         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2078                 goto out_put_task;
2079
2080         ret = 0;
2081         if (!dir_emit_dots(file, ctx))
2082                 goto out_put_task;
2083
2084         mm = get_task_mm(task);
2085         if (!mm)
2086                 goto out_put_task;
2087         down_read(&mm->mmap_sem);
2088
2089         nr_files = 0;
2090
2091         /*
2092          * We need two passes here:
2093          *
2094          *  1) Collect vmas of mapped files with mmap_sem taken
2095          *  2) Release mmap_sem and instantiate entries
2096          *
2097          * otherwise we get lockdep complained, since filldir()
2098          * routine might require mmap_sem taken in might_fault().
2099          */
2100
2101         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2102                 if (vma->vm_file && ++pos > ctx->pos)
2103                         nr_files++;
2104         }
2105
2106         if (nr_files) {
2107                 fa = flex_array_alloc(sizeof(info), nr_files,
2108                                         GFP_KERNEL);
2109                 if (!fa || flex_array_prealloc(fa, 0, nr_files,
2110                                                 GFP_KERNEL)) {
2111                         ret = -ENOMEM;
2112                         if (fa)
2113                                 flex_array_free(fa);
2114                         up_read(&mm->mmap_sem);
2115                         mmput(mm);
2116                         goto out_put_task;
2117                 }
2118                 for (i = 0, vma = mm->mmap, pos = 2; vma;
2119                                 vma = vma->vm_next) {
2120                         if (!vma->vm_file)
2121                                 continue;
2122                         if (++pos <= ctx->pos)
2123                                 continue;
2124
2125                         info.mode = vma->vm_file->f_mode;
2126                         info.len = snprintf(info.name,
2127                                         sizeof(info.name), "%lx-%lx",
2128                                         vma->vm_start, vma->vm_end);
2129                         if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2130                                 BUG();
2131                 }
2132         }
2133         up_read(&mm->mmap_sem);
2134
2135         for (i = 0; i < nr_files; i++) {
2136                 p = flex_array_get(fa, i);
2137                 if (!proc_fill_cache(file, ctx,
2138                                       p->name, p->len,
2139                                       proc_map_files_instantiate,
2140                                       task,
2141                                       (void *)(unsigned long)p->mode))
2142                         break;
2143                 ctx->pos++;
2144         }
2145         if (fa)
2146                 flex_array_free(fa);
2147         mmput(mm);
2148
2149 out_put_task:
2150         put_task_struct(task);
2151 out:
2152         return ret;
2153 }
2154
2155 static const struct file_operations proc_map_files_operations = {
2156         .read           = generic_read_dir,
2157         .iterate        = proc_map_files_readdir,
2158         .llseek         = default_llseek,
2159 };
2160
2161 struct timers_private {
2162         struct pid *pid;
2163         struct task_struct *task;
2164         struct sighand_struct *sighand;
2165         struct pid_namespace *ns;
2166         unsigned long flags;
2167 };
2168
2169 static void *timers_start(struct seq_file *m, loff_t *pos)
2170 {
2171         struct timers_private *tp = m->private;
2172
2173         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2174         if (!tp->task)
2175                 return ERR_PTR(-ESRCH);
2176
2177         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2178         if (!tp->sighand)
2179                 return ERR_PTR(-ESRCH);
2180
2181         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2182 }
2183
2184 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2185 {
2186         struct timers_private *tp = m->private;
2187         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2188 }
2189
2190 static void timers_stop(struct seq_file *m, void *v)
2191 {
2192         struct timers_private *tp = m->private;
2193
2194         if (tp->sighand) {
2195                 unlock_task_sighand(tp->task, &tp->flags);
2196                 tp->sighand = NULL;
2197         }
2198
2199         if (tp->task) {
2200                 put_task_struct(tp->task);
2201                 tp->task = NULL;
2202         }
2203 }
2204
2205 static int show_timer(struct seq_file *m, void *v)
2206 {
2207         struct k_itimer *timer;
2208         struct timers_private *tp = m->private;
2209         int notify;
2210         static const char * const nstr[] = {
2211                 [SIGEV_SIGNAL] = "signal",
2212                 [SIGEV_NONE] = "none",
2213                 [SIGEV_THREAD] = "thread",
2214         };
2215
2216         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2217         notify = timer->it_sigev_notify;
2218
2219         seq_printf(m, "ID: %d\n", timer->it_id);
2220         seq_printf(m, "signal: %d/%p\n",
2221                    timer->sigq->info.si_signo,
2222                    timer->sigq->info.si_value.sival_ptr);
2223         seq_printf(m, "notify: %s/%s.%d\n",
2224                    nstr[notify & ~SIGEV_THREAD_ID],
2225                    (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2226                    pid_nr_ns(timer->it_pid, tp->ns));
2227         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2228
2229         return 0;
2230 }
2231
2232 static const struct seq_operations proc_timers_seq_ops = {
2233         .start  = timers_start,
2234         .next   = timers_next,
2235         .stop   = timers_stop,
2236         .show   = show_timer,
2237 };
2238
2239 static int proc_timers_open(struct inode *inode, struct file *file)
2240 {
2241         struct timers_private *tp;
2242
2243         tp = __seq_open_private(file, &proc_timers_seq_ops,
2244                         sizeof(struct timers_private));
2245         if (!tp)
2246                 return -ENOMEM;
2247
2248         tp->pid = proc_pid(inode);
2249         tp->ns = inode->i_sb->s_fs_info;
2250         return 0;
2251 }
2252
2253 static const struct file_operations proc_timers_operations = {
2254         .open           = proc_timers_open,
2255         .read           = seq_read,
2256         .llseek         = seq_lseek,
2257         .release        = seq_release_private,
2258 };
2259
2260 static int proc_pident_instantiate(struct inode *dir,
2261         struct dentry *dentry, struct task_struct *task, const void *ptr)
2262 {
2263         const struct pid_entry *p = ptr;
2264         struct inode *inode;
2265         struct proc_inode *ei;
2266
2267         inode = proc_pid_make_inode(dir->i_sb, task);
2268         if (!inode)
2269                 goto out;
2270
2271         ei = PROC_I(inode);
2272         inode->i_mode = p->mode;
2273         if (S_ISDIR(inode->i_mode))
2274                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2275         if (p->iop)
2276                 inode->i_op = p->iop;
2277         if (p->fop)
2278                 inode->i_fop = p->fop;
2279         ei->op = p->op;
2280         d_set_d_op(dentry, &pid_dentry_operations);
2281         d_add(dentry, inode);
2282         /* Close the race of the process dying before we return the dentry */
2283         if (pid_revalidate(dentry, 0))
2284                 return 0;
2285 out:
2286         return -ENOENT;
2287 }
2288
2289 static struct dentry *proc_pident_lookup(struct inode *dir,
2290                                          struct dentry *dentry,
2291                                          const struct pid_entry *ents,
2292                                          unsigned int nents)
2293 {
2294         int error;
2295         struct task_struct *task = get_proc_task(dir);
2296         const struct pid_entry *p, *last;
2297
2298         error = -ENOENT;
2299
2300         if (!task)
2301                 goto out_no_task;
2302
2303         /*
2304          * Yes, it does not scale. And it should not. Don't add
2305          * new entries into /proc/<tgid>/ without very good reasons.
2306          */
2307         last = &ents[nents - 1];
2308         for (p = ents; p <= last; p++) {
2309                 if (p->len != dentry->d_name.len)
2310                         continue;
2311                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2312                         break;
2313         }
2314         if (p > last)
2315                 goto out;
2316
2317         error = proc_pident_instantiate(dir, dentry, task, p);
2318 out:
2319         put_task_struct(task);
2320 out_no_task:
2321         return ERR_PTR(error);
2322 }
2323
2324 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2325                 const struct pid_entry *ents, unsigned int nents)
2326 {
2327         struct task_struct *task = get_proc_task(file_inode(file));
2328         const struct pid_entry *p;
2329
2330         if (!task)
2331                 return -ENOENT;
2332
2333         if (!dir_emit_dots(file, ctx))
2334                 goto out;
2335
2336         if (ctx->pos >= nents + 2)
2337                 goto out;
2338
2339         for (p = ents + (ctx->pos - 2); p <= ents + nents - 1; p++) {
2340                 if (!proc_fill_cache(file, ctx, p->name, p->len,
2341                                 proc_pident_instantiate, task, p))
2342                         break;
2343                 ctx->pos++;
2344         }
2345 out:
2346         put_task_struct(task);
2347         return 0;
2348 }
2349
2350 #ifdef CONFIG_SECURITY
2351 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2352                                   size_t count, loff_t *ppos)
2353 {
2354         struct inode * inode = file_inode(file);
2355         char *p = NULL;
2356         ssize_t length;
2357         struct task_struct *task = get_proc_task(inode);
2358
2359         if (!task)
2360                 return -ESRCH;
2361
2362         length = security_getprocattr(task,
2363                                       (char*)file->f_path.dentry->d_name.name,
2364                                       &p);
2365         put_task_struct(task);
2366         if (length > 0)
2367                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2368         kfree(p);
2369         return length;
2370 }
2371
2372 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2373                                    size_t count, loff_t *ppos)
2374 {
2375         struct inode * inode = file_inode(file);
2376         void *page;
2377         ssize_t length;
2378         struct task_struct *task = get_proc_task(inode);
2379
2380         length = -ESRCH;
2381         if (!task)
2382                 goto out_no_task;
2383         if (count > PAGE_SIZE)
2384                 count = PAGE_SIZE;
2385
2386         /* No partial writes. */
2387         length = -EINVAL;
2388         if (*ppos != 0)
2389                 goto out;
2390
2391         page = memdup_user(buf, count);
2392         if (IS_ERR(page)) {
2393                 length = PTR_ERR(page);
2394                 goto out;
2395         }
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                                       page, count);
2405         mutex_unlock(&task->signal->cred_guard_mutex);
2406 out_free:
2407         kfree(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         unsigned int val;
2492         int ret;
2493         int i;
2494         unsigned long mask;
2495
2496         ret = kstrtouint_from_user(buf, count, 0, &val);
2497         if (ret < 0)
2498                 return ret;
2499
2500         ret = -ESRCH;
2501         task = get_proc_task(file_inode(file));
2502         if (!task)
2503                 goto out_no_task;
2504
2505         mm = get_task_mm(task);
2506         if (!mm)
2507                 goto out_no_mm;
2508         ret = 0;
2509
2510         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2511                 if (val & mask)
2512                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2513                 else
2514                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2515         }
2516
2517         mmput(mm);
2518  out_no_mm:
2519         put_task_struct(task);
2520  out_no_task:
2521         if (ret < 0)
2522                 return ret;
2523         return count;
2524 }
2525
2526 static const struct file_operations proc_coredump_filter_operations = {
2527         .read           = proc_coredump_filter_read,
2528         .write          = proc_coredump_filter_write,
2529         .llseek         = generic_file_llseek,
2530 };
2531 #endif
2532
2533 #ifdef CONFIG_TASK_IO_ACCOUNTING
2534 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2535 {
2536         struct task_io_accounting acct = task->ioac;
2537         unsigned long flags;
2538         int result;
2539
2540         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2541         if (result)
2542                 return result;
2543
2544         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2545                 result = -EACCES;
2546                 goto out_unlock;
2547         }
2548
2549         if (whole && lock_task_sighand(task, &flags)) {
2550                 struct task_struct *t = task;
2551
2552                 task_io_accounting_add(&acct, &task->signal->ioac);
2553                 while_each_thread(task, t)
2554                         task_io_accounting_add(&acct, &t->ioac);
2555
2556                 unlock_task_sighand(task, &flags);
2557         }
2558         seq_printf(m,
2559                    "rchar: %llu\n"
2560                    "wchar: %llu\n"
2561                    "syscr: %llu\n"
2562                    "syscw: %llu\n"
2563                    "read_bytes: %llu\n"
2564                    "write_bytes: %llu\n"
2565                    "cancelled_write_bytes: %llu\n",
2566                    (unsigned long long)acct.rchar,
2567                    (unsigned long long)acct.wchar,
2568                    (unsigned long long)acct.syscr,
2569                    (unsigned long long)acct.syscw,
2570                    (unsigned long long)acct.read_bytes,
2571                    (unsigned long long)acct.write_bytes,
2572                    (unsigned long long)acct.cancelled_write_bytes);
2573         result = 0;
2574
2575 out_unlock:
2576         mutex_unlock(&task->signal->cred_guard_mutex);
2577         return result;
2578 }
2579
2580 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2581                                   struct pid *pid, struct task_struct *task)
2582 {
2583         return do_io_accounting(task, m, 0);
2584 }
2585
2586 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2587                                    struct pid *pid, struct task_struct *task)
2588 {
2589         return do_io_accounting(task, m, 1);
2590 }
2591 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2592
2593 #ifdef CONFIG_USER_NS
2594 static int proc_id_map_open(struct inode *inode, struct file *file,
2595         const struct seq_operations *seq_ops)
2596 {
2597         struct user_namespace *ns = NULL;
2598         struct task_struct *task;
2599         struct seq_file *seq;
2600         int ret = -EINVAL;
2601
2602         task = get_proc_task(inode);
2603         if (task) {
2604                 rcu_read_lock();
2605                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2606                 rcu_read_unlock();
2607                 put_task_struct(task);
2608         }
2609         if (!ns)
2610                 goto err;
2611
2612         ret = seq_open(file, seq_ops);
2613         if (ret)
2614                 goto err_put_ns;
2615
2616         seq = file->private_data;
2617         seq->private = ns;
2618
2619         return 0;
2620 err_put_ns:
2621         put_user_ns(ns);
2622 err:
2623         return ret;
2624 }
2625
2626 static int proc_id_map_release(struct inode *inode, struct file *file)
2627 {
2628         struct seq_file *seq = file->private_data;
2629         struct user_namespace *ns = seq->private;
2630         put_user_ns(ns);
2631         return seq_release(inode, file);
2632 }
2633
2634 static int proc_uid_map_open(struct inode *inode, struct file *file)
2635 {
2636         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2637 }
2638
2639 static int proc_gid_map_open(struct inode *inode, struct file *file)
2640 {
2641         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2642 }
2643
2644 static int proc_projid_map_open(struct inode *inode, struct file *file)
2645 {
2646         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2647 }
2648
2649 static const struct file_operations proc_uid_map_operations = {
2650         .open           = proc_uid_map_open,
2651         .write          = proc_uid_map_write,
2652         .read           = seq_read,
2653         .llseek         = seq_lseek,
2654         .release        = proc_id_map_release,
2655 };
2656
2657 static const struct file_operations proc_gid_map_operations = {
2658         .open           = proc_gid_map_open,
2659         .write          = proc_gid_map_write,
2660         .read           = seq_read,
2661         .llseek         = seq_lseek,
2662         .release        = proc_id_map_release,
2663 };
2664
2665 static const struct file_operations proc_projid_map_operations = {
2666         .open           = proc_projid_map_open,
2667         .write          = proc_projid_map_write,
2668         .read           = seq_read,
2669         .llseek         = seq_lseek,
2670         .release        = proc_id_map_release,
2671 };
2672
2673 static int proc_setgroups_open(struct inode *inode, struct file *file)
2674 {
2675         struct user_namespace *ns = NULL;
2676         struct task_struct *task;
2677         int ret;
2678
2679         ret = -ESRCH;
2680         task = get_proc_task(inode);
2681         if (task) {
2682                 rcu_read_lock();
2683                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2684                 rcu_read_unlock();
2685                 put_task_struct(task);
2686         }
2687         if (!ns)
2688                 goto err;
2689
2690         if (file->f_mode & FMODE_WRITE) {
2691                 ret = -EACCES;
2692                 if (!ns_capable(ns, CAP_SYS_ADMIN))
2693                         goto err_put_ns;
2694         }
2695
2696         ret = single_open(file, &proc_setgroups_show, ns);
2697         if (ret)
2698                 goto err_put_ns;
2699
2700         return 0;
2701 err_put_ns:
2702         put_user_ns(ns);
2703 err:
2704         return ret;
2705 }
2706
2707 static int proc_setgroups_release(struct inode *inode, struct file *file)
2708 {
2709         struct seq_file *seq = file->private_data;
2710         struct user_namespace *ns = seq->private;
2711         int ret = single_release(inode, file);
2712         put_user_ns(ns);
2713         return ret;
2714 }
2715
2716 static const struct file_operations proc_setgroups_operations = {
2717         .open           = proc_setgroups_open,
2718         .write          = proc_setgroups_write,
2719         .read           = seq_read,
2720         .llseek         = seq_lseek,
2721         .release        = proc_setgroups_release,
2722 };
2723 #endif /* CONFIG_USER_NS */
2724
2725 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2726                                 struct pid *pid, struct task_struct *task)
2727 {
2728         int err = lock_trace(task);
2729         if (!err) {
2730                 seq_printf(m, "%08x\n", task->personality);
2731                 unlock_trace(task);
2732         }
2733         return err;
2734 }
2735
2736 /*
2737  * Thread groups
2738  */
2739 static const struct file_operations proc_task_operations;
2740 static const struct inode_operations proc_task_inode_operations;
2741
2742 static const struct pid_entry tgid_base_stuff[] = {
2743         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2744         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2745         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2746         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2747         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2748 #ifdef CONFIG_NET
2749         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2750 #endif
2751         REG("environ",    S_IRUSR, proc_environ_operations),
2752         ONE("auxv",       S_IRUSR, proc_pid_auxv),
2753         ONE("status",     S_IRUGO, proc_pid_status),
2754         ONE("personality", S_IRUSR, proc_pid_personality),
2755         ONE("limits",     S_IRUGO, proc_pid_limits),
2756 #ifdef CONFIG_SCHED_DEBUG
2757         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2758 #endif
2759 #ifdef CONFIG_SCHED_AUTOGROUP
2760         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2761 #endif
2762         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2763 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2764         ONE("syscall",    S_IRUSR, proc_pid_syscall),
2765 #endif
2766         REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
2767         ONE("stat",       S_IRUGO, proc_tgid_stat),
2768         ONE("statm",      S_IRUGO, proc_pid_statm),
2769         REG("maps",       S_IRUGO, proc_pid_maps_operations),
2770 #ifdef CONFIG_NUMA
2771         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2772 #endif
2773         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2774         LNK("cwd",        proc_cwd_link),
2775         LNK("root",       proc_root_link),
2776         LNK("exe",        proc_exe_link),
2777         REG("mounts",     S_IRUGO, proc_mounts_operations),
2778         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2779         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2780 #ifdef CONFIG_PROC_PAGE_MONITOR
2781         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2782         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2783         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2784 #endif
2785 #ifdef CONFIG_SECURITY
2786         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2787 #endif
2788 #ifdef CONFIG_KALLSYMS
2789         ONE("wchan",      S_IRUGO, proc_pid_wchan),
2790 #endif
2791 #ifdef CONFIG_STACKTRACE
2792         ONE("stack",      S_IRUSR, proc_pid_stack),
2793 #endif
2794 #ifdef CONFIG_SCHED_INFO
2795         ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
2796 #endif
2797 #ifdef CONFIG_LATENCYTOP
2798         REG("latency",  S_IRUGO, proc_lstats_operations),
2799 #endif
2800 #ifdef CONFIG_PROC_PID_CPUSET
2801         ONE("cpuset",     S_IRUGO, proc_cpuset_show),
2802 #endif
2803 #ifdef CONFIG_CGROUPS
2804         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
2805 #endif
2806         ONE("oom_score",  S_IRUGO, proc_oom_score),
2807         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
2808         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2809 #ifdef CONFIG_AUDITSYSCALL
2810         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2811         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2812 #endif
2813 #ifdef CONFIG_FAULT_INJECTION
2814         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2815 #endif
2816 #ifdef CONFIG_ELF_CORE
2817         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2818 #endif
2819 #ifdef CONFIG_TASK_IO_ACCOUNTING
2820         ONE("io",       S_IRUSR, proc_tgid_io_accounting),
2821 #endif
2822 #ifdef CONFIG_HARDWALL
2823         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
2824 #endif
2825 #ifdef CONFIG_USER_NS
2826         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
2827         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
2828         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
2829         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
2830 #endif
2831 #ifdef CONFIG_CHECKPOINT_RESTORE
2832         REG("timers",     S_IRUGO, proc_timers_operations),
2833 #endif
2834 };
2835
2836 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
2837 {
2838         return proc_pident_readdir(file, ctx,
2839                                    tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2840 }
2841
2842 static const struct file_operations proc_tgid_base_operations = {
2843         .read           = generic_read_dir,
2844         .iterate        = proc_tgid_base_readdir,
2845         .llseek         = default_llseek,
2846 };
2847
2848 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
2849 {
2850         return proc_pident_lookup(dir, dentry,
2851                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2852 }
2853
2854 static const struct inode_operations proc_tgid_base_inode_operations = {
2855         .lookup         = proc_tgid_base_lookup,
2856         .getattr        = pid_getattr,
2857         .setattr        = proc_setattr,
2858         .permission     = proc_pid_permission,
2859 };
2860
2861 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2862 {
2863         struct dentry *dentry, *leader, *dir;
2864         char buf[PROC_NUMBUF];
2865         struct qstr name;
2866
2867         name.name = buf;
2868         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2869         /* no ->d_hash() rejects on procfs */
2870         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2871         if (dentry) {
2872                 d_invalidate(dentry);
2873                 dput(dentry);
2874         }
2875
2876         if (pid == tgid)
2877                 return;
2878
2879         name.name = buf;
2880         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2881         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2882         if (!leader)
2883                 goto out;
2884
2885         name.name = "task";
2886         name.len = strlen(name.name);
2887         dir = d_hash_and_lookup(leader, &name);
2888         if (!dir)
2889                 goto out_put_leader;
2890
2891         name.name = buf;
2892         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2893         dentry = d_hash_and_lookup(dir, &name);
2894         if (dentry) {
2895                 d_invalidate(dentry);
2896                 dput(dentry);
2897         }
2898
2899         dput(dir);
2900 out_put_leader:
2901         dput(leader);
2902 out:
2903         return;
2904 }
2905
2906 /**
2907  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2908  * @task: task that should be flushed.
2909  *
2910  * When flushing dentries from proc, one needs to flush them from global
2911  * proc (proc_mnt) and from all the namespaces' procs this task was seen
2912  * in. This call is supposed to do all of this job.
2913  *
2914  * Looks in the dcache for
2915  * /proc/@pid
2916  * /proc/@tgid/task/@pid
2917  * if either directory is present flushes it and all of it'ts children
2918  * from the dcache.
2919  *
2920  * It is safe and reasonable to cache /proc entries for a task until
2921  * that task exits.  After that they just clog up the dcache with
2922  * useless entries, possibly causing useful dcache entries to be
2923  * flushed instead.  This routine is proved to flush those useless
2924  * dcache entries at process exit time.
2925  *
2926  * NOTE: This routine is just an optimization so it does not guarantee
2927  *       that no dcache entries will exist at process exit time it
2928  *       just makes it very unlikely that any will persist.
2929  */
2930
2931 void proc_flush_task(struct task_struct *task)
2932 {
2933         int i;
2934         struct pid *pid, *tgid;
2935         struct upid *upid;
2936
2937         pid = task_pid(task);
2938         tgid = task_tgid(task);
2939
2940         for (i = 0; i <= pid->level; i++) {
2941                 upid = &pid->numbers[i];
2942                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2943                                         tgid->numbers[i].nr);
2944         }
2945 }
2946
2947 static int proc_pid_instantiate(struct inode *dir,
2948                                    struct dentry * dentry,
2949                                    struct task_struct *task, const void *ptr)
2950 {
2951         struct inode *inode;
2952
2953         inode = proc_pid_make_inode(dir->i_sb, task);
2954         if (!inode)
2955                 goto out;
2956
2957         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2958         inode->i_op = &proc_tgid_base_inode_operations;
2959         inode->i_fop = &proc_tgid_base_operations;
2960         inode->i_flags|=S_IMMUTABLE;
2961
2962         set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
2963                                                   ARRAY_SIZE(tgid_base_stuff)));
2964
2965         d_set_d_op(dentry, &pid_dentry_operations);
2966
2967         d_add(dentry, inode);
2968         /* Close the race of the process dying before we return the dentry */
2969         if (pid_revalidate(dentry, 0))
2970                 return 0;
2971 out:
2972         return -ENOENT;
2973 }
2974
2975 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
2976 {
2977         int result = -ENOENT;
2978         struct task_struct *task;
2979         unsigned tgid;
2980         struct pid_namespace *ns;
2981
2982         tgid = name_to_int(&dentry->d_name);
2983         if (tgid == ~0U)
2984                 goto out;
2985
2986         ns = dentry->d_sb->s_fs_info;
2987         rcu_read_lock();
2988         task = find_task_by_pid_ns(tgid, ns);
2989         if (task)
2990                 get_task_struct(task);
2991         rcu_read_unlock();
2992         if (!task)
2993                 goto out;
2994
2995         result = proc_pid_instantiate(dir, dentry, task, NULL);
2996         put_task_struct(task);
2997 out:
2998         return ERR_PTR(result);
2999 }
3000
3001 /*
3002  * Find the first task with tgid >= tgid
3003  *
3004  */
3005 struct tgid_iter {
3006         unsigned int tgid;
3007         struct task_struct *task;
3008 };
3009 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3010 {
3011         struct pid *pid;
3012
3013         if (iter.task)
3014                 put_task_struct(iter.task);
3015         rcu_read_lock();
3016 retry:
3017         iter.task = NULL;
3018         pid = find_ge_pid(iter.tgid, ns);
3019         if (pid) {
3020                 iter.tgid = pid_nr_ns(pid, ns);
3021                 iter.task = pid_task(pid, PIDTYPE_PID);
3022                 /* What we to know is if the pid we have find is the
3023                  * pid of a thread_group_leader.  Testing for task
3024                  * being a thread_group_leader is the obvious thing
3025                  * todo but there is a window when it fails, due to
3026                  * the pid transfer logic in de_thread.
3027                  *
3028                  * So we perform the straight forward test of seeing
3029                  * if the pid we have found is the pid of a thread
3030                  * group leader, and don't worry if the task we have
3031                  * found doesn't happen to be a thread group leader.
3032                  * As we don't care in the case of readdir.
3033                  */
3034                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3035                         iter.tgid += 1;
3036                         goto retry;
3037                 }
3038                 get_task_struct(iter.task);
3039         }
3040         rcu_read_unlock();
3041         return iter;
3042 }
3043
3044 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3045
3046 /* for the /proc/ directory itself, after non-process stuff has been done */
3047 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3048 {
3049         struct tgid_iter iter;
3050         struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info;
3051         loff_t pos = ctx->pos;
3052
3053         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3054                 return 0;
3055
3056         if (pos == TGID_OFFSET - 2) {
3057                 struct inode *inode = d_inode(ns->proc_self);
3058                 if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3059                         return 0;
3060                 ctx->pos = pos = pos + 1;
3061         }
3062         if (pos == TGID_OFFSET - 1) {
3063                 struct inode *inode = d_inode(ns->proc_thread_self);
3064                 if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3065                         return 0;
3066                 ctx->pos = pos = pos + 1;
3067         }
3068         iter.tgid = pos - TGID_OFFSET;
3069         iter.task = NULL;
3070         for (iter = next_tgid(ns, iter);
3071              iter.task;
3072              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3073                 char name[PROC_NUMBUF];
3074                 int len;
3075                 if (!has_pid_permissions(ns, iter.task, 2))
3076                         continue;
3077
3078                 len = snprintf(name, sizeof(name), "%d", iter.tgid);
3079                 ctx->pos = iter.tgid + TGID_OFFSET;
3080                 if (!proc_fill_cache(file, ctx, name, len,
3081                                      proc_pid_instantiate, iter.task, NULL)) {
3082                         put_task_struct(iter.task);
3083                         return 0;
3084                 }
3085         }
3086         ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3087         return 0;
3088 }
3089
3090 /*
3091  * Tasks
3092  */
3093 static const struct pid_entry tid_base_stuff[] = {
3094         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3095         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3096         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3097 #ifdef CONFIG_NET
3098         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3099 #endif
3100         REG("environ",   S_IRUSR, proc_environ_operations),
3101         ONE("auxv",      S_IRUSR, proc_pid_auxv),
3102         ONE("status",    S_IRUGO, proc_pid_status),
3103         ONE("personality", S_IRUSR, proc_pid_personality),
3104         ONE("limits",    S_IRUGO, proc_pid_limits),
3105 #ifdef CONFIG_SCHED_DEBUG
3106         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3107 #endif
3108         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3109 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3110         ONE("syscall",   S_IRUSR, proc_pid_syscall),
3111 #endif
3112         REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3113         ONE("stat",      S_IRUGO, proc_tid_stat),
3114         ONE("statm",     S_IRUGO, proc_pid_statm),
3115         REG("maps",      S_IRUGO, proc_tid_maps_operations),
3116 #ifdef CONFIG_PROC_CHILDREN
3117         REG("children",  S_IRUGO, proc_tid_children_operations),
3118 #endif
3119 #ifdef CONFIG_NUMA
3120         REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3121 #endif
3122         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3123         LNK("cwd",       proc_cwd_link),
3124         LNK("root",      proc_root_link),
3125         LNK("exe",       proc_exe_link),
3126         REG("mounts",    S_IRUGO, proc_mounts_operations),
3127         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3128 #ifdef CONFIG_PROC_PAGE_MONITOR
3129         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3130         REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3131         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3132 #endif
3133 #ifdef CONFIG_SECURITY
3134         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3135 #endif
3136 #ifdef CONFIG_KALLSYMS
3137         ONE("wchan",     S_IRUGO, proc_pid_wchan),
3138 #endif
3139 #ifdef CONFIG_STACKTRACE
3140         ONE("stack",      S_IRUSR, proc_pid_stack),
3141 #endif
3142 #ifdef CONFIG_SCHED_INFO
3143         ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3144 #endif
3145 #ifdef CONFIG_LATENCYTOP
3146         REG("latency",  S_IRUGO, proc_lstats_operations),
3147 #endif
3148 #ifdef CONFIG_PROC_PID_CPUSET
3149         ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3150 #endif
3151 #ifdef CONFIG_CGROUPS
3152         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3153 #endif
3154         ONE("oom_score", S_IRUGO, proc_oom_score),
3155         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3156         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3157 #ifdef CONFIG_AUDITSYSCALL
3158         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3159         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3160 #endif
3161 #ifdef CONFIG_FAULT_INJECTION
3162         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3163 #endif
3164 #ifdef CONFIG_TASK_IO_ACCOUNTING
3165         ONE("io",       S_IRUSR, proc_tid_io_accounting),
3166 #endif
3167 #ifdef CONFIG_HARDWALL
3168         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
3169 #endif
3170 #ifdef CONFIG_USER_NS
3171         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3172         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3173         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3174         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3175 #endif
3176 };
3177
3178 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3179 {
3180         return proc_pident_readdir(file, ctx,
3181                                    tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3182 }
3183
3184 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3185 {
3186         return proc_pident_lookup(dir, dentry,
3187                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3188 }
3189
3190 static const struct file_operations proc_tid_base_operations = {
3191         .read           = generic_read_dir,
3192         .iterate        = proc_tid_base_readdir,
3193         .llseek         = default_llseek,
3194 };
3195
3196 static const struct inode_operations proc_tid_base_inode_operations = {
3197         .lookup         = proc_tid_base_lookup,
3198         .getattr        = pid_getattr,
3199         .setattr        = proc_setattr,
3200 };
3201
3202 static int proc_task_instantiate(struct inode *dir,
3203         struct dentry *dentry, struct task_struct *task, const void *ptr)
3204 {
3205         struct inode *inode;
3206         inode = proc_pid_make_inode(dir->i_sb, task);
3207
3208         if (!inode)
3209                 goto out;
3210         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3211         inode->i_op = &proc_tid_base_inode_operations;
3212         inode->i_fop = &proc_tid_base_operations;
3213         inode->i_flags|=S_IMMUTABLE;
3214
3215         set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
3216                                                   ARRAY_SIZE(tid_base_stuff)));
3217
3218         d_set_d_op(dentry, &pid_dentry_operations);
3219
3220         d_add(dentry, inode);
3221         /* Close the race of the process dying before we return the dentry */
3222         if (pid_revalidate(dentry, 0))
3223                 return 0;
3224 out:
3225         return -ENOENT;
3226 }
3227
3228 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3229 {
3230         int result = -ENOENT;
3231         struct task_struct *task;
3232         struct task_struct *leader = get_proc_task(dir);
3233         unsigned tid;
3234         struct pid_namespace *ns;
3235
3236         if (!leader)
3237                 goto out_no_task;
3238
3239         tid = name_to_int(&dentry->d_name);
3240         if (tid == ~0U)
3241                 goto out;
3242
3243         ns = dentry->d_sb->s_fs_info;
3244         rcu_read_lock();
3245         task = find_task_by_pid_ns(tid, ns);
3246         if (task)
3247                 get_task_struct(task);
3248         rcu_read_unlock();
3249         if (!task)
3250                 goto out;
3251         if (!same_thread_group(leader, task))
3252                 goto out_drop_task;
3253
3254         result = proc_task_instantiate(dir, dentry, task, NULL);
3255 out_drop_task:
3256         put_task_struct(task);
3257 out:
3258         put_task_struct(leader);
3259 out_no_task:
3260         return ERR_PTR(result);
3261 }
3262
3263 /*
3264  * Find the first tid of a thread group to return to user space.
3265  *
3266  * Usually this is just the thread group leader, but if the users
3267  * buffer was too small or there was a seek into the middle of the
3268  * directory we have more work todo.
3269  *
3270  * In the case of a short read we start with find_task_by_pid.
3271  *
3272  * In the case of a seek we start with the leader and walk nr
3273  * threads past it.
3274  */
3275 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3276                                         struct pid_namespace *ns)
3277 {
3278         struct task_struct *pos, *task;
3279         unsigned long nr = f_pos;
3280
3281         if (nr != f_pos)        /* 32bit overflow? */
3282                 return NULL;
3283
3284         rcu_read_lock();
3285         task = pid_task(pid, PIDTYPE_PID);
3286         if (!task)
3287                 goto fail;
3288
3289         /* Attempt to start with the tid of a thread */
3290         if (tid && nr) {
3291                 pos = find_task_by_pid_ns(tid, ns);
3292                 if (pos && same_thread_group(pos, task))
3293                         goto found;
3294         }
3295
3296         /* If nr exceeds the number of threads there is nothing todo */
3297         if (nr >= get_nr_threads(task))
3298                 goto fail;
3299
3300         /* If we haven't found our starting place yet start
3301          * with the leader and walk nr threads forward.
3302          */
3303         pos = task = task->group_leader;
3304         do {
3305                 if (!nr--)
3306                         goto found;
3307         } while_each_thread(task, pos);
3308 fail:
3309         pos = NULL;
3310         goto out;
3311 found:
3312         get_task_struct(pos);
3313 out:
3314         rcu_read_unlock();
3315         return pos;
3316 }
3317
3318 /*
3319  * Find the next thread in the thread list.
3320  * Return NULL if there is an error or no next thread.
3321  *
3322  * The reference to the input task_struct is released.
3323  */
3324 static struct task_struct *next_tid(struct task_struct *start)
3325 {
3326         struct task_struct *pos = NULL;
3327         rcu_read_lock();
3328         if (pid_alive(start)) {
3329                 pos = next_thread(start);
3330                 if (thread_group_leader(pos))
3331                         pos = NULL;
3332                 else
3333                         get_task_struct(pos);
3334         }
3335         rcu_read_unlock();
3336         put_task_struct(start);
3337         return pos;
3338 }
3339
3340 /* for the /proc/TGID/task/ directories */
3341 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3342 {
3343         struct inode *inode = file_inode(file);
3344         struct task_struct *task;
3345         struct pid_namespace *ns;
3346         int tid;
3347
3348         if (proc_inode_is_dead(inode))
3349                 return -ENOENT;
3350
3351         if (!dir_emit_dots(file, ctx))
3352                 return 0;
3353
3354         /* f_version caches the tgid value that the last readdir call couldn't
3355          * return. lseek aka telldir automagically resets f_version to 0.
3356          */
3357         ns = inode->i_sb->s_fs_info;
3358         tid = (int)file->f_version;
3359         file->f_version = 0;
3360         for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3361              task;
3362              task = next_tid(task), ctx->pos++) {
3363                 char name[PROC_NUMBUF];
3364                 int len;
3365                 tid = task_pid_nr_ns(task, ns);
3366                 len = snprintf(name, sizeof(name), "%d", tid);
3367                 if (!proc_fill_cache(file, ctx, name, len,
3368                                 proc_task_instantiate, task, NULL)) {
3369                         /* returning this tgid failed, save it as the first
3370                          * pid for the next readir call */
3371                         file->f_version = (u64)tid;
3372                         put_task_struct(task);
3373                         break;
3374                 }
3375         }
3376
3377         return 0;
3378 }
3379
3380 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3381 {
3382         struct inode *inode = d_inode(dentry);
3383         struct task_struct *p = get_proc_task(inode);
3384         generic_fillattr(inode, stat);
3385
3386         if (p) {
3387                 stat->nlink += get_nr_threads(p);
3388                 put_task_struct(p);
3389         }
3390
3391         return 0;
3392 }
3393
3394 static const struct inode_operations proc_task_inode_operations = {
3395         .lookup         = proc_task_lookup,
3396         .getattr        = proc_task_getattr,
3397         .setattr        = proc_setattr,
3398         .permission     = proc_pid_permission,
3399 };
3400
3401 static const struct file_operations proc_task_operations = {
3402         .read           = generic_read_dir,
3403         .iterate        = proc_task_readdir,
3404         .llseek         = default_llseek,
3405 };