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   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/rcupdate.h>
  67 #include <linux/kallsyms.h>
  68 #include <linux/stacktrace.h>
  69 #include <linux/resource.h>
  70 #include <linux/module.h>
  71 #include <linux/mount.h>
  72 #include <linux/security.h>
  73 #include <linux/ptrace.h>
  74 #include <linux/tracehook.h>
  75 #include <linux/cgroup.h>
  76 #include <linux/cpuset.h>
  77 #include <linux/audit.h>
  78 #include <linux/poll.h>
  79 #include <linux/nsproxy.h>
  80 #include <linux/oom.h>
  81 #include <linux/elf.h>
  82 #include <linux/pid_namespace.h>
  83 #include "internal.h"
  84
  85 /* NOTE:
  86  *      Implementing inode permission operations in /proc is almost
  87  *      certainly an error.  Permission checks need to happen during
  88  *      each system call not at open time.  The reason is that most of
  89  *      what we wish to check for permissions in /proc varies at runtime.
  90  *
  91  *      The classic example of a problem is opening file descriptors
  92  *      in /proc for a task before it execs a suid executable.
  93  */
  94
  95 struct pid_entry {
  96         char *name;
  97         int len;
  98         mode_t mode;
  99         const struct inode_operations *iop;
 100         const struct file_operations *fop;
 101         union proc_op op;
 102 };
 103
 104 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
 105         .name = (NAME),                                 \
 106         .len  = sizeof(NAME) - 1,                       \
 107         .mode = MODE,                                   \
 108         .iop  = IOP,                                    \
 109         .fop  = FOP,                                    \
 110         .op   = OP,                                     \
 111 }
 112
 113 #define DIR(NAME, MODE, iops, fops)     \
 114         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
 115 #define LNK(NAME, get_link)                                     \
 116         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
 117                 &proc_pid_link_inode_operations, NULL,          \
 118                 { .proc_get_link = get_link } )
 119 #define REG(NAME, MODE, fops)                           \
 120         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
 121 #define INF(NAME, MODE, read)                           \
 122         NOD(NAME, (S_IFREG|(MODE)),                     \
 123                 NULL, &proc_info_file_operations,       \
 124                 { .proc_read = read } )
 125 #define ONE(NAME, MODE, show)                           \
 126         NOD(NAME, (S_IFREG|(MODE)),                     \
 127                 NULL, &proc_single_file_operations,     \
 128                 { .proc_show = show } )
 129
 130 /*
 131  * Count the number of hardlinks for the pid_entry table, excluding the .
 132  * and .. links.
 133  */
 134 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
 135         unsigned int n)
 136 {
 137         unsigned int i;
 138         unsigned int count;
 139
 140         count = 0;
 141         for (i = 0; i < n; ++i) {
 142                 if (S_ISDIR(entries[i].mode))
 143                         ++count;
 144         }
 145
 146         return count;
 147 }
 148
 149 static struct fs_struct *get_fs_struct(struct task_struct *task)
 150 {
 151         struct fs_struct *fs;
 152         task_lock(task);
 153         fs = task->fs;
 154         if(fs)
 155                 atomic_inc(&fs->count);
 156         task_unlock(task);
 157         return fs;
 158 }
 159
 160 static int get_nr_threads(struct task_struct *tsk)
 161 {
 162         unsigned long flags;
 163         int count = 0;
 164
 165         if (lock_task_sighand(tsk, &flags)) {
 166                 count = atomic_read(&tsk->signal->count);
 167                 unlock_task_sighand(tsk, &flags);
 168         }
 169         return count;
 170 }
 171
 172 static int proc_cwd_link(struct inode *inode, struct path *path)
 173 {
 174         struct task_struct *task = get_proc_task(inode);
 175         struct fs_struct *fs = NULL;
 176         int result = -ENOENT;
 177
 178         if (task) {
 179                 fs = get_fs_struct(task);
 180                 put_task_struct(task);
 181         }
 182         if (fs) {
 183                 read_lock(&fs->lock);
 184                 *path = fs->pwd;
 185                 path_get(&fs->pwd);
 186                 read_unlock(&fs->lock);
 187                 result = 0;
 188                 put_fs_struct(fs);
 189         }
 190         return result;
 191 }
 192
 193 static int proc_root_link(struct inode *inode, struct path *path)
 194 {
 195         struct task_struct *task = get_proc_task(inode);
 196         struct fs_struct *fs = NULL;
 197         int result = -ENOENT;
 198
 199         if (task) {
 200                 fs = get_fs_struct(task);
 201                 put_task_struct(task);
 202         }
 203         if (fs) {
 204                 read_lock(&fs->lock);
 205                 *path = fs->root;
 206                 path_get(&fs->root);
 207                 read_unlock(&fs->lock);
 208                 result = 0;
 209                 put_fs_struct(fs);
 210         }
 211         return result;
 212 }
 213
 214 /*
 215  * Return zero if current may access user memory in @task, -error if not.
 216  */
 217 static int check_mem_permission(struct task_struct *task)
 218 {
 219         /*
 220          * A task can always look at itself, in case it chooses
 221          * to use system calls instead of load instructions.
 222          */
 223         if (task == current)
 224                 return 0;
 225
 226         /*
 227          * If current is actively ptrace'ing, and would also be
 228          * permitted to freshly attach with ptrace now, permit it.
 229          */
 230         if (task_is_stopped_or_traced(task)) {
 231                 int match;
 232                 rcu_read_lock();
 233                 match = (tracehook_tracer_task(task) == current);
 234                 rcu_read_unlock();
 235                 if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
 236                         return 0;
 237         }
 238
 239         /*
 240          * Noone else is allowed.
 241          */
 242         return -EPERM;
 243 }
 244
 245 struct mm_struct *mm_for_maps(struct task_struct *task)
 246 {
 247         struct mm_struct *mm = get_task_mm(task);
 248         if (!mm)
 249                 return NULL;
 250         down_read(&mm->mmap_sem);
 251         task_lock(task);
 252         if (task->mm != mm)
 253                 goto out;
 254         if (task->mm != current->mm &&
 255             __ptrace_may_access(task, PTRACE_MODE_READ) < 0)
 256                 goto out;
 257         task_unlock(task);
 258         return mm;
 259 out:
 260         task_unlock(task);
 261         up_read(&mm->mmap_sem);
 262         mmput(mm);
 263         return NULL;
 264 }
 265
 266 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
 267 {
 268         int res = 0;
 269         unsigned int len;
 270         struct mm_struct *mm = get_task_mm(task);
 271         if (!mm)
 272                 goto out;
 273         if (!mm->arg_end)
 274                 goto out_mm;    /* Shh! No looking before we're done */
 275
 276         len = mm->arg_end - mm->arg_start;
 277
 278         if (len > PAGE_SIZE)
 279                 len = PAGE_SIZE;
 280
 281         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 282
 283         // If the nul at the end of args has been overwritten, then
 284         // assume application is using setproctitle(3).
 285         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
 286                 len = strnlen(buffer, res);
 287                 if (len < res) {
 288                     res = len;
 289                 } else {
 290                         len = mm->env_end - mm->env_start;
 291                         if (len > PAGE_SIZE - res)
 292                                 len = PAGE_SIZE - res;
 293                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
 294                         res = strnlen(buffer, res);
 295                 }
 296         }
 297 out_mm:
 298         mmput(mm);
 299 out:
 300         return res;
 301 }
 302
 303 static int proc_pid_auxv(struct task_struct *task, char *buffer)
 304 {
 305         int res = 0;
 306         struct mm_struct *mm = get_task_mm(task);
 307         if (mm) {
 308                 unsigned int nwords = 0;
 309                 do {
 310                         nwords += 2;
 311                 } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
 312                 res = nwords * sizeof(mm->saved_auxv[0]);
 313                 if (res > PAGE_SIZE)
 314                         res = PAGE_SIZE;
 315                 memcpy(buffer, mm->saved_auxv, res);
 316                 mmput(mm);
 317         }
 318         return res;
 319 }
 320
 321
 322 #ifdef CONFIG_KALLSYMS
 323 /*
 324  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
 325  * Returns the resolved symbol.  If that fails, simply return the address.
 326  */
 327 static int proc_pid_wchan(struct task_struct *task, char *buffer)
 328 {
 329         unsigned long wchan;
 330         char symname[KSYM_NAME_LEN];
 331
 332         wchan = get_wchan(task);
 333
 334         if (lookup_symbol_name(wchan, symname) < 0)
 335                 return sprintf(buffer, "%lu", wchan);
 336         else
 337                 return sprintf(buffer, "%s", symname);
 338 }
 339 #endif /* CONFIG_KALLSYMS */
 340
 341 #ifdef CONFIG_STACKTRACE
 342
 343 #define MAX_STACK_TRACE_DEPTH   64
 344
 345 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
 346                           struct pid *pid, struct task_struct *task)
 347 {
 348         struct stack_trace trace;
 349         unsigned long *entries;
 350         int i;
 351
 352         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
 353         if (!entries)
 354                 return -ENOMEM;
 355
 356         trace.nr_entries        = 0;
 357         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
 358         trace.entries           = entries;
 359         trace.skip              = 0;
 360         save_stack_trace_tsk(task, &trace);
 361
 362         for (i = 0; i < trace.nr_entries; i++) {
 363                 seq_printf(m, "[<%p>] %pS\n",
 364                            (void *)entries[i], (void *)entries[i]);
 365         }
 366         kfree(entries);
 367
 368         return 0;
 369 }
 370 #endif
 371
 372 #ifdef CONFIG_SCHEDSTATS
 373 /*
 374  * Provides /proc/PID/schedstat
 375  */
 376 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
 377 {
 378         return sprintf(buffer, "%llu %llu %lu\n",
 379                         (unsigned long long)task->se.sum_exec_runtime,
 380                         (unsigned long long)task->sched_info.run_delay,
 381                         task->sched_info.pcount);
 382 }
 383 #endif
 384
 385 #ifdef CONFIG_LATENCYTOP
 386 static int lstats_show_proc(struct seq_file *m, void *v)
 387 {
 388         int i;
 389         struct inode *inode = m->private;
 390         struct task_struct *task = get_proc_task(inode);
 391
 392         if (!task)
 393                 return -ESRCH;
 394         seq_puts(m, "Latency Top version : v0.1\n");
 395         for (i = 0; i < 32; i++) {
 396                 if (task->latency_record[i].backtrace[0]) {
 397                         int q;
 398                         seq_printf(m, "%i %li %li ",
 399                                 task->latency_record[i].count,
 400                                 task->latency_record[i].time,
 401                                 task->latency_record[i].max);
 402                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 403                                 char sym[KSYM_SYMBOL_LEN];
 404                                 char *c;
 405                                 if (!task->latency_record[i].backtrace[q])
 406                                         break;
 407                                 if (task->latency_record[i].backtrace[q] == ULONG_MAX)
 408                                         break;
 409                                 sprint_symbol(sym, task->latency_record[i].backtrace[q]);
 410                                 c = strchr(sym, '+');
 411                                 if (c)
 412                                         *c = 0;
 413                                 seq_printf(m, "%s ", sym);
 414                         }
 415                         seq_printf(m, "\n");
 416                 }
 417
 418         }
 419         put_task_struct(task);
 420         return 0;
 421 }
 422
 423 static int lstats_open(struct inode *inode, struct file *file)
 424 {
 425         return single_open(file, lstats_show_proc, inode);
 426 }
 427
 428 static ssize_t lstats_write(struct file *file, const char __user *buf,
 429                             size_t count, loff_t *offs)
 430 {
 431         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 432
 433         if (!task)
 434                 return -ESRCH;
 435         clear_all_latency_tracing(task);
 436         put_task_struct(task);
 437
 438         return count;
 439 }
 440
 441 static const struct file_operations proc_lstats_operations = {
 442         .open           = lstats_open,
 443         .read           = seq_read,
 444         .write          = lstats_write,
 445         .llseek         = seq_lseek,
 446         .release        = single_release,
 447 };
 448
 449 #endif
 450
 451 /* The badness from the OOM killer */
 452 unsigned long badness(struct task_struct *p, unsigned long uptime);
 453 static int proc_oom_score(struct task_struct *task, char *buffer)
 454 {
 455         unsigned long points;
 456         struct timespec uptime;
 457
 458         do_posix_clock_monotonic_gettime(&uptime);
 459         read_lock(&tasklist_lock);
 460         points = badness(task, uptime.tv_sec);
 461         read_unlock(&tasklist_lock);
 462         return sprintf(buffer, "%lu\n", points);
 463 }
 464
 465 struct limit_names {
 466         char *name;
 467         char *unit;
 468 };
 469
 470 static const struct limit_names lnames[RLIM_NLIMITS] = {
 471         [RLIMIT_CPU] = {"Max cpu time", "ms"},
 472         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
 473         [RLIMIT_DATA] = {"Max data size", "bytes"},
 474         [RLIMIT_STACK] = {"Max stack size", "bytes"},
 475         [RLIMIT_CORE] = {"Max core file size", "bytes"},
 476         [RLIMIT_RSS] = {"Max resident set", "bytes"},
 477         [RLIMIT_NPROC] = {"Max processes", "processes"},
 478         [RLIMIT_NOFILE] = {"Max open files", "files"},
 479         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
 480         [RLIMIT_AS] = {"Max address space", "bytes"},
 481         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
 482         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
 483         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
 484         [RLIMIT_NICE] = {"Max nice priority", NULL},
 485         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
 486         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
 487 };
 488
 489 /* Display limits for a process */
 490 static int proc_pid_limits(struct task_struct *task, char *buffer)
 491 {
 492         unsigned int i;
 493         int count = 0;
 494         unsigned long flags;
 495         char *bufptr = buffer;
 496
 497         struct rlimit rlim[RLIM_NLIMITS];
 498
 499         if (!lock_task_sighand(task, &flags))
 500                 return 0;
 501         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
 502         unlock_task_sighand(task, &flags);
 503
 504         /*
 505          * print the file header
 506          */
 507         count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
 508                         "Limit", "Soft Limit", "Hard Limit", "Units");
 509
 510         for (i = 0; i < RLIM_NLIMITS; i++) {
 511                 if (rlim[i].rlim_cur == RLIM_INFINITY)
 512                         count += sprintf(&bufptr[count], "%-25s %-20s ",
 513                                          lnames[i].name, "unlimited");
 514                 else
 515                         count += sprintf(&bufptr[count], "%-25s %-20lu ",
 516                                          lnames[i].name, rlim[i].rlim_cur);
 517
 518                 if (rlim[i].rlim_max == RLIM_INFINITY)
 519                         count += sprintf(&bufptr[count], "%-20s ", "unlimited");
 520                 else
 521                         count += sprintf(&bufptr[count], "%-20lu ",
 522                                          rlim[i].rlim_max);
 523
 524                 if (lnames[i].unit)
 525                         count += sprintf(&bufptr[count], "%-10s\n",
 526                                          lnames[i].unit);
 527                 else
 528                         count += sprintf(&bufptr[count], "\n");
 529         }
 530
 531         return count;
 532 }
 533
 534 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 535 static int proc_pid_syscall(struct task_struct *task, char *buffer)
 536 {
 537         long nr;
 538         unsigned long args[6], sp, pc;
 539
 540         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
 541                 return sprintf(buffer, "running\n");
 542
 543         if (nr < 0)
 544                 return sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
 545
 546         return sprintf(buffer,
 547                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
 548                        nr,
 549                        args[0], args[1], args[2], args[3], args[4], args[5],
 550                        sp, pc);
 551 }
 552 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 553
 554 /************************************************************************/
 555 /*                       Here the fs part begins                        */
 556 /************************************************************************/
 557
 558 /* permission checks */
 559 static int proc_fd_access_allowed(struct inode *inode)
 560 {
 561         struct task_struct *task;
 562         int allowed = 0;
 563         /* Allow access to a task's file descriptors if it is us or we
 564          * may use ptrace attach to the process and find out that
 565          * information.
 566          */
 567         task = get_proc_task(inode);
 568         if (task) {
 569                 allowed = ptrace_may_access(task, PTRACE_MODE_READ);
 570                 put_task_struct(task);
 571         }
 572         return allowed;
 573 }
 574
 575 static int proc_setattr(struct dentry *dentry, struct iattr *attr)
 576 {
 577         int error;
 578         struct inode *inode = dentry->d_inode;
 579
 580         if (attr->ia_valid & ATTR_MODE)
 581                 return -EPERM;
 582
 583         error = inode_change_ok(inode, attr);
 584         if (!error)
 585                 error = inode_setattr(inode, attr);
 586         return error;
 587 }
 588
 589 static const struct inode_operations proc_def_inode_operations = {
 590         .setattr        = proc_setattr,
 591 };
 592
 593 static int mounts_open_common(struct inode *inode, struct file *file,
 594                               const struct seq_operations *op)
 595 {
 596         struct task_struct *task = get_proc_task(inode);
 597         struct nsproxy *nsp;
 598         struct mnt_namespace *ns = NULL;
 599         struct fs_struct *fs = NULL;
 600         struct path root;
 601         struct proc_mounts *p;
 602         int ret = -EINVAL;
 603
 604         if (task) {
 605                 rcu_read_lock();
 606                 nsp = task_nsproxy(task);
 607                 if (nsp) {
 608                         ns = nsp->mnt_ns;
 609                         if (ns)
 610                                 get_mnt_ns(ns);
 611                 }
 612                 rcu_read_unlock();
 613                 if (ns)
 614                         fs = get_fs_struct(task);
 615                 put_task_struct(task);
 616         }
 617
 618         if (!ns)
 619                 goto err;
 620         if (!fs)
 621                 goto err_put_ns;
 622
 623         read_lock(&fs->lock);
 624         root = fs->root;
 625         path_get(&root);
 626         read_unlock(&fs->lock);
 627         put_fs_struct(fs);
 628
 629         ret = -ENOMEM;
 630         p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
 631         if (!p)
 632                 goto err_put_path;
 633
 634         file->private_data = &p->m;
 635         ret = seq_open(file, op);
 636         if (ret)
 637                 goto err_free;
 638
 639         p->m.private = p;
 640         p->ns = ns;
 641         p->root = root;
 642         p->event = ns->event;
 643
 644         return 0;
 645
 646  err_free:
 647         kfree(p);
 648  err_put_path:
 649         path_put(&root);
 650  err_put_ns:
 651         put_mnt_ns(ns);
 652  err:
 653         return ret;
 654 }
 655
 656 static int mounts_release(struct inode *inode, struct file *file)
 657 {
 658         struct proc_mounts *p = file->private_data;
 659         path_put(&p->root);
 660         put_mnt_ns(p->ns);
 661         return seq_release(inode, file);
 662 }
 663
 664 static unsigned mounts_poll(struct file *file, poll_table *wait)
 665 {
 666         struct proc_mounts *p = file->private_data;
 667         struct mnt_namespace *ns = p->ns;
 668         unsigned res = 0;
 669
 670         poll_wait(file, &ns->poll, wait);
 671
 672         spin_lock(&vfsmount_lock);
 673         if (p->event != ns->event) {
 674                 p->event = ns->event;
 675                 res = POLLERR;
 676         }
 677         spin_unlock(&vfsmount_lock);
 678
 679         return res;
 680 }
 681
 682 static int mounts_open(struct inode *inode, struct file *file)
 683 {
 684         return mounts_open_common(inode, file, &mounts_op);
 685 }
 686
 687 static const struct file_operations proc_mounts_operations = {
 688         .open           = mounts_open,
 689         .read           = seq_read,
 690         .llseek         = seq_lseek,
 691         .release        = mounts_release,
 692         .poll           = mounts_poll,
 693 };
 694
 695 static int mountinfo_open(struct inode *inode, struct file *file)
 696 {
 697         return mounts_open_common(inode, file, &mountinfo_op);
 698 }
 699
 700 static const struct file_operations proc_mountinfo_operations = {
 701         .open           = mountinfo_open,
 702         .read           = seq_read,
 703         .llseek         = seq_lseek,
 704         .release        = mounts_release,
 705         .poll           = mounts_poll,
 706 };
 707
 708 static int mountstats_open(struct inode *inode, struct file *file)
 709 {
 710         return mounts_open_common(inode, file, &mountstats_op);
 711 }
 712
 713 static const struct file_operations proc_mountstats_operations = {
 714         .open           = mountstats_open,
 715         .read           = seq_read,
 716         .llseek         = seq_lseek,
 717         .release        = mounts_release,
 718 };
 719
 720 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
 721
 722 static ssize_t proc_info_read(struct file * file, char __user * buf,
 723                           size_t count, loff_t *ppos)
 724 {
 725         struct inode * inode = file->f_path.dentry->d_inode;
 726         unsigned long page;
 727         ssize_t length;
 728         struct task_struct *task = get_proc_task(inode);
 729
 730         length = -ESRCH;
 731         if (!task)
 732                 goto out_no_task;
 733
 734         if (count > PROC_BLOCK_SIZE)
 735                 count = PROC_BLOCK_SIZE;
 736
 737         length = -ENOMEM;
 738         if (!(page = __get_free_page(GFP_TEMPORARY)))
 739                 goto out;
 740
 741         length = PROC_I(inode)->op.proc_read(task, (char*)page);
 742
 743         if (length >= 0)
 744                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
 745         free_page(page);
 746 out:
 747         put_task_struct(task);
 748 out_no_task:
 749         return length;
 750 }
 751
 752 static const struct file_operations proc_info_file_operations = {
 753         .read           = proc_info_read,
 754 };
 755
 756 static int proc_single_show(struct seq_file *m, void *v)
 757 {
 758         struct inode *inode = m->private;
 759         struct pid_namespace *ns;
 760         struct pid *pid;
 761         struct task_struct *task;
 762         int ret;
 763
 764         ns = inode->i_sb->s_fs_info;
 765         pid = proc_pid(inode);
 766         task = get_pid_task(pid, PIDTYPE_PID);
 767         if (!task)
 768                 return -ESRCH;
 769
 770         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
 771
 772         put_task_struct(task);
 773         return ret;
 774 }
 775
 776 static int proc_single_open(struct inode *inode, struct file *filp)
 777 {
 778         int ret;
 779         ret = single_open(filp, proc_single_show, NULL);
 780         if (!ret) {
 781                 struct seq_file *m = filp->private_data;
 782
 783                 m->private = inode;
 784         }
 785         return ret;
 786 }
 787
 788 static const struct file_operations proc_single_file_operations = {
 789         .open           = proc_single_open,
 790         .read           = seq_read,
 791         .llseek         = seq_lseek,
 792         .release        = single_release,
 793 };
 794
 795 static int mem_open(struct inode* inode, struct file* file)
 796 {
 797         file->private_data = (void*)((long)current->self_exec_id);
 798         return 0;
 799 }
 800
 801 static ssize_t mem_read(struct file * file, char __user * buf,
 802                         size_t count, loff_t *ppos)
 803 {
 804         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 805         char *page;
 806         unsigned long src = *ppos;
 807         int ret = -ESRCH;
 808         struct mm_struct *mm;
 809
 810         if (!task)
 811                 goto out_no_task;
 812
 813         if (check_mem_permission(task))
 814                 goto out;
 815
 816         ret = -ENOMEM;
 817         page = (char *)__get_free_page(GFP_TEMPORARY);
 818         if (!page)
 819                 goto out;
 820
 821         ret = 0;
 822
 823         mm = get_task_mm(task);
 824         if (!mm)
 825                 goto out_free;
 826
 827         ret = -EIO;
 828
 829         if (file->private_data != (void*)((long)current->self_exec_id))
 830                 goto out_put;
 831
 832         ret = 0;
 833
 834         while (count > 0) {
 835                 int this_len, retval;
 836
 837                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 838                 retval = access_process_vm(task, src, page, this_len, 0);
 839                 if (!retval || check_mem_permission(task)) {
 840                         if (!ret)
 841                                 ret = -EIO;
 842                         break;
 843                 }
 844
 845                 if (copy_to_user(buf, page, retval)) {
 846                         ret = -EFAULT;
 847                         break;
 848                 }
 849
 850                 ret += retval;
 851                 src += retval;
 852                 buf += retval;
 853                 count -= retval;
 854         }
 855         *ppos = src;
 856
 857 out_put:
 858         mmput(mm);
 859 out_free:
 860         free_page((unsigned long) page);
 861 out:
 862         put_task_struct(task);
 863 out_no_task:
 864         return ret;
 865 }
 866
 867 #define mem_write NULL
 868
 869 #ifndef mem_write
 870 /* This is a security hazard */
 871 static ssize_t mem_write(struct file * file, const char __user *buf,
 872                          size_t count, loff_t *ppos)
 873 {
 874         int copied;
 875         char *page;
 876         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
 877         unsigned long dst = *ppos;
 878
 879         copied = -ESRCH;
 880         if (!task)
 881                 goto out_no_task;
 882
 883         if (check_mem_permission(task))
 884                 goto out;
 885
 886         copied = -ENOMEM;
 887         page = (char *)__get_free_page(GFP_TEMPORARY);
 888         if (!page)
 889                 goto out;
 890
 891         copied = 0;
 892         while (count > 0) {
 893                 int this_len, retval;
 894
 895                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 896                 if (copy_from_user(page, buf, this_len)) {
 897                         copied = -EFAULT;
 898                         break;
 899                 }
 900                 retval = access_process_vm(task, dst, page, this_len, 1);
 901                 if (!retval) {
 902                         if (!copied)
 903                                 copied = -EIO;
 904                         break;
 905                 }
 906                 copied += retval;
 907                 buf += retval;
 908                 dst += retval;
 909                 count -= retval;
 910         }
 911         *ppos = dst;
 912         free_page((unsigned long) page);
 913 out:
 914         put_task_struct(task);
 915 out_no_task:
 916         return copied;
 917 }
 918 #endif
 919
 920 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 921 {
 922         switch (orig) {
 923         case 0:
 924                 file->f_pos = offset;
 925                 break;
 926         case 1:
 927                 file->f_pos += offset;
 928                 break;
 929         default:
 930                 return -EINVAL;
 931         }
 932         force_successful_syscall_return();
 933         return file->f_pos;
 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 };
 942
 943 static ssize_t environ_read(struct file *file, char __user *buf,
 944                         size_t count, loff_t *ppos)
 945 {
 946         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
 947         char *page;
 948         unsigned long src = *ppos;
 949         int ret = -ESRCH;
 950         struct mm_struct *mm;
 951
 952         if (!task)
 953                 goto out_no_task;
 954
 955         if (!ptrace_may_access(task, PTRACE_MODE_READ))
 956                 goto out;
 957
 958         ret = -ENOMEM;
 959         page = (char *)__get_free_page(GFP_TEMPORARY);
 960         if (!page)
 961                 goto out;
 962
 963         ret = 0;
 964
 965         mm = get_task_mm(task);
 966         if (!mm)
 967                 goto out_free;
 968
 969         while (count > 0) {
 970                 int this_len, retval, max_len;
 971
 972                 this_len = mm->env_end - (mm->env_start + src);
 973
 974                 if (this_len <= 0)
 975                         break;
 976
 977                 max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 978                 this_len = (this_len > max_len) ? max_len : this_len;
 979
 980                 retval = access_process_vm(task, (mm->env_start + src),
 981                         page, this_len, 0);
 982
 983                 if (retval <= 0) {
 984                         ret = retval;
 985                         break;
 986                 }
 987
 988                 if (copy_to_user(buf, page, retval)) {
 989                         ret = -EFAULT;
 990                         break;
 991                 }
 992
 993                 ret += retval;
 994                 src += retval;
 995                 buf += retval;
 996                 count -= retval;
 997         }
 998         *ppos = src;
 999
1000         mmput(mm);
1001 out_free:
1002         free_page((unsigned long) page);
1003 out:
1004         put_task_struct(task);
1005 out_no_task:
1006         return ret;
1007 }
1008
1009 static const struct file_operations proc_environ_operations = {
1010         .read           = environ_read,
1011 };
1012
1013 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
1014                                 size_t count, loff_t *ppos)
1015 {
1016         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1017         char buffer[PROC_NUMBUF];
1018         size_t len;
1019         int oom_adjust;
1020
1021         if (!task)
1022                 return -ESRCH;
1023         oom_adjust = task->oomkilladj;
1024         put_task_struct(task);
1025
1026         len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
1027
1028         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1029 }
1030
1031 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
1032                                 size_t count, loff_t *ppos)
1033 {
1034         struct task_struct *task;
1035         char buffer[PROC_NUMBUF], *end;
1036         int oom_adjust;
1037
1038         memset(buffer, 0, sizeof(buffer));
1039         if (count > sizeof(buffer) - 1)
1040                 count = sizeof(buffer) - 1;
1041         if (copy_from_user(buffer, buf, count))
1042                 return -EFAULT;
1043         oom_adjust = simple_strtol(buffer, &end, 0);
1044         if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
1045              oom_adjust != OOM_DISABLE)
1046                 return -EINVAL;
1047         if (*end == '\n')
1048                 end++;
1049         task = get_proc_task(file->f_path.dentry->d_inode);
1050         if (!task)
1051                 return -ESRCH;
1052         if (oom_adjust < task->oomkilladj && !capable(CAP_SYS_RESOURCE)) {
1053                 put_task_struct(task);
1054                 return -EACCES;
1055         }
1056         task->oomkilladj = oom_adjust;
1057         put_task_struct(task);
1058         if (end - buffer == 0)
1059                 return -EIO;
1060         return end - buffer;
1061 }
1062
1063 static const struct file_operations proc_oom_adjust_operations = {
1064         .read           = oom_adjust_read,
1065         .write          = oom_adjust_write,
1066 };
1067
1068 #ifdef CONFIG_AUDITSYSCALL
1069 #define TMPBUFLEN 21
1070 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1071                                   size_t count, loff_t *ppos)
1072 {
1073         struct inode * inode = file->f_path.dentry->d_inode;
1074         struct task_struct *task = get_proc_task(inode);
1075         ssize_t length;
1076         char tmpbuf[TMPBUFLEN];
1077
1078         if (!task)
1079                 return -ESRCH;
1080         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1081                                 audit_get_loginuid(task));
1082         put_task_struct(task);
1083         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1084 }
1085
1086 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1087                                    size_t count, loff_t *ppos)
1088 {
1089         struct inode * inode = file->f_path.dentry->d_inode;
1090         char *page, *tmp;
1091         ssize_t length;
1092         uid_t loginuid;
1093
1094         if (!capable(CAP_AUDIT_CONTROL))
1095                 return -EPERM;
1096
1097         if (current != pid_task(proc_pid(inode), PIDTYPE_PID))
1098                 return -EPERM;
1099
1100         if (count >= PAGE_SIZE)
1101                 count = PAGE_SIZE - 1;
1102
1103         if (*ppos != 0) {
1104                 /* No partial writes. */
1105                 return -EINVAL;
1106         }
1107         page = (char*)__get_free_page(GFP_TEMPORARY);
1108         if (!page)
1109                 return -ENOMEM;
1110         length = -EFAULT;
1111         if (copy_from_user(page, buf, count))
1112                 goto out_free_page;
1113
1114         page[count] = '\0';
1115         loginuid = simple_strtoul(page, &tmp, 10);
1116         if (tmp == page) {
1117                 length = -EINVAL;
1118                 goto out_free_page;
1119
1120         }
1121         length = audit_set_loginuid(current, loginuid);
1122         if (likely(length == 0))
1123                 length = count;
1124
1125 out_free_page:
1126         free_page((unsigned long) page);
1127         return length;
1128 }
1129
1130 static const struct file_operations proc_loginuid_operations = {
1131         .read           = proc_loginuid_read,
1132         .write          = proc_loginuid_write,
1133 };
1134
1135 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1136                                   size_t count, loff_t *ppos)
1137 {
1138         struct inode * inode = file->f_path.dentry->d_inode;
1139         struct task_struct *task = get_proc_task(inode);
1140         ssize_t length;
1141         char tmpbuf[TMPBUFLEN];
1142
1143         if (!task)
1144                 return -ESRCH;
1145         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1146                                 audit_get_sessionid(task));
1147         put_task_struct(task);
1148         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1149 }
1150
1151 static const struct file_operations proc_sessionid_operations = {
1152         .read           = proc_sessionid_read,
1153 };
1154 #endif
1155
1156 #ifdef CONFIG_FAULT_INJECTION
1157 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1158                                       size_t count, loff_t *ppos)
1159 {
1160         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1161         char buffer[PROC_NUMBUF];
1162         size_t len;
1163         int make_it_fail;
1164
1165         if (!task)
1166                 return -ESRCH;
1167         make_it_fail = task->make_it_fail;
1168         put_task_struct(task);
1169
1170         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1171
1172         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1173 }
1174
1175 static ssize_t proc_fault_inject_write(struct file * file,
1176                         const char __user * buf, size_t count, loff_t *ppos)
1177 {
1178         struct task_struct *task;
1179         char buffer[PROC_NUMBUF], *end;
1180         int make_it_fail;
1181
1182         if (!capable(CAP_SYS_RESOURCE))
1183                 return -EPERM;
1184         memset(buffer, 0, sizeof(buffer));
1185         if (count > sizeof(buffer) - 1)
1186                 count = sizeof(buffer) - 1;
1187         if (copy_from_user(buffer, buf, count))
1188                 return -EFAULT;
1189         make_it_fail = simple_strtol(buffer, &end, 0);
1190         if (*end == '\n')
1191                 end++;
1192         task = get_proc_task(file->f_dentry->d_inode);
1193         if (!task)
1194                 return -ESRCH;
1195         task->make_it_fail = make_it_fail;
1196         put_task_struct(task);
1197         if (end - buffer == 0)
1198                 return -EIO;
1199         return end - buffer;
1200 }
1201
1202 static const struct file_operations proc_fault_inject_operations = {
1203         .read           = proc_fault_inject_read,
1204         .write          = proc_fault_inject_write,
1205 };
1206 #endif
1207
1208
1209 #ifdef CONFIG_SCHED_DEBUG
1210 /*
1211  * Print out various scheduling related per-task fields:
1212  */
1213 static int sched_show(struct seq_file *m, void *v)
1214 {
1215         struct inode *inode = m->private;
1216         struct task_struct *p;
1217
1218         p = get_proc_task(inode);
1219         if (!p)
1220                 return -ESRCH;
1221         proc_sched_show_task(p, m);
1222
1223         put_task_struct(p);
1224
1225         return 0;
1226 }
1227
1228 static ssize_t
1229 sched_write(struct file *file, const char __user *buf,
1230             size_t count, loff_t *offset)
1231 {
1232         struct inode *inode = file->f_path.dentry->d_inode;
1233         struct task_struct *p;
1234
1235         p = get_proc_task(inode);
1236         if (!p)
1237                 return -ESRCH;
1238         proc_sched_set_task(p);
1239
1240         put_task_struct(p);
1241
1242         return count;
1243 }
1244
1245 static int sched_open(struct inode *inode, struct file *filp)
1246 {
1247         int ret;
1248
1249         ret = single_open(filp, sched_show, NULL);
1250         if (!ret) {
1251                 struct seq_file *m = filp->private_data;
1252
1253                 m->private = inode;
1254         }
1255         return ret;
1256 }
1257
1258 static const struct file_operations proc_pid_sched_operations = {
1259         .open           = sched_open,
1260         .read           = seq_read,
1261         .write          = sched_write,
1262         .llseek         = seq_lseek,
1263         .release        = single_release,
1264 };
1265
1266 #endif
1267
1268 /*
1269  * We added or removed a vma mapping the executable. The vmas are only mapped
1270  * during exec and are not mapped with the mmap system call.
1271  * Callers must hold down_write() on the mm's mmap_sem for these
1272  */
1273 void added_exe_file_vma(struct mm_struct *mm)
1274 {
1275         mm->num_exe_file_vmas++;
1276 }
1277
1278 void removed_exe_file_vma(struct mm_struct *mm)
1279 {
1280         mm->num_exe_file_vmas--;
1281         if ((mm->num_exe_file_vmas == 0) && mm->exe_file){
1282                 fput(mm->exe_file);
1283                 mm->exe_file = NULL;
1284         }
1285
1286 }
1287
1288 void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
1289 {
1290         if (new_exe_file)
1291                 get_file(new_exe_file);
1292         if (mm->exe_file)
1293                 fput(mm->exe_file);
1294         mm->exe_file = new_exe_file;
1295         mm->num_exe_file_vmas = 0;
1296 }
1297
1298 struct file *get_mm_exe_file(struct mm_struct *mm)
1299 {
1300         struct file *exe_file;
1301
1302         /* We need mmap_sem to protect against races with removal of
1303          * VM_EXECUTABLE vmas */
1304         down_read(&mm->mmap_sem);
1305         exe_file = mm->exe_file;
1306         if (exe_file)
1307                 get_file(exe_file);
1308         up_read(&mm->mmap_sem);
1309         return exe_file;
1310 }
1311
1312 void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm)
1313 {
1314         /* It's safe to write the exe_file pointer without exe_file_lock because
1315          * this is called during fork when the task is not yet in /proc */
1316         newmm->exe_file = get_mm_exe_file(oldmm);
1317 }
1318
1319 static int proc_exe_link(struct inode *inode, struct path *exe_path)
1320 {
1321         struct task_struct *task;
1322         struct mm_struct *mm;
1323         struct file *exe_file;
1324
1325         task = get_proc_task(inode);
1326         if (!task)
1327                 return -ENOENT;
1328         mm = get_task_mm(task);
1329         put_task_struct(task);
1330         if (!mm)
1331                 return -ENOENT;
1332         exe_file = get_mm_exe_file(mm);
1333         mmput(mm);
1334         if (exe_file) {
1335                 *exe_path = exe_file->f_path;
1336                 path_get(&exe_file->f_path);
1337                 fput(exe_file);
1338                 return 0;
1339         } else
1340                 return -ENOENT;
1341 }
1342
1343 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1344 {
1345         struct inode *inode = dentry->d_inode;
1346         int error = -EACCES;
1347
1348         /* We don't need a base pointer in the /proc filesystem */
1349         path_put(&nd->path);
1350
1351         /* Are we allowed to snoop on the tasks file descriptors? */
1352         if (!proc_fd_access_allowed(inode))
1353                 goto out;
1354
1355         error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1356         nd->last_type = LAST_BIND;
1357 out:
1358         return ERR_PTR(error);
1359 }
1360
1361 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1362 {
1363         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1364         char *pathname;
1365         int len;
1366
1367         if (!tmp)
1368                 return -ENOMEM;
1369
1370         pathname = d_path(path, tmp, PAGE_SIZE);
1371         len = PTR_ERR(pathname);
1372         if (IS_ERR(pathname))
1373                 goto out;
1374         len = tmp + PAGE_SIZE - 1 - pathname;
1375
1376         if (len > buflen)
1377                 len = buflen;
1378         if (copy_to_user(buffer, pathname, len))
1379                 len = -EFAULT;
1380  out:
1381         free_page((unsigned long)tmp);
1382         return len;
1383 }
1384
1385 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1386 {
1387         int error = -EACCES;
1388         struct inode *inode = dentry->d_inode;
1389         struct path path;
1390
1391         /* Are we allowed to snoop on the tasks file descriptors? */
1392         if (!proc_fd_access_allowed(inode))
1393                 goto out;
1394
1395         error = PROC_I(inode)->op.proc_get_link(inode, &path);
1396         if (error)
1397                 goto out;
1398
1399         error = do_proc_readlink(&path, buffer, buflen);
1400         path_put(&path);
1401 out:
1402         return error;
1403 }
1404
1405 static const struct inode_operations proc_pid_link_inode_operations = {
1406         .readlink       = proc_pid_readlink,
1407         .follow_link    = proc_pid_follow_link,
1408         .setattr        = proc_setattr,
1409 };
1410
1411
1412 /* building an inode */
1413
1414 static int task_dumpable(struct task_struct *task)
1415 {
1416         int dumpable = 0;
1417         struct mm_struct *mm;
1418
1419         task_lock(task);
1420         mm = task->mm;
1421         if (mm)
1422                 dumpable = get_dumpable(mm);
1423         task_unlock(task);
1424         if(dumpable == 1)
1425                 return 1;
1426         return 0;
1427 }
1428
1429
1430 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1431 {
1432         struct inode * inode;
1433         struct proc_inode *ei;
1434         const struct cred *cred;
1435
1436         /* We need a new inode */
1437
1438         inode = new_inode(sb);
1439         if (!inode)
1440                 goto out;
1441
1442         /* Common stuff */
1443         ei = PROC_I(inode);
1444         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1445         inode->i_op = &proc_def_inode_operations;
1446
1447         /*
1448          * grab the reference to task.
1449          */
1450         ei->pid = get_task_pid(task, PIDTYPE_PID);
1451         if (!ei->pid)
1452                 goto out_unlock;
1453
1454         inode->i_uid = 0;
1455         inode->i_gid = 0;
1456         if (task_dumpable(task)) {
1457                 rcu_read_lock();
1458                 cred = __task_cred(task);
1459                 inode->i_uid = cred->euid;
1460                 inode->i_gid = cred->egid;
1461                 rcu_read_unlock();
1462         }
1463         security_task_to_inode(task, inode);
1464
1465 out:
1466         return inode;
1467
1468 out_unlock:
1469         iput(inode);
1470         return NULL;
1471 }
1472
1473 static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1474 {
1475         struct inode *inode = dentry->d_inode;
1476         struct task_struct *task;
1477         const struct cred *cred;
1478
1479         generic_fillattr(inode, stat);
1480
1481         rcu_read_lock();
1482         stat->uid = 0;
1483         stat->gid = 0;
1484         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1485         if (task) {
1486                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1487                     task_dumpable(task)) {
1488                         cred = __task_cred(task);
1489                         stat->uid = cred->euid;
1490                         stat->gid = cred->egid;
1491                 }
1492         }
1493         rcu_read_unlock();
1494         return 0;
1495 }
1496
1497 /* dentry stuff */
1498
1499 /*
1500  *      Exceptional case: normally we are not allowed to unhash a busy
1501  * directory. In this case, however, we can do it - no aliasing problems
1502  * due to the way we treat inodes.
1503  *
1504  * Rewrite the inode's ownerships here because the owning task may have
1505  * performed a setuid(), etc.
1506  *
1507  * Before the /proc/pid/status file was created the only way to read
1508  * the effective uid of a /process was to stat /proc/pid.  Reading
1509  * /proc/pid/status is slow enough that procps and other packages
1510  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1511  * made this apply to all per process world readable and executable
1512  * directories.
1513  */
1514 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1515 {
1516         struct inode *inode = dentry->d_inode;
1517         struct task_struct *task = get_proc_task(inode);
1518         const struct cred *cred;
1519
1520         if (task) {
1521                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1522                     task_dumpable(task)) {
1523                         rcu_read_lock();
1524                         cred = __task_cred(task);
1525                         inode->i_uid = cred->euid;
1526                         inode->i_gid = cred->egid;
1527                         rcu_read_unlock();
1528                 } else {
1529                         inode->i_uid = 0;
1530                         inode->i_gid = 0;
1531                 }
1532                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1533                 security_task_to_inode(task, inode);
1534                 put_task_struct(task);
1535                 return 1;
1536         }
1537         d_drop(dentry);
1538         return 0;
1539 }
1540
1541 static int pid_delete_dentry(struct dentry * dentry)
1542 {
1543         /* Is the task we represent dead?
1544          * If so, then don't put the dentry on the lru list,
1545          * kill it immediately.
1546          */
1547         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1548 }
1549
1550 static struct dentry_operations pid_dentry_operations =
1551 {
1552         .d_revalidate   = pid_revalidate,
1553         .d_delete       = pid_delete_dentry,
1554 };
1555
1556 /* Lookups */
1557
1558 typedef struct dentry *instantiate_t(struct inode *, struct dentry *,
1559                                 struct task_struct *, const void *);
1560
1561 /*
1562  * Fill a directory entry.
1563  *
1564  * If possible create the dcache entry and derive our inode number and
1565  * file type from dcache entry.
1566  *
1567  * Since all of the proc inode numbers are dynamically generated, the inode
1568  * numbers do not exist until the inode is cache.  This means creating the
1569  * the dcache entry in readdir is necessary to keep the inode numbers
1570  * reported by readdir in sync with the inode numbers reported
1571  * by stat.
1572  */
1573 static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1574         char *name, int len,
1575         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1576 {
1577         struct dentry *child, *dir = filp->f_path.dentry;
1578         struct inode *inode;
1579         struct qstr qname;
1580         ino_t ino = 0;
1581         unsigned type = DT_UNKNOWN;
1582
1583         qname.name = name;
1584         qname.len  = len;
1585         qname.hash = full_name_hash(name, len);
1586
1587         child = d_lookup(dir, &qname);
1588         if (!child) {
1589                 struct dentry *new;
1590                 new = d_alloc(dir, &qname);
1591                 if (new) {
1592                         child = instantiate(dir->d_inode, new, task, ptr);
1593                         if (child)
1594                                 dput(new);
1595                         else
1596                                 child = new;
1597                 }
1598         }
1599         if (!child || IS_ERR(child) || !child->d_inode)
1600                 goto end_instantiate;
1601         inode = child->d_inode;
1602         if (inode) {
1603                 ino = inode->i_ino;
1604                 type = inode->i_mode >> 12;
1605         }
1606         dput(child);
1607 end_instantiate:
1608         if (!ino)
1609                 ino = find_inode_number(dir, &qname);
1610         if (!ino)
1611                 ino = 1;
1612         return filldir(dirent, name, len, filp->f_pos, ino, type);
1613 }
1614
1615 static unsigned name_to_int(struct dentry *dentry)
1616 {
1617         const char *name = dentry->d_name.name;
1618         int len = dentry->d_name.len;
1619         unsigned n = 0;
1620
1621         if (len > 1 && *name == '0')
1622                 goto out;
1623         while (len-- > 0) {
1624                 unsigned c = *name++ - '0';
1625                 if (c > 9)
1626                         goto out;
1627                 if (n >= (~0U-9)/10)
1628                         goto out;
1629                 n *= 10;
1630                 n += c;
1631         }
1632         return n;
1633 out:
1634         return ~0U;
1635 }
1636
1637 #define PROC_FDINFO_MAX 64
1638
1639 static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1640 {
1641         struct task_struct *task = get_proc_task(inode);
1642         struct files_struct *files = NULL;
1643         struct file *file;
1644         int fd = proc_fd(inode);
1645
1646         if (task) {
1647                 files = get_files_struct(task);
1648                 put_task_struct(task);
1649         }
1650         if (files) {
1651                 /*
1652                  * We are not taking a ref to the file structure, so we must
1653                  * hold ->file_lock.
1654                  */
1655                 spin_lock(&files->file_lock);
1656                 file = fcheck_files(files, fd);
1657                 if (file) {
1658                         if (path) {
1659                                 *path = file->f_path;
1660                                 path_get(&file->f_path);
1661                         }
1662                         if (info)
1663                                 snprintf(info, PROC_FDINFO_MAX,
1664                                          "pos:\t%lli\n"
1665                                          "flags:\t0%o\n",
1666                                          (long long) file->f_pos,
1667                                          file->f_flags);
1668                         spin_unlock(&files->file_lock);
1669                         put_files_struct(files);
1670                         return 0;
1671                 }
1672                 spin_unlock(&files->file_lock);
1673                 put_files_struct(files);
1674         }
1675         return -ENOENT;
1676 }
1677
1678 static int proc_fd_link(struct inode *inode, struct path *path)
1679 {
1680         return proc_fd_info(inode, path, NULL);
1681 }
1682
1683 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1684 {
1685         struct inode *inode = dentry->d_inode;
1686         struct task_struct *task = get_proc_task(inode);
1687         int fd = proc_fd(inode);
1688         struct files_struct *files;
1689         const struct cred *cred;
1690
1691         if (task) {
1692                 files = get_files_struct(task);
1693                 if (files) {
1694                         rcu_read_lock();
1695                         if (fcheck_files(files, fd)) {
1696                                 rcu_read_unlock();
1697                                 put_files_struct(files);
1698                                 if (task_dumpable(task)) {
1699                                         rcu_read_lock();
1700                                         cred = __task_cred(task);
1701                                         inode->i_uid = cred->euid;
1702                                         inode->i_gid = cred->egid;
1703                                         rcu_read_unlock();
1704                                 } else {
1705                                         inode->i_uid = 0;
1706                                         inode->i_gid = 0;
1707                                 }
1708                                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1709                                 security_task_to_inode(task, inode);
1710                                 put_task_struct(task);
1711                                 return 1;
1712                         }
1713                         rcu_read_unlock();
1714                         put_files_struct(files);
1715                 }
1716                 put_task_struct(task);
1717         }
1718         d_drop(dentry);
1719         return 0;
1720 }
1721
1722 static struct dentry_operations tid_fd_dentry_operations =
1723 {
1724         .d_revalidate   = tid_fd_revalidate,
1725         .d_delete       = pid_delete_dentry,
1726 };
1727
1728 static struct dentry *proc_fd_instantiate(struct inode *dir,
1729         struct dentry *dentry, struct task_struct *task, const void *ptr)
1730 {
1731         unsigned fd = *(const unsigned *)ptr;
1732         struct file *file;
1733         struct files_struct *files;
1734         struct inode *inode;
1735         struct proc_inode *ei;
1736         struct dentry *error = ERR_PTR(-ENOENT);
1737
1738         inode = proc_pid_make_inode(dir->i_sb, task);
1739         if (!inode)
1740                 goto out;
1741         ei = PROC_I(inode);
1742         ei->fd = fd;
1743         files = get_files_struct(task);
1744         if (!files)
1745                 goto out_iput;
1746         inode->i_mode = S_IFLNK;
1747
1748         /*
1749          * We are not taking a ref to the file structure, so we must
1750          * hold ->file_lock.
1751          */
1752         spin_lock(&files->file_lock);
1753         file = fcheck_files(files, fd);
1754         if (!file)
1755                 goto out_unlock;
1756         if (file->f_mode & FMODE_READ)
1757                 inode->i_mode |= S_IRUSR | S_IXUSR;
1758         if (file->f_mode & FMODE_WRITE)
1759                 inode->i_mode |= S_IWUSR | S_IXUSR;
1760         spin_unlock(&files->file_lock);
1761         put_files_struct(files);
1762
1763         inode->i_op = &proc_pid_link_inode_operations;
1764         inode->i_size = 64;
1765         ei->op.proc_get_link = proc_fd_link;
1766         dentry->d_op = &tid_fd_dentry_operations;
1767         d_add(dentry, inode);
1768         /* Close the race of the process dying before we return the dentry */
1769         if (tid_fd_revalidate(dentry, NULL))
1770                 error = NULL;
1771
1772  out:
1773         return error;
1774 out_unlock:
1775         spin_unlock(&files->file_lock);
1776         put_files_struct(files);
1777 out_iput:
1778         iput(inode);
1779         goto out;
1780 }
1781
1782 static struct dentry *proc_lookupfd_common(struct inode *dir,
1783                                            struct dentry *dentry,
1784                                            instantiate_t instantiate)
1785 {
1786         struct task_struct *task = get_proc_task(dir);
1787         unsigned fd = name_to_int(dentry);
1788         struct dentry *result = ERR_PTR(-ENOENT);
1789
1790         if (!task)
1791                 goto out_no_task;
1792         if (fd == ~0U)
1793                 goto out;
1794
1795         result = instantiate(dir, dentry, task, &fd);
1796 out:
1797         put_task_struct(task);
1798 out_no_task:
1799         return result;
1800 }
1801
1802 static int proc_readfd_common(struct file * filp, void * dirent,
1803                               filldir_t filldir, instantiate_t instantiate)
1804 {
1805         struct dentry *dentry = filp->f_path.dentry;
1806         struct inode *inode = dentry->d_inode;
1807         struct task_struct *p = get_proc_task(inode);
1808         unsigned int fd, ino;
1809         int retval;
1810         struct files_struct * files;
1811
1812         retval = -ENOENT;
1813         if (!p)
1814                 goto out_no_task;
1815         retval = 0;
1816
1817         fd = filp->f_pos;
1818         switch (fd) {
1819                 case 0:
1820                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1821                                 goto out;
1822                         filp->f_pos++;
1823                 case 1:
1824                         ino = parent_ino(dentry);
1825                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1826                                 goto out;
1827                         filp->f_pos++;
1828                 default:
1829                         files = get_files_struct(p);
1830                         if (!files)
1831                                 goto out;
1832                         rcu_read_lock();
1833                         for (fd = filp->f_pos-2;
1834                              fd < files_fdtable(files)->max_fds;
1835                              fd++, filp->f_pos++) {
1836                                 char name[PROC_NUMBUF];
1837                                 int len;
1838
1839                                 if (!fcheck_files(files, fd))
1840                                         continue;
1841                                 rcu_read_unlock();
1842
1843                                 len = snprintf(name, sizeof(name), "%d", fd);
1844                                 if (proc_fill_cache(filp, dirent, filldir,
1845                                                     name, len, instantiate,
1846                                                     p, &fd) < 0) {
1847                                         rcu_read_lock();
1848                                         break;
1849                                 }
1850                                 rcu_read_lock();
1851                         }
1852                         rcu_read_unlock();
1853                         put_files_struct(files);
1854         }
1855 out:
1856         put_task_struct(p);
1857 out_no_task:
1858         return retval;
1859 }
1860
1861 static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
1862                                     struct nameidata *nd)
1863 {
1864         return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
1865 }
1866
1867 static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
1868 {
1869         return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
1870 }
1871
1872 static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
1873                                       size_t len, loff_t *ppos)
1874 {
1875         char tmp[PROC_FDINFO_MAX];
1876         int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
1877         if (!err)
1878                 err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
1879         return err;
1880 }
1881
1882 static const struct file_operations proc_fdinfo_file_operations = {
1883         .open           = nonseekable_open,
1884         .read           = proc_fdinfo_read,
1885 };
1886
1887 static const struct file_operations proc_fd_operations = {
1888         .read           = generic_read_dir,
1889         .readdir        = proc_readfd,
1890 };
1891
1892 /*
1893  * /proc/pid/fd needs a special permission handler so that a process can still
1894  * access /proc/self/fd after it has executed a setuid().
1895  */
1896 static int proc_fd_permission(struct inode *inode, int mask)
1897 {
1898         int rv;
1899
1900         rv = generic_permission(inode, mask, NULL);
1901         if (rv == 0)
1902                 return 0;
1903         if (task_pid(current) == proc_pid(inode))
1904                 rv = 0;
1905         return rv;
1906 }
1907
1908 /*
1909  * proc directories can do almost nothing..
1910  */
1911 static const struct inode_operations proc_fd_inode_operations = {
1912         .lookup         = proc_lookupfd,
1913         .permission     = proc_fd_permission,
1914         .setattr        = proc_setattr,
1915 };
1916
1917 static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
1918         struct dentry *dentry, struct task_struct *task, const void *ptr)
1919 {
1920         unsigned fd = *(unsigned *)ptr;
1921         struct inode *inode;
1922         struct proc_inode *ei;
1923         struct dentry *error = ERR_PTR(-ENOENT);
1924
1925         inode = proc_pid_make_inode(dir->i_sb, task);
1926         if (!inode)
1927                 goto out;
1928         ei = PROC_I(inode);
1929         ei->fd = fd;
1930         inode->i_mode = S_IFREG | S_IRUSR;
1931         inode->i_fop = &proc_fdinfo_file_operations;
1932         dentry->d_op = &tid_fd_dentry_operations;
1933         d_add(dentry, inode);
1934         /* Close the race of the process dying before we return the dentry */
1935         if (tid_fd_revalidate(dentry, NULL))
1936                 error = NULL;
1937
1938  out:
1939         return error;
1940 }
1941
1942 static struct dentry *proc_lookupfdinfo(struct inode *dir,
1943                                         struct dentry *dentry,
1944                                         struct nameidata *nd)
1945 {
1946         return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
1947 }
1948
1949 static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
1950 {
1951         return proc_readfd_common(filp, dirent, filldir,
1952                                   proc_fdinfo_instantiate);
1953 }
1954
1955 static const struct file_operations proc_fdinfo_operations = {
1956         .read           = generic_read_dir,
1957         .readdir        = proc_readfdinfo,
1958 };
1959
1960 /*
1961  * proc directories can do almost nothing..
1962  */
1963 static const struct inode_operations proc_fdinfo_inode_operations = {
1964         .lookup         = proc_lookupfdinfo,
1965         .setattr        = proc_setattr,
1966 };
1967
1968
1969 static struct dentry *proc_pident_instantiate(struct inode *dir,
1970         struct dentry *dentry, struct task_struct *task, const void *ptr)
1971 {
1972         const struct pid_entry *p = ptr;
1973         struct inode *inode;
1974         struct proc_inode *ei;
1975         struct dentry *error = ERR_PTR(-EINVAL);
1976
1977         inode = proc_pid_make_inode(dir->i_sb, task);
1978         if (!inode)
1979                 goto out;
1980
1981         ei = PROC_I(inode);
1982         inode->i_mode = p->mode;
1983         if (S_ISDIR(inode->i_mode))
1984                 inode->i_nlink = 2;     /* Use getattr to fix if necessary */
1985         if (p->iop)
1986                 inode->i_op = p->iop;
1987         if (p->fop)
1988                 inode->i_fop = p->fop;
1989         ei->op = p->op;
1990         dentry->d_op = &pid_dentry_operations;
1991         d_add(dentry, inode);
1992         /* Close the race of the process dying before we return the dentry */
1993         if (pid_revalidate(dentry, NULL))
1994                 error = NULL;
1995 out:
1996         return error;
1997 }
1998
1999 static struct dentry *proc_pident_lookup(struct inode *dir,
2000                                          struct dentry *dentry,
2001                                          const struct pid_entry *ents,
2002                                          unsigned int nents)
2003 {
2004         struct inode *inode;
2005         struct dentry *error;
2006         struct task_struct *task = get_proc_task(dir);
2007         const struct pid_entry *p, *last;
2008
2009         error = ERR_PTR(-ENOENT);
2010         inode = NULL;
2011
2012         if (!task)
2013                 goto out_no_task;
2014
2015         /*
2016          * Yes, it does not scale. And it should not. Don't add
2017          * new entries into /proc/<tgid>/ without very good reasons.
2018          */
2019         last = &ents[nents - 1];
2020         for (p = ents; p <= last; p++) {
2021                 if (p->len != dentry->d_name.len)
2022                         continue;
2023                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2024                         break;
2025         }
2026         if (p > last)
2027                 goto out;
2028
2029         error = proc_pident_instantiate(dir, dentry, task, p);
2030 out:
2031         put_task_struct(task);
2032 out_no_task:
2033         return error;
2034 }
2035
2036 static int proc_pident_fill_cache(struct file *filp, void *dirent,
2037         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2038 {
2039         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2040                                 proc_pident_instantiate, task, p);
2041 }
2042
2043 static int proc_pident_readdir(struct file *filp,
2044                 void *dirent, filldir_t filldir,
2045                 const struct pid_entry *ents, unsigned int nents)
2046 {
2047         int i;
2048         struct dentry *dentry = filp->f_path.dentry;
2049         struct inode *inode = dentry->d_inode;
2050         struct task_struct *task = get_proc_task(inode);
2051         const struct pid_entry *p, *last;
2052         ino_t ino;
2053         int ret;
2054
2055         ret = -ENOENT;
2056         if (!task)
2057                 goto out_no_task;
2058
2059         ret = 0;
2060         i = filp->f_pos;
2061         switch (i) {
2062         case 0:
2063                 ino = inode->i_ino;
2064                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2065                         goto out;
2066                 i++;
2067                 filp->f_pos++;
2068                 /* fall through */
2069         case 1:
2070                 ino = parent_ino(dentry);
2071                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2072                         goto out;
2073                 i++;
2074                 filp->f_pos++;
2075                 /* fall through */
2076         default:
2077                 i -= 2;
2078                 if (i >= nents) {
2079                         ret = 1;
2080                         goto out;
2081                 }
2082                 p = ents + i;
2083                 last = &ents[nents - 1];
2084                 while (p <= last) {
2085                         if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2086                                 goto out;
2087                         filp->f_pos++;
2088                         p++;
2089                 }
2090         }
2091
2092         ret = 1;
2093 out:
2094         put_task_struct(task);
2095 out_no_task:
2096         return ret;
2097 }
2098
2099 #ifdef CONFIG_SECURITY
2100 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2101                                   size_t count, loff_t *ppos)
2102 {
2103         struct inode * inode = file->f_path.dentry->d_inode;
2104         char *p = NULL;
2105         ssize_t length;
2106         struct task_struct *task = get_proc_task(inode);
2107
2108         if (!task)
2109                 return -ESRCH;
2110
2111         length = security_getprocattr(task,
2112                                       (char*)file->f_path.dentry->d_name.name,
2113                                       &p);
2114         put_task_struct(task);
2115         if (length > 0)
2116                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2117         kfree(p);
2118         return length;
2119 }
2120
2121 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2122                                    size_t count, loff_t *ppos)
2123 {
2124         struct inode * inode = file->f_path.dentry->d_inode;
2125         char *page;
2126         ssize_t length;
2127         struct task_struct *task = get_proc_task(inode);
2128
2129         length = -ESRCH;
2130         if (!task)
2131                 goto out_no_task;
2132         if (count > PAGE_SIZE)
2133                 count = PAGE_SIZE;
2134
2135         /* No partial writes. */
2136         length = -EINVAL;
2137         if (*ppos != 0)
2138                 goto out;
2139
2140         length = -ENOMEM;
2141         page = (char*)__get_free_page(GFP_TEMPORARY);
2142         if (!page)
2143                 goto out;
2144
2145         length = -EFAULT;
2146         if (copy_from_user(page, buf, count))
2147                 goto out_free;
2148
2149         length = security_setprocattr(task,
2150                                       (char*)file->f_path.dentry->d_name.name,
2151                                       (void*)page, count);
2152 out_free:
2153         free_page((unsigned long) page);
2154 out:
2155         put_task_struct(task);
2156 out_no_task:
2157         return length;
2158 }
2159
2160 static const struct file_operations proc_pid_attr_operations = {
2161         .read           = proc_pid_attr_read,
2162         .write          = proc_pid_attr_write,
2163 };
2164
2165 static const struct pid_entry attr_dir_stuff[] = {
2166         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2167         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2168         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2169         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2170         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2171         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2172 };
2173
2174 static int proc_attr_dir_readdir(struct file * filp,
2175                              void * dirent, filldir_t filldir)
2176 {
2177         return proc_pident_readdir(filp,dirent,filldir,
2178                                    attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2179 }
2180
2181 static const struct file_operations proc_attr_dir_operations = {
2182         .read           = generic_read_dir,
2183         .readdir        = proc_attr_dir_readdir,
2184 };
2185
2186 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2187                                 struct dentry *dentry, struct nameidata *nd)
2188 {
2189         return proc_pident_lookup(dir, dentry,
2190                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2191 }
2192
2193 static const struct inode_operations proc_attr_dir_inode_operations = {
2194         .lookup         = proc_attr_dir_lookup,
2195         .getattr        = pid_getattr,
2196         .setattr        = proc_setattr,
2197 };
2198
2199 #endif
2200
2201 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
2202 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2203                                          size_t count, loff_t *ppos)
2204 {
2205         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2206         struct mm_struct *mm;
2207         char buffer[PROC_NUMBUF];
2208         size_t len;
2209         int ret;
2210
2211         if (!task)
2212                 return -ESRCH;
2213
2214         ret = 0;
2215         mm = get_task_mm(task);
2216         if (mm) {
2217                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2218                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2219                                 MMF_DUMP_FILTER_SHIFT));
2220                 mmput(mm);
2221                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2222         }
2223
2224         put_task_struct(task);
2225
2226         return ret;
2227 }
2228
2229 static ssize_t proc_coredump_filter_write(struct file *file,
2230                                           const char __user *buf,
2231                                           size_t count,
2232                                           loff_t *ppos)
2233 {
2234         struct task_struct *task;
2235         struct mm_struct *mm;
2236         char buffer[PROC_NUMBUF], *end;
2237         unsigned int val;
2238         int ret;
2239         int i;
2240         unsigned long mask;
2241
2242         ret = -EFAULT;
2243         memset(buffer, 0, sizeof(buffer));
2244         if (count > sizeof(buffer) - 1)
2245                 count = sizeof(buffer) - 1;
2246         if (copy_from_user(buffer, buf, count))
2247                 goto out_no_task;
2248
2249         ret = -EINVAL;
2250         val = (unsigned int)simple_strtoul(buffer, &end, 0);
2251         if (*end == '\n')
2252                 end++;
2253         if (end - buffer == 0)
2254                 goto out_no_task;
2255
2256         ret = -ESRCH;
2257         task = get_proc_task(file->f_dentry->d_inode);
2258         if (!task)
2259                 goto out_no_task;
2260
2261         ret = end - buffer;
2262         mm = get_task_mm(task);
2263         if (!mm)
2264                 goto out_no_mm;
2265
2266         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2267                 if (val & mask)
2268                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2269                 else
2270                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2271         }
2272
2273         mmput(mm);
2274  out_no_mm:
2275         put_task_struct(task);
2276  out_no_task:
2277         return ret;
2278 }
2279
2280 static const struct file_operations proc_coredump_filter_operations = {
2281         .read           = proc_coredump_filter_read,
2282         .write          = proc_coredump_filter_write,
2283 };
2284 #endif
2285
2286 /*
2287  * /proc/self:
2288  */
2289 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2290                               int buflen)
2291 {
2292         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2293         pid_t tgid = task_tgid_nr_ns(current, ns);
2294         char tmp[PROC_NUMBUF];
2295         if (!tgid)
2296                 return -ENOENT;
2297         sprintf(tmp, "%d", tgid);
2298         return vfs_readlink(dentry,buffer,buflen,tmp);
2299 }
2300
2301 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2302 {
2303         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2304         pid_t tgid = task_tgid_nr_ns(current, ns);
2305         char tmp[PROC_NUMBUF];
2306         if (!tgid)
2307                 return ERR_PTR(-ENOENT);
2308         sprintf(tmp, "%d", task_tgid_nr_ns(current, ns));
2309         return ERR_PTR(vfs_follow_link(nd,tmp));
2310 }
2311
2312 static const struct inode_operations proc_self_inode_operations = {
2313         .readlink       = proc_self_readlink,
2314         .follow_link    = proc_self_follow_link,
2315 };
2316
2317 /*
2318  * proc base
2319  *
2320  * These are the directory entries in the root directory of /proc
2321  * that properly belong to the /proc filesystem, as they describe
2322  * describe something that is process related.
2323  */
2324 static const struct pid_entry proc_base_stuff[] = {
2325         NOD("self", S_IFLNK|S_IRWXUGO,
2326                 &proc_self_inode_operations, NULL, {}),
2327 };
2328
2329 /*
2330  *      Exceptional case: normally we are not allowed to unhash a busy
2331  * directory. In this case, however, we can do it - no aliasing problems
2332  * due to the way we treat inodes.
2333  */
2334 static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd)
2335 {
2336         struct inode *inode = dentry->d_inode;
2337         struct task_struct *task = get_proc_task(inode);
2338         if (task) {
2339                 put_task_struct(task);
2340                 return 1;
2341         }
2342         d_drop(dentry);
2343         return 0;
2344 }
2345
2346 static struct dentry_operations proc_base_dentry_operations =
2347 {
2348         .d_revalidate   = proc_base_revalidate,
2349         .d_delete       = pid_delete_dentry,
2350 };
2351
2352 static struct dentry *proc_base_instantiate(struct inode *dir,
2353         struct dentry *dentry, struct task_struct *task, const void *ptr)
2354 {
2355         const struct pid_entry *p = ptr;
2356         struct inode *inode;
2357         struct proc_inode *ei;
2358         struct dentry *error = ERR_PTR(-EINVAL);
2359
2360         /* Allocate the inode */
2361         error = ERR_PTR(-ENOMEM);
2362         inode = new_inode(dir->i_sb);
2363         if (!inode)
2364                 goto out;
2365
2366         /* Initialize the inode */
2367         ei = PROC_I(inode);
2368         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2369
2370         /*
2371          * grab the reference to the task.
2372          */
2373         ei->pid = get_task_pid(task, PIDTYPE_PID);
2374         if (!ei->pid)
2375                 goto out_iput;
2376
2377         inode->i_uid = 0;
2378         inode->i_gid = 0;
2379         inode->i_mode = p->mode;
2380         if (S_ISDIR(inode->i_mode))
2381                 inode->i_nlink = 2;
2382         if (S_ISLNK(inode->i_mode))
2383                 inode->i_size = 64;
2384         if (p->iop)
2385                 inode->i_op = p->iop;
2386         if (p->fop)
2387                 inode->i_fop = p->fop;
2388         ei->op = p->op;
2389         dentry->d_op = &proc_base_dentry_operations;
2390         d_add(dentry, inode);
2391         error = NULL;
2392 out:
2393         return error;
2394 out_iput:
2395         iput(inode);
2396         goto out;
2397 }
2398
2399 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2400 {
2401         struct dentry *error;
2402         struct task_struct *task = get_proc_task(dir);
2403         const struct pid_entry *p, *last;
2404
2405         error = ERR_PTR(-ENOENT);
2406
2407         if (!task)
2408                 goto out_no_task;
2409
2410         /* Lookup the directory entry */
2411         last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2412         for (p = proc_base_stuff; p <= last; p++) {
2413                 if (p->len != dentry->d_name.len)
2414                         continue;
2415                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2416                         break;
2417         }
2418         if (p > last)
2419                 goto out;
2420
2421         error = proc_base_instantiate(dir, dentry, task, p);
2422
2423 out:
2424         put_task_struct(task);
2425 out_no_task:
2426         return error;
2427 }
2428
2429 static int proc_base_fill_cache(struct file *filp, void *dirent,
2430         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2431 {
2432         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2433                                 proc_base_instantiate, task, p);
2434 }
2435
2436 #ifdef CONFIG_TASK_IO_ACCOUNTING
2437 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2438 {
2439         struct task_io_accounting acct = task->ioac;
2440         unsigned long flags;
2441
2442         if (whole && lock_task_sighand(task, &flags)) {
2443                 struct task_struct *t = task;
2444
2445                 task_io_accounting_add(&acct, &task->signal->ioac);
2446                 while_each_thread(task, t)
2447                         task_io_accounting_add(&acct, &t->ioac);
2448
2449                 unlock_task_sighand(task, &flags);
2450         }
2451         return sprintf(buffer,
2452                         "rchar: %llu\n"
2453                         "wchar: %llu\n"
2454                         "syscr: %llu\n"
2455                         "syscw: %llu\n"
2456                         "read_bytes: %llu\n"
2457                         "write_bytes: %llu\n"
2458                         "cancelled_write_bytes: %llu\n",
2459                         (unsigned long long)acct.rchar,
2460                         (unsigned long long)acct.wchar,
2461                         (unsigned long long)acct.syscr,
2462                         (unsigned long long)acct.syscw,
2463                         (unsigned long long)acct.read_bytes,
2464                         (unsigned long long)acct.write_bytes,
2465                         (unsigned long long)acct.cancelled_write_bytes);
2466 }
2467
2468 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2469 {
2470         return do_io_accounting(task, buffer, 0);
2471 }
2472
2473 static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2474 {
2475         return do_io_accounting(task, buffer, 1);
2476 }
2477 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2478
2479 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2480                                 struct pid *pid, struct task_struct *task)
2481 {
2482         seq_printf(m, "%08x\n", task->personality);
2483         return 0;
2484 }
2485
2486 /*
2487  * Thread groups
2488  */
2489 static const struct file_operations proc_task_operations;
2490 static const struct inode_operations proc_task_inode_operations;
2491
2492 static const struct pid_entry tgid_base_stuff[] = {
2493         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2494         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2495         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2496 #ifdef CONFIG_NET
2497         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2498 #endif
2499         REG("environ",    S_IRUSR, proc_environ_operations),
2500         INF("auxv",       S_IRUSR, proc_pid_auxv),
2501         ONE("status",     S_IRUGO, proc_pid_status),
2502         ONE("personality", S_IRUSR, proc_pid_personality),
2503         INF("limits",     S_IRUSR, proc_pid_limits),
2504 #ifdef CONFIG_SCHED_DEBUG
2505         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2506 #endif
2507 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2508         INF("syscall",    S_IRUSR, proc_pid_syscall),
2509 #endif
2510         INF("cmdline",    S_IRUGO, proc_pid_cmdline),
2511         ONE("stat",       S_IRUGO, proc_tgid_stat),
2512         ONE("statm",      S_IRUGO, proc_pid_statm),
2513         REG("maps",       S_IRUGO, proc_maps_operations),
2514 #ifdef CONFIG_NUMA
2515         REG("numa_maps",  S_IRUGO, proc_numa_maps_operations),
2516 #endif
2517         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2518         LNK("cwd",        proc_cwd_link),
2519         LNK("root",       proc_root_link),
2520         LNK("exe",        proc_exe_link),
2521         REG("mounts",     S_IRUGO, proc_mounts_operations),
2522         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2523         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2524 #ifdef CONFIG_PROC_PAGE_MONITOR
2525         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2526         REG("smaps",      S_IRUGO, proc_smaps_operations),
2527         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2528 #endif
2529 #ifdef CONFIG_SECURITY
2530         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2531 #endif
2532 #ifdef CONFIG_KALLSYMS
2533         INF("wchan",      S_IRUGO, proc_pid_wchan),
2534 #endif
2535 #ifdef CONFIG_STACKTRACE
2536         ONE("stack",      S_IRUSR, proc_pid_stack),
2537 #endif
2538 #ifdef CONFIG_SCHEDSTATS
2539         INF("schedstat",  S_IRUGO, proc_pid_schedstat),
2540 #endif
2541 #ifdef CONFIG_LATENCYTOP
2542         REG("latency",  S_IRUGO, proc_lstats_operations),
2543 #endif
2544 #ifdef CONFIG_PROC_PID_CPUSET
2545         REG("cpuset",     S_IRUGO, proc_cpuset_operations),
2546 #endif
2547 #ifdef CONFIG_CGROUPS
2548         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2549 #endif
2550         INF("oom_score",  S_IRUGO, proc_oom_score),
2551         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
2552 #ifdef CONFIG_AUDITSYSCALL
2553         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2554         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2555 #endif
2556 #ifdef CONFIG_FAULT_INJECTION
2557         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2558 #endif
2559 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
2560         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2561 #endif
2562 #ifdef CONFIG_TASK_IO_ACCOUNTING
2563         INF("io",       S_IRUGO, proc_tgid_io_accounting),
2564 #endif
2565 };
2566
2567 static int proc_tgid_base_readdir(struct file * filp,
2568                              void * dirent, filldir_t filldir)
2569 {
2570         return proc_pident_readdir(filp,dirent,filldir,
2571                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2572 }
2573
2574 static const struct file_operations proc_tgid_base_operations = {
2575         .read           = generic_read_dir,
2576         .readdir        = proc_tgid_base_readdir,
2577 };
2578
2579 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2580         return proc_pident_lookup(dir, dentry,
2581                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2582 }
2583
2584 static const struct inode_operations proc_tgid_base_inode_operations = {
2585         .lookup         = proc_tgid_base_lookup,
2586         .getattr        = pid_getattr,
2587         .setattr        = proc_setattr,
2588 };
2589
2590 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2591 {
2592         struct dentry *dentry, *leader, *dir;
2593         char buf[PROC_NUMBUF];
2594         struct qstr name;
2595
2596         name.name = buf;
2597         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2598         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2599         if (dentry) {
2600                 if (!(current->flags & PF_EXITING))
2601                         shrink_dcache_parent(dentry);
2602                 d_drop(dentry);
2603                 dput(dentry);
2604         }
2605
2606         if (tgid == 0)
2607                 goto out;
2608
2609         name.name = buf;
2610         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2611         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2612         if (!leader)
2613                 goto out;
2614
2615         name.name = "task";
2616         name.len = strlen(name.name);
2617         dir = d_hash_and_lookup(leader, &name);
2618         if (!dir)
2619                 goto out_put_leader;
2620
2621         name.name = buf;
2622         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2623         dentry = d_hash_and_lookup(dir, &name);
2624         if (dentry) {
2625                 shrink_dcache_parent(dentry);
2626                 d_drop(dentry);
2627                 dput(dentry);
2628         }
2629
2630         dput(dir);
2631 out_put_leader:
2632         dput(leader);
2633 out:
2634         return;
2635 }
2636
2637 /**
2638  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2639  * @task: task that should be flushed.
2640  *
2641  * When flushing dentries from proc, one needs to flush them from global
2642  * proc (proc_mnt) and from all the namespaces' procs this task was seen
2643  * in. This call is supposed to do all of this job.
2644  *
2645  * Looks in the dcache for
2646  * /proc/@pid
2647  * /proc/@tgid/task/@pid
2648  * if either directory is present flushes it and all of it'ts children
2649  * from the dcache.
2650  *
2651  * It is safe and reasonable to cache /proc entries for a task until
2652  * that task exits.  After that they just clog up the dcache with
2653  * useless entries, possibly causing useful dcache entries to be
2654  * flushed instead.  This routine is proved to flush those useless
2655  * dcache entries at process exit time.
2656  *
2657  * NOTE: This routine is just an optimization so it does not guarantee
2658  *       that no dcache entries will exist at process exit time it
2659  *       just makes it very unlikely that any will persist.
2660  */
2661
2662 void proc_flush_task(struct task_struct *task)
2663 {
2664         int i;
2665         struct pid *pid, *tgid = NULL;
2666         struct upid *upid;
2667
2668         pid = task_pid(task);
2669         if (thread_group_leader(task))
2670                 tgid = task_tgid(task);
2671
2672         for (i = 0; i <= pid->level; i++) {
2673                 upid = &pid->numbers[i];
2674                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2675                         tgid ? tgid->numbers[i].nr : 0);
2676         }
2677
2678         upid = &pid->numbers[pid->level];
2679         if (upid->nr == 1)
2680                 pid_ns_release_proc(upid->ns);
2681 }
2682
2683 static struct dentry *proc_pid_instantiate(struct inode *dir,
2684                                            struct dentry * dentry,
2685                                            struct task_struct *task, const void *ptr)
2686 {
2687         struct dentry *error = ERR_PTR(-ENOENT);
2688         struct inode *inode;
2689
2690         inode = proc_pid_make_inode(dir->i_sb, task);
2691         if (!inode)
2692                 goto out;
2693
2694         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2695         inode->i_op = &proc_tgid_base_inode_operations;
2696         inode->i_fop = &proc_tgid_base_operations;
2697         inode->i_flags|=S_IMMUTABLE;
2698
2699         inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
2700                 ARRAY_SIZE(tgid_base_stuff));
2701
2702         dentry->d_op = &pid_dentry_operations;
2703
2704         d_add(dentry, inode);
2705         /* Close the race of the process dying before we return the dentry */
2706         if (pid_revalidate(dentry, NULL))
2707                 error = NULL;
2708 out:
2709         return error;
2710 }
2711
2712 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2713 {
2714         struct dentry *result = ERR_PTR(-ENOENT);
2715         struct task_struct *task;
2716         unsigned tgid;
2717         struct pid_namespace *ns;
2718
2719         result = proc_base_lookup(dir, dentry);
2720         if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
2721                 goto out;
2722
2723         tgid = name_to_int(dentry);
2724         if (tgid == ~0U)
2725                 goto out;
2726
2727         ns = dentry->d_sb->s_fs_info;
2728         rcu_read_lock();
2729         task = find_task_by_pid_ns(tgid, ns);
2730         if (task)
2731                 get_task_struct(task);
2732         rcu_read_unlock();
2733         if (!task)
2734                 goto out;
2735
2736         result = proc_pid_instantiate(dir, dentry, task, NULL);
2737         put_task_struct(task);
2738 out:
2739         return result;
2740 }
2741
2742 /*
2743  * Find the first task with tgid >= tgid
2744  *
2745  */
2746 struct tgid_iter {
2747         unsigned int tgid;
2748         struct task_struct *task;
2749 };
2750 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
2751 {
2752         struct pid *pid;
2753
2754         if (iter.task)
2755                 put_task_struct(iter.task);
2756         rcu_read_lock();
2757 retry:
2758         iter.task = NULL;
2759         pid = find_ge_pid(iter.tgid, ns);
2760         if (pid) {
2761                 iter.tgid = pid_nr_ns(pid, ns);
2762                 iter.task = pid_task(pid, PIDTYPE_PID);
2763                 /* What we to know is if the pid we have find is the
2764                  * pid of a thread_group_leader.  Testing for task
2765                  * being a thread_group_leader is the obvious thing
2766                  * todo but there is a window when it fails, due to
2767                  * the pid transfer logic in de_thread.
2768                  *
2769                  * So we perform the straight forward test of seeing
2770                  * if the pid we have found is the pid of a thread
2771                  * group leader, and don't worry if the task we have
2772                  * found doesn't happen to be a thread group leader.
2773                  * As we don't care in the case of readdir.
2774                  */
2775                 if (!iter.task || !has_group_leader_pid(iter.task)) {
2776                         iter.tgid += 1;
2777                         goto retry;
2778                 }
2779                 get_task_struct(iter.task);
2780         }
2781         rcu_read_unlock();
2782         return iter;
2783 }
2784
2785 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
2786
2787 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
2788         struct tgid_iter iter)
2789 {
2790         char name[PROC_NUMBUF];
2791         int len = snprintf(name, sizeof(name), "%d", iter.tgid);
2792         return proc_fill_cache(filp, dirent, filldir, name, len,
2793                                 proc_pid_instantiate, iter.task, NULL);
2794 }
2795
2796 /* for the /proc/ directory itself, after non-process stuff has been done */
2797 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2798 {
2799         unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2800         struct task_struct *reaper = get_proc_task(filp->f_path.dentry->d_inode);
2801         struct tgid_iter iter;
2802         struct pid_namespace *ns;
2803
2804         if (!reaper)
2805                 goto out_no_task;
2806
2807         for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
2808                 const struct pid_entry *p = &proc_base_stuff[nr];
2809                 if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
2810                         goto out;
2811         }
2812
2813         ns = filp->f_dentry->d_sb->s_fs_info;
2814         iter.task = NULL;
2815         iter.tgid = filp->f_pos - TGID_OFFSET;
2816         for (iter = next_tgid(ns, iter);
2817              iter.task;
2818              iter.tgid += 1, iter = next_tgid(ns, iter)) {
2819                 filp->f_pos = iter.tgid + TGID_OFFSET;
2820                 if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
2821                         put_task_struct(iter.task);
2822                         goto out;
2823                 }
2824         }
2825         filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
2826 out:
2827         put_task_struct(reaper);
2828 out_no_task:
2829         return 0;
2830 }
2831
2832 /*
2833  * Tasks
2834  */
2835 static const struct pid_entry tid_base_stuff[] = {
2836         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2837         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fd_operations),
2838         REG("environ",   S_IRUSR, proc_environ_operations),
2839         INF("auxv",      S_IRUSR, proc_pid_auxv),
2840         ONE("status",    S_IRUGO, proc_pid_status),
2841         ONE("personality", S_IRUSR, proc_pid_personality),
2842         INF("limits",    S_IRUSR, proc_pid_limits),
2843 #ifdef CONFIG_SCHED_DEBUG
2844         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2845 #endif
2846 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2847         INF("syscall",   S_IRUSR, proc_pid_syscall),
2848 #endif
2849         INF("cmdline",   S_IRUGO, proc_pid_cmdline),
2850         ONE("stat",      S_IRUGO, proc_tid_stat),
2851         ONE("statm",     S_IRUGO, proc_pid_statm),
2852         REG("maps",      S_IRUGO, proc_maps_operations),
2853 #ifdef CONFIG_NUMA
2854         REG("numa_maps", S_IRUGO, proc_numa_maps_operations),
2855 #endif
2856         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
2857         LNK("cwd",       proc_cwd_link),
2858         LNK("root",      proc_root_link),
2859         LNK("exe",       proc_exe_link),
2860         REG("mounts",    S_IRUGO, proc_mounts_operations),
2861         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2862 #ifdef CONFIG_PROC_PAGE_MONITOR
2863         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2864         REG("smaps",     S_IRUGO, proc_smaps_operations),
2865         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2866 #endif
2867 #ifdef CONFIG_SECURITY
2868         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2869 #endif
2870 #ifdef CONFIG_KALLSYMS
2871         INF("wchan",     S_IRUGO, proc_pid_wchan),
2872 #endif
2873 #ifdef CONFIG_STACKTRACE
2874         ONE("stack",      S_IRUSR, proc_pid_stack),
2875 #endif
2876 #ifdef CONFIG_SCHEDSTATS
2877         INF("schedstat", S_IRUGO, proc_pid_schedstat),
2878 #endif
2879 #ifdef CONFIG_LATENCYTOP
2880         REG("latency",  S_IRUGO, proc_lstats_operations),
2881 #endif
2882 #ifdef CONFIG_PROC_PID_CPUSET
2883         REG("cpuset",    S_IRUGO, proc_cpuset_operations),
2884 #endif
2885 #ifdef CONFIG_CGROUPS
2886         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2887 #endif
2888         INF("oom_score", S_IRUGO, proc_oom_score),
2889         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
2890 #ifdef CONFIG_AUDITSYSCALL
2891         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
2892         REG("sessionid",  S_IRUSR, proc_sessionid_operations),
2893 #endif
2894 #ifdef CONFIG_FAULT_INJECTION
2895         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2896 #endif
2897 #ifdef CONFIG_TASK_IO_ACCOUNTING
2898         INF("io",       S_IRUGO, proc_tid_io_accounting),
2899 #endif
2900 };
2901
2902 static int proc_tid_base_readdir(struct file * filp,
2903                              void * dirent, filldir_t filldir)
2904 {
2905         return proc_pident_readdir(filp,dirent,filldir,
2906                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
2907 }
2908
2909 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2910         return proc_pident_lookup(dir, dentry,
2911                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
2912 }
2913
2914 static const struct file_operations proc_tid_base_operations = {
2915         .read           = generic_read_dir,
2916         .readdir        = proc_tid_base_readdir,
2917 };
2918
2919 static const struct inode_operations proc_tid_base_inode_operations = {
2920         .lookup         = proc_tid_base_lookup,
2921         .getattr        = pid_getattr,
2922         .setattr        = proc_setattr,
2923 };
2924
2925 static struct dentry *proc_task_instantiate(struct inode *dir,
2926         struct dentry *dentry, struct task_struct *task, const void *ptr)
2927 {
2928         struct dentry *error = ERR_PTR(-ENOENT);
2929         struct inode *inode;
2930         inode = proc_pid_make_inode(dir->i_sb, task);
2931
2932         if (!inode)
2933                 goto out;
2934         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2935         inode->i_op = &proc_tid_base_inode_operations;
2936         inode->i_fop = &proc_tid_base_operations;
2937         inode->i_flags|=S_IMMUTABLE;
2938
2939         inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
2940                 ARRAY_SIZE(tid_base_stuff));
2941
2942         dentry->d_op = &pid_dentry_operations;
2943
2944         d_add(dentry, inode);
2945         /* Close the race of the process dying before we return the dentry */
2946         if (pid_revalidate(dentry, NULL))
2947                 error = NULL;
2948 out:
2949         return error;
2950 }
2951
2952 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2953 {
2954         struct dentry *result = ERR_PTR(-ENOENT);
2955         struct task_struct *task;
2956         struct task_struct *leader = get_proc_task(dir);
2957         unsigned tid;
2958         struct pid_namespace *ns;
2959
2960         if (!leader)
2961                 goto out_no_task;
2962
2963         tid = name_to_int(dentry);
2964         if (tid == ~0U)
2965                 goto out;
2966
2967         ns = dentry->d_sb->s_fs_info;
2968         rcu_read_lock();
2969         task = find_task_by_pid_ns(tid, ns);
2970         if (task)
2971                 get_task_struct(task);
2972         rcu_read_unlock();
2973         if (!task)
2974                 goto out;
2975         if (!same_thread_group(leader, task))
2976                 goto out_drop_task;
2977
2978         result = proc_task_instantiate(dir, dentry, task, NULL);
2979 out_drop_task:
2980         put_task_struct(task);
2981 out:
2982         put_task_struct(leader);
2983 out_no_task:
2984         return result;
2985 }
2986
2987 /*
2988  * Find the first tid of a thread group to return to user space.
2989  *
2990  * Usually this is just the thread group leader, but if the users
2991  * buffer was too small or there was a seek into the middle of the
2992  * directory we have more work todo.
2993  *
2994  * In the case of a short read we start with find_task_by_pid.
2995  *
2996  * In the case of a seek we start with the leader and walk nr
2997  * threads past it.
2998  */
2999 static struct task_struct *first_tid(struct task_struct *leader,
3000                 int tid, int nr, struct pid_namespace *ns)
3001 {
3002         struct task_struct *pos;
3003
3004         rcu_read_lock();
3005         /* Attempt to start with the pid of a thread */
3006         if (tid && (nr > 0)) {
3007                 pos = find_task_by_pid_ns(tid, ns);
3008                 if (pos && (pos->group_leader == leader))
3009                         goto found;
3010         }
3011
3012         /* If nr exceeds the number of threads there is nothing todo */
3013         pos = NULL;
3014         if (nr && nr >= get_nr_threads(leader))
3015                 goto out;
3016
3017         /* If we haven't found our starting place yet start
3018          * with the leader and walk nr threads forward.
3019          */
3020         for (pos = leader; nr > 0; --nr) {
3021                 pos = next_thread(pos);
3022                 if (pos == leader) {
3023                         pos = NULL;
3024                         goto out;
3025                 }
3026         }
3027 found:
3028         get_task_struct(pos);
3029 out:
3030         rcu_read_unlock();
3031         return pos;
3032 }
3033
3034 /*
3035  * Find the next thread in the thread list.
3036  * Return NULL if there is an error or no next thread.
3037  *
3038  * The reference to the input task_struct is released.
3039  */
3040 static struct task_struct *next_tid(struct task_struct *start)
3041 {
3042         struct task_struct *pos = NULL;
3043         rcu_read_lock();
3044         if (pid_alive(start)) {
3045                 pos = next_thread(start);
3046                 if (thread_group_leader(pos))
3047                         pos = NULL;
3048                 else
3049                         get_task_struct(pos);
3050         }
3051         rcu_read_unlock();
3052         put_task_struct(start);
3053         return pos;
3054 }
3055
3056 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3057         struct task_struct *task, int tid)
3058 {
3059         char name[PROC_NUMBUF];
3060         int len = snprintf(name, sizeof(name), "%d", tid);
3061         return proc_fill_cache(filp, dirent, filldir, name, len,
3062                                 proc_task_instantiate, task, NULL);
3063 }
3064
3065 /* for the /proc/TGID/task/ directories */
3066 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3067 {
3068         struct dentry *dentry = filp->f_path.dentry;
3069         struct inode *inode = dentry->d_inode;
3070         struct task_struct *leader = NULL;
3071         struct task_struct *task;
3072         int retval = -ENOENT;
3073         ino_t ino;
3074         int tid;
3075         unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
3076         struct pid_namespace *ns;
3077
3078         task = get_proc_task(inode);
3079         if (!task)
3080                 goto out_no_task;
3081         rcu_read_lock();
3082         if (pid_alive(task)) {
3083                 leader = task->group_leader;
3084                 get_task_struct(leader);
3085         }
3086         rcu_read_unlock();
3087         put_task_struct(task);
3088         if (!leader)
3089                 goto out_no_task;
3090         retval = 0;
3091
3092         switch (pos) {
3093         case 0:
3094                 ino = inode->i_ino;
3095                 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
3096                         goto out;
3097                 pos++;
3098                 /* fall through */
3099         case 1:
3100                 ino = parent_ino(dentry);
3101                 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
3102                         goto out;
3103                 pos++;
3104                 /* fall through */
3105         }
3106
3107         /* f_version caches the tgid value that the last readdir call couldn't
3108          * return. lseek aka telldir automagically resets f_version to 0.
3109          */
3110         ns = filp->f_dentry->d_sb->s_fs_info;
3111         tid = (int)filp->f_version;
3112         filp->f_version = 0;
3113         for (task = first_tid(leader, tid, pos - 2, ns);
3114              task;
3115              task = next_tid(task), pos++) {
3116                 tid = task_pid_nr_ns(task, ns);
3117                 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3118                         /* returning this tgid failed, save it as the first
3119                          * pid for the next readir call */
3120                         filp->f_version = (u64)tid;
3121                         put_task_struct(task);
3122                         break;
3123                 }
3124         }
3125 out:
3126         filp->f_pos = pos;
3127         put_task_struct(leader);
3128 out_no_task:
3129         return retval;
3130 }
3131
3132 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3133 {
3134         struct inode *inode = dentry->d_inode;
3135         struct task_struct *p = get_proc_task(inode);
3136         generic_fillattr(inode, stat);
3137
3138         if (p) {
3139                 stat->nlink += get_nr_threads(p);
3140                 put_task_struct(p);
3141         }
3142
3143         return 0;
3144 }
3145
3146 static const struct inode_operations proc_task_inode_operations = {
3147         .lookup         = proc_task_lookup,
3148         .getattr        = proc_task_getattr,
3149         .setattr        = proc_setattr,
3150 };
3151
3152 static const struct file_operations proc_task_operations = {
3153         .read           = generic_read_dir,
3154         .readdir        = proc_task_readdir,
3155 };