fs/proc/array.c

   1 /*
   2  *  linux/fs/proc/array.c
   3  *
   4  *  Copyright (C) 1992  by Linus Torvalds
   5  *  based on ideas by Darren Senn
   6  *
   7  * Fixes:
   8  * Michael. K. Johnson: stat,statm extensions.
   9  *                      <johnsonm@stolaf.edu>
  10  *
  11  * Pauline Middelink :  Made cmdline,envline only break at '\0's, to
  12  *                      make sure SET_PROCTITLE works. Also removed
  13  *                      bad '!' which forced address recalculation for
  14  *                      EVERY character on the current page.
  15  *                      <middelin@polyware.iaf.nl>
  16  *
  17  * Danny ter Haar    :  added cpuinfo
  18  *                      <dth@cistron.nl>
  19  *
  20  * Alessandro Rubini :  profile extension.
  21  *                      <rubini@ipvvis.unipv.it>
  22  *
  23  * Jeff Tranter      :  added BogoMips field to cpuinfo
  24  *                      <Jeff_Tranter@Mitel.COM>
  25  *
  26  * Bruno Haible      :  remove 4K limit for the maps file
  27  *                      <haible@ma2s2.mathematik.uni-karlsruhe.de>
  28  *
  29  * Yves Arrouye      :  remove removal of trailing spaces in get_array.
  30  *                      <Yves.Arrouye@marin.fdn.fr>
  31  *
  32  * Jerome Forissier  :  added per-CPU time information to /proc/stat
  33  *                      and /proc/<pid>/cpu extension
  34  *                      <forissier@isia.cma.fr>
  35  *                      - Incorporation and non-SMP safe operation
  36  *                      of forissier patch in 2.1.78 by
  37  *                      Hans Marcus <crowbar@concepts.nl>
  38  *
  39  * aeb@cwi.nl        :  /proc/partitions
  40  *
  41  *
  42  * Alan Cox          :  security fixes.
  43  *                      <alan@lxorguk.ukuu.org.uk>
  44  *
  45  * Al Viro           :  safe handling of mm_struct
  46  *
  47  * Gerhard Wichert   :  added BIGMEM support
  48  * Siemens AG           <Gerhard.Wichert@pdb.siemens.de>
  49  *
  50  * Al Viro & Jeff Garzik :  moved most of the thing into base.c and
  51  *                       :  proc_misc.c. The rest may eventually go into
  52  *                       :  base.c too.
  53  */
  54
  55 #include <linux/types.h>
  56 #include <linux/errno.h>
  57 #include <linux/time.h>
  58 #include <linux/kernel.h>
  59 #include <linux/kernel_stat.h>
  60 #include <linux/tty.h>
  61 #include <linux/string.h>
  62 #include <linux/mman.h>
  63 #include <linux/sched.h>
  64 #include <linux/proc_fs.h>
  65 #include <linux/ioport.h>
  66 #include <linux/uaccess.h>
  67 #include <linux/io.h>
  68 #include <linux/mm.h>
  69 #include <linux/hugetlb.h>
  70 #include <linux/pagemap.h>
  71 #include <linux/swap.h>
  72 #include <linux/smp.h>
  73 #include <linux/signal.h>
  74 #include <linux/highmem.h>
  75 #include <linux/file.h>
  76 #include <linux/fdtable.h>
  77 #include <linux/times.h>
  78 #include <linux/cpuset.h>
  79 #include <linux/rcupdate.h>
  80 #include <linux/delayacct.h>
  81 #include <linux/seq_file.h>
  82 #include <linux/pid_namespace.h>
  83 #include <linux/ptrace.h>
  84 #include <linux/tracehook.h>
  85 #include <linux/string_helpers.h>
  86 #include <linux/user_namespace.h>
  87 #include <linux/fs_struct.h>
  88
  89 #include <asm/pgtable.h>
  90 #include <asm/processor.h>
  91 #include "internal.h"
  92
  93 static inline void task_name(struct seq_file *m, struct task_struct *p)
  94 {
  95         char *buf;
  96         size_t size;
  97         char tcomm[sizeof(p->comm)];
  98         int ret;
  99
 100         get_task_comm(tcomm, p);
 101
 102         seq_puts(m, "Name:\t");
 103
 104         size = seq_get_buf(m, &buf);
 105         ret = string_escape_str(tcomm, buf, size, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
 106         seq_commit(m, ret < size ? ret : -1);
 107
 108         seq_putc(m, '\n');
 109 }
 110
 111 /*
 112  * The task state array is a strange "bitmap" of
 113  * reasons to sleep. Thus "running" is zero, and
 114  * you can test for combinations of others with
 115  * simple bit tests.
 116  */
 117 static const char * const task_state_array[] = {
 118         "R (running)",          /*   0 */
 119         "S (sleeping)",         /*   1 */
 120         "D (disk sleep)",       /*   2 */
 121         "T (stopped)",          /*   4 */
 122         "t (tracing stop)",     /*   8 */
 123         "X (dead)",             /*  16 */
 124         "Z (zombie)",           /*  32 */
 125 };
 126
 127 static inline const char *get_task_state(struct task_struct *tsk)
 128 {
 129         unsigned int state = (tsk->state | tsk->exit_state) & TASK_REPORT;
 130
 131         /*
 132          * Parked tasks do not run; they sit in __kthread_parkme().
 133          * Without this check, we would report them as running, which is
 134          * clearly wrong, so we report them as sleeping instead.
 135          */
 136         if (tsk->state == TASK_PARKED)
 137                 state = TASK_INTERRUPTIBLE;
 138
 139         BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array)-1);
 140
 141         return task_state_array[fls(state)];
 142 }
 143
 144 static inline int get_task_umask(struct task_struct *tsk)
 145 {
 146         struct fs_struct *fs;
 147         int umask = -ENOENT;
 148
 149         task_lock(tsk);
 150         fs = tsk->fs;
 151         if (fs)
 152                 umask = fs->umask;
 153         task_unlock(tsk);
 154         return umask;
 155 }
 156
 157 static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
 158                                 struct pid *pid, struct task_struct *p)
 159 {
 160         struct user_namespace *user_ns = seq_user_ns(m);
 161         struct group_info *group_info;
 162         int g, umask;
 163         struct task_struct *tracer;
 164         const struct cred *cred;
 165         pid_t ppid, tpid = 0, tgid, ngid;
 166         unsigned int max_fds = 0;
 167
 168         rcu_read_lock();
 169         ppid = pid_alive(p) ?
 170                 task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
 171
 172         tracer = ptrace_parent(p);
 173         if (tracer)
 174                 tpid = task_pid_nr_ns(tracer, ns);
 175
 176         tgid = task_tgid_nr_ns(p, ns);
 177         ngid = task_numa_group_id(p);
 178         cred = get_task_cred(p);
 179
 180         umask = get_task_umask(p);
 181         if (umask >= 0)
 182                 seq_printf(m, "Umask:\t%#04o\n", umask);
 183
 184         task_lock(p);
 185         if (p->files)
 186                 max_fds = files_fdtable(p->files)->max_fds;
 187         task_unlock(p);
 188         rcu_read_unlock();
 189
 190         seq_printf(m, "State:\t%s", get_task_state(p));
 191
 192         seq_put_decimal_ull(m, "\nTgid:\t", tgid);
 193         seq_put_decimal_ull(m, "\nNgid:\t", ngid);
 194         seq_put_decimal_ull(m, "\nPid:\t", pid_nr_ns(pid, ns));
 195         seq_put_decimal_ull(m, "\nPPid:\t", ppid);
 196         seq_put_decimal_ull(m, "\nTracerPid:\t", tpid);
 197         seq_put_decimal_ull(m, "\nUid:\t", from_kuid_munged(user_ns, cred->uid));
 198         seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->euid));
 199         seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->suid));
 200         seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->fsuid));
 201         seq_put_decimal_ull(m, "\nGid:\t", from_kgid_munged(user_ns, cred->gid));
 202         seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->egid));
 203         seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->sgid));
 204         seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->fsgid));
 205         seq_put_decimal_ull(m, "\nFDSize:\t", max_fds);
 206
 207         seq_puts(m, "\nGroups:\t");
 208         group_info = cred->group_info;
 209         for (g = 0; g < group_info->ngroups; g++)
 210                 seq_put_decimal_ull(m, g ? " " : "",
 211                                 from_kgid_munged(user_ns, group_info->gid[g]));
 212         put_cred(cred);
 213         /* Trailing space shouldn't have been added in the first place. */
 214         seq_putc(m, ' ');
 215
 216 #ifdef CONFIG_PID_NS
 217         seq_puts(m, "\nNStgid:");
 218         for (g = ns->level; g <= pid->level; g++)
 219                 seq_put_decimal_ull(m, "\t", task_tgid_nr_ns(p, pid->numbers[g].ns));
 220         seq_puts(m, "\nNSpid:");
 221         for (g = ns->level; g <= pid->level; g++)
 222                 seq_put_decimal_ull(m, "\t", task_pid_nr_ns(p, pid->numbers[g].ns));
 223         seq_puts(m, "\nNSpgid:");
 224         for (g = ns->level; g <= pid->level; g++)
 225                 seq_put_decimal_ull(m, "\t", task_pgrp_nr_ns(p, pid->numbers[g].ns));
 226         seq_puts(m, "\nNSsid:");
 227         for (g = ns->level; g <= pid->level; g++)
 228                 seq_put_decimal_ull(m, "\t", task_session_nr_ns(p, pid->numbers[g].ns));
 229 #endif
 230         seq_putc(m, '\n');
 231 }
 232
 233 void render_sigset_t(struct seq_file *m, const char *header,
 234                                 sigset_t *set)
 235 {
 236         int i;
 237
 238         seq_puts(m, header);
 239
 240         i = _NSIG;
 241         do {
 242                 int x = 0;
 243
 244                 i -= 4;
 245                 if (sigismember(set, i+1)) x |= 1;
 246                 if (sigismember(set, i+2)) x |= 2;
 247                 if (sigismember(set, i+3)) x |= 4;
 248                 if (sigismember(set, i+4)) x |= 8;
 249                 seq_printf(m, "%x", x);
 250         } while (i >= 4);
 251
 252         seq_putc(m, '\n');
 253 }
 254
 255 static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
 256                                     sigset_t *catch)
 257 {
 258         struct k_sigaction *k;
 259         int i;
 260
 261         k = p->sighand->action;
 262         for (i = 1; i <= _NSIG; ++i, ++k) {
 263                 if (k->sa.sa_handler == SIG_IGN)
 264                         sigaddset(ign, i);
 265                 else if (k->sa.sa_handler != SIG_DFL)
 266                         sigaddset(catch, i);
 267         }
 268 }
 269
 270 static inline void task_sig(struct seq_file *m, struct task_struct *p)
 271 {
 272         unsigned long flags;
 273         sigset_t pending, shpending, blocked, ignored, caught;
 274         int num_threads = 0;
 275         unsigned long qsize = 0;
 276         unsigned long qlim = 0;
 277
 278         sigemptyset(&pending);
 279         sigemptyset(&shpending);
 280         sigemptyset(&blocked);
 281         sigemptyset(&ignored);
 282         sigemptyset(&caught);
 283
 284         if (lock_task_sighand(p, &flags)) {
 285                 pending = p->pending.signal;
 286                 shpending = p->signal->shared_pending.signal;
 287                 blocked = p->blocked;
 288                 collect_sigign_sigcatch(p, &ignored, &caught);
 289                 num_threads = get_nr_threads(p);
 290                 rcu_read_lock();  /* FIXME: is this correct? */
 291                 qsize = atomic_read(&__task_cred(p)->user->sigpending);
 292                 rcu_read_unlock();
 293                 qlim = task_rlimit(p, RLIMIT_SIGPENDING);
 294                 unlock_task_sighand(p, &flags);
 295         }
 296
 297         seq_put_decimal_ull(m, "Threads:\t", num_threads);
 298         seq_put_decimal_ull(m, "\nSigQ:\t", qsize);
 299         seq_put_decimal_ull(m, "/", qlim);
 300
 301         /* render them all */
 302         render_sigset_t(m, "\nSigPnd:\t", &pending);
 303         render_sigset_t(m, "ShdPnd:\t", &shpending);
 304         render_sigset_t(m, "SigBlk:\t", &blocked);
 305         render_sigset_t(m, "SigIgn:\t", &ignored);
 306         render_sigset_t(m, "SigCgt:\t", &caught);
 307 }
 308
 309 static void render_cap_t(struct seq_file *m, const char *header,
 310                         kernel_cap_t *a)
 311 {
 312         unsigned __capi;
 313
 314         seq_puts(m, header);
 315         CAP_FOR_EACH_U32(__capi) {
 316                 seq_printf(m, "%08x",
 317                            a->cap[CAP_LAST_U32 - __capi]);
 318         }
 319         seq_putc(m, '\n');
 320 }
 321
 322 static inline void task_cap(struct seq_file *m, struct task_struct *p)
 323 {
 324         const struct cred *cred;
 325         kernel_cap_t cap_inheritable, cap_permitted, cap_effective,
 326                         cap_bset, cap_ambient;
 327
 328         rcu_read_lock();
 329         cred = __task_cred(p);
 330         cap_inheritable = cred->cap_inheritable;
 331         cap_permitted   = cred->cap_permitted;
 332         cap_effective   = cred->cap_effective;
 333         cap_bset        = cred->cap_bset;
 334         cap_ambient     = cred->cap_ambient;
 335         rcu_read_unlock();
 336
 337         render_cap_t(m, "CapInh:\t", &cap_inheritable);
 338         render_cap_t(m, "CapPrm:\t", &cap_permitted);
 339         render_cap_t(m, "CapEff:\t", &cap_effective);
 340         render_cap_t(m, "CapBnd:\t", &cap_bset);
 341         render_cap_t(m, "CapAmb:\t", &cap_ambient);
 342 }
 343
 344 static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
 345 {
 346 #ifdef CONFIG_SECCOMP
 347         seq_put_decimal_ull(m, "Seccomp:\t", p->seccomp.mode);
 348         seq_putc(m, '\n');
 349 #endif
 350 }
 351
 352 static inline void task_context_switch_counts(struct seq_file *m,
 353                                                 struct task_struct *p)
 354 {
 355         seq_put_decimal_ull(m, "voluntary_ctxt_switches:\t", p->nvcsw);
 356         seq_put_decimal_ull(m, "\nnonvoluntary_ctxt_switches:\t", p->nivcsw);
 357         seq_putc(m, '\n');
 358 }
 359
 360 static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
 361 {
 362         seq_printf(m, "Cpus_allowed:\t%*pb\n",
 363                    cpumask_pr_args(&task->cpus_allowed));
 364         seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
 365                    cpumask_pr_args(&task->cpus_allowed));
 366 }
 367
 368 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 369                         struct pid *pid, struct task_struct *task)
 370 {
 371         struct mm_struct *mm = get_task_mm(task);
 372
 373         task_name(m, task);
 374         task_state(m, ns, pid, task);
 375
 376         if (mm) {
 377                 task_mem(m, mm);
 378                 mmput(mm);
 379         }
 380         task_sig(m, task);
 381         task_cap(m, task);
 382         task_seccomp(m, task);
 383         task_cpus_allowed(m, task);
 384         cpuset_task_status_allowed(m, task);
 385         task_context_switch_counts(m, task);
 386         return 0;
 387 }
 388
 389 static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 390                         struct pid *pid, struct task_struct *task, int whole)
 391 {
 392         unsigned long vsize, eip, esp, wchan = 0;
 393         int priority, nice;
 394         int tty_pgrp = -1, tty_nr = 0;
 395         sigset_t sigign, sigcatch;
 396         char state;
 397         pid_t ppid = 0, pgid = -1, sid = -1;
 398         int num_threads = 0;
 399         int permitted;
 400         struct mm_struct *mm;
 401         unsigned long long start_time;
 402         unsigned long cmin_flt = 0, cmaj_flt = 0;
 403         unsigned long  min_flt = 0,  maj_flt = 0;
 404         cputime_t cutime, cstime, utime, stime;
 405         cputime_t cgtime, gtime;
 406         unsigned long rsslim = 0;
 407         char tcomm[sizeof(task->comm)];
 408         unsigned long flags;
 409
 410         state = *get_task_state(task);
 411         vsize = eip = esp = 0;
 412         permitted = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS | PTRACE_MODE_NOAUDIT);
 413         mm = get_task_mm(task);
 414         if (mm) {
 415                 vsize = task_vsize(mm);
 416                 /*
 417                  * esp and eip are intentionally zeroed out.  There is no
 418                  * non-racy way to read them without freezing the task.
 419                  * Programs that need reliable values can use ptrace(2).
 420                  *
 421                  * The only exception is if the task is core dumping because
 422                  * a program is not able to use ptrace(2) in that case. It is
 423                  * safe because the task has stopped executing permanently.
 424                  */
 425                 if (permitted && (task->flags & PF_DUMPCORE)) {
 426                         eip = KSTK_EIP(task);
 427                         esp = KSTK_ESP(task);
 428                 }
 429         }
 430
 431         get_task_comm(tcomm, task);
 432
 433         sigemptyset(&sigign);
 434         sigemptyset(&sigcatch);
 435         cutime = cstime = utime = stime = 0;
 436         cgtime = gtime = 0;
 437
 438         if (lock_task_sighand(task, &flags)) {
 439                 struct signal_struct *sig = task->signal;
 440
 441                 if (sig->tty) {
 442                         struct pid *pgrp = tty_get_pgrp(sig->tty);
 443                         tty_pgrp = pid_nr_ns(pgrp, ns);
 444                         put_pid(pgrp);
 445                         tty_nr = new_encode_dev(tty_devnum(sig->tty));
 446                 }
 447
 448                 num_threads = get_nr_threads(task);
 449                 collect_sigign_sigcatch(task, &sigign, &sigcatch);
 450
 451                 cmin_flt = sig->cmin_flt;
 452                 cmaj_flt = sig->cmaj_flt;
 453                 cutime = sig->cutime;
 454                 cstime = sig->cstime;
 455                 cgtime = sig->cgtime;
 456                 rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
 457
 458                 /* add up live thread stats at the group level */
 459                 if (whole) {
 460                         struct task_struct *t = task;
 461                         do {
 462                                 min_flt += t->min_flt;
 463                                 maj_flt += t->maj_flt;
 464                                 gtime += task_gtime(t);
 465                         } while_each_thread(task, t);
 466
 467                         min_flt += sig->min_flt;
 468                         maj_flt += sig->maj_flt;
 469                         thread_group_cputime_adjusted(task, &utime, &stime);
 470                         gtime += sig->gtime;
 471                 }
 472
 473                 sid = task_session_nr_ns(task, ns);
 474                 ppid = task_tgid_nr_ns(task->real_parent, ns);
 475                 pgid = task_pgrp_nr_ns(task, ns);
 476
 477                 unlock_task_sighand(task, &flags);
 478         }
 479
 480         if (permitted && (!whole || num_threads < 2))
 481                 wchan = get_wchan(task);
 482         if (!whole) {
 483                 min_flt = task->min_flt;
 484                 maj_flt = task->maj_flt;
 485                 task_cputime_adjusted(task, &utime, &stime);
 486                 gtime = task_gtime(task);
 487         }
 488
 489         /* scale priority and nice values from timeslices to -20..20 */
 490         /* to make it look like a "normal" Unix priority/nice value  */
 491         priority = task_prio(task);
 492         nice = task_nice(task);
 493
 494         /* convert nsec -> ticks */
 495         start_time = nsec_to_clock_t(task->real_start_time);
 496
 497         seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
 498         seq_put_decimal_ll(m, " ", ppid);
 499         seq_put_decimal_ll(m, " ", pgid);
 500         seq_put_decimal_ll(m, " ", sid);
 501         seq_put_decimal_ll(m, " ", tty_nr);
 502         seq_put_decimal_ll(m, " ", tty_pgrp);
 503         seq_put_decimal_ull(m, " ", task->flags);
 504         seq_put_decimal_ull(m, " ", min_flt);
 505         seq_put_decimal_ull(m, " ", cmin_flt);
 506         seq_put_decimal_ull(m, " ", maj_flt);
 507         seq_put_decimal_ull(m, " ", cmaj_flt);
 508         seq_put_decimal_ull(m, " ", cputime_to_clock_t(utime));
 509         seq_put_decimal_ull(m, " ", cputime_to_clock_t(stime));
 510         seq_put_decimal_ll(m, " ", cputime_to_clock_t(cutime));
 511         seq_put_decimal_ll(m, " ", cputime_to_clock_t(cstime));
 512         seq_put_decimal_ll(m, " ", priority);
 513         seq_put_decimal_ll(m, " ", nice);
 514         seq_put_decimal_ll(m, " ", num_threads);
 515         seq_put_decimal_ull(m, " ", 0);
 516         seq_put_decimal_ull(m, " ", start_time);
 517         seq_put_decimal_ull(m, " ", vsize);
 518         seq_put_decimal_ull(m, " ", mm ? get_mm_rss(mm) : 0);
 519         seq_put_decimal_ull(m, " ", rsslim);
 520         seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->start_code : 1) : 0);
 521         seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->end_code : 1) : 0);
 522         seq_put_decimal_ull(m, " ", (permitted && mm) ? mm->start_stack : 0);
 523         seq_put_decimal_ull(m, " ", esp);
 524         seq_put_decimal_ull(m, " ", eip);
 525         /* The signal information here is obsolete.
 526          * It must be decimal for Linux 2.0 compatibility.
 527          * Use /proc/#/status for real-time signals.
 528          */
 529         seq_put_decimal_ull(m, " ", task->pending.signal.sig[0] & 0x7fffffffUL);
 530         seq_put_decimal_ull(m, " ", task->blocked.sig[0] & 0x7fffffffUL);
 531         seq_put_decimal_ull(m, " ", sigign.sig[0] & 0x7fffffffUL);
 532         seq_put_decimal_ull(m, " ", sigcatch.sig[0] & 0x7fffffffUL);
 533
 534         /*
 535          * We used to output the absolute kernel address, but that's an
 536          * information leak - so instead we show a 0/1 flag here, to signal
 537          * to user-space whether there's a wchan field in /proc/PID/wchan.
 538          *
 539          * This works with older implementations of procps as well.
 540          */
 541         if (wchan)
 542                 seq_puts(m, " 1");
 543         else
 544                 seq_puts(m, " 0");
 545
 546         seq_put_decimal_ull(m, " ", 0);
 547         seq_put_decimal_ull(m, " ", 0);
 548         seq_put_decimal_ll(m, " ", task->exit_signal);
 549         seq_put_decimal_ll(m, " ", task_cpu(task));
 550         seq_put_decimal_ull(m, " ", task->rt_priority);
 551         seq_put_decimal_ull(m, " ", task->policy);
 552         seq_put_decimal_ull(m, " ", delayacct_blkio_ticks(task));
 553         seq_put_decimal_ull(m, " ", cputime_to_clock_t(gtime));
 554         seq_put_decimal_ll(m, " ", cputime_to_clock_t(cgtime));
 555
 556         if (mm && permitted) {
 557                 seq_put_decimal_ull(m, " ", mm->start_data);
 558                 seq_put_decimal_ull(m, " ", mm->end_data);
 559                 seq_put_decimal_ull(m, " ", mm->start_brk);
 560                 seq_put_decimal_ull(m, " ", mm->arg_start);
 561                 seq_put_decimal_ull(m, " ", mm->arg_end);
 562                 seq_put_decimal_ull(m, " ", mm->env_start);
 563                 seq_put_decimal_ull(m, " ", mm->env_end);
 564         } else
 565                 seq_puts(m, " 0 0 0 0 0 0 0");
 566
 567         if (permitted)
 568                 seq_put_decimal_ll(m, " ", task->exit_code);
 569         else
 570                 seq_puts(m, " 0");
 571
 572         seq_putc(m, '\n');
 573         if (mm)
 574                 mmput(mm);
 575         return 0;
 576 }
 577
 578 int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
 579                         struct pid *pid, struct task_struct *task)
 580 {
 581         return do_task_stat(m, ns, pid, task, 0);
 582 }
 583
 584 int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
 585                         struct pid *pid, struct task_struct *task)
 586 {
 587         return do_task_stat(m, ns, pid, task, 1);
 588 }
 589
 590 int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
 591                         struct pid *pid, struct task_struct *task)
 592 {
 593         unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0;
 594         struct mm_struct *mm = get_task_mm(task);
 595
 596         if (mm) {
 597                 size = task_statm(mm, &shared, &text, &data, &resident);
 598                 mmput(mm);
 599         }
 600         /*
 601          * For quick read, open code by putting numbers directly
 602          * expected format is
 603          * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
 604          *               size, resident, shared, text, data);
 605          */
 606         seq_put_decimal_ull(m, "", size);
 607         seq_put_decimal_ull(m, " ", resident);
 608         seq_put_decimal_ull(m, " ", shared);
 609         seq_put_decimal_ull(m, " ", text);
 610         seq_put_decimal_ull(m, " ", 0);
 611         seq_put_decimal_ull(m, " ", data);
 612         seq_put_decimal_ull(m, " ", 0);
 613         seq_putc(m, '\n');
 614
 615         return 0;
 616 }
 617
 618 #ifdef CONFIG_PROC_CHILDREN
 619 static struct pid *
 620 get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
 621 {
 622         struct task_struct *start, *task;
 623         struct pid *pid = NULL;
 624
 625         read_lock(&tasklist_lock);
 626
 627         start = pid_task(proc_pid(inode), PIDTYPE_PID);
 628         if (!start)
 629                 goto out;
 630
 631         /*
 632          * Lets try to continue searching first, this gives
 633          * us significant speedup on children-rich processes.
 634          */
 635         if (pid_prev) {
 636                 task = pid_task(pid_prev, PIDTYPE_PID);
 637                 if (task && task->real_parent == start &&
 638                     !(list_empty(&task->sibling))) {
 639                         if (list_is_last(&task->sibling, &start->children))
 640                                 goto out;
 641                         task = list_first_entry(&task->sibling,
 642                                                 struct task_struct, sibling);
 643                         pid = get_pid(task_pid(task));
 644                         goto out;
 645                 }
 646         }
 647
 648         /*
 649          * Slow search case.
 650          *
 651          * We might miss some children here if children
 652          * are exited while we were not holding the lock,
 653          * but it was never promised to be accurate that
 654          * much.
 655          *
 656          * "Just suppose that the parent sleeps, but N children
 657          *  exit after we printed their tids. Now the slow paths
 658          *  skips N extra children, we miss N tasks." (c)
 659          *
 660          * So one need to stop or freeze the leader and all
 661          * its children to get a precise result.
 662          */
 663         list_for_each_entry(task, &start->children, sibling) {
 664                 if (pos-- == 0) {
 665                         pid = get_pid(task_pid(task));
 666                         break;
 667                 }
 668         }
 669
 670 out:
 671         read_unlock(&tasklist_lock);
 672         return pid;
 673 }
 674
 675 static int children_seq_show(struct seq_file *seq, void *v)
 676 {
 677         struct inode *inode = seq->private;
 678         pid_t pid;
 679
 680         pid = pid_nr_ns(v, inode->i_sb->s_fs_info);
 681         seq_printf(seq, "%d ", pid);
 682
 683         return 0;
 684 }
 685
 686 static void *children_seq_start(struct seq_file *seq, loff_t *pos)
 687 {
 688         return get_children_pid(seq->private, NULL, *pos);
 689 }
 690
 691 static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 692 {
 693         struct pid *pid;
 694
 695         pid = get_children_pid(seq->private, v, *pos + 1);
 696         put_pid(v);
 697
 698         ++*pos;
 699         return pid;
 700 }
 701
 702 static void children_seq_stop(struct seq_file *seq, void *v)
 703 {
 704         put_pid(v);
 705 }
 706
 707 static const struct seq_operations children_seq_ops = {
 708         .start  = children_seq_start,
 709         .next   = children_seq_next,
 710         .stop   = children_seq_stop,
 711         .show   = children_seq_show,
 712 };
 713
 714 static int children_seq_open(struct inode *inode, struct file *file)
 715 {
 716         struct seq_file *m;
 717         int ret;
 718
 719         ret = seq_open(file, &children_seq_ops);
 720         if (ret)
 721                 return ret;
 722
 723         m = file->private_data;
 724         m->private = inode;
 725
 726         return ret;
 727 }
 728
 729 int children_seq_release(struct inode *inode, struct file *file)
 730 {
 731         seq_release(inode, file);
 732         return 0;
 733 }
 734
 735 const struct file_operations proc_tid_children_operations = {
 736         .open    = children_seq_open,
 737         .read    = seq_read,
 738         .llseek  = seq_lseek,
 739         .release = children_seq_release,
 740 };
 741 #endif /* CONFIG_PROC_CHILDREN */