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/mm.h>
  64 #include <linux/sched/numa_balancing.h>
  65 #include <linux/sched/task_stack.h>
  66 #include <linux/sched/task.h>
  67 #include <linux/sched/cputime.h>
  68 #include <linux/proc_fs.h>
  69 #include <linux/ioport.h>
  70 #include <linux/uaccess.h>
  71 #include <linux/io.h>
  72 #include <linux/mm.h>
  73 #include <linux/hugetlb.h>
  74 #include <linux/pagemap.h>
  75 #include <linux/swap.h>
  76 #include <linux/smp.h>
  77 #include <linux/signal.h>
  78 #include <linux/highmem.h>
  79 #include <linux/file.h>
  80 #include <linux/fdtable.h>
  81 #include <linux/times.h>
  82 #include <linux/cpuset.h>
  83 #include <linux/rcupdate.h>
  84 #include <linux/delayacct.h>
  85 #include <linux/seq_file.h>
  86 #include <linux/pid_namespace.h>
  87 #include <linux/nospec.h>
  88 #include <linux/prctl.h>
  89 #include <linux/ptrace.h>
  90 #include <linux/tracehook.h>
  91 #include <linux/string_helpers.h>
  92 #include <linux/user_namespace.h>
  93 #include <linux/fs_struct.h>
  94
  95 #include <asm/pgtable.h>
  96 #include <asm/processor.h>
  97 #include "internal.h"
  98
  99 static inline void task_name(struct seq_file *m, struct task_struct *p)
 100 {
 101         char *buf;
 102         size_t size;
 103         char tcomm[sizeof(p->comm)];
 104         int ret;
 105
 106         get_task_comm(tcomm, p);
 107
 108         seq_puts(m, "Name:\t");
 109
 110         size = seq_get_buf(m, &buf);
 111         ret = string_escape_str(tcomm, buf, size, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
 112         seq_commit(m, ret < size ? ret : -1);
 113
 114         seq_putc(m, '\n');
 115 }
 116
 117 /*
 118  * The task state array is a strange "bitmap" of
 119  * reasons to sleep. Thus "running" is zero, and
 120  * you can test for combinations of others with
 121  * simple bit tests.
 122  */
 123 static const char * const task_state_array[] = {
 124         "R (running)",          /*   0 */
 125         "S (sleeping)",         /*   1 */
 126         "D (disk sleep)",       /*   2 */
 127         "T (stopped)",          /*   4 */
 128         "t (tracing stop)",     /*   8 */
 129         "X (dead)",             /*  16 */
 130         "Z (zombie)",           /*  32 */
 131 };
 132
 133 static inline const char *get_task_state(struct task_struct *tsk)
 134 {
 135         unsigned int state = (tsk->state | tsk->exit_state) & TASK_REPORT;
 136
 137         /*
 138          * Parked tasks do not run; they sit in __kthread_parkme().
 139          * Without this check, we would report them as running, which is
 140          * clearly wrong, so we report them as sleeping instead.
 141          */
 142         if (tsk->state == TASK_PARKED)
 143                 state = TASK_INTERRUPTIBLE;
 144
 145         BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array)-1);
 146
 147         return task_state_array[fls(state)];
 148 }
 149
 150 static inline int get_task_umask(struct task_struct *tsk)
 151 {
 152         struct fs_struct *fs;
 153         int umask = -ENOENT;
 154
 155         task_lock(tsk);
 156         fs = tsk->fs;
 157         if (fs)
 158                 umask = fs->umask;
 159         task_unlock(tsk);
 160         return umask;
 161 }
 162
 163 static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
 164                                 struct pid *pid, struct task_struct *p)
 165 {
 166         struct user_namespace *user_ns = seq_user_ns(m);
 167         struct group_info *group_info;
 168         int g, umask;
 169         struct task_struct *tracer;
 170         const struct cred *cred;
 171         pid_t ppid, tpid = 0, tgid, ngid;
 172         unsigned int max_fds = 0;
 173
 174         rcu_read_lock();
 175         ppid = pid_alive(p) ?
 176                 task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
 177
 178         tracer = ptrace_parent(p);
 179         if (tracer)
 180                 tpid = task_pid_nr_ns(tracer, ns);
 181
 182         tgid = task_tgid_nr_ns(p, ns);
 183         ngid = task_numa_group_id(p);
 184         cred = get_task_cred(p);
 185
 186         umask = get_task_umask(p);
 187         if (umask >= 0)
 188                 seq_printf(m, "Umask:\t%#04o\n", umask);
 189
 190         task_lock(p);
 191         if (p->files)
 192                 max_fds = files_fdtable(p->files)->max_fds;
 193         task_unlock(p);
 194         rcu_read_unlock();
 195
 196         seq_printf(m, "State:\t%s", get_task_state(p));
 197
 198         seq_put_decimal_ull(m, "\nTgid:\t", tgid);
 199         seq_put_decimal_ull(m, "\nNgid:\t", ngid);
 200         seq_put_decimal_ull(m, "\nPid:\t", pid_nr_ns(pid, ns));
 201         seq_put_decimal_ull(m, "\nPPid:\t", ppid);
 202         seq_put_decimal_ull(m, "\nTracerPid:\t", tpid);
 203         seq_put_decimal_ull(m, "\nUid:\t", from_kuid_munged(user_ns, cred->uid));
 204         seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->euid));
 205         seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->suid));
 206         seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->fsuid));
 207         seq_put_decimal_ull(m, "\nGid:\t", from_kgid_munged(user_ns, cred->gid));
 208         seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->egid));
 209         seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->sgid));
 210         seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->fsgid));
 211         seq_put_decimal_ull(m, "\nFDSize:\t", max_fds);
 212
 213         seq_puts(m, "\nGroups:\t");
 214         group_info = cred->group_info;
 215         for (g = 0; g < group_info->ngroups; g++)
 216                 seq_put_decimal_ull(m, g ? " " : "",
 217                                 from_kgid_munged(user_ns, group_info->gid[g]));
 218         put_cred(cred);
 219         /* Trailing space shouldn't have been added in the first place. */
 220         seq_putc(m, ' ');
 221
 222 #ifdef CONFIG_PID_NS
 223         seq_puts(m, "\nNStgid:");
 224         for (g = ns->level; g <= pid->level; g++)
 225                 seq_put_decimal_ull(m, "\t", task_tgid_nr_ns(p, pid->numbers[g].ns));
 226         seq_puts(m, "\nNSpid:");
 227         for (g = ns->level; g <= pid->level; g++)
 228                 seq_put_decimal_ull(m, "\t", task_pid_nr_ns(p, pid->numbers[g].ns));
 229         seq_puts(m, "\nNSpgid:");
 230         for (g = ns->level; g <= pid->level; g++)
 231                 seq_put_decimal_ull(m, "\t", task_pgrp_nr_ns(p, pid->numbers[g].ns));
 232         seq_puts(m, "\nNSsid:");
 233         for (g = ns->level; g <= pid->level; g++)
 234                 seq_put_decimal_ull(m, "\t", task_session_nr_ns(p, pid->numbers[g].ns));
 235 #endif
 236         seq_putc(m, '\n');
 237 }
 238
 239 void render_sigset_t(struct seq_file *m, const char *header,
 240                                 sigset_t *set)
 241 {
 242         int i;
 243
 244         seq_puts(m, header);
 245
 246         i = _NSIG;
 247         do {
 248                 int x = 0;
 249
 250                 i -= 4;
 251                 if (sigismember(set, i+1)) x |= 1;
 252                 if (sigismember(set, i+2)) x |= 2;
 253                 if (sigismember(set, i+3)) x |= 4;
 254                 if (sigismember(set, i+4)) x |= 8;
 255                 seq_putc(m, hex_asc[x]);
 256         } while (i >= 4);
 257
 258         seq_putc(m, '\n');
 259 }
 260
 261 static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
 262                                     sigset_t *catch)
 263 {
 264         struct k_sigaction *k;
 265         int i;
 266
 267         k = p->sighand->action;
 268         for (i = 1; i <= _NSIG; ++i, ++k) {
 269                 if (k->sa.sa_handler == SIG_IGN)
 270                         sigaddset(ign, i);
 271                 else if (k->sa.sa_handler != SIG_DFL)
 272                         sigaddset(catch, i);
 273         }
 274 }
 275
 276 static inline void task_sig(struct seq_file *m, struct task_struct *p)
 277 {
 278         unsigned long flags;
 279         sigset_t pending, shpending, blocked, ignored, caught;
 280         int num_threads = 0;
 281         unsigned long qsize = 0;
 282         unsigned long qlim = 0;
 283
 284         sigemptyset(&pending);
 285         sigemptyset(&shpending);
 286         sigemptyset(&blocked);
 287         sigemptyset(&ignored);
 288         sigemptyset(&caught);
 289
 290         if (lock_task_sighand(p, &flags)) {
 291                 pending = p->pending.signal;
 292                 shpending = p->signal->shared_pending.signal;
 293                 blocked = p->blocked;
 294                 collect_sigign_sigcatch(p, &ignored, &caught);
 295                 num_threads = get_nr_threads(p);
 296                 rcu_read_lock();  /* FIXME: is this correct? */
 297                 qsize = atomic_read(&__task_cred(p)->user->sigpending);
 298                 rcu_read_unlock();
 299                 qlim = task_rlimit(p, RLIMIT_SIGPENDING);
 300                 unlock_task_sighand(p, &flags);
 301         }
 302
 303         seq_put_decimal_ull(m, "Threads:\t", num_threads);
 304         seq_put_decimal_ull(m, "\nSigQ:\t", qsize);
 305         seq_put_decimal_ull(m, "/", qlim);
 306
 307         /* render them all */
 308         render_sigset_t(m, "\nSigPnd:\t", &pending);
 309         render_sigset_t(m, "ShdPnd:\t", &shpending);
 310         render_sigset_t(m, "SigBlk:\t", &blocked);
 311         render_sigset_t(m, "SigIgn:\t", &ignored);
 312         render_sigset_t(m, "SigCgt:\t", &caught);
 313 }
 314
 315 static void render_cap_t(struct seq_file *m, const char *header,
 316                         kernel_cap_t *a)
 317 {
 318         unsigned __capi;
 319
 320         seq_puts(m, header);
 321         CAP_FOR_EACH_U32(__capi) {
 322                 seq_printf(m, "%08x",
 323                            a->cap[CAP_LAST_U32 - __capi]);
 324         }
 325         seq_putc(m, '\n');
 326 }
 327
 328 static inline void task_cap(struct seq_file *m, struct task_struct *p)
 329 {
 330         const struct cred *cred;
 331         kernel_cap_t cap_inheritable, cap_permitted, cap_effective,
 332                         cap_bset, cap_ambient;
 333
 334         rcu_read_lock();
 335         cred = __task_cred(p);
 336         cap_inheritable = cred->cap_inheritable;
 337         cap_permitted   = cred->cap_permitted;
 338         cap_effective   = cred->cap_effective;
 339         cap_bset        = cred->cap_bset;
 340         cap_ambient     = cred->cap_ambient;
 341         rcu_read_unlock();
 342
 343         render_cap_t(m, "CapInh:\t", &cap_inheritable);
 344         render_cap_t(m, "CapPrm:\t", &cap_permitted);
 345         render_cap_t(m, "CapEff:\t", &cap_effective);
 346         render_cap_t(m, "CapBnd:\t", &cap_bset);
 347         render_cap_t(m, "CapAmb:\t", &cap_ambient);
 348 }
 349
 350 static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
 351 {
 352         seq_put_decimal_ull(m, "NoNewPrivs:\t", task_no_new_privs(p));
 353 #ifdef CONFIG_SECCOMP
 354         seq_put_decimal_ull(m, "\nSeccomp:\t", p->seccomp.mode);
 355 #endif
 356         seq_printf(m, "\nSpeculation Store Bypass:\t");
 357         switch (arch_prctl_spec_ctrl_get(p, PR_SPEC_STORE_BYPASS)) {
 358         case -EINVAL:
 359                 seq_printf(m, "unknown");
 360                 break;
 361         case PR_SPEC_NOT_AFFECTED:
 362                 seq_printf(m, "not vulnerable");
 363                 break;
 364         case PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE:
 365                 seq_printf(m, "thread force mitigated");
 366                 break;
 367         case PR_SPEC_PRCTL | PR_SPEC_DISABLE:
 368                 seq_printf(m, "thread mitigated");
 369                 break;
 370         case PR_SPEC_PRCTL | PR_SPEC_ENABLE:
 371                 seq_printf(m, "thread vulnerable");
 372                 break;
 373         case PR_SPEC_DISABLE:
 374                 seq_printf(m, "globally mitigated");
 375                 break;
 376         default:
 377                 seq_printf(m, "vulnerable");
 378                 break;
 379         }
 380         seq_putc(m, '\n');
 381 }
 382
 383 static inline void task_context_switch_counts(struct seq_file *m,
 384                                                 struct task_struct *p)
 385 {
 386         seq_put_decimal_ull(m, "voluntary_ctxt_switches:\t", p->nvcsw);
 387         seq_put_decimal_ull(m, "\nnonvoluntary_ctxt_switches:\t", p->nivcsw);
 388         seq_putc(m, '\n');
 389 }
 390
 391 static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
 392 {
 393         seq_printf(m, "Cpus_allowed:\t%*pb\n",
 394                    cpumask_pr_args(&task->cpus_allowed));
 395         seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
 396                    cpumask_pr_args(&task->cpus_allowed));
 397 }
 398
 399 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 400                         struct pid *pid, struct task_struct *task)
 401 {
 402         struct mm_struct *mm = get_task_mm(task);
 403
 404         task_name(m, task);
 405         task_state(m, ns, pid, task);
 406
 407         if (mm) {
 408                 task_mem(m, mm);
 409                 mmput(mm);
 410         }
 411         task_sig(m, task);
 412         task_cap(m, task);
 413         task_seccomp(m, task);
 414         task_cpus_allowed(m, task);
 415         cpuset_task_status_allowed(m, task);
 416         task_context_switch_counts(m, task);
 417         return 0;
 418 }
 419
 420 static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 421                         struct pid *pid, struct task_struct *task, int whole)
 422 {
 423         unsigned long vsize, eip, esp, wchan = 0;
 424         int priority, nice;
 425         int tty_pgrp = -1, tty_nr = 0;
 426         sigset_t sigign, sigcatch;
 427         char state;
 428         pid_t ppid = 0, pgid = -1, sid = -1;
 429         int num_threads = 0;
 430         int permitted;
 431         struct mm_struct *mm;
 432         unsigned long long start_time;
 433         unsigned long cmin_flt = 0, cmaj_flt = 0;
 434         unsigned long  min_flt = 0,  maj_flt = 0;
 435         u64 cutime, cstime, utime, stime;
 436         u64 cgtime, gtime;
 437         unsigned long rsslim = 0;
 438         char tcomm[sizeof(task->comm)];
 439         unsigned long flags;
 440
 441         state = *get_task_state(task);
 442         vsize = eip = esp = 0;
 443         permitted = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS | PTRACE_MODE_NOAUDIT);
 444         mm = get_task_mm(task);
 445         if (mm) {
 446                 vsize = task_vsize(mm);
 447                 /*
 448                  * esp and eip are intentionally zeroed out.  There is no
 449                  * non-racy way to read them without freezing the task.
 450                  * Programs that need reliable values can use ptrace(2).
 451                  *
 452                  * The only exception is if the task is core dumping because
 453                  * a program is not able to use ptrace(2) in that case. It is
 454                  * safe because the task has stopped executing permanently.
 455                  */
 456                 if (permitted && (task->flags & PF_DUMPCORE)) {
 457                         eip = KSTK_EIP(task);
 458                         esp = KSTK_ESP(task);
 459                 }
 460         }
 461
 462         get_task_comm(tcomm, task);
 463
 464         sigemptyset(&sigign);
 465         sigemptyset(&sigcatch);
 466         cutime = cstime = utime = stime = 0;
 467         cgtime = gtime = 0;
 468
 469         if (lock_task_sighand(task, &flags)) {
 470                 struct signal_struct *sig = task->signal;
 471
 472                 if (sig->tty) {
 473                         struct pid *pgrp = tty_get_pgrp(sig->tty);
 474                         tty_pgrp = pid_nr_ns(pgrp, ns);
 475                         put_pid(pgrp);
 476                         tty_nr = new_encode_dev(tty_devnum(sig->tty));
 477                 }
 478
 479                 num_threads = get_nr_threads(task);
 480                 collect_sigign_sigcatch(task, &sigign, &sigcatch);
 481
 482                 cmin_flt = sig->cmin_flt;
 483                 cmaj_flt = sig->cmaj_flt;
 484                 cutime = sig->cutime;
 485                 cstime = sig->cstime;
 486                 cgtime = sig->cgtime;
 487                 rsslim = ACCESS_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
 488
 489                 /* add up live thread stats at the group level */
 490                 if (whole) {
 491                         struct task_struct *t = task;
 492                         do {
 493                                 min_flt += t->min_flt;
 494                                 maj_flt += t->maj_flt;
 495                                 gtime += task_gtime(t);
 496                         } while_each_thread(task, t);
 497
 498                         min_flt += sig->min_flt;
 499                         maj_flt += sig->maj_flt;
 500                         thread_group_cputime_adjusted(task, &utime, &stime);
 501                         gtime += sig->gtime;
 502                 }
 503
 504                 sid = task_session_nr_ns(task, ns);
 505                 ppid = task_tgid_nr_ns(task->real_parent, ns);
 506                 pgid = task_pgrp_nr_ns(task, ns);
 507
 508                 unlock_task_sighand(task, &flags);
 509         }
 510
 511         if (permitted && (!whole || num_threads < 2))
 512                 wchan = get_wchan(task);
 513         if (!whole) {
 514                 min_flt = task->min_flt;
 515                 maj_flt = task->maj_flt;
 516                 task_cputime_adjusted(task, &utime, &stime);
 517                 gtime = task_gtime(task);
 518         }
 519
 520         /* scale priority and nice values from timeslices to -20..20 */
 521         /* to make it look like a "normal" Unix priority/nice value  */
 522         priority = task_prio(task);
 523         nice = task_nice(task);
 524
 525         /* convert nsec -> ticks */
 526         start_time = nsec_to_clock_t(task->real_start_time);
 527
 528         seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
 529         seq_put_decimal_ll(m, " ", ppid);
 530         seq_put_decimal_ll(m, " ", pgid);
 531         seq_put_decimal_ll(m, " ", sid);
 532         seq_put_decimal_ll(m, " ", tty_nr);
 533         seq_put_decimal_ll(m, " ", tty_pgrp);
 534         seq_put_decimal_ull(m, " ", task->flags);
 535         seq_put_decimal_ull(m, " ", min_flt);
 536         seq_put_decimal_ull(m, " ", cmin_flt);
 537         seq_put_decimal_ull(m, " ", maj_flt);
 538         seq_put_decimal_ull(m, " ", cmaj_flt);
 539         seq_put_decimal_ull(m, " ", nsec_to_clock_t(utime));
 540         seq_put_decimal_ull(m, " ", nsec_to_clock_t(stime));
 541         seq_put_decimal_ll(m, " ", nsec_to_clock_t(cutime));
 542         seq_put_decimal_ll(m, " ", nsec_to_clock_t(cstime));
 543         seq_put_decimal_ll(m, " ", priority);
 544         seq_put_decimal_ll(m, " ", nice);
 545         seq_put_decimal_ll(m, " ", num_threads);
 546         seq_put_decimal_ull(m, " ", 0);
 547         seq_put_decimal_ull(m, " ", start_time);
 548         seq_put_decimal_ull(m, " ", vsize);
 549         seq_put_decimal_ull(m, " ", mm ? get_mm_rss(mm) : 0);
 550         seq_put_decimal_ull(m, " ", rsslim);
 551         seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->start_code : 1) : 0);
 552         seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->end_code : 1) : 0);
 553         seq_put_decimal_ull(m, " ", (permitted && mm) ? mm->start_stack : 0);
 554         seq_put_decimal_ull(m, " ", esp);
 555         seq_put_decimal_ull(m, " ", eip);
 556         /* The signal information here is obsolete.
 557          * It must be decimal for Linux 2.0 compatibility.
 558          * Use /proc/#/status for real-time signals.
 559          */
 560         seq_put_decimal_ull(m, " ", task->pending.signal.sig[0] & 0x7fffffffUL);
 561         seq_put_decimal_ull(m, " ", task->blocked.sig[0] & 0x7fffffffUL);
 562         seq_put_decimal_ull(m, " ", sigign.sig[0] & 0x7fffffffUL);
 563         seq_put_decimal_ull(m, " ", sigcatch.sig[0] & 0x7fffffffUL);
 564
 565         /*
 566          * We used to output the absolute kernel address, but that's an
 567          * information leak - so instead we show a 0/1 flag here, to signal
 568          * to user-space whether there's a wchan field in /proc/PID/wchan.
 569          *
 570          * This works with older implementations of procps as well.
 571          */
 572         if (wchan)
 573                 seq_puts(m, " 1");
 574         else
 575                 seq_puts(m, " 0");
 576
 577         seq_put_decimal_ull(m, " ", 0);
 578         seq_put_decimal_ull(m, " ", 0);
 579         seq_put_decimal_ll(m, " ", task->exit_signal);
 580         seq_put_decimal_ll(m, " ", task_cpu(task));
 581         seq_put_decimal_ull(m, " ", task->rt_priority);
 582         seq_put_decimal_ull(m, " ", task->policy);
 583         seq_put_decimal_ull(m, " ", delayacct_blkio_ticks(task));
 584         seq_put_decimal_ull(m, " ", nsec_to_clock_t(gtime));
 585         seq_put_decimal_ll(m, " ", nsec_to_clock_t(cgtime));
 586
 587         if (mm && permitted) {
 588                 seq_put_decimal_ull(m, " ", mm->start_data);
 589                 seq_put_decimal_ull(m, " ", mm->end_data);
 590                 seq_put_decimal_ull(m, " ", mm->start_brk);
 591                 seq_put_decimal_ull(m, " ", mm->arg_start);
 592                 seq_put_decimal_ull(m, " ", mm->arg_end);
 593                 seq_put_decimal_ull(m, " ", mm->env_start);
 594                 seq_put_decimal_ull(m, " ", mm->env_end);
 595         } else
 596                 seq_puts(m, " 0 0 0 0 0 0 0");
 597
 598         if (permitted)
 599                 seq_put_decimal_ll(m, " ", task->exit_code);
 600         else
 601                 seq_puts(m, " 0");
 602
 603         seq_putc(m, '\n');
 604         if (mm)
 605                 mmput(mm);
 606         return 0;
 607 }
 608
 609 int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
 610                         struct pid *pid, struct task_struct *task)
 611 {
 612         return do_task_stat(m, ns, pid, task, 0);
 613 }
 614
 615 int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
 616                         struct pid *pid, struct task_struct *task)
 617 {
 618         return do_task_stat(m, ns, pid, task, 1);
 619 }
 620
 621 int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
 622                         struct pid *pid, struct task_struct *task)
 623 {
 624         unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0;
 625         struct mm_struct *mm = get_task_mm(task);
 626
 627         if (mm) {
 628                 size = task_statm(mm, &shared, &text, &data, &resident);
 629                 mmput(mm);
 630         }
 631         /*
 632          * For quick read, open code by putting numbers directly
 633          * expected format is
 634          * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
 635          *               size, resident, shared, text, data);
 636          */
 637         seq_put_decimal_ull(m, "", size);
 638         seq_put_decimal_ull(m, " ", resident);
 639         seq_put_decimal_ull(m, " ", shared);
 640         seq_put_decimal_ull(m, " ", text);
 641         seq_put_decimal_ull(m, " ", 0);
 642         seq_put_decimal_ull(m, " ", data);
 643         seq_put_decimal_ull(m, " ", 0);
 644         seq_putc(m, '\n');
 645
 646         return 0;
 647 }
 648
 649 #ifdef CONFIG_PROC_CHILDREN
 650 static struct pid *
 651 get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
 652 {
 653         struct task_struct *start, *task;
 654         struct pid *pid = NULL;
 655
 656         read_lock(&tasklist_lock);
 657
 658         start = pid_task(proc_pid(inode), PIDTYPE_PID);
 659         if (!start)
 660                 goto out;
 661
 662         /*
 663          * Lets try to continue searching first, this gives
 664          * us significant speedup on children-rich processes.
 665          */
 666         if (pid_prev) {
 667                 task = pid_task(pid_prev, PIDTYPE_PID);
 668                 if (task && task->real_parent == start &&
 669                     !(list_empty(&task->sibling))) {
 670                         if (list_is_last(&task->sibling, &start->children))
 671                                 goto out;
 672                         task = list_first_entry(&task->sibling,
 673                                                 struct task_struct, sibling);
 674                         pid = get_pid(task_pid(task));
 675                         goto out;
 676                 }
 677         }
 678
 679         /*
 680          * Slow search case.
 681          *
 682          * We might miss some children here if children
 683          * are exited while we were not holding the lock,
 684          * but it was never promised to be accurate that
 685          * much.
 686          *
 687          * "Just suppose that the parent sleeps, but N children
 688          *  exit after we printed their tids. Now the slow paths
 689          *  skips N extra children, we miss N tasks." (c)
 690          *
 691          * So one need to stop or freeze the leader and all
 692          * its children to get a precise result.
 693          */
 694         list_for_each_entry(task, &start->children, sibling) {
 695                 if (pos-- == 0) {
 696                         pid = get_pid(task_pid(task));
 697                         break;
 698                 }
 699         }
 700
 701 out:
 702         read_unlock(&tasklist_lock);
 703         return pid;
 704 }
 705
 706 static int children_seq_show(struct seq_file *seq, void *v)
 707 {
 708         struct inode *inode = seq->private;
 709         pid_t pid;
 710
 711         pid = pid_nr_ns(v, inode->i_sb->s_fs_info);
 712         seq_printf(seq, "%d ", pid);
 713
 714         return 0;
 715 }
 716
 717 static void *children_seq_start(struct seq_file *seq, loff_t *pos)
 718 {
 719         return get_children_pid(seq->private, NULL, *pos);
 720 }
 721
 722 static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 723 {
 724         struct pid *pid;
 725
 726         pid = get_children_pid(seq->private, v, *pos + 1);
 727         put_pid(v);
 728
 729         ++*pos;
 730         return pid;
 731 }
 732
 733 static void children_seq_stop(struct seq_file *seq, void *v)
 734 {
 735         put_pid(v);
 736 }
 737
 738 static const struct seq_operations children_seq_ops = {
 739         .start  = children_seq_start,
 740         .next   = children_seq_next,
 741         .stop   = children_seq_stop,
 742         .show   = children_seq_show,
 743 };
 744
 745 static int children_seq_open(struct inode *inode, struct file *file)
 746 {
 747         struct seq_file *m;
 748         int ret;
 749
 750         ret = seq_open(file, &children_seq_ops);
 751         if (ret)
 752                 return ret;
 753
 754         m = file->private_data;
 755         m->private = inode;
 756
 757         return ret;
 758 }
 759
 760 int children_seq_release(struct inode *inode, struct file *file)
 761 {
 762         seq_release(inode, file);
 763         return 0;
 764 }
 765
 766 const struct file_operations proc_tid_children_operations = {
 767         .open    = children_seq_open,
 768         .read    = seq_read,
 769         .llseek  = seq_lseek,
 770         .release = children_seq_release,
 771 };
 772 #endif /* CONFIG_PROC_CHILDREN */