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TOMOYO Linux Cross Reference
Linux/fs/proc/base.c

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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/swap.h>
 67 #include <linux/rcupdate.h>
 68 #include <linux/kallsyms.h>
 69 #include <linux/stacktrace.h>
 70 #include <linux/resource.h>
 71 #include <linux/module.h>
 72 #include <linux/mount.h>
 73 #include <linux/security.h>
 74 #include <linux/ptrace.h>
 75 #include <linux/tracehook.h>
 76 #include <linux/printk.h>
 77 #include <linux/cgroup.h>
 78 #include <linux/cpuset.h>
 79 #include <linux/audit.h>
 80 #include <linux/poll.h>
 81 #include <linux/nsproxy.h>
 82 #include <linux/oom.h>
 83 #include <linux/elf.h>
 84 #include <linux/pid_namespace.h>
 85 #include <linux/user_namespace.h>
 86 #include <linux/fs_struct.h>
 87 #include <linux/slab.h>
 88 #include <linux/flex_array.h>
 89 #include <linux/posix-timers.h>
 90 #ifdef CONFIG_HARDWALL
 91 #include <asm/hardwall.h>
 92 #endif
 93 #include <trace/events/oom.h>
 94 #include "internal.h"
 95 #include "fd.h"
 96 
 97 /* NOTE:
 98  *      Implementing inode permission operations in /proc is almost
 99  *      certainly an error.  Permission checks need to happen during
100  *      each system call not at open time.  The reason is that most of
101  *      what we wish to check for permissions in /proc varies at runtime.
102  *
103  *      The classic example of a problem is opening file descriptors
104  *      in /proc for a task before it execs a suid executable.
105  */
106 
107 struct pid_entry {
108         const char *name;
109         int len;
110         umode_t mode;
111         const struct inode_operations *iop;
112         const struct file_operations *fop;
113         union proc_op op;
114 };
115 
116 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
117         .name = (NAME),                                 \
118         .len  = sizeof(NAME) - 1,                       \
119         .mode = MODE,                                   \
120         .iop  = IOP,                                    \
121         .fop  = FOP,                                    \
122         .op   = OP,                                     \
123 }
124 
125 #define DIR(NAME, MODE, iops, fops)     \
126         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
127 #define LNK(NAME, get_link)                                     \
128         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
129                 &proc_pid_link_inode_operations, NULL,          \
130                 { .proc_get_link = get_link } )
131 #define REG(NAME, MODE, fops)                           \
132         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
133 #define ONE(NAME, MODE, show)                           \
134         NOD(NAME, (S_IFREG|(MODE)),                     \
135                 NULL, &proc_single_file_operations,     \
136                 { .proc_show = show } )
137 
138 /*
139  * Count the number of hardlinks for the pid_entry table, excluding the .
140  * and .. links.
141  */
142 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
143         unsigned int n)
144 {
145         unsigned int i;
146         unsigned int count;
147 
148         count = 0;
149         for (i = 0; i < n; ++i) {
150                 if (S_ISDIR(entries[i].mode))
151                         ++count;
152         }
153 
154         return count;
155 }
156 
157 static int get_task_root(struct task_struct *task, struct path *root)
158 {
159         int result = -ENOENT;
160 
161         task_lock(task);
162         if (task->fs) {
163                 get_fs_root(task->fs, root);
164                 result = 0;
165         }
166         task_unlock(task);
167         return result;
168 }
169 
170 static int proc_cwd_link(struct dentry *dentry, struct path *path)
171 {
172         struct task_struct *task = get_proc_task(d_inode(dentry));
173         int result = -ENOENT;
174 
175         if (task) {
176                 task_lock(task);
177                 if (task->fs) {
178                         get_fs_pwd(task->fs, path);
179                         result = 0;
180                 }
181                 task_unlock(task);
182                 put_task_struct(task);
183         }
184         return result;
185 }
186 
187 static int proc_root_link(struct dentry *dentry, struct path *path)
188 {
189         struct task_struct *task = get_proc_task(d_inode(dentry));
190         int result = -ENOENT;
191 
192         if (task) {
193                 result = get_task_root(task, path);
194                 put_task_struct(task);
195         }
196         return result;
197 }
198 
199 static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
200                                      size_t _count, loff_t *pos)
201 {
202         struct task_struct *tsk;
203         struct mm_struct *mm;
204         char *page;
205         unsigned long count = _count;
206         unsigned long arg_start, arg_end, env_start, env_end;
207         unsigned long len1, len2, len;
208         unsigned long p;
209         char c;
210         ssize_t rv;
211 
212         BUG_ON(*pos < 0);
213 
214         tsk = get_proc_task(file_inode(file));
215         if (!tsk)
216                 return -ESRCH;
217         mm = get_task_mm(tsk);
218         put_task_struct(tsk);
219         if (!mm)
220                 return 0;
221         /* Check if process spawned far enough to have cmdline. */
222         if (!mm->env_end) {
223                 rv = 0;
224                 goto out_mmput;
225         }
226 
227         page = (char *)__get_free_page(GFP_TEMPORARY);
228         if (!page) {
229                 rv = -ENOMEM;
230                 goto out_mmput;
231         }
232 
233         down_read(&mm->mmap_sem);
234         arg_start = mm->arg_start;
235         arg_end = mm->arg_end;
236         env_start = mm->env_start;
237         env_end = mm->env_end;
238         up_read(&mm->mmap_sem);
239 
240         BUG_ON(arg_start > arg_end);
241         BUG_ON(env_start > env_end);
242 
243         len1 = arg_end - arg_start;
244         len2 = env_end - env_start;
245 
246         /* Empty ARGV. */
247         if (len1 == 0) {
248                 rv = 0;
249                 goto out_free_page;
250         }
251         /*
252          * Inherently racy -- command line shares address space
253          * with code and data.
254          */
255         rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0);
256         if (rv <= 0)
257                 goto out_free_page;
258 
259         rv = 0;
260 
261         if (c == '\0') {
262                 /* Command line (set of strings) occupies whole ARGV. */
263                 if (len1 <= *pos)
264                         goto out_free_page;
265 
266                 p = arg_start + *pos;
267                 len = len1 - *pos;
268                 while (count > 0 && len > 0) {
269                         unsigned int _count;
270                         int nr_read;
271 
272                         _count = min3(count, len, PAGE_SIZE);
273                         nr_read = access_remote_vm(mm, p, page, _count, 0);
274                         if (nr_read < 0)
275                                 rv = nr_read;
276                         if (nr_read <= 0)
277                                 goto out_free_page;
278 
279                         if (copy_to_user(buf, page, nr_read)) {
280                                 rv = -EFAULT;
281                                 goto out_free_page;
282                         }
283 
284                         p       += nr_read;
285                         len     -= nr_read;
286                         buf     += nr_read;
287                         count   -= nr_read;
288                         rv      += nr_read;
289                 }
290         } else {
291                 /*
292                  * Command line (1 string) occupies ARGV and maybe
293                  * extends into ENVP.
294                  */
295                 if (len1 + len2 <= *pos)
296                         goto skip_argv_envp;
297                 if (len1 <= *pos)
298                         goto skip_argv;
299 
300                 p = arg_start + *pos;
301                 len = len1 - *pos;
302                 while (count > 0 && len > 0) {
303                         unsigned int _count, l;
304                         int nr_read;
305                         bool final;
306 
307                         _count = min3(count, len, PAGE_SIZE);
308                         nr_read = access_remote_vm(mm, p, page, _count, 0);
309                         if (nr_read < 0)
310                                 rv = nr_read;
311                         if (nr_read <= 0)
312                                 goto out_free_page;
313 
314                         /*
315                          * Command line can be shorter than whole ARGV
316                          * even if last "marker" byte says it is not.
317                          */
318                         final = false;
319                         l = strnlen(page, nr_read);
320                         if (l < nr_read) {
321                                 nr_read = l;
322                                 final = true;
323                         }
324 
325                         if (copy_to_user(buf, page, nr_read)) {
326                                 rv = -EFAULT;
327                                 goto out_free_page;
328                         }
329 
330                         p       += nr_read;
331                         len     -= nr_read;
332                         buf     += nr_read;
333                         count   -= nr_read;
334                         rv      += nr_read;
335 
336                         if (final)
337                                 goto out_free_page;
338                 }
339 skip_argv:
340                 /*
341                  * Command line (1 string) occupies ARGV and
342                  * extends into ENVP.
343                  */
344                 if (len1 <= *pos) {
345                         p = env_start + *pos - len1;
346                         len = len1 + len2 - *pos;
347                 } else {
348                         p = env_start;
349                         len = len2;
350                 }
351                 while (count > 0 && len > 0) {
352                         unsigned int _count, l;
353                         int nr_read;
354                         bool final;
355 
356                         _count = min3(count, len, PAGE_SIZE);
357                         nr_read = access_remote_vm(mm, p, page, _count, 0);
358                         if (nr_read < 0)
359                                 rv = nr_read;
360                         if (nr_read <= 0)
361                                 goto out_free_page;
362 
363                         /* Find EOS. */
364                         final = false;
365                         l = strnlen(page, nr_read);
366                         if (l < nr_read) {
367                                 nr_read = l;
368                                 final = true;
369                         }
370 
371                         if (copy_to_user(buf, page, nr_read)) {
372                                 rv = -EFAULT;
373                                 goto out_free_page;
374                         }
375 
376                         p       += nr_read;
377                         len     -= nr_read;
378                         buf     += nr_read;
379                         count   -= nr_read;
380                         rv      += nr_read;
381 
382                         if (final)
383                                 goto out_free_page;
384                 }
385 skip_argv_envp:
386                 ;
387         }
388 
389 out_free_page:
390         free_page((unsigned long)page);
391 out_mmput:
392         mmput(mm);
393         if (rv > 0)
394                 *pos += rv;
395         return rv;
396 }
397 
398 static const struct file_operations proc_pid_cmdline_ops = {
399         .read   = proc_pid_cmdline_read,
400         .llseek = generic_file_llseek,
401 };
402 
403 static int proc_pid_auxv(struct seq_file *m, struct pid_namespace *ns,
404                          struct pid *pid, struct task_struct *task)
405 {
406         struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
407         if (mm && !IS_ERR(mm)) {
408                 unsigned int nwords = 0;
409                 do {
410                         nwords += 2;
411                 } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
412                 seq_write(m, mm->saved_auxv, nwords * sizeof(mm->saved_auxv[0]));
413                 mmput(mm);
414                 return 0;
415         } else
416                 return PTR_ERR(mm);
417 }
418 
419 
420 #ifdef CONFIG_KALLSYMS
421 /*
422  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
423  * Returns the resolved symbol.  If that fails, simply return the address.
424  */
425 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
426                           struct pid *pid, struct task_struct *task)
427 {
428         unsigned long wchan;
429         char symname[KSYM_NAME_LEN];
430 
431         wchan = get_wchan(task);
432 
433         if (wchan && ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)
434                         && !lookup_symbol_name(wchan, symname))
435                 seq_printf(m, "%s", symname);
436         else
437                 seq_putc(m, '');
438 
439         return 0;
440 }
441 #endif /* CONFIG_KALLSYMS */
442 
443 static int lock_trace(struct task_struct *task)
444 {
445         int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
446         if (err)
447                 return err;
448         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
449                 mutex_unlock(&task->signal->cred_guard_mutex);
450                 return -EPERM;
451         }
452         return 0;
453 }
454 
455 static void unlock_trace(struct task_struct *task)
456 {
457         mutex_unlock(&task->signal->cred_guard_mutex);
458 }
459 
460 #ifdef CONFIG_STACKTRACE
461 
462 #define MAX_STACK_TRACE_DEPTH   64
463 
464 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
465                           struct pid *pid, struct task_struct *task)
466 {
467         struct stack_trace trace;
468         unsigned long *entries;
469         int err;
470         int i;
471 
472         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
473         if (!entries)
474                 return -ENOMEM;
475 
476         trace.nr_entries        = 0;
477         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
478         trace.entries           = entries;
479         trace.skip              = 0;
480 
481         err = lock_trace(task);
482         if (!err) {
483                 save_stack_trace_tsk(task, &trace);
484 
485                 for (i = 0; i < trace.nr_entries; i++) {
486                         seq_printf(m, "[<%pK>] %pS\n",
487                                    (void *)entries[i], (void *)entries[i]);
488                 }
489                 unlock_trace(task);
490         }
491         kfree(entries);
492 
493         return err;
494 }
495 #endif
496 
497 #ifdef CONFIG_SCHED_INFO
498 /*
499  * Provides /proc/PID/schedstat
500  */
501 static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
502                               struct pid *pid, struct task_struct *task)
503 {
504         if (unlikely(!sched_info_on()))
505                 seq_printf(m, "0 0 0\n");
506         else
507                 seq_printf(m, "%llu %llu %lu\n",
508                    (unsigned long long)task->se.sum_exec_runtime,
509                    (unsigned long long)task->sched_info.run_delay,
510                    task->sched_info.pcount);
511 
512         return 0;
513 }
514 #endif
515 
516 #ifdef CONFIG_LATENCYTOP
517 static int lstats_show_proc(struct seq_file *m, void *v)
518 {
519         int i;
520         struct inode *inode = m->private;
521         struct task_struct *task = get_proc_task(inode);
522 
523         if (!task)
524                 return -ESRCH;
525         seq_puts(m, "Latency Top version : v0.1\n");
526         for (i = 0; i < 32; i++) {
527                 struct latency_record *lr = &task->latency_record[i];
528                 if (lr->backtrace[0]) {
529                         int q;
530                         seq_printf(m, "%i %li %li",
531                                    lr->count, lr->time, lr->max);
532                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
533                                 unsigned long bt = lr->backtrace[q];
534                                 if (!bt)
535                                         break;
536                                 if (bt == ULONG_MAX)
537                                         break;
538                                 seq_printf(m, " %ps", (void *)bt);
539                         }
540                         seq_putc(m, '\n');
541                 }
542 
543         }
544         put_task_struct(task);
545         return 0;
546 }
547 
548 static int lstats_open(struct inode *inode, struct file *file)
549 {
550         return single_open(file, lstats_show_proc, inode);
551 }
552 
553 static ssize_t lstats_write(struct file *file, const char __user *buf,
554                             size_t count, loff_t *offs)
555 {
556         struct task_struct *task = get_proc_task(file_inode(file));
557 
558         if (!task)
559                 return -ESRCH;
560         clear_all_latency_tracing(task);
561         put_task_struct(task);
562 
563         return count;
564 }
565 
566 static const struct file_operations proc_lstats_operations = {
567         .open           = lstats_open,
568         .read           = seq_read,
569         .write          = lstats_write,
570         .llseek         = seq_lseek,
571         .release        = single_release,
572 };
573 
574 #endif
575 
576 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
577                           struct pid *pid, struct task_struct *task)
578 {
579         unsigned long totalpages = totalram_pages + total_swap_pages;
580         unsigned long points = 0;
581 
582         points = oom_badness(task, NULL, NULL, totalpages) *
583                                         1000 / totalpages;
584         seq_printf(m, "%lu\n", points);
585 
586         return 0;
587 }
588 
589 struct limit_names {
590         const char *name;
591         const char *unit;
592 };
593 
594 static const struct limit_names lnames[RLIM_NLIMITS] = {
595         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
596         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
597         [RLIMIT_DATA] = {"Max data size", "bytes"},
598         [RLIMIT_STACK] = {"Max stack size", "bytes"},
599         [RLIMIT_CORE] = {"Max core file size", "bytes"},
600         [RLIMIT_RSS] = {"Max resident set", "bytes"},
601         [RLIMIT_NPROC] = {"Max processes", "processes"},
602         [RLIMIT_NOFILE] = {"Max open files", "files"},
603         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
604         [RLIMIT_AS] = {"Max address space", "bytes"},
605         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
606         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
607         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
608         [RLIMIT_NICE] = {"Max nice priority", NULL},
609         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
610         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
611 };
612 
613 /* Display limits for a process */
614 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
615                            struct pid *pid, struct task_struct *task)
616 {
617         unsigned int i;
618         unsigned long flags;
619 
620         struct rlimit rlim[RLIM_NLIMITS];
621 
622         if (!lock_task_sighand(task, &flags))
623                 return 0;
624         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
625         unlock_task_sighand(task, &flags);
626 
627         /*
628          * print the file header
629          */
630        seq_printf(m, "%-25s %-20s %-20s %-10s\n",
631                   "Limit", "Soft Limit", "Hard Limit", "Units");
632 
633         for (i = 0; i < RLIM_NLIMITS; i++) {
634                 if (rlim[i].rlim_cur == RLIM_INFINITY)
635                         seq_printf(m, "%-25s %-20s ",
636                                    lnames[i].name, "unlimited");
637                 else
638                         seq_printf(m, "%-25s %-20lu ",
639                                    lnames[i].name, rlim[i].rlim_cur);
640 
641                 if (rlim[i].rlim_max == RLIM_INFINITY)
642                         seq_printf(m, "%-20s ", "unlimited");
643                 else
644                         seq_printf(m, "%-20lu ", rlim[i].rlim_max);
645 
646                 if (lnames[i].unit)
647                         seq_printf(m, "%-10s\n", lnames[i].unit);
648                 else
649                         seq_putc(m, '\n');
650         }
651 
652         return 0;
653 }
654 
655 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
656 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
657                             struct pid *pid, struct task_struct *task)
658 {
659         long nr;
660         unsigned long args[6], sp, pc;
661         int res;
662 
663         res = lock_trace(task);
664         if (res)
665                 return res;
666 
667         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
668                 seq_puts(m, "running\n");
669         else if (nr < 0)
670                 seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
671         else
672                 seq_printf(m,
673                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
674                        nr,
675                        args[0], args[1], args[2], args[3], args[4], args[5],
676                        sp, pc);
677         unlock_trace(task);
678 
679         return 0;
680 }
681 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
682 
683 /************************************************************************/
684 /*                       Here the fs part begins                        */
685 /************************************************************************/
686 
687 /* permission checks */
688 static int proc_fd_access_allowed(struct inode *inode)
689 {
690         struct task_struct *task;
691         int allowed = 0;
692         /* Allow access to a task's file descriptors if it is us or we
693          * may use ptrace attach to the process and find out that
694          * information.
695          */
696         task = get_proc_task(inode);
697         if (task) {
698                 allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
699                 put_task_struct(task);
700         }
701         return allowed;
702 }
703 
704 int proc_setattr(struct dentry *dentry, struct iattr *attr)
705 {
706         int error;
707         struct inode *inode = d_inode(dentry);
708 
709         if (attr->ia_valid & ATTR_MODE)
710                 return -EPERM;
711 
712         error = inode_change_ok(inode, attr);
713         if (error)
714                 return error;
715 
716         setattr_copy(inode, attr);
717         mark_inode_dirty(inode);
718         return 0;
719 }
720 
721 /*
722  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
723  * or euid/egid (for hide_pid_min=2)?
724  */
725 static bool has_pid_permissions(struct pid_namespace *pid,
726                                  struct task_struct *task,
727                                  int hide_pid_min)
728 {
729         if (pid->hide_pid < hide_pid_min)
730                 return true;
731         if (in_group_p(pid->pid_gid))
732                 return true;
733         return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
734 }
735 
736 
737 static int proc_pid_permission(struct inode *inode, int mask)
738 {
739         struct pid_namespace *pid = inode->i_sb->s_fs_info;
740         struct task_struct *task;
741         bool has_perms;
742 
743         task = get_proc_task(inode);
744         if (!task)
745                 return -ESRCH;
746         has_perms = has_pid_permissions(pid, task, 1);
747         put_task_struct(task);
748 
749         if (!has_perms) {
750                 if (pid->hide_pid == 2) {
751                         /*
752                          * Let's make getdents(), stat(), and open()
753                          * consistent with each other.  If a process
754                          * may not stat() a file, it shouldn't be seen
755                          * in procfs at all.
756                          */
757                         return -ENOENT;
758                 }
759 
760                 return -EPERM;
761         }
762         return generic_permission(inode, mask);
763 }
764 
765 
766 
767 static const struct inode_operations proc_def_inode_operations = {
768         .setattr        = proc_setattr,
769 };
770 
771 static int proc_single_show(struct seq_file *m, void *v)
772 {
773         struct inode *inode = m->private;
774         struct pid_namespace *ns;
775         struct pid *pid;
776         struct task_struct *task;
777         int ret;
778 
779         ns = inode->i_sb->s_fs_info;
780         pid = proc_pid(inode);
781         task = get_pid_task(pid, PIDTYPE_PID);
782         if (!task)
783                 return -ESRCH;
784 
785         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
786 
787         put_task_struct(task);
788         return ret;
789 }
790 
791 static int proc_single_open(struct inode *inode, struct file *filp)
792 {
793         return single_open(filp, proc_single_show, inode);
794 }
795 
796 static const struct file_operations proc_single_file_operations = {
797         .open           = proc_single_open,
798         .read           = seq_read,
799         .llseek         = seq_lseek,
800         .release        = single_release,
801 };
802 
803 
804 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
805 {
806         struct task_struct *task = get_proc_task(inode);
807         struct mm_struct *mm = ERR_PTR(-ESRCH);
808 
809         if (task) {
810                 mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
811                 put_task_struct(task);
812 
813                 if (!IS_ERR_OR_NULL(mm)) {
814                         /* ensure this mm_struct can't be freed */
815                         atomic_inc(&mm->mm_count);
816                         /* but do not pin its memory */
817                         mmput(mm);
818                 }
819         }
820 
821         return mm;
822 }
823 
824 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
825 {
826         struct mm_struct *mm = proc_mem_open(inode, mode);
827 
828         if (IS_ERR(mm))
829                 return PTR_ERR(mm);
830 
831         file->private_data = mm;
832         return 0;
833 }
834 
835 static int mem_open(struct inode *inode, struct file *file)
836 {
837         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
838 
839         /* OK to pass negative loff_t, we can catch out-of-range */
840         file->f_mode |= FMODE_UNSIGNED_OFFSET;
841 
842         return ret;
843 }
844 
845 static ssize_t mem_rw(struct file *file, char __user *buf,
846                         size_t count, loff_t *ppos, int write)
847 {
848         struct mm_struct *mm = file->private_data;
849         unsigned long addr = *ppos;
850         ssize_t copied;
851         char *page;
852 
853         if (!mm)
854                 return 0;
855 
856         page = (char *)__get_free_page(GFP_TEMPORARY);
857         if (!page)
858                 return -ENOMEM;
859 
860         copied = 0;
861         if (!atomic_inc_not_zero(&mm->mm_users))
862                 goto free;
863 
864         while (count > 0) {
865                 int this_len = min_t(int, count, PAGE_SIZE);
866 
867                 if (write && copy_from_user(page, buf, this_len)) {
868                         copied = -EFAULT;
869                         break;
870                 }
871 
872                 this_len = access_remote_vm(mm, addr, page, this_len, write);
873                 if (!this_len) {
874                         if (!copied)
875                                 copied = -EIO;
876                         break;
877                 }
878 
879                 if (!write && copy_to_user(buf, page, this_len)) {
880                         copied = -EFAULT;
881                         break;
882                 }
883 
884                 buf += this_len;
885                 addr += this_len;
886                 copied += this_len;
887                 count -= this_len;
888         }
889         *ppos = addr;
890 
891         mmput(mm);
892 free:
893         free_page((unsigned long) page);
894         return copied;
895 }
896 
897 static ssize_t mem_read(struct file *file, char __user *buf,
898                         size_t count, loff_t *ppos)
899 {
900         return mem_rw(file, buf, count, ppos, 0);
901 }
902 
903 static ssize_t mem_write(struct file *file, const char __user *buf,
904                          size_t count, loff_t *ppos)
905 {
906         return mem_rw(file, (char __user*)buf, count, ppos, 1);
907 }
908 
909 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
910 {
911         switch (orig) {
912         case 0:
913                 file->f_pos = offset;
914                 break;
915         case 1:
916                 file->f_pos += offset;
917                 break;
918         default:
919                 return -EINVAL;
920         }
921         force_successful_syscall_return();
922         return file->f_pos;
923 }
924 
925 static int mem_release(struct inode *inode, struct file *file)
926 {
927         struct mm_struct *mm = file->private_data;
928         if (mm)
929                 mmdrop(mm);
930         return 0;
931 }
932 
933 static const struct file_operations proc_mem_operations = {
934         .llseek         = mem_lseek,
935         .read           = mem_read,
936         .write          = mem_write,
937         .open           = mem_open,
938         .release        = mem_release,
939 };
940 
941 static int environ_open(struct inode *inode, struct file *file)
942 {
943         return __mem_open(inode, file, PTRACE_MODE_READ);
944 }
945 
946 static ssize_t environ_read(struct file *file, char __user *buf,
947                         size_t count, loff_t *ppos)
948 {
949         char *page;
950         unsigned long src = *ppos;
951         int ret = 0;
952         struct mm_struct *mm = file->private_data;
953         unsigned long env_start, env_end;
954 
955         /* Ensure the process spawned far enough to have an environment. */
956         if (!mm || !mm->env_end)
957                 return 0;
958 
959         page = (char *)__get_free_page(GFP_TEMPORARY);
960         if (!page)
961                 return -ENOMEM;
962 
963         ret = 0;
964         if (!atomic_inc_not_zero(&mm->mm_users))
965                 goto free;
966 
967         down_read(&mm->mmap_sem);
968         env_start = mm->env_start;
969         env_end = mm->env_end;
970         up_read(&mm->mmap_sem);
971 
972         while (count > 0) {
973                 size_t this_len, max_len;
974                 int retval;
975 
976                 if (src >= (env_end - env_start))
977                         break;
978 
979                 this_len = env_end - (env_start + src);
980 
981                 max_len = min_t(size_t, PAGE_SIZE, count);
982                 this_len = min(max_len, this_len);
983 
984                 retval = access_remote_vm(mm, (env_start + src),
985                         page, this_len, 0);
986 
987                 if (retval <= 0) {
988                         ret = retval;
989                         break;
990                 }
991 
992                 if (copy_to_user(buf, page, retval)) {
993                         ret = -EFAULT;
994                         break;
995                 }
996 
997                 ret += retval;
998                 src += retval;
999                 buf += retval;
1000                 count -= retval;
1001         }
1002         *ppos = src;
1003         mmput(mm);
1004 
1005 free:
1006         free_page((unsigned long) page);
1007         return ret;
1008 }
1009 
1010 static const struct file_operations proc_environ_operations = {
1011         .open           = environ_open,
1012         .read           = environ_read,
1013         .llseek         = generic_file_llseek,
1014         .release        = mem_release,
1015 };
1016 
1017 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1018                             loff_t *ppos)
1019 {
1020         struct task_struct *task = get_proc_task(file_inode(file));
1021         char buffer[PROC_NUMBUF];
1022         int oom_adj = OOM_ADJUST_MIN;
1023         size_t len;
1024 
1025         if (!task)
1026                 return -ESRCH;
1027         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1028                 oom_adj = OOM_ADJUST_MAX;
1029         else
1030                 oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1031                           OOM_SCORE_ADJ_MAX;
1032         put_task_struct(task);
1033         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1034         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1035 }
1036 
1037 static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1038 {
1039         static DEFINE_MUTEX(oom_adj_mutex);
1040         struct mm_struct *mm = NULL;
1041         struct task_struct *task;
1042         int err = 0;
1043 
1044         task = get_proc_task(file_inode(file));
1045         if (!task)
1046                 return -ESRCH;
1047 
1048         mutex_lock(&oom_adj_mutex);
1049         if (legacy) {
1050                 if (oom_adj < task->signal->oom_score_adj &&
1051                                 !capable(CAP_SYS_RESOURCE)) {
1052                         err = -EACCES;
1053                         goto err_unlock;
1054                 }
1055                 /*
1056                  * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1057                  * /proc/pid/oom_score_adj instead.
1058                  */
1059                 pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1060                           current->comm, task_pid_nr(current), task_pid_nr(task),
1061                           task_pid_nr(task));
1062         } else {
1063                 if ((short)oom_adj < task->signal->oom_score_adj_min &&
1064                                 !capable(CAP_SYS_RESOURCE)) {
1065                         err = -EACCES;
1066                         goto err_unlock;
1067                 }
1068         }
1069 
1070         /*
1071          * Make sure we will check other processes sharing the mm if this is
1072          * not vfrok which wants its own oom_score_adj.
1073          * pin the mm so it doesn't go away and get reused after task_unlock
1074          */
1075         if (!task->vfork_done) {
1076                 struct task_struct *p = find_lock_task_mm(task);
1077 
1078                 if (p) {
1079                         if (atomic_read(&p->mm->mm_users) > 1) {
1080                                 mm = p->mm;
1081                                 atomic_inc(&mm->mm_count);
1082                         }
1083                         task_unlock(p);
1084                 }
1085         }
1086 
1087         task->signal->oom_score_adj = oom_adj;
1088         if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1089                 task->signal->oom_score_adj_min = (short)oom_adj;
1090         trace_oom_score_adj_update(task);
1091 
1092         if (mm) {
1093                 struct task_struct *p;
1094 
1095                 rcu_read_lock();
1096                 for_each_process(p) {
1097                         if (same_thread_group(task, p))
1098                                 continue;
1099 
1100                         /* do not touch kernel threads or the global init */
1101                         if (p->flags & PF_KTHREAD || is_global_init(p))
1102                                 continue;
1103 
1104                         task_lock(p);
1105                         if (!p->vfork_done && process_shares_mm(p, mm)) {
1106                                 pr_info("updating oom_score_adj for %d (%s) from %d to %d because it shares mm with %d (%s). Report if this is unexpected.\n",
1107                                                 task_pid_nr(p), p->comm,
1108                                                 p->signal->oom_score_adj, oom_adj,
1109                                                 task_pid_nr(task), task->comm);
1110                                 p->signal->oom_score_adj = oom_adj;
1111                                 if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1112                                         p->signal->oom_score_adj_min = (short)oom_adj;
1113                         }
1114                         task_unlock(p);
1115                 }
1116                 rcu_read_unlock();
1117                 mmdrop(mm);
1118         }
1119 err_unlock:
1120         mutex_unlock(&oom_adj_mutex);
1121         put_task_struct(task);
1122         return err;
1123 }
1124 
1125 /*
1126  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1127  * kernels.  The effective policy is defined by oom_score_adj, which has a
1128  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1129  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1130  * Processes that become oom disabled via oom_adj will still be oom disabled
1131  * with this implementation.
1132  *
1133  * oom_adj cannot be removed since existing userspace binaries use it.
1134  */
1135 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1136                              size_t count, loff_t *ppos)
1137 {
1138         char buffer[PROC_NUMBUF];
1139         int oom_adj;
1140         int err;
1141 
1142         memset(buffer, 0, sizeof(buffer));
1143         if (count > sizeof(buffer) - 1)
1144                 count = sizeof(buffer) - 1;
1145         if (copy_from_user(buffer, buf, count)) {
1146                 err = -EFAULT;
1147                 goto out;
1148         }
1149 
1150         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1151         if (err)
1152                 goto out;
1153         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1154              oom_adj != OOM_DISABLE) {
1155                 err = -EINVAL;
1156                 goto out;
1157         }
1158 
1159         /*
1160          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1161          * value is always attainable.
1162          */
1163         if (oom_adj == OOM_ADJUST_MAX)
1164                 oom_adj = OOM_SCORE_ADJ_MAX;
1165         else
1166                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1167 
1168         err = __set_oom_adj(file, oom_adj, true);
1169 out:
1170         return err < 0 ? err : count;
1171 }
1172 
1173 static const struct file_operations proc_oom_adj_operations = {
1174         .read           = oom_adj_read,
1175         .write          = oom_adj_write,
1176         .llseek         = generic_file_llseek,
1177 };
1178 
1179 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1180                                         size_t count, loff_t *ppos)
1181 {
1182         struct task_struct *task = get_proc_task(file_inode(file));
1183         char buffer[PROC_NUMBUF];
1184         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1185         size_t len;
1186 
1187         if (!task)
1188                 return -ESRCH;
1189         oom_score_adj = task->signal->oom_score_adj;
1190         put_task_struct(task);
1191         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1192         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1193 }
1194 
1195 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1196                                         size_t count, loff_t *ppos)
1197 {
1198         char buffer[PROC_NUMBUF];
1199         int oom_score_adj;
1200         int err;
1201 
1202         memset(buffer, 0, sizeof(buffer));
1203         if (count > sizeof(buffer) - 1)
1204                 count = sizeof(buffer) - 1;
1205         if (copy_from_user(buffer, buf, count)) {
1206                 err = -EFAULT;
1207                 goto out;
1208         }
1209 
1210         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1211         if (err)
1212                 goto out;
1213         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1214                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1215                 err = -EINVAL;
1216                 goto out;
1217         }
1218 
1219         err = __set_oom_adj(file, oom_score_adj, false);
1220 out:
1221         return err < 0 ? err : count;
1222 }
1223 
1224 static const struct file_operations proc_oom_score_adj_operations = {
1225         .read           = oom_score_adj_read,
1226         .write          = oom_score_adj_write,
1227         .llseek         = default_llseek,
1228 };
1229 
1230 #ifdef CONFIG_AUDITSYSCALL
1231 #define TMPBUFLEN 21
1232 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1233                                   size_t count, loff_t *ppos)
1234 {
1235         struct inode * inode = file_inode(file);
1236         struct task_struct *task = get_proc_task(inode);
1237         ssize_t length;
1238         char tmpbuf[TMPBUFLEN];
1239 
1240         if (!task)
1241                 return -ESRCH;
1242         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1243                            from_kuid(file->f_cred->user_ns,
1244                                      audit_get_loginuid(task)));
1245         put_task_struct(task);
1246         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1247 }
1248 
1249 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1250                                    size_t count, loff_t *ppos)
1251 {
1252         struct inode * inode = file_inode(file);
1253         uid_t loginuid;
1254         kuid_t kloginuid;
1255         int rv;
1256 
1257         rcu_read_lock();
1258         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1259                 rcu_read_unlock();
1260                 return -EPERM;
1261         }
1262         rcu_read_unlock();
1263 
1264         if (*ppos != 0) {
1265                 /* No partial writes. */
1266                 return -EINVAL;
1267         }
1268 
1269         rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1270         if (rv < 0)
1271                 return rv;
1272 
1273         /* is userspace tring to explicitly UNSET the loginuid? */
1274         if (loginuid == AUDIT_UID_UNSET) {
1275                 kloginuid = INVALID_UID;
1276         } else {
1277                 kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1278                 if (!uid_valid(kloginuid))
1279                         return -EINVAL;
1280         }
1281 
1282         rv = audit_set_loginuid(kloginuid);
1283         if (rv < 0)
1284                 return rv;
1285         return count;
1286 }
1287 
1288 static const struct file_operations proc_loginuid_operations = {
1289         .read           = proc_loginuid_read,
1290         .write          = proc_loginuid_write,
1291         .llseek         = generic_file_llseek,
1292 };
1293 
1294 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1295                                   size_t count, loff_t *ppos)
1296 {
1297         struct inode * inode = file_inode(file);
1298         struct task_struct *task = get_proc_task(inode);
1299         ssize_t length;
1300         char tmpbuf[TMPBUFLEN];
1301 
1302         if (!task)
1303                 return -ESRCH;
1304         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1305                                 audit_get_sessionid(task));
1306         put_task_struct(task);
1307         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1308 }
1309 
1310 static const struct file_operations proc_sessionid_operations = {
1311         .read           = proc_sessionid_read,
1312         .llseek         = generic_file_llseek,
1313 };
1314 #endif
1315 
1316 #ifdef CONFIG_FAULT_INJECTION
1317 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1318                                       size_t count, loff_t *ppos)
1319 {
1320         struct task_struct *task = get_proc_task(file_inode(file));
1321         char buffer[PROC_NUMBUF];
1322         size_t len;
1323         int make_it_fail;
1324 
1325         if (!task)
1326                 return -ESRCH;
1327         make_it_fail = task->make_it_fail;
1328         put_task_struct(task);
1329 
1330         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1331 
1332         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1333 }
1334 
1335 static ssize_t proc_fault_inject_write(struct file * file,
1336                         const char __user * buf, size_t count, loff_t *ppos)
1337 {
1338         struct task_struct *task;
1339         char buffer[PROC_NUMBUF];
1340         int make_it_fail;
1341         int rv;
1342 
1343         if (!capable(CAP_SYS_RESOURCE))
1344                 return -EPERM;
1345         memset(buffer, 0, sizeof(buffer));
1346         if (count > sizeof(buffer) - 1)
1347                 count = sizeof(buffer) - 1;
1348         if (copy_from_user(buffer, buf, count))
1349                 return -EFAULT;
1350         rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1351         if (rv < 0)
1352                 return rv;
1353         if (make_it_fail < 0 || make_it_fail > 1)
1354                 return -EINVAL;
1355 
1356         task = get_proc_task(file_inode(file));
1357         if (!task)
1358                 return -ESRCH;
1359         task->make_it_fail = make_it_fail;
1360         put_task_struct(task);
1361 
1362         return count;
1363 }
1364 
1365 static const struct file_operations proc_fault_inject_operations = {
1366         .read           = proc_fault_inject_read,
1367         .write          = proc_fault_inject_write,
1368         .llseek         = generic_file_llseek,
1369 };
1370 #endif
1371 
1372 
1373 #ifdef CONFIG_SCHED_DEBUG
1374 /*
1375  * Print out various scheduling related per-task fields:
1376  */
1377 static int sched_show(struct seq_file *m, void *v)
1378 {
1379         struct inode *inode = m->private;
1380         struct task_struct *p;
1381 
1382         p = get_proc_task(inode);
1383         if (!p)
1384                 return -ESRCH;
1385         proc_sched_show_task(p, m);
1386 
1387         put_task_struct(p);
1388 
1389         return 0;
1390 }
1391 
1392 static ssize_t
1393 sched_write(struct file *file, const char __user *buf,
1394             size_t count, loff_t *offset)
1395 {
1396         struct inode *inode = file_inode(file);
1397         struct task_struct *p;
1398 
1399         p = get_proc_task(inode);
1400         if (!p)
1401                 return -ESRCH;
1402         proc_sched_set_task(p);
1403 
1404         put_task_struct(p);
1405 
1406         return count;
1407 }
1408 
1409 static int sched_open(struct inode *inode, struct file *filp)
1410 {
1411         return single_open(filp, sched_show, inode);
1412 }
1413 
1414 static const struct file_operations proc_pid_sched_operations = {
1415         .open           = sched_open,
1416         .read           = seq_read,
1417         .write          = sched_write,
1418         .llseek         = seq_lseek,
1419         .release        = single_release,
1420 };
1421 
1422 #endif
1423 
1424 #ifdef CONFIG_SCHED_AUTOGROUP
1425 /*
1426  * Print out autogroup related information:
1427  */
1428 static int sched_autogroup_show(struct seq_file *m, void *v)
1429 {
1430         struct inode *inode = m->private;
1431         struct task_struct *p;
1432 
1433         p = get_proc_task(inode);
1434         if (!p)
1435                 return -ESRCH;
1436         proc_sched_autogroup_show_task(p, m);
1437 
1438         put_task_struct(p);
1439 
1440         return 0;
1441 }
1442 
1443 static ssize_t
1444 sched_autogroup_write(struct file *file, const char __user *buf,
1445             size_t count, loff_t *offset)
1446 {
1447         struct inode *inode = file_inode(file);
1448         struct task_struct *p;
1449         char buffer[PROC_NUMBUF];
1450         int nice;
1451         int err;
1452 
1453         memset(buffer, 0, sizeof(buffer));
1454         if (count > sizeof(buffer) - 1)
1455                 count = sizeof(buffer) - 1;
1456         if (copy_from_user(buffer, buf, count))
1457                 return -EFAULT;
1458 
1459         err = kstrtoint(strstrip(buffer), 0, &nice);
1460         if (err < 0)
1461                 return err;
1462 
1463         p = get_proc_task(inode);
1464         if (!p)
1465                 return -ESRCH;
1466 
1467         err = proc_sched_autogroup_set_nice(p, nice);
1468         if (err)
1469                 count = err;
1470 
1471         put_task_struct(p);
1472 
1473         return count;
1474 }
1475 
1476 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1477 {
1478         int ret;
1479 
1480         ret = single_open(filp, sched_autogroup_show, NULL);
1481         if (!ret) {
1482                 struct seq_file *m = filp->private_data;
1483 
1484                 m->private = inode;
1485         }
1486         return ret;
1487 }
1488 
1489 static const struct file_operations proc_pid_sched_autogroup_operations = {
1490         .open           = sched_autogroup_open,
1491         .read           = seq_read,
1492         .write          = sched_autogroup_write,
1493         .llseek         = seq_lseek,
1494         .release        = single_release,
1495 };
1496 
1497 #endif /* CONFIG_SCHED_AUTOGROUP */
1498 
1499 static ssize_t comm_write(struct file *file, const char __user *buf,
1500                                 size_t count, loff_t *offset)
1501 {
1502         struct inode *inode = file_inode(file);
1503         struct task_struct *p;
1504         char buffer[TASK_COMM_LEN];
1505         const size_t maxlen = sizeof(buffer) - 1;
1506 
1507         memset(buffer, 0, sizeof(buffer));
1508         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1509                 return -EFAULT;
1510 
1511         p = get_proc_task(inode);
1512         if (!p)
1513                 return -ESRCH;
1514 
1515         if (same_thread_group(current, p))
1516                 set_task_comm(p, buffer);
1517         else
1518                 count = -EINVAL;
1519 
1520         put_task_struct(p);
1521 
1522         return count;
1523 }
1524 
1525 static int comm_show(struct seq_file *m, void *v)
1526 {
1527         struct inode *inode = m->private;
1528         struct task_struct *p;
1529 
1530         p = get_proc_task(inode);
1531         if (!p)
1532                 return -ESRCH;
1533 
1534         task_lock(p);
1535         seq_printf(m, "%s\n", p->comm);
1536         task_unlock(p);
1537 
1538         put_task_struct(p);
1539 
1540         return 0;
1541 }
1542 
1543 static int comm_open(struct inode *inode, struct file *filp)
1544 {
1545         return single_open(filp, comm_show, inode);
1546 }
1547 
1548 static const struct file_operations proc_pid_set_comm_operations = {
1549         .open           = comm_open,
1550         .read           = seq_read,
1551         .write          = comm_write,
1552         .llseek         = seq_lseek,
1553         .release        = single_release,
1554 };
1555 
1556 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1557 {
1558         struct task_struct *task;
1559         struct file *exe_file;
1560 
1561         task = get_proc_task(d_inode(dentry));
1562         if (!task)
1563                 return -ENOENT;
1564         exe_file = get_task_exe_file(task);
1565         put_task_struct(task);
1566         if (exe_file) {
1567                 *exe_path = exe_file->f_path;
1568                 path_get(&exe_file->f_path);
1569                 fput(exe_file);
1570                 return 0;
1571         } else
1572                 return -ENOENT;
1573 }
1574 
1575 static const char *proc_pid_get_link(struct dentry *dentry,
1576                                      struct inode *inode,
1577                                      struct delayed_call *done)
1578 {
1579         struct path path;
1580         int error = -EACCES;
1581 
1582         if (!dentry)
1583                 return ERR_PTR(-ECHILD);
1584 
1585         /* Are we allowed to snoop on the tasks file descriptors? */
1586         if (!proc_fd_access_allowed(inode))
1587                 goto out;
1588 
1589         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1590         if (error)
1591                 goto out;
1592 
1593         nd_jump_link(&path);
1594         return NULL;
1595 out:
1596         return ERR_PTR(error);
1597 }
1598 
1599 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1600 {
1601         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1602         char *pathname;
1603         int len;
1604 
1605         if (!tmp)
1606                 return -ENOMEM;
1607 
1608         pathname = d_path(path, tmp, PAGE_SIZE);
1609         len = PTR_ERR(pathname);
1610         if (IS_ERR(pathname))
1611                 goto out;
1612         len = tmp + PAGE_SIZE - 1 - pathname;
1613 
1614         if (len > buflen)
1615                 len = buflen;
1616         if (copy_to_user(buffer, pathname, len))
1617                 len = -EFAULT;
1618  out:
1619         free_page((unsigned long)tmp);
1620         return len;
1621 }
1622 
1623 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1624 {
1625         int error = -EACCES;
1626         struct inode *inode = d_inode(dentry);
1627         struct path path;
1628 
1629         /* Are we allowed to snoop on the tasks file descriptors? */
1630         if (!proc_fd_access_allowed(inode))
1631                 goto out;
1632 
1633         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1634         if (error)
1635                 goto out;
1636 
1637         error = do_proc_readlink(&path, buffer, buflen);
1638         path_put(&path);
1639 out:
1640         return error;
1641 }
1642 
1643 const struct inode_operations proc_pid_link_inode_operations = {
1644         .readlink       = proc_pid_readlink,
1645         .get_link       = proc_pid_get_link,
1646         .setattr        = proc_setattr,
1647 };
1648 
1649 
1650 /* building an inode */
1651 
1652 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1653 {
1654         struct inode * inode;
1655         struct proc_inode *ei;
1656         const struct cred *cred;
1657 
1658         /* We need a new inode */
1659 
1660         inode = new_inode(sb);
1661         if (!inode)
1662                 goto out;
1663 
1664         /* Common stuff */
1665         ei = PROC_I(inode);
1666         inode->i_ino = get_next_ino();
1667         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1668         inode->i_op = &proc_def_inode_operations;
1669 
1670         /*
1671          * grab the reference to task.
1672          */
1673         ei->pid = get_task_pid(task, PIDTYPE_PID);
1674         if (!ei->pid)
1675                 goto out_unlock;
1676 
1677         if (task_dumpable(task)) {
1678                 rcu_read_lock();
1679                 cred = __task_cred(task);
1680                 inode->i_uid = cred->euid;
1681                 inode->i_gid = cred->egid;
1682                 rcu_read_unlock();
1683         }
1684         security_task_to_inode(task, inode);
1685 
1686 out:
1687         return inode;
1688 
1689 out_unlock:
1690         iput(inode);
1691         return NULL;
1692 }
1693 
1694 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1695 {
1696         struct inode *inode = d_inode(dentry);
1697         struct task_struct *task;
1698         const struct cred *cred;
1699         struct pid_namespace *pid = dentry->d_sb->s_fs_info;
1700 
1701         generic_fillattr(inode, stat);
1702 
1703         rcu_read_lock();
1704         stat->uid = GLOBAL_ROOT_UID;
1705         stat->gid = GLOBAL_ROOT_GID;
1706         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1707         if (task) {
1708                 if (!has_pid_permissions(pid, task, 2)) {
1709                         rcu_read_unlock();
1710                         /*
1711                          * This doesn't prevent learning whether PID exists,
1712                          * it only makes getattr() consistent with readdir().
1713                          */
1714                         return -ENOENT;
1715                 }
1716                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1717                     task_dumpable(task)) {
1718                         cred = __task_cred(task);
1719                         stat->uid = cred->euid;
1720                         stat->gid = cred->egid;
1721                 }
1722         }
1723         rcu_read_unlock();
1724         return 0;
1725 }
1726 
1727 /* dentry stuff */
1728 
1729 /*
1730  *      Exceptional case: normally we are not allowed to unhash a busy
1731  * directory. In this case, however, we can do it - no aliasing problems
1732  * due to the way we treat inodes.
1733  *
1734  * Rewrite the inode's ownerships here because the owning task may have
1735  * performed a setuid(), etc.
1736  *
1737  * Before the /proc/pid/status file was created the only way to read
1738  * the effective uid of a /process was to stat /proc/pid.  Reading
1739  * /proc/pid/status is slow enough that procps and other packages
1740  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1741  * made this apply to all per process world readable and executable
1742  * directories.
1743  */
1744 int pid_revalidate(struct dentry *dentry, unsigned int flags)
1745 {
1746         struct inode *inode;
1747         struct task_struct *task;
1748         const struct cred *cred;
1749 
1750         if (flags & LOOKUP_RCU)
1751                 return -ECHILD;
1752 
1753         inode = d_inode(dentry);
1754         task = get_proc_task(inode);
1755 
1756         if (task) {
1757                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1758                     task_dumpable(task)) {
1759                         rcu_read_lock();
1760                         cred = __task_cred(task);
1761                         inode->i_uid = cred->euid;
1762                         inode->i_gid = cred->egid;
1763                         rcu_read_unlock();
1764                 } else {
1765                         inode->i_uid = GLOBAL_ROOT_UID;
1766                         inode->i_gid = GLOBAL_ROOT_GID;
1767                 }
1768                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1769                 security_task_to_inode(task, inode);
1770                 put_task_struct(task);
1771                 return 1;
1772         }
1773         return 0;
1774 }
1775 
1776 static inline bool proc_inode_is_dead(struct inode *inode)
1777 {
1778         return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1779 }
1780 
1781 int pid_delete_dentry(const struct dentry *dentry)
1782 {
1783         /* Is the task we represent dead?
1784          * If so, then don't put the dentry on the lru list,
1785          * kill it immediately.
1786          */
1787         return proc_inode_is_dead(d_inode(dentry));
1788 }
1789 
1790 const struct dentry_operations pid_dentry_operations =
1791 {
1792         .d_revalidate   = pid_revalidate,
1793         .d_delete       = pid_delete_dentry,
1794 };
1795 
1796 /* Lookups */
1797 
1798 /*
1799  * Fill a directory entry.
1800  *
1801  * If possible create the dcache entry and derive our inode number and
1802  * file type from dcache entry.
1803  *
1804  * Since all of the proc inode numbers are dynamically generated, the inode
1805  * numbers do not exist until the inode is cache.  This means creating the
1806  * the dcache entry in readdir is necessary to keep the inode numbers
1807  * reported by readdir in sync with the inode numbers reported
1808  * by stat.
1809  */
1810 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1811         const char *name, int len,
1812         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1813 {
1814         struct dentry *child, *dir = file->f_path.dentry;
1815         struct qstr qname = QSTR_INIT(name, len);
1816         struct inode *inode;
1817         unsigned type;
1818         ino_t ino;
1819 
1820         child = d_hash_and_lookup(dir, &qname);
1821         if (!child) {
1822                 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1823                 child = d_alloc_parallel(dir, &qname, &wq);
1824                 if (IS_ERR(child))
1825                         goto end_instantiate;
1826                 if (d_in_lookup(child)) {
1827                         int err = instantiate(d_inode(dir), child, task, ptr);
1828                         d_lookup_done(child);
1829                         if (err < 0) {
1830                                 dput(child);
1831                                 goto end_instantiate;
1832                         }
1833                 }
1834         }
1835         inode = d_inode(child);
1836         ino = inode->i_ino;
1837         type = inode->i_mode >> 12;
1838         dput(child);
1839         return dir_emit(ctx, name, len, ino, type);
1840 
1841 end_instantiate:
1842         return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
1843 }
1844 
1845 /*
1846  * dname_to_vma_addr - maps a dentry name into two unsigned longs
1847  * which represent vma start and end addresses.
1848  */
1849 static int dname_to_vma_addr(struct dentry *dentry,
1850                              unsigned long *start, unsigned long *end)
1851 {
1852         if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
1853                 return -EINVAL;
1854 
1855         return 0;
1856 }
1857 
1858 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1859 {
1860         unsigned long vm_start, vm_end;
1861         bool exact_vma_exists = false;
1862         struct mm_struct *mm = NULL;
1863         struct task_struct *task;
1864         const struct cred *cred;
1865         struct inode *inode;
1866         int status = 0;
1867 
1868         if (flags & LOOKUP_RCU)
1869                 return -ECHILD;
1870 
1871         inode = d_inode(dentry);
1872         task = get_proc_task(inode);
1873         if (!task)
1874                 goto out_notask;
1875 
1876         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1877         if (IS_ERR_OR_NULL(mm))
1878                 goto out;
1879 
1880         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1881                 down_read(&mm->mmap_sem);
1882                 exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1883                 up_read(&mm->mmap_sem);
1884         }
1885 
1886         mmput(mm);
1887 
1888         if (exact_vma_exists) {
1889                 if (task_dumpable(task)) {
1890                         rcu_read_lock();
1891                         cred = __task_cred(task);
1892                         inode->i_uid = cred->euid;
1893                         inode->i_gid = cred->egid;
1894                         rcu_read_unlock();
1895                 } else {
1896                         inode->i_uid = GLOBAL_ROOT_UID;
1897                         inode->i_gid = GLOBAL_ROOT_GID;
1898                 }
1899                 security_task_to_inode(task, inode);
1900                 status = 1;
1901         }
1902 
1903 out:
1904         put_task_struct(task);
1905 
1906 out_notask:
1907         return status;
1908 }
1909 
1910 static const struct dentry_operations tid_map_files_dentry_operations = {
1911         .d_revalidate   = map_files_d_revalidate,
1912         .d_delete       = pid_delete_dentry,
1913 };
1914 
1915 static int map_files_get_link(struct dentry *dentry, struct path *path)
1916 {
1917         unsigned long vm_start, vm_end;
1918         struct vm_area_struct *vma;
1919         struct task_struct *task;
1920         struct mm_struct *mm;
1921         int rc;
1922 
1923         rc = -ENOENT;
1924         task = get_proc_task(d_inode(dentry));
1925         if (!task)
1926                 goto out;
1927 
1928         mm = get_task_mm(task);
1929         put_task_struct(task);
1930         if (!mm)
1931                 goto out;
1932 
1933         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
1934         if (rc)
1935                 goto out_mmput;
1936 
1937         rc = -ENOENT;
1938         down_read(&mm->mmap_sem);
1939         vma = find_exact_vma(mm, vm_start, vm_end);
1940         if (vma && vma->vm_file) {
1941                 *path = vma->vm_file->f_path;
1942                 path_get(path);
1943                 rc = 0;
1944         }
1945         up_read(&mm->mmap_sem);
1946 
1947 out_mmput:
1948         mmput(mm);
1949 out:
1950         return rc;
1951 }
1952 
1953 struct map_files_info {
1954         fmode_t         mode;
1955         unsigned long   len;
1956         unsigned char   name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
1957 };
1958 
1959 /*
1960  * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
1961  * symlinks may be used to bypass permissions on ancestor directories in the
1962  * path to the file in question.
1963  */
1964 static const char *
1965 proc_map_files_get_link(struct dentry *dentry,
1966                         struct inode *inode,
1967                         struct delayed_call *done)
1968 {
1969         if (!capable(CAP_SYS_ADMIN))
1970                 return ERR_PTR(-EPERM);
1971 
1972         return proc_pid_get_link(dentry, inode, done);
1973 }
1974 
1975 /*
1976  * Identical to proc_pid_link_inode_operations except for get_link()
1977  */
1978 static const struct inode_operations proc_map_files_link_inode_operations = {
1979         .readlink       = proc_pid_readlink,
1980         .get_link       = proc_map_files_get_link,
1981         .setattr        = proc_setattr,
1982 };
1983 
1984 static int
1985 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
1986                            struct task_struct *task, const void *ptr)
1987 {
1988         fmode_t mode = (fmode_t)(unsigned long)ptr;
1989         struct proc_inode *ei;
1990         struct inode *inode;
1991 
1992         inode = proc_pid_make_inode(dir->i_sb, task);
1993         if (!inode)
1994                 return -ENOENT;
1995 
1996         ei = PROC_I(inode);
1997         ei->op.proc_get_link = map_files_get_link;
1998 
1999         inode->i_op = &proc_map_files_link_inode_operations;
2000         inode->i_size = 64;
2001         inode->i_mode = S_IFLNK;
2002 
2003         if (mode & FMODE_READ)
2004                 inode->i_mode |= S_IRUSR;
2005         if (mode & FMODE_WRITE)
2006                 inode->i_mode |= S_IWUSR;
2007 
2008         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2009         d_add(dentry, inode);
2010 
2011         return 0;
2012 }
2013 
2014 static struct dentry *proc_map_files_lookup(struct inode *dir,
2015                 struct dentry *dentry, unsigned int flags)
2016 {
2017         unsigned long vm_start, vm_end;
2018         struct vm_area_struct *vma;
2019         struct task_struct *task;
2020         int result;
2021         struct mm_struct *mm;
2022 
2023         result = -ENOENT;
2024         task = get_proc_task(dir);
2025         if (!task)
2026                 goto out;
2027 
2028         result = -EACCES;
2029         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2030                 goto out_put_task;
2031 
2032         result = -ENOENT;
2033         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2034                 goto out_put_task;
2035 
2036         mm = get_task_mm(task);
2037         if (!mm)
2038                 goto out_put_task;
2039 
2040         down_read(&mm->mmap_sem);
2041         vma = find_exact_vma(mm, vm_start, vm_end);
2042         if (!vma)
2043                 goto out_no_vma;
2044 
2045         if (vma->vm_file)
2046                 result = proc_map_files_instantiate(dir, dentry, task,
2047                                 (void *)(unsigned long)vma->vm_file->f_mode);
2048 
2049 out_no_vma:
2050         up_read(&mm->mmap_sem);
2051         mmput(mm);
2052 out_put_task:
2053         put_task_struct(task);
2054 out:
2055         return ERR_PTR(result);
2056 }
2057 
2058 static const struct inode_operations proc_map_files_inode_operations = {
2059         .lookup         = proc_map_files_lookup,
2060         .permission     = proc_fd_permission,
2061         .setattr        = proc_setattr,
2062 };
2063 
2064 static int
2065 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2066 {
2067         struct vm_area_struct *vma;
2068         struct task_struct *task;
2069         struct mm_struct *mm;
2070         unsigned long nr_files, pos, i;
2071         struct flex_array *fa = NULL;
2072         struct map_files_info info;
2073         struct map_files_info *p;
2074         int ret;
2075 
2076         ret = -ENOENT;
2077         task = get_proc_task(file_inode(file));
2078         if (!task)
2079                 goto out;
2080 
2081         ret = -EACCES;
2082         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2083                 goto out_put_task;
2084 
2085         ret = 0;
2086         if (!dir_emit_dots(file, ctx))
2087                 goto out_put_task;
2088 
2089         mm = get_task_mm(task);
2090         if (!mm)
2091                 goto out_put_task;
2092         down_read(&mm->mmap_sem);
2093 
2094         nr_files = 0;
2095 
2096         /*
2097          * We need two passes here:
2098          *
2099          *  1) Collect vmas of mapped files with mmap_sem taken
2100          *  2) Release mmap_sem and instantiate entries
2101          *
2102          * otherwise we get lockdep complained, since filldir()
2103          * routine might require mmap_sem taken in might_fault().
2104          */
2105 
2106         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2107                 if (vma->vm_file && ++pos > ctx->pos)
2108                         nr_files++;
2109         }
2110 
2111         if (nr_files) {
2112                 fa = flex_array_alloc(sizeof(info), nr_files,
2113                                         GFP_KERNEL);
2114                 if (!fa || flex_array_prealloc(fa, 0, nr_files,
2115                                                 GFP_KERNEL)) {
2116                         ret = -ENOMEM;
2117                         if (fa)
2118                                 flex_array_free(fa);
2119                         up_read(&mm->mmap_sem);
2120                         mmput(mm);
2121                         goto out_put_task;
2122                 }
2123                 for (i = 0, vma = mm->mmap, pos = 2; vma;
2124                                 vma = vma->vm_next) {
2125                         if (!vma->vm_file)
2126                                 continue;
2127                         if (++pos <= ctx->pos)
2128                                 continue;
2129 
2130                         info.mode = vma->vm_file->f_mode;
2131                         info.len = snprintf(info.name,
2132                                         sizeof(info.name), "%lx-%lx",
2133                                         vma->vm_start, vma->vm_end);
2134                         if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2135                                 BUG();
2136                 }
2137         }
2138         up_read(&mm->mmap_sem);
2139 
2140         for (i = 0; i < nr_files; i++) {
2141                 p = flex_array_get(fa, i);
2142                 if (!proc_fill_cache(file, ctx,
2143                                       p->name, p->len,
2144                                       proc_map_files_instantiate,
2145                                       task,
2146                                       (void *)(unsigned long)p->mode))
2147                         break;
2148                 ctx->pos++;
2149         }
2150         if (fa)
2151                 flex_array_free(fa);
2152         mmput(mm);
2153 
2154 out_put_task:
2155         put_task_struct(task);
2156 out:
2157         return ret;
2158 }
2159 
2160 static const struct file_operations proc_map_files_operations = {
2161         .read           = generic_read_dir,
2162         .iterate_shared = proc_map_files_readdir,
2163         .llseek         = generic_file_llseek,
2164 };
2165 
2166 #ifdef CONFIG_CHECKPOINT_RESTORE
2167 struct timers_private {
2168         struct pid *pid;
2169         struct task_struct *task;
2170         struct sighand_struct *sighand;
2171         struct pid_namespace *ns;
2172         unsigned long flags;
2173 };
2174 
2175 static void *timers_start(struct seq_file *m, loff_t *pos)
2176 {
2177         struct timers_private *tp = m->private;
2178 
2179         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2180         if (!tp->task)
2181                 return ERR_PTR(-ESRCH);
2182 
2183         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2184         if (!tp->sighand)
2185                 return ERR_PTR(-ESRCH);
2186 
2187         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2188 }
2189 
2190 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2191 {
2192         struct timers_private *tp = m->private;
2193         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2194 }
2195 
2196 static void timers_stop(struct seq_file *m, void *v)
2197 {
2198         struct timers_private *tp = m->private;
2199 
2200         if (tp->sighand) {
2201                 unlock_task_sighand(tp->task, &tp->flags);
2202                 tp->sighand = NULL;
2203         }
2204 
2205         if (tp->task) {
2206                 put_task_struct(tp->task);
2207                 tp->task = NULL;
2208         }
2209 }
2210 
2211 static int show_timer(struct seq_file *m, void *v)
2212 {
2213         struct k_itimer *timer;
2214         struct timers_private *tp = m->private;
2215         int notify;
2216         static const char * const nstr[] = {
2217                 [SIGEV_SIGNAL] = "signal",
2218                 [SIGEV_NONE] = "none",
2219                 [SIGEV_THREAD] = "thread",
2220         };
2221 
2222         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2223         notify = timer->it_sigev_notify;
2224 
2225         seq_printf(m, "ID: %d\n", timer->it_id);
2226         seq_printf(m, "signal: %d/%p\n",
2227                    timer->sigq->info.si_signo,
2228                    timer->sigq->info.si_value.sival_ptr);
2229         seq_printf(m, "notify: %s/%s.%d\n",
2230                    nstr[notify & ~SIGEV_THREAD_ID],
2231                    (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2232                    pid_nr_ns(timer->it_pid, tp->ns));
2233         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2234 
2235         return 0;
2236 }
2237 
2238 static const struct seq_operations proc_timers_seq_ops = {
2239         .start  = timers_start,
2240         .next   = timers_next,
2241         .stop   = timers_stop,
2242         .show   = show_timer,
2243 };
2244 
2245 static int proc_timers_open(struct inode *inode, struct file *file)
2246 {
2247         struct timers_private *tp;
2248 
2249         tp = __seq_open_private(file, &proc_timers_seq_ops,
2250                         sizeof(struct timers_private));
2251         if (!tp)
2252                 return -ENOMEM;
2253 
2254         tp->pid = proc_pid(inode);
2255         tp->ns = inode->i_sb->s_fs_info;
2256         return 0;
2257 }
2258 
2259 static const struct file_operations proc_timers_operations = {
2260         .open           = proc_timers_open,
2261         .read           = seq_read,
2262         .llseek         = seq_lseek,
2263         .release        = seq_release_private,
2264 };
2265 #endif
2266 
2267 static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2268                                         size_t count, loff_t *offset)
2269 {
2270         struct inode *inode = file_inode(file);
2271         struct task_struct *p;
2272         u64 slack_ns;
2273         int err;
2274 
2275         err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2276         if (err < 0)
2277                 return err;
2278 
2279         p = get_proc_task(inode);
2280         if (!p)
2281                 return -ESRCH;
2282 
2283         if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) {
2284                 task_lock(p);
2285                 if (slack_ns == 0)
2286                         p->timer_slack_ns = p->default_timer_slack_ns;
2287                 else
2288                         p->timer_slack_ns = slack_ns;
2289                 task_unlock(p);
2290         } else
2291                 count = -EPERM;
2292 
2293         put_task_struct(p);
2294 
2295         return count;
2296 }
2297 
2298 static int timerslack_ns_show(struct seq_file *m, void *v)
2299 {
2300         struct inode *inode = m->private;
2301         struct task_struct *p;
2302         int err =  0;
2303 
2304         p = get_proc_task(inode);
2305         if (!p)
2306                 return -ESRCH;
2307 
2308         if (ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)) {
2309                 task_lock(p);
2310                 seq_printf(m, "%llu\n", p->timer_slack_ns);
2311                 task_unlock(p);
2312         } else
2313                 err = -EPERM;
2314 
2315         put_task_struct(p);
2316 
2317         return err;
2318 }
2319 
2320 static int timerslack_ns_open(struct inode *inode, struct file *filp)
2321 {
2322         return single_open(filp, timerslack_ns_show, inode);
2323 }
2324 
2325 static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2326         .open           = timerslack_ns_open,
2327         .read           = seq_read,
2328         .write          = timerslack_ns_write,
2329         .llseek         = seq_lseek,
2330         .release        = single_release,
2331 };
2332 
2333 static int proc_pident_instantiate(struct inode *dir,
2334         struct dentry *dentry, struct task_struct *task, const void *ptr)
2335 {
2336         const struct pid_entry *p = ptr;
2337         struct inode *inode;
2338         struct proc_inode *ei;
2339 
2340         inode = proc_pid_make_inode(dir->i_sb, task);
2341         if (!inode)
2342                 goto out;
2343 
2344         ei = PROC_I(inode);
2345         inode->i_mode = p->mode;
2346         if (S_ISDIR(inode->i_mode))
2347                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2348         if (p->iop)
2349                 inode->i_op = p->iop;
2350         if (p->fop)
2351                 inode->i_fop = p->fop;
2352         ei->op = p->op;
2353         d_set_d_op(dentry, &pid_dentry_operations);
2354         d_add(dentry, inode);
2355         /* Close the race of the process dying before we return the dentry */
2356         if (pid_revalidate(dentry, 0))
2357                 return 0;
2358 out:
2359         return -ENOENT;
2360 }
2361 
2362 static struct dentry *proc_pident_lookup(struct inode *dir, 
2363                                          struct dentry *dentry,
2364                                          const struct pid_entry *ents,
2365                                          unsigned int nents)
2366 {
2367         int error;
2368         struct task_struct *task = get_proc_task(dir);
2369         const struct pid_entry *p, *last;
2370 
2371         error = -ENOENT;
2372 
2373         if (!task)
2374                 goto out_no_task;
2375 
2376         /*
2377          * Yes, it does not scale. And it should not. Don't add
2378          * new entries into /proc/<tgid>/ without very good reasons.
2379          */
2380         last = &ents[nents - 1];
2381         for (p = ents; p <= last; p++) {
2382                 if (p->len != dentry->d_name.len)
2383                         continue;
2384                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2385                         break;
2386         }
2387         if (p > last)
2388                 goto out;
2389 
2390         error = proc_pident_instantiate(dir, dentry, task, p);
2391 out:
2392         put_task_struct(task);
2393 out_no_task:
2394         return ERR_PTR(error);
2395 }
2396 
2397 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2398                 const struct pid_entry *ents, unsigned int nents)
2399 {
2400         struct task_struct *task = get_proc_task(file_inode(file));
2401         const struct pid_entry *p;
2402 
2403         if (!task)
2404                 return -ENOENT;
2405 
2406         if (!dir_emit_dots(file, ctx))
2407                 goto out;
2408 
2409         if (ctx->pos >= nents + 2)
2410                 goto out;
2411 
2412         for (p = ents + (ctx->pos - 2); p <= ents + nents - 1; p++) {
2413                 if (!proc_fill_cache(file, ctx, p->name, p->len,
2414                                 proc_pident_instantiate, task, p))
2415                         break;
2416                 ctx->pos++;
2417         }
2418 out:
2419         put_task_struct(task);
2420         return 0;
2421 }
2422 
2423 #ifdef CONFIG_SECURITY
2424 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2425                                   size_t count, loff_t *ppos)
2426 {
2427         struct inode * inode = file_inode(file);
2428         char *p = NULL;
2429         ssize_t length;
2430         struct task_struct *task = get_proc_task(inode);
2431 
2432         if (!task)
2433                 return -ESRCH;
2434 
2435         length = security_getprocattr(task,
2436                                       (char*)file->f_path.dentry->d_name.name,
2437                                       &p);
2438         put_task_struct(task);
2439         if (length > 0)
2440                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2441         kfree(p);
2442         return length;
2443 }
2444 
2445 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2446                                    size_t count, loff_t *ppos)
2447 {
2448         struct inode * inode = file_inode(file);
2449         void *page;
2450         ssize_t length;
2451         struct task_struct *task = get_proc_task(inode);
2452 
2453         length = -ESRCH;
2454         if (!task)
2455                 goto out_no_task;
2456         if (count > PAGE_SIZE)
2457                 count = PAGE_SIZE;
2458 
2459         /* No partial writes. */
2460         length = -EINVAL;
2461         if (*ppos != 0)
2462                 goto out;
2463 
2464         page = memdup_user(buf, count);
2465         if (IS_ERR(page)) {
2466                 length = PTR_ERR(page);
2467                 goto out;
2468         }
2469 
2470         /* Guard against adverse ptrace interaction */
2471         length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2472         if (length < 0)
2473                 goto out_free;
2474 
2475         length = security_setprocattr(task,
2476                                       (char*)file->f_path.dentry->d_name.name,
2477                                       page, count);
2478         mutex_unlock(&task->signal->cred_guard_mutex);
2479 out_free:
2480         kfree(page);
2481 out:
2482         put_task_struct(task);
2483 out_no_task:
2484         return length;
2485 }
2486 
2487 static const struct file_operations proc_pid_attr_operations = {
2488         .read           = proc_pid_attr_read,
2489         .write          = proc_pid_attr_write,
2490         .llseek         = generic_file_llseek,
2491 };
2492 
2493 static const struct pid_entry attr_dir_stuff[] = {
2494         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2495         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2496         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2497         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2498         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2499         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2500 };
2501 
2502 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2503 {
2504         return proc_pident_readdir(file, ctx, 
2505                                    attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2506 }
2507 
2508 static const struct file_operations proc_attr_dir_operations = {
2509         .read           = generic_read_dir,
2510         .iterate_shared = proc_attr_dir_readdir,
2511         .llseek         = generic_file_llseek,
2512 };
2513 
2514 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2515                                 struct dentry *dentry, unsigned int flags)
2516 {
2517         return proc_pident_lookup(dir, dentry,
2518                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2519 }
2520 
2521 static const struct inode_operations proc_attr_dir_inode_operations = {
2522         .lookup         = proc_attr_dir_lookup,
2523         .getattr        = pid_getattr,
2524         .setattr        = proc_setattr,
2525 };
2526 
2527 #endif
2528 
2529 #ifdef CONFIG_ELF_CORE
2530 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2531                                          size_t count, loff_t *ppos)
2532 {
2533         struct task_struct *task = get_proc_task(file_inode(file));
2534         struct mm_struct *mm;
2535         char buffer[PROC_NUMBUF];
2536         size_t len;
2537         int ret;
2538 
2539         if (!task)
2540                 return -ESRCH;
2541 
2542         ret = 0;
2543         mm = get_task_mm(task);
2544         if (mm) {
2545                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2546                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2547                                 MMF_DUMP_FILTER_SHIFT));
2548                 mmput(mm);
2549                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2550         }
2551 
2552         put_task_struct(task);
2553 
2554         return ret;
2555 }
2556 
2557 static ssize_t proc_coredump_filter_write(struct file *file,
2558                                           const char __user *buf,
2559                                           size_t count,
2560                                           loff_t *ppos)
2561 {
2562         struct task_struct *task;
2563         struct mm_struct *mm;
2564         unsigned int val;
2565         int ret;
2566         int i;
2567         unsigned long mask;
2568 
2569         ret = kstrtouint_from_user(buf, count, 0, &val);
2570         if (ret < 0)
2571                 return ret;
2572 
2573         ret = -ESRCH;
2574         task = get_proc_task(file_inode(file));
2575         if (!task)
2576                 goto out_no_task;
2577 
2578         mm = get_task_mm(task);
2579         if (!mm)
2580                 goto out_no_mm;
2581         ret = 0;
2582 
2583         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2584                 if (val & mask)
2585                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2586                 else
2587                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2588         }
2589 
2590         mmput(mm);
2591  out_no_mm:
2592         put_task_struct(task);
2593  out_no_task:
2594         if (ret < 0)
2595                 return ret;
2596         return count;
2597 }
2598 
2599 static const struct file_operations proc_coredump_filter_operations = {
2600         .read           = proc_coredump_filter_read,
2601         .write          = proc_coredump_filter_write,
2602         .llseek         = generic_file_llseek,
2603 };
2604 #endif
2605 
2606 #ifdef CONFIG_TASK_IO_ACCOUNTING
2607 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2608 {
2609         struct task_io_accounting acct = task->ioac;
2610         unsigned long flags;
2611         int result;
2612 
2613         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2614         if (result)
2615                 return result;
2616 
2617         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2618                 result = -EACCES;
2619                 goto out_unlock;
2620         }
2621 
2622         if (whole && lock_task_sighand(task, &flags)) {
2623                 struct task_struct *t = task;
2624 
2625                 task_io_accounting_add(&acct, &task->signal->ioac);
2626                 while_each_thread(task, t)
2627                         task_io_accounting_add(&acct, &t->ioac);
2628 
2629                 unlock_task_sighand(task, &flags);
2630         }
2631         seq_printf(m,
2632                    "rchar: %llu\n"
2633                    "wchar: %llu\n"
2634                    "syscr: %llu\n"
2635                    "syscw: %llu\n"
2636                    "read_bytes: %llu\n"
2637                    "write_bytes: %llu\n"
2638                    "cancelled_write_bytes: %llu\n",
2639                    (unsigned long long)acct.rchar,
2640                    (unsigned long long)acct.wchar,
2641                    (unsigned long long)acct.syscr,
2642                    (unsigned long long)acct.syscw,
2643                    (unsigned long long)acct.read_bytes,
2644                    (unsigned long long)acct.write_bytes,
2645                    (unsigned long long)acct.cancelled_write_bytes);
2646         result = 0;
2647 
2648 out_unlock:
2649         mutex_unlock(&task->signal->cred_guard_mutex);
2650         return result;
2651 }
2652 
2653 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2654                                   struct pid *pid, struct task_struct *task)
2655 {
2656         return do_io_accounting(task, m, 0);
2657 }
2658 
2659 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2660                                    struct pid *pid, struct task_struct *task)
2661 {
2662         return do_io_accounting(task, m, 1);
2663 }
2664 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2665 
2666 #ifdef CONFIG_USER_NS
2667 static int proc_id_map_open(struct inode *inode, struct file *file,
2668         const struct seq_operations *seq_ops)
2669 {
2670         struct user_namespace *ns = NULL;
2671         struct task_struct *task;
2672         struct seq_file *seq;
2673         int ret = -EINVAL;
2674 
2675         task = get_proc_task(inode);
2676         if (task) {
2677                 rcu_read_lock();
2678                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2679                 rcu_read_unlock();
2680                 put_task_struct(task);
2681         }
2682         if (!ns)
2683                 goto err;
2684 
2685         ret = seq_open(file, seq_ops);
2686         if (ret)
2687                 goto err_put_ns;
2688 
2689         seq = file->private_data;
2690         seq->private = ns;
2691 
2692         return 0;
2693 err_put_ns:
2694         put_user_ns(ns);
2695 err:
2696         return ret;
2697 }
2698 
2699 static int proc_id_map_release(struct inode *inode, struct file *file)
2700 {
2701         struct seq_file *seq = file->private_data;
2702         struct user_namespace *ns = seq->private;
2703         put_user_ns(ns);
2704         return seq_release(inode, file);
2705 }
2706 
2707 static int proc_uid_map_open(struct inode *inode, struct file *file)
2708 {
2709         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2710 }
2711 
2712 static int proc_gid_map_open(struct inode *inode, struct file *file)
2713 {
2714         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2715 }
2716 
2717 static int proc_projid_map_open(struct inode *inode, struct file *file)
2718 {
2719         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2720 }
2721 
2722 static const struct file_operations proc_uid_map_operations = {
2723         .open           = proc_uid_map_open,
2724         .write          = proc_uid_map_write,
2725         .read           = seq_read,
2726         .llseek         = seq_lseek,
2727         .release        = proc_id_map_release,
2728 };
2729 
2730 static const struct file_operations proc_gid_map_operations = {
2731         .open           = proc_gid_map_open,
2732         .write          = proc_gid_map_write,
2733         .read           = seq_read,
2734         .llseek         = seq_lseek,
2735         .release        = proc_id_map_release,
2736 };
2737 
2738 static const struct file_operations proc_projid_map_operations = {
2739         .open           = proc_projid_map_open,
2740         .write          = proc_projid_map_write,
2741         .read           = seq_read,
2742         .llseek         = seq_lseek,
2743         .release        = proc_id_map_release,
2744 };
2745 
2746 static int proc_setgroups_open(struct inode *inode, struct file *file)
2747 {
2748         struct user_namespace *ns = NULL;
2749         struct task_struct *task;
2750         int ret;
2751 
2752         ret = -ESRCH;
2753         task = get_proc_task(inode);
2754         if (task) {
2755                 rcu_read_lock();
2756                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2757                 rcu_read_unlock();
2758                 put_task_struct(task);
2759         }
2760         if (!ns)
2761                 goto err;
2762 
2763         if (file->f_mode & FMODE_WRITE) {
2764                 ret = -EACCES;
2765                 if (!ns_capable(ns, CAP_SYS_ADMIN))
2766                         goto err_put_ns;
2767         }
2768 
2769         ret = single_open(file, &proc_setgroups_show, ns);
2770         if (ret)
2771                 goto err_put_ns;
2772 
2773         return 0;
2774 err_put_ns:
2775         put_user_ns(ns);
2776 err:
2777         return ret;
2778 }
2779 
2780 static int proc_setgroups_release(struct inode *inode, struct file *file)
2781 {
2782         struct seq_file *seq = file->private_data;
2783         struct user_namespace *ns = seq->private;
2784         int ret = single_release(inode, file);
2785         put_user_ns(ns);
2786         return ret;
2787 }
2788 
2789 static const struct file_operations proc_setgroups_operations = {
2790         .open           = proc_setgroups_open,
2791         .write          = proc_setgroups_write,
2792         .read           = seq_read,
2793         .llseek         = seq_lseek,
2794         .release        = proc_setgroups_release,
2795 };
2796 #endif /* CONFIG_USER_NS */
2797 
2798 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2799                                 struct pid *pid, struct task_struct *task)
2800 {
2801         int err = lock_trace(task);
2802         if (!err) {
2803                 seq_printf(m, "%08x\n", task->personality);
2804                 unlock_trace(task);
2805         }
2806         return err;
2807 }
2808 
2809 /*
2810  * Thread groups
2811  */
2812 static const struct file_operations proc_task_operations;
2813 static const struct inode_operations proc_task_inode_operations;
2814 
2815 static const struct pid_entry tgid_base_stuff[] = {
2816         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2817         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2818         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2819         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2820         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2821 #ifdef CONFIG_NET
2822         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2823 #endif
2824         REG("environ",    S_IRUSR, proc_environ_operations),
2825         ONE("auxv",       S_IRUSR, proc_pid_auxv),
2826         ONE("status",     S_IRUGO, proc_pid_status),
2827         ONE("personality", S_IRUSR, proc_pid_personality),
2828         ONE("limits",     S_IRUGO, proc_pid_limits),
2829 #ifdef CONFIG_SCHED_DEBUG
2830         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2831 #endif
2832 #ifdef CONFIG_SCHED_AUTOGROUP
2833         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2834 #endif
2835         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2836 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2837         ONE("syscall",    S_IRUSR, proc_pid_syscall),
2838 #endif
2839         REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
2840         ONE("stat",       S_IRUGO, proc_tgid_stat),
2841         ONE("statm",      S_IRUGO, proc_pid_statm),
2842         REG("maps",       S_IRUGO, proc_pid_maps_operations),
2843 #ifdef CONFIG_NUMA
2844         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2845 #endif
2846         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2847         LNK("cwd",        proc_cwd_link),
2848         LNK("root",       proc_root_link),
2849         LNK("exe",        proc_exe_link),
2850         REG("mounts",     S_IRUGO, proc_mounts_operations),
2851         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2852         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2853 #ifdef CONFIG_PROC_PAGE_MONITOR
2854         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2855         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2856         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
2857 #endif
2858 #ifdef CONFIG_SECURITY
2859         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2860 #endif
2861 #ifdef CONFIG_KALLSYMS
2862         ONE("wchan",      S_IRUGO, proc_pid_wchan),
2863 #endif
2864 #ifdef CONFIG_STACKTRACE
2865         ONE("stack",      S_IRUSR, proc_pid_stack),
2866 #endif
2867 #ifdef CONFIG_SCHED_INFO
2868         ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
2869 #endif
2870 #ifdef CONFIG_LATENCYTOP
2871         REG("latency",  S_IRUGO, proc_lstats_operations),
2872 #endif
2873 #ifdef CONFIG_PROC_PID_CPUSET
2874         ONE("cpuset",     S_IRUGO, proc_cpuset_show),
2875 #endif
2876 #ifdef CONFIG_CGROUPS
2877         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
2878 #endif
2879         ONE("oom_score",  S_IRUGO, proc_oom_score),
2880         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
2881         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2882 #ifdef CONFIG_AUDITSYSCALL
2883         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2884         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2885 #endif
2886 #ifdef CONFIG_FAULT_INJECTION
2887         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2888 #endif
2889 #ifdef CONFIG_ELF_CORE
2890         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2891 #endif
2892 #ifdef CONFIG_TASK_IO_ACCOUNTING
2893         ONE("io",       S_IRUSR, proc_tgid_io_accounting),
2894 #endif
2895 #ifdef CONFIG_HARDWALL
2896         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
2897 #endif
2898 #ifdef CONFIG_USER_NS
2899         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
2900         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
2901         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
2902         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
2903 #endif
2904 #ifdef CONFIG_CHECKPOINT_RESTORE
2905         REG("timers",     S_IRUGO, proc_timers_operations),
2906 #endif
2907         REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
2908 };
2909 
2910 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
2911 {
2912         return proc_pident_readdir(file, ctx,
2913                                    tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2914 }
2915 
2916 static const struct file_operations proc_tgid_base_operations = {
2917         .read           = generic_read_dir,
2918         .iterate_shared = proc_tgid_base_readdir,
2919         .llseek         = generic_file_llseek,
2920 };
2921 
2922 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
2923 {
2924         return proc_pident_lookup(dir, dentry,
2925                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2926 }
2927 
2928 static const struct inode_operations proc_tgid_base_inode_operations = {
2929         .lookup         = proc_tgid_base_lookup,
2930         .getattr        = pid_getattr,
2931         .setattr        = proc_setattr,
2932         .permission     = proc_pid_permission,
2933 };
2934 
2935 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2936 {
2937         struct dentry *dentry, *leader, *dir;
2938         char buf[PROC_NUMBUF];
2939         struct qstr name;
2940 
2941         name.name = buf;
2942         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2943         /* no ->d_hash() rejects on procfs */
2944         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2945         if (dentry) {
2946                 d_invalidate(dentry);
2947                 dput(dentry);
2948         }
2949 
2950         if (pid == tgid)
2951                 return;
2952 
2953         name.name = buf;
2954         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2955         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2956         if (!leader)
2957                 goto out;
2958 
2959         name.name = "task";
2960         name.len = strlen(name.name);
2961         dir = d_hash_and_lookup(leader, &name);
2962         if (!dir)
2963                 goto out_put_leader;
2964 
2965         name.name = buf;
2966         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2967         dentry = d_hash_and_lookup(dir, &name);
2968         if (dentry) {
2969                 d_invalidate(dentry);
2970                 dput(dentry);
2971         }
2972 
2973         dput(dir);
2974 out_put_leader:
2975         dput(leader);
2976 out:
2977         return;
2978 }
2979 
2980 /**
2981  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2982  * @task: task that should be flushed.
2983  *
2984  * When flushing dentries from proc, one needs to flush them from global
2985  * proc (proc_mnt) and from all the namespaces' procs this task was seen
2986  * in. This call is supposed to do all of this job.
2987  *
2988  * Looks in the dcache for
2989  * /proc/@pid
2990  * /proc/@tgid/task/@pid
2991  * if either directory is present flushes it and all of it'ts children
2992  * from the dcache.
2993  *
2994  * It is safe and reasonable to cache /proc entries for a task until
2995  * that task exits.  After that they just clog up the dcache with
2996  * useless entries, possibly causing useful dcache entries to be
2997  * flushed instead.  This routine is proved to flush those useless
2998  * dcache entries at process exit time.
2999  *
3000  * NOTE: This routine is just an optimization so it does not guarantee
3001  *       that no dcache entries will exist at process exit time it
3002  *       just makes it very unlikely that any will persist.
3003  */
3004 
3005 void proc_flush_task(struct task_struct *task)
3006 {
3007         int i;
3008         struct pid *pid, *tgid;
3009         struct upid *upid;
3010 
3011         pid = task_pid(task);
3012         tgid = task_tgid(task);
3013 
3014         for (i = 0; i <= pid->level; i++) {
3015                 upid = &pid->numbers[i];
3016                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3017                                         tgid->numbers[i].nr);
3018         }
3019 }
3020 
3021 static int proc_pid_instantiate(struct inode *dir,
3022                                    struct dentry * dentry,
3023                                    struct task_struct *task, const void *ptr)
3024 {
3025         struct inode *inode;
3026 
3027         inode = proc_pid_make_inode(dir->i_sb, task);
3028         if (!inode)
3029                 goto out;
3030 
3031         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3032         inode->i_op = &proc_tgid_base_inode_operations;
3033         inode->i_fop = &proc_tgid_base_operations;
3034         inode->i_flags|=S_IMMUTABLE;
3035 
3036         set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
3037                                                   ARRAY_SIZE(tgid_base_stuff)));
3038 
3039         d_set_d_op(dentry, &pid_dentry_operations);
3040 
3041         d_add(dentry, inode);
3042         /* Close the race of the process dying before we return the dentry */
3043         if (pid_revalidate(dentry, 0))
3044                 return 0;
3045 out:
3046         return -ENOENT;
3047 }
3048 
3049 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3050 {
3051         int result = -ENOENT;
3052         struct task_struct *task;
3053         unsigned tgid;
3054         struct pid_namespace *ns;
3055 
3056         tgid = name_to_int(&dentry->d_name);
3057         if (tgid == ~0U)
3058                 goto out;
3059 
3060         ns = dentry->d_sb->s_fs_info;
3061         rcu_read_lock();
3062         task = find_task_by_pid_ns(tgid, ns);
3063         if (task)
3064                 get_task_struct(task);
3065         rcu_read_unlock();
3066         if (!task)
3067                 goto out;
3068 
3069         result = proc_pid_instantiate(dir, dentry, task, NULL);
3070         put_task_struct(task);
3071 out:
3072         return ERR_PTR(result);
3073 }
3074 
3075 /*
3076  * Find the first task with tgid >= tgid
3077  *
3078  */
3079 struct tgid_iter {
3080         unsigned int tgid;
3081         struct task_struct *task;
3082 };
3083 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3084 {
3085         struct pid *pid;
3086 
3087         if (iter.task)
3088                 put_task_struct(iter.task);
3089         rcu_read_lock();
3090 retry:
3091         iter.task = NULL;
3092         pid = find_ge_pid(iter.tgid, ns);
3093         if (pid) {
3094                 iter.tgid = pid_nr_ns(pid, ns);
3095                 iter.task = pid_task(pid, PIDTYPE_PID);
3096                 /* What we to know is if the pid we have find is the
3097                  * pid of a thread_group_leader.  Testing for task
3098                  * being a thread_group_leader is the obvious thing
3099                  * todo but there is a window when it fails, due to
3100                  * the pid transfer logic in de_thread.
3101                  *
3102                  * So we perform the straight forward test of seeing
3103                  * if the pid we have found is the pid of a thread
3104                  * group leader, and don't worry if the task we have
3105                  * found doesn't happen to be a thread group leader.
3106                  * As we don't care in the case of readdir.
3107                  */
3108                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3109                         iter.tgid += 1;
3110                         goto retry;
3111                 }
3112                 get_task_struct(iter.task);
3113         }
3114         rcu_read_unlock();
3115         return iter;
3116 }
3117 
3118 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3119 
3120 /* for the /proc/ directory itself, after non-process stuff has been done */
3121 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3122 {
3123         struct tgid_iter iter;
3124         struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info;
3125         loff_t pos = ctx->pos;
3126 
3127         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3128                 return 0;
3129 
3130         if (pos == TGID_OFFSET - 2) {
3131                 struct inode *inode = d_inode(ns->proc_self);
3132                 if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3133                         return 0;
3134                 ctx->pos = pos = pos + 1;
3135         }
3136         if (pos == TGID_OFFSET - 1) {
3137                 struct inode *inode = d_inode(ns->proc_thread_self);
3138                 if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3139                         return 0;
3140                 ctx->pos = pos = pos + 1;
3141         }
3142         iter.tgid = pos - TGID_OFFSET;
3143         iter.task = NULL;
3144         for (iter = next_tgid(ns, iter);
3145              iter.task;
3146              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3147                 char name[PROC_NUMBUF];
3148                 int len;
3149                 if (!has_pid_permissions(ns, iter.task, 2))
3150                         continue;
3151 
3152                 len = snprintf(name, sizeof(name), "%d", iter.tgid);
3153                 ctx->pos = iter.tgid + TGID_OFFSET;
3154                 if (!proc_fill_cache(file, ctx, name, len,
3155                                      proc_pid_instantiate, iter.task, NULL)) {
3156                         put_task_struct(iter.task);
3157                         return 0;
3158                 }
3159         }
3160         ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3161         return 0;
3162 }
3163 
3164 /*
3165  * proc_tid_comm_permission is a special permission function exclusively
3166  * used for the node /proc/<pid>/task/<tid>/comm.
3167  * It bypasses generic permission checks in the case where a task of the same
3168  * task group attempts to access the node.
3169  * The rationale behind this is that glibc and bionic access this node for
3170  * cross thread naming (pthread_set/getname_np(!self)). However, if
3171  * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3172  * which locks out the cross thread naming implementation.
3173  * This function makes sure that the node is always accessible for members of
3174  * same thread group.
3175  */
3176 static int proc_tid_comm_permission(struct inode *inode, int mask)
3177 {
3178         bool is_same_tgroup;
3179         struct task_struct *task;
3180 
3181         task = get_proc_task(inode);
3182         if (!task)
3183                 return -ESRCH;
3184         is_same_tgroup = same_thread_group(current, task);
3185         put_task_struct(task);
3186 
3187         if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3188                 /* This file (/proc/<pid>/task/<tid>/comm) can always be
3189                  * read or written by the members of the corresponding
3190                  * thread group.
3191                  */
3192                 return 0;
3193         }
3194 
3195         return generic_permission(inode, mask);
3196 }
3197 
3198 static const struct inode_operations proc_tid_comm_inode_operations = {
3199                 .permission = proc_tid_comm_permission,
3200 };
3201 
3202 /*
3203  * Tasks
3204  */
3205 static const struct pid_entry tid_base_stuff[] = {
3206         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3207         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3208         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3209 #ifdef CONFIG_NET
3210         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3211 #endif
3212         REG("environ",   S_IRUSR, proc_environ_operations),
3213         ONE("auxv",      S_IRUSR, proc_pid_auxv),
3214         ONE("status",    S_IRUGO, proc_pid_status),
3215         ONE("personality", S_IRUSR, proc_pid_personality),
3216         ONE("limits",    S_IRUGO, proc_pid_limits),
3217 #ifdef CONFIG_SCHED_DEBUG
3218         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3219 #endif
3220         NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3221                          &proc_tid_comm_inode_operations,
3222                          &proc_pid_set_comm_operations, {}),
3223 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3224         ONE("syscall",   S_IRUSR, proc_pid_syscall),
3225 #endif
3226         REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3227         ONE("stat",      S_IRUGO, proc_tid_stat),
3228         ONE("statm",     S_IRUGO, proc_pid_statm),
3229         REG("maps",      S_IRUGO, proc_tid_maps_operations),
3230 #ifdef CONFIG_PROC_CHILDREN
3231         REG("children",  S_IRUGO, proc_tid_children_operations),
3232 #endif
3233 #ifdef CONFIG_NUMA
3234         REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3235 #endif
3236         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3237         LNK("cwd",       proc_cwd_link),
3238         LNK("root",      proc_root_link),
3239         LNK("exe",       proc_exe_link),
3240         REG("mounts",    S_IRUGO, proc_mounts_operations),
3241         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3242 #ifdef CONFIG_PROC_PAGE_MONITOR
3243         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3244         REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3245         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3246 #endif
3247 #ifdef CONFIG_SECURITY
3248         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3249 #endif
3250 #ifdef CONFIG_KALLSYMS
3251         ONE("wchan",     S_IRUGO, proc_pid_wchan),
3252 #endif
3253 #ifdef CONFIG_STACKTRACE
3254         ONE("stack",      S_IRUSR, proc_pid_stack),
3255 #endif
3256 #ifdef CONFIG_SCHED_INFO
3257         ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3258 #endif
3259 #ifdef CONFIG_LATENCYTOP
3260         REG("latency",  S_IRUGO, proc_lstats_operations),
3261 #endif
3262 #ifdef CONFIG_PROC_PID_CPUSET
3263         ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3264 #endif
3265 #ifdef CONFIG_CGROUPS
3266         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3267 #endif
3268         ONE("oom_score", S_IRUGO, proc_oom_score),
3269         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3270         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3271 #ifdef CONFIG_AUDITSYSCALL
3272         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3273         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3274 #endif
3275 #ifdef CONFIG_FAULT_INJECTION
3276         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3277 #endif
3278 #ifdef CONFIG_TASK_IO_ACCOUNTING
3279         ONE("io",       S_IRUSR, proc_tid_io_accounting),
3280 #endif
3281 #ifdef CONFIG_HARDWALL
3282         ONE("hardwall",   S_IRUGO, proc_pid_hardwall),
3283 #endif
3284 #ifdef CONFIG_USER_NS
3285         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3286         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3287         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3288         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3289 #endif
3290 };
3291 
3292 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3293 {
3294         return proc_pident_readdir(file, ctx,
3295                                    tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3296 }
3297 
3298 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3299 {
3300         return proc_pident_lookup(dir, dentry,
3301                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3302 }
3303 
3304 static const struct file_operations proc_tid_base_operations = {
3305         .read           = generic_read_dir,
3306         .iterate_shared = proc_tid_base_readdir,
3307         .llseek         = generic_file_llseek,
3308 };
3309 
3310 static const struct inode_operations proc_tid_base_inode_operations = {
3311         .lookup         = proc_tid_base_lookup,
3312         .getattr        = pid_getattr,
3313         .setattr        = proc_setattr,
3314 };
3315 
3316 static int proc_task_instantiate(struct inode *dir,
3317         struct dentry *dentry, struct task_struct *task, const void *ptr)
3318 {
3319         struct inode *inode;
3320         inode = proc_pid_make_inode(dir->i_sb, task);
3321 
3322         if (!inode)
3323                 goto out;
3324         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3325         inode->i_op = &proc_tid_base_inode_operations;
3326         inode->i_fop = &proc_tid_base_operations;
3327         inode->i_flags|=S_IMMUTABLE;
3328 
3329         set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
3330                                                   ARRAY_SIZE(tid_base_stuff)));
3331 
3332         d_set_d_op(dentry, &pid_dentry_operations);
3333 
3334         d_add(dentry, inode);
3335         /* Close the race of the process dying before we return the dentry */
3336         if (pid_revalidate(dentry, 0))
3337                 return 0;
3338 out:
3339         return -ENOENT;
3340 }
3341 
3342 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3343 {
3344         int result = -ENOENT;
3345         struct task_struct *task;
3346         struct task_struct *leader = get_proc_task(dir);
3347         unsigned tid;
3348         struct pid_namespace *ns;
3349 
3350         if (!leader)
3351                 goto out_no_task;
3352 
3353         tid = name_to_int(&dentry->d_name);
3354         if (tid == ~0U)
3355                 goto out;
3356 
3357         ns = dentry->d_sb->s_fs_info;
3358         rcu_read_lock();
3359         task = find_task_by_pid_ns(tid, ns);
3360         if (task)
3361                 get_task_struct(task);
3362         rcu_read_unlock();
3363         if (!task)
3364                 goto out;
3365         if (!same_thread_group(leader, task))
3366                 goto out_drop_task;
3367 
3368         result = proc_task_instantiate(dir, dentry, task, NULL);
3369 out_drop_task:
3370         put_task_struct(task);
3371 out:
3372         put_task_struct(leader);
3373 out_no_task:
3374         return ERR_PTR(result);
3375 }
3376 
3377 /*
3378  * Find the first tid of a thread group to return to user space.
3379  *
3380  * Usually this is just the thread group leader, but if the users
3381  * buffer was too small or there was a seek into the middle of the
3382  * directory we have more work todo.
3383  *
3384  * In the case of a short read we start with find_task_by_pid.
3385  *
3386  * In the case of a seek we start with the leader and walk nr
3387  * threads past it.
3388  */
3389 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3390                                         struct pid_namespace *ns)
3391 {
3392         struct task_struct *pos, *task;
3393         unsigned long nr = f_pos;
3394 
3395         if (nr != f_pos)        /* 32bit overflow? */
3396                 return NULL;
3397 
3398         rcu_read_lock();
3399         task = pid_task(pid, PIDTYPE_PID);
3400         if (!task)
3401                 goto fail;
3402 
3403         /* Attempt to start with the tid of a thread */
3404         if (tid && nr) {
3405                 pos = find_task_by_pid_ns(tid, ns);
3406                 if (pos && same_thread_group(pos, task))
3407                         goto found;
3408         }
3409 
3410         /* If nr exceeds the number of threads there is nothing todo */
3411         if (nr >= get_nr_threads(task))
3412                 goto fail;
3413 
3414         /* If we haven't found our starting place yet start
3415          * with the leader and walk nr threads forward.
3416          */
3417         pos = task = task->group_leader;
3418         do {
3419                 if (!nr--)
3420                         goto found;
3421         } while_each_thread(task, pos);
3422 fail:
3423         pos = NULL;
3424         goto out;
3425 found:
3426         get_task_struct(pos);
3427 out:
3428         rcu_read_unlock();
3429         return pos;
3430 }
3431 
3432 /*
3433  * Find the next thread in the thread list.
3434  * Return NULL if there is an error or no next thread.
3435  *
3436  * The reference to the input task_struct is released.
3437  */
3438 static struct task_struct *next_tid(struct task_struct *start)
3439 {
3440         struct task_struct *pos = NULL;
3441         rcu_read_lock();
3442         if (pid_alive(start)) {
3443                 pos = next_thread(start);
3444                 if (thread_group_leader(pos))
3445                         pos = NULL;
3446                 else
3447                         get_task_struct(pos);
3448         }
3449         rcu_read_unlock();
3450         put_task_struct(start);
3451         return pos;
3452 }
3453 
3454 /* for the /proc/TGID/task/ directories */
3455 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3456 {
3457         struct inode *inode = file_inode(file);
3458         struct task_struct *task;
3459         struct pid_namespace *ns;
3460         int tid;
3461 
3462         if (proc_inode_is_dead(inode))
3463                 return -ENOENT;
3464 
3465         if (!dir_emit_dots(file, ctx))
3466                 return 0;
3467 
3468         /* f_version caches the tgid value that the last readdir call couldn't
3469          * return. lseek aka telldir automagically resets f_version to 0.
3470          */
3471         ns = inode->i_sb->s_fs_info;
3472         tid = (int)file->f_version;
3473         file->f_version = 0;
3474         for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3475              task;
3476              task = next_tid(task), ctx->pos++) {
3477                 char name[PROC_NUMBUF];
3478                 int len;
3479                 tid = task_pid_nr_ns(task, ns);
3480                 len = snprintf(name, sizeof(name), "%d", tid);
3481                 if (!proc_fill_cache(file, ctx, name, len,
3482                                 proc_task_instantiate, task, NULL)) {
3483                         /* returning this tgid failed, save it as the first
3484                          * pid for the next readir call */
3485                         file->f_version = (u64)tid;
3486                         put_task_struct(task);
3487                         break;
3488                 }
3489         }
3490 
3491         return 0;
3492 }
3493 
3494 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3495 {
3496         struct inode *inode = d_inode(dentry);
3497         struct task_struct *p = get_proc_task(inode);
3498         generic_fillattr(inode, stat);
3499 
3500         if (p) {
3501                 stat->nlink += get_nr_threads(p);
3502                 put_task_struct(p);
3503         }
3504 
3505         return 0;
3506 }
3507 
3508 static const struct inode_operations proc_task_inode_operations = {
3509         .lookup         = proc_task_lookup,
3510         .getattr        = proc_task_getattr,
3511         .setattr        = proc_setattr,
3512         .permission     = proc_pid_permission,
3513 };
3514 
3515 static const struct file_operations proc_task_operations = {
3516         .read           = generic_read_dir,
3517         .iterate_shared = proc_task_readdir,
3518         .llseek         = generic_file_llseek,
3519 };
3520 

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