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

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