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

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  *  linux/fs/proc/base.c
  4  *
  5  *  Copyright (C) 1991, 1992 Linus Torvalds
  6  *
  7  *  proc base directory handling functions
  8  *
  9  *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
 10  *  Instead of using magical inumbers to determine the kind of object
 11  *  we allocate and fill in-core inodes upon lookup. They don't even
 12  *  go into icache. We cache the reference to task_struct upon lookup too.
 13  *  Eventually it should become a filesystem in its own. We don't use the
 14  *  rest of procfs anymore.
 15  *
 16  *
 17  *  Changelog:
 18  *  17-Jan-2005
 19  *  Allan Bezerra
 20  *  Bruna Moreira <bruna.moreira@indt.org.br>
 21  *  Edjard Mota <edjard.mota@indt.org.br>
 22  *  Ilias Biris <ilias.biris@indt.org.br>
 23  *  Mauricio Lin <mauricio.lin@indt.org.br>
 24  *
 25  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
 26  *
 27  *  A new process specific entry (smaps) included in /proc. It shows the
 28  *  size of rss for each memory area. The maps entry lacks information
 29  *  about physical memory size (rss) for each mapped file, i.e.,
 30  *  rss information for executables and library files.
 31  *  This additional information is useful for any tools that need to know
 32  *  about physical memory consumption for a process specific library.
 33  *
 34  *  Changelog:
 35  *  21-Feb-2005
 36  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
 37  *  Pud inclusion in the page table walking.
 38  *
 39  *  ChangeLog:
 40  *  10-Mar-2005
 41  *  10LE Instituto Nokia de Tecnologia - INdT:
 42  *  A better way to walks through the page table as suggested by Hugh Dickins.
 43  *
 44  *  Simo Piiroinen <simo.piiroinen@nokia.com>:
 45  *  Smaps information related to shared, private, clean and dirty pages.
 46  *
 47  *  Paul Mundt <paul.mundt@nokia.com>:
 48  *  Overall revision about smaps.
 49  */
 50 
 51 #include <linux/uaccess.h>
 52 
 53 #include <linux/errno.h>
 54 #include <linux/time.h>
 55 #include <linux/proc_fs.h>
 56 #include <linux/stat.h>
 57 #include <linux/task_io_accounting_ops.h>
 58 #include <linux/init.h>
 59 #include <linux/capability.h>
 60 #include <linux/file.h>
 61 #include <linux/fdtable.h>
 62 #include <linux/generic-radix-tree.h>
 63 #include <linux/string.h>
 64 #include <linux/seq_file.h>
 65 #include <linux/namei.h>
 66 #include <linux/mnt_namespace.h>
 67 #include <linux/mm.h>
 68 #include <linux/swap.h>
 69 #include <linux/rcupdate.h>
 70 #include <linux/kallsyms.h>
 71 #include <linux/stacktrace.h>
 72 #include <linux/resource.h>
 73 #include <linux/module.h>
 74 #include <linux/mount.h>
 75 #include <linux/security.h>
 76 #include <linux/ptrace.h>
 77 #include <linux/tracehook.h>
 78 #include <linux/printk.h>
 79 #include <linux/cache.h>
 80 #include <linux/cgroup.h>
 81 #include <linux/cpuset.h>
 82 #include <linux/audit.h>
 83 #include <linux/poll.h>
 84 #include <linux/nsproxy.h>
 85 #include <linux/oom.h>
 86 #include <linux/elf.h>
 87 #include <linux/pid_namespace.h>
 88 #include <linux/user_namespace.h>
 89 #include <linux/fs_struct.h>
 90 #include <linux/slab.h>
 91 #include <linux/sched/autogroup.h>
 92 #include <linux/sched/mm.h>
 93 #include <linux/sched/coredump.h>
 94 #include <linux/sched/debug.h>
 95 #include <linux/sched/stat.h>
 96 #include <linux/posix-timers.h>
 97 #include <linux/time_namespace.h>
 98 #include <linux/resctrl.h>
 99 #include <trace/events/oom.h>
100 #include "internal.h"
101 #include "fd.h"
102 
103 #include "../../lib/kstrtox.h"
104 
105 /* NOTE:
106  *      Implementing inode permission operations in /proc is almost
107  *      certainly an error.  Permission checks need to happen during
108  *      each system call not at open time.  The reason is that most of
109  *      what we wish to check for permissions in /proc varies at runtime.
110  *
111  *      The classic example of a problem is opening file descriptors
112  *      in /proc for a task before it execs a suid executable.
113  */
114 
115 static u8 nlink_tid __ro_after_init;
116 static u8 nlink_tgid __ro_after_init;
117 
118 struct pid_entry {
119         const char *name;
120         unsigned int len;
121         umode_t mode;
122         const struct inode_operations *iop;
123         const struct file_operations *fop;
124         union proc_op op;
125 };
126 
127 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
128         .name = (NAME),                                 \
129         .len  = sizeof(NAME) - 1,                       \
130         .mode = MODE,                                   \
131         .iop  = IOP,                                    \
132         .fop  = FOP,                                    \
133         .op   = OP,                                     \
134 }
135 
136 #define DIR(NAME, MODE, iops, fops)     \
137         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
138 #define LNK(NAME, get_link)                                     \
139         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
140                 &proc_pid_link_inode_operations, NULL,          \
141                 { .proc_get_link = get_link } )
142 #define REG(NAME, MODE, fops)                           \
143         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
144 #define ONE(NAME, MODE, show)                           \
145         NOD(NAME, (S_IFREG|(MODE)),                     \
146                 NULL, &proc_single_file_operations,     \
147                 { .proc_show = show } )
148 #define ATTR(LSM, NAME, MODE)                           \
149         NOD(NAME, (S_IFREG|(MODE)),                     \
150                 NULL, &proc_pid_attr_operations,        \
151                 { .lsm = LSM })
152 
153 /*
154  * Count the number of hardlinks for the pid_entry table, excluding the .
155  * and .. links.
156  */
157 static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
158         unsigned int n)
159 {
160         unsigned int i;
161         unsigned int count;
162 
163         count = 2;
164         for (i = 0; i < n; ++i) {
165                 if (S_ISDIR(entries[i].mode))
166                         ++count;
167         }
168 
169         return count;
170 }
171 
172 static int get_task_root(struct task_struct *task, struct path *root)
173 {
174         int result = -ENOENT;
175 
176         task_lock(task);
177         if (task->fs) {
178                 get_fs_root(task->fs, root);
179                 result = 0;
180         }
181         task_unlock(task);
182         return result;
183 }
184 
185 static int proc_cwd_link(struct dentry *dentry, struct path *path)
186 {
187         struct task_struct *task = get_proc_task(d_inode(dentry));
188         int result = -ENOENT;
189 
190         if (task) {
191                 task_lock(task);
192                 if (task->fs) {
193                         get_fs_pwd(task->fs, path);
194                         result = 0;
195                 }
196                 task_unlock(task);
197                 put_task_struct(task);
198         }
199         return result;
200 }
201 
202 static int proc_root_link(struct dentry *dentry, struct path *path)
203 {
204         struct task_struct *task = get_proc_task(d_inode(dentry));
205         int result = -ENOENT;
206 
207         if (task) {
208                 result = get_task_root(task, path);
209                 put_task_struct(task);
210         }
211         return result;
212 }
213 
214 /*
215  * If the user used setproctitle(), we just get the string from
216  * user space at arg_start, and limit it to a maximum of one page.
217  */
218 static ssize_t get_mm_proctitle(struct mm_struct *mm, char __user *buf,
219                                 size_t count, unsigned long pos,
220                                 unsigned long arg_start)
221 {
222         char *page;
223         int ret, got;
224 
225         if (pos >= PAGE_SIZE)
226                 return 0;
227 
228         page = (char *)__get_free_page(GFP_KERNEL);
229         if (!page)
230                 return -ENOMEM;
231 
232         ret = 0;
233         got = access_remote_vm(mm, arg_start, page, PAGE_SIZE, FOLL_ANON);
234         if (got > 0) {
235                 int len = strnlen(page, got);
236 
237                 /* Include the NUL character if it was found */
238                 if (len < got)
239                         len++;
240 
241                 if (len > pos) {
242                         len -= pos;
243                         if (len > count)
244                                 len = count;
245                         len -= copy_to_user(buf, page+pos, len);
246                         if (!len)
247                                 len = -EFAULT;
248                         ret = len;
249                 }
250         }
251         free_page((unsigned long)page);
252         return ret;
253 }
254 
255 static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
256                               size_t count, loff_t *ppos)
257 {
258         unsigned long arg_start, arg_end, env_start, env_end;
259         unsigned long pos, len;
260         char *page, c;
261 
262         /* Check if process spawned far enough to have cmdline. */
263         if (!mm->env_end)
264                 return 0;
265 
266         spin_lock(&mm->arg_lock);
267         arg_start = mm->arg_start;
268         arg_end = mm->arg_end;
269         env_start = mm->env_start;
270         env_end = mm->env_end;
271         spin_unlock(&mm->arg_lock);
272 
273         if (arg_start >= arg_end)
274                 return 0;
275 
276         /*
277          * We allow setproctitle() to overwrite the argument
278          * strings, and overflow past the original end. But
279          * only when it overflows into the environment area.
280          */
281         if (env_start != arg_end || env_end < env_start)
282                 env_start = env_end = arg_end;
283         len = env_end - arg_start;
284 
285         /* We're not going to care if "*ppos" has high bits set */
286         pos = *ppos;
287         if (pos >= len)
288                 return 0;
289         if (count > len - pos)
290                 count = len - pos;
291         if (!count)
292                 return 0;
293 
294         /*
295          * Magical special case: if the argv[] end byte is not
296          * zero, the user has overwritten it with setproctitle(3).
297          *
298          * Possible future enhancement: do this only once when
299          * pos is 0, and set a flag in the 'struct file'.
300          */
301         if (access_remote_vm(mm, arg_end-1, &c, 1, FOLL_ANON) == 1 && c)
302                 return get_mm_proctitle(mm, buf, count, pos, arg_start);
303 
304         /*
305          * For the non-setproctitle() case we limit things strictly
306          * to the [arg_start, arg_end[ range.
307          */
308         pos += arg_start;
309         if (pos < arg_start || pos >= arg_end)
310                 return 0;
311         if (count > arg_end - pos)
312                 count = arg_end - pos;
313 
314         page = (char *)__get_free_page(GFP_KERNEL);
315         if (!page)
316                 return -ENOMEM;
317 
318         len = 0;
319         while (count) {
320                 int got;
321                 size_t size = min_t(size_t, PAGE_SIZE, count);
322 
323                 got = access_remote_vm(mm, pos, page, size, FOLL_ANON);
324                 if (got <= 0)
325                         break;
326                 got -= copy_to_user(buf, page, got);
327                 if (unlikely(!got)) {
328                         if (!len)
329                                 len = -EFAULT;
330                         break;
331                 }
332                 pos += got;
333                 buf += got;
334                 len += got;
335                 count -= got;
336         }
337 
338         free_page((unsigned long)page);
339         return len;
340 }
341 
342 static ssize_t get_task_cmdline(struct task_struct *tsk, char __user *buf,
343                                 size_t count, loff_t *pos)
344 {
345         struct mm_struct *mm;
346         ssize_t ret;
347 
348         mm = get_task_mm(tsk);
349         if (!mm)
350                 return 0;
351 
352         ret = get_mm_cmdline(mm, buf, count, pos);
353         mmput(mm);
354         return ret;
355 }
356 
357 static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
358                                      size_t count, loff_t *pos)
359 {
360         struct task_struct *tsk;
361         ssize_t ret;
362 
363         BUG_ON(*pos < 0);
364 
365         tsk = get_proc_task(file_inode(file));
366         if (!tsk)
367                 return -ESRCH;
368         ret = get_task_cmdline(tsk, buf, count, pos);
369         put_task_struct(tsk);
370         if (ret > 0)
371                 *pos += ret;
372         return ret;
373 }
374 
375 static const struct file_operations proc_pid_cmdline_ops = {
376         .read   = proc_pid_cmdline_read,
377         .llseek = generic_file_llseek,
378 };
379 
380 #ifdef CONFIG_KALLSYMS
381 /*
382  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
383  * Returns the resolved symbol.  If that fails, simply return the address.
384  */
385 static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
386                           struct pid *pid, struct task_struct *task)
387 {
388         unsigned long wchan;
389         char symname[KSYM_NAME_LEN];
390 
391         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
392                 goto print0;
393 
394         wchan = get_wchan(task);
395         if (wchan && !lookup_symbol_name(wchan, symname)) {
396                 seq_puts(m, symname);
397                 return 0;
398         }
399 
400 print0:
401         seq_putc(m, '');
402         return 0;
403 }
404 #endif /* CONFIG_KALLSYMS */
405 
406 static int lock_trace(struct task_struct *task)
407 {
408         int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
409         if (err)
410                 return err;
411         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
412                 mutex_unlock(&task->signal->cred_guard_mutex);
413                 return -EPERM;
414         }
415         return 0;
416 }
417 
418 static void unlock_trace(struct task_struct *task)
419 {
420         mutex_unlock(&task->signal->cred_guard_mutex);
421 }
422 
423 #ifdef CONFIG_STACKTRACE
424 
425 #define MAX_STACK_TRACE_DEPTH   64
426 
427 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
428                           struct pid *pid, struct task_struct *task)
429 {
430         unsigned long *entries;
431         int err;
432 
433         /*
434          * The ability to racily run the kernel stack unwinder on a running task
435          * and then observe the unwinder output is scary; while it is useful for
436          * debugging kernel issues, it can also allow an attacker to leak kernel
437          * stack contents.
438          * Doing this in a manner that is at least safe from races would require
439          * some work to ensure that the remote task can not be scheduled; and
440          * even then, this would still expose the unwinder as local attack
441          * surface.
442          * Therefore, this interface is restricted to root.
443          */
444         if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
445                 return -EACCES;
446 
447         entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
448                                 GFP_KERNEL);
449         if (!entries)
450                 return -ENOMEM;
451 
452         err = lock_trace(task);
453         if (!err) {
454                 unsigned int i, nr_entries;
455 
456                 nr_entries = stack_trace_save_tsk(task, entries,
457                                                   MAX_STACK_TRACE_DEPTH, 0);
458 
459                 for (i = 0; i < nr_entries; i++) {
460                         seq_printf(m, "[<0>] %pB\n", (void *)entries[i]);
461                 }
462 
463                 unlock_trace(task);
464         }
465         kfree(entries);
466 
467         return err;
468 }
469 #endif
470 
471 #ifdef CONFIG_SCHED_INFO
472 /*
473  * Provides /proc/PID/schedstat
474  */
475 static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
476                               struct pid *pid, struct task_struct *task)
477 {
478         if (unlikely(!sched_info_on()))
479                 seq_puts(m, "0 0 0\n");
480         else
481                 seq_printf(m, "%llu %llu %lu\n",
482                    (unsigned long long)task->se.sum_exec_runtime,
483                    (unsigned long long)task->sched_info.run_delay,
484                    task->sched_info.pcount);
485 
486         return 0;
487 }
488 #endif
489 
490 #ifdef CONFIG_LATENCYTOP
491 static int lstats_show_proc(struct seq_file *m, void *v)
492 {
493         int i;
494         struct inode *inode = m->private;
495         struct task_struct *task = get_proc_task(inode);
496 
497         if (!task)
498                 return -ESRCH;
499         seq_puts(m, "Latency Top version : v0.1\n");
500         for (i = 0; i < LT_SAVECOUNT; i++) {
501                 struct latency_record *lr = &task->latency_record[i];
502                 if (lr->backtrace[0]) {
503                         int q;
504                         seq_printf(m, "%i %li %li",
505                                    lr->count, lr->time, lr->max);
506                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
507                                 unsigned long bt = lr->backtrace[q];
508 
509                                 if (!bt)
510                                         break;
511                                 seq_printf(m, " %ps", (void *)bt);
512                         }
513                         seq_putc(m, '\n');
514                 }
515 
516         }
517         put_task_struct(task);
518         return 0;
519 }
520 
521 static int lstats_open(struct inode *inode, struct file *file)
522 {
523         return single_open(file, lstats_show_proc, inode);
524 }
525 
526 static ssize_t lstats_write(struct file *file, const char __user *buf,
527                             size_t count, loff_t *offs)
528 {
529         struct task_struct *task = get_proc_task(file_inode(file));
530 
531         if (!task)
532                 return -ESRCH;
533         clear_tsk_latency_tracing(task);
534         put_task_struct(task);
535 
536         return count;
537 }
538 
539 static const struct file_operations proc_lstats_operations = {
540         .open           = lstats_open,
541         .read           = seq_read,
542         .write          = lstats_write,
543         .llseek         = seq_lseek,
544         .release        = single_release,
545 };
546 
547 #endif
548 
549 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
550                           struct pid *pid, struct task_struct *task)
551 {
552         unsigned long totalpages = totalram_pages() + total_swap_pages;
553         unsigned long points = 0;
554 
555         points = oom_badness(task, totalpages) * 1000 / totalpages;
556         seq_printf(m, "%lu\n", points);
557 
558         return 0;
559 }
560 
561 struct limit_names {
562         const char *name;
563         const char *unit;
564 };
565 
566 static const struct limit_names lnames[RLIM_NLIMITS] = {
567         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
568         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
569         [RLIMIT_DATA] = {"Max data size", "bytes"},
570         [RLIMIT_STACK] = {"Max stack size", "bytes"},
571         [RLIMIT_CORE] = {"Max core file size", "bytes"},
572         [RLIMIT_RSS] = {"Max resident set", "bytes"},
573         [RLIMIT_NPROC] = {"Max processes", "processes"},
574         [RLIMIT_NOFILE] = {"Max open files", "files"},
575         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
576         [RLIMIT_AS] = {"Max address space", "bytes"},
577         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
578         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
579         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
580         [RLIMIT_NICE] = {"Max nice priority", NULL},
581         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
582         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
583 };
584 
585 /* Display limits for a process */
586 static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
587                            struct pid *pid, struct task_struct *task)
588 {
589         unsigned int i;
590         unsigned long flags;
591 
592         struct rlimit rlim[RLIM_NLIMITS];
593 
594         if (!lock_task_sighand(task, &flags))
595                 return 0;
596         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
597         unlock_task_sighand(task, &flags);
598 
599         /*
600          * print the file header
601          */
602         seq_puts(m, "Limit                     "
603                 "Soft Limit           "
604                 "Hard Limit           "
605                 "Units     \n");
606 
607         for (i = 0; i < RLIM_NLIMITS; i++) {
608                 if (rlim[i].rlim_cur == RLIM_INFINITY)
609                         seq_printf(m, "%-25s %-20s ",
610                                    lnames[i].name, "unlimited");
611                 else
612                         seq_printf(m, "%-25s %-20lu ",
613                                    lnames[i].name, rlim[i].rlim_cur);
614 
615                 if (rlim[i].rlim_max == RLIM_INFINITY)
616                         seq_printf(m, "%-20s ", "unlimited");
617                 else
618                         seq_printf(m, "%-20lu ", rlim[i].rlim_max);
619 
620                 if (lnames[i].unit)
621                         seq_printf(m, "%-10s\n", lnames[i].unit);
622                 else
623                         seq_putc(m, '\n');
624         }
625 
626         return 0;
627 }
628 
629 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
630 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
631                             struct pid *pid, struct task_struct *task)
632 {
633         struct syscall_info info;
634         u64 *args = &info.data.args[0];
635         int res;
636 
637         res = lock_trace(task);
638         if (res)
639                 return res;
640 
641         if (task_current_syscall(task, &info))
642                 seq_puts(m, "running\n");
643         else if (info.data.nr < 0)
644                 seq_printf(m, "%d 0x%llx 0x%llx\n",
645                            info.data.nr, info.sp, info.data.instruction_pointer);
646         else
647                 seq_printf(m,
648                        "%d 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx\n",
649                        info.data.nr,
650                        args[0], args[1], args[2], args[3], args[4], args[5],
651                        info.sp, info.data.instruction_pointer);
652         unlock_trace(task);
653 
654         return 0;
655 }
656 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
657 
658 /************************************************************************/
659 /*                       Here the fs part begins                        */
660 /************************************************************************/
661 
662 /* permission checks */
663 static int proc_fd_access_allowed(struct inode *inode)
664 {
665         struct task_struct *task;
666         int allowed = 0;
667         /* Allow access to a task's file descriptors if it is us or we
668          * may use ptrace attach to the process and find out that
669          * information.
670          */
671         task = get_proc_task(inode);
672         if (task) {
673                 allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
674                 put_task_struct(task);
675         }
676         return allowed;
677 }
678 
679 int proc_setattr(struct dentry *dentry, struct iattr *attr)
680 {
681         int error;
682         struct inode *inode = d_inode(dentry);
683 
684         if (attr->ia_valid & ATTR_MODE)
685                 return -EPERM;
686 
687         error = setattr_prepare(dentry, attr);
688         if (error)
689                 return error;
690 
691         setattr_copy(inode, attr);
692         mark_inode_dirty(inode);
693         return 0;
694 }
695 
696 /*
697  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
698  * or euid/egid (for hide_pid_min=2)?
699  */
700 static bool has_pid_permissions(struct pid_namespace *pid,
701                                  struct task_struct *task,
702                                  int hide_pid_min)
703 {
704         if (pid->hide_pid < hide_pid_min)
705                 return true;
706         if (in_group_p(pid->pid_gid))
707                 return true;
708         return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
709 }
710 
711 
712 static int proc_pid_permission(struct inode *inode, int mask)
713 {
714         struct pid_namespace *pid = proc_pid_ns(inode);
715         struct task_struct *task;
716         bool has_perms;
717 
718         task = get_proc_task(inode);
719         if (!task)
720                 return -ESRCH;
721         has_perms = has_pid_permissions(pid, task, HIDEPID_NO_ACCESS);
722         put_task_struct(task);
723 
724         if (!has_perms) {
725                 if (pid->hide_pid == HIDEPID_INVISIBLE) {
726                         /*
727                          * Let's make getdents(), stat(), and open()
728                          * consistent with each other.  If a process
729                          * may not stat() a file, it shouldn't be seen
730                          * in procfs at all.
731                          */
732                         return -ENOENT;
733                 }
734 
735                 return -EPERM;
736         }
737         return generic_permission(inode, mask);
738 }
739 
740 
741 
742 static const struct inode_operations proc_def_inode_operations = {
743         .setattr        = proc_setattr,
744 };
745 
746 static int proc_single_show(struct seq_file *m, void *v)
747 {
748         struct inode *inode = m->private;
749         struct pid_namespace *ns = proc_pid_ns(inode);
750         struct pid *pid = proc_pid(inode);
751         struct task_struct *task;
752         int ret;
753 
754         task = get_pid_task(pid, PIDTYPE_PID);
755         if (!task)
756                 return -ESRCH;
757 
758         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
759 
760         put_task_struct(task);
761         return ret;
762 }
763 
764 static int proc_single_open(struct inode *inode, struct file *filp)
765 {
766         return single_open(filp, proc_single_show, inode);
767 }
768 
769 static const struct file_operations proc_single_file_operations = {
770         .open           = proc_single_open,
771         .read           = seq_read,
772         .llseek         = seq_lseek,
773         .release        = single_release,
774 };
775 
776 
777 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
778 {
779         struct task_struct *task = get_proc_task(inode);
780         struct mm_struct *mm = ERR_PTR(-ESRCH);
781 
782         if (task) {
783                 mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
784                 put_task_struct(task);
785 
786                 if (!IS_ERR_OR_NULL(mm)) {
787                         /* ensure this mm_struct can't be freed */
788                         mmgrab(mm);
789                         /* but do not pin its memory */
790                         mmput(mm);
791                 }
792         }
793 
794         return mm;
795 }
796 
797 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
798 {
799         struct mm_struct *mm = proc_mem_open(inode, mode);
800 
801         if (IS_ERR(mm))
802                 return PTR_ERR(mm);
803 
804         file->private_data = mm;
805         return 0;
806 }
807 
808 static int mem_open(struct inode *inode, struct file *file)
809 {
810         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
811 
812         /* OK to pass negative loff_t, we can catch out-of-range */
813         file->f_mode |= FMODE_UNSIGNED_OFFSET;
814 
815         return ret;
816 }
817 
818 static ssize_t mem_rw(struct file *file, char __user *buf,
819                         size_t count, loff_t *ppos, int write)
820 {
821         struct mm_struct *mm = file->private_data;
822         unsigned long addr = *ppos;
823         ssize_t copied;
824         char *page;
825         unsigned int flags;
826 
827         if (!mm)
828                 return 0;
829 
830         page = (char *)__get_free_page(GFP_KERNEL);
831         if (!page)
832                 return -ENOMEM;
833 
834         copied = 0;
835         if (!mmget_not_zero(mm))
836                 goto free;
837 
838         flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
839 
840         while (count > 0) {
841                 int this_len = min_t(int, count, PAGE_SIZE);
842 
843                 if (write && copy_from_user(page, buf, this_len)) {
844                         copied = -EFAULT;
845                         break;
846                 }
847 
848                 this_len = access_remote_vm(mm, addr, page, this_len, flags);
849                 if (!this_len) {
850                         if (!copied)
851                                 copied = -EIO;
852                         break;
853                 }
854 
855                 if (!write && copy_to_user(buf, page, this_len)) {
856                         copied = -EFAULT;
857                         break;
858                 }
859 
860                 buf += this_len;
861                 addr += this_len;
862                 copied += this_len;
863                 count -= this_len;
864         }
865         *ppos = addr;
866 
867         mmput(mm);
868 free:
869         free_page((unsigned long) page);
870         return copied;
871 }
872 
873 static ssize_t mem_read(struct file *file, char __user *buf,
874                         size_t count, loff_t *ppos)
875 {
876         return mem_rw(file, buf, count, ppos, 0);
877 }
878 
879 static ssize_t mem_write(struct file *file, const char __user *buf,
880                          size_t count, loff_t *ppos)
881 {
882         return mem_rw(file, (char __user*)buf, count, ppos, 1);
883 }
884 
885 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
886 {
887         switch (orig) {
888         case 0:
889                 file->f_pos = offset;
890                 break;
891         case 1:
892                 file->f_pos += offset;
893                 break;
894         default:
895                 return -EINVAL;
896         }
897         force_successful_syscall_return();
898         return file->f_pos;
899 }
900 
901 static int mem_release(struct inode *inode, struct file *file)
902 {
903         struct mm_struct *mm = file->private_data;
904         if (mm)
905                 mmdrop(mm);
906         return 0;
907 }
908 
909 static const struct file_operations proc_mem_operations = {
910         .llseek         = mem_lseek,
911         .read           = mem_read,
912         .write          = mem_write,
913         .open           = mem_open,
914         .release        = mem_release,
915 };
916 
917 static int environ_open(struct inode *inode, struct file *file)
918 {
919         return __mem_open(inode, file, PTRACE_MODE_READ);
920 }
921 
922 static ssize_t environ_read(struct file *file, char __user *buf,
923                         size_t count, loff_t *ppos)
924 {
925         char *page;
926         unsigned long src = *ppos;
927         int ret = 0;
928         struct mm_struct *mm = file->private_data;
929         unsigned long env_start, env_end;
930 
931         /* Ensure the process spawned far enough to have an environment. */
932         if (!mm || !mm->env_end)
933                 return 0;
934 
935         page = (char *)__get_free_page(GFP_KERNEL);
936         if (!page)
937                 return -ENOMEM;
938 
939         ret = 0;
940         if (!mmget_not_zero(mm))
941                 goto free;
942 
943         spin_lock(&mm->arg_lock);
944         env_start = mm->env_start;
945         env_end = mm->env_end;
946         spin_unlock(&mm->arg_lock);
947 
948         while (count > 0) {
949                 size_t this_len, max_len;
950                 int retval;
951 
952                 if (src >= (env_end - env_start))
953                         break;
954 
955                 this_len = env_end - (env_start + src);
956 
957                 max_len = min_t(size_t, PAGE_SIZE, count);
958                 this_len = min(max_len, this_len);
959 
960                 retval = access_remote_vm(mm, (env_start + src), page, this_len, FOLL_ANON);
961 
962                 if (retval <= 0) {
963                         ret = retval;
964                         break;
965                 }
966 
967                 if (copy_to_user(buf, page, retval)) {
968                         ret = -EFAULT;
969                         break;
970                 }
971 
972                 ret += retval;
973                 src += retval;
974                 buf += retval;
975                 count -= retval;
976         }
977         *ppos = src;
978         mmput(mm);
979 
980 free:
981         free_page((unsigned long) page);
982         return ret;
983 }
984 
985 static const struct file_operations proc_environ_operations = {
986         .open           = environ_open,
987         .read           = environ_read,
988         .llseek         = generic_file_llseek,
989         .release        = mem_release,
990 };
991 
992 static int auxv_open(struct inode *inode, struct file *file)
993 {
994         return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
995 }
996 
997 static ssize_t auxv_read(struct file *file, char __user *buf,
998                         size_t count, loff_t *ppos)
999 {
1000         struct mm_struct *mm = file->private_data;
1001         unsigned int nwords = 0;
1002 
1003         if (!mm)
1004                 return 0;
1005         do {
1006                 nwords += 2;
1007         } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
1008         return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
1009                                        nwords * sizeof(mm->saved_auxv[0]));
1010 }
1011 
1012 static const struct file_operations proc_auxv_operations = {
1013         .open           = auxv_open,
1014         .read           = auxv_read,
1015         .llseek         = generic_file_llseek,
1016         .release        = mem_release,
1017 };
1018 
1019 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
1020                             loff_t *ppos)
1021 {
1022         struct task_struct *task = get_proc_task(file_inode(file));
1023         char buffer[PROC_NUMBUF];
1024         int oom_adj = OOM_ADJUST_MIN;
1025         size_t len;
1026 
1027         if (!task)
1028                 return -ESRCH;
1029         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
1030                 oom_adj = OOM_ADJUST_MAX;
1031         else
1032                 oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
1033                           OOM_SCORE_ADJ_MAX;
1034         put_task_struct(task);
1035         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
1036         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1037 }
1038 
1039 static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
1040 {
1041         static DEFINE_MUTEX(oom_adj_mutex);
1042         struct mm_struct *mm = NULL;
1043         struct task_struct *task;
1044         int err = 0;
1045 
1046         task = get_proc_task(file_inode(file));
1047         if (!task)
1048                 return -ESRCH;
1049 
1050         mutex_lock(&oom_adj_mutex);
1051         if (legacy) {
1052                 if (oom_adj < task->signal->oom_score_adj &&
1053                                 !capable(CAP_SYS_RESOURCE)) {
1054                         err = -EACCES;
1055                         goto err_unlock;
1056                 }
1057                 /*
1058                  * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
1059                  * /proc/pid/oom_score_adj instead.
1060                  */
1061                 pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
1062                           current->comm, task_pid_nr(current), task_pid_nr(task),
1063                           task_pid_nr(task));
1064         } else {
1065                 if ((short)oom_adj < task->signal->oom_score_adj_min &&
1066                                 !capable(CAP_SYS_RESOURCE)) {
1067                         err = -EACCES;
1068                         goto err_unlock;
1069                 }
1070         }
1071 
1072         /*
1073          * Make sure we will check other processes sharing the mm if this is
1074          * not vfrok which wants its own oom_score_adj.
1075          * pin the mm so it doesn't go away and get reused after task_unlock
1076          */
1077         if (!task->vfork_done) {
1078                 struct task_struct *p = find_lock_task_mm(task);
1079 
1080                 if (p) {
1081                         if (atomic_read(&p->mm->mm_users) > 1) {
1082                                 mm = p->mm;
1083                                 mmgrab(mm);
1084                         }
1085                         task_unlock(p);
1086                 }
1087         }
1088 
1089         task->signal->oom_score_adj = oom_adj;
1090         if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1091                 task->signal->oom_score_adj_min = (short)oom_adj;
1092         trace_oom_score_adj_update(task);
1093 
1094         if (mm) {
1095                 struct task_struct *p;
1096 
1097                 rcu_read_lock();
1098                 for_each_process(p) {
1099                         if (same_thread_group(task, p))
1100                                 continue;
1101 
1102                         /* do not touch kernel threads or the global init */
1103                         if (p->flags & PF_KTHREAD || is_global_init(p))
1104                                 continue;
1105 
1106                         task_lock(p);
1107                         if (!p->vfork_done && process_shares_mm(p, mm)) {
1108                                 p->signal->oom_score_adj = oom_adj;
1109                                 if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
1110                                         p->signal->oom_score_adj_min = (short)oom_adj;
1111                         }
1112                         task_unlock(p);
1113                 }
1114                 rcu_read_unlock();
1115                 mmdrop(mm);
1116         }
1117 err_unlock:
1118         mutex_unlock(&oom_adj_mutex);
1119         put_task_struct(task);
1120         return err;
1121 }
1122 
1123 /*
1124  * /proc/pid/oom_adj exists solely for backwards compatibility with previous
1125  * kernels.  The effective policy is defined by oom_score_adj, which has a
1126  * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
1127  * Values written to oom_adj are simply mapped linearly to oom_score_adj.
1128  * Processes that become oom disabled via oom_adj will still be oom disabled
1129  * with this implementation.
1130  *
1131  * oom_adj cannot be removed since existing userspace binaries use it.
1132  */
1133 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
1134                              size_t count, loff_t *ppos)
1135 {
1136         char buffer[PROC_NUMBUF];
1137         int oom_adj;
1138         int err;
1139 
1140         memset(buffer, 0, sizeof(buffer));
1141         if (count > sizeof(buffer) - 1)
1142                 count = sizeof(buffer) - 1;
1143         if (copy_from_user(buffer, buf, count)) {
1144                 err = -EFAULT;
1145                 goto out;
1146         }
1147 
1148         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
1149         if (err)
1150                 goto out;
1151         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
1152              oom_adj != OOM_DISABLE) {
1153                 err = -EINVAL;
1154                 goto out;
1155         }
1156 
1157         /*
1158          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1159          * value is always attainable.
1160          */
1161         if (oom_adj == OOM_ADJUST_MAX)
1162                 oom_adj = OOM_SCORE_ADJ_MAX;
1163         else
1164                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
1165 
1166         err = __set_oom_adj(file, oom_adj, true);
1167 out:
1168         return err < 0 ? err : count;
1169 }
1170 
1171 static const struct file_operations proc_oom_adj_operations = {
1172         .read           = oom_adj_read,
1173         .write          = oom_adj_write,
1174         .llseek         = generic_file_llseek,
1175 };
1176 
1177 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1178                                         size_t count, loff_t *ppos)
1179 {
1180         struct task_struct *task = get_proc_task(file_inode(file));
1181         char buffer[PROC_NUMBUF];
1182         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1183         size_t len;
1184 
1185         if (!task)
1186                 return -ESRCH;
1187         oom_score_adj = task->signal->oom_score_adj;
1188         put_task_struct(task);
1189         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1190         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1191 }
1192 
1193 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1194                                         size_t count, loff_t *ppos)
1195 {
1196         char buffer[PROC_NUMBUF];
1197         int oom_score_adj;
1198         int err;
1199 
1200         memset(buffer, 0, sizeof(buffer));
1201         if (count > sizeof(buffer) - 1)
1202                 count = sizeof(buffer) - 1;
1203         if (copy_from_user(buffer, buf, count)) {
1204                 err = -EFAULT;
1205                 goto out;
1206         }
1207 
1208         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1209         if (err)
1210                 goto out;
1211         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1212                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1213                 err = -EINVAL;
1214                 goto out;
1215         }
1216 
1217         err = __set_oom_adj(file, oom_score_adj, false);
1218 out:
1219         return err < 0 ? err : count;
1220 }
1221 
1222 static const struct file_operations proc_oom_score_adj_operations = {
1223         .read           = oom_score_adj_read,
1224         .write          = oom_score_adj_write,
1225         .llseek         = default_llseek,
1226 };
1227 
1228 #ifdef CONFIG_AUDIT
1229 #define TMPBUFLEN 11
1230 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1231                                   size_t count, loff_t *ppos)
1232 {
1233         struct inode * inode = file_inode(file);
1234         struct task_struct *task = get_proc_task(inode);
1235         ssize_t length;
1236         char tmpbuf[TMPBUFLEN];
1237 
1238         if (!task)
1239                 return -ESRCH;
1240         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1241                            from_kuid(file->f_cred->user_ns,
1242                                      audit_get_loginuid(task)));
1243         put_task_struct(task);
1244         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1245 }
1246 
1247 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1248                                    size_t count, loff_t *ppos)
1249 {
1250         struct inode * inode = file_inode(file);
1251         uid_t loginuid;
1252         kuid_t kloginuid;
1253         int rv;
1254 
1255         rcu_read_lock();
1256         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1257                 rcu_read_unlock();
1258                 return -EPERM;
1259         }
1260         rcu_read_unlock();
1261 
1262         if (*ppos != 0) {
1263                 /* No partial writes. */
1264                 return -EINVAL;
1265         }
1266 
1267         rv = kstrtou32_from_user(buf, count, 10, &loginuid);
1268         if (rv < 0)
1269                 return rv;
1270 
1271         /* is userspace tring to explicitly UNSET the loginuid? */
1272         if (loginuid == AUDIT_UID_UNSET) {
1273                 kloginuid = INVALID_UID;
1274         } else {
1275                 kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1276                 if (!uid_valid(kloginuid))
1277                         return -EINVAL;
1278         }
1279 
1280         rv = audit_set_loginuid(kloginuid);
1281         if (rv < 0)
1282                 return rv;
1283         return count;
1284 }
1285 
1286 static const struct file_operations proc_loginuid_operations = {
1287         .read           = proc_loginuid_read,
1288         .write          = proc_loginuid_write,
1289         .llseek         = generic_file_llseek,
1290 };
1291 
1292 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1293                                   size_t count, loff_t *ppos)
1294 {
1295         struct inode * inode = file_inode(file);
1296         struct task_struct *task = get_proc_task(inode);
1297         ssize_t length;
1298         char tmpbuf[TMPBUFLEN];
1299 
1300         if (!task)
1301                 return -ESRCH;
1302         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1303                                 audit_get_sessionid(task));
1304         put_task_struct(task);
1305         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1306 }
1307 
1308 static const struct file_operations proc_sessionid_operations = {
1309         .read           = proc_sessionid_read,
1310         .llseek         = generic_file_llseek,
1311 };
1312 #endif
1313 
1314 #ifdef CONFIG_FAULT_INJECTION
1315 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1316                                       size_t count, loff_t *ppos)
1317 {
1318         struct task_struct *task = get_proc_task(file_inode(file));
1319         char buffer[PROC_NUMBUF];
1320         size_t len;
1321         int make_it_fail;
1322 
1323         if (!task)
1324                 return -ESRCH;
1325         make_it_fail = task->make_it_fail;
1326         put_task_struct(task);
1327 
1328         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1329 
1330         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1331 }
1332 
1333 static ssize_t proc_fault_inject_write(struct file * file,
1334                         const char __user * buf, size_t count, loff_t *ppos)
1335 {
1336         struct task_struct *task;
1337         char buffer[PROC_NUMBUF];
1338         int make_it_fail;
1339         int rv;
1340 
1341         if (!capable(CAP_SYS_RESOURCE))
1342                 return -EPERM;
1343         memset(buffer, 0, sizeof(buffer));
1344         if (count > sizeof(buffer) - 1)
1345                 count = sizeof(buffer) - 1;
1346         if (copy_from_user(buffer, buf, count))
1347                 return -EFAULT;
1348         rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
1349         if (rv < 0)
1350                 return rv;
1351         if (make_it_fail < 0 || make_it_fail > 1)
1352                 return -EINVAL;
1353 
1354         task = get_proc_task(file_inode(file));
1355         if (!task)
1356                 return -ESRCH;
1357         task->make_it_fail = make_it_fail;
1358         put_task_struct(task);
1359 
1360         return count;
1361 }
1362 
1363 static const struct file_operations proc_fault_inject_operations = {
1364         .read           = proc_fault_inject_read,
1365         .write          = proc_fault_inject_write,
1366         .llseek         = generic_file_llseek,
1367 };
1368 
1369 static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
1370                                    size_t count, loff_t *ppos)
1371 {
1372         struct task_struct *task;
1373         int err;
1374         unsigned int n;
1375 
1376         err = kstrtouint_from_user(buf, count, 0, &n);
1377         if (err)
1378                 return err;
1379 
1380         task = get_proc_task(file_inode(file));
1381         if (!task)
1382                 return -ESRCH;
1383         task->fail_nth = n;
1384         put_task_struct(task);
1385 
1386         return count;
1387 }
1388 
1389 static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
1390                                   size_t count, loff_t *ppos)
1391 {
1392         struct task_struct *task;
1393         char numbuf[PROC_NUMBUF];
1394         ssize_t len;
1395 
1396         task = get_proc_task(file_inode(file));
1397         if (!task)
1398                 return -ESRCH;
1399         len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
1400         put_task_struct(task);
1401         return simple_read_from_buffer(buf, count, ppos, numbuf, len);
1402 }
1403 
1404 static const struct file_operations proc_fail_nth_operations = {
1405         .read           = proc_fail_nth_read,
1406         .write          = proc_fail_nth_write,
1407 };
1408 #endif
1409 
1410 
1411 #ifdef CONFIG_SCHED_DEBUG
1412 /*
1413  * Print out various scheduling related per-task fields:
1414  */
1415 static int sched_show(struct seq_file *m, void *v)
1416 {
1417         struct inode *inode = m->private;
1418         struct pid_namespace *ns = proc_pid_ns(inode);
1419         struct task_struct *p;
1420 
1421         p = get_proc_task(inode);
1422         if (!p)
1423                 return -ESRCH;
1424         proc_sched_show_task(p, ns, m);
1425 
1426         put_task_struct(p);
1427 
1428         return 0;
1429 }
1430 
1431 static ssize_t
1432 sched_write(struct file *file, const char __user *buf,
1433             size_t count, loff_t *offset)
1434 {
1435         struct inode *inode = file_inode(file);
1436         struct task_struct *p;
1437 
1438         p = get_proc_task(inode);
1439         if (!p)
1440                 return -ESRCH;
1441         proc_sched_set_task(p);
1442 
1443         put_task_struct(p);
1444 
1445         return count;
1446 }
1447 
1448 static int sched_open(struct inode *inode, struct file *filp)
1449 {
1450         return single_open(filp, sched_show, inode);
1451 }
1452 
1453 static const struct file_operations proc_pid_sched_operations = {
1454         .open           = sched_open,
1455         .read           = seq_read,
1456         .write          = sched_write,
1457         .llseek         = seq_lseek,
1458         .release        = single_release,
1459 };
1460 
1461 #endif
1462 
1463 #ifdef CONFIG_SCHED_AUTOGROUP
1464 /*
1465  * Print out autogroup related information:
1466  */
1467 static int sched_autogroup_show(struct seq_file *m, void *v)
1468 {
1469         struct inode *inode = m->private;
1470         struct task_struct *p;
1471 
1472         p = get_proc_task(inode);
1473         if (!p)
1474                 return -ESRCH;
1475         proc_sched_autogroup_show_task(p, m);
1476 
1477         put_task_struct(p);
1478 
1479         return 0;
1480 }
1481 
1482 static ssize_t
1483 sched_autogroup_write(struct file *file, const char __user *buf,
1484             size_t count, loff_t *offset)
1485 {
1486         struct inode *inode = file_inode(file);
1487         struct task_struct *p;
1488         char buffer[PROC_NUMBUF];
1489         int nice;
1490         int err;
1491 
1492         memset(buffer, 0, sizeof(buffer));
1493         if (count > sizeof(buffer) - 1)
1494                 count = sizeof(buffer) - 1;
1495         if (copy_from_user(buffer, buf, count))
1496                 return -EFAULT;
1497 
1498         err = kstrtoint(strstrip(buffer), 0, &nice);
1499         if (err < 0)
1500                 return err;
1501 
1502         p = get_proc_task(inode);
1503         if (!p)
1504                 return -ESRCH;
1505 
1506         err = proc_sched_autogroup_set_nice(p, nice);
1507         if (err)
1508                 count = err;
1509 
1510         put_task_struct(p);
1511 
1512         return count;
1513 }
1514 
1515 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1516 {
1517         int ret;
1518 
1519         ret = single_open(filp, sched_autogroup_show, NULL);
1520         if (!ret) {
1521                 struct seq_file *m = filp->private_data;
1522 
1523                 m->private = inode;
1524         }
1525         return ret;
1526 }
1527 
1528 static const struct file_operations proc_pid_sched_autogroup_operations = {
1529         .open           = sched_autogroup_open,
1530         .read           = seq_read,
1531         .write          = sched_autogroup_write,
1532         .llseek         = seq_lseek,
1533         .release        = single_release,
1534 };
1535 
1536 #endif /* CONFIG_SCHED_AUTOGROUP */
1537 
1538 #ifdef CONFIG_TIME_NS
1539 static int timens_offsets_show(struct seq_file *m, void *v)
1540 {
1541         struct task_struct *p;
1542 
1543         p = get_proc_task(file_inode(m->file));
1544         if (!p)
1545                 return -ESRCH;
1546         proc_timens_show_offsets(p, m);
1547 
1548         put_task_struct(p);
1549 
1550         return 0;
1551 }
1552 
1553 static ssize_t timens_offsets_write(struct file *file, const char __user *buf,
1554                                     size_t count, loff_t *ppos)
1555 {
1556         struct inode *inode = file_inode(file);
1557         struct proc_timens_offset offsets[2];
1558         char *kbuf = NULL, *pos, *next_line;
1559         struct task_struct *p;
1560         int ret, noffsets;
1561 
1562         /* Only allow < page size writes at the beginning of the file */
1563         if ((*ppos != 0) || (count >= PAGE_SIZE))
1564                 return -EINVAL;
1565 
1566         /* Slurp in the user data */
1567         kbuf = memdup_user_nul(buf, count);
1568         if (IS_ERR(kbuf))
1569                 return PTR_ERR(kbuf);
1570 
1571         /* Parse the user data */
1572         ret = -EINVAL;
1573         noffsets = 0;
1574         for (pos = kbuf; pos; pos = next_line) {
1575                 struct proc_timens_offset *off = &offsets[noffsets];
1576                 char clock[10];
1577                 int err;
1578 
1579                 /* Find the end of line and ensure we don't look past it */
1580                 next_line = strchr(pos, '\n');
1581                 if (next_line) {
1582                         *next_line = '\0';
1583                         next_line++;
1584                         if (*next_line == '\0')
1585                                 next_line = NULL;
1586                 }
1587 
1588                 err = sscanf(pos, "%9s %lld %lu", clock,
1589                                 &off->val.tv_sec, &off->val.tv_nsec);
1590                 if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC)
1591                         goto out;
1592 
1593                 clock[sizeof(clock) - 1] = 0;
1594                 if (strcmp(clock, "monotonic") == 0 ||
1595                     strcmp(clock, __stringify(CLOCK_MONOTONIC)) == 0)
1596                         off->clockid = CLOCK_MONOTONIC;
1597                 else if (strcmp(clock, "boottime") == 0 ||
1598                          strcmp(clock, __stringify(CLOCK_BOOTTIME)) == 0)
1599                         off->clockid = CLOCK_BOOTTIME;
1600                 else
1601                         goto out;
1602 
1603                 noffsets++;
1604                 if (noffsets == ARRAY_SIZE(offsets)) {
1605                         if (next_line)
1606                                 count = next_line - kbuf;
1607                         break;
1608                 }
1609         }
1610 
1611         ret = -ESRCH;
1612         p = get_proc_task(inode);
1613         if (!p)
1614                 goto out;
1615         ret = proc_timens_set_offset(file, p, offsets, noffsets);
1616         put_task_struct(p);
1617         if (ret)
1618                 goto out;
1619 
1620         ret = count;
1621 out:
1622         kfree(kbuf);
1623         return ret;
1624 }
1625 
1626 static int timens_offsets_open(struct inode *inode, struct file *filp)
1627 {
1628         return single_open(filp, timens_offsets_show, inode);
1629 }
1630 
1631 static const struct file_operations proc_timens_offsets_operations = {
1632         .open           = timens_offsets_open,
1633         .read           = seq_read,
1634         .write          = timens_offsets_write,
1635         .llseek         = seq_lseek,
1636         .release        = single_release,
1637 };
1638 #endif /* CONFIG_TIME_NS */
1639 
1640 static ssize_t comm_write(struct file *file, const char __user *buf,
1641                                 size_t count, loff_t *offset)
1642 {
1643         struct inode *inode = file_inode(file);
1644         struct task_struct *p;
1645         char buffer[TASK_COMM_LEN];
1646         const size_t maxlen = sizeof(buffer) - 1;
1647 
1648         memset(buffer, 0, sizeof(buffer));
1649         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1650                 return -EFAULT;
1651 
1652         p = get_proc_task(inode);
1653         if (!p)
1654                 return -ESRCH;
1655 
1656         if (same_thread_group(current, p))
1657                 set_task_comm(p, buffer);
1658         else
1659                 count = -EINVAL;
1660 
1661         put_task_struct(p);
1662 
1663         return count;
1664 }
1665 
1666 static int comm_show(struct seq_file *m, void *v)
1667 {
1668         struct inode *inode = m->private;
1669         struct task_struct *p;
1670 
1671         p = get_proc_task(inode);
1672         if (!p)
1673                 return -ESRCH;
1674 
1675         proc_task_name(m, p, false);
1676         seq_putc(m, '\n');
1677 
1678         put_task_struct(p);
1679 
1680         return 0;
1681 }
1682 
1683 static int comm_open(struct inode *inode, struct file *filp)
1684 {
1685         return single_open(filp, comm_show, inode);
1686 }
1687 
1688 static const struct file_operations proc_pid_set_comm_operations = {
1689         .open           = comm_open,
1690         .read           = seq_read,
1691         .write          = comm_write,
1692         .llseek         = seq_lseek,
1693         .release        = single_release,
1694 };
1695 
1696 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1697 {
1698         struct task_struct *task;
1699         struct file *exe_file;
1700 
1701         task = get_proc_task(d_inode(dentry));
1702         if (!task)
1703                 return -ENOENT;
1704         exe_file = get_task_exe_file(task);
1705         put_task_struct(task);
1706         if (exe_file) {
1707                 *exe_path = exe_file->f_path;
1708                 path_get(&exe_file->f_path);
1709                 fput(exe_file);
1710                 return 0;
1711         } else
1712                 return -ENOENT;
1713 }
1714 
1715 static const char *proc_pid_get_link(struct dentry *dentry,
1716                                      struct inode *inode,
1717                                      struct delayed_call *done)
1718 {
1719         struct path path;
1720         int error = -EACCES;
1721 
1722         if (!dentry)
1723                 return ERR_PTR(-ECHILD);
1724 
1725         /* Are we allowed to snoop on the tasks file descriptors? */
1726         if (!proc_fd_access_allowed(inode))
1727                 goto out;
1728 
1729         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1730         if (error)
1731                 goto out;
1732 
1733         error = nd_jump_link(&path);
1734 out:
1735         return ERR_PTR(error);
1736 }
1737 
1738 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1739 {
1740         char *tmp = (char *)__get_free_page(GFP_KERNEL);
1741         char *pathname;
1742         int len;
1743 
1744         if (!tmp)
1745                 return -ENOMEM;
1746 
1747         pathname = d_path(path, tmp, PAGE_SIZE);
1748         len = PTR_ERR(pathname);
1749         if (IS_ERR(pathname))
1750                 goto out;
1751         len = tmp + PAGE_SIZE - 1 - pathname;
1752 
1753         if (len > buflen)
1754                 len = buflen;
1755         if (copy_to_user(buffer, pathname, len))
1756                 len = -EFAULT;
1757  out:
1758         free_page((unsigned long)tmp);
1759         return len;
1760 }
1761 
1762 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1763 {
1764         int error = -EACCES;
1765         struct inode *inode = d_inode(dentry);
1766         struct path path;
1767 
1768         /* Are we allowed to snoop on the tasks file descriptors? */
1769         if (!proc_fd_access_allowed(inode))
1770                 goto out;
1771 
1772         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1773         if (error)
1774                 goto out;
1775 
1776         error = do_proc_readlink(&path, buffer, buflen);
1777         path_put(&path);
1778 out:
1779         return error;
1780 }
1781 
1782 const struct inode_operations proc_pid_link_inode_operations = {
1783         .readlink       = proc_pid_readlink,
1784         .get_link       = proc_pid_get_link,
1785         .setattr        = proc_setattr,
1786 };
1787 
1788 
1789 /* building an inode */
1790 
1791 void task_dump_owner(struct task_struct *task, umode_t mode,
1792                      kuid_t *ruid, kgid_t *rgid)
1793 {
1794         /* Depending on the state of dumpable compute who should own a
1795          * proc file for a task.
1796          */
1797         const struct cred *cred;
1798         kuid_t uid;
1799         kgid_t gid;
1800 
1801         if (unlikely(task->flags & PF_KTHREAD)) {
1802                 *ruid = GLOBAL_ROOT_UID;
1803                 *rgid = GLOBAL_ROOT_GID;
1804                 return;
1805         }
1806 
1807         /* Default to the tasks effective ownership */
1808         rcu_read_lock();
1809         cred = __task_cred(task);
1810         uid = cred->euid;
1811         gid = cred->egid;
1812         rcu_read_unlock();
1813 
1814         /*
1815          * Before the /proc/pid/status file was created the only way to read
1816          * the effective uid of a /process was to stat /proc/pid.  Reading
1817          * /proc/pid/status is slow enough that procps and other packages
1818          * kept stating /proc/pid.  To keep the rules in /proc simple I have
1819          * made this apply to all per process world readable and executable
1820          * directories.
1821          */
1822         if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
1823                 struct mm_struct *mm;
1824                 task_lock(task);
1825                 mm = task->mm;
1826                 /* Make non-dumpable tasks owned by some root */
1827                 if (mm) {
1828                         if (get_dumpable(mm) != SUID_DUMP_USER) {
1829                                 struct user_namespace *user_ns = mm->user_ns;
1830 
1831                                 uid = make_kuid(user_ns, 0);
1832                                 if (!uid_valid(uid))
1833                                         uid = GLOBAL_ROOT_UID;
1834 
1835                                 gid = make_kgid(user_ns, 0);
1836                                 if (!gid_valid(gid))
1837                                         gid = GLOBAL_ROOT_GID;
1838                         }
1839                 } else {
1840                         uid = GLOBAL_ROOT_UID;
1841                         gid = GLOBAL_ROOT_GID;
1842                 }
1843                 task_unlock(task);
1844         }
1845         *ruid = uid;
1846         *rgid = gid;
1847 }
1848 
1849 struct inode *proc_pid_make_inode(struct super_block * sb,
1850                                   struct task_struct *task, umode_t mode)
1851 {
1852         struct inode * inode;
1853         struct proc_inode *ei;
1854 
1855         /* We need a new inode */
1856 
1857         inode = new_inode(sb);
1858         if (!inode)
1859                 goto out;
1860 
1861         /* Common stuff */
1862         ei = PROC_I(inode);
1863         inode->i_mode = mode;
1864         inode->i_ino = get_next_ino();
1865         inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1866         inode->i_op = &proc_def_inode_operations;
1867 
1868         /*
1869          * grab the reference to task.
1870          */
1871         ei->pid = get_task_pid(task, PIDTYPE_PID);
1872         if (!ei->pid)
1873                 goto out_unlock;
1874 
1875         task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
1876         security_task_to_inode(task, inode);
1877 
1878 out:
1879         return inode;
1880 
1881 out_unlock:
1882         iput(inode);
1883         return NULL;
1884 }
1885 
1886 int pid_getattr(const struct path *path, struct kstat *stat,
1887                 u32 request_mask, unsigned int query_flags)
1888 {
1889         struct inode *inode = d_inode(path->dentry);
1890         struct pid_namespace *pid = proc_pid_ns(inode);
1891         struct task_struct *task;
1892 
1893         generic_fillattr(inode, stat);
1894 
1895         stat->uid = GLOBAL_ROOT_UID;
1896         stat->gid = GLOBAL_ROOT_GID;
1897         rcu_read_lock();
1898         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1899         if (task) {
1900                 if (!has_pid_permissions(pid, task, HIDEPID_INVISIBLE)) {
1901                         rcu_read_unlock();
1902                         /*
1903                          * This doesn't prevent learning whether PID exists,
1904                          * it only makes getattr() consistent with readdir().
1905                          */
1906                         return -ENOENT;
1907                 }
1908                 task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
1909         }
1910         rcu_read_unlock();
1911         return 0;
1912 }
1913 
1914 /* dentry stuff */
1915 
1916 /*
1917  * Set <pid>/... inode ownership (can change due to setuid(), etc.)
1918  */
1919 void pid_update_inode(struct task_struct *task, struct inode *inode)
1920 {
1921         task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
1922 
1923         inode->i_mode &= ~(S_ISUID | S_ISGID);
1924         security_task_to_inode(task, inode);
1925 }
1926 
1927 /*
1928  * Rewrite the inode's ownerships here because the owning task may have
1929  * performed a setuid(), etc.
1930  *
1931  */
1932 static int pid_revalidate(struct dentry *dentry, unsigned int flags)
1933 {
1934         struct inode *inode;
1935         struct task_struct *task;
1936 
1937         if (flags & LOOKUP_RCU)
1938                 return -ECHILD;
1939 
1940         inode = d_inode(dentry);
1941         task = get_proc_task(inode);
1942 
1943         if (task) {
1944                 pid_update_inode(task, inode);
1945                 put_task_struct(task);
1946                 return 1;
1947         }
1948         return 0;
1949 }
1950 
1951 static inline bool proc_inode_is_dead(struct inode *inode)
1952 {
1953         return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
1954 }
1955 
1956 int pid_delete_dentry(const struct dentry *dentry)
1957 {
1958         /* Is the task we represent dead?
1959          * If so, then don't put the dentry on the lru list,
1960          * kill it immediately.
1961          */
1962         return proc_inode_is_dead(d_inode(dentry));
1963 }
1964 
1965 const struct dentry_operations pid_dentry_operations =
1966 {
1967         .d_revalidate   = pid_revalidate,
1968         .d_delete       = pid_delete_dentry,
1969 };
1970 
1971 /* Lookups */
1972 
1973 /*
1974  * Fill a directory entry.
1975  *
1976  * If possible create the dcache entry and derive our inode number and
1977  * file type from dcache entry.
1978  *
1979  * Since all of the proc inode numbers are dynamically generated, the inode
1980  * numbers do not exist until the inode is cache.  This means creating the
1981  * the dcache entry in readdir is necessary to keep the inode numbers
1982  * reported by readdir in sync with the inode numbers reported
1983  * by stat.
1984  */
1985 bool proc_fill_cache(struct file *file, struct dir_context *ctx,
1986         const char *name, unsigned int len,
1987         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1988 {
1989         struct dentry *child, *dir = file->f_path.dentry;
1990         struct qstr qname = QSTR_INIT(name, len);
1991         struct inode *inode;
1992         unsigned type = DT_UNKNOWN;
1993         ino_t ino = 1;
1994 
1995         child = d_hash_and_lookup(dir, &qname);
1996         if (!child) {
1997                 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1998                 child = d_alloc_parallel(dir, &qname, &wq);
1999                 if (IS_ERR(child))
2000                         goto end_instantiate;
2001                 if (d_in_lookup(child)) {
2002                         struct dentry *res;
2003                         res = instantiate(child, task, ptr);
2004                         d_lookup_done(child);
2005                         if (unlikely(res)) {
2006                                 dput(child);
2007                                 child = res;
2008                                 if (IS_ERR(child))
2009                                         goto end_instantiate;
2010                         }
2011                 }
2012         }
2013         inode = d_inode(child);
2014         ino = inode->i_ino;
2015         type = inode->i_mode >> 12;
2016         dput(child);
2017 end_instantiate:
2018         return dir_emit(ctx, name, len, ino, type);
2019 }
2020 
2021 /*
2022  * dname_to_vma_addr - maps a dentry name into two unsigned longs
2023  * which represent vma start and end addresses.
2024  */
2025 static int dname_to_vma_addr(struct dentry *dentry,
2026                              unsigned long *start, unsigned long *end)
2027 {
2028         const char *str = dentry->d_name.name;
2029         unsigned long long sval, eval;
2030         unsigned int len;
2031 
2032         if (str[0] == '' && str[1] != '-')
2033                 return -EINVAL;
2034         len = _parse_integer(str, 16, &sval);
2035         if (len & KSTRTOX_OVERFLOW)
2036                 return -EINVAL;
2037         if (sval != (unsigned long)sval)
2038                 return -EINVAL;
2039         str += len;
2040 
2041         if (*str != '-')
2042                 return -EINVAL;
2043         str++;
2044 
2045         if (str[0] == '' && str[1])
2046                 return -EINVAL;
2047         len = _parse_integer(str, 16, &eval);
2048         if (len & KSTRTOX_OVERFLOW)
2049                 return -EINVAL;
2050         if (eval != (unsigned long)eval)
2051                 return -EINVAL;
2052         str += len;
2053 
2054         if (*str != '\0')
2055                 return -EINVAL;
2056 
2057         *start = sval;
2058         *end = eval;
2059 
2060         return 0;
2061 }
2062 
2063 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
2064 {
2065         unsigned long vm_start, vm_end;
2066         bool exact_vma_exists = false;
2067         struct mm_struct *mm = NULL;
2068         struct task_struct *task;
2069         struct inode *inode;
2070         int status = 0;
2071 
2072         if (flags & LOOKUP_RCU)
2073                 return -ECHILD;
2074 
2075         inode = d_inode(dentry);
2076         task = get_proc_task(inode);
2077         if (!task)
2078                 goto out_notask;
2079 
2080         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
2081         if (IS_ERR_OR_NULL(mm))
2082                 goto out;
2083 
2084         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
2085                 status = down_read_killable(&mm->mmap_sem);
2086                 if (!status) {
2087                         exact_vma_exists = !!find_exact_vma(mm, vm_start,
2088                                                             vm_end);
2089                         up_read(&mm->mmap_sem);
2090                 }
2091         }
2092 
2093         mmput(mm);
2094 
2095         if (exact_vma_exists) {
2096                 task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
2097 
2098                 security_task_to_inode(task, inode);
2099                 status = 1;
2100         }
2101 
2102 out:
2103         put_task_struct(task);
2104 
2105 out_notask:
2106         return status;
2107 }
2108 
2109 static const struct dentry_operations tid_map_files_dentry_operations = {
2110         .d_revalidate   = map_files_d_revalidate,
2111         .d_delete       = pid_delete_dentry,
2112 };
2113 
2114 static int map_files_get_link(struct dentry *dentry, struct path *path)
2115 {
2116         unsigned long vm_start, vm_end;
2117         struct vm_area_struct *vma;
2118         struct task_struct *task;
2119         struct mm_struct *mm;
2120         int rc;
2121 
2122         rc = -ENOENT;
2123         task = get_proc_task(d_inode(dentry));
2124         if (!task)
2125                 goto out;
2126 
2127         mm = get_task_mm(task);
2128         put_task_struct(task);
2129         if (!mm)
2130                 goto out;
2131 
2132         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
2133         if (rc)
2134                 goto out_mmput;
2135 
2136         rc = down_read_killable(&mm->mmap_sem);
2137         if (rc)
2138                 goto out_mmput;
2139 
2140         rc = -ENOENT;
2141         vma = find_exact_vma(mm, vm_start, vm_end);
2142         if (vma && vma->vm_file) {
2143                 *path = vma->vm_file->f_path;
2144                 path_get(path);
2145                 rc = 0;
2146         }
2147         up_read(&mm->mmap_sem);
2148 
2149 out_mmput:
2150         mmput(mm);
2151 out:
2152         return rc;
2153 }
2154 
2155 struct map_files_info {
2156         unsigned long   start;
2157         unsigned long   end;
2158         fmode_t         mode;
2159 };
2160 
2161 /*
2162  * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
2163  * symlinks may be used to bypass permissions on ancestor directories in the
2164  * path to the file in question.
2165  */
2166 static const char *
2167 proc_map_files_get_link(struct dentry *dentry,
2168                         struct inode *inode,
2169                         struct delayed_call *done)
2170 {
2171         if (!capable(CAP_SYS_ADMIN))
2172                 return ERR_PTR(-EPERM);
2173 
2174         return proc_pid_get_link(dentry, inode, done);
2175 }
2176 
2177 /*
2178  * Identical to proc_pid_link_inode_operations except for get_link()
2179  */
2180 static const struct inode_operations proc_map_files_link_inode_operations = {
2181         .readlink       = proc_pid_readlink,
2182         .get_link       = proc_map_files_get_link,
2183         .setattr        = proc_setattr,
2184 };
2185 
2186 static struct dentry *
2187 proc_map_files_instantiate(struct dentry *dentry,
2188                            struct task_struct *task, const void *ptr)
2189 {
2190         fmode_t mode = (fmode_t)(unsigned long)ptr;
2191         struct proc_inode *ei;
2192         struct inode *inode;
2193 
2194         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
2195                                     ((mode & FMODE_READ ) ? S_IRUSR : 0) |
2196                                     ((mode & FMODE_WRITE) ? S_IWUSR : 0));
2197         if (!inode)
2198                 return ERR_PTR(-ENOENT);
2199 
2200         ei = PROC_I(inode);
2201         ei->op.proc_get_link = map_files_get_link;
2202 
2203         inode->i_op = &proc_map_files_link_inode_operations;
2204         inode->i_size = 64;
2205 
2206         d_set_d_op(dentry, &tid_map_files_dentry_operations);
2207         return d_splice_alias(inode, dentry);
2208 }
2209 
2210 static struct dentry *proc_map_files_lookup(struct inode *dir,
2211                 struct dentry *dentry, unsigned int flags)
2212 {
2213         unsigned long vm_start, vm_end;
2214         struct vm_area_struct *vma;
2215         struct task_struct *task;
2216         struct dentry *result;
2217         struct mm_struct *mm;
2218 
2219         result = ERR_PTR(-ENOENT);
2220         task = get_proc_task(dir);
2221         if (!task)
2222                 goto out;
2223 
2224         result = ERR_PTR(-EACCES);
2225         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2226                 goto out_put_task;
2227 
2228         result = ERR_PTR(-ENOENT);
2229         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
2230                 goto out_put_task;
2231 
2232         mm = get_task_mm(task);
2233         if (!mm)
2234                 goto out_put_task;
2235 
2236         result = ERR_PTR(-EINTR);
2237         if (down_read_killable(&mm->mmap_sem))
2238                 goto out_put_mm;
2239 
2240         result = ERR_PTR(-ENOENT);
2241         vma = find_exact_vma(mm, vm_start, vm_end);
2242         if (!vma)
2243                 goto out_no_vma;
2244 
2245         if (vma->vm_file)
2246                 result = proc_map_files_instantiate(dentry, task,
2247                                 (void *)(unsigned long)vma->vm_file->f_mode);
2248 
2249 out_no_vma:
2250         up_read(&mm->mmap_sem);
2251 out_put_mm:
2252         mmput(mm);
2253 out_put_task:
2254         put_task_struct(task);
2255 out:
2256         return result;
2257 }
2258 
2259 static const struct inode_operations proc_map_files_inode_operations = {
2260         .lookup         = proc_map_files_lookup,
2261         .permission     = proc_fd_permission,
2262         .setattr        = proc_setattr,
2263 };
2264 
2265 static int
2266 proc_map_files_readdir(struct file *file, struct dir_context *ctx)
2267 {
2268         struct vm_area_struct *vma;
2269         struct task_struct *task;
2270         struct mm_struct *mm;
2271         unsigned long nr_files, pos, i;
2272         GENRADIX(struct map_files_info) fa;
2273         struct map_files_info *p;
2274         int ret;
2275 
2276         genradix_init(&fa);
2277 
2278         ret = -ENOENT;
2279         task = get_proc_task(file_inode(file));
2280         if (!task)
2281                 goto out;
2282 
2283         ret = -EACCES;
2284         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
2285                 goto out_put_task;
2286 
2287         ret = 0;
2288         if (!dir_emit_dots(file, ctx))
2289                 goto out_put_task;
2290 
2291         mm = get_task_mm(task);
2292         if (!mm)
2293                 goto out_put_task;
2294 
2295         ret = down_read_killable(&mm->mmap_sem);
2296         if (ret) {
2297                 mmput(mm);
2298                 goto out_put_task;
2299         }
2300 
2301         nr_files = 0;
2302 
2303         /*
2304          * We need two passes here:
2305          *
2306          *  1) Collect vmas of mapped files with mmap_sem taken
2307          *  2) Release mmap_sem and instantiate entries
2308          *
2309          * otherwise we get lockdep complained, since filldir()
2310          * routine might require mmap_sem taken in might_fault().
2311          */
2312 
2313         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
2314                 if (!vma->vm_file)
2315                         continue;
2316                 if (++pos <= ctx->pos)
2317                         continue;
2318 
2319                 p = genradix_ptr_alloc(&fa, nr_files++, GFP_KERNEL);
2320                 if (!p) {
2321                         ret = -ENOMEM;
2322                         up_read(&mm->mmap_sem);
2323                         mmput(mm);
2324                         goto out_put_task;
2325                 }
2326 
2327                 p->start = vma->vm_start;
2328                 p->end = vma->vm_end;
2329                 p->mode = vma->vm_file->f_mode;
2330         }
2331         up_read(&mm->mmap_sem);
2332         mmput(mm);
2333 
2334         for (i = 0; i < nr_files; i++) {
2335                 char buf[4 * sizeof(long) + 2]; /* max: %lx-%lx\0 */
2336                 unsigned int len;
2337 
2338                 p = genradix_ptr(&fa, i);
2339                 len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
2340                 if (!proc_fill_cache(file, ctx,
2341                                       buf, len,
2342                                       proc_map_files_instantiate,
2343                                       task,
2344                                       (void *)(unsigned long)p->mode))
2345                         break;
2346                 ctx->pos++;
2347         }
2348 
2349 out_put_task:
2350         put_task_struct(task);
2351 out:
2352         genradix_free(&fa);
2353         return ret;
2354 }
2355 
2356 static const struct file_operations proc_map_files_operations = {
2357         .read           = generic_read_dir,
2358         .iterate_shared = proc_map_files_readdir,
2359         .llseek         = generic_file_llseek,
2360 };
2361 
2362 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
2363 struct timers_private {
2364         struct pid *pid;
2365         struct task_struct *task;
2366         struct sighand_struct *sighand;
2367         struct pid_namespace *ns;
2368         unsigned long flags;
2369 };
2370 
2371 static void *timers_start(struct seq_file *m, loff_t *pos)
2372 {
2373         struct timers_private *tp = m->private;
2374 
2375         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2376         if (!tp->task)
2377                 return ERR_PTR(-ESRCH);
2378 
2379         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2380         if (!tp->sighand)
2381                 return ERR_PTR(-ESRCH);
2382 
2383         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2384 }
2385 
2386 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2387 {
2388         struct timers_private *tp = m->private;
2389         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2390 }
2391 
2392 static void timers_stop(struct seq_file *m, void *v)
2393 {
2394         struct timers_private *tp = m->private;
2395 
2396         if (tp->sighand) {
2397                 unlock_task_sighand(tp->task, &tp->flags);
2398                 tp->sighand = NULL;
2399         }
2400 
2401         if (tp->task) {
2402                 put_task_struct(tp->task);
2403                 tp->task = NULL;
2404         }
2405 }
2406 
2407 static int show_timer(struct seq_file *m, void *v)
2408 {
2409         struct k_itimer *timer;
2410         struct timers_private *tp = m->private;
2411         int notify;
2412         static const char * const nstr[] = {
2413                 [SIGEV_SIGNAL] = "signal",
2414                 [SIGEV_NONE] = "none",
2415                 [SIGEV_THREAD] = "thread",
2416         };
2417 
2418         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2419         notify = timer->it_sigev_notify;
2420 
2421         seq_printf(m, "ID: %d\n", timer->it_id);
2422         seq_printf(m, "signal: %d/%px\n",
2423                    timer->sigq->info.si_signo,
2424                    timer->sigq->info.si_value.sival_ptr);
2425         seq_printf(m, "notify: %s/%s.%d\n",
2426                    nstr[notify & ~SIGEV_THREAD_ID],
2427                    (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2428                    pid_nr_ns(timer->it_pid, tp->ns));
2429         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2430 
2431         return 0;
2432 }
2433 
2434 static const struct seq_operations proc_timers_seq_ops = {
2435         .start  = timers_start,
2436         .next   = timers_next,
2437         .stop   = timers_stop,
2438         .show   = show_timer,
2439 };
2440 
2441 static int proc_timers_open(struct inode *inode, struct file *file)
2442 {
2443         struct timers_private *tp;
2444 
2445         tp = __seq_open_private(file, &proc_timers_seq_ops,
2446                         sizeof(struct timers_private));
2447         if (!tp)
2448                 return -ENOMEM;
2449 
2450         tp->pid = proc_pid(inode);
2451         tp->ns = proc_pid_ns(inode);
2452         return 0;
2453 }
2454 
2455 static const struct file_operations proc_timers_operations = {
2456         .open           = proc_timers_open,
2457         .read           = seq_read,
2458         .llseek         = seq_lseek,
2459         .release        = seq_release_private,
2460 };
2461 #endif
2462 
2463 static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
2464                                         size_t count, loff_t *offset)
2465 {
2466         struct inode *inode = file_inode(file);
2467         struct task_struct *p;
2468         u64 slack_ns;
2469         int err;
2470 
2471         err = kstrtoull_from_user(buf, count, 10, &slack_ns);
2472         if (err < 0)
2473                 return err;
2474 
2475         p = get_proc_task(inode);
2476         if (!p)
2477                 return -ESRCH;
2478 
2479         if (p != current) {
2480                 rcu_read_lock();
2481                 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2482                         rcu_read_unlock();
2483                         count = -EPERM;
2484                         goto out;
2485                 }
2486                 rcu_read_unlock();
2487 
2488                 err = security_task_setscheduler(p);
2489                 if (err) {
2490                         count = err;
2491                         goto out;
2492                 }
2493         }
2494 
2495         task_lock(p);
2496         if (slack_ns == 0)
2497                 p->timer_slack_ns = p->default_timer_slack_ns;
2498         else
2499                 p->timer_slack_ns = slack_ns;
2500         task_unlock(p);
2501 
2502 out:
2503         put_task_struct(p);
2504 
2505         return count;
2506 }
2507 
2508 static int timerslack_ns_show(struct seq_file *m, void *v)
2509 {
2510         struct inode *inode = m->private;
2511         struct task_struct *p;
2512         int err = 0;
2513 
2514         p = get_proc_task(inode);
2515         if (!p)
2516                 return -ESRCH;
2517 
2518         if (p != current) {
2519                 rcu_read_lock();
2520                 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
2521                         rcu_read_unlock();
2522                         err = -EPERM;
2523                         goto out;
2524                 }
2525                 rcu_read_unlock();
2526 
2527                 err = security_task_getscheduler(p);
2528                 if (err)
2529                         goto out;
2530         }
2531 
2532         task_lock(p);
2533         seq_printf(m, "%llu\n", p->timer_slack_ns);
2534         task_unlock(p);
2535 
2536 out:
2537         put_task_struct(p);
2538 
2539         return err;
2540 }
2541 
2542 static int timerslack_ns_open(struct inode *inode, struct file *filp)
2543 {
2544         return single_open(filp, timerslack_ns_show, inode);
2545 }
2546 
2547 static const struct file_operations proc_pid_set_timerslack_ns_operations = {
2548         .open           = timerslack_ns_open,
2549         .read           = seq_read,
2550         .write          = timerslack_ns_write,
2551         .llseek         = seq_lseek,
2552         .release        = single_release,
2553 };
2554 
2555 static struct dentry *proc_pident_instantiate(struct dentry *dentry,
2556         struct task_struct *task, const void *ptr)
2557 {
2558         const struct pid_entry *p = ptr;
2559         struct inode *inode;
2560         struct proc_inode *ei;
2561 
2562         inode = proc_pid_make_inode(dentry->d_sb, task, p->mode);
2563         if (!inode)
2564                 return ERR_PTR(-ENOENT);
2565 
2566         ei = PROC_I(inode);
2567         if (S_ISDIR(inode->i_mode))
2568                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2569         if (p->iop)
2570                 inode->i_op = p->iop;
2571         if (p->fop)
2572                 inode->i_fop = p->fop;
2573         ei->op = p->op;
2574         pid_update_inode(task, inode);
2575         d_set_d_op(dentry, &pid_dentry_operations);
2576         return d_splice_alias(inode, dentry);
2577 }
2578 
2579 static struct dentry *proc_pident_lookup(struct inode *dir, 
2580                                          struct dentry *dentry,
2581                                          const struct pid_entry *p,
2582                                          const struct pid_entry *end)
2583 {
2584         struct task_struct *task = get_proc_task(dir);
2585         struct dentry *res = ERR_PTR(-ENOENT);
2586 
2587         if (!task)
2588                 goto out_no_task;
2589 
2590         /*
2591          * Yes, it does not scale. And it should not. Don't add
2592          * new entries into /proc/<tgid>/ without very good reasons.
2593          */
2594         for (; p < end; p++) {
2595                 if (p->len != dentry->d_name.len)
2596                         continue;
2597                 if (!memcmp(dentry->d_name.name, p->name, p->len)) {
2598                         res = proc_pident_instantiate(dentry, task, p);
2599                         break;
2600                 }
2601         }
2602         put_task_struct(task);
2603 out_no_task:
2604         return res;
2605 }
2606 
2607 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
2608                 const struct pid_entry *ents, unsigned int nents)
2609 {
2610         struct task_struct *task = get_proc_task(file_inode(file));
2611         const struct pid_entry *p;
2612 
2613         if (!task)
2614                 return -ENOENT;
2615 
2616         if (!dir_emit_dots(file, ctx))
2617                 goto out;
2618 
2619         if (ctx->pos >= nents + 2)
2620                 goto out;
2621 
2622         for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
2623                 if (!proc_fill_cache(file, ctx, p->name, p->len,
2624                                 proc_pident_instantiate, task, p))
2625                         break;
2626                 ctx->pos++;
2627         }
2628 out:
2629         put_task_struct(task);
2630         return 0;
2631 }
2632 
2633 #ifdef CONFIG_SECURITY
2634 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2635                                   size_t count, loff_t *ppos)
2636 {
2637         struct inode * inode = file_inode(file);
2638         char *p = NULL;
2639         ssize_t length;
2640         struct task_struct *task = get_proc_task(inode);
2641 
2642         if (!task)
2643                 return -ESRCH;
2644 
2645         length = security_getprocattr(task, PROC_I(inode)->op.lsm,
2646                                       (char*)file->f_path.dentry->d_name.name,
2647                                       &p);
2648         put_task_struct(task);
2649         if (length > 0)
2650                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2651         kfree(p);
2652         return length;
2653 }
2654 
2655 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2656                                    size_t count, loff_t *ppos)
2657 {
2658         struct inode * inode = file_inode(file);
2659         struct task_struct *task;
2660         void *page;
2661         int rv;
2662 
2663         rcu_read_lock();
2664         task = pid_task(proc_pid(inode), PIDTYPE_PID);
2665         if (!task) {
2666                 rcu_read_unlock();
2667                 return -ESRCH;
2668         }
2669         /* A task may only write its own attributes. */
2670         if (current != task) {
2671                 rcu_read_unlock();
2672                 return -EACCES;
2673         }
2674         /* Prevent changes to overridden credentials. */
2675         if (current_cred() != current_real_cred()) {
2676                 rcu_read_unlock();
2677                 return -EBUSY;
2678         }
2679         rcu_read_unlock();
2680 
2681         if (count > PAGE_SIZE)
2682                 count = PAGE_SIZE;
2683 
2684         /* No partial writes. */
2685         if (*ppos != 0)
2686                 return -EINVAL;
2687 
2688         page = memdup_user(buf, count);
2689         if (IS_ERR(page)) {
2690                 rv = PTR_ERR(page);
2691                 goto out;
2692         }
2693 
2694         /* Guard against adverse ptrace interaction */
2695         rv = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
2696         if (rv < 0)
2697                 goto out_free;
2698 
2699         rv = security_setprocattr(PROC_I(inode)->op.lsm,
2700                                   file->f_path.dentry->d_name.name, page,
2701                                   count);
2702         mutex_unlock(&current->signal->cred_guard_mutex);
2703 out_free:
2704         kfree(page);
2705 out:
2706         return rv;
2707 }
2708 
2709 static const struct file_operations proc_pid_attr_operations = {
2710         .read           = proc_pid_attr_read,
2711         .write          = proc_pid_attr_write,
2712         .llseek         = generic_file_llseek,
2713 };
2714 
2715 #define LSM_DIR_OPS(LSM) \
2716 static int proc_##LSM##_attr_dir_iterate(struct file *filp, \
2717                              struct dir_context *ctx) \
2718 { \
2719         return proc_pident_readdir(filp, ctx, \
2720                                    LSM##_attr_dir_stuff, \
2721                                    ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2722 } \
2723 \
2724 static const struct file_operations proc_##LSM##_attr_dir_ops = { \
2725         .read           = generic_read_dir, \
2726         .iterate        = proc_##LSM##_attr_dir_iterate, \
2727         .llseek         = default_llseek, \
2728 }; \
2729 \
2730 static struct dentry *proc_##LSM##_attr_dir_lookup(struct inode *dir, \
2731                                 struct dentry *dentry, unsigned int flags) \
2732 { \
2733         return proc_pident_lookup(dir, dentry, \
2734                                   LSM##_attr_dir_stuff, \
2735                                   LSM##_attr_dir_stuff + ARRAY_SIZE(LSM##_attr_dir_stuff)); \
2736 } \
2737 \
2738 static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \
2739         .lookup         = proc_##LSM##_attr_dir_lookup, \
2740         .getattr        = pid_getattr, \
2741         .setattr        = proc_setattr, \
2742 }
2743 
2744 #ifdef CONFIG_SECURITY_SMACK
2745 static const struct pid_entry smack_attr_dir_stuff[] = {
2746         ATTR("smack", "current",        0666),
2747 };
2748 LSM_DIR_OPS(smack);
2749 #endif
2750 
2751 static const struct pid_entry attr_dir_stuff[] = {
2752         ATTR(NULL, "current",           0666),
2753         ATTR(NULL, "prev",              0444),
2754         ATTR(NULL, "exec",              0666),
2755         ATTR(NULL, "fscreate",          0666),
2756         ATTR(NULL, "keycreate",         0666),
2757         ATTR(NULL, "sockcreate",        0666),
2758 #ifdef CONFIG_SECURITY_SMACK
2759         DIR("smack",                    0555,
2760             proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
2761 #endif
2762 };
2763 
2764 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
2765 {
2766         return proc_pident_readdir(file, ctx, 
2767                                    attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2768 }
2769 
2770 static const struct file_operations proc_attr_dir_operations = {
2771         .read           = generic_read_dir,
2772         .iterate_shared = proc_attr_dir_readdir,
2773         .llseek         = generic_file_llseek,
2774 };
2775 
2776 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2777                                 struct dentry *dentry, unsigned int flags)
2778 {
2779         return proc_pident_lookup(dir, dentry,
2780                                   attr_dir_stuff,
2781                                   attr_dir_stuff + ARRAY_SIZE(attr_dir_stuff));
2782 }
2783 
2784 static const struct inode_operations proc_attr_dir_inode_operations = {
2785         .lookup         = proc_attr_dir_lookup,
2786         .getattr        = pid_getattr,
2787         .setattr        = proc_setattr,
2788 };
2789 
2790 #endif
2791 
2792 #ifdef CONFIG_ELF_CORE
2793 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2794                                          size_t count, loff_t *ppos)
2795 {
2796         struct task_struct *task = get_proc_task(file_inode(file));
2797         struct mm_struct *mm;
2798         char buffer[PROC_NUMBUF];
2799         size_t len;
2800         int ret;
2801 
2802         if (!task)
2803                 return -ESRCH;
2804 
2805         ret = 0;
2806         mm = get_task_mm(task);
2807         if (mm) {
2808                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2809                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2810                                 MMF_DUMP_FILTER_SHIFT));
2811                 mmput(mm);
2812                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2813         }
2814 
2815         put_task_struct(task);
2816 
2817         return ret;
2818 }
2819 
2820 static ssize_t proc_coredump_filter_write(struct file *file,
2821                                           const char __user *buf,
2822                                           size_t count,
2823                                           loff_t *ppos)
2824 {
2825         struct task_struct *task;
2826         struct mm_struct *mm;
2827         unsigned int val;
2828         int ret;
2829         int i;
2830         unsigned long mask;
2831 
2832         ret = kstrtouint_from_user(buf, count, 0, &val);
2833         if (ret < 0)
2834                 return ret;
2835 
2836         ret = -ESRCH;
2837         task = get_proc_task(file_inode(file));
2838         if (!task)
2839                 goto out_no_task;
2840 
2841         mm = get_task_mm(task);
2842         if (!mm)
2843                 goto out_no_mm;
2844         ret = 0;
2845 
2846         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2847                 if (val & mask)
2848                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2849                 else
2850                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2851         }
2852 
2853         mmput(mm);
2854  out_no_mm:
2855         put_task_struct(task);
2856  out_no_task:
2857         if (ret < 0)
2858                 return ret;
2859         return count;
2860 }
2861 
2862 static const struct file_operations proc_coredump_filter_operations = {
2863         .read           = proc_coredump_filter_read,
2864         .write          = proc_coredump_filter_write,
2865         .llseek         = generic_file_llseek,
2866 };
2867 #endif
2868 
2869 #ifdef CONFIG_TASK_IO_ACCOUNTING
2870 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
2871 {
2872         struct task_io_accounting acct = task->ioac;
2873         unsigned long flags;
2874         int result;
2875 
2876         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2877         if (result)
2878                 return result;
2879 
2880         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
2881                 result = -EACCES;
2882                 goto out_unlock;
2883         }
2884 
2885         if (whole && lock_task_sighand(task, &flags)) {
2886                 struct task_struct *t = task;
2887 
2888                 task_io_accounting_add(&acct, &task->signal->ioac);
2889                 while_each_thread(task, t)
2890                         task_io_accounting_add(&acct, &t->ioac);
2891 
2892                 unlock_task_sighand(task, &flags);
2893         }
2894         seq_printf(m,
2895                    "rchar: %llu\n"
2896                    "wchar: %llu\n"
2897                    "syscr: %llu\n"
2898                    "syscw: %llu\n"
2899                    "read_bytes: %llu\n"
2900                    "write_bytes: %llu\n"
2901                    "cancelled_write_bytes: %llu\n",
2902                    (unsigned long long)acct.rchar,
2903                    (unsigned long long)acct.wchar,
2904                    (unsigned long long)acct.syscr,
2905                    (unsigned long long)acct.syscw,
2906                    (unsigned long long)acct.read_bytes,
2907                    (unsigned long long)acct.write_bytes,
2908                    (unsigned long long)acct.cancelled_write_bytes);
2909         result = 0;
2910 
2911 out_unlock:
2912         mutex_unlock(&task->signal->cred_guard_mutex);
2913         return result;
2914 }
2915 
2916 static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2917                                   struct pid *pid, struct task_struct *task)
2918 {
2919         return do_io_accounting(task, m, 0);
2920 }
2921 
2922 static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
2923                                    struct pid *pid, struct task_struct *task)
2924 {
2925         return do_io_accounting(task, m, 1);
2926 }
2927 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2928 
2929 #ifdef CONFIG_USER_NS
2930 static int proc_id_map_open(struct inode *inode, struct file *file,
2931         const struct seq_operations *seq_ops)
2932 {
2933         struct user_namespace *ns = NULL;
2934         struct task_struct *task;
2935         struct seq_file *seq;
2936         int ret = -EINVAL;
2937 
2938         task = get_proc_task(inode);
2939         if (task) {
2940                 rcu_read_lock();
2941                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2942                 rcu_read_unlock();
2943                 put_task_struct(task);
2944         }
2945         if (!ns)
2946                 goto err;
2947 
2948         ret = seq_open(file, seq_ops);
2949         if (ret)
2950                 goto err_put_ns;
2951 
2952         seq = file->private_data;
2953         seq->private = ns;
2954 
2955         return 0;
2956 err_put_ns:
2957         put_user_ns(ns);
2958 err:
2959         return ret;
2960 }
2961 
2962 static int proc_id_map_release(struct inode *inode, struct file *file)
2963 {
2964         struct seq_file *seq = file->private_data;
2965         struct user_namespace *ns = seq->private;
2966         put_user_ns(ns);
2967         return seq_release(inode, file);
2968 }
2969 
2970 static int proc_uid_map_open(struct inode *inode, struct file *file)
2971 {
2972         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2973 }
2974 
2975 static int proc_gid_map_open(struct inode *inode, struct file *file)
2976 {
2977         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2978 }
2979 
2980 static int proc_projid_map_open(struct inode *inode, struct file *file)
2981 {
2982         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2983 }
2984 
2985 static const struct file_operations proc_uid_map_operations = {
2986         .open           = proc_uid_map_open,
2987         .write          = proc_uid_map_write,
2988         .read           = seq_read,
2989         .llseek         = seq_lseek,
2990         .release        = proc_id_map_release,
2991 };
2992 
2993 static const struct file_operations proc_gid_map_operations = {
2994         .open           = proc_gid_map_open,
2995         .write          = proc_gid_map_write,
2996         .read           = seq_read,
2997         .llseek         = seq_lseek,
2998         .release        = proc_id_map_release,
2999 };
3000 
3001 static const struct file_operations proc_projid_map_operations = {
3002         .open           = proc_projid_map_open,
3003         .write          = proc_projid_map_write,
3004         .read           = seq_read,
3005         .llseek         = seq_lseek,
3006         .release        = proc_id_map_release,
3007 };
3008 
3009 static int proc_setgroups_open(struct inode *inode, struct file *file)
3010 {
3011         struct user_namespace *ns = NULL;
3012         struct task_struct *task;
3013         int ret;
3014 
3015         ret = -ESRCH;
3016         task = get_proc_task(inode);
3017         if (task) {
3018                 rcu_read_lock();
3019                 ns = get_user_ns(task_cred_xxx(task, user_ns));
3020                 rcu_read_unlock();
3021                 put_task_struct(task);
3022         }
3023         if (!ns)
3024                 goto err;
3025 
3026         if (file->f_mode & FMODE_WRITE) {
3027                 ret = -EACCES;
3028                 if (!ns_capable(ns, CAP_SYS_ADMIN))
3029                         goto err_put_ns;
3030         }
3031 
3032         ret = single_open(file, &proc_setgroups_show, ns);
3033         if (ret)
3034                 goto err_put_ns;
3035 
3036         return 0;
3037 err_put_ns:
3038         put_user_ns(ns);
3039 err:
3040         return ret;
3041 }
3042 
3043 static int proc_setgroups_release(struct inode *inode, struct file *file)
3044 {
3045         struct seq_file *seq = file->private_data;
3046         struct user_namespace *ns = seq->private;
3047         int ret = single_release(inode, file);
3048         put_user_ns(ns);
3049         return ret;
3050 }
3051 
3052 static const struct file_operations proc_setgroups_operations = {
3053         .open           = proc_setgroups_open,
3054         .write          = proc_setgroups_write,
3055         .read           = seq_read,
3056         .llseek         = seq_lseek,
3057         .release        = proc_setgroups_release,
3058 };
3059 #endif /* CONFIG_USER_NS */
3060 
3061 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
3062                                 struct pid *pid, struct task_struct *task)
3063 {
3064         int err = lock_trace(task);
3065         if (!err) {
3066                 seq_printf(m, "%08x\n", task->personality);
3067                 unlock_trace(task);
3068         }
3069         return err;
3070 }
3071 
3072 #ifdef CONFIG_LIVEPATCH
3073 static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns,
3074                                 struct pid *pid, struct task_struct *task)
3075 {
3076         seq_printf(m, "%d\n", task->patch_state);
3077         return 0;
3078 }
3079 #endif /* CONFIG_LIVEPATCH */
3080 
3081 #ifdef CONFIG_STACKLEAK_METRICS
3082 static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns,
3083                                 struct pid *pid, struct task_struct *task)
3084 {
3085         unsigned long prev_depth = THREAD_SIZE -
3086                                 (task->prev_lowest_stack & (THREAD_SIZE - 1));
3087         unsigned long depth = THREAD_SIZE -
3088                                 (task->lowest_stack & (THREAD_SIZE - 1));
3089 
3090         seq_printf(m, "previous stack depth: %lu\nstack depth: %lu\n",
3091                                                         prev_depth, depth);
3092         return 0;
3093 }
3094 #endif /* CONFIG_STACKLEAK_METRICS */
3095 
3096 /*
3097  * Thread groups
3098  */
3099 static const struct file_operations proc_task_operations;
3100 static const struct inode_operations proc_task_inode_operations;
3101 
3102 static const struct pid_entry tgid_base_stuff[] = {
3103         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
3104         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3105         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
3106         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3107         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3108 #ifdef CONFIG_NET
3109         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3110 #endif
3111         REG("environ",    S_IRUSR, proc_environ_operations),
3112         REG("auxv",       S_IRUSR, proc_auxv_operations),
3113         ONE("status",     S_IRUGO, proc_pid_status),
3114         ONE("personality", S_IRUSR, proc_pid_personality),
3115         ONE("limits",     S_IRUGO, proc_pid_limits),
3116 #ifdef CONFIG_SCHED_DEBUG
3117         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3118 #endif
3119 #ifdef CONFIG_SCHED_AUTOGROUP
3120         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
3121 #endif
3122 #ifdef CONFIG_TIME_NS
3123         REG("timens_offsets",  S_IRUGO|S_IWUSR, proc_timens_offsets_operations),
3124 #endif
3125         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3126 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3127         ONE("syscall",    S_IRUSR, proc_pid_syscall),
3128 #endif
3129         REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
3130         ONE("stat",       S_IRUGO, proc_tgid_stat),
3131         ONE("statm",      S_IRUGO, proc_pid_statm),
3132         REG("maps",       S_IRUGO, proc_pid_maps_operations),
3133 #ifdef CONFIG_NUMA
3134         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
3135 #endif
3136         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
3137         LNK("cwd",        proc_cwd_link),
3138         LNK("root",       proc_root_link),
3139         LNK("exe",        proc_exe_link),
3140         REG("mounts",     S_IRUGO, proc_mounts_operations),
3141         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3142         REG("mountstats", S_IRUSR, proc_mountstats_operations),
3143 #ifdef CONFIG_PROC_PAGE_MONITOR
3144         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3145         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
3146         REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3147         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3148 #endif
3149 #ifdef CONFIG_SECURITY
3150         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3151 #endif
3152 #ifdef CONFIG_KALLSYMS
3153         ONE("wchan",      S_IRUGO, proc_pid_wchan),
3154 #endif
3155 #ifdef CONFIG_STACKTRACE
3156         ONE("stack",      S_IRUSR, proc_pid_stack),
3157 #endif
3158 #ifdef CONFIG_SCHED_INFO
3159         ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
3160 #endif
3161 #ifdef CONFIG_LATENCYTOP
3162         REG("latency",  S_IRUGO, proc_lstats_operations),
3163 #endif
3164 #ifdef CONFIG_PROC_PID_CPUSET
3165         ONE("cpuset",     S_IRUGO, proc_cpuset_show),
3166 #endif
3167 #ifdef CONFIG_CGROUPS
3168         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3169 #endif
3170 #ifdef CONFIG_PROC_CPU_RESCTRL
3171         ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3172 #endif
3173         ONE("oom_score",  S_IRUGO, proc_oom_score),
3174         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3175         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3176 #ifdef CONFIG_AUDIT
3177         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
3178         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3179 #endif
3180 #ifdef CONFIG_FAULT_INJECTION
3181         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3182         REG("fail-nth", 0644, proc_fail_nth_operations),
3183 #endif
3184 #ifdef CONFIG_ELF_CORE
3185         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
3186 #endif
3187 #ifdef CONFIG_TASK_IO_ACCOUNTING
3188         ONE("io",       S_IRUSR, proc_tgid_io_accounting),
3189 #endif
3190 #ifdef CONFIG_USER_NS
3191         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3192         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3193         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3194         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3195 #endif
3196 #if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
3197         REG("timers",     S_IRUGO, proc_timers_operations),
3198 #endif
3199         REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
3200 #ifdef CONFIG_LIVEPATCH
3201         ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3202 #endif
3203 #ifdef CONFIG_STACKLEAK_METRICS
3204         ONE("stack_depth", S_IRUGO, proc_stack_depth),
3205 #endif
3206 #ifdef CONFIG_PROC_PID_ARCH_STATUS
3207         ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3208 #endif
3209 };
3210 
3211 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
3212 {
3213         return proc_pident_readdir(file, ctx,
3214                                    tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3215 }
3216 
3217 static const struct file_operations proc_tgid_base_operations = {
3218         .read           = generic_read_dir,
3219         .iterate_shared = proc_tgid_base_readdir,
3220         .llseek         = generic_file_llseek,
3221 };
3222 
3223 struct pid *tgid_pidfd_to_pid(const struct file *file)
3224 {
3225         if (file->f_op != &proc_tgid_base_operations)
3226                 return ERR_PTR(-EBADF);
3227 
3228         return proc_pid(file_inode(file));
3229 }
3230 
3231 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3232 {
3233         return proc_pident_lookup(dir, dentry,
3234                                   tgid_base_stuff,
3235                                   tgid_base_stuff + ARRAY_SIZE(tgid_base_stuff));
3236 }
3237 
3238 static const struct inode_operations proc_tgid_base_inode_operations = {
3239         .lookup         = proc_tgid_base_lookup,
3240         .getattr        = pid_getattr,
3241         .setattr        = proc_setattr,
3242         .permission     = proc_pid_permission,
3243 };
3244 
3245 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
3246 {
3247         struct dentry *dentry, *leader, *dir;
3248         char buf[10 + 1];
3249         struct qstr name;
3250 
3251         name.name = buf;
3252         name.len = snprintf(buf, sizeof(buf), "%u", pid);
3253         /* no ->d_hash() rejects on procfs */
3254         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
3255         if (dentry) {
3256                 d_invalidate(dentry);
3257                 dput(dentry);
3258         }
3259 
3260         if (pid == tgid)
3261                 return;
3262 
3263         name.name = buf;
3264         name.len = snprintf(buf, sizeof(buf), "%u", tgid);
3265         leader = d_hash_and_lookup(mnt->mnt_root, &name);
3266         if (!leader)
3267                 goto out;
3268 
3269         name.name = "task";
3270         name.len = strlen(name.name);
3271         dir = d_hash_and_lookup(leader, &name);
3272         if (!dir)
3273                 goto out_put_leader;
3274 
3275         name.name = buf;
3276         name.len = snprintf(buf, sizeof(buf), "%u", pid);
3277         dentry = d_hash_and_lookup(dir, &name);
3278         if (dentry) {
3279                 d_invalidate(dentry);
3280                 dput(dentry);
3281         }
3282 
3283         dput(dir);
3284 out_put_leader:
3285         dput(leader);
3286 out:
3287         return;
3288 }
3289 
3290 /**
3291  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
3292  * @task: task that should be flushed.
3293  *
3294  * When flushing dentries from proc, one needs to flush them from global
3295  * proc (proc_mnt) and from all the namespaces' procs this task was seen
3296  * in. This call is supposed to do all of this job.
3297  *
3298  * Looks in the dcache for
3299  * /proc/@pid
3300  * /proc/@tgid/task/@pid
3301  * if either directory is present flushes it and all of it'ts children
3302  * from the dcache.
3303  *
3304  * It is safe and reasonable to cache /proc entries for a task until
3305  * that task exits.  After that they just clog up the dcache with
3306  * useless entries, possibly causing useful dcache entries to be
3307  * flushed instead.  This routine is proved to flush those useless
3308  * dcache entries at process exit time.
3309  *
3310  * NOTE: This routine is just an optimization so it does not guarantee
3311  *       that no dcache entries will exist at process exit time it
3312  *       just makes it very unlikely that any will persist.
3313  */
3314 
3315 void proc_flush_task(struct task_struct *task)
3316 {
3317         int i;
3318         struct pid *pid, *tgid;
3319         struct upid *upid;
3320 
3321         pid = task_pid(task);
3322         tgid = task_tgid(task);
3323 
3324         for (i = 0; i <= pid->level; i++) {
3325                 upid = &pid->numbers[i];
3326                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
3327                                         tgid->numbers[i].nr);
3328         }
3329 }
3330 
3331 static struct dentry *proc_pid_instantiate(struct dentry * dentry,
3332                                    struct task_struct *task, const void *ptr)
3333 {
3334         struct inode *inode;
3335 
3336         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3337         if (!inode)
3338                 return ERR_PTR(-ENOENT);
3339 
3340         inode->i_op = &proc_tgid_base_inode_operations;
3341         inode->i_fop = &proc_tgid_base_operations;
3342         inode->i_flags|=S_IMMUTABLE;
3343 
3344         set_nlink(inode, nlink_tgid);
3345         pid_update_inode(task, inode);
3346 
3347         d_set_d_op(dentry, &pid_dentry_operations);
3348         return d_splice_alias(inode, dentry);
3349 }
3350 
3351 struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags)
3352 {
3353         struct task_struct *task;
3354         unsigned tgid;
3355         struct pid_namespace *ns;
3356         struct dentry *result = ERR_PTR(-ENOENT);
3357 
3358         tgid = name_to_int(&dentry->d_name);
3359         if (tgid == ~0U)
3360                 goto out;
3361 
3362         ns = dentry->d_sb->s_fs_info;
3363         rcu_read_lock();
3364         task = find_task_by_pid_ns(tgid, ns);
3365         if (task)
3366                 get_task_struct(task);
3367         rcu_read_unlock();
3368         if (!task)
3369                 goto out;
3370 
3371         result = proc_pid_instantiate(dentry, task, NULL);
3372         put_task_struct(task);
3373 out:
3374         return result;
3375 }
3376 
3377 /*
3378  * Find the first task with tgid >= tgid
3379  *
3380  */
3381 struct tgid_iter {
3382         unsigned int tgid;
3383         struct task_struct *task;
3384 };
3385 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3386 {
3387         struct pid *pid;
3388 
3389         if (iter.task)
3390                 put_task_struct(iter.task);
3391         rcu_read_lock();
3392 retry:
3393         iter.task = NULL;
3394         pid = find_ge_pid(iter.tgid, ns);
3395         if (pid) {
3396                 iter.tgid = pid_nr_ns(pid, ns);
3397                 iter.task = pid_task(pid, PIDTYPE_PID);
3398                 /* What we to know is if the pid we have find is the
3399                  * pid of a thread_group_leader.  Testing for task
3400                  * being a thread_group_leader is the obvious thing
3401                  * todo but there is a window when it fails, due to
3402                  * the pid transfer logic in de_thread.
3403                  *
3404                  * So we perform the straight forward test of seeing
3405                  * if the pid we have found is the pid of a thread
3406                  * group leader, and don't worry if the task we have
3407                  * found doesn't happen to be a thread group leader.
3408                  * As we don't care in the case of readdir.
3409                  */
3410                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3411                         iter.tgid += 1;
3412                         goto retry;
3413                 }
3414                 get_task_struct(iter.task);
3415         }
3416         rcu_read_unlock();
3417         return iter;
3418 }
3419 
3420 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
3421 
3422 /* for the /proc/ directory itself, after non-process stuff has been done */
3423 int proc_pid_readdir(struct file *file, struct dir_context *ctx)
3424 {
3425         struct tgid_iter iter;
3426         struct pid_namespace *ns = proc_pid_ns(file_inode(file));
3427         loff_t pos = ctx->pos;
3428 
3429         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
3430                 return 0;
3431 
3432         if (pos == TGID_OFFSET - 2) {
3433                 struct inode *inode = d_inode(ns->proc_self);
3434                 if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
3435                         return 0;
3436                 ctx->pos = pos = pos + 1;
3437         }
3438         if (pos == TGID_OFFSET - 1) {
3439                 struct inode *inode = d_inode(ns->proc_thread_self);
3440                 if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
3441                         return 0;
3442                 ctx->pos = pos = pos + 1;
3443         }
3444         iter.tgid = pos - TGID_OFFSET;
3445         iter.task = NULL;
3446         for (iter = next_tgid(ns, iter);
3447              iter.task;
3448              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3449                 char name[10 + 1];
3450                 unsigned int len;
3451 
3452                 cond_resched();
3453                 if (!has_pid_permissions(ns, iter.task, HIDEPID_INVISIBLE))
3454                         continue;
3455 
3456                 len = snprintf(name, sizeof(name), "%u", iter.tgid);
3457                 ctx->pos = iter.tgid + TGID_OFFSET;
3458                 if (!proc_fill_cache(file, ctx, name, len,
3459                                      proc_pid_instantiate, iter.task, NULL)) {
3460                         put_task_struct(iter.task);
3461                         return 0;
3462                 }
3463         }
3464         ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
3465         return 0;
3466 }
3467 
3468 /*
3469  * proc_tid_comm_permission is a special permission function exclusively
3470  * used for the node /proc/<pid>/task/<tid>/comm.
3471  * It bypasses generic permission checks in the case where a task of the same
3472  * task group attempts to access the node.
3473  * The rationale behind this is that glibc and bionic access this node for
3474  * cross thread naming (pthread_set/getname_np(!self)). However, if
3475  * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
3476  * which locks out the cross thread naming implementation.
3477  * This function makes sure that the node is always accessible for members of
3478  * same thread group.
3479  */
3480 static int proc_tid_comm_permission(struct inode *inode, int mask)
3481 {
3482         bool is_same_tgroup;
3483         struct task_struct *task;
3484 
3485         task = get_proc_task(inode);
3486         if (!task)
3487                 return -ESRCH;
3488         is_same_tgroup = same_thread_group(current, task);
3489         put_task_struct(task);
3490 
3491         if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
3492                 /* This file (/proc/<pid>/task/<tid>/comm) can always be
3493                  * read or written by the members of the corresponding
3494                  * thread group.
3495                  */
3496                 return 0;
3497         }
3498 
3499         return generic_permission(inode, mask);
3500 }
3501 
3502 static const struct inode_operations proc_tid_comm_inode_operations = {
3503                 .permission = proc_tid_comm_permission,
3504 };
3505 
3506 /*
3507  * Tasks
3508  */
3509 static const struct pid_entry tid_base_stuff[] = {
3510         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3511         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3512         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3513 #ifdef CONFIG_NET
3514         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
3515 #endif
3516         REG("environ",   S_IRUSR, proc_environ_operations),
3517         REG("auxv",      S_IRUSR, proc_auxv_operations),
3518         ONE("status",    S_IRUGO, proc_pid_status),
3519         ONE("personality", S_IRUSR, proc_pid_personality),
3520         ONE("limits",    S_IRUGO, proc_pid_limits),
3521 #ifdef CONFIG_SCHED_DEBUG
3522         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3523 #endif
3524         NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
3525                          &proc_tid_comm_inode_operations,
3526                          &proc_pid_set_comm_operations, {}),
3527 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3528         ONE("syscall",   S_IRUSR, proc_pid_syscall),
3529 #endif
3530         REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
3531         ONE("stat",      S_IRUGO, proc_tid_stat),
3532         ONE("statm",     S_IRUGO, proc_pid_statm),
3533         REG("maps",      S_IRUGO, proc_pid_maps_operations),
3534 #ifdef CONFIG_PROC_CHILDREN
3535         REG("children",  S_IRUGO, proc_tid_children_operations),
3536 #endif
3537 #ifdef CONFIG_NUMA
3538         REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations),
3539 #endif
3540         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3541         LNK("cwd",       proc_cwd_link),
3542         LNK("root",      proc_root_link),
3543         LNK("exe",       proc_exe_link),
3544         REG("mounts",    S_IRUGO, proc_mounts_operations),
3545         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3546 #ifdef CONFIG_PROC_PAGE_MONITOR
3547         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3548         REG("smaps",     S_IRUGO, proc_pid_smaps_operations),
3549         REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
3550         REG("pagemap",    S_IRUSR, proc_pagemap_operations),
3551 #endif
3552 #ifdef CONFIG_SECURITY
3553         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3554 #endif
3555 #ifdef CONFIG_KALLSYMS
3556         ONE("wchan",     S_IRUGO, proc_pid_wchan),
3557 #endif
3558 #ifdef CONFIG_STACKTRACE
3559         ONE("stack",      S_IRUSR, proc_pid_stack),
3560 #endif
3561 #ifdef CONFIG_SCHED_INFO
3562         ONE("schedstat", S_IRUGO, proc_pid_schedstat),
3563 #endif
3564 #ifdef CONFIG_LATENCYTOP
3565         REG("latency",  S_IRUGO, proc_lstats_operations),
3566 #endif
3567 #ifdef CONFIG_PROC_PID_CPUSET
3568         ONE("cpuset",    S_IRUGO, proc_cpuset_show),
3569 #endif
3570 #ifdef CONFIG_CGROUPS
3571         ONE("cgroup",  S_IRUGO, proc_cgroup_show),
3572 #endif
3573 #ifdef CONFIG_PROC_CPU_RESCTRL
3574         ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
3575 #endif
3576         ONE("oom_score", S_IRUGO, proc_oom_score),
3577         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3578         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3579 #ifdef CONFIG_AUDIT
3580         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3581         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3582 #endif
3583 #ifdef CONFIG_FAULT_INJECTION
3584         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3585         REG("fail-nth", 0644, proc_fail_nth_operations),
3586 #endif
3587 #ifdef CONFIG_TASK_IO_ACCOUNTING
3588         ONE("io",       S_IRUSR, proc_tid_io_accounting),
3589 #endif
3590 #ifdef CONFIG_USER_NS
3591         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3592         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3593         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3594         REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
3595 #endif
3596 #ifdef CONFIG_LIVEPATCH
3597         ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
3598 #endif
3599 #ifdef CONFIG_PROC_PID_ARCH_STATUS
3600         ONE("arch_status", S_IRUGO, proc_pid_arch_status),
3601 #endif
3602 };
3603 
3604 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
3605 {
3606         return proc_pident_readdir(file, ctx,
3607                                    tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3608 }
3609 
3610 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3611 {
3612         return proc_pident_lookup(dir, dentry,
3613                                   tid_base_stuff,
3614                                   tid_base_stuff + ARRAY_SIZE(tid_base_stuff));
3615 }
3616 
3617 static const struct file_operations proc_tid_base_operations = {
3618         .read           = generic_read_dir,
3619         .iterate_shared = proc_tid_base_readdir,
3620         .llseek         = generic_file_llseek,
3621 };
3622 
3623 static const struct inode_operations proc_tid_base_inode_operations = {
3624         .lookup         = proc_tid_base_lookup,
3625         .getattr        = pid_getattr,
3626         .setattr        = proc_setattr,
3627 };
3628 
3629 static struct dentry *proc_task_instantiate(struct dentry *dentry,
3630         struct task_struct *task, const void *ptr)
3631 {
3632         struct inode *inode;
3633         inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
3634         if (!inode)
3635                 return ERR_PTR(-ENOENT);
3636 
3637         inode->i_op = &proc_tid_base_inode_operations;
3638         inode->i_fop = &proc_tid_base_operations;
3639         inode->i_flags |= S_IMMUTABLE;
3640 
3641         set_nlink(inode, nlink_tid);
3642         pid_update_inode(task, inode);
3643 
3644         d_set_d_op(dentry, &pid_dentry_operations);
3645         return d_splice_alias(inode, dentry);
3646 }
3647 
3648 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3649 {
3650         struct task_struct *task;
3651         struct task_struct *leader = get_proc_task(dir);
3652         unsigned tid;
3653         struct pid_namespace *ns;
3654         struct dentry *result = ERR_PTR(-ENOENT);
3655 
3656         if (!leader)
3657                 goto out_no_task;
3658 
3659         tid = name_to_int(&dentry->d_name);
3660         if (tid == ~0U)
3661                 goto out;
3662 
3663         ns = dentry->d_sb->s_fs_info;
3664         rcu_read_lock();
3665         task = find_task_by_pid_ns(tid, ns);
3666         if (task)
3667                 get_task_struct(task);
3668         rcu_read_unlock();
3669         if (!task)
3670                 goto out;
3671         if (!same_thread_group(leader, task))
3672                 goto out_drop_task;
3673 
3674         result = proc_task_instantiate(dentry, task, NULL);
3675 out_drop_task:
3676         put_task_struct(task);
3677 out:
3678         put_task_struct(leader);
3679 out_no_task:
3680         return result;
3681 }
3682 
3683 /*
3684  * Find the first tid of a thread group to return to user space.
3685  *
3686  * Usually this is just the thread group leader, but if the users
3687  * buffer was too small or there was a seek into the middle of the
3688  * directory we have more work todo.
3689  *
3690  * In the case of a short read we start with find_task_by_pid.
3691  *
3692  * In the case of a seek we start with the leader and walk nr
3693  * threads past it.
3694  */
3695 static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
3696                                         struct pid_namespace *ns)
3697 {
3698         struct task_struct *pos, *task;
3699         unsigned long nr = f_pos;
3700 
3701         if (nr != f_pos)        /* 32bit overflow? */
3702                 return NULL;
3703 
3704         rcu_read_lock();
3705         task = pid_task(pid, PIDTYPE_PID);
3706         if (!task)
3707                 goto fail;
3708 
3709         /* Attempt to start with the tid of a thread */
3710         if (tid && nr) {
3711                 pos = find_task_by_pid_ns(tid, ns);
3712                 if (pos && same_thread_group(pos, task))
3713                         goto found;
3714         }
3715 
3716         /* If nr exceeds the number of threads there is nothing todo */
3717         if (nr >= get_nr_threads(task))
3718                 goto fail;
3719 
3720         /* If we haven't found our starting place yet start
3721          * with the leader and walk nr threads forward.
3722          */
3723         pos = task = task->group_leader;
3724         do {
3725                 if (!nr--)
3726                         goto found;
3727         } while_each_thread(task, pos);
3728 fail:
3729         pos = NULL;
3730         goto out;
3731 found:
3732         get_task_struct(pos);
3733 out:
3734         rcu_read_unlock();
3735         return pos;
3736 }
3737 
3738 /*
3739  * Find the next thread in the thread list.
3740  * Return NULL if there is an error or no next thread.
3741  *
3742  * The reference to the input task_struct is released.
3743  */
3744 static struct task_struct *next_tid(struct task_struct *start)
3745 {
3746         struct task_struct *pos = NULL;
3747         rcu_read_lock();
3748         if (pid_alive(start)) {
3749                 pos = next_thread(start);
3750                 if (thread_group_leader(pos))
3751                         pos = NULL;
3752                 else
3753                         get_task_struct(pos);
3754         }
3755         rcu_read_unlock();
3756         put_task_struct(start);
3757         return pos;
3758 }
3759 
3760 /* for the /proc/TGID/task/ directories */
3761 static int proc_task_readdir(struct file *file, struct dir_context *ctx)
3762 {
3763         struct inode *inode = file_inode(file);
3764         struct task_struct *task;
3765         struct pid_namespace *ns;
3766         int tid;
3767 
3768         if (proc_inode_is_dead(inode))
3769                 return -ENOENT;
3770 
3771         if (!dir_emit_dots(file, ctx))
3772                 return 0;
3773 
3774         /* f_version caches the tgid value that the last readdir call couldn't
3775          * return. lseek aka telldir automagically resets f_version to 0.
3776          */
3777         ns = proc_pid_ns(inode);
3778         tid = (int)file->f_version;
3779         file->f_version = 0;
3780         for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
3781              task;
3782              task = next_tid(task), ctx->pos++) {
3783                 char name[10 + 1];
3784                 unsigned int len;
3785                 tid = task_pid_nr_ns(task, ns);
3786                 len = snprintf(name, sizeof(name), "%u", tid);
3787                 if (!proc_fill_cache(file, ctx, name, len,
3788                                 proc_task_instantiate, task, NULL)) {
3789                         /* returning this tgid failed, save it as the first
3790                          * pid for the next readir call */
3791                         file->f_version = (u64)tid;
3792                         put_task_struct(task);
3793                         break;
3794                 }
3795         }
3796 
3797         return 0;
3798 }
3799 
3800 static int proc_task_getattr(const struct path *path, struct kstat *stat,
3801                              u32 request_mask, unsigned int query_flags)
3802 {
3803         struct inode *inode = d_inode(path->dentry);
3804         struct task_struct *p = get_proc_task(inode);
3805         generic_fillattr(inode, stat);
3806 
3807         if (p) {
3808                 stat->nlink += get_nr_threads(p);
3809                 put_task_struct(p);
3810         }
3811 
3812         return 0;
3813 }
3814 
3815 static const struct inode_operations proc_task_inode_operations = {
3816         .lookup         = proc_task_lookup,
3817         .getattr        = proc_task_getattr,
3818         .setattr        = proc_setattr,
3819         .permission     = proc_pid_permission,
3820 };
3821 
3822 static const struct file_operations proc_task_operations = {
3823         .read           = generic_read_dir,
3824         .iterate_shared = proc_task_readdir,
3825         .llseek         = generic_file_llseek,
3826 };
3827 
3828 void __init set_proc_pid_nlink(void)
3829 {
3830         nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3831         nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
3832 }
3833 

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