cifs: don't instantiate new dentries in readdir for inodes that need to be revalidate...
[linux-3.10.git] / fs / proc / base.c
1 /*
2  *  linux/fs/proc/base.c
3  *
4  *  Copyright (C) 1991, 1992 Linus Torvalds
5  *
6  *  proc base directory handling functions
7  *
8  *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
9  *  Instead of using magical inumbers to determine the kind of object
10  *  we allocate and fill in-core inodes upon lookup. They don't even
11  *  go into icache. We cache the reference to task_struct upon lookup too.
12  *  Eventually it should become a filesystem in its own. We don't use the
13  *  rest of procfs anymore.
14  *
15  *
16  *  Changelog:
17  *  17-Jan-2005
18  *  Allan Bezerra
19  *  Bruna Moreira <bruna.moreira@indt.org.br>
20  *  Edjard Mota <edjard.mota@indt.org.br>
21  *  Ilias Biris <ilias.biris@indt.org.br>
22  *  Mauricio Lin <mauricio.lin@indt.org.br>
23  *
24  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
25  *
26  *  A new process specific entry (smaps) included in /proc. It shows the
27  *  size of rss for each memory area. The maps entry lacks information
28  *  about physical memory size (rss) for each mapped file, i.e.,
29  *  rss information for executables and library files.
30  *  This additional information is useful for any tools that need to know
31  *  about physical memory consumption for a process specific library.
32  *
33  *  Changelog:
34  *  21-Feb-2005
35  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
36  *  Pud inclusion in the page table walking.
37  *
38  *  ChangeLog:
39  *  10-Mar-2005
40  *  10LE Instituto Nokia de Tecnologia - INdT:
41  *  A better way to walks through the page table as suggested by Hugh Dickins.
42  *
43  *  Simo Piiroinen <simo.piiroinen@nokia.com>:
44  *  Smaps information related to shared, private, clean and dirty pages.
45  *
46  *  Paul Mundt <paul.mundt@nokia.com>:
47  *  Overall revision about smaps.
48  */
49
50 #include <asm/uaccess.h>
51
52 #include <linux/errno.h>
53 #include <linux/time.h>
54 #include <linux/proc_fs.h>
55 #include <linux/stat.h>
56 #include <linux/task_io_accounting_ops.h>
57 #include <linux/init.h>
58 #include <linux/capability.h>
59 #include <linux/file.h>
60 #include <linux/fdtable.h>
61 #include <linux/string.h>
62 #include <linux/seq_file.h>
63 #include <linux/namei.h>
64 #include <linux/mnt_namespace.h>
65 #include <linux/mm.h>
66 #include <linux/swap.h>
67 #include <linux/rcupdate.h>
68 #include <linux/kallsyms.h>
69 #include <linux/stacktrace.h>
70 #include <linux/resource.h>
71 #include <linux/module.h>
72 #include <linux/mount.h>
73 #include <linux/security.h>
74 #include <linux/ptrace.h>
75 #include <linux/tracehook.h>
76 #include <linux/printk.h>
77 #include <linux/cgroup.h>
78 #include <linux/cpuset.h>
79 #include <linux/audit.h>
80 #include <linux/poll.h>
81 #include <linux/nsproxy.h>
82 #include <linux/oom.h>
83 #include <linux/elf.h>
84 #include <linux/pid_namespace.h>
85 #include <linux/user_namespace.h>
86 #include <linux/fs_struct.h>
87 #include <linux/slab.h>
88 #include <linux/flex_array.h>
89 #include <linux/posix-timers.h>
90 #ifdef CONFIG_HARDWALL
91 #include <asm/hardwall.h>
92 #endif
93 #include <trace/events/oom.h>
94 #include "internal.h"
95 #include "fd.h"
96
97 /* NOTE:
98  *      Implementing inode permission operations in /proc is almost
99  *      certainly an error.  Permission checks need to happen during
100  *      each system call not at open time.  The reason is that most of
101  *      what we wish to check for permissions in /proc varies at runtime.
102  *
103  *      The classic example of a problem is opening file descriptors
104  *      in /proc for a task before it execs a suid executable.
105  */
106
107 struct pid_entry {
108         char *name;
109         int len;
110         umode_t mode;
111         const struct inode_operations *iop;
112         const struct file_operations *fop;
113         union proc_op op;
114 };
115
116 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
117         .name = (NAME),                                 \
118         .len  = sizeof(NAME) - 1,                       \
119         .mode = MODE,                                   \
120         .iop  = IOP,                                    \
121         .fop  = FOP,                                    \
122         .op   = OP,                                     \
123 }
124
125 #define DIR(NAME, MODE, iops, fops)     \
126         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
127 #define LNK(NAME, get_link)                                     \
128         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
129                 &proc_pid_link_inode_operations, NULL,          \
130                 { .proc_get_link = get_link } )
131 #define REG(NAME, MODE, fops)                           \
132         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
133 #define INF(NAME, MODE, read)                           \
134         NOD(NAME, (S_IFREG|(MODE)),                     \
135                 NULL, &proc_info_file_operations,       \
136                 { .proc_read = read } )
137 #define ONE(NAME, MODE, show)                           \
138         NOD(NAME, (S_IFREG|(MODE)),                     \
139                 NULL, &proc_single_file_operations,     \
140                 { .proc_show = show } )
141
142 /*
143  * Count the number of hardlinks for the pid_entry table, excluding the .
144  * and .. links.
145  */
146 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
147         unsigned int n)
148 {
149         unsigned int i;
150         unsigned int count;
151
152         count = 0;
153         for (i = 0; i < n; ++i) {
154                 if (S_ISDIR(entries[i].mode))
155                         ++count;
156         }
157
158         return count;
159 }
160
161 static int get_task_root(struct task_struct *task, struct path *root)
162 {
163         int result = -ENOENT;
164
165         task_lock(task);
166         if (task->fs) {
167                 get_fs_root(task->fs, root);
168                 result = 0;
169         }
170         task_unlock(task);
171         return result;
172 }
173
174 static int proc_cwd_link(struct dentry *dentry, struct path *path)
175 {
176         struct task_struct *task = get_proc_task(dentry->d_inode);
177         int result = -ENOENT;
178
179         if (task) {
180                 task_lock(task);
181                 if (task->fs) {
182                         get_fs_pwd(task->fs, path);
183                         result = 0;
184                 }
185                 task_unlock(task);
186                 put_task_struct(task);
187         }
188         return result;
189 }
190
191 static int proc_root_link(struct dentry *dentry, struct path *path)
192 {
193         struct task_struct *task = get_proc_task(dentry->d_inode);
194         int result = -ENOENT;
195
196         if (task) {
197                 result = get_task_root(task, path);
198                 put_task_struct(task);
199         }
200         return result;
201 }
202
203 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
204 {
205         int res = 0;
206         unsigned int len;
207         struct mm_struct *mm = get_task_mm(task);
208         if (!mm)
209                 goto out;
210         if (!mm->arg_end)
211                 goto out_mm;    /* Shh! No looking before we're done */
212
213         len = mm->arg_end - mm->arg_start;
214  
215         if (len > PAGE_SIZE)
216                 len = PAGE_SIZE;
217  
218         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
219
220         // If the nul at the end of args has been overwritten, then
221         // assume application is using setproctitle(3).
222         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
223                 len = strnlen(buffer, res);
224                 if (len < res) {
225                     res = len;
226                 } else {
227                         len = mm->env_end - mm->env_start;
228                         if (len > PAGE_SIZE - res)
229                                 len = PAGE_SIZE - res;
230                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
231                         res = strnlen(buffer, res);
232                 }
233         }
234 out_mm:
235         mmput(mm);
236 out:
237         return res;
238 }
239
240 static int proc_pid_auxv(struct task_struct *task, char *buffer)
241 {
242         struct mm_struct *mm = mm_access(task, PTRACE_MODE_READ);
243         int res = PTR_ERR(mm);
244         if (mm && !IS_ERR(mm)) {
245                 unsigned int nwords = 0;
246                 do {
247                         nwords += 2;
248                 } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
249                 res = nwords * sizeof(mm->saved_auxv[0]);
250                 if (res > PAGE_SIZE)
251                         res = PAGE_SIZE;
252                 memcpy(buffer, mm->saved_auxv, res);
253                 mmput(mm);
254         }
255         return res;
256 }
257
258
259 #ifdef CONFIG_KALLSYMS
260 /*
261  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
262  * Returns the resolved symbol.  If that fails, simply return the address.
263  */
264 static int proc_pid_wchan(struct task_struct *task, char *buffer)
265 {
266         unsigned long wchan;
267         char symname[KSYM_NAME_LEN];
268
269         wchan = get_wchan(task);
270
271         if (lookup_symbol_name(wchan, symname) < 0)
272                 if (!ptrace_may_access(task, PTRACE_MODE_READ))
273                         return 0;
274                 else
275                         return sprintf(buffer, "%lu", wchan);
276         else
277                 return sprintf(buffer, "%s", symname);
278 }
279 #endif /* CONFIG_KALLSYMS */
280
281 static int lock_trace(struct task_struct *task)
282 {
283         int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
284         if (err)
285                 return err;
286         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
287                 mutex_unlock(&task->signal->cred_guard_mutex);
288                 return -EPERM;
289         }
290         return 0;
291 }
292
293 static void unlock_trace(struct task_struct *task)
294 {
295         mutex_unlock(&task->signal->cred_guard_mutex);
296 }
297
298 #ifdef CONFIG_STACKTRACE
299
300 #define MAX_STACK_TRACE_DEPTH   64
301
302 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
303                           struct pid *pid, struct task_struct *task)
304 {
305         struct stack_trace trace;
306         unsigned long *entries;
307         int err;
308         int i;
309
310         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
311         if (!entries)
312                 return -ENOMEM;
313
314         trace.nr_entries        = 0;
315         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
316         trace.entries           = entries;
317         trace.skip              = 0;
318
319         err = lock_trace(task);
320         if (!err) {
321                 save_stack_trace_tsk(task, &trace);
322
323                 for (i = 0; i < trace.nr_entries; i++) {
324                         seq_printf(m, "[<%pK>] %pS\n",
325                                    (void *)entries[i], (void *)entries[i]);
326                 }
327                 unlock_trace(task);
328         }
329         kfree(entries);
330
331         return err;
332 }
333 #endif
334
335 #ifdef CONFIG_SCHEDSTATS
336 /*
337  * Provides /proc/PID/schedstat
338  */
339 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
340 {
341         return sprintf(buffer, "%llu %llu %lu\n",
342                         (unsigned long long)task->se.sum_exec_runtime,
343                         (unsigned long long)task->sched_info.run_delay,
344                         task->sched_info.pcount);
345 }
346 #endif
347
348 #ifdef CONFIG_LATENCYTOP
349 static int lstats_show_proc(struct seq_file *m, void *v)
350 {
351         int i;
352         struct inode *inode = m->private;
353         struct task_struct *task = get_proc_task(inode);
354
355         if (!task)
356                 return -ESRCH;
357         seq_puts(m, "Latency Top version : v0.1\n");
358         for (i = 0; i < 32; i++) {
359                 struct latency_record *lr = &task->latency_record[i];
360                 if (lr->backtrace[0]) {
361                         int q;
362                         seq_printf(m, "%i %li %li",
363                                    lr->count, lr->time, lr->max);
364                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
365                                 unsigned long bt = lr->backtrace[q];
366                                 if (!bt)
367                                         break;
368                                 if (bt == ULONG_MAX)
369                                         break;
370                                 seq_printf(m, " %ps", (void *)bt);
371                         }
372                         seq_putc(m, '\n');
373                 }
374
375         }
376         put_task_struct(task);
377         return 0;
378 }
379
380 static int lstats_open(struct inode *inode, struct file *file)
381 {
382         return single_open(file, lstats_show_proc, inode);
383 }
384
385 static ssize_t lstats_write(struct file *file, const char __user *buf,
386                             size_t count, loff_t *offs)
387 {
388         struct task_struct *task = get_proc_task(file_inode(file));
389
390         if (!task)
391                 return -ESRCH;
392         clear_all_latency_tracing(task);
393         put_task_struct(task);
394
395         return count;
396 }
397
398 static const struct file_operations proc_lstats_operations = {
399         .open           = lstats_open,
400         .read           = seq_read,
401         .write          = lstats_write,
402         .llseek         = seq_lseek,
403         .release        = single_release,
404 };
405
406 #endif
407
408 #ifdef CONFIG_CGROUPS
409 static int cgroup_open(struct inode *inode, struct file *file)
410 {
411         struct pid *pid = PROC_I(inode)->pid;
412         return single_open(file, proc_cgroup_show, pid);
413 }
414
415 static const struct file_operations proc_cgroup_operations = {
416         .open           = cgroup_open,
417         .read           = seq_read,
418         .llseek         = seq_lseek,
419         .release        = single_release,
420 };
421 #endif
422
423 #ifdef CONFIG_PROC_PID_CPUSET
424
425 static int cpuset_open(struct inode *inode, struct file *file)
426 {
427         struct pid *pid = PROC_I(inode)->pid;
428         return single_open(file, proc_cpuset_show, pid);
429 }
430
431 static const struct file_operations proc_cpuset_operations = {
432         .open           = cpuset_open,
433         .read           = seq_read,
434         .llseek         = seq_lseek,
435         .release        = single_release,
436 };
437 #endif
438
439 static int proc_oom_score(struct task_struct *task, char *buffer)
440 {
441         unsigned long totalpages = totalram_pages + total_swap_pages;
442         unsigned long points = 0;
443
444         read_lock(&tasklist_lock);
445         if (pid_alive(task))
446                 points = oom_badness(task, NULL, NULL, totalpages) *
447                                                 1000 / totalpages;
448         read_unlock(&tasklist_lock);
449         return sprintf(buffer, "%lu\n", points);
450 }
451
452 struct limit_names {
453         char *name;
454         char *unit;
455 };
456
457 static const struct limit_names lnames[RLIM_NLIMITS] = {
458         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
459         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
460         [RLIMIT_DATA] = {"Max data size", "bytes"},
461         [RLIMIT_STACK] = {"Max stack size", "bytes"},
462         [RLIMIT_CORE] = {"Max core file size", "bytes"},
463         [RLIMIT_RSS] = {"Max resident set", "bytes"},
464         [RLIMIT_NPROC] = {"Max processes", "processes"},
465         [RLIMIT_NOFILE] = {"Max open files", "files"},
466         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
467         [RLIMIT_AS] = {"Max address space", "bytes"},
468         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
469         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
470         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
471         [RLIMIT_NICE] = {"Max nice priority", NULL},
472         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
473         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
474 };
475
476 /* Display limits for a process */
477 static int proc_pid_limits(struct task_struct *task, char *buffer)
478 {
479         unsigned int i;
480         int count = 0;
481         unsigned long flags;
482         char *bufptr = buffer;
483
484         struct rlimit rlim[RLIM_NLIMITS];
485
486         if (!lock_task_sighand(task, &flags))
487                 return 0;
488         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
489         unlock_task_sighand(task, &flags);
490
491         /*
492          * print the file header
493          */
494         count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
495                         "Limit", "Soft Limit", "Hard Limit", "Units");
496
497         for (i = 0; i < RLIM_NLIMITS; i++) {
498                 if (rlim[i].rlim_cur == RLIM_INFINITY)
499                         count += sprintf(&bufptr[count], "%-25s %-20s ",
500                                          lnames[i].name, "unlimited");
501                 else
502                         count += sprintf(&bufptr[count], "%-25s %-20lu ",
503                                          lnames[i].name, rlim[i].rlim_cur);
504
505                 if (rlim[i].rlim_max == RLIM_INFINITY)
506                         count += sprintf(&bufptr[count], "%-20s ", "unlimited");
507                 else
508                         count += sprintf(&bufptr[count], "%-20lu ",
509                                          rlim[i].rlim_max);
510
511                 if (lnames[i].unit)
512                         count += sprintf(&bufptr[count], "%-10s\n",
513                                          lnames[i].unit);
514                 else
515                         count += sprintf(&bufptr[count], "\n");
516         }
517
518         return count;
519 }
520
521 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
522 static int proc_pid_syscall(struct task_struct *task, char *buffer)
523 {
524         long nr;
525         unsigned long args[6], sp, pc;
526         int res = lock_trace(task);
527         if (res)
528                 return res;
529
530         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
531                 res = sprintf(buffer, "running\n");
532         else if (nr < 0)
533                 res = sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
534         else
535                 res = sprintf(buffer,
536                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
537                        nr,
538                        args[0], args[1], args[2], args[3], args[4], args[5],
539                        sp, pc);
540         unlock_trace(task);
541         return res;
542 }
543 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
544
545 /************************************************************************/
546 /*                       Here the fs part begins                        */
547 /************************************************************************/
548
549 /* permission checks */
550 static int proc_fd_access_allowed(struct inode *inode)
551 {
552         struct task_struct *task;
553         int allowed = 0;
554         /* Allow access to a task's file descriptors if it is us or we
555          * may use ptrace attach to the process and find out that
556          * information.
557          */
558         task = get_proc_task(inode);
559         if (task) {
560                 allowed = ptrace_may_access(task, PTRACE_MODE_READ);
561                 put_task_struct(task);
562         }
563         return allowed;
564 }
565
566 int proc_setattr(struct dentry *dentry, struct iattr *attr)
567 {
568         int error;
569         struct inode *inode = dentry->d_inode;
570
571         if (attr->ia_valid & ATTR_MODE)
572                 return -EPERM;
573
574         error = inode_change_ok(inode, attr);
575         if (error)
576                 return error;
577
578         setattr_copy(inode, attr);
579         mark_inode_dirty(inode);
580         return 0;
581 }
582
583 /*
584  * May current process learn task's sched/cmdline info (for hide_pid_min=1)
585  * or euid/egid (for hide_pid_min=2)?
586  */
587 static bool has_pid_permissions(struct pid_namespace *pid,
588                                  struct task_struct *task,
589                                  int hide_pid_min)
590 {
591         if (pid->hide_pid < hide_pid_min)
592                 return true;
593         if (in_group_p(pid->pid_gid))
594                 return true;
595         return ptrace_may_access(task, PTRACE_MODE_READ);
596 }
597
598
599 static int proc_pid_permission(struct inode *inode, int mask)
600 {
601         struct pid_namespace *pid = inode->i_sb->s_fs_info;
602         struct task_struct *task;
603         bool has_perms;
604
605         task = get_proc_task(inode);
606         if (!task)
607                 return -ESRCH;
608         has_perms = has_pid_permissions(pid, task, 1);
609         put_task_struct(task);
610
611         if (!has_perms) {
612                 if (pid->hide_pid == 2) {
613                         /*
614                          * Let's make getdents(), stat(), and open()
615                          * consistent with each other.  If a process
616                          * may not stat() a file, it shouldn't be seen
617                          * in procfs at all.
618                          */
619                         return -ENOENT;
620                 }
621
622                 return -EPERM;
623         }
624         return generic_permission(inode, mask);
625 }
626
627
628
629 static const struct inode_operations proc_def_inode_operations = {
630         .setattr        = proc_setattr,
631 };
632
633 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
634
635 static ssize_t proc_info_read(struct file * file, char __user * buf,
636                           size_t count, loff_t *ppos)
637 {
638         struct inode * inode = file_inode(file);
639         unsigned long page;
640         ssize_t length;
641         struct task_struct *task = get_proc_task(inode);
642
643         length = -ESRCH;
644         if (!task)
645                 goto out_no_task;
646
647         if (count > PROC_BLOCK_SIZE)
648                 count = PROC_BLOCK_SIZE;
649
650         length = -ENOMEM;
651         if (!(page = __get_free_page(GFP_TEMPORARY)))
652                 goto out;
653
654         length = PROC_I(inode)->op.proc_read(task, (char*)page);
655
656         if (length >= 0)
657                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
658         free_page(page);
659 out:
660         put_task_struct(task);
661 out_no_task:
662         return length;
663 }
664
665 static const struct file_operations proc_info_file_operations = {
666         .read           = proc_info_read,
667         .llseek         = generic_file_llseek,
668 };
669
670 static int proc_single_show(struct seq_file *m, void *v)
671 {
672         struct inode *inode = m->private;
673         struct pid_namespace *ns;
674         struct pid *pid;
675         struct task_struct *task;
676         int ret;
677
678         ns = inode->i_sb->s_fs_info;
679         pid = proc_pid(inode);
680         task = get_pid_task(pid, PIDTYPE_PID);
681         if (!task)
682                 return -ESRCH;
683
684         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
685
686         put_task_struct(task);
687         return ret;
688 }
689
690 static int proc_single_open(struct inode *inode, struct file *filp)
691 {
692         return single_open(filp, proc_single_show, inode);
693 }
694
695 static const struct file_operations proc_single_file_operations = {
696         .open           = proc_single_open,
697         .read           = seq_read,
698         .llseek         = seq_lseek,
699         .release        = single_release,
700 };
701
702 static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
703 {
704         struct task_struct *task = get_proc_task(file_inode(file));
705         struct mm_struct *mm;
706
707         if (!task)
708                 return -ESRCH;
709
710         mm = mm_access(task, mode);
711         put_task_struct(task);
712
713         if (IS_ERR(mm))
714                 return PTR_ERR(mm);
715
716         if (mm) {
717                 /* ensure this mm_struct can't be freed */
718                 atomic_inc(&mm->mm_count);
719                 /* but do not pin its memory */
720                 mmput(mm);
721         }
722
723         file->private_data = mm;
724
725         return 0;
726 }
727
728 static int mem_open(struct inode *inode, struct file *file)
729 {
730         int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
731
732         /* OK to pass negative loff_t, we can catch out-of-range */
733         file->f_mode |= FMODE_UNSIGNED_OFFSET;
734
735         return ret;
736 }
737
738 static ssize_t mem_rw(struct file *file, char __user *buf,
739                         size_t count, loff_t *ppos, int write)
740 {
741         struct mm_struct *mm = file->private_data;
742         unsigned long addr = *ppos;
743         ssize_t copied;
744         char *page;
745
746         if (!mm)
747                 return 0;
748
749         page = (char *)__get_free_page(GFP_TEMPORARY);
750         if (!page)
751                 return -ENOMEM;
752
753         copied = 0;
754         if (!atomic_inc_not_zero(&mm->mm_users))
755                 goto free;
756
757         while (count > 0) {
758                 int this_len = min_t(int, count, PAGE_SIZE);
759
760                 if (write && copy_from_user(page, buf, this_len)) {
761                         copied = -EFAULT;
762                         break;
763                 }
764
765                 this_len = access_remote_vm(mm, addr, page, this_len, write);
766                 if (!this_len) {
767                         if (!copied)
768                                 copied = -EIO;
769                         break;
770                 }
771
772                 if (!write && copy_to_user(buf, page, this_len)) {
773                         copied = -EFAULT;
774                         break;
775                 }
776
777                 buf += this_len;
778                 addr += this_len;
779                 copied += this_len;
780                 count -= this_len;
781         }
782         *ppos = addr;
783
784         mmput(mm);
785 free:
786         free_page((unsigned long) page);
787         return copied;
788 }
789
790 static ssize_t mem_read(struct file *file, char __user *buf,
791                         size_t count, loff_t *ppos)
792 {
793         return mem_rw(file, buf, count, ppos, 0);
794 }
795
796 static ssize_t mem_write(struct file *file, const char __user *buf,
797                          size_t count, loff_t *ppos)
798 {
799         return mem_rw(file, (char __user*)buf, count, ppos, 1);
800 }
801
802 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
803 {
804         switch (orig) {
805         case 0:
806                 file->f_pos = offset;
807                 break;
808         case 1:
809                 file->f_pos += offset;
810                 break;
811         default:
812                 return -EINVAL;
813         }
814         force_successful_syscall_return();
815         return file->f_pos;
816 }
817
818 static int mem_release(struct inode *inode, struct file *file)
819 {
820         struct mm_struct *mm = file->private_data;
821         if (mm)
822                 mmdrop(mm);
823         return 0;
824 }
825
826 static const struct file_operations proc_mem_operations = {
827         .llseek         = mem_lseek,
828         .read           = mem_read,
829         .write          = mem_write,
830         .open           = mem_open,
831         .release        = mem_release,
832 };
833
834 static int environ_open(struct inode *inode, struct file *file)
835 {
836         return __mem_open(inode, file, PTRACE_MODE_READ);
837 }
838
839 static ssize_t environ_read(struct file *file, char __user *buf,
840                         size_t count, loff_t *ppos)
841 {
842         char *page;
843         unsigned long src = *ppos;
844         int ret = 0;
845         struct mm_struct *mm = file->private_data;
846
847         if (!mm)
848                 return 0;
849
850         page = (char *)__get_free_page(GFP_TEMPORARY);
851         if (!page)
852                 return -ENOMEM;
853
854         ret = 0;
855         if (!atomic_inc_not_zero(&mm->mm_users))
856                 goto free;
857         while (count > 0) {
858                 size_t this_len, max_len;
859                 int retval;
860
861                 if (src >= (mm->env_end - mm->env_start))
862                         break;
863
864                 this_len = mm->env_end - (mm->env_start + src);
865
866                 max_len = min_t(size_t, PAGE_SIZE, count);
867                 this_len = min(max_len, this_len);
868
869                 retval = access_remote_vm(mm, (mm->env_start + src),
870                         page, this_len, 0);
871
872                 if (retval <= 0) {
873                         ret = retval;
874                         break;
875                 }
876
877                 if (copy_to_user(buf, page, retval)) {
878                         ret = -EFAULT;
879                         break;
880                 }
881
882                 ret += retval;
883                 src += retval;
884                 buf += retval;
885                 count -= retval;
886         }
887         *ppos = src;
888         mmput(mm);
889
890 free:
891         free_page((unsigned long) page);
892         return ret;
893 }
894
895 static const struct file_operations proc_environ_operations = {
896         .open           = environ_open,
897         .read           = environ_read,
898         .llseek         = generic_file_llseek,
899         .release        = mem_release,
900 };
901
902 static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
903                             loff_t *ppos)
904 {
905         struct task_struct *task = get_proc_task(file_inode(file));
906         char buffer[PROC_NUMBUF];
907         int oom_adj = OOM_ADJUST_MIN;
908         size_t len;
909         unsigned long flags;
910
911         if (!task)
912                 return -ESRCH;
913         if (lock_task_sighand(task, &flags)) {
914                 if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
915                         oom_adj = OOM_ADJUST_MAX;
916                 else
917                         oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
918                                   OOM_SCORE_ADJ_MAX;
919                 unlock_task_sighand(task, &flags);
920         }
921         put_task_struct(task);
922         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
923         return simple_read_from_buffer(buf, count, ppos, buffer, len);
924 }
925
926 static ssize_t oom_adj_write(struct file *file, const char __user *buf,
927                              size_t count, loff_t *ppos)
928 {
929         struct task_struct *task;
930         char buffer[PROC_NUMBUF];
931         int oom_adj;
932         unsigned long flags;
933         int err;
934
935         memset(buffer, 0, sizeof(buffer));
936         if (count > sizeof(buffer) - 1)
937                 count = sizeof(buffer) - 1;
938         if (copy_from_user(buffer, buf, count)) {
939                 err = -EFAULT;
940                 goto out;
941         }
942
943         err = kstrtoint(strstrip(buffer), 0, &oom_adj);
944         if (err)
945                 goto out;
946         if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
947              oom_adj != OOM_DISABLE) {
948                 err = -EINVAL;
949                 goto out;
950         }
951
952         task = get_proc_task(file_inode(file));
953         if (!task) {
954                 err = -ESRCH;
955                 goto out;
956         }
957
958         task_lock(task);
959         if (!task->mm) {
960                 err = -EINVAL;
961                 goto err_task_lock;
962         }
963
964         if (!lock_task_sighand(task, &flags)) {
965                 err = -ESRCH;
966                 goto err_task_lock;
967         }
968
969         /*
970          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
971          * value is always attainable.
972          */
973         if (oom_adj == OOM_ADJUST_MAX)
974                 oom_adj = OOM_SCORE_ADJ_MAX;
975         else
976                 oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
977
978         if (oom_adj < task->signal->oom_score_adj &&
979             !capable(CAP_SYS_RESOURCE)) {
980                 err = -EACCES;
981                 goto err_sighand;
982         }
983
984         /*
985          * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
986          * /proc/pid/oom_score_adj instead.
987          */
988         pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
989                   current->comm, task_pid_nr(current), task_pid_nr(task),
990                   task_pid_nr(task));
991
992         task->signal->oom_score_adj = oom_adj;
993         trace_oom_score_adj_update(task);
994 err_sighand:
995         unlock_task_sighand(task, &flags);
996 err_task_lock:
997         task_unlock(task);
998         put_task_struct(task);
999 out:
1000         return err < 0 ? err : count;
1001 }
1002
1003 static const struct file_operations proc_oom_adj_operations = {
1004         .read           = oom_adj_read,
1005         .write          = oom_adj_write,
1006         .llseek         = generic_file_llseek,
1007 };
1008
1009 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1010                                         size_t count, loff_t *ppos)
1011 {
1012         struct task_struct *task = get_proc_task(file_inode(file));
1013         char buffer[PROC_NUMBUF];
1014         short oom_score_adj = OOM_SCORE_ADJ_MIN;
1015         unsigned long flags;
1016         size_t len;
1017
1018         if (!task)
1019                 return -ESRCH;
1020         if (lock_task_sighand(task, &flags)) {
1021                 oom_score_adj = task->signal->oom_score_adj;
1022                 unlock_task_sighand(task, &flags);
1023         }
1024         put_task_struct(task);
1025         len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
1026         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1027 }
1028
1029 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1030                                         size_t count, loff_t *ppos)
1031 {
1032         struct task_struct *task;
1033         char buffer[PROC_NUMBUF];
1034         unsigned long flags;
1035         int oom_score_adj;
1036         int err;
1037
1038         memset(buffer, 0, sizeof(buffer));
1039         if (count > sizeof(buffer) - 1)
1040                 count = sizeof(buffer) - 1;
1041         if (copy_from_user(buffer, buf, count)) {
1042                 err = -EFAULT;
1043                 goto out;
1044         }
1045
1046         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1047         if (err)
1048                 goto out;
1049         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1050                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1051                 err = -EINVAL;
1052                 goto out;
1053         }
1054
1055         task = get_proc_task(file_inode(file));
1056         if (!task) {
1057                 err = -ESRCH;
1058                 goto out;
1059         }
1060
1061         task_lock(task);
1062         if (!task->mm) {
1063                 err = -EINVAL;
1064                 goto err_task_lock;
1065         }
1066
1067         if (!lock_task_sighand(task, &flags)) {
1068                 err = -ESRCH;
1069                 goto err_task_lock;
1070         }
1071
1072         if ((short)oom_score_adj < task->signal->oom_score_adj_min &&
1073                         !capable(CAP_SYS_RESOURCE)) {
1074                 err = -EACCES;
1075                 goto err_sighand;
1076         }
1077
1078         task->signal->oom_score_adj = (short)oom_score_adj;
1079         if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1080                 task->signal->oom_score_adj_min = (short)oom_score_adj;
1081         trace_oom_score_adj_update(task);
1082
1083 err_sighand:
1084         unlock_task_sighand(task, &flags);
1085 err_task_lock:
1086         task_unlock(task);
1087         put_task_struct(task);
1088 out:
1089         return err < 0 ? err : count;
1090 }
1091
1092 static const struct file_operations proc_oom_score_adj_operations = {
1093         .read           = oom_score_adj_read,
1094         .write          = oom_score_adj_write,
1095         .llseek         = default_llseek,
1096 };
1097
1098 #ifdef CONFIG_AUDITSYSCALL
1099 #define TMPBUFLEN 21
1100 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1101                                   size_t count, loff_t *ppos)
1102 {
1103         struct inode * inode = file_inode(file);
1104         struct task_struct *task = get_proc_task(inode);
1105         ssize_t length;
1106         char tmpbuf[TMPBUFLEN];
1107
1108         if (!task)
1109                 return -ESRCH;
1110         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1111                            from_kuid(file->f_cred->user_ns,
1112                                      audit_get_loginuid(task)));
1113         put_task_struct(task);
1114         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1115 }
1116
1117 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1118                                    size_t count, loff_t *ppos)
1119 {
1120         struct inode * inode = file_inode(file);
1121         char *page, *tmp;
1122         ssize_t length;
1123         uid_t loginuid;
1124         kuid_t kloginuid;
1125
1126         rcu_read_lock();
1127         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1128                 rcu_read_unlock();
1129                 return -EPERM;
1130         }
1131         rcu_read_unlock();
1132
1133         if (count >= PAGE_SIZE)
1134                 count = PAGE_SIZE - 1;
1135
1136         if (*ppos != 0) {
1137                 /* No partial writes. */
1138                 return -EINVAL;
1139         }
1140         page = (char*)__get_free_page(GFP_TEMPORARY);
1141         if (!page)
1142                 return -ENOMEM;
1143         length = -EFAULT;
1144         if (copy_from_user(page, buf, count))
1145                 goto out_free_page;
1146
1147         page[count] = '\0';
1148         loginuid = simple_strtoul(page, &tmp, 10);
1149         if (tmp == page) {
1150                 length = -EINVAL;
1151                 goto out_free_page;
1152
1153         }
1154         kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
1155         if (!uid_valid(kloginuid)) {
1156                 length = -EINVAL;
1157                 goto out_free_page;
1158         }
1159
1160         length = audit_set_loginuid(kloginuid);
1161         if (likely(length == 0))
1162                 length = count;
1163
1164 out_free_page:
1165         free_page((unsigned long) page);
1166         return length;
1167 }
1168
1169 static const struct file_operations proc_loginuid_operations = {
1170         .read           = proc_loginuid_read,
1171         .write          = proc_loginuid_write,
1172         .llseek         = generic_file_llseek,
1173 };
1174
1175 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1176                                   size_t count, loff_t *ppos)
1177 {
1178         struct inode * inode = file_inode(file);
1179         struct task_struct *task = get_proc_task(inode);
1180         ssize_t length;
1181         char tmpbuf[TMPBUFLEN];
1182
1183         if (!task)
1184                 return -ESRCH;
1185         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1186                                 audit_get_sessionid(task));
1187         put_task_struct(task);
1188         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1189 }
1190
1191 static const struct file_operations proc_sessionid_operations = {
1192         .read           = proc_sessionid_read,
1193         .llseek         = generic_file_llseek,
1194 };
1195 #endif
1196
1197 #ifdef CONFIG_FAULT_INJECTION
1198 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1199                                       size_t count, loff_t *ppos)
1200 {
1201         struct task_struct *task = get_proc_task(file_inode(file));
1202         char buffer[PROC_NUMBUF];
1203         size_t len;
1204         int make_it_fail;
1205
1206         if (!task)
1207                 return -ESRCH;
1208         make_it_fail = task->make_it_fail;
1209         put_task_struct(task);
1210
1211         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1212
1213         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1214 }
1215
1216 static ssize_t proc_fault_inject_write(struct file * file,
1217                         const char __user * buf, size_t count, loff_t *ppos)
1218 {
1219         struct task_struct *task;
1220         char buffer[PROC_NUMBUF], *end;
1221         int make_it_fail;
1222
1223         if (!capable(CAP_SYS_RESOURCE))
1224                 return -EPERM;
1225         memset(buffer, 0, sizeof(buffer));
1226         if (count > sizeof(buffer) - 1)
1227                 count = sizeof(buffer) - 1;
1228         if (copy_from_user(buffer, buf, count))
1229                 return -EFAULT;
1230         make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
1231         if (*end)
1232                 return -EINVAL;
1233         task = get_proc_task(file_inode(file));
1234         if (!task)
1235                 return -ESRCH;
1236         task->make_it_fail = make_it_fail;
1237         put_task_struct(task);
1238
1239         return count;
1240 }
1241
1242 static const struct file_operations proc_fault_inject_operations = {
1243         .read           = proc_fault_inject_read,
1244         .write          = proc_fault_inject_write,
1245         .llseek         = generic_file_llseek,
1246 };
1247 #endif
1248
1249
1250 #ifdef CONFIG_SCHED_DEBUG
1251 /*
1252  * Print out various scheduling related per-task fields:
1253  */
1254 static int sched_show(struct seq_file *m, void *v)
1255 {
1256         struct inode *inode = m->private;
1257         struct task_struct *p;
1258
1259         p = get_proc_task(inode);
1260         if (!p)
1261                 return -ESRCH;
1262         proc_sched_show_task(p, m);
1263
1264         put_task_struct(p);
1265
1266         return 0;
1267 }
1268
1269 static ssize_t
1270 sched_write(struct file *file, const char __user *buf,
1271             size_t count, loff_t *offset)
1272 {
1273         struct inode *inode = file_inode(file);
1274         struct task_struct *p;
1275
1276         p = get_proc_task(inode);
1277         if (!p)
1278                 return -ESRCH;
1279         proc_sched_set_task(p);
1280
1281         put_task_struct(p);
1282
1283         return count;
1284 }
1285
1286 static int sched_open(struct inode *inode, struct file *filp)
1287 {
1288         return single_open(filp, sched_show, inode);
1289 }
1290
1291 static const struct file_operations proc_pid_sched_operations = {
1292         .open           = sched_open,
1293         .read           = seq_read,
1294         .write          = sched_write,
1295         .llseek         = seq_lseek,
1296         .release        = single_release,
1297 };
1298
1299 #endif
1300
1301 #ifdef CONFIG_SCHED_AUTOGROUP
1302 /*
1303  * Print out autogroup related information:
1304  */
1305 static int sched_autogroup_show(struct seq_file *m, void *v)
1306 {
1307         struct inode *inode = m->private;
1308         struct task_struct *p;
1309
1310         p = get_proc_task(inode);
1311         if (!p)
1312                 return -ESRCH;
1313         proc_sched_autogroup_show_task(p, m);
1314
1315         put_task_struct(p);
1316
1317         return 0;
1318 }
1319
1320 static ssize_t
1321 sched_autogroup_write(struct file *file, const char __user *buf,
1322             size_t count, loff_t *offset)
1323 {
1324         struct inode *inode = file_inode(file);
1325         struct task_struct *p;
1326         char buffer[PROC_NUMBUF];
1327         int nice;
1328         int err;
1329
1330         memset(buffer, 0, sizeof(buffer));
1331         if (count > sizeof(buffer) - 1)
1332                 count = sizeof(buffer) - 1;
1333         if (copy_from_user(buffer, buf, count))
1334                 return -EFAULT;
1335
1336         err = kstrtoint(strstrip(buffer), 0, &nice);
1337         if (err < 0)
1338                 return err;
1339
1340         p = get_proc_task(inode);
1341         if (!p)
1342                 return -ESRCH;
1343
1344         err = proc_sched_autogroup_set_nice(p, nice);
1345         if (err)
1346                 count = err;
1347
1348         put_task_struct(p);
1349
1350         return count;
1351 }
1352
1353 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1354 {
1355         int ret;
1356
1357         ret = single_open(filp, sched_autogroup_show, NULL);
1358         if (!ret) {
1359                 struct seq_file *m = filp->private_data;
1360
1361                 m->private = inode;
1362         }
1363         return ret;
1364 }
1365
1366 static const struct file_operations proc_pid_sched_autogroup_operations = {
1367         .open           = sched_autogroup_open,
1368         .read           = seq_read,
1369         .write          = sched_autogroup_write,
1370         .llseek         = seq_lseek,
1371         .release        = single_release,
1372 };
1373
1374 #endif /* CONFIG_SCHED_AUTOGROUP */
1375
1376 static ssize_t comm_write(struct file *file, const char __user *buf,
1377                                 size_t count, loff_t *offset)
1378 {
1379         struct inode *inode = file_inode(file);
1380         struct task_struct *p;
1381         char buffer[TASK_COMM_LEN];
1382         const size_t maxlen = sizeof(buffer) - 1;
1383
1384         memset(buffer, 0, sizeof(buffer));
1385         if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
1386                 return -EFAULT;
1387
1388         p = get_proc_task(inode);
1389         if (!p)
1390                 return -ESRCH;
1391
1392         if (same_thread_group(current, p))
1393                 set_task_comm(p, buffer);
1394         else
1395                 count = -EINVAL;
1396
1397         put_task_struct(p);
1398
1399         return count;
1400 }
1401
1402 static int comm_show(struct seq_file *m, void *v)
1403 {
1404         struct inode *inode = m->private;
1405         struct task_struct *p;
1406
1407         p = get_proc_task(inode);
1408         if (!p)
1409                 return -ESRCH;
1410
1411         task_lock(p);
1412         seq_printf(m, "%s\n", p->comm);
1413         task_unlock(p);
1414
1415         put_task_struct(p);
1416
1417         return 0;
1418 }
1419
1420 static int comm_open(struct inode *inode, struct file *filp)
1421 {
1422         return single_open(filp, comm_show, inode);
1423 }
1424
1425 static const struct file_operations proc_pid_set_comm_operations = {
1426         .open           = comm_open,
1427         .read           = seq_read,
1428         .write          = comm_write,
1429         .llseek         = seq_lseek,
1430         .release        = single_release,
1431 };
1432
1433 static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
1434 {
1435         struct task_struct *task;
1436         struct mm_struct *mm;
1437         struct file *exe_file;
1438
1439         task = get_proc_task(dentry->d_inode);
1440         if (!task)
1441                 return -ENOENT;
1442         mm = get_task_mm(task);
1443         put_task_struct(task);
1444         if (!mm)
1445                 return -ENOENT;
1446         exe_file = get_mm_exe_file(mm);
1447         mmput(mm);
1448         if (exe_file) {
1449                 *exe_path = exe_file->f_path;
1450                 path_get(&exe_file->f_path);
1451                 fput(exe_file);
1452                 return 0;
1453         } else
1454                 return -ENOENT;
1455 }
1456
1457 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1458 {
1459         struct inode *inode = dentry->d_inode;
1460         struct path path;
1461         int error = -EACCES;
1462
1463         /* Are we allowed to snoop on the tasks file descriptors? */
1464         if (!proc_fd_access_allowed(inode))
1465                 goto out;
1466
1467         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1468         if (error)
1469                 goto out;
1470
1471         nd_jump_link(nd, &path);
1472         return NULL;
1473 out:
1474         return ERR_PTR(error);
1475 }
1476
1477 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1478 {
1479         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1480         char *pathname;
1481         int len;
1482
1483         if (!tmp)
1484                 return -ENOMEM;
1485
1486         pathname = d_path(path, tmp, PAGE_SIZE);
1487         len = PTR_ERR(pathname);
1488         if (IS_ERR(pathname))
1489                 goto out;
1490         len = tmp + PAGE_SIZE - 1 - pathname;
1491
1492         if (len > buflen)
1493                 len = buflen;
1494         if (copy_to_user(buffer, pathname, len))
1495                 len = -EFAULT;
1496  out:
1497         free_page((unsigned long)tmp);
1498         return len;
1499 }
1500
1501 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1502 {
1503         int error = -EACCES;
1504         struct inode *inode = dentry->d_inode;
1505         struct path path;
1506
1507         /* Are we allowed to snoop on the tasks file descriptors? */
1508         if (!proc_fd_access_allowed(inode))
1509                 goto out;
1510
1511         error = PROC_I(inode)->op.proc_get_link(dentry, &path);
1512         if (error)
1513                 goto out;
1514
1515         error = do_proc_readlink(&path, buffer, buflen);
1516         path_put(&path);
1517 out:
1518         return error;
1519 }
1520
1521 const struct inode_operations proc_pid_link_inode_operations = {
1522         .readlink       = proc_pid_readlink,
1523         .follow_link    = proc_pid_follow_link,
1524         .setattr        = proc_setattr,
1525 };
1526
1527
1528 /* building an inode */
1529
1530 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1531 {
1532         struct inode * inode;
1533         struct proc_inode *ei;
1534         const struct cred *cred;
1535
1536         /* We need a new inode */
1537
1538         inode = new_inode(sb);
1539         if (!inode)
1540                 goto out;
1541
1542         /* Common stuff */
1543         ei = PROC_I(inode);
1544         inode->i_ino = get_next_ino();
1545         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1546         inode->i_op = &proc_def_inode_operations;
1547
1548         /*
1549          * grab the reference to task.
1550          */
1551         ei->pid = get_task_pid(task, PIDTYPE_PID);
1552         if (!ei->pid)
1553                 goto out_unlock;
1554
1555         if (task_dumpable(task)) {
1556                 rcu_read_lock();
1557                 cred = __task_cred(task);
1558                 inode->i_uid = cred->euid;
1559                 inode->i_gid = cred->egid;
1560                 rcu_read_unlock();
1561         }
1562         security_task_to_inode(task, inode);
1563
1564 out:
1565         return inode;
1566
1567 out_unlock:
1568         iput(inode);
1569         return NULL;
1570 }
1571
1572 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1573 {
1574         struct inode *inode = dentry->d_inode;
1575         struct task_struct *task;
1576         const struct cred *cred;
1577         struct pid_namespace *pid = dentry->d_sb->s_fs_info;
1578
1579         generic_fillattr(inode, stat);
1580
1581         rcu_read_lock();
1582         stat->uid = GLOBAL_ROOT_UID;
1583         stat->gid = GLOBAL_ROOT_GID;
1584         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1585         if (task) {
1586                 if (!has_pid_permissions(pid, task, 2)) {
1587                         rcu_read_unlock();
1588                         /*
1589                          * This doesn't prevent learning whether PID exists,
1590                          * it only makes getattr() consistent with readdir().
1591                          */
1592                         return -ENOENT;
1593                 }
1594                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1595                     task_dumpable(task)) {
1596                         cred = __task_cred(task);
1597                         stat->uid = cred->euid;
1598                         stat->gid = cred->egid;
1599                 }
1600         }
1601         rcu_read_unlock();
1602         return 0;
1603 }
1604
1605 /* dentry stuff */
1606
1607 /*
1608  *      Exceptional case: normally we are not allowed to unhash a busy
1609  * directory. In this case, however, we can do it - no aliasing problems
1610  * due to the way we treat inodes.
1611  *
1612  * Rewrite the inode's ownerships here because the owning task may have
1613  * performed a setuid(), etc.
1614  *
1615  * Before the /proc/pid/status file was created the only way to read
1616  * the effective uid of a /process was to stat /proc/pid.  Reading
1617  * /proc/pid/status is slow enough that procps and other packages
1618  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1619  * made this apply to all per process world readable and executable
1620  * directories.
1621  */
1622 int pid_revalidate(struct dentry *dentry, unsigned int flags)
1623 {
1624         struct inode *inode;
1625         struct task_struct *task;
1626         const struct cred *cred;
1627
1628         if (flags & LOOKUP_RCU)
1629                 return -ECHILD;
1630
1631         inode = dentry->d_inode;
1632         task = get_proc_task(inode);
1633
1634         if (task) {
1635                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1636                     task_dumpable(task)) {
1637                         rcu_read_lock();
1638                         cred = __task_cred(task);
1639                         inode->i_uid = cred->euid;
1640                         inode->i_gid = cred->egid;
1641                         rcu_read_unlock();
1642                 } else {
1643                         inode->i_uid = GLOBAL_ROOT_UID;
1644                         inode->i_gid = GLOBAL_ROOT_GID;
1645                 }
1646                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1647                 security_task_to_inode(task, inode);
1648                 put_task_struct(task);
1649                 return 1;
1650         }
1651         d_drop(dentry);
1652         return 0;
1653 }
1654
1655 int pid_delete_dentry(const struct dentry *dentry)
1656 {
1657         /* Is the task we represent dead?
1658          * If so, then don't put the dentry on the lru list,
1659          * kill it immediately.
1660          */
1661         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1662 }
1663
1664 const struct dentry_operations pid_dentry_operations =
1665 {
1666         .d_revalidate   = pid_revalidate,
1667         .d_delete       = pid_delete_dentry,
1668 };
1669
1670 /* Lookups */
1671
1672 /*
1673  * Fill a directory entry.
1674  *
1675  * If possible create the dcache entry and derive our inode number and
1676  * file type from dcache entry.
1677  *
1678  * Since all of the proc inode numbers are dynamically generated, the inode
1679  * numbers do not exist until the inode is cache.  This means creating the
1680  * the dcache entry in readdir is necessary to keep the inode numbers
1681  * reported by readdir in sync with the inode numbers reported
1682  * by stat.
1683  */
1684 int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1685         const char *name, int len,
1686         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1687 {
1688         struct dentry *child, *dir = filp->f_path.dentry;
1689         struct inode *inode;
1690         struct qstr qname;
1691         ino_t ino = 0;
1692         unsigned type = DT_UNKNOWN;
1693
1694         qname.name = name;
1695         qname.len  = len;
1696         qname.hash = full_name_hash(name, len);
1697
1698         child = d_lookup(dir, &qname);
1699         if (!child) {
1700                 struct dentry *new;
1701                 new = d_alloc(dir, &qname);
1702                 if (new) {
1703                         child = instantiate(dir->d_inode, new, task, ptr);
1704                         if (child)
1705                                 dput(new);
1706                         else
1707                                 child = new;
1708                 }
1709         }
1710         if (!child || IS_ERR(child) || !child->d_inode)
1711                 goto end_instantiate;
1712         inode = child->d_inode;
1713         if (inode) {
1714                 ino = inode->i_ino;
1715                 type = inode->i_mode >> 12;
1716         }
1717         dput(child);
1718 end_instantiate:
1719         if (!ino)
1720                 ino = find_inode_number(dir, &qname);
1721         if (!ino)
1722                 ino = 1;
1723         return filldir(dirent, name, len, filp->f_pos, ino, type);
1724 }
1725
1726 #ifdef CONFIG_CHECKPOINT_RESTORE
1727
1728 /*
1729  * dname_to_vma_addr - maps a dentry name into two unsigned longs
1730  * which represent vma start and end addresses.
1731  */
1732 static int dname_to_vma_addr(struct dentry *dentry,
1733                              unsigned long *start, unsigned long *end)
1734 {
1735         if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
1736                 return -EINVAL;
1737
1738         return 0;
1739 }
1740
1741 static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
1742 {
1743         unsigned long vm_start, vm_end;
1744         bool exact_vma_exists = false;
1745         struct mm_struct *mm = NULL;
1746         struct task_struct *task;
1747         const struct cred *cred;
1748         struct inode *inode;
1749         int status = 0;
1750
1751         if (flags & LOOKUP_RCU)
1752                 return -ECHILD;
1753
1754         if (!capable(CAP_SYS_ADMIN)) {
1755                 status = -EPERM;
1756                 goto out_notask;
1757         }
1758
1759         inode = dentry->d_inode;
1760         task = get_proc_task(inode);
1761         if (!task)
1762                 goto out_notask;
1763
1764         mm = mm_access(task, PTRACE_MODE_READ);
1765         if (IS_ERR_OR_NULL(mm))
1766                 goto out;
1767
1768         if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
1769                 down_read(&mm->mmap_sem);
1770                 exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
1771                 up_read(&mm->mmap_sem);
1772         }
1773
1774         mmput(mm);
1775
1776         if (exact_vma_exists) {
1777                 if (task_dumpable(task)) {
1778                         rcu_read_lock();
1779                         cred = __task_cred(task);
1780                         inode->i_uid = cred->euid;
1781                         inode->i_gid = cred->egid;
1782                         rcu_read_unlock();
1783                 } else {
1784                         inode->i_uid = GLOBAL_ROOT_UID;
1785                         inode->i_gid = GLOBAL_ROOT_GID;
1786                 }
1787                 security_task_to_inode(task, inode);
1788                 status = 1;
1789         }
1790
1791 out:
1792         put_task_struct(task);
1793
1794 out_notask:
1795         if (status <= 0)
1796                 d_drop(dentry);
1797
1798         return status;
1799 }
1800
1801 static const struct dentry_operations tid_map_files_dentry_operations = {
1802         .d_revalidate   = map_files_d_revalidate,
1803         .d_delete       = pid_delete_dentry,
1804 };
1805
1806 static int proc_map_files_get_link(struct dentry *dentry, struct path *path)
1807 {
1808         unsigned long vm_start, vm_end;
1809         struct vm_area_struct *vma;
1810         struct task_struct *task;
1811         struct mm_struct *mm;
1812         int rc;
1813
1814         rc = -ENOENT;
1815         task = get_proc_task(dentry->d_inode);
1816         if (!task)
1817                 goto out;
1818
1819         mm = get_task_mm(task);
1820         put_task_struct(task);
1821         if (!mm)
1822                 goto out;
1823
1824         rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
1825         if (rc)
1826                 goto out_mmput;
1827
1828         down_read(&mm->mmap_sem);
1829         vma = find_exact_vma(mm, vm_start, vm_end);
1830         if (vma && vma->vm_file) {
1831                 *path = vma->vm_file->f_path;
1832                 path_get(path);
1833                 rc = 0;
1834         }
1835         up_read(&mm->mmap_sem);
1836
1837 out_mmput:
1838         mmput(mm);
1839 out:
1840         return rc;
1841 }
1842
1843 struct map_files_info {
1844         fmode_t         mode;
1845         unsigned long   len;
1846         unsigned char   name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
1847 };
1848
1849 static struct dentry *
1850 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
1851                            struct task_struct *task, const void *ptr)
1852 {
1853         fmode_t mode = (fmode_t)(unsigned long)ptr;
1854         struct proc_inode *ei;
1855         struct inode *inode;
1856
1857         inode = proc_pid_make_inode(dir->i_sb, task);
1858         if (!inode)
1859                 return ERR_PTR(-ENOENT);
1860
1861         ei = PROC_I(inode);
1862         ei->op.proc_get_link = proc_map_files_get_link;
1863
1864         inode->i_op = &proc_pid_link_inode_operations;
1865         inode->i_size = 64;
1866         inode->i_mode = S_IFLNK;
1867
1868         if (mode & FMODE_READ)
1869                 inode->i_mode |= S_IRUSR;
1870         if (mode & FMODE_WRITE)
1871                 inode->i_mode |= S_IWUSR;
1872
1873         d_set_d_op(dentry, &tid_map_files_dentry_operations);
1874         d_add(dentry, inode);
1875
1876         return NULL;
1877 }
1878
1879 static struct dentry *proc_map_files_lookup(struct inode *dir,
1880                 struct dentry *dentry, unsigned int flags)
1881 {
1882         unsigned long vm_start, vm_end;
1883         struct vm_area_struct *vma;
1884         struct task_struct *task;
1885         struct dentry *result;
1886         struct mm_struct *mm;
1887
1888         result = ERR_PTR(-EPERM);
1889         if (!capable(CAP_SYS_ADMIN))
1890                 goto out;
1891
1892         result = ERR_PTR(-ENOENT);
1893         task = get_proc_task(dir);
1894         if (!task)
1895                 goto out;
1896
1897         result = ERR_PTR(-EACCES);
1898         if (!ptrace_may_access(task, PTRACE_MODE_READ))
1899                 goto out_put_task;
1900
1901         result = ERR_PTR(-ENOENT);
1902         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
1903                 goto out_put_task;
1904
1905         mm = get_task_mm(task);
1906         if (!mm)
1907                 goto out_put_task;
1908
1909         down_read(&mm->mmap_sem);
1910         vma = find_exact_vma(mm, vm_start, vm_end);
1911         if (!vma)
1912                 goto out_no_vma;
1913
1914         if (vma->vm_file)
1915                 result = proc_map_files_instantiate(dir, dentry, task,
1916                                 (void *)(unsigned long)vma->vm_file->f_mode);
1917
1918 out_no_vma:
1919         up_read(&mm->mmap_sem);
1920         mmput(mm);
1921 out_put_task:
1922         put_task_struct(task);
1923 out:
1924         return result;
1925 }
1926
1927 static const struct inode_operations proc_map_files_inode_operations = {
1928         .lookup         = proc_map_files_lookup,
1929         .permission     = proc_fd_permission,
1930         .setattr        = proc_setattr,
1931 };
1932
1933 static int
1934 proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
1935 {
1936         struct dentry *dentry = filp->f_path.dentry;
1937         struct inode *inode = dentry->d_inode;
1938         struct vm_area_struct *vma;
1939         struct task_struct *task;
1940         struct mm_struct *mm;
1941         ino_t ino;
1942         int ret;
1943
1944         ret = -EPERM;
1945         if (!capable(CAP_SYS_ADMIN))
1946                 goto out;
1947
1948         ret = -ENOENT;
1949         task = get_proc_task(inode);
1950         if (!task)
1951                 goto out;
1952
1953         ret = -EACCES;
1954         if (!ptrace_may_access(task, PTRACE_MODE_READ))
1955                 goto out_put_task;
1956
1957         ret = 0;
1958         switch (filp->f_pos) {
1959         case 0:
1960                 ino = inode->i_ino;
1961                 if (filldir(dirent, ".", 1, 0, ino, DT_DIR) < 0)
1962                         goto out_put_task;
1963                 filp->f_pos++;
1964         case 1:
1965                 ino = parent_ino(dentry);
1966                 if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1967                         goto out_put_task;
1968                 filp->f_pos++;
1969         default:
1970         {
1971                 unsigned long nr_files, pos, i;
1972                 struct flex_array *fa = NULL;
1973                 struct map_files_info info;
1974                 struct map_files_info *p;
1975
1976                 mm = get_task_mm(task);
1977                 if (!mm)
1978                         goto out_put_task;
1979                 down_read(&mm->mmap_sem);
1980
1981                 nr_files = 0;
1982
1983                 /*
1984                  * We need two passes here:
1985                  *
1986                  *  1) Collect vmas of mapped files with mmap_sem taken
1987                  *  2) Release mmap_sem and instantiate entries
1988                  *
1989                  * otherwise we get lockdep complained, since filldir()
1990                  * routine might require mmap_sem taken in might_fault().
1991                  */
1992
1993                 for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
1994                         if (vma->vm_file && ++pos > filp->f_pos)
1995                                 nr_files++;
1996                 }
1997
1998                 if (nr_files) {
1999                         fa = flex_array_alloc(sizeof(info), nr_files,
2000                                                 GFP_KERNEL);
2001                         if (!fa || flex_array_prealloc(fa, 0, nr_files,
2002                                                         GFP_KERNEL)) {
2003                                 ret = -ENOMEM;
2004                                 if (fa)
2005                                         flex_array_free(fa);
2006                                 up_read(&mm->mmap_sem);
2007                                 mmput(mm);
2008                                 goto out_put_task;
2009                         }
2010                         for (i = 0, vma = mm->mmap, pos = 2; vma;
2011                                         vma = vma->vm_next) {
2012                                 if (!vma->vm_file)
2013                                         continue;
2014                                 if (++pos <= filp->f_pos)
2015                                         continue;
2016
2017                                 info.mode = vma->vm_file->f_mode;
2018                                 info.len = snprintf(info.name,
2019                                                 sizeof(info.name), "%lx-%lx",
2020                                                 vma->vm_start, vma->vm_end);
2021                                 if (flex_array_put(fa, i++, &info, GFP_KERNEL))
2022                                         BUG();
2023                         }
2024                 }
2025                 up_read(&mm->mmap_sem);
2026
2027                 for (i = 0; i < nr_files; i++) {
2028                         p = flex_array_get(fa, i);
2029                         ret = proc_fill_cache(filp, dirent, filldir,
2030                                               p->name, p->len,
2031                                               proc_map_files_instantiate,
2032                                               task,
2033                                               (void *)(unsigned long)p->mode);
2034                         if (ret)
2035                                 break;
2036                         filp->f_pos++;
2037                 }
2038                 if (fa)
2039                         flex_array_free(fa);
2040                 mmput(mm);
2041         }
2042         }
2043
2044 out_put_task:
2045         put_task_struct(task);
2046 out:
2047         return ret;
2048 }
2049
2050 static const struct file_operations proc_map_files_operations = {
2051         .read           = generic_read_dir,
2052         .readdir        = proc_map_files_readdir,
2053         .llseek         = default_llseek,
2054 };
2055
2056 struct timers_private {
2057         struct pid *pid;
2058         struct task_struct *task;
2059         struct sighand_struct *sighand;
2060         struct pid_namespace *ns;
2061         unsigned long flags;
2062 };
2063
2064 static void *timers_start(struct seq_file *m, loff_t *pos)
2065 {
2066         struct timers_private *tp = m->private;
2067
2068         tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
2069         if (!tp->task)
2070                 return ERR_PTR(-ESRCH);
2071
2072         tp->sighand = lock_task_sighand(tp->task, &tp->flags);
2073         if (!tp->sighand)
2074                 return ERR_PTR(-ESRCH);
2075
2076         return seq_list_start(&tp->task->signal->posix_timers, *pos);
2077 }
2078
2079 static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
2080 {
2081         struct timers_private *tp = m->private;
2082         return seq_list_next(v, &tp->task->signal->posix_timers, pos);
2083 }
2084
2085 static void timers_stop(struct seq_file *m, void *v)
2086 {
2087         struct timers_private *tp = m->private;
2088
2089         if (tp->sighand) {
2090                 unlock_task_sighand(tp->task, &tp->flags);
2091                 tp->sighand = NULL;
2092         }
2093
2094         if (tp->task) {
2095                 put_task_struct(tp->task);
2096                 tp->task = NULL;
2097         }
2098 }
2099
2100 static int show_timer(struct seq_file *m, void *v)
2101 {
2102         struct k_itimer *timer;
2103         struct timers_private *tp = m->private;
2104         int notify;
2105         static char *nstr[] = {
2106                 [SIGEV_SIGNAL] = "signal",
2107                 [SIGEV_NONE] = "none",
2108                 [SIGEV_THREAD] = "thread",
2109         };
2110
2111         timer = list_entry((struct list_head *)v, struct k_itimer, list);
2112         notify = timer->it_sigev_notify;
2113
2114         seq_printf(m, "ID: %d\n", timer->it_id);
2115         seq_printf(m, "signal: %d/%p\n", timer->sigq->info.si_signo,
2116                         timer->sigq->info.si_value.sival_ptr);
2117         seq_printf(m, "notify: %s/%s.%d\n",
2118                 nstr[notify & ~SIGEV_THREAD_ID],
2119                 (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
2120                 pid_nr_ns(timer->it_pid, tp->ns));
2121         seq_printf(m, "ClockID: %d\n", timer->it_clock);
2122
2123         return 0;
2124 }
2125
2126 static const struct seq_operations proc_timers_seq_ops = {
2127         .start  = timers_start,
2128         .next   = timers_next,
2129         .stop   = timers_stop,
2130         .show   = show_timer,
2131 };
2132
2133 static int proc_timers_open(struct inode *inode, struct file *file)
2134 {
2135         struct timers_private *tp;
2136
2137         tp = __seq_open_private(file, &proc_timers_seq_ops,
2138                         sizeof(struct timers_private));
2139         if (!tp)
2140                 return -ENOMEM;
2141
2142         tp->pid = proc_pid(inode);
2143         tp->ns = inode->i_sb->s_fs_info;
2144         return 0;
2145 }
2146
2147 static const struct file_operations proc_timers_operations = {
2148         .open           = proc_timers_open,
2149         .read           = seq_read,
2150         .llseek         = seq_lseek,
2151         .release        = seq_release_private,
2152 };
2153 #endif /* CONFIG_CHECKPOINT_RESTORE */
2154
2155 static struct dentry *proc_pident_instantiate(struct inode *dir,
2156         struct dentry *dentry, struct task_struct *task, const void *ptr)
2157 {
2158         const struct pid_entry *p = ptr;
2159         struct inode *inode;
2160         struct proc_inode *ei;
2161         struct dentry *error = ERR_PTR(-ENOENT);
2162
2163         inode = proc_pid_make_inode(dir->i_sb, task);
2164         if (!inode)
2165                 goto out;
2166
2167         ei = PROC_I(inode);
2168         inode->i_mode = p->mode;
2169         if (S_ISDIR(inode->i_mode))
2170                 set_nlink(inode, 2);    /* Use getattr to fix if necessary */
2171         if (p->iop)
2172                 inode->i_op = p->iop;
2173         if (p->fop)
2174                 inode->i_fop = p->fop;
2175         ei->op = p->op;
2176         d_set_d_op(dentry, &pid_dentry_operations);
2177         d_add(dentry, inode);
2178         /* Close the race of the process dying before we return the dentry */
2179         if (pid_revalidate(dentry, 0))
2180                 error = NULL;
2181 out:
2182         return error;
2183 }
2184
2185 static struct dentry *proc_pident_lookup(struct inode *dir, 
2186                                          struct dentry *dentry,
2187                                          const struct pid_entry *ents,
2188                                          unsigned int nents)
2189 {
2190         struct dentry *error;
2191         struct task_struct *task = get_proc_task(dir);
2192         const struct pid_entry *p, *last;
2193
2194         error = ERR_PTR(-ENOENT);
2195
2196         if (!task)
2197                 goto out_no_task;
2198
2199         /*
2200          * Yes, it does not scale. And it should not. Don't add
2201          * new entries into /proc/<tgid>/ without very good reasons.
2202          */
2203         last = &ents[nents - 1];
2204         for (p = ents; p <= last; p++) {
2205                 if (p->len != dentry->d_name.len)
2206                         continue;
2207                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2208                         break;
2209         }
2210         if (p > last)
2211                 goto out;
2212
2213         error = proc_pident_instantiate(dir, dentry, task, p);
2214 out:
2215         put_task_struct(task);
2216 out_no_task:
2217         return error;
2218 }
2219
2220 static int proc_pident_fill_cache(struct file *filp, void *dirent,
2221         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2222 {
2223         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2224                                 proc_pident_instantiate, task, p);
2225 }
2226
2227 static int proc_pident_readdir(struct file *filp,
2228                 void *dirent, filldir_t filldir,
2229                 const struct pid_entry *ents, unsigned int nents)
2230 {
2231         int i;
2232         struct dentry *dentry = filp->f_path.dentry;
2233         struct inode *inode = dentry->d_inode;
2234         struct task_struct *task = get_proc_task(inode);
2235         const struct pid_entry *p, *last;
2236         ino_t ino;
2237         int ret;
2238
2239         ret = -ENOENT;
2240         if (!task)
2241                 goto out_no_task;
2242
2243         ret = 0;
2244         i = filp->f_pos;
2245         switch (i) {
2246         case 0:
2247                 ino = inode->i_ino;
2248                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2249                         goto out;
2250                 i++;
2251                 filp->f_pos++;
2252                 /* fall through */
2253         case 1:
2254                 ino = parent_ino(dentry);
2255                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2256                         goto out;
2257                 i++;
2258                 filp->f_pos++;
2259                 /* fall through */
2260         default:
2261                 i -= 2;
2262                 if (i >= nents) {
2263                         ret = 1;
2264                         goto out;
2265                 }
2266                 p = ents + i;
2267                 last = &ents[nents - 1];
2268                 while (p <= last) {
2269                         if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2270                                 goto out;
2271                         filp->f_pos++;
2272                         p++;
2273                 }
2274         }
2275
2276         ret = 1;
2277 out:
2278         put_task_struct(task);
2279 out_no_task:
2280         return ret;
2281 }
2282
2283 #ifdef CONFIG_SECURITY
2284 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2285                                   size_t count, loff_t *ppos)
2286 {
2287         struct inode * inode = file_inode(file);
2288         char *p = NULL;
2289         ssize_t length;
2290         struct task_struct *task = get_proc_task(inode);
2291
2292         if (!task)
2293                 return -ESRCH;
2294
2295         length = security_getprocattr(task,
2296                                       (char*)file->f_path.dentry->d_name.name,
2297                                       &p);
2298         put_task_struct(task);
2299         if (length > 0)
2300                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2301         kfree(p);
2302         return length;
2303 }
2304
2305 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2306                                    size_t count, loff_t *ppos)
2307 {
2308         struct inode * inode = file_inode(file);
2309         char *page;
2310         ssize_t length;
2311         struct task_struct *task = get_proc_task(inode);
2312
2313         length = -ESRCH;
2314         if (!task)
2315                 goto out_no_task;
2316         if (count > PAGE_SIZE)
2317                 count = PAGE_SIZE;
2318
2319         /* No partial writes. */
2320         length = -EINVAL;
2321         if (*ppos != 0)
2322                 goto out;
2323
2324         length = -ENOMEM;
2325         page = (char*)__get_free_page(GFP_TEMPORARY);
2326         if (!page)
2327                 goto out;
2328
2329         length = -EFAULT;
2330         if (copy_from_user(page, buf, count))
2331                 goto out_free;
2332
2333         /* Guard against adverse ptrace interaction */
2334         length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2335         if (length < 0)
2336                 goto out_free;
2337
2338         length = security_setprocattr(task,
2339                                       (char*)file->f_path.dentry->d_name.name,
2340                                       (void*)page, count);
2341         mutex_unlock(&task->signal->cred_guard_mutex);
2342 out_free:
2343         free_page((unsigned long) page);
2344 out:
2345         put_task_struct(task);
2346 out_no_task:
2347         return length;
2348 }
2349
2350 static const struct file_operations proc_pid_attr_operations = {
2351         .read           = proc_pid_attr_read,
2352         .write          = proc_pid_attr_write,
2353         .llseek         = generic_file_llseek,
2354 };
2355
2356 static const struct pid_entry attr_dir_stuff[] = {
2357         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2358         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2359         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2360         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2361         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2362         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2363 };
2364
2365 static int proc_attr_dir_readdir(struct file * filp,
2366                              void * dirent, filldir_t filldir)
2367 {
2368         return proc_pident_readdir(filp,dirent,filldir,
2369                                    attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2370 }
2371
2372 static const struct file_operations proc_attr_dir_operations = {
2373         .read           = generic_read_dir,
2374         .readdir        = proc_attr_dir_readdir,
2375         .llseek         = default_llseek,
2376 };
2377
2378 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2379                                 struct dentry *dentry, unsigned int flags)
2380 {
2381         return proc_pident_lookup(dir, dentry,
2382                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2383 }
2384
2385 static const struct inode_operations proc_attr_dir_inode_operations = {
2386         .lookup         = proc_attr_dir_lookup,
2387         .getattr        = pid_getattr,
2388         .setattr        = proc_setattr,
2389 };
2390
2391 #endif
2392
2393 #ifdef CONFIG_ELF_CORE
2394 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2395                                          size_t count, loff_t *ppos)
2396 {
2397         struct task_struct *task = get_proc_task(file_inode(file));
2398         struct mm_struct *mm;
2399         char buffer[PROC_NUMBUF];
2400         size_t len;
2401         int ret;
2402
2403         if (!task)
2404                 return -ESRCH;
2405
2406         ret = 0;
2407         mm = get_task_mm(task);
2408         if (mm) {
2409                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2410                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2411                                 MMF_DUMP_FILTER_SHIFT));
2412                 mmput(mm);
2413                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2414         }
2415
2416         put_task_struct(task);
2417
2418         return ret;
2419 }
2420
2421 static ssize_t proc_coredump_filter_write(struct file *file,
2422                                           const char __user *buf,
2423                                           size_t count,
2424                                           loff_t *ppos)
2425 {
2426         struct task_struct *task;
2427         struct mm_struct *mm;
2428         char buffer[PROC_NUMBUF], *end;
2429         unsigned int val;
2430         int ret;
2431         int i;
2432         unsigned long mask;
2433
2434         ret = -EFAULT;
2435         memset(buffer, 0, sizeof(buffer));
2436         if (count > sizeof(buffer) - 1)
2437                 count = sizeof(buffer) - 1;
2438         if (copy_from_user(buffer, buf, count))
2439                 goto out_no_task;
2440
2441         ret = -EINVAL;
2442         val = (unsigned int)simple_strtoul(buffer, &end, 0);
2443         if (*end == '\n')
2444                 end++;
2445         if (end - buffer == 0)
2446                 goto out_no_task;
2447
2448         ret = -ESRCH;
2449         task = get_proc_task(file_inode(file));
2450         if (!task)
2451                 goto out_no_task;
2452
2453         ret = end - buffer;
2454         mm = get_task_mm(task);
2455         if (!mm)
2456                 goto out_no_mm;
2457
2458         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2459                 if (val & mask)
2460                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2461                 else
2462                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2463         }
2464
2465         mmput(mm);
2466  out_no_mm:
2467         put_task_struct(task);
2468  out_no_task:
2469         return ret;
2470 }
2471
2472 static const struct file_operations proc_coredump_filter_operations = {
2473         .read           = proc_coredump_filter_read,
2474         .write          = proc_coredump_filter_write,
2475         .llseek         = generic_file_llseek,
2476 };
2477 #endif
2478
2479 #ifdef CONFIG_TASK_IO_ACCOUNTING
2480 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2481 {
2482         struct task_io_accounting acct = task->ioac;
2483         unsigned long flags;
2484         int result;
2485
2486         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2487         if (result)
2488                 return result;
2489
2490         if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
2491                 result = -EACCES;
2492                 goto out_unlock;
2493         }
2494
2495         if (whole && lock_task_sighand(task, &flags)) {
2496                 struct task_struct *t = task;
2497
2498                 task_io_accounting_add(&acct, &task->signal->ioac);
2499                 while_each_thread(task, t)
2500                         task_io_accounting_add(&acct, &t->ioac);
2501
2502                 unlock_task_sighand(task, &flags);
2503         }
2504         result = sprintf(buffer,
2505                         "rchar: %llu\n"
2506                         "wchar: %llu\n"
2507                         "syscr: %llu\n"
2508                         "syscw: %llu\n"
2509                         "read_bytes: %llu\n"
2510                         "write_bytes: %llu\n"
2511                         "cancelled_write_bytes: %llu\n",
2512                         (unsigned long long)acct.rchar,
2513                         (unsigned long long)acct.wchar,
2514                         (unsigned long long)acct.syscr,
2515                         (unsigned long long)acct.syscw,
2516                         (unsigned long long)acct.read_bytes,
2517                         (unsigned long long)acct.write_bytes,
2518                         (unsigned long long)acct.cancelled_write_bytes);
2519 out_unlock:
2520         mutex_unlock(&task->signal->cred_guard_mutex);
2521         return result;
2522 }
2523
2524 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2525 {
2526         return do_io_accounting(task, buffer, 0);
2527 }
2528
2529 static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2530 {
2531         return do_io_accounting(task, buffer, 1);
2532 }
2533 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2534
2535 #ifdef CONFIG_USER_NS
2536 static int proc_id_map_open(struct inode *inode, struct file *file,
2537         struct seq_operations *seq_ops)
2538 {
2539         struct user_namespace *ns = NULL;
2540         struct task_struct *task;
2541         struct seq_file *seq;
2542         int ret = -EINVAL;
2543
2544         task = get_proc_task(inode);
2545         if (task) {
2546                 rcu_read_lock();
2547                 ns = get_user_ns(task_cred_xxx(task, user_ns));
2548                 rcu_read_unlock();
2549                 put_task_struct(task);
2550         }
2551         if (!ns)
2552                 goto err;
2553
2554         ret = seq_open(file, seq_ops);
2555         if (ret)
2556                 goto err_put_ns;
2557
2558         seq = file->private_data;
2559         seq->private = ns;
2560
2561         return 0;
2562 err_put_ns:
2563         put_user_ns(ns);
2564 err:
2565         return ret;
2566 }
2567
2568 static int proc_id_map_release(struct inode *inode, struct file *file)
2569 {
2570         struct seq_file *seq = file->private_data;
2571         struct user_namespace *ns = seq->private;
2572         put_user_ns(ns);
2573         return seq_release(inode, file);
2574 }
2575
2576 static int proc_uid_map_open(struct inode *inode, struct file *file)
2577 {
2578         return proc_id_map_open(inode, file, &proc_uid_seq_operations);
2579 }
2580
2581 static int proc_gid_map_open(struct inode *inode, struct file *file)
2582 {
2583         return proc_id_map_open(inode, file, &proc_gid_seq_operations);
2584 }
2585
2586 static int proc_projid_map_open(struct inode *inode, struct file *file)
2587 {
2588         return proc_id_map_open(inode, file, &proc_projid_seq_operations);
2589 }
2590
2591 static const struct file_operations proc_uid_map_operations = {
2592         .open           = proc_uid_map_open,
2593         .write          = proc_uid_map_write,
2594         .read           = seq_read,
2595         .llseek         = seq_lseek,
2596         .release        = proc_id_map_release,
2597 };
2598
2599 static const struct file_operations proc_gid_map_operations = {
2600         .open           = proc_gid_map_open,
2601         .write          = proc_gid_map_write,
2602         .read           = seq_read,
2603         .llseek         = seq_lseek,
2604         .release        = proc_id_map_release,
2605 };
2606
2607 static const struct file_operations proc_projid_map_operations = {
2608         .open           = proc_projid_map_open,
2609         .write          = proc_projid_map_write,
2610         .read           = seq_read,
2611         .llseek         = seq_lseek,
2612         .release        = proc_id_map_release,
2613 };
2614 #endif /* CONFIG_USER_NS */
2615
2616 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2617                                 struct pid *pid, struct task_struct *task)
2618 {
2619         int err = lock_trace(task);
2620         if (!err) {
2621                 seq_printf(m, "%08x\n", task->personality);
2622                 unlock_trace(task);
2623         }
2624         return err;
2625 }
2626
2627 /*
2628  * Thread groups
2629  */
2630 static const struct file_operations proc_task_operations;
2631 static const struct inode_operations proc_task_inode_operations;
2632
2633 static const struct pid_entry tgid_base_stuff[] = {
2634         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2635         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2636 #ifdef CONFIG_CHECKPOINT_RESTORE
2637         DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
2638 #endif
2639         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2640         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2641 #ifdef CONFIG_NET
2642         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2643 #endif
2644         REG("environ",    S_IRUSR, proc_environ_operations),
2645         INF("auxv",       S_IRUSR, proc_pid_auxv),
2646         ONE("status",     S_IRUGO, proc_pid_status),
2647         ONE("personality", S_IRUGO, proc_pid_personality),
2648         INF("limits",     S_IRUGO, proc_pid_limits),
2649 #ifdef CONFIG_SCHED_DEBUG
2650         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2651 #endif
2652 #ifdef CONFIG_SCHED_AUTOGROUP
2653         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2654 #endif
2655         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2656 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2657         INF("syscall",    S_IRUGO, proc_pid_syscall),
2658 #endif
2659         INF("cmdline",    S_IRUGO, proc_pid_cmdline),
2660         ONE("stat",       S_IRUGO, proc_tgid_stat),
2661         ONE("statm",      S_IRUGO, proc_pid_statm),
2662         REG("maps",       S_IRUGO, proc_pid_maps_operations),
2663 #ifdef CONFIG_NUMA
2664         REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
2665 #endif
2666         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2667         LNK("cwd",        proc_cwd_link),
2668         LNK("root",       proc_root_link),
2669         LNK("exe",        proc_exe_link),
2670         REG("mounts",     S_IRUGO, proc_mounts_operations),
2671         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2672         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2673 #ifdef CONFIG_PROC_PAGE_MONITOR
2674         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2675         REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
2676         REG("pagemap",    S_IRUGO, proc_pagemap_operations),
2677 #endif
2678 #ifdef CONFIG_SECURITY
2679         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2680 #endif
2681 #ifdef CONFIG_KALLSYMS
2682         INF("wchan",      S_IRUGO, proc_pid_wchan),
2683 #endif
2684 #ifdef CONFIG_STACKTRACE
2685         ONE("stack",      S_IRUGO, proc_pid_stack),
2686 #endif
2687 #ifdef CONFIG_SCHEDSTATS
2688         INF("schedstat",  S_IRUGO, proc_pid_schedstat),
2689 #endif
2690 #ifdef CONFIG_LATENCYTOP
2691         REG("latency",  S_IRUGO, proc_lstats_operations),
2692 #endif
2693 #ifdef CONFIG_PROC_PID_CPUSET
2694         REG("cpuset",     S_IRUGO, proc_cpuset_operations),
2695 #endif
2696 #ifdef CONFIG_CGROUPS
2697         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2698 #endif
2699         INF("oom_score",  S_IRUGO, proc_oom_score),
2700         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
2701         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2702 #ifdef CONFIG_AUDITSYSCALL
2703         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2704         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2705 #endif
2706 #ifdef CONFIG_FAULT_INJECTION
2707         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2708 #endif
2709 #ifdef CONFIG_ELF_CORE
2710         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2711 #endif
2712 #ifdef CONFIG_TASK_IO_ACCOUNTING
2713         INF("io",       S_IRUSR, proc_tgid_io_accounting),
2714 #endif
2715 #ifdef CONFIG_HARDWALL
2716         INF("hardwall",   S_IRUGO, proc_pid_hardwall),
2717 #endif
2718 #ifdef CONFIG_USER_NS
2719         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
2720         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
2721         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
2722 #endif
2723 #ifdef CONFIG_CHECKPOINT_RESTORE
2724         REG("timers",     S_IRUGO, proc_timers_operations),
2725 #endif
2726 };
2727
2728 static int proc_tgid_base_readdir(struct file * filp,
2729                              void * dirent, filldir_t filldir)
2730 {
2731         return proc_pident_readdir(filp,dirent,filldir,
2732                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2733 }
2734
2735 static const struct file_operations proc_tgid_base_operations = {
2736         .read           = generic_read_dir,
2737         .readdir        = proc_tgid_base_readdir,
2738         .llseek         = default_llseek,
2739 };
2740
2741 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
2742 {
2743         return proc_pident_lookup(dir, dentry,
2744                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2745 }
2746
2747 static const struct inode_operations proc_tgid_base_inode_operations = {
2748         .lookup         = proc_tgid_base_lookup,
2749         .getattr        = pid_getattr,
2750         .setattr        = proc_setattr,
2751         .permission     = proc_pid_permission,
2752 };
2753
2754 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2755 {
2756         struct dentry *dentry, *leader, *dir;
2757         char buf[PROC_NUMBUF];
2758         struct qstr name;
2759
2760         name.name = buf;
2761         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2762         /* no ->d_hash() rejects on procfs */
2763         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2764         if (dentry) {
2765                 shrink_dcache_parent(dentry);
2766                 d_drop(dentry);
2767                 dput(dentry);
2768         }
2769
2770         name.name = buf;
2771         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2772         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2773         if (!leader)
2774                 goto out;
2775
2776         name.name = "task";
2777         name.len = strlen(name.name);
2778         dir = d_hash_and_lookup(leader, &name);
2779         if (!dir)
2780                 goto out_put_leader;
2781
2782         name.name = buf;
2783         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2784         dentry = d_hash_and_lookup(dir, &name);
2785         if (dentry) {
2786                 shrink_dcache_parent(dentry);
2787                 d_drop(dentry);
2788                 dput(dentry);
2789         }
2790
2791         dput(dir);
2792 out_put_leader:
2793         dput(leader);
2794 out:
2795         return;
2796 }
2797
2798 /**
2799  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2800  * @task: task that should be flushed.
2801  *
2802  * When flushing dentries from proc, one needs to flush them from global
2803  * proc (proc_mnt) and from all the namespaces' procs this task was seen
2804  * in. This call is supposed to do all of this job.
2805  *
2806  * Looks in the dcache for
2807  * /proc/@pid
2808  * /proc/@tgid/task/@pid
2809  * if either directory is present flushes it and all of it'ts children
2810  * from the dcache.
2811  *
2812  * It is safe and reasonable to cache /proc entries for a task until
2813  * that task exits.  After that they just clog up the dcache with
2814  * useless entries, possibly causing useful dcache entries to be
2815  * flushed instead.  This routine is proved to flush those useless
2816  * dcache entries at process exit time.
2817  *
2818  * NOTE: This routine is just an optimization so it does not guarantee
2819  *       that no dcache entries will exist at process exit time it
2820  *       just makes it very unlikely that any will persist.
2821  */
2822
2823 void proc_flush_task(struct task_struct *task)
2824 {
2825         int i;
2826         struct pid *pid, *tgid;
2827         struct upid *upid;
2828
2829         pid = task_pid(task);
2830         tgid = task_tgid(task);
2831
2832         for (i = 0; i <= pid->level; i++) {
2833                 upid = &pid->numbers[i];
2834                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2835                                         tgid->numbers[i].nr);
2836         }
2837 }
2838
2839 static struct dentry *proc_pid_instantiate(struct inode *dir,
2840                                            struct dentry * dentry,
2841                                            struct task_struct *task, const void *ptr)
2842 {
2843         struct dentry *error = ERR_PTR(-ENOENT);
2844         struct inode *inode;
2845
2846         inode = proc_pid_make_inode(dir->i_sb, task);
2847         if (!inode)
2848                 goto out;
2849
2850         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2851         inode->i_op = &proc_tgid_base_inode_operations;
2852         inode->i_fop = &proc_tgid_base_operations;
2853         inode->i_flags|=S_IMMUTABLE;
2854
2855         set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
2856                                                   ARRAY_SIZE(tgid_base_stuff)));
2857
2858         d_set_d_op(dentry, &pid_dentry_operations);
2859
2860         d_add(dentry, inode);
2861         /* Close the race of the process dying before we return the dentry */
2862         if (pid_revalidate(dentry, 0))
2863                 error = NULL;
2864 out:
2865         return error;
2866 }
2867
2868 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
2869 {
2870         struct dentry *result = NULL;
2871         struct task_struct *task;
2872         unsigned tgid;
2873         struct pid_namespace *ns;
2874
2875         tgid = name_to_int(dentry);
2876         if (tgid == ~0U)
2877                 goto out;
2878
2879         ns = dentry->d_sb->s_fs_info;
2880         rcu_read_lock();
2881         task = find_task_by_pid_ns(tgid, ns);
2882         if (task)
2883                 get_task_struct(task);
2884         rcu_read_unlock();
2885         if (!task)
2886                 goto out;
2887
2888         result = proc_pid_instantiate(dir, dentry, task, NULL);
2889         put_task_struct(task);
2890 out:
2891         return result;
2892 }
2893
2894 /*
2895  * Find the first task with tgid >= tgid
2896  *
2897  */
2898 struct tgid_iter {
2899         unsigned int tgid;
2900         struct task_struct *task;
2901 };
2902 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
2903 {
2904         struct pid *pid;
2905
2906         if (iter.task)
2907                 put_task_struct(iter.task);
2908         rcu_read_lock();
2909 retry:
2910         iter.task = NULL;
2911         pid = find_ge_pid(iter.tgid, ns);
2912         if (pid) {
2913                 iter.tgid = pid_nr_ns(pid, ns);
2914                 iter.task = pid_task(pid, PIDTYPE_PID);
2915                 /* What we to know is if the pid we have find is the
2916                  * pid of a thread_group_leader.  Testing for task
2917                  * being a thread_group_leader is the obvious thing
2918                  * todo but there is a window when it fails, due to
2919                  * the pid transfer logic in de_thread.
2920                  *
2921                  * So we perform the straight forward test of seeing
2922                  * if the pid we have found is the pid of a thread
2923                  * group leader, and don't worry if the task we have
2924                  * found doesn't happen to be a thread group leader.
2925                  * As we don't care in the case of readdir.
2926                  */
2927                 if (!iter.task || !has_group_leader_pid(iter.task)) {
2928                         iter.tgid += 1;
2929                         goto retry;
2930                 }
2931                 get_task_struct(iter.task);
2932         }
2933         rcu_read_unlock();
2934         return iter;
2935 }
2936
2937 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 1)
2938
2939 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
2940         struct tgid_iter iter)
2941 {
2942         char name[PROC_NUMBUF];
2943         int len = snprintf(name, sizeof(name), "%d", iter.tgid);
2944         return proc_fill_cache(filp, dirent, filldir, name, len,
2945                                 proc_pid_instantiate, iter.task, NULL);
2946 }
2947
2948 static int fake_filldir(void *buf, const char *name, int namelen,
2949                         loff_t offset, u64 ino, unsigned d_type)
2950 {
2951         return 0;
2952 }
2953
2954 /* for the /proc/ directory itself, after non-process stuff has been done */
2955 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2956 {
2957         struct tgid_iter iter;
2958         struct pid_namespace *ns;
2959         filldir_t __filldir;
2960         loff_t pos = filp->f_pos;
2961
2962         if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
2963                 goto out;
2964
2965         if (pos == TGID_OFFSET - 1) {
2966                 if (proc_fill_cache(filp, dirent, filldir, "self", 4,
2967                                         NULL, NULL, NULL) < 0)
2968                         goto out;
2969                 iter.tgid = 0;
2970         } else {
2971                 iter.tgid = pos - TGID_OFFSET;
2972         }
2973         iter.task = NULL;
2974         ns = filp->f_dentry->d_sb->s_fs_info;
2975         for (iter = next_tgid(ns, iter);
2976              iter.task;
2977              iter.tgid += 1, iter = next_tgid(ns, iter)) {
2978                 if (has_pid_permissions(ns, iter.task, 2))
2979                         __filldir = filldir;
2980                 else
2981                         __filldir = fake_filldir;
2982
2983                 filp->f_pos = iter.tgid + TGID_OFFSET;
2984                 if (proc_pid_fill_cache(filp, dirent, __filldir, iter) < 0) {
2985                         put_task_struct(iter.task);
2986                         goto out;
2987                 }
2988         }
2989         filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
2990 out:
2991         return 0;
2992 }
2993
2994 /*
2995  * Tasks
2996  */
2997 static const struct pid_entry tid_base_stuff[] = {
2998         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2999         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3000         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3001         REG("environ",   S_IRUSR, proc_environ_operations),
3002         INF("auxv",      S_IRUSR, proc_pid_auxv),
3003         ONE("status",    S_IRUGO, proc_pid_status),
3004         ONE("personality", S_IRUGO, proc_pid_personality),
3005         INF("limits",    S_IRUGO, proc_pid_limits),
3006 #ifdef CONFIG_SCHED_DEBUG
3007         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3008 #endif
3009         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3010 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3011         INF("syscall",   S_IRUGO, proc_pid_syscall),
3012 #endif
3013         INF("cmdline",   S_IRUGO, proc_pid_cmdline),
3014         ONE("stat",      S_IRUGO, proc_tid_stat),
3015         ONE("statm",     S_IRUGO, proc_pid_statm),
3016         REG("maps",      S_IRUGO, proc_tid_maps_operations),
3017 #ifdef CONFIG_CHECKPOINT_RESTORE
3018         REG("children",  S_IRUGO, proc_tid_children_operations),
3019 #endif
3020 #ifdef CONFIG_NUMA
3021         REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations),
3022 #endif
3023         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3024         LNK("cwd",       proc_cwd_link),
3025         LNK("root",      proc_root_link),
3026         LNK("exe",       proc_exe_link),
3027         REG("mounts",    S_IRUGO, proc_mounts_operations),
3028         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3029 #ifdef CONFIG_PROC_PAGE_MONITOR
3030         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3031         REG("smaps",     S_IRUGO, proc_tid_smaps_operations),
3032         REG("pagemap",    S_IRUGO, proc_pagemap_operations),
3033 #endif
3034 #ifdef CONFIG_SECURITY
3035         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3036 #endif
3037 #ifdef CONFIG_KALLSYMS
3038         INF("wchan",     S_IRUGO, proc_pid_wchan),
3039 #endif
3040 #ifdef CONFIG_STACKTRACE
3041         ONE("stack",      S_IRUGO, proc_pid_stack),
3042 #endif
3043 #ifdef CONFIG_SCHEDSTATS
3044         INF("schedstat", S_IRUGO, proc_pid_schedstat),
3045 #endif
3046 #ifdef CONFIG_LATENCYTOP
3047         REG("latency",  S_IRUGO, proc_lstats_operations),
3048 #endif
3049 #ifdef CONFIG_PROC_PID_CPUSET
3050         REG("cpuset",    S_IRUGO, proc_cpuset_operations),
3051 #endif
3052 #ifdef CONFIG_CGROUPS
3053         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3054 #endif
3055         INF("oom_score", S_IRUGO, proc_oom_score),
3056         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
3057         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3058 #ifdef CONFIG_AUDITSYSCALL
3059         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3060         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3061 #endif
3062 #ifdef CONFIG_FAULT_INJECTION
3063         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3064 #endif
3065 #ifdef CONFIG_TASK_IO_ACCOUNTING
3066         INF("io",       S_IRUSR, proc_tid_io_accounting),
3067 #endif
3068 #ifdef CONFIG_HARDWALL
3069         INF("hardwall",   S_IRUGO, proc_pid_hardwall),
3070 #endif
3071 #ifdef CONFIG_USER_NS
3072         REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
3073         REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
3074         REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
3075 #endif
3076 };
3077
3078 static int proc_tid_base_readdir(struct file * filp,
3079                              void * dirent, filldir_t filldir)
3080 {
3081         return proc_pident_readdir(filp,dirent,filldir,
3082                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
3083 }
3084
3085 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
3086 {
3087         return proc_pident_lookup(dir, dentry,
3088                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3089 }
3090
3091 static const struct file_operations proc_tid_base_operations = {
3092         .read           = generic_read_dir,
3093         .readdir        = proc_tid_base_readdir,
3094         .llseek         = default_llseek,
3095 };
3096
3097 static const struct inode_operations proc_tid_base_inode_operations = {
3098         .lookup         = proc_tid_base_lookup,
3099         .getattr        = pid_getattr,
3100         .setattr        = proc_setattr,
3101 };
3102
3103 static struct dentry *proc_task_instantiate(struct inode *dir,
3104         struct dentry *dentry, struct task_struct *task, const void *ptr)
3105 {
3106         struct dentry *error = ERR_PTR(-ENOENT);
3107         struct inode *inode;
3108         inode = proc_pid_make_inode(dir->i_sb, task);
3109
3110         if (!inode)
3111                 goto out;
3112         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3113         inode->i_op = &proc_tid_base_inode_operations;
3114         inode->i_fop = &proc_tid_base_operations;
3115         inode->i_flags|=S_IMMUTABLE;
3116
3117         set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
3118                                                   ARRAY_SIZE(tid_base_stuff)));
3119
3120         d_set_d_op(dentry, &pid_dentry_operations);
3121
3122         d_add(dentry, inode);
3123         /* Close the race of the process dying before we return the dentry */
3124         if (pid_revalidate(dentry, 0))
3125                 error = NULL;
3126 out:
3127         return error;
3128 }
3129
3130 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
3131 {
3132         struct dentry *result = ERR_PTR(-ENOENT);
3133         struct task_struct *task;
3134         struct task_struct *leader = get_proc_task(dir);
3135         unsigned tid;
3136         struct pid_namespace *ns;
3137
3138         if (!leader)
3139                 goto out_no_task;
3140
3141         tid = name_to_int(dentry);
3142         if (tid == ~0U)
3143                 goto out;
3144
3145         ns = dentry->d_sb->s_fs_info;
3146         rcu_read_lock();
3147         task = find_task_by_pid_ns(tid, ns);
3148         if (task)
3149                 get_task_struct(task);
3150         rcu_read_unlock();
3151         if (!task)
3152                 goto out;
3153         if (!same_thread_group(leader, task))
3154                 goto out_drop_task;
3155
3156         result = proc_task_instantiate(dir, dentry, task, NULL);
3157 out_drop_task:
3158         put_task_struct(task);
3159 out:
3160         put_task_struct(leader);
3161 out_no_task:
3162         return result;
3163 }
3164
3165 /*
3166  * Find the first tid of a thread group to return to user space.
3167  *
3168  * Usually this is just the thread group leader, but if the users
3169  * buffer was too small or there was a seek into the middle of the
3170  * directory we have more work todo.
3171  *
3172  * In the case of a short read we start with find_task_by_pid.
3173  *
3174  * In the case of a seek we start with the leader and walk nr
3175  * threads past it.
3176  */
3177 static struct task_struct *first_tid(struct task_struct *leader,
3178                 int tid, int nr, struct pid_namespace *ns)
3179 {
3180         struct task_struct *pos;
3181
3182         rcu_read_lock();
3183         /* Attempt to start with the pid of a thread */
3184         if (tid && (nr > 0)) {
3185                 pos = find_task_by_pid_ns(tid, ns);
3186                 if (pos && (pos->group_leader == leader))
3187                         goto found;
3188         }
3189
3190         /* If nr exceeds the number of threads there is nothing todo */
3191         pos = NULL;
3192         if (nr && nr >= get_nr_threads(leader))
3193                 goto out;
3194
3195         /* If we haven't found our starting place yet start
3196          * with the leader and walk nr threads forward.
3197          */
3198         for (pos = leader; nr > 0; --nr) {
3199                 pos = next_thread(pos);
3200                 if (pos == leader) {
3201                         pos = NULL;
3202                         goto out;
3203                 }
3204         }
3205 found:
3206         get_task_struct(pos);
3207 out:
3208         rcu_read_unlock();
3209         return pos;
3210 }
3211
3212 /*
3213  * Find the next thread in the thread list.
3214  * Return NULL if there is an error or no next thread.
3215  *
3216  * The reference to the input task_struct is released.
3217  */
3218 static struct task_struct *next_tid(struct task_struct *start)
3219 {
3220         struct task_struct *pos = NULL;
3221         rcu_read_lock();
3222         if (pid_alive(start)) {
3223                 pos = next_thread(start);
3224                 if (thread_group_leader(pos))
3225                         pos = NULL;
3226                 else
3227                         get_task_struct(pos);
3228         }
3229         rcu_read_unlock();
3230         put_task_struct(start);
3231         return pos;
3232 }
3233
3234 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3235         struct task_struct *task, int tid)
3236 {
3237         char name[PROC_NUMBUF];
3238         int len = snprintf(name, sizeof(name), "%d", tid);
3239         return proc_fill_cache(filp, dirent, filldir, name, len,
3240                                 proc_task_instantiate, task, NULL);
3241 }
3242
3243 /* for the /proc/TGID/task/ directories */
3244 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3245 {
3246         struct dentry *dentry = filp->f_path.dentry;
3247         struct inode *inode = dentry->d_inode;
3248         struct task_struct *leader = NULL;
3249         struct task_struct *task;
3250         int retval = -ENOENT;
3251         ino_t ino;
3252         int tid;
3253         struct pid_namespace *ns;
3254
3255         task = get_proc_task(inode);
3256         if (!task)
3257                 goto out_no_task;
3258         rcu_read_lock();
3259         if (pid_alive(task)) {
3260                 leader = task->group_leader;
3261                 get_task_struct(leader);
3262         }
3263         rcu_read_unlock();
3264         put_task_struct(task);
3265         if (!leader)
3266                 goto out_no_task;
3267         retval = 0;
3268
3269         switch ((unsigned long)filp->f_pos) {
3270         case 0:
3271                 ino = inode->i_ino;
3272                 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) < 0)
3273                         goto out;
3274                 filp->f_pos++;
3275                 /* fall through */
3276         case 1:
3277                 ino = parent_ino(dentry);
3278                 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) < 0)
3279                         goto out;
3280                 filp->f_pos++;
3281                 /* fall through */
3282         }
3283
3284         /* f_version caches the tgid value that the last readdir call couldn't
3285          * return. lseek aka telldir automagically resets f_version to 0.
3286          */
3287         ns = filp->f_dentry->d_sb->s_fs_info;
3288         tid = (int)filp->f_version;
3289         filp->f_version = 0;
3290         for (task = first_tid(leader, tid, filp->f_pos - 2, ns);
3291              task;
3292              task = next_tid(task), filp->f_pos++) {
3293                 tid = task_pid_nr_ns(task, ns);
3294                 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3295                         /* returning this tgid failed, save it as the first
3296                          * pid for the next readir call */
3297                         filp->f_version = (u64)tid;
3298                         put_task_struct(task);
3299                         break;
3300                 }
3301         }
3302 out:
3303         put_task_struct(leader);
3304 out_no_task:
3305         return retval;
3306 }
3307
3308 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3309 {
3310         struct inode *inode = dentry->d_inode;
3311         struct task_struct *p = get_proc_task(inode);
3312         generic_fillattr(inode, stat);
3313
3314         if (p) {
3315                 stat->nlink += get_nr_threads(p);
3316                 put_task_struct(p);
3317         }
3318
3319         return 0;
3320 }
3321
3322 static const struct inode_operations proc_task_inode_operations = {
3323         .lookup         = proc_task_lookup,
3324         .getattr        = proc_task_getattr,
3325         .setattr        = proc_setattr,
3326         .permission     = proc_pid_permission,
3327 };
3328
3329 static const struct file_operations proc_task_operations = {
3330         .read           = generic_read_dir,
3331         .readdir        = proc_task_readdir,
3332         .llseek         = default_llseek,
3333 };