Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
[pandora-kernel.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/cgroup.h>
77 #include <linux/cpuset.h>
78 #include <linux/audit.h>
79 #include <linux/poll.h>
80 #include <linux/nsproxy.h>
81 #include <linux/oom.h>
82 #include <linux/elf.h>
83 #include <linux/pid_namespace.h>
84 #include <linux/fs_struct.h>
85 #include <linux/slab.h>
86 #ifdef CONFIG_HARDWALL
87 #include <asm/hardwall.h>
88 #endif
89 #include "internal.h"
90
91 /* NOTE:
92  *      Implementing inode permission operations in /proc is almost
93  *      certainly an error.  Permission checks need to happen during
94  *      each system call not at open time.  The reason is that most of
95  *      what we wish to check for permissions in /proc varies at runtime.
96  *
97  *      The classic example of a problem is opening file descriptors
98  *      in /proc for a task before it execs a suid executable.
99  */
100
101 struct pid_entry {
102         char *name;
103         int len;
104         mode_t mode;
105         const struct inode_operations *iop;
106         const struct file_operations *fop;
107         union proc_op op;
108 };
109
110 #define NOD(NAME, MODE, IOP, FOP, OP) {                 \
111         .name = (NAME),                                 \
112         .len  = sizeof(NAME) - 1,                       \
113         .mode = MODE,                                   \
114         .iop  = IOP,                                    \
115         .fop  = FOP,                                    \
116         .op   = OP,                                     \
117 }
118
119 #define DIR(NAME, MODE, iops, fops)     \
120         NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
121 #define LNK(NAME, get_link)                                     \
122         NOD(NAME, (S_IFLNK|S_IRWXUGO),                          \
123                 &proc_pid_link_inode_operations, NULL,          \
124                 { .proc_get_link = get_link } )
125 #define REG(NAME, MODE, fops)                           \
126         NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
127 #define INF(NAME, MODE, read)                           \
128         NOD(NAME, (S_IFREG|(MODE)),                     \
129                 NULL, &proc_info_file_operations,       \
130                 { .proc_read = read } )
131 #define ONE(NAME, MODE, show)                           \
132         NOD(NAME, (S_IFREG|(MODE)),                     \
133                 NULL, &proc_single_file_operations,     \
134                 { .proc_show = show } )
135
136 /*
137  * Count the number of hardlinks for the pid_entry table, excluding the .
138  * and .. links.
139  */
140 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
141         unsigned int n)
142 {
143         unsigned int i;
144         unsigned int count;
145
146         count = 0;
147         for (i = 0; i < n; ++i) {
148                 if (S_ISDIR(entries[i].mode))
149                         ++count;
150         }
151
152         return count;
153 }
154
155 static int get_task_root(struct task_struct *task, struct path *root)
156 {
157         int result = -ENOENT;
158
159         task_lock(task);
160         if (task->fs) {
161                 get_fs_root(task->fs, root);
162                 result = 0;
163         }
164         task_unlock(task);
165         return result;
166 }
167
168 static int proc_cwd_link(struct inode *inode, struct path *path)
169 {
170         struct task_struct *task = get_proc_task(inode);
171         int result = -ENOENT;
172
173         if (task) {
174                 task_lock(task);
175                 if (task->fs) {
176                         get_fs_pwd(task->fs, path);
177                         result = 0;
178                 }
179                 task_unlock(task);
180                 put_task_struct(task);
181         }
182         return result;
183 }
184
185 static int proc_root_link(struct inode *inode, struct path *path)
186 {
187         struct task_struct *task = get_proc_task(inode);
188         int result = -ENOENT;
189
190         if (task) {
191                 result = get_task_root(task, path);
192                 put_task_struct(task);
193         }
194         return result;
195 }
196
197 static struct mm_struct *__check_mem_permission(struct task_struct *task)
198 {
199         struct mm_struct *mm;
200
201         mm = get_task_mm(task);
202         if (!mm)
203                 return ERR_PTR(-EINVAL);
204
205         /*
206          * A task can always look at itself, in case it chooses
207          * to use system calls instead of load instructions.
208          */
209         if (task == current)
210                 return mm;
211
212         /*
213          * If current is actively ptrace'ing, and would also be
214          * permitted to freshly attach with ptrace now, permit it.
215          */
216         if (task_is_stopped_or_traced(task)) {
217                 int match;
218                 rcu_read_lock();
219                 match = (tracehook_tracer_task(task) == current);
220                 rcu_read_unlock();
221                 if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
222                         return mm;
223         }
224
225         /*
226          * No one else is allowed.
227          */
228         mmput(mm);
229         return ERR_PTR(-EPERM);
230 }
231
232 /*
233  * If current may access user memory in @task return a reference to the
234  * corresponding mm, otherwise ERR_PTR.
235  */
236 static struct mm_struct *check_mem_permission(struct task_struct *task)
237 {
238         struct mm_struct *mm;
239         int err;
240
241         /*
242          * Avoid racing if task exec's as we might get a new mm but validate
243          * against old credentials.
244          */
245         err = mutex_lock_killable(&task->signal->cred_guard_mutex);
246         if (err)
247                 return ERR_PTR(err);
248
249         mm = __check_mem_permission(task);
250         mutex_unlock(&task->signal->cred_guard_mutex);
251
252         return mm;
253 }
254
255 struct mm_struct *mm_for_maps(struct task_struct *task)
256 {
257         struct mm_struct *mm;
258         int err;
259
260         err =  mutex_lock_killable(&task->signal->cred_guard_mutex);
261         if (err)
262                 return ERR_PTR(err);
263
264         mm = get_task_mm(task);
265         if (mm && mm != current->mm &&
266                         !ptrace_may_access(task, PTRACE_MODE_READ)) {
267                 mmput(mm);
268                 mm = ERR_PTR(-EACCES);
269         }
270         mutex_unlock(&task->signal->cred_guard_mutex);
271
272         return mm;
273 }
274
275 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
276 {
277         int res = 0;
278         unsigned int len;
279         struct mm_struct *mm = get_task_mm(task);
280         if (!mm)
281                 goto out;
282         if (!mm->arg_end)
283                 goto out_mm;    /* Shh! No looking before we're done */
284
285         len = mm->arg_end - mm->arg_start;
286  
287         if (len > PAGE_SIZE)
288                 len = PAGE_SIZE;
289  
290         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
291
292         // If the nul at the end of args has been overwritten, then
293         // assume application is using setproctitle(3).
294         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
295                 len = strnlen(buffer, res);
296                 if (len < res) {
297                     res = len;
298                 } else {
299                         len = mm->env_end - mm->env_start;
300                         if (len > PAGE_SIZE - res)
301                                 len = PAGE_SIZE - res;
302                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
303                         res = strnlen(buffer, res);
304                 }
305         }
306 out_mm:
307         mmput(mm);
308 out:
309         return res;
310 }
311
312 static int proc_pid_auxv(struct task_struct *task, char *buffer)
313 {
314         struct mm_struct *mm = mm_for_maps(task);
315         int res = PTR_ERR(mm);
316         if (mm && !IS_ERR(mm)) {
317                 unsigned int nwords = 0;
318                 do {
319                         nwords += 2;
320                 } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
321                 res = nwords * sizeof(mm->saved_auxv[0]);
322                 if (res > PAGE_SIZE)
323                         res = PAGE_SIZE;
324                 memcpy(buffer, mm->saved_auxv, res);
325                 mmput(mm);
326         }
327         return res;
328 }
329
330
331 #ifdef CONFIG_KALLSYMS
332 /*
333  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
334  * Returns the resolved symbol.  If that fails, simply return the address.
335  */
336 static int proc_pid_wchan(struct task_struct *task, char *buffer)
337 {
338         unsigned long wchan;
339         char symname[KSYM_NAME_LEN];
340
341         wchan = get_wchan(task);
342
343         if (lookup_symbol_name(wchan, symname) < 0)
344                 if (!ptrace_may_access(task, PTRACE_MODE_READ))
345                         return 0;
346                 else
347                         return sprintf(buffer, "%lu", wchan);
348         else
349                 return sprintf(buffer, "%s", symname);
350 }
351 #endif /* CONFIG_KALLSYMS */
352
353 static int lock_trace(struct task_struct *task)
354 {
355         int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
356         if (err)
357                 return err;
358         if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
359                 mutex_unlock(&task->signal->cred_guard_mutex);
360                 return -EPERM;
361         }
362         return 0;
363 }
364
365 static void unlock_trace(struct task_struct *task)
366 {
367         mutex_unlock(&task->signal->cred_guard_mutex);
368 }
369
370 #ifdef CONFIG_STACKTRACE
371
372 #define MAX_STACK_TRACE_DEPTH   64
373
374 static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
375                           struct pid *pid, struct task_struct *task)
376 {
377         struct stack_trace trace;
378         unsigned long *entries;
379         int err;
380         int i;
381
382         entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
383         if (!entries)
384                 return -ENOMEM;
385
386         trace.nr_entries        = 0;
387         trace.max_entries       = MAX_STACK_TRACE_DEPTH;
388         trace.entries           = entries;
389         trace.skip              = 0;
390
391         err = lock_trace(task);
392         if (!err) {
393                 save_stack_trace_tsk(task, &trace);
394
395                 for (i = 0; i < trace.nr_entries; i++) {
396                         seq_printf(m, "[<%pK>] %pS\n",
397                                    (void *)entries[i], (void *)entries[i]);
398                 }
399                 unlock_trace(task);
400         }
401         kfree(entries);
402
403         return err;
404 }
405 #endif
406
407 #ifdef CONFIG_SCHEDSTATS
408 /*
409  * Provides /proc/PID/schedstat
410  */
411 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
412 {
413         return sprintf(buffer, "%llu %llu %lu\n",
414                         (unsigned long long)task->se.sum_exec_runtime,
415                         (unsigned long long)task->sched_info.run_delay,
416                         task->sched_info.pcount);
417 }
418 #endif
419
420 #ifdef CONFIG_LATENCYTOP
421 static int lstats_show_proc(struct seq_file *m, void *v)
422 {
423         int i;
424         struct inode *inode = m->private;
425         struct task_struct *task = get_proc_task(inode);
426
427         if (!task)
428                 return -ESRCH;
429         seq_puts(m, "Latency Top version : v0.1\n");
430         for (i = 0; i < 32; i++) {
431                 struct latency_record *lr = &task->latency_record[i];
432                 if (lr->backtrace[0]) {
433                         int q;
434                         seq_printf(m, "%i %li %li",
435                                    lr->count, lr->time, lr->max);
436                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
437                                 unsigned long bt = lr->backtrace[q];
438                                 if (!bt)
439                                         break;
440                                 if (bt == ULONG_MAX)
441                                         break;
442                                 seq_printf(m, " %ps", (void *)bt);
443                         }
444                         seq_putc(m, '\n');
445                 }
446
447         }
448         put_task_struct(task);
449         return 0;
450 }
451
452 static int lstats_open(struct inode *inode, struct file *file)
453 {
454         return single_open(file, lstats_show_proc, inode);
455 }
456
457 static ssize_t lstats_write(struct file *file, const char __user *buf,
458                             size_t count, loff_t *offs)
459 {
460         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
461
462         if (!task)
463                 return -ESRCH;
464         clear_all_latency_tracing(task);
465         put_task_struct(task);
466
467         return count;
468 }
469
470 static const struct file_operations proc_lstats_operations = {
471         .open           = lstats_open,
472         .read           = seq_read,
473         .write          = lstats_write,
474         .llseek         = seq_lseek,
475         .release        = single_release,
476 };
477
478 #endif
479
480 static int proc_oom_score(struct task_struct *task, char *buffer)
481 {
482         unsigned long points = 0;
483
484         read_lock(&tasklist_lock);
485         if (pid_alive(task))
486                 points = oom_badness(task, NULL, NULL,
487                                         totalram_pages + total_swap_pages);
488         read_unlock(&tasklist_lock);
489         return sprintf(buffer, "%lu\n", points);
490 }
491
492 struct limit_names {
493         char *name;
494         char *unit;
495 };
496
497 static const struct limit_names lnames[RLIM_NLIMITS] = {
498         [RLIMIT_CPU] = {"Max cpu time", "seconds"},
499         [RLIMIT_FSIZE] = {"Max file size", "bytes"},
500         [RLIMIT_DATA] = {"Max data size", "bytes"},
501         [RLIMIT_STACK] = {"Max stack size", "bytes"},
502         [RLIMIT_CORE] = {"Max core file size", "bytes"},
503         [RLIMIT_RSS] = {"Max resident set", "bytes"},
504         [RLIMIT_NPROC] = {"Max processes", "processes"},
505         [RLIMIT_NOFILE] = {"Max open files", "files"},
506         [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
507         [RLIMIT_AS] = {"Max address space", "bytes"},
508         [RLIMIT_LOCKS] = {"Max file locks", "locks"},
509         [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
510         [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
511         [RLIMIT_NICE] = {"Max nice priority", NULL},
512         [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
513         [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
514 };
515
516 /* Display limits for a process */
517 static int proc_pid_limits(struct task_struct *task, char *buffer)
518 {
519         unsigned int i;
520         int count = 0;
521         unsigned long flags;
522         char *bufptr = buffer;
523
524         struct rlimit rlim[RLIM_NLIMITS];
525
526         if (!lock_task_sighand(task, &flags))
527                 return 0;
528         memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
529         unlock_task_sighand(task, &flags);
530
531         /*
532          * print the file header
533          */
534         count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
535                         "Limit", "Soft Limit", "Hard Limit", "Units");
536
537         for (i = 0; i < RLIM_NLIMITS; i++) {
538                 if (rlim[i].rlim_cur == RLIM_INFINITY)
539                         count += sprintf(&bufptr[count], "%-25s %-20s ",
540                                          lnames[i].name, "unlimited");
541                 else
542                         count += sprintf(&bufptr[count], "%-25s %-20lu ",
543                                          lnames[i].name, rlim[i].rlim_cur);
544
545                 if (rlim[i].rlim_max == RLIM_INFINITY)
546                         count += sprintf(&bufptr[count], "%-20s ", "unlimited");
547                 else
548                         count += sprintf(&bufptr[count], "%-20lu ",
549                                          rlim[i].rlim_max);
550
551                 if (lnames[i].unit)
552                         count += sprintf(&bufptr[count], "%-10s\n",
553                                          lnames[i].unit);
554                 else
555                         count += sprintf(&bufptr[count], "\n");
556         }
557
558         return count;
559 }
560
561 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
562 static int proc_pid_syscall(struct task_struct *task, char *buffer)
563 {
564         long nr;
565         unsigned long args[6], sp, pc;
566         int res = lock_trace(task);
567         if (res)
568                 return res;
569
570         if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
571                 res = sprintf(buffer, "running\n");
572         else if (nr < 0)
573                 res = sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
574         else
575                 res = sprintf(buffer,
576                        "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
577                        nr,
578                        args[0], args[1], args[2], args[3], args[4], args[5],
579                        sp, pc);
580         unlock_trace(task);
581         return res;
582 }
583 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
584
585 /************************************************************************/
586 /*                       Here the fs part begins                        */
587 /************************************************************************/
588
589 /* permission checks */
590 static int proc_fd_access_allowed(struct inode *inode)
591 {
592         struct task_struct *task;
593         int allowed = 0;
594         /* Allow access to a task's file descriptors if it is us or we
595          * may use ptrace attach to the process and find out that
596          * information.
597          */
598         task = get_proc_task(inode);
599         if (task) {
600                 allowed = ptrace_may_access(task, PTRACE_MODE_READ);
601                 put_task_struct(task);
602         }
603         return allowed;
604 }
605
606 int proc_setattr(struct dentry *dentry, struct iattr *attr)
607 {
608         int error;
609         struct inode *inode = dentry->d_inode;
610
611         if (attr->ia_valid & ATTR_MODE)
612                 return -EPERM;
613
614         error = inode_change_ok(inode, attr);
615         if (error)
616                 return error;
617
618         if ((attr->ia_valid & ATTR_SIZE) &&
619             attr->ia_size != i_size_read(inode)) {
620                 error = vmtruncate(inode, attr->ia_size);
621                 if (error)
622                         return error;
623         }
624
625         setattr_copy(inode, attr);
626         mark_inode_dirty(inode);
627         return 0;
628 }
629
630 static const struct inode_operations proc_def_inode_operations = {
631         .setattr        = proc_setattr,
632 };
633
634 static int mounts_open_common(struct inode *inode, struct file *file,
635                               const struct seq_operations *op)
636 {
637         struct task_struct *task = get_proc_task(inode);
638         struct nsproxy *nsp;
639         struct mnt_namespace *ns = NULL;
640         struct path root;
641         struct proc_mounts *p;
642         int ret = -EINVAL;
643
644         if (task) {
645                 rcu_read_lock();
646                 nsp = task_nsproxy(task);
647                 if (nsp) {
648                         ns = nsp->mnt_ns;
649                         if (ns)
650                                 get_mnt_ns(ns);
651                 }
652                 rcu_read_unlock();
653                 if (ns && get_task_root(task, &root) == 0)
654                         ret = 0;
655                 put_task_struct(task);
656         }
657
658         if (!ns)
659                 goto err;
660         if (ret)
661                 goto err_put_ns;
662
663         ret = -ENOMEM;
664         p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
665         if (!p)
666                 goto err_put_path;
667
668         file->private_data = &p->m;
669         ret = seq_open(file, op);
670         if (ret)
671                 goto err_free;
672
673         p->m.private = p;
674         p->ns = ns;
675         p->root = root;
676         p->event = ns->event;
677
678         return 0;
679
680  err_free:
681         kfree(p);
682  err_put_path:
683         path_put(&root);
684  err_put_ns:
685         put_mnt_ns(ns);
686  err:
687         return ret;
688 }
689
690 static int mounts_release(struct inode *inode, struct file *file)
691 {
692         struct proc_mounts *p = file->private_data;
693         path_put(&p->root);
694         put_mnt_ns(p->ns);
695         return seq_release(inode, file);
696 }
697
698 static unsigned mounts_poll(struct file *file, poll_table *wait)
699 {
700         struct proc_mounts *p = file->private_data;
701         unsigned res = POLLIN | POLLRDNORM;
702
703         poll_wait(file, &p->ns->poll, wait);
704         if (mnt_had_events(p))
705                 res |= POLLERR | POLLPRI;
706
707         return res;
708 }
709
710 static int mounts_open(struct inode *inode, struct file *file)
711 {
712         return mounts_open_common(inode, file, &mounts_op);
713 }
714
715 static const struct file_operations proc_mounts_operations = {
716         .open           = mounts_open,
717         .read           = seq_read,
718         .llseek         = seq_lseek,
719         .release        = mounts_release,
720         .poll           = mounts_poll,
721 };
722
723 static int mountinfo_open(struct inode *inode, struct file *file)
724 {
725         return mounts_open_common(inode, file, &mountinfo_op);
726 }
727
728 static const struct file_operations proc_mountinfo_operations = {
729         .open           = mountinfo_open,
730         .read           = seq_read,
731         .llseek         = seq_lseek,
732         .release        = mounts_release,
733         .poll           = mounts_poll,
734 };
735
736 static int mountstats_open(struct inode *inode, struct file *file)
737 {
738         return mounts_open_common(inode, file, &mountstats_op);
739 }
740
741 static const struct file_operations proc_mountstats_operations = {
742         .open           = mountstats_open,
743         .read           = seq_read,
744         .llseek         = seq_lseek,
745         .release        = mounts_release,
746 };
747
748 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
749
750 static ssize_t proc_info_read(struct file * file, char __user * buf,
751                           size_t count, loff_t *ppos)
752 {
753         struct inode * inode = file->f_path.dentry->d_inode;
754         unsigned long page;
755         ssize_t length;
756         struct task_struct *task = get_proc_task(inode);
757
758         length = -ESRCH;
759         if (!task)
760                 goto out_no_task;
761
762         if (count > PROC_BLOCK_SIZE)
763                 count = PROC_BLOCK_SIZE;
764
765         length = -ENOMEM;
766         if (!(page = __get_free_page(GFP_TEMPORARY)))
767                 goto out;
768
769         length = PROC_I(inode)->op.proc_read(task, (char*)page);
770
771         if (length >= 0)
772                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
773         free_page(page);
774 out:
775         put_task_struct(task);
776 out_no_task:
777         return length;
778 }
779
780 static const struct file_operations proc_info_file_operations = {
781         .read           = proc_info_read,
782         .llseek         = generic_file_llseek,
783 };
784
785 static int proc_single_show(struct seq_file *m, void *v)
786 {
787         struct inode *inode = m->private;
788         struct pid_namespace *ns;
789         struct pid *pid;
790         struct task_struct *task;
791         int ret;
792
793         ns = inode->i_sb->s_fs_info;
794         pid = proc_pid(inode);
795         task = get_pid_task(pid, PIDTYPE_PID);
796         if (!task)
797                 return -ESRCH;
798
799         ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
800
801         put_task_struct(task);
802         return ret;
803 }
804
805 static int proc_single_open(struct inode *inode, struct file *filp)
806 {
807         return single_open(filp, proc_single_show, inode);
808 }
809
810 static const struct file_operations proc_single_file_operations = {
811         .open           = proc_single_open,
812         .read           = seq_read,
813         .llseek         = seq_lseek,
814         .release        = single_release,
815 };
816
817 static int mem_open(struct inode* inode, struct file* file)
818 {
819         file->private_data = (void*)((long)current->self_exec_id);
820         /* OK to pass negative loff_t, we can catch out-of-range */
821         file->f_mode |= FMODE_UNSIGNED_OFFSET;
822         return 0;
823 }
824
825 static ssize_t mem_read(struct file * file, char __user * buf,
826                         size_t count, loff_t *ppos)
827 {
828         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
829         char *page;
830         unsigned long src = *ppos;
831         int ret = -ESRCH;
832         struct mm_struct *mm;
833
834         if (!task)
835                 goto out_no_task;
836
837         ret = -ENOMEM;
838         page = (char *)__get_free_page(GFP_TEMPORARY);
839         if (!page)
840                 goto out;
841
842         mm = check_mem_permission(task);
843         ret = PTR_ERR(mm);
844         if (IS_ERR(mm))
845                 goto out_free;
846
847         ret = -EIO;
848  
849         if (file->private_data != (void*)((long)current->self_exec_id))
850                 goto out_put;
851
852         ret = 0;
853  
854         while (count > 0) {
855                 int this_len, retval;
856
857                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
858                 retval = access_remote_vm(mm, src, page, this_len, 0);
859                 if (!retval) {
860                         if (!ret)
861                                 ret = -EIO;
862                         break;
863                 }
864
865                 if (copy_to_user(buf, page, retval)) {
866                         ret = -EFAULT;
867                         break;
868                 }
869  
870                 ret += retval;
871                 src += retval;
872                 buf += retval;
873                 count -= retval;
874         }
875         *ppos = src;
876
877 out_put:
878         mmput(mm);
879 out_free:
880         free_page((unsigned long) page);
881 out:
882         put_task_struct(task);
883 out_no_task:
884         return ret;
885 }
886
887 static ssize_t mem_write(struct file * file, const char __user *buf,
888                          size_t count, loff_t *ppos)
889 {
890         int copied;
891         char *page;
892         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
893         unsigned long dst = *ppos;
894         struct mm_struct *mm;
895
896         copied = -ESRCH;
897         if (!task)
898                 goto out_no_task;
899
900         copied = -ENOMEM;
901         page = (char *)__get_free_page(GFP_TEMPORARY);
902         if (!page)
903                 goto out_task;
904
905         mm = check_mem_permission(task);
906         copied = PTR_ERR(mm);
907         if (IS_ERR(mm))
908                 goto out_free;
909
910         copied = -EIO;
911         if (file->private_data != (void *)((long)current->self_exec_id))
912                 goto out_mm;
913
914         copied = 0;
915         while (count > 0) {
916                 int this_len, retval;
917
918                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
919                 if (copy_from_user(page, buf, this_len)) {
920                         copied = -EFAULT;
921                         break;
922                 }
923                 retval = access_remote_vm(mm, dst, page, this_len, 1);
924                 if (!retval) {
925                         if (!copied)
926                                 copied = -EIO;
927                         break;
928                 }
929                 copied += retval;
930                 buf += retval;
931                 dst += retval;
932                 count -= retval;                        
933         }
934         *ppos = dst;
935
936 out_mm:
937         mmput(mm);
938 out_free:
939         free_page((unsigned long) page);
940 out_task:
941         put_task_struct(task);
942 out_no_task:
943         return copied;
944 }
945
946 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
947 {
948         switch (orig) {
949         case 0:
950                 file->f_pos = offset;
951                 break;
952         case 1:
953                 file->f_pos += offset;
954                 break;
955         default:
956                 return -EINVAL;
957         }
958         force_successful_syscall_return();
959         return file->f_pos;
960 }
961
962 static const struct file_operations proc_mem_operations = {
963         .llseek         = mem_lseek,
964         .read           = mem_read,
965         .write          = mem_write,
966         .open           = mem_open,
967 };
968
969 static ssize_t environ_read(struct file *file, char __user *buf,
970                         size_t count, loff_t *ppos)
971 {
972         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
973         char *page;
974         unsigned long src = *ppos;
975         int ret = -ESRCH;
976         struct mm_struct *mm;
977
978         if (!task)
979                 goto out_no_task;
980
981         ret = -ENOMEM;
982         page = (char *)__get_free_page(GFP_TEMPORARY);
983         if (!page)
984                 goto out;
985
986
987         mm = mm_for_maps(task);
988         ret = PTR_ERR(mm);
989         if (!mm || IS_ERR(mm))
990                 goto out_free;
991
992         ret = 0;
993         while (count > 0) {
994                 int this_len, retval, max_len;
995
996                 this_len = mm->env_end - (mm->env_start + src);
997
998                 if (this_len <= 0)
999                         break;
1000
1001                 max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
1002                 this_len = (this_len > max_len) ? max_len : this_len;
1003
1004                 retval = access_process_vm(task, (mm->env_start + src),
1005                         page, this_len, 0);
1006
1007                 if (retval <= 0) {
1008                         ret = retval;
1009                         break;
1010                 }
1011
1012                 if (copy_to_user(buf, page, retval)) {
1013                         ret = -EFAULT;
1014                         break;
1015                 }
1016
1017                 ret += retval;
1018                 src += retval;
1019                 buf += retval;
1020                 count -= retval;
1021         }
1022         *ppos = src;
1023
1024         mmput(mm);
1025 out_free:
1026         free_page((unsigned long) page);
1027 out:
1028         put_task_struct(task);
1029 out_no_task:
1030         return ret;
1031 }
1032
1033 static const struct file_operations proc_environ_operations = {
1034         .read           = environ_read,
1035         .llseek         = generic_file_llseek,
1036 };
1037
1038 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
1039                                 size_t count, loff_t *ppos)
1040 {
1041         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1042         char buffer[PROC_NUMBUF];
1043         size_t len;
1044         int oom_adjust = OOM_DISABLE;
1045         unsigned long flags;
1046
1047         if (!task)
1048                 return -ESRCH;
1049
1050         if (lock_task_sighand(task, &flags)) {
1051                 oom_adjust = task->signal->oom_adj;
1052                 unlock_task_sighand(task, &flags);
1053         }
1054
1055         put_task_struct(task);
1056
1057         len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
1058
1059         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1060 }
1061
1062 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
1063                                 size_t count, loff_t *ppos)
1064 {
1065         struct task_struct *task;
1066         char buffer[PROC_NUMBUF];
1067         int oom_adjust;
1068         unsigned long flags;
1069         int err;
1070
1071         memset(buffer, 0, sizeof(buffer));
1072         if (count > sizeof(buffer) - 1)
1073                 count = sizeof(buffer) - 1;
1074         if (copy_from_user(buffer, buf, count)) {
1075                 err = -EFAULT;
1076                 goto out;
1077         }
1078
1079         err = kstrtoint(strstrip(buffer), 0, &oom_adjust);
1080         if (err)
1081                 goto out;
1082         if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
1083              oom_adjust != OOM_DISABLE) {
1084                 err = -EINVAL;
1085                 goto out;
1086         }
1087
1088         task = get_proc_task(file->f_path.dentry->d_inode);
1089         if (!task) {
1090                 err = -ESRCH;
1091                 goto out;
1092         }
1093
1094         task_lock(task);
1095         if (!task->mm) {
1096                 err = -EINVAL;
1097                 goto err_task_lock;
1098         }
1099
1100         if (!lock_task_sighand(task, &flags)) {
1101                 err = -ESRCH;
1102                 goto err_task_lock;
1103         }
1104
1105         if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
1106                 err = -EACCES;
1107                 goto err_sighand;
1108         }
1109
1110         if (oom_adjust != task->signal->oom_adj) {
1111                 if (oom_adjust == OOM_DISABLE)
1112                         atomic_inc(&task->mm->oom_disable_count);
1113                 if (task->signal->oom_adj == OOM_DISABLE)
1114                         atomic_dec(&task->mm->oom_disable_count);
1115         }
1116
1117         /*
1118          * Warn that /proc/pid/oom_adj is deprecated, see
1119          * Documentation/feature-removal-schedule.txt.
1120          */
1121         printk_once(KERN_WARNING "%s (%d): /proc/%d/oom_adj is deprecated, "
1122                         "please use /proc/%d/oom_score_adj instead.\n",
1123                         current->comm, task_pid_nr(current),
1124                         task_pid_nr(task), task_pid_nr(task));
1125         task->signal->oom_adj = oom_adjust;
1126         /*
1127          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1128          * value is always attainable.
1129          */
1130         if (task->signal->oom_adj == OOM_ADJUST_MAX)
1131                 task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX;
1132         else
1133                 task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
1134                                                                 -OOM_DISABLE;
1135 err_sighand:
1136         unlock_task_sighand(task, &flags);
1137 err_task_lock:
1138         task_unlock(task);
1139         put_task_struct(task);
1140 out:
1141         return err < 0 ? err : count;
1142 }
1143
1144 static const struct file_operations proc_oom_adjust_operations = {
1145         .read           = oom_adjust_read,
1146         .write          = oom_adjust_write,
1147         .llseek         = generic_file_llseek,
1148 };
1149
1150 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1151                                         size_t count, loff_t *ppos)
1152 {
1153         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1154         char buffer[PROC_NUMBUF];
1155         int oom_score_adj = OOM_SCORE_ADJ_MIN;
1156         unsigned long flags;
1157         size_t len;
1158
1159         if (!task)
1160                 return -ESRCH;
1161         if (lock_task_sighand(task, &flags)) {
1162                 oom_score_adj = task->signal->oom_score_adj;
1163                 unlock_task_sighand(task, &flags);
1164         }
1165         put_task_struct(task);
1166         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj);
1167         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1168 }
1169
1170 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1171                                         size_t count, loff_t *ppos)
1172 {
1173         struct task_struct *task;
1174         char buffer[PROC_NUMBUF];
1175         unsigned long flags;
1176         int oom_score_adj;
1177         int err;
1178
1179         memset(buffer, 0, sizeof(buffer));
1180         if (count > sizeof(buffer) - 1)
1181                 count = sizeof(buffer) - 1;
1182         if (copy_from_user(buffer, buf, count)) {
1183                 err = -EFAULT;
1184                 goto out;
1185         }
1186
1187         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1188         if (err)
1189                 goto out;
1190         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1191                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1192                 err = -EINVAL;
1193                 goto out;
1194         }
1195
1196         task = get_proc_task(file->f_path.dentry->d_inode);
1197         if (!task) {
1198                 err = -ESRCH;
1199                 goto out;
1200         }
1201
1202         task_lock(task);
1203         if (!task->mm) {
1204                 err = -EINVAL;
1205                 goto err_task_lock;
1206         }
1207
1208         if (!lock_task_sighand(task, &flags)) {
1209                 err = -ESRCH;
1210                 goto err_task_lock;
1211         }
1212
1213         if (oom_score_adj < task->signal->oom_score_adj_min &&
1214                         !capable(CAP_SYS_RESOURCE)) {
1215                 err = -EACCES;
1216                 goto err_sighand;
1217         }
1218
1219         if (oom_score_adj != task->signal->oom_score_adj) {
1220                 if (oom_score_adj == OOM_SCORE_ADJ_MIN)
1221                         atomic_inc(&task->mm->oom_disable_count);
1222                 if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1223                         atomic_dec(&task->mm->oom_disable_count);
1224         }
1225         task->signal->oom_score_adj = oom_score_adj;
1226         if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1227                 task->signal->oom_score_adj_min = oom_score_adj;
1228         /*
1229          * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
1230          * always attainable.
1231          */
1232         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1233                 task->signal->oom_adj = OOM_DISABLE;
1234         else
1235                 task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
1236                                                         OOM_SCORE_ADJ_MAX;
1237 err_sighand:
1238         unlock_task_sighand(task, &flags);
1239 err_task_lock:
1240         task_unlock(task);
1241         put_task_struct(task);
1242 out:
1243         return err < 0 ? err : count;
1244 }
1245
1246 static const struct file_operations proc_oom_score_adj_operations = {
1247         .read           = oom_score_adj_read,
1248         .write          = oom_score_adj_write,
1249         .llseek         = default_llseek,
1250 };
1251
1252 #ifdef CONFIG_AUDITSYSCALL
1253 #define TMPBUFLEN 21
1254 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1255                                   size_t count, loff_t *ppos)
1256 {
1257         struct inode * inode = file->f_path.dentry->d_inode;
1258         struct task_struct *task = get_proc_task(inode);
1259         ssize_t length;
1260         char tmpbuf[TMPBUFLEN];
1261
1262         if (!task)
1263                 return -ESRCH;
1264         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1265                                 audit_get_loginuid(task));
1266         put_task_struct(task);
1267         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1268 }
1269
1270 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1271                                    size_t count, loff_t *ppos)
1272 {
1273         struct inode * inode = file->f_path.dentry->d_inode;
1274         char *page, *tmp;
1275         ssize_t length;
1276         uid_t loginuid;
1277
1278         if (!capable(CAP_AUDIT_CONTROL))
1279                 return -EPERM;
1280
1281         rcu_read_lock();
1282         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1283                 rcu_read_unlock();
1284                 return -EPERM;
1285         }
1286         rcu_read_unlock();
1287
1288         if (count >= PAGE_SIZE)
1289                 count = PAGE_SIZE - 1;
1290
1291         if (*ppos != 0) {
1292                 /* No partial writes. */
1293                 return -EINVAL;
1294         }
1295         page = (char*)__get_free_page(GFP_TEMPORARY);
1296         if (!page)
1297                 return -ENOMEM;
1298         length = -EFAULT;
1299         if (copy_from_user(page, buf, count))
1300                 goto out_free_page;
1301
1302         page[count] = '\0';
1303         loginuid = simple_strtoul(page, &tmp, 10);
1304         if (tmp == page) {
1305                 length = -EINVAL;
1306                 goto out_free_page;
1307
1308         }
1309         length = audit_set_loginuid(current, loginuid);
1310         if (likely(length == 0))
1311                 length = count;
1312
1313 out_free_page:
1314         free_page((unsigned long) page);
1315         return length;
1316 }
1317
1318 static const struct file_operations proc_loginuid_operations = {
1319         .read           = proc_loginuid_read,
1320         .write          = proc_loginuid_write,
1321         .llseek         = generic_file_llseek,
1322 };
1323
1324 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1325                                   size_t count, loff_t *ppos)
1326 {
1327         struct inode * inode = file->f_path.dentry->d_inode;
1328         struct task_struct *task = get_proc_task(inode);
1329         ssize_t length;
1330         char tmpbuf[TMPBUFLEN];
1331
1332         if (!task)
1333                 return -ESRCH;
1334         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1335                                 audit_get_sessionid(task));
1336         put_task_struct(task);
1337         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1338 }
1339
1340 static const struct file_operations proc_sessionid_operations = {
1341         .read           = proc_sessionid_read,
1342         .llseek         = generic_file_llseek,
1343 };
1344 #endif
1345
1346 #ifdef CONFIG_FAULT_INJECTION
1347 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1348                                       size_t count, loff_t *ppos)
1349 {
1350         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1351         char buffer[PROC_NUMBUF];
1352         size_t len;
1353         int make_it_fail;
1354
1355         if (!task)
1356                 return -ESRCH;
1357         make_it_fail = task->make_it_fail;
1358         put_task_struct(task);
1359
1360         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1361
1362         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1363 }
1364
1365 static ssize_t proc_fault_inject_write(struct file * file,
1366                         const char __user * buf, size_t count, loff_t *ppos)
1367 {
1368         struct task_struct *task;
1369         char buffer[PROC_NUMBUF], *end;
1370         int make_it_fail;
1371
1372         if (!capable(CAP_SYS_RESOURCE))
1373                 return -EPERM;
1374         memset(buffer, 0, sizeof(buffer));
1375         if (count > sizeof(buffer) - 1)
1376                 count = sizeof(buffer) - 1;
1377         if (copy_from_user(buffer, buf, count))
1378                 return -EFAULT;
1379         make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
1380         if (*end)
1381                 return -EINVAL;
1382         task = get_proc_task(file->f_dentry->d_inode);
1383         if (!task)
1384                 return -ESRCH;
1385         task->make_it_fail = make_it_fail;
1386         put_task_struct(task);
1387
1388         return count;
1389 }
1390
1391 static const struct file_operations proc_fault_inject_operations = {
1392         .read           = proc_fault_inject_read,
1393         .write          = proc_fault_inject_write,
1394         .llseek         = generic_file_llseek,
1395 };
1396 #endif
1397
1398
1399 #ifdef CONFIG_SCHED_DEBUG
1400 /*
1401  * Print out various scheduling related per-task fields:
1402  */
1403 static int sched_show(struct seq_file *m, void *v)
1404 {
1405         struct inode *inode = m->private;
1406         struct task_struct *p;
1407
1408         p = get_proc_task(inode);
1409         if (!p)
1410                 return -ESRCH;
1411         proc_sched_show_task(p, m);
1412
1413         put_task_struct(p);
1414
1415         return 0;
1416 }
1417
1418 static ssize_t
1419 sched_write(struct file *file, const char __user *buf,
1420             size_t count, loff_t *offset)
1421 {
1422         struct inode *inode = file->f_path.dentry->d_inode;
1423         struct task_struct *p;
1424
1425         p = get_proc_task(inode);
1426         if (!p)
1427                 return -ESRCH;
1428         proc_sched_set_task(p);
1429
1430         put_task_struct(p);
1431
1432         return count;
1433 }
1434
1435 static int sched_open(struct inode *inode, struct file *filp)
1436 {
1437         return single_open(filp, sched_show, inode);
1438 }
1439
1440 static const struct file_operations proc_pid_sched_operations = {
1441         .open           = sched_open,
1442         .read           = seq_read,
1443         .write          = sched_write,
1444         .llseek         = seq_lseek,
1445         .release        = single_release,
1446 };
1447
1448 #endif
1449
1450 #ifdef CONFIG_SCHED_AUTOGROUP
1451 /*
1452  * Print out autogroup related information:
1453  */
1454 static int sched_autogroup_show(struct seq_file *m, void *v)
1455 {
1456         struct inode *inode = m->private;
1457         struct task_struct *p;
1458
1459         p = get_proc_task(inode);
1460         if (!p)
1461                 return -ESRCH;
1462         proc_sched_autogroup_show_task(p, m);
1463
1464         put_task_struct(p);
1465
1466         return 0;
1467 }
1468
1469 static ssize_t
1470 sched_autogroup_write(struct file *file, const char __user *buf,
1471             size_t count, loff_t *offset)
1472 {
1473         struct inode *inode = file->f_path.dentry->d_inode;
1474         struct task_struct *p;
1475         char buffer[PROC_NUMBUF];
1476         int nice;
1477         int err;
1478
1479         memset(buffer, 0, sizeof(buffer));
1480         if (count > sizeof(buffer) - 1)
1481                 count = sizeof(buffer) - 1;
1482         if (copy_from_user(buffer, buf, count))
1483                 return -EFAULT;
1484
1485         err = kstrtoint(strstrip(buffer), 0, &nice);
1486         if (err < 0)
1487                 return err;
1488
1489         p = get_proc_task(inode);
1490         if (!p)
1491                 return -ESRCH;
1492
1493         err = nice;
1494         err = proc_sched_autogroup_set_nice(p, &err);
1495         if (err)
1496                 count = err;
1497
1498         put_task_struct(p);
1499
1500         return count;
1501 }
1502
1503 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1504 {
1505         int ret;
1506
1507         ret = single_open(filp, sched_autogroup_show, NULL);
1508         if (!ret) {
1509                 struct seq_file *m = filp->private_data;
1510
1511                 m->private = inode;
1512         }
1513         return ret;
1514 }
1515
1516 static const struct file_operations proc_pid_sched_autogroup_operations = {
1517         .open           = sched_autogroup_open,
1518         .read           = seq_read,
1519         .write          = sched_autogroup_write,
1520         .llseek         = seq_lseek,
1521         .release        = single_release,
1522 };
1523
1524 #endif /* CONFIG_SCHED_AUTOGROUP */
1525
1526 static ssize_t comm_write(struct file *file, const char __user *buf,
1527                                 size_t count, loff_t *offset)
1528 {
1529         struct inode *inode = file->f_path.dentry->d_inode;
1530         struct task_struct *p;
1531         char buffer[TASK_COMM_LEN];
1532
1533         memset(buffer, 0, sizeof(buffer));
1534         if (count > sizeof(buffer) - 1)
1535                 count = sizeof(buffer) - 1;
1536         if (copy_from_user(buffer, buf, count))
1537                 return -EFAULT;
1538
1539         p = get_proc_task(inode);
1540         if (!p)
1541                 return -ESRCH;
1542
1543         if (same_thread_group(current, p))
1544                 set_task_comm(p, buffer);
1545         else
1546                 count = -EINVAL;
1547
1548         put_task_struct(p);
1549
1550         return count;
1551 }
1552
1553 static int comm_show(struct seq_file *m, void *v)
1554 {
1555         struct inode *inode = m->private;
1556         struct task_struct *p;
1557
1558         p = get_proc_task(inode);
1559         if (!p)
1560                 return -ESRCH;
1561
1562         task_lock(p);
1563         seq_printf(m, "%s\n", p->comm);
1564         task_unlock(p);
1565
1566         put_task_struct(p);
1567
1568         return 0;
1569 }
1570
1571 static int comm_open(struct inode *inode, struct file *filp)
1572 {
1573         return single_open(filp, comm_show, inode);
1574 }
1575
1576 static const struct file_operations proc_pid_set_comm_operations = {
1577         .open           = comm_open,
1578         .read           = seq_read,
1579         .write          = comm_write,
1580         .llseek         = seq_lseek,
1581         .release        = single_release,
1582 };
1583
1584 static int proc_exe_link(struct inode *inode, struct path *exe_path)
1585 {
1586         struct task_struct *task;
1587         struct mm_struct *mm;
1588         struct file *exe_file;
1589
1590         task = get_proc_task(inode);
1591         if (!task)
1592                 return -ENOENT;
1593         mm = get_task_mm(task);
1594         put_task_struct(task);
1595         if (!mm)
1596                 return -ENOENT;
1597         exe_file = get_mm_exe_file(mm);
1598         mmput(mm);
1599         if (exe_file) {
1600                 *exe_path = exe_file->f_path;
1601                 path_get(&exe_file->f_path);
1602                 fput(exe_file);
1603                 return 0;
1604         } else
1605                 return -ENOENT;
1606 }
1607
1608 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1609 {
1610         struct inode *inode = dentry->d_inode;
1611         int error = -EACCES;
1612
1613         /* We don't need a base pointer in the /proc filesystem */
1614         path_put(&nd->path);
1615
1616         /* Are we allowed to snoop on the tasks file descriptors? */
1617         if (!proc_fd_access_allowed(inode))
1618                 goto out;
1619
1620         error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1621 out:
1622         return ERR_PTR(error);
1623 }
1624
1625 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1626 {
1627         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1628         char *pathname;
1629         int len;
1630
1631         if (!tmp)
1632                 return -ENOMEM;
1633
1634         pathname = d_path(path, tmp, PAGE_SIZE);
1635         len = PTR_ERR(pathname);
1636         if (IS_ERR(pathname))
1637                 goto out;
1638         len = tmp + PAGE_SIZE - 1 - pathname;
1639
1640         if (len > buflen)
1641                 len = buflen;
1642         if (copy_to_user(buffer, pathname, len))
1643                 len = -EFAULT;
1644  out:
1645         free_page((unsigned long)tmp);
1646         return len;
1647 }
1648
1649 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1650 {
1651         int error = -EACCES;
1652         struct inode *inode = dentry->d_inode;
1653         struct path path;
1654
1655         /* Are we allowed to snoop on the tasks file descriptors? */
1656         if (!proc_fd_access_allowed(inode))
1657                 goto out;
1658
1659         error = PROC_I(inode)->op.proc_get_link(inode, &path);
1660         if (error)
1661                 goto out;
1662
1663         error = do_proc_readlink(&path, buffer, buflen);
1664         path_put(&path);
1665 out:
1666         return error;
1667 }
1668
1669 static const struct inode_operations proc_pid_link_inode_operations = {
1670         .readlink       = proc_pid_readlink,
1671         .follow_link    = proc_pid_follow_link,
1672         .setattr        = proc_setattr,
1673 };
1674
1675
1676 /* building an inode */
1677
1678 static int task_dumpable(struct task_struct *task)
1679 {
1680         int dumpable = 0;
1681         struct mm_struct *mm;
1682
1683         task_lock(task);
1684         mm = task->mm;
1685         if (mm)
1686                 dumpable = get_dumpable(mm);
1687         task_unlock(task);
1688         if(dumpable == 1)
1689                 return 1;
1690         return 0;
1691 }
1692
1693 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1694 {
1695         struct inode * inode;
1696         struct proc_inode *ei;
1697         const struct cred *cred;
1698
1699         /* We need a new inode */
1700
1701         inode = new_inode(sb);
1702         if (!inode)
1703                 goto out;
1704
1705         /* Common stuff */
1706         ei = PROC_I(inode);
1707         inode->i_ino = get_next_ino();
1708         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1709         inode->i_op = &proc_def_inode_operations;
1710
1711         /*
1712          * grab the reference to task.
1713          */
1714         ei->pid = get_task_pid(task, PIDTYPE_PID);
1715         if (!ei->pid)
1716                 goto out_unlock;
1717
1718         if (task_dumpable(task)) {
1719                 rcu_read_lock();
1720                 cred = __task_cred(task);
1721                 inode->i_uid = cred->euid;
1722                 inode->i_gid = cred->egid;
1723                 rcu_read_unlock();
1724         }
1725         security_task_to_inode(task, inode);
1726
1727 out:
1728         return inode;
1729
1730 out_unlock:
1731         iput(inode);
1732         return NULL;
1733 }
1734
1735 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1736 {
1737         struct inode *inode = dentry->d_inode;
1738         struct task_struct *task;
1739         const struct cred *cred;
1740
1741         generic_fillattr(inode, stat);
1742
1743         rcu_read_lock();
1744         stat->uid = 0;
1745         stat->gid = 0;
1746         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1747         if (task) {
1748                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1749                     task_dumpable(task)) {
1750                         cred = __task_cred(task);
1751                         stat->uid = cred->euid;
1752                         stat->gid = cred->egid;
1753                 }
1754         }
1755         rcu_read_unlock();
1756         return 0;
1757 }
1758
1759 /* dentry stuff */
1760
1761 /*
1762  *      Exceptional case: normally we are not allowed to unhash a busy
1763  * directory. In this case, however, we can do it - no aliasing problems
1764  * due to the way we treat inodes.
1765  *
1766  * Rewrite the inode's ownerships here because the owning task may have
1767  * performed a setuid(), etc.
1768  *
1769  * Before the /proc/pid/status file was created the only way to read
1770  * the effective uid of a /process was to stat /proc/pid.  Reading
1771  * /proc/pid/status is slow enough that procps and other packages
1772  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1773  * made this apply to all per process world readable and executable
1774  * directories.
1775  */
1776 int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1777 {
1778         struct inode *inode;
1779         struct task_struct *task;
1780         const struct cred *cred;
1781
1782         if (nd && nd->flags & LOOKUP_RCU)
1783                 return -ECHILD;
1784
1785         inode = dentry->d_inode;
1786         task = get_proc_task(inode);
1787
1788         if (task) {
1789                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1790                     task_dumpable(task)) {
1791                         rcu_read_lock();
1792                         cred = __task_cred(task);
1793                         inode->i_uid = cred->euid;
1794                         inode->i_gid = cred->egid;
1795                         rcu_read_unlock();
1796                 } else {
1797                         inode->i_uid = 0;
1798                         inode->i_gid = 0;
1799                 }
1800                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1801                 security_task_to_inode(task, inode);
1802                 put_task_struct(task);
1803                 return 1;
1804         }
1805         d_drop(dentry);
1806         return 0;
1807 }
1808
1809 static int pid_delete_dentry(const struct dentry * dentry)
1810 {
1811         /* Is the task we represent dead?
1812          * If so, then don't put the dentry on the lru list,
1813          * kill it immediately.
1814          */
1815         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1816 }
1817
1818 const struct dentry_operations pid_dentry_operations =
1819 {
1820         .d_revalidate   = pid_revalidate,
1821         .d_delete       = pid_delete_dentry,
1822 };
1823
1824 /* Lookups */
1825
1826 /*
1827  * Fill a directory entry.
1828  *
1829  * If possible create the dcache entry and derive our inode number and
1830  * file type from dcache entry.
1831  *
1832  * Since all of the proc inode numbers are dynamically generated, the inode
1833  * numbers do not exist until the inode is cache.  This means creating the
1834  * the dcache entry in readdir is necessary to keep the inode numbers
1835  * reported by readdir in sync with the inode numbers reported
1836  * by stat.
1837  */
1838 int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1839         const char *name, int len,
1840         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1841 {
1842         struct dentry *child, *dir = filp->f_path.dentry;
1843         struct inode *inode;
1844         struct qstr qname;
1845         ino_t ino = 0;
1846         unsigned type = DT_UNKNOWN;
1847
1848         qname.name = name;
1849         qname.len  = len;
1850         qname.hash = full_name_hash(name, len);
1851
1852         child = d_lookup(dir, &qname);
1853         if (!child) {
1854                 struct dentry *new;
1855                 new = d_alloc(dir, &qname);
1856                 if (new) {
1857                         child = instantiate(dir->d_inode, new, task, ptr);
1858                         if (child)
1859                                 dput(new);
1860                         else
1861                                 child = new;
1862                 }
1863         }
1864         if (!child || IS_ERR(child) || !child->d_inode)
1865                 goto end_instantiate;
1866         inode = child->d_inode;
1867         if (inode) {
1868                 ino = inode->i_ino;
1869                 type = inode->i_mode >> 12;
1870         }
1871         dput(child);
1872 end_instantiate:
1873         if (!ino)
1874                 ino = find_inode_number(dir, &qname);
1875         if (!ino)
1876                 ino = 1;
1877         return filldir(dirent, name, len, filp->f_pos, ino, type);
1878 }
1879
1880 static unsigned name_to_int(struct dentry *dentry)
1881 {
1882         const char *name = dentry->d_name.name;
1883         int len = dentry->d_name.len;
1884         unsigned n = 0;
1885
1886         if (len > 1 && *name == '0')
1887                 goto out;
1888         while (len-- > 0) {
1889                 unsigned c = *name++ - '0';
1890                 if (c > 9)
1891                         goto out;
1892                 if (n >= (~0U-9)/10)
1893                         goto out;
1894                 n *= 10;
1895                 n += c;
1896         }
1897         return n;
1898 out:
1899         return ~0U;
1900 }
1901
1902 #define PROC_FDINFO_MAX 64
1903
1904 static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1905 {
1906         struct task_struct *task = get_proc_task(inode);
1907         struct files_struct *files = NULL;
1908         struct file *file;
1909         int fd = proc_fd(inode);
1910
1911         if (task) {
1912                 files = get_files_struct(task);
1913                 put_task_struct(task);
1914         }
1915         if (files) {
1916                 /*
1917                  * We are not taking a ref to the file structure, so we must
1918                  * hold ->file_lock.
1919                  */
1920                 spin_lock(&files->file_lock);
1921                 file = fcheck_files(files, fd);
1922                 if (file) {
1923                         if (path) {
1924                                 *path = file->f_path;
1925                                 path_get(&file->f_path);
1926                         }
1927                         if (info)
1928                                 snprintf(info, PROC_FDINFO_MAX,
1929                                          "pos:\t%lli\n"
1930                                          "flags:\t0%o\n",
1931                                          (long long) file->f_pos,
1932                                          file->f_flags);
1933                         spin_unlock(&files->file_lock);
1934                         put_files_struct(files);
1935                         return 0;
1936                 }
1937                 spin_unlock(&files->file_lock);
1938                 put_files_struct(files);
1939         }
1940         return -ENOENT;
1941 }
1942
1943 static int proc_fd_link(struct inode *inode, struct path *path)
1944 {
1945         return proc_fd_info(inode, path, NULL);
1946 }
1947
1948 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1949 {
1950         struct inode *inode;
1951         struct task_struct *task;
1952         int fd;
1953         struct files_struct *files;
1954         const struct cred *cred;
1955
1956         if (nd && nd->flags & LOOKUP_RCU)
1957                 return -ECHILD;
1958
1959         inode = dentry->d_inode;
1960         task = get_proc_task(inode);
1961         fd = proc_fd(inode);
1962
1963         if (task) {
1964                 files = get_files_struct(task);
1965                 if (files) {
1966                         rcu_read_lock();
1967                         if (fcheck_files(files, fd)) {
1968                                 rcu_read_unlock();
1969                                 put_files_struct(files);
1970                                 if (task_dumpable(task)) {
1971                                         rcu_read_lock();
1972                                         cred = __task_cred(task);
1973                                         inode->i_uid = cred->euid;
1974                                         inode->i_gid = cred->egid;
1975                                         rcu_read_unlock();
1976                                 } else {
1977                                         inode->i_uid = 0;
1978                                         inode->i_gid = 0;
1979                                 }
1980                                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1981                                 security_task_to_inode(task, inode);
1982                                 put_task_struct(task);
1983                                 return 1;
1984                         }
1985                         rcu_read_unlock();
1986                         put_files_struct(files);
1987                 }
1988                 put_task_struct(task);
1989         }
1990         d_drop(dentry);
1991         return 0;
1992 }
1993
1994 static const struct dentry_operations tid_fd_dentry_operations =
1995 {
1996         .d_revalidate   = tid_fd_revalidate,
1997         .d_delete       = pid_delete_dentry,
1998 };
1999
2000 static struct dentry *proc_fd_instantiate(struct inode *dir,
2001         struct dentry *dentry, struct task_struct *task, const void *ptr)
2002 {
2003         unsigned fd = *(const unsigned *)ptr;
2004         struct file *file;
2005         struct files_struct *files;
2006         struct inode *inode;
2007         struct proc_inode *ei;
2008         struct dentry *error = ERR_PTR(-ENOENT);
2009
2010         inode = proc_pid_make_inode(dir->i_sb, task);
2011         if (!inode)
2012                 goto out;
2013         ei = PROC_I(inode);
2014         ei->fd = fd;
2015         files = get_files_struct(task);
2016         if (!files)
2017                 goto out_iput;
2018         inode->i_mode = S_IFLNK;
2019
2020         /*
2021          * We are not taking a ref to the file structure, so we must
2022          * hold ->file_lock.
2023          */
2024         spin_lock(&files->file_lock);
2025         file = fcheck_files(files, fd);
2026         if (!file)
2027                 goto out_unlock;
2028         if (file->f_mode & FMODE_READ)
2029                 inode->i_mode |= S_IRUSR | S_IXUSR;
2030         if (file->f_mode & FMODE_WRITE)
2031                 inode->i_mode |= S_IWUSR | S_IXUSR;
2032         spin_unlock(&files->file_lock);
2033         put_files_struct(files);
2034
2035         inode->i_op = &proc_pid_link_inode_operations;
2036         inode->i_size = 64;
2037         ei->op.proc_get_link = proc_fd_link;
2038         d_set_d_op(dentry, &tid_fd_dentry_operations);
2039         d_add(dentry, inode);
2040         /* Close the race of the process dying before we return the dentry */
2041         if (tid_fd_revalidate(dentry, NULL))
2042                 error = NULL;
2043
2044  out:
2045         return error;
2046 out_unlock:
2047         spin_unlock(&files->file_lock);
2048         put_files_struct(files);
2049 out_iput:
2050         iput(inode);
2051         goto out;
2052 }
2053
2054 static struct dentry *proc_lookupfd_common(struct inode *dir,
2055                                            struct dentry *dentry,
2056                                            instantiate_t instantiate)
2057 {
2058         struct task_struct *task = get_proc_task(dir);
2059         unsigned fd = name_to_int(dentry);
2060         struct dentry *result = ERR_PTR(-ENOENT);
2061
2062         if (!task)
2063                 goto out_no_task;
2064         if (fd == ~0U)
2065                 goto out;
2066
2067         result = instantiate(dir, dentry, task, &fd);
2068 out:
2069         put_task_struct(task);
2070 out_no_task:
2071         return result;
2072 }
2073
2074 static int proc_readfd_common(struct file * filp, void * dirent,
2075                               filldir_t filldir, instantiate_t instantiate)
2076 {
2077         struct dentry *dentry = filp->f_path.dentry;
2078         struct inode *inode = dentry->d_inode;
2079         struct task_struct *p = get_proc_task(inode);
2080         unsigned int fd, ino;
2081         int retval;
2082         struct files_struct * files;
2083
2084         retval = -ENOENT;
2085         if (!p)
2086                 goto out_no_task;
2087         retval = 0;
2088
2089         fd = filp->f_pos;
2090         switch (fd) {
2091                 case 0:
2092                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
2093                                 goto out;
2094                         filp->f_pos++;
2095                 case 1:
2096                         ino = parent_ino(dentry);
2097                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
2098                                 goto out;
2099                         filp->f_pos++;
2100                 default:
2101                         files = get_files_struct(p);
2102                         if (!files)
2103                                 goto out;
2104                         rcu_read_lock();
2105                         for (fd = filp->f_pos-2;
2106                              fd < files_fdtable(files)->max_fds;
2107                              fd++, filp->f_pos++) {
2108                                 char name[PROC_NUMBUF];
2109                                 int len;
2110
2111                                 if (!fcheck_files(files, fd))
2112                                         continue;
2113                                 rcu_read_unlock();
2114
2115                                 len = snprintf(name, sizeof(name), "%d", fd);
2116                                 if (proc_fill_cache(filp, dirent, filldir,
2117                                                     name, len, instantiate,
2118                                                     p, &fd) < 0) {
2119                                         rcu_read_lock();
2120                                         break;
2121                                 }
2122                                 rcu_read_lock();
2123                         }
2124                         rcu_read_unlock();
2125                         put_files_struct(files);
2126         }
2127 out:
2128         put_task_struct(p);
2129 out_no_task:
2130         return retval;
2131 }
2132
2133 static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
2134                                     struct nameidata *nd)
2135 {
2136         return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
2137 }
2138
2139 static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
2140 {
2141         return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
2142 }
2143
2144 static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
2145                                       size_t len, loff_t *ppos)
2146 {
2147         char tmp[PROC_FDINFO_MAX];
2148         int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
2149         if (!err)
2150                 err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
2151         return err;
2152 }
2153
2154 static const struct file_operations proc_fdinfo_file_operations = {
2155         .open           = nonseekable_open,
2156         .read           = proc_fdinfo_read,
2157         .llseek         = no_llseek,
2158 };
2159
2160 static const struct file_operations proc_fd_operations = {
2161         .read           = generic_read_dir,
2162         .readdir        = proc_readfd,
2163         .llseek         = default_llseek,
2164 };
2165
2166 /*
2167  * /proc/pid/fd needs a special permission handler so that a process can still
2168  * access /proc/self/fd after it has executed a setuid().
2169  */
2170 static int proc_fd_permission(struct inode *inode, int mask, unsigned int flags)
2171 {
2172         int rv;
2173
2174         if (flags & IPERM_FLAG_RCU)
2175                 return -ECHILD;
2176         rv = generic_permission(inode, mask, flags, NULL);
2177         if (rv == 0)
2178                 return 0;
2179         if (task_pid(current) == proc_pid(inode))
2180                 rv = 0;
2181         return rv;
2182 }
2183
2184 /*
2185  * proc directories can do almost nothing..
2186  */
2187 static const struct inode_operations proc_fd_inode_operations = {
2188         .lookup         = proc_lookupfd,
2189         .permission     = proc_fd_permission,
2190         .setattr        = proc_setattr,
2191 };
2192
2193 static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
2194         struct dentry *dentry, struct task_struct *task, const void *ptr)
2195 {
2196         unsigned fd = *(unsigned *)ptr;
2197         struct inode *inode;
2198         struct proc_inode *ei;
2199         struct dentry *error = ERR_PTR(-ENOENT);
2200
2201         inode = proc_pid_make_inode(dir->i_sb, task);
2202         if (!inode)
2203                 goto out;
2204         ei = PROC_I(inode);
2205         ei->fd = fd;
2206         inode->i_mode = S_IFREG | S_IRUSR;
2207         inode->i_fop = &proc_fdinfo_file_operations;
2208         d_set_d_op(dentry, &tid_fd_dentry_operations);
2209         d_add(dentry, inode);
2210         /* Close the race of the process dying before we return the dentry */
2211         if (tid_fd_revalidate(dentry, NULL))
2212                 error = NULL;
2213
2214  out:
2215         return error;
2216 }
2217
2218 static struct dentry *proc_lookupfdinfo(struct inode *dir,
2219                                         struct dentry *dentry,
2220                                         struct nameidata *nd)
2221 {
2222         return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
2223 }
2224
2225 static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
2226 {
2227         return proc_readfd_common(filp, dirent, filldir,
2228                                   proc_fdinfo_instantiate);
2229 }
2230
2231 static const struct file_operations proc_fdinfo_operations = {
2232         .read           = generic_read_dir,
2233         .readdir        = proc_readfdinfo,
2234         .llseek         = default_llseek,
2235 };
2236
2237 /*
2238  * proc directories can do almost nothing..
2239  */
2240 static const struct inode_operations proc_fdinfo_inode_operations = {
2241         .lookup         = proc_lookupfdinfo,
2242         .setattr        = proc_setattr,
2243 };
2244
2245
2246 static struct dentry *proc_pident_instantiate(struct inode *dir,
2247         struct dentry *dentry, struct task_struct *task, const void *ptr)
2248 {
2249         const struct pid_entry *p = ptr;
2250         struct inode *inode;
2251         struct proc_inode *ei;
2252         struct dentry *error = ERR_PTR(-ENOENT);
2253
2254         inode = proc_pid_make_inode(dir->i_sb, task);
2255         if (!inode)
2256                 goto out;
2257
2258         ei = PROC_I(inode);
2259         inode->i_mode = p->mode;
2260         if (S_ISDIR(inode->i_mode))
2261                 inode->i_nlink = 2;     /* Use getattr to fix if necessary */
2262         if (p->iop)
2263                 inode->i_op = p->iop;
2264         if (p->fop)
2265                 inode->i_fop = p->fop;
2266         ei->op = p->op;
2267         d_set_d_op(dentry, &pid_dentry_operations);
2268         d_add(dentry, inode);
2269         /* Close the race of the process dying before we return the dentry */
2270         if (pid_revalidate(dentry, NULL))
2271                 error = NULL;
2272 out:
2273         return error;
2274 }
2275
2276 static struct dentry *proc_pident_lookup(struct inode *dir, 
2277                                          struct dentry *dentry,
2278                                          const struct pid_entry *ents,
2279                                          unsigned int nents)
2280 {
2281         struct dentry *error;
2282         struct task_struct *task = get_proc_task(dir);
2283         const struct pid_entry *p, *last;
2284
2285         error = ERR_PTR(-ENOENT);
2286
2287         if (!task)
2288                 goto out_no_task;
2289
2290         /*
2291          * Yes, it does not scale. And it should not. Don't add
2292          * new entries into /proc/<tgid>/ without very good reasons.
2293          */
2294         last = &ents[nents - 1];
2295         for (p = ents; p <= last; p++) {
2296                 if (p->len != dentry->d_name.len)
2297                         continue;
2298                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2299                         break;
2300         }
2301         if (p > last)
2302                 goto out;
2303
2304         error = proc_pident_instantiate(dir, dentry, task, p);
2305 out:
2306         put_task_struct(task);
2307 out_no_task:
2308         return error;
2309 }
2310
2311 static int proc_pident_fill_cache(struct file *filp, void *dirent,
2312         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2313 {
2314         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2315                                 proc_pident_instantiate, task, p);
2316 }
2317
2318 static int proc_pident_readdir(struct file *filp,
2319                 void *dirent, filldir_t filldir,
2320                 const struct pid_entry *ents, unsigned int nents)
2321 {
2322         int i;
2323         struct dentry *dentry = filp->f_path.dentry;
2324         struct inode *inode = dentry->d_inode;
2325         struct task_struct *task = get_proc_task(inode);
2326         const struct pid_entry *p, *last;
2327         ino_t ino;
2328         int ret;
2329
2330         ret = -ENOENT;
2331         if (!task)
2332                 goto out_no_task;
2333
2334         ret = 0;
2335         i = filp->f_pos;
2336         switch (i) {
2337         case 0:
2338                 ino = inode->i_ino;
2339                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2340                         goto out;
2341                 i++;
2342                 filp->f_pos++;
2343                 /* fall through */
2344         case 1:
2345                 ino = parent_ino(dentry);
2346                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2347                         goto out;
2348                 i++;
2349                 filp->f_pos++;
2350                 /* fall through */
2351         default:
2352                 i -= 2;
2353                 if (i >= nents) {
2354                         ret = 1;
2355                         goto out;
2356                 }
2357                 p = ents + i;
2358                 last = &ents[nents - 1];
2359                 while (p <= last) {
2360                         if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2361                                 goto out;
2362                         filp->f_pos++;
2363                         p++;
2364                 }
2365         }
2366
2367         ret = 1;
2368 out:
2369         put_task_struct(task);
2370 out_no_task:
2371         return ret;
2372 }
2373
2374 #ifdef CONFIG_SECURITY
2375 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2376                                   size_t count, loff_t *ppos)
2377 {
2378         struct inode * inode = file->f_path.dentry->d_inode;
2379         char *p = NULL;
2380         ssize_t length;
2381         struct task_struct *task = get_proc_task(inode);
2382
2383         if (!task)
2384                 return -ESRCH;
2385
2386         length = security_getprocattr(task,
2387                                       (char*)file->f_path.dentry->d_name.name,
2388                                       &p);
2389         put_task_struct(task);
2390         if (length > 0)
2391                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2392         kfree(p);
2393         return length;
2394 }
2395
2396 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2397                                    size_t count, loff_t *ppos)
2398 {
2399         struct inode * inode = file->f_path.dentry->d_inode;
2400         char *page;
2401         ssize_t length;
2402         struct task_struct *task = get_proc_task(inode);
2403
2404         length = -ESRCH;
2405         if (!task)
2406                 goto out_no_task;
2407         if (count > PAGE_SIZE)
2408                 count = PAGE_SIZE;
2409
2410         /* No partial writes. */
2411         length = -EINVAL;
2412         if (*ppos != 0)
2413                 goto out;
2414
2415         length = -ENOMEM;
2416         page = (char*)__get_free_page(GFP_TEMPORARY);
2417         if (!page)
2418                 goto out;
2419
2420         length = -EFAULT;
2421         if (copy_from_user(page, buf, count))
2422                 goto out_free;
2423
2424         /* Guard against adverse ptrace interaction */
2425         length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2426         if (length < 0)
2427                 goto out_free;
2428
2429         length = security_setprocattr(task,
2430                                       (char*)file->f_path.dentry->d_name.name,
2431                                       (void*)page, count);
2432         mutex_unlock(&task->signal->cred_guard_mutex);
2433 out_free:
2434         free_page((unsigned long) page);
2435 out:
2436         put_task_struct(task);
2437 out_no_task:
2438         return length;
2439 }
2440
2441 static const struct file_operations proc_pid_attr_operations = {
2442         .read           = proc_pid_attr_read,
2443         .write          = proc_pid_attr_write,
2444         .llseek         = generic_file_llseek,
2445 };
2446
2447 static const struct pid_entry attr_dir_stuff[] = {
2448         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2449         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2450         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2451         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2452         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2453         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2454 };
2455
2456 static int proc_attr_dir_readdir(struct file * filp,
2457                              void * dirent, filldir_t filldir)
2458 {
2459         return proc_pident_readdir(filp,dirent,filldir,
2460                                    attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2461 }
2462
2463 static const struct file_operations proc_attr_dir_operations = {
2464         .read           = generic_read_dir,
2465         .readdir        = proc_attr_dir_readdir,
2466         .llseek         = default_llseek,
2467 };
2468
2469 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2470                                 struct dentry *dentry, struct nameidata *nd)
2471 {
2472         return proc_pident_lookup(dir, dentry,
2473                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2474 }
2475
2476 static const struct inode_operations proc_attr_dir_inode_operations = {
2477         .lookup         = proc_attr_dir_lookup,
2478         .getattr        = pid_getattr,
2479         .setattr        = proc_setattr,
2480 };
2481
2482 #endif
2483
2484 #ifdef CONFIG_ELF_CORE
2485 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2486                                          size_t count, loff_t *ppos)
2487 {
2488         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2489         struct mm_struct *mm;
2490         char buffer[PROC_NUMBUF];
2491         size_t len;
2492         int ret;
2493
2494         if (!task)
2495                 return -ESRCH;
2496
2497         ret = 0;
2498         mm = get_task_mm(task);
2499         if (mm) {
2500                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2501                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2502                                 MMF_DUMP_FILTER_SHIFT));
2503                 mmput(mm);
2504                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2505         }
2506
2507         put_task_struct(task);
2508
2509         return ret;
2510 }
2511
2512 static ssize_t proc_coredump_filter_write(struct file *file,
2513                                           const char __user *buf,
2514                                           size_t count,
2515                                           loff_t *ppos)
2516 {
2517         struct task_struct *task;
2518         struct mm_struct *mm;
2519         char buffer[PROC_NUMBUF], *end;
2520         unsigned int val;
2521         int ret;
2522         int i;
2523         unsigned long mask;
2524
2525         ret = -EFAULT;
2526         memset(buffer, 0, sizeof(buffer));
2527         if (count > sizeof(buffer) - 1)
2528                 count = sizeof(buffer) - 1;
2529         if (copy_from_user(buffer, buf, count))
2530                 goto out_no_task;
2531
2532         ret = -EINVAL;
2533         val = (unsigned int)simple_strtoul(buffer, &end, 0);
2534         if (*end == '\n')
2535                 end++;
2536         if (end - buffer == 0)
2537                 goto out_no_task;
2538
2539         ret = -ESRCH;
2540         task = get_proc_task(file->f_dentry->d_inode);
2541         if (!task)
2542                 goto out_no_task;
2543
2544         ret = end - buffer;
2545         mm = get_task_mm(task);
2546         if (!mm)
2547                 goto out_no_mm;
2548
2549         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2550                 if (val & mask)
2551                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2552                 else
2553                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2554         }
2555
2556         mmput(mm);
2557  out_no_mm:
2558         put_task_struct(task);
2559  out_no_task:
2560         return ret;
2561 }
2562
2563 static const struct file_operations proc_coredump_filter_operations = {
2564         .read           = proc_coredump_filter_read,
2565         .write          = proc_coredump_filter_write,
2566         .llseek         = generic_file_llseek,
2567 };
2568 #endif
2569
2570 /*
2571  * /proc/self:
2572  */
2573 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2574                               int buflen)
2575 {
2576         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2577         pid_t tgid = task_tgid_nr_ns(current, ns);
2578         char tmp[PROC_NUMBUF];
2579         if (!tgid)
2580                 return -ENOENT;
2581         sprintf(tmp, "%d", tgid);
2582         return vfs_readlink(dentry,buffer,buflen,tmp);
2583 }
2584
2585 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2586 {
2587         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2588         pid_t tgid = task_tgid_nr_ns(current, ns);
2589         char *name = ERR_PTR(-ENOENT);
2590         if (tgid) {
2591                 name = __getname();
2592                 if (!name)
2593                         name = ERR_PTR(-ENOMEM);
2594                 else
2595                         sprintf(name, "%d", tgid);
2596         }
2597         nd_set_link(nd, name);
2598         return NULL;
2599 }
2600
2601 static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
2602                                 void *cookie)
2603 {
2604         char *s = nd_get_link(nd);
2605         if (!IS_ERR(s))
2606                 __putname(s);
2607 }
2608
2609 static const struct inode_operations proc_self_inode_operations = {
2610         .readlink       = proc_self_readlink,
2611         .follow_link    = proc_self_follow_link,
2612         .put_link       = proc_self_put_link,
2613 };
2614
2615 /*
2616  * proc base
2617  *
2618  * These are the directory entries in the root directory of /proc
2619  * that properly belong to the /proc filesystem, as they describe
2620  * describe something that is process related.
2621  */
2622 static const struct pid_entry proc_base_stuff[] = {
2623         NOD("self", S_IFLNK|S_IRWXUGO,
2624                 &proc_self_inode_operations, NULL, {}),
2625 };
2626
2627 static struct dentry *proc_base_instantiate(struct inode *dir,
2628         struct dentry *dentry, struct task_struct *task, const void *ptr)
2629 {
2630         const struct pid_entry *p = ptr;
2631         struct inode *inode;
2632         struct proc_inode *ei;
2633         struct dentry *error;
2634
2635         /* Allocate the inode */
2636         error = ERR_PTR(-ENOMEM);
2637         inode = new_inode(dir->i_sb);
2638         if (!inode)
2639                 goto out;
2640
2641         /* Initialize the inode */
2642         ei = PROC_I(inode);
2643         inode->i_ino = get_next_ino();
2644         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2645
2646         /*
2647          * grab the reference to the task.
2648          */
2649         ei->pid = get_task_pid(task, PIDTYPE_PID);
2650         if (!ei->pid)
2651                 goto out_iput;
2652
2653         inode->i_mode = p->mode;
2654         if (S_ISDIR(inode->i_mode))
2655                 inode->i_nlink = 2;
2656         if (S_ISLNK(inode->i_mode))
2657                 inode->i_size = 64;
2658         if (p->iop)
2659                 inode->i_op = p->iop;
2660         if (p->fop)
2661                 inode->i_fop = p->fop;
2662         ei->op = p->op;
2663         d_add(dentry, inode);
2664         error = NULL;
2665 out:
2666         return error;
2667 out_iput:
2668         iput(inode);
2669         goto out;
2670 }
2671
2672 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2673 {
2674         struct dentry *error;
2675         struct task_struct *task = get_proc_task(dir);
2676         const struct pid_entry *p, *last;
2677
2678         error = ERR_PTR(-ENOENT);
2679
2680         if (!task)
2681                 goto out_no_task;
2682
2683         /* Lookup the directory entry */
2684         last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2685         for (p = proc_base_stuff; p <= last; p++) {
2686                 if (p->len != dentry->d_name.len)
2687                         continue;
2688                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2689                         break;
2690         }
2691         if (p > last)
2692                 goto out;
2693
2694         error = proc_base_instantiate(dir, dentry, task, p);
2695
2696 out:
2697         put_task_struct(task);
2698 out_no_task:
2699         return error;
2700 }
2701
2702 static int proc_base_fill_cache(struct file *filp, void *dirent,
2703         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2704 {
2705         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2706                                 proc_base_instantiate, task, p);
2707 }
2708
2709 #ifdef CONFIG_TASK_IO_ACCOUNTING
2710 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2711 {
2712         struct task_io_accounting acct = task->ioac;
2713         unsigned long flags;
2714
2715         if (whole && lock_task_sighand(task, &flags)) {
2716                 struct task_struct *t = task;
2717
2718                 task_io_accounting_add(&acct, &task->signal->ioac);
2719                 while_each_thread(task, t)
2720                         task_io_accounting_add(&acct, &t->ioac);
2721
2722                 unlock_task_sighand(task, &flags);
2723         }
2724         return sprintf(buffer,
2725                         "rchar: %llu\n"
2726                         "wchar: %llu\n"
2727                         "syscr: %llu\n"
2728                         "syscw: %llu\n"
2729                         "read_bytes: %llu\n"
2730                         "write_bytes: %llu\n"
2731                         "cancelled_write_bytes: %llu\n",
2732                         (unsigned long long)acct.rchar,
2733                         (unsigned long long)acct.wchar,
2734                         (unsigned long long)acct.syscr,
2735                         (unsigned long long)acct.syscw,
2736                         (unsigned long long)acct.read_bytes,
2737                         (unsigned long long)acct.write_bytes,
2738                         (unsigned long long)acct.cancelled_write_bytes);
2739 }
2740
2741 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2742 {
2743         return do_io_accounting(task, buffer, 0);
2744 }
2745
2746 static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2747 {
2748         return do_io_accounting(task, buffer, 1);
2749 }
2750 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2751
2752 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2753                                 struct pid *pid, struct task_struct *task)
2754 {
2755         int err = lock_trace(task);
2756         if (!err) {
2757                 seq_printf(m, "%08x\n", task->personality);
2758                 unlock_trace(task);
2759         }
2760         return err;
2761 }
2762
2763 /*
2764  * Thread groups
2765  */
2766 static const struct file_operations proc_task_operations;
2767 static const struct inode_operations proc_task_inode_operations;
2768
2769 static const struct pid_entry tgid_base_stuff[] = {
2770         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2771         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2772         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2773         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2774 #ifdef CONFIG_NET
2775         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2776 #endif
2777         REG("environ",    S_IRUSR, proc_environ_operations),
2778         INF("auxv",       S_IRUSR, proc_pid_auxv),
2779         ONE("status",     S_IRUGO, proc_pid_status),
2780         ONE("personality", S_IRUGO, proc_pid_personality),
2781         INF("limits",     S_IRUGO, proc_pid_limits),
2782 #ifdef CONFIG_SCHED_DEBUG
2783         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2784 #endif
2785 #ifdef CONFIG_SCHED_AUTOGROUP
2786         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2787 #endif
2788         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2789 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2790         INF("syscall",    S_IRUGO, proc_pid_syscall),
2791 #endif
2792         INF("cmdline",    S_IRUGO, proc_pid_cmdline),
2793         ONE("stat",       S_IRUGO, proc_tgid_stat),
2794         ONE("statm",      S_IRUGO, proc_pid_statm),
2795         REG("maps",       S_IRUGO, proc_maps_operations),
2796 #ifdef CONFIG_NUMA
2797         REG("numa_maps",  S_IRUGO, proc_numa_maps_operations),
2798 #endif
2799         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2800         LNK("cwd",        proc_cwd_link),
2801         LNK("root",       proc_root_link),
2802         LNK("exe",        proc_exe_link),
2803         REG("mounts",     S_IRUGO, proc_mounts_operations),
2804         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2805         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2806 #ifdef CONFIG_PROC_PAGE_MONITOR
2807         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2808         REG("smaps",      S_IRUGO, proc_smaps_operations),
2809         REG("pagemap",    S_IRUGO, proc_pagemap_operations),
2810 #endif
2811 #ifdef CONFIG_SECURITY
2812         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2813 #endif
2814 #ifdef CONFIG_KALLSYMS
2815         INF("wchan",      S_IRUGO, proc_pid_wchan),
2816 #endif
2817 #ifdef CONFIG_STACKTRACE
2818         ONE("stack",      S_IRUGO, proc_pid_stack),
2819 #endif
2820 #ifdef CONFIG_SCHEDSTATS
2821         INF("schedstat",  S_IRUGO, proc_pid_schedstat),
2822 #endif
2823 #ifdef CONFIG_LATENCYTOP
2824         REG("latency",  S_IRUGO, proc_lstats_operations),
2825 #endif
2826 #ifdef CONFIG_PROC_PID_CPUSET
2827         REG("cpuset",     S_IRUGO, proc_cpuset_operations),
2828 #endif
2829 #ifdef CONFIG_CGROUPS
2830         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2831 #endif
2832         INF("oom_score",  S_IRUGO, proc_oom_score),
2833         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
2834         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2835 #ifdef CONFIG_AUDITSYSCALL
2836         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2837         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2838 #endif
2839 #ifdef CONFIG_FAULT_INJECTION
2840         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2841 #endif
2842 #ifdef CONFIG_ELF_CORE
2843         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2844 #endif
2845 #ifdef CONFIG_TASK_IO_ACCOUNTING
2846         INF("io",       S_IRUGO, proc_tgid_io_accounting),
2847 #endif
2848 #ifdef CONFIG_HARDWALL
2849         INF("hardwall",   S_IRUGO, proc_pid_hardwall),
2850 #endif
2851 };
2852
2853 static int proc_tgid_base_readdir(struct file * filp,
2854                              void * dirent, filldir_t filldir)
2855 {
2856         return proc_pident_readdir(filp,dirent,filldir,
2857                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2858 }
2859
2860 static const struct file_operations proc_tgid_base_operations = {
2861         .read           = generic_read_dir,
2862         .readdir        = proc_tgid_base_readdir,
2863         .llseek         = default_llseek,
2864 };
2865
2866 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2867         return proc_pident_lookup(dir, dentry,
2868                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2869 }
2870
2871 static const struct inode_operations proc_tgid_base_inode_operations = {
2872         .lookup         = proc_tgid_base_lookup,
2873         .getattr        = pid_getattr,
2874         .setattr        = proc_setattr,
2875 };
2876
2877 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2878 {
2879         struct dentry *dentry, *leader, *dir;
2880         char buf[PROC_NUMBUF];
2881         struct qstr name;
2882
2883         name.name = buf;
2884         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2885         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2886         if (dentry) {
2887                 shrink_dcache_parent(dentry);
2888                 d_drop(dentry);
2889                 dput(dentry);
2890         }
2891
2892         name.name = buf;
2893         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2894         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2895         if (!leader)
2896                 goto out;
2897
2898         name.name = "task";
2899         name.len = strlen(name.name);
2900         dir = d_hash_and_lookup(leader, &name);
2901         if (!dir)
2902                 goto out_put_leader;
2903
2904         name.name = buf;
2905         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2906         dentry = d_hash_and_lookup(dir, &name);
2907         if (dentry) {
2908                 shrink_dcache_parent(dentry);
2909                 d_drop(dentry);
2910                 dput(dentry);
2911         }
2912
2913         dput(dir);
2914 out_put_leader:
2915         dput(leader);
2916 out:
2917         return;
2918 }
2919
2920 /**
2921  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2922  * @task: task that should be flushed.
2923  *
2924  * When flushing dentries from proc, one needs to flush them from global
2925  * proc (proc_mnt) and from all the namespaces' procs this task was seen
2926  * in. This call is supposed to do all of this job.
2927  *
2928  * Looks in the dcache for
2929  * /proc/@pid
2930  * /proc/@tgid/task/@pid
2931  * if either directory is present flushes it and all of it'ts children
2932  * from the dcache.
2933  *
2934  * It is safe and reasonable to cache /proc entries for a task until
2935  * that task exits.  After that they just clog up the dcache with
2936  * useless entries, possibly causing useful dcache entries to be
2937  * flushed instead.  This routine is proved to flush those useless
2938  * dcache entries at process exit time.
2939  *
2940  * NOTE: This routine is just an optimization so it does not guarantee
2941  *       that no dcache entries will exist at process exit time it
2942  *       just makes it very unlikely that any will persist.
2943  */
2944
2945 void proc_flush_task(struct task_struct *task)
2946 {
2947         int i;
2948         struct pid *pid, *tgid;
2949         struct upid *upid;
2950
2951         pid = task_pid(task);
2952         tgid = task_tgid(task);
2953
2954         for (i = 0; i <= pid->level; i++) {
2955                 upid = &pid->numbers[i];
2956                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2957                                         tgid->numbers[i].nr);
2958         }
2959
2960         upid = &pid->numbers[pid->level];
2961         if (upid->nr == 1)
2962                 pid_ns_release_proc(upid->ns);
2963 }
2964
2965 static struct dentry *proc_pid_instantiate(struct inode *dir,
2966                                            struct dentry * dentry,
2967                                            struct task_struct *task, const void *ptr)
2968 {
2969         struct dentry *error = ERR_PTR(-ENOENT);
2970         struct inode *inode;
2971
2972         inode = proc_pid_make_inode(dir->i_sb, task);
2973         if (!inode)
2974                 goto out;
2975
2976         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2977         inode->i_op = &proc_tgid_base_inode_operations;
2978         inode->i_fop = &proc_tgid_base_operations;
2979         inode->i_flags|=S_IMMUTABLE;
2980
2981         inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
2982                 ARRAY_SIZE(tgid_base_stuff));
2983
2984         d_set_d_op(dentry, &pid_dentry_operations);
2985
2986         d_add(dentry, inode);
2987         /* Close the race of the process dying before we return the dentry */
2988         if (pid_revalidate(dentry, NULL))
2989                 error = NULL;
2990 out:
2991         return error;
2992 }
2993
2994 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2995 {
2996         struct dentry *result;
2997         struct task_struct *task;
2998         unsigned tgid;
2999         struct pid_namespace *ns;
3000
3001         result = proc_base_lookup(dir, dentry);
3002         if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
3003                 goto out;
3004
3005         tgid = name_to_int(dentry);
3006         if (tgid == ~0U)
3007                 goto out;
3008
3009         ns = dentry->d_sb->s_fs_info;
3010         rcu_read_lock();
3011         task = find_task_by_pid_ns(tgid, ns);
3012         if (task)
3013                 get_task_struct(task);
3014         rcu_read_unlock();
3015         if (!task)
3016                 goto out;
3017
3018         result = proc_pid_instantiate(dir, dentry, task, NULL);
3019         put_task_struct(task);
3020 out:
3021         return result;
3022 }
3023
3024 /*
3025  * Find the first task with tgid >= tgid
3026  *
3027  */
3028 struct tgid_iter {
3029         unsigned int tgid;
3030         struct task_struct *task;
3031 };
3032 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3033 {
3034         struct pid *pid;
3035
3036         if (iter.task)
3037                 put_task_struct(iter.task);
3038         rcu_read_lock();
3039 retry:
3040         iter.task = NULL;
3041         pid = find_ge_pid(iter.tgid, ns);
3042         if (pid) {
3043                 iter.tgid = pid_nr_ns(pid, ns);
3044                 iter.task = pid_task(pid, PIDTYPE_PID);
3045                 /* What we to know is if the pid we have find is the
3046                  * pid of a thread_group_leader.  Testing for task
3047                  * being a thread_group_leader is the obvious thing
3048                  * todo but there is a window when it fails, due to
3049                  * the pid transfer logic in de_thread.
3050                  *
3051                  * So we perform the straight forward test of seeing
3052                  * if the pid we have found is the pid of a thread
3053                  * group leader, and don't worry if the task we have
3054                  * found doesn't happen to be a thread group leader.
3055                  * As we don't care in the case of readdir.
3056                  */
3057                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3058                         iter.tgid += 1;
3059                         goto retry;
3060                 }
3061                 get_task_struct(iter.task);
3062         }
3063         rcu_read_unlock();
3064         return iter;
3065 }
3066
3067 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
3068
3069 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3070         struct tgid_iter iter)
3071 {
3072         char name[PROC_NUMBUF];
3073         int len = snprintf(name, sizeof(name), "%d", iter.tgid);
3074         return proc_fill_cache(filp, dirent, filldir, name, len,
3075                                 proc_pid_instantiate, iter.task, NULL);
3076 }
3077
3078 /* for the /proc/ directory itself, after non-process stuff has been done */
3079 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
3080 {
3081         unsigned int nr;
3082         struct task_struct *reaper;
3083         struct tgid_iter iter;
3084         struct pid_namespace *ns;
3085
3086         if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
3087                 goto out_no_task;
3088         nr = filp->f_pos - FIRST_PROCESS_ENTRY;
3089
3090         reaper = get_proc_task(filp->f_path.dentry->d_inode);
3091         if (!reaper)
3092                 goto out_no_task;
3093
3094         for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
3095                 const struct pid_entry *p = &proc_base_stuff[nr];
3096                 if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
3097                         goto out;
3098         }
3099
3100         ns = filp->f_dentry->d_sb->s_fs_info;
3101         iter.task = NULL;
3102         iter.tgid = filp->f_pos - TGID_OFFSET;
3103         for (iter = next_tgid(ns, iter);
3104              iter.task;
3105              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3106                 filp->f_pos = iter.tgid + TGID_OFFSET;
3107                 if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
3108                         put_task_struct(iter.task);
3109                         goto out;
3110                 }
3111         }
3112         filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
3113 out:
3114         put_task_struct(reaper);
3115 out_no_task:
3116         return 0;
3117 }
3118
3119 /*
3120  * Tasks
3121  */
3122 static const struct pid_entry tid_base_stuff[] = {
3123         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3124         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3125         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3126         REG("environ",   S_IRUSR, proc_environ_operations),
3127         INF("auxv",      S_IRUSR, proc_pid_auxv),
3128         ONE("status",    S_IRUGO, proc_pid_status),
3129         ONE("personality", S_IRUGO, proc_pid_personality),
3130         INF("limits",    S_IRUGO, proc_pid_limits),
3131 #ifdef CONFIG_SCHED_DEBUG
3132         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3133 #endif
3134         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3135 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3136         INF("syscall",   S_IRUGO, proc_pid_syscall),
3137 #endif
3138         INF("cmdline",   S_IRUGO, proc_pid_cmdline),
3139         ONE("stat",      S_IRUGO, proc_tid_stat),
3140         ONE("statm",     S_IRUGO, proc_pid_statm),
3141         REG("maps",      S_IRUGO, proc_maps_operations),
3142 #ifdef CONFIG_NUMA
3143         REG("numa_maps", S_IRUGO, proc_numa_maps_operations),
3144 #endif
3145         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3146         LNK("cwd",       proc_cwd_link),
3147         LNK("root",      proc_root_link),
3148         LNK("exe",       proc_exe_link),
3149         REG("mounts",    S_IRUGO, proc_mounts_operations),
3150         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3151 #ifdef CONFIG_PROC_PAGE_MONITOR
3152         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3153         REG("smaps",     S_IRUGO, proc_smaps_operations),
3154         REG("pagemap",    S_IRUGO, proc_pagemap_operations),
3155 #endif
3156 #ifdef CONFIG_SECURITY
3157         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3158 #endif
3159 #ifdef CONFIG_KALLSYMS
3160         INF("wchan",     S_IRUGO, proc_pid_wchan),
3161 #endif
3162 #ifdef CONFIG_STACKTRACE
3163         ONE("stack",      S_IRUGO, proc_pid_stack),
3164 #endif
3165 #ifdef CONFIG_SCHEDSTATS
3166         INF("schedstat", S_IRUGO, proc_pid_schedstat),
3167 #endif
3168 #ifdef CONFIG_LATENCYTOP
3169         REG("latency",  S_IRUGO, proc_lstats_operations),
3170 #endif
3171 #ifdef CONFIG_PROC_PID_CPUSET
3172         REG("cpuset",    S_IRUGO, proc_cpuset_operations),
3173 #endif
3174 #ifdef CONFIG_CGROUPS
3175         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3176 #endif
3177         INF("oom_score", S_IRUGO, proc_oom_score),
3178         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
3179         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3180 #ifdef CONFIG_AUDITSYSCALL
3181         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3182         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3183 #endif
3184 #ifdef CONFIG_FAULT_INJECTION
3185         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3186 #endif
3187 #ifdef CONFIG_TASK_IO_ACCOUNTING
3188         INF("io",       S_IRUGO, proc_tid_io_accounting),
3189 #endif
3190 #ifdef CONFIG_HARDWALL
3191         INF("hardwall",   S_IRUGO, proc_pid_hardwall),
3192 #endif
3193 };
3194
3195 static int proc_tid_base_readdir(struct file * filp,
3196                              void * dirent, filldir_t filldir)
3197 {
3198         return proc_pident_readdir(filp,dirent,filldir,
3199                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
3200 }
3201
3202 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
3203         return proc_pident_lookup(dir, dentry,
3204                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3205 }
3206
3207 static const struct file_operations proc_tid_base_operations = {
3208         .read           = generic_read_dir,
3209         .readdir        = proc_tid_base_readdir,
3210         .llseek         = default_llseek,
3211 };
3212
3213 static const struct inode_operations proc_tid_base_inode_operations = {
3214         .lookup         = proc_tid_base_lookup,
3215         .getattr        = pid_getattr,
3216         .setattr        = proc_setattr,
3217 };
3218
3219 static struct dentry *proc_task_instantiate(struct inode *dir,
3220         struct dentry *dentry, struct task_struct *task, const void *ptr)
3221 {
3222         struct dentry *error = ERR_PTR(-ENOENT);
3223         struct inode *inode;
3224         inode = proc_pid_make_inode(dir->i_sb, task);
3225
3226         if (!inode)
3227                 goto out;
3228         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3229         inode->i_op = &proc_tid_base_inode_operations;
3230         inode->i_fop = &proc_tid_base_operations;
3231         inode->i_flags|=S_IMMUTABLE;
3232
3233         inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
3234                 ARRAY_SIZE(tid_base_stuff));
3235
3236         d_set_d_op(dentry, &pid_dentry_operations);
3237
3238         d_add(dentry, inode);
3239         /* Close the race of the process dying before we return the dentry */
3240         if (pid_revalidate(dentry, NULL))
3241                 error = NULL;
3242 out:
3243         return error;
3244 }
3245
3246 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3247 {
3248         struct dentry *result = ERR_PTR(-ENOENT);
3249         struct task_struct *task;
3250         struct task_struct *leader = get_proc_task(dir);
3251         unsigned tid;
3252         struct pid_namespace *ns;
3253
3254         if (!leader)
3255                 goto out_no_task;
3256
3257         tid = name_to_int(dentry);
3258         if (tid == ~0U)
3259                 goto out;
3260
3261         ns = dentry->d_sb->s_fs_info;
3262         rcu_read_lock();
3263         task = find_task_by_pid_ns(tid, ns);
3264         if (task)
3265                 get_task_struct(task);
3266         rcu_read_unlock();
3267         if (!task)
3268                 goto out;
3269         if (!same_thread_group(leader, task))
3270                 goto out_drop_task;
3271
3272         result = proc_task_instantiate(dir, dentry, task, NULL);
3273 out_drop_task:
3274         put_task_struct(task);
3275 out:
3276         put_task_struct(leader);
3277 out_no_task:
3278         return result;
3279 }
3280
3281 /*
3282  * Find the first tid of a thread group to return to user space.
3283  *
3284  * Usually this is just the thread group leader, but if the users
3285  * buffer was too small or there was a seek into the middle of the
3286  * directory we have more work todo.
3287  *
3288  * In the case of a short read we start with find_task_by_pid.
3289  *
3290  * In the case of a seek we start with the leader and walk nr
3291  * threads past it.
3292  */
3293 static struct task_struct *first_tid(struct task_struct *leader,
3294                 int tid, int nr, struct pid_namespace *ns)
3295 {
3296         struct task_struct *pos;
3297
3298         rcu_read_lock();
3299         /* Attempt to start with the pid of a thread */
3300         if (tid && (nr > 0)) {
3301                 pos = find_task_by_pid_ns(tid, ns);
3302                 if (pos && (pos->group_leader == leader))
3303                         goto found;
3304         }
3305
3306         /* If nr exceeds the number of threads there is nothing todo */
3307         pos = NULL;
3308         if (nr && nr >= get_nr_threads(leader))
3309                 goto out;
3310
3311         /* If we haven't found our starting place yet start
3312          * with the leader and walk nr threads forward.
3313          */
3314         for (pos = leader; nr > 0; --nr) {
3315                 pos = next_thread(pos);
3316                 if (pos == leader) {
3317                         pos = NULL;
3318                         goto out;
3319                 }
3320         }
3321 found:
3322         get_task_struct(pos);
3323 out:
3324         rcu_read_unlock();
3325         return pos;
3326 }
3327
3328 /*
3329  * Find the next thread in the thread list.
3330  * Return NULL if there is an error or no next thread.
3331  *
3332  * The reference to the input task_struct is released.
3333  */
3334 static struct task_struct *next_tid(struct task_struct *start)
3335 {
3336         struct task_struct *pos = NULL;
3337         rcu_read_lock();
3338         if (pid_alive(start)) {
3339                 pos = next_thread(start);
3340                 if (thread_group_leader(pos))
3341                         pos = NULL;
3342                 else
3343                         get_task_struct(pos);
3344         }
3345         rcu_read_unlock();
3346         put_task_struct(start);
3347         return pos;
3348 }
3349
3350 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3351         struct task_struct *task, int tid)
3352 {
3353         char name[PROC_NUMBUF];
3354         int len = snprintf(name, sizeof(name), "%d", tid);
3355         return proc_fill_cache(filp, dirent, filldir, name, len,
3356                                 proc_task_instantiate, task, NULL);
3357 }
3358
3359 /* for the /proc/TGID/task/ directories */
3360 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3361 {
3362         struct dentry *dentry = filp->f_path.dentry;
3363         struct inode *inode = dentry->d_inode;
3364         struct task_struct *leader = NULL;
3365         struct task_struct *task;
3366         int retval = -ENOENT;
3367         ino_t ino;
3368         int tid;
3369         struct pid_namespace *ns;
3370
3371         task = get_proc_task(inode);
3372         if (!task)
3373                 goto out_no_task;
3374         rcu_read_lock();
3375         if (pid_alive(task)) {
3376                 leader = task->group_leader;
3377                 get_task_struct(leader);