oom_ajd: don't use WARN_ONCE, just use printk_once
[linux-2.6.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 = (ptrace_parent(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->m.poll_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, please use /proc/%d/oom_score_adj instead.\n",
1122                   current->comm, task_pid_nr(current), task_pid_nr(task),
1123                   task_pid_nr(task));
1124         task->signal->oom_adj = oom_adjust;
1125         /*
1126          * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
1127          * value is always attainable.
1128          */
1129         if (task->signal->oom_adj == OOM_ADJUST_MAX)
1130                 task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX;
1131         else
1132                 task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
1133                                                                 -OOM_DISABLE;
1134 err_sighand:
1135         unlock_task_sighand(task, &flags);
1136 err_task_lock:
1137         task_unlock(task);
1138         put_task_struct(task);
1139 out:
1140         return err < 0 ? err : count;
1141 }
1142
1143 static const struct file_operations proc_oom_adjust_operations = {
1144         .read           = oom_adjust_read,
1145         .write          = oom_adjust_write,
1146         .llseek         = generic_file_llseek,
1147 };
1148
1149 static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
1150                                         size_t count, loff_t *ppos)
1151 {
1152         struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
1153         char buffer[PROC_NUMBUF];
1154         int oom_score_adj = OOM_SCORE_ADJ_MIN;
1155         unsigned long flags;
1156         size_t len;
1157
1158         if (!task)
1159                 return -ESRCH;
1160         if (lock_task_sighand(task, &flags)) {
1161                 oom_score_adj = task->signal->oom_score_adj;
1162                 unlock_task_sighand(task, &flags);
1163         }
1164         put_task_struct(task);
1165         len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj);
1166         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1167 }
1168
1169 static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
1170                                         size_t count, loff_t *ppos)
1171 {
1172         struct task_struct *task;
1173         char buffer[PROC_NUMBUF];
1174         unsigned long flags;
1175         int oom_score_adj;
1176         int err;
1177
1178         memset(buffer, 0, sizeof(buffer));
1179         if (count > sizeof(buffer) - 1)
1180                 count = sizeof(buffer) - 1;
1181         if (copy_from_user(buffer, buf, count)) {
1182                 err = -EFAULT;
1183                 goto out;
1184         }
1185
1186         err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
1187         if (err)
1188                 goto out;
1189         if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
1190                         oom_score_adj > OOM_SCORE_ADJ_MAX) {
1191                 err = -EINVAL;
1192                 goto out;
1193         }
1194
1195         task = get_proc_task(file->f_path.dentry->d_inode);
1196         if (!task) {
1197                 err = -ESRCH;
1198                 goto out;
1199         }
1200
1201         task_lock(task);
1202         if (!task->mm) {
1203                 err = -EINVAL;
1204                 goto err_task_lock;
1205         }
1206
1207         if (!lock_task_sighand(task, &flags)) {
1208                 err = -ESRCH;
1209                 goto err_task_lock;
1210         }
1211
1212         if (oom_score_adj < task->signal->oom_score_adj_min &&
1213                         !capable(CAP_SYS_RESOURCE)) {
1214                 err = -EACCES;
1215                 goto err_sighand;
1216         }
1217
1218         if (oom_score_adj != task->signal->oom_score_adj) {
1219                 if (oom_score_adj == OOM_SCORE_ADJ_MIN)
1220                         atomic_inc(&task->mm->oom_disable_count);
1221                 if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1222                         atomic_dec(&task->mm->oom_disable_count);
1223         }
1224         task->signal->oom_score_adj = oom_score_adj;
1225         if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
1226                 task->signal->oom_score_adj_min = oom_score_adj;
1227         /*
1228          * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
1229          * always attainable.
1230          */
1231         if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
1232                 task->signal->oom_adj = OOM_DISABLE;
1233         else
1234                 task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
1235                                                         OOM_SCORE_ADJ_MAX;
1236 err_sighand:
1237         unlock_task_sighand(task, &flags);
1238 err_task_lock:
1239         task_unlock(task);
1240         put_task_struct(task);
1241 out:
1242         return err < 0 ? err : count;
1243 }
1244
1245 static const struct file_operations proc_oom_score_adj_operations = {
1246         .read           = oom_score_adj_read,
1247         .write          = oom_score_adj_write,
1248         .llseek         = default_llseek,
1249 };
1250
1251 #ifdef CONFIG_AUDITSYSCALL
1252 #define TMPBUFLEN 21
1253 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1254                                   size_t count, loff_t *ppos)
1255 {
1256         struct inode * inode = file->f_path.dentry->d_inode;
1257         struct task_struct *task = get_proc_task(inode);
1258         ssize_t length;
1259         char tmpbuf[TMPBUFLEN];
1260
1261         if (!task)
1262                 return -ESRCH;
1263         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1264                                 audit_get_loginuid(task));
1265         put_task_struct(task);
1266         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1267 }
1268
1269 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1270                                    size_t count, loff_t *ppos)
1271 {
1272         struct inode * inode = file->f_path.dentry->d_inode;
1273         char *page, *tmp;
1274         ssize_t length;
1275         uid_t loginuid;
1276
1277         if (!capable(CAP_AUDIT_CONTROL))
1278                 return -EPERM;
1279
1280         rcu_read_lock();
1281         if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
1282                 rcu_read_unlock();
1283                 return -EPERM;
1284         }
1285         rcu_read_unlock();
1286
1287         if (count >= PAGE_SIZE)
1288                 count = PAGE_SIZE - 1;
1289
1290         if (*ppos != 0) {
1291                 /* No partial writes. */
1292                 return -EINVAL;
1293         }
1294         page = (char*)__get_free_page(GFP_TEMPORARY);
1295         if (!page)
1296                 return -ENOMEM;
1297         length = -EFAULT;
1298         if (copy_from_user(page, buf, count))
1299                 goto out_free_page;
1300
1301         page[count] = '\0';
1302         loginuid = simple_strtoul(page, &tmp, 10);
1303         if (tmp == page) {
1304                 length = -EINVAL;
1305                 goto out_free_page;
1306
1307         }
1308         length = audit_set_loginuid(current, loginuid);
1309         if (likely(length == 0))
1310                 length = count;
1311
1312 out_free_page:
1313         free_page((unsigned long) page);
1314         return length;
1315 }
1316
1317 static const struct file_operations proc_loginuid_operations = {
1318         .read           = proc_loginuid_read,
1319         .write          = proc_loginuid_write,
1320         .llseek         = generic_file_llseek,
1321 };
1322
1323 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1324                                   size_t count, loff_t *ppos)
1325 {
1326         struct inode * inode = file->f_path.dentry->d_inode;
1327         struct task_struct *task = get_proc_task(inode);
1328         ssize_t length;
1329         char tmpbuf[TMPBUFLEN];
1330
1331         if (!task)
1332                 return -ESRCH;
1333         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1334                                 audit_get_sessionid(task));
1335         put_task_struct(task);
1336         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1337 }
1338
1339 static const struct file_operations proc_sessionid_operations = {
1340         .read           = proc_sessionid_read,
1341         .llseek         = generic_file_llseek,
1342 };
1343 #endif
1344
1345 #ifdef CONFIG_FAULT_INJECTION
1346 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1347                                       size_t count, loff_t *ppos)
1348 {
1349         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1350         char buffer[PROC_NUMBUF];
1351         size_t len;
1352         int make_it_fail;
1353
1354         if (!task)
1355                 return -ESRCH;
1356         make_it_fail = task->make_it_fail;
1357         put_task_struct(task);
1358
1359         len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1360
1361         return simple_read_from_buffer(buf, count, ppos, buffer, len);
1362 }
1363
1364 static ssize_t proc_fault_inject_write(struct file * file,
1365                         const char __user * buf, size_t count, loff_t *ppos)
1366 {
1367         struct task_struct *task;
1368         char buffer[PROC_NUMBUF], *end;
1369         int make_it_fail;
1370
1371         if (!capable(CAP_SYS_RESOURCE))
1372                 return -EPERM;
1373         memset(buffer, 0, sizeof(buffer));
1374         if (count > sizeof(buffer) - 1)
1375                 count = sizeof(buffer) - 1;
1376         if (copy_from_user(buffer, buf, count))
1377                 return -EFAULT;
1378         make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
1379         if (*end)
1380                 return -EINVAL;
1381         task = get_proc_task(file->f_dentry->d_inode);
1382         if (!task)
1383                 return -ESRCH;
1384         task->make_it_fail = make_it_fail;
1385         put_task_struct(task);
1386
1387         return count;
1388 }
1389
1390 static const struct file_operations proc_fault_inject_operations = {
1391         .read           = proc_fault_inject_read,
1392         .write          = proc_fault_inject_write,
1393         .llseek         = generic_file_llseek,
1394 };
1395 #endif
1396
1397
1398 #ifdef CONFIG_SCHED_DEBUG
1399 /*
1400  * Print out various scheduling related per-task fields:
1401  */
1402 static int sched_show(struct seq_file *m, void *v)
1403 {
1404         struct inode *inode = m->private;
1405         struct task_struct *p;
1406
1407         p = get_proc_task(inode);
1408         if (!p)
1409                 return -ESRCH;
1410         proc_sched_show_task(p, m);
1411
1412         put_task_struct(p);
1413
1414         return 0;
1415 }
1416
1417 static ssize_t
1418 sched_write(struct file *file, const char __user *buf,
1419             size_t count, loff_t *offset)
1420 {
1421         struct inode *inode = file->f_path.dentry->d_inode;
1422         struct task_struct *p;
1423
1424         p = get_proc_task(inode);
1425         if (!p)
1426                 return -ESRCH;
1427         proc_sched_set_task(p);
1428
1429         put_task_struct(p);
1430
1431         return count;
1432 }
1433
1434 static int sched_open(struct inode *inode, struct file *filp)
1435 {
1436         return single_open(filp, sched_show, inode);
1437 }
1438
1439 static const struct file_operations proc_pid_sched_operations = {
1440         .open           = sched_open,
1441         .read           = seq_read,
1442         .write          = sched_write,
1443         .llseek         = seq_lseek,
1444         .release        = single_release,
1445 };
1446
1447 #endif
1448
1449 #ifdef CONFIG_SCHED_AUTOGROUP
1450 /*
1451  * Print out autogroup related information:
1452  */
1453 static int sched_autogroup_show(struct seq_file *m, void *v)
1454 {
1455         struct inode *inode = m->private;
1456         struct task_struct *p;
1457
1458         p = get_proc_task(inode);
1459         if (!p)
1460                 return -ESRCH;
1461         proc_sched_autogroup_show_task(p, m);
1462
1463         put_task_struct(p);
1464
1465         return 0;
1466 }
1467
1468 static ssize_t
1469 sched_autogroup_write(struct file *file, const char __user *buf,
1470             size_t count, loff_t *offset)
1471 {
1472         struct inode *inode = file->f_path.dentry->d_inode;
1473         struct task_struct *p;
1474         char buffer[PROC_NUMBUF];
1475         int nice;
1476         int err;
1477
1478         memset(buffer, 0, sizeof(buffer));
1479         if (count > sizeof(buffer) - 1)
1480                 count = sizeof(buffer) - 1;
1481         if (copy_from_user(buffer, buf, count))
1482                 return -EFAULT;
1483
1484         err = kstrtoint(strstrip(buffer), 0, &nice);
1485         if (err < 0)
1486                 return err;
1487
1488         p = get_proc_task(inode);
1489         if (!p)
1490                 return -ESRCH;
1491
1492         err = nice;
1493         err = proc_sched_autogroup_set_nice(p, &err);
1494         if (err)
1495                 count = err;
1496
1497         put_task_struct(p);
1498
1499         return count;
1500 }
1501
1502 static int sched_autogroup_open(struct inode *inode, struct file *filp)
1503 {
1504         int ret;
1505
1506         ret = single_open(filp, sched_autogroup_show, NULL);
1507         if (!ret) {
1508                 struct seq_file *m = filp->private_data;
1509
1510                 m->private = inode;
1511         }
1512         return ret;
1513 }
1514
1515 static const struct file_operations proc_pid_sched_autogroup_operations = {
1516         .open           = sched_autogroup_open,
1517         .read           = seq_read,
1518         .write          = sched_autogroup_write,
1519         .llseek         = seq_lseek,
1520         .release        = single_release,
1521 };
1522
1523 #endif /* CONFIG_SCHED_AUTOGROUP */
1524
1525 static ssize_t comm_write(struct file *file, const char __user *buf,
1526                                 size_t count, loff_t *offset)
1527 {
1528         struct inode *inode = file->f_path.dentry->d_inode;
1529         struct task_struct *p;
1530         char buffer[TASK_COMM_LEN];
1531
1532         memset(buffer, 0, sizeof(buffer));
1533         if (count > sizeof(buffer) - 1)
1534                 count = sizeof(buffer) - 1;
1535         if (copy_from_user(buffer, buf, count))
1536                 return -EFAULT;
1537
1538         p = get_proc_task(inode);
1539         if (!p)
1540                 return -ESRCH;
1541
1542         if (same_thread_group(current, p))
1543                 set_task_comm(p, buffer);
1544         else
1545                 count = -EINVAL;
1546
1547         put_task_struct(p);
1548
1549         return count;
1550 }
1551
1552 static int comm_show(struct seq_file *m, void *v)
1553 {
1554         struct inode *inode = m->private;
1555         struct task_struct *p;
1556
1557         p = get_proc_task(inode);
1558         if (!p)
1559                 return -ESRCH;
1560
1561         task_lock(p);
1562         seq_printf(m, "%s\n", p->comm);
1563         task_unlock(p);
1564
1565         put_task_struct(p);
1566
1567         return 0;
1568 }
1569
1570 static int comm_open(struct inode *inode, struct file *filp)
1571 {
1572         return single_open(filp, comm_show, inode);
1573 }
1574
1575 static const struct file_operations proc_pid_set_comm_operations = {
1576         .open           = comm_open,
1577         .read           = seq_read,
1578         .write          = comm_write,
1579         .llseek         = seq_lseek,
1580         .release        = single_release,
1581 };
1582
1583 static int proc_exe_link(struct inode *inode, struct path *exe_path)
1584 {
1585         struct task_struct *task;
1586         struct mm_struct *mm;
1587         struct file *exe_file;
1588
1589         task = get_proc_task(inode);
1590         if (!task)
1591                 return -ENOENT;
1592         mm = get_task_mm(task);
1593         put_task_struct(task);
1594         if (!mm)
1595                 return -ENOENT;
1596         exe_file = get_mm_exe_file(mm);
1597         mmput(mm);
1598         if (exe_file) {
1599                 *exe_path = exe_file->f_path;
1600                 path_get(&exe_file->f_path);
1601                 fput(exe_file);
1602                 return 0;
1603         } else
1604                 return -ENOENT;
1605 }
1606
1607 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1608 {
1609         struct inode *inode = dentry->d_inode;
1610         int error = -EACCES;
1611
1612         /* We don't need a base pointer in the /proc filesystem */
1613         path_put(&nd->path);
1614
1615         /* Are we allowed to snoop on the tasks file descriptors? */
1616         if (!proc_fd_access_allowed(inode))
1617                 goto out;
1618
1619         error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1620 out:
1621         return ERR_PTR(error);
1622 }
1623
1624 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1625 {
1626         char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1627         char *pathname;
1628         int len;
1629
1630         if (!tmp)
1631                 return -ENOMEM;
1632
1633         pathname = d_path(path, tmp, PAGE_SIZE);
1634         len = PTR_ERR(pathname);
1635         if (IS_ERR(pathname))
1636                 goto out;
1637         len = tmp + PAGE_SIZE - 1 - pathname;
1638
1639         if (len > buflen)
1640                 len = buflen;
1641         if (copy_to_user(buffer, pathname, len))
1642                 len = -EFAULT;
1643  out:
1644         free_page((unsigned long)tmp);
1645         return len;
1646 }
1647
1648 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1649 {
1650         int error = -EACCES;
1651         struct inode *inode = dentry->d_inode;
1652         struct path path;
1653
1654         /* Are we allowed to snoop on the tasks file descriptors? */
1655         if (!proc_fd_access_allowed(inode))
1656                 goto out;
1657
1658         error = PROC_I(inode)->op.proc_get_link(inode, &path);
1659         if (error)
1660                 goto out;
1661
1662         error = do_proc_readlink(&path, buffer, buflen);
1663         path_put(&path);
1664 out:
1665         return error;
1666 }
1667
1668 static const struct inode_operations proc_pid_link_inode_operations = {
1669         .readlink       = proc_pid_readlink,
1670         .follow_link    = proc_pid_follow_link,
1671         .setattr        = proc_setattr,
1672 };
1673
1674
1675 /* building an inode */
1676
1677 static int task_dumpable(struct task_struct *task)
1678 {
1679         int dumpable = 0;
1680         struct mm_struct *mm;
1681
1682         task_lock(task);
1683         mm = task->mm;
1684         if (mm)
1685                 dumpable = get_dumpable(mm);
1686         task_unlock(task);
1687         if(dumpable == 1)
1688                 return 1;
1689         return 0;
1690 }
1691
1692 struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1693 {
1694         struct inode * inode;
1695         struct proc_inode *ei;
1696         const struct cred *cred;
1697
1698         /* We need a new inode */
1699
1700         inode = new_inode(sb);
1701         if (!inode)
1702                 goto out;
1703
1704         /* Common stuff */
1705         ei = PROC_I(inode);
1706         inode->i_ino = get_next_ino();
1707         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1708         inode->i_op = &proc_def_inode_operations;
1709
1710         /*
1711          * grab the reference to task.
1712          */
1713         ei->pid = get_task_pid(task, PIDTYPE_PID);
1714         if (!ei->pid)
1715                 goto out_unlock;
1716
1717         if (task_dumpable(task)) {
1718                 rcu_read_lock();
1719                 cred = __task_cred(task);
1720                 inode->i_uid = cred->euid;
1721                 inode->i_gid = cred->egid;
1722                 rcu_read_unlock();
1723         }
1724         security_task_to_inode(task, inode);
1725
1726 out:
1727         return inode;
1728
1729 out_unlock:
1730         iput(inode);
1731         return NULL;
1732 }
1733
1734 int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1735 {
1736         struct inode *inode = dentry->d_inode;
1737         struct task_struct *task;
1738         const struct cred *cred;
1739
1740         generic_fillattr(inode, stat);
1741
1742         rcu_read_lock();
1743         stat->uid = 0;
1744         stat->gid = 0;
1745         task = pid_task(proc_pid(inode), PIDTYPE_PID);
1746         if (task) {
1747                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1748                     task_dumpable(task)) {
1749                         cred = __task_cred(task);
1750                         stat->uid = cred->euid;
1751                         stat->gid = cred->egid;
1752                 }
1753         }
1754         rcu_read_unlock();
1755         return 0;
1756 }
1757
1758 /* dentry stuff */
1759
1760 /*
1761  *      Exceptional case: normally we are not allowed to unhash a busy
1762  * directory. In this case, however, we can do it - no aliasing problems
1763  * due to the way we treat inodes.
1764  *
1765  * Rewrite the inode's ownerships here because the owning task may have
1766  * performed a setuid(), etc.
1767  *
1768  * Before the /proc/pid/status file was created the only way to read
1769  * the effective uid of a /process was to stat /proc/pid.  Reading
1770  * /proc/pid/status is slow enough that procps and other packages
1771  * kept stating /proc/pid.  To keep the rules in /proc simple I have
1772  * made this apply to all per process world readable and executable
1773  * directories.
1774  */
1775 int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1776 {
1777         struct inode *inode;
1778         struct task_struct *task;
1779         const struct cred *cred;
1780
1781         if (nd && nd->flags & LOOKUP_RCU)
1782                 return -ECHILD;
1783
1784         inode = dentry->d_inode;
1785         task = get_proc_task(inode);
1786
1787         if (task) {
1788                 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1789                     task_dumpable(task)) {
1790                         rcu_read_lock();
1791                         cred = __task_cred(task);
1792                         inode->i_uid = cred->euid;
1793                         inode->i_gid = cred->egid;
1794                         rcu_read_unlock();
1795                 } else {
1796                         inode->i_uid = 0;
1797                         inode->i_gid = 0;
1798                 }
1799                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1800                 security_task_to_inode(task, inode);
1801                 put_task_struct(task);
1802                 return 1;
1803         }
1804         d_drop(dentry);
1805         return 0;
1806 }
1807
1808 static int pid_delete_dentry(const struct dentry * dentry)
1809 {
1810         /* Is the task we represent dead?
1811          * If so, then don't put the dentry on the lru list,
1812          * kill it immediately.
1813          */
1814         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1815 }
1816
1817 const struct dentry_operations pid_dentry_operations =
1818 {
1819         .d_revalidate   = pid_revalidate,
1820         .d_delete       = pid_delete_dentry,
1821 };
1822
1823 /* Lookups */
1824
1825 /*
1826  * Fill a directory entry.
1827  *
1828  * If possible create the dcache entry and derive our inode number and
1829  * file type from dcache entry.
1830  *
1831  * Since all of the proc inode numbers are dynamically generated, the inode
1832  * numbers do not exist until the inode is cache.  This means creating the
1833  * the dcache entry in readdir is necessary to keep the inode numbers
1834  * reported by readdir in sync with the inode numbers reported
1835  * by stat.
1836  */
1837 int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1838         const char *name, int len,
1839         instantiate_t instantiate, struct task_struct *task, const void *ptr)
1840 {
1841         struct dentry *child, *dir = filp->f_path.dentry;
1842         struct inode *inode;
1843         struct qstr qname;
1844         ino_t ino = 0;
1845         unsigned type = DT_UNKNOWN;
1846
1847         qname.name = name;
1848         qname.len  = len;
1849         qname.hash = full_name_hash(name, len);
1850
1851         child = d_lookup(dir, &qname);
1852         if (!child) {
1853                 struct dentry *new;
1854                 new = d_alloc(dir, &qname);
1855                 if (new) {
1856                         child = instantiate(dir->d_inode, new, task, ptr);
1857                         if (child)
1858                                 dput(new);
1859                         else
1860                                 child = new;
1861                 }
1862         }
1863         if (!child || IS_ERR(child) || !child->d_inode)
1864                 goto end_instantiate;
1865         inode = child->d_inode;
1866         if (inode) {
1867                 ino = inode->i_ino;
1868                 type = inode->i_mode >> 12;
1869         }
1870         dput(child);
1871 end_instantiate:
1872         if (!ino)
1873                 ino = find_inode_number(dir, &qname);
1874         if (!ino)
1875                 ino = 1;
1876         return filldir(dirent, name, len, filp->f_pos, ino, type);
1877 }
1878
1879 static unsigned name_to_int(struct dentry *dentry)
1880 {
1881         const char *name = dentry->d_name.name;
1882         int len = dentry->d_name.len;
1883         unsigned n = 0;
1884
1885         if (len > 1 && *name == '0')
1886                 goto out;
1887         while (len-- > 0) {
1888                 unsigned c = *name++ - '0';
1889                 if (c > 9)
1890                         goto out;
1891                 if (n >= (~0U-9)/10)
1892                         goto out;
1893                 n *= 10;
1894                 n += c;
1895         }
1896         return n;
1897 out:
1898         return ~0U;
1899 }
1900
1901 #define PROC_FDINFO_MAX 64
1902
1903 static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1904 {
1905         struct task_struct *task = get_proc_task(inode);
1906         struct files_struct *files = NULL;
1907         struct file *file;
1908         int fd = proc_fd(inode);
1909
1910         if (task) {
1911                 files = get_files_struct(task);
1912                 put_task_struct(task);
1913         }
1914         if (files) {
1915                 /*
1916                  * We are not taking a ref to the file structure, so we must
1917                  * hold ->file_lock.
1918                  */
1919                 spin_lock(&files->file_lock);
1920                 file = fcheck_files(files, fd);
1921                 if (file) {
1922                         if (path) {
1923                                 *path = file->f_path;
1924                                 path_get(&file->f_path);
1925                         }
1926                         if (info)
1927                                 snprintf(info, PROC_FDINFO_MAX,
1928                                          "pos:\t%lli\n"
1929                                          "flags:\t0%o\n",
1930                                          (long long) file->f_pos,
1931                                          file->f_flags);
1932                         spin_unlock(&files->file_lock);
1933                         put_files_struct(files);
1934                         return 0;
1935                 }
1936                 spin_unlock(&files->file_lock);
1937                 put_files_struct(files);
1938         }
1939         return -ENOENT;
1940 }
1941
1942 static int proc_fd_link(struct inode *inode, struct path *path)
1943 {
1944         return proc_fd_info(inode, path, NULL);
1945 }
1946
1947 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1948 {
1949         struct inode *inode;
1950         struct task_struct *task;
1951         int fd;
1952         struct files_struct *files;
1953         const struct cred *cred;
1954
1955         if (nd && nd->flags & LOOKUP_RCU)
1956                 return -ECHILD;
1957
1958         inode = dentry->d_inode;
1959         task = get_proc_task(inode);
1960         fd = proc_fd(inode);
1961
1962         if (task) {
1963                 files = get_files_struct(task);
1964                 if (files) {
1965                         rcu_read_lock();
1966                         if (fcheck_files(files, fd)) {
1967                                 rcu_read_unlock();
1968                                 put_files_struct(files);
1969                                 if (task_dumpable(task)) {
1970                                         rcu_read_lock();
1971                                         cred = __task_cred(task);
1972                                         inode->i_uid = cred->euid;
1973                                         inode->i_gid = cred->egid;
1974                                         rcu_read_unlock();
1975                                 } else {
1976                                         inode->i_uid = 0;
1977                                         inode->i_gid = 0;
1978                                 }
1979                                 inode->i_mode &= ~(S_ISUID | S_ISGID);
1980                                 security_task_to_inode(task, inode);
1981                                 put_task_struct(task);
1982                                 return 1;
1983                         }
1984                         rcu_read_unlock();
1985                         put_files_struct(files);
1986                 }
1987                 put_task_struct(task);
1988         }
1989         d_drop(dentry);
1990         return 0;
1991 }
1992
1993 static const struct dentry_operations tid_fd_dentry_operations =
1994 {
1995         .d_revalidate   = tid_fd_revalidate,
1996         .d_delete       = pid_delete_dentry,
1997 };
1998
1999 static struct dentry *proc_fd_instantiate(struct inode *dir,
2000         struct dentry *dentry, struct task_struct *task, const void *ptr)
2001 {
2002         unsigned fd = *(const unsigned *)ptr;
2003         struct file *file;
2004         struct files_struct *files;
2005         struct inode *inode;
2006         struct proc_inode *ei;
2007         struct dentry *error = ERR_PTR(-ENOENT);
2008
2009         inode = proc_pid_make_inode(dir->i_sb, task);
2010         if (!inode)
2011                 goto out;
2012         ei = PROC_I(inode);
2013         ei->fd = fd;
2014         files = get_files_struct(task);
2015         if (!files)
2016                 goto out_iput;
2017         inode->i_mode = S_IFLNK;
2018
2019         /*
2020          * We are not taking a ref to the file structure, so we must
2021          * hold ->file_lock.
2022          */
2023         spin_lock(&files->file_lock);
2024         file = fcheck_files(files, fd);
2025         if (!file)
2026                 goto out_unlock;
2027         if (file->f_mode & FMODE_READ)
2028                 inode->i_mode |= S_IRUSR | S_IXUSR;
2029         if (file->f_mode & FMODE_WRITE)
2030                 inode->i_mode |= S_IWUSR | S_IXUSR;
2031         spin_unlock(&files->file_lock);
2032         put_files_struct(files);
2033
2034         inode->i_op = &proc_pid_link_inode_operations;
2035         inode->i_size = 64;
2036         ei->op.proc_get_link = proc_fd_link;
2037         d_set_d_op(dentry, &tid_fd_dentry_operations);
2038         d_add(dentry, inode);
2039         /* Close the race of the process dying before we return the dentry */
2040         if (tid_fd_revalidate(dentry, NULL))
2041                 error = NULL;
2042
2043  out:
2044         return error;
2045 out_unlock:
2046         spin_unlock(&files->file_lock);
2047         put_files_struct(files);
2048 out_iput:
2049         iput(inode);
2050         goto out;
2051 }
2052
2053 static struct dentry *proc_lookupfd_common(struct inode *dir,
2054                                            struct dentry *dentry,
2055                                            instantiate_t instantiate)
2056 {
2057         struct task_struct *task = get_proc_task(dir);
2058         unsigned fd = name_to_int(dentry);
2059         struct dentry *result = ERR_PTR(-ENOENT);
2060
2061         if (!task)
2062                 goto out_no_task;
2063         if (fd == ~0U)
2064                 goto out;
2065
2066         result = instantiate(dir, dentry, task, &fd);
2067 out:
2068         put_task_struct(task);
2069 out_no_task:
2070         return result;
2071 }
2072
2073 static int proc_readfd_common(struct file * filp, void * dirent,
2074                               filldir_t filldir, instantiate_t instantiate)
2075 {
2076         struct dentry *dentry = filp->f_path.dentry;
2077         struct inode *inode = dentry->d_inode;
2078         struct task_struct *p = get_proc_task(inode);
2079         unsigned int fd, ino;
2080         int retval;
2081         struct files_struct * files;
2082
2083         retval = -ENOENT;
2084         if (!p)
2085                 goto out_no_task;
2086         retval = 0;
2087
2088         fd = filp->f_pos;
2089         switch (fd) {
2090                 case 0:
2091                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
2092                                 goto out;
2093                         filp->f_pos++;
2094                 case 1:
2095                         ino = parent_ino(dentry);
2096                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
2097                                 goto out;
2098                         filp->f_pos++;
2099                 default:
2100                         files = get_files_struct(p);
2101                         if (!files)
2102                                 goto out;
2103                         rcu_read_lock();
2104                         for (fd = filp->f_pos-2;
2105                              fd < files_fdtable(files)->max_fds;
2106                              fd++, filp->f_pos++) {
2107                                 char name[PROC_NUMBUF];
2108                                 int len;
2109
2110                                 if (!fcheck_files(files, fd))
2111                                         continue;
2112                                 rcu_read_unlock();
2113
2114                                 len = snprintf(name, sizeof(name), "%d", fd);
2115                                 if (proc_fill_cache(filp, dirent, filldir,
2116                                                     name, len, instantiate,
2117                                                     p, &fd) < 0) {
2118                                         rcu_read_lock();
2119                                         break;
2120                                 }
2121                                 rcu_read_lock();
2122                         }
2123                         rcu_read_unlock();
2124                         put_files_struct(files);
2125         }
2126 out:
2127         put_task_struct(p);
2128 out_no_task:
2129         return retval;
2130 }
2131
2132 static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
2133                                     struct nameidata *nd)
2134 {
2135         return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
2136 }
2137
2138 static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
2139 {
2140         return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
2141 }
2142
2143 static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
2144                                       size_t len, loff_t *ppos)
2145 {
2146         char tmp[PROC_FDINFO_MAX];
2147         int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
2148         if (!err)
2149                 err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
2150         return err;
2151 }
2152
2153 static const struct file_operations proc_fdinfo_file_operations = {
2154         .open           = nonseekable_open,
2155         .read           = proc_fdinfo_read,
2156         .llseek         = no_llseek,
2157 };
2158
2159 static const struct file_operations proc_fd_operations = {
2160         .read           = generic_read_dir,
2161         .readdir        = proc_readfd,
2162         .llseek         = default_llseek,
2163 };
2164
2165 /*
2166  * /proc/pid/fd needs a special permission handler so that a process can still
2167  * access /proc/self/fd after it has executed a setuid().
2168  */
2169 static int proc_fd_permission(struct inode *inode, int mask)
2170 {
2171         int rv = generic_permission(inode, mask);
2172         if (rv == 0)
2173                 return 0;
2174         if (task_pid(current) == proc_pid(inode))
2175                 rv = 0;
2176         return rv;
2177 }
2178
2179 /*
2180  * proc directories can do almost nothing..
2181  */
2182 static const struct inode_operations proc_fd_inode_operations = {
2183         .lookup         = proc_lookupfd,
2184         .permission     = proc_fd_permission,
2185         .setattr        = proc_setattr,
2186 };
2187
2188 static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
2189         struct dentry *dentry, struct task_struct *task, const void *ptr)
2190 {
2191         unsigned fd = *(unsigned *)ptr;
2192         struct inode *inode;
2193         struct proc_inode *ei;
2194         struct dentry *error = ERR_PTR(-ENOENT);
2195
2196         inode = proc_pid_make_inode(dir->i_sb, task);
2197         if (!inode)
2198                 goto out;
2199         ei = PROC_I(inode);
2200         ei->fd = fd;
2201         inode->i_mode = S_IFREG | S_IRUSR;
2202         inode->i_fop = &proc_fdinfo_file_operations;
2203         d_set_d_op(dentry, &tid_fd_dentry_operations);
2204         d_add(dentry, inode);
2205         /* Close the race of the process dying before we return the dentry */
2206         if (tid_fd_revalidate(dentry, NULL))
2207                 error = NULL;
2208
2209  out:
2210         return error;
2211 }
2212
2213 static struct dentry *proc_lookupfdinfo(struct inode *dir,
2214                                         struct dentry *dentry,
2215                                         struct nameidata *nd)
2216 {
2217         return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
2218 }
2219
2220 static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
2221 {
2222         return proc_readfd_common(filp, dirent, filldir,
2223                                   proc_fdinfo_instantiate);
2224 }
2225
2226 static const struct file_operations proc_fdinfo_operations = {
2227         .read           = generic_read_dir,
2228         .readdir        = proc_readfdinfo,
2229         .llseek         = default_llseek,
2230 };
2231
2232 /*
2233  * proc directories can do almost nothing..
2234  */
2235 static const struct inode_operations proc_fdinfo_inode_operations = {
2236         .lookup         = proc_lookupfdinfo,
2237         .setattr        = proc_setattr,
2238 };
2239
2240
2241 static struct dentry *proc_pident_instantiate(struct inode *dir,
2242         struct dentry *dentry, struct task_struct *task, const void *ptr)
2243 {
2244         const struct pid_entry *p = ptr;
2245         struct inode *inode;
2246         struct proc_inode *ei;
2247         struct dentry *error = ERR_PTR(-ENOENT);
2248
2249         inode = proc_pid_make_inode(dir->i_sb, task);
2250         if (!inode)
2251                 goto out;
2252
2253         ei = PROC_I(inode);
2254         inode->i_mode = p->mode;
2255         if (S_ISDIR(inode->i_mode))
2256                 inode->i_nlink = 2;     /* Use getattr to fix if necessary */
2257         if (p->iop)
2258                 inode->i_op = p->iop;
2259         if (p->fop)
2260                 inode->i_fop = p->fop;
2261         ei->op = p->op;
2262         d_set_d_op(dentry, &pid_dentry_operations);
2263         d_add(dentry, inode);
2264         /* Close the race of the process dying before we return the dentry */
2265         if (pid_revalidate(dentry, NULL))
2266                 error = NULL;
2267 out:
2268         return error;
2269 }
2270
2271 static struct dentry *proc_pident_lookup(struct inode *dir, 
2272                                          struct dentry *dentry,
2273                                          const struct pid_entry *ents,
2274                                          unsigned int nents)
2275 {
2276         struct dentry *error;
2277         struct task_struct *task = get_proc_task(dir);
2278         const struct pid_entry *p, *last;
2279
2280         error = ERR_PTR(-ENOENT);
2281
2282         if (!task)
2283                 goto out_no_task;
2284
2285         /*
2286          * Yes, it does not scale. And it should not. Don't add
2287          * new entries into /proc/<tgid>/ without very good reasons.
2288          */
2289         last = &ents[nents - 1];
2290         for (p = ents; p <= last; p++) {
2291                 if (p->len != dentry->d_name.len)
2292                         continue;
2293                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2294                         break;
2295         }
2296         if (p > last)
2297                 goto out;
2298
2299         error = proc_pident_instantiate(dir, dentry, task, p);
2300 out:
2301         put_task_struct(task);
2302 out_no_task:
2303         return error;
2304 }
2305
2306 static int proc_pident_fill_cache(struct file *filp, void *dirent,
2307         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2308 {
2309         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2310                                 proc_pident_instantiate, task, p);
2311 }
2312
2313 static int proc_pident_readdir(struct file *filp,
2314                 void *dirent, filldir_t filldir,
2315                 const struct pid_entry *ents, unsigned int nents)
2316 {
2317         int i;
2318         struct dentry *dentry = filp->f_path.dentry;
2319         struct inode *inode = dentry->d_inode;
2320         struct task_struct *task = get_proc_task(inode);
2321         const struct pid_entry *p, *last;
2322         ino_t ino;
2323         int ret;
2324
2325         ret = -ENOENT;
2326         if (!task)
2327                 goto out_no_task;
2328
2329         ret = 0;
2330         i = filp->f_pos;
2331         switch (i) {
2332         case 0:
2333                 ino = inode->i_ino;
2334                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2335                         goto out;
2336                 i++;
2337                 filp->f_pos++;
2338                 /* fall through */
2339         case 1:
2340                 ino = parent_ino(dentry);
2341                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2342                         goto out;
2343                 i++;
2344                 filp->f_pos++;
2345                 /* fall through */
2346         default:
2347                 i -= 2;
2348                 if (i >= nents) {
2349                         ret = 1;
2350                         goto out;
2351                 }
2352                 p = ents + i;
2353                 last = &ents[nents - 1];
2354                 while (p <= last) {
2355                         if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2356                                 goto out;
2357                         filp->f_pos++;
2358                         p++;
2359                 }
2360         }
2361
2362         ret = 1;
2363 out:
2364         put_task_struct(task);
2365 out_no_task:
2366         return ret;
2367 }
2368
2369 #ifdef CONFIG_SECURITY
2370 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2371                                   size_t count, loff_t *ppos)
2372 {
2373         struct inode * inode = file->f_path.dentry->d_inode;
2374         char *p = NULL;
2375         ssize_t length;
2376         struct task_struct *task = get_proc_task(inode);
2377
2378         if (!task)
2379                 return -ESRCH;
2380
2381         length = security_getprocattr(task,
2382                                       (char*)file->f_path.dentry->d_name.name,
2383                                       &p);
2384         put_task_struct(task);
2385         if (length > 0)
2386                 length = simple_read_from_buffer(buf, count, ppos, p, length);
2387         kfree(p);
2388         return length;
2389 }
2390
2391 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2392                                    size_t count, loff_t *ppos)
2393 {
2394         struct inode * inode = file->f_path.dentry->d_inode;
2395         char *page;
2396         ssize_t length;
2397         struct task_struct *task = get_proc_task(inode);
2398
2399         length = -ESRCH;
2400         if (!task)
2401                 goto out_no_task;
2402         if (count > PAGE_SIZE)
2403                 count = PAGE_SIZE;
2404
2405         /* No partial writes. */
2406         length = -EINVAL;
2407         if (*ppos != 0)
2408                 goto out;
2409
2410         length = -ENOMEM;
2411         page = (char*)__get_free_page(GFP_TEMPORARY);
2412         if (!page)
2413                 goto out;
2414
2415         length = -EFAULT;
2416         if (copy_from_user(page, buf, count))
2417                 goto out_free;
2418
2419         /* Guard against adverse ptrace interaction */
2420         length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
2421         if (length < 0)
2422                 goto out_free;
2423
2424         length = security_setprocattr(task,
2425                                       (char*)file->f_path.dentry->d_name.name,
2426                                       (void*)page, count);
2427         mutex_unlock(&task->signal->cred_guard_mutex);
2428 out_free:
2429         free_page((unsigned long) page);
2430 out:
2431         put_task_struct(task);
2432 out_no_task:
2433         return length;
2434 }
2435
2436 static const struct file_operations proc_pid_attr_operations = {
2437         .read           = proc_pid_attr_read,
2438         .write          = proc_pid_attr_write,
2439         .llseek         = generic_file_llseek,
2440 };
2441
2442 static const struct pid_entry attr_dir_stuff[] = {
2443         REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2444         REG("prev",       S_IRUGO,         proc_pid_attr_operations),
2445         REG("exec",       S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2446         REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2447         REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2448         REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
2449 };
2450
2451 static int proc_attr_dir_readdir(struct file * filp,
2452                              void * dirent, filldir_t filldir)
2453 {
2454         return proc_pident_readdir(filp,dirent,filldir,
2455                                    attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2456 }
2457
2458 static const struct file_operations proc_attr_dir_operations = {
2459         .read           = generic_read_dir,
2460         .readdir        = proc_attr_dir_readdir,
2461         .llseek         = default_llseek,
2462 };
2463
2464 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2465                                 struct dentry *dentry, struct nameidata *nd)
2466 {
2467         return proc_pident_lookup(dir, dentry,
2468                                   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2469 }
2470
2471 static const struct inode_operations proc_attr_dir_inode_operations = {
2472         .lookup         = proc_attr_dir_lookup,
2473         .getattr        = pid_getattr,
2474         .setattr        = proc_setattr,
2475 };
2476
2477 #endif
2478
2479 #ifdef CONFIG_ELF_CORE
2480 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2481                                          size_t count, loff_t *ppos)
2482 {
2483         struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2484         struct mm_struct *mm;
2485         char buffer[PROC_NUMBUF];
2486         size_t len;
2487         int ret;
2488
2489         if (!task)
2490                 return -ESRCH;
2491
2492         ret = 0;
2493         mm = get_task_mm(task);
2494         if (mm) {
2495                 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2496                                ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2497                                 MMF_DUMP_FILTER_SHIFT));
2498                 mmput(mm);
2499                 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2500         }
2501
2502         put_task_struct(task);
2503
2504         return ret;
2505 }
2506
2507 static ssize_t proc_coredump_filter_write(struct file *file,
2508                                           const char __user *buf,
2509                                           size_t count,
2510                                           loff_t *ppos)
2511 {
2512         struct task_struct *task;
2513         struct mm_struct *mm;
2514         char buffer[PROC_NUMBUF], *end;
2515         unsigned int val;
2516         int ret;
2517         int i;
2518         unsigned long mask;
2519
2520         ret = -EFAULT;
2521         memset(buffer, 0, sizeof(buffer));
2522         if (count > sizeof(buffer) - 1)
2523                 count = sizeof(buffer) - 1;
2524         if (copy_from_user(buffer, buf, count))
2525                 goto out_no_task;
2526
2527         ret = -EINVAL;
2528         val = (unsigned int)simple_strtoul(buffer, &end, 0);
2529         if (*end == '\n')
2530                 end++;
2531         if (end - buffer == 0)
2532                 goto out_no_task;
2533
2534         ret = -ESRCH;
2535         task = get_proc_task(file->f_dentry->d_inode);
2536         if (!task)
2537                 goto out_no_task;
2538
2539         ret = end - buffer;
2540         mm = get_task_mm(task);
2541         if (!mm)
2542                 goto out_no_mm;
2543
2544         for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2545                 if (val & mask)
2546                         set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2547                 else
2548                         clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2549         }
2550
2551         mmput(mm);
2552  out_no_mm:
2553         put_task_struct(task);
2554  out_no_task:
2555         return ret;
2556 }
2557
2558 static const struct file_operations proc_coredump_filter_operations = {
2559         .read           = proc_coredump_filter_read,
2560         .write          = proc_coredump_filter_write,
2561         .llseek         = generic_file_llseek,
2562 };
2563 #endif
2564
2565 /*
2566  * /proc/self:
2567  */
2568 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2569                               int buflen)
2570 {
2571         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2572         pid_t tgid = task_tgid_nr_ns(current, ns);
2573         char tmp[PROC_NUMBUF];
2574         if (!tgid)
2575                 return -ENOENT;
2576         sprintf(tmp, "%d", tgid);
2577         return vfs_readlink(dentry,buffer,buflen,tmp);
2578 }
2579
2580 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2581 {
2582         struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2583         pid_t tgid = task_tgid_nr_ns(current, ns);
2584         char *name = ERR_PTR(-ENOENT);
2585         if (tgid) {
2586                 name = __getname();
2587                 if (!name)
2588                         name = ERR_PTR(-ENOMEM);
2589                 else
2590                         sprintf(name, "%d", tgid);
2591         }
2592         nd_set_link(nd, name);
2593         return NULL;
2594 }
2595
2596 static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
2597                                 void *cookie)
2598 {
2599         char *s = nd_get_link(nd);
2600         if (!IS_ERR(s))
2601                 __putname(s);
2602 }
2603
2604 static const struct inode_operations proc_self_inode_operations = {
2605         .readlink       = proc_self_readlink,
2606         .follow_link    = proc_self_follow_link,
2607         .put_link       = proc_self_put_link,
2608 };
2609
2610 /*
2611  * proc base
2612  *
2613  * These are the directory entries in the root directory of /proc
2614  * that properly belong to the /proc filesystem, as they describe
2615  * describe something that is process related.
2616  */
2617 static const struct pid_entry proc_base_stuff[] = {
2618         NOD("self", S_IFLNK|S_IRWXUGO,
2619                 &proc_self_inode_operations, NULL, {}),
2620 };
2621
2622 static struct dentry *proc_base_instantiate(struct inode *dir,
2623         struct dentry *dentry, struct task_struct *task, const void *ptr)
2624 {
2625         const struct pid_entry *p = ptr;
2626         struct inode *inode;
2627         struct proc_inode *ei;
2628         struct dentry *error;
2629
2630         /* Allocate the inode */
2631         error = ERR_PTR(-ENOMEM);
2632         inode = new_inode(dir->i_sb);
2633         if (!inode)
2634                 goto out;
2635
2636         /* Initialize the inode */
2637         ei = PROC_I(inode);
2638         inode->i_ino = get_next_ino();
2639         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2640
2641         /*
2642          * grab the reference to the task.
2643          */
2644         ei->pid = get_task_pid(task, PIDTYPE_PID);
2645         if (!ei->pid)
2646                 goto out_iput;
2647
2648         inode->i_mode = p->mode;
2649         if (S_ISDIR(inode->i_mode))
2650                 inode->i_nlink = 2;
2651         if (S_ISLNK(inode->i_mode))
2652                 inode->i_size = 64;
2653         if (p->iop)
2654                 inode->i_op = p->iop;
2655         if (p->fop)
2656                 inode->i_fop = p->fop;
2657         ei->op = p->op;
2658         d_add(dentry, inode);
2659         error = NULL;
2660 out:
2661         return error;
2662 out_iput:
2663         iput(inode);
2664         goto out;
2665 }
2666
2667 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2668 {
2669         struct dentry *error;
2670         struct task_struct *task = get_proc_task(dir);
2671         const struct pid_entry *p, *last;
2672
2673         error = ERR_PTR(-ENOENT);
2674
2675         if (!task)
2676                 goto out_no_task;
2677
2678         /* Lookup the directory entry */
2679         last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2680         for (p = proc_base_stuff; p <= last; p++) {
2681                 if (p->len != dentry->d_name.len)
2682                         continue;
2683                 if (!memcmp(dentry->d_name.name, p->name, p->len))
2684                         break;
2685         }
2686         if (p > last)
2687                 goto out;
2688
2689         error = proc_base_instantiate(dir, dentry, task, p);
2690
2691 out:
2692         put_task_struct(task);
2693 out_no_task:
2694         return error;
2695 }
2696
2697 static int proc_base_fill_cache(struct file *filp, void *dirent,
2698         filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2699 {
2700         return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2701                                 proc_base_instantiate, task, p);
2702 }
2703
2704 #ifdef CONFIG_TASK_IO_ACCOUNTING
2705 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2706 {
2707         struct task_io_accounting acct = task->ioac;
2708         unsigned long flags;
2709         int result;
2710
2711         result = mutex_lock_killable(&task->signal->cred_guard_mutex);
2712         if (result)
2713                 return result;
2714
2715         if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
2716                 result = -EACCES;
2717                 goto out_unlock;
2718         }
2719
2720         if (whole && lock_task_sighand(task, &flags)) {
2721                 struct task_struct *t = task;
2722
2723                 task_io_accounting_add(&acct, &task->signal->ioac);
2724                 while_each_thread(task, t)
2725                         task_io_accounting_add(&acct, &t->ioac);
2726
2727                 unlock_task_sighand(task, &flags);
2728         }
2729         result = sprintf(buffer,
2730                         "rchar: %llu\n"
2731                         "wchar: %llu\n"
2732                         "syscr: %llu\n"
2733                         "syscw: %llu\n"
2734                         "read_bytes: %llu\n"
2735                         "write_bytes: %llu\n"
2736                         "cancelled_write_bytes: %llu\n",
2737                         (unsigned long long)acct.rchar,
2738                         (unsigned long long)acct.wchar,
2739                         (unsigned long long)acct.syscr,
2740                         (unsigned long long)acct.syscw,
2741                         (unsigned long long)acct.read_bytes,
2742                         (unsigned long long)acct.write_bytes,
2743                         (unsigned long long)acct.cancelled_write_bytes);
2744 out_unlock:
2745         mutex_unlock(&task->signal->cred_guard_mutex);
2746         return result;
2747 }
2748
2749 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2750 {
2751         return do_io_accounting(task, buffer, 0);
2752 }
2753
2754 static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2755 {
2756         return do_io_accounting(task, buffer, 1);
2757 }
2758 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2759
2760 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
2761                                 struct pid *pid, struct task_struct *task)
2762 {
2763         int err = lock_trace(task);
2764         if (!err) {
2765                 seq_printf(m, "%08x\n", task->personality);
2766                 unlock_trace(task);
2767         }
2768         return err;
2769 }
2770
2771 /*
2772  * Thread groups
2773  */
2774 static const struct file_operations proc_task_operations;
2775 static const struct inode_operations proc_task_inode_operations;
2776
2777 static const struct pid_entry tgid_base_stuff[] = {
2778         DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
2779         DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
2780         DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
2781         DIR("ns",         S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
2782 #ifdef CONFIG_NET
2783         DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
2784 #endif
2785         REG("environ",    S_IRUSR, proc_environ_operations),
2786         INF("auxv",       S_IRUSR, proc_pid_auxv),
2787         ONE("status",     S_IRUGO, proc_pid_status),
2788         ONE("personality", S_IRUGO, proc_pid_personality),
2789         INF("limits",     S_IRUGO, proc_pid_limits),
2790 #ifdef CONFIG_SCHED_DEBUG
2791         REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
2792 #endif
2793 #ifdef CONFIG_SCHED_AUTOGROUP
2794         REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
2795 #endif
2796         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
2797 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2798         INF("syscall",    S_IRUGO, proc_pid_syscall),
2799 #endif
2800         INF("cmdline",    S_IRUGO, proc_pid_cmdline),
2801         ONE("stat",       S_IRUGO, proc_tgid_stat),
2802         ONE("statm",      S_IRUGO, proc_pid_statm),
2803         REG("maps",       S_IRUGO, proc_maps_operations),
2804 #ifdef CONFIG_NUMA
2805         REG("numa_maps",  S_IRUGO, proc_numa_maps_operations),
2806 #endif
2807         REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
2808         LNK("cwd",        proc_cwd_link),
2809         LNK("root",       proc_root_link),
2810         LNK("exe",        proc_exe_link),
2811         REG("mounts",     S_IRUGO, proc_mounts_operations),
2812         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
2813         REG("mountstats", S_IRUSR, proc_mountstats_operations),
2814 #ifdef CONFIG_PROC_PAGE_MONITOR
2815         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
2816         REG("smaps",      S_IRUGO, proc_smaps_operations),
2817         REG("pagemap",    S_IRUGO, proc_pagemap_operations),
2818 #endif
2819 #ifdef CONFIG_SECURITY
2820         DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
2821 #endif
2822 #ifdef CONFIG_KALLSYMS
2823         INF("wchan",      S_IRUGO, proc_pid_wchan),
2824 #endif
2825 #ifdef CONFIG_STACKTRACE
2826         ONE("stack",      S_IRUGO, proc_pid_stack),
2827 #endif
2828 #ifdef CONFIG_SCHEDSTATS
2829         INF("schedstat",  S_IRUGO, proc_pid_schedstat),
2830 #endif
2831 #ifdef CONFIG_LATENCYTOP
2832         REG("latency",  S_IRUGO, proc_lstats_operations),
2833 #endif
2834 #ifdef CONFIG_PROC_PID_CPUSET
2835         REG("cpuset",     S_IRUGO, proc_cpuset_operations),
2836 #endif
2837 #ifdef CONFIG_CGROUPS
2838         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
2839 #endif
2840         INF("oom_score",  S_IRUGO, proc_oom_score),
2841         REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
2842         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
2843 #ifdef CONFIG_AUDITSYSCALL
2844         REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
2845         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
2846 #endif
2847 #ifdef CONFIG_FAULT_INJECTION
2848         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
2849 #endif
2850 #ifdef CONFIG_ELF_CORE
2851         REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
2852 #endif
2853 #ifdef CONFIG_TASK_IO_ACCOUNTING
2854         INF("io",       S_IRUSR, proc_tgid_io_accounting),
2855 #endif
2856 #ifdef CONFIG_HARDWALL
2857         INF("hardwall",   S_IRUGO, proc_pid_hardwall),
2858 #endif
2859 };
2860
2861 static int proc_tgid_base_readdir(struct file * filp,
2862                              void * dirent, filldir_t filldir)
2863 {
2864         return proc_pident_readdir(filp,dirent,filldir,
2865                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2866 }
2867
2868 static const struct file_operations proc_tgid_base_operations = {
2869         .read           = generic_read_dir,
2870         .readdir        = proc_tgid_base_readdir,
2871         .llseek         = default_llseek,
2872 };
2873
2874 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2875         return proc_pident_lookup(dir, dentry,
2876                                   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2877 }
2878
2879 static const struct inode_operations proc_tgid_base_inode_operations = {
2880         .lookup         = proc_tgid_base_lookup,
2881         .getattr        = pid_getattr,
2882         .setattr        = proc_setattr,
2883 };
2884
2885 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2886 {
2887         struct dentry *dentry, *leader, *dir;
2888         char buf[PROC_NUMBUF];
2889         struct qstr name;
2890
2891         name.name = buf;
2892         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2893         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2894         if (dentry) {
2895                 shrink_dcache_parent(dentry);
2896                 d_drop(dentry);
2897                 dput(dentry);
2898         }
2899
2900         name.name = buf;
2901         name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2902         leader = d_hash_and_lookup(mnt->mnt_root, &name);
2903         if (!leader)
2904                 goto out;
2905
2906         name.name = "task";
2907         name.len = strlen(name.name);
2908         dir = d_hash_and_lookup(leader, &name);
2909         if (!dir)
2910                 goto out_put_leader;
2911
2912         name.name = buf;
2913         name.len = snprintf(buf, sizeof(buf), "%d", pid);
2914         dentry = d_hash_and_lookup(dir, &name);
2915         if (dentry) {
2916                 shrink_dcache_parent(dentry);
2917                 d_drop(dentry);
2918                 dput(dentry);
2919         }
2920
2921         dput(dir);
2922 out_put_leader:
2923         dput(leader);
2924 out:
2925         return;
2926 }
2927
2928 /**
2929  * proc_flush_task -  Remove dcache entries for @task from the /proc dcache.
2930  * @task: task that should be flushed.
2931  *
2932  * When flushing dentries from proc, one needs to flush them from global
2933  * proc (proc_mnt) and from all the namespaces' procs this task was seen
2934  * in. This call is supposed to do all of this job.
2935  *
2936  * Looks in the dcache for
2937  * /proc/@pid
2938  * /proc/@tgid/task/@pid
2939  * if either directory is present flushes it and all of it'ts children
2940  * from the dcache.
2941  *
2942  * It is safe and reasonable to cache /proc entries for a task until
2943  * that task exits.  After that they just clog up the dcache with
2944  * useless entries, possibly causing useful dcache entries to be
2945  * flushed instead.  This routine is proved to flush those useless
2946  * dcache entries at process exit time.
2947  *
2948  * NOTE: This routine is just an optimization so it does not guarantee
2949  *       that no dcache entries will exist at process exit time it
2950  *       just makes it very unlikely that any will persist.
2951  */
2952
2953 void proc_flush_task(struct task_struct *task)
2954 {
2955         int i;
2956         struct pid *pid, *tgid;
2957         struct upid *upid;
2958
2959         pid = task_pid(task);
2960         tgid = task_tgid(task);
2961
2962         for (i = 0; i <= pid->level; i++) {
2963                 upid = &pid->numbers[i];
2964                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2965                                         tgid->numbers[i].nr);
2966         }
2967
2968         upid = &pid->numbers[pid->level];
2969         if (upid->nr == 1)
2970                 pid_ns_release_proc(upid->ns);
2971 }
2972
2973 static struct dentry *proc_pid_instantiate(struct inode *dir,
2974                                            struct dentry * dentry,
2975                                            struct task_struct *task, const void *ptr)
2976 {
2977         struct dentry *error = ERR_PTR(-ENOENT);
2978         struct inode *inode;
2979
2980         inode = proc_pid_make_inode(dir->i_sb, task);
2981         if (!inode)
2982                 goto out;
2983
2984         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2985         inode->i_op = &proc_tgid_base_inode_operations;
2986         inode->i_fop = &proc_tgid_base_operations;
2987         inode->i_flags|=S_IMMUTABLE;
2988
2989         inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
2990                 ARRAY_SIZE(tgid_base_stuff));
2991
2992         d_set_d_op(dentry, &pid_dentry_operations);
2993
2994         d_add(dentry, inode);
2995         /* Close the race of the process dying before we return the dentry */
2996         if (pid_revalidate(dentry, NULL))
2997                 error = NULL;
2998 out:
2999         return error;
3000 }
3001
3002 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3003 {
3004         struct dentry *result;
3005         struct task_struct *task;
3006         unsigned tgid;
3007         struct pid_namespace *ns;
3008
3009         result = proc_base_lookup(dir, dentry);
3010         if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
3011                 goto out;
3012
3013         tgid = name_to_int(dentry);
3014         if (tgid == ~0U)
3015                 goto out;
3016
3017         ns = dentry->d_sb->s_fs_info;
3018         rcu_read_lock();
3019         task = find_task_by_pid_ns(tgid, ns);
3020         if (task)
3021                 get_task_struct(task);
3022         rcu_read_unlock();
3023         if (!task)
3024                 goto out;
3025
3026         result = proc_pid_instantiate(dir, dentry, task, NULL);
3027         put_task_struct(task);
3028 out:
3029         return result;
3030 }
3031
3032 /*
3033  * Find the first task with tgid >= tgid
3034  *
3035  */
3036 struct tgid_iter {
3037         unsigned int tgid;
3038         struct task_struct *task;
3039 };
3040 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
3041 {
3042         struct pid *pid;
3043
3044         if (iter.task)
3045                 put_task_struct(iter.task);
3046         rcu_read_lock();
3047 retry:
3048         iter.task = NULL;
3049         pid = find_ge_pid(iter.tgid, ns);
3050         if (pid) {
3051                 iter.tgid = pid_nr_ns(pid, ns);
3052                 iter.task = pid_task(pid, PIDTYPE_PID);
3053                 /* What we to know is if the pid we have find is the
3054                  * pid of a thread_group_leader.  Testing for task
3055                  * being a thread_group_leader is the obvious thing
3056                  * todo but there is a window when it fails, due to
3057                  * the pid transfer logic in de_thread.
3058                  *
3059                  * So we perform the straight forward test of seeing
3060                  * if the pid we have found is the pid of a thread
3061                  * group leader, and don't worry if the task we have
3062                  * found doesn't happen to be a thread group leader.
3063                  * As we don't care in the case of readdir.
3064                  */
3065                 if (!iter.task || !has_group_leader_pid(iter.task)) {
3066                         iter.tgid += 1;
3067                         goto retry;
3068                 }
3069                 get_task_struct(iter.task);
3070         }
3071         rcu_read_unlock();
3072         return iter;
3073 }
3074
3075 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
3076
3077 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3078         struct tgid_iter iter)
3079 {
3080         char name[PROC_NUMBUF];
3081         int len = snprintf(name, sizeof(name), "%d", iter.tgid);
3082         return proc_fill_cache(filp, dirent, filldir, name, len,
3083                                 proc_pid_instantiate, iter.task, NULL);
3084 }
3085
3086 /* for the /proc/ directory itself, after non-process stuff has been done */
3087 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
3088 {
3089         unsigned int nr;
3090         struct task_struct *reaper;
3091         struct tgid_iter iter;
3092         struct pid_namespace *ns;
3093
3094         if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
3095                 goto out_no_task;
3096         nr = filp->f_pos - FIRST_PROCESS_ENTRY;
3097
3098         reaper = get_proc_task(filp->f_path.dentry->d_inode);
3099         if (!reaper)
3100                 goto out_no_task;
3101
3102         for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
3103                 const struct pid_entry *p = &proc_base_stuff[nr];
3104                 if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
3105                         goto out;
3106         }
3107
3108         ns = filp->f_dentry->d_sb->s_fs_info;
3109         iter.task = NULL;
3110         iter.tgid = filp->f_pos - TGID_OFFSET;
3111         for (iter = next_tgid(ns, iter);
3112              iter.task;
3113              iter.tgid += 1, iter = next_tgid(ns, iter)) {
3114                 filp->f_pos = iter.tgid + TGID_OFFSET;
3115                 if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
3116                         put_task_struct(iter.task);
3117                         goto out;
3118                 }
3119         }
3120         filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
3121 out:
3122         put_task_struct(reaper);
3123 out_no_task:
3124         return 0;
3125 }
3126
3127 /*
3128  * Tasks
3129  */
3130 static const struct pid_entry tid_base_stuff[] = {
3131         DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
3132         DIR("fdinfo",    S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
3133         DIR("ns",        S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
3134         REG("environ",   S_IRUSR, proc_environ_operations),
3135         INF("auxv",      S_IRUSR, proc_pid_auxv),
3136         ONE("status",    S_IRUGO, proc_pid_status),
3137         ONE("personality", S_IRUGO, proc_pid_personality),
3138         INF("limits",    S_IRUGO, proc_pid_limits),
3139 #ifdef CONFIG_SCHED_DEBUG
3140         REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
3141 #endif
3142         REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
3143 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
3144         INF("syscall",   S_IRUGO, proc_pid_syscall),
3145 #endif
3146         INF("cmdline",   S_IRUGO, proc_pid_cmdline),
3147         ONE("stat",      S_IRUGO, proc_tid_stat),
3148         ONE("statm",     S_IRUGO, proc_pid_statm),
3149         REG("maps",      S_IRUGO, proc_maps_operations),
3150 #ifdef CONFIG_NUMA
3151         REG("numa_maps", S_IRUGO, proc_numa_maps_operations),
3152 #endif
3153         REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
3154         LNK("cwd",       proc_cwd_link),
3155         LNK("root",      proc_root_link),
3156         LNK("exe",       proc_exe_link),
3157         REG("mounts",    S_IRUGO, proc_mounts_operations),
3158         REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
3159 #ifdef CONFIG_PROC_PAGE_MONITOR
3160         REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
3161         REG("smaps",     S_IRUGO, proc_smaps_operations),
3162         REG("pagemap",    S_IRUGO, proc_pagemap_operations),
3163 #endif
3164 #ifdef CONFIG_SECURITY
3165         DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
3166 #endif
3167 #ifdef CONFIG_KALLSYMS
3168         INF("wchan",     S_IRUGO, proc_pid_wchan),
3169 #endif
3170 #ifdef CONFIG_STACKTRACE
3171         ONE("stack",      S_IRUGO, proc_pid_stack),
3172 #endif
3173 #ifdef CONFIG_SCHEDSTATS
3174         INF("schedstat", S_IRUGO, proc_pid_schedstat),
3175 #endif
3176 #ifdef CONFIG_LATENCYTOP
3177         REG("latency",  S_IRUGO, proc_lstats_operations),
3178 #endif
3179 #ifdef CONFIG_PROC_PID_CPUSET
3180         REG("cpuset",    S_IRUGO, proc_cpuset_operations),
3181 #endif
3182 #ifdef CONFIG_CGROUPS
3183         REG("cgroup",  S_IRUGO, proc_cgroup_operations),
3184 #endif
3185         INF("oom_score", S_IRUGO, proc_oom_score),
3186         REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adjust_operations),
3187         REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
3188 #ifdef CONFIG_AUDITSYSCALL
3189         REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
3190         REG("sessionid",  S_IRUGO, proc_sessionid_operations),
3191 #endif
3192 #ifdef CONFIG_FAULT_INJECTION
3193         REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
3194 #endif
3195 #ifdef CONFIG_TASK_IO_ACCOUNTING
3196         INF("io",       S_IRUSR, proc_tid_io_accounting),
3197 #endif
3198 #ifdef CONFIG_HARDWALL
3199         INF("hardwall",   S_IRUGO, proc_pid_hardwall),
3200 #endif
3201 };
3202
3203 static int proc_tid_base_readdir(struct file * filp,
3204                              void * dirent, filldir_t filldir)
3205 {
3206         return proc_pident_readdir(filp,dirent,filldir,
3207                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
3208 }
3209
3210 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
3211         return proc_pident_lookup(dir, dentry,
3212                                   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
3213 }
3214
3215 static const struct file_operations proc_tid_base_operations = {
3216         .read           = generic_read_dir,
3217         .readdir        = proc_tid_base_readdir,
3218         .llseek         = default_llseek,
3219 };
3220
3221 static const struct inode_operations proc_tid_base_inode_operations = {
3222         .lookup         = proc_tid_base_lookup,
3223         .getattr        = pid_getattr,
3224         .setattr        = proc_setattr,
3225 };
3226
3227 static struct dentry *proc_task_instantiate(struct inode *dir,
3228         struct dentry *dentry, struct task_struct *task, const void *ptr)
3229 {
3230         struct dentry *error = ERR_PTR(-ENOENT);
3231         struct inode *inode;
3232         inode = proc_pid_make_inode(dir->i_sb, task);
3233
3234         if (!inode)
3235                 goto out;
3236         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
3237         inode->i_op = &proc_tid_base_inode_operations;
3238         inode->i_fop = &proc_tid_base_operations;
3239         inode->i_flags|=S_IMMUTABLE;
3240
3241         inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
3242                 ARRAY_SIZE(tid_base_stuff));
3243
3244         d_set_d_op(dentry, &pid_dentry_operations);
3245
3246         d_add(dentry, inode);
3247         /* Close the race of the process dying before we return the dentry */
3248         if (pid_revalidate(dentry, NULL))
3249                 error = NULL;
3250 out:
3251         return error;
3252 }
3253
3254 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
3255 {
3256         struct dentry *result = ERR_PTR(-ENOENT);
3257         struct task_struct *task;
3258         struct task_struct *leader = get_proc_task(dir);
3259         unsigned tid;
3260         struct pid_namespace *ns;
3261
3262         if (!leader)
3263                 goto out_no_task;
3264
3265         tid = name_to_int(dentry);
3266         if (tid == ~0U)
3267                 goto out;
3268
3269         ns = dentry->d_sb->s_fs_info;
3270         rcu_read_lock();
3271         task = find_task_by_pid_ns(tid, ns);
3272         if (task)
3273                 get_task_struct(task);
3274         rcu_read_unlock();
3275         if (!task)
3276                 goto out;
3277         if (!same_thread_group(leader, task))
3278                 goto out_drop_task;
3279
3280         result = proc_task_instantiate(dir, dentry, task, NULL);
3281 out_drop_task:
3282         put_task_struct(task);
3283 out:
3284         put_task_struct(leader);
3285 out_no_task:
3286         return result;
3287 }
3288
3289 /*
3290  * Find the first tid of a thread group to return to user space.
3291  *
3292  * Usually this is just the thread group leader, but if the users
3293  * buffer was too small or there was a seek into the middle of the
3294  * directory we have more work todo.
3295  *
3296  * In the case of a short read we start with find_task_by_pid.
3297  *
3298  * In the case of a seek we start with the leader and walk nr
3299  * threads past it.
3300  */
3301 static struct task_struct *first_tid(struct task_struct *leader,
3302                 int tid, int nr, struct pid_namespace *ns)
3303 {
3304         struct task_struct *pos;
3305
3306         rcu_read_lock();
3307         /* Attempt to start with the pid of a thread */
3308         if (tid && (nr > 0)) {
3309                 pos = find_task_by_pid_ns(tid, ns);
3310                 if (pos && (pos->group_leader == leader))
3311                         goto found;
3312         }
3313
3314         /* If nr exceeds the number of threads there is nothing todo */
3315         pos = NULL;
3316         if (nr && nr >= get_nr_threads(leader))
3317                 goto out;
3318
3319         /* If we haven't found our starting place yet start
3320          * with the leader and walk nr threads forward.
3321          */
3322         for (pos = leader; nr > 0; --nr) {
3323                 pos = next_thread(pos);
3324                 if (pos == leader) {
3325                         pos = NULL;
3326                         goto out;
3327                 }
3328         }
3329 found:
3330         get_task_struct(pos);
3331 out:
3332         rcu_read_unlock();
3333         return pos;
3334 }
3335
3336 /*
3337  * Find the next thread in the thread list.
3338  * Return NULL if there is an error or no next thread.
3339  *
3340  * The reference to the input task_struct is released.
3341  */
3342 static struct task_struct *next_tid(struct task_struct *start)
3343 {
3344         struct task_struct *pos = NULL;
3345         rcu_read_lock();
3346         if (pid_alive(start)) {
3347                 pos = next_thread(start);
3348                 if (thread_group_leader(pos))
3349                         pos = NULL;
3350                 else
3351                         get_task_struct(pos);
3352         }
3353         rcu_read_unlock();
3354         put_task_struct(start);
3355         return pos;
3356 }
3357
3358 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3359         struct task_struct *task, int tid)
3360 {
3361         char name[PROC_NUMBUF];
3362         int len = snprintf(name, sizeof(name), "%d", tid);
3363         return proc_fill_cache(filp, dirent, filldir, name, len,
3364                                 proc_task_instantiate, task, NULL);
3365 }
3366
3367 /* for the /proc/TGID/task/ directories */
3368 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3369 {
3370         struct dentry *dentry = filp->f_path.dentry;
3371         struct inode *inode = dentry->d_inode;
3372         struct task_struct *leader = NULL;
3373         struct task_struct *task;
3374         int retval = -ENOENT;
3375         ino_t ino;
3376         int tid;
3377         struct pid_namespace *ns;
3378
3379         task = get_proc_task(inode);
3380         if (!task)
3381                 goto out_no_task;
3382         rcu_read_lock();
3383         if (pid_alive(task)) {
3384                 leader = task->group_leader;
3385                 get_task_struct(leader);
3386         }
3387         rcu_read_unlock();
3388         put_task_struct(task);
3389         if (!leader)
3390                 goto out_no_task;
3391         retval = 0;
3392
3393         switch ((unsigned long)filp->f_pos) {
3394         case 0:
3395                 ino = inode->i_ino;
3396                 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) < 0)
3397                         goto out;
3398                 filp->f_pos++;
3399                 /* fall through */
3400         case 1:
3401                 ino = parent_ino(dentry);
3402                 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) < 0)
3403                         goto out;
3404                 filp->f_pos++;
3405                 /* fall through */
3406         }
3407
3408         /* f_version caches the tgid value that the last readdir call couldn't
3409          * return. lseek aka telldir automagically resets f_version to 0.
3410          */
3411         ns = filp->f_dentry->d_sb->s_fs_info;
3412         tid = (int)filp->f_version;
3413         filp->f_version = 0;
3414         for (task = first_tid(leader, tid, filp->f_pos - 2, ns);
3415              task;
3416              task = next_tid(task), filp->f_pos++) {
3417                 tid = task_pid_nr_ns(task, ns);
3418                 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3419                         /* returning this tgid failed, save it as the first
3420                          * pid for the next readir call */
3421                         filp->f_version = (u64)tid;
3422                         put_task_struct(task);
3423                         break;
3424                 }
3425         }
3426 out:
3427         put_task_struct(leader);
3428 out_no_task:
3429         return retval;
3430 }
3431
3432 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3433 {
3434         struct inode *inode = dentry->d_inode;
3435         struct task_struct *p = get_proc_task(inode);
3436         generic_fillattr(inode, stat);
3437
3438         if (p) {
3439                 stat->nlink += get_nr_threads(p);
3440                 put_task_struct(p);
3441         }
3442
3443         return 0;
3444 }
3445
3446 static const struct inode_operations proc_task_inode_operations = {
3447         .lookup         = proc_task_lookup,
3448         .getattr        = proc_task_getattr,
3449         .setattr        = proc_setattr,
3450 };
3451
3452 static const struct file_operations proc_task_operations = {
3453         .read           = generic_read_dir,
3454         .readdir        = proc_task_readdir,
3455         .llseek         = default_llseek,
3456 };