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task IO accounting: move all IO statistics in struct task_io_accounting
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1 /*
2 * linux/fs/proc/base.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * proc base directory handling functions
7 *
8 * 1999, Al Viro. Rewritten. Now it covers the whole per-process part.
9 * Instead of using magical inumbers to determine the kind of object
10 * we allocate and fill in-core inodes upon lookup. They don't even
11 * go into icache. We cache the reference to task_struct upon lookup too.
12 * Eventually it should become a filesystem in its own. We don't use the
13 * rest of procfs anymore.
14 *
15 *
16 * Changelog:
17 * 17-Jan-2005
18 * Allan Bezerra
19 * Bruna Moreira <bruna.moreira@indt.org.br>
20 * Edjard Mota <edjard.mota@indt.org.br>
21 * Ilias Biris <ilias.biris@indt.org.br>
22 * Mauricio Lin <mauricio.lin@indt.org.br>
23 *
24 * Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
25 *
26 * A new process specific entry (smaps) included in /proc. It shows the
27 * size of rss for each memory area. The maps entry lacks information
28 * about physical memory size (rss) for each mapped file, i.e.,
29 * rss information for executables and library files.
30 * This additional information is useful for any tools that need to know
31 * about physical memory consumption for a process specific library.
32 *
33 * Changelog:
34 * 21-Feb-2005
35 * Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
36 * Pud inclusion in the page table walking.
37 *
38 * ChangeLog:
39 * 10-Mar-2005
40 * 10LE Instituto Nokia de Tecnologia - INdT:
41 * A better way to walks through the page table as suggested by Hugh Dickins.
42 *
43 * Simo Piiroinen <simo.piiroinen@nokia.com>:
44 * Smaps information related to shared, private, clean and dirty pages.
45 *
46 * Paul Mundt <paul.mundt@nokia.com>:
47 * Overall revision about smaps.
48 */
49
50 #include <asm/uaccess.h>
51
52 #include <linux/errno.h>
53 #include <linux/time.h>
54 #include <linux/proc_fs.h>
55 #include <linux/stat.h>
56 #include <linux/task_io_accounting_ops.h>
57 #include <linux/init.h>
58 #include <linux/capability.h>
59 #include <linux/file.h>
60 #include <linux/fdtable.h>
61 #include <linux/string.h>
62 #include <linux/seq_file.h>
63 #include <linux/namei.h>
64 #include <linux/mnt_namespace.h>
65 #include <linux/mm.h>
66 #include <linux/rcupdate.h>
67 #include <linux/kallsyms.h>
68 #include <linux/resource.h>
69 #include <linux/module.h>
70 #include <linux/mount.h>
71 #include <linux/security.h>
72 #include <linux/ptrace.h>
73 #include <linux/tracehook.h>
74 #include <linux/cgroup.h>
75 #include <linux/cpuset.h>
76 #include <linux/audit.h>
77 #include <linux/poll.h>
78 #include <linux/nsproxy.h>
79 #include <linux/oom.h>
80 #include <linux/elf.h>
81 #include <linux/pid_namespace.h>
82 #include "internal.h"
83
84 /* NOTE:
85 * Implementing inode permission operations in /proc is almost
86 * certainly an error. Permission checks need to happen during
87 * each system call not at open time. The reason is that most of
88 * what we wish to check for permissions in /proc varies at runtime.
89 *
90 * The classic example of a problem is opening file descriptors
91 * in /proc for a task before it execs a suid executable.
92 */
93
94 struct pid_entry {
95 char *name;
96 int len;
97 mode_t mode;
98 const struct inode_operations *iop;
99 const struct file_operations *fop;
100 union proc_op op;
101 };
102
103 #define NOD(NAME, MODE, IOP, FOP, OP) { \
104 .name = (NAME), \
105 .len = sizeof(NAME) - 1, \
106 .mode = MODE, \
107 .iop = IOP, \
108 .fop = FOP, \
109 .op = OP, \
110 }
111
112 #define DIR(NAME, MODE, OTYPE) \
113 NOD(NAME, (S_IFDIR|(MODE)), \
114 &proc_##OTYPE##_inode_operations, &proc_##OTYPE##_operations, \
115 {} )
116 #define LNK(NAME, OTYPE) \
117 NOD(NAME, (S_IFLNK|S_IRWXUGO), \
118 &proc_pid_link_inode_operations, NULL, \
119 { .proc_get_link = &proc_##OTYPE##_link } )
120 #define REG(NAME, MODE, OTYPE) \
121 NOD(NAME, (S_IFREG|(MODE)), NULL, \
122 &proc_##OTYPE##_operations, {})
123 #define INF(NAME, MODE, OTYPE) \
124 NOD(NAME, (S_IFREG|(MODE)), \
125 NULL, &proc_info_file_operations, \
126 { .proc_read = &proc_##OTYPE } )
127 #define ONE(NAME, MODE, OTYPE) \
128 NOD(NAME, (S_IFREG|(MODE)), \
129 NULL, &proc_single_file_operations, \
130 { .proc_show = &proc_##OTYPE } )
131
132 /*
133 * Count the number of hardlinks for the pid_entry table, excluding the .
134 * and .. links.
135 */
136 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
137 unsigned int n)
138 {
139 unsigned int i;
140 unsigned int count;
141
142 count = 0;
143 for (i = 0; i < n; ++i) {
144 if (S_ISDIR(entries[i].mode))
145 ++count;
146 }
147
148 return count;
149 }
150
151 int maps_protect;
152 EXPORT_SYMBOL(maps_protect);
153
154 static struct fs_struct *get_fs_struct(struct task_struct *task)
155 {
156 struct fs_struct *fs;
157 task_lock(task);
158 fs = task->fs;
159 if(fs)
160 atomic_inc(&fs->count);
161 task_unlock(task);
162 return fs;
163 }
164
165 static int get_nr_threads(struct task_struct *tsk)
166 {
167 /* Must be called with the rcu_read_lock held */
168 unsigned long flags;
169 int count = 0;
170
171 if (lock_task_sighand(tsk, &flags)) {
172 count = atomic_read(&tsk->signal->count);
173 unlock_task_sighand(tsk, &flags);
174 }
175 return count;
176 }
177
178 static int proc_cwd_link(struct inode *inode, struct path *path)
179 {
180 struct task_struct *task = get_proc_task(inode);
181 struct fs_struct *fs = NULL;
182 int result = -ENOENT;
183
184 if (task) {
185 fs = get_fs_struct(task);
186 put_task_struct(task);
187 }
188 if (fs) {
189 read_lock(&fs->lock);
190 *path = fs->pwd;
191 path_get(&fs->pwd);
192 read_unlock(&fs->lock);
193 result = 0;
194 put_fs_struct(fs);
195 }
196 return result;
197 }
198
199 static int proc_root_link(struct inode *inode, struct path *path)
200 {
201 struct task_struct *task = get_proc_task(inode);
202 struct fs_struct *fs = NULL;
203 int result = -ENOENT;
204
205 if (task) {
206 fs = get_fs_struct(task);
207 put_task_struct(task);
208 }
209 if (fs) {
210 read_lock(&fs->lock);
211 *path = fs->root;
212 path_get(&fs->root);
213 read_unlock(&fs->lock);
214 result = 0;
215 put_fs_struct(fs);
216 }
217 return result;
218 }
219
220 /*
221 * Return zero if current may access user memory in @task, -error if not.
222 */
223 static int check_mem_permission(struct task_struct *task)
224 {
225 /*
226 * A task can always look at itself, in case it chooses
227 * to use system calls instead of load instructions.
228 */
229 if (task == current)
230 return 0;
231
232 /*
233 * If current is actively ptrace'ing, and would also be
234 * permitted to freshly attach with ptrace now, permit it.
235 */
236 if (task_is_stopped_or_traced(task)) {
237 int match;
238 rcu_read_lock();
239 match = (tracehook_tracer_task(task) == current);
240 rcu_read_unlock();
241 if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
242 return 0;
243 }
244
245 /*
246 * Noone else is allowed.
247 */
248 return -EPERM;
249 }
250
251 struct mm_struct *mm_for_maps(struct task_struct *task)
252 {
253 struct mm_struct *mm = get_task_mm(task);
254 if (!mm)
255 return NULL;
256 down_read(&mm->mmap_sem);
257 task_lock(task);
258 if (task->mm != mm)
259 goto out;
260 if (task->mm != current->mm &&
261 __ptrace_may_access(task, PTRACE_MODE_READ) < 0)
262 goto out;
263 task_unlock(task);
264 return mm;
265 out:
266 task_unlock(task);
267 up_read(&mm->mmap_sem);
268 mmput(mm);
269 return NULL;
270 }
271
272 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
273 {
274 int res = 0;
275 unsigned int len;
276 struct mm_struct *mm = get_task_mm(task);
277 if (!mm)
278 goto out;
279 if (!mm->arg_end)
280 goto out_mm; /* Shh! No looking before we're done */
281
282 len = mm->arg_end - mm->arg_start;
283
284 if (len > PAGE_SIZE)
285 len = PAGE_SIZE;
286
287 res = access_process_vm(task, mm->arg_start, buffer, len, 0);
288
289 // If the nul at the end of args has been overwritten, then
290 // assume application is using setproctitle(3).
291 if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
292 len = strnlen(buffer, res);
293 if (len < res) {
294 res = len;
295 } else {
296 len = mm->env_end - mm->env_start;
297 if (len > PAGE_SIZE - res)
298 len = PAGE_SIZE - res;
299 res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
300 res = strnlen(buffer, res);
301 }
302 }
303 out_mm:
304 mmput(mm);
305 out:
306 return res;
307 }
308
309 static int proc_pid_auxv(struct task_struct *task, char *buffer)
310 {
311 int res = 0;
312 struct mm_struct *mm = get_task_mm(task);
313 if (mm) {
314 unsigned int nwords = 0;
315 do
316 nwords += 2;
317 while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
318 res = nwords * sizeof(mm->saved_auxv[0]);
319 if (res > PAGE_SIZE)
320 res = PAGE_SIZE;
321 memcpy(buffer, mm->saved_auxv, res);
322 mmput(mm);
323 }
324 return res;
325 }
326
327
328 #ifdef CONFIG_KALLSYMS
329 /*
330 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
331 * Returns the resolved symbol. If that fails, simply return the address.
332 */
333 static int proc_pid_wchan(struct task_struct *task, char *buffer)
334 {
335 unsigned long wchan;
336 char symname[KSYM_NAME_LEN];
337
338 wchan = get_wchan(task);
339
340 if (lookup_symbol_name(wchan, symname) < 0)
341 return sprintf(buffer, "%lu", wchan);
342 else
343 return sprintf(buffer, "%s", symname);
344 }
345 #endif /* CONFIG_KALLSYMS */
346
347 #ifdef CONFIG_SCHEDSTATS
348 /*
349 * Provides /proc/PID/schedstat
350 */
351 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
352 {
353 return sprintf(buffer, "%llu %llu %lu\n",
354 task->sched_info.cpu_time,
355 task->sched_info.run_delay,
356 task->sched_info.pcount);
357 }
358 #endif
359
360 #ifdef CONFIG_LATENCYTOP
361 static int lstats_show_proc(struct seq_file *m, void *v)
362 {
363 int i;
364 struct inode *inode = m->private;
365 struct task_struct *task = get_proc_task(inode);
366
367 if (!task)
368 return -ESRCH;
369 seq_puts(m, "Latency Top version : v0.1\n");
370 for (i = 0; i < 32; i++) {
371 if (task->latency_record[i].backtrace[0]) {
372 int q;
373 seq_printf(m, "%i %li %li ",
374 task->latency_record[i].count,
375 task->latency_record[i].time,
376 task->latency_record[i].max);
377 for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
378 char sym[KSYM_NAME_LEN];
379 char *c;
380 if (!task->latency_record[i].backtrace[q])
381 break;
382 if (task->latency_record[i].backtrace[q] == ULONG_MAX)
383 break;
384 sprint_symbol(sym, task->latency_record[i].backtrace[q]);
385 c = strchr(sym, '+');
386 if (c)
387 *c = 0;
388 seq_printf(m, "%s ", sym);
389 }
390 seq_printf(m, "\n");
391 }
392
393 }
394 put_task_struct(task);
395 return 0;
396 }
397
398 static int lstats_open(struct inode *inode, struct file *file)
399 {
400 return single_open(file, lstats_show_proc, inode);
401 }
402
403 static ssize_t lstats_write(struct file *file, const char __user *buf,
404 size_t count, loff_t *offs)
405 {
406 struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
407
408 if (!task)
409 return -ESRCH;
410 clear_all_latency_tracing(task);
411 put_task_struct(task);
412
413 return count;
414 }
415
416 static const struct file_operations proc_lstats_operations = {
417 .open = lstats_open,
418 .read = seq_read,
419 .write = lstats_write,
420 .llseek = seq_lseek,
421 .release = single_release,
422 };
423
424 #endif
425
426 /* The badness from the OOM killer */
427 unsigned long badness(struct task_struct *p, unsigned long uptime);
428 static int proc_oom_score(struct task_struct *task, char *buffer)
429 {
430 unsigned long points;
431 struct timespec uptime;
432
433 do_posix_clock_monotonic_gettime(&uptime);
434 read_lock(&tasklist_lock);
435 points = badness(task, uptime.tv_sec);
436 read_unlock(&tasklist_lock);
437 return sprintf(buffer, "%lu\n", points);
438 }
439
440 struct limit_names {
441 char *name;
442 char *unit;
443 };
444
445 static const struct limit_names lnames[RLIM_NLIMITS] = {
446 [RLIMIT_CPU] = {"Max cpu time", "ms"},
447 [RLIMIT_FSIZE] = {"Max file size", "bytes"},
448 [RLIMIT_DATA] = {"Max data size", "bytes"},
449 [RLIMIT_STACK] = {"Max stack size", "bytes"},
450 [RLIMIT_CORE] = {"Max core file size", "bytes"},
451 [RLIMIT_RSS] = {"Max resident set", "bytes"},
452 [RLIMIT_NPROC] = {"Max processes", "processes"},
453 [RLIMIT_NOFILE] = {"Max open files", "files"},
454 [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
455 [RLIMIT_AS] = {"Max address space", "bytes"},
456 [RLIMIT_LOCKS] = {"Max file locks", "locks"},
457 [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
458 [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
459 [RLIMIT_NICE] = {"Max nice priority", NULL},
460 [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
461 [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
462 };
463
464 /* Display limits for a process */
465 static int proc_pid_limits(struct task_struct *task, char *buffer)
466 {
467 unsigned int i;
468 int count = 0;
469 unsigned long flags;
470 char *bufptr = buffer;
471
472 struct rlimit rlim[RLIM_NLIMITS];
473
474 rcu_read_lock();
475 if (!lock_task_sighand(task,&flags)) {
476 rcu_read_unlock();
477 return 0;
478 }
479 memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
480 unlock_task_sighand(task, &flags);
481 rcu_read_unlock();
482
483 /*
484 * print the file header
485 */
486 count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
487 "Limit", "Soft Limit", "Hard Limit", "Units");
488
489 for (i = 0; i < RLIM_NLIMITS; i++) {
490 if (rlim[i].rlim_cur == RLIM_INFINITY)
491 count += sprintf(&bufptr[count], "%-25s %-20s ",
492 lnames[i].name, "unlimited");
493 else
494 count += sprintf(&bufptr[count], "%-25s %-20lu ",
495 lnames[i].name, rlim[i].rlim_cur);
496
497 if (rlim[i].rlim_max == RLIM_INFINITY)
498 count += sprintf(&bufptr[count], "%-20s ", "unlimited");
499 else
500 count += sprintf(&bufptr[count], "%-20lu ",
501 rlim[i].rlim_max);
502
503 if (lnames[i].unit)
504 count += sprintf(&bufptr[count], "%-10s\n",
505 lnames[i].unit);
506 else
507 count += sprintf(&bufptr[count], "\n");
508 }
509
510 return count;
511 }
512
513 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
514 static int proc_pid_syscall(struct task_struct *task, char *buffer)
515 {
516 long nr;
517 unsigned long args[6], sp, pc;
518
519 if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
520 return sprintf(buffer, "running\n");
521
522 if (nr < 0)
523 return sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
524
525 return sprintf(buffer,
526 "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
527 nr,
528 args[0], args[1], args[2], args[3], args[4], args[5],
529 sp, pc);
530 }
531 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
532
533 /************************************************************************/
534 /* Here the fs part begins */
535 /************************************************************************/
536
537 /* permission checks */
538 static int proc_fd_access_allowed(struct inode *inode)
539 {
540 struct task_struct *task;
541 int allowed = 0;
542 /* Allow access to a task's file descriptors if it is us or we
543 * may use ptrace attach to the process and find out that
544 * information.
545 */
546 task = get_proc_task(inode);
547 if (task) {
548 allowed = ptrace_may_access(task, PTRACE_MODE_READ);
549 put_task_struct(task);
550 }
551 return allowed;
552 }
553
554 static int proc_setattr(struct dentry *dentry, struct iattr *attr)
555 {
556 int error;
557 struct inode *inode = dentry->d_inode;
558
559 if (attr->ia_valid & ATTR_MODE)
560 return -EPERM;
561
562 error = inode_change_ok(inode, attr);
563 if (!error)
564 error = inode_setattr(inode, attr);
565 return error;
566 }
567
568 static const struct inode_operations proc_def_inode_operations = {
569 .setattr = proc_setattr,
570 };
571
572 static int mounts_open_common(struct inode *inode, struct file *file,
573 const struct seq_operations *op)
574 {
575 struct task_struct *task = get_proc_task(inode);
576 struct nsproxy *nsp;
577 struct mnt_namespace *ns = NULL;
578 struct fs_struct *fs = NULL;
579 struct path root;
580 struct proc_mounts *p;
581 int ret = -EINVAL;
582
583 if (task) {
584 rcu_read_lock();
585 nsp = task_nsproxy(task);
586 if (nsp) {
587 ns = nsp->mnt_ns;
588 if (ns)
589 get_mnt_ns(ns);
590 }
591 rcu_read_unlock();
592 if (ns)
593 fs = get_fs_struct(task);
594 put_task_struct(task);
595 }
596
597 if (!ns)
598 goto err;
599 if (!fs)
600 goto err_put_ns;
601
602 read_lock(&fs->lock);
603 root = fs->root;
604 path_get(&root);
605 read_unlock(&fs->lock);
606 put_fs_struct(fs);
607
608 ret = -ENOMEM;
609 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
610 if (!p)
611 goto err_put_path;
612
613 file->private_data = &p->m;
614 ret = seq_open(file, op);
615 if (ret)
616 goto err_free;
617
618 p->m.private = p;
619 p->ns = ns;
620 p->root = root;
621 p->event = ns->event;
622
623 return 0;
624
625 err_free:
626 kfree(p);
627 err_put_path:
628 path_put(&root);
629 err_put_ns:
630 put_mnt_ns(ns);
631 err:
632 return ret;
633 }
634
635 static int mounts_release(struct inode *inode, struct file *file)
636 {
637 struct proc_mounts *p = file->private_data;
638 path_put(&p->root);
639 put_mnt_ns(p->ns);
640 return seq_release(inode, file);
641 }
642
643 static unsigned mounts_poll(struct file *file, poll_table *wait)
644 {
645 struct proc_mounts *p = file->private_data;
646 struct mnt_namespace *ns = p->ns;
647 unsigned res = 0;
648
649 poll_wait(file, &ns->poll, wait);
650
651 spin_lock(&vfsmount_lock);
652 if (p->event != ns->event) {
653 p->event = ns->event;
654 res = POLLERR;
655 }
656 spin_unlock(&vfsmount_lock);
657
658 return res;
659 }
660
661 static int mounts_open(struct inode *inode, struct file *file)
662 {
663 return mounts_open_common(inode, file, &mounts_op);
664 }
665
666 static const struct file_operations proc_mounts_operations = {
667 .open = mounts_open,
668 .read = seq_read,
669 .llseek = seq_lseek,
670 .release = mounts_release,
671 .poll = mounts_poll,
672 };
673
674 static int mountinfo_open(struct inode *inode, struct file *file)
675 {
676 return mounts_open_common(inode, file, &mountinfo_op);
677 }
678
679 static const struct file_operations proc_mountinfo_operations = {
680 .open = mountinfo_open,
681 .read = seq_read,
682 .llseek = seq_lseek,
683 .release = mounts_release,
684 .poll = mounts_poll,
685 };
686
687 static int mountstats_open(struct inode *inode, struct file *file)
688 {
689 return mounts_open_common(inode, file, &mountstats_op);
690 }
691
692 static const struct file_operations proc_mountstats_operations = {
693 .open = mountstats_open,
694 .read = seq_read,
695 .llseek = seq_lseek,
696 .release = mounts_release,
697 };
698
699 #define PROC_BLOCK_SIZE (3*1024) /* 4K page size but our output routines use some slack for overruns */
700
701 static ssize_t proc_info_read(struct file * file, char __user * buf,
702 size_t count, loff_t *ppos)
703 {
704 struct inode * inode = file->f_path.dentry->d_inode;
705 unsigned long page;
706 ssize_t length;
707 struct task_struct *task = get_proc_task(inode);
708
709 length = -ESRCH;
710 if (!task)
711 goto out_no_task;
712
713 if (count > PROC_BLOCK_SIZE)
714 count = PROC_BLOCK_SIZE;
715
716 length = -ENOMEM;
717 if (!(page = __get_free_page(GFP_TEMPORARY)))
718 goto out;
719
720 length = PROC_I(inode)->op.proc_read(task, (char*)page);
721
722 if (length >= 0)
723 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
724 free_page(page);
725 out:
726 put_task_struct(task);
727 out_no_task:
728 return length;
729 }
730
731 static const struct file_operations proc_info_file_operations = {
732 .read = proc_info_read,
733 };
734
735 static int proc_single_show(struct seq_file *m, void *v)
736 {
737 struct inode *inode = m->private;
738 struct pid_namespace *ns;
739 struct pid *pid;
740 struct task_struct *task;
741 int ret;
742
743 ns = inode->i_sb->s_fs_info;
744 pid = proc_pid(inode);
745 task = get_pid_task(pid, PIDTYPE_PID);
746 if (!task)
747 return -ESRCH;
748
749 ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
750
751 put_task_struct(task);
752 return ret;
753 }
754
755 static int proc_single_open(struct inode *inode, struct file *filp)
756 {
757 int ret;
758 ret = single_open(filp, proc_single_show, NULL);
759 if (!ret) {
760 struct seq_file *m = filp->private_data;
761
762 m->private = inode;
763 }
764 return ret;
765 }
766
767 static const struct file_operations proc_single_file_operations = {
768 .open = proc_single_open,
769 .read = seq_read,
770 .llseek = seq_lseek,
771 .release = single_release,
772 };
773
774 static int mem_open(struct inode* inode, struct file* file)
775 {
776 file->private_data = (void*)((long)current->self_exec_id);
777 return 0;
778 }
779
780 static ssize_t mem_read(struct file * file, char __user * buf,
781 size_t count, loff_t *ppos)
782 {
783 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
784 char *page;
785 unsigned long src = *ppos;
786 int ret = -ESRCH;
787 struct mm_struct *mm;
788
789 if (!task)
790 goto out_no_task;
791
792 if (check_mem_permission(task))
793 goto out;
794
795 ret = -ENOMEM;
796 page = (char *)__get_free_page(GFP_TEMPORARY);
797 if (!page)
798 goto out;
799
800 ret = 0;
801
802 mm = get_task_mm(task);
803 if (!mm)
804 goto out_free;
805
806 ret = -EIO;
807
808 if (file->private_data != (void*)((long)current->self_exec_id))
809 goto out_put;
810
811 ret = 0;
812
813 while (count > 0) {
814 int this_len, retval;
815
816 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
817 retval = access_process_vm(task, src, page, this_len, 0);
818 if (!retval || check_mem_permission(task)) {
819 if (!ret)
820 ret = -EIO;
821 break;
822 }
823
824 if (copy_to_user(buf, page, retval)) {
825 ret = -EFAULT;
826 break;
827 }
828
829 ret += retval;
830 src += retval;
831 buf += retval;
832 count -= retval;
833 }
834 *ppos = src;
835
836 out_put:
837 mmput(mm);
838 out_free:
839 free_page((unsigned long) page);
840 out:
841 put_task_struct(task);
842 out_no_task:
843 return ret;
844 }
845
846 #define mem_write NULL
847
848 #ifndef mem_write
849 /* This is a security hazard */
850 static ssize_t mem_write(struct file * file, const char __user *buf,
851 size_t count, loff_t *ppos)
852 {
853 int copied;
854 char *page;
855 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
856 unsigned long dst = *ppos;
857
858 copied = -ESRCH;
859 if (!task)
860 goto out_no_task;
861
862 if (check_mem_permission(task))
863 goto out;
864
865 copied = -ENOMEM;
866 page = (char *)__get_free_page(GFP_TEMPORARY);
867 if (!page)
868 goto out;
869
870 copied = 0;
871 while (count > 0) {
872 int this_len, retval;
873
874 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
875 if (copy_from_user(page, buf, this_len)) {
876 copied = -EFAULT;
877 break;
878 }
879 retval = access_process_vm(task, dst, page, this_len, 1);
880 if (!retval) {
881 if (!copied)
882 copied = -EIO;
883 break;
884 }
885 copied += retval;
886 buf += retval;
887 dst += retval;
888 count -= retval;
889 }
890 *ppos = dst;
891 free_page((unsigned long) page);
892 out:
893 put_task_struct(task);
894 out_no_task:
895 return copied;
896 }
897 #endif
898
899 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
900 {
901 switch (orig) {
902 case 0:
903 file->f_pos = offset;
904 break;
905 case 1:
906 file->f_pos += offset;
907 break;
908 default:
909 return -EINVAL;
910 }
911 force_successful_syscall_return();
912 return file->f_pos;
913 }
914
915 static const struct file_operations proc_mem_operations = {
916 .llseek = mem_lseek,
917 .read = mem_read,
918 .write = mem_write,
919 .open = mem_open,
920 };
921
922 static ssize_t environ_read(struct file *file, char __user *buf,
923 size_t count, loff_t *ppos)
924 {
925 struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
926 char *page;
927 unsigned long src = *ppos;
928 int ret = -ESRCH;
929 struct mm_struct *mm;
930
931 if (!task)
932 goto out_no_task;
933
934 if (!ptrace_may_access(task, PTRACE_MODE_READ))
935 goto out;
936
937 ret = -ENOMEM;
938 page = (char *)__get_free_page(GFP_TEMPORARY);
939 if (!page)
940 goto out;
941
942 ret = 0;
943
944 mm = get_task_mm(task);
945 if (!mm)
946 goto out_free;
947
948 while (count > 0) {
949 int this_len, retval, max_len;
950
951 this_len = mm->env_end - (mm->env_start + src);
952
953 if (this_len <= 0)
954 break;
955
956 max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
957 this_len = (this_len > max_len) ? max_len : this_len;
958
959 retval = access_process_vm(task, (mm->env_start + src),
960 page, this_len, 0);
961
962 if (retval <= 0) {
963 ret = retval;
964 break;
965 }
966
967 if (copy_to_user(buf, page, retval)) {
968 ret = -EFAULT;
969 break;
970 }
971
972 ret += retval;
973 src += retval;
974 buf += retval;
975 count -= retval;
976 }
977 *ppos = src;
978
979 mmput(mm);
980 out_free:
981 free_page((unsigned long) page);
982 out:
983 put_task_struct(task);
984 out_no_task:
985 return ret;
986 }
987
988 static const struct file_operations proc_environ_operations = {
989 .read = environ_read,
990 };
991
992 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
993 size_t count, loff_t *ppos)
994 {
995 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
996 char buffer[PROC_NUMBUF];
997 size_t len;
998 int oom_adjust;
999
1000 if (!task)
1001 return -ESRCH;
1002 oom_adjust = task->oomkilladj;
1003 put_task_struct(task);
1004
1005 len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
1006
1007 return simple_read_from_buffer(buf, count, ppos, buffer, len);
1008 }
1009
1010 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
1011 size_t count, loff_t *ppos)
1012 {
1013 struct task_struct *task;
1014 char buffer[PROC_NUMBUF], *end;
1015 int oom_adjust;
1016
1017 memset(buffer, 0, sizeof(buffer));
1018 if (count > sizeof(buffer) - 1)
1019 count = sizeof(buffer) - 1;
1020 if (copy_from_user(buffer, buf, count))
1021 return -EFAULT;
1022 oom_adjust = simple_strtol(buffer, &end, 0);
1023 if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
1024 oom_adjust != OOM_DISABLE)
1025 return -EINVAL;
1026 if (*end == '\n')
1027 end++;
1028 task = get_proc_task(file->f_path.dentry->d_inode);
1029 if (!task)
1030 return -ESRCH;
1031 if (oom_adjust < task->oomkilladj && !capable(CAP_SYS_RESOURCE)) {
1032 put_task_struct(task);
1033 return -EACCES;
1034 }
1035 task->oomkilladj = oom_adjust;
1036 put_task_struct(task);
1037 if (end - buffer == 0)
1038 return -EIO;
1039 return end - buffer;
1040 }
1041
1042 static const struct file_operations proc_oom_adjust_operations = {
1043 .read = oom_adjust_read,
1044 .write = oom_adjust_write,
1045 };
1046
1047 #ifdef CONFIG_AUDITSYSCALL
1048 #define TMPBUFLEN 21
1049 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1050 size_t count, loff_t *ppos)
1051 {
1052 struct inode * inode = file->f_path.dentry->d_inode;
1053 struct task_struct *task = get_proc_task(inode);
1054 ssize_t length;
1055 char tmpbuf[TMPBUFLEN];
1056
1057 if (!task)
1058 return -ESRCH;
1059 length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1060 audit_get_loginuid(task));
1061 put_task_struct(task);
1062 return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1063 }
1064
1065 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1066 size_t count, loff_t *ppos)
1067 {
1068 struct inode * inode = file->f_path.dentry->d_inode;
1069 char *page, *tmp;
1070 ssize_t length;
1071 uid_t loginuid;
1072
1073 if (!capable(CAP_AUDIT_CONTROL))
1074 return -EPERM;
1075
1076 if (current != pid_task(proc_pid(inode), PIDTYPE_PID))
1077 return -EPERM;
1078
1079 if (count >= PAGE_SIZE)
1080 count = PAGE_SIZE - 1;
1081
1082 if (*ppos != 0) {
1083 /* No partial writes. */
1084 return -EINVAL;
1085 }
1086 page = (char*)__get_free_page(GFP_TEMPORARY);
1087 if (!page)
1088 return -ENOMEM;
1089 length = -EFAULT;
1090 if (copy_from_user(page, buf, count))
1091 goto out_free_page;
1092
1093 page[count] = '\0';
1094 loginuid = simple_strtoul(page, &tmp, 10);
1095 if (tmp == page) {
1096 length = -EINVAL;
1097 goto out_free_page;
1098
1099 }
1100 length = audit_set_loginuid(current, loginuid);
1101 if (likely(length == 0))
1102 length = count;
1103
1104 out_free_page:
1105 free_page((unsigned long) page);
1106 return length;
1107 }
1108
1109 static const struct file_operations proc_loginuid_operations = {
1110 .read = proc_loginuid_read,
1111 .write = proc_loginuid_write,
1112 };
1113
1114 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1115 size_t count, loff_t *ppos)
1116 {
1117 struct inode * inode = file->f_path.dentry->d_inode;
1118 struct task_struct *task = get_proc_task(inode);
1119 ssize_t length;
1120 char tmpbuf[TMPBUFLEN];
1121
1122 if (!task)
1123 return -ESRCH;
1124 length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1125 audit_get_sessionid(task));
1126 put_task_struct(task);
1127 return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1128 }
1129
1130 static const struct file_operations proc_sessionid_operations = {
1131 .read = proc_sessionid_read,
1132 };
1133 #endif
1134
1135 #ifdef CONFIG_FAULT_INJECTION
1136 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1137 size_t count, loff_t *ppos)
1138 {
1139 struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1140 char buffer[PROC_NUMBUF];
1141 size_t len;
1142 int make_it_fail;
1143
1144 if (!task)
1145 return -ESRCH;
1146 make_it_fail = task->make_it_fail;
1147 put_task_struct(task);
1148
1149 len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1150
1151 return simple_read_from_buffer(buf, count, ppos, buffer, len);
1152 }
1153
1154 static ssize_t proc_fault_inject_write(struct file * file,
1155 const char __user * buf, size_t count, loff_t *ppos)
1156 {
1157 struct task_struct *task;
1158 char buffer[PROC_NUMBUF], *end;
1159 int make_it_fail;
1160
1161 if (!capable(CAP_SYS_RESOURCE))
1162 return -EPERM;
1163 memset(buffer, 0, sizeof(buffer));
1164 if (count > sizeof(buffer) - 1)
1165 count = sizeof(buffer) - 1;
1166 if (copy_from_user(buffer, buf, count))
1167 return -EFAULT;
1168 make_it_fail = simple_strtol(buffer, &end, 0);
1169 if (*end == '\n')
1170 end++;
1171 task = get_proc_task(file->f_dentry->d_inode);
1172 if (!task)
1173 return -ESRCH;
1174 task->make_it_fail = make_it_fail;
1175 put_task_struct(task);
1176 if (end - buffer == 0)
1177 return -EIO;
1178 return end - buffer;
1179 }
1180
1181 static const struct file_operations proc_fault_inject_operations = {
1182 .read = proc_fault_inject_read,
1183 .write = proc_fault_inject_write,
1184 };
1185 #endif
1186
1187
1188 #ifdef CONFIG_SCHED_DEBUG
1189 /*
1190 * Print out various scheduling related per-task fields:
1191 */
1192 static int sched_show(struct seq_file *m, void *v)
1193 {
1194 struct inode *inode = m->private;
1195 struct task_struct *p;
1196
1197 WARN_ON(!inode);
1198
1199 p = get_proc_task(inode);
1200 if (!p)
1201 return -ESRCH;
1202 proc_sched_show_task(p, m);
1203
1204 put_task_struct(p);
1205
1206 return 0;
1207 }
1208
1209 static ssize_t
1210 sched_write(struct file *file, const char __user *buf,
1211 size_t count, loff_t *offset)
1212 {
1213 struct inode *inode = file->f_path.dentry->d_inode;
1214 struct task_struct *p;
1215
1216 WARN_ON(!inode);
1217
1218 p = get_proc_task(inode);
1219 if (!p)
1220 return -ESRCH;
1221 proc_sched_set_task(p);
1222
1223 put_task_struct(p);
1224
1225 return count;
1226 }
1227
1228 static int sched_open(struct inode *inode, struct file *filp)
1229 {
1230 int ret;
1231
1232 ret = single_open(filp, sched_show, NULL);
1233 if (!ret) {
1234 struct seq_file *m = filp->private_data;
1235
1236 m->private = inode;
1237 }
1238 return ret;
1239 }
1240
1241 static const struct file_operations proc_pid_sched_operations = {
1242 .open = sched_open,
1243 .read = seq_read,
1244 .write = sched_write,
1245 .llseek = seq_lseek,
1246 .release = single_release,
1247 };
1248
1249 #endif
1250
1251 /*
1252 * We added or removed a vma mapping the executable. The vmas are only mapped
1253 * during exec and are not mapped with the mmap system call.
1254 * Callers must hold down_write() on the mm's mmap_sem for these
1255 */
1256 void added_exe_file_vma(struct mm_struct *mm)
1257 {
1258 mm->num_exe_file_vmas++;
1259 }
1260
1261 void removed_exe_file_vma(struct mm_struct *mm)
1262 {
1263 mm->num_exe_file_vmas--;
1264 if ((mm->num_exe_file_vmas == 0) && mm->exe_file){
1265 fput(mm->exe_file);
1266 mm->exe_file = NULL;
1267 }
1268
1269 }
1270
1271 void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
1272 {
1273 if (new_exe_file)
1274 get_file(new_exe_file);
1275 if (mm->exe_file)
1276 fput(mm->exe_file);
1277 mm->exe_file = new_exe_file;
1278 mm->num_exe_file_vmas = 0;
1279 }
1280
1281 struct file *get_mm_exe_file(struct mm_struct *mm)
1282 {
1283 struct file *exe_file;
1284
1285 /* We need mmap_sem to protect against races with removal of
1286 * VM_EXECUTABLE vmas */
1287 down_read(&mm->mmap_sem);
1288 exe_file = mm->exe_file;
1289 if (exe_file)
1290 get_file(exe_file);
1291 up_read(&mm->mmap_sem);
1292 return exe_file;
1293 }
1294
1295 void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm)
1296 {
1297 /* It's safe to write the exe_file pointer without exe_file_lock because
1298 * this is called during fork when the task is not yet in /proc */
1299 newmm->exe_file = get_mm_exe_file(oldmm);
1300 }
1301
1302 static int proc_exe_link(struct inode *inode, struct path *exe_path)
1303 {
1304 struct task_struct *task;
1305 struct mm_struct *mm;
1306 struct file *exe_file;
1307
1308 task = get_proc_task(inode);
1309 if (!task)
1310 return -ENOENT;
1311 mm = get_task_mm(task);
1312 put_task_struct(task);
1313 if (!mm)
1314 return -ENOENT;
1315 exe_file = get_mm_exe_file(mm);
1316 mmput(mm);
1317 if (exe_file) {
1318 *exe_path = exe_file->f_path;
1319 path_get(&exe_file->f_path);
1320 fput(exe_file);
1321 return 0;
1322 } else
1323 return -ENOENT;
1324 }
1325
1326 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1327 {
1328 struct inode *inode = dentry->d_inode;
1329 int error = -EACCES;
1330
1331 /* We don't need a base pointer in the /proc filesystem */
1332 path_put(&nd->path);
1333
1334 /* Are we allowed to snoop on the tasks file descriptors? */
1335 if (!proc_fd_access_allowed(inode))
1336 goto out;
1337
1338 error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1339 nd->last_type = LAST_BIND;
1340 out:
1341 return ERR_PTR(error);
1342 }
1343
1344 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1345 {
1346 char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1347 char *pathname;
1348 int len;
1349
1350 if (!tmp)
1351 return -ENOMEM;
1352
1353 pathname = d_path(path, tmp, PAGE_SIZE);
1354 len = PTR_ERR(pathname);
1355 if (IS_ERR(pathname))
1356 goto out;
1357 len = tmp + PAGE_SIZE - 1 - pathname;
1358
1359 if (len > buflen)
1360 len = buflen;
1361 if (copy_to_user(buffer, pathname, len))
1362 len = -EFAULT;
1363 out:
1364 free_page((unsigned long)tmp);
1365 return len;
1366 }
1367
1368 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1369 {
1370 int error = -EACCES;
1371 struct inode *inode = dentry->d_inode;
1372 struct path path;
1373
1374 /* Are we allowed to snoop on the tasks file descriptors? */
1375 if (!proc_fd_access_allowed(inode))
1376 goto out;
1377
1378 error = PROC_I(inode)->op.proc_get_link(inode, &path);
1379 if (error)
1380 goto out;
1381
1382 error = do_proc_readlink(&path, buffer, buflen);
1383 path_put(&path);
1384 out:
1385 return error;
1386 }
1387
1388 static const struct inode_operations proc_pid_link_inode_operations = {
1389 .readlink = proc_pid_readlink,
1390 .follow_link = proc_pid_follow_link,
1391 .setattr = proc_setattr,
1392 };
1393
1394
1395 /* building an inode */
1396
1397 static int task_dumpable(struct task_struct *task)
1398 {
1399 int dumpable = 0;
1400 struct mm_struct *mm;
1401
1402 task_lock(task);
1403 mm = task->mm;
1404 if (mm)
1405 dumpable = get_dumpable(mm);
1406 task_unlock(task);
1407 if(dumpable == 1)
1408 return 1;
1409 return 0;
1410 }
1411
1412
1413 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1414 {
1415 struct inode * inode;
1416 struct proc_inode *ei;
1417
1418 /* We need a new inode */
1419
1420 inode = new_inode(sb);
1421 if (!inode)
1422 goto out;
1423
1424 /* Common stuff */
1425 ei = PROC_I(inode);
1426 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1427 inode->i_op = &proc_def_inode_operations;
1428
1429 /*
1430 * grab the reference to task.
1431 */
1432 ei->pid = get_task_pid(task, PIDTYPE_PID);
1433 if (!ei->pid)
1434 goto out_unlock;
1435
1436 inode->i_uid = 0;
1437 inode->i_gid = 0;
1438 if (task_dumpable(task)) {
1439 inode->i_uid = task->euid;
1440 inode->i_gid = task->egid;
1441 }
1442 security_task_to_inode(task, inode);
1443
1444 out:
1445 return inode;
1446
1447 out_unlock:
1448 iput(inode);
1449 return NULL;
1450 }
1451
1452 static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1453 {
1454 struct inode *inode = dentry->d_inode;
1455 struct task_struct *task;
1456 generic_fillattr(inode, stat);
1457
1458 rcu_read_lock();
1459 stat->uid = 0;
1460 stat->gid = 0;
1461 task = pid_task(proc_pid(inode), PIDTYPE_PID);
1462 if (task) {
1463 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1464 task_dumpable(task)) {
1465 stat->uid = task->euid;
1466 stat->gid = task->egid;
1467 }
1468 }
1469 rcu_read_unlock();
1470 return 0;
1471 }
1472
1473 /* dentry stuff */
1474
1475 /*
1476 * Exceptional case: normally we are not allowed to unhash a busy
1477 * directory. In this case, however, we can do it - no aliasing problems
1478 * due to the way we treat inodes.
1479 *
1480 * Rewrite the inode's ownerships here because the owning task may have
1481 * performed a setuid(), etc.
1482 *
1483 * Before the /proc/pid/status file was created the only way to read
1484 * the effective uid of a /process was to stat /proc/pid. Reading
1485 * /proc/pid/status is slow enough that procps and other packages
1486 * kept stating /proc/pid. To keep the rules in /proc simple I have
1487 * made this apply to all per process world readable and executable
1488 * directories.
1489 */
1490 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1491 {
1492 struct inode *inode = dentry->d_inode;
1493 struct task_struct *task = get_proc_task(inode);
1494 if (task) {
1495 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1496 task_dumpable(task)) {
1497 inode->i_uid = task->euid;
1498 inode->i_gid = task->egid;
1499 } else {
1500 inode->i_uid = 0;
1501 inode->i_gid = 0;
1502 }
1503 inode->i_mode &= ~(S_ISUID | S_ISGID);
1504 security_task_to_inode(task, inode);
1505 put_task_struct(task);
1506 return 1;
1507 }
1508 d_drop(dentry);
1509 return 0;
1510 }
1511
1512 static int pid_delete_dentry(struct dentry * dentry)
1513 {
1514 /* Is the task we represent dead?
1515 * If so, then don't put the dentry on the lru list,
1516 * kill it immediately.
1517 */
1518 return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1519 }
1520
1521 static struct dentry_operations pid_dentry_operations =
1522 {
1523 .d_revalidate = pid_revalidate,
1524 .d_delete = pid_delete_dentry,
1525 };
1526
1527 /* Lookups */
1528
1529 typedef struct dentry *instantiate_t(struct inode *, struct dentry *,
1530 struct task_struct *, const void *);
1531
1532 /*
1533 * Fill a directory entry.
1534 *
1535 * If possible create the dcache entry and derive our inode number and
1536 * file type from dcache entry.
1537 *
1538 * Since all of the proc inode numbers are dynamically generated, the inode
1539 * numbers do not exist until the inode is cache. This means creating the
1540 * the dcache entry in readdir is necessary to keep the inode numbers
1541 * reported by readdir in sync with the inode numbers reported
1542 * by stat.
1543 */
1544 static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1545 char *name, int len,
1546 instantiate_t instantiate, struct task_struct *task, const void *ptr)
1547 {
1548 struct dentry *child, *dir = filp->f_path.dentry;
1549 struct inode *inode;
1550 struct qstr qname;
1551 ino_t ino = 0;
1552 unsigned type = DT_UNKNOWN;
1553
1554 qname.name = name;
1555 qname.len = len;
1556 qname.hash = full_name_hash(name, len);
1557
1558 child = d_lookup(dir, &qname);
1559 if (!child) {
1560 struct dentry *new;
1561 new = d_alloc(dir, &qname);
1562 if (new) {
1563 child = instantiate(dir->d_inode, new, task, ptr);
1564 if (child)
1565 dput(new);
1566 else
1567 child = new;
1568 }
1569 }
1570 if (!child || IS_ERR(child) || !child->d_inode)
1571 goto end_instantiate;
1572 inode = child->d_inode;
1573 if (inode) {
1574 ino = inode->i_ino;
1575 type = inode->i_mode >> 12;
1576 }
1577 dput(child);
1578 end_instantiate:
1579 if (!ino)
1580 ino = find_inode_number(dir, &qname);
1581 if (!ino)
1582 ino = 1;
1583 return filldir(dirent, name, len, filp->f_pos, ino, type);
1584 }
1585
1586 static unsigned name_to_int(struct dentry *dentry)
1587 {
1588 const char *name = dentry->d_name.name;
1589 int len = dentry->d_name.len;
1590 unsigned n = 0;
1591
1592 if (len > 1 && *name == '0')
1593 goto out;
1594 while (len-- > 0) {
1595 unsigned c = *name++ - '0';
1596 if (c > 9)
1597 goto out;
1598 if (n >= (~0U-9)/10)
1599 goto out;
1600 n *= 10;
1601 n += c;
1602 }
1603 return n;
1604 out:
1605 return ~0U;
1606 }
1607
1608 #define PROC_FDINFO_MAX 64
1609
1610 static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1611 {
1612 struct task_struct *task = get_proc_task(inode);
1613 struct files_struct *files = NULL;
1614 struct file *file;
1615 int fd = proc_fd(inode);
1616
1617 if (task) {
1618 files = get_files_struct(task);
1619 put_task_struct(task);
1620 }
1621 if (files) {
1622 /*
1623 * We are not taking a ref to the file structure, so we must
1624 * hold ->file_lock.
1625 */
1626 spin_lock(&files->file_lock);
1627 file = fcheck_files(files, fd);
1628 if (file) {
1629 if (path) {
1630 *path = file->f_path;
1631 path_get(&file->f_path);
1632 }
1633 if (info)
1634 snprintf(info, PROC_FDINFO_MAX,
1635 "pos:\t%lli\n"
1636 "flags:\t0%o\n",
1637 (long long) file->f_pos,
1638 file->f_flags);
1639 spin_unlock(&files->file_lock);
1640 put_files_struct(files);
1641 return 0;
1642 }
1643 spin_unlock(&files->file_lock);
1644 put_files_struct(files);
1645 }
1646 return -ENOENT;
1647 }
1648
1649 static int proc_fd_link(struct inode *inode, struct path *path)
1650 {
1651 return proc_fd_info(inode, path, NULL);
1652 }
1653
1654 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1655 {
1656 struct inode *inode = dentry->d_inode;
1657 struct task_struct *task = get_proc_task(inode);
1658 int fd = proc_fd(inode);
1659 struct files_struct *files;
1660
1661 if (task) {
1662 files = get_files_struct(task);
1663 if (files) {
1664 rcu_read_lock();
1665 if (fcheck_files(files, fd)) {
1666 rcu_read_unlock();
1667 put_files_struct(files);
1668 if (task_dumpable(task)) {
1669 inode->i_uid = task->euid;
1670 inode->i_gid = task->egid;
1671 } else {
1672 inode->i_uid = 0;
1673 inode->i_gid = 0;
1674 }
1675 inode->i_mode &= ~(S_ISUID | S_ISGID);
1676 security_task_to_inode(task, inode);
1677 put_task_struct(task);
1678 return 1;
1679 }
1680 rcu_read_unlock();
1681 put_files_struct(files);
1682 }
1683 put_task_struct(task);
1684 }
1685 d_drop(dentry);
1686 return 0;
1687 }
1688
1689 static struct dentry_operations tid_fd_dentry_operations =
1690 {
1691 .d_revalidate = tid_fd_revalidate,
1692 .d_delete = pid_delete_dentry,
1693 };
1694
1695 static struct dentry *proc_fd_instantiate(struct inode *dir,
1696 struct dentry *dentry, struct task_struct *task, const void *ptr)
1697 {
1698 unsigned fd = *(const unsigned *)ptr;
1699 struct file *file;
1700 struct files_struct *files;
1701 struct inode *inode;
1702 struct proc_inode *ei;
1703 struct dentry *error = ERR_PTR(-ENOENT);
1704
1705 inode = proc_pid_make_inode(dir->i_sb, task);
1706 if (!inode)
1707 goto out;
1708 ei = PROC_I(inode);
1709 ei->fd = fd;
1710 files = get_files_struct(task);
1711 if (!files)
1712 goto out_iput;
1713 inode->i_mode = S_IFLNK;
1714
1715 /*
1716 * We are not taking a ref to the file structure, so we must
1717 * hold ->file_lock.
1718 */
1719 spin_lock(&files->file_lock);
1720 file = fcheck_files(files, fd);
1721 if (!file)
1722 goto out_unlock;
1723 if (file->f_mode & 1)
1724 inode->i_mode |= S_IRUSR | S_IXUSR;
1725 if (file->f_mode & 2)
1726 inode->i_mode |= S_IWUSR | S_IXUSR;
1727 spin_unlock(&files->file_lock);
1728 put_files_struct(files);
1729
1730 inode->i_op = &proc_pid_link_inode_operations;
1731 inode->i_size = 64;
1732 ei->op.proc_get_link = proc_fd_link;
1733 dentry->d_op = &tid_fd_dentry_operations;
1734 d_add(dentry, inode);
1735 /* Close the race of the process dying before we return the dentry */
1736 if (tid_fd_revalidate(dentry, NULL))
1737 error = NULL;
1738
1739 out:
1740 return error;
1741 out_unlock:
1742 spin_unlock(&files->file_lock);
1743 put_files_struct(files);
1744 out_iput:
1745 iput(inode);
1746 goto out;
1747 }
1748
1749 static struct dentry *proc_lookupfd_common(struct inode *dir,
1750 struct dentry *dentry,
1751 instantiate_t instantiate)
1752 {
1753 struct task_struct *task = get_proc_task(dir);
1754 unsigned fd = name_to_int(dentry);
1755 struct dentry *result = ERR_PTR(-ENOENT);
1756
1757 if (!task)
1758 goto out_no_task;
1759 if (fd == ~0U)
1760 goto out;
1761
1762 result = instantiate(dir, dentry, task, &fd);
1763 out:
1764 put_task_struct(task);
1765 out_no_task:
1766 return result;
1767 }
1768
1769 static int proc_readfd_common(struct file * filp, void * dirent,
1770 filldir_t filldir, instantiate_t instantiate)
1771 {
1772 struct dentry *dentry = filp->f_path.dentry;
1773 struct inode *inode = dentry->d_inode;
1774 struct task_struct *p = get_proc_task(inode);
1775 unsigned int fd, ino;
1776 int retval;
1777 struct files_struct * files;
1778
1779 retval = -ENOENT;
1780 if (!p)
1781 goto out_no_task;
1782 retval = 0;
1783
1784 fd = filp->f_pos;
1785 switch (fd) {
1786 case 0:
1787 if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1788 goto out;
1789 filp->f_pos++;
1790 case 1:
1791 ino = parent_ino(dentry);
1792 if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1793 goto out;
1794 filp->f_pos++;
1795 default:
1796 files = get_files_struct(p);
1797 if (!files)
1798 goto out;
1799 rcu_read_lock();
1800 for (fd = filp->f_pos-2;
1801 fd < files_fdtable(files)->max_fds;
1802 fd++, filp->f_pos++) {
1803 char name[PROC_NUMBUF];
1804 int len;
1805
1806 if (!fcheck_files(files, fd))
1807 continue;
1808 rcu_read_unlock();
1809
1810 len = snprintf(name, sizeof(name), "%d", fd);
1811 if (proc_fill_cache(filp, dirent, filldir,
1812 name, len, instantiate,
1813 p, &fd) < 0) {
1814 rcu_read_lock();
1815 break;
1816 }
1817 rcu_read_lock();
1818 }
1819 rcu_read_unlock();
1820 put_files_struct(files);
1821 }
1822 out:
1823 put_task_struct(p);
1824 out_no_task:
1825 return retval;
1826 }
1827
1828 static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
1829 struct nameidata *nd)
1830 {
1831 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
1832 }
1833
1834 static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
1835 {
1836 return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
1837 }
1838
1839 static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
1840 size_t len, loff_t *ppos)
1841 {
1842 char tmp[PROC_FDINFO_MAX];
1843 int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
1844 if (!err)
1845 err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
1846 return err;
1847 }
1848
1849 static const struct file_operations proc_fdinfo_file_operations = {
1850 .open = nonseekable_open,
1851 .read = proc_fdinfo_read,
1852 };
1853
1854 static const struct file_operations proc_fd_operations = {
1855 .read = generic_read_dir,
1856 .readdir = proc_readfd,
1857 };
1858
1859 /*
1860 * /proc/pid/fd needs a special permission handler so that a process can still
1861 * access /proc/self/fd after it has executed a setuid().
1862 */
1863 static int proc_fd_permission(struct inode *inode, int mask)
1864 {
1865 int rv;
1866
1867 rv = generic_permission(inode, mask, NULL);
1868 if (rv == 0)
1869 return 0;
1870 if (task_pid(current) == proc_pid(inode))
1871 rv = 0;
1872 return rv;
1873 }
1874
1875 /*
1876 * proc directories can do almost nothing..
1877 */
1878 static const struct inode_operations proc_fd_inode_operations = {
1879 .lookup = proc_lookupfd,
1880 .permission = proc_fd_permission,
1881 .setattr = proc_setattr,
1882 };
1883
1884 static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
1885 struct dentry *dentry, struct task_struct *task, const void *ptr)
1886 {
1887 unsigned fd = *(unsigned *)ptr;
1888 struct inode *inode;
1889 struct proc_inode *ei;
1890 struct dentry *error = ERR_PTR(-ENOENT);
1891
1892 inode = proc_pid_make_inode(dir->i_sb, task);
1893 if (!inode)
1894 goto out;
1895 ei = PROC_I(inode);
1896 ei->fd = fd;
1897 inode->i_mode = S_IFREG | S_IRUSR;
1898 inode->i_fop = &proc_fdinfo_file_operations;
1899 dentry->d_op = &tid_fd_dentry_operations;
1900 d_add(dentry, inode);
1901 /* Close the race of the process dying before we return the dentry */
1902 if (tid_fd_revalidate(dentry, NULL))
1903 error = NULL;
1904
1905 out:
1906 return error;
1907 }
1908
1909 static struct dentry *proc_lookupfdinfo(struct inode *dir,
1910 struct dentry *dentry,
1911 struct nameidata *nd)
1912 {
1913 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
1914 }
1915
1916 static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
1917 {
1918 return proc_readfd_common(filp, dirent, filldir,
1919 proc_fdinfo_instantiate);
1920 }
1921
1922 static const struct file_operations proc_fdinfo_operations = {
1923 .read = generic_read_dir,
1924 .readdir = proc_readfdinfo,
1925 };
1926
1927 /*
1928 * proc directories can do almost nothing..
1929 */
1930 static const struct inode_operations proc_fdinfo_inode_operations = {
1931 .lookup = proc_lookupfdinfo,
1932 .setattr = proc_setattr,
1933 };
1934
1935
1936 static struct dentry *proc_pident_instantiate(struct inode *dir,
1937 struct dentry *dentry, struct task_struct *task, const void *ptr)
1938 {
1939 const struct pid_entry *p = ptr;
1940 struct inode *inode;
1941 struct proc_inode *ei;
1942 struct dentry *error = ERR_PTR(-EINVAL);
1943
1944 inode = proc_pid_make_inode(dir->i_sb, task);
1945 if (!inode)
1946 goto out;
1947
1948 ei = PROC_I(inode);
1949 inode->i_mode = p->mode;
1950 if (S_ISDIR(inode->i_mode))
1951 inode->i_nlink = 2; /* Use getattr to fix if necessary */
1952 if (p->iop)
1953 inode->i_op = p->iop;
1954 if (p->fop)
1955 inode->i_fop = p->fop;
1956 ei->op = p->op;
1957 dentry->d_op = &pid_dentry_operations;
1958 d_add(dentry, inode);
1959 /* Close the race of the process dying before we return the dentry */
1960 if (pid_revalidate(dentry, NULL))
1961 error = NULL;
1962 out:
1963 return error;
1964 }
1965
1966 static struct dentry *proc_pident_lookup(struct inode *dir,
1967 struct dentry *dentry,
1968 const struct pid_entry *ents,
1969 unsigned int nents)
1970 {
1971 struct inode *inode;
1972 struct dentry *error;
1973 struct task_struct *task = get_proc_task(dir);
1974 const struct pid_entry *p, *last;
1975
1976 error = ERR_PTR(-ENOENT);
1977 inode = NULL;
1978
1979 if (!task)
1980 goto out_no_task;
1981
1982 /*
1983 * Yes, it does not scale. And it should not. Don't add
1984 * new entries into /proc/<tgid>/ without very good reasons.
1985 */
1986 last = &ents[nents - 1];
1987 for (p = ents; p <= last; p++) {
1988 if (p->len != dentry->d_name.len)
1989 continue;
1990 if (!memcmp(dentry->d_name.name, p->name, p->len))
1991 break;
1992 }
1993 if (p > last)
1994 goto out;
1995
1996 error = proc_pident_instantiate(dir, dentry, task, p);
1997 out:
1998 put_task_struct(task);
1999 out_no_task:
2000 return error;
2001 }
2002
2003 static int proc_pident_fill_cache(struct file *filp, void *dirent,
2004 filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2005 {
2006 return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2007 proc_pident_instantiate, task, p);
2008 }
2009
2010 static int proc_pident_readdir(struct file *filp,
2011 void *dirent, filldir_t filldir,
2012 const struct pid_entry *ents, unsigned int nents)
2013 {
2014 int i;
2015 struct dentry *dentry = filp->f_path.dentry;
2016 struct inode *inode = dentry->d_inode;
2017 struct task_struct *task = get_proc_task(inode);
2018 const struct pid_entry *p, *last;
2019 ino_t ino;
2020 int ret;
2021
2022 ret = -ENOENT;
2023 if (!task)
2024 goto out_no_task;
2025
2026 ret = 0;
2027 i = filp->f_pos;
2028 switch (i) {
2029 case 0:
2030 ino = inode->i_ino;
2031 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2032 goto out;
2033 i++;
2034 filp->f_pos++;
2035 /* fall through */
2036 case 1:
2037 ino = parent_ino(dentry);
2038 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2039 goto out;
2040 i++;
2041 filp->f_pos++;
2042 /* fall through */
2043 default:
2044 i -= 2;
2045 if (i >= nents) {
2046 ret = 1;
2047 goto out;
2048 }
2049 p = ents + i;
2050 last = &ents[nents - 1];
2051 while (p <= last) {
2052 if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2053 goto out;
2054 filp->f_pos++;
2055 p++;
2056 }
2057 }
2058
2059 ret = 1;
2060 out:
2061 put_task_struct(task);
2062 out_no_task:
2063 return ret;
2064 }
2065
2066 #ifdef CONFIG_SECURITY
2067 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2068 size_t count, loff_t *ppos)
2069 {
2070 struct inode * inode = file->f_path.dentry->d_inode;
2071 char *p = NULL;
2072 ssize_t length;
2073 struct task_struct *task = get_proc_task(inode);
2074
2075 if (!task)
2076 return -ESRCH;
2077
2078 length = security_getprocattr(task,
2079 (char*)file->f_path.dentry->d_name.name,
2080 &p);
2081 put_task_struct(task);
2082 if (length > 0)
2083 length = simple_read_from_buffer(buf, count, ppos, p, length);
2084 kfree(p);
2085 return length;
2086 }
2087
2088 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2089 size_t count, loff_t *ppos)
2090 {
2091 struct inode * inode = file->f_path.dentry->d_inode;
2092 char *page;
2093 ssize_t length;
2094 struct task_struct *task = get_proc_task(inode);
2095
2096 length = -ESRCH;
2097 if (!task)
2098 goto out_no_task;
2099 if (count > PAGE_SIZE)
2100 count = PAGE_SIZE;
2101
2102 /* No partial writes. */
2103 length = -EINVAL;
2104 if (*ppos != 0)
2105 goto out;
2106
2107 length = -ENOMEM;
2108 page = (char*)__get_free_page(GFP_TEMPORARY);
2109 if (!page)
2110 goto out;
2111
2112 length = -EFAULT;
2113 if (copy_from_user(page, buf, count))
2114 goto out_free;
2115
2116 length = security_setprocattr(task,
2117 (char*)file->f_path.dentry->d_name.name,
2118 (void*)page, count);
2119 out_free:
2120 free_page((unsigned long) page);
2121 out:
2122 put_task_struct(task);
2123 out_no_task:
2124 return length;
2125 }
2126
2127 static const struct file_operations proc_pid_attr_operations = {
2128 .read = proc_pid_attr_read,
2129 .write = proc_pid_attr_write,
2130 };
2131
2132 static const struct pid_entry attr_dir_stuff[] = {
2133 REG("current", S_IRUGO|S_IWUGO, pid_attr),
2134 REG("prev", S_IRUGO, pid_attr),
2135 REG("exec", S_IRUGO|S_IWUGO, pid_attr),
2136 REG("fscreate", S_IRUGO|S_IWUGO, pid_attr),
2137 REG("keycreate", S_IRUGO|S_IWUGO, pid_attr),
2138 REG("sockcreate", S_IRUGO|S_IWUGO, pid_attr),
2139 };
2140
2141 static int proc_attr_dir_readdir(struct file * filp,
2142 void * dirent, filldir_t filldir)
2143 {
2144 return proc_pident_readdir(filp,dirent,filldir,
2145 attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2146 }
2147
2148 static const struct file_operations proc_attr_dir_operations = {
2149 .read = generic_read_dir,
2150 .readdir = proc_attr_dir_readdir,
2151 };
2152
2153 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2154 struct dentry *dentry, struct nameidata *nd)
2155 {
2156 return proc_pident_lookup(dir, dentry,
2157 attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2158 }
2159
2160 static const struct inode_operations proc_attr_dir_inode_operations = {
2161 .lookup = proc_attr_dir_lookup,
2162 .getattr = pid_getattr,
2163 .setattr = proc_setattr,
2164 };
2165
2166 #endif
2167
2168 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
2169 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2170 size_t count, loff_t *ppos)
2171 {
2172 struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2173 struct mm_struct *mm;
2174 char buffer[PROC_NUMBUF];
2175 size_t len;
2176 int ret;
2177
2178 if (!task)
2179 return -ESRCH;
2180
2181 ret = 0;
2182 mm = get_task_mm(task);
2183 if (mm) {
2184 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2185 ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2186 MMF_DUMP_FILTER_SHIFT));
2187 mmput(mm);
2188 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2189 }
2190
2191 put_task_struct(task);
2192
2193 return ret;
2194 }
2195
2196 static ssize_t proc_coredump_filter_write(struct file *file,
2197 const char __user *buf,
2198 size_t count,
2199 loff_t *ppos)
2200 {
2201 struct task_struct *task;
2202 struct mm_struct *mm;
2203 char buffer[PROC_NUMBUF], *end;
2204 unsigned int val;
2205 int ret;
2206 int i;
2207 unsigned long mask;
2208
2209 ret = -EFAULT;
2210 memset(buffer, 0, sizeof(buffer));
2211 if (count > sizeof(buffer) - 1)
2212 count = sizeof(buffer) - 1;
2213 if (copy_from_user(buffer, buf, count))
2214 goto out_no_task;
2215
2216 ret = -EINVAL;
2217 val = (unsigned int)simple_strtoul(buffer, &end, 0);
2218 if (*end == '\n')
2219 end++;
2220 if (end - buffer == 0)
2221 goto out_no_task;
2222
2223 ret = -ESRCH;
2224 task = get_proc_task(file->f_dentry->d_inode);
2225 if (!task)
2226 goto out_no_task;
2227
2228 ret = end - buffer;
2229 mm = get_task_mm(task);
2230 if (!mm)
2231 goto out_no_mm;
2232
2233 for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2234 if (val & mask)
2235 set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2236 else
2237 clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2238 }
2239
2240 mmput(mm);
2241 out_no_mm:
2242 put_task_struct(task);
2243 out_no_task:
2244 return ret;
2245 }
2246
2247 static const struct file_operations proc_coredump_filter_operations = {
2248 .read = proc_coredump_filter_read,
2249 .write = proc_coredump_filter_write,
2250 };
2251 #endif
2252
2253 /*
2254 * /proc/self:
2255 */
2256 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2257 int buflen)
2258 {
2259 struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2260 pid_t tgid = task_tgid_nr_ns(current, ns);
2261 char tmp[PROC_NUMBUF];
2262 if (!tgid)
2263 return -ENOENT;
2264 sprintf(tmp, "%d", tgid);
2265 return vfs_readlink(dentry,buffer,buflen,tmp);
2266 }
2267
2268 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2269 {
2270 struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2271 pid_t tgid = task_tgid_nr_ns(current, ns);
2272 char tmp[PROC_NUMBUF];
2273 if (!tgid)
2274 return ERR_PTR(-ENOENT);
2275 sprintf(tmp, "%d", task_tgid_nr_ns(current, ns));
2276 return ERR_PTR(vfs_follow_link(nd,tmp));
2277 }
2278
2279 static const struct inode_operations proc_self_inode_operations = {
2280 .readlink = proc_self_readlink,
2281 .follow_link = proc_self_follow_link,
2282 };
2283
2284 /*
2285 * proc base
2286 *
2287 * These are the directory entries in the root directory of /proc
2288 * that properly belong to the /proc filesystem, as they describe
2289 * describe something that is process related.
2290 */
2291 static const struct pid_entry proc_base_stuff[] = {
2292 NOD("self", S_IFLNK|S_IRWXUGO,
2293 &proc_self_inode_operations, NULL, {}),
2294 };
2295
2296 /*
2297 * Exceptional case: normally we are not allowed to unhash a busy
2298 * directory. In this case, however, we can do it - no aliasing problems
2299 * due to the way we treat inodes.
2300 */
2301 static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd)
2302 {
2303 struct inode *inode = dentry->d_inode;
2304 struct task_struct *task = get_proc_task(inode);
2305 if (task) {
2306 put_task_struct(task);
2307 return 1;
2308 }
2309 d_drop(dentry);
2310 return 0;
2311 }
2312
2313 static struct dentry_operations proc_base_dentry_operations =
2314 {
2315 .d_revalidate = proc_base_revalidate,
2316 .d_delete = pid_delete_dentry,
2317 };
2318
2319 static struct dentry *proc_base_instantiate(struct inode *dir,
2320 struct dentry *dentry, struct task_struct *task, const void *ptr)
2321 {
2322 const struct pid_entry *p = ptr;
2323 struct inode *inode;
2324 struct proc_inode *ei;
2325 struct dentry *error = ERR_PTR(-EINVAL);
2326
2327 /* Allocate the inode */
2328 error = ERR_PTR(-ENOMEM);
2329 inode = new_inode(dir->i_sb);
2330 if (!inode)
2331 goto out;
2332
2333 /* Initialize the inode */
2334 ei = PROC_I(inode);
2335 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2336
2337 /*
2338 * grab the reference to the task.
2339 */
2340 ei->pid = get_task_pid(task, PIDTYPE_PID);
2341 if (!ei->pid)
2342 goto out_iput;
2343
2344 inode->i_uid = 0;
2345 inode->i_gid = 0;
2346 inode->i_mode = p->mode;
2347 if (S_ISDIR(inode->i_mode))
2348 inode->i_nlink = 2;
2349 if (S_ISLNK(inode->i_mode))
2350 inode->i_size = 64;
2351 if (p->iop)
2352 inode->i_op = p->iop;
2353 if (p->fop)
2354 inode->i_fop = p->fop;
2355 ei->op = p->op;
2356 dentry->d_op = &proc_base_dentry_operations;
2357 d_add(dentry, inode);
2358 error = NULL;
2359 out:
2360 return error;
2361 out_iput:
2362 iput(inode);
2363 goto out;
2364 }
2365
2366 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2367 {
2368 struct dentry *error;
2369 struct task_struct *task = get_proc_task(dir);
2370 const struct pid_entry *p, *last;
2371
2372 error = ERR_PTR(-ENOENT);
2373
2374 if (!task)
2375 goto out_no_task;
2376
2377 /* Lookup the directory entry */
2378 last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2379 for (p = proc_base_stuff; p <= last; p++) {
2380 if (p->len != dentry->d_name.len)
2381 continue;
2382 if (!memcmp(dentry->d_name.name, p->name, p->len))
2383 break;
2384 }
2385 if (p > last)
2386 goto out;
2387
2388 error = proc_base_instantiate(dir, dentry, task, p);
2389
2390 out:
2391 put_task_struct(task);
2392 out_no_task:
2393 return error;
2394 }
2395
2396 static int proc_base_fill_cache(struct file *filp, void *dirent,
2397 filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2398 {
2399 return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2400 proc_base_instantiate, task, p);
2401 }
2402
2403 #ifdef CONFIG_TASK_IO_ACCOUNTING
2404 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2405 {
2406 struct task_io_accounting acct = task->ioac;
2407 unsigned long flags;
2408
2409 if (whole && lock_task_sighand(task, &flags)) {
2410 struct task_struct *t = task;
2411
2412 task_io_accounting_add(&acct, &task->signal->ioac);
2413 while_each_thread(task, t)
2414 task_io_accounting_add(&acct, &t->ioac);
2415
2416 unlock_task_sighand(task, &flags);
2417 }
2418 return sprintf(buffer,
2419 "rchar: %llu\n"
2420 "wchar: %llu\n"
2421 "syscr: %llu\n"
2422 "syscw: %llu\n"
2423 "read_bytes: %llu\n"
2424 "write_bytes: %llu\n"
2425 "cancelled_write_bytes: %llu\n",
2426 acct.rchar, acct.wchar,
2427 acct.syscr, acct.syscw,
2428 acct.read_bytes, acct.write_bytes,
2429 acct.cancelled_write_bytes);
2430 }
2431
2432 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2433 {
2434 return do_io_accounting(task, buffer, 0);
2435 }
2436
2437 static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2438 {
2439 return do_io_accounting(task, buffer, 1);
2440 }
2441 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2442
2443 /*
2444 * Thread groups
2445 */
2446 static const struct file_operations proc_task_operations;
2447 static const struct inode_operations proc_task_inode_operations;
2448
2449 static const struct pid_entry tgid_base_stuff[] = {
2450 DIR("task", S_IRUGO|S_IXUGO, task),
2451 DIR("fd", S_IRUSR|S_IXUSR, fd),
2452 DIR("fdinfo", S_IRUSR|S_IXUSR, fdinfo),
2453 #ifdef CONFIG_NET
2454 DIR("net", S_IRUGO|S_IXUGO, net),
2455 #endif
2456 REG("environ", S_IRUSR, environ),
2457 INF("auxv", S_IRUSR, pid_auxv),
2458 ONE("status", S_IRUGO, pid_status),
2459 INF("limits", S_IRUSR, pid_limits),
2460 #ifdef CONFIG_SCHED_DEBUG
2461 REG("sched", S_IRUGO|S_IWUSR, pid_sched),
2462 #endif
2463 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2464 INF("syscall", S_IRUSR, pid_syscall),
2465 #endif
2466 INF("cmdline", S_IRUGO, pid_cmdline),
2467 ONE("stat", S_IRUGO, tgid_stat),
2468 ONE("statm", S_IRUGO, pid_statm),
2469 REG("maps", S_IRUGO, maps),
2470 #ifdef CONFIG_NUMA
2471 REG("numa_maps", S_IRUGO, numa_maps),
2472 #endif
2473 REG("mem", S_IRUSR|S_IWUSR, mem),
2474 LNK("cwd", cwd),
2475 LNK("root", root),
2476 LNK("exe", exe),
2477 REG("mounts", S_IRUGO, mounts),
2478 REG("mountinfo", S_IRUGO, mountinfo),
2479 REG("mountstats", S_IRUSR, mountstats),
2480 #ifdef CONFIG_PROC_PAGE_MONITOR
2481 REG("clear_refs", S_IWUSR, clear_refs),
2482 REG("smaps", S_IRUGO, smaps),
2483 REG("pagemap", S_IRUSR, pagemap),
2484 #endif
2485 #ifdef CONFIG_SECURITY
2486 DIR("attr", S_IRUGO|S_IXUGO, attr_dir),
2487 #endif
2488 #ifdef CONFIG_KALLSYMS
2489 INF("wchan", S_IRUGO, pid_wchan),
2490 #endif
2491 #ifdef CONFIG_SCHEDSTATS
2492 INF("schedstat", S_IRUGO, pid_schedstat),
2493 #endif
2494 #ifdef CONFIG_LATENCYTOP
2495 REG("latency", S_IRUGO, lstats),
2496 #endif
2497 #ifdef CONFIG_PROC_PID_CPUSET
2498 REG("cpuset", S_IRUGO, cpuset),
2499 #endif
2500 #ifdef CONFIG_CGROUPS
2501 REG("cgroup", S_IRUGO, cgroup),
2502 #endif
2503 INF("oom_score", S_IRUGO, oom_score),
2504 REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust),
2505 #ifdef CONFIG_AUDITSYSCALL
2506 REG("loginuid", S_IWUSR|S_IRUGO, loginuid),
2507 REG("sessionid", S_IRUGO, sessionid),
2508 #endif
2509 #ifdef CONFIG_FAULT_INJECTION
2510 REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject),
2511 #endif
2512 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
2513 REG("coredump_filter", S_IRUGO|S_IWUSR, coredump_filter),
2514 #endif
2515 #ifdef CONFIG_TASK_IO_ACCOUNTING
2516 INF("io", S_IRUGO, tgid_io_accounting),
2517 #endif
2518 };
2519
2520 static int proc_tgid_base_readdir(struct file * filp,
2521 void * dirent, filldir_t filldir)
2522 {
2523 return proc_pident_readdir(filp,dirent,filldir,
2524 tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2525 }
2526
2527 static const struct file_operations proc_tgid_base_operations = {
2528 .read = generic_read_dir,
2529 .readdir = proc_tgid_base_readdir,
2530 };
2531
2532 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2533 return proc_pident_lookup(dir, dentry,
2534 tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2535 }
2536
2537 static const struct inode_operations proc_tgid_base_inode_operations = {
2538 .lookup = proc_tgid_base_lookup,
2539 .getattr = pid_getattr,
2540 .setattr = proc_setattr,
2541 };
2542
2543 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2544 {
2545 struct dentry *dentry, *leader, *dir;
2546 char buf[PROC_NUMBUF];
2547 struct qstr name;
2548
2549 name.name = buf;
2550 name.len = snprintf(buf, sizeof(buf), "%d", pid);
2551 dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2552 if (dentry) {
2553 if (!(current->flags & PF_EXITING))
2554 shrink_dcache_parent(dentry);
2555 d_drop(dentry);
2556 dput(dentry);
2557 }
2558
2559 if (tgid == 0)
2560 goto out;
2561
2562 name.name = buf;
2563 name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2564 leader = d_hash_and_lookup(mnt->mnt_root, &name);
2565 if (!leader)
2566 goto out;
2567
2568 name.name = "task";
2569 name.len = strlen(name.name);
2570 dir = d_hash_and_lookup(leader, &name);
2571 if (!dir)
2572 goto out_put_leader;
2573
2574 name.name = buf;
2575 name.len = snprintf(buf, sizeof(buf), "%d", pid);
2576 dentry = d_hash_and_lookup(dir, &name);
2577 if (dentry) {
2578 shrink_dcache_parent(dentry);
2579 d_drop(dentry);
2580 dput(dentry);
2581 }
2582
2583 dput(dir);
2584 out_put_leader:
2585 dput(leader);
2586 out:
2587 return;
2588 }
2589
2590 /**
2591 * proc_flush_task - Remove dcache entries for @task from the /proc dcache.
2592 * @task: task that should be flushed.
2593 *
2594 * When flushing dentries from proc, one needs to flush them from global
2595 * proc (proc_mnt) and from all the namespaces' procs this task was seen
2596 * in. This call is supposed to do all of this job.
2597 *
2598 * Looks in the dcache for
2599 * /proc/@pid
2600 * /proc/@tgid/task/@pid
2601 * if either directory is present flushes it and all of it'ts children
2602 * from the dcache.
2603 *
2604 * It is safe and reasonable to cache /proc entries for a task until
2605 * that task exits. After that they just clog up the dcache with
2606 * useless entries, possibly causing useful dcache entries to be
2607 * flushed instead. This routine is proved to flush those useless
2608 * dcache entries at process exit time.
2609 *
2610 * NOTE: This routine is just an optimization so it does not guarantee
2611 * that no dcache entries will exist at process exit time it
2612 * just makes it very unlikely that any will persist.
2613 */
2614
2615 void proc_flush_task(struct task_struct *task)
2616 {
2617 int i;
2618 struct pid *pid, *tgid = NULL;
2619 struct upid *upid;
2620
2621 pid = task_pid(task);
2622 if (thread_group_leader(task))
2623 tgid = task_tgid(task);
2624
2625 for (i = 0; i <= pid->level; i++) {
2626 upid = &pid->numbers[i];
2627 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2628 tgid ? tgid->numbers[i].nr : 0);
2629 }
2630
2631 upid = &pid->numbers[pid->level];
2632 if (upid->nr == 1)
2633 pid_ns_release_proc(upid->ns);
2634 }
2635
2636 static struct dentry *proc_pid_instantiate(struct inode *dir,
2637 struct dentry * dentry,
2638 struct task_struct *task, const void *ptr)
2639 {
2640 struct dentry *error = ERR_PTR(-ENOENT);
2641 struct inode *inode;
2642
2643 inode = proc_pid_make_inode(dir->i_sb, task);
2644 if (!inode)
2645 goto out;
2646
2647 inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2648 inode->i_op = &proc_tgid_base_inode_operations;
2649 inode->i_fop = &proc_tgid_base_operations;
2650 inode->i_flags|=S_IMMUTABLE;
2651
2652 inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
2653 ARRAY_SIZE(tgid_base_stuff));
2654
2655 dentry->d_op = &pid_dentry_operations;
2656
2657 d_add(dentry, inode);
2658 /* Close the race of the process dying before we return the dentry */
2659 if (pid_revalidate(dentry, NULL))
2660 error = NULL;
2661 out:
2662 return error;
2663 }
2664
2665 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2666 {
2667 struct dentry *result = ERR_PTR(-ENOENT);
2668 struct task_struct *task;
2669 unsigned tgid;
2670 struct pid_namespace *ns;
2671
2672 result = proc_base_lookup(dir, dentry);
2673 if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
2674 goto out;
2675
2676 tgid = name_to_int(dentry);
2677 if (tgid == ~0U)
2678 goto out;
2679
2680 ns = dentry->d_sb->s_fs_info;
2681 rcu_read_lock();
2682 task = find_task_by_pid_ns(tgid, ns);
2683 if (task)
2684 get_task_struct(task);
2685 rcu_read_unlock();
2686 if (!task)
2687 goto out;
2688
2689 result = proc_pid_instantiate(dir, dentry, task, NULL);
2690 put_task_struct(task);
2691 out:
2692 return result;
2693 }
2694
2695 /*
2696 * Find the first task with tgid >= tgid
2697 *
2698 */
2699 struct tgid_iter {
2700 unsigned int tgid;
2701 struct task_struct *task;
2702 };
2703 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
2704 {
2705 struct pid *pid;
2706
2707 if (iter.task)
2708 put_task_struct(iter.task);
2709 rcu_read_lock();
2710 retry:
2711 iter.task = NULL;
2712 pid = find_ge_pid(iter.tgid, ns);
2713 if (pid) {
2714 iter.tgid = pid_nr_ns(pid, ns);
2715 iter.task = pid_task(pid, PIDTYPE_PID);
2716 /* What we to know is if the pid we have find is the
2717 * pid of a thread_group_leader. Testing for task
2718 * being a thread_group_leader is the obvious thing
2719 * todo but there is a window when it fails, due to
2720 * the pid transfer logic in de_thread.
2721 *
2722 * So we perform the straight forward test of seeing
2723 * if the pid we have found is the pid of a thread
2724 * group leader, and don't worry if the task we have
2725 * found doesn't happen to be a thread group leader.
2726 * As we don't care in the case of readdir.
2727 */
2728 if (!iter.task || !has_group_leader_pid(iter.task)) {
2729 iter.tgid += 1;
2730 goto retry;
2731 }
2732 get_task_struct(iter.task);
2733 }
2734 rcu_read_unlock();
2735 return iter;
2736 }
2737
2738 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
2739
2740 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
2741 struct tgid_iter iter)
2742 {
2743 char name[PROC_NUMBUF];
2744 int len = snprintf(name, sizeof(name), "%d", iter.tgid);
2745 return proc_fill_cache(filp, dirent, filldir, name, len,
2746 proc_pid_instantiate, iter.task, NULL);
2747 }
2748
2749 /* for the /proc/ directory itself, after non-process stuff has been done */
2750 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2751 {
2752 unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2753 struct task_struct *reaper = get_proc_task(filp->f_path.dentry->d_inode);
2754 struct tgid_iter iter;
2755 struct pid_namespace *ns;
2756
2757 if (!reaper)
2758 goto out_no_task;
2759
2760 for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
2761 const struct pid_entry *p = &proc_base_stuff[nr];
2762 if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
2763 goto out;
2764 }
2765
2766 ns = filp->f_dentry->d_sb->s_fs_info;
2767 iter.task = NULL;
2768 iter.tgid = filp->f_pos - TGID_OFFSET;
2769 for (iter = next_tgid(ns, iter);
2770 iter.task;
2771 iter.tgid += 1, iter = next_tgid(ns, iter)) {
2772 filp->f_pos = iter.tgid + TGID_OFFSET;
2773 if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
2774 put_task_struct(iter.task);
2775 goto out;
2776 }
2777 }
2778 filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
2779 out:
2780 put_task_struct(reaper);
2781 out_no_task:
2782 return 0;
2783 }
2784
2785 /*
2786 * Tasks
2787 */
2788 static const struct pid_entry tid_base_stuff[] = {
2789 DIR("fd", S_IRUSR|S_IXUSR, fd),
2790 DIR("fdinfo", S_IRUSR|S_IXUSR, fdinfo),
2791 REG("environ", S_IRUSR, environ),
2792 INF("auxv", S_IRUSR, pid_auxv),
2793 ONE("status", S_IRUGO, pid_status),
2794 INF("limits", S_IRUSR, pid_limits),
2795 #ifdef CONFIG_SCHED_DEBUG
2796 REG("sched", S_IRUGO|S_IWUSR, pid_sched),
2797 #endif
2798 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
2799 INF("syscall", S_IRUSR, pid_syscall),
2800 #endif
2801 INF("cmdline", S_IRUGO, pid_cmdline),
2802 ONE("stat", S_IRUGO, tid_stat),
2803 ONE("statm", S_IRUGO, pid_statm),
2804 REG("maps", S_IRUGO, maps),
2805 #ifdef CONFIG_NUMA
2806 REG("numa_maps", S_IRUGO, numa_maps),
2807 #endif
2808 REG("mem", S_IRUSR|S_IWUSR, mem),
2809 LNK("cwd", cwd),
2810 LNK("root", root),
2811 LNK("exe", exe),
2812 REG("mounts", S_IRUGO, mounts),
2813 REG("mountinfo", S_IRUGO, mountinfo),
2814 #ifdef CONFIG_PROC_PAGE_MONITOR
2815 REG("clear_refs", S_IWUSR, clear_refs),
2816 REG("smaps", S_IRUGO, smaps),
2817 REG("pagemap", S_IRUSR, pagemap),
2818 #endif
2819 #ifdef CONFIG_SECURITY
2820 DIR("attr", S_IRUGO|S_IXUGO, attr_dir),
2821 #endif
2822 #ifdef CONFIG_KALLSYMS
2823 INF("wchan", S_IRUGO, pid_wchan),
2824 #endif
2825 #ifdef CONFIG_SCHEDSTATS
2826 INF("schedstat", S_IRUGO, pid_schedstat),
2827 #endif
2828 #ifdef CONFIG_LATENCYTOP
2829 REG("latency", S_IRUGO, lstats),
2830 #endif
2831 #ifdef CONFIG_PROC_PID_CPUSET
2832 REG("cpuset", S_IRUGO, cpuset),
2833 #endif
2834 #ifdef CONFIG_CGROUPS
2835 REG("cgroup", S_IRUGO, cgroup),
2836 #endif
2837 INF("oom_score", S_IRUGO, oom_score),
2838 REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust),
2839 #ifdef CONFIG_AUDITSYSCALL
2840 REG("loginuid", S_IWUSR|S_IRUGO, loginuid),
2841 REG("sessionid", S_IRUSR, sessionid),
2842 #endif
2843 #ifdef CONFIG_FAULT_INJECTION
2844 REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject),
2845 #endif
2846 #ifdef CONFIG_TASK_IO_ACCOUNTING
2847 INF("io", S_IRUGO, tid_io_accounting),
2848 #endif
2849 };
2850
2851 static int proc_tid_base_readdir(struct file * filp,
2852 void * dirent, filldir_t filldir)
2853 {
2854 return proc_pident_readdir(filp,dirent,filldir,
2855 tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
2856 }
2857
2858 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2859 return proc_pident_lookup(dir, dentry,
2860 tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
2861 }
2862
2863 static const struct file_operations proc_tid_base_operations = {
2864 .read = generic_read_dir,
2865 .readdir = proc_tid_base_readdir,
2866 };
2867
2868 static const struct inode_operations proc_tid_base_inode_operations = {
2869 .lookup = proc_tid_base_lookup,
2870 .getattr = pid_getattr,
2871 .setattr = proc_setattr,
2872 };
2873
2874 static struct dentry *proc_task_instantiate(struct inode *dir,
2875 struct dentry *dentry, struct task_struct *task, const void *ptr)
2876 {
2877 struct dentry *error = ERR_PTR(-ENOENT);
2878 struct inode *inode;
2879 inode = proc_pid_make_inode(dir->i_sb, task);
2880
2881 if (!inode)
2882 goto out;
2883 inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2884 inode->i_op = &proc_tid_base_inode_operations;
2885 inode->i_fop = &proc_tid_base_operations;
2886 inode->i_flags|=S_IMMUTABLE;
2887
2888 inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
2889 ARRAY_SIZE(tid_base_stuff));
2890
2891 dentry->d_op = &pid_dentry_operations;
2892
2893 d_add(dentry, inode);
2894 /* Close the race of the process dying before we return the dentry */
2895 if (pid_revalidate(dentry, NULL))
2896 error = NULL;
2897 out:
2898 return error;
2899 }
2900
2901 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2902 {
2903 struct dentry *result = ERR_PTR(-ENOENT);
2904 struct task_struct *task;
2905 struct task_struct *leader = get_proc_task(dir);
2906 unsigned tid;
2907 struct pid_namespace *ns;
2908
2909 if (!leader)
2910 goto out_no_task;
2911
2912 tid = name_to_int(dentry);
2913 if (tid == ~0U)
2914 goto out;
2915
2916 ns = dentry->d_sb->s_fs_info;
2917 rcu_read_lock();
2918 task = find_task_by_pid_ns(tid, ns);
2919 if (task)
2920 get_task_struct(task);
2921 rcu_read_unlock();
2922 if (!task)
2923 goto out;
2924 if (!same_thread_group(leader, task))
2925 goto out_drop_task;
2926
2927 result = proc_task_instantiate(dir, dentry, task, NULL);
2928 out_drop_task:
2929 put_task_struct(task);
2930 out:
2931 put_task_struct(leader);
2932 out_no_task:
2933 return result;
2934 }
2935
2936 /*
2937 * Find the first tid of a thread group to return to user space.
2938 *
2939 * Usually this is just the thread group leader, but if the users
2940 * buffer was too small or there was a seek into the middle of the
2941 * directory we have more work todo.
2942 *
2943 * In the case of a short read we start with find_task_by_pid.
2944 *
2945 * In the case of a seek we start with the leader and walk nr
2946 * threads past it.
2947 */
2948 static struct task_struct *first_tid(struct task_struct *leader,
2949 int tid, int nr, struct pid_namespace *ns)
2950 {
2951 struct task_struct *pos;
2952
2953 rcu_read_lock();
2954 /* Attempt to start with the pid of a thread */
2955 if (tid && (nr > 0)) {
2956 pos = find_task_by_pid_ns(tid, ns);
2957 if (pos && (pos->group_leader == leader))
2958 goto found;
2959 }
2960
2961 /* If nr exceeds the number of threads there is nothing todo */
2962 pos = NULL;
2963 if (nr && nr >= get_nr_threads(leader))
2964 goto out;
2965
2966 /* If we haven't found our starting place yet start
2967 * with the leader and walk nr threads forward.
2968 */
2969 for (pos = leader; nr > 0; --nr) {
2970 pos = next_thread(pos);
2971 if (pos == leader) {
2972 pos = NULL;
2973 goto out;
2974 }
2975 }
2976 found:
2977 get_task_struct(pos);
2978 out:
2979 rcu_read_unlock();
2980 return pos;
2981 }
2982
2983 /*
2984 * Find the next thread in the thread list.
2985 * Return NULL if there is an error or no next thread.
2986 *
2987 * The reference to the input task_struct is released.
2988 */
2989 static struct task_struct *next_tid(struct task_struct *start)
2990 {
2991 struct task_struct *pos = NULL;
2992 rcu_read_lock();
2993 if (pid_alive(start)) {
2994 pos = next_thread(start);
2995 if (thread_group_leader(pos))
2996 pos = NULL;
2997 else
2998 get_task_struct(pos);
2999 }
3000 rcu_read_unlock();
3001 put_task_struct(start);
3002 return pos;
3003 }
3004
3005 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3006 struct task_struct *task, int tid)
3007 {
3008 char name[PROC_NUMBUF];
3009 int len = snprintf(name, sizeof(name), "%d", tid);
3010 return proc_fill_cache(filp, dirent, filldir, name, len,
3011 proc_task_instantiate, task, NULL);
3012 }
3013
3014 /* for the /proc/TGID/task/ directories */
3015 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3016 {
3017 struct dentry *dentry = filp->f_path.dentry;
3018 struct inode *inode = dentry->d_inode;
3019 struct task_struct *leader = NULL;
3020 struct task_struct *task;
3021 int retval = -ENOENT;
3022 ino_t ino;
3023 int tid;
3024 unsigned long pos = filp->f_pos; /* avoiding "long long" filp->f_pos */
3025 struct pid_namespace *ns;
3026
3027 task = get_proc_task(inode);
3028 if (!task)
3029 goto out_no_task;
3030 rcu_read_lock();
3031 if (pid_alive(task)) {
3032 leader = task->group_leader;
3033 get_task_struct(leader);
3034 }
3035 rcu_read_unlock();
3036 put_task_struct(task);
3037 if (!leader)
3038 goto out_no_task;
3039 retval = 0;
3040
3041 switch (pos) {
3042 case 0:
3043 ino = inode->i_ino;
3044 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
3045 goto out;
3046 pos++;
3047 /* fall through */
3048 case 1:
3049 ino = parent_ino(dentry);
3050 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
3051 goto out;
3052 pos++;
3053 /* fall through */
3054 }
3055
3056 /* f_version caches the tgid value that the last readdir call couldn't
3057 * return. lseek aka telldir automagically resets f_version to 0.
3058 */
3059 ns = filp->f_dentry->d_sb->s_fs_info;
3060 tid = (int)filp->f_version;
3061 filp->f_version = 0;
3062 for (task = first_tid(leader, tid, pos - 2, ns);
3063 task;
3064 task = next_tid(task), pos++) {
3065 tid = task_pid_nr_ns(task, ns);
3066 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3067 /* returning this tgid failed, save it as the first
3068 * pid for the next readir call */
3069 filp->f_version = (u64)tid;
3070 put_task_struct(task);
3071 break;
3072 }
3073 }
3074 out:
3075 filp->f_pos = pos;
3076 put_task_struct(leader);
3077 out_no_task:
3078 return retval;
3079 }
3080
3081 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3082 {
3083 struct inode *inode = dentry->d_inode;
3084 struct task_struct *p = get_proc_task(inode);
3085 generic_fillattr(inode, stat);
3086
3087 if (p) {
3088 rcu_read_lock();
3089 stat->nlink += get_nr_threads(p);
3090 rcu_read_unlock();
3091 put_task_struct(p);
3092 }
3093
3094 return 0;
3095 }
3096
3097 static const struct inode_operations proc_task_inode_operations = {
3098 .lookup = proc_task_lookup,
3099 .getattr = proc_task_getattr,
3100 .setattr = proc_setattr,
3101 };
3102
3103 static const struct file_operations proc_task_operations = {
3104 .read = generic_read_dir,
3105 .readdir = proc_task_readdir,
3106 };
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