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mm: introduce get_user_pages_fast
[linux/fpc-iii.git] / fs / proc / base.c
bloba891fe4cb43bf34e0becd16e642adfc137c0d4e3
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/init.h>
57 #include <linux/capability.h>
58 #include <linux/file.h>
59 #include <linux/fdtable.h>
60 #include <linux/string.h>
61 #include <linux/seq_file.h>
62 #include <linux/namei.h>
63 #include <linux/mnt_namespace.h>
64 #include <linux/mm.h>
65 #include <linux/rcupdate.h>
66 #include <linux/kallsyms.h>
67 #include <linux/resource.h>
68 #include <linux/module.h>
69 #include <linux/mount.h>
70 #include <linux/security.h>
71 #include <linux/ptrace.h>
72 #include <linux/cgroup.h>
73 #include <linux/cpuset.h>
74 #include <linux/audit.h>
75 #include <linux/poll.h>
76 #include <linux/nsproxy.h>
77 #include <linux/oom.h>
78 #include <linux/elf.h>
79 #include <linux/pid_namespace.h>
80 #include "internal.h"
81
82 /* NOTE:
83 * Implementing inode permission operations in /proc is almost
84 * certainly an error. Permission checks need to happen during
85 * each system call not at open time. The reason is that most of
86 * what we wish to check for permissions in /proc varies at runtime.
87 *
88 * The classic example of a problem is opening file descriptors
89 * in /proc for a task before it execs a suid executable.
90 */
91
92 struct pid_entry {
93 char *name;
94 int len;
95 mode_t mode;
96 const struct inode_operations *iop;
97 const struct file_operations *fop;
98 union proc_op op;
99 };
100
101 #define NOD(NAME, MODE, IOP, FOP, OP) { \
102 .name = (NAME), \
103 .len = sizeof(NAME) - 1, \
104 .mode = MODE, \
105 .iop = IOP, \
106 .fop = FOP, \
107 .op = OP, \
108 }
109
110 #define DIR(NAME, MODE, OTYPE) \
111 NOD(NAME, (S_IFDIR|(MODE)), \
112 &proc_##OTYPE##_inode_operations, &proc_##OTYPE##_operations, \
113 {} )
114 #define LNK(NAME, OTYPE) \
115 NOD(NAME, (S_IFLNK|S_IRWXUGO), \
116 &proc_pid_link_inode_operations, NULL, \
117 { .proc_get_link = &proc_##OTYPE##_link } )
118 #define REG(NAME, MODE, OTYPE) \
119 NOD(NAME, (S_IFREG|(MODE)), NULL, \
120 &proc_##OTYPE##_operations, {})
121 #define INF(NAME, MODE, OTYPE) \
122 NOD(NAME, (S_IFREG|(MODE)), \
123 NULL, &proc_info_file_operations, \
124 { .proc_read = &proc_##OTYPE } )
125 #define ONE(NAME, MODE, OTYPE) \
126 NOD(NAME, (S_IFREG|(MODE)), \
127 NULL, &proc_single_file_operations, \
128 { .proc_show = &proc_##OTYPE } )
129
130 /*
131 * Count the number of hardlinks for the pid_entry table, excluding the .
132 * and .. links.
133 */
134 static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
135 unsigned int n)
136 {
137 unsigned int i;
138 unsigned int count;
139
140 count = 0;
141 for (i = 0; i < n; ++i) {
142 if (S_ISDIR(entries[i].mode))
143 ++count;
144 }
145
146 return count;
147 }
148
149 int maps_protect;
150 EXPORT_SYMBOL(maps_protect);
151
152 static struct fs_struct *get_fs_struct(struct task_struct *task)
153 {
154 struct fs_struct *fs;
155 task_lock(task);
156 fs = task->fs;
157 if(fs)
158 atomic_inc(&fs->count);
159 task_unlock(task);
160 return fs;
161 }
162
163 static int get_nr_threads(struct task_struct *tsk)
164 {
165 /* Must be called with the rcu_read_lock held */
166 unsigned long flags;
167 int count = 0;
168
169 if (lock_task_sighand(tsk, &flags)) {
170 count = atomic_read(&tsk->signal->count);
171 unlock_task_sighand(tsk, &flags);
172 }
173 return count;
174 }
175
176 static int proc_cwd_link(struct inode *inode, struct path *path)
177 {
178 struct task_struct *task = get_proc_task(inode);
179 struct fs_struct *fs = NULL;
180 int result = -ENOENT;
181
182 if (task) {
183 fs = get_fs_struct(task);
184 put_task_struct(task);
185 }
186 if (fs) {
187 read_lock(&fs->lock);
188 *path = fs->pwd;
189 path_get(&fs->pwd);
190 read_unlock(&fs->lock);
191 result = 0;
192 put_fs_struct(fs);
193 }
194 return result;
195 }
196
197 static int proc_root_link(struct inode *inode, struct path *path)
198 {
199 struct task_struct *task = get_proc_task(inode);
200 struct fs_struct *fs = NULL;
201 int result = -ENOENT;
202
203 if (task) {
204 fs = get_fs_struct(task);
205 put_task_struct(task);
206 }
207 if (fs) {
208 read_lock(&fs->lock);
209 *path = fs->root;
210 path_get(&fs->root);
211 read_unlock(&fs->lock);
212 result = 0;
213 put_fs_struct(fs);
214 }
215 return result;
216 }
217
218 /*
219 * Return zero if current may access user memory in @task, -error if not.
220 */
221 static int check_mem_permission(struct task_struct *task)
222 {
223 /*
224 * A task can always look at itself, in case it chooses
225 * to use system calls instead of load instructions.
226 */
227 if (task == current)
228 return 0;
229
230 /*
231 * If current is actively ptrace'ing, and would also be
232 * permitted to freshly attach with ptrace now, permit it.
233 */
234 if (task->parent == current && (task->ptrace & PT_PTRACED) &&
235 task_is_stopped_or_traced(task) &&
236 ptrace_may_access(task, PTRACE_MODE_ATTACH))
237 return 0;
238
239 /*
240 * Noone else is allowed.
241 */
242 return -EPERM;
243 }
244
245 struct mm_struct *mm_for_maps(struct task_struct *task)
246 {
247 struct mm_struct *mm = get_task_mm(task);
248 if (!mm)
249 return NULL;
250 down_read(&mm->mmap_sem);
251 task_lock(task);
252 if (task->mm != mm)
253 goto out;
254 if (task->mm != current->mm &&
255 __ptrace_may_access(task, PTRACE_MODE_READ) < 0)
256 goto out;
257 task_unlock(task);
258 return mm;
259 out:
260 task_unlock(task);
261 up_read(&mm->mmap_sem);
262 mmput(mm);
263 return NULL;
264 }
265
266 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
267 {
268 int res = 0;
269 unsigned int len;
270 struct mm_struct *mm = get_task_mm(task);
271 if (!mm)
272 goto out;
273 if (!mm->arg_end)
274 goto out_mm; /* Shh! No looking before we're done */
275
276 len = mm->arg_end - mm->arg_start;
277
278 if (len > PAGE_SIZE)
279 len = PAGE_SIZE;
280
281 res = access_process_vm(task, mm->arg_start, buffer, len, 0);
282
283 // If the nul at the end of args has been overwritten, then
284 // assume application is using setproctitle(3).
285 if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
286 len = strnlen(buffer, res);
287 if (len < res) {
288 res = len;
289 } else {
290 len = mm->env_end - mm->env_start;
291 if (len > PAGE_SIZE - res)
292 len = PAGE_SIZE - res;
293 res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
294 res = strnlen(buffer, res);
295 }
296 }
297 out_mm:
298 mmput(mm);
299 out:
300 return res;
301 }
302
303 static int proc_pid_auxv(struct task_struct *task, char *buffer)
304 {
305 int res = 0;
306 struct mm_struct *mm = get_task_mm(task);
307 if (mm) {
308 unsigned int nwords = 0;
309 do
310 nwords += 2;
311 while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
312 res = nwords * sizeof(mm->saved_auxv[0]);
313 if (res > PAGE_SIZE)
314 res = PAGE_SIZE;
315 memcpy(buffer, mm->saved_auxv, res);
316 mmput(mm);
317 }
318 return res;
319 }
320
321
322 #ifdef CONFIG_KALLSYMS
323 /*
324 * Provides a wchan file via kallsyms in a proper one-value-per-file format.
325 * Returns the resolved symbol. If that fails, simply return the address.
326 */
327 static int proc_pid_wchan(struct task_struct *task, char *buffer)
328 {
329 unsigned long wchan;
330 char symname[KSYM_NAME_LEN];
331
332 wchan = get_wchan(task);
333
334 if (lookup_symbol_name(wchan, symname) < 0)
335 return sprintf(buffer, "%lu", wchan);
336 else
337 return sprintf(buffer, "%s", symname);
338 }
339 #endif /* CONFIG_KALLSYMS */
340
341 #ifdef CONFIG_SCHEDSTATS
342 /*
343 * Provides /proc/PID/schedstat
344 */
345 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
346 {
347 return sprintf(buffer, "%llu %llu %lu\n",
348 task->sched_info.cpu_time,
349 task->sched_info.run_delay,
350 task->sched_info.pcount);
351 }
352 #endif
353
354 #ifdef CONFIG_LATENCYTOP
355 static int lstats_show_proc(struct seq_file *m, void *v)
356 {
357 int i;
358 struct inode *inode = m->private;
359 struct task_struct *task = get_proc_task(inode);
360
361 if (!task)
362 return -ESRCH;
363 seq_puts(m, "Latency Top version : v0.1\n");
364 for (i = 0; i < 32; i++) {
365 if (task->latency_record[i].backtrace[0]) {
366 int q;
367 seq_printf(m, "%i %li %li ",
368 task->latency_record[i].count,
369 task->latency_record[i].time,
370 task->latency_record[i].max);
371 for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
372 char sym[KSYM_NAME_LEN];
373 char *c;
374 if (!task->latency_record[i].backtrace[q])
375 break;
376 if (task->latency_record[i].backtrace[q] == ULONG_MAX)
377 break;
378 sprint_symbol(sym, task->latency_record[i].backtrace[q]);
379 c = strchr(sym, '+');
380 if (c)
381 *c = 0;
382 seq_printf(m, "%s ", sym);
383 }
384 seq_printf(m, "\n");
385 }
386
387 }
388 put_task_struct(task);
389 return 0;
390 }
391
392 static int lstats_open(struct inode *inode, struct file *file)
393 {
394 return single_open(file, lstats_show_proc, inode);
395 }
396
397 static ssize_t lstats_write(struct file *file, const char __user *buf,
398 size_t count, loff_t *offs)
399 {
400 struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
401
402 if (!task)
403 return -ESRCH;
404 clear_all_latency_tracing(task);
405 put_task_struct(task);
406
407 return count;
408 }
409
410 static const struct file_operations proc_lstats_operations = {
411 .open = lstats_open,
412 .read = seq_read,
413 .write = lstats_write,
414 .llseek = seq_lseek,
415 .release = single_release,
416 };
417
418 #endif
419
420 /* The badness from the OOM killer */
421 unsigned long badness(struct task_struct *p, unsigned long uptime);
422 static int proc_oom_score(struct task_struct *task, char *buffer)
423 {
424 unsigned long points;
425 struct timespec uptime;
426
427 do_posix_clock_monotonic_gettime(&uptime);
428 read_lock(&tasklist_lock);
429 points = badness(task, uptime.tv_sec);
430 read_unlock(&tasklist_lock);
431 return sprintf(buffer, "%lu\n", points);
432 }
433
434 struct limit_names {
435 char *name;
436 char *unit;
437 };
438
439 static const struct limit_names lnames[RLIM_NLIMITS] = {
440 [RLIMIT_CPU] = {"Max cpu time", "ms"},
441 [RLIMIT_FSIZE] = {"Max file size", "bytes"},
442 [RLIMIT_DATA] = {"Max data size", "bytes"},
443 [RLIMIT_STACK] = {"Max stack size", "bytes"},
444 [RLIMIT_CORE] = {"Max core file size", "bytes"},
445 [RLIMIT_RSS] = {"Max resident set", "bytes"},
446 [RLIMIT_NPROC] = {"Max processes", "processes"},
447 [RLIMIT_NOFILE] = {"Max open files", "files"},
448 [RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
449 [RLIMIT_AS] = {"Max address space", "bytes"},
450 [RLIMIT_LOCKS] = {"Max file locks", "locks"},
451 [RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
452 [RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
453 [RLIMIT_NICE] = {"Max nice priority", NULL},
454 [RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
455 [RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
456 };
457
458 /* Display limits for a process */
459 static int proc_pid_limits(struct task_struct *task, char *buffer)
460 {
461 unsigned int i;
462 int count = 0;
463 unsigned long flags;
464 char *bufptr = buffer;
465
466 struct rlimit rlim[RLIM_NLIMITS];
467
468 rcu_read_lock();
469 if (!lock_task_sighand(task,&flags)) {
470 rcu_read_unlock();
471 return 0;
472 }
473 memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
474 unlock_task_sighand(task, &flags);
475 rcu_read_unlock();
476
477 /*
478 * print the file header
479 */
480 count += sprintf(&bufptr[count], "%-25s %-20s %-20s %-10s\n",
481 "Limit", "Soft Limit", "Hard Limit", "Units");
482
483 for (i = 0; i < RLIM_NLIMITS; i++) {
484 if (rlim[i].rlim_cur == RLIM_INFINITY)
485 count += sprintf(&bufptr[count], "%-25s %-20s ",
486 lnames[i].name, "unlimited");
487 else
488 count += sprintf(&bufptr[count], "%-25s %-20lu ",
489 lnames[i].name, rlim[i].rlim_cur);
490
491 if (rlim[i].rlim_max == RLIM_INFINITY)
492 count += sprintf(&bufptr[count], "%-20s ", "unlimited");
493 else
494 count += sprintf(&bufptr[count], "%-20lu ",
495 rlim[i].rlim_max);
496
497 if (lnames[i].unit)
498 count += sprintf(&bufptr[count], "%-10s\n",
499 lnames[i].unit);
500 else
501 count += sprintf(&bufptr[count], "\n");
502 }
503
504 return count;
505 }
506
507 /************************************************************************/
508 /* Here the fs part begins */
509 /************************************************************************/
510
511 /* permission checks */
512 static int proc_fd_access_allowed(struct inode *inode)
513 {
514 struct task_struct *task;
515 int allowed = 0;
516 /* Allow access to a task's file descriptors if it is us or we
517 * may use ptrace attach to the process and find out that
518 * information.
519 */
520 task = get_proc_task(inode);
521 if (task) {
522 allowed = ptrace_may_access(task, PTRACE_MODE_READ);
523 put_task_struct(task);
524 }
525 return allowed;
526 }
527
528 static int proc_setattr(struct dentry *dentry, struct iattr *attr)
529 {
530 int error;
531 struct inode *inode = dentry->d_inode;
532
533 if (attr->ia_valid & ATTR_MODE)
534 return -EPERM;
535
536 error = inode_change_ok(inode, attr);
537 if (!error)
538 error = inode_setattr(inode, attr);
539 return error;
540 }
541
542 static const struct inode_operations proc_def_inode_operations = {
543 .setattr = proc_setattr,
544 };
545
546 static int mounts_open_common(struct inode *inode, struct file *file,
547 const struct seq_operations *op)
548 {
549 struct task_struct *task = get_proc_task(inode);
550 struct nsproxy *nsp;
551 struct mnt_namespace *ns = NULL;
552 struct fs_struct *fs = NULL;
553 struct path root;
554 struct proc_mounts *p;
555 int ret = -EINVAL;
556
557 if (task) {
558 rcu_read_lock();
559 nsp = task_nsproxy(task);
560 if (nsp) {
561 ns = nsp->mnt_ns;
562 if (ns)
563 get_mnt_ns(ns);
564 }
565 rcu_read_unlock();
566 if (ns)
567 fs = get_fs_struct(task);
568 put_task_struct(task);
569 }
570
571 if (!ns)
572 goto err;
573 if (!fs)
574 goto err_put_ns;
575
576 read_lock(&fs->lock);
577 root = fs->root;
578 path_get(&root);
579 read_unlock(&fs->lock);
580 put_fs_struct(fs);
581
582 ret = -ENOMEM;
583 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
584 if (!p)
585 goto err_put_path;
586
587 file->private_data = &p->m;
588 ret = seq_open(file, op);
589 if (ret)
590 goto err_free;
591
592 p->m.private = p;
593 p->ns = ns;
594 p->root = root;
595 p->event = ns->event;
596
597 return 0;
598
599 err_free:
600 kfree(p);
601 err_put_path:
602 path_put(&root);
603 err_put_ns:
604 put_mnt_ns(ns);
605 err:
606 return ret;
607 }
608
609 static int mounts_release(struct inode *inode, struct file *file)
610 {
611 struct proc_mounts *p = file->private_data;
612 path_put(&p->root);
613 put_mnt_ns(p->ns);
614 return seq_release(inode, file);
615 }
616
617 static unsigned mounts_poll(struct file *file, poll_table *wait)
618 {
619 struct proc_mounts *p = file->private_data;
620 struct mnt_namespace *ns = p->ns;
621 unsigned res = 0;
622
623 poll_wait(file, &ns->poll, wait);
624
625 spin_lock(&vfsmount_lock);
626 if (p->event != ns->event) {
627 p->event = ns->event;
628 res = POLLERR;
629 }
630 spin_unlock(&vfsmount_lock);
631
632 return res;
633 }
634
635 static int mounts_open(struct inode *inode, struct file *file)
636 {
637 return mounts_open_common(inode, file, &mounts_op);
638 }
639
640 static const struct file_operations proc_mounts_operations = {
641 .open = mounts_open,
642 .read = seq_read,
643 .llseek = seq_lseek,
644 .release = mounts_release,
645 .poll = mounts_poll,
646 };
647
648 static int mountinfo_open(struct inode *inode, struct file *file)
649 {
650 return mounts_open_common(inode, file, &mountinfo_op);
651 }
652
653 static const struct file_operations proc_mountinfo_operations = {
654 .open = mountinfo_open,
655 .read = seq_read,
656 .llseek = seq_lseek,
657 .release = mounts_release,
658 .poll = mounts_poll,
659 };
660
661 static int mountstats_open(struct inode *inode, struct file *file)
662 {
663 return mounts_open_common(inode, file, &mountstats_op);
664 }
665
666 static const struct file_operations proc_mountstats_operations = {
667 .open = mountstats_open,
668 .read = seq_read,
669 .llseek = seq_lseek,
670 .release = mounts_release,
671 };
672
673 #define PROC_BLOCK_SIZE (3*1024) /* 4K page size but our output routines use some slack for overruns */
674
675 static ssize_t proc_info_read(struct file * file, char __user * buf,
676 size_t count, loff_t *ppos)
677 {
678 struct inode * inode = file->f_path.dentry->d_inode;
679 unsigned long page;
680 ssize_t length;
681 struct task_struct *task = get_proc_task(inode);
682
683 length = -ESRCH;
684 if (!task)
685 goto out_no_task;
686
687 if (count > PROC_BLOCK_SIZE)
688 count = PROC_BLOCK_SIZE;
689
690 length = -ENOMEM;
691 if (!(page = __get_free_page(GFP_TEMPORARY)))
692 goto out;
693
694 length = PROC_I(inode)->op.proc_read(task, (char*)page);
695
696 if (length >= 0)
697 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
698 free_page(page);
699 out:
700 put_task_struct(task);
701 out_no_task:
702 return length;
703 }
704
705 static const struct file_operations proc_info_file_operations = {
706 .read = proc_info_read,
707 };
708
709 static int proc_single_show(struct seq_file *m, void *v)
710 {
711 struct inode *inode = m->private;
712 struct pid_namespace *ns;
713 struct pid *pid;
714 struct task_struct *task;
715 int ret;
716
717 ns = inode->i_sb->s_fs_info;
718 pid = proc_pid(inode);
719 task = get_pid_task(pid, PIDTYPE_PID);
720 if (!task)
721 return -ESRCH;
722
723 ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
724
725 put_task_struct(task);
726 return ret;
727 }
728
729 static int proc_single_open(struct inode *inode, struct file *filp)
730 {
731 int ret;
732 ret = single_open(filp, proc_single_show, NULL);
733 if (!ret) {
734 struct seq_file *m = filp->private_data;
735
736 m->private = inode;
737 }
738 return ret;
739 }
740
741 static const struct file_operations proc_single_file_operations = {
742 .open = proc_single_open,
743 .read = seq_read,
744 .llseek = seq_lseek,
745 .release = single_release,
746 };
747
748 static int mem_open(struct inode* inode, struct file* file)
749 {
750 file->private_data = (void*)((long)current->self_exec_id);
751 return 0;
752 }
753
754 static ssize_t mem_read(struct file * file, char __user * buf,
755 size_t count, loff_t *ppos)
756 {
757 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
758 char *page;
759 unsigned long src = *ppos;
760 int ret = -ESRCH;
761 struct mm_struct *mm;
762
763 if (!task)
764 goto out_no_task;
765
766 if (check_mem_permission(task))
767 goto out;
768
769 ret = -ENOMEM;
770 page = (char *)__get_free_page(GFP_TEMPORARY);
771 if (!page)
772 goto out;
773
774 ret = 0;
775
776 mm = get_task_mm(task);
777 if (!mm)
778 goto out_free;
779
780 ret = -EIO;
781
782 if (file->private_data != (void*)((long)current->self_exec_id))
783 goto out_put;
784
785 ret = 0;
786
787 while (count > 0) {
788 int this_len, retval;
789
790 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
791 retval = access_process_vm(task, src, page, this_len, 0);
792 if (!retval || check_mem_permission(task)) {
793 if (!ret)
794 ret = -EIO;
795 break;
796 }
797
798 if (copy_to_user(buf, page, retval)) {
799 ret = -EFAULT;
800 break;
801 }
802
803 ret += retval;
804 src += retval;
805 buf += retval;
806 count -= retval;
807 }
808 *ppos = src;
809
810 out_put:
811 mmput(mm);
812 out_free:
813 free_page((unsigned long) page);
814 out:
815 put_task_struct(task);
816 out_no_task:
817 return ret;
818 }
819
820 #define mem_write NULL
821
822 #ifndef mem_write
823 /* This is a security hazard */
824 static ssize_t mem_write(struct file * file, const char __user *buf,
825 size_t count, loff_t *ppos)
826 {
827 int copied;
828 char *page;
829 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
830 unsigned long dst = *ppos;
831
832 copied = -ESRCH;
833 if (!task)
834 goto out_no_task;
835
836 if (check_mem_permission(task))
837 goto out;
838
839 copied = -ENOMEM;
840 page = (char *)__get_free_page(GFP_TEMPORARY);
841 if (!page)
842 goto out;
843
844 copied = 0;
845 while (count > 0) {
846 int this_len, retval;
847
848 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
849 if (copy_from_user(page, buf, this_len)) {
850 copied = -EFAULT;
851 break;
852 }
853 retval = access_process_vm(task, dst, page, this_len, 1);
854 if (!retval) {
855 if (!copied)
856 copied = -EIO;
857 break;
858 }
859 copied += retval;
860 buf += retval;
861 dst += retval;
862 count -= retval;
863 }
864 *ppos = dst;
865 free_page((unsigned long) page);
866 out:
867 put_task_struct(task);
868 out_no_task:
869 return copied;
870 }
871 #endif
872
873 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
874 {
875 switch (orig) {
876 case 0:
877 file->f_pos = offset;
878 break;
879 case 1:
880 file->f_pos += offset;
881 break;
882 default:
883 return -EINVAL;
884 }
885 force_successful_syscall_return();
886 return file->f_pos;
887 }
888
889 static const struct file_operations proc_mem_operations = {
890 .llseek = mem_lseek,
891 .read = mem_read,
892 .write = mem_write,
893 .open = mem_open,
894 };
895
896 static ssize_t environ_read(struct file *file, char __user *buf,
897 size_t count, loff_t *ppos)
898 {
899 struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
900 char *page;
901 unsigned long src = *ppos;
902 int ret = -ESRCH;
903 struct mm_struct *mm;
904
905 if (!task)
906 goto out_no_task;
907
908 if (!ptrace_may_access(task, PTRACE_MODE_READ))
909 goto out;
910
911 ret = -ENOMEM;
912 page = (char *)__get_free_page(GFP_TEMPORARY);
913 if (!page)
914 goto out;
915
916 ret = 0;
917
918 mm = get_task_mm(task);
919 if (!mm)
920 goto out_free;
921
922 while (count > 0) {
923 int this_len, retval, max_len;
924
925 this_len = mm->env_end - (mm->env_start + src);
926
927 if (this_len <= 0)
928 break;
929
930 max_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
931 this_len = (this_len > max_len) ? max_len : this_len;
932
933 retval = access_process_vm(task, (mm->env_start + src),
934 page, this_len, 0);
935
936 if (retval <= 0) {
937 ret = retval;
938 break;
939 }
940
941 if (copy_to_user(buf, page, retval)) {
942 ret = -EFAULT;
943 break;
944 }
945
946 ret += retval;
947 src += retval;
948 buf += retval;
949 count -= retval;
950 }
951 *ppos = src;
952
953 mmput(mm);
954 out_free:
955 free_page((unsigned long) page);
956 out:
957 put_task_struct(task);
958 out_no_task:
959 return ret;
960 }
961
962 static const struct file_operations proc_environ_operations = {
963 .read = environ_read,
964 };
965
966 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
967 size_t count, loff_t *ppos)
968 {
969 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
970 char buffer[PROC_NUMBUF];
971 size_t len;
972 int oom_adjust;
973
974 if (!task)
975 return -ESRCH;
976 oom_adjust = task->oomkilladj;
977 put_task_struct(task);
978
979 len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);
980
981 return simple_read_from_buffer(buf, count, ppos, buffer, len);
982 }
983
984 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
985 size_t count, loff_t *ppos)
986 {
987 struct task_struct *task;
988 char buffer[PROC_NUMBUF], *end;
989 int oom_adjust;
990
991 memset(buffer, 0, sizeof(buffer));
992 if (count > sizeof(buffer) - 1)
993 count = sizeof(buffer) - 1;
994 if (copy_from_user(buffer, buf, count))
995 return -EFAULT;
996 oom_adjust = simple_strtol(buffer, &end, 0);
997 if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
998 oom_adjust != OOM_DISABLE)
999 return -EINVAL;
1000 if (*end == '\n')
1001 end++;
1002 task = get_proc_task(file->f_path.dentry->d_inode);
1003 if (!task)
1004 return -ESRCH;
1005 if (oom_adjust < task->oomkilladj && !capable(CAP_SYS_RESOURCE)) {
1006 put_task_struct(task);
1007 return -EACCES;
1008 }
1009 task->oomkilladj = oom_adjust;
1010 put_task_struct(task);
1011 if (end - buffer == 0)
1012 return -EIO;
1013 return end - buffer;
1014 }
1015
1016 static const struct file_operations proc_oom_adjust_operations = {
1017 .read = oom_adjust_read,
1018 .write = oom_adjust_write,
1019 };
1020
1021 #ifdef CONFIG_AUDITSYSCALL
1022 #define TMPBUFLEN 21
1023 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
1024 size_t count, loff_t *ppos)
1025 {
1026 struct inode * inode = file->f_path.dentry->d_inode;
1027 struct task_struct *task = get_proc_task(inode);
1028 ssize_t length;
1029 char tmpbuf[TMPBUFLEN];
1030
1031 if (!task)
1032 return -ESRCH;
1033 length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1034 audit_get_loginuid(task));
1035 put_task_struct(task);
1036 return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1037 }
1038
1039 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1040 size_t count, loff_t *ppos)
1041 {
1042 struct inode * inode = file->f_path.dentry->d_inode;
1043 char *page, *tmp;
1044 ssize_t length;
1045 uid_t loginuid;
1046
1047 if (!capable(CAP_AUDIT_CONTROL))
1048 return -EPERM;
1049
1050 if (current != pid_task(proc_pid(inode), PIDTYPE_PID))
1051 return -EPERM;
1052
1053 if (count >= PAGE_SIZE)
1054 count = PAGE_SIZE - 1;
1055
1056 if (*ppos != 0) {
1057 /* No partial writes. */
1058 return -EINVAL;
1059 }
1060 page = (char*)__get_free_page(GFP_TEMPORARY);
1061 if (!page)
1062 return -ENOMEM;
1063 length = -EFAULT;
1064 if (copy_from_user(page, buf, count))
1065 goto out_free_page;
1066
1067 page[count] = '\0';
1068 loginuid = simple_strtoul(page, &tmp, 10);
1069 if (tmp == page) {
1070 length = -EINVAL;
1071 goto out_free_page;
1072
1073 }
1074 length = audit_set_loginuid(current, loginuid);
1075 if (likely(length == 0))
1076 length = count;
1077
1078 out_free_page:
1079 free_page((unsigned long) page);
1080 return length;
1081 }
1082
1083 static const struct file_operations proc_loginuid_operations = {
1084 .read = proc_loginuid_read,
1085 .write = proc_loginuid_write,
1086 };
1087
1088 static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
1089 size_t count, loff_t *ppos)
1090 {
1091 struct inode * inode = file->f_path.dentry->d_inode;
1092 struct task_struct *task = get_proc_task(inode);
1093 ssize_t length;
1094 char tmpbuf[TMPBUFLEN];
1095
1096 if (!task)
1097 return -ESRCH;
1098 length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1099 audit_get_sessionid(task));
1100 put_task_struct(task);
1101 return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1102 }
1103
1104 static const struct file_operations proc_sessionid_operations = {
1105 .read = proc_sessionid_read,
1106 };
1107 #endif
1108
1109 #ifdef CONFIG_FAULT_INJECTION
1110 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
1111 size_t count, loff_t *ppos)
1112 {
1113 struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
1114 char buffer[PROC_NUMBUF];
1115 size_t len;
1116 int make_it_fail;
1117
1118 if (!task)
1119 return -ESRCH;
1120 make_it_fail = task->make_it_fail;
1121 put_task_struct(task);
1122
1123 len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
1124
1125 return simple_read_from_buffer(buf, count, ppos, buffer, len);
1126 }
1127
1128 static ssize_t proc_fault_inject_write(struct file * file,
1129 const char __user * buf, size_t count, loff_t *ppos)
1130 {
1131 struct task_struct *task;
1132 char buffer[PROC_NUMBUF], *end;
1133 int make_it_fail;
1134
1135 if (!capable(CAP_SYS_RESOURCE))
1136 return -EPERM;
1137 memset(buffer, 0, sizeof(buffer));
1138 if (count > sizeof(buffer) - 1)
1139 count = sizeof(buffer) - 1;
1140 if (copy_from_user(buffer, buf, count))
1141 return -EFAULT;
1142 make_it_fail = simple_strtol(buffer, &end, 0);
1143 if (*end == '\n')
1144 end++;
1145 task = get_proc_task(file->f_dentry->d_inode);
1146 if (!task)
1147 return -ESRCH;
1148 task->make_it_fail = make_it_fail;
1149 put_task_struct(task);
1150 if (end - buffer == 0)
1151 return -EIO;
1152 return end - buffer;
1153 }
1154
1155 static const struct file_operations proc_fault_inject_operations = {
1156 .read = proc_fault_inject_read,
1157 .write = proc_fault_inject_write,
1158 };
1159 #endif
1160
1161
1162 #ifdef CONFIG_SCHED_DEBUG
1163 /*
1164 * Print out various scheduling related per-task fields:
1165 */
1166 static int sched_show(struct seq_file *m, void *v)
1167 {
1168 struct inode *inode = m->private;
1169 struct task_struct *p;
1170
1171 WARN_ON(!inode);
1172
1173 p = get_proc_task(inode);
1174 if (!p)
1175 return -ESRCH;
1176 proc_sched_show_task(p, m);
1177
1178 put_task_struct(p);
1179
1180 return 0;
1181 }
1182
1183 static ssize_t
1184 sched_write(struct file *file, const char __user *buf,
1185 size_t count, loff_t *offset)
1186 {
1187 struct inode *inode = file->f_path.dentry->d_inode;
1188 struct task_struct *p;
1189
1190 WARN_ON(!inode);
1191
1192 p = get_proc_task(inode);
1193 if (!p)
1194 return -ESRCH;
1195 proc_sched_set_task(p);
1196
1197 put_task_struct(p);
1198
1199 return count;
1200 }
1201
1202 static int sched_open(struct inode *inode, struct file *filp)
1203 {
1204 int ret;
1205
1206 ret = single_open(filp, sched_show, NULL);
1207 if (!ret) {
1208 struct seq_file *m = filp->private_data;
1209
1210 m->private = inode;
1211 }
1212 return ret;
1213 }
1214
1215 static const struct file_operations proc_pid_sched_operations = {
1216 .open = sched_open,
1217 .read = seq_read,
1218 .write = sched_write,
1219 .llseek = seq_lseek,
1220 .release = single_release,
1221 };
1222
1223 #endif
1224
1225 /*
1226 * We added or removed a vma mapping the executable. The vmas are only mapped
1227 * during exec and are not mapped with the mmap system call.
1228 * Callers must hold down_write() on the mm's mmap_sem for these
1229 */
1230 void added_exe_file_vma(struct mm_struct *mm)
1231 {
1232 mm->num_exe_file_vmas++;
1233 }
1234
1235 void removed_exe_file_vma(struct mm_struct *mm)
1236 {
1237 mm->num_exe_file_vmas--;
1238 if ((mm->num_exe_file_vmas == 0) && mm->exe_file){
1239 fput(mm->exe_file);
1240 mm->exe_file = NULL;
1241 }
1242
1243 }
1244
1245 void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
1246 {
1247 if (new_exe_file)
1248 get_file(new_exe_file);
1249 if (mm->exe_file)
1250 fput(mm->exe_file);
1251 mm->exe_file = new_exe_file;
1252 mm->num_exe_file_vmas = 0;
1253 }
1254
1255 struct file *get_mm_exe_file(struct mm_struct *mm)
1256 {
1257 struct file *exe_file;
1258
1259 /* We need mmap_sem to protect against races with removal of
1260 * VM_EXECUTABLE vmas */
1261 down_read(&mm->mmap_sem);
1262 exe_file = mm->exe_file;
1263 if (exe_file)
1264 get_file(exe_file);
1265 up_read(&mm->mmap_sem);
1266 return exe_file;
1267 }
1268
1269 void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm)
1270 {
1271 /* It's safe to write the exe_file pointer without exe_file_lock because
1272 * this is called during fork when the task is not yet in /proc */
1273 newmm->exe_file = get_mm_exe_file(oldmm);
1274 }
1275
1276 static int proc_exe_link(struct inode *inode, struct path *exe_path)
1277 {
1278 struct task_struct *task;
1279 struct mm_struct *mm;
1280 struct file *exe_file;
1281
1282 task = get_proc_task(inode);
1283 if (!task)
1284 return -ENOENT;
1285 mm = get_task_mm(task);
1286 put_task_struct(task);
1287 if (!mm)
1288 return -ENOENT;
1289 exe_file = get_mm_exe_file(mm);
1290 mmput(mm);
1291 if (exe_file) {
1292 *exe_path = exe_file->f_path;
1293 path_get(&exe_file->f_path);
1294 fput(exe_file);
1295 return 0;
1296 } else
1297 return -ENOENT;
1298 }
1299
1300 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1301 {
1302 struct inode *inode = dentry->d_inode;
1303 int error = -EACCES;
1304
1305 /* We don't need a base pointer in the /proc filesystem */
1306 path_put(&nd->path);
1307
1308 /* Are we allowed to snoop on the tasks file descriptors? */
1309 if (!proc_fd_access_allowed(inode))
1310 goto out;
1311
1312 error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
1313 nd->last_type = LAST_BIND;
1314 out:
1315 return ERR_PTR(error);
1316 }
1317
1318 static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
1319 {
1320 char *tmp = (char*)__get_free_page(GFP_TEMPORARY);
1321 char *pathname;
1322 int len;
1323
1324 if (!tmp)
1325 return -ENOMEM;
1326
1327 pathname = d_path(path, tmp, PAGE_SIZE);
1328 len = PTR_ERR(pathname);
1329 if (IS_ERR(pathname))
1330 goto out;
1331 len = tmp + PAGE_SIZE - 1 - pathname;
1332
1333 if (len > buflen)
1334 len = buflen;
1335 if (copy_to_user(buffer, pathname, len))
1336 len = -EFAULT;
1337 out:
1338 free_page((unsigned long)tmp);
1339 return len;
1340 }
1341
1342 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1343 {
1344 int error = -EACCES;
1345 struct inode *inode = dentry->d_inode;
1346 struct path path;
1347
1348 /* Are we allowed to snoop on the tasks file descriptors? */
1349 if (!proc_fd_access_allowed(inode))
1350 goto out;
1351
1352 error = PROC_I(inode)->op.proc_get_link(inode, &path);
1353 if (error)
1354 goto out;
1355
1356 error = do_proc_readlink(&path, buffer, buflen);
1357 path_put(&path);
1358 out:
1359 return error;
1360 }
1361
1362 static const struct inode_operations proc_pid_link_inode_operations = {
1363 .readlink = proc_pid_readlink,
1364 .follow_link = proc_pid_follow_link,
1365 .setattr = proc_setattr,
1366 };
1367
1368
1369 /* building an inode */
1370
1371 static int task_dumpable(struct task_struct *task)
1372 {
1373 int dumpable = 0;
1374 struct mm_struct *mm;
1375
1376 task_lock(task);
1377 mm = task->mm;
1378 if (mm)
1379 dumpable = get_dumpable(mm);
1380 task_unlock(task);
1381 if(dumpable == 1)
1382 return 1;
1383 return 0;
1384 }
1385
1386
1387 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
1388 {
1389 struct inode * inode;
1390 struct proc_inode *ei;
1391
1392 /* We need a new inode */
1393
1394 inode = new_inode(sb);
1395 if (!inode)
1396 goto out;
1397
1398 /* Common stuff */
1399 ei = PROC_I(inode);
1400 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1401 inode->i_op = &proc_def_inode_operations;
1402
1403 /*
1404 * grab the reference to task.
1405 */
1406 ei->pid = get_task_pid(task, PIDTYPE_PID);
1407 if (!ei->pid)
1408 goto out_unlock;
1409
1410 inode->i_uid = 0;
1411 inode->i_gid = 0;
1412 if (task_dumpable(task)) {
1413 inode->i_uid = task->euid;
1414 inode->i_gid = task->egid;
1415 }
1416 security_task_to_inode(task, inode);
1417
1418 out:
1419 return inode;
1420
1421 out_unlock:
1422 iput(inode);
1423 return NULL;
1424 }
1425
1426 static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
1427 {
1428 struct inode *inode = dentry->d_inode;
1429 struct task_struct *task;
1430 generic_fillattr(inode, stat);
1431
1432 rcu_read_lock();
1433 stat->uid = 0;
1434 stat->gid = 0;
1435 task = pid_task(proc_pid(inode), PIDTYPE_PID);
1436 if (task) {
1437 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1438 task_dumpable(task)) {
1439 stat->uid = task->euid;
1440 stat->gid = task->egid;
1441 }
1442 }
1443 rcu_read_unlock();
1444 return 0;
1445 }
1446
1447 /* dentry stuff */
1448
1449 /*
1450 * Exceptional case: normally we are not allowed to unhash a busy
1451 * directory. In this case, however, we can do it - no aliasing problems
1452 * due to the way we treat inodes.
1453 *
1454 * Rewrite the inode's ownerships here because the owning task may have
1455 * performed a setuid(), etc.
1456 *
1457 * Before the /proc/pid/status file was created the only way to read
1458 * the effective uid of a /process was to stat /proc/pid. Reading
1459 * /proc/pid/status is slow enough that procps and other packages
1460 * kept stating /proc/pid. To keep the rules in /proc simple I have
1461 * made this apply to all per process world readable and executable
1462 * directories.
1463 */
1464 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1465 {
1466 struct inode *inode = dentry->d_inode;
1467 struct task_struct *task = get_proc_task(inode);
1468 if (task) {
1469 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
1470 task_dumpable(task)) {
1471 inode->i_uid = task->euid;
1472 inode->i_gid = task->egid;
1473 } else {
1474 inode->i_uid = 0;
1475 inode->i_gid = 0;
1476 }
1477 inode->i_mode &= ~(S_ISUID | S_ISGID);
1478 security_task_to_inode(task, inode);
1479 put_task_struct(task);
1480 return 1;
1481 }
1482 d_drop(dentry);
1483 return 0;
1484 }
1485
1486 static int pid_delete_dentry(struct dentry * dentry)
1487 {
1488 /* Is the task we represent dead?
1489 * If so, then don't put the dentry on the lru list,
1490 * kill it immediately.
1491 */
1492 return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
1493 }
1494
1495 static struct dentry_operations pid_dentry_operations =
1496 {
1497 .d_revalidate = pid_revalidate,
1498 .d_delete = pid_delete_dentry,
1499 };
1500
1501 /* Lookups */
1502
1503 typedef struct dentry *instantiate_t(struct inode *, struct dentry *,
1504 struct task_struct *, const void *);
1505
1506 /*
1507 * Fill a directory entry.
1508 *
1509 * If possible create the dcache entry and derive our inode number and
1510 * file type from dcache entry.
1511 *
1512 * Since all of the proc inode numbers are dynamically generated, the inode
1513 * numbers do not exist until the inode is cache. This means creating the
1514 * the dcache entry in readdir is necessary to keep the inode numbers
1515 * reported by readdir in sync with the inode numbers reported
1516 * by stat.
1517 */
1518 static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
1519 char *name, int len,
1520 instantiate_t instantiate, struct task_struct *task, const void *ptr)
1521 {
1522 struct dentry *child, *dir = filp->f_path.dentry;
1523 struct inode *inode;
1524 struct qstr qname;
1525 ino_t ino = 0;
1526 unsigned type = DT_UNKNOWN;
1527
1528 qname.name = name;
1529 qname.len = len;
1530 qname.hash = full_name_hash(name, len);
1531
1532 child = d_lookup(dir, &qname);
1533 if (!child) {
1534 struct dentry *new;
1535 new = d_alloc(dir, &qname);
1536 if (new) {
1537 child = instantiate(dir->d_inode, new, task, ptr);
1538 if (child)
1539 dput(new);
1540 else
1541 child = new;
1542 }
1543 }
1544 if (!child || IS_ERR(child) || !child->d_inode)
1545 goto end_instantiate;
1546 inode = child->d_inode;
1547 if (inode) {
1548 ino = inode->i_ino;
1549 type = inode->i_mode >> 12;
1550 }
1551 dput(child);
1552 end_instantiate:
1553 if (!ino)
1554 ino = find_inode_number(dir, &qname);
1555 if (!ino)
1556 ino = 1;
1557 return filldir(dirent, name, len, filp->f_pos, ino, type);
1558 }
1559
1560 static unsigned name_to_int(struct dentry *dentry)
1561 {
1562 const char *name = dentry->d_name.name;
1563 int len = dentry->d_name.len;
1564 unsigned n = 0;
1565
1566 if (len > 1 && *name == '0')
1567 goto out;
1568 while (len-- > 0) {
1569 unsigned c = *name++ - '0';
1570 if (c > 9)
1571 goto out;
1572 if (n >= (~0U-9)/10)
1573 goto out;
1574 n *= 10;
1575 n += c;
1576 }
1577 return n;
1578 out:
1579 return ~0U;
1580 }
1581
1582 #define PROC_FDINFO_MAX 64
1583
1584 static int proc_fd_info(struct inode *inode, struct path *path, char *info)
1585 {
1586 struct task_struct *task = get_proc_task(inode);
1587 struct files_struct *files = NULL;
1588 struct file *file;
1589 int fd = proc_fd(inode);
1590
1591 if (task) {
1592 files = get_files_struct(task);
1593 put_task_struct(task);
1594 }
1595 if (files) {
1596 /*
1597 * We are not taking a ref to the file structure, so we must
1598 * hold ->file_lock.
1599 */
1600 spin_lock(&files->file_lock);
1601 file = fcheck_files(files, fd);
1602 if (file) {
1603 if (path) {
1604 *path = file->f_path;
1605 path_get(&file->f_path);
1606 }
1607 if (info)
1608 snprintf(info, PROC_FDINFO_MAX,
1609 "pos:\t%lli\n"
1610 "flags:\t0%o\n",
1611 (long long) file->f_pos,
1612 file->f_flags);
1613 spin_unlock(&files->file_lock);
1614 put_files_struct(files);
1615 return 0;
1616 }
1617 spin_unlock(&files->file_lock);
1618 put_files_struct(files);
1619 }
1620 return -ENOENT;
1621 }
1622
1623 static int proc_fd_link(struct inode *inode, struct path *path)
1624 {
1625 return proc_fd_info(inode, path, NULL);
1626 }
1627
1628 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1629 {
1630 struct inode *inode = dentry->d_inode;
1631 struct task_struct *task = get_proc_task(inode);
1632 int fd = proc_fd(inode);
1633 struct files_struct *files;
1634
1635 if (task) {
1636 files = get_files_struct(task);
1637 if (files) {
1638 rcu_read_lock();
1639 if (fcheck_files(files, fd)) {
1640 rcu_read_unlock();
1641 put_files_struct(files);
1642 if (task_dumpable(task)) {
1643 inode->i_uid = task->euid;
1644 inode->i_gid = task->egid;
1645 } else {
1646 inode->i_uid = 0;
1647 inode->i_gid = 0;
1648 }
1649 inode->i_mode &= ~(S_ISUID | S_ISGID);
1650 security_task_to_inode(task, inode);
1651 put_task_struct(task);
1652 return 1;
1653 }
1654 rcu_read_unlock();
1655 put_files_struct(files);
1656 }
1657 put_task_struct(task);
1658 }
1659 d_drop(dentry);
1660 return 0;
1661 }
1662
1663 static struct dentry_operations tid_fd_dentry_operations =
1664 {
1665 .d_revalidate = tid_fd_revalidate,
1666 .d_delete = pid_delete_dentry,
1667 };
1668
1669 static struct dentry *proc_fd_instantiate(struct inode *dir,
1670 struct dentry *dentry, struct task_struct *task, const void *ptr)
1671 {
1672 unsigned fd = *(const unsigned *)ptr;
1673 struct file *file;
1674 struct files_struct *files;
1675 struct inode *inode;
1676 struct proc_inode *ei;
1677 struct dentry *error = ERR_PTR(-ENOENT);
1678
1679 inode = proc_pid_make_inode(dir->i_sb, task);
1680 if (!inode)
1681 goto out;
1682 ei = PROC_I(inode);
1683 ei->fd = fd;
1684 files = get_files_struct(task);
1685 if (!files)
1686 goto out_iput;
1687 inode->i_mode = S_IFLNK;
1688
1689 /*
1690 * We are not taking a ref to the file structure, so we must
1691 * hold ->file_lock.
1692 */
1693 spin_lock(&files->file_lock);
1694 file = fcheck_files(files, fd);
1695 if (!file)
1696 goto out_unlock;
1697 if (file->f_mode & 1)
1698 inode->i_mode |= S_IRUSR | S_IXUSR;
1699 if (file->f_mode & 2)
1700 inode->i_mode |= S_IWUSR | S_IXUSR;
1701 spin_unlock(&files->file_lock);
1702 put_files_struct(files);
1703
1704 inode->i_op = &proc_pid_link_inode_operations;
1705 inode->i_size = 64;
1706 ei->op.proc_get_link = proc_fd_link;
1707 dentry->d_op = &tid_fd_dentry_operations;
1708 d_add(dentry, inode);
1709 /* Close the race of the process dying before we return the dentry */
1710 if (tid_fd_revalidate(dentry, NULL))
1711 error = NULL;
1712
1713 out:
1714 return error;
1715 out_unlock:
1716 spin_unlock(&files->file_lock);
1717 put_files_struct(files);
1718 out_iput:
1719 iput(inode);
1720 goto out;
1721 }
1722
1723 static struct dentry *proc_lookupfd_common(struct inode *dir,
1724 struct dentry *dentry,
1725 instantiate_t instantiate)
1726 {
1727 struct task_struct *task = get_proc_task(dir);
1728 unsigned fd = name_to_int(dentry);
1729 struct dentry *result = ERR_PTR(-ENOENT);
1730
1731 if (!task)
1732 goto out_no_task;
1733 if (fd == ~0U)
1734 goto out;
1735
1736 result = instantiate(dir, dentry, task, &fd);
1737 out:
1738 put_task_struct(task);
1739 out_no_task:
1740 return result;
1741 }
1742
1743 static int proc_readfd_common(struct file * filp, void * dirent,
1744 filldir_t filldir, instantiate_t instantiate)
1745 {
1746 struct dentry *dentry = filp->f_path.dentry;
1747 struct inode *inode = dentry->d_inode;
1748 struct task_struct *p = get_proc_task(inode);
1749 unsigned int fd, ino;
1750 int retval;
1751 struct files_struct * files;
1752
1753 retval = -ENOENT;
1754 if (!p)
1755 goto out_no_task;
1756 retval = 0;
1757
1758 fd = filp->f_pos;
1759 switch (fd) {
1760 case 0:
1761 if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1762 goto out;
1763 filp->f_pos++;
1764 case 1:
1765 ino = parent_ino(dentry);
1766 if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1767 goto out;
1768 filp->f_pos++;
1769 default:
1770 files = get_files_struct(p);
1771 if (!files)
1772 goto out;
1773 rcu_read_lock();
1774 for (fd = filp->f_pos-2;
1775 fd < files_fdtable(files)->max_fds;
1776 fd++, filp->f_pos++) {
1777 char name[PROC_NUMBUF];
1778 int len;
1779
1780 if (!fcheck_files(files, fd))
1781 continue;
1782 rcu_read_unlock();
1783
1784 len = snprintf(name, sizeof(name), "%d", fd);
1785 if (proc_fill_cache(filp, dirent, filldir,
1786 name, len, instantiate,
1787 p, &fd) < 0) {
1788 rcu_read_lock();
1789 break;
1790 }
1791 rcu_read_lock();
1792 }
1793 rcu_read_unlock();
1794 put_files_struct(files);
1795 }
1796 out:
1797 put_task_struct(p);
1798 out_no_task:
1799 return retval;
1800 }
1801
1802 static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
1803 struct nameidata *nd)
1804 {
1805 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
1806 }
1807
1808 static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
1809 {
1810 return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
1811 }
1812
1813 static ssize_t proc_fdinfo_read(struct file *file, char __user *buf,
1814 size_t len, loff_t *ppos)
1815 {
1816 char tmp[PROC_FDINFO_MAX];
1817 int err = proc_fd_info(file->f_path.dentry->d_inode, NULL, tmp);
1818 if (!err)
1819 err = simple_read_from_buffer(buf, len, ppos, tmp, strlen(tmp));
1820 return err;
1821 }
1822
1823 static const struct file_operations proc_fdinfo_file_operations = {
1824 .open = nonseekable_open,
1825 .read = proc_fdinfo_read,
1826 };
1827
1828 static const struct file_operations proc_fd_operations = {
1829 .read = generic_read_dir,
1830 .readdir = proc_readfd,
1831 };
1832
1833 /*
1834 * /proc/pid/fd needs a special permission handler so that a process can still
1835 * access /proc/self/fd after it has executed a setuid().
1836 */
1837 static int proc_fd_permission(struct inode *inode, int mask,
1838 struct nameidata *nd)
1839 {
1840 int rv;
1841
1842 rv = generic_permission(inode, mask, NULL);
1843 if (rv == 0)
1844 return 0;
1845 if (task_pid(current) == proc_pid(inode))
1846 rv = 0;
1847 return rv;
1848 }
1849
1850 /*
1851 * proc directories can do almost nothing..
1852 */
1853 static const struct inode_operations proc_fd_inode_operations = {
1854 .lookup = proc_lookupfd,
1855 .permission = proc_fd_permission,
1856 .setattr = proc_setattr,
1857 };
1858
1859 static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
1860 struct dentry *dentry, struct task_struct *task, const void *ptr)
1861 {
1862 unsigned fd = *(unsigned *)ptr;
1863 struct inode *inode;
1864 struct proc_inode *ei;
1865 struct dentry *error = ERR_PTR(-ENOENT);
1866
1867 inode = proc_pid_make_inode(dir->i_sb, task);
1868 if (!inode)
1869 goto out;
1870 ei = PROC_I(inode);
1871 ei->fd = fd;
1872 inode->i_mode = S_IFREG | S_IRUSR;
1873 inode->i_fop = &proc_fdinfo_file_operations;
1874 dentry->d_op = &tid_fd_dentry_operations;
1875 d_add(dentry, inode);
1876 /* Close the race of the process dying before we return the dentry */
1877 if (tid_fd_revalidate(dentry, NULL))
1878 error = NULL;
1879
1880 out:
1881 return error;
1882 }
1883
1884 static struct dentry *proc_lookupfdinfo(struct inode *dir,
1885 struct dentry *dentry,
1886 struct nameidata *nd)
1887 {
1888 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
1889 }
1890
1891 static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
1892 {
1893 return proc_readfd_common(filp, dirent, filldir,
1894 proc_fdinfo_instantiate);
1895 }
1896
1897 static const struct file_operations proc_fdinfo_operations = {
1898 .read = generic_read_dir,
1899 .readdir = proc_readfdinfo,
1900 };
1901
1902 /*
1903 * proc directories can do almost nothing..
1904 */
1905 static const struct inode_operations proc_fdinfo_inode_operations = {
1906 .lookup = proc_lookupfdinfo,
1907 .setattr = proc_setattr,
1908 };
1909
1910
1911 static struct dentry *proc_pident_instantiate(struct inode *dir,
1912 struct dentry *dentry, struct task_struct *task, const void *ptr)
1913 {
1914 const struct pid_entry *p = ptr;
1915 struct inode *inode;
1916 struct proc_inode *ei;
1917 struct dentry *error = ERR_PTR(-EINVAL);
1918
1919 inode = proc_pid_make_inode(dir->i_sb, task);
1920 if (!inode)
1921 goto out;
1922
1923 ei = PROC_I(inode);
1924 inode->i_mode = p->mode;
1925 if (S_ISDIR(inode->i_mode))
1926 inode->i_nlink = 2; /* Use getattr to fix if necessary */
1927 if (p->iop)
1928 inode->i_op = p->iop;
1929 if (p->fop)
1930 inode->i_fop = p->fop;
1931 ei->op = p->op;
1932 dentry->d_op = &pid_dentry_operations;
1933 d_add(dentry, inode);
1934 /* Close the race of the process dying before we return the dentry */
1935 if (pid_revalidate(dentry, NULL))
1936 error = NULL;
1937 out:
1938 return error;
1939 }
1940
1941 static struct dentry *proc_pident_lookup(struct inode *dir,
1942 struct dentry *dentry,
1943 const struct pid_entry *ents,
1944 unsigned int nents)
1945 {
1946 struct inode *inode;
1947 struct dentry *error;
1948 struct task_struct *task = get_proc_task(dir);
1949 const struct pid_entry *p, *last;
1950
1951 error = ERR_PTR(-ENOENT);
1952 inode = NULL;
1953
1954 if (!task)
1955 goto out_no_task;
1956
1957 /*
1958 * Yes, it does not scale. And it should not. Don't add
1959 * new entries into /proc/<tgid>/ without very good reasons.
1960 */
1961 last = &ents[nents - 1];
1962 for (p = ents; p <= last; p++) {
1963 if (p->len != dentry->d_name.len)
1964 continue;
1965 if (!memcmp(dentry->d_name.name, p->name, p->len))
1966 break;
1967 }
1968 if (p > last)
1969 goto out;
1970
1971 error = proc_pident_instantiate(dir, dentry, task, p);
1972 out:
1973 put_task_struct(task);
1974 out_no_task:
1975 return error;
1976 }
1977
1978 static int proc_pident_fill_cache(struct file *filp, void *dirent,
1979 filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
1980 {
1981 return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
1982 proc_pident_instantiate, task, p);
1983 }
1984
1985 static int proc_pident_readdir(struct file *filp,
1986 void *dirent, filldir_t filldir,
1987 const struct pid_entry *ents, unsigned int nents)
1988 {
1989 int i;
1990 struct dentry *dentry = filp->f_path.dentry;
1991 struct inode *inode = dentry->d_inode;
1992 struct task_struct *task = get_proc_task(inode);
1993 const struct pid_entry *p, *last;
1994 ino_t ino;
1995 int ret;
1996
1997 ret = -ENOENT;
1998 if (!task)
1999 goto out_no_task;
2000
2001 ret = 0;
2002 i = filp->f_pos;
2003 switch (i) {
2004 case 0:
2005 ino = inode->i_ino;
2006 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
2007 goto out;
2008 i++;
2009 filp->f_pos++;
2010 /* fall through */
2011 case 1:
2012 ino = parent_ino(dentry);
2013 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
2014 goto out;
2015 i++;
2016 filp->f_pos++;
2017 /* fall through */
2018 default:
2019 i -= 2;
2020 if (i >= nents) {
2021 ret = 1;
2022 goto out;
2023 }
2024 p = ents + i;
2025 last = &ents[nents - 1];
2026 while (p <= last) {
2027 if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0)
2028 goto out;
2029 filp->f_pos++;
2030 p++;
2031 }
2032 }
2033
2034 ret = 1;
2035 out:
2036 put_task_struct(task);
2037 out_no_task:
2038 return ret;
2039 }
2040
2041 #ifdef CONFIG_SECURITY
2042 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
2043 size_t count, loff_t *ppos)
2044 {
2045 struct inode * inode = file->f_path.dentry->d_inode;
2046 char *p = NULL;
2047 ssize_t length;
2048 struct task_struct *task = get_proc_task(inode);
2049
2050 if (!task)
2051 return -ESRCH;
2052
2053 length = security_getprocattr(task,
2054 (char*)file->f_path.dentry->d_name.name,
2055 &p);
2056 put_task_struct(task);
2057 if (length > 0)
2058 length = simple_read_from_buffer(buf, count, ppos, p, length);
2059 kfree(p);
2060 return length;
2061 }
2062
2063 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
2064 size_t count, loff_t *ppos)
2065 {
2066 struct inode * inode = file->f_path.dentry->d_inode;
2067 char *page;
2068 ssize_t length;
2069 struct task_struct *task = get_proc_task(inode);
2070
2071 length = -ESRCH;
2072 if (!task)
2073 goto out_no_task;
2074 if (count > PAGE_SIZE)
2075 count = PAGE_SIZE;
2076
2077 /* No partial writes. */
2078 length = -EINVAL;
2079 if (*ppos != 0)
2080 goto out;
2081
2082 length = -ENOMEM;
2083 page = (char*)__get_free_page(GFP_TEMPORARY);
2084 if (!page)
2085 goto out;
2086
2087 length = -EFAULT;
2088 if (copy_from_user(page, buf, count))
2089 goto out_free;
2090
2091 length = security_setprocattr(task,
2092 (char*)file->f_path.dentry->d_name.name,
2093 (void*)page, count);
2094 out_free:
2095 free_page((unsigned long) page);
2096 out:
2097 put_task_struct(task);
2098 out_no_task:
2099 return length;
2100 }
2101
2102 static const struct file_operations proc_pid_attr_operations = {
2103 .read = proc_pid_attr_read,
2104 .write = proc_pid_attr_write,
2105 };
2106
2107 static const struct pid_entry attr_dir_stuff[] = {
2108 REG("current", S_IRUGO|S_IWUGO, pid_attr),
2109 REG("prev", S_IRUGO, pid_attr),
2110 REG("exec", S_IRUGO|S_IWUGO, pid_attr),
2111 REG("fscreate", S_IRUGO|S_IWUGO, pid_attr),
2112 REG("keycreate", S_IRUGO|S_IWUGO, pid_attr),
2113 REG("sockcreate", S_IRUGO|S_IWUGO, pid_attr),
2114 };
2115
2116 static int proc_attr_dir_readdir(struct file * filp,
2117 void * dirent, filldir_t filldir)
2118 {
2119 return proc_pident_readdir(filp,dirent,filldir,
2120 attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff));
2121 }
2122
2123 static const struct file_operations proc_attr_dir_operations = {
2124 .read = generic_read_dir,
2125 .readdir = proc_attr_dir_readdir,
2126 };
2127
2128 static struct dentry *proc_attr_dir_lookup(struct inode *dir,
2129 struct dentry *dentry, struct nameidata *nd)
2130 {
2131 return proc_pident_lookup(dir, dentry,
2132 attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
2133 }
2134
2135 static const struct inode_operations proc_attr_dir_inode_operations = {
2136 .lookup = proc_attr_dir_lookup,
2137 .getattr = pid_getattr,
2138 .setattr = proc_setattr,
2139 };
2140
2141 #endif
2142
2143 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
2144 static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
2145 size_t count, loff_t *ppos)
2146 {
2147 struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
2148 struct mm_struct *mm;
2149 char buffer[PROC_NUMBUF];
2150 size_t len;
2151 int ret;
2152
2153 if (!task)
2154 return -ESRCH;
2155
2156 ret = 0;
2157 mm = get_task_mm(task);
2158 if (mm) {
2159 len = snprintf(buffer, sizeof(buffer), "%08lx\n",
2160 ((mm->flags & MMF_DUMP_FILTER_MASK) >>
2161 MMF_DUMP_FILTER_SHIFT));
2162 mmput(mm);
2163 ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
2164 }
2165
2166 put_task_struct(task);
2167
2168 return ret;
2169 }
2170
2171 static ssize_t proc_coredump_filter_write(struct file *file,
2172 const char __user *buf,
2173 size_t count,
2174 loff_t *ppos)
2175 {
2176 struct task_struct *task;
2177 struct mm_struct *mm;
2178 char buffer[PROC_NUMBUF], *end;
2179 unsigned int val;
2180 int ret;
2181 int i;
2182 unsigned long mask;
2183
2184 ret = -EFAULT;
2185 memset(buffer, 0, sizeof(buffer));
2186 if (count > sizeof(buffer) - 1)
2187 count = sizeof(buffer) - 1;
2188 if (copy_from_user(buffer, buf, count))
2189 goto out_no_task;
2190
2191 ret = -EINVAL;
2192 val = (unsigned int)simple_strtoul(buffer, &end, 0);
2193 if (*end == '\n')
2194 end++;
2195 if (end - buffer == 0)
2196 goto out_no_task;
2197
2198 ret = -ESRCH;
2199 task = get_proc_task(file->f_dentry->d_inode);
2200 if (!task)
2201 goto out_no_task;
2202
2203 ret = end - buffer;
2204 mm = get_task_mm(task);
2205 if (!mm)
2206 goto out_no_mm;
2207
2208 for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
2209 if (val & mask)
2210 set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2211 else
2212 clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
2213 }
2214
2215 mmput(mm);
2216 out_no_mm:
2217 put_task_struct(task);
2218 out_no_task:
2219 return ret;
2220 }
2221
2222 static const struct file_operations proc_coredump_filter_operations = {
2223 .read = proc_coredump_filter_read,
2224 .write = proc_coredump_filter_write,
2225 };
2226 #endif
2227
2228 /*
2229 * /proc/self:
2230 */
2231 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
2232 int buflen)
2233 {
2234 struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2235 pid_t tgid = task_tgid_nr_ns(current, ns);
2236 char tmp[PROC_NUMBUF];
2237 if (!tgid)
2238 return -ENOENT;
2239 sprintf(tmp, "%d", tgid);
2240 return vfs_readlink(dentry,buffer,buflen,tmp);
2241 }
2242
2243 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
2244 {
2245 struct pid_namespace *ns = dentry->d_sb->s_fs_info;
2246 pid_t tgid = task_tgid_nr_ns(current, ns);
2247 char tmp[PROC_NUMBUF];
2248 if (!tgid)
2249 return ERR_PTR(-ENOENT);
2250 sprintf(tmp, "%d", task_tgid_nr_ns(current, ns));
2251 return ERR_PTR(vfs_follow_link(nd,tmp));
2252 }
2253
2254 static const struct inode_operations proc_self_inode_operations = {
2255 .readlink = proc_self_readlink,
2256 .follow_link = proc_self_follow_link,
2257 };
2258
2259 /*
2260 * proc base
2261 *
2262 * These are the directory entries in the root directory of /proc
2263 * that properly belong to the /proc filesystem, as they describe
2264 * describe something that is process related.
2265 */
2266 static const struct pid_entry proc_base_stuff[] = {
2267 NOD("self", S_IFLNK|S_IRWXUGO,
2268 &proc_self_inode_operations, NULL, {}),
2269 };
2270
2271 /*
2272 * Exceptional case: normally we are not allowed to unhash a busy
2273 * directory. In this case, however, we can do it - no aliasing problems
2274 * due to the way we treat inodes.
2275 */
2276 static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd)
2277 {
2278 struct inode *inode = dentry->d_inode;
2279 struct task_struct *task = get_proc_task(inode);
2280 if (task) {
2281 put_task_struct(task);
2282 return 1;
2283 }
2284 d_drop(dentry);
2285 return 0;
2286 }
2287
2288 static struct dentry_operations proc_base_dentry_operations =
2289 {
2290 .d_revalidate = proc_base_revalidate,
2291 .d_delete = pid_delete_dentry,
2292 };
2293
2294 static struct dentry *proc_base_instantiate(struct inode *dir,
2295 struct dentry *dentry, struct task_struct *task, const void *ptr)
2296 {
2297 const struct pid_entry *p = ptr;
2298 struct inode *inode;
2299 struct proc_inode *ei;
2300 struct dentry *error = ERR_PTR(-EINVAL);
2301
2302 /* Allocate the inode */
2303 error = ERR_PTR(-ENOMEM);
2304 inode = new_inode(dir->i_sb);
2305 if (!inode)
2306 goto out;
2307
2308 /* Initialize the inode */
2309 ei = PROC_I(inode);
2310 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2311
2312 /*
2313 * grab the reference to the task.
2314 */
2315 ei->pid = get_task_pid(task, PIDTYPE_PID);
2316 if (!ei->pid)
2317 goto out_iput;
2318
2319 inode->i_uid = 0;
2320 inode->i_gid = 0;
2321 inode->i_mode = p->mode;
2322 if (S_ISDIR(inode->i_mode))
2323 inode->i_nlink = 2;
2324 if (S_ISLNK(inode->i_mode))
2325 inode->i_size = 64;
2326 if (p->iop)
2327 inode->i_op = p->iop;
2328 if (p->fop)
2329 inode->i_fop = p->fop;
2330 ei->op = p->op;
2331 dentry->d_op = &proc_base_dentry_operations;
2332 d_add(dentry, inode);
2333 error = NULL;
2334 out:
2335 return error;
2336 out_iput:
2337 iput(inode);
2338 goto out;
2339 }
2340
2341 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
2342 {
2343 struct dentry *error;
2344 struct task_struct *task = get_proc_task(dir);
2345 const struct pid_entry *p, *last;
2346
2347 error = ERR_PTR(-ENOENT);
2348
2349 if (!task)
2350 goto out_no_task;
2351
2352 /* Lookup the directory entry */
2353 last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
2354 for (p = proc_base_stuff; p <= last; p++) {
2355 if (p->len != dentry->d_name.len)
2356 continue;
2357 if (!memcmp(dentry->d_name.name, p->name, p->len))
2358 break;
2359 }
2360 if (p > last)
2361 goto out;
2362
2363 error = proc_base_instantiate(dir, dentry, task, p);
2364
2365 out:
2366 put_task_struct(task);
2367 out_no_task:
2368 return error;
2369 }
2370
2371 static int proc_base_fill_cache(struct file *filp, void *dirent,
2372 filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
2373 {
2374 return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
2375 proc_base_instantiate, task, p);
2376 }
2377
2378 #ifdef CONFIG_TASK_IO_ACCOUNTING
2379 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
2380 {
2381 u64 rchar, wchar, syscr, syscw;
2382 struct task_io_accounting ioac;
2383
2384 if (!whole) {
2385 rchar = task->rchar;
2386 wchar = task->wchar;
2387 syscr = task->syscr;
2388 syscw = task->syscw;
2389 memcpy(&ioac, &task->ioac, sizeof(ioac));
2390 } else {
2391 unsigned long flags;
2392 struct task_struct *t = task;
2393 rchar = wchar = syscr = syscw = 0;
2394 memset(&ioac, 0, sizeof(ioac));
2395
2396 rcu_read_lock();
2397 do {
2398 rchar += t->rchar;
2399 wchar += t->wchar;
2400 syscr += t->syscr;
2401 syscw += t->syscw;
2402
2403 ioac.read_bytes += t->ioac.read_bytes;
2404 ioac.write_bytes += t->ioac.write_bytes;
2405 ioac.cancelled_write_bytes +=
2406 t->ioac.cancelled_write_bytes;
2407 t = next_thread(t);
2408 } while (t != task);
2409 rcu_read_unlock();
2410
2411 if (lock_task_sighand(task, &flags)) {
2412 struct signal_struct *sig = task->signal;
2413
2414 rchar += sig->rchar;
2415 wchar += sig->wchar;
2416 syscr += sig->syscr;
2417 syscw += sig->syscw;
2418
2419 ioac.read_bytes += sig->ioac.read_bytes;
2420 ioac.write_bytes += sig->ioac.write_bytes;
2421 ioac.cancelled_write_bytes +=
2422 sig->ioac.cancelled_write_bytes;
2423
2424 unlock_task_sighand(task, &flags);
2425 }
2426 }
2427
2428 return sprintf(buffer,
2429 "rchar: %llu\n"
2430 "wchar: %llu\n"
2431 "syscr: %llu\n"
2432 "syscw: %llu\n"
2433 "read_bytes: %llu\n"
2434 "write_bytes: %llu\n"
2435 "cancelled_write_bytes: %llu\n",
2436 (unsigned long long)rchar,
2437 (unsigned long long)wchar,
2438 (unsigned long long)syscr,
2439 (unsigned long long)syscw,
2440 (unsigned long long)ioac.read_bytes,
2441 (unsigned long long)ioac.write_bytes,
2442 (unsigned long long)ioac.cancelled_write_bytes);
2443 }
2444
2445 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
2446 {
2447 return do_io_accounting(task, buffer, 0);
2448 }
2449
2450 static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
2451 {
2452 return do_io_accounting(task, buffer, 1);
2453 }
2454 #endif /* CONFIG_TASK_IO_ACCOUNTING */
2455
2456 /*
2457 * Thread groups
2458 */
2459 static const struct file_operations proc_task_operations;
2460 static const struct inode_operations proc_task_inode_operations;
2461
2462 static const struct pid_entry tgid_base_stuff[] = {
2463 DIR("task", S_IRUGO|S_IXUGO, task),
2464 DIR("fd", S_IRUSR|S_IXUSR, fd),
2465 DIR("fdinfo", S_IRUSR|S_IXUSR, fdinfo),
2466 #ifdef CONFIG_NET
2467 DIR("net", S_IRUGO|S_IXUGO, net),
2468 #endif
2469 REG("environ", S_IRUSR, environ),
2470 INF("auxv", S_IRUSR, pid_auxv),
2471 ONE("status", S_IRUGO, pid_status),
2472 INF("limits", S_IRUSR, pid_limits),
2473 #ifdef CONFIG_SCHED_DEBUG
2474 REG("sched", S_IRUGO|S_IWUSR, pid_sched),
2475 #endif
2476 INF("cmdline", S_IRUGO, pid_cmdline),
2477 ONE("stat", S_IRUGO, tgid_stat),
2478 ONE("statm", S_IRUGO, pid_statm),
2479 REG("maps", S_IRUGO, maps),
2480 #ifdef CONFIG_NUMA
2481 REG("numa_maps", S_IRUGO, numa_maps),
2482 #endif
2483 REG("mem", S_IRUSR|S_IWUSR, mem),
2484 LNK("cwd", cwd),
2485 LNK("root", root),
2486 LNK("exe", exe),
2487 REG("mounts", S_IRUGO, mounts),
2488 REG("mountinfo", S_IRUGO, mountinfo),
2489 REG("mountstats", S_IRUSR, mountstats),
2490 #ifdef CONFIG_PROC_PAGE_MONITOR
2491 REG("clear_refs", S_IWUSR, clear_refs),
2492 REG("smaps", S_IRUGO, smaps),
2493 REG("pagemap", S_IRUSR, pagemap),
2494 #endif
2495 #ifdef CONFIG_SECURITY
2496 DIR("attr", S_IRUGO|S_IXUGO, attr_dir),
2497 #endif
2498 #ifdef CONFIG_KALLSYMS
2499 INF("wchan", S_IRUGO, pid_wchan),
2500 #endif
2501 #ifdef CONFIG_SCHEDSTATS
2502 INF("schedstat", S_IRUGO, pid_schedstat),
2503 #endif
2504 #ifdef CONFIG_LATENCYTOP
2505 REG("latency", S_IRUGO, lstats),
2506 #endif
2507 #ifdef CONFIG_PROC_PID_CPUSET
2508 REG("cpuset", S_IRUGO, cpuset),
2509 #endif
2510 #ifdef CONFIG_CGROUPS
2511 REG("cgroup", S_IRUGO, cgroup),
2512 #endif
2513 INF("oom_score", S_IRUGO, oom_score),
2514 REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust),
2515 #ifdef CONFIG_AUDITSYSCALL
2516 REG("loginuid", S_IWUSR|S_IRUGO, loginuid),
2517 REG("sessionid", S_IRUGO, sessionid),
2518 #endif
2519 #ifdef CONFIG_FAULT_INJECTION
2520 REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject),
2521 #endif
2522 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
2523 REG("coredump_filter", S_IRUGO|S_IWUSR, coredump_filter),
2524 #endif
2525 #ifdef CONFIG_TASK_IO_ACCOUNTING
2526 INF("io", S_IRUGO, tgid_io_accounting),
2527 #endif
2528 };
2529
2530 static int proc_tgid_base_readdir(struct file * filp,
2531 void * dirent, filldir_t filldir)
2532 {
2533 return proc_pident_readdir(filp,dirent,filldir,
2534 tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
2535 }
2536
2537 static const struct file_operations proc_tgid_base_operations = {
2538 .read = generic_read_dir,
2539 .readdir = proc_tgid_base_readdir,
2540 };
2541
2542 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2543 return proc_pident_lookup(dir, dentry,
2544 tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
2545 }
2546
2547 static const struct inode_operations proc_tgid_base_inode_operations = {
2548 .lookup = proc_tgid_base_lookup,
2549 .getattr = pid_getattr,
2550 .setattr = proc_setattr,
2551 };
2552
2553 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
2554 {
2555 struct dentry *dentry, *leader, *dir;
2556 char buf[PROC_NUMBUF];
2557 struct qstr name;
2558
2559 name.name = buf;
2560 name.len = snprintf(buf, sizeof(buf), "%d", pid);
2561 dentry = d_hash_and_lookup(mnt->mnt_root, &name);
2562 if (dentry) {
2563 if (!(current->flags & PF_EXITING))
2564 shrink_dcache_parent(dentry);
2565 d_drop(dentry);
2566 dput(dentry);
2567 }
2568
2569 if (tgid == 0)
2570 goto out;
2571
2572 name.name = buf;
2573 name.len = snprintf(buf, sizeof(buf), "%d", tgid);
2574 leader = d_hash_and_lookup(mnt->mnt_root, &name);
2575 if (!leader)
2576 goto out;
2577
2578 name.name = "task";
2579 name.len = strlen(name.name);
2580 dir = d_hash_and_lookup(leader, &name);
2581 if (!dir)
2582 goto out_put_leader;
2583
2584 name.name = buf;
2585 name.len = snprintf(buf, sizeof(buf), "%d", pid);
2586 dentry = d_hash_and_lookup(dir, &name);
2587 if (dentry) {
2588 shrink_dcache_parent(dentry);
2589 d_drop(dentry);
2590 dput(dentry);
2591 }
2592
2593 dput(dir);
2594 out_put_leader:
2595 dput(leader);
2596 out:
2597 return;
2598 }
2599
2600 /**
2601 * proc_flush_task - Remove dcache entries for @task from the /proc dcache.
2602 * @task: task that should be flushed.
2603 *
2604 * When flushing dentries from proc, one needs to flush them from global
2605 * proc (proc_mnt) and from all the namespaces' procs this task was seen
2606 * in. This call is supposed to do all of this job.
2607 *
2608 * Looks in the dcache for
2609 * /proc/@pid
2610 * /proc/@tgid/task/@pid
2611 * if either directory is present flushes it and all of it'ts children
2612 * from the dcache.
2613 *
2614 * It is safe and reasonable to cache /proc entries for a task until
2615 * that task exits. After that they just clog up the dcache with
2616 * useless entries, possibly causing useful dcache entries to be
2617 * flushed instead. This routine is proved to flush those useless
2618 * dcache entries at process exit time.
2619 *
2620 * NOTE: This routine is just an optimization so it does not guarantee
2621 * that no dcache entries will exist at process exit time it
2622 * just makes it very unlikely that any will persist.
2623 */
2624
2625 void proc_flush_task(struct task_struct *task)
2626 {
2627 int i;
2628 struct pid *pid, *tgid = NULL;
2629 struct upid *upid;
2630
2631 pid = task_pid(task);
2632 if (thread_group_leader(task))
2633 tgid = task_tgid(task);
2634
2635 for (i = 0; i <= pid->level; i++) {
2636 upid = &pid->numbers[i];
2637 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
2638 tgid ? tgid->numbers[i].nr : 0);
2639 }
2640
2641 upid = &pid->numbers[pid->level];
2642 if (upid->nr == 1)
2643 pid_ns_release_proc(upid->ns);
2644 }
2645
2646 static struct dentry *proc_pid_instantiate(struct inode *dir,
2647 struct dentry * dentry,
2648 struct task_struct *task, const void *ptr)
2649 {
2650 struct dentry *error = ERR_PTR(-ENOENT);
2651 struct inode *inode;
2652
2653 inode = proc_pid_make_inode(dir->i_sb, task);
2654 if (!inode)
2655 goto out;
2656
2657 inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2658 inode->i_op = &proc_tgid_base_inode_operations;
2659 inode->i_fop = &proc_tgid_base_operations;
2660 inode->i_flags|=S_IMMUTABLE;
2661
2662 inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
2663 ARRAY_SIZE(tgid_base_stuff));
2664
2665 dentry->d_op = &pid_dentry_operations;
2666
2667 d_add(dentry, inode);
2668 /* Close the race of the process dying before we return the dentry */
2669 if (pid_revalidate(dentry, NULL))
2670 error = NULL;
2671 out:
2672 return error;
2673 }
2674
2675 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2676 {
2677 struct dentry *result = ERR_PTR(-ENOENT);
2678 struct task_struct *task;
2679 unsigned tgid;
2680 struct pid_namespace *ns;
2681
2682 result = proc_base_lookup(dir, dentry);
2683 if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
2684 goto out;
2685
2686 tgid = name_to_int(dentry);
2687 if (tgid == ~0U)
2688 goto out;
2689
2690 ns = dentry->d_sb->s_fs_info;
2691 rcu_read_lock();
2692 task = find_task_by_pid_ns(tgid, ns);
2693 if (task)
2694 get_task_struct(task);
2695 rcu_read_unlock();
2696 if (!task)
2697 goto out;
2698
2699 result = proc_pid_instantiate(dir, dentry, task, NULL);
2700 put_task_struct(task);
2701 out:
2702 return result;
2703 }
2704
2705 /*
2706 * Find the first task with tgid >= tgid
2707 *
2708 */
2709 struct tgid_iter {
2710 unsigned int tgid;
2711 struct task_struct *task;
2712 };
2713 static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
2714 {
2715 struct pid *pid;
2716
2717 if (iter.task)
2718 put_task_struct(iter.task);
2719 rcu_read_lock();
2720 retry:
2721 iter.task = NULL;
2722 pid = find_ge_pid(iter.tgid, ns);
2723 if (pid) {
2724 iter.tgid = pid_nr_ns(pid, ns);
2725 iter.task = pid_task(pid, PIDTYPE_PID);
2726 /* What we to know is if the pid we have find is the
2727 * pid of a thread_group_leader. Testing for task
2728 * being a thread_group_leader is the obvious thing
2729 * todo but there is a window when it fails, due to
2730 * the pid transfer logic in de_thread.
2731 *
2732 * So we perform the straight forward test of seeing
2733 * if the pid we have found is the pid of a thread
2734 * group leader, and don't worry if the task we have
2735 * found doesn't happen to be a thread group leader.
2736 * As we don't care in the case of readdir.
2737 */
2738 if (!iter.task || !has_group_leader_pid(iter.task)) {
2739 iter.tgid += 1;
2740 goto retry;
2741 }
2742 get_task_struct(iter.task);
2743 }
2744 rcu_read_unlock();
2745 return iter;
2746 }
2747
2748 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
2749
2750 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
2751 struct tgid_iter iter)
2752 {
2753 char name[PROC_NUMBUF];
2754 int len = snprintf(name, sizeof(name), "%d", iter.tgid);
2755 return proc_fill_cache(filp, dirent, filldir, name, len,
2756 proc_pid_instantiate, iter.task, NULL);
2757 }
2758
2759 /* for the /proc/ directory itself, after non-process stuff has been done */
2760 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2761 {
2762 unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2763 struct task_struct *reaper = get_proc_task(filp->f_path.dentry->d_inode);
2764 struct tgid_iter iter;
2765 struct pid_namespace *ns;
2766
2767 if (!reaper)
2768 goto out_no_task;
2769
2770 for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
2771 const struct pid_entry *p = &proc_base_stuff[nr];
2772 if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
2773 goto out;
2774 }
2775
2776 ns = filp->f_dentry->d_sb->s_fs_info;
2777 iter.task = NULL;
2778 iter.tgid = filp->f_pos - TGID_OFFSET;
2779 for (iter = next_tgid(ns, iter);
2780 iter.task;
2781 iter.tgid += 1, iter = next_tgid(ns, iter)) {
2782 filp->f_pos = iter.tgid + TGID_OFFSET;
2783 if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
2784 put_task_struct(iter.task);
2785 goto out;
2786 }
2787 }
2788 filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
2789 out:
2790 put_task_struct(reaper);
2791 out_no_task:
2792 return 0;
2793 }
2794
2795 /*
2796 * Tasks
2797 */
2798 static const struct pid_entry tid_base_stuff[] = {
2799 DIR("fd", S_IRUSR|S_IXUSR, fd),
2800 DIR("fdinfo", S_IRUSR|S_IXUSR, fdinfo),
2801 REG("environ", S_IRUSR, environ),
2802 INF("auxv", S_IRUSR, pid_auxv),
2803 ONE("status", S_IRUGO, pid_status),
2804 INF("limits", S_IRUSR, pid_limits),
2805 #ifdef CONFIG_SCHED_DEBUG
2806 REG("sched", S_IRUGO|S_IWUSR, pid_sched),
2807 #endif
2808 INF("cmdline", S_IRUGO, pid_cmdline),
2809 ONE("stat", S_IRUGO, tid_stat),
2810 ONE("statm", S_IRUGO, pid_statm),
2811 REG("maps", S_IRUGO, maps),
2812 #ifdef CONFIG_NUMA
2813 REG("numa_maps", S_IRUGO, numa_maps),
2814 #endif
2815 REG("mem", S_IRUSR|S_IWUSR, mem),
2816 LNK("cwd", cwd),
2817 LNK("root", root),
2818 LNK("exe", exe),
2819 REG("mounts", S_IRUGO, mounts),
2820 REG("mountinfo", S_IRUGO, mountinfo),
2821 #ifdef CONFIG_PROC_PAGE_MONITOR
2822 REG("clear_refs", S_IWUSR, clear_refs),
2823 REG("smaps", S_IRUGO, smaps),
2824 REG("pagemap", S_IRUSR, pagemap),
2825 #endif
2826 #ifdef CONFIG_SECURITY
2827 DIR("attr", S_IRUGO|S_IXUGO, attr_dir),
2828 #endif
2829 #ifdef CONFIG_KALLSYMS
2830 INF("wchan", S_IRUGO, pid_wchan),
2831 #endif
2832 #ifdef CONFIG_SCHEDSTATS
2833 INF("schedstat", S_IRUGO, pid_schedstat),
2834 #endif
2835 #ifdef CONFIG_LATENCYTOP
2836 REG("latency", S_IRUGO, lstats),
2837 #endif
2838 #ifdef CONFIG_PROC_PID_CPUSET
2839 REG("cpuset", S_IRUGO, cpuset),
2840 #endif
2841 #ifdef CONFIG_CGROUPS
2842 REG("cgroup", S_IRUGO, cgroup),
2843 #endif
2844 INF("oom_score", S_IRUGO, oom_score),
2845 REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust),
2846 #ifdef CONFIG_AUDITSYSCALL
2847 REG("loginuid", S_IWUSR|S_IRUGO, loginuid),
2848 REG("sessionid", S_IRUSR, sessionid),
2849 #endif
2850 #ifdef CONFIG_FAULT_INJECTION
2851 REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject),
2852 #endif
2853 #ifdef CONFIG_TASK_IO_ACCOUNTING
2854 INF("io", S_IRUGO, tid_io_accounting),
2855 #endif
2856 };
2857
2858 static int proc_tid_base_readdir(struct file * filp,
2859 void * dirent, filldir_t filldir)
2860 {
2861 return proc_pident_readdir(filp,dirent,filldir,
2862 tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
2863 }
2864
2865 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
2866 return proc_pident_lookup(dir, dentry,
2867 tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
2868 }
2869
2870 static const struct file_operations proc_tid_base_operations = {
2871 .read = generic_read_dir,
2872 .readdir = proc_tid_base_readdir,
2873 };
2874
2875 static const struct inode_operations proc_tid_base_inode_operations = {
2876 .lookup = proc_tid_base_lookup,
2877 .getattr = pid_getattr,
2878 .setattr = proc_setattr,
2879 };
2880
2881 static struct dentry *proc_task_instantiate(struct inode *dir,
2882 struct dentry *dentry, struct task_struct *task, const void *ptr)
2883 {
2884 struct dentry *error = ERR_PTR(-ENOENT);
2885 struct inode *inode;
2886 inode = proc_pid_make_inode(dir->i_sb, task);
2887
2888 if (!inode)
2889 goto out;
2890 inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2891 inode->i_op = &proc_tid_base_inode_operations;
2892 inode->i_fop = &proc_tid_base_operations;
2893 inode->i_flags|=S_IMMUTABLE;
2894
2895 inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
2896 ARRAY_SIZE(tid_base_stuff));
2897
2898 dentry->d_op = &pid_dentry_operations;
2899
2900 d_add(dentry, inode);
2901 /* Close the race of the process dying before we return the dentry */
2902 if (pid_revalidate(dentry, NULL))
2903 error = NULL;
2904 out:
2905 return error;
2906 }
2907
2908 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2909 {
2910 struct dentry *result = ERR_PTR(-ENOENT);
2911 struct task_struct *task;
2912 struct task_struct *leader = get_proc_task(dir);
2913 unsigned tid;
2914 struct pid_namespace *ns;
2915
2916 if (!leader)
2917 goto out_no_task;
2918
2919 tid = name_to_int(dentry);
2920 if (tid == ~0U)
2921 goto out;
2922
2923 ns = dentry->d_sb->s_fs_info;
2924 rcu_read_lock();
2925 task = find_task_by_pid_ns(tid, ns);
2926 if (task)
2927 get_task_struct(task);
2928 rcu_read_unlock();
2929 if (!task)
2930 goto out;
2931 if (!same_thread_group(leader, task))
2932 goto out_drop_task;
2933
2934 result = proc_task_instantiate(dir, dentry, task, NULL);
2935 out_drop_task:
2936 put_task_struct(task);
2937 out:
2938 put_task_struct(leader);
2939 out_no_task:
2940 return result;
2941 }
2942
2943 /*
2944 * Find the first tid of a thread group to return to user space.
2945 *
2946 * Usually this is just the thread group leader, but if the users
2947 * buffer was too small or there was a seek into the middle of the
2948 * directory we have more work todo.
2949 *
2950 * In the case of a short read we start with find_task_by_pid.
2951 *
2952 * In the case of a seek we start with the leader and walk nr
2953 * threads past it.
2954 */
2955 static struct task_struct *first_tid(struct task_struct *leader,
2956 int tid, int nr, struct pid_namespace *ns)
2957 {
2958 struct task_struct *pos;
2959
2960 rcu_read_lock();
2961 /* Attempt to start with the pid of a thread */
2962 if (tid && (nr > 0)) {
2963 pos = find_task_by_pid_ns(tid, ns);
2964 if (pos && (pos->group_leader == leader))
2965 goto found;
2966 }
2967
2968 /* If nr exceeds the number of threads there is nothing todo */
2969 pos = NULL;
2970 if (nr && nr >= get_nr_threads(leader))
2971 goto out;
2972
2973 /* If we haven't found our starting place yet start
2974 * with the leader and walk nr threads forward.
2975 */
2976 for (pos = leader; nr > 0; --nr) {
2977 pos = next_thread(pos);
2978 if (pos == leader) {
2979 pos = NULL;
2980 goto out;
2981 }
2982 }
2983 found:
2984 get_task_struct(pos);
2985 out:
2986 rcu_read_unlock();
2987 return pos;
2988 }
2989
2990 /*
2991 * Find the next thread in the thread list.
2992 * Return NULL if there is an error or no next thread.
2993 *
2994 * The reference to the input task_struct is released.
2995 */
2996 static struct task_struct *next_tid(struct task_struct *start)
2997 {
2998 struct task_struct *pos = NULL;
2999 rcu_read_lock();
3000 if (pid_alive(start)) {
3001 pos = next_thread(start);
3002 if (thread_group_leader(pos))
3003 pos = NULL;
3004 else
3005 get_task_struct(pos);
3006 }
3007 rcu_read_unlock();
3008 put_task_struct(start);
3009 return pos;
3010 }
3011
3012 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
3013 struct task_struct *task, int tid)
3014 {
3015 char name[PROC_NUMBUF];
3016 int len = snprintf(name, sizeof(name), "%d", tid);
3017 return proc_fill_cache(filp, dirent, filldir, name, len,
3018 proc_task_instantiate, task, NULL);
3019 }
3020
3021 /* for the /proc/TGID/task/ directories */
3022 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
3023 {
3024 struct dentry *dentry = filp->f_path.dentry;
3025 struct inode *inode = dentry->d_inode;
3026 struct task_struct *leader = NULL;
3027 struct task_struct *task;
3028 int retval = -ENOENT;
3029 ino_t ino;
3030 int tid;
3031 unsigned long pos = filp->f_pos; /* avoiding "long long" filp->f_pos */
3032 struct pid_namespace *ns;
3033
3034 task = get_proc_task(inode);
3035 if (!task)
3036 goto out_no_task;
3037 rcu_read_lock();
3038 if (pid_alive(task)) {
3039 leader = task->group_leader;
3040 get_task_struct(leader);
3041 }
3042 rcu_read_unlock();
3043 put_task_struct(task);
3044 if (!leader)
3045 goto out_no_task;
3046 retval = 0;
3047
3048 switch (pos) {
3049 case 0:
3050 ino = inode->i_ino;
3051 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
3052 goto out;
3053 pos++;
3054 /* fall through */
3055 case 1:
3056 ino = parent_ino(dentry);
3057 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
3058 goto out;
3059 pos++;
3060 /* fall through */
3061 }
3062
3063 /* f_version caches the tgid value that the last readdir call couldn't
3064 * return. lseek aka telldir automagically resets f_version to 0.
3065 */
3066 ns = filp->f_dentry->d_sb->s_fs_info;
3067 tid = (int)filp->f_version;
3068 filp->f_version = 0;
3069 for (task = first_tid(leader, tid, pos - 2, ns);
3070 task;
3071 task = next_tid(task), pos++) {
3072 tid = task_pid_nr_ns(task, ns);
3073 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
3074 /* returning this tgid failed, save it as the first
3075 * pid for the next readir call */
3076 filp->f_version = (u64)tid;
3077 put_task_struct(task);
3078 break;
3079 }
3080 }
3081 out:
3082 filp->f_pos = pos;
3083 put_task_struct(leader);
3084 out_no_task:
3085 return retval;
3086 }
3087
3088 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
3089 {
3090 struct inode *inode = dentry->d_inode;
3091 struct task_struct *p = get_proc_task(inode);
3092 generic_fillattr(inode, stat);
3093
3094 if (p) {
3095 rcu_read_lock();
3096 stat->nlink += get_nr_threads(p);
3097 rcu_read_unlock();
3098 put_task_struct(p);
3099 }
3100
3101 return 0;
3102 }
3103
3104 static const struct inode_operations proc_task_inode_operations = {
3105 .lookup = proc_task_lookup,
3106 .getattr = proc_task_getattr,
3107 .setattr = proc_setattr,
3108 };
3109
3110 static const struct file_operations proc_task_operations = {
3111 .read = generic_read_dir,
3112 .readdir = proc_task_readdir,
3113 };
Linux with added FPC-III support