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11#include <linux/errno.h>
12#include <linux/time.h>
13#include <linux/proc_fs.h>
14#include <linux/stat.h>
15#include <linux/module.h>
16#include <linux/mount.h>
17#include <linux/init.h>
18#include <linux/idr.h>
19#include <linux/namei.h>
20#include <linux/bitops.h>
21#include <linux/spinlock.h>
22#include <linux/completion.h>
23#include <asm/uaccess.h>
24
25#include "internal.h"
26
27DEFINE_SPINLOCK(proc_subdir_lock);
28
29static int proc_match(int len, const char *name, struct proc_dir_entry *de)
30{
31 if (de->namelen != len)
32 return 0;
33 return !memcmp(name, de->name, len);
34}
35
36
37#define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
38
39static ssize_t
40__proc_file_read(struct file *file, char __user *buf, size_t nbytes,
41 loff_t *ppos)
42{
43 struct inode * inode = file->f_path.dentry->d_inode;
44 char *page;
45 ssize_t retval=0;
46 int eof=0;
47 ssize_t n, count;
48 char *start;
49 struct proc_dir_entry * dp;
50 unsigned long long pos;
51
52
53
54
55
56
57 pos = *ppos;
58 if (pos > MAX_NON_LFS)
59 return 0;
60 if (nbytes > MAX_NON_LFS - pos)
61 nbytes = MAX_NON_LFS - pos;
62
63 dp = PDE(inode);
64 if (!(page = (char*) __get_free_page(GFP_TEMPORARY)))
65 return -ENOMEM;
66
67 while ((nbytes > 0) && !eof) {
68 count = min_t(size_t, PROC_BLOCK_SIZE, nbytes);
69
70 start = NULL;
71 if (dp->read_proc) {
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118
119 n = dp->read_proc(page, &start, *ppos,
120 count, &eof, dp->data);
121 } else
122 break;
123
124 if (n == 0)
125 break;
126 if (n < 0) {
127 if (retval == 0)
128 retval = n;
129 break;
130 }
131
132 if (start == NULL) {
133 if (n > PAGE_SIZE) {
134 printk(KERN_ERR
135 "proc_file_read: Apparent buffer overflow!\n");
136 n = PAGE_SIZE;
137 }
138 n -= *ppos;
139 if (n <= 0)
140 break;
141 if (n > count)
142 n = count;
143 start = page + *ppos;
144 } else if (start < page) {
145 if (n > PAGE_SIZE) {
146 printk(KERN_ERR
147 "proc_file_read: Apparent buffer overflow!\n");
148 n = PAGE_SIZE;
149 }
150 if (n > count) {
151
152
153
154
155 printk(KERN_WARNING
156 "proc_file_read: Read count exceeded\n");
157 }
158 } else {
159 unsigned long startoff = (unsigned long)(start - page);
160 if (n > (PAGE_SIZE - startoff)) {
161 printk(KERN_ERR
162 "proc_file_read: Apparent buffer overflow!\n");
163 n = PAGE_SIZE - startoff;
164 }
165 if (n > count)
166 n = count;
167 }
168
169 n -= copy_to_user(buf, start < page ? page : start, n);
170 if (n == 0) {
171 if (retval == 0)
172 retval = -EFAULT;
173 break;
174 }
175
176 *ppos += start < page ? (unsigned long)start : n;
177 nbytes -= n;
178 buf += n;
179 retval += n;
180 }
181 free_page((unsigned long) page);
182 return retval;
183}
184
185static ssize_t
186proc_file_read(struct file *file, char __user *buf, size_t nbytes,
187 loff_t *ppos)
188{
189 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
190 ssize_t rv = -EIO;
191
192 spin_lock(&pde->pde_unload_lock);
193 if (!pde->proc_fops) {
194 spin_unlock(&pde->pde_unload_lock);
195 return rv;
196 }
197 pde->pde_users++;
198 spin_unlock(&pde->pde_unload_lock);
199
200 rv = __proc_file_read(file, buf, nbytes, ppos);
201
202 pde_users_dec(pde);
203 return rv;
204}
205
206static ssize_t
207proc_file_write(struct file *file, const char __user *buffer,
208 size_t count, loff_t *ppos)
209{
210 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
211 ssize_t rv = -EIO;
212
213 if (pde->write_proc) {
214 spin_lock(&pde->pde_unload_lock);
215 if (!pde->proc_fops) {
216 spin_unlock(&pde->pde_unload_lock);
217 return rv;
218 }
219 pde->pde_users++;
220 spin_unlock(&pde->pde_unload_lock);
221
222
223 rv = pde->write_proc(file, buffer, count, pde->data);
224 pde_users_dec(pde);
225 }
226 return rv;
227}
228
229
230static loff_t
231proc_file_lseek(struct file *file, loff_t offset, int orig)
232{
233 loff_t retval = -EINVAL;
234 switch (orig) {
235 case 1:
236 offset += file->f_pos;
237
238 case 0:
239 if (offset < 0 || offset > MAX_NON_LFS)
240 break;
241 file->f_pos = retval = offset;
242 }
243 return retval;
244}
245
246static const struct file_operations proc_file_operations = {
247 .llseek = proc_file_lseek,
248 .read = proc_file_read,
249 .write = proc_file_write,
250};
251
252static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
253{
254 struct inode *inode = dentry->d_inode;
255 struct proc_dir_entry *de = PDE(inode);
256 int error;
257
258 error = inode_change_ok(inode, iattr);
259 if (error)
260 goto out;
261
262 error = inode_setattr(inode, iattr);
263 if (error)
264 goto out;
265
266 de->uid = inode->i_uid;
267 de->gid = inode->i_gid;
268 de->mode = inode->i_mode;
269out:
270 return error;
271}
272
273static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
274 struct kstat *stat)
275{
276 struct inode *inode = dentry->d_inode;
277 struct proc_dir_entry *de = PROC_I(inode)->pde;
278 if (de && de->nlink)
279 inode->i_nlink = de->nlink;
280
281 generic_fillattr(inode, stat);
282 return 0;
283}
284
285static const struct inode_operations proc_file_inode_operations = {
286 .setattr = proc_notify_change,
287};
288
289
290
291
292
293
294static int xlate_proc_name(const char *name,
295 struct proc_dir_entry **ret, const char **residual)
296{
297 const char *cp = name, *next;
298 struct proc_dir_entry *de;
299 int len;
300 int rtn = 0;
301
302 de = *ret;
303 if (!de)
304 de = &proc_root;
305
306 spin_lock(&proc_subdir_lock);
307 while (1) {
308 next = strchr(cp, '/');
309 if (!next)
310 break;
311
312 len = next - cp;
313 for (de = de->subdir; de ; de = de->next) {
314 if (proc_match(len, cp, de))
315 break;
316 }
317 if (!de) {
318 rtn = -ENOENT;
319 goto out;
320 }
321 cp += len + 1;
322 }
323 *residual = cp;
324 *ret = de;
325out:
326 spin_unlock(&proc_subdir_lock);
327 return rtn;
328}
329
330static DEFINE_IDA(proc_inum_ida);
331static DEFINE_SPINLOCK(proc_inum_lock);
332
333#define PROC_DYNAMIC_FIRST 0xF0000000U
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353
354static unsigned int get_inode_number(void)
355{
356 unsigned int i;
357 int error;
358
359retry:
360 if (ida_pre_get(&proc_inum_ida, GFP_KERNEL) == 0)
361 return 0;
362
363 spin_lock(&proc_inum_lock);
364 error = ida_get_new(&proc_inum_ida, &i);
365 spin_unlock(&proc_inum_lock);
366 if (error == -EAGAIN)
367 goto retry;
368 else if (error)
369 return 0;
370
371 if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
372 spin_lock(&proc_inum_lock);
373 ida_remove(&proc_inum_ida, i);
374 spin_unlock(&proc_inum_lock);
375 return 0;
376 }
377 return PROC_DYNAMIC_FIRST + i;
378}
379
380static void release_inode_number(unsigned int inum)
381{
382 spin_lock(&proc_inum_lock);
383 ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
384 spin_unlock(&proc_inum_lock);
385}
386
387static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
388{
389 nd_set_link(nd, PDE(dentry->d_inode)->data);
390 return NULL;
391}
392
393static const struct inode_operations proc_link_inode_operations = {
394 .readlink = generic_readlink,
395 .follow_link = proc_follow_link,
396};
397
398
399
400
401
402
403
404static int proc_delete_dentry(struct dentry * dentry)
405{
406 return 1;
407}
408
409static const struct dentry_operations proc_dentry_operations =
410{
411 .d_delete = proc_delete_dentry,
412};
413
414
415
416
417
418struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
419 struct dentry *dentry)
420{
421 struct inode *inode = NULL;
422 int error = -ENOENT;
423
424 spin_lock(&proc_subdir_lock);
425 for (de = de->subdir; de ; de = de->next) {
426 if (de->namelen != dentry->d_name.len)
427 continue;
428 if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
429 unsigned int ino;
430
431 ino = de->low_ino;
432 de_get(de);
433 spin_unlock(&proc_subdir_lock);
434 error = -EINVAL;
435 inode = proc_get_inode(dir->i_sb, ino, de);
436 goto out_unlock;
437 }
438 }
439 spin_unlock(&proc_subdir_lock);
440out_unlock:
441
442 if (inode) {
443 dentry->d_op = &proc_dentry_operations;
444 d_add(dentry, inode);
445 return NULL;
446 }
447 if (de)
448 de_put(de);
449 return ERR_PTR(error);
450}
451
452struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
453 struct nameidata *nd)
454{
455 return proc_lookup_de(PDE(dir), dir, dentry);
456}
457
458
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460
461
462
463
464
465
466
467int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent,
468 filldir_t filldir)
469{
470 unsigned int ino;
471 int i;
472 struct inode *inode = filp->f_path.dentry->d_inode;
473 int ret = 0;
474
475 ino = inode->i_ino;
476 i = filp->f_pos;
477 switch (i) {
478 case 0:
479 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
480 goto out;
481 i++;
482 filp->f_pos++;
483
484 case 1:
485 if (filldir(dirent, "..", 2, i,
486 parent_ino(filp->f_path.dentry),
487 DT_DIR) < 0)
488 goto out;
489 i++;
490 filp->f_pos++;
491
492 default:
493 spin_lock(&proc_subdir_lock);
494 de = de->subdir;
495 i -= 2;
496 for (;;) {
497 if (!de) {
498 ret = 1;
499 spin_unlock(&proc_subdir_lock);
500 goto out;
501 }
502 if (!i)
503 break;
504 de = de->next;
505 i--;
506 }
507
508 do {
509 struct proc_dir_entry *next;
510
511
512 de_get(de);
513 spin_unlock(&proc_subdir_lock);
514 if (filldir(dirent, de->name, de->namelen, filp->f_pos,
515 de->low_ino, de->mode >> 12) < 0) {
516 de_put(de);
517 goto out;
518 }
519 spin_lock(&proc_subdir_lock);
520 filp->f_pos++;
521 next = de->next;
522 de_put(de);
523 de = next;
524 } while (de);
525 spin_unlock(&proc_subdir_lock);
526 }
527 ret = 1;
528out:
529 return ret;
530}
531
532int proc_readdir(struct file *filp, void *dirent, filldir_t filldir)
533{
534 struct inode *inode = filp->f_path.dentry->d_inode;
535
536 return proc_readdir_de(PDE(inode), filp, dirent, filldir);
537}
538
539
540
541
542
543
544static const struct file_operations proc_dir_operations = {
545 .llseek = generic_file_llseek,
546 .read = generic_read_dir,
547 .readdir = proc_readdir,
548};
549
550
551
552
553static const struct inode_operations proc_dir_inode_operations = {
554 .lookup = proc_lookup,
555 .getattr = proc_getattr,
556 .setattr = proc_notify_change,
557};
558
559static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
560{
561 unsigned int i;
562 struct proc_dir_entry *tmp;
563
564 i = get_inode_number();
565 if (i == 0)
566 return -EAGAIN;
567 dp->low_ino = i;
568
569 if (S_ISDIR(dp->mode)) {
570 if (dp->proc_iops == NULL) {
571 dp->proc_fops = &proc_dir_operations;
572 dp->proc_iops = &proc_dir_inode_operations;
573 }
574 dir->nlink++;
575 } else if (S_ISLNK(dp->mode)) {
576 if (dp->proc_iops == NULL)
577 dp->proc_iops = &proc_link_inode_operations;
578 } else if (S_ISREG(dp->mode)) {
579 if (dp->proc_fops == NULL)
580 dp->proc_fops = &proc_file_operations;
581 if (dp->proc_iops == NULL)
582 dp->proc_iops = &proc_file_inode_operations;
583 }
584
585 spin_lock(&proc_subdir_lock);
586
587 for (tmp = dir->subdir; tmp; tmp = tmp->next)
588 if (strcmp(tmp->name, dp->name) == 0) {
589 WARN(1, KERN_WARNING "proc_dir_entry '%s/%s' already registered\n",
590 dir->name, dp->name);
591 break;
592 }
593
594 dp->next = dir->subdir;
595 dp->parent = dir;
596 dir->subdir = dp;
597 spin_unlock(&proc_subdir_lock);
598
599 return 0;
600}
601
602static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
603 const char *name,
604 mode_t mode,
605 nlink_t nlink)
606{
607 struct proc_dir_entry *ent = NULL;
608 const char *fn = name;
609 int len;
610
611
612 if (!name || !strlen(name)) goto out;
613
614 if (xlate_proc_name(name, parent, &fn) != 0)
615 goto out;
616
617
618 if (strchr(fn, '/'))
619 goto out;
620
621 len = strlen(fn);
622
623 ent = kmalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
624 if (!ent) goto out;
625
626 memset(ent, 0, sizeof(struct proc_dir_entry));
627 memcpy(((char *) ent) + sizeof(struct proc_dir_entry), fn, len + 1);
628 ent->name = ((char *) ent) + sizeof(*ent);
629 ent->namelen = len;
630 ent->mode = mode;
631 ent->nlink = nlink;
632 atomic_set(&ent->count, 1);
633 ent->pde_users = 0;
634 spin_lock_init(&ent->pde_unload_lock);
635 ent->pde_unload_completion = NULL;
636 INIT_LIST_HEAD(&ent->pde_openers);
637 out:
638 return ent;
639}
640
641struct proc_dir_entry *proc_symlink(const char *name,
642 struct proc_dir_entry *parent, const char *dest)
643{
644 struct proc_dir_entry *ent;
645
646 ent = __proc_create(&parent, name,
647 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
648
649 if (ent) {
650 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
651 if (ent->data) {
652 strcpy((char*)ent->data,dest);
653 if (proc_register(parent, ent) < 0) {
654 kfree(ent->data);
655 kfree(ent);
656 ent = NULL;
657 }
658 } else {
659 kfree(ent);
660 ent = NULL;
661 }
662 }
663 return ent;
664}
665
666struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
667 struct proc_dir_entry *parent)
668{
669 struct proc_dir_entry *ent;
670
671 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
672 if (ent) {
673 if (proc_register(parent, ent) < 0) {
674 kfree(ent);
675 ent = NULL;
676 }
677 }
678 return ent;
679}
680
681struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name,
682 struct proc_dir_entry *parent)
683{
684 struct proc_dir_entry *ent;
685
686 ent = __proc_create(&parent, name, S_IFDIR | S_IRUGO | S_IXUGO, 2);
687 if (ent) {
688 ent->data = net;
689 if (proc_register(parent, ent) < 0) {
690 kfree(ent);
691 ent = NULL;
692 }
693 }
694 return ent;
695}
696EXPORT_SYMBOL_GPL(proc_net_mkdir);
697
698struct proc_dir_entry *proc_mkdir(const char *name,
699 struct proc_dir_entry *parent)
700{
701 return proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
702}
703
704struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
705 struct proc_dir_entry *parent)
706{
707 struct proc_dir_entry *ent;
708 nlink_t nlink;
709
710 if (S_ISDIR(mode)) {
711 if ((mode & S_IALLUGO) == 0)
712 mode |= S_IRUGO | S_IXUGO;
713 nlink = 2;
714 } else {
715 if ((mode & S_IFMT) == 0)
716 mode |= S_IFREG;
717 if ((mode & S_IALLUGO) == 0)
718 mode |= S_IRUGO;
719 nlink = 1;
720 }
721
722 ent = __proc_create(&parent, name, mode, nlink);
723 if (ent) {
724 if (proc_register(parent, ent) < 0) {
725 kfree(ent);
726 ent = NULL;
727 }
728 }
729 return ent;
730}
731
732struct proc_dir_entry *proc_create_data(const char *name, mode_t mode,
733 struct proc_dir_entry *parent,
734 const struct file_operations *proc_fops,
735 void *data)
736{
737 struct proc_dir_entry *pde;
738 nlink_t nlink;
739
740 if (S_ISDIR(mode)) {
741 if ((mode & S_IALLUGO) == 0)
742 mode |= S_IRUGO | S_IXUGO;
743 nlink = 2;
744 } else {
745 if ((mode & S_IFMT) == 0)
746 mode |= S_IFREG;
747 if ((mode & S_IALLUGO) == 0)
748 mode |= S_IRUGO;
749 nlink = 1;
750 }
751
752 pde = __proc_create(&parent, name, mode, nlink);
753 if (!pde)
754 goto out;
755 pde->proc_fops = proc_fops;
756 pde->data = data;
757 if (proc_register(parent, pde) < 0)
758 goto out_free;
759 return pde;
760out_free:
761 kfree(pde);
762out:
763 return NULL;
764}
765
766void free_proc_entry(struct proc_dir_entry *de)
767{
768 unsigned int ino = de->low_ino;
769
770 if (ino < PROC_DYNAMIC_FIRST)
771 return;
772
773 release_inode_number(ino);
774
775 if (S_ISLNK(de->mode))
776 kfree(de->data);
777 kfree(de);
778}
779
780
781
782
783void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
784{
785 struct proc_dir_entry **p;
786 struct proc_dir_entry *de = NULL;
787 const char *fn = name;
788 int len;
789
790 if (xlate_proc_name(name, &parent, &fn) != 0)
791 return;
792 len = strlen(fn);
793
794 spin_lock(&proc_subdir_lock);
795 for (p = &parent->subdir; *p; p=&(*p)->next ) {
796 if (proc_match(len, fn, *p)) {
797 de = *p;
798 *p = de->next;
799 de->next = NULL;
800 break;
801 }
802 }
803 spin_unlock(&proc_subdir_lock);
804 if (!de)
805 return;
806
807 spin_lock(&de->pde_unload_lock);
808
809
810
811
812 de->proc_fops = NULL;
813
814 if (de->pde_users > 0) {
815 DECLARE_COMPLETION_ONSTACK(c);
816
817 if (!de->pde_unload_completion)
818 de->pde_unload_completion = &c;
819
820 spin_unlock(&de->pde_unload_lock);
821
822 wait_for_completion(de->pde_unload_completion);
823
824 goto continue_removing;
825 }
826 spin_unlock(&de->pde_unload_lock);
827
828continue_removing:
829 spin_lock(&de->pde_unload_lock);
830 while (!list_empty(&de->pde_openers)) {
831 struct pde_opener *pdeo;
832
833 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
834 list_del(&pdeo->lh);
835 spin_unlock(&de->pde_unload_lock);
836 pdeo->release(pdeo->inode, pdeo->file);
837 kfree(pdeo);
838 spin_lock(&de->pde_unload_lock);
839 }
840 spin_unlock(&de->pde_unload_lock);
841
842 if (S_ISDIR(de->mode))
843 parent->nlink--;
844 de->nlink = 0;
845 WARN(de->subdir, KERN_WARNING "%s: removing non-empty directory "
846 "'%s/%s', leaking at least '%s'\n", __func__,
847 de->parent->name, de->name, de->subdir->name);
848 if (atomic_dec_and_test(&de->count))
849 free_proc_entry(de);
850}
851