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[PATCH] uml: hostfs - fix possible PAGE_CACHE_SHIFT overflows
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / hostfs / hostfs_kern.c
1 /*
2 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
4 *
5 * Ported the filesystem routines to 2.5.
6 * 2003-02-10 Petr Baudis <pasky@ucw.cz>
7 */
8
9 #include <linux/stddef.h>
10 #include <linux/fs.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/slab.h>
14 #include <linux/pagemap.h>
15 #include <linux/blkdev.h>
16 #include <linux/list.h>
17 #include <linux/statfs.h>
18 #include <linux/kdev_t.h>
19 #include <asm/uaccess.h>
20 #include "hostfs.h"
21 #include "kern_util.h"
22 #include "kern.h"
23 #include "user_util.h"
24 #include "init.h"
25
26 struct hostfs_inode_info {
27 char *host_filename;
28 int fd;
29 int mode;
30 struct inode vfs_inode;
31 };
32
33 static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
34 {
35 return(list_entry(inode, struct hostfs_inode_info, vfs_inode));
36 }
37
38 #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_dentry->d_inode)
39
40 int hostfs_d_delete(struct dentry *dentry)
41 {
42 return(1);
43 }
44
45 struct dentry_operations hostfs_dentry_ops = {
46 .d_delete = hostfs_d_delete,
47 };
48
49 /* Changed in hostfs_args before the kernel starts running */
50 static char *root_ino = "/";
51 static int append = 0;
52
53 #define HOSTFS_SUPER_MAGIC 0x00c0ffee
54
55 static struct inode_operations hostfs_iops;
56 static struct inode_operations hostfs_dir_iops;
57 static struct address_space_operations hostfs_link_aops;
58
59 #ifndef MODULE
60 static int __init hostfs_args(char *options, int *add)
61 {
62 char *ptr;
63
64 ptr = strchr(options, ',');
65 if(ptr != NULL)
66 *ptr++ = '\0';
67 if(*options != '\0')
68 root_ino = options;
69
70 options = ptr;
71 while(options){
72 ptr = strchr(options, ',');
73 if(ptr != NULL)
74 *ptr++ = '\0';
75 if(*options != '\0'){
76 if(!strcmp(options, "append"))
77 append = 1;
78 else printf("hostfs_args - unsupported option - %s\n",
79 options);
80 }
81 options = ptr;
82 }
83 return(0);
84 }
85
86 __uml_setup("hostfs=", hostfs_args,
87 "hostfs=<root dir>,<flags>,...\n"
88 " This is used to set hostfs parameters. The root directory argument\n"
89 " is used to confine all hostfs mounts to within the specified directory\n"
90 " tree on the host. If this isn't specified, then a user inside UML can\n"
91 " mount anything on the host that's accessible to the user that's running\n"
92 " it.\n"
93 " The only flag currently supported is 'append', which specifies that all\n"
94 " files opened by hostfs will be opened in append mode.\n\n"
95 );
96 #endif
97
98 static char *dentry_name(struct dentry *dentry, int extra)
99 {
100 struct dentry *parent;
101 char *root, *name;
102 int len;
103
104 len = 0;
105 parent = dentry;
106 while(parent->d_parent != parent){
107 len += parent->d_name.len + 1;
108 parent = parent->d_parent;
109 }
110
111 root = HOSTFS_I(parent->d_inode)->host_filename;
112 len += strlen(root);
113 name = kmalloc(len + extra + 1, GFP_KERNEL);
114 if(name == NULL) return(NULL);
115
116 name[len] = '\0';
117 parent = dentry;
118 while(parent->d_parent != parent){
119 len -= parent->d_name.len + 1;
120 name[len] = '/';
121 strncpy(&name[len + 1], parent->d_name.name,
122 parent->d_name.len);
123 parent = parent->d_parent;
124 }
125 strncpy(name, root, strlen(root));
126 return(name);
127 }
128
129 static char *inode_name(struct inode *ino, int extra)
130 {
131 struct dentry *dentry;
132
133 dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias);
134 return(dentry_name(dentry, extra));
135 }
136
137 static int read_name(struct inode *ino, char *name)
138 {
139 /* The non-int inode fields are copied into ints by stat_file and
140 * then copied into the inode because passing the actual pointers
141 * in and having them treated as int * breaks on big-endian machines
142 */
143 int err;
144 int i_mode, i_nlink, i_blksize;
145 unsigned long long i_size;
146 unsigned long long i_ino;
147 unsigned long long i_blocks;
148
149 err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid,
150 &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime,
151 &ino->i_ctime, &i_blksize, &i_blocks);
152 if(err)
153 return(err);
154
155 ino->i_ino = i_ino;
156 ino->i_mode = i_mode;
157 ino->i_nlink = i_nlink;
158 ino->i_size = i_size;
159 ino->i_blksize = i_blksize;
160 ino->i_blocks = i_blocks;
161 return(0);
162 }
163
164 static char *follow_link(char *link)
165 {
166 int len, n;
167 char *name, *resolved, *end;
168
169 len = 64;
170 while(1){
171 n = -ENOMEM;
172 name = kmalloc(len, GFP_KERNEL);
173 if(name == NULL)
174 goto out;
175
176 n = do_readlink(link, name, len);
177 if(n < len)
178 break;
179 len *= 2;
180 kfree(name);
181 }
182 if(n < 0)
183 goto out_free;
184
185 if(*name == '/')
186 return(name);
187
188 end = strrchr(link, '/');
189 if(end == NULL)
190 return(name);
191
192 *(end + 1) = '\0';
193 len = strlen(link) + strlen(name) + 1;
194
195 resolved = kmalloc(len, GFP_KERNEL);
196 if(resolved == NULL){
197 n = -ENOMEM;
198 goto out_free;
199 }
200
201 sprintf(resolved, "%s%s", link, name);
202 kfree(name);
203 kfree(link);
204 return(resolved);
205
206 out_free:
207 kfree(name);
208 out:
209 return(ERR_PTR(n));
210 }
211
212 static int read_inode(struct inode *ino)
213 {
214 char *name;
215 int err = 0;
216
217 /* Unfortunately, we are called from iget() when we don't have a dentry
218 * allocated yet.
219 */
220 if(list_empty(&ino->i_dentry))
221 goto out;
222
223 err = -ENOMEM;
224 name = inode_name(ino, 0);
225 if(name == NULL)
226 goto out;
227
228 if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){
229 name = follow_link(name);
230 if(IS_ERR(name)){
231 err = PTR_ERR(name);
232 goto out;
233 }
234 }
235
236 err = read_name(ino, name);
237 kfree(name);
238 out:
239 return(err);
240 }
241
242 int hostfs_statfs(struct super_block *sb, struct kstatfs *sf)
243 {
244 /* do_statfs uses struct statfs64 internally, but the linux kernel
245 * struct statfs still has 32-bit versions for most of these fields,
246 * so we convert them here
247 */
248 int err;
249 long long f_blocks;
250 long long f_bfree;
251 long long f_bavail;
252 long long f_files;
253 long long f_ffree;
254
255 err = do_statfs(HOSTFS_I(sb->s_root->d_inode)->host_filename,
256 &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
257 &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
258 &sf->f_namelen, sf->f_spare);
259 if(err) return(err);
260 sf->f_blocks = f_blocks;
261 sf->f_bfree = f_bfree;
262 sf->f_bavail = f_bavail;
263 sf->f_files = f_files;
264 sf->f_ffree = f_ffree;
265 sf->f_type = HOSTFS_SUPER_MAGIC;
266 return(0);
267 }
268
269 static struct inode *hostfs_alloc_inode(struct super_block *sb)
270 {
271 struct hostfs_inode_info *hi;
272
273 hi = kmalloc(sizeof(*hi), GFP_KERNEL);
274 if(hi == NULL)
275 return(NULL);
276
277 *hi = ((struct hostfs_inode_info) { .host_filename = NULL,
278 .fd = -1,
279 .mode = 0 });
280 inode_init_once(&hi->vfs_inode);
281 return(&hi->vfs_inode);
282 }
283
284 static void hostfs_delete_inode(struct inode *inode)
285 {
286 truncate_inode_pages(&inode->i_data, 0);
287 if(HOSTFS_I(inode)->fd != -1) {
288 close_file(&HOSTFS_I(inode)->fd);
289 HOSTFS_I(inode)->fd = -1;
290 }
291 clear_inode(inode);
292 }
293
294 static void hostfs_destroy_inode(struct inode *inode)
295 {
296 kfree(HOSTFS_I(inode)->host_filename);
297
298 /*XXX: This should not happen, probably. The check is here for
299 * additional safety.*/
300 if(HOSTFS_I(inode)->fd != -1) {
301 close_file(&HOSTFS_I(inode)->fd);
302 printk(KERN_DEBUG "Closing host fd in .destroy_inode\n");
303 }
304
305 kfree(HOSTFS_I(inode));
306 }
307
308 static void hostfs_read_inode(struct inode *inode)
309 {
310 read_inode(inode);
311 }
312
313 static struct super_operations hostfs_sbops = {
314 .alloc_inode = hostfs_alloc_inode,
315 .drop_inode = generic_delete_inode,
316 .delete_inode = hostfs_delete_inode,
317 .destroy_inode = hostfs_destroy_inode,
318 .read_inode = hostfs_read_inode,
319 .statfs = hostfs_statfs,
320 };
321
322 int hostfs_readdir(struct file *file, void *ent, filldir_t filldir)
323 {
324 void *dir;
325 char *name;
326 unsigned long long next, ino;
327 int error, len;
328
329 name = dentry_name(file->f_dentry, 0);
330 if(name == NULL) return(-ENOMEM);
331 dir = open_dir(name, &error);
332 kfree(name);
333 if(dir == NULL) return(-error);
334 next = file->f_pos;
335 while((name = read_dir(dir, &next, &ino, &len)) != NULL){
336 error = (*filldir)(ent, name, len, file->f_pos,
337 ino, DT_UNKNOWN);
338 if(error) break;
339 file->f_pos = next;
340 }
341 close_dir(dir);
342 return(0);
343 }
344
345 int hostfs_file_open(struct inode *ino, struct file *file)
346 {
347 char *name;
348 int mode = 0, r = 0, w = 0, fd;
349
350 mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
351 if((mode & HOSTFS_I(ino)->mode) == mode)
352 return(0);
353
354 /* The file may already have been opened, but with the wrong access,
355 * so this resets things and reopens the file with the new access.
356 */
357 if(HOSTFS_I(ino)->fd != -1){
358 close_file(&HOSTFS_I(ino)->fd);
359 HOSTFS_I(ino)->fd = -1;
360 }
361
362 HOSTFS_I(ino)->mode |= mode;
363 if(HOSTFS_I(ino)->mode & FMODE_READ)
364 r = 1;
365 if(HOSTFS_I(ino)->mode & FMODE_WRITE)
366 w = 1;
367 if(w)
368 r = 1;
369
370 name = dentry_name(file->f_dentry, 0);
371 if(name == NULL)
372 return(-ENOMEM);
373
374 fd = open_file(name, r, w, append);
375 kfree(name);
376 if(fd < 0) return(fd);
377 FILE_HOSTFS_I(file)->fd = fd;
378
379 return(0);
380 }
381
382 int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync)
383 {
384 return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync);
385 }
386
387 static struct file_operations hostfs_file_fops = {
388 .llseek = generic_file_llseek,
389 .read = generic_file_read,
390 .sendfile = generic_file_sendfile,
391 .aio_read = generic_file_aio_read,
392 .aio_write = generic_file_aio_write,
393 .readv = generic_file_readv,
394 .writev = generic_file_writev,
395 .write = generic_file_write,
396 .mmap = generic_file_mmap,
397 .open = hostfs_file_open,
398 .release = NULL,
399 .fsync = hostfs_fsync,
400 };
401
402 static struct file_operations hostfs_dir_fops = {
403 .llseek = generic_file_llseek,
404 .readdir = hostfs_readdir,
405 .read = generic_read_dir,
406 };
407
408 int hostfs_writepage(struct page *page, struct writeback_control *wbc)
409 {
410 struct address_space *mapping = page->mapping;
411 struct inode *inode = mapping->host;
412 char *buffer;
413 unsigned long long base;
414 int count = PAGE_CACHE_SIZE;
415 int end_index = inode->i_size >> PAGE_CACHE_SHIFT;
416 int err;
417
418 if (page->index >= end_index)
419 count = inode->i_size & (PAGE_CACHE_SIZE-1);
420
421 buffer = kmap(page);
422 base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT;
423
424 err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
425 if(err != count){
426 ClearPageUptodate(page);
427 goto out;
428 }
429
430 if (base > inode->i_size)
431 inode->i_size = base;
432
433 if (PageError(page))
434 ClearPageError(page);
435 err = 0;
436
437 out:
438 kunmap(page);
439
440 unlock_page(page);
441 return err;
442 }
443
444 int hostfs_readpage(struct file *file, struct page *page)
445 {
446 char *buffer;
447 long long start;
448 int err = 0;
449
450 start = (long long) page->index << PAGE_CACHE_SHIFT;
451 buffer = kmap(page);
452 err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
453 PAGE_CACHE_SIZE);
454 if(err < 0) goto out;
455
456 memset(&buffer[err], 0, PAGE_CACHE_SIZE - err);
457
458 flush_dcache_page(page);
459 SetPageUptodate(page);
460 if (PageError(page)) ClearPageError(page);
461 err = 0;
462 out:
463 kunmap(page);
464 unlock_page(page);
465 return(err);
466 }
467
468 int hostfs_prepare_write(struct file *file, struct page *page,
469 unsigned int from, unsigned int to)
470 {
471 char *buffer;
472 long long start, tmp;
473 int err;
474
475 start = (long long) page->index << PAGE_CACHE_SHIFT;
476 buffer = kmap(page);
477 if(from != 0){
478 tmp = start;
479 err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer,
480 from);
481 if(err < 0) goto out;
482 }
483 if(to != PAGE_CACHE_SIZE){
484 start += to;
485 err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to,
486 PAGE_CACHE_SIZE - to);
487 if(err < 0) goto out;
488 }
489 err = 0;
490 out:
491 kunmap(page);
492 return(err);
493 }
494
495 int hostfs_commit_write(struct file *file, struct page *page, unsigned from,
496 unsigned to)
497 {
498 struct address_space *mapping = page->mapping;
499 struct inode *inode = mapping->host;
500 char *buffer;
501 long long start;
502 int err = 0;
503
504 start = (((long long) page->index) << PAGE_CACHE_SHIFT) + from;
505 buffer = kmap(page);
506 err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from,
507 to - from);
508 if(err > 0) err = 0;
509
510 /* Actually, if !err, write_file has added to-from to start, so, despite
511 * the appearance, we are comparing i_size against the _last_ written
512 * location, as we should. */
513
514 if(!err && (start > inode->i_size))
515 inode->i_size = start;
516
517 kunmap(page);
518 return(err);
519 }
520
521 static struct address_space_operations hostfs_aops = {
522 .writepage = hostfs_writepage,
523 .readpage = hostfs_readpage,
524 .set_page_dirty = __set_page_dirty_nobuffers,
525 .prepare_write = hostfs_prepare_write,
526 .commit_write = hostfs_commit_write
527 };
528
529 static int init_inode(struct inode *inode, struct dentry *dentry)
530 {
531 char *name;
532 int type, err = -ENOMEM;
533 int maj, min;
534 dev_t rdev = 0;
535
536 if(dentry){
537 name = dentry_name(dentry, 0);
538 if(name == NULL)
539 goto out;
540 type = file_type(name, &maj, &min);
541 /*Reencode maj and min with the kernel encoding.*/
542 rdev = MKDEV(maj, min);
543 kfree(name);
544 }
545 else type = OS_TYPE_DIR;
546
547 err = 0;
548 if(type == OS_TYPE_SYMLINK)
549 inode->i_op = &page_symlink_inode_operations;
550 else if(type == OS_TYPE_DIR)
551 inode->i_op = &hostfs_dir_iops;
552 else inode->i_op = &hostfs_iops;
553
554 if(type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops;
555 else inode->i_fop = &hostfs_file_fops;
556
557 if(type == OS_TYPE_SYMLINK)
558 inode->i_mapping->a_ops = &hostfs_link_aops;
559 else inode->i_mapping->a_ops = &hostfs_aops;
560
561 switch (type) {
562 case OS_TYPE_CHARDEV:
563 init_special_inode(inode, S_IFCHR, rdev);
564 break;
565 case OS_TYPE_BLOCKDEV:
566 init_special_inode(inode, S_IFBLK, rdev);
567 break;
568 case OS_TYPE_FIFO:
569 init_special_inode(inode, S_IFIFO, 0);
570 break;
571 case OS_TYPE_SOCK:
572 init_special_inode(inode, S_IFSOCK, 0);
573 break;
574 }
575 out:
576 return(err);
577 }
578
579 int hostfs_create(struct inode *dir, struct dentry *dentry, int mode,
580 struct nameidata *nd)
581 {
582 struct inode *inode;
583 char *name;
584 int error, fd;
585
586 error = -ENOMEM;
587 inode = iget(dir->i_sb, 0);
588 if(inode == NULL) goto out;
589
590 error = init_inode(inode, dentry);
591 if(error)
592 goto out_put;
593
594 error = -ENOMEM;
595 name = dentry_name(dentry, 0);
596 if(name == NULL)
597 goto out_put;
598
599 fd = file_create(name,
600 mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR,
601 mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP,
602 mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH);
603 if(fd < 0)
604 error = fd;
605 else error = read_name(inode, name);
606
607 kfree(name);
608 if(error)
609 goto out_put;
610
611 HOSTFS_I(inode)->fd = fd;
612 HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
613 d_instantiate(dentry, inode);
614 return(0);
615
616 out_put:
617 iput(inode);
618 out:
619 return(error);
620 }
621
622 struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
623 struct nameidata *nd)
624 {
625 struct inode *inode;
626 char *name;
627 int err;
628
629 err = -ENOMEM;
630 inode = iget(ino->i_sb, 0);
631 if(inode == NULL)
632 goto out;
633
634 err = init_inode(inode, dentry);
635 if(err)
636 goto out_put;
637
638 err = -ENOMEM;
639 name = dentry_name(dentry, 0);
640 if(name == NULL)
641 goto out_put;
642
643 err = read_name(inode, name);
644 kfree(name);
645 if(err == -ENOENT){
646 iput(inode);
647 inode = NULL;
648 }
649 else if(err)
650 goto out_put;
651
652 d_add(dentry, inode);
653 dentry->d_op = &hostfs_dentry_ops;
654 return(NULL);
655
656 out_put:
657 iput(inode);
658 out:
659 return(ERR_PTR(err));
660 }
661
662 static char *inode_dentry_name(struct inode *ino, struct dentry *dentry)
663 {
664 char *file;
665 int len;
666
667 file = inode_name(ino, dentry->d_name.len + 1);
668 if(file == NULL) return(NULL);
669 strcat(file, "/");
670 len = strlen(file);
671 strncat(file, dentry->d_name.name, dentry->d_name.len);
672 file[len + dentry->d_name.len] = '\0';
673 return(file);
674 }
675
676 int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from)
677 {
678 char *from_name, *to_name;
679 int err;
680
681 if((from_name = inode_dentry_name(ino, from)) == NULL)
682 return(-ENOMEM);
683 to_name = dentry_name(to, 0);
684 if(to_name == NULL){
685 kfree(from_name);
686 return(-ENOMEM);
687 }
688 err = link_file(to_name, from_name);
689 kfree(from_name);
690 kfree(to_name);
691 return(err);
692 }
693
694 int hostfs_unlink(struct inode *ino, struct dentry *dentry)
695 {
696 char *file;
697 int err;
698
699 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
700 if(append)
701 return(-EPERM);
702
703 err = unlink_file(file);
704 kfree(file);
705 return(err);
706 }
707
708 int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to)
709 {
710 char *file;
711 int err;
712
713 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
714 err = make_symlink(file, to);
715 kfree(file);
716 return(err);
717 }
718
719 int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode)
720 {
721 char *file;
722 int err;
723
724 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
725 err = do_mkdir(file, mode);
726 kfree(file);
727 return(err);
728 }
729
730 int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
731 {
732 char *file;
733 int err;
734
735 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
736 err = do_rmdir(file);
737 kfree(file);
738 return(err);
739 }
740
741 int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
742 {
743 struct inode *inode;
744 char *name;
745 int err = -ENOMEM;
746
747 inode = iget(dir->i_sb, 0);
748 if(inode == NULL)
749 goto out;
750
751 err = init_inode(inode, dentry);
752 if(err)
753 goto out_put;
754
755 err = -ENOMEM;
756 name = dentry_name(dentry, 0);
757 if(name == NULL)
758 goto out_put;
759
760 init_special_inode(inode, mode, dev);
761 err = do_mknod(name, mode, dev);
762 if(err)
763 goto out_free;
764
765 err = read_name(inode, name);
766 kfree(name);
767 if(err)
768 goto out_put;
769
770 d_instantiate(dentry, inode);
771 return(0);
772
773 out_free:
774 kfree(name);
775 out_put:
776 iput(inode);
777 out:
778 return(err);
779 }
780
781 int hostfs_rename(struct inode *from_ino, struct dentry *from,
782 struct inode *to_ino, struct dentry *to)
783 {
784 char *from_name, *to_name;
785 int err;
786
787 if((from_name = inode_dentry_name(from_ino, from)) == NULL)
788 return(-ENOMEM);
789 if((to_name = inode_dentry_name(to_ino, to)) == NULL){
790 kfree(from_name);
791 return(-ENOMEM);
792 }
793 err = rename_file(from_name, to_name);
794 kfree(from_name);
795 kfree(to_name);
796 return(err);
797 }
798
799 int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd)
800 {
801 char *name;
802 int r = 0, w = 0, x = 0, err;
803
804 if (desired & MAY_READ) r = 1;
805 if (desired & MAY_WRITE) w = 1;
806 if (desired & MAY_EXEC) x = 1;
807 name = inode_name(ino, 0);
808 if (name == NULL) return(-ENOMEM);
809
810 if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) ||
811 S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode))
812 err = 0;
813 else
814 err = access_file(name, r, w, x);
815 kfree(name);
816 if(!err)
817 err = generic_permission(ino, desired, NULL);
818 return err;
819 }
820
821 int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
822 {
823 struct hostfs_iattr attrs;
824 char *name;
825 int err;
826
827 err = inode_change_ok(dentry->d_inode, attr);
828 if (err)
829 return err;
830
831 if(append)
832 attr->ia_valid &= ~ATTR_SIZE;
833
834 attrs.ia_valid = 0;
835 if(attr->ia_valid & ATTR_MODE){
836 attrs.ia_valid |= HOSTFS_ATTR_MODE;
837 attrs.ia_mode = attr->ia_mode;
838 }
839 if(attr->ia_valid & ATTR_UID){
840 attrs.ia_valid |= HOSTFS_ATTR_UID;
841 attrs.ia_uid = attr->ia_uid;
842 }
843 if(attr->ia_valid & ATTR_GID){
844 attrs.ia_valid |= HOSTFS_ATTR_GID;
845 attrs.ia_gid = attr->ia_gid;
846 }
847 if(attr->ia_valid & ATTR_SIZE){
848 attrs.ia_valid |= HOSTFS_ATTR_SIZE;
849 attrs.ia_size = attr->ia_size;
850 }
851 if(attr->ia_valid & ATTR_ATIME){
852 attrs.ia_valid |= HOSTFS_ATTR_ATIME;
853 attrs.ia_atime = attr->ia_atime;
854 }
855 if(attr->ia_valid & ATTR_MTIME){
856 attrs.ia_valid |= HOSTFS_ATTR_MTIME;
857 attrs.ia_mtime = attr->ia_mtime;
858 }
859 if(attr->ia_valid & ATTR_CTIME){
860 attrs.ia_valid |= HOSTFS_ATTR_CTIME;
861 attrs.ia_ctime = attr->ia_ctime;
862 }
863 if(attr->ia_valid & ATTR_ATIME_SET){
864 attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
865 }
866 if(attr->ia_valid & ATTR_MTIME_SET){
867 attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
868 }
869 name = dentry_name(dentry, 0);
870 if(name == NULL) return(-ENOMEM);
871 err = set_attr(name, &attrs);
872 kfree(name);
873 if(err)
874 return(err);
875
876 return(inode_setattr(dentry->d_inode, attr));
877 }
878
879 int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
880 struct kstat *stat)
881 {
882 generic_fillattr(dentry->d_inode, stat);
883 return(0);
884 }
885
886 static struct inode_operations hostfs_iops = {
887 .create = hostfs_create,
888 .link = hostfs_link,
889 .unlink = hostfs_unlink,
890 .symlink = hostfs_symlink,
891 .mkdir = hostfs_mkdir,
892 .rmdir = hostfs_rmdir,
893 .mknod = hostfs_mknod,
894 .rename = hostfs_rename,
895 .permission = hostfs_permission,
896 .setattr = hostfs_setattr,
897 .getattr = hostfs_getattr,
898 };
899
900 static struct inode_operations hostfs_dir_iops = {
901 .create = hostfs_create,
902 .lookup = hostfs_lookup,
903 .link = hostfs_link,
904 .unlink = hostfs_unlink,
905 .symlink = hostfs_symlink,
906 .mkdir = hostfs_mkdir,
907 .rmdir = hostfs_rmdir,
908 .mknod = hostfs_mknod,
909 .rename = hostfs_rename,
910 .permission = hostfs_permission,
911 .setattr = hostfs_setattr,
912 .getattr = hostfs_getattr,
913 };
914
915 int hostfs_link_readpage(struct file *file, struct page *page)
916 {
917 char *buffer, *name;
918 int err;
919
920 buffer = kmap(page);
921 name = inode_name(page->mapping->host, 0);
922 if(name == NULL) return(-ENOMEM);
923 err = do_readlink(name, buffer, PAGE_CACHE_SIZE);
924 kfree(name);
925 if(err == PAGE_CACHE_SIZE)
926 err = -E2BIG;
927 else if(err > 0){
928 flush_dcache_page(page);
929 SetPageUptodate(page);
930 if (PageError(page)) ClearPageError(page);
931 err = 0;
932 }
933 kunmap(page);
934 unlock_page(page);
935 return(err);
936 }
937
938 static struct address_space_operations hostfs_link_aops = {
939 .readpage = hostfs_link_readpage,
940 };
941
942 static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
943 {
944 struct inode *root_inode;
945 char *name, *data = d;
946 int err;
947
948 sb->s_blocksize = 1024;
949 sb->s_blocksize_bits = 10;
950 sb->s_magic = HOSTFS_SUPER_MAGIC;
951 sb->s_op = &hostfs_sbops;
952
953 if((data == NULL) || (*data == '\0'))
954 data = root_ino;
955
956 err = -ENOMEM;
957 name = kmalloc(strlen(data) + 1, GFP_KERNEL);
958 if(name == NULL)
959 goto out;
960
961 strcpy(name, data);
962
963 root_inode = iget(sb, 0);
964 if(root_inode == NULL)
965 goto out_free;
966
967 err = init_inode(root_inode, NULL);
968 if(err)
969 goto out_put;
970
971 HOSTFS_I(root_inode)->host_filename = name;
972
973 err = -ENOMEM;
974 sb->s_root = d_alloc_root(root_inode);
975 if(sb->s_root == NULL)
976 goto out_put;
977
978 err = read_inode(root_inode);
979 if(err){
980 /* No iput in this case because the dput does that for us */
981 dput(sb->s_root);
982 sb->s_root = NULL;
983 goto out_free;
984 }
985
986 return(0);
987
988 out_put:
989 iput(root_inode);
990 out_free:
991 kfree(name);
992 out:
993 return(err);
994 }
995
996 static struct super_block *hostfs_read_sb(struct file_system_type *type,
997 int flags, const char *dev_name,
998 void *data)
999 {
1000 return(get_sb_nodev(type, flags, data, hostfs_fill_sb_common));
1001 }
1002
1003 static struct file_system_type hostfs_type = {
1004 .owner = THIS_MODULE,
1005 .name = "hostfs",
1006 .get_sb = hostfs_read_sb,
1007 .kill_sb = kill_anon_super,
1008 .fs_flags = 0,
1009 };
1010
1011 static int __init init_hostfs(void)
1012 {
1013 return(register_filesystem(&hostfs_type));
1014 }
1015
1016 static void __exit exit_hostfs(void)
1017 {
1018 unregister_filesystem(&hostfs_type);
1019 }
1020
1021 module_init(init_hostfs)
1022 module_exit(exit_hostfs)
1023 MODULE_LICENSE("GPL");
1024
1025 /*
1026 * Overrides for Emacs so that we follow Linus's tabbing style.
1027 * Emacs will notice this stuff at the end of the file and automatically
1028 * adjust the settings for this buffer only. This must remain at the end
1029 * of the file.
1030 * ---------------------------------------------------------------------------
1031 * Local variables:
1032 * c-file-style: "linux"
1033 * End:
1034 */
kernel source for telekom puls (alcatel/mediatek)