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[PATCH] uml: hostfs: make hostfs= option work as a jail, as intended.
[linux-2.6/linux-mips.git] / fs / hostfs / hostfs_kern.c
blob9baf69773ed119c2144bdb228ea592a715cec1f5
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_path.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 const struct inode_operations hostfs_iops;
56 static const struct inode_operations hostfs_dir_iops;
57 static const 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_blocks = i_blocks;
160 return(0);
161 }
162
163 static char *follow_link(char *link)
164 {
165 int len, n;
166 char *name, *resolved, *end;
167
168 len = 64;
169 while(1){
170 n = -ENOMEM;
171 name = kmalloc(len, GFP_KERNEL);
172 if(name == NULL)
173 goto out;
174
175 n = do_readlink(link, name, len);
176 if(n < len)
177 break;
178 len *= 2;
179 kfree(name);
180 }
181 if(n < 0)
182 goto out_free;
183
184 if(*name == '/')
185 return(name);
186
187 end = strrchr(link, '/');
188 if(end == NULL)
189 return(name);
190
191 *(end + 1) = '\0';
192 len = strlen(link) + strlen(name) + 1;
193
194 resolved = kmalloc(len, GFP_KERNEL);
195 if(resolved == NULL){
196 n = -ENOMEM;
197 goto out_free;
198 }
199
200 sprintf(resolved, "%s%s", link, name);
201 kfree(name);
202 kfree(link);
203 return(resolved);
204
205 out_free:
206 kfree(name);
207 out:
208 return(ERR_PTR(n));
209 }
210
211 static int read_inode(struct inode *ino)
212 {
213 char *name;
214 int err = 0;
215
216 /* Unfortunately, we are called from iget() when we don't have a dentry
217 * allocated yet.
218 */
219 if(list_empty(&ino->i_dentry))
220 goto out;
221
222 err = -ENOMEM;
223 name = inode_name(ino, 0);
224 if(name == NULL)
225 goto out;
226
227 if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){
228 name = follow_link(name);
229 if(IS_ERR(name)){
230 err = PTR_ERR(name);
231 goto out;
232 }
233 }
234
235 err = read_name(ino, name);
236 kfree(name);
237 out:
238 return(err);
239 }
240
241 int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
242 {
243 /* do_statfs uses struct statfs64 internally, but the linux kernel
244 * struct statfs still has 32-bit versions for most of these fields,
245 * so we convert them here
246 */
247 int err;
248 long long f_blocks;
249 long long f_bfree;
250 long long f_bavail;
251 long long f_files;
252 long long f_ffree;
253
254 err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename,
255 &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
256 &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
257 &sf->f_namelen, sf->f_spare);
258 if(err) return(err);
259 sf->f_blocks = f_blocks;
260 sf->f_bfree = f_bfree;
261 sf->f_bavail = f_bavail;
262 sf->f_files = f_files;
263 sf->f_ffree = f_ffree;
264 sf->f_type = HOSTFS_SUPER_MAGIC;
265 return(0);
266 }
267
268 static struct inode *hostfs_alloc_inode(struct super_block *sb)
269 {
270 struct hostfs_inode_info *hi;
271
272 hi = kmalloc(sizeof(*hi), GFP_KERNEL);
273 if(hi == NULL)
274 return(NULL);
275
276 *hi = ((struct hostfs_inode_info) { .host_filename = NULL,
277 .fd = -1,
278 .mode = 0 });
279 inode_init_once(&hi->vfs_inode);
280 return(&hi->vfs_inode);
281 }
282
283 static void hostfs_delete_inode(struct inode *inode)
284 {
285 truncate_inode_pages(&inode->i_data, 0);
286 if(HOSTFS_I(inode)->fd != -1) {
287 close_file(&HOSTFS_I(inode)->fd);
288 HOSTFS_I(inode)->fd = -1;
289 }
290 clear_inode(inode);
291 }
292
293 static void hostfs_destroy_inode(struct inode *inode)
294 {
295 kfree(HOSTFS_I(inode)->host_filename);
296
297 /*XXX: This should not happen, probably. The check is here for
298 * additional safety.*/
299 if(HOSTFS_I(inode)->fd != -1) {
300 close_file(&HOSTFS_I(inode)->fd);
301 printk(KERN_DEBUG "Closing host fd in .destroy_inode\n");
302 }
303
304 kfree(HOSTFS_I(inode));
305 }
306
307 static void hostfs_read_inode(struct inode *inode)
308 {
309 read_inode(inode);
310 }
311
312 static const struct super_operations hostfs_sbops = {
313 .alloc_inode = hostfs_alloc_inode,
314 .drop_inode = generic_delete_inode,
315 .delete_inode = hostfs_delete_inode,
316 .destroy_inode = hostfs_destroy_inode,
317 .read_inode = hostfs_read_inode,
318 .statfs = hostfs_statfs,
319 };
320
321 int hostfs_readdir(struct file *file, void *ent, filldir_t filldir)
322 {
323 void *dir;
324 char *name;
325 unsigned long long next, ino;
326 int error, len;
327
328 name = dentry_name(file->f_path.dentry, 0);
329 if(name == NULL) return(-ENOMEM);
330 dir = open_dir(name, &error);
331 kfree(name);
332 if(dir == NULL) return(-error);
333 next = file->f_pos;
334 while((name = read_dir(dir, &next, &ino, &len)) != NULL){
335 error = (*filldir)(ent, name, len, file->f_pos,
336 ino, DT_UNKNOWN);
337 if(error) break;
338 file->f_pos = next;
339 }
340 close_dir(dir);
341 return(0);
342 }
343
344 int hostfs_file_open(struct inode *ino, struct file *file)
345 {
346 char *name;
347 int mode = 0, r = 0, w = 0, fd;
348
349 mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
350 if((mode & HOSTFS_I(ino)->mode) == mode)
351 return(0);
352
353 /* The file may already have been opened, but with the wrong access,
354 * so this resets things and reopens the file with the new access.
355 */
356 if(HOSTFS_I(ino)->fd != -1){
357 close_file(&HOSTFS_I(ino)->fd);
358 HOSTFS_I(ino)->fd = -1;
359 }
360
361 HOSTFS_I(ino)->mode |= mode;
362 if(HOSTFS_I(ino)->mode & FMODE_READ)
363 r = 1;
364 if(HOSTFS_I(ino)->mode & FMODE_WRITE)
365 w = 1;
366 if(w)
367 r = 1;
368
369 name = dentry_name(file->f_path.dentry, 0);
370 if(name == NULL)
371 return(-ENOMEM);
372
373 fd = open_file(name, r, w, append);
374 kfree(name);
375 if(fd < 0) return(fd);
376 FILE_HOSTFS_I(file)->fd = fd;
377
378 return(0);
379 }
380
381 int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync)
382 {
383 return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync);
384 }
385
386 static const struct file_operations hostfs_file_fops = {
387 .llseek = generic_file_llseek,
388 .read = do_sync_read,
389 .sendfile = generic_file_sendfile,
390 .aio_read = generic_file_aio_read,
391 .aio_write = generic_file_aio_write,
392 .write = do_sync_write,
393 .mmap = generic_file_mmap,
394 .open = hostfs_file_open,
395 .release = NULL,
396 .fsync = hostfs_fsync,
397 };
398
399 static const struct file_operations hostfs_dir_fops = {
400 .llseek = generic_file_llseek,
401 .readdir = hostfs_readdir,
402 .read = generic_read_dir,
403 };
404
405 int hostfs_writepage(struct page *page, struct writeback_control *wbc)
406 {
407 struct address_space *mapping = page->mapping;
408 struct inode *inode = mapping->host;
409 char *buffer;
410 unsigned long long base;
411 int count = PAGE_CACHE_SIZE;
412 int end_index = inode->i_size >> PAGE_CACHE_SHIFT;
413 int err;
414
415 if (page->index >= end_index)
416 count = inode->i_size & (PAGE_CACHE_SIZE-1);
417
418 buffer = kmap(page);
419 base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT;
420
421 err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
422 if(err != count){
423 ClearPageUptodate(page);
424 goto out;
425 }
426
427 if (base > inode->i_size)
428 inode->i_size = base;
429
430 if (PageError(page))
431 ClearPageError(page);
432 err = 0;
433
434 out:
435 kunmap(page);
436
437 unlock_page(page);
438 return err;
439 }
440
441 int hostfs_readpage(struct file *file, struct page *page)
442 {
443 char *buffer;
444 long long start;
445 int err = 0;
446
447 start = (long long) page->index << PAGE_CACHE_SHIFT;
448 buffer = kmap(page);
449 err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
450 PAGE_CACHE_SIZE);
451 if(err < 0) goto out;
452
453 memset(&buffer[err], 0, PAGE_CACHE_SIZE - err);
454
455 flush_dcache_page(page);
456 SetPageUptodate(page);
457 if (PageError(page)) ClearPageError(page);
458 err = 0;
459 out:
460 kunmap(page);
461 unlock_page(page);
462 return(err);
463 }
464
465 int hostfs_prepare_write(struct file *file, struct page *page,
466 unsigned int from, unsigned int to)
467 {
468 char *buffer;
469 long long start, tmp;
470 int err;
471
472 start = (long long) page->index << PAGE_CACHE_SHIFT;
473 buffer = kmap(page);
474 if(from != 0){
475 tmp = start;
476 err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer,
477 from);
478 if(err < 0) goto out;
479 }
480 if(to != PAGE_CACHE_SIZE){
481 start += to;
482 err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to,
483 PAGE_CACHE_SIZE - to);
484 if(err < 0) goto out;
485 }
486 err = 0;
487 out:
488 kunmap(page);
489 return(err);
490 }
491
492 int hostfs_commit_write(struct file *file, struct page *page, unsigned from,
493 unsigned to)
494 {
495 struct address_space *mapping = page->mapping;
496 struct inode *inode = mapping->host;
497 char *buffer;
498 long long start;
499 int err = 0;
500
501 start = (((long long) page->index) << PAGE_CACHE_SHIFT) + from;
502 buffer = kmap(page);
503 err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from,
504 to - from);
505 if(err > 0) err = 0;
506
507 /* Actually, if !err, write_file has added to-from to start, so, despite
508 * the appearance, we are comparing i_size against the _last_ written
509 * location, as we should. */
510
511 if(!err && (start > inode->i_size))
512 inode->i_size = start;
513
514 kunmap(page);
515 return(err);
516 }
517
518 static const struct address_space_operations hostfs_aops = {
519 .writepage = hostfs_writepage,
520 .readpage = hostfs_readpage,
521 .set_page_dirty = __set_page_dirty_nobuffers,
522 .prepare_write = hostfs_prepare_write,
523 .commit_write = hostfs_commit_write
524 };
525
526 static int init_inode(struct inode *inode, struct dentry *dentry)
527 {
528 char *name;
529 int type, err = -ENOMEM;
530 int maj, min;
531 dev_t rdev = 0;
532
533 if(dentry){
534 name = dentry_name(dentry, 0);
535 if(name == NULL)
536 goto out;
537 type = file_type(name, &maj, &min);
538 /*Reencode maj and min with the kernel encoding.*/
539 rdev = MKDEV(maj, min);
540 kfree(name);
541 }
542 else type = OS_TYPE_DIR;
543
544 err = 0;
545 if(type == OS_TYPE_SYMLINK)
546 inode->i_op = &page_symlink_inode_operations;
547 else if(type == OS_TYPE_DIR)
548 inode->i_op = &hostfs_dir_iops;
549 else inode->i_op = &hostfs_iops;
550
551 if(type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops;
552 else inode->i_fop = &hostfs_file_fops;
553
554 if(type == OS_TYPE_SYMLINK)
555 inode->i_mapping->a_ops = &hostfs_link_aops;
556 else inode->i_mapping->a_ops = &hostfs_aops;
557
558 switch (type) {
559 case OS_TYPE_CHARDEV:
560 init_special_inode(inode, S_IFCHR, rdev);
561 break;
562 case OS_TYPE_BLOCKDEV:
563 init_special_inode(inode, S_IFBLK, rdev);
564 break;
565 case OS_TYPE_FIFO:
566 init_special_inode(inode, S_IFIFO, 0);
567 break;
568 case OS_TYPE_SOCK:
569 init_special_inode(inode, S_IFSOCK, 0);
570 break;
571 }
572 out:
573 return(err);
574 }
575
576 int hostfs_create(struct inode *dir, struct dentry *dentry, int mode,
577 struct nameidata *nd)
578 {
579 struct inode *inode;
580 char *name;
581 int error, fd;
582
583 error = -ENOMEM;
584 inode = iget(dir->i_sb, 0);
585 if(inode == NULL) goto out;
586
587 error = init_inode(inode, dentry);
588 if(error)
589 goto out_put;
590
591 error = -ENOMEM;
592 name = dentry_name(dentry, 0);
593 if(name == NULL)
594 goto out_put;
595
596 fd = file_create(name,
597 mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR,
598 mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP,
599 mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH);
600 if(fd < 0)
601 error = fd;
602 else error = read_name(inode, name);
603
604 kfree(name);
605 if(error)
606 goto out_put;
607
608 HOSTFS_I(inode)->fd = fd;
609 HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
610 d_instantiate(dentry, inode);
611 return(0);
612
613 out_put:
614 iput(inode);
615 out:
616 return(error);
617 }
618
619 struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
620 struct nameidata *nd)
621 {
622 struct inode *inode;
623 char *name;
624 int err;
625
626 err = -ENOMEM;
627 inode = iget(ino->i_sb, 0);
628 if(inode == NULL)
629 goto out;
630
631 err = init_inode(inode, dentry);
632 if(err)
633 goto out_put;
634
635 err = -ENOMEM;
636 name = dentry_name(dentry, 0);
637 if(name == NULL)
638 goto out_put;
639
640 err = read_name(inode, name);
641 kfree(name);
642 if(err == -ENOENT){
643 iput(inode);
644 inode = NULL;
645 }
646 else if(err)
647 goto out_put;
648
649 d_add(dentry, inode);
650 dentry->d_op = &hostfs_dentry_ops;
651 return(NULL);
652
653 out_put:
654 iput(inode);
655 out:
656 return(ERR_PTR(err));
657 }
658
659 static char *inode_dentry_name(struct inode *ino, struct dentry *dentry)
660 {
661 char *file;
662 int len;
663
664 file = inode_name(ino, dentry->d_name.len + 1);
665 if(file == NULL) return(NULL);
666 strcat(file, "/");
667 len = strlen(file);
668 strncat(file, dentry->d_name.name, dentry->d_name.len);
669 file[len + dentry->d_name.len] = '\0';
670 return(file);
671 }
672
673 int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from)
674 {
675 char *from_name, *to_name;
676 int err;
677
678 if((from_name = inode_dentry_name(ino, from)) == NULL)
679 return(-ENOMEM);
680 to_name = dentry_name(to, 0);
681 if(to_name == NULL){
682 kfree(from_name);
683 return(-ENOMEM);
684 }
685 err = link_file(to_name, from_name);
686 kfree(from_name);
687 kfree(to_name);
688 return(err);
689 }
690
691 int hostfs_unlink(struct inode *ino, struct dentry *dentry)
692 {
693 char *file;
694 int err;
695
696 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
697 if(append)
698 return(-EPERM);
699
700 err = unlink_file(file);
701 kfree(file);
702 return(err);
703 }
704
705 int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to)
706 {
707 char *file;
708 int err;
709
710 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
711 err = make_symlink(file, to);
712 kfree(file);
713 return(err);
714 }
715
716 int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode)
717 {
718 char *file;
719 int err;
720
721 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
722 err = do_mkdir(file, mode);
723 kfree(file);
724 return(err);
725 }
726
727 int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
728 {
729 char *file;
730 int err;
731
732 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
733 err = do_rmdir(file);
734 kfree(file);
735 return(err);
736 }
737
738 int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
739 {
740 struct inode *inode;
741 char *name;
742 int err = -ENOMEM;
743
744 inode = iget(dir->i_sb, 0);
745 if(inode == NULL)
746 goto out;
747
748 err = init_inode(inode, dentry);
749 if(err)
750 goto out_put;
751
752 err = -ENOMEM;
753 name = dentry_name(dentry, 0);
754 if(name == NULL)
755 goto out_put;
756
757 init_special_inode(inode, mode, dev);
758 err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
759 if(err)
760 goto out_free;
761
762 err = read_name(inode, name);
763 kfree(name);
764 if(err)
765 goto out_put;
766
767 d_instantiate(dentry, inode);
768 return(0);
769
770 out_free:
771 kfree(name);
772 out_put:
773 iput(inode);
774 out:
775 return(err);
776 }
777
778 int hostfs_rename(struct inode *from_ino, struct dentry *from,
779 struct inode *to_ino, struct dentry *to)
780 {
781 char *from_name, *to_name;
782 int err;
783
784 if((from_name = inode_dentry_name(from_ino, from)) == NULL)
785 return(-ENOMEM);
786 if((to_name = inode_dentry_name(to_ino, to)) == NULL){
787 kfree(from_name);
788 return(-ENOMEM);
789 }
790 err = rename_file(from_name, to_name);
791 kfree(from_name);
792 kfree(to_name);
793 return(err);
794 }
795
796 int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd)
797 {
798 char *name;
799 int r = 0, w = 0, x = 0, err;
800
801 if (desired & MAY_READ) r = 1;
802 if (desired & MAY_WRITE) w = 1;
803 if (desired & MAY_EXEC) x = 1;
804 name = inode_name(ino, 0);
805 if (name == NULL) return(-ENOMEM);
806
807 if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) ||
808 S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode))
809 err = 0;
810 else
811 err = access_file(name, r, w, x);
812 kfree(name);
813 if(!err)
814 err = generic_permission(ino, desired, NULL);
815 return err;
816 }
817
818 int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
819 {
820 struct hostfs_iattr attrs;
821 char *name;
822 int err;
823
824 err = inode_change_ok(dentry->d_inode, attr);
825 if (err)
826 return err;
827
828 if(append)
829 attr->ia_valid &= ~ATTR_SIZE;
830
831 attrs.ia_valid = 0;
832 if(attr->ia_valid & ATTR_MODE){
833 attrs.ia_valid |= HOSTFS_ATTR_MODE;
834 attrs.ia_mode = attr->ia_mode;
835 }
836 if(attr->ia_valid & ATTR_UID){
837 attrs.ia_valid |= HOSTFS_ATTR_UID;
838 attrs.ia_uid = attr->ia_uid;
839 }
840 if(attr->ia_valid & ATTR_GID){
841 attrs.ia_valid |= HOSTFS_ATTR_GID;
842 attrs.ia_gid = attr->ia_gid;
843 }
844 if(attr->ia_valid & ATTR_SIZE){
845 attrs.ia_valid |= HOSTFS_ATTR_SIZE;
846 attrs.ia_size = attr->ia_size;
847 }
848 if(attr->ia_valid & ATTR_ATIME){
849 attrs.ia_valid |= HOSTFS_ATTR_ATIME;
850 attrs.ia_atime = attr->ia_atime;
851 }
852 if(attr->ia_valid & ATTR_MTIME){
853 attrs.ia_valid |= HOSTFS_ATTR_MTIME;
854 attrs.ia_mtime = attr->ia_mtime;
855 }
856 if(attr->ia_valid & ATTR_CTIME){
857 attrs.ia_valid |= HOSTFS_ATTR_CTIME;
858 attrs.ia_ctime = attr->ia_ctime;
859 }
860 if(attr->ia_valid & ATTR_ATIME_SET){
861 attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
862 }
863 if(attr->ia_valid & ATTR_MTIME_SET){
864 attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
865 }
866 name = dentry_name(dentry, 0);
867 if(name == NULL) return(-ENOMEM);
868 err = set_attr(name, &attrs);
869 kfree(name);
870 if(err)
871 return(err);
872
873 return(inode_setattr(dentry->d_inode, attr));
874 }
875
876 int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
877 struct kstat *stat)
878 {
879 generic_fillattr(dentry->d_inode, stat);
880 return(0);
881 }
882
883 static const struct inode_operations hostfs_iops = {
884 .create = hostfs_create,
885 .link = hostfs_link,
886 .unlink = hostfs_unlink,
887 .symlink = hostfs_symlink,
888 .mkdir = hostfs_mkdir,
889 .rmdir = hostfs_rmdir,
890 .mknod = hostfs_mknod,
891 .rename = hostfs_rename,
892 .permission = hostfs_permission,
893 .setattr = hostfs_setattr,
894 .getattr = hostfs_getattr,
895 };
896
897 static const struct inode_operations hostfs_dir_iops = {
898 .create = hostfs_create,
899 .lookup = hostfs_lookup,
900 .link = hostfs_link,
901 .unlink = hostfs_unlink,
902 .symlink = hostfs_symlink,
903 .mkdir = hostfs_mkdir,
904 .rmdir = hostfs_rmdir,
905 .mknod = hostfs_mknod,
906 .rename = hostfs_rename,
907 .permission = hostfs_permission,
908 .setattr = hostfs_setattr,
909 .getattr = hostfs_getattr,
910 };
911
912 int hostfs_link_readpage(struct file *file, struct page *page)
913 {
914 char *buffer, *name;
915 int err;
916
917 buffer = kmap(page);
918 name = inode_name(page->mapping->host, 0);
919 if(name == NULL) return(-ENOMEM);
920 err = do_readlink(name, buffer, PAGE_CACHE_SIZE);
921 kfree(name);
922 if(err == PAGE_CACHE_SIZE)
923 err = -E2BIG;
924 else if(err > 0){
925 flush_dcache_page(page);
926 SetPageUptodate(page);
927 if (PageError(page)) ClearPageError(page);
928 err = 0;
929 }
930 kunmap(page);
931 unlock_page(page);
932 return(err);
933 }
934
935 static const struct address_space_operations hostfs_link_aops = {
936 .readpage = hostfs_link_readpage,
937 };
938
939 static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
940 {
941 struct inode *root_inode;
942 char *name, *data = d;
943 int err;
944
945 sb->s_blocksize = 1024;
946 sb->s_blocksize_bits = 10;
947 sb->s_magic = HOSTFS_SUPER_MAGIC;
948 sb->s_op = &hostfs_sbops;
949
950 /* NULL is printed as <NULL> by sprintf: avoid that. */
951 if (data == NULL)
952 data = "";
953
954 err = -ENOMEM;
955 name = kmalloc(strlen(root_ino) + 1
956 + strlen(data) + 1, GFP_KERNEL);
957 if(name == NULL)
958 goto out;
959
960 sprintf(name, "%s/%s", root_ino, data);
961
962 root_inode = iget(sb, 0);
963 if(root_inode == NULL)
964 goto out_free;
965
966 err = init_inode(root_inode, NULL);
967 if(err)
968 goto out_put;
969
970 HOSTFS_I(root_inode)->host_filename = name;
971 /* Avoid that in the error path, iput(root_inode) frees again name through
972 * hostfs_destroy_inode! */
973 name = NULL;
974
975 err = -ENOMEM;
976 sb->s_root = d_alloc_root(root_inode);
977 if(sb->s_root == NULL)
978 goto out_put;
979
980 err = read_inode(root_inode);
981 if(err){
982 /* No iput in this case because the dput does that for us */
983 dput(sb->s_root);
984 sb->s_root = NULL;
985 goto out;
986 }
987
988 return(0);
989
990 out_put:
991 iput(root_inode);
992 out_free:
993 kfree(name);
994 out:
995 return(err);
996 }
997
998 static int hostfs_read_sb(struct file_system_type *type,
999 int flags, const char *dev_name,
1000 void *data, struct vfsmount *mnt)
1001 {
1002 return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt);
1003 }
1004
1005 static struct file_system_type hostfs_type = {
1006 .owner = THIS_MODULE,
1007 .name = "hostfs",
1008 .get_sb = hostfs_read_sb,
1009 .kill_sb = kill_anon_super,
1010 .fs_flags = 0,
1011 };
1012
1013 static int __init init_hostfs(void)
1014 {
1015 return(register_filesystem(&hostfs_type));
1016 }
1017
1018 static void __exit exit_hostfs(void)
1019 {
1020 unregister_filesystem(&hostfs_type);
1021 }
1022
1023 module_init(init_hostfs)
1024 module_exit(exit_hostfs)
1025 MODULE_LICENSE("GPL");
1026
1027 /*
1028 * Overrides for Emacs so that we follow Linus's tabbing style.
1029 * Emacs will notice this stuff at the end of the file and automatically
1030 * adjust the settings for this buffer only. This must remain at the end
1031 * of the file.
1032 * ---------------------------------------------------------------------------
1033 * Local variables:
1034 * c-file-style: "linux"
1035 * End:
1036 */
Mirror of the linux-mips.org kernel tree