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1da177e4 LT |
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/version.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/pagemap.h> | |
16 | #include <linux/blkdev.h> | |
17 | #include <linux/list.h> | |
1da177e4 LT |
18 | #include <linux/statfs.h> |
19 | #include <linux/kdev_t.h> | |
20 | #include <asm/uaccess.h> | |
21 | #include "hostfs.h" | |
22 | #include "kern_util.h" | |
23 | #include "kern.h" | |
24 | #include "user_util.h" | |
1da177e4 LT |
25 | #include "init.h" |
26 | ||
27 | struct hostfs_inode_info { | |
28 | char *host_filename; | |
29 | int fd; | |
30 | int mode; | |
31 | struct inode vfs_inode; | |
32 | }; | |
33 | ||
34 | static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) | |
35 | { | |
36 | return(list_entry(inode, struct hostfs_inode_info, vfs_inode)); | |
37 | } | |
38 | ||
39 | #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_dentry->d_inode) | |
40 | ||
41 | int hostfs_d_delete(struct dentry *dentry) | |
42 | { | |
43 | return(1); | |
44 | } | |
45 | ||
46 | struct dentry_operations hostfs_dentry_ops = { | |
47 | .d_delete = hostfs_d_delete, | |
48 | }; | |
49 | ||
50 | /* Changed in hostfs_args before the kernel starts running */ | |
51 | static char *root_ino = "/"; | |
52 | static int append = 0; | |
53 | ||
54 | #define HOSTFS_SUPER_MAGIC 0x00c0ffee | |
55 | ||
56 | static struct inode_operations hostfs_iops; | |
57 | static struct inode_operations hostfs_dir_iops; | |
58 | static struct address_space_operations hostfs_link_aops; | |
59 | ||
60 | #ifndef MODULE | |
61 | static int __init hostfs_args(char *options, int *add) | |
62 | { | |
63 | char *ptr; | |
64 | ||
65 | ptr = strchr(options, ','); | |
66 | if(ptr != NULL) | |
67 | *ptr++ = '\0'; | |
68 | if(*options != '\0') | |
69 | root_ino = options; | |
70 | ||
71 | options = ptr; | |
72 | while(options){ | |
73 | ptr = strchr(options, ','); | |
74 | if(ptr != NULL) | |
75 | *ptr++ = '\0'; | |
76 | if(*options != '\0'){ | |
77 | if(!strcmp(options, "append")) | |
78 | append = 1; | |
79 | else printf("hostfs_args - unsupported option - %s\n", | |
80 | options); | |
81 | } | |
82 | options = ptr; | |
83 | } | |
84 | return(0); | |
85 | } | |
86 | ||
87 | __uml_setup("hostfs=", hostfs_args, | |
88 | "hostfs=<root dir>,<flags>,...\n" | |
89 | " This is used to set hostfs parameters. The root directory argument\n" | |
90 | " is used to confine all hostfs mounts to within the specified directory\n" | |
91 | " tree on the host. If this isn't specified, then a user inside UML can\n" | |
92 | " mount anything on the host that's accessible to the user that's running\n" | |
93 | " it.\n" | |
94 | " The only flag currently supported is 'append', which specifies that all\n" | |
95 | " files opened by hostfs will be opened in append mode.\n\n" | |
96 | ); | |
97 | #endif | |
98 | ||
99 | static char *dentry_name(struct dentry *dentry, int extra) | |
100 | { | |
101 | struct dentry *parent; | |
102 | char *root, *name; | |
103 | int len; | |
104 | ||
105 | len = 0; | |
106 | parent = dentry; | |
107 | while(parent->d_parent != parent){ | |
108 | len += parent->d_name.len + 1; | |
109 | parent = parent->d_parent; | |
110 | } | |
111 | ||
112 | root = HOSTFS_I(parent->d_inode)->host_filename; | |
113 | len += strlen(root); | |
114 | name = kmalloc(len + extra + 1, GFP_KERNEL); | |
115 | if(name == NULL) return(NULL); | |
116 | ||
117 | name[len] = '\0'; | |
118 | parent = dentry; | |
119 | while(parent->d_parent != parent){ | |
120 | len -= parent->d_name.len + 1; | |
121 | name[len] = '/'; | |
122 | strncpy(&name[len + 1], parent->d_name.name, | |
123 | parent->d_name.len); | |
124 | parent = parent->d_parent; | |
125 | } | |
126 | strncpy(name, root, strlen(root)); | |
127 | return(name); | |
128 | } | |
129 | ||
130 | static char *inode_name(struct inode *ino, int extra) | |
131 | { | |
132 | struct dentry *dentry; | |
133 | ||
134 | dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); | |
135 | return(dentry_name(dentry, extra)); | |
136 | } | |
137 | ||
138 | static int read_name(struct inode *ino, char *name) | |
139 | { | |
140 | /* The non-int inode fields are copied into ints by stat_file and | |
141 | * then copied into the inode because passing the actual pointers | |
142 | * in and having them treated as int * breaks on big-endian machines | |
143 | */ | |
144 | int err; | |
145 | int i_mode, i_nlink, i_blksize; | |
146 | unsigned long long i_size; | |
147 | unsigned long long i_ino; | |
148 | unsigned long long i_blocks; | |
149 | ||
150 | err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, | |
151 | &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, | |
152 | &ino->i_ctime, &i_blksize, &i_blocks); | |
153 | if(err) | |
154 | return(err); | |
155 | ||
156 | ino->i_ino = i_ino; | |
157 | ino->i_mode = i_mode; | |
158 | ino->i_nlink = i_nlink; | |
159 | ino->i_size = i_size; | |
160 | ino->i_blksize = i_blksize; | |
161 | ino->i_blocks = i_blocks; | |
1da177e4 LT |
162 | return(0); |
163 | } | |
164 | ||
165 | static char *follow_link(char *link) | |
166 | { | |
167 | int len, n; | |
168 | char *name, *resolved, *end; | |
169 | ||
170 | len = 64; | |
171 | while(1){ | |
172 | n = -ENOMEM; | |
173 | name = kmalloc(len, GFP_KERNEL); | |
174 | if(name == NULL) | |
175 | goto out; | |
176 | ||
177 | n = do_readlink(link, name, len); | |
178 | if(n < len) | |
179 | break; | |
180 | len *= 2; | |
181 | kfree(name); | |
182 | } | |
183 | if(n < 0) | |
184 | goto out_free; | |
185 | ||
186 | if(*name == '/') | |
187 | return(name); | |
188 | ||
189 | end = strrchr(link, '/'); | |
190 | if(end == NULL) | |
191 | return(name); | |
192 | ||
193 | *(end + 1) = '\0'; | |
194 | len = strlen(link) + strlen(name) + 1; | |
195 | ||
196 | resolved = kmalloc(len, GFP_KERNEL); | |
197 | if(resolved == NULL){ | |
198 | n = -ENOMEM; | |
199 | goto out_free; | |
200 | } | |
201 | ||
202 | sprintf(resolved, "%s%s", link, name); | |
203 | kfree(name); | |
204 | kfree(link); | |
205 | return(resolved); | |
206 | ||
207 | out_free: | |
208 | kfree(name); | |
209 | out: | |
210 | return(ERR_PTR(n)); | |
211 | } | |
212 | ||
213 | static int read_inode(struct inode *ino) | |
214 | { | |
215 | char *name; | |
216 | int err = 0; | |
217 | ||
218 | /* Unfortunately, we are called from iget() when we don't have a dentry | |
219 | * allocated yet. | |
220 | */ | |
221 | if(list_empty(&ino->i_dentry)) | |
222 | goto out; | |
223 | ||
224 | err = -ENOMEM; | |
225 | name = inode_name(ino, 0); | |
226 | if(name == NULL) | |
227 | goto out; | |
228 | ||
229 | if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){ | |
230 | name = follow_link(name); | |
231 | if(IS_ERR(name)){ | |
232 | err = PTR_ERR(name); | |
233 | goto out; | |
234 | } | |
235 | } | |
236 | ||
237 | err = read_name(ino, name); | |
238 | kfree(name); | |
239 | out: | |
240 | return(err); | |
241 | } | |
242 | ||
243 | int hostfs_statfs(struct super_block *sb, struct kstatfs *sf) | |
244 | { | |
245 | /* do_statfs uses struct statfs64 internally, but the linux kernel | |
246 | * struct statfs still has 32-bit versions for most of these fields, | |
247 | * so we convert them here | |
248 | */ | |
249 | int err; | |
250 | long long f_blocks; | |
251 | long long f_bfree; | |
252 | long long f_bavail; | |
253 | long long f_files; | |
254 | long long f_ffree; | |
255 | ||
256 | err = do_statfs(HOSTFS_I(sb->s_root->d_inode)->host_filename, | |
257 | &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, | |
258 | &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), | |
259 | &sf->f_namelen, sf->f_spare); | |
260 | if(err) return(err); | |
261 | sf->f_blocks = f_blocks; | |
262 | sf->f_bfree = f_bfree; | |
263 | sf->f_bavail = f_bavail; | |
264 | sf->f_files = f_files; | |
265 | sf->f_ffree = f_ffree; | |
266 | sf->f_type = HOSTFS_SUPER_MAGIC; | |
267 | return(0); | |
268 | } | |
269 | ||
270 | static struct inode *hostfs_alloc_inode(struct super_block *sb) | |
271 | { | |
272 | struct hostfs_inode_info *hi; | |
273 | ||
274 | hi = kmalloc(sizeof(*hi), GFP_KERNEL); | |
275 | if(hi == NULL) | |
276 | return(NULL); | |
277 | ||
278 | *hi = ((struct hostfs_inode_info) { .host_filename = NULL, | |
279 | .fd = -1, | |
280 | .mode = 0 }); | |
281 | inode_init_once(&hi->vfs_inode); | |
282 | return(&hi->vfs_inode); | |
283 | } | |
284 | ||
285 | static void hostfs_delete_inode(struct inode *inode) | |
286 | { | |
fef26658 | 287 | truncate_inode_pages(&inode->i_data, 0); |
1da177e4 LT |
288 | if(HOSTFS_I(inode)->fd != -1) { |
289 | close_file(&HOSTFS_I(inode)->fd); | |
290 | HOSTFS_I(inode)->fd = -1; | |
291 | } | |
292 | clear_inode(inode); | |
293 | } | |
294 | ||
295 | static void hostfs_destroy_inode(struct inode *inode) | |
296 | { | |
297 | if(HOSTFS_I(inode)->host_filename) | |
298 | kfree(HOSTFS_I(inode)->host_filename); | |
299 | ||
300 | /*XXX: This should not happen, probably. The check is here for | |
301 | * additional safety.*/ | |
302 | if(HOSTFS_I(inode)->fd != -1) { | |
303 | close_file(&HOSTFS_I(inode)->fd); | |
304 | printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); | |
305 | } | |
306 | ||
307 | kfree(HOSTFS_I(inode)); | |
308 | } | |
309 | ||
310 | static void hostfs_read_inode(struct inode *inode) | |
311 | { | |
312 | read_inode(inode); | |
313 | } | |
314 | ||
315 | static struct super_operations hostfs_sbops = { | |
316 | .alloc_inode = hostfs_alloc_inode, | |
317 | .drop_inode = generic_delete_inode, | |
318 | .delete_inode = hostfs_delete_inode, | |
319 | .destroy_inode = hostfs_destroy_inode, | |
320 | .read_inode = hostfs_read_inode, | |
321 | .statfs = hostfs_statfs, | |
322 | }; | |
323 | ||
324 | int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) | |
325 | { | |
326 | void *dir; | |
327 | char *name; | |
328 | unsigned long long next, ino; | |
329 | int error, len; | |
330 | ||
331 | name = dentry_name(file->f_dentry, 0); | |
332 | if(name == NULL) return(-ENOMEM); | |
333 | dir = open_dir(name, &error); | |
334 | kfree(name); | |
335 | if(dir == NULL) return(-error); | |
336 | next = file->f_pos; | |
337 | while((name = read_dir(dir, &next, &ino, &len)) != NULL){ | |
338 | error = (*filldir)(ent, name, len, file->f_pos, | |
339 | ino, DT_UNKNOWN); | |
340 | if(error) break; | |
341 | file->f_pos = next; | |
342 | } | |
343 | close_dir(dir); | |
344 | return(0); | |
345 | } | |
346 | ||
347 | int hostfs_file_open(struct inode *ino, struct file *file) | |
348 | { | |
349 | char *name; | |
350 | int mode = 0, r = 0, w = 0, fd; | |
351 | ||
352 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); | |
353 | if((mode & HOSTFS_I(ino)->mode) == mode) | |
354 | return(0); | |
355 | ||
356 | /* The file may already have been opened, but with the wrong access, | |
357 | * so this resets things and reopens the file with the new access. | |
358 | */ | |
359 | if(HOSTFS_I(ino)->fd != -1){ | |
360 | close_file(&HOSTFS_I(ino)->fd); | |
361 | HOSTFS_I(ino)->fd = -1; | |
362 | } | |
363 | ||
364 | HOSTFS_I(ino)->mode |= mode; | |
365 | if(HOSTFS_I(ino)->mode & FMODE_READ) | |
366 | r = 1; | |
367 | if(HOSTFS_I(ino)->mode & FMODE_WRITE) | |
368 | w = 1; | |
369 | if(w) | |
370 | r = 1; | |
371 | ||
372 | name = dentry_name(file->f_dentry, 0); | |
373 | if(name == NULL) | |
374 | return(-ENOMEM); | |
375 | ||
376 | fd = open_file(name, r, w, append); | |
377 | kfree(name); | |
378 | if(fd < 0) return(fd); | |
379 | FILE_HOSTFS_I(file)->fd = fd; | |
380 | ||
381 | return(0); | |
382 | } | |
383 | ||
384 | int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync) | |
385 | { | |
a2d76bd8 | 386 | return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync); |
1da177e4 LT |
387 | } |
388 | ||
389 | static struct file_operations hostfs_file_fops = { | |
390 | .llseek = generic_file_llseek, | |
391 | .read = generic_file_read, | |
392 | .sendfile = generic_file_sendfile, | |
393 | .aio_read = generic_file_aio_read, | |
394 | .aio_write = generic_file_aio_write, | |
395 | .readv = generic_file_readv, | |
396 | .writev = generic_file_writev, | |
397 | .write = generic_file_write, | |
398 | .mmap = generic_file_mmap, | |
399 | .open = hostfs_file_open, | |
400 | .release = NULL, | |
401 | .fsync = hostfs_fsync, | |
402 | }; | |
403 | ||
404 | static struct file_operations hostfs_dir_fops = { | |
405 | .llseek = generic_file_llseek, | |
406 | .readdir = hostfs_readdir, | |
407 | .read = generic_read_dir, | |
408 | }; | |
409 | ||
410 | int hostfs_writepage(struct page *page, struct writeback_control *wbc) | |
411 | { | |
412 | struct address_space *mapping = page->mapping; | |
413 | struct inode *inode = mapping->host; | |
414 | char *buffer; | |
415 | unsigned long long base; | |
416 | int count = PAGE_CACHE_SIZE; | |
417 | int end_index = inode->i_size >> PAGE_CACHE_SHIFT; | |
418 | int err; | |
419 | ||
420 | if (page->index >= end_index) | |
421 | count = inode->i_size & (PAGE_CACHE_SIZE-1); | |
422 | ||
423 | buffer = kmap(page); | |
424 | base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; | |
425 | ||
426 | err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); | |
427 | if(err != count){ | |
428 | ClearPageUptodate(page); | |
429 | goto out; | |
430 | } | |
431 | ||
432 | if (base > inode->i_size) | |
433 | inode->i_size = base; | |
434 | ||
435 | if (PageError(page)) | |
436 | ClearPageError(page); | |
437 | err = 0; | |
438 | ||
439 | out: | |
440 | kunmap(page); | |
441 | ||
442 | unlock_page(page); | |
443 | return err; | |
444 | } | |
445 | ||
446 | int hostfs_readpage(struct file *file, struct page *page) | |
447 | { | |
448 | char *buffer; | |
449 | long long start; | |
450 | int err = 0; | |
451 | ||
452 | start = (long long) page->index << PAGE_CACHE_SHIFT; | |
453 | buffer = kmap(page); | |
454 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, | |
455 | PAGE_CACHE_SIZE); | |
456 | if(err < 0) goto out; | |
457 | ||
458 | memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); | |
459 | ||
460 | flush_dcache_page(page); | |
461 | SetPageUptodate(page); | |
462 | if (PageError(page)) ClearPageError(page); | |
463 | err = 0; | |
464 | out: | |
465 | kunmap(page); | |
466 | unlock_page(page); | |
467 | return(err); | |
468 | } | |
469 | ||
470 | int hostfs_prepare_write(struct file *file, struct page *page, | |
471 | unsigned int from, unsigned int to) | |
472 | { | |
473 | char *buffer; | |
474 | long long start, tmp; | |
475 | int err; | |
476 | ||
477 | start = (long long) page->index << PAGE_CACHE_SHIFT; | |
478 | buffer = kmap(page); | |
479 | if(from != 0){ | |
480 | tmp = start; | |
481 | err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer, | |
482 | from); | |
483 | if(err < 0) goto out; | |
484 | } | |
485 | if(to != PAGE_CACHE_SIZE){ | |
486 | start += to; | |
487 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to, | |
488 | PAGE_CACHE_SIZE - to); | |
489 | if(err < 0) goto out; | |
490 | } | |
491 | err = 0; | |
492 | out: | |
493 | kunmap(page); | |
494 | return(err); | |
495 | } | |
496 | ||
497 | int hostfs_commit_write(struct file *file, struct page *page, unsigned from, | |
498 | unsigned to) | |
499 | { | |
500 | struct address_space *mapping = page->mapping; | |
501 | struct inode *inode = mapping->host; | |
502 | char *buffer; | |
503 | long long start; | |
504 | int err = 0; | |
505 | ||
506 | start = (long long) (page->index << PAGE_CACHE_SHIFT) + from; | |
507 | buffer = kmap(page); | |
508 | err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from, | |
509 | to - from); | |
510 | if(err > 0) err = 0; | |
511 | if(!err && (start > inode->i_size)) | |
512 | inode->i_size = start; | |
513 | ||
514 | kunmap(page); | |
515 | return(err); | |
516 | } | |
517 | ||
518 | static struct address_space_operations hostfs_aops = { | |
519 | .writepage = hostfs_writepage, | |
520 | .readpage = hostfs_readpage, | |
ffa0aea6 | 521 | .set_page_dirty = __set_page_dirty_nobuffers, |
1da177e4 LT |
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, 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 | void hostfs_truncate(struct inode *ino) | |
797 | { | |
798 | not_implemented(); | |
799 | } | |
800 | ||
801 | int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd) | |
802 | { | |
803 | char *name; | |
804 | int r = 0, w = 0, x = 0, err; | |
805 | ||
806 | if (desired & MAY_READ) r = 1; | |
807 | if (desired & MAY_WRITE) w = 1; | |
808 | if (desired & MAY_EXEC) x = 1; | |
809 | name = inode_name(ino, 0); | |
810 | if (name == NULL) return(-ENOMEM); | |
811 | ||
812 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || | |
813 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) | |
814 | err = 0; | |
815 | else | |
816 | err = access_file(name, r, w, x); | |
817 | kfree(name); | |
818 | if(!err) | |
819 | err = generic_permission(ino, desired, NULL); | |
820 | return err; | |
821 | } | |
822 | ||
823 | int hostfs_setattr(struct dentry *dentry, struct iattr *attr) | |
824 | { | |
825 | struct hostfs_iattr attrs; | |
826 | char *name; | |
827 | int err; | |
828 | ||
829 | err = inode_change_ok(dentry->d_inode, attr); | |
830 | if (err) | |
831 | return err; | |
832 | ||
833 | if(append) | |
834 | attr->ia_valid &= ~ATTR_SIZE; | |
835 | ||
836 | attrs.ia_valid = 0; | |
837 | if(attr->ia_valid & ATTR_MODE){ | |
838 | attrs.ia_valid |= HOSTFS_ATTR_MODE; | |
839 | attrs.ia_mode = attr->ia_mode; | |
840 | } | |
841 | if(attr->ia_valid & ATTR_UID){ | |
1da177e4 LT |
842 | attrs.ia_valid |= HOSTFS_ATTR_UID; |
843 | attrs.ia_uid = attr->ia_uid; | |
844 | } | |
845 | if(attr->ia_valid & ATTR_GID){ | |
1da177e4 LT |
846 | attrs.ia_valid |= HOSTFS_ATTR_GID; |
847 | attrs.ia_gid = attr->ia_gid; | |
848 | } | |
849 | if(attr->ia_valid & ATTR_SIZE){ | |
850 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; | |
851 | attrs.ia_size = attr->ia_size; | |
852 | } | |
853 | if(attr->ia_valid & ATTR_ATIME){ | |
854 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; | |
855 | attrs.ia_atime = attr->ia_atime; | |
856 | } | |
857 | if(attr->ia_valid & ATTR_MTIME){ | |
858 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; | |
859 | attrs.ia_mtime = attr->ia_mtime; | |
860 | } | |
861 | if(attr->ia_valid & ATTR_CTIME){ | |
862 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; | |
863 | attrs.ia_ctime = attr->ia_ctime; | |
864 | } | |
865 | if(attr->ia_valid & ATTR_ATIME_SET){ | |
866 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; | |
867 | } | |
868 | if(attr->ia_valid & ATTR_MTIME_SET){ | |
869 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; | |
870 | } | |
871 | name = dentry_name(dentry, 0); | |
872 | if(name == NULL) return(-ENOMEM); | |
873 | err = set_attr(name, &attrs); | |
874 | kfree(name); | |
875 | if(err) | |
876 | return(err); | |
877 | ||
878 | return(inode_setattr(dentry->d_inode, attr)); | |
879 | } | |
880 | ||
881 | int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
882 | struct kstat *stat) | |
883 | { | |
884 | generic_fillattr(dentry->d_inode, stat); | |
885 | return(0); | |
886 | } | |
887 | ||
888 | static struct inode_operations hostfs_iops = { | |
889 | .create = hostfs_create, | |
890 | .link = hostfs_link, | |
891 | .unlink = hostfs_unlink, | |
892 | .symlink = hostfs_symlink, | |
893 | .mkdir = hostfs_mkdir, | |
894 | .rmdir = hostfs_rmdir, | |
895 | .mknod = hostfs_mknod, | |
896 | .rename = hostfs_rename, | |
897 | .truncate = hostfs_truncate, | |
898 | .permission = hostfs_permission, | |
899 | .setattr = hostfs_setattr, | |
900 | .getattr = hostfs_getattr, | |
901 | }; | |
902 | ||
903 | static struct inode_operations hostfs_dir_iops = { | |
904 | .create = hostfs_create, | |
905 | .lookup = hostfs_lookup, | |
906 | .link = hostfs_link, | |
907 | .unlink = hostfs_unlink, | |
908 | .symlink = hostfs_symlink, | |
909 | .mkdir = hostfs_mkdir, | |
910 | .rmdir = hostfs_rmdir, | |
911 | .mknod = hostfs_mknod, | |
912 | .rename = hostfs_rename, | |
913 | .truncate = hostfs_truncate, | |
914 | .permission = hostfs_permission, | |
915 | .setattr = hostfs_setattr, | |
916 | .getattr = hostfs_getattr, | |
917 | }; | |
918 | ||
919 | int hostfs_link_readpage(struct file *file, struct page *page) | |
920 | { | |
921 | char *buffer, *name; | |
922 | long long start; | |
923 | int err; | |
924 | ||
925 | start = page->index << PAGE_CACHE_SHIFT; | |
926 | buffer = kmap(page); | |
927 | name = inode_name(page->mapping->host, 0); | |
928 | if(name == NULL) return(-ENOMEM); | |
929 | err = do_readlink(name, buffer, PAGE_CACHE_SIZE); | |
930 | kfree(name); | |
931 | if(err == PAGE_CACHE_SIZE) | |
932 | err = -E2BIG; | |
933 | else if(err > 0){ | |
934 | flush_dcache_page(page); | |
935 | SetPageUptodate(page); | |
936 | if (PageError(page)) ClearPageError(page); | |
937 | err = 0; | |
938 | } | |
939 | kunmap(page); | |
940 | unlock_page(page); | |
941 | return(err); | |
942 | } | |
943 | ||
944 | static struct address_space_operations hostfs_link_aops = { | |
945 | .readpage = hostfs_link_readpage, | |
946 | }; | |
947 | ||
948 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) | |
949 | { | |
950 | struct inode *root_inode; | |
951 | char *name, *data = d; | |
952 | int err; | |
953 | ||
954 | sb->s_blocksize = 1024; | |
955 | sb->s_blocksize_bits = 10; | |
956 | sb->s_magic = HOSTFS_SUPER_MAGIC; | |
957 | sb->s_op = &hostfs_sbops; | |
958 | ||
959 | if((data == NULL) || (*data == '\0')) | |
960 | data = root_ino; | |
961 | ||
962 | err = -ENOMEM; | |
963 | name = kmalloc(strlen(data) + 1, GFP_KERNEL); | |
964 | if(name == NULL) | |
965 | goto out; | |
966 | ||
967 | strcpy(name, data); | |
968 | ||
969 | root_inode = iget(sb, 0); | |
970 | if(root_inode == NULL) | |
971 | goto out_free; | |
972 | ||
973 | err = init_inode(root_inode, NULL); | |
974 | if(err) | |
975 | goto out_put; | |
976 | ||
977 | HOSTFS_I(root_inode)->host_filename = name; | |
978 | ||
979 | err = -ENOMEM; | |
980 | sb->s_root = d_alloc_root(root_inode); | |
981 | if(sb->s_root == NULL) | |
982 | goto out_put; | |
983 | ||
984 | err = read_inode(root_inode); | |
51a14110 JD |
985 | if(err){ |
986 | /* No iput in this case because the dput does that for us */ | |
987 | dput(sb->s_root); | |
988 | sb->s_root = NULL; | |
989 | goto out_free; | |
990 | } | |
1da177e4 LT |
991 | |
992 | return(0); | |
993 | ||
994 | out_put: | |
51a14110 | 995 | iput(root_inode); |
1da177e4 LT |
996 | out_free: |
997 | kfree(name); | |
998 | out: | |
999 | return(err); | |
1000 | } | |
1001 | ||
1002 | static struct super_block *hostfs_read_sb(struct file_system_type *type, | |
1003 | int flags, const char *dev_name, | |
1004 | void *data) | |
1005 | { | |
1006 | return(get_sb_nodev(type, flags, data, hostfs_fill_sb_common)); | |
1007 | } | |
1008 | ||
1009 | static struct file_system_type hostfs_type = { | |
1010 | .owner = THIS_MODULE, | |
1011 | .name = "hostfs", | |
1012 | .get_sb = hostfs_read_sb, | |
1013 | .kill_sb = kill_anon_super, | |
1014 | .fs_flags = 0, | |
1015 | }; | |
1016 | ||
1017 | static int __init init_hostfs(void) | |
1018 | { | |
1019 | return(register_filesystem(&hostfs_type)); | |
1020 | } | |
1021 | ||
1022 | static void __exit exit_hostfs(void) | |
1023 | { | |
1024 | unregister_filesystem(&hostfs_type); | |
1025 | } | |
1026 | ||
1027 | module_init(init_hostfs) | |
1028 | module_exit(exit_hostfs) | |
1029 | MODULE_LICENSE("GPL"); | |
1030 | ||
1031 | /* | |
1032 | * Overrides for Emacs so that we follow Linus's tabbing style. | |
1033 | * Emacs will notice this stuff at the end of the file and automatically | |
1034 | * adjust the settings for this buffer only. This must remain at the end | |
1035 | * of the file. | |
1036 | * --------------------------------------------------------------------------- | |
1037 | * Local variables: | |
1038 | * c-file-style: "linux" | |
1039 | * End: | |
1040 | */ |