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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> | |
18 | #include <linux/root_dev.h> | |
19 | #include <linux/statfs.h> | |
20 | #include <linux/kdev_t.h> | |
21 | #include <asm/uaccess.h> | |
22 | #include "hostfs.h" | |
23 | #include "kern_util.h" | |
24 | #include "kern.h" | |
25 | #include "user_util.h" | |
26 | #include "2_5compat.h" | |
27 | #include "init.h" | |
28 | ||
29 | struct hostfs_inode_info { | |
30 | char *host_filename; | |
31 | int fd; | |
32 | int mode; | |
33 | struct inode vfs_inode; | |
34 | }; | |
35 | ||
36 | static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) | |
37 | { | |
38 | return(list_entry(inode, struct hostfs_inode_info, vfs_inode)); | |
39 | } | |
40 | ||
41 | #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_dentry->d_inode) | |
42 | ||
43 | int hostfs_d_delete(struct dentry *dentry) | |
44 | { | |
45 | return(1); | |
46 | } | |
47 | ||
48 | struct dentry_operations hostfs_dentry_ops = { | |
49 | .d_delete = hostfs_d_delete, | |
50 | }; | |
51 | ||
52 | /* Changed in hostfs_args before the kernel starts running */ | |
53 | static char *root_ino = "/"; | |
54 | static int append = 0; | |
55 | ||
56 | #define HOSTFS_SUPER_MAGIC 0x00c0ffee | |
57 | ||
58 | static struct inode_operations hostfs_iops; | |
59 | static struct inode_operations hostfs_dir_iops; | |
60 | static struct address_space_operations hostfs_link_aops; | |
61 | ||
62 | #ifndef MODULE | |
63 | static int __init hostfs_args(char *options, int *add) | |
64 | { | |
65 | char *ptr; | |
66 | ||
67 | ptr = strchr(options, ','); | |
68 | if(ptr != NULL) | |
69 | *ptr++ = '\0'; | |
70 | if(*options != '\0') | |
71 | root_ino = options; | |
72 | ||
73 | options = ptr; | |
74 | while(options){ | |
75 | ptr = strchr(options, ','); | |
76 | if(ptr != NULL) | |
77 | *ptr++ = '\0'; | |
78 | if(*options != '\0'){ | |
79 | if(!strcmp(options, "append")) | |
80 | append = 1; | |
81 | else printf("hostfs_args - unsupported option - %s\n", | |
82 | options); | |
83 | } | |
84 | options = ptr; | |
85 | } | |
86 | return(0); | |
87 | } | |
88 | ||
89 | __uml_setup("hostfs=", hostfs_args, | |
90 | "hostfs=<root dir>,<flags>,...\n" | |
91 | " This is used to set hostfs parameters. The root directory argument\n" | |
92 | " is used to confine all hostfs mounts to within the specified directory\n" | |
93 | " tree on the host. If this isn't specified, then a user inside UML can\n" | |
94 | " mount anything on the host that's accessible to the user that's running\n" | |
95 | " it.\n" | |
96 | " The only flag currently supported is 'append', which specifies that all\n" | |
97 | " files opened by hostfs will be opened in append mode.\n\n" | |
98 | ); | |
99 | #endif | |
100 | ||
101 | static char *dentry_name(struct dentry *dentry, int extra) | |
102 | { | |
103 | struct dentry *parent; | |
104 | char *root, *name; | |
105 | int len; | |
106 | ||
107 | len = 0; | |
108 | parent = dentry; | |
109 | while(parent->d_parent != parent){ | |
110 | len += parent->d_name.len + 1; | |
111 | parent = parent->d_parent; | |
112 | } | |
113 | ||
114 | root = HOSTFS_I(parent->d_inode)->host_filename; | |
115 | len += strlen(root); | |
116 | name = kmalloc(len + extra + 1, GFP_KERNEL); | |
117 | if(name == NULL) return(NULL); | |
118 | ||
119 | name[len] = '\0'; | |
120 | parent = dentry; | |
121 | while(parent->d_parent != parent){ | |
122 | len -= parent->d_name.len + 1; | |
123 | name[len] = '/'; | |
124 | strncpy(&name[len + 1], parent->d_name.name, | |
125 | parent->d_name.len); | |
126 | parent = parent->d_parent; | |
127 | } | |
128 | strncpy(name, root, strlen(root)); | |
129 | return(name); | |
130 | } | |
131 | ||
132 | static char *inode_name(struct inode *ino, int extra) | |
133 | { | |
134 | struct dentry *dentry; | |
135 | ||
136 | dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); | |
137 | return(dentry_name(dentry, extra)); | |
138 | } | |
139 | ||
140 | static int read_name(struct inode *ino, char *name) | |
141 | { | |
142 | /* The non-int inode fields are copied into ints by stat_file and | |
143 | * then copied into the inode because passing the actual pointers | |
144 | * in and having them treated as int * breaks on big-endian machines | |
145 | */ | |
146 | int err; | |
147 | int i_mode, i_nlink, i_blksize; | |
148 | unsigned long long i_size; | |
149 | unsigned long long i_ino; | |
150 | unsigned long long i_blocks; | |
151 | ||
152 | err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, | |
153 | &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, | |
154 | &ino->i_ctime, &i_blksize, &i_blocks); | |
155 | if(err) | |
156 | return(err); | |
157 | ||
158 | ino->i_ino = i_ino; | |
159 | ino->i_mode = i_mode; | |
160 | ino->i_nlink = i_nlink; | |
161 | ino->i_size = i_size; | |
162 | ino->i_blksize = i_blksize; | |
163 | ino->i_blocks = i_blocks; | |
164 | if((ino->i_sb->s_dev == ROOT_DEV) && (ino->i_uid == getuid())) | |
165 | ino->i_uid = 0; | |
166 | return(0); | |
167 | } | |
168 | ||
169 | static char *follow_link(char *link) | |
170 | { | |
171 | int len, n; | |
172 | char *name, *resolved, *end; | |
173 | ||
174 | len = 64; | |
175 | while(1){ | |
176 | n = -ENOMEM; | |
177 | name = kmalloc(len, GFP_KERNEL); | |
178 | if(name == NULL) | |
179 | goto out; | |
180 | ||
181 | n = do_readlink(link, name, len); | |
182 | if(n < len) | |
183 | break; | |
184 | len *= 2; | |
185 | kfree(name); | |
186 | } | |
187 | if(n < 0) | |
188 | goto out_free; | |
189 | ||
190 | if(*name == '/') | |
191 | return(name); | |
192 | ||
193 | end = strrchr(link, '/'); | |
194 | if(end == NULL) | |
195 | return(name); | |
196 | ||
197 | *(end + 1) = '\0'; | |
198 | len = strlen(link) + strlen(name) + 1; | |
199 | ||
200 | resolved = kmalloc(len, GFP_KERNEL); | |
201 | if(resolved == NULL){ | |
202 | n = -ENOMEM; | |
203 | goto out_free; | |
204 | } | |
205 | ||
206 | sprintf(resolved, "%s%s", link, name); | |
207 | kfree(name); | |
208 | kfree(link); | |
209 | return(resolved); | |
210 | ||
211 | out_free: | |
212 | kfree(name); | |
213 | out: | |
214 | return(ERR_PTR(n)); | |
215 | } | |
216 | ||
217 | static int read_inode(struct inode *ino) | |
218 | { | |
219 | char *name; | |
220 | int err = 0; | |
221 | ||
222 | /* Unfortunately, we are called from iget() when we don't have a dentry | |
223 | * allocated yet. | |
224 | */ | |
225 | if(list_empty(&ino->i_dentry)) | |
226 | goto out; | |
227 | ||
228 | err = -ENOMEM; | |
229 | name = inode_name(ino, 0); | |
230 | if(name == NULL) | |
231 | goto out; | |
232 | ||
233 | if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){ | |
234 | name = follow_link(name); | |
235 | if(IS_ERR(name)){ | |
236 | err = PTR_ERR(name); | |
237 | goto out; | |
238 | } | |
239 | } | |
240 | ||
241 | err = read_name(ino, name); | |
242 | kfree(name); | |
243 | out: | |
244 | return(err); | |
245 | } | |
246 | ||
247 | int hostfs_statfs(struct super_block *sb, struct kstatfs *sf) | |
248 | { | |
249 | /* do_statfs uses struct statfs64 internally, but the linux kernel | |
250 | * struct statfs still has 32-bit versions for most of these fields, | |
251 | * so we convert them here | |
252 | */ | |
253 | int err; | |
254 | long long f_blocks; | |
255 | long long f_bfree; | |
256 | long long f_bavail; | |
257 | long long f_files; | |
258 | long long f_ffree; | |
259 | ||
260 | err = do_statfs(HOSTFS_I(sb->s_root->d_inode)->host_filename, | |
261 | &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, | |
262 | &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), | |
263 | &sf->f_namelen, sf->f_spare); | |
264 | if(err) return(err); | |
265 | sf->f_blocks = f_blocks; | |
266 | sf->f_bfree = f_bfree; | |
267 | sf->f_bavail = f_bavail; | |
268 | sf->f_files = f_files; | |
269 | sf->f_ffree = f_ffree; | |
270 | sf->f_type = HOSTFS_SUPER_MAGIC; | |
271 | return(0); | |
272 | } | |
273 | ||
274 | static struct inode *hostfs_alloc_inode(struct super_block *sb) | |
275 | { | |
276 | struct hostfs_inode_info *hi; | |
277 | ||
278 | hi = kmalloc(sizeof(*hi), GFP_KERNEL); | |
279 | if(hi == NULL) | |
280 | return(NULL); | |
281 | ||
282 | *hi = ((struct hostfs_inode_info) { .host_filename = NULL, | |
283 | .fd = -1, | |
284 | .mode = 0 }); | |
285 | inode_init_once(&hi->vfs_inode); | |
286 | return(&hi->vfs_inode); | |
287 | } | |
288 | ||
289 | static void hostfs_delete_inode(struct inode *inode) | |
290 | { | |
291 | if(HOSTFS_I(inode)->fd != -1) { | |
292 | close_file(&HOSTFS_I(inode)->fd); | |
293 | HOSTFS_I(inode)->fd = -1; | |
294 | } | |
295 | clear_inode(inode); | |
296 | } | |
297 | ||
298 | static void hostfs_destroy_inode(struct inode *inode) | |
299 | { | |
300 | if(HOSTFS_I(inode)->host_filename) | |
301 | kfree(HOSTFS_I(inode)->host_filename); | |
302 | ||
303 | /*XXX: This should not happen, probably. The check is here for | |
304 | * additional safety.*/ | |
305 | if(HOSTFS_I(inode)->fd != -1) { | |
306 | close_file(&HOSTFS_I(inode)->fd); | |
307 | printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); | |
308 | } | |
309 | ||
310 | kfree(HOSTFS_I(inode)); | |
311 | } | |
312 | ||
313 | static void hostfs_read_inode(struct inode *inode) | |
314 | { | |
315 | read_inode(inode); | |
316 | } | |
317 | ||
318 | static struct super_operations hostfs_sbops = { | |
319 | .alloc_inode = hostfs_alloc_inode, | |
320 | .drop_inode = generic_delete_inode, | |
321 | .delete_inode = hostfs_delete_inode, | |
322 | .destroy_inode = hostfs_destroy_inode, | |
323 | .read_inode = hostfs_read_inode, | |
324 | .statfs = hostfs_statfs, | |
325 | }; | |
326 | ||
327 | int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) | |
328 | { | |
329 | void *dir; | |
330 | char *name; | |
331 | unsigned long long next, ino; | |
332 | int error, len; | |
333 | ||
334 | name = dentry_name(file->f_dentry, 0); | |
335 | if(name == NULL) return(-ENOMEM); | |
336 | dir = open_dir(name, &error); | |
337 | kfree(name); | |
338 | if(dir == NULL) return(-error); | |
339 | next = file->f_pos; | |
340 | while((name = read_dir(dir, &next, &ino, &len)) != NULL){ | |
341 | error = (*filldir)(ent, name, len, file->f_pos, | |
342 | ino, DT_UNKNOWN); | |
343 | if(error) break; | |
344 | file->f_pos = next; | |
345 | } | |
346 | close_dir(dir); | |
347 | return(0); | |
348 | } | |
349 | ||
350 | int hostfs_file_open(struct inode *ino, struct file *file) | |
351 | { | |
352 | char *name; | |
353 | int mode = 0, r = 0, w = 0, fd; | |
354 | ||
355 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); | |
356 | if((mode & HOSTFS_I(ino)->mode) == mode) | |
357 | return(0); | |
358 | ||
359 | /* The file may already have been opened, but with the wrong access, | |
360 | * so this resets things and reopens the file with the new access. | |
361 | */ | |
362 | if(HOSTFS_I(ino)->fd != -1){ | |
363 | close_file(&HOSTFS_I(ino)->fd); | |
364 | HOSTFS_I(ino)->fd = -1; | |
365 | } | |
366 | ||
367 | HOSTFS_I(ino)->mode |= mode; | |
368 | if(HOSTFS_I(ino)->mode & FMODE_READ) | |
369 | r = 1; | |
370 | if(HOSTFS_I(ino)->mode & FMODE_WRITE) | |
371 | w = 1; | |
372 | if(w) | |
373 | r = 1; | |
374 | ||
375 | name = dentry_name(file->f_dentry, 0); | |
376 | if(name == NULL) | |
377 | return(-ENOMEM); | |
378 | ||
379 | fd = open_file(name, r, w, append); | |
380 | kfree(name); | |
381 | if(fd < 0) return(fd); | |
382 | FILE_HOSTFS_I(file)->fd = fd; | |
383 | ||
384 | return(0); | |
385 | } | |
386 | ||
387 | int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync) | |
388 | { | |
389 | return(0); | |
390 | } | |
391 | ||
392 | static struct file_operations hostfs_file_fops = { | |
393 | .llseek = generic_file_llseek, | |
394 | .read = generic_file_read, | |
395 | .sendfile = generic_file_sendfile, | |
396 | .aio_read = generic_file_aio_read, | |
397 | .aio_write = generic_file_aio_write, | |
398 | .readv = generic_file_readv, | |
399 | .writev = generic_file_writev, | |
400 | .write = generic_file_write, | |
401 | .mmap = generic_file_mmap, | |
402 | .open = hostfs_file_open, | |
403 | .release = NULL, | |
404 | .fsync = hostfs_fsync, | |
405 | }; | |
406 | ||
407 | static struct file_operations hostfs_dir_fops = { | |
408 | .llseek = generic_file_llseek, | |
409 | .readdir = hostfs_readdir, | |
410 | .read = generic_read_dir, | |
411 | }; | |
412 | ||
413 | int hostfs_writepage(struct page *page, struct writeback_control *wbc) | |
414 | { | |
415 | struct address_space *mapping = page->mapping; | |
416 | struct inode *inode = mapping->host; | |
417 | char *buffer; | |
418 | unsigned long long base; | |
419 | int count = PAGE_CACHE_SIZE; | |
420 | int end_index = inode->i_size >> PAGE_CACHE_SHIFT; | |
421 | int err; | |
422 | ||
423 | if (page->index >= end_index) | |
424 | count = inode->i_size & (PAGE_CACHE_SIZE-1); | |
425 | ||
426 | buffer = kmap(page); | |
427 | base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; | |
428 | ||
429 | err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); | |
430 | if(err != count){ | |
431 | ClearPageUptodate(page); | |
432 | goto out; | |
433 | } | |
434 | ||
435 | if (base > inode->i_size) | |
436 | inode->i_size = base; | |
437 | ||
438 | if (PageError(page)) | |
439 | ClearPageError(page); | |
440 | err = 0; | |
441 | ||
442 | out: | |
443 | kunmap(page); | |
444 | ||
445 | unlock_page(page); | |
446 | return err; | |
447 | } | |
448 | ||
449 | int hostfs_readpage(struct file *file, struct page *page) | |
450 | { | |
451 | char *buffer; | |
452 | long long start; | |
453 | int err = 0; | |
454 | ||
455 | start = (long long) page->index << PAGE_CACHE_SHIFT; | |
456 | buffer = kmap(page); | |
457 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, | |
458 | PAGE_CACHE_SIZE); | |
459 | if(err < 0) goto out; | |
460 | ||
461 | memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); | |
462 | ||
463 | flush_dcache_page(page); | |
464 | SetPageUptodate(page); | |
465 | if (PageError(page)) ClearPageError(page); | |
466 | err = 0; | |
467 | out: | |
468 | kunmap(page); | |
469 | unlock_page(page); | |
470 | return(err); | |
471 | } | |
472 | ||
473 | int hostfs_prepare_write(struct file *file, struct page *page, | |
474 | unsigned int from, unsigned int to) | |
475 | { | |
476 | char *buffer; | |
477 | long long start, tmp; | |
478 | int err; | |
479 | ||
480 | start = (long long) page->index << PAGE_CACHE_SHIFT; | |
481 | buffer = kmap(page); | |
482 | if(from != 0){ | |
483 | tmp = start; | |
484 | err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer, | |
485 | from); | |
486 | if(err < 0) goto out; | |
487 | } | |
488 | if(to != PAGE_CACHE_SIZE){ | |
489 | start += to; | |
490 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to, | |
491 | PAGE_CACHE_SIZE - to); | |
492 | if(err < 0) goto out; | |
493 | } | |
494 | err = 0; | |
495 | out: | |
496 | kunmap(page); | |
497 | return(err); | |
498 | } | |
499 | ||
500 | int hostfs_commit_write(struct file *file, struct page *page, unsigned from, | |
501 | unsigned to) | |
502 | { | |
503 | struct address_space *mapping = page->mapping; | |
504 | struct inode *inode = mapping->host; | |
505 | char *buffer; | |
506 | long long start; | |
507 | int err = 0; | |
508 | ||
509 | start = (long long) (page->index << PAGE_CACHE_SHIFT) + from; | |
510 | buffer = kmap(page); | |
511 | err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from, | |
512 | to - from); | |
513 | if(err > 0) err = 0; | |
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 | void hostfs_truncate(struct inode *ino) | |
800 | { | |
801 | not_implemented(); | |
802 | } | |
803 | ||
804 | int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd) | |
805 | { | |
806 | char *name; | |
807 | int r = 0, w = 0, x = 0, err; | |
808 | ||
809 | if (desired & MAY_READ) r = 1; | |
810 | if (desired & MAY_WRITE) w = 1; | |
811 | if (desired & MAY_EXEC) x = 1; | |
812 | name = inode_name(ino, 0); | |
813 | if (name == NULL) return(-ENOMEM); | |
814 | ||
815 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || | |
816 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) | |
817 | err = 0; | |
818 | else | |
819 | err = access_file(name, r, w, x); | |
820 | kfree(name); | |
821 | if(!err) | |
822 | err = generic_permission(ino, desired, NULL); | |
823 | return err; | |
824 | } | |
825 | ||
826 | int hostfs_setattr(struct dentry *dentry, struct iattr *attr) | |
827 | { | |
828 | struct hostfs_iattr attrs; | |
829 | char *name; | |
830 | int err; | |
831 | ||
832 | err = inode_change_ok(dentry->d_inode, attr); | |
833 | if (err) | |
834 | return err; | |
835 | ||
836 | if(append) | |
837 | attr->ia_valid &= ~ATTR_SIZE; | |
838 | ||
839 | attrs.ia_valid = 0; | |
840 | if(attr->ia_valid & ATTR_MODE){ | |
841 | attrs.ia_valid |= HOSTFS_ATTR_MODE; | |
842 | attrs.ia_mode = attr->ia_mode; | |
843 | } | |
844 | if(attr->ia_valid & ATTR_UID){ | |
845 | if((dentry->d_inode->i_sb->s_dev == ROOT_DEV) && | |
846 | (attr->ia_uid == 0)) | |
847 | attr->ia_uid = getuid(); | |
848 | attrs.ia_valid |= HOSTFS_ATTR_UID; | |
849 | attrs.ia_uid = attr->ia_uid; | |
850 | } | |
851 | if(attr->ia_valid & ATTR_GID){ | |
852 | if((dentry->d_inode->i_sb->s_dev == ROOT_DEV) && | |
853 | (attr->ia_gid == 0)) | |
854 | attr->ia_gid = getgid(); | |
855 | attrs.ia_valid |= HOSTFS_ATTR_GID; | |
856 | attrs.ia_gid = attr->ia_gid; | |
857 | } | |
858 | if(attr->ia_valid & ATTR_SIZE){ | |
859 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; | |
860 | attrs.ia_size = attr->ia_size; | |
861 | } | |
862 | if(attr->ia_valid & ATTR_ATIME){ | |
863 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; | |
864 | attrs.ia_atime = attr->ia_atime; | |
865 | } | |
866 | if(attr->ia_valid & ATTR_MTIME){ | |
867 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; | |
868 | attrs.ia_mtime = attr->ia_mtime; | |
869 | } | |
870 | if(attr->ia_valid & ATTR_CTIME){ | |
871 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; | |
872 | attrs.ia_ctime = attr->ia_ctime; | |
873 | } | |
874 | if(attr->ia_valid & ATTR_ATIME_SET){ | |
875 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; | |
876 | } | |
877 | if(attr->ia_valid & ATTR_MTIME_SET){ | |
878 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; | |
879 | } | |
880 | name = dentry_name(dentry, 0); | |
881 | if(name == NULL) return(-ENOMEM); | |
882 | err = set_attr(name, &attrs); | |
883 | kfree(name); | |
884 | if(err) | |
885 | return(err); | |
886 | ||
887 | return(inode_setattr(dentry->d_inode, attr)); | |
888 | } | |
889 | ||
890 | int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
891 | struct kstat *stat) | |
892 | { | |
893 | generic_fillattr(dentry->d_inode, stat); | |
894 | return(0); | |
895 | } | |
896 | ||
897 | static struct inode_operations hostfs_iops = { | |
898 | .create = hostfs_create, | |
899 | .link = hostfs_link, | |
900 | .unlink = hostfs_unlink, | |
901 | .symlink = hostfs_symlink, | |
902 | .mkdir = hostfs_mkdir, | |
903 | .rmdir = hostfs_rmdir, | |
904 | .mknod = hostfs_mknod, | |
905 | .rename = hostfs_rename, | |
906 | .truncate = hostfs_truncate, | |
907 | .permission = hostfs_permission, | |
908 | .setattr = hostfs_setattr, | |
909 | .getattr = hostfs_getattr, | |
910 | }; | |
911 | ||
912 | static struct inode_operations hostfs_dir_iops = { | |
913 | .create = hostfs_create, | |
914 | .lookup = hostfs_lookup, | |
915 | .link = hostfs_link, | |
916 | .unlink = hostfs_unlink, | |
917 | .symlink = hostfs_symlink, | |
918 | .mkdir = hostfs_mkdir, | |
919 | .rmdir = hostfs_rmdir, | |
920 | .mknod = hostfs_mknod, | |
921 | .rename = hostfs_rename, | |
922 | .truncate = hostfs_truncate, | |
923 | .permission = hostfs_permission, | |
924 | .setattr = hostfs_setattr, | |
925 | .getattr = hostfs_getattr, | |
926 | }; | |
927 | ||
928 | int hostfs_link_readpage(struct file *file, struct page *page) | |
929 | { | |
930 | char *buffer, *name; | |
931 | long long start; | |
932 | int err; | |
933 | ||
934 | start = page->index << PAGE_CACHE_SHIFT; | |
935 | buffer = kmap(page); | |
936 | name = inode_name(page->mapping->host, 0); | |
937 | if(name == NULL) return(-ENOMEM); | |
938 | err = do_readlink(name, buffer, PAGE_CACHE_SIZE); | |
939 | kfree(name); | |
940 | if(err == PAGE_CACHE_SIZE) | |
941 | err = -E2BIG; | |
942 | else if(err > 0){ | |
943 | flush_dcache_page(page); | |
944 | SetPageUptodate(page); | |
945 | if (PageError(page)) ClearPageError(page); | |
946 | err = 0; | |
947 | } | |
948 | kunmap(page); | |
949 | unlock_page(page); | |
950 | return(err); | |
951 | } | |
952 | ||
953 | static struct address_space_operations hostfs_link_aops = { | |
954 | .readpage = hostfs_link_readpage, | |
955 | }; | |
956 | ||
957 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) | |
958 | { | |
959 | struct inode *root_inode; | |
960 | char *name, *data = d; | |
961 | int err; | |
962 | ||
963 | sb->s_blocksize = 1024; | |
964 | sb->s_blocksize_bits = 10; | |
965 | sb->s_magic = HOSTFS_SUPER_MAGIC; | |
966 | sb->s_op = &hostfs_sbops; | |
967 | ||
968 | if((data == NULL) || (*data == '\0')) | |
969 | data = root_ino; | |
970 | ||
971 | err = -ENOMEM; | |
972 | name = kmalloc(strlen(data) + 1, GFP_KERNEL); | |
973 | if(name == NULL) | |
974 | goto out; | |
975 | ||
976 | strcpy(name, data); | |
977 | ||
978 | root_inode = iget(sb, 0); | |
979 | if(root_inode == NULL) | |
980 | goto out_free; | |
981 | ||
982 | err = init_inode(root_inode, NULL); | |
983 | if(err) | |
984 | goto out_put; | |
985 | ||
986 | HOSTFS_I(root_inode)->host_filename = name; | |
987 | ||
988 | err = -ENOMEM; | |
989 | sb->s_root = d_alloc_root(root_inode); | |
990 | if(sb->s_root == NULL) | |
991 | goto out_put; | |
992 | ||
993 | err = read_inode(root_inode); | |
994 | if(err) | |
995 | goto out_put; | |
996 | ||
997 | return(0); | |
998 | ||
999 | out_put: | |
1000 | iput(root_inode); | |
1001 | out_free: | |
1002 | kfree(name); | |
1003 | out: | |
1004 | return(err); | |
1005 | } | |
1006 | ||
1007 | static struct super_block *hostfs_read_sb(struct file_system_type *type, | |
1008 | int flags, const char *dev_name, | |
1009 | void *data) | |
1010 | { | |
1011 | return(get_sb_nodev(type, flags, data, hostfs_fill_sb_common)); | |
1012 | } | |
1013 | ||
1014 | static struct file_system_type hostfs_type = { | |
1015 | .owner = THIS_MODULE, | |
1016 | .name = "hostfs", | |
1017 | .get_sb = hostfs_read_sb, | |
1018 | .kill_sb = kill_anon_super, | |
1019 | .fs_flags = 0, | |
1020 | }; | |
1021 | ||
1022 | static int __init init_hostfs(void) | |
1023 | { | |
1024 | return(register_filesystem(&hostfs_type)); | |
1025 | } | |
1026 | ||
1027 | static void __exit exit_hostfs(void) | |
1028 | { | |
1029 | unregister_filesystem(&hostfs_type); | |
1030 | } | |
1031 | ||
1032 | module_init(init_hostfs) | |
1033 | module_exit(exit_hostfs) | |
1034 | MODULE_LICENSE("GPL"); | |
1035 | ||
1036 | /* | |
1037 | * Overrides for Emacs so that we follow Linus's tabbing style. | |
1038 | * Emacs will notice this stuff at the end of the file and automatically | |
1039 | * adjust the settings for this buffer only. This must remain at the end | |
1040 | * of the file. | |
1041 | * --------------------------------------------------------------------------- | |
1042 | * Local variables: | |
1043 | * c-file-style: "linux" | |
1044 | * End: | |
1045 | */ |