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1 | /* | |
2 | * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.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/fs.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/mm.h> | |
12 | #include <linux/pagemap.h> | |
13 | #include <linux/statfs.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/seq_file.h> | |
16 | #include <linux/mount.h> | |
17 | #include <linux/namei.h> | |
18 | #include "hostfs.h" | |
19 | #include "init.h" | |
20 | #include "kern.h" | |
21 | ||
22 | struct hostfs_inode_info { | |
23 | int fd; | |
24 | fmode_t mode; | |
25 | struct inode vfs_inode; | |
26 | }; | |
27 | ||
28 | static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) | |
29 | { | |
30 | return list_entry(inode, struct hostfs_inode_info, vfs_inode); | |
31 | } | |
32 | ||
33 | #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_path.dentry->d_inode) | |
34 | ||
35 | static int hostfs_d_delete(struct dentry *dentry) | |
36 | { | |
37 | return 1; | |
38 | } | |
39 | ||
40 | static const struct dentry_operations hostfs_dentry_ops = { | |
41 | .d_delete = hostfs_d_delete, | |
42 | }; | |
43 | ||
44 | /* Changed in hostfs_args before the kernel starts running */ | |
45 | static char *root_ino = ""; | |
46 | static int append = 0; | |
47 | ||
48 | #define HOSTFS_SUPER_MAGIC 0x00c0ffee | |
49 | ||
50 | static const struct inode_operations hostfs_iops; | |
51 | static const struct inode_operations hostfs_dir_iops; | |
52 | static const struct inode_operations hostfs_link_iops; | |
53 | ||
54 | #ifndef MODULE | |
55 | static int __init hostfs_args(char *options, int *add) | |
56 | { | |
57 | char *ptr; | |
58 | ||
59 | ptr = strchr(options, ','); | |
60 | if (ptr != NULL) | |
61 | *ptr++ = '\0'; | |
62 | if (*options != '\0') | |
63 | root_ino = options; | |
64 | ||
65 | options = ptr; | |
66 | while (options) { | |
67 | ptr = strchr(options, ','); | |
68 | if (ptr != NULL) | |
69 | *ptr++ = '\0'; | |
70 | if (*options != '\0') { | |
71 | if (!strcmp(options, "append")) | |
72 | append = 1; | |
73 | else printf("hostfs_args - unsupported option - %s\n", | |
74 | options); | |
75 | } | |
76 | options = ptr; | |
77 | } | |
78 | return 0; | |
79 | } | |
80 | ||
81 | __uml_setup("hostfs=", hostfs_args, | |
82 | "hostfs=<root dir>,<flags>,...\n" | |
83 | " This is used to set hostfs parameters. The root directory argument\n" | |
84 | " is used to confine all hostfs mounts to within the specified directory\n" | |
85 | " tree on the host. If this isn't specified, then a user inside UML can\n" | |
86 | " mount anything on the host that's accessible to the user that's running\n" | |
87 | " it.\n" | |
88 | " The only flag currently supported is 'append', which specifies that all\n" | |
89 | " files opened by hostfs will be opened in append mode.\n\n" | |
90 | ); | |
91 | #endif | |
92 | ||
93 | static char *__dentry_name(struct dentry *dentry, char *name) | |
94 | { | |
95 | char *p = __dentry_path(dentry, name, PATH_MAX); | |
96 | char *root; | |
97 | size_t len; | |
98 | ||
99 | spin_unlock(&dcache_lock); | |
100 | ||
101 | root = dentry->d_sb->s_fs_info; | |
102 | len = strlen(root); | |
103 | if (IS_ERR(p)) { | |
104 | __putname(name); | |
105 | return NULL; | |
106 | } | |
107 | strlcpy(name, root, PATH_MAX); | |
108 | if (len > p - name) { | |
109 | __putname(name); | |
110 | return NULL; | |
111 | } | |
112 | if (p > name + len) { | |
113 | char *s = name + len; | |
114 | while ((*s++ = *p++) != '\0') | |
115 | ; | |
116 | } | |
117 | return name; | |
118 | } | |
119 | ||
120 | static char *dentry_name(struct dentry *dentry) | |
121 | { | |
122 | char *name = __getname(); | |
123 | if (!name) | |
124 | return NULL; | |
125 | ||
126 | spin_lock(&dcache_lock); | |
127 | return __dentry_name(dentry, name); /* will unlock */ | |
128 | } | |
129 | ||
130 | static char *inode_name(struct inode *ino) | |
131 | { | |
132 | struct dentry *dentry; | |
133 | char *name = __getname(); | |
134 | if (!name) | |
135 | return NULL; | |
136 | ||
137 | spin_lock(&dcache_lock); | |
138 | if (list_empty(&ino->i_dentry)) { | |
139 | spin_unlock(&dcache_lock); | |
140 | __putname(name); | |
141 | return NULL; | |
142 | } | |
143 | dentry = list_first_entry(&ino->i_dentry, struct dentry, d_alias); | |
144 | return __dentry_name(dentry, name); /* will unlock */ | |
145 | } | |
146 | ||
147 | static char *follow_link(char *link) | |
148 | { | |
149 | int len, n; | |
150 | char *name, *resolved, *end; | |
151 | ||
152 | len = 64; | |
153 | while (1) { | |
154 | n = -ENOMEM; | |
155 | name = kmalloc(len, GFP_KERNEL); | |
156 | if (name == NULL) | |
157 | goto out; | |
158 | ||
159 | n = hostfs_do_readlink(link, name, len); | |
160 | if (n < len) | |
161 | break; | |
162 | len *= 2; | |
163 | kfree(name); | |
164 | } | |
165 | if (n < 0) | |
166 | goto out_free; | |
167 | ||
168 | if (*name == '/') | |
169 | return name; | |
170 | ||
171 | end = strrchr(link, '/'); | |
172 | if (end == NULL) | |
173 | return name; | |
174 | ||
175 | *(end + 1) = '\0'; | |
176 | len = strlen(link) + strlen(name) + 1; | |
177 | ||
178 | resolved = kmalloc(len, GFP_KERNEL); | |
179 | if (resolved == NULL) { | |
180 | n = -ENOMEM; | |
181 | goto out_free; | |
182 | } | |
183 | ||
184 | sprintf(resolved, "%s%s", link, name); | |
185 | kfree(name); | |
186 | kfree(link); | |
187 | return resolved; | |
188 | ||
189 | out_free: | |
190 | kfree(name); | |
191 | out: | |
192 | return ERR_PTR(n); | |
193 | } | |
194 | ||
195 | static struct inode *hostfs_iget(struct super_block *sb) | |
196 | { | |
197 | struct inode *inode = new_inode(sb); | |
198 | if (!inode) | |
199 | return ERR_PTR(-ENOMEM); | |
200 | return inode; | |
201 | } | |
202 | ||
203 | int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) | |
204 | { | |
205 | /* | |
206 | * do_statfs uses struct statfs64 internally, but the linux kernel | |
207 | * struct statfs still has 32-bit versions for most of these fields, | |
208 | * so we convert them here | |
209 | */ | |
210 | int err; | |
211 | long long f_blocks; | |
212 | long long f_bfree; | |
213 | long long f_bavail; | |
214 | long long f_files; | |
215 | long long f_ffree; | |
216 | ||
217 | err = do_statfs(dentry->d_sb->s_fs_info, | |
218 | &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, | |
219 | &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), | |
220 | &sf->f_namelen); | |
221 | if (err) | |
222 | return err; | |
223 | sf->f_blocks = f_blocks; | |
224 | sf->f_bfree = f_bfree; | |
225 | sf->f_bavail = f_bavail; | |
226 | sf->f_files = f_files; | |
227 | sf->f_ffree = f_ffree; | |
228 | sf->f_type = HOSTFS_SUPER_MAGIC; | |
229 | return 0; | |
230 | } | |
231 | ||
232 | static struct inode *hostfs_alloc_inode(struct super_block *sb) | |
233 | { | |
234 | struct hostfs_inode_info *hi; | |
235 | ||
236 | hi = kzalloc(sizeof(*hi), GFP_KERNEL); | |
237 | if (hi == NULL) | |
238 | return NULL; | |
239 | hi->fd = -1; | |
240 | inode_init_once(&hi->vfs_inode); | |
241 | return &hi->vfs_inode; | |
242 | } | |
243 | ||
244 | static void hostfs_evict_inode(struct inode *inode) | |
245 | { | |
246 | truncate_inode_pages(&inode->i_data, 0); | |
247 | end_writeback(inode); | |
248 | if (HOSTFS_I(inode)->fd != -1) { | |
249 | close_file(&HOSTFS_I(inode)->fd); | |
250 | HOSTFS_I(inode)->fd = -1; | |
251 | } | |
252 | } | |
253 | ||
254 | static void hostfs_destroy_inode(struct inode *inode) | |
255 | { | |
256 | kfree(HOSTFS_I(inode)); | |
257 | } | |
258 | ||
259 | static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
260 | { | |
261 | const char *root_path = vfs->mnt_sb->s_fs_info; | |
262 | size_t offset = strlen(root_ino) + 1; | |
263 | ||
264 | if (strlen(root_path) > offset) | |
265 | seq_printf(seq, ",%s", root_path + offset); | |
266 | ||
267 | return 0; | |
268 | } | |
269 | ||
270 | static const struct super_operations hostfs_sbops = { | |
271 | .alloc_inode = hostfs_alloc_inode, | |
272 | .destroy_inode = hostfs_destroy_inode, | |
273 | .evict_inode = hostfs_evict_inode, | |
274 | .statfs = hostfs_statfs, | |
275 | .show_options = hostfs_show_options, | |
276 | }; | |
277 | ||
278 | int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) | |
279 | { | |
280 | void *dir; | |
281 | char *name; | |
282 | unsigned long long next, ino; | |
283 | int error, len; | |
284 | ||
285 | name = dentry_name(file->f_path.dentry); | |
286 | if (name == NULL) | |
287 | return -ENOMEM; | |
288 | dir = open_dir(name, &error); | |
289 | __putname(name); | |
290 | if (dir == NULL) | |
291 | return -error; | |
292 | next = file->f_pos; | |
293 | while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { | |
294 | error = (*filldir)(ent, name, len, file->f_pos, | |
295 | ino, DT_UNKNOWN); | |
296 | if (error) break; | |
297 | file->f_pos = next; | |
298 | } | |
299 | close_dir(dir); | |
300 | return 0; | |
301 | } | |
302 | ||
303 | int hostfs_file_open(struct inode *ino, struct file *file) | |
304 | { | |
305 | static DEFINE_MUTEX(open_mutex); | |
306 | char *name; | |
307 | fmode_t mode = 0; | |
308 | int err; | |
309 | int r = 0, w = 0, fd; | |
310 | ||
311 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); | |
312 | if ((mode & HOSTFS_I(ino)->mode) == mode) | |
313 | return 0; | |
314 | ||
315 | mode |= HOSTFS_I(ino)->mode; | |
316 | ||
317 | retry: | |
318 | if (mode & FMODE_READ) | |
319 | r = 1; | |
320 | if (mode & FMODE_WRITE) | |
321 | w = 1; | |
322 | if (w) | |
323 | r = 1; | |
324 | ||
325 | name = dentry_name(file->f_path.dentry); | |
326 | if (name == NULL) | |
327 | return -ENOMEM; | |
328 | ||
329 | fd = open_file(name, r, w, append); | |
330 | __putname(name); | |
331 | if (fd < 0) | |
332 | return fd; | |
333 | ||
334 | mutex_lock(&open_mutex); | |
335 | /* somebody else had handled it first? */ | |
336 | if ((mode & HOSTFS_I(ino)->mode) == mode) { | |
337 | mutex_unlock(&open_mutex); | |
338 | return 0; | |
339 | } | |
340 | if ((mode | HOSTFS_I(ino)->mode) != mode) { | |
341 | mode |= HOSTFS_I(ino)->mode; | |
342 | mutex_unlock(&open_mutex); | |
343 | close_file(&fd); | |
344 | goto retry; | |
345 | } | |
346 | if (HOSTFS_I(ino)->fd == -1) { | |
347 | HOSTFS_I(ino)->fd = fd; | |
348 | } else { | |
349 | err = replace_file(fd, HOSTFS_I(ino)->fd); | |
350 | close_file(&fd); | |
351 | if (err < 0) { | |
352 | mutex_unlock(&open_mutex); | |
353 | return err; | |
354 | } | |
355 | } | |
356 | HOSTFS_I(ino)->mode = mode; | |
357 | mutex_unlock(&open_mutex); | |
358 | ||
359 | return 0; | |
360 | } | |
361 | ||
362 | int hostfs_fsync(struct file *file, int datasync) | |
363 | { | |
364 | return fsync_file(HOSTFS_I(file->f_mapping->host)->fd, datasync); | |
365 | } | |
366 | ||
367 | static const struct file_operations hostfs_file_fops = { | |
368 | .llseek = generic_file_llseek, | |
369 | .read = do_sync_read, | |
370 | .splice_read = generic_file_splice_read, | |
371 | .aio_read = generic_file_aio_read, | |
372 | .aio_write = generic_file_aio_write, | |
373 | .write = do_sync_write, | |
374 | .mmap = generic_file_mmap, | |
375 | .open = hostfs_file_open, | |
376 | .release = NULL, | |
377 | .fsync = hostfs_fsync, | |
378 | }; | |
379 | ||
380 | static const struct file_operations hostfs_dir_fops = { | |
381 | .llseek = generic_file_llseek, | |
382 | .readdir = hostfs_readdir, | |
383 | .read = generic_read_dir, | |
384 | }; | |
385 | ||
386 | int hostfs_writepage(struct page *page, struct writeback_control *wbc) | |
387 | { | |
388 | struct address_space *mapping = page->mapping; | |
389 | struct inode *inode = mapping->host; | |
390 | char *buffer; | |
391 | unsigned long long base; | |
392 | int count = PAGE_CACHE_SIZE; | |
393 | int end_index = inode->i_size >> PAGE_CACHE_SHIFT; | |
394 | int err; | |
395 | ||
396 | if (page->index >= end_index) | |
397 | count = inode->i_size & (PAGE_CACHE_SIZE-1); | |
398 | ||
399 | buffer = kmap(page); | |
400 | base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; | |
401 | ||
402 | err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); | |
403 | if (err != count) { | |
404 | ClearPageUptodate(page); | |
405 | goto out; | |
406 | } | |
407 | ||
408 | if (base > inode->i_size) | |
409 | inode->i_size = base; | |
410 | ||
411 | if (PageError(page)) | |
412 | ClearPageError(page); | |
413 | err = 0; | |
414 | ||
415 | out: | |
416 | kunmap(page); | |
417 | ||
418 | unlock_page(page); | |
419 | return err; | |
420 | } | |
421 | ||
422 | int hostfs_readpage(struct file *file, struct page *page) | |
423 | { | |
424 | char *buffer; | |
425 | long long start; | |
426 | int err = 0; | |
427 | ||
428 | start = (long long) page->index << PAGE_CACHE_SHIFT; | |
429 | buffer = kmap(page); | |
430 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, | |
431 | PAGE_CACHE_SIZE); | |
432 | if (err < 0) | |
433 | goto out; | |
434 | ||
435 | memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); | |
436 | ||
437 | flush_dcache_page(page); | |
438 | SetPageUptodate(page); | |
439 | if (PageError(page)) ClearPageError(page); | |
440 | err = 0; | |
441 | out: | |
442 | kunmap(page); | |
443 | unlock_page(page); | |
444 | return err; | |
445 | } | |
446 | ||
447 | int hostfs_write_begin(struct file *file, struct address_space *mapping, | |
448 | loff_t pos, unsigned len, unsigned flags, | |
449 | struct page **pagep, void **fsdata) | |
450 | { | |
451 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
452 | ||
453 | *pagep = grab_cache_page_write_begin(mapping, index, flags); | |
454 | if (!*pagep) | |
455 | return -ENOMEM; | |
456 | return 0; | |
457 | } | |
458 | ||
459 | int hostfs_write_end(struct file *file, struct address_space *mapping, | |
460 | loff_t pos, unsigned len, unsigned copied, | |
461 | struct page *page, void *fsdata) | |
462 | { | |
463 | struct inode *inode = mapping->host; | |
464 | void *buffer; | |
465 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
466 | int err; | |
467 | ||
468 | buffer = kmap(page); | |
469 | err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); | |
470 | kunmap(page); | |
471 | ||
472 | if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) | |
473 | SetPageUptodate(page); | |
474 | ||
475 | /* | |
476 | * If err > 0, write_file has added err to pos, so we are comparing | |
477 | * i_size against the last byte written. | |
478 | */ | |
479 | if (err > 0 && (pos > inode->i_size)) | |
480 | inode->i_size = pos; | |
481 | unlock_page(page); | |
482 | page_cache_release(page); | |
483 | ||
484 | return err; | |
485 | } | |
486 | ||
487 | static const struct address_space_operations hostfs_aops = { | |
488 | .writepage = hostfs_writepage, | |
489 | .readpage = hostfs_readpage, | |
490 | .set_page_dirty = __set_page_dirty_nobuffers, | |
491 | .write_begin = hostfs_write_begin, | |
492 | .write_end = hostfs_write_end, | |
493 | }; | |
494 | ||
495 | static int read_name(struct inode *ino, char *name) | |
496 | { | |
497 | dev_t rdev; | |
498 | struct hostfs_stat st; | |
499 | int err = stat_file(name, &st, -1); | |
500 | if (err) | |
501 | return err; | |
502 | ||
503 | /* Reencode maj and min with the kernel encoding.*/ | |
504 | rdev = MKDEV(st.maj, st.min); | |
505 | ||
506 | switch (st.mode & S_IFMT) { | |
507 | case S_IFLNK: | |
508 | ino->i_op = &hostfs_link_iops; | |
509 | break; | |
510 | case S_IFDIR: | |
511 | ino->i_op = &hostfs_dir_iops; | |
512 | ino->i_fop = &hostfs_dir_fops; | |
513 | break; | |
514 | case S_IFCHR: | |
515 | case S_IFBLK: | |
516 | case S_IFIFO: | |
517 | case S_IFSOCK: | |
518 | init_special_inode(ino, st.mode & S_IFMT, rdev); | |
519 | ino->i_op = &hostfs_iops; | |
520 | break; | |
521 | ||
522 | default: | |
523 | ino->i_op = &hostfs_iops; | |
524 | ino->i_fop = &hostfs_file_fops; | |
525 | ino->i_mapping->a_ops = &hostfs_aops; | |
526 | } | |
527 | ||
528 | ino->i_ino = st.ino; | |
529 | ino->i_mode = st.mode; | |
530 | ino->i_nlink = st.nlink; | |
531 | ino->i_uid = st.uid; | |
532 | ino->i_gid = st.gid; | |
533 | ino->i_atime = st.atime; | |
534 | ino->i_mtime = st.mtime; | |
535 | ino->i_ctime = st.ctime; | |
536 | ino->i_size = st.size; | |
537 | ino->i_blocks = st.blocks; | |
538 | return 0; | |
539 | } | |
540 | ||
541 | int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, | |
542 | struct nameidata *nd) | |
543 | { | |
544 | struct inode *inode; | |
545 | char *name; | |
546 | int error, fd; | |
547 | ||
548 | inode = hostfs_iget(dir->i_sb); | |
549 | if (IS_ERR(inode)) { | |
550 | error = PTR_ERR(inode); | |
551 | goto out; | |
552 | } | |
553 | ||
554 | error = -ENOMEM; | |
555 | name = dentry_name(dentry); | |
556 | if (name == NULL) | |
557 | goto out_put; | |
558 | ||
559 | fd = file_create(name, | |
560 | mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, | |
561 | mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, | |
562 | mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); | |
563 | if (fd < 0) | |
564 | error = fd; | |
565 | else | |
566 | error = read_name(inode, name); | |
567 | ||
568 | __putname(name); | |
569 | if (error) | |
570 | goto out_put; | |
571 | ||
572 | HOSTFS_I(inode)->fd = fd; | |
573 | HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; | |
574 | d_instantiate(dentry, inode); | |
575 | return 0; | |
576 | ||
577 | out_put: | |
578 | iput(inode); | |
579 | out: | |
580 | return error; | |
581 | } | |
582 | ||
583 | struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, | |
584 | struct nameidata *nd) | |
585 | { | |
586 | struct inode *inode; | |
587 | char *name; | |
588 | int err; | |
589 | ||
590 | inode = hostfs_iget(ino->i_sb); | |
591 | if (IS_ERR(inode)) { | |
592 | err = PTR_ERR(inode); | |
593 | goto out; | |
594 | } | |
595 | ||
596 | err = -ENOMEM; | |
597 | name = dentry_name(dentry); | |
598 | if (name == NULL) | |
599 | goto out_put; | |
600 | ||
601 | err = read_name(inode, name); | |
602 | ||
603 | __putname(name); | |
604 | if (err == -ENOENT) { | |
605 | iput(inode); | |
606 | inode = NULL; | |
607 | } | |
608 | else if (err) | |
609 | goto out_put; | |
610 | ||
611 | d_add(dentry, inode); | |
612 | dentry->d_op = &hostfs_dentry_ops; | |
613 | return NULL; | |
614 | ||
615 | out_put: | |
616 | iput(inode); | |
617 | out: | |
618 | return ERR_PTR(err); | |
619 | } | |
620 | ||
621 | int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) | |
622 | { | |
623 | char *from_name, *to_name; | |
624 | int err; | |
625 | ||
626 | if ((from_name = dentry_name(from)) == NULL) | |
627 | return -ENOMEM; | |
628 | to_name = dentry_name(to); | |
629 | if (to_name == NULL) { | |
630 | __putname(from_name); | |
631 | return -ENOMEM; | |
632 | } | |
633 | err = link_file(to_name, from_name); | |
634 | __putname(from_name); | |
635 | __putname(to_name); | |
636 | return err; | |
637 | } | |
638 | ||
639 | int hostfs_unlink(struct inode *ino, struct dentry *dentry) | |
640 | { | |
641 | char *file; | |
642 | int err; | |
643 | ||
644 | if (append) | |
645 | return -EPERM; | |
646 | ||
647 | if ((file = dentry_name(dentry)) == NULL) | |
648 | return -ENOMEM; | |
649 | ||
650 | err = unlink_file(file); | |
651 | __putname(file); | |
652 | return err; | |
653 | } | |
654 | ||
655 | int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) | |
656 | { | |
657 | char *file; | |
658 | int err; | |
659 | ||
660 | if ((file = dentry_name(dentry)) == NULL) | |
661 | return -ENOMEM; | |
662 | err = make_symlink(file, to); | |
663 | __putname(file); | |
664 | return err; | |
665 | } | |
666 | ||
667 | int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) | |
668 | { | |
669 | char *file; | |
670 | int err; | |
671 | ||
672 | if ((file = dentry_name(dentry)) == NULL) | |
673 | return -ENOMEM; | |
674 | err = do_mkdir(file, mode); | |
675 | __putname(file); | |
676 | return err; | |
677 | } | |
678 | ||
679 | int hostfs_rmdir(struct inode *ino, struct dentry *dentry) | |
680 | { | |
681 | char *file; | |
682 | int err; | |
683 | ||
684 | if ((file = dentry_name(dentry)) == NULL) | |
685 | return -ENOMEM; | |
686 | err = do_rmdir(file); | |
687 | __putname(file); | |
688 | return err; | |
689 | } | |
690 | ||
691 | int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
692 | { | |
693 | struct inode *inode; | |
694 | char *name; | |
695 | int err; | |
696 | ||
697 | inode = hostfs_iget(dir->i_sb); | |
698 | if (IS_ERR(inode)) { | |
699 | err = PTR_ERR(inode); | |
700 | goto out; | |
701 | } | |
702 | ||
703 | err = -ENOMEM; | |
704 | name = dentry_name(dentry); | |
705 | if (name == NULL) | |
706 | goto out_put; | |
707 | ||
708 | init_special_inode(inode, mode, dev); | |
709 | err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); | |
710 | if (!err) | |
711 | goto out_free; | |
712 | ||
713 | err = read_name(inode, name); | |
714 | __putname(name); | |
715 | if (err) | |
716 | goto out_put; | |
717 | if (err) | |
718 | goto out_put; | |
719 | ||
720 | d_instantiate(dentry, inode); | |
721 | return 0; | |
722 | ||
723 | out_free: | |
724 | __putname(name); | |
725 | out_put: | |
726 | iput(inode); | |
727 | out: | |
728 | return err; | |
729 | } | |
730 | ||
731 | int hostfs_rename(struct inode *from_ino, struct dentry *from, | |
732 | struct inode *to_ino, struct dentry *to) | |
733 | { | |
734 | char *from_name, *to_name; | |
735 | int err; | |
736 | ||
737 | if ((from_name = dentry_name(from)) == NULL) | |
738 | return -ENOMEM; | |
739 | if ((to_name = dentry_name(to)) == NULL) { | |
740 | __putname(from_name); | |
741 | return -ENOMEM; | |
742 | } | |
743 | err = rename_file(from_name, to_name); | |
744 | __putname(from_name); | |
745 | __putname(to_name); | |
746 | return err; | |
747 | } | |
748 | ||
749 | int hostfs_permission(struct inode *ino, int desired) | |
750 | { | |
751 | char *name; | |
752 | int r = 0, w = 0, x = 0, err; | |
753 | ||
754 | if (desired & MAY_READ) r = 1; | |
755 | if (desired & MAY_WRITE) w = 1; | |
756 | if (desired & MAY_EXEC) x = 1; | |
757 | name = inode_name(ino); | |
758 | if (name == NULL) | |
759 | return -ENOMEM; | |
760 | ||
761 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || | |
762 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) | |
763 | err = 0; | |
764 | else | |
765 | err = access_file(name, r, w, x); | |
766 | __putname(name); | |
767 | if (!err) | |
768 | err = generic_permission(ino, desired, NULL); | |
769 | return err; | |
770 | } | |
771 | ||
772 | int hostfs_setattr(struct dentry *dentry, struct iattr *attr) | |
773 | { | |
774 | struct inode *inode = dentry->d_inode; | |
775 | struct hostfs_iattr attrs; | |
776 | char *name; | |
777 | int err; | |
778 | ||
779 | int fd = HOSTFS_I(inode)->fd; | |
780 | ||
781 | err = inode_change_ok(inode, attr); | |
782 | if (err) | |
783 | return err; | |
784 | ||
785 | if (append) | |
786 | attr->ia_valid &= ~ATTR_SIZE; | |
787 | ||
788 | attrs.ia_valid = 0; | |
789 | if (attr->ia_valid & ATTR_MODE) { | |
790 | attrs.ia_valid |= HOSTFS_ATTR_MODE; | |
791 | attrs.ia_mode = attr->ia_mode; | |
792 | } | |
793 | if (attr->ia_valid & ATTR_UID) { | |
794 | attrs.ia_valid |= HOSTFS_ATTR_UID; | |
795 | attrs.ia_uid = attr->ia_uid; | |
796 | } | |
797 | if (attr->ia_valid & ATTR_GID) { | |
798 | attrs.ia_valid |= HOSTFS_ATTR_GID; | |
799 | attrs.ia_gid = attr->ia_gid; | |
800 | } | |
801 | if (attr->ia_valid & ATTR_SIZE) { | |
802 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; | |
803 | attrs.ia_size = attr->ia_size; | |
804 | } | |
805 | if (attr->ia_valid & ATTR_ATIME) { | |
806 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; | |
807 | attrs.ia_atime = attr->ia_atime; | |
808 | } | |
809 | if (attr->ia_valid & ATTR_MTIME) { | |
810 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; | |
811 | attrs.ia_mtime = attr->ia_mtime; | |
812 | } | |
813 | if (attr->ia_valid & ATTR_CTIME) { | |
814 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; | |
815 | attrs.ia_ctime = attr->ia_ctime; | |
816 | } | |
817 | if (attr->ia_valid & ATTR_ATIME_SET) { | |
818 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; | |
819 | } | |
820 | if (attr->ia_valid & ATTR_MTIME_SET) { | |
821 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; | |
822 | } | |
823 | name = dentry_name(dentry); | |
824 | if (name == NULL) | |
825 | return -ENOMEM; | |
826 | err = set_attr(name, &attrs, fd); | |
827 | __putname(name); | |
828 | if (err) | |
829 | return err; | |
830 | ||
831 | if ((attr->ia_valid & ATTR_SIZE) && | |
832 | attr->ia_size != i_size_read(inode)) { | |
833 | int error; | |
834 | ||
835 | error = vmtruncate(inode, attr->ia_size); | |
836 | if (err) | |
837 | return err; | |
838 | } | |
839 | ||
840 | setattr_copy(inode, attr); | |
841 | mark_inode_dirty(inode); | |
842 | return 0; | |
843 | } | |
844 | ||
845 | static const struct inode_operations hostfs_iops = { | |
846 | .create = hostfs_create, | |
847 | .link = hostfs_link, | |
848 | .unlink = hostfs_unlink, | |
849 | .symlink = hostfs_symlink, | |
850 | .mkdir = hostfs_mkdir, | |
851 | .rmdir = hostfs_rmdir, | |
852 | .mknod = hostfs_mknod, | |
853 | .rename = hostfs_rename, | |
854 | .permission = hostfs_permission, | |
855 | .setattr = hostfs_setattr, | |
856 | }; | |
857 | ||
858 | static const struct inode_operations hostfs_dir_iops = { | |
859 | .create = hostfs_create, | |
860 | .lookup = hostfs_lookup, | |
861 | .link = hostfs_link, | |
862 | .unlink = hostfs_unlink, | |
863 | .symlink = hostfs_symlink, | |
864 | .mkdir = hostfs_mkdir, | |
865 | .rmdir = hostfs_rmdir, | |
866 | .mknod = hostfs_mknod, | |
867 | .rename = hostfs_rename, | |
868 | .permission = hostfs_permission, | |
869 | .setattr = hostfs_setattr, | |
870 | }; | |
871 | ||
872 | static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd) | |
873 | { | |
874 | char *link = __getname(); | |
875 | if (link) { | |
876 | char *path = dentry_name(dentry); | |
877 | int err = -ENOMEM; | |
878 | if (path) { | |
879 | err = hostfs_do_readlink(path, link, PATH_MAX); | |
880 | if (err == PATH_MAX) | |
881 | err = -E2BIG; | |
882 | __putname(path); | |
883 | } | |
884 | if (err < 0) { | |
885 | __putname(link); | |
886 | link = ERR_PTR(err); | |
887 | } | |
888 | } else { | |
889 | link = ERR_PTR(-ENOMEM); | |
890 | } | |
891 | ||
892 | nd_set_link(nd, link); | |
893 | return NULL; | |
894 | } | |
895 | ||
896 | static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) | |
897 | { | |
898 | char *s = nd_get_link(nd); | |
899 | if (!IS_ERR(s)) | |
900 | __putname(s); | |
901 | } | |
902 | ||
903 | static const struct inode_operations hostfs_link_iops = { | |
904 | .readlink = generic_readlink, | |
905 | .follow_link = hostfs_follow_link, | |
906 | .put_link = hostfs_put_link, | |
907 | }; | |
908 | ||
909 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) | |
910 | { | |
911 | struct inode *root_inode; | |
912 | char *host_root_path, *req_root = d; | |
913 | int err; | |
914 | ||
915 | sb->s_blocksize = 1024; | |
916 | sb->s_blocksize_bits = 10; | |
917 | sb->s_magic = HOSTFS_SUPER_MAGIC; | |
918 | sb->s_op = &hostfs_sbops; | |
919 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
920 | ||
921 | /* NULL is printed as <NULL> by sprintf: avoid that. */ | |
922 | if (req_root == NULL) | |
923 | req_root = ""; | |
924 | ||
925 | err = -ENOMEM; | |
926 | sb->s_fs_info = host_root_path = | |
927 | kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); | |
928 | if (host_root_path == NULL) | |
929 | goto out; | |
930 | ||
931 | sprintf(host_root_path, "%s/%s", root_ino, req_root); | |
932 | ||
933 | root_inode = new_inode(sb); | |
934 | if (!root_inode) | |
935 | goto out; | |
936 | ||
937 | err = read_name(root_inode, host_root_path); | |
938 | if (err) | |
939 | goto out_put; | |
940 | ||
941 | if (S_ISLNK(root_inode->i_mode)) { | |
942 | char *name = follow_link(host_root_path); | |
943 | if (IS_ERR(name)) | |
944 | err = PTR_ERR(name); | |
945 | else | |
946 | err = read_name(root_inode, name); | |
947 | kfree(name); | |
948 | if (err) | |
949 | goto out_put; | |
950 | } | |
951 | ||
952 | err = -ENOMEM; | |
953 | sb->s_root = d_alloc_root(root_inode); | |
954 | if (sb->s_root == NULL) | |
955 | goto out_put; | |
956 | ||
957 | return 0; | |
958 | ||
959 | out_put: | |
960 | iput(root_inode); | |
961 | out: | |
962 | return err; | |
963 | } | |
964 | ||
965 | static struct dentry *hostfs_read_sb(struct file_system_type *type, | |
966 | int flags, const char *dev_name, | |
967 | void *data) | |
968 | { | |
969 | return mount_nodev(type, flags, data, hostfs_fill_sb_common); | |
970 | } | |
971 | ||
972 | static void hostfs_kill_sb(struct super_block *s) | |
973 | { | |
974 | kill_anon_super(s); | |
975 | kfree(s->s_fs_info); | |
976 | } | |
977 | ||
978 | static struct file_system_type hostfs_type = { | |
979 | .owner = THIS_MODULE, | |
980 | .name = "hostfs", | |
981 | .mount = hostfs_read_sb, | |
982 | .kill_sb = hostfs_kill_sb, | |
983 | .fs_flags = 0, | |
984 | }; | |
985 | ||
986 | static int __init init_hostfs(void) | |
987 | { | |
988 | return register_filesystem(&hostfs_type); | |
989 | } | |
990 | ||
991 | static void __exit exit_hostfs(void) | |
992 | { | |
993 | unregister_filesystem(&hostfs_type); | |
994 | } | |
995 | ||
996 | module_init(init_hostfs) | |
997 | module_exit(exit_hostfs) | |
998 | MODULE_LICENSE("GPL"); |