Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
f1adc05e | 2 | * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
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 | ||
1da177e4 | 9 | #include <linux/fs.h> |
1da177e4 | 10 | #include <linux/module.h> |
84b3db04 | 11 | #include <linux/mm.h> |
1da177e4 | 12 | #include <linux/pagemap.h> |
1da177e4 | 13 | #include <linux/statfs.h> |
dd2cc4df | 14 | #include <linux/seq_file.h> |
6966a977 | 15 | #include <linux/mount.h> |
1da177e4 | 16 | #include "hostfs.h" |
1da177e4 | 17 | #include "init.h" |
84b3db04 | 18 | #include "kern.h" |
1da177e4 LT |
19 | |
20 | struct hostfs_inode_info { | |
21 | char *host_filename; | |
22 | int fd; | |
aeb5d727 | 23 | fmode_t mode; |
1da177e4 LT |
24 | struct inode vfs_inode; |
25 | }; | |
26 | ||
27 | static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) | |
28 | { | |
f1adc05e | 29 | return list_entry(inode, struct hostfs_inode_info, vfs_inode); |
1da177e4 LT |
30 | } |
31 | ||
680b0da9 | 32 | #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_path.dentry->d_inode) |
1da177e4 LT |
33 | |
34 | int hostfs_d_delete(struct dentry *dentry) | |
35 | { | |
f1adc05e | 36 | return 1; |
1da177e4 LT |
37 | } |
38 | ||
39 | struct dentry_operations hostfs_dentry_ops = { | |
40 | .d_delete = hostfs_d_delete, | |
41 | }; | |
42 | ||
43 | /* Changed in hostfs_args before the kernel starts running */ | |
a6eb0be6 | 44 | static char *root_ino = ""; |
1da177e4 LT |
45 | static int append = 0; |
46 | ||
47 | #define HOSTFS_SUPER_MAGIC 0x00c0ffee | |
48 | ||
92e1d5be AV |
49 | static const struct inode_operations hostfs_iops; |
50 | static const struct inode_operations hostfs_dir_iops; | |
f5e54d6e | 51 | static const struct address_space_operations hostfs_link_aops; |
1da177e4 LT |
52 | |
53 | #ifndef MODULE | |
54 | static int __init hostfs_args(char *options, int *add) | |
55 | { | |
56 | char *ptr; | |
57 | ||
58 | ptr = strchr(options, ','); | |
84b3db04 | 59 | if (ptr != NULL) |
1da177e4 | 60 | *ptr++ = '\0'; |
84b3db04 | 61 | if (*options != '\0') |
1da177e4 LT |
62 | root_ino = options; |
63 | ||
64 | options = ptr; | |
84b3db04 | 65 | while (options) { |
1da177e4 | 66 | ptr = strchr(options, ','); |
84b3db04 | 67 | if (ptr != NULL) |
1da177e4 | 68 | *ptr++ = '\0'; |
84b3db04 JD |
69 | if (*options != '\0') { |
70 | if (!strcmp(options, "append")) | |
1da177e4 LT |
71 | append = 1; |
72 | else printf("hostfs_args - unsupported option - %s\n", | |
73 | options); | |
74 | } | |
75 | options = ptr; | |
76 | } | |
f1adc05e | 77 | return 0; |
1da177e4 LT |
78 | } |
79 | ||
80 | __uml_setup("hostfs=", hostfs_args, | |
81 | "hostfs=<root dir>,<flags>,...\n" | |
82 | " This is used to set hostfs parameters. The root directory argument\n" | |
83 | " is used to confine all hostfs mounts to within the specified directory\n" | |
84 | " tree on the host. If this isn't specified, then a user inside UML can\n" | |
85 | " mount anything on the host that's accessible to the user that's running\n" | |
86 | " it.\n" | |
87 | " The only flag currently supported is 'append', which specifies that all\n" | |
88 | " files opened by hostfs will be opened in append mode.\n\n" | |
89 | ); | |
90 | #endif | |
91 | ||
92 | static char *dentry_name(struct dentry *dentry, int extra) | |
93 | { | |
94 | struct dentry *parent; | |
95 | char *root, *name; | |
96 | int len; | |
97 | ||
98 | len = 0; | |
99 | parent = dentry; | |
84b3db04 | 100 | while (parent->d_parent != parent) { |
1da177e4 LT |
101 | len += parent->d_name.len + 1; |
102 | parent = parent->d_parent; | |
103 | } | |
104 | ||
105 | root = HOSTFS_I(parent->d_inode)->host_filename; | |
106 | len += strlen(root); | |
107 | name = kmalloc(len + extra + 1, GFP_KERNEL); | |
84b3db04 | 108 | if (name == NULL) |
f1adc05e | 109 | return NULL; |
1da177e4 LT |
110 | |
111 | name[len] = '\0'; | |
112 | parent = dentry; | |
84b3db04 | 113 | while (parent->d_parent != parent) { |
1da177e4 LT |
114 | len -= parent->d_name.len + 1; |
115 | name[len] = '/'; | |
116 | strncpy(&name[len + 1], parent->d_name.name, | |
117 | parent->d_name.len); | |
118 | parent = parent->d_parent; | |
119 | } | |
120 | strncpy(name, root, strlen(root)); | |
f1adc05e | 121 | return name; |
1da177e4 LT |
122 | } |
123 | ||
124 | static char *inode_name(struct inode *ino, int extra) | |
125 | { | |
126 | struct dentry *dentry; | |
127 | ||
128 | dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); | |
f1adc05e | 129 | return dentry_name(dentry, extra); |
1da177e4 LT |
130 | } |
131 | ||
132 | static int read_name(struct inode *ino, char *name) | |
133 | { | |
84b3db04 JD |
134 | /* |
135 | * The non-int inode fields are copied into ints by stat_file and | |
1da177e4 LT |
136 | * then copied into the inode because passing the actual pointers |
137 | * in and having them treated as int * breaks on big-endian machines | |
138 | */ | |
139 | int err; | |
140 | int i_mode, i_nlink, i_blksize; | |
141 | unsigned long long i_size; | |
142 | unsigned long long i_ino; | |
143 | unsigned long long i_blocks; | |
144 | ||
145 | err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, | |
146 | &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, | |
5822b7fa | 147 | &ino->i_ctime, &i_blksize, &i_blocks, -1); |
84b3db04 | 148 | if (err) |
f1adc05e | 149 | return err; |
1da177e4 LT |
150 | |
151 | ino->i_ino = i_ino; | |
152 | ino->i_mode = i_mode; | |
153 | ino->i_nlink = i_nlink; | |
154 | ino->i_size = i_size; | |
1da177e4 | 155 | ino->i_blocks = i_blocks; |
f1adc05e | 156 | return 0; |
1da177e4 LT |
157 | } |
158 | ||
159 | static char *follow_link(char *link) | |
160 | { | |
161 | int len, n; | |
162 | char *name, *resolved, *end; | |
163 | ||
164 | len = 64; | |
84b3db04 | 165 | while (1) { |
1da177e4 LT |
166 | n = -ENOMEM; |
167 | name = kmalloc(len, GFP_KERNEL); | |
84b3db04 | 168 | if (name == NULL) |
1da177e4 LT |
169 | goto out; |
170 | ||
ea7e743e | 171 | n = hostfs_do_readlink(link, name, len); |
84b3db04 | 172 | if (n < len) |
1da177e4 LT |
173 | break; |
174 | len *= 2; | |
175 | kfree(name); | |
176 | } | |
84b3db04 | 177 | if (n < 0) |
1da177e4 LT |
178 | goto out_free; |
179 | ||
84b3db04 | 180 | if (*name == '/') |
f1adc05e | 181 | return name; |
1da177e4 LT |
182 | |
183 | end = strrchr(link, '/'); | |
84b3db04 | 184 | if (end == NULL) |
f1adc05e | 185 | return name; |
1da177e4 LT |
186 | |
187 | *(end + 1) = '\0'; | |
188 | len = strlen(link) + strlen(name) + 1; | |
189 | ||
190 | resolved = kmalloc(len, GFP_KERNEL); | |
84b3db04 | 191 | if (resolved == NULL) { |
1da177e4 LT |
192 | n = -ENOMEM; |
193 | goto out_free; | |
194 | } | |
195 | ||
196 | sprintf(resolved, "%s%s", link, name); | |
197 | kfree(name); | |
198 | kfree(link); | |
f1adc05e | 199 | return resolved; |
1da177e4 LT |
200 | |
201 | out_free: | |
202 | kfree(name); | |
203 | out: | |
f1adc05e | 204 | return ERR_PTR(n); |
1da177e4 LT |
205 | } |
206 | ||
0a370e5d | 207 | static int hostfs_read_inode(struct inode *ino) |
1da177e4 LT |
208 | { |
209 | char *name; | |
210 | int err = 0; | |
211 | ||
84b3db04 JD |
212 | /* |
213 | * Unfortunately, we are called from iget() when we don't have a dentry | |
1da177e4 LT |
214 | * allocated yet. |
215 | */ | |
84b3db04 | 216 | if (list_empty(&ino->i_dentry)) |
1da177e4 LT |
217 | goto out; |
218 | ||
219 | err = -ENOMEM; | |
220 | name = inode_name(ino, 0); | |
84b3db04 | 221 | if (name == NULL) |
1da177e4 LT |
222 | goto out; |
223 | ||
84b3db04 | 224 | if (file_type(name, NULL, NULL) == OS_TYPE_SYMLINK) { |
1da177e4 | 225 | name = follow_link(name); |
84b3db04 | 226 | if (IS_ERR(name)) { |
1da177e4 LT |
227 | err = PTR_ERR(name); |
228 | goto out; | |
229 | } | |
230 | } | |
231 | ||
232 | err = read_name(ino, name); | |
233 | kfree(name); | |
234 | out: | |
f1adc05e | 235 | return err; |
1da177e4 LT |
236 | } |
237 | ||
0a370e5d DH |
238 | static struct inode *hostfs_iget(struct super_block *sb) |
239 | { | |
240 | struct inode *inode; | |
241 | long ret; | |
242 | ||
243 | inode = iget_locked(sb, 0); | |
244 | if (!inode) | |
245 | return ERR_PTR(-ENOMEM); | |
246 | if (inode->i_state & I_NEW) { | |
247 | ret = hostfs_read_inode(inode); | |
248 | if (ret < 0) { | |
249 | iget_failed(inode); | |
250 | return ERR_PTR(ret); | |
251 | } | |
252 | unlock_new_inode(inode); | |
253 | } | |
254 | return inode; | |
255 | } | |
256 | ||
726c3342 | 257 | int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) |
1da177e4 | 258 | { |
84b3db04 JD |
259 | /* |
260 | * do_statfs uses struct statfs64 internally, but the linux kernel | |
1da177e4 LT |
261 | * struct statfs still has 32-bit versions for most of these fields, |
262 | * so we convert them here | |
263 | */ | |
264 | int err; | |
265 | long long f_blocks; | |
266 | long long f_bfree; | |
267 | long long f_bavail; | |
268 | long long f_files; | |
269 | long long f_ffree; | |
270 | ||
726c3342 | 271 | err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename, |
1da177e4 LT |
272 | &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, |
273 | &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), | |
274 | &sf->f_namelen, sf->f_spare); | |
84b3db04 | 275 | if (err) |
f1adc05e | 276 | return err; |
1da177e4 LT |
277 | sf->f_blocks = f_blocks; |
278 | sf->f_bfree = f_bfree; | |
279 | sf->f_bavail = f_bavail; | |
280 | sf->f_files = f_files; | |
281 | sf->f_ffree = f_ffree; | |
282 | sf->f_type = HOSTFS_SUPER_MAGIC; | |
f1adc05e | 283 | return 0; |
1da177e4 LT |
284 | } |
285 | ||
286 | static struct inode *hostfs_alloc_inode(struct super_block *sb) | |
287 | { | |
288 | struct hostfs_inode_info *hi; | |
289 | ||
290 | hi = kmalloc(sizeof(*hi), GFP_KERNEL); | |
84b3db04 | 291 | if (hi == NULL) |
f1adc05e | 292 | return NULL; |
1da177e4 LT |
293 | |
294 | *hi = ((struct hostfs_inode_info) { .host_filename = NULL, | |
295 | .fd = -1, | |
296 | .mode = 0 }); | |
297 | inode_init_once(&hi->vfs_inode); | |
f1adc05e | 298 | return &hi->vfs_inode; |
1da177e4 LT |
299 | } |
300 | ||
301 | static void hostfs_delete_inode(struct inode *inode) | |
302 | { | |
fef26658 | 303 | truncate_inode_pages(&inode->i_data, 0); |
84b3db04 | 304 | if (HOSTFS_I(inode)->fd != -1) { |
1da177e4 LT |
305 | close_file(&HOSTFS_I(inode)->fd); |
306 | HOSTFS_I(inode)->fd = -1; | |
307 | } | |
308 | clear_inode(inode); | |
309 | } | |
310 | ||
311 | static void hostfs_destroy_inode(struct inode *inode) | |
312 | { | |
f99d49ad | 313 | kfree(HOSTFS_I(inode)->host_filename); |
1da177e4 | 314 | |
84b3db04 JD |
315 | /* |
316 | * XXX: This should not happen, probably. The check is here for | |
317 | * additional safety. | |
318 | */ | |
319 | if (HOSTFS_I(inode)->fd != -1) { | |
1da177e4 LT |
320 | close_file(&HOSTFS_I(inode)->fd); |
321 | printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); | |
322 | } | |
323 | ||
324 | kfree(HOSTFS_I(inode)); | |
325 | } | |
326 | ||
dd2cc4df MS |
327 | static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) |
328 | { | |
329 | struct inode *root = vfs->mnt_sb->s_root->d_inode; | |
330 | const char *root_path = HOSTFS_I(root)->host_filename; | |
331 | size_t offset = strlen(root_ino) + 1; | |
332 | ||
333 | if (strlen(root_path) > offset) | |
334 | seq_printf(seq, ",%s", root_path + offset); | |
335 | ||
336 | return 0; | |
337 | } | |
338 | ||
ee9b6d61 | 339 | static const struct super_operations hostfs_sbops = { |
1da177e4 LT |
340 | .alloc_inode = hostfs_alloc_inode, |
341 | .drop_inode = generic_delete_inode, | |
342 | .delete_inode = hostfs_delete_inode, | |
343 | .destroy_inode = hostfs_destroy_inode, | |
1da177e4 | 344 | .statfs = hostfs_statfs, |
dd2cc4df | 345 | .show_options = hostfs_show_options, |
1da177e4 LT |
346 | }; |
347 | ||
348 | int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) | |
349 | { | |
350 | void *dir; | |
351 | char *name; | |
352 | unsigned long long next, ino; | |
353 | int error, len; | |
354 | ||
680b0da9 | 355 | name = dentry_name(file->f_path.dentry, 0); |
84b3db04 | 356 | if (name == NULL) |
f1adc05e | 357 | return -ENOMEM; |
1da177e4 LT |
358 | dir = open_dir(name, &error); |
359 | kfree(name); | |
84b3db04 | 360 | if (dir == NULL) |
f1adc05e | 361 | return -error; |
1da177e4 | 362 | next = file->f_pos; |
84b3db04 | 363 | while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { |
1da177e4 LT |
364 | error = (*filldir)(ent, name, len, file->f_pos, |
365 | ino, DT_UNKNOWN); | |
84b3db04 | 366 | if (error) break; |
1da177e4 LT |
367 | file->f_pos = next; |
368 | } | |
369 | close_dir(dir); | |
f1adc05e | 370 | return 0; |
1da177e4 LT |
371 | } |
372 | ||
373 | int hostfs_file_open(struct inode *ino, struct file *file) | |
374 | { | |
375 | char *name; | |
aeb5d727 AV |
376 | fmode_t mode = 0; |
377 | int r = 0, w = 0, fd; | |
1da177e4 LT |
378 | |
379 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); | |
84b3db04 | 380 | if ((mode & HOSTFS_I(ino)->mode) == mode) |
f1adc05e | 381 | return 0; |
1da177e4 | 382 | |
84b3db04 JD |
383 | /* |
384 | * The file may already have been opened, but with the wrong access, | |
1da177e4 LT |
385 | * so this resets things and reopens the file with the new access. |
386 | */ | |
84b3db04 | 387 | if (HOSTFS_I(ino)->fd != -1) { |
1da177e4 LT |
388 | close_file(&HOSTFS_I(ino)->fd); |
389 | HOSTFS_I(ino)->fd = -1; | |
390 | } | |
391 | ||
392 | HOSTFS_I(ino)->mode |= mode; | |
84b3db04 | 393 | if (HOSTFS_I(ino)->mode & FMODE_READ) |
1da177e4 | 394 | r = 1; |
84b3db04 | 395 | if (HOSTFS_I(ino)->mode & FMODE_WRITE) |
1da177e4 | 396 | w = 1; |
84b3db04 | 397 | if (w) |
1da177e4 LT |
398 | r = 1; |
399 | ||
680b0da9 | 400 | name = dentry_name(file->f_path.dentry, 0); |
84b3db04 | 401 | if (name == NULL) |
f1adc05e | 402 | return -ENOMEM; |
1da177e4 LT |
403 | |
404 | fd = open_file(name, r, w, append); | |
405 | kfree(name); | |
84b3db04 | 406 | if (fd < 0) |
f1adc05e | 407 | return fd; |
1da177e4 LT |
408 | FILE_HOSTFS_I(file)->fd = fd; |
409 | ||
f1adc05e | 410 | return 0; |
1da177e4 LT |
411 | } |
412 | ||
413 | int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync) | |
414 | { | |
a2d76bd8 | 415 | return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync); |
1da177e4 LT |
416 | } |
417 | ||
4b6f5d20 | 418 | static const struct file_operations hostfs_file_fops = { |
1da177e4 | 419 | .llseek = generic_file_llseek, |
543ade1f | 420 | .read = do_sync_read, |
5ffc4ef4 | 421 | .splice_read = generic_file_splice_read, |
1da177e4 LT |
422 | .aio_read = generic_file_aio_read, |
423 | .aio_write = generic_file_aio_write, | |
543ade1f | 424 | .write = do_sync_write, |
1da177e4 LT |
425 | .mmap = generic_file_mmap, |
426 | .open = hostfs_file_open, | |
427 | .release = NULL, | |
428 | .fsync = hostfs_fsync, | |
429 | }; | |
430 | ||
4b6f5d20 | 431 | static const struct file_operations hostfs_dir_fops = { |
1da177e4 LT |
432 | .llseek = generic_file_llseek, |
433 | .readdir = hostfs_readdir, | |
434 | .read = generic_read_dir, | |
435 | }; | |
436 | ||
437 | int hostfs_writepage(struct page *page, struct writeback_control *wbc) | |
438 | { | |
439 | struct address_space *mapping = page->mapping; | |
440 | struct inode *inode = mapping->host; | |
441 | char *buffer; | |
442 | unsigned long long base; | |
443 | int count = PAGE_CACHE_SIZE; | |
444 | int end_index = inode->i_size >> PAGE_CACHE_SHIFT; | |
445 | int err; | |
446 | ||
447 | if (page->index >= end_index) | |
448 | count = inode->i_size & (PAGE_CACHE_SIZE-1); | |
449 | ||
450 | buffer = kmap(page); | |
451 | base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; | |
452 | ||
453 | err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); | |
84b3db04 | 454 | if (err != count) { |
1da177e4 LT |
455 | ClearPageUptodate(page); |
456 | goto out; | |
457 | } | |
458 | ||
459 | if (base > inode->i_size) | |
460 | inode->i_size = base; | |
461 | ||
462 | if (PageError(page)) | |
463 | ClearPageError(page); | |
464 | err = 0; | |
465 | ||
466 | out: | |
467 | kunmap(page); | |
468 | ||
469 | unlock_page(page); | |
470 | return err; | |
471 | } | |
472 | ||
473 | int hostfs_readpage(struct file *file, struct page *page) | |
474 | { | |
475 | char *buffer; | |
476 | long long start; | |
477 | int err = 0; | |
478 | ||
479 | start = (long long) page->index << PAGE_CACHE_SHIFT; | |
480 | buffer = kmap(page); | |
481 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, | |
482 | PAGE_CACHE_SIZE); | |
84b3db04 JD |
483 | if (err < 0) |
484 | goto out; | |
1da177e4 LT |
485 | |
486 | memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); | |
487 | ||
488 | flush_dcache_page(page); | |
489 | SetPageUptodate(page); | |
490 | if (PageError(page)) ClearPageError(page); | |
491 | err = 0; | |
492 | out: | |
493 | kunmap(page); | |
494 | unlock_page(page); | |
f1adc05e | 495 | return err; |
1da177e4 LT |
496 | } |
497 | ||
ae361ff4 NP |
498 | int hostfs_write_begin(struct file *file, struct address_space *mapping, |
499 | loff_t pos, unsigned len, unsigned flags, | |
500 | struct page **pagep, void **fsdata) | |
1da177e4 | 501 | { |
ae361ff4 | 502 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
1da177e4 | 503 | |
54566b2c | 504 | *pagep = grab_cache_page_write_begin(mapping, index, flags); |
ae361ff4 NP |
505 | if (!*pagep) |
506 | return -ENOMEM; | |
507 | return 0; | |
1da177e4 LT |
508 | } |
509 | ||
ae361ff4 NP |
510 | int hostfs_write_end(struct file *file, struct address_space *mapping, |
511 | loff_t pos, unsigned len, unsigned copied, | |
512 | struct page *page, void *fsdata) | |
1da177e4 | 513 | { |
1da177e4 | 514 | struct inode *inode = mapping->host; |
ae361ff4 NP |
515 | void *buffer; |
516 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
517 | int err; | |
1da177e4 | 518 | |
1da177e4 | 519 | buffer = kmap(page); |
ae361ff4 NP |
520 | err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); |
521 | kunmap(page); | |
30f04a4e | 522 | |
ae361ff4 NP |
523 | if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) |
524 | SetPageUptodate(page); | |
30f04a4e | 525 | |
84b3db04 JD |
526 | /* |
527 | * If err > 0, write_file has added err to pos, so we are comparing | |
ae361ff4 NP |
528 | * i_size against the last byte written. |
529 | */ | |
530 | if (err > 0 && (pos > inode->i_size)) | |
531 | inode->i_size = pos; | |
532 | unlock_page(page); | |
533 | page_cache_release(page); | |
1da177e4 | 534 | |
f1adc05e | 535 | return err; |
1da177e4 LT |
536 | } |
537 | ||
f5e54d6e | 538 | static const struct address_space_operations hostfs_aops = { |
1da177e4 LT |
539 | .writepage = hostfs_writepage, |
540 | .readpage = hostfs_readpage, | |
ffa0aea6 | 541 | .set_page_dirty = __set_page_dirty_nobuffers, |
ae361ff4 NP |
542 | .write_begin = hostfs_write_begin, |
543 | .write_end = hostfs_write_end, | |
1da177e4 LT |
544 | }; |
545 | ||
546 | static int init_inode(struct inode *inode, struct dentry *dentry) | |
547 | { | |
548 | char *name; | |
549 | int type, err = -ENOMEM; | |
550 | int maj, min; | |
551 | dev_t rdev = 0; | |
552 | ||
84b3db04 | 553 | if (dentry) { |
1da177e4 | 554 | name = dentry_name(dentry, 0); |
84b3db04 | 555 | if (name == NULL) |
1da177e4 LT |
556 | goto out; |
557 | type = file_type(name, &maj, &min); | |
84b3db04 | 558 | /* Reencode maj and min with the kernel encoding.*/ |
1da177e4 LT |
559 | rdev = MKDEV(maj, min); |
560 | kfree(name); | |
561 | } | |
562 | else type = OS_TYPE_DIR; | |
563 | ||
564 | err = 0; | |
84b3db04 | 565 | if (type == OS_TYPE_SYMLINK) |
1da177e4 | 566 | inode->i_op = &page_symlink_inode_operations; |
84b3db04 | 567 | else if (type == OS_TYPE_DIR) |
1da177e4 LT |
568 | inode->i_op = &hostfs_dir_iops; |
569 | else inode->i_op = &hostfs_iops; | |
570 | ||
84b3db04 | 571 | if (type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops; |
1da177e4 LT |
572 | else inode->i_fop = &hostfs_file_fops; |
573 | ||
84b3db04 | 574 | if (type == OS_TYPE_SYMLINK) |
1da177e4 LT |
575 | inode->i_mapping->a_ops = &hostfs_link_aops; |
576 | else inode->i_mapping->a_ops = &hostfs_aops; | |
577 | ||
578 | switch (type) { | |
579 | case OS_TYPE_CHARDEV: | |
580 | init_special_inode(inode, S_IFCHR, rdev); | |
581 | break; | |
582 | case OS_TYPE_BLOCKDEV: | |
583 | init_special_inode(inode, S_IFBLK, rdev); | |
584 | break; | |
585 | case OS_TYPE_FIFO: | |
586 | init_special_inode(inode, S_IFIFO, 0); | |
587 | break; | |
588 | case OS_TYPE_SOCK: | |
589 | init_special_inode(inode, S_IFSOCK, 0); | |
590 | break; | |
591 | } | |
592 | out: | |
f1adc05e | 593 | return err; |
1da177e4 LT |
594 | } |
595 | ||
596 | int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, | |
84b3db04 | 597 | struct nameidata *nd) |
1da177e4 LT |
598 | { |
599 | struct inode *inode; | |
600 | char *name; | |
601 | int error, fd; | |
602 | ||
0a370e5d DH |
603 | inode = hostfs_iget(dir->i_sb); |
604 | if (IS_ERR(inode)) { | |
605 | error = PTR_ERR(inode); | |
84b3db04 | 606 | goto out; |
0a370e5d | 607 | } |
1da177e4 LT |
608 | |
609 | error = init_inode(inode, dentry); | |
84b3db04 | 610 | if (error) |
1da177e4 LT |
611 | goto out_put; |
612 | ||
613 | error = -ENOMEM; | |
614 | name = dentry_name(dentry, 0); | |
84b3db04 | 615 | if (name == NULL) |
1da177e4 LT |
616 | goto out_put; |
617 | ||
618 | fd = file_create(name, | |
619 | mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, | |
620 | mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, | |
621 | mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); | |
84b3db04 | 622 | if (fd < 0) |
1da177e4 LT |
623 | error = fd; |
624 | else error = read_name(inode, name); | |
625 | ||
626 | kfree(name); | |
84b3db04 | 627 | if (error) |
1da177e4 LT |
628 | goto out_put; |
629 | ||
630 | HOSTFS_I(inode)->fd = fd; | |
631 | HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; | |
632 | d_instantiate(dentry, inode); | |
f1adc05e | 633 | return 0; |
1da177e4 LT |
634 | |
635 | out_put: | |
636 | iput(inode); | |
637 | out: | |
f1adc05e | 638 | return error; |
1da177e4 LT |
639 | } |
640 | ||
641 | struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, | |
f1adc05e | 642 | struct nameidata *nd) |
1da177e4 LT |
643 | { |
644 | struct inode *inode; | |
645 | char *name; | |
646 | int err; | |
647 | ||
0a370e5d DH |
648 | inode = hostfs_iget(ino->i_sb); |
649 | if (IS_ERR(inode)) { | |
650 | err = PTR_ERR(inode); | |
1da177e4 | 651 | goto out; |
0a370e5d | 652 | } |
1da177e4 LT |
653 | |
654 | err = init_inode(inode, dentry); | |
84b3db04 | 655 | if (err) |
1da177e4 LT |
656 | goto out_put; |
657 | ||
658 | err = -ENOMEM; | |
659 | name = dentry_name(dentry, 0); | |
84b3db04 | 660 | if (name == NULL) |
1da177e4 LT |
661 | goto out_put; |
662 | ||
663 | err = read_name(inode, name); | |
664 | kfree(name); | |
84b3db04 | 665 | if (err == -ENOENT) { |
1da177e4 LT |
666 | iput(inode); |
667 | inode = NULL; | |
668 | } | |
84b3db04 | 669 | else if (err) |
1da177e4 LT |
670 | goto out_put; |
671 | ||
672 | d_add(dentry, inode); | |
673 | dentry->d_op = &hostfs_dentry_ops; | |
f1adc05e | 674 | return NULL; |
1da177e4 LT |
675 | |
676 | out_put: | |
677 | iput(inode); | |
678 | out: | |
f1adc05e | 679 | return ERR_PTR(err); |
1da177e4 LT |
680 | } |
681 | ||
682 | static char *inode_dentry_name(struct inode *ino, struct dentry *dentry) | |
683 | { | |
f1adc05e | 684 | char *file; |
1da177e4 LT |
685 | int len; |
686 | ||
687 | file = inode_name(ino, dentry->d_name.len + 1); | |
84b3db04 | 688 | if (file == NULL) |
f1adc05e JD |
689 | return NULL; |
690 | strcat(file, "/"); | |
1da177e4 | 691 | len = strlen(file); |
f1adc05e | 692 | strncat(file, dentry->d_name.name, dentry->d_name.len); |
1da177e4 | 693 | file[len + dentry->d_name.len] = '\0'; |
f1adc05e | 694 | return file; |
1da177e4 LT |
695 | } |
696 | ||
697 | int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) | |
698 | { | |
f1adc05e JD |
699 | char *from_name, *to_name; |
700 | int err; | |
1da177e4 | 701 | |
84b3db04 | 702 | if ((from_name = inode_dentry_name(ino, from)) == NULL) |
f1adc05e JD |
703 | return -ENOMEM; |
704 | to_name = dentry_name(to, 0); | |
84b3db04 | 705 | if (to_name == NULL) { |
1da177e4 | 706 | kfree(from_name); |
f1adc05e | 707 | return -ENOMEM; |
1da177e4 | 708 | } |
f1adc05e JD |
709 | err = link_file(to_name, from_name); |
710 | kfree(from_name); | |
711 | kfree(to_name); | |
712 | return err; | |
1da177e4 LT |
713 | } |
714 | ||
715 | int hostfs_unlink(struct inode *ino, struct dentry *dentry) | |
716 | { | |
717 | char *file; | |
718 | int err; | |
719 | ||
84b3db04 | 720 | if ((file = inode_dentry_name(ino, dentry)) == NULL) |
f1adc05e | 721 | return -ENOMEM; |
84b3db04 | 722 | if (append) |
f1adc05e | 723 | return -EPERM; |
1da177e4 LT |
724 | |
725 | err = unlink_file(file); | |
726 | kfree(file); | |
f1adc05e | 727 | return err; |
1da177e4 LT |
728 | } |
729 | ||
730 | int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) | |
731 | { | |
732 | char *file; | |
733 | int err; | |
734 | ||
84b3db04 | 735 | if ((file = inode_dentry_name(ino, dentry)) == NULL) |
f1adc05e | 736 | return -ENOMEM; |
1da177e4 LT |
737 | err = make_symlink(file, to); |
738 | kfree(file); | |
f1adc05e | 739 | return err; |
1da177e4 LT |
740 | } |
741 | ||
742 | int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) | |
743 | { | |
744 | char *file; | |
745 | int err; | |
746 | ||
84b3db04 | 747 | if ((file = inode_dentry_name(ino, dentry)) == NULL) |
f1adc05e | 748 | return -ENOMEM; |
1da177e4 LT |
749 | err = do_mkdir(file, mode); |
750 | kfree(file); | |
f1adc05e | 751 | return err; |
1da177e4 LT |
752 | } |
753 | ||
754 | int hostfs_rmdir(struct inode *ino, struct dentry *dentry) | |
755 | { | |
756 | char *file; | |
757 | int err; | |
758 | ||
84b3db04 | 759 | if ((file = inode_dentry_name(ino, dentry)) == NULL) |
f1adc05e | 760 | return -ENOMEM; |
1da177e4 LT |
761 | err = do_rmdir(file); |
762 | kfree(file); | |
f1adc05e | 763 | return err; |
1da177e4 LT |
764 | } |
765 | ||
766 | int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
767 | { | |
768 | struct inode *inode; | |
769 | char *name; | |
0a370e5d | 770 | int err; |
1da177e4 | 771 | |
0a370e5d DH |
772 | inode = hostfs_iget(dir->i_sb); |
773 | if (IS_ERR(inode)) { | |
774 | err = PTR_ERR(inode); | |
1da177e4 | 775 | goto out; |
0a370e5d | 776 | } |
1da177e4 LT |
777 | |
778 | err = init_inode(inode, dentry); | |
84b3db04 | 779 | if (err) |
1da177e4 LT |
780 | goto out_put; |
781 | ||
782 | err = -ENOMEM; | |
783 | name = dentry_name(dentry, 0); | |
84b3db04 | 784 | if (name == NULL) |
1da177e4 LT |
785 | goto out_put; |
786 | ||
787 | init_special_inode(inode, mode, dev); | |
88f6cd0c | 788 | err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); |
84b3db04 | 789 | if (err) |
1da177e4 LT |
790 | goto out_free; |
791 | ||
792 | err = read_name(inode, name); | |
793 | kfree(name); | |
84b3db04 | 794 | if (err) |
1da177e4 LT |
795 | goto out_put; |
796 | ||
797 | d_instantiate(dentry, inode); | |
f1adc05e | 798 | return 0; |
1da177e4 LT |
799 | |
800 | out_free: | |
801 | kfree(name); | |
802 | out_put: | |
803 | iput(inode); | |
804 | out: | |
f1adc05e | 805 | return err; |
1da177e4 LT |
806 | } |
807 | ||
808 | int hostfs_rename(struct inode *from_ino, struct dentry *from, | |
809 | struct inode *to_ino, struct dentry *to) | |
810 | { | |
811 | char *from_name, *to_name; | |
812 | int err; | |
813 | ||
84b3db04 | 814 | if ((from_name = inode_dentry_name(from_ino, from)) == NULL) |
f1adc05e | 815 | return -ENOMEM; |
84b3db04 | 816 | if ((to_name = inode_dentry_name(to_ino, to)) == NULL) { |
1da177e4 | 817 | kfree(from_name); |
f1adc05e | 818 | return -ENOMEM; |
1da177e4 LT |
819 | } |
820 | err = rename_file(from_name, to_name); | |
821 | kfree(from_name); | |
822 | kfree(to_name); | |
f1adc05e | 823 | return err; |
1da177e4 LT |
824 | } |
825 | ||
e6305c43 | 826 | int hostfs_permission(struct inode *ino, int desired) |
1da177e4 LT |
827 | { |
828 | char *name; | |
829 | int r = 0, w = 0, x = 0, err; | |
830 | ||
831 | if (desired & MAY_READ) r = 1; | |
832 | if (desired & MAY_WRITE) w = 1; | |
833 | if (desired & MAY_EXEC) x = 1; | |
834 | name = inode_name(ino, 0); | |
f1adc05e JD |
835 | if (name == NULL) |
836 | return -ENOMEM; | |
1da177e4 LT |
837 | |
838 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || | |
84b3db04 | 839 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) |
1da177e4 LT |
840 | err = 0; |
841 | else | |
842 | err = access_file(name, r, w, x); | |
843 | kfree(name); | |
84b3db04 | 844 | if (!err) |
1da177e4 LT |
845 | err = generic_permission(ino, desired, NULL); |
846 | return err; | |
847 | } | |
848 | ||
849 | int hostfs_setattr(struct dentry *dentry, struct iattr *attr) | |
850 | { | |
851 | struct hostfs_iattr attrs; | |
852 | char *name; | |
853 | int err; | |
854 | ||
5822b7fa AB |
855 | int fd = HOSTFS_I(dentry->d_inode)->fd; |
856 | ||
1da177e4 LT |
857 | err = inode_change_ok(dentry->d_inode, attr); |
858 | if (err) | |
859 | return err; | |
860 | ||
84b3db04 | 861 | if (append) |
1da177e4 LT |
862 | attr->ia_valid &= ~ATTR_SIZE; |
863 | ||
864 | attrs.ia_valid = 0; | |
84b3db04 | 865 | if (attr->ia_valid & ATTR_MODE) { |
1da177e4 LT |
866 | attrs.ia_valid |= HOSTFS_ATTR_MODE; |
867 | attrs.ia_mode = attr->ia_mode; | |
868 | } | |
84b3db04 | 869 | if (attr->ia_valid & ATTR_UID) { |
1da177e4 LT |
870 | attrs.ia_valid |= HOSTFS_ATTR_UID; |
871 | attrs.ia_uid = attr->ia_uid; | |
872 | } | |
84b3db04 | 873 | if (attr->ia_valid & ATTR_GID) { |
1da177e4 LT |
874 | attrs.ia_valid |= HOSTFS_ATTR_GID; |
875 | attrs.ia_gid = attr->ia_gid; | |
876 | } | |
84b3db04 | 877 | if (attr->ia_valid & ATTR_SIZE) { |
1da177e4 LT |
878 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; |
879 | attrs.ia_size = attr->ia_size; | |
880 | } | |
84b3db04 | 881 | if (attr->ia_valid & ATTR_ATIME) { |
1da177e4 LT |
882 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; |
883 | attrs.ia_atime = attr->ia_atime; | |
884 | } | |
84b3db04 | 885 | if (attr->ia_valid & ATTR_MTIME) { |
1da177e4 LT |
886 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; |
887 | attrs.ia_mtime = attr->ia_mtime; | |
888 | } | |
84b3db04 | 889 | if (attr->ia_valid & ATTR_CTIME) { |
1da177e4 LT |
890 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; |
891 | attrs.ia_ctime = attr->ia_ctime; | |
892 | } | |
84b3db04 | 893 | if (attr->ia_valid & ATTR_ATIME_SET) { |
1da177e4 LT |
894 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; |
895 | } | |
84b3db04 | 896 | if (attr->ia_valid & ATTR_MTIME_SET) { |
1da177e4 LT |
897 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; |
898 | } | |
899 | name = dentry_name(dentry, 0); | |
84b3db04 | 900 | if (name == NULL) |
f1adc05e | 901 | return -ENOMEM; |
5822b7fa | 902 | err = set_attr(name, &attrs, fd); |
1da177e4 | 903 | kfree(name); |
84b3db04 | 904 | if (err) |
f1adc05e | 905 | return err; |
1da177e4 | 906 | |
f1adc05e | 907 | return inode_setattr(dentry->d_inode, attr); |
1da177e4 LT |
908 | } |
909 | ||
92e1d5be | 910 | static const struct inode_operations hostfs_iops = { |
1da177e4 LT |
911 | .create = hostfs_create, |
912 | .link = hostfs_link, | |
913 | .unlink = hostfs_unlink, | |
914 | .symlink = hostfs_symlink, | |
915 | .mkdir = hostfs_mkdir, | |
916 | .rmdir = hostfs_rmdir, | |
917 | .mknod = hostfs_mknod, | |
918 | .rename = hostfs_rename, | |
1da177e4 LT |
919 | .permission = hostfs_permission, |
920 | .setattr = hostfs_setattr, | |
1da177e4 LT |
921 | }; |
922 | ||
92e1d5be | 923 | static const struct inode_operations hostfs_dir_iops = { |
1da177e4 LT |
924 | .create = hostfs_create, |
925 | .lookup = hostfs_lookup, | |
926 | .link = hostfs_link, | |
927 | .unlink = hostfs_unlink, | |
928 | .symlink = hostfs_symlink, | |
929 | .mkdir = hostfs_mkdir, | |
930 | .rmdir = hostfs_rmdir, | |
931 | .mknod = hostfs_mknod, | |
932 | .rename = hostfs_rename, | |
1da177e4 LT |
933 | .permission = hostfs_permission, |
934 | .setattr = hostfs_setattr, | |
1da177e4 LT |
935 | }; |
936 | ||
937 | int hostfs_link_readpage(struct file *file, struct page *page) | |
938 | { | |
939 | char *buffer, *name; | |
1da177e4 LT |
940 | int err; |
941 | ||
1da177e4 LT |
942 | buffer = kmap(page); |
943 | name = inode_name(page->mapping->host, 0); | |
84b3db04 | 944 | if (name == NULL) |
f1adc05e | 945 | return -ENOMEM; |
ea7e743e | 946 | err = hostfs_do_readlink(name, buffer, PAGE_CACHE_SIZE); |
1da177e4 | 947 | kfree(name); |
84b3db04 | 948 | if (err == PAGE_CACHE_SIZE) |
1da177e4 | 949 | err = -E2BIG; |
84b3db04 | 950 | else if (err > 0) { |
1da177e4 LT |
951 | flush_dcache_page(page); |
952 | SetPageUptodate(page); | |
953 | if (PageError(page)) ClearPageError(page); | |
954 | err = 0; | |
955 | } | |
956 | kunmap(page); | |
957 | unlock_page(page); | |
f1adc05e | 958 | return err; |
1da177e4 LT |
959 | } |
960 | ||
f5e54d6e | 961 | static const struct address_space_operations hostfs_link_aops = { |
1da177e4 LT |
962 | .readpage = hostfs_link_readpage, |
963 | }; | |
964 | ||
965 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) | |
966 | { | |
967 | struct inode *root_inode; | |
75e8defb | 968 | char *host_root_path, *req_root = d; |
1da177e4 LT |
969 | int err; |
970 | ||
971 | sb->s_blocksize = 1024; | |
972 | sb->s_blocksize_bits = 10; | |
973 | sb->s_magic = HOSTFS_SUPER_MAGIC; | |
974 | sb->s_op = &hostfs_sbops; | |
975 | ||
a6eb0be6 | 976 | /* NULL is printed as <NULL> by sprintf: avoid that. */ |
75e8defb PBG |
977 | if (req_root == NULL) |
978 | req_root = ""; | |
1da177e4 LT |
979 | |
980 | err = -ENOMEM; | |
75e8defb PBG |
981 | host_root_path = kmalloc(strlen(root_ino) + 1 |
982 | + strlen(req_root) + 1, GFP_KERNEL); | |
84b3db04 | 983 | if (host_root_path == NULL) |
1da177e4 LT |
984 | goto out; |
985 | ||
75e8defb | 986 | sprintf(host_root_path, "%s/%s", root_ino, req_root); |
1da177e4 | 987 | |
0a370e5d DH |
988 | root_inode = hostfs_iget(sb); |
989 | if (IS_ERR(root_inode)) { | |
990 | err = PTR_ERR(root_inode); | |
1da177e4 | 991 | goto out_free; |
0a370e5d | 992 | } |
1da177e4 LT |
993 | |
994 | err = init_inode(root_inode, NULL); | |
84b3db04 | 995 | if (err) |
1da177e4 LT |
996 | goto out_put; |
997 | ||
75e8defb | 998 | HOSTFS_I(root_inode)->host_filename = host_root_path; |
84b3db04 JD |
999 | /* |
1000 | * Avoid that in the error path, iput(root_inode) frees again | |
1001 | * host_root_path through hostfs_destroy_inode! | |
1002 | */ | |
75e8defb | 1003 | host_root_path = NULL; |
1da177e4 LT |
1004 | |
1005 | err = -ENOMEM; | |
1006 | sb->s_root = d_alloc_root(root_inode); | |
84b3db04 | 1007 | if (sb->s_root == NULL) |
1da177e4 LT |
1008 | goto out_put; |
1009 | ||
0a370e5d | 1010 | err = hostfs_read_inode(root_inode); |
84b3db04 | 1011 | if (err) { |
f1adc05e JD |
1012 | /* No iput in this case because the dput does that for us */ |
1013 | dput(sb->s_root); | |
1014 | sb->s_root = NULL; | |
bca27113 | 1015 | goto out; |
f1adc05e | 1016 | } |
1da177e4 | 1017 | |
f1adc05e | 1018 | return 0; |
1da177e4 | 1019 | |
f1adc05e JD |
1020 | out_put: |
1021 | iput(root_inode); | |
1022 | out_free: | |
75e8defb | 1023 | kfree(host_root_path); |
f1adc05e JD |
1024 | out: |
1025 | return err; | |
1da177e4 LT |
1026 | } |
1027 | ||
454e2398 DH |
1028 | static int hostfs_read_sb(struct file_system_type *type, |
1029 | int flags, const char *dev_name, | |
1030 | void *data, struct vfsmount *mnt) | |
1da177e4 | 1031 | { |
454e2398 | 1032 | return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt); |
1da177e4 LT |
1033 | } |
1034 | ||
1035 | static struct file_system_type hostfs_type = { | |
1036 | .owner = THIS_MODULE, | |
1037 | .name = "hostfs", | |
1038 | .get_sb = hostfs_read_sb, | |
1039 | .kill_sb = kill_anon_super, | |
1040 | .fs_flags = 0, | |
1041 | }; | |
1042 | ||
1043 | static int __init init_hostfs(void) | |
1044 | { | |
f1adc05e | 1045 | return register_filesystem(&hostfs_type); |
1da177e4 LT |
1046 | } |
1047 | ||
1048 | static void __exit exit_hostfs(void) | |
1049 | { | |
1050 | unregister_filesystem(&hostfs_type); | |
1051 | } | |
1052 | ||
1053 | module_init(init_hostfs) | |
1054 | module_exit(exit_hostfs) | |
1055 | MODULE_LICENSE("GPL"); |