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> |
2b3b9bb0 | 10 | #include <linux/magic.h> |
1da177e4 | 11 | #include <linux/module.h> |
84b3db04 | 12 | #include <linux/mm.h> |
1da177e4 | 13 | #include <linux/pagemap.h> |
1da177e4 | 14 | #include <linux/statfs.h> |
5a0e3ad6 | 15 | #include <linux/slab.h> |
dd2cc4df | 16 | #include <linux/seq_file.h> |
6966a977 | 17 | #include <linux/mount.h> |
d0352d3e | 18 | #include <linux/namei.h> |
1da177e4 | 19 | #include "hostfs.h" |
37185b33 AV |
20 | #include <init.h> |
21 | #include <kern.h> | |
1da177e4 LT |
22 | |
23 | struct hostfs_inode_info { | |
1da177e4 | 24 | int fd; |
aeb5d727 | 25 | fmode_t mode; |
1da177e4 | 26 | struct inode vfs_inode; |
69886e67 | 27 | struct mutex open_mutex; |
1da177e4 LT |
28 | }; |
29 | ||
30 | static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) | |
31 | { | |
f1adc05e | 32 | return list_entry(inode, struct hostfs_inode_info, vfs_inode); |
1da177e4 LT |
33 | } |
34 | ||
496ad9aa | 35 | #define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file)) |
1da177e4 | 36 | |
1da177e4 | 37 | /* Changed in hostfs_args before the kernel starts running */ |
a6eb0be6 | 38 | static char *root_ino = ""; |
1da177e4 LT |
39 | static int append = 0; |
40 | ||
92e1d5be AV |
41 | static const struct inode_operations hostfs_iops; |
42 | static const struct inode_operations hostfs_dir_iops; | |
d0352d3e | 43 | static const struct inode_operations hostfs_link_iops; |
1da177e4 LT |
44 | |
45 | #ifndef MODULE | |
46 | static int __init hostfs_args(char *options, int *add) | |
47 | { | |
48 | char *ptr; | |
49 | ||
50 | ptr = strchr(options, ','); | |
84b3db04 | 51 | if (ptr != NULL) |
1da177e4 | 52 | *ptr++ = '\0'; |
84b3db04 | 53 | if (*options != '\0') |
1da177e4 LT |
54 | root_ino = options; |
55 | ||
56 | options = ptr; | |
84b3db04 | 57 | while (options) { |
1da177e4 | 58 | ptr = strchr(options, ','); |
84b3db04 | 59 | if (ptr != NULL) |
1da177e4 | 60 | *ptr++ = '\0'; |
84b3db04 JD |
61 | if (*options != '\0') { |
62 | if (!strcmp(options, "append")) | |
1da177e4 LT |
63 | append = 1; |
64 | else printf("hostfs_args - unsupported option - %s\n", | |
65 | options); | |
66 | } | |
67 | options = ptr; | |
68 | } | |
f1adc05e | 69 | return 0; |
1da177e4 LT |
70 | } |
71 | ||
72 | __uml_setup("hostfs=", hostfs_args, | |
73 | "hostfs=<root dir>,<flags>,...\n" | |
74 | " This is used to set hostfs parameters. The root directory argument\n" | |
75 | " is used to confine all hostfs mounts to within the specified directory\n" | |
76 | " tree on the host. If this isn't specified, then a user inside UML can\n" | |
77 | " mount anything on the host that's accessible to the user that's running\n" | |
78 | " it.\n" | |
79 | " The only flag currently supported is 'append', which specifies that all\n" | |
80 | " files opened by hostfs will be opened in append mode.\n\n" | |
81 | ); | |
82 | #endif | |
83 | ||
e9193059 | 84 | static char *__dentry_name(struct dentry *dentry, char *name) |
1da177e4 | 85 | { |
ec2447c2 | 86 | char *p = dentry_path_raw(dentry, name, PATH_MAX); |
e9193059 AV |
87 | char *root; |
88 | size_t len; | |
1da177e4 | 89 | |
e9193059 AV |
90 | root = dentry->d_sb->s_fs_info; |
91 | len = strlen(root); | |
92 | if (IS_ERR(p)) { | |
93 | __putname(name); | |
f1adc05e | 94 | return NULL; |
1da177e4 | 95 | } |
aad50b1e RW |
96 | |
97 | /* | |
98 | * This function relies on the fact that dentry_path_raw() will place | |
99 | * the path name at the end of the provided buffer. | |
100 | */ | |
101 | BUG_ON(p + strlen(p) + 1 != name + PATH_MAX); | |
102 | ||
850a496f | 103 | strlcpy(name, root, PATH_MAX); |
e9193059 AV |
104 | if (len > p - name) { |
105 | __putname(name); | |
106 | return NULL; | |
107 | } | |
c278e81b RW |
108 | |
109 | if (p > name + len) | |
110 | strcpy(name + len, p); | |
111 | ||
f1adc05e | 112 | return name; |
1da177e4 LT |
113 | } |
114 | ||
e9193059 AV |
115 | static char *dentry_name(struct dentry *dentry) |
116 | { | |
117 | char *name = __getname(); | |
118 | if (!name) | |
119 | return NULL; | |
120 | ||
9dcc5e8a | 121 | return __dentry_name(dentry, name); |
e9193059 AV |
122 | } |
123 | ||
c5322220 | 124 | static char *inode_name(struct inode *ino) |
1da177e4 LT |
125 | { |
126 | struct dentry *dentry; | |
ec2447c2 | 127 | char *name; |
1da177e4 | 128 | |
ec2447c2 NP |
129 | dentry = d_find_alias(ino); |
130 | if (!dentry) | |
e9193059 | 131 | return NULL; |
ec2447c2 NP |
132 | |
133 | name = dentry_name(dentry); | |
134 | ||
135 | dput(dentry); | |
136 | ||
137 | return name; | |
1da177e4 LT |
138 | } |
139 | ||
1da177e4 LT |
140 | static char *follow_link(char *link) |
141 | { | |
142 | int len, n; | |
143 | char *name, *resolved, *end; | |
144 | ||
7c950992 RW |
145 | name = __getname(); |
146 | if (!name) { | |
1da177e4 | 147 | n = -ENOMEM; |
7c950992 | 148 | goto out_free; |
1da177e4 | 149 | } |
7c950992 RW |
150 | |
151 | n = hostfs_do_readlink(link, name, PATH_MAX); | |
84b3db04 | 152 | if (n < 0) |
1da177e4 | 153 | goto out_free; |
7c950992 RW |
154 | else if (n == PATH_MAX) { |
155 | n = -E2BIG; | |
156 | goto out_free; | |
157 | } | |
1da177e4 | 158 | |
84b3db04 | 159 | if (*name == '/') |
f1adc05e | 160 | return name; |
1da177e4 LT |
161 | |
162 | end = strrchr(link, '/'); | |
84b3db04 | 163 | if (end == NULL) |
f1adc05e | 164 | return name; |
1da177e4 LT |
165 | |
166 | *(end + 1) = '\0'; | |
167 | len = strlen(link) + strlen(name) + 1; | |
168 | ||
169 | resolved = kmalloc(len, GFP_KERNEL); | |
84b3db04 | 170 | if (resolved == NULL) { |
1da177e4 LT |
171 | n = -ENOMEM; |
172 | goto out_free; | |
173 | } | |
174 | ||
175 | sprintf(resolved, "%s%s", link, name); | |
7c950992 | 176 | __putname(name); |
1da177e4 | 177 | kfree(link); |
f1adc05e | 178 | return resolved; |
1da177e4 LT |
179 | |
180 | out_free: | |
7c950992 | 181 | __putname(name); |
f1adc05e | 182 | return ERR_PTR(n); |
1da177e4 LT |
183 | } |
184 | ||
0a370e5d DH |
185 | static struct inode *hostfs_iget(struct super_block *sb) |
186 | { | |
52b209f7 | 187 | struct inode *inode = new_inode(sb); |
0a370e5d DH |
188 | if (!inode) |
189 | return ERR_PTR(-ENOMEM); | |
0a370e5d DH |
190 | return inode; |
191 | } | |
192 | ||
9e443bc3 | 193 | static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) |
1da177e4 | 194 | { |
84b3db04 JD |
195 | /* |
196 | * do_statfs uses struct statfs64 internally, but the linux kernel | |
1da177e4 LT |
197 | * struct statfs still has 32-bit versions for most of these fields, |
198 | * so we convert them here | |
199 | */ | |
200 | int err; | |
201 | long long f_blocks; | |
202 | long long f_bfree; | |
203 | long long f_bavail; | |
204 | long long f_files; | |
205 | long long f_ffree; | |
206 | ||
601d2c38 | 207 | err = do_statfs(dentry->d_sb->s_fs_info, |
1da177e4 LT |
208 | &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, |
209 | &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), | |
1b627d57 | 210 | &sf->f_namelen); |
84b3db04 | 211 | if (err) |
f1adc05e | 212 | return err; |
1da177e4 LT |
213 | sf->f_blocks = f_blocks; |
214 | sf->f_bfree = f_bfree; | |
215 | sf->f_bavail = f_bavail; | |
216 | sf->f_files = f_files; | |
217 | sf->f_ffree = f_ffree; | |
218 | sf->f_type = HOSTFS_SUPER_MAGIC; | |
f1adc05e | 219 | return 0; |
1da177e4 LT |
220 | } |
221 | ||
222 | static struct inode *hostfs_alloc_inode(struct super_block *sb) | |
223 | { | |
224 | struct hostfs_inode_info *hi; | |
225 | ||
371fdab1 | 226 | hi = kmalloc(sizeof(*hi), GFP_KERNEL); |
84b3db04 | 227 | if (hi == NULL) |
f1adc05e | 228 | return NULL; |
601d2c38 | 229 | hi->fd = -1; |
371fdab1 | 230 | hi->mode = 0; |
1da177e4 | 231 | inode_init_once(&hi->vfs_inode); |
69886e67 | 232 | mutex_init(&hi->open_mutex); |
f1adc05e | 233 | return &hi->vfs_inode; |
1da177e4 LT |
234 | } |
235 | ||
e971a6d7 | 236 | static void hostfs_evict_inode(struct inode *inode) |
1da177e4 | 237 | { |
91b0abe3 | 238 | truncate_inode_pages_final(&inode->i_data); |
dbd5768f | 239 | clear_inode(inode); |
84b3db04 | 240 | if (HOSTFS_I(inode)->fd != -1) { |
1da177e4 LT |
241 | close_file(&HOSTFS_I(inode)->fd); |
242 | HOSTFS_I(inode)->fd = -1; | |
243 | } | |
1da177e4 LT |
244 | } |
245 | ||
fa0d7e3d | 246 | static void hostfs_i_callback(struct rcu_head *head) |
1da177e4 | 247 | { |
fa0d7e3d | 248 | struct inode *inode = container_of(head, struct inode, i_rcu); |
1da177e4 LT |
249 | kfree(HOSTFS_I(inode)); |
250 | } | |
fa0d7e3d NP |
251 | |
252 | static void hostfs_destroy_inode(struct inode *inode) | |
253 | { | |
254 | call_rcu(&inode->i_rcu, hostfs_i_callback); | |
255 | } | |
1da177e4 | 256 | |
34c80b1d | 257 | static int hostfs_show_options(struct seq_file *seq, struct dentry *root) |
dd2cc4df | 258 | { |
34c80b1d | 259 | const char *root_path = root->d_sb->s_fs_info; |
dd2cc4df MS |
260 | size_t offset = strlen(root_ino) + 1; |
261 | ||
262 | if (strlen(root_path) > offset) | |
263 | seq_printf(seq, ",%s", root_path + offset); | |
264 | ||
7f74a668 RW |
265 | if (append) |
266 | seq_puts(seq, ",append"); | |
267 | ||
dd2cc4df MS |
268 | return 0; |
269 | } | |
270 | ||
ee9b6d61 | 271 | static const struct super_operations hostfs_sbops = { |
1da177e4 | 272 | .alloc_inode = hostfs_alloc_inode, |
1da177e4 | 273 | .destroy_inode = hostfs_destroy_inode, |
e971a6d7 | 274 | .evict_inode = hostfs_evict_inode, |
1da177e4 | 275 | .statfs = hostfs_statfs, |
dd2cc4df | 276 | .show_options = hostfs_show_options, |
1da177e4 LT |
277 | }; |
278 | ||
9e443bc3 | 279 | static int hostfs_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 LT |
280 | { |
281 | void *dir; | |
282 | char *name; | |
283 | unsigned long long next, ino; | |
284 | int error, len; | |
3ee6bd8e | 285 | unsigned int type; |
1da177e4 | 286 | |
c5322220 | 287 | name = dentry_name(file->f_path.dentry); |
84b3db04 | 288 | if (name == NULL) |
f1adc05e | 289 | return -ENOMEM; |
1da177e4 | 290 | dir = open_dir(name, &error); |
e9193059 | 291 | __putname(name); |
84b3db04 | 292 | if (dir == NULL) |
f1adc05e | 293 | return -error; |
8e28bc7e | 294 | next = ctx->pos; |
3ee6bd8e | 295 | while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) { |
8e28bc7e AV |
296 | if (!dir_emit(ctx, name, len, ino, type)) |
297 | break; | |
298 | ctx->pos = next; | |
1da177e4 LT |
299 | } |
300 | close_dir(dir); | |
f1adc05e | 301 | return 0; |
1da177e4 LT |
302 | } |
303 | ||
4c6dcafc | 304 | static int hostfs_open(struct inode *ino, struct file *file) |
1da177e4 LT |
305 | { |
306 | char *name; | |
bd1052a2 | 307 | fmode_t mode; |
f8ad850f | 308 | int err; |
bd1052a2 | 309 | int r, w, fd; |
1da177e4 LT |
310 | |
311 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); | |
84b3db04 | 312 | if ((mode & HOSTFS_I(ino)->mode) == mode) |
f1adc05e | 313 | return 0; |
1da177e4 | 314 | |
f8ad850f | 315 | mode |= HOSTFS_I(ino)->mode; |
1da177e4 | 316 | |
f8ad850f | 317 | retry: |
a9d1958b RW |
318 | r = w = 0; |
319 | ||
f8ad850f | 320 | if (mode & FMODE_READ) |
1da177e4 | 321 | r = 1; |
f8ad850f | 322 | if (mode & FMODE_WRITE) |
112a5da7 | 323 | r = w = 1; |
1da177e4 | 324 | |
c5322220 | 325 | name = dentry_name(file->f_path.dentry); |
84b3db04 | 326 | if (name == NULL) |
f1adc05e | 327 | return -ENOMEM; |
1da177e4 LT |
328 | |
329 | fd = open_file(name, r, w, append); | |
e9193059 | 330 | __putname(name); |
84b3db04 | 331 | if (fd < 0) |
f1adc05e | 332 | return fd; |
f8ad850f | 333 | |
69886e67 | 334 | mutex_lock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
335 | /* somebody else had handled it first? */ |
336 | if ((mode & HOSTFS_I(ino)->mode) == mode) { | |
69886e67 | 337 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
af955658 | 338 | close_file(&fd); |
f8ad850f AV |
339 | return 0; |
340 | } | |
341 | if ((mode | HOSTFS_I(ino)->mode) != mode) { | |
342 | mode |= HOSTFS_I(ino)->mode; | |
69886e67 | 343 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
344 | close_file(&fd); |
345 | goto retry; | |
346 | } | |
347 | if (HOSTFS_I(ino)->fd == -1) { | |
348 | HOSTFS_I(ino)->fd = fd; | |
349 | } else { | |
350 | err = replace_file(fd, HOSTFS_I(ino)->fd); | |
351 | close_file(&fd); | |
352 | if (err < 0) { | |
69886e67 | 353 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
354 | return err; |
355 | } | |
356 | } | |
357 | HOSTFS_I(ino)->mode = mode; | |
69886e67 | 358 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
1da177e4 | 359 | |
f1adc05e | 360 | return 0; |
1da177e4 LT |
361 | } |
362 | ||
65984ff9 RW |
363 | static int hostfs_file_release(struct inode *inode, struct file *file) |
364 | { | |
365 | filemap_write_and_wait(inode->i_mapping); | |
366 | ||
367 | return 0; | |
368 | } | |
369 | ||
9e443bc3 JH |
370 | static int hostfs_fsync(struct file *file, loff_t start, loff_t end, |
371 | int datasync) | |
1da177e4 | 372 | { |
02c24a82 JB |
373 | struct inode *inode = file->f_mapping->host; |
374 | int ret; | |
375 | ||
376 | ret = filemap_write_and_wait_range(inode->i_mapping, start, end); | |
377 | if (ret) | |
378 | return ret; | |
379 | ||
380 | mutex_lock(&inode->i_mutex); | |
381 | ret = fsync_file(HOSTFS_I(inode)->fd, datasync); | |
382 | mutex_unlock(&inode->i_mutex); | |
383 | ||
384 | return ret; | |
1da177e4 LT |
385 | } |
386 | ||
4b6f5d20 | 387 | static const struct file_operations hostfs_file_fops = { |
1da177e4 | 388 | .llseek = generic_file_llseek, |
aad4f8bb | 389 | .read = new_sync_read, |
5ffc4ef4 | 390 | .splice_read = generic_file_splice_read, |
aad4f8bb | 391 | .read_iter = generic_file_read_iter, |
8174202b AV |
392 | .write_iter = generic_file_write_iter, |
393 | .write = new_sync_write, | |
1da177e4 | 394 | .mmap = generic_file_mmap, |
4c6dcafc | 395 | .open = hostfs_open, |
65984ff9 | 396 | .release = hostfs_file_release, |
1da177e4 LT |
397 | .fsync = hostfs_fsync, |
398 | }; | |
399 | ||
4b6f5d20 | 400 | static const struct file_operations hostfs_dir_fops = { |
1da177e4 | 401 | .llseek = generic_file_llseek, |
8e28bc7e | 402 | .iterate = hostfs_readdir, |
1da177e4 | 403 | .read = generic_read_dir, |
4c6dcafc RW |
404 | .open = hostfs_open, |
405 | .fsync = hostfs_fsync, | |
1da177e4 LT |
406 | }; |
407 | ||
9e443bc3 | 408 | static int hostfs_writepage(struct page *page, struct writeback_control *wbc) |
1da177e4 LT |
409 | { |
410 | struct address_space *mapping = page->mapping; | |
411 | struct inode *inode = mapping->host; | |
412 | char *buffer; | |
413 | unsigned long long base; | |
414 | int count = PAGE_CACHE_SIZE; | |
415 | int end_index = inode->i_size >> PAGE_CACHE_SHIFT; | |
416 | int err; | |
417 | ||
418 | if (page->index >= end_index) | |
419 | count = inode->i_size & (PAGE_CACHE_SIZE-1); | |
420 | ||
421 | buffer = kmap(page); | |
422 | base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; | |
423 | ||
424 | err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); | |
84b3db04 | 425 | if (err != count) { |
1da177e4 LT |
426 | ClearPageUptodate(page); |
427 | goto out; | |
428 | } | |
429 | ||
430 | if (base > inode->i_size) | |
431 | inode->i_size = base; | |
432 | ||
433 | if (PageError(page)) | |
434 | ClearPageError(page); | |
435 | err = 0; | |
436 | ||
437 | out: | |
438 | kunmap(page); | |
439 | ||
440 | unlock_page(page); | |
441 | return err; | |
442 | } | |
443 | ||
9e443bc3 | 444 | static int hostfs_readpage(struct file *file, struct page *page) |
1da177e4 LT |
445 | { |
446 | char *buffer; | |
447 | long long start; | |
b86b413a | 448 | int bytes_read, ret = 0; |
1da177e4 LT |
449 | |
450 | start = (long long) page->index << PAGE_CACHE_SHIFT; | |
451 | buffer = kmap(page); | |
41761ddf | 452 | bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, |
1da177e4 | 453 | PAGE_CACHE_SIZE); |
41761ddf | 454 | if (bytes_read < 0) { |
b86b413a RW |
455 | ClearPageUptodate(page); |
456 | SetPageError(page); | |
41761ddf | 457 | ret = bytes_read; |
84b3db04 | 458 | goto out; |
41761ddf | 459 | } |
1da177e4 | 460 | |
41761ddf | 461 | memset(buffer + bytes_read, 0, PAGE_CACHE_SIZE - bytes_read); |
1da177e4 | 462 | |
b86b413a | 463 | ClearPageError(page); |
1da177e4 | 464 | SetPageUptodate(page); |
b86b413a | 465 | |
1da177e4 | 466 | out: |
b86b413a | 467 | flush_dcache_page(page); |
1da177e4 LT |
468 | kunmap(page); |
469 | unlock_page(page); | |
41761ddf | 470 | return ret; |
1da177e4 LT |
471 | } |
472 | ||
9e443bc3 JH |
473 | static int hostfs_write_begin(struct file *file, struct address_space *mapping, |
474 | loff_t pos, unsigned len, unsigned flags, | |
475 | struct page **pagep, void **fsdata) | |
1da177e4 | 476 | { |
ae361ff4 | 477 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
1da177e4 | 478 | |
54566b2c | 479 | *pagep = grab_cache_page_write_begin(mapping, index, flags); |
ae361ff4 NP |
480 | if (!*pagep) |
481 | return -ENOMEM; | |
482 | return 0; | |
1da177e4 LT |
483 | } |
484 | ||
9e443bc3 JH |
485 | static int hostfs_write_end(struct file *file, struct address_space *mapping, |
486 | loff_t pos, unsigned len, unsigned copied, | |
487 | struct page *page, void *fsdata) | |
1da177e4 | 488 | { |
1da177e4 | 489 | struct inode *inode = mapping->host; |
ae361ff4 NP |
490 | void *buffer; |
491 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
492 | int err; | |
1da177e4 | 493 | |
1da177e4 | 494 | buffer = kmap(page); |
ae361ff4 NP |
495 | err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); |
496 | kunmap(page); | |
30f04a4e | 497 | |
ae361ff4 NP |
498 | if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) |
499 | SetPageUptodate(page); | |
30f04a4e | 500 | |
84b3db04 JD |
501 | /* |
502 | * If err > 0, write_file has added err to pos, so we are comparing | |
ae361ff4 NP |
503 | * i_size against the last byte written. |
504 | */ | |
505 | if (err > 0 && (pos > inode->i_size)) | |
506 | inode->i_size = pos; | |
507 | unlock_page(page); | |
508 | page_cache_release(page); | |
1da177e4 | 509 | |
f1adc05e | 510 | return err; |
1da177e4 LT |
511 | } |
512 | ||
f5e54d6e | 513 | static const struct address_space_operations hostfs_aops = { |
1da177e4 LT |
514 | .writepage = hostfs_writepage, |
515 | .readpage = hostfs_readpage, | |
ffa0aea6 | 516 | .set_page_dirty = __set_page_dirty_nobuffers, |
ae361ff4 NP |
517 | .write_begin = hostfs_write_begin, |
518 | .write_end = hostfs_write_end, | |
1da177e4 LT |
519 | }; |
520 | ||
4754b825 | 521 | static int read_name(struct inode *ino, char *name) |
1da177e4 | 522 | { |
4754b825 AV |
523 | dev_t rdev; |
524 | struct hostfs_stat st; | |
525 | int err = stat_file(name, &st, -1); | |
526 | if (err) | |
527 | return err; | |
1da177e4 | 528 | |
5e2df28c | 529 | /* Reencode maj and min with the kernel encoding.*/ |
4754b825 | 530 | rdev = MKDEV(st.maj, st.min); |
1da177e4 | 531 | |
4754b825 AV |
532 | switch (st.mode & S_IFMT) { |
533 | case S_IFLNK: | |
d0352d3e | 534 | ino->i_op = &hostfs_link_iops; |
1da177e4 | 535 | break; |
4754b825 AV |
536 | case S_IFDIR: |
537 | ino->i_op = &hostfs_dir_iops; | |
538 | ino->i_fop = &hostfs_dir_fops; | |
1da177e4 | 539 | break; |
4754b825 AV |
540 | case S_IFCHR: |
541 | case S_IFBLK: | |
542 | case S_IFIFO: | |
543 | case S_IFSOCK: | |
544 | init_special_inode(ino, st.mode & S_IFMT, rdev); | |
545 | ino->i_op = &hostfs_iops; | |
1da177e4 | 546 | break; |
2ad2dca6 | 547 | case S_IFREG: |
4754b825 AV |
548 | ino->i_op = &hostfs_iops; |
549 | ino->i_fop = &hostfs_file_fops; | |
550 | ino->i_mapping->a_ops = &hostfs_aops; | |
2ad2dca6 RW |
551 | break; |
552 | default: | |
553 | return -EIO; | |
1da177e4 | 554 | } |
4754b825 AV |
555 | |
556 | ino->i_ino = st.ino; | |
557 | ino->i_mode = st.mode; | |
bfe86848 | 558 | set_nlink(ino, st.nlink); |
29f82ae5 EB |
559 | i_uid_write(ino, st.uid); |
560 | i_gid_write(ino, st.gid); | |
4754b825 AV |
561 | ino->i_atime = st.atime; |
562 | ino->i_mtime = st.mtime; | |
563 | ino->i_ctime = st.ctime; | |
564 | ino->i_size = st.size; | |
565 | ino->i_blocks = st.blocks; | |
566 | return 0; | |
1da177e4 LT |
567 | } |
568 | ||
9e443bc3 JH |
569 | static int hostfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
570 | bool excl) | |
1da177e4 LT |
571 | { |
572 | struct inode *inode; | |
573 | char *name; | |
574 | int error, fd; | |
575 | ||
0a370e5d DH |
576 | inode = hostfs_iget(dir->i_sb); |
577 | if (IS_ERR(inode)) { | |
578 | error = PTR_ERR(inode); | |
84b3db04 | 579 | goto out; |
0a370e5d | 580 | } |
1da177e4 | 581 | |
1da177e4 | 582 | error = -ENOMEM; |
c5322220 | 583 | name = dentry_name(dentry); |
84b3db04 | 584 | if (name == NULL) |
1da177e4 LT |
585 | goto out_put; |
586 | ||
587 | fd = file_create(name, | |
588 | mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, | |
589 | mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, | |
590 | mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); | |
4754b825 | 591 | if (fd < 0) |
1da177e4 | 592 | error = fd; |
4754b825 | 593 | else |
5e2df28c | 594 | error = read_name(inode, name); |
1da177e4 | 595 | |
e9193059 | 596 | __putname(name); |
84b3db04 | 597 | if (error) |
1da177e4 LT |
598 | goto out_put; |
599 | ||
600 | HOSTFS_I(inode)->fd = fd; | |
601 | HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; | |
602 | d_instantiate(dentry, inode); | |
f1adc05e | 603 | return 0; |
1da177e4 LT |
604 | |
605 | out_put: | |
606 | iput(inode); | |
607 | out: | |
f1adc05e | 608 | return error; |
1da177e4 LT |
609 | } |
610 | ||
9e443bc3 JH |
611 | static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, |
612 | unsigned int flags) | |
1da177e4 LT |
613 | { |
614 | struct inode *inode; | |
615 | char *name; | |
616 | int err; | |
617 | ||
0a370e5d DH |
618 | inode = hostfs_iget(ino->i_sb); |
619 | if (IS_ERR(inode)) { | |
620 | err = PTR_ERR(inode); | |
1da177e4 | 621 | goto out; |
0a370e5d | 622 | } |
1da177e4 | 623 | |
1da177e4 | 624 | err = -ENOMEM; |
c5322220 | 625 | name = dentry_name(dentry); |
84b3db04 | 626 | if (name == NULL) |
1da177e4 LT |
627 | goto out_put; |
628 | ||
629 | err = read_name(inode, name); | |
5e2df28c | 630 | |
e9193059 | 631 | __putname(name); |
84b3db04 | 632 | if (err == -ENOENT) { |
1da177e4 LT |
633 | iput(inode); |
634 | inode = NULL; | |
635 | } | |
84b3db04 | 636 | else if (err) |
1da177e4 LT |
637 | goto out_put; |
638 | ||
639 | d_add(dentry, inode); | |
f1adc05e | 640 | return NULL; |
1da177e4 LT |
641 | |
642 | out_put: | |
643 | iput(inode); | |
644 | out: | |
f1adc05e | 645 | return ERR_PTR(err); |
1da177e4 LT |
646 | } |
647 | ||
9e443bc3 JH |
648 | static int hostfs_link(struct dentry *to, struct inode *ino, |
649 | struct dentry *from) | |
1da177e4 | 650 | { |
f1adc05e JD |
651 | char *from_name, *to_name; |
652 | int err; | |
1da177e4 | 653 | |
c5322220 | 654 | if ((from_name = dentry_name(from)) == NULL) |
f1adc05e | 655 | return -ENOMEM; |
c5322220 | 656 | to_name = dentry_name(to); |
84b3db04 | 657 | if (to_name == NULL) { |
e9193059 | 658 | __putname(from_name); |
f1adc05e | 659 | return -ENOMEM; |
1da177e4 | 660 | } |
f1adc05e | 661 | err = link_file(to_name, from_name); |
e9193059 AV |
662 | __putname(from_name); |
663 | __putname(to_name); | |
f1adc05e | 664 | return err; |
1da177e4 LT |
665 | } |
666 | ||
9e443bc3 | 667 | static int hostfs_unlink(struct inode *ino, struct dentry *dentry) |
1da177e4 LT |
668 | { |
669 | char *file; | |
670 | int err; | |
671 | ||
84b3db04 | 672 | if (append) |
f1adc05e | 673 | return -EPERM; |
1da177e4 | 674 | |
f8d7e187 AV |
675 | if ((file = dentry_name(dentry)) == NULL) |
676 | return -ENOMEM; | |
677 | ||
1da177e4 | 678 | err = unlink_file(file); |
e9193059 | 679 | __putname(file); |
f1adc05e | 680 | return err; |
1da177e4 LT |
681 | } |
682 | ||
9e443bc3 JH |
683 | static int hostfs_symlink(struct inode *ino, struct dentry *dentry, |
684 | const char *to) | |
1da177e4 LT |
685 | { |
686 | char *file; | |
687 | int err; | |
688 | ||
c5322220 | 689 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 690 | return -ENOMEM; |
1da177e4 | 691 | err = make_symlink(file, to); |
e9193059 | 692 | __putname(file); |
f1adc05e | 693 | return err; |
1da177e4 LT |
694 | } |
695 | ||
9e443bc3 | 696 | static int hostfs_mkdir(struct inode *ino, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
697 | { |
698 | char *file; | |
699 | int err; | |
700 | ||
c5322220 | 701 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 702 | return -ENOMEM; |
1da177e4 | 703 | err = do_mkdir(file, mode); |
e9193059 | 704 | __putname(file); |
f1adc05e | 705 | return err; |
1da177e4 LT |
706 | } |
707 | ||
9e443bc3 | 708 | static int hostfs_rmdir(struct inode *ino, struct dentry *dentry) |
1da177e4 LT |
709 | { |
710 | char *file; | |
711 | int err; | |
712 | ||
c5322220 | 713 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 714 | return -ENOMEM; |
1da177e4 | 715 | err = do_rmdir(file); |
e9193059 | 716 | __putname(file); |
f1adc05e | 717 | return err; |
1da177e4 LT |
718 | } |
719 | ||
1a67aafb | 720 | static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
1da177e4 LT |
721 | { |
722 | struct inode *inode; | |
723 | char *name; | |
0a370e5d | 724 | int err; |
1da177e4 | 725 | |
0a370e5d DH |
726 | inode = hostfs_iget(dir->i_sb); |
727 | if (IS_ERR(inode)) { | |
728 | err = PTR_ERR(inode); | |
1da177e4 | 729 | goto out; |
0a370e5d | 730 | } |
1da177e4 | 731 | |
1da177e4 | 732 | err = -ENOMEM; |
c5322220 | 733 | name = dentry_name(dentry); |
84b3db04 | 734 | if (name == NULL) |
1da177e4 LT |
735 | goto out_put; |
736 | ||
737 | init_special_inode(inode, mode, dev); | |
88f6cd0c | 738 | err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); |
e9193059 | 739 | if (!err) |
1da177e4 LT |
740 | goto out_free; |
741 | ||
742 | err = read_name(inode, name); | |
e9193059 | 743 | __putname(name); |
5e2df28c AV |
744 | if (err) |
745 | goto out_put; | |
84b3db04 | 746 | if (err) |
1da177e4 LT |
747 | goto out_put; |
748 | ||
749 | d_instantiate(dentry, inode); | |
f1adc05e | 750 | return 0; |
1da177e4 LT |
751 | |
752 | out_free: | |
e9193059 | 753 | __putname(name); |
1da177e4 LT |
754 | out_put: |
755 | iput(inode); | |
756 | out: | |
f1adc05e | 757 | return err; |
1da177e4 LT |
758 | } |
759 | ||
9a423bb6 MS |
760 | static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry, |
761 | struct inode *new_dir, struct dentry *new_dentry, | |
762 | unsigned int flags) | |
1da177e4 | 763 | { |
9a423bb6 | 764 | char *old_name, *new_name; |
1da177e4 LT |
765 | int err; |
766 | ||
9a423bb6 MS |
767 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) |
768 | return -EINVAL; | |
769 | ||
770 | old_name = dentry_name(old_dentry); | |
771 | if (old_name == NULL) | |
f1adc05e | 772 | return -ENOMEM; |
9a423bb6 MS |
773 | new_name = dentry_name(new_dentry); |
774 | if (new_name == NULL) { | |
775 | __putname(old_name); | |
f1adc05e | 776 | return -ENOMEM; |
1da177e4 | 777 | } |
9a423bb6 MS |
778 | if (!flags) |
779 | err = rename_file(old_name, new_name); | |
780 | else | |
781 | err = rename2_file(old_name, new_name, flags); | |
782 | ||
783 | __putname(old_name); | |
784 | __putname(new_name); | |
f1adc05e | 785 | return err; |
1da177e4 LT |
786 | } |
787 | ||
9e443bc3 | 788 | static int hostfs_permission(struct inode *ino, int desired) |
1da177e4 LT |
789 | { |
790 | char *name; | |
791 | int r = 0, w = 0, x = 0, err; | |
792 | ||
10556cb2 | 793 | if (desired & MAY_NOT_BLOCK) |
b74c79e9 NP |
794 | return -ECHILD; |
795 | ||
1da177e4 LT |
796 | if (desired & MAY_READ) r = 1; |
797 | if (desired & MAY_WRITE) w = 1; | |
798 | if (desired & MAY_EXEC) x = 1; | |
c5322220 | 799 | name = inode_name(ino); |
f1adc05e JD |
800 | if (name == NULL) |
801 | return -ENOMEM; | |
1da177e4 LT |
802 | |
803 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || | |
84b3db04 | 804 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) |
1da177e4 LT |
805 | err = 0; |
806 | else | |
807 | err = access_file(name, r, w, x); | |
e9193059 | 808 | __putname(name); |
84b3db04 | 809 | if (!err) |
2830ba7f | 810 | err = generic_permission(ino, desired); |
1da177e4 LT |
811 | return err; |
812 | } | |
813 | ||
9e443bc3 | 814 | static int hostfs_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 | 815 | { |
1025774c | 816 | struct inode *inode = dentry->d_inode; |
1da177e4 LT |
817 | struct hostfs_iattr attrs; |
818 | char *name; | |
819 | int err; | |
820 | ||
1025774c | 821 | int fd = HOSTFS_I(inode)->fd; |
5822b7fa | 822 | |
1025774c | 823 | err = inode_change_ok(inode, attr); |
1da177e4 LT |
824 | if (err) |
825 | return err; | |
826 | ||
84b3db04 | 827 | if (append) |
1da177e4 LT |
828 | attr->ia_valid &= ~ATTR_SIZE; |
829 | ||
830 | attrs.ia_valid = 0; | |
84b3db04 | 831 | if (attr->ia_valid & ATTR_MODE) { |
1da177e4 LT |
832 | attrs.ia_valid |= HOSTFS_ATTR_MODE; |
833 | attrs.ia_mode = attr->ia_mode; | |
834 | } | |
84b3db04 | 835 | if (attr->ia_valid & ATTR_UID) { |
1da177e4 | 836 | attrs.ia_valid |= HOSTFS_ATTR_UID; |
29f82ae5 | 837 | attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid); |
1da177e4 | 838 | } |
84b3db04 | 839 | if (attr->ia_valid & ATTR_GID) { |
1da177e4 | 840 | attrs.ia_valid |= HOSTFS_ATTR_GID; |
29f82ae5 | 841 | attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid); |
1da177e4 | 842 | } |
84b3db04 | 843 | if (attr->ia_valid & ATTR_SIZE) { |
1da177e4 LT |
844 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; |
845 | attrs.ia_size = attr->ia_size; | |
846 | } | |
84b3db04 | 847 | if (attr->ia_valid & ATTR_ATIME) { |
1da177e4 LT |
848 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; |
849 | attrs.ia_atime = attr->ia_atime; | |
850 | } | |
84b3db04 | 851 | if (attr->ia_valid & ATTR_MTIME) { |
1da177e4 LT |
852 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; |
853 | attrs.ia_mtime = attr->ia_mtime; | |
854 | } | |
84b3db04 | 855 | if (attr->ia_valid & ATTR_CTIME) { |
1da177e4 LT |
856 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; |
857 | attrs.ia_ctime = attr->ia_ctime; | |
858 | } | |
84b3db04 | 859 | if (attr->ia_valid & ATTR_ATIME_SET) { |
1da177e4 LT |
860 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; |
861 | } | |
84b3db04 | 862 | if (attr->ia_valid & ATTR_MTIME_SET) { |
1da177e4 LT |
863 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; |
864 | } | |
c5322220 | 865 | name = dentry_name(dentry); |
84b3db04 | 866 | if (name == NULL) |
f1adc05e | 867 | return -ENOMEM; |
5822b7fa | 868 | err = set_attr(name, &attrs, fd); |
e9193059 | 869 | __putname(name); |
84b3db04 | 870 | if (err) |
f1adc05e | 871 | return err; |
1da177e4 | 872 | |
1025774c | 873 | if ((attr->ia_valid & ATTR_SIZE) && |
bc077320 | 874 | attr->ia_size != i_size_read(inode)) |
3be2be0a | 875 | truncate_setsize(inode, attr->ia_size); |
1025774c CH |
876 | |
877 | setattr_copy(inode, attr); | |
878 | mark_inode_dirty(inode); | |
879 | return 0; | |
1da177e4 LT |
880 | } |
881 | ||
92e1d5be | 882 | static const struct inode_operations hostfs_iops = { |
1da177e4 LT |
883 | .permission = hostfs_permission, |
884 | .setattr = hostfs_setattr, | |
1da177e4 LT |
885 | }; |
886 | ||
92e1d5be | 887 | static const struct inode_operations hostfs_dir_iops = { |
1da177e4 LT |
888 | .create = hostfs_create, |
889 | .lookup = hostfs_lookup, | |
890 | .link = hostfs_link, | |
891 | .unlink = hostfs_unlink, | |
892 | .symlink = hostfs_symlink, | |
893 | .mkdir = hostfs_mkdir, | |
894 | .rmdir = hostfs_rmdir, | |
895 | .mknod = hostfs_mknod, | |
9a423bb6 | 896 | .rename2 = hostfs_rename2, |
1da177e4 LT |
897 | .permission = hostfs_permission, |
898 | .setattr = hostfs_setattr, | |
1da177e4 LT |
899 | }; |
900 | ||
d0352d3e AV |
901 | static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd) |
902 | { | |
903 | char *link = __getname(); | |
904 | if (link) { | |
905 | char *path = dentry_name(dentry); | |
906 | int err = -ENOMEM; | |
907 | if (path) { | |
3b6036d1 | 908 | err = hostfs_do_readlink(path, link, PATH_MAX); |
d0352d3e AV |
909 | if (err == PATH_MAX) |
910 | err = -E2BIG; | |
e9193059 | 911 | __putname(path); |
d0352d3e AV |
912 | } |
913 | if (err < 0) { | |
914 | __putname(link); | |
915 | link = ERR_PTR(err); | |
916 | } | |
917 | } else { | |
918 | link = ERR_PTR(-ENOMEM); | |
1da177e4 | 919 | } |
d0352d3e AV |
920 | |
921 | nd_set_link(nd, link); | |
922 | return NULL; | |
923 | } | |
924 | ||
925 | static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) | |
926 | { | |
927 | char *s = nd_get_link(nd); | |
928 | if (!IS_ERR(s)) | |
929 | __putname(s); | |
1da177e4 LT |
930 | } |
931 | ||
d0352d3e AV |
932 | static const struct inode_operations hostfs_link_iops = { |
933 | .readlink = generic_readlink, | |
934 | .follow_link = hostfs_follow_link, | |
935 | .put_link = hostfs_put_link, | |
1da177e4 LT |
936 | }; |
937 | ||
938 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) | |
939 | { | |
940 | struct inode *root_inode; | |
75e8defb | 941 | char *host_root_path, *req_root = d; |
1da177e4 LT |
942 | int err; |
943 | ||
944 | sb->s_blocksize = 1024; | |
945 | sb->s_blocksize_bits = 10; | |
946 | sb->s_magic = HOSTFS_SUPER_MAGIC; | |
947 | sb->s_op = &hostfs_sbops; | |
b26d4cd3 | 948 | sb->s_d_op = &simple_dentry_operations; |
752fa51e | 949 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 | 950 | |
a6eb0be6 | 951 | /* NULL is printed as <NULL> by sprintf: avoid that. */ |
75e8defb PBG |
952 | if (req_root == NULL) |
953 | req_root = ""; | |
1da177e4 LT |
954 | |
955 | err = -ENOMEM; | |
601d2c38 AV |
956 | sb->s_fs_info = host_root_path = |
957 | kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); | |
84b3db04 | 958 | if (host_root_path == NULL) |
1da177e4 LT |
959 | goto out; |
960 | ||
75e8defb | 961 | sprintf(host_root_path, "%s/%s", root_ino, req_root); |
1da177e4 | 962 | |
52b209f7 AV |
963 | root_inode = new_inode(sb); |
964 | if (!root_inode) | |
601d2c38 | 965 | goto out; |
1da177e4 | 966 | |
4754b825 AV |
967 | err = read_name(root_inode, host_root_path); |
968 | if (err) | |
969 | goto out_put; | |
52b209f7 | 970 | |
4754b825 | 971 | if (S_ISLNK(root_inode->i_mode)) { |
52b209f7 AV |
972 | char *name = follow_link(host_root_path); |
973 | if (IS_ERR(name)) | |
974 | err = PTR_ERR(name); | |
975 | else | |
976 | err = read_name(root_inode, name); | |
977 | kfree(name); | |
4754b825 AV |
978 | if (err) |
979 | goto out_put; | |
52b209f7 | 980 | } |
1da177e4 | 981 | |
1da177e4 | 982 | err = -ENOMEM; |
48fde701 | 983 | sb->s_root = d_make_root(root_inode); |
84b3db04 | 984 | if (sb->s_root == NULL) |
48fde701 | 985 | goto out; |
1da177e4 | 986 | |
f1adc05e | 987 | return 0; |
1da177e4 | 988 | |
f1adc05e JD |
989 | out_put: |
990 | iput(root_inode); | |
f1adc05e JD |
991 | out: |
992 | return err; | |
1da177e4 LT |
993 | } |
994 | ||
3c26ff6e | 995 | static struct dentry *hostfs_read_sb(struct file_system_type *type, |
454e2398 | 996 | int flags, const char *dev_name, |
3c26ff6e | 997 | void *data) |
1da177e4 | 998 | { |
3c26ff6e | 999 | return mount_nodev(type, flags, data, hostfs_fill_sb_common); |
1da177e4 LT |
1000 | } |
1001 | ||
601d2c38 AV |
1002 | static void hostfs_kill_sb(struct super_block *s) |
1003 | { | |
1004 | kill_anon_super(s); | |
1005 | kfree(s->s_fs_info); | |
1006 | } | |
1007 | ||
1da177e4 LT |
1008 | static struct file_system_type hostfs_type = { |
1009 | .owner = THIS_MODULE, | |
1010 | .name = "hostfs", | |
3c26ff6e | 1011 | .mount = hostfs_read_sb, |
601d2c38 | 1012 | .kill_sb = hostfs_kill_sb, |
1da177e4 LT |
1013 | .fs_flags = 0, |
1014 | }; | |
3e64fe5b | 1015 | MODULE_ALIAS_FS("hostfs"); |
1da177e4 LT |
1016 | |
1017 | static int __init init_hostfs(void) | |
1018 | { | |
f1adc05e | 1019 | return register_filesystem(&hostfs_type); |
1da177e4 LT |
1020 | } |
1021 | ||
1022 | static void __exit exit_hostfs(void) | |
1023 | { | |
1024 | unregister_filesystem(&hostfs_type); | |
1025 | } | |
1026 | ||
1027 | module_init(init_hostfs) | |
1028 | module_exit(exit_hostfs) | |
1029 | MODULE_LICENSE("GPL"); |