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; |
0c9bd636 | 295 | seek_dir(dir, next); |
3ee6bd8e | 296 | while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) { |
8e28bc7e AV |
297 | if (!dir_emit(ctx, name, len, ino, type)) |
298 | break; | |
299 | ctx->pos = next; | |
1da177e4 LT |
300 | } |
301 | close_dir(dir); | |
f1adc05e | 302 | return 0; |
1da177e4 LT |
303 | } |
304 | ||
4c6dcafc | 305 | static int hostfs_open(struct inode *ino, struct file *file) |
1da177e4 LT |
306 | { |
307 | char *name; | |
bd1052a2 | 308 | fmode_t mode; |
f8ad850f | 309 | int err; |
bd1052a2 | 310 | int r, w, fd; |
1da177e4 LT |
311 | |
312 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); | |
84b3db04 | 313 | if ((mode & HOSTFS_I(ino)->mode) == mode) |
f1adc05e | 314 | return 0; |
1da177e4 | 315 | |
f8ad850f | 316 | mode |= HOSTFS_I(ino)->mode; |
1da177e4 | 317 | |
f8ad850f | 318 | retry: |
a9d1958b RW |
319 | r = w = 0; |
320 | ||
f8ad850f | 321 | if (mode & FMODE_READ) |
1da177e4 | 322 | r = 1; |
f8ad850f | 323 | if (mode & FMODE_WRITE) |
112a5da7 | 324 | r = w = 1; |
1da177e4 | 325 | |
c5322220 | 326 | name = dentry_name(file->f_path.dentry); |
84b3db04 | 327 | if (name == NULL) |
f1adc05e | 328 | return -ENOMEM; |
1da177e4 LT |
329 | |
330 | fd = open_file(name, r, w, append); | |
e9193059 | 331 | __putname(name); |
84b3db04 | 332 | if (fd < 0) |
f1adc05e | 333 | return fd; |
f8ad850f | 334 | |
69886e67 | 335 | mutex_lock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
336 | /* somebody else had handled it first? */ |
337 | if ((mode & HOSTFS_I(ino)->mode) == mode) { | |
69886e67 | 338 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
af955658 | 339 | close_file(&fd); |
f8ad850f AV |
340 | return 0; |
341 | } | |
342 | if ((mode | HOSTFS_I(ino)->mode) != mode) { | |
343 | mode |= HOSTFS_I(ino)->mode; | |
69886e67 | 344 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
345 | close_file(&fd); |
346 | goto retry; | |
347 | } | |
348 | if (HOSTFS_I(ino)->fd == -1) { | |
349 | HOSTFS_I(ino)->fd = fd; | |
350 | } else { | |
351 | err = replace_file(fd, HOSTFS_I(ino)->fd); | |
352 | close_file(&fd); | |
353 | if (err < 0) { | |
69886e67 | 354 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
355 | return err; |
356 | } | |
357 | } | |
358 | HOSTFS_I(ino)->mode = mode; | |
69886e67 | 359 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
1da177e4 | 360 | |
f1adc05e | 361 | return 0; |
1da177e4 LT |
362 | } |
363 | ||
65984ff9 RW |
364 | static int hostfs_file_release(struct inode *inode, struct file *file) |
365 | { | |
366 | filemap_write_and_wait(inode->i_mapping); | |
367 | ||
368 | return 0; | |
369 | } | |
370 | ||
9e443bc3 JH |
371 | static int hostfs_fsync(struct file *file, loff_t start, loff_t end, |
372 | int datasync) | |
1da177e4 | 373 | { |
02c24a82 JB |
374 | struct inode *inode = file->f_mapping->host; |
375 | int ret; | |
376 | ||
377 | ret = filemap_write_and_wait_range(inode->i_mapping, start, end); | |
378 | if (ret) | |
379 | return ret; | |
380 | ||
381 | mutex_lock(&inode->i_mutex); | |
382 | ret = fsync_file(HOSTFS_I(inode)->fd, datasync); | |
383 | mutex_unlock(&inode->i_mutex); | |
384 | ||
385 | return ret; | |
1da177e4 LT |
386 | } |
387 | ||
4b6f5d20 | 388 | static const struct file_operations hostfs_file_fops = { |
1da177e4 | 389 | .llseek = generic_file_llseek, |
5ffc4ef4 | 390 | .splice_read = generic_file_splice_read, |
aad4f8bb | 391 | .read_iter = generic_file_read_iter, |
8174202b | 392 | .write_iter = generic_file_write_iter, |
1da177e4 | 393 | .mmap = generic_file_mmap, |
4c6dcafc | 394 | .open = hostfs_open, |
65984ff9 | 395 | .release = hostfs_file_release, |
1da177e4 LT |
396 | .fsync = hostfs_fsync, |
397 | }; | |
398 | ||
4b6f5d20 | 399 | static const struct file_operations hostfs_dir_fops = { |
1da177e4 | 400 | .llseek = generic_file_llseek, |
8e28bc7e | 401 | .iterate = hostfs_readdir, |
1da177e4 | 402 | .read = generic_read_dir, |
4c6dcafc RW |
403 | .open = hostfs_open, |
404 | .fsync = hostfs_fsync, | |
1da177e4 LT |
405 | }; |
406 | ||
9e443bc3 | 407 | static int hostfs_writepage(struct page *page, struct writeback_control *wbc) |
1da177e4 LT |
408 | { |
409 | struct address_space *mapping = page->mapping; | |
410 | struct inode *inode = mapping->host; | |
411 | char *buffer; | |
af6aa1b9 | 412 | loff_t base = page_offset(page); |
1da177e4 LT |
413 | int count = PAGE_CACHE_SIZE; |
414 | int end_index = inode->i_size >> PAGE_CACHE_SHIFT; | |
415 | int err; | |
416 | ||
417 | if (page->index >= end_index) | |
418 | count = inode->i_size & (PAGE_CACHE_SIZE-1); | |
419 | ||
420 | buffer = kmap(page); | |
1da177e4 LT |
421 | |
422 | err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); | |
84b3db04 | 423 | if (err != count) { |
1da177e4 LT |
424 | ClearPageUptodate(page); |
425 | goto out; | |
426 | } | |
427 | ||
428 | if (base > inode->i_size) | |
429 | inode->i_size = base; | |
430 | ||
431 | if (PageError(page)) | |
432 | ClearPageError(page); | |
433 | err = 0; | |
434 | ||
435 | out: | |
436 | kunmap(page); | |
437 | ||
438 | unlock_page(page); | |
439 | return err; | |
440 | } | |
441 | ||
9e443bc3 | 442 | static int hostfs_readpage(struct file *file, struct page *page) |
1da177e4 LT |
443 | { |
444 | char *buffer; | |
af6aa1b9 | 445 | loff_t start = page_offset(page); |
b86b413a | 446 | int bytes_read, ret = 0; |
1da177e4 | 447 | |
1da177e4 | 448 | buffer = kmap(page); |
41761ddf | 449 | bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, |
1da177e4 | 450 | PAGE_CACHE_SIZE); |
41761ddf | 451 | if (bytes_read < 0) { |
b86b413a RW |
452 | ClearPageUptodate(page); |
453 | SetPageError(page); | |
41761ddf | 454 | ret = bytes_read; |
84b3db04 | 455 | goto out; |
41761ddf | 456 | } |
1da177e4 | 457 | |
41761ddf | 458 | memset(buffer + bytes_read, 0, PAGE_CACHE_SIZE - bytes_read); |
1da177e4 | 459 | |
b86b413a | 460 | ClearPageError(page); |
1da177e4 | 461 | SetPageUptodate(page); |
b86b413a | 462 | |
1da177e4 | 463 | out: |
b86b413a | 464 | flush_dcache_page(page); |
1da177e4 LT |
465 | kunmap(page); |
466 | unlock_page(page); | |
41761ddf | 467 | return ret; |
1da177e4 LT |
468 | } |
469 | ||
9e443bc3 JH |
470 | static int hostfs_write_begin(struct file *file, struct address_space *mapping, |
471 | loff_t pos, unsigned len, unsigned flags, | |
472 | struct page **pagep, void **fsdata) | |
1da177e4 | 473 | { |
ae361ff4 | 474 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
1da177e4 | 475 | |
54566b2c | 476 | *pagep = grab_cache_page_write_begin(mapping, index, flags); |
ae361ff4 NP |
477 | if (!*pagep) |
478 | return -ENOMEM; | |
479 | return 0; | |
1da177e4 LT |
480 | } |
481 | ||
9e443bc3 JH |
482 | static int hostfs_write_end(struct file *file, struct address_space *mapping, |
483 | loff_t pos, unsigned len, unsigned copied, | |
484 | struct page *page, void *fsdata) | |
1da177e4 | 485 | { |
1da177e4 | 486 | struct inode *inode = mapping->host; |
ae361ff4 NP |
487 | void *buffer; |
488 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
489 | int err; | |
1da177e4 | 490 | |
1da177e4 | 491 | buffer = kmap(page); |
ae361ff4 NP |
492 | err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); |
493 | kunmap(page); | |
30f04a4e | 494 | |
ae361ff4 NP |
495 | if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) |
496 | SetPageUptodate(page); | |
30f04a4e | 497 | |
84b3db04 JD |
498 | /* |
499 | * If err > 0, write_file has added err to pos, so we are comparing | |
ae361ff4 NP |
500 | * i_size against the last byte written. |
501 | */ | |
502 | if (err > 0 && (pos > inode->i_size)) | |
503 | inode->i_size = pos; | |
504 | unlock_page(page); | |
505 | page_cache_release(page); | |
1da177e4 | 506 | |
f1adc05e | 507 | return err; |
1da177e4 LT |
508 | } |
509 | ||
f5e54d6e | 510 | static const struct address_space_operations hostfs_aops = { |
1da177e4 LT |
511 | .writepage = hostfs_writepage, |
512 | .readpage = hostfs_readpage, | |
ffa0aea6 | 513 | .set_page_dirty = __set_page_dirty_nobuffers, |
ae361ff4 NP |
514 | .write_begin = hostfs_write_begin, |
515 | .write_end = hostfs_write_end, | |
1da177e4 LT |
516 | }; |
517 | ||
4754b825 | 518 | static int read_name(struct inode *ino, char *name) |
1da177e4 | 519 | { |
4754b825 AV |
520 | dev_t rdev; |
521 | struct hostfs_stat st; | |
522 | int err = stat_file(name, &st, -1); | |
523 | if (err) | |
524 | return err; | |
1da177e4 | 525 | |
5e2df28c | 526 | /* Reencode maj and min with the kernel encoding.*/ |
4754b825 | 527 | rdev = MKDEV(st.maj, st.min); |
1da177e4 | 528 | |
4754b825 AV |
529 | switch (st.mode & S_IFMT) { |
530 | case S_IFLNK: | |
d0352d3e | 531 | ino->i_op = &hostfs_link_iops; |
1da177e4 | 532 | break; |
4754b825 AV |
533 | case S_IFDIR: |
534 | ino->i_op = &hostfs_dir_iops; | |
535 | ino->i_fop = &hostfs_dir_fops; | |
1da177e4 | 536 | break; |
4754b825 AV |
537 | case S_IFCHR: |
538 | case S_IFBLK: | |
539 | case S_IFIFO: | |
540 | case S_IFSOCK: | |
541 | init_special_inode(ino, st.mode & S_IFMT, rdev); | |
542 | ino->i_op = &hostfs_iops; | |
1da177e4 | 543 | break; |
2ad2dca6 | 544 | case S_IFREG: |
4754b825 AV |
545 | ino->i_op = &hostfs_iops; |
546 | ino->i_fop = &hostfs_file_fops; | |
547 | ino->i_mapping->a_ops = &hostfs_aops; | |
2ad2dca6 RW |
548 | break; |
549 | default: | |
550 | return -EIO; | |
1da177e4 | 551 | } |
4754b825 AV |
552 | |
553 | ino->i_ino = st.ino; | |
554 | ino->i_mode = st.mode; | |
bfe86848 | 555 | set_nlink(ino, st.nlink); |
29f82ae5 EB |
556 | i_uid_write(ino, st.uid); |
557 | i_gid_write(ino, st.gid); | |
4754b825 AV |
558 | ino->i_atime = st.atime; |
559 | ino->i_mtime = st.mtime; | |
560 | ino->i_ctime = st.ctime; | |
561 | ino->i_size = st.size; | |
562 | ino->i_blocks = st.blocks; | |
563 | return 0; | |
1da177e4 LT |
564 | } |
565 | ||
9e443bc3 JH |
566 | static int hostfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
567 | bool excl) | |
1da177e4 LT |
568 | { |
569 | struct inode *inode; | |
570 | char *name; | |
571 | int error, fd; | |
572 | ||
0a370e5d DH |
573 | inode = hostfs_iget(dir->i_sb); |
574 | if (IS_ERR(inode)) { | |
575 | error = PTR_ERR(inode); | |
84b3db04 | 576 | goto out; |
0a370e5d | 577 | } |
1da177e4 | 578 | |
1da177e4 | 579 | error = -ENOMEM; |
c5322220 | 580 | name = dentry_name(dentry); |
84b3db04 | 581 | if (name == NULL) |
1da177e4 LT |
582 | goto out_put; |
583 | ||
a718c922 | 584 | fd = file_create(name, mode & 0777); |
4754b825 | 585 | if (fd < 0) |
1da177e4 | 586 | error = fd; |
4754b825 | 587 | else |
5e2df28c | 588 | error = read_name(inode, name); |
1da177e4 | 589 | |
e9193059 | 590 | __putname(name); |
84b3db04 | 591 | if (error) |
1da177e4 LT |
592 | goto out_put; |
593 | ||
594 | HOSTFS_I(inode)->fd = fd; | |
595 | HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; | |
596 | d_instantiate(dentry, inode); | |
f1adc05e | 597 | return 0; |
1da177e4 LT |
598 | |
599 | out_put: | |
600 | iput(inode); | |
601 | out: | |
f1adc05e | 602 | return error; |
1da177e4 LT |
603 | } |
604 | ||
9e443bc3 JH |
605 | static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, |
606 | unsigned int flags) | |
1da177e4 LT |
607 | { |
608 | struct inode *inode; | |
609 | char *name; | |
610 | int err; | |
611 | ||
0a370e5d DH |
612 | inode = hostfs_iget(ino->i_sb); |
613 | if (IS_ERR(inode)) { | |
614 | err = PTR_ERR(inode); | |
1da177e4 | 615 | goto out; |
0a370e5d | 616 | } |
1da177e4 | 617 | |
1da177e4 | 618 | err = -ENOMEM; |
c5322220 | 619 | name = dentry_name(dentry); |
84b3db04 | 620 | if (name == NULL) |
1da177e4 LT |
621 | goto out_put; |
622 | ||
623 | err = read_name(inode, name); | |
5e2df28c | 624 | |
e9193059 | 625 | __putname(name); |
84b3db04 | 626 | if (err == -ENOENT) { |
1da177e4 LT |
627 | iput(inode); |
628 | inode = NULL; | |
629 | } | |
84b3db04 | 630 | else if (err) |
1da177e4 LT |
631 | goto out_put; |
632 | ||
633 | d_add(dentry, inode); | |
f1adc05e | 634 | return NULL; |
1da177e4 LT |
635 | |
636 | out_put: | |
637 | iput(inode); | |
638 | out: | |
f1adc05e | 639 | return ERR_PTR(err); |
1da177e4 LT |
640 | } |
641 | ||
9e443bc3 JH |
642 | static int hostfs_link(struct dentry *to, struct inode *ino, |
643 | struct dentry *from) | |
1da177e4 | 644 | { |
f1adc05e JD |
645 | char *from_name, *to_name; |
646 | int err; | |
1da177e4 | 647 | |
c5322220 | 648 | if ((from_name = dentry_name(from)) == NULL) |
f1adc05e | 649 | return -ENOMEM; |
c5322220 | 650 | to_name = dentry_name(to); |
84b3db04 | 651 | if (to_name == NULL) { |
e9193059 | 652 | __putname(from_name); |
f1adc05e | 653 | return -ENOMEM; |
1da177e4 | 654 | } |
f1adc05e | 655 | err = link_file(to_name, from_name); |
e9193059 AV |
656 | __putname(from_name); |
657 | __putname(to_name); | |
f1adc05e | 658 | return err; |
1da177e4 LT |
659 | } |
660 | ||
9e443bc3 | 661 | static int hostfs_unlink(struct inode *ino, struct dentry *dentry) |
1da177e4 LT |
662 | { |
663 | char *file; | |
664 | int err; | |
665 | ||
84b3db04 | 666 | if (append) |
f1adc05e | 667 | return -EPERM; |
1da177e4 | 668 | |
f8d7e187 AV |
669 | if ((file = dentry_name(dentry)) == NULL) |
670 | return -ENOMEM; | |
671 | ||
1da177e4 | 672 | err = unlink_file(file); |
e9193059 | 673 | __putname(file); |
f1adc05e | 674 | return err; |
1da177e4 LT |
675 | } |
676 | ||
9e443bc3 JH |
677 | static int hostfs_symlink(struct inode *ino, struct dentry *dentry, |
678 | const char *to) | |
1da177e4 LT |
679 | { |
680 | char *file; | |
681 | int err; | |
682 | ||
c5322220 | 683 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 684 | return -ENOMEM; |
1da177e4 | 685 | err = make_symlink(file, to); |
e9193059 | 686 | __putname(file); |
f1adc05e | 687 | return err; |
1da177e4 LT |
688 | } |
689 | ||
9e443bc3 | 690 | static int hostfs_mkdir(struct inode *ino, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
691 | { |
692 | char *file; | |
693 | int err; | |
694 | ||
c5322220 | 695 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 696 | return -ENOMEM; |
1da177e4 | 697 | err = do_mkdir(file, mode); |
e9193059 | 698 | __putname(file); |
f1adc05e | 699 | return err; |
1da177e4 LT |
700 | } |
701 | ||
9e443bc3 | 702 | static int hostfs_rmdir(struct inode *ino, struct dentry *dentry) |
1da177e4 LT |
703 | { |
704 | char *file; | |
705 | int err; | |
706 | ||
c5322220 | 707 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 708 | return -ENOMEM; |
1da177e4 | 709 | err = do_rmdir(file); |
e9193059 | 710 | __putname(file); |
f1adc05e | 711 | return err; |
1da177e4 LT |
712 | } |
713 | ||
1a67aafb | 714 | static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
1da177e4 LT |
715 | { |
716 | struct inode *inode; | |
717 | char *name; | |
0a370e5d | 718 | int err; |
1da177e4 | 719 | |
0a370e5d DH |
720 | inode = hostfs_iget(dir->i_sb); |
721 | if (IS_ERR(inode)) { | |
722 | err = PTR_ERR(inode); | |
1da177e4 | 723 | goto out; |
0a370e5d | 724 | } |
1da177e4 | 725 | |
1da177e4 | 726 | err = -ENOMEM; |
c5322220 | 727 | name = dentry_name(dentry); |
84b3db04 | 728 | if (name == NULL) |
1da177e4 LT |
729 | goto out_put; |
730 | ||
731 | init_special_inode(inode, mode, dev); | |
88f6cd0c | 732 | err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); |
e9193059 | 733 | if (!err) |
1da177e4 LT |
734 | goto out_free; |
735 | ||
736 | err = read_name(inode, name); | |
e9193059 | 737 | __putname(name); |
5e2df28c AV |
738 | if (err) |
739 | goto out_put; | |
84b3db04 | 740 | if (err) |
1da177e4 LT |
741 | goto out_put; |
742 | ||
743 | d_instantiate(dentry, inode); | |
f1adc05e | 744 | return 0; |
1da177e4 LT |
745 | |
746 | out_free: | |
e9193059 | 747 | __putname(name); |
1da177e4 LT |
748 | out_put: |
749 | iput(inode); | |
750 | out: | |
f1adc05e | 751 | return err; |
1da177e4 LT |
752 | } |
753 | ||
9a423bb6 MS |
754 | static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry, |
755 | struct inode *new_dir, struct dentry *new_dentry, | |
756 | unsigned int flags) | |
1da177e4 | 757 | { |
9a423bb6 | 758 | char *old_name, *new_name; |
1da177e4 LT |
759 | int err; |
760 | ||
9a423bb6 MS |
761 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) |
762 | return -EINVAL; | |
763 | ||
764 | old_name = dentry_name(old_dentry); | |
765 | if (old_name == NULL) | |
f1adc05e | 766 | return -ENOMEM; |
9a423bb6 MS |
767 | new_name = dentry_name(new_dentry); |
768 | if (new_name == NULL) { | |
769 | __putname(old_name); | |
f1adc05e | 770 | return -ENOMEM; |
1da177e4 | 771 | } |
9a423bb6 MS |
772 | if (!flags) |
773 | err = rename_file(old_name, new_name); | |
774 | else | |
775 | err = rename2_file(old_name, new_name, flags); | |
776 | ||
777 | __putname(old_name); | |
778 | __putname(new_name); | |
f1adc05e | 779 | return err; |
1da177e4 LT |
780 | } |
781 | ||
9e443bc3 | 782 | static int hostfs_permission(struct inode *ino, int desired) |
1da177e4 LT |
783 | { |
784 | char *name; | |
785 | int r = 0, w = 0, x = 0, err; | |
786 | ||
10556cb2 | 787 | if (desired & MAY_NOT_BLOCK) |
b74c79e9 NP |
788 | return -ECHILD; |
789 | ||
1da177e4 LT |
790 | if (desired & MAY_READ) r = 1; |
791 | if (desired & MAY_WRITE) w = 1; | |
792 | if (desired & MAY_EXEC) x = 1; | |
c5322220 | 793 | name = inode_name(ino); |
f1adc05e JD |
794 | if (name == NULL) |
795 | return -ENOMEM; | |
1da177e4 LT |
796 | |
797 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || | |
84b3db04 | 798 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) |
1da177e4 LT |
799 | err = 0; |
800 | else | |
801 | err = access_file(name, r, w, x); | |
e9193059 | 802 | __putname(name); |
84b3db04 | 803 | if (!err) |
2830ba7f | 804 | err = generic_permission(ino, desired); |
1da177e4 LT |
805 | return err; |
806 | } | |
807 | ||
9e443bc3 | 808 | static int hostfs_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 | 809 | { |
2b0143b5 | 810 | struct inode *inode = d_inode(dentry); |
1da177e4 LT |
811 | struct hostfs_iattr attrs; |
812 | char *name; | |
813 | int err; | |
814 | ||
1025774c | 815 | int fd = HOSTFS_I(inode)->fd; |
5822b7fa | 816 | |
1025774c | 817 | err = inode_change_ok(inode, attr); |
1da177e4 LT |
818 | if (err) |
819 | return err; | |
820 | ||
84b3db04 | 821 | if (append) |
1da177e4 LT |
822 | attr->ia_valid &= ~ATTR_SIZE; |
823 | ||
824 | attrs.ia_valid = 0; | |
84b3db04 | 825 | if (attr->ia_valid & ATTR_MODE) { |
1da177e4 LT |
826 | attrs.ia_valid |= HOSTFS_ATTR_MODE; |
827 | attrs.ia_mode = attr->ia_mode; | |
828 | } | |
84b3db04 | 829 | if (attr->ia_valid & ATTR_UID) { |
1da177e4 | 830 | attrs.ia_valid |= HOSTFS_ATTR_UID; |
29f82ae5 | 831 | attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid); |
1da177e4 | 832 | } |
84b3db04 | 833 | if (attr->ia_valid & ATTR_GID) { |
1da177e4 | 834 | attrs.ia_valid |= HOSTFS_ATTR_GID; |
29f82ae5 | 835 | attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid); |
1da177e4 | 836 | } |
84b3db04 | 837 | if (attr->ia_valid & ATTR_SIZE) { |
1da177e4 LT |
838 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; |
839 | attrs.ia_size = attr->ia_size; | |
840 | } | |
84b3db04 | 841 | if (attr->ia_valid & ATTR_ATIME) { |
1da177e4 LT |
842 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; |
843 | attrs.ia_atime = attr->ia_atime; | |
844 | } | |
84b3db04 | 845 | if (attr->ia_valid & ATTR_MTIME) { |
1da177e4 LT |
846 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; |
847 | attrs.ia_mtime = attr->ia_mtime; | |
848 | } | |
84b3db04 | 849 | if (attr->ia_valid & ATTR_CTIME) { |
1da177e4 LT |
850 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; |
851 | attrs.ia_ctime = attr->ia_ctime; | |
852 | } | |
84b3db04 | 853 | if (attr->ia_valid & ATTR_ATIME_SET) { |
1da177e4 LT |
854 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; |
855 | } | |
84b3db04 | 856 | if (attr->ia_valid & ATTR_MTIME_SET) { |
1da177e4 LT |
857 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; |
858 | } | |
c5322220 | 859 | name = dentry_name(dentry); |
84b3db04 | 860 | if (name == NULL) |
f1adc05e | 861 | return -ENOMEM; |
5822b7fa | 862 | err = set_attr(name, &attrs, fd); |
e9193059 | 863 | __putname(name); |
84b3db04 | 864 | if (err) |
f1adc05e | 865 | return err; |
1da177e4 | 866 | |
1025774c | 867 | if ((attr->ia_valid & ATTR_SIZE) && |
bc077320 | 868 | attr->ia_size != i_size_read(inode)) |
3be2be0a | 869 | truncate_setsize(inode, attr->ia_size); |
1025774c CH |
870 | |
871 | setattr_copy(inode, attr); | |
872 | mark_inode_dirty(inode); | |
873 | return 0; | |
1da177e4 LT |
874 | } |
875 | ||
92e1d5be | 876 | static const struct inode_operations hostfs_iops = { |
1da177e4 LT |
877 | .permission = hostfs_permission, |
878 | .setattr = hostfs_setattr, | |
1da177e4 LT |
879 | }; |
880 | ||
92e1d5be | 881 | static const struct inode_operations hostfs_dir_iops = { |
1da177e4 LT |
882 | .create = hostfs_create, |
883 | .lookup = hostfs_lookup, | |
884 | .link = hostfs_link, | |
885 | .unlink = hostfs_unlink, | |
886 | .symlink = hostfs_symlink, | |
887 | .mkdir = hostfs_mkdir, | |
888 | .rmdir = hostfs_rmdir, | |
889 | .mknod = hostfs_mknod, | |
9a423bb6 | 890 | .rename2 = hostfs_rename2, |
1da177e4 LT |
891 | .permission = hostfs_permission, |
892 | .setattr = hostfs_setattr, | |
1da177e4 LT |
893 | }; |
894 | ||
6e77137b | 895 | static const char *hostfs_follow_link(struct dentry *dentry, void **cookie) |
d0352d3e AV |
896 | { |
897 | char *link = __getname(); | |
898 | if (link) { | |
899 | char *path = dentry_name(dentry); | |
900 | int err = -ENOMEM; | |
901 | if (path) { | |
3b6036d1 | 902 | err = hostfs_do_readlink(path, link, PATH_MAX); |
d0352d3e AV |
903 | if (err == PATH_MAX) |
904 | err = -E2BIG; | |
e9193059 | 905 | __putname(path); |
d0352d3e AV |
906 | } |
907 | if (err < 0) { | |
908 | __putname(link); | |
680baacb | 909 | return ERR_PTR(err); |
d0352d3e AV |
910 | } |
911 | } else { | |
680baacb | 912 | return ERR_PTR(-ENOMEM); |
1da177e4 | 913 | } |
d0352d3e | 914 | |
680baacb | 915 | return *cookie = link; |
d0352d3e AV |
916 | } |
917 | ||
5f2c4179 | 918 | static void hostfs_put_link(struct inode *unused, void *cookie) |
d0352d3e | 919 | { |
680baacb | 920 | __putname(cookie); |
1da177e4 LT |
921 | } |
922 | ||
d0352d3e AV |
923 | static const struct inode_operations hostfs_link_iops = { |
924 | .readlink = generic_readlink, | |
925 | .follow_link = hostfs_follow_link, | |
926 | .put_link = hostfs_put_link, | |
1da177e4 LT |
927 | }; |
928 | ||
929 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) | |
930 | { | |
931 | struct inode *root_inode; | |
75e8defb | 932 | char *host_root_path, *req_root = d; |
1da177e4 LT |
933 | int err; |
934 | ||
935 | sb->s_blocksize = 1024; | |
936 | sb->s_blocksize_bits = 10; | |
937 | sb->s_magic = HOSTFS_SUPER_MAGIC; | |
938 | sb->s_op = &hostfs_sbops; | |
b26d4cd3 | 939 | sb->s_d_op = &simple_dentry_operations; |
752fa51e | 940 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 | 941 | |
a6eb0be6 | 942 | /* NULL is printed as <NULL> by sprintf: avoid that. */ |
75e8defb PBG |
943 | if (req_root == NULL) |
944 | req_root = ""; | |
1da177e4 LT |
945 | |
946 | err = -ENOMEM; | |
601d2c38 AV |
947 | sb->s_fs_info = host_root_path = |
948 | kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); | |
84b3db04 | 949 | if (host_root_path == NULL) |
1da177e4 LT |
950 | goto out; |
951 | ||
75e8defb | 952 | sprintf(host_root_path, "%s/%s", root_ino, req_root); |
1da177e4 | 953 | |
52b209f7 AV |
954 | root_inode = new_inode(sb); |
955 | if (!root_inode) | |
601d2c38 | 956 | goto out; |
1da177e4 | 957 | |
4754b825 AV |
958 | err = read_name(root_inode, host_root_path); |
959 | if (err) | |
960 | goto out_put; | |
52b209f7 | 961 | |
4754b825 | 962 | if (S_ISLNK(root_inode->i_mode)) { |
52b209f7 AV |
963 | char *name = follow_link(host_root_path); |
964 | if (IS_ERR(name)) | |
965 | err = PTR_ERR(name); | |
966 | else | |
967 | err = read_name(root_inode, name); | |
968 | kfree(name); | |
4754b825 AV |
969 | if (err) |
970 | goto out_put; | |
52b209f7 | 971 | } |
1da177e4 | 972 | |
1da177e4 | 973 | err = -ENOMEM; |
48fde701 | 974 | sb->s_root = d_make_root(root_inode); |
84b3db04 | 975 | if (sb->s_root == NULL) |
48fde701 | 976 | goto out; |
1da177e4 | 977 | |
f1adc05e | 978 | return 0; |
1da177e4 | 979 | |
f1adc05e JD |
980 | out_put: |
981 | iput(root_inode); | |
f1adc05e JD |
982 | out: |
983 | return err; | |
1da177e4 LT |
984 | } |
985 | ||
3c26ff6e | 986 | static struct dentry *hostfs_read_sb(struct file_system_type *type, |
454e2398 | 987 | int flags, const char *dev_name, |
3c26ff6e | 988 | void *data) |
1da177e4 | 989 | { |
3c26ff6e | 990 | return mount_nodev(type, flags, data, hostfs_fill_sb_common); |
1da177e4 LT |
991 | } |
992 | ||
601d2c38 AV |
993 | static void hostfs_kill_sb(struct super_block *s) |
994 | { | |
995 | kill_anon_super(s); | |
996 | kfree(s->s_fs_info); | |
997 | } | |
998 | ||
1da177e4 LT |
999 | static struct file_system_type hostfs_type = { |
1000 | .owner = THIS_MODULE, | |
1001 | .name = "hostfs", | |
3c26ff6e | 1002 | .mount = hostfs_read_sb, |
601d2c38 | 1003 | .kill_sb = hostfs_kill_sb, |
1da177e4 LT |
1004 | .fs_flags = 0, |
1005 | }; | |
3e64fe5b | 1006 | MODULE_ALIAS_FS("hostfs"); |
1da177e4 LT |
1007 | |
1008 | static int __init init_hostfs(void) | |
1009 | { | |
f1adc05e | 1010 | return register_filesystem(&hostfs_type); |
1da177e4 LT |
1011 | } |
1012 | ||
1013 | static void __exit exit_hostfs(void) | |
1014 | { | |
1015 | unregister_filesystem(&hostfs_type); | |
1016 | } | |
1017 | ||
1018 | module_init(init_hostfs) | |
1019 | module_exit(exit_hostfs) | |
1020 | MODULE_LICENSE("GPL"); |