Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com) |
| 3 | * Licensed under the GPL |
| 4 | * |
| 5 | * Ported the filesystem routines to 2.5. |
| 6 | * 2003-02-10 Petr Baudis <pasky@ucw.cz> |
| 7 | */ |
| 8 | |
| 9 | #include <linux/stddef.h> |
| 10 | #include <linux/fs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/module.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/slab.h> |
| 14 | #include <linux/pagemap.h> |
| 15 | #include <linux/blkdev.h> |
| 16 | #include <linux/list.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/statfs.h> |
| 18 | #include <linux/kdev_t.h> |
| 19 | #include <asm/uaccess.h> |
| 20 | #include "hostfs.h" |
| 21 | #include "kern_util.h" |
| 22 | #include "kern.h" |
| 23 | #include "user_util.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include "init.h" |
| 25 | |
| 26 | struct hostfs_inode_info { |
| 27 | char *host_filename; |
| 28 | int fd; |
| 29 | int mode; |
| 30 | struct inode vfs_inode; |
| 31 | }; |
| 32 | |
| 33 | static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) |
| 34 | { |
| 35 | return(list_entry(inode, struct hostfs_inode_info, vfs_inode)); |
| 36 | } |
| 37 | |
| 38 | #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_dentry->d_inode) |
| 39 | |
| 40 | int hostfs_d_delete(struct dentry *dentry) |
| 41 | { |
| 42 | return(1); |
| 43 | } |
| 44 | |
| 45 | struct dentry_operations hostfs_dentry_ops = { |
| 46 | .d_delete = hostfs_d_delete, |
| 47 | }; |
| 48 | |
| 49 | /* Changed in hostfs_args before the kernel starts running */ |
| 50 | static char *root_ino = "/"; |
| 51 | static int append = 0; |
| 52 | |
| 53 | #define HOSTFS_SUPER_MAGIC 0x00c0ffee |
| 54 | |
| 55 | static struct inode_operations hostfs_iops; |
| 56 | static struct inode_operations hostfs_dir_iops; |
| 57 | static struct address_space_operations hostfs_link_aops; |
| 58 | |
| 59 | #ifndef MODULE |
| 60 | static int __init hostfs_args(char *options, int *add) |
| 61 | { |
| 62 | char *ptr; |
| 63 | |
| 64 | ptr = strchr(options, ','); |
| 65 | if(ptr != NULL) |
| 66 | *ptr++ = '\0'; |
| 67 | if(*options != '\0') |
| 68 | root_ino = options; |
| 69 | |
| 70 | options = ptr; |
| 71 | while(options){ |
| 72 | ptr = strchr(options, ','); |
| 73 | if(ptr != NULL) |
| 74 | *ptr++ = '\0'; |
| 75 | if(*options != '\0'){ |
| 76 | if(!strcmp(options, "append")) |
| 77 | append = 1; |
| 78 | else printf("hostfs_args - unsupported option - %s\n", |
| 79 | options); |
| 80 | } |
| 81 | options = ptr; |
| 82 | } |
| 83 | return(0); |
| 84 | } |
| 85 | |
| 86 | __uml_setup("hostfs=", hostfs_args, |
| 87 | "hostfs=<root dir>,<flags>,...\n" |
| 88 | " This is used to set hostfs parameters. The root directory argument\n" |
| 89 | " is used to confine all hostfs mounts to within the specified directory\n" |
| 90 | " tree on the host. If this isn't specified, then a user inside UML can\n" |
| 91 | " mount anything on the host that's accessible to the user that's running\n" |
| 92 | " it.\n" |
| 93 | " The only flag currently supported is 'append', which specifies that all\n" |
| 94 | " files opened by hostfs will be opened in append mode.\n\n" |
| 95 | ); |
| 96 | #endif |
| 97 | |
| 98 | static char *dentry_name(struct dentry *dentry, int extra) |
| 99 | { |
| 100 | struct dentry *parent; |
| 101 | char *root, *name; |
| 102 | int len; |
| 103 | |
| 104 | len = 0; |
| 105 | parent = dentry; |
| 106 | while(parent->d_parent != parent){ |
| 107 | len += parent->d_name.len + 1; |
| 108 | parent = parent->d_parent; |
| 109 | } |
| 110 | |
| 111 | root = HOSTFS_I(parent->d_inode)->host_filename; |
| 112 | len += strlen(root); |
| 113 | name = kmalloc(len + extra + 1, GFP_KERNEL); |
| 114 | if(name == NULL) return(NULL); |
| 115 | |
| 116 | name[len] = '\0'; |
| 117 | parent = dentry; |
| 118 | while(parent->d_parent != parent){ |
| 119 | len -= parent->d_name.len + 1; |
| 120 | name[len] = '/'; |
| 121 | strncpy(&name[len + 1], parent->d_name.name, |
| 122 | parent->d_name.len); |
| 123 | parent = parent->d_parent; |
| 124 | } |
| 125 | strncpy(name, root, strlen(root)); |
| 126 | return(name); |
| 127 | } |
| 128 | |
| 129 | static char *inode_name(struct inode *ino, int extra) |
| 130 | { |
| 131 | struct dentry *dentry; |
| 132 | |
| 133 | dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); |
| 134 | return(dentry_name(dentry, extra)); |
| 135 | } |
| 136 | |
| 137 | static int read_name(struct inode *ino, char *name) |
| 138 | { |
| 139 | /* The non-int inode fields are copied into ints by stat_file and |
| 140 | * then copied into the inode because passing the actual pointers |
| 141 | * in and having them treated as int * breaks on big-endian machines |
| 142 | */ |
| 143 | int err; |
| 144 | int i_mode, i_nlink, i_blksize; |
| 145 | unsigned long long i_size; |
| 146 | unsigned long long i_ino; |
| 147 | unsigned long long i_blocks; |
| 148 | |
| 149 | err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, |
| 150 | &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, |
| 151 | &ino->i_ctime, &i_blksize, &i_blocks); |
| 152 | if(err) |
| 153 | return(err); |
| 154 | |
| 155 | ino->i_ino = i_ino; |
| 156 | ino->i_mode = i_mode; |
| 157 | ino->i_nlink = i_nlink; |
| 158 | ino->i_size = i_size; |
| 159 | ino->i_blksize = i_blksize; |
| 160 | ino->i_blocks = i_blocks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | return(0); |
| 162 | } |
| 163 | |
| 164 | static char *follow_link(char *link) |
| 165 | { |
| 166 | int len, n; |
| 167 | char *name, *resolved, *end; |
| 168 | |
| 169 | len = 64; |
| 170 | while(1){ |
| 171 | n = -ENOMEM; |
| 172 | name = kmalloc(len, GFP_KERNEL); |
| 173 | if(name == NULL) |
| 174 | goto out; |
| 175 | |
| 176 | n = do_readlink(link, name, len); |
| 177 | if(n < len) |
| 178 | break; |
| 179 | len *= 2; |
| 180 | kfree(name); |
| 181 | } |
| 182 | if(n < 0) |
| 183 | goto out_free; |
| 184 | |
| 185 | if(*name == '/') |
| 186 | return(name); |
| 187 | |
| 188 | end = strrchr(link, '/'); |
| 189 | if(end == NULL) |
| 190 | return(name); |
| 191 | |
| 192 | *(end + 1) = '\0'; |
| 193 | len = strlen(link) + strlen(name) + 1; |
| 194 | |
| 195 | resolved = kmalloc(len, GFP_KERNEL); |
| 196 | if(resolved == NULL){ |
| 197 | n = -ENOMEM; |
| 198 | goto out_free; |
| 199 | } |
| 200 | |
| 201 | sprintf(resolved, "%s%s", link, name); |
| 202 | kfree(name); |
| 203 | kfree(link); |
| 204 | return(resolved); |
| 205 | |
| 206 | out_free: |
| 207 | kfree(name); |
| 208 | out: |
| 209 | return(ERR_PTR(n)); |
| 210 | } |
| 211 | |
| 212 | static int read_inode(struct inode *ino) |
| 213 | { |
| 214 | char *name; |
| 215 | int err = 0; |
| 216 | |
| 217 | /* Unfortunately, we are called from iget() when we don't have a dentry |
| 218 | * allocated yet. |
| 219 | */ |
| 220 | if(list_empty(&ino->i_dentry)) |
| 221 | goto out; |
| 222 | |
| 223 | err = -ENOMEM; |
| 224 | name = inode_name(ino, 0); |
| 225 | if(name == NULL) |
| 226 | goto out; |
| 227 | |
| 228 | if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){ |
| 229 | name = follow_link(name); |
| 230 | if(IS_ERR(name)){ |
| 231 | err = PTR_ERR(name); |
| 232 | goto out; |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | err = read_name(ino, name); |
| 237 | kfree(name); |
| 238 | out: |
| 239 | return(err); |
| 240 | } |
| 241 | |
| 242 | int hostfs_statfs(struct super_block *sb, struct kstatfs *sf) |
| 243 | { |
| 244 | /* do_statfs uses struct statfs64 internally, but the linux kernel |
| 245 | * struct statfs still has 32-bit versions for most of these fields, |
| 246 | * so we convert them here |
| 247 | */ |
| 248 | int err; |
| 249 | long long f_blocks; |
| 250 | long long f_bfree; |
| 251 | long long f_bavail; |
| 252 | long long f_files; |
| 253 | long long f_ffree; |
| 254 | |
| 255 | err = do_statfs(HOSTFS_I(sb->s_root->d_inode)->host_filename, |
| 256 | &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, |
| 257 | &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), |
| 258 | &sf->f_namelen, sf->f_spare); |
| 259 | if(err) return(err); |
| 260 | sf->f_blocks = f_blocks; |
| 261 | sf->f_bfree = f_bfree; |
| 262 | sf->f_bavail = f_bavail; |
| 263 | sf->f_files = f_files; |
| 264 | sf->f_ffree = f_ffree; |
| 265 | sf->f_type = HOSTFS_SUPER_MAGIC; |
| 266 | return(0); |
| 267 | } |
| 268 | |
| 269 | static struct inode *hostfs_alloc_inode(struct super_block *sb) |
| 270 | { |
| 271 | struct hostfs_inode_info *hi; |
| 272 | |
| 273 | hi = kmalloc(sizeof(*hi), GFP_KERNEL); |
| 274 | if(hi == NULL) |
| 275 | return(NULL); |
| 276 | |
| 277 | *hi = ((struct hostfs_inode_info) { .host_filename = NULL, |
| 278 | .fd = -1, |
| 279 | .mode = 0 }); |
| 280 | inode_init_once(&hi->vfs_inode); |
| 281 | return(&hi->vfs_inode); |
| 282 | } |
| 283 | |
| 284 | static void hostfs_delete_inode(struct inode *inode) |
| 285 | { |
Mark Fasheh | fef2665 | 2005-09-09 13:01:31 -0700 | [diff] [blame] | 286 | truncate_inode_pages(&inode->i_data, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | if(HOSTFS_I(inode)->fd != -1) { |
| 288 | close_file(&HOSTFS_I(inode)->fd); |
| 289 | HOSTFS_I(inode)->fd = -1; |
| 290 | } |
| 291 | clear_inode(inode); |
| 292 | } |
| 293 | |
| 294 | static void hostfs_destroy_inode(struct inode *inode) |
| 295 | { |
Jesper Juhl | f99d49a | 2005-11-07 01:01:34 -0800 | [diff] [blame] | 296 | kfree(HOSTFS_I(inode)->host_filename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | |
| 298 | /*XXX: This should not happen, probably. The check is here for |
| 299 | * additional safety.*/ |
| 300 | if(HOSTFS_I(inode)->fd != -1) { |
| 301 | close_file(&HOSTFS_I(inode)->fd); |
| 302 | printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); |
| 303 | } |
| 304 | |
| 305 | kfree(HOSTFS_I(inode)); |
| 306 | } |
| 307 | |
| 308 | static void hostfs_read_inode(struct inode *inode) |
| 309 | { |
| 310 | read_inode(inode); |
| 311 | } |
| 312 | |
| 313 | static struct super_operations hostfs_sbops = { |
| 314 | .alloc_inode = hostfs_alloc_inode, |
| 315 | .drop_inode = generic_delete_inode, |
| 316 | .delete_inode = hostfs_delete_inode, |
| 317 | .destroy_inode = hostfs_destroy_inode, |
| 318 | .read_inode = hostfs_read_inode, |
| 319 | .statfs = hostfs_statfs, |
| 320 | }; |
| 321 | |
| 322 | int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) |
| 323 | { |
| 324 | void *dir; |
| 325 | char *name; |
| 326 | unsigned long long next, ino; |
| 327 | int error, len; |
| 328 | |
| 329 | name = dentry_name(file->f_dentry, 0); |
| 330 | if(name == NULL) return(-ENOMEM); |
| 331 | dir = open_dir(name, &error); |
| 332 | kfree(name); |
| 333 | if(dir == NULL) return(-error); |
| 334 | next = file->f_pos; |
| 335 | while((name = read_dir(dir, &next, &ino, &len)) != NULL){ |
| 336 | error = (*filldir)(ent, name, len, file->f_pos, |
| 337 | ino, DT_UNKNOWN); |
| 338 | if(error) break; |
| 339 | file->f_pos = next; |
| 340 | } |
| 341 | close_dir(dir); |
| 342 | return(0); |
| 343 | } |
| 344 | |
| 345 | int hostfs_file_open(struct inode *ino, struct file *file) |
| 346 | { |
| 347 | char *name; |
| 348 | int mode = 0, r = 0, w = 0, fd; |
| 349 | |
| 350 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); |
| 351 | if((mode & HOSTFS_I(ino)->mode) == mode) |
| 352 | return(0); |
| 353 | |
| 354 | /* The file may already have been opened, but with the wrong access, |
| 355 | * so this resets things and reopens the file with the new access. |
| 356 | */ |
| 357 | if(HOSTFS_I(ino)->fd != -1){ |
| 358 | close_file(&HOSTFS_I(ino)->fd); |
| 359 | HOSTFS_I(ino)->fd = -1; |
| 360 | } |
| 361 | |
| 362 | HOSTFS_I(ino)->mode |= mode; |
| 363 | if(HOSTFS_I(ino)->mode & FMODE_READ) |
| 364 | r = 1; |
| 365 | if(HOSTFS_I(ino)->mode & FMODE_WRITE) |
| 366 | w = 1; |
| 367 | if(w) |
| 368 | r = 1; |
| 369 | |
| 370 | name = dentry_name(file->f_dentry, 0); |
| 371 | if(name == NULL) |
| 372 | return(-ENOMEM); |
| 373 | |
| 374 | fd = open_file(name, r, w, append); |
| 375 | kfree(name); |
| 376 | if(fd < 0) return(fd); |
| 377 | FILE_HOSTFS_I(file)->fd = fd; |
| 378 | |
| 379 | return(0); |
| 380 | } |
| 381 | |
| 382 | int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync) |
| 383 | { |
Paolo 'Blaisorblade' Giarrusso | a2d76bd | 2005-07-28 21:16:15 -0700 | [diff] [blame] | 384 | return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | } |
| 386 | |
| 387 | static struct file_operations hostfs_file_fops = { |
| 388 | .llseek = generic_file_llseek, |
| 389 | .read = generic_file_read, |
| 390 | .sendfile = generic_file_sendfile, |
| 391 | .aio_read = generic_file_aio_read, |
| 392 | .aio_write = generic_file_aio_write, |
| 393 | .readv = generic_file_readv, |
| 394 | .writev = generic_file_writev, |
| 395 | .write = generic_file_write, |
| 396 | .mmap = generic_file_mmap, |
| 397 | .open = hostfs_file_open, |
| 398 | .release = NULL, |
| 399 | .fsync = hostfs_fsync, |
| 400 | }; |
| 401 | |
| 402 | static struct file_operations hostfs_dir_fops = { |
| 403 | .llseek = generic_file_llseek, |
| 404 | .readdir = hostfs_readdir, |
| 405 | .read = generic_read_dir, |
| 406 | }; |
| 407 | |
| 408 | int hostfs_writepage(struct page *page, struct writeback_control *wbc) |
| 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); |
| 425 | if(err != count){ |
| 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 | |
| 444 | int hostfs_readpage(struct file *file, struct page *page) |
| 445 | { |
| 446 | char *buffer; |
| 447 | long long start; |
| 448 | int err = 0; |
| 449 | |
| 450 | start = (long long) page->index << PAGE_CACHE_SHIFT; |
| 451 | buffer = kmap(page); |
| 452 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, |
| 453 | PAGE_CACHE_SIZE); |
| 454 | if(err < 0) goto out; |
| 455 | |
| 456 | memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); |
| 457 | |
| 458 | flush_dcache_page(page); |
| 459 | SetPageUptodate(page); |
| 460 | if (PageError(page)) ClearPageError(page); |
| 461 | err = 0; |
| 462 | out: |
| 463 | kunmap(page); |
| 464 | unlock_page(page); |
| 465 | return(err); |
| 466 | } |
| 467 | |
| 468 | int hostfs_prepare_write(struct file *file, struct page *page, |
| 469 | unsigned int from, unsigned int to) |
| 470 | { |
| 471 | char *buffer; |
| 472 | long long start, tmp; |
| 473 | int err; |
| 474 | |
| 475 | start = (long long) page->index << PAGE_CACHE_SHIFT; |
| 476 | buffer = kmap(page); |
| 477 | if(from != 0){ |
| 478 | tmp = start; |
| 479 | err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer, |
| 480 | from); |
| 481 | if(err < 0) goto out; |
| 482 | } |
| 483 | if(to != PAGE_CACHE_SIZE){ |
| 484 | start += to; |
| 485 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to, |
| 486 | PAGE_CACHE_SIZE - to); |
| 487 | if(err < 0) goto out; |
| 488 | } |
| 489 | err = 0; |
| 490 | out: |
| 491 | kunmap(page); |
| 492 | return(err); |
| 493 | } |
| 494 | |
| 495 | int hostfs_commit_write(struct file *file, struct page *page, unsigned from, |
| 496 | unsigned to) |
| 497 | { |
| 498 | struct address_space *mapping = page->mapping; |
| 499 | struct inode *inode = mapping->host; |
| 500 | char *buffer; |
| 501 | long long start; |
| 502 | int err = 0; |
| 503 | |
Paolo 'Blaisorblade' Giarrusso | 30f04a4 | 2005-12-29 17:39:57 +0100 | [diff] [blame] | 504 | start = (((long long) page->index) << PAGE_CACHE_SHIFT) + from; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | buffer = kmap(page); |
| 506 | err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from, |
| 507 | to - from); |
| 508 | if(err > 0) err = 0; |
Paolo 'Blaisorblade' Giarrusso | 30f04a4 | 2005-12-29 17:39:57 +0100 | [diff] [blame] | 509 | |
| 510 | /* Actually, if !err, write_file has added to-from to start, so, despite |
| 511 | * the appearance, we are comparing i_size against the _last_ written |
| 512 | * location, as we should. */ |
| 513 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 514 | if(!err && (start > inode->i_size)) |
| 515 | inode->i_size = start; |
| 516 | |
| 517 | kunmap(page); |
| 518 | return(err); |
| 519 | } |
| 520 | |
| 521 | static struct address_space_operations hostfs_aops = { |
| 522 | .writepage = hostfs_writepage, |
| 523 | .readpage = hostfs_readpage, |
Paolo 'Blaisorblade' Giarrusso | ffa0aea | 2005-05-01 08:58:56 -0700 | [diff] [blame] | 524 | .set_page_dirty = __set_page_dirty_nobuffers, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 525 | .prepare_write = hostfs_prepare_write, |
| 526 | .commit_write = hostfs_commit_write |
| 527 | }; |
| 528 | |
| 529 | static int init_inode(struct inode *inode, struct dentry *dentry) |
| 530 | { |
| 531 | char *name; |
| 532 | int type, err = -ENOMEM; |
| 533 | int maj, min; |
| 534 | dev_t rdev = 0; |
| 535 | |
| 536 | if(dentry){ |
| 537 | name = dentry_name(dentry, 0); |
| 538 | if(name == NULL) |
| 539 | goto out; |
| 540 | type = file_type(name, &maj, &min); |
| 541 | /*Reencode maj and min with the kernel encoding.*/ |
| 542 | rdev = MKDEV(maj, min); |
| 543 | kfree(name); |
| 544 | } |
| 545 | else type = OS_TYPE_DIR; |
| 546 | |
| 547 | err = 0; |
| 548 | if(type == OS_TYPE_SYMLINK) |
| 549 | inode->i_op = &page_symlink_inode_operations; |
| 550 | else if(type == OS_TYPE_DIR) |
| 551 | inode->i_op = &hostfs_dir_iops; |
| 552 | else inode->i_op = &hostfs_iops; |
| 553 | |
| 554 | if(type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops; |
| 555 | else inode->i_fop = &hostfs_file_fops; |
| 556 | |
| 557 | if(type == OS_TYPE_SYMLINK) |
| 558 | inode->i_mapping->a_ops = &hostfs_link_aops; |
| 559 | else inode->i_mapping->a_ops = &hostfs_aops; |
| 560 | |
| 561 | switch (type) { |
| 562 | case OS_TYPE_CHARDEV: |
| 563 | init_special_inode(inode, S_IFCHR, rdev); |
| 564 | break; |
| 565 | case OS_TYPE_BLOCKDEV: |
| 566 | init_special_inode(inode, S_IFBLK, rdev); |
| 567 | break; |
| 568 | case OS_TYPE_FIFO: |
| 569 | init_special_inode(inode, S_IFIFO, 0); |
| 570 | break; |
| 571 | case OS_TYPE_SOCK: |
| 572 | init_special_inode(inode, S_IFSOCK, 0); |
| 573 | break; |
| 574 | } |
| 575 | out: |
| 576 | return(err); |
| 577 | } |
| 578 | |
| 579 | int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, |
| 580 | struct nameidata *nd) |
| 581 | { |
| 582 | struct inode *inode; |
| 583 | char *name; |
| 584 | int error, fd; |
| 585 | |
| 586 | error = -ENOMEM; |
| 587 | inode = iget(dir->i_sb, 0); |
| 588 | if(inode == NULL) goto out; |
| 589 | |
| 590 | error = init_inode(inode, dentry); |
| 591 | if(error) |
| 592 | goto out_put; |
| 593 | |
| 594 | error = -ENOMEM; |
| 595 | name = dentry_name(dentry, 0); |
| 596 | if(name == NULL) |
| 597 | goto out_put; |
| 598 | |
| 599 | fd = file_create(name, |
| 600 | mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, |
| 601 | mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, |
| 602 | mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); |
| 603 | if(fd < 0) |
| 604 | error = fd; |
| 605 | else error = read_name(inode, name); |
| 606 | |
| 607 | kfree(name); |
| 608 | if(error) |
| 609 | goto out_put; |
| 610 | |
| 611 | HOSTFS_I(inode)->fd = fd; |
| 612 | HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; |
| 613 | d_instantiate(dentry, inode); |
| 614 | return(0); |
| 615 | |
| 616 | out_put: |
| 617 | iput(inode); |
| 618 | out: |
| 619 | return(error); |
| 620 | } |
| 621 | |
| 622 | struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, |
| 623 | struct nameidata *nd) |
| 624 | { |
| 625 | struct inode *inode; |
| 626 | char *name; |
| 627 | int err; |
| 628 | |
| 629 | err = -ENOMEM; |
| 630 | inode = iget(ino->i_sb, 0); |
| 631 | if(inode == NULL) |
| 632 | goto out; |
| 633 | |
| 634 | err = init_inode(inode, dentry); |
| 635 | if(err) |
| 636 | goto out_put; |
| 637 | |
| 638 | err = -ENOMEM; |
| 639 | name = dentry_name(dentry, 0); |
| 640 | if(name == NULL) |
| 641 | goto out_put; |
| 642 | |
| 643 | err = read_name(inode, name); |
| 644 | kfree(name); |
| 645 | if(err == -ENOENT){ |
| 646 | iput(inode); |
| 647 | inode = NULL; |
| 648 | } |
| 649 | else if(err) |
| 650 | goto out_put; |
| 651 | |
| 652 | d_add(dentry, inode); |
| 653 | dentry->d_op = &hostfs_dentry_ops; |
| 654 | return(NULL); |
| 655 | |
| 656 | out_put: |
| 657 | iput(inode); |
| 658 | out: |
| 659 | return(ERR_PTR(err)); |
| 660 | } |
| 661 | |
| 662 | static char *inode_dentry_name(struct inode *ino, struct dentry *dentry) |
| 663 | { |
| 664 | char *file; |
| 665 | int len; |
| 666 | |
| 667 | file = inode_name(ino, dentry->d_name.len + 1); |
| 668 | if(file == NULL) return(NULL); |
| 669 | strcat(file, "/"); |
| 670 | len = strlen(file); |
| 671 | strncat(file, dentry->d_name.name, dentry->d_name.len); |
| 672 | file[len + dentry->d_name.len] = '\0'; |
| 673 | return(file); |
| 674 | } |
| 675 | |
| 676 | int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) |
| 677 | { |
| 678 | char *from_name, *to_name; |
| 679 | int err; |
| 680 | |
| 681 | if((from_name = inode_dentry_name(ino, from)) == NULL) |
| 682 | return(-ENOMEM); |
| 683 | to_name = dentry_name(to, 0); |
| 684 | if(to_name == NULL){ |
| 685 | kfree(from_name); |
| 686 | return(-ENOMEM); |
| 687 | } |
| 688 | err = link_file(to_name, from_name); |
| 689 | kfree(from_name); |
| 690 | kfree(to_name); |
| 691 | return(err); |
| 692 | } |
| 693 | |
| 694 | int hostfs_unlink(struct inode *ino, struct dentry *dentry) |
| 695 | { |
| 696 | char *file; |
| 697 | int err; |
| 698 | |
| 699 | if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM); |
| 700 | if(append) |
| 701 | return(-EPERM); |
| 702 | |
| 703 | err = unlink_file(file); |
| 704 | kfree(file); |
| 705 | return(err); |
| 706 | } |
| 707 | |
| 708 | int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) |
| 709 | { |
| 710 | char *file; |
| 711 | int err; |
| 712 | |
| 713 | if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM); |
| 714 | err = make_symlink(file, to); |
| 715 | kfree(file); |
| 716 | return(err); |
| 717 | } |
| 718 | |
| 719 | int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) |
| 720 | { |
| 721 | char *file; |
| 722 | int err; |
| 723 | |
| 724 | if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM); |
| 725 | err = do_mkdir(file, mode); |
| 726 | kfree(file); |
| 727 | return(err); |
| 728 | } |
| 729 | |
| 730 | int hostfs_rmdir(struct inode *ino, struct dentry *dentry) |
| 731 | { |
| 732 | char *file; |
| 733 | int err; |
| 734 | |
| 735 | if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM); |
| 736 | err = do_rmdir(file); |
| 737 | kfree(file); |
| 738 | return(err); |
| 739 | } |
| 740 | |
| 741 | int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) |
| 742 | { |
| 743 | struct inode *inode; |
| 744 | char *name; |
| 745 | int err = -ENOMEM; |
| 746 | |
| 747 | inode = iget(dir->i_sb, 0); |
| 748 | if(inode == NULL) |
| 749 | goto out; |
| 750 | |
| 751 | err = init_inode(inode, dentry); |
| 752 | if(err) |
| 753 | goto out_put; |
| 754 | |
| 755 | err = -ENOMEM; |
| 756 | name = dentry_name(dentry, 0); |
| 757 | if(name == NULL) |
| 758 | goto out_put; |
| 759 | |
| 760 | init_special_inode(inode, mode, dev); |
| 761 | err = do_mknod(name, mode, dev); |
| 762 | if(err) |
| 763 | goto out_free; |
| 764 | |
| 765 | err = read_name(inode, name); |
| 766 | kfree(name); |
| 767 | if(err) |
| 768 | goto out_put; |
| 769 | |
| 770 | d_instantiate(dentry, inode); |
| 771 | return(0); |
| 772 | |
| 773 | out_free: |
| 774 | kfree(name); |
| 775 | out_put: |
| 776 | iput(inode); |
| 777 | out: |
| 778 | return(err); |
| 779 | } |
| 780 | |
| 781 | int hostfs_rename(struct inode *from_ino, struct dentry *from, |
| 782 | struct inode *to_ino, struct dentry *to) |
| 783 | { |
| 784 | char *from_name, *to_name; |
| 785 | int err; |
| 786 | |
| 787 | if((from_name = inode_dentry_name(from_ino, from)) == NULL) |
| 788 | return(-ENOMEM); |
| 789 | if((to_name = inode_dentry_name(to_ino, to)) == NULL){ |
| 790 | kfree(from_name); |
| 791 | return(-ENOMEM); |
| 792 | } |
| 793 | err = rename_file(from_name, to_name); |
| 794 | kfree(from_name); |
| 795 | kfree(to_name); |
| 796 | return(err); |
| 797 | } |
| 798 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd) |
| 800 | { |
| 801 | char *name; |
| 802 | int r = 0, w = 0, x = 0, err; |
| 803 | |
| 804 | if (desired & MAY_READ) r = 1; |
| 805 | if (desired & MAY_WRITE) w = 1; |
| 806 | if (desired & MAY_EXEC) x = 1; |
| 807 | name = inode_name(ino, 0); |
| 808 | if (name == NULL) return(-ENOMEM); |
| 809 | |
| 810 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || |
| 811 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) |
| 812 | err = 0; |
| 813 | else |
| 814 | err = access_file(name, r, w, x); |
| 815 | kfree(name); |
| 816 | if(!err) |
| 817 | err = generic_permission(ino, desired, NULL); |
| 818 | return err; |
| 819 | } |
| 820 | |
| 821 | int hostfs_setattr(struct dentry *dentry, struct iattr *attr) |
| 822 | { |
| 823 | struct hostfs_iattr attrs; |
| 824 | char *name; |
| 825 | int err; |
| 826 | |
| 827 | err = inode_change_ok(dentry->d_inode, attr); |
| 828 | if (err) |
| 829 | return err; |
| 830 | |
| 831 | if(append) |
| 832 | attr->ia_valid &= ~ATTR_SIZE; |
| 833 | |
| 834 | attrs.ia_valid = 0; |
| 835 | if(attr->ia_valid & ATTR_MODE){ |
| 836 | attrs.ia_valid |= HOSTFS_ATTR_MODE; |
| 837 | attrs.ia_mode = attr->ia_mode; |
| 838 | } |
| 839 | if(attr->ia_valid & ATTR_UID){ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 840 | attrs.ia_valid |= HOSTFS_ATTR_UID; |
| 841 | attrs.ia_uid = attr->ia_uid; |
| 842 | } |
| 843 | if(attr->ia_valid & ATTR_GID){ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | attrs.ia_valid |= HOSTFS_ATTR_GID; |
| 845 | attrs.ia_gid = attr->ia_gid; |
| 846 | } |
| 847 | if(attr->ia_valid & ATTR_SIZE){ |
| 848 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; |
| 849 | attrs.ia_size = attr->ia_size; |
| 850 | } |
| 851 | if(attr->ia_valid & ATTR_ATIME){ |
| 852 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; |
| 853 | attrs.ia_atime = attr->ia_atime; |
| 854 | } |
| 855 | if(attr->ia_valid & ATTR_MTIME){ |
| 856 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; |
| 857 | attrs.ia_mtime = attr->ia_mtime; |
| 858 | } |
| 859 | if(attr->ia_valid & ATTR_CTIME){ |
| 860 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; |
| 861 | attrs.ia_ctime = attr->ia_ctime; |
| 862 | } |
| 863 | if(attr->ia_valid & ATTR_ATIME_SET){ |
| 864 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; |
| 865 | } |
| 866 | if(attr->ia_valid & ATTR_MTIME_SET){ |
| 867 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; |
| 868 | } |
| 869 | name = dentry_name(dentry, 0); |
| 870 | if(name == NULL) return(-ENOMEM); |
| 871 | err = set_attr(name, &attrs); |
| 872 | kfree(name); |
| 873 | if(err) |
| 874 | return(err); |
| 875 | |
| 876 | return(inode_setattr(dentry->d_inode, attr)); |
| 877 | } |
| 878 | |
| 879 | int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry, |
| 880 | struct kstat *stat) |
| 881 | { |
| 882 | generic_fillattr(dentry->d_inode, stat); |
| 883 | return(0); |
| 884 | } |
| 885 | |
| 886 | static struct inode_operations hostfs_iops = { |
| 887 | .create = hostfs_create, |
| 888 | .link = hostfs_link, |
| 889 | .unlink = hostfs_unlink, |
| 890 | .symlink = hostfs_symlink, |
| 891 | .mkdir = hostfs_mkdir, |
| 892 | .rmdir = hostfs_rmdir, |
| 893 | .mknod = hostfs_mknod, |
| 894 | .rename = hostfs_rename, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 895 | .permission = hostfs_permission, |
| 896 | .setattr = hostfs_setattr, |
| 897 | .getattr = hostfs_getattr, |
| 898 | }; |
| 899 | |
| 900 | static struct inode_operations hostfs_dir_iops = { |
| 901 | .create = hostfs_create, |
| 902 | .lookup = hostfs_lookup, |
| 903 | .link = hostfs_link, |
| 904 | .unlink = hostfs_unlink, |
| 905 | .symlink = hostfs_symlink, |
| 906 | .mkdir = hostfs_mkdir, |
| 907 | .rmdir = hostfs_rmdir, |
| 908 | .mknod = hostfs_mknod, |
| 909 | .rename = hostfs_rename, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 910 | .permission = hostfs_permission, |
| 911 | .setattr = hostfs_setattr, |
| 912 | .getattr = hostfs_getattr, |
| 913 | }; |
| 914 | |
| 915 | int hostfs_link_readpage(struct file *file, struct page *page) |
| 916 | { |
| 917 | char *buffer, *name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 918 | int err; |
| 919 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 920 | buffer = kmap(page); |
| 921 | name = inode_name(page->mapping->host, 0); |
| 922 | if(name == NULL) return(-ENOMEM); |
| 923 | err = do_readlink(name, buffer, PAGE_CACHE_SIZE); |
| 924 | kfree(name); |
| 925 | if(err == PAGE_CACHE_SIZE) |
| 926 | err = -E2BIG; |
| 927 | else if(err > 0){ |
| 928 | flush_dcache_page(page); |
| 929 | SetPageUptodate(page); |
| 930 | if (PageError(page)) ClearPageError(page); |
| 931 | err = 0; |
| 932 | } |
| 933 | kunmap(page); |
| 934 | unlock_page(page); |
| 935 | return(err); |
| 936 | } |
| 937 | |
| 938 | static struct address_space_operations hostfs_link_aops = { |
| 939 | .readpage = hostfs_link_readpage, |
| 940 | }; |
| 941 | |
| 942 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) |
| 943 | { |
| 944 | struct inode *root_inode; |
| 945 | char *name, *data = d; |
| 946 | int err; |
| 947 | |
| 948 | sb->s_blocksize = 1024; |
| 949 | sb->s_blocksize_bits = 10; |
| 950 | sb->s_magic = HOSTFS_SUPER_MAGIC; |
| 951 | sb->s_op = &hostfs_sbops; |
| 952 | |
| 953 | if((data == NULL) || (*data == '\0')) |
| 954 | data = root_ino; |
| 955 | |
| 956 | err = -ENOMEM; |
| 957 | name = kmalloc(strlen(data) + 1, GFP_KERNEL); |
| 958 | if(name == NULL) |
| 959 | goto out; |
| 960 | |
| 961 | strcpy(name, data); |
| 962 | |
| 963 | root_inode = iget(sb, 0); |
| 964 | if(root_inode == NULL) |
| 965 | goto out_free; |
| 966 | |
| 967 | err = init_inode(root_inode, NULL); |
| 968 | if(err) |
| 969 | goto out_put; |
| 970 | |
| 971 | HOSTFS_I(root_inode)->host_filename = name; |
| 972 | |
| 973 | err = -ENOMEM; |
| 974 | sb->s_root = d_alloc_root(root_inode); |
| 975 | if(sb->s_root == NULL) |
| 976 | goto out_put; |
| 977 | |
| 978 | err = read_inode(root_inode); |
Jeff Dike | 51a1411 | 2005-05-05 16:15:34 -0700 | [diff] [blame] | 979 | if(err){ |
| 980 | /* No iput in this case because the dput does that for us */ |
| 981 | dput(sb->s_root); |
| 982 | sb->s_root = NULL; |
| 983 | goto out_free; |
| 984 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 985 | |
| 986 | return(0); |
| 987 | |
| 988 | out_put: |
Jeff Dike | 51a1411 | 2005-05-05 16:15:34 -0700 | [diff] [blame] | 989 | iput(root_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 990 | out_free: |
| 991 | kfree(name); |
| 992 | out: |
| 993 | return(err); |
| 994 | } |
| 995 | |
| 996 | static struct super_block *hostfs_read_sb(struct file_system_type *type, |
| 997 | int flags, const char *dev_name, |
| 998 | void *data) |
| 999 | { |
| 1000 | return(get_sb_nodev(type, flags, data, hostfs_fill_sb_common)); |
| 1001 | } |
| 1002 | |
| 1003 | static struct file_system_type hostfs_type = { |
| 1004 | .owner = THIS_MODULE, |
| 1005 | .name = "hostfs", |
| 1006 | .get_sb = hostfs_read_sb, |
| 1007 | .kill_sb = kill_anon_super, |
| 1008 | .fs_flags = 0, |
| 1009 | }; |
| 1010 | |
| 1011 | static int __init init_hostfs(void) |
| 1012 | { |
| 1013 | return(register_filesystem(&hostfs_type)); |
| 1014 | } |
| 1015 | |
| 1016 | static void __exit exit_hostfs(void) |
| 1017 | { |
| 1018 | unregister_filesystem(&hostfs_type); |
| 1019 | } |
| 1020 | |
| 1021 | module_init(init_hostfs) |
| 1022 | module_exit(exit_hostfs) |
| 1023 | MODULE_LICENSE("GPL"); |
| 1024 | |
| 1025 | /* |
| 1026 | * Overrides for Emacs so that we follow Linus's tabbing style. |
| 1027 | * Emacs will notice this stuff at the end of the file and automatically |
| 1028 | * adjust the settings for this buffer only. This must remain at the end |
| 1029 | * of the file. |
| 1030 | * --------------------------------------------------------------------------- |
| 1031 | * Local variables: |
| 1032 | * c-file-style: "linux" |
| 1033 | * End: |
| 1034 | */ |