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59#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
60
61#include <linux/module.h>
62#include <linux/string.h>
63#include <linux/fs.h>
64#include <linux/time.h>
65#include <linux/slab.h>
66#include <linux/init.h>
67#include <linux/blkdev.h>
68#include <linux/parser.h>
69#include <linux/mount.h>
70#include <linux/namei.h>
71#include <linux/statfs.h>
72#include <linux/mtd/super.h>
73#include <linux/ctype.h>
74#include <linux/highmem.h>
75#include <linux/pagemap.h>
76#include <linux/uaccess.h>
77#include <linux/major.h>
78#include "internal.h"
79
80static struct kmem_cache *romfs_inode_cachep;
81
82static const umode_t romfs_modemap[8] = {
83 0,
84 S_IFDIR | 0644,
85 S_IFREG | 0644,
86 S_IFLNK | 0777,
87 S_IFBLK | 0600,
88 S_IFCHR | 0600,
89 S_IFSOCK | 0644,
90 S_IFIFO | 0644
91};
92
93static const unsigned char romfs_dtype_table[] = {
94 DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_SOCK, DT_FIFO
95};
96
97static struct inode *romfs_iget(struct super_block *sb, unsigned long pos);
98
99
100
101
102static int romfs_readpage(struct file *file, struct page *page)
103{
104 struct inode *inode = page->mapping->host;
105 loff_t offset, size;
106 unsigned long fillsize, pos;
107 void *buf;
108 int ret;
109
110 buf = kmap(page);
111 if (!buf)
112 return -ENOMEM;
113
114
115 offset = page_offset(page);
116 size = i_size_read(inode);
117 fillsize = 0;
118 ret = 0;
119 if (offset < size) {
120 size -= offset;
121 fillsize = size > PAGE_SIZE ? PAGE_SIZE : size;
122
123 pos = ROMFS_I(inode)->i_dataoffset + offset;
124
125 ret = romfs_dev_read(inode->i_sb, pos, buf, fillsize);
126 if (ret < 0) {
127 SetPageError(page);
128 fillsize = 0;
129 ret = -EIO;
130 }
131 }
132
133 if (fillsize < PAGE_SIZE)
134 memset(buf + fillsize, 0, PAGE_SIZE - fillsize);
135 if (ret == 0)
136 SetPageUptodate(page);
137
138 flush_dcache_page(page);
139 kunmap(page);
140 unlock_page(page);
141 return ret;
142}
143
144static const struct address_space_operations romfs_aops = {
145 .readpage = romfs_readpage
146};
147
148
149
150
151static int romfs_readdir(struct file *file, struct dir_context *ctx)
152{
153 struct inode *i = file_inode(file);
154 struct romfs_inode ri;
155 unsigned long offset, maxoff;
156 int j, ino, nextfh;
157 char fsname[ROMFS_MAXFN];
158 int ret;
159
160 maxoff = romfs_maxsize(i->i_sb);
161
162 offset = ctx->pos;
163 if (!offset) {
164 offset = i->i_ino & ROMFH_MASK;
165 ret = romfs_dev_read(i->i_sb, offset, &ri, ROMFH_SIZE);
166 if (ret < 0)
167 goto out;
168 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
169 }
170
171
172 for (;;) {
173 if (!offset || offset >= maxoff) {
174 offset = maxoff;
175 ctx->pos = offset;
176 goto out;
177 }
178 ctx->pos = offset;
179
180
181 ret = romfs_dev_read(i->i_sb, offset, &ri, ROMFH_SIZE);
182 if (ret < 0)
183 goto out;
184
185 j = romfs_dev_strnlen(i->i_sb, offset + ROMFH_SIZE,
186 sizeof(fsname) - 1);
187 if (j < 0)
188 goto out;
189
190 ret = romfs_dev_read(i->i_sb, offset + ROMFH_SIZE, fsname, j);
191 if (ret < 0)
192 goto out;
193 fsname[j] = '\0';
194
195 ino = offset;
196 nextfh = be32_to_cpu(ri.next);
197 if ((nextfh & ROMFH_TYPE) == ROMFH_HRD)
198 ino = be32_to_cpu(ri.spec);
199 if (!dir_emit(ctx, fsname, j, ino,
200 romfs_dtype_table[nextfh & ROMFH_TYPE]))
201 goto out;
202
203 offset = nextfh & ROMFH_MASK;
204 }
205out:
206 return 0;
207}
208
209
210
211
212static struct dentry *romfs_lookup(struct inode *dir, struct dentry *dentry,
213 unsigned int flags)
214{
215 unsigned long offset, maxoff;
216 struct inode *inode;
217 struct romfs_inode ri;
218 const char *name;
219 int len, ret;
220
221 offset = dir->i_ino & ROMFH_MASK;
222 ret = romfs_dev_read(dir->i_sb, offset, &ri, ROMFH_SIZE);
223 if (ret < 0)
224 goto error;
225
226
227
228 maxoff = romfs_maxsize(dir->i_sb);
229 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
230
231 name = dentry->d_name.name;
232 len = dentry->d_name.len;
233
234 for (;;) {
235 if (!offset || offset >= maxoff)
236 goto out0;
237
238 ret = romfs_dev_read(dir->i_sb, offset, &ri, sizeof(ri));
239 if (ret < 0)
240 goto error;
241
242
243 ret = romfs_dev_strcmp(dir->i_sb, offset + ROMFH_SIZE, name,
244 len);
245 if (ret < 0)
246 goto error;
247 if (ret == 1)
248 break;
249
250
251 offset = be32_to_cpu(ri.next) & ROMFH_MASK;
252 }
253
254
255 if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD)
256 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
257
258 inode = romfs_iget(dir->i_sb, offset);
259 if (IS_ERR(inode)) {
260 ret = PTR_ERR(inode);
261 goto error;
262 }
263 goto outi;
264
265
266
267
268
269
270
271
272
273out0:
274 inode = NULL;
275outi:
276 d_add(dentry, inode);
277 ret = 0;
278error:
279 return ERR_PTR(ret);
280}
281
282static const struct file_operations romfs_dir_operations = {
283 .read = generic_read_dir,
284 .iterate_shared = romfs_readdir,
285 .llseek = generic_file_llseek,
286};
287
288static const struct inode_operations romfs_dir_inode_operations = {
289 .lookup = romfs_lookup,
290};
291
292
293
294
295
296static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)
297{
298 struct romfs_inode_info *inode;
299 struct romfs_inode ri;
300 struct inode *i;
301 unsigned long nlen;
302 unsigned nextfh;
303 int ret;
304 umode_t mode;
305
306
307
308 for (;;) {
309 ret = romfs_dev_read(sb, pos, &ri, sizeof(ri));
310 if (ret < 0)
311 goto error;
312
313
314
315 nextfh = be32_to_cpu(ri.next);
316 if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)
317 break;
318
319 pos = be32_to_cpu(ri.spec) & ROMFH_MASK;
320 }
321
322
323 nlen = romfs_dev_strnlen(sb, pos + ROMFH_SIZE, ROMFS_MAXFN);
324 if (IS_ERR_VALUE(nlen))
325 goto eio;
326
327
328 i = iget_locked(sb, pos);
329 if (!i)
330 return ERR_PTR(-ENOMEM);
331
332 if (!(i->i_state & I_NEW))
333 return i;
334
335
336 inode = ROMFS_I(i);
337 inode->i_metasize = (ROMFH_SIZE + nlen + 1 + ROMFH_PAD) & ROMFH_MASK;
338 inode->i_dataoffset = pos + inode->i_metasize;
339
340 set_nlink(i, 1);
341 i->i_size = be32_to_cpu(ri.size);
342 i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0;
343 i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0;
344
345
346 mode = romfs_modemap[nextfh & ROMFH_TYPE];
347
348 switch (nextfh & ROMFH_TYPE) {
349 case ROMFH_DIR:
350 i->i_size = ROMFS_I(i)->i_metasize;
351 i->i_op = &romfs_dir_inode_operations;
352 i->i_fop = &romfs_dir_operations;
353 if (nextfh & ROMFH_EXEC)
354 mode |= S_IXUGO;
355 break;
356 case ROMFH_REG:
357 i->i_fop = &romfs_ro_fops;
358 i->i_data.a_ops = &romfs_aops;
359 if (nextfh & ROMFH_EXEC)
360 mode |= S_IXUGO;
361 break;
362 case ROMFH_SYM:
363 i->i_op = &page_symlink_inode_operations;
364 inode_nohighmem(i);
365 i->i_data.a_ops = &romfs_aops;
366 mode |= S_IRWXUGO;
367 break;
368 default:
369
370 nextfh = be32_to_cpu(ri.spec);
371 init_special_inode(i, mode, MKDEV(nextfh >> 16,
372 nextfh & 0xffff));
373 break;
374 }
375
376 i->i_mode = mode;
377
378 unlock_new_inode(i);
379 return i;
380
381eio:
382 ret = -EIO;
383error:
384 pr_err("read error for inode 0x%lx\n", pos);
385 return ERR_PTR(ret);
386}
387
388
389
390
391static struct inode *romfs_alloc_inode(struct super_block *sb)
392{
393 struct romfs_inode_info *inode;
394
395 inode = kmem_cache_alloc(romfs_inode_cachep, GFP_KERNEL);
396 return inode ? &inode->vfs_inode : NULL;
397}
398
399
400
401
402static void romfs_i_callback(struct rcu_head *head)
403{
404 struct inode *inode = container_of(head, struct inode, i_rcu);
405
406 kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode));
407}
408
409static void romfs_destroy_inode(struct inode *inode)
410{
411 call_rcu(&inode->i_rcu, romfs_i_callback);
412}
413
414
415
416
417static int romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
418{
419 struct super_block *sb = dentry->d_sb;
420 u64 id = 0;
421
422
423
424
425
426
427
428
429
430
431
432 if (sb->s_bdev)
433 id = huge_encode_dev(sb->s_bdev->bd_dev);
434 else if (sb->s_dev)
435 id = huge_encode_dev(sb->s_dev);
436
437 buf->f_type = ROMFS_MAGIC;
438 buf->f_namelen = ROMFS_MAXFN;
439 buf->f_bsize = ROMBSIZE;
440 buf->f_bfree = buf->f_bavail = buf->f_ffree;
441 buf->f_blocks =
442 (romfs_maxsize(dentry->d_sb) + ROMBSIZE - 1) >> ROMBSBITS;
443 buf->f_fsid.val[0] = (u32)id;
444 buf->f_fsid.val[1] = (u32)(id >> 32);
445 return 0;
446}
447
448
449
450
451static int romfs_remount(struct super_block *sb, int *flags, char *data)
452{
453 sync_filesystem(sb);
454 *flags |= SB_RDONLY;
455 return 0;
456}
457
458static const struct super_operations romfs_super_ops = {
459 .alloc_inode = romfs_alloc_inode,
460 .destroy_inode = romfs_destroy_inode,
461 .statfs = romfs_statfs,
462 .remount_fs = romfs_remount,
463};
464
465
466
467
468static __u32 romfs_checksum(const void *data, int size)
469{
470 const __be32 *ptr = data;
471 __u32 sum;
472
473 sum = 0;
474 size >>= 2;
475 while (size > 0) {
476 sum += be32_to_cpu(*ptr++);
477 size--;
478 }
479 return sum;
480}
481
482
483
484
485static int romfs_fill_super(struct super_block *sb, void *data, int silent)
486{
487 struct romfs_super_block *rsb;
488 struct inode *root;
489 unsigned long pos, img_size;
490 const char *storage;
491 size_t len;
492 int ret;
493
494#ifdef CONFIG_BLOCK
495 if (!sb->s_mtd) {
496 sb_set_blocksize(sb, ROMBSIZE);
497 } else {
498 sb->s_blocksize = ROMBSIZE;
499 sb->s_blocksize_bits = blksize_bits(ROMBSIZE);
500 }
501#endif
502
503 sb->s_maxbytes = 0xFFFFFFFF;
504 sb->s_magic = ROMFS_MAGIC;
505 sb->s_flags |= SB_RDONLY | SB_NOATIME;
506 sb->s_op = &romfs_super_ops;
507
508#ifdef CONFIG_ROMFS_ON_MTD
509
510 if (sb->s_mtd)
511 sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, sb->s_mtd->index);
512#endif
513
514 rsb = kmalloc(512, GFP_KERNEL);
515 if (!rsb)
516 return -ENOMEM;
517
518 sb->s_fs_info = (void *) 512;
519 ret = romfs_dev_read(sb, 0, rsb, 512);
520 if (ret < 0)
521 goto error_rsb;
522
523 img_size = be32_to_cpu(rsb->size);
524
525 if (sb->s_mtd && img_size > sb->s_mtd->size)
526 goto error_rsb_inval;
527
528 sb->s_fs_info = (void *) img_size;
529
530 if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1 ||
531 img_size < ROMFH_SIZE) {
532 if (!silent)
533 pr_warn("VFS: Can't find a romfs filesystem on dev %s.\n",
534 sb->s_id);
535 goto error_rsb_inval;
536 }
537
538 if (romfs_checksum(rsb, min_t(size_t, img_size, 512))) {
539 pr_err("bad initial checksum on dev %s.\n", sb->s_id);
540 goto error_rsb_inval;
541 }
542
543 storage = sb->s_mtd ? "MTD" : "the block layer";
544
545 len = strnlen(rsb->name, ROMFS_MAXFN);
546 if (!silent)
547 pr_notice("Mounting image '%*.*s' through %s\n",
548 (unsigned) len, (unsigned) len, rsb->name, storage);
549
550 kfree(rsb);
551 rsb = NULL;
552
553
554 pos = (ROMFH_SIZE + len + 1 + ROMFH_PAD) & ROMFH_MASK;
555
556 root = romfs_iget(sb, pos);
557 if (IS_ERR(root))
558 return PTR_ERR(root);
559
560 sb->s_root = d_make_root(root);
561 if (!sb->s_root)
562 return -ENOMEM;
563
564 return 0;
565
566error_rsb_inval:
567 ret = -EINVAL;
568error_rsb:
569 kfree(rsb);
570 return ret;
571}
572
573
574
575
576static struct dentry *romfs_mount(struct file_system_type *fs_type,
577 int flags, const char *dev_name,
578 void *data)
579{
580 struct dentry *ret = ERR_PTR(-EINVAL);
581
582#ifdef CONFIG_ROMFS_ON_MTD
583 ret = mount_mtd(fs_type, flags, dev_name, data, romfs_fill_super);
584#endif
585#ifdef CONFIG_ROMFS_ON_BLOCK
586 if (ret == ERR_PTR(-EINVAL))
587 ret = mount_bdev(fs_type, flags, dev_name, data,
588 romfs_fill_super);
589#endif
590 return ret;
591}
592
593
594
595
596static void romfs_kill_sb(struct super_block *sb)
597{
598#ifdef CONFIG_ROMFS_ON_MTD
599 if (sb->s_mtd) {
600 kill_mtd_super(sb);
601 return;
602 }
603#endif
604#ifdef CONFIG_ROMFS_ON_BLOCK
605 if (sb->s_bdev) {
606 kill_block_super(sb);
607 return;
608 }
609#endif
610}
611
612static struct file_system_type romfs_fs_type = {
613 .owner = THIS_MODULE,
614 .name = "romfs",
615 .mount = romfs_mount,
616 .kill_sb = romfs_kill_sb,
617 .fs_flags = FS_REQUIRES_DEV,
618};
619MODULE_ALIAS_FS("romfs");
620
621
622
623
624static void romfs_i_init_once(void *_inode)
625{
626 struct romfs_inode_info *inode = _inode;
627
628 inode_init_once(&inode->vfs_inode);
629}
630
631
632
633
634static int __init init_romfs_fs(void)
635{
636 int ret;
637
638 pr_info("ROMFS MTD (C) 2007 Red Hat, Inc.\n");
639
640 romfs_inode_cachep =
641 kmem_cache_create("romfs_i",
642 sizeof(struct romfs_inode_info), 0,
643 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD |
644 SLAB_ACCOUNT, romfs_i_init_once);
645
646 if (!romfs_inode_cachep) {
647 pr_err("Failed to initialise inode cache\n");
648 return -ENOMEM;
649 }
650 ret = register_filesystem(&romfs_fs_type);
651 if (ret) {
652 pr_err("Failed to register filesystem\n");
653 goto error_register;
654 }
655 return 0;
656
657error_register:
658 kmem_cache_destroy(romfs_inode_cachep);
659 return ret;
660}
661
662
663
664
665static void __exit exit_romfs_fs(void)
666{
667 unregister_filesystem(&romfs_fs_type);
668
669
670
671
672 rcu_barrier();
673 kmem_cache_destroy(romfs_inode_cachep);
674}
675
676module_init(init_romfs_fs);
677module_exit(exit_romfs_fs);
678
679MODULE_DESCRIPTION("Direct-MTD Capable RomFS");
680MODULE_AUTHOR("Red Hat, Inc.");
681MODULE_LICENSE("GPL");
682