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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 = NULL;
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 break;
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
249 if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD)
250 offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
251 inode = romfs_iget(dir->i_sb, offset);
252 break;
253 }
254
255
256 offset = be32_to_cpu(ri.next) & ROMFH_MASK;
257 }
258
259 return d_splice_alias(inode, dentry);
260error:
261 return ERR_PTR(ret);
262}
263
264static const struct file_operations romfs_dir_operations = {
265 .read = generic_read_dir,
266 .iterate_shared = romfs_readdir,
267 .llseek = generic_file_llseek,
268};
269
270static const struct inode_operations romfs_dir_inode_operations = {
271 .lookup = romfs_lookup,
272};
273
274
275
276
277
278static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)
279{
280 struct romfs_inode_info *inode;
281 struct romfs_inode ri;
282 struct inode *i;
283 unsigned long nlen;
284 unsigned nextfh;
285 int ret;
286 umode_t mode;
287
288
289
290 for (;;) {
291 ret = romfs_dev_read(sb, pos, &ri, sizeof(ri));
292 if (ret < 0)
293 goto error;
294
295
296
297 nextfh = be32_to_cpu(ri.next);
298 if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)
299 break;
300
301 pos = be32_to_cpu(ri.spec) & ROMFH_MASK;
302 }
303
304
305 nlen = romfs_dev_strnlen(sb, pos + ROMFH_SIZE, ROMFS_MAXFN);
306 if (IS_ERR_VALUE(nlen))
307 goto eio;
308
309
310 i = iget_locked(sb, pos);
311 if (!i)
312 return ERR_PTR(-ENOMEM);
313
314 if (!(i->i_state & I_NEW))
315 return i;
316
317
318 inode = ROMFS_I(i);
319 inode->i_metasize = (ROMFH_SIZE + nlen + 1 + ROMFH_PAD) & ROMFH_MASK;
320 inode->i_dataoffset = pos + inode->i_metasize;
321
322 set_nlink(i, 1);
323 i->i_size = be32_to_cpu(ri.size);
324 i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0;
325 i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0;
326
327
328 mode = romfs_modemap[nextfh & ROMFH_TYPE];
329
330 switch (nextfh & ROMFH_TYPE) {
331 case ROMFH_DIR:
332 i->i_size = ROMFS_I(i)->i_metasize;
333 i->i_op = &romfs_dir_inode_operations;
334 i->i_fop = &romfs_dir_operations;
335 if (nextfh & ROMFH_EXEC)
336 mode |= S_IXUGO;
337 break;
338 case ROMFH_REG:
339 i->i_fop = &romfs_ro_fops;
340 i->i_data.a_ops = &romfs_aops;
341 if (nextfh & ROMFH_EXEC)
342 mode |= S_IXUGO;
343 break;
344 case ROMFH_SYM:
345 i->i_op = &page_symlink_inode_operations;
346 inode_nohighmem(i);
347 i->i_data.a_ops = &romfs_aops;
348 mode |= S_IRWXUGO;
349 break;
350 default:
351
352 nextfh = be32_to_cpu(ri.spec);
353 init_special_inode(i, mode, MKDEV(nextfh >> 16,
354 nextfh & 0xffff));
355 break;
356 }
357
358 i->i_mode = mode;
359
360 unlock_new_inode(i);
361 return i;
362
363eio:
364 ret = -EIO;
365error:
366 pr_err("read error for inode 0x%lx\n", pos);
367 return ERR_PTR(ret);
368}
369
370
371
372
373static struct inode *romfs_alloc_inode(struct super_block *sb)
374{
375 struct romfs_inode_info *inode;
376
377 inode = kmem_cache_alloc(romfs_inode_cachep, GFP_KERNEL);
378 return inode ? &inode->vfs_inode : NULL;
379}
380
381
382
383
384static void romfs_free_inode(struct inode *inode)
385{
386 kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode));
387}
388
389
390
391
392static int romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
393{
394 struct super_block *sb = dentry->d_sb;
395 u64 id = 0;
396
397
398
399
400
401
402
403
404
405
406
407 if (sb->s_bdev)
408 id = huge_encode_dev(sb->s_bdev->bd_dev);
409 else if (sb->s_dev)
410 id = huge_encode_dev(sb->s_dev);
411
412 buf->f_type = ROMFS_MAGIC;
413 buf->f_namelen = ROMFS_MAXFN;
414 buf->f_bsize = ROMBSIZE;
415 buf->f_bfree = buf->f_bavail = buf->f_ffree;
416 buf->f_blocks =
417 (romfs_maxsize(dentry->d_sb) + ROMBSIZE - 1) >> ROMBSBITS;
418 buf->f_fsid.val[0] = (u32)id;
419 buf->f_fsid.val[1] = (u32)(id >> 32);
420 return 0;
421}
422
423
424
425
426static int romfs_remount(struct super_block *sb, int *flags, char *data)
427{
428 sync_filesystem(sb);
429 *flags |= SB_RDONLY;
430 return 0;
431}
432
433static const struct super_operations romfs_super_ops = {
434 .alloc_inode = romfs_alloc_inode,
435 .free_inode = romfs_free_inode,
436 .statfs = romfs_statfs,
437 .remount_fs = romfs_remount,
438};
439
440
441
442
443static __u32 romfs_checksum(const void *data, int size)
444{
445 const __be32 *ptr = data;
446 __u32 sum;
447
448 sum = 0;
449 size >>= 2;
450 while (size > 0) {
451 sum += be32_to_cpu(*ptr++);
452 size--;
453 }
454 return sum;
455}
456
457
458
459
460static int romfs_fill_super(struct super_block *sb, void *data, int silent)
461{
462 struct romfs_super_block *rsb;
463 struct inode *root;
464 unsigned long pos, img_size;
465 const char *storage;
466 size_t len;
467 int ret;
468
469#ifdef CONFIG_BLOCK
470 if (!sb->s_mtd) {
471 sb_set_blocksize(sb, ROMBSIZE);
472 } else {
473 sb->s_blocksize = ROMBSIZE;
474 sb->s_blocksize_bits = blksize_bits(ROMBSIZE);
475 }
476#endif
477
478 sb->s_maxbytes = 0xFFFFFFFF;
479 sb->s_magic = ROMFS_MAGIC;
480 sb->s_flags |= SB_RDONLY | SB_NOATIME;
481 sb->s_op = &romfs_super_ops;
482
483#ifdef CONFIG_ROMFS_ON_MTD
484
485 if (sb->s_mtd)
486 sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, sb->s_mtd->index);
487#endif
488
489 rsb = kmalloc(512, GFP_KERNEL);
490 if (!rsb)
491 return -ENOMEM;
492
493 sb->s_fs_info = (void *) 512;
494 ret = romfs_dev_read(sb, 0, rsb, 512);
495 if (ret < 0)
496 goto error_rsb;
497
498 img_size = be32_to_cpu(rsb->size);
499
500 if (sb->s_mtd && img_size > sb->s_mtd->size)
501 goto error_rsb_inval;
502
503 sb->s_fs_info = (void *) img_size;
504
505 if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1 ||
506 img_size < ROMFH_SIZE) {
507 if (!silent)
508 pr_warn("VFS: Can't find a romfs filesystem on dev %s.\n",
509 sb->s_id);
510 goto error_rsb_inval;
511 }
512
513 if (romfs_checksum(rsb, min_t(size_t, img_size, 512))) {
514 pr_err("bad initial checksum on dev %s.\n", sb->s_id);
515 goto error_rsb_inval;
516 }
517
518 storage = sb->s_mtd ? "MTD" : "the block layer";
519
520 len = strnlen(rsb->name, ROMFS_MAXFN);
521 if (!silent)
522 pr_notice("Mounting image '%*.*s' through %s\n",
523 (unsigned) len, (unsigned) len, rsb->name, storage);
524
525 kfree(rsb);
526 rsb = NULL;
527
528
529 pos = (ROMFH_SIZE + len + 1 + ROMFH_PAD) & ROMFH_MASK;
530
531 root = romfs_iget(sb, pos);
532 if (IS_ERR(root))
533 return PTR_ERR(root);
534
535 sb->s_root = d_make_root(root);
536 if (!sb->s_root)
537 return -ENOMEM;
538
539 return 0;
540
541error_rsb_inval:
542 ret = -EINVAL;
543error_rsb:
544 kfree(rsb);
545 return ret;
546}
547
548
549
550
551static struct dentry *romfs_mount(struct file_system_type *fs_type,
552 int flags, const char *dev_name,
553 void *data)
554{
555 struct dentry *ret = ERR_PTR(-EINVAL);
556
557#ifdef CONFIG_ROMFS_ON_MTD
558 ret = mount_mtd(fs_type, flags, dev_name, data, romfs_fill_super);
559#endif
560#ifdef CONFIG_ROMFS_ON_BLOCK
561 if (ret == ERR_PTR(-EINVAL))
562 ret = mount_bdev(fs_type, flags, dev_name, data,
563 romfs_fill_super);
564#endif
565 return ret;
566}
567
568
569
570
571static void romfs_kill_sb(struct super_block *sb)
572{
573#ifdef CONFIG_ROMFS_ON_MTD
574 if (sb->s_mtd) {
575 kill_mtd_super(sb);
576 return;
577 }
578#endif
579#ifdef CONFIG_ROMFS_ON_BLOCK
580 if (sb->s_bdev) {
581 kill_block_super(sb);
582 return;
583 }
584#endif
585}
586
587static struct file_system_type romfs_fs_type = {
588 .owner = THIS_MODULE,
589 .name = "romfs",
590 .mount = romfs_mount,
591 .kill_sb = romfs_kill_sb,
592 .fs_flags = FS_REQUIRES_DEV,
593};
594MODULE_ALIAS_FS("romfs");
595
596
597
598
599static void romfs_i_init_once(void *_inode)
600{
601 struct romfs_inode_info *inode = _inode;
602
603 inode_init_once(&inode->vfs_inode);
604}
605
606
607
608
609static int __init init_romfs_fs(void)
610{
611 int ret;
612
613 pr_info("ROMFS MTD (C) 2007 Red Hat, Inc.\n");
614
615 romfs_inode_cachep =
616 kmem_cache_create("romfs_i",
617 sizeof(struct romfs_inode_info), 0,
618 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD |
619 SLAB_ACCOUNT, romfs_i_init_once);
620
621 if (!romfs_inode_cachep) {
622 pr_err("Failed to initialise inode cache\n");
623 return -ENOMEM;
624 }
625 ret = register_filesystem(&romfs_fs_type);
626 if (ret) {
627 pr_err("Failed to register filesystem\n");
628 goto error_register;
629 }
630 return 0;
631
632error_register:
633 kmem_cache_destroy(romfs_inode_cachep);
634 return ret;
635}
636
637
638
639
640static void __exit exit_romfs_fs(void)
641{
642 unregister_filesystem(&romfs_fs_type);
643
644
645
646
647 rcu_barrier();
648 kmem_cache_destroy(romfs_inode_cachep);
649}
650
651module_init(init_romfs_fs);
652module_exit(exit_romfs_fs);
653
654MODULE_DESCRIPTION("Direct-MTD Capable RomFS");
655MODULE_AUTHOR("Red Hat, Inc.");
656MODULE_LICENSE("GPL");
657