source: MondoRescue/branches/2.2.5/mindi-busybox/e2fsprogs/old_e2fsprogs/ext2fs/openfs.c@ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 16 years ago

Update to busybox 1.7.2
  • Property svn:eol-style set to native
File size: 8.7 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * openfs.c --- open an ext2 filesystem
4 *
5 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the GNU Public
9 * License.
10 * %End-Header%
11 */
12
13#include <stdio.h>
14#include <string.h>
15#if HAVE_UNISTD_H
16#include <unistd.h>
17#endif
18#include <fcntl.h>
19#include <time.h>
20#if HAVE_SYS_STAT_H
21#include <sys/stat.h>
22#endif
23#if HAVE_SYS_TYPES_H
24#include <sys/types.h>
25#endif
26
27#include "ext2_fs.h"
28
29
30#include "ext2fs.h"
31#include "e2image.h"
32
33blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
34{
35 int bg;
36 int has_super = 0;
37 int ret_blk;
38
39 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
40 (i < fs->super->s_first_meta_bg))
41 return (group_block + i + 1);
42
43 bg = (fs->blocksize / sizeof (struct ext2_group_desc)) * i;
44 if (ext2fs_bg_has_super(fs, bg))
45 has_super = 1;
46 ret_blk = (fs->super->s_first_data_block + has_super +
47 (bg * fs->super->s_blocks_per_group));
48 /*
49 * If group_block is not the normal value, we're trying to use
50 * the backup group descriptors and superblock --- so use the
51 * alternate location of the second block group in the
52 * metablock group. Ideally we should be testing each bg
53 * descriptor block individually for correctness, but we don't
54 * have the infrastructure in place to do that.
55 */
56 if (group_block != fs->super->s_first_data_block &&
57 ((ret_blk + fs->super->s_blocks_per_group) <
58 fs->super->s_blocks_count))
59 ret_blk += fs->super->s_blocks_per_group;
60 return ret_blk;
61}
62
63errcode_t ext2fs_open(const char *name, int flags, int superblock,
64 unsigned int block_size, io_manager manager,
65 ext2_filsys *ret_fs)
66{
67 return ext2fs_open2(name, 0, flags, superblock, block_size,
68 manager, ret_fs);
69}
70
71/*
72 * Note: if superblock is non-zero, block-size must also be non-zero.
73 * Superblock and block_size can be zero to use the default size.
74 *
75 * Valid flags for ext2fs_open()
76 *
77 * EXT2_FLAG_RW - Open the filesystem for read/write.
78 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
79 * features aren't supported.
80 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
81 */
82errcode_t ext2fs_open2(const char *name, const char *io_options,
83 int flags, int superblock,
84 unsigned int block_size, io_manager manager,
85 ext2_filsys *ret_fs)
86{
87 ext2_filsys fs;
88 errcode_t retval;
89 unsigned long i;
90 int groups_per_block, blocks_per_group;
91 blk_t group_block, blk;
92 char *dest, *cp;
93#if BB_BIG_ENDIAN
94 int j;
95 struct ext2_group_desc *gdp;
96#endif
97
98 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
99
100 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
101 if (retval)
102 return retval;
103
104 memset(fs, 0, sizeof(struct struct_ext2_filsys));
105 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
106 fs->flags = flags;
107 fs->umask = 022;
108 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
109 if (retval)
110 goto cleanup;
111 strcpy(fs->device_name, name);
112 cp = strchr(fs->device_name, '?');
113 if (!io_options && cp) {
114 *cp++ = 0;
115 io_options = cp;
116 }
117
118 retval = manager->open(fs->device_name,
119 (flags & EXT2_FLAG_RW) ? IO_FLAG_RW : 0,
120 &fs->io);
121 if (retval)
122 goto cleanup;
123 if (io_options &&
124 (retval = io_channel_set_options(fs->io, io_options)))
125 goto cleanup;
126 fs->image_io = fs->io;
127 fs->io->app_data = fs;
128 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->super);
129 if (retval)
130 goto cleanup;
131 if (flags & EXT2_FLAG_IMAGE_FILE) {
132 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
133 &fs->image_header);
134 if (retval)
135 goto cleanup;
136 retval = io_channel_read_blk(fs->io, 0,
137 -(int)sizeof(struct ext2_image_hdr),
138 fs->image_header);
139 if (retval)
140 goto cleanup;
141 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
142 return EXT2_ET_MAGIC_E2IMAGE;
143 superblock = 1;
144 block_size = fs->image_header->fs_blocksize;
145 }
146
147 /*
148 * If the user specifies a specific block # for the
149 * superblock, then he/she must also specify the block size!
150 * Otherwise, read the master superblock located at offset
151 * SUPERBLOCK_OFFSET from the start of the partition.
152 *
153 * Note: we only save a backup copy of the superblock if we
154 * are reading the superblock from the primary superblock location.
155 */
156 if (superblock) {
157 if (!block_size) {
158 retval = EXT2_ET_INVALID_ARGUMENT;
159 goto cleanup;
160 }
161 io_channel_set_blksize(fs->io, block_size);
162 group_block = superblock;
163 fs->orig_super = 0;
164 } else {
165 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
166 superblock = 1;
167 group_block = 0;
168 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
169 if (retval)
170 goto cleanup;
171 }
172 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
173 fs->super);
174 if (retval)
175 goto cleanup;
176 if (fs->orig_super)
177 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
178
179#if BB_BIG_ENDIAN
180 if ((fs->super->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC)) ||
181 (fs->flags & EXT2_FLAG_SWAP_BYTES)) {
182 fs->flags |= EXT2_FLAG_SWAP_BYTES;
183
184 ext2fs_swap_super(fs->super);
185 }
186#endif
187
188 if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
189 retval = EXT2_ET_BAD_MAGIC;
190 goto cleanup;
191 }
192 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
193 retval = EXT2_ET_REV_TOO_HIGH;
194 goto cleanup;
195 }
196
197 /*
198 * Check for feature set incompatibility
199 */
200 if (!(flags & EXT2_FLAG_FORCE)) {
201 if (fs->super->s_feature_incompat &
202 ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
203 retval = EXT2_ET_UNSUPP_FEATURE;
204 goto cleanup;
205 }
206 if ((flags & EXT2_FLAG_RW) &&
207 (fs->super->s_feature_ro_compat &
208 ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
209 retval = EXT2_ET_RO_UNSUPP_FEATURE;
210 goto cleanup;
211 }
212 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
213 (fs->super->s_feature_incompat &
214 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
215 retval = EXT2_ET_UNSUPP_FEATURE;
216 goto cleanup;
217 }
218 }
219
220 fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
221 if (fs->blocksize == 0) {
222 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
223 goto cleanup;
224 }
225 fs->fragsize = EXT2_FRAG_SIZE(fs->super);
226 fs->inode_blocks_per_group = ((fs->super->s_inodes_per_group *
227 EXT2_INODE_SIZE(fs->super) +
228 EXT2_BLOCK_SIZE(fs->super) - 1) /
229 EXT2_BLOCK_SIZE(fs->super));
230 if (block_size) {
231 if (block_size != fs->blocksize) {
232 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
233 goto cleanup;
234 }
235 }
236 /*
237 * Set the blocksize to the filesystem's blocksize.
238 */
239 io_channel_set_blksize(fs->io, fs->blocksize);
240
241 /*
242 * If this is an external journal device, don't try to read
243 * the group descriptors, because they're not there.
244 */
245 if (fs->super->s_feature_incompat &
246 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
247 fs->group_desc_count = 0;
248 *ret_fs = fs;
249 return 0;
250 }
251
252 /*
253 * Read group descriptors
254 */
255 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
256 if (blocks_per_group == 0 ||
257 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
258 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super)) {
259 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
260 goto cleanup;
261 }
262 fs->group_desc_count = (fs->super->s_blocks_count -
263 fs->super->s_first_data_block +
264 blocks_per_group - 1) / blocks_per_group;
265 fs->desc_blocks = (fs->group_desc_count +
266 EXT2_DESC_PER_BLOCK(fs->super) - 1)
267 / EXT2_DESC_PER_BLOCK(fs->super);
268 retval = ext2fs_get_mem(fs->desc_blocks * fs->blocksize,
269 &fs->group_desc);
270 if (retval)
271 goto cleanup;
272 if (!group_block)
273 group_block = fs->super->s_first_data_block;
274 dest = (char *) fs->group_desc;
275 groups_per_block = fs->blocksize / sizeof(struct ext2_group_desc);
276 for (i = 0; i < fs->desc_blocks; i++) {
277 blk = ext2fs_descriptor_block_loc(fs, group_block, i);
278 retval = io_channel_read_blk(fs->io, blk, 1, dest);
279 if (retval)
280 goto cleanup;
281#if BB_BIG_ENDIAN
282 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
283 gdp = (struct ext2_group_desc *) dest;
284 for (j=0; j < groups_per_block; j++)
285 ext2fs_swap_group_desc(gdp++);
286 }
287#endif
288 dest += fs->blocksize;
289 }
290
291 *ret_fs = fs;
292 return 0;
293cleanup:
294 ext2fs_free(fs);
295 return retval;
296}
297
298/*
299 * Set/get the filesystem data I/O channel.
300 *
301 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
302 */
303errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
304{
305 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
306 return EXT2_ET_NOT_IMAGE_FILE;
307 if (old_io) {
308 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
309 }
310 return 0;
311}
312
313errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
314{
315 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
316 return EXT2_ET_NOT_IMAGE_FILE;
317 fs->io = new_io ? new_io : fs->image_io;
318 return 0;
319}
320
321errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
322{
323 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
324 return EXT2_ET_NOT_IMAGE_FILE;
325 fs->io = fs->image_io = new_io;
326 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
327 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
328 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
329 return 0;
330}
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