source: MondoRescue/trunk/mindi-busybox/e2fsprogs/ext2fs/openfs.c@ 904

Last change on this file since 904 was 821, checked in by Bruno Cornec, 18 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)
File size: 8.7 KB
Line 
1/*
2 * openfs.c --- open an ext2 filesystem
3 *
4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
9 * %End-Header%
10 */
11
12#include <stdio.h>
13#include <string.h>
14#if HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17#include <fcntl.h>
18#include <time.h>
19#if HAVE_SYS_STAT_H
20#include <sys/stat.h>
21#endif
22#if HAVE_SYS_TYPES_H
23#include <sys/types.h>
24#endif
25
26#include "ext2_fs.h"
27
28
29#include "ext2fs.h"
30#include "e2image.h"
31
32blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
33{
34 int bg;
35 int has_super = 0;
36 int ret_blk;
37
38 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
39 (i < fs->super->s_first_meta_bg))
40 return (group_block + i + 1);
41
42 bg = (fs->blocksize / sizeof (struct ext2_group_desc)) * i;
43 if (ext2fs_bg_has_super(fs, bg))
44 has_super = 1;
45 ret_blk = (fs->super->s_first_data_block + has_super +
46 (bg * fs->super->s_blocks_per_group));
47 /*
48 * If group_block is not the normal value, we're trying to use
49 * the backup group descriptors and superblock --- so use the
50 * alternate location of the second block group in the
51 * metablock group. Ideally we should be testing each bg
52 * descriptor block individually for correctness, but we don't
53 * have the infrastructure in place to do that.
54 */
55 if (group_block != fs->super->s_first_data_block &&
56 ((ret_blk + fs->super->s_blocks_per_group) <
57 fs->super->s_blocks_count))
58 ret_blk += fs->super->s_blocks_per_group;
59 return ret_blk;
60}
61
62errcode_t ext2fs_open(const char *name, int flags, int superblock,
63 unsigned int block_size, io_manager manager,
64 ext2_filsys *ret_fs)
65{
66 return ext2fs_open2(name, 0, flags, superblock, block_size,
67 manager, ret_fs);
68}
69
70/*
71 * Note: if superblock is non-zero, block-size must also be non-zero.
72 * Superblock and block_size can be zero to use the default size.
73 *
74 * Valid flags for ext2fs_open()
75 *
76 * EXT2_FLAG_RW - Open the filesystem for read/write.
77 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
78 * features aren't supported.
79 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
80 */
81errcode_t ext2fs_open2(const char *name, const char *io_options,
82 int flags, int superblock,
83 unsigned int block_size, io_manager manager,
84 ext2_filsys *ret_fs)
85{
86 ext2_filsys fs;
87 errcode_t retval;
88 unsigned long i;
89 int groups_per_block, blocks_per_group;
90 blk_t group_block, blk;
91 char *dest, *cp;
92#if BB_BIG_ENDIAN
93 int j;
94 struct ext2_group_desc *gdp;
95#endif
96
97 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
98
99 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
100 if (retval)
101 return retval;
102
103 memset(fs, 0, sizeof(struct struct_ext2_filsys));
104 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
105 fs->flags = flags;
106 fs->umask = 022;
107 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
108 if (retval)
109 goto cleanup;
110 strcpy(fs->device_name, name);
111 cp = strchr(fs->device_name, '?');
112 if (!io_options && cp) {
113 *cp++ = 0;
114 io_options = cp;
115 }
116
117 retval = manager->open(fs->device_name,
118 (flags & EXT2_FLAG_RW) ? IO_FLAG_RW : 0,
119 &fs->io);
120 if (retval)
121 goto cleanup;
122 if (io_options &&
123 (retval = io_channel_set_options(fs->io, io_options)))
124 goto cleanup;
125 fs->image_io = fs->io;
126 fs->io->app_data = fs;
127 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->super);
128 if (retval)
129 goto cleanup;
130 if (flags & EXT2_FLAG_IMAGE_FILE) {
131 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
132 &fs->image_header);
133 if (retval)
134 goto cleanup;
135 retval = io_channel_read_blk(fs->io, 0,
136 -(int)sizeof(struct ext2_image_hdr),
137 fs->image_header);
138 if (retval)
139 goto cleanup;
140 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
141 return EXT2_ET_MAGIC_E2IMAGE;
142 superblock = 1;
143 block_size = fs->image_header->fs_blocksize;
144 }
145
146 /*
147 * If the user specifies a specific block # for the
148 * superblock, then he/she must also specify the block size!
149 * Otherwise, read the master superblock located at offset
150 * SUPERBLOCK_OFFSET from the start of the partition.
151 *
152 * Note: we only save a backup copy of the superblock if we
153 * are reading the superblock from the primary superblock location.
154 */
155 if (superblock) {
156 if (!block_size) {
157 retval = EXT2_ET_INVALID_ARGUMENT;
158 goto cleanup;
159 }
160 io_channel_set_blksize(fs->io, block_size);
161 group_block = superblock;
162 fs->orig_super = 0;
163 } else {
164 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
165 superblock = 1;
166 group_block = 0;
167 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
168 if (retval)
169 goto cleanup;
170 }
171 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
172 fs->super);
173 if (retval)
174 goto cleanup;
175 if (fs->orig_super)
176 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
177
178#if BB_BIG_ENDIAN
179 if ((fs->super->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC)) ||
180 (fs->flags & EXT2_FLAG_SWAP_BYTES)) {
181 fs->flags |= EXT2_FLAG_SWAP_BYTES;
182
183 ext2fs_swap_super(fs->super);
184 }
185#endif
186
187 if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
188 retval = EXT2_ET_BAD_MAGIC;
189 goto cleanup;
190 }
191 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
192 retval = EXT2_ET_REV_TOO_HIGH;
193 goto cleanup;
194 }
195
196 /*
197 * Check for feature set incompatibility
198 */
199 if (!(flags & EXT2_FLAG_FORCE)) {
200 if (fs->super->s_feature_incompat &
201 ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
202 retval = EXT2_ET_UNSUPP_FEATURE;
203 goto cleanup;
204 }
205 if ((flags & EXT2_FLAG_RW) &&
206 (fs->super->s_feature_ro_compat &
207 ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
208 retval = EXT2_ET_RO_UNSUPP_FEATURE;
209 goto cleanup;
210 }
211 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
212 (fs->super->s_feature_incompat &
213 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
214 retval = EXT2_ET_UNSUPP_FEATURE;
215 goto cleanup;
216 }
217 }
218
219 fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
220 if (fs->blocksize == 0) {
221 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
222 goto cleanup;
223 }
224 fs->fragsize = EXT2_FRAG_SIZE(fs->super);
225 fs->inode_blocks_per_group = ((fs->super->s_inodes_per_group *
226 EXT2_INODE_SIZE(fs->super) +
227 EXT2_BLOCK_SIZE(fs->super) - 1) /
228 EXT2_BLOCK_SIZE(fs->super));
229 if (block_size) {
230 if (block_size != fs->blocksize) {
231 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
232 goto cleanup;
233 }
234 }
235 /*
236 * Set the blocksize to the filesystem's blocksize.
237 */
238 io_channel_set_blksize(fs->io, fs->blocksize);
239
240 /*
241 * If this is an external journal device, don't try to read
242 * the group descriptors, because they're not there.
243 */
244 if (fs->super->s_feature_incompat &
245 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
246 fs->group_desc_count = 0;
247 *ret_fs = fs;
248 return 0;
249 }
250
251 /*
252 * Read group descriptors
253 */
254 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
255 if (blocks_per_group == 0 ||
256 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
257 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super)) {
258 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
259 goto cleanup;
260 }
261 fs->group_desc_count = (fs->super->s_blocks_count -
262 fs->super->s_first_data_block +
263 blocks_per_group - 1) / blocks_per_group;
264 fs->desc_blocks = (fs->group_desc_count +
265 EXT2_DESC_PER_BLOCK(fs->super) - 1)
266 / EXT2_DESC_PER_BLOCK(fs->super);
267 retval = ext2fs_get_mem(fs->desc_blocks * fs->blocksize,
268 &fs->group_desc);
269 if (retval)
270 goto cleanup;
271 if (!group_block)
272 group_block = fs->super->s_first_data_block;
273 dest = (char *) fs->group_desc;
274 groups_per_block = fs->blocksize / sizeof(struct ext2_group_desc);
275 for (i=0 ; i < fs->desc_blocks; i++) {
276 blk = ext2fs_descriptor_block_loc(fs, group_block, i);
277 retval = io_channel_read_blk(fs->io, blk, 1, dest);
278 if (retval)
279 goto cleanup;
280#if BB_BIG_ENDIAN
281 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
282 gdp = (struct ext2_group_desc *) dest;
283 for (j=0; j < groups_per_block; j++)
284 ext2fs_swap_group_desc(gdp++);
285 }
286#endif
287 dest += fs->blocksize;
288 }
289
290 *ret_fs = fs;
291 return 0;
292cleanup:
293 ext2fs_free(fs);
294 return retval;
295}
296
297/*
298 * Set/get the filesystem data I/O channel.
299 *
300 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
301 */
302errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
303{
304 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
305 return EXT2_ET_NOT_IMAGE_FILE;
306 if (old_io) {
307 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
308 }
309 return 0;
310}
311
312errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
313{
314 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
315 return EXT2_ET_NOT_IMAGE_FILE;
316 fs->io = new_io ? new_io : fs->image_io;
317 return 0;
318}
319
320errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
321{
322 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
323 return EXT2_ET_NOT_IMAGE_FILE;
324 fs->io = fs->image_io = new_io;
325 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
326 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
327 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
328 return 0;
329}
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