source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/ext2fs/rw_bitmaps.c@ 821

Last change on this file since 821 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: 7.3 KB
RevLine 
[821]1/*
2 * rw_bitmaps.c --- routines to read and write the inode and block bitmaps.
3 *
4 * Copyright (C) 1993, 1994, 1994, 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#ifdef HAVE_SYS_STAT_H
20#include <sys/stat.h>
21#endif
22#ifdef HAVE_SYS_TYPES_H
23#include <sys/types.h>
24#endif
25
26#include "ext2_fs.h"
27#include "ext2fs.h"
28#include "e2image.h"
29
30#if defined(__powerpc__) && BB_BIG_ENDIAN
31/*
32 * On the PowerPC, the big-endian variant of the ext2 filesystem
33 * has its bitmaps stored as 32-bit words with bit 0 as the LSB
34 * of each word. Thus a bitmap with only bit 0 set would be, as
35 * a string of bytes, 00 00 00 01 00 ...
36 * To cope with this, we byte-reverse each word of a bitmap if
37 * we have a big-endian filesystem, that is, if we are *not*
38 * byte-swapping other word-sized numbers.
39 */
40#define EXT2_BIG_ENDIAN_BITMAPS
41#endif
42
43#ifdef EXT2_BIG_ENDIAN_BITMAPS
44static void ext2fs_swap_bitmap(ext2_filsys fs, char *bitmap, int nbytes)
45{
46 __u32 *p = (__u32 *) bitmap;
47 int n;
48
49 for (n = nbytes / sizeof(__u32); n > 0; --n, ++p)
50 *p = ext2fs_swab32(*p);
51}
52#endif
53
54errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
55{
56 dgrp_t i;
57 size_t nbytes;
58 errcode_t retval;
59 char * inode_bitmap = fs->inode_map->bitmap;
60 char * bitmap_block = NULL;
61 blk_t blk;
62
63 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
64
65 if (!(fs->flags & EXT2_FLAG_RW))
66 return EXT2_ET_RO_FILSYS;
67 if (!inode_bitmap)
68 return 0;
69 nbytes = (size_t) ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
70
71 retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
72 if (retval)
73 return retval;
74 memset(bitmap_block, 0xff, fs->blocksize);
75 for (i = 0; i < fs->group_desc_count; i++) {
76 memcpy(bitmap_block, inode_bitmap, nbytes);
77 blk = fs->group_desc[i].bg_inode_bitmap;
78 if (blk) {
79#ifdef EXT2_BIG_ENDIAN_BITMAPS
80 if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
81 (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
82 ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
83#endif
84 retval = io_channel_write_blk(fs->io, blk, 1,
85 bitmap_block);
86 if (retval)
87 return EXT2_ET_INODE_BITMAP_WRITE;
88 }
89 inode_bitmap += nbytes;
90 }
91 fs->flags &= ~EXT2_FLAG_IB_DIRTY;
92 ext2fs_free_mem(&bitmap_block);
93 return 0;
94}
95
96errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
97{
98 dgrp_t i;
99 unsigned int j;
100 int nbytes;
101 unsigned int nbits;
102 errcode_t retval;
103 char * block_bitmap = fs->block_map->bitmap;
104 char * bitmap_block = NULL;
105 blk_t blk;
106
107 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
108
109 if (!(fs->flags & EXT2_FLAG_RW))
110 return EXT2_ET_RO_FILSYS;
111 if (!block_bitmap)
112 return 0;
113 nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
114 retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
115 if (retval)
116 return retval;
117 memset(bitmap_block, 0xff, fs->blocksize);
118 for (i = 0; i < fs->group_desc_count; i++) {
119 memcpy(bitmap_block, block_bitmap, nbytes);
120 if (i == fs->group_desc_count - 1) {
121 /* Force bitmap padding for the last group */
122 nbits = ((fs->super->s_blocks_count
123 - fs->super->s_first_data_block)
124 % EXT2_BLOCKS_PER_GROUP(fs->super));
125 if (nbits)
126 for (j = nbits; j < fs->blocksize * 8; j++)
127 ext2fs_set_bit(j, bitmap_block);
128 }
129 blk = fs->group_desc[i].bg_block_bitmap;
130 if (blk) {
131#ifdef EXT2_BIG_ENDIAN_BITMAPS
132 if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
133 (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
134 ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
135#endif
136 retval = io_channel_write_blk(fs->io, blk, 1,
137 bitmap_block);
138 if (retval)
139 return EXT2_ET_BLOCK_BITMAP_WRITE;
140 }
141 block_bitmap += nbytes;
142 }
143 fs->flags &= ~EXT2_FLAG_BB_DIRTY;
144 ext2fs_free_mem(&bitmap_block);
145 return 0;
146}
147
148static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
149{
150 dgrp_t i;
151 char *block_bitmap = 0, *inode_bitmap = 0;
152 char *buf;
153 errcode_t retval;
154 int block_nbytes = (int) EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
155 int inode_nbytes = (int) EXT2_INODES_PER_GROUP(fs->super) / 8;
156 blk_t blk;
157
158 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
159
160 fs->write_bitmaps = ext2fs_write_bitmaps;
161
162 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
163 if (retval)
164 return retval;
165 if (do_block) {
166 ext2fs_free_block_bitmap(fs->block_map);
167 sprintf(buf, "block bitmap for %s", fs->device_name);
168 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
169 if (retval)
170 goto cleanup;
171 block_bitmap = fs->block_map->bitmap;
172 }
173 if (do_inode) {
174 ext2fs_free_inode_bitmap(fs->inode_map);
175 sprintf(buf, "inode bitmap for %s", fs->device_name);
176 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
177 if (retval)
178 goto cleanup;
179 inode_bitmap = fs->inode_map->bitmap;
180 }
181 ext2fs_free_mem(&buf);
182
183 if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
184 if (inode_bitmap) {
185 blk = (fs->image_header->offset_inodemap /
186 fs->blocksize);
187 retval = io_channel_read_blk(fs->image_io, blk,
188 -(inode_nbytes * fs->group_desc_count),
189 inode_bitmap);
190 if (retval)
191 goto cleanup;
192 }
193 if (block_bitmap) {
194 blk = (fs->image_header->offset_blockmap /
195 fs->blocksize);
196 retval = io_channel_read_blk(fs->image_io, blk,
197 -(block_nbytes * fs->group_desc_count),
198 block_bitmap);
199 if (retval)
200 goto cleanup;
201 }
202 return 0;
203 }
204
205 for (i = 0; i < fs->group_desc_count; i++) {
206 if (block_bitmap) {
207 blk = fs->group_desc[i].bg_block_bitmap;
208 if (blk) {
209 retval = io_channel_read_blk(fs->io, blk,
210 -block_nbytes, block_bitmap);
211 if (retval) {
212 retval = EXT2_ET_BLOCK_BITMAP_READ;
213 goto cleanup;
214 }
215#ifdef EXT2_BIG_ENDIAN_BITMAPS
216 if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
217 (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
218 ext2fs_swap_bitmap(fs, block_bitmap, block_nbytes);
219#endif
220 } else
221 memset(block_bitmap, 0, block_nbytes);
222 block_bitmap += block_nbytes;
223 }
224 if (inode_bitmap) {
225 blk = fs->group_desc[i].bg_inode_bitmap;
226 if (blk) {
227 retval = io_channel_read_blk(fs->io, blk,
228 -inode_nbytes, inode_bitmap);
229 if (retval) {
230 retval = EXT2_ET_INODE_BITMAP_READ;
231 goto cleanup;
232 }
233#ifdef EXT2_BIG_ENDIAN_BITMAPS
234 if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
235 (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
236 ext2fs_swap_bitmap(fs, inode_bitmap, inode_nbytes);
237#endif
238 } else
239 memset(inode_bitmap, 0, inode_nbytes);
240 inode_bitmap += inode_nbytes;
241 }
242 }
243 return 0;
244
245cleanup:
246 if (do_block) {
247 ext2fs_free_mem(&fs->block_map);
248 }
249 if (do_inode) {
250 ext2fs_free_mem(&fs->inode_map);
251 }
252 ext2fs_free_mem(&buf);
253 return retval;
254}
255
256errcode_t ext2fs_read_inode_bitmap (ext2_filsys fs)
257{
258 return read_bitmaps(fs, 1, 0);
259}
260
261errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
262{
263 return read_bitmaps(fs, 0, 1);
264}
265
266errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
267{
268
269 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
270
271 if (fs->inode_map && fs->block_map)
272 return 0;
273
274 return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
275}
276
277errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
278{
279 errcode_t retval;
280
281 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
282
283 if (fs->block_map && ext2fs_test_bb_dirty(fs)) {
284 retval = ext2fs_write_block_bitmap(fs);
285 if (retval)
286 return retval;
287 }
288 if (fs->inode_map && ext2fs_test_ib_dirty(fs)) {
289 retval = ext2fs_write_inode_bitmap(fs);
290 if (retval)
291 return retval;
292 }
293 return 0;
294}
295
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