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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 Library
8  * General Public License, version 2.
9  * %End-Header%
10  */
11 
12 #include "config.h"
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 #ifdef HAVE_SYS_STAT_H
21 #include <sys/stat.h>
22 #endif
23 #ifdef HAVE_SYS_TYPES_H
24 #include <sys/types.h>
25 #endif
26 
27 #include "ext2_fs.h"
28 #include "ext2fs.h"
29 #include "e2image.h"
30 
write_bitmaps(ext2_filsys fs,int do_inode,int do_block)31 static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
32 {
33 	dgrp_t 		i;
34 	unsigned int	j;
35 	int		block_nbytes, inode_nbytes;
36 	unsigned int	nbits;
37 	errcode_t	retval;
38 	char		*block_buf = NULL, *inode_buf = NULL;
39 	int		csum_flag;
40 	blk64_t		blk;
41 	blk64_t		blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
42 	ext2_ino_t	ino_itr = 1;
43 
44 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
45 
46 	if (!(fs->flags & EXT2_FLAG_RW))
47 		return EXT2_ET_RO_FILSYS;
48 
49 	csum_flag = ext2fs_has_group_desc_csum(fs);
50 
51 	inode_nbytes = block_nbytes = 0;
52 	if (do_block) {
53 		block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
54 		retval = io_channel_alloc_buf(fs->io, 0, &block_buf);
55 		if (retval)
56 			goto errout;
57 		memset(block_buf, 0xff, fs->blocksize);
58 	}
59 	if (do_inode) {
60 		inode_nbytes = (size_t)
61 			((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
62 		retval = io_channel_alloc_buf(fs->io, 0, &inode_buf);
63 		if (retval)
64 			goto errout;
65 		memset(inode_buf, 0xff, fs->blocksize);
66 	}
67 
68 	for (i = 0; i < fs->group_desc_count; i++) {
69 		if (!do_block)
70 			goto skip_block_bitmap;
71 
72 		if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT)
73 		    )
74 			goto skip_this_block_bitmap;
75 
76 		retval = ext2fs_get_block_bitmap_range2(fs->block_map,
77 				blk_itr, block_nbytes << 3, block_buf);
78 		if (retval)
79 			goto errout;
80 
81 		if (i == fs->group_desc_count - 1) {
82 			/* Force bitmap padding for the last group */
83 			nbits = EXT2FS_NUM_B2C(fs,
84 				((ext2fs_blocks_count(fs->super)
85 				  - (__u64) fs->super->s_first_data_block)
86 				 % (__u64) EXT2_BLOCKS_PER_GROUP(fs->super)));
87 			if (nbits)
88 				for (j = nbits; j < fs->blocksize * 8; j++)
89 					ext2fs_set_bit(j, block_buf);
90 		}
91 
92 		retval = ext2fs_block_bitmap_csum_set(fs, i, block_buf,
93 						      block_nbytes);
94 		if (retval)
95 			return retval;
96 		ext2fs_group_desc_csum_set(fs, i);
97 
98 		blk = ext2fs_block_bitmap_loc(fs, i);
99 		if (blk) {
100 			retval = io_channel_write_blk64(fs->io, blk, 1,
101 							block_buf);
102 			if (retval) {
103 				retval = EXT2_ET_BLOCK_BITMAP_WRITE;
104 				goto errout;
105 			}
106 		}
107 	skip_this_block_bitmap:
108 		blk_itr += block_nbytes << 3;
109 	skip_block_bitmap:
110 
111 		if (!do_inode)
112 			continue;
113 
114 		if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT)
115 		    )
116 			goto skip_this_inode_bitmap;
117 
118 		retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
119 				ino_itr, inode_nbytes << 3, inode_buf);
120 		if (retval)
121 			goto errout;
122 
123 		retval = ext2fs_inode_bitmap_csum_set(fs, i, inode_buf,
124 						      inode_nbytes);
125 		if (retval)
126 			goto errout;
127 		ext2fs_group_desc_csum_set(fs, i);
128 
129 		blk = ext2fs_inode_bitmap_loc(fs, i);
130 		if (blk) {
131 			retval = io_channel_write_blk64(fs->io, blk, 1,
132 						      inode_buf);
133 			if (retval) {
134 				retval = EXT2_ET_INODE_BITMAP_WRITE;
135 				goto errout;
136 			}
137 		}
138 	skip_this_inode_bitmap:
139 		ino_itr += inode_nbytes << 3;
140 
141 	}
142 	if (do_block) {
143 		fs->flags &= ~EXT2_FLAG_BB_DIRTY;
144 		ext2fs_free_mem(&block_buf);
145 	}
146 	if (do_inode) {
147 		fs->flags &= ~EXT2_FLAG_IB_DIRTY;
148 		ext2fs_free_mem(&inode_buf);
149 	}
150 	return 0;
151 errout:
152 	if (inode_buf)
153 		ext2fs_free_mem(&inode_buf);
154 	if (block_buf)
155 		ext2fs_free_mem(&block_buf);
156 	return retval;
157 }
158 
mark_uninit_bg_group_blocks(ext2_filsys fs)159 static errcode_t mark_uninit_bg_group_blocks(ext2_filsys fs)
160 {
161 	dgrp_t			i;
162 	blk64_t			blk;
163 	ext2fs_block_bitmap	bmap = fs->block_map;
164 
165 	for (i = 0; i < fs->group_desc_count; i++) {
166 		if (!ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT))
167 			continue;
168 
169 		ext2fs_reserve_super_and_bgd(fs, i, bmap);
170 
171 		/*
172 		 * Mark the blocks used for the inode table
173 		 */
174 		blk = ext2fs_inode_table_loc(fs, i);
175 		if (blk)
176 			ext2fs_mark_block_bitmap_range2(bmap, blk,
177 						fs->inode_blocks_per_group);
178 
179 		/*
180 		 * Mark block used for the block bitmap
181 		 */
182 		blk = ext2fs_block_bitmap_loc(fs, i);
183 		if (blk)
184 			ext2fs_mark_block_bitmap2(bmap, blk);
185 
186 		/*
187 		 * Mark block used for the inode bitmap
188 		 */
189 		blk = ext2fs_inode_bitmap_loc(fs, i);
190 		if (blk)
191 			ext2fs_mark_block_bitmap2(bmap, blk);
192 	}
193 	return 0;
194 }
195 
read_bitmaps(ext2_filsys fs,int do_inode,int do_block)196 static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
197 {
198 	dgrp_t i;
199 	char *block_bitmap = 0, *inode_bitmap = 0;
200 	char *buf;
201 	errcode_t retval;
202 	int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
203 	int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
204 	int csum_flag;
205 	unsigned int	cnt;
206 	blk64_t	blk;
207 	blk64_t	blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
208 	blk64_t   blk_cnt;
209 	ext2_ino_t ino_itr = 1;
210 	ext2_ino_t ino_cnt;
211 
212 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
213 
214 	if ((block_nbytes > (int) fs->blocksize) ||
215 	    (inode_nbytes > (int) fs->blocksize))
216 		return EXT2_ET_CORRUPT_SUPERBLOCK;
217 
218 	fs->write_bitmaps = ext2fs_write_bitmaps;
219 
220 	csum_flag = ext2fs_has_group_desc_csum(fs);
221 
222 	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
223 	if (retval)
224 		return retval;
225 	if (do_block) {
226 		if (fs->block_map)
227 			ext2fs_free_block_bitmap(fs->block_map);
228 		strcpy(buf, "block bitmap for ");
229 		strcat(buf, fs->device_name);
230 		retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
231 		if (retval)
232 			goto cleanup;
233 		retval = io_channel_alloc_buf(fs->io, 0, &block_bitmap);
234 		if (retval)
235 			goto cleanup;
236 	} else
237 		block_nbytes = 0;
238 	if (do_inode) {
239 		if (fs->inode_map)
240 			ext2fs_free_inode_bitmap(fs->inode_map);
241 		strcpy(buf, "inode bitmap for ");
242 		strcat(buf, fs->device_name);
243 		retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
244 		if (retval)
245 			goto cleanup;
246 		retval = io_channel_alloc_buf(fs->io, 0, &inode_bitmap);
247 		if (retval)
248 			goto cleanup;
249 	} else
250 		inode_nbytes = 0;
251 	ext2fs_free_mem(&buf);
252 
253 	if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
254 		blk = (fs->image_header->offset_inodemap / fs->blocksize);
255 		ino_cnt = fs->super->s_inodes_count;
256 		while (inode_nbytes > 0) {
257 			retval = io_channel_read_blk64(fs->image_io, blk++,
258 						     1, inode_bitmap);
259 			if (retval)
260 				goto cleanup;
261 			cnt = fs->blocksize << 3;
262 			if (cnt > ino_cnt)
263 				cnt = ino_cnt;
264 			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
265 					       ino_itr, cnt, inode_bitmap);
266 			if (retval)
267 				goto cleanup;
268 			ino_itr += fs->blocksize << 3;
269 			ino_cnt -= fs->blocksize << 3;
270 			inode_nbytes -= fs->blocksize;
271 		}
272 		blk = (fs->image_header->offset_blockmap /
273 		       fs->blocksize);
274 		blk_cnt = EXT2_GROUPS_TO_CLUSTERS(fs->super,
275 						  fs->group_desc_count);
276 		while (block_nbytes > 0) {
277 			retval = io_channel_read_blk64(fs->image_io, blk++,
278 						     1, block_bitmap);
279 			if (retval)
280 				goto cleanup;
281 			cnt = fs->blocksize << 3;
282 			if (cnt > blk_cnt)
283 				cnt = blk_cnt;
284 			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
285 				       blk_itr, cnt, block_bitmap);
286 			if (retval)
287 				goto cleanup;
288 			blk_itr += fs->blocksize << 3;
289 			blk_cnt -= fs->blocksize << 3;
290 			block_nbytes -= fs->blocksize;
291 		}
292 		goto success_cleanup;
293 	}
294 
295 	for (i = 0; i < fs->group_desc_count; i++) {
296 		if (block_bitmap) {
297 			blk = ext2fs_block_bitmap_loc(fs, i);
298 			if (csum_flag &&
299 			    ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
300 			    ext2fs_group_desc_csum_verify(fs, i))
301 				blk = 0;
302 			if (blk) {
303 				retval = io_channel_read_blk64(fs->io, blk,
304 							       1, block_bitmap);
305 				if (retval) {
306 					retval = EXT2_ET_BLOCK_BITMAP_READ;
307 					goto cleanup;
308 				}
309 				/* verify block bitmap checksum */
310 				if (!(fs->flags &
311 				      EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
312 				    !ext2fs_block_bitmap_csum_verify(fs, i,
313 						block_bitmap, block_nbytes)) {
314 					retval =
315 					EXT2_ET_BLOCK_BITMAP_CSUM_INVALID;
316 					goto cleanup;
317 				}
318 			} else
319 				memset(block_bitmap, 0, block_nbytes);
320 			cnt = block_nbytes << 3;
321 			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
322 					       blk_itr, cnt, block_bitmap);
323 			if (retval)
324 				goto cleanup;
325 			blk_itr += block_nbytes << 3;
326 		}
327 		if (inode_bitmap) {
328 			blk = ext2fs_inode_bitmap_loc(fs, i);
329 			if (csum_flag &&
330 			    ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
331 			    ext2fs_group_desc_csum_verify(fs, i))
332 				blk = 0;
333 			if (blk) {
334 				retval = io_channel_read_blk64(fs->io, blk,
335 							       1, inode_bitmap);
336 				if (retval) {
337 					retval = EXT2_ET_INODE_BITMAP_READ;
338 					goto cleanup;
339 				}
340 
341 				/* verify inode bitmap checksum */
342 				if (!(fs->flags &
343 				      EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
344 				    !ext2fs_inode_bitmap_csum_verify(fs, i,
345 						inode_bitmap, inode_nbytes)) {
346 					retval =
347 					EXT2_ET_INODE_BITMAP_CSUM_INVALID;
348 					goto cleanup;
349 				}
350 			} else
351 				memset(inode_bitmap, 0, inode_nbytes);
352 			cnt = inode_nbytes << 3;
353 			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
354 					       ino_itr, cnt, inode_bitmap);
355 			if (retval)
356 				goto cleanup;
357 			ino_itr += inode_nbytes << 3;
358 		}
359 	}
360 
361 	/* Mark group blocks for any BLOCK_UNINIT groups */
362 	if (do_block) {
363 		retval = mark_uninit_bg_group_blocks(fs);
364 		if (retval)
365 			goto cleanup;
366 	}
367 
368 success_cleanup:
369 	if (inode_bitmap)
370 		ext2fs_free_mem(&inode_bitmap);
371 	if (block_bitmap)
372 		ext2fs_free_mem(&block_bitmap);
373 	return 0;
374 
375 cleanup:
376 	if (do_block) {
377 		ext2fs_free_mem(&fs->block_map);
378 		fs->block_map = 0;
379 	}
380 	if (do_inode) {
381 		ext2fs_free_mem(&fs->inode_map);
382 		fs->inode_map = 0;
383 	}
384 	if (inode_bitmap)
385 		ext2fs_free_mem(&inode_bitmap);
386 	if (block_bitmap)
387 		ext2fs_free_mem(&block_bitmap);
388 	if (buf)
389 		ext2fs_free_mem(&buf);
390 	return retval;
391 }
392 
ext2fs_read_inode_bitmap(ext2_filsys fs)393 errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
394 {
395 	return read_bitmaps(fs, 1, 0);
396 }
397 
ext2fs_read_block_bitmap(ext2_filsys fs)398 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
399 {
400 	return read_bitmaps(fs, 0, 1);
401 }
402 
ext2fs_write_inode_bitmap(ext2_filsys fs)403 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
404 {
405 	return write_bitmaps(fs, 1, 0);
406 }
407 
ext2fs_write_block_bitmap(ext2_filsys fs)408 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
409 {
410 	return write_bitmaps(fs, 0, 1);
411 }
412 
ext2fs_read_bitmaps(ext2_filsys fs)413 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
414 {
415 	if (fs->inode_map && fs->block_map)
416 		return 0;
417 
418 	return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
419 }
420 
ext2fs_write_bitmaps(ext2_filsys fs)421 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
422 {
423 	int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
424 	int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
425 
426 	if (!do_inode && !do_block)
427 		return 0;
428 
429 	return write_bitmaps(fs, do_inode, do_block);
430 }
431