1/*
2 * bitmaps.c --- routines to read, write, and manipulate the inode and
3 * block bitmaps.
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#include "ext2fs.h"
29
30static errcode_t make_bitmap(__u32 start, __u32 end, __u32 real_end,
31			     const char *descr, char *init_map,
32			     ext2fs_generic_bitmap *ret)
33{
34	ext2fs_generic_bitmap	bitmap;
35	errcode_t		retval;
36	size_t			size;
37
38	retval = ext2fs_get_mem(sizeof(struct ext2fs_struct_generic_bitmap),
39				&bitmap);
40	if (retval)
41		return retval;
42
43	bitmap->magic = EXT2_ET_MAGIC_GENERIC_BITMAP;
44	bitmap->fs = NULL;
45	bitmap->start = start;
46	bitmap->end = end;
47	bitmap->real_end = real_end;
48	bitmap->base_error_code = EXT2_ET_BAD_GENERIC_MARK;
49	if (descr) {
50		retval = ext2fs_get_mem(strlen(descr)+1, &bitmap->description);
51		if (retval) {
52			ext2fs_free_mem(&bitmap);
53			return retval;
54		}
55		strcpy(bitmap->description, descr);
56	} else
57		bitmap->description = 0;
58
59	size = (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1);
60	retval = ext2fs_get_mem(size, &bitmap->bitmap);
61	if (retval) {
62		ext2fs_free_mem(&bitmap->description);
63		ext2fs_free_mem(&bitmap);
64		return retval;
65	}
66
67	if (init_map)
68		memcpy(bitmap->bitmap, init_map, size);
69	else
70		memset(bitmap->bitmap, 0, size);
71	*ret = bitmap;
72	return 0;
73}
74
75errcode_t ext2fs_allocate_generic_bitmap(__u32 start,
76					 __u32 end,
77					 __u32 real_end,
78					 const char *descr,
79					 ext2fs_generic_bitmap *ret)
80{
81	return make_bitmap(start, end, real_end, descr, 0, ret);
82}
83
84errcode_t ext2fs_copy_bitmap(ext2fs_generic_bitmap src,
85			     ext2fs_generic_bitmap *dest)
86{
87	errcode_t		retval;
88	ext2fs_generic_bitmap	new_map;
89
90	retval = make_bitmap(src->start, src->end, src->real_end,
91			     src->description, src->bitmap, &new_map);
92	if (retval)
93		return retval;
94	new_map->magic = src->magic;
95	new_map->fs = src->fs;
96	new_map->base_error_code = src->base_error_code;
97	*dest = new_map;
98	return 0;
99}
100
101void ext2fs_set_bitmap_padding(ext2fs_generic_bitmap map)
102{
103	__u32	i, j;
104
105	/* Protect loop from wrap-around if map->real_end is maxed */
106	for (i=map->end+1, j = i - map->start;
107	     i <= map->real_end && i > map->end;
108	     i++, j++)
109		ext2fs_set_bit(j, map->bitmap);
110
111	return;
112}
113
114errcode_t ext2fs_allocate_inode_bitmap(ext2_filsys fs,
115				       const char *descr,
116				       ext2fs_inode_bitmap *ret)
117{
118	ext2fs_inode_bitmap bitmap;
119	errcode_t	retval;
120	__u32		start, end, real_end;
121
122	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
123
124	fs->write_bitmaps = ext2fs_write_bitmaps;
125
126	start = 1;
127	end = fs->super->s_inodes_count;
128	real_end = (EXT2_INODES_PER_GROUP(fs->super) * fs->group_desc_count);
129
130	retval = ext2fs_allocate_generic_bitmap(start, end, real_end,
131						descr, &bitmap);
132	if (retval)
133		return retval;
134
135	bitmap->magic = EXT2_ET_MAGIC_INODE_BITMAP;
136	bitmap->fs = fs;
137	bitmap->base_error_code = EXT2_ET_BAD_INODE_MARK;
138
139	*ret = bitmap;
140	return 0;
141}
142
143errcode_t ext2fs_allocate_block_bitmap(ext2_filsys fs,
144				       const char *descr,
145				       ext2fs_block_bitmap *ret)
146{
147	ext2fs_block_bitmap bitmap;
148	errcode_t	retval;
149	__u32		start, end, real_end;
150
151	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
152
153	fs->write_bitmaps = ext2fs_write_bitmaps;
154
155	start = fs->super->s_first_data_block;
156	end = fs->super->s_blocks_count-1;
157	real_end = (EXT2_BLOCKS_PER_GROUP(fs->super)
158		    * fs->group_desc_count)-1 + start;
159
160	retval = ext2fs_allocate_generic_bitmap(start, end, real_end,
161						descr, &bitmap);
162	if (retval)
163		return retval;
164
165	bitmap->magic = EXT2_ET_MAGIC_BLOCK_BITMAP;
166	bitmap->fs = fs;
167	bitmap->base_error_code = EXT2_ET_BAD_BLOCK_MARK;
168
169	*ret = bitmap;
170	return 0;
171}
172
173errcode_t ext2fs_fudge_inode_bitmap_end(ext2fs_inode_bitmap bitmap,
174					ext2_ino_t end, ext2_ino_t *oend)
175{
176	EXT2_CHECK_MAGIC(bitmap, EXT2_ET_MAGIC_INODE_BITMAP);
177
178	if (end > bitmap->real_end)
179		return EXT2_ET_FUDGE_INODE_BITMAP_END;
180	if (oend)
181		*oend = bitmap->end;
182	bitmap->end = end;
183	return 0;
184}
185
186errcode_t ext2fs_fudge_block_bitmap_end(ext2fs_block_bitmap bitmap,
187					blk_t end, blk_t *oend)
188{
189	EXT2_CHECK_MAGIC(bitmap, EXT2_ET_MAGIC_BLOCK_BITMAP);
190
191	if (end > bitmap->real_end)
192		return EXT2_ET_FUDGE_BLOCK_BITMAP_END;
193	if (oend)
194		*oend = bitmap->end;
195	bitmap->end = end;
196	return 0;
197}
198
199void ext2fs_clear_inode_bitmap(ext2fs_inode_bitmap bitmap)
200{
201	if (!bitmap || (bitmap->magic != EXT2_ET_MAGIC_INODE_BITMAP))
202		return;
203
204	memset(bitmap->bitmap, 0,
205	       (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1));
206}
207
208void ext2fs_clear_block_bitmap(ext2fs_block_bitmap bitmap)
209{
210	if (!bitmap || (bitmap->magic != EXT2_ET_MAGIC_BLOCK_BITMAP))
211		return;
212
213	memset(bitmap->bitmap, 0,
214	       (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1));
215}
216