dblist.c revision 52b1dd5e496c199e9cbcc238f26fd2264a07a2cf 
1/*
2 * dblist.c -- directory block list functions
3 *
4 * Copyright 1997 by 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
13#include <stdio.h>
14#if HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17#include <string.h>
18#include <time.h>
19
20#include "ext2_fs.h"
21#include "ext2fsP.h"
22
23static EXT2_QSORT_TYPE dir_block_cmp(const void *a, const void *b);
24
25/*
26 * Returns the number of directories in the filesystem as reported by
27 * the group descriptors.  Of course, the group descriptors could be
28 * wrong!
29 */
30errcode_t ext2fs_get_num_dirs(ext2_filsys fs, ext2_ino_t *ret_num_dirs)
31{
32	dgrp_t	i;
33	ext2_ino_t	num_dirs, max_dirs;
34
35	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
36
37	num_dirs = 0;
38	max_dirs = fs->super->s_inodes_per_group;
39	for (i = 0; i < fs->group_desc_count; i++) {
40		if (fs->group_desc[i].bg_used_dirs_count > max_dirs)
41			num_dirs += max_dirs / 8;
42		else
43			num_dirs += fs->group_desc[i].bg_used_dirs_count;
44	}
45	if (num_dirs > fs->super->s_inodes_count)
46		num_dirs = fs->super->s_inodes_count;
47
48	*ret_num_dirs = num_dirs;
49
50	return 0;
51}
52
53/*
54 * helper function for making a new directory block list (for
55 * initialize and copy).
56 */
57static errcode_t make_dblist(ext2_filsys fs, ext2_ino_t size, ext2_ino_t count,
58			     struct ext2_db_entry *list,
59			     ext2_dblist *ret_dblist)
60{
61	ext2_dblist	dblist;
62	errcode_t	retval;
63	size_t		len;
64
65	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
66
67	if ((ret_dblist == 0) && fs->dblist &&
68	    (fs->dblist->magic == EXT2_ET_MAGIC_DBLIST))
69		return 0;
70
71	retval = ext2fs_get_mem(sizeof(struct ext2_struct_dblist), &dblist);
72	if (retval)
73		return retval;
74	memset(dblist, 0, sizeof(struct ext2_struct_dblist));
75
76	dblist->magic = EXT2_ET_MAGIC_DBLIST;
77	dblist->fs = fs;
78	if (size)
79		dblist->size = size;
80	else {
81		retval = ext2fs_get_num_dirs(fs, &dblist->size);
82		if (retval)
83			goto cleanup;
84		dblist->size = (dblist->size * 2) + 12;
85	}
86	len = (size_t) sizeof(struct ext2_db_entry) * dblist->size;
87	dblist->count = count;
88	retval = ext2fs_get_array(dblist->size, sizeof(struct ext2_db_entry),
89		&dblist->list);
90	if (retval)
91		goto cleanup;
92
93	if (list)
94		memcpy(dblist->list, list, len);
95	else
96		memset(dblist->list, 0, len);
97	if (ret_dblist)
98		*ret_dblist = dblist;
99	else
100		fs->dblist = dblist;
101	return 0;
102cleanup:
103	if (dblist)
104		ext2fs_free_mem(&dblist);
105	return retval;
106}
107
108/*
109 * Initialize a directory block list
110 */
111errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
112{
113	ext2_dblist	dblist;
114	errcode_t	retval;
115
116	retval = make_dblist(fs, 0, 0, 0, &dblist);
117	if (retval)
118		return retval;
119
120	dblist->sorted = 1;
121	if (ret_dblist)
122		*ret_dblist = dblist;
123	else
124		fs->dblist = dblist;
125
126	return 0;
127}
128
129/*
130 * Copy a directory block list
131 */
132errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
133{
134	ext2_dblist	dblist;
135	errcode_t	retval;
136
137	retval = make_dblist(src->fs, src->size, src->count, src->list,
138			     &dblist);
139	if (retval)
140		return retval;
141	dblist->sorted = src->sorted;
142	*dest = dblist;
143	return 0;
144}
145
146/*
147 * Close a directory block list
148 *
149 * (moved to closefs.c)
150 */
151
152
153/*
154 * Add a directory block to the directory block list
155 */
156errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
157			       int blockcnt)
158{
159	struct ext2_db_entry 	*new_entry;
160	errcode_t		retval;
161	unsigned long		old_size;
162
163	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
164
165	if (dblist->count >= dblist->size) {
166		old_size = dblist->size * sizeof(struct ext2_db_entry);
167		dblist->size += 100;
168		retval = ext2fs_resize_mem(old_size, (size_t) dblist->size *
169					   sizeof(struct ext2_db_entry),
170					   &dblist->list);
171		if (retval) {
172			dblist->size -= 100;
173			return retval;
174		}
175	}
176	new_entry = dblist->list + ( (int) dblist->count++);
177	new_entry->blk = blk;
178	new_entry->ino = ino;
179	new_entry->blockcnt = blockcnt;
180
181	dblist->sorted = 0;
182
183	return 0;
184}
185
186/*
187 * Change the directory block to the directory block list
188 */
189errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
190			       int blockcnt)
191{
192	dgrp_t			i;
193
194	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
195
196	for (i=0; i < dblist->count; i++) {
197		if ((dblist->list[i].ino != ino) ||
198		    (dblist->list[i].blockcnt != blockcnt))
199			continue;
200		dblist->list[i].blk = blk;
201		dblist->sorted = 0;
202		return 0;
203	}
204	return EXT2_ET_DB_NOT_FOUND;
205}
206
207void ext2fs_dblist_sort(ext2_dblist dblist,
208			EXT2_QSORT_TYPE (*sortfunc)(const void *,
209						    const void *))
210{
211	if (!sortfunc)
212		sortfunc = dir_block_cmp;
213	qsort(dblist->list, (size_t) dblist->count,
214	      sizeof(struct ext2_db_entry), sortfunc);
215	dblist->sorted = 1;
216}
217
218/*
219 * This function iterates over the directory block list
220 */
221errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
222				int (*func)(ext2_filsys fs,
223					    struct ext2_db_entry *db_info,
224					    void	*priv_data),
225				void *priv_data)
226{
227	ext2_ino_t	i;
228	int		ret;
229
230	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
231
232	if (!dblist->sorted)
233		ext2fs_dblist_sort(dblist, 0);
234	for (i=0; i < dblist->count; i++) {
235		ret = (*func)(dblist->fs, &dblist->list[(int)i], priv_data);
236		if (ret & DBLIST_ABORT)
237			return 0;
238	}
239	return 0;
240}
241
242static EXT2_QSORT_TYPE dir_block_cmp(const void *a, const void *b)
243{
244	const struct ext2_db_entry *db_a =
245		(const struct ext2_db_entry *) a;
246	const struct ext2_db_entry *db_b =
247		(const struct ext2_db_entry *) b;
248
249	if (db_a->blk != db_b->blk)
250		return (int) (db_a->blk - db_b->blk);
251
252	if (db_a->ino != db_b->ino)
253		return (int) (db_a->ino - db_b->ino);
254
255	return (int) (db_a->blockcnt - db_b->blockcnt);
256}
257
258int ext2fs_dblist_count(ext2_dblist dblist)
259{
260	return (int) dblist->count;
261}
262
263errcode_t ext2fs_dblist_get_last(ext2_dblist dblist,
264				 struct ext2_db_entry **entry)
265{
266	errcode_t		retval;
267
268	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
269
270	if (dblist->count == 0)
271		return EXT2_ET_DBLIST_EMPTY;
272
273	if (entry)
274		*entry = dblist->list + ( (int) dblist->count-1);
275	return 0;
276}
277
278errcode_t ext2fs_dblist_drop_last(ext2_dblist dblist)
279{
280	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
281
282	if (dblist->count == 0)
283		return EXT2_ET_DBLIST_EMPTY;
284
285	dblist->count--;
286	return 0;
287}
288