lib/ext2fs/dblist.c

   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 #include <unistd.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <time.h>
  18 #ifdef HAVE_ERRNO_H
  19 #include <errno.h>
  20 #endif
  21
  22 #include <linux/ext2_fs.h>
  23
  24 #include "ext2fsP.h"
  25
  26 static int dir_block_cmp(const void *a, const void *b);
  27
  28 /*
  29  * Returns the number of directories in the filesystem as reported by
  30  * the group descriptors.  Of course, the group descriptors could be
  31  * wrong!
  32  */
  33 errcode_t ext2fs_get_num_dirs(ext2_filsys fs, ino_t *ret_num_dirs)
  34 {
  35         int     i;
  36         ino_t   num_dirs;
  37
  38         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  39
  40         num_dirs = 0;
  41         for (i = 0; i < fs->group_desc_count; i++)
  42                 num_dirs += fs->group_desc[i].bg_used_dirs_count;
  43
  44         *ret_num_dirs = num_dirs;
  45
  46         return 0;
  47 }
  48
  49 /*
  50  * helper function for making a new directory block list (for
  51  * initialize and copy).
  52  */
  53 static errcode_t make_dblist(ext2_filsys fs, ino_t size, ino_t count,
  54                              struct ext2_db_entry *list,
  55                              ext2_dblist *ret_dblist)
  56 {
  57         ext2_dblist     dblist;
  58         errcode_t       retval;
  59         size_t          len;
  60
  61         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  62
  63         if ((ret_dblist == 0) && fs->dblist &&
  64             (fs->dblist->magic == EXT2_ET_MAGIC_DBLIST))
  65                 return 0;
  66
  67         dblist = malloc(sizeof(struct ext2_struct_dblist));
  68         if (!dblist)
  69                 return ENOMEM;
  70         memset(dblist, 0, sizeof(struct ext2_struct_dblist));
  71
  72         dblist->magic = EXT2_ET_MAGIC_DBLIST;
  73         dblist->fs = fs;
  74         if (size)
  75                 dblist->size = size;
  76         else {
  77                 retval = ext2fs_get_num_dirs(fs, &dblist->size);
  78                 if (retval)
  79                         goto cleanup;
  80         }
  81         len = sizeof(struct ext2_db_entry) * dblist->size;
  82         dblist->count = count;
  83         dblist->list = malloc(len);
  84         if (dblist->list == NULL) {
  85                 retval = ENOMEM;
  86                 goto cleanup;
  87         }
  88         if (list)
  89                 memcpy(dblist->list, list, len);
  90         else
  91                 memset(dblist->list, 0, len);
  92         *ret_dblist = dblist;
  93         return 0;
  94 cleanup:
  95         if (dblist)
  96                 free(dblist);
  97         return retval;
  98 }
  99
 100 /*
 101  * Initialize a directory block list
 102  */
 103 errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
 104 {
 105         ext2_dblist     dblist;
 106         errcode_t       retval;
 107
 108         retval = make_dblist(fs, 0, 0, 0, &dblist);
 109         if (retval)
 110                 return retval;
 111
 112         dblist->sorted = 1;
 113         if (ret_dblist)
 114                 *ret_dblist = dblist;
 115         else
 116                 fs->dblist = dblist;
 117
 118         return 0;
 119 }
 120
 121 /*
 122  * Copy a directory block list
 123  */
 124 errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
 125 {
 126         ext2_dblist     dblist;
 127         errcode_t       retval;
 128
 129         retval = make_dblist(src->fs, src->size, src->count, src->list,
 130                              &dblist);
 131         if (retval)
 132                 return retval;
 133         dblist->sorted = src->sorted;
 134         *dest = dblist;
 135         return 0;
 136 }
 137
 138 /*
 139  * Close a directory block list
 140  *
 141  * (moved to closefs.c)
 142  */
 143
 144
 145 /*
 146  * Add a directory block to the directory block list
 147  */
 148 errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ino_t ino, blk_t blk,
 149                                int blockcnt)
 150 {
 151         struct ext2_db_entry    *nlist, *new;
 152
 153         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 154
 155         if (dblist->count >= dblist->size) {
 156                 dblist->size += 100;
 157                 nlist = realloc(dblist->list,
 158                                 dblist->size * sizeof(struct ext2_db_entry));
 159                 if (nlist == 0) {
 160                         dblist->size -= 100;
 161                         return ENOMEM;
 162                 }
 163                 dblist->list = nlist;
 164         }
 165         new = dblist->list + dblist->count++;
 166         new->blk = blk;
 167         new->ino = ino;
 168         new->blockcnt = blockcnt;
 169
 170         dblist->sorted = 0;
 171
 172         return 0;
 173 }
 174
 175 /*
 176  * Change the directory block to the directory block list
 177  */
 178 errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ino_t ino, blk_t blk,
 179                                int blockcnt)
 180 {
 181         struct ext2_db_entry    *ent;
 182         int                     i;
 183
 184         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 185
 186         for (i=0; i < dblist->count; i++) {
 187                 if ((dblist->list[i].ino != ino) ||
 188                     (dblist->list[i].blockcnt != blockcnt))
 189                         continue;
 190                 dblist->list[i].blk = blk;
 191                 dblist->sorted = 0;
 192                 return 0;
 193         }
 194         return ENOENT;
 195 }
 196
 197 /*
 198  * This function iterates over the directory block list
 199  */
 200 errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
 201                                 int (*func)(ext2_filsys fs,
 202                                             struct ext2_db_entry *db_info,
 203                                             void        *private),
 204                                 void *private)
 205 {
 206         ino_t   i;
 207         int     ret;
 208
 209         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 210
 211         if (!dblist->sorted) {
 212                 qsort(dblist->list, dblist->count,
 213                       sizeof(struct ext2_db_entry), dir_block_cmp);
 214                 dblist->sorted = 1;
 215         }
 216         for (i=0; i < dblist->count; i++) {
 217                 ret = (*func)(dblist->fs, &dblist->list[i], private);
 218                 if (ret & DBLIST_ABORT)
 219                         return 0;
 220         }
 221         return 0;
 222 }
 223
 224
 225 static int dir_block_cmp(const void *a, const void *b)
 226 {
 227         const struct ext2_db_entry *db_a =
 228                 (const struct ext2_db_entry *) a;
 229         const struct ext2_db_entry *db_b =
 230                 (const struct ext2_db_entry *) b;
 231
 232         if (db_a->blk != db_b->blk)
 233                 return (db_a->blk - db_b->blk);
 234
 235         if (db_a->ino != db_b->ino)
 236                 return (db_a->ino - db_b->ino);
 237
 238         return (db_a->blockcnt - db_b->blockcnt);
 239 }
 240
 241