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