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 #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
  23 static 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  */
  30 errcode_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  */
  57 static 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;
 102 cleanup:
 103         if (dblist)
 104                 ext2fs_free_mem(&dblist);
 105         return retval;
 106 }
 107
 108 /*
 109  * Initialize a directory block list
 110  */
 111 errcode_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  */
 132 errcode_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  */
 156 errcode_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  */
 189 errcode_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
 207 void 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  */
 221 errcode_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
 242 static 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
 258 int ext2fs_dblist_count(ext2_dblist dblist)
 259 {
 260         return (int) dblist->count;
 261 }
 262
 263 errcode_t ext2fs_dblist_get_last(ext2_dblist dblist,
 264                                  struct ext2_db_entry **entry)
 265 {
 266         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 267
 268         if (dblist->count == 0)
 269                 return EXT2_ET_DBLIST_EMPTY;
 270
 271         if (entry)
 272                 *entry = dblist->list + ( (int) dblist->count-1);
 273         return 0;
 274 }
 275
 276 errcode_t ext2fs_dblist_drop_last(ext2_dblist dblist)
 277 {
 278         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 279
 280         if (dblist->count == 0)
 281                 return EXT2_ET_DBLIST_EMPTY;
 282
 283         dblist->count--;
 284         return 0;
 285 }