e2fsprogs/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 int 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_mem(len, &dblist->list);
  89         if (retval)
  90                 goto cleanup;
  91
  92         if (list)
  93                 memcpy(dblist->list, list, len);
  94         else
  95                 memset(dblist->list, 0, len);
  96         if (ret_dblist)
  97                 *ret_dblist = dblist;
  98         else
  99                 fs->dblist = dblist;
 100         return 0;
 101 cleanup:
 102         ext2fs_free_mem(&dblist);
 103         return retval;
 104 }
 105
 106 /*
 107  * Initialize a directory block list
 108  */
 109 errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
 110 {
 111         ext2_dblist     dblist;
 112         errcode_t       retval;
 113
 114         retval = make_dblist(fs, 0, 0, 0, &dblist);
 115         if (retval)
 116                 return retval;
 117
 118         dblist->sorted = 1;
 119         if (ret_dblist)
 120                 *ret_dblist = dblist;
 121         else
 122                 fs->dblist = dblist;
 123
 124         return 0;
 125 }
 126
 127 /*
 128  * Copy a directory block list
 129  */
 130 errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
 131 {
 132         ext2_dblist     dblist;
 133         errcode_t       retval;
 134
 135         retval = make_dblist(src->fs, src->size, src->count, src->list,
 136                              &dblist);
 137         if (retval)
 138                 return retval;
 139         dblist->sorted = src->sorted;
 140         *dest = dblist;
 141         return 0;
 142 }
 143
 144 /*
 145  * Close a directory block list
 146  *
 147  * (moved to closefs.c)
 148  */
 149
 150
 151 /*
 152  * Add a directory block to the directory block list
 153  */
 154 errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
 155                                int blockcnt)
 156 {
 157         struct ext2_db_entry    *new_entry;
 158         errcode_t               retval;
 159         unsigned long           old_size;
 160
 161         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 162
 163         if (dblist->count >= dblist->size) {
 164                 old_size = dblist->size * sizeof(struct ext2_db_entry);
 165                 dblist->size += 100;
 166                 retval = ext2fs_resize_mem(old_size, (size_t) dblist->size *
 167                                            sizeof(struct ext2_db_entry),
 168                                            &dblist->list);
 169                 if (retval) {
 170                         dblist->size -= 100;
 171                         return retval;
 172                 }
 173         }
 174         new_entry = dblist->list + ( (int) dblist->count++);
 175         new_entry->blk = blk;
 176         new_entry->ino = ino;
 177         new_entry->blockcnt = blockcnt;
 178
 179         dblist->sorted = 0;
 180
 181         return 0;
 182 }
 183
 184 /*
 185  * Change the directory block to the directory block list
 186  */
 187 errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
 188                                int blockcnt)
 189 {
 190         dgrp_t                  i;
 191
 192         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 193
 194         for (i=0; i < dblist->count; i++) {
 195                 if ((dblist->list[i].ino != ino) ||
 196                     (dblist->list[i].blockcnt != blockcnt))
 197                         continue;
 198                 dblist->list[i].blk = blk;
 199                 dblist->sorted = 0;
 200                 return 0;
 201         }
 202         return EXT2_ET_DB_NOT_FOUND;
 203 }
 204
 205 void ext2fs_dblist_sort(ext2_dblist dblist,
 206                         int (*sortfunc)(const void *,
 207                                                     const void *))
 208 {
 209         if (!sortfunc)
 210                 sortfunc = dir_block_cmp;
 211         qsort(dblist->list, (size_t) dblist->count,
 212               sizeof(struct ext2_db_entry), sortfunc);
 213         dblist->sorted = 1;
 214 }
 215
 216 /*
 217  * This function iterates over the directory block list
 218  */
 219 errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
 220                                 int (*func)(ext2_filsys fs,
 221                                             struct ext2_db_entry *db_info,
 222                                             void        *priv_data),
 223                                 void *priv_data)
 224 {
 225         ext2_ino_t      i;
 226         int             ret;
 227
 228         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 229
 230         if (!dblist->sorted)
 231                 ext2fs_dblist_sort(dblist, 0);
 232         for (i=0; i < dblist->count; i++) {
 233                 ret = (*func)(dblist->fs, &dblist->list[(int)i], priv_data);
 234                 if (ret & DBLIST_ABORT)
 235                         return 0;
 236         }
 237         return 0;
 238 }
 239
 240 static int dir_block_cmp(const void *a, const void *b)
 241 {
 242         const struct ext2_db_entry *db_a =
 243                 (const struct ext2_db_entry *) a;
 244         const struct ext2_db_entry *db_b =
 245                 (const struct ext2_db_entry *) b;
 246
 247         if (db_a->blk != db_b->blk)
 248                 return (int) (db_a->blk - db_b->blk);
 249
 250         if (db_a->ino != db_b->ino)
 251                 return (int) (db_a->ino - db_b->ino);
 252
 253         return (int) (db_a->blockcnt - db_b->blockcnt);
 254 }
 255
 256 int ext2fs_dblist_count(ext2_dblist dblist)
 257 {
 258         return (int) dblist->count;
 259 }