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 <stdlib.h>
  18 #include <string.h>
  19 #include <time.h>
  20 #ifdef HAVE_ERRNO_H
  21 #include <errno.h>
  22 #endif
  23
  24 #include <linux/ext2_fs.h>
  25
  26 #include "ext2fsP.h"
  27
  28 static int dir_block_cmp(const void *a, const void *b);
  29
  30 /*
  31  * Returns the number of directories in the filesystem as reported by
  32  * the group descriptors.  Of course, the group descriptors could be
  33  * wrong!
  34  */
  35 errcode_t ext2fs_get_num_dirs(ext2_filsys fs, ino_t *ret_num_dirs)
  36 {
  37         int     i;
  38         ino_t   num_dirs;
  39
  40         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  41
  42         num_dirs = 0;
  43         for (i = 0; i < fs->group_desc_count; i++)
  44                 num_dirs += fs->group_desc[i].bg_used_dirs_count;
  45
  46         *ret_num_dirs = num_dirs;
  47
  48         return 0;
  49 }
  50
  51 /*
  52  * helper function for making a new directory block list (for
  53  * initialize and copy).
  54  */
  55 static errcode_t make_dblist(ext2_filsys fs, ino_t size, ino_t count,
  56                              struct ext2_db_entry *list,
  57                              ext2_dblist *ret_dblist)
  58 {
  59         ext2_dblist     dblist;
  60         errcode_t       retval;
  61         size_t          len;
  62
  63         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  64
  65         if ((ret_dblist == 0) && fs->dblist &&
  66             (fs->dblist->magic == EXT2_ET_MAGIC_DBLIST))
  67                 return 0;
  68
  69         dblist = malloc(sizeof(struct ext2_struct_dblist));
  70         if (!dblist)
  71                 return ENOMEM;
  72         memset(dblist, 0, sizeof(struct ext2_struct_dblist));
  73
  74         dblist->magic = EXT2_ET_MAGIC_DBLIST;
  75         dblist->fs = fs;
  76         if (size)
  77                 dblist->size = size;
  78         else {
  79                 retval = ext2fs_get_num_dirs(fs, &dblist->size);
  80                 if (retval)
  81                         goto cleanup;
  82                 dblist->size = (dblist->size * 2) + 12;
  83         }
  84         len = (size_t) sizeof(struct ext2_db_entry) * dblist->size;
  85         dblist->count = count;
  86         dblist->list = malloc(len);
  87         if (dblist->list == NULL) {
  88                 retval = ENOMEM;
  89                 goto cleanup;
  90         }
  91         if (list)
  92                 memcpy(dblist->list, list, len);
  93         else
  94                 memset(dblist->list, 0, len);
  95         *ret_dblist = dblist;
  96         return 0;
  97 cleanup:
  98         if (dblist)
  99                 free(dblist);
 100         return retval;
 101 }
 102
 103 /*
 104  * Initialize a directory block list
 105  */
 106 errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
 107 {
 108         ext2_dblist     dblist;
 109         errcode_t       retval;
 110
 111         retval = make_dblist(fs, 0, 0, 0, &dblist);
 112         if (retval)
 113                 return retval;
 114
 115         dblist->sorted = 1;
 116         if (ret_dblist)
 117                 *ret_dblist = dblist;
 118         else
 119                 fs->dblist = dblist;
 120
 121         return 0;
 122 }
 123
 124 /*
 125  * Copy a directory block list
 126  */
 127 errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
 128 {
 129         ext2_dblist     dblist;
 130         errcode_t       retval;
 131
 132         retval = make_dblist(src->fs, src->size, src->count, src->list,
 133                              &dblist);
 134         if (retval)
 135                 return retval;
 136         dblist->sorted = src->sorted;
 137         *dest = dblist;
 138         return 0;
 139 }
 140
 141 /*
 142  * Close a directory block list
 143  *
 144  * (moved to closefs.c)
 145  */
 146
 147
 148 /*
 149  * Add a directory block to the directory block list
 150  */
 151 errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ino_t ino, blk_t blk,
 152                                int blockcnt)
 153 {
 154         struct ext2_db_entry    *nlist, *new;
 155
 156         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 157
 158         if (dblist->count >= dblist->size) {
 159                 dblist->size += 100;
 160                 nlist = realloc(dblist->list, (size_t) dblist->size *
 161                                 sizeof(struct ext2_db_entry));
 162                 if (nlist == 0) {
 163                         dblist->size -= 100;
 164                         return ENOMEM;
 165                 }
 166                 dblist->list = nlist;
 167         }
 168         new = dblist->list + ( (int) dblist->count++);
 169         new->blk = blk;
 170         new->ino = ino;
 171         new->blockcnt = blockcnt;
 172
 173         dblist->sorted = 0;
 174
 175         return 0;
 176 }
 177
 178 /*
 179  * Change the directory block to the directory block list
 180  */
 181 errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ino_t ino, blk_t blk,
 182                                int blockcnt)
 183 {
 184         int                     i;
 185
 186         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 187
 188         for (i=0; i < dblist->count; i++) {
 189                 if ((dblist->list[i].ino != ino) ||
 190                     (dblist->list[i].blockcnt != blockcnt))
 191                         continue;
 192                 dblist->list[i].blk = blk;
 193                 dblist->sorted = 0;
 194                 return 0;
 195         }
 196         return ENOENT;
 197 }
 198
 199 /*
 200  * This function iterates over the directory block list
 201  */
 202 errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
 203                                 int (*func)(ext2_filsys fs,
 204                                             struct ext2_db_entry *db_info,
 205                                             void        *private),
 206                                 void *private)
 207 {
 208         ino_t   i;
 209         int     ret;
 210
 211         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 212
 213         if (!dblist->sorted) {
 214                 qsort(dblist->list, (size_t) dblist->count,
 215                       sizeof(struct ext2_db_entry), dir_block_cmp);
 216                 dblist->sorted = 1;
 217         }
 218         for (i=0; i < dblist->count; i++) {
 219                 ret = (*func)(dblist->fs, &dblist->list[(int)i], private);
 220                 if (ret & DBLIST_ABORT)
 221                         return 0;
 222         }
 223         return 0;
 224 }
 225
 226
 227 static int dir_block_cmp(const void *a, const void *b)
 228 {
 229         const struct ext2_db_entry *db_a =
 230                 (const struct ext2_db_entry *) a;
 231         const struct ext2_db_entry *db_b =
 232                 (const struct ext2_db_entry *) b;
 233
 234         if (db_a->blk != db_b->blk)
 235                 return (int) (db_a->blk - db_b->blk);
 236
 237         if (db_a->ino != db_b->ino)
 238                 return (int) (db_a->ino - db_b->ino);
 239
 240         return (int) (db_a->blockcnt - db_b->blockcnt);
 241 }
 242
 243 int ext2fs_dblist_count(ext2_dblist dblist)
 244 {
 245         return (int) dblist->count;
 246 }