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 #if EXT2_FLAT_INCLUDES
  21 #include "ext2_fs.h"
  22 #else
  23 #include <linux/ext2_fs.h>
  24 #endif
  25
  26 #include "ext2fsP.h"
  27
  28 static EXT2_QSORT_TYPE 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         dgrp_t  i;
  38         ino_t   num_dirs, max_dirs;
  39
  40         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  41
  42         num_dirs = 0;
  43         max_dirs = fs->super->s_inodes_per_group;
  44         for (i = 0; i < fs->group_desc_count; i++) {
  45                 if (fs->group_desc[i].bg_used_dirs_count > max_dirs)
  46                         num_dirs += max_dirs / 8;
  47                 else
  48                         num_dirs += fs->group_desc[i].bg_used_dirs_count;
  49         }
  50         if (num_dirs > fs->super->s_inodes_count)
  51                 num_dirs = fs->super->s_inodes_count;
  52
  53         *ret_num_dirs = num_dirs;
  54
  55         return 0;
  56 }
  57
  58 /*
  59  * helper function for making a new directory block list (for
  60  * initialize and copy).
  61  */
  62 static errcode_t make_dblist(ext2_filsys fs, ino_t size, ino_t count,
  63                              struct ext2_db_entry *list,
  64                              ext2_dblist *ret_dblist)
  65 {
  66         ext2_dblist     dblist;
  67         errcode_t       retval;
  68         size_t          len;
  69
  70         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  71
  72         if ((ret_dblist == 0) && fs->dblist &&
  73             (fs->dblist->magic == EXT2_ET_MAGIC_DBLIST))
  74                 return 0;
  75
  76         retval = ext2fs_get_mem(sizeof(struct ext2_struct_dblist),
  77                                 (void **) &dblist);
  78         if (retval)
  79                 return retval;
  80         memset(dblist, 0, sizeof(struct ext2_struct_dblist));
  81
  82         dblist->magic = EXT2_ET_MAGIC_DBLIST;
  83         dblist->fs = fs;
  84         if (size)
  85                 dblist->size = size;
  86         else {
  87                 retval = ext2fs_get_num_dirs(fs, &dblist->size);
  88                 if (retval)
  89                         goto cleanup;
  90                 dblist->size = (dblist->size * 2) + 12;
  91         }
  92         len = (size_t) sizeof(struct ext2_db_entry) * dblist->size;
  93         dblist->count = count;
  94         retval = ext2fs_get_mem(len, (void **) &dblist->list);
  95         if (retval)
  96                 goto cleanup;
  97
  98         if (list)
  99                 memcpy(dblist->list, list, len);
 100         else
 101                 memset(dblist->list, 0, len);
 102         if (ret_dblist)
 103                 *ret_dblist = dblist;
 104         else
 105                 fs->dblist = dblist;
 106         return 0;
 107 cleanup:
 108         if (dblist)
 109                 ext2fs_free_mem((void **) &dblist);
 110         return retval;
 111 }
 112
 113 /*
 114  * Initialize a directory block list
 115  */
 116 errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
 117 {
 118         ext2_dblist     dblist;
 119         errcode_t       retval;
 120
 121         retval = make_dblist(fs, 0, 0, 0, &dblist);
 122         if (retval)
 123                 return retval;
 124
 125         dblist->sorted = 1;
 126         if (ret_dblist)
 127                 *ret_dblist = dblist;
 128         else
 129                 fs->dblist = dblist;
 130
 131         return 0;
 132 }
 133
 134 /*
 135  * Copy a directory block list
 136  */
 137 errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
 138 {
 139         ext2_dblist     dblist;
 140         errcode_t       retval;
 141
 142         retval = make_dblist(src->fs, src->size, src->count, src->list,
 143                              &dblist);
 144         if (retval)
 145                 return retval;
 146         dblist->sorted = src->sorted;
 147         *dest = dblist;
 148         return 0;
 149 }
 150
 151 /*
 152  * Close a directory block list
 153  *
 154  * (moved to closefs.c)
 155  */
 156
 157
 158 /*
 159  * Add a directory block to the directory block list
 160  */
 161 errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ino_t ino, blk_t blk,
 162                                int blockcnt)
 163 {
 164         struct ext2_db_entry    *new_entry;
 165         errcode_t               retval;
 166         unsigned long           old_size;
 167
 168         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 169
 170         if (dblist->count >= dblist->size) {
 171                 old_size = dblist->size * sizeof(struct ext2_db_entry);
 172                 dblist->size += 100;
 173                 retval = ext2fs_resize_mem(old_size, (size_t) dblist->size *
 174                                            sizeof(struct ext2_db_entry),
 175                                            (void **) &dblist->list);
 176                 if (retval) {
 177                         dblist->size -= 100;
 178                         return retval;
 179                 }
 180         }
 181         new_entry = dblist->list + ( (int) dblist->count++);
 182         new_entry->blk = blk;
 183         new_entry->ino = ino;
 184         new_entry->blockcnt = blockcnt;
 185
 186         dblist->sorted = 0;
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * Change the directory block to the directory block list
 193  */
 194 errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ino_t ino, blk_t blk,
 195                                int blockcnt)
 196 {
 197         dgrp_t                  i;
 198
 199         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 200
 201         for (i=0; i < dblist->count; i++) {
 202                 if ((dblist->list[i].ino != ino) ||
 203                     (dblist->list[i].blockcnt != blockcnt))
 204                         continue;
 205                 dblist->list[i].blk = blk;
 206                 dblist->sorted = 0;
 207                 return 0;
 208         }
 209         return EXT2_ET_DB_NOT_FOUND;
 210 }
 211
 212 /*
 213  * This function iterates over the directory block list
 214  */
 215 errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
 216                                 int (*func)(ext2_filsys fs,
 217                                             struct ext2_db_entry *db_info,
 218                                             void        *priv_data),
 219                                 void *priv_data)
 220 {
 221         ino_t   i;
 222         int     ret;
 223
 224         EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
 225
 226         if (!dblist->sorted) {
 227                 qsort(dblist->list, (size_t) dblist->count,
 228                       sizeof(struct ext2_db_entry), dir_block_cmp);
 229                 dblist->sorted = 1;
 230         }
 231         for (i=0; i < dblist->count; i++) {
 232                 ret = (*func)(dblist->fs, &dblist->list[(int)i], priv_data);
 233                 if (ret & DBLIST_ABORT)
 234                         return 0;
 235         }
 236         return 0;
 237 }
 238
 239
 240 static EXT2_QSORT_TYPE 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 }