source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/ext2fs/dblist.c@ 821

/*
 * dblist.c -- directory block list functions
 *
 * Copyright 1997 by Theodore Ts'o
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 *
 */

#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <string.h>
#include <time.h>

#include "ext2_fs.h"
#include "ext2fsP.h"

static int dir_block_cmp(const void *a, const void *b);

/*
 * Returns the number of directories in the filesystem as reported by
 * the group descriptors.  Of course, the group descriptors could be
 * wrong!
 */
errcode_t ext2fs_get_num_dirs(ext2_filsys fs, ext2_ino_t *ret_num_dirs)
{
    dgrp_t  i;
    ext2_ino_t  num_dirs, max_dirs;

    EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

    num_dirs = 0;
    max_dirs = fs->super->s_inodes_per_group;
    for (i = 0; i < fs->group_desc_count; i++) {
        if (fs->group_desc[i].bg_used_dirs_count > max_dirs)
            num_dirs += max_dirs / 8;
        else
            num_dirs += fs->group_desc[i].bg_used_dirs_count;
    }
    if (num_dirs > fs->super->s_inodes_count)
        num_dirs = fs->super->s_inodes_count;

    *ret_num_dirs = num_dirs;

    return 0;
}

/*
 * helper function for making a new directory block list (for
 * initialize and copy).
 */
static errcode_t make_dblist(ext2_filsys fs, ext2_ino_t size, ext2_ino_t count,
                 struct ext2_db_entry *list,
                 ext2_dblist *ret_dblist)
{
    ext2_dblist dblist;
    errcode_t   retval;
    size_t      len;

    EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

    if ((ret_dblist == 0) && fs->dblist &&
        (fs->dblist->magic == EXT2_ET_MAGIC_DBLIST))
        return 0;

    retval = ext2fs_get_mem(sizeof(struct ext2_struct_dblist), &dblist);
    if (retval)
        return retval;
    memset(dblist, 0, sizeof(struct ext2_struct_dblist));

    dblist->magic = EXT2_ET_MAGIC_DBLIST;
    dblist->fs = fs;
    if (size)
        dblist->size = size;
    else {
        retval = ext2fs_get_num_dirs(fs, &dblist->size);
        if (retval)
            goto cleanup;
        dblist->size = (dblist->size * 2) + 12;
    }
    len = (size_t) sizeof(struct ext2_db_entry) * dblist->size;
    dblist->count = count;
    retval = ext2fs_get_mem(len, &dblist->list);
    if (retval)
        goto cleanup;

    if (list)
        memcpy(dblist->list, list, len);
    else
        memset(dblist->list, 0, len);
    if (ret_dblist)
        *ret_dblist = dblist;
    else
        fs->dblist = dblist;
    return 0;
cleanup:
    ext2fs_free_mem(&dblist);
    return retval;
}

/*
 * Initialize a directory block list
 */
errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
{
    ext2_dblist dblist;
    errcode_t   retval;

    retval = make_dblist(fs, 0, 0, 0, &dblist);
    if (retval)
        return retval;

    dblist->sorted = 1;
    if (ret_dblist)
        *ret_dblist = dblist;
    else
        fs->dblist = dblist;

    return 0;
}

/*
 * Copy a directory block list
 */
errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
{
    ext2_dblist dblist;
    errcode_t   retval;

    retval = make_dblist(src->fs, src->size, src->count, src->list,
                 &dblist);
    if (retval)
        return retval;
    dblist->sorted = src->sorted;
    *dest = dblist;
    return 0;
}

/*
 * Close a directory block list
 *
 * (moved to closefs.c)
 */


/*
 * Add a directory block to the directory block list
 */
errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
                   int blockcnt)
{
    struct ext2_db_entry    *new_entry;
    errcode_t       retval;
    unsigned long       old_size;

    EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);

    if (dblist->count >= dblist->size) {
        old_size = dblist->size * sizeof(struct ext2_db_entry);
        dblist->size += 100;
        retval = ext2fs_resize_mem(old_size, (size_t) dblist->size *
                       sizeof(struct ext2_db_entry),
                       &dblist->list);
        if (retval) {
            dblist->size -= 100;
            return retval;
        }
    }
    new_entry = dblist->list + ( (int) dblist->count++);
    new_entry->blk = blk;
    new_entry->ino = ino;
    new_entry->blockcnt = blockcnt;

    dblist->sorted = 0;

    return 0;
}

/*
 * Change the directory block to the directory block list
 */
errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
                   int blockcnt)
{
    dgrp_t          i;

    EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);

    for (i=0; i < dblist->count; i++) {
        if ((dblist->list[i].ino != ino) ||
            (dblist->list[i].blockcnt != blockcnt))
            continue;
        dblist->list[i].blk = blk;
        dblist->sorted = 0;
        return 0;
    }
    return EXT2_ET_DB_NOT_FOUND;
}

void ext2fs_dblist_sort(ext2_dblist dblist,
            int (*sortfunc)(const void *,
                            const void *))
{
    if (!sortfunc)
        sortfunc = dir_block_cmp;
    qsort(dblist->list, (size_t) dblist->count,
          sizeof(struct ext2_db_entry), sortfunc);
    dblist->sorted = 1;
}

/*
 * This function iterates over the directory block list
 */
errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
                int (*func)(ext2_filsys fs,
                        struct ext2_db_entry *db_info,
                        void    *priv_data),
                void *priv_data)
{
    ext2_ino_t  i;
    int     ret;

    EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);

    if (!dblist->sorted)
        ext2fs_dblist_sort(dblist, 0);
    for (i=0; i < dblist->count; i++) {
        ret = (*func)(dblist->fs, &dblist->list[(int)i], priv_data);
        if (ret & DBLIST_ABORT)
            return 0;
    }
    return 0;
}

static int dir_block_cmp(const void *a, const void *b)
{
    const struct ext2_db_entry *db_a =
        (const struct ext2_db_entry *) a;
    const struct ext2_db_entry *db_b =
        (const struct ext2_db_entry *) b;

    if (db_a->blk != db_b->blk)
        return (int) (db_a->blk - db_b->blk);

    if (db_a->ino != db_b->ino)
        return (int) (db_a->ino - db_b->ino);

    return (int) (db_a->blockcnt - db_b->blockcnt);
}

int ext2fs_dblist_count(ext2_dblist dblist)
{
    return (int) dblist->count;
}