/* $Id: VBoxVolInfo.cpp $ */
/** @file
 * Apps - VBoxVolInfo, Volume information tool.
 */

/*
 * Copyright (C) 2012-2020 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 */



/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#include <dirent.h>
extern "C"
{
#define private privatekw
#include <libdevmapper.h>
}
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>


/*********************************************************************************************************************************
*   Function Prototypes                                                                                                          *
*********************************************************************************************************************************/
void print_dev_name(dev_t devid);

/*
 * Extracts logical volume dependencies via devmapper API and print them out.
 */
int main(int argc, char **argv)
{
    struct dm_task *dmtask;
    struct dm_info  dminfo;

    if (argc != 2)
    {
        fprintf(stderr, "USAGE: %s <volume_name>\n", argv[0]);
        return 1;
    }

    dmtask = dm_task_create(DM_DEVICE_DEPS);
    if (!dmtask)
        return 2;

    if (dm_task_set_name(dmtask, argv[1]))
        if (dm_task_run(dmtask))
            if (dm_task_get_info(dmtask, &dminfo))
            {
                struct dm_deps *dmdeps = dm_task_get_deps(dmtask);
                if (dmdeps)
                {
                    unsigned i;
                    for (i = 0; i < dmdeps->count; ++i)
                        print_dev_name(dmdeps->device[i]);
                }
            }

    dm_task_destroy(dmtask);
    return 0;
}

/*
 * Looks up device name by id using /dev directory. Prints it to stdout.
 */
void print_dev_name(dev_t devid)
{
    char path[PATH_MAX];
    struct dirent *de;
    DIR *dir = opendir("/dev");

    while ((de = readdir(dir)) != NULL)
    {
        struct stat st;
        snprintf(path, sizeof(path), "/dev/%s", de->d_name);
        if (!stat(path, &st))
            if (S_ISBLK(st.st_mode))
                if (devid == st.st_rdev)
                {
                    puts(de->d_name);
                    break;
                }
    }
    closedir(dir);
}