/*
 * Copyright (c) 2010 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Alex Hornung <ahornung@gmail.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/stat.h>
#include <devattr.h>
#include <errno.h>
#include "fsid.h"

static struct fsid_head fsid_list =
                TAILQ_HEAD_INITIALIZER(fsid_list);

static int
fsid_alias_exists(const char *dev)
{
        struct fsid_entry *fsid;
        int exists = 0;

        if (TAILQ_EMPTY(&fsid_list))
                return 0;

        TAILQ_FOREACH(fsid, &fsid_list, link) {
                if (strcmp(fsid->dev_path, dev) == 0) {
                        exists = 1;
                        break;
                }
        }

        return exists;
}

static int
fsid_check_create_alias(const char *dev)
{
        struct fsid_entry *fsid;
        char full_path[MAXPATHLEN];
        char link_path[MAXPATHLEN];
        char *volname;

        if (fsid_alias_exists(dev))
                return EEXIST;

        sprintf(full_path, "/dev/%s", dev);
        volname = fsid_volname_all(full_path);
        if (volname == NULL)
                return 0;

        printf("Volume name for %s is %s\n", dev, volname);
        fsid = malloc(sizeof(struct fsid_entry));
        if (fsid == NULL)
                return ENOMEM;
#if 1
        sprintf(link_path, "/dev/vol-by-name/%s", volname);

        fsid->dev_path = strdup(dev);
        fsid->link_path = strdup(link_path);
        if ((fsid->dev_path == NULL) || (fsid->link_path == NULL)) {
                free(fsid);
                return ENOMEM;
        }

        mkdir("/dev/vol-by-name", 0755);
        symlink(full_path, link_path);

        TAILQ_INSERT_TAIL(&fsid_list, fsid, link);
#endif

        return 0;
}

static int
fsid_check_remove_alias(const char *dev)
{
        struct fsid_entry *fsid, *fsid2;

        if (!fsid_alias_exists(dev))
                return 0;

        TAILQ_FOREACH_MUTABLE(fsid, &fsid_list, link, fsid2) {
                if (strcmp(fsid->dev_path, dev) != 0)
                        continue;

                TAILQ_REMOVE(&fsid_list, fsid, link);

                unlink(fsid->link_path);

                free(fsid->dev_path);
                free(fsid->link_path);
                free(fsid);
        }

        return 0;
}

static
void
usage(void)
{
        fprintf(stderr, "usage: fsid [-d]\n");
        exit(1);
}

int
main(int argc, char *argv[])
{
        struct udev *udev;
        struct udev_enumerate *udev_enum;
        struct udev_list_entry *udev_le, *udev_le_first;
        struct udev_monitor *udev_monitor;
        struct udev_device *udev_dev;
        int ch;
#if 0
        prop_dictionary_t *dict;
#endif
        int ret, daemon_flag = 0;
        const char *prop, *dev_path;

        while ((ch = getopt(argc, argv, "d")) != -1) {
                switch(ch) {
                case 'd':
                        daemon_flag = 1;
                        break;
                default:
                        usage();
                        /* NOT REACHED */
                }
        }
        argc -= optind;
        argv += optind;

        udev = udev_new();
        if (udev == NULL)
                err(1, "udev_new");

        udev_enum = udev_enumerate_new(udev);
        if (udev_enum == NULL)
                err(1, "udev_enumerate_new");

        ret = udev_enumerate_add_match_property(udev_enum, "subsystem", "disk");
        if (ret != 0)
                err(1, "udev_enumerate_add_match_property, out, ret=%d\n", ret);

        ret = udev_enumerate_add_match_property(udev_enum, "alias", "0");
        if (ret != 0)
                err(1, "udev_enumerate_add_match_property, out, ret=%d\n", ret);

        ret = udev_enumerate_add_nomatch_property(udev_enum, "disk-type", "memory");
        if (ret != 0)
                err(1, "udev_enumerate_add_match_property, out, ret=%d\n", ret);

        ret = udev_enumerate_add_nomatch_property(udev_enum, "disk-type", "floppy");

        ret = udev_enumerate_scan_devices(udev_enum);
        if (ret != 0)
                err(1, "udev_enumerate_scan_device ret = %d", ret);

        udev_le_first = udev_enumerate_get_list_entry(udev_enum);
        if (udev_le_first == NULL)
                err(1, "udev_enumerate_get_list_entry error");

        udev_list_entry_foreach(udev_le, udev_le_first) {
                udev_dev = udev_list_entry_get_device(udev_le);
                dev_path = udev_device_get_devnode(udev_dev);
#if 0
                dict = udev_device_get_dictionary(udev_dev);
                printf("xml of new device: %s\n", prop_dictionary_externalize(dict));
#endif
                fsid_check_create_alias(dev_path);
        }

        udev_enumerate_unref(udev_enum);

        if (daemon_flag) {
#if 0
                if (daemon(0, 0) == -1)
                        err(1, "daemon");
#endif

                udev_monitor = udev_monitor_new(udev);
                ret = udev_monitor_filter_add_match_property(udev_monitor, "subsystem", "disk");
                if (ret != 0)
                        err(1, "udev_monitor_filter_add_match_property, out, ret=%d\n", ret);

                ret = udev_monitor_filter_add_match_property(udev_monitor, "alias", "0");
                if (ret != 0)
                        err(1, "udev_monitor_filter_add_match_property, out, ret=%d\n", ret);

                ret = udev_monitor_filter_add_nomatch_property(udev_monitor, "disk-type", "memory");
                if (ret != 0)
                        err(1, "udev_monitor_filter_add_nomatch_property, out, ret=%d\n", ret);

                ret = udev_monitor_enable_receiving(udev_monitor);
                if (ret != 0)
                        err(1, "udev_monitor_enable_receiving ret = %d", ret);

                while ((udev_dev = udev_monitor_receive_device(udev_monitor))) {
                        if (udev_dev == NULL)
                                err(1, "udev_monitor_receive_device failed");

                        dev_path = udev_device_get_devnode(udev_dev);
                        prop = udev_device_get_action(udev_dev);

                        if (strcmp(prop, "attach") == 0)
                                fsid_check_create_alias(dev_path);
                        else if (strcmp(prop, "detach") == 0)
                                fsid_check_remove_alias(dev_path);
                }

                udev_monitor_unref(udev_monitor);
        }

        udev_unref(udev);

        return 0;
}