/* Coldboot walks parts of the /sys tree and pokes the uevent files
** to cause the kernel to regenerate device add events that happened
** before init's device manager was started
**
** We drain any pending events from the netlink socket every time
** we poke another uevent file to make sure we don't overrun the
** socket's buffer.
*/

static void do_coldboot(DIR *d)
{
    struct dirent *de;
    int dfd, fd;

    dfd = dirfd(d);

    fd = openat(dfd, "uevent", O_WRONLY);
    if(fd >= 0) {
        write(fd, "add\n", 4);
        close(fd);
        handle_device_fd();
    }

    while((de = readdir(d))) {
        DIR *d2;

        if(de->d_type != DT_DIR || de->d_name[0] == '.')
            continue;

        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
        if(fd < 0)
            continue;

        d2 = fdopendir(fd);
        if(d2 == 0)
            close(fd);
        else {
            do_coldboot(d2);
            closedir(d2);
        }
    }
}

static void coldboot(const char *path)
{
    DIR *d = opendir(path);
    if(d) {
        do_coldboot(d);
        closedir(d);
    }
}

void device_init(void)
{
    suseconds_t t0, t1;
    struct stat info;
    int fd;

    sehandle = NULL;
    if (is_selinux_enabled() > 0) {
        sehandle = selinux_android_file_context_handle();
        selinux_status_open(true);
    }

    /* is 256K enough? udev uses 16MB! */
    device_fd = uevent_open_socket(256*1024, true);
    if(device_fd < 0)
        return;

    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
    fcntl(device_fd, F_SETFL, O_NONBLOCK);

    if (stat(coldboot_done, &info) < 0) {
        t0 = get_usecs();
        coldboot("/sys/class");
        coldboot("/sys/block");
        coldboot("/sys/devices");
        t1 = get_usecs();
        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
        close(fd);
        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
    } else {
        log_event_print("skipping coldboot, already done\n");
    }
}