/* nl2mdev - netlink wrapper for busybox's mdev
 * gcc -std=c99 -pedantic -Wall -O2 nl2mdev.c -o nl2mdev */

#define _XOPEN_SOURCE 500

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>

#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#include <linux/types.h>
#include <linux/netlink.h>


void die(char *s)
{
	write(2,s,strlen(s));
	exit(1);
}

int main(int argc, char *argv[])
{
	struct sockaddr_nl nls;
	struct pollfd pfd;
	char buf[512];

	signal(SIGCHLD, SIG_IGN);

	// Open hotplug event netlink socket

	memset(&nls,0,sizeof(struct sockaddr_nl));
	nls.nl_family = AF_NETLINK;
	nls.nl_pid = getpid();
	nls.nl_groups = -1;

	pfd.events = POLLIN;
	pfd.fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
	if (pfd.fd==-1)
		die("Not root\n");

	// Listen to netlink socket

	if (bind(pfd.fd, (void *)&nls, sizeof(struct sockaddr_nl)))
		die("Bind failed\n");
	while (-1!=poll(&pfd, 1, -1)) {
		int i, len = recv(pfd.fd, buf, sizeof(buf), MSG_DONTWAIT);
		if (len == -1) die("recv\n");


		
		if (!fork())
		{
			unsigned int count = 0;
			char **env = calloc(9, sizeof(char *));
			i = 0;
			while (i<len) {
				env[count++] = (char *) strdup(buf+i);
				i += strlen(buf+i)+1;
			}
			env[count] = (char *) NULL;
			
			execle("/usr/bin/mdev", "/usr/bin/mdev", (char *) NULL, env);
			
			exit(0);
		}
	}
	die("poll\n");

	// Dear gcc: shut up.
	return 0;
}