/*
 * Copyright 2011 Stefan Lankes
 *                     Chair for Operating Systems, RWTH Aachen University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>

#define PORT	4711

int main(int argc, char* argv[])
{
	int sockd, sockd2;
	unsigned int addrlen;
	struct sockaddr_in my_name, peer_name;
	int status;
	pid_t pid;

	/* create a socket */
	sockd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockd == -1)
	{
		perror("Socket creation error");
		exit(1);
	}

	memset(&my_name, 0x00, sizeof(my_name));
	/* server address  */
	my_name.sin_family = AF_INET;
	my_name.sin_addr.s_addr = INADDR_ANY;
	my_name.sin_port = htons(PORT);

	status = bind(sockd, (struct sockaddr*)&my_name, sizeof(my_name));
	if (status == -1)
	{
		perror("Binding error");
		exit(1);
	}

	status = listen(sockd, 5);
	if (status == -1)
	{
		perror("Listening error");
		exit(1);
	}

	while(1)
	{
		/* wait for a connection */
		addrlen = sizeof(peer_name);
		sockd2 = accept(sockd, (struct sockaddr*)&peer_name, &addrlen);
		if (sockd2 == -1)
		{
			perror("Wrong connection");
			exit(1);
		}


		pid = fork();
		if (pid == 0) { // child
			char* newargs[] = {"/bin/mshell", NULL};
			char* newenv[] = {"USER=root", "PATH=/bin:/sbin:/usr/bin", "PWD=/", "TEMP=/tmp", NULL};
			
			// set stdout, stdin and stderr to the socket descriptor
			dup2(sockd2, STDIN_FILENO);
			dup2(sockd2, STDOUT_FILENO);
			dup2(sockd2, STDERR_FILENO);

			close(sockd2);
			execve("/bin/mshell", newargs, newenv);
			return errno;
		}
		close(sockd2);
	}

	return 0;
}