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

int	redirect_stdio_to_socket(char	*target)
{
	int	fd = connect_socket(target);

	if(fd<0)return -1;
	close(0);
	close(1);
	dup2(fd, 0);
	dup2(fd, 1);
	return 0;
}

struct in_addr	lookup_host(char	*host)
{
	struct in_addr	addr;
	struct hostent	*he;

	if(inet_aton(host, &addr))return addr;
	he = gethostbyname(host);
	if(!he)
	{
		fprintf(stderr, "unable to find host `%s'\n", host);
		exit(-1);
	}

	if(he->h_addrtype != AF_INET)
	{
		fprintf(stderr, "`%s' is not an internet host\n", host);
		exit(-1);
	}

	if(he->h_length != sizeof(struct in_addr))
	{
		fprintf(stderr, "`%s' address is not an IPv4 address\n", host);
		exit(-1);
	}

	addr = *(struct in_addr*)he->h_addr;
	return addr;
}

struct sockaddr_in	make_address(char	*host, int	port)
{
	struct sockaddr_in	addr;

	addr.sin_family = AF_INET;
	addr.sin_port = htons((short)port);
	addr.sin_addr.s_addr = (lookup_host(host).s_addr);

	//printf("target %s : %d\n", inet_ntoa(addr.sin_addr), port);
	return addr;
}

int	connect_socket(char	*target)
{
	char			*host, *portstr;
	int			port, fd;
	struct sockaddr_in	addr;

	host = target;
	portstr = strchr(target, ':');
	if(!portstr)
	{
		// should we have a default port?
		invalid:
		fprintf(stderr, "invalid host/port specification `%s'\n", target);
		fprintf(stderr, "  should be of the form: host:port\n");
		exit(-1);
	}
	port = atoi(portstr+1);
	if(port==0)goto invalid;
	*portstr=0;

	fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if(fd<0)
	{
		perror("socket");
		exit(-1);
	}
	addr = make_address(host, port);
	*portstr=':';

	if(connect(fd, (struct sockaddr*)&addr, sizeof(addr)))
	{
		perror("connect");
		close(fd);
		return -1;
	}
	return fd;
}