/* stolen from https://john-millikin.com/running-sunos-4-in-qemu-sparc */
#include <arpa/inet.h>
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

int split_server_address(server_address, server_ip, server_port)
	char *server_address;
	unsigned long *server_ip;
	unsigned short *server_port;
{
	char *port_str, *port_extra;
	long port_raw;

	port_str = strchr(server_address, ':');
	if (port_str == NULL) {
		return -1;
	}
	*(port_str++) = 0;

	*server_ip = inet_addr(server_address);
	if (*server_ip == -1) {
		return -1;
	}

	port_raw = strtol(port_str, &port_extra, 10);
	if (port_raw < 1 || port_raw > 65535) {
		return -1;
	}
	if (*port_extra != 0) {
		return -1;
	}
	*server_port = port_raw;

	return 0;
}

int recv_file(server_ip, server_port, output_path)
	unsigned long server_ip;
	unsigned short server_port;
	char *output_path;
{
	int socket_fd, output_fd;
	struct sockaddr_in server;
	char buffer[2048];

	socket_fd = socket(AF_INET, SOCK_STREAM, 0);
	if (socket_fd == -1) {
		return -1;
	}

	memset(&server, 0, sizeof server);
	server.sin_family = AF_INET;
	server.sin_addr.s_addr = server_ip;
	server.sin_port = htons(server_port);

	if (connect(socket_fd, (struct sockaddr*)&server, sizeof server) == -1) {
		return -1;
	}

	output_fd = open(output_path, O_WRONLY | O_CREAT, 0600);
	if (output_fd == -1) {
		return -1;
	}

	while (1) {
		int n = read(socket_fd, buffer, sizeof buffer);
		if (n == -1) {
			close(output_fd);
			return -1;
		}
		if (n == 0) {
			return close(output_fd);
		}
		write(output_fd, buffer, n);
	}
}

int main(argc, argv)
	int argc;
	char **argv;
{
	unsigned long server_ip;
	unsigned short server_port;

	if (argc < 3) {
		fprintf(stderr, "Usage: %s <server_address> <output_path>\n", argv[0]);
		return 1;
	}

	if (split_server_address(argv[1], &server_ip, &server_port) == -1) {
		fprintf(stderr, "Invalid server address \"%s\"\n", argv[1]);
		return 1;
	}

	if (recv_file(server_ip, server_port, argv[2]) == -1) {
		perror("Error receiving file");
		return 1;
	}

	return 0;
}