basic.c

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

int main(int argc, char **argv)
{
	char *file;
	char *host;

	if(argc < 3) {
		printf("%s file host\n\tsends file to host if you have access to it\n", argv[0]);
		exit(1);
	}

	file = argv[1];
	host = argv[2];

	if(access(argv[1], R_OK) == 0) {
		int fd;
		int ffd;
		int rc;
		struct sockaddr_in sin;
		char buffer[4096];

		printf("Connecting to %s:18211 .. ", host); fflush(stdout);

		fd = socket(AF_INET, SOCK_STREAM, 0);

		memset(&sin, 0, sizeof(struct sockaddr_in));
		sin.sin_family = AF_INET;
		sin.sin_addr.s_addr = inet_addr(host);
		sin.sin_port = htons(18211);

		if(connect(fd, (void *)&sin, sizeof(struct sockaddr_in)) == -1) {
			printf("Unable to connect to host %s\n", host);
			exit(EXIT_FAILURE);
		}

#define HITHERE ".oO Oo.\n"
		if(write(fd, HITHERE, strlen(HITHERE)) == -1) {
			printf("Unable to write banner to host %s\n", host);
			exit(EXIT_FAILURE);
		}
#undef HITHERE

		printf("Connected!\nSending file .. "); fflush(stdout);

		ffd = open(file, O_RDONLY);
		if(ffd == -1) {
			printf("Damn. Unable to open file\n");
			exit(EXIT_FAILURE);
		}

		rc = read(ffd, buffer, sizeof(buffer));
		if(rc == -1) {
			printf("Unable to read from file: %s\n", strerror(errno));
			exit(EXIT_FAILURE);
		}

		write(fd, buffer, rc);

		printf("wrote file!\n");

	} else {
		printf("You don't have access to %s\n", file);
	}
}