/*
 * rexec: remote exec
 */

/*
 * Copyright (c) 2006 Andreas Jaggi <andreas.jaggi@waterwave.ch>
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>

#include "rexec.h"

const char usagemsg[] =
	"usage: rexec -i [IP] -c [command] <args>\n"
	"\n"
	"options:\n"
	"    -i IP         connect to host with address IP\n"
	"    -c command    execute command on host\n"
	" also: rexec -v    show version\n"
	"       rexec -h    display this help\n"
	"       rexec -l    display (BSD) license\n"
	;

const char versionmsg[] = "rexec 0.2\n";

void usage(void);
void version(void);

int main ( int argc, char* argv[] ) {
	int localargsparsed = 0;
	int i;
	int sock;
	int tmp;
	char buff;
	char *command = NULL;
	in_addr_t remote_addr = 0;
	struct sockaddr_in *remote_host_addr = NULL;

	while ( !localargsparsed && (tmp = getopt(argc, argv, "i:c:hlv")) != -1 ) {
		switch ( tmp ) {
			case 'h':
				usage();
				exit(0);
			case 'l':
				license();
				exit(0);
			case 'v':
				version();
				exit(0);
			case 'i':
				remote_addr = inet_addr(optarg);
				if ( command != NULL ) {
					localargsparsed = 1;
				}
				break;
			case 'c':
				command = optarg;
				if ( remote_addr != 0 ) {
					localargsparsed = 1;
				}
				break;
		}
	}

	if ( (remote_addr == 0) || (command == NULL) ) {
		usage();
		exit(-1);
	}

	remote_host_addr = alloca(sizeof(struct sockaddr_in));
	remote_host_addr->sin_family = AF_INET;
	remote_host_addr->sin_addr.s_addr = remote_addr;
	remote_host_addr->sin_port = REXEC_PORT;

	sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if ( sock < 0 ) {
		showerror("socket");
		exit(-1);
	}

	if ( connect(sock, (struct sockaddr*)remote_host_addr, sizeof(struct sockaddr_in)) < 0 ) {
		showerror("connect");
		exit(-1);
	}

	/* send command with args and a final \n */
	write(sock, command, strlen(command)+1);
	for ( i = optind; i < argc; i++ ) {
		write(sock, argv[i], strlen(argv[i])+1);
	}
	write(sock, "\n", 1);


	if ( fork() == 0 ) {
		while ( tmp > -1 ) {
			if ( (tmp = read(sock, &buff, 1)) == 1 ) {
				write(1, &buff, 1);
			} else {
				usleep(200000);
			}
		}
	} else {
		while ( tmp > -1 ) {
			if ( (tmp = read(1, &buff, 1)) == 1 ) {
				write(sock, &buff, 1);
			} else {
				usleep(200000);
			}
		}
	}


	if ( shutdown(sock, SHUT_RDWR) < 0 ) {
		showerror("shutdown");
		exit(-1);
	}

	if ( close(sock) < 0 ) {
		showerror("close");
		exit(-1);
	}

	while ( wait(&tmp) > 0 ) { }

	exit(0);
}

void usage(void) {
	write(1, usagemsg, strlen(usagemsg));
}

void version(void) {
	write(1, versionmsg, strlen(versionmsg));
}