/*
 * httphead - show http header of a website
 */

/*
 * 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 <unistd.h>
#include <stdlib.h>
#include <netdb.h>

#include <errno.h>
#include <string.h>

const char usagemsg[] =
	"usage: httphead [-r] [-q] [-p port] [-s host] [-d path] [-s host] URL\n"
	"\n"
	"options:\n"
	"    -p port    use this port instead of 80\n"
	"    -s host    use this host instead of the one specified in the URL\n"
	"    -d path    use this path instead of the one specified in the URL\n"
	"    -r         show sent request\n"
	"    -q         show only the recieved status code\n"
	" also: -v    show version\n"
	"       -h    display this help\n"
	"       -l    display (BSD) license\n"
	;

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

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

#define HH_BUFFSIZE 512

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

void showerror ( char* type );

void crlf ( int s );

char* gethost ( char* url );
char* getpath ( char* url );
char* getstatuscode ( char* response );

int main ( int argc, char* argv[] ) {

	int tmp;
	char* hend = NULL;
	char buff[HH_BUFFSIZE+1];

	char* url = NULL;

	char* host = NULL;
	char* path = NULL;
	int port = 80;

	int showrequest = 0;
	int statuscodeonly = 0;
	char* statuscode = NULL;

	struct hostent *remote_hostent = NULL;
	struct sockaddr_in *remote_host_addr = NULL;

	int sock;

	while ( (tmp = getopt(argc, argv, "qrd:s:p:hlv")) != -1 ) {
		switch ( tmp ) {
			case 'h':
				usage();
				exit(0);
			case 'l':
				license();
				exit(0);
			case 'v':
				version();
				exit(0);
			case 'p':
				port = atoi(optarg);
				break;
			case 's':
				host = optarg;
				break;
			case 'd':
				path = optarg;
				break;
			case 'q':
				statuscodeonly = 1;
				break;
			case 'r':
				showrequest = 1;
				break;
		}
	}

	if ( optind >= argc ) {
		usage();
		exit(0);
	}

	url = argv[optind];

	if ( path == NULL ) {
		path = getpath(url);
	}

	if ( host == NULL ) {
		host = gethost(url);
	}

	remote_hostent = gethostbyname(host);

	if ( remote_hostent == NULL ) {
		herror(NULL);
		exit(-1);
	}

	remote_host_addr = alloca(sizeof(struct sockaddr_in));
	remote_host_addr->sin_family = AF_INET;
	remote_host_addr->sin_addr = *((struct in_addr*) remote_hostent->h_addr);
	remote_host_addr->sin_port = port;

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

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


	/* main */

	if ( showrequest ) {
		write(1, "GET ", 4);
		write(1, path, strlen(path));
		write(1, " HTTP/1.0", 9);
		crlf(1);
		write(1, "Host: ", 6);
		write(1, host, strlen(host));

		crlf(1);
		crlf(1);

		write(1, "Response:\n\n", 12);
	} 

	write(sock, "GET ", 4);
	write(sock, path, strlen(path));
	write(sock, " HTTP/1.0", 9);
	crlf(sock);
	write(sock, "Host: ", 6);
	write(sock, host, strlen(host));

	crlf(sock);
	crlf(sock);

	while ( (tmp = recv(sock, buff, HH_BUFFSIZE, 0)) > 0 ) {
		buff[tmp] = '\0';

		if ( (hend = strstr(buff, "\x0D\x0A\x0D\x0A")) != NULL) {
			tmp = hend-buff;
			*hend = '\n';
			*(hend+1) = '\0';
		}

		if ( statuscodeonly ) {
			if ( (statuscode = getstatuscode(buff)) != NULL ) {
				write(1, statuscode, 3);
				write(1, "\n", 1);
				break;
			}
		} else {
			write(1, buff, tmp);
		}

		if ( hend != NULL ) {
			break;
		}
	}

	if ( shutdown(sock, 2) == -1 ) {
		showerror("shutdown");
		exit(-1);
	}

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

	exit(0);
}

char* _gethoststart ( char* url ) {
	char* s = NULL;

	s = strstr(url, "http://");
	if ( s == NULL ) {
		s = strstr(url, "https://");
		if ( s == NULL ) {
			s = url; // assume that there is no http[s]:// prefix
		} else {
			s += 8;
		}
	} else {
		s += 7;
	}

	if ( s >= url + strlen(url) ) {
		return url;
	}

	return s;
}

int _gethostlen ( char* s ) {
	int e = 0;

	while ( *(s+e) != '/' && *(s+e) != '?' && *(s+e) != '\0' ) {
		e++;
	}

	return e;
}

char* getstatuscode ( char* s ) {
	char* htp = NULL;

	if ( (htp = strstr(s, "HTTP/")) != NULL ) {
		while ( *htp != '\0' && *htp != ' ' ) {
			htp++;
		}

		while ( *htp == ' ' ) {
			htp++;
		}

		if ( *htp == '\0' ) {
			htp = NULL;
		}
	}

	return htp;
}

char* getpath ( char* url ) {
	char* s = NULL;
	int e;

	s = _gethoststart(url);

	e = _gethostlen(s);

	s += e;

	if ( s >= url+strlen(url) ) {
		s = (char*)malloc(2*sizeof(char));
		*s = '/';
		*(s+1) = '\0';
	}

	return s;
}

char* gethost ( char* url ) {
	char* s = NULL;
	char* r = NULL;
	int e = 0;

	s = _gethoststart(url);

	e = _gethostlen(s);

	if ( e == 0 ) {
		return NULL;
	}

	r = (char*)malloc(sizeof(char)*(e+1));

	memcpy(r, s, e);

	r[e+1] = '\0';

	return r;
}

void crlf ( int s ) {
	write(s, "\x0D\x0A", 2);
}

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

void license ( ) {
	write(1, licensemsg, strlen(licensemsg));
}

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

void showerror ( char* type ) {
	char* errstr = strerror(errno);
	write(2, type, strlen(type));
	write(2, ": ", 2);
	write(2, errstr, strlen(errstr));
	write(2, "\n", 1);
}