main.c

经典的unix下telnet的c代码

/*	$OpenBSD: main.c,v 1.15 2003/12/28 21:53:01 otto Exp $	*/
/*	$NetBSD: main.c,v 1.5 1996/02/28 21:04:05 thorpej Exp $	*/

/*
 * Copyright (c) 1988, 1990, 1993
 *	The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1988, 1990, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#include "telnet_locl.h"

/* These values need to be the same as defined in libtelnet/kerberos5.c */
/* Either define them in both places, or put in some common header file. */
#define OPTS_FORWARD_CREDS	0x00000002
#define OPTS_FORWARDABLE_CREDS	0x00000001

#ifdef KRB5
#define FORWARD
/* XXX ugly hack to setup dns-proxy stuff */
#define Authenticator asn1_Authenticator
#include <kerberosV/krb5.h>
#endif

#ifdef KRB4
#include <kerberosIV/krb.h>
#endif

#ifdef FORWARD
int forward_flags;
static int default_forward=0;
#endif

int family = AF_UNSPEC;

/*
 * Initialize variables.
 */
    void
tninit()
{
    init_terminal();

    init_network();

    init_telnet();

    init_sys();

#if defined(TN3270)
    init_3270();
#endif
}

	void
usage()
{
	fprintf(stderr, "Usage: %s %s%s%s%s\n",
	    prompt,
#ifdef	AUTHENTICATION
	    "[-4] [-6] [-8] [-E] [-K] [-L] [-S tos] [-X atype] [-a] [-c] [-d]",
	    "\n\t[-e char] [-k realm] [-l user] [-f/-F] [-n tracefile] [-b hostalias] ",
#else
	    "[-4] [-6] [-8] [-E] [-L] [-S tos] [-a] [-c] [-d] [-e char]",
	    "\n\t[-l user][-n tracefile] [-b hostalias] ",
#endif
	    "\n\t"
#if defined(TN3270) && defined(unix)
# ifdef AUTHENTICATION
	    "[-noasynch] [-noasynctty] [-noasyncnet] [-r] [-t transcom]\n\t",
# else
	    "[-noasynch] [-noasynctty] [-noasyncnet] [-r] [-t transcom]\n\t",
# endif
#else
	    "[-r] ",
#endif
#ifdef ENCRYPTION
	    "[-x] "
#endif
	    "[host-name [port]]");
	exit(1);
}


#ifdef KRB5
static void
krb5_init(void)
{
    krb5_context context;
    krb5_error_code ret;

    ret = krb5_init_context(&context);
    if (ret)
	return;

#if defined(AUTHENTICATION) && defined(KRB5) && defined(FORWARD)
    if (krb5_config_get_bool (context, NULL,
         "libdefaults", "forward", NULL)) {
           forward_flags |= OPTS_FORWARD_CREDS;
           default_forward=1;
    }
    if (krb5_config_get_bool (context, NULL,
         "libdefaults", "forwardable", NULL)) {
           forward_flags |= OPTS_FORWARDABLE_CREDS;
           default_forward=1;
    }
#endif
#ifdef  ENCRYPTION
    if (krb5_config_get_bool (context, NULL,
        "libdefaults", "encrypt", NULL)) {
          encrypt_auto(1);
          decrypt_auto(1); 
	  wantencryption = 1;
          EncryptVerbose(1);
        }
#endif

    krb5_free_context(context);
}
#endif

/*
 * main.  Parse arguments, invoke the protocol or command parser.
 */

	int
main(argc, argv)
	int argc;
	char *argv[];
{
	extern char *optarg;
	extern int optind;
	int ch;
	char *user, *alias;
#ifdef	FORWARD
	extern int forward_flags;
#endif	/* FORWARD */

#ifdef KRB5
	krb5_init();
#endif

	tninit();		/* Clear out things */

	TerminalSaveState();

	if ((prompt = strrchr(argv[0], '/')))
		++prompt;
	else
		prompt = argv[0];

	user = alias = NULL;

	rlogin = (strncmp(prompt, "rlog", 4) == 0) ? '~' : _POSIX_VDISABLE;

	/* 
	 * if AUTHENTICATION and ENCRYPTION is set autologin will be
	 * set to true after the getopt switch; unless the -K option is
	 * passed 
	 */
	autologin = -1;

	while ((ch = getopt(argc, argv, "4678DEKLS:X:ab:cde:fFk:l:n:rt:x"))
	    != -1) {
		switch(ch) {
		case '4':
			family = AF_INET;
			break;
		case '6':
			family = AF_INET6;
			break;
		case '8':
			eight = 3;	/* binary output and input */
			break;
		case '7':
			eight = 0;
			break;
		case 'D': {
			/* sometimes we don't want a mangled display */
			char *p;
			if((p = getenv("DISPLAY")))
				env_define("DISPLAY", (unsigned char*)p);
			break;
		}

		case 'E':
			rlogin = escape = _POSIX_VDISABLE;
			break;
		case 'K':
#ifdef	AUTHENTICATION
			autologin = 0;
#endif
			break;
		case 'L':
			eight |= 2;	/* binary output only */
			break;
		case 'S':
		    {
#ifdef	HAS_GETTOS
			extern int tos;

			if ((tos = parsetos(optarg, "tcp")) < 0)
				fprintf(stderr, "%s%s%s%s\n",
					prompt, ": Bad TOS argument '",
					optarg,
					"; will try to use default TOS");
#else
			fprintf(stderr,
			   "%s: Warning: -S ignored, no parsetos() support.\n",
								prompt);
#endif
		    }
			break;
		case 'X':
#ifdef	AUTHENTICATION
			auth_disable_name(optarg);
#endif
			break;
		case 'a':
			autologin = 1;
			break;
		case 'c':
			skiprc = 1;
			break;
		case 'd':
			debug = 1;
			break;
		case 'e':
			set_escape_char(optarg);
			break;
		case 'f':
#if defined(AUTHENTICATION) && defined(KRB5) && defined(FORWARD)
			if ((forward_flags & OPTS_FORWARD_CREDS) &&
			    !default_forward) {
			    fprintf(stderr,
				    "%s: Only one of -f and -F allowed.\n",
				    prompt);
			    usage();
			}
			forward_flags |= OPTS_FORWARD_CREDS;
#else
			fprintf(stderr,
			 "%s: Warning: -f ignored, no Kerberos V5 support.\n",
				prompt);
#endif
			break;
		case 'F':
#if defined(AUTHENTICATION) && defined(KRB5) && defined(FORWARD)
			if ((forward_flags & OPTS_FORWARD_CREDS) &&
			    !default_forward) {
			    fprintf(stderr,
				    "%s: Only one of -f and -F allowed.\n",
				    prompt);
			    usage();
			}
			forward_flags |= OPTS_FORWARD_CREDS;
			forward_flags |= OPTS_FORWARDABLE_CREDS;
#else
			fprintf(stderr,
			 "%s: Warning: -F ignored, no Kerberos V5 support.\n",
				prompt);
#endif
			break;
		case 'k':
#if defined(AUTHENTICATION) && defined(KRB4)
		    {
			extern char *dest_realm, dst_realm_buf[];
			extern int dst_realm_sz;
			dest_realm = dst_realm_buf;
			(void)strncpy(dest_realm, optarg, dst_realm_sz);
		    }
#else
			fprintf(stderr,
			   "%s: Warning: -k ignored, no Kerberos V4 support.\n",
								prompt);
#endif
			break;
		case 'l':
			autologin = -1;
			user = optarg;
			break;
		case 'b':
			alias = optarg;
			break;
		case 'n':
#if defined(TN3270) && defined(unix)
			/* distinguish between "-n oasynch" and "-noasynch" */
			if (argv[optind - 1][0] == '-' && argv[optind - 1][1]
			    == 'n' && argv[optind - 1][2] == 'o') {
				if (!strcmp(optarg, "oasynch")) {
					noasynchtty = 1;
					noasynchnet = 1;
				} else if (!strcmp(optarg, "oasynchtty"))
					noasynchtty = 1;
				else if (!strcmp(optarg, "oasynchnet"))
					noasynchnet = 1;
			} else
#endif	/* defined(TN3270) && defined(unix) */
				SetNetTrace(optarg);
			break;
		case 'r':
			rlogin = '~';
			break;
		case 't':
#if defined(TN3270) && defined(unix)
			(void)strlcpy(tline, optarg, sizeof tline);
			transcom = tline;
#else
			fprintf(stderr,
			   "%s: Warning: -t ignored, no TN3270 support.\n",
								prompt);
#endif
			break;
		case 'x':
#ifdef ENCRYPTION
			encrypt_auto(1);
			decrypt_auto(1);
			wantencryption = 1;
			EncryptVerbose(1);
#else
			fprintf(stderr,
			    "%s: Warning: -x ignored, no ENCRYPT support.\n",
								prompt);
#endif
			break;
		case '?':
		default:
			usage();
			/* NOTREACHED */
		}
	}

	if (autologin == -1) {
#if defined(AUTHENTICATION)
		if(check_krb4_tickets() || check_krb5_tickets())
			autologin = 1;
#endif
#if defined(ENCRYPTION)
		encrypt_auto(1);
		decrypt_auto(1);
#endif
	}

	if (autologin == -1)
		autologin = (rlogin == _POSIX_VDISABLE) ? 0 : 1;

	argc -= optind;
	argv += optind;

	if (argc) {
		char *args[7], **argp = args;

		if (argc > 2)
			usage();
		*argp++ = prompt;
		if (user) {
			*argp++ = "-l";
			*argp++ = user;
		}
		if (alias) {
			*argp++ = "-b";
			*argp++ = alias;
		}
		*argp++ = argv[0];		/* host */
		if (argc > 1)
			*argp++ = argv[1];	/* port */
		*argp = 0;

		if (setjmp(toplevel) != 0)
			Exit(0);
		if (tn(argp - args, args) == 1)
			return (0);
		else
			return (1);
	}
	(void)setjmp(toplevel);
	for (;;) {
#ifdef TN3270
		if (shell_active)
			shell_continue();
		else
#endif
			command(1, 0, 0);
	}
	return 0;
}