host.c

早期freebsd实现

#ifdef DEBUG
#define assert(condition)\
{\
	if (!(condition))\
	{\
		(void) fprintf(stderr, "assertion botch: ");\
		(void) fprintf(stderr, "%s(%d): ", __FILE__, __LINE__);\
		(void) fprintf(stderr, "%s\n", "condition");\
		exit(EX_SOFTWARE);\
	}\
}
#else
#define assert(condition)
#endif

/*
** MAIN -- Start of program host
** -----------------------------
**
**	Exits:
**		EX_OK		Operation successfully completed
**		EX_UNAVAILABLE	Could not obtain requested information
**		EX_CANTCREAT	Could not create specified logfile
**		EX_NOINPUT	No input arguments were found
**		EX_NOHOST	Could not lookup explicit server
**		EX_OSERR	Could not obtain resources
**		EX_USAGE	Improper parameter/option specified
**		EX_SOFTWARE	Assertion botch in DEBUG mode
*/

int
main(argc, argv)
input int argc;
input char *argv[];
{
	register char *option;
	res_state_t new_res;		/* new resolver database */
	int result;			/* result status of action taken */
	char *program;			/* name that host was called with */
	char *servername = NULL;	/* name of explicit server */
	bool extended = FALSE;		/* accept extended argument syntax */

	assert(sizeof(u_int) == 4);	/* paranoid */
	assert(sizeof(u_short) == 2);	/* paranoid */
	assert(sizeof(ipaddr_t) == 4);	/* but this is critical */

/*
 * Synchronize stdout and stderr in case output is redirected.
 */
	linebufmode(stdout);

/*
 * Initialize resolver. See show_res() for details.
 * Pickup current values and set new defaults.
 * Query for optional server is also done with new defaults.
 * Old defaults are (RES_RECURSE | RES_DEFNAMES | RES_DNSRCH)
 */
	(void) res_init();

	/* we handle default domains ourselves, thank you */
	_res.options |=  RES_DEFNAMES;
	_res.options &= ~RES_DNSRCH;

	_res.options |=  RES_RECURSE;
	_res.options &= ~RES_DEBUG;
	_res.options &= ~RES_USEVC;

	_res.retry = 2;		/* number  of retries, default = 4 */
	_res.retrans = 5;	/* timeout in seconds, default = 5 or 6 */

	/* save new defaults */
	new_res = _res;

/*
 * Check if host was called with a different name.
 * Interpolate default options and parameters.
 */
	option = getenv("HOST_DEFAULTS");
	if (option != NULL)
	{
		set_defaults(option, argc, argv);
		argc = optargc; argv = optargv;
	}

	program = rindex(argv[0], '/');
	if (program++ == NULL)
		program = argv[0];

	/* check for resource record names */
	querytype = parse_type(program);
	if (querytype < 0)
		querytype = T_NONE;

	/* check for zone listing abbreviation */
	if (sameword(program, "zone"))
		listmode = TRUE;

/*
 * Scan command line options and flags.
 */
	while (argc > 1 && argv[1][0] == '-')
	{
	    for (option = &argv[1][1]; *option != '\0'; option++)
	    {
		switch (*option)
		{
		    case 'w' :
			waitmode = TRUE;
			new_res.retry = 2;
			new_res.retrans = 5;
			break;

		    case 's' :
			if (argv[2] == NULL || argv[2][0] == '-')
				fatal("Missing timeout value");
			new_res.retry = 2;
			new_res.retrans = atoi(argv[2]);
			if (new_res.retrans <= 0)
				fatal("Invalid timeout value %s", argv[2]);
			argv++; argc--;
			break;

		    case 'r' :
			new_res.options &= ~RES_RECURSE;
			break;

		    case 'B' :
			bindcompat = TRUE;
			/* fall through */

		    case 'R' :
			new_res.options |= RES_DNSRCH;
			break;

		    case 'u' :
			new_res.options |= RES_USEVC;
			break;

		    case 'd' :
			new_res.options |= RES_DEBUG;
			debug++;		/* increment debugging level */
			break;

		    case 'v' :
			verbose++;		/* increment verbosity level */
			break;

		    case 'q' :
			quiet = TRUE;
			break;

		    case 'i' :
			reverse = TRUE;
			break;

		    case 'p' :
			primary = TRUE;
			break;

		    case 'o' :
			suppress = TRUE;
			break;

		    case 'e' :
			exclusive = TRUE;
			break;

		    case 'S' :
			statistics = TRUE;
			break;

		    case 'T' :
			ttlprint = TRUE;
			break;

		    case 'A' :
			addrmode = TRUE;
			break;

		    case 'D':
		    case 'E':
		    case 'G':
			if (*option == 'D')
				duplmode = TRUE;
			if (*option == 'E')
				extrmode = TRUE;
			if (*option == 'G')
				gatemode = TRUE;
			/* fall through */

		    case 'H' :
			hostmode = TRUE;
			listmode = TRUE;
			if (querytype == T_NONE)
				querytype = -1;	/* suppress zone data output */
			break;

		    case 'C' :
			checkmode = TRUE;
			listmode = TRUE;
			if (querytype == T_NONE)
				querytype = -1;	/* suppress zone data output */
			break;

		    case 'M' :
			mxrecmode = TRUE;
			listmode = TRUE;
			if (querytype == T_NONE)
				querytype = -1;	/* suppress zone data output */
			break;

		    case 'l' :
			listmode = TRUE;
			break;

		    case 'L' :
			if (argv[2] == NULL || argv[2][0] == '-')
				fatal("Missing recursion level");
			recursive = atoi(argv[2]);
			if (recursive <= 0)
				fatal("Invalid recursion level %s", argv[2]);
			argv++; argc--;
			break;

		    case 'F' :
			logexchange = TRUE;
			/* fall through */

		    case 'f' :
			if (argv[2] == NULL || argv[2][0] == '-')
				fatal("Missing logfile name");
			logfilename = argv[2];
			argv++; argc--;
			break;

		    case 'I' :
			if (argv[2] == NULL || argv[2][0] == '-')
				fatal("Missing allowed chars");
			illegal = argv[2];
			argv++; argc--;
			break;

		    case 'c' :
			if (argv[2] == NULL || argv[2][0] == '-')
				fatal("Missing query class");
			queryclass = parse_class(argv[2]);
			if (queryclass < 0)
				fatal("Invalid query class %s", argv[2]);
			argv++; argc--;
			break;

		    case 't' :
			if (argv[2] == NULL || argv[2][0] == '-')
				fatal("Missing query type");
			querytype = parse_type(argv[2]);
			if (querytype < 0)
				fatal("Invalid query type %s", argv[2]);
			argv++; argc--;
			break;

		    case 'a' :
			querytype = T_ANY;	/* filter anything available */
			break;

		    case 'm' :
			mailmode = TRUE;
			querytype = T_MAILB;	/* filter MINFO/MG/MR/MB data */
			break;
#ifdef justfun
		    case 'g' :
			if (argv[2] == NULL || argv[2][0] == '-')
				fatal("Missing minimum length");
			namelen = atoi(argv[2]);
			if (namelen <= 0)
				fatal("Invalid minimum length %s", argv[2]);
			argv++; argc--;
			break;
#endif
		    case 'X' :
			if (argv[2] == NULL || argv[2][0] == '-')
				fatal("Missing server name");
			servername = argv[2];
			argv++; argc--;
			/* fall through */

		    case 'x' :
			extended = TRUE;
			break;

		    case 'V' :
			printf("Version %s\n", version);
			exit(EX_OK);

		    default:
			fatal(Usage);
		}
	    }

	    argv++; argc--;
	}

/*
 * Check the remaining arguments.
 */
	/* old syntax must have at least one argument */
	if (!extended && (argc < 2 || argc > 3))
		fatal(Usage);

	/* old syntax has explicit server as second argument */
	if (!extended && (argc > 2))
		servername = argv[2];

/*
 * Open log file if requested.
 * Exchange role of stdout and logfile if so specified.
 */
	if (logfilename != NULL)
	{
		logfile = fopen(logfilename, "w");
		if (logfile == NULL)
		{
			perror(logfilename);
			exit(EX_CANTCREAT);
		}

		if (logexchange)
		{
#ifdef SWAPFILE_HACK
			swapfile(logfile, stdout);
#else
			fatal("Option -F not supported");
#endif
		}
	}

/*
 * Check for possible alternative server.
 */
	if (servername != NULL)
		set_server(servername);

	/* set new resolver values changed by command options */
	_res.retry = new_res.retry;
	_res.retrans = new_res.retrans;
	_res.options = new_res.options;

	/* show the new resolver database */
	if (debug > 1 || verbose > 1)
		show_res();

	/* show customized default domain */
	option = getenv("LOCALDOMAIN");
	if (option != NULL && verbose > 1)
		printf("Explicit local domain %s\n\n", option);

/*
 * Process command line argument(s) depending on syntax.
 */
	if (!extended) /* only one argument */
		result = process_name(argv[1]);

	else if (argc < 2) /* no arguments */
		result = process_file(stdin);

	else /* multiple command line arguments */
		result = process_argv(argc, argv);

	exit(result);
	/*NOTREACHED*/
}

/*
** SET_DEFAULTS -- Interpolate default options and parameters in argv
** ------------------------------------------------------------------
**
**	Returns:
**		None.
**
**	Outputs:
**		Creates new optargv vector with optargc arguments.
*/

void
set_defaults(option, argc, argv)
input char *option;			/* option string */
input int argc;
input char *argv[];
{
	register char *p, *q;
	register int i;

/*
 * Allocate new argument vector.
 */
	optargv = newlist(NULL, 2, char *);
	optargv[0] = argv[0];
	optargc = 1;

/*
 * Construct argument list from option string.
 */
	for (p = newstr(option); *p != '\0'; p = q)
	{
		while (is_space(*p))
			p++;

		if (*p == '\0')
			break;

		for (q = p; *q != '\0' && !is_space(*q); q++)
			continue;

		if (*q != '\0')
			*q++ = '\0';

		optargv = newlist(optargv, optargc+2, char *);
		optargv[optargc] = p;
		optargc++;
	}

/*
 * Append command line arguments.
 */
	for (i = 1; i < argc; i++)
	{
		optargv = newlist(optargv, optargc+2, char *);
		optargv[optargc] = argv[i];
		optargc++;
	}

	/* and terminate */
	optargv[optargc] = NULL;
}

/*
** PROCESS_ARGV -- Process command line arguments
** ----------------------------------------------
**
**	Returns:
**		EX_OK if information was obtained successfully.
**		Appropriate exit code otherwise.
*/

int
process_argv(argc, argv)
input int argc;
input char *argv[];
{
	register int i;
	int result;			/* result status of action taken */
	int excode = EX_NOINPUT;	/* overall result status */

	for (i = 1; i < argc; i++)
	{
		/* process a single argument */
		result = process_name(argv[i]);

		/* maintain overall result */
		if (result != EX_OK || excode == EX_NOINPUT)
			excode = result;
	}

	/* return overall result */
	return(excode);
}

/*
** PROCESS_FILE -- Process arguments from input file
** -------------------------------------------------
**
**	Returns:
**		EX_OK if information was obtained successfully.
**		Appropriate exit code otherwise.
*/

int
process_file(fp)
input FILE *fp;				/* input file with query names */
{
	register char *p, *q;
	char buf[BUFSIZ];
	int result;			/* result status of action taken */
	int excode = EX_NOINPUT;	/* overall result status */

	while (fgets(buf, sizeof(buf), fp) != NULL)
	{
		p = index(buf, '\n');
		if (p != NULL)
			*p = '\0';

		/* extract names separated by whitespace */
		for (p = buf; *p != '\0'; p = q)
		{
			while (is_space(*p))
				p++;

			/* ignore comment lines */
			if (*p == '\0' || *p == '#' || *p == ';')
				break;

			for (q = p; *q != '\0' && !is_space(*q); q++)
				continue;

			if (*q != '\0')
				*q++ = '\0';

			/* process a single argument */
			result = process_name(p);

			/* maintain overall result */
			if (result != EX_OK || excode == EX_NOINPUT)
				excode = result;
		}
	}