listen.c

操作系统SunOS 4.1.3版本的源码

			sprintf(scratch, nlsunknown, svc_code_p);
			logmessage(scratch);
			nls_reply(NLSUNKNOWN, scratch);
		}

	}  else
		error(E_BAD_FORMAT, CONTINUE);

	/* if we're still here, server didn't get exec'ed	*/

	return(-1);
}



/*
 * nls_chkmsg:	validate message and return fields to caller.
 *		returns: TRUE == good format
 *			 FALSE== bad format
 */

nls_chkmsg(bp, size, lowp, highp, svc_code_p)
char *bp, *svc_code_p;
int size, *lowp, *highp;
{

	/* first, make sure bp is null terminated */

	if ((*(bp + size - 1)) != (char)0)
		return(0);

	/* scanf returns number of "matched and assigned items"	*/

	return(sscanf(bp, "%*4c:%3d:%3d:%s", lowp, highp, svc_code_p) == 3);

}


/*
 * nls_reply:	send the "service request response message"
 *		when appropriate.  (Valid if running version 2 or greater).
 *		Must use write(2) since unknown modules may be pushed.
 *
 *		Message format:
 *		protocol_verion_# : message_code_# : message_text
 */

static char *srrpprot = "%d:%d:%s";

nls_reply(code, text)
register code;
register char *text;
{
	char scratch[256];

	/* Nlsversion = -1 for login service */

	if (Nlsversion >= 2)  {
		DEBUG((7, "nls_reply: sending response message"));
		sprintf(scratch, srrpprot, Nlsversion, code, text);
		t_snd(0, scratch, strlen(scratch)+1, 0);
	}
}


/*
 * common code to  start a server process (for any service)
 * if optional argv is given, info comes from o_argv, else pointer
 * to dbf struct is used.  In either case, first argument in argv is
 * full pathname of server. Before exec-ing the server, the caller's
 * logical address, opt and udata are addded to the environment. 
 */

start_server(netfd, dbp, o_argv, call)
int netfd;
register dbf_t *dbp;
register char **o_argv;
struct t_call *call;
{
	char *path;
	char **argvp;
	extern char **environ;
	extern struct passwd *getpwnam();
	extern void endpwent();
	extern struct group *getgrgid();
	register struct passwd *pwdp;
	struct group *grpp;
	char msgbuf[256];
	register dbf_t *wdbp = dbp;

	/*
	 * o_argv is set during SMB service setup only, in
	 * which case dbp is NULL.
	 */

	if (o_argv) {
		argvp = o_argv;
		if ((wdbp = getdbfentry(DBF_SMB_CODE)) == NULL) {
			/* this shouldn't happen because at this point we've
			   already found it once */
			logmessage("SMB message, missing data base entry");
			exit(2); /* server, don't log */
		}
	}
	else
		argvp = mkdbfargv(dbp);
	path = *argvp;

	/* set up stdout and stderr before pushing optional modules */

	(void) close(1);
	(void) close(2);

	if (dup(0) != 1 || dup(0) != 2) {
		logmessage("Dup of fd 0 failed");
		exit(2); /* server, don't log */
	}

	sprintf(msgbuf,"Starting server (%s)",path);
	nls_reply(NLSSTART, msgbuf);
	logmessage(msgbuf);

	/* after pushmod, tli calls are questionable?		*/

	if (dbp && pushmod(netfd, dbp->dbf_modules)) {
		logmessage("Can't push server's modules: exit");
		exit(2); /* server, don't log */
	}

	rst_signals();

	if (wdbp == NULL) {
		logmessage("No database entry");
		exit(2); /* server, don't log */
	}

/*
	if ((pwdp = getpwnam(wdbp->dbf_id)) == NULL) {
		sprintf(msgbuf, "Missing or bad passwd entry for <%s>", wdbp->dbf_id);
		logmessage(msgbuf);
		exit(2); */ /* server, don't log */
/*
	}

	if (setgid(pwdp->pw_gid)) {
		if ((grpp = getgrgid(pwdp->pw_gid)) == NULL) {
			sprintf(msgbuf, "No group entry for %d", pwdp->pw_gid);
			logmessage(msgbuf);
			exit(2); */ /* server, don't log */
/*
		}
		sprintf(msgbuf, "Cannot set group id to %s", grpp->gr_name);
		logmessage(msgbuf);
		exit(2); */ /* server, don't log */
/*
	}

	if (setuid(pwdp->pw_uid)) {
		sprintf(msgbuf, "Cannot set user id to %s", wdbp->dbf_id);
		logmessage(msgbuf);
		exit(2); */ /* server, don't log */
/*
	}

	if (chdir(pwdp->pw_dir)) {
		sprintf(msgbuf, "Cannot chdir to %s", pwdp->pw_dir);
		logmessage(msgbuf);
		exit(2); */ /* server, don't log */
/*
	}

	DEBUG((9, "New uid %d New gid %d", getuid(), getgid()));
	if (senviron(call, pwdp->pw_dir))  {
		logmessage("Can't expand server's environment");
	}
	endpwent();
*/

	execve(path, argvp, environ);

	/* exec returns only on failure!		*/

	logmessage("listener could not exec server");
	sys_error(E_SYS_ERROR, CONTINUE);
	return(-1);
}


/*
 * senviron:	Update environment before exec-ing the server:
 *		The callers logical address is placed in the
 *		environment in hex/ascii character representation.
 *
 * Note:	no need to free the malloc'ed buffers since this process
 *		will either exec or exit.
 */

static char provenv[2*PATHSIZE];
static char homeenv[BUFSIZ];
static char tzenv[BUFSIZ];

#define TIMEZONE	"/etc/TIMEZONE"
#define TZSTR	"TZ="

int
senviron(call, home)
register struct t_call *call;
register char *home;
{
	register char *p;
	char scratch[BUFSIZ];
	extern void nlsaddr2c();
	extern char *getenv();
	char *parse();
	FILE *fp;

	sprintf(homeenv, "HOME=%s", home);
	putenv(homeenv);

/*
 * The following code handles the case where the listener was started with
 * no environment.  If so, supply a reasonable default path and find out
 * what timezone we're in so the log file is consistent.
 */

	if (getenv("PATH") == NULL)
		putenv("PATH=/bin:/etc:/usr/bin");
	if (getenv("TZ") == NULL) {
		fp = fopen(TIMEZONE, "r");
		if (fp) {
			while (fgets(tzenv, BUFSIZ, fp)) {
				if (scratch[strlen(tzenv) - 1] == '\n')
					tzenv[strlen(tzenv) - 1] = '\0';
				if (!strncmp(TZSTR, tzenv, strlen(TZSTR))) {
					putenv(parse(tzenv));
					break;
				}
			}
			fclose(fp);
		}
		else {
			sprintf(scratch, "couldn't open %s, default to GMT", TIMEZONE);
			logmessage(scratch);
		}
	}

	if ((p = (char *)malloc(((call->addr.len)<<1) + 18)) == NULL)
		return(-1);
	strcpy(p, NLSADDR);
	strcat(p, "=");
	nlsaddr2c(p + strlen(p), call->addr.buf, call->addr.len);
	DEBUG((7, "Adding %s to server's environment", p));
	putenv(p);

	if ((p = (char *)malloc(((call->opt.len)<<1) + 16)) == NULL)
		return(-1);
	strcpy(p, NLSOPT);
	strcat(p, "=");
	nlsaddr2c(p + strlen(p), call->opt.buf, call->opt.len);
	DEBUG((7, "Adding %s to server's environment", p));
	putenv(p);

	p = provenv;
	strcpy(p, NLSPROVIDER);
	strcat(p, "=");
	strcat(p, Netspec);
	DEBUG((7, "Adding %s to environment", p));
	putenv(p);

	if ((p = (char *)malloc(((call->udata.len)<<1) + 20)) == NULL)
		return(-1);
	strcpy(p, NLSUDATA);
	strcat(p, "=");
	if ((int)call->udata.len >= 0)
		nlsaddr2c(p + strlen(p), call->udata.buf, call->udata.len);
	DEBUG((7, "Adding %s to server's environment", p));
	putenv(p);
	return (0);
}


/*
 * parse:	Parse TZ= string like init does for consistency
 *		Work on string in place since result will
 *		either be the same or shorter.
 */

char *
parse(s)
char *s;
{
	register char *p;
	register char *tp;
	char scratch[BUFSIZ];
	int delim;

	tp = p = s + strlen("TZ=");	/* skip TZ= in parsing */
	if ((*p == '"') || (*p == '\'')) {
		/* it is quoted */
		delim = *p++;
		for (;;) {
			if (*p == '\0') {
				/* etc/TIMEZONE ill-formed, go without TZ */
				sprintf(scratch, "%s ill-formed", TIMEZONE);
				logmessage(scratch);
				strcpy(s, "TZ=");
				return(s);
			}
			if (*p == delim) {
				*tp = '\0';
				return(s);
			}
			else {
				*tp++ = *p++;
			}
		}
	}
	else { /* look for comment or trailing whitespace */
		for ( ; *p && !isspace(*p) && *p != '#'; ++p)
			;
		/* if a comment or trailing whitespace, trash it */
		if (*p) {
			*p = '\0';
		}
		return(s);
	}
}


/*
 * login:	Start the intermediary process that handles
 *		pseudo-tty getty/login service.
 */

login(fd, call)
register fd;
struct t_call *call;
{
	register dbf_t *dbp;

	DEBUG((9,"in login (request for intermediary)"));

	if (!(dbp = getdbfentry(DBF_INT_CODE)) || (dbp->dbf_flags & DBF_OFF))  {
		log( E_NOINTERMEDIARY );
		return(-1);
	}

	start_server(fd, dbp, (char **)0, call);

	/* returns only on failure!			*/

	logmessage("listener could not exec the intermediary process");
	sys_error(E_SYS_ERROR, CONTINUE);

	return(-1);
}


/*
 * isdigits:	string version of isdigit.  (See ctype(3))
 */

int
isdigits(p)
register char *p;
{
	register int flag = 1;

	if (!strlen(p))
		return(0);

	while (*p)
		if (!isdigit(*p++))
			flag = 0;
	return(flag);
}


/*
 * pushmod:	push modules if defined in the data base entry.
 *
 *		NOTE: there are no modules to push in WTLI.
 *		so this code is a noop on the S4.  However,
 *		the data base file is compatible.
 *
 *		WARNING: This routine writes into the in-memory copy
 *		of the database file.  Therefore, after it is called,
 *		the incore copy of the database file will no longer be valid.
 */

int
pushmod(fd, mp)
int fd;
register char *mp;
{
#ifndef	S4
	register char *cp = mp;
	register int pflag = 0;
	char name[32];

	DEBUG((9,"in pushmod:"));
	if (!mp) {
		DEBUG((9,"NULL list: exiting pushmod"));
		return(0);
	}
	while (*cp) {
	    if (*cp == ',') {
	    	*cp = (char)0;
		if (*mp && strcmp(mp, "NULL")) {

	/*
	 * if first time thru, pop off TIMOD if it is on top of stream
	 */

		    if  (!pflag) {
			pflag++;
			if (ioctl(fd, I_LOOK, name) >= 0) {
			    if (strcmp(name, "timod") == 0) {
				if (ioctl(fd, I_POP) < 0)
				    DEBUG((9,"pushmod: I_POP failed"));
			    }
			}
		    }

		    DEBUG((9,"pushmod: about to push %s",mp));
		    if (ioctl(fd, I_PUSH, mp) < 0) {
			DEBUG((9,"pushmod: ioctl failed, errno = %d",errno));
			return(1);
		    }

		} /* if */
		mp = ++cp;
		continue;
	    } /* if */
	    cp++;
	} /* while */
	DEBUG((9,"exiting pushmod:"));
#endif
	return(0);
}


int
l_rcv(fd, bufp, bytes, flagp)
int fd;
char *bufp;
int bytes;
int *flagp;
{
	register int n;
	register int count = bytes;
	register char *bp = bufp;

	DEBUG((9, "in l_rcv"));

	do {
		*flagp = 0;
		n = t_rcv(fd, bp, count, flagp);
		if (n < 0) {
			DEBUG((9, "l_rcv, t_errno is %d", t_errno));
#ifdef DEBUGMODE
			if (t_errno == TLOOK) {
				DEBUG((9, "l_rcv, t_look returns %d", t_look(fd)));
			}
#endif
			return(n);
		}
		count -= n;
		bp += n;
	} while (count > 0);

	return(bp - bufp);
}


/*
 * clr_call:	clear out a call structure
 */

clr_call(call)
struct t_call *call;
{
	call->sequence = 0;
	call->addr.len = 0;
	call->opt.len = 0;
	call->udata.len = 0;
	memset(call->addr.buf, 0, call->addr.maxlen);
	memset(call->opt.buf, 0, call->opt.maxlen);
	memset(call->udata.buf, 0, call->udata.maxlen);
}


/*
 * pitchcall: remove call from pending list
 */

pitchcall(free, pending, disc)
struct call_list *free;
struct call_list *pending;
struct t_discon *disc;
{
	register struct callsave *p, *oldp;

	DEBUG((9, "pitching call, sequence # is %d", disc->sequence));
	if (EMPTY(pending)) {
		disc->sequence = -1;
		return;
	}
	p = pending->cl_head;
	oldp = (struct callsave *) NULL;
	while (p) {
		if (p->c_cp->sequence == disc->sequence) {
			if (oldp == (struct callsave *) NULL) {
				pending->cl_head = p->c_np;
				if (pending->cl_head == (struct callsave *) NULL) {
					pending->cl_tail = (struct callsave *) NULL;
				}
			}
			else if (p == pending->cl_tail) {
				oldp->c_np = p->c_np;
				pending->cl_tail = oldp;
			}
			else {
				oldp->c_np = p->c_np;
			}
			clr_call(p->c_cp);
			queue(free, p);
			disc->sequence = -1;
			return;
		}
		oldp = p;
		p = p->c_np;
	}
	logmessage("received disconnect with no pending call");
	disc->sequence = -1;
	return;
}