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Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!seismo!mimsy!chris
From: chris@mimsy.UUCP
Newsgroups: comp.unix.questions
Subject: Re: login gripes
Message-ID: <6008@mimsy.UUCP>
Date: Sun, 29-Mar-87 20:31:22 EST
Article-I.D.: mimsy.6008
Posted: Sun Mar 29 20:31:22 1987
Date-Received: Tue, 31-Mar-87 01:07:11 EST
References: <8703231450.AA18626@ephemeral.ai.toronto.edu>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 170

In article <8703231450.AA18626@ephemeral.ai.toronto.edu>
lamy@ai.toronto.edu writes:
>a) What on earth does [login] do between the time I hit return on
>   the username line and the time it gives me back the Password prompt?

That is not login, but rather getty, that you are running.  It is exec'ing
login.

>b) Any fundamental reason why true baud rate detection is not provided?

It *is* provided---you just have to know who to ask. :-)

RCS file: RCS/subr.c,v
retrieving revision 1.1
diff -c2 -r1.1 subr.c
*** /tmp/,RCSt1003237	Sun Mar 29 20:30:25 1987
--- subr.c	Sat Oct  5 06:40:21 1985
***************
*** 417,420 ****
--- 417,422 ----
  }
  
+ #ifdef notdef
+ 
  /*
   * This auto-baud speed select mechanism is written for the Micom 600
***************
*** 469,470 ****
--- 471,608 ----
  	return (type);
  }
+ 
+ #else
+ 
+ /*
+  * Try to figure out what speed the terminal is set to based on what
+  * a carriage-return or newline looks like at 2400 baud.  5/18/82 FLB
+  *
+  * N.B.: some of the table entries for \n collide with those for \r.
+  * Only the first one in the table will be matched.
+  */
+ 
+ #include <sys/types.h>
+ #include <sys/time.h>
+ #include <signal.h>
+ #include <setjmp.h>
+ 
+ struct autobaud {
+ 	char *s_speed;
+ 	char *s_string;		/* first byte is length */
+ } a_tab[] = {
+ 	/* carriage-return */
+ 	"110-baud",	"\3\000\000\000",	/* also \n */
+ 	"300-baud",	"\3\200\200\000",	/* collides with 600 \n */
+ 	"300-baud",	"\3\200\000\000",
+ 	"300-baud",	"\3\000\200\000",	/* also \n */
+ 	"600-baud",	"\3\000\376\000",
+ 	"1200-baud",	"\2\346\200",
+ 	"1200-baud",	"\2\346\340",
+ 	"1200-baud",	"\2\367\300",
+ 	"1800-baud",	"\2\000\376",		/* also \n */
+ 	"1800-baud",	"\2\000\377",
+ 	"2400-baud",	"\1\015",
+ 	"2400-baud",	"\1\215",
+ 	"4800-baud",	"\1\361",		/* needed for Gandalf */
+ 	"4800-baud",	"\1\362",
+ 	"4800-baud",	"\1\363",		/* needed for Gandalf */
+ 	"4800-baud",	"\1\371",		/* needed for Gandalf */
+ 	"4800-baud",	"\1\375",		/* needed for Gandalf */
+ 	"4800-baud",	"\1\376",		/* needed for Gandalf;
+ 						   collides with 9600 \n */
+ 	"9600-baud",	"\1\377",		/* needed for Gandalf */
+ 
+ 	/* newline */
+ 	"600-baud",	"\3\200\000\000",	/* collides with 300 \r */
+ 	"1200-baud",	"\2\230\200",
+ 	"2400-baud",	"\1\012",
+ 	"4800-baud",	"\1\370",
+ 	"9600-baud",	"\1\376",		/* collides with 4800 \r */
+ 
+ 	/* The next entry must be the last entry in the table. */
+ 	0,		"\1\0",			/* BREAK: handled specially */
+ 
+ 	0,		0
+ };
+ 
+ char *
+ autobaud()
+ {
+ 	register struct autobaud *tp;
+ 	register int i;
+ 	struct sgttyb ttyb;
+ 	static char buf[10];
+ 
+ 	extern jmp_buf timeout;	/* from main.c */
+ 	extern int dingdong();	/* from main.c */
+ 
+ 	if (TO) {
+ 		if (setjmp(timeout)) {
+ 			/*
+ 			 * Drop DTR for a while.  This is important
+ 			 * for Gandalf lines which must be told to
+ 			 * disconnect.
+ 			 */
+ 			ttyb.sg_ispeed = ttyb.sg_ospeed = 0;
+ 			(void) ioctl(0, TIOCSETP, &ttyb);
+ 			sleep(3);
+ 			exit(1);
+ 		}
+ 		signal(SIGALRM, dingdong);
+ 		alarm(TO);
+ 	}
+ 
+ 	/*
+ 	 * The following hack sets BREAK to sequence to the next
+ 	 * gettytab entry.
+ 	 */
+ 	a_tab[(sizeof (a_tab) / sizeof (a_tab[0])) - 2].s_speed =
+ 	    NX && *NX ? NX : 0;
+ 
+ 	ttyb.sg_ispeed = ttyb.sg_ospeed = B2400;
+ 	ttyb.sg_flags = ANYP|RAW;
+ 
+ 	for (;;) {
+ 		(void) ioctl(0, TIOCSETP, &ttyb);
+ 		input(buf, sizeof buf);
+ 
+ 		for (tp = a_tab; tp->s_speed; tp++) {
+ 			for (i = 0;; i++) {
+ 				if (buf[i] != tp->s_string[i])
+ 					break;
+ 				if (i == buf[0]) {
+ 					alarm(0);
+ 					return (tp->s_speed);
+ 				}
+ 			}
+ 		}
+ 	}
+ 	/*NOTREACHED*/
+ }
+ 
+ input(s, n)
+ 	char *s;
+ 	register int n;
+ {
+ 	register char *cp = s + 1;
+ 	fd_set rfds;
+ 	struct timeval timeout;
+ 
+ 	FD_ZERO(&rfds);
+ 	FD_SET(0, &rfds);
+ 	timeout.tv_sec = 0;	/* .15 seconds */
+ 	timeout.tv_usec = 150000;
+ 	n--;			/* first byte is for length */
+ 	(void) read(0, cp, 1);	/* wait for something */
+ 	n--, cp++;
+ 	while (--n >= 0) {
+ 		if (select(1, &rfds, (fd_set *)0, (fd_set *)0, &timeout) <= 0)
+ 			break;
+ 		if (read(0, cp, 1) != 1)
+ 			break;
+ 		cp++;
+ 	}
+ 	*s = (cp - s) - 1;
+ }
+ 
+ #endif
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
UUCP:	seismo!mimsy!chris	ARPA/CSNet:	chris@mimsy.umd.edu