smb@ulysses.UUCP (11/22/83)
Has anyone implemented any sort of "autobaud" capability on any version of UNIX? That is, I'd like to get away from clumsy mechanisms like cycling through the speed table. Many (most?) port selectors and the like can recognize your speed from a simple CR or some such; has anyone modified UNIX to do the same? My guess is that on 4.1/4.2bsd, it would take changes to getty.c and the tty driver; on 5.0, it might just be possible to do it all in getty.c.
chris@umcp-cs.UUCP (11/22/83)
We do it all the time.
I believe I posted our version of getty.c to net.sources. It reads
yet another /etc/tty table ("/etc/tty.init" -- maybe I should have
called it "/etc/tty.getty"?) instead of having the table hard-coded,
and has an auto-baud routine written by Fred Blonder. The basic
idea is to look at a carriage return at 2400 baud, and, based on
the resultant bit pattern, guess the real tty speed. Works pretty
well.
I suppose I can re-post it if enought people are interested.
Chris
--
In-Real-Life: Chris Torek, Univ of MD Comp Sci
UUCP: {seismo,allegra,brl-bmd}!umcp-cs!chris
CSNet: chris@umcp-cs ARPA: chris.umcp-cs@CSNet-Relaythomas@utah-gr.UUCP (Spencer W. Thomas) (11/22/83)
4.2Bsd getty uses a "ttycap" file, but I don't think it does autobauding. =Spencer
jim@mcvax.UUCP (Jim McKie) (11/23/83)
We don't have any terminals/modems/diallers/etc. on our machines,
everything is attached to a Micom portselector. So we have autobaud
detection in getty. Originally done by mcvax!piet, added to 4.2BSD
by me. Here is a diff of the source with the original, followed by
a copy of /etc/gettytab. It isn't hard to fit it into a non-4.2BSD.
Jim McKie Mathematisch Centrum, Amsterdam ....mcvax!jim
======================================================================
diff -c ./gettytab.h /usr/src/local/etc/getty/gettytab.h
*** ./gettytab.h Sun Jul 10 03:35:15 1983
--- /usr/src/local/etc/getty/gettytab.h Sun Sep 18 13:13:13 1983
***************
*** 97,102
#define PS gettyflags[16].value
#define HC gettyflags[17].value
#define UB gettyflags[18].value
int getent();
long getnum();
--- 97,105 -----
#define PS gettyflags[16].value
#define HC gettyflags[17].value
#define UB gettyflags[18].value
+ #ifdef MCVAX
+ #define AB gettyflags[19].value
+ #endif MCVAX
int getent();
long getnum();
diff -c ./init.c /usr/src/local/etc/getty/init.c
*** ./init.c Sun Jul 10 03:35:16 1983
--- /usr/src/local/etc/getty/init.c Sun Sep 18 13:13:13 1983
***************
*** 80,84
{ "ps", 0 }, /* do port selector speed select */
{ "hc", 1 }, /* don't set hangup on close */
{ "ub", 0 }, /* unbuffered output */
{ 0 }
};
--- 80,87 -----
{ "ps", 0 }, /* do port selector speed select */
{ "hc", 1 }, /* don't set hangup on close */
{ "ub", 0 }, /* unbuffered output */
+ #ifdef MCVAX
+ { "ab", 0 }, /* auto-baud detect with '\r' */
+ #endif MCVAX
{ 0 }
};
diff -c ./main.c /usr/src/local/etc/getty/main.c
*** ./main.c Tue Aug 2 01:07:07 1983
--- /usr/src/local/etc/getty/main.c Sun Sep 18 13:13:13 1983
***************
*** 128,133
ioctl(0, TIOCSETD, &ldisp);
if (HC)
ioctl(0, TIOCHPCL, 0);
if (PS) {
tname = portselector();
continue;
--- 128,141 -----
ioctl(0, TIOCSETD, &ldisp);
if (HC)
ioctl(0, TIOCHPCL, 0);
+ #ifdef MCVAX
+ if (AB) {
+ extern char *autobaud();
+
+ tname = autobaud();
+ continue;
+ }
+ #endif MCVAX
if (PS) {
tname = portselector();
continue;
diff -c ./subr.c /usr/src/local/etc/getty/subr.c
*** ./subr.c Thu Jul 7 12:32:55 1983
--- /usr/src/local/etc/getty/subr.c Tue Oct 11 10:09:55 1983
***************
*** 406,408
sleep(2); /* wait for connection to complete */
return (type);
}
--- 406,463 -----
sleep(2); /* wait for connection to complete */
return (type);
}
+
+ #ifdef MCVAX
+ /*
+ * This auto-baud speed select machanism is written for the Micom 600
+ * portselector. Selection is done by looking at how the character '\r'
+ * is garbled at the different speeds.
+ */
+ #include <sys/time.h>
+
+ char *
+ autobaud()
+ {
+ int rfds;
+ struct timeval timeout;
+ char c, *type = "2400-baud";
+ int null = 0;
+
+ ioctl(0, TIOCFLUSH, &null);
+ rfds = 1 << 0;
+ timeout.tv_sec = 5;
+ timeout.tv_usec = 0;
+ if(select(32, &rfds, (int *)0, (int *)0, &timeout) <= 0)
+ return(type);
+ if(read(0, &c, sizeof(char)) != sizeof(char))
+ return(type);
+ timeout.tv_sec = 0;
+ timeout.tv_usec = 20;
+ (void) select(32, (int *)0, (int *)0, (int *)0, &timeout);
+ ioctl(0, TIOCFLUSH, &null);
+ switch(c&0377){
+
+ case 0200: /* 300-baud */
+ type = "300-baud";
+ break;
+
+ case 0346: /* 1200-baud */
+ type = "1200-baud";
+ break;
+
+ case 015: /* 2400-baud */
+ case 0215:
+ type = "2400-baud";
+ break;
+
+ default: /* 4800-baud */
+ type = "4800-baud";
+ break;
+
+ case 0377: /* 9600-baud */
+ type = "9600-baud";
+ break;
+ }
+ return(type);
+ }
+ #endif MCVAX
===========================================================================
/etc/gettytab
===========================================================================
#
# Mathematisch Centrum gettytab.
#
#
# The default gettytab entry, used to set defaults for all other
# entries, and in cases where getty is called with no table name
#
default:\
:ap:er=^H:kl=^X:in=\177:sp#2400:cd#3:im=\r\n%h\r\n\007:
#
# Auto-baud speed detect entry for Micom 600.
# Special code in getty will switch this out
# to one of the other entries.
#
A|Auto-baud:\
:ab:sp#2400:f0#040:
#
# Other general speed tables. These can be cycled-round
# by using "break" (watch on the Micom!).
# The names "SPEED-baud" are also known to the special
# code in getty for auto-baud.
#
B|300-baud:\
:nx=9600-baud:cd@:sp#300:
C|1200-baud:\
:nx=300-baud:cd@:sp#1200:
D|2400-baud:\
:nx=1200-baud:
E|4800-baud:\
:nx=2400-baud:cd@:sp#4800:
F|9600-baud:\
:nx=4800-baud:cd@:sp#9600:
#
# Fixed-speed dialup lines.
#
H|Dialup-1200:\
:cd@:sp#1200:
L|Dialup-300:\
:cd@:sp#300:
#
# Console Decwriter-III
#
c|Console|Console Decwriter III:\
:cd@:fd#1:ht: