libes@nbs-amrf.UUCP (Don Libes) (05/16/86)
To summarize: There are times when it would be useful to have a
crt (for editing) on the console, and the rest of the time it would
be useful to have a printer (for information and error logging).
In case I wasn't clear before, let me restate: It is not true that
the online files keep accurate logs of what has printed on the
console. An excellent example is if a user halts the systems (or
the system bops out on its own like Sun's infamous "watchdog
reset"). A power outage and return could reboot the system, and
all the log would show was that the system was booted - no reason
and no record of it having been halted.
I got some real good responses. Both Jack Jansen <mcvax!jack> and
Rich Zellich <zellich@ALMSA-1.ARPA> suggested hooking up a
Decwriter to the printer port on the VT100. You may have to run
the VT100 at 1200 baud in order not to overflow the printer's
buffer, but it's a small price to pay. Just turn off the printer
while editing.
As for my suggestion of a PC console, John Sellens
<watdragon!jmsellens> tells me that the VAX 8500 uses a DEC PC as
the console (and DEC explicitly suggests adding a printer to the PC).
Ken Lalonde <watmath!kwlalonde> sent me what looks to be like a
real useful program. "/etc/fork" starts up a shell on a nearby CRT
while in single-user mode. Unfortunately, it looks like it
requires the source to getty (4.2BSD).
Thanks for all your responses. I hope this helps others.
Don Libes {seismo,umcp-cs}!nbs-amrf!libes
/etc/fork is reproduced below:
#!/bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #!/bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
# Makefile
# fork.8
# fork.c
# This archive created: Tue May 13 15:10:47 1986
# By: watmath!root (Ken Lalonde)
export PATH; PATH=/bin:$PATH
if test -f 'Makefile'
then
echo shar: over-writing existing file "'Makefile'"
fi
cat << \SHAR_EOF > 'Makefile'
CFLAGS=-O -I/usr/src/etc/getty
fork: fork.o gettytab.o subr.o init.o
cc fork.o gettytab.o subr.o init.o -o fork
gettytab.o: /usr/src/etc/getty/gettytab.c
cc -c $(CFLAGS) /usr/src/etc/getty/gettytab.c
subr.o: /usr/src/etc/getty/subr.c
cc -c $(CFLAGS) /usr/src/etc/getty/subr.c
init.o: /usr/src/etc/getty/init.c
cc -c $(CFLAGS) /usr/src/etc/getty/init.c
install: fork
install fork /etc
clean:
rm -f fork *.o
SHAR_EOF
if test -f 'fork.8'
then
echo shar: over-writing existing file "'fork.8'"
fi
cat << \SHAR_EOF > 'fork.8'
.TH FORK 8 LOCAL
.SH NAME
fork \- create a login shell while in single-user mode
.SH SYNOPSIS
.B /etc/fork
/dev/ttyxx
.SH DESCRIPTION
.B Fork
is used to create an instance of /bin/csh on the named terminal
while in single-user mode.
The named terminal must be hardwired.
.B Fork
is typically used when editing on a hardcopy console
becomes too frustrating.
.SH FILES
/etc/ttys for the terminal speed
SHAR_EOF
if test -f 'fork.c'
then
echo shar: over-writing existing file "'fork.c'"
fi
cat << \SHAR_EOF > 'fork.c'
/*
* fork tty
* Simulate some of the actions of getty and start csh
* on the named line. Makes sense only in single user
* mode, and only on hardwired lines.
*/
#include <sys/ioctl.h>
#include <stdio.h>
#include <ctype.h>
#include "gettytab.h"
char tabent[512];
char tabstrs[512];
char hostname[] = "jello pudding"; /* for the loader, never used */
struct sgttyb tmode = {
0, 0, CERASE, CKILL, 0
};
struct tchars tc = {
CINTR, CQUIT, CSTART,
CSTOP, CEOF, CBRK,
};
struct ltchars ltc = {
CSUSP, CDSUSP, CRPRNT,
CFLUSH, CWERASE, CLNEXT
};
int upper, lower, allflags;
main(argc, argv)
char **argv;
{
int fd;
char *c, *getletter();
if(argc != 2) {
fprintf(stderr, "Usage: fork ttyxx\n");
exit(1);
}
c = getletter(argv[1]);
if((fd = open("/dev/tty", 2)) < 0) {
perror("/dev/tty");
exit(1);
}
if(ioctl(fd, TIOCNOTTY, 0) < 0) {
perror("ioctl (TIOCNOTTY)");
exit(1);
}
for (fd = getdtablesize(); --fd >= 0; )
close(fd);
if((fd = open(argv[1], 2)) != 0) {
perror(argv[1]); /* useless */
exit(1);
}
dup(fd);
dup(fd);
gettable(c, tabent, tabstrs);
if (IS)
tmode.sg_ispeed = speed(IS);
else if (SP)
tmode.sg_ispeed = speed(SP);
if (OS)
tmode.sg_ospeed = speed(OS);
else if (SP)
tmode.sg_ospeed = speed(SP);
tmode.sg_flags = setflags(2) & 0xffff;
tmode.sg_flags &= ~LCASE;
tmode.sg_flags |= ECHO|CRMOD;
ioctl(0, TIOCSETP, &tmode);
if(fork() == 0) {
execl("/bin/csh", "-csh", 0);
perror("/bin/csh");
_exit(1);
}
exit(0);
}
char *
getletter(s)
char *s;
{
FILE *fd;
char line[256];
char *p;
static char x[2];
char *rindex();
if((fd = fopen("/etc/ttys", "r")) == NULL)
return "default";
if (p = rindex(s, '/'))
s = p+1;
while(fgets(line, sizeof(line), fd) != NULL) {
if (line[0] != '1')
continue;
p = line+1;
while(isalnum(*++p))
;
*p = 0;
if(strcmp(s, line+2) == 0) {
x[0] = line[1];
x[1] = 0;
fclose(fd);
return x;
}
}
fclose(fd);
return "default";
}
SHAR_EOF
# End of shell archive
exit 0