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Date: Wed, 27 Sep 1995 21:01:39 +0100
From: hohmuth@inf.tu-dresden.de
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Subject: bin/746: `talk' forbids talking from write-protected terminal for no good reason
Sender: owner-bugs@freebsd.org
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>Number:         746
>Category:       bin
>Synopsis:       `talk' forbids talking from write-protected terminal for no good reason
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Sep 27 13:10:03 PDT 1995
>Last-Modified:
>Originator:     Michael Hohmuth
>Organization:
Dept. of Computer Science, TU Dresden, Germany
>Release:        FreeBSD 2.0.5-RELEASE i386
>Environment:

"uname -a" yields:

FreeBSD olymp.inf.tu-dresden.de 2.0.5-RELEASE FreeBSD 2.0.5-RELEASE #0: Wed Jul  5 12:39:10  1995     root@olymp.inf.tu-dresden.de:/usr/src/sys/compile/OLYMP  i386

>Description:

The `talk' program has a misfeature in that it cannot be used except
from a terminal with messages on ("mesg y").  When used from a
write-protected terminal (messages off, "mesg n"), it complains that
``The callee cannot write to this terminal, use "mesg y"''.  While
this is indisputable, there is no good reason to forbid usage of the
`talk' program in this case: It is very well possible to establish a
`talk' session from a write-protected terminal; this can easily be
demonstrated after removing this misfeature.

(One might even argue _for_ write-protecting one's terminal before
initiating a `talk' session that this prevents other talk requests
from arriving in this very terminal.)

>How-To-Repeat:

olymp:~> mesg n
Exit 1
olymp:~> talk hohmuth@irs
talk: The callee cannot write to this terminal, use "mesg y".
Exit 1

>Fix:

diff -u /usr/src/usr.bin/talk/init_disp.c ./init_disp.c
--- /usr/src/usr.bin/talk/init_disp.c	Tue May 30 08:34:33 1995
+++ ./init_disp.c	Wed Sep 27 20:38:23 1995
@@ -51,22 +51,6 @@
 #include "talk.h"
 
 /*
- * Make sure the callee can write to the screen
- */
-void check_writeable()
-{
-	char *tty;
-	struct stat sb;
-
-	if ((tty = ttyname(STDERR_FILENO)) == NULL)
-		err(1, "ttyname");
-	if (stat(tty, &sb) < 0)
-		err(1, "%s", tty);
-	if (!(sb.st_mode & S_IWGRP))
-		errx(1, "The callee cannot write to this terminal, use \"mesg y\".");
-}
-
-/*
  * Set up curses, catch the appropriate signals,
  * and build the various windows.
  */
diff -u /usr/src/usr.bin/talk/talk.c ./talk.c
--- /usr/src/usr.bin/talk/talk.c	Tue May 30 08:34:41 1995
+++ ./talk.c	Wed Sep 27 20:38:56 1995
@@ -63,7 +63,6 @@
 	char *argv[];
 {
 	get_names(argc, argv);
-	check_writeable();
 	init_display();
 	open_ctl();
 	open_sockt();
>Audit-Trail:
>Unformatted: