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Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!seismo!mcvax!denise
From: denise@mcvax.UUCP
Newsgroups: comp.bugs.4bsd
Subject: Curses Bug
Message-ID: <233@sering.mcvax.cwi.nl>
Date: Thu, 26-Mar-87 07:36:24 EST
Article-I.D.: sering.233
Posted: Thu Mar 26 07:36:24 1987
Date-Received: Sat, 28-Mar-87 05:47:34 EST
Reply-To: denise@sering.UUCP (Denise L. Draper)
Distribution: world
Organization: CWI, Amsterdam
Lines: 72

Index:	/usr/src/usr.lib/libcurses/cr_tty.c

Description:
	Curses writes to a pointer that points to the static environment
	variable TERM.  This can cause problems if an exec is then done.

Repeat-By:
	%cat > foo.c
	#include <curses.h>
	extern char **environ;
	
	main()
	{
		char *x;
		initscr();
		endwin();
			/* show the values of the environment variables */
			/* Note that TERM is now screwed up		*/
		while((x = *environ++) != NULL)
			printf("%s\n",x);

		execl("/bin/sh", "sh", "-c", "date", 0);
	}
	^D
	
	%cc foo.c -lcurses -ltermcap
	%setenv TERM h2		# or any other of the two-letter names
	%a.out

	The crucial feature is that the variable TERM must be shorter than
	the 2nd terminal name in the appropriate TERMCAP entry (another
	bug, I think: the function longname in curses claims to find the
	long name of the terminal, while in fact it simply finds the 2nd
	name).

Fix:
	Apply the following diff:

	*** cr_tty.c.old	Thu Mar 26 11:34:22 1987
	--- cr_tty.c		Thu Mar 26 11:34:54 1987
	***************
	*** 6,11 ****
	--- 6,12 ----
	  
	  #ifndef lint
	  static char sccsid[] = "@(#)cr_tty.c	5.2 (Berkeley) 11/8/85";
	+ static char sccsid2[] = "@(#)cr_tty.c	1.2 (CWI Mods) 87/03/26";
	  #endif not lint
	  
	  /*
	***************
	*** 134,141 ****
	  
	  	PC = _PC ? _PC[0] : FALSE;
	  	aoftspace = _tspace;
	! 	strncpy(ttytype, longname(genbuf, type), sizeof(ttytype) - 1);
	! 	ttytype[sizeof(ttytype) - 1] = '\0';
	  	if (unknown)
	  		return ERR;
	  	return OK;
	--- 135,141 ----
	  
	  	PC = _PC ? _PC[0] : FALSE;
	  	aoftspace = _tspace;
	! 	longname(genbuf,ttytype);
	  	if (unknown)
	  		return ERR;
	  	return OK;


denise
denise@cwi.nl