[net.unix-wizards] A few small bugs in 4.2bsd learn...

dan@rna.UUCP (02/19/84)

Subject: Few bugs with learn
Index:	/usr/src/usr.bin/learn/copy.c 4.2BSD

Description:
	1) Typing EOT to learn causes learn to loop on error from stdin.
	2) learn scripts files, eqn, vi cannot startup at all.
Repeat-By:
	(above)
Fix:
	1) In the file, copy.c, add clearerr(stdin)...

*** copy.c.org	Tue Apr 26 03:04:22 1983
--- copy.c	Sat Feb 18 18:11:11 1984
***************
*** 34,35
  			if (fin == stdin) {
  				fprintf(stderr, "Type \"bye\" if you want to leave learn.\n");

--- 34,36 -----
  			if (fin == stdin) {
+ 				clearerr(stdin);
  				fprintf(stderr, "Type \"bye\" if you want to leave learn.\n");


	2) chmod 755 /usr/lib/learn/files/Init /usr/lib/learn/eqn/Init \
			/usr/lib/learn/vi/Init

					Cheers,
					Dan Ts'o
					...cmcl2!rna!dan

smk@axiom.UUCP (Steven M. Kramer) (02/19/84)

And there is another bug ...
The tty is not reset after the session in learn is over.
For the files lesson, the /usr/src/usr.lib/learn/files/Init file
contains a stty which is not undone by learn itself upon wrapup.
The fix is to simply save the terminal state before executing Init
and then restore it upon wrapup.
	--steve kramer

diff -c follows on learn.c and wrapup.c:
-----------
*** learn.c.orig	Thu Jan 19 11:39:28 1984
--- learn.c	Thu Jan 19 11:40:59 1984
***************
*** 5,10
  #include "stdio.h"
  #include "lrnref.h"
  #include "signal.h"
  
  char	*direct	= "/usr/lib/learn";	/* CHANGE THIS ON YOUR SYSTEM */
  int	more;

--- 5,16 -----
  #include "stdio.h"
  #include "lrnref.h"
  #include "signal.h"
+ #ifdef AXIOM
+ /* For saving the terminal state before entering learn and then
+    restoring if upon exiting.
+ */
+ #include "sgtty.h"
+ #endif
  
  char	*direct	= "/usr/lib/learn";	/* CHANGE THIS ON YOUR SYSTEM */
  int	more;
***************
*** 27,32
  int	skip;
  int	teed;
  int	total;
  
  main(argc,argv)
  int argc;

--- 33,48 -----
  int	skip;
  int	teed;
  int	total;
+ #ifdef AXIOM
+ /*
+  * Fixes a bug whereby the learn program leaves you in a stty state
+  * fixed by whaever program you were running.  We use this sgttyb
+  * to save the state upon entering learn.  The corresponsing reset
+  * code is in wrapup() in wrapup.c
+  * Steve Kramer 1/20/84
+  */
+ struct sgttyb save_terminal_state;
+ #endif
  
  main(argc,argv)
  int argc;
***************
*** 36,41
  	extern char * getlogin();
  	char *malloc();
  
  	speed = 0;
  	more = 1;
  	pwline = getlogin();

--- 52,60 -----
  	extern char * getlogin();
  	char *malloc();
  
+ #ifdef AXIOM
+ 	gtty (fileno (stdin), &save_terminal_state);
+ #endif
  	speed = 0;
  	more = 1;
  	pwline = getlogin();
*** wrapup.c.orig	Tue Apr 26 03:04:34 1983
--- wrapup.c	Thu Jan 19 11:59:10 1984
***************
*** 5,10
  #include "signal.h"
  #include "stdio.h"
  #include "lrnref.h"
  
  wrapup(n)
  int n;

--- 5,13 -----
  #include "signal.h"
  #include "stdio.h"
  #include "lrnref.h"
+ #ifdef AXIOM
+ /* For restoring the terminal state when leaving. */
+ #include "sgtty.h"
  
  extern struct sgttyb save_terminal_state;
  #endif
***************
*** 6,11
  #include "stdio.h"
  #include "lrnref.h"
  
  wrapup(n)
  int n;
  {

--- 9,17 -----
  /* For restoring the terminal state when leaving. */
  #include "sgtty.h"
  
+ extern struct sgttyb save_terminal_state;
+ #endif
+ 
  wrapup(n)
  int n;
  {
***************
*** 30,35
  	}
  	if (!n && todo)
  		printf("To take up where you left off type \"learn %s %s\".\n", sname, todo);
  	printf("Bye.\n");	/* not only does this reassure user but it
  				stalls for time while deleting directory */
  	fflush(stdout);

--- 36,48 -----
  	}
  	if (!n && todo)
  		printf("To take up where you left off type \"learn %s %s\".\n", sname, todo);
+ #ifdef AXIOM
+ 	/*
+ 	 * Leave the terminal the way we found it!
+ 	 * Steve Kramer 1/20/84
+ 	 */
+ 	 stty (fileno (stdin), &save_terminal_state);
+ #endif
  	printf("Bye.\n");	/* not only does this reassure user but it
  				stalls for time while deleting directory */
  	fflush(stdout);
-- 
	--steve kramer
	{allegra,genrad,ihnp4,utzoo,philabs,uw-beaver}!linus!axiom!smk	(UUCP)
	linus!axiom!smk@mitre-bedford					(MIL)