Add clear-screen emacs editing command, currently not bound to a

key by default.  The shell will query the terminfo database to
find the escape sequence to clear the screen.  OK deraadt@

7 files changed, 72 insertions, 17 deletions

diff --git a/bin/ksh/Makefile b/bin/ksh/Makefile
index 66419f2311d..621c38bcfd0 100644
--- a/bin/ksh/Makefile
+++ b/bin/ksh/Makefile
@@ -1,6 +1,9 @@
-#	$OpenBSD: Makefile,v 1.38 2018/01/06 16:28:58 millert Exp $
+#	$OpenBSD: Makefile,v 1.39 2018/06/18 17:03:58 millert Exp $
 
 PROG=	ksh
+DPADD+=	${LIBCURSES}
+LDADD+=	-lcurses
+
 SRCS=	alloc.c c_ksh.c c_sh.c c_test.c c_ulimit.c edit.c emacs.c eval.c \
 	exec.c expr.c history.c io.c jobs.c lex.c mail.c main.c \
 	misc.c path.c shf.c syn.c table.c trap.c tree.c tty.c var.c \
diff --git a/bin/ksh/edit.c b/bin/ksh/edit.c
index 42514b9ec76..bbb1b3aeb8f 100644
--- a/bin/ksh/edit.c
+++ b/bin/ksh/edit.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: edit.c,v 1.65 2018/04/09 17:53:36 tobias Exp $	*/
+/*	$OpenBSD: edit.c,v 1.66 2018/06/18 17:03:58 millert Exp $	*/
 
 /*
  * Command line editing - common code
@@ -138,10 +138,10 @@ x_flush(void)
 	shf_flush(shl_out);
 }
 
-void
+int
 x_putc(int c)
 {
-	shf_putc(c, shl_out);
+	return shf_putc(c, shl_out);
 }
 
 void
diff --git a/bin/ksh/edit.h b/bin/ksh/edit.h
index 41b411e8935..0b604cd64fb 100644
--- a/bin/ksh/edit.h
+++ b/bin/ksh/edit.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: edit.h,v 1.11 2016/01/26 17:39:31 mmcc Exp $	*/
+/*	$OpenBSD: edit.h,v 1.12 2018/06/18 17:03:58 millert Exp $	*/
 
 /* NAME:
  *      edit.h - globals for edit modes
@@ -37,7 +37,7 @@ extern X_chars edchars;
 /* edit.c */
 int	x_getc(void);
 void	x_flush(void);
-void	x_putc(int);
+int	x_putc(int);
 void	x_puts(const char *);
 bool	x_mode(bool);
 int	promptlen(const char *, const char **);
diff --git a/bin/ksh/emacs.c b/bin/ksh/emacs.c
index b88219d7440..dd5875c1a10 100644
--- a/bin/ksh/emacs.c
+++ b/bin/ksh/emacs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: emacs.c,v 1.84 2018/01/16 17:17:18 jca Exp $	*/
+/*	$OpenBSD: emacs.c,v 1.85 2018/06/18 17:03:58 millert Exp $	*/
 
 /*
  *  Emacs-like command line editing and history
@@ -21,6 +21,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#ifndef SMALL
+# include <term.h>
+# include <curses.h>
+#endif
 
 #include "sh.h"
 #include "edit.h"
@@ -28,6 +32,7 @@
 static	Area	aedit;
 #define	AEDIT	&aedit		/* area for kill ring and macro defns */
 
+#undef CTRL
 #define	CTRL(x)		((x) == '?' ? 0x7F : (x) & 0x1F)	/* ASCII */
 #define	UNCTRL(x)	((x) == 0x7F ? '?' : (x) | 0x40)	/* ASCII */
 
@@ -146,6 +151,7 @@ static int	isu8cont(unsigned char);
 /* proto's for keybindings */
 static int	x_abort(int);
 static int	x_beg_hist(int);
+static int	x_clear_screen(int);
 static int	x_comp_comm(int);
 static int	x_comp_file(int);
 static int	x_complete(int);
@@ -202,6 +208,7 @@ static int	x_debug_info(int);
 static const struct x_ftab x_ftab[] = {
 	{ x_abort,		"abort",			0 },
 	{ x_beg_hist,		"beginning-of-history",		0 },
+	{ x_clear_screen,	"clear-screen",			0 },
 	{ x_comp_comm,		"complete-command",		0 },
 	{ x_comp_file,		"complete-file",		0 },
 	{ x_complete,		"complete",			0 },
@@ -1004,12 +1011,19 @@ x_draw_line(int c)
 {
 	x_redraw(-1);
 	return KSTD;
+}
 
+static int
+x_clear_screen(int c)
+{
+	x_redraw(-2);
+	return KSTD;
 }
 
-/* Redraw (part of) the line.  If limit is < 0, the everything is redrawn
- * on a NEW line, otherwise limit is the screen column up to which needs
- * redrawing.
+/* Redraw (part of) the line.
+ * A non-negative limit is the screen column up to which needs
+ * redrawing. A limit of -1 redraws on a new line, while a limit
+ * of -2 (attempts to) clear the screen.
  */
 static void
 x_redraw(int limit)
@@ -1018,9 +1032,20 @@ x_redraw(int limit)
 	char	*cp;
 
 	x_adj_ok = 0;
-	if (limit == -1)
+	if (limit == -2) {
+		int cleared = 0;
+#ifndef SMALL
+		if (cur_term != NULL && clear_screen != NULL) {
+			if (tputs(clear_screen, 1, x_putc) != ERR)
+				cleared = 1;
+		}
+#endif
+		if (!cleared)
+			x_e_putc('\n');
+	}
+	else if (limit == -1)
 		x_e_putc('\n');
-	else
+	else if (limit >= 0)
 		x_e_putc('\r');
 	x_flush();
 	if (xbp == xbuf) {
diff --git a/bin/ksh/ksh.1 b/bin/ksh/ksh.1
index 3d50e753d6d..5dcefe1d456 100644
--- a/bin/ksh/ksh.1
+++ b/bin/ksh/ksh.1
@@ -1,8 +1,8 @@
-.\"	$OpenBSD: ksh.1,v 1.200 2018/05/30 21:20:52 benno Exp $
+.\"	$OpenBSD: ksh.1,v 1.201 2018/06/18 17:03:58 millert Exp $
 .\"
 .\"	Public Domain
 .\"
-.Dd $Mdocdate: May 30 2018 $
+.Dd $Mdocdate: June 18 2018 $
 .Dt KSH 1
 .Os
 .Sh NAME
@@ -1717,6 +1717,10 @@ loops to store the value that is read from standard input.
 The number of seconds since the shell started or, if the parameter has been
 assigned an integer value, the number of seconds since the assignment plus the
 value that was assigned.
+.It Ev TERM
+The user's terminal type.
+If set, it will be used to determine the escape sequence used to
+clear the screen.
 .It Ev TMOUT
 If set to a positive integer in an interactive shell, it specifies the maximum
 number of seconds the shell will wait for input after printing the primary
@@ -4690,6 +4694,11 @@ Moves the cursor to the beginning of the edited input line.
 Uppercase the first character in the next
 .Ar n
 words, leaving the cursor past the end of the last word.
+.It clear-screen:
+Clears the screen if the
+.Ev TERM
+parameter is set and the terminal supports clearing the screen, then
+reprints the prompt string and the current input line.
 .It comment: ^[#
 If the current line does not begin with a comment character, one is added at
 the beginning of the line and the line is entered (as if return had been
diff --git a/bin/ksh/table.h b/bin/ksh/table.h
index 04df8de2666..63762502259 100644
--- a/bin/ksh/table.h
+++ b/bin/ksh/table.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: table.h,v 1.14 2018/04/09 17:53:36 tobias Exp $	*/
+/*	$OpenBSD: table.h,v 1.15 2018/06/18 17:03:58 millert Exp $	*/
 
 /* $From: table.h,v 1.3 1994/05/31 13:34:34 michael Exp $ */
 
@@ -170,6 +170,7 @@ extern const struct builtin shbuiltins [], kshbuiltins [];
 #define	V_TMOUT			16
 #define	V_TMPDIR		17
 #define	V_LINENO		18
+#define	V_TERM			19
 
 /* values for set_prompt() */
 #define PS1	0		/* command */
diff --git a/bin/ksh/var.c b/bin/ksh/var.c
index e3d8589aa96..846200a469c 100644
--- a/bin/ksh/var.c
+++ b/bin/ksh/var.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: var.c,v 1.68 2018/04/13 18:18:36 cheloha Exp $	*/
+/*	$OpenBSD: var.c,v 1.69 2018/06/18 17:03:58 millert Exp $	*/
 
 #include <sys/stat.h>
 #include <sys/time.h>
@@ -11,6 +11,10 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
+#ifndef SMALL
+# include <term.h>
+# include <curses.h>
+#endif
 
 #include "sh.h"
 
@@ -111,12 +115,13 @@ initvar(void)
 		{ "SECONDS",		V_SECONDS },
 		{ "TMOUT",		V_TMOUT },
 		{ "LINENO",		V_LINENO },
+		{ "TERM",		V_TERM },
 		{ NULL,	0 }
 	};
 	int i;
 	struct tbl *tp;
 
-	ktinit(&specials, APERM, 32); /* must be 2^n (currently 17 specials) */
+	ktinit(&specials, APERM, 32); /* must be 2^n (currently 19 specials) */
 	for (i = 0; names[i].name; i++) {
 		tp = ktenter(&specials, names[i].name, hash(names[i].name));
 		tp->flag = DEFINED|ISSET;
@@ -1057,6 +1062,18 @@ setspec(struct tbl *vp)
 		user_lineno = (unsigned int) intval(vp) - current_lineno - 1;
 		vp->flag |= SPECIAL;
 		break;
+	case V_TERM:
+#ifndef SMALL
+		{
+			int ret;
+
+			vp->flag &= ~SPECIAL;
+			if (setupterm(str_val(vp), STDOUT_FILENO, &ret) == ERR)
+				del_curterm(cur_term);
+			vp->flag |= SPECIAL;
+		}
+#endif
+		break;
 	}
 }