Add -E to change the escape character, from Artturi Alm.

no objections from deraadt, ok millert

4 files changed, 44 insertions, 24 deletions

diff --git a/usr.bin/cu/command.c b/usr.bin/cu/command.c
index c07fe73aeca..e826c659aad 100644
--- a/usr.bin/cu/command.c
+++ b/usr.bin/cu/command.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: command.c,v 1.16 2017/12/10 01:03:46 deraadt Exp $ */
+/* $OpenBSD: command.c,v 1.17 2019/03/22 07:03:23 nicm Exp $ */
 
 /*
  * Copyright (c) 2012 Nicholas Marriott <nicm@openbsd.org>
@@ -30,6 +30,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
+#include <vis.h>
 
 #include "cu.h"
 
@@ -223,6 +224,8 @@ start_record(void)
 void
 do_command(char c)
 {
+	char esc[4 + 1];
+
 	if (restricted && strchr("CRX$>", c) != NULL) {
 		cu_warnx("~%c command is not allowed in restricted mode", c);
 		return;
@@ -266,20 +269,23 @@ do_command(char c)
 		sleep(1);
 		ioctl(line_fd, TIOCCBRK, NULL);
 		break;
-	case '~':
-		bufferevent_write(line_ev, "~", 1);
+	default:
+		if ((u_char)c == escape_char)
+			bufferevent_write(line_ev, &c, 1);
 		break;
 	case '?':
+		vis(esc, escape_char, VIS_WHITE | VIS_NOSLASH, 0);
 		printf("\r\n"
-		    "~#      send break\r\n"
-		    "~$      pipe local command to remote host\r\n"
-		    "~>      send file to remote host\r\n"
-		    "~C      connect program to remote host\r\n"
-		    "~D      de-assert DTR line briefly\r\n"
-		    "~R      start recording to file\r\n"
-		    "~S      set speed\r\n"
-		    "~X      send file with XMODEM\r\n"
-		    "~?      get this summary\r\n"
+		    "%s#      send break\r\n"
+		    "%s$      pipe local command to remote host\r\n"
+		    "%s>      send file to remote host\r\n"
+		    "%sC      connect program to remote host\r\n"
+		    "%sD      de-assert DTR line briefly\r\n"
+		    "%sR      start recording to file\r\n"
+		    "%sS      set speed\r\n"
+		    "%sX      send file with XMODEM\r\n"
+		    "%s?      get this summary\r\n",
+		    esc, esc, esc, esc, esc, esc, esc, esc, esc
 		);
 		break;
 	}
diff --git a/usr.bin/cu/cu.1 b/usr.bin/cu/cu.1
index 104a6ea7893..5daab4bc074 100644
--- a/usr.bin/cu/cu.1
+++ b/usr.bin/cu/cu.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: cu.1,v 1.18 2018/08/05 06:11:55 jmc Exp $
+.\"	$OpenBSD: cu.1,v 1.19 2019/03/22 07:03:23 nicm Exp $
 .\"
 .\" Copyright (c) 1980, 1990, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -27,7 +27,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: August 5 2018 $
+.Dd $Mdocdate: March 22 2019 $
 .Dt CU 1
 .Os
 .Sh NAME
@@ -36,6 +36,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl dr
+.Op Fl E Ar escape_char
 .Op Fl l Ar line
 .Op Fl s Ar speed | Fl Ar speed
 .Nm
@@ -55,6 +56,8 @@ The options are as follows:
 Specify that the line is directly connected and
 .Nm
 should not allow the driver to block waiting for a carrier to be detected.
+.It Fl E Ar escape_char
+Specify an escape character to use instead of the default tilde.
 .It Fl l Ar line
 Specify the line to use.
 Either of the forms like
diff --git a/usr.bin/cu/cu.c b/usr.bin/cu/cu.c
index 03a2df4181f..697f72d3418 100644
--- a/usr.bin/cu/cu.c
+++ b/usr.bin/cu/cu.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cu.c,v 1.26 2017/12/10 01:03:46 deraadt Exp $ */
+/* $OpenBSD: cu.c,v 1.27 2019/03/22 07:03:23 nicm Exp $ */
 
 /*
  * Copyright (c) 2012 Nicholas Marriott <nicm@openbsd.org>
@@ -41,6 +41,7 @@ FILE			*record_file;
 struct termios		 saved_tio;
 struct bufferevent	*input_ev;
 struct bufferevent	*output_ev;
+int			 escape_char = '~';
 int			 is_direct = -1;
 int			 restricted = 0;
 const char		*line_path = NULL;
@@ -53,7 +54,7 @@ struct event		 sighup_ev;
 enum {
 	STATE_NONE,
 	STATE_NEWLINE,
-	STATE_TILDE
+	STATE_ESCAPE
 } last_state = STATE_NEWLINE;
 
 __dead void	usage(void);
@@ -67,8 +68,8 @@ void		try_remote(const char *, const char *, const char *);
 __dead void
 usage(void)
 {
-	fprintf(stderr, "usage: %s [-dr] [-l line] [-s speed | -speed]\n",
-	    __progname);
+	fprintf(stderr, "usage: %s [-dr] [-E escape_char] [-l line] "
+	    "[-s speed | -speed]\n", __progname);
 	fprintf(stderr, "       %s [host]\n", __progname);
 	exit(1);
 }
@@ -94,14 +95,14 @@ main(int argc, char **argv)
 	for (i = 1; i < argc; i++) {
 		if (strcmp("--", argv[i]) == 0)
 			break;
-		if (argv[i][0] != '-' || !isdigit((unsigned char)argv[i][1]))
+		if (argv[i][0] != '-' || !isdigit((u_char)argv[i][1]))
 			continue;
 
 		if (asprintf(&argv[i], "-s%s", &argv[i][1]) == -1)
 			errx(1, "speed asprintf");
 	}
 
-	while ((opt = getopt(argc, argv, "drl:s:")) != -1) {
+	while ((opt = getopt(argc, argv, "drE:l:s:")) != -1) {
 		switch (opt) {
 		case 'd':
 			is_direct = 1;
@@ -111,6 +112,15 @@ main(int argc, char **argv)
 				err(1, "pledge");
 			restricted = 1;
 			break;
+		case 'E':
+			if (optarg[0] == '^' && optarg[2] == '\0' &&
+			    (u_char)optarg[1] >= 64 && (u_char)optarg[1] < 128)
+				escape_char = (u_char)optarg[1] & 31;
+			else if (strlen(optarg) == 1)
+				escape_char = (u_char)optarg[0];
+			else
+				errx(1, "invalid escape character: %s", optarg);
+			break;
 		case 'l':
 			line_path = optarg;
 			break;
@@ -308,14 +318,14 @@ stream_read(struct bufferevent *bufev, void *data)
 				last_state = STATE_NEWLINE;
 			break;
 		case STATE_NEWLINE:
-			if (state_change && *ptr == '~') {
-				last_state = STATE_TILDE;
+			if (state_change && (u_char)*ptr == escape_char) {
+				last_state = STATE_ESCAPE;
 				continue;
 			}
 			if (*ptr != '\r')
 				last_state = STATE_NONE;
 			break;
-		case STATE_TILDE:
+		case STATE_ESCAPE:
 			do_command(*ptr);
 			last_state = STATE_NEWLINE;
 			continue;
diff --git a/usr.bin/cu/cu.h b/usr.bin/cu/cu.h
index 2a7ca45d414..9e3fb776857 100644
--- a/usr.bin/cu/cu.h
+++ b/usr.bin/cu/cu.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: cu.h,v 1.8 2017/12/10 01:03:46 deraadt Exp $ */
+/* $OpenBSD: cu.h,v 1.9 2019/03/22 07:03:23 nicm Exp $ */
 
 /*
  * Copyright (c) 2012 Nicholas Marriott <nicm@openbsd.org>
@@ -23,6 +23,7 @@
 void				 do_command(char);
 
 /* cu.c */
+extern int			 escape_char;
 extern int			 restricted;
 extern FILE			*record_file;
 extern struct termios		 saved_tio;