Patch for Busybox 1.25.1 to add RS-485 configuration to stty

BusyBox-stty-Add-RS485-config-options.patch

From: Clemens Gruber <clemens.gruber@pqgruber.com>
Date: Thu, 4 Aug 2016 14:51:44 +0200
Subject: [PATCH] stty: RS-485 support

Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
---
 coreutils/stty.c | 159 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 150 insertions(+), 9 deletions(-)

diff --git a/coreutils/stty.c b/coreutils/stty.c
index 52967ea8f351..5a2d44c7e790 100644
--- a/coreutils/stty.c
+++ b/coreutils/stty.c
@@ -19,6 +19,9 @@
 
    Special for busybox ported by Vladimir Oleynik <dzo@simtreas.ru> 2001
 
+   RS485 options added by Janos Angeli <angelo@angelo.hu> 2013
+   Adapted by Clemens Gruber <clemens.gruber@pqgruber.com> 2014-2016
+
    */
 
 //usage:#define stty_trivial_usage
@@ -32,8 +35,13 @@
 //usage:     "\n	[SETTING]	See manpage"
 
 #include "libbb.h"
+
 #include "common_bufsiz.h"
 
+#include <asm-generic/ioctls.h>
+#include <linux/ioctl.h>
+#include <linux/serial.h>
+
 #ifndef _POSIX_VDISABLE
 # define _POSIX_VDISABLE ((unsigned char) 0)
 #endif
@@ -933,11 +941,27 @@ static int find_param(const char *name)
 	return i;
 }
 
-static int recover_mode(const char *arg, struct termios *mode)
+static int find_rs485config(const char *name)
+{
+	static const char params[] ALIGN1 =
+		"rs485\0"		/* 1 */
+		"rs485rtsonsend\0"	/* 2 */
+		"rs485rtsaftersend\0"	/* 3 */
+		"rs485rxduringtx\0"	/* 4 */
+		"rs485delaybefore\0"	/* 5 */
+		"rs485delayafter\0";	/* 6 */
+	int i = index_in_strings(params, name) + 1;
+	if ((i == 5) || (i == 6))
+		i |= 0x80;
+	return i;
+}
+
+static int recover_mode(const char *arg, struct termios *mode, struct serial_rs485 *rs485conf, int paramcheck, int rs485)
 {
 	int i, n;
 	unsigned chr;
 	unsigned long iflag, oflag, cflag, lflag;
+	unsigned long rsflags, rsdelaybefore, rsdelayafter;
 
 	/* Scan into temporaries since it is too much trouble to figure out
 	   the right format for 'tcflag_t' */
@@ -956,15 +980,30 @@ static int recover_mode(const char *arg, struct termios *mode)
 		arg += n;
 	}
 
+	if (rs485 >= 0) {
+		if (sscanf(arg, ":%lx:%lx:%lx%n", &rsflags, &rsdelaybefore, &rsdelayafter, &n) != 3)
+			return 0;
+		rs485conf->flags = rsflags;
+		rs485conf->delay_rts_before_send = rsdelaybefore;
+		rs485conf->delay_rts_after_send = rsdelayafter;
+		arg += n;
+	}
+
 	/* Fail if there are too many fields */
-	if (*arg != '\0')
+	if (*arg != '\0') {
+		/* In the first pass of params verify we don't know the port device
+		   have RS485 support or not, so give a try for the extra RS485 params */
+		if ((paramcheck) && (sscanf(arg, ":%lx:%lx:%lx%n", &rsflags, &rsdelaybefore, &rsdelayafter, &n) == 3))
+			return 1;
+
 		return 0;
+	}
 
 	return 1;
 }
 
 static void display_recoverable(const struct termios *mode,
-				int UNUSED_PARAM dummy)
+				const struct serial_rs485 *rs485conf, int UNUSED_PARAM dummy, int rs485)
 {
 	int i;
 	printf("%lx:%lx:%lx:%lx",
@@ -972,6 +1011,14 @@ static void display_recoverable(const struct termios *mode,
 		   (unsigned long) mode->c_cflag, (unsigned long) mode->c_lflag);
 	for (i = 0; i < NCCS; ++i)
 		printf(":%x", (unsigned int) mode->c_cc[i]);
+
+	if (rs485 >= 0) {
+		printf(":%lx:%lx:%lx",
+			(unsigned long) rs485conf->flags,
+			(unsigned long) rs485conf->delay_rts_before_send,
+			(unsigned long) rs485conf->delay_rts_after_send);
+	}
+
 	bb_putchar('\n');
 }
 
@@ -992,7 +1039,7 @@ static void display_speed(const struct termios *mode, int fancy)
 	wrapf(fmt_str, tty_baud_to_value(ispeed), tty_baud_to_value(ospeed));
 }
 
-static void do_display(const struct termios *mode, int all)
+static void do_display(const struct termios *mode, const struct serial_rs485 *rs485conf, int all, int rs485)
 {
 	int i;
 	tcflag_t *bitsp;
@@ -1058,6 +1105,24 @@ static void do_display(const struct termios *mode, int all)
 		}
 	}
 	newline();
+
+	if (rs485 < 0) {
+		if (all) {
+			wrapf("RS485 not supported");
+			newline();
+		}
+	} else {
+		wrapf("%srs485 %srs485rtsonsend %srs485rtsaftersend %srs485rxduringtx",
+			(rs485conf->flags & SER_RS485_ENABLED) ? "" : "-",
+			(rs485conf->flags & SER_RS485_RTS_ON_SEND) ? "" : "-",
+			(rs485conf->flags & SER_RS485_RTS_AFTER_SEND) ? "" : "-",
+			(rs485conf->flags & SER_RS485_RX_DURING_TX) ? "" : "-");
+		newline();
+		wrapf("rs485delaybefore = %d; rs485delayafter = %d;\n",
+			rs485conf->delay_rts_before_send,
+			rs485conf->delay_rts_after_send);
+		newline();
+	}
 }
 
 static void sane_mode(struct termios *mode)
@@ -1252,11 +1317,14 @@ int stty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int stty_main(int argc UNUSED_PARAM, char **argv)
 {
 	struct termios mode;
-	void (*output_func)(const struct termios *, int);
+	struct serial_rs485 rs485conf;
+	void (*output_func)(const struct termios *, const struct serial_rs485 *, int, int);
 	const char *file_name = NULL;
 	int display_all = 0;
 	int stty_state;
 	int k;
+	int rs485_supported;
+	int rs485_setconfig;
 
 	INIT_G();
 
@@ -1281,6 +1349,13 @@ int stty_main(int argc UNUSED_PARAM, char **argv)
 				stty_state &= ~STTY_noargs;
 				continue;
 			}
+
+			param = find_rs485config(arg+1);
+			if ((param) && ((param & param_need_arg) == 0)) {
+				stty_state &= ~STTY_noargs;
+				continue;
+			}
+
 			/* It is an option - parse it */
 			i = 0;
 			while (arg[++i]) {
@@ -1335,6 +1410,17 @@ int stty_main(int argc UNUSED_PARAM, char **argv)
 			continue;
 		}
 
+		param = find_rs485config(arg);
+		if (param & param_need_arg) {
+			if (!argnext)
+				bb_error_msg_and_die(bb_msg_requires_arg, arg);
+			++k;
+		}
+		if (param) {
+			stty_state &= ~STTY_noargs;
+			continue;
+		}
+
 		param = find_param(arg);
 		if (param & param_need_arg) {
 			if (!argnext)
@@ -1369,7 +1455,7 @@ int stty_main(int argc UNUSED_PARAM, char **argv)
 			set_speed_or_die(output_speed, argnext, &mode);
 			break;
 		default:
-			if (recover_mode(arg, &mode) == 1) break;
+			if (recover_mode(arg, &mode, &rs485conf, 1, -1) == 1) break;
 			if (tty_value_to_baud(xatou(arg)) != (speed_t) -1) break;
  invalid_argument:
 			bb_error_msg_and_die("invalid argument '%s'", arg);
@@ -1402,15 +1488,17 @@ int stty_main(int argc UNUSED_PARAM, char **argv)
 	memset(&mode, 0, sizeof(mode));
 	if (tcgetattr(STDIN_FILENO, &mode))
 		perror_on_device_and_die("%s");
+	rs485_supported = ioctl(STDIN_FILENO, TIOCGRS485, &rs485conf);
 
 	if (stty_state & (STTY_verbose_output | STTY_recoverable_output | STTY_noargs)) {
 		G.max_col = get_terminal_width(STDOUT_FILENO);
-		output_func(&mode, display_all);
+		output_func(&mode, &rs485conf, display_all, rs485_supported);
 		return EXIT_SUCCESS;
 	}
 
 	/* Second pass: perform actions */
 	k = 0;
+	rs485_setconfig = 0;
 	while (argv[++k]) {
 		const struct mode_info *mp;
 		const struct control_info *cp;
@@ -1424,6 +1512,25 @@ int stty_main(int argc UNUSED_PARAM, char **argv)
 				set_mode(mp, 1 /* reversed */, &mode);
 				stty_state |= STTY_require_set_attr;
 			}
+
+			param = find_rs485config(arg+1);
+			if ((param) && ((param & param_need_arg) == 0)) {
+				rs485_setconfig = 1;
+				switch (param) {
+					case 1:
+						rs485conf.flags &= ~SER_RS485_ENABLED;
+						break;
+					case 2:
+						rs485conf.flags &= ~SER_RS485_RTS_ON_SEND;
+						break;
+					case 3:
+						rs485conf.flags &= ~SER_RS485_RTS_AFTER_SEND;
+						break;
+					case 4:
+						rs485conf.flags &= ~SER_RS485_RX_DURING_TX;
+				}
+			}
+
 			/* It is an option - already parsed. Skip it */
 			continue;
 		}
@@ -1443,6 +1550,33 @@ int stty_main(int argc UNUSED_PARAM, char **argv)
 			continue;
 		}
 
+		param = find_rs485config(arg);
+		if (param) {
+			rs485_setconfig = 1;
+			if (param & param_need_arg)
+				++k;
+			switch (param & 0x7F) {
+				case 1:
+					rs485conf.flags |= SER_RS485_ENABLED;
+					break;
+				case 2:
+					rs485conf.flags |= SER_RS485_RTS_ON_SEND;
+					break;
+				case 3:
+					rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
+					break;
+				case 4:
+					rs485conf.flags |= SER_RS485_RX_DURING_TX;
+					break;
+				case 5:
+					rs485conf.delay_rts_before_send = xatoul_sfx(argnext, stty_suffixes);
+					break;
+				case 6:
+					rs485conf.delay_rts_after_send = xatoul_sfx(argnext, stty_suffixes);
+			}
+			continue;
+		}
+
 		param = find_param(arg);
 		if (param & param_need_arg) {
 			++k;
@@ -1479,9 +1613,11 @@ int stty_main(int argc UNUSED_PARAM, char **argv)
 			stty_state |= (STTY_require_set_attr | STTY_speed_was_set);
 			break;
 		default:
-			if (recover_mode(arg, &mode) == 1)
+			if (recover_mode(arg, &mode, &rs485conf, 0, rs485_supported) == 1) {
 				stty_state |= STTY_require_set_attr;
-			else /* true: if (tty_value_to_baud(xatou(arg)) != (speed_t) -1) */{
+				if (rs485_supported >= 0)
+					rs485_setconfig = 1;
+			} else /* true: if (tty_value_to_baud(xatou(arg)) != (speed_t) -1) */{
 				set_speed_or_die(both_speeds, arg, &mode);
 				stty_state |= (STTY_require_set_attr | STTY_speed_was_set);
 			} /* else - impossible (caught in the first pass):
@@ -1532,5 +1668,10 @@ int stty_main(int argc UNUSED_PARAM, char **argv)
 		}
 	}
 
+	if (rs485_setconfig) {
+		if (ioctl (STDIN_FILENO, TIOCSRS485, &rs485conf) < 0)
+			perror_on_device_and_die("%s: cannot set RS485 options");
+	}
+
 	return EXIT_SUCCESS;
 }
-- 
2.11.0