From 9f32047b6512fb261f5b57f62571b658ba6e3330 Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@member.fsf.org>
Date: Sat, 7 Nov 2020 01:21:29 +0200
Subject: [PATCH] restore serial port settings on exit

---
 src/sball.c |   71 ++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 41 insertions(+), 30 deletions(-)

diff --git a/src/sball.c b/src/sball.c
index 3273480..9dce2ae 100644
--- a/src/sball.c
+++ b/src/sball.c
@@ -4,7 +4,6 @@
 #include <ctype.h>
 #include <time.h>
 #include <errno.h>
-#include <alloca.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <termios.h>
@@ -30,11 +29,16 @@ struct sball {
 	short mot[6];
 	unsigned int keystate;
 
+	struct termios saved_term;
+	int saved_mstat;
+
 	int (*parse)(struct sball*, int, char*, int);
 };
 
-static int stty_sball(int fd);
-static int stty_mag(int fd);
+static int stty_sball(struct sball *sb);
+static int stty_mag(struct sball *sb);
+static void stty_save(struct sball *sb);
+static void stty_restore(struct sball *sb);
 
 static int proc_input(struct sball *sb);
 
@@ -68,7 +72,9 @@ struct sball *sball_open(const char *dev)
 	sb->flags = 0;
 	sb->len = 0;
 
-	if(stty_sball(fd) == -1) {
+	stty_save(sb);
+
+	if(stty_sball(sb) == -1) {
 		goto err;
 	}
 	write(fd, "\r@RESET\r", 8);
@@ -89,7 +95,7 @@ struct sball *sball_open(const char *dev)
 	}
 
 	/* try as a magellan spacemouse */
-	if(stty_mag(fd) == -1) {
+	if(stty_mag(sb) == -1) {
 		goto err;
 	}
 	write(fd, "vQ\r", 3);
@@ -109,6 +115,7 @@ struct sball *sball_open(const char *dev)
 	}
 
 err:
+	stty_restore(sb);
 	close(fd);
 	free(sb);
 	return 0;
@@ -117,6 +124,8 @@ err:
 void sball_close(struct sball *sb)
 {
 	if(!sb) return;
+
+	stty_restore(sb);
 	close(sb->fd);
 }
 
@@ -161,16 +170,12 @@ int sball_num_buttons(struct sball *sb)
 }
 
 /* Labtec spaceball: 9600 8n1 XON/XOFF */
-static int stty_sball(int fd)
+static int stty_sball(struct sball *sb)
 {
-	int status;
+	int mstat;
 	struct termios term;
 
-	if(tcgetattr(fd, &term) == -1) {
-		perror("sball_open: tcgetattr");
-		return -1;
-	}
-
+	term = sb->saved_term;
 	term.c_oflag = 0;
 	term.c_lflag = ICANON;
 	term.c_cc[VMIN] = 0;
@@ -187,29 +192,24 @@ static int stty_sball(int fd)
 	cfsetispeed(&term, B9600);
 	cfsetospeed(&term, B9600);
 
-	if(tcsetattr(fd, TCSANOW, &term) == -1) {
+	if(tcsetattr(sb->fd, TCSAFLUSH, &term) == -1) {
 		perror("sball_open: tcsetattr");
 		return -1;
 	}
+	tcflush(sb->fd, TCIOFLUSH);
 
-	if(ioctl(fd, TIOCMGET, &status) != -1) {
-		status |= TIOCM_DTR | TIOCM_RTS;
-		ioctl(fd, TIOCMSET, &status);
-	}
+	mstat = sb->saved_mstat | TIOCM_DTR | TIOCM_RTS;
+	ioctl(sb->fd, TIOCMGET, &mstat);
 	return 0;
 }
 
 /* Logicad magellan spacemouse: 9600 8n2 CTS/RTS */
-static int stty_mag(int fd)
+static int stty_mag(struct sball *sb)
 {
-	int status;
+	int mstat;
 	struct termios term;
 
-	if(tcgetattr(fd, &term) == -1) {
-		perror("sball_open: tcgetattr");
-		return -1;
-	}
-
+	term = sb->saved_term;
 	term.c_oflag = 0;
 	term.c_lflag = ICANON;
 	term.c_cc[VMIN] = 0;
@@ -226,19 +226,30 @@ static int stty_mag(int fd)
 	cfsetispeed(&term, B9600);
 	cfsetospeed(&term, B9600);
 
-	if(tcsetattr(fd, TCSAFLUSH, &term) == -1) {
+	if(tcsetattr(sb->fd, TCSAFLUSH, &term) == -1) {
 		perror("sball_open: tcsetattr");
 		return -1;
 	}
-	tcflush(fd, TCIOFLUSH);
+	tcflush(sb->fd, TCIOFLUSH);
 
-	if(ioctl(fd, TIOCMGET, &status) != -1) {
-		status |= TIOCM_DTR | TIOCM_RTS;
-		ioctl(fd, TIOCMGET, &status);
-	}
+	mstat = sb->saved_mstat | TIOCM_DTR | TIOCM_RTS;
+	ioctl(sb->fd, TIOCMGET, &mstat);
 	return 0;
 }
 
+static void stty_save(struct sball *sb)
+{
+	tcgetattr(sb->fd, &sb->saved_term);
+	ioctl(sb->fd, TIOCMGET, &sb->saved_mstat);
+}
+
+static void stty_restore(struct sball *sb)
+{
+	tcsetattr(sb->fd, TCSAFLUSH, &sb->saved_term);
+	tcflush(sb->fd, TCIOFLUSH);
+	ioctl(sb->fd, TIOCMSET, &sb->saved_mstat);
+}
+
 
 static int proc_input(struct sball *sb)
 {
-- 
1.7.10.4