terminal-unix: avoid data race + simplify

tio_orig and tio_orig_set are being touched inside of signal handler
which might be invoked from another thread - which makes this a data
race.

there's no real reason to set tio_orig inside of do_activate_getch2()
which is registered as a signal handler. just set it once, in
terminal_init(), before any signal handlers come in play.

this also allows removing the tio_orig_set variable completely.

1 files changed, 4 insertions, 13 deletions

diff --git a/osdep/terminal-unix.c b/osdep/terminal-unix.c
index 0ad3729eda..8e96af3928 100644
--- a/osdep/terminal-unix.c
+++ b/osdep/terminal-unix.c
@@ -51,8 +51,7 @@
 // buffer all keypresses until ENTER is pressed.
 #define INPUT_TIMEOUT 1000
 
-static volatile struct termios tio_orig;
-static volatile int tio_orig_set;
+static struct termios tio_orig;
 
 static int tty_in = -1, tty_out = -1;
 
@@ -300,11 +299,6 @@ static void do_activate_getch2(void)
     struct termios tio_new;
     tcgetattr(tty_in,&tio_new);
 
-    if (!tio_orig_set) {
-        tio_orig = tio_new;
-        tio_orig_set = 1;
-    }
-
     tio_new.c_lflag &= ~(ICANON|ECHO); /* Clear ICANON and ECHO. */
     tio_new.c_cc[VMIN] = 1;
     tio_new.c_cc[VTIME] = 0;
@@ -319,12 +313,7 @@ static void do_deactivate_getch2(void)
         return;
 
     enable_kx(false);
-
-    if (tio_orig_set) {
-        // once set, it will never be set again
-        // so we can cast away volatile here
-        tcsetattr(tty_in, TCSANOW, (const struct termios *) &tio_orig);
-    }
+    tcsetattr(tty_in, TCSANOW, &tio_orig);
 
     getch2_active = 0;
 }
@@ -552,6 +541,8 @@ void terminal_init(void)
         tty_out = STDOUT_FILENO;
     }
 
+    tcgetattr(tty_in, &tio_orig);
+
     // handlers to fix terminal settings
     setsigaction(SIGCONT, continue_sighandler, 0, true);
     setsigaction(SIGTSTP, stop_sighandler, SA_RESETHAND, false);