terminal-unix: fix race condition with tty reset

Calling do_deactivate_getch2 before joining the terminal thread could
lead to breakage if the terminal thread got another interation in before
it was signaled to stop.

This also addresses a minor error with the order in which things are
initialized - getch2_poll would previously call tcgetpgrp(tty_in) before
tty_in was initialized, which did not lead to broken behavior, but was
not correct either.

Fixes #5195

1 files changed, 10 insertions, 10 deletions

diff --git a/osdep/terminal-unix.c b/osdep/terminal-unix.c
index 0eca44372e..1e909522b7 100644
--- a/osdep/terminal-unix.c
+++ b/osdep/terminal-unix.c
@@ -45,7 +45,7 @@
 static volatile struct termios tio_orig;
 static volatile int tio_orig_set;
 
-static int tty_in, tty_out;
+static int tty_in = -1, tty_out = -1;
 
 struct key_entry {
     const char *seq;
@@ -417,12 +417,6 @@ void terminal_setup_getch(struct input_ctx *ictx)
     if (mp_make_wakeup_pipe(death_pipe) < 0)
         return;
 
-    tty_in = tty_out = open("/dev/tty", O_RDWR | O_CLOEXEC);
-    if (tty_in < 0) {
-        tty_in = STDIN_FILENO;
-        tty_out = STDOUT_FILENO;
-    }
-
     // Disable reading from the terminal even if stdout is not a tty, to make
     //   mpv ... | less
     // do the right thing.
@@ -456,16 +450,16 @@ void terminal_uninit(void)
     setsigaction(SIGTTIN, SIG_DFL, 0, false);
     setsigaction(SIGTTOU, SIG_DFL, 0, false);
 
-    do_deactivate_getch2();
-
     if (input_ctx) {
         (void)write(death_pipe[1], &(char){0}, 1);
         pthread_join(input_thread, NULL);
         close_death_pipe();
-        close_tty();
         input_ctx = NULL;
     }
 
+    do_deactivate_getch2();
+    close_tty();
+
     getch2_enabled = 0;
     read_terminal = false;
 }
@@ -490,6 +484,12 @@ void terminal_init(void)
     assert(!getch2_enabled);
     getch2_enabled = 1;
 
+    tty_in = tty_out = open("/dev/tty", O_RDWR | O_CLOEXEC);
+    if (tty_in < 0) {
+        tty_in = STDIN_FILENO;
+        tty_out = STDOUT_FILENO;
+    }
+
     // handlers to fix terminal settings
     setsigaction(SIGCONT, continue_sighandler, 0, true);
     setsigaction(SIGTSTP, stop_sighandler, SA_RESETHAND, false);