degesch: better SIGTSTP handling

1 files changed, 23 insertions, 2 deletions

diff --git a/degesch.c b/degesch.c
index f535170..a42682a 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1371,6 +1371,7 @@ struct app_context
 	struct str input_buffer;            ///< Buffered pasted content
 
 	bool running_backlog_helper;        ///< Running a backlog helper
+	int terminal_suspended;             ///< Terminal suspension level
 }
 *g_ctx;
 
@@ -8984,6 +8985,10 @@ toggle_bracketed_paste (bool enable)
 static void
 suspend_terminal (struct app_context *ctx)
 {
+	// Terminal can get suspended by both backlog helper and SIGTSTP handling
+	if (ctx->terminal_suspended++ > 0)
+		return;
+
 #ifdef HAVE_READLINE
 	rl_deprep_terminal ();
 #elif defined (HAVE_EDITLINE)
@@ -8999,6 +9004,9 @@ suspend_terminal (struct app_context *ctx)
 static void
 resume_terminal (struct app_context *ctx)
 {
+	if (--ctx->terminal_suspended > 0)
+		return;
+
 #ifdef HAVE_READLINE
 	rl_prep_terminal (true);
 #elif defined (HAVE_EDITLINE)
@@ -9760,6 +9768,9 @@ signal_superhandler (int signum)
 	case SIGCHLD:
 		postpone_signal_handling ('c');
 		break;
+	case SIGTSTP:
+		postpone_signal_handling ('s');
+		break;
 	default:
 		hard_assert (!"unhandled signal");
 	}
@@ -9795,6 +9806,7 @@ setup_signal_handlers (void)
 	if (sigaction (SIGWINCH, &sa, NULL) == -1
 	 || sigaction (SIGINT,   &sa, NULL) == -1
 	 || sigaction (SIGTERM,  &sa, NULL) == -1
+	 || sigaction (SIGTSTP,  &sa, NULL) == -1
 	 || sigaction (SIGCHLD,  &sa, NULL) == -1)
 		exit_fatal ("sigaction: %s", strerror (errno));
 }
@@ -9844,8 +9856,17 @@ try_reap_child (struct app_context *ctx)
 static void
 on_signal_pipe_readable (const struct pollfd *fd, struct app_context *ctx)
 {
-	char dummy;
-	(void) read (fd->fd, &dummy, 1);
+	char id = 0;
+	(void) read (fd->fd, &id, 1);
+
+	// Stop ourselves cleanly, even if it makes little sense to do this
+	if (id == 's')
+	{
+		suspend_terminal (ctx);
+		kill (getpid (), SIGSTOP);
+		g_winch_received = true;
+		resume_terminal (ctx);
+	}
 
 	// Reap all dead children (since the signal pipe may overflow etc. we run
 	// waitpid() in a loop to return all the zombies it knows about).