Restore tty attributes if interactive child is terminated by signal

Some programs like su(1) do not restore tty attributes like ECHO when they are
terminated by receiving SIGINT. Other shells (bash, mksh, zsh) save tty
attributes before executing an external command and restore them if the child
exited due to the receipt of a signal. rc now does the same if it is
interactive.

1 files changed, 7 insertions, 0 deletions

diff --git a/exec.c b/exec.c
index 6e90263..b9a1087 100644
--- a/exec.c
+++ b/exec.c
@@ -4,6 +4,8 @@
 
 #include <errno.h>
 #include <signal.h>
+#include <termios.h>
+#include <unistd.h>
 
 #include "wait.h"
 
@@ -19,6 +21,7 @@ extern void exec(List *s, bool parent) {
 	builtin_t *b;
 	char *path = NULL;
 	bool didfork, returning, saw_exec, saw_builtin;
+	struct termios t;
 	av = list2array(s, dashex);
 	saw_builtin = saw_exec = FALSE;
 	do {
@@ -68,6 +71,8 @@ extern void exec(List *s, bool parent) {
 	   must fork no matter what.
 	 */
 	if ((parent && (b == NULL || redirq != NULL)) || outstanding_cmdarg()) {
+		if (interactive)
+			tcgetattr(0, &t);
 		pid = rc_fork();
 		didfork = TRUE;
 	} else {
@@ -110,6 +115,8 @@ extern void exec(List *s, bool parent) {
 	default:
 		redirq = NULL;
 		rc_wait4(pid, &stat, TRUE);
+		if (interactive && WIFSIGNALED(stat))
+			tcsetattr(0, TCSANOW, &t);
 		setstatus(-1, stat);
 		/*
 		   There is a very good reason for having this weird