chat: do not die when HANGUP param is missing. Closes 10016

function                                             old     new   delta
chat_main                                           1356    1379     +23

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/miscutils/chat.c b/miscutils/chat.c
index 1446a040c..2dfe52c4f 100644
--- a/miscutils/chat.c
+++ b/miscutils/chat.c
@@ -238,10 +238,18 @@ int chat_main(int argc UNUSED_PARAM, char **argv)
                         , *argv
                 );
                 if (key >= 0) {
+                        bool onoff;
                         // cache directive value
                         char *arg = *++argv;
+
+                        if (!arg) {
+#if ENABLE_FEATURE_CHAT_TTY_HIFI
+                                tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
+#endif
+                                bb_show_usage();
+                        }
                         // OFF -> 0, anything else -> 1
-                        bool onoff = (0 != strcmp("OFF", arg));
+                        onoff = (0 != strcmp("OFF", arg));
                         // process directive
                         if (DIR_HANGUP == key) {
                                 // turn SIGHUP on/off