chardev/char-win-stdio: Pass Ctrl+C to guest with a multiplexed monitor

At present when pressing Ctrl+C from a guest running on QEMU Windows
with a multiplexed monitor, e.g.: -serial mon:stdio, QEMU executable
just exits. This behavior is inconsistent with the Linux version.

Such behavior is caused by unconditionally setting the input mode
ENABLE_PROCESSED_INPUT for a console's input buffer. Fix this by
testing whether the chardev is allowed to do so.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20221025141015.612291-1-bin.meng@windriver.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/chardev/char-win-stdio.c b/chardev/char-win-stdio.c
index a4771ab82e..eb830eabd9 100644
--- a/chardev/char-win-stdio.c
+++ b/chardev/char-win-stdio.c
@@ -146,6 +146,8 @@ static void qemu_chr_open_stdio(Chardev *chr,
                                 bool *be_opened,
                                 Error **errp)
 {
+    ChardevStdio *opts = backend->u.stdio.data;
+    bool stdio_allow_signal = !opts->has_signal || opts->signal;
     WinStdioChardev *stdio = WIN_STDIO_CHARDEV(chr);
     DWORD              dwMode;
     int                is_console = 0;
@@ -193,7 +195,11 @@ static void qemu_chr_open_stdio(Chardev *chr,
     if (is_console) {
         /* set the terminal in raw mode */
         /* ENABLE_QUICK_EDIT_MODE | ENABLE_EXTENDED_FLAGS */
-        dwMode |= ENABLE_PROCESSED_INPUT;
+        if (stdio_allow_signal) {
+            dwMode |= ENABLE_PROCESSED_INPUT;
+        } else {
+            dwMode &= ~ENABLE_PROCESSED_INPUT;
+        }
     }
 
     SetConsoleMode(stdio->hStdIn, dwMode);