trap signals for "-serial mon:stdio"

With mon:stdio you can exit the VM by switching to the monitor and
sending the "quit" command.  It is then useful to pass Ctrl-C to the
VM instead of exiting.

This in turn lets us stop tying the default signal handling behavior
to -nographic, removing gratuitous differences between "-display none"
and "-nographic".

This patch changes behavior for "-display none -serial mon:stdio", as
expected, but not for "-display none -serial stdio".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1372868986-25988-1-git-send-email-mjt@msgid.tls.msk.ru
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/qemu-options.hx b/qemu-options.hx
index 137a39b7ad..7cc4d8ef25 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -842,7 +842,8 @@ STEXI
 Normally, QEMU uses SDL to display the VGA output. With this option,
 you can totally disable graphical output so that QEMU is a simple
 command line application. The emulated serial port is redirected on
-the console. Therefore, you can still use QEMU to debug a Linux kernel
+the console and muxed with the monitor (unless redirected elsewhere
+explicitly). Therefore, you can still use QEMU to debug a Linux kernel
 with a serial console.
 ETEXI
 
@@ -2485,14 +2486,15 @@ same as if you had specified @code{-serial tcp} except the unix domain socket
 @item mon:@var{dev_string}
 This is a special option to allow the monitor to be multiplexed onto
 another serial port.  The monitor is accessed with key sequence of
-@key{Control-a} and then pressing @key{c}. See monitor access
-@ref{pcsys_keys} in the -nographic section for more keys.
+@key{Control-a} and then pressing @key{c}.
 @var{dev_string} should be any one of the serial devices specified
 above.  An example to multiplex the monitor onto a telnet server
 listening on port 4444 would be:
 @table @code
 @item -serial mon:telnet::4444,server,nowait
 @end table
+When monitor is multiplexed to stdio this way, Ctrl+C will not terminate
+QEMU anymore but will be passed to the guest instead.
 
 @item braille
 Braille device.  This will use BrlAPI to display the braille output on a real