Commit ab51b1d5 authored by Michael Tokarev's avatar Michael Tokarev Committed by Anthony Liguori
Browse files

disallow -daemonize usage of stdio (curses display, -nographic, -serial stdio etc)

Curses display requires stdin/out to stay on the terminal,
so -daemonize makes no sense in this case.  Instead of
leaving display uninitialized like is done since 995ee2bf

explicitly detect this case earlier and error out.

-nographic can actually be used with -daemonize, by redirecting
everything to a null device, but the problem is that according
to documentation and historical behavour, -nographic redirects
guest ports to stdin/out, which, again, makes no sense in case
of -daemonize.  Since -nographic is a legacy option, don't bother
fixing this case (to allow -nographic and -daemonize by redirecting
guest ports to null instead of stdin/out in this case), but disallow
it completely instead, to stop garbling host terminal.

If no display display needed and user wants to use -nographic,
the right way to go is to use
  -serial null -parallel null -monitor none -display none -vga none
instead of -nographic.

Also prevent the same issue -- it was possible to get garbled
host tty after

  -nographic -daemonize

and it is still possible to have it by using

  -serial stdio -daemonize

Fix this by disallowing opening stdio chardev when -daemonize
is specified.
Signed-off-by: default avatarMichael Tokarev <>
Signed-off-by: default avatarAnthony Liguori <>
parent 217da7fd
......@@ -772,6 +772,10 @@ static CharDriverState *qemu_chr_open_stdio(QemuOpts *opts)
if (stdio_nb_clients >= STDIO_MAX_CLIENTS) {
return NULL;
if (is_daemonized()) {
error_report("cannot use stdio with -daemonize");
return NULL;
if (stdio_nb_clients == 0) {
old_fd0_flags = fcntl(0, F_GETFL);
tcgetattr (0, &oldtty);
......@@ -3637,6 +3637,30 @@ int main(int argc, char **argv, char **envp)
default_sdcard = 0;
if (is_daemonized()) {
/* According to documentation and historically, -nographic redirects
* serial port, parallel port and monitor to stdio, which does not work
* with -daemonize. We can redirect these to null instead, but since
* -nographic is legacy, let's just error out.
* We disallow -nographic only if all other ports are not redirected
* explicitly, to not break existing legacy setups which uses
* -nographic _and_ redirects all ports explicitly - this is valid
* usage, -nographic is just a no-op in this case.
if (display_type == DT_NOGRAPHIC
&& (default_parallel || default_serial
|| default_monitor || default_virtcon)) {
fprintf(stderr, "-nographic can not be used with -daemonize\n");
if (display_type == DT_CURSES) {
fprintf(stderr, "curses display can not be used with -daemonize\n");
if (display_type == DT_NOGRAPHIC) {
if (default_parallel)
add_device_config(DEV_PARALLEL, "null");
......@@ -3903,9 +3927,7 @@ int main(int argc, char **argv, char **envp)
#if defined(CONFIG_CURSES)
if (!is_daemonized()) {
curses_display_init(ds, full_screen);
curses_display_init(ds, full_screen);
#if defined(CONFIG_SDL)
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment