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 995ee2bf469de6bb,
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: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/vl.c b/vl.c
index e6a8d89..f056c95 100644
--- a/vl.c
+++ b/vl.c
@@ -3637,6 +3637,30 @@
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");
+ exit(1);
+ }
+#ifdef CONFIG_CURSES
+ if (display_type == DT_CURSES) {
+ fprintf(stderr, "curses display can not be used with -daemonize\n");
+ exit(1);
+ }
+#endif
+ }
+
if (display_type == DT_NOGRAPHIC) {
if (default_parallel)
add_device_config(DEV_PARALLEL, "null");
@@ -3903,9 +3927,7 @@
break;
#if defined(CONFIG_CURSES)
case DT_CURSES:
- if (!is_daemonized()) {
- curses_display_init(ds, full_screen);
- }
+ curses_display_init(ds, full_screen);
break;
#endif
#if defined(CONFIG_SDL)
