[Qemu-devel] [PATCH v2] stop using stdio for monitor/serial/etc with -daemonize

[Michael Tokarev]

Current code binds monitor and serial port to the guest console
unless -nographic is specified, which is okay.  But when there's
no guest console (-nographic), the code tries to use stdio for
the same default devices.  But it does not check for -daemonize
at the same time -- because when -daemonize is given, there's no
point at using stdin since it will be closed down the line.
However, when serial port is attached to stdin, tty control
modes are changed (switching tty to raw mode), and qemu will
switch to background, leaving the tty in bad state.

Take -daemonize into account too, when assigning default devices,
and for -nographic -daemonize case, assign them to "null" instead.

This is https://bugs.launchpad.net/qemu/+bug/1024275
or http://bugs.debian.org/549195 .

While at it, reformat this code a bit to be less of a maze of
ifs and use a variable to hold common target of devices.

This patch depends on another patch, 995ee2bf469de6,
"curses: don't initialize curses when qemu is daemonized",
by Hitoshi Mitake, which creates is_daemonized() routine.

Signed-off-by: Michael Tokarev <address@hidden>
---
 vl.c |   45 +++++++++++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/vl.c b/vl.c
index 48049ef..a210ff9 100644
--- a/vl.c
+++ b/vl.c
@@ -3392,30 +3392,39 @@ int main(int argc, char **argv, char **envp)
         default_sdcard = 0;
     }
 
-    if (display_type == DT_NOGRAPHIC) {
-        if (default_parallel)
-            add_device_config(DEV_PARALLEL, "null");
+    /* Create default monitor, serial, parallel and virtcon devices. */
+    /* reuse optarg variable */
+    optarg = NULL;
+    if (display_type != DT_NOGRAPHIC) {
+        /* regular case, all devices directed to the guest console */
+        optarg = "vc:80Cx24C";
+    } else if (is_daemonized()) {
+        /* nographic and daemonize, everything => null */
+        optarg = "null";
+    } else {
+        /* nographic and no daemonize */
+        /* can't have both serial and virtcon on stdio */
         if (default_serial && default_monitor) {
             add_device_config(DEV_SERIAL, "mon:stdio");
         } else if (default_virtcon && default_monitor) {
             add_device_config(DEV_VIRTCON, "mon:stdio");
         } else {
-            if (default_serial)
-                add_device_config(DEV_SERIAL, "stdio");
-            if (default_virtcon)
-                add_device_config(DEV_VIRTCON, "stdio");
-            if (default_monitor)
-                monitor_parse("stdio", "readline");
+            optarg = "stdio";
         }
-    } else {
-        if (default_serial)
-            add_device_config(DEV_SERIAL, "vc:80Cx24C");
-        if (default_parallel)
-            add_device_config(DEV_PARALLEL, "vc:80Cx24C");
-        if (default_monitor)
-            monitor_parse("vc:80Cx24C", "readline");
-        if (default_virtcon)
-            add_device_config(DEV_VIRTCON, "vc:80Cx24C");
+    }
+    if (optarg && default_serial) {
+        add_device_config(DEV_SERIAL, optarg);
+    }
+    if (default_parallel) {
+        /* parallel port is connected console or to null */
+        add_device_config(DEV_PARALLEL,
+                          display_type == DT_NOGRAPHIC ? "null" : optarg);
+    }
+    if (optarg && default_monitor) {
+        monitor_parse(optarg, "readline");
+    }
+    if (optarg && default_virtcon) {
+        add_device_config(DEV_VIRTCON, optarg);
     }
 
     socket_init();
-- 
1.7.10.4