switch chardev to QemuOpts: infrastructure, null device

start switching chardevs to QemuOpts.  This patch adds the
infrastructure and converts the null device.

The patch brings two new functions:

qemu_chr_open_opts()
	same as qemu_chr_open(), but uses QemuOpts instead of a
	option char string.

qemu_chr_parse_compat()
	accepts a traditional chardev option string, returns the
	corresponding QemuOpts instance, to handle backward
	compatibility.

The patch also adds a new -chardev switch which can be used to create
named+unconnected chardevs, like this:

	-chardev null,id=test

This uses the new qemu_chr_open_opts.  Thus with this patch alone only
the null device works.  The other devices will follow ...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/vl.c b/vl.c
index 8e5d9db3e..044676986 100644
--- a/vl.c
+++ b/vl.c
@@ -5281,6 +5281,16 @@ int main(int argc, char **argv, char **envp)
                 monitor_devices[monitor_device_index] = optarg;
                 monitor_device_index++;
                 break;
+            case QEMU_OPTION_chardev:
+                opts = qemu_opts_parse(&qemu_chardev_opts, optarg, "backend");
+                if (!opts) {
+                    fprintf(stderr, "parse error: %s\n", optarg);
+                    exit(1);
+                }
+                if (NULL == qemu_chr_open_opts(opts, NULL)) {
+                    exit(1);
+                }
+                break;
             case QEMU_OPTION_serial:
                 if (serial_device_index >= MAX_SERIAL_PORTS) {
                     fprintf(stderr, "qemu: too many serial ports\n");