qapi: Flatten away ChardevPort

Simplifies the schema and the code.

QMP command

    { "execute" : "chardev-add",
      "arguments" : { "id" : "ser0",
                      "backend" : { "type" : "port",
                                    "data" : { "type": "serial",
                                               "device":"/dev/ttyS0"} } } }

becomes

    { "execute" : "chardev-add",
      "arguments" : { "id" : "ser0",
                      "backend" : { "type" : "serial",
                                    "data" : { "device":"/dev/ttyS0"} } } }

Bonus: nicer error messages.  "unknown chardev port (1)" becomes
"character device backend type 'parallel' not supported".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1360767256-610-3-git-send-email-armbru@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

2 files changed, 45 insertions, 42 deletions

diff --git a/qapi-schema.json b/qapi-schema.json
index bd289aeb51..7275b5dd6a 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3095,7 +3095,7 @@
                                    'out' : 'str' } }
 
 ##
-# @ChardevPort:
+# @ChardevHostdev:
 #
 # Configuration info for device chardevs.
 #
@@ -3105,11 +3105,7 @@
 #
 # Since: 1.4
 ##
-{ 'enum': 'ChardevPortKind', 'data': [ 'serial',
-                                       'parallel' ] }
-
-{ 'type': 'ChardevPort', 'data': { 'device' : 'str',
-                                   'type'   : 'ChardevPortKind'} }
+{ 'type': 'ChardevHostdev', 'data': { 'device' : 'str' } }
 
 ##
 # @ChardevSocket:
@@ -3142,7 +3138,8 @@
 { 'type': 'ChardevDummy', 'data': { } }
 
 { 'union': 'ChardevBackend', 'data': { 'file'   : 'ChardevFile',
-                                       'port'   : 'ChardevPort',
+                                       'serial' : 'ChardevHostdev',
+                                       'parallel': 'ChardevHostdev',
                                        'socket' : 'ChardevSocket',
                                        'pty'    : 'ChardevDummy',
                                        'null'   : 'ChardevDummy' } }
diff --git a/qemu-char.c b/qemu-char.c
index 574d3d292f..e4b0f5304f 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3269,15 +3269,17 @@ static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
     return qemu_chr_open_win_file(out);
 }
 
-static CharDriverState *qmp_chardev_open_port(ChardevPort *port, Error **errp)
+static CharDriverState *qmp_chardev_open_serial(ChardevHostdev *serial,
+                                                Error **errp)
 {
-    switch (port->type) {
-    case CHARDEV_PORT_KIND_SERIAL:
-        return qemu_chr_open_win_path(port->device);
-    default:
-        error_setg(errp, "unknown chardev port (%d)", port->type);
-        return NULL;
-    }
+    return qemu_chr_open_win_path(serial->device);
+}
+
+static CharDriverState *qmp_chardev_open_parallel(ChardevHostdev *parallel,
+                                                  Error **errp)
+{
+    error_setg(errp, "character device backend type 'parallel' not supported");
+    return NULL;
 }
 
 #else /* WIN32 */
@@ -3316,38 +3318,39 @@ static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
     return qemu_chr_open_fd(in, out);
 }
 
-static CharDriverState *qmp_chardev_open_port(ChardevPort *port, Error **errp)
+static CharDriverState *qmp_chardev_open_serial(ChardevHostdev *serial,
+                                                Error **errp)
 {
-    switch (port->type) {
 #ifdef HAVE_CHARDEV_TTY
-    case CHARDEV_PORT_KIND_SERIAL:
-    {
-        int flags, fd;
-        flags = O_RDWR;
-        fd = qmp_chardev_open_file_source(port->device, flags, errp);
-        if (error_is_set(errp)) {
-            return NULL;
-        }
-        socket_set_nonblock(fd);
-        return qemu_chr_open_tty_fd(fd);
+    int fd;
+
+    fd = qmp_chardev_open_file_source(serial->device, O_RDWR, errp);
+    if (error_is_set(errp)) {
+        return NULL;
     }
+    socket_set_nonblock(fd);
+    return qemu_chr_open_tty_fd(fd);
+#else
+    error_setg(errp, "character device backend type 'serial' not supported");
+    return NULL;
 #endif
+}
+
+static CharDriverState *qmp_chardev_open_parallel(ChardevHostdev *parallel,
+                                                  Error **errp)
+{
 #ifdef HAVE_CHARDEV_PARPORT
-    case CHARDEV_PORT_KIND_PARALLEL:
-    {
-        int flags, fd;
-        flags = O_RDWR;
-        fd = qmp_chardev_open_file_source(port->device, flags, errp);
-        if (error_is_set(errp)) {
-            return NULL;
-        }
-        return qemu_chr_open_pp_fd(fd);
-    }
-#endif
-    default:
-        error_setg(errp, "unknown chardev port (%d)", port->type);
+    int fd;
+
+    fd = qmp_chardev_open_file_source(parallel->device, O_RDWR, errp);
+    if (error_is_set(errp)) {
         return NULL;
     }
+    return qemu_chr_open_pp_fd(fd);
+#else
+    error_setg(errp, "character device backend type 'parallel' not supported");
+    return NULL;
+#endif
 }
 
 #endif /* WIN32 */
@@ -3391,8 +3394,11 @@ ChardevReturn *qmp_chardev_add(const char *id, ChardevBackend *backend,
     case CHARDEV_BACKEND_KIND_FILE:
         chr = qmp_chardev_open_file(backend->file, errp);
         break;
-    case CHARDEV_BACKEND_KIND_PORT:
-        chr = qmp_chardev_open_port(backend->port, errp);
+    case CHARDEV_BACKEND_KIND_SERIAL:
+        chr = qmp_chardev_open_serial(backend->serial, errp);
+        break;
+    case CHARDEV_BACKEND_KIND_PARALLEL:
+        chr = qmp_chardev_open_parallel(backend->parallel, errp);
         break;
     case CHARDEV_BACKEND_KIND_SOCKET:
         chr = qmp_chardev_open_socket(backend->socket, errp);