Patchwork [7/9] chardev: hotplug, qmp, tty

diff --git a/qapi-schema.json b/qapi-schema.json
index 8904d36..7e5c8c2 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3036,9 +3036,15 @@ 
 { 'type': 'ChardevFile', 'data': { '*in' : 'ChardevFileSource',
                                    'out' : 'ChardevFileSource' } }
 
+{ 'enum': 'ChardevPortKind', 'data': [ 'tty' ] }
+
+{ 'type': 'ChardevPort', 'data': { 'device' : 'ChardevFileSource',
+                                   'type'   : 'ChardevPortKind'} }
+
 { 'type': 'ChardevDummy', 'data': { } }
 
 { 'union': 'ChardevBackend', 'data': { 'file' : 'ChardevFile',
+                                       'port' : 'ChardevPort',
                                        'null' : 'ChardevDummy' } }
 
 { 'command': 'chardev-add', 'data': {'id'      : 'str',
diff --git a/qemu-char.c b/qemu-char.c
index 47d55ea..28e4991 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -1220,21 +1220,27 @@  static void qemu_chr_close_tty(CharDriverState *chr)
     }
 }
 
+static CharDriverState *qemu_chr_open_tty_fd(int fd)
+{
+    CharDriverState *chr;
+
+    tty_serial_init(fd, 115200, 'N', 8, 1);
+    chr = qemu_chr_open_fd(fd, fd);
+    chr->chr_ioctl = tty_serial_ioctl;
+    chr->chr_close = qemu_chr_close_tty;
+    return chr;
+}
+
 static CharDriverState *qemu_chr_open_tty(QemuOpts *opts)
 {
     const char *filename = qemu_opt_get(opts, "path");
-    CharDriverState *chr;
     int fd;
 
     TFR(fd = qemu_open(filename, O_RDWR | O_NONBLOCK));
     if (fd < 0) {
         return NULL;
     }
-    tty_serial_init(fd, 115200, 'N', 8, 1);
-    chr = qemu_chr_open_fd(fd, fd);
-    chr->chr_ioctl = tty_serial_ioctl;
-    chr->chr_close = qemu_chr_close_tty;
-    return chr;
+    return qemu_chr_open_tty_fd(fd);
 }
 #endif /* __linux__ || __sun__ */
 
@@ -2949,6 +2955,15 @@  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)
+{
+    switch (port->type) {
+    default:
+        error_setg(errp, "unknown chardev port (%d)", port->type);
+        return NULL;
+    }
+}
+
 #else /* WIN32 */
 
 static int qmp_chardev_open_file_source(ChardevFileSource *src, int flags,
@@ -2965,6 +2980,9 @@  static int qmp_chardev_open_file_source(ChardevFileSource *src, int flags,
         break;
     case CHARDEV_FILE_SOURCE_KIND_FD:
         fd = monitor_get_fd(cur_mon, src->fd, errp);
+        if (flags & O_NONBLOCK) {
+            socket_set_nonblock(fd);
+        }
         break;
     default:
         error_setg(errp, "unknown chardev file source (%d)", src->kind);
@@ -2995,6 +3013,26 @@  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)
+{
+    int flags, fd;
+
+    switch (port->type) {
+#ifdef HAVE_CHARDEV_TTY
+    case CHARDEV_PORT_KIND_TTY:
+        flags = O_RDWR | O_NONBLOCK;
+        fd = qmp_chardev_open_file_source(port->device, flags, errp);
+        if (error_is_set(errp)) {
+            return NULL;
+        }
+        return qemu_chr_open_tty_fd(fd);
+#endif
+    default:
+        error_setg(errp, "unknown chardev port (%d)", port->type);
+        return NULL;
+    }
+}
+
 #endif /* WIN32 */
 
 void qmp_chardev_add(const char *id, ChardevBackend *backend, Error **errp)
@@ -3005,6 +3043,9 @@  void qmp_chardev_add(const char *id, ChardevBackend *backend, Error **errp)
     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);
+        break;
     case CHARDEV_BACKEND_KIND_NULL:
         chr = qemu_chr_open_null(NULL);
         break;