| 1 | /* |
| 2 | * Standalone VNC server connecting to QEMU via D-Bus display interface. |
| 3 | * Audio support. Only one audio stream is tracked. |
| 4 | * Mixing/resampling to be added, if needed. |
| 5 | * |
| 6 | * Copyright (C) 2026 Red Hat, Inc. |
| 7 | * |
| 8 | * SPDX-License-Identifier: GPL-2.0-or-later |
| 9 | */ |
| 10 | |
| 11 | #include "qemu/osdep.h" |
| 12 | |
| 13 | #include "qemu/audio.h" |
| 14 | #include "qemu/audio-capture.h" |
| 15 | #include "qemu/sockets.h" |
| 16 | #include "qemu/error-report.h" |
| 17 | #include "ui/dbus-display1.h" |
| 18 | #include "trace.h" |
| 19 | #include "qemu-vnc.h" |
| 20 | |
| 21 | struct CaptureVoiceOut { |
| 22 | struct audsettings as; |
| 23 | struct audio_capture_ops ops; |
| 24 | void *opaque; |
| 25 | QLIST_ENTRY(CaptureVoiceOut) entries; |
| 26 | }; |
| 27 | |
| 28 | typedef struct AudioOut { |
| 29 | guint64 id; |
| 30 | struct audsettings as; |
| 31 | } AudioOut; |
| 32 | |
| 33 | static QLIST_HEAD(, CaptureVoiceOut) capture_list = |
| 34 | QLIST_HEAD_INITIALIZER(capture_list); |
| 35 | static GDBusConnection *audio_listener_conn; |
| 36 | static AudioOut audio_out; |
| 37 | |
| 38 | static bool audsettings_eq(const struct audsettings *a, |
| 39 | const struct audsettings *b) |
| 40 | { |
| 41 | return a->freq == b->freq && |
| 42 | a->nchannels == b->nchannels && |
| 43 | a->fmt == b->fmt && |
| 44 | a->big_endian == b->big_endian; |
| 45 | } |
| 46 | |
| 47 | static gboolean |
| 48 | on_audio_out_init(QemuDBusDisplay1AudioOutListener *listener, |
| 49 | GDBusMethodInvocation *invocation, |
| 50 | guint64 id, guchar bits, gboolean is_signed, |
| 51 | gboolean is_float, guint freq, guchar nchannels, |
| 52 | guint bytes_per_frame, guint bytes_per_second, |
| 53 | gboolean be, gpointer user_data) |
| 54 | { |
| 55 | AudioFormat fmt; |
| 56 | |
| 57 | switch (bits) { |
| 58 | case 8: |
| 59 | fmt = is_signed ? AUDIO_FORMAT_S8 : AUDIO_FORMAT_U8; |
| 60 | break; |
| 61 | case 16: |
| 62 | fmt = is_signed ? AUDIO_FORMAT_S16 : AUDIO_FORMAT_U16; |
| 63 | break; |
| 64 | case 32: |
| 65 | fmt = is_float ? AUDIO_FORMAT_F32 : |
| 66 | is_signed ? AUDIO_FORMAT_S32 : AUDIO_FORMAT_U32; |
| 67 | break; |
| 68 | default: |
| 69 | g_return_val_if_reached(DBUS_METHOD_INVOCATION_HANDLED); |
| 70 | } |
| 71 | |
| 72 | struct audsettings as = { |
| 73 | .freq = freq, |
| 74 | .nchannels = nchannels, |
| 75 | .fmt = fmt, |
| 76 | .big_endian = be, |
| 77 | }; |
| 78 | audio_out = (AudioOut) { |
| 79 | .id = id, |
| 80 | .as = as, |
| 81 | }; |
| 82 | |
| 83 | trace_qemu_vnc_audio_out_init(id, freq, nchannels, bits); |
| 84 | |
| 85 | qemu_dbus_display1_audio_out_listener_complete_init( |
| 86 | listener, invocation); |
| 87 | return DBUS_METHOD_INVOCATION_HANDLED; |
| 88 | } |
| 89 | |
| 90 | static gboolean |
| 91 | on_audio_out_fini(QemuDBusDisplay1AudioOutListener *listener, |
| 92 | GDBusMethodInvocation *invocation, |
| 93 | guint64 id, gpointer user_data) |
| 94 | { |
| 95 | trace_qemu_vnc_audio_out_fini(id); |
| 96 | |
| 97 | qemu_dbus_display1_audio_out_listener_complete_fini( |
| 98 | listener, invocation); |
| 99 | return DBUS_METHOD_INVOCATION_HANDLED; |
| 100 | } |
| 101 | |
| 102 | static gboolean |
| 103 | on_audio_out_set_enabled(QemuDBusDisplay1AudioOutListener *listener, |
| 104 | GDBusMethodInvocation *invocation, |
| 105 | guint64 id, gboolean enabled, |
| 106 | gpointer user_data) |
| 107 | { |
| 108 | CaptureVoiceOut *cap; |
| 109 | |
| 110 | trace_qemu_vnc_audio_out_set_enabled(id, enabled); |
| 111 | |
| 112 | if (id == audio_out.id) { |
| 113 | QLIST_FOREACH(cap, &capture_list, entries) { |
| 114 | cap->ops.notify(cap->opaque, |
| 115 | enabled ? AUD_CNOTIFY_ENABLE |
| 116 | : AUD_CNOTIFY_DISABLE); |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | qemu_dbus_display1_audio_out_listener_complete_set_enabled( |
| 121 | listener, invocation); |
| 122 | return DBUS_METHOD_INVOCATION_HANDLED; |
| 123 | } |
| 124 | |
| 125 | static gboolean |
| 126 | on_audio_out_set_volume(QemuDBusDisplay1AudioOutListener *listener, |
| 127 | GDBusMethodInvocation *invocation, |
| 128 | guint64 id, gboolean mute, |
| 129 | GVariant *volume, gpointer user_data) |
| 130 | { |
| 131 | qemu_dbus_display1_audio_out_listener_complete_set_volume( |
| 132 | listener, invocation); |
| 133 | return DBUS_METHOD_INVOCATION_HANDLED; |
| 134 | } |
| 135 | |
| 136 | static gboolean |
| 137 | on_audio_out_write(QemuDBusDisplay1AudioOutListener *listener, |
| 138 | GDBusMethodInvocation *invocation, |
| 139 | guint64 id, GVariant *data, |
| 140 | gpointer user_data) |
| 141 | { |
| 142 | CaptureVoiceOut *cap; |
| 143 | gsize size; |
| 144 | const void *buf; |
| 145 | |
| 146 | if (id == audio_out.id) { |
| 147 | buf = g_variant_get_fixed_array(data, &size, 1); |
| 148 | |
| 149 | trace_qemu_vnc_audio_out_write(id, size); |
| 150 | |
| 151 | QLIST_FOREACH(cap, &capture_list, entries) { |
| 152 | /* we don't handle audio resampling/format conversion */ |
| 153 | if (audsettings_eq(&cap->as, &audio_out.as)) { |
| 154 | cap->ops.capture(cap->opaque, buf, size); |
| 155 | } |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | qemu_dbus_display1_audio_out_listener_complete_write( |
| 160 | listener, invocation); |
| 161 | return DBUS_METHOD_INVOCATION_HANDLED; |
| 162 | } |
| 163 | |
| 164 | CaptureVoiceOut *audio_be_add_capture( |
| 165 | AudioBackend *be, |
| 166 | const struct audsettings *as, |
| 167 | const struct audio_capture_ops *ops, |
| 168 | void *opaque) |
| 169 | { |
| 170 | CaptureVoiceOut *cap; |
| 171 | |
| 172 | if (!audio_listener_conn) { |
| 173 | return NULL; |
| 174 | } |
| 175 | |
| 176 | cap = g_new0(CaptureVoiceOut, 1); |
| 177 | cap->ops = *ops; |
| 178 | cap->opaque = opaque; |
| 179 | cap->as = *as; |
| 180 | QLIST_INSERT_HEAD(&capture_list, cap, entries); |
| 181 | |
| 182 | return cap; |
| 183 | } |
| 184 | |
| 185 | void audio_be_del_capture( |
| 186 | AudioBackend *be, |
| 187 | CaptureVoiceOut *cap, |
| 188 | void *cb_opaque) |
| 189 | { |
| 190 | if (!cap) { |
| 191 | return; |
| 192 | } |
| 193 | |
| 194 | cap->ops.destroy(cap->opaque); |
| 195 | QLIST_REMOVE(cap, entries); |
| 196 | g_free(cap); |
| 197 | } |
| 198 | |
| 199 | /* |
| 200 | * Dummy audio backend — the VNC server only needs a non-NULL pointer |
| 201 | * so that audio capture registration doesn't bail out. The pointer |
| 202 | * is never dereferenced by our code (audio_be_add_capture ignores it). |
| 203 | */ |
| 204 | static AudioBackend dummy_audio_be; |
| 205 | |
| 206 | AudioBackend *audio_get_default_audio_be(Error **errp) |
| 207 | { |
| 208 | return &dummy_audio_be; |
| 209 | } |
| 210 | |
| 211 | AudioBackend *audio_be_by_name(const char *name, Error **errp) |
| 212 | { |
| 213 | return NULL; |
| 214 | } |
| 215 | |
| 216 | static void |
| 217 | on_register_audio_listener_finished(GObject *source_object, |
| 218 | GAsyncResult *res, |
| 219 | gpointer user_data) |
| 220 | { |
| 221 | GThread *thread = user_data; |
| 222 | g_autoptr(GError) err = NULL; |
| 223 | g_autoptr(GDBusObjectSkeleton) obj = NULL; |
| 224 | GDBusObjectManagerServer *server; |
| 225 | QemuDBusDisplay1AudioOutListener *audio_skel; |
| 226 | |
| 227 | qemu_dbus_display1_audio_call_register_out_listener_finish( |
| 228 | QEMU_DBUS_DISPLAY1_AUDIO(source_object), |
| 229 | NULL, res, &err); |
| 230 | |
| 231 | if (err) { |
| 232 | error_report("RegisterOutListener failed: %s", err->message); |
| 233 | g_thread_join(thread); |
| 234 | return; |
| 235 | } |
| 236 | |
| 237 | audio_listener_conn = g_thread_join(thread); |
| 238 | if (!audio_listener_conn) { |
| 239 | return; |
| 240 | } |
| 241 | |
| 242 | server = g_dbus_object_manager_server_new(DBUS_DISPLAY1_ROOT); |
| 243 | obj = g_dbus_object_skeleton_new( |
| 244 | DBUS_DISPLAY1_ROOT "/AudioOutListener"); |
| 245 | |
| 246 | audio_skel = qemu_dbus_display1_audio_out_listener_skeleton_new(); |
| 247 | g_object_connect(audio_skel, |
| 248 | "signal::handle-init", |
| 249 | on_audio_out_init, NULL, |
| 250 | "signal::handle-fini", |
| 251 | on_audio_out_fini, NULL, |
| 252 | "signal::handle-set-enabled", |
| 253 | on_audio_out_set_enabled, NULL, |
| 254 | "signal::handle-set-volume", |
| 255 | on_audio_out_set_volume, NULL, |
| 256 | "signal::handle-write", |
| 257 | on_audio_out_write, NULL, |
| 258 | NULL); |
| 259 | g_dbus_object_skeleton_add_interface( |
| 260 | obj, G_DBUS_INTERFACE_SKELETON(audio_skel)); |
| 261 | |
| 262 | g_dbus_object_manager_server_export(server, obj); |
| 263 | g_dbus_object_manager_server_set_connection( |
| 264 | server, audio_listener_conn); |
| 265 | |
| 266 | g_dbus_connection_start_message_processing(audio_listener_conn); |
| 267 | } |
| 268 | |
| 269 | void audio_setup(GDBusObjectManager *manager) |
| 270 | { |
| 271 | g_autoptr(GError) err = NULL; |
| 272 | g_autoptr(GUnixFDList) fd_list = NULL; |
| 273 | g_autoptr(GDBusInterface) iface = NULL; |
| 274 | GThread *thread; |
| 275 | int pair[2]; |
| 276 | int idx; |
| 277 | |
| 278 | iface = g_dbus_object_manager_get_interface( |
| 279 | manager, DBUS_DISPLAY1_ROOT "/Audio", |
| 280 | "org.qemu.Display1.Audio"); |
| 281 | if (!iface) { |
| 282 | return; |
| 283 | } |
| 284 | |
| 285 | if (qemu_socketpair(AF_UNIX, SOCK_STREAM, 0, pair) < 0) { |
| 286 | error_report("audio socketpair failed: %s", strerror(errno)); |
| 287 | return; |
| 288 | } |
| 289 | |
| 290 | fd_list = g_unix_fd_list_new(); |
| 291 | idx = g_unix_fd_list_append(fd_list, pair[1], &err); |
| 292 | close(pair[1]); |
| 293 | if (idx < 0) { |
| 294 | close(pair[0]); |
| 295 | error_report("Failed to append fd: %s", err->message); |
| 296 | return; |
| 297 | } |
| 298 | |
| 299 | thread = p2p_dbus_thread_new(pair[0]); |
| 300 | |
| 301 | qemu_dbus_display1_audio_call_register_out_listener( |
| 302 | QEMU_DBUS_DISPLAY1_AUDIO(iface), |
| 303 | g_variant_new_handle(idx), |
| 304 | G_DBUS_CALL_FLAGS_NONE, -1, |
| 305 | fd_list, NULL, |
| 306 | on_register_audio_listener_finished, |
| 307 | thread); |
| 308 | } |