@samitouri / QOSamiQemu
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1 /*
2 * QEMU VNC display driver
3 *
4 * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
5 * Copyright (C) 2006 Fabrice Bellard
6 * Copyright (C) 2009 Red Hat, Inc
7 * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 * THE SOFTWARE.
26 */
27
28
29 #include "qemu/osdep.h"
30 #include "vnc.h"
31 #include "vnc-jobs.h"
32 #include "trace.h"
33
34 /*
35 * Locking:
36 *
37 * There are three levels of locking:
38 * - jobs queue lock: for each operation on the queue (push, pop, isEmpty?)
39 * - VncDisplay global lock: mainly used for framebuffer updates to avoid
40 * screen corruption if the framebuffer is updated
41 * while the worker is doing something.
42 * - VncState::output lock: used to make sure the output buffer is not corrupted
43 * if two threads try to write on it at the same time
44 *
45 * While the VNC worker thread is working, the VncDisplay global lock is held
46 * to avoid screen corruption (this does not block vnc_refresh() because it
47 * uses trylock()) but the output lock is not held because the thread works on
48 * its own output buffer.
49 * When the encoding job is done, the worker thread will hold the output lock
50 * and copy its output buffer in vs->output.
51 */
52
53 struct VncJobQueue {
54 QemuCond cond;
55 QemuMutex mutex;
56 QemuThread thread;
57 bool exit;
58 QTAILQ_HEAD(, VncJob) jobs;
59 };
60
61 static void vnc_lock_queue(VncJobQueue *queue)
62 {
63 qemu_mutex_lock(&queue->mutex);
64 }
65
66 static void vnc_unlock_queue(VncJobQueue *queue)
67 {
68 qemu_mutex_unlock(&queue->mutex);
69 }
70
71 VncJob *vnc_job_new(VncState *vs)
72 {
73 VncJob *job = g_new0(VncJob, 1);
74
75 assert(vs->magic == VNC_MAGIC);
76 job->vs = vs;
77 QLIST_INIT(&job->rectangles);
78 return job;
79 }
80
81 /*
82 * Do not call this after pushing the job.
83 */
84 int vnc_job_add_rect(VncJob *job, int x, int y, int w, int h)
85 {
86 VncRectEntry *entry = g_new0(VncRectEntry, 1);
87
88 trace_vnc_job_add_rect(job->vs, job, x, y, w, h);
89 assert(!QTAILQ_IN_USE(job, next));
90
91 entry->rect.x = x;
92 entry->rect.y = y;
93 entry->rect.w = w;
94 entry->rect.h = h;
95
96 QLIST_INSERT_HEAD(&job->rectangles, entry, next);
97 return 1;
98 }
99
100 static void vnc_job_free(VncJob *job)
101 {
102 VncRectEntry *entry, *tmp;
103
104 if (!job) {
105 return;
106 }
107 QLIST_FOREACH_SAFE(entry, &job->rectangles, next, tmp) {
108 /* no need for QLIST_REMOVE(entry, next) */
109 g_free(entry);
110 }
111 g_free(job);
112 }
113
114 /*
115 * Push a job onto the queue. Ownership of the job is transferred.
116 */
117 void vnc_job_push(VncJob *job)
118 {
119 VncJobQueue *queue = job->vs->vd->queue;
120
121 assert(!QTAILQ_IN_USE(job, next));
122
123 if (QLIST_EMPTY(&job->rectangles)) {
124 vnc_job_free(job);
125 } else {
126 vnc_lock_queue(queue);
127 assert(!queue->exit);
128 QTAILQ_INSERT_TAIL(&queue->jobs, job, next);
129 qemu_cond_broadcast(&queue->cond);
130 vnc_unlock_queue(queue);
131 }
132 }
133
134 static bool vnc_has_job_locked(VncState *vs)
135 {
136 VncJobQueue *queue = vs->vd->queue;
137 VncJob *job;
138
139 QTAILQ_FOREACH(job, &queue->jobs, next) {
140 if (job->vs == vs) {
141 return true;
142 }
143 }
144 return false;
145 }
146
147 void vnc_jobs_join(VncState *vs)
148 {
149 VncJobQueue *queue = vs->vd->queue;
150
151 vnc_lock_queue(queue);
152 while (vnc_has_job_locked(vs)) {
153 qemu_cond_wait(&queue->cond, &queue->mutex);
154 }
155 vnc_unlock_queue(queue);
156 vnc_jobs_consume_buffer(vs);
157 }
158
159 void vnc_jobs_consume_buffer(VncState *vs)
160 {
161 bool flush;
162
163 vnc_lock_output(vs);
164 if (!buffer_empty(&vs->jobs_buffer)) {
165 if (vs->ioc != NULL && buffer_empty(&vs->output)) {
166 g_clear_handle_id(&vs->ioc_tag, g_source_remove);
167 if (vs->disconnecting == FALSE) {
168 vs->ioc_tag = qio_channel_add_watch(
169 vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR | G_IO_OUT,
170 vnc_client_io, vs, NULL);
171 }
172 }
173 buffer_move(&vs->output, &vs->jobs_buffer);
174
175 if (vs->job_update == VNC_STATE_UPDATE_FORCE) {
176 vs->force_update_offset = vs->output.offset;
177 }
178 vs->job_update = VNC_STATE_UPDATE_NONE;
179 }
180 flush = vs->ioc != NULL && vs->abort != true;
181 vnc_unlock_output(vs);
182
183 if (flush) {
184 vnc_flush(vs);
185 }
186 }
187
188 /*
189 * Copy data for local use
190 */
191 static void vnc_async_encoding_start(VncState *orig, VncState *local)
192 {
193 buffer_init(&local->output, "vnc-worker-output");
194 local->sioc = NULL; /* Don't do any network work on this thread */
195 local->ioc = NULL; /* Don't do any network work on this thread */
196
197 local->vnc_encoding = orig->vnc_encoding;
198 local->features = orig->features;
199 local->vd = orig->vd;
200 local->write_pixels = orig->write_pixels;
201 local->client_pf = orig->client_pf;
202 local->client_endian = orig->client_endian;
203 local->hextile = orig->hextile;
204 local->client_width = orig->client_width;
205 local->client_height = orig->client_height;
206 }
207
208 static void vnc_async_encoding_end(VncState *orig, VncState *local)
209 {
210 buffer_free(&local->output);
211 orig->hextile = local->hextile;
212 }
213
214 static bool vnc_worker_clamp_rect(VncState *vs, VncJob *job, VncRect *rect)
215 {
216 trace_vnc_job_clamp_rect(vs, job, rect->x, rect->y, rect->w, rect->h);
217
218 if (rect->x >= vs->client_width) {
219 goto discard;
220 }
221 rect->w = MIN(vs->client_width - rect->x, rect->w);
222 if (rect->w == 0) {
223 goto discard;
224 }
225
226 if (rect->y >= vs->client_height) {
227 goto discard;
228 }
229 rect->h = MIN(vs->client_height - rect->y, rect->h);
230 if (rect->h == 0) {
231 goto discard;
232 }
233
234 trace_vnc_job_clamped_rect(vs, job, rect->x, rect->y, rect->w, rect->h);
235 return true;
236
237 discard:
238 trace_vnc_job_discard_rect(vs, job, rect->x, rect->y, rect->w, rect->h);
239 return false;
240 }
241
242 static int vnc_worker_thread_loop(VncJobQueue *queue)
243 {
244 VncConnection *vc;
245 VncJob *job;
246 VncRectEntry *entry, *tmp;
247 VncState vs = {};
248 int n_rectangles;
249 int saved_offset;
250
251 vnc_lock_queue(queue);
252 while (QTAILQ_EMPTY(&queue->jobs) && !queue->exit) {
253 qemu_cond_wait(&queue->cond, &queue->mutex);
254 }
255 if (queue->exit) {
256 vnc_unlock_queue(queue);
257 return 1;
258 }
259 job = QTAILQ_FIRST(&queue->jobs);
260 vnc_unlock_queue(queue);
261
262 assert(job->vs->magic == VNC_MAGIC);
263 vc = container_of(job->vs, VncConnection, vs);
264
265 vnc_lock_output(job->vs);
266 if (job->vs->ioc == NULL || job->vs->abort == true) {
267 vnc_unlock_output(job->vs);
268 goto disconnected;
269 }
270 if (buffer_empty(&job->vs->output)) {
271 /*
272 * Looks like a NOP as it obviously moves no data. But it
273 * moves the empty buffer, so we don't have to malloc a new
274 * one for vs.output
275 */
276 buffer_move_empty(&vs.output, &job->vs->output);
277 }
278 vnc_unlock_output(job->vs);
279
280 /* Make a local copy of vs and switch output buffers */
281 vnc_async_encoding_start(job->vs, &vs);
282 vs.magic = VNC_MAGIC;
283
284 /* Start sending rectangles */
285 n_rectangles = 0;
286 vnc_write_u8(&vs, VNC_MSG_SERVER_FRAMEBUFFER_UPDATE);
287 vnc_write_u8(&vs, 0);
288 saved_offset = vs.output.offset;
289 vnc_write_u16(&vs, 0);
290
291 vnc_lock_display(job->vs->vd);
292 QLIST_FOREACH_SAFE(entry, &job->rectangles, next, tmp) {
293 int n;
294
295 if (job->vs->ioc == NULL) {
296 vnc_unlock_display(job->vs->vd);
297 /* Copy persistent encoding data */
298 vnc_async_encoding_end(job->vs, &vs);
299 goto disconnected;
300 }
301
302 if (vnc_worker_clamp_rect(&vs, job, &entry->rect)) {
303 n = vnc_send_framebuffer_update(&vs, &vc->worker,
304 entry->rect.x, entry->rect.y,
305 entry->rect.w, entry->rect.h);
306
307 if (n >= 0) {
308 n_rectangles += n;
309 }
310 }
311 QLIST_REMOVE(entry, next);
312 g_free(entry);
313 }
314 trace_vnc_job_nrects(&vs, job, n_rectangles);
315 vnc_unlock_display(job->vs->vd);
316
317 /* Put n_rectangles at the beginning of the message */
318 vs.output.buffer[saved_offset] = (n_rectangles >> 8) & 0xFF;
319 vs.output.buffer[saved_offset + 1] = n_rectangles & 0xFF;
320
321 vnc_lock_output(job->vs);
322 if (job->vs->ioc != NULL) {
323 buffer_move(&job->vs->jobs_buffer, &vs.output);
324 /* Copy persistent encoding data */
325 vnc_async_encoding_end(job->vs, &vs);
326
327 qemu_bh_schedule(job->vs->bh);
328 } else {
329 /* Copy persistent encoding data */
330 vnc_async_encoding_end(job->vs, &vs);
331 }
332 vnc_unlock_output(job->vs);
333
334 disconnected:
335 vnc_lock_queue(queue);
336 QTAILQ_REMOVE(&queue->jobs, job, next);
337 vnc_unlock_queue(queue);
338 qemu_cond_broadcast(&queue->cond);
339 vnc_job_free(job);
340 vs.magic = 0;
341 return 0;
342 }
343
344 static VncJobQueue *vnc_queue_new(void)
345 {
346 VncJobQueue *queue = g_new0(VncJobQueue, 1);
347
348 qemu_cond_init(&queue->cond);
349 qemu_mutex_init(&queue->mutex);
350 QTAILQ_INIT(&queue->jobs);
351 return queue;
352 }
353
354 static void vnc_queue_free(VncJobQueue *queue)
355 {
356 qemu_cond_destroy(&queue->cond);
357 qemu_mutex_destroy(&queue->mutex);
358 g_free(queue);
359 }
360
361 static void *vnc_worker_thread(void *arg)
362 {
363 VncJobQueue *queue = arg;
364
365 while (!vnc_worker_thread_loop(queue)) ;
366
367 return NULL;
368 }
369
370 void vnc_start_worker_thread(VncDisplay *vd)
371 {
372 assert(vd->queue == NULL);
373
374 vd->queue = vnc_queue_new();
375 qemu_thread_create(&vd->queue->thread, "vnc_worker", vnc_worker_thread, vd->queue,
376 QEMU_THREAD_JOINABLE);
377 }
378
379 void vnc_stop_worker_thread(VncDisplay *vd)
380 {
381 VncJobQueue *queue = vd->queue;
382
383 if (!queue) {
384 return;
385 }
386
387 /* all VNC clients must have finished before we can stop the worker thread */
388 vnc_lock_queue(queue);
389 assert(QTAILQ_EMPTY(&queue->jobs));
390 queue->exit = true;
391 qemu_cond_broadcast(&queue->cond);
392 vnc_unlock_queue(queue);
393
394 qemu_thread_join(&queue->thread);
395 g_clear_pointer(&vd->queue, vnc_queue_free);
396 }