keep the PID file locked for the lifetime of the process
[qemu.git] / ui / vnc-jobs-async.c
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 "vnc.h"
30 #include "vnc-jobs.h"
31
32 /*
33 * Locking:
34 *
35 * There is three levels of locking:
36 * - jobs queue lock: for each operation on the queue (push, pop, isEmpty?)
37 * - VncDisplay global lock: mainly used for framebuffer updates to avoid
38 * screen corruption if the framebuffer is updated
39 * while the worker is doing something.
40 * - VncState::output lock: used to make sure the output buffer is not corrupted
41 * if two threads try to write on it at the same time
42 *
43 * While the VNC worker thread is working, the VncDisplay global lock is hold
44 * to avoid screen corruptions (this does not block vnc_refresh() because it
45 * uses trylock()) but the output lock is not hold because the thread work on
46 * its own output buffer.
47 * When the encoding job is done, the worker thread will hold the output lock
48 * and copy its output buffer in vs->output.
49 */
50
51 struct VncJobQueue {
52 QemuCond cond;
53 QemuMutex mutex;
54 QemuThread thread;
55 Buffer buffer;
56 bool exit;
57 QTAILQ_HEAD(, VncJob) jobs;
58 };
59
60 typedef struct VncJobQueue VncJobQueue;
61
62 /*
63 * We use a single global queue, but most of the functions are
64 * already reetrant, so we can easilly add more than one encoding thread
65 */
66 static VncJobQueue *queue;
67
68 static void vnc_lock_queue(VncJobQueue *queue)
69 {
70 qemu_mutex_lock(&queue->mutex);
71 }
72
73 static void vnc_unlock_queue(VncJobQueue *queue)
74 {
75 qemu_mutex_unlock(&queue->mutex);
76 }
77
78 VncJob *vnc_job_new(VncState *vs)
79 {
80 VncJob *job = g_malloc0(sizeof(VncJob));
81
82 job->vs = vs;
83 vnc_lock_queue(queue);
84 QLIST_INIT(&job->rectangles);
85 vnc_unlock_queue(queue);
86 return job;
87 }
88
89 int vnc_job_add_rect(VncJob *job, int x, int y, int w, int h)
90 {
91 VncRectEntry *entry = g_malloc0(sizeof(VncRectEntry));
92
93 entry->rect.x = x;
94 entry->rect.y = y;
95 entry->rect.w = w;
96 entry->rect.h = h;
97
98 vnc_lock_queue(queue);
99 QLIST_INSERT_HEAD(&job->rectangles, entry, next);
100 vnc_unlock_queue(queue);
101 return 1;
102 }
103
104 void vnc_job_push(VncJob *job)
105 {
106 vnc_lock_queue(queue);
107 if (queue->exit || QLIST_EMPTY(&job->rectangles)) {
108 g_free(job);
109 } else {
110 QTAILQ_INSERT_TAIL(&queue->jobs, job, next);
111 qemu_cond_broadcast(&queue->cond);
112 }
113 vnc_unlock_queue(queue);
114 }
115
116 static bool vnc_has_job_locked(VncState *vs)
117 {
118 VncJob *job;
119
120 QTAILQ_FOREACH(job, &queue->jobs, next) {
121 if (job->vs == vs || !vs) {
122 return true;
123 }
124 }
125 return false;
126 }
127
128 bool vnc_has_job(VncState *vs)
129 {
130 bool ret;
131
132 vnc_lock_queue(queue);
133 ret = vnc_has_job_locked(vs);
134 vnc_unlock_queue(queue);
135 return ret;
136 }
137
138 void vnc_jobs_clear(VncState *vs)
139 {
140 VncJob *job, *tmp;
141
142 vnc_lock_queue(queue);
143 QTAILQ_FOREACH_SAFE(job, &queue->jobs, next, tmp) {
144 if (job->vs == vs || !vs) {
145 QTAILQ_REMOVE(&queue->jobs, job, next);
146 }
147 }
148 vnc_unlock_queue(queue);
149 }
150
151 void vnc_jobs_join(VncState *vs)
152 {
153 vnc_lock_queue(queue);
154 while (vnc_has_job_locked(vs)) {
155 qemu_cond_wait(&queue->cond, &queue->mutex);
156 }
157 vnc_unlock_queue(queue);
158 }
159
160 /*
161 * Copy data for local use
162 */
163 static void vnc_async_encoding_start(VncState *orig, VncState *local)
164 {
165 local->vnc_encoding = orig->vnc_encoding;
166 local->features = orig->features;
167 local->ds = orig->ds;
168 local->vd = orig->vd;
169 local->lossy_rect = orig->lossy_rect;
170 local->write_pixels = orig->write_pixels;
171 local->clientds = orig->clientds;
172 local->tight = orig->tight;
173 local->zlib = orig->zlib;
174 local->hextile = orig->hextile;
175 local->zrle = orig->zrle;
176 local->output = queue->buffer;
177 local->csock = -1; /* Don't do any network work on this thread */
178
179 buffer_reset(&local->output);
180 }
181
182 static void vnc_async_encoding_end(VncState *orig, VncState *local)
183 {
184 orig->tight = local->tight;
185 orig->zlib = local->zlib;
186 orig->hextile = local->hextile;
187 orig->zrle = local->zrle;
188 orig->lossy_rect = local->lossy_rect;
189
190 queue->buffer = local->output;
191 }
192
193 static int vnc_worker_thread_loop(VncJobQueue *queue)
194 {
195 VncJob *job;
196 VncRectEntry *entry, *tmp;
197 VncState vs;
198 int n_rectangles;
199 int saved_offset;
200 bool flush;
201
202 vnc_lock_queue(queue);
203 while (QTAILQ_EMPTY(&queue->jobs) && !queue->exit) {
204 qemu_cond_wait(&queue->cond, &queue->mutex);
205 }
206 /* Here job can only be NULL if queue->exit is true */
207 job = QTAILQ_FIRST(&queue->jobs);
208 vnc_unlock_queue(queue);
209
210 if (queue->exit) {
211 return -1;
212 }
213
214 vnc_lock_output(job->vs);
215 if (job->vs->csock == -1 || job->vs->abort == true) {
216 goto disconnected;
217 }
218 vnc_unlock_output(job->vs);
219
220 /* Make a local copy of vs and switch output buffers */
221 vnc_async_encoding_start(job->vs, &vs);
222
223 /* Start sending rectangles */
224 n_rectangles = 0;
225 vnc_write_u8(&vs, VNC_MSG_SERVER_FRAMEBUFFER_UPDATE);
226 vnc_write_u8(&vs, 0);
227 saved_offset = vs.output.offset;
228 vnc_write_u16(&vs, 0);
229
230 vnc_lock_display(job->vs->vd);
231 QLIST_FOREACH_SAFE(entry, &job->rectangles, next, tmp) {
232 int n;
233
234 if (job->vs->csock == -1) {
235 vnc_unlock_display(job->vs->vd);
236 /* output mutex must be locked before going to
237 * disconnected:
238 */
239 vnc_lock_output(job->vs);
240 goto disconnected;
241 }
242
243 n = vnc_send_framebuffer_update(&vs, entry->rect.x, entry->rect.y,
244 entry->rect.w, entry->rect.h);
245
246 if (n >= 0) {
247 n_rectangles += n;
248 }
249 g_free(entry);
250 }
251 vnc_unlock_display(job->vs->vd);
252
253 /* Put n_rectangles at the beginning of the message */
254 vs.output.buffer[saved_offset] = (n_rectangles >> 8) & 0xFF;
255 vs.output.buffer[saved_offset + 1] = n_rectangles & 0xFF;
256
257 /* Switch back buffers */
258 vnc_lock_output(job->vs);
259 if (job->vs->csock == -1) {
260 goto disconnected;
261 }
262
263 vnc_write(job->vs, vs.output.buffer, vs.output.offset);
264
265 disconnected:
266 /* Copy persistent encoding data */
267 vnc_async_encoding_end(job->vs, &vs);
268 flush = (job->vs->csock != -1 && job->vs->abort != true);
269 vnc_unlock_output(job->vs);
270
271 if (flush) {
272 vnc_flush(job->vs);
273 }
274
275 vnc_lock_queue(queue);
276 QTAILQ_REMOVE(&queue->jobs, job, next);
277 vnc_unlock_queue(queue);
278 qemu_cond_broadcast(&queue->cond);
279 g_free(job);
280 return 0;
281 }
282
283 static VncJobQueue *vnc_queue_init(void)
284 {
285 VncJobQueue *queue = g_malloc0(sizeof(VncJobQueue));
286
287 qemu_cond_init(&queue->cond);
288 qemu_mutex_init(&queue->mutex);
289 QTAILQ_INIT(&queue->jobs);
290 return queue;
291 }
292
293 static void vnc_queue_clear(VncJobQueue *q)
294 {
295 qemu_cond_destroy(&queue->cond);
296 qemu_mutex_destroy(&queue->mutex);
297 buffer_free(&queue->buffer);
298 g_free(q);
299 queue = NULL; /* Unset global queue */
300 }
301
302 static void *vnc_worker_thread(void *arg)
303 {
304 VncJobQueue *queue = arg;
305
306 qemu_thread_get_self(&queue->thread);
307
308 while (!vnc_worker_thread_loop(queue)) ;
309 vnc_queue_clear(queue);
310 return NULL;
311 }
312
313 void vnc_start_worker_thread(void)
314 {
315 VncJobQueue *q;
316
317 if (vnc_worker_thread_running())
318 return ;
319
320 q = vnc_queue_init();
321 qemu_thread_create(&q->thread, vnc_worker_thread, q, QEMU_THREAD_DETACHED);
322 queue = q; /* Set global queue */
323 }
324
325 bool vnc_worker_thread_running(void)
326 {
327 return queue; /* Check global queue */
328 }
329
330 void vnc_stop_worker_thread(void)
331 {
332 if (!vnc_worker_thread_running())
333 return ;
334
335 /* Remove all jobs and wake up the thread */
336 vnc_lock_queue(queue);
337 queue->exit = true;
338 vnc_unlock_queue(queue);
339 vnc_jobs_clear(NULL);
340 qemu_cond_broadcast(&queue->cond);
341 }