xref: /openbmc/qemu/ui/vnc-jobs.c (revision a719a27c)
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 #include "qemu/sockets.h"
32 
33 /*
34  * Locking:
35  *
36  * There are three levels of locking:
37  * - jobs queue lock: for each operation on the queue (push, pop, isEmpty?)
38  * - VncDisplay global lock: mainly used for framebuffer updates to avoid
39  *                      screen corruption if the framebuffer is updated
40  *                      while the worker is doing something.
41  * - VncState::output lock: used to make sure the output buffer is not corrupted
42  *                          if two threads try to write on it at the same time
43  *
44  * While the VNC worker thread is working, the VncDisplay global lock is held
45  * to avoid screen corruption (this does not block vnc_refresh() because it
46  * uses trylock()) but the output lock is not held because the thread works on
47  * its own output buffer.
48  * When the encoding job is done, the worker thread will hold the output lock
49  * and copy its output buffer in vs->output.
50  */
51 
52 struct VncJobQueue {
53     QemuCond cond;
54     QemuMutex mutex;
55     QemuThread thread;
56     Buffer buffer;
57     bool exit;
58     QTAILQ_HEAD(, VncJob) jobs;
59 };
60 
61 typedef struct VncJobQueue VncJobQueue;
62 
63 /*
64  * We use a single global queue, but most of the functions are
65  * already reentrant, so we can easily add more than one encoding thread
66  */
67 static VncJobQueue *queue;
68 
69 static void vnc_lock_queue(VncJobQueue *queue)
70 {
71     qemu_mutex_lock(&queue->mutex);
72 }
73 
74 static void vnc_unlock_queue(VncJobQueue *queue)
75 {
76     qemu_mutex_unlock(&queue->mutex);
77 }
78 
79 VncJob *vnc_job_new(VncState *vs)
80 {
81     VncJob *job = g_malloc0(sizeof(VncJob));
82 
83     job->vs = vs;
84     vnc_lock_queue(queue);
85     QLIST_INIT(&job->rectangles);
86     vnc_unlock_queue(queue);
87     return job;
88 }
89 
90 int vnc_job_add_rect(VncJob *job, int x, int y, int w, int h)
91 {
92     VncRectEntry *entry = g_malloc0(sizeof(VncRectEntry));
93 
94     entry->rect.x = x;
95     entry->rect.y = y;
96     entry->rect.w = w;
97     entry->rect.h = h;
98 
99     vnc_lock_queue(queue);
100     QLIST_INSERT_HEAD(&job->rectangles, entry, next);
101     vnc_unlock_queue(queue);
102     return 1;
103 }
104 
105 void vnc_job_push(VncJob *job)
106 {
107     vnc_lock_queue(queue);
108     if (queue->exit || QLIST_EMPTY(&job->rectangles)) {
109         g_free(job);
110     } else {
111         QTAILQ_INSERT_TAIL(&queue->jobs, job, next);
112         qemu_cond_broadcast(&queue->cond);
113     }
114     vnc_unlock_queue(queue);
115 }
116 
117 static bool vnc_has_job_locked(VncState *vs)
118 {
119     VncJob *job;
120 
121     QTAILQ_FOREACH(job, &queue->jobs, next) {
122         if (job->vs == vs || !vs) {
123             return true;
124         }
125     }
126     return false;
127 }
128 
129 bool vnc_has_job(VncState *vs)
130 {
131     bool ret;
132 
133     vnc_lock_queue(queue);
134     ret = vnc_has_job_locked(vs);
135     vnc_unlock_queue(queue);
136     return ret;
137 }
138 
139 void vnc_jobs_clear(VncState *vs)
140 {
141     VncJob *job, *tmp;
142 
143     vnc_lock_queue(queue);
144     QTAILQ_FOREACH_SAFE(job, &queue->jobs, next, tmp) {
145         if (job->vs == vs || !vs) {
146             QTAILQ_REMOVE(&queue->jobs, job, next);
147         }
148     }
149     vnc_unlock_queue(queue);
150 }
151 
152 void vnc_jobs_join(VncState *vs)
153 {
154     vnc_lock_queue(queue);
155     while (vnc_has_job_locked(vs)) {
156         qemu_cond_wait(&queue->cond, &queue->mutex);
157     }
158     vnc_unlock_queue(queue);
159     vnc_jobs_consume_buffer(vs);
160 }
161 
162 void vnc_jobs_consume_buffer(VncState *vs)
163 {
164     bool flush;
165 
166     vnc_lock_output(vs);
167     if (vs->jobs_buffer.offset) {
168         vnc_write(vs, vs->jobs_buffer.buffer, vs->jobs_buffer.offset);
169         buffer_reset(&vs->jobs_buffer);
170     }
171     flush = vs->csock != -1 && vs->abort != true;
172     vnc_unlock_output(vs);
173 
174     if (flush) {
175       vnc_flush(vs);
176     }
177 }
178 
179 /*
180  * Copy data for local use
181  */
182 static void vnc_async_encoding_start(VncState *orig, VncState *local)
183 {
184     local->vnc_encoding = orig->vnc_encoding;
185     local->features = orig->features;
186     local->vd = orig->vd;
187     local->lossy_rect = orig->lossy_rect;
188     local->write_pixels = orig->write_pixels;
189     local->client_pf = orig->client_pf;
190     local->client_be = orig->client_be;
191     local->tight = orig->tight;
192     local->zlib = orig->zlib;
193     local->hextile = orig->hextile;
194     local->zrle = orig->zrle;
195     local->output =  queue->buffer;
196     local->csock = -1; /* Don't do any network work on this thread */
197 
198     buffer_reset(&local->output);
199 }
200 
201 static void vnc_async_encoding_end(VncState *orig, VncState *local)
202 {
203     orig->tight = local->tight;
204     orig->zlib = local->zlib;
205     orig->hextile = local->hextile;
206     orig->zrle = local->zrle;
207     orig->lossy_rect = local->lossy_rect;
208 
209     queue->buffer = local->output;
210 }
211 
212 static int vnc_worker_thread_loop(VncJobQueue *queue)
213 {
214     VncJob *job;
215     VncRectEntry *entry, *tmp;
216     VncState vs;
217     int n_rectangles;
218     int saved_offset;
219 
220     vnc_lock_queue(queue);
221     while (QTAILQ_EMPTY(&queue->jobs) && !queue->exit) {
222         qemu_cond_wait(&queue->cond, &queue->mutex);
223     }
224     /* Here job can only be NULL if queue->exit is true */
225     job = QTAILQ_FIRST(&queue->jobs);
226     vnc_unlock_queue(queue);
227 
228     if (queue->exit) {
229         return -1;
230     }
231 
232     vnc_lock_output(job->vs);
233     if (job->vs->csock == -1 || job->vs->abort == true) {
234         vnc_unlock_output(job->vs);
235         goto disconnected;
236     }
237     vnc_unlock_output(job->vs);
238 
239     /* Make a local copy of vs and switch output buffers */
240     vnc_async_encoding_start(job->vs, &vs);
241 
242     /* Start sending rectangles */
243     n_rectangles = 0;
244     vnc_write_u8(&vs, VNC_MSG_SERVER_FRAMEBUFFER_UPDATE);
245     vnc_write_u8(&vs, 0);
246     saved_offset = vs.output.offset;
247     vnc_write_u16(&vs, 0);
248 
249     vnc_lock_display(job->vs->vd);
250     QLIST_FOREACH_SAFE(entry, &job->rectangles, next, tmp) {
251         int n;
252 
253         if (job->vs->csock == -1) {
254             vnc_unlock_display(job->vs->vd);
255             /* Copy persistent encoding data */
256             vnc_async_encoding_end(job->vs, &vs);
257             goto disconnected;
258         }
259 
260         n = vnc_send_framebuffer_update(&vs, entry->rect.x, entry->rect.y,
261                                         entry->rect.w, entry->rect.h);
262 
263         if (n >= 0) {
264             n_rectangles += n;
265         }
266         g_free(entry);
267     }
268     vnc_unlock_display(job->vs->vd);
269 
270     /* Put n_rectangles at the beginning of the message */
271     vs.output.buffer[saved_offset] = (n_rectangles >> 8) & 0xFF;
272     vs.output.buffer[saved_offset + 1] = n_rectangles & 0xFF;
273 
274     vnc_lock_output(job->vs);
275     if (job->vs->csock != -1) {
276         buffer_reserve(&job->vs->jobs_buffer, vs.output.offset);
277         buffer_append(&job->vs->jobs_buffer, vs.output.buffer,
278                       vs.output.offset);
279         /* Copy persistent encoding data */
280         vnc_async_encoding_end(job->vs, &vs);
281 
282 	qemu_bh_schedule(job->vs->bh);
283     }  else {
284         /* Copy persistent encoding data */
285         vnc_async_encoding_end(job->vs, &vs);
286     }
287     vnc_unlock_output(job->vs);
288 
289 disconnected:
290     vnc_lock_queue(queue);
291     QTAILQ_REMOVE(&queue->jobs, job, next);
292     vnc_unlock_queue(queue);
293     qemu_cond_broadcast(&queue->cond);
294     g_free(job);
295     return 0;
296 }
297 
298 static VncJobQueue *vnc_queue_init(void)
299 {
300     VncJobQueue *queue = g_malloc0(sizeof(VncJobQueue));
301 
302     qemu_cond_init(&queue->cond);
303     qemu_mutex_init(&queue->mutex);
304     QTAILQ_INIT(&queue->jobs);
305     return queue;
306 }
307 
308 static void vnc_queue_clear(VncJobQueue *q)
309 {
310     qemu_cond_destroy(&queue->cond);
311     qemu_mutex_destroy(&queue->mutex);
312     buffer_free(&queue->buffer);
313     g_free(q);
314     queue = NULL; /* Unset global queue */
315 }
316 
317 static void *vnc_worker_thread(void *arg)
318 {
319     VncJobQueue *queue = arg;
320 
321     qemu_thread_get_self(&queue->thread);
322 
323     while (!vnc_worker_thread_loop(queue)) ;
324     vnc_queue_clear(queue);
325     return NULL;
326 }
327 
328 static bool vnc_worker_thread_running(void)
329 {
330     return queue; /* Check global queue */
331 }
332 
333 void vnc_start_worker_thread(void)
334 {
335     VncJobQueue *q;
336 
337     if (vnc_worker_thread_running())
338         return ;
339 
340     q = vnc_queue_init();
341     qemu_thread_create(&q->thread, "vnc_worker", vnc_worker_thread, q,
342                        QEMU_THREAD_DETACHED);
343     queue = q; /* Set global queue */
344 }
345 
346 void vnc_stop_worker_thread(void)
347 {
348     if (!vnc_worker_thread_running())
349         return ;
350 
351     /* Remove all jobs and wake up the thread */
352     vnc_lock_queue(queue);
353     queue->exit = true;
354     vnc_unlock_queue(queue);
355     vnc_jobs_clear(NULL);
356     qemu_cond_broadcast(&queue->cond);
357 }
358