aboutsummaryrefslogtreecommitdiff
path: root/ui/vnc-jobs.c
blob: 0bfc0c5485b6eceadf625d4f61bb6238f4028b17 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
/*
 * QEMU VNC display driver
 *
 * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
 * Copyright (C) 2006 Fabrice Bellard
 * Copyright (C) 2009 Red Hat, Inc
 * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */


#include "vnc.h"
#include "vnc-jobs.h"
#include "qemu/sockets.h"

/*
 * Locking:
 *
 * There are three levels of locking:
 * - jobs queue lock: for each operation on the queue (push, pop, isEmpty?)
 * - VncDisplay global lock: mainly used for framebuffer updates to avoid
 *                      screen corruption if the framebuffer is updated
 *                      while the worker is doing something.
 * - VncState::output lock: used to make sure the output buffer is not corrupted
 *                          if two threads try to write on it at the same time
 *
 * While the VNC worker thread is working, the VncDisplay global lock is held
 * to avoid screen corruption (this does not block vnc_refresh() because it
 * uses trylock()) but the output lock is not held because the thread works on
 * its own output buffer.
 * When the encoding job is done, the worker thread will hold the output lock
 * and copy its output buffer in vs->output.
 */

struct VncJobQueue {
    QemuCond cond;
    QemuMutex mutex;
    QemuThread thread;
    Buffer buffer;
    bool exit;
    QTAILQ_HEAD(, VncJob) jobs;
};

typedef struct VncJobQueue VncJobQueue;

/*
 * We use a single global queue, but most of the functions are
 * already reentrant, so we can easily add more than one encoding thread
 */
static VncJobQueue *queue;

static void vnc_lock_queue(VncJobQueue *queue)
{
    qemu_mutex_lock(&queue->mutex);
}

static void vnc_unlock_queue(VncJobQueue *queue)
{
    qemu_mutex_unlock(&queue->mutex);
}

VncJob *vnc_job_new(VncState *vs)
{
    VncJob *job = g_malloc0(sizeof(VncJob));

    job->vs = vs;
    vnc_lock_queue(queue);
    QLIST_INIT(&job->rectangles);
    vnc_unlock_queue(queue);
    return job;
}

int vnc_job_add_rect(VncJob *job, int x, int y, int w, int h)
{
    VncRectEntry *entry = g_malloc0(sizeof(VncRectEntry));

    entry->rect.x = x;
    entry->rect.y = y;
    entry->rect.w = w;
    entry->rect.h = h;

    vnc_lock_queue(queue);
    QLIST_INSERT_HEAD(&job->rectangles, entry, next);
    vnc_unlock_queue(queue);
    return 1;
}

void vnc_job_push(VncJob *job)
{
    vnc_lock_queue(queue);
    if (queue->exit || QLIST_EMPTY(&job->rectangles)) {
        g_free(job);
    } else {
        QTAILQ_INSERT_TAIL(&queue->jobs, job, next);
        qemu_cond_broadcast(&queue->cond);
    }
    vnc_unlock_queue(queue);
}

static bool vnc_has_job_locked(VncState *vs)
{
    VncJob *job;

    QTAILQ_FOREACH(job, &queue->jobs, next) {
        if (job->vs == vs || !vs) {
            return true;
        }
    }
    return false;
}

bool vnc_has_job(VncState *vs)
{
    bool ret;

    vnc_lock_queue(queue);
    ret = vnc_has_job_locked(vs);
    vnc_unlock_queue(queue);
    return ret;
}

void vnc_jobs_clear(VncState *vs)
{
    VncJob *job, *tmp;

    vnc_lock_queue(queue);
    QTAILQ_FOREACH_SAFE(job, &queue->jobs, next, tmp) {
        if (job->vs == vs || !vs) {
            QTAILQ_REMOVE(&queue->jobs, job, next);
        }
    }
    vnc_unlock_queue(queue);
}

void vnc_jobs_join(VncState *vs)
{
    vnc_lock_queue(queue);
    while (vnc_has_job_locked(vs)) {
        qemu_cond_wait(&queue->cond, &queue->mutex);
    }
    vnc_unlock_queue(queue);
    vnc_jobs_consume_buffer(vs);
}

void vnc_jobs_consume_buffer(VncState *vs)
{
    bool flush;

    vnc_lock_output(vs);
    if (vs->jobs_buffer.offset) {
        vnc_write(vs, vs->jobs_buffer.buffer, vs->jobs_buffer.offset);
        buffer_reset(&vs->jobs_buffer);
    }
    flush = vs->csock != -1 && vs->abort != true;
    vnc_unlock_output(vs);

    if (flush) {
      vnc_flush(vs);
    }
}

/*
 * Copy data for local use
 */
static void vnc_async_encoding_start(VncState *orig, VncState *local)
{
    local->vnc_encoding = orig->vnc_encoding;
    local->features = orig->features;
    local->ds = orig->ds;
    local->vd = orig->vd;
    local->lossy_rect = orig->lossy_rect;
    local->write_pixels = orig->write_pixels;
    local->client_pf = orig->client_pf;
    local->client_be = orig->client_be;
    local->tight = orig->tight;
    local->zlib = orig->zlib;
    local->hextile = orig->hextile;
    local->zrle = orig->zrle;
    local->output =  queue->buffer;
    local->csock = -1; /* Don't do any network work on this thread */

    buffer_reset(&local->output);
}

static void vnc_async_encoding_end(VncState *orig, VncState *local)
{
    orig->tight = local->tight;
    orig->zlib = local->zlib;
    orig->hextile = local->hextile;
    orig->zrle = local->zrle;
    orig->lossy_rect = local->lossy_rect;

    queue->buffer = local->output;
}

static int vnc_worker_thread_loop(VncJobQueue *queue)
{
    VncJob *job;
    VncRectEntry *entry, *tmp;
    VncState vs;
    int n_rectangles;
    int saved_offset;

    vnc_lock_queue(queue);
    while (QTAILQ_EMPTY(&queue->jobs) && !queue->exit) {
        qemu_cond_wait(&queue->cond, &queue->mutex);
    }
    /* Here job can only be NULL if queue->exit is true */
    job = QTAILQ_FIRST(&queue->jobs);
    vnc_unlock_queue(queue);

    if (queue->exit) {
        return -1;
    }

    vnc_lock_output(job->vs);
    if (job->vs->csock == -1 || job->vs->abort == true) {
        vnc_unlock_output(job->vs);
        goto disconnected;
    }
    vnc_unlock_output(job->vs);

    /* Make a local copy of vs and switch output buffers */
    vnc_async_encoding_start(job->vs, &vs);

    /* Start sending rectangles */
    n_rectangles = 0;
    vnc_write_u8(&vs, VNC_MSG_SERVER_FRAMEBUFFER_UPDATE);
    vnc_write_u8(&vs, 0);
    saved_offset = vs.output.offset;
    vnc_write_u16(&vs, 0);

    vnc_lock_display(job->vs->vd);
    QLIST_FOREACH_SAFE(entry, &job->rectangles, next, tmp) {
        int n;

        if (job->vs->csock == -1) {
            vnc_unlock_display(job->vs->vd);
            goto disconnected;
        }

        n = vnc_send_framebuffer_update(&vs, entry->rect.x, entry->rect.y,
                                        entry->rect.w, entry->rect.h);

        if (n >= 0) {
            n_rectangles += n;
        }
        g_free(entry);
    }
    vnc_unlock_display(job->vs->vd);

    /* Put n_rectangles at the beginning of the message */
    vs.output.buffer[saved_offset] = (n_rectangles >> 8) & 0xFF;
    vs.output.buffer[saved_offset + 1] = n_rectangles & 0xFF;

    vnc_lock_output(job->vs);
    if (job->vs->csock != -1) {
        buffer_reserve(&job->vs->jobs_buffer, vs.output.offset);
        buffer_append(&job->vs->jobs_buffer, vs.output.buffer,
                      vs.output.offset);
        /* Copy persistent encoding data */
        vnc_async_encoding_end(job->vs, &vs);

	qemu_bh_schedule(job->vs->bh);
    }
    vnc_unlock_output(job->vs);

disconnected:
    vnc_lock_queue(queue);
    QTAILQ_REMOVE(&queue->jobs, job, next);
    vnc_unlock_queue(queue);
    qemu_cond_broadcast(&queue->cond);
    g_free(job);
    return 0;
}

static VncJobQueue *vnc_queue_init(void)
{
    VncJobQueue *queue = g_malloc0(sizeof(VncJobQueue));

    qemu_cond_init(&queue->cond);
    qemu_mutex_init(&queue->mutex);
    QTAILQ_INIT(&queue->jobs);
    return queue;
}

static void vnc_queue_clear(VncJobQueue *q)
{
    qemu_cond_destroy(&queue->cond);
    qemu_mutex_destroy(&queue->mutex);
    buffer_free(&queue->buffer);
    g_free(q);
    queue = NULL; /* Unset global queue */
}

static void *vnc_worker_thread(void *arg)
{
    VncJobQueue *queue = arg;

    qemu_thread_get_self(&queue->thread);

    while (!vnc_worker_thread_loop(queue)) ;
    vnc_queue_clear(queue);
    return NULL;
}

static bool vnc_worker_thread_running(void)
{
    return queue; /* Check global queue */
}

void vnc_start_worker_thread(void)
{
    VncJobQueue *q;

    if (vnc_worker_thread_running())
        return ;

    q = vnc_queue_init();
    qemu_thread_create(&q->thread, vnc_worker_thread, q, QEMU_THREAD_DETACHED);
    queue = q; /* Set global queue */
}

void vnc_stop_worker_thread(void)
{
    if (!vnc_worker_thread_running())
        return ;

    /* Remove all jobs and wake up the thread */
    vnc_lock_queue(queue);
    queue->exit = true;
    vnc_unlock_queue(queue);
    vnc_jobs_clear(NULL);
    qemu_cond_broadcast(&queue->cond);
}