ui/vnc-jobs.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 #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 }