/* * 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 "qemu/osdep.h" #include "vnc.h" #include "vnc-jobs.h" #include "qemu/sockets.h" #include "qemu/main-loop.h" #include "block/aio.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; 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_new0(VncJob, 1); assert(vs->magic == VNC_MAGIC); 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_new0(VncRectEntry, 1); 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; } 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) { if (vs->ioc != NULL && buffer_empty(&vs->output)) { if (vs->ioc_tag) { g_source_remove(vs->ioc_tag); } if (vs->disconnecting == FALSE) { vs->ioc_tag = qio_channel_add_watch( vs->ioc, G_IO_IN | G_IO_OUT, vnc_client_io, vs, NULL); } } buffer_move(&vs->output, &vs->jobs_buffer); if (vs->job_update == VNC_STATE_UPDATE_FORCE) { vs->force_update_offset = vs->output.offset; } vs->job_update = VNC_STATE_UPDATE_NONE; } flush = vs->ioc != NULL && 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) { buffer_init(&local->output, "vnc-worker-output"); local->sioc = NULL; /* Don't do any network work on this thread */ local->ioc = NULL; /* Don't do any network work on this thread */ local->vnc_encoding = orig->vnc_encoding; local->features = orig->features; 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; } static void vnc_async_encoding_end(VncState *orig, VncState *local) { buffer_free(&local->output); orig->tight = local->tight; orig->zlib = local->zlib; orig->hextile = local->hextile; orig->zrle = local->zrle; orig->lossy_rect = local->lossy_rect; } 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); assert(job->vs->magic == VNC_MAGIC); if (queue->exit) { return -1; } vnc_lock_output(job->vs); if (job->vs->ioc == NULL || job->vs->abort == true) { vnc_unlock_output(job->vs); goto disconnected; } if (buffer_empty(&job->vs->output)) { /* * Looks like a NOP as it obviously moves no data. But it * moves the empty buffer, so we don't have to malloc a new * one for vs.output */ buffer_move_empty(&vs.output, &job->vs->output); } vnc_unlock_output(job->vs); /* Make a local copy of vs and switch output buffers */ vnc_async_encoding_start(job->vs, &vs); vs.magic = VNC_MAGIC; /* 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->ioc == NULL) { vnc_unlock_display(job->vs->vd); /* Copy persistent encoding data */ vnc_async_encoding_end(job->vs, &vs); 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->ioc != NULL) { buffer_move(&job->vs->jobs_buffer, &vs.output); /* Copy persistent encoding data */ vnc_async_encoding_end(job->vs, &vs); qemu_bh_schedule(job->vs->bh); } else { buffer_reset(&vs.output); /* Copy persistent encoding data */ vnc_async_encoding_end(job->vs, &vs); } 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); vs.magic = 0; return 0; } static VncJobQueue *vnc_queue_init(void) { VncJobQueue *queue = g_new0(VncJobQueue, 1); 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); 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", vnc_worker_thread, q, QEMU_THREAD_DETACHED); queue = q; /* Set global queue */ }