Remove support for non-threaded VNC server

QEMU now has a fundamental requirement for pthreads, so there
is no compelling reason to retain support for the non-threaded
VNC server. Remove the --{enable,disable}-vnc-thread configure
arguments, and all CONFIG_VNC_THREAD conditionals

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 351 insertions, 0 deletions

diff --git a/ui/vnc-jobs.c b/ui/vnc-jobs.c
new file mode 100644
index 0000000000..087b84d319
--- /dev/null
+++ b/ui/vnc-jobs.c
@@ -0,0 +1,351 @@
+/*
+ * 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_socket.h"
+
+/*
+ * Locking:
+ *
+ * There is 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 hold
+ * to avoid screen corruptions (this does not block vnc_refresh() because it
+ * uses trylock()) but the output lock is not hold because the thread work 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 reetrant, so we can easilly 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->clientds = orig->clientds;
+    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;
+}
+
+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 */
+}
+
+bool vnc_worker_thread_running(void)
+{
+    return queue; /* Check 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);
+}