[libvirt PATCH v2 39/56] util: import an event loop impl based on GMainContext
Daniel P. Berrangé
berrange at redhat.com
Tue Jan 28 13:11:20 UTC 2020
The libvirt-glib project has provided a GMainContext based
event loop impl for applications. This imports it and sets
it up for use by libvirt as the primary event loop. This
remains a private impl detail of libvirt.
IOW, applications must *NOT* assume that a call to
"virEventRegisterDefaultImpl" results in a GLib based
event loop. They should continue to use the libvirt-glib
API gvir_event_register() if they explicitly want to
guarantee a GLib event loop.
This follows the general principal that the libvirt public
API should not expose the fact that GLib is being used
internally.
Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
---
build-aux/syntax-check.mk | 2 +-
po/POTFILES.in | 1 +
src/libvirt_private.syms | 5 +
src/util/Makefile.inc.am | 2 +
src/util/vireventglib.c | 455 ++++++++++++++++++++++++++++++++++++++
src/util/vireventglib.h | 28 +++
6 files changed, 492 insertions(+), 1 deletion(-)
create mode 100644 src/util/vireventglib.c
create mode 100644 src/util/vireventglib.h
diff --git a/build-aux/syntax-check.mk b/build-aux/syntax-check.mk
index b93052b1c0..4394866963 100644
--- a/build-aux/syntax-check.mk
+++ b/build-aux/syntax-check.mk
@@ -2176,7 +2176,7 @@ exclude_file_name_regexp--sc_avoid_write = \
exclude_file_name_regexp--sc_bindtextdomain = .*
-exclude_file_name_regexp--sc_gettext_init = ^((tests|examples)/|tools/virt-login-shell.c)
+exclude_file_name_regexp--sc_gettext_init = ^((tests|examples)/|tools/virt-login-shell.c|src/util/vireventglib\.c)
exclude_file_name_regexp--sc_copyright_format = \
^build-aux/syntax-check\.mk$$
diff --git a/po/POTFILES.in b/po/POTFILES.in
index c18e21615f..4fc0d80ce7 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -238,6 +238,7 @@
@SRCDIR@/src/util/virerror.c
@SRCDIR@/src/util/virerror.h
@SRCDIR@/src/util/virevent.c
+ at SRCDIR@/src/util/vireventglib.c
@SRCDIR@/src/util/vireventpoll.c
@SRCDIR@/src/util/virfcp.c
@SRCDIR@/src/util/virfdstream.c
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 022ab29aa0..fec8abfe91 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1926,6 +1926,11 @@ virSetErrorLogPriorityFunc;
virStrerror;
+# util/vireventglib.h
+virEventGLibRegister;
+virEventGLibRunOnce;
+
+
# util/vireventpoll.h
virEventPollAddHandle;
virEventPollAddTimeout;
diff --git a/src/util/Makefile.inc.am b/src/util/Makefile.inc.am
index faa6799e7d..4179526698 100644
--- a/src/util/Makefile.inc.am
+++ b/src/util/Makefile.inc.am
@@ -63,6 +63,8 @@ UTIL_SOURCES = \
util/virerrorpriv.h \
util/virevent.c \
util/virevent.h \
+ util/vireventglib.c \
+ util/vireventglib.h \
util/vireventglibwatch.c \
util/vireventglibwatch.h \
util/vireventpoll.c \
diff --git a/src/util/vireventglib.c b/src/util/vireventglib.c
new file mode 100644
index 0000000000..be057c8e3c
--- /dev/null
+++ b/src/util/vireventglib.c
@@ -0,0 +1,455 @@
+/*
+ * vireventglib.c: GMainContext based event loop
+ *
+ * Copyright (C) 2008 Daniel P. Berrange
+ * Copyright (C) 2010-2019 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "vireventglib.h"
+#include "vireventglibwatch.h"
+#include "virerror.h"
+#include "virlog.h"
+
+#ifdef G_OS_WIN32
+# include <io.h>
+#endif
+
+#define VIR_FROM_THIS VIR_FROM_EVENT
+
+VIR_LOG_INIT("util.eventglib");
+
+struct virEventGLibHandle
+{
+ int watch;
+ int fd;
+ int events;
+ int removed;
+ guint source;
+ virEventHandleCallback cb;
+ void *opaque;
+ virFreeCallback ff;
+};
+
+struct virEventGLibTimeout
+{
+ int timer;
+ int interval;
+ int removed;
+ guint source;
+ virEventTimeoutCallback cb;
+ void *opaque;
+ virFreeCallback ff;
+};
+
+static GMutex *eventlock;
+
+static int nextwatch = 1;
+static GPtrArray *handles;
+
+static int nexttimer = 1;
+static GPtrArray *timeouts;
+
+static gboolean
+virEventGLibHandleDispatch(int fd G_GNUC_UNUSED,
+ GIOCondition condition,
+ gpointer opaque)
+{
+ struct virEventGLibHandle *data = opaque;
+ int events = 0;
+
+ if (condition & G_IO_IN)
+ events |= VIR_EVENT_HANDLE_READABLE;
+ if (condition & G_IO_OUT)
+ events |= VIR_EVENT_HANDLE_WRITABLE;
+ if (condition & G_IO_HUP)
+ events |= VIR_EVENT_HANDLE_HANGUP;
+ if (condition & G_IO_ERR)
+ events |= VIR_EVENT_HANDLE_ERROR;
+
+ VIR_DEBUG("Dispatch handler %p %d %d %d %p", data, data->watch, data->fd, events, data->opaque);
+
+ (data->cb)(data->watch, data->fd, events, data->opaque);
+
+ return TRUE;
+}
+
+
+static int
+virEventGLibHandleAdd(int fd,
+ int events,
+ virEventHandleCallback cb,
+ void *opaque,
+ virFreeCallback ff)
+{
+ struct virEventGLibHandle *data;
+ GIOCondition cond = 0;
+ int ret;
+
+ g_mutex_lock(eventlock);
+
+ data = g_new0(struct virEventGLibHandle, 1);
+
+ if (events & VIR_EVENT_HANDLE_READABLE)
+ cond |= G_IO_IN;
+ if (events & VIR_EVENT_HANDLE_WRITABLE)
+ cond |= G_IO_OUT;
+
+ data->watch = nextwatch++;
+ data->fd = fd;
+ data->events = events;
+ data->cb = cb;
+ data->opaque = opaque;
+ data->ff = ff;
+
+ VIR_DEBUG("Add handle %p %d %d %d %p", data, data->watch, data->fd, events, data->opaque);
+
+ if (events != 0) {
+ data->source = virEventGLibAddSocketWatch(
+ fd, cond, NULL, virEventGLibHandleDispatch, data, NULL);
+ }
+
+ g_ptr_array_add(handles, data);
+
+ ret = data->watch;
+
+ g_mutex_unlock(eventlock);
+
+ return ret;
+}
+
+static struct virEventGLibHandle *
+virEventGLibHandleFind(int watch)
+{
+ guint i;
+
+ for (i = 0; i < handles->len; i++) {
+ struct virEventGLibHandle *h = g_ptr_array_index(handles, i);
+
+ if (h == NULL) {
+ g_warn_if_reached();
+ continue;
+ }
+
+ if ((h->watch == watch) && !h->removed)
+ return h;
+ }
+
+ return NULL;
+}
+
+static void
+virEventGLibHandleUpdate(int watch,
+ int events)
+{
+ struct virEventGLibHandle *data;
+
+ g_mutex_lock(eventlock);
+
+ data = virEventGLibHandleFind(watch);
+ if (!data) {
+ VIR_DEBUG("Update for missing handle watch %d", watch);
+ goto cleanup;
+ }
+
+ VIR_DEBUG("Update handle %p %d %d %d", data, watch, data->fd, events);
+
+ if (events) {
+ GIOCondition cond = 0;
+ if (events == data->events)
+ goto cleanup;
+
+ if (data->source) {
+ VIR_DEBUG("Removed old watch %d", data->source);
+ g_source_remove(data->source);
+ }
+
+ cond |= G_IO_HUP;
+ if (events & VIR_EVENT_HANDLE_READABLE)
+ cond |= G_IO_IN;
+ if (events & VIR_EVENT_HANDLE_WRITABLE)
+ cond |= G_IO_OUT;
+
+ data->source = virEventGLibAddSocketWatch(
+ data->fd, cond, NULL, virEventGLibHandleDispatch, data, NULL);
+
+ data->events = events;
+ VIR_DEBUG("Added new watch %d", data->source);
+ } else {
+ if (!data->source)
+ goto cleanup;
+
+ VIR_DEBUG("Removed old watch");
+ g_source_remove(data->source);
+ data->source = 0;
+ data->events = 0;
+ }
+
+ cleanup:
+ g_mutex_unlock(eventlock);
+}
+
+static gboolean
+virEventGLibHandleRemoveIdle(gpointer data)
+{
+ struct virEventGLibHandle *h = data;
+
+ if (h->ff)
+ (h->ff)(h->opaque);
+
+ g_mutex_lock(eventlock);
+ g_ptr_array_remove_fast(handles, h);
+ g_mutex_unlock(eventlock);
+
+ return FALSE;
+}
+
+static int
+virEventGLibHandleRemove(int watch)
+{
+ struct virEventGLibHandle *data;
+ int ret = -1;
+
+ g_mutex_lock(eventlock);
+
+ data = virEventGLibHandleFind(watch);
+ if (!data) {
+ VIR_DEBUG("Remove of missing watch %d", watch);
+ goto cleanup;
+ }
+
+ VIR_DEBUG("Remove handle %p %d %d", data, watch, data->fd);
+
+ if (data->source != 0) {
+ g_source_remove(data->source);
+ data->source = 0;
+ data->events = 0;
+ }
+
+ /* since the actual watch deletion is done asynchronously, a handleUpdate call may
+ * reschedule the watch before it's fully deleted, that's why we need to mark it as
+ * 'removed' to prevent reuse
+ */
+ data->removed = TRUE;
+ g_idle_add(virEventGLibHandleRemoveIdle, data);
+
+ ret = 0;
+
+ cleanup:
+ g_mutex_unlock(eventlock);
+ return ret;
+}
+
+
+static gboolean
+virEventGLibTimeoutDispatch(void *opaque)
+{
+ struct virEventGLibTimeout *data = opaque;
+ VIR_DEBUG("Dispatch timeout data=%p cb=%p timer=%d opaque=%p", data, data->cb, data->timer, data->opaque);
+ (data->cb)(data->timer, data->opaque);
+
+ return TRUE;
+}
+
+static int
+virEventGLibTimeoutAdd(int interval,
+ virEventTimeoutCallback cb,
+ void *opaque,
+ virFreeCallback ff)
+{
+ struct virEventGLibTimeout *data;
+ int ret;
+
+ g_mutex_lock(eventlock);
+
+ data = g_new0(struct virEventGLibTimeout, 1);
+ data->timer = nexttimer++;
+ data->interval = interval;
+ data->cb = cb;
+ data->opaque = opaque;
+ data->ff = ff;
+ if (interval >= 0)
+ data->source = g_timeout_add(interval,
+ virEventGLibTimeoutDispatch,
+ data);
+
+ g_ptr_array_add(timeouts, data);
+
+ VIR_DEBUG("Add timeout data=%p interval=%d ms cb=%p opaque=%p timer=%d", data, interval, cb, opaque, data->timer);
+
+ ret = data->timer;
+
+ g_mutex_unlock(eventlock);
+
+ return ret;
+}
+
+
+static struct virEventGLibTimeout *
+virEventGLibTimeoutFind(int timer)
+{
+ guint i;
+
+ g_return_val_if_fail(timeouts != NULL, NULL);
+
+ for (i = 0; i < timeouts->len; i++) {
+ struct virEventGLibTimeout *t = g_ptr_array_index(timeouts, i);
+
+ if (t == NULL) {
+ g_warn_if_reached();
+ continue;
+ }
+
+ if ((t->timer == timer) && !t->removed)
+ return t;
+ }
+
+ return NULL;
+}
+
+
+static void
+virEventGLibTimeoutUpdate(int timer,
+ int interval)
+{
+ struct virEventGLibTimeout *data;
+
+ g_mutex_lock(eventlock);
+
+ data = virEventGLibTimeoutFind(timer);
+ if (!data) {
+ VIR_DEBUG("Update of missing timer %d", timer);
+ goto cleanup;
+ }
+
+ VIR_DEBUG("Update timeout %p %d %d", data, timer, interval);
+
+ if (interval >= 0) {
+ if (data->source)
+ g_source_remove(data->source);
+
+ data->interval = interval;
+ data->source = g_timeout_add(data->interval,
+ virEventGLibTimeoutDispatch,
+ data);
+ } else {
+ if (!data->source)
+ goto cleanup;
+
+ g_source_remove(data->source);
+ data->source = 0;
+ }
+
+ cleanup:
+ g_mutex_unlock(eventlock);
+}
+
+static gboolean
+virEventGLibTimeoutRemoveIdle(gpointer data)
+{
+ struct virEventGLibTimeout *t = data;
+
+ if (t->ff)
+ (t->ff)(t->opaque);
+
+ g_mutex_lock(eventlock);
+ g_ptr_array_remove_fast(timeouts, t);
+ g_mutex_unlock(eventlock);
+
+ return FALSE;
+}
+
+static int
+virEventGLibTimeoutRemove(int timer)
+{
+ struct virEventGLibTimeout *data;
+ int ret = -1;
+
+ g_mutex_lock(eventlock);
+
+ data = virEventGLibTimeoutFind(timer);
+ if (!data) {
+ VIR_DEBUG("Remove of missing timer %d", timer);
+ goto cleanup;
+ }
+
+ VIR_DEBUG("Remove timeout %p %d", data, timer);
+
+ if (data->source != 0) {
+ g_source_remove(data->source);
+ data->source = 0;
+ }
+
+ /* since the actual timeout deletion is done asynchronously, a timeoutUpdate call may
+ * reschedule the timeout before it's fully deleted, that's why we need to mark it as
+ * 'removed' to prevent reuse
+ */
+ data->removed = TRUE;
+ g_idle_add(virEventGLibTimeoutRemoveIdle, data);
+
+ ret = 0;
+
+ cleanup:
+ g_mutex_unlock(eventlock);
+ return ret;
+}
+
+
+static gpointer virEventGLibRegisterOnce(gpointer data G_GNUC_UNUSED)
+{
+ eventlock = g_new0(GMutex, 1);
+ timeouts = g_ptr_array_new_with_free_func(g_free);
+ handles = g_ptr_array_new_with_free_func(g_free);
+ virEventRegisterImpl(virEventGLibHandleAdd,
+ virEventGLibHandleUpdate,
+ virEventGLibHandleRemove,
+ virEventGLibTimeoutAdd,
+ virEventGLibTimeoutUpdate,
+ virEventGLibTimeoutRemove);
+ return NULL;
+}
+
+
+void virEventGLibRegister(void)
+{
+ static GOnce once = G_ONCE_INIT;
+
+ g_once(&once, virEventGLibRegisterOnce, NULL);
+}
+
+
+int virEventGLibRunOnce(void)
+{
+ GMainContext *ctx = g_main_context_default();
+
+ if (!g_main_context_acquire(ctx)) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("Another thread has acquired the main loop context"));
+ return -1;
+ }
+
+ g_main_context_iteration(ctx, TRUE);
+
+ g_main_context_release(ctx);
+
+ return 0;
+}
diff --git a/src/util/vireventglib.h b/src/util/vireventglib.h
new file mode 100644
index 0000000000..ef68abaa20
--- /dev/null
+++ b/src/util/vireventglib.h
@@ -0,0 +1,28 @@
+/*
+ * vireventglib.h: GMainContext based event loop
+ *
+ * Copyright (C) 2008 Daniel P. Berrange
+ * Copyright (C) 2010-2019 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "internal.h"
+
+void virEventGLibRegister(void);
+
+int virEventGLibRunOnce(void);
--
2.24.1
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