Hi
On Thu, Sep 27, 2018 at 11:41 AM Bishara AbuHattoum <bish...@daynix.com> wrote:
>
> Currently whenever the qemu-ga's service doesn't find the virtio-serial
> the run_agent() loops in a QGA_RETRY_INTERVAL (default 5 seconds)
> intervals and try to restart the qemu-ga which causes a synchronous loop.
> Changed to wait and listen for the serial events by registering for
> notifications a proper serial event handler that deals with events:
> DBT_DEVICEARRIVAL indicates that the device has been inserted and
> is available
> DBT_DEVICEREMOVECOMPLETE indicates that the devive has been removed
> Which allow us to determine when the channel path is available for the
> qemu-ga to restart.
>
> Signed-off-by: Bishara AbuHattoum <bish...@daynix.com>
> Signed-off-by: Sameeh Jubran <sam...@daynix.com>
looks good overall,
> ---
> qga/main.c | 101 +++++++++++++++++++++++++++++++++++++++++++-
> qga/service-win32.h | 4 ++
> 2 files changed, 104 insertions(+), 1 deletion(-)
>
> diff --git a/qga/main.c b/qga/main.c
> index 6a152eb3a7..215dcb36f1 100644
> --- a/qga/main.c
> +++ b/qga/main.c
> @@ -34,6 +34,7 @@
> #include "qemu/systemd.h"
> #include "qemu-version.h"
> #ifdef _WIN32
> +#include <dbt.h>
> #include "qga/service-win32.h"
> #include "qga/vss-win32.h"
> #endif
> @@ -101,6 +102,8 @@ struct GAState {
> bool logging_enabled;
> #ifdef _WIN32
> GAService service;
> + HANDLE channel_available_event;
> + HANDLE stop_event;
> #endif
> bool delimit_response;
> bool frozen;
> @@ -137,6 +140,7 @@ static const char *ga_freeze_whitelist[] = {
> #ifdef _WIN32
> DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
> LPVOID ctx);
> +DWORD WINAPI handle_serial_device_events(DWORD type, LPVOID data);
> VOID WINAPI service_main(DWORD argc, TCHAR *argv[]);
> #endif
> static int run_agent(GAState *s);
> @@ -729,6 +733,36 @@ static gboolean channel_init(GAState *s, const gchar
> *method, const gchar *path,
> }
>
> #ifdef _WIN32
> +DWORD WINAPI handle_serial_device_events(DWORD type, LPVOID data)
> +{
> + DWORD ret = NO_ERROR;
> + PDEV_BROADCAST_HDR broadcast_header = (PDEV_BROADCAST_HDR)data;
> +
> + if (broadcast_header->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
> + switch (type) {
> + /* Device inserted */
> + case DBT_DEVICEARRIVAL:
> + /* Start QEMU-ga's service */
> + if (!SetEvent(ga_state->channel_available_event)) {
> + ret = GetLastError();
> + }
> + break;
> + /* Device removed */
> + case DBT_DEVICEQUERYREMOVE:
> + case DBT_DEVICEREMOVEPENDING:
> + case DBT_DEVICEREMOVECOMPLETE:
> + /* Stop QEMU-ga's service */
> + if (!ResetEvent(ga_state->channel_available_event)) {
> + ret = GetLastError();
> + }
> + break;
> + default:
> + ret = ERROR_CALL_NOT_IMPLEMENTED;
> + }
> + }
> + return ret;
> +}
> +
> DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
> LPVOID ctx)
> {
> @@ -740,9 +774,13 @@ DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD
> type, LPVOID data,
> case SERVICE_CONTROL_STOP:
> case SERVICE_CONTROL_SHUTDOWN:
> quit_handler(SIGTERM);
> + SetEvent(ga_state->stop_event);
> service->status.dwCurrentState = SERVICE_STOP_PENDING;
> SetServiceStatus(service->status_handle, &service->status);
> break;
> + case SERVICE_CONTROL_DEVICEEVENT:
> + handle_serial_device_events(type, data);
> + break;
>
> default:
> ret = ERROR_CALL_NOT_IMPLEMENTED;
> @@ -769,10 +807,25 @@ VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
> service->status.dwServiceSpecificExitCode = NO_ERROR;
> service->status.dwCheckPoint = 0;
> service->status.dwWaitHint = 0;
> + DEV_BROADCAST_DEVICEINTERFACE notification_filter;
> + ZeroMemory(¬ification_filter, sizeof(notification_filter));
> + notification_filter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
> + notification_filter.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
> + notification_filter.dbcc_classguid = GUID_VIOSERIAL_PORT;
> +
> + service->device_notification_handle =
> + RegisterDeviceNotification(service->status_handle,
> + ¬ification_filter, DEVICE_NOTIFY_SERVICE_HANDLE);
> + if (!service->device_notification_handle) {
> + g_critical("Failed to register device notification handle!\n");
> + return;
> + }
> SetServiceStatus(service->status_handle, &service->status);
> + ResetEvent(ga_state->stop_event);
>
> run_agent(ga_state);
>
> + UnregisterDeviceNotification(service->device_notification_handle);
> service->status.dwCurrentState = SERVICE_STOPPED;
> SetServiceStatus(service->status_handle, &service->status);
> }
> @@ -1360,12 +1413,32 @@ static GAState *initialize_agent(GAConfig *config,
> int socket_activation)
>
> s->config = config;
> s->socket_activation = socket_activation;
> +
> +#ifdef _WIN32
> + s->channel_available_event = CreateEvent(NULL, TRUE, FALSE,
> + TEXT("ChannelAvailableEvent"));
> + if (s->channel_available_event == NULL) {
> + g_critical("CreateEvent failed");
> + return NULL;
> + }
> + s->stop_event = CreateEvent(NULL, TRUE, FALSE,
> + TEXT("StopEvent"));
> + if (s->stop_event == NULL) {
> + g_critical("CreateEvent failed");
> + return NULL;
> + }
> +#endif
> +
> ga_state = s;
> return s;
> }
>
> static void cleanup_agent(GAState *s)
> {
> +#ifdef _WIN32
> + CloseHandle(s->channel_available_event);
> + CloseHandle(s->stop_event);
> +#endif
> if (s->command_state) {
> ga_command_state_cleanup_all(s->command_state);
> ga_command_state_free(s->command_state);
> @@ -1397,6 +1470,32 @@ static int run_agent_once(GAState *s)
> return EXIT_SUCCESS;
> }
>
> +static void wait_for_channel_availability(GAState *s)
> +{
> + g_warning("waiting for channel path...");
> +#ifndef _WIN32
> + sleep(QGA_RETRY_INTERVAL);
> +#else
> + DWORD dwWaitResult;
> +
> + HANDLE lpHandles[2] = { s->channel_available_event, s->stop_event };
> +
> + dwWaitResult = WaitForMultipleObjects(2, lpHandles, false, INFINITE);
> +
> + switch (dwWaitResult) {
> + case WAIT_OBJECT_0:
> + break;
> + case (WAIT_OBJECT_0 + 1):
> + g_warning("service stopped");
> + break;
Given that both events do basically the same thing, you could use one
called generically "wakeup".
Alternatively, you could wait on the main_loop (manual iteration), and
call g_main_context_wakeup() to avoid the extra events altogether (I
think).
> + case WAIT_TIMEOUT:
> + break;
> + default:
> + g_critical("WaitForMultipleObjects failed");
> + }
> +#endif
> +}
> +
> static int run_agent(GAState *s)
> {
> int ret = EXIT_SUCCESS;
> @@ -1407,7 +1506,7 @@ static int run_agent(GAState *s)
> ret = run_agent_once(s);
> if (s->config->retry_path && !s->force_exit) {
> g_warning("agent stopped unexpectedly, restarting...");
> - sleep(QGA_RETRY_INTERVAL);
> + wait_for_channel_availability(s);
> }
> } while (s->config->retry_path && !s->force_exit);
>
> diff --git a/qga/service-win32.h b/qga/service-win32.h
> index 89e99dfede..7b16d69b57 100644
> --- a/qga/service-win32.h
> +++ b/qga/service-win32.h
> @@ -20,9 +20,13 @@
> #define QGA_SERVICE_NAME "qemu-ga"
> #define QGA_SERVICE_DESCRIPTION "Enables integration with QEMU machine
> emulator and virtualizer."
>
> +static const GUID GUID_VIOSERIAL_PORT = { 0x6fde7521, 0x1b65, 0x48ae,
> +{ 0xb6, 0x28, 0x80, 0xbe, 0x62, 0x1, 0x60, 0x26 } };
> +
> typedef struct GAService {
> SERVICE_STATUS status;
> SERVICE_STATUS_HANDLE status_handle;
> + HDEVNOTIFY device_notification_handle;
> } GAService;
>
> int ga_install_service(const char *path, const char *logfile,
> --
> 2.17.0
>
>
--
Marc-André Lureau
