vdservice: stop service on virtio failure

read & write are async, and their completion is handled by handle_event(),
which returns status used by service execute loop.
previously an error in GetOverlappedResult caused vdservice hang.

rhbz#839564

6 files changed, 27 insertions, 23 deletions

diff --git a/vdservice/pci_vdi_port.cpp b/vdservice/pci_vdi_port.cpp
index 4deace1..7466fbc 100644
--- a/vdservice/pci_vdi_port.cpp
+++ b/vdservice/pci_vdi_port.cpp
@@ -124,8 +124,9 @@ int PCIVDIPort::read()
     return n;

 }

 

-void PCIVDIPort::handle_event(int event)

+bool PCIVDIPort::handle_event(int event)

 {

     // do nothing - the event merely serves to wake us up, then we call read/write

     // at VDService::execute start of while(_running) loop.

+    return true;

 }

diff --git a/vdservice/pci_vdi_port.h b/vdservice/pci_vdi_port.h
index caa990f..fcc76dc 100644
--- a/vdservice/pci_vdi_port.h
+++ b/vdservice/pci_vdi_port.h
@@ -41,7 +41,7 @@ public:
     virtual int read();

     virtual unsigned get_num_events() { return PCI_VDI_PORT_EVENT_COUNT; }

     virtual void fill_events(HANDLE* handles);

-    virtual void handle_event(int event);

+    virtual bool handle_event(int event);

 

 private:

     HANDLE _handle;

diff --git a/vdservice/vdi_port.h b/vdservice/vdi_port.h
index 50c4d29..a0fb20e 100644
--- a/vdservice/vdi_port.h
+++ b/vdservice/vdi_port.h
@@ -61,7 +61,7 @@ public:
     virtual bool init() = 0;

     virtual unsigned get_num_events() = 0;

     virtual void fill_events(HANDLE* handles) = 0;

-    virtual void handle_event(int event) = 0;

+    virtual bool handle_event(int event) = 0;

     virtual int write() = 0;

     virtual int read() = 0;

 

diff --git a/vdservice/vdservice.cpp b/vdservice/vdservice.cpp
index b48cbeb..2b925fd 100644
--- a/vdservice/vdservice.cpp
+++ b/vdservice/vdservice.cpp
@@ -130,7 +130,6 @@ private:
     bool _running;
     VDLog* _log;
     unsigned _events_count;
-    unsigned _events_vdi_port_base;
 };
 
 VDService* VDService::_singleton = NULL;
@@ -185,7 +184,6 @@ VDService::VDService()
     , _running (false)
     , _log (NULL)
     , _events_count(0)
-    , _events_vdi_port_base(0)
 {
     ZeroMemory(&_agent_proc_info, sizeof(_agent_proc_info));
     ZeroMemory(&_pipe_state, sizeof(_pipe_state));
@@ -536,13 +534,12 @@ bool VDService::execute()
     vd_printf("created %s", _vdi_port->name());
     _events_count = VD_STATIC_EVENTS_COUNT + _vdi_port->get_num_events() + 1 /*for agent*/;
     _events = new HANDLE[_events_count];
-    _events_vdi_port_base = VD_STATIC_EVENTS_COUNT;
     ZeroMemory(_events, _events_count);
     vd_printf("Connected to server");
     _events[VD_EVENT_PIPE_READ] = _pipe_state.read.overlap.hEvent;
     _events[VD_EVENT_PIPE_WRITE] = _pipe_state.write.overlap.hEvent;
     _events[VD_EVENT_CONTROL] = _control_event;
-    _vdi_port->fill_events(&_events[_events_vdi_port_base]);
+    _vdi_port->fill_events(&_events[VD_STATIC_EVENTS_COUNT]);
     _chunk_size = _chunk_port = 0;
     read_pipe();
     while (_running) {
@@ -602,12 +599,12 @@ bool VDService::execute()
                         }
                     }
                 } else {
-                    if (wait_ret >= WAIT_OBJECT_0 + _events_vdi_port_base &&
-                        wait_ret < WAIT_OBJECT_0 +
-                                   _events_vdi_port_base + _vdi_port->get_num_events()) {
-                        _vdi_port->handle_event(wait_ret - VD_STATIC_EVENTS_COUNT - WAIT_OBJECT_0);
+                    int vdi_event = wait_ret - VD_STATIC_EVENTS_COUNT - WAIT_OBJECT_0;
+                    if (vdi_event >= 0 && vdi_event < _vdi_port->get_num_events()) {
+                        _running = _vdi_port->handle_event(vdi_event);
                     } else {
                         vd_printf("WaitForMultipleObjects failed %lu", GetLastError());
+                        _running = false;
                     }
                 }
             }
diff --git a/vdservice/virtio_vdi_port.cpp b/vdservice/virtio_vdi_port.cpp
index 92eb129..be5568a 100644
--- a/vdservice/virtio_vdi_port.cpp
+++ b/vdservice/virtio_vdi_port.cpp
@@ -51,17 +51,21 @@ void VirtioVDIPort::fill_events(HANDLE* handles) {
     handles[VIRTIO_VDI_PORT_EVENT_READ] = _read.overlap.hEvent;

 }

 

-void VirtioVDIPort::handle_event(int event) {

+bool VirtioVDIPort::handle_event(int event) {

+    bool ret;

+

     switch (event) {

         case VIRTIO_VDI_PORT_EVENT_WRITE:

-            write_completion();

+            ret = write_completion();

             break;

         case VIRTIO_VDI_PORT_EVENT_READ:

-            read_completion();

+            ret = read_completion();

             break;

         default:

             vd_printf("ERROR: unexpected event %d", event);

+            ret = false;

     }

+    return ret;

 }

 

 bool VirtioVDIPort::init()

@@ -113,20 +117,21 @@ int VirtioVDIPort::write()
     return ret;

 }

 

-void VirtioVDIPort::write_completion()

+bool VirtioVDIPort::write_completion()

 {

     DWORD bytes;

 

     if (!_write.pending) {

-        return;

+        return true;

     }

     if (!GetOverlappedResult(_handle, &_write.overlap, &bytes, FALSE)) {

         vd_printf("GetOverlappedResult failed: %lu", GetLastError());

-        return;

+        return false;

     }

     _write.start = _write.ring + (_write.start - _write.ring + bytes) % BUF_SIZE;

     _write.bytes = bytes;

     _write.pending = false;

+    return true;

 }

 

 int VirtioVDIPort::read()

@@ -160,7 +165,7 @@ int VirtioVDIPort::read()
     return ret;

 }

 

-void VirtioVDIPort::read_completion()

+bool VirtioVDIPort::read_completion()

 {

     DWORD bytes;

 

@@ -169,13 +174,14 @@ void VirtioVDIPort::read_completion()
 

         if (err == ERROR_OPERATION_ABORTED || err == ERROR_NO_SYSTEM_RESOURCES) {

             _read.pending = false;

-            return;

+            return true;

         } else if (err != ERROR_MORE_DATA) {

             vd_printf("GetOverlappedResult failed: %lu", err);

-            return;

+            return false;

         }

     }

     _read.end = _read.ring + (_read.end - _read.ring + bytes) % BUF_SIZE;

     _read.bytes = bytes;

     _read.pending = false;

+    return true;

 }

diff --git a/vdservice/virtio_vdi_port.h b/vdservice/virtio_vdi_port.h
index 15b6811..d72edf4 100644
--- a/vdservice/virtio_vdi_port.h
+++ b/vdservice/virtio_vdi_port.h
@@ -17,13 +17,13 @@ public:
     virtual bool init();

     virtual unsigned get_num_events() { return VIRTIO_VDI_PORT_EVENT_COUNT; }

     virtual void fill_events(HANDLE* handles);

-    virtual void handle_event(int event);

+    virtual bool handle_event(int event);

     virtual int write();

     virtual int read();

 

 private:

-    void write_completion();

-    void read_completion();

+    bool write_completion();

+    bool read_completion();

 

 private:

     static VirtioVDIPort* _singleton;