Adds support for read or write-only midi devices entries.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40419 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/midi/DeviceWatcher.cpp

@@ -13,6 +13,8 @@
 #include "DeviceWatcher.h"
 #include "PortDrivers.h"
 
+#include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <new>
 
@@ -225,24 +227,40 @@ DeviceWatcher::_AddDevice(const char* path)
 	}
 
 	int fd = open(path, O_RDWR | O_EXCL);
-	if (fd < 0)
+	if (fd < 0) {
+		if (errno != EACCES)
 			return;
 
+		// maybe it's a input or output only port?
+		fd = open(path, O_RDONLY | O_EXCL);
+		if (fd < 0 && errno == EACCES)
+			fd = open(path, O_WRONLY | O_EXCL);
+		if (fd < 0)
+			return;
+	}
 
 	TRACE(("Doing _AddDevice(\"%s\"); fd=%d\n", path, fd));
 
-	MidiPortConsumer* consumer = new MidiPortConsumer(fd, path);
+	MidiPortConsumer* consumer = NULL;
+	MidiPortProducer* producer = NULL;
+
+	int flags = fcntl(fd, F_GETFL);
+
+	if ((flags & O_ACCMODE) != O_RDONLY) {
+		consumer = new MidiPortConsumer(fd, path);
 		_SetIcons(consumer);
 		TRACE(("Register %s MidiPortConsumer\n", consumer->Name()));
 		consumer->Register();
+	}
 
-	MidiPortProducer* producer = new MidiPortProducer(fd, path);
+	if ((flags & O_ACCMODE) != O_WRONLY) {
+		producer = new MidiPortProducer(fd, path);
 		_SetIcons(producer);
 		TRACE(("Register %s MidiPortProducer\n", producer->Name()));
 		producer->Register();
+	}
 
-	DeviceEndpoints* deviceEndpoints = new DeviceEndpoints(fd, consumer, producer);
+	fDeviceEndpointsMap.Put(path, new DeviceEndpoints(fd, consumer, producer));
-	fDeviceEndpointsMap.Put(path, deviceEndpoints);	
 	TRACE(("Done _AddDevice(\"%s\")\n", path));
 }
 
@@ -259,11 +277,15 @@ DeviceWatcher::_RemoveDevice(const char* path)
 	}
 
 	TRACE((" _RemoveDevice(\"%s\") unregistering\n", path));
+	if (deviceEndpoints->fConsumer)
 		deviceEndpoints->fConsumer->Unregister();
+	if (deviceEndpoints->fProducer)
 		deviceEndpoints->fProducer->Unregister();
 
 	TRACE((" _RemoveDevice(\"%s\") releasing\n", path));
+	if (deviceEndpoints->fConsumer)
 		deviceEndpoints->fConsumer->Release();
+	if (deviceEndpoints->fProducer)
 		deviceEndpoints->fProducer->Release();
 
 	TRACE((" _RemoveDevice(\"%s\") removing from map\n", path));