[Yunq] Delete client capability in destructor.

Add a method to the server class to create an unowned capability. This
makes it simpler to create a capability for passing to other processes.

Duplicate the init yellowstone cap when using it temporarily.

sys/victoriafalls/lib/victoriafalls/victoriafalls.yunq.client.cpp

@@ -3,10 +3,18 @@
 
 #include <glacier/buffer/byte_buffer.h>
 #include <glacier/buffer/cap_buffer.h>
+#include <mammoth/util/debug.h>
 #include <zcall.h>
 
 
 
+VFSClient::~VFSClient() {
+  if (endpoint_ != 0) {
+    check(ZCapRelease(endpoint_));
+    }
+}
+
+
 
 
 glcr::ErrorCode VFSClient::OpenFile(const OpenFileRequest& request, OpenFileResponse& response) {

sys/victoriafalls/lib/victoriafalls/victoriafalls.yunq.client.h

@@ -13,6 +13,7 @@ class VFSClient {
   VFSClient(z_cap_t VFS_cap) : endpoint_(VFS_cap) {}
   VFSClient(const VFSClient&) = delete;
   VFSClient(VFSClient&& other) : endpoint_(other.endpoint_) {other.endpoint_ = 0;};
+  ~VFSClient();
 
   z_cap_t Capability() { return endpoint_; }
 

sys/victoriafalls/lib/victoriafalls/victoriafalls.yunq.server.cpp

@@ -35,6 +35,12 @@ VFSServerBase::~VFSServerBase() {
   }
 }
 
+glcr::ErrorOr<z_cap_t> VFSServerBase::CreateClientCap() {
+  uint64_t client_cap;
+  RET_ERR(ZCapDuplicate(endpoint_, ~(kZionPerm_Read), &client_cap));
+  return client_cap;
+}
+
 glcr::ErrorOr<VFSClient> VFSServerBase::CreateClient() {
   uint64_t client_cap;
   RET_ERR(ZCapDuplicate(endpoint_, ~(kZionPerm_Read), &client_cap));

sys/victoriafalls/lib/victoriafalls/victoriafalls.yunq.server.h

@@ -17,6 +17,7 @@ class VFSServerBase {
   VFSServerBase(VFSServerBase&&) = delete;
   virtual ~VFSServerBase();
 
+  glcr::ErrorOr<z_cap_t> CreateClientCap();
   glcr::ErrorOr<VFSClient> CreateClient();
 
   [[nodiscard]] Thread RunServer();