[all] Add stub for new Endpoint kernel object

lib/mammoth/CMakeLists.txt

@@ -1,6 +1,8 @@
 add_library(mammoth_lib STATIC
   src/channel.cpp
   src/debug.cpp
+  src/endpoint_client.cpp
+  src/endpoint_server.cpp
   src/init.cpp
   src/memory_region.cpp
   src/process.cpp

lib/mammoth/include/mammoth/endpoint_client.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include <glacier/container/pair.h>
+#include <glacier/status/error_or.h>
+#include <zcall.h>
+#include <ztypes.h>
+
+class EndpointClient {
+ public:
+  static EndpointClient AdoptEndpoint(z_cap_t cap);
+
+  template <typename Req, typename Resp>
+  glcr::ErrorOr<glcr::Pair<Resp, z_cap_t>> CallEndpoint(const Req& req);
+
+ private:
+  EndpointClient(uint64_t cap) : cap_(cap) {}
+  z_cap_t cap_;
+};
+
+template <typename Req, typename Resp>
+glcr::ErrorOr<glcr::Pair<Resp, z_cap_t>> EndpointClient::CallEndpoint(
+    const Req& req) {
+  uint64_t reply_port_cap;
+  RET_ERR(ZEndpointSend(cap_, sizeof(Req), &req, &reply_port_cap));
+
+  Resp resp;
+  z_cap_t cap = 0;
+  uint64_t num_caps = 1;
+  uint64_t num_bytes = sizeof(Resp);
+  RET_ERR(ZReplyPortRecv(reply_port_cap, &num_bytes, &resp, &num_caps, &cap));
+
+  if (num_bytes != sizeof(resp) || num_caps != 1) {
+    return glcr::FAILED_PRECONDITION;
+  }
+
+  return glcr::Pair{resp, cap};
+}

lib/mammoth/include/mammoth/endpoint_server.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <glacier/status/error_or.h>
+#include <ztypes.h>
+
+#include "mammoth/endpoint_client.h"
+
+class EndpointServer {
+ public:
+  static glcr::ErrorOr<EndpointServer> Create();
+  static EndpointServer Adopt(z_cap_t endpoint_cap);
+
+  glcr::ErrorOr<EndpointClient> CreateClient();
+
+  // FIXME: Release Cap here.
+  z_cap_t GetCap() { return endpoint_cap_; }
+
+ private:
+  z_cap_t endpoint_cap_;
+
+  EndpointServer(z_cap_t cap) : endpoint_cap_(cap) {}
+};

lib/mammoth/include/mammoth/process.h

@@ -3,6 +3,6 @@
 #include <glacier/status/error_or.h>
 #include <stdint.h>
 
-#include "mammoth/channel.h"
+#include "mammoth/endpoint_client.h"
 
-glcr::ErrorOr<Channel> SpawnProcessFromElfRegion(uint64_t program);
+glcr::ErrorOr<EndpointClient> SpawnProcessFromElfRegion(uint64_t program);

lib/mammoth/src/endpoint_client.cpp

@@ -0,0 +1,3 @@
+#include "mammoth/endpoint_server.h"
+
+EndpointClient EndpointClient::AdoptEndpoint(z_cap_t cap) { return {cap}; }

lib/mammoth/src/endpoint_server.cpp

@@ -0,0 +1,14 @@
+#include "mammoth/endpoint_server.h"
+
+glcr::ErrorOr<EndpointServer> EndpointServer::Create() {
+  uint64_t cap;
+  RET_ERR(ZEndpointCreate(&cap));
+  return EndpointServer(cap);
+}
+
+glcr::ErrorOr<EndpointClient> EndpointServer::CreateClient() {
+  uint64_t client_cap;
+  // FIXME: Restrict permissions to send-only here.
+  RET_ERR(ZCapDuplicate(endpoint_cap_, &client_cap));
+  return EndpointClient::AdoptEndpoint(client_cap);
+}

lib/mammoth/src/process.cpp

@@ -3,8 +3,8 @@
 #include <glacier/status/error.h>
 #include <zcall.h>
 
-#include "mammoth/channel.h"
 #include "mammoth/debug.h"
+#include "mammoth/endpoint_server.h"
 #include "mammoth/init.h"
 #include "mammoth/port.h"
 
@@ -95,20 +95,21 @@ uint64_t LoadElfProgram(uint64_t base, uint64_t as_cap) {
 
 }  // namespace
 
-glcr::ErrorOr<Channel> SpawnProcessFromElfRegion(uint64_t program) {
-  Channel local, foreign;
-  check(CreateChannels(local, foreign));
+glcr::ErrorOr<EndpointClient> SpawnProcessFromElfRegion(uint64_t program) {
+  ASSIGN_OR_RETURN(EndpointServer server, EndpointServer::Create());
+  ASSIGN_OR_RETURN(EndpointClient client, server.CreateClient());
 
   uint64_t proc_cap;
   uint64_t as_cap;
   uint64_t foreign_port_id;
   uint64_t port_cap;
+
 #if MAM_PROC_DEBUG
   dbgln("Port Create");
 #endif
-  check(ZPortCreate(&port_cap));
+  RET_ERR(ZPortCreate(&port_cap));
   uint64_t port_cap_donate;
-  check(ZCapDuplicate(port_cap, &port_cap_donate));
+  RET_ERR(ZCapDuplicate(port_cap, &port_cap_donate));
 
 #if MAM_PROC_DEBUG
   dbgln("Spawn");
@@ -127,12 +128,12 @@ glcr::ErrorOr<Channel> SpawnProcessFromElfRegion(uint64_t program) {
   Port p(port_cap);
   check(p.WriteMessage<uint64_t>(Z_INIT_SELF_PROC, proc_cap));
   check(p.WriteMessage<uint64_t>(Z_INIT_SELF_VMAS, as_cap));
-  check(p.WriteMessage<uint64_t>(Z_INIT_CHANNEL, foreign.release_cap()));
+  check(p.WriteMessage<uint64_t>(Z_INIT_CHANNEL, server.GetCap()));
 
 #if MAM_PROC_DEBUG
   dbgln("Thread start");
 #endif
   check(ZThreadStart(thread_cap, entry_point, foreign_port_id, 0));
 
-  return local;
+  return client;
 }