[Teton] Load a font file and write a character to the screen.

lib/glacier/container/hash_map.h

@@ -6,6 +6,7 @@
 #include "glacier/container/linked_list.h"
 #include "glacier/container/pair.h"
 #include "glacier/status/error.h"
+#include "glacier/string/string.h"
 
 namespace glcr {
 
@@ -22,6 +23,18 @@ struct HashFunc<uint64_t> {
   }
 };
 
+template <>
+struct HashFunc<String> {
+  uint64_t operator()(const String& value) {
+    // FIXME: Write a real hash function.
+    uint64_t acc = 0;
+    for (uint64_t i = 0; i < value.length(); i++) {
+      acc += value[i];
+    }
+    return 0xABBAABBAABBAABBA ^ acc;
+  }
+};
+
 template <typename K, typename V, class H = HashFunc<K>>
 class HashMap {
  public:

lib/glacier/string/string.cpp

@@ -28,6 +28,46 @@ String::String(const char* cstr, uint64_t str_len) : length_(str_len) {
 
 String::String(StringView str) : String(str.data(), str.size()) {}
 
+String::String(const String& other) : String(other.cstr_, other.length_) {}
+
+String& String::operator=(const String& other) {
+  if (cstr_) {
+    delete cstr_;
+  }
+  length_ = other.length_;
+  cstr_ = new char[length_ + 1];
+  for (uint64_t i = 0; i < length_; i++) {
+    cstr_[i] = other.cstr_[i];
+  }
+  cstr_[length_] = '\0';
+
+  return *this;
+}
+
+String::String(String&& other) : cstr_(other.cstr_), length_(other.length_) {
+  other.cstr_ = nullptr;
+  other.length_ = 0;
+}
+
+String& String::operator=(String&& other) {
+  if (cstr_) {
+    delete cstr_;
+  }
+  cstr_ = other.cstr_;
+  length_ = other.length_;
+
+  other.cstr_ = nullptr;
+  other.length_ = 0;
+
+  return *this;
+}
+
+String::~String() {
+  if (cstr_) {
+    delete cstr_;
+  }
+}
+
 bool String::operator==(const String& other) {
   if (other.length_ != length_) {
     return false;

lib/glacier/string/string.h

@@ -13,7 +13,12 @@ class String {
   String(const char* cstr, uint64_t str_len);
   String(StringView str);
 
-  String(const String&) = delete;
+  String(const String&);
+  String& operator=(const String&);
+  String(String&&);
+  String& operator=(String&&);
+
+  ~String();
 
   const char* cstr() const { return cstr_; }
   uint64_t length() const { return length_; }

sys/teton/CMakeLists.txt

@@ -1,5 +1,6 @@
 add_executable(teton
   framebuffer/framebuffer.cpp
+  framebuffer/psf.cpp
   teton.cpp
   )
 
@@ -10,6 +11,7 @@ target_include_directories(teton
 target_link_libraries(teton
   glacier
   mammoth
+  victoriafalls_yunq
   yellowstone_yunq
   )
 

sys/teton/framebuffer/framebuffer.cpp

@@ -1,6 +1,7 @@
 #include "framebuffer/framebuffer.h"
 
-Framebuffer::Framebuffer(const FramebufferInfo& info) : fb_info_(info) {
+Framebuffer::Framebuffer(const FramebufferInfo& info)
+    : fb_info_(info), cursor_pos_(0) {
   uint64_t buff_size_bytes = fb_info_.height() * fb_info_.pitch();
   fb_memory_ = OwnedMemoryRegion::DirectPhysical(fb_info_.address_phys(),
                                                  buff_size_bytes);
@@ -11,3 +12,18 @@ void Framebuffer::DrawPixel(uint32_t row, uint32_t col, uint32_t pixel) {
   // Div by 4 because pitch is in bytes and fb_ is a 32bit array.
   fb_[(row * fb_info_.pitch() / 4) + col] = pixel;
 }
+
+void Framebuffer::DrawGlyph(uint8_t* glyph) {
+  uint32_t gl_width = 8;
+  uint32_t gl_height = 16;
+
+  for (uint8_t r = 0; r < gl_height; r++) {
+    for (uint8_t c = 0; c < gl_width; c++) {
+      if (((glyph[r] >> c) % 2) == 1) {
+        DrawPixel(r, gl_width - c - 1, 0xFFFF'FFFF);
+      } else {
+        DrawPixel(r, gl_width - c - 1, 0);
+      }
+    }
+  }
+};

sys/teton/framebuffer/framebuffer.h

@@ -9,6 +9,8 @@ class Framebuffer {
 
   void DrawPixel(uint32_t row, uint32_t col, uint32_t pixel);
 
+  void DrawGlyph(uint8_t* glyph);
+
  private:
   // FIXME: Implement Yunq copy or move so we
   // don't have to store a reference here.
@@ -16,4 +18,5 @@ class Framebuffer {
 
   OwnedMemoryRegion fb_memory_;
   uint32_t* fb_;
+  uint32_t cursor_pos_;
 };

sys/teton/framebuffer/psf.cpp

@@ -0,0 +1,46 @@
+#include "framebuffer/psf.h"
+
+#include <glacier/memory/move.h>
+#include <mammoth/debug.h>
+
+namespace {
+
+const uint32_t kMagic = 0x864AB572;
+
+}
+
+Psf::Psf(OwnedMemoryRegion&& psf_file)
+    : psf_file_(glcr::Move(psf_file)),
+      header_(reinterpret_cast<PsfHeader*>(psf_file_.vaddr())) {
+  EnsureValid();
+}
+
+void Psf::DumpHeader() {
+  dbgln("Magic: {x}", header_->magic);
+  dbgln("Version: {x}", header_->version);
+  dbgln("Header Sz: {x}", header_->headersize);
+  dbgln("Flags: {x}", header_->flags);
+  dbgln("Length: {x}", header_->numglyph);
+  dbgln("Glyph Size: {x}", header_->bytesperglyph);
+  dbgln("Height: {x}", header_->height);
+  dbgln("Width: {x}", header_->width);
+}
+
+void Psf::EnsureValid() {
+  if (header_->magic != kMagic) {
+    dbgln("PSF: Magic value: {x}", header_->magic);
+    crash("PSF: Invalid magic value", glcr::INVALID_ARGUMENT);
+  }
+
+  if (header_->version != 0) {
+    crash("PSF non-zero version", glcr::INVALID_ARGUMENT);
+  }
+
+  if (header_->height != 0x10) {
+    crash("PSF height other than 16 not handled", glcr::UNIMPLEMENTED);
+  }
+
+  if (header_->width != 0x8) {
+    crash("PSF width other than 8 not handled", glcr::UNIMPLEMENTED);
+  }
+}

sys/teton/framebuffer/psf.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <mammoth/memory_region.h>
+
+struct PsfHeader {
+  uint32_t magic;         /* magic bytes to identify PSF */
+  uint32_t version;       /* zero */
+  uint32_t headersize;    /* offset of bitmaps in file, 32 */
+  uint32_t flags;         /* 0 if there's no unicode table */
+  uint32_t numglyph;      /* number of glyphs */
+  uint32_t bytesperglyph; /* size of each glyph */
+  uint32_t height;        /* height in pixels */
+  uint32_t width;         /* width in pixels */
+};
+
+class Psf {
+ public:
+  Psf(OwnedMemoryRegion&& psf_file);
+
+  void DumpHeader();
+
+  uint32_t size() { return header_->numglyph; }
+
+  uint8_t* glyph(uint32_t index) {
+    return reinterpret_cast<uint8_t*>(psf_file_.vaddr() + header_->headersize +
+                                      (index * header_->bytesperglyph));
+  }
+
+ private:
+  OwnedMemoryRegion psf_file_;
+  PsfHeader* header_;
+
+  void EnsureValid();
+};

sys/teton/teton.cpp

@@ -1,8 +1,10 @@
 #include <mammoth/debug.h>
 #include <mammoth/init.h>
+#include <victoriafalls/victoriafalls.yunq.client.h>
 #include <yellowstone/yellowstone.yunq.client.h>
 
 #include "framebuffer/framebuffer.h"
+#include "framebuffer/psf.h"
 
 uint64_t main(uint64_t init_port) {
   ParseInitPort(init_port);
@@ -28,6 +30,23 @@ uint64_t main(uint64_t init_port) {
 
   // 2. Parse a font file.
 
+  GetEndpointRequest req;
+  req.set_endpoint_name("victoriafalls");
+  Endpoint resp;
+  check(client.GetEndpoint(req, resp));
+
+  VFSClient vfs(resp.endpoint());
+
+  OpenFileRequest freq;
+  freq.set_path("/default8x16.psfu");
+  OpenFileResponse fresp;
+  check(vfs.OpenFile(freq, fresp));
+
+  Psf psf(OwnedMemoryRegion::FromCapability(fresp.memory()));
+  psf.DumpHeader();
+
+  fbuf.DrawGlyph(psf.glyph('C'));
+
   // 3. Write a line to the screen.
 
   return 0;

sys/yellowstone/lib/yellowstone/yellowstone.yunq

@@ -1,5 +1,6 @@
 interface Yellowstone {
   method RegisterEndpoint(RegisterEndpointRequest) -> (Empty);
+  method GetEndpoint(GetEndpointRequest) -> (Endpoint);
   method GetAhciInfo(Empty) -> (AhciInfo);
   method GetFramebufferInfo(Empty) -> (FramebufferInfo);
   method GetDenali(Empty) -> (DenaliInfo);
@@ -14,6 +15,14 @@ message Empty {
 
 }
 
+message GetEndpointRequest {
+  string endpoint_name;
+}
+
+message Endpoint {
+  capability endpoint;
+}
+
 message AhciInfo {
   capability ahci_region;
   u64 region_length;

sys/yellowstone/lib/yellowstone/yellowstone.yunq.client.cpp

@@ -40,7 +40,7 @@ glcr::ErrorCode YellowstoneClient::RegisterEndpoint(const RegisterEndpointReques
 
 
 
-glcr::ErrorCode YellowstoneClient::GetAhciInfo(const Empty& request, AhciInfo& response) {
+glcr::ErrorCode YellowstoneClient::GetEndpoint(const GetEndpointRequest& request, Endpoint& response) {
   uint64_t buffer_size = kBufferSize;
   uint64_t cap_size = kCapBufferSize;
 
@@ -72,7 +72,7 @@ glcr::ErrorCode YellowstoneClient::GetAhciInfo(const Empty& request, AhciInfo& r
 
 
 
-glcr::ErrorCode YellowstoneClient::GetFramebufferInfo(const Empty& request, FramebufferInfo& response) {
+glcr::ErrorCode YellowstoneClient::GetAhciInfo(const Empty& request, AhciInfo& response) {
   uint64_t buffer_size = kBufferSize;
   uint64_t cap_size = kCapBufferSize;
 
@@ -104,7 +104,7 @@ glcr::ErrorCode YellowstoneClient::GetFramebufferInfo(const Empty& request, Fram
 
 
 
-glcr::ErrorCode YellowstoneClient::GetDenali(const Empty& request, DenaliInfo& response) {
+glcr::ErrorCode YellowstoneClient::GetFramebufferInfo(const Empty& request, FramebufferInfo& response) {
   uint64_t buffer_size = kBufferSize;
   uint64_t cap_size = kCapBufferSize;
 
@@ -135,3 +135,35 @@ glcr::ErrorCode YellowstoneClient::GetDenali(const Empty& request, DenaliInfo& r
 }
 
 
+
+glcr::ErrorCode YellowstoneClient::GetDenali(const Empty& request, DenaliInfo& response) {
+  uint64_t buffer_size = kBufferSize;
+  uint64_t cap_size = kCapBufferSize;
+
+  const uint32_t kSentinel = 0xBEEFDEAD;
+  buffer_.WriteAt<uint32_t>(0, kSentinel);
+  buffer_.WriteAt<uint64_t>(8, 4);
+
+  cap_buffer_.Reset();
+  uint64_t length = request.SerializeToBytes(buffer_, /*offset=*/16, cap_buffer_);
+  buffer_.WriteAt<uint32_t>(4, 16 + length);
+
+  z_cap_t reply_port_cap;
+  RET_ERR(ZEndpointSend(endpoint_, 16 + length, buffer_.RawPtr(), cap_buffer_.UsedSlots(), cap_buffer_.RawPtr(), &reply_port_cap)); 
+
+  // FIXME: Add a way to zero out the first buffer.
+  RET_ERR(ZReplyPortRecv(reply_port_cap, &buffer_size, buffer_.RawPtr(), &cap_size, cap_buffer_.RawPtr()));
+
+  if (buffer_.At<uint32_t>(0) != kSentinel) {
+    return glcr::INVALID_RESPONSE;
+  }
+
+  // Check Response Code.
+  RET_ERR(buffer_.At<uint64_t>(8));
+
+  response.ParseFromBytes(buffer_, 16, cap_buffer_);
+
+  return glcr::OK;
+}
+
+

sys/yellowstone/lib/yellowstone/yellowstone.yunq.client.h

@@ -19,6 +19,8 @@ class YellowstoneClient {
 
   [[nodiscard]] glcr::ErrorCode RegisterEndpoint(const RegisterEndpointRequest& request, Empty& response);
 
+  [[nodiscard]] glcr::ErrorCode GetEndpoint(const GetEndpointRequest& request, Endpoint& response);
+
   [[nodiscard]] glcr::ErrorCode GetAhciInfo(const Empty& request, AhciInfo& response);
 
   [[nodiscard]] glcr::ErrorCode GetFramebufferInfo(const Empty& request, FramebufferInfo& response);

sys/yellowstone/lib/yellowstone/yellowstone.yunq.cpp

@@ -134,6 +134,113 @@ uint64_t Empty::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr:
 
   return next_extension;
 }
+void GetEndpointRequest::ParseFromBytes(const glcr::ByteBuffer& bytes, uint64_t offset) {
+  ParseFromBytesInternal(bytes, offset);
+}
+
+void GetEndpointRequest::ParseFromBytes(const glcr::ByteBuffer& bytes, uint64_t offset, const glcr::CapBuffer& caps) {
+  ParseFromBytesInternal(bytes, offset);
+}
+
+void GetEndpointRequest::ParseFromBytesInternal(const glcr::ByteBuffer& bytes, uint64_t offset) {
+  CheckHeader(bytes);
+  // Parse endpoint_name.
+  auto endpoint_name_pointer = bytes.At<ExtPointer>(offset + header_size + (8 * 0));
+
+  set_endpoint_name(bytes.StringAt(offset + endpoint_name_pointer.offset, endpoint_name_pointer.length));
+
+}
+
+uint64_t GetEndpointRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
+  uint32_t next_extension = header_size + 8 * 1;
+  const uint32_t core_size = next_extension;
+  // Write endpoint_name.
+  ExtPointer endpoint_name_ptr{
+    .offset = next_extension,
+    // FIXME: Check downcast of str length.
+    .length = (uint32_t)endpoint_name().length(),
+  };
+
+  bytes.WriteStringAt(offset + next_extension, endpoint_name());
+  next_extension += endpoint_name_ptr.length;
+
+  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), endpoint_name_ptr);
+
+  // The next extension pointer is the length of the message. 
+  WriteHeader(bytes, offset, core_size, next_extension);
+
+  return next_extension;
+}
+
+uint64_t GetEndpointRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
+  uint32_t next_extension = header_size + 8 * 1;
+  const uint32_t core_size = next_extension;
+  uint64_t next_cap = 0;
+  // Write endpoint_name.
+  ExtPointer endpoint_name_ptr{
+    .offset = next_extension,
+    // FIXME: Check downcast of str length.
+    .length = (uint32_t)endpoint_name().length(),
+  };
+
+  bytes.WriteStringAt(offset + next_extension, endpoint_name());
+  next_extension += endpoint_name_ptr.length;
+
+  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), endpoint_name_ptr);
+
+  // The next extension pointer is the length of the message. 
+  WriteHeader(bytes, offset, core_size, next_extension);
+
+  return next_extension;
+}
+void Endpoint::ParseFromBytes(const glcr::ByteBuffer& bytes, uint64_t offset) {
+  ParseFromBytesInternal(bytes, offset);
+  // Parse endpoint.
+  // FIXME: Implement in-buffer capabilities for inprocess serialization.
+  set_endpoint(0);
+}
+
+void Endpoint::ParseFromBytes(const glcr::ByteBuffer& bytes, uint64_t offset, const glcr::CapBuffer& caps) {
+  ParseFromBytesInternal(bytes, offset);
+  // Parse endpoint.
+  uint64_t endpoint_ptr = bytes.At<uint64_t>(offset + header_size + (8 * 0));
+
+  set_endpoint(caps.At(endpoint_ptr));
+}
+
+void Endpoint::ParseFromBytesInternal(const glcr::ByteBuffer& bytes, uint64_t offset) {
+  CheckHeader(bytes);
+  // Parse endpoint.
+  // Skip Cap.
+
+}
+
+uint64_t Endpoint::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
+  uint32_t next_extension = header_size + 8 * 1;
+  const uint32_t core_size = next_extension;
+  // Write endpoint.
+  // FIXME: Implement inbuffer capabilities.
+  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), 0);
+
+  // The next extension pointer is the length of the message. 
+  WriteHeader(bytes, offset, core_size, next_extension);
+
+  return next_extension;
+}
+
+uint64_t Endpoint::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
+  uint32_t next_extension = header_size + 8 * 1;
+  const uint32_t core_size = next_extension;
+  uint64_t next_cap = 0;
+  // Write endpoint.
+  caps.WriteAt(next_cap, endpoint());
+  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), next_cap++);
+
+  // The next extension pointer is the length of the message. 
+  WriteHeader(bytes, offset, core_size, next_extension);
+
+  return next_extension;
+}
 void AhciInfo::ParseFromBytes(const glcr::ByteBuffer& bytes, uint64_t offset) {
   ParseFromBytesInternal(bytes, offset);
   // Parse ahci_region.

sys/yellowstone/lib/yellowstone/yellowstone.yunq.h

@@ -46,6 +46,46 @@ class Empty {
   // Parses everything except for caps.
   void ParseFromBytesInternal(const glcr::ByteBuffer&, uint64_t offset);
 };
+class GetEndpointRequest {
+ public:
+  GetEndpointRequest() {}
+  // Delete copy and move until implemented.
+  GetEndpointRequest(const GetEndpointRequest&) = delete;
+  GetEndpointRequest(GetEndpointRequest&&) = delete;
+
+  void ParseFromBytes(const glcr::ByteBuffer&, uint64_t offset); 
+  void ParseFromBytes(const glcr::ByteBuffer&, uint64_t offset, const glcr::CapBuffer&);
+  uint64_t SerializeToBytes(glcr::ByteBuffer&, uint64_t offset) const;
+  uint64_t SerializeToBytes(glcr::ByteBuffer&, uint64_t offset, glcr::CapBuffer&) const; 
+  const glcr::String& endpoint_name() const { return endpoint_name_; }
+  void set_endpoint_name(const glcr::String& value) { endpoint_name_ = value; }
+
+ private:
+  glcr::String endpoint_name_;
+
+  // Parses everything except for caps.
+  void ParseFromBytesInternal(const glcr::ByteBuffer&, uint64_t offset);
+};
+class Endpoint {
+ public:
+  Endpoint() {}
+  // Delete copy and move until implemented.
+  Endpoint(const Endpoint&) = delete;
+  Endpoint(Endpoint&&) = delete;
+
+  void ParseFromBytes(const glcr::ByteBuffer&, uint64_t offset); 
+  void ParseFromBytes(const glcr::ByteBuffer&, uint64_t offset, const glcr::CapBuffer&);
+  uint64_t SerializeToBytes(glcr::ByteBuffer&, uint64_t offset) const;
+  uint64_t SerializeToBytes(glcr::ByteBuffer&, uint64_t offset, glcr::CapBuffer&) const; 
+  const z_cap_t& endpoint() const { return endpoint_; }
+  void set_endpoint(const z_cap_t& value) { endpoint_ = value; }
+
+ private:
+  z_cap_t endpoint_;
+
+  // Parses everything except for caps.
+  void ParseFromBytesInternal(const glcr::ByteBuffer&, uint64_t offset);
+};
 class AhciInfo {
  public:
   AhciInfo() {}

sys/yellowstone/lib/yellowstone/yellowstone.yunq.server.cpp

@@ -98,6 +98,17 @@ glcr::ErrorCode YellowstoneServerBase::HandleRequest(const glcr::ByteBuffer& req
       break;
     }
     case 1: {
+      GetEndpointRequest yunq_request;
+      Endpoint yunq_response;
+
+      yunq_request.ParseFromBytes(request, kHeaderSize, req_caps);
+
+      RET_ERR(HandleGetEndpoint(yunq_request, yunq_response));
+
+      resp_length = yunq_response.SerializeToBytes(response, kHeaderSize, resp_caps);
+      break;
+    }
+    case 2: {
       Empty yunq_request;
       AhciInfo yunq_response;
 
@@ -108,7 +119,7 @@ glcr::ErrorCode YellowstoneServerBase::HandleRequest(const glcr::ByteBuffer& req
       resp_length = yunq_response.SerializeToBytes(response, kHeaderSize, resp_caps);
       break;
     }
-    case 2: {
+    case 3: {
       Empty yunq_request;
       FramebufferInfo yunq_response;
 
@@ -119,7 +130,7 @@ glcr::ErrorCode YellowstoneServerBase::HandleRequest(const glcr::ByteBuffer& req
       resp_length = yunq_response.SerializeToBytes(response, kHeaderSize, resp_caps);
       break;
     }
-    case 3: {
+    case 4: {
       Empty yunq_request;
       DenaliInfo yunq_response;
 

sys/yellowstone/lib/yellowstone/yellowstone.yunq.server.h

@@ -23,6 +23,8 @@ class YellowstoneServerBase {
 
   [[nodiscard]] virtual glcr::ErrorCode HandleRegisterEndpoint(const RegisterEndpointRequest&, Empty&) = 0;
 
+  [[nodiscard]] virtual glcr::ErrorCode HandleGetEndpoint(const GetEndpointRequest&, Endpoint&) = 0;
+
   [[nodiscard]] virtual glcr::ErrorCode HandleGetAhciInfo(const Empty&, AhciInfo&) = 0;
 
   [[nodiscard]] virtual glcr::ErrorCode HandleGetFramebufferInfo(const Empty&, FramebufferInfo&) = 0;

sys/yellowstone/yellowstone_server.cpp

@@ -82,8 +82,11 @@ glcr::ErrorCode YellowstoneServer::HandleGetFramebufferInfo(
 
 glcr::ErrorCode YellowstoneServer::HandleGetDenali(const Empty&,
                                                    DenaliInfo& info) {
+  if (!endpoint_map_.Contains("denali")) {
+    return glcr::NOT_FOUND;
+  }
   z_cap_t new_denali;
-  check(ZCapDuplicate(denali_cap_, kZionPerm_All, &new_denali));
+  check(ZCapDuplicate(endpoint_map_.at("denali"), kZionPerm_All, &new_denali));
   info.set_denali_endpoint(new_denali);
   info.set_device_id(device_id_);
   info.set_lba_offset(lba_offset_);
@@ -93,11 +96,9 @@ glcr::ErrorCode YellowstoneServer::HandleGetDenali(const Empty&,
 glcr::ErrorCode YellowstoneServer::HandleRegisterEndpoint(
     const RegisterEndpointRequest& req, Empty&) {
   dbgln("Registering {}.", req.endpoint_name().view());
+  check(endpoint_map_.Insert(req.endpoint_name(), req.endpoint_capability()));
   if (req.endpoint_name() == "denali") {
-    // FIXME: Rather than blocking and calling the denali service
-    // immediately we should signal the main thread that it can continue init.
-    denali_cap_ = req.endpoint_capability();
-    auto part_info_or = HandleDenaliRegistration(denali_cap_);
+    auto part_info_or = HandleDenaliRegistration(req.endpoint_capability());
     if (!part_info_or.ok()) {
       check(part_info_or.error());
     }
@@ -106,10 +107,9 @@ glcr::ErrorCode YellowstoneServer::HandleRegisterEndpoint(
 
     check(has_denali_mutex_.Release());
   } else if (req.endpoint_name() == "victoriafalls") {
-    victoria_falls_cap_ = req.endpoint_capability();
     // FIXME: Probably make a separate copy for use within yellowstone vs
     // transmit to other processes.
-    vfs_client_ = glcr::MakeShared<VFSClient>(victoria_falls_cap_);
+    vfs_client_ = glcr::MakeShared<VFSClient>(req.endpoint_capability());
     check(has_victoriafalls_mutex_.Release());
   } else {
     dbgln("[WARN] Got endpoint cap type: {}", req.endpoint_name().cstr());
@@ -117,6 +117,18 @@ glcr::ErrorCode YellowstoneServer::HandleRegisterEndpoint(
   return glcr::OK;
 }
 
+glcr::ErrorCode YellowstoneServer::HandleGetEndpoint(
+    const GetEndpointRequest& req, Endpoint& resp) {
+  if (!endpoint_map_.Contains(req.endpoint_name())) {
+    return glcr::NOT_FOUND;
+  }
+  z_cap_t cap = endpoint_map_.at(req.endpoint_name());
+  z_cap_t new_cap;
+  check(ZCapDuplicate(cap, kZionPerm_All, &new_cap));
+  resp.set_endpoint(new_cap);
+  return glcr::OK;
+}
+
 glcr::ErrorCode YellowstoneServer::WaitDenaliRegistered() {
   RET_ERR(has_denali_mutex_.Lock());
   return has_denali_mutex_.Release();

sys/yellowstone/yellowstone_server.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <glacier/container/hash_map.h>
 #include <glacier/memory/shared_ptr.h>
 #include <glacier/memory/unique_ptr.h>
 #include <glacier/status/error_or.h>
@@ -22,6 +23,8 @@ class YellowstoneServer : public YellowstoneServerBase {
   glcr::ErrorCode HandleGetDenali(const Empty&, DenaliInfo&) override;
   glcr::ErrorCode HandleRegisterEndpoint(const RegisterEndpointRequest&,
                                          Empty&) override;
+  glcr::ErrorCode HandleGetEndpoint(const GetEndpointRequest&,
+                                    Endpoint&) override;
 
   glcr::ErrorCode WaitDenaliRegistered();
   glcr::ErrorCode WaitVictoriaFallsRegistered();
@@ -29,11 +32,10 @@ class YellowstoneServer : public YellowstoneServerBase {
   glcr::SharedPtr<VFSClient> GetVFSClient();
 
  private:
-  // TODO: Store these in a data structure.
-  z_cap_t denali_cap_ = 0;
+  glcr::HashMap<glcr::String, z_cap_t> endpoint_map_;
+
   uint64_t device_id_ = 0;
   uint64_t lba_offset_ = 0;
-  z_cap_t victoria_falls_cap_ = 0;
   glcr::SharedPtr<VFSClient> vfs_client_;
 
   PciReader pci_reader_;