Bind and connect to Unix domain sockets using relative paths (#1192)

Package.resolved

@@ -1,5 +1,5 @@
 {
-  "originHash" : "0da1cc30fa3c41e8c2e2edcdd55706549908275a54f681203e0eeade279deab9",
+  "originHash" : "061dfe6cdf4e6dbf32b51c5e7023c4ae69726dcafb42a35b34e5489b0338c17f",
   "pins" : [
     {
       "identity" : "antlr4",
@@ -49,10 +49,10 @@
     {
       "identity" : "opentelemetry-swift",
       "kind" : "remoteSourceControl",
-      "location" : "https://github.com/cirruslabs/opentelemetry-swift",
+      "location" : "https://github.com/open-telemetry/opentelemetry-swift",
       "state" : {
-        "branch" : "use-feedback-handler",
-        "revision" : "2040f383e2a8b0a568a7617d147f8f1e23abb298"
+        "branch" : "main",
+        "revision" : "ed37be9525081509ab62410d38b705c2b3f0d5a4"
       }
     },
     {

Package.swift

@@ -25,7 +25,7 @@ let package = Package(
     .package(url: "https://github.com/jozefizso/swift-xattr", from: "3.0.0"),
     .package(url: "https://github.com/grpc/grpc-swift.git", .upToNextMajor(from: "1.27.0")),
     .package(url: "https://buf.build/gen/swift/git/1.27.1-20260114140118-bd09c26a260f.1/cirruslabs_tart-guest-agent_grpc_swift.git", branch: "main"),
-    .package(url: "https://github.com/cirruslabs/opentelemetry-swift", branch: "use-feedback-handler"),
+    .package(url: "https://github.com/open-telemetry/opentelemetry-swift", branch: "main"),
     .package(url: "https://github.com/open-telemetry/opentelemetry-swift-core", from: "2.3.0"),
 
   ],

Sources/tart/Commands/Exec.swift

@@ -47,8 +47,16 @@ struct Exec: AsyncParsableCommand {
       try! group.syncShutdownGracefully()
     }
 
+    // Change the current working directory to a VM's base directory
+    // to work around Unix domain socket 104 byte limitation [1]
+    //
+    // [1]: https://blog.8-p.info/en/2020/06/11/unix-domain-socket-length/
+    if let baseURL = vmDir.controlSocketURL.baseURL {
+      FileManager.default.changeCurrentDirectoryPath(baseURL.path())
+    }
+
     let channel = try GRPCChannelPool.with(
-      target: .unixDomainSocket(vmDir.controlSocketURL.path()),
+      target: .unixDomainSocket(vmDir.controlSocketURL.relativePath),
       transportSecurity: .plaintext,
       eventLoopGroup: group,
     )

Sources/tart/Commands/IP.swift

@@ -68,7 +68,15 @@ struct IP: AsyncParsableCommand {
           throw RuntimeError.Generic("Cannot perform IP resolution via Tart Guest Agent when control socket URL is not set")
         }
 
-        if let ip = try await AgentResolver.ResolveIP(controlSocketURL) {
+        // Change the current working directory to a VM's base directory
+        // to work around Unix domain socket 104 byte limitation [1]
+        //
+        // [1]: https://blog.8-p.info/en/2020/06/11/unix-domain-socket-length/
+        if let baseURL = controlSocketURL.baseURL {
+          FileManager.default.changeCurrentDirectoryPath(baseURL.path())
+        }
+
+        if let ip = try await AgentResolver.ResolveIP(controlSocketURL.relativePath) {
           return ip
         }
       }

Sources/tart/ControlSocket.swift

@@ -21,8 +21,16 @@ class ControlSocket {
     // if any, otherwise we may get the "address already in use" error
     try? FileManager.default.removeItem(atPath: controlSocketURL.path())
 
+    // Change the current working directory to a VM's base directory
+    // to work around Unix domain socket 104 byte limitation [1]
+    //
+    // [1]: https://blog.8-p.info/en/2020/06/11/unix-domain-socket-length/
+    if let baseURL = controlSocketURL.baseURL {
+      FileManager.default.changeCurrentDirectoryPath(baseURL.path())
+    }
+
     let serverChannel = try await ServerBootstrap(group: eventLoopGroup)
-      .bind(unixDomainSocketPath: controlSocketURL.path()) { childChannel in
+      .bind(unixDomainSocketPath: controlSocketURL.relativePath) { childChannel in
         childChannel.eventLoop.makeCompletedFuture {
           return try NIOAsyncChannel<ByteBuffer, ByteBuffer>(
             wrappingChannelSynchronously: childChannel

Sources/tart/MACAddressResolver/AgentResolver.swift

@@ -6,15 +6,15 @@ import Cirruslabs_TartGuestAgent_Apple_Swift
 import Cirruslabs_TartGuestAgent_Grpc_Swift
 
 class AgentResolver {
-  static func ResolveIP(_ controlSocketURL: URL) async throws -> IPv4Address? {
+  static func ResolveIP(_ controlSocketPath: String) async throws -> IPv4Address? {
     do {
-      return try await resolveIP(controlSocketURL)
+      return try await resolveIP(controlSocketPath)
     } catch let error as GRPCConnectionPoolError {
       return nil
     }
   }
 
-  private static func resolveIP(_ controlSocketURL: URL) async throws -> IPv4Address? {
+  private static func resolveIP(_ controlSocketPath: String) async throws -> IPv4Address? {
     // Create a gRPC channel connected to the VM's control socket
     let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
     defer {
@@ -22,7 +22,7 @@ class AgentResolver {
     }
 
     let channel = try GRPCChannelPool.with(
-      target: .unixDomainSocket(controlSocketURL.path()),
+      target: .unixDomainSocket(controlSocketPath),
       transportSecurity: .plaintext,
       eventLoopGroup: group,
     )

Sources/tart/VMDirectory.swift

@@ -27,7 +27,7 @@ struct VMDirectory: Prunable {
     baseURL.appendingPathComponent("manifest.json")
   }
   var controlSocketURL: URL {
-    baseURL.appendingPathComponent("control.sock")
+    URL(fileURLWithPath: "control.sock", relativeTo: baseURL)
   }
 
   var explicitlyPulledMark: URL {