[lldb] For a host socket, add a method to print the listening address. (llvm#118330)

This is most useful if you are listening on an address like
'localhost:0' and want to know the resolved ip + port of the socket
listener.

Author: ashgti

lldb/include/lldb/Host/Socket.h

@@ -11,6 +11,7 @@
 
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "lldb/Host/MainLoopBase.h"
 #include "lldb/Utility/Timeout.h"
@@ -151,6 +152,11 @@ class Socket : public IOObject {
   // If this Socket is connected then return the URI used to connect.
   virtual std::string GetRemoteConnectionURI() const { return ""; };
 
+  // If the Socket is listening then return the URI for clients to connect.
+  virtual std::vector<std::string> GetListeningConnectionURI() const {
+    return {};
+  }
+
 protected:
   Socket(SocketProtocol protocol, bool should_close);
 

lldb/include/lldb/Host/common/TCPSocket.h

@@ -13,6 +13,8 @@
 #include "lldb/Host/Socket.h"
 #include "lldb/Host/SocketAddress.h"
 #include <map>
+#include <string>
+#include <vector>
 
 namespace lldb_private {
 class TCPSocket : public Socket {
@@ -52,6 +54,8 @@ class TCPSocket : public Socket {
 
   std::string GetRemoteConnectionURI() const override;
 
+  std::vector<std::string> GetListeningConnectionURI() const override;
+
 private:
   TCPSocket(NativeSocket socket, const TCPSocket &listen_socket);
 

lldb/include/lldb/Host/posix/DomainSocket.h

@@ -10,6 +10,8 @@
 #define LLDB_HOST_POSIX_DOMAINSOCKET_H
 
 #include "lldb/Host/Socket.h"
+#include <string>
+#include <vector>
 
 namespace lldb_private {
 class DomainSocket : public Socket {
@@ -27,6 +29,8 @@ class DomainSocket : public Socket {
 
   std::string GetRemoteConnectionURI() const override;
 
+  std::vector<std::string> GetListeningConnectionURI() const override;
+
 protected:
   DomainSocket(SocketProtocol protocol);
 

lldb/source/Host/common/TCPSocket.cpp

@@ -115,6 +115,14 @@ std::string TCPSocket::GetRemoteConnectionURI() const {
   return "";
 }
 
+std::vector<std::string> TCPSocket::GetListeningConnectionURI() const {
+  std::vector<std::string> URIs;
+  for (const auto &[fd, addr] : m_listen_sockets)
+    URIs.emplace_back(llvm::formatv("connection://[{0}]:{1}",
+                                    addr.GetIPAddress(), addr.GetPort()));
+  return URIs;
+}
+
 Status TCPSocket::CreateSocket(int domain) {
   Status error;
   if (IsValid())

lldb/source/Host/posix/DomainSocket.cpp

@@ -175,3 +175,17 @@ std::string DomainSocket::GetRemoteConnectionURI() const {
       "{0}://{1}",
       GetNameOffset() == 0 ? "unix-connect" : "unix-abstract-connect", name);
 }
+
+std::vector<std::string> DomainSocket::GetListeningConnectionURI() const {
+  if (m_socket == kInvalidSocketValue)
+    return {};
+
+  struct sockaddr_un addr;
+  bzero(&addr, sizeof(struct sockaddr_un));
+  addr.sun_family = AF_UNIX;
+  socklen_t addr_len = sizeof(struct sockaddr_un);
+  if (::getsockname(m_socket, (struct sockaddr *)&addr, &addr_len) != 0)
+    return {};
+
+  return {llvm::formatv("unix-connect://{0}", addr.sun_path)};
+}

lldb/unittests/Host/SocketTest.cpp

@@ -88,6 +88,28 @@ TEST_P(SocketTest, DomainListenConnectAccept) {
   CreateDomainConnectedSockets(Path, &socket_a_up, &socket_b_up);
 }
 
+TEST_P(SocketTest, DomainListenGetListeningConnectionURI) {
+  llvm::SmallString<64> Path;
+  std::error_code EC =
+      llvm::sys::fs::createUniqueDirectory("DomainListenConnectAccept", Path);
+  ASSERT_FALSE(EC);
+  llvm::sys::path::append(Path, "test");
+
+  // Skip the test if the $TMPDIR is too long to hold a domain socket.
+  if (Path.size() > 107u)
+    return;
+
+  auto listen_socket_up = std::make_unique<DomainSocket>(
+      /*should_close=*/true);
+  Status error = listen_socket_up->Listen(Path, 5);
+  ASSERT_THAT_ERROR(error.ToError(), llvm::Succeeded());
+  ASSERT_TRUE(listen_socket_up->IsValid());
+
+  ASSERT_THAT(
+      listen_socket_up->GetListeningConnectionURI(),
+      testing::ElementsAre(llvm::formatv("unix-connect://{0}", Path).str()));
+}
+
 TEST_P(SocketTest, DomainMainLoopAccept) {
   llvm::SmallString<64> Path;
   std::error_code EC =
@@ -225,12 +247,29 @@ TEST_P(SocketTest, TCPListen0GetPort) {
   if (!HostSupportsIPv4())
     return;
   llvm::Expected<std::unique_ptr<TCPSocket>> sock =
-      Socket::TcpListen("10.10.12.3:0", false);
+      Socket::TcpListen("10.10.12.3:0", 5);
   ASSERT_THAT_EXPECTED(sock, llvm::Succeeded());
   ASSERT_TRUE(sock.get()->IsValid());
   EXPECT_NE(sock.get()->GetLocalPortNumber(), 0);
 }
 
+TEST_P(SocketTest, TCPListen0GetListeningConnectionURI) {
+  if (!HostSupportsProtocol())
+    return;
+
+  std::string addr = llvm::formatv("[{0}]:0", GetParam().localhost_ip).str();
+  llvm::Expected<std::unique_ptr<TCPSocket>> sock = Socket::TcpListen(addr);
+  ASSERT_THAT_EXPECTED(sock, llvm::Succeeded());
+  ASSERT_TRUE(sock.get()->IsValid());
+
+  EXPECT_THAT(
+      sock.get()->GetListeningConnectionURI(),
+      testing::ElementsAre(llvm::formatv("connection://[{0}]:{1}",
+                                         GetParam().localhost_ip,
+                                         sock->get()->GetLocalPortNumber())
+                               .str()));
+}
+
 TEST_P(SocketTest, TCPGetConnectURI) {
   std::unique_ptr<TCPSocket> socket_a_up;
   std::unique_ptr<TCPSocket> socket_b_up;