[lldb] [lldb-gdbserver] Unify listen/connect code to use ConnectionFileDescriptor

Unify the listen and connect code inside lldb-server to use
ConnectionFileDescriptor uniformly rather than a mix of it and Acceptor.
This involves:

- adding a function to map legacy values of host:port parameter
  (including legacy server URLs) into CFD-style URLs

- adding a callback to return "local socket id" (i.e. UNIX socket path
  or TCP port number) between listen() and accept() calls in CFD

- adding a "unix-abstract-accept" scheme to CFD

As an additional advantage, this permits lldb-server to accept any URL
known to CFD including the new serial:// scheme.  Effectively,
lldb-server can now listen on the serial port.  Tests for connecting
over a pty are added to test that.

Differential Revision: https://reviews.llvm.org/D111964

1 files changed, 41 insertions, 0 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index b1e9e3c..27acf7e 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -25,6 +25,7 @@
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
 #include "lldb/Host/PosixApi.h"
+#include "lldb/Host/Socket.h"
 #include "lldb/Host/common/NativeProcessProtocol.h"
 #include "lldb/Host/common/NativeRegisterContext.h"
 #include "lldb/Host/common/NativeThreadProtocol.h"
@@ -39,6 +40,7 @@
 #include "lldb/Utility/State.h"
 #include "lldb/Utility/StreamString.h"
 #include "lldb/Utility/UnimplementedError.h"
+#include "lldb/Utility/UriParser.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/JSON.h"
 #include "llvm/Support/ScopedPrinter.h"
@@ -3888,3 +3890,42 @@ void GDBRemoteCommunicationServerLLGS::SetEnabledExtensions(
   assert(!bool(flags & ~m_process_factory.GetSupportedExtensions()));
   process.SetEnabledExtensions(flags);
 }
+
+std::string
+lldb_private::process_gdb_remote::LLGSArgToURL(llvm::StringRef url_arg,
+                                               bool reverse_connect) {
+  // Try parsing the argument as URL.
+  if (llvm::Optional<URI> url = URI::Parse(url_arg)) {
+    if (reverse_connect)
+      return url_arg.str();
+
+    // Translate the scheme from LLGS notation to ConnectionFileDescriptor.
+    // If the scheme doesn't match any, pass it through to support using CFD
+    // schemes directly.
+    std::string new_url = llvm::StringSwitch<std::string>(url->scheme)
+                              .Case("tcp", "listen")
+                              .Case("unix", "unix-accept")
+                              .Case("unix-abstract", "unix-abstract-accept")
+                              .Default(url->scheme.str());
+    llvm::append_range(new_url, url_arg.substr(url->scheme.size()));
+    return new_url;
+  }
+
+  std::string host_port = url_arg.str();
+  // If host_and_port starts with ':', default the host to be "localhost" and
+  // expect the remainder to be the port.
+  if (url_arg.startswith(":"))
+    host_port.insert(0, "localhost");
+
+  std::string host_str;
+  std::string port_str;
+  uint16_t port;
+  // Try parsing the (preprocessed) argument as host:port pair.
+  if (!llvm::errorToBool(
+          Socket::DecodeHostAndPort(host_port, host_str, port_str, port)))
+    return (reverse_connect ? "connect://" : "listen://") + host_port;
+
+  // If none of the above applied, interpret the argument as UNIX socket path.
+  return (reverse_connect ? "unix-connect://" : "unix-accept://") +
+         url_arg.str();
+}