Move ConnectionFileDescriptor to posix-subfolder in preparation for implementing on Windows

[zturner]

Summary

ConnectionFileDescriptor needs a different implementation on Windows and non-Windows platforms due to some fundamental differences. This patch moves source\Core\ConnectionFileDescriptor.cpp to source\Core\posix\ConnectionFileDescriptorPosix.cpp, and similarly for the corresponding header file. Then, the original ConnectionFileDescriptor.h is replaced with a new implementation that includes the platform specific header file.

Currently this patch does not actually implement Windows' version of ConnectionFileDescriptor. It only makes the organizational changes necessary for this to happen in a subsequent patch. As such, with this patch, Windows will actually be compiling source\Core\posix\ConnectionFileDescriptor.cpp. When the windows version of CFD goes in, the CMake will be updated accordingly to compile the windows CFD.

This patch contains no functional changes, only code move.

[emaste]

I haven't looked closely at the proposed patch, but should CFD instead migrate to source/Host/...?

[zturner]

Good question. Logically it seems a little too high level for Host to me.
Conceptually speaking, CFD is just a wrapper around one of any number of
host primitives. For example, it's a wrapper around a file, or a socket,
or a pipe, etc. It just allows you to treat all those things using the
same interface. Host seems more appropriate for providing lower-level
primitives. It's kind of a grey area here though, because the
implementation of CFD uses select(), which doesn't lend itself to a nice
port on Windows, basically the whole thing has to be re-written.

I brainstormed ways of lowering a select-like abstraction into Host so that
CFD could just be implemented without any platform specific stuff, but it's
not that easy since the semantics have some subtle differences that make it
difficult to present a generic interface.

[zturner]

Same change as before, but with CFD moved to Host instead of to a platform-specific folder in Core. There's no functionality change here, just file re-organization.

[clayborg]

Looks good.

[zturner]

Closed by commit rL219143 (authored by @zturner).

include/lldb/Core/ConnectionFileDescriptor.h

 //
 //===----------------------------------------------------------------------===//
 
-#ifndef liblldb_ConnectionFileDescriptor_h_
-#define liblldb_ConnectionFileDescriptor_h_
+#ifndef liblldb_Core_ConnectionFileDescriptor_h_
+#define liblldb_Core_ConnectionFileDescriptor_h_
 
-// C++ Includes
-#include <atomic>
-#include <memory>
+#include "lldb/Core/posix/ConnectionFileDescriptorPosix.h"
 
-#include "lldb/lldb-forward.h"
-
-// Other libraries and framework includes
-// Project includes
-#include "lldb/Core/Connection.h"
-#include "lldb/Host/Mutex.h"
-#include "lldb/Host/Pipe.h"
-#include "lldb/Host/Predicate.h"
-#include "lldb/Host/IOObject.h"
-
-namespace lldb_private {
-
-class Error;
-class Socket;
-class SocketAddress;
-
-class ConnectionFileDescriptor :
-    public Connection
-{
-public:
-
-    ConnectionFileDescriptor ();
-
-    ConnectionFileDescriptor (int fd, bool owns_fd);
-
-    virtual
-    ~ConnectionFileDescriptor ();
-
-    virtual bool
-    IsConnected () const;
-
-    virtual lldb::ConnectionStatus
-    Connect (const char *s, Error *error_ptr);
-
-    virtual lldb::ConnectionStatus
-    Disconnect (Error *error_ptr);
-
-    virtual size_t
-    Read (void *dst, 
-          size_t dst_len, 
-          uint32_t timeout_usec,
-          lldb::ConnectionStatus &status, 
-          Error *error_ptr);
-
-    virtual size_t
-    Write (const void *src, 
-           size_t src_len, 
-           lldb::ConnectionStatus &status, 
-           Error *error_ptr);
-
-    lldb::ConnectionStatus
-    BytesAvailable (uint32_t timeout_usec, Error *error_ptr);
-
-    bool
-    InterruptRead ();
-
-    lldb::IOObjectSP GetReadObject() { return m_read_sp; }
-    const lldb::IOObjectSP GetReadObject() const { return m_read_sp; }
-
-    uint16_t GetListeningPort(uint32_t timeout_sec);
-
-protected:
-    
-    void
-    OpenCommandPipe ();
-    
-    void
-    CloseCommandPipe ();
-    
-    lldb::ConnectionStatus
-    SocketListen (const char *host_and_port, Error *error_ptr);
-    
-    lldb::ConnectionStatus
-    ConnectTCP (const char *host_and_port, Error *error_ptr);
-
-    lldb::ConnectionStatus
-    ConnectUDP (const char *args, Error *error_ptr);
-    
-    lldb::ConnectionStatus
-    NamedSocketConnect (const char *socket_name, Error *error_ptr);
-
-    lldb::ConnectionStatus
-    NamedSocketAccept (const char *socket_name, Error *error_ptr);
-    
-    lldb::IOObjectSP m_read_sp;
-    lldb::IOObjectSP m_write_sp;
-
-    Predicate<uint16_t> m_port_predicate; // Used when binding to port zero to wait for the thread
-                                          // that creates the socket, binds and listens to resolve
-                                          // the port number.
-
-    Pipe m_pipe;
-    Mutex m_mutex;
-    std::atomic<bool> m_shutting_down;    // This marks that we are shutting down so if we get woken up from
-                                          // BytesAvailable to disconnect, we won't try to read again.
-    bool m_waiting_for_accept;
-private:
-    DISALLOW_COPY_AND_ASSIGN (ConnectionFileDescriptor);
-};
-
-} // namespace lldb_private
-
-#endif  // liblldb_ConnectionFileDescriptor_h_
+#endif

include/lldb/Core/posix/ConnectionFileDescriptorPosix.h

+//===-- ConnectionFileDescriptorPosix.h -------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_Core_posix_ConnectionFileDescriptorPosix_h_
+#define liblldb_Core_posix_ConnectionFileDescriptorPosix_h_
+
+// C++ Includes
+#include <atomic>
+#include <memory>
+
+#include "lldb/lldb-forward.h"
+
+// Other libraries and framework includes
+// Project includes
+#include "lldb/Core/Connection.h"
+#include "lldb/Host/Mutex.h"
+#include "lldb/Host/Pipe.h"
+#include "lldb/Host/Predicate.h"
+#include "lldb/Host/IOObject.h"
+
+namespace lldb_private
+{
+
+class Error;
+class Socket;
+class SocketAddress;
+
+class ConnectionFileDescriptor : public Connection
+{
+  public:
+    ConnectionFileDescriptor();
+
+    ConnectionFileDescriptor(int fd, bool owns_fd);
+
+    virtual ~ConnectionFileDescriptor();
+
+    virtual bool IsConnected() const;
+
+    virtual lldb::ConnectionStatus Connect(const char *s, Error *error_ptr);
+
+    virtual lldb::ConnectionStatus Disconnect(Error *error_ptr);
+
+    virtual size_t Read(void *dst, size_t dst_len, uint32_t timeout_usec, lldb::ConnectionStatus &status, Error *error_ptr);
+
+    virtual size_t Write(const void *src, size_t src_len, lldb::ConnectionStatus &status, Error *error_ptr);
+
+    lldb::ConnectionStatus BytesAvailable(uint32_t timeout_usec, Error *error_ptr);
+
+    bool InterruptRead();
+
+    lldb::IOObjectSP
+    GetReadObject()
+    {
+        return m_read_sp;
+    }
+    const lldb::IOObjectSP
+    GetReadObject() const
+    {
+        return m_read_sp;
+    }
+
+    uint16_t GetListeningPort(uint32_t timeout_sec);
+
+  protected:
+    void OpenCommandPipe();
+
+    void CloseCommandPipe();
+
+    lldb::ConnectionStatus SocketListen(const char *host_and_port, Error *error_ptr);
+
+    lldb::ConnectionStatus ConnectTCP(const char *host_and_port, Error *error_ptr);
+
+    lldb::ConnectionStatus ConnectUDP(const char *args, Error *error_ptr);
+
+    lldb::ConnectionStatus NamedSocketConnect(const char *socket_name, Error *error_ptr);
+
+    lldb::ConnectionStatus NamedSocketAccept(const char *socket_name, Error *error_ptr);
+
+    lldb::IOObjectSP m_read_sp;
+    lldb::IOObjectSP m_write_sp;
+
+    Predicate<uint16_t> m_port_predicate; // Used when binding to port zero to wait for the thread
+                                          // that creates the socket, binds and listens to resolve
+                                          // the port number.
+
+    Pipe m_pipe;
+    Mutex m_mutex;
+    std::atomic<bool> m_shutting_down; // This marks that we are shutting down so if we get woken up from
+                                       // BytesAvailable to disconnect, we won't try to read again.
+    bool m_waiting_for_accept;
+
+  private:
+    DISALLOW_COPY_AND_ASSIGN(ConnectionFileDescriptor);
+};
+
+} // namespace lldb_private
+
+#endif // liblldb_ConnectionFileDescriptor_h_

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         26BC7E6910F1B85900F91463 /* Address.cpp */,
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-        26BC7E7010F1B85900F91463 /* ConnectionFileDescriptor.cpp */,
+        3F6A92D719DB4343005F2E60 /* ConnectionFileDescriptor.h */,
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         2671A0CF13482601003A87BB /* ConnectionMachPort.cpp */,
         266603CC1345B5C0004DA8B6 /* ConnectionSharedMemory.h */,

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+      );
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+      sourceTree = "<group>";
+    };
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       isa = PBXGroup;
       children = (

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         26A7A035135E6E4200FB369E /* OptionValue.cpp in Sources */,
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         9A22A163135E30370024DDC3 /* EmulationStateARM.cpp in Sources */,
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source/Core/CMakeLists.txt

 set(LLVM_NO_RTTI 1)
 
-add_lldb_library(lldbCore
+macro(add_core_subdirectory group)
+  list(APPEND CORE_SOURCES ${ARGN})
+  source_group(${group} FILES ${ARGN})
+endmacro()
+
+list(APPEND CORE_SOURCES
   Address.cpp
   AddressRange.cpp
   AddressResolver.cpp

   Broadcaster.cpp
   Communication.cpp
   Connection.cpp
-  ConnectionFileDescriptor.cpp
   ConnectionMachPort.cpp
   ConnectionSharedMemory.cpp
   ConstString.cpp

   VMRange.cpp
   )
 
+add_core_subdirectory(posix
+  posix/ConnectionFileDescriptorPosix.cpp
+  )
+  
+add_lldb_library(lldbCore ${CORE_SOURCES})
 No newline at end of file

source/Core/ConnectionFileDescriptor.cpp

-//===-- ConnectionFileDescriptor.cpp ----------------------------*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#if defined(__APPLE__)
-// Enable this special support for Apple builds where we can have unlimited
-// select bounds. We tried switching to poll() and kqueue and we were panicing
-// the kernel, so we have to stick with select for now.
-#define _DARWIN_UNLIMITED_SELECT
-#endif
-
-#include "lldb/Core/ConnectionFileDescriptor.h"
-#include "lldb/Host/Config.h"
-#include "lldb/Host/IOObject.h"
-#include "lldb/Host/SocketAddress.h"
-#include "lldb/Host/Socket.h"
-
-// C Includes
-#include <errno.h>
-#include <fcntl.h>
-#include <string.h>
-#include <stdlib.h>
-#include <sys/types.h>
-
-#ifndef LLDB_DISABLE_POSIX
-#include <termios.h>
-#endif
-
-// C++ Includes
-// Other libraries and framework includes
-#include "llvm/Support/ErrorHandling.h"
-#if defined(__APPLE__)
-#include "llvm/ADT/SmallVector.h"
-#endif
-// Project includes
-#include "lldb/lldb-private-log.h"
-#include "lldb/Core/Communication.h"
-#include "lldb/Core/Log.h"
-#include "lldb/Core/Timer.h"
-#include "lldb/Host/Host.h"
-#include "lldb/Host/Socket.h"
-#include "lldb/Interpreter/Args.h"
-
-
-using namespace lldb;
-using namespace lldb_private;
-
-ConnectionFileDescriptor::ConnectionFileDescriptor () :
-    Connection(),
-    m_pipe (),
-    m_mutex (Mutex::eMutexTypeRecursive),
-    m_shutting_down (false),
-    m_waiting_for_accept (false)
-{
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION |  LIBLLDB_LOG_OBJECT));
-    if (log)
-        log->Printf ("%p ConnectionFileDescriptor::ConnectionFileDescriptor ()",
-                     static_cast<void*>(this));
-}
-
-ConnectionFileDescriptor::ConnectionFileDescriptor (int fd, bool owns_fd) :
-    Connection(),
-    m_pipe (),
-    m_mutex (Mutex::eMutexTypeRecursive),
-    m_shutting_down (false),
-    m_waiting_for_accept (false)
-{
-    m_write_sp.reset(new File(fd, owns_fd));
-    m_read_sp.reset(new File(fd, false));
-
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION |  LIBLLDB_LOG_OBJECT));
-    if (log)
-        log->Printf ("%p ConnectionFileDescriptor::ConnectionFileDescriptor (fd = %i, owns_fd = %i)",
-                     static_cast<void*>(this), fd, owns_fd);
-    OpenCommandPipe ();
-}
-
-
-ConnectionFileDescriptor::~ConnectionFileDescriptor ()
-{
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION |  LIBLLDB_LOG_OBJECT));
-    if (log)
-        log->Printf ("%p ConnectionFileDescriptor::~ConnectionFileDescriptor ()",
-                     static_cast<void*>(this));
-    Disconnect (NULL);
-    CloseCommandPipe ();
-}
-
-void
-ConnectionFileDescriptor::OpenCommandPipe ()
-{
-    CloseCommandPipe();
-
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION));
-    // Make the command file descriptor here:
-    if (!m_pipe.Open())
-    {
-        if (log)
-            log->Printf ("%p ConnectionFileDescriptor::OpenCommandPipe () - could not make pipe: %s",
-                         static_cast<void*>(this), strerror(errno));
-    }
-    else
-    {
-        if (log)
-            log->Printf ("%p ConnectionFileDescriptor::OpenCommandPipe() - success readfd=%d writefd=%d",
-                         static_cast<void*>(this),
-                         m_pipe.GetReadFileDescriptor(),
-                         m_pipe.GetWriteFileDescriptor());
-    }
-}
-
-void
-ConnectionFileDescriptor::CloseCommandPipe ()
-{
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION));
-    if (log)
-        log->Printf ("%p ConnectionFileDescriptor::CloseCommandPipe()",
-                     static_cast<void*>(this));
-
-    m_pipe.Close();
-}
-
-bool
-ConnectionFileDescriptor::IsConnected () const
-{
-    return (m_read_sp && m_read_sp->IsValid()) || (m_write_sp && m_write_sp->IsValid());
-}
-
-ConnectionStatus
-ConnectionFileDescriptor::Connect (const char *s, Error *error_ptr)
-{
-    Mutex::Locker locker (m_mutex);
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION));
-    if (log)
-        log->Printf ("%p ConnectionFileDescriptor::Connect (url = '%s')",
-                     static_cast<void*>(this), s);
-
-    OpenCommandPipe();
-
-    if (s && s[0])
-    {
-        if (strstr(s, "listen://") == s)
-        {
-            // listen://HOST:PORT
-            return SocketListen (s + strlen("listen://"), error_ptr);
-        }
-        else if (strstr(s, "accept://") == s)
-        {
-            // unix://SOCKNAME
-            return NamedSocketAccept (s + strlen("accept://"), error_ptr);
-        }
-        else if (strstr(s, "unix-accept://") == s)
-        {
-            // unix://SOCKNAME
-            return NamedSocketAccept (s + strlen("unix-accept://"), error_ptr);
-        }
-        else if (strstr(s, "connect://") == s)
-        {
-            return ConnectTCP (s + strlen("connect://"), error_ptr);
-        }
-        else if (strstr(s, "tcp-connect://") == s)
-        {
-            return ConnectTCP (s + strlen("tcp-connect://"), error_ptr);
-        }
-        else if (strstr(s, "udp://") == s)
-        {
-            return ConnectUDP (s + strlen("udp://"), error_ptr);
-        }
-#ifndef LLDB_DISABLE_POSIX
-        else if (strstr(s, "fd://") == s)
-        {
-            // Just passing a native file descriptor within this current process
-            // that is already opened (possibly from a service or other source).
-            s += strlen ("fd://");
-            bool success = false;
-            int fd = Args::StringToSInt32 (s, -1, 0, &success);
-
-            if (success)
-            {
-                // We have what looks to be a valid file descriptor, but we 
-                // should make sure it is. We currently are doing this by trying to
-                // get the flags from the file descriptor and making sure it 
-                // isn't a bad fd.
-                errno = 0;
-                int flags = ::fcntl (fd, F_GETFL, 0);
-                if (flags == -1 || errno == EBADF)
-                {
-                    if (error_ptr)
-                        error_ptr->SetErrorStringWithFormat ("stale file descriptor: %s", s);
-                    m_read_sp.reset();
-                    m_write_sp.reset();
-                    return eConnectionStatusError;
-                }
-                else
-                {
-                    // Don't take ownership of a file descriptor that gets passed
-                    // to us since someone else opened the file descriptor and
-                    // handed it to us. 
-                    // TODO: Since are using a URL to open connection we should 
-                    // eventually parse options using the web standard where we
-                    // have "fd://123?opt1=value;opt2=value" and we can have an
-                    // option be "owns=1" or "owns=0" or something like this to
-                    // allow us to specify this. For now, we assume we must 
-                    // assume we don't own it.
-
-                    std::unique_ptr<Socket> tcp_socket;
-                    tcp_socket.reset(new Socket(fd, Socket::ProtocolTcp, false));
-                    // Try and get a socket option from this file descriptor to 
-                    // see if this is a socket and set m_is_socket accordingly.
-                    int resuse;
-                    bool is_socket = !!tcp_socket->GetOption(SOL_SOCKET, SO_REUSEADDR, resuse);
-                    if (is_socket)
-                    {
-                        m_read_sp = std::move(tcp_socket);
-                        m_write_sp = m_read_sp;
-                    }
-                    else
-                    {
-                        m_read_sp.reset(new File(fd, false));
-                        m_write_sp.reset(new File(fd, false));
-                    }
-                    return eConnectionStatusSuccess;
-                }
-            }
-
-            if (error_ptr)
-                error_ptr->SetErrorStringWithFormat ("invalid file descriptor: \"fd://%s\"", s);
-            m_read_sp.reset();
-            m_write_sp.reset();
-            return eConnectionStatusError;
-        }
-        else if (strstr(s, "file://") == s)
-        {
-            // file:///PATH
-            const char *path = s + strlen("file://");
-            int fd = -1;
-            do
-            {
-                fd = ::open (path, O_RDWR);
-            } while (fd == -1 && errno == EINTR);
-
-            if (fd == -1)
-            {
-                if (error_ptr)
-                    error_ptr->SetErrorToErrno();
-                return eConnectionStatusError;
-            }
-
-            if (::isatty(fd))
-            {
-                // Set up serial terminal emulation
-                struct termios options;
-                ::tcgetattr (fd, &options);
-
-                // Set port speed to maximum
-                ::cfsetospeed (&options, B115200);
-                ::cfsetispeed (&options, B115200);
-
-                // Raw input, disable echo and signals
-                options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
-
-                // Make sure only one character is needed to return from a read
-                options.c_cc[VMIN]  = 1;
-                options.c_cc[VTIME] = 0;
-
-                ::tcsetattr (fd, TCSANOW, &options);
-            }
-
-            int flags = ::fcntl (fd, F_GETFL, 0);
-            if (flags >= 0)
-            {
-                if ((flags & O_NONBLOCK) == 0)
-                {
-                    flags |= O_NONBLOCK;
-                    ::fcntl (fd, F_SETFL, flags);
-                }
-            }
-            m_read_sp.reset(new File(fd, true));
-            m_write_sp.reset(new File(fd, false));
-            return eConnectionStatusSuccess;
-        }
-#endif
-        if (error_ptr)
-            error_ptr->SetErrorStringWithFormat ("unsupported connection URL: '%s'", s);
-        return eConnectionStatusError;
-    }
-    if (error_ptr)
-        error_ptr->SetErrorString("invalid connect arguments");
-    return eConnectionStatusError;
-}
-
-bool
-ConnectionFileDescriptor::InterruptRead()
-{
-    return m_pipe.Write("i", 1) == 1;
-}
-
-ConnectionStatus
-ConnectionFileDescriptor::Disconnect (Error *error_ptr)
-{
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION));
-    if (log)
-        log->Printf ("%p ConnectionFileDescriptor::Disconnect ()",
-                     static_cast<void*>(this));
-
-    ConnectionStatus status = eConnectionStatusSuccess;
-
-    if (!IsConnected())
-    {
-        if (log)
-            log->Printf ("%p ConnectionFileDescriptor::Disconnect(): Nothing to disconnect",
-                         static_cast<void*>(this));
-        return eConnectionStatusSuccess;
-    }
-
-    if (m_read_sp && m_read_sp->IsValid() && m_read_sp->GetFdType() == IOObject::eFDTypeSocket)
-        static_cast<Socket&>(*m_read_sp).PreDisconnect();
-
-    // Try to get the ConnectionFileDescriptor's mutex.  If we fail, that is quite likely
-    // because somebody is doing a blocking read on our file descriptor.  If that's the case,
-    // then send the "q" char to the command file channel so the read will wake up and the connection
-    // will then know to shut down.
-
-    m_shutting_down = true;
-
-    Mutex::Locker locker;
-    bool got_lock = locker.TryLock (m_mutex);
-
-    if (!got_lock)
-    {
-        if (m_pipe.WriteDescriptorIsValid())
-        {
-            int result;
-            result = m_pipe.Write("q", 1) == 1;
-            if (log)
-                log->Printf ("%p ConnectionFileDescriptor::Disconnect(): Couldn't get the lock, sent 'q' to %d, result = %d.",
-                             static_cast<void*>(this), m_pipe.GetWriteFileDescriptor(), result);
-        }
-        else if (log)
-        {
-            log->Printf ("%p ConnectionFileDescriptor::Disconnect(): Couldn't get the lock, but no command pipe is available.",
-                         static_cast<void*>(this));
-        }
-        locker.Lock (m_mutex);
-    }
-
-    Error error = m_read_sp->Close();
-    Error error2 = m_write_sp->Close();
-    if (error.Fail() || error2.Fail())
-        status = eConnectionStatusError;
-    if (error_ptr)
-        *error_ptr = error.Fail() ? error : error2;
-
-    m_shutting_down = false;
-    return status;
-}
-
-size_t
-ConnectionFileDescriptor::Read (void *dst, 
-                                size_t dst_len, 
-                                uint32_t timeout_usec,
-                                ConnectionStatus &status, 
-                                Error *error_ptr)
-{
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION));
-
-    Mutex::Locker locker;
-    bool got_lock = locker.TryLock (m_mutex);
-    if (!got_lock)
-    {
-        if (log)
-            log->Printf ("%p ConnectionFileDescriptor::Read () failed to get the connection lock.",
-                         static_cast<void*>(this));
-        if (error_ptr)
-            error_ptr->SetErrorString ("failed to get the connection lock for read.");
-
-        status = eConnectionStatusTimedOut;
-        return 0;
-    }
-    else if (m_shutting_down)
-        return eConnectionStatusError;
-
-    status = BytesAvailable (timeout_usec, error_ptr);
-    if (status != eConnectionStatusSuccess)
-        return 0;
-
-    Error error;
-    size_t bytes_read = dst_len;
-    error = m_read_sp->Read(dst, bytes_read);
-
-    if (log)
-    {
-        log->Printf("%p ConnectionFileDescriptor::Read()  fd = %" PRIu64 ", dst = %p, dst_len = %" PRIu64 ") => %" PRIu64 ", error = %s",
-                    static_cast<void*>(this),
-                    static_cast<uint64_t>(m_read_sp->GetWaitableHandle()),
-                    static_cast<void*>(dst),
-                    static_cast<uint64_t>(dst_len),
-                    static_cast<uint64_t>(bytes_read),
-                    error.AsCString());
-    }
-
-    if (bytes_read == 0)
-    {
-        error.Clear(); // End-of-file.  Do not automatically close; pass along for the end-of-file handlers.
-        status = eConnectionStatusEndOfFile;
-    }
-
-    if (error_ptr)
-        *error_ptr = error;
-
-    if (error.Fail())
-    {
-        uint32_t error_value = error.GetError();
-        switch (error_value)
-        {
-        case EAGAIN:    // The file was marked for non-blocking I/O, and no data were ready to be read.
-            if (m_read_sp->GetFdType() == IOObject::eFDTypeSocket)
-                status = eConnectionStatusTimedOut;
-            else
-                status = eConnectionStatusSuccess;
-            return 0;
-
-        case EFAULT:    // Buf points outside the allocated address space.
-        case EINTR:     // A read from a slow device was interrupted before any data arrived by the delivery of a signal.
-        case EINVAL:    // The pointer associated with fildes was negative.
-        case EIO:       // An I/O error occurred while reading from the file system.
-                        // The process group is orphaned.
-                        // The file is a regular file, nbyte is greater than 0,
-                        // the starting position is before the end-of-file, and
-                        // the starting position is greater than or equal to the
-                        // offset maximum established for the open file
-                        // descriptor associated with fildes.
-        case EISDIR:    // An attempt is made to read a directory.
-        case ENOBUFS:   // An attempt to allocate a memory buffer fails.
-        case ENOMEM:    // Insufficient memory is available.
-            status = eConnectionStatusError;
-            break;  // Break to close....
-
-        case ENOENT:    // no such file or directory
-        case EBADF:     // fildes is not a valid file or socket descriptor open for reading.
-        case ENXIO:     // An action is requested of a device that does not exist..
-                        // A requested action cannot be performed by the device.
-        case ECONNRESET:// The connection is closed by the peer during a read attempt on a socket.
-        case ENOTCONN:  // A read is attempted on an unconnected socket.
-            status = eConnectionStatusLostConnection;
-            break;  // Break to close....
-
-        case ETIMEDOUT: // A transmission timeout occurs during a read attempt on a socket.
-            status = eConnectionStatusTimedOut;
-            return 0;
-
-        default:
-            if (log)
-                log->Printf("%p ConnectionFileDescriptor::Read (), unexpected error: %s",
-                            static_cast<void*>(this), strerror(error_value));
-            status = eConnectionStatusError;
-            break;  // Break to close....
-
-        }
-
-        return 0;
-    }
-    return bytes_read;
-}
-
-size_t
-ConnectionFileDescriptor::Write (const void *src, size_t src_len, ConnectionStatus &status, Error *error_ptr)
-{
-    Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION));
-    if (log)
-        log->Printf ("%p ConnectionFileDescriptor::Write (src = %p, src_len = %" PRIu64 ")",
-                     static_cast<void*>(this), static_cast<const void*>(src),
-                     static_cast<uint64_t>(src_len));
-
-    if (!IsConnected ())
-    {
-        if (error_ptr)
-            error_ptr->SetErrorString("not connected");
-        status = eConnectionStatusNoConnection;
-        return 0;
-    }
-
-
-    Error error;
-
-    size_t bytes_sent = src_len;
-    error = m_write_sp->Write(src, bytes_sent);
-
-    if (log)
-    {
-        log->Printf ("%p ConnectionFileDescriptor::Write(fd = %" PRIu64 ", src = %p, src_len = %" PRIu64 ") => %" PRIu64 " (error = %s)",
-                     static_cast<void*>(this),
-                     static_cast<uint64_t>(m_write_sp->GetWaitableHandle()),
-                     static_cast<const void*>(src),
-                     static_cast<uint64_t>(src_len),
-                     static_cast<uint64_t>(bytes_sent),
-                     error.AsCString());
-    }
-
-    if (error_ptr)
-        *error_ptr = error;
-
-    if (error.Fail())
-    {
-        switch (error.GetError())
-        {
-        case EAGAIN:
-        case EINTR:
-            status = eConnectionStatusSuccess;
-            return 0;
-
-        case ECONNRESET:// The connection is closed by the peer during a read attempt on a socket.
-        case ENOTCONN:  // A read is attempted on an unconnected socket.
-            status = eConnectionStatusLostConnection;
-            break;  // Break to close....
-
-        default:
-            status = eConnectionStatusError;
-            break;  // Break to close....
-        }
-
-        return 0;
-    }
-
-    status = eConnectionStatusSuccess;
-    return bytes_sent;
-}
-
-
-
-// This ConnectionFileDescriptor::BytesAvailable() uses select().
-//
-// PROS:
-//  - select is consistent across most unix platforms
-//  - The Apple specific version allows for unlimited fds in the fd_sets by
-//    setting the _DARWIN_UNLIMITED_SELECT define prior to including the
-//    required header files.
-// CONS:
-//  - on non-Apple platforms, only supports file descriptors up to FD_SETSIZE.
-//     This implementation  will assert if it runs into that hard limit to let
-//     users know that another ConnectionFileDescriptor::BytesAvailable() should
-//     be used or a new version of ConnectionFileDescriptor::BytesAvailable()
-//     should be written for the system that is running into the limitations.
-
-#if defined(__APPLE__)
-#define FD_SET_DATA(fds) fds.data()
-#else
-#define FD_SET_DATA(fds) &fds
-#endif
-
-ConnectionStatus
-ConnectionFileDescriptor::BytesAvailable (uint32_t timeout_usec, Error *error_ptr)
-{
-    // Don't need to take the mutex here separately since we are only called from Read.  If we
-    // ever get used more generally we will need to lock here as well.
-
-    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_CONNECTION));
-    if (log)
-        log->Printf("%p ConnectionFileDescriptor::BytesAvailable (timeout_usec = %u)",
-                    static_cast<void*>(this), timeout_usec);
-
-    struct timeval *tv_ptr;
-    struct timeval tv;
-    if (timeout_usec == UINT32_MAX)
-    {
-        // Inifinite wait...
-        tv_ptr = nullptr;
-    }
-    else
-    {
-        TimeValue time_value;
-        time_value.OffsetWithMicroSeconds (timeout_usec);
-        tv.tv_sec = time_value.seconds();
-        tv.tv_usec = time_value.microseconds();
-        tv_ptr = &tv;
-    }
-
-    // Make a copy of the file descriptors to make sure we don't
-    // have another thread change these values out from under us
-    // and cause problems in the loop below where like in FS_SET()
-    const IOObject::WaitableHandle handle = m_read_sp->GetWaitableHandle();
-    const int pipe_fd = m_pipe.GetReadFileDescriptor();
-
-    if (handle != IOObject::kInvalidHandleValue)
-    {
-#if defined(_MSC_VER)
-        // select() won't accept pipes on Windows.  The entire Windows codepath needs to be
-        // converted over to using WaitForMultipleObjects and event HANDLEs, but for now at least
-        // this will allow ::select() to not return an error.
-        const bool have_pipe_fd = false;
-#else
-        const bool have_pipe_fd = pipe_fd >= 0;
-#if !defined(__APPLE__)
-        assert (handle < FD_SETSIZE);
-        if (have_pipe_fd)
-            assert (pipe_fd < FD_SETSIZE);
-#endif
-#endif
-        while (handle == m_read_sp->GetWaitableHandle())
-        {
-            const int nfds = std::max<int>(handle, pipe_fd) + 1;
-#if defined(__APPLE__)
-            llvm::SmallVector<fd_set, 1> read_fds;
-            read_fds.resize((nfds/FD_SETSIZE) + 1);
-            for (size_t i=0; i<read_fds.size(); ++i)
-                FD_ZERO (&read_fds[i]);
-            // FD_SET doesn't bounds check, it just happily walks off the end
-            // but we have taken care of making the extra storage with our
-            // SmallVector of fd_set objects
-#else
-            fd_set read_fds;
-            FD_ZERO (&read_fds);
-#endif
-            FD_SET (handle, FD_SET_DATA(read_fds));
-            if (have_pipe_fd)
-                FD_SET (pipe_fd, FD_SET_DATA(read_fds));
-
-            Error error;
-
-            if (log)
-            {
-                if (have_pipe_fd)
-                    log->Printf("%p ConnectionFileDescriptor::BytesAvailable()  ::select (nfds=%i, fds={%i, %i}, NULL, NULL, timeout=%p)...",
-                                static_cast<void*>(this), nfds, handle, pipe_fd,
-                                static_cast<void*>(tv_ptr));
-                else
-                    log->Printf("%p ConnectionFileDescriptor::BytesAvailable()  ::select (nfds=%i, fds={%i}, NULL, NULL, timeout=%p)...",
-                                static_cast<void*>(this), nfds, handle,
-                                static_cast<void*>(tv_ptr));
-            }
-
-            const int num_set_fds = ::select (nfds, FD_SET_DATA(read_fds), NULL, NULL, tv_ptr);
-            if (num_set_fds < 0)
-                error.SetErrorToErrno();
-            else
-                error.Clear();
-
-            if (log)
-            {
-                if (have_pipe_fd)
-                    log->Printf("%p ConnectionFileDescriptor::BytesAvailable()  ::select (nfds=%i, fds={%i, %i}, NULL, NULL, timeout=%p) => %d, error = %s",
-                                static_cast<void*>(this), nfds, handle,
-                                pipe_fd, static_cast<void*>(tv_ptr), num_set_fds,
-                                error.AsCString());
-                else
-                    log->Printf("%p ConnectionFileDescriptor::BytesAvailable()  ::select (nfds=%i, fds={%i}, NULL, NULL, timeout=%p) => %d, error = %s",
-                                static_cast<void*>(this), nfds, handle,
-                                static_cast<void*>(tv_ptr), num_set_fds,
-                                error.AsCString());
-            }
-
-            if (error_ptr)
-                *error_ptr = error;
-
-            if (error.Fail())
-            {
-                switch (error.GetError())
-                {
-                    case EBADF:     // One of the descriptor sets specified an invalid descriptor.
-                        return eConnectionStatusLostConnection;
-
-                    case EINVAL:    // The specified time limit is invalid. One of its components is negative or too large.
-                    default:        // Other unknown error
-                        return eConnectionStatusError;
-
-                    case EAGAIN:    // The kernel was (perhaps temporarily) unable to
-                        // allocate the requested number of file descriptors,
-                        // or we have non-blocking IO
-                    case EINTR:     // A signal was delivered before the time limit
-                        // expired and before any of the selected events
-                        // occurred.
-                        break;      // Lets keep reading to until we timeout
-                }
-            }
-            else if (num_set_fds == 0)
-            {
-                return eConnectionStatusTimedOut;
-            }
-            else if (num_set_fds > 0)
-            {
-                if (FD_ISSET(handle, FD_SET_DATA(read_fds)))
-                    return eConnectionStatusSuccess;
-                if (have_pipe_fd && FD_ISSET(pipe_fd, FD_SET_DATA(read_fds)))
-                {
-                    // We got a command to exit.  Read the data from that pipe:
-                    char buffer[16];
-                    ssize_t bytes_read;
-
-                    do
-                    {
-                        bytes_read = ::read (pipe_fd, buffer, sizeof(buffer));
-                    } while (bytes_read < 0 && errno == EINTR);
-                    
-                    switch (buffer[0])
-                    {
-                    case 'q':
-                        if (log)
-                            log->Printf("%p ConnectionFileDescriptor::BytesAvailable() got data: %*s from the command channel.",
-                                        static_cast<void*>(this),
-                                        static_cast<int>(bytes_read), buffer);
-                        return eConnectionStatusEndOfFile;
-                    case 'i':
-                        // Interrupt the current read
-                        return eConnectionStatusInterrupted;
-                    }
-                }
-            }
-        }
-    }
-
-    if (error_ptr)
-        error_ptr->SetErrorString("not connected");
-    return eConnectionStatusLostConnection;
-}
-
-ConnectionStatus
-ConnectionFileDescriptor::NamedSocketAccept (const char *socket_name, Error *error_ptr)
-{
-    Socket* socket = nullptr;
-    Error error = Socket::UnixDomainAccept(socket_name, socket);
-    if (error_ptr)
-        *error_ptr = error;
-    m_write_sp.reset(socket);
-    m_read_sp = m_write_sp;
-    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
-}
-
-ConnectionStatus
-ConnectionFileDescriptor::NamedSocketConnect (const char *socket_name, Error *error_ptr)
-{
-    Socket* socket = nullptr;
-    Error error = Socket::UnixDomainConnect(socket_name, socket);
-    if (error_ptr)
-        *error_ptr = error;
-    m_write_sp.reset(socket);
-    m_read_sp = m_write_sp;
-    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
-}
-
-ConnectionStatus
-ConnectionFileDescriptor::SocketListen(const char *s, Error *error_ptr)
-{
-    m_port_predicate.SetValue(0, eBroadcastNever);
-
-    Socket* socket = nullptr;
-    m_waiting_for_accept = true;
-    Error error = Socket::TcpListen(s, socket, &m_port_predicate);
-    if (error_ptr)
-        *error_ptr = error;
-    if (error.Fail())
-        return eConnectionStatusError;
-
-    std::unique_ptr<Socket> listening_socket_up;
-
-    listening_socket_up.reset(socket);
-    socket = nullptr;
-    error = listening_socket_up->BlockingAccept(s, socket);
-    listening_socket_up.reset();
-    if (error_ptr)
-        *error_ptr = error;
-    if (error.Fail())
-        return eConnectionStatusError;
-
-    m_write_sp.reset(socket);
-    m_read_sp = m_write_sp;
-    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
-}
-
-ConnectionStatus
-ConnectionFileDescriptor::ConnectTCP(const char *s, Error *error_ptr)
-{
-    Socket* socket = nullptr;
-    Error error = Socket::TcpConnect(s, socket);
-    if (error_ptr)
-        *error_ptr = error;
-    m_write_sp.reset(socket);
-    m_read_sp = m_write_sp;
-    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
-}
-
-ConnectionStatus
-ConnectionFileDescriptor::ConnectUDP(const char *s, Error *error_ptr)
-{
-    Socket* send_socket = nullptr;
-    Socket* recv_socket = nullptr;
-    Error error = Socket::UdpConnect(s, send_socket, recv_socket);
-    if (error_ptr)
-        *error_ptr = error;
-    m_write_sp.reset(send_socket);
-    m_read_sp.reset(recv_socket);
-    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
-}
-
-
-uint16_t ConnectionFileDescriptor::GetListeningPort(uint32_t timeout_sec)
-{
-    uint16_t bound_port = 0;
-    if (timeout_sec == UINT32_MAX)
-        m_port_predicate.WaitForValueNotEqualTo (0, bound_port);
-    else
-    {
-        TimeValue timeout = TimeValue::Now();
-        timeout.OffsetWithSeconds(timeout_sec);
-        m_port_predicate.WaitForValueNotEqualTo (0, bound_port, &timeout);
-    }
-    return bound_port;
-}

source/Core/posix/ConnectionFileDescriptorPosix.cpp

+//===-- ConnectionFileDescriptorPosix.cpp -----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__APPLE__)
+// Enable this special support for Apple builds where we can have unlimited
+// select bounds. We tried switching to poll() and kqueue and we were panicing
+// the kernel, so we have to stick with select for now.
+#define _DARWIN_UNLIMITED_SELECT
+#endif
+
+#include "lldb/Core/posix/ConnectionFileDescriptorPosix.h"
+#include "lldb/Host/Config.h"
+#include "lldb/Host/IOObject.h"
+#include "lldb/Host/SocketAddress.h"
+#include "lldb/Host/Socket.h"
+
+// C Includes
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/types.h>
+
+#ifndef LLDB_DISABLE_POSIX
+#include <termios.h>
+#endif
+
+// C++ Includes
+// Other libraries and framework includes
+#include "llvm/Support/ErrorHandling.h"
+#if defined(__APPLE__)
+#include "llvm/ADT/SmallVector.h"
+#endif
+// Project includes
+#include "lldb/lldb-private-log.h"
+#include "lldb/Core/Communication.h"
+#include "lldb/Core/Log.h"
+#include "lldb/Core/Timer.h"
+#include "lldb/Host/Host.h"
+#include "lldb/Host/Socket.h"
+#include "lldb/Interpreter/Args.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+ConnectionFileDescriptor::ConnectionFileDescriptor()
+    : Connection()
+    , m_pipe()
+    , m_mutex(Mutex::eMutexTypeRecursive)
+    , m_shutting_down(false)
+    , m_waiting_for_accept(false)
+{
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION | LIBLLDB_LOG_OBJECT));
+    if (log)
+        log->Printf("%p ConnectionFileDescriptor::ConnectionFileDescriptor ()", static_cast<void *>(this));
+}
+
+ConnectionFileDescriptor::ConnectionFileDescriptor(int fd, bool owns_fd)
+    : Connection()
+    , m_pipe()
+    , m_mutex(Mutex::eMutexTypeRecursive)
+    , m_shutting_down(false)
+    , m_waiting_for_accept(false)
+{
+    m_write_sp.reset(new File(fd, owns_fd));
+    m_read_sp.reset(new File(fd, false));
+
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION | LIBLLDB_LOG_OBJECT));
+    if (log)
+        log->Printf("%p ConnectionFileDescriptor::ConnectionFileDescriptor (fd = %i, owns_fd = %i)", static_cast<void *>(this), fd,
+                    owns_fd);
+    OpenCommandPipe();
+}
+
+ConnectionFileDescriptor::~ConnectionFileDescriptor()
+{
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION | LIBLLDB_LOG_OBJECT));
+    if (log)
+        log->Printf("%p ConnectionFileDescriptor::~ConnectionFileDescriptor ()", static_cast<void *>(this));
+    Disconnect(NULL);
+    CloseCommandPipe();
+}
+
+void
+ConnectionFileDescriptor::OpenCommandPipe()
+{
+    CloseCommandPipe();
+
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
+    // Make the command file descriptor here:
+    if (!m_pipe.Open())
+    {
+        if (log)
+            log->Printf("%p ConnectionFileDescriptor::OpenCommandPipe () - could not make pipe: %s", static_cast<void *>(this),
+                        strerror(errno));
+    }
+    else
+    {
+        if (log)
+            log->Printf("%p ConnectionFileDescriptor::OpenCommandPipe() - success readfd=%d writefd=%d", static_cast<void *>(this),
+                        m_pipe.GetReadFileDescriptor(), m_pipe.GetWriteFileDescriptor());
+    }
+}
+
+void
+ConnectionFileDescriptor::CloseCommandPipe()
+{
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
+    if (log)
+        log->Printf("%p ConnectionFileDescriptor::CloseCommandPipe()", static_cast<void *>(this));
+
+    m_pipe.Close();
+}
+
+bool
+ConnectionFileDescriptor::IsConnected() const
+{
+    return (m_read_sp && m_read_sp->IsValid()) || (m_write_sp && m_write_sp->IsValid());
+}
+
+ConnectionStatus
+ConnectionFileDescriptor::Connect(const char *s, Error *error_ptr)
+{
+    Mutex::Locker locker(m_mutex);
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
+    if (log)
+        log->Printf("%p ConnectionFileDescriptor::Connect (url = '%s')", static_cast<void *>(this), s);
+
+    OpenCommandPipe();
+
+    if (s && s[0])
+    {
+        if (strstr(s, "listen://") == s)
+        {
+            // listen://HOST:PORT
+            return SocketListen(s + strlen("listen://"), error_ptr);
+        }
+        else if (strstr(s, "accept://") == s)
+        {
+            // unix://SOCKNAME
+            return NamedSocketAccept(s + strlen("accept://"), error_ptr);
+        }
+        else if (strstr(s, "unix-accept://") == s)
+        {
+            // unix://SOCKNAME
+            return NamedSocketAccept(s + strlen("unix-accept://"), error_ptr);
+        }
+        else if (strstr(s, "connect://") == s)
+        {
+            return ConnectTCP(s + strlen("connect://"), error_ptr);
+        }
+        else if (strstr(s, "tcp-connect://") == s)
+        {
+            return ConnectTCP(s + strlen("tcp-connect://"), error_ptr);
+        }
+        else if (strstr(s, "udp://") == s)
+        {
+            return ConnectUDP(s + strlen("udp://"), error_ptr);
+        }
+#ifndef LLDB_DISABLE_POSIX
+        else if (strstr(s, "fd://") == s)
+        {
+            // Just passing a native file descriptor within this current process
+            // that is already opened (possibly from a service or other source).
+            s += strlen("fd://");
+            bool success = false;
+            int fd = Args::StringToSInt32(s, -1, 0, &success);
+
+            if (success)
+            {
+                // We have what looks to be a valid file descriptor, but we
+                // should make sure it is. We currently are doing this by trying to
+                // get the flags from the file descriptor and making sure it
+                // isn't a bad fd.
+                errno = 0;
+                int flags = ::fcntl(fd, F_GETFL, 0);
+                if (flags == -1 || errno == EBADF)
+                {
+                    if (error_ptr)
+                        error_ptr->SetErrorStringWithFormat("stale file descriptor: %s", s);
+                    m_read_sp.reset();
+                    m_write_sp.reset();
+                    return eConnectionStatusError;
+                }
+                else
+                {
+                    // Don't take ownership of a file descriptor that gets passed
+                    // to us since someone else opened the file descriptor and
+                    // handed it to us.
+                    // TODO: Since are using a URL to open connection we should
+                    // eventually parse options using the web standard where we
+                    // have "fd://123?opt1=value;opt2=value" and we can have an
+                    // option be "owns=1" or "owns=0" or something like this to
+                    // allow us to specify this. For now, we assume we must
+                    // assume we don't own it.
+
+                    std::unique_ptr<Socket> tcp_socket;
+                    tcp_socket.reset(new Socket(fd, Socket::ProtocolTcp, false));
+                    // Try and get a socket option from this file descriptor to
+                    // see if this is a socket and set m_is_socket accordingly.
+                    int resuse;
+                    bool is_socket = !!tcp_socket->GetOption(SOL_SOCKET, SO_REUSEADDR, resuse);
+                    if (is_socket)
+                    {
+                        m_read_sp = std::move(tcp_socket);
+                        m_write_sp = m_read_sp;
+                    }
+                    else
+                    {
+                        m_read_sp.reset(new File(fd, false));
+                        m_write_sp.reset(new File(fd, false));
+                    }
+                    return eConnectionStatusSuccess;
+                }
+            }
+
+            if (error_ptr)
+                error_ptr->SetErrorStringWithFormat("invalid file descriptor: \"fd://%s\"", s);
+            m_read_sp.reset();
+            m_write_sp.reset();
+            return eConnectionStatusError;
+        }
+        else if (strstr(s, "file://") == s)
+        {
+            // file:///PATH
+            const char *path = s + strlen("file://");
+            int fd = -1;
+            do
+            {
+                fd = ::open(path, O_RDWR);
+            } while (fd == -1 && errno == EINTR);
+
+            if (fd == -1)
+            {
+                if (error_ptr)
+                    error_ptr->SetErrorToErrno();
+                return eConnectionStatusError;
+            }
+
+            if (::isatty(fd))
+            {
+                // Set up serial terminal emulation
+                struct termios options;
+                ::tcgetattr(fd, &options);
+
+                // Set port speed to maximum
+                ::cfsetospeed(&options, B115200);
+                ::cfsetispeed(&options, B115200);
+
+                // Raw input, disable echo and signals
+                options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
+
+                // Make sure only one character is needed to return from a read
+                options.c_cc[VMIN] = 1;
+                options.c_cc[VTIME] = 0;
+
+                ::tcsetattr(fd, TCSANOW, &options);
+            }
+
+            int flags = ::fcntl(fd, F_GETFL, 0);
+            if (flags >= 0)
+            {
+                if ((flags & O_NONBLOCK) == 0)
+                {
+                    flags |= O_NONBLOCK;
+                    ::fcntl(fd, F_SETFL, flags);
+                }
+            }
+            m_read_sp.reset(new File(fd, true));
+            m_write_sp.reset(new File(fd, false));
+            return eConnectionStatusSuccess;
+        }
+#endif
+        if (error_ptr)
+            error_ptr->SetErrorStringWithFormat("unsupported connection URL: '%s'", s);
+        return eConnectionStatusError;
+    }
+    if (error_ptr)
+        error_ptr->SetErrorString("invalid connect arguments");
+    return eConnectionStatusError;
+}
+
+bool
+ConnectionFileDescriptor::InterruptRead()
+{
+    return m_pipe.Write("i", 1) == 1;
+}
+
+ConnectionStatus
+ConnectionFileDescriptor::Disconnect(Error *error_ptr)
+{
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
+    if (log)
+        log->Printf("%p ConnectionFileDescriptor::Disconnect ()", static_cast<void *>(this));
+
+    ConnectionStatus status = eConnectionStatusSuccess;
+
+    if (!IsConnected())
+    {
+        if (log)
+            log->Printf("%p ConnectionFileDescriptor::Disconnect(): Nothing to disconnect", static_cast<void *>(this));
+        return eConnectionStatusSuccess;
+    }
+
+    if (m_read_sp && m_read_sp->IsValid() && m_read_sp->GetFdType() == IOObject::eFDTypeSocket)
+        static_cast<Socket &>(*m_read_sp).PreDisconnect();
+
+    // Try to get the ConnectionFileDescriptor's mutex.  If we fail, that is quite likely
+    // because somebody is doing a blocking read on our file descriptor.  If that's the case,
+    // then send the "q" char to the command file channel so the read will wake up and the connection
+    // will then know to shut down.
+
+    m_shutting_down = true;
+
+    Mutex::Locker locker;
+    bool got_lock = locker.TryLock(m_mutex);
+
+    if (!got_lock)
+    {
+        if (m_pipe.WriteDescriptorIsValid())
+        {
+            int result;
+            result = m_pipe.Write("q", 1) == 1;
+            if (log)
+                log->Printf("%p ConnectionFileDescriptor::Disconnect(): Couldn't get the lock, sent 'q' to %d, result = %d.",
+                            static_cast<void *>(this), m_pipe.GetWriteFileDescriptor(), result);
+        }
+        else if (log)
+        {
+            log->Printf("%p ConnectionFileDescriptor::Disconnect(): Couldn't get the lock, but no command pipe is available.",
+                        static_cast<void *>(this));
+        }
+        locker.Lock(m_mutex);
+    }
+
+    Error error = m_read_sp->Close();
+    Error error2 = m_write_sp->Close();
+    if (error.Fail() || error2.Fail())
+        status = eConnectionStatusError;
+    if (error_ptr)
+        *error_ptr = error.Fail() ? error : error2;
+
+    m_shutting_down = false;
+    return status;
+}
+
+size_t
+ConnectionFileDescriptor::Read(void *dst, size_t dst_len, uint32_t timeout_usec, ConnectionStatus &status, Error *error_ptr)
+{
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
+
+    Mutex::Locker locker;
+    bool got_lock = locker.TryLock(m_mutex);
+    if (!got_lock)
+    {
+        if (log)
+            log->Printf("%p ConnectionFileDescriptor::Read () failed to get the connection lock.", static_cast<void *>(this));
+        if (error_ptr)
+            error_ptr->SetErrorString("failed to get the connection lock for read.");
+
+        status = eConnectionStatusTimedOut;
+        return 0;
+    }
+    else if (m_shutting_down)
+        return eConnectionStatusError;
+
+    status = BytesAvailable(timeout_usec, error_ptr);
+    if (status != eConnectionStatusSuccess)
+        return 0;
+
+    Error error;
+    size_t bytes_read = dst_len;
+    error = m_read_sp->Read(dst, bytes_read);
+
+    if (log)
+    {
+        log->Printf("%p ConnectionFileDescriptor::Read()  fd = %" PRIu64 ", dst = %p, dst_len = %" PRIu64 ") => %" PRIu64 ", error = %s",
+                    static_cast<void *>(this), static_cast<uint64_t>(m_read_sp->GetWaitableHandle()), static_cast<void *>(dst),
+                    static_cast<uint64_t>(dst_len), static_cast<uint64_t>(bytes_read), error.AsCString());
+    }
+
+    if (bytes_read == 0)
+    {
+        error.Clear(); // End-of-file.  Do not automatically close; pass along for the end-of-file handlers.
+        status = eConnectionStatusEndOfFile;
+    }
+
+    if (error_ptr)
+        *error_ptr = error;
+
+    if (error.Fail())
+    {
+        uint32_t error_value = error.GetError();
+        switch (error_value)
+        {
+            case EAGAIN: // The file was marked for non-blocking I/O, and no data were ready to be read.
+                if (m_read_sp->GetFdType() == IOObject::eFDTypeSocket)
+                    status = eConnectionStatusTimedOut;
+                else
+                    status = eConnectionStatusSuccess;
+                return 0;
+
+            case EFAULT:  // Buf points outside the allocated address space.
+            case EINTR:   // A read from a slow device was interrupted before any data arrived by the delivery of a signal.
+            case EINVAL:  // The pointer associated with fildes was negative.
+            case EIO:     // An I/O error occurred while reading from the file system.
+                          // The process group is orphaned.
+                          // The file is a regular file, nbyte is greater than 0,
+                          // the starting position is before the end-of-file, and
+                          // the starting position is greater than or equal to the
+                          // offset maximum established for the open file
+                          // descriptor associated with fildes.
+            case EISDIR:  // An attempt is made to read a directory.
+            case ENOBUFS: // An attempt to allocate a memory buffer fails.
+            case ENOMEM:  // Insufficient memory is available.
+                status = eConnectionStatusError;
+                break; // Break to close....
+
+            case ENOENT:     // no such file or directory
+            case EBADF:      // fildes is not a valid file or socket descriptor open for reading.
+            case ENXIO:      // An action is requested of a device that does not exist..
+                             // A requested action cannot be performed by the device.
+            case ECONNRESET: // The connection is closed by the peer during a read attempt on a socket.
+            case ENOTCONN:   // A read is attempted on an unconnected socket.
+                status = eConnectionStatusLostConnection;
+                break; // Break to close....
+
+            case ETIMEDOUT: // A transmission timeout occurs during a read attempt on a socket.
+                status = eConnectionStatusTimedOut;
+                return 0;
+
+            default:
+                if (log)
+                    log->Printf("%p ConnectionFileDescriptor::Read (), unexpected error: %s", static_cast<void *>(this),
+                                strerror(error_value));
+                status = eConnectionStatusError;
+                break; // Break to close....
+        }
+
+        return 0;
+    }
+    return bytes_read;
+}
+
+size_t
+ConnectionFileDescriptor::Write(const void *src, size_t src_len, ConnectionStatus &status, Error *error_ptr)
+{
+    Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
+    if (log)
+        log->Printf("%p ConnectionFileDescriptor::Write (src = %p, src_len = %" PRIu64 ")", static_cast<void *>(this),
+                    static_cast<const void *>(src), static_cast<uint64_t>(src_len));
+
+    if (!IsConnected())
+    {
+        if (error_ptr)
+            error_ptr->SetErrorString("not connected");
+        status = eConnectionStatusNoConnection;
+        return 0;
+    }
+
+    Error error;
+
+    size_t bytes_sent = src_len;
+    error = m_write_sp->Write(src, bytes_sent);
+
+    if (log)
+    {
+        log->Printf("%p ConnectionFileDescriptor::Write(fd = %" PRIu64 ", src = %p, src_len = %" PRIu64 ") => %" PRIu64 " (error = %s)",
+                    static_cast<void *>(this), static_cast<uint64_t>(m_write_sp->GetWaitableHandle()), static_cast<const void *>(src),
+                    static_cast<uint64_t>(src_len), static_cast<uint64_t>(bytes_sent), error.AsCString());
+    }
+
+    if (error_ptr)
+        *error_ptr = error;
+
+    if (error.Fail())
+    {
+        switch (error.GetError())
+        {
+            case EAGAIN:
+            case EINTR:
+                status = eConnectionStatusSuccess;
+                return 0;
+
+            case ECONNRESET: // The connection is closed by the peer during a read attempt on a socket.
+            case ENOTCONN:   // A read is attempted on an unconnected socket.
+                status = eConnectionStatusLostConnection;
+                break; // Break to close....
+
+            default:
+                status = eConnectionStatusError;
+                break; // Break to close....
+        }
+
+        return 0;
+    }
+
+    status = eConnectionStatusSuccess;
+    return bytes_sent;
+}
+
+// This ConnectionFileDescriptor::BytesAvailable() uses select().
+//
+// PROS:
+//  - select is consistent across most unix platforms
+//  - The Apple specific version allows for unlimited fds in the fd_sets by
+//    setting the _DARWIN_UNLIMITED_SELECT define prior to including the
+//    required header files.
+// CONS:
+//  - on non-Apple platforms, only supports file descriptors up to FD_SETSIZE.
+//     This implementation  will assert if it runs into that hard limit to let
+//     users know that another ConnectionFileDescriptor::BytesAvailable() should
+//     be used or a new version of ConnectionFileDescriptor::BytesAvailable()
+//     should be written for the system that is running into the limitations.
+
+#if defined(__APPLE__)
+#define FD_SET_DATA(fds) fds.data()
+#else
+#define FD_SET_DATA(fds) &fds
+#endif
+
+ConnectionStatus
+ConnectionFileDescriptor::BytesAvailable(uint32_t timeout_usec, Error *error_ptr)
+{
+    // Don't need to take the mutex here separately since we are only called from Read.  If we
+    // ever get used more generally we will need to lock here as well.
+
+    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_CONNECTION));
+    if (log)
+        log->Printf("%p ConnectionFileDescriptor::BytesAvailable (timeout_usec = %u)", static_cast<void *>(this), timeout_usec);
+
+    struct timeval *tv_ptr;
+    struct timeval tv;
+    if (timeout_usec == UINT32_MAX)
+    {
+        // Inifinite wait...
+        tv_ptr = nullptr;
+    }
+    else
+    {
+        TimeValue time_value;
+        time_value.OffsetWithMicroSeconds(timeout_usec);
+        tv.tv_sec = time_value.seconds();
+        tv.tv_usec = time_value.microseconds();
+        tv_ptr = &tv;
+    }
+
+    // Make a copy of the file descriptors to make sure we don't
+    // have another thread change these values out from under us
+    // and cause problems in the loop below where like in FS_SET()
+    const IOObject::WaitableHandle handle = m_read_sp->GetWaitableHandle();
+    const int pipe_fd = m_pipe.GetReadFileDescriptor();
+
+    if (handle != IOObject::kInvalidHandleValue)
+    {
+#if defined(_MSC_VER)
+        // select() won't accept pipes on Windows.  The entire Windows codepath needs to be
+        // converted over to using WaitForMultipleObjects and event HANDLEs, but for now at least
+        // this will allow ::select() to not return an error.
+        const bool have_pipe_fd = false;
+#else
+        const bool have_pipe_fd = pipe_fd >= 0;
+#if !defined(__APPLE__)
+        assert(handle < FD_SETSIZE);
+        if (have_pipe_fd)
+            assert(pipe_fd < FD_SETSIZE);
+#endif
+#endif
+        while (handle == m_read_sp->GetWaitableHandle())
+        {
+            const int nfds = std::max<int>(handle, pipe_fd) + 1;
+#if defined(__APPLE__)
+            llvm::SmallVector<fd_set, 1> read_fds;
+            read_fds.resize((nfds / FD_SETSIZE) + 1);
+            for (size_t i = 0; i < read_fds.size(); ++i)
+                FD_ZERO(&read_fds[i]);
+// FD_SET doesn't bounds check, it just happily walks off the end
+// but we have taken care of making the extra storage with our
+// SmallVector of fd_set objects
+#else
+            fd_set read_fds;
+            FD_ZERO(&read_fds);
+#endif
+            FD_SET(handle, FD_SET_DATA(read_fds));
+            if (have_pipe_fd)
+                FD_SET(pipe_fd, FD_SET_DATA(read_fds));
+
+            Error error;
+
+            if (log)
+            {
+                if (have_pipe_fd)
+                    log->Printf(
+                        "%p ConnectionFileDescriptor::BytesAvailable()  ::select (nfds=%i, fds={%i, %i}, NULL, NULL, timeout=%p)...",
+                        static_cast<void *>(this), nfds, handle, pipe_fd, static_cast<void *>(tv_ptr));
+                else
+                    log->Printf("%p ConnectionFileDescriptor::BytesAvailable()  ::select (nfds=%i, fds={%i}, NULL, NULL, timeout=%p)...",
+                                static_cast<void *>(this), nfds, handle, static_cast<void *>(tv_ptr));
+            }
+
+            const int num_set_fds = ::select(nfds, FD_SET_DATA(read_fds), NULL, NULL, tv_ptr);
+            if (num_set_fds < 0)
+                error.SetErrorToErrno();
+            else
+                error.Clear();
+
+            if (log)
+            {
+                if (have_pipe_fd)
+                    log->Printf("%p ConnectionFileDescriptor::BytesAvailable()  ::select (nfds=%i, fds={%i, %i}, NULL, NULL, timeout=%p) "
+                                "=> %d, error = %s",
+                                static_cast<void *>(this), nfds, handle, pipe_fd, static_cast<void *>(tv_ptr), num_set_fds,
+                                error.AsCString());
+                else
+                    log->Printf("%p ConnectionFileDescriptor::BytesAvailable()  ::select (nfds=%i, fds={%i}, NULL, NULL, timeout=%p) => "
+                                "%d, error = %s",
+                                static_cast<void *>(this), nfds, handle, static_cast<void *>(tv_ptr), num_set_fds, error.AsCString());
+            }
+
+            if (error_ptr)
+                *error_ptr = error;
+
+            if (error.Fail())
+            {
+                switch (error.GetError())
+                {
+                    case EBADF: // One of the descriptor sets specified an invalid descriptor.
+                        return eConnectionStatusLostConnection;
+
+                    case EINVAL: // The specified time limit is invalid. One of its components is negative or too large.
+                    default:     // Other unknown error
+                        return eConnectionStatusError;
+
+                    case EAGAIN: // The kernel was (perhaps temporarily) unable to
+                                 // allocate the requested number of file descriptors,
+                                 // or we have non-blocking IO
+                    case EINTR:  // A signal was delivered before the time limit
+                        // expired and before any of the selected events
+                        // occurred.
+                        break; // Lets keep reading to until we timeout
+                }
+            }
+            else if (num_set_fds == 0)
+            {
+                return eConnectionStatusTimedOut;
+            }
+            else if (num_set_fds > 0)
+            {
+                if (FD_ISSET(handle, FD_SET_DATA(read_fds)))
+                    return eConnectionStatusSuccess;
+                if (have_pipe_fd && FD_ISSET(pipe_fd, FD_SET_DATA(read_fds)))
+                {
+                    // We got a command to exit.  Read the data from that pipe:
+                    char buffer[16];
+                    ssize_t bytes_read;
+
+                    do
+                    {
+                        bytes_read = ::read(pipe_fd, buffer, sizeof(buffer));
+                    } while (bytes_read < 0 && errno == EINTR);
+
+                    switch (buffer[0])
+                    {
+                        case 'q':
+                            if (log)
+                                log->Printf("%p ConnectionFileDescriptor::BytesAvailable() got data: %*s from the command channel.",
+                                            static_cast<void *>(this), static_cast<int>(bytes_read), buffer);
+                            return eConnectionStatusEndOfFile;
+                        case 'i':
+                            // Interrupt the current read
+                            return eConnectionStatusInterrupted;
+                    }
+                }
+            }
+        }
+    }
+
+    if (error_ptr)
+        error_ptr->SetErrorString("not connected");
+    return eConnectionStatusLostConnection;
+}
+
+ConnectionStatus
+ConnectionFileDescriptor::NamedSocketAccept(const char *socket_name, Error *error_ptr)
+{
+    Socket *socket = nullptr;
+    Error error = Socket::UnixDomainAccept(socket_name, socket);
+    if (error_ptr)
+        *error_ptr = error;
+    m_write_sp.reset(socket);
+    m_read_sp = m_write_sp;
+    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
+}
+
+ConnectionStatus
+ConnectionFileDescriptor::NamedSocketConnect(const char *socket_name, Error *error_ptr)
+{
+    Socket *socket = nullptr;
+    Error error = Socket::UnixDomainConnect(socket_name, socket);
+    if (error_ptr)
+        *error_ptr = error;
+    m_write_sp.reset(socket);
+    m_read_sp = m_write_sp;
+    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
+}
+
+ConnectionStatus
+ConnectionFileDescriptor::SocketListen(const char *s, Error *error_ptr)
+{
+    m_port_predicate.SetValue(0, eBroadcastNever);
+
+    Socket *socket = nullptr;
+    m_waiting_for_accept = true;
+    Error error = Socket::TcpListen(s, socket, &m_port_predicate);
+    if (error_ptr)
+        *error_ptr = error;
+    if (error.Fail())
+        return eConnectionStatusError;
+
+    std::unique_ptr<Socket> listening_socket_up;
+
+    listening_socket_up.reset(socket);
+    socket = nullptr;
+    error = listening_socket_up->BlockingAccept(s, socket);
+    listening_socket_up.reset();
+    if (error_ptr)
+        *error_ptr = error;
+    if (error.Fail())
+        return eConnectionStatusError;
+
+    m_write_sp.reset(socket);
+    m_read_sp = m_write_sp;
+    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
+}
+
+ConnectionStatus
+ConnectionFileDescriptor::ConnectTCP(const char *s, Error *error_ptr)
+{
+    Socket *socket = nullptr;
+    Error error = Socket::TcpConnect(s, socket);
+    if (error_ptr)
+        *error_ptr = error;
+    m_write_sp.reset(socket);
+    m_read_sp = m_write_sp;
+    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
+}
+
+ConnectionStatus
+ConnectionFileDescriptor::ConnectUDP(const char *s, Error *error_ptr)
+{
+    Socket *send_socket = nullptr;
+    Socket *recv_socket = nullptr;
+    Error error = Socket::UdpConnect(s, send_socket, recv_socket);
+    if (error_ptr)
+        *error_ptr = error;
+    m_write_sp.reset(send_socket);
+    m_read_sp.reset(recv_socket);
+    return (error.Success()) ? eConnectionStatusSuccess : eConnectionStatusError;
+}
+
+uint16_t
+ConnectionFileDescriptor::GetListeningPort(uint32_t timeout_sec)
+{
+    uint16_t bound_port = 0;
+    if (timeout_sec == UINT32_MAX)
+        m_port_predicate.WaitForValueNotEqualTo(0, bound_port);
+    else
+    {
+        TimeValue timeout = TimeValue::Now();
+        timeout.OffsetWithSeconds(timeout_sec);
+        m_port_predicate.WaitForValueNotEqualTo(0, bound_port, &timeout);
+    }
+    return bound_port;
+}