Switch over to using socketpair for local debugserver connections as they are twice as fast as TCP sockets (on macOS at least).

This change opens a socket pair and passes the second socket pair file descriptor down to the debugserver binary using a new option: "--fd=N" where N is the file descriptor. This file descriptor gets passed via posix_spawn() so that there is no need to do any bind/listen or bind/accept calls and eliminates the hanshake unix socket that is used to pass the result of the actual port that ends up being used so it can save time on launch as well as being faster.

This is currently only enabled on __APPLE__ builds. Other OSs should try modifying the #define from ProcessGDBRemote.cpp but the first person will need to port the --fd option over to lldb-server. Any OSs that enable USE_SOCKETPAIR_FOR_LOCAL_CONNECTION in their native builds can use the socket pair stuff. The #define is Apple only right now, but looks like:

#if defined (__APPLE__)
#define USE_SOCKETPAIR_FOR_LOCAL_CONNECTION 1
#endif

<rdar://problem/27814880> 

llvm-svn: 278524
This commit is contained in:
Greg Clayton 2016-08-12 16:46:18 +00:00
parent 623c4c1572
commit c6c420fca1
5 changed files with 118 additions and 33 deletions

View File

@ -1091,7 +1091,8 @@ GDBRemoteCommunication::StartDebugserverProcess (const char *url,
Platform *platform, Platform *platform,
ProcessLaunchInfo &launch_info, ProcessLaunchInfo &launch_info,
uint16_t *port, uint16_t *port,
const Args& inferior_args) const Args* inferior_args,
int pass_comm_fd)
{ {
Log *log (ProcessGDBRemoteLog::GetLogIfAllCategoriesSet (GDBR_LOG_PROCESS)); Log *log (ProcessGDBRemoteLog::GetLogIfAllCategoriesSet (GDBR_LOG_PROCESS));
if (log) if (log)
@ -1171,6 +1172,16 @@ GDBRemoteCommunication::StartDebugserverProcess (const char *url,
if (url) if (url)
debugserver_args.AppendArgument(url); debugserver_args.AppendArgument(url);
if (pass_comm_fd >= 0)
{
StreamString fd_arg;
fd_arg.Printf("--fd=%i", pass_comm_fd);
debugserver_args.AppendArgument(fd_arg.GetData());
// Send "pass_comm_fd" down to the inferior so it can use it to
// communicate back with this process
launch_info.AppendDuplicateFileAction(pass_comm_fd, pass_comm_fd);
}
// use native registers, not the GDB registers // use native registers, not the GDB registers
debugserver_args.AppendArgument("--native-regs"); debugserver_args.AppendArgument("--native-regs");
@ -1189,7 +1200,7 @@ GDBRemoteCommunication::StartDebugserverProcess (const char *url,
// port is null when debug server should listen on domain socket - // port is null when debug server should listen on domain socket -
// we're not interested in port value but rather waiting for debug server // we're not interested in port value but rather waiting for debug server
// to become available. // to become available.
if ((port != nullptr && *port == 0) || port == nullptr) if (pass_comm_fd == -1 && ((port != nullptr && *port == 0) || port == nullptr))
{ {
if (url) if (url)
{ {
@ -1304,10 +1315,10 @@ GDBRemoteCommunication::StartDebugserverProcess (const char *url,
} }
} while (has_env_var); } while (has_env_var);
if (inferior_args.GetArgumentCount() > 0) if (inferior_args && inferior_args->GetArgumentCount() > 0)
{ {
debugserver_args.AppendArgument ("--"); debugserver_args.AppendArgument ("--");
debugserver_args.AppendArguments (inferior_args); debugserver_args.AppendArguments (*inferior_args);
} }
// Copy the current environment to the gdbserver/debugserver instance // Copy the current environment to the gdbserver/debugserver instance
@ -1337,8 +1348,7 @@ GDBRemoteCommunication::StartDebugserverProcess (const char *url,
} }
error = Host::LaunchProcess(launch_info); error = Host::LaunchProcess(launch_info);
if (error.Success() && if (error.Success() && (launch_info.GetProcessID() != LLDB_INVALID_PROCESS_ID) && pass_comm_fd == -1)
launch_info.GetProcessID() != LLDB_INVALID_PROCESS_ID)
{ {
if (named_pipe_path.size() > 0) if (named_pipe_path.size() > 0)
{ {

View File

@ -162,7 +162,8 @@ public:
Platform *platform, // If non nullptr, then check with the platform for the GDB server binary if it can't be located Platform *platform, // If non nullptr, then check with the platform for the GDB server binary if it can't be located
ProcessLaunchInfo &launch_info, ProcessLaunchInfo &launch_info,
uint16_t *port, uint16_t *port,
const Args& inferior_args = Args()); const Args *inferior_args,
int pass_comm_fd); // Communication file descriptor to pass during fork/exec to avoid having to connect/accept
void void
DumpHistory(Stream &strm); DumpHistory(Stream &strm);

View File

@ -149,7 +149,8 @@ GDBRemoteCommunicationServerPlatform::LaunchGDBServer(const lldb_private::Args&
nullptr, nullptr,
debugserver_launch_info, debugserver_launch_info,
port_ptr, port_ptr,
args); &args,
-1);
pid = debugserver_launch_info.GetProcessID(); pid = debugserver_launch_info.GetProcessID();
if (pid != LLDB_INVALID_PROCESS_ID) if (pid != LLDB_INVALID_PROCESS_ID)

View File

@ -16,6 +16,7 @@
#include <netinet/in.h> #include <netinet/in.h>
#include <sys/mman.h> // for mmap #include <sys/mman.h> // for mmap
#endif #endif
#include <sys/socket.h>
#include <sys/stat.h> #include <sys/stat.h>
#include <sys/types.h> #include <sys/types.h>
#include <time.h> #include <time.h>
@ -64,6 +65,7 @@
#include "lldb/Target/TargetList.h" #include "lldb/Target/TargetList.h"
#include "lldb/Target/ThreadPlanCallFunction.h" #include "lldb/Target/ThreadPlanCallFunction.h"
#include "lldb/Target/SystemRuntime.h" #include "lldb/Target/SystemRuntime.h"
#include "lldb/Utility/CleanUp.h"
#include "lldb/Utility/PseudoTerminal.h" #include "lldb/Utility/PseudoTerminal.h"
// Project includes // Project includes
@ -3602,6 +3604,23 @@ ProcessGDBRemote::EstablishConnectionIfNeeded (const ProcessInfo &process_info)
} }
return error; return error;
} }
#if defined (__APPLE__)
#define USE_SOCKETPAIR_FOR_LOCAL_CONNECTION 1
#endif
#ifdef USE_SOCKETPAIR_FOR_LOCAL_CONNECTION
static bool SetCloexecFlag(int fd)
{
#if defined(FD_CLOEXEC)
int flags = ::fcntl(fd, F_GETFD);
if (flags == -1)
return false;
return (::fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == 0);
#else
return false;
#endif
}
#endif
Error Error
ProcessGDBRemote::LaunchAndConnectToDebugserver (const ProcessInfo &process_info) ProcessGDBRemote::LaunchAndConnectToDebugserver (const ProcessInfo &process_info)
@ -3624,30 +3643,34 @@ ProcessGDBRemote::LaunchAndConnectToDebugserver (const ProcessInfo &process_info
false); false);
debugserver_launch_info.SetUserID(process_info.GetUserID()); debugserver_launch_info.SetUserID(process_info.GetUserID());
#if defined (__APPLE__) && (defined (__arm__) || defined (__arm64__) || defined (__aarch64__))
// On iOS, still do a local connection using a random port
const char *hostname = "127.0.0.1";
uint16_t port = get_random_port ();
#else
// Set hostname being NULL to do the reverse connect where debugserver
// will bind to port zero and it will communicate back to us the port
// that we will connect to
const char *hostname = nullptr;
uint16_t port = 0;
#endif
StreamString url_str; int communication_fd = -1;
const char* url = nullptr; #ifdef USE_SOCKETPAIR_FOR_LOCAL_CONNECTION
if (hostname != nullptr) // Auto close the sockets we might open up unless everything goes OK. This
// helps us not leak file descriptors when things go wrong.
lldb_utility::CleanUp <int, int> our_socket(-1, -1, close);
lldb_utility::CleanUp <int, int> gdb_socket(-1, -1, close);
// Use a socketpair on Apple for now until other platforms can verify it
// works and is fast enough
{ {
url_str.Printf("%s:%u", hostname, port); int sockets[2]; /* the pair of socket descriptors */
url = url_str.GetData(); if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) == -1)
{
error.SetErrorToErrno();
return error;
}
our_socket.set(sockets[0]);
gdb_socket.set(sockets[1]);
} }
error = m_gdb_comm.StartDebugserverProcess (url, // Don't let any child processes inherit our communication socket
GetTarget().GetPlatform().get(), SetCloexecFlag(our_socket.get());
debugserver_launch_info, communication_fd = gdb_socket.get();
&port); #endif
error = m_gdb_comm.StartDebugserverProcess(nullptr, GetTarget().GetPlatform().get(), debugserver_launch_info, nullptr, nullptr, communication_fd);
if (error.Success ()) if (error.Success ())
m_debugserver_pid = debugserver_launch_info.GetProcessID(); m_debugserver_pid = debugserver_launch_info.GetProcessID();
@ -3655,7 +3678,14 @@ ProcessGDBRemote::LaunchAndConnectToDebugserver (const ProcessInfo &process_info
m_debugserver_pid = LLDB_INVALID_PROCESS_ID; m_debugserver_pid = LLDB_INVALID_PROCESS_ID;
if (m_debugserver_pid != LLDB_INVALID_PROCESS_ID) if (m_debugserver_pid != LLDB_INVALID_PROCESS_ID)
{
#ifdef USE_SOCKETPAIR_FOR_LOCAL_CONNECTION
// Our process spawned correctly, we can now set our connection to use our
// end of the socket pair
m_gdb_comm.SetConnection(new ConnectionFileDescriptor(our_socket.release(), true));
#endif
StartAsyncThread (); StartAsyncThread ();
}
if (error.Fail()) if (error.Fail())
{ {
@ -3669,13 +3699,11 @@ ProcessGDBRemote::LaunchAndConnectToDebugserver (const ProcessInfo &process_info
if (m_gdb_comm.IsConnected()) if (m_gdb_comm.IsConnected())
{ {
// Finish the connection process by doing the handshake without connecting (send NULL URL) // Finish the connection process by doing the handshake without connecting (send NULL URL)
ConnectToDebugserver (NULL); ConnectToDebugserver(NULL);
} }
else else
{ {
StreamString connect_url; error.SetErrorString("connection failed");
connect_url.Printf("connect://%s:%u", hostname, port);
error = ConnectToDebugserver (connect_url.GetString().c_str());
} }
} }

View File

@ -872,6 +872,7 @@ static struct option g_long_options[] =
{ "working-dir", required_argument, NULL, 'W' }, // The working directory that the inferior process should have (only if debugserver launches the process) { "working-dir", required_argument, NULL, 'W' }, // The working directory that the inferior process should have (only if debugserver launches the process)
{ "platform", required_argument, NULL, 'p' }, // Put this executable into a remote platform mode { "platform", required_argument, NULL, 'p' }, // Put this executable into a remote platform mode
{ "unix-socket", required_argument, NULL, 'u' }, // If we need to handshake with our parent process, an option will be passed down that specifies a unix socket name to use { "unix-socket", required_argument, NULL, 'u' }, // If we need to handshake with our parent process, an option will be passed down that specifies a unix socket name to use
{ "fd", required_argument, NULL, 'FDSC' }, // A file descriptor was passed to this process when spawned that is already open and ready for communication
{ "named-pipe", required_argument, NULL, 'P' }, { "named-pipe", required_argument, NULL, 'P' },
{ "reverse-connect", no_argument, NULL, 'R' }, { "reverse-connect", no_argument, NULL, 'R' },
{ "env", required_argument, NULL, 'e' }, // When debugserver launches the process, set a single environment entry as specified by the option value ("./debugserver -e FOO=1 -e BAR=2 localhost:1234 -- /bin/ls") { "env", required_argument, NULL, 'e' }, // When debugserver launches the process, set a single environment entry as specified by the option value ("./debugserver -e FOO=1 -e BAR=2 localhost:1234 -- /bin/ls")
@ -949,6 +950,7 @@ main (int argc, char *argv[])
int ch; int ch;
int long_option_index = 0; int long_option_index = 0;
int debug = 0; int debug = 0;
int communication_fd = -1;
std::string compile_options; std::string compile_options;
std::string waitfor_pid_name; // Wait for a process that starts with this name std::string waitfor_pid_name; // Wait for a process that starts with this name
std::string attach_pid_name; std::string attach_pid_name;
@ -1248,6 +1250,12 @@ main (int argc, char *argv[])
remote->Context().PushEnvironment(env_entry); remote->Context().PushEnvironment(env_entry);
} }
break; break;
case 'FDSC':
// File descriptor passed to this process during fork/exec and is already
// open and ready for communication.
communication_fd = atoi(optarg);
break;
} }
} }
@ -1324,7 +1332,7 @@ main (int argc, char *argv[])
char str[PATH_MAX]; char str[PATH_MAX];
str[0] = '\0'; str[0] = '\0';
if (g_lockdown_opt == 0 && g_applist_opt == 0) if (g_lockdown_opt == 0 && g_applist_opt == 0 && communication_fd == -1)
{ {
// Make sure we at least have port // Make sure we at least have port
if (argc < 1) if (argc < 1)
@ -1475,6 +1483,15 @@ main (int argc, char *argv[])
if (remote->Comm().OpenFile (str)) if (remote->Comm().OpenFile (str))
mode = eRNBRunLoopModeExit; mode = eRNBRunLoopModeExit;
} }
else if (communication_fd >= 0)
{
// We were passed a file descriptor to use during fork/exec that is already open
// in our process, so lets just use it!
if (remote->Comm().useFD(communication_fd))
mode = eRNBRunLoopModeExit;
else
remote->StartReadRemoteDataThread();
}
if (mode != eRNBRunLoopModeExit) if (mode != eRNBRunLoopModeExit)
{ {
@ -1600,6 +1617,16 @@ main (int argc, char *argv[])
if (remote->Comm().OpenFile (str)) if (remote->Comm().OpenFile (str))
mode = eRNBRunLoopModeExit; mode = eRNBRunLoopModeExit;
} }
else if (communication_fd >= 0)
{
// We were passed a file descriptor to use during fork/exec that is already open
// in our process, so lets just use it!
if (remote->Comm().useFD(communication_fd))
mode = eRNBRunLoopModeExit;
else
remote->StartReadRemoteDataThread();
}
if (mode != eRNBRunLoopModeExit) if (mode != eRNBRunLoopModeExit)
RNBLogSTDOUT ("Waiting for debugger instructions for process %d.\n", attach_pid); RNBLogSTDOUT ("Waiting for debugger instructions for process %d.\n", attach_pid);
} }
@ -1625,6 +1652,15 @@ main (int argc, char *argv[])
if (remote->Comm().OpenFile (str)) if (remote->Comm().OpenFile (str))
mode = eRNBRunLoopModeExit; mode = eRNBRunLoopModeExit;
} }
else if (communication_fd >= 0)
{
// We were passed a file descriptor to use during fork/exec that is already open
// in our process, so lets just use it!
if (remote->Comm().useFD(communication_fd))
mode = eRNBRunLoopModeExit;
else
remote->StartReadRemoteDataThread();
}
if (mode != eRNBRunLoopModeExit) if (mode != eRNBRunLoopModeExit)
{ {
@ -1657,6 +1693,15 @@ main (int argc, char *argv[])
if (remote->Comm().OpenFile (str)) if (remote->Comm().OpenFile (str))
mode = eRNBRunLoopModeExit; mode = eRNBRunLoopModeExit;
} }
else if (communication_fd >= 0)
{
// We were passed a file descriptor to use during fork/exec that is already open
// in our process, so lets just use it!
if (remote->Comm().useFD(communication_fd))
mode = eRNBRunLoopModeExit;
else
remote->StartReadRemoteDataThread();
}
if (mode != eRNBRunLoopModeExit) if (mode != eRNBRunLoopModeExit)
mode = RNBRunLoopPlatform (remote); mode = RNBRunLoopPlatform (remote);