teak-llvm/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
Pavel Labath e768c4b858 Rewrite gdb-remote's SendContinuePacketAndWaitForResponse
SendContinuePacketAndWaitForResponse was huge function with very complex interactions with
several other functions (SendAsyncSignal, SendInterrupt, SendPacket). This meant that making any
changes to how packet sending functions and threads interact was very difficult and error-prone.

This change does not add any functionality yet, it merely paves the way for future changes. In a
follow-up, I plan to add the ability to have multiple query packets in flight (i.e.,
request,request,response,response instead of the usual request,response sequences) and use that
to speed up qModuleInfo packet processing.

Here, I introduce two special kinds of locks: ContinueLock, which is used by the continue thread,
and Lock, which is used by everyone else. ContinueLock (atomically) sends a continue packet, and
blocks any other async threads from accessing the connection. Other threads create an instance of
the Lock object when they want to access the connection. This object, while in scope prevents the
continue from being send. Optionally, it can also interrupt the process to gain access to the
connection for async processing.

Most of the syncrhonization logic is encapsulated within these two classes. Some of it still
had to bleed over into the SendContinuePacketAndWaitForResponse, but the function is still much
more manageable than before -- partly because of most of the work is done in the ContinueLock
class, and partly because I have factored out a lot of the packet processing code separate
functions (this also makes the functionality more easily testable). Most importantly, there is
none of syncrhonization code in the async thread users -- as far as they are concerned, they just
need to declare a Lock object, and they are good to go (SendPacketAndWaitForResponse is now a
very thin wrapper around the NoLock version of the function, whereas previously it had over 100
lines of synchronization code).  This will make my follow up changes there easy.

I have written a number of unit tests for the new code and I have ran the test suite on linux and
osx with no regressions.

Subscribers: tberghammer

Differential Revision: https://reviews.llvm.org/D22629

llvm-svn: 277139
2016-07-29 13:10:02 +00:00

637 lines
20 KiB
C++

//===-- GDBRemoteCommunicationClient.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_GDBRemoteCommunicationClient_h_
#define liblldb_GDBRemoteCommunicationClient_h_
// C Includes
// C++ Includes
#include <chrono>
#include <map>
#include <mutex>
#include <string>
#include <vector>
// Other libraries and framework includes
// Project includes
#include "lldb/Core/ArchSpec.h"
#include "lldb/Core/StructuredData.h"
#include "lldb/Target/Process.h"
#include "GDBRemoteClientBase.h"
namespace lldb_private {
namespace process_gdb_remote {
class GDBRemoteCommunicationClient : public GDBRemoteClientBase
{
public:
GDBRemoteCommunicationClient();
~GDBRemoteCommunicationClient() override;
//------------------------------------------------------------------
// After connecting, send the handshake to the server to make sure
// we are communicating with it.
//------------------------------------------------------------------
bool
HandshakeWithServer (Error *error_ptr);
// For packets which specify a range of output to be returned,
// return all of the output via a series of request packets of the form
// <prefix>0,<size>
// <prefix><size>,<size>
// <prefix><size>*2,<size>
// <prefix><size>*3,<size>
// ...
// until a "$l..." packet is received, indicating the end.
// (size is in hex; this format is used by a standard gdbserver to
// return the given portion of the output specified by <prefix>;
// for example, "qXfer:libraries-svr4:read::fff,1000" means
// "return a chunk of the xml description file for shared
// library load addresses, where the chunk starts at offset 0xfff
// and continues for 0x1000 bytes").
// Concatenate the resulting server response packets together and
// return in response_string. If any packet fails, the return value
// indicates that failure and the returned string value is undefined.
PacketResult
SendPacketsAndConcatenateResponses (const char *send_payload_prefix,
std::string &response_string);
bool
GetThreadSuffixSupported () override;
// This packet is usually sent first and the boolean return value
// indicates if the packet was send and any response was received
// even in the response is UNIMPLEMENTED. If the packet failed to
// get a response, then false is returned. This quickly tells us
// if we were able to connect and communicate with the remote GDB
// server
bool
QueryNoAckModeSupported ();
void
GetListThreadsInStopReplySupported ();
lldb::pid_t
GetCurrentProcessID (bool allow_lazy = true);
bool
GetLaunchSuccess (std::string &error_str);
bool
LaunchGDBServer (const char *remote_accept_hostname,
lldb::pid_t &pid,
uint16_t &port,
std::string &socket_name);
size_t
QueryGDBServer (std::vector<std::pair<uint16_t, std::string>>& connection_urls);
bool
KillSpawnedProcess (lldb::pid_t pid);
//------------------------------------------------------------------
/// Sends a GDB remote protocol 'A' packet that delivers program
/// arguments to the remote server.
///
/// @param[in] argv
/// A NULL terminated array of const C strings to use as the
/// arguments.
///
/// @return
/// Zero if the response was "OK", a positive value if the
/// the response was "Exx" where xx are two hex digits, or
/// -1 if the call is unsupported or any other unexpected
/// response was received.
//------------------------------------------------------------------
int
SendArgumentsPacket (const ProcessLaunchInfo &launch_info);
//------------------------------------------------------------------
/// Sends a "QEnvironment:NAME=VALUE" packet that will build up the
/// environment that will get used when launching an application
/// in conjunction with the 'A' packet. This function can be called
/// multiple times in a row in order to pass on the desired
/// environment that the inferior should be launched with.
///
/// @param[in] name_equal_value
/// A NULL terminated C string that contains a single environment
/// in the format "NAME=VALUE".
///
/// @return
/// Zero if the response was "OK", a positive value if the
/// the response was "Exx" where xx are two hex digits, or
/// -1 if the call is unsupported or any other unexpected
/// response was received.
//------------------------------------------------------------------
int
SendEnvironmentPacket (char const *name_equal_value);
int
SendLaunchArchPacket (const char *arch);
int
SendLaunchEventDataPacket(const char *data, bool *was_supported = nullptr);
//------------------------------------------------------------------
/// Sends a "vAttach:PID" where PID is in hex.
///
/// @param[in] pid
/// A process ID for the remote gdb server to attach to.
///
/// @param[out] response
/// The response received from the gdb server. If the return
/// value is zero, \a response will contain a stop reply
/// packet.
///
/// @return
/// Zero if the attach was successful, or an error indicating
/// an error code.
//------------------------------------------------------------------
int
SendAttach (lldb::pid_t pid,
StringExtractorGDBRemote& response);
//------------------------------------------------------------------
/// Sends a GDB remote protocol 'I' packet that delivers stdin
/// data to the remote process.
///
/// @param[in] data
/// A pointer to stdin data.
///
/// @param[in] data_len
/// The number of bytes available at \a data.
///
/// @return
/// Zero if the attach was successful, or an error indicating
/// an error code.
//------------------------------------------------------------------
int
SendStdinNotification(const char* data, size_t data_len);
//------------------------------------------------------------------
/// Sets the path to use for stdin/out/err for a process
/// that will be launched with the 'A' packet.
///
/// @param[in] path
/// The path to use for stdin/out/err
///
/// @return
/// Zero if the for success, or an error code for failure.
//------------------------------------------------------------------
int
SetSTDIN(const FileSpec &file_spec);
int
SetSTDOUT(const FileSpec &file_spec);
int
SetSTDERR(const FileSpec &file_spec);
//------------------------------------------------------------------
/// Sets the disable ASLR flag to \a enable for a process that will
/// be launched with the 'A' packet.
///
/// @param[in] enable
/// A boolean value indicating whether to disable ASLR or not.
///
/// @return
/// Zero if the for success, or an error code for failure.
//------------------------------------------------------------------
int
SetDisableASLR (bool enable);
//------------------------------------------------------------------
/// Sets the DetachOnError flag to \a enable for the process controlled by the stub.
///
/// @param[in] enable
/// A boolean value indicating whether to detach on error or not.
///
/// @return
/// Zero if the for success, or an error code for failure.
//------------------------------------------------------------------
int
SetDetachOnError (bool enable);
//------------------------------------------------------------------
/// Sets the working directory to \a path for a process that will
/// be launched with the 'A' packet for non platform based
/// connections. If this packet is sent to a GDB server that
/// implements the platform, it will change the current working
/// directory for the platform process.
///
/// @param[in] working_dir
/// The path to a directory to use when launching our process
///
/// @return
/// Zero if the for success, or an error code for failure.
//------------------------------------------------------------------
int
SetWorkingDir(const FileSpec &working_dir);
//------------------------------------------------------------------
/// Gets the current working directory of a remote platform GDB
/// server.
///
/// @param[out] working_dir
/// The current working directory on the remote platform.
///
/// @return
/// Boolean for success
//------------------------------------------------------------------
bool
GetWorkingDir(FileSpec &working_dir);
lldb::addr_t
AllocateMemory (size_t size, uint32_t permissions);
bool
DeallocateMemory (lldb::addr_t addr);
Error
Detach (bool keep_stopped);
Error
GetMemoryRegionInfo (lldb::addr_t addr, MemoryRegionInfo &range_info);
Error
GetWatchpointSupportInfo (uint32_t &num);
Error
GetWatchpointSupportInfo (uint32_t &num, bool& after, const ArchSpec &arch);
Error
GetWatchpointsTriggerAfterInstruction (bool &after, const ArchSpec &arch);
const ArchSpec &
GetHostArchitecture ();
uint32_t
GetHostDefaultPacketTimeout();
const ArchSpec &
GetProcessArchitecture ();
void
GetRemoteQSupported();
bool
GetVContSupported (char flavor);
bool
GetpPacketSupported (lldb::tid_t tid);
bool
GetxPacketSupported ();
bool
GetVAttachOrWaitSupported ();
bool
GetSyncThreadStateSupported();
void
ResetDiscoverableSettings (bool did_exec);
bool
GetHostInfo (bool force = false);
bool
GetDefaultThreadId (lldb::tid_t &tid);
bool
GetOSVersion (uint32_t &major,
uint32_t &minor,
uint32_t &update);
bool
GetOSBuildString (std::string &s);
bool
GetOSKernelDescription (std::string &s);
ArchSpec
GetSystemArchitecture ();
bool
GetHostname (std::string &s);
lldb::addr_t
GetShlibInfoAddr();
bool
GetSupportsThreadSuffix ();
bool
GetProcessInfo (lldb::pid_t pid, ProcessInstanceInfo &process_info);
uint32_t
FindProcesses (const ProcessInstanceInfoMatch &process_match_info,
ProcessInstanceInfoList &process_infos);
bool
GetUserName (uint32_t uid, std::string &name);
bool
GetGroupName (uint32_t gid, std::string &name);
bool
HasFullVContSupport ()
{
return GetVContSupported ('A');
}
bool
HasAnyVContSupport ()
{
return GetVContSupported ('a');
}
bool
GetStopReply (StringExtractorGDBRemote &response);
bool
GetThreadStopInfo (lldb::tid_t tid,
StringExtractorGDBRemote &response);
bool
SupportsGDBStoppointPacket (GDBStoppointType type)
{
switch (type)
{
case eBreakpointSoftware: return m_supports_z0;
case eBreakpointHardware: return m_supports_z1;
case eWatchpointWrite: return m_supports_z2;
case eWatchpointRead: return m_supports_z3;
case eWatchpointReadWrite: return m_supports_z4;
default: return false;
}
}
uint8_t
SendGDBStoppointTypePacket (GDBStoppointType type, // Type of breakpoint or watchpoint
bool insert, // Insert or remove?
lldb::addr_t addr, // Address of breakpoint or watchpoint
uint32_t length); // Byte Size of breakpoint or watchpoint
bool
SetNonStopMode (const bool enable);
void
TestPacketSpeed (const uint32_t num_packets, uint32_t max_send, uint32_t max_recv, bool json, Stream &strm);
// This packet is for testing the speed of the interface only. Both
// the client and server need to support it, but this allows us to
// measure the packet speed without any other work being done on the
// other end and avoids any of that work affecting the packet send
// and response times.
bool
SendSpeedTestPacket (uint32_t send_size,
uint32_t recv_size);
bool
SetCurrentThread (uint64_t tid);
bool
SetCurrentThreadForRun (uint64_t tid);
bool
GetQXferAuxvReadSupported ();
bool
GetQXferLibrariesReadSupported ();
bool
GetQXferLibrariesSVR4ReadSupported ();
uint64_t
GetRemoteMaxPacketSize();
bool
GetEchoSupported ();
bool
GetAugmentedLibrariesSVR4ReadSupported ();
bool
GetQXferFeaturesReadSupported ();
LazyBool
SupportsAllocDeallocMemory () // const
{
// Uncomment this to have lldb pretend the debug server doesn't respond to alloc/dealloc memory packets.
// m_supports_alloc_dealloc_memory = lldb_private::eLazyBoolNo;
return m_supports_alloc_dealloc_memory;
}
size_t
GetCurrentThreadIDs (std::vector<lldb::tid_t> &thread_ids,
bool &sequence_mutex_unavailable);
lldb::user_id_t
OpenFile (const FileSpec& file_spec, uint32_t flags, mode_t mode, Error &error);
bool
CloseFile (lldb::user_id_t fd, Error &error);
lldb::user_id_t
GetFileSize (const FileSpec& file_spec);
Error
GetFilePermissions(const FileSpec &file_spec, uint32_t &file_permissions);
Error
SetFilePermissions(const FileSpec &file_spec, uint32_t file_permissions);
uint64_t
ReadFile (lldb::user_id_t fd,
uint64_t offset,
void *dst,
uint64_t dst_len,
Error &error);
uint64_t
WriteFile (lldb::user_id_t fd,
uint64_t offset,
const void* src,
uint64_t src_len,
Error &error);
Error
CreateSymlink(const FileSpec &src,
const FileSpec &dst);
Error
Unlink(const FileSpec &file_spec);
Error
MakeDirectory(const FileSpec &file_spec, uint32_t mode);
bool
GetFileExists (const FileSpec& file_spec);
Error
RunShellCommand(const char *command, // Shouldn't be nullptr
const FileSpec &working_dir, // Pass empty FileSpec to use the current working directory
int *status_ptr, // Pass nullptr if you don't want the process exit status
int *signo_ptr, // Pass nullptr if you don't want the signal that caused the process to exit
std::string *command_output, // Pass nullptr if you don't want the command output
uint32_t timeout_sec); // Timeout in seconds to wait for shell program to finish
bool
CalculateMD5 (const FileSpec& file_spec, uint64_t &high, uint64_t &low);
bool
ReadRegister(lldb::tid_t tid,
uint32_t reg_num, // Must be the eRegisterKindProcessPlugin register number, to be sent to the remote
StringExtractorGDBRemote &response);
bool
ReadAllRegisters (lldb::tid_t tid,
StringExtractorGDBRemote &response);
bool
SaveRegisterState (lldb::tid_t tid, uint32_t &save_id);
bool
RestoreRegisterState (lldb::tid_t tid, uint32_t save_id);
const char *
GetGDBServerProgramName();
uint32_t
GetGDBServerProgramVersion();
bool
AvoidGPackets(ProcessGDBRemote *process);
StructuredData::ObjectSP
GetThreadsInfo();
bool
GetThreadExtendedInfoSupported();
bool
GetLoadedDynamicLibrariesInfosSupported();
bool
GetSharedCacheInfoSupported();
bool
GetModuleInfo (const FileSpec& module_file_spec,
const ArchSpec& arch_spec,
ModuleSpec &module_spec);
bool
ReadExtFeature (const lldb_private::ConstString object,
const lldb_private::ConstString annex,
std::string & out,
lldb_private::Error & err);
void
ServeSymbolLookups(lldb_private::Process *process);
protected:
LazyBool m_supports_not_sending_acks;
LazyBool m_supports_thread_suffix;
LazyBool m_supports_threads_in_stop_reply;
LazyBool m_supports_vCont_all;
LazyBool m_supports_vCont_any;
LazyBool m_supports_vCont_c;
LazyBool m_supports_vCont_C;
LazyBool m_supports_vCont_s;
LazyBool m_supports_vCont_S;
LazyBool m_qHostInfo_is_valid;
LazyBool m_curr_pid_is_valid;
LazyBool m_qProcessInfo_is_valid;
LazyBool m_qGDBServerVersion_is_valid;
LazyBool m_supports_alloc_dealloc_memory;
LazyBool m_supports_memory_region_info;
LazyBool m_supports_watchpoint_support_info;
LazyBool m_supports_detach_stay_stopped;
LazyBool m_watchpoints_trigger_after_instruction;
LazyBool m_attach_or_wait_reply;
LazyBool m_prepare_for_reg_writing_reply;
LazyBool m_supports_p;
LazyBool m_supports_x;
LazyBool m_avoid_g_packets;
LazyBool m_supports_QSaveRegisterState;
LazyBool m_supports_qXfer_auxv_read;
LazyBool m_supports_qXfer_libraries_read;
LazyBool m_supports_qXfer_libraries_svr4_read;
LazyBool m_supports_qXfer_features_read;
LazyBool m_supports_augmented_libraries_svr4_read;
LazyBool m_supports_jThreadExtendedInfo;
LazyBool m_supports_jLoadedDynamicLibrariesInfos;
LazyBool m_supports_jGetSharedCacheInfo;
bool
m_supports_qProcessInfoPID:1,
m_supports_qfProcessInfo:1,
m_supports_qUserName:1,
m_supports_qGroupName:1,
m_supports_qThreadStopInfo:1,
m_supports_z0:1,
m_supports_z1:1,
m_supports_z2:1,
m_supports_z3:1,
m_supports_z4:1,
m_supports_QEnvironment:1,
m_supports_QEnvironmentHexEncoded:1,
m_supports_qSymbol:1,
m_qSymbol_requests_done:1,
m_supports_qModuleInfo:1,
m_supports_jThreadsInfo:1;
lldb::pid_t m_curr_pid;
lldb::tid_t m_curr_tid; // Current gdb remote protocol thread index for all other operations
lldb::tid_t m_curr_tid_run; // Current gdb remote protocol thread index for continue, step, etc
uint32_t m_num_supported_hardware_watchpoints;
ArchSpec m_host_arch;
ArchSpec m_process_arch;
uint32_t m_os_version_major;
uint32_t m_os_version_minor;
uint32_t m_os_version_update;
std::string m_os_build;
std::string m_os_kernel;
std::string m_hostname;
std::string m_gdb_server_name; // from reply to qGDBServerVersion, empty if qGDBServerVersion is not supported
uint32_t m_gdb_server_version; // from reply to qGDBServerVersion, zero if qGDBServerVersion is not supported
uint32_t m_default_packet_timeout;
uint64_t m_max_packet_size; // as returned by qSupported
bool
GetCurrentProcessInfo (bool allow_lazy_pid = true);
bool
GetGDBServerVersion();
// Given the list of compression types that the remote debug stub can support,
// possibly enable compression if we find an encoding we can handle.
void
MaybeEnableCompression (std::vector<std::string> supported_compressions);
bool
DecodeProcessInfoResponse (StringExtractorGDBRemote &response,
ProcessInstanceInfo &process_info);
void
OnRunPacketSent(bool first) override;
private:
DISALLOW_COPY_AND_ASSIGN (GDBRemoteCommunicationClient);
};
} // namespace process_gdb_remote
} // namespace lldb_private
#endif // liblldb_GDBRemoteCommunicationClient_h_