1 //===-- GDBRemoteCommunicationServer.cpp ----------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include <cerrno>
10 
11 #include "lldb/Host/Config.h"
12 
13 #include "GDBRemoteCommunicationServer.h"
14 
15 #include "ProcessGDBRemoteLog.h"
16 #include "lldb/Utility/StreamString.h"
17 #include "lldb/Utility/StringExtractorGDBRemote.h"
18 #include "lldb/Utility/UnimplementedError.h"
19 #include "llvm/Support/JSON.h"
20 #include <cstring>
21 
22 using namespace lldb;
23 using namespace lldb_private;
24 using namespace lldb_private::process_gdb_remote;
25 using namespace llvm;
26 
27 GDBRemoteCommunicationServer::GDBRemoteCommunicationServer(
28     const char *comm_name, const char *listener_name)
29     : GDBRemoteCommunication(comm_name, listener_name), m_exit_now(false) {
30   RegisterPacketHandler(
31       StringExtractorGDBRemote::eServerPacketType_QEnableErrorStrings,
32       [this](StringExtractorGDBRemote packet, Status &error, bool &interrupt,
33              bool &quit) { return this->Handle_QErrorStringEnable(packet); });
34 }
35 
36 GDBRemoteCommunicationServer::~GDBRemoteCommunicationServer() = default;
37 
38 void GDBRemoteCommunicationServer::RegisterPacketHandler(
39     StringExtractorGDBRemote::ServerPacketType packet_type,
40     PacketHandler handler) {
41   m_packet_handlers[packet_type] = std::move(handler);
42 }
43 
44 GDBRemoteCommunication::PacketResult
45 GDBRemoteCommunicationServer::GetPacketAndSendResponse(
46     Timeout<std::micro> timeout, Status &error, bool &interrupt, bool &quit) {
47   StringExtractorGDBRemote packet;
48 
49   PacketResult packet_result = WaitForPacketNoLock(packet, timeout, false);
50   if (packet_result == PacketResult::Success) {
51     const StringExtractorGDBRemote::ServerPacketType packet_type =
52         packet.GetServerPacketType();
53     switch (packet_type) {
54     case StringExtractorGDBRemote::eServerPacketType_nack:
55     case StringExtractorGDBRemote::eServerPacketType_ack:
56       break;
57 
58     case StringExtractorGDBRemote::eServerPacketType_invalid:
59       error.SetErrorString("invalid packet");
60       quit = true;
61       break;
62 
63     case StringExtractorGDBRemote::eServerPacketType_unimplemented:
64       packet_result = SendUnimplementedResponse(packet.GetStringRef().data());
65       break;
66 
67     default:
68       auto handler_it = m_packet_handlers.find(packet_type);
69       if (handler_it == m_packet_handlers.end())
70         packet_result = SendUnimplementedResponse(packet.GetStringRef().data());
71       else
72         packet_result = handler_it->second(packet, error, interrupt, quit);
73       break;
74     }
75   } else {
76     if (!IsConnected()) {
77       error.SetErrorString("lost connection");
78       quit = true;
79     } else {
80       error.SetErrorString("timeout");
81     }
82   }
83 
84   // Check if anything occurred that would force us to want to exit.
85   if (m_exit_now)
86     quit = true;
87 
88   return packet_result;
89 }
90 
91 GDBRemoteCommunication::PacketResult
92 GDBRemoteCommunicationServer::SendUnimplementedResponse(const char *) {
93   // TODO: Log the packet we aren't handling...
94   return SendPacketNoLock("");
95 }
96 
97 GDBRemoteCommunication::PacketResult
98 GDBRemoteCommunicationServer::SendErrorResponse(uint8_t err) {
99   char packet[16];
100   int packet_len = ::snprintf(packet, sizeof(packet), "E%2.2x", err);
101   assert(packet_len < (int)sizeof(packet));
102   return SendPacketNoLock(llvm::StringRef(packet, packet_len));
103 }
104 
105 GDBRemoteCommunication::PacketResult
106 GDBRemoteCommunicationServer::SendErrorResponse(const Status &error) {
107   if (m_send_error_strings) {
108     lldb_private::StreamString packet;
109     packet.Printf("E%2.2x;", static_cast<uint8_t>(error.GetError()));
110     packet.PutStringAsRawHex8(error.AsCString());
111     return SendPacketNoLock(packet.GetString());
112   } else
113     return SendErrorResponse(error.GetError());
114 }
115 
116 GDBRemoteCommunication::PacketResult
117 GDBRemoteCommunicationServer::SendErrorResponse(llvm::Error error) {
118   assert(error);
119   std::unique_ptr<llvm::ErrorInfoBase> EIB;
120   std::unique_ptr<UnimplementedError> UE;
121   llvm::handleAllErrors(
122       std::move(error),
123       [&](std::unique_ptr<UnimplementedError> E) { UE = std::move(E); },
124       [&](std::unique_ptr<llvm::ErrorInfoBase> E) { EIB = std::move(E); });
125 
126   if (EIB)
127     return SendErrorResponse(Status(llvm::Error(std::move(EIB))));
128   return SendUnimplementedResponse("");
129 }
130 
131 GDBRemoteCommunication::PacketResult
132 GDBRemoteCommunicationServer::Handle_QErrorStringEnable(
133     StringExtractorGDBRemote &packet) {
134   m_send_error_strings = true;
135   return SendOKResponse();
136 }
137 
138 GDBRemoteCommunication::PacketResult
139 GDBRemoteCommunicationServer::SendIllFormedResponse(
140     const StringExtractorGDBRemote &failed_packet, const char *message) {
141   Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_PACKETS));
142   LLDB_LOGF(log, "GDBRemoteCommunicationServer::%s: ILLFORMED: '%s' (%s)",
143             __FUNCTION__, failed_packet.GetStringRef().data(),
144             message ? message : "");
145   return SendErrorResponse(0x03);
146 }
147 
148 GDBRemoteCommunication::PacketResult
149 GDBRemoteCommunicationServer::SendOKResponse() {
150   return SendPacketNoLock("OK");
151 }
152 
153 bool GDBRemoteCommunicationServer::HandshakeWithClient() {
154   return GetAck() == PacketResult::Success;
155 }
156 
157 GDBRemoteCommunication::PacketResult
158 GDBRemoteCommunicationServer::SendJSONResponse(const json::Value &value) {
159   std::string json_string;
160   raw_string_ostream os(json_string);
161   os << value;
162   os.flush();
163   StreamGDBRemote escaped_response;
164   escaped_response.PutEscapedBytes(json_string.c_str(), json_string.size());
165   return SendPacketNoLock(escaped_response.GetString());
166 }
167 
168 GDBRemoteCommunication::PacketResult
169 GDBRemoteCommunicationServer::SendJSONResponse(Expected<json::Value> value) {
170   if (!value)
171     return SendErrorResponse(value.takeError());
172   return SendJSONResponse(*value);
173 }
174