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     : GDBRemoteCommunication(), m_exit_now(false) {
29   RegisterPacketHandler(
30       StringExtractorGDBRemote::eServerPacketType_QEnableErrorStrings,
31       [this](StringExtractorGDBRemote packet, Status &error, bool &interrupt,
32              bool &quit) { return this->Handle_QErrorStringEnable(packet); });
33 }
34 
35 GDBRemoteCommunicationServer::~GDBRemoteCommunicationServer() = default;
36 
37 void GDBRemoteCommunicationServer::RegisterPacketHandler(
38     StringExtractorGDBRemote::ServerPacketType packet_type,
39     PacketHandler handler) {
40   m_packet_handlers[packet_type] = std::move(handler);
41 }
42 
43 GDBRemoteCommunication::PacketResult
44 GDBRemoteCommunicationServer::GetPacketAndSendResponse(
45     Timeout<std::micro> timeout, Status &error, bool &interrupt, bool &quit) {
46   StringExtractorGDBRemote packet;
47 
48   PacketResult packet_result = ReadPacket(packet, timeout, false);
49   if (packet_result == PacketResult::Success) {
50     const StringExtractorGDBRemote::ServerPacketType packet_type =
51         packet.GetServerPacketType();
52     switch (packet_type) {
53     case StringExtractorGDBRemote::eServerPacketType_nack:
54     case StringExtractorGDBRemote::eServerPacketType_ack:
55       break;
56 
57     case StringExtractorGDBRemote::eServerPacketType_invalid:
58       error.SetErrorString("invalid packet");
59       quit = true;
60       break;
61 
62     case StringExtractorGDBRemote::eServerPacketType_unimplemented:
63       packet_result = SendUnimplementedResponse(packet.GetStringRef().data());
64       break;
65 
66     default:
67       auto handler_it = m_packet_handlers.find(packet_type);
68       if (handler_it == m_packet_handlers.end())
69         packet_result = SendUnimplementedResponse(packet.GetStringRef().data());
70       else
71         packet_result = handler_it->second(packet, error, interrupt, quit);
72       break;
73     }
74   } else {
75     if (!IsConnected()) {
76       error.SetErrorString("lost connection");
77       quit = true;
78     } else {
79       error.SetErrorString("timeout");
80     }
81   }
82 
83   // Check if anything occurred that would force us to want to exit.
84   if (m_exit_now)
85     quit = true;
86 
87   return packet_result;
88 }
89 
90 GDBRemoteCommunication::PacketResult
91 GDBRemoteCommunicationServer::SendUnimplementedResponse(const char *) {
92   // TODO: Log the packet we aren't handling...
93   return SendPacketNoLock("");
94 }
95 
96 GDBRemoteCommunication::PacketResult
97 GDBRemoteCommunicationServer::SendErrorResponse(uint8_t err) {
98   char packet[16];
99   int packet_len = ::snprintf(packet, sizeof(packet), "E%2.2x", err);
100   assert(packet_len < (int)sizeof(packet));
101   return SendPacketNoLock(llvm::StringRef(packet, packet_len));
102 }
103 
104 GDBRemoteCommunication::PacketResult
105 GDBRemoteCommunicationServer::SendErrorResponse(const Status &error) {
106   if (m_send_error_strings) {
107     lldb_private::StreamString packet;
108     packet.Printf("E%2.2x;", static_cast<uint8_t>(error.GetError()));
109     packet.PutStringAsRawHex8(error.AsCString());
110     return SendPacketNoLock(packet.GetString());
111   } else
112     return SendErrorResponse(error.GetError());
113 }
114 
115 GDBRemoteCommunication::PacketResult
116 GDBRemoteCommunicationServer::SendErrorResponse(llvm::Error error) {
117   assert(error);
118   std::unique_ptr<llvm::ErrorInfoBase> EIB;
119   std::unique_ptr<UnimplementedError> UE;
120   llvm::handleAllErrors(
121       std::move(error),
122       [&](std::unique_ptr<UnimplementedError> E) { UE = std::move(E); },
123       [&](std::unique_ptr<llvm::ErrorInfoBase> E) { EIB = std::move(E); });
124 
125   if (EIB)
126     return SendErrorResponse(Status(llvm::Error(std::move(EIB))));
127   return SendUnimplementedResponse("");
128 }
129 
130 GDBRemoteCommunication::PacketResult
131 GDBRemoteCommunicationServer::Handle_QErrorStringEnable(
132     StringExtractorGDBRemote &packet) {
133   m_send_error_strings = true;
134   return SendOKResponse();
135 }
136 
137 GDBRemoteCommunication::PacketResult
138 GDBRemoteCommunicationServer::SendIllFormedResponse(
139     const StringExtractorGDBRemote &failed_packet, const char *message) {
140   Log *log = GetLog(GDBRLog::Packets);
141   LLDB_LOGF(log, "GDBRemoteCommunicationServer::%s: ILLFORMED: '%s' (%s)",
142             __FUNCTION__, failed_packet.GetStringRef().data(),
143             message ? message : "");
144   return SendErrorResponse(0x03);
145 }
146 
147 GDBRemoteCommunication::PacketResult
148 GDBRemoteCommunicationServer::SendOKResponse() {
149   return SendPacketNoLock("OK");
150 }
151 
152 GDBRemoteCommunication::PacketResult
153 GDBRemoteCommunicationServer::SendJSONResponse(const json::Value &value) {
154   std::string json_string;
155   raw_string_ostream os(json_string);
156   os << value;
157   os.flush();
158   StreamGDBRemote escaped_response;
159   escaped_response.PutEscapedBytes(json_string.c_str(), json_string.size());
160   return SendPacketNoLock(escaped_response.GetString());
161 }
162 
163 GDBRemoteCommunication::PacketResult
164 GDBRemoteCommunicationServer::SendJSONResponse(Expected<json::Value> value) {
165   if (!value)
166     return SendErrorResponse(value.takeError());
167   return SendJSONResponse(*value);
168 }
169