1//===-- GDBRemoteClientBase.h -----------------------------------*- C++ -*-===//
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#ifndef LLDB_SOURCE_PLUGINS_PROCESS_GDB_REMOTE_GDBREMOTECLIENTBASE_H
10#define LLDB_SOURCE_PLUGINS_PROCESS_GDB_REMOTE_GDBREMOTECLIENTBASE_H
11
12#include "GDBRemoteCommunication.h"
13#include "lldb/Utility/Broadcaster.h"
14#include "llvm/ADT/STLFunctionalExtras.h"
15#include "llvm/ADT/StringRef.h"
16#include <chrono>
17#include <condition_variable>
18#include <cstdint>
19#include <mutex>
20
21namespace lldb_private {
22namespace process_gdb_remote {
23
24class GDBRemoteClientBase : public GDBRemoteCommunication, public Broadcaster {
25public:
26 enum {
27 eBroadcastBitRunPacketSent = (1u << 0),
28 };
29
30 struct ContinueDelegate {
31 virtual ~ContinueDelegate();
32 virtual void HandleAsyncStdout(llvm::StringRef out) = 0;
33 virtual void HandleAsyncMisc(llvm::StringRef data) = 0;
34 virtual void HandleStopReply() = 0;
35
36 /// Process asynchronously-received structured data.
37 ///
38 /// \param[in] data
39 /// The complete data packet, expected to start with JSON-async.
40 virtual void HandleAsyncStructuredDataPacket(llvm::StringRef data) = 0;
41 };
42
43 GDBRemoteClientBase(const char *comm_name);
44
45 bool SendAsyncSignal(int signo, std::chrono::seconds interrupt_timeout);
46
47 bool Interrupt(std::chrono::seconds interrupt_timeout);
48
49 lldb::StateType SendContinuePacketAndWaitForResponse(
50 ContinueDelegate &delegate, const UnixSignals &signals,
51 llvm::StringRef payload, std::chrono::seconds interrupt_timeout,
52 StringExtractorGDBRemote &response);
53
54 // If interrupt_timeout == 0 seconds, don't interrupt the target.
55 // Only send the packet if the target is stopped.
56 // If you want to use this mode, use the fact that the timeout is defaulted
57 // so it's clear from the call-site that you are using no-interrupt.
58 // If it is non-zero, interrupt the target if it is running, and
59 // send the packet.
60 // It the target doesn't respond within the given timeout, it returns
61 // ErrorReplyTimeout.
62 PacketResult SendPacketAndWaitForResponse(
63 llvm::StringRef payload, StringExtractorGDBRemote &response,
64 std::chrono::seconds interrupt_timeout = std::chrono::seconds(0));
65
66 PacketResult ReadPacketWithOutputSupport(
67 StringExtractorGDBRemote &response, Timeout<std::micro> timeout,
68 bool sync_on_timeout,
69 llvm::function_ref<void(llvm::StringRef)> output_callback);
70
71 PacketResult SendPacketAndReceiveResponseWithOutputSupport(
72 llvm::StringRef payload, StringExtractorGDBRemote &response,
73 std::chrono::seconds interrupt_timeout,
74 llvm::function_ref<void(llvm::StringRef)> output_callback);
75
76 class Lock {
77 public:
78 // If interrupt_timeout == 0 seconds, only take the lock if the target is
79 // not running. If using this option, use the fact that the
80 // interrupt_timeout is defaulted so it will be obvious at the call site
81 // that you are choosing this mode. If it is non-zero, interrupt the target
82 // if it is running, waiting for the given timeout for the interrupt to
83 // succeed.
84 Lock(GDBRemoteClientBase &comm,
85 std::chrono::seconds interrupt_timeout = std::chrono::seconds(0));
86 ~Lock();
87
88 explicit operator bool() { return m_acquired; }
89
90 // Whether we had to interrupt the continue thread to acquire the
91 // connection.
92 bool DidInterrupt() const { return m_did_interrupt; }
93
94 private:
95 std::unique_lock<std::recursive_mutex> m_async_lock;
96 GDBRemoteClientBase &m_comm;
97 std::chrono::seconds m_interrupt_timeout;
98 bool m_acquired;
99 bool m_did_interrupt;
100
101 void SyncWithContinueThread();
102 };
103
104protected:
105 PacketResult
106 SendPacketAndWaitForResponseNoLock(llvm::StringRef payload,
107 StringExtractorGDBRemote &response);
108
109 virtual void OnRunPacketSent(bool first);
110
111private:
112 /// Variables handling synchronization between the Continue thread and any
113 /// other threads wishing to send packets over the connection. Either the
114 /// continue thread has control over the connection (m_is_running == true) or
115 /// the connection is free for an arbitrary number of other senders to take
116 /// which indicate their interest by incrementing m_async_count.
117 ///
118 /// Semantics of individual states:
119 ///
120 /// - m_continue_packet == false, m_async_count == 0:
121 /// connection is free
122 /// - m_continue_packet == true, m_async_count == 0:
123 /// only continue thread is present
124 /// - m_continue_packet == true, m_async_count > 0:
125 /// continue thread has control, async threads should interrupt it and wait
126 /// for it to set m_continue_packet to false
127 /// - m_continue_packet == false, m_async_count > 0:
128 /// async threads have control, continue thread needs to wait for them to
129 /// finish (m_async_count goes down to 0).
130 /// @{
131 std::mutex m_mutex;
132 std::condition_variable m_cv;
133
134 /// Packet with which to resume after an async interrupt. Can be changed by
135 /// an async thread e.g. to inject a signal.
136 std::string m_continue_packet;
137
138 /// When was the interrupt packet sent. Used to make sure we time out if the
139 /// stub does not respond to interrupt requests.
140 std::chrono::time_point<std::chrono::steady_clock> m_interrupt_endpoint;
141
142 /// Number of threads interested in sending.
143 uint32_t m_async_count;
144
145 /// Whether the continue thread has control.
146 bool m_is_running;
147
148 /// Whether we should resume after a stop.
149 bool m_should_stop;
150 /// @}
151
152 /// This handles the synchronization between individual async threads. For
153 /// now they just use a simple mutex.
154 std::recursive_mutex m_async_mutex;
155
156 bool ShouldStop(const UnixSignals &signals,
157 StringExtractorGDBRemote &response);
158
159 class ContinueLock {
160 public:
161 enum class LockResult { Success, Cancelled, Failed };
162
163 explicit ContinueLock(GDBRemoteClientBase &comm);
164 ~ContinueLock();
165 explicit operator bool() { return m_acquired; }
166
167 LockResult lock();
168
169 void unlock();
170
171 private:
172 GDBRemoteClientBase &m_comm;
173 bool m_acquired;
174 };
175};
176
177} // namespace process_gdb_remote
178} // namespace lldb_private
179
180#endif // LLDB_SOURCE_PLUGINS_PROCESS_GDB_REMOTE_GDBREMOTECLIENTBASE_H
181

source code of lldb/source/Plugins/Process/gdb-remote/GDBRemoteClientBase.h