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

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