1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
#ifndef IO_ENGINE_H
#define IO_ENGINE_H
#include "base/exception.hpp"
#include "base/lazy-init.hpp"
#include "base/logger.hpp"
#include "base/shared-object.hpp"
#include <atomic>
#include <exception>
#include <memory>
#include <thread>
#include <utility>
#include <vector>
#include <stdexcept>
#include <boost/exception/all.hpp>
#include <boost/asio/deadline_timer.hpp>
#include <boost/asio/io_context.hpp>
#include <boost/asio/spawn.hpp>
namespace icinga
{
/**
* Scope lock for CPU-bound work done in an I/O thread
*
* @ingroup base
*/
class CpuBoundWork
{
public:
CpuBoundWork(boost::asio::yield_context yc);
CpuBoundWork(const CpuBoundWork&) = delete;
CpuBoundWork(CpuBoundWork&&) = delete;
CpuBoundWork& operator=(const CpuBoundWork&) = delete;
CpuBoundWork& operator=(CpuBoundWork&&) = delete;
~CpuBoundWork();
void Done();
private:
bool m_Done;
};
/**
* Scope break for CPU-bound work done in an I/O thread
*
* @ingroup base
*/
class IoBoundWorkSlot
{
public:
IoBoundWorkSlot(boost::asio::yield_context yc);
IoBoundWorkSlot(const IoBoundWorkSlot&) = delete;
IoBoundWorkSlot(IoBoundWorkSlot&&) = delete;
IoBoundWorkSlot& operator=(const IoBoundWorkSlot&) = delete;
IoBoundWorkSlot& operator=(IoBoundWorkSlot&&) = delete;
~IoBoundWorkSlot();
private:
boost::asio::yield_context yc;
};
/**
* Async I/O engine
*
* @ingroup base
*/
class IoEngine
{
friend CpuBoundWork;
friend IoBoundWorkSlot;
public:
IoEngine(const IoEngine&) = delete;
IoEngine(IoEngine&&) = delete;
IoEngine& operator=(const IoEngine&) = delete;
IoEngine& operator=(IoEngine&&) = delete;
~IoEngine();
static IoEngine& Get();
boost::asio::io_context& GetIoContext();
static inline size_t GetCoroutineStackSize() {
#ifdef _WIN32
// Increase the stack size for Windows coroutines to prevent exception corruption.
// Rationale: Low cost Windows agent only & https://github.com/Icinga/icinga2/issues/7431
return 8 * 1024 * 1024;
#else /* _WIN32 */
// Increase the stack size for Linux/Unix coroutines for many JSON objects on the stack.
// This may help mitigate possible stack overflows. https://github.com/Icinga/icinga2/issues/7532
return 256 * 1024;
//return boost::coroutines::stack_allocator::traits_type::default_size(); // Default 64 KB
#endif /* _WIN32 */
}
template <typename Handler, typename Function>
static void SpawnCoroutine(Handler& h, Function f) {
boost::asio::spawn(h,
[f](boost::asio::yield_context yc) {
try {
f(yc);
} catch (const boost::coroutines::detail::forced_unwind &) {
// Required for proper stack unwinding when coroutines are destroyed.
// https://github.com/boostorg/coroutine/issues/39
throw;
} catch (const std::exception& ex) {
Log(LogCritical, "IoEngine", "Exception in coroutine!");
Log(LogDebug, "IoEngine") << "Exception in coroutine: " << DiagnosticInformation(ex);
} catch (...) {
Log(LogCritical, "IoEngine", "Exception in coroutine!");
}
},
boost::coroutines::attributes(GetCoroutineStackSize()) // Set a pre-defined stack size.
);
}
static inline
void YieldCurrentCoroutine(boost::asio::yield_context yc)
{
Get().m_AlreadyExpiredTimer.async_wait(yc);
}
private:
IoEngine();
void RunEventLoop();
static LazyInit<std::unique_ptr<IoEngine>> m_Instance;
boost::asio::io_context m_IoContext;
boost::asio::executor_work_guard<boost::asio::io_context::executor_type> m_KeepAlive;
std::vector<std::thread> m_Threads;
boost::asio::deadline_timer m_AlreadyExpiredTimer;
std::atomic_int_fast32_t m_CpuBoundSemaphore;
};
class TerminateIoThread : public std::exception
{
};
/**
* Condition variable which doesn't block I/O threads
*
* @ingroup base
*/
class AsioConditionVariable
{
public:
AsioConditionVariable(boost::asio::io_context& io, bool init = false);
void Set();
void Clear();
void Wait(boost::asio::yield_context yc);
private:
boost::asio::deadline_timer m_Timer;
};
/**
* I/O timeout emulator
*
* @ingroup base
*/
class Timeout : public SharedObject
{
public:
DECLARE_PTR_TYPEDEFS(Timeout);
template<class Executor, class TimeoutFromNow, class OnTimeout>
Timeout(boost::asio::io_context& io, Executor& executor, TimeoutFromNow timeoutFromNow, OnTimeout onTimeout)
: m_Timer(io)
{
Ptr keepAlive (this);
m_Cancelled.store(false);
m_Timer.expires_from_now(std::move(timeoutFromNow));
IoEngine::SpawnCoroutine(executor, [this, keepAlive, onTimeout](boost::asio::yield_context yc) {
if (m_Cancelled.load()) {
return;
}
{
boost::system::error_code ec;
m_Timer.async_wait(yc[ec]);
if (ec) {
return;
}
}
if (m_Cancelled.load()) {
return;
}
auto f (onTimeout);
f(std::move(yc));
});
}
void Cancel();
private:
boost::asio::deadline_timer m_Timer;
std::atomic<bool> m_Cancelled;
};
}
#endif /* IO_ENGINE_H */
|
