1//===-- xray_log_interface.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// This file is a part of XRay, a function call tracing system.
10//
11//===----------------------------------------------------------------------===//
12#include "xray/xray_log_interface.h"
13
14#include "sanitizer_common/sanitizer_allocator_internal.h"
15#include "sanitizer_common/sanitizer_atomic.h"
16#include "sanitizer_common/sanitizer_mutex.h"
17#include "xray/xray_interface.h"
18#include "xray_defs.h"
19
20namespace __xray {
21static SpinMutex XRayImplMutex;
22static XRayLogImpl CurrentXRayImpl{.log_init: nullptr, .log_finalize: nullptr, .handle_arg0: nullptr, .flush_log: nullptr};
23static XRayLogImpl *GlobalXRayImpl = nullptr;
24
25// This is the default implementation of a buffer iterator, which always yields
26// a null buffer.
27XRayBuffer NullBufferIterator(XRayBuffer) XRAY_NEVER_INSTRUMENT {
28 return {.Data: nullptr, .Size: 0};
29}
30
31// This is the global function responsible for iterating through given buffers.
32atomic_uintptr_t XRayBufferIterator{
33 .val_dont_use: reinterpret_cast<uintptr_t>(&NullBufferIterator)};
34
35// We use a linked list of Mode to XRayLogImpl mappings. This is a linked list
36// when it should be a map because we're avoiding having to depend on C++
37// standard library data structures at this level of the implementation.
38struct ModeImpl {
39 ModeImpl *Next;
40 const char *Mode;
41 XRayLogImpl Impl;
42};
43
44static ModeImpl SentinelModeImpl{
45 .Next: nullptr, .Mode: nullptr, .Impl: {.log_init: nullptr, .log_finalize: nullptr, .handle_arg0: nullptr, .flush_log: nullptr}};
46static ModeImpl *ModeImpls = &SentinelModeImpl;
47static const ModeImpl *CurrentMode = nullptr;
48
49} // namespace __xray
50
51using namespace __xray;
52
53void __xray_log_set_buffer_iterator(XRayBuffer (*Iterator)(XRayBuffer))
54 XRAY_NEVER_INSTRUMENT {
55 atomic_store(a: &__xray::XRayBufferIterator,
56 v: reinterpret_cast<uintptr_t>(Iterator), mo: memory_order_release);
57}
58
59void __xray_log_remove_buffer_iterator() XRAY_NEVER_INSTRUMENT {
60 __xray_log_set_buffer_iterator(Iterator: &NullBufferIterator);
61}
62
63XRayLogRegisterStatus
64__xray_log_register_mode(const char *Mode,
65 XRayLogImpl Impl) XRAY_NEVER_INSTRUMENT {
66 if (Impl.flush_log == nullptr || Impl.handle_arg0 == nullptr ||
67 Impl.log_finalize == nullptr || Impl.log_init == nullptr)
68 return XRayLogRegisterStatus::XRAY_INCOMPLETE_IMPL;
69
70 SpinMutexLock Guard(&XRayImplMutex);
71 // First, look for whether the mode already has a registered implementation.
72 for (ModeImpl *it = ModeImpls; it != &SentinelModeImpl; it = it->Next) {
73 if (!internal_strcmp(s1: Mode, s2: it->Mode))
74 return XRayLogRegisterStatus::XRAY_DUPLICATE_MODE;
75 }
76 auto *NewModeImpl = static_cast<ModeImpl *>(InternalAlloc(size: sizeof(ModeImpl)));
77 NewModeImpl->Next = ModeImpls;
78 NewModeImpl->Mode = internal_strdup(s: Mode);
79 NewModeImpl->Impl = Impl;
80 ModeImpls = NewModeImpl;
81 return XRayLogRegisterStatus::XRAY_REGISTRATION_OK;
82}
83
84XRayLogRegisterStatus
85__xray_log_select_mode(const char *Mode) XRAY_NEVER_INSTRUMENT {
86 SpinMutexLock Guard(&XRayImplMutex);
87 for (ModeImpl *it = ModeImpls; it != &SentinelModeImpl; it = it->Next) {
88 if (!internal_strcmp(s1: Mode, s2: it->Mode)) {
89 CurrentMode = it;
90 CurrentXRayImpl = it->Impl;
91 GlobalXRayImpl = &CurrentXRayImpl;
92 __xray_set_handler(entry: it->Impl.handle_arg0);
93 return XRayLogRegisterStatus::XRAY_REGISTRATION_OK;
94 }
95 }
96 return XRayLogRegisterStatus::XRAY_MODE_NOT_FOUND;
97}
98
99const char *__xray_log_get_current_mode() XRAY_NEVER_INSTRUMENT {
100 SpinMutexLock Guard(&XRayImplMutex);
101 if (CurrentMode != nullptr)
102 return CurrentMode->Mode;
103 return nullptr;
104}
105
106void __xray_set_log_impl(XRayLogImpl Impl) XRAY_NEVER_INSTRUMENT {
107 if (Impl.log_init == nullptr || Impl.log_finalize == nullptr ||
108 Impl.handle_arg0 == nullptr || Impl.flush_log == nullptr) {
109 SpinMutexLock Guard(&XRayImplMutex);
110 GlobalXRayImpl = nullptr;
111 CurrentMode = nullptr;
112 __xray_remove_handler();
113 __xray_remove_handler_arg1();
114 return;
115 }
116
117 SpinMutexLock Guard(&XRayImplMutex);
118 CurrentXRayImpl = Impl;
119 GlobalXRayImpl = &CurrentXRayImpl;
120 __xray_set_handler(entry: Impl.handle_arg0);
121}
122
123void __xray_remove_log_impl() XRAY_NEVER_INSTRUMENT {
124 SpinMutexLock Guard(&XRayImplMutex);
125 GlobalXRayImpl = nullptr;
126 __xray_remove_handler();
127 __xray_remove_handler_arg1();
128}
129
130XRayLogInitStatus __xray_log_init(size_t BufferSize, size_t MaxBuffers,
131 void *Args,
132 size_t ArgsSize) XRAY_NEVER_INSTRUMENT {
133 SpinMutexLock Guard(&XRayImplMutex);
134 if (!GlobalXRayImpl)
135 return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
136 return GlobalXRayImpl->log_init(BufferSize, MaxBuffers, Args, ArgsSize);
137}
138
139XRayLogInitStatus __xray_log_init_mode(const char *Mode, const char *Config)
140 XRAY_NEVER_INSTRUMENT {
141 SpinMutexLock Guard(&XRayImplMutex);
142 if (!GlobalXRayImpl)
143 return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
144
145 if (Config == nullptr)
146 return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
147
148 // Check first whether the current mode is the same as what we expect.
149 if (CurrentMode == nullptr || internal_strcmp(s1: CurrentMode->Mode, s2: Mode) != 0)
150 return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
151
152 // Here we do some work to coerce the pointer we're provided, so that
153 // the implementations that still take void* pointers can handle the
154 // data provided in the Config argument.
155 return GlobalXRayImpl->log_init(
156 0, 0, const_cast<void *>(static_cast<const void *>(Config)), 0);
157}
158
159XRayLogInitStatus
160__xray_log_init_mode_bin(const char *Mode, const char *Config,
161 size_t ConfigSize) XRAY_NEVER_INSTRUMENT {
162 SpinMutexLock Guard(&XRayImplMutex);
163 if (!GlobalXRayImpl)
164 return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
165
166 if (Config == nullptr)
167 return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
168
169 // Check first whether the current mode is the same as what we expect.
170 if (CurrentMode == nullptr || internal_strcmp(s1: CurrentMode->Mode, s2: Mode) != 0)
171 return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
172
173 // Here we do some work to coerce the pointer we're provided, so that
174 // the implementations that still take void* pointers can handle the
175 // data provided in the Config argument.
176 return GlobalXRayImpl->log_init(
177 0, 0, const_cast<void *>(static_cast<const void *>(Config)), ConfigSize);
178}
179
180XRayLogInitStatus __xray_log_finalize() XRAY_NEVER_INSTRUMENT {
181 SpinMutexLock Guard(&XRayImplMutex);
182 if (!GlobalXRayImpl)
183 return XRayLogInitStatus::XRAY_LOG_UNINITIALIZED;
184 return GlobalXRayImpl->log_finalize();
185}
186
187XRayLogFlushStatus __xray_log_flushLog() XRAY_NEVER_INSTRUMENT {
188 SpinMutexLock Guard(&XRayImplMutex);
189 if (!GlobalXRayImpl)
190 return XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING;
191 return GlobalXRayImpl->flush_log();
192}
193
194XRayLogFlushStatus __xray_log_process_buffers(
195 void (*Processor)(const char *, XRayBuffer)) XRAY_NEVER_INSTRUMENT {
196 // We want to make sure that there will be no changes to the global state for
197 // the log by synchronising on the XRayBufferIteratorMutex.
198 if (!GlobalXRayImpl)
199 return XRayLogFlushStatus::XRAY_LOG_NOT_FLUSHING;
200 auto Iterator = reinterpret_cast<XRayBuffer (*)(XRayBuffer)>(
201 atomic_load(a: &XRayBufferIterator, mo: memory_order_acquire));
202 auto Buffer = (*Iterator)(XRayBuffer{.Data: nullptr, .Size: 0});
203 auto Mode = CurrentMode ? CurrentMode->Mode : nullptr;
204 while (Buffer.Data != nullptr) {
205 (*Processor)(Mode, Buffer);
206 Buffer = (*Iterator)(Buffer);
207 }
208 return XRayLogFlushStatus::XRAY_LOG_FLUSHED;
209}
210