1//===-- AppleGetThreadItemInfoHandler.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 "AppleGetThreadItemInfoHandler.h"
10
11#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
12#include "lldb/Core/Module.h"
13#include "lldb/Core/Value.h"
14#include "lldb/Expression/DiagnosticManager.h"
15#include "lldb/Expression/Expression.h"
16#include "lldb/Expression/FunctionCaller.h"
17#include "lldb/Expression/UtilityFunction.h"
18#include "lldb/Symbol/Symbol.h"
19#include "lldb/Target/ExecutionContext.h"
20#include "lldb/Target/Process.h"
21#include "lldb/Target/StackFrame.h"
22#include "lldb/Target/Target.h"
23#include "lldb/Target/Thread.h"
24#include "lldb/Utility/ConstString.h"
25#include "lldb/Utility/LLDBLog.h"
26#include "lldb/Utility/Log.h"
27#include "lldb/Utility/StreamString.h"
28#include "lldb/lldb-private.h"
29
30using namespace lldb;
31using namespace lldb_private;
32
33const char
34 *AppleGetThreadItemInfoHandler::g_get_thread_item_info_function_name =
35 "__lldb_backtrace_recording_get_thread_item_info";
36const char
37 *AppleGetThreadItemInfoHandler::g_get_thread_item_info_function_code =
38 " \n\
39extern \"C\" \n\
40{ \n\
41 /* \n\
42 * mach defines \n\
43 */ \n\
44 \n\
45 typedef unsigned int uint32_t; \n\
46 typedef unsigned long long uint64_t; \n\
47 typedef uint32_t mach_port_t; \n\
48 typedef mach_port_t vm_map_t; \n\
49 typedef int kern_return_t; \n\
50 typedef uint64_t mach_vm_address_t; \n\
51 typedef uint64_t mach_vm_size_t; \n\
52 \n\
53 mach_port_t mach_task_self (); \n\
54 kern_return_t mach_vm_deallocate (vm_map_t target, mach_vm_address_t address, mach_vm_size_t size); \n\
55 \n\
56 typedef void *pthread_t; \n\
57 extern int printf(const char *format, ...); \n\
58 extern pthread_t pthread_self(void); \n\
59 \n\
60 /* \n\
61 * libBacktraceRecording defines \n\
62 */ \n\
63 \n\
64 typedef uint32_t queue_list_scope_t; \n\
65 typedef void *dispatch_queue_t; \n\
66 typedef void *introspection_dispatch_queue_info_t; \n\
67 typedef void *introspection_dispatch_item_info_ref; \n\
68 \n\
69 extern void __introspection_dispatch_thread_get_item_info (uint64_t thread_id, \n\
70 introspection_dispatch_item_info_ref *returned_queues_buffer, \n\
71 uint64_t *returned_queues_buffer_size); \n\
72 \n\
73 /* \n\
74 * return type define \n\
75 */ \n\
76 \n\
77 struct get_thread_item_info_return_values \n\
78 { \n\
79 uint64_t item_info_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\
80 uint64_t item_info_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\
81 }; \n\
82 \n\
83 void __lldb_backtrace_recording_get_thread_item_info \n\
84 (struct get_thread_item_info_return_values *return_buffer, \n\
85 int debug, \n\
86 uint64_t thread_id, \n\
87 void *page_to_free, \n\
88 uint64_t page_to_free_size) \n\
89{ \n\
90 void *pthread_id = pthread_self (); \n\
91 if (debug) \n\
92 printf (\"entering get_thread_item_info with args return_buffer == %p, debug == %d, thread id == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, (uint64_t) thread_id, page_to_free, page_to_free_size); \n\
93 if (page_to_free != 0) \n\
94 { \n\
95 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\
96 } \n\
97 \n\
98 __introspection_dispatch_thread_get_item_info (thread_id, \n\
99 (void**)&return_buffer->item_info_buffer_ptr, \n\
100 &return_buffer->item_info_buffer_size); \n\
101} \n\
102} \n\
103";
104
105AppleGetThreadItemInfoHandler::AppleGetThreadItemInfoHandler(Process *process)
106 : m_process(process), m_get_thread_item_info_impl_code(),
107 m_get_thread_item_info_function_mutex(),
108 m_get_thread_item_info_return_buffer_addr(LLDB_INVALID_ADDRESS),
109 m_get_thread_item_info_retbuffer_mutex() {}
110
111AppleGetThreadItemInfoHandler::~AppleGetThreadItemInfoHandler() = default;
112
113void AppleGetThreadItemInfoHandler::Detach() {
114
115 if (m_process && m_process->IsAlive() &&
116 m_get_thread_item_info_return_buffer_addr != LLDB_INVALID_ADDRESS) {
117 std::unique_lock<std::mutex> lock(m_get_thread_item_info_retbuffer_mutex,
118 std::defer_lock);
119 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
120 m_process->DeallocateMemory(ptr: m_get_thread_item_info_return_buffer_addr);
121 }
122}
123
124// Compile our __lldb_backtrace_recording_get_thread_item_info() function (from
125// the source above in g_get_thread_item_info_function_code) if we don't find
126// that function in the inferior already with USE_BUILTIN_FUNCTION defined.
127// (e.g. this would be the case for testing.)
128//
129// Insert the __lldb_backtrace_recording_get_thread_item_info into the inferior
130// process if needed.
131//
132// Write the get_thread_item_info_arglist into the inferior's memory space to
133// prepare for the call.
134//
135// Returns the address of the arguments written down in the inferior process,
136// which can be used to make the function call.
137
138lldb::addr_t AppleGetThreadItemInfoHandler::SetupGetThreadItemInfoFunction(
139 Thread &thread, ValueList &get_thread_item_info_arglist) {
140 ThreadSP thread_sp(thread.shared_from_this());
141 ExecutionContext exe_ctx(thread_sp);
142 Address impl_code_address;
143 DiagnosticManager diagnostics;
144 Log *log = GetLog(mask: LLDBLog::SystemRuntime);
145 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
146 FunctionCaller *get_thread_item_info_caller = nullptr;
147
148 // Scope for mutex locker:
149 {
150 std::lock_guard<std::mutex> guard(m_get_thread_item_info_function_mutex);
151
152 // First stage is to make the ClangUtility to hold our injected function:
153
154 if (!m_get_thread_item_info_impl_code) {
155 Status error;
156 if (g_get_thread_item_info_function_code != nullptr) {
157 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(
158 expression: g_get_thread_item_info_function_code,
159 name: g_get_thread_item_info_function_name, language: eLanguageTypeC, exe_ctx);
160 if (!utility_fn_or_error) {
161 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(),
162 "Failed to get UtilityFunction for "
163 "get-thread-item-info introspection: {0}.");
164 return args_addr;
165 }
166 m_get_thread_item_info_impl_code = std::move(*utility_fn_or_error);
167 } else {
168 LLDB_LOGF(log, "No get-thread-item-info introspection code found.");
169 return LLDB_INVALID_ADDRESS;
170 }
171
172 // Also make the FunctionCaller for this UtilityFunction:
173
174 TypeSystemClangSP scratch_ts_sp = ScratchTypeSystemClang::GetForTarget(
175 target&: thread.GetProcess()->GetTarget());
176 CompilerType get_thread_item_info_return_type =
177 scratch_ts_sp->GetBasicType(type: eBasicTypeVoid).GetPointerType();
178
179 get_thread_item_info_caller =
180 m_get_thread_item_info_impl_code->MakeFunctionCaller(
181 return_type: get_thread_item_info_return_type, arg_value_list: get_thread_item_info_arglist,
182 compilation_thread: thread_sp, error);
183 if (error.Fail() || get_thread_item_info_caller == nullptr) {
184 LLDB_LOGF(log,
185 "Failed to install get-thread-item-info introspection "
186 "caller: %s.",
187 error.AsCString());
188 m_get_thread_item_info_impl_code.reset();
189 return args_addr;
190 }
191
192 } else {
193 get_thread_item_info_caller =
194 m_get_thread_item_info_impl_code->GetFunctionCaller();
195 }
196 }
197
198 diagnostics.Clear();
199
200 // Now write down the argument values for this particular call. This looks
201 // like it might be a race condition if other threads were calling into here,
202 // but actually it isn't because we allocate a new args structure for this
203 // call by passing args_addr = LLDB_INVALID_ADDRESS...
204
205 if (!get_thread_item_info_caller->WriteFunctionArguments(
206 exe_ctx, args_addr_ref&: args_addr, arg_values&: get_thread_item_info_arglist, diagnostic_manager&: diagnostics)) {
207 if (log) {
208 LLDB_LOGF(log, "Error writing get-thread-item-info function arguments");
209 diagnostics.Dump(log);
210 }
211 return args_addr;
212 }
213
214 return args_addr;
215}
216
217AppleGetThreadItemInfoHandler::GetThreadItemInfoReturnInfo
218AppleGetThreadItemInfoHandler::GetThreadItemInfo(Thread &thread,
219 lldb::tid_t thread_id,
220 addr_t page_to_free,
221 uint64_t page_to_free_size,
222 Status &error) {
223 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(idx: 0);
224 ProcessSP process_sp(thread.CalculateProcess());
225 TargetSP target_sp(thread.CalculateTarget());
226 TypeSystemClangSP scratch_ts_sp =
227 ScratchTypeSystemClang::GetForTarget(target&: *target_sp);
228 Log *log = GetLog(mask: LLDBLog::SystemRuntime);
229
230 GetThreadItemInfoReturnInfo return_value;
231 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
232 return_value.item_buffer_size = 0;
233
234 error.Clear();
235
236 if (!thread.SafeToCallFunctions()) {
237 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64,
238 thread.GetID());
239 error =
240 Status::FromErrorString(str: "Not safe to call functions on this thread.");
241 return return_value;
242 }
243
244 // Set up the arguments for a call to
245
246 // struct get_thread_item_info_return_values {
247 // uint64_t item_info_buffer_ptr; /* the address of the items buffer
248 // from libBacktraceRecording */
249 // uint64_t item_info_buffer_size; /* the size of the items buffer from
250 // libBacktraceRecording */
251 // };
252 //
253 // void __lldb_backtrace_recording_get_thread_item_info
254 // (struct
255 // get_thread_item_info_return_values
256 // *return_buffer,
257 // int debug,
258 // void *page_to_free,
259 // uint64_t page_to_free_size)
260
261 // Where the return_buffer argument points to a 24 byte region of memory
262 // already allocated by lldb in the inferior process.
263
264 CompilerType clang_void_ptr_type =
265 scratch_ts_sp->GetBasicType(type: eBasicTypeVoid).GetPointerType();
266 Value return_buffer_ptr_value;
267 return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar);
268 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
269
270 CompilerType clang_int_type = scratch_ts_sp->GetBasicType(type: eBasicTypeInt);
271 Value debug_value;
272 debug_value.SetValueType(Value::ValueType::Scalar);
273 debug_value.SetCompilerType(clang_int_type);
274
275 CompilerType clang_uint64_type =
276 scratch_ts_sp->GetBasicType(type: eBasicTypeUnsignedLongLong);
277 Value thread_id_value;
278 thread_id_value.SetValueType(Value::ValueType::Scalar);
279 thread_id_value.SetCompilerType(clang_uint64_type);
280
281 Value page_to_free_value;
282 page_to_free_value.SetValueType(Value::ValueType::Scalar);
283 page_to_free_value.SetCompilerType(clang_void_ptr_type);
284
285 Value page_to_free_size_value;
286 page_to_free_size_value.SetValueType(Value::ValueType::Scalar);
287 page_to_free_size_value.SetCompilerType(clang_uint64_type);
288
289 std::lock_guard<std::mutex> guard(m_get_thread_item_info_retbuffer_mutex);
290 if (m_get_thread_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS) {
291 addr_t bufaddr = process_sp->AllocateMemory(
292 size: 32, permissions: ePermissionsReadable | ePermissionsWritable, error);
293 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
294 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "
295 "current queues func call");
296 return return_value;
297 }
298 m_get_thread_item_info_return_buffer_addr = bufaddr;
299 }
300
301 ValueList argument_values;
302
303 return_buffer_ptr_value.GetScalar() =
304 m_get_thread_item_info_return_buffer_addr;
305 argument_values.PushValue(value: return_buffer_ptr_value);
306
307 debug_value.GetScalar() = 0;
308 argument_values.PushValue(value: debug_value);
309
310 thread_id_value.GetScalar() = thread_id;
311 argument_values.PushValue(value: thread_id_value);
312
313 if (page_to_free != LLDB_INVALID_ADDRESS)
314 page_to_free_value.GetScalar() = page_to_free;
315 else
316 page_to_free_value.GetScalar() = 0;
317 argument_values.PushValue(value: page_to_free_value);
318
319 page_to_free_size_value.GetScalar() = page_to_free_size;
320 argument_values.PushValue(value: page_to_free_size_value);
321
322 addr_t args_addr = SetupGetThreadItemInfoFunction(thread, get_thread_item_info_arglist&: argument_values);
323
324 DiagnosticManager diagnostics;
325 ExecutionContext exe_ctx;
326 EvaluateExpressionOptions options;
327 FunctionCaller *get_thread_item_info_caller = nullptr;
328
329 options.SetUnwindOnError(true);
330 options.SetIgnoreBreakpoints(true);
331 options.SetStopOthers(true);
332#if __has_feature(address_sanitizer)
333 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
334#else
335 options.SetTimeout(std::chrono::milliseconds(500));
336#endif
337 options.SetTryAllThreads(false);
338 options.SetIsForUtilityExpr(true);
339 thread.CalculateExecutionContext(exe_ctx);
340
341 if (!m_get_thread_item_info_impl_code) {
342 error = Status::FromErrorString(
343 str: "Unable to compile function to call "
344 "__introspection_dispatch_thread_get_item_info");
345 return return_value;
346 }
347
348 get_thread_item_info_caller =
349 m_get_thread_item_info_impl_code->GetFunctionCaller();
350
351 if (!get_thread_item_info_caller) {
352 error = Status::FromErrorString(
353 str: "Unable to compile function caller for "
354 "__introspection_dispatch_thread_get_item_info");
355 return return_value;
356 }
357
358 ExpressionResults func_call_ret;
359 Value results;
360 func_call_ret = get_thread_item_info_caller->ExecuteFunction(
361 exe_ctx, args_addr_ptr: &args_addr, options, diagnostic_manager&: diagnostics, results);
362 if (func_call_ret != eExpressionCompleted || !error.Success()) {
363 LLDB_LOGF(log,
364 "Unable to call "
365 "__introspection_dispatch_thread_get_item_info(), got "
366 "ExpressionResults %d, error contains %s",
367 func_call_ret, error.AsCString(""));
368 error = Status::FromErrorString(
369 str: "Unable to call "
370 "__introspection_dispatch_thread_get_item_info() for "
371 "list of queues");
372 return return_value;
373 }
374
375 return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
376 load_addr: m_get_thread_item_info_return_buffer_addr, byte_size: 8, LLDB_INVALID_ADDRESS,
377 error);
378 if (!error.Success() ||
379 return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS) {
380 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
381 return return_value;
382 }
383
384 return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
385 load_addr: m_get_thread_item_info_return_buffer_addr + 8, byte_size: 8, fail_value: 0, error);
386
387 if (!error.Success()) {
388 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
389 return return_value;
390 }
391
392 LLDB_LOGF(log,
393 "AppleGetThreadItemInfoHandler called "
394 "__introspection_dispatch_thread_get_item_info (page_to_free "
395 "== 0x%" PRIx64 ", size = %" PRId64
396 "), returned page is at 0x%" PRIx64 ", size %" PRId64,
397 page_to_free, page_to_free_size, return_value.item_buffer_ptr,
398 return_value.item_buffer_size);
399
400 return return_value;
401}
402

source code of lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetThreadItemInfoHandler.cpp