1//===-- AppleGetQueuesHandler.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 "AppleGetQueuesHandler.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/FunctionCaller.h"
16#include "lldb/Expression/UtilityFunction.h"
17#include "lldb/Symbol/Symbol.h"
18#include "lldb/Target/ExecutionContext.h"
19#include "lldb/Target/Process.h"
20#include "lldb/Target/Target.h"
21#include "lldb/Target/Thread.h"
22#include "lldb/Utility/ConstString.h"
23#include "lldb/Utility/LLDBLog.h"
24#include "lldb/Utility/Log.h"
25#include "lldb/Utility/StreamString.h"
26
27using namespace lldb;
28using namespace lldb_private;
29
30const char *AppleGetQueuesHandler::g_get_current_queues_function_name =
31 "__lldb_backtrace_recording_get_current_queues";
32const char *AppleGetQueuesHandler::g_get_current_queues_function_code =
33 " \n\
34extern \"C\" \n\
35{ \n\
36 /* \n\
37 * mach defines \n\
38 */ \n\
39 \n\
40 typedef unsigned int uint32_t; \n\
41 typedef unsigned long long uint64_t; \n\
42 typedef uint32_t mach_port_t; \n\
43 typedef mach_port_t vm_map_t; \n\
44 typedef int kern_return_t; \n\
45 typedef uint64_t mach_vm_address_t; \n\
46 typedef uint64_t mach_vm_size_t; \n\
47 \n\
48 mach_port_t mach_task_self (); \n\
49 kern_return_t mach_vm_deallocate (vm_map_t target, mach_vm_address_t address, mach_vm_size_t size); \n\
50 \n\
51 /* \n\
52 * libBacktraceRecording defines \n\
53 */ \n\
54 \n\
55 typedef uint32_t queue_list_scope_t; \n\
56 typedef void *introspection_dispatch_queue_info_t; \n\
57 \n\
58 extern uint64_t __introspection_dispatch_get_queues (queue_list_scope_t scope, \n\
59 introspection_dispatch_queue_info_t *returned_queues_buffer, \n\
60 uint64_t *returned_queues_buffer_size); \n\
61 extern int printf(const char *format, ...); \n\
62 \n\
63 /* \n\
64 * return type define \n\
65 */ \n\
66 \n\
67 struct get_current_queues_return_values \n\
68 { \n\
69 uint64_t queues_buffer_ptr; /* the address of the queues buffer from libBacktraceRecording */ \n\
70 uint64_t queues_buffer_size; /* the size of the queues buffer from libBacktraceRecording */ \n\
71 uint64_t count; /* the number of queues included in the queues buffer */ \n\
72 }; \n\
73 \n\
74 void __lldb_backtrace_recording_get_current_queues \n\
75 (struct get_current_queues_return_values *return_buffer, \n\
76 int debug, \n\
77 void *page_to_free, \n\
78 uint64_t page_to_free_size) \n\
79{ \n\
80 if (debug) \n\
81 printf (\"entering get_current_queues with args %p, %d, 0x%p, 0x%llx\\n\", return_buffer, debug, page_to_free, page_to_free_size); \n\
82 if (page_to_free != 0) \n\
83 { \n\
84 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\
85 } \n\
86 \n\
87 return_buffer->count = __introspection_dispatch_get_queues ( \n\
88 /* QUEUES_WITH_ANY_ITEMS */ 2, \n\
89 (void**)&return_buffer->queues_buffer_ptr, \n\
90 &return_buffer->queues_buffer_size); \n\
91 if (debug) \n\
92 printf(\"result was count %lld\\n\", return_buffer->count); \n\
93} \n\
94} \n\
95";
96
97AppleGetQueuesHandler::AppleGetQueuesHandler(Process *process)
98 : m_process(process), m_get_queues_impl_code_up(),
99 m_get_queues_function_mutex(),
100 m_get_queues_return_buffer_addr(LLDB_INVALID_ADDRESS),
101 m_get_queues_retbuffer_mutex() {}
102
103AppleGetQueuesHandler::~AppleGetQueuesHandler() = default;
104
105void AppleGetQueuesHandler::Detach() {
106
107 if (m_process && m_process->IsAlive() &&
108 m_get_queues_return_buffer_addr != LLDB_INVALID_ADDRESS) {
109 std::unique_lock<std::mutex> lock(m_get_queues_retbuffer_mutex,
110 std::defer_lock);
111 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
112 m_process->DeallocateMemory(ptr: m_get_queues_return_buffer_addr);
113 }
114}
115
116// Construct a CompilerType for the structure that
117// g_get_current_queues_function_code will return by value so we can extract
118// the fields after performing the function call. i.e. we are getting this
119// struct returned to us:
120//
121// struct get_current_queues_return_values
122// {
123// introspection_dispatch_queue_info_t *queues_buffer;
124// uint64_t queues_buffer_size;
125// uint64_t count;
126// };
127
128// Compile our __lldb_backtrace_recording_get_current_queues() function (from
129// the source above in g_get_current_queues_function_code) if we don't find
130// that function in the inferior already with USE_BUILTIN_FUNCTION defined.
131// (e.g. this would be the case for testing.)
132//
133// Insert the __lldb_backtrace_recording_get_current_queues into the inferior
134// process if needed.
135//
136// Write the get_queues_arglist into the inferior's memory space to prepare for
137// the call.
138//
139// Returns the address of the arguments written down in the inferior process,
140// which can be used to make the function call.
141
142lldb::addr_t
143AppleGetQueuesHandler::SetupGetQueuesFunction(Thread &thread,
144 ValueList &get_queues_arglist) {
145 ThreadSP thread_sp(thread.shared_from_this());
146 ExecutionContext exe_ctx(thread_sp);
147
148 Address impl_code_address;
149 DiagnosticManager diagnostics;
150 Log *log = GetLog(mask: LLDBLog::SystemRuntime);
151 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
152
153 FunctionCaller *get_queues_caller = nullptr;
154
155 // Scope for mutex locker:
156 {
157 std::lock_guard<std::mutex> guard(m_get_queues_function_mutex);
158
159 // First stage is to make the ClangUtility to hold our injected function:
160
161 if (!m_get_queues_impl_code_up) {
162 if (g_get_current_queues_function_code != nullptr) {
163 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(
164 expression: g_get_current_queues_function_code,
165 name: g_get_current_queues_function_name, language: eLanguageTypeC, exe_ctx);
166 if (!utility_fn_or_error) {
167 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(),
168 "Failed to create UtilityFunction for queues "
169 "introspection: {0}.");
170 return args_addr;
171 }
172 m_get_queues_impl_code_up = std::move(*utility_fn_or_error);
173 } else {
174 if (log) {
175 LLDB_LOGF(log, "No queues introspection code found.");
176 diagnostics.Dump(log);
177 }
178 return LLDB_INVALID_ADDRESS;
179 }
180 }
181
182 // Next make the runner function for our implementation utility function.
183 TypeSystemClangSP scratch_ts_sp =
184 ScratchTypeSystemClang::GetForTarget(target&: thread.GetProcess()->GetTarget());
185 CompilerType get_queues_return_type =
186 scratch_ts_sp->GetBasicType(type: eBasicTypeVoid).GetPointerType();
187 Status error;
188 get_queues_caller = m_get_queues_impl_code_up->MakeFunctionCaller(
189 return_type: get_queues_return_type, arg_value_list: get_queues_arglist, compilation_thread: thread_sp, error);
190 if (error.Fail() || get_queues_caller == nullptr) {
191 LLDB_LOGF(log,
192 "Could not get function caller for get-queues function: %s.",
193 error.AsCString());
194 return args_addr;
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_queues_caller->WriteFunctionArguments(
206 exe_ctx, args_addr_ref&: args_addr, arg_values&: get_queues_arglist, diagnostic_manager&: diagnostics)) {
207 if (log) {
208 LLDB_LOGF(log, "Error writing get-queues function arguments.");
209 diagnostics.Dump(log);
210 }
211 return args_addr;
212 }
213
214 return args_addr;
215}
216
217AppleGetQueuesHandler::GetQueuesReturnInfo
218AppleGetQueuesHandler::GetCurrentQueues(Thread &thread, addr_t page_to_free,
219 uint64_t page_to_free_size,
220 Status &error) {
221 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(idx: 0);
222 ProcessSP process_sp(thread.CalculateProcess());
223 TargetSP target_sp(thread.CalculateTarget());
224 TypeSystemClangSP scratch_ts_sp =
225 ScratchTypeSystemClang::GetForTarget(target&: *target_sp);
226 Log *log = GetLog(mask: LLDBLog::SystemRuntime);
227
228 GetQueuesReturnInfo return_value;
229 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
230 return_value.queues_buffer_size = 0;
231 return_value.count = 0;
232
233 error.Clear();
234
235 if (!thread.SafeToCallFunctions()) {
236 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64,
237 thread.GetID());
238 error =
239 Status::FromErrorString(str: "Not safe to call functions on this thread.");
240 return return_value;
241 }
242
243 // Set up the arguments for a call to
244
245 // struct get_current_queues_return_values
246 // {
247 // uint64_t queues_buffer_ptr; /* the address of the queues buffer from
248 // libBacktraceRecording */
249 // uint64_t queues_buffer_size; /* the size of the queues buffer from
250 // libBacktraceRecording */
251 // uint64_t count; /* the number of queues included in the
252 // queues buffer */
253 // };
254 //
255 // void
256 // __lldb_backtrace_recording_get_current_queues
257 // (struct
258 // get_current_queues_return_values
259 // *return_buffer,
260 // void *page_to_free,
261 // uint64_t page_to_free_size);
262
263 // Where the return_buffer argument points to a 24 byte region of memory
264 // already allocated by lldb in the inferior process.
265
266 CompilerType clang_void_ptr_type =
267 scratch_ts_sp->GetBasicType(type: eBasicTypeVoid).GetPointerType();
268 Value return_buffer_ptr_value;
269 return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar);
270 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
271
272 CompilerType clang_int_type = scratch_ts_sp->GetBasicType(type: eBasicTypeInt);
273 Value debug_value;
274 debug_value.SetValueType(Value::ValueType::Scalar);
275 debug_value.SetCompilerType(clang_int_type);
276
277 Value page_to_free_value;
278 page_to_free_value.SetValueType(Value::ValueType::Scalar);
279 page_to_free_value.SetCompilerType(clang_void_ptr_type);
280
281 CompilerType clang_uint64_type =
282 scratch_ts_sp->GetBasicType(type: eBasicTypeUnsignedLongLong);
283 Value page_to_free_size_value;
284 page_to_free_size_value.SetValueType(Value::ValueType::Scalar);
285 page_to_free_size_value.SetCompilerType(clang_uint64_type);
286
287 std::lock_guard<std::mutex> guard(m_get_queues_retbuffer_mutex);
288 if (m_get_queues_return_buffer_addr == LLDB_INVALID_ADDRESS) {
289 addr_t bufaddr = process_sp->AllocateMemory(
290 size: 32, permissions: ePermissionsReadable | ePermissionsWritable, error);
291 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
292 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "
293 "current queues func call");
294 return return_value;
295 }
296 m_get_queues_return_buffer_addr = bufaddr;
297 }
298
299 ValueList argument_values;
300
301 return_buffer_ptr_value.GetScalar() = m_get_queues_return_buffer_addr;
302 argument_values.PushValue(value: return_buffer_ptr_value);
303
304 debug_value.GetScalar() = 0;
305 argument_values.PushValue(value: debug_value);
306
307 if (page_to_free != LLDB_INVALID_ADDRESS)
308 page_to_free_value.GetScalar() = page_to_free;
309 else
310 page_to_free_value.GetScalar() = 0;
311 argument_values.PushValue(value: page_to_free_value);
312
313 page_to_free_size_value.GetScalar() = page_to_free_size;
314 argument_values.PushValue(value: page_to_free_size_value);
315
316 addr_t args_addr = SetupGetQueuesFunction(thread, get_queues_arglist&: argument_values);
317
318 if (!m_get_queues_impl_code_up) {
319 error = Status::FromErrorString(
320 str: "Unable to compile __introspection_dispatch_get_queues.");
321 return return_value;
322 }
323
324 FunctionCaller *get_queues_caller =
325 m_get_queues_impl_code_up->GetFunctionCaller();
326
327 if (get_queues_caller == nullptr) {
328 error = Status::FromErrorString(
329 str: "Unable to get caller for call __introspection_dispatch_get_queues");
330 return return_value;
331 }
332
333 DiagnosticManager diagnostics;
334 ExecutionContext exe_ctx;
335 EvaluateExpressionOptions options;
336 options.SetUnwindOnError(true);
337 options.SetIgnoreBreakpoints(true);
338 options.SetStopOthers(true);
339#if __has_feature(address_sanitizer)
340 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
341#else
342 options.SetTimeout(std::chrono::milliseconds(500));
343#endif
344 options.SetTryAllThreads(false);
345 options.SetIsForUtilityExpr(true);
346 thread.CalculateExecutionContext(exe_ctx);
347
348 ExpressionResults func_call_ret;
349 Value results;
350 func_call_ret = get_queues_caller->ExecuteFunction(
351 exe_ctx, args_addr_ptr: &args_addr, options, diagnostic_manager&: diagnostics, results);
352 if (func_call_ret != eExpressionCompleted || !error.Success()) {
353 LLDB_LOGF(log,
354 "Unable to call introspection_get_dispatch_queues(), got "
355 "ExpressionResults %d, error contains %s",
356 func_call_ret, error.AsCString(""));
357 error = Status::FromErrorString(
358 str: "Unable to call introspection_get_dispatch_queues() "
359 "for list of queues");
360 return return_value;
361 }
362
363 return_value.queues_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
364 load_addr: m_get_queues_return_buffer_addr, byte_size: 8, LLDB_INVALID_ADDRESS, error);
365 if (!error.Success() ||
366 return_value.queues_buffer_ptr == LLDB_INVALID_ADDRESS) {
367 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
368 return return_value;
369 }
370
371 return_value.queues_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
372 load_addr: m_get_queues_return_buffer_addr + 8, byte_size: 8, fail_value: 0, error);
373
374 if (!error.Success()) {
375 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
376 return return_value;
377 }
378
379 return_value.count = m_process->ReadUnsignedIntegerFromMemory(
380 load_addr: m_get_queues_return_buffer_addr + 16, byte_size: 8, fail_value: 0, error);
381 if (!error.Success()) {
382 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
383 return return_value;
384 }
385
386 LLDB_LOGF(log,
387 "AppleGetQueuesHandler called "
388 "__introspection_dispatch_get_queues (page_to_free == "
389 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64
390 ", size %" PRId64 ", count = %" PRId64,
391 page_to_free, page_to_free_size, return_value.queues_buffer_ptr,
392 return_value.queues_buffer_size, return_value.count);
393
394 return return_value;
395}
396

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