1//===-- AppleGetItemInfoHandler.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 "AppleGetItemInfoHandler.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 *AppleGetItemInfoHandler::g_get_item_info_function_name =
31 "__lldb_backtrace_recording_get_item_info";
32const char *AppleGetItemInfoHandler::g_get_item_info_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 *dispatch_queue_t; \n\
57 typedef void *introspection_dispatch_queue_info_t; \n\
58 typedef void *introspection_dispatch_item_info_ref; \n\
59 \n\
60 extern uint64_t __introspection_dispatch_queue_item_get_info (introspection_dispatch_item_info_ref item_info_ref, \n\
61 introspection_dispatch_item_info_ref *returned_queues_buffer, \n\
62 uint64_t *returned_queues_buffer_size); \n\
63 extern int printf(const char *format, ...); \n\
64 \n\
65 /* \n\
66 * return type define \n\
67 */ \n\
68 \n\
69 struct get_item_info_return_values \n\
70 { \n\
71 uint64_t item_info_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\
72 uint64_t item_info_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\
73 }; \n\
74 \n\
75 void __lldb_backtrace_recording_get_item_info \n\
76 (struct get_item_info_return_values *return_buffer, \n\
77 int debug, \n\
78 uint64_t /* introspection_dispatch_item_info_ref item_info_ref */ item, \n\
79 void *page_to_free, \n\
80 uint64_t page_to_free_size) \n\
81{ \n\
82 if (debug) \n\
83 printf (\"entering get_item_info with args return_buffer == %p, debug == %d, item == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, item, page_to_free, page_to_free_size); \n\
84 if (page_to_free != 0) \n\
85 { \n\
86 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\
87 } \n\
88 \n\
89 __introspection_dispatch_queue_item_get_info ((void*) item, \n\
90 (void**)&return_buffer->item_info_buffer_ptr, \n\
91 &return_buffer->item_info_buffer_size); \n\
92} \n\
93} \n\
94";
95
96AppleGetItemInfoHandler::AppleGetItemInfoHandler(Process *process)
97 : m_process(process), m_get_item_info_impl_code(),
98 m_get_item_info_function_mutex(),
99 m_get_item_info_return_buffer_addr(LLDB_INVALID_ADDRESS),
100 m_get_item_info_retbuffer_mutex() {}
101
102AppleGetItemInfoHandler::~AppleGetItemInfoHandler() = default;
103
104void AppleGetItemInfoHandler::Detach() {
105
106 if (m_process && m_process->IsAlive() &&
107 m_get_item_info_return_buffer_addr != LLDB_INVALID_ADDRESS) {
108 std::unique_lock<std::mutex> lock(m_get_item_info_retbuffer_mutex,
109 std::defer_lock);
110 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
111 m_process->DeallocateMemory(ptr: m_get_item_info_return_buffer_addr);
112 }
113}
114
115// Compile our __lldb_backtrace_recording_get_item_info() function (from the
116// source above in g_get_item_info_function_code) if we don't find that
117// function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g.
118// this would be the case for testing.)
119//
120// Insert the __lldb_backtrace_recording_get_item_info into the inferior
121// process if needed.
122//
123// Write the get_item_info_arglist into the inferior's memory space to prepare
124// for the call.
125//
126// Returns the address of the arguments written down in the inferior process,
127// which can be used to make the function call.
128
129lldb::addr_t AppleGetItemInfoHandler::SetupGetItemInfoFunction(
130 Thread &thread, ValueList &get_item_info_arglist) {
131 ExecutionContext exe_ctx(thread.shared_from_this());
132 DiagnosticManager diagnostics;
133 Log *log = GetLog(mask: LLDBLog::SystemRuntime);
134 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
135 FunctionCaller *get_item_info_caller = nullptr;
136
137 // Scope for mutex locker:
138 {
139 std::lock_guard<std::mutex> guard(m_get_item_info_function_mutex);
140
141 // First stage is to make the UtilityFunction to hold our injected
142 // function:
143
144 if (!m_get_item_info_impl_code) {
145 if (g_get_item_info_function_code != nullptr) {
146 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(
147 expression: g_get_item_info_function_code, name: g_get_item_info_function_name,
148 language: eLanguageTypeObjC, exe_ctx);
149 if (!utility_fn_or_error) {
150 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(),
151 "Failed to create utility function: {0}");
152 }
153 m_get_item_info_impl_code = std::move(*utility_fn_or_error);
154 } else {
155 LLDB_LOGF(log, "No get-item-info introspection code found.");
156 return LLDB_INVALID_ADDRESS;
157 }
158
159 // Next make the runner function for our implementation utility function.
160 auto type_system_or_err =
161 thread.GetProcess()->GetTarget().GetScratchTypeSystemForLanguage(
162 language: eLanguageTypeC);
163 if (auto err = type_system_or_err.takeError()) {
164 LLDB_LOG_ERROR(log, std::move(err),
165 "Error inserting get-item-info function: {0}");
166 return args_addr;
167 }
168 auto ts = *type_system_or_err;
169 if (!ts)
170 return args_addr;
171
172 CompilerType get_item_info_return_type =
173 ts->GetBasicTypeFromAST(basic_type: eBasicTypeVoid)
174 .GetPointerType();
175
176 Status error;
177 get_item_info_caller = m_get_item_info_impl_code->MakeFunctionCaller(
178 return_type: get_item_info_return_type, arg_value_list: get_item_info_arglist,
179 compilation_thread: thread.shared_from_this(), error);
180 if (error.Fail() || get_item_info_caller == nullptr) {
181 LLDB_LOGF(log, "Error inserting get-item-info function: \"%s\".",
182 error.AsCString());
183 return args_addr;
184 }
185 } else {
186 // If it's already made, then we can just retrieve the caller:
187 get_item_info_caller = m_get_item_info_impl_code->GetFunctionCaller();
188 if (!get_item_info_caller) {
189 LLDB_LOGF(log, "Failed to get get-item-info introspection caller.");
190 m_get_item_info_impl_code.reset();
191 return args_addr;
192 }
193 }
194 }
195
196 diagnostics.Clear();
197
198 // Now write down the argument values for this particular call. This looks
199 // like it might be a race condition if other threads were calling into here,
200 // but actually it isn't because we allocate a new args structure for this
201 // call by passing args_addr = LLDB_INVALID_ADDRESS...
202
203 if (!get_item_info_caller->WriteFunctionArguments(
204 exe_ctx, args_addr_ref&: args_addr, arg_values&: get_item_info_arglist, diagnostic_manager&: diagnostics)) {
205 if (log) {
206 LLDB_LOGF(log, "Error writing get-item-info function arguments.");
207 diagnostics.Dump(log);
208 }
209
210 return args_addr;
211 }
212
213 return args_addr;
214}
215
216AppleGetItemInfoHandler::GetItemInfoReturnInfo
217AppleGetItemInfoHandler::GetItemInfo(Thread &thread, uint64_t item,
218 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 GetItemInfoReturnInfo return_value;
229 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
230 return_value.item_buffer_size = 0;
231
232 error.Clear();
233
234 if (!thread.SafeToCallFunctions()) {
235 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64,
236 thread.GetID());
237 error.SetErrorString("Not safe to call functions on this thread.");
238 return return_value;
239 }
240
241 // Set up the arguments for a call to
242
243 // struct get_item_info_return_values
244 // {
245 // uint64_t item_info_buffer_ptr; /* the address of the items buffer
246 // from libBacktraceRecording */
247 // uint64_t item_info_buffer_size; /* the size of the items buffer from
248 // libBacktraceRecording */
249 // };
250 //
251 // void __lldb_backtrace_recording_get_item_info
252 // (struct
253 // get_item_info_return_values
254 // *return_buffer,
255 // int debug,
256 // uint64_t item,
257 // void *page_to_free,
258 // uint64_t page_to_free_size)
259
260 // Where the return_buffer argument points to a 24 byte region of memory
261 // already allocated by lldb in the inferior process.
262
263 CompilerType clang_void_ptr_type =
264 scratch_ts_sp->GetBasicType(type: eBasicTypeVoid).GetPointerType();
265 Value return_buffer_ptr_value;
266 return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar);
267 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
268
269 CompilerType clang_int_type = scratch_ts_sp->GetBasicType(type: eBasicTypeInt);
270 Value debug_value;
271 debug_value.SetValueType(Value::ValueType::Scalar);
272 debug_value.SetCompilerType(clang_int_type);
273
274 CompilerType clang_uint64_type =
275 scratch_ts_sp->GetBasicType(type: eBasicTypeUnsignedLongLong);
276 Value item_value;
277 item_value.SetValueType(Value::ValueType::Scalar);
278 item_value.SetCompilerType(clang_uint64_type);
279
280 Value page_to_free_value;
281 page_to_free_value.SetValueType(Value::ValueType::Scalar);
282 page_to_free_value.SetCompilerType(clang_void_ptr_type);
283
284 Value page_to_free_size_value;
285 page_to_free_size_value.SetValueType(Value::ValueType::Scalar);
286 page_to_free_size_value.SetCompilerType(clang_uint64_type);
287
288 std::lock_guard<std::mutex> guard(m_get_item_info_retbuffer_mutex);
289 if (m_get_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS) {
290 addr_t bufaddr = process_sp->AllocateMemory(
291 size: 32, permissions: ePermissionsReadable | ePermissionsWritable, error);
292 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
293 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "
294 "current queues func call");
295 return return_value;
296 }
297 m_get_item_info_return_buffer_addr = bufaddr;
298 }
299
300 ValueList argument_values;
301
302 return_buffer_ptr_value.GetScalar() = m_get_item_info_return_buffer_addr;
303 argument_values.PushValue(value: return_buffer_ptr_value);
304
305 debug_value.GetScalar() = 0;
306 argument_values.PushValue(value: debug_value);
307
308 item_value.GetScalar() = item;
309 argument_values.PushValue(value: item_value);
310
311 if (page_to_free != LLDB_INVALID_ADDRESS)
312 page_to_free_value.GetScalar() = page_to_free;
313 else
314 page_to_free_value.GetScalar() = 0;
315 argument_values.PushValue(value: page_to_free_value);
316
317 page_to_free_size_value.GetScalar() = page_to_free_size;
318 argument_values.PushValue(value: page_to_free_size_value);
319
320 addr_t args_addr = SetupGetItemInfoFunction(thread, get_item_info_arglist&: argument_values);
321
322 DiagnosticManager diagnostics;
323 ExecutionContext exe_ctx;
324 EvaluateExpressionOptions options;
325 options.SetUnwindOnError(true);
326 options.SetIgnoreBreakpoints(true);
327 options.SetStopOthers(true);
328#if __has_feature(address_sanitizer)
329 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
330#else
331 options.SetTimeout(std::chrono::milliseconds(500));
332#endif
333 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
334 options.SetTryAllThreads(false);
335 options.SetIsForUtilityExpr(true);
336 thread.CalculateExecutionContext(exe_ctx);
337
338 if (!m_get_item_info_impl_code) {
339 error.SetErrorString("Unable to compile function to call "
340 "__introspection_dispatch_queue_item_get_info");
341 return return_value;
342 }
343
344 ExpressionResults func_call_ret;
345 Value results;
346 FunctionCaller *func_caller = m_get_item_info_impl_code->GetFunctionCaller();
347 if (!func_caller) {
348 LLDB_LOGF(log, "Could not retrieve function caller for "
349 "__introspection_dispatch_queue_item_get_info.");
350 error.SetErrorString("Could not retrieve function caller for "
351 "__introspection_dispatch_queue_item_get_info.");
352 return return_value;
353 }
354
355 func_call_ret = func_caller->ExecuteFunction(exe_ctx, args_addr_ptr: &args_addr, options,
356 diagnostic_manager&: diagnostics, results);
357 if (func_call_ret != eExpressionCompleted || !error.Success()) {
358 LLDB_LOGF(log,
359 "Unable to call "
360 "__introspection_dispatch_queue_item_get_info(), got "
361 "ExpressionResults %d, error contains %s",
362 func_call_ret, error.AsCString(""));
363 error.SetErrorString("Unable to call "
364 "__introspection_dispatch_queue_get_item_info() for "
365 "list of queues");
366 return return_value;
367 }
368
369 return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
370 load_addr: m_get_item_info_return_buffer_addr, byte_size: 8, LLDB_INVALID_ADDRESS, error);
371 if (!error.Success() ||
372 return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS) {
373 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
374 return return_value;
375 }
376
377 return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
378 load_addr: m_get_item_info_return_buffer_addr + 8, byte_size: 8, fail_value: 0, error);
379
380 if (!error.Success()) {
381 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
382 return return_value;
383 }
384 LLDB_LOGF(log,
385 "AppleGetItemInfoHandler called "
386 "__introspection_dispatch_queue_item_get_info (page_to_free == "
387 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64
388 ", size %" PRId64,
389 page_to_free, page_to_free_size, return_value.item_buffer_ptr,
390 return_value.item_buffer_size);
391
392 return return_value;
393}
394

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