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
27 using namespace lldb;
28 using namespace lldb_private;
29
30 const char *AppleGetItemInfoHandler::g_get_item_info_function_name =
31 "__lldb_backtrace_recording_get_item_info";
32 const char *AppleGetItemInfoHandler::g_get_item_info_function_code =
33 " \n\
34 extern \"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
AppleGetItemInfoHandler(Process * process)96 AppleGetItemInfoHandler::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
102 AppleGetItemInfoHandler::~AppleGetItemInfoHandler() = default;
103
Detach()104 void 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(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
SetupGetItemInfoFunction(Thread & thread,ValueList & get_item_info_arglist)129 lldb::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(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 g_get_item_info_function_code, g_get_item_info_function_name,
148 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 eLanguageTypeC);
163 if (auto err = type_system_or_err.takeError()) {
164 LLDB_LOG_ERROR(log, std::move(err),
165 "Error inseting get-item-info function");
166 return args_addr;
167 }
168 CompilerType get_item_info_return_type =
169 type_system_or_err->GetBasicTypeFromAST(eBasicTypeVoid)
170 .GetPointerType();
171
172 Status error;
173 get_item_info_caller = m_get_item_info_impl_code->MakeFunctionCaller(
174 get_item_info_return_type, get_item_info_arglist,
175 thread.shared_from_this(), error);
176 if (error.Fail() || get_item_info_caller == nullptr) {
177 LLDB_LOGF(log, "Error Inserting get-item-info function: \"%s\".",
178 error.AsCString());
179 return args_addr;
180 }
181 } else {
182 // If it's already made, then we can just retrieve the caller:
183 get_item_info_caller = m_get_item_info_impl_code->GetFunctionCaller();
184 if (!get_item_info_caller) {
185 LLDB_LOGF(log, "Failed to get get-item-info introspection caller.");
186 m_get_item_info_impl_code.reset();
187 return args_addr;
188 }
189 }
190 }
191
192 diagnostics.Clear();
193
194 // Now write down the argument values for this particular call. This looks
195 // like it might be a race condition if other threads were calling into here,
196 // but actually it isn't because we allocate a new args structure for this
197 // call by passing args_addr = LLDB_INVALID_ADDRESS...
198
199 if (!get_item_info_caller->WriteFunctionArguments(
200 exe_ctx, args_addr, get_item_info_arglist, diagnostics)) {
201 if (log) {
202 LLDB_LOGF(log, "Error writing get-item-info function arguments.");
203 diagnostics.Dump(log);
204 }
205
206 return args_addr;
207 }
208
209 return args_addr;
210 }
211
212 AppleGetItemInfoHandler::GetItemInfoReturnInfo
GetItemInfo(Thread & thread,uint64_t item,addr_t page_to_free,uint64_t page_to_free_size,Status & error)213 AppleGetItemInfoHandler::GetItemInfo(Thread &thread, uint64_t item,
214 addr_t page_to_free,
215 uint64_t page_to_free_size,
216 Status &error) {
217 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
218 ProcessSP process_sp(thread.CalculateProcess());
219 TargetSP target_sp(thread.CalculateTarget());
220 TypeSystemClang *clang_ast_context =
221 ScratchTypeSystemClang::GetForTarget(*target_sp);
222 Log *log = GetLog(LLDBLog::SystemRuntime);
223
224 GetItemInfoReturnInfo return_value;
225 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
226 return_value.item_buffer_size = 0;
227
228 error.Clear();
229
230 if (!thread.SafeToCallFunctions()) {
231 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64,
232 thread.GetID());
233 error.SetErrorString("Not safe to call functions on this thread.");
234 return return_value;
235 }
236
237 // Set up the arguments for a call to
238
239 // struct get_item_info_return_values
240 // {
241 // uint64_t item_info_buffer_ptr; /* the address of the items buffer
242 // from libBacktraceRecording */
243 // uint64_t item_info_buffer_size; /* the size of the items buffer from
244 // libBacktraceRecording */
245 // };
246 //
247 // void __lldb_backtrace_recording_get_item_info
248 // (struct
249 // get_item_info_return_values
250 // *return_buffer,
251 // int debug,
252 // uint64_t item,
253 // void *page_to_free,
254 // uint64_t page_to_free_size)
255
256 // Where the return_buffer argument points to a 24 byte region of memory
257 // already allocated by lldb in the inferior process.
258
259 CompilerType clang_void_ptr_type =
260 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
261 Value return_buffer_ptr_value;
262 return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar);
263 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
264
265 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt);
266 Value debug_value;
267 debug_value.SetValueType(Value::ValueType::Scalar);
268 debug_value.SetCompilerType(clang_int_type);
269
270 CompilerType clang_uint64_type =
271 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
272 Value item_value;
273 item_value.SetValueType(Value::ValueType::Scalar);
274 item_value.SetCompilerType(clang_uint64_type);
275
276 Value page_to_free_value;
277 page_to_free_value.SetValueType(Value::ValueType::Scalar);
278 page_to_free_value.SetCompilerType(clang_void_ptr_type);
279
280 Value page_to_free_size_value;
281 page_to_free_size_value.SetValueType(Value::ValueType::Scalar);
282 page_to_free_size_value.SetCompilerType(clang_uint64_type);
283
284 std::lock_guard<std::mutex> guard(m_get_item_info_retbuffer_mutex);
285 if (m_get_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS) {
286 addr_t bufaddr = process_sp->AllocateMemory(
287 32, ePermissionsReadable | ePermissionsWritable, error);
288 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
289 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "
290 "current queues func call");
291 return return_value;
292 }
293 m_get_item_info_return_buffer_addr = bufaddr;
294 }
295
296 ValueList argument_values;
297
298 return_buffer_ptr_value.GetScalar() = m_get_item_info_return_buffer_addr;
299 argument_values.PushValue(return_buffer_ptr_value);
300
301 debug_value.GetScalar() = 0;
302 argument_values.PushValue(debug_value);
303
304 item_value.GetScalar() = item;
305 argument_values.PushValue(item_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(page_to_free_value);
312
313 page_to_free_size_value.GetScalar() = page_to_free_size;
314 argument_values.PushValue(page_to_free_size_value);
315
316 addr_t args_addr = SetupGetItemInfoFunction(thread, argument_values);
317
318 DiagnosticManager diagnostics;
319 ExecutionContext exe_ctx;
320 EvaluateExpressionOptions options;
321 options.SetUnwindOnError(true);
322 options.SetIgnoreBreakpoints(true);
323 options.SetStopOthers(true);
324 #if __has_feature(address_sanitizer)
325 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
326 #else
327 options.SetTimeout(std::chrono::milliseconds(500));
328 #endif
329 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
330 options.SetTryAllThreads(false);
331 options.SetIsForUtilityExpr(true);
332 thread.CalculateExecutionContext(exe_ctx);
333
334 if (!m_get_item_info_impl_code) {
335 error.SetErrorString("Unable to compile function to call "
336 "__introspection_dispatch_queue_item_get_info");
337 return return_value;
338 }
339
340 ExpressionResults func_call_ret;
341 Value results;
342 FunctionCaller *func_caller = m_get_item_info_impl_code->GetFunctionCaller();
343 if (!func_caller) {
344 LLDB_LOGF(log, "Could not retrieve function caller for "
345 "__introspection_dispatch_queue_item_get_info.");
346 error.SetErrorString("Could not retrieve function caller for "
347 "__introspection_dispatch_queue_item_get_info.");
348 return return_value;
349 }
350
351 func_call_ret = func_caller->ExecuteFunction(exe_ctx, &args_addr, options,
352 diagnostics, results);
353 if (func_call_ret != eExpressionCompleted || !error.Success()) {
354 LLDB_LOGF(log,
355 "Unable to call "
356 "__introspection_dispatch_queue_item_get_info(), got "
357 "ExpressionResults %d, error contains %s",
358 func_call_ret, error.AsCString(""));
359 error.SetErrorString("Unable to call "
360 "__introspection_dispatch_queue_get_item_info() for "
361 "list of queues");
362 return return_value;
363 }
364
365 return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
366 m_get_item_info_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);
367 if (!error.Success() ||
368 return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS) {
369 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
370 return return_value;
371 }
372
373 return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
374 m_get_item_info_return_buffer_addr + 8, 8, 0, error);
375
376 if (!error.Success()) {
377 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
378 return return_value;
379 }
380 LLDB_LOGF(log,
381 "AppleGetItemInfoHandler called "
382 "__introspection_dispatch_queue_item_get_info (page_to_free == "
383 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64
384 ", size %" PRId64,
385 page_to_free, page_to_free_size, return_value.item_buffer_ptr,
386 return_value.item_buffer_size);
387
388 return return_value;
389 }
390