1 //===-- AppleGetPendingItemsHandler.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 "AppleGetPendingItemsHandler.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 *AppleGetPendingItemsHandler::g_get_pending_items_function_name =
31 "__lldb_backtrace_recording_get_pending_items";
32 const char *AppleGetPendingItemsHandler::g_get_pending_items_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_get_pending_items (dispatch_queue_t queue, \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_pending_items_return_values \n\
70 { \n\
71 uint64_t pending_items_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\
72 uint64_t pending_items_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\
73 uint64_t count; /* the number of items included in the queues buffer */ \n\
74 }; \n\
75 \n\
76 void __lldb_backtrace_recording_get_pending_items \n\
77 (struct get_pending_items_return_values *return_buffer, \n\
78 int debug, \n\
79 uint64_t /* dispatch_queue_t */ queue, \n\
80 void *page_to_free, \n\
81 uint64_t page_to_free_size) \n\
82 { \n\
83 if (debug) \n\
84 printf (\"entering get_pending_items with args return_buffer == %p, debug == %d, queue == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, queue, page_to_free, page_to_free_size); \n\
85 if (page_to_free != 0) \n\
86 { \n\
87 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\
88 } \n\
89 \n\
90 return_buffer->count = __introspection_dispatch_queue_get_pending_items ( \n\
91 (void*) queue, \n\
92 (void**)&return_buffer->pending_items_buffer_ptr, \n\
93 &return_buffer->pending_items_buffer_size); \n\
94 if (debug) \n\
95 printf(\"result was count %lld\\n\", return_buffer->count); \n\
96 } \n\
97 } \n\
98 ";
99
AppleGetPendingItemsHandler(Process * process)100 AppleGetPendingItemsHandler::AppleGetPendingItemsHandler(Process *process)
101 : m_process(process), m_get_pending_items_impl_code(),
102 m_get_pending_items_function_mutex(),
103 m_get_pending_items_return_buffer_addr(LLDB_INVALID_ADDRESS),
104 m_get_pending_items_retbuffer_mutex() {}
105
106 AppleGetPendingItemsHandler::~AppleGetPendingItemsHandler() = default;
107
Detach()108 void AppleGetPendingItemsHandler::Detach() {
109 if (m_process && m_process->IsAlive() &&
110 m_get_pending_items_return_buffer_addr != LLDB_INVALID_ADDRESS) {
111 std::unique_lock<std::mutex> lock(m_get_pending_items_retbuffer_mutex,
112 std::defer_lock);
113 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
114 m_process->DeallocateMemory(m_get_pending_items_return_buffer_addr);
115 }
116 }
117
118 // Compile our __lldb_backtrace_recording_get_pending_items() function (from
119 // the source above in g_get_pending_items_function_code) if we don't find that
120 // function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g.
121 // this would be the case for testing.)
122 //
123 // Insert the __lldb_backtrace_recording_get_pending_items into the inferior
124 // process if needed.
125 //
126 // Write the get_pending_items_arglist into the inferior's memory space to
127 // prepare for the call.
128 //
129 // Returns the address of the arguments written down in the inferior process,
130 // which can be used to make the function call.
131
SetupGetPendingItemsFunction(Thread & thread,ValueList & get_pending_items_arglist)132 lldb::addr_t AppleGetPendingItemsHandler::SetupGetPendingItemsFunction(
133 Thread &thread, ValueList &get_pending_items_arglist) {
134 ThreadSP thread_sp(thread.shared_from_this());
135 ExecutionContext exe_ctx(thread_sp);
136 DiagnosticManager diagnostics;
137 Log *log = GetLog(LLDBLog::SystemRuntime);
138
139 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
140 FunctionCaller *get_pending_items_caller = nullptr;
141
142 // Scope for mutex locker:
143 {
144 std::lock_guard<std::mutex> guard(m_get_pending_items_function_mutex);
145
146 // First stage is to make the ClangUtility to hold our injected function:
147
148 if (!m_get_pending_items_impl_code) {
149 if (g_get_pending_items_function_code != nullptr) {
150 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(
151 g_get_pending_items_function_code,
152 g_get_pending_items_function_name, eLanguageTypeC, exe_ctx);
153 if (!utility_fn_or_error) {
154 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(),
155 "Failed to create UtilityFunction for pending-items "
156 "introspection: {0}.");
157 return args_addr;
158 }
159 m_get_pending_items_impl_code = std::move(*utility_fn_or_error);
160 } else {
161 LLDB_LOGF(log, "No pending-items introspection code found.");
162 return LLDB_INVALID_ADDRESS;
163 }
164
165 // Next make the runner function for our implementation utility function.
166 Status error;
167 TypeSystemClangSP scratch_ts_sp = ScratchTypeSystemClang::GetForTarget(
168 thread.GetProcess()->GetTarget());
169 CompilerType get_pending_items_return_type =
170 scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType();
171 get_pending_items_caller =
172 m_get_pending_items_impl_code->MakeFunctionCaller(
173 get_pending_items_return_type, get_pending_items_arglist,
174 thread_sp, error);
175 if (error.Fail() || get_pending_items_caller == nullptr) {
176 LLDB_LOGF(log,
177 "Failed to install pending-items introspection function "
178 "caller: %s.",
179 error.AsCString());
180 m_get_pending_items_impl_code.reset();
181 return args_addr;
182 }
183 }
184 }
185
186 diagnostics.Clear();
187
188 if (get_pending_items_caller == nullptr) {
189 LLDB_LOGF(log, "Failed to get get_pending_items_caller.");
190 return LLDB_INVALID_ADDRESS;
191 }
192
193 // Now write down the argument values for this particular call. This looks
194 // like it might be a race condition if other threads were calling into here,
195 // but actually it isn't because we allocate a new args structure for this
196 // call by passing args_addr = LLDB_INVALID_ADDRESS...
197
198 if (!get_pending_items_caller->WriteFunctionArguments(
199 exe_ctx, args_addr, get_pending_items_arglist, diagnostics)) {
200 if (log) {
201 LLDB_LOGF(log, "Error writing pending-items function arguments.");
202 diagnostics.Dump(log);
203 }
204
205 return args_addr;
206 }
207
208 return args_addr;
209 }
210
211 AppleGetPendingItemsHandler::GetPendingItemsReturnInfo
GetPendingItems(Thread & thread,addr_t queue,addr_t page_to_free,uint64_t page_to_free_size,Status & error)212 AppleGetPendingItemsHandler::GetPendingItems(Thread &thread, addr_t queue,
213 addr_t page_to_free,
214 uint64_t page_to_free_size,
215 Status &error) {
216 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
217 ProcessSP process_sp(thread.CalculateProcess());
218 TargetSP target_sp(thread.CalculateTarget());
219 TypeSystemClangSP scratch_ts_sp =
220 ScratchTypeSystemClang::GetForTarget(*target_sp);
221 Log *log = GetLog(LLDBLog::SystemRuntime);
222
223 GetPendingItemsReturnInfo return_value;
224 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
225 return_value.items_buffer_size = 0;
226 return_value.count = 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_pending_items_return_values
240 // {
241 // uint64_t pending_items_buffer_ptr; /* the address of the items
242 // buffer from libBacktraceRecording */
243 // uint64_t pending_items_buffer_size; /* the size of the items buffer
244 // from libBacktraceRecording */
245 // uint64_t count; /* the number of items included in the
246 // queues buffer */
247 // };
248 //
249 // void __lldb_backtrace_recording_get_pending_items
250 // (struct
251 // get_pending_items_return_values
252 // *return_buffer,
253 // int debug,
254 // uint64_t /* dispatch_queue_t */
255 // queue
256 // void *page_to_free,
257 // uint64_t page_to_free_size)
258
259 // Where the return_buffer argument points to a 24 byte region of memory
260 // already allocated by lldb in the inferior process.
261
262 CompilerType clang_void_ptr_type =
263 scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType();
264 Value return_buffer_ptr_value;
265 return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar);
266 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
267
268 CompilerType clang_int_type = scratch_ts_sp->GetBasicType(eBasicTypeInt);
269 Value debug_value;
270 debug_value.SetValueType(Value::ValueType::Scalar);
271 debug_value.SetCompilerType(clang_int_type);
272
273 CompilerType clang_uint64_type =
274 scratch_ts_sp->GetBasicType(eBasicTypeUnsignedLongLong);
275 Value queue_value;
276 queue_value.SetValueType(Value::ValueType::Scalar);
277 queue_value.SetCompilerType(clang_uint64_type);
278
279 Value page_to_free_value;
280 page_to_free_value.SetValueType(Value::ValueType::Scalar);
281 page_to_free_value.SetCompilerType(clang_void_ptr_type);
282
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_pending_items_retbuffer_mutex);
288 if (m_get_pending_items_return_buffer_addr == LLDB_INVALID_ADDRESS) {
289 addr_t bufaddr = process_sp->AllocateMemory(
290 32, 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_pending_items_return_buffer_addr = bufaddr;
297 }
298
299 ValueList argument_values;
300
301 return_buffer_ptr_value.GetScalar() = m_get_pending_items_return_buffer_addr;
302 argument_values.PushValue(return_buffer_ptr_value);
303
304 debug_value.GetScalar() = 0;
305 argument_values.PushValue(debug_value);
306
307 queue_value.GetScalar() = queue;
308 argument_values.PushValue(queue_value);
309
310 if (page_to_free != LLDB_INVALID_ADDRESS)
311 page_to_free_value.GetScalar() = page_to_free;
312 else
313 page_to_free_value.GetScalar() = 0;
314 argument_values.PushValue(page_to_free_value);
315
316 page_to_free_size_value.GetScalar() = page_to_free_size;
317 argument_values.PushValue(page_to_free_size_value);
318
319 addr_t args_addr = SetupGetPendingItemsFunction(thread, argument_values);
320
321 DiagnosticManager diagnostics;
322 ExecutionContext exe_ctx;
323 FunctionCaller *get_pending_items_caller =
324 m_get_pending_items_impl_code->GetFunctionCaller();
325
326 EvaluateExpressionOptions options;
327 options.SetUnwindOnError(true);
328 options.SetIgnoreBreakpoints(true);
329 options.SetStopOthers(true);
330 #if __has_feature(address_sanitizer)
331 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
332 #else
333 options.SetTimeout(std::chrono::milliseconds(500));
334 #endif
335 options.SetTryAllThreads(false);
336 options.SetIsForUtilityExpr(true);
337 thread.CalculateExecutionContext(exe_ctx);
338
339 if (get_pending_items_caller == nullptr) {
340 error.SetErrorString("Unable to compile function to call "
341 "__introspection_dispatch_queue_get_pending_items");
342 return return_value;
343 }
344
345 ExpressionResults func_call_ret;
346 Value results;
347 func_call_ret = get_pending_items_caller->ExecuteFunction(
348 exe_ctx, &args_addr, options, diagnostics, results);
349 if (func_call_ret != eExpressionCompleted || !error.Success()) {
350 LLDB_LOGF(log,
351 "Unable to call "
352 "__introspection_dispatch_queue_get_pending_items(), got "
353 "ExpressionResults %d, error contains %s",
354 func_call_ret, error.AsCString(""));
355 error.SetErrorString("Unable to call "
356 "__introspection_dispatch_queue_get_pending_items() "
357 "for list of queues");
358 return return_value;
359 }
360
361 return_value.items_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
362 m_get_pending_items_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);
363 if (!error.Success() ||
364 return_value.items_buffer_ptr == LLDB_INVALID_ADDRESS) {
365 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
366 return return_value;
367 }
368
369 return_value.items_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
370 m_get_pending_items_return_buffer_addr + 8, 8, 0, error);
371
372 if (!error.Success()) {
373 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
374 return return_value;
375 }
376
377 return_value.count = m_process->ReadUnsignedIntegerFromMemory(
378 m_get_pending_items_return_buffer_addr + 16, 8, 0, error);
379 if (!error.Success()) {
380 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
381 return return_value;
382 }
383
384 LLDB_LOGF(log,
385 "AppleGetPendingItemsHandler called "
386 "__introspection_dispatch_queue_get_pending_items "
387 "(page_to_free == 0x%" PRIx64 ", size = %" PRId64
388 "), returned page is at 0x%" PRIx64 ", size %" PRId64
389 ", count = %" PRId64,
390 page_to_free, page_to_free_size, return_value.items_buffer_ptr,
391 return_value.items_buffer_size, return_value.count);
392
393 return return_value;
394 }
395