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
27using namespace lldb;
28using namespace lldb_private;
29
30const char *AppleGetPendingItemsHandler::g_get_pending_items_function_name =
31 "__lldb_backtrace_recording_get_pending_items";
32const char *AppleGetPendingItemsHandler::g_get_pending_items_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_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
100AppleGetPendingItemsHandler::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
106AppleGetPendingItemsHandler::~AppleGetPendingItemsHandler() = default;
107
108void 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(ptr: 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
132lldb::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(mask: 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 expression: g_get_pending_items_function_code,
152 name: g_get_pending_items_function_name, language: 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 target&: thread.GetProcess()->GetTarget());
169 CompilerType get_pending_items_return_type =
170 scratch_ts_sp->GetBasicType(type: eBasicTypeVoid).GetPointerType();
171 get_pending_items_caller =
172 m_get_pending_items_impl_code->MakeFunctionCaller(
173 return_type: get_pending_items_return_type, arg_value_list: get_pending_items_arglist,
174 compilation_thread: 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_ref&: args_addr, arg_values&: get_pending_items_arglist, diagnostic_manager&: 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
211AppleGetPendingItemsHandler::GetPendingItemsReturnInfo
212AppleGetPendingItemsHandler::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(idx: 0);
217 ProcessSP process_sp(thread.CalculateProcess());
218 TargetSP target_sp(thread.CalculateTarget());
219 TypeSystemClangSP scratch_ts_sp =
220 ScratchTypeSystemClang::GetForTarget(target&: *target_sp);
221 Log *log = GetLog(mask: 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 =
234 Status::FromErrorString(str: "Not safe to call functions on this thread.");
235 return return_value;
236 }
237
238 // Set up the arguments for a call to
239
240 // struct get_pending_items_return_values
241 // {
242 // uint64_t pending_items_buffer_ptr; /* the address of the items
243 // buffer from libBacktraceRecording */
244 // uint64_t pending_items_buffer_size; /* the size of the items buffer
245 // from libBacktraceRecording */
246 // uint64_t count; /* the number of items included in the
247 // queues buffer */
248 // };
249 //
250 // void __lldb_backtrace_recording_get_pending_items
251 // (struct
252 // get_pending_items_return_values
253 // *return_buffer,
254 // int debug,
255 // uint64_t /* dispatch_queue_t */
256 // queue
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 queue_value;
277 queue_value.SetValueType(Value::ValueType::Scalar);
278 queue_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_pending_items_retbuffer_mutex);
289 if (m_get_pending_items_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_pending_items_return_buffer_addr = bufaddr;
298 }
299
300 ValueList argument_values;
301
302 return_buffer_ptr_value.GetScalar() = m_get_pending_items_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 queue_value.GetScalar() = queue;
309 argument_values.PushValue(value: queue_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 = SetupGetPendingItemsFunction(thread, get_pending_items_arglist&: argument_values);
321
322 DiagnosticManager diagnostics;
323 ExecutionContext exe_ctx;
324 FunctionCaller *get_pending_items_caller =
325 m_get_pending_items_impl_code->GetFunctionCaller();
326
327 EvaluateExpressionOptions options;
328 options.SetUnwindOnError(true);
329 options.SetIgnoreBreakpoints(true);
330 options.SetStopOthers(true);
331#if __has_feature(address_sanitizer)
332 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
333#else
334 options.SetTimeout(std::chrono::milliseconds(500));
335#endif
336 options.SetTryAllThreads(false);
337 options.SetIsForUtilityExpr(true);
338 thread.CalculateExecutionContext(exe_ctx);
339
340 if (get_pending_items_caller == nullptr) {
341 error = Status::FromErrorString(
342 str: "Unable to compile function to call "
343 "__introspection_dispatch_queue_get_pending_items");
344 return return_value;
345 }
346
347 ExpressionResults func_call_ret;
348 Value results;
349 func_call_ret = get_pending_items_caller->ExecuteFunction(
350 exe_ctx, args_addr_ptr: &args_addr, options, diagnostic_manager&: diagnostics, results);
351 if (func_call_ret != eExpressionCompleted || !error.Success()) {
352 LLDB_LOGF(log,
353 "Unable to call "
354 "__introspection_dispatch_queue_get_pending_items(), got "
355 "ExpressionResults %d, error contains %s",
356 func_call_ret, error.AsCString(""));
357 error = Status::FromErrorString(
358 str: "Unable to call "
359 "__introspection_dispatch_queue_get_pending_items() "
360 "for list of queues");
361 return return_value;
362 }
363
364 return_value.items_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
365 load_addr: m_get_pending_items_return_buffer_addr, byte_size: 8, LLDB_INVALID_ADDRESS, error);
366 if (!error.Success() ||
367 return_value.items_buffer_ptr == LLDB_INVALID_ADDRESS) {
368 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
369 return return_value;
370 }
371
372 return_value.items_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
373 load_addr: m_get_pending_items_return_buffer_addr + 8, byte_size: 8, fail_value: 0, error);
374
375 if (!error.Success()) {
376 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
377 return return_value;
378 }
379
380 return_value.count = m_process->ReadUnsignedIntegerFromMemory(
381 load_addr: m_get_pending_items_return_buffer_addr + 16, byte_size: 8, fail_value: 0, error);
382 if (!error.Success()) {
383 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
384 return return_value;
385 }
386
387 LLDB_LOGF(log,
388 "AppleGetPendingItemsHandler called "
389 "__introspection_dispatch_queue_get_pending_items "
390 "(page_to_free == 0x%" PRIx64 ", size = %" PRId64
391 "), returned page is at 0x%" PRIx64 ", size %" PRId64
392 ", count = %" PRId64,
393 page_to_free, page_to_free_size, return_value.items_buffer_ptr,
394 return_value.items_buffer_size, return_value.count);
395
396 return return_value;
397}
398

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