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/Log.h"
24 #include "lldb/Utility/StreamString.h"
25
26 using namespace lldb;
27 using namespace lldb_private;
28
29 const char *AppleGetPendingItemsHandler::g_get_pending_items_function_name =
30 "__lldb_backtrace_recording_get_pending_items";
31 const char *AppleGetPendingItemsHandler::g_get_pending_items_function_code =
32 " \n\
33 extern \"C\" \n\
34 { \n\
35 /* \n\
36 * mach defines \n\
37 */ \n\
38 \n\
39 typedef unsigned int uint32_t; \n\
40 typedef unsigned long long uint64_t; \n\
41 typedef uint32_t mach_port_t; \n\
42 typedef mach_port_t vm_map_t; \n\
43 typedef int kern_return_t; \n\
44 typedef uint64_t mach_vm_address_t; \n\
45 typedef uint64_t mach_vm_size_t; \n\
46 \n\
47 mach_port_t mach_task_self (); \n\
48 kern_return_t mach_vm_deallocate (vm_map_t target, mach_vm_address_t address, mach_vm_size_t size); \n\
49 \n\
50 /* \n\
51 * libBacktraceRecording defines \n\
52 */ \n\
53 \n\
54 typedef uint32_t queue_list_scope_t; \n\
55 typedef void *dispatch_queue_t; \n\
56 typedef void *introspection_dispatch_queue_info_t; \n\
57 typedef void *introspection_dispatch_item_info_ref; \n\
58 \n\
59 extern uint64_t __introspection_dispatch_queue_get_pending_items (dispatch_queue_t queue, \n\
60 introspection_dispatch_item_info_ref *returned_queues_buffer, \n\
61 uint64_t *returned_queues_buffer_size); \n\
62 extern int printf(const char *format, ...); \n\
63 \n\
64 /* \n\
65 * return type define \n\
66 */ \n\
67 \n\
68 struct get_pending_items_return_values \n\
69 { \n\
70 uint64_t pending_items_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\
71 uint64_t pending_items_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\
72 uint64_t count; /* the number of items included in the queues buffer */ \n\
73 }; \n\
74 \n\
75 void __lldb_backtrace_recording_get_pending_items \n\
76 (struct get_pending_items_return_values *return_buffer, \n\
77 int debug, \n\
78 uint64_t /* dispatch_queue_t */ queue, \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_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\
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 return_buffer->count = __introspection_dispatch_queue_get_pending_items ( \n\
90 (void*) queue, \n\
91 (void**)&return_buffer->pending_items_buffer_ptr, \n\
92 &return_buffer->pending_items_buffer_size); \n\
93 if (debug) \n\
94 printf(\"result was count %lld\\n\", return_buffer->count); \n\
95 } \n\
96 } \n\
97 ";
98
AppleGetPendingItemsHandler(Process * process)99 AppleGetPendingItemsHandler::AppleGetPendingItemsHandler(Process *process)
100 : m_process(process), m_get_pending_items_impl_code(),
101 m_get_pending_items_function_mutex(),
102 m_get_pending_items_return_buffer_addr(LLDB_INVALID_ADDRESS),
103 m_get_pending_items_retbuffer_mutex() {}
104
~AppleGetPendingItemsHandler()105 AppleGetPendingItemsHandler::~AppleGetPendingItemsHandler() {}
106
Detach()107 void AppleGetPendingItemsHandler::Detach() {
108 if (m_process && m_process->IsAlive() &&
109 m_get_pending_items_return_buffer_addr != LLDB_INVALID_ADDRESS) {
110 std::unique_lock<std::mutex> lock(m_get_pending_items_retbuffer_mutex,
111 std::defer_lock);
112 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
113 m_process->DeallocateMemory(m_get_pending_items_return_buffer_addr);
114 }
115 }
116
117 // Compile our __lldb_backtrace_recording_get_pending_items() function (from
118 // the source above in g_get_pending_items_function_code) if we don't find that
119 // function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g.
120 // this would be the case for testing.)
121 //
122 // Insert the __lldb_backtrace_recording_get_pending_items into the inferior
123 // process if needed.
124 //
125 // Write the get_pending_items_arglist into the inferior's memory space to
126 // prepare for the call.
127 //
128 // Returns the address of the arguments written down in the inferior process,
129 // which can be used to make the function call.
130
SetupGetPendingItemsFunction(Thread & thread,ValueList & get_pending_items_arglist)131 lldb::addr_t AppleGetPendingItemsHandler::SetupGetPendingItemsFunction(
132 Thread &thread, ValueList &get_pending_items_arglist) {
133 ThreadSP thread_sp(thread.shared_from_this());
134 ExecutionContext exe_ctx(thread_sp);
135 DiagnosticManager diagnostics;
136 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
137
138 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
139 FunctionCaller *get_pending_items_caller = nullptr;
140
141 // Scope for mutex locker:
142 {
143 std::lock_guard<std::mutex> guard(m_get_pending_items_function_mutex);
144
145 // First stage is to make the ClangUtility to hold our injected function:
146
147 if (!m_get_pending_items_impl_code) {
148 if (g_get_pending_items_function_code != nullptr) {
149 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(
150 g_get_pending_items_function_code,
151 g_get_pending_items_function_name, eLanguageTypeC, exe_ctx);
152 if (!utility_fn_or_error) {
153 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(),
154 "Failed to create UtilityFunction for pending-items "
155 "introspection: {0}.");
156 return args_addr;
157 }
158 m_get_pending_items_impl_code = std::move(*utility_fn_or_error);
159 } else {
160 LLDB_LOGF(log, "No pending-items introspection code found.");
161 return LLDB_INVALID_ADDRESS;
162 }
163
164 // Next make the runner function for our implementation utility function.
165 Status error;
166 TypeSystemClang *clang_ast_context = ScratchTypeSystemClang::GetForTarget(
167 thread.GetProcess()->GetTarget());
168 CompilerType get_pending_items_return_type =
169 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
170 get_pending_items_caller =
171 m_get_pending_items_impl_code->MakeFunctionCaller(
172 get_pending_items_return_type, get_pending_items_arglist,
173 thread_sp, error);
174 if (error.Fail() || get_pending_items_caller == nullptr) {
175 LLDB_LOGF(log,
176 "Failed to install pending-items introspection function "
177 "caller: %s.",
178 error.AsCString());
179 m_get_pending_items_impl_code.reset();
180 return args_addr;
181 }
182 }
183 }
184
185 diagnostics.Clear();
186
187 if (get_pending_items_caller == nullptr) {
188 LLDB_LOGF(log, "Failed to get get_pending_items_caller.");
189 return LLDB_INVALID_ADDRESS;
190 }
191
192 // Now write down the argument values for this particular call. This looks
193 // like it might be a race condition if other threads were calling into here,
194 // but actually it isn't because we allocate a new args structure for this
195 // call by passing args_addr = LLDB_INVALID_ADDRESS...
196
197 if (!get_pending_items_caller->WriteFunctionArguments(
198 exe_ctx, args_addr, get_pending_items_arglist, diagnostics)) {
199 if (log) {
200 LLDB_LOGF(log, "Error writing pending-items function arguments.");
201 diagnostics.Dump(log);
202 }
203
204 return args_addr;
205 }
206
207 return args_addr;
208 }
209
210 AppleGetPendingItemsHandler::GetPendingItemsReturnInfo
GetPendingItems(Thread & thread,addr_t queue,addr_t page_to_free,uint64_t page_to_free_size,Status & error)211 AppleGetPendingItemsHandler::GetPendingItems(Thread &thread, addr_t queue,
212 addr_t page_to_free,
213 uint64_t page_to_free_size,
214 Status &error) {
215 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
216 ProcessSP process_sp(thread.CalculateProcess());
217 TargetSP target_sp(thread.CalculateTarget());
218 TypeSystemClang *clang_ast_context =
219 ScratchTypeSystemClang::GetForTarget(*target_sp);
220 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
221
222 GetPendingItemsReturnInfo return_value;
223 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
224 return_value.items_buffer_size = 0;
225 return_value.count = 0;
226
227 error.Clear();
228
229 if (!thread.SafeToCallFunctions()) {
230 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64,
231 thread.GetID());
232 error.SetErrorString("Not safe to call functions on this thread.");
233 return return_value;
234 }
235
236 // Set up the arguments for a call to
237
238 // struct get_pending_items_return_values
239 // {
240 // uint64_t pending_items_buffer_ptr; /* the address of the items
241 // buffer from libBacktraceRecording */
242 // uint64_t pending_items_buffer_size; /* the size of the items buffer
243 // from libBacktraceRecording */
244 // uint64_t count; /* the number of items included in the
245 // queues buffer */
246 // };
247 //
248 // void __lldb_backtrace_recording_get_pending_items
249 // (struct
250 // get_pending_items_return_values
251 // *return_buffer,
252 // int debug,
253 // uint64_t /* dispatch_queue_t */
254 // queue
255 // void *page_to_free,
256 // uint64_t page_to_free_size)
257
258 // Where the return_buffer argument points to a 24 byte region of memory
259 // already allocated by lldb in the inferior process.
260
261 CompilerType clang_void_ptr_type =
262 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
263 Value return_buffer_ptr_value;
264 return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar);
265 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
266
267 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt);
268 Value debug_value;
269 debug_value.SetValueType(Value::eValueTypeScalar);
270 debug_value.SetCompilerType(clang_int_type);
271
272 CompilerType clang_uint64_type =
273 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
274 Value queue_value;
275 queue_value.SetValueType(Value::eValueTypeScalar);
276 queue_value.SetCompilerType(clang_uint64_type);
277
278 Value page_to_free_value;
279 page_to_free_value.SetValueType(Value::eValueTypeScalar);
280 page_to_free_value.SetCompilerType(clang_void_ptr_type);
281
282 Value page_to_free_size_value;
283 page_to_free_size_value.SetValueType(Value::eValueTypeScalar);
284 page_to_free_size_value.SetCompilerType(clang_uint64_type);
285
286 std::lock_guard<std::mutex> guard(m_get_pending_items_retbuffer_mutex);
287 if (m_get_pending_items_return_buffer_addr == LLDB_INVALID_ADDRESS) {
288 addr_t bufaddr = process_sp->AllocateMemory(
289 32, ePermissionsReadable | ePermissionsWritable, error);
290 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
291 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "
292 "current queues func call");
293 return return_value;
294 }
295 m_get_pending_items_return_buffer_addr = bufaddr;
296 }
297
298 ValueList argument_values;
299
300 return_buffer_ptr_value.GetScalar() = m_get_pending_items_return_buffer_addr;
301 argument_values.PushValue(return_buffer_ptr_value);
302
303 debug_value.GetScalar() = 0;
304 argument_values.PushValue(debug_value);
305
306 queue_value.GetScalar() = queue;
307 argument_values.PushValue(queue_value);
308
309 if (page_to_free != LLDB_INVALID_ADDRESS)
310 page_to_free_value.GetScalar() = page_to_free;
311 else
312 page_to_free_value.GetScalar() = 0;
313 argument_values.PushValue(page_to_free_value);
314
315 page_to_free_size_value.GetScalar() = page_to_free_size;
316 argument_values.PushValue(page_to_free_size_value);
317
318 addr_t args_addr = SetupGetPendingItemsFunction(thread, argument_values);
319
320 DiagnosticManager diagnostics;
321 ExecutionContext exe_ctx;
322 FunctionCaller *get_pending_items_caller =
323 m_get_pending_items_impl_code->GetFunctionCaller();
324
325 EvaluateExpressionOptions options;
326 options.SetUnwindOnError(true);
327 options.SetIgnoreBreakpoints(true);
328 options.SetStopOthers(true);
329 #if __has_feature(address_sanitizer)
330 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
331 #else
332 options.SetTimeout(std::chrono::milliseconds(500));
333 #endif
334 options.SetTryAllThreads(false);
335 options.SetIsForUtilityExpr(true);
336 thread.CalculateExecutionContext(exe_ctx);
337
338 if (get_pending_items_caller == nullptr) {
339 error.SetErrorString("Unable to compile function to call "
340 "__introspection_dispatch_queue_get_pending_items");
341 return return_value;
342 }
343
344 ExpressionResults func_call_ret;
345 Value results;
346 func_call_ret = get_pending_items_caller->ExecuteFunction(
347 exe_ctx, &args_addr, options, diagnostics, results);
348 if (func_call_ret != eExpressionCompleted || !error.Success()) {
349 LLDB_LOGF(log,
350 "Unable to call "
351 "__introspection_dispatch_queue_get_pending_items(), got "
352 "ExpressionResults %d, error contains %s",
353 func_call_ret, error.AsCString(""));
354 error.SetErrorString("Unable to call "
355 "__introspection_dispatch_queue_get_pending_items() "
356 "for list of queues");
357 return return_value;
358 }
359
360 return_value.items_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
361 m_get_pending_items_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);
362 if (!error.Success() ||
363 return_value.items_buffer_ptr == LLDB_INVALID_ADDRESS) {
364 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
365 return return_value;
366 }
367
368 return_value.items_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
369 m_get_pending_items_return_buffer_addr + 8, 8, 0, error);
370
371 if (!error.Success()) {
372 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
373 return return_value;
374 }
375
376 return_value.count = m_process->ReadUnsignedIntegerFromMemory(
377 m_get_pending_items_return_buffer_addr + 16, 8, 0, error);
378 if (!error.Success()) {
379 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS;
380 return return_value;
381 }
382
383 LLDB_LOGF(log,
384 "AppleGetPendingItemsHandler called "
385 "__introspection_dispatch_queue_get_pending_items "
386 "(page_to_free == 0x%" PRIx64 ", size = %" PRId64
387 "), returned page is at 0x%" PRIx64 ", size %" PRId64
388 ", count = %" PRId64,
389 page_to_free, page_to_free_size, return_value.items_buffer_ptr,
390 return_value.items_buffer_size, return_value.count);
391
392 return return_value;
393 }
394