1 //===-- AppleGetQueuesHandler.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 "AppleGetQueuesHandler.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 *AppleGetQueuesHandler::g_get_current_queues_function_name =
30 "__lldb_backtrace_recording_get_current_queues";
31 const char *AppleGetQueuesHandler::g_get_current_queues_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 *introspection_dispatch_queue_info_t; \n\
56 \n\
57 extern uint64_t __introspection_dispatch_get_queues (queue_list_scope_t scope, \n\
58 introspection_dispatch_queue_info_t *returned_queues_buffer, \n\
59 uint64_t *returned_queues_buffer_size); \n\
60 extern int printf(const char *format, ...); \n\
61 \n\
62 /* \n\
63 * return type define \n\
64 */ \n\
65 \n\
66 struct get_current_queues_return_values \n\
67 { \n\
68 uint64_t queues_buffer_ptr; /* the address of the queues buffer from libBacktraceRecording */ \n\
69 uint64_t queues_buffer_size; /* the size of the queues buffer from libBacktraceRecording */ \n\
70 uint64_t count; /* the number of queues included in the queues buffer */ \n\
71 }; \n\
72 \n\
73 void __lldb_backtrace_recording_get_current_queues \n\
74 (struct get_current_queues_return_values *return_buffer, \n\
75 int debug, \n\
76 void *page_to_free, \n\
77 uint64_t page_to_free_size) \n\
78 { \n\
79 if (debug) \n\
80 printf (\"entering get_current_queues with args %p, %d, 0x%p, 0x%llx\\n\", return_buffer, debug, page_to_free, page_to_free_size); \n\
81 if (page_to_free != 0) \n\
82 { \n\
83 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\
84 } \n\
85 \n\
86 return_buffer->count = __introspection_dispatch_get_queues ( \n\
87 /* QUEUES_WITH_ANY_ITEMS */ 2, \n\
88 (void**)&return_buffer->queues_buffer_ptr, \n\
89 &return_buffer->queues_buffer_size); \n\
90 if (debug) \n\
91 printf(\"result was count %lld\\n\", return_buffer->count); \n\
92 } \n\
93 } \n\
94 ";
95
AppleGetQueuesHandler(Process * process)96 AppleGetQueuesHandler::AppleGetQueuesHandler(Process *process)
97 : m_process(process), m_get_queues_impl_code_up(),
98 m_get_queues_function_mutex(),
99 m_get_queues_return_buffer_addr(LLDB_INVALID_ADDRESS),
100 m_get_queues_retbuffer_mutex() {}
101
~AppleGetQueuesHandler()102 AppleGetQueuesHandler::~AppleGetQueuesHandler() {}
103
Detach()104 void AppleGetQueuesHandler::Detach() {
105
106 if (m_process && m_process->IsAlive() &&
107 m_get_queues_return_buffer_addr != LLDB_INVALID_ADDRESS) {
108 std::unique_lock<std::mutex> lock(m_get_queues_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_queues_return_buffer_addr);
112 }
113 }
114
115 // Construct a CompilerType for the structure that
116 // g_get_current_queues_function_code will return by value so we can extract
117 // the fields after performing the function call. i.e. we are getting this
118 // struct returned to us:
119 //
120 // struct get_current_queues_return_values
121 // {
122 // introspection_dispatch_queue_info_t *queues_buffer;
123 // uint64_t queues_buffer_size;
124 // uint64_t count;
125 // };
126
127 // Compile our __lldb_backtrace_recording_get_current_queues() function (from
128 // the source above in g_get_current_queues_function_code) if we don't find
129 // that function in the inferior already with USE_BUILTIN_FUNCTION defined.
130 // (e.g. this would be the case for testing.)
131 //
132 // Insert the __lldb_backtrace_recording_get_current_queues into the inferior
133 // process if needed.
134 //
135 // Write the get_queues_arglist into the inferior's memory space to prepare for
136 // the call.
137 //
138 // Returns the address of the arguments written down in the inferior process,
139 // which can be used to make the function call.
140
141 lldb::addr_t
SetupGetQueuesFunction(Thread & thread,ValueList & get_queues_arglist)142 AppleGetQueuesHandler::SetupGetQueuesFunction(Thread &thread,
143 ValueList &get_queues_arglist) {
144 ThreadSP thread_sp(thread.shared_from_this());
145 ExecutionContext exe_ctx(thread_sp);
146
147 Address impl_code_address;
148 DiagnosticManager diagnostics;
149 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
150 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
151
152 FunctionCaller *get_queues_caller = nullptr;
153
154 // Scope for mutex locker:
155 {
156 std::lock_guard<std::mutex> guard(m_get_queues_function_mutex);
157
158 // First stage is to make the ClangUtility to hold our injected function:
159
160 if (!m_get_queues_impl_code_up) {
161 if (g_get_current_queues_function_code != nullptr) {
162 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(
163 g_get_current_queues_function_code,
164 g_get_current_queues_function_name, eLanguageTypeC, exe_ctx);
165 if (!utility_fn_or_error) {
166 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(),
167 "Failed to create UtilityFunction for queues "
168 "introspection: {0}.");
169 return args_addr;
170 }
171 m_get_queues_impl_code_up = std::move(*utility_fn_or_error);
172 } else {
173 if (log) {
174 LLDB_LOGF(log, "No queues introspection code found.");
175 diagnostics.Dump(log);
176 }
177 return LLDB_INVALID_ADDRESS;
178 }
179 }
180
181 // Next make the runner function for our implementation utility function.
182 TypeSystemClang *clang_ast_context =
183 ScratchTypeSystemClang::GetForTarget(thread.GetProcess()->GetTarget());
184 CompilerType get_queues_return_type =
185 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
186 Status error;
187 get_queues_caller = m_get_queues_impl_code_up->MakeFunctionCaller(
188 get_queues_return_type, get_queues_arglist, thread_sp, error);
189 if (error.Fail() || get_queues_caller == nullptr) {
190 LLDB_LOGF(log,
191 "Could not get function caller for get-queues function: %s.",
192 error.AsCString());
193 return args_addr;
194 }
195 }
196
197 diagnostics.Clear();
198
199 // Now write down the argument values for this particular call. This looks
200 // like it might be a race condition if other threads were calling into here,
201 // but actually it isn't because we allocate a new args structure for this
202 // call by passing args_addr = LLDB_INVALID_ADDRESS...
203
204 if (!get_queues_caller->WriteFunctionArguments(
205 exe_ctx, args_addr, get_queues_arglist, diagnostics)) {
206 if (log) {
207 LLDB_LOGF(log, "Error writing get-queues function arguments.");
208 diagnostics.Dump(log);
209 }
210 return args_addr;
211 }
212
213 return args_addr;
214 }
215
216 AppleGetQueuesHandler::GetQueuesReturnInfo
GetCurrentQueues(Thread & thread,addr_t page_to_free,uint64_t page_to_free_size,Status & error)217 AppleGetQueuesHandler::GetCurrentQueues(Thread &thread, addr_t page_to_free,
218 uint64_t page_to_free_size,
219 Status &error) {
220 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
221 ProcessSP process_sp(thread.CalculateProcess());
222 TargetSP target_sp(thread.CalculateTarget());
223 TypeSystemClang *clang_ast_context =
224 ScratchTypeSystemClang::GetForTarget(*target_sp);
225 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
226
227 GetQueuesReturnInfo return_value;
228 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
229 return_value.queues_buffer_size = 0;
230 return_value.count = 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_current_queues_return_values
244 // {
245 // uint64_t queues_buffer_ptr; /* the address of the queues buffer from
246 // libBacktraceRecording */
247 // uint64_t queues_buffer_size; /* the size of the queues buffer from
248 // libBacktraceRecording */
249 // uint64_t count; /* the number of queues included in the
250 // queues buffer */
251 // };
252 //
253 // void
254 // __lldb_backtrace_recording_get_current_queues
255 // (struct
256 // get_current_queues_return_values
257 // *return_buffer,
258 // void *page_to_free,
259 // uint64_t page_to_free_size);
260
261 // Where the return_buffer argument points to a 24 byte region of memory
262 // already allocated by lldb in the inferior process.
263
264 CompilerType clang_void_ptr_type =
265 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
266 Value return_buffer_ptr_value;
267 return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar);
268 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
269
270 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt);
271 Value debug_value;
272 debug_value.SetValueType(Value::eValueTypeScalar);
273 debug_value.SetCompilerType(clang_int_type);
274
275 Value page_to_free_value;
276 page_to_free_value.SetValueType(Value::eValueTypeScalar);
277 page_to_free_value.SetCompilerType(clang_void_ptr_type);
278
279 CompilerType clang_uint64_type =
280 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
281 Value page_to_free_size_value;
282 page_to_free_size_value.SetValueType(Value::eValueTypeScalar);
283 page_to_free_size_value.SetCompilerType(clang_uint64_type);
284
285 std::lock_guard<std::mutex> guard(m_get_queues_retbuffer_mutex);
286 if (m_get_queues_return_buffer_addr == LLDB_INVALID_ADDRESS) {
287 addr_t bufaddr = process_sp->AllocateMemory(
288 32, ePermissionsReadable | ePermissionsWritable, error);
289 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
290 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "
291 "current queues func call");
292 return return_value;
293 }
294 m_get_queues_return_buffer_addr = bufaddr;
295 }
296
297 ValueList argument_values;
298
299 return_buffer_ptr_value.GetScalar() = m_get_queues_return_buffer_addr;
300 argument_values.PushValue(return_buffer_ptr_value);
301
302 debug_value.GetScalar() = 0;
303 argument_values.PushValue(debug_value);
304
305 if (page_to_free != LLDB_INVALID_ADDRESS)
306 page_to_free_value.GetScalar() = page_to_free;
307 else
308 page_to_free_value.GetScalar() = 0;
309 argument_values.PushValue(page_to_free_value);
310
311 page_to_free_size_value.GetScalar() = page_to_free_size;
312 argument_values.PushValue(page_to_free_size_value);
313
314 addr_t args_addr = SetupGetQueuesFunction(thread, argument_values);
315
316 if (!m_get_queues_impl_code_up) {
317 error.SetErrorString(
318 "Unable to compile __introspection_dispatch_get_queues.");
319 return return_value;
320 }
321
322 FunctionCaller *get_queues_caller =
323 m_get_queues_impl_code_up->GetFunctionCaller();
324
325 if (get_queues_caller == nullptr) {
326 error.SetErrorString(
327 "Unable to get caller for call __introspection_dispatch_get_queues");
328 return return_value;
329 }
330
331 DiagnosticManager diagnostics;
332 ExecutionContext exe_ctx;
333 EvaluateExpressionOptions options;
334 options.SetUnwindOnError(true);
335 options.SetIgnoreBreakpoints(true);
336 options.SetStopOthers(true);
337 #if __has_feature(address_sanitizer)
338 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
339 #else
340 options.SetTimeout(std::chrono::milliseconds(500));
341 #endif
342 options.SetTryAllThreads(false);
343 options.SetIsForUtilityExpr(true);
344 thread.CalculateExecutionContext(exe_ctx);
345
346 ExpressionResults func_call_ret;
347 Value results;
348 func_call_ret = get_queues_caller->ExecuteFunction(
349 exe_ctx, &args_addr, options, diagnostics, results);
350 if (func_call_ret != eExpressionCompleted || !error.Success()) {
351 LLDB_LOGF(log,
352 "Unable to call introspection_get_dispatch_queues(), got "
353 "ExpressionResults %d, error contains %s",
354 func_call_ret, error.AsCString(""));
355 error.SetErrorString("Unable to call introspection_get_dispatch_queues() "
356 "for list of queues");
357 return return_value;
358 }
359
360 return_value.queues_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
361 m_get_queues_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);
362 if (!error.Success() ||
363 return_value.queues_buffer_ptr == LLDB_INVALID_ADDRESS) {
364 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
365 return return_value;
366 }
367
368 return_value.queues_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
369 m_get_queues_return_buffer_addr + 8, 8, 0, error);
370
371 if (!error.Success()) {
372 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
373 return return_value;
374 }
375
376 return_value.count = m_process->ReadUnsignedIntegerFromMemory(
377 m_get_queues_return_buffer_addr + 16, 8, 0, error);
378 if (!error.Success()) {
379 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
380 return return_value;
381 }
382
383 LLDB_LOGF(log,
384 "AppleGetQueuesHandler called "
385 "__introspection_dispatch_get_queues (page_to_free == "
386 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64
387 ", size %" PRId64 ", count = %" PRId64,
388 page_to_free, page_to_free_size, return_value.queues_buffer_ptr,
389 return_value.queues_buffer_size, return_value.count);
390
391 return return_value;
392 }
393