1 //===-- AppleGetThreadItemInfoHandler.cpp -------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "AppleGetThreadItemInfoHandler.h"
11 
12 // C Includes
13 // C++ Includes
14 // Other libraries and framework includes
15 // Project includes
16 
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/DeclCXX.h"
19 
20 #include "lldb/Core/ConstString.h"
21 #include "lldb/Core/Log.h"
22 #include "lldb/Core/Module.h"
23 #include "lldb/Core/StreamString.h"
24 #include "lldb/Core/Value.h"
25 #include "lldb/Expression/ClangExpression.h"
26 #include "lldb/Expression/ClangFunction.h"
27 #include "lldb/Expression/ClangUtilityFunction.h"
28 #include "lldb/Symbol/ClangASTContext.h"
29 #include "lldb/Symbol/Symbol.h"
30 #include "lldb/Target/ExecutionContext.h"
31 #include "lldb/Target/Process.h"
32 #include "lldb/Target/Target.h"
33 #include "lldb/Target/Thread.h"
34 
35 using namespace lldb;
36 using namespace lldb_private;
37 
38 const char *AppleGetThreadItemInfoHandler::g_get_thread_item_info_function_name = "__lldb_backtrace_recording_get_thread_item_info";
39 const char *AppleGetThreadItemInfoHandler::g_get_thread_item_info_function_code = "                                  \n\
40 extern \"C\"                                                                                                    \n\
41 {                                                                                                               \n\
42     /*                                                                                                          \n\
43      * mach defines                                                                                             \n\
44      */                                                                                                         \n\
45                                                                                                                 \n\
46     typedef unsigned int uint32_t;                                                                              \n\
47     typedef unsigned long long uint64_t;                                                                        \n\
48     typedef uint32_t mach_port_t;                                                                               \n\
49     typedef mach_port_t vm_map_t;                                                                               \n\
50     typedef int kern_return_t;                                                                                  \n\
51     typedef uint64_t mach_vm_address_t;                                                                         \n\
52     typedef uint64_t mach_vm_size_t;                                                                            \n\
53                                                                                                                 \n\
54     mach_port_t mach_task_self ();                                                                              \n\
55     kern_return_t mach_vm_deallocate (vm_map_t target, mach_vm_address_t address, mach_vm_size_t size);         \n\
56                                                                                                                 \n\
57     typedef void *pthread_t;                                                                                    \n\
58     extern int printf(const char *format, ...);                                                                 \n\
59     extern pthread_t pthread_self(void);                                                                        \n\
60                                                                                                                 \n\
61     /*                                                                                                          \n\
62      * libBacktraceRecording defines                                                                            \n\
63      */                                                                                                         \n\
64                                                                                                                 \n\
65     typedef uint32_t queue_list_scope_t;                                                                        \n\
66     typedef void *dispatch_queue_t;                                                                             \n\
67     typedef void *introspection_dispatch_queue_info_t;                                                          \n\
68     typedef void *introspection_dispatch_item_info_ref;                                                         \n\
69                                                                                                                 \n\
70     extern void __introspection_dispatch_thread_get_item_info (uint64_t  thread_id,                             \n\
71                                                  introspection_dispatch_item_info_ref *returned_queues_buffer,  \n\
72                                                  uint64_t *returned_queues_buffer_size);                        \n\
73                                                                                                                 \n\
74     /*                                                                                                          \n\
75      * return type define                                                                                       \n\
76      */                                                                                                         \n\
77                                                                                                                 \n\
78     struct get_thread_item_info_return_values                                                                      \n\
79     {                                                                                                           \n\
80         uint64_t item_info_buffer_ptr;    /* the address of the items buffer from libBacktraceRecording */  \n\
81         uint64_t item_info_buffer_size;   /* the size of the items buffer from libBacktraceRecording */     \n\
82     };                                                                                                          \n\
83                                                                                                                 \n\
84     void  __lldb_backtrace_recording_get_thread_item_info                                                          \n\
85                                                (struct get_thread_item_info_return_values *return_buffer,          \n\
86                                                 int debug,                                                      \n\
87                                                 uint64_t thread_id,                                             \n\
88                                                 void *page_to_free,                                             \n\
89                                                 uint64_t page_to_free_size)                                     \n\
90 {                                                                                                               \n\
91     void *pthread_id = pthread_self ();                                                                         \n\
92     if (debug)                                                                                                  \n\
93       printf (\"entering get_thread_item_info with args return_buffer == %p, debug == %d, thread id == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, (uint64_t) thread_id, page_to_free, page_to_free_size); \n\
94     if (page_to_free != 0)                                                                                      \n\
95     {                                                                                                           \n\
96         mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\
97     }                                                                                                           \n\
98                                                                                                                 \n\
99     __introspection_dispatch_thread_get_item_info (thread_id,                                                  \n\
100                                                   (void**)&return_buffer->item_info_buffer_ptr,                 \n\
101                                                   &return_buffer->item_info_buffer_size);                       \n\
102 }                                                                                                               \n\
103 }                                                                                                               \n\
104 ";
105 
106 AppleGetThreadItemInfoHandler::AppleGetThreadItemInfoHandler (Process *process) :
107     m_process (process),
108     m_get_thread_item_info_function (),
109     m_get_thread_item_info_impl_code (),
110     m_get_thread_item_info_function_mutex(),
111     m_get_thread_item_info_return_buffer_addr (LLDB_INVALID_ADDRESS),
112     m_get_thread_item_info_retbuffer_mutex()
113 {
114 }
115 
116 AppleGetThreadItemInfoHandler::~AppleGetThreadItemInfoHandler ()
117 {
118 }
119 
120 void
121 AppleGetThreadItemInfoHandler::Detach ()
122 {
123 
124     if (m_process && m_process->IsAlive() && m_get_thread_item_info_return_buffer_addr != LLDB_INVALID_ADDRESS)
125     {
126         Mutex::Locker locker;
127         locker.TryLock (m_get_thread_item_info_retbuffer_mutex);  // Even if we don't get the lock, deallocate the buffer
128         m_process->DeallocateMemory (m_get_thread_item_info_return_buffer_addr);
129     }
130 }
131 
132 // Compile our __lldb_backtrace_recording_get_thread_item_info() function (from the
133 // source above in g_get_thread_item_info_function_code) if we don't find that function in the inferior
134 // already with USE_BUILTIN_FUNCTION defined.  (e.g. this would be the case for testing.)
135 //
136 // Insert the __lldb_backtrace_recording_get_thread_item_info into the inferior process if needed.
137 //
138 // Write the get_thread_item_info_arglist into the inferior's memory space to prepare for the call.
139 //
140 // Returns the address of the arguments written down in the inferior process, which can be used to
141 // make the function call.
142 
143 lldb::addr_t
144 AppleGetThreadItemInfoHandler::SetupGetThreadItemInfoFunction (Thread &thread, ValueList &get_thread_item_info_arglist)
145 {
146     ExecutionContext exe_ctx (thread.shared_from_this());
147     Address impl_code_address;
148     StreamString errors;
149     Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_SYSTEM_RUNTIME));
150     lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
151 
152     // Scope for mutex locker:
153     {
154         Mutex::Locker locker(m_get_thread_item_info_function_mutex);
155 
156         // First stage is to make the ClangUtility to hold our injected function:
157 
158 #define USE_BUILTIN_FUNCTION 0  // Define this to 1 and we will use the get_implementation function found in the target.
159                                 // This is useful for debugging additions to the get_impl function 'cause you don't have
160                                 // to bother with string-ifying the code into g_get_thread_item_info_function_code.
161 
162         if (USE_BUILTIN_FUNCTION)
163         {
164             ConstString our_utility_function_name("__lldb_backtrace_recording_get_thread_item_info");
165             SymbolContextList sc_list;
166 
167             exe_ctx.GetTargetRef().GetImages().FindSymbolsWithNameAndType (our_utility_function_name, eSymbolTypeCode, sc_list);
168             if (sc_list.GetSize() == 1)
169             {
170                 SymbolContext sc;
171                 sc_list.GetContextAtIndex(0, sc);
172                 if (sc.symbol != NULL)
173                     impl_code_address = sc.symbol->GetAddress();
174 
175                 //lldb::addr_t addr = impl_code_address.GetOpcodeLoadAddress (exe_ctx.GetTargetPtr());
176                 //printf ("Getting address for our_utility_function: 0x%" PRIx64 ".\n", addr);
177             }
178             else
179             {
180                 //printf ("Could not find queues introspection function address.\n");
181                 return args_addr;
182             }
183         }
184         else if (!m_get_thread_item_info_impl_code.get())
185         {
186             if (g_get_thread_item_info_function_code != NULL)
187             {
188                 m_get_thread_item_info_impl_code.reset (new ClangUtilityFunction (g_get_thread_item_info_function_code,
189                                                              g_get_thread_item_info_function_name));
190                 if (!m_get_thread_item_info_impl_code->Install(errors, exe_ctx))
191                 {
192                     if (log)
193                         log->Printf ("Failed to install get-thread-item-info introspection: %s.", errors.GetData());
194                     m_get_thread_item_info_impl_code.reset();
195                     return args_addr;
196                 }
197             }
198             else
199             {
200                 if (log)
201                     log->Printf("No get-thread-item-info introspection code found.");
202                 errors.Printf ("No get-thread-item-info introspection code found.");
203                 return LLDB_INVALID_ADDRESS;
204             }
205 
206             impl_code_address.Clear();
207             impl_code_address.SetOffset(m_get_thread_item_info_impl_code->StartAddress());
208         }
209         else
210         {
211             impl_code_address.Clear();
212             impl_code_address.SetOffset(m_get_thread_item_info_impl_code->StartAddress());
213         }
214 
215         // Next make the runner function for our implementation utility function.
216         if (!m_get_thread_item_info_function.get())
217         {
218             ClangASTContext *clang_ast_context = thread.GetProcess()->GetTarget().GetScratchClangASTContext();
219             ClangASTType get_thread_item_info_return_type = clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
220             m_get_thread_item_info_function.reset(new ClangFunction (thread,
221                                                      get_thread_item_info_return_type,
222                                                      impl_code_address,
223                                                      get_thread_item_info_arglist));
224 
225             errors.Clear();
226             unsigned num_errors = m_get_thread_item_info_function->CompileFunction(errors);
227             if (num_errors)
228             {
229                 if (log)
230                     log->Printf ("Error compiling get-thread-item-info function: \"%s\".", errors.GetData());
231                 return args_addr;
232             }
233 
234             errors.Clear();
235             if (!m_get_thread_item_info_function->WriteFunctionWrapper(exe_ctx, errors))
236             {
237                 if (log)
238                     log->Printf ("Error Inserting get-thread-item-info function: \"%s\".", errors.GetData());
239                 return args_addr;
240             }
241         }
242     }
243 
244     errors.Clear();
245 
246     // Now write down the argument values for this particular call.  This looks like it might be a race condition
247     // if other threads were calling into here, but actually it isn't because we allocate a new args structure for
248     // this call by passing args_addr = LLDB_INVALID_ADDRESS...
249 
250     if (!m_get_thread_item_info_function->WriteFunctionArguments (exe_ctx, args_addr, impl_code_address, get_thread_item_info_arglist, errors))
251     {
252         if (log)
253             log->Printf ("Error writing get-thread-item-info function arguments: \"%s\".", errors.GetData());
254         return args_addr;
255     }
256 
257     return args_addr;
258 }
259 
260 AppleGetThreadItemInfoHandler::GetThreadItemInfoReturnInfo
261 AppleGetThreadItemInfoHandler::GetThreadItemInfo (Thread &thread, tid_t thread_id, addr_t page_to_free, uint64_t page_to_free_size, Error &error)
262 {
263     lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
264     ProcessSP process_sp (thread.CalculateProcess());
265     TargetSP target_sp (thread.CalculateTarget());
266     ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
267     Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_SYSTEM_RUNTIME));
268 
269     GetThreadItemInfoReturnInfo return_value;
270     return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
271     return_value.item_buffer_size = 0;
272 
273     error.Clear();
274 
275     // Set up the arguments for a call to
276 
277     // struct get_thread_item_info_return_values
278     // {
279     //     uint64_t item_info_buffer_ptr;    /* the address of the items buffer from libBacktraceRecording */
280     //     uint64_t item_info_buffer_size;   /* the size of the items buffer from libBacktraceRecording */
281     // };
282     //
283     // void  __lldb_backtrace_recording_get_thread_item_info
284     //                                            (struct get_thread_item_info_return_values *return_buffer,
285     //                                             int debug,
286     //                                             void *page_to_free,
287     //                                             uint64_t page_to_free_size)
288 
289     // Where the return_buffer argument points to a 24 byte region of memory already allocated by lldb in
290     // the inferior process.
291 
292     ClangASTType clang_void_ptr_type = clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
293     Value return_buffer_ptr_value;
294     return_buffer_ptr_value.SetValueType (Value::eValueTypeScalar);
295     return_buffer_ptr_value.SetClangType (clang_void_ptr_type);
296 
297     ClangASTType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt);
298     Value debug_value;
299     debug_value.SetValueType (Value::eValueTypeScalar);
300     debug_value.SetClangType (clang_int_type);
301 
302     ClangASTType clang_uint64_type = clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
303     Value thread_id_value;
304     thread_id_value.SetValueType (Value::eValueTypeScalar);
305     thread_id_value.SetClangType (clang_uint64_type);
306 
307     Value page_to_free_value;
308     page_to_free_value.SetValueType (Value::eValueTypeScalar);
309     page_to_free_value.SetClangType (clang_void_ptr_type);
310 
311     Value page_to_free_size_value;
312     page_to_free_size_value.SetValueType (Value::eValueTypeScalar);
313     page_to_free_size_value.SetClangType (clang_uint64_type);
314 
315 
316     Mutex::Locker locker(m_get_thread_item_info_retbuffer_mutex);
317     if (m_get_thread_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS)
318     {
319         addr_t bufaddr = process_sp->AllocateMemory (32, ePermissionsReadable | ePermissionsWritable, error);
320         if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS)
321         {
322             if (log)
323                 log->Printf ("Failed to allocate memory for return buffer for get current queues func call");
324             return return_value;
325         }
326         m_get_thread_item_info_return_buffer_addr = bufaddr;
327     }
328 
329     ValueList argument_values;
330 
331     return_buffer_ptr_value.GetScalar() = m_get_thread_item_info_return_buffer_addr;
332     argument_values.PushValue (return_buffer_ptr_value);
333 
334     debug_value.GetScalar() = 0;
335     argument_values.PushValue (debug_value);
336 
337     thread_id_value.GetScalar() = thread_id;
338     argument_values.PushValue (thread_id_value);
339 
340     if (page_to_free != LLDB_INVALID_ADDRESS)
341         page_to_free_value.GetScalar() = page_to_free;
342     else
343         page_to_free_value.GetScalar() = 0;
344     argument_values.PushValue (page_to_free_value);
345 
346     page_to_free_size_value.GetScalar() = page_to_free_size;
347     argument_values.PushValue (page_to_free_size_value);
348 
349     addr_t args_addr = SetupGetThreadItemInfoFunction (thread, argument_values);
350 
351     StreamString errors;
352     ExecutionContext exe_ctx;
353     EvaluateExpressionOptions options;
354     options.SetUnwindOnError (true);
355     options.SetIgnoreBreakpoints (true);
356     options.SetStopOthers (true);
357     thread.CalculateExecutionContext (exe_ctx);
358 
359     if (m_get_thread_item_info_function == NULL)
360     {
361         error.SetErrorString ("Unable to compile function to call __introspection_dispatch_thread_get_item_info");
362         return return_value;
363     }
364 
365 
366     ExecutionResults func_call_ret;
367     Value results;
368     func_call_ret =  m_get_thread_item_info_function->ExecuteFunction (exe_ctx, &args_addr, options, errors, results);
369     if (func_call_ret != eExecutionCompleted || !error.Success())
370     {
371         if (log)
372             log->Printf ("Unable to call __introspection_dispatch_thread_get_item_info(), got ExecutionResults %d, error contains %s", func_call_ret, error.AsCString(""));
373         error.SetErrorString ("Unable to call __introspection_dispatch_thread_get_item_info() for list of queues");
374         return return_value;
375     }
376 
377     return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory (m_get_thread_item_info_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);
378     if (!error.Success() || return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS)
379     {
380         return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
381         return return_value;
382     }
383 
384     return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory (m_get_thread_item_info_return_buffer_addr + 8, 8, 0, error);
385 
386     if (!error.Success())
387     {
388         return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
389         return return_value;
390     }
391 
392     if (log)
393         log->Printf ("AppleGetThreadItemInfoHandler called __introspection_dispatch_thread_get_item_info (page_to_free == 0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64 ", size %" PRId64, page_to_free, page_to_free_size, return_value.item_buffer_ptr, return_value.item_buffer_size);
394 
395     return return_value;
396 }
397