1 //===-- DynamicLoaderMacOS.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 "lldb/Breakpoint/StoppointCallbackContext.h"
11 #include "lldb/Core/Debugger.h"
12 #include "lldb/Core/Log.h"
13 #include "lldb/Core/Module.h"
14 #include "lldb/Core/PluginManager.h"
15 #include "lldb/Core/Section.h"
16 #include "lldb/Core/State.h"
17 #include "lldb/Symbol/ClangASTContext.h"
18 #include "lldb/Symbol/ObjectFile.h"
19 #include "lldb/Symbol/SymbolVendor.h"
20 #include "lldb/Target/ABI.h"
21 #include "lldb/Target/StackFrame.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Target/Thread.h"
24 
25 #include "DynamicLoaderDarwin.h"
26 #include "DynamicLoaderMacOS.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 
31 //----------------------------------------------------------------------
32 // Create an instance of this class. This function is filled into
33 // the plugin info class that gets handed out by the plugin factory and
34 // allows the lldb to instantiate an instance of this class.
35 //----------------------------------------------------------------------
36 DynamicLoader *DynamicLoaderMacOS::CreateInstance(Process *process,
37                                                   bool force) {
38   bool create = force;
39   if (!create) {
40     create = true;
41     Module *exe_module = process->GetTarget().GetExecutableModulePointer();
42     if (exe_module) {
43       ObjectFile *object_file = exe_module->GetObjectFile();
44       if (object_file) {
45         create = (object_file->GetStrata() == ObjectFile::eStrataUser);
46       }
47     }
48 
49     if (create) {
50       const llvm::Triple &triple_ref =
51           process->GetTarget().GetArchitecture().GetTriple();
52       switch (triple_ref.getOS()) {
53       case llvm::Triple::Darwin:
54       case llvm::Triple::MacOSX:
55       case llvm::Triple::IOS:
56       case llvm::Triple::TvOS:
57       case llvm::Triple::WatchOS:
58         create = triple_ref.getVendor() == llvm::Triple::Apple;
59         break;
60       default:
61         create = false;
62         break;
63       }
64     }
65   }
66 
67   if (UseDYLDSPI(process) == false) {
68     create = false;
69   }
70 
71   if (create)
72     return new DynamicLoaderMacOS(process);
73   return NULL;
74 }
75 
76 //----------------------------------------------------------------------
77 // Constructor
78 //----------------------------------------------------------------------
79 DynamicLoaderMacOS::DynamicLoaderMacOS(Process *process)
80     : DynamicLoaderDarwin(process), m_image_infos_stop_id(UINT32_MAX),
81       m_break_id(LLDB_INVALID_BREAK_ID), m_mutex() {}
82 
83 //----------------------------------------------------------------------
84 // Destructor
85 //----------------------------------------------------------------------
86 DynamicLoaderMacOS::~DynamicLoaderMacOS() {
87   if (LLDB_BREAK_ID_IS_VALID(m_break_id))
88     m_process->GetTarget().RemoveBreakpointByID(m_break_id);
89 }
90 
91 bool DynamicLoaderMacOS::ProcessDidExec() {
92   std::lock_guard<std::recursive_mutex> baseclass_guard(GetMutex());
93   bool did_exec = false;
94   if (m_process) {
95     // If we are stopped after an exec, we will have only one thread...
96     if (m_process->GetThreadList().GetSize() == 1) {
97       // See if we are stopped at '_dyld_start'
98       ThreadSP thread_sp(m_process->GetThreadList().GetThreadAtIndex(0));
99       if (thread_sp) {
100         lldb::StackFrameSP frame_sp(thread_sp->GetStackFrameAtIndex(0));
101         if (frame_sp) {
102           const Symbol *symbol =
103               frame_sp->GetSymbolContext(eSymbolContextSymbol).symbol;
104           if (symbol) {
105             if (symbol->GetName() == ConstString("_dyld_start"))
106               did_exec = true;
107           }
108         }
109       }
110     }
111   }
112 
113   if (did_exec) {
114     m_libpthread_module_wp.reset();
115     m_pthread_getspecific_addr.Clear();
116   }
117   return did_exec;
118 }
119 
120 //----------------------------------------------------------------------
121 // Clear out the state of this class.
122 //----------------------------------------------------------------------
123 void DynamicLoaderMacOS::DoClear() {
124   std::lock_guard<std::recursive_mutex> guard(m_mutex);
125 
126   if (LLDB_BREAK_ID_IS_VALID(m_break_id))
127     m_process->GetTarget().RemoveBreakpointByID(m_break_id);
128 
129   m_break_id = LLDB_INVALID_BREAK_ID;
130 }
131 
132 //----------------------------------------------------------------------
133 // Check if we have found DYLD yet
134 //----------------------------------------------------------------------
135 bool DynamicLoaderMacOS::DidSetNotificationBreakpoint() {
136   return LLDB_BREAK_ID_IS_VALID(m_break_id);
137 }
138 
139 void DynamicLoaderMacOS::ClearNotificationBreakpoint() {
140   if (LLDB_BREAK_ID_IS_VALID(m_break_id)) {
141     m_process->GetTarget().RemoveBreakpointByID(m_break_id);
142   }
143 }
144 
145 //----------------------------------------------------------------------
146 // Try and figure out where dyld is by first asking the Process
147 // if it knows (which currently calls down in the lldb::Process
148 // to get the DYLD info (available on SnowLeopard only). If that fails,
149 // then check in the default addresses.
150 //----------------------------------------------------------------------
151 void DynamicLoaderMacOS::DoInitialImageFetch() {
152   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
153 
154   StructuredData::ObjectSP all_image_info_json_sp(
155       m_process->GetLoadedDynamicLibrariesInfos());
156   ImageInfo::collection image_infos;
157   if (all_image_info_json_sp.get() &&
158       all_image_info_json_sp->GetAsDictionary() &&
159       all_image_info_json_sp->GetAsDictionary()->HasKey("images") &&
160       all_image_info_json_sp->GetAsDictionary()
161           ->GetValueForKey("images")
162           ->GetAsArray()) {
163     if (JSONImageInformationIntoImageInfo(all_image_info_json_sp,
164                                           image_infos)) {
165       if (log)
166         log->Printf("Initial module fetch:  Adding %" PRId64 " modules.\n",
167                     (uint64_t)image_infos.size());
168 
169       UpdateSpecialBinariesFromNewImageInfos(image_infos);
170       AddModulesUsingImageInfos(image_infos);
171     }
172   }
173 
174   m_dyld_image_infos_stop_id = m_process->GetStopID();
175 }
176 
177 bool DynamicLoaderMacOS::NeedToDoInitialImageFetch() { return true; }
178 
179 //----------------------------------------------------------------------
180 // Static callback function that gets called when our DYLD notification
181 // breakpoint gets hit. We update all of our image infos and then
182 // let our super class DynamicLoader class decide if we should stop
183 // or not (based on global preference).
184 //----------------------------------------------------------------------
185 bool DynamicLoaderMacOS::NotifyBreakpointHit(void *baton,
186                                              StoppointCallbackContext *context,
187                                              lldb::user_id_t break_id,
188                                              lldb::user_id_t break_loc_id) {
189   // Let the event know that the images have changed
190   // DYLD passes three arguments to the notification breakpoint.
191   // Arg1: enum dyld_notify_mode mode - 0 = adding, 1 = removing, 2 = remove all
192   // Arg2: unsigned long icount        - Number of shared libraries
193   // added/removed
194   // Arg3: uint64_t mach_headers[]     - Array of load addresses of binaries
195   // added/removed
196 
197   DynamicLoaderMacOS *dyld_instance = (DynamicLoaderMacOS *)baton;
198 
199   ExecutionContext exe_ctx(context->exe_ctx_ref);
200   Process *process = exe_ctx.GetProcessPtr();
201 
202   // This is a sanity check just in case this dyld_instance is an old dyld
203   // plugin's breakpoint still lying around.
204   if (process != dyld_instance->m_process)
205     return false;
206 
207   if (dyld_instance->m_image_infos_stop_id != UINT32_MAX &&
208       process->GetStopID() < dyld_instance->m_image_infos_stop_id) {
209     return false;
210   }
211 
212   const lldb::ABISP &abi = process->GetABI();
213   if (abi) {
214     // Build up the value array to store the three arguments given above, then
215     // get the values from the ABI:
216 
217     ClangASTContext *clang_ast_context =
218         process->GetTarget().GetScratchClangASTContext();
219     ValueList argument_values;
220 
221     Value mode_value;    // enum dyld_notify_mode { dyld_notify_adding=0,
222                          // dyld_notify_removing=1, dyld_notify_remove_all=2 };
223     Value count_value;   // unsigned long count
224     Value headers_value; // uint64_t machHeaders[] (aka void*)
225 
226     CompilerType clang_void_ptr_type =
227         clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
228     CompilerType clang_uint32_type =
229         clang_ast_context->GetBuiltinTypeForEncodingAndBitSize(
230             lldb::eEncodingUint, 32);
231     CompilerType clang_uint64_type =
232         clang_ast_context->GetBuiltinTypeForEncodingAndBitSize(
233             lldb::eEncodingUint, 32);
234 
235     mode_value.SetValueType(Value::eValueTypeScalar);
236     mode_value.SetCompilerType(clang_uint32_type);
237 
238     if (process->GetTarget().GetArchitecture().GetAddressByteSize() == 4) {
239       count_value.SetValueType(Value::eValueTypeScalar);
240       count_value.SetCompilerType(clang_uint32_type);
241     } else {
242       count_value.SetValueType(Value::eValueTypeScalar);
243       count_value.SetCompilerType(clang_uint64_type);
244     }
245 
246     headers_value.SetValueType(Value::eValueTypeScalar);
247     headers_value.SetCompilerType(clang_void_ptr_type);
248 
249     argument_values.PushValue(mode_value);
250     argument_values.PushValue(count_value);
251     argument_values.PushValue(headers_value);
252 
253     if (abi->GetArgumentValues(exe_ctx.GetThreadRef(), argument_values)) {
254       uint32_t dyld_mode =
255           argument_values.GetValueAtIndex(0)->GetScalar().UInt(-1);
256       if (dyld_mode != static_cast<uint32_t>(-1)) {
257         // Okay the mode was right, now get the number of elements, and the
258         // array of new elements...
259         uint32_t image_infos_count =
260             argument_values.GetValueAtIndex(1)->GetScalar().UInt(-1);
261         if (image_infos_count != static_cast<uint32_t>(-1)) {
262           addr_t header_array =
263               argument_values.GetValueAtIndex(2)->GetScalar().ULongLong(-1);
264           if (header_array != static_cast<uint64_t>(-1)) {
265             std::vector<addr_t> image_load_addresses;
266             for (uint64_t i = 0; i < image_infos_count; i++) {
267               Error error;
268               addr_t addr = process->ReadUnsignedIntegerFromMemory(
269                   header_array + (8 * i), 8, LLDB_INVALID_ADDRESS, error);
270               if (addr != LLDB_INVALID_ADDRESS) {
271                 image_load_addresses.push_back(addr);
272               }
273             }
274             if (dyld_mode == 0) {
275               // dyld_notify_adding
276               dyld_instance->AddBinaries(image_load_addresses);
277             } else if (dyld_mode == 1) {
278               // dyld_notify_removing
279               dyld_instance->UnloadImages(image_load_addresses);
280             } else if (dyld_mode == 2) {
281               // dyld_notify_remove_all
282               dyld_instance->UnloadAllImages();
283             }
284           }
285         }
286       }
287     }
288   } else {
289     process->GetTarget().GetDebugger().GetAsyncErrorStream()->Printf(
290         "No ABI plugin located for triple %s -- shared libraries will not be "
291         "registered!\n",
292         process->GetTarget().GetArchitecture().GetTriple().getTriple().c_str());
293   }
294 
295   // Return true to stop the target, false to just let the target run
296   return dyld_instance->GetStopWhenImagesChange();
297 }
298 
299 void DynamicLoaderMacOS::AddBinaries(
300     const std::vector<lldb::addr_t> &load_addresses) {
301   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
302   ImageInfo::collection image_infos;
303 
304   if (log)
305     log->Printf("Adding %" PRId64 " modules.", (uint64_t)load_addresses.size());
306   StructuredData::ObjectSP binaries_info_sp =
307       m_process->GetLoadedDynamicLibrariesInfos(load_addresses);
308   if (binaries_info_sp.get() && binaries_info_sp->GetAsDictionary() &&
309       binaries_info_sp->GetAsDictionary()->HasKey("images") &&
310       binaries_info_sp->GetAsDictionary()
311           ->GetValueForKey("images")
312           ->GetAsArray() &&
313       binaries_info_sp->GetAsDictionary()
314               ->GetValueForKey("images")
315               ->GetAsArray()
316               ->GetSize() == load_addresses.size()) {
317     if (JSONImageInformationIntoImageInfo(binaries_info_sp, image_infos)) {
318       UpdateSpecialBinariesFromNewImageInfos(image_infos);
319       AddModulesUsingImageInfos(image_infos);
320     }
321     m_dyld_image_infos_stop_id = m_process->GetStopID();
322   }
323 }
324 
325 // Dump the _dyld_all_image_infos members and all current image infos
326 // that we have parsed to the file handle provided.
327 //----------------------------------------------------------------------
328 void DynamicLoaderMacOS::PutToLog(Log *log) const {
329   if (log == NULL)
330     return;
331 }
332 
333 bool DynamicLoaderMacOS::SetNotificationBreakpoint() {
334   if (m_break_id == LLDB_INVALID_BREAK_ID) {
335     ConstString g_symbol_name("_dyld_debugger_notification");
336     const Symbol *symbol = nullptr;
337     ModuleSP dyld_sp(GetDYLDModule());
338     if (dyld_sp) {
339       symbol = dyld_sp->FindFirstSymbolWithNameAndType(g_symbol_name,
340                                                        eSymbolTypeCode);
341     }
342     if (symbol &&
343         (symbol->ValueIsAddress() || symbol->GetAddressRef().IsValid())) {
344       addr_t symbol_address =
345           symbol->GetAddressRef().GetOpcodeLoadAddress(&m_process->GetTarget());
346       if (symbol_address != LLDB_INVALID_ADDRESS) {
347         bool internal = true;
348         bool hardware = false;
349         Breakpoint *breakpoint =
350             m_process->GetTarget()
351                 .CreateBreakpoint(symbol_address, internal, hardware)
352                 .get();
353         breakpoint->SetCallback(DynamicLoaderMacOS::NotifyBreakpointHit, this,
354                                 true);
355         breakpoint->SetBreakpointKind("shared-library-event");
356         m_break_id = breakpoint->GetID();
357       }
358     }
359   }
360   return m_break_id != LLDB_INVALID_BREAK_ID;
361 }
362 
363 addr_t
364 DynamicLoaderMacOS::GetDyldLockVariableAddressFromModule(Module *module) {
365   SymbolContext sc;
366   SymbolVendor *sym_vendor = module->GetSymbolVendor();
367   Target &target = m_process->GetTarget();
368   if (sym_vendor) {
369     Symtab *symtab = sym_vendor->GetSymtab();
370     if (symtab) {
371       std::vector<uint32_t> match_indexes;
372       ConstString g_symbol_name("_dyld_global_lock_held");
373       uint32_t num_matches = 0;
374       num_matches =
375           symtab->AppendSymbolIndexesWithName(g_symbol_name, match_indexes);
376       if (num_matches == 1) {
377         Symbol *symbol = symtab->SymbolAtIndex(match_indexes[0]);
378         if (symbol &&
379             (symbol->ValueIsAddress() || symbol->GetAddressRef().IsValid())) {
380           return symbol->GetAddressRef().GetOpcodeLoadAddress(&target);
381         }
382       }
383     }
384   }
385   return LLDB_INVALID_ADDRESS;
386 }
387 
388 //  Look for this symbol:
389 //
390 //  int __attribute__((visibility("hidden")))           _dyld_global_lock_held =
391 //  0;
392 //
393 //  in libdyld.dylib.
394 Error DynamicLoaderMacOS::CanLoadImage() {
395   Error error;
396   addr_t symbol_address = LLDB_INVALID_ADDRESS;
397   Target &target = m_process->GetTarget();
398   const ModuleList &target_modules = target.GetImages();
399   std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex());
400   const size_t num_modules = target_modules.GetSize();
401   ConstString g_libdyld_name("libdyld.dylib");
402 
403   // Find any modules named "libdyld.dylib" and look for the symbol there first
404   for (size_t i = 0; i < num_modules; i++) {
405     Module *module_pointer = target_modules.GetModulePointerAtIndexUnlocked(i);
406     if (module_pointer) {
407       if (module_pointer->GetFileSpec().GetFilename() == g_libdyld_name) {
408         symbol_address = GetDyldLockVariableAddressFromModule(module_pointer);
409         if (symbol_address != LLDB_INVALID_ADDRESS)
410           break;
411       }
412     }
413   }
414 
415   // Search through all modules looking for the symbol in them
416   if (symbol_address == LLDB_INVALID_ADDRESS) {
417     for (size_t i = 0; i < num_modules; i++) {
418       Module *module_pointer =
419           target_modules.GetModulePointerAtIndexUnlocked(i);
420       if (module_pointer) {
421         addr_t symbol_address =
422             GetDyldLockVariableAddressFromModule(module_pointer);
423         if (symbol_address != LLDB_INVALID_ADDRESS)
424           break;
425       }
426     }
427   }
428 
429   // Default assumption is that it is OK to load images.
430   // Only say that we cannot load images if we find the symbol in libdyld and it
431   // indicates that
432   // we cannot.
433 
434   if (symbol_address != LLDB_INVALID_ADDRESS) {
435     {
436       int lock_held =
437           m_process->ReadUnsignedIntegerFromMemory(symbol_address, 4, 0, error);
438       if (lock_held != 0) {
439         error.SetErrorToGenericError();
440       }
441     }
442   } else {
443     // If we were unable to find _dyld_global_lock_held in any modules, or it is
444     // not loaded into
445     // memory yet, we may be at process startup (sitting at _dyld_start) - so we
446     // should not allow
447     // dlopen calls.
448     error.SetErrorToGenericError();
449   }
450   return error;
451 }
452 
453 bool DynamicLoaderMacOS::GetSharedCacheInformation(
454     lldb::addr_t &base_address, UUID &uuid, LazyBool &using_shared_cache,
455     LazyBool &private_shared_cache) {
456   base_address = LLDB_INVALID_ADDRESS;
457   uuid.Clear();
458   using_shared_cache = eLazyBoolCalculate;
459   private_shared_cache = eLazyBoolCalculate;
460 
461   if (m_process) {
462     StructuredData::ObjectSP info = m_process->GetSharedCacheInfo();
463     StructuredData::Dictionary *info_dict = nullptr;
464     if (info.get() && info->GetAsDictionary()) {
465       info_dict = info->GetAsDictionary();
466     }
467 
468     // {"shared_cache_base_address":140735683125248,"shared_cache_uuid":"DDB8D70C-C9A2-3561-B2C8-BE48A4F33F96","no_shared_cache":false,"shared_cache_private_cache":false}
469 
470     if (info_dict && info_dict->HasKey("shared_cache_uuid") &&
471         info_dict->HasKey("no_shared_cache") &&
472         info_dict->HasKey("shared_cache_base_address")) {
473       base_address = info_dict->GetValueForKey("shared_cache_base_address")
474                          ->GetIntegerValue(LLDB_INVALID_ADDRESS);
475       std::string uuid_str = info_dict->GetValueForKey("shared_cache_uuid")
476                                  ->GetStringValue()
477                                  .c_str();
478       if (!uuid_str.empty())
479         uuid.SetFromCString(uuid_str.c_str());
480       if (info_dict->GetValueForKey("no_shared_cache")->GetBooleanValue() ==
481           false)
482         using_shared_cache = eLazyBoolYes;
483       else
484         using_shared_cache = eLazyBoolNo;
485       if (info_dict->GetValueForKey("shared_cache_private_cache")
486               ->GetBooleanValue())
487         private_shared_cache = eLazyBoolYes;
488       else
489         private_shared_cache = eLazyBoolNo;
490 
491       return true;
492     }
493   }
494   return false;
495 }
496 
497 void DynamicLoaderMacOS::Initialize() {
498   PluginManager::RegisterPlugin(GetPluginNameStatic(),
499                                 GetPluginDescriptionStatic(), CreateInstance);
500 }
501 
502 void DynamicLoaderMacOS::Terminate() {
503   PluginManager::UnregisterPlugin(CreateInstance);
504 }
505 
506 lldb_private::ConstString DynamicLoaderMacOS::GetPluginNameStatic() {
507   static ConstString g_name("macos-dyld");
508   return g_name;
509 }
510 
511 const char *DynamicLoaderMacOS::GetPluginDescriptionStatic() {
512   return "Dynamic loader plug-in that watches for shared library loads/unloads "
513          "in MacOSX user processes.";
514 }
515 
516 //------------------------------------------------------------------
517 // PluginInterface protocol
518 //------------------------------------------------------------------
519 lldb_private::ConstString DynamicLoaderMacOS::GetPluginName() {
520   return GetPluginNameStatic();
521 }
522 
523 uint32_t DynamicLoaderMacOS::GetPluginVersion() { return 1; }
524