1 //===-- DynamicLoaderPOSIXDYLD.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 // Main header include
10 #include "DynamicLoaderPOSIXDYLD.h"
11 
12 #include "lldb/Breakpoint/BreakpointLocation.h"
13 #include "lldb/Core/Module.h"
14 #include "lldb/Core/ModuleSpec.h"
15 #include "lldb/Core/PluginManager.h"
16 #include "lldb/Core/Section.h"
17 #include "lldb/Symbol/Function.h"
18 #include "lldb/Symbol/ObjectFile.h"
19 #include "lldb/Target/MemoryRegionInfo.h"
20 #include "lldb/Target/Platform.h"
21 #include "lldb/Target/Target.h"
22 #include "lldb/Target/Thread.h"
23 #include "lldb/Target/ThreadPlanRunToAddress.h"
24 #include "lldb/Utility/Log.h"
25 #include "lldb/Utility/ProcessInfo.h"
26 
27 #include <memory>
28 
29 using namespace lldb;
30 using namespace lldb_private;
31 
32 LLDB_PLUGIN_DEFINE_ADV(DynamicLoaderPOSIXDYLD, DynamicLoaderPosixDYLD)
33 
34 void DynamicLoaderPOSIXDYLD::Initialize() {
35   PluginManager::RegisterPlugin(GetPluginNameStatic(),
36                                 GetPluginDescriptionStatic(), CreateInstance);
37 }
38 
39 void DynamicLoaderPOSIXDYLD::Terminate() {}
40 
41 lldb_private::ConstString DynamicLoaderPOSIXDYLD::GetPluginName() {
42   return GetPluginNameStatic();
43 }
44 
45 lldb_private::ConstString DynamicLoaderPOSIXDYLD::GetPluginNameStatic() {
46   static ConstString g_name("linux-dyld");
47   return g_name;
48 }
49 
50 const char *DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic() {
51   return "Dynamic loader plug-in that watches for shared library "
52          "loads/unloads in POSIX processes.";
53 }
54 
55 uint32_t DynamicLoaderPOSIXDYLD::GetPluginVersion() { return 1; }
56 
57 DynamicLoader *DynamicLoaderPOSIXDYLD::CreateInstance(Process *process,
58                                                       bool force) {
59   bool create = force;
60   if (!create) {
61     const llvm::Triple &triple_ref =
62         process->GetTarget().GetArchitecture().GetTriple();
63     if (triple_ref.getOS() == llvm::Triple::FreeBSD ||
64         triple_ref.getOS() == llvm::Triple::Linux ||
65         triple_ref.getOS() == llvm::Triple::NetBSD)
66       create = true;
67   }
68 
69   if (create)
70     return new DynamicLoaderPOSIXDYLD(process);
71   return nullptr;
72 }
73 
74 DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process)
75     : DynamicLoader(process), m_rendezvous(process),
76       m_load_offset(LLDB_INVALID_ADDRESS), m_entry_point(LLDB_INVALID_ADDRESS),
77       m_auxv(), m_dyld_bid(LLDB_INVALID_BREAK_ID),
78       m_vdso_base(LLDB_INVALID_ADDRESS),
79       m_interpreter_base(LLDB_INVALID_ADDRESS) {}
80 
81 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD() {
82   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
83     m_process->GetTarget().RemoveBreakpointByID(m_dyld_bid);
84     m_dyld_bid = LLDB_INVALID_BREAK_ID;
85   }
86 }
87 
88 void DynamicLoaderPOSIXDYLD::DidAttach() {
89   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
90   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64, __FUNCTION__,
91             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
92   m_auxv = std::make_unique<AuxVector>(m_process->GetAuxvData());
93 
94   LLDB_LOGF(
95       log, "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " reloaded auxv data",
96       __FUNCTION__, m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
97 
98   // ask the process if it can load any of its own modules
99   auto error = m_process->LoadModules();
100   LLDB_LOG_ERROR(log, std::move(error), "Couldn't load modules: {0}");
101 
102   ModuleSP executable_sp = GetTargetExecutable();
103   ResolveExecutableModule(executable_sp);
104 
105   // find the main process load offset
106   addr_t load_offset = ComputeLoadOffset();
107   LLDB_LOGF(log,
108             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
109             " executable '%s', load_offset 0x%" PRIx64,
110             __FUNCTION__,
111             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
112             executable_sp ? executable_sp->GetFileSpec().GetPath().c_str()
113                           : "<null executable>",
114             load_offset);
115 
116   EvalSpecialModulesStatus();
117 
118   // if we dont have a load address we cant re-base
119   bool rebase_exec = load_offset != LLDB_INVALID_ADDRESS;
120 
121   // if we have a valid executable
122   if (executable_sp.get()) {
123     lldb_private::ObjectFile *obj = executable_sp->GetObjectFile();
124     if (obj) {
125       // don't rebase if the module already has a load address
126       Target &target = m_process->GetTarget();
127       Address addr = obj->GetImageInfoAddress(&target);
128       if (addr.GetLoadAddress(&target) != LLDB_INVALID_ADDRESS)
129         rebase_exec = false;
130     }
131   } else {
132     // no executable, nothing to re-base
133     rebase_exec = false;
134   }
135 
136   // if the target executable should be re-based
137   if (rebase_exec) {
138     ModuleList module_list;
139 
140     module_list.Append(executable_sp);
141     LLDB_LOGF(log,
142               "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
143               " added executable '%s' to module load list",
144               __FUNCTION__,
145               m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
146               executable_sp->GetFileSpec().GetPath().c_str());
147 
148     UpdateLoadedSections(executable_sp, LLDB_INVALID_ADDRESS, load_offset,
149                          true);
150 
151     LoadAllCurrentModules();
152 
153     m_process->GetTarget().ModulesDidLoad(module_list);
154     if (log) {
155       LLDB_LOGF(log,
156                 "DynamicLoaderPOSIXDYLD::%s told the target about the "
157                 "modules that loaded:",
158                 __FUNCTION__);
159       for (auto module_sp : module_list.Modules()) {
160         LLDB_LOGF(log, "-- [module] %s (pid %" PRIu64 ")",
161                   module_sp ? module_sp->GetFileSpec().GetPath().c_str()
162                             : "<null>",
163                   m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
164       }
165     }
166   }
167 
168   if (executable_sp.get()) {
169     if (!SetRendezvousBreakpoint()) {
170       // If we cannot establish rendezvous breakpoint right now we'll try again
171       // at entry point.
172       ProbeEntry();
173     }
174   }
175 }
176 
177 void DynamicLoaderPOSIXDYLD::DidLaunch() {
178   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
179   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s()", __FUNCTION__);
180 
181   ModuleSP executable;
182   addr_t load_offset;
183 
184   m_auxv = std::make_unique<AuxVector>(m_process->GetAuxvData());
185 
186   executable = GetTargetExecutable();
187   load_offset = ComputeLoadOffset();
188   EvalSpecialModulesStatus();
189 
190   if (executable.get() && load_offset != LLDB_INVALID_ADDRESS) {
191     ModuleList module_list;
192     module_list.Append(executable);
193     UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset, true);
194 
195     LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s about to call ProbeEntry()",
196               __FUNCTION__);
197 
198     if (!SetRendezvousBreakpoint()) {
199       // If we cannot establish rendezvous breakpoint right now we'll try again
200       // at entry point.
201       ProbeEntry();
202     }
203 
204     LoadVDSO();
205     m_process->GetTarget().ModulesDidLoad(module_list);
206   }
207 }
208 
209 Status DynamicLoaderPOSIXDYLD::CanLoadImage() { return Status(); }
210 
211 void DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module,
212                                                   addr_t link_map_addr,
213                                                   addr_t base_addr,
214                                                   bool base_addr_is_offset) {
215   m_loaded_modules[module] = link_map_addr;
216   UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
217 }
218 
219 void DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module) {
220   m_loaded_modules.erase(module);
221 
222   UnloadSectionsCommon(module);
223 }
224 
225 void DynamicLoaderPOSIXDYLD::ProbeEntry() {
226   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
227 
228   const addr_t entry = GetEntryPoint();
229   if (entry == LLDB_INVALID_ADDRESS) {
230     LLDB_LOGF(
231         log,
232         "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
233         " GetEntryPoint() returned no address, not setting entry breakpoint",
234         __FUNCTION__, m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
235     return;
236   }
237 
238   LLDB_LOGF(log,
239             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
240             " GetEntryPoint() returned address 0x%" PRIx64
241             ", setting entry breakpoint",
242             __FUNCTION__,
243             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID, entry);
244 
245   if (m_process) {
246     Breakpoint *const entry_break =
247         m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
248     entry_break->SetCallback(EntryBreakpointHit, this, true);
249     entry_break->SetBreakpointKind("shared-library-event");
250 
251     // Shoudn't hit this more than once.
252     entry_break->SetOneShot(true);
253   }
254 }
255 
256 // The runtime linker has run and initialized the rendezvous structure once the
257 // process has hit its entry point.  When we hit the corresponding breakpoint
258 // we interrogate the rendezvous structure to get the load addresses of all
259 // dependent modules for the process.  Similarly, we can discover the runtime
260 // linker function and setup a breakpoint to notify us of any dynamically
261 // loaded modules (via dlopen).
262 bool DynamicLoaderPOSIXDYLD::EntryBreakpointHit(
263     void *baton, StoppointCallbackContext *context, user_id_t break_id,
264     user_id_t break_loc_id) {
265   assert(baton && "null baton");
266   if (!baton)
267     return false;
268 
269   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
270   DynamicLoaderPOSIXDYLD *const dyld_instance =
271       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
272   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
273             __FUNCTION__,
274             dyld_instance->m_process ? dyld_instance->m_process->GetID()
275                                      : LLDB_INVALID_PROCESS_ID);
276 
277   // Disable the breakpoint --- if a stop happens right after this, which we've
278   // seen on occasion, we don't want the breakpoint stepping thread-plan logic
279   // to show a breakpoint instruction at the disassembled entry point to the
280   // program.  Disabling it prevents it.  (One-shot is not enough - one-shot
281   // removal logic only happens after the breakpoint goes public, which wasn't
282   // happening in our scenario).
283   if (dyld_instance->m_process) {
284     BreakpointSP breakpoint_sp =
285         dyld_instance->m_process->GetTarget().GetBreakpointByID(break_id);
286     if (breakpoint_sp) {
287       LLDB_LOGF(log,
288                 "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
289                 " disabling breakpoint id %" PRIu64,
290                 __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
291       breakpoint_sp->SetEnabled(false);
292     } else {
293       LLDB_LOGF(log,
294                 "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
295                 " failed to find breakpoint for breakpoint id %" PRIu64,
296                 __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
297     }
298   } else {
299     LLDB_LOGF(log,
300               "DynamicLoaderPOSIXDYLD::%s breakpoint id %" PRIu64
301               " no Process instance!  Cannot disable breakpoint",
302               __FUNCTION__, break_id);
303   }
304 
305   dyld_instance->LoadAllCurrentModules();
306   dyld_instance->SetRendezvousBreakpoint();
307   return false; // Continue running.
308 }
309 
310 bool DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() {
311   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
312   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
313     LLDB_LOG(log,
314              "Rendezvous breakpoint breakpoint id {0} for pid {1}"
315              "is already set.",
316              m_dyld_bid,
317              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
318     return true;
319   }
320 
321   addr_t break_addr;
322   Target &target = m_process->GetTarget();
323   BreakpointSP dyld_break;
324   if (m_rendezvous.IsValid()) {
325     break_addr = m_rendezvous.GetBreakAddress();
326     LLDB_LOG(log, "Setting rendezvous break address for pid {0} at {1:x}",
327              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
328              break_addr);
329     dyld_break = target.CreateBreakpoint(break_addr, true, false);
330   } else {
331     LLDB_LOG(log, "Rendezvous structure is not set up yet. "
332                   "Trying to locate rendezvous breakpoint in the interpreter "
333                   "by symbol name.");
334     ModuleSP interpreter = LoadInterpreterModule();
335     if (!interpreter) {
336       LLDB_LOG(log, "Can't find interpreter, rendezvous breakpoint isn't set.");
337       return false;
338     }
339 
340     // Function names from different dynamic loaders that are known to be used
341     // as rendezvous between the loader and debuggers.
342     static std::vector<std::string> DebugStateCandidates{
343         "_dl_debug_state", "rtld_db_dlactivity", "__dl_rtld_db_dlactivity",
344         "r_debug_state",   "_r_debug_state",     "_rtld_debug_state",
345     };
346 
347     FileSpecList containingModules;
348     containingModules.Append(interpreter->GetFileSpec());
349     dyld_break = target.CreateBreakpoint(
350         &containingModules, nullptr /* containingSourceFiles */,
351         DebugStateCandidates, eFunctionNameTypeFull, eLanguageTypeC,
352         0,           /* offset */
353         eLazyBoolNo, /* skip_prologue */
354         true,        /* internal */
355         false /* request_hardware */);
356   }
357 
358   if (dyld_break->GetNumResolvedLocations() != 1) {
359     LLDB_LOG(
360         log,
361         "Rendezvous breakpoint has abnormal number of"
362         " resolved locations ({0}) in pid {1}. It's supposed to be exactly 1.",
363         dyld_break->GetNumResolvedLocations(),
364         m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
365 
366     target.RemoveBreakpointByID(dyld_break->GetID());
367     return false;
368   }
369 
370   BreakpointLocationSP location = dyld_break->GetLocationAtIndex(0);
371   LLDB_LOG(log,
372            "Successfully set rendezvous breakpoint at address {0:x} "
373            "for pid {1}",
374            location->GetLoadAddress(),
375            m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
376 
377   dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
378   dyld_break->SetBreakpointKind("shared-library-event");
379   m_dyld_bid = dyld_break->GetID();
380   return true;
381 }
382 
383 bool DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(
384     void *baton, StoppointCallbackContext *context, user_id_t break_id,
385     user_id_t break_loc_id) {
386   assert(baton && "null baton");
387   if (!baton)
388     return false;
389 
390   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
391   DynamicLoaderPOSIXDYLD *const dyld_instance =
392       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
393   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
394             __FUNCTION__,
395             dyld_instance->m_process ? dyld_instance->m_process->GetID()
396                                      : LLDB_INVALID_PROCESS_ID);
397 
398   dyld_instance->RefreshModules();
399 
400   // Return true to stop the target, false to just let the target run.
401   const bool stop_when_images_change = dyld_instance->GetStopWhenImagesChange();
402   LLDB_LOGF(log,
403             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
404             " stop_when_images_change=%s",
405             __FUNCTION__,
406             dyld_instance->m_process ? dyld_instance->m_process->GetID()
407                                      : LLDB_INVALID_PROCESS_ID,
408             stop_when_images_change ? "true" : "false");
409   return stop_when_images_change;
410 }
411 
412 void DynamicLoaderPOSIXDYLD::RefreshModules() {
413   if (!m_rendezvous.Resolve())
414     return;
415 
416   DYLDRendezvous::iterator I;
417   DYLDRendezvous::iterator E;
418 
419   ModuleList &loaded_modules = m_process->GetTarget().GetImages();
420 
421   if (m_rendezvous.ModulesDidLoad()) {
422     ModuleList new_modules;
423 
424     E = m_rendezvous.loaded_end();
425     for (I = m_rendezvous.loaded_begin(); I != E; ++I) {
426       ModuleSP module_sp =
427           LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
428       if (module_sp.get()) {
429         loaded_modules.AppendIfNeeded(module_sp);
430         new_modules.Append(module_sp);
431       }
432     }
433     m_process->GetTarget().ModulesDidLoad(new_modules);
434   }
435 
436   if (m_rendezvous.ModulesDidUnload()) {
437     ModuleList old_modules;
438 
439     E = m_rendezvous.unloaded_end();
440     for (I = m_rendezvous.unloaded_begin(); I != E; ++I) {
441       ModuleSpec module_spec{I->file_spec};
442       ModuleSP module_sp = loaded_modules.FindFirstModule(module_spec);
443 
444       if (module_sp.get()) {
445         old_modules.Append(module_sp);
446         UnloadSections(module_sp);
447       }
448     }
449     loaded_modules.Remove(old_modules);
450     m_process->GetTarget().ModulesDidUnload(old_modules, false);
451   }
452 }
453 
454 ThreadPlanSP
455 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread,
456                                                      bool stop) {
457   ThreadPlanSP thread_plan_sp;
458 
459   StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
460   const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
461   Symbol *sym = context.symbol;
462 
463   if (sym == nullptr || !sym->IsTrampoline())
464     return thread_plan_sp;
465 
466   ConstString sym_name = sym->GetName();
467   if (!sym_name)
468     return thread_plan_sp;
469 
470   SymbolContextList target_symbols;
471   Target &target = thread.GetProcess()->GetTarget();
472   const ModuleList &images = target.GetImages();
473 
474   images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
475   size_t num_targets = target_symbols.GetSize();
476   if (!num_targets)
477     return thread_plan_sp;
478 
479   typedef std::vector<lldb::addr_t> AddressVector;
480   AddressVector addrs;
481   for (size_t i = 0; i < num_targets; ++i) {
482     SymbolContext context;
483     AddressRange range;
484     if (target_symbols.GetContextAtIndex(i, context)) {
485       context.GetAddressRange(eSymbolContextEverything, 0, false, range);
486       lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
487       if (addr != LLDB_INVALID_ADDRESS)
488         addrs.push_back(addr);
489     }
490   }
491 
492   if (addrs.size() > 0) {
493     AddressVector::iterator start = addrs.begin();
494     AddressVector::iterator end = addrs.end();
495 
496     llvm::sort(start, end);
497     addrs.erase(std::unique(start, end), end);
498     thread_plan_sp =
499         std::make_shared<ThreadPlanRunToAddress>(thread, addrs, stop);
500   }
501 
502   return thread_plan_sp;
503 }
504 
505 void DynamicLoaderPOSIXDYLD::LoadVDSO() {
506   if (m_vdso_base == LLDB_INVALID_ADDRESS)
507     return;
508 
509   FileSpec file("[vdso]");
510 
511   MemoryRegionInfo info;
512   Status status = m_process->GetMemoryRegionInfo(m_vdso_base, info);
513   if (status.Fail()) {
514     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
515     LLDB_LOG(log, "Failed to get vdso region info: {0}", status);
516     return;
517   }
518 
519   if (ModuleSP module_sp = m_process->ReadModuleFromMemory(
520           file, m_vdso_base, info.GetRange().GetByteSize())) {
521     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_vdso_base, false);
522     m_process->GetTarget().GetImages().AppendIfNeeded(module_sp);
523   }
524 }
525 
526 ModuleSP DynamicLoaderPOSIXDYLD::LoadInterpreterModule() {
527   if (m_interpreter_base == LLDB_INVALID_ADDRESS)
528     return nullptr;
529 
530   MemoryRegionInfo info;
531   Target &target = m_process->GetTarget();
532   Status status = m_process->GetMemoryRegionInfo(m_interpreter_base, info);
533   if (status.Fail() || info.GetMapped() != MemoryRegionInfo::eYes ||
534       info.GetName().IsEmpty()) {
535     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
536     LLDB_LOG(log, "Failed to get interpreter region info: {0}", status);
537     return nullptr;
538   }
539 
540   FileSpec file(info.GetName().GetCString());
541   ModuleSpec module_spec(file, target.GetArchitecture());
542 
543   if (ModuleSP module_sp = target.GetOrCreateModule(module_spec,
544                                                     true /* notify */)) {
545     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_interpreter_base,
546                          false);
547     return module_sp;
548   }
549   return nullptr;
550 }
551 
552 void DynamicLoaderPOSIXDYLD::LoadAllCurrentModules() {
553   DYLDRendezvous::iterator I;
554   DYLDRendezvous::iterator E;
555   ModuleList module_list;
556   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
557 
558   LoadVDSO();
559 
560   if (!m_rendezvous.Resolve()) {
561     LLDB_LOGF(log,
562               "DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD "
563               "rendezvous address",
564               __FUNCTION__);
565     return;
566   }
567 
568   // The rendezvous class doesn't enumerate the main module, so track that
569   // ourselves here.
570   ModuleSP executable = GetTargetExecutable();
571   m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
572 
573   std::vector<FileSpec> module_names;
574   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
575     module_names.push_back(I->file_spec);
576   m_process->PrefetchModuleSpecs(
577       module_names, m_process->GetTarget().GetArchitecture().GetTriple());
578 
579   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) {
580     ModuleSP module_sp =
581         LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
582     if (module_sp.get()) {
583       LLDB_LOG(log, "LoadAllCurrentModules loading module: {0}",
584                I->file_spec.GetFilename());
585       module_list.Append(module_sp);
586     } else {
587       Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
588       LLDB_LOGF(
589           log,
590           "DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
591           __FUNCTION__, I->file_spec.GetCString(), I->base_addr);
592     }
593   }
594 
595   m_process->GetTarget().ModulesDidLoad(module_list);
596 }
597 
598 addr_t DynamicLoaderPOSIXDYLD::ComputeLoadOffset() {
599   addr_t virt_entry;
600 
601   if (m_load_offset != LLDB_INVALID_ADDRESS)
602     return m_load_offset;
603 
604   if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
605     return LLDB_INVALID_ADDRESS;
606 
607   ModuleSP module = m_process->GetTarget().GetExecutableModule();
608   if (!module)
609     return LLDB_INVALID_ADDRESS;
610 
611   ObjectFile *exe = module->GetObjectFile();
612   if (!exe)
613     return LLDB_INVALID_ADDRESS;
614 
615   Address file_entry = exe->GetEntryPointAddress();
616 
617   if (!file_entry.IsValid())
618     return LLDB_INVALID_ADDRESS;
619 
620   m_load_offset = virt_entry - file_entry.GetFileAddress();
621   return m_load_offset;
622 }
623 
624 void DynamicLoaderPOSIXDYLD::EvalSpecialModulesStatus() {
625   if (llvm::Optional<uint64_t> vdso_base =
626           m_auxv->GetAuxValue(AuxVector::AUXV_AT_SYSINFO_EHDR))
627     m_vdso_base = *vdso_base;
628 
629   if (llvm::Optional<uint64_t> interpreter_base =
630           m_auxv->GetAuxValue(AuxVector::AUXV_AT_BASE))
631     m_interpreter_base = *interpreter_base;
632 }
633 
634 addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() {
635   if (m_entry_point != LLDB_INVALID_ADDRESS)
636     return m_entry_point;
637 
638   if (m_auxv == nullptr)
639     return LLDB_INVALID_ADDRESS;
640 
641   llvm::Optional<uint64_t> entry_point =
642       m_auxv->GetAuxValue(AuxVector::AUXV_AT_ENTRY);
643   if (!entry_point)
644     return LLDB_INVALID_ADDRESS;
645 
646   m_entry_point = static_cast<addr_t>(*entry_point);
647 
648   const ArchSpec &arch = m_process->GetTarget().GetArchitecture();
649 
650   // On ppc64, the entry point is actually a descriptor.  Dereference it.
651   if (arch.GetMachine() == llvm::Triple::ppc64)
652     m_entry_point = ReadUnsignedIntWithSizeInBytes(m_entry_point, 8);
653 
654   return m_entry_point;
655 }
656 
657 lldb::addr_t
658 DynamicLoaderPOSIXDYLD::GetThreadLocalData(const lldb::ModuleSP module_sp,
659                                            const lldb::ThreadSP thread,
660                                            lldb::addr_t tls_file_addr) {
661   auto it = m_loaded_modules.find(module_sp);
662   if (it == m_loaded_modules.end())
663     return LLDB_INVALID_ADDRESS;
664 
665   addr_t link_map = it->second;
666   if (link_map == LLDB_INVALID_ADDRESS)
667     return LLDB_INVALID_ADDRESS;
668 
669   const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
670   if (!metadata.valid)
671     return LLDB_INVALID_ADDRESS;
672 
673   // Get the thread pointer.
674   addr_t tp = thread->GetThreadPointer();
675   if (tp == LLDB_INVALID_ADDRESS)
676     return LLDB_INVALID_ADDRESS;
677 
678   // Find the module's modid.
679   int modid_size = 4; // FIXME(spucci): This isn't right for big-endian 64-bit
680   int64_t modid = ReadUnsignedIntWithSizeInBytes(
681       link_map + metadata.modid_offset, modid_size);
682   if (modid == -1)
683     return LLDB_INVALID_ADDRESS;
684 
685   // Lookup the DTV structure for this thread.
686   addr_t dtv_ptr = tp + metadata.dtv_offset;
687   addr_t dtv = ReadPointer(dtv_ptr);
688   if (dtv == LLDB_INVALID_ADDRESS)
689     return LLDB_INVALID_ADDRESS;
690 
691   // Find the TLS block for this module.
692   addr_t dtv_slot = dtv + metadata.dtv_slot_size * modid;
693   addr_t tls_block = ReadPointer(dtv_slot + metadata.tls_offset);
694 
695   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
696   LLDB_LOGF(log,
697             "DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
698             "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64
699             ", modid=%" PRId64 ", tls_block=0x%" PRIx64 "\n",
700             module_sp->GetObjectName().AsCString(""), link_map, tp,
701             (int64_t)modid, tls_block);
702 
703   if (tls_block == LLDB_INVALID_ADDRESS)
704     return LLDB_INVALID_ADDRESS;
705   else
706     return tls_block + tls_file_addr;
707 }
708 
709 void DynamicLoaderPOSIXDYLD::ResolveExecutableModule(
710     lldb::ModuleSP &module_sp) {
711   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
712 
713   if (m_process == nullptr)
714     return;
715 
716   auto &target = m_process->GetTarget();
717   const auto platform_sp = target.GetPlatform();
718 
719   ProcessInstanceInfo process_info;
720   if (!m_process->GetProcessInfo(process_info)) {
721     LLDB_LOGF(log,
722               "DynamicLoaderPOSIXDYLD::%s - failed to get process info for "
723               "pid %" PRIu64,
724               __FUNCTION__, m_process->GetID());
725     return;
726   }
727 
728   LLDB_LOGF(
729       log, "DynamicLoaderPOSIXDYLD::%s - got executable by pid %" PRIu64 ": %s",
730       __FUNCTION__, m_process->GetID(),
731       process_info.GetExecutableFile().GetPath().c_str());
732 
733   ModuleSpec module_spec(process_info.GetExecutableFile(),
734                          process_info.GetArchitecture());
735   if (module_sp && module_sp->MatchesModuleSpec(module_spec))
736     return;
737 
738   const auto executable_search_paths(Target::GetDefaultExecutableSearchPaths());
739   auto error = platform_sp->ResolveExecutable(
740       module_spec, module_sp,
741       !executable_search_paths.IsEmpty() ? &executable_search_paths : nullptr);
742   if (error.Fail()) {
743     StreamString stream;
744     module_spec.Dump(stream);
745 
746     LLDB_LOGF(log,
747               "DynamicLoaderPOSIXDYLD::%s - failed to resolve executable "
748               "with module spec \"%s\": %s",
749               __FUNCTION__, stream.GetData(), error.AsCString());
750     return;
751   }
752 
753   target.SetExecutableModule(module_sp, eLoadDependentsNo);
754 }
755 
756 bool DynamicLoaderPOSIXDYLD::AlwaysRelyOnEHUnwindInfo(
757     lldb_private::SymbolContext &sym_ctx) {
758   ModuleSP module_sp;
759   if (sym_ctx.symbol)
760     module_sp = sym_ctx.symbol->GetAddressRef().GetModule();
761   if (!module_sp && sym_ctx.function)
762     module_sp =
763         sym_ctx.function->GetAddressRange().GetBaseAddress().GetModule();
764   if (!module_sp)
765     return false;
766 
767   return module_sp->GetFileSpec().GetPath() == "[vdso]";
768 }
769