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         triple_ref.getOS() == llvm::Triple::OpenBSD)
67       create = true;
68   }
69 
70   if (create)
71     return new DynamicLoaderPOSIXDYLD(process);
72   return nullptr;
73 }
74 
75 DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process)
76     : DynamicLoader(process), m_rendezvous(process),
77       m_load_offset(LLDB_INVALID_ADDRESS), m_entry_point(LLDB_INVALID_ADDRESS),
78       m_auxv(), m_dyld_bid(LLDB_INVALID_BREAK_ID),
79       m_vdso_base(LLDB_INVALID_ADDRESS),
80       m_interpreter_base(LLDB_INVALID_ADDRESS), m_initial_modules_added(false) {
81 }
82 
83 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD() {
84   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
85     m_process->GetTarget().RemoveBreakpointByID(m_dyld_bid);
86     m_dyld_bid = LLDB_INVALID_BREAK_ID;
87   }
88 }
89 
90 void DynamicLoaderPOSIXDYLD::DidAttach() {
91   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
92   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64, __FUNCTION__,
93             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
94   m_auxv = std::make_unique<AuxVector>(m_process->GetAuxvData());
95 
96   LLDB_LOGF(
97       log, "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " reloaded auxv data",
98       __FUNCTION__, m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
99 
100   // ask the process if it can load any of its own modules
101   auto error = m_process->LoadModules();
102   LLDB_LOG_ERROR(log, std::move(error), "Couldn't load modules: {0}");
103 
104   ModuleSP executable_sp = GetTargetExecutable();
105   ResolveExecutableModule(executable_sp);
106   m_rendezvous.UpdateExecutablePath();
107 
108   // find the main process load offset
109   addr_t load_offset = ComputeLoadOffset();
110   LLDB_LOGF(log,
111             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
112             " executable '%s', load_offset 0x%" PRIx64,
113             __FUNCTION__,
114             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
115             executable_sp ? executable_sp->GetFileSpec().GetPath().c_str()
116                           : "<null executable>",
117             load_offset);
118 
119   EvalSpecialModulesStatus();
120 
121   // if we dont have a load address we cant re-base
122   bool rebase_exec = load_offset != LLDB_INVALID_ADDRESS;
123 
124   // if we have a valid executable
125   if (executable_sp.get()) {
126     lldb_private::ObjectFile *obj = executable_sp->GetObjectFile();
127     if (obj) {
128       // don't rebase if the module already has a load address
129       Target &target = m_process->GetTarget();
130       Address addr = obj->GetImageInfoAddress(&target);
131       if (addr.GetLoadAddress(&target) != LLDB_INVALID_ADDRESS)
132         rebase_exec = false;
133     }
134   } else {
135     // no executable, nothing to re-base
136     rebase_exec = false;
137   }
138 
139   // if the target executable should be re-based
140   if (rebase_exec) {
141     ModuleList module_list;
142 
143     module_list.Append(executable_sp);
144     LLDB_LOGF(log,
145               "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
146               " added executable '%s' to module load list",
147               __FUNCTION__,
148               m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
149               executable_sp->GetFileSpec().GetPath().c_str());
150 
151     UpdateLoadedSections(executable_sp, LLDB_INVALID_ADDRESS, load_offset,
152                          true);
153 
154     LoadAllCurrentModules();
155 
156     m_process->GetTarget().ModulesDidLoad(module_list);
157     if (log) {
158       LLDB_LOGF(log,
159                 "DynamicLoaderPOSIXDYLD::%s told the target about the "
160                 "modules that loaded:",
161                 __FUNCTION__);
162       for (auto module_sp : module_list.Modules()) {
163         LLDB_LOGF(log, "-- [module] %s (pid %" PRIu64 ")",
164                   module_sp ? module_sp->GetFileSpec().GetPath().c_str()
165                             : "<null>",
166                   m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
167       }
168     }
169   }
170 
171   if (executable_sp.get()) {
172     if (!SetRendezvousBreakpoint()) {
173       // If we cannot establish rendezvous breakpoint right now we'll try again
174       // at entry point.
175       ProbeEntry();
176     }
177   }
178 }
179 
180 void DynamicLoaderPOSIXDYLD::DidLaunch() {
181   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
182   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s()", __FUNCTION__);
183 
184   ModuleSP executable;
185   addr_t load_offset;
186 
187   m_auxv = std::make_unique<AuxVector>(m_process->GetAuxvData());
188 
189   executable = GetTargetExecutable();
190   load_offset = ComputeLoadOffset();
191   EvalSpecialModulesStatus();
192 
193   if (executable.get() && load_offset != LLDB_INVALID_ADDRESS) {
194     ModuleList module_list;
195     module_list.Append(executable);
196     UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset, true);
197 
198     LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s about to call ProbeEntry()",
199               __FUNCTION__);
200 
201     if (!SetRendezvousBreakpoint()) {
202       // If we cannot establish rendezvous breakpoint right now we'll try again
203       // at entry point.
204       ProbeEntry();
205     }
206 
207     LoadVDSO();
208     m_process->GetTarget().ModulesDidLoad(module_list);
209   }
210 }
211 
212 Status DynamicLoaderPOSIXDYLD::CanLoadImage() { return Status(); }
213 
214 void DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module,
215                                                   addr_t link_map_addr,
216                                                   addr_t base_addr,
217                                                   bool base_addr_is_offset) {
218   m_loaded_modules[module] = link_map_addr;
219   UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
220 }
221 
222 void DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module) {
223   m_loaded_modules.erase(module);
224 
225   UnloadSectionsCommon(module);
226 }
227 
228 void DynamicLoaderPOSIXDYLD::ProbeEntry() {
229   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
230 
231   const addr_t entry = GetEntryPoint();
232   if (entry == LLDB_INVALID_ADDRESS) {
233     LLDB_LOGF(
234         log,
235         "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
236         " GetEntryPoint() returned no address, not setting entry breakpoint",
237         __FUNCTION__, m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
238     return;
239   }
240 
241   LLDB_LOGF(log,
242             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
243             " GetEntryPoint() returned address 0x%" PRIx64
244             ", setting entry breakpoint",
245             __FUNCTION__,
246             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID, entry);
247 
248   if (m_process) {
249     Breakpoint *const entry_break =
250         m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
251     entry_break->SetCallback(EntryBreakpointHit, this, true);
252     entry_break->SetBreakpointKind("shared-library-event");
253 
254     // Shoudn't hit this more than once.
255     entry_break->SetOneShot(true);
256   }
257 }
258 
259 // The runtime linker has run and initialized the rendezvous structure once the
260 // process has hit its entry point.  When we hit the corresponding breakpoint
261 // we interrogate the rendezvous structure to get the load addresses of all
262 // dependent modules for the process.  Similarly, we can discover the runtime
263 // linker function and setup a breakpoint to notify us of any dynamically
264 // loaded modules (via dlopen).
265 bool DynamicLoaderPOSIXDYLD::EntryBreakpointHit(
266     void *baton, StoppointCallbackContext *context, user_id_t break_id,
267     user_id_t break_loc_id) {
268   assert(baton && "null baton");
269   if (!baton)
270     return false;
271 
272   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
273   DynamicLoaderPOSIXDYLD *const dyld_instance =
274       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
275   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
276             __FUNCTION__,
277             dyld_instance->m_process ? dyld_instance->m_process->GetID()
278                                      : LLDB_INVALID_PROCESS_ID);
279 
280   // Disable the breakpoint --- if a stop happens right after this, which we've
281   // seen on occasion, we don't want the breakpoint stepping thread-plan logic
282   // to show a breakpoint instruction at the disassembled entry point to the
283   // program.  Disabling it prevents it.  (One-shot is not enough - one-shot
284   // removal logic only happens after the breakpoint goes public, which wasn't
285   // happening in our scenario).
286   if (dyld_instance->m_process) {
287     BreakpointSP breakpoint_sp =
288         dyld_instance->m_process->GetTarget().GetBreakpointByID(break_id);
289     if (breakpoint_sp) {
290       LLDB_LOGF(log,
291                 "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
292                 " disabling breakpoint id %" PRIu64,
293                 __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
294       breakpoint_sp->SetEnabled(false);
295     } else {
296       LLDB_LOGF(log,
297                 "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
298                 " failed to find breakpoint for breakpoint id %" PRIu64,
299                 __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
300     }
301   } else {
302     LLDB_LOGF(log,
303               "DynamicLoaderPOSIXDYLD::%s breakpoint id %" PRIu64
304               " no Process instance!  Cannot disable breakpoint",
305               __FUNCTION__, break_id);
306   }
307 
308   dyld_instance->LoadAllCurrentModules();
309   dyld_instance->SetRendezvousBreakpoint();
310   return false; // Continue running.
311 }
312 
313 bool DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() {
314   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
315   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
316     LLDB_LOG(log,
317              "Rendezvous breakpoint breakpoint id {0} for pid {1}"
318              "is already set.",
319              m_dyld_bid,
320              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
321     return true;
322   }
323 
324   addr_t break_addr;
325   Target &target = m_process->GetTarget();
326   BreakpointSP dyld_break;
327   if (m_rendezvous.IsValid()) {
328     break_addr = m_rendezvous.GetBreakAddress();
329     LLDB_LOG(log, "Setting rendezvous break address for pid {0} at {1:x}",
330              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
331              break_addr);
332     dyld_break = target.CreateBreakpoint(break_addr, true, false);
333   } else {
334     LLDB_LOG(log, "Rendezvous structure is not set up yet. "
335                   "Trying to locate rendezvous breakpoint in the interpreter "
336                   "by symbol name.");
337     ModuleSP interpreter = LoadInterpreterModule();
338     if (!interpreter) {
339       LLDB_LOG(log, "Can't find interpreter, rendezvous breakpoint isn't set.");
340       return false;
341     }
342 
343     // Function names from different dynamic loaders that are known to be used
344     // as rendezvous between the loader and debuggers.
345     static std::vector<std::string> DebugStateCandidates{
346         "_dl_debug_state", "rtld_db_dlactivity", "__dl_rtld_db_dlactivity",
347         "r_debug_state",   "_r_debug_state",     "_rtld_debug_state",
348     };
349 
350     FileSpecList containingModules;
351     containingModules.Append(interpreter->GetFileSpec());
352     dyld_break = target.CreateBreakpoint(
353         &containingModules, nullptr /* containingSourceFiles */,
354         DebugStateCandidates, eFunctionNameTypeFull, eLanguageTypeC,
355         0,           /* offset */
356         eLazyBoolNo, /* skip_prologue */
357         true,        /* internal */
358         false /* request_hardware */);
359   }
360 
361   if (dyld_break->GetNumResolvedLocations() != 1) {
362     LLDB_LOG(
363         log,
364         "Rendezvous breakpoint has abnormal number of"
365         " resolved locations ({0}) in pid {1}. It's supposed to be exactly 1.",
366         dyld_break->GetNumResolvedLocations(),
367         m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
368 
369     target.RemoveBreakpointByID(dyld_break->GetID());
370     return false;
371   }
372 
373   BreakpointLocationSP location = dyld_break->GetLocationAtIndex(0);
374   LLDB_LOG(log,
375            "Successfully set rendezvous breakpoint at address {0:x} "
376            "for pid {1}",
377            location->GetLoadAddress(),
378            m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
379 
380   dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
381   dyld_break->SetBreakpointKind("shared-library-event");
382   m_dyld_bid = dyld_break->GetID();
383   return true;
384 }
385 
386 bool DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(
387     void *baton, StoppointCallbackContext *context, user_id_t break_id,
388     user_id_t break_loc_id) {
389   assert(baton && "null baton");
390   if (!baton)
391     return false;
392 
393   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
394   DynamicLoaderPOSIXDYLD *const dyld_instance =
395       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
396   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
397             __FUNCTION__,
398             dyld_instance->m_process ? dyld_instance->m_process->GetID()
399                                      : LLDB_INVALID_PROCESS_ID);
400 
401   dyld_instance->RefreshModules();
402 
403   // Return true to stop the target, false to just let the target run.
404   const bool stop_when_images_change = dyld_instance->GetStopWhenImagesChange();
405   LLDB_LOGF(log,
406             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
407             " stop_when_images_change=%s",
408             __FUNCTION__,
409             dyld_instance->m_process ? dyld_instance->m_process->GetID()
410                                      : LLDB_INVALID_PROCESS_ID,
411             stop_when_images_change ? "true" : "false");
412   return stop_when_images_change;
413 }
414 
415 void DynamicLoaderPOSIXDYLD::RefreshModules() {
416   if (!m_rendezvous.Resolve())
417     return;
418 
419   DYLDRendezvous::iterator I;
420   DYLDRendezvous::iterator E;
421 
422   ModuleList &loaded_modules = m_process->GetTarget().GetImages();
423 
424   if (m_rendezvous.ModulesDidLoad() || !m_initial_modules_added) {
425     ModuleList new_modules;
426 
427     // If this is the first time rendezvous breakpoint fires, we need
428     // to take care of adding all the initial modules reported by
429     // the loader.  This is necessary to list ld-linux.so on Linux,
430     // and all DT_NEEDED entries on *BSD.
431     if (m_initial_modules_added) {
432       I = m_rendezvous.loaded_begin();
433       E = m_rendezvous.loaded_end();
434     } else {
435       I = m_rendezvous.begin();
436       E = m_rendezvous.end();
437       m_initial_modules_added = true;
438     }
439     for (; I != E; ++I) {
440       ModuleSP module_sp =
441           LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
442       if (module_sp.get()) {
443         if (module_sp->GetObjectFile()->GetBaseAddress().GetLoadAddress(
444                 &m_process->GetTarget()) == m_interpreter_base &&
445             module_sp != m_interpreter_module.lock()) {
446           // If this is a duplicate instance of ld.so, unload it.  We may end up
447           // with it if we load it via a different path than before (symlink
448           // vs real path).
449           // TODO: remove this once we either fix library matching or avoid
450           // loading the interpreter when setting the rendezvous breakpoint.
451           UnloadSections(module_sp);
452           loaded_modules.Remove(module_sp);
453           continue;
454         }
455 
456         loaded_modules.AppendIfNeeded(module_sp);
457         new_modules.Append(module_sp);
458       }
459     }
460     m_process->GetTarget().ModulesDidLoad(new_modules);
461   }
462 
463   if (m_rendezvous.ModulesDidUnload()) {
464     ModuleList old_modules;
465 
466     E = m_rendezvous.unloaded_end();
467     for (I = m_rendezvous.unloaded_begin(); I != E; ++I) {
468       ModuleSpec module_spec{I->file_spec};
469       ModuleSP module_sp = loaded_modules.FindFirstModule(module_spec);
470 
471       if (module_sp.get()) {
472         old_modules.Append(module_sp);
473         UnloadSections(module_sp);
474       }
475     }
476     loaded_modules.Remove(old_modules);
477     m_process->GetTarget().ModulesDidUnload(old_modules, false);
478   }
479 }
480 
481 ThreadPlanSP
482 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread,
483                                                      bool stop) {
484   ThreadPlanSP thread_plan_sp;
485 
486   StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
487   const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
488   Symbol *sym = context.symbol;
489 
490   if (sym == nullptr || !sym->IsTrampoline())
491     return thread_plan_sp;
492 
493   ConstString sym_name = sym->GetName();
494   if (!sym_name)
495     return thread_plan_sp;
496 
497   SymbolContextList target_symbols;
498   Target &target = thread.GetProcess()->GetTarget();
499   const ModuleList &images = target.GetImages();
500 
501   images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
502   size_t num_targets = target_symbols.GetSize();
503   if (!num_targets)
504     return thread_plan_sp;
505 
506   typedef std::vector<lldb::addr_t> AddressVector;
507   AddressVector addrs;
508   for (size_t i = 0; i < num_targets; ++i) {
509     SymbolContext context;
510     AddressRange range;
511     if (target_symbols.GetContextAtIndex(i, context)) {
512       context.GetAddressRange(eSymbolContextEverything, 0, false, range);
513       lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
514       if (addr != LLDB_INVALID_ADDRESS)
515         addrs.push_back(addr);
516     }
517   }
518 
519   if (addrs.size() > 0) {
520     AddressVector::iterator start = addrs.begin();
521     AddressVector::iterator end = addrs.end();
522 
523     llvm::sort(start, end);
524     addrs.erase(std::unique(start, end), end);
525     thread_plan_sp =
526         std::make_shared<ThreadPlanRunToAddress>(thread, addrs, stop);
527   }
528 
529   return thread_plan_sp;
530 }
531 
532 void DynamicLoaderPOSIXDYLD::LoadVDSO() {
533   if (m_vdso_base == LLDB_INVALID_ADDRESS)
534     return;
535 
536   FileSpec file("[vdso]");
537 
538   MemoryRegionInfo info;
539   Status status = m_process->GetMemoryRegionInfo(m_vdso_base, info);
540   if (status.Fail()) {
541     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
542     LLDB_LOG(log, "Failed to get vdso region info: {0}", status);
543     return;
544   }
545 
546   if (ModuleSP module_sp = m_process->ReadModuleFromMemory(
547           file, m_vdso_base, info.GetRange().GetByteSize())) {
548     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_vdso_base, false);
549     m_process->GetTarget().GetImages().AppendIfNeeded(module_sp);
550   }
551 }
552 
553 ModuleSP DynamicLoaderPOSIXDYLD::LoadInterpreterModule() {
554   if (m_interpreter_base == LLDB_INVALID_ADDRESS)
555     return nullptr;
556 
557   MemoryRegionInfo info;
558   Target &target = m_process->GetTarget();
559   Status status = m_process->GetMemoryRegionInfo(m_interpreter_base, info);
560   if (status.Fail() || info.GetMapped() != MemoryRegionInfo::eYes ||
561       info.GetName().IsEmpty()) {
562     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
563     LLDB_LOG(log, "Failed to get interpreter region info: {0}", status);
564     return nullptr;
565   }
566 
567   FileSpec file(info.GetName().GetCString());
568   ModuleSpec module_spec(file, target.GetArchitecture());
569 
570   if (ModuleSP module_sp = target.GetOrCreateModule(module_spec,
571                                                     true /* notify */)) {
572     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_interpreter_base,
573                          false);
574     m_interpreter_module = module_sp;
575     return module_sp;
576   }
577   return nullptr;
578 }
579 
580 void DynamicLoaderPOSIXDYLD::LoadAllCurrentModules() {
581   DYLDRendezvous::iterator I;
582   DYLDRendezvous::iterator E;
583   ModuleList module_list;
584   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
585 
586   LoadVDSO();
587 
588   if (!m_rendezvous.Resolve()) {
589     LLDB_LOGF(log,
590               "DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD "
591               "rendezvous address",
592               __FUNCTION__);
593     return;
594   }
595 
596   // The rendezvous class doesn't enumerate the main module, so track that
597   // ourselves here.
598   ModuleSP executable = GetTargetExecutable();
599   m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
600 
601   std::vector<FileSpec> module_names;
602   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
603     module_names.push_back(I->file_spec);
604   m_process->PrefetchModuleSpecs(
605       module_names, m_process->GetTarget().GetArchitecture().GetTriple());
606 
607   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) {
608     ModuleSP module_sp =
609         LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
610     if (module_sp.get()) {
611       LLDB_LOG(log, "LoadAllCurrentModules loading module: {0}",
612                I->file_spec.GetFilename());
613       module_list.Append(module_sp);
614     } else {
615       Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
616       LLDB_LOGF(
617           log,
618           "DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
619           __FUNCTION__, I->file_spec.GetCString(), I->base_addr);
620     }
621   }
622 
623   m_process->GetTarget().ModulesDidLoad(module_list);
624 }
625 
626 addr_t DynamicLoaderPOSIXDYLD::ComputeLoadOffset() {
627   addr_t virt_entry;
628 
629   if (m_load_offset != LLDB_INVALID_ADDRESS)
630     return m_load_offset;
631 
632   if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
633     return LLDB_INVALID_ADDRESS;
634 
635   ModuleSP module = m_process->GetTarget().GetExecutableModule();
636   if (!module)
637     return LLDB_INVALID_ADDRESS;
638 
639   ObjectFile *exe = module->GetObjectFile();
640   if (!exe)
641     return LLDB_INVALID_ADDRESS;
642 
643   Address file_entry = exe->GetEntryPointAddress();
644 
645   if (!file_entry.IsValid())
646     return LLDB_INVALID_ADDRESS;
647 
648   m_load_offset = virt_entry - file_entry.GetFileAddress();
649   return m_load_offset;
650 }
651 
652 void DynamicLoaderPOSIXDYLD::EvalSpecialModulesStatus() {
653   if (llvm::Optional<uint64_t> vdso_base =
654           m_auxv->GetAuxValue(AuxVector::AUXV_AT_SYSINFO_EHDR))
655     m_vdso_base = *vdso_base;
656 
657   if (llvm::Optional<uint64_t> interpreter_base =
658           m_auxv->GetAuxValue(AuxVector::AUXV_AT_BASE))
659     m_interpreter_base = *interpreter_base;
660 }
661 
662 addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() {
663   if (m_entry_point != LLDB_INVALID_ADDRESS)
664     return m_entry_point;
665 
666   if (m_auxv == nullptr)
667     return LLDB_INVALID_ADDRESS;
668 
669   llvm::Optional<uint64_t> entry_point =
670       m_auxv->GetAuxValue(AuxVector::AUXV_AT_ENTRY);
671   if (!entry_point)
672     return LLDB_INVALID_ADDRESS;
673 
674   m_entry_point = static_cast<addr_t>(*entry_point);
675 
676   const ArchSpec &arch = m_process->GetTarget().GetArchitecture();
677 
678   // On ppc64, the entry point is actually a descriptor.  Dereference it.
679   if (arch.GetMachine() == llvm::Triple::ppc64)
680     m_entry_point = ReadUnsignedIntWithSizeInBytes(m_entry_point, 8);
681 
682   return m_entry_point;
683 }
684 
685 lldb::addr_t
686 DynamicLoaderPOSIXDYLD::GetThreadLocalData(const lldb::ModuleSP module_sp,
687                                            const lldb::ThreadSP thread,
688                                            lldb::addr_t tls_file_addr) {
689   auto it = m_loaded_modules.find(module_sp);
690   if (it == m_loaded_modules.end())
691     return LLDB_INVALID_ADDRESS;
692 
693   addr_t link_map = it->second;
694   if (link_map == LLDB_INVALID_ADDRESS)
695     return LLDB_INVALID_ADDRESS;
696 
697   const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
698   if (!metadata.valid)
699     return LLDB_INVALID_ADDRESS;
700 
701   // Get the thread pointer.
702   addr_t tp = thread->GetThreadPointer();
703   if (tp == LLDB_INVALID_ADDRESS)
704     return LLDB_INVALID_ADDRESS;
705 
706   // Find the module's modid.
707   int modid_size = 4; // FIXME(spucci): This isn't right for big-endian 64-bit
708   int64_t modid = ReadUnsignedIntWithSizeInBytes(
709       link_map + metadata.modid_offset, modid_size);
710   if (modid == -1)
711     return LLDB_INVALID_ADDRESS;
712 
713   // Lookup the DTV structure for this thread.
714   addr_t dtv_ptr = tp + metadata.dtv_offset;
715   addr_t dtv = ReadPointer(dtv_ptr);
716   if (dtv == LLDB_INVALID_ADDRESS)
717     return LLDB_INVALID_ADDRESS;
718 
719   // Find the TLS block for this module.
720   addr_t dtv_slot = dtv + metadata.dtv_slot_size * modid;
721   addr_t tls_block = ReadPointer(dtv_slot + metadata.tls_offset);
722 
723   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
724   LLDB_LOGF(log,
725             "DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
726             "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64
727             ", modid=%" PRId64 ", tls_block=0x%" PRIx64 "\n",
728             module_sp->GetObjectName().AsCString(""), link_map, tp,
729             (int64_t)modid, tls_block);
730 
731   if (tls_block == LLDB_INVALID_ADDRESS)
732     return LLDB_INVALID_ADDRESS;
733   else
734     return tls_block + tls_file_addr;
735 }
736 
737 void DynamicLoaderPOSIXDYLD::ResolveExecutableModule(
738     lldb::ModuleSP &module_sp) {
739   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
740 
741   if (m_process == nullptr)
742     return;
743 
744   auto &target = m_process->GetTarget();
745   const auto platform_sp = target.GetPlatform();
746 
747   ProcessInstanceInfo process_info;
748   if (!m_process->GetProcessInfo(process_info)) {
749     LLDB_LOGF(log,
750               "DynamicLoaderPOSIXDYLD::%s - failed to get process info for "
751               "pid %" PRIu64,
752               __FUNCTION__, m_process->GetID());
753     return;
754   }
755 
756   LLDB_LOGF(
757       log, "DynamicLoaderPOSIXDYLD::%s - got executable by pid %" PRIu64 ": %s",
758       __FUNCTION__, m_process->GetID(),
759       process_info.GetExecutableFile().GetPath().c_str());
760 
761   ModuleSpec module_spec(process_info.GetExecutableFile(),
762                          process_info.GetArchitecture());
763   if (module_sp && module_sp->MatchesModuleSpec(module_spec))
764     return;
765 
766   const auto executable_search_paths(Target::GetDefaultExecutableSearchPaths());
767   auto error = platform_sp->ResolveExecutable(
768       module_spec, module_sp,
769       !executable_search_paths.IsEmpty() ? &executable_search_paths : nullptr);
770   if (error.Fail()) {
771     StreamString stream;
772     module_spec.Dump(stream);
773 
774     LLDB_LOGF(log,
775               "DynamicLoaderPOSIXDYLD::%s - failed to resolve executable "
776               "with module spec \"%s\": %s",
777               __FUNCTION__, stream.GetData(), error.AsCString());
778     return;
779   }
780 
781   target.SetExecutableModule(module_sp, eLoadDependentsNo);
782 }
783 
784 bool DynamicLoaderPOSIXDYLD::AlwaysRelyOnEHUnwindInfo(
785     lldb_private::SymbolContext &sym_ctx) {
786   ModuleSP module_sp;
787   if (sym_ctx.symbol)
788     module_sp = sym_ctx.symbol->GetAddressRef().GetModule();
789   if (!module_sp && sym_ctx.function)
790     module_sp =
791         sym_ctx.function->GetAddressRange().GetBaseAddress().GetModule();
792   if (!module_sp)
793     return false;
794 
795   return module_sp->GetFileSpec().GetPath() == "[vdso]";
796 }
797