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 
LLDB_PLUGIN_DEFINE_ADV(DynamicLoaderPOSIXDYLD,DynamicLoaderPosixDYLD)32 LLDB_PLUGIN_DEFINE_ADV(DynamicLoaderPOSIXDYLD, DynamicLoaderPosixDYLD)
33 
34 void DynamicLoaderPOSIXDYLD::Initialize() {
35   PluginManager::RegisterPlugin(GetPluginNameStatic(),
36                                 GetPluginDescriptionStatic(), CreateInstance);
37 }
38 
Terminate()39 void DynamicLoaderPOSIXDYLD::Terminate() {}
40 
GetPluginName()41 lldb_private::ConstString DynamicLoaderPOSIXDYLD::GetPluginName() {
42   return GetPluginNameStatic();
43 }
44 
GetPluginNameStatic()45 lldb_private::ConstString DynamicLoaderPOSIXDYLD::GetPluginNameStatic() {
46   static ConstString g_name("linux-dyld");
47   return g_name;
48 }
49 
GetPluginDescriptionStatic()50 const char *DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic() {
51   return "Dynamic loader plug-in that watches for shared library "
52          "loads/unloads in POSIX processes.";
53 }
54 
GetPluginVersion()55 uint32_t DynamicLoaderPOSIXDYLD::GetPluginVersion() { return 1; }
56 
CreateInstance(Process * process,bool force)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 
DynamicLoaderPOSIXDYLD(Process * process)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), m_initial_modules_added(false) {
80 }
81 
~DynamicLoaderPOSIXDYLD()82 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD() {
83   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
84     m_process->GetTarget().RemoveBreakpointByID(m_dyld_bid);
85     m_dyld_bid = LLDB_INVALID_BREAK_ID;
86   }
87 }
88 
DidAttach()89 void DynamicLoaderPOSIXDYLD::DidAttach() {
90   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
91   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64, __FUNCTION__,
92             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
93   m_auxv = std::make_unique<AuxVector>(m_process->GetAuxvData());
94 
95   LLDB_LOGF(
96       log, "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " reloaded auxv data",
97       __FUNCTION__, m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
98 
99   // ask the process if it can load any of its own modules
100   auto error = m_process->LoadModules();
101   LLDB_LOG_ERROR(log, std::move(error), "Couldn't load modules: {0}");
102 
103   ModuleSP executable_sp = GetTargetExecutable();
104   ResolveExecutableModule(executable_sp);
105   m_rendezvous.UpdateExecutablePath();
106 
107   // find the main process load offset
108   addr_t load_offset = ComputeLoadOffset();
109   LLDB_LOGF(log,
110             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
111             " executable '%s', load_offset 0x%" PRIx64,
112             __FUNCTION__,
113             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
114             executable_sp ? executable_sp->GetFileSpec().GetPath().c_str()
115                           : "<null executable>",
116             load_offset);
117 
118   EvalSpecialModulesStatus();
119 
120   // if we dont have a load address we cant re-base
121   bool rebase_exec = load_offset != LLDB_INVALID_ADDRESS;
122 
123   // if we have a valid executable
124   if (executable_sp.get()) {
125     lldb_private::ObjectFile *obj = executable_sp->GetObjectFile();
126     if (obj) {
127       // don't rebase if the module already has a load address
128       Target &target = m_process->GetTarget();
129       Address addr = obj->GetImageInfoAddress(&target);
130       if (addr.GetLoadAddress(&target) != LLDB_INVALID_ADDRESS)
131         rebase_exec = false;
132     }
133   } else {
134     // no executable, nothing to re-base
135     rebase_exec = false;
136   }
137 
138   // if the target executable should be re-based
139   if (rebase_exec) {
140     ModuleList module_list;
141 
142     module_list.Append(executable_sp);
143     LLDB_LOGF(log,
144               "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
145               " added executable '%s' to module load list",
146               __FUNCTION__,
147               m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
148               executable_sp->GetFileSpec().GetPath().c_str());
149 
150     UpdateLoadedSections(executable_sp, LLDB_INVALID_ADDRESS, load_offset,
151                          true);
152 
153     LoadAllCurrentModules();
154 
155     m_process->GetTarget().ModulesDidLoad(module_list);
156     if (log) {
157       LLDB_LOGF(log,
158                 "DynamicLoaderPOSIXDYLD::%s told the target about the "
159                 "modules that loaded:",
160                 __FUNCTION__);
161       for (auto module_sp : module_list.Modules()) {
162         LLDB_LOGF(log, "-- [module] %s (pid %" PRIu64 ")",
163                   module_sp ? module_sp->GetFileSpec().GetPath().c_str()
164                             : "<null>",
165                   m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
166       }
167     }
168   }
169 
170   if (executable_sp.get()) {
171     if (!SetRendezvousBreakpoint()) {
172       // If we cannot establish rendezvous breakpoint right now we'll try again
173       // at entry point.
174       ProbeEntry();
175     }
176   }
177 }
178 
DidLaunch()179 void DynamicLoaderPOSIXDYLD::DidLaunch() {
180   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
181   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s()", __FUNCTION__);
182 
183   ModuleSP executable;
184   addr_t load_offset;
185 
186   m_auxv = std::make_unique<AuxVector>(m_process->GetAuxvData());
187 
188   executable = GetTargetExecutable();
189   load_offset = ComputeLoadOffset();
190   EvalSpecialModulesStatus();
191 
192   if (executable.get() && load_offset != LLDB_INVALID_ADDRESS) {
193     ModuleList module_list;
194     module_list.Append(executable);
195     UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset, true);
196 
197     LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s about to call ProbeEntry()",
198               __FUNCTION__);
199 
200     if (!SetRendezvousBreakpoint()) {
201       // If we cannot establish rendezvous breakpoint right now we'll try again
202       // at entry point.
203       ProbeEntry();
204     }
205 
206     LoadVDSO();
207     m_process->GetTarget().ModulesDidLoad(module_list);
208   }
209 }
210 
CanLoadImage()211 Status DynamicLoaderPOSIXDYLD::CanLoadImage() { return Status(); }
212 
UpdateLoadedSections(ModuleSP module,addr_t link_map_addr,addr_t base_addr,bool base_addr_is_offset)213 void DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module,
214                                                   addr_t link_map_addr,
215                                                   addr_t base_addr,
216                                                   bool base_addr_is_offset) {
217   m_loaded_modules[module] = link_map_addr;
218   UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
219 }
220 
UnloadSections(const ModuleSP module)221 void DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module) {
222   m_loaded_modules.erase(module);
223 
224   UnloadSectionsCommon(module);
225 }
226 
ProbeEntry()227 void DynamicLoaderPOSIXDYLD::ProbeEntry() {
228   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
229 
230   const addr_t entry = GetEntryPoint();
231   if (entry == LLDB_INVALID_ADDRESS) {
232     LLDB_LOGF(
233         log,
234         "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
235         " GetEntryPoint() returned no address, not setting entry breakpoint",
236         __FUNCTION__, m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
237     return;
238   }
239 
240   LLDB_LOGF(log,
241             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
242             " GetEntryPoint() returned address 0x%" PRIx64
243             ", setting entry breakpoint",
244             __FUNCTION__,
245             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID, entry);
246 
247   if (m_process) {
248     Breakpoint *const entry_break =
249         m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
250     entry_break->SetCallback(EntryBreakpointHit, this, true);
251     entry_break->SetBreakpointKind("shared-library-event");
252 
253     // Shoudn't hit this more than once.
254     entry_break->SetOneShot(true);
255   }
256 }
257 
258 // The runtime linker has run and initialized the rendezvous structure once the
259 // process has hit its entry point.  When we hit the corresponding breakpoint
260 // we interrogate the rendezvous structure to get the load addresses of all
261 // dependent modules for the process.  Similarly, we can discover the runtime
262 // linker function and setup a breakpoint to notify us of any dynamically
263 // loaded modules (via dlopen).
EntryBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)264 bool DynamicLoaderPOSIXDYLD::EntryBreakpointHit(
265     void *baton, StoppointCallbackContext *context, user_id_t break_id,
266     user_id_t break_loc_id) {
267   assert(baton && "null baton");
268   if (!baton)
269     return false;
270 
271   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
272   DynamicLoaderPOSIXDYLD *const dyld_instance =
273       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
274   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
275             __FUNCTION__,
276             dyld_instance->m_process ? dyld_instance->m_process->GetID()
277                                      : LLDB_INVALID_PROCESS_ID);
278 
279   // Disable the breakpoint --- if a stop happens right after this, which we've
280   // seen on occasion, we don't want the breakpoint stepping thread-plan logic
281   // to show a breakpoint instruction at the disassembled entry point to the
282   // program.  Disabling it prevents it.  (One-shot is not enough - one-shot
283   // removal logic only happens after the breakpoint goes public, which wasn't
284   // happening in our scenario).
285   if (dyld_instance->m_process) {
286     BreakpointSP breakpoint_sp =
287         dyld_instance->m_process->GetTarget().GetBreakpointByID(break_id);
288     if (breakpoint_sp) {
289       LLDB_LOGF(log,
290                 "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
291                 " disabling breakpoint id %" PRIu64,
292                 __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
293       breakpoint_sp->SetEnabled(false);
294     } else {
295       LLDB_LOGF(log,
296                 "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
297                 " failed to find breakpoint for breakpoint id %" PRIu64,
298                 __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
299     }
300   } else {
301     LLDB_LOGF(log,
302               "DynamicLoaderPOSIXDYLD::%s breakpoint id %" PRIu64
303               " no Process instance!  Cannot disable breakpoint",
304               __FUNCTION__, break_id);
305   }
306 
307   dyld_instance->LoadAllCurrentModules();
308   dyld_instance->SetRendezvousBreakpoint();
309   return false; // Continue running.
310 }
311 
SetRendezvousBreakpoint()312 bool DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() {
313   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
314   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
315     LLDB_LOG(log,
316              "Rendezvous breakpoint breakpoint id {0} for pid {1}"
317              "is already set.",
318              m_dyld_bid,
319              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
320     return true;
321   }
322 
323   addr_t break_addr;
324   Target &target = m_process->GetTarget();
325   BreakpointSP dyld_break;
326   if (m_rendezvous.IsValid()) {
327     break_addr = m_rendezvous.GetBreakAddress();
328     LLDB_LOG(log, "Setting rendezvous break address for pid {0} at {1:x}",
329              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
330              break_addr);
331     dyld_break = target.CreateBreakpoint(break_addr, true, false);
332   } else {
333     LLDB_LOG(log, "Rendezvous structure is not set up yet. "
334                   "Trying to locate rendezvous breakpoint in the interpreter "
335                   "by symbol name.");
336     ModuleSP interpreter = LoadInterpreterModule();
337     if (!interpreter) {
338       LLDB_LOG(log, "Can't find interpreter, rendezvous breakpoint isn't set.");
339       return false;
340     }
341 
342     // Function names from different dynamic loaders that are known to be used
343     // as rendezvous between the loader and debuggers.
344     static std::vector<std::string> DebugStateCandidates{
345         "_dl_debug_state", "rtld_db_dlactivity", "__dl_rtld_db_dlactivity",
346         "r_debug_state",   "_r_debug_state",     "_rtld_debug_state",
347     };
348 
349     FileSpecList containingModules;
350     containingModules.Append(interpreter->GetFileSpec());
351     dyld_break = target.CreateBreakpoint(
352         &containingModules, nullptr /* containingSourceFiles */,
353         DebugStateCandidates, eFunctionNameTypeFull, eLanguageTypeC,
354         0,           /* offset */
355         eLazyBoolNo, /* skip_prologue */
356         true,        /* internal */
357         false /* request_hardware */);
358   }
359 
360   if (dyld_break->GetNumResolvedLocations() != 1) {
361     LLDB_LOG(
362         log,
363         "Rendezvous breakpoint has abnormal number of"
364         " resolved locations ({0}) in pid {1}. It's supposed to be exactly 1.",
365         dyld_break->GetNumResolvedLocations(),
366         m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
367 
368     target.RemoveBreakpointByID(dyld_break->GetID());
369     return false;
370   }
371 
372   BreakpointLocationSP location = dyld_break->GetLocationAtIndex(0);
373   LLDB_LOG(log,
374            "Successfully set rendezvous breakpoint at address {0:x} "
375            "for pid {1}",
376            location->GetLoadAddress(),
377            m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
378 
379   dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
380   dyld_break->SetBreakpointKind("shared-library-event");
381   m_dyld_bid = dyld_break->GetID();
382   return true;
383 }
384 
RendezvousBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)385 bool DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(
386     void *baton, StoppointCallbackContext *context, user_id_t break_id,
387     user_id_t break_loc_id) {
388   assert(baton && "null baton");
389   if (!baton)
390     return false;
391 
392   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
393   DynamicLoaderPOSIXDYLD *const dyld_instance =
394       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
395   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
396             __FUNCTION__,
397             dyld_instance->m_process ? dyld_instance->m_process->GetID()
398                                      : LLDB_INVALID_PROCESS_ID);
399 
400   dyld_instance->RefreshModules();
401 
402   // Return true to stop the target, false to just let the target run.
403   const bool stop_when_images_change = dyld_instance->GetStopWhenImagesChange();
404   LLDB_LOGF(log,
405             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
406             " stop_when_images_change=%s",
407             __FUNCTION__,
408             dyld_instance->m_process ? dyld_instance->m_process->GetID()
409                                      : LLDB_INVALID_PROCESS_ID,
410             stop_when_images_change ? "true" : "false");
411   return stop_when_images_change;
412 }
413 
RefreshModules()414 void DynamicLoaderPOSIXDYLD::RefreshModules() {
415   if (!m_rendezvous.Resolve())
416     return;
417 
418   DYLDRendezvous::iterator I;
419   DYLDRendezvous::iterator E;
420 
421   ModuleList &loaded_modules = m_process->GetTarget().GetImages();
422 
423   if (m_rendezvous.ModulesDidLoad() || !m_initial_modules_added) {
424     ModuleList new_modules;
425 
426     // If this is the first time rendezvous breakpoint fires, we need
427     // to take care of adding all the initial modules reported by
428     // the loader.  This is necessary to list ld-linux.so on Linux,
429     // and all DT_NEEDED entries on *BSD.
430     if (m_initial_modules_added) {
431       I = m_rendezvous.loaded_begin();
432       E = m_rendezvous.loaded_end();
433     } else {
434       I = m_rendezvous.begin();
435       E = m_rendezvous.end();
436       m_initial_modules_added = true;
437     }
438     for (; I != E; ++I) {
439       ModuleSP module_sp =
440           LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
441       if (module_sp.get()) {
442         if (module_sp->GetObjectFile()->GetBaseAddress().GetLoadAddress(
443                 &m_process->GetTarget()) == m_interpreter_base &&
444             module_sp != m_interpreter_module.lock()) {
445           // If this is a duplicate instance of ld.so, unload it.  We may end up
446           // with it if we load it via a different path than before (symlink
447           // vs real path).
448           // TODO: remove this once we either fix library matching or avoid
449           // loading the interpreter when setting the rendezvous breakpoint.
450           UnloadSections(module_sp);
451           loaded_modules.Remove(module_sp);
452           continue;
453         }
454 
455         loaded_modules.AppendIfNeeded(module_sp);
456         new_modules.Append(module_sp);
457       }
458     }
459     m_process->GetTarget().ModulesDidLoad(new_modules);
460   }
461 
462   if (m_rendezvous.ModulesDidUnload()) {
463     ModuleList old_modules;
464 
465     E = m_rendezvous.unloaded_end();
466     for (I = m_rendezvous.unloaded_begin(); I != E; ++I) {
467       ModuleSpec module_spec{I->file_spec};
468       ModuleSP module_sp = loaded_modules.FindFirstModule(module_spec);
469 
470       if (module_sp.get()) {
471         old_modules.Append(module_sp);
472         UnloadSections(module_sp);
473       }
474     }
475     loaded_modules.Remove(old_modules);
476     m_process->GetTarget().ModulesDidUnload(old_modules, false);
477   }
478 }
479 
480 ThreadPlanSP
GetStepThroughTrampolinePlan(Thread & thread,bool stop)481 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread,
482                                                      bool stop) {
483   ThreadPlanSP thread_plan_sp;
484 
485   StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
486   const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
487   Symbol *sym = context.symbol;
488 
489   if (sym == nullptr || !sym->IsTrampoline())
490     return thread_plan_sp;
491 
492   ConstString sym_name = sym->GetName();
493   if (!sym_name)
494     return thread_plan_sp;
495 
496   SymbolContextList target_symbols;
497   Target &target = thread.GetProcess()->GetTarget();
498   const ModuleList &images = target.GetImages();
499 
500   images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
501   size_t num_targets = target_symbols.GetSize();
502   if (!num_targets)
503     return thread_plan_sp;
504 
505   typedef std::vector<lldb::addr_t> AddressVector;
506   AddressVector addrs;
507   for (size_t i = 0; i < num_targets; ++i) {
508     SymbolContext context;
509     AddressRange range;
510     if (target_symbols.GetContextAtIndex(i, context)) {
511       context.GetAddressRange(eSymbolContextEverything, 0, false, range);
512       lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
513       if (addr != LLDB_INVALID_ADDRESS)
514         addrs.push_back(addr);
515     }
516   }
517 
518   if (addrs.size() > 0) {
519     AddressVector::iterator start = addrs.begin();
520     AddressVector::iterator end = addrs.end();
521 
522     llvm::sort(start, end);
523     addrs.erase(std::unique(start, end), end);
524     thread_plan_sp =
525         std::make_shared<ThreadPlanRunToAddress>(thread, addrs, stop);
526   }
527 
528   return thread_plan_sp;
529 }
530 
LoadVDSO()531 void DynamicLoaderPOSIXDYLD::LoadVDSO() {
532   if (m_vdso_base == LLDB_INVALID_ADDRESS)
533     return;
534 
535   FileSpec file("[vdso]");
536 
537   MemoryRegionInfo info;
538   Status status = m_process->GetMemoryRegionInfo(m_vdso_base, info);
539   if (status.Fail()) {
540     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
541     LLDB_LOG(log, "Failed to get vdso region info: {0}", status);
542     return;
543   }
544 
545   if (ModuleSP module_sp = m_process->ReadModuleFromMemory(
546           file, m_vdso_base, info.GetRange().GetByteSize())) {
547     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_vdso_base, false);
548     m_process->GetTarget().GetImages().AppendIfNeeded(module_sp);
549   }
550 }
551 
LoadInterpreterModule()552 ModuleSP DynamicLoaderPOSIXDYLD::LoadInterpreterModule() {
553   if (m_interpreter_base == LLDB_INVALID_ADDRESS)
554     return nullptr;
555 
556   MemoryRegionInfo info;
557   Target &target = m_process->GetTarget();
558   Status status = m_process->GetMemoryRegionInfo(m_interpreter_base, info);
559   if (status.Fail() || info.GetMapped() != MemoryRegionInfo::eYes ||
560       info.GetName().IsEmpty()) {
561     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
562     LLDB_LOG(log, "Failed to get interpreter region info: {0}", status);
563     return nullptr;
564   }
565 
566   FileSpec file(info.GetName().GetCString());
567   ModuleSpec module_spec(file, target.GetArchitecture());
568 
569   if (ModuleSP module_sp = target.GetOrCreateModule(module_spec,
570                                                     true /* notify */)) {
571     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_interpreter_base,
572                          false);
573     m_interpreter_module = module_sp;
574     return module_sp;
575   }
576   return nullptr;
577 }
578 
LoadAllCurrentModules()579 void DynamicLoaderPOSIXDYLD::LoadAllCurrentModules() {
580   DYLDRendezvous::iterator I;
581   DYLDRendezvous::iterator E;
582   ModuleList module_list;
583   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
584 
585   LoadVDSO();
586 
587   if (!m_rendezvous.Resolve()) {
588     LLDB_LOGF(log,
589               "DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD "
590               "rendezvous address",
591               __FUNCTION__);
592     return;
593   }
594 
595   // The rendezvous class doesn't enumerate the main module, so track that
596   // ourselves here.
597   ModuleSP executable = GetTargetExecutable();
598   m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
599 
600   std::vector<FileSpec> module_names;
601   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
602     module_names.push_back(I->file_spec);
603   m_process->PrefetchModuleSpecs(
604       module_names, m_process->GetTarget().GetArchitecture().GetTriple());
605 
606   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) {
607     ModuleSP module_sp =
608         LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
609     if (module_sp.get()) {
610       LLDB_LOG(log, "LoadAllCurrentModules loading module: {0}",
611                I->file_spec.GetFilename());
612       module_list.Append(module_sp);
613     } else {
614       Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
615       LLDB_LOGF(
616           log,
617           "DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
618           __FUNCTION__, I->file_spec.GetCString(), I->base_addr);
619     }
620   }
621 
622   m_process->GetTarget().ModulesDidLoad(module_list);
623 }
624 
ComputeLoadOffset()625 addr_t DynamicLoaderPOSIXDYLD::ComputeLoadOffset() {
626   addr_t virt_entry;
627 
628   if (m_load_offset != LLDB_INVALID_ADDRESS)
629     return m_load_offset;
630 
631   if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
632     return LLDB_INVALID_ADDRESS;
633 
634   ModuleSP module = m_process->GetTarget().GetExecutableModule();
635   if (!module)
636     return LLDB_INVALID_ADDRESS;
637 
638   ObjectFile *exe = module->GetObjectFile();
639   if (!exe)
640     return LLDB_INVALID_ADDRESS;
641 
642   Address file_entry = exe->GetEntryPointAddress();
643 
644   if (!file_entry.IsValid())
645     return LLDB_INVALID_ADDRESS;
646 
647   m_load_offset = virt_entry - file_entry.GetFileAddress();
648   return m_load_offset;
649 }
650 
EvalSpecialModulesStatus()651 void DynamicLoaderPOSIXDYLD::EvalSpecialModulesStatus() {
652   if (llvm::Optional<uint64_t> vdso_base =
653           m_auxv->GetAuxValue(AuxVector::AUXV_AT_SYSINFO_EHDR))
654     m_vdso_base = *vdso_base;
655 
656   if (llvm::Optional<uint64_t> interpreter_base =
657           m_auxv->GetAuxValue(AuxVector::AUXV_AT_BASE))
658     m_interpreter_base = *interpreter_base;
659 }
660 
GetEntryPoint()661 addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() {
662   if (m_entry_point != LLDB_INVALID_ADDRESS)
663     return m_entry_point;
664 
665   if (m_auxv == nullptr)
666     return LLDB_INVALID_ADDRESS;
667 
668   llvm::Optional<uint64_t> entry_point =
669       m_auxv->GetAuxValue(AuxVector::AUXV_AT_ENTRY);
670   if (!entry_point)
671     return LLDB_INVALID_ADDRESS;
672 
673   m_entry_point = static_cast<addr_t>(*entry_point);
674 
675   const ArchSpec &arch = m_process->GetTarget().GetArchitecture();
676 
677   // On ppc64, the entry point is actually a descriptor.  Dereference it.
678   if (arch.GetMachine() == llvm::Triple::ppc64)
679     m_entry_point = ReadUnsignedIntWithSizeInBytes(m_entry_point, 8);
680 
681   return m_entry_point;
682 }
683 
684 lldb::addr_t
GetThreadLocalData(const lldb::ModuleSP module_sp,const lldb::ThreadSP thread,lldb::addr_t tls_file_addr)685 DynamicLoaderPOSIXDYLD::GetThreadLocalData(const lldb::ModuleSP module_sp,
686                                            const lldb::ThreadSP thread,
687                                            lldb::addr_t tls_file_addr) {
688   auto it = m_loaded_modules.find(module_sp);
689   if (it == m_loaded_modules.end())
690     return LLDB_INVALID_ADDRESS;
691 
692   addr_t link_map = it->second;
693   if (link_map == LLDB_INVALID_ADDRESS)
694     return LLDB_INVALID_ADDRESS;
695 
696   const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
697   if (!metadata.valid)
698     return LLDB_INVALID_ADDRESS;
699 
700   // Get the thread pointer.
701   addr_t tp = thread->GetThreadPointer();
702   if (tp == LLDB_INVALID_ADDRESS)
703     return LLDB_INVALID_ADDRESS;
704 
705   // Find the module's modid.
706   int modid_size = 4; // FIXME(spucci): This isn't right for big-endian 64-bit
707   int64_t modid = ReadUnsignedIntWithSizeInBytes(
708       link_map + metadata.modid_offset, modid_size);
709   if (modid == -1)
710     return LLDB_INVALID_ADDRESS;
711 
712   // Lookup the DTV structure for this thread.
713   addr_t dtv_ptr = tp + metadata.dtv_offset;
714   addr_t dtv = ReadPointer(dtv_ptr);
715   if (dtv == LLDB_INVALID_ADDRESS)
716     return LLDB_INVALID_ADDRESS;
717 
718   // Find the TLS block for this module.
719   addr_t dtv_slot = dtv + metadata.dtv_slot_size * modid;
720   addr_t tls_block = ReadPointer(dtv_slot + metadata.tls_offset);
721 
722   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
723   LLDB_LOGF(log,
724             "DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
725             "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64
726             ", modid=%" PRId64 ", tls_block=0x%" PRIx64 "\n",
727             module_sp->GetObjectName().AsCString(""), link_map, tp,
728             (int64_t)modid, tls_block);
729 
730   if (tls_block == LLDB_INVALID_ADDRESS)
731     return LLDB_INVALID_ADDRESS;
732   else
733     return tls_block + tls_file_addr;
734 }
735 
ResolveExecutableModule(lldb::ModuleSP & module_sp)736 void DynamicLoaderPOSIXDYLD::ResolveExecutableModule(
737     lldb::ModuleSP &module_sp) {
738   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
739 
740   if (m_process == nullptr)
741     return;
742 
743   auto &target = m_process->GetTarget();
744   const auto platform_sp = target.GetPlatform();
745 
746   ProcessInstanceInfo process_info;
747   if (!m_process->GetProcessInfo(process_info)) {
748     LLDB_LOGF(log,
749               "DynamicLoaderPOSIXDYLD::%s - failed to get process info for "
750               "pid %" PRIu64,
751               __FUNCTION__, m_process->GetID());
752     return;
753   }
754 
755   LLDB_LOGF(
756       log, "DynamicLoaderPOSIXDYLD::%s - got executable by pid %" PRIu64 ": %s",
757       __FUNCTION__, m_process->GetID(),
758       process_info.GetExecutableFile().GetPath().c_str());
759 
760   ModuleSpec module_spec(process_info.GetExecutableFile(),
761                          process_info.GetArchitecture());
762   if (module_sp && module_sp->MatchesModuleSpec(module_spec))
763     return;
764 
765   const auto executable_search_paths(Target::GetDefaultExecutableSearchPaths());
766   auto error = platform_sp->ResolveExecutable(
767       module_spec, module_sp,
768       !executable_search_paths.IsEmpty() ? &executable_search_paths : nullptr);
769   if (error.Fail()) {
770     StreamString stream;
771     module_spec.Dump(stream);
772 
773     LLDB_LOGF(log,
774               "DynamicLoaderPOSIXDYLD::%s - failed to resolve executable "
775               "with module spec \"%s\": %s",
776               __FUNCTION__, stream.GetData(), error.AsCString());
777     return;
778   }
779 
780   target.SetExecutableModule(module_sp, eLoadDependentsNo);
781 }
782 
AlwaysRelyOnEHUnwindInfo(lldb_private::SymbolContext & sym_ctx)783 bool DynamicLoaderPOSIXDYLD::AlwaysRelyOnEHUnwindInfo(
784     lldb_private::SymbolContext &sym_ctx) {
785   ModuleSP module_sp;
786   if (sym_ctx.symbol)
787     module_sp = sym_ctx.symbol->GetAddressRef().GetModule();
788   if (!module_sp && sym_ctx.function)
789     module_sp =
790         sym_ctx.function->GetAddressRange().GetBaseAddress().GetModule();
791   if (!module_sp)
792     return false;
793 
794   return module_sp->GetFileSpec().GetPath() == "[vdso]";
795 }
796