1 //===-- DynamicLoaderPOSIX.h ------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // C Includes
11 // C++ Includes
12 // Other libraries and framework includes
13 #include "lldb/Core/PluginManager.h"
14 #include "lldb/Core/Log.h"
15 #include "lldb/Core/Module.h"
16 #include "lldb/Core/ModuleSpec.h"
17 #include "lldb/Core/Section.h"
18 #include "lldb/Symbol/ObjectFile.h"
19 #include "lldb/Target/Process.h"
20 #include "lldb/Target/Target.h"
21 #include "lldb/Target/Thread.h"
22 #include "lldb/Target/ThreadPlanRunToAddress.h"
23 #include "lldb/Breakpoint/BreakpointLocation.h"
24 
25 #include "AuxVector.h"
26 #include "DynamicLoaderPOSIXDYLD.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 
31 void
32 DynamicLoaderPOSIXDYLD::Initialize()
33 {
34     PluginManager::RegisterPlugin(GetPluginNameStatic(),
35                                   GetPluginDescriptionStatic(),
36                                   CreateInstance);
37 }
38 
39 void
40 DynamicLoaderPOSIXDYLD::Terminate()
41 {
42 }
43 
44 lldb_private::ConstString
45 DynamicLoaderPOSIXDYLD::GetPluginName()
46 {
47     return GetPluginNameStatic();
48 }
49 
50 lldb_private::ConstString
51 DynamicLoaderPOSIXDYLD::GetPluginNameStatic()
52 {
53     static ConstString g_name("linux-dyld");
54     return g_name;
55 }
56 
57 const char *
58 DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic()
59 {
60     return "Dynamic loader plug-in that watches for shared library "
61            "loads/unloads in POSIX processes.";
62 }
63 
64 void
65 DynamicLoaderPOSIXDYLD::GetPluginCommandHelp(const char *command, Stream *strm)
66 {
67 }
68 
69 uint32_t
70 DynamicLoaderPOSIXDYLD::GetPluginVersion()
71 {
72     return 1;
73 }
74 
75 DynamicLoader *
76 DynamicLoaderPOSIXDYLD::CreateInstance(Process *process, bool force)
77 {
78     bool create = force;
79     if (!create)
80     {
81         const llvm::Triple &triple_ref = process->GetTarget().GetArchitecture().GetTriple();
82         if (triple_ref.getOS() == llvm::Triple::Linux ||
83             triple_ref.getOS() == llvm::Triple::FreeBSD)
84             create = true;
85     }
86 
87     if (create)
88         return new DynamicLoaderPOSIXDYLD (process);
89     return NULL;
90 }
91 
92 DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process)
93     : DynamicLoader(process),
94       m_rendezvous(process),
95       m_load_offset(LLDB_INVALID_ADDRESS),
96       m_entry_point(LLDB_INVALID_ADDRESS),
97       m_auxv(),
98       m_dyld_bid(LLDB_INVALID_BREAK_ID)
99 {
100 }
101 
102 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD()
103 {
104     if (m_dyld_bid != LLDB_INVALID_BREAK_ID)
105     {
106         m_process->GetTarget().RemoveBreakpointByID (m_dyld_bid);
107         m_dyld_bid = LLDB_INVALID_BREAK_ID;
108     }
109 }
110 
111 void
112 DynamicLoaderPOSIXDYLD::DidAttach()
113 {
114     ModuleSP executable;
115     addr_t load_offset;
116 
117     m_auxv.reset(new AuxVector(m_process));
118 
119     executable = GetTargetExecutable();
120     load_offset = ComputeLoadOffset();
121 
122     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
123     {
124         ModuleList module_list;
125         module_list.Append(executable);
126         UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset);
127         LoadAllCurrentModules();
128         m_process->GetTarget().ModulesDidLoad(module_list);
129     }
130 }
131 
132 void
133 DynamicLoaderPOSIXDYLD::DidLaunch()
134 {
135     ModuleSP executable;
136     addr_t load_offset;
137 
138     m_auxv.reset(new AuxVector(m_process));
139 
140     executable = GetTargetExecutable();
141     load_offset = ComputeLoadOffset();
142 
143     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
144     {
145         ModuleList module_list;
146         module_list.Append(executable);
147         UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset);
148         ProbeEntry();
149         m_process->GetTarget().ModulesDidLoad(module_list);
150     }
151 }
152 
153 ModuleSP
154 DynamicLoaderPOSIXDYLD::GetTargetExecutable()
155 {
156     Target &target = m_process->GetTarget();
157     ModuleSP executable = target.GetExecutableModule();
158 
159     if (executable.get())
160     {
161         if (executable->GetFileSpec().Exists())
162         {
163             ModuleSpec module_spec (executable->GetFileSpec(), executable->GetArchitecture());
164             ModuleSP module_sp (new Module (module_spec));
165 
166             // Check if the executable has changed and set it to the target executable if they differ.
167             if (module_sp.get() && module_sp->GetUUID().IsValid() && executable->GetUUID().IsValid())
168             {
169                 if (module_sp->GetUUID() != executable->GetUUID())
170                     executable.reset();
171             }
172             else if (executable->FileHasChanged())
173             {
174                 executable.reset();
175             }
176 
177             if (!executable.get())
178             {
179                 executable = target.GetSharedModule(module_spec);
180                 if (executable.get() != target.GetExecutableModulePointer())
181                 {
182                     // Don't load dependent images since we are in dyld where we will know
183                     // and find out about all images that are loaded
184                     const bool get_dependent_images = false;
185                     target.SetExecutableModule(executable, get_dependent_images);
186                 }
187             }
188         }
189     }
190     return executable;
191 }
192 
193 Error
194 DynamicLoaderPOSIXDYLD::ExecutePluginCommand(Args &command, Stream *strm)
195 {
196     return Error();
197 }
198 
199 Log *
200 DynamicLoaderPOSIXDYLD::EnablePluginLogging(Stream *strm, Args &command)
201 {
202     return NULL;
203 }
204 
205 Error
206 DynamicLoaderPOSIXDYLD::CanLoadImage()
207 {
208     return Error();
209 }
210 
211 void
212 DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr, addr_t base_addr)
213 {
214     SectionLoadList &load_list = m_process->GetTarget().GetSectionLoadList();
215     const SectionList *sections = GetSectionListFromModule(module);
216 
217     assert(sections && "SectionList missing from loaded module.");
218 
219     m_loaded_modules[module] = link_map_addr;
220 
221     const size_t num_sections = sections->GetSize();
222 
223     for (unsigned i = 0; i < num_sections; ++i)
224     {
225         SectionSP section_sp (sections->GetSectionAtIndex(i));
226         lldb::addr_t new_load_addr = section_sp->GetFileAddress() + base_addr;
227         lldb::addr_t old_load_addr = load_list.GetSectionLoadAddress(section_sp);
228 
229         // If the file address of the section is zero then this is not an
230         // allocatable/loadable section (property of ELF sh_addr).  Skip it.
231         if (new_load_addr == base_addr)
232             continue;
233 
234         if (old_load_addr == LLDB_INVALID_ADDRESS ||
235             old_load_addr != new_load_addr)
236             load_list.SetSectionLoadAddress(section_sp, new_load_addr);
237     }
238 }
239 
240 void
241 DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module)
242 {
243     SectionLoadList &load_list = m_process->GetTarget().GetSectionLoadList();
244     const SectionList *sections = GetSectionListFromModule(module);
245 
246     assert(sections && "SectionList missing from unloaded module.");
247 
248     m_loaded_modules.erase(module);
249 
250     const size_t num_sections = sections->GetSize();
251     for (size_t i = 0; i < num_sections; ++i)
252     {
253         SectionSP section_sp (sections->GetSectionAtIndex(i));
254         load_list.SetSectionUnloaded(section_sp);
255     }
256 }
257 
258 void
259 DynamicLoaderPOSIXDYLD::ProbeEntry()
260 {
261     Breakpoint *entry_break;
262     addr_t entry;
263 
264     if ((entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
265         return;
266 
267     entry_break = m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
268     entry_break->SetCallback(EntryBreakpointHit, this, true);
269     entry_break->SetBreakpointKind("shared-library-event");
270 }
271 
272 // The runtime linker has run and initialized the rendezvous structure once the
273 // process has hit its entry point.  When we hit the corresponding breakpoint we
274 // interrogate the rendezvous structure to get the load addresses of all
275 // dependent modules for the process.  Similarly, we can discover the runtime
276 // linker function and setup a breakpoint to notify us of any dynamically loaded
277 // modules (via dlopen).
278 bool
279 DynamicLoaderPOSIXDYLD::EntryBreakpointHit(void *baton,
280                                            StoppointCallbackContext *context,
281                                            user_id_t break_id,
282                                            user_id_t break_loc_id)
283 {
284     DynamicLoaderPOSIXDYLD* dyld_instance;
285 
286     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
287     dyld_instance->LoadAllCurrentModules();
288     dyld_instance->SetRendezvousBreakpoint();
289     return false; // Continue running.
290 }
291 
292 void
293 DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint()
294 {
295     addr_t break_addr = m_rendezvous.GetBreakAddress();
296     Target &target = m_process->GetTarget();
297 
298     if (m_dyld_bid == LLDB_INVALID_BREAK_ID)
299     {
300         Breakpoint *dyld_break = target.CreateBreakpoint (break_addr, true, false).get();
301         dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
302         dyld_break->SetBreakpointKind ("shared-library-event");
303         m_dyld_bid = dyld_break->GetID();
304     }
305 
306     // Make sure our breakpoint is at the right address.
307     assert (target.GetBreakpointByID(m_dyld_bid)->FindLocationByAddress(break_addr)->GetBreakpoint().GetID() == m_dyld_bid);
308 }
309 
310 bool
311 DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(void *baton,
312                                                 StoppointCallbackContext *context,
313                                                 user_id_t break_id,
314                                                 user_id_t break_loc_id)
315 {
316     DynamicLoaderPOSIXDYLD* dyld_instance;
317 
318     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
319     dyld_instance->RefreshModules();
320 
321     // Return true to stop the target, false to just let the target run.
322     return dyld_instance->GetStopWhenImagesChange();
323 }
324 
325 void
326 DynamicLoaderPOSIXDYLD::RefreshModules()
327 {
328     if (!m_rendezvous.Resolve())
329         return;
330 
331     DYLDRendezvous::iterator I;
332     DYLDRendezvous::iterator E;
333 
334     ModuleList &loaded_modules = m_process->GetTarget().GetImages();
335 
336     if (m_rendezvous.ModulesDidLoad())
337     {
338         ModuleList new_modules;
339 
340         E = m_rendezvous.loaded_end();
341         for (I = m_rendezvous.loaded_begin(); I != E; ++I)
342         {
343             FileSpec file(I->path.c_str(), true);
344             ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, I->base_addr);
345             if (module_sp.get())
346             {
347                 loaded_modules.AppendIfNeeded(module_sp);
348                 new_modules.Append(module_sp);
349             }
350         }
351         m_process->GetTarget().ModulesDidLoad(new_modules);
352     }
353 
354     if (m_rendezvous.ModulesDidUnload())
355     {
356         ModuleList old_modules;
357 
358         E = m_rendezvous.unloaded_end();
359         for (I = m_rendezvous.unloaded_begin(); I != E; ++I)
360         {
361             FileSpec file(I->path.c_str(), true);
362             ModuleSpec module_spec (file);
363             ModuleSP module_sp =
364                 loaded_modules.FindFirstModule (module_spec);
365 
366             if (module_sp.get())
367             {
368                 old_modules.Append(module_sp);
369                 UnloadSections(module_sp);
370             }
371         }
372         loaded_modules.Remove(old_modules);
373         m_process->GetTarget().ModulesDidUnload(old_modules, false);
374     }
375 }
376 
377 ThreadPlanSP
378 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop)
379 {
380     ThreadPlanSP thread_plan_sp;
381 
382     StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
383     const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
384     Symbol *sym = context.symbol;
385 
386     if (sym == NULL || !sym->IsTrampoline())
387         return thread_plan_sp;
388 
389     const ConstString &sym_name = sym->GetMangled().GetName(Mangled::ePreferMangled);
390     if (!sym_name)
391         return thread_plan_sp;
392 
393     SymbolContextList target_symbols;
394     Target &target = thread.GetProcess()->GetTarget();
395     const ModuleList &images = target.GetImages();
396 
397     images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
398     size_t num_targets = target_symbols.GetSize();
399     if (!num_targets)
400         return thread_plan_sp;
401 
402     typedef std::vector<lldb::addr_t> AddressVector;
403     AddressVector addrs;
404     for (size_t i = 0; i < num_targets; ++i)
405     {
406         SymbolContext context;
407         AddressRange range;
408         if (target_symbols.GetContextAtIndex(i, context))
409         {
410             context.GetAddressRange(eSymbolContextEverything, 0, false, range);
411             lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
412             if (addr != LLDB_INVALID_ADDRESS)
413                 addrs.push_back(addr);
414         }
415     }
416 
417     if (addrs.size() > 0)
418     {
419         AddressVector::iterator start = addrs.begin();
420         AddressVector::iterator end = addrs.end();
421 
422         std::sort(start, end);
423         addrs.erase(std::unique(start, end), end);
424         thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop));
425     }
426 
427     return thread_plan_sp;
428 }
429 
430 void
431 DynamicLoaderPOSIXDYLD::LoadAllCurrentModules()
432 {
433     DYLDRendezvous::iterator I;
434     DYLDRendezvous::iterator E;
435     ModuleList module_list;
436 
437     if (!m_rendezvous.Resolve())
438     {
439         Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
440         if (log)
441             log->Printf("DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD rendezvous address",
442                         __FUNCTION__);
443         return;
444     }
445 
446     // The rendezvous class doesn't enumerate the main module, so track
447     // that ourselves here.
448     ModuleSP executable = GetTargetExecutable();
449     m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
450 
451 
452     for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
453     {
454         const char *module_path = I->path.c_str();
455         FileSpec file(module_path, false);
456         ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, I->base_addr);
457         if (module_sp.get())
458         {
459             module_list.Append(module_sp);
460         }
461         else
462         {
463             Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
464             if (log)
465                 log->Printf("DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
466                             __FUNCTION__, module_path, I->base_addr);
467         }
468     }
469 
470     m_process->GetTarget().ModulesDidLoad(module_list);
471 }
472 
473 ModuleSP
474 DynamicLoaderPOSIXDYLD::LoadModuleAtAddress(const FileSpec &file, addr_t link_map_addr, addr_t base_addr)
475 {
476     Target &target = m_process->GetTarget();
477     ModuleList &modules = target.GetImages();
478     ModuleSP module_sp;
479 
480     ModuleSpec module_spec (file, target.GetArchitecture());
481     if ((module_sp = modules.FindFirstModule (module_spec)))
482     {
483         UpdateLoadedSections(module_sp, link_map_addr, base_addr);
484     }
485     else if ((module_sp = target.GetSharedModule(module_spec)))
486     {
487         UpdateLoadedSections(module_sp, link_map_addr, base_addr);
488     }
489 
490     return module_sp;
491 }
492 
493 addr_t
494 DynamicLoaderPOSIXDYLD::ComputeLoadOffset()
495 {
496     addr_t virt_entry;
497 
498     if (m_load_offset != LLDB_INVALID_ADDRESS)
499         return m_load_offset;
500 
501     if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
502         return LLDB_INVALID_ADDRESS;
503 
504     ModuleSP module = m_process->GetTarget().GetExecutableModule();
505     if (!module)
506         return LLDB_INVALID_ADDRESS;
507 
508     ObjectFile *exe = module->GetObjectFile();
509     Address file_entry = exe->GetEntryPointAddress();
510 
511     if (!file_entry.IsValid())
512         return LLDB_INVALID_ADDRESS;
513 
514     m_load_offset = virt_entry - file_entry.GetFileAddress();
515     return m_load_offset;
516 }
517 
518 addr_t
519 DynamicLoaderPOSIXDYLD::GetEntryPoint()
520 {
521     if (m_entry_point != LLDB_INVALID_ADDRESS)
522         return m_entry_point;
523 
524     if (m_auxv.get() == NULL)
525         return LLDB_INVALID_ADDRESS;
526 
527     AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AT_ENTRY);
528 
529     if (I == m_auxv->end())
530         return LLDB_INVALID_ADDRESS;
531 
532     m_entry_point = static_cast<addr_t>(I->value);
533     return m_entry_point;
534 }
535 
536 const SectionList *
537 DynamicLoaderPOSIXDYLD::GetSectionListFromModule(const ModuleSP module) const
538 {
539     SectionList *sections = nullptr;
540     if (module.get())
541     {
542         ObjectFile *obj_file = module->GetObjectFile();
543         if (obj_file)
544         {
545             sections = obj_file->GetSectionList();
546         }
547     }
548     return sections;
549 }
550 
551 static int ReadInt(Process *process, addr_t addr)
552 {
553     Error error;
554     int value = (int)process->ReadUnsignedIntegerFromMemory(addr, sizeof(uint32_t), 0, error);
555     if (error.Fail())
556         return -1;
557     else
558         return value;
559 }
560 
561 static addr_t ReadPointer(Process *process, addr_t addr)
562 {
563     Error error;
564     addr_t value = process->ReadPointerFromMemory(addr, error);
565     if (error.Fail())
566         return LLDB_INVALID_ADDRESS;
567     else
568         return value;
569 }
570 
571 lldb::addr_t
572 DynamicLoaderPOSIXDYLD::GetThreadLocalData (const lldb::ModuleSP module, const lldb::ThreadSP thread)
573 {
574     auto it = m_loaded_modules.find (module);
575     if (it == m_loaded_modules.end())
576         return LLDB_INVALID_ADDRESS;
577 
578     addr_t link_map = it->second;
579     if (link_map == LLDB_INVALID_ADDRESS)
580         return LLDB_INVALID_ADDRESS;
581 
582     const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
583     if (!metadata.valid)
584         return LLDB_INVALID_ADDRESS;
585 
586     // Get the thread pointer.
587     addr_t tp = thread->GetThreadPointer ();
588     if (tp == LLDB_INVALID_ADDRESS)
589         return LLDB_INVALID_ADDRESS;
590 
591     // Find the module's modid.
592     int modid = ReadInt (m_process, link_map + metadata.modid_offset);
593     if (modid == -1)
594         return LLDB_INVALID_ADDRESS;
595 
596     // Lookup the DTV stucture for this thread.
597     addr_t dtv_ptr = tp + metadata.dtv_offset;
598     addr_t dtv = ReadPointer (m_process, dtv_ptr);
599     if (dtv == LLDB_INVALID_ADDRESS)
600         return LLDB_INVALID_ADDRESS;
601 
602     // Find the TLS block for this module.
603     addr_t dtv_slot = dtv + metadata.dtv_slot_size*modid;
604     addr_t tls_block = ReadPointer (m_process, dtv_slot + metadata.tls_offset);
605 
606     Module *mod = module.get();
607     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
608     if (log)
609         log->Printf("DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
610                     "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64 ", modid=%i, tls_block=0x%" PRIx64 "\n",
611                     mod->GetObjectName().AsCString(""), link_map, tp, modid, tls_block);
612 
613     return tls_block;
614 }
615