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, 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, 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 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     const size_t num_sections = sections->GetSize();
220 
221     for (unsigned i = 0; i < num_sections; ++i)
222     {
223         SectionSP section_sp (sections->GetSectionAtIndex(i));
224         lldb::addr_t new_load_addr = section_sp->GetFileAddress() + base_addr;
225         lldb::addr_t old_load_addr = load_list.GetSectionLoadAddress(section_sp);
226 
227         // If the file address of the section is zero then this is not an
228         // allocatable/loadable section (property of ELF sh_addr).  Skip it.
229         if (new_load_addr == base_addr)
230             continue;
231 
232         if (old_load_addr == LLDB_INVALID_ADDRESS ||
233             old_load_addr != new_load_addr)
234             load_list.SetSectionLoadAddress(section_sp, new_load_addr);
235     }
236 }
237 
238 void
239 DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module)
240 {
241     SectionLoadList &load_list = m_process->GetTarget().GetSectionLoadList();
242     const SectionList *sections = GetSectionListFromModule(module);
243 
244     assert(sections && "SectionList missing from unloaded module.");
245 
246     const size_t num_sections = sections->GetSize();
247     for (size_t i = 0; i < num_sections; ++i)
248     {
249         SectionSP section_sp (sections->GetSectionAtIndex(i));
250         load_list.SetSectionUnloaded(section_sp);
251     }
252 }
253 
254 void
255 DynamicLoaderPOSIXDYLD::ProbeEntry()
256 {
257     Breakpoint *entry_break;
258     addr_t entry;
259 
260     if ((entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
261         return;
262 
263     entry_break = m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
264     entry_break->SetCallback(EntryBreakpointHit, this, true);
265     entry_break->SetBreakpointKind("shared-library-event");
266 }
267 
268 // The runtime linker has run and initialized the rendezvous structure once the
269 // process has hit its entry point.  When we hit the corresponding breakpoint we
270 // interrogate the rendezvous structure to get the load addresses of all
271 // dependent modules for the process.  Similarly, we can discover the runtime
272 // linker function and setup a breakpoint to notify us of any dynamically loaded
273 // modules (via dlopen).
274 bool
275 DynamicLoaderPOSIXDYLD::EntryBreakpointHit(void *baton,
276                                            StoppointCallbackContext *context,
277                                            user_id_t break_id,
278                                            user_id_t break_loc_id)
279 {
280     DynamicLoaderPOSIXDYLD* dyld_instance;
281 
282     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
283     dyld_instance->LoadAllCurrentModules();
284     dyld_instance->SetRendezvousBreakpoint();
285     return false; // Continue running.
286 }
287 
288 void
289 DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint()
290 {
291     addr_t break_addr = m_rendezvous.GetBreakAddress();
292     Target &target = m_process->GetTarget();
293 
294     if (m_dyld_bid == LLDB_INVALID_BREAK_ID)
295     {
296         Breakpoint *dyld_break = target.CreateBreakpoint (break_addr, true, false).get();
297         dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
298         dyld_break->SetBreakpointKind ("shared-library-event");
299         m_dyld_bid = dyld_break->GetID();
300     }
301 
302     // Make sure our breakpoint is at the right address.
303     assert (target.GetBreakpointByID(m_dyld_bid)->FindLocationByAddress(break_addr)->GetBreakpoint().GetID() == m_dyld_bid);
304 }
305 
306 bool
307 DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(void *baton,
308                                                 StoppointCallbackContext *context,
309                                                 user_id_t break_id,
310                                                 user_id_t break_loc_id)
311 {
312     DynamicLoaderPOSIXDYLD* dyld_instance;
313 
314     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
315     dyld_instance->RefreshModules();
316 
317     // Return true to stop the target, false to just let the target run.
318     return dyld_instance->GetStopWhenImagesChange();
319 }
320 
321 void
322 DynamicLoaderPOSIXDYLD::RefreshModules()
323 {
324     if (!m_rendezvous.Resolve())
325         return;
326 
327     DYLDRendezvous::iterator I;
328     DYLDRendezvous::iterator E;
329 
330     ModuleList &loaded_modules = m_process->GetTarget().GetImages();
331 
332     if (m_rendezvous.ModulesDidLoad())
333     {
334         ModuleList new_modules;
335 
336         E = m_rendezvous.loaded_end();
337         for (I = m_rendezvous.loaded_begin(); I != E; ++I)
338         {
339             FileSpec file(I->path.c_str(), true);
340             ModuleSP module_sp = LoadModuleAtAddress(file, I->base_addr);
341             if (module_sp.get())
342             {
343                 loaded_modules.AppendIfNeeded(module_sp);
344                 new_modules.Append(module_sp);
345             }
346         }
347         m_process->GetTarget().ModulesDidLoad(new_modules);
348     }
349 
350     if (m_rendezvous.ModulesDidUnload())
351     {
352         ModuleList old_modules;
353 
354         E = m_rendezvous.unloaded_end();
355         for (I = m_rendezvous.unloaded_begin(); I != E; ++I)
356         {
357             FileSpec file(I->path.c_str(), true);
358             ModuleSpec module_spec (file);
359             ModuleSP module_sp =
360                 loaded_modules.FindFirstModule (module_spec);
361 
362             if (module_sp.get())
363             {
364                 old_modules.Append(module_sp);
365                 UnloadSections(module_sp);
366             }
367         }
368         loaded_modules.Remove(old_modules);
369         m_process->GetTarget().ModulesDidUnload(old_modules);
370     }
371 }
372 
373 ThreadPlanSP
374 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop)
375 {
376     ThreadPlanSP thread_plan_sp;
377 
378     StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
379     const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
380     Symbol *sym = context.symbol;
381 
382     if (sym == NULL || !sym->IsTrampoline())
383         return thread_plan_sp;
384 
385     const ConstString &sym_name = sym->GetMangled().GetName(Mangled::ePreferMangled);
386     if (!sym_name)
387         return thread_plan_sp;
388 
389     SymbolContextList target_symbols;
390     Target &target = thread.GetProcess()->GetTarget();
391     const ModuleList &images = target.GetImages();
392 
393     images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
394     size_t num_targets = target_symbols.GetSize();
395     if (!num_targets)
396         return thread_plan_sp;
397 
398     typedef std::vector<lldb::addr_t> AddressVector;
399     AddressVector addrs;
400     for (size_t i = 0; i < num_targets; ++i)
401     {
402         SymbolContext context;
403         AddressRange range;
404         if (target_symbols.GetContextAtIndex(i, context))
405         {
406             context.GetAddressRange(eSymbolContextEverything, 0, false, range);
407             lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
408             if (addr != LLDB_INVALID_ADDRESS)
409                 addrs.push_back(addr);
410         }
411     }
412 
413     if (addrs.size() > 0)
414     {
415         AddressVector::iterator start = addrs.begin();
416         AddressVector::iterator end = addrs.end();
417 
418         std::sort(start, end);
419         addrs.erase(std::unique(start, end), end);
420         thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop));
421     }
422 
423     return thread_plan_sp;
424 }
425 
426 void
427 DynamicLoaderPOSIXDYLD::LoadAllCurrentModules()
428 {
429     DYLDRendezvous::iterator I;
430     DYLDRendezvous::iterator E;
431     ModuleList module_list;
432 
433     if (!m_rendezvous.Resolve())
434     {
435         Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
436         if (log)
437             log->Printf("DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD rendezvous address",
438                         __func__);
439         return;
440     }
441 
442     for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
443     {
444         const char *module_path = I->path.c_str();
445         FileSpec file(module_path, false);
446         ModuleSP module_sp = LoadModuleAtAddress(file, I->base_addr);
447         if (module_sp.get())
448         {
449             module_list.Append(module_sp);
450         }
451         else
452         {
453             Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
454             if (log)
455                 log->Printf("DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
456                             __func__, module_path, I->base_addr);
457         }
458     }
459 
460     m_process->GetTarget().ModulesDidLoad(module_list);
461 }
462 
463 ModuleSP
464 DynamicLoaderPOSIXDYLD::LoadModuleAtAddress(const FileSpec &file, addr_t base_addr)
465 {
466     Target &target = m_process->GetTarget();
467     ModuleList &modules = target.GetImages();
468     ModuleSP module_sp;
469 
470     ModuleSpec module_spec (file, target.GetArchitecture());
471     if ((module_sp = modules.FindFirstModule (module_spec)))
472     {
473         UpdateLoadedSections(module_sp, base_addr);
474     }
475     else if ((module_sp = target.GetSharedModule(module_spec)))
476     {
477         UpdateLoadedSections(module_sp, base_addr);
478     }
479 
480     return module_sp;
481 }
482 
483 addr_t
484 DynamicLoaderPOSIXDYLD::ComputeLoadOffset()
485 {
486     addr_t virt_entry;
487 
488     if (m_load_offset != LLDB_INVALID_ADDRESS)
489         return m_load_offset;
490 
491     if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
492         return LLDB_INVALID_ADDRESS;
493 
494     ModuleSP module = m_process->GetTarget().GetExecutableModule();
495     if (!module)
496         return LLDB_INVALID_ADDRESS;
497 
498     ObjectFile *exe = module->GetObjectFile();
499     Address file_entry = exe->GetEntryPointAddress();
500 
501     if (!file_entry.IsValid())
502         return LLDB_INVALID_ADDRESS;
503 
504     m_load_offset = virt_entry - file_entry.GetFileAddress();
505     return m_load_offset;
506 }
507 
508 addr_t
509 DynamicLoaderPOSIXDYLD::GetEntryPoint()
510 {
511     if (m_entry_point != LLDB_INVALID_ADDRESS)
512         return m_entry_point;
513 
514     if (m_auxv.get() == NULL)
515         return LLDB_INVALID_ADDRESS;
516 
517     AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AT_ENTRY);
518 
519     if (I == m_auxv->end())
520         return LLDB_INVALID_ADDRESS;
521 
522     m_entry_point = static_cast<addr_t>(I->value);
523     return m_entry_point;
524 }
525 
526 const SectionList *
527 DynamicLoaderPOSIXDYLD::GetSectionListFromModule(const ModuleSP module) const
528 {
529     SectionList *sections = nullptr;
530     if (module.get())
531     {
532         ObjectFile *obj_file = module->GetObjectFile();
533         if (obj_file)
534         {
535             sections = obj_file->GetSectionList();
536         }
537     }
538     return sections;
539 }
540