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/Target/Process.h"
16 #include "lldb/Target/Target.h"
17 #include "lldb/Target/Thread.h"
18 #include "lldb/Target/ThreadPlanRunToAddress.h"
19 
20 #include "AuxVector.h"
21 #include "DynamicLoaderPOSIXDYLD.h"
22 
23 using namespace lldb;
24 using namespace lldb_private;
25 
26 void
27 DynamicLoaderPOSIXDYLD::Initialize()
28 {
29     PluginManager::RegisterPlugin(GetPluginNameStatic(),
30                                   GetPluginDescriptionStatic(),
31                                   CreateInstance);
32 }
33 
34 void
35 DynamicLoaderPOSIXDYLD::Terminate()
36 {
37 }
38 
39 const char *
40 DynamicLoaderPOSIXDYLD::GetPluginName()
41 {
42     return "DynamicLoaderPOSIXDYLD";
43 }
44 
45 const char *
46 DynamicLoaderPOSIXDYLD::GetShortPluginName()
47 {
48     return "linux-dyld";
49 }
50 
51 const char *
52 DynamicLoaderPOSIXDYLD::GetPluginNameStatic()
53 {
54     return "dynamic-loader.linux-dyld";
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(NULL)
98 {
99 }
100 
101 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD()
102 {
103 }
104 
105 void
106 DynamicLoaderPOSIXDYLD::DidAttach()
107 {
108     ModuleSP executable;
109     addr_t load_offset;
110 
111     m_auxv.reset(new AuxVector(m_process));
112 
113     executable = m_process->GetTarget().GetExecutableModule();
114     load_offset = ComputeLoadOffset();
115 
116     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
117     {
118         ModuleList module_list;
119         module_list.Append(executable);
120         UpdateLoadedSections(executable, load_offset);
121         LoadAllCurrentModules();
122         m_process->GetTarget().ModulesDidLoad(module_list);
123     }
124 }
125 
126 void
127 DynamicLoaderPOSIXDYLD::DidLaunch()
128 {
129     ModuleSP executable;
130     addr_t load_offset;
131 
132     m_auxv.reset(new AuxVector(m_process));
133 
134     executable = m_process->GetTarget().GetExecutableModule();
135     load_offset = ComputeLoadOffset();
136 
137     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
138     {
139         ModuleList module_list;
140         module_list.Append(executable);
141         UpdateLoadedSections(executable, load_offset);
142         ProbeEntry();
143         m_process->GetTarget().ModulesDidLoad(module_list);
144     }
145 }
146 
147 Error
148 DynamicLoaderPOSIXDYLD::ExecutePluginCommand(Args &command, Stream *strm)
149 {
150     return Error();
151 }
152 
153 Log *
154 DynamicLoaderPOSIXDYLD::EnablePluginLogging(Stream *strm, Args &command)
155 {
156     return NULL;
157 }
158 
159 Error
160 DynamicLoaderPOSIXDYLD::CanLoadImage()
161 {
162     return Error();
163 }
164 
165 void
166 DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module, addr_t base_addr)
167 {
168     ObjectFile *obj_file = module->GetObjectFile();
169     SectionList *sections = obj_file->GetSectionList();
170     SectionLoadList &load_list = m_process->GetTarget().GetSectionLoadList();
171     const size_t num_sections = sections->GetSize();
172 
173     for (unsigned i = 0; i < num_sections; ++i)
174     {
175         SectionSP section_sp (sections->GetSectionAtIndex(i));
176         lldb::addr_t new_load_addr = section_sp->GetFileAddress() + base_addr;
177         lldb::addr_t old_load_addr = load_list.GetSectionLoadAddress(section_sp);
178 
179         // If the file address of the section is zero then this is not an
180         // allocatable/loadable section (property of ELF sh_addr).  Skip it.
181         if (new_load_addr == base_addr)
182             continue;
183 
184         if (old_load_addr == LLDB_INVALID_ADDRESS ||
185             old_load_addr != new_load_addr)
186             load_list.SetSectionLoadAddress(section_sp, new_load_addr);
187     }
188 }
189 
190 void
191 DynamicLoaderPOSIXDYLD::ProbeEntry()
192 {
193     Breakpoint *entry_break;
194     addr_t entry;
195 
196     if ((entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
197         return;
198 
199     entry_break = m_process->GetTarget().CreateBreakpoint(entry, true).get();
200     entry_break->SetCallback(EntryBreakpointHit, this, true);
201 }
202 
203 // The runtime linker has run and initialized the rendezvous structure once the
204 // process has hit its entry point.  When we hit the corresponding breakpoint we
205 // interrogate the rendezvous structure to get the load addresses of all
206 // dependent modules for the process.  Similarly, we can discover the runtime
207 // linker function and setup a breakpoint to notify us of any dynamically loaded
208 // modules (via dlopen).
209 bool
210 DynamicLoaderPOSIXDYLD::EntryBreakpointHit(void *baton,
211                                            StoppointCallbackContext *context,
212                                            user_id_t break_id,
213                                            user_id_t break_loc_id)
214 {
215     DynamicLoaderPOSIXDYLD* dyld_instance;
216 
217     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
218     dyld_instance->LoadAllCurrentModules();
219     dyld_instance->SetRendezvousBreakpoint();
220     return false; // Continue running.
221 }
222 
223 void
224 DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint()
225 {
226     Breakpoint *dyld_break;
227     addr_t break_addr;
228 
229     break_addr = m_rendezvous.GetBreakAddress();
230     dyld_break = m_process->GetTarget().CreateBreakpoint(break_addr, true).get();
231     dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
232 }
233 
234 bool
235 DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(void *baton,
236                                                 StoppointCallbackContext *context,
237                                                 user_id_t break_id,
238                                                 user_id_t break_loc_id)
239 {
240     DynamicLoaderPOSIXDYLD* dyld_instance;
241 
242     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
243     dyld_instance->RefreshModules();
244 
245     // Return true to stop the target, false to just let the target run.
246     return dyld_instance->GetStopWhenImagesChange();
247 }
248 
249 void
250 DynamicLoaderPOSIXDYLD::RefreshModules()
251 {
252     if (!m_rendezvous.Resolve())
253         return;
254 
255     DYLDRendezvous::iterator I;
256     DYLDRendezvous::iterator E;
257 
258     ModuleList &loaded_modules = m_process->GetTarget().GetImages();
259 
260     if (m_rendezvous.ModulesDidLoad())
261     {
262         ModuleList new_modules;
263 
264         E = m_rendezvous.loaded_end();
265         for (I = m_rendezvous.loaded_begin(); I != E; ++I)
266         {
267             FileSpec file(I->path.c_str(), true);
268             ModuleSP module_sp = LoadModuleAtAddress(file, I->base_addr);
269             if (module_sp.get())
270                 new_modules.Append(module_sp);
271         }
272         m_process->GetTarget().ModulesDidLoad(new_modules);
273     }
274 
275     if (m_rendezvous.ModulesDidUnload())
276     {
277         ModuleList old_modules;
278 
279         E = m_rendezvous.unloaded_end();
280         for (I = m_rendezvous.unloaded_begin(); I != E; ++I)
281         {
282             FileSpec file(I->path.c_str(), true);
283             ModuleSpec module_spec (file);
284             ModuleSP module_sp =
285                 loaded_modules.FindFirstModule (module_spec);
286             if (module_sp.get())
287                 old_modules.Append(module_sp);
288         }
289         m_process->GetTarget().ModulesDidUnload(old_modules);
290     }
291 }
292 
293 ThreadPlanSP
294 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop)
295 {
296     ThreadPlanSP thread_plan_sp;
297 
298     StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
299     const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
300     Symbol *sym = context.symbol;
301 
302     if (sym == NULL || !sym->IsTrampoline())
303         return thread_plan_sp;
304 
305     const ConstString &sym_name = sym->GetMangled().GetName(Mangled::ePreferMangled);
306     if (!sym_name)
307         return thread_plan_sp;
308 
309     SymbolContextList target_symbols;
310     Target &target = thread.GetProcess()->GetTarget();
311     ModuleList &images = target.GetImages();
312 
313     images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
314     size_t num_targets = target_symbols.GetSize();
315     if (!num_targets)
316         return thread_plan_sp;
317 
318     typedef std::vector<lldb::addr_t> AddressVector;
319     AddressVector addrs;
320     for (size_t i = 0; i < num_targets; ++i)
321     {
322         SymbolContext context;
323         AddressRange range;
324         if (target_symbols.GetContextAtIndex(i, context))
325         {
326             context.GetAddressRange(eSymbolContextEverything, 0, false, range);
327             lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
328             if (addr != LLDB_INVALID_ADDRESS)
329                 addrs.push_back(addr);
330         }
331     }
332 
333     if (addrs.size() > 0)
334     {
335         AddressVector::iterator start = addrs.begin();
336         AddressVector::iterator end = addrs.end();
337 
338         std::sort(start, end);
339         addrs.erase(std::unique(start, end), end);
340         thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop));
341     }
342 
343     return thread_plan_sp;
344 }
345 
346 void
347 DynamicLoaderPOSIXDYLD::LoadAllCurrentModules()
348 {
349     DYLDRendezvous::iterator I;
350     DYLDRendezvous::iterator E;
351     ModuleList module_list;
352 
353     if (!m_rendezvous.Resolve())
354         return;
355 
356     for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
357     {
358         FileSpec file(I->path.c_str(), false);
359         ModuleSP module_sp = LoadModuleAtAddress(file, I->base_addr);
360         if (module_sp.get())
361             module_list.Append(module_sp);
362     }
363 
364     m_process->GetTarget().ModulesDidLoad(module_list);
365 }
366 
367 ModuleSP
368 DynamicLoaderPOSIXDYLD::LoadModuleAtAddress(const FileSpec &file, addr_t base_addr)
369 {
370     Target &target = m_process->GetTarget();
371     ModuleList &modules = target.GetImages();
372     ModuleSP module_sp;
373 
374     ModuleSpec module_spec (file, target.GetArchitecture());
375     if ((module_sp = modules.FindFirstModule (module_spec)))
376     {
377         UpdateLoadedSections(module_sp, base_addr);
378     }
379     else if ((module_sp = target.GetSharedModule(module_spec)))
380     {
381         UpdateLoadedSections(module_sp, base_addr);
382         modules.Append(module_sp);
383     }
384 
385     return module_sp;
386 }
387 
388 addr_t
389 DynamicLoaderPOSIXDYLD::ComputeLoadOffset()
390 {
391     addr_t virt_entry;
392 
393     if (m_load_offset != LLDB_INVALID_ADDRESS)
394         return m_load_offset;
395 
396     if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
397         return LLDB_INVALID_ADDRESS;
398 
399     ModuleSP module = m_process->GetTarget().GetExecutableModule();
400     ObjectFile *exe = module->GetObjectFile();
401     Address file_entry = exe->GetEntryPointAddress();
402 
403     if (!file_entry.IsValid())
404         return LLDB_INVALID_ADDRESS;
405 
406     m_load_offset = virt_entry - file_entry.GetFileAddress();
407     return m_load_offset;
408 }
409 
410 addr_t
411 DynamicLoaderPOSIXDYLD::GetEntryPoint()
412 {
413     if (m_entry_point != LLDB_INVALID_ADDRESS)
414         return m_entry_point;
415 
416     if (m_auxv.get() == NULL)
417         return LLDB_INVALID_ADDRESS;
418 
419     AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AT_ENTRY);
420 
421     if (I == m_auxv->end())
422         return LLDB_INVALID_ADDRESS;
423 
424     m_entry_point = static_cast<addr_t>(I->value);
425     return m_entry_point;
426 }
427