//===-- DynamicLoaderPOSIX.h ------------------------------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // C Includes // C++ Includes // Other libraries and framework includes #include "lldb/Core/PluginManager.h" #include "lldb/Core/Log.h" #include "lldb/Core/Module.h" #include "lldb/Core/ModuleSpec.h" #include "lldb/Target/Platform.h" #include "lldb/Core/Section.h" #include "lldb/Symbol/ObjectFile.h" #include "lldb/Target/Process.h" #include "lldb/Target/Target.h" #include "lldb/Target/Thread.h" #include "lldb/Target/ThreadPlanRunToAddress.h" #include "lldb/Breakpoint/BreakpointLocation.h" #include "AuxVector.h" #include "DynamicLoaderPOSIXDYLD.h" using namespace lldb; using namespace lldb_private; void DynamicLoaderPOSIXDYLD::Initialize() { PluginManager::RegisterPlugin(GetPluginNameStatic(), GetPluginDescriptionStatic(), CreateInstance); } void DynamicLoaderPOSIXDYLD::Terminate() { } lldb_private::ConstString DynamicLoaderPOSIXDYLD::GetPluginName() { return GetPluginNameStatic(); } lldb_private::ConstString DynamicLoaderPOSIXDYLD::GetPluginNameStatic() { static ConstString g_name("linux-dyld"); return g_name; } const char * DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic() { return "Dynamic loader plug-in that watches for shared library " "loads/unloads in POSIX processes."; } uint32_t DynamicLoaderPOSIXDYLD::GetPluginVersion() { return 1; } DynamicLoader * DynamicLoaderPOSIXDYLD::CreateInstance(Process *process, bool force) { bool create = force; if (!create) { const llvm::Triple &triple_ref = process->GetTarget().GetArchitecture().GetTriple(); if (triple_ref.getOS() == llvm::Triple::Linux || triple_ref.getOS() == llvm::Triple::FreeBSD) create = true; } if (create) return new DynamicLoaderPOSIXDYLD (process); return NULL; } DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process) : DynamicLoader(process), m_rendezvous(process), m_load_offset(LLDB_INVALID_ADDRESS), m_entry_point(LLDB_INVALID_ADDRESS), m_auxv(), m_dyld_bid(LLDB_INVALID_BREAK_ID), m_vdso_base(LLDB_INVALID_ADDRESS) { } DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD() { if (m_dyld_bid != LLDB_INVALID_BREAK_ID) { m_process->GetTarget().RemoveBreakpointByID (m_dyld_bid); m_dyld_bid = LLDB_INVALID_BREAK_ID; } } void DynamicLoaderPOSIXDYLD::DidAttach() { Log *log (GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64, __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID); m_auxv.reset(new AuxVector(m_process)); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " reloaded auxv data", __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID); // ask the process if it can load any of its own modules m_process->LoadModules (); ModuleSP executable_sp = GetTargetExecutable (); ResolveExecutableModule (executable_sp); // find the main process load offset addr_t load_offset = ComputeLoadOffset (); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " executable '%s', load_offset 0x%" PRIx64, __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID, executable_sp ? executable_sp->GetFileSpec().GetPath().c_str () : "", load_offset); EvalVdsoStatus(); // if we dont have a load address we cant re-base bool rebase_exec = (load_offset == LLDB_INVALID_ADDRESS) ? false : true; // if we have a valid executable if (executable_sp.get()) { lldb_private::ObjectFile * obj = executable_sp->GetObjectFile(); if (obj) { // don't rebase if the module already has a load address Target & target = m_process->GetTarget (); Address addr = obj->GetImageInfoAddress (&target); if (addr.GetLoadAddress (&target) != LLDB_INVALID_ADDRESS) rebase_exec = false; } } else { // no executable, nothing to re-base rebase_exec = false; } // if the target executable should be re-based if (rebase_exec) { ModuleList module_list; module_list.Append(executable_sp); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " added executable '%s' to module load list", __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID, executable_sp->GetFileSpec().GetPath().c_str ()); UpdateLoadedSections(executable_sp, LLDB_INVALID_ADDRESS, load_offset, true); // When attaching to a target, there are two possible states: // (1) We already crossed the entry point and therefore the rendezvous // structure is ready to be used and we can load the list of modules // and place the rendezvous breakpoint. // (2) We didn't cross the entry point yet, so these structures are not // ready; we should behave as if we just launched the target and // call ProbeEntry(). This will place a breakpoint on the entry // point which itself will be hit after the rendezvous structure is // set up and will perform actions described in (1). if (m_rendezvous.Resolve()) { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64 " rendezvous could resolve: attach assuming dynamic loader info is available now", __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID); LoadAllCurrentModules(); SetRendezvousBreakpoint(); } else { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64 " rendezvous could not yet resolve: adding breakpoint to catch future rendezvous setup", __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID); ProbeEntry(); } m_process->GetTarget().ModulesDidLoad(module_list); if (log) { log->Printf ("DynamicLoaderPOSIXDYLD::%s told the target about the modules that loaded:", __FUNCTION__); for (auto module_sp : module_list.Modules ()) { log->Printf ("-- [module] %s (pid %" PRIu64 ")", module_sp ? module_sp->GetFileSpec().GetPath().c_str () : "", m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID); } } } } void DynamicLoaderPOSIXDYLD::DidLaunch() { Log *log (GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s()", __FUNCTION__); ModuleSP executable; addr_t load_offset; m_auxv.reset(new AuxVector(m_process)); executable = GetTargetExecutable(); load_offset = ComputeLoadOffset(); EvalVdsoStatus(); if (executable.get() && load_offset != LLDB_INVALID_ADDRESS) { ModuleList module_list; module_list.Append(executable); UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset, true); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s about to call ProbeEntry()", __FUNCTION__); ProbeEntry(); m_process->GetTarget().ModulesDidLoad(module_list); } } Error DynamicLoaderPOSIXDYLD::CanLoadImage() { return Error(); } void DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr, addr_t base_addr, bool base_addr_is_offset) { m_loaded_modules[module] = link_map_addr; UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset); } void DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module) { m_loaded_modules.erase(module); UnloadSectionsCommon(module); } void DynamicLoaderPOSIXDYLD::ProbeEntry() { Log *log (GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); const addr_t entry = GetEntryPoint(); if (entry == LLDB_INVALID_ADDRESS) { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " GetEntryPoint() returned no address, not setting entry breakpoint", __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID); return; } if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " GetEntryPoint() returned address 0x%" PRIx64 ", setting entry breakpoint", __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID, entry); if (m_process) { Breakpoint *const entry_break = m_process->GetTarget().CreateBreakpoint(entry, true, false).get(); entry_break->SetCallback(EntryBreakpointHit, this, true); entry_break->SetBreakpointKind("shared-library-event"); // Shoudn't hit this more than once. entry_break->SetOneShot (true); } } // The runtime linker has run and initialized the rendezvous structure once the // process has hit its entry point. When we hit the corresponding breakpoint we // interrogate the rendezvous structure to get the load addresses of all // dependent modules for the process. Similarly, we can discover the runtime // linker function and setup a breakpoint to notify us of any dynamically loaded // modules (via dlopen). bool DynamicLoaderPOSIXDYLD::EntryBreakpointHit(void *baton, StoppointCallbackContext *context, user_id_t break_id, user_id_t break_loc_id) { assert(baton && "null baton"); if (!baton) return false; Log *log (GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); DynamicLoaderPOSIXDYLD *const dyld_instance = static_cast(baton); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64, __FUNCTION__, dyld_instance->m_process ? dyld_instance->m_process->GetID () : LLDB_INVALID_PROCESS_ID); // Disable the breakpoint --- if a stop happens right after this, which we've seen on occasion, we don't // want the breakpoint stepping thread-plan logic to show a breakpoint instruction at the disassembled // entry point to the program. Disabling it prevents it. (One-shot is not enough - one-shot removal logic // only happens after the breakpoint goes public, which wasn't happening in our scenario). if (dyld_instance->m_process) { BreakpointSP breakpoint_sp = dyld_instance->m_process->GetTarget().GetBreakpointByID (break_id); if (breakpoint_sp) { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " disabling breakpoint id %" PRIu64, __FUNCTION__, dyld_instance->m_process->GetID (), break_id); breakpoint_sp->SetEnabled (false); } else { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " failed to find breakpoint for breakpoint id %" PRIu64, __FUNCTION__, dyld_instance->m_process->GetID (), break_id); } } else { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s breakpoint id %" PRIu64 " no Process instance! Cannot disable breakpoint", __FUNCTION__, break_id); } dyld_instance->LoadAllCurrentModules(); dyld_instance->SetRendezvousBreakpoint(); return false; // Continue running. } void DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() { Log *log (GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); addr_t break_addr = m_rendezvous.GetBreakAddress(); Target &target = m_process->GetTarget(); if (m_dyld_bid == LLDB_INVALID_BREAK_ID) { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " setting rendezvous break address at 0x%" PRIx64, __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID, break_addr); Breakpoint *dyld_break = target.CreateBreakpoint (break_addr, true, false).get(); dyld_break->SetCallback(RendezvousBreakpointHit, this, true); dyld_break->SetBreakpointKind ("shared-library-event"); m_dyld_bid = dyld_break->GetID(); } else { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " reusing break id %" PRIu32 ", address at 0x%" PRIx64, __FUNCTION__, m_process ? m_process->GetID () : LLDB_INVALID_PROCESS_ID, m_dyld_bid, break_addr); } // Make sure our breakpoint is at the right address. assert (target.GetBreakpointByID(m_dyld_bid)->FindLocationByAddress(break_addr)->GetBreakpoint().GetID() == m_dyld_bid); } bool DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(void *baton, StoppointCallbackContext *context, user_id_t break_id, user_id_t break_loc_id) { assert (baton && "null baton"); if (!baton) return false; Log *log (GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); DynamicLoaderPOSIXDYLD *const dyld_instance = static_cast(baton); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64, __FUNCTION__, dyld_instance->m_process ? dyld_instance->m_process->GetID () : LLDB_INVALID_PROCESS_ID); dyld_instance->RefreshModules(); // Return true to stop the target, false to just let the target run. const bool stop_when_images_change = dyld_instance->GetStopWhenImagesChange(); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " stop_when_images_change=%s", __FUNCTION__, dyld_instance->m_process ? dyld_instance->m_process->GetID () : LLDB_INVALID_PROCESS_ID, stop_when_images_change ? "true" : "false"); return stop_when_images_change; } void DynamicLoaderPOSIXDYLD::RefreshModules() { if (!m_rendezvous.Resolve()) return; DYLDRendezvous::iterator I; DYLDRendezvous::iterator E; ModuleList &loaded_modules = m_process->GetTarget().GetImages(); if (m_rendezvous.ModulesDidLoad()) { ModuleList new_modules; E = m_rendezvous.loaded_end(); for (I = m_rendezvous.loaded_begin(); I != E; ++I) { ModuleSP module_sp = LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true); if (module_sp.get()) { loaded_modules.AppendIfNeeded(module_sp); new_modules.Append(module_sp); } } m_process->GetTarget().ModulesDidLoad(new_modules); } if (m_rendezvous.ModulesDidUnload()) { ModuleList old_modules; E = m_rendezvous.unloaded_end(); for (I = m_rendezvous.unloaded_begin(); I != E; ++I) { ModuleSpec module_spec{I->file_spec}; ModuleSP module_sp = loaded_modules.FindFirstModule (module_spec); if (module_sp.get()) { old_modules.Append(module_sp); UnloadSections(module_sp); } } loaded_modules.Remove(old_modules); m_process->GetTarget().ModulesDidUnload(old_modules, false); } } ThreadPlanSP DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop) { ThreadPlanSP thread_plan_sp; StackFrame *frame = thread.GetStackFrameAtIndex(0).get(); const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol); Symbol *sym = context.symbol; if (sym == NULL || !sym->IsTrampoline()) return thread_plan_sp; ConstString sym_name = sym->GetName(); if (!sym_name) return thread_plan_sp; SymbolContextList target_symbols; Target &target = thread.GetProcess()->GetTarget(); const ModuleList &images = target.GetImages(); images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols); size_t num_targets = target_symbols.GetSize(); if (!num_targets) return thread_plan_sp; typedef std::vector AddressVector; AddressVector addrs; for (size_t i = 0; i < num_targets; ++i) { SymbolContext context; AddressRange range; if (target_symbols.GetContextAtIndex(i, context)) { context.GetAddressRange(eSymbolContextEverything, 0, false, range); lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target); if (addr != LLDB_INVALID_ADDRESS) addrs.push_back(addr); } } if (addrs.size() > 0) { AddressVector::iterator start = addrs.begin(); AddressVector::iterator end = addrs.end(); std::sort(start, end); addrs.erase(std::unique(start, end), end); thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop)); } return thread_plan_sp; } void DynamicLoaderPOSIXDYLD::LoadAllCurrentModules() { DYLDRendezvous::iterator I; DYLDRendezvous::iterator E; ModuleList module_list; if (!m_rendezvous.Resolve()) { Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); if (log) log->Printf("DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD rendezvous address", __FUNCTION__); return; } // The rendezvous class doesn't enumerate the main module, so track // that ourselves here. ModuleSP executable = GetTargetExecutable(); m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress(); if (m_vdso_base != LLDB_INVALID_ADDRESS) { FileSpec file_spec("[vdso]", false); ModuleSP module_sp = LoadModuleAtAddress(file_spec, LLDB_INVALID_ADDRESS, m_vdso_base, false); if (module_sp.get()) { module_list.Append(module_sp); } } for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) { ModuleSP module_sp = LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true); if (module_sp.get()) { module_list.Append(module_sp); } else { Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); if (log) log->Printf("DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64, __FUNCTION__, I->file_spec.GetCString(), I->base_addr); } } m_process->GetTarget().ModulesDidLoad(module_list); } addr_t DynamicLoaderPOSIXDYLD::ComputeLoadOffset() { addr_t virt_entry; if (m_load_offset != LLDB_INVALID_ADDRESS) return m_load_offset; if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS) return LLDB_INVALID_ADDRESS; ModuleSP module = m_process->GetTarget().GetExecutableModule(); if (!module) return LLDB_INVALID_ADDRESS; ObjectFile *exe = module->GetObjectFile(); if (!exe) return LLDB_INVALID_ADDRESS; Address file_entry = exe->GetEntryPointAddress(); if (!file_entry.IsValid()) return LLDB_INVALID_ADDRESS; m_load_offset = virt_entry - file_entry.GetFileAddress(); return m_load_offset; } void DynamicLoaderPOSIXDYLD::EvalVdsoStatus() { AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AT_SYSINFO_EHDR); if (I != m_auxv->end()) m_vdso_base = I->value; } addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() { if (m_entry_point != LLDB_INVALID_ADDRESS) return m_entry_point; if (m_auxv.get() == NULL) return LLDB_INVALID_ADDRESS; AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AT_ENTRY); if (I == m_auxv->end()) return LLDB_INVALID_ADDRESS; m_entry_point = static_cast(I->value); const ArchSpec &arch = m_process->GetTarget().GetArchitecture(); // On ppc64, the entry point is actually a descriptor. Dereference it. if (arch.GetMachine() == llvm::Triple::ppc64) m_entry_point = ReadUnsignedIntWithSizeInBytes(m_entry_point, 8); return m_entry_point; } lldb::addr_t DynamicLoaderPOSIXDYLD::GetThreadLocalData (const lldb::ModuleSP module, const lldb::ThreadSP thread) { auto it = m_loaded_modules.find (module); if (it == m_loaded_modules.end()) return LLDB_INVALID_ADDRESS; addr_t link_map = it->second; if (link_map == LLDB_INVALID_ADDRESS) return LLDB_INVALID_ADDRESS; const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo(); if (!metadata.valid) return LLDB_INVALID_ADDRESS; // Get the thread pointer. addr_t tp = thread->GetThreadPointer (); if (tp == LLDB_INVALID_ADDRESS) return LLDB_INVALID_ADDRESS; // Find the module's modid. int modid_size = 4; // FIXME(spucci): This isn't right for big-endian 64-bit int64_t modid = ReadUnsignedIntWithSizeInBytes (link_map + metadata.modid_offset, modid_size); if (modid == -1) return LLDB_INVALID_ADDRESS; // Lookup the DTV structure for this thread. addr_t dtv_ptr = tp + metadata.dtv_offset; addr_t dtv = ReadPointer (dtv_ptr); if (dtv == LLDB_INVALID_ADDRESS) return LLDB_INVALID_ADDRESS; // Find the TLS block for this module. addr_t dtv_slot = dtv + metadata.dtv_slot_size*modid; addr_t tls_block = ReadPointer (dtv_slot + metadata.tls_offset); Module *mod = module.get(); Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); if (log) log->Printf("DynamicLoaderPOSIXDYLD::Performed TLS lookup: " "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64 ", modid=%" PRId64 ", tls_block=0x%" PRIx64 "\n", mod->GetObjectName().AsCString(""), link_map, tp, (int64_t)modid, tls_block); return tls_block; } void DynamicLoaderPOSIXDYLD::ResolveExecutableModule (lldb::ModuleSP &module_sp) { Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); if (m_process == nullptr) return; auto &target = m_process->GetTarget (); const auto platform_sp = target.GetPlatform (); ProcessInstanceInfo process_info; if (!m_process->GetProcessInfo(process_info)) { if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s - failed to get process info for pid %" PRIu64, __FUNCTION__, m_process->GetID ()); return; } if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s - got executable by pid %" PRIu64 ": %s", __FUNCTION__, m_process->GetID (), process_info.GetExecutableFile ().GetPath ().c_str ()); ModuleSpec module_spec (process_info.GetExecutableFile (), process_info.GetArchitecture ()); if (module_sp && module_sp->MatchesModuleSpec (module_spec)) return; const auto executable_search_paths (Target::GetDefaultExecutableSearchPaths()); auto error = platform_sp->ResolveExecutable ( module_spec, module_sp, !executable_search_paths.IsEmpty() ? &executable_search_paths : nullptr); if (error.Fail ()) { StreamString stream; module_spec.Dump (stream); if (log) log->Printf ("DynamicLoaderPOSIXDYLD::%s - failed to resolve executable with module spec \"%s\": %s", __FUNCTION__, stream.GetString ().c_str (), error.AsCString ()); return; } target.SetExecutableModule (module_sp, false); }