1 //===-- DynamicLoader.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 #include "lldb/Target/DynamicLoader.h"
10 
11 #include "lldb/Core/Module.h"
12 #include "lldb/Core/ModuleList.h"
13 #include "lldb/Core/ModuleSpec.h"
14 #include "lldb/Core/PluginManager.h"
15 #include "lldb/Core/Section.h"
16 #include "lldb/Symbol/ObjectFile.h"
17 #include "lldb/Target/MemoryRegionInfo.h"
18 #include "lldb/Target/Process.h"
19 #include "lldb/Target/Target.h"
20 #include "lldb/Utility/ConstString.h"
21 #include "lldb/lldb-private-interfaces.h"
22 
23 #include "llvm/ADT/StringRef.h"
24 
25 #include <memory>
26 
27 #include <cassert>
28 
29 using namespace lldb;
30 using namespace lldb_private;
31 
32 DynamicLoader *DynamicLoader::FindPlugin(Process *process,
33                                          llvm::StringRef plugin_name) {
34   DynamicLoaderCreateInstance create_callback = nullptr;
35   if (!plugin_name.empty()) {
36     create_callback =
37         PluginManager::GetDynamicLoaderCreateCallbackForPluginName(plugin_name);
38     if (create_callback) {
39       std::unique_ptr<DynamicLoader> instance_up(
40           create_callback(process, true));
41       if (instance_up)
42         return instance_up.release();
43     }
44   } else {
45     for (uint32_t idx = 0;
46          (create_callback =
47               PluginManager::GetDynamicLoaderCreateCallbackAtIndex(idx)) !=
48          nullptr;
49          ++idx) {
50       std::unique_ptr<DynamicLoader> instance_up(
51           create_callback(process, false));
52       if (instance_up)
53         return instance_up.release();
54     }
55   }
56   return nullptr;
57 }
58 
59 DynamicLoader::DynamicLoader(Process *process) : m_process(process) {}
60 
61 // Accessosors to the global setting as to whether to stop at image (shared
62 // library) loading/unloading.
63 
64 bool DynamicLoader::GetStopWhenImagesChange() const {
65   return m_process->GetStopOnSharedLibraryEvents();
66 }
67 
68 void DynamicLoader::SetStopWhenImagesChange(bool stop) {
69   m_process->SetStopOnSharedLibraryEvents(stop);
70 }
71 
72 ModuleSP DynamicLoader::GetTargetExecutable() {
73   Target &target = m_process->GetTarget();
74   ModuleSP executable = target.GetExecutableModule();
75 
76   if (executable) {
77     if (FileSystem::Instance().Exists(executable->GetFileSpec())) {
78       ModuleSpec module_spec(executable->GetFileSpec(),
79                              executable->GetArchitecture());
80       auto module_sp = std::make_shared<Module>(module_spec);
81 
82       // Check if the executable has changed and set it to the target
83       // executable if they differ.
84       if (module_sp && module_sp->GetUUID().IsValid() &&
85           executable->GetUUID().IsValid()) {
86         if (module_sp->GetUUID() != executable->GetUUID())
87           executable.reset();
88       } else if (executable->FileHasChanged()) {
89         executable.reset();
90       }
91 
92       if (!executable) {
93         executable = target.GetOrCreateModule(module_spec, true /* notify */);
94         if (executable.get() != target.GetExecutableModulePointer()) {
95           // Don't load dependent images since we are in dyld where we will
96           // know and find out about all images that are loaded
97           target.SetExecutableModule(executable, eLoadDependentsNo);
98         }
99       }
100     }
101   }
102   return executable;
103 }
104 
105 void DynamicLoader::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr,
106                                          addr_t base_addr,
107                                          bool base_addr_is_offset) {
108   UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
109 }
110 
111 void DynamicLoader::UpdateLoadedSectionsCommon(ModuleSP module,
112                                                addr_t base_addr,
113                                                bool base_addr_is_offset) {
114   bool changed;
115   module->SetLoadAddress(m_process->GetTarget(), base_addr, base_addr_is_offset,
116                          changed);
117 }
118 
119 void DynamicLoader::UnloadSections(const ModuleSP module) {
120   UnloadSectionsCommon(module);
121 }
122 
123 void DynamicLoader::UnloadSectionsCommon(const ModuleSP module) {
124   Target &target = m_process->GetTarget();
125   const SectionList *sections = GetSectionListFromModule(module);
126 
127   assert(sections && "SectionList missing from unloaded module.");
128 
129   const size_t num_sections = sections->GetSize();
130   for (size_t i = 0; i < num_sections; ++i) {
131     SectionSP section_sp(sections->GetSectionAtIndex(i));
132     target.SetSectionUnloaded(section_sp);
133   }
134 }
135 
136 const SectionList *
137 DynamicLoader::GetSectionListFromModule(const ModuleSP module) const {
138   SectionList *sections = nullptr;
139   if (module) {
140     ObjectFile *obj_file = module->GetObjectFile();
141     if (obj_file != nullptr) {
142       sections = obj_file->GetSectionList();
143     }
144   }
145   return sections;
146 }
147 
148 ModuleSP DynamicLoader::FindModuleViaTarget(const FileSpec &file) {
149   Target &target = m_process->GetTarget();
150   ModuleSpec module_spec(file, target.GetArchitecture());
151 
152   if (ModuleSP module_sp = target.GetImages().FindFirstModule(module_spec))
153     return module_sp;
154 
155   if (ModuleSP module_sp = target.GetOrCreateModule(module_spec, false))
156     return module_sp;
157 
158   return nullptr;
159 }
160 
161 ModuleSP DynamicLoader::LoadModuleAtAddress(const FileSpec &file,
162                                             addr_t link_map_addr,
163                                             addr_t base_addr,
164                                             bool base_addr_is_offset) {
165   if (ModuleSP module_sp = FindModuleViaTarget(file)) {
166     UpdateLoadedSections(module_sp, link_map_addr, base_addr,
167                          base_addr_is_offset);
168     return module_sp;
169   }
170 
171   return nullptr;
172 }
173 
174 int64_t DynamicLoader::ReadUnsignedIntWithSizeInBytes(addr_t addr,
175                                                       int size_in_bytes) {
176   Status error;
177   uint64_t value =
178       m_process->ReadUnsignedIntegerFromMemory(addr, size_in_bytes, 0, error);
179   if (error.Fail())
180     return -1;
181   else
182     return (int64_t)value;
183 }
184 
185 addr_t DynamicLoader::ReadPointer(addr_t addr) {
186   Status error;
187   addr_t value = m_process->ReadPointerFromMemory(addr, error);
188   if (error.Fail())
189     return LLDB_INVALID_ADDRESS;
190   else
191     return value;
192 }
193 
194 void DynamicLoader::LoadOperatingSystemPlugin(bool flush)
195 {
196     if (m_process)
197         m_process->LoadOperatingSystemPlugin(flush);
198 }
199 
200