1//===-- DynamicLoaderWindowsDYLD.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 "DynamicLoaderWindowsDYLD.h"
10
11#include "lldb/Core/Module.h"
12#include "lldb/Core/PluginManager.h"
13#include "lldb/Target/ExecutionContext.h"
14#include "lldb/Target/Platform.h"
15#include "lldb/Target/Process.h"
16#include "lldb/Target/RegisterContext.h"
17#include "lldb/Target/Target.h"
18#include "lldb/Target/ThreadPlanStepInstruction.h"
19#include "lldb/Utility/LLDBLog.h"
20#include "lldb/Utility/Log.h"
21
22#include "llvm/TargetParser/Triple.h"
23
24using namespace lldb;
25using namespace lldb_private;
26
27LLDB_PLUGIN_DEFINE(DynamicLoaderWindowsDYLD)
28
29DynamicLoaderWindowsDYLD::DynamicLoaderWindowsDYLD(Process *process)
30 : DynamicLoader(process) {}
31
32DynamicLoaderWindowsDYLD::~DynamicLoaderWindowsDYLD() = default;
33
34void DynamicLoaderWindowsDYLD::Initialize() {
35 PluginManager::RegisterPlugin(name: GetPluginNameStatic(),
36 description: GetPluginDescriptionStatic(), create_callback: CreateInstance);
37}
38
39void DynamicLoaderWindowsDYLD::Terminate() {}
40
41llvm::StringRef DynamicLoaderWindowsDYLD::GetPluginDescriptionStatic() {
42 return "Dynamic loader plug-in that watches for shared library "
43 "loads/unloads in Windows processes.";
44}
45
46DynamicLoader *DynamicLoaderWindowsDYLD::CreateInstance(Process *process,
47 bool force) {
48 bool should_create = force;
49 if (!should_create) {
50 const llvm::Triple &triple_ref =
51 process->GetTarget().GetArchitecture().GetTriple();
52 if (triple_ref.getOS() == llvm::Triple::Win32)
53 should_create = true;
54 }
55
56 if (should_create)
57 return new DynamicLoaderWindowsDYLD(process);
58
59 return nullptr;
60}
61
62void DynamicLoaderWindowsDYLD::OnLoadModule(lldb::ModuleSP module_sp,
63 const ModuleSpec module_spec,
64 lldb::addr_t module_addr) {
65
66 // Resolve the module unless we already have one.
67 if (!module_sp) {
68 Status error;
69 module_sp = m_process->GetTarget().GetOrCreateModule(module_spec,
70 notify: true /* notify */, error_ptr: &error);
71 if (error.Fail())
72 return;
73 }
74
75 m_loaded_modules[module_sp] = module_addr;
76 UpdateLoadedSectionsCommon(module: module_sp, base_addr: module_addr, base_addr_is_offset: false);
77 ModuleList module_list;
78 module_list.Append(module_sp);
79 m_process->GetTarget().ModulesDidLoad(module_list);
80}
81
82void DynamicLoaderWindowsDYLD::OnUnloadModule(lldb::addr_t module_addr) {
83 Address resolved_addr;
84 if (!m_process->GetTarget().ResolveLoadAddress(load_addr: module_addr, so_addr&: resolved_addr))
85 return;
86
87 ModuleSP module_sp = resolved_addr.GetModule();
88 if (module_sp) {
89 m_loaded_modules.erase(x: module_sp);
90 UnloadSectionsCommon(module: module_sp);
91 ModuleList module_list;
92 module_list.Append(module_sp);
93 m_process->GetTarget().ModulesDidUnload(module_list, delete_locations: false);
94 }
95}
96
97lldb::addr_t DynamicLoaderWindowsDYLD::GetLoadAddress(ModuleSP executable) {
98 // First, see if the load address is already cached.
99 auto it = m_loaded_modules.find(x: executable);
100 if (it != m_loaded_modules.end() && it->second != LLDB_INVALID_ADDRESS)
101 return it->second;
102
103 lldb::addr_t load_addr = LLDB_INVALID_ADDRESS;
104
105 // Second, try to get it through the process plugins. For a remote process,
106 // the remote platform will be responsible for providing it.
107 FileSpec file_spec(executable->GetPlatformFileSpec());
108 bool is_loaded = false;
109 Status status =
110 m_process->GetFileLoadAddress(file: file_spec, is_loaded, load_addr);
111 // Servers other than lldb server could respond with a bogus address.
112 if (status.Success() && is_loaded && load_addr != LLDB_INVALID_ADDRESS) {
113 m_loaded_modules[executable] = load_addr;
114 return load_addr;
115 }
116
117 return LLDB_INVALID_ADDRESS;
118}
119
120void DynamicLoaderWindowsDYLD::DidAttach() {
121 Log *log = GetLog(mask: LLDBLog::DynamicLoader);
122 LLDB_LOGF(log, "DynamicLoaderWindowsDYLD::%s()", __FUNCTION__);
123
124 ModuleSP executable = GetTargetExecutable();
125
126 if (!executable.get())
127 return;
128
129 // Try to fetch the load address of the file from the process, since there
130 // could be randomization of the load address.
131 lldb::addr_t load_addr = GetLoadAddress(executable);
132 if (load_addr == LLDB_INVALID_ADDRESS)
133 return;
134
135 // Request the process base address.
136 lldb::addr_t image_base = m_process->GetImageInfoAddress();
137 if (image_base == load_addr)
138 return;
139
140 // Rebase the process's modules if there is a mismatch.
141 UpdateLoadedSections(module: executable, LLDB_INVALID_ADDRESS, base_addr: load_addr, base_addr_is_offset: false);
142
143 ModuleList module_list;
144 module_list.Append(module_sp: executable);
145 m_process->GetTarget().ModulesDidLoad(module_list);
146 auto error = m_process->LoadModules();
147 LLDB_LOG_ERROR(log, std::move(error), "failed to load modules: {0}");
148}
149
150void DynamicLoaderWindowsDYLD::DidLaunch() {
151 Log *log = GetLog(mask: LLDBLog::DynamicLoader);
152 LLDB_LOGF(log, "DynamicLoaderWindowsDYLD::%s()", __FUNCTION__);
153
154 ModuleSP executable = GetTargetExecutable();
155 if (!executable.get())
156 return;
157
158 lldb::addr_t load_addr = GetLoadAddress(executable);
159 if (load_addr != LLDB_INVALID_ADDRESS) {
160 // Update the loaded sections so that the breakpoints can be resolved.
161 UpdateLoadedSections(module: executable, LLDB_INVALID_ADDRESS, base_addr: load_addr, base_addr_is_offset: false);
162
163 ModuleList module_list;
164 module_list.Append(module_sp: executable);
165 m_process->GetTarget().ModulesDidLoad(module_list);
166 auto error = m_process->LoadModules();
167 LLDB_LOG_ERROR(log, std::move(error), "failed to load modules: {0}");
168 }
169}
170
171Status DynamicLoaderWindowsDYLD::CanLoadImage() { return Status(); }
172
173ThreadPlanSP
174DynamicLoaderWindowsDYLD::GetStepThroughTrampolinePlan(Thread &thread,
175 bool stop) {
176 auto arch = m_process->GetTarget().GetArchitecture();
177 if (arch.GetMachine() != llvm::Triple::x86) {
178 return ThreadPlanSP();
179 }
180
181 uint64_t pc = thread.GetRegisterContext()->GetPC();
182 // Max size of an instruction in x86 is 15 bytes.
183 AddressRange range(pc, 2 * 15);
184
185 DisassemblerSP disassembler_sp = Disassembler::DisassembleRange(
186 arch, plugin_name: nullptr, flavor: nullptr, cpu: nullptr, features: nullptr, target&: m_process->GetTarget(), disasm_ranges: range);
187 if (!disassembler_sp) {
188 return ThreadPlanSP();
189 }
190
191 InstructionList *insn_list = &disassembler_sp->GetInstructionList();
192 if (insn_list == nullptr) {
193 return ThreadPlanSP();
194 }
195
196 // First instruction in a x86 Windows trampoline is going to be an indirect
197 // jump through the IAT and the next one will be a nop (usually there for
198 // alignment purposes). e.g.:
199 // 0x70ff4cfc <+956>: jmpl *0x7100c2a8
200 // 0x70ff4d02 <+962>: nop
201
202 auto first_insn = insn_list->GetInstructionAtIndex(idx: 0);
203 auto second_insn = insn_list->GetInstructionAtIndex(idx: 1);
204
205 ExecutionContext exe_ctx(m_process->GetTarget());
206 if (first_insn == nullptr || second_insn == nullptr ||
207 strcmp(s1: first_insn->GetMnemonic(exe_ctx: &exe_ctx), s2: "jmpl") != 0 ||
208 strcmp(s1: second_insn->GetMnemonic(exe_ctx: &exe_ctx), s2: "nop") != 0) {
209 return ThreadPlanSP();
210 }
211
212 assert(first_insn->DoesBranch() && !second_insn->DoesBranch());
213
214 return ThreadPlanSP(new ThreadPlanStepInstruction(
215 thread, false, false, eVoteNoOpinion, eVoteNoOpinion));
216}
217

source code of lldb/source/Plugins/DynamicLoader/Windows-DYLD/DynamicLoaderWindowsDYLD.cpp