1 //===-- DynamicLoaderPOSIXDYLD.h --------------------------------*- C++ -*-===//
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 #ifndef LLDB_SOURCE_PLUGINS_DYNAMICLOADER_POSIX_DYLD_DYNAMICLOADERPOSIXDYLD_H
10 #define LLDB_SOURCE_PLUGINS_DYNAMICLOADER_POSIX_DYLD_DYNAMICLOADERPOSIXDYLD_H
11 
12 #include <map>
13 #include <memory>
14 
15 #include "DYLDRendezvous.h"
16 #include "Plugins/Process/Utility/AuxVector.h"
17 #include "lldb/Breakpoint/StoppointCallbackContext.h"
18 #include "lldb/Core/ModuleList.h"
19 #include "lldb/Target/DynamicLoader.h"
20 
21 class AuxVector;
22 
23 class DynamicLoaderPOSIXDYLD : public lldb_private::DynamicLoader {
24 public:
25   DynamicLoaderPOSIXDYLD(lldb_private::Process *process);
26 
27   ~DynamicLoaderPOSIXDYLD() override;
28 
29   static void Initialize();
30 
31   static void Terminate();
32 
33   static llvm::StringRef GetPluginNameStatic() { return "posix-dyld"; }
34 
35   static llvm::StringRef GetPluginDescriptionStatic();
36 
37   static lldb_private::DynamicLoader *
38   CreateInstance(lldb_private::Process *process, bool force);
39 
40   // DynamicLoader protocol
41 
42   void DidAttach() override;
43 
44   void DidLaunch() override;
45 
46   lldb::ThreadPlanSP GetStepThroughTrampolinePlan(lldb_private::Thread &thread,
47                                                   bool stop_others) override;
48 
49   lldb_private::Status CanLoadImage() override;
50 
51   lldb::addr_t GetThreadLocalData(const lldb::ModuleSP module,
52                                   const lldb::ThreadSP thread,
53                                   lldb::addr_t tls_file_addr) override;
54 
55   // PluginInterface protocol
56   llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
57 
58   lldb::ModuleSP LoadModuleAtAddress(const lldb_private::FileSpec &file,
59                                      lldb::addr_t link_map_addr,
60                                      lldb::addr_t base_addr,
61                                      bool base_addr_is_offset) override;
62 
63 protected:
64   /// Runtime linker rendezvous structure.
65   DYLDRendezvous m_rendezvous;
66 
67   /// Virtual load address of the inferior process.
68   lldb::addr_t m_load_offset;
69 
70   /// Virtual entry address of the inferior process.
71   lldb::addr_t m_entry_point;
72 
73   /// Auxiliary vector of the inferior process.
74   std::unique_ptr<AuxVector> m_auxv;
75 
76   /// Rendezvous breakpoint.
77   lldb::break_id_t m_dyld_bid;
78 
79   /// Contains AT_SYSINFO_EHDR, which means a vDSO has been
80   /// mapped to the address space
81   lldb::addr_t m_vdso_base;
82 
83   /// Contains AT_BASE, which means a dynamic loader has been
84   /// mapped to the address space
85   lldb::addr_t m_interpreter_base;
86 
87   /// Contains the pointer to the interpret module, if loaded.
88   std::weak_ptr<lldb_private::Module> m_interpreter_module;
89 
90   /// Loaded module list. (link map for each module)
91   std::map<lldb::ModuleWP, lldb::addr_t, std::owner_less<lldb::ModuleWP>>
92       m_loaded_modules;
93 
94   /// If possible sets a breakpoint on a function called by the runtime
95   /// linker each time a module is loaded or unloaded.
96   bool SetRendezvousBreakpoint();
97 
98   /// Callback routine which updates the current list of loaded modules based
99   /// on the information supplied by the runtime linker.
100   static bool RendezvousBreakpointHit(
101       void *baton, lldb_private::StoppointCallbackContext *context,
102       lldb::user_id_t break_id, lldb::user_id_t break_loc_id);
103 
104   /// Indicates whether the initial set of modules was reported added.
105   bool m_initial_modules_added;
106 
107   /// Helper method for RendezvousBreakpointHit.  Updates LLDB's current set
108   /// of loaded modules.
109   void RefreshModules();
110 
111   /// Updates the load address of every allocatable section in \p module.
112   ///
113   /// \param module The module to traverse.
114   ///
115   /// \param link_map_addr The virtual address of the link map for the @p
116   /// module.
117   ///
118   /// \param base_addr The virtual base address \p module is loaded at.
119   void UpdateLoadedSections(lldb::ModuleSP module, lldb::addr_t link_map_addr,
120                             lldb::addr_t base_addr,
121                             bool base_addr_is_offset) override;
122 
123   /// Removes the loaded sections from the target in \p module.
124   ///
125   /// \param module The module to traverse.
126   void UnloadSections(const lldb::ModuleSP module) override;
127 
128   /// Resolves the entry point for the current inferior process and sets a
129   /// breakpoint at that address.
130   void ProbeEntry();
131 
132   /// Callback routine invoked when we hit the breakpoint on process entry.
133   ///
134   /// This routine is responsible for resolving the load addresses of all
135   /// dependent modules required by the inferior and setting up the rendezvous
136   /// breakpoint.
137   static bool
138   EntryBreakpointHit(void *baton,
139                      lldb_private::StoppointCallbackContext *context,
140                      lldb::user_id_t break_id, lldb::user_id_t break_loc_id);
141 
142   /// Helper for the entry breakpoint callback.  Resolves the load addresses
143   /// of all dependent modules.
144   virtual void LoadAllCurrentModules();
145 
146   void LoadVDSO();
147 
148   // Loading an interpreter module (if present) assuming m_interpreter_base
149   // already points to its base address.
150   lldb::ModuleSP LoadInterpreterModule();
151 
152   /// Computes a value for m_load_offset returning the computed address on
153   /// success and LLDB_INVALID_ADDRESS on failure.
154   lldb::addr_t ComputeLoadOffset();
155 
156   /// Computes a value for m_entry_point returning the computed address on
157   /// success and LLDB_INVALID_ADDRESS on failure.
158   lldb::addr_t GetEntryPoint();
159 
160   /// Evaluate if Aux vectors contain vDSO and LD information
161   /// in case they do, read and assign the address to m_vdso_base
162   /// and m_interpreter_base.
163   void EvalSpecialModulesStatus();
164 
165   /// Loads Module from inferior process.
166   void ResolveExecutableModule(lldb::ModuleSP &module_sp);
167 
168   bool AlwaysRelyOnEHUnwindInfo(lldb_private::SymbolContext &sym_ctx) override;
169 
170 private:
171   DynamicLoaderPOSIXDYLD(const DynamicLoaderPOSIXDYLD &) = delete;
172   const DynamicLoaderPOSIXDYLD &
173   operator=(const DynamicLoaderPOSIXDYLD &) = delete;
174 };
175 
176 #endif // LLDB_SOURCE_PLUGINS_DYNAMICLOADER_POSIX_DYLD_DYNAMICLOADERPOSIXDYLD_H
177