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 protected:
59   /// Runtime linker rendezvous structure.
60   DYLDRendezvous m_rendezvous;
61 
62   /// Virtual load address of the inferior process.
63   lldb::addr_t m_load_offset;
64 
65   /// Virtual entry address of the inferior process.
66   lldb::addr_t m_entry_point;
67 
68   /// Auxiliary vector of the inferior process.
69   std::unique_ptr<AuxVector> m_auxv;
70 
71   /// Rendezvous breakpoint.
72   lldb::break_id_t m_dyld_bid;
73 
74   /// Contains AT_SYSINFO_EHDR, which means a vDSO has been
75   /// mapped to the address space
76   lldb::addr_t m_vdso_base;
77 
78   /// Contains AT_BASE, which means a dynamic loader has been
79   /// mapped to the address space
80   lldb::addr_t m_interpreter_base;
81 
82   /// Contains the pointer to the interpret module, if loaded.
83   std::weak_ptr<lldb_private::Module> m_interpreter_module;
84 
85   /// Loaded module list. (link map for each module)
86   std::map<lldb::ModuleWP, lldb::addr_t, std::owner_less<lldb::ModuleWP>>
87       m_loaded_modules;
88 
89   /// If possible sets a breakpoint on a function called by the runtime
90   /// linker each time a module is loaded or unloaded.
91   bool SetRendezvousBreakpoint();
92 
93   /// Callback routine which updates the current list of loaded modules based
94   /// on the information supplied by the runtime linker.
95   static bool RendezvousBreakpointHit(
96       void *baton, lldb_private::StoppointCallbackContext *context,
97       lldb::user_id_t break_id, lldb::user_id_t break_loc_id);
98 
99   /// Indicates whether the initial set of modules was reported added.
100   bool m_initial_modules_added;
101 
102   /// Helper method for RendezvousBreakpointHit.  Updates LLDB's current set
103   /// of loaded modules.
104   void RefreshModules();
105 
106   /// Updates the load address of every allocatable section in \p module.
107   ///
108   /// \param module The module to traverse.
109   ///
110   /// \param link_map_addr The virtual address of the link map for the @p
111   /// module.
112   ///
113   /// \param base_addr The virtual base address \p module is loaded at.
114   void UpdateLoadedSections(lldb::ModuleSP module, lldb::addr_t link_map_addr,
115                             lldb::addr_t base_addr,
116                             bool base_addr_is_offset) override;
117 
118   /// Removes the loaded sections from the target in \p module.
119   ///
120   /// \param module The module to traverse.
121   void UnloadSections(const lldb::ModuleSP module) override;
122 
123   /// Resolves the entry point for the current inferior process and sets a
124   /// breakpoint at that address.
125   void ProbeEntry();
126 
127   /// Callback routine invoked when we hit the breakpoint on process entry.
128   ///
129   /// This routine is responsible for resolving the load addresses of all
130   /// dependent modules required by the inferior and setting up the rendezvous
131   /// breakpoint.
132   static bool
133   EntryBreakpointHit(void *baton,
134                      lldb_private::StoppointCallbackContext *context,
135                      lldb::user_id_t break_id, lldb::user_id_t break_loc_id);
136 
137   /// Helper for the entry breakpoint callback.  Resolves the load addresses
138   /// of all dependent modules.
139   virtual void LoadAllCurrentModules();
140 
141   void LoadVDSO();
142 
143   // Loading an interpreter module (if present) assuming m_interpreter_base
144   // already points to its base address.
145   lldb::ModuleSP LoadInterpreterModule();
146 
147   /// Computes a value for m_load_offset returning the computed address on
148   /// success and LLDB_INVALID_ADDRESS on failure.
149   lldb::addr_t ComputeLoadOffset();
150 
151   /// Computes a value for m_entry_point returning the computed address on
152   /// success and LLDB_INVALID_ADDRESS on failure.
153   lldb::addr_t GetEntryPoint();
154 
155   /// Evaluate if Aux vectors contain vDSO and LD information
156   /// in case they do, read and assign the address to m_vdso_base
157   /// and m_interpreter_base.
158   void EvalSpecialModulesStatus();
159 
160   /// Loads Module from inferior process.
161   void ResolveExecutableModule(lldb::ModuleSP &module_sp);
162 
163   bool AlwaysRelyOnEHUnwindInfo(lldb_private::SymbolContext &sym_ctx) override;
164 
165 private:
166   DynamicLoaderPOSIXDYLD(const DynamicLoaderPOSIXDYLD &) = delete;
167   const DynamicLoaderPOSIXDYLD &
168   operator=(const DynamicLoaderPOSIXDYLD &) = delete;
169 };
170 
171 #endif // LLDB_SOURCE_PLUGINS_DYNAMICLOADER_POSIX_DYLD_DYNAMICLOADERPOSIXDYLD_H
172