1 //===-- DynamicLoaderMacOSXDYLD.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 // This is the DynamicLoader plugin for Darwin (macOS / iPhoneOS / tvOS /
10 // watchOS / BridgeOS)
11 // platforms earlier than 2016, where lldb would read the "dyld_all_image_infos"
12 // dyld internal structure to understand where things were loaded and the
13 // solib loaded/unloaded notification function we put a breakpoint on gives us
14 // an array of (load address, mod time, file path) tuples.
15 //
16 // As of late 2016, the new DynamicLoaderMacOS plugin should be used, which uses
17 // dyld SPI functions to get the same information without reading internal dyld
18 // data structures.
19 
20 #ifndef LLDB_SOURCE_PLUGINS_DYNAMICLOADER_MACOSX_DYLD_DYNAMICLOADERMACOSXDYLD_H
21 #define LLDB_SOURCE_PLUGINS_DYNAMICLOADER_MACOSX_DYLD_DYNAMICLOADERMACOSXDYLD_H
22 
23 #include <mutex>
24 #include <vector>
25 
26 #include "lldb/Host/SafeMachO.h"
27 #include "lldb/Target/DynamicLoader.h"
28 #include "lldb/Target/Process.h"
29 #include "lldb/Utility/FileSpec.h"
30 #include "lldb/Utility/StructuredData.h"
31 #include "lldb/Utility/UUID.h"
32 
33 #include "DynamicLoaderDarwin.h"
34 
35 class DynamicLoaderMacOSXDYLD : public lldb_private::DynamicLoaderDarwin {
36 public:
37   DynamicLoaderMacOSXDYLD(lldb_private::Process *process);
38 
39   ~DynamicLoaderMacOSXDYLD() override;
40 
41   // Static Functions
42   static void Initialize();
43 
44   static void Terminate();
45 
46   static lldb_private::ConstString GetPluginNameStatic();
47 
48   static const char *GetPluginDescriptionStatic();
49 
50   static lldb_private::DynamicLoader *
51   CreateInstance(lldb_private::Process *process, bool force);
52 
53   /// Called after attaching a process.
54   ///
55   /// Allow DynamicLoader plug-ins to execute some code after
56   /// attaching to a process.
57   bool ProcessDidExec() override;
58 
59   lldb_private::Status CanLoadImage() override;
60 
61   bool GetSharedCacheInformation(
62       lldb::addr_t &base_address, lldb_private::UUID &uuid,
63       lldb_private::LazyBool &using_shared_cache,
64       lldb_private::LazyBool &private_shared_cache) override;
65 
66   // PluginInterface protocol
67   lldb_private::ConstString GetPluginName() override;
68 
69   uint32_t GetPluginVersion() override;
70 
71   bool IsFullyInitialized() override;
72 
73 protected:
74   void PutToLog(lldb_private::Log *log) const;
75 
76   void DoInitialImageFetch() override;
77 
78   bool NeedToDoInitialImageFetch() override;
79 
80   bool DidSetNotificationBreakpoint() override;
81 
82   void DoClear() override;
83 
84   bool ReadDYLDInfoFromMemoryAndSetNotificationCallback(lldb::addr_t addr);
85 
86   static bool
87   NotifyBreakpointHit(void *baton,
88                       lldb_private::StoppointCallbackContext *context,
89                       lldb::user_id_t break_id, lldb::user_id_t break_loc_id);
90 
91   uint32_t AddrByteSize();
92 
93   bool ReadMachHeader(lldb::addr_t addr, llvm::MachO::mach_header *header,
94                       lldb_private::DataExtractor *load_command_data);
95 
96   uint32_t ParseLoadCommands(const lldb_private::DataExtractor &data,
97                              ImageInfo &dylib_info,
98                              lldb_private::FileSpec *lc_id_dylinker);
99 
100   struct DYLDAllImageInfos {
101     uint32_t version;
102     uint32_t dylib_info_count;            // Version >= 1
103     lldb::addr_t dylib_info_addr;         // Version >= 1
104     lldb::addr_t notification;            // Version >= 1
105     bool processDetachedFromSharedRegion; // Version >= 1
106     bool libSystemInitialized;            // Version >= 2
107     lldb::addr_t dyldImageLoadAddress;    // Version >= 2
108 
109     DYLDAllImageInfos()
110         : version(0), dylib_info_count(0),
111           dylib_info_addr(LLDB_INVALID_ADDRESS),
112           notification(LLDB_INVALID_ADDRESS),
113           processDetachedFromSharedRegion(false), libSystemInitialized(false),
114           dyldImageLoadAddress(LLDB_INVALID_ADDRESS) {}
115 
116     void Clear() {
117       version = 0;
118       dylib_info_count = 0;
119       dylib_info_addr = LLDB_INVALID_ADDRESS;
120       notification = LLDB_INVALID_ADDRESS;
121       processDetachedFromSharedRegion = false;
122       libSystemInitialized = false;
123       dyldImageLoadAddress = LLDB_INVALID_ADDRESS;
124     }
125 
126     bool IsValid() const { return version >= 1 && version <= 6; }
127   };
128 
129   static lldb::ByteOrder GetByteOrderFromMagic(uint32_t magic);
130 
131   bool SetNotificationBreakpoint() override;
132 
133   void ClearNotificationBreakpoint() override;
134 
135   // There is a little tricky bit where you might initially attach while dyld is
136   // updating
137   // the all_image_infos, and you can't read the infos, so you have to continue
138   // and pick it
139   // up when you hit the update breakpoint.  At that point, you need to run this
140   // initialize
141   // function, but when you do it that way you DON'T need to do the extra work
142   // you would at
143   // the breakpoint.
144   // So this function will only do actual work if the image infos haven't been
145   // read yet.
146   // If it does do any work, then it will return true, and false otherwise.
147   // That way you can
148   // call it in the breakpoint action, and if it returns true you're done.
149   bool InitializeFromAllImageInfos();
150 
151   bool ReadAllImageInfosStructure();
152 
153   bool AddModulesUsingImageInfosAddress(lldb::addr_t image_infos_addr,
154                                         uint32_t image_infos_count);
155 
156   bool RemoveModulesUsingImageInfosAddress(lldb::addr_t image_infos_addr,
157                                            uint32_t image_infos_count);
158 
159   void UpdateImageInfosHeaderAndLoadCommands(ImageInfo::collection &image_infos,
160                                              uint32_t infos_count,
161                                              bool update_executable);
162 
163   bool ReadImageInfos(lldb::addr_t image_infos_addr, uint32_t image_infos_count,
164                       ImageInfo::collection &image_infos);
165 
166   lldb::addr_t m_dyld_all_image_infos_addr;
167   DYLDAllImageInfos m_dyld_all_image_infos;
168   uint32_t m_dyld_all_image_infos_stop_id;
169   lldb::user_id_t m_break_id;
170   mutable std::recursive_mutex m_mutex;
171   bool m_process_image_addr_is_all_images_infos;
172 
173 private:
174   DynamicLoaderMacOSXDYLD(const DynamicLoaderMacOSXDYLD &) = delete;
175   const DynamicLoaderMacOSXDYLD &
176   operator=(const DynamicLoaderMacOSXDYLD &) = delete;
177 };
178 
179 #endif // LLDB_SOURCE_PLUGINS_DYNAMICLOADER_MACOSX_DYLD_DYNAMICLOADERMACOSXDYLD_H
180