1 //===-- sanitizer_procmaps_mac.cc -----------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Information about the process mappings (Mac-specific parts).
11 //===----------------------------------------------------------------------===//
12
13 #include "sanitizer_platform.h"
14 #if SANITIZER_MAC
15 #include "sanitizer_common.h"
16 #include "sanitizer_placement_new.h"
17 #include "sanitizer_procmaps.h"
18
19 #include <mach-o/dyld.h>
20 #include <mach-o/loader.h>
21
22 namespace __sanitizer {
23
MemoryMappingLayout(bool cache_enabled)24 MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) {
25 Reset();
26 }
27
~MemoryMappingLayout()28 MemoryMappingLayout::~MemoryMappingLayout() {
29 }
30
31 // More information about Mach-O headers can be found in mach-o/loader.h
32 // Each Mach-O image has a header (mach_header or mach_header_64) starting with
33 // a magic number, and a list of linker load commands directly following the
34 // header.
35 // A load command is at least two 32-bit words: the command type and the
36 // command size in bytes. We're interested only in segment load commands
37 // (LC_SEGMENT and LC_SEGMENT_64), which tell that a part of the file is mapped
38 // into the task's address space.
39 // The |vmaddr|, |vmsize| and |fileoff| fields of segment_command or
40 // segment_command_64 correspond to the memory address, memory size and the
41 // file offset of the current memory segment.
42 // Because these fields are taken from the images as is, one needs to add
43 // _dyld_get_image_vmaddr_slide() to get the actual addresses at runtime.
44
Reset()45 void MemoryMappingLayout::Reset() {
46 // Count down from the top.
47 // TODO(glider): as per man 3 dyld, iterating over the headers with
48 // _dyld_image_count is thread-unsafe. We need to register callbacks for
49 // adding and removing images which will invalidate the MemoryMappingLayout
50 // state.
51 current_image_ = _dyld_image_count();
52 current_load_cmd_count_ = -1;
53 current_load_cmd_addr_ = 0;
54 current_magic_ = 0;
55 current_filetype_ = 0;
56 }
57
58 // static
CacheMemoryMappings()59 void MemoryMappingLayout::CacheMemoryMappings() {
60 // No-op on Mac for now.
61 }
62
LoadFromCache()63 void MemoryMappingLayout::LoadFromCache() {
64 // No-op on Mac for now.
65 }
66
67 // Next and NextSegmentLoad were inspired by base/sysinfo.cc in
68 // Google Perftools, http://code.google.com/p/google-perftools.
69
70 // NextSegmentLoad scans the current image for the next segment load command
71 // and returns the start and end addresses and file offset of the corresponding
72 // segment.
73 // Note that the segment addresses are not necessarily sorted.
74 template<u32 kLCSegment, typename SegmentCommand>
NextSegmentLoad(uptr * start,uptr * end,uptr * offset,char filename[],uptr filename_size,uptr * protection)75 bool MemoryMappingLayout::NextSegmentLoad(
76 uptr *start, uptr *end, uptr *offset,
77 char filename[], uptr filename_size, uptr *protection) {
78 const char* lc = current_load_cmd_addr_;
79 current_load_cmd_addr_ += ((const load_command *)lc)->cmdsize;
80 if (((const load_command *)lc)->cmd == kLCSegment) {
81 const sptr dlloff = _dyld_get_image_vmaddr_slide(current_image_);
82 const SegmentCommand* sc = (const SegmentCommand *)lc;
83 if (start) *start = sc->vmaddr + dlloff;
84 if (protection) {
85 // Return the initial protection.
86 *protection = sc->initprot;
87 }
88 if (end) *end = sc->vmaddr + sc->vmsize + dlloff;
89 if (offset) {
90 if (current_filetype_ == /*MH_EXECUTE*/ 0x2) {
91 *offset = sc->vmaddr;
92 } else {
93 *offset = sc->fileoff;
94 }
95 }
96 if (filename) {
97 internal_strncpy(filename, _dyld_get_image_name(current_image_),
98 filename_size);
99 }
100 return true;
101 }
102 return false;
103 }
104
Next(uptr * start,uptr * end,uptr * offset,char filename[],uptr filename_size,uptr * protection)105 bool MemoryMappingLayout::Next(uptr *start, uptr *end, uptr *offset,
106 char filename[], uptr filename_size,
107 uptr *protection) {
108 for (; current_image_ >= 0; current_image_--) {
109 const mach_header* hdr = _dyld_get_image_header(current_image_);
110 if (!hdr) continue;
111 if (current_load_cmd_count_ < 0) {
112 // Set up for this image;
113 current_load_cmd_count_ = hdr->ncmds;
114 current_magic_ = hdr->magic;
115 current_filetype_ = hdr->filetype;
116 switch (current_magic_) {
117 #ifdef MH_MAGIC_64
118 case MH_MAGIC_64: {
119 current_load_cmd_addr_ = (char*)hdr + sizeof(mach_header_64);
120 break;
121 }
122 #endif
123 case MH_MAGIC: {
124 current_load_cmd_addr_ = (char*)hdr + sizeof(mach_header);
125 break;
126 }
127 default: {
128 continue;
129 }
130 }
131 }
132
133 for (; current_load_cmd_count_ >= 0; current_load_cmd_count_--) {
134 switch (current_magic_) {
135 // current_magic_ may be only one of MH_MAGIC, MH_MAGIC_64.
136 #ifdef MH_MAGIC_64
137 case MH_MAGIC_64: {
138 if (NextSegmentLoad<LC_SEGMENT_64, struct segment_command_64>(
139 start, end, offset, filename, filename_size, protection))
140 return true;
141 break;
142 }
143 #endif
144 case MH_MAGIC: {
145 if (NextSegmentLoad<LC_SEGMENT, struct segment_command>(
146 start, end, offset, filename, filename_size, protection))
147 return true;
148 break;
149 }
150 }
151 }
152 // If we get here, no more load_cmd's in this image talk about
153 // segments. Go on to the next image.
154 }
155 return false;
156 }
157
DumpListOfModules(LoadedModule * modules,uptr max_modules,string_predicate_t filter)158 uptr MemoryMappingLayout::DumpListOfModules(LoadedModule *modules,
159 uptr max_modules,
160 string_predicate_t filter) {
161 Reset();
162 uptr cur_beg, cur_end, prot;
163 InternalScopedBuffer<char> module_name(kMaxPathLength);
164 uptr n_modules = 0;
165 for (uptr i = 0; n_modules < max_modules &&
166 Next(&cur_beg, &cur_end, 0, module_name.data(),
167 module_name.size(), &prot);
168 i++) {
169 const char *cur_name = module_name.data();
170 if (cur_name[0] == '\0')
171 continue;
172 if (filter && !filter(cur_name))
173 continue;
174 LoadedModule *cur_module = 0;
175 if (n_modules > 0 &&
176 0 == internal_strcmp(cur_name, modules[n_modules - 1].full_name())) {
177 cur_module = &modules[n_modules - 1];
178 } else {
179 void *mem = &modules[n_modules];
180 cur_module = new(mem) LoadedModule(cur_name, cur_beg);
181 n_modules++;
182 }
183 cur_module->addAddressRange(cur_beg, cur_end, prot & kProtectionExecute);
184 }
185 return n_modules;
186 }
187
188 } // namespace __sanitizer
189
190 #endif // SANITIZER_MAC
191