libsanitizer/sanitizer_common/sanitizer_procmaps_mac.cc

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