libsanitizer/sanitizer_common/sanitizer_procmaps.h

   1 //===-- sanitizer_procmaps.h ------------------------------------*- C++ -*-===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is shared between AddressSanitizer and ThreadSanitizer.
   9 //
  10 // Information about the process mappings.
  11 //===----------------------------------------------------------------------===//
  12 #ifndef SANITIZER_PROCMAPS_H
  13 #define SANITIZER_PROCMAPS_H
  14
  15 #include "sanitizer_internal_defs.h"
  16 #include "sanitizer_mutex.h"
  17
  18 namespace __sanitizer {
  19
  20 #ifdef _WIN32
  21 class MemoryMappingLayout {
  22  public:
  23   MemoryMappingLayout() {}
  24   bool GetObjectNameAndOffset(uptr addr, uptr *offset,
  25                               char filename[], uptr filename_size) {
  26     UNIMPLEMENTED();
  27   }
  28 };
  29
  30 #else  // _WIN32
  31 #if defined(__linux__)
  32 struct ProcSelfMapsBuff {
  33   char *data;
  34   uptr mmaped_size;
  35   uptr len;
  36 };
  37 #endif  // defined(__linux__)
  38
  39 class MemoryMappingLayout {
  40  public:
  41   MemoryMappingLayout();
  42   bool Next(uptr *start, uptr *end, uptr *offset,
  43             char filename[], uptr filename_size);
  44   void Reset();
  45   // Gets the object file name and the offset in that object for a given
  46   // address 'addr'. Returns true on success.
  47   bool GetObjectNameAndOffset(uptr addr, uptr *offset,
  48                               char filename[], uptr filename_size);
  49   // In some cases, e.g. when running under a sandbox on Linux, ASan is unable
  50   // to obtain the memory mappings. It should fall back to pre-cached data
  51   // instead of aborting.
  52   static void CacheMemoryMappings();
  53   ~MemoryMappingLayout();
  54
  55  private:
  56   void LoadFromCache();
  57   // Default implementation of GetObjectNameAndOffset.
  58   // Quite slow, because it iterates through the whole process map for each
  59   // lookup.
  60   bool IterateForObjectNameAndOffset(uptr addr, uptr *offset,
  61                                      char filename[], uptr filename_size) {
  62     Reset();
  63     uptr start, end, file_offset;
  64     for (int i = 0; Next(&start, &end, &file_offset, filename, filename_size);
  65          i++) {
  66       if (addr >= start && addr < end) {
  67         // Don't subtract 'start' for the first entry:
  68         // * If a binary is compiled w/o -pie, then the first entry in
  69         //   process maps is likely the binary itself (all dynamic libs
  70         //   are mapped higher in address space). For such a binary,
  71         //   instruction offset in binary coincides with the actual
  72         //   instruction address in virtual memory (as code section
  73         //   is mapped to a fixed memory range).
  74         // * If a binary is compiled with -pie, all the modules are
  75         //   mapped high at address space (in particular, higher than
  76         //   shadow memory of the tool), so the module can't be the
  77         //   first entry.
  78         *offset = (addr - (i ? start : 0)) + file_offset;
  79         return true;
  80       }
  81     }
  82     if (filename_size)
  83       filename[0] = '\0';
  84     return false;
  85   }
  86
  87 # if defined __linux__
  88   ProcSelfMapsBuff proc_self_maps_;
  89   char *current_;
  90
  91   // Static mappings cache.
  92   static ProcSelfMapsBuff cached_proc_self_maps_;
  93   static StaticSpinMutex cache_lock_;  // protects cached_proc_self_maps_.
  94 # elif defined __APPLE__
  95   template<u32 kLCSegment, typename SegmentCommand>
  96   bool NextSegmentLoad(uptr *start, uptr *end, uptr *offset,
  97                        char filename[], uptr filename_size);
  98   int current_image_;
  99   u32 current_magic_;
 100   u32 current_filetype_;
 101   int current_load_cmd_count_;
 102   char *current_load_cmd_addr_;
 103 # endif
 104 };
 105
 106 #endif  // _WIN32
 107
 108 }  // namespace __sanitizer
 109
 110 #endif  // SANITIZER_PROCMAPS_H