lib/sanitizer_common/sanitizer_procmaps.h

   1 //===-- sanitizer_procmaps.h ------------------------------------*- C++ -*-===//
   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 // This file is shared between AddressSanitizer and ThreadSanitizer.
  11 //
  12 // Information about the process mappings.
  13 //===----------------------------------------------------------------------===//
  14 #ifndef SANITIZER_PROCMAPS_H
  15 #define SANITIZER_PROCMAPS_H
  16
  17 #include "sanitizer_internal_defs.h"
  18 #include "sanitizer_mutex.h"
  19
  20 namespace __sanitizer {
  21
  22 #ifdef _WIN32
  23 class MemoryMappingLayout {
  24  public:
  25   MemoryMappingLayout() {}
  26   bool GetObjectNameAndOffset(uptr addr, uptr *offset,
  27                               char filename[], uptr filename_size) {
  28     UNIMPLEMENTED();
  29   }
  30 };
  31
  32 #else  // _WIN32
  33 #if defined(__linux__)
  34 struct ProcSelfMapsBuff {
  35   char *data;
  36   uptr mmaped_size;
  37   uptr len;
  38 };
  39 #endif  // defined(__linux__)
  40
  41 class MemoryMappingLayout {
  42  public:
  43   MemoryMappingLayout();
  44   bool Next(uptr *start, uptr *end, uptr *offset,
  45             char filename[], uptr filename_size);
  46   void Reset();
  47   // Gets the object file name and the offset in that object for a given
  48   // address 'addr'. Returns true on success.
  49   bool GetObjectNameAndOffset(uptr addr, uptr *offset,
  50                               char filename[], uptr filename_size);
  51   // In some cases, e.g. when running under a sandbox on Linux, ASan is unable
  52   // to obtain the memory mappings. It should fall back to pre-cached data
  53   // instead of aborting.
  54   static void CacheMemoryMappings();
  55   ~MemoryMappingLayout();
  56
  57  private:
  58   void LoadFromCache();
  59   // Default implementation of GetObjectNameAndOffset.
  60   // Quite slow, because it iterates through the whole process map for each
  61   // lookup.
  62   bool IterateForObjectNameAndOffset(uptr addr, uptr *offset,
  63                                      char filename[], uptr filename_size) {
  64     Reset();
  65     uptr start, end, file_offset;
  66     for (int i = 0; Next(&start, &end, &file_offset, filename, filename_size);
  67          i++) {
  68       if (addr >= start && addr < end) {
  69         // Don't subtract 'start' for the first entry:
  70         // * If a binary is compiled w/o -pie, then the first entry in
  71         //   process maps is likely the binary itself (all dynamic libs
  72         //   are mapped higher in address space). For such a binary,
  73         //   instruction offset in binary coincides with the actual
  74         //   instruction address in virtual memory (as code section
  75         //   is mapped to a fixed memory range).
  76         // * If a binary is compiled with -pie, all the modules are
  77         //   mapped high at address space (in particular, higher than
  78         //   shadow memory of the tool), so the module can't be the
  79         //   first entry.
  80         *offset = (addr - (i ? start : 0)) + file_offset;
  81         return true;
  82       }
  83     }
  84     if (filename_size)
  85       filename[0] = '\0';
  86     return false;
  87   }
  88
  89 # if defined __linux__
  90   ProcSelfMapsBuff proc_self_maps_;
  91   char *current_;
  92
  93   // Static mappings cache.
  94   static ProcSelfMapsBuff cached_proc_self_maps_;
  95   static StaticSpinMutex cache_lock_;  // protects cached_proc_self_maps_.
  96 # elif defined __APPLE__
  97   template<u32 kLCSegment, typename SegmentCommand>
  98   bool NextSegmentLoad(uptr *start, uptr *end, uptr *offset,
  99                        char filename[], uptr filename_size);
 100   int current_image_;
 101   u32 current_magic_;
 102   u32 current_filetype_;
 103   int current_load_cmd_count_;
 104   char *current_load_cmd_addr_;
 105 # endif
 106 };
 107
 108 #endif  // _WIN32
 109
 110 }  // namespace __sanitizer
 111
 112 #endif  // SANITIZER_PROCMAPS_H