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      1 //===-- msan_linux.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 // This file is a part of MemorySanitizer.
     11 //
     12 // Linux-specific code.
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "sanitizer_common/sanitizer_platform.h"
     16 #if SANITIZER_LINUX
     17 
     18 #include "msan.h"
     19 
     20 #include <elf.h>
     21 #include <link.h>
     22 #include <stdio.h>
     23 #include <stdlib.h>
     24 #include <signal.h>
     25 #include <unistd.h>
     26 #include <unwind.h>
     27 #include <execinfo.h>
     28 #include <sys/time.h>
     29 #include <sys/resource.h>
     30 
     31 #include "sanitizer_common/sanitizer_common.h"
     32 #include "sanitizer_common/sanitizer_procmaps.h"
     33 
     34 namespace __msan {
     35 
     36 static const uptr kMemBeg     = 0x600000000000;
     37 static const uptr kMemEnd     = 0x7fffffffffff;
     38 static const uptr kShadowBeg  = MEM_TO_SHADOW(kMemBeg);
     39 static const uptr kShadowEnd  = MEM_TO_SHADOW(kMemEnd);
     40 static const uptr kBad1Beg    = 0x100000000;  // 4G
     41 static const uptr kBad1End    = kShadowBeg - 1;
     42 static const uptr kBad2Beg    = kShadowEnd + 1;
     43 static const uptr kBad2End    = kMemBeg - 1;
     44 static const uptr kOriginsBeg = kBad2Beg;
     45 static const uptr kOriginsEnd = kBad2End;
     46 
     47 bool InitShadow(bool prot1, bool prot2, bool map_shadow, bool init_origins) {
     48   if (flags()->verbosity) {
     49     Printf("__msan_init %p\n", &__msan_init);
     50     Printf("Memory   : %p %p\n", kMemBeg, kMemEnd);
     51     Printf("Bad2     : %p %p\n", kBad2Beg, kBad2End);
     52     Printf("Origins  : %p %p\n", kOriginsBeg, kOriginsEnd);
     53     Printf("Shadow   : %p %p\n", kShadowBeg, kShadowEnd);
     54     Printf("Bad1     : %p %p\n", kBad1Beg, kBad1End);
     55   }
     56 
     57   if (!MemoryRangeIsAvailable(kShadowBeg,
     58                               init_origins ? kOriginsEnd : kShadowEnd)) {
     59     Printf("FATAL: Shadow memory range is not available.\n");
     60     return false;
     61   }
     62 
     63   if (prot1 && !Mprotect(kBad1Beg, kBad1End - kBad1Beg))
     64     return false;
     65   if (prot2 && !Mprotect(kBad2Beg, kBad2End - kBad2Beg))
     66     return false;
     67   if (map_shadow) {
     68     void *shadow = MmapFixedNoReserve(kShadowBeg, kShadowEnd - kShadowBeg);
     69     if (shadow != (void*)kShadowBeg) return false;
     70   }
     71   if (init_origins) {
     72     void *origins = MmapFixedNoReserve(kOriginsBeg, kOriginsEnd - kOriginsBeg);
     73     if (origins != (void*)kOriginsBeg) return false;
     74   }
     75   return true;
     76 }
     77 
     78 void MsanDie() {
     79   _exit(flags()->exit_code);
     80 }
     81 
     82 static void MsanAtExit(void) {
     83   if (msan_report_count > 0) {
     84     ReportAtExitStatistics();
     85     if (flags()->exit_code)
     86       _exit(flags()->exit_code);
     87   }
     88 }
     89 
     90 void InstallAtExitHandler() {
     91   atexit(MsanAtExit);
     92 }
     93 
     94 }  // namespace __msan
     95 
     96 #endif  // __linux__
     97