src/libcompiler_builtins/compiler-rt/lib/fuzzer/FuzzerShmemPosix.cpp

   1 //===- FuzzerShmemPosix.cpp - Posix shared memory ---------------*- 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 // SharedMemoryRegion
  10 //===----------------------------------------------------------------------===//
  11 #include "FuzzerDefs.h"
  12 #if LIBFUZZER_POSIX
  13
  14 #include "FuzzerIO.h"
  15 #include "FuzzerShmem.h"
  16
  17 #include <errno.h>
  18 #include <fcntl.h>
  19 #include <semaphore.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <sys/mman.h>
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #include <unistd.h>
  26
  27 namespace fuzzer {
  28
  29 std::string SharedMemoryRegion::Path(const char *Name) {
  30   return DirPlusFile(TmpDir(), Name);
  31 }
  32
  33 std::string SharedMemoryRegion::SemName(const char *Name, int Idx) {
  34   std::string Res(Name);
  35   return Res + (char)('0' + Idx);
  36 }
  37
  38 bool SharedMemoryRegion::Map(int fd) {
  39   Data =
  40       (uint8_t *)mmap(0, kShmemSize, PROT_WRITE | PROT_READ, MAP_SHARED, fd, 0);
  41   if (Data == (uint8_t*)-1)
  42     return false;
  43   return true;
  44 }
  45
  46 bool SharedMemoryRegion::Create(const char *Name) {
  47   int fd = open(Path(Name).c_str(), O_CREAT | O_RDWR, 0777);
  48   if (fd < 0) return false;
  49   if (ftruncate(fd, kShmemSize) < 0) return false;
  50   if (!Map(fd))
  51     return false;
  52   for (int i = 0; i < 2; i++) {
  53     sem_unlink(SemName(Name, i).c_str());
  54     Semaphore[i] = sem_open(SemName(Name, i).c_str(), O_CREAT, 0644, 0);
  55     if (Semaphore[i] == (void *)-1)
  56       return false;
  57   }
  58   IAmServer = true;
  59   return true;
  60 }
  61
  62 bool SharedMemoryRegion::Open(const char *Name) {
  63   int fd = open(Path(Name).c_str(), O_RDWR);
  64   if (fd < 0) return false;
  65   struct stat stat_res;
  66   if (0 != fstat(fd, &stat_res))
  67     return false;
  68   assert(stat_res.st_size == kShmemSize);
  69   if (!Map(fd))
  70     return false;
  71   for (int i = 0; i < 2; i++) {
  72     Semaphore[i] = sem_open(SemName(Name, i).c_str(), 0);
  73     if (Semaphore[i] == (void *)-1)
  74       return false;
  75   }
  76   IAmServer = false;
  77   return true;
  78 }
  79
  80 bool SharedMemoryRegion::Destroy(const char *Name) {
  81   return 0 == unlink(Path(Name).c_str());
  82 }
  83
  84 void SharedMemoryRegion::Post(int Idx) {
  85   assert(Idx == 0 || Idx == 1);
  86   sem_post((sem_t*)Semaphore[Idx]);
  87 }
  88
  89 void SharedMemoryRegion::Wait(int Idx) {
  90   assert(Idx == 0 || Idx == 1);
  91   for (int i = 0; i < 10 && sem_wait((sem_t*)Semaphore[Idx]); i++) {
  92     // sem_wait may fail if interrupted by a signal.
  93     sleep(i);
  94     if (i)
  95       Printf("%s: sem_wait[%d] failed %s\n", i < 9 ? "WARNING" : "ERROR", i,
  96              strerror(errno));
  97     if (i == 9) abort();
  98   }
  99 }
 100
 101 }  // namespace fuzzer
 102
 103 #endif  // LIBFUZZER_POSIX