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 27namespace fuzzer { 28 29std::string SharedMemoryRegion::Path(const char *Name) { 30 return DirPlusFile(TmpDir(), Name); 31} 32 33std::string SharedMemoryRegion::SemName(const char *Name, int Idx) { 34 std::string Res(Name); 35 // When passing a name without a leading <slash> character to 36 // sem_open, the behaviour is unspecified in POSIX. Add a leading 37 // <slash> character for the name if there is no such one. 38 if (!Res.empty() && Res[0] != '/') 39 Res.insert(Res.begin(), '/'); 40 return Res + (char)('0' + Idx); 41} 42 43bool SharedMemoryRegion::Map(int fd) { 44 Data = 45 (uint8_t *)mmap(0, kShmemSize, PROT_WRITE | PROT_READ, MAP_SHARED, fd, 0); 46 if (Data == (uint8_t*)-1) 47 return false; 48 return true; 49} 50 51bool SharedMemoryRegion::Create(const char *Name) { 52 int fd = open(Path(Name).c_str(), O_CREAT | O_RDWR, 0777); 53 if (fd < 0) return false; 54 if (ftruncate(fd, kShmemSize) < 0) return false; 55 if (!Map(fd)) 56 return false; 57 for (int i = 0; i < 2; i++) { 58 sem_unlink(SemName(Name, i).c_str()); 59 Semaphore[i] = sem_open(SemName(Name, i).c_str(), O_CREAT, 0644, 0); 60 if (Semaphore[i] == SEM_FAILED) 61 return false; 62 } 63 IAmServer = true; 64 return true; 65} 66 67bool SharedMemoryRegion::Open(const char *Name) { 68 int fd = open(Path(Name).c_str(), O_RDWR); 69 if (fd < 0) return false; 70 struct stat stat_res; 71 if (0 != fstat(fd, &stat_res)) 72 return false; 73 assert(stat_res.st_size == kShmemSize); 74 if (!Map(fd)) 75 return false; 76 for (int i = 0; i < 2; i++) { 77 Semaphore[i] = sem_open(SemName(Name, i).c_str(), 0); 78 if (Semaphore[i] == SEM_FAILED) 79 return false; 80 } 81 IAmServer = false; 82 return true; 83} 84 85bool SharedMemoryRegion::Destroy(const char *Name) { 86 return 0 == unlink(Path(Name).c_str()); 87} 88 89void SharedMemoryRegion::Post(int Idx) { 90 assert(Idx == 0 || Idx == 1); 91 sem_post((sem_t*)Semaphore[Idx]); 92} 93 94void SharedMemoryRegion::Wait(int Idx) { 95 assert(Idx == 0 || Idx == 1); 96 for (int i = 0; i < 10 && sem_wait((sem_t*)Semaphore[Idx]); i++) { 97 // sem_wait may fail if interrupted by a signal. 98 sleep(i); 99 if (i) 100 Printf("%s: sem_wait[%d] failed %s\n", i < 9 ? "WARNING" : "ERROR", i, 101 strerror(errno)); 102 if (i == 9) abort(); 103 } 104} 105 106} // namespace fuzzer 107 108#endif // LIBFUZZER_POSIX 109