blob: 41a93f61004b768f019c829859e39003a686d1c4 [file] [log] [blame]
//===- FuzzerShmemPosix.cpp - Posix shared memory ---------------*- C++ -* ===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// SharedMemoryRegion
//===----------------------------------------------------------------------===//
#include "FuzzerDefs.h"
#if LIBFUZZER_POSIX
#include "FuzzerIO.h"
#include "FuzzerShmem.h"
#include <errno.h>
#include <fcntl.h>
#include <semaphore.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
namespace fuzzer {
std::string SharedMemoryRegion::Path(const char *Name) {
return DirPlusFile(TmpDir(), Name);
}
std::string SharedMemoryRegion::SemName(const char *Name, int Idx) {
std::string Res(Name);
// When passing a name without a leading <slash> character to
// sem_open, the behaviour is unspecified in POSIX. Add a leading
// <slash> character for the name if there is no such one.
if (!Res.empty() && Res[0] != '/')
Res.insert(Res.begin(), '/');
return Res + (char)('0' + Idx);
}
bool SharedMemoryRegion::Map(int fd) {
Data =
(uint8_t *)mmap(0, kShmemSize, PROT_WRITE | PROT_READ, MAP_SHARED, fd, 0);
if (Data == (uint8_t*)-1)
return false;
return true;
}
bool SharedMemoryRegion::Create(const char *Name) {
int fd = open(Path(Name).c_str(), O_CREAT | O_RDWR, 0777);
if (fd < 0) return false;
if (ftruncate(fd, kShmemSize) < 0) return false;
if (!Map(fd))
return false;
for (int i = 0; i < 2; i++) {
sem_unlink(SemName(Name, i).c_str());
Semaphore[i] = sem_open(SemName(Name, i).c_str(), O_CREAT, 0644, 0);
if (Semaphore[i] == SEM_FAILED)
return false;
}
IAmServer = true;
return true;
}
bool SharedMemoryRegion::Open(const char *Name) {
int fd = open(Path(Name).c_str(), O_RDWR);
if (fd < 0) return false;
struct stat stat_res;
if (0 != fstat(fd, &stat_res))
return false;
assert(stat_res.st_size == kShmemSize);
if (!Map(fd))
return false;
for (int i = 0; i < 2; i++) {
Semaphore[i] = sem_open(SemName(Name, i).c_str(), 0);
if (Semaphore[i] == SEM_FAILED)
return false;
}
IAmServer = false;
return true;
}
bool SharedMemoryRegion::Destroy(const char *Name) {
return 0 == unlink(Path(Name).c_str());
}
void SharedMemoryRegion::Post(int Idx) {
assert(Idx == 0 || Idx == 1);
sem_post((sem_t*)Semaphore[Idx]);
}
void SharedMemoryRegion::Wait(int Idx) {
assert(Idx == 0 || Idx == 1);
for (int i = 0; i < 10 && sem_wait((sem_t*)Semaphore[Idx]); i++) {
// sem_wait may fail if interrupted by a signal.
sleep(i);
if (i)
Printf("%s: sem_wait[%d] failed %s\n", i < 9 ? "WARNING" : "ERROR", i,
strerror(errno));
if (i == 9) abort();
}
}
} // namespace fuzzer
#endif // LIBFUZZER_POSIX