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