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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LIBMEMUNREACHABLE_LEAK_PIPE_H_
#define LIBMEMUNREACHABLE_LEAK_PIPE_H_
#include <sys/socket.h>
#include <vector>
#include "android-base/macros.h"
#include "ScopedPipe.h"
#include "log.h"
namespace android {
// LeakPipe implements a pipe that can transfer vectors of simple objects
// between processes. The pipe is created in the sending process and
// transferred over a socketpair that was created before forking. This ensures
// that only the sending process can have the send side of the pipe open, so if
// the sending process dies the pipe will close.
class LeakPipe {
public:
LeakPipe() {
int ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, sv_);
if (ret < 0) {
MEM_LOG_ALWAYS_FATAL("failed to create socketpair: %s", strerror(errno));
}
}
~LeakPipe() { Close(); }
void Close() {
close(sv_[0]);
close(sv_[1]);
sv_[0] = -1;
sv_[1] = -1;
}
bool OpenReceiver() {
int fd = ReceiveFd(sv_[0]);
if (fd < 0) {
return false;
}
receiver_.SetFd(fd);
return true;
}
bool OpenSender() {
ScopedPipe pipe;
if (!SendFd(sv_[1], pipe.Receiver())) {
return false;
}
pipe.ReleaseReceiver();
sender_.SetFd(pipe.ReleaseSender());
return true;
}
class LeakPipeBase {
public:
LeakPipeBase() : fd_(-1) {}
~LeakPipeBase() { Close(); }
void SetFd(int fd) { fd_ = fd; }
void Close() {
close(fd_);
fd_ = -1;
}
protected:
int fd_;
private:
DISALLOW_COPY_AND_ASSIGN(LeakPipeBase);
};
class LeakPipeSender : public LeakPipeBase {
public:
using LeakPipeBase::LeakPipeBase;
template <typename T>
bool Send(const T& value) {
ssize_t ret = TEMP_FAILURE_RETRY(write(fd_, &value, sizeof(T)));
if (ret < 0) {
MEM_ALOGE("failed to send value: %s", strerror(errno));
return false;
} else if (static_cast<size_t>(ret) != sizeof(T)) {
MEM_ALOGE("eof while writing value");
return false;
}
return true;
}
template <class T, class Alloc = std::allocator<T>>
bool SendVector(const std::vector<T, Alloc>& vector) {
size_t size = vector.size() * sizeof(T);
if (!Send(size)) {
return false;
}
ssize_t ret = TEMP_FAILURE_RETRY(write(fd_, vector.data(), size));
if (ret < 0) {
MEM_ALOGE("failed to send vector: %s", strerror(errno));
return false;
} else if (static_cast<size_t>(ret) != size) {
MEM_ALOGE("eof while writing vector");
return false;
}
return true;
}
};
class LeakPipeReceiver : public LeakPipeBase {
public:
using LeakPipeBase::LeakPipeBase;
template <typename T>
bool Receive(T* value) {
ssize_t ret = TEMP_FAILURE_RETRY(read(fd_, reinterpret_cast<void*>(value), sizeof(T)));
if (ret < 0) {
MEM_ALOGE("failed to receive value: %s", strerror(errno));
return false;
} else if (static_cast<size_t>(ret) != sizeof(T)) {
MEM_ALOGE("eof while receiving value");
return false;
}
return true;
}
template <class T, class Alloc = std::allocator<T>>
bool ReceiveVector(std::vector<T, Alloc>& vector) {
size_t size = 0;
if (!Receive(&size)) {
return false;
}
vector.resize(size / sizeof(T));
char* ptr = reinterpret_cast<char*>(vector.data());
while (size > 0) {
ssize_t ret = TEMP_FAILURE_RETRY(read(fd_, ptr, size));
if (ret < 0) {
MEM_ALOGE("failed to send vector: %s", strerror(errno));
return false;
} else if (ret == 0) {
MEM_ALOGE("eof while reading vector");
return false;
}
size -= ret;
ptr += ret;
}
return true;
}
};
LeakPipeReceiver& Receiver() { return receiver_; }
LeakPipeSender& Sender() { return sender_; }
private:
LeakPipeReceiver receiver_;
LeakPipeSender sender_;
bool SendFd(int sock, int fd);
int ReceiveFd(int sock);
DISALLOW_COPY_AND_ASSIGN(LeakPipe);
int sv_[2];
};
} // namespace android
#endif // LIBMEMUNREACHABLE_LEAK_PIPE_H_
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