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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_POSIX_UNIX_DOMAIN_SOCKET_LINUX_H_
#define BASE_POSIX_UNIX_DOMAIN_SOCKET_LINUX_H_
#include <stdint.h>
#include <sys/types.h>
#include <vector>
#include "base/base_export.h"
class Pickle;
class BASE_EXPORT UnixDomainSocket {
public:
// Maximum number of file descriptors that can be read by RecvMsg().
static const size_t kMaxFileDescriptors;
// Use sendmsg to write the given msg and include a vector of file
// descriptors. Returns true if successful.
static bool SendMsg(int fd,
const void* msg,
size_t length,
const std::vector<int>& fds);
// Use recvmsg to read a message and an array of file descriptors. Returns
// -1 on failure. Note: will read, at most, |kMaxFileDescriptors| descriptors.
static ssize_t RecvMsg(int fd,
void* msg,
size_t length,
std::vector<int>* fds);
// Perform a sendmsg/recvmsg pair.
// 1. This process creates a UNIX SEQPACKET socketpair. Using
// connection-oriented sockets (SEQPACKET or STREAM) is critical here,
// because if one of the ends closes the other one must be notified.
// 2. This process writes a request to |fd| with an SCM_RIGHTS control
// message containing on end of the fresh socket pair.
// 3. This process blocks reading from the other end of the fresh
// socketpair.
// 4. The target process receives the request, processes it and writes the
// reply to the end of the socketpair contained in the request.
// 5. This process wakes up and continues.
//
// fd: descriptor to send the request on
// reply: buffer for the reply
// reply_len: size of |reply|
// result_fd: (may be NULL) the file descriptor returned in the reply
// (if any)
// request: the bytes to send in the request
static ssize_t SendRecvMsg(int fd,
uint8_t* reply,
unsigned reply_len,
int* result_fd,
const Pickle& request);
// Similar to SendRecvMsg(), but |recvmsg_flags| allows to control the flags
// of the recvmsg(2) call.
static ssize_t SendRecvMsgWithFlags(int fd,
uint8_t* reply,
unsigned reply_len,
int recvmsg_flags,
int* result_fd,
const Pickle& request);
private:
// Similar to RecvMsg, but allows to specify |flags| for recvmsg(2).
static ssize_t RecvMsgWithFlags(int fd,
void* msg,
size_t length,
int flags,
std::vector<int>* fds);
};
#endif // BASE_POSIX_UNIX_DOMAIN_SOCKET_LINUX_H_
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