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/*
* Copyright 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.
*/
#include "util.h"
#include <sys/socket.h>
#include <utility>
#include <android-base/unique_fd.h>
#include <cutils/sockets.h>
#include "protocol.h"
using android::base::unique_fd;
ssize_t send_fd(int sockfd, const void* data, size_t len, unique_fd fd) {
char cmsg_buf[CMSG_SPACE(sizeof(int))];
iovec iov = { .iov_base = const_cast<void*>(data), .iov_len = len };
msghdr msg = {
.msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf, .msg_controllen = sizeof(cmsg_buf),
};
auto cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
*reinterpret_cast<int*>(CMSG_DATA(cmsg)) = fd.get();
return TEMP_FAILURE_RETRY(sendmsg(sockfd, &msg, 0));
}
ssize_t recv_fd(int sockfd, void* _Nonnull data, size_t len, unique_fd* _Nullable out_fd) {
char cmsg_buf[CMSG_SPACE(sizeof(int))];
iovec iov = { .iov_base = const_cast<void*>(data), .iov_len = len };
msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = cmsg_buf,
.msg_controllen = sizeof(cmsg_buf),
.msg_flags = 0,
};
auto cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
ssize_t result = TEMP_FAILURE_RETRY(recvmsg(sockfd, &msg, 0));
if (result == -1) {
return -1;
}
unique_fd fd;
bool received_fd = msg.msg_controllen == sizeof(cmsg_buf);
if (received_fd) {
fd.reset(*reinterpret_cast<int*>(CMSG_DATA(cmsg)));
}
if ((msg.msg_flags & MSG_TRUNC) != 0) {
errno = EFBIG;
return -1;
} else if ((msg.msg_flags & MSG_CTRUNC) != 0) {
errno = ERANGE;
return -1;
}
if (out_fd) {
*out_fd = std::move(fd);
} else if (received_fd) {
errno = ERANGE;
return -1;
}
return result;
}
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