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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.
*/
#include <errno.h>
#include <string.h>
#include "LeakPipe.h"
#include "log.h"
namespace android {
bool LeakPipe::SendFd(int sock, int fd) {
struct msghdr hdr {};
struct iovec iov {};
unsigned int data = 0xfdfdfdfd;
alignas(struct cmsghdr) char cmsgbuf[CMSG_SPACE(sizeof(int))];
hdr.msg_iov = &iov;
hdr.msg_iovlen = 1;
iov.iov_base = &data;
iov.iov_len = sizeof(data);
hdr.msg_control = cmsgbuf;
hdr.msg_controllen = CMSG_LEN(sizeof(int));
struct cmsghdr* cmsg = CMSG_FIRSTHDR(&hdr);
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
*(int*)CMSG_DATA(cmsg) = fd;
int ret = sendmsg(sock, &hdr, 0);
if (ret < 0) {
MEM_ALOGE("failed to send fd: %s", strerror(errno));
return false;
}
if (ret == 0) {
MEM_ALOGE("eof when sending fd");
return false;
}
return true;
}
int LeakPipe::ReceiveFd(int sock) {
struct msghdr hdr {};
struct iovec iov {};
unsigned int data;
alignas(struct cmsghdr) char cmsgbuf[CMSG_SPACE(sizeof(int))];
hdr.msg_iov = &iov;
hdr.msg_iovlen = 1;
iov.iov_base = &data;
iov.iov_len = sizeof(data);
hdr.msg_control = cmsgbuf;
hdr.msg_controllen = CMSG_LEN(sizeof(int));
int ret = recvmsg(sock, &hdr, 0);
if (ret < 0) {
MEM_ALOGE("failed to receive fd: %s", strerror(errno));
return -1;
}
if (ret == 0) {
MEM_ALOGE("eof when receiving fd");
return -1;
}
struct cmsghdr* cmsg = CMSG_FIRSTHDR(&hdr);
if (cmsg == NULL || cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
MEM_ALOGE("missing fd while receiving fd");
return -1;
}
return *(int*)CMSG_DATA(cmsg);
}
} // namespace android
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