1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <errno.h> 18 #include <string.h> 19 20 #include "LeakPipe.h" 21 22 #include "log.h" 23 24 namespace android { 25 26 bool LeakPipe::SendFd(int sock, int fd) { 27 struct msghdr hdr {}; 28 struct iovec iov {}; 29 unsigned int data = 0xfdfdfdfd; 30 alignas(struct cmsghdr) char cmsgbuf[CMSG_SPACE(sizeof(int))]; 31 32 hdr.msg_iov = &iov; 33 hdr.msg_iovlen = 1; 34 iov.iov_base = &data; 35 iov.iov_len = sizeof(data); 36 37 hdr.msg_control = cmsgbuf; 38 hdr.msg_controllen = CMSG_LEN(sizeof(int)); 39 40 struct cmsghdr* cmsg = CMSG_FIRSTHDR(&hdr); 41 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 42 cmsg->cmsg_level = SOL_SOCKET; 43 cmsg->cmsg_type = SCM_RIGHTS; 44 45 *(int*)CMSG_DATA(cmsg) = fd; 46 47 int ret = sendmsg(sock, &hdr, 0); 48 if (ret < 0) { 49 MEM_ALOGE("failed to send fd: %s", strerror(errno)); 50 return false; 51 } 52 if (ret == 0) { 53 MEM_ALOGE("eof when sending fd"); 54 return false; 55 } 56 57 return true; 58 } 59 60 int LeakPipe::ReceiveFd(int sock) { 61 struct msghdr hdr {}; 62 struct iovec iov {}; 63 unsigned int data; 64 alignas(struct cmsghdr) char cmsgbuf[CMSG_SPACE(sizeof(int))]; 65 66 hdr.msg_iov = &iov; 67 hdr.msg_iovlen = 1; 68 iov.iov_base = &data; 69 iov.iov_len = sizeof(data); 70 71 hdr.msg_control = cmsgbuf; 72 hdr.msg_controllen = CMSG_LEN(sizeof(int)); 73 74 int ret = recvmsg(sock, &hdr, 0); 75 if (ret < 0) { 76 MEM_ALOGE("failed to receive fd: %s", strerror(errno)); 77 return -1; 78 } 79 if (ret == 0) { 80 MEM_ALOGE("eof when receiving fd"); 81 return -1; 82 } 83 84 struct cmsghdr* cmsg = CMSG_FIRSTHDR(&hdr); 85 if (cmsg == NULL || cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) { 86 MEM_ALOGE("missing fd while receiving fd"); 87 return -1; 88 } 89 90 return *(int*)CMSG_DATA(cmsg); 91 } 92 93 } // namespace android 94
