1/* 2 * Copyright 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 "debuggerd/util.h" 18 19#include <sys/socket.h> 20 21#include <utility> 22 23#include <android-base/unique_fd.h> 24#include <cutils/sockets.h> 25#include <debuggerd/protocol.h> 26 27#include "private/libc_logging.h" 28 29using android::base::unique_fd; 30 31ssize_t send_fd(int sockfd, const void* data, size_t len, unique_fd fd) { 32 char cmsg_buf[CMSG_SPACE(sizeof(int))]; 33 34 iovec iov = { .iov_base = const_cast<void*>(data), .iov_len = len }; 35 msghdr msg = { 36 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf, .msg_controllen = sizeof(cmsg_buf), 37 }; 38 auto cmsg = CMSG_FIRSTHDR(&msg); 39 cmsg->cmsg_level = SOL_SOCKET; 40 cmsg->cmsg_type = SCM_RIGHTS; 41 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 42 *reinterpret_cast<int*>(CMSG_DATA(cmsg)) = fd.get(); 43 44 return TEMP_FAILURE_RETRY(sendmsg(sockfd, &msg, 0)); 45} 46 47ssize_t recv_fd(int sockfd, void* _Nonnull data, size_t len, unique_fd* _Nullable out_fd) { 48 char cmsg_buf[CMSG_SPACE(sizeof(int))]; 49 50 iovec iov = { .iov_base = const_cast<void*>(data), .iov_len = len }; 51 msghdr msg = { 52 .msg_iov = &iov, 53 .msg_iovlen = 1, 54 .msg_control = cmsg_buf, 55 .msg_controllen = sizeof(cmsg_buf), 56 .msg_flags = 0, 57 }; 58 auto cmsg = CMSG_FIRSTHDR(&msg); 59 cmsg->cmsg_level = SOL_SOCKET; 60 cmsg->cmsg_type = SCM_RIGHTS; 61 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 62 63 ssize_t result = TEMP_FAILURE_RETRY(recvmsg(sockfd, &msg, 0)); 64 if (result == -1) { 65 return -1; 66 } 67 68 unique_fd fd; 69 bool received_fd = msg.msg_controllen == sizeof(cmsg_buf); 70 if (received_fd) { 71 fd.reset(*reinterpret_cast<int*>(CMSG_DATA(cmsg))); 72 } 73 74 if ((msg.msg_flags & MSG_TRUNC) != 0) { 75 errno = EFBIG; 76 return -1; 77 } else if ((msg.msg_flags & MSG_CTRUNC) != 0) { 78 errno = ERANGE; 79 return -1; 80 } 81 82 if (out_fd) { 83 *out_fd = std::move(fd); 84 } else if (received_fd) { 85 errno = ERANGE; 86 return -1; 87 } 88 89 return result; 90} 91 92bool Pipe(unique_fd* read, unique_fd* write) { 93 int pipefds[2]; 94 if (pipe(pipefds) != 0) { 95 return false; 96 } 97 read->reset(pipefds[0]); 98 write->reset(pipefds[1]); 99 return true; 100} 101