diff options
Diffstat (limited to 'base/cmsg.cpp')
| -rw-r--r-- | base/cmsg.cpp | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/base/cmsg.cpp b/base/cmsg.cpp deleted file mode 100644 index 1fa873c822..0000000000 --- a/base/cmsg.cpp +++ /dev/null @@ -1,173 +0,0 @@ -/* - * Copyright (C) 2019 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 <android-base/cmsg.h> - -#include <errno.h> -#include <fcntl.h> -#include <stdlib.h> -#include <sys/socket.h> -#include <sys/user.h> - -#include <memory> - -#include <android-base/logging.h> - -namespace android { -namespace base { - -ssize_t SendFileDescriptorVector(borrowed_fd sockfd, const void* data, size_t len, - const std::vector<int>& fds) { - size_t cmsg_space = CMSG_SPACE(sizeof(int) * fds.size()); - size_t cmsg_len = CMSG_LEN(sizeof(int) * fds.size()); - if (cmsg_space >= PAGE_SIZE) { - errno = ENOMEM; - return -1; - } - - alignas(struct cmsghdr) char cmsg_buf[cmsg_space]; - iovec iov = {.iov_base = const_cast<void*>(data), .iov_len = len}; - msghdr msg = { - .msg_name = nullptr, - .msg_namelen = 0, - .msg_iov = &iov, - .msg_iovlen = 1, - .msg_control = cmsg_buf, - // We can't cast to the actual type of the field, because it's different across platforms. - .msg_controllen = static_cast<unsigned int>(cmsg_space), - .msg_flags = 0, - }; - - struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg); - cmsg->cmsg_level = SOL_SOCKET; - cmsg->cmsg_type = SCM_RIGHTS; - cmsg->cmsg_len = cmsg_len; - - int* cmsg_fds = reinterpret_cast<int*>(CMSG_DATA(cmsg)); - for (size_t i = 0; i < fds.size(); ++i) { - cmsg_fds[i] = fds[i]; - } - -#if defined(__linux__) - int flags = MSG_NOSIGNAL; -#else - int flags = 0; -#endif - - return TEMP_FAILURE_RETRY(sendmsg(sockfd.get(), &msg, flags)); -} - -ssize_t ReceiveFileDescriptorVector(borrowed_fd sockfd, void* data, size_t len, size_t max_fds, - std::vector<unique_fd>* fds) { - fds->clear(); - - size_t cmsg_space = CMSG_SPACE(sizeof(int) * max_fds); - if (cmsg_space >= PAGE_SIZE) { - errno = ENOMEM; - return -1; - } - - alignas(struct cmsghdr) char cmsg_buf[cmsg_space]; - iovec iov = {.iov_base = const_cast<void*>(data), .iov_len = len}; - msghdr msg = { - .msg_name = nullptr, - .msg_namelen = 0, - .msg_iov = &iov, - .msg_iovlen = 1, - .msg_control = cmsg_buf, - // We can't cast to the actual type of the field, because it's different across platforms. - .msg_controllen = static_cast<unsigned int>(cmsg_space), - .msg_flags = 0, - }; - - int flags = MSG_TRUNC | MSG_CTRUNC; -#if defined(__linux__) - flags |= MSG_CMSG_CLOEXEC | MSG_NOSIGNAL; -#endif - - ssize_t rc = TEMP_FAILURE_RETRY(recvmsg(sockfd.get(), &msg, flags)); - - if (rc == -1) { - return -1; - } - - int error = 0; - if ((msg.msg_flags & MSG_TRUNC)) { - LOG(ERROR) << "message was truncated when receiving file descriptors"; - error = EMSGSIZE; - } else if ((msg.msg_flags & MSG_CTRUNC)) { - LOG(ERROR) << "control message was truncated when receiving file descriptors"; - error = EMSGSIZE; - } - - std::vector<unique_fd> received_fds; - struct cmsghdr* cmsg; - for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != nullptr; cmsg = CMSG_NXTHDR(&msg, cmsg)) { - if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) { - LOG(ERROR) << "received unexpected cmsg: [" << cmsg->cmsg_level << ", " << cmsg->cmsg_type - << "]"; - error = EBADMSG; - continue; - } - - // There isn't a macro that does the inverse of CMSG_LEN, so hack around it ourselves, with - // some asserts to ensure that CMSG_LEN behaves as we expect. -#if defined(__linux__) -#define CMSG_ASSERT static_assert -#else -// CMSG_LEN is somehow not constexpr on darwin. -#define CMSG_ASSERT CHECK -#endif - CMSG_ASSERT(CMSG_LEN(0) + 1 * sizeof(int) == CMSG_LEN(1 * sizeof(int))); - CMSG_ASSERT(CMSG_LEN(0) + 2 * sizeof(int) == CMSG_LEN(2 * sizeof(int))); - CMSG_ASSERT(CMSG_LEN(0) + 3 * sizeof(int) == CMSG_LEN(3 * sizeof(int))); - CMSG_ASSERT(CMSG_LEN(0) + 4 * sizeof(int) == CMSG_LEN(4 * sizeof(int))); - - if (cmsg->cmsg_len % sizeof(int) != 0) { - LOG(FATAL) << "cmsg_len(" << cmsg->cmsg_len << ") not aligned to sizeof(int)"; - } else if (cmsg->cmsg_len <= CMSG_LEN(0)) { - LOG(FATAL) << "cmsg_len(" << cmsg->cmsg_len << ") not long enough to hold any data"; - } - - int* cmsg_fds = reinterpret_cast<int*>(CMSG_DATA(cmsg)); - size_t cmsg_fdcount = static_cast<size_t>(cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); - for (size_t i = 0; i < cmsg_fdcount; ++i) { -#if !defined(__linux__) - // Linux uses MSG_CMSG_CLOEXEC instead of doing this manually. - fcntl(cmsg_fds[i], F_SETFD, FD_CLOEXEC); -#endif - received_fds.emplace_back(cmsg_fds[i]); - } - } - - if (error != 0) { - errno = error; - return -1; - } - - if (received_fds.size() > max_fds) { - LOG(ERROR) << "received too many file descriptors, expected " << fds->size() << ", received " - << received_fds.size(); - errno = EMSGSIZE; - return -1; - } - - *fds = std::move(received_fds); - return rc; -} - -} // namespace base -} // namespace android |