c5282c2121
This reverts commit b1eb731197.
Test: post-submit failure now passes
Change-Id: Iabbd18ad8403dd30aa07dd73e42fcc5b233b0222
143 lines
4 KiB
C++
143 lines
4 KiB
C++
/*
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* Copyright (C) 2007-2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "logd_writer.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <inttypes.h>
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#include <poll.h>
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#include <stdarg.h>
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#include <stdatomic.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/un.h>
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#include <time.h>
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#include <unistd.h>
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#include <private/android_filesystem_config.h>
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#include <private/android_logger.h>
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#include "logger.h"
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#include "uio.h"
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static atomic_int logd_socket;
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// Note that it is safe to call connect() multiple times on DGRAM Unix domain sockets, so this
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// function is used to reconnect to logd without requiring a new socket.
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static void LogdConnect() {
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sockaddr_un un = {};
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un.sun_family = AF_UNIX;
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strcpy(un.sun_path, "/dev/socket/logdw");
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TEMP_FAILURE_RETRY(connect(logd_socket, reinterpret_cast<sockaddr*>(&un), sizeof(sockaddr_un)));
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}
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// logd_socket should only be opened once. If we see that logd_socket is uninitialized, we create a
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// new socket and attempt to exchange it into the atomic logd_socket. If the compare/exchange was
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// successful, then that will be the socket used for the duration of the program, otherwise a
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// different thread has already opened and written the socket to the atomic, so close the new socket
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// and return.
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static void GetSocket() {
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if (logd_socket != 0) {
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return;
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}
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int new_socket = TEMP_FAILURE_RETRY(socket(PF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0));
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if (new_socket <= 0) {
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return;
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}
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int uninitialized_value = 0;
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if (!logd_socket.compare_exchange_strong(uninitialized_value, new_socket)) {
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close(new_socket);
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return;
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}
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LogdConnect();
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}
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// This is the one exception to the above. Zygote uses this to clean up open FD's after fork() and
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// before specialization. It is single threaded at this point and therefore this function is
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// explicitly not thread safe. It sets logd_socket to 0, so future logs will be safely initialized
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// whenever they happen.
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void LogdClose() {
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if (logd_socket > 0) {
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close(logd_socket);
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}
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logd_socket = 0;
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}
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int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) {
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ssize_t ret;
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static const unsigned headerLength = 1;
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struct iovec newVec[nr + headerLength];
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android_log_header_t header;
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size_t i, payloadSize;
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GetSocket();
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if (logd_socket <= 0) {
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return -EBADF;
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}
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/* logd, after initialization and priv drop */
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if (getuid() == AID_LOGD) {
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/*
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* ignore log messages we send to ourself (logd).
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* Such log messages are often generated by libraries we depend on
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* which use standard Android logging.
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*/
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return 0;
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}
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header.id = logId;
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header.tid = gettid();
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header.realtime.tv_sec = ts->tv_sec;
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header.realtime.tv_nsec = ts->tv_nsec;
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newVec[0].iov_base = (unsigned char*)&header;
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newVec[0].iov_len = sizeof(header);
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for (payloadSize = 0, i = headerLength; i < nr + headerLength; i++) {
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newVec[i].iov_base = vec[i - headerLength].iov_base;
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payloadSize += newVec[i].iov_len = vec[i - headerLength].iov_len;
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if (payloadSize > LOGGER_ENTRY_MAX_PAYLOAD) {
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newVec[i].iov_len -= payloadSize - LOGGER_ENTRY_MAX_PAYLOAD;
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if (newVec[i].iov_len) {
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++i;
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}
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break;
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}
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}
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ret = TEMP_FAILURE_RETRY(writev(logd_socket, newVec, i));
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if (ret < 0) {
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LogdConnect();
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ret = TEMP_FAILURE_RETRY(writev(logd_socket, newVec, i));
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}
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if (ret < 0) {
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ret = -errno;
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}
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return ret;
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}
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