285 lines
8.4 KiB
C
285 lines
8.4 KiB
C
/*
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* Copyright (C) 2018, 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 "statsd_writer.h"
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#include <cutils/fs.h>
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#include <cutils/sockets.h>
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#include <cutils/threads.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 <private/android_filesystem_config.h>
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#include <private/android_logger.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/stat.h>
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#include <sys/types.h>
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#include <sys/uio.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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static pthread_mutex_t log_init_lock = PTHREAD_MUTEX_INITIALIZER;
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static atomic_int dropped = 0;
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static atomic_int log_error = 0;
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static atomic_int atom_tag = 0;
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void statsd_writer_init_lock() {
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/*
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* If we trigger a signal handler in the middle of locked activity and the
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* signal handler logs a message, we could get into a deadlock state.
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*/
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pthread_mutex_lock(&log_init_lock);
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}
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int statd_writer_trylock() {
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return pthread_mutex_trylock(&log_init_lock);
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}
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void statsd_writer_init_unlock() {
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pthread_mutex_unlock(&log_init_lock);
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}
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static int statsdAvailable();
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static int statsdOpen();
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static void statsdClose();
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static int statsdWrite(struct timespec* ts, struct iovec* vec, size_t nr);
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static void statsdNoteDrop();
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struct android_log_transport_write statsdLoggerWrite = {
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.name = "statsd",
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.sock = -EBADF,
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.available = statsdAvailable,
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.open = statsdOpen,
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.close = statsdClose,
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.write = statsdWrite,
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.noteDrop = statsdNoteDrop,
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};
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/* log_init_lock assumed */
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static int statsdOpen() {
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int i, ret = 0;
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i = atomic_load(&statsdLoggerWrite.sock);
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if (i < 0) {
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int flags = SOCK_DGRAM;
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#ifdef SOCK_CLOEXEC
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flags |= SOCK_CLOEXEC;
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#endif
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#ifdef SOCK_NONBLOCK
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flags |= SOCK_NONBLOCK;
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#endif
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int sock = TEMP_FAILURE_RETRY(socket(PF_UNIX, flags, 0));
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if (sock < 0) {
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ret = -errno;
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} else {
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int sndbuf = 1 * 1024 * 1024; // set max send buffer size 1MB
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socklen_t bufLen = sizeof(sndbuf);
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// SO_RCVBUF does not have an effect on unix domain socket, but SO_SNDBUF does.
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// Proceed to connect even setsockopt fails.
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setsockopt(sock, SOL_SOCKET, SO_SNDBUF, &sndbuf, bufLen);
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struct sockaddr_un un;
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memset(&un, 0, sizeof(struct sockaddr_un));
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un.sun_family = AF_UNIX;
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strcpy(un.sun_path, "/dev/socket/statsdw");
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if (TEMP_FAILURE_RETRY(
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connect(sock, (struct sockaddr*)&un, sizeof(struct sockaddr_un))) < 0) {
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ret = -errno;
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switch (ret) {
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case -ENOTCONN:
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case -ECONNREFUSED:
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case -ENOENT:
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i = atomic_exchange(&statsdLoggerWrite.sock, ret);
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/* FALLTHRU */
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default:
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break;
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}
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close(sock);
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} else {
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ret = atomic_exchange(&statsdLoggerWrite.sock, sock);
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if ((ret >= 0) && (ret != sock)) {
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close(ret);
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}
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ret = 0;
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}
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}
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}
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return ret;
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}
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static void __statsdClose(int negative_errno) {
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int sock = atomic_exchange(&statsdLoggerWrite.sock, negative_errno);
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if (sock >= 0) {
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close(sock);
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}
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}
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static void statsdClose() {
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__statsdClose(-EBADF);
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}
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static int statsdAvailable() {
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if (atomic_load(&statsdLoggerWrite.sock) < 0) {
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if (access("/dev/socket/statsdw", W_OK) == 0) {
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return 0;
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}
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return -EBADF;
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}
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return 1;
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}
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static void statsdNoteDrop(int error, int tag) {
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atomic_fetch_add_explicit(&dropped, 1, memory_order_relaxed);
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atomic_exchange_explicit(&log_error, error, memory_order_relaxed);
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atomic_exchange_explicit(&atom_tag, tag, memory_order_relaxed);
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}
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static int statsdWrite(struct timespec* ts, struct iovec* vec, size_t nr) {
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ssize_t ret;
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int sock;
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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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sock = atomic_load(&statsdLoggerWrite.sock);
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if (sock < 0) switch (sock) {
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case -ENOTCONN:
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case -ECONNREFUSED:
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case -ENOENT:
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break;
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default:
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return -EBADF;
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}
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/*
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* struct {
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* // what we provide to socket
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* android_log_header_t header;
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* // caller provides
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* union {
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* struct {
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* char prio;
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* char payload[];
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* } string;
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* struct {
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* uint32_t tag
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* char payload[];
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* } binary;
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* };
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* };
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*/
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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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// If we dropped events before, try to tell statsd.
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if (sock >= 0) {
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int32_t snapshot = atomic_exchange_explicit(&dropped, 0, memory_order_relaxed);
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if (snapshot) {
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android_log_event_long_t buffer;
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header.id = LOG_ID_STATS;
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// store the last log error in the tag field. This tag field is not used by statsd.
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buffer.header.tag = atomic_load(&log_error);
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buffer.payload.type = EVENT_TYPE_LONG;
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// format:
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// |atom_tag|dropped_count|
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int64_t composed_long = atomic_load(&atom_tag);
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// Send 2 int32's via an int64.
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composed_long = ((composed_long << 32) | ((int64_t)snapshot));
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buffer.payload.data = composed_long;
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newVec[headerLength].iov_base = &buffer;
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newVec[headerLength].iov_len = sizeof(buffer);
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ret = TEMP_FAILURE_RETRY(writev(sock, newVec, 2));
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if (ret != (ssize_t)(sizeof(header) + sizeof(buffer))) {
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atomic_fetch_add_explicit(&dropped, snapshot, memory_order_relaxed);
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}
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}
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}
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header.id = LOG_ID_STATS;
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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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/*
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* The write below could be lost, but will never block.
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*
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* ENOTCONN occurs if statsd has died.
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* ENOENT occurs if statsd is not running and socket is missing.
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* ECONNREFUSED occurs if we can not reconnect to statsd.
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* EAGAIN occurs if statsd is overloaded.
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*/
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if (sock < 0) {
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ret = sock;
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} else {
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ret = TEMP_FAILURE_RETRY(writev(sock, newVec, i));
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if (ret < 0) {
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ret = -errno;
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}
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}
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switch (ret) {
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case -ENOTCONN:
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case -ECONNREFUSED:
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case -ENOENT:
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if (statd_writer_trylock()) {
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return ret; /* in a signal handler? try again when less stressed
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*/
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}
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__statsdClose(ret);
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ret = statsdOpen();
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statsd_writer_init_unlock();
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if (ret < 0) {
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return ret;
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}
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ret = TEMP_FAILURE_RETRY(writev(atomic_load(&statsdLoggerWrite.sock), newVec, i));
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if (ret < 0) {
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ret = -errno;
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}
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/* FALLTHRU */
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default:
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break;
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}
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if (ret > (ssize_t)sizeof(header)) {
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ret -= sizeof(header);
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}
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return ret;
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}
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