| /* |
| * Copyright (C) 2018, 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 "statsd_writer.h" |
| |
| #include <cutils/sockets.h> |
| #include <endian.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <inttypes.h> |
| #include <poll.h> |
| #include <private/android_filesystem_config.h> |
| #include <private/android_logger.h> |
| #include <stdarg.h> |
| #include <stdatomic.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <sys/un.h> |
| #include <time.h> |
| #include <unistd.h> |
| |
| /* branchless on many architectures. */ |
| #define min(x, y) ((y) ^ (((x) ^ (y)) & -((x) < (y)))) |
| |
| static pthread_mutex_t log_init_lock = PTHREAD_MUTEX_INITIALIZER; |
| static atomic_int dropped = 0; |
| |
| void statsd_writer_init_lock() { |
| /* |
| * If we trigger a signal handler in the middle of locked activity and the |
| * signal handler logs a message, we could get into a deadlock state. |
| */ |
| pthread_mutex_lock(&log_init_lock); |
| } |
| |
| int statd_writer_trylock() { |
| return pthread_mutex_trylock(&log_init_lock); |
| } |
| |
| void statsd_writer_init_unlock() { |
| pthread_mutex_unlock(&log_init_lock); |
| } |
| |
| static int statsdAvailable(); |
| static int statsdOpen(); |
| static void statsdClose(); |
| static int statsdWrite(struct timespec* ts, struct iovec* vec, size_t nr); |
| static void statsdNoteDrop(); |
| |
| struct android_log_transport_write statsdLoggerWrite = { |
| .name = "statsd", |
| .sock = -EBADF, |
| .available = statsdAvailable, |
| .open = statsdOpen, |
| .close = statsdClose, |
| .write = statsdWrite, |
| .noteDrop = statsdNoteDrop, |
| }; |
| |
| /* log_init_lock assumed */ |
| static int statsdOpen() { |
| int i, ret = 0; |
| |
| i = atomic_load(&statsdLoggerWrite.sock); |
| if (i < 0) { |
| int sock = TEMP_FAILURE_RETRY(socket(PF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0)); |
| if (sock < 0) { |
| ret = -errno; |
| } else { |
| struct sockaddr_un un; |
| memset(&un, 0, sizeof(struct sockaddr_un)); |
| un.sun_family = AF_UNIX; |
| strcpy(un.sun_path, "/dev/socket/statsdw"); |
| |
| if (TEMP_FAILURE_RETRY( |
| connect(sock, (struct sockaddr*)&un, sizeof(struct sockaddr_un))) < 0) { |
| ret = -errno; |
| switch (ret) { |
| case -ENOTCONN: |
| case -ECONNREFUSED: |
| case -ENOENT: |
| i = atomic_exchange(&statsdLoggerWrite.sock, ret); |
| /* FALLTHRU */ |
| default: |
| break; |
| } |
| close(sock); |
| } else { |
| ret = atomic_exchange(&statsdLoggerWrite.sock, sock); |
| if ((ret >= 0) && (ret != sock)) { |
| close(ret); |
| } |
| ret = 0; |
| } |
| } |
| } |
| |
| return ret; |
| } |
| |
| static void __statsdClose(int negative_errno) { |
| int sock = atomic_exchange(&statsdLoggerWrite.sock, negative_errno); |
| if (sock >= 0) { |
| close(sock); |
| } |
| } |
| |
| static void statsdClose() { |
| __statsdClose(-EBADF); |
| } |
| |
| static int statsdAvailable() { |
| if (atomic_load(&statsdLoggerWrite.sock) < 0) { |
| if (access("/dev/socket/statsdw", W_OK) == 0) { |
| return 0; |
| } |
| return -EBADF; |
| } |
| return 1; |
| } |
| |
| static void statsdNoteDrop() { |
| atomic_fetch_add_explicit(&dropped, 1, memory_order_relaxed); |
| } |
| |
| static int statsdWrite(struct timespec* ts, struct iovec* vec, size_t nr) { |
| ssize_t ret; |
| int sock; |
| static const unsigned headerLength = 1; |
| struct iovec newVec[nr + headerLength]; |
| android_log_header_t header; |
| size_t i, payloadSize; |
| |
| sock = atomic_load(&statsdLoggerWrite.sock); |
| if (sock < 0) switch (sock) { |
| case -ENOTCONN: |
| case -ECONNREFUSED: |
| case -ENOENT: |
| break; |
| default: |
| return -EBADF; |
| } |
| /* |
| * struct { |
| * // what we provide to socket |
| * android_log_header_t header; |
| * // caller provides |
| * union { |
| * struct { |
| * char prio; |
| * char payload[]; |
| * } string; |
| * struct { |
| * uint32_t tag |
| * char payload[]; |
| * } binary; |
| * }; |
| * }; |
| */ |
| |
| header.tid = gettid(); |
| header.realtime.tv_sec = ts->tv_sec; |
| header.realtime.tv_nsec = ts->tv_nsec; |
| |
| newVec[0].iov_base = (unsigned char*)&header; |
| newVec[0].iov_len = sizeof(header); |
| |
| // If we dropped events before, try to tell statsd. |
| if (sock >= 0) { |
| int32_t snapshot = atomic_exchange_explicit(&dropped, 0, memory_order_relaxed); |
| if (snapshot) { |
| android_log_event_int_t buffer; |
| header.id = LOG_ID_STATS; |
| buffer.header.tag = htole32(LIBLOG_LOG_TAG); |
| buffer.payload.type = EVENT_TYPE_INT; |
| buffer.payload.data = htole32(snapshot); |
| |
| newVec[headerLength].iov_base = &buffer; |
| newVec[headerLength].iov_len = sizeof(buffer); |
| |
| ret = TEMP_FAILURE_RETRY(writev(sock, newVec, 2)); |
| if (ret != (ssize_t)(sizeof(header) + sizeof(buffer))) { |
| atomic_fetch_add_explicit(&dropped, snapshot, memory_order_relaxed); |
| } |
| } |
| } |
| |
| header.id = LOG_ID_STATS; |
| |
| for (payloadSize = 0, i = headerLength; i < nr + headerLength; i++) { |
| newVec[i].iov_base = vec[i - headerLength].iov_base; |
| payloadSize += newVec[i].iov_len = vec[i - headerLength].iov_len; |
| |
| if (payloadSize > LOGGER_ENTRY_MAX_PAYLOAD) { |
| newVec[i].iov_len -= payloadSize - LOGGER_ENTRY_MAX_PAYLOAD; |
| if (newVec[i].iov_len) { |
| ++i; |
| } |
| break; |
| } |
| } |
| |
| /* |
| * The write below could be lost, but will never block. |
| * |
| * ENOTCONN occurs if statsd has died. |
| * ENOENT occurs if statsd is not running and socket is missing. |
| * ECONNREFUSED occurs if we can not reconnect to statsd. |
| * EAGAIN occurs if statsd is overloaded. |
| */ |
| if (sock < 0) { |
| ret = sock; |
| } else { |
| ret = TEMP_FAILURE_RETRY(writev(sock, newVec, i)); |
| if (ret < 0) { |
| ret = -errno; |
| } |
| } |
| switch (ret) { |
| case -ENOTCONN: |
| case -ECONNREFUSED: |
| case -ENOENT: |
| if (statd_writer_trylock()) { |
| return ret; /* in a signal handler? try again when less stressed |
| */ |
| } |
| __statsdClose(ret); |
| ret = statsdOpen(); |
| statsd_writer_init_unlock(); |
| |
| if (ret < 0) { |
| return ret; |
| } |
| |
| ret = TEMP_FAILURE_RETRY(writev(atomic_load(&statsdLoggerWrite.sock), newVec, i)); |
| if (ret < 0) { |
| ret = -errno; |
| } |
| /* FALLTHRU */ |
| default: |
| break; |
| } |
| |
| if (ret > (ssize_t)sizeof(header)) { |
| ret -= sizeof(header); |
| } |
| |
| return ret; |
| } |