Allow StatsLog to directly write to statsd's socket.
+ Reuse the log_event_list from liblog. StatsLog's binary format remains unchanged
+ Copied socket write code from liblog, including the retry logic.
+ Added build flags to control the StatsLog channel (logd, statsd, or both for debugging)
Bug: 78239479
Test: locally tested and saw logs being written to statsd
Change-Id: I7b1f0069ead00bbf3c29e4bd5b7f363a7ce26abe
diff --git a/stats/stats_log_api_gen/Android.bp b/stats/stats_log_api_gen/Android.bp
index 17819db..73b715a 100644
--- a/stats/stats_log_api_gen/Android.bp
+++ b/stats/stats_log_api_gen/Android.bp
@@ -98,9 +98,16 @@
name: "libstatslog",
generated_sources: ["statslog.cpp"],
generated_headers: ["statslog.h"],
+ srcs: [
+ "stats_event_list.cpp",
+ "statsd_writer.cpp",
+ ],
cflags: [
"-Wall",
"-Werror",
+ "-DLIBLOG_LOG_TAG=1006",
+ "-DWRITE_TO_STATSD=1",
+ "-DWRITE_TO_LOGD=0",
],
export_generated_headers: ["statslog.h"],
shared_libs: [
diff --git a/stats/stats_log_api_gen/main.cpp b/stats/stats_log_api_gen/main.cpp
index 4146e02..638549d 100644
--- a/stats/stats_log_api_gen/main.cpp
+++ b/stats/stats_log_api_gen/main.cpp
@@ -104,7 +104,7 @@
fprintf(out, "#include <mutex>\n");
fprintf(out, "#include <chrono>\n");
fprintf(out, "#include <thread>\n");
- fprintf(out, "#include <log/log_event_list.h>\n");
+ fprintf(out, "#include <stats_event_list.h>\n");
fprintf(out, "#include <log/log.h>\n");
fprintf(out, "#include <statslog.h>\n");
fprintf(out, "#include <utils/SystemClock.h>\n");
@@ -242,7 +242,7 @@
fprintf(out, "{\n");
argIndex = 1;
- fprintf(out, " android_log_event_list event(kStatsEventTag);\n");
+ fprintf(out, " stats_event_list event(kStatsEventTag);\n");
fprintf(out, " event << android::elapsedRealtimeNano();\n\n");
fprintf(out, " event << code;\n\n");
for (vector<java_type_t>::const_iterator arg = signature->begin();
@@ -375,7 +375,7 @@
fprintf(out, "{\n");
argIndex = 1;
- fprintf(out, " android_log_event_list event(kStatsEventTag);\n");
+ fprintf(out, " stats_event_list event(kStatsEventTag);\n");
fprintf(out, " event << android::elapsedRealtimeNano();\n\n");
fprintf(out, " event << code;\n\n");
for (vector<java_type_t>::const_iterator arg = signature->begin();
diff --git a/stats/stats_log_api_gen/stats_event_list.cpp b/stats/stats_log_api_gen/stats_event_list.cpp
new file mode 100644
index 0000000..d456ef0
--- /dev/null
+++ b/stats/stats_log_api_gen/stats_event_list.cpp
@@ -0,0 +1,165 @@
+/*
+ * 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 "stats_event_list.h"
+
+#include "statsd_writer.h"
+
+namespace android {
+namespace util {
+
+enum ReadWriteFlag {
+ kAndroidLoggerRead = 1,
+ kAndroidLoggerWrite = 2,
+};
+
+typedef struct {
+ uint32_t tag;
+ unsigned pos; /* Read/write position into buffer */
+ unsigned count[ANDROID_MAX_LIST_NEST_DEPTH + 1]; /* Number of elements */
+ unsigned list[ANDROID_MAX_LIST_NEST_DEPTH + 1]; /* pos for list counter */
+ unsigned list_nest_depth;
+ unsigned len; /* Length or raw buffer. */
+ bool overflow;
+ bool list_stop; /* next call decrement list_nest_depth and issue a stop */
+ ReadWriteFlag read_write_flag;
+ uint8_t storage[LOGGER_ENTRY_MAX_PAYLOAD];
+} android_log_context_internal;
+
+extern struct android_log_transport_write statsdLoggerWrite;
+
+static int __write_to_statsd_init(struct iovec* vec, size_t nr);
+static int (*write_to_statsd)(struct iovec* vec,
+ size_t nr) = __write_to_statsd_init;
+
+int stats_write_list(android_log_context ctx) {
+ android_log_context_internal* context;
+ const char* msg;
+ ssize_t len;
+
+ context = (android_log_context_internal*)(ctx);
+ if (!context || (kAndroidLoggerWrite != context->read_write_flag)) {
+ return -EBADF;
+ }
+
+ if (context->list_nest_depth) {
+ return -EIO;
+ }
+
+ /* NB: if there was overflow, then log is truncated. Nothing reported */
+ context->storage[1] = context->count[0];
+ len = context->len = context->pos;
+ msg = (const char*)context->storage;
+ /* it's not a list */
+ if (context->count[0] <= 1) {
+ len -= sizeof(uint8_t) + sizeof(uint8_t);
+ if (len < 0) {
+ len = 0;
+ }
+ msg += sizeof(uint8_t) + sizeof(uint8_t);
+ }
+
+ struct iovec vec[2];
+ vec[0].iov_base = &context->tag;
+ vec[0].iov_len = sizeof(context->tag);
+ vec[1].iov_base = (void*)msg;
+ vec[1].iov_len = len;
+ return write_to_statsd(vec, 2);
+}
+
+int stats_event_list::write_to_logger(android_log_context ctx, log_id_t id) {
+ int retValue = 0;
+
+ if (WRITE_TO_LOGD) {
+ retValue = android_log_write_list(ctx, id);
+ }
+
+ if (WRITE_TO_STATSD) {
+ // log_event_list's cast operator is overloaded.
+ int ret = stats_write_list(static_cast<android_log_context>(*this));
+ // In debugging phase, we may write to both logd and statsd. Prefer to return
+ // statsd socket write error code here.
+ if (ret < 0) {
+ retValue = ret;
+ }
+ }
+
+ return retValue;
+}
+
+/* log_init_lock assumed */
+static int __write_to_statsd_initialize_locked() {
+ if (!statsdLoggerWrite.open || ((*statsdLoggerWrite.open)() < 0)) {
+ if (statsdLoggerWrite.close) {
+ (*statsdLoggerWrite.close)();
+ return -ENODEV;
+ }
+ }
+ return 1;
+}
+
+static int __write_to_stats_daemon(struct iovec* vec, size_t nr) {
+ int ret, save_errno;
+ struct timespec ts;
+ size_t len, i;
+
+ for (len = i = 0; i < nr; ++i) {
+ len += vec[i].iov_len;
+ }
+ if (!len) {
+ return -EINVAL;
+ }
+
+ save_errno = errno;
+ clock_gettime(CLOCK_REALTIME, &ts);
+
+ ret = 0;
+
+ ssize_t retval;
+ retval = (*statsdLoggerWrite.write)(&ts, vec, nr);
+ if (ret >= 0) {
+ ret = retval;
+ }
+
+ errno = save_errno;
+ return ret;
+}
+
+static int __write_to_statsd_init(struct iovec* vec, size_t nr) {
+ int ret, save_errno = errno;
+
+ statsd_writer_init_lock();
+
+ if (write_to_statsd == __write_to_statsd_init) {
+ ret = __write_to_statsd_initialize_locked();
+ if (ret < 0) {
+ statsd_writer_init_unlock();
+ errno = save_errno;
+ return ret;
+ }
+
+ write_to_statsd = __write_to_stats_daemon;
+ }
+
+ statsd_writer_init_unlock();
+
+ ret = write_to_statsd(vec, nr);
+ errno = save_errno;
+ return ret;
+}
+
+} // namespace util
+} // namespace android
\ No newline at end of file
diff --git a/stats/stats_log_api_gen/stats_event_list.h b/stats/stats_log_api_gen/stats_event_list.h
new file mode 100644
index 0000000..66b9918
--- /dev/null
+++ b/stats/stats_log_api_gen/stats_event_list.h
@@ -0,0 +1,219 @@
+/*
+ * 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.
+ */
+
+#ifndef ANDROID_STATS_LOG_STATS_EVENT_LIST_H
+#define ANDROID_STATS_LOG_STATS_EVENT_LIST_H
+
+#include <log/log_event_list.h>
+
+namespace android {
+namespace util {
+
+/**
+ * A copy of android_log_event_list class.
+ *
+ * android_log_event_list is going to be deprecated soon, so copy it here to avoid creating
+ * dependency on upstream code. TODO(b/78304629): Rewrite this code.
+ */
+class stats_event_list {
+private:
+ android_log_context ctx;
+ int ret;
+
+ stats_event_list(const stats_event_list&) = delete;
+ void operator=(const stats_event_list&) = delete;
+
+ int write_to_logger(android_log_context context, log_id_t id);
+
+public:
+ explicit stats_event_list(int tag) : ret(0) {
+ ctx = create_android_logger(static_cast<uint32_t>(tag));
+ }
+ explicit stats_event_list(log_msg& log_msg) : ret(0) {
+ ctx = create_android_log_parser(log_msg.msg() + sizeof(uint32_t),
+ log_msg.entry.len - sizeof(uint32_t));
+ }
+ ~stats_event_list() {
+ android_log_destroy(&ctx);
+ }
+
+ int close() {
+ int retval = android_log_destroy(&ctx);
+ if (retval < 0) ret = retval;
+ return retval;
+ }
+
+ /* To allow above C calls to use this class as parameter */
+ operator android_log_context() const {
+ return ctx;
+ }
+
+ /* return errors or transmit status */
+ int status() const {
+ return ret;
+ }
+
+ int begin() {
+ int retval = android_log_write_list_begin(ctx);
+ if (retval < 0) ret = retval;
+ return ret;
+ }
+ int end() {
+ int retval = android_log_write_list_end(ctx);
+ if (retval < 0) ret = retval;
+ return ret;
+ }
+
+ stats_event_list& operator<<(int32_t value) {
+ int retval = android_log_write_int32(ctx, value);
+ if (retval < 0) ret = retval;
+ return *this;
+ }
+
+ stats_event_list& operator<<(uint32_t value) {
+ int retval = android_log_write_int32(ctx, static_cast<int32_t>(value));
+ if (retval < 0) ret = retval;
+ return *this;
+ }
+
+ stats_event_list& operator<<(bool value) {
+ int retval = android_log_write_int32(ctx, value ? 1 : 0);
+ if (retval < 0) ret = retval;
+ return *this;
+ }
+
+ stats_event_list& operator<<(int64_t value) {
+ int retval = android_log_write_int64(ctx, value);
+ if (retval < 0) ret = retval;
+ return *this;
+ }
+
+ stats_event_list& operator<<(uint64_t value) {
+ int retval = android_log_write_int64(ctx, static_cast<int64_t>(value));
+ if (retval < 0) ret = retval;
+ return *this;
+ }
+
+ stats_event_list& operator<<(const char* value) {
+ int retval = android_log_write_string8(ctx, value);
+ if (retval < 0) ret = retval;
+ return *this;
+ }
+
+#if defined(_USING_LIBCXX)
+ stats_event_list& operator<<(const std::string& value) {
+ int retval = android_log_write_string8_len(ctx, value.data(), value.length());
+ if (retval < 0) ret = retval;
+ return *this;
+ }
+#endif
+
+ stats_event_list& operator<<(float value) {
+ int retval = android_log_write_float32(ctx, value);
+ if (retval < 0) ret = retval;
+ return *this;
+ }
+
+ int write(log_id_t id = LOG_ID_EVENTS) {
+ /* facilitate -EBUSY retry */
+ if ((ret == -EBUSY) || (ret > 0)) ret = 0;
+ int retval = write_to_logger(ctx, id);
+ /* existing errors trump transmission errors */
+ if (!ret) ret = retval;
+ return ret;
+ }
+
+ int operator<<(log_id_t id) {
+ write(id);
+ android_log_destroy(&ctx);
+ return ret;
+ }
+
+ /*
+ * Append<Type> methods removes any integer promotion
+ * confusion, and adds access to string with length.
+ * Append methods are also added for all types for
+ * convenience.
+ */
+
+ bool AppendInt(int32_t value) {
+ int retval = android_log_write_int32(ctx, value);
+ if (retval < 0) ret = retval;
+ return ret >= 0;
+ }
+
+ bool AppendLong(int64_t value) {
+ int retval = android_log_write_int64(ctx, value);
+ if (retval < 0) ret = retval;
+ return ret >= 0;
+ }
+
+ bool AppendString(const char* value) {
+ int retval = android_log_write_string8(ctx, value);
+ if (retval < 0) ret = retval;
+ return ret >= 0;
+ }
+
+ bool AppendString(const char* value, size_t len) {
+ int retval = android_log_write_string8_len(ctx, value, len);
+ if (retval < 0) ret = retval;
+ return ret >= 0;
+ }
+
+#if defined(_USING_LIBCXX)
+ bool AppendString(const std::string& value) {
+ int retval = android_log_write_string8_len(ctx, value.data(), value.length());
+ if (retval < 0) ret = retval;
+ return ret;
+ }
+
+ bool Append(const std::string& value) {
+ int retval = android_log_write_string8_len(ctx, value.data(), value.length());
+ if (retval < 0) ret = retval;
+ return ret;
+ }
+#endif
+
+ bool AppendFloat(float value) {
+ int retval = android_log_write_float32(ctx, value);
+ if (retval < 0) ret = retval;
+ return ret >= 0;
+ }
+
+ template <typename Tvalue>
+ bool Append(Tvalue value) {
+ *this << value;
+ return ret >= 0;
+ }
+
+ bool Append(const char* value, size_t len) {
+ int retval = android_log_write_string8_len(ctx, value, len);
+ if (retval < 0) ret = retval;
+ return ret >= 0;
+ }
+
+ android_log_list_element read() {
+ return android_log_read_next(ctx);
+ }
+ android_log_list_element peek() {
+ return android_log_peek_next(ctx);
+ }
+};
+
+} // namespace util
+} // namespace android
+
+#endif // ANDROID_STATS_LOG_STATS_EVENT_LIST_H
diff --git a/stats/stats_log_api_gen/statsd_writer.cpp b/stats/stats_log_api_gen/statsd_writer.cpp
new file mode 100644
index 0000000..d736f7e
--- /dev/null
+++ b/stats/stats_log_api_gen/statsd_writer.cpp
@@ -0,0 +1,272 @@
+/*
+ * 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))))
+
+namespace android {
+namespace util {
+
+static pthread_mutex_t log_init_lock = PTHREAD_MUTEX_INITIALIZER;
+
+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);
+
+struct android_log_transport_write statsdLoggerWrite = {
+ .name = "statsd",
+ .available = statsdAvailable,
+ .open = statsdOpen,
+ .close = statsdClose,
+ .write = statsdWrite,
+};
+
+std::atomic_int android_log_transport_write::sock(-EBADF);
+
+/* 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 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;
+ static atomic_int dropped;
+
+ 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);
+ } else if (ret == -EAGAIN) {
+ atomic_fetch_add_explicit(&dropped, 1, memory_order_relaxed);
+ }
+
+ return ret;
+}
+
+} // namespace util
+} // namespace android
\ No newline at end of file
diff --git a/stats/stats_log_api_gen/statsd_writer.h b/stats/stats_log_api_gen/statsd_writer.h
new file mode 100644
index 0000000..05ebc6c
--- /dev/null
+++ b/stats/stats_log_api_gen/statsd_writer.h
@@ -0,0 +1,49 @@
+/*
+ * 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.
+ */
+
+#ifndef ANDROID_STATS_LOG_STATS_WRITER_H
+#define ANDROID_STATS_LOG_STATS_WRITER_H
+
+#include <pthread.h>
+#include <stdatomic.h>
+#include <sys/socket.h>
+
+namespace android {
+namespace util {
+
+/**
+ * Internal lock should not be exposed. This is bad design.
+ * TODO: rewrite it in c++ code and encapsulate the functionality in a
+ * StatsdWriter class.
+ */
+void statsd_writer_init_lock();
+int statsd_writer_init_trylock();
+void statsd_writer_init_unlock();
+
+struct android_log_transport_write {
+ const char* name; /* human name to describe the transport */
+ static std::atomic_int sock;
+ int (*available)(); /* Does not cause resources to be taken */
+ int (*open)(); /* can be called multiple times, reusing current resources */
+ void (*close)(); /* free up resources */
+ /* write log to transport, returns number of bytes propagated, or -errno */
+ int (*write)(struct timespec* ts, struct iovec* vec, size_t nr);
+};
+
+} // namespace util
+} // namespace android
+
+#endif // ANDROID_STATS_LOG_STATS_WRITER_H
