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/*
* 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.
*/
#define STATSD_DEBUG false // STOPSHIP if true
#include "Log.h"
#include "StatsSocketListener.h"
#include <ctype.h>
#include <cutils/sockets.h>
#include <limits.h>
#include <stdio.h>
#include <sys/cdefs.h>
#include <sys/prctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include "guardrail/StatsdStats.h"
#include "logd/logevent_util.h"
#include "stats_log_util.h"
#include "statslog_statsd.h"
#include "utils/api_tracing.h"
namespace android {
namespace os {
namespace statsd {
StatsSocketListener::StatsSocketListener(const std::shared_ptr<LogEventQueue>& queue,
const std::shared_ptr<LogEventFilter>& logEventFilter)
: SocketListener(getLogSocket(), false /*start listen*/),
mQueue(queue),
mLogEventFilter(logEventFilter) {
}
bool StatsSocketListener::onDataAvailable(SocketClient* cli) {
ATRACE_CALL();
static bool name_set;
if (!name_set) {
prctl(PR_SET_NAME, "statsd.writer");
name_set = true;
}
// + 1 to ensure null terminator if MAX_PAYLOAD buffer is received
char buffer[sizeof(android_log_header_t) + LOGGER_ENTRY_MAX_PAYLOAD + 1];
struct iovec iov = {buffer, sizeof(buffer) - 1};
alignas(4) char control[CMSG_SPACE(sizeof(struct ucred))];
struct msghdr hdr = {
NULL, 0, &iov, 1, control, sizeof(control), 0,
};
const int socket = cli->getSocket();
// To clear the entire buffer is secure/safe, but this contributes to 1.68%
// overhead under logging load. We are safe because we check counts, but
// still need to clear null terminator
// memset(buffer, 0, sizeof(buffer));
ssize_t n = recvmsg(socket, &hdr, 0);
if (n <= (ssize_t)(sizeof(android_log_header_t))) {
return false;
}
buffer[n] = 0;
struct ucred* cred = NULL;
struct cmsghdr* cmsg = CMSG_FIRSTHDR(&hdr);
while (cmsg != NULL) {
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDENTIALS) {
cred = (struct ucred*)CMSG_DATA(cmsg);
break;
}
cmsg = CMSG_NXTHDR(&hdr, cmsg);
}
struct ucred fake_cred;
if (cred == NULL) {
cred = &fake_cred;
cred->pid = 0;
cred->uid = DEFAULT_OVERFLOWUID;
}
const uint32_t uid = cred->uid;
const uint32_t pid = cred->pid;
processSocketMessage(buffer, n, uid, pid, *mQueue, *mLogEventFilter);
return true;
}
void StatsSocketListener::processSocketMessage(const char* buffer, const uint32_t len, uint32_t uid,
uint32_t pid, LogEventQueue& queue,
const LogEventFilter& filter) {
ATRACE_CALL();
static const uint32_t kStatsEventTag = 1937006964;
if (len <= (ssize_t)(sizeof(android_log_header_t)) + sizeof(uint32_t)) {
return;
}
const uint8_t* ptr = ((uint8_t*)buffer) + sizeof(android_log_header_t);
uint32_t bufferLen = len - sizeof(android_log_header_t);
// When a log failed to write to statsd socket (e.g., due ot EBUSY), a special message would
// be sent to statsd when the socket communication becomes available again.
// The format is android_log_event_int_t with a single integer in the payload indicating the
// number of logs that failed. (*FORMAT MUST BE IN SYNC WITH system/core/libstats*)
// Note that all normal stats logs are in the format of event_list, so there won't be confusion.
//
// TODO(b/80538532): In addition to log it in StatsdStats, we should properly reset the config.
if (bufferLen == sizeof(android_log_event_long_t)) {
const android_log_event_long_t* long_event =
reinterpret_cast<const android_log_event_long_t*>(ptr);
if (long_event->payload.type == EVENT_TYPE_LONG) {
int64_t composed_long = long_event->payload.data;
// format:
// |last_tag|dropped_count|
int32_t dropped_count = (int32_t)(0xffffffff & composed_long);
int32_t last_atom_tag = (int32_t)((0xffffffff00000000 & (uint64_t)composed_long) >> 32);
ALOGE("Found dropped events: %d error %d last atom tag %d from uid %d", dropped_count,
long_event->header.tag, last_atom_tag, uid);
StatsdStats::getInstance().noteLogLost((int32_t)getWallClockSec(), dropped_count,
long_event->header.tag, last_atom_tag, uid, pid);
return;
}
}
// test that received valid StatsEvent buffer
const uint32_t statsEventTag = *reinterpret_cast<const uint32_t*>(ptr);
if (statsEventTag != kStatsEventTag) {
return;
}
// move past the 4-byte StatsEventTag
const uint8_t* msg = ptr + sizeof(uint32_t);
bufferLen -= sizeof(uint32_t);
processStatsEventBuffer(msg, bufferLen, uid, pid, queue, filter);
}
void StatsSocketListener::processStatsEventBuffer(const uint8_t* msg, const uint32_t len,
uint32_t uid, uint32_t pid, LogEventQueue& queue,
const LogEventFilter& filter) {
ATRACE_CALL();
std::unique_ptr<LogEvent> logEvent = std::make_unique<LogEvent>(uid, pid);
if (filter.getFilteringEnabled()) {
const LogEvent::BodyBufferInfo bodyInfo = logEvent->parseHeader(msg, len);
if (filter.isAtomInUse(logEvent->GetTagId())) {
logEvent->parseBody(bodyInfo);
}
} else {
logEvent->parseBuffer(msg, len);
}
const int32_t atomId = logEvent->GetTagId();
const bool isAtomSkipped = logEvent->isParsedHeaderOnly();
const int64_t atomTimestamp = logEvent->GetElapsedTimestampNs();
if (atomId == util::STATS_SOCKET_LOSS_REPORTED) {
if (isAtomSkipped) {
ALOGW("Atom STATS_SOCKET_LOSS_REPORTED should not be skipped");
}
// handling socket loss info reported atom
// processing it here to not lose info due to queue overflow
const std::optional<SocketLossInfo>& lossInfo = toSocketLossInfo(*logEvent);
if (lossInfo) {
StatsdStats::getInstance().noteAtomSocketLoss(*lossInfo);
} else {
ALOGW("Atom STATS_SOCKET_LOSS_REPORTED content is invalid");
}
}
const auto [success, oldestTimestamp, queueSize] = queue.push(std::move(logEvent));
if (success) {
StatsdStats::getInstance().noteEventQueueSize(queueSize, atomTimestamp);
} else {
StatsdStats::getInstance().noteEventQueueOverflow(oldestTimestamp, atomId, isAtomSkipped);
}
}
int StatsSocketListener::getLogSocket() {
static const char socketName[] = "statsdw";
int sock = android_get_control_socket(socketName);
if (sock < 0) { // statsd started up in init.sh
sock = socket_local_server(socketName, ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_DGRAM);
int on = 1;
if (setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) {
return -1;
}
}
return sock;
}
} // namespace statsd
} // namespace os
} // namespace android
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