| /* |
| * 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 DEBUG false // STOPSHIP if true |
| #include "Log.h" |
| |
| #include <ctype.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 <cutils/sockets.h> |
| #include <private/android_filesystem_config.h> |
| #include <private/android_logger.h> |
| #include <unordered_map> |
| |
| #include "StatsSocketListener.h" |
| #include "guardrail/StatsdStats.h" |
| #include "stats_log_util.h" |
| |
| namespace android { |
| namespace os { |
| namespace statsd { |
| |
| static const int kLogMsgHeaderSize = 28; |
| |
| StatsSocketListener::StatsSocketListener(std::shared_ptr<LogEventQueue> queue) |
| : SocketListener(getLogSocket(), false /*start listen*/), mQueue(queue) { |
| } |
| |
| StatsSocketListener::~StatsSocketListener() { |
| } |
| |
| bool StatsSocketListener::onDataAvailable(SocketClient* cli) { |
| 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_log_id_t + sizeof(uint16_t) + sizeof(log_time) + 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, |
| }; |
| |
| 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; |
| } |
| |
| char* ptr = ((char*)buffer) + sizeof(android_log_header_t); |
| n -= 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 (n == sizeof(android_log_event_long_t)) { |
| android_log_event_long_t* long_event = reinterpret_cast<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, cred->uid); |
| StatsdStats::getInstance().noteLogLost((int32_t)getWallClockSec(), dropped_count, |
| long_event->header.tag, last_atom_tag, cred->uid, |
| cred->pid); |
| return true; |
| } |
| } |
| |
| log_msg msg; |
| |
| msg.entry.len = n; |
| msg.entry.hdr_size = kLogMsgHeaderSize; |
| msg.entry.sec = time(nullptr); |
| msg.entry.pid = cred->pid; |
| msg.entry.uid = cred->uid; |
| |
| memcpy(msg.buf + kLogMsgHeaderSize, ptr, n + 1); |
| |
| int64_t oldestTimestamp; |
| if (!mQueue->push(std::make_unique<LogEvent>(msg), &oldestTimestamp)) { |
| StatsdStats::getInstance().noteEventQueueOverflow(oldestTimestamp); |
| } |
| |
| return true; |
| } |
| |
| 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 |