| /* |
| * Copyright (C) 2012-2013 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 <dirent.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <sched.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/capability.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include <linux/prctl.h> |
| |
| #include <cutils/properties.h> |
| |
| #include "private/android_filesystem_config.h" |
| #include "CommandListener.h" |
| #include "LogBuffer.h" |
| #include "LogListener.h" |
| |
| static int drop_privs() { |
| struct sched_param param; |
| memset(¶m, 0, sizeof(param)); |
| |
| if (sched_setscheduler((pid_t) 0, SCHED_BATCH, ¶m) < 0) { |
| return -1; |
| } |
| |
| if (prctl(PR_SET_KEEPCAPS, 1) < 0) { |
| return -1; |
| } |
| |
| if (setgid(AID_LOGD) != 0) { |
| return -1; |
| } |
| |
| if (setuid(AID_LOGD) != 0) { |
| return -1; |
| } |
| |
| struct __user_cap_header_struct capheader; |
| struct __user_cap_data_struct capdata[2]; |
| memset(&capheader, 0, sizeof(capheader)); |
| memset(&capdata, 0, sizeof(capdata)); |
| capheader.version = _LINUX_CAPABILITY_VERSION_3; |
| capheader.pid = 0; |
| |
| capdata[CAP_TO_INDEX(CAP_SYSLOG)].permitted = CAP_TO_MASK(CAP_SYSLOG); |
| capdata[CAP_TO_INDEX(CAP_SYSLOG)].effective = CAP_TO_MASK(CAP_SYSLOG); |
| capdata[0].inheritable = 0; |
| capdata[1].inheritable = 0; |
| |
| if (capset(&capheader, &capdata[0]) < 0) { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| // Foreground waits for exit of the three main persistent threads that |
| // are started here. The three threads are created to manage UNIX |
| // domain client sockets for writing, reading and controlling the user |
| // space logger. Additional transitory per-client threads are created |
| // for each reader once they register. |
| int main() { |
| if (drop_privs() != 0) { |
| return -1; |
| } |
| |
| // Serves the purpose of managing the last logs times read on a |
| // socket connection, and as a reader lock on a range of log |
| // entries. |
| |
| LastLogTimes *times = new LastLogTimes(); |
| |
| // LogBuffer is the object which is responsible for holding all |
| // log entries. |
| |
| LogBuffer *logBuf = new LogBuffer(times); |
| |
| char dgram_qlen_statistics[PROPERTY_VALUE_MAX]; |
| property_get("logd.dgram_qlen.statistics", dgram_qlen_statistics, ""); |
| if (atol(dgram_qlen_statistics)) { |
| logBuf->enableDgramQlenStatistics(); |
| } |
| |
| // LogReader listens on /dev/socket/logdr. When a client |
| // connects, log entries in the LogBuffer are written to the client. |
| |
| LogReader *reader = new LogReader(logBuf); |
| if (reader->startListener()) { |
| exit(1); |
| } |
| |
| // LogListener listens on /dev/socket/logdw for client |
| // initiated log messages. New log entries are added to LogBuffer |
| // and LogReader is notified to send updates to connected clients. |
| |
| LogListener *swl = new LogListener(logBuf, reader); |
| // Backlog and /proc/sys/net/unix/max_dgram_qlen set to large value |
| if (swl->startListener(300)) { |
| exit(1); |
| } |
| |
| // Command listener listens on /dev/socket/logd for incoming logd |
| // administrative commands. |
| |
| CommandListener *cl = new CommandListener(logBuf, reader, swl); |
| if (cl->startListener()) { |
| exit(1); |
| } |
| |
| pause(); |
| exit(0); |
| } |
| |