logd: initial checkin.
* Create a new userspace log daemon for handling logging messages.
Original-Change-Id: I75267df16359684490121e6c31cca48614d79856
Signed-off-by: Nick Kralevich <nnk@google.com>
* Merge conflicts
* rename new syslog daemon to logd to prevent confusion with bionic syslog
* replace racy getGroups call with KISS call to client->getGid()
* Timestamps are filed at logging source
* insert entries into list in timestamp order
* Added LogTimeEntry tail filtration handling
* Added region locking around LogWriter list
* separate threads for each writer
* /dev/socket/logd* permissions
Signed-off-by: Mark Salyzyn <salyzyn@google.com>
(cherry picked from commit 3e76e0a49760c4970b7cda6153e51026af98e4f3)
Author: Nick Kralevich <nnk@google.com>
Change-Id: Ice88b1412d8f9daa7f9119b2b5aaf684a5e28098
diff --git a/logd/main.cpp b/logd/main.cpp
new file mode 100644
index 0000000..667e5bb
--- /dev/null
+++ b/logd/main.cpp
@@ -0,0 +1,115 @@
+/*
+ * 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/capability.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <linux/prctl.h>
+
+#include "private/android_filesystem_config.h"
+#include "CommandListener.h"
+#include "LogBuffer.h"
+#include "LogListener.h"
+
+static int drop_privs() {
+ 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);
+
+ // 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);
+ if (swl->startListener()) {
+ 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);
+}
+