logd: selinux auditd initial commit

Initial commit for an audit daemon that writes kernel audit
messages to the Android logger. The daemon searches dmesg
for all lines that contain "audit" and writes them. Then
receiving the messages from the netlink socket.

It also formats the messages so they are compatable with
ausearch (type=<t> <m> format)

Modified: Mark Salyzyn <salyzyn@google.com>

- do not start auditd
- merge into logd, stripping unnecessary file logging.
- Convert headers and code to support C++
- Fix bugs in libaudit
- squash timestamp (replace with 0.0) due to duplication
- squash pid due to duplication
- squash comm due to duplication

Change-Id: I421bcf33e7e670d596628b1b5c7c25536ce2d3fe
diff --git a/logd/libaudit.h b/logd/libaudit.h
new file mode 100644
index 0000000..cb114f9
--- /dev/null
+++ b/logd/libaudit.h
@@ -0,0 +1,104 @@
+/*
+ * Copyright 2012, Samsung Telecommunications of America
+ * Copyright (C) 2014 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.
+ *
+ * Written by William Roberts <w.roberts@sta.samsung.com>
+ */
+
+#ifndef _LIBAUDIT_H_
+#define _LIBAUDIT_H_
+
+#include <stdint.h>
+#include <sys/cdefs.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include <linux/netlink.h>
+#include <linux/audit.h>
+
+__BEGIN_DECLS
+
+#define MAX_AUDIT_MESSAGE_LENGTH    8970
+
+typedef enum {
+    GET_REPLY_BLOCKING=0,
+    GET_REPLY_NONBLOCKING
+} reply_t;
+
+typedef enum {
+    WAIT_NO,
+    WAIT_YES
+} rep_wait_t;
+
+/* type == AUDIT_SIGNAL_INFO */
+struct audit_sig_info {
+    uid_t uid;
+    pid_t pid;
+    char ctx[0];
+};
+
+struct audit_message {
+    struct nlmsghdr nlh;
+    char   data[MAX_AUDIT_MESSAGE_LENGTH];
+};
+
+/**
+ * Opens a connection to the Audit netlink socket
+ * @return
+ *  A valid fd on success or < 0 on error with errno set.
+ *  Returns the same errors as man 2 socket.
+ */
+extern int  audit_open(void);
+
+/**
+ * Closes the fd returned from audit_open()
+ * @param fd
+ *  The fd to close
+ */
+extern void audit_close(int fd);
+
+/**
+ *
+ * @param fd
+ *  The fd returned by a call to audit_open()
+ * @param rep
+ *  The response struct to store the response in.
+ * @param block
+ *  Whether or not to block on IO
+ * @param peek
+ *  Whether or not we are to remove the message from
+ *  the queue when we do a read on the netlink socket.
+ * @return
+ *  This function returns 0 on success, else -errno.
+ */
+extern int  audit_get_reply(int fd, struct audit_message *rep, reply_t block,
+               int peek);
+
+/**
+ * Sets a pid to recieve audit netlink events from the kernel
+ * @param fd
+ *  The fd returned by a call to audit_open()
+ * @param pid
+ *  The pid whom to set as the reciever of audit messages
+ * @param wmode
+ *  Whether or not to block on the underlying socket io calls.
+ * @return
+ *  This function returns 0 on success, -errno on error.
+ */
+extern int  audit_set_pid(int fd, uint32_t pid, rep_wait_t wmode);
+
+__END_DECLS
+
+#endif