Log more timing information from init.

Also make important events in init's life NOTICE rather than INFO,
and ensure that NOTICE events actually make it to the kernel log.

Also fix the logging so that if you have a printf format string
error, the compiler now catches it.

Also give messages from init, ueventd, and watchdogd distinct tags.
(Previously they'd all call themselves "init", and dmesg doesn't
include pids, so you couldn't untangle them.)

Also include the tag in SELinux messages.

Bug: 19544788
Change-Id: Ica6daea065bfdb80155c52c0b06f346a7df208fe
diff --git a/init/log.cpp b/init/log.cpp
new file mode 100644
index 0000000..d32f2da
--- /dev/null
+++ b/init/log.cpp
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2015 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 <stdlib.h>
+#include <string.h>
+#include <sys/uio.h>
+
+#include <selinux/selinux.h>
+
+#include "log.h"
+
+static void init_klog_vwrite(int level, const char* fmt, va_list ap) {
+    static const char* tag = basename(getprogname());
+
+    char prefix[64];
+    snprintf(prefix, sizeof(prefix), "<%d>%s: ", level, tag);
+
+    char msg[512];
+    vsnprintf(msg, sizeof(msg), fmt, ap);
+
+    iovec iov[2];
+    iov[0].iov_base = prefix;
+    iov[0].iov_len = strlen(prefix);
+    iov[1].iov_base = msg;
+    iov[1].iov_len = strlen(msg);
+
+    klog_writev(level, iov, 2);
+}
+
+void init_klog_write(int level, const char* fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    init_klog_vwrite(level, fmt, ap);
+    va_end(ap);
+}
+
+int selinux_klog_callback(int type, const char *fmt, ...) {
+    int level = KLOG_ERROR_LEVEL;
+    if (type == SELINUX_WARNING) {
+        level = KLOG_WARNING_LEVEL;
+    } else if (type == SELINUX_INFO) {
+        level = KLOG_INFO_LEVEL;
+    }
+    va_list ap;
+    va_start(ap, fmt);
+    init_klog_vwrite(level, fmt, ap);
+    va_end(ap);
+    return 0;
+}