init/cutils: move kernel logging interface to libcutils from init

Change-Id: Ia0f91b1fcd6cae69d76bf3dd841340958db938a8
Signed-off-by: Dima Zavin <dima@android.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/libcutils/klog.c b/libcutils/klog.c
new file mode 100644
index 000000000..b586a575b
--- /dev/null
+++ b/libcutils/klog.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2008 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 <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <cutils/klog.h>
+
+static int klog_fd = -1;
+static int klog_level = KLOG_DEFAULT_LEVEL;
+
+void klog_set_level(int level) {
+    klog_level = level;
+}
+
+void klog_init(void)
+{
+    static const char *name = "/dev/__kmsg__";
+    if (mknod(name, S_IFCHR | 0600, (1 << 8) | 11) == 0) {
+        klog_fd = open(name, O_WRONLY);
+        fcntl(klog_fd, F_SETFD, FD_CLOEXEC);
+        unlink(name);
+    }
+}
+
+#define LOG_BUF_MAX 512
+
+void klog_write(int level, const char *fmt, ...)
+{
+    char buf[LOG_BUF_MAX];
+    va_list ap;
+
+    if (level > klog_level) return;
+    if (klog_fd < 0) return;
+
+    va_start(ap, fmt);
+    vsnprintf(buf, LOG_BUF_MAX, fmt, ap);
+    buf[LOG_BUF_MAX - 1] = 0;
+    va_end(ap);
+    write(klog_fd, buf, strlen(buf));
+}