Fix early init logging.

Remove the /dev/__kmsg__ workarounds (which can then be removed
from sepolicy), and fix confusion in the translation between
android-base logging and kernel logging priorities (in particular,
where 'notice' comes in the hierarchy).

Bug: http://b/30317429
Change-Id: I6eaf9919904b6b55bc402c20bf1a4ae269014bc7
Test: adb shell dmesg | grep init

init/action.cpp

@@ -118,7 +118,7 @@ void Action::ExecuteCommand(const Command& command) const {
     Timer t;
     int result = command.InvokeFunc();
 
-    if (klog_get_level() >= KLOG_INFO_LEVEL) {
+    if (klog_get_level() >= KLOG_DEBUG_LEVEL) {
         std::string trigger_name = BuildTriggersString();
         std::string cmd_str = command.BuildCommandString();
         std::string source = command.BuildSourceString();

init/init.cpp

@@ -29,6 +29,7 @@
 #include <sys/mount.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
+#include <sys/sysmacros.h>
 #include <sys/types.h>
 #include <sys/un.h>
 #include <sys/wait.h>
@@ -487,12 +488,11 @@ int main(int argc, char** argv) {
         mount("proc", "/proc", "proc", 0, "hidepid=2,gid=" MAKE_STR(AID_READPROC));
         mount("sysfs", "/sys", "sysfs", 0, NULL);
         mount("selinuxfs", "/sys/fs/selinux", "selinuxfs", 0, NULL);
+        mknod("/dev/kmsg", S_IFCHR | 0600, makedev(1, 11));
     }
 
-    // We must have some place other than / to create the device nodes for
-    // kmsg and null, otherwise we won't be able to remount / read-only
-    // later on. Now that tmpfs is mounted on /dev, we can actually talk
-    // to the outside world.
+    // Now that tmpfs is mounted on /dev and we have /dev/kmsg, we can actually
+    // talk to the outside world...
     InitKernelLogging(argv);
 
     LOG(INFO) << "init " << (is_first_stage ? "first stage" : "second stage") << " started!";
@@ -536,6 +536,7 @@ int main(int argc, char** argv) {
     // This must happen before /dev is populated by ueventd.
     LOG(INFO) << "Running restorecon...";
     restorecon("/dev");
+    restorecon("/dev/kmsg");
     restorecon("/dev/socket");
     restorecon("/dev/__properties__");
     restorecon("/property_contexts");

init/log.cpp

@@ -26,8 +26,12 @@
 #include <selinux/selinux.h>
 
 static const int kLogSeverityToKLogLevel[] = {
-    KLOG_NOTICE_LEVEL, KLOG_DEBUG_LEVEL, KLOG_INFO_LEVEL,
-    KLOG_WARNING_LEVEL, KLOG_ERROR_LEVEL, KLOG_ERROR_LEVEL,
+    [android::base::VERBOSE] = KLOG_DEBUG_LEVEL,
+    [android::base::DEBUG] = KLOG_DEBUG_LEVEL,
+    [android::base::INFO] = KLOG_INFO_LEVEL,
+    [android::base::WARNING] = KLOG_WARNING_LEVEL,
+    [android::base::ERROR] = KLOG_ERROR_LEVEL,
+    [android::base::FATAL] = KLOG_ERROR_LEVEL,
 };
 static_assert(arraysize(kLogSeverityToKLogLevel) == android::base::FATAL + 1,
               "Mismatch in size of kLogSeverityToKLogLevel and values in LogSeverity");
@@ -68,7 +72,7 @@ void InitKernelLogging(char* argv[]) {
     if (fd > 2) close(fd);
 
     android::base::InitLogging(argv, &KernelLogger);
-    klog_set_level(KLOG_NOTICE_LEVEL);
+    klog_set_level(KLOG_INFO_LEVEL);
 }
 
 int selinux_klog_callback(int type, const char *fmt, ...) {

libcutils/klog.cpp

@@ -37,15 +37,7 @@ void klog_set_level(int level) {
 }
 
 static int __open_klog(void) {
-    int fd = open("/dev/kmsg", O_WRONLY | O_CLOEXEC);
-    if (fd == -1) {
-        static const char* name = "/dev/__kmsg__";
-        if (mknod(name, S_IFCHR | 0600, (1 << 8) | 11) == 0) {
-            fd = open(name, O_WRONLY | O_CLOEXEC);
-            unlink(name);
-        }
-    }
-    return fd;
+    return TEMP_FAILURE_RETRY(open("/dev/kmsg", O_WRONLY | O_CLOEXEC));
 }
 
 #define LOG_BUF_MAX 512