liblog: add required function

Some Motorola proprietaries require a function named __android_log_loggable. This
change adds the function and solves problems with radio and other
binaries on qualcomm based Motorola phones. This code is activated with
TARGET_USES_MOTOROLA_LOG:=true

Change-Id: I722b42d34198c027f265c3cf9f220d9798814915

Author: epinter

liblog/Android.mk

@@ -64,15 +64,20 @@ LOCAL_LDLIBS := -lpthread
 LOCAL_CFLAGS := -DFAKE_LOG_DEVICE=1 -m64
 include $(BUILD_HOST_STATIC_LIBRARY)
 
+ifeq ($(TARGET_USES_MOTOROLA_LOG),true)
+LIBLOG_CFLAGS := -DMOTOROLA_LOG
+endif
 
 # Shared and static library for target
 # ========================================================
 include $(CLEAR_VARS)
+LOCAL_CFLAGS += $(LIBLOG_CFLAGS)
 LOCAL_MODULE := liblog
 LOCAL_SRC_FILES := $(liblog_sources)
 include $(BUILD_STATIC_LIBRARY)
 
 include $(CLEAR_VARS)
+LOCAL_CFLAGS += $(LIBLOG_CFLAGS)
 LOCAL_MODULE := liblog
 LOCAL_WHOLE_STATIC_LIBRARIES := liblog
 include $(BUILD_SHARED_LIBRARY)

liblog/logd_write.c

@@ -25,6 +25,12 @@
 #include <stdlib.h>
 #include <stdarg.h>
 
+#ifdef MOTOROLA_LOG
+#if HAVE_LIBC_SYSTEM_PROPERTIES
+#include <sys/system_properties.h>
+#endif
+#endif
+
 #include <cutils/logger.h>
 #include <cutils/logd.h>
 #include <cutils/log.h>
@@ -87,6 +93,96 @@ int __htclog_print_private(int a1, const char *a2, const char *fmt, ...)
 }
 #endif
 
+#ifdef MOTOROLA_LOG
+/* Fallback when there is neither log.tag.<tag> nor log.tag.DEFAULT.
+ * this is compile-time defaulted to "info". The log startup code
+ * looks at the build tags to see about whether it should be DEBUG...
+ * -- just as is done in frameworks/base/core/jni/android_util_Log.cpp
+ */
+static int prio_fallback = ANDROID_LOG_INFO;
+
+/*
+ * public interface so native code can see "should i log this"
+ * and behave similar to java Log.isLoggable() calls.
+ *
+ * NB: we have (level,tag) here to match the other __android_log entries.
+ * The Java side uses (tag,level) for its ordering.
+ * since the args are (int,char*) vs (char*,char*) we won't get strange
+ * swapped-the-strings errors.
+ */
+
+#define	LOGGING_PREFIX	"log.tag."
+#define	LOGGING_DEFAULT	"log.tag.DEFAULT"
+
+int __android_log_loggable(int prio, const char *tag)
+{
+    int nprio;
+
+#if	HAVE_LIBC_SYSTEM_PROPERTIES
+    char keybuf[PROP_NAME_MAX];
+    char results[PROP_VALUE_MAX];
+    int n;
+
+    /* we can NOT cache the log.tag.<tag> and log.tag.DEFAULT
+     * values because either one can be changed dynamically.
+     *
+     * damn, says the performance compulsive.
+     */
+
+    n = 0;
+    results[0] = '\0';
+    if (tag) {
+	memcpy (keybuf, LOGGING_PREFIX, strlen (LOGGING_PREFIX) + 1);
+	/* watch out for buffer overflow */
+	strncpy (keybuf + strlen (LOGGING_PREFIX), tag,
+		 sizeof (keybuf) - strlen (LOGGING_PREFIX));
+	keybuf[sizeof (keybuf) - 1] = '\0';
+	n = __system_property_get (keybuf, results);
+    }
+    if (n == 0) {
+	/* nothing yet, look for the global */
+	memcpy (keybuf, LOGGING_DEFAULT, sizeof (LOGGING_DEFAULT));
+	n = __system_property_get (keybuf, results);
+    }
+
+    if (n == 0) {
+	nprio = prio_fallback;
+    } else {
+	switch (results[0])
+	{
+	case 'E':
+	    nprio = ANDROID_LOG_ERROR;
+	    break;
+	case 'W':
+	    nprio = ANDROID_LOG_WARN;
+	    break;
+	case 'I':
+	    nprio = ANDROID_LOG_INFO;
+	    break;
+	case 'D':
+	    nprio = ANDROID_LOG_DEBUG;
+	    break;
+	case 'V':
+	    nprio = ANDROID_LOG_VERBOSE;
+	    break;
+	case 'S':
+	    nprio = ANDROID_LOG_SILENT;
+	    break;
+	default:
+	    /* unspecified or invalid */
+	    nprio = prio_fallback;
+	    break;
+	}
+    }
+#else
+    /* no system property routines, fallback to a default */
+    nprio = prio_fallback;
+#endif
+
+    return ((prio >= nprio) ? 1 : 0);
+}
+#endif
+
 static int __write_to_log_null(log_id_t log_fd, struct iovec *vec, size_t nr)
 {
     return -1;