1 files changed, 75 insertions, 0 deletions
diff --git a/libcutils/trace.c b/libcutils/trace.c
new file mode 100644
index 0000000..15c8a98
--- /dev/null
+++ b/libcutils/trace.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2012 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 <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <cutils/atomic.h>
+#include <cutils/compiler.h>
+#include <cutils/properties.h>
+#include <cutils/trace.h>
+
+#define LOG_TAG "cutils-trace"
+#include <cutils/log.h>
+
+int32_t               atrace_is_ready     = 0;
+int                   atrace_marker_fd    = -1;
+uint64_t              atrace_enabled_tags = ATRACE_TAG_NOT_READY;
+static pthread_once_t atrace_once_control = PTHREAD_ONCE_INIT;
+
+// Read the sysprop and return the value tags should be set to
+static uint64_t atrace_get_property()
+{
+    char value[PROPERTY_VALUE_MAX];
+    char *endptr;
+    uint64_t tags;
+
+    property_get("debug.atrace.tags.enableflags", value, "0");
+    errno = 0;
+    tags = strtoull(value, &endptr, 0);
+    if (value[0] == '\0' || *endptr != '\0') {
+        ALOGE("Error parsing trace property: Not a number: %s", value);
+        return 0;
+    } else if (errno == ERANGE || tags == ULLONG_MAX) {
+        ALOGE("Error parsing trace property: Number too large: %s", value);
+        return 0;
+    }
+    return (tags | ATRACE_TAG_ALWAYS) & ATRACE_TAG_VALID_MASK;
+}
+
+static void atrace_init_once()
+{
+    atrace_marker_fd = open("/sys/kernel/debug/tracing/trace_marker", O_WRONLY);
+    if (atrace_marker_fd == -1) {
+        ALOGE("Error opening trace file: %s (%d)", strerror(errno), errno);
+        atrace_enabled_tags = 0;
+        goto done;
+    }
+
+    atrace_enabled_tags = atrace_get_property();
+
+done:
+    android_atomic_release_store(1, &atrace_is_ready);
+}
+
+void atrace_setup()
+{
+    pthread_once(&atrace_once_control, atrace_init_once);
+}