Hopefully fix the sim-eng build, part 2.

This is kinda gross, but I can't find a good way to check for the
existence of gettid(), except by finding its syscall number.  Then
might as well just use it rather than hope gettid's around, as it's
not in sim-eng.

Change-Id: Ieb7b39426dec08bd715b6fe1a9ab5b2801bdf775

1 files changed, 20 insertions, 4 deletions

diff --git a/core/jni/android_util_Binder.cpp b/core/jni/android_util_Binder.cpp
index 2fd68b8..901be58 100644
--- a/core/jni/android_util_Binder.cpp
+++ b/core/jni/android_util_Binder.cpp
@@ -21,9 +21,10 @@
 #include "JNIHelp.h"
 
 #include <fcntl.h>
+#include <stdio.h>
 #include <sys/stat.h>
+#include <sys/syscall.h>
 #include <sys/types.h>
-#include <stdio.h>
 #include <unistd.h>
 
 #include <utils/Atomic.h>
@@ -844,6 +845,19 @@ static void conditionally_log_binder_call(int64_t start_millis,
     android_bWriteLog(LOGTAG_BINDER_OPERATION, buf, pos - buf);
 }
 
+// We only measure binder call durations to potentially log them if
+// we're on the main thread.  Unfortunately sim-eng doesn't seem to
+// have gettid, so we just ignore this and don't log if we can't
+// get the thread id.
+static bool should_time_binder_calls() {
+#ifdef __NR_gettid
+  return (getpid() == syscall(__NR_gettid));
+#else
+#warning no gettid(), so not logging Binder calls...
+  return false;
+#endif
+}
+
 static jboolean android_os_BinderProxy_transact(JNIEnv* env, jobject obj,
                                                 jint code, jobject dataObj,
                                                 jobject replyObj, jint flags)
@@ -873,15 +887,17 @@ static jboolean android_os_BinderProxy_transact(JNIEnv* env, jobject obj,
             target, obj, code);
 
     // Only log the binder call duration for things on the Java-level main thread.
-    const bool is_main_thread = (getpid() == gettid());
+    // But if we don't
+    const bool time_binder_calls = should_time_binder_calls();
+
     int64_t start_millis;
-    if (is_main_thread) {
+    if (time_binder_calls) {
         start_millis = uptimeMillis();
     }
     //printf("Transact from Java code to %p sending: ", target); data->print();
     status_t err = target->transact(code, *data, reply, flags);
     //if (reply) printf("Transact from Java code to %p received: ", target); reply->print();
-    if (is_main_thread) {
+    if (time_binder_calls) {
         conditionally_log_binder_call(start_millis, target, code);
     }