commit 1d35761c67c7d5f0d4cb570d2064e3ac5702d98c
author Yao Chen <yaochen@google.com> Thu Nov 08 15:43:08 2018 -0800
committer Yao Chen <yaochen@google.com> Fri Dec 07 11:02:08 2018 -0800
tree 8046eb5da0d948272e1c9dc652055378e9fdc21f
parent bcc2d60826635870e1f53856f81f941378e199e0

Log the last error code of StatsLog failures

Test: builds and manual test
Bug: 80538532

Change-Id: I7f9d0e22b7ad4295dd787f6cb409bfb3342a7b27
Merged-In: I7f9d0e22b7ad4295dd787f6cb409bfb3342a7b27
(cherry picked from commit cb3527794cadfb828589e338602a08f464e40f83)

libstats/statsd_writer.c

diff --git a/libstats/statsd_writer.c b/libstats/statsd_writer.c
index 88f7d44..f00fc2d 100644
--- a/libstats/statsd_writer.c
+++ b/libstats/statsd_writer.c
@@ -48,6 +48,7 @@
 
 static pthread_mutex_t log_init_lock = PTHREAD_MUTEX_INITIALIZER;
 static atomic_int dropped = 0;
+static atomic_int log_error = 0;
 
 void statsd_writer_init_lock() {
     /*
@@ -150,8 +151,9 @@
     return 1;
 }
 
-static void statsdNoteDrop() {
+static void statsdNoteDrop(int error) {
     atomic_fetch_add_explicit(&dropped, 1, memory_order_relaxed);
+    atomic_exchange_explicit(&log_error, error, memory_order_relaxed);
 }
 
 static int statsdWrite(struct timespec* ts, struct iovec* vec, size_t nr) {
@@ -202,7 +204,8 @@
         if (snapshot) {
             android_log_event_int_t buffer;
             header.id = LOG_ID_STATS;
-            buffer.header.tag = htole32(LIBLOG_LOG_TAG);
+            // store the last log error in the tag field. This tag field is not used by statsd.
+            buffer.header.tag = htole32(atomic_load(&log_error));
             buffer.payload.type = EVENT_TYPE_INT;
             buffer.payload.data = htole32(snapshot);