From e44aa092c5fdcb15f2ae0cfab77c3fc2edc93766 Mon Sep 17 00:00:00 2001
From: Steven Moreland <smoreland@google.com>
Date: Fri, 15 Dec 2023 23:12:56 +0000
Subject: [PATCH] uevent.c: avoid POLLERR infinite loop

I have not reproduced this infinite loop.
An infinite loop may be more useful to debug.

Note, libhardware_legacy AIDL interface dependency
already includes liblog, so this won't change
which libraries are loaded.

Bug: 300009377
Test: N/A
Change-Id: I1f5545456e7074823f0f9df35496cbf5a2a012a4
---
 Android.bp |  1 +
 uevent.c   | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/Android.bp b/Android.bp
index 409db5d..871b1f9 100644
--- a/Android.bp
+++ b/Android.bp
@@ -79,6 +79,7 @@ cc_library_shared {
     shared_libs: [
         "android.system.suspend-V1-ndk",
         "libdl",
+        "liblog",
     ],
 
     header_libs: [
diff --git a/uevent.c b/uevent.c
index e40aa2e..0dcae79 100644
--- a/uevent.c
+++ b/uevent.c
@@ -16,6 +16,8 @@
 
 #include <hardware_legacy/uevent.h>
 
+#include <log/log.h>
+
 #include <malloc.h>
 #include <string.h>
 #include <unistd.h>
@@ -94,6 +96,16 @@ int uevent_next_event(char* buffer, int buffer_length)
                 return count;
             } 
         }
+
+        if (nr > 0 && (fds.revents & POLLERR)) {
+            int error = 0;
+            socklen_t errlen = sizeof(error);
+            getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &errlen);
+
+            // see b/300009377, this used to be an infinite loop
+            // abort to try to recover
+            LOG_ALWAYS_FATAL("Uevent POLLERR: %s, on FD %d", strerror(error), fd);
+        }
     }
     
     // won't get here