From abf8a2c608cb5f0d1523ab7d0c56e0da8a09cc87 Mon Sep 17 00:00:00 2001
From: Jun Jiang <jun.a.jiang@intel.com>
Date: Tue, 29 Apr 2014 14:22:10 +0800
Subject: [PATCH] Add error message for hints when exceptions occur during
 binder transactions.

It can help to detect some kind of error, such as why GraphicBuffer::flatten
will crash when handle is null.

Change-Id: I703cd035b96edb7afb324cf24d8230d4e55f4f52
Signed-off-by: Jun Jiang <jun.a.jiang@intel.com>
---
 libs/binder/Parcel.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index 159003d16..169e50339 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -25,6 +25,7 @@
 #include <binder/ProcessState.h>
 #include <binder/TextOutput.h>
 
+#include <errno.h>
 #include <utils/Debug.h>
 #include <utils/Log.h>
 #include <utils/String8.h>
@@ -1229,7 +1230,11 @@ status_t Parcel::read(FlattenableHelperInterface& val) const
     status_t err = NO_ERROR;
     for (size_t i=0 ; i<fd_count && err==NO_ERROR ; i++) {
         fds[i] = dup(this->readFileDescriptor());
-        if (fds[i] < 0) err = BAD_VALUE;
+        if (fds[i] < 0) {
+            err = BAD_VALUE;
+            ALOGE("dup() failed in Parcel::read, i is %d, fds[i] is %d, fd_count is %d, error: %s",
+                i, fds[i], fd_count, strerror(errno));
+        }
     }
 
     if (err == NO_ERROR) {