Fail explicitly on length overflow.

Instead of aborting when FileMap::create detects an overflow, detect the
overflow directly and fail the call.

Bug: 156997193

Test: Ran unit tests, including new unit test that aborted before.
Merged-In: Ie49975b8949fd12bbde14346ec9bbb774ef88a51
Change-Id: Ie49975b8949fd12bbde14346ec9bbb774ef88a51
(cherry picked from commit 68604b9c29b5bd11e2e2dbb848d6b364bf627d21)

1 files changed, 13 insertions, 0 deletions

diff --git a/libutils/FileMap_test.cpp b/libutils/FileMap_test.cpp
index 9f7ce85ca..fd1c9b0a0 100644
--- a/libutils/FileMap_test.cpp
+++ b/libutils/FileMap_test.cpp
@@ -52,3 +52,16 @@ TEST(FileMap, large_offset) {
     ASSERT_EQ(0u, m.getDataLength());
     ASSERT_EQ(offset, m.getDataOffset());
 }
+
+TEST(FileMap, offset_overflow) {
+    // Make sure that an end that overflows SIZE_MAX will not abort.
+    // See http://b/156997193.
+    TemporaryFile tf;
+    ASSERT_TRUE(tf.fd != -1);
+
+    off64_t offset = 200;
+    size_t length = SIZE_MAX;
+
+    android::FileMap m;
+    ASSERT_FALSE(m.create("test", tf.fd, offset, length, true));
+}