base: disallow close() on unique_fd.
unique_fd's implicit conversion to int allows it to be passed to
close(2), which is dangerous because unique_fd will think that it still
has ownership of the now-closed fd. Disallow this by providing an
overload for close that's tagged with an attribute that gives a
compile-time error.
Test: m
Change-Id: I514591335b337f2f57c1df371cf3979304aea17c
diff --git a/base/include/android-base/unique_fd.h b/base/include/android-base/unique_fd.h
index 869e60f..c323311 100644
--- a/base/include/android-base/unique_fd.h
+++ b/base/include/android-base/unique_fd.h
@@ -95,4 +95,14 @@
} // namespace base
} // namespace android
+template <typename T>
+int close(const android::base::unique_fd_impl<T>&)
+#if defined(__clang__)
+ __attribute__((__unavailable__(
+#else
+ __attribute__((__error__(
+#endif
+ "close called on unique_fd"
+ )));
+
#endif // ANDROID_BASE_UNIQUE_FD_H