libbase: add Fdopendir that takes a unique_fd.

Using fdopendir with unique_fd correctly is more annoying than it
should be, because fdopendir doesn't close the file descriptor
received upon failure.

Add an android::base::Fdopendir that does that handles the failure
case.

Bug: 118818285
Test: treehugger
Change-Id: I5dbbe0eb82242bc7716f84735ffc7644febcfd65

1 files changed, 12 insertions, 0 deletions

diff --git a/base/include/android-base/unique_fd.h b/base/include/android-base/unique_fd.h
index cd2dc0416..4e3879b99 100644
--- a/base/include/android-base/unique_fd.h
+++ b/base/include/android-base/unique_fd.h
@@ -19,6 +19,7 @@
 #include <fcntl.h>
 
 #if !defined(_WIN32)
+#include <dirent.h>
 #include <sys/socket.h>
 #endif
 
@@ -211,6 +212,17 @@ inline FILE* Fdopen(unique_fd&& ufd, const char* mode) {
   return file;
 }
 
+// Using fdopendir with unique_fd correctly is more annoying than it should be,
+// because fdopen doesn't close the file descriptor received upon failure.
+inline DIR* Fdopendir(unique_fd&& ufd) {
+  int fd = ufd.release();
+  DIR* dir = fdopendir(fd);
+  if (dir == nullptr) {
+    close(fd);
+  }
+  return dir;
+}
+
 #endif  // !defined(_WIN32)
 
 }  // namespace base