Fix get_dirent_type() for Windows junction points.

Commit 87e6ed7c8 added code that intended to report Windows "junction
points" as DT_LNK (the same way we report symlinks on Unix).  Windows
junction points are *also* directories according to the Windows
attributes API, and we were reporting them as as DT_DIR.  Change the
order we check the attribute flags, to prioritize DT_LNK.

If at some point we start using Windows' recently added real symlinks
and need to distinguish them from junction points, we may need to
rethink this, but for now this continues the tradition of wrapper
functions that treat junction points as symlinks.

Back-patch to 14, where get_dirent_type() landed.

Reviewed-by: Michael Paquier <[email protected]>
Reviewed-by: Alvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/CA%2BhUKGLzLK4PUPx0_AwXEWXOYAejU%3D7XpxnYE55Y%2Be7hB2N3FA%40mail.gmail.com
Discussion: https://postgr.es/m/20220721111751.x7hod2xgrd76xr5c%40alvherre.pgsql

1 files changed, 10 insertions, 6 deletions

diff --git a/src/port/dirent.c b/src/port/dirent.c
index f67bbf7f71..10ea4bdd42 100644
--- a/src/port/dirent.c
+++ b/src/port/dirent.c
@@ -106,13 +106,17 @@ readdir(DIR *d)
 	}
 	strcpy(d->ret.d_name, fd.cFileName);	/* Both strings are MAX_PATH long */
 	d->ret.d_namlen = strlen(d->ret.d_name);
-	/* The only identified types are: directory, regular file or symbolic link */
-	if ((fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0)
-		d->ret.d_type = DT_DIR;
-	/* For reparse points dwReserved0 field will contain the ReparseTag */
-	else if ((fd.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) != 0 &&
-			 (fd.dwReserved0 == IO_REPARSE_TAG_MOUNT_POINT))
+
+	/*
+	 * For reparse points dwReserved0 field will contain the ReparseTag.  We
+	 * check this first, because reparse points are also reported as
+	 * directories.
+	 */
+	if ((fd.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) != 0 &&
+		(fd.dwReserved0 == IO_REPARSE_TAG_MOUNT_POINT))
 		d->ret.d_type = DT_LNK;
+	else if ((fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0)
+		d->ret.d_type = DT_DIR;
 	else
 		d->ret.d_type = DT_REG;