postgres.git / summary / log / commit / refs

commit    4fc6b6eefcf98f79211bb790ee890ebcb05c178d
Author:   Thomas Munro <tmunro@postgresql.org>
Date:     Thu Jul 28 02:13:37 2022 +0000

    Fix get_dirent_type() for symlinks on MinGW/MSYS.
    
    On Windows with MSVC, get_dirent_type() was recently made to return
    DT_LNK for junction points by commit 9d3444dc, which fixed some
    defective dirent.c code.
    
    On Windows with Cygwin, get_dirent_type() already worked for symlinks,
    as it does on POSIX systems, because Cygwin has its own fake symlinks
    that behave like POSIX (on closer inspection, Cygwin's dirent has the
    BSD d_type extension but it's probably always DT_UNKNOWN, so we fall
    back to lstat(), which understands Cygwin symlinks with S_ISLNK()).
    
    On Windows with MinGW/MSYS, we need extra code, because the MinGW
    runtime has its own readdir() without d_type, and the lstat()-based
    fallback has no knowledge of our convention for treating junctions as
    symlinks.
    
    Back-patch to 14, where get_dirent_type() landed.
    
    Reported-by: Andrew Dunstan <andrew@dunslane.net>
    Discussion: https://postgr.es/m/b9ddf605-6b36-f90d-7c30-7b3e95c46276%40dunslane.net


 src/common/file_utils.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/common/file_utils.c b/src/common/file_utils.c
index 19d308ad1f9..966b987d648 100644
--- a/src/common/file_utils.c
+++ b/src/common/file_utils.c
@@ -465,5 +465,21 @@ get_dirent_type(const char *path,
 #endif
 	}
 
+#if defined(WIN32) && !defined(_MSC_VER)
+
+	/*
+	 * If we're on native Windows (not Cygwin, which has its own POSIX
+	 * symlinks), but not using the MSVC compiler, then we're using a
+	 * readdir() emulation provided by the MinGW runtime that has no d_type.
+	 * Since the lstat() fallback code reports junction points as directories,
+	 * we need an extra system call to check if we should report them as
+	 * symlinks instead, following our convention.
+	 */
+	if (result == PGFILETYPE_DIR &&
+		!look_through_symlinks &&
+		pgwin32_is_junction(path))
+		result = PGFILETYPE_LNK;
+#endif
+
 	return result;
 }


[parent: 5253519b27d3]