Cygwin: symlink_info::check: avoid assertion failure

On certain error conditions there is a code snippet that checks
whether the last component of the path has a trailing dot or space or
a leading space.  Skip this check if the last component is empty,
i.e., if the path ends with a backslash.  This avoids an assertion
failure if the trailing backslash is the only backslash in the path,
as is the case for a DOS drive 'X:\'.

Addresses: https://cygwin.com/ml/cygwin/2019-12/msg00016.html

diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
index f610035781dec3bcbaea720752c6d46c2874fa4a..b5efd61b25b232511e96c439e8bc2cbe55e83d53 100644 (file)
--- a/winsup/cygwin/path.cc
+++ b/winsup/cygwin/path.cc
@@ -2895,7 +2895,8 @@ restart:
             slow down normal operation.  This extra check only kicks in if
             we encountered a STATUS_OBJECT_NAME_NOT_FOUND *and* we didn't
             already attach a suffix. */
-         if (!restarted && !*ext_here && !(mount_flags & MOUNT_DOS))
+         if (!restarted && !*ext_here && ext_here[-1] != '\\'
+             && !(mount_flags & MOUNT_DOS))
            {
              /* Check for trailing dot or space or leading space in
                 last component. */