- If UNC path for DFS is mounted to a drive with drive letter, the error "Too many levels of symbolic links" occurs when accessing to that drive. This is because GetDosDeviceW() returns unexpected string such as "\Device\Mup\DfsClient\;Z:000000000003fb89\dfsserver \dfs\linkname" for the mounted UNC path "\??\UNC\fileserver\share". This patch adds a workaround for this issue.
Addresses: https://cygwin.com/pipermail/cygwin/2022-March/250979.html --- winsup/cygwin/path.cc | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc index 4ad4e0821..dd8f6c043 100644 --- a/winsup/cygwin/path.cc +++ b/winsup/cygwin/path.cc @@ -3527,7 +3527,7 @@ restart: int remlen = QueryDosDeviceW (drive, remote, MAX_PATH); if (remlen < 3) goto file_not_symlink; /* fallback */ - remlen -= 2; + remlen -= 2; /* Two L'\0' */ if (remote[remlen - 1] == L'\\') remlen--; @@ -3535,20 +3535,27 @@ restart: UNICODE_STRING rpath; RtlInitCountedUnicodeString (&rpath, remote, remlen * sizeof (WCHAR)); + const int uncp_len = + ro_u_uncp.Length / sizeof (WCHAR) - 1; if (RtlEqualUnicodePathPrefix (&rpath, &ro_u_uncp, TRUE)) - remlen -= 6; + { + remlen -= uncp_len; + p = remote + uncp_len; + } else if ((p = wcschr (remote, L';')) && p + 3 < remote + remlen && wcsncmp (p + 1, drive, 2) == 0 && (p = wcschr (p + 3, L'\\'))) - remlen -= p - remote - 1; + remlen -= p - remote; else goto file_not_symlink; /* fallback */ + if (wcsncasecmp (fpath.Buffer + uncp_len, p, remlen)) + goto file_not_symlink; /* fallback (not expected) */ /* Hackfest */ fpath.Buffer[4] = drive[0]; /* Drive letter */ fpath.Buffer[5] = L':'; - WCHAR *to = fpath.Buffer + 6; - WCHAR *from = to + remlen; + WCHAR *to = fpath.Buffer + 6; /* Next to L':' */ + WCHAR *from = fpath.Buffer + uncp_len + remlen; memmove (to, from, (wcslen (from) + 1) * sizeof (WCHAR)); fpath.Length -= (from - to) * sizeof (WCHAR); -- 2.35.1
