Windows: fix utime() for read-only files

Starting with 5256b00 (Use git_mkstemp_mode instead of plain mkstemp to
create object files, 2010-02-22) utime() is invoked on read-only files.
This is not allowed on Windows and results in many warnings of the form

failed utime() on .git/objects/23/tmp_obj_VlgHlc: Permission denied

during a repack.  Fix it by making the file temporarily writable.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/compat/mingw.c b/compat/mingw.c
index ab65f77ab99500d99d24a9b7266669f37bb02cb2..59b18dc7ca51180426a0dbf11e651a93c5eedc81 100644 (file)
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -259,8 +259,17 @@ int mingw_utime (const char *file_name, const struct utimbuf *times)
        int fh, rc;
 
        /* must have write permission */
-       if ((fh = open(file_name, O_RDWR | O_BINARY)) < 0)
-               return -1;
+       DWORD attrs = GetFileAttributes(file_name);
+       if (attrs != INVALID_FILE_ATTRIBUTES &&
+           (attrs & FILE_ATTRIBUTE_READONLY)) {
+               /* ignore errors here; open() will report them */
+               SetFileAttributes(file_name, attrs & ~FILE_ATTRIBUTE_READONLY);
+       }
+
+       if ((fh = open(file_name, O_RDWR | O_BINARY)) < 0) {
+               rc = -1;
+               goto revert_attrs;
+       }
 
        time_t_to_filetime(times->modtime, &mft);
        time_t_to_filetime(times->actime, &aft);
@@ -270,6 +279,13 @@ int mingw_utime (const char *file_name, const struct utimbuf *times)
        } else
                rc = 0;
        close(fh);
+
+revert_attrs:
+       if (attrs != INVALID_FILE_ATTRIBUTES &&
+           (attrs & FILE_ATTRIBUTE_READONLY)) {
+               /* ignore errors again */
+               SetFileAttributes(file_name, attrs);
+       }
        return rc;
 }