Fix bug #16299 with assertion violation in set-default-file-modes on Windows.

 src/w32.c (sys_umask): New function.

 nt/inc/ms-w32.h (umask) [emacs]: Redirect to sys_umask.

1 files changed, 29 insertions, 0 deletions

diff --git a/src/w32.c b/src/w32.c
index dde74bfcdd9..3fdb673b63f 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -5265,6 +5265,35 @@ utime (const char *name, struct utimbuf *times)
   return 0;
 }
 
+/* Emacs expects us to support the traditional octal form of the mode
+   bits, which is not what msvcrt.dll wants.  */
+
+#define WRITE_USER 00200
+
+int
+sys_umask (int mode)
+{
+  static int current_mask;
+  int retval, arg = 0;
+
+  /* The only bit we really support is the write bit.  Files are
+     always readable on MS-Windows, and the execute bit does not exist
+     at all.  */
+  /* FIXME: if the GROUP and OTHER bits are reset, we should use ACLs
+     to prevent access by other users on NTFS.  */
+  if ((mode & WRITE_USER) != 0)
+    arg |= S_IWRITE;
+
+  retval = _umask (arg);
+  /* Merge into the return value the bits they've set the last time,
+     which msvcrt.dll ignores and never returns.  Emacs insists on its
+     notion of mask being identical to what we return.  */
+  retval |= (current_mask & ~WRITE_USER);
+  current_mask = mode;
+
+  return retval;
+}
+
 
 /* Symlink-related functions.  */
 #ifndef SYMBOLIC_LINK_FLAG_DIRECTORY