umask

set file mode creation mask (umask)

This function sets the mask used for creating new files and device nodes to "mask & 0777".

Typical umask values would be @022 which creates new files with permissions like "-rw-r--r--" or "-rwxr-xr-x", and @002 which creates new files with permissions like "-rw-rw-r--" or "-rwxrwxr-x".

The default umask is @022. This is important because it means that directories and device nodes will be created with @0644 or @0755 mode even if you specify @0777.

See also get_umask, umask(2), mknod, mkdir.

This call returns the previous umask.

Parameters:

this	A GuestfsSession object

Returns:

the returned value, or -1 on error