The mac_prepare family of functions allocates the appropriate amount of storage and initializes *mac for use by mac_get(3). When the resulting label is passed into the mac_get(3) functions, the kernel will attempt to fill in the label elements specified when the label was prepared. Elements are specified in a nul-terminated string, using commas to delimit fields. Element names may be prefixed with the ? character to indicate that a failure by the kernel to retrieve that element should not be considered fatal.
The mac_prepare function accepts a list of policy names as a parameter, and allocates the storage to fit those label elements accordingly. The remaining functions in the family make use of system defaults defined in mac.conf(5) instead of an explicit elements argument, deriving the default from the specified object type.
mac_prepare_type allocates the storage to fit an object label of the type specified by the name argument. The mac_prepare_file_label, mac_prepare_ifnet_label, and mac_prepare_process_label functions are equivalent to invocations of mac_prepare_type with arguments of "file", "ifnet", and "process" respectively.
mac(3), mac_free(3), mac_get(3), mac_is_present_np(3), mac_set(3), mac(4), mac.conf(5), maclabel(7)