Basic, which can be modified by the owner of the calling process
Privileged, which can be modified only by privileged (root) callers
System, which is fixed for the duration of the operating system instance
A resource control is guaranteed to have one system value, which is defined by the system, or resource provider. The system value represents how much of the resource the current implementation of the operating system is capable of providing.
Any number of privileged values can be defined, and only one basic value is allowed. Operations that are performed without specifying a privilege value are assigned a basic privilege by default.
The privilege level for a resource control value is defined in the privilege field of the resource control block as RCTL_BASIC, RCTL_PRIVILEGED, or RCTL_SYSTEM. See setrctl(2) for more information. You can use the prctl command to modify values that are associated with basic and privileged levels.