57 lines
2.1 KiB
OCaml
57 lines
2.1 KiB
OCaml
(* (c) 2017 Hannes Mehnert, all rights reserved *)
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(** A tree data structure tracking dynamic resource usage.
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Considering delegation of resources to someone, and further delegation
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to others - using a process which is not controlled by the authority -
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requires runtime tracking of these delegations and the actual usage:
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If Alice may create 2 virtual machines, and she delegates the same
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capability further to both Bob and Charlie, the authority must still enforce
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that Alice, Bob, and Charlie are able to run 2 virtual machines in total,
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rather than 2 each. *)
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(** The type of the resource tree. *)
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type t
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(** The type of the resource tree entry. *)
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type entry
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(** [empty] is the empty tree. *)
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val empty : t
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(** [pp ppf t] pretty prints the tree. *)
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val pp : t Fmt.t
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(** [pp_entry ppf e] pretty prints the entry. *)
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val pp_entry : entry Fmt.t
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(** [check_dynamic t vm delegates] checks whether creating [vm] would violate
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the policies of the [delegates] with respect to the running vms. *)
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val check_dynamic : t ->
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Vmm_core.vm_config -> (string * Vmm_core.delegation) list ->
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(unit, [> `Msg of string ]) result
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(** [exists t id] is [true] if the [id] already exists, [false] otherwise. *)
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val exists : t -> Vmm_core.id -> bool
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(** [find t id] is either [Some entry] or [None]. *)
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val find : t -> Vmm_core.id -> entry option
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(** [find_vm t id] is either [Some vm] or [None]. *)
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val find_vm : t -> Vmm_core.id -> Vmm_core.vm option
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(** [iter f entry] applies [f] to each vm of [entry]. *)
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val iter : (Vmm_core.vm -> unit) -> entry -> unit
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(** [fold f entry acc] folds [f] over [entry]. *)
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val fold : ('a -> Vmm_core.vm -> 'a) -> 'a -> entry -> 'a
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(** [insert t id vm] inserts [vm] under [id] in [t], and returns the new [t] or
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an error. It also updates the resource usages on the path. *)
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val insert : t -> Vmm_core.id -> Vmm_core.vm -> (t, [> `Msg of string]) result
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(** [remove t id vm] removes [id] from [t], and returns the new [t] or an
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error. This also updates the resources usages on the path. *)
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val remove : t -> Vmm_core.id -> Vmm_core.vm -> (t, [> `Msg of string]) result
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