78 lines
2.3 KiB
Go
78 lines
2.3 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package syspolicy
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import (
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"errors"
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"sync/atomic"
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"testing"
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)
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var (
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handlerUsed atomic.Bool
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handler Handler = defaultHandler{}
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)
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// Handler reads system policies from OS-specific storage.
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type Handler interface {
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// ReadString reads the policy setting's string value for the given key.
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// It should return ErrNoSuchKey if the key does not have a value set.
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ReadString(key string) (string, error)
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// ReadUInt64 reads the policy setting's uint64 value for the given key.
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// It should return ErrNoSuchKey if the key does not have a value set.
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ReadUInt64(key string) (uint64, error)
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// ReadBool reads the policy setting's boolean value for the given key.
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// It should return ErrNoSuchKey if the key does not have a value set.
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ReadBoolean(key string) (bool, error)
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// ReadStringArray reads the policy setting's string array value for the given key.
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// It should return ErrNoSuchKey if the key does not have a value set.
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ReadStringArray(key string) ([]string, error)
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}
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// ErrNoSuchKey is returned by a Handler when the specified key does not have a
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// value set.
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var ErrNoSuchKey = errors.New("no such key")
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// defaultHandler is the catch all syspolicy type for anything that isn't windows or apple.
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type defaultHandler struct{}
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func (defaultHandler) ReadString(_ string) (string, error) {
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return "", ErrNoSuchKey
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}
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func (defaultHandler) ReadUInt64(_ string) (uint64, error) {
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return 0, ErrNoSuchKey
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}
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func (defaultHandler) ReadBoolean(_ string) (bool, error) {
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return false, ErrNoSuchKey
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}
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func (defaultHandler) ReadStringArray(_ string) ([]string, error) {
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return nil, ErrNoSuchKey
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}
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// markHandlerInUse is called before handler methods are called.
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func markHandlerInUse() {
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handlerUsed.Store(true)
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}
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// RegisterHandler initializes the policy handler and ensures registration will happen once.
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func RegisterHandler(h Handler) {
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// Technically this assignment is not concurrency safe, but in the
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// event that there was any risk of a data race, we will panic due to
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// the CompareAndSwap failing.
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handler = h
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if !handlerUsed.CompareAndSwap(false, true) {
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panic("handler was already used before registration")
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}
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}
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func SetHandlerForTest(tb testing.TB, h Handler) {
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tb.Helper()
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oldHandler := handler
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handler = h
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tb.Cleanup(func() { handler = oldHandler })
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}
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