84 lines
2.7 KiB
Go
84 lines
2.7 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Package namespaces provides tools for working with namespaces across
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// containerd.
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//
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// Namespaces collect resources such as containers and images, into a unique
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// identifier space. This means that two applications can use the same
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// identifiers and not conflict while using containerd.
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//
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// This package can be used to ensure that client and server functions
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// correctly store the namespace on the context.
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package namespaces
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import (
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"regexp"
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"github.com/containerd/containerd/errdefs"
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"github.com/pkg/errors"
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)
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const (
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maxLength = 76
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alpha = `[A-Za-z]`
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alphanum = `[A-Za-z0-9]+`
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label = alpha + alphanum + `(:?[-]+` + alpha + alphanum + `)*`
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)
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var (
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// namespaceRe validates that a namespace matches valid identifiers.
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//
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// Rules for domains, defined in RFC 1035, section 2.3.1, are used for
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// namespaces.
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namespaceRe = regexp.MustCompile(reAnchor(label + reGroup("[.]"+reGroup(label)) + "*"))
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)
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// Validate returns nil if the string s is a valid namespace.
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//
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// To allow such namespace identifiers to be used across various contexts
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// safely, the character set has been restricted to that defined for domains in
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// RFC 1035, section 2.3.1. This will make namespace identifiers safe for use
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// across networks, filesystems and other media.
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//
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// The identifier specification departs from RFC 1035 in that it allows
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// "labels" to start with number and only enforces a total length restriction
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// of 76 characters.
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//
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// While the character set may be expanded in the future, namespace identifiers
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// are guaranteed to be safely used as filesystem path components.
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//
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// For the most part, this doesn't need to be called directly when using the
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// context-oriented functions.
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func Validate(s string) error {
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if len(s) > maxLength {
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return errors.Wrapf(errdefs.ErrInvalidArgument, "namespace %q greater than maximum length (%d characters)", s, maxLength)
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}
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if !namespaceRe.MatchString(s) {
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return errors.Wrapf(errdefs.ErrInvalidArgument, "namespace %q must match %v", s, namespaceRe)
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}
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return nil
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}
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func reGroup(s string) string {
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return `(?:` + s + `)`
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}
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func reAnchor(s string) string {
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return `^` + s + `$`
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}
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