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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2023 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package interfaces
import (
"fmt"
"path/filepath"
"strings"
)
// EnsureDirSpec contains the information required to ensure the existence of a directory.
// MustExistDir is the prefix of EnsureDir and must exist as prerequisite for creation for
// the remainder of missing directories of EnsureDir.
type EnsureDirSpec struct {
MustExistDir string
EnsureDir string
}
// Validate returns an error if the ensure directory specification is not valid.
func (spec *EnsureDirSpec) Validate() error {
if spec.MustExistDir != filepath.Clean(spec.MustExistDir) {
return fmt.Errorf("directory that must exist %q is not a clean path", spec.MustExistDir)
}
if spec.EnsureDir != filepath.Clean(spec.EnsureDir) {
return fmt.Errorf("directory to ensure %q is not a clean path", spec.EnsureDir)
}
hasEnvPrefix := func(path string) (hasPrefix bool, envPrefix string) {
pathElements := strings.Split(path, string(filepath.Separator))
if strings.HasPrefix(pathElements[0], "$") {
return true, pathElements[0]
}
return false, ""
}
// Extend this allowed list as required
allowedEnvPrefixes := []string{"$HOME"}
isAllowedEnvPrefix := func(envPrefix string) (isAllowed bool) {
for _, allowedEnvPrefix := range allowedEnvPrefixes {
if envPrefix == allowedEnvPrefix {
return true
}
}
return false
}
if doCheck, envPrefix := hasEnvPrefix(spec.MustExistDir); doCheck {
if !isAllowedEnvPrefix(envPrefix) {
return fmt.Errorf("directory that must exist %q prefix %q is not allowed", spec.MustExistDir, envPrefix)
}
} else if !filepath.IsAbs(spec.MustExistDir) {
return fmt.Errorf("directory that must exist %q is not an absolute path", spec.MustExistDir)
}
if doCheck, envPrefix := hasEnvPrefix(spec.EnsureDir); doCheck {
if !isAllowedEnvPrefix(envPrefix) {
return fmt.Errorf("directory to ensure %q prefix %q is not allowed", spec.EnsureDir, envPrefix)
}
} else if !filepath.IsAbs(spec.EnsureDir) {
return fmt.Errorf("directory to ensure %q is not an absolute path", spec.EnsureDir)
}
isParent := spec.EnsureDir != spec.MustExistDir && (spec.MustExistDir == "/" || strings.HasPrefix(spec.EnsureDir, spec.MustExistDir+string(filepath.Separator)))
if !isParent {
return fmt.Errorf("directory that must exist %q is not a parent of directory to ensure %q", spec.MustExistDir, spec.EnsureDir)
}
return nil
}
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