ALR

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/*
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 * ALR - Any Linux Repository
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 * Copyright (C) 2024 Евгений Храмов
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 *
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 * This program is free software: you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation, either version 3 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
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 */
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package handlers
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import (
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	"context"
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	"io"
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	"io/fs"
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	"path/filepath"
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	"strings"
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	"time"
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	"golang.org/x/exp/slices"
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	"mvdan.cc/sh/v3/interp"
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)
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func RestrictedReadDir(allowedPrefixes ...string) interp.ReadDirHandlerFunc {
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	return func(ctx context.Context, s string) ([]fs.FileInfo, error) {
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		path := filepath.Clean(s)
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		for _, allowedPrefix := range allowedPrefixes {
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			if strings.HasPrefix(path, allowedPrefix) {
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				return interp.DefaultReadDirHandler()(ctx, s)
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			}
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		}
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		return nil, fs.ErrNotExist
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	}
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}
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func RestrictedStat(allowedPrefixes ...string) interp.StatHandlerFunc {
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	return func(ctx context.Context, s string, b bool) (fs.FileInfo, error) {
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		path := filepath.Clean(s)
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		for _, allowedPrefix := range allowedPrefixes {
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			if strings.HasPrefix(path, allowedPrefix) {
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				return interp.DefaultStatHandler()(ctx, s, b)
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			}
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		}
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		return nil, fs.ErrNotExist
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	}
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}
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func RestrictedOpen(allowedPrefixes ...string) interp.OpenHandlerFunc {
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	return func(ctx context.Context, s string, i int, fm fs.FileMode) (io.ReadWriteCloser, error) {
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		path := filepath.Clean(s)
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		for _, allowedPrefix := range allowedPrefixes {
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			if strings.HasPrefix(path, allowedPrefix) {
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				return interp.DefaultOpenHandler()(ctx, s, i, fm)
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			}
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		}
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		return NopRWC{}, nil
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	}
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}
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func RestrictedExec(allowedCmds ...string) interp.ExecHandlerFunc {
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	return func(ctx context.Context, args []string) error {
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		if slices.Contains(allowedCmds, args[0]) {
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			return interp.DefaultExecHandler(2*time.Second)(ctx, args)
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		}
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		return nil
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	}
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}
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