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 distro
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import (
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	"context"
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	"os"
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	"strings"
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	"plemya-x.ru/alr/internal/shutils/handlers"
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	"mvdan.cc/sh/v3/expand"
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	"mvdan.cc/sh/v3/interp"
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	"mvdan.cc/sh/v3/syntax"
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)
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// OSRelease contains information from an os-release file
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type OSRelease struct {
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	Name             string
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	PrettyName       string
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	ID               string
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	Like             []string
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	VersionID        string
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	ANSIColor        string
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	HomeURL          string
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	DocumentationURL string
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	SupportURL       string
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	BugReportURL     string
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	Logo             string
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}
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var parsed *OSRelease
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// OSReleaseName returns a struct parsed from the system's os-release
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// file. It checks /etc/os-release as well as /usr/lib/os-release.
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// The first time it's called, it'll parse the os-release file.
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// Subsequent calls will return the same value.
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func ParseOSRelease(ctx context.Context) (*OSRelease, error) {
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	if parsed != nil {
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		return parsed, nil
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	}
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	fl, err := os.Open("/usr/lib/os-release")
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	if err != nil {
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		fl, err = os.Open("/etc/os-release")
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		if err != nil {
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			return nil, err
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		}
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	}
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	file, err := syntax.NewParser().Parse(fl, "/usr/lib/os-release")
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	if err != nil {
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		return nil, err
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	}
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	fl.Close()
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	// Create new shell interpreter with nop open, exec, readdir, and stat handlers
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	// as well as no environment variables in order to prevent vulnerabilities
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	// caused by changing the os-release file.
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	runner, err := interp.New(
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		interp.OpenHandler(handlers.NopOpen),
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		interp.ExecHandler(handlers.NopExec),
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		interp.ReadDirHandler(handlers.NopReadDir),
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		interp.StatHandler(handlers.NopStat),
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		interp.Env(expand.ListEnviron()),
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	)
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	if err != nil {
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		return nil, err
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	}
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	err = runner.Run(ctx, file)
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	if err != nil {
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		return nil, err
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	}
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	out := &OSRelease{
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		Name:             runner.Vars["NAME"].Str,
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		PrettyName:       runner.Vars["PRETTY_NAME"].Str,
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		ID:               runner.Vars["ID"].Str,
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		VersionID:        runner.Vars["VERSION_ID"].Str,
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		ANSIColor:        runner.Vars["ANSI_COLOR"].Str,
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		HomeURL:          runner.Vars["HOME_URL"].Str,
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		DocumentationURL: runner.Vars["DOCUMENTATION_URL"].Str,
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		SupportURL:       runner.Vars["SUPPORT_URL"].Str,
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		BugReportURL:     runner.Vars["BUG_REPORT_URL"].Str,
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		Logo:             runner.Vars["LOGO"].Str,
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	}
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	distroUpdated := false
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	if distID, ok := os.LookupEnv("ALR_DISTRO"); ok {
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		out.ID = distID
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	}
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	if distLike, ok := os.LookupEnv("ALR_DISTRO_LIKE"); ok {
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		out.Like = strings.Split(distLike, " ")
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	} else if runner.Vars["ID_LIKE"].IsSet() && !distroUpdated {
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		out.Like = strings.Split(runner.Vars["ID_LIKE"].Str, " ")
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	}
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	parsed = out
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	return out, nil
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}
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