ALR

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package handlers
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import (
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	"context"
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	"fmt"
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	"os"
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	"os/exec"
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	"runtime"
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	"strings"
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	"syscall"
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	"time"
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	"plemya-x.ru/fakeroot"
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	"mvdan.cc/sh/v3/expand"
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	"mvdan.cc/sh/v3/interp"
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)
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// FakerootExecHandler was extracted from github.com/mvdan/sh/interp/handler.go
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// and modified to run commands in a fakeroot environent.
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func FakerootExecHandler(killTimeout time.Duration) interp.ExecHandlerFunc {
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	return func(ctx context.Context, args []string) error {
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		hc := interp.HandlerCtx(ctx)
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		path, err := interp.LookPathDir(hc.Dir, hc.Env, args[0])
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		if err != nil {
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			fmt.Fprintln(hc.Stderr, err)
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			return interp.NewExitStatus(127)
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		}
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		cmd := &exec.Cmd{
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			Path:   path,
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			Args:   args,
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			Env:    execEnv(hc.Env),
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			Dir:    hc.Dir,
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			Stdin:  hc.Stdin,
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			Stdout: hc.Stdout,
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			Stderr: hc.Stderr,
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		}
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		err = fakeroot.Apply(cmd)
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		if err != nil {
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			return err
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		}
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		err = cmd.Start()
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		if err == nil {
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			if done := ctx.Done(); done != nil {
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				go func() {
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					<-done
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					if killTimeout <= 0 || runtime.GOOS == "windows" {
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						_ = cmd.Process.Signal(os.Kill)
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						return
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					}
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					// TODO: don't temporarily leak this goroutine
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					// if the program stops itself with the
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					// interrupt.
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					go func() {
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						time.Sleep(killTimeout)
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						_ = cmd.Process.Signal(os.Kill)
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					}()
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					_ = cmd.Process.Signal(os.Interrupt)
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				}()
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			}
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			err = cmd.Wait()
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		}
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		switch x := err.(type) {
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		case *exec.ExitError:
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			// started, but errored - default to 1 if OS
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			// doesn't have exit statuses
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			if status, ok := x.Sys().(syscall.WaitStatus); ok {
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				if status.Signaled() {
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					if ctx.Err() != nil {
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						return ctx.Err()
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					}
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					return interp.NewExitStatus(uint8(128 + status.Signal()))
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				}
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				return interp.NewExitStatus(uint8(status.ExitStatus()))
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			}
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			return interp.NewExitStatus(1)
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		case *exec.Error:
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			// did not start
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			fmt.Fprintf(hc.Stderr, "%v\n", err)
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			return interp.NewExitStatus(127)
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		default:
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			return err
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		}
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	}
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}
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// execEnv was extracted from github.com/mvdan/sh/interp/vars.go
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func execEnv(env expand.Environ) []string {
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	list := make([]string, 0, 64)
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	env.Each(func(name string, vr expand.Variable) bool {
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		if !vr.IsSet() {
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			// If a variable is set globally but unset in the
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			// runner, we need to ensure it's not part of the final
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			// list. Seems like zeroing the element is enough.
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			// This is a linear search, but this scenario should be
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			// rare, and the number of variables shouldn't be large.
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			for i, kv := range list {
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				if strings.HasPrefix(kv, name+"=") {
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					list[i] = ""
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				}
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			}
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		}
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		if vr.Exported && vr.Kind == expand.String {
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			list = append(list, name+"="+vr.String())
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		}
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		return true
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	})
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	return list
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}
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