src/pkg/provisioner/sed_grub_config_step.go

// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package provisioner

import (
	"context"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"

	"cos.googlesource.com/cos/tools.git/src/pkg/tools/partutil"
)

type SedGrubConfigStep struct {
	SedScript string
}

func (s *SedGrubConfigStep) run(ctx context.Context, runState *state, deps *stepDeps) error {
	if s.SedScript == "" {
		log.Println("No sed script provided; not making any grub config changes")
		return nil
	}
	log.Printf("Running sed script %q on grub config", s.SedScript)
	efiPath, err := partutil.MountEFIPartition()
	if err != nil {
		return err
	}
	grubCfgPath := filepath.Join(efiPath, partutil.GRUBCfgEFIPath)
	cmd := exec.Command(deps.SedCmd, "-i", "-e", s.SedScript, grubCfgPath)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	if err := cmd.Run(); err != nil {
		umountErr := partutil.UnmountEFIPartition()
		if umountErr != nil {
			log.Printf("ERROR: failed to umount EFI partition: %v", umountErr)
		}
		return fmt.Errorf("could not sed grub config, see logs for details: %v", err)
	}
	return partutil.UnmountEFIPartition()
}