github.com/rigado/snapd@v2.42.5-go-mod+incompatible/bootloader/grub.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2014-2015 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package bootloader
    21  
    22  import (
    23  	"os"
    24  	"path/filepath"
    25  
    26  	"github.com/snapcore/snapd/bootloader/grubenv"
    27  	"github.com/snapcore/snapd/osutil"
    28  	"github.com/snapcore/snapd/snap"
    29  )
    30  
    31  type grub struct {
    32  	rootdir string
    33  }
    34  
    35  // newGrub create a new Grub bootloader object
    36  func newGrub(rootdir string) Bootloader {
    37  	g := &grub{rootdir: rootdir}
    38  	if !osutil.FileExists(g.ConfigFile()) {
    39  		return nil
    40  	}
    41  
    42  	return g
    43  }
    44  
    45  func (g *grub) Name() string {
    46  	return "grub"
    47  }
    48  
    49  func (g *grub) setRootDir(rootdir string) {
    50  	g.rootdir = rootdir
    51  }
    52  
    53  func (g *grub) dir() string {
    54  	if g.rootdir == "" {
    55  		panic("internal error: unset rootdir")
    56  	}
    57  	return filepath.Join(g.rootdir, "/boot/grub")
    58  }
    59  
    60  func (g *grub) ConfigFile() string {
    61  	return filepath.Join(g.dir(), "grub.cfg")
    62  }
    63  
    64  func (g *grub) envFile() string {
    65  	return filepath.Join(g.dir(), "grubenv")
    66  }
    67  
    68  func (g *grub) GetBootVars(names ...string) (map[string]string, error) {
    69  	out := make(map[string]string)
    70  
    71  	env := grubenv.NewEnv(g.envFile())
    72  	if err := env.Load(); err != nil {
    73  		return nil, err
    74  	}
    75  
    76  	for _, name := range names {
    77  		out[name] = env.Get(name)
    78  	}
    79  
    80  	return out, nil
    81  }
    82  
    83  func (g *grub) SetBootVars(values map[string]string) error {
    84  	env := grubenv.NewEnv(g.envFile())
    85  	if err := env.Load(); err != nil && !os.IsNotExist(err) {
    86  		return err
    87  	}
    88  	for k, v := range values {
    89  		env.Set(k, v)
    90  	}
    91  	return env.Save()
    92  }
    93  
    94  func (g *grub) ExtractKernelAssets(s snap.PlaceInfo, snapf snap.Container) error {
    95  	// XXX: should we use "kernel.yaml" for this?
    96  	if _, err := snapf.ReadFile("meta/force-kernel-extraction"); err == nil {
    97  		return extractKernelAssetsToBootDir(g.dir(), s, snapf)
    98  	}
    99  	return nil
   100  }
   101  
   102  func (g *grub) RemoveKernelAssets(s snap.PlaceInfo) error {
   103  	return removeKernelAssetsFromBootDir(g.dir(), s)
   104  }