-
Notifications
You must be signed in to change notification settings - Fork 4
/
kernel.go
214 lines (185 loc) · 5.98 KB
/
kernel.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
// This file is part of nullboot
// Copyright 2021 Canonical Ltd.
// SPDX-License-Identifier: GPL-3.0-only
package efibootmgr
import (
"fmt"
"io/ioutil"
"log"
"path"
"sort"
"strings"
"github.com/knqyf263/go-deb-version"
)
// KernelManager manages kernels in an SP vendor directory.
//
// It will update or install shim, copy in any new kernels,
// remove old kernels, and configure boot in shim and BDS.
type KernelManager struct {
sourceDir string // sourceDir is the location to copy kernels from
targetDir string // targetDir is a vendor directory on the ESP
sourceKernels []string // kernels in sourceDir
targetKernels []string // kernels in targetDir
bootEntries []BootEntry // boot entries filled by InstallKernels
kernelOptions string // options to pass to kernel
bootManager *BootManager // The EFI boot manager
}
// NewKernelManager returns a new kernel manager managing kernels in the host system
func NewKernelManager(esp, sourceDir, vendor string, bootManager *BootManager) (*KernelManager, error) {
var km KernelManager
var err error
km.sourceDir = sourceDir
km.targetDir = path.Join(esp, "EFI", vendor)
km.bootManager = bootManager
if file, err := appFs.Open("/etc/kernel/cmdline"); err == nil {
defer file.Close()
data, err := ioutil.ReadAll(file)
if err != nil {
return nil, fmt.Errorf("Cannot read kernel command line: %w", err)
}
km.kernelOptions = strings.TrimSpace(string(data))
}
km.sourceKernels, err = km.readKernels(km.sourceDir)
if err != nil {
return nil, err
}
km.targetKernels, err = km.readKernels(km.targetDir)
if err != nil {
return nil, err
}
return &km, nil
}
// readKernels returns a list of all kernels in the
func (km *KernelManager) readKernels(dir string) ([]string, error) {
var kernels []string
entries, err := appFs.ReadDir(dir)
if err != nil {
return nil, fmt.Errorf("Could not determine kernels: %w", err)
}
for _, e := range entries {
if strings.HasPrefix(e.Name(), "kernel.efi-") {
kernels = append(kernels, e.Name())
}
}
// Sort descending
sort.Slice(kernels, func(i, j int) bool {
a, e := version.NewVersion(kernels[i][len("kernel.efi-"):])
if e != nil {
err = fmt.Errorf("Could not parse kernel version of %s: %w", kernels[i], e)
return false
}
b, e := version.NewVersion(kernels[j][len("kernel.efi-"):])
if e != nil {
err = fmt.Errorf("Could not parse kernel version of %s: %w", kernels[j], e)
return false
}
return a.GreaterThan(b)
})
return kernels, err
}
// getKernelABI returns the kernel ABI part of the kernel filename
func getKernelABI(kernel string) string {
return kernel[len("kernel.efi-"):]
}
// InstallKernels installs the kernels to the ESP and builds up the boot entries
// to commit using CommitToBootLoader()
func (km *KernelManager) InstallKernels() error {
km.bootEntries = nil
for _, sk := range km.sourceKernels {
updated, err := MaybeUpdateFile(path.Join(km.targetDir, sk),
path.Join(km.sourceDir, sk))
if err != nil {
log.Printf("Could not install kernel %s: %v", sk, err)
continue
}
if updated {
log.Printf("Installed or updated kernel %s", sk)
}
// It is worth pointing out that the argument for shim should start with \
// which here somehow denotes it is in the same directory rather than the root.
// FIXME: Extract vendor name out into config file
skVersion := getKernelABI(sk)
options := "\\" + sk
if km.kernelOptions != "" {
options += " " + km.kernelOptions
}
km.bootEntries = append(km.bootEntries, BootEntry{
Filename: "shim" + GetEfiArchitecture() + ".efi",
Label: fmt.Sprintf("Ubuntu with kernel %s", skVersion),
Options: options,
Description: fmt.Sprintf("Ubuntu entry for kernel %s", skVersion),
})
}
return nil
}
// IsObsoleteKernel checks whether a kernel is obsolete.
func (km *KernelManager) isObsoleteKernel(k string) bool {
for _, sk := range km.sourceKernels {
if sk == k {
return false
}
}
return true
}
// RemoveObsoleteKernels removes old kernels in the ESP vendor directory
func (km *KernelManager) RemoveObsoleteKernels() error {
var remaining []string
for _, tk := range km.targetKernels {
if !km.isObsoleteKernel(tk) {
continue
}
if err := appFs.Remove(path.Join(km.targetDir, tk)); err != nil {
log.Printf("Could not remove kernel %s: %v", tk, err)
remaining = append(remaining, tk)
continue
}
log.Printf("Removed kernel %s", tk)
}
km.targetKernels = remaining
return nil
}
// CommitToBootLoader updates the firmware BDS entries and shim's boot.csv
func (km *KernelManager) CommitToBootLoader() error {
log.Print("Configuring shim fallback loader")
// We completely own the shim fallback file, so just write it
if err := WriteShimFallbackToFile(path.Join(km.targetDir, "BOOT"+strings.ToUpper(GetEfiArchitecture())+".CSV"), km.bootEntries); err != nil {
log.Printf("Failed to configure shim fallback loader: %v", err)
}
if km.bootManager == nil {
return nil
}
log.Print("Configuring UEFI boot device selection")
// This will become the head of the new boot order
var ourBootOrder []int
// Add new entries, find existing ones and build target boot order
for _, entry := range km.bootEntries {
bootNum, err := km.bootManager.FindOrCreateEntry(entry, km.targetDir)
if err != nil {
return fmt.Errorf("Failure to add boot entry for %s: %w", entry.Label, err)
}
ourBootOrder = append(ourBootOrder, bootNum)
}
// Delete any obsolete kernels
for _, ev := range km.bootManager.entries {
if !strings.HasPrefix(ev.LoadOption.Description, "Ubuntu ") {
continue
}
isObsolete := true
for _, num := range ourBootOrder {
if num == ev.BootNumber {
isObsolete = false
}
}
if !isObsolete {
continue
}
if err := km.bootManager.DeleteEntry(ev.BootNumber); err != nil {
log.Printf("Could not delete Boot%04X: %v", ev.BootNumber, err)
}
}
// Set the boot order
if err := km.bootManager.PrependAndSetBootOrder(ourBootOrder); err != nil {
return fmt.Errorf("Could not set boot order: %w", err)
}
return nil
}