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init+dhcp changes for Squashfs root file systems

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We can do away with a bunch of hacks now, but we’ll keep them around for a
little while to make updates easier (i.e. to boot with old and new gokr-packer
versions, just in case people don’t update both at the same time).
This commit is contained in:
Michael Stapelberg 2018-06-21 23:21:51 +02:00
parent d1d355d840
commit 4a126f13af
3 changed files with 37 additions and 12 deletions
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8
cmd/dhcp/dhcp.go
View File

@ -235,8 +235,12 @@ func main() {
}
if b, ok := opts[dhcp4.OptionDomainNameServer]; ok {
resolvConf := "/etc/resolv.conf"
if dest, err := os.Readlink("/etc/resolv.conf"); err == nil && dest == "/tmp/resolv.conf" {
resolvConf = "/tmp/resolv.conf"
}
// Get the symlink out of the way, if any.
if err := os.Remove("/etc/resolv.conf"); err != nil && !os.IsNotExist(err) {
if err := os.Remove(resolvConf); err != nil && !os.IsNotExist(err) {
log.Fatalf("resolv.conf: %v", err)
}
var lines []string
@ -245,7 +249,7 @@ func main() {
lines = append(lines, fmt.Sprintf("search %s", string(domain)))
}
lines = append(lines, fmt.Sprintf("nameserver %v", net.IP(b)))
if err := ioutil.WriteFile("/etc/resolv.conf", []byte(strings.Join(lines, "\n")+"\n"), 0644); err != nil {
if err := ioutil.WriteFile(resolvConf, []byte(strings.Join(lines, "\n")+"\n"), 0644); err != nil {
log.Fatalf("resolv.conf: %v", err)
}
}

16
gokrazy.go
View File

@ -68,7 +68,7 @@ func watchdog() {
//
// - mounts /dev, /tmp, /proc, /sys and /perm file systems
// - mounts and populate /etc tmpfs overlay
// - sets hostname from the /hostname file
// - sets hostname from the /etc/hostname file
// - sets HTTP password from the gokr-pw.txt file
// - configures the loopback network interface
//
@ -87,7 +87,10 @@ func Boot(userBuildTimestamp string) error {
return err
}
hostnameb, err := ioutil.ReadFile("/hostname")
hostnameb, err := ioutil.ReadFile("/etc/hostname")
if err != nil && os.IsNotExist(err) {
hostnameb, err = ioutil.ReadFile("/hostname")
}
if err != nil {
return err
}
@ -98,10 +101,13 @@ func Boot(userBuildTimestamp string) error {
pw, err := ioutil.ReadFile("/perm/gokr-pw.txt")
if err != nil {
pw, err = ioutil.ReadFile("/gokr-pw.txt")
if err != nil {
return fmt.Errorf("could read neither /perm/gokr-pw.txt nor /gokr-pw.txt: %v", err)
pw, err = ioutil.ReadFile("/etc/gokr-pw.txt")
}
if err != nil && os.IsNotExist(err) {
pw, err = ioutil.ReadFile("/gokr-pw.txt")
}
if err != nil {
return fmt.Errorf("could read neither /perm/gokr-pw.txt, nor /etc/gokr-pw.txt, nor /gokr-pw.txt: %v", err)
}
httpPassword = strings.TrimSpace(string(pw))

25
mount.go
View File

@ -8,11 +8,9 @@ import (
"syscall"
)
func mountfs() error {
if err := syscall.Mount("tmpfs", "/tmp", "tmpfs", syscall.MS_NOSUID|syscall.MS_NODEV|syscall.MS_RELATIME, "size=50M"); err != nil {
return fmt.Errorf("tmpfs on /tmp: %v", err)
}
// mountCompat deals with old FAT root file systems, to cover the case where
// users use an old gokr-packer with a new github.com/gokrazy/gokrazy package.
func mountCompat() error {
// Symlink /etc/resolv.conf. We cannot do this in the root file
// system itself, as FAT does not support symlinks.
if err := syscall.Mount("tmpfs", "/etc", "tmpfs", syscall.MS_NOSUID|syscall.MS_NODEV|syscall.MS_RELATIME, "size=1M"); err != nil {
@ -40,6 +38,23 @@ func mountfs() error {
if err := ioutil.WriteFile("/etc/hosts", []byte("127.0.0.1 localhost\n::1 localhost\n"), 0644); err != nil {
return fmt.Errorf("/etc/hosts: %v", err)
}
return nil
}
func mountfs() error {
if err := syscall.Mount("tmpfs", "/tmp", "tmpfs", syscall.MS_NOSUID|syscall.MS_NODEV|syscall.MS_RELATIME, "size=50M"); err != nil {
return fmt.Errorf("tmpfs on /tmp: %v", err)
}
if err := os.Symlink("/proc/net/pnp", "/tmp/resolv.conf"); err != nil {
return fmt.Errorf("etc: %v", err)
}
if _, err := os.Lstat("/etc/resolv.conf"); err != nil && os.IsNotExist(err) {
if err := mountCompat(); err != nil {
return err
}
}
if err := syscall.Mount("devtmpfs", "/dev", "devtmpfs", 0, ""); err != nil {
if sce, ok := err.(syscall.Errno); ok && sce == syscall.EBUSY {