prepare boot v2
This commit is contained in:
Mikaël Cluseau
147
main.go
147
main.go
@ -3,24 +3,19 @@ package main
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import (
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"os"
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"os/exec"
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"path/filepath"
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"runtime"
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"strings"
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"syscall"
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"time"
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"golang.org/x/term"
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yaml "gopkg.in/yaml.v2"
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"novit.nc/direktil/pkg/sysfs"
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)
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const (
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// VERSION is the current version of init
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VERSION = "Direktil init v1.0"
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VERSION = "Direktil init v2.0"
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rootMountFlags = 0
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bootMountFlags = syscall.MS_NOEXEC | syscall.MS_NODEV | syscall.MS_NOSUID | syscall.MS_RDONLY
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@ -45,135 +40,16 @@ func main() {
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bootVersion = param("version", "current")
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log.Printf("booting system %q", bootVersion)
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// find and mount /boot
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bootMatch := param("boot", "")
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bootMounted := false
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if bootMatch != "" {
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bootFS := param("boot.fs", "vfat")
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for i := 0; ; i++ {
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devNames := sysfs.DeviceByProperty("block", bootMatch)
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if len(devNames) == 0 {
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if i > 30 {
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fatal("boot partition not found after 30s")
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}
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log.Print("boot partition not found, retrying")
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time.Sleep(1 * time.Second)
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continue
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}
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devFile := filepath.Join("/dev", devNames[0])
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log.Print("boot partition found: ", devFile)
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mount(devFile, "/boot", bootFS, bootMountFlags, "")
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bootMounted = true
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break
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}
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} else {
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log.Print("Assuming /boot is already populated.")
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}
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// load config
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cfgPath := param("config", "/boot/config.yaml")
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cfgBytes, err := ioutil.ReadFile(cfgPath)
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_, err := os.Stat("/config.yaml")
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if err != nil {
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fatalf("failed to read %s: %v", cfgPath, err)
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}
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cfg := &config{}
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if err := yaml.Unmarshal(cfgBytes, cfg); err != nil {
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fatal("failed to load config: ", err)
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}
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// mount layers
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if len(cfg.Layers) == 0 {
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fatal("no layers configured!")
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}
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log.Printf("wanted layers: %q", cfg.Layers)
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layersInMemory := paramBool("layers-in-mem", false)
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const layersInMemDir = "/layers-in-mem"
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if layersInMemory {
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mkdir(layersInMemDir, 0700)
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mount("layers-mem", layersInMemDir, "tmpfs", 0, "")
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}
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lowers := make([]string, len(cfg.Layers))
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for i, layer := range cfg.Layers {
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path := layerPath(layer)
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info, err := os.Stat(path)
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if err != nil {
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fatal(err)
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if os.IsNotExist(err) {
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bootV1()
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return
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}
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log.Printf("layer %s found (%d bytes)", layer, info.Size())
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if layersInMemory {
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log.Print(" copying to memory...")
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targetPath := filepath.Join(layersInMemDir, layer)
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cp(path, targetPath)
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path = targetPath
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}
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dir := "/layers/" + layer
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lowers[i] = dir
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loopDev := fmt.Sprintf("/dev/loop%d", i)
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losetup(loopDev, path)
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mount(loopDev, dir, "squashfs", layerMountFlags, "")
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fatal("stat failed: ", err)
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}
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// prepare system root
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mount("mem", "/changes", "tmpfs", 0, "")
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mkdir("/changes/workdir", 0755)
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mkdir("/changes/upperdir", 0755)
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mount("overlay", "/system", "overlay", rootMountFlags,
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"lowerdir="+strings.Join(lowers, ":")+",upperdir=/changes/upperdir,workdir=/changes/workdir")
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if bootMounted {
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if layersInMemory {
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if err := syscall.Unmount("/boot", 0); err != nil {
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log.Print("WARNING: failed to unmount /boot: ", err)
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time.Sleep(2 * time.Second)
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}
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} else {
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mount("/boot", "/system/boot", "", syscall.MS_BIND, "")
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}
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}
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// - write configuration
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log.Print("writing /config.yaml")
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if err := ioutil.WriteFile("/system/config.yaml", cfgBytes, 0600); err != nil {
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fatal("failed: ", err)
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}
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// - write files
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for _, fileDef := range cfg.Files {
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log.Print("writing ", fileDef.Path)
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filePath := filepath.Join("/system", fileDef.Path)
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ioutil.WriteFile(filePath, []byte(fileDef.Content), fileDef.Mode)
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}
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// clean zombies
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cleanZombies()
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// switch root
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log.Print("switching root")
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err = syscall.Exec("/sbin/switch_root", []string{"switch_root",
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"-c", "/dev/console", "/system", "/sbin/init"}, os.Environ())
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fatal("switch_root failed: ", err)
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bootV2()
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}
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func layerPath(name string) string {
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@ -193,7 +69,7 @@ func fatalf(pattern string, v ...interface{}) {
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}
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func die() {
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fmt.Println("\nwill reboot in 1 minute; press r to reboot now, o to power off")
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fmt.Println("\nwill reboot in 1 minute; press r to reboot now, o to power off, s to get a shell")
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deadline := time.Now().Add(time.Minute)
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@ -207,11 +83,18 @@ func die() {
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break
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}
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fmt.Println(string(b))
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switch b[0] {
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case 'o':
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syscall.Reboot(syscall.LINUX_REBOOT_CMD_POWER_OFF)
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case 'r':
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syscall.Reboot(syscall.LINUX_REBOOT_CMD_RESTART)
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case 's':
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err = syscall.Exec("/bin/ash", []string{"/bin/ash"}, os.Environ())
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if err != nil {
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fmt.Println("failed to start the shell:", err)
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}
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}
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}
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