155 lines
2.9 KiB
Go
155 lines
2.9 KiB
Go
package main
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import (
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"fmt"
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"io"
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"log"
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"os"
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"os/exec"
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"runtime"
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"syscall"
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"time"
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"golang.org/x/term"
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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 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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layerMountFlags = syscall.MS_RDONLY
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)
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var (
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bootVersion string
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)
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func main() {
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runtime.LockOSThread()
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log.Print("Welcome to ", VERSION)
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// essential mounts
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mount("none", "/proc", "proc", 0, "")
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mount("none", "/sys", "sysfs", 0, "")
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mount("none", "/dev", "devtmpfs", 0, "")
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// get the "boot version"
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bootVersion = param("version", "current")
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log.Printf("booting system %q", bootVersion)
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_, err := os.Stat("/config.yaml")
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if err != nil {
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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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fatal("stat failed: ", err)
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}
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bootV2()
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}
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func layerPath(name string) string {
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return fmt.Sprintf("/boot/%s/layers/%s.fs", bootVersion, name)
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}
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func fatal(v ...interface{}) {
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log.Print("*** FATAL ***")
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log.Print(v...)
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die()
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}
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func fatalf(pattern string, v ...interface{}) {
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log.Print("*** FATAL ***")
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log.Printf(pattern, v...)
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die()
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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, s to get a shell")
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deadline := time.Now().Add(time.Minute)
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term.MakeRaw(int(os.Stdin.Fd())) // disable line buffering
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os.Stdin.SetReadDeadline(deadline)
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b := []byte{0}
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for {
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_, err := os.Stdin.Read(b)
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if err != nil {
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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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syscall.Reboot(syscall.LINUX_REBOOT_CMD_RESTART)
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}
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func losetup(dev, file string) {
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run("/sbin/losetup", dev, file)
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}
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func run(cmd string, args ...string) {
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if output, err := exec.Command(cmd, args...).CombinedOutput(); err != nil {
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fatalf("command %s %q failed: %v\n%s", cmd, args, err, string(output))
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}
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}
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func mkdir(dir string, mode os.FileMode) {
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if err := os.MkdirAll(dir, mode); err != nil {
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fatalf("mkdir %q failed: %v", dir, err)
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}
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}
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func mount(source, target, fstype string, flags uintptr, data string) {
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if _, err := os.Stat(target); os.IsNotExist(err) {
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mkdir(target, 0755)
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}
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if err := syscall.Mount(source, target, fstype, flags, data); err != nil {
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fatalf("mount %q %q -t %q -o %q failed: %v", source, target, fstype, data, err)
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}
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log.Printf("mounted %q", target)
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}
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func cp(srcPath, dstPath string) {
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var err error
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defer func() {
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if err != nil {
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fatalf("cp %s %s failed: %v", srcPath, dstPath, err)
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}
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}()
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src, err := os.Open(srcPath)
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if err != nil {
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return
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}
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defer src.Close()
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dst, err := os.Create(dstPath)
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if err != nil {
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return
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}
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defer dst.Close()
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_, err = io.Copy(dst, src)
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}
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