gokrazy/mount.go

108 lines
3.2 KiB
Go

package gokrazy
import (
"fmt"
"io/ioutil"
"log"
"os"
"syscall"
"github.com/gokrazy/internal/rootdev"
)
// 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 {
return fmt.Errorf("tmpfs on /etc: %v", err)
}
if err := os.Symlink("/proc/net/pnp", "/etc/resolv.conf"); err != nil {
return fmt.Errorf("etc: %v", err)
}
// Symlink /etc/localtime. We cannot do this in the root file
// system, as FAT filenames are limited to 8.3.
if err := os.Symlink("/localtim", "/etc/localtime"); err != nil {
return fmt.Errorf("etc: %v", err)
}
if err := os.Mkdir("/etc/ssl", 0755); err != nil {
return fmt.Errorf("/etc/ssl: %v", err)
}
if err := os.Symlink("/cacerts", "/etc/ssl/ca-bundle.pem"); err != nil {
return fmt.Errorf("/etc/ssl: %v", err)
}
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 {
// /dev was already mounted (common in setups using nfsroot= or initramfs)
} else {
return fmt.Errorf("devtmpfs: %v", err)
}
}
if err := os.MkdirAll("/dev/pts", 0755); err != nil {
return fmt.Errorf("mkdir /dev/pts: %v", err)
}
if err := syscall.Mount("devpts", "/dev/pts", "devpts", 0, ""); err != nil {
return fmt.Errorf("devpts: %v", err)
}
// /proc is useful for exposing process details and for
// interactive debugging sessions.
if err := syscall.Mount("proc", "/proc", "proc", 0, ""); err != nil {
if sce, ok := err.(syscall.Errno); ok && sce == syscall.EBUSY {
// /proc was already mounted (common in setups using nfsroot= or initramfs)
} else {
return fmt.Errorf("proc: %v", err)
}
}
// /sys is useful for retrieving additional status from the
// kernel, e.g. ethernet device carrier status.
if err := syscall.Mount("sysfs", "/sys", "sysfs", 0, ""); err != nil {
if sce, ok := err.(syscall.Errno); ok && sce == syscall.EBUSY {
// /sys was already mounted (common in setups using nfsroot= or initramfs)
} else {
return fmt.Errorf("sys: %v", err)
}
}
dev := rootdev.Partition(rootdev.Perm)
for _, fstype := range []string{"ext4", "vfat"} {
if err := syscall.Mount(dev, "/perm", fstype, 0, ""); err != nil {
log.Printf("Could not mount permanent storage partition %s as %s: %v", dev, fstype, err)
} else {
break
}
}
return nil
}