mirror of
https://github.com/mudler/luet.git
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95 lines
2.3 KiB
Go
95 lines
2.3 KiB
Go
// Copyright © 2020 Ettore Di Giacinto <mudler@gentoo.org>
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with this program; if not, see <http://www.gnu.org/licenses/>.
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package box
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import (
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"os"
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"path/filepath"
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"syscall"
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)
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func PivotRoot(newroot string) error {
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putold := filepath.Join(newroot, "/.pivot_root")
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// bind mount newroot to itself - this is a slight hack needed to satisfy the
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// pivot_root requirement that newroot and putold must not be on the same
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// filesystem as the current root
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if err := syscall.Mount(newroot, newroot, "", syscall.MS_BIND|syscall.MS_REC, ""); err != nil {
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return err
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}
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// create putold directory
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if err := os.MkdirAll(putold, 0700); err != nil {
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return err
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}
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// call pivot_root
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if err := syscall.PivotRoot(newroot, putold); err != nil {
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return err
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}
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// ensure current working directory is set to new root
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if err := os.Chdir("/"); err != nil {
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return err
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}
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// umount putold, which now lives at /.pivot_root
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putold = "/.pivot_root"
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if err := syscall.Unmount(putold, syscall.MNT_DETACH); err != nil {
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return err
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}
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// remove putold
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if err := os.RemoveAll(putold); err != nil {
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return err
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}
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return nil
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}
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func mountProc(newroot string) error {
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source := "proc"
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target := filepath.Join(newroot, "/proc")
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fstype := "proc"
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flags := 0
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data := ""
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os.MkdirAll(target, 0755)
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if err := syscall.Mount(source, target, fstype, uintptr(flags), data); err != nil {
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return err
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}
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return nil
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}
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func mountBind(hostfolder, newroot, dst string) error {
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source := hostfolder
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target := filepath.Join(newroot, dst)
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fstype := "bind"
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data := ""
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os.MkdirAll(target, 0755)
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if err := syscall.Mount(source, target, fstype, syscall.MS_BIND|syscall.MS_REC, data); err != nil {
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return err
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}
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return nil
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}
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func mountDev(newroot string) error {
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return mountBind("/dev", newroot, "/dev")
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}
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