pkg/v1/chroot

EnterChroot function

EnterChroot enters a chroot and changes the current working directory

to the new root. It returns a function that exits the chroot and

changes the current working directory to the old root. Remember to

call this function after you are done with the chroot to avoid

leaving the process in a chroot.

Example:

fExit, err := chroot.EnterChroot("/path/to/new/root")
if err != nil {
	fmt.Printf("Error entering chroot root: %v\n", err)
	if fExit != nil {
		fExit()
	}
	return
}
defer fExit()

Parameters:

• rootFs string

Returns:

• f func() error
• err error

{
	fd, err := os.Open("/")
	if err != nil {
		return nil, err
	}

	closeFunc := func() error {
		defer fd.Close()
		if err := fd.Chdir(); err != nil {
			return err
		}
		return syscall.Chroot(".")
	}

	err = syscall.Chroot(rootFs)
	if err != nil {
		return closeFunc, err
	}

	err = os.Chdir("/")
	if err != nil {
		return closeFunc, err
	}

	return closeFunc, nil
}

RunChroot function

RunChroot runs a function in a chroot and changes the current working

environment to the new root. It exits the chroot after the function

returns. The function returns the error returned by the function and

the error returned by ExitChroot if any.

Example:

err := chroot.RunChroot("/path/to/new/root", func() error {
	return exec.Command("ls", "-l").Run()
})
if err != nil {
	fmt.Printf("Error running command in chroot root: %v\n", err)
	return
}

Parameters:

• rootFs string
• f func() error

Returns:

• fErr error
• err error

{
	fd, err := os.Open("/")
	if err != nil {
		return nil, err
	}

	err = syscall.Chroot(rootFs)
	if err != nil {
		fd.Close()
		return nil, err
	}

	err = os.Chdir("/")
	if err != nil {
		fd.Close()
		err = syscall.Chroot(".")
		return nil, err
	}

	fErr = f()

	fd.Chdir()
	fd.Close()

	return fErr, syscall.Chroot(".")
}

EnterPivot function

EnterPivot enters a pivot and changes the current working directory

to the new root. It returns a function that exits the pivot and

changes the current working directory to the old root. Remember to

call this function after you are done with the pivot to avoid

leaving the process in a pivot.

Example:

fExit, err := chroot.EnterPivot("/path/to/new/root")
if err != nil {
	fmt.Printf("Error entering pivot root: %v\n", err)
	if fExit != nil {
		fExit()
	}
	return
}
defer fExit()

Parameters:

• rootFs string

Returns:

• f func() error
• err error

{
	fd, err := os.Open("/")
	if err != nil {
		return nil, err
	}

	closeFunc := func() error {
		defer fd.Close()
		if err := fd.Chdir(); err != nil {
			return err
		}
		return syscall.PivotRoot(".", rootFs)
	}

	pivotDir := filepath.Join(rootFs, ".pivot_root")
	err = os.MkdirAll(pivotDir, 0755)
	if err != nil {
		return closeFunc, err
	}

	err = syscall.PivotRoot(rootFs, pivotDir)
	if err != nil {
		return closeFunc, err
	}

	err = os.Chdir("/")
	if err != nil {
		return closeFunc, err
	}

	return closeFunc, nil
}

RunPivot function

RunPivot runs a function in a pivot and changes the current working

environment to the new root. It exits the pivot after the function

returns. The function returns the error returned by the function and

the error returned by ExitPivot if any.

Example:

err := chroot.RunPivot("/path/to/new/root", func() error {
	return exec.Command("ls", "-l").Run()
})

Parameters:

• rootFs string
• f func() error

Returns:

• error

{
	fExit, err := EnterPivot(rootFs)
	if err != nil {
		return err
	}
	defer fExit()

	return f()
}

ExitPivot function

ExitPivot exits the pivot and changes the current working directory

to the old root. It returns an error if any.

Example:

err := chroot.ExitPivot()

Returns:

• error

{
	return syscall.PivotRoot(".", ".")
}

os import

Import example:

import "os"

syscall import

Import example:

import "syscall"

os import

Import example:

import "os"

path/filepath import

Import example:

import "path/filepath"

syscall import

Import example:

import "syscall"