diff --git a/chrootarchive/archive.go b/chrootarchive/archive.go new file mode 100644 index 0000000..f1df57c --- /dev/null +++ b/chrootarchive/archive.go @@ -0,0 +1,76 @@ +package chrootarchive + +import ( + "flag" + "fmt" + "io" + "os" + "runtime" + "syscall" + + "github.com/docker/docker/pkg/archive" + "github.com/docker/docker/pkg/reexec" +) + +func untar() { + runtime.LockOSThread() + flag.Parse() + + if err := syscall.Chroot(flag.Arg(0)); err != nil { + fatal(err) + } + if err := syscall.Chdir("/"); err != nil { + fatal(err) + } + if err := archive.Untar(os.Stdin, "/", nil); err != nil { + fatal(err) + } + os.Exit(0) +} + +var ( + chrootArchiver = &archive.Archiver{Untar} +) + +func Untar(archive io.Reader, dest string, options *archive.TarOptions) error { + if _, err := os.Stat(dest); os.IsNotExist(err) { + if err := os.MkdirAll(dest, 0777); err != nil { + return err + } + } + cmd := reexec.Command("docker-untar", dest) + cmd.Stdin = archive + out, err := cmd.CombinedOutput() + if err != nil { + return fmt.Errorf("Untar %s %s", err, out) + } + return nil +} + +func TarUntar(src, dst string) error { + return chrootArchiver.TarUntar(src, dst) +} + +// CopyWithTar creates a tar archive of filesystem path `src`, and +// unpacks it at filesystem path `dst`. +// The archive is streamed directly with fixed buffering and no +// intermediary disk IO. +func CopyWithTar(src, dst string) error { + return chrootArchiver.CopyWithTar(src, dst) +} + +// CopyFileWithTar emulates the behavior of the 'cp' command-line +// for a single file. It copies a regular file from path `src` to +// path `dst`, and preserves all its metadata. +// +// If `dst` ends with a trailing slash '/', the final destination path +// will be `dst/base(src)`. +func CopyFileWithTar(src, dst string) (err error) { + return chrootArchiver.CopyFileWithTar(src, dst) +} + +// UntarPath is a convenience function which looks for an archive +// at filesystem path `src`, and unpacks it at `dst`. +func UntarPath(src, dst string) error { + return chrootArchiver.UntarPath(src, dst) +} diff --git a/chrootarchive/diff.go b/chrootarchive/diff.go new file mode 100644 index 0000000..2133200 --- /dev/null +++ b/chrootarchive/diff.go @@ -0,0 +1,38 @@ +package chrootarchive + +import ( + "flag" + "fmt" + "os" + "runtime" + "syscall" + + "github.com/docker/docker/pkg/archive" + "github.com/docker/docker/pkg/reexec" +) + +func applyLayer() { + runtime.LockOSThread() + flag.Parse() + + if err := syscall.Chroot(flag.Arg(0)); err != nil { + fatal(err) + } + if err := syscall.Chdir("/"); err != nil { + fatal(err) + } + if err := archive.ApplyLayer("/", os.Stdin); err != nil { + fatal(err) + } + os.Exit(0) +} + +func ApplyLayer(dest string, layer archive.ArchiveReader) error { + cmd := reexec.Command("docker-applyLayer", dest) + cmd.Stdin = layer + out, err := cmd.CombinedOutput() + if err != nil { + return fmt.Errorf("ApplyLayer %s %s", err, out) + } + return nil +} diff --git a/chrootarchive/init.go b/chrootarchive/init.go new file mode 100644 index 0000000..b548e9f --- /dev/null +++ b/chrootarchive/init.go @@ -0,0 +1,18 @@ +package chrootarchive + +import ( + "fmt" + "os" + + "github.com/docker/docker/pkg/reexec" +) + +func init() { + reexec.Register("docker-untar", untar) + reexec.Register("docker-applyLayer", applyLayer) +} + +func fatal(err error) { + fmt.Fprint(os.Stderr, err) + os.Exit(1) +} diff --git a/reexec/command_linux.go b/reexec/command_linux.go new file mode 100644 index 0000000..8dc3f3a --- /dev/null +++ b/reexec/command_linux.go @@ -0,0 +1,18 @@ +// +build linux + +package reexec + +import ( + "os/exec" + "syscall" +) + +func Command(args ...string) *exec.Cmd { + return &exec.Cmd{ + Path: Self(), + Args: args, + SysProcAttr: &syscall.SysProcAttr{ + Pdeathsig: syscall.SIGTERM, + }, + } +} diff --git a/reexec/command_unsupported.go b/reexec/command_unsupported.go new file mode 100644 index 0000000..a579318 --- /dev/null +++ b/reexec/command_unsupported.go @@ -0,0 +1,11 @@ +// +build !linux + +package reexec + +import ( + "os/exec" +) + +func Command(args ...string) *exec.Cmd { + return nil +} diff --git a/reexec/reexec.go b/reexec/reexec.go index 136b905..774e71c 100644 --- a/reexec/reexec.go +++ b/reexec/reexec.go @@ -27,19 +27,16 @@ func Init() bool { return true } - return false } // Self returns the path to the current processes binary func Self() string { name := os.Args[0] - if filepath.Base(name) == name { if lp, err := exec.LookPath(name); err == nil { name = lp } } - return name }