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Switch to having the moby tool specify how to do mounts

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This removes all the code that had knowledge of how to do read only
and read write container mounts, and just uses the runtime config.

Signed-off-by: Justin Cormack <justin.cormack@docker.com>
This commit is contained in:
Justin Cormack 2017-08-22 16:23:20 +01:00
parent c677b391fc
commit 49cf74f4f6
1 changed files with 14 additions and 46 deletions
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60
pkg/init/cmd/service/prepare.go
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@ -66,7 +66,6 @@ func getRuntimeConfig(path string) Runtime {
// parseMountOptions takes fstab style mount options and parses them for
// use with a standard mount() syscall
// taken from containerd, where it is not exported
func parseMountOptions(options []string) (int, string) {
var (
flag int
@ -93,14 +92,18 @@ func parseMountOptions(options []string) (int, string) {
"norelatime": {true, unix.MS_RELATIME},
"nostrictatime": {true, unix.MS_STRICTATIME},
"nosuid": {false, unix.MS_NOSUID},
"private": {false, unix.MS_PRIVATE},
"rbind": {false, unix.MS_BIND | unix.MS_REC},
"relatime": {false, unix.MS_RELATIME},
"remount": {false, unix.MS_REMOUNT},
"ro": {false, unix.MS_RDONLY},
"rw": {true, unix.MS_RDONLY},
"shared": {false, unix.MS_SHARED},
"slave": {false, unix.MS_SLAVE},
"strictatime": {false, unix.MS_STRICTATIME},
"suid": {true, unix.MS_NOSUID},
"sync": {false, unix.MS_SYNCHRONOUS},
"unbindable": {false, unix.MS_UNBINDABLE},
}
for _, o := range options {
// If the option does not exist in the flags table or the flag
@ -130,6 +133,16 @@ func prepareFilesystem(path string, runtime Runtime) error {
if err != nil {
return fmt.Errorf("Cannot create directory for mount destination %s: %v", mount.Destination, err)
}
// also mkdir upper and work directories on overlay
for _, o := range mount.Options {
eq := strings.SplitN(o, "=", 2)
if len(eq) == 2 && (eq[0] == "upperdir" || eq[0] == "workdir") {
err := os.MkdirAll(eq[1], mode)
if err != nil {
return fmt.Errorf("Cannot create directory for overlay %s=%s: %v", eq[0], eq[1], err)
}
}
}
opts, data := parseMountOptions(mount.Options)
if err := unix.Mount(mount.Source, mount.Destination, mount.Type, uintptr(opts), data); err != nil {
return fmt.Errorf("Failed to mount %s: %v", mount.Source, err)
@ -144,51 +157,6 @@ func prepareFilesystem(path string, runtime Runtime) error {
}
}
// see if we are dealing with a read only or read write container
if _, err := os.Stat(filepath.Join(path, "lower")); err != nil {
if os.IsNotExist(err) {
return prepareRO(path)
}
return err
}
return prepareRW(path)
}
func prepareRO(path string) error {
// make rootfs a mount point, as runc doesn't like it much otherwise
rootfs := filepath.Join(path, "rootfs")
if err := unix.Mount(rootfs, rootfs, "", unix.MS_BIND, ""); err != nil {
return err
}
return nil
}
func prepareRW(path string) error {
// mount a tmpfs on tmp for upper and workdirs
// make it private as nothing else should be using this
tmp := filepath.Join(path, "tmp")
if err := unix.Mount("tmpfs", tmp, "tmpfs", 0, "size=10%"); err != nil {
return err
}
// make it private as nothing else should be using this
if err := unix.Mount("", tmp, "", unix.MS_REMOUNT|unix.MS_PRIVATE, ""); err != nil {
return err
}
upper := filepath.Join(tmp, "upper")
// make the mount points
if err := os.Mkdir(upper, 0755); err != nil {
return err
}
work := filepath.Join(tmp, "work")
if err := os.Mkdir(work, 0755); err != nil {
return err
}
lower := filepath.Join(path, "lower")
rootfs := filepath.Join(path, "rootfs")
opt := fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s", lower, upper, work)
if err := unix.Mount("overlay", rootfs, "overlay", 0, opt); err != nil {
return err
}
return nil
}