container: enforce nonrepeatable autoetc and autoroot

These keep track of some internal state, and they don't make sense to have multiple instances of anyway, so instead of dealing with that, just make them nonrepetable.

Signed-off-by: Ophestra <cat@gensokyo.uk>

3 files changed, 18 insertions, 1 deletions

diff --git a/container/autoetc.go b/container/autoetc.go
index f494d75c..23b1a86c 100644
--- a/container/autoetc.go
+++ b/container/autoetc.go
@@ -4,6 +4,7 @@ import (
 	"encoding/gob"
 	"fmt"
 	"os"
+	"syscall"
 )
 
 func init() { gob.Register(new(AutoEtcOp)) }
@@ -21,7 +22,12 @@ func (f *Ops) Etc(host *Absolute, prefix string) *Ops {
 type AutoEtcOp struct{ Prefix string }
 
 func (e *AutoEtcOp) early(*setupState) error { return nil }
-func (e *AutoEtcOp) apply(*setupState) error {
+func (e *AutoEtcOp) apply(state *setupState) error {
+	if state.nonrepeatable&nrAutoEtc != 0 {
+		return msg.WrapErr(syscall.EINVAL, "autoetc is not repeatable")
+	}
+	state.nonrepeatable |= nrAutoEtc
+
 	const target = sysrootPath + FHSEtc
 	rel := e.hostRel() + "/"
 
diff --git a/container/autoroot.go b/container/autoroot.go
index b155145c..215a7bb3 100644
--- a/container/autoroot.go
+++ b/container/autoroot.go
@@ -56,6 +56,11 @@ func (r *AutoRootOp) early(state *setupState) error {
 }
 
 func (r *AutoRootOp) apply(state *setupState) error {
+	if state.nonrepeatable&nrAutoRoot != 0 {
+		return msg.WrapErr(syscall.EINVAL, "autoroot is not repeatable")
+	}
+	state.nonrepeatable |= nrAutoRoot
+
 	for _, op := range r.resolved {
 		msg.Verbosef("%s %s", op.prefix(), op)
 		if err := op.apply(state); err != nil {
diff --git a/container/ops.go b/container/ops.go
index efc925b3..a08a12ff 100644
--- a/container/ops.go
+++ b/container/ops.go
@@ -24,6 +24,11 @@ const (
 	intermediatePatternTmpfile = "tmp.*"
 )
 
+const (
+	nrAutoEtc = 1 << iota
+	nrAutoRoot
+)
+
 type (
 	Ops []Op
 
@@ -41,6 +46,7 @@ type (
 	}
 
 	setupState struct {
+		nonrepeatable uintptr
 		*Params
 	}
 )