1 files changed, 61 insertions, 0 deletions
diff --git a/container/initsymlink.go b/container/initsymlink.go
new file mode 100644
index 00000000..ae061694
--- /dev/null
+++ b/container/initsymlink.go
@@ -0,0 +1,61 @@
+package container
+
+import (
+	"encoding/gob"
+	"fmt"
+	"os"
+	"path"
+	"syscall"
+)
+
+func init() { gob.Register(new(SymlinkOp)) }
+
+// Link appends an [Op] that creates a symlink in the container filesystem.
+func (f *Ops) Link(target *Absolute, linkName string, dereference bool) *Ops {
+	*f = append(*f, &SymlinkOp{target, linkName, dereference})
+	return f
+}
+
+// SymlinkOp optionally dereferences LinkName and creates a symlink at container path Target.
+type SymlinkOp struct {
+	Target *Absolute
+	// LinkName is an arbitrary uninterpreted pathname.
+	LinkName string
+
+	// Dereference causes LinkName to be dereferenced during early.
+	Dereference bool
+}
+
+func (l *SymlinkOp) early(*setupState) error {
+	if l.Dereference {
+		if !isAbs(l.LinkName) {
+			return msg.WrapErr(syscall.EBADE, fmt.Sprintf("path %q is not absolute", l.LinkName))
+		}
+		if name, err := os.Readlink(l.LinkName); err != nil {
+			return wrapErrSelf(err)
+		} else {
+			l.LinkName = name
+		}
+	}
+	return nil
+}
+
+func (l *SymlinkOp) apply(state *setupState) error {
+	if l.Target == nil {
+		return syscall.EBADE
+	}
+	target := toSysroot(l.Target.String())
+	if err := os.MkdirAll(path.Dir(target), state.ParentPerm); err != nil {
+		return wrapErrSelf(err)
+	}
+	if err := os.Symlink(l.LinkName, target); err != nil {
+		return wrapErrSelf(err)
+	}
+	return nil
+}
+
+func (l *SymlinkOp) Is(op Op) bool { vl, ok := op.(*SymlinkOp); return ok && *l == *vl }
+func (*SymlinkOp) prefix() string  { return "creating" }
+func (l *SymlinkOp) String() string {
+	return fmt.Sprintf("symlink on %q linkname %q", l.Target, l.LinkName)
+}