internal/rosa: static etc artifact

This places configuration files with hardcoded content in /etc to silence test suites expecting them to be present.

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

internal/rosa/etc.go

@@ -0,0 +1,52 @@
+package rosa
+
+import (
+	"os"
+
+	"hakurei.app/internal/pkg"
+)
+
+// cureEtc contains deterministic elements of /etc, made available as part of
+// [Toolchain]. This silences test suites expecting certain standard files to be
+// available in /etc.
+type cureEtc struct{}
+
+// Cure writes hardcoded configuration to files under etc.
+func (cureEtc) Cure(t *pkg.TContext) (err error) {
+	etc := t.GetWorkDir().Append("etc")
+	if err = os.MkdirAll(etc.String(), 0700); err != nil {
+		return
+	}
+	for _, f := range [][2]string{
+		{"hosts", "127.0.0.1 localhost cure cure-net\n"},
+		{"passwd", `root:x:0:0:System administrator:/proc/nonexistent:/bin/sh
+cure:x:1023:1023:Cure:/usr/src:/bin/sh
+nobody:x:65534:65534:Overflow user:/proc/nonexistent:/system/bin/false
+`},
+		{"group", `root:x:0:
+cure:x:1023:
+nobody:x:65534:
+`},
+	} {
+		if err = os.WriteFile(
+			etc.Append(f[0]).String(),
+			[]byte(f[1]),
+			0400,
+		); err != nil {
+			return
+		}
+	}
+	return os.Chmod(etc.String(), 0500)
+}
+
+// Kind returns the hardcoded [pkg.Kind] value.
+func (cureEtc) Kind() pkg.Kind { return kindEtc }
+
+// Params is a noop.
+func (cureEtc) Params(*pkg.IContext) {}
+
+// Dependencies returns a nil slice.
+func (cureEtc) Dependencies() []pkg.Artifact { return nil }
+
+// String returns a hardcoded reporting name.
+func (cureEtc) String() string { return "cure-etc" }