SHELL-DAG: NBD proxy — observe-side port/unit read-back on cited extdeps.systemd, retire the systemd-run WitnessBin scaffold

dag/extdeps/systemd/systemctl.dag

@@ -31,6 +31,10 @@ fn systemctl_disable_now_argv(unit: NonEmptyStr) -> List<String> {
   ["systemctl", "disable", "--now", unit as String]
 }
 
+fn systemctl_stop_argv(unit: NonEmptyStr) -> List<String> {
+  ["systemctl", "stop", unit as String]
+}
+
 fn systemctl_set_property_argv(unit: NonEmptyStr, property: NonEmptyStr, value: NonEmptyStr) -> List<String> {
   [
     "systemctl",
@@ -132,6 +136,23 @@ service systemd.Systemctl {
     }
   }
 
+  operation Stop {
+    input { unit: NonEmptyStr }
+    output {
+      success: Bool from "exit_success"
+      stdout: String from "stdout"
+      stderr: String from "stderr"
+    }
+    transport shell { argv: ["systemctl", "stop", "{unit}"] }
+    exit {
+      0 => Unit
+      nonzero => String "systemctl stop failed"
+    }
+    mock_response {
+      0 => { success: true, stdout: "", stderr: "" } "hermetic systemd.Systemctl.Stop"
+    }
+  }
+
   operation SetProperty {
     input { unit: NonEmptyStr, property: NonEmptyStr, value: NonEmptyStr }
     output {
@@ -190,6 +211,9 @@ service systemd.Systemctl {
       3 => Unit "unit is not active"
       nonzero => String "systemctl is-active failed"
     }
+    mock_response {
+      0 => { state: "active", active: true } "hermetic systemd.Systemctl.IsActive active"
+    }
   }
 
   operation ShowProperty {

dag/extdeps/systemd/systemd_run.dag

@@ -0,0 +1,42 @@
+module extdeps.systemd.systemd_run
+
+import std.types { NonEmptyStr, String, List, Bool }
+
+import extdeps.external_authority { ExternalAuthority }
+import extdeps.uri { Uri, Https }
+
+data extdeps_external_authority_anchor: ExternalAuthority = ExternalAuthority {
+  uri: Uri {
+    scheme: Https
+    locator: "www.freedesktop.org/software/systemd/man/latest/systemd-run.html"
+  }
+}
+
+data systemd_run_authority: ExternalAuthority = extdeps_external_authority_anchor
+
+fn systemd_run_transient_unit_argv(unit: NonEmptyStr, command_argv: List<String>) -> List<String> {
+  fold(
+    command_argv,
+    init: ["systemd-run", concat("--unit=", unit as String), "--collect", "--"],
+    f: (acc, arg) => list_push(acc, arg),
+  )
+}
+
+service systemd.SystemdRun {
+  operation RunTransient {
+    input { unit: NonEmptyStr, command_argv: List<String> }
+    output {
+      success: Bool from "exit_success"
+      stdout: String from "stdout"
+      stderr: String from "stderr"
+    }
+    transport shell { argv: ["systemd-run", "--unit={unit}", "--collect", "--", command_argv] }
+    exit {
+      0 => Unit
+      nonzero => String "systemd-run transient unit start failed"
+    }
+    mock_response {
+      0 => { success: true, stdout: "Running as unit: demo.service", stderr: "" } "hermetic systemd.SystemdRun.RunTransient"
+    }
+  }
+}