From df421db0719fda8cdfb6687f36114ea36892c181 Mon Sep 17 00:00:00 2001
From: Emery Hemingway <ehmry@posteo.net>
Date: Thu, 18 May 2023 18:08:59 +0100
Subject: [PATCH] msg: make the SturdyRef overrideable with $SYNDICATE_STEP

---
 README.md   | 3 ++-
 src/msg.nim | 7 ++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index a7c8d65..80d73a6 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,8 @@ Do not send messages immediately to the dataspace passed `json_socket_translator
 
 ## msg
 
-A utility that sends a message to $SYNDICATE_SOCK in the form `<ARGV…>`.
+A utility that sends a message to `$SYNDICATE_SOCK` in the form `<ARGV0 ARG1 … ARGVn>`.
+The `$SYNDICATE_STEP` variables sets the SturdyRef capability with a default to the SturdyRef generated by `<ref { oid: "syndicate" key: #x"" }>`.
 
 ## preserve_process_environment
 
diff --git a/src/msg.nim b/src/msg.nim
index b7bd7c4..b2d9a32 100644
--- a/src/msg.nim
+++ b/src/msg.nim
@@ -9,10 +9,15 @@ proc unixSocketPath: Unix =
   if result.path == "":
     result.path = getEnv("XDG_RUNTIME_DIR", "/run/user/1000") / "dataspace"
 
+proc envStep: Preserve[Ref] =
+  var s = getEnv("SYNDICATE_STEP")
+  if s != "": parsePreserves(s, Ref)
+  else: capabilities.mint().toPreserve(Ref)
+
 proc main =
   let label = getAppFilename().extractFilename
   bootDataspace(label) do (root: Ref; turn: var Turn):
-    connect(turn, unixSocketPath(), capabilities.mint().toPreserve(Ref)) do (turn: var Turn; ds: Ref):
+    connect(turn, unixSocketPath(), envStep()) do (turn: var Turn; ds: Ref):
       message(turn, ds, initRecord(label, map(commandLineParams(), parsePreserves)))
 
   for i in 0..3: poll(20)