modem: add van-sms-send CLI for sending SMS ad hoc

mmcli's inline "number=...,text=..." properties string breaks on plain
spaces/quotes/colons in the text — found while testing van-sms-watch.
Sidesteps that entirely by passing the message via
--messaging-create-sms-with-text=<tempfile> instead. Tested live
(multi-word text, punctuation, multi-line stdin input all delivered).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

deploy.sh

@@ -156,6 +156,9 @@ install_rendered failover/van-modem-watch.service /etc/systemd/system/van-modem-
 # can't be fetched here (see script docstring) — notification-only paging.
 install -D -m0755 modem/van-sms-watch         /usr/local/sbin/van-sms-watch
 install -D -m0644 modem/van-sms-watch.service /etc/systemd/system/van-sms-watch.service
+# CLI to send an SMS ad hoc (needs sudo — ModemManager's Messaging actions
+# are PolicyKit-gated). Not a service, just a tool: sudo van-sms-send <number> <text>
+install -D -m0755 modem/van-sms-send /usr/local/sbin/van-sms-send
 
 echo "== cockpit plugin =="
 install -d /usr/share/cockpit/vanrouter

modem/van-sms-send

@@ -0,0 +1,96 @@
+#!/usr/bin/env python3
+"""van-sms-send — send an SMS through the EC25 modem from the command line.
+
+Usage:
+  van-sms-send <number> <text...>
+  echo "message text" | van-sms-send <number>
+
+The message is written to a temp file and passed via mmcli's
+--messaging-create-sms-with-text (rather than inline in the "number=...,
+text=..." properties string) — mmcli's properties-string parser breaks on
+plain spaces/quotes/colons in inline text (found the hard way testing
+van-sms-watch), the file form has none of that trouble.
+
+Needs root: ModemManager's Messaging/Device.Control D-Bus actions are
+PolicyKit-gated and unauthorized for a plain user session (read-only
+actions like listing SMS work unprivileged; creating/sending don't). Run
+with sudo.
+
+Stdlib only.
+"""
+
+import json
+import subprocess
+import sys
+import tempfile
+
+
+def die(msg):
+    print(f"van-sms-send: {msg}", file=sys.stderr)
+    sys.exit(1)
+
+
+def run_json(args):
+    """Run mmcli with -J and return the parsed dict, dying on any failure."""
+    try:
+        out = subprocess.run(["mmcli", "-J", *args], capture_output=True,
+                             text=True, timeout=20)
+    except Exception as e:
+        die(f"failed to run mmcli {' '.join(args)}: {e}")
+    if out.returncode != 0:
+        die(f"mmcli {' '.join(args)} failed: {out.stderr.strip() or out.stdout.strip()}")
+    try:
+        return json.loads(out.stdout)
+    except Exception as e:
+        die(f"mmcli {' '.join(args)} gave unparseable JSON ({e}): {out.stdout}")
+
+
+def run_action(args):
+    """Run mmcli for an action whose success is exit-code only (no JSON body
+    even with -J, e.g. --send). Dies on failure."""
+    try:
+        out = subprocess.run(["mmcli", *args], capture_output=True, text=True, timeout=20)
+    except Exception as e:
+        die(f"failed to run mmcli {' '.join(args)}: {e}")
+    if out.returncode != 0:
+        die(f"mmcli {' '.join(args)} failed: {out.stderr.strip() or out.stdout.strip()}")
+
+
+def find_modem():
+    modems = run_json(["-L"]).get("modem-list") or []
+    return modems[0] if modems else None
+
+
+def main():
+    if len(sys.argv) < 2:
+        die("usage: van-sms-send <number> <text...>  (or pipe text on stdin)")
+    number = sys.argv[1]
+    if len(sys.argv) > 2:
+        text = " ".join(sys.argv[2:])
+    elif not sys.stdin.isatty():
+        text = sys.stdin.read().rstrip("\n")
+    else:
+        die("no message text given as an argument or on stdin")
+    if not text:
+        die("message text is empty")
+
+    modem = find_modem()
+    if not modem:
+        die("no modem found (mmcli -L found none)")
+
+    with tempfile.NamedTemporaryFile("w", suffix=".txt") as f:
+        f.write(text)
+        f.flush()
+        created = run_json(["-m", modem, f"--messaging-create-sms=number={number}",
+                            f"--messaging-create-sms-with-text={f.name}"])
+
+    sms_path = (created.get("modem") or {}).get("messaging", {}).get("created-sms")
+    if not sms_path:
+        die(f"couldn't find created SMS path in mmcli output: {created}")
+
+    run_action(["-m", modem, "-s", sms_path, "--send"])
+    print(f"sent to {number}: {text}")
+
+
+if __name__ == "__main__":
+    main()