varlinkctl: add protocol upgrade support

The varlink spec supports protocol upgrades and they are very useful to e.g. transfer binary data directly via varlink. So far varlinkctl/sd-varlink was not supporting this. This commit adds support for it in varlinkctl by using the new code in sd-varlink and the generalized socket-forward code.
2026-03-31 18:25:09 +02:00
parent 555dde10a0
commit 0fc3f85d35
5 changed files with 217 additions and 4 deletions
@@ -255,3 +255,102 @@ systemd-run --wait --pipe --user --machine testuser@ \
 # test io.systemd.Unit in user manager
 systemd-run --wait --pipe --user --machine testuser@ \
        varlinkctl --more call "/run/user/$testuser_uid/systemd/io.systemd.Manager" io.systemd.Unit.List '{}'
+
+# test --upgrade (protocol upgrade)
+UPGRADE_SOCKET="$(mktemp -d)/upgrade.sock"
+UPGRADE_SERVER="$(mktemp)"
+cat >"$UPGRADE_SERVER" <<'PYEOF'
+#!/usr/bin/env python3
+"""Varlink upgrade test server. With a socket path argument, listens on a unix socket.
+Without arguments, speaks over stdin/stdout (for ssh-exec: transport testing)."""
+import json, os, socket, sys
+
+if len(sys.argv) > 1:
+    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    sock.bind(sys.argv[1])
+    sock.listen(1)
+    print("READY", flush=True)
+    conn, _ = sock.accept()
+    inp = conn.makefile("rb")
+    out = conn.makefile("wb")
+else:
+    inp = sys.stdin.buffer
+    out = sys.stdout.buffer
+    conn = sock = None
+
+# Read the varlink request (NUL-terminated JSON)
+data = b""
+while True:
+    chunk = inp.read(1)
+    assert chunk, "Connection closed before receiving full varlink request"
+    data += chunk
+    if b"\0" in data:
+        break
+
+msg = json.loads(data.split(b"\0")[0])
+received_parameters = msg.get("parameters", {})
+out.write(b'{"parameters": {}}\0')
+out.flush()
+
+# Upgraded protocol: send a non-JSON banner first to prove we're truly in raw mode,
+# then echo the received parameters, then reverse lines from the client
+out.write(b"<<< UPGRADED >>>\n")
+out.write((json.dumps(received_parameters) + "\n").encode())
+out.flush()
+data = inp.read().decode().rstrip("\n")
+out.write((data[::-1] + "\n").encode())
+out.flush()
+
+if conn:
+    conn.close()
+if sock:
+    sock.close()
+PYEOF
+chmod +x "$UPGRADE_SERVER"
+
+# Start the server in the background
+python3 "$UPGRADE_SERVER" "$UPGRADE_SOCKET" &
+SERVER_PID=$!
+
+# Wait for server readiness
+timeout 5 bash -c "while [ ! -S '$UPGRADE_SOCKET' ]; do sleep 0.1; done"
+
+# Test proxy mode: pipe data through --upgrade, passing parameters and validate
+result="$(echo "hello world" | varlinkctl call --upgrade "unix:$UPGRADE_SOCKET" io.systemd.test.Reverse '{"foo":"bar"}')"
+echo "$result" | grep "<<< UPGRADED >>>" >/dev/null
+echo "$result" | grep '"foo": "bar"' >/dev/null
+echo "$result" | grep "dlrow olleh" >/dev/null
+
+wait "$SERVER_PID" || :
+
+# Test --upgrade with stdin redirected from a regular file (epoll can't poll regular files,
+# so this exercises the fork+pipe fallback path)
+UPGRADE_SOCKET2="$(mktemp -d)/upgrade.sock"
+python3 "$UPGRADE_SERVER" "$UPGRADE_SOCKET2" &
+SERVER_PID=$!
+timeout 5 bash -c "while [ ! -S '$UPGRADE_SOCKET2' ]; do sleep 0.1; done"
+
+echo "file input test" > /tmp/test-upgrade-input
+result="$(varlinkctl call --upgrade "unix:$UPGRADE_SOCKET2" io.systemd.test.Reverse '{"foo":"file"}' < /tmp/test-upgrade-input)"
+echo "$result" | grep "<<< UPGRADED >>>" >/dev/null
+echo "$result" | grep '"foo": "file"' >/dev/null
+echo "$result" | grep "tset tupni elif" >/dev/null
+
+wait "$SERVER_PID" || :
+
+# Test --upgrade over ssh-exec: transport (pipe pair, not a bidirectional socket).
+# This exercises the input_fd != output_fd path in sd_varlink_call_and_upgrade().
+# Reuse the same server script without a socket argument - it speaks over stdin/stdout.
+cat > "$SSHBINDIR"/ssh <<EOF
+#!/usr/bin/env bash
+exec python3 "$UPGRADE_SERVER"
+EOF
+chmod +x "$SSHBINDIR"/ssh
+
+result="$(echo "ssh pipe test" | SYSTEMD_SSH="$SSHBINDIR/ssh" varlinkctl call --upgrade ssh-exec:foobar:test-upgrade io.systemd.test.Reverse '{"foo":"ssh"}')"
+echo "$result" | grep "<<< UPGRADED >>>" >/dev/null
+echo "$result" | grep '"foo": "ssh"' >/dev/null
+echo "$result" | grep "tset epip hss" >/dev/null
+
+rm -f "$UPGRADE_SOCKET" "$UPGRADE_SOCKET2" "$UPGRADE_SERVER" /tmp/test-upgrade-input
+rm -rf "$(dirname "$UPGRADE_SOCKET")" "$(dirname "$UPGRADE_SOCKET2")"