server: serve should be a context manager

sshagent/server.py

@@ -68,21 +68,8 @@ def spawn(func, **kwargs):
     t.join()
 
 
-def run(command, environ):
-    log.debug('running %r with %r', command, environ)
-    env = dict(os.environ)
-    env.update(environ)
-    try:
-        p = subprocess.Popen(args=command, env=env)
-    except OSError as e:
-        raise OSError('cannot run %r: %s' % (command, e))
-    log.debug('subprocess %d is running', p.pid)
-    ret = p.wait()
-    log.debug('subprocess %d exited: %d', p.pid, ret)
-    return ret
-
-
-def serve(key_files, command, signer, sock_path=None):
+@contextlib.contextmanager
+def serve(key_files, signer, sock_path=None):
     if sock_path is None:
         sock_path = tempfile.mktemp(prefix='ssh-agent-')
 
@@ -91,8 +78,21 @@ def serve(key_files, command, signer, sock_path=None):
     with unix_domain_socket_server(sock_path) as server:
         with spawn(server_thread, server=server, keys=keys, signer=signer):
             try:
-                ret = run(command=command, environ=environ)
+                yield environ
             finally:
                 log.debug('closing server')
                 server.shutdown(socket.SHUT_RD)
+
+
+def run_process(command, environ):
+    log.debug('running %r with %r', command, environ)
+    env = dict(os.environ)
+    env.update(environ)
+    try:
+        p = subprocess.Popen(args=command, env=env)
+    except OSError as e:
+        raise OSError('cannot run %r: %s' % (command, e))
+    log.debug('subprocess %d is running', p.pid)
+    ret = p.wait()
+    log.debug('subprocess %d exited: %d', p.pid, ret)
     return ret

sshagent/trezor_agent.py

@@ -22,30 +22,24 @@ def main():
     level = verbosity[min(args.verbose, len(verbosity) - 1)]
     logging.basicConfig(level=level, format=fmt)
 
-    client = trezor.Client(factory=trezor.TrezorLibrary)
-
-    key_files = []
-    for label in args.labels:
-        pubkey = client.get_public_key(label=label)
-        key_file = formats.export_public_key(pubkey=pubkey, label=label)
-        key_files.append(key_file)
-
-    if not args.command:
-        sys.stdout.write(''.join(key_files))
-        return
-
-    signer = client.sign_ssh_challenge
-
-    ret = -1
-    try:
-        ret = server.serve(
-            key_files=key_files,
-            command=args.command,
-            signer=signer)
-        log.info('exitcode: %d', ret)
-    except KeyboardInterrupt:
-        log.info('server stopped')
-    sys.exit(ret)
+    with trezor.Client(factory=trezor.TrezorLibrary) as client:
+        key_files = []
+        for label in args.labels:
+            pubkey = client.get_public_key(label=label)
+            key_file = formats.export_public_key(pubkey=pubkey, label=label)
+            key_files.append(key_file)
+
+        if not args.command:
+            sys.stdout.write(''.join(key_files))
+            return
+
+        signer = client.sign_ssh_challenge
+
+        try:
+            with server.serve(key_files=key_files, signer=signer) as env:
+                return server.run_process(command=args.command, environ=env)
+        except KeyboardInterrupt:
+            log.info('server stopped')
 
 if __name__ == '__main__':
-    main()
+    sys.exit(main())