1 files changed, 134 insertions, 0 deletions
diff --git a/test/features/steps/behave_agent.py b/test/features/steps/behave_agent.py
new file mode 100755
index 0000000..eafeedd
--- /dev/null
+++ b/test/features/steps/behave_agent.py
@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+# behave_agent.py - a simple agent to execute command
+# NO AUTHENTICATIONS. It should only be used in behave test.
+import io
+import os
+import pwd
+import socket
+import struct
+import subprocess
+import typing
+
+
+MSG_EOF  = 0
+MSG_USER = 1
+MSG_CMD  = 2
+MSG_OUT  = 4 
+MSG_ERR  = 5
+MSG_RC   = 6
+
+
+class Message:
+    @staticmethod
+    def write(output, type: int, data: bytes):
+        output.write(struct.pack('!ii', type, len(data)))
+        output.write(data)
+
+    @staticmethod
+    def read(input):
+        buf = input.read(8)
+        type, length = struct.unpack('!ii', buf)
+        if length > 0:
+            buf = input.read(length)
+        else:
+            buf = b''
+        return type, buf
+
+
+class SocketIO(io.RawIOBase):
+    def __init__(self, s: socket.socket):
+        self._socket = s
+
+    def readable(self) -> bool:
+        return True
+
+    def writable(self) -> bool:
+        return True
+
+    def read(self, __size: int = -1) -> bytes:
+        return self._socket.recv(__size)
+
+    def readinto(self, __buffer) -> int:
+        return self._socket.recv_into(__buffer)
+
+    def readall(self) -> bytes:
+        raise NotImplementedError
+
+    def write(self, __b) -> int:
+        return self._socket.send(__b)
+
+
+def call(host: str, port: int, cmdline: str, user: typing.Optional[str] = None):
+    family, type, proto, _, sockaddr =  socket.getaddrinfo(host, port, type=socket.SOCK_STREAM)[0]
+    with socket.socket(family, type, proto) as s:
+        s.connect(sockaddr)
+        sout = io.BufferedWriter(SocketIO(s), 4096)
+        Message.write(sout, MSG_USER, user.encode('utf-8') if user else _getuser().encode('utf-8'))
+        Message.write(sout, MSG_CMD, cmdline.encode('utf-8'))
+        Message.write(sout, MSG_EOF, b'')
+        sout.flush()
+        s.shutdown(socket.SHUT_WR)
+        rc = None
+        stdout = []
+        stderr = []
+        sin = io.BufferedReader(SocketIO(s), 4096)
+        while True:
+            type, buf = Message.read(sin)
+            if type == MSG_OUT:
+                stdout.append(buf)
+            elif type == MSG_ERR:
+                stderr.append(buf)
+            elif type == MSG_RC:
+                rc, = struct.unpack('!i', buf)
+            elif type == MSG_EOF:
+                assert rc is not None
+                return rc, b''.join(stdout), b''.join(stderr)
+            else:
+                raise ValueError(f"Unknown message type: {type}")
+
+
+def serve(stdin, stdout, stderr):
+    # This is an xinetd-style service.
+    assert os.geteuid() == 0
+    user = None
+    cmd = None
+    sin = io.BufferedReader(stdin)
+    while True:
+        type, buf = Message.read(sin)
+        if type == MSG_USER:
+            user = buf.decode('utf-8')
+        elif type == MSG_CMD:
+            cmd = buf.decode('utf-8')
+        elif type == MSG_EOF:
+            assert user is not None
+            assert cmd is not None
+            break
+        else:
+            raise ValueError(f"Unknown message type: {type}")
+    if user == 'root':
+        args = ['/bin/sh']
+    else:
+        args = ['/bin/su', '-', user, '-c', '/bin/sh']
+    result = subprocess.run(
+        args,
+        input=cmd.encode('utf-8'),
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    )
+    sout = io.BufferedWriter(stdout)
+    Message.write(sout, MSG_RC, struct.pack('!i', result.returncode))
+    Message.write(sout, MSG_OUT, result.stdout)
+    Message.write(sout, MSG_ERR, result.stderr)
+    Message.write(sout, MSG_EOF, b'')
+    stdout.flush()
+
+
+def _getuser():
+    return pwd.getpwuid(os.geteuid()).pw_name
+
+
+if __name__ == '__main__':
+    with open(0, 'rb') as stdin, \
+         open(1, 'wb') as stdout, \
+         open(2, 'wb') as stderr:
+        serve(stdin, stdout, stderr)