1 files changed, 65 insertions, 0 deletions
diff --git a/cloud_mdir_sync/credsrv.py b/cloud_mdir_sync/credsrv.py
new file mode 100644
index 0000000..97357bc
--- /dev/null
+++ b/cloud_mdir_sync/credsrv.py
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: GPL-2.0+
+import asyncio
+import contextlib
+import os
+import re
+from typing import List
+
+from . import config, oauth
+
+
+class CredentialServer(object):
+    """Serve XOAUTH2 bearer tokens over a unix domain socket. The client
+    writes the user to obtain a token for and the server responds with the
+    token"""
+    def __init__(self,
+                 cfg: config.Config,
+                 path: str,
+                 accounts: List[oauth.Account],
+                 umask=0o600):
+        self.cfg = cfg
+        self.path = os.path.abspath(os.path.expanduser(path))
+        self.umask = umask
+        self.accounts = {}
+        for I in accounts:
+            I.oauth_smtp = True
+            self.accounts[I.user] = I
+
+    async def go(self):
+        old_umask = os.umask(self.umask)
+        try:
+            self.server = await asyncio.start_unix_server(
+                self.handle_client, self.path)
+        finally:
+            os.umask(old_umask)
+        os.chmod(self.path, self.umask)
+
+    async def close(self):
+        pass
+
+    async def handle_client(self, reader: asyncio.StreamReader,
+                            writer: asyncio.StreamWriter) -> None:
+        with contextlib.closing(writer):
+            req = await reader.read()
+            g = re.match(r"([^ ,]+)(?:,(\S+))? (\S+@\S+)", req.decode())
+            if g is None:
+                self.cfg.logger.error(f"Invalid credential request {req!r}")
+                return
+            proto, opts_str, user = g.groups()
+            if opts_str:
+                opts = opts_str.split(',')
+            else:
+                opts = []
+
+            self.cfg.logger.debug(
+                f"Credential request {proto!r} {opts} {user!r}")
+
+            account = self.accounts.get(user)
+            if account is None:
+                return
+
+            xoauth2 = await account.get_xoauth2_bytes("SMTP")
+            if xoauth2 is None:
+                return
+            writer.write(xoauth2)
+            await writer.drain()