Fix UID mismatch bug by directly querying ldapsearch

adduser

@@ -13,8 +13,12 @@ def adduser(username, firstname, lastname, email, password):
     """Add a new user"""
 
     # Get UID
-    output = str(check_output(['getent', 'passwd']))
-    uid = [u for u in range(1000, 10000) if str(u) not in output][0]
+    output = check_output(['ldapsearch', '-x', 'uidNumber']).decode('utf-8')
+    used = set()
+    for line in output.split('\n'):
+        if line.startswith('uidNumber'):
+            used.add(int(line.split()[1]))
+    uid = [u for u in range(1001, 10000) if u not in used][0]
 
     # Construct LDIF
     ldif = f'''dn: uid={username},ou=People,dc=exozy,dc=me
@@ -49,9 +53,9 @@ gidNumber: {uid}'''
     # Add user
     ret = call(['ldapadd', '-D', 'cn=Manager,dc=exozy,dc=me', '-w',
                 open('/etc/ldappass', 'r').read(), '-f', filename])
-    remove(filename)
     if ret != 0:
         return
+    remove(filename)
 
     # Configure and set up user
     # Make home directory