commands: update smb.conf post- provision and join funcs

Global options passed to the samba-tool commands do no persist in the
smb.conf generated by samba-tool domain {provision,join} commands.  In
order to get custom global configurations into the AD DC we can instead
use the smbconf configuration reader to read the current smb.conf and
merge in any options defined in the sambacc configuration.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

sambacc/commands/addc.py

@@ -19,9 +19,12 @@
 import logging
 import os
 import shutil
+import typing
 
 from sambacc import addc
 from sambacc import samba_cmds
+from sambacc import smbconf_api
+from sambacc import smbconf_samba
 
 from .cli import best_waiter, CommandBuilder, Context, Fail
 
@@ -88,6 +91,7 @@ def _prep_provision(ctx: Context) -> None:
         admin_password=domconfig.admin_password,
         options=ctx.instance_config.global_options(),
     )
+    _merge_config(_provisioned, ctx.instance_config.global_options())
 
 
 def _prep_join(ctx: Context) -> None:
@@ -105,6 +109,27 @@ def _prep_join(ctx: Context) -> None:
         admin_password=domconfig.admin_password,
         options=ctx.instance_config.global_options(),
     )
+    _merge_config(_provisioned, ctx.instance_config.global_options())
+
+
+def _merge_config(
+    smb_conf_path: str,
+    options: typing.Optional[typing.Iterable[tuple[str, str]]] = None,
+) -> None:
+    if not options:
+        return
+    txt_conf = smbconf_samba.SMBConf.from_file(smb_conf_path)
+    tmp_conf = smbconf_api.SimpleConfigStore()
+    tmp_conf.import_smbconf(txt_conf)
+    global_section = dict(tmp_conf["global"])
+    global_section.update(options)
+    tmp_conf["global"] = list(global_section.items())
+    try:
+        os.rename(smb_conf_path, f"{smb_conf_path}.orig")
+    except OSError:
+        pass
+    with open(smb_conf_path, "w") as fh:
+        smbconf_api.write_store_as_smb_conf(fh, tmp_conf)
 
 
 def _prep_wait_on_domain(ctx: Context) -> None: