[PATCH] dispatch-conf: Add support for update-conf.d hook directory

Those hooks can be used by tools that manage /etc to get notified
about updated configuration files. For example, etckeeper could hook
this mechanism like the following:

/etc/portage/conf-update.d/etckeeper
case "${1}" in
    pre-update)
        etckeeper pre-install
    ;;
    post-update)
		etckeeper post-install
    ;;
esac

Signed-off-by: Florian Schmaus <[email protected]>
Closes: https://bugs.gentoo.org/698316
---
 bin/dispatch-conf            |  8 +++++++-
 lib/portage/dispatch_conf.py | 25 ++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/bin/dispatch-conf b/bin/dispatch-conf
index 1759b89b8..ff9698f14 100755
--- a/bin/dispatch-conf
+++ b/bin/dispatch-conf
@@ -29,7 +29,7 @@ import portage
 portage._internal_caller = True
 from portage import os, shutil
 from portage import _encodings, _unicode_decode
-from portage.dispatch_conf import diffstatusoutput, diff_mixed_wrapper
+from portage.dispatch_conf import diffstatusoutput, diff_mixed_wrapper, perform_conf_update_hooks
 from portage.process import find_binary, spawn
 from portage.util import writemsg, writemsg_stdout
 
@@ -382,11 +382,17 @@ class dispatch:
                 encoding=_encodings["stdio"]) as f:
                 f.write(output + "\n")
 
+        perform_conf_update_hooks("pre-update", curconf)
+
         try:
             os.rename(newconf, curconf)
         except (IOError, os.error) as why:
             writemsg('dispatch-conf: Error renaming %s to %s: %s; fatal\n' % \
                   (newconf, curconf, str(why)), noiselevel=-1)
+            return
+
+        perform_conf_update_hooks("post-update", curconf)
+
 
 
     def post_process(self, curconf):
diff --git a/lib/portage/dispatch_conf.py b/lib/portage/dispatch_conf.py
index 71693bb36..8f40c7724 100644
--- a/lib/portage/dispatch_conf.py
+++ b/lib/portage/dispatch_conf.py
@@ -16,11 +16,13 @@ import subprocess
 import sys
 import tempfile
 
+from collections import OrderedDict
+
 import portage
 from portage import _encodings, os, shutil
 from portage.env.loaders import KeyValuePairFileLoader
 from portage.localization import _
-from portage.util import shlex_split, varexpand
+from portage.util import shlex_split, varexpand, _recursive_file_list
 from portage.util.path import iter_parents
 
 RCS_BRANCH = '1.1.1'
@@ -386,3 +388,24 @@ def file_archive_post_process(archive):
 		if os.path.isdir(dest) and not os.path.islink(dest):
 			_file_archive_rotate(dest)
 		os.rename(archive + '.dist.new', dest)
+
+def perform_conf_update_hooks(kind, conf):
+	conf_update_dir = os.path.join(portage.settings["PORTAGE_CONFIGROOT"],
+		portage.USER_CONFIG_PATH, "conf-update.d")
+	hooks = OrderedDict()
+	for filepath in _recursive_file_list(conf_update_dir):
+		name = filepath.split(conf_update_dir)[1].lstrip(os.sep)
+		if os.access(filepath, os.X_OK):
+			hooks[filepath] = name
+		else:
+			writemsg_level(" %s %s hook: '%s' is not executable\n"
+				       % (warn("*"), _dir, _unicode_decode(name),),
+						level=logging.WARN, noiselevel=2)
+
+	for filepath in hooks:
+		retval = portage.process.spawn([filepath, kind, conf])
+
+		if retval != os.EX_OK:
+			writemsg_level(" %s Spawn failed for: %s, %s\n" % (bad("*"),
+					_unicode_decode(_hooks[filepath]), filepath),
+					level=logging.ERROR, noiselevel=-1)
-- 
2.26.2