+##
+# Check the local user keys.
+#
+# This function checks if the keyids defined through the --local-user
+# command line option or set in .caffrc are valid and known to be one of the
+# keyids listed in ./caffrc. The last check ensure we have those keyids
+# available in the caff's gnupghome directory.
+#
+# @return an array containing the local user keys\n
+# (undef) if no key has been specified
+#
+sub get_local_user_keys()
+{
+ my @local_user = ();
+ my @key_list;
+
+ # No user-defined key id has been specified by the user, no need for
+ # further checks
+ if (!$CONFIG{'local-user'}) {
+ return (undef);
+ }
+
+ # Parse the list of keys
+ if (ref($CONFIG{'local-user'})) {
+ @key_list = @{$CONFIG{'local-user'}};
+ }
+ else {
+ @key_list = split /\s*,\s*/, $CONFIG{'local-user'};
+ }
+
+ # Check every key defined by the user...
+ for my $user_key (@key_list) {
+
+ $user_key =~ s/^0x//i;
+ $user_key = uc($user_key);
+
+ unless ($user_key =~ m/^([A-F0-9]{8}|[A-F0-9]{16}|[A-F0-9]{40})$/) {
+ mywarn "Local-user $user_key is not a valid keyid.";
+ next;
+ }
+
+ unless (grep (/$user_key$/, @{$CONFIG{'keyid'}})) {
+ mywarn "Local-user $user_key is not defined as one of your keyid in ./caffrc (it will not be used).";
+ next;
+ }
+
+ push (@local_user, $user_key);
+ }
+
+ # If no local-user key are valid, there is no need to go further
+ unless (defined $local_user[0]) {
+ myerror (1, "None of the local-user keys seem to be known as a keyid listed in ./caffrc.");
+ }
+
+ return @local_user;
+}
+