conf-parser: let's explicitly deprecate .include in unit files

.include lines are already deprecated somewhat, and for example
explicitly not mentioned in the documentation for this reason. Let's get
one step further and generatea warning when we encounter them (but still
process them).

Why are they deprecated? Because they are semantically awful — they
complicate stat() based mtime checks for configuration files and they
allow arbitrary loops we currently have zero protection against and
really shouldn't have to have.

diff --git a/src/shared/conf-parser.c b/src/shared/conf-parser.c
index 72c47150d0ca0ca77456eb84d03ca9d93b271651..0ac636457741d4d624636e26259b634482ed3419 100644 (file)
--- a/src/shared/conf-parser.c
+++ b/src/shared/conf-parser.c
@@ -211,6 +211,10 @@ static int parse_line(
                         return 0;
                 }
 
+                log_syntax(unit, LOG_WARNING, filename, line, 0,
+                           ".include directives are deprecated, and support for them will be removed in a future version of systemd. "
+                           "Please use drop-in files instead.");
+
                 fn = file_in_same_dir(filename, strstrip(l+9));
                 if (!fn)
                         return -ENOMEM;