There was a potential chance for a race condition if the ensured section
was purged for some reason before using it later.
This also changes the behavior for NULL/empty strings via load_string*
with merge == FALSE, which now purges the config/section.
Similar to the `also` keyword in ipsec.conf, the new syntax allows adding
one or more references to other sections, which means all the settings and
subsections defined there are inherited (values may be overridden, even
with an empty value to clear it).
It's important to note that all subsections are inherited, so if this is
used to reference a connection in swanctl.conf all auth rounds and
children are inherited. There is currently no syntax to limit the
inclusion level or clear inherited sections (but as mentioned, settings
in those inherited sections may be overridden).
Another property is that inherited settings or sections always follow
explicitly defined entries in the current section when they are enumerated.
This is relevant if the order is important (e.g. for auth rounds if `round`
is not specified).
References are evaluated dynamically at runtime, so referring to
sections later in the config file or included via other files is no
problem.
The colon used as separator to reference other sections may be used in
section names by writing :: (e.g. for Windows log file paths).
This is based on a patch originally written in 2016.
This fixes compilation with -Werror when using Clang 4.0 (but not 3.9)
and possibly prevents undefined behavior.
According to the C standard the following applies to the second
parameter of the va_start() macro (subclause 7.16.1.4, paragraph 4):
The parameter parmN is the identifier of the rightmost parameter
in the variable parameter list in the function definition (the
one just before the ...). If the parameter parmN is declared with
the register storage class, with a function or array type, or with
a type that is not compatible with the type that results after
application of the default argument promotions, the behavior is
undefined.
Because bool is usually just 1 byte and therefore smaller than int (i.e.
the result of default argument promotion) its use as last argument before
... might result in undefined behavior. This theoretically can also
apply to enums as a compiler may use a smaller base type than int.
Since Clang 3.9 (currently in use on Travis by default) a warning is
issued about this, however, that version did not yet compare the actual
size of the argument's type, causing warnings where they are not
warranted (basically for all cases where enum types are used for the
last argument). This was apparently fixed with Clang 4.0, which only
warns about this use of bool with va_start(), which makes sense.
As the behavior was inconsistent for empty strings or strings with characters
appended to a number, testing the code failed on some platforms. The new rules
are more strict, returning the default if additional characters or an empty
string was found for a setting.
This is not thread safe. If threads are reading from pointers to existing
values they could get a partially updated invalid value.
Refactored assignment to a separate function.
Tobias Brunner