The behaviour of the common name##_from_string conversion is surprising.
It accepts not only the strings from name##_table but also any number
that falls within the range of the table. The order of items in most of
our tables is an internal affair. It should not be visible to the user.
I know of a case where the surprising numeric conversion leads to a crash.
We will allow the direct numeric conversion only for the tables where the
mapping of strings to numeric values has an external meaning. This holds
for the following lookup tables:
- netlink_family, ioprio_class, ip_tos, sched_policy - their numeric
values are stable as they are defined by the Linux kernel interface.
- log_level, log_facility_unshifted - the well-known syslog interface.
We allow the user to use numeric values whose string names systemd does
not know. For instance, the user may want to test a new kernel featuring
a scheduling policy that did not exist when his systemd version was
released. A slightly unpleasant effect of this is that the
name##_to_string conversion cannot return pointers to constant strings
anymore. The strings have to be allocated on demand and freed by the
caller.
We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.
Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.
The bits that used to be MIT continue to be MIT.
The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
Zbigniew Jędrzejewski-Szmek