Now that we can selectively suppress only sensitive fields in JSON
objects we can reenable debug logging for incoming messages, which was
removed in 2e3414660c.
This makes Varlink fully debuggable again: we'll see both incoming and
outgoing messages, only the sensitive fields are suppressed.
See: #30578
Previously, the flag would completely refuse formatting a JSON object if
any field of it was marked sensitive. With this change we'll simply
replace the subobject with the string "<sensitive data>", and show
everything else.
This is tremendously useful when debugging, since it means that we can
again trace varlink calls through the stack: we can show all the message
metadata and just suppress the actually sensitive parameters.
The ability to debug this matters, and we should not hide more
information that we can get away with, to keep things debuggable and
maintainable.
Let's export this function, so that we can use it elsewhere. Also, while
at it, let's cache the result in a flag. This is only safe if the result
is positive, since we allow the flag to be enabled at any time down thre
tree somewhere, which we need to look at. (We never allow it to be
turned off however)
So far the varlink logic honoured the "sensitive" flag of output
messages. Let's add something similar for input messages. Since we don't
really know incoming messages, the flag simply controls whether the
"parmaeters" field of all incoming messages should be marked as
sensitive.
Then, turn this on in the credentials logic and in homed, since both
deal with credentials.
The kernel uses different logics to find or distinguish IPv4 and IPv6 routes.
Let's follow the same way that the kernel uses.
See comments in the code for more details.
To prevent the request freed in req->process().
This also makes a request that is not requested by a link detached on failure.
Otherwise, the request may periodically processed and failed forever.
Let's rename return parameters to ret_xyz, and let's guarantee the usual
rule to initialize all return parameters on success, and not touch any
on failure.
Don't recalculate the overall offset entirely each time we process
another header. Instead, if we already validated an earlier offset, just
reuse the result, it's readily available in 'p'.
No change in behaviour, just a bit of code simplification.
A positive return value means "access granted", hence if we already
reply to the method call don't accidentally return positive.
Follow-up for: d04c1a1c8e
varlink_server_listen_auto() is supposed to be the one-stop solution for
turning simple command line tools into IPC services. They aren't easy to
test/debug however, since you have to invoke them through a service
manager.
Let's make this easier: if the SYSTEMD_VARLINK_LISTEN env var is set,
let's listen on the socket specified therein. This makes things easier
to gdb: just run the service from the cmdline.
Let's improve debuggability of varlink IPC transactions, and separate
out log messages triggered by the IPC info from others, by prefixing
them with a specific prefix.
If a nexthop is removed, dependent nexthops are silently removed by the
kernel. Hence, networkd may be confused that nexthops that depends on the
nexthop still exist, and may fail to configure other routes or so.
Also, this renames 'req' -> 'm', and makes the function unconditionally
set route type and route metric, and override type later if necessary.
Should not change any effective behavior. Just refactoring.
