With the exponential backoff, we can perform more requests in the same amount of time,
so bump this a bit.
In case of large RTT this may be necessary in order not to regress, and in case
of large packet-loss it will make us more robust. The latter is particularly
relevant once we start probing for features (and hence may see packet-loss
until we settle on the right feature level).
Rather than fixing this to 5s for unicast DNS and 1s for LLMNR, start
at a tenth of those values and increase exponentially until the old
values are reached. For LLMNR the recommended timeout for IEEE802
networks (which basically means all of the ones we care about) is 100ms,
so that should be uncontroversial. For unicast DNS I have found no
recommended value. However, it seems vastly more likely that hitting a
500ms timeout is casued by a packet loss, rather than the RTT genuinely
being greater than 500ms, so taking this as a startnig value seems
reasonable to me.
In the common case this greatly reduces the latency due to normal packet
loss. Moreover, once we get support for probing for features, this means
that we can send more packets before degrading the feature level whilst
still allowing us to settle on the correct feature level in a reasonable
timeframe.
The timeouts are tracked per server (or per scope for the multicast
protocols), and once a server (or scope) receives a successfull package
the timeout is reset. We also track the largest RTT for the given
server/scope, and always start our timouts at twice the largest
observed RTT.
Using --size option triggers an assert failure below because
parse_size() requires the second argument, base, being either 1000 or
1024. As it's for a packet size, it'd be better using IEC binary
suffix (base 1024) IMHO.
$ busctl --size 2048
Assertion 'base == 1000 || base == 1024' failed at src/basic/util.c:2222,
function parse_size(). Aborting.
Aborted (core dumped)
In member_compare_func(), it compares interface, type and name of
members. But as it can contain NULL pointer, it needs to check them
before calling strcmp(). So make it as a separate strcmp_ptr
function (named after streq_ptr) so that it can be used by others.
Also let streq_ptr() to use it in order to make the code simpler.
Given two bitmaps and the following code:
Bitmap *a = bitmap_new(), *b = bitmap_new();
bitmap_set(a, 1);
bitmap_clear(a);
bitmap_set(a, 0);
bitmap_set(b, 0);
These two bitmaps should now have the same bits set and they should be
equal but bitmap_equal() will return false in this case because while
bitmap_clear() resets the number of elements in the array it does not
clear the array and bitmap_set() expects the array to be cleared.
GREEDY_REALLOC0 looks at the allocated size and not the actual size so
it does not clear any memory.
Fix this by freeing the allocated memory and resetting the whole Bitmap
to an initial state in bitmap_clear().
This also adds test code for this issue.
Given two bitmaps and the following code:
Bitmap *a = bitmap_new(), *b = bitmap_new();
bitmap_set(a, 0);
bitmap_unset(a, 0);
These two bitmaps should now have the same bits set and they should be
equal but bitmap_equal() will return false in this case because the
bitmaps array in a is larger because of the bit which was previously
set.
Fix this by comparing only the bits which exists in both bitmaps and
then check that the rest of the bits (if any) is all zero.
This also adds test code for this issue.
Make sure we release VT-positions when a session is closed. Otherwise,
lingering sessions will occupy VTs and prevent next logins from
succeeding.
Note that we already release session-devices when closing a session, so
there cannot be anyone using the VT anymore.
If we generate messages from within bus-proxyd, we really must make sure
that we do not clutter the cookie-namespace of our client. The client has
full control over it, so we cannot steal cookies from it. However, we can
re-use the cookie the client used for our request. As long as we only
send a single message, we're fine.
The StartServiceByName() call was provided by dbus-daemon to activate a
service without sending a message. On receiption, dbus-daemon schedules
an activation request (different modes are supported) and sends back the
reply once activation is done.
With kdbus, we marked StartServiceByName() as deprecated. There is no
real reason to start services explicitly. Instead, applications should
just *use* the service and rely on it being activated implicitly.
However, we provide compatibility with dbus-daemon and implement
StartServiceByName() on the proxy via a call to
org.freedesktop.DBus.Peer.Ping() on the destination. This will activate
the peer implicitly as part of the no-op Ping() method call (regardless
whether the peer actually implements that call).
Now, the problem is, StartServiceByName() was synchronous on dbus-daemon
but isn't on bus-proxy. Hence, on return, there is no guarantee that
ListNames includes the activated name. As this is required by some
applications, we need to make this synchronous.
This patch makes the proxy track the Ping() method call and send the
reply of StartServiceByName() only once Ping() returned. We do not look
at possible errors of Ping(), as there is no strict requirement for the
peer to implement org.freedesktop.DBus.Peer. Furthermore, any interesting
error should have already been caught by sd_bus_send() before.
Note:
This race was triggered by gdbus. The gdbus-proxy implementation
relies on a name to be available after StartServiceByName()
returns. This is highly fragile and should be dropped by gdbus.
Even if the call is synchronous, there is no reason whatsoever to
assume the service did not exit-on-idle before ListNames()
returns.
However, this race is much less likely than the startup race, so
we try to be compatible to dbus-daemon now.
AC_CHECK_FILE fails when cross-compiling. It is intended to be used to
check for files that are used at runtime during build time (e.g.
/etc/passwd, /dev/*) [1]. For files which are only used at build time
'test -f' is sufficient.
[1]: https://lists.gnu.org/archive/html/autoconf/2000-10/msg00018.html
NameAcquired and NameLost are directed signals. Never ever filter them on
dbus1. On dbus1, filters *exclusively* apply to broadcasts! Hence, we
must always forward directed signals unconditionally!
Probably a typo, checking 'ret' instead of the return value 'p'. This
might cause the function to return failure, even though it succeeded.
Furthermore, it might leak resources.
