[minicoredumper] D-Bus and inotify removal

John Ogness john.ogness at linutronix.de
Mon Aug 29 15:55:12 CEST 2016


I would like to remove both D-Bus and inotify notification
implementations from minicoredumper. They will be replaced by a single
domain socket implementation. I am asking the minicoredumper community
if there are any objections/concerns about removing the old notification


Until now, libminicoredumper-based applications ran a dedicated thread
that would listen for minicoredumper notifications. Upon receiving such
a notification (either via D-Bus or inotify), each application was
responsible for dumping its own data.


I am working on a new feature where the minicoredumper utility will
extract registered data from other processes, rather than have
applications dumping their data themselves. This has the benefit of not
requiring libminicoredumper-based applications to run an extra
thread. It also means that no broad directory permissions (4777) must
exist within the dump directory. And finally, lower latency can be
achieved because applications must not first be notified to dump.

libminicoredumper-based applications will register/deregister themselves
using UNIX domain sockets with an abstract socket address. This medium
for registration was chosen because it supports automatic credential
conversion so that (for example) the minicoredumper utility will be able
to identify the libminicoredumper-based applications even if they are in
other PID namespaces.


With the upcoming version there have been several important (unrelated)
libminicoredumper API changes. Any application wishing to use the next
libminicoredumper version will be required to re-link the application
anyway. This provides an excellent opportunity for introducing an
alternate notification method since the application must re-link against
the new version.


With the new feature, I would like to remove the D-Bus and inotify-based
implementations. It is conceivable that someone might want to run a
newer version of the minicoredumper utility with an older
libminicoredumper-based application. However, this requires significant
longterm maintenance burdens to make sure the legacy interfaces work
correctly. Also, I believe this will make it more difficult to get the
minicoredumper project accepted by various Linux distributions.

Are there any objections/concerns regarding the removal of D-Bus and
inotify support?

John Ogness

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