Hello, Thank you everyone for the assistance and quick response. Thankfully adding the Environment with LD_PRELOAD in the systemd service file was enough to get everything running smoothly.
Regards, Mosleh On Wed, Feb 20, 2019 at 3:06 PM Jonathan Rajotte-Julien < jonathan.rajotte-jul...@efficios.com> wrote: > > One should be able to add LD_PRELOAD to an Environment line in a > > systemd unit file. But beware, from ld.so docs: > > > > In secure-execution mode, preload pathnames containing slashes are > > ignored. Furthermore, shared objects are preloaded only from the > > standard search directories and only if they have set-user-ID mode bit > > enabled (which is not typical). > > Those are all valid constraints and if I'm not mistaken can be controlled > by a > system administrator. Thanks for bringing it up. > > > > > Another way that setting ld_preload can be hard is when the program > > that needs it is started by another process that does not need it. > > Like say "mount" will fork and exec "losetup". How do you set > > LD_PRELOAD for just losetup without getting mount too? Modify the code > > of mount to inject an environment variable? > > Unfortunately, for now, yes, if you know that the application that you > exec is > instrumented with lttng and will perform either a fork call not followed > by an > exec (family) call and/or close all FDs. > > > Make a wrapper script > > named losetup that sets LD_PRELOAD and runs the real losetup binary? > > This is valid option. > > We do have a potential solution to eliminate the need of preloading the > fork > wrapper but we did not yet have time to work on it. > > As for the FD lib utility (liblttng-ust-fd) we are open to opinion on how > to > solve the problem and make liblttng-ust-fd obsolete. > > Cheers > -- > Jonathan Rajotte-Julien > EfficiOS >
_______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
