On Mon, 2012-10-29 at 20:00 +0100, Enrico Scholz wrote: > Richard Purdie <[email protected]> writes: > > >> >> But the real bug is the time mismatch in the autobuilders, isn't it? > >> >> And this can/should be solved by synchronizing time by ntp on them > >> >> instead of applying dirty hacks like resetting file dates. > >> ... > >> > Worse, when this does happen the failures are extremely unpredictable > >> > and hard to debug. It causes things to repeatedly recompile for example, > >> > even during do_install. > > ... > > Set the date stamp of some headers in the target sysroot of some key > > system components (say glib) to a date about a day in the future, > > Are there really packages which create files dated in the future? > Perhaps a sanity check should be written which rejects files which are > newer than their containing directory and/or the time-of-day? > > > then clean and rebuild some software that uses glib. > > How will 'tar -m' fix this? It makes things just worse because the > files generated with -m are always newer than without -m (in practice, > time offset between hosts served by ntp is far below 100ms. which is > enough for the build stages doing the sstage file extraction).
Imagine system A generates the sysroot headers with a time ahead of system B. These are packaged up into an sstate tarball. System B which has a clock at some time behind system A then downloads and uses them so the sysroot headers become some time in the future. You then see the problem I described previously. tar -m fixes this by timestamping things at the time of extraction, thereby removing any issue of the timestamps being in the future. Yes, we could add a step which iterated over the extracted files and checked to see if any were in the future and if so, change their timestamps but it seems a bit overkill when the option to tar resolves all the problems. The alternative is to mandate *every* system that builds are run on use ntp and add checks to sanity.bbclass to this effect since someone might try using a sstate feed with a bad clock. This would cause no end of problems, not least with corporate filewalls and hurt usability of the project so we took the other option which fixes things in a way this should become a non-issue. Cheers, Richard _______________________________________________ Openembedded-core mailing list [email protected] http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core
