On 07.07.2016 7:52, K. Macy wrote: > On Wednesday, July 6, 2016, Don Lewis <truck...@freebsd.org> wrote: > >> On 6 Jul, Matthew Macy wrote: >>> As a first step towards managing linux user space in a chrooted >>> /compat/linux, initially for i915 testing with intel gpu tools, later >>> on to get widevine and steam to work I'm trying to get apt to work. >>> I've fixed a number of issues to date in pseudofs/linprocfs but now >>> I'm running in to a bug caused by differences in SIGCHLD handling >>> between Linux and FreeBSD. The situation is that apt will spawn dpkg >>> and wait on a pipe read. On Linux when dpkg exits the SIGCHLD to apt >>> causes a short read on the pipe which lets apt then continue. On >>> FreeBSD a SIGCHLD is silently ignored. I've even experimented with >>> doing a kill -20 <apt pid> to no effect. >>> >>> It would be easy enough to check sysvec against linux in pipe_read and >>> break out of the loop when it's awakened from msleep (assuming there >>> aren't deeper issues with signal propagation for anything other than >>> SIGINT/SIGKILL) and then do a short read. However, I'm assuming that >>> anyone who has worked in this area probably has a cleaner solution. >> >> It shoulds like SA_RESTART is set in sa_flags for SIGCHLD but shouldn't >> be in this case. > > > > Good point. > > Thinking more about it, this seems like a bug in FreeBSD. Not a valid > behavioral difference.
You better need consult with POSIX before fixing things toward any Linuxisms blindly in our native code. I don't have a time now to see, is it really a bug according to POSIX, but please read or just find all SIGCHLD there: http://pubs.opengroup.org/onlinepubs/9699919799/functions/wait.html it explain SIGCHLD actions in deep details. And that one too: http://pubs.opengroup.org/onlinepubs/009695399/functions/sigaction.html _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"