Date: Mon, 9 Mar 2009 01:23:23 -0400 (EDT) From: Daniel Eischen <deischen@freebsd.org> To: David Xu <davidxu@freebsd.org> Cc: threads@freebsd.org, Pawel Worach <pawel.worach@gmail.com> Subject: Re: libthr does not obey WITHOUT_SYSCALL_COMPAT Message-ID: <Pine.GSO.4.64.0903090114380.8422@sea.ntplx.net> In-Reply-To: <49B4A571.7000302@freebsd.org> References: <d227e09e0903041123i638a12b8m5d8573cc871d1533@mail.gmail.com> <49B480F7.8040800@freebsd.org> <Pine.GSO.4.64.0903082343280.8064@sea.ntplx.net> <49B4A571.7000302@freebsd.org>
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On Mon, 9 Mar 2009, David Xu wrote: > Daniel Eischen wrote: >> On Mon, 9 Mar 2009, David Xu wrote: >> >>> Pawel Worach wrote: >>>> Hi, >>>> >>>> If libc is built using WITHOUT_SYSCALL_COMPAT applications linked with >>>> libthr end up having unresolved symbols since libthr references >>>> __fcntl_compat unconditionally. >>>> Here is a patch to make libthr also obey WITHOUT_SYSCALL_COMPAT >>>> http://www.vlakno.cz/~pwo/libthr.diff >>>> >>>> Regards >>> >>> Committed! >> >> I never got around to replying to this... >> >> I don't quite understand why __fcntl_compat is there. We have >> F_GETFD, F_SETFD, F_DUPFD, F_DUP2FD, F_GETFL, F_SETFL, F_GETOWN, >> and F_SETOWN according to fcntl(2). But thr_syscalls.c only >> handles F_DUPFD, F_SETFD, F_SETFL, F_GETFD, and F_GETFL, leaving >> F_DUP2FD, F_GETOWN, and F_SETOWN to be handled by the default >> case. And the default case does nothing now if WITHOUT_SYSCALL_COMPAT >> is defined. So how do F_DUP2FD, F_GETOWN, and F_SETOWN get >> handled? >> >> Do we really need to call __sys_fcntl_compat() from libthr? >> When did the ABI change, before or after libc.so.7? >> > > I don't know when it appeared. Would this patch eliminate the shit ? I think so. But I think for future ABI changes to cancellation points, wouldn't we need syscall wrappers in libc? Reason, libc and libthr are now symbol-versioned, so there will no longer be library bumps for ABI changes. But if a syscall is a cancellation point and libthr has to play games with it, like fcntl, I think there should be a wrapper around it in libc. If the ABI changes, then both libc and libthr would need to provide a compat version for it. I think. ;-) -- DE
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