Date: Mon, 09 Mar 2009 14:02:23 +0800 From: David Xu <davidxu@freebsd.org> To: Daniel Eischen <deischen@freebsd.org> Cc: threads@freebsd.org, Pawel Worach <pawel.worach@gmail.com> Subject: Re: libthr does not obey WITHOUT_SYSCALL_COMPAT Message-ID: <49B4B0EF.5080507@freebsd.org> In-Reply-To: <Pine.GSO.4.64.0903090114380.8422@sea.ntplx.net> References: <d227e09e0903041123i638a12b8m5d8573cc871d1533@mail.gmail.com> <49B480F7.8040800@freebsd.org> <Pine.GSO.4.64.0903082343280.8064@sea.ntplx.net> <49B4A571.7000302@freebsd.org> <Pine.GSO.4.64.0903090114380.8422@sea.ntplx.net>
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Daniel Eischen wrote: > 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. ;-) > Yes, it is better to use versioning instead, I don't know why fcntl_compat is there without using this feature.
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