Date: Fri, 21 Apr 2006 10:39:03 +0200 From: Jeremie Le Hen <jeremie@le-hen.org> To: Kostik Belousov <kostikbel@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: [fbsd] Re: [fbsd] Re: Symbol weirdness with static linking Message-ID: <20060421083903.GE68951@obiwan.tataz.chchile.org> In-Reply-To: <20060421080216.GB1446@deviant.kiev.zoral.com.ua> References: <20060420114822.GB35261@obiwan.tataz.chchile.org> <20060420124829.GA1446@deviant.kiev.zoral.com.ua> <20060420221623.GD68951@obiwan.tataz.chchile.org> <20060421080216.GB1446@deviant.kiev.zoral.com.ua>
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Kostik, On Fri, Apr 21, 2006 at 11:02:17AM +0300, Kostik Belousov wrote: > > > It seems that you rebuilt world with CFLAGS -fstack-protector, > > > since your libc has references to the symbols like __stack_smash_handler. > > > As result, when linking with sequence -lgcc -lssp -lc -lgcc -lssp, > > > and no references from the main object, > > > references from libc causes objects from _second_ instance of -lssp to > > > be pulled into the link. Since libraries are scanned sequentially, > > > this object from libssp has no way to get required dependencies > > > from libc. > > > > Yes, I understand that. But I can't see what's the difference between > > "syslog" and "sigfillset" symbols from this standpoint. The fact the > > former requires ProPolice/SSP doesn't interfere IMHO. > > > > > What makes syslog(3) special is that corresponding object from libc, > > > syslog.o, requires __stack_smash_handler, while objects for mentioned > > > syscalls do not. > > > > How does it prevent the "syslog" symbol from being found ? Libc > > undefined symbols implies the second libssp to be pulled in which in > > turn has undefined symbol. But since there is no more libc after this, > > "sigfillset" should be missing either. > > > > I would understand if echo.o needed some symbols provided by the same > > archive than "sigfillset" (sigsetops.o) but this is not the case. > > > You are absolutely right, my error. "Explanation" with syslog dependency > on stack_smash is wrong. In fact, building bin/echo on CURRENT with > -DNO_SHARED gives > > deviant% objdump -t echo | grep sigfillset > 08056dc0 g F .text 00000021 sigfillset > > It seems that at least the following dependency > chain is present (for 6-STABLE): > > malloc -> abort -> sigfillset, > > and malloc is referenced by echo. > > For CURRENT, (possibly, another) dependency also pulls > sig* from libc. > > Sorry for misinformation, I was innacurate when looking at issue. There is no harm, don't bother. I made me think some more on linking mechanisms and I am more familiar with it now. Thank you very much for your explanation. Best regards, -- Jeremie Le Hen < jeremie at le-hen dot org >< ttz at chchile dot org >
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