From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/6190 Path: news.gmane.org!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: compiling musl on x86_64 linux with pcc Date: Tue, 23 Sep 2014 15:31:34 -0400 Message-ID: <20140923193134.GL23797@brightrain.aerifal.cx> References: <20140813091843.GD5170@example.net> <20140813123832.GK12888@brightrain.aerifal.cx> <20140813125607.GK5170@example.net> <20140813142332.GN12888@brightrain.aerifal.cx> <20140825082807.GB12376@example.net> <20140825083457.GC12376@example.net> <20140825154617.GV12888@brightrain.aerifal.cx> <20140923190525.GJ13475@example.net> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1411500716 12627 80.91.229.3 (23 Sep 2014 19:31:56 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 23 Sep 2014 19:31:56 +0000 (UTC) Cc: musl@lists.openwall.com To: u-igbb@aetey.se Original-X-From: musl-return-6203-gllmg-musl=m.gmane.org@lists.openwall.com Tue Sep 23 21:31:51 2014 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1XWVoU-00063f-Cv for gllmg-musl@plane.gmane.org; Tue, 23 Sep 2014 21:31:50 +0200 Original-Received: (qmail 28038 invoked by uid 550); 23 Sep 2014 19:31:49 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 28026 invoked from network); 23 Sep 2014 19:31:49 -0000 Content-Disposition: inline In-Reply-To: <20140923190525.GJ13475@example.net> User-Agent: Mutt/1.5.21 (2010-09-15) Original-Sender: Rich Felker Xref: news.gmane.org gmane.linux.lib.musl.general:6190 Archived-At: On Tue, Sep 23, 2014 at 09:05:25PM +0200, u-igbb@aetey.se wrote: > On Mon, Aug 25, 2014 at 11:46:17AM -0400, Rich Felker wrote: > > Note that some fixes are needed for > > pcc-libs: > > > > - You need to remove the broken csu files and replace them with > > symlinks to the musl files. > > > > - You need to add __attribute__((__visibility__("hidden"))) to all > > external functions in libpcc. > > > > - You need to add -fPIC to the CFLAGS for building libpcc or you get a > > broken libpcc (containing textrels) that can't be used for building > > libc.so and that's harmful for use with any other shared libs. > > I followed these directions and musl with pcc play along very well for me > (on i386). > > One strange thing I notice though, which is probably more pcc-related > than musl (even though this concerns a musl-based toolchain). > > If I build a shared library with pcc without supplying -Wl,-Bsymbolic > (or -Wl,-Bsymbolic-functions as musl does) then a(ny) binary linked to that > library segfaults at start even if it does not actually need/use the > library. I noticed this with libpcap and wonder what is the reason. Adding > -Wl,-Bsymbolic makes everything work so the code is not exactly broken. > > Wonder if you happen to guess a possible reason for such kind of trouble, > something that pcc gets wrong? This looks related to runtime linking > behaviour so possibly not fully offtopic here. Have you checked that this happens with all libs, or did you only observe it with libpcap? If you have a minimal example .so file that causes the crash when loaded, can you post it somewhere I could download a copy to analyze, and also post the commands you used to produce it? Rich