Date: Fri, 16 Nov 2018 16:38:45 -0500 From: Rich Felker <dalias@...c.org> To: musl@...ts.openwall.com, Paul Sykes <paulsykes@...il.com> Subject: Re: optopt in getopt not being set, only when building with OpenWrt On Fri, Nov 16, 2018 at 10:11:00PM +0100, Szabolcs Nagy wrote: > * Paul Sykes <paulsykes@...il.com> [2018-11-16 17:54:23 +0800]: > > On my OpenWrt builds I found that the optopt variable was never set > > when calling the function getopt. I tested the same code on my desktop > > using the gcc wrapper and optopt was set as expected. > > > > Debugging showed that optopt was being set correctly in getopt.c > > however the variable was not being set in my calling code. > > > > Adding optopt to the file 'dynamic.list' resolved the issue when > > building with OpenWrt. I noticed that all the other extern variables > > for getopt appear in dynamic.list except optopt. Yes, this is exactly right. It seems to have been an oversight. I'll push a fix for inclusion in 1.1.21, and distros using 1.1.20 should apply it since this is a notable regression. However, > yeah the dynamic list entry is needed so the address of the > object internally in the libc is the same as in the main > executable in case of copy relocation (only matters for > dynamic linked executables and pie executable may work > since that does not require copy relocs). > > all targets with copy relocs are affected, but only musl > version 1.1.20 has the problem i think. On distros using default-pie, the impact might be low, depending on arch, gcc version, and CFLAGS. There's never a *need* to use copy relocations with pie, and at one point gcc never did, but I think with current tooling it's more complicated whether copy relocations get used or not. Rich
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