On 2020-06-20 16:58 -0500, Bruce Dubbs via lfs-dev wrote: > On 6/20/20 2:42 PM, Xi Ruoyao via lfs-dev wrote: > > The discussion with Frans de Boer in lfs-support shown that the environment > > variables from host can catch us completely off guard. Though in his case > > the > > problem is that he forgot to create /home/lfs/.bash_profile, normally > > /etc/bash.bashrc would be more dangerous (the book has no consideration of > > this > > file), and used by many distros. > > > > So if there is no objection I'll commit the change we've discussed in last > > Nov.: > > > > /home/lfs/.bash_profile: > > > > exec env -i ENV=$HOME/.lfs_bashrc \ > > HOME=$HOME \ > > TERM=$TERM \ > > PS1='\u:\w\$ ' \ > > /bin/bash --posix > > > > /home/lfs/.lfs_bashrc: > > > > set +o posix > > set +h > > umask 022 > > LFS=/mnt/lfs > > LC_ALL=POSIX > > LFS_TGT=$(uname -m)-lfs-linux-gnu > > PATH=/usr/bin > > if [ ! -L /bin ]; then PATH=/bin:$PATH; fi > > PATH=$LFS/tools/bin:$PATH > > export LFS LC_ALL LFS_TGT PATH > > So the --posix in .bash_profile allows the use of > ENV=$HOME/.lfs_bashrc and then the first line in .lfs_bashrc turns posix > mode off? > > At a minimum this looks like a hack that needs a fair amount of explanation. > > The reason for this is because a user forgot to create .bash_profile? > In that case the above doesn't work.
The discussion just proved that environment variables from host are really harmful. > From https://sources.debian.org/src/bash/5.0-6/debian/README/ > > 5. What is /etc/bash.bashrc? It doesn't seem to be documented. > > The Debian version of bash is compiled with a special option > (-DSYS_BASHRC) that makes bash read /etc/bash.bashrc before ~/.bashrc > for interactive non-login shells. So, on Debian systems, > /etc/bash.bashrc is to ~/.bashrc as /etc/profile is to > ~/.bash_profile. > > When I look at a debian system's /etc/bash.bashrc, I don't see what > would affect what we have now. What was the reported problem? > > We've been using the current structure for a long time without a > reported issue. What's new? I studied OpenSUSE bash.bashrc a little. It's a giant monster script (even sourcing some scripts from /etc/profile.d) so I won't be suprised if one day a bash.bashrc breaks some package. And after a sleep I realized a more serious issue: if some distro has a /usr/share/config.site (or /usr/etc/config.site, which is not FHS and shouldn't exist), it would be used by autotools configure script *even if we are cross compiling*, and break temporary glibc build. Perhaps we should "export CONFIG_SITE=/dev/null" in /home/lfs/.bashrc to override it. -- Xi Ruoyao <xry...@mengyan1223.wang> School of Aerospace Science and Technology, Xidian University -- http://lists.linuxfromscratch.org/listinfo/lfs-dev FAQ: http://www.linuxfromscratch.org/faq/ Unsubscribe: See the above information page
