Re: [gentoo-catalyst] How is initrd built?

[Paul Smith]

%% I wrote:

  sp> So, the next problem is that after the init is done and the system
  sp> starts to boot, various things fail because /etc/fstab is empty.

  sp> I don't see anywhere in the "normal" boot process that /etc/fstab is
  sp> built... am I missing something?  Is it as simple as "cp /proc/mounts
  sp> $CHROOT/etc/fstab"?

OK, I found this problem.  This code in linuxrc in genkernel is bogus:

    cat /${UNION}/etc/fstab | sed -e 's|\(.*\s/\s*tmpfs\s*\)defaults\(.*\)|\1defaults,ro\2|' > /${UNION}/etc/fstab

We are cat'ing a file in a pipeline, and redirecting the output back to
that same file; that is not safe.  In fact, sometimes when I run this it
works but most of the time I get a zero-length fstab file.  When I get an
empty file the normal boot fails because it tries to do invalid things
like remount the union filesystem, which is not supported.

This is fixed easily enough by using sed -i instead:

    sed -i -e 's|\(.*\s/\s*tmpfs\s*\)defaults\(.*\)|\1defaults,ro\2|' /${UNION}/etc/fstab

However, it's actually not really clear to me what this is trying to do.
The comment is at best very confusing to me:

    # Make sure fstab notes livecd is mounted ro.  Makes system skip remount which fails on unionfs dirs.

The above sed doesn't touch anything related to livecd; it's managing
"/", which will be (when we chroot) the unionfs.  And, why changing it
to say "ro" in /etc/fstab will STOP the system from trying to remount it
"rw" is really a mystery to me...??

-- 
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 Paul D. Smith <psmith@××××××.com>           HASMAT--HA Software Mthds & Tools
 "Please remain calm...I may be mad, but I am a professional." --Mad Scientist
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