Unlike SYSLINUX, GRUB2 does not recommend embedding itself in a FAT
filesystem. Instead GRUB2 prefers embedding in the space between the MBR
and first partition or using a dedicated partition that is safe from
tampering by fs utilities. In our case the space after the MBR is where
the GPT lives so we need to use the extra partition scheme instead.
The 64MB "BOOT-B" partition has never been used so we can replace it
with a 2MB partition which is more than enough for GRUB.
We have long since stopped installing anything to the /boot directory of
the root filesystem. Mount the ESP partition to /boot for consistancy
with the discoverable partition spec.
Normally GCC is installed in a way that allows installing multiple
versions and switching between them. Our production images do not need
this and additionally the only things from the GCC package that are
needed are the shared libraries. To ensure these libraries are *always*
locatable regardless of the presence of /etc/ld.so.conf and
/etc/ld.so.cache we can install those libraries to plain old /usr/lib.
The GCC packages don't have a built in way to do this but we can get
away with extracting the libraries directly from the binary package.
This is actually similar to what ChromeOS did with a few exceptions:
- We use a native GCC build instead of the cross toolchain
- The archive is properly extracted from the package instead of feeding
the package directly to tar and ignoring the resulting warnings.
As an added benefit switching from a blacklist to a whitelist ensures
that extra cruft does not slip through the cracks, saving 5-10MB.
Create profile as a real directory instead of a symlink to the board
root's configuration. Normally the board root does not modify this but
it is useful for build_image to use it to modify package.provided.
Normally Gentoo expects moving between major GCC releases to be a manual
step. In our case we want this to always be automatic, otherwise the GCC
version won't be switched at all.
Apparently expanding an empty string before a variable assignment forces
that assignment to be interpreted as a command instead. Instead of an
empty string use env as our sudo alternative when running as root.
Newer git ebuilds have decided that the "git-prompt" script isn't really
bash completion so stopped installing it via that mechanism. Instead it
installed it started installing it in /usr/share/docs which gets
compressed by default and the path is based on ebuild version. The path
changed again in 1.9.3 to /usr/share/git and didn't compress it so that
makes it actually possibly usable but 1.9.3 or later isn't stable yet.
We can re-enable it the next time git gets updated but not worth fussing
over the current brokenness right now.
If additional EBS volumes are mapped to a PV instance using a "sd*" name
they will always be ordered by the hypervisor before "xvd*" devices,
again ignoring the root device definition. This applies to all PV
instance types so we cannot get away with just poo-pooing m1.small.
We will need to call attention to this since it requires users who set
the volume size via APIs to use the name "/dev/sda" again.
For a long time these scripts have always set images as public
regardless of whether the image was a working production image or not.
This may lead users to boot random development images if they happen to
pop up to the top of Amazon's terrible AMI search page.
If util-linux has a binary package it will be used, but if that binary
package has +udev it will pull in systemd. systemd has a loop that needs
to be broken too so if the util-linux loop breaker doesn't also handle
the systemd one it all falls apart.
In short the comment above the loop breaker code noting that we can try
this until it gets wonky. Well, it is wonky and we need to re-do how
build_packages works as a result. This is just a temporary workaround
until we figure out a larger restructuring.
Fix 98684560 which in turn tried to fix 0d29e735. This time the option
to download binary packages was lost so building from scratch worked but
not the normal usage of using binary packages. *sigh*
