cpio includes the number of directory hard links in archives it creates.
Some filesystems, like btrfs, do not count directory hard links the same
way as more common filesystems like ext4 or tmpfs, so archives built
when /tmp is on such a filesystem do not reproduce. This patch replaces
cpio with bsdtar, which does not have this issue. The specific
invocation is from this page:
https://reproducible-builds.org/docs/archives/
- Generate a link to the initramfs file with an appropriate file
extension, guessed based on the compressor by default
- Use correct metadata in u-boot images if generated, up to now this
was hardcoded to gzip and would silently generate an erroneous image
if another compressor was specified
- Document all the parameters
- Improve cross-building compatibility, by allowing passing either a
string as before, or a function taking a package set and returning the
path to a compressor in the "compressor" argument of the
function.
- Support more compression algorithms
- Place compressor executable function and arguments in passthru, for
reuse when appending initramfses
Co-Authored-By: Dominik Xaver Hörl <hoe.dom@gmx.de>
To achieve reproducible results, `cpio` archive members are added in
sorted order and inodes renumbered.
The `cpio-clean.pl` script is made obsolete by setting mtimes via
`touch` & using `cpio --reproducible`. Suggested by @dezgeg in
https://github.com/NixOS/nixpkgs/pull/21273#issuecomment-268116605.
Note that using `--reproducible` means that initial ramdisk creation now
requires at least `cpio` version 2.12 (released in 2015).
This comes from:
svn diff ^/nixpkgs/trunk/@18255 ^/nixpkgs/branches/stdenv-updates/ > diff
patch -p0 < diff
and then adding into svn all files new from the patch.
trunk@18255 comes from the last time I updated stdenv-updates from trunk.
svn path=/nixpkgs/stdenv-updates2/; revision=18272
