Steven Chamberlain wrote: > using Helmut's tool, I've been able to rebootstrap a minimal Debian > linux-i386 chroot (445 binary packages[3]). These were cross-compiled > from source, by only running kfreebsd-amd64 binaries on a FreeBSD > kernel, and having some Arch:all packages installed.
I've begun to analyze this now, using diffoscope to compare a stage1 debootstrapped chroot of linux-i386, from official Debian packages vs. my cross-built ones from kfreebsd-amd64. Unfortunately all the ELF binaries have differences, but most other files' contents are reproducible. The biggest problem was that the cross toolchain's linker used a different target ABI: │ │ │ - OS: Linux, ABI: 3.2.0 │ │ │ + OS: Linux, ABI: 2.6.32 and that leads to huge differences in the output binaries, such as not using .init_array/.fini_array sections. That may have consequences, such as if reproducible.debian.net jobs ever override uname to 2.6.x (Bug #806911), we may run into this problem there. umasks are applied to symlinks differently on kfreebsd than on linux: │ │ -lrwxrwxrwx root/root 0 2015-10-28 22:29:08 ./etc/os-release -> ../usr/lib/os-release │ │ +lrwxr-xr-x root/root 0 2015-10-28 22:29:08 ./etc/os-release -> ../usr/lib/os-release base-files seems to look at uname of the build architecture, rather than host arch it is building for: │ ├── ./usr/lib/os-release │ │ @@ -1,6 +1,6 @@ │ │ -PRETTY_NAME="Debian GNU/Linux stretch/sid" │ │ -NAME="Debian GNU/Linux" │ │ +PRETTY_NAME="Debian GNU/kFreeBSD stretch/sid" │ │ +NAME="Debian GNU/kFreeBSD" gzip embeds the version of a build-dependency, makeinfo. That's slightly annoying; it creates differences where there needn't have been otherwise: │ ├── ./usr/share/info/gzip.info.gz │ │ ├── gzip.info │ │ │ @@ -1,2827 +1,2827 @@ │ │ │ 00000000: 5468 6973 2069 7320 677a 6970 2e69 6e66 This is gzip.inf │ │ │ 00000010: 6f2c 2070 726f 6475 6365 6420 6279 206d o, produced by m │ │ │ 00000020: 616b 6569 6e66 6f20 7665 7273 696f 6e20 akeinfo version │ │ │ -00000030: 352e 3220 6672 6f6d 2067 7a69 702e 7465 5.2 from gzip.te │ │ │ +00000030: 362e 3020 6672 6f6d 2067 7a69 702e 7465 6.0 from gzip.te │ │ │ 00000040: 7869 2e0a 0a54 6869 7320 6d61 6e75 616c xi Then I saw some some reproducibility issues that are already known (#774425 in dash, #806328 in xz-utils). Here are my chroots and diffoscope output, in case anyone is curious: http://kfreebsd.eu/rebootstrap/2016010100/native.tar.xz (12MiB) http://kfreebsd.eu/rebootstrap/2016010100/rebootstrap.tar.xz (12MiB) http://kfreebsd.eu/rebootstrap/2016010100/diff.xz (6MiB) Regards, -- Steven Chamberlain ste...@pyro.eu.org
signature.asc
Description: Digital signature
