sys/conf: Remap paths for reproducibility
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Authored by markj on Jun 20 2025, 5:13 PM.

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emaste
brooks
bnovkov
kevans
imp

Commits

rG18a65998107a: sys/conf: Remap paths for reproducibility
rGeebadc7d8590: sys/conf: Remap paths for reproducibility

Summary

As in bsd.lib.mk and bsd.prog.mk, we need to remap paths in the kernel
and in kernel modules when reproducible builds are configured. Add
directives to kern.post.mk and kmod.mk to remap the src, obj and sysroot
dirs.

For the sysroot, we need to pass the value of the SYSROOT variable to
the kernel makefiles, which involves changing Makefile.inc1. In so
doing I reverted a portion of commit 35fb812adfc21; I can't see any harm
in passing the SYSROOT variable down.

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Repository

rG FreeBSD src repository

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Build Status

Buildable 64997
Build 61880: arc lint + arc unit

Event Timeline

markj requested review of this revision.Jun 20 2025, 5:13 PM

markj created this revision.

markj added a parent revision: D50952: kerberos5: Avoid embedding full paths in generated files.

Harbormaster completed remote builds in B64997: Diff 157387.Jun 20 2025, 5:13 PM

markj added a child revision: D50954: newvers: Add a builddir parameter.Jun 20 2025, 5:13 PM

I think this is directionally the right way to do but haven't had a chance to take a detailed look. I don't like that we have duplicated logic in several places and have been pondering whether there's a way to avoid it, but don't have a good idea off hand.

emaste mentioned this in D50951: share/mk: Substitute reproducible prefixes in dwarf info.Aug 6 2025, 12:22 AM

In D50953#1182192, @emaste wrote:

I think this is directionally the right way to do but haven't had a chance to take a detailed look. I don't like that we have duplicated logic in several places and have been pondering whether there's a way to avoid it, but don't have a good idea off hand.

To be clear, this logic isn't totally duplicated. The handling of KERNBUILDDIR is specific to kmod.mk, and the canonical objdir is different between the kernel and kernel modules. If anything, it makes some sense to have separate blocks for handling the kernel vs. kernel modules since the two are built quite differently.

The distinction in the bsd.prog.mk/bsd.lib.mk is less useful, I agree. There I'll see if I can factor the duplication into a bsd.debug.mk or so.

This revision was not accepted when it landed; it landed in state Needs Review.Aug 21 2025, 3:58 PM

Closed by commit rGeebadc7d8590: sys/conf: Remap paths for reproducibility (authored by markj). · Explain Why

This revision was automatically updated to reflect the committed changes.

markj added a commit: rGeebadc7d8590: sys/conf: Remap paths for reproducibility.

markj added a commit: rG18a65998107a: sys/conf: Remap paths for reproducibility.Sep 30 2025, 9:15 PM