On Thu, Feb 12, Michael Brown wrote:
> On 12/02/15 13:44, Olaf Hering wrote:
> > In the spirit of 335a7ddcd4e2d0faaee6d5b1edf0307dfba3d0e5 ("[build] Sort
> > objects in blib.a") to get reproducible binaries from the very same
> > source on different build hosts, the last missing piece to reach that
> > goal is this code in src/Makefile.housekeeping:
> >
> > ...
> > # Command to generate build ID. Must be unique for each $(BIN)/%.tmp,
> > # even within the same build run.
> > #
> > BUILD_ID_CMD := perl -e 'printf "0x%08x", int ( rand ( 0xffffffff ) );'
> > ...
> > --defsym _build_id=`$(BUILD_ID_CMD)`
> > ...
> >
> > The comment makes it clear: appearently some code out there wants this ever
> > changing build_id. What code is it, what will break if _build_id gets a
> > fixed
> > value, and what can be done to give each object an stable but unique id?
>
> romprefix.S uses it to identify multiple instances of itself (e.g. when a
> multi-port NIC exposes the same ROM via multiple PCI functions), in order to
> share PMM-allocated blocks. mromprefix.S also uses it to locate its own ROM
> image within the borrowed PCI BAR.
>
> For this to work, it is important that different binaries (even if built
> from the same bin/blib.a) will never have the same build ID.
Looks like this issue never moved forward. This solves it for me:
-BUILD_ID_CMD := perl -e 'printf "0x%08x", int ( rand ( 0xffffffff ) );'
+BUILD_ID_CMD := bash -x -c 'declare -i i=1 ; while : ; do dir=$$(printf
0x%08x $$i) ; : $$(( i++ )) ; mkdir "$${dir}" || continue ; echo "$${dir}" ;
break ; done'
I'm sure the shell part can be done in perl as well.
Olaf
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