Re: [PATCH v2 1/2] busybox: always start do_compile with orig config files

Re: [PATCH v2 1/2] busybox: always start do_compile with orig config files

[Richard Purdie]

On Mon, 2023-01-09 at 09:04 +0000, Antonin Godard wrote:
> When compiling busybox a second time (e.g. with `compile -f`), busybox
> can use an altered autoconf.h file for compiling, which can ultimately
> produces different and unwanted binaries.
> 
> This can produce errors like this one:
> 
> ERROR: busybox-1.35.0-r0 do_package: Error executing a python function in exec_func_python() autogenerated:
> The stack trace of python calls that resulted in this exception/failure was:
> File: 'exec_func_python() autogenerated', lineno: 2, function: <module>
>      0001:
>  *** 0002:ptest_update_alternatives(d)
>      0003:
> File: '…/poky/meta/classes/ptest.bbclass', lineno: 100, function: ptest_update_alternatives
>      0096:        for alt_name, alt_link, alt_target, _ in alternatives:
>      0097:            # Some alternatives are for man pages,
>      0098:            # check if the alternative is in PATH
>      0099:            if os.path.dirname(alt_link) in bin_paths:
>  *** 0100:                os.symlink(alt_target, os.path.join(ptest_bindir, alt_name))
>      0101:}
>      0102:
>      0103:do_configure_ptest_base[dirs] = "${B}"
>      0104:do_compile_ptest_base[dirs] = "${B}"
> Exception: FileExistsError: [Errno 17] File exists: '/bin/busybox.suid' -> '…/busybox/1.35.0-r0/package/usr/lib/busybox/ptest/bin/login'
> 
> This happens because ALTERNATIVE:busybox contains `/bin/login` twice,
> initially that's because `/bin/login` is present in both
> busybox.links.suid and busybox.links.nosuid. The reason for that is
> because of the altered autoconf.h.
> 
> Steps to reproduce above error:
> 
> <add ptest to distro configs>
> bitbake busybox -c clean
> bitbake busybox -c package -f
> bitbake busybox -c compile -f
> bitbake busybox -c package -f
> 
> This patch guards against potential bugs by:
> 
> - making a backup of .config and autoconf.h that have matching
>   timestamps.
> - make sure do_compile always starts with these files.
> - restore .config and autoconf.h at the end of do_compile.

Thanks for tweaking these, I think that should fix a few more possible
race issues. They passed testing and have merged.

Cheers,

Richard