[Buildroot] [PATCH v3 1/3] autobuild-run: initial implementation of check_reproducibility()
Yann E. MORIN
yann.morin.1998 at free.fr
Thu Jun 13 19:53:34 UTC 2019
Atharva, All,
On 2019-06-11 18:04 +0530, Atharva Lele spake thusly:
> For reproducible builds, we want to find out if there are any differences
> between two builds having the same configuration, and to find the reason behind
> them. The diffoscope tool looks inside different types of files to see where the
> differences lie.
>
> check_reproducibility() runs diffoscope on two output directories which are
> expected in output/images and output/images-1. Since it uses objdump, it needs
> to be provided the cross-compile prefix which is derived from the TARGET_CROSS
> variable.
>
> Since diffoscope may not be installed, we fall back to cmp for byte-by-byte
> comparison. We add diffoscope to list of optional programs to avoid repeated
> checking of its presence.
>
> Signed-off-by: Atharva Lele <itsatharva at gmail.com>
Except for two minor coding rules (see below):
Reviewed-by: Yann E. MORIN <yann.morin.1998 at free.fr>
However, for the future: it would be wonderfull if we could entice the
diffoscope developers to make it possible to use it directly from
python: diffoscope *is* a python module, after all.
However, it is cutrrently not very amenable at being used as a python
object (yet):
diffoscope.main():
https://salsa.debian.org/reproducible-builds/diffoscope/blob/master/diffoscope/main.py#L695
which is a glorified wrapper to diffoscope.run_diffoscope():
https://salsa.debian.org/reproducible-builds/diffoscope/blob/master/diffoscope/main.py#L600
which is itself a further glofied wrapper to diffoscope.compare_root_paths()
and diffoscope.Difference()...
But that's for later.
> ---
> Changes v2 -> v3:
> - Use file size of reproducible_results to check reproducibility status, rather than
> exit status of cmp or diff (suggested by arnout)
> - Rename results file (diffoscope_output.txt -> reproducible_results) to avoid confusion
> - Change handling of diffoscope output text file using with open()
> - Changed commit message to have all necessary info (suggested by arnout)
> - Removed leftover code from when I was using an exception to handle
> diffoscope presense (thanks to arnout)
>
> Changes v1 -> v2:
> - move diffoscope output to results dir (suggested by arnout)
> - fix make printvars call
> - Add diffoscope to DEFAULT_OPTIONAL_PROGS
>
> Signed-off-by: Atharva Lele <itsatharva at gmail.com>
> ---
> scripts/autobuild-run | 39 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 38 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/autobuild-run b/scripts/autobuild-run
> index 190a254..ba5b337 100755
> --- a/scripts/autobuild-run
> +++ b/scripts/autobuild-run
> @@ -204,7 +204,7 @@ def get_branch():
>
> class SystemInfo:
> DEFAULT_NEEDED_PROGS = ["make", "git", "gcc"]
> - DEFAULT_OPTIONAL_PROGS = ["bzr", "java", "javac", "jar"]
> + DEFAULT_OPTIONAL_PROGS = ["bzr", "diffoscope", "java", "javac", "jar"]
>
> def __init__(self):
> self.needed_progs = list(self.__class__.DEFAULT_NEEDED_PROGS)
> @@ -394,6 +394,43 @@ def stop_on_build_hang(monitor_thread_hung_build_flag,
> break
> monitor_thread_stop_flag.wait(30)
>
> +def check_reproducibility(**kwargs):
> + """Check reproducibility of builds
> +
> + Use diffoscope on the built images, if diffoscope is not
> + installed, fallback to cmp
> + """
> +
> + log = kwargs['log']
> + idir = "instance-%d" % kwargs['instance']
> + outputdir = os.path.join(idir, "output")
> + srcdir = os.path.join(idir, "buildroot")
> + reproducible_results = os.path.join(outputdir, "results", "reproducible_results")
> + # Using only tar images for now
> + build_1_image = os.path.join(outputdir, "images-1", "rootfs.tar")
> + build_2_image = os.path.join(outputdir, "images", "rootfs.tar")
> +
> + with open(reproducible_results, 'w') as diff:
> + if kwargs['sysinfo'].has("diffoscope"):
> + # Prefix to point diffoscope towards cross-tools
> + prefix = subprocess.check_output(["make", "O=%s" % outputdir, "-C", srcdir, "printvars", "VARS=TARGET_CROSS"])
> + # Remove TARGET_CROSS= and \n from the string
> + prefix = prefix[13:-1]
> + log_write(log, "INFO: running diffoscope on images")
> + subprocess.call(["diffoscope", build_1_image, build_2_image,
> + "--tool-prefix-binutils", prefix], stdout=diff, stderr=log)
> + else:
> + log_write(log, "INFO: diffoscope not installed, falling back to cmp")
> + subprocess.call(["cmp", "-b", "build_1_image", "build_2_image"], stdout=diff, stderr=log)
> +
They are invisible, but this empty line has 4 spaces.
> + if os.stat(reproducible_results).st_size > 0:
> + log_write(log, "INFO: Build is non-reproducible.")
> + return -1
> +
Ditto.
Regards,
Yann E. MORIN.
> + # rootfs images match byte-for-byte -> reproducible image
> + log_write(log, "INFO: Build is reproducible!")
> + return 0
> +
> def do_build(**kwargs):
> """Run the build itself"""
>
> --
> 2.20.1
>
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