Re: [PATCH RESEND 1/1] check-uapi: Introduce check-uapi.sh

[John Moon]

On 2/18/2023 9:25 PM, Masahiro Yamada wrote:
> On Sat, Feb 18, 2023 at 5:23 AM John Moon <quic_johmoo@xxxxxxxxxxx> wrote:
> > While the kernel community has been good at maintaining backwards
> > compatibility with kernel UAPIs, it would be helpful to have a tool
> > to check if a patch introduces changes that break backwards
> > compatibility.
> >
> > To that end, introduce check-uapi.sh: a simple shell script that
> > checks for changes to UAPI headers using libabigail.
> >
> > libabigail is "a framework which aims at helping developers and
> > software distributors to spot some ABI-related issues like interface
> > incompatibility in ELF shared libraries by performing a static
> > analysis of the ELF binaries at hand."
> >
> > The script uses one of libabigail's tools, "abidiff", to compile the
> > changed header before and after the patch to detect any changes.
> >
> > abidiff "compares the ABI of two shared libraries in ELF format. It
> > emits a meaningful report describing the differences between the two
> > ABIs."
> >
> > Signed-off-by: John Moon <quic_johmoo@xxxxxxxxxxx>
>
>
>
>
> BTW, the patch is prefixed with 'RESEND', but it contains
> several diff lines against the previous submission [1].
>
> People would submit this as v2 with changes mentioned under '---'.

Sorry about that, I'm still learning the etiquette. :)

I will mark the patch rev as v2 after addressing your comments.

> [1]: https://patchwork.kernel.org/project/linux-kbuild/patch/20230217202234.32260-2-quic_johmoo@xxxxxxxxxxx/
>
>
>
>
>
>
> diff --git a/scripts/check-uapi.sh b/scripts/check-uapi.sh
> index 209c6793a4d0..b9cd3a2d7805 100755
> --- a/scripts/check-uapi.sh
> +++ b/scripts/check-uapi.sh
> @@ -3,6 +3,7 @@
>
>   # Script to check a patch for UAPI stability
>   set -o errexit
> +set -o pipefail
>
>   print_usage() {
>          name=$(basename "$0")
> @@ -34,7 +35,7 @@ get_header() {
>
>          if [ ! -x "${KERNEL_SRC}/scripts/unifdef" ]; then
>                  if ! make -C "${KERNEL_SRC}/scripts" unifdef; then
> -                       echo 'error - failed to build required
> dependency "scripts/unifdef"'
> +                       errlog 'error - failed to build required
> dependency "scripts/unifdef"'
>                          exit 1
>                  fi
>          fi
> @@ -111,7 +112,7 @@ check_changed_files() {
>
>          total=$((passed + failed))
>          if [ "$total" -eq 0 ]; then
> -               errlog "No changes to UAPI headers detected"
> +               errlog "No changes to UAPI headers detected in most
> recent commit"
>          else
>                  errlog "${passed}/${total} UAPI header file changes
> are backwards compatible"
>          fi
> @@ -190,16 +191,15 @@ check_deps() {
>                  errlog "error - abidiff not found!"
>                  errlog "Please install abigail-tools (version 1.7 or greater)"
>                  errlog "See:
> https://sourceware.org/libabigail/manual/libabigail-overview.html";
> -               exit 2
> +               exit 1
>          fi
>
> -       local -r abidiff_maj=$("$ABIDIFF" --version | cut -d ' ' -f 2
> | cut -d '.' -f 1)
> -       local -r abidiff_min=$("$ABIDIFF" --version | cut -d ' ' -f 2
> | cut -d '.' -f 1)
> +       read -r abidiff_maj abidiff_min _ < <("$ABIDIFF" --version |
> cut -d ' ' -f 2 | tr '.' ' ')
>          if [ "$abidiff_maj" -lt 1 ] || ([ "$abidiff_maj" -eq 1 ] && [
> "$abidiff_min" -lt 7 ]); then
> -               errlog "error - installed abidiff version too old:
> $("$ABIDIFF" --version)"
> +               errlog "error - abidiff version too old: $("$ABIDIFF"
> --version)"
>                  errlog "Please install abigail-tools (version 1.7 or greater)"
>                  errlog "See:
> https://sourceware.org/libabigail/manual/libabigail-overview.html";
> -               exit 2
> +               exit 1
>          fi
>   }
>
> @@ -220,13 +220,18 @@ main() {
>          check_deps
>
>          tmp_dir=$(mktemp -d)
> -       #trap 'rm -rf $tmp_dir' EXIT
> +       trap 'rm -rf $tmp_dir' EXIT
>
>          if [ -z "$KERNEL_SRC" ]; then
>                  KERNEL_SRC="$(realpath "$(dirname "$0")"/..)"
>          fi
>          export KERNEL_SRC
>
> +       if ! (cd "$KERNEL_SRC" && git rev-parse --is-inside-work-tree
> > /dev/null 2>&1); then
> +               errlog "error - this script requires the kernel tree
> to be initialized with Git"
> +               exit 1
> +       fi
> +
>          export ARCH
>          export CC
>          export CROSS_COMPILE