On Mon, Sep 02, 2024 at 06:08:28PM +0200, Miguel Ojeda wrote:
> Like patch "rust: suppress error messages from
> CONFIG_{RUSTC,BINDGEN}_VERSION_TEXT" [1], do not assume the file existing
> and being executable implies executing it will succeed.
>
> Instead, bail out if executing it fails for any reason, as well as if
> the program does not print to standard output what we are expecting from
> `pahole --version`. The script needs to ensure that it always returns
> an integer, since its output will go into a Kconfig `int`-type symbol.
>
> In addition, check whether the program exists first, and provide
> error messages for each error condition, similar to how it is done in
> e.g. `scripts/rust_is_available.sh`.
>
> For instance, currently `pahole` may be built for another architecture
> or may be a program we do not expect that fails:
>
> $ echo 'bad' > bad-pahole
> $ chmod u+x bad-pahole
> $ make PAHOLE=./bad-pahole defconfig
> ...
> ./bad-pahole: 1: bad: not found
> init/Kconfig:112: syntax error
> init/Kconfig:112: invalid statement
>
> With this applied, we get instead:
>
> ***
> *** Running './bad-pahole' to check the pahole version failed with
> *** code 127. pahole will not be used.
> ***
> ...
> $ grep CONFIG_PAHOLE_VERSION .config
> CONFIG_PAHOLE_VERSION=0
>
> Similarly, `pahole` currently may be a program that returns successfully,
> but that does not print the version that we would expect:
>
> $ echo 'echo' > bad-pahole
> $ chmod u+x bad-pahole
> $ make PAHOLE=./bad-pahole defconfig
> ...
> init/Kconfig:114: syntax error
> init/Kconfig:114: invalid statement
>
> With this applied, we get instead:
>
> ***
> *** pahole './bad-pahole' returned an unexpected version output.
> *** pahole will not be used.
> ***
> ...
> $ grep CONFIG_PAHOLE_VERSION .config
> CONFIG_PAHOLE_VERSION=0
>
> Finally, with this applied, if the program does not exist, we get:
>
> $ make PAHOLE=./bad-pahole defconfig
> ...
> ***
> *** pahole './bad-pahole' could not be found. pahole will not be used.
> ***
> ...
> $ grep CONFIG_PAHOLE_VERSION .config
> CONFIG_PAHOLE_VERSION=0
>
> Link: https://lore.kernel.org/rust-for-linux/20240727140302.1806011-1-masahiroy@xxxxxxxxxx/ [1]
> Co-developed-by: Nicolas Schier <nicolas@xxxxxxxxx>
> Signed-off-by: Nicolas Schier <nicolas@xxxxxxxxx>
> Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
> ---
> v1: https://lore.kernel.org/all/20240728125527.690726-1-ojeda@xxxxxxxxxx/
> v2:
>
> Reworked to catch successful programs that may not output what we expect from
> pahole as well as to do the checking step-by-step (for better error messages).
>
> I didn't change the regular expression to reduce the changes (except adding
> `p`) -- it can be improved separately.
>
> Also, please note that I added Nicolas as co-author since he proposed part of
> the solution, but he has not formally signed off yet.
thanks, no objections.
> scripts/pahole-version.sh | 30 +++++++++++++++++++++++++++---
> 1 file changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/pahole-version.sh b/scripts/pahole-version.sh
> index f8a32ab93ad1..cdb80a3d6e4f 100755
> --- a/scripts/pahole-version.sh
> +++ b/scripts/pahole-version.sh
> @@ -5,9 +5,33 @@
> #
> # Prints pahole's version in a 3-digit form, such as 119 for v1.19.
>
> -if [ ! -x "$(command -v "$@")" ]; then
> - echo 0
> +set -e
> +trap "echo 0; exit 1" EXIT
> +
> +if ! command -v "$@" >/dev/null; then
> + echo >&2 "***"
> + echo >&2 "*** pahole '$@' could not be found. pahole will not be used."
shellcheck likes to have '$*' instead of '$@', but I can't think of a
set of arguments which might cause problems.
> + echo >&2 "***"
> + exit 1
> +fi
> +
> +output=$("$@" --version 2>/dev/null) || code=$?
> +if [ -n "$code" ]; then
> + echo >&2 "***"
> + echo >&2 "*** Running '$@' to check the pahole version failed with"
> + echo >&2 "*** code $code. pahole will not be used."
> + echo >&2 "***"
> + exit 1
> +fi
> +
> +output=$(echo "$output" | sed -nE 's/v([0-9]+)\.([0-9]+)/\1\2/p')
I'd rather like to have
output=$(echo "$output" | sed -nE 's/v([0-9]+)\.([0-9][0-9])/\1\2/p')
here (thus, explicitly check against a two number subversion), so that
we can detect also versions like 1.100 or 2.1 and bail out.
Kind regards,
Nicolas
