Re: [PATCH bpf] libbpf: fix version identification on busybox

[Ivan Khoronzhuk]

On Thu, Sep 19, 2019 at 07:05:18PM +0300, Ivan Khoronzhuk wrote:
> It's very often for embedded to have stripped version of sort in
> busybox, when no -V option present. It breaks build natively on target
> board causing recursive loop.
>
> BusyBox v1.24.1 (2019-04-06 04:09:16 UTC) multi-call binary. \
> Usage: sort [-nrugMcszbdfimSTokt] [-o FILE] [-k \
> start[.offset][opts][,end[.offset][opts]] [-t CHAR] [FILE]...
>
> Lets modify command a little to avoid -V option.
>
> Fixes: dadb81d0afe732 ("libbpf: make libbpf.map source of truth for libbpf version")
>
> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
> ---
>
> Based on bpf/master
>
> tools/lib/bpf/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
> index c6f94cffe06e..a12490ad6215 100644
> --- a/tools/lib/bpf/Makefile
> +++ b/tools/lib/bpf/Makefile
> @@ -3,7 +3,7 @@
>
> LIBBPF_VERSION := $(shell \
> 	grep -oE '^LIBBPF_([0-9.]+)' libbpf.map | \
> -	sort -rV | head -n1 | cut -d'_' -f2)
> +	cut -d'_' -f2 | sort -r | head -n1)
> LIBBPF_MAJOR_VERSION := $(firstword $(subst ., ,$(LIBBPF_VERSION)))

Also can be replaced a lidder harder, with:

LIBBPFMAP := $(shell cat libbpf.map)
LIBBPF_VERSIONS := $(sort $(patsubst %;,%,$(patsubst LIBBPF_%,%,$(filter LIBBPF_%, $(LIBBPFMAP)))))
LIBBPF_VERSION := $(word $(words $(LIBBPF_VERSIONS)), $(LIBBPF_VERSIONS))

You choose, I'm not sure in "sort" of make the same on all systems.

> MAKEFLAGS += --no-print-directory
> --
> 2.17.1

--
Regards,
Ivan Khoronzhuk