`awk` is already required by the kernel build, and the `xargs` feature
used in current Rust detection is not present in all `xargs` (notably,
toybox based xargs, used in the Android kernel build).

Signed-off-by: Matthew Maurer <mmaurer@google.com>
---
 rust/Makefile | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index 87958e864be0..0efc5b5cd611 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -365,8 +365,7 @@ quiet_cmd_exports = EXPORTS $@
       cmd_exports = \
 	$(NM) -p --defined-only $< \
 		| grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \
-		| xargs -Isymbol \
-		echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@
+		| awk 'NF {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$0}' > $@
 
 $(obj)/exports_core_generated.h: $(obj)/core.o FORCE
 	$(call if_changed,exports)
-- 
2.42.0.582.g8ccd20d70d-goog

On Thu, 2023-09-28 at 20:21 +0000, Matthew Maurer wrote:
> `awk` is already required by the kernel build, and the `xargs` feature
> used in current Rust detection is not present in all `xargs` (notably,
> toybox based xargs, used in the Android kernel build).
[]
> diff --git a/rust/Makefile b/rust/Makefile
[]
> @@ -365,8 +365,7 @@ quiet_cmd_exports = EXPORTS $@
>        cmd_exports = \
>  	$(NM) -p --defined-only $< \
>  		| grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \
> -		| xargs -Isymbol \
> -		echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@
> +		| awk 'NF {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$0}' > $@

Perhaps remove the cut as well and use $$3 instead of $$0 ?
Maybe integrate the grep as well.

From: Joe Perches
> Sent: 28 September 2023 21:33
> 
> On Thu, 2023-09-28 at 20:21 +0000, Matthew Maurer wrote:
> > `awk` is already required by the kernel build, and the `xargs` feature
> > used in current Rust detection is not present in all `xargs` (notably,
> > toybox based xargs, used in the Android kernel build).
> []
> > diff --git a/rust/Makefile b/rust/Makefile
> []
> > @@ -365,8 +365,7 @@ quiet_cmd_exports = EXPORTS $@
> >        cmd_exports = \
> >  	$(NM) -p --defined-only $< \
> >  		| grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \
> > -		| xargs -Isymbol \
> > -		echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@
> > +		| awk 'NF {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$0}' > $@
> 
> Perhaps remove the cut as well and use $$3 instead of $$0 ?
> Maybe integrate the grep as well.

Or keep the grep and use a shell loop?
	grep -E ' (T|R|D) ' | while read val flag symbol; do \
		echo "EXPORT_SYMBOL_RUST_GPL($symbol);"; done

(The grep is typically much faster than a shell conditional.)

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

On Fri, 2023-09-29 at 21:36 +0000, David Laight wrote:
> From: Joe Perches
> > Sent: 28 September 2023 21:33
> > 
> > On Thu, 2023-09-28 at 20:21 +0000, Matthew Maurer wrote:
> > > `awk` is already required by the kernel build, and the `xargs` feature
> > > used in current Rust detection is not present in all `xargs` (notably,
> > > toybox based xargs, used in the Android kernel build).
> > []
> > > diff --git a/rust/Makefile b/rust/Makefile
> > []
> > > @@ -365,8 +365,7 @@ quiet_cmd_exports = EXPORTS $@
> > >        cmd_exports = \
> > >  	$(NM) -p --defined-only $< \
> > >  		| grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \
> > > -		| xargs -Isymbol \
> > > -		echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@
> > > +		| awk 'NF {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$0}' > $@
> > 
> > Perhaps remove the cut as well and use $$3 instead of $$0 ?
> > Maybe integrate the grep as well.
> 
> Or keep the grep and use a shell loop?
> 	grep -E ' (T|R|D) ' | while read val flag symbol; do \
> 		echo "EXPORT_SYMBOL_RUST_GPL($symbol);"; done
> 
> (The grep is typically much faster than a shell conditional.)
> 

Bikeshed:

no grep just a single awk with whatever the appropriate syntax is like

awk '{ if ($$2 ~ /^[TRD]$/) { printf "EXPORT_SYMBOL_RUST(%s);\n", $$3 } }'