klibc - Jul 2020 - [PATCH] klcc: Remove the need for bash

Currently, in the entire klibc bash is only used to identify the path of
the perl binary. It is doing so using the bash built-in 'type' function,
which is POSIX compliant according to [0], but the option -c is not.

By using `command -v` instead, we achieve the same result, in a POSIX
compliant manor [1], potentially removing the unneeded bash dependency.

0 https://www.unix.com/man-page/posix/1p/type/
1 https://www.unix.com/man-page/posix/1p/command/

Signed-off-by: Olliver Schinagl <oliver at schinagl.nl>
---
 klcc/Kbuild | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/klcc/Kbuild b/klcc/Kbuild
index eae753ff..0e625802 100644
--- a/klcc/Kbuild
+++ b/klcc/Kbuild
@@ -35,7 +35,7 @@ targets := $(KLIBCCROSS)klcc
 quiet_cmd_klcc = GEN     $@
       cmd_klcc = $(PERL) $< $(srctree)/$(src)/klcc.in \
                             $(obj)/$(KLIBCCROSS)klibc.config \
-                            $(shell bash -c 'type -p $(PERL)') \
+                            $(shell command -v $(PERL)) \
 			      > $@ || ( rm -f $@ ; exit 1 ) && \
 			      chmod a+x $@
 $(obj)/$(KLIBCCROSS)klcc: $(src)/makeklcc.pl $(src)/klcc.in \
-- 
2.27.0

On Sat, 2020-07-25 at 10:59 +0200, Olliver Schinagl
wrote:
> Currently, in the entire klibc bash is only used to identify the path of
> the perl binary. It is doing so using the bash built-in 'type'
function,
> which is POSIX compliant according to [0], but the option -c is not.
> 
> By using `command -v` instead, we achieve the same result, in a POSIX
> compliant manor [1], potentially removing the unneeded bash dependency.
> 
> 0 https://www.unix.com/man-page/posix/1p/type/
> 1 https://www.unix.com/man-page/posix/1p/command/
> 
> Signed-off-by: Olliver Schinagl <oliver at schinagl.nl>
Applied, thanks.

Ben.
> ---
>  klcc/Kbuild | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/klcc/Kbuild b/klcc/Kbuild
> index eae753ff..0e625802 100644
> --- a/klcc/Kbuild
> +++ b/klcc/Kbuild
> @@ -35,7 +35,7 @@ targets := $(KLIBCCROSS)klcc
>  quiet_cmd_klcc = GEN     $@
>        cmd_klcc = $(PERL) $< $(srctree)/$(src)/klcc.in \
>                              $(obj)/$(KLIBCCROSS)klibc.config \
> -                            $(shell bash -c 'type -p $(PERL)') \
> +                            $(shell command -v $(PERL)) \
>  			      > $@ || ( rm -f $@ ; exit 1 ) && \
>  			      chmod a+x $@
>  $(obj)/$(KLIBCCROSS)klcc: $(src)/makeklcc.pl $(src)/klcc.in \
-- 
Ben Hutchings
Theory and practice are closer in theory than in practice - John Levine


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Ben Hutchings <ben at decadent.org.uk> wrote:
> On Sat, 2020-07-25 at 10:59 +0200, Olliver Schinagl wrote:
>> Currently, in the entire klibc bash is only used to identify the path
of
>> the perl binary. It is doing so using the bash built-in 'type'
function,
>> which is POSIX compliant according to [0], but the option -c is not.
>> 
>> By using `command -v` instead, we achieve the same result, in a POSIX
>> compliant manor [1], potentially removing the unneeded bash dependency.
>> 
>> 0 https://www.unix.com/man-page/posix/1p/type/
>> 1 https://www.unix.com/man-page/posix/1p/command/
>> 
>> Signed-off-by: Olliver Schinagl <oliver at schinagl.nl>
>
> Applied, thanks.
>
> Ben.
>
>> ---
>>  klcc/Kbuild | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/klcc/Kbuild b/klcc/Kbuild
>> index eae753ff..0e625802 100644
>> --- a/klcc/Kbuild
>> +++ b/klcc/Kbuild
>> @@ -35,7 +35,7 @@ targets := $(KLIBCCROSS)klcc
>>  quiet_cmd_klcc = GEN     $@
>>        cmd_klcc = $(PERL) $< $(srctree)/$(src)/klcc.in \
>>                              $(obj)/$(KLIBCCROSS)klibc.config \
>> -                            $(shell bash -c 'type -p $(PERL)')
\
>> +                            $(shell command -v $(PERL)) \
>>  			      > $@ || ( rm -f $@ ; exit 1 ) && \
>>  			      chmod a+x $@
>>  $(obj)/$(KLIBCCROSS)klcc: $(src)/makeklcc.pl $(src)/klcc.in \
This doesn't work with older versions of make. ?make 4.2.1 seems common
now and does not support $(shell command).

$ cat Makefile
$(info take1: $(shell command -v ls))
$(info take2: $(shell bash -c 'type -p ls'))

all:
        @true

$ make-3.81/make
make: command: Command not found
take1:
take2: /bin/ls

$ make-4.2.1/make
make: command: Command not found
take1:
take2: /bin/ls

$ make-4.3/make
take1: /bin/ls
take2: /bin/ls

https://git.savannah.gnu.org/cgit/make.git/commit/?id=1af314465e5dfe3e8baa839a32a72e83c04f26ef
looks to be required and is in make 4.2.90+.

The kernel went with
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=913ab9780fc021298949cc5514d6255a008e69f9

So we might want:
  $(shell command -v $(PERL) 2> /dev/null)