[PATCH libmnl] build: doc: refer to bash as bash, not /bin/bash

[PATCH libmnl] build: doc: refer to bash as bash, not /bin/bash

[Mark Mentovai]

This locates bash according to its presence in the PATH, not at a
hard-coded path which may not exist or may not be the most suitable bash
to use.

Signed-off-by: Mark Mentovai <mark@mentovai.com>
---
 doxygen/Makefile.am | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doxygen/Makefile.am b/doxygen/Makefile.am
index 29078dee122a..189a233f3760 100644
--- a/doxygen/Makefile.am
+++ b/doxygen/Makefile.am
@@ -21,7 +21,7 @@ doxyfile.stamp: $(doc_srcs) Makefile.am
 # The command has to be a single line so the functions work
 # and so `make` gives all lines to `bash -c`
 # (hence ";\" at the end of every line but the last).
-	/bin/bash -p -c 'declare -A renamed_page;\
+	bash -p -c 'declare -A renamed_page;\
 main(){ set -e; cd man/man3; rm -f _*;\
   count_real_pages;\
   rename_real_pages;\
-- 
2.37.1

Re: [PATCH libmnl] build: doc: refer to bash as bash, not /bin/bash

[Duncan Roe]

Hi Mark,

On Mon, Aug 01, 2022 at 01:26:20PM -0400, Mark Mentovai wrote:
> This locates bash according to its presence in the PATH, not at a
> hard-coded path which may not exist or may not be the most suitable bash
> to use.
>
> Signed-off-by: Mark Mentovai <mark@mentovai.com>
> ---
>  doxygen/Makefile.am | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/doxygen/Makefile.am b/doxygen/Makefile.am
> index 29078dee122a..189a233f3760 100644
> --- a/doxygen/Makefile.am
> +++ b/doxygen/Makefile.am
> @@ -21,7 +21,7 @@ doxyfile.stamp: $(doc_srcs) Makefile.am
>  # The command has to be a single line so the functions work
>  # and so `make` gives all lines to `bash -c`
>  # (hence ";\" at the end of every line but the last).
> -	/bin/bash -p -c 'declare -A renamed_page;\
> +	bash -p -c 'declare -A renamed_page;\
>  main(){ set -e; cd man/man3; rm -f _*;\
>    count_real_pages;\
>    rename_real_pages;\
> --
> 2.37.1
>
I would not apply this patch unless it's actually necessary for some
distribution.

If you have discovered a distribution where /bin/bash doesn't work, please let
us know.

Scripts that start "#!/bin/bash" are not uncommon, and Netfilter already has a
couple of these, in libnetfilter_queue and libnetfilter_log.

I somehow omitted to update libmnl to replace the cumbersome embedded script in
Makefile.am with a stand-alone script, but you've reminded me.

Cheers ... Duncan.

Re: [PATCH libmnl] build: doc: refer to bash as bash, not /bin/bash

[Mark Mentovai]

Duncan Roe wrote:
> On Mon, Aug 01, 2022 at 01:26:20PM -0400, Mark Mentovai wrote:
>> This locates bash according to its presence in the PATH, not at a
>> hard-coded path which may not exist or may not be the most suitable bash
>> to use.
>>
>> Signed-off-by: Mark Mentovai <mark@mentovai.com>
>> ---
>>  doxygen/Makefile.am | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/doxygen/Makefile.am b/doxygen/Makefile.am
>> index 29078dee122a..189a233f3760 100644
>> --- a/doxygen/Makefile.am
>> +++ b/doxygen/Makefile.am
>> @@ -21,7 +21,7 @@ doxyfile.stamp: $(doc_srcs) Makefile.am
>>  # The command has to be a single line so the functions work
>>  # and so `make` gives all lines to `bash -c`
>>  # (hence ";\" at the end of every line but the last).
>> -	/bin/bash -p -c 'declare -A renamed_page;\
>> +	bash -p -c 'declare -A renamed_page;\
>>  main(){ set -e; cd man/man3; rm -f _*;\
>>    count_real_pages;\
>>    rename_real_pages;\
>> --
>> 2.37.1
>>
> I would not apply this patch unless it's actually necessary for some
> distribution.
>
> If you have discovered a distribution where /bin/bash doesn't work, please let
> us know.
>
> Scripts that start "#!/bin/bash" are not uncommon, and Netfilter already has a
> couple of these, in libnetfilter_queue and libnetfilter_log.
>
> I somehow omitted to update libmnl to replace the cumbersome embedded script in
> Makefile.am with a stand-alone script, but you've reminded me.
>
> Cheers ... Duncan.

The context here is in OpenWrt, 
https://github.com/openwrt/openwrt/commit/beeb49740bb4. The use of 
/bin/bash is a problem during a cross build of libmnl, with a build system 
running macOS or BSD. /bin/bash on macOS is an unsuitably old version, and 
the OpenWrt build ensures that a recent bash is available in PATH. BSD 
derivatives tend not to have /bin/bash at all, although bash may be 
present elsewhere in PATH. Again, the OpenWrt build ensures this.

I would not expect the same treatment to be strictly necessary for scripts 
like libnetfilter_queue or libnetfilter_log, which run on the target 
system, but the reliance on /bin/bash is a problem for cross builds and in 
particular non-Linux build systems. Considering that these cross builds 
are otherwise perfectly clean given an appropriate toolchain, it seems 
unnecessary to leave them broken for something like this, when a simple 
reliance on locating bash via PATH ought to suffice for everyone.

Mark

Re: [PATCH libmnl] build: doc: refer to bash as bash, not /bin/bash

[Duncan Roe]

On Tue, Aug 02, 2022 at 02:14:29PM -0400, Mark Mentovai wrote:
[...]
>
> The context here is in OpenWrt,
> https://github.com/openwrt/openwrt/commit/beeb49740bb4. The use of /bin/bash
> is a problem during a cross build of libmnl, with a build system running
> macOS or BSD. /bin/bash on macOS is an unsuitably old version, and the
> OpenWrt build ensures that a recent bash is available in PATH. BSD
> derivatives tend not to have /bin/bash at all, although bash may be present
> elsewhere in PATH. Again, the OpenWrt build ensures this.
>
> I would not expect the same treatment to be strictly necessary for scripts
> like libnetfilter_queue or libnetfilter_log, which run on the target system,
> but the reliance on /bin/bash is a problem for cross builds and in
> particular non-Linux build systems. Considering that these cross builds are
> otherwise perfectly clean given an appropriate toolchain, it seems
> unnecessary to leave them broken for something like this, when a simple
> reliance on locating bash via PATH ought to suffice for everyone.
>
> Mark

Good enough for me - I acked the original patch.

Cheers ... Duncan.

Re: [PATCH libmnl] build: doc: refer to bash as bash, not /bin/bash

[Duncan Roe]

On Mon, Aug 01, 2022 at 01:26:20PM -0400, Mark Mentovai wrote:
> This locates bash according to its presence in the PATH, not at a
> hard-coded path which may not exist or may not be the most suitable bash
> to use.
>
> Signed-off-by: Mark Mentovai <mark@mentovai.com>
> ---
>  doxygen/Makefile.am | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/doxygen/Makefile.am b/doxygen/Makefile.am
> index 29078dee122a..189a233f3760 100644
> --- a/doxygen/Makefile.am
> +++ b/doxygen/Makefile.am
> @@ -21,7 +21,7 @@ doxyfile.stamp: $(doc_srcs) Makefile.am
>  # The command has to be a single line so the functions work
>  # and so `make` gives all lines to `bash -c`
>  # (hence ";\" at the end of every line but the last).
> -	/bin/bash -p -c 'declare -A renamed_page;\
> +	bash -p -c 'declare -A renamed_page;\
>  main(){ set -e; cd man/man3; rm -f _*;\
>    count_real_pages;\
>    rename_real_pages;\
> --
> 2.37.1
>
Acked-by: Duncan Roe <duncan_roe@optusnet.com.au>