[Buildroot] [PATCH] [RFC] system: add option to choose what /bin/sh points to

[Arnout Vandecappelle]

On 12/10/14 11:57, Peter Korsgaard wrote:
>>>>>> "Yann" == Yann E MORIN <yann.morin.1998 at free.fr> writes:
> 
>  > Not all our shells do install a pointer to /bin/sh. Besides, between
>  > those that do and multiple ones are enabled, the last one to install
>  > wins the the symlink.
> 
>  > Add a new config choice in the system sub-menu that allows the user to
>  > explicitly select the shell to provide /bin/sh.
> 
>  > Remove the symlink creation from bash.mk at the same time.
> 
>  > Note: for every shell, we select them, except busybox, on which we
>  > depend, on the assumption that we do not want to force busybox in case
>  > the user decided not to enable it.
> 
> But we default to BR2_INIT_BUSYBOX, so you still need to go into the
> system menu and disable that before you can deselect busybox.
> 
> Another issue with the 'depends on' is that if you disable busybox the
> choice then jumps to the next option which pulls in bash (which might
> not really be what you want when you try to save space by disabling
> busybox).
> 
> So I think it is better to use selects everywhere.

 I disagree.

 For people who want to avoid busybox, it is already annoying that they have to
change their init system first. Adding more implicit selects of busybox is not
going to make their life easier.

 For the jumping, it's better to fix it by adding a 'default dash if !busybox' line.

 And since busybox is on by default, there is no strong need for a select - if
the user deselects busybox I guess they know what they're doing.

 And also using a depends solves the issue you mention below :-)


 Regards,
 Arnout

> 
>  > Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
>  > Cc: Gustavo Zacarias <gustavo at zacarias.com.ar>
>  > ---
>  >  package/bash/bash.mk |  1 -
>  >  system/Config.in     | 43 +++++++++++++++++++++++++++++++++++++++++++
>  >  system/system.mk     | 12 ++++++++++++
>  >  3 files changed, 55 insertions(+), 1 deletion(-)
> 
>  > diff --git a/package/bash/bash.mk b/package/bash/bash.mk
>  > index 6510af5..34a3a73 100644
>  > --- a/package/bash/bash.mk
>  > +++ b/package/bash/bash.mk
>  > @@ -35,7 +35,6 @@ define BASH_INSTALL_TARGET_CMDS
>  >  	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) \
>  >  		DESTDIR=$(TARGET_DIR) exec_prefix=/ install
>  >  	rm -f $(TARGET_DIR)/bin/bashbug
>  > -	ln -sf bash $(TARGET_DIR)/bin/sh
>  >  endef
>  
>  >  $(eval $(autotools-package))
>  > diff --git a/system/Config.in b/system/Config.in
>  > index e7e146a..22f37ea 100644
>  > --- a/system/Config.in
>  > +++ b/system/Config.in
>  > @@ -211,6 +211,49 @@ config BR2_TARGET_GENERIC_ROOT_PASSWD
>  >  	  in the build log! Avoid using a valuable password if either the
>  >  	  .config file or the build log may be distributed!
>  
>  > +choice
>  > +	bool "/bin/sh"
>  > +	help
>  > +	  Select which shell will provide /bin/sh.
>  > +
>  > +# busybox has shells that work on noMMU
>  > +config BR2_SYSTEM_BIN_SH_BUSYBOX
>  > +	bool "busybox' default shell"
>  > +	depends on BR2_PACKAGE_BUSYBOX
>  > +
>  > +config BR2_SYSTEM_BIN_SH_BASH
>  > +	bool "bash"
>  > +	depends on BR2_USE_MMU # bash
>  > +	depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS || !BR2_PACKAGE_BUSYBOX
> 
> You arguably don't need the || !BR2_PACKAGE_BUSYBOX as we do a trick and
> make BR2_PACKAGE_BUSYBOX_SHOW_OTHERS a hidden symbol (=y) when busybox
> isn't enabled.
> 
> With that said, it doesn't actually work when I change the busybox
> option to use select:
> 
> system/Config.in:214:error: recursive dependency detected!
> system/Config.in:214:   choice <choice> contains symbol BR2_SYSTEM_BIN_SH_BASH
> system/Config.in:224:   symbol BR2_SYSTEM_BIN_SH_BASH depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS
> package/busybox/Config.in:23:   symbol BR2_PACKAGE_BUSYBOX_SHOW_OTHERS depends on BR2_PACKAGE_BUSYBOX
> package/busybox/Config.in:1:    symbol BR2_PACKAGE_BUSYBOX is selected by BR2_SYSTEM_BIN_SH_BUSYBOX
> system/Config.in:220:   symbol BR2_SYSTEM_BIN_SH_BUSYBOX is part of choice <choice>
> 
> Any idea what we can do?
> 


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
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