[OE-core] [PATCH] busybox: Add a dependency on virtual/crypt

[Andre McCurdy]

On Mon, Aug 20, 2018 at 12:45 PM, Khem Raj <raj.khem at gmail.com> wrote:
> On Mon, Aug 20, 2018 at 2:45 AM Richard Purdie
> <richard.purdie at linuxfoundation.org> wrote:
>>
>> On Mon, 2018-08-20 at 04:46 +0200, Peter Kjellerstedt wrote:
>> > busybox needs crypt() if CONFIG_USE_BB_CRYPT is not defined.
>> >
>> > Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt at axis.com>
>> > ---
>> >  meta/recipes-core/busybox/busybox.inc | 3 ++-
>> >  1 file changed, 2 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/meta/recipes-core/busybox/busybox.inc b/meta/recipes-
>> > core/busybox/busybox.inc
>> > index 8c6dbbaf9b..a8ba10d21c 100644
>> > --- a/meta/recipes-core/busybox/busybox.inc
>> > +++ b/meta/recipes-core/busybox/busybox.inc
>> > @@ -3,7 +3,8 @@ DESCRIPTION = "BusyBox combines tiny versions of many
>> > common UNIX utilities into
>> >  HOMEPAGE = "http://www.busybox.net"
>> >  BUGTRACKER = "https://bugs.busybox.net/"
>> >
>> > -DEPENDS += "kern-tools-native"
>> > +# Depend on virtual/crypt in case CONFIG_USE_BB_CRYPT is not defined
>> > +DEPENDS += "kern-tools-native virtual/crypt"
>>
>> I'm not a bug fan of adding dependencies which might not be needed. How
>> common is CONFIG_USE_BB_CRYPT not being defined? I assume that isn't
>> our default config?
>
> yes perhaps it should be packageconfig

Busybox doesn't use PACKAGECONFIG. Conditional configuration is
handled by adding / removing cfg fragments and testing whether SRC_URI
contains "foo.cfg" (and also parsing the final .config within tasks
such as do_install). Unfortunately that approach doesn't work so well
for conditional build dependencies...

Our Busybox defconfig does enable CONFIG_USE_BB_CRYPT (and there's no
cfg fragment to disable it) so the virtual/crypt dependency isn't
needed in our default builds.

Disabling busybox's internal crypt functions doesn't seem like a very
common thing to want to do.

config USE_BB_CRYPT
    bool "Use internal crypt functions"
    default y
    help
      Busybox has internal DES and MD5 crypt functions.
      They produce results which are identical to corresponding
      standard C library functions.

      If you leave this disabled, busybox will use the system's
      crypt functions. Most C libraries use large (~70k)
      static buffers there, and also combine them with more general
      DES encryption/decryption.

      For busybox, having large static buffers is undesirable,
      especially on NOMMU machines. Busybox also doesn't need
      DES encryption/decryption and can do with smaller code.

      If you enable this option, it will add about 4.8k of code
      if you are building dynamically linked executable.
      In static build, it makes code _smaller_ by about 1.2k,
      and likely many kilobytes less of bss.