Re: [PATCH 2/5] raisin: Detect systemd

[George Dunlap <george.dunlap@citrix.com>]

On 16/10/15 15:04, Stefano Stabellini wrote:
> On Fri, 16 Oct 2015, Ian Campbell wrote:
>> On Fri, 2015-10-16 at 14:39 +0100, Stefano Stabellini wrote:
>>> On Wed, 14 Oct 2015, George Dunlap wrote:
>>>> Add systemd development libraries if we detect systemd present on the
>>>> system
>>>>
>>>> Signed-off-by: George Dunlap <george.dunlap@citrix.com>
>>>
>>> Please use spaces for indentation
>>>
>>>     
>>>>  components/xen | 10 ++++++++++
>>>>  1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/components/xen b/components/xen
>>>> index 090cceb..93ed288 100644
>>>> --- a/components/xen
>>>> +++ b/components/xen
>>>> @@ -8,6 +8,11 @@ function xen_check_package() {
>>>>      local DEP_Debian_common="build-essential python-dev gettext uuid
>>>> -dev   \
>>>>               libncurses5-dev libyajl-dev libaio-dev pkg-config
>>>> libglib2.0-dev  \
>>>>               libssl-dev libpixman-1-dev bridge-utils wget"
>>>> +
>>>> +    if [[ -e "/usr/lib/systemd" ]]
>>>
>>> I don't know much about systemd but isn't there a better way to detect
>>> systemd? Check if it is running for example?
>>
>> You might want to build with systemd support even if systemd isn't actually
>> the current init system the system was booted with?
> 
> That is possible but also the vice versa might be true: one might want
> to build without systemd even if systemd is running. Maybe we need some
> kind of variable that can be overridden by the user?

You mean like XEN_CONFIG_EXTRA? :-D

For people frobbing around with XEN_CONFIG_EXTRA, I think it's
reasonable for them to get a build error if they add --with-systemd but
don't have the requisite packages.  (I'm pretty sure that's what will
happen now, at any rate.)

Since I'm going to be checking for systemd packages anyway due to the
container issue, maybe it would just make sense to include the dep
automatically only if the systemd packages are installed.

Alternately, I suppose we could extend the check-package "syntax" to
have "if package X in stalled, add dependency Y" -- similar to the '|'
operator we added earlier.  Then we could do something like this:

systemd:systemd-devel systemd-container:systemd-container-devel

What do you think?

 -George