Interworking of cron and sendmail applets

[Denys Vlasenko]

On Wed, Jan 22, 2014 at 5:37 PM, Kaarle Ritvanen
<kaarle.ritvanen at datakunkku.fi> wrote:
> On Tue, 21 Jan 2014, Harald Becker wrote:
>> Beside modifying the Busybox binary, you can create a script file
>> for sendmail:
>>
>> #!/bin/sh
>> exec /bin/busybox sendmail -f ... "$@"
>>
>> install this script as your sendmail and make it executable
>> (chmod +x). Then cron shall pickup this script for sendmail and
>> the script will add the missing information.
>
> Of course, there are ways to hack around the problem, but I prefer a
> solution that's easy to replicate in multiple environments with minimum
> hassle.
>
> I would like to understand why the sendmail applet requires the use of the
> -f option. It used to be optional, but it was made mandatory in commit
> 88b8f0a, which has an informative commit log message: "sendmail: update by
> Vladimir".

Vladimir is the author of those applets. I diecided that he knows
what he is doing.

> I suggest the -f option be made optional again unless there are
> good reasons not to do so.

The goal here is for applet to not deviate from the behavior
of "standard" version of the tool, if it is possible without
large code increase.

I am looking at Fedora's "man sendmail" and it says that -fSENDER
is optional. When it's absent, sender is derived from "From:" header.

IOW: a patch to make it so for busybox sendmail is ok.