[BusyBox] Adding an option to tar

R. Weber rjweber at onz.com
Sat Oct 16 23:06:23 UTC 2004


Thanks Glen. This worked fine. The m option isn't displayed as an option, 
which I may add, but functionally, it works. Excellent.

- Bob

On Thursday 14 October 2004 6:16 pm, Glenn McGrath wrote:
> On Thu, 14 Oct 2004 16:45:21 -0700
>
> "R. Weber" <rjweber at onz.com> wrote:
> > Hello. I'm using busybox on a box that must integrate to an existing
> > system. This system downloads files via ftp, and then untars them. The
> > untar options are xzmf "filename". "m" is used to get rid of
> > complaints about differing time stamps.
> >
> > Busybox tar doesn't support the m option. I could add tar separately,
> > but tar is huge, at least by default. I'd like to add this option to
> > busybox. Looking at the tar.c code, I'm lost as to how to go about
> > this. I've added the line
> >
> >  { "no-file-time",  0, NULL, 'm' },
> >
> > to the tar_long_options structure, which I thought would allow the m
> > option, even though I haven't added any code for it yet, but the m
> > option is still unrecognized. Is there a write-up somewhere that might
> > bet me up to speed on changes to busybox, a design guideline, or
> > something?
>
> The tar_long_options arent always used.
>
> The short options are somewhat complex in tar, but its required to add
> add all the different options into bb_getopt_ulflags() which is what
> does all the work sorting out the options.
>
> The main documents we have regarding adding options are comments in the
> code, many people find bb_getopt_ulflags hard to understand, its best to
> learn it by looking at existing applets that use it.
>
> Attached is a patch which adds the tar -m option, which you should be
> able to follow to see how it works.
>
> Although busybox has released 1.0, we are still in a feature freese, so
> i wont commit this patch yet.
>
> Busybox's 1.0 series will be just for bugfixes and a new "development"
> branch will be added for new features. We need to move to subversion
> before that happens. (it was mentioned on irc yesterday)
>
>
> Glenn



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