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To: Warner Losh <imp@bsdimp.com>
cc: "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org>
Subject: Re: mtree "language" enhancements
In-reply-to: <CANCZdfrDtfkwKxMV3o9tcQNzBQDKZdTx1JErkTKtC7UZORT5aA@mail.gmail.com>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
References: <CANCZdfrDtfkwKxMV3o9tcQNzBQDKZdTx1JErkTKtC7UZORT5aA@mail.gmail.com>
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Date: Sun, 29 Nov 2015 18:16:07 +0000
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--------
In message <CANCZdfrDtfkwKxMV3o9tcQNzBQDKZdTx1JErkTKtC7UZORT5aA@mail.gmail=
.com>
, Warner Losh writes:

>As part of making NanoBSD buildable by non-root, I've found a need to hav=
e
>a richer mtree language than we currently have.

>I'd like a new type called 'action' (so type=3Daction in the records). Th=
is
>type is defined loosely to manipulate and earlier entry (or maybe entries=
,
>still unsure) in the file.

I suggest you define this so that all records have an action, and that
the default action is "create"

>2. "move" which relocates a previous entry. An additional targetpath
>keyword specifies the ultimate destination for this entry.
>3. "copy" which duplicates a previous entry. It too takes targetpath.

Is targetpath absolute or relative ?

Can it reach out of the mtree root ?

>4. "meta" which changes the meta data of the previous entry. All keywords
>on this are merged with the previous entry.

System-III called this "chmog" if I recall correctly :-)

>The one other thing that my merging tool does is to remove all size
>keywords.

That sounds wrong to me.  Shouldn't you just emit "meta" records updating
the size as appropriate ?

What about digest fields ?

-- =

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    =

Never attribute to malice what can adequately be explained by incompetence=
.