Date: Tue, 7 Nov 2000 15:21:35 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Jeroen Ruigrok van der Werven <jruigrok@via-net-works.nl> Cc: "John W. De Boskey" <jwd@FreeBSD.ORG>, Current List <freebsd-current@FreeBSD.ORG> Subject: Re: tar : needs some attention? Message-ID: <Pine.BSF.4.21.0011071453100.2492-100000@besplex.bde.org> In-Reply-To: <20001106180013.W43259@lucifer.bart.nl>
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On Mon, 6 Nov 2000, Jeroen Ruigrok van der Werven wrote:
> -On [20001106 17:10], John W. De Boskey (jwd@FreeBSD.ORG) wrote:
> >tar: cdrom/disc2/dev/acd0t39: minor number too large; not dumped
> >
> > Is this the expected behaviour, or is it worth digging into
> >tar and making some fixes?
>
> I am hoping to update tar soon these weeks.
Don't forget to merge all the FreeBSD changes including the ones that
print this message. For the file:
crw-rw---- 1 root operator 9, 0x08010002 Feb 12 1995 fd0.1200
gnu tar (v.1.13) prints the user-unfriendly message:
tar: minor_t value 134283266 too large (max=16777215)
while FreeBSD tar prints:
tar: fd0.1200: minor number too large; not dumped
It is not easy to see that 134283266 is 0x08010002 or that the file is
fd0.1200 (the limit 16777215 is 0xFFFFFF -- 24 bits).
gnu tar 1.13 actually dumps acd0t39, and FreeBSD tar reads back the
result correctly. This is because gnu tar 1.13 permits 24-bit minor
numbers, while the FreeBSD version only permits 21-bit ones since it
requires a byte of null padding in the minor number field. I seem to
have misread the gnu tar 1.13 sources in the following commit:
RCS file: /home/ncvs/src/gnu/usr.bin/tar/create.c,v
Working file: create.c
head: 1.7
...
----------------------------
revision 1.7
date: 1999/08/11 08:03:39; author: bde; state: Exp; lines: +15 -2
Support 21-bit minor numbers. Avoid wasting a byte in their octal
representation by generating the same format as tar-1.13 (use a single
space as the terminator for 7-digit octal numbers). This is POSIX.1
conformant (2-byte terminators are just a bug or historical wart in
old versions of gnu tar). All devices created by `MAKEDEV all' except
rsa0.ctl can now be handled by tar(1).
----------------------------
Previous versions of FreeBSD wasted 2 bytes for null padding. The
current version still wastes (?) 1 byte relative to gnu tar 1.13.
Bruce
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