GNU bug report logs - #55093
"split -n K/N <file>" BUG: Last Chunk incomplete if input file >= 262144 bytes

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Adam Holt <holt <at> unleashkids.org>
To: bug-coreutils <at> gnu.org, Torbjörn Granlund <tg <at> gmplib.org>, 
 Richard Stallman <rms <at> gnu.org>
Subject: "split -n K/N <file>" BUG: Last Chunk incomplete if input file >=
 262144 bytes
Date: Sun, 24 Apr 2022 10:40:01 -0400

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Hello !

Where do I report a serious data loss bug with GNU's split command?

Example:

$ dd if=/dev/random of=file bs=262144 count=1    # Create file containing
262144 bytes

$ split -n 1/2 file | wc -c
131072
$ split -n 2/2 file | wc -c
0    # SHOULD BE 131072

split -n 1/3 file | wc -c
87381
split -n 2/3 file | wc -c
87381
split -n 3/3 file | wc -c
0    # SHOULD BE 87382


The Last Chunk is completely missing, as you can see in both above examples.

Additionally, if the input file is larger than 2^18 = 262144 bytes, the
Last Chunk generated by "split -n K/N file" is then truncated (i.e. many
bytes are missing, from the beginning of the Last Chunk).

Here's the version number I'm running:

$ split --version
split (GNU coreutils) 8.32
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <
https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Torbjorn Granlund and Richard M. Stallman.


Thanks so much for your help forwarding this to anybody who might be able
to confirm and ideally resolve this for all !

Regards,
Adam

--
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Message #8 received at 55093 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Adam Holt <holt <at> unleashkids.org>
Cc: 55093 <at> debbugs.gnu.org
Subject: Re: bug#55093: "split -n K/N <file>" BUG: Last Chunk incomplete if
 input file >= 262144 bytes
Date: Sun, 24 Apr 2022 16:14:24 -0700

On 4/24/22 07:40, Adam Holt wrote:

> split (GNU coreutils) 8.32

That's an old version, dated 2020. Please try the current version 
coreutils 9.1, which has bug fixes in this area.

Also, there's no need to cc. rms and tg; they're not working on 'split' 
any more.

Thanks.

Message #13 received at 55093 <at> debbugs.gnu.org (full text, mbox):

From: Adam Holt <holt <at> unleashkids.org>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 55093 <at> debbugs.gnu.org
Subject: Re: bug#55093: "split -n K/N <file>" BUG: Last Chunk incomplete if
 input file >= 262144 bytes
Date: Sun, 24 Apr 2022 19:59:11 -0400

[Message part 1 (text/plain, inline)]

On Sun, Apr 24, 2022 at 7:14 PM Paul Eggert <eggert <at> cs.ucla.edu> wrote:

> On 4/24/22 07:40, Adam Holt wrote:
>
> > split (GNU coreutils) 8.32
>
> That's an old version, dated 2020. Please try the current version
> coreutils 9.1, which has bug fixes in this area.


Wow, coreutils 9.1 indeed fixes this data loss issue with "split -n K/N",
Thanks Paul!

--
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