From: Connor Kuehl <ckuehl@redhat.com>
To: Markus Armbruster <armbru@redhat.com>
Cc: kwolf@redhat.com, dillaman@redhat.com, qemu-devel@nongnu.org,
qemu-block@nongnu.org, mreitz@redhat.com
Subject: Re: General question about parsing an rbd filename
Date: Fri, 9 Apr 2021 12:06:50 -0500 [thread overview]
Message-ID: <41af7fc7-a9d5-a299-199e-ec789f7ad47c@redhat.com> (raw)
In-Reply-To: <87wntbfs7x.fsf@dusky.pond.sub.org>
On 4/9/21 9:27 AM, Markus Armbruster wrote:
> Connor Kuehl <ckuehl@redhat.com> writes:
>> block/rbd.c hints that:
>>
>>> * Configuration values containing :, @, or = can be escaped with a
>>> * leading "\".
>>
>> Right now, much of the parsing code will allow anyone to escape
>> _anything_ so long as it's preceded by '\'.
>>
>> Is this the intended behavior? Or should the parser be updated to
>> allow escaping only certain sequences.
>
> I can't answer this question, but perhaps I can get us a bit closer to
> an answer.
>
> The commend you quoted in part is about "rbd:" pseudo-filenames.
>
> By "parsing code", you probably mean qemu_rbd_parse_filename(). It uses
> qemu_rbd_next_tok() to split off one part after the other, stopping at a
> special delimiter character, and qemu_rbd_unescape() to unescape most,
> but not all parts.
>
> Both treat '\' followed by a character other than '\0' specially.
> qemu_rbd_next_tok() doesn't stop at an escaped delimiter character.
> qemu_rbd_unescape() unescapes escaped characters.
>
> I believe the comment you quoted is basically trying to say "to use a
> character that would normally be a delimiter, escape it with '\'". It
> doesn't say these are the only characters you may escape.
I agree with your interpretation here.
> Not unescaping some parts feels iffy to me.
I wonder if my reading of it placed too much emphasis on the
"Configuration values" part of it, which I understand to be the optional
key,value pairs that come after the image name.
Thank you,
Connor
prev parent reply other threads:[~2021-04-09 17:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 21:10 General question about parsing an rbd filename Connor Kuehl
2021-04-09 14:27 ` Markus Armbruster
2021-04-09 17:06 ` Connor Kuehl [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=41af7fc7-a9d5-a299-199e-ec789f7ad47c@redhat.com \
--to=ckuehl@redhat.com \
--cc=armbru@redhat.com \
--cc=dillaman@redhat.com \
--cc=kwolf@redhat.com \
--cc=mreitz@redhat.com \
--cc=qemu-block@nongnu.org \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).