From: Joe Perches <joe@perches.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
Julia Lawall <julia.lawall@lip6.fr>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
LKML <linux-kernel@vger.kernel.org>,
clang-built-linux@googlegroups.com,
Linux Next Mailing List <linux-next@vger.kernel.org>
Subject: Re: rfc: treewide scripted patch mechanism? (was: Re: [PATCH] Makefile: Convert -Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang)QUILT
Date: Tue, 20 Aug 2019 16:37:27 -0700 [thread overview]
Message-ID: <9d12995c5e7e41fc5d8ba202f76a2cf854183245.camel@perches.com> (raw)
In-Reply-To: <CAHk-=wgqQKoAnhmhGE-2PBFt7oQs9LLAATKbYa573UO=DPBE0Q@mail.gmail.com>
On Tue, 2019-08-20 at 16:28 -0700, Linus Torvalds wrote:
> On Mon, Aug 19, 2019 at 5:08 PM Joe Perches <joe@perches.com> wrote:
> > 2: would be Julia Lawall's stracpy change done
> > with coccinelle: (attached)
>
> I'm not actually convinced about stracpy() and friends.
>
> It seems to be yet another badly thought out string interface, and
> there are now so many of them that no human being can keep track of
> them.
>
> The "badly thought out" part is that it (like the original strlcpy
> garbage from BSD) thinks that there is only one size that matters -
> the destination.
>
> Yes, we fixed part of the "source is also limited" with strscpy(). It
> didn't fix the problem with different size limits, but at least it
> fixed the fundamentally broken assumption that the source has no size
> limit at all.
>
> Honestly, I really really REALLY don't want yet another broken string
> handling function, when we still have a lot of the old strlcpy() stuff
> in the tree from previous broken garbage.
>
> The fact is, when you copy strings, both the destination *AND* the
> source may have size limits. They may be the same. Or they may not be.
>
> This is particularly noticeable in the "str*_pad()" versions. It's
> simply absolutely and purely wrong. I will note that we currently have
> not a single user or strscpy_pad() in the whole kernel outside of the
> testing code.
>
> And yes, we actually *do* have real and present cases of "source and
> destination have different sizes". They aren't common, but they do
> exist.
>
> So I'm putting my foot down on yet another broken string copy
> interface from people who do not understand this fundamental issue.
I think you are mistaken about the stracpy limits as
the only limit is not the source size but the dest.
Why should the source be size limited?
btw: I also think str.cpy_pad is horrible.
next prev parent reply other threads:[~2019-08-20 23:37 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-05 22:11 [PATCH] Makefile: Convert -Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang Joe Perches
2019-08-05 22:23 ` Nathan Chancellor
2019-08-10 19:32 ` Joe Perches
2019-08-10 19:44 ` Linus Torvalds
2019-08-10 20:18 ` Joe Perches
2019-08-10 20:33 ` Joe Perches
2019-08-16 19:58 ` rfc: treewide scripted patch mechanism? (was: Re: [PATCH] Makefile: Convert -Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang) Joe Perches
2019-08-19 23:24 ` rfc: treewide scripted patch mechanism? (was: Re: [PATCH] Makefile: Convert -Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang)QUILT Stephen Rothwell
2019-08-20 0:08 ` Joe Perches
2019-08-20 23:28 ` Linus Torvalds
2019-08-20 23:37 ` Joe Perches [this message]
2019-08-21 0:39 ` Linus Torvalds
2019-08-26 8:58 ` Geert Uytterhoeven
2019-08-21 0:20 ` Joe Perches
2019-08-21 0:43 ` Linus Torvalds
2019-08-21 0:58 ` stracpy Joe Perches
2019-08-21 4:01 ` rfc: treewide scripted patch mechanism? (was: Re: [PATCH] Makefile: Convert -Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang)QUILT Willy Tarreau
2019-08-21 0:33 ` Stephen Rothwell
2019-08-11 2:04 ` [PATCH] Makefile: Convert -Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang Nathan Chancellor
2019-08-11 3:06 ` Joe Perches
2019-08-11 3:17 ` Nathan Chancellor
2019-08-11 3:54 ` Joe Perches
2019-08-12 5:07 ` Joe Perches
2019-08-11 6:50 ` Bernd Petrovitsch
2019-08-12 16:28 ` Nick Desaulniers
2019-08-12 17:42 ` Joe Perches
2019-08-13 12:44 ` Miguel Ojeda
2019-08-15 2:44 ` Joe Perches
2019-08-16 8:47 ` Joe Perches
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=9d12995c5e7e41fc5d8ba202f76a2cf854183245.camel@perches.com \
--to=joe@perches.com \
--cc=clang-built-linux@googlegroups.com \
--cc=gustavo@embeddedor.com \
--cc=julia.lawall@lip6.fr \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-next@vger.kernel.org \
--cc=sfr@canb.auug.org.au \
--cc=torvalds@linux-foundation.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).