From: Rich Felker <dalias@aerifal.cx>
To: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: libc-alpha <libc-alpha@sourceware.org>, musl@lists.openwall.com
Subject: Re: O_EXEC and O_SEARCH
Date: Sat, 23 Feb 2013 00:05:42 -0500 [thread overview]
Message-ID: <20130223050542.GX20323@brightrain.aerifal.cx> (raw)
In-Reply-To: <CAHGf_=oa5gW_1511i6Wi4nTHHdiUaeLXucT+mr-76MFVqRm7rw@mail.gmail.com>
On Sat, Feb 23, 2013 at 12:01:39AM -0500, KOSAKI Motohiro wrote:
> > 1. Try to open with O_RDONLY. If it succeeds, we're done. This is
> > REALLY nice because it means O_SEARCH and O_EXEC "just work" even on
> > ancient or broken kernels as long as the target file is readable.
>
> Hmm..
> This algorithm seems slightly strange to me. Why do you want to try O_RDONLY at
> first?
> O_RDONLY require read permission and O_SEARCH, if i understand correctly,
> doesn't.
> I think you should try O_PATH at first.
If the file is readable, O_RDONLY will succeed and provides the
necessary semantics for O_EXEC and O_SEARCH. The only time O_EXEC or
O_SEARCH needs special support is when the file is not readable; these
modes were specifically designed for supporting that case.
Rich
next prev parent reply other threads:[~2013-02-23 5:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-22 0:45 Rich Felker
2013-02-23 3:05 ` KOSAKI Motohiro
2013-02-23 3:17 ` Rich Felker
2013-02-23 3:58 ` KOSAKI Motohiro
2013-02-23 4:33 ` Rich Felker
2013-02-23 5:01 ` KOSAKI Motohiro
2013-02-23 5:05 ` Rich Felker [this message]
2013-02-23 5:21 ` KOSAKI Motohiro
2013-02-23 4:54 ` KOSAKI Motohiro
2013-02-23 5:03 ` Rich Felker
2013-02-23 5:20 ` KOSAKI Motohiro
2013-02-23 5:28 ` KOSAKI Motohiro
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=20130223050542.GX20323@brightrain.aerifal.cx \
--to=dalias@aerifal.cx \
--cc=kosaki.motohiro@gmail.com \
--cc=libc-alpha@sourceware.org \
--cc=musl@lists.openwall.com \
/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.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/musl/
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).