From: erik quanstrom <quanstro@labs.coraid.com>
To: 9fans@9fans.net
Subject: Re: [9fans] stupid kernel question
Date: Fri, 1 Oct 2010 16:24:21 -0400 [thread overview]
Message-ID: <acbbbd521c91ac93a1c0f6fbb5eabc52@coraid.com> (raw)
In-Reply-To: <10bf630b13fbac21955790c6827f1ab4@quintile.net>
On Fri Oct 1 15:25:16 EDT 2010, steve@quintile.net wrote:
> how does kernel code call plan9 system calls, does it perform a
> trap from kernel back into kernel space and make the request just
> like a user process or is there a more direct, subtle route?
the short answer is that it doesn't. but read/write/open/close/stat
are done via channels, and often with Blocks. for example
(hopefully without typos)
c = namec("/sys/src/9/pc/mkfile", Aopen, OREAD, 0); /* can call error */
b = devtab[c->type]->bread(c, 64*1024, 0);
/* b->wp points to data if successful BLEN(b) is the length */
- erik
next prev parent reply other threads:[~2010-10-01 20:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-01 19:17 Steve Simon
2010-10-01 20:24 ` erik quanstrom [this message]
2010-10-01 20:25 ` Francisco J Ballesteros
2010-10-01 22:03 ` Steve Simon
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=acbbbd521c91ac93a1c0f6fbb5eabc52@coraid.com \
--to=quanstro@labs.coraid.com \
--cc=9fans@9fans.net \
/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).