From: Steven Vormwald <sdvormwa@mtu.edu>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] _tos puzzle
Date: Thu, 8 May 2008 13:40:42 -0400 [thread overview]
Message-ID: <1210268442.11438.3.camel@wren> (raw)
In-Reply-To: <20080508172816.4B2D71E8C55@holo.morphisms.net>
On Thu, 2008-05-08 at 13:24 -0400, Russ Cox wrote:
> > So I have to allocate 56 bytes (sizeof(Tos) on 386) of space above the
> > top of stack (before copying argc and argv) and set AX to that
> > address, correct?
>
> Yes. And you need to maintain it.
> At the very least you need to initialize tos->pid
> and update it on return from rfork.
>
> > The clone(2) system call in linux allows for creation of child
> > processes that share address space with its parent, with the exception
> > of the stack segment.
>
> It does? I don't see that anywhere in the man page.
>
> Russ
Wouldn't the CLONE_VM flag do this?
CLONE_VM
If CLONE_VM is set, the calling process and the child processes
run in the same memory space. In particular, memory writes per‐
formed by the calling process or by the child process are also
visible in the other process. Moreover, any memory mapping or
unmapping performed with mmap(2) or munmap(2) by the child or
calling process also affects the other process.
Steven Vormwald
next prev parent reply other threads:[~2008-05-08 17:40 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-08 16:18 Anant Narayanan
2008-05-08 16:41 ` Russ Cox
2008-05-08 17:13 ` Anant Narayanan
2008-05-08 17:24 ` Russ Cox
2008-05-08 17:40 ` Steven Vormwald [this message]
2008-05-08 19:19 ` Anant Narayanan
2008-05-08 20:33 ` Russ Cox
2008-05-09 5:30 ` Anant Narayanan
2008-05-09 13:08 ` Russ Cox
2008-05-08 17:50 ` Charles Forsyth
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=1210268442.11438.3.camel@wren \
--to=sdvormwa@mtu.edu \
--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).