From: cinap_lenrek@gmx.de
To: 9fans@9fans.net
Subject: Re: [9fans] exec() question
Date: Fri, 15 Mar 2013 21:35:49 +0100 [thread overview]
Message-ID: <6c7727bd06577062ffdbadcef28e33bf@rei2.9hal> (raw)
In-Reply-To: <aab086c1caa3c5fbe10219ef85ca601f@ladd.quanstro.net>
i think you are right. the temporary tstk segment will be before
the stack segment like:
| txt | dat | bss ... | *unmapedspace* | tstk | stk |
the segattach syscall only makes sure you dont map something after
or overlapping with the stack. so i think you could indeed map
something there and make the front fall off after exec().
you could map a readonly segment there and make the kernel crash
when it tries prepare the new stack.
segattach() also would try to allocate below the lowest possible stack
address when you pass 0 as the address.
maybe the tstk (ESEG) should be placed *after* the stack swaping
tstk and stk like:
#define TSTKTOP (VMAP-BY2PG)
#define TSTKSIZ 100
#define USTKTOP (TSTKTOP-TSTKSIZ)
#define USTKSIZE (16*1024*1024)
but maybe just making the checks in segattach take the tstk into
account is simpler...
--
cinap
next prev parent reply other threads:[~2013-03-15 20:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-15 17:03 erik quanstrom
2013-03-15 20:35 ` cinap_lenrek [this message]
2013-03-15 20:41 ` cinap_lenrek
2013-03-15 21:48 ` erik quanstrom
2013-03-15 21:51 ` erik quanstrom
2013-03-15 22:48 ` cinap_lenrek
2013-03-15 23:57 ` erik quanstrom
2013-03-16 0:11 ` cinap_lenrek
2013-03-17 1:56 ` erik quanstrom
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=6c7727bd06577062ffdbadcef28e33bf@rei2.9hal \
--to=cinap_lenrek@gmx.de \
--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).