From: Tomko <tomko@haha.com>
To: linux-kernel@vger.kernel.org
Subject: Why system call need to copy the date from the userspace before using it
Date: Wed, 13 Apr 2005 12:21:41 +0800 [thread overview]
Message-ID: <425C9E55.6010607@haha.com> (raw)
Hi all,
I am new to linux , hope someone can help me.
While i am reading the source code of the linux system call , i find
that the system call need to call copy_from_user() to copy the data from
user space to kernel space before using it . Why not use it directly as
the system call has got the address ? Furthermore , how to distinguish
between user space and kernel space ?
Thx a lot,
TOM
next reply other threads:[~2005-04-13 4:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-13 4:21 Tomko [this message]
2005-04-13 5:30 ` Why system call need to copy the date from the userspace before using it Vadim Lobanov
2005-04-13 10:29 ` Jan-Benedict Glaw
2005-04-13 10:43 ` Tomko
2005-04-13 11:10 ` Catalin Marinas
2005-04-14 2:10 ` Tomko
2005-04-14 2:18 ` David Schwartz
2005-04-14 14:05 ` Helge Hafting
2005-04-13 11:33 ` Benjamin Herrenschmidt
2005-04-13 11:59 ` Hacksaw
2005-04-13 12:40 ` Richard B. Johnson
2005-04-13 18:37 ` Theodore Ts'o
2005-04-13 19:20 ` Richard B. Johnson
2005-04-16 4:50 ` Hacksaw
2005-04-16 5:18 ` Vadim Lobanov
2005-04-16 8:30 ` Hacksaw
2005-04-16 19:35 ` Vadim Lobanov
2005-04-16 23:46 ` David Wagner
-- strict thread matches above, loose matches on Subject: below --
2005-04-13 6:48 Vadim Lobanov
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=425C9E55.6010607@haha.com \
--to=tomko@haha.com \
--cc=linux-kernel@vger.kernel.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