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From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: Re: About intercepting linux system call
Date: Fri, 28 Jan 2005 02:10:36 +0000	[thread overview]
Message-ID: <16889.40732.94252.216203@napali.hpl.hp.com> (raw)
In-Reply-To: <b3b26beb05012620543066d40@mail.gmail.com>

>>>>> On Fri, 28 Jan 2005 10:04:33 +0800, JinShan Xiong <jinshan.xiong@gmail.com> said:

  JinShan> Hi David, I don't know how to use the stub code, I have
  JinShan> tried to copy it to overload sys_gettimeofday(), like this,

  JinShan>  memcpy(sys_call_table[__NR_gettimeofday - 1024],
  JinShan> new_time_stub, 32),

  JinShan> it crashed the kenrel also.

  JinShan> Please help me!

sys_call_table[__NR_gettimeofday - 1024] would have to be set to the
entry-point of new_time_stub.  If you declare new_time_stub as a
function, you'd have to do this like so:

	extern void new_time_stub (whatever...);
	struct fptr { void *ip, void *gp };

	sys_call_table[__NR_gettimeofday - 1024] 		((struct fptr *) &new_time_stub)->ip;

  --david


  parent reply	other threads:[~2005-01-28  2:10 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-27  4:54 About intercepting linux system call JinShan Xiong
2005-01-27  5:27 ` Randy.Dunlap
2005-01-27  5:32 ` David Mosberger
2005-01-27  7:17 ` JinShan Xiong
2005-01-27 12:29 ` JinShan Xiong
2005-01-28  2:04 ` JinShan Xiong
2005-01-28  2:10 ` David Mosberger [this message]
2005-01-28  4:05 ` JinShan Xiong

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