From owner-freebsd-emulation@FreeBSD.ORG  Fri May 20 16:58:41 2005
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Date: Fri, 20 May 2005 11:58:35 -0500
From: Dan Nelson <dnelson@allantgroup.com>
To: Martin Cracauer <cracauer@cons.org>
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cc: freebsd-emulation@freebsd.org
Subject: Re: System call tracing in Linuxulator
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In the last episode (May 20), Martin Cracauer said:
> Didn't we use top have a linux-strace port?
> 
> It seems that there is currently no stracing tool which would resolve
> Linux system calls to some text description.
> 
> Using the strace Linux binary fails with an invalid argument to
> ptrace:
> ./strace /compat/linux/bin/cat 
> execve("/compat/linux/bin/cat", ["/compat/linux/bin/cat"], [/* 56 vars
> */]) = 0
> trace: ptrace(PTRACE_SYSCALL, ...): Invalid argument
> 
> FreeBSD truss of the above strace ends with:
> linux_ptrace(0x18,0x17c41,0x1,0x0)               ERR#22 'Invalid argument'
> trace: ptrace(PTRACE_SYSCALL, ...): Invalid argument

I don't think you can trace a program that's tracing another program.

> What are people using these days?

I just use truss.  It understands the linux syscalls just fine.

-- 
	Dan Nelson
	dnelson@allantgroup.com