Re: [Qemu-devel] [PATCH] linux-user strace

[Andreas Schwab <schwab@suse.de>]

Stuart Anderson <anderson@netsweng.com> writes:

> On Fri, 20 Jul 2007, Andreas Schwab wrote:
>
>> Stuart Anderson <anderson@netsweng.com> writes:
>>
>>> Index: qemu/linux-user/syscall.c
>>> ===================================================================
>>> --- qemu.orig/linux-user/syscall.c	2007-07-19 01:42:43.000000000 -0400
>>> +++ qemu/linux-user/syscall.c	2007-07-19 01:43:18.000000000 -0400
>>> @@ -312,6 +312,11 @@
>>>      return (unsigned long)ret >= (unsigned long)(-4096);
>>>  }
>>>
>>> +char *target_strerror(int err)
>>> +{
>>> +	return strerror(host_to_target_errno(err));
>>> +}
>>> +
>>
>> That looks backwards.  strerror surely expects a host errno value, but
>> host_to_target_errno returns the errno value for the target, doesn't it?
>
> The function is called target_strerror() 8-).

That's the problem.  It does not return the string associated with the
target errno, but something else.

> It is used to display the errno string for the target, not the
> host.

But strerror interprets its argument as the host's errno value.  If
host_to_target_error maps ELOOP to TARGET_ELOOP, and TARGET_ELOOP
happens have be the same value as EBADFD, the function wil return
"Bad file descriptor" instead of "Too many levels of symbolic links".

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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