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Re: [Patches] lio_listio() doesn't validate the aio_lio_opcode?

On 2012å02æ17æ 23:31, Carlos O'Donell wrote:

On Fri, Feb 17, 2012 at 9:43 AM, Khem Raj<raj.khem@xxxxxxxxx>  wrote:

On Fri, Feb 17, 2012 at 1:46 AM, Kang Kai<Kai.Kang@xxxxxxxxxxxxx>  wrote:

Hi All,

If pass a invalid aio_lio_opcode to lio_listio() with mode LIO_NOWAIT, it
return 0 which means success. Is this the proper action for invalid
aio_lio_opcode?

I check the source code ./sysdeps/pthread/lio_listio.c Line 81:

if (list[cnt] != NULL&&  list[cnt]->aio_lio_opcode != LIO_NOP)

it just checks aio_lio_opcode is not LIO_NOP then enqueue the request? I
wonder this is buggy.

for aio_lio_opcode posix says "The supported operations are LIO_READ,
LIO_WRITE, and LIO_NOP"

but it does not say what should happen if the value it not one of the above
so IMO its not a bug but falls into undefined behavior.

Hi Carlos,

Thanks a lot.


The value gets passed down to the AIO layer.

In sysdeps/pthread/aio_misc.c we have code to process LIO_READ,
LIO_WRITE, LIO_DYSNC, LIO_SYNC and then:
~~~
           else
             {
               /* This is an invalid opcode.  */
               aiocbp->aiocb.__return_value = -1;
               __set_errno (EINVAL);
             }
~~~


Why don't set __error_code at same time?

Regards,
Kai


However, LIO_READ == LIO_WAIT, so your LIO_WAIT is processed as a LIO_READ.

Cheers,
Carlos.


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