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Re: [LTP] [PATCH] ioctl01: change the errno to ENOTTY when passed an invalid command
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From: Wanlong G. <gao...@cn...> - 2012-11-01 08:48:44
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On 11/01/2012 04:05 PM, Jan Stancek wrote:
>
>
> ----- Original Message -----
>> From: "Wanlong Gao" <gao...@cn...>
>> To: "LTP" <ltp...@li...>
>> Cc: "sanil kumar" <san...@hu...>, "Mike Frysinger" <va...@ge...>, "shyju pv" <shy...@hu...>,
>> "max maxiansheng" <max...@hu...>
>> Sent: Thursday, 1 November, 2012 5:00:19 AM
>> Subject: [LTP] [PATCH] ioctl01: change the errno to ENOTTY when passed an invalid command
>>
>> As linus said at the below commit,
>> commit 07d106d0a33d6063d2061305903deb02489eba20
>> Author: Linus Torvalds <tor...@li...>
>> Date: Thu Jan 5 15:40:12 2012 -0800
>>
>> vfs: fix up ENOIOCTLCMD error handling
>>
>> We're doing some odd things there, which already messes up
>> various users
>> (see the net/socket.c code that this removes), and it was going
>> to add
>> yet more crud to the block layer because of the incorrect error
>> code
>> translation.
>>
>> ENOIOCTLCMD is not an error return that should be returned to
>> user mode
>> from the "ioctl()" system call, but it should *not* be translated
>> as
>> EINVAL ("Invalid argument"). It should be translated as ENOTTY
>> ("Inappropriate ioctl for device").
>>
>> That EINVAL confusion has apparently so permeated some code that
>> the
>> block layer actually checks for it, which is sad. We continue to
>> do so
>> for now, but add a big comment about how wrong that is, and we
>> should
>> remove it entirely eventually. In the meantime, this tries to
>> keep the
>> changes localized to just the EINVAL -> ENOTTY fix, and removing
>> code
>> that makes it harder to do the right thing.
>>
>> Signed-off-by: Linus Torvalds <tor...@li...>
>>
>> Return ENOTTY is right. And with the tty driver change with below
>> commit,
>> commit bbb63c514a3464342967237a51a21ea8f61ab951
>> Author: Wanlong Gao <gao...@cn...>
>> Date: Mon Aug 27 15:23:12 2012 +0800
>>
>> drivers:tty:fix up ENOIOCTLCMD error handling
>>
>> At commit 07d106d0, Linus pointed out that ENOIOCTLCMD should be
>> translated as ENOTTY to user mode.
>> For example:
>> fd = open("/dev/tty", O_RDWR);
>> ioctl(fd, -1, &argp);
>>
>> then the errno should be ENOTTY but not EINVAL.
>>
>> Signed-off-by: Wanlong Gao <gao...@cn...>
>> Acked-by: Alan Cox <al...@li...>
>> Signed-off-by: Greg Kroah-Hartman <gr...@li...>
>>
>> The tty driver will return the right ENOTTY in upstream kernel when
>> passed a invalid ioctl command, so we fixed the LTP test case to
>> suit this return value change.
>> ---
>> testcases/kernel/syscalls/ioctl/ioctl01.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/testcases/kernel/syscalls/ioctl/ioctl01.c
>> b/testcases/kernel/syscalls/ioctl/ioctl01.c
>> index 8b044e7..ef64896 100644
>> --- a/testcases/kernel/syscalls/ioctl/ioctl01.c
>> +++ b/testcases/kernel/syscalls/ioctl/ioctl01.c
>> @@ -87,7 +87,7 @@ struct test_case_t {
>> &fd, TCGETA, (struct termio *)-1, EFAULT},
>> /* command is invalid */
>> {
>> - &fd, INVAL_IOCTL, &termio, EINVAL},
>> + &fd, INVAL_IOCTL, &termio, ENOTTY},
>
> Won't this break on older kernels? Can we test for kernel version with tst_kvercmp()?
Surely will, this is also a trouble on my side.
Does we treat this as a kernel bug or a kernel change?
I think if we treat it as a kernel bug, we needn't check the kernel version, while if
it just a kernel change, we need.
And, What's your opinion about this?
Thanks,
Wanlong Gao
>
> Regards,
> Jan
>
>> /* file descriptor is for a regular file */
>> {
>> &fd1, TCGETA, &termio, ENOTTY},
>> --
>> 1.8.0
>>
>>
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>
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