Subject: Re: [PATCH 3/3] io_uring: Introduce getsockname io_uring cmd

From: Gabriel Krisman Bertazi <[email-masked]>
Date: Mon, 27 Oct 2025 17:20:16 -0400

Jens Axboe <[email-masked]> writes:

> On 10/24/25 9:49 AM, Gabriel Krisman Bertazi wrote:
>> Introduce a socket-specific io_uring_cmd to support
>> getsockname/getpeername via io_uring.  I made this an io_uring_cmd
>> instead of a new operation to avoid polluting the command namespace with
>> what is exclusively a socket operation.  In addition, since we don't
>> need to conform to existing interfaces, this merges the
>> getsockname/getpeername in a single operation, since the implementation
>> is pretty much the same.
>> 
>> This has been frequently requested, for instance at [1] and more
>> recently in the project Discord channel. The main use-case is to support
>> fixed socket file descriptors.
>
> Just two nits below, otherwise looks good!
>
>> diff --git a/io_uring/cmd_net.c b/io_uring/cmd_net.c
>> index 27a09aa4c9d0..092844358729 100644
>> --- a/io_uring/cmd_net.c
>> +++ b/io_uring/cmd_net.c
>> @@ -132,6 +132,28 @@ static int io_uring_cmd_timestamp(struct socket *sock,
>>  	return -EAGAIN;
>>  }
>>  
>> +static int io_uring_cmd_getsockname(struct socket *sock,
>> +				    struct io_uring_cmd *cmd,
>> +				    unsigned int issue_flags)
>> +{
>> +	const struct io_uring_sqe *sqe = cmd->sqe;
>> +
>
> Random newline.

Done, but this fix will totally ruin the diffstat.  :(

>
>> +	struct sockaddr_storage address;
>> +	struct sockaddr __user *uaddr;
>> +	int __user *ulen;
>> +	unsigned int peer;
>> +
>> +	uaddr = u64_to_user_ptr(READ_ONCE(sqe->addr));
>> +	ulen = u64_to_user_ptr(sqe->addr3);
>> +	peer = READ_ONCE(sqe->optlen);
>> +
>> +	if (sqe->ioprio || sqe->__pad1 || sqe->len || sqe->rw_flags)
>> +		return -EINVAL;
>
> Most/all prep handlers tend to check these first, then proceed with
> setting up if not set. Would probably make sense to mirror that here
> too.

Ack. will wait a few days for feedback on the network side before the
v2.

-- 
Gabriel Krisman Bertazi