Re: [patch] recv.2: Mention SOCK_SEQPACKET in MSG_TRUNC flag description

[Vladislav Ivanishin <vlad@ispras.ru>]

unix_seqpacket_recvmsg() calls unix_dgram_recvmsg() which handles
MSG_TRUNC. This has been the case since the handling was added in
9f6f9af7694ede6314bed281eec74d588ba9474f; see net/unix/af_unix.c:

static int unix_seqpacket_recvmsg([...])
{
        [...]
	return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
}

The sequential-packet socket type seems to have been left out from the
description by an oversight.

Signed-off-by: Vladislav Ivanishin <vlad@ispras.ru>
---

Hi Alex,

On Sun, Dec 11 2022, Alejandro Colomar <alx.manpages@gmail.com> wrote:
> Hi Vladislav,
>
> On 11/27/22 11:38, Vladislav Ivanishin wrote:
>> unix_seqpacket_recvmsg() calls unix_dgram_recvmsg() which handles
>> MSG_TRUNC. This has been the case since the support for this flag was
>> implemented in the latter; the sequential-packet socket type seems to
>> have been left out from the description by an oversight.
>> Signed-off-by: Vladislav Ivanishin<vlad@ispras.ru>
>
> Could you please point to the relevant kernel commits, or quote the relevant
> lines of code, in the commit message?
>
> Thanks,
>
> Alex
    
Sure, here's an updated version.

Vlad

 man2/recv.2 | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/man2/recv.2 b/man2/recv.2
index 5298a2745..81cd1957c 100644
--- a/man2/recv.2
+++ b/man2/recv.2
@@ -226,7 +226,8 @@ subsequent receive call will return the same data.
 For raw
 .RB ( AF_PACKET ),
 Internet datagram (since Linux 2.4.27/2.6.8),
-netlink (since Linux 2.6.22), and UNIX datagram
+netlink (since Linux 2.6.22),
+and UNIX datagram as well as sequenced-packet
 .\" commit 9f6f9af7694ede6314bed281eec74d588ba9474f
 (since Linux 3.4) sockets:
 return the real length of the packet or datagram,
-- 
2.39.1