Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 10 Sep 2021 21:51:38 +0300
From:      Andriy Gapon <avg@FreeBSD.org>
To:        "net@FreeBSD.org" <net@FreeBSD.org>, hackers@FreeBSD.org
Subject:   recvmsg() "short receive" after FIONREAD
Message-ID:  <500a2272-c1b3-3f97-0096-9fe8117c4b95@FreeBSD.org>

next in thread | raw e-mail | index | archive | help


I observe a problem with the code that can be seen here:
https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/blob/master/src/modules/rtp/sap.c#L142

The code uses ioctl(FIONREAD) to check the size of available data in a socket.
Does / should this work?

Then the code calls recvmsg() on the socket with single vector with iov_len 
equal to the size obtained earlier.

But the return value from recvmsg() is smaller than the iov_len value.
In my test I see 215 vs expected 263 (so, the difference is 48).

Does this ring a bell to anyone?
I see this on a month old 14.0-CURRENT arm64.

-- 
Andriy Gapon



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?500a2272-c1b3-3f97-0096-9fe8117c4b95>