Date: Tue, 3 May 2005 23:10:04 GMT From: Giorgos Keramidas <keramida@freebsd.org> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/80587: accept(2) can return EINVAL for undocumented reason Message-ID: <200505032310.j43NA4Us077191@freefall.freebsd.org>
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The following reply was made to PR kern/80587; it has been noted by GNATS.
From: Giorgos Keramidas <keramida@freebsd.org>
To: Arne H Juul <arnej@europe.yahoo-inc.com>
Cc: bug-followup@freebsd.org
Subject: Re: kern/80587: accept(2) can return EINVAL for undocumented reason
Date: Wed, 4 May 2005 02:00:22 +0300
On 2005-05-03 20:35, Arne H Juul <arnej@europe.yahoo-inc.com> wrote:
> We had a problem where a daemon wouldn't read commands on its socket;
> after some debugging we found that accept() on the socket didn't work
> (with errno EINVAL). According to man 2 accept this can only be
> caused by "listen(2) has not been called" but after more intensive
> debugging we couldn't figure out how that was possible in our program.
>
> Inspection of the actual kernel source for accept(2) however shows
> that it also returns EINVAL when the namelen argument is negative; it
> turns out the program had a stupid bug where the namelen was
> uninitialized causing accept() to fail unpredicably depending on stack
> contents. The following documentation fix would (hopefully) have
> saved us some time chasing down codepaths through listen().
True! The relevant bits in CURRENT are in uipc_syscalls.c (which you
already know, but I'm posting here for the audit trail):
281 static int
282 accept1(td, uap, compat)
...
290 {
...
307 if (namelen < 0)
308 return (EINVAL);
> .It Bq Er EINVAL
> .Xr listen 2
> has not been called on the socket descriptor.
> +.It Bq Er EINVAL
> +The
> +.Fa addrlen
> +argument is negative.
I think that documenting both cases in a single paragraph of accept(2)
is ok too:
.It Bq Er EINVAL
.Xr listen 2
-has not been called on the socket descriptor.
+has not been called on the socket descriptor or the
+.Fa addrlen
+argument is negative.
If this change to the diff is ok with you too, I'll see that it gets
committed.
- Giorgos
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