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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