> Moved to openssl-users.
I wish you hadn't done that, because I was not subscribed to openssl-users.
I'm subscribed now, but I hope I haven't missed any messages related to this
between Saturday and today.
> On Fri, May 04, 2001 at 06:53:19PM -0400, Harrington, Thomas wrote:
> > I'm trying to do nonblocking writes via OpenSSL. Initially
> I cribbed the
> > following from mod_ssl:
> ...
> > But doing a 4kB write, followed by a ~30kB one, the second
> attempt would
> > consistently fail to write and get -1 back from SSL_write().
>
> It is not said that the write did fail. You need to call
> SSL_get_error()
> to find out more details. For nonblocking sockets I would say that the
> "failure" at this point is acceptable, because the 30kB write exceeds
> all internal and system buffer sizes, so that it may not be completed
> in the first attempt. I therefore expect SSL_get_error() to return
> SSL_ERROR_WANT_WRITE. You than select() the socket in question for
> "writable" condition and call SSL_write() again with the same
> arguments,
> until SSL_write() has finished.
OK, I did forget to mention that I call BIO_sock_should_retry() to see if I
should try and write again, and I do write again, and again, with the same
buffer and with the same failure.
I realize that a write call on a nonblocking socket may not write the data.
But as I said: I only get failures if I set nonblocking using ioctl(). If I
set nonblocking via fcntl(), there's no problem at all. It's not the fact
that SSL_write() doesn't write immediately that I'm puzzled about, it's the
fact that using fcntl() has a different effect on SSL_write() than using
ioctl() does, and I want to know why. That's my real question: What
difference does this make with openssl, and why? My code seems to work OK
right now, but since I'm relying on undocumented behavior I don't really
trust my fix yet.
Because you moved this over to openssl-users, I'll repost the original
question here. Since I was not subscribed to openssl-users until today, I
can only guess that it was not seen on this list.
----------
I'm trying to do nonblocking writes via OpenSSL. Initially I cribbed the
following from mod_ssl:
int iostate = 1;
rv = ioctl(sock, FIONBIO, (u_long*)&iostate);
rv = SSL_write(ssl, (char*)buf, len);
...
iostate = 0;
ioctl(sock, FIONBIO, (u_long*)&iostate);
But doing a 4kB write, followed by a ~30kB one, the second attempt would
consistently fail to write and get -1 back from SSL_write().
If I replace the ioctl() calls with fcntl() calls that should be equivalent,
it works every time. That is, set nonblocking as follows:
iostate = fcntl(sock, F_GETFL, 0);
iostate |= O_NDELAY;
rv = fcntl(sock, F_SETFL, iostate);
Why do I get different results here? I dug through the openssl code a bit
and can't see where this should make a difference. Buggy ioctl function,
maybe?
----------
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