Darryl Miles wrote:
Nanno Langstraat wrote:
It turns out that the problem does *not* directly involve
SSL_shutdown(), but it *is* attributable to OpenSSL, and specifically
OpenSSL's non-blocking shutdown semantics.
Okat thats cleared that up, it is indeed unrelated to the OP of this
thread. Please move replies (if any) to a new thread :).
Done. (slightly reluctantly because bad archiving websites will see it
as a new thread)
man 3 SSL_want
"Unlike SSL_get_error(3), which also evaluates the error queue, the
results are obtained by examining an internal state flag only. The
information must therefore only be used for normal operation under
non-blocking I/O."
Oh so we bypass all considerations and simply look at the "internal
state flag" because we are expected to be used for a "normal
operation". Well handling an end-of-stream condition is not a normal
operation or situation in my book for a start.
So the question remains, is end-of-stream considered an error
condition ? What does SSL_get_error() return in the situation in step
5 above ?
Can we agree on the convention that as long as no OpenSSL call has
returned -1, there is no error condition in effect, at least as far as
the application knows?
This is the case in the 100% CPU problem at hand.
But more detail is needed over step 2 in exactly what you are saying
as "process killed" is not the same condition as "TCP shutdown(RD)".
One results in a unusable socket (for any purpose, be it read or
write) and the other results in a still usable socket. So you can't
just get away with lumping those two situations as if either would do.
OK, the remote peer doing shutdown(RD) was an unfortunate entirely
fictional example of me. But I don't see that the issue is really
relevant: the local API confusion between OpenSSL and the application
exists whether the remote side sent a nice SSL shutdown notify message,
the remote process crashed + remote kernel closed the socket, or the
entire remote machine was unexpectedly hit by a 17-tonne meteor.
In all cases the local situation is the same: what OpenSSL calls is a
application developer faithfully following the documentation but not
aware of SSL internal details allowed to make?
Regards,
Nanno
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