Steve,
You need to put select(ready to read or write) inside each (BOTH
SSL_read() and SSL_write()) of your while loops at the beginning, and
then cycle on WANT_READ or WANT_WRITE for BOTH SSL_read() and
SSL_write() loops.
You're getting high utilization because you are not putting select
inside the while loops.
Joe
Steven Young wrote:
Hello,
I'm writing a program which can be compiled either with SSL support or
without. In order to limit the amount of #ifdef'ing I have to put
throughout the rest of my program, I'm trying to wrap SSL_read and
SSL_write so they can be treated like read/write on a regular socket.
This is not meeting with much success.
In the non-SSL case, I do connect(), set it nonblocking, and start
select()ing on the fd(s) that I have connected to. This works okay.
In the SSL case, I connect(), create a new context with SSL_new,
set it nonblocking, do SSL_set_fd, then do
int ret;
[...]
do {
ret = SSL_connect(sslobject);
if(ret != 1)
err = ERR_get_error();
} while (ret != 1 && (err == SSL_ERROR_WANT_READ ||
err == SSL_ERROR_WANT_WRITE));
This part also seems to work okay.
The part where everything falls apart is in my read/write wrappers.
They look like this:
read_wrapper:
[...]
do {
ret = SSL_read(sslobject, buf, bufsz);
err = SSL_get_error(sslobject, ret);
} while (ret <= 0 && (err == SSL_ERROR_WANT_READ));
my write_wrapper looks pretty much the same, except s/read/write/,
s/READ/WRITE/.
This and variations on these themes have given me a number of novel
results, such as the read loop eating 100% CPU time as SSL_read starts
to always return ret = -1 and error = SSL_ERROR_WANT_READ. SSL_write
seems to be behaving a bit better. I am mystefied as to why select()
would mark the fd as ready to read, and yet SSL_read returns nothing,
resulting in a 100% CPU loop.
Is there some other way I should be doing this? I have tried putting
if(ret <= 0 && (err == SSL_ERROR_WANT_WRITE))
SSL_write(sslobject, NULL, 0):
in my read loop after the err = ... statement, but it didn't do
anything.
If anybody can make any suggestions, or even point me to an example
of how this should be done, I would be much obliged. Is there an
IRC channel for OpenSSL support?
Thanks,
Steve.
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______________________________________________________________________
OpenSSL Project http://www.openssl.org
User Support Mailing List openssl-users@openssl.org
Automated List Manager [EMAIL PROTECTED]
