openssl: avoid undefined behavior on empty SSL_write

SSL_write(3ssl) manpage has this in the WARNINGS section:

       When calling SSL_write() with num=0 bytes to be sent the
       behaviour is undefined.

And indeed, the new test case demonstrates failures when
empty strings are used.  So, match the behavior of IO#write,
IO#write_nonblock, and IO#syswrite by returning zero, as the
OpenSSL::SSL::SSLSocket API already closely mimics the IO one.

* ext/openssl/ossl_ssl.c (ossl_ssl_write_internal):
  avoid undefined behavior
* test/openssl/test_pair.rb (test_write_zero): new test
  [ruby-core:76751] [Bug #12660]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55822 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

0 files changed, 0 insertions, 0 deletions