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    OpenSSL: multi interface handshake could hang · 77cfeadf
    Daniel Stenberg 提交于
    John-Mark Bell filed bug #3000052 that identified a problem (with
    an associated patch) with the OpenSSL handshake state machine
    when the multi interface is used:
    Performing an https request using a curl multi handle and using
    select or epoll to wait for events results in a hang. It appears
    that the cause is the fix for bug #2958179, which makes
    ossl_connect_common unconditionally return from the step 2 loop
    when fetching from a multi handle.
    When ossl_connect_step2 has completed, it updates
    connssl->connecting_state to ssl_connect_3. ossl_connect_common
    will then return to the caller, as a multi handle is in
    use. Eventually, the client code will call curl_multi_fdset to
    obtain an updated fdset to select or epoll on. For https
    requests, curl_multi_fdset will cause https_getsock to be called.
    https_getsock will only return a socket handle if the
    connecting_state is ssl_connect_2_reading or
    ssl_connect_2_writing.  Therefore, the client will never obtain a
    valid fdset, and thus not drive the multi handle, resulting in a