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<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal">This is my first post here. I need help with ASYNC_pause_job(). I’m writing an async engine to delegate certificate validation to a different process. Validation happens asynchronously through IPCs. To explain what I’m doing I’ll use some
“pseudo” code:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">// this happens in process #1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">ctx = OPENSSL_malloc(sizeof(async_engine_ctx_t));<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">ctx->job = ASYNC_get_current_job()<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">ctx->wait_ctx = ASYNC_get_wait_ctx(job)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">pipe(ctx->fds);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">ASYNC_WAIT_CTX_set_wait_fd(ctx->wait_ctx, ctx, ctx->fds[0], ctx, async_engine_cleanup_cb);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">async_validation_request(ctx->fds[1], cert, cert_len); // this starts async validation via IPC<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">printf(“pause”)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">ASYNC_pause_job();<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">printf(“resume”)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">read(ctx->fds[0], &validation_result, sizeof(validation_result));<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">For simplicity I omitted error checks (in my runs I have no error in any of the mentioned functions). When async response comes in, via IPC, what I do is:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">// this happens in process #1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">write(write_fd, &status, sizeof(status)); // I verified write_fd == ctx->fds[1]<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I see 2 different issues with this:<o:p></o:p></p>
<ol style="margin-top:0in" start="1" type="1">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">ASYNC_pause_job() can wake up before write(). It will then block on the read(), which is too bad in my single-threaded code.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">I fixed case 1 by making read() non-blocking, I then run ASYNC_pause_job() again and again until write() is actually performed. So now I hit another issue. Time between printf(“pause”)
and write() is ~100/200 milliseconds. However time between write() and printf(“resume”) is usually ~4.5 seconds and this way too much.<o:p></o:p></li></ol>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is there a reliable way (only when data is really ready) and a prompt way (in order of micro/milli-seconds) to wake up from ASYNC_pause_job()?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Many thanks, any help would be much appreciated.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Kind Regards,<o:p></o:p></p>
<p class="MsoNormal">Valerio Di Gregorio<span style="mso-fareast-language:#0C00"><o:p></o:p></span></p>
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