From ff9a4fc336bca88fff4bee119c032905a5bab61f Mon Sep 17 00:00:00 2001 From: eldritch horrors Date: Mon, 22 Apr 2024 20:54:02 +0200 Subject: libstore: use curl_multi_{poll,wakeup} the previous solution to the wakeup problem (adding a pipe and passing it as an additional fd to curl_multi_wait) worked, but there have been builtin alternatives for this since 2020. not only do these save code, they're also a lot more likely to work natively on windows when needed Change-Id: Iab751b900997110a8d15de45ea3ab0c42f7e5973 --- src/libstore/filetransfer.cc | 33 ++++++++++----------------------- 1 file changed, 10 insertions(+), 23 deletions(-) (limited to 'src/libstore/filetransfer.cc') diff --git a/src/libstore/filetransfer.cc b/src/libstore/filetransfer.cc index 9ef220769..7d36796f4 100644 --- a/src/libstore/filetransfer.cc +++ b/src/libstore/filetransfer.cc @@ -504,11 +504,6 @@ struct curlFileTransfer : public FileTransfer Sync state_; - /* We can't use a std::condition_variable to wake up the curl - thread, because it only monitors file descriptors. So use a - pipe instead. */ - Pipe wakeupPipe; - std::thread workerThread; curlFileTransfer() @@ -523,9 +518,6 @@ struct curlFileTransfer : public FileTransfer curl_multi_setopt(curlm, CURLMOPT_MAX_TOTAL_CONNECTIONS, fileTransferSettings.httpConnections.get()); - wakeupPipe.create(); - fcntl(wakeupPipe.readSide.get(), F_SETFL, O_NONBLOCK); - workerThread = std::thread([&]() { workerThreadEntry(); }); } @@ -538,6 +530,12 @@ struct curlFileTransfer : public FileTransfer if (curlm) curl_multi_cleanup(curlm); } + void wakeup() + { + if (auto mc = curl_multi_wakeup(curlm)) + throw nix::Error("unexpected error from curl_multi_wakeup(): %s", curl_multi_strerror(mc)); + } + void stopWorkerThread() { /* Signal the worker thread to exit. */ @@ -545,7 +543,7 @@ struct curlFileTransfer : public FileTransfer auto state(state_.lock()); state->quit = true; } - writeFull(wakeupPipe.writeSide.get(), " ", false); + wakeup(); } void workerThreadMain() @@ -587,32 +585,21 @@ struct curlFileTransfer : public FileTransfer } /* Wait for activity, including wakeup events. */ - int numfds = 0; - struct curl_waitfd extraFDs[1]; - extraFDs[0].fd = wakeupPipe.readSide.get(); - extraFDs[0].events = CURL_WAIT_POLLIN; - extraFDs[0].revents = 0; long maxSleepTimeMs = items.empty() ? 10000 : 100; auto sleepTimeMs = nextWakeup != std::chrono::steady_clock::time_point() ? std::max(0, (int) std::chrono::duration_cast(nextWakeup - std::chrono::steady_clock::now()).count()) : maxSleepTimeMs; vomit("download thread waiting for %d ms", sleepTimeMs); - mc = curl_multi_wait(curlm, extraFDs, 1, sleepTimeMs, &numfds); + mc = curl_multi_poll(curlm, nullptr, 0, sleepTimeMs, nullptr); if (mc != CURLM_OK) - throw nix::Error("unexpected error from curl_multi_wait(): %s", curl_multi_strerror(mc)); + throw nix::Error("unexpected error from curl_multi_poll(): %s", curl_multi_strerror(mc)); nextWakeup = std::chrono::steady_clock::time_point(); /* Add new curl requests from the incoming requests queue, except for requests that are embargoed (waiting for a retry timeout to expire). */ - if (extraFDs[0].revents & CURL_WAIT_POLLIN) { - char buf[1024]; - auto res = read(extraFDs[0].fd, buf, sizeof(buf)); - if (res == -1 && errno != EINTR) - throw SysError("reading curl wakeup socket"); - } std::vector> incoming; auto now = std::chrono::steady_clock::now(); @@ -675,7 +662,7 @@ struct curlFileTransfer : public FileTransfer throw nix::Error("cannot enqueue download request because the download thread is shutting down"); state->incoming.push(item); } - writeFull(wakeupPipe.writeSide.get(), " "); + wakeup(); } #if ENABLE_S3 -- cgit v1.2.3