Real DNS resolution for getaddrinfo under -sNODERAWSOCKETS - #27693
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/etc/hosts entries (read through the emscripten FS) resolve synchronously, other hostnames resolve via node:dns, blocking where the calling stack can wait (a proxied pthread via PROXY_SYNC_ASYNC, ASYNCIFY/JSPI by suspending) and returning EAI_AGAIN otherwise. Results may be a linked list, which freeaddrinfo now frees in full.
…leAsync, support ASYNCIFY
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This gives
getaddrinfo()real name resolution under-sNODERAWSOCKETS. Split out from #27182, which also added a new asynchronous DNS API; this PR is only the change to the existing blocking API, allowing any async API work to follow separately.Previously every hostname resolved to a fake
172.29.x.xaddress, which is fine for the websocket proxy transport but not for real Node.js sockets, where the address has to be connectable.node:dns(which honors the host's/etc/hosts). The lookup is asynchronous, sogetaddrinfoblocks by returning a Promise where the calling stack can wait on it: a sync-proxied pthread (PROXY_SYNC_ASYNC, e.g.main()underPROXY_TO_PTHREAD), orASYNCIFY/JSPIby suspending throughAsyncify.handleAsync, which also holds a runtime keepalive so a user callback completing mid-lookup does not exit the runtime. Numeric addresses and errors still return synchronously, soJSPIdoes not pay a microtask on those.EAI_AGAINwithout starting a lookup.addrinfolinked list (multiple DNS records,AF_UNSPEC), andfreeaddrinfowalks the whole chain.Everything is gated on
NODERAWSOCKETS; without itgetaddrinfois unchanged.Implementation-wise
getaddrinfokeeps its existing body and returns either anEAI_*code or a Promise of one. The pthread proxy receive side now accepts a synchronous value from aPROXY_SYNC_ASYNCfunction (Promise.resolve(rtn).then(...)), so no wrapper is needed for the sync paths.Tested with
test_noderawsockets_dns(numeric,EAI_AGAINsingle-threaded), andtest_noderawsockets_dns_blocking{,_asyncify,_jspi}(multi-address lists across families, and a timer firing during the lookup underEXIT_RUNTIME).Made with AI assistance under my review