Implement recvmmsg and sendmmsg - #27395
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lgtm although I would still expect the stubs for these syscalls to be removed (and also the syscalls themselves the syscalls.h, etc).
Ideally I would love to see the bugfix land first/separately, but its also not a big deal if testing in isolation is too difficult.
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Sure, I've gone ahead and split out the bugfixes into #27399. |
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This fixes three issues in the `recvmsg` syscall implementation for sockets, split out separately from #27395 per review feedback. The bugs: * Datagram data was written at the wrong offsets when scattered across multiple iovecs — `HEAPU8.set(buf, iovbase + bytesRead)` skipped ahead by the bytes already read into previous iovecs, corrupting all iovecs after the first. * `msg_namelen` was not updated to reflect the actual source address size. * `msg_controllen` and `msg_flags` were left untouched rather than zeroed, leaving callers reading uninitialized values as control data / flags. Adds `sockets.test_noderawsockets_udp_recvmsg` covering a datagram scattered across two iovecs along with the msghdr output fields, verified failing before the fix.
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sbc100
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Jul 22, 2026
Implements recvmmsg and sendmmsg in musl in terms of recvmsg and sendmsg, removing the now-unreferenced __syscall_recvmmsg and __syscall_sendmmsg stubs and syscall definitions.
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This implements
recvmmsgandsendmmsg, which were previouslyENOSYSstubs.Per review feedback, the implementations now live in musl's
sendmmsg.candrecvmmsg.crather than the syscall stubs:sendmmsg.calready contained the emulation loop (previously gated behindLONG_MAX > INT_MAX), which is now also enabled under__EMSCRIPTEN__, andrecvmmsg.cgains an equivalentrecvmsgloop supportingMSG_WAITFORONE(timeouts reportENOSYS).Since nothing references the syscalls anymore, the
__syscall_recvmmsg/__syscall_sendmmsgsurface is removed entirely: theUNIMPLEMENTEDstubs, theSYS_mappings inarch/emscripten/bits/syscall.h, the declarations inemscripten/syscalls.h, and theirnative_sigs.pyentries.The
recvmsgmsghdr output fixes previously bundled here were split out into #27399.Adds
sockets.test_noderawsockets_mmsgbatching two datagrams out viasendmmsgand receiving them back in a singlerecvmmsgcall.Made with AI assistance under my review