Merge pull request #10308 from orezraey/fix/libkernel-socket-receive-measured-ps5

fix(libkernel): answer zero-length datagram receives and recvmsg flags as measured on a PS5

core/libs/prx/libkernel/Socket/src/Udp.cpp

@@ -716,6 +716,17 @@ int SetNonBlocking(Socket& socket) {
     socket.options.nonblocking = true;
     return 0;
 }
+bool ReadableNow(const Socket& socket) {
+    NativePollDescriptor entry{};
+    entry.fd = socket.value;
+#ifdef _WIN32
+    entry.events = POLLRDNORM;
+    return WSAPoll(&entry, 1, 0) > 0;
+#else
+    entry.events = POLLIN;
+    return ::poll(&entry, 1, 0) > 0;
+#endif
+}
 int ReceiveAnsweredHere(Socket& socket, std::uint64_t length) {
 #ifdef _WIN32
     {
@@ -723,7 +734,8 @@ int ReceiveAnsweredHere(Socket& socket, std::uint64_t length) {
         if (socket.receiveShut) return 0;
     }
 #endif
-    if (length != 0 || socket.type != 1) return -1;
+    if (length != 0) return -1;
+    if (socket.type != 1) return ReadableNow(socket) ? -1 : 0;
     sockaddr_storage peer{};
     socklen_t size = sizeof(peer);
     return ::getpeername(socket.value, reinterpret_cast<sockaddr*>(&peer), &size) == 0 ? 0 : NativeError();
@@ -1593,22 +1605,26 @@ std::int64_t APS5_VABI recvmsg_nid_postfix(int descriptor, GuestMsghdr* message,
         return Fail(55);
     }
     sockaddr_storage native{};
-    socklen_t size = sizeof(native);
-    if (const int waited = WaitForTransfer(*socket, false, flags)) return Fail(waited);
-    std::int64_t received = ::recvfrom(socket->value, buffer.data(), static_cast<int>(buffer.size()),
-        NativeReceiveFlags(flags, socket->type), reinterpret_cast<sockaddr*>(&native), &size);
-    if (received < 0) {
+    socklen_t size = 0;
+    std::int64_t received = 0;
+    if (total != 0 || socket->type == 1 || ReadableNow(*socket)) {
+        size = sizeof(native);
+        if (const int waited = WaitForTransfer(*socket, false, flags)) return Fail(waited);
+        received = ::recvfrom(socket->value, buffer.data(), static_cast<int>(buffer.size()),
+            NativeReceiveFlags(flags, socket->type), reinterpret_cast<sockaddr*>(&native), &size);
+        if (received < 0) {
 #ifdef _WIN32
-        if (!records || WSAGetLastError() != WSAEMSGSIZE) return Fail(NativeError());
-        received = static_cast<std::int64_t>(buffer.size());
+            if (!records || WSAGetLastError() != WSAEMSGSIZE) return Fail(NativeError());
+            received = static_cast<std::int64_t>(buffer.size());
 #else
-        return Fail(NativeError());
+            return Fail(NativeError());
 #endif
+        }
     }
-    header.flags = 0;
+    header.flags = flags;
     if (received > total) {
         received = total;
-        header.flags = 0x10;
+        header.flags |= 0x10;
     }
     std::size_t offset = 0;
     for (const auto& vector : vectors) {

core/libs/tests/GuestDatagramReceive.cpp

@@ -140,6 +140,21 @@ static void Check(bool net, bool from, int family) {
         std::this_thread::sleep_for(std::chrono::milliseconds(1));
     } while (std::chrono::steady_clock::now() < deadline);
     Require(result == 0 && byte == '!', "empty datagram");
+    if (!net) {
+        send("hello", 5);
+        const auto ready = std::chrono::steady_clock::now() + std::chrono::seconds(1);
+        do {
+            result = receive(&byte, 1, 2, nullptr, nullptr);
+            if (result >= 0 || *error != 35) break;
+            std::this_thread::sleep_for(std::chrono::milliseconds(1));
+        } while (std::chrono::steady_clock::now() < ready);
+        Require(result == 1, "wait for the datagram");
+        Require(receive(&byte, 0, 2, nullptr, nullptr) == 0 && receive(&byte, 1, 2, nullptr, nullptr) == 1, "a zero-length peek keeps the datagram");
+        Require(receive(&byte, 0, 0, nullptr, nullptr) == 0, "a zero-length receive returns 0");
+        Require(receive(&byte, 1, 0, nullptr, nullptr) < 0 && *error == 35, "a zero-length receive discards the datagram");
+        Require(fcntl_nid_postfix(receiver, 4, 2) == 0, "make receiver blocking");
+        Require(receive(&byte, 0, 0, nullptr, nullptr) == 0, "a zero-length receive on an empty queue returns 0 without waiting");
+    }
     Require(closeSocket(receiver) == 0, "close receiver");
     Require(closeSocket(sender) == 0, "close sender");
 }

core/libs/tests/GuestUdp.cpp

@@ -254,6 +254,9 @@ int main() {
     source.fill(0);
     unsigned char control[8]{};
     Msghdr incoming{source.data(), static_cast<std::uint32_t>(source.size()), pieces, 2, control, sizeof(control), -1};
+    Require(recvmsg_nid_postfix(receiver, &incoming, 2) == 14 && incoming.flags == 2);
+    incoming.nameLength = static_cast<std::uint32_t>(source.size());
+    incoming.controlLength = sizeof(control);
     Require(recvmsg_nid_postfix(receiver, &incoming, 0) == 14);
     Require(std::memcmp(first, "scat", 4) == 0 && std::memcmp(second, "ter gather", 10) == 0);
     Require(incoming.flags == 0 && incoming.controlLength == 0 && incoming.nameLength == 16 && source[1] == 2 && source[4] == 127);
@@ -262,9 +265,15 @@ int main() {
     char shortBuffer[5]{};
     Iovec single{shortBuffer, sizeof(shortBuffer)};
     Msghdr truncated{nullptr, 0, &single, 1, nullptr, 0, 0};
-    Require(recvmsg_nid_postfix(receiver, &truncated, 0) == 5);
-    Require(std::memcmp(shortBuffer, "scatt", 5) == 0 && truncated.flags == 0x10);
+    Require(recvmsg_nid_postfix(receiver, &truncated, 2) == 5 && truncated.flags == 0x12);
+    Require(recvmsg_nid_postfix(receiver, &truncated, 0x80) == 5);
+    Require(std::memcmp(shortBuffer, "scatt", 5) == 0 && truncated.flags == 0x90);
     Require(recvmsg_nid_postfix(receiver, &truncated, 0) == -1 && *__error_nid_postfix() == 35);
+    Iovec none{shortBuffer, 0};
+    Msghdr empty{nullptr, 0, &none, 1, nullptr, 0, -1};
+    Require(fcntl_nid_postfix(receiver, 4, 2) == 0);
+    Require(recvmsg_nid_postfix(receiver, &empty, 0) == 0 && empty.flags == 0);
+    Require(fcntl_nid_postfix(receiver, 4, 6) == 0);
     Msghdr oversized{nullptr, 0, parts, 1025, nullptr, 0, 0};
     Require(sendmsg_nid_postfix(sender, &oversized, 0) == -1 && *__error_nid_postfix() == 40);
     Require(recvmsg_nid_postfix(receiver, nullptr, 0) == -1 && *__error_nid_postfix() == 14);

docs/dev/debt/libSceNet.md

@@ -26,6 +26,7 @@
 
 ### Functional
 
+- [sceNetRecv/sceNetRecvfrom](../../../core/libs/prx/libSceNet/Export.cpp) (libSceNet) translate Windows WSAEMSGSIZE into the copied byte count for datagram sockets, including MSG_PEEK, and retain the sender address. This follows FreeBSD 11.4 recv(2) and Winsock's documented truncated-datagram behavior; the console measurement covered only libkernel_sys `recv` and `recvfrom`, not libSceNet.
 - [sceNetUsleep](../../../core/libs/prx/libSceNet/Export.cpp) (libSceNet) prints nothing for a negative count, where the console prints `[LIBNET] usleep <count>` to standard output before failing with `EINVAL`. What an interrupted sleep returns is unmeasured: AnyPS5 returns the result of libkernel's `sceKernelUsleep`, a cancellation point. The signed 32-bit count (the upper half of the register is ignored) and the 0 result were measured on a PS5 (firmware 13.60)
 - [sceNetIoctl](../../../core/libs/prx/libSceNet/Export.cpp) (libSceNet) - on a `sceNetSocket` socket only `FIONBIO` and `FIONREAD` are handled and other requests fail with `ENOTTY`, as in libkernel's `ioctl`, though FreeBSD 11.4's [`soo_ioctl`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/sys_socket.c#L156-L262) handles more; not measured on a console. [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/60c42b925c3d1e00008621b8587819999260ec31/src/core/libraries/net/net.cpp#L1839) (PS4) returns `EINVAL` for other requests. `FIONBIO` sets `SO_NBIO`, assumed to be `soo_ioctl`'s `SS_NBIO`. `FIONREAD` asks the host, which on Linux counts only the next datagram where `soo_ioctl` counts all. Libkernel's own sockets go to its `ioctl`; other descriptors get `EBADF`.
 - [sceNetResolverStartAton6](../../../core/libs/prx/libSceNet/Export.cpp) (libSceNet) reverse-resolves a 16-byte IPv6 address through the host resolver (`getnameinfo` with `NI_NAMEREQD`) into the caller's buffer of `len` bytes, as `sceNetResolverStartAton` does for IPv4. The `(rid, addr, hostname, len, timeout, retry, flags)` signature comes from [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/5dfdb4b0b166e83dc9ae275001afb695f12c7174/src/SharpProspero/Interop/Net/Socket.cs#L992-L997). An address with no name, or a name longer than `len - 1` bytes, fails with `RESOLVER_ENODNS` (`0x804101E1`) and leaves the buffer untouched; whether the console truncates instead is not verified. Abort flag 2 (ATON preservation) fails the next call with `EINTR` as it does `sceNetResolverStartAton`. Timeout and retry are ignored, and any nonzero flags throw because their meaning is unknown

docs/dev/debt/libkernel.md

@@ -202,11 +202,11 @@
 - [nmount](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) throws: mounting file systems is not supported. Prospero Themes (PPSA90210) imports it and fails to load without it; it opens its theme library without calling it, and its strings (`/dev/ssd0.system_ex`, `/system_ex`, `exfatfs`, `fstype`, `fspath`, `from`, `ignoreacl`) point to remounting the console's `/system_ex` partition to write theme files there.
 - [socketpair](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) - the pair is the host's `AF_UNIX` pair on Linux and macOS and, on Windows, a loopback TCP connection for `SOCK_STREAM` or two connected UDP sockets for `SOCK_DGRAM`; `SOCK_SEQPACKET` throws on Windows and macOS, which has no such `AF_UNIX` pair. A datagram sent to a full receiver gets `ENOBUFS` on the console, waits or gets `EAGAIN` on Linux and is dropped on Windows, and on Windows a datagram `recv` after the peer closed reports `ECONNRESET` instead of the console's `ENOTCONN`, and the first stream `send` after the peer closed succeeds on the loopback connection, where the console returns `EPIPE`; the sends after it report `EPIPE`. `read` and `write` on a pair end go to the host like on every guest socket. `getpeername` on a pair end succeeds after the peer closed, where the console returns `ENOTCONN`, and `connect`, `bind` and `sendto` with an address on a pair end report an address-family error instead of the console's `EISCONN`. On Windows `poll` on a stream end reports `POLLIN` after the peer's `shutdown(SHUT_WR)` or `close`, as the console does after a `shutdown(SHUT_WR)`; after the peer's `close` the console reports `POLLIN` with `POLLHUP`, because `unp_drop` disconnects the other end, and the loopback connection cannot tell that from a shutdown, so no `POLLHUP` is reported
 - Guest sockets on macOS ([the equeue wait, kevent, fstat and ioctl](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp), [gethostbyname](../../../core/libs/prx/libScePosixForWebKit/Resolver.cpp)): macOS has no `ppoll`, so the wait uses `poll` with the timeout rounded up to a millisecond; it has no `POLLRDHUP`, so a stream that the peer closed is found by peeking one byte when it is readable; `FIONREAD` on a datagram socket, and the byte count that `fstat` and `kevent` report for it, is `SO_NREAD`, the size of the next datagram, because macOS adds the source address to `FIONREAD`; and `gethostbyname` replaces `gethostbyname_r`, which macOS lacks.
-- [UDP recv/recvfrom](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) and [sceNetRecv/sceNetRecvfrom](../../../core/libs/prx/libSceNet/Export.cpp) translate Windows WSAEMSGSIZE into the copied byte count for datagram sockets, including MSG_PEEK, and retain the sender address. This follows FreeBSD 11.4 recv(2) and Winsock's documented truncated-datagram behavior; console behavior and existing title impact are unverified.
 - [recvmsg](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) loses received stream data on an output copy fault: outputs are checked after the host receive. FreeBSD 11.4 leaves unread stream data queued, though it also drops a datagram on a copy fault ([`soreceive_dgram`](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/kern/uipc_socket.c#L2308-L2312), [`soreceive_generic`](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/kern/uipc_socket.c#L1758-L1774)). A Linux `process_vm_readv` or `process_vm_writev` failure other than `EFAULT` throws
 - [MSG_DONTWAIT](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) in `send`, `sendto`, `sendmsg`, `recv`, `recvfrom` and `recvmsg` makes that one call non-blocking through the host's `MSG_DONTWAIT`, as FreeBSD 11.4's `soreceive_generic` returns `EWOULDBLOCK` for it (`sys/kern/uipc_socket.c`). Winsock has no per-call non-blocking flag, so on Windows the call first asks `WSAPoll` with a zero timeout whether the socket is ready and fails with `EAGAIN` when it is not. The check and the transfer are two host calls: a second thread that takes the data in between can leave a `recv` blocked, and a `send` of more bytes than the socket buffer holds can still block until it has sent them, where FreeBSD's `sosend_generic` returns a partial count
 - [MSG_WAITALL](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) in `recv`, `recvfrom` and `recvmsg` on a stream socket is passed to the host, which returns when the buffer is full, the peer closes or an error occurs, as FreeBSD 11.4's [`soreceive_generic`](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/kern/uipc_socket.c#L1855-L1860) does; a datagram socket ignores it. It is not measured on a console, a nonblocking socket and a call that also passes `MSG_PEEK` follow the host's rules, and `SO_RCVTIMEO` bounds only the wait for the first data. Any other flag still fails with `EOPNOTSUPP`.
-- [recv and recvfrom](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) answer without the host a zero-length receive on a stream socket (0, or `ENOTCONN` when it is not connected, [L1566-L1578](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/kern/uipc_socket.c#L1566-L1578)) and, on Windows only, a receive on a socket whose read side `shutdown` closed (0, as [`soreceive_generic`](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/kern/uipc_socket.c#L1556-L1562) returns at `SBS_CANTRCVMORE`); Winsock fails the second with `EPIPE` and blocks on the first. Linux and macOS still return data buffered before the `shutdown`, where FreeBSD discards it. `recvmsg` still asks the host in both cases. Not measured on a console.
+- [recv and recvfrom](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) answer some cases without the host. A zero-length receive on a stream socket returns 0, or `ENOTCONN` when it is not connected ([L1566-L1578](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/kern/uipc_socket.c#L1566-L1578)), as on a PS5 (firmware 13.60). On an empty datagram socket it returns 0 at once; the console was measured only with `MSG_DONTWAIT`, and the blocking case follows FreeBSD 11.4's `soreceive_dgram`, which returns 0 before waiting. `recvmsg` answers the empty datagram socket the same way but asks the host in the stream cases. A datagram another thread takes after the check makes a zero-length receive wait
+- [recv and recvfrom after `shutdown(SHUT_RD)`](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) return 0 on Windows ([`soreceive_generic`](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/kern/uipc_socket.c#L1556-L1562)) where Winsock fails with `EPIPE`; Linux and macOS still return data buffered before it, which the console discards.
 - [send, sendto](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) - send and sendto without an address on an unconnected datagram socket map Windows `WSAENOTCONN` to FreeBSD's `EDESTADDRREQ` (39).
 - [bind, connect, sendto](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) check a socket address length as FreeBSD 11.4's [`getsockaddr`](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/kern/uipc_syscalls.c) and the `sa_len` test of `tcp_usr_connect` and `in_pcbconnect` do: below 2 or an `AF_INET` address below 16 or an `AF_INET6` address below 28 bytes fails with `EINVAL`, above 255 with `ENAMETOOLONG`. `sendto` does not check an address longer than `sockaddr_in` on an `AF_INET` datagram socket, where `udp_output` answers `EINVAL` unless the socket has a local address and port and the destination is neither `INADDR_ANY` nor `INADDR_BROADCAST`, nor on an unconnected stream socket, which FreeBSD connects implicitly through `tcp_connect` and its length test. An address of another family still fails with `EAFNOSUPPORT`, as the console's behaviour for it is not known. None of this was measured on a console.
 - [read, write and vector I/O](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) on a guest socket use `recv` and `send` without flags; `sceKernelReadv` and `sceKernelWritev` gather or scatter through one socket operation, preserving stream short reads and datagram boundaries. The positioned `pread`, `pwrite`, `preadv` and `pwritev` forms, and their `sceKernel` forms, return `ESPIPE` for an open guest socket and `EBADF` for a closed one. `EPIPE` from a write raises the host's `SIGPIPE` on Linux unless the socket has `SO_NOSIGPIPE` set, and the guest cannot ignore it: `signal(SIGPIPE, SIG_IGN)` and `sigaction` record the disposition, as they do for every number from 1 to 128, but only the six signals with host equivalents (2, 4, 6, 8, 11 and 15) take effect on the host or are delivered, so the host `SIGPIPE` is not stopped; nothing is raised on Windows; a `write` longer than `INT_MAX` bytes is `EMSGSIZE` where the console sends it. AIO on a guest socket still goes to the host, which has no such descriptor