LibC: Implement recvmsg and sendmsg

These just wrap recvfrom and sendto so ancillary data is not supported

userspace/libraries/LibC/sys/socket.cpp

@@ -1,3 +1,6 @@
+#include <BAN/Debug.h>
+
+#include <errno.h>
 #include <pthread.h>
 #include <sys/socket.h>
 #include <sys/syscall.h>
@@ -33,7 +36,7 @@ int listen(int socket, int backlog)
 
 ssize_t recv(int socket, void* __restrict buffer, size_t length, int flags)
 {
-	pthread_testcancel();
+	// cancellation point in recvfrom
 	return recvfrom(socket, buffer, length, flags, nullptr, nullptr);
 }
 
@@ -53,7 +56,7 @@ ssize_t recvfrom(int socket, void* __restrict buffer, size_t length, int flags,
 
 ssize_t send(int socket, const void* message, size_t length, int flags)
 {
-	pthread_testcancel();
+	// cancellation point in sendto
 	return sendto(socket, message, length, flags, nullptr, 0);
 }
 
@@ -71,6 +74,74 @@ ssize_t sendto(int socket, const void* message, size_t length, int flags, const
 	return syscall(SYS_SENDTO, &arguments);
 }
 
+ssize_t	recvmsg(int socket, struct msghdr* message, int flags)
+{
+	if (CMSG_FIRSTHDR(message))
+	{
+		dwarnln("TODO: recvmsg ancillary data");
+		errno = ENOTSUP;
+		return -1;
+	}
+
+	size_t total_recv = 0;
+
+	for (int i = 0; i < message->msg_iovlen; i++)
+	{
+		const ssize_t nrecv = recvfrom(
+			socket,
+			message->msg_iov[i].iov_base,
+			message->msg_iov[i].iov_len,
+			flags,
+			static_cast<sockaddr*>(message->msg_name),
+			&message->msg_namelen
+		);
+
+		if (nrecv < 0)
+			return -1;
+
+		total_recv += nrecv;
+
+		if (static_cast<size_t>(nrecv) < message->msg_iov[i].iov_len)
+			break;
+	}
+
+	return total_recv;
+}
+
+ssize_t	sendmsg(int socket, const struct msghdr* message, int flags)
+{
+	if (CMSG_FIRSTHDR(message))
+	{
+		dwarnln("TODO: sendmsg ancillary data");
+		errno = ENOTSUP;
+		return -1;
+	}
+
+	size_t total_sent = 0;
+
+	for (int i = 0; i < message->msg_iovlen; i++)
+	{
+		const ssize_t nsend = sendto(
+			socket,
+			message->msg_iov[i].iov_base,
+			message->msg_iov[i].iov_len,
+			flags,
+			static_cast<sockaddr*>(message->msg_name),
+			message->msg_namelen
+		);
+
+		if (nsend < 0)
+			return -1;
+
+		total_sent += nsend;
+
+		if (static_cast<size_t>(nsend) < message->msg_iov[i].iov_len)
+			break;
+	}
+
+	return total_sent;
+}
+
 int socket(int domain, int type, int protocol)
 {
 	return syscall(SYS_SOCKET, domain, type, protocol);