LibCore: Add syscall wrappers for sendfd() and recvfd()

Userland/Libraries/LibCore/System.cpp

@@ -11,6 +11,7 @@
 #include <fcntl.h>
 #include <stdarg.h>
 #include <sys/mman.h>
+#include <sys/socket.h>
 #include <unistd.h>
 
 #define HANDLE_SYSCALL_RETURN_VALUE(syscall_name, rc, success_value) \
@@ -49,6 +50,21 @@ ErrorOr<Array<int, 2>> pipe2(int flags)
         return Error::from_syscall("pipe2"sv, -errno);
     return fds;
 }
+
+ErrorOr<void> sendfd(int sockfd, int fd)
+{
+    if (::sendfd(sockfd, fd) < 0)
+        return Error::from_syscall("sendfd"sv, -errno);
+    return {};
+}
+
+ErrorOr<int> recvfd(int sockfd, int options)
+{
+    auto fd = ::recvfd(sockfd, options);
+    if (fd < 0)
+        return Error::from_syscall("recvfd"sv, -errno);
+    return fd;
+}
 #endif
 
 ErrorOr<void> sigaction(int signal, struct sigaction const* action, struct sigaction* old_action)

Userland/Libraries/LibCore/System.h

@@ -16,6 +16,8 @@ namespace Core::System {
 ErrorOr<void> pledge(StringView promises, StringView execpromises = {});
 ErrorOr<void> unveil(StringView path, StringView permissions);
 ErrorOr<Array<int, 2>> pipe2(int flags);
+ErrorOr<void> sendfd(int sockfd, int fd);
+ErrorOr<int> recvfd(int sockfd, int options);
 #endif
 
 ErrorOr<void> sigaction(int signal, struct sigaction const* action, struct sigaction* old_action);