Fix unix writev

Author: nekohasekai

common/bufio/vectorised_unix.go

@@ -27,35 +27,36 @@ func (w *SyscallVectorisedWriter) WriteVectorised(buffers []*buf.Buffer) error {
 	for _, buffer := range buffers {
 		iovecList = append(iovecList, buffer.Iovec(buffer.Len()))
 	}
+	if cap(iovecList) > cap(w.iovecList) {
+		w.iovecList = iovecList[:0]
+	}
 	var innerErr unix.Errno
 	err := w.rawConn.Write(func(fd uintptr) (done bool) {
+		writeIovecList := iovecList
 		for {
 			var r0 uintptr
 			//nolint:staticcheck
-			r0, _, innerErr = unix.RawSyscall(unix.SYS_WRITEV, fd, uintptr(unsafe.Pointer(&iovecList[0])), uintptr(len(iovecList)))
+			r0, _, innerErr = unix.RawSyscall(unix.SYS_WRITEV, fd, uintptr(unsafe.Pointer(&writeIovecList[0])), uintptr(len(writeIovecList)))
 			writeN := int(r0)
 			for writeN > 0 {
 				if buffers[0].Len() > writeN {
 					buffers[0].Advance(writeN)
-					iovecList[0] = buffers[0].Iovec(buffers[0].Len())
+					writeIovecList[0] = buffers[0].Iovec(buffers[0].Len())
 					break
 				} else {
 					writeN -= buffers[0].Len()
 					buffers[0].Release()
 					buffers = buffers[1:]
-					iovecList = iovecList[1:]
+					writeIovecList = writeIovecList[1:]
 				}
 			}
-			if innerErr == unix.EINTR || (innerErr == 0 && len(iovecList) > 0) {
+			if innerErr == unix.EINTR || (innerErr == 0 && len(writeIovecList) > 0) {
 				continue
 			}
 			return innerErr != unix.EAGAIN
 		}
 	})
 	common.ClearArray(iovecList)
-	if cap(iovecList) > cap(w.iovecList) {
-		w.iovecList = iovecList[:0]
-	}
 	if innerErr != 0 {
 		err = os.NewSyscallError("SYS_WRITEV", innerErr)
 	}
@@ -70,7 +71,10 @@ func (w *SyscallVectorisedPacketWriter) WriteVectorisedPacket(buffers []*buf.Buf
 	for _, buffer := range buffers {
 		iovecList = append(iovecList, buffer.Iovec(buffer.Len()))
 	}
-	var innerErr error
+	if cap(iovecList) > cap(w.iovecList) {
+		w.iovecList = iovecList[:0]
+	}
+	var innerErr unix.Errno
 	err := w.rawConn.Write(func(fd uintptr) (done bool) {
 		var msg unix.Msghdr
 		name, nameLen := ToSockaddr(destination.AddrPort())
@@ -89,11 +93,8 @@ func (w *SyscallVectorisedPacketWriter) WriteVectorisedPacket(buffers []*buf.Buf
 		}
 	})
 	common.ClearArray(iovecList)
-	if cap(iovecList) > cap(w.iovecList) {
-		w.iovecList = iovecList[:0]
-	}
-	if innerErr != nil {
-		err = innerErr
+	if innerErr != 0 {
+		err = os.NewSyscallError("SYS_SENDMSG", innerErr)
 	}
 	return err
 }