ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read) { size_t offset = 0; int err; if (qemu_in_coroutine()) { if (do_read) { return qemu_co_recv(fd, buffer, size); } else { return qemu_co_send(fd, buffer, size); } } while (offset < size) { ssize_t len; if (do_read) { len = qemu_recv(fd, buffer + offset, size - offset, 0); } else { len = send(fd, buffer + offset, size - offset, 0); } if (len < 0) { err = socket_error(); /* recoverable error */ if (err == EINTR || err == EAGAIN) { continue; } /* unrecoverable error */ return -err; } /* eof */ if (len == 0) { break; } offset += len; } return offset; }