- const unsigned char *stop = buf+len;
- ssize_t cnt = 1;
- for (; buf<stop && (cnt=__syscall_write(f->fd, buf, len))>0; buf+=cnt);
- return len-(stop-buf);
+ struct iovec iovs[2] = {
+ { .iov_base = f->wbase, .iov_len = f->wpos-f->wbase },
+ { .iov_base = (void *)buf, .iov_len = len }
+ };
+ struct iovec *iov = iovs;
+ size_t rem = iov[0].iov_len + iov[1].iov_len;
+ int iovcnt = 2;
+ ssize_t cnt;
+ for (;;) {
+ if (libc.main_thread) {
+ pthread_cleanup_push(cleanup, f);
+ cnt = syscall_cp(SYS_writev, f->fd, iov, iovcnt);
+ pthread_cleanup_pop(0);
+ } else {
+ cnt = syscall(SYS_writev, f->fd, iov, iovcnt);
+ }
+ if (cnt == rem) {
+ f->wend = f->buf + f->buf_size;
+ f->wpos = f->wbase = f->buf;
+ return len;
+ }
+ if (cnt < 0) {
+ f->wpos = f->wbase = f->wend = 0;
+ f->flags |= F_ERR;
+ return iovcnt == 2 ? 0 : len-iov[0].iov_len;
+ }
+ rem -= cnt;
+ if (cnt > iov[0].iov_len) {
+ f->wpos = f->wbase = f->buf;
+ cnt -= iov[0].iov_len;
+ iov++; iovcnt--;
+ } else if (iovcnt == 2) {
+ f->wbase += cnt;
+ }
+ iov[0].iov_base = (char *)iov[0].iov_base + cnt;
+ iov[0].iov_len -= cnt;
+ }