1#include "stdio_impl.h"
2#include <sys/uio.h>
3
4size_t __stdio_write(FILE *f, const unsigned char *buf, size_t len)
5{
6	struct iovec iovs[2] = {
7		{ .iov_base = f->wbase, .iov_len = f->wpos-f->wbase },
8		{ .iov_base = (void *)buf, .iov_len = len }
9	};
10	struct iovec *iov = iovs;
11	size_t rem = iov[0].iov_len + iov[1].iov_len;
12	int iovcnt = 2;
13	ssize_t cnt;
14	for (;;) {
15		cnt = syscall(SYS_writev, f->fd, iov, iovcnt);
16		if (cnt == rem) {
17			f->wend = f->buf + f->buf_size;
18			f->wpos = f->wbase = f->buf;
19			return len;
20		}
21		if (cnt < 0) {
22			f->wpos = f->wbase = f->wend = 0;
23			f->flags |= F_ERR;
24			return iovcnt == 2 ? 0 : len-iov[0].iov_len;
25		}
26		rem -= cnt;
27		if (cnt > iov[0].iov_len) {
28			cnt -= iov[0].iov_len;
29			iov++; iovcnt--;
30		}
31		iov[0].iov_base = (char *)iov[0].iov_base + cnt;
32		iov[0].iov_len -= cnt;
33	}
34}
35