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}