1#include "stdio_impl.h"
 2#include <sys/uio.h>
 3
 4size_t __stdio_read(FILE *f, unsigned char *buf, size_t len)
 5{
 6	struct iovec iov[2] = {
 7		{ .iov_base = buf, .iov_len = len - !!f->buf_size },
 8		{ .iov_base = f->buf, .iov_len = f->buf_size }
 9	};
10	ssize_t cnt;
11
12	cnt = iov[0].iov_len ? syscall(SYS_readv, f->fd, iov, 2)
13		: syscall(SYS_read, f->fd, iov[1].iov_base, iov[1].iov_len);
14	if (cnt <= 0) {
15		f->flags |= cnt ? F_ERR : F_EOF;
16		return 0;
17	}
18	if (cnt <= iov[0].iov_len) return cnt;
19	cnt -= iov[0].iov_len;
20	f->rpos = f->buf;
21	f->rend = f->buf + cnt;
22	if (f->buf_size) buf[len-1] = *f->rpos++;
23	return len;
24}