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}