1#ifdef __wasilibc_unmodified_upstream // WASI has no syscall
 2#else
 3#include <unistd.h>
 4#endif
 5#include "stdio_impl.h"
 6#include <sys/uio.h>
 7
 8size_t __stdio_read(FILE *f, unsigned char *buf, size_t len)
 9{
10	struct iovec iov[2] = {
11		{ .iov_base = buf, .iov_len = len - !!f->buf_size },
12		{ .iov_base = f->buf, .iov_len = f->buf_size }
13	};
14	ssize_t cnt;
15
16#ifdef __wasilibc_unmodified_upstream // WASI has no syscall
17	cnt = iov[0].iov_len ? syscall(SYS_readv, f->fd, iov, 2)
18		: syscall(SYS_read, f->fd, iov[1].iov_base, iov[1].iov_len);
19#else
20	cnt = iov[0].iov_len ? readv(f->fd, iov, 2)
21		: read(f->fd, iov[1].iov_base, iov[1].iov_len);
22#endif
23	if (cnt <= 0) {
24		f->flags |= cnt ? F_ERR : F_EOF;
25		return 0;
26	}
27	if (cnt <= iov[0].iov_len) return cnt;
28	cnt -= iov[0].iov_len;
29	f->rpos = f->buf;
30	f->rend = f->buf + cnt;
31	if (f->buf_size) buf[len-1] = *f->rpos++;
32	return len;
33}