1 #include <u.h>
2 #include <libc.h>
3 #include <fcall.h>
4 #include <thread.h>
5 
6 int
7 threadread9pmsg(int fd, void *abuf, uint n)
8 {
9 	int m, len;
10 	uchar *buf;
11 
12 	buf = abuf;
13 
14 	/* read count */
15 	m = threadreadn(fd, buf, BIT32SZ);
16 	if(m != BIT32SZ){
17 		if(m < 0)
18 			return -1;
19 		return 0;
20 	}
21 
22 	len = GBIT32(buf);
23 	if(len <= BIT32SZ || len > n){
24 		werrstr("bad length in 9P2000 message header");
25 		return -1;
26 	}
27 	len -= BIT32SZ;
28 	m = threadreadn(fd, buf+BIT32SZ, len);
29 	if(m < len)
30 		return 0;
31 	return BIT32SZ+m;
32 }