make error handling in 9p service loops consistent

when we get eof, stop the loop immidiately and do not
rely on the read to eventually return an error.

when convM2S() fails to decode the message, error out
and stop the loop. there is no point in continuing.

1 files changed, 9 insertions, 9 deletions

diff --git a/sys/src/cmd/cwfs/srv.c b/sys/src/cmd/cwfs/srv.c
index b3f5d7b65..e022b9fbf 100644
--- a/sys/src/cmd/cwfs/srv.c
+++ b/sys/src/cmd/cwfs/srv.c
@@ -104,8 +104,9 @@ srvi(void *aux)
 	Msgbuf *mb, *ms;
 	uchar *b, *p, *e;
 	int n, m;
-	char buf[ERRMAX];
+	char err[ERRMAX];
 
+	err[0] = 0;
 	chan = aux;
 	srv = chan->pdata;
 
@@ -116,13 +117,13 @@ srvi(void *aux)
 	e = b + mb->count;
 
 Read:
-	while((n = read(srv->fd, p, e - p)) >= 0){
+	while((n = read(srv->fd, p, e - p)) > 0){
 		p += n;
 		while((p - b) >= BIT32SZ){
 			m = GBIT32(b);
 			if((m < BIT32SZ) || (m > mb->count)){
-				werrstr("bad length in 9P2000 message header");
-				goto Error;
+				strcpy(err, "bad length in 9P2000 message header");
+				goto Hangup;
 			}
 			if((n = (p - b) - m) < 0){
 				e = b + m;
@@ -149,12 +150,11 @@ Read:
 		e = b + mb->count;
 	}
 
-Error:
-	rerrstr(buf, sizeof(buf));
-	if(strstr(buf, "interrupt"))
-		goto Read;
+	if(n < 0)
+		errstr(err, sizeof(err));
 
-	chanhangup(chan, buf);
+Hangup:
+	chanhangup(chan, err);
 	srvput(srv);
 
 	mbfree(mb);