net: caif: use strlcpy() instead of strncpy()

gcc-8 reports

net/caif/caif_dev.c: In function 'caif_enroll_dev':
./include/linux/string.h:245:9: warning: '__builtin_strncpy' output may
be truncated copying 15 bytes from a string of length 15
[-Wstringop-truncation]

net/caif/cfctrl.c: In function 'cfctrl_linkup_request':
./include/linux/string.h:245:9: warning: '__builtin_strncpy' output may
be truncated copying 15 bytes from a string of length 15
[-Wstringop-truncation]

net/caif/cfcnfg.c: In function 'caif_connect_client':
./include/linux/string.h:245:9: warning: '__builtin_strncpy' output may
be truncated copying 15 bytes from a string of length 15
[-Wstringop-truncation]

The compiler require that the input param 'len' of strncpy() should be
greater than the length of the src string, so that '\0' is copied as
well. We can just use strlcpy() to avoid this warning.

Signed-off-by: Xiongfeng Wang <xiongfeng.wang@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/caif/caif_dev.c

@@ -334,9 +334,8 @@ void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
 	mutex_lock(&caifdevs->lock);
 	list_add_rcu(&caifd->list, &caifdevs->list);
 
-	strncpy(caifd->layer.name, dev->name,
-		sizeof(caifd->layer.name) - 1);
-	caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
+	strlcpy(caifd->layer.name, dev->name,
+		sizeof(caifd->layer.name));
 	caifd->layer.transmit = transmit;
 	cfcnfg_add_phy_layer(cfg,
 				dev,

net/caif/cfcnfg.c

@@ -268,17 +268,15 @@ static int caif_connect_req_to_link_param(struct cfcnfg *cnfg,
 	case CAIFPROTO_RFM:
 		l->linktype = CFCTRL_SRV_RFM;
 		l->u.datagram.connid = s->sockaddr.u.rfm.connection_id;
-		strncpy(l->u.rfm.volume, s->sockaddr.u.rfm.volume,
-			sizeof(l->u.rfm.volume)-1);
-		l->u.rfm.volume[sizeof(l->u.rfm.volume)-1] = 0;
+		strlcpy(l->u.rfm.volume, s->sockaddr.u.rfm.volume,
+			sizeof(l->u.rfm.volume));
 		break;
 	case CAIFPROTO_UTIL:
 		l->linktype = CFCTRL_SRV_UTIL;
 		l->endpoint = 0x00;
 		l->chtype = 0x00;
-		strncpy(l->u.utility.name, s->sockaddr.u.util.service,
-			sizeof(l->u.utility.name)-1);
-		l->u.utility.name[sizeof(l->u.utility.name)-1] = 0;
+		strlcpy(l->u.utility.name, s->sockaddr.u.util.service,
+			sizeof(l->u.utility.name));
 		caif_assert(sizeof(l->u.utility.name) > 10);
 		l->u.utility.paramlen = s->param.size;
 		if (l->u.utility.paramlen > sizeof(l->u.utility.params))

net/caif/cfctrl.c

@@ -258,8 +258,8 @@ int cfctrl_linkup_request(struct cflayer *layer,
 		tmp16 = cpu_to_le16(param->u.utility.fifosize_bufs);
 		cfpkt_add_body(pkt, &tmp16, 2);
 		memset(utility_name, 0, sizeof(utility_name));
-		strncpy(utility_name, param->u.utility.name,
-			UTILITY_NAME_LENGTH - 1);
+		strlcpy(utility_name, param->u.utility.name,
+			UTILITY_NAME_LENGTH);
 		cfpkt_add_body(pkt, utility_name, UTILITY_NAME_LENGTH);
 		tmp8 = param->u.utility.paramlen;
 		cfpkt_add_body(pkt, &tmp8, 1);