diff --git a/src/locking/lock_driver_sanlock.c b/src/locking/lock_driver_sanlock.c
index 345cf0a772..3f3a587541 100644
--- a/src/locking/lock_driver_sanlock.c
+++ b/src/locking/lock_driver_sanlock.c
@@ -1004,7 +1004,8 @@ static int virLockManagerSanlockAcquire(virLockManagerPtr lock,
     /* sanlock doesn't use owner_name for anything, so it's safe to take just
      * the first SANLK_NAME_LEN - 1 characters from vm_name */
     ignore_value(virStrncpy(opt->owner_name, priv->vm_name,
-                            SANLK_NAME_LEN - 1, SANLK_NAME_LEN));
+                            MIN(strlen(priv->vm_name), SANLK_NAME_LEN - 1),
+                            SANLK_NAME_LEN));
 
     if (state && STRNEQ(state, "")) {
         if ((rv = sanlock_state_to_args((char *)state,
diff --git a/src/xenapi/xenapi_driver.c b/src/xenapi/xenapi_driver.c
index 42b305d316..f4375c5874 100644
--- a/src/xenapi/xenapi_driver.c
+++ b/src/xenapi/xenapi_driver.c
@@ -430,7 +430,9 @@ xenapiNodeGetInfo(virConnectPtr conn, virNodeInfoPtr info)
     if (xen_host_cpu_get_all(session, &host_cpu_set)) {
         host_cpu = host_cpu_set->contents[0];
         xen_host_cpu_get_modelname(session, &modelname, host_cpu);
-        if (!virStrncpy(info->model, modelname, LIBVIRT_MODELNAME_LEN - 1, LIBVIRT_MODELNAME_LEN)) {
+        if (!virStrncpy(info->model, modelname,
+                        MIN(strlen(modelname), LIBVIRT_MODELNAME_LEN - 1),
+                        LIBVIRT_MODELNAME_LEN)) {
             virReportOOMError();
             xen_host_cpu_set_free(host_cpu_set);
             VIR_FREE(modelname);
diff --git a/src/xenconfig/xen_common.c b/src/xenconfig/xen_common.c
index 4a94127da1..815ccd030e 100644
--- a/src/xenconfig/xen_common.c
+++ b/src/xenconfig/xen_common.c
@@ -879,7 +879,7 @@ xenParseVif(char *entry, const char *vif_typename)
         data++;
 
         if (STRPREFIX(key, "mac=")) {
-            int len = nextkey ? (nextkey - data) : sizeof(mac) - 1;
+            int len = nextkey ? (nextkey - data) : strlen(data);
             if (virStrncpy(mac, data, len, sizeof(mac)) == NULL) {
                 virReportError(VIR_ERR_INTERNAL_ERROR,
                                _("MAC address %s too big for destination"),
@@ -887,7 +887,7 @@ xenParseVif(char *entry, const char *vif_typename)
                 return NULL;
             }
         } else if (STRPREFIX(key, "bridge=")) {
-            int len = nextkey ? (nextkey - data) : sizeof(bridge) - 1;
+            int len = nextkey ? (nextkey - data) : strlen(data);
             if (virStrncpy(bridge, data, len, sizeof(bridge)) == NULL) {
                 virReportError(VIR_ERR_INTERNAL_ERROR,
                                _("Bridge %s too big for destination"),
@@ -900,7 +900,7 @@ xenParseVif(char *entry, const char *vif_typename)
             if (VIR_STRNDUP(script, data, len) < 0)
                 return NULL;
         } else if (STRPREFIX(key, "model=")) {
-            int len = nextkey ? (nextkey - data) : sizeof(model) - 1;
+            int len = nextkey ? (nextkey - data) : strlen(data);
             if (virStrncpy(model, data, len, sizeof(model)) == NULL) {
                 virReportError(VIR_ERR_INTERNAL_ERROR,
                                _("Model %s too big for destination"),
@@ -908,7 +908,7 @@ xenParseVif(char *entry, const char *vif_typename)
                 return NULL;
             }
         } else if (STRPREFIX(key, "type=")) {
-            int len = nextkey ? (nextkey - data) : sizeof(type) - 1;
+            int len = nextkey ? (nextkey - data) : strlen(data);
             if (virStrncpy(type, data, len, sizeof(type)) == NULL) {
                 virReportError(VIR_ERR_INTERNAL_ERROR,
                                _("Type %s too big for destination"),
@@ -916,7 +916,7 @@ xenParseVif(char *entry, const char *vif_typename)
                 return NULL;
             }
         } else if (STRPREFIX(key, "vifname=")) {
-            int len = nextkey ? (nextkey - data) : sizeof(vifname) - 1;
+            int len = nextkey ? (nextkey - data) : strlen(data);
             if (virStrncpy(vifname, data, len, sizeof(vifname)) == NULL) {
                 virReportError(VIR_ERR_INTERNAL_ERROR,
                                _("Vifname %s too big for destination"),
@@ -924,14 +924,14 @@ xenParseVif(char *entry, const char *vif_typename)
                 return NULL;
             }
         } else if (STRPREFIX(key, "ip=")) {
-            int len = nextkey ? (nextkey - data) : sizeof(ip) - 1;
+            int len = nextkey ? (nextkey - data) : strlen(data);
             if (virStrncpy(ip, data, len, sizeof(ip)) == NULL) {
                 virReportError(VIR_ERR_INTERNAL_ERROR,
                                _("IP %s too big for destination"), data);
                 return NULL;
             }
         } else if (STRPREFIX(key, "rate=")) {
-            int len = nextkey ? (nextkey - data) : sizeof(rate) - 1;
+            int len = nextkey ? (nextkey - data) : strlen(data);
             if (virStrncpy(rate, data, len, sizeof(rate)) == NULL) {
                 virReportError(VIR_ERR_INTERNAL_ERROR,
                                _("rate %s too big for destination"), data);
diff --git a/src/xenconfig/xen_xl.c b/src/xenconfig/xen_xl.c
index 807fe621d6..bc3191ad5e 100644
--- a/src/xenconfig/xen_xl.c
+++ b/src/xenconfig/xen_xl.c
@@ -899,7 +899,7 @@ xenParseXLUSBController(virConfPtr conf, virDomainDefPtr def)
                 data++;
 
                 if (STRPREFIX(key, "type=")) {
-                    int len = nextkey ? (nextkey - data) : sizeof(type) - 1;
+                    int len = nextkey ? (nextkey - data) : strlen(data);
                     if (virStrncpy(type, data, len, sizeof(type)) == NULL) {
                         virReportError(VIR_ERR_INTERNAL_ERROR,
                                        _("type %s invalid"),
@@ -907,7 +907,7 @@ xenParseXLUSBController(virConfPtr conf, virDomainDefPtr def)
                         goto skipusbctrl;
                     }
                 } else if (STRPREFIX(key, "version=")) {
-                    int len = nextkey ? (nextkey - data) : sizeof(version) - 1;
+                    int len = nextkey ? (nextkey - data) : strlen(data);
                     if (virStrncpy(version, data, len, sizeof(version)) == NULL) {
                         virReportError(VIR_ERR_INTERNAL_ERROR,
                                        _("version %s invalid"),
@@ -917,7 +917,7 @@ xenParseXLUSBController(virConfPtr conf, virDomainDefPtr def)
                     if (virStrToLong_i(version, NULL, 16, &usbctrl_version) < 0)
                         goto skipusbctrl;
                 } else if (STRPREFIX(key, "ports=")) {
-                    int len = nextkey ? (nextkey - data) : sizeof(ports) - 1;
+                    int len = nextkey ? (nextkey - data) : strlen(data);
                     if (virStrncpy(ports, data, len, sizeof(ports)) == NULL) {
                         virReportError(VIR_ERR_INTERNAL_ERROR,
                                        _("version %s invalid"),
@@ -1001,7 +1001,7 @@ xenParseXLUSB(virConfPtr conf, virDomainDefPtr def)
                 data++;
 
                 if (STRPREFIX(key, "hostbus=")) {
-                    int len = nextkey ? (nextkey - data) : sizeof(bus) - 1;
+                    int len = nextkey ? (nextkey - data) : strlen(data);
                     if (virStrncpy(bus, data, len, sizeof(bus)) == NULL) {
                         virReportError(VIR_ERR_INTERNAL_ERROR,
                                        _("bus %s too big for destination"),
@@ -1009,7 +1009,7 @@ xenParseXLUSB(virConfPtr conf, virDomainDefPtr def)
                         goto skipusb;
                     }
                 } else if (STRPREFIX(key, "hostaddr=")) {
-                    int len = nextkey ? (nextkey - data) : sizeof(device) - 1;
+                    int len = nextkey ? (nextkey - data) : strlen(data);
                     if (virStrncpy(device, data, len, sizeof(device)) == NULL) {
                         virReportError(VIR_ERR_INTERNAL_ERROR,
                                        _("device %s too big for destination"),
@@ -1077,7 +1077,7 @@ xenParseXLChannel(virConfPtr conf, virDomainDefPtr def)
                 data++;
 
                 if (STRPREFIX(key, "connection=")) {
-                    int len = nextkey ? (nextkey - data) : sizeof(type) - 1;
+                    int len = nextkey ? (nextkey - data) : strlen(data);
                     if (virStrncpy(type, data, len, sizeof(type)) == NULL) {
                         virReportError(VIR_ERR_INTERNAL_ERROR,
                                        _("connection %s too big"), data);