tools/libs/stat: use memcpy instead of strncpy in getBridge

Use memcpy in getBridge to prevent gcc warnings about truncated
strings. We know that we might truncate it, so the gcc warning
here is wrong.
Revert previous change changing buffer sizes as bigger buffers
are not needed.

Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Acked-by: Wei Liu <wl@xen.org>

tools/libs/stat/xenstat_linux.c

@@ -29,6 +29,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <regex.h>
+#include <xen-tools/libs.h>
 
 #include "xenstat_priv.h"
 
@@ -78,8 +79,14 @@ static void getBridge(char *excludeName, char *result, size_t resultLen)
 				sprintf(tmp, "/sys/class/net/%s/bridge", de->d_name);
 
 				if (access(tmp, F_OK) == 0) {
-					strncpy(result, de->d_name, resultLen);
-					result[resultLen - 1] = 0;
+					/*
+					 * Do not use strncpy to prevent compiler warning with
+					 * gcc >= 10.0
+					 * If de->d_name is longer then resultLen we truncate it
+					 */
+					memset(result, 0, resultLen);
+					memcpy(result, de->d_name, MIN(strnlen(de->d_name,
+									NAME_MAX),resultLen - 1));
 				}
 		}
 	}
@@ -264,7 +271,7 @@ int xenstat_collect_networks(xenstat_node * node)
 {
 	/* Helper variables for parseNetDevLine() function defined above */
 	int i;
-	char line[512] = { 0 }, iface[16] = { 0 }, devBridge[256] = { 0 }, devNoBridge[257] = { 0 };
+	char line[512] = { 0 }, iface[16] = { 0 }, devBridge[16] = { 0 }, devNoBridge[17] = { 0 };
 	unsigned long long rxBytes, rxPackets, rxErrs, rxDrops, txBytes, txPackets, txErrs, txDrops;
 
 	struct priv_data *priv = get_priv_data(node->handle);