[PATCH 1/2] examples/send-zerocopy: fix -Wstringop-truncation on ifr.ifr_name

[Yang Xiuwei <yangxiuwei@kylinos.cn>]

strncpy(ifr.ifr_name, cfg_ifname, sizeof(ifr.ifr_name)) triggers
-Wstringop-truncation because the bound equals the destination size,
so the compiler assumes the result may not be null-terminated. Use
sizeof(ifr.ifr_name) - 1 as the bound so at most 15 bytes are copied.

Fixes: 3e4f05342662 ("examples/send-zerocopy: use strncpy() to copy interface name")
Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
---
 examples/send-zerocopy.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/send-zerocopy.c b/examples/send-zerocopy.c
index f0248d20..b2821af6 100644
--- a/examples/send-zerocopy.c
+++ b/examples/send-zerocopy.c
@@ -353,7 +353,7 @@ static void do_tx(struct thread_data *td, int domain, int type, int protocol)
 		struct ifreq ifr;
 
 		memset(&ifr, 0, sizeof(ifr));
-		strncpy(ifr.ifr_name, cfg_ifname, sizeof(ifr.ifr_name));
+		strncpy(ifr.ifr_name, cfg_ifname, sizeof(ifr.ifr_name) - 1);
 
 		if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr)) < 0)
 			t_error(1, errno, "Binding to device failed\n");
-- 
2.25.1