[PATCH mptcp-next v14 02/12] selftests: mptcp: sockopt: use exact length in connect_one_server

From: Geliang Tang <[email protected]>

Use the exact remaining length ('len - total') when reading the echoed data
from the socket, instead of the full buffer size.

This silences a false positive -Wstringop-overflow warning from GCC, as the
compiler can now prove that the destination buffer is large enough for the
specified read size.

connect_one_server() passes per-chunk 'ret' to do_getsockopts() instead of
cumulative 'total', causing mismatches when the echo is fragmented. Fix by
passing 'total' to match the semantics used in process_one_client().

Signed-off-by: Geliang Tang <[email protected]>
---
 tools/testing/selftests/net/mptcp/mptcp_sockopt.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
index 6c3d896d4a1b..469384823dc6 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_sockopt.c
@@ -609,7 +609,7 @@ static void connect_one_server(int fd, int pipefd)
 
 	total = 0;
 	do {
-		ret = read(fd, buf2 + total, sizeof(buf2) - total);
+		ret = read(fd, buf2 + total, len - total);
 		if (ret < 0)
 			die_perror("read");
 		if (ret == 0) {
@@ -629,7 +629,7 @@ static void connect_one_server(int fd, int pipefd)
 	if (s.tcpi_rcv_delta)
 		assert(s.tcpi_rcv_delta <= total);
 
-	do_getsockopts(&s, fd, ret, ret);
+	do_getsockopts(&s, fd, total, total);
 
 	if (eof)
 		total += 1; /* sequence advances due to FIN */
-- 
2.53.0