tap, tcp, util: Add some missing SOCK_CLOEXEC flags

I have no idea why, but these are reported by clang-tidy (19.2.1) on
Alpine (x86) only:

/home/sbrivio/passt/tap.c:1139:38: error: 'socket' should use SOCK_CLOEXEC where possible [android-cloexec-socket,-warnings-as-errors]
 1139 |         int fd = socket(AF_UNIX, SOCK_STREAM, 0);
      |                                             ^
      |                                              | SOCK_CLOEXEC
/home/sbrivio/passt/tap.c:1158:51: error: 'socket' should use SOCK_CLOEXEC where possible [android-cloexec-socket,-warnings-as-errors]
 1158 |                 ex = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0);
      |                                                                 ^
      |                                                                  | SOCK_CLOEXEC
/home/sbrivio/passt/tcp.c:1413:44: error: 'socket' should use SOCK_CLOEXEC where possible [android-cloexec-socket,-warnings-as-errors]
 1413 |         s = socket(af, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
      |                                                   ^
      |                                                    | SOCK_CLOEXEC
/home/sbrivio/passt/util.c:188:38: error: 'socket' should use SOCK_CLOEXEC where possible [android-cloexec-socket,-warnings-as-errors]
  188 |         if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
      |                                             ^
      |                                              | SOCK_CLOEXEC

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

3 files changed, 6 insertions, 4 deletions

diff --git a/tap.c b/tap.c
index a3ba958..14d9b3d 100644
--- a/tap.c
+++ b/tap.c
@@ -1136,7 +1136,7 @@ void tap_handler_pasta(struct ctx *c, uint32_t events,
  */
 int tap_sock_unix_open(char *sock_path)
 {
-	int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+	int fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
 	struct sockaddr_un addr = {
 		.sun_family = AF_UNIX,
 	};
@@ -1155,7 +1155,8 @@ int tap_sock_unix_open(char *sock_path)
 					UNIX_SOCK_PATH, i))
 			die_perror("Can't build UNIX domain socket path");
 
-		ex = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0);
+		ex = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC,
+			    0);
 		if (ex < 0)
 			die_perror("Failed to check for UNIX domain conflicts");
 
diff --git a/tcp.c b/tcp.c
index a3d48fa..6a98dfa 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1410,7 +1410,7 @@ static int tcp_conn_new_sock(const struct ctx *c, sa_family_t af)
 {
 	int s;
 
-	s = socket(af, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
+	s = socket(af, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, IPPROTO_TCP);
 
 	if (s > FD_REF_MAX) {
 		close(s);
diff --git a/util.c b/util.c
index dddef93..3448f30 100644
--- a/util.c
+++ b/util.c
@@ -183,7 +183,8 @@ void sock_probe_mem(struct ctx *c)
 	int v = INT_MAX / 2, s;
 	socklen_t sl;
 
-	if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
+	s = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+	if (s < 0) {
 		c->low_wmem = c->low_rmem = 1;
 		return;
 	}