drivers can_native_linux: Set socket to be closed on exec

If the process does an exec() (or fork, or..) all descriptors are kept
open by default, unless O_CLOEXEC is set for them.
(This default behaviour is usefull for stdin/out/err so that new process
is kept connected to them, but it is very rare for it to be usefull for
any other descriptor)

In general this leads to descriptors being kept open unnecessarily,
which either will block other process from using them (for example
if the child survives the parent but it does something else while keeping
a port open).
Or for a "leak" which unnecessarily uses descriptors and memory in the
child process.

Let's ensure we do not leak it for this component as we do not need it.

Signed-off-by: Alberto Escolar Piedras <[email protected]>

Author: aescolar

drivers/can/can_native_linux_adapt.c

@@ -47,7 +47,7 @@ int linux_socketcan_iface_open(const char *if_name)
 	struct ifreq ifr;
 	int fd, opt, ret = -EINVAL;
 
-	fd = socket(PF_CAN, SOCK_RAW, CAN_RAW);
+	fd = socket(PF_CAN, SOCK_RAW | SOCK_CLOEXEC, CAN_RAW);
 	if (fd < 0) {
 		return -errno;
 	}