mqueue, ubx-mq: fix issue caused by strictler cleanup

Using a strictler block cleanup policy caused the mqueues created by
ubx-mq tool to be properly destructed, but in their cleanup they
called mq_unlink which removed the queue. This adds a mqueue config
`unlink` to defined whether the queue shall be removed or not (default
yes).

In addition, the ubx.node_cleanup is set as the default gc method for
node instead of ubx.node_rm. This leaves the logging intact, which is
desirable for the same reasons as above. ubx.node_rm can still be
called explicitly (i.e. as done by blockdiagram:pulldown) when the
main node is being destructed.

Signed-off-by: Markus Klotzbuecher <mk@mkio.de>

lua/ubx.lua

@@ -309,7 +309,7 @@ end
 -- @param attrs node attributes
 -- @return ubx_node_t
 function M.node_create(name, params)
-   local nd = ffi.gc(ffi.new("ubx_node_t"), ubx.ubx_node_rm)
+   local nd = ffi.gc(ffi.new("ubx_node_t"), ubx.ubx_node_cleanup)
    params = params or {}
    local attrs=0
    if params.mlockall then attrs = bit.bor(attrs, ffi.C.ND_MLOCK_ALL) end

std_blocks/mqueue/mqueue.c

@@ -22,6 +22,7 @@ ubx_proto_config_t mqueue_config[] = {
 	{ .name = "data_len", .type_name = "long", .max = 1, .doc = "array length (multiplier) of data (default: 1)" },
 	{ .name = "buffer_len", .type_name = "long", .min = 1, .max = 1, .doc = "max number of data elements the buffer shall hold" },
 	{ .name = "blocking", .type_name = "uint32_t", .min = 0, .max = 1, .doc = "enable blocking mode (def: 0)" },
+	{ .name = "unlink", .type_name = "uint32_t", .min = 0, .max = 1, .doc = "call mq_unlink in cleanup (def: 1 (yes)" },
 	{ 0 }
 };
 
@@ -35,6 +36,7 @@ struct mqueue_info {
 	const ubx_type_t *type;		/* type of contained elements */
 	long data_len;			/* buffer size of each element */
 	long buffer_len;		/* number of elements */
+	uint32_t unlink;
 
 	unsigned long cnt_send_err;
 	unsigned long cnt_recv_err;
@@ -112,6 +114,11 @@ int mqueue_init(ubx_block_t *i)
 		goto out_free_info;
 	}
 
+	/* unlink */
+	len = cfg_getptr_uint32(i, "unlink", &val);
+	assert(len >= 0);
+	inf->unlink = (len>0) ? *val : 1;
+
 	/* configure max message size */
 	mqa.mq_msgsize = inf->data_len * inf->type->size;
 
@@ -169,10 +176,13 @@ void mqueue_cleanup(ubx_block_t *i)
 	if (mq_close(inf->mqd) != 0)
 		ubx_err(i, "mq_close %s failed: %s", inf->mq_name, strerror(errno));
 
-	ret = mq_unlink(inf->mq_name);
+	if (inf->unlink) {
+		ubx_info(i, "%s: removing mq %s", __func__, inf->mq_name);
+		ret = mq_unlink(inf->mq_name);
 
-	if (ret < 0 && errno != ENOENT)
-		ubx_err(i, "mq_unlink %s failed: %s", inf->mq_name, strerror(errno));
+		if (ret < 0 && errno != ENOENT)
+			ubx_err(i, "mq_unlink %s failed: %s", inf->mq_name, strerror(errno));
+	}
 
 	free(inf);
 }

tools/ubx-mq

@@ -85,6 +85,7 @@ local function read(mqtab, preloads)
 		       type_name = ubx.safe_tostr(typ.name),
 		       data_len = mqtab.data_len,
 		       buffer_len = 32,
+		       unlink=0,
 		       blocking = 1 } )
 
    local mq = nd:b("mq")