tests: blobmsg: add test case

* add a test for blobmsg_check_array() to test an array with a string in it

This test was added in conjunction with a change to blobmsg_check_array() to
get it to pass the length obtained from blob_len() rather than blobmsg_len().

Signed-off-by: Chris Nisbet <nischris@gmail.com>

tests/cram/test_blobmsg_check_array.t

@@ -0,0 +1,8 @@
+check that blobmsg_check_array() is producing expected results:
+
+  $ [ -n "$TEST_BIN_DIR" ] && export PATH="$TEST_BIN_DIR:$PATH"
+
+  $ test-blobmsg_check_array
+  Process array_a: entry 0
+  array_b contains string: 1
+  blobmsg_check_array() test passed

tests/test-blobmsg_check_array.c

@@ -0,0 +1,169 @@
+#include <stdio.h>
+
+#include "blobmsg.h"
+
+/*
+ * This test tests a blob of this form...
+ *
+	{
+		"array_a" : [
+			{
+				"array_b": [
+					"1"
+				]
+			}
+		]
+	}
+ *
+ */
+
+
+enum {
+	ARRAY_A = 0,
+	ARRAY_B = 0,
+};
+
+static char const array_a[] = "array_a";
+static char const array_b[] = "array_b";
+
+static const struct blobmsg_policy pol_a[] = {
+	[ARRAY_A] = {
+		.name = array_a,
+		.type = BLOBMSG_TYPE_ARRAY
+	}
+};
+
+static const struct blobmsg_policy pol_b[] = {
+	[ARRAY_B] = {
+		.name = array_b,
+		.type = BLOBMSG_TYPE_ARRAY
+	}
+};
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+static int
+check_table_a_entries(struct blob_attr *attr)
+{
+	struct blob_attr *cur;
+	size_t rem;
+	int entry_number = 0;
+
+	blobmsg_for_each_attr(cur, attr, rem) {
+		int failed = 0;
+
+		fprintf(stderr, "Process %s: entry %d\n", array_a, entry_number);
+
+		struct blob_attr *tb[ARRAY_SIZE(pol_b)];
+
+		if (blobmsg_parse(pol_b, ARRAY_SIZE(pol_b), tb,
+						  blobmsg_data(cur), blobmsg_data_len(cur)) != 0) {
+			fprintf(stderr, "Policy %s parse failed\n", array_b);
+			return -1;
+		}
+
+		if (tb[ARRAY_B] == NULL) {
+			fprintf(stderr, "%s not found\n", array_b);
+			return -1;
+		}
+
+		/*
+		 * This is the test that fails when blobmsg_check_array() passes the
+		 * length obtained by blob_len(attr).
+		 * It succeeds when blobmsg_check_array() uses blob_len(attr), which is
+		 * equivalent to the origianl code, pre the length check changes.
+		 */
+		if (blobmsg_check_array(tb[ARRAY_B], BLOBMSG_TYPE_STRING) < 0) {
+			fprintf(stderr, "Failed blobmsg_check_array() (STRING) on %s\n",
+						array_b);
+			failed = 1;
+		}
+
+		/*
+		 * Continue outputting the strings even though the test above might
+		 * have failed.
+		 * This will show that the array does actually contain the expected
+		 * string.
+		 */
+
+		struct blob_attr *cur2;
+		size_t rem2;
+
+		blobmsg_for_each_attr(cur2, tb[ARRAY_B], rem2) {
+			fprintf(stderr, "%s contains string: %s\n",
+							array_b, blobmsg_get_string(cur2));
+		}
+
+
+		entry_number++;
+
+		if (failed)
+			return -1;
+	}
+
+	return 0;
+}
+
+static int
+check_message(struct blob_buf *buf)
+{
+	struct blob_attr *tb[ARRAY_SIZE(pol_a)];
+
+	if (blobmsg_parse(pol_a, ARRAY_SIZE(pol_a), tb,
+					  blob_data(buf->head), blobmsg_data_len(buf->head)) != 0) {
+		fprintf(stderr, "Policy %s parse failed\n", array_a);
+		return -1;
+	}
+
+	if (tb[ARRAY_A] == NULL) {
+		fprintf(stderr, "%s not found\n", array_a);
+		return -1;
+	}
+
+	int const result = blobmsg_check_array(tb[ARRAY_A], BLOBMSG_TYPE_TABLE);
+
+	if (result < 0) {
+		fprintf(stderr, "Failed blobmsg_check_array() (TABLE) on %s (%d)\n",
+				array_a, result);
+		return -1;
+	}
+
+	return check_table_a_entries(tb[ARRAY_A]);
+}
+
+static void
+fill_message(struct blob_buf * const buf)
+{
+	void * const tbl_a = blobmsg_open_array(buf, "array_a");
+	void * const obj = blobmsg_open_table(buf, NULL);
+
+	void * const tbl_b = blobmsg_open_array(buf, "array_b");
+
+	blobmsg_add_string(buf, NULL, "1");
+
+	blobmsg_close_array(buf, tbl_b);
+
+	blobmsg_close_table(buf, obj);
+
+	blobmsg_close_array(buf, tbl_a);
+}
+
+int main(int argc, char **argv)
+{
+	int result;
+	static struct blob_buf buf;
+
+	blobmsg_buf_init(&buf);
+	fill_message(&buf);
+
+	result = check_message(&buf);
+	if (result == 0)
+		fprintf(stderr, "blobmsg_check_array() test passed\n");
+
+	if (buf.buf != NULL)
+		free(buf.buf);
+
+	return result ? EXIT_FAILURE : EXIT_SUCCESS;
+}