tools, bpftool: Add missing close before bpftool net attach exit

progfd is created by prog_parse_fd() in do_attach() and before the latter
returns in case of success, the file descriptor should be closed.

Fixes: 04949cc ("tools: bpftool: add net attach command to attach XDP on interface")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201113115152.53178-1-wanghai38@huawei.com

Author: Wang Hai

tools/bpf/bpftool/net.c

@@ -578,35 +578,35 @@ static int do_attach(int argc, char **argv)
 
 	ifindex = net_parse_dev(&argc, &argv);
 	if (ifindex < 1) {
-		close(progfd);
-		return -EINVAL;
+		err = -EINVAL;
+		goto cleanup;
 	}
 
 	if (argc) {
 		if (is_prefix(*argv, "overwrite")) {
 			overwrite = true;
 		} else {
 			p_err("expected 'overwrite', got: '%s'?", *argv);
-			close(progfd);
-			return -EINVAL;
+			err = -EINVAL;
+			goto cleanup;
 		}
 	}
 
 	/* attach xdp prog */
 	if (is_prefix("xdp", attach_type_strings[attach_type]))
 		err = do_attach_detach_xdp(progfd, attach_type, ifindex,
 					   overwrite);
-
-	if (err < 0) {
+	if (err) {
 		p_err("interface %s attach failed: %s",
 		      attach_type_strings[attach_type], strerror(-err));
-		return err;
+		goto cleanup;
 	}
 
 	if (json_output)
 		jsonw_null(json_wtr);
-
-	return 0;
+cleanup:
+	close(progfd);
+	return err;
 }
 
 static int do_detach(int argc, char **argv)