basic04-pinning-maps: Implementation of unloading program and unpinning map

Signed-off-by: Xun Gu <xugu@redhat.com>

Author: Xun Gu

basic-solutions/xdp_loader.c

@@ -84,7 +84,7 @@ int pin_maps_in_bpf_object(struct bpf_object *bpf_obj, struct config *cfg)
 	}
 
 	/* Existing/previous XDP prog might not have cleaned up */
-	if (access(map_filename, F_OK ) != -1 ) {
+	if (access(map_filename, F_OK) != -1 ) {
 		if (verbose)
 			printf(" - Unpinning (remove) prev maps in %s/\n",
 			       cfg->pin_dir);

basic04-pinning-maps/xdp_loader.c

@@ -134,8 +134,41 @@ int main(int argc, char **argv)
 		return EXIT_FAIL_OPTION;
 	}
 	if (cfg.do_unload) {
-		/* TODO: Miss unpin of maps on unload */
-		/* return xdp_link_detach(cfg.ifindex, cfg.xdp_flags, 0); */
+		/* unpin the maps */
+		char map_filename[PATH_MAX];
+		int len;
+
+		len = snprintf(map_filename, PATH_MAX, "%s/%s/%s", pin_basedir,
+			       cfg.ifname, map_name);
+		if (len < 0) {
+			fprintf(stderr, "ERR: creating map filename for unload\n");
+			return EXIT_FAIL_OPTION;
+		}
+
+		/* Check if the map file exists and unpin it */
+		if (access(map_filename, F_OK) == 0) {
+			if (verbose)
+				printf(" - Unpinning map %s\n", map_filename);
+
+			/* Use unlink to remove the pinned map file */
+			err = unlink(map_filename);
+			if (err) {
+				fprintf(stderr, "ERR: Failed to unpin map %s: %s\n",
+					map_filename, strerror(errno));
+			}
+		}
+
+		/* unload the program */
+		err = do_unload(&cfg);
+		if (err) {
+			char errmsg[1024];
+			libxdp_strerror(err, errmsg, sizeof(errmsg));
+			fprintf(stderr, "Couldn't unload XDP program: %s\n", errmsg);
+			return err;
+		}
+
+		printf("Success: Unloaded XDP program\n");
+		return EXIT_OK;
 	}
 
 	program = load_bpf_and_xdp_attach(&cfg);