Cast the NULL argument of straconcat to unsigned char *.

straconcat reads the args with va_arg(ap, const unsigned char *),
and the NULL macro may have the wrong type (e.g. int).

Many places pass string literals of type char * to straconcat.  This
is in principle also a violation, but I'm ignoring it for now because
if it becomes a problem with some C implementation, then so will the
use of unsigned char * with printf "%s", which is so widespread in
ELinks that I'm not going to try fixing it now.

src/bfu/inphist.c

@@ -289,7 +289,8 @@ load_input_history(struct input_history *history, unsigned char *filename)
 
 	if (get_cmd_opt_bool("anonymous")) return 0;
 	if (elinks_home) {
-		history_file = straconcat(elinks_home, filename, NULL);
+		history_file = straconcat(elinks_home, filename,
+					  (unsigned char *) NULL);
 		if (!history_file) return 0;
 	}
 
@@ -327,7 +328,8 @@ save_input_history(struct input_history *history, unsigned char *filename)
 	    || get_cmd_opt_bool("anonymous"))
 		return 0;
 
-	history_file = straconcat(elinks_home, filename, NULL);
+	history_file = straconcat(elinks_home, filename,
+				  (unsigned char *) NULL);
 	if (!history_file) return -1;
 
 	ssi = secure_open(history_file);

src/bfu/listmenu.c

@@ -177,7 +177,7 @@ menu_labels(struct menu_item *items, unsigned char *base, unsigned char **lbls)
 	foreach_menu_item (item, items) {
 		bs = (item->flags & MENU_FULLNAME) ? (unsigned char *) ""
 						   : base;
-		bs = straconcat(bs, item->text, NULL);
+		bs = straconcat(bs, item->text, (unsigned char *) NULL);
 		if (!bs) continue;
 
 		if (item->func == do_select_submenu) {

src/bookmarks/backend/common.c

@@ -57,7 +57,8 @@ bookmarks_read(void)
 	file_name = backend->filename(0);
 	if (!file_name) return;
 	if (elinks_home) {
-		file_name = straconcat(elinks_home, file_name, NULL);
+		file_name = straconcat(elinks_home, file_name,
+				       (unsigned char *) NULL);
 		if (!file_name) return;
 	}
 
@@ -91,7 +92,7 @@ bookmarks_write(struct list_head *bookmarks_list)
 	 * they would be just truncated to zero by secure_open()). */
 	file_name = backend->filename(1);
 	if (!file_name) return;
-	file_name = straconcat(elinks_home, file_name, NULL);
+	file_name = straconcat(elinks_home, file_name, (unsigned char *) NULL);
 	if (!file_name) return;
 
 	ssi = secure_open(file_name);

src/config/conf.c

@@ -500,13 +500,15 @@ load_config_file(unsigned char *prefix, unsigned char *name,
 {
 	unsigned char *config_str, *config_file;
 
-	config_file = straconcat(prefix, STRING_DIR_SEP, name, NULL);
+	config_file = straconcat(prefix, STRING_DIR_SEP, name,
+				 (unsigned char *) NULL);
 	if (!config_file) return 1;
 
 	config_str = read_config_file(config_file);
 	if (!config_str) {
 		mem_free(config_file);
-		config_file = straconcat(prefix, STRING_DIR_SEP, ".", name, NULL);
+		config_file = straconcat(prefix, STRING_DIR_SEP, ".", name,
+					 (unsigned char *) NULL);
 		if (!config_file) return 2;
 
 		config_str = read_config_file(config_file);
@@ -802,7 +804,7 @@ write_config_file(unsigned char *prefix, unsigned char *name,
 
 	if (name_has_slash && prefix_has_slash) name++;
 
-	config_file = straconcat(prefix, slash, name, NULL);
+	config_file = straconcat(prefix, slash, name, (unsigned char *) NULL);
 	if (!config_file) goto free_cfg_str;
 
 	ssi = secure_open(config_file);

src/config/dialogs.c

@@ -62,7 +62,8 @@ write_config_dialog(struct terminal *term, unsigned char *config_file,
 	strerr = secsave_strerror(secsave_error, term);
 
 	if (stdio_error > 0)
-		errmsg = straconcat(strerr, " (", strerror(stdio_error), ")", NULL);
+		errmsg = straconcat(strerr, " (", strerror(stdio_error), ")",
+				    (unsigned char *) NULL);
 
 	info_box(term, MSGBOX_FREE_TEXT,
 		 N_("Write config error"), ALIGN_CENTER,
@@ -121,7 +122,8 @@ get_option_text(struct listbox_item *item, struct terminal *term)
 
 	if (option->flags & OPT_TOUCHED)
 		return straconcat(_(desc, term),
-				  " (", _("modified", term), ")", NULL);
+				  " (", _("modified", term), ")",
+				  (unsigned char *) NULL);
 
 	return stracpy(_(desc, term));
 }
@@ -140,7 +142,8 @@ get_option_info(struct listbox_item *item, struct terminal *term)
 	type = _(option_types[option->type].name, term);
 	if (option->type == OPT_TREE) {
 		type = straconcat(type, " ",
-				_("(expand by pressing space)", term), NULL);
+				  _("(expand by pressing space)", term),
+				  (unsigned char *) NULL);
 	}
 
 	add_format_to_string(&info, "\n%s: %s", _("Type", term), type);
@@ -325,17 +328,19 @@ build_edit_dialog(struct terminal *term, struct session *ses,
 
 	name = straconcat(_("Name", term), ": ", option->name, "\n",
 			  _("Type", term), ": ",
-			  _(option_types[option->type].name, term), NULL);
+			  _(option_types[option->type].name, term),
+			  (unsigned char *) NULL);
 	desc = straconcat(_("Description", term), ": \n",
 			  _(option->desc ? option->desc
 				  	 : (unsigned char *) "N/A", term),
-			  NULL);
+			  (unsigned char *) NULL);
 	range = get_range_string(option);
 	if (range) {
 		if (*range) {
 			unsigned char *tmp;
 
-			tmp = straconcat(name, " ", range, NULL);
+			tmp = straconcat(name, " ", range,
+					 (unsigned char *) NULL);
 			if (tmp) {
 				mem_free(name);
 				name = tmp;

src/config/home.c

@@ -49,7 +49,8 @@ test_confdir(unsigned char *home, unsigned char *path,
 	if (!path || !*path) return NULL;
 
 	if (home && *home && !dir_sep(*path))
-		confdir = straconcat(home, STRING_DIR_SEP, path, NULL);
+		confdir = straconcat(home, STRING_DIR_SEP, path,
+				     (unsigned char *) NULL);
 	else
 		confdir = stracpy(path);
 

src/config/kbdbind.c

@@ -940,7 +940,7 @@ bind_act(unsigned char *keymap_str, const unsigned char *keystroke_str)
 		return NULL;
 
 	keybinding->flags |= KBDB_WATERMARK;
-	return straconcat("\"", action, "\"", NULL);
+	return straconcat("\"", action, "\"", (unsigned char *) NULL);
 }
 
 static void

src/cookies/cookies.c

@@ -720,7 +720,8 @@ load_cookies(void) {
 	time_t now;
 
 	if (elinks_home) {
-		cookfile = straconcat(elinks_home, cookfile, NULL);
+		cookfile = straconcat(elinks_home, cookfile,
+				      (unsigned char *) NULL);
 		if (!cookfile) return;
 	}
 
@@ -861,7 +862,8 @@ save_cookies(struct terminal *term) {
 		return;
 	}
 
-	cookfile = straconcat(elinks_home, COOKIES_FILENAME, NULL);
+	cookfile = straconcat(elinks_home, COOKIES_FILENAME,
+			      (unsigned char *) NULL);
 	if (!cookfile) {
 		CANNOT_SAVE_COOKIES(0, N_("Out of memory"));
 		return;

src/cookies/dialogs.c

@@ -354,7 +354,8 @@ build_edit_dialog(struct terminal *term, struct cookie *cookie)
 	ulongcat(secure, &length, cookie->secure, MAX_STR_LEN, 0);
 
 	dlg_server = cookie->server->host;
-	dlg_server = straconcat(_("Server", term), ": ", dlg_server, "\n", NULL);
+	dlg_server = straconcat(_("Server", term), ": ", dlg_server, "\n",
+				(unsigned char *) NULL);
 
 	if (!dlg_server) {
 		mem_free(dlg);

src/dialogs/status.c

@@ -152,7 +152,8 @@ get_current_link_info_and_title(struct session *ses,
 	if (link_title) {
 		assert(*link_title);
 
-		ret = straconcat(link_info, " - ", link_title, NULL);
+		ret = straconcat(link_info, " - ", link_title,
+				 (unsigned char *) NULL);
 		mem_free(link_info);
 		mem_free(link_title);
 	}
@@ -482,7 +483,8 @@ display_window_title(struct session *ses, struct terminal *term)
 	    && ses->doc_view->document->title[0])
 		doc_title = ses->doc_view->document->title;
 
-	title = doc_title ? straconcat(doc_title, " - ELinks", NULL)
+	title = doc_title ? straconcat(doc_title, " - ELinks",
+				       (unsigned char *) NULL)
 			  : stracpy("ELinks");
 	if (!title) return;
 

src/document/html/parser/link.c

@@ -232,7 +232,8 @@ html_img_do(unsigned char *a, unsigned char *object_src,
 
 		mem_free(usemap_attr);
 		if (!joined_urls) return;
-		map_url = straconcat("MAP@", joined_urls, NULL);
+		map_url = straconcat("MAP@", joined_urls,
+				     (unsigned char *) NULL);
 		mem_free(joined_urls);
 		if (!map_url) return;
 
@@ -308,7 +309,7 @@ html_img_do(unsigned char *a, unsigned char *object_src,
 		if (img_link_tag && (img_link_tag == 2 || add_brackets)) {
 			unsigned char *img_link_prefix = options->image_link.prefix;
 			unsigned char *img_link_suffix = options->image_link.suffix;
-			unsigned char *new_label = straconcat(img_link_prefix, label, img_link_suffix, NULL);
+			unsigned char *new_label = straconcat(img_link_prefix, label, img_link_suffix, (unsigned char *) NULL);
 
 			if (new_label) mem_free_set(&label, new_label);
 		}
@@ -327,7 +328,7 @@ html_img_do(unsigned char *a, unsigned char *object_src,
 				unsigned char *new_link;
 
 				html_stack_dup(html_context, ELEMENT_KILLABLE);
-				new_link = straconcat(format.link, "?0,0", NULL);
+				new_link = straconcat(format.link, "?0,0", (unsigned char *) NULL);
 				if (new_link)
 					mem_free_set(&format.link, new_link);
 			}

src/document/html/renderer.c

@@ -1409,7 +1409,8 @@ process_link(struct html_context *html_context, enum link_state link_state,
 		if (name) {
 			unsigned char *new_name;
 
-			new_name = straconcat(name, chars, NULL);
+			new_name = straconcat(name, chars,
+					      (unsigned char *) NULL);
 			if (new_name) {
 				mem_free(name);
 				link->data.name = new_name;

src/document/plain/renderer.c

@@ -123,7 +123,7 @@ check_link_word(struct document *document, unsigned char *uri, int length,
 	uri[length] = 0;
 
 	if (mailto && mailto > uri && mailto - uri < length - 1) {
-		where = straconcat("mailto:", uri, NULL);
+		where = straconcat("mailto:", uri, (unsigned char *) NULL);
 
 	} else if (parse_uri(&test, uri) == URI_ERRNO_OK
 		   && test.protocol != PROTOCOL_UNKNOWN

src/ecmascript/ecmascript.c

@@ -285,10 +285,10 @@ ecmascript_set_action(unsigned char **action, unsigned char *string)
 			struct uri *uri = get_uri(*action, URI_HTTP_REFERRER_HOST);
 
 			if (uri->protocol == PROTOCOL_FILE) {
-				mem_free_set(action, straconcat(struri(uri), string, NULL));
+				mem_free_set(action, straconcat(struri(uri), string, (unsigned char *) NULL));
 			}
 			else
-				mem_free_set(action, straconcat(struri(uri), string + 1, NULL));
+				mem_free_set(action, straconcat(struri(uri), string + 1, (unsigned char *) NULL));
 			done_uri(uri);
 			mem_free(string);
 		} else { /* relative uri */
@@ -296,7 +296,8 @@ ecmascript_set_action(unsigned char **action, unsigned char *string)
 			unsigned char *new_action;
 
 			if (last_slash) *(last_slash + 1) = '\0';
-			new_action = straconcat(*action, string, NULL);
+			new_action = straconcat(*action, string,
+						(unsigned char *) NULL);
 			mem_free_set(action, new_action);
 			mem_free(string);
 		}

src/formhist/formhist.c

@@ -99,7 +99,8 @@ load_formhist_from_file(void)
 
 	if (!elinks_home) return 0;
 
-	file = straconcat(elinks_home, FORMS_HISTORY_FILENAME, NULL);
+	file = straconcat(elinks_home, FORMS_HISTORY_FILENAME,
+			  (unsigned char *) NULL);
 	if (!file) return 0;
 
 	f = fopen(file, "rb");
@@ -222,7 +223,8 @@ save_formhist_to_file(void)
 	if (!elinks_home || get_cmd_opt_bool("anonymous"))
 		return 0;
 
-	file = straconcat(elinks_home, FORMS_HISTORY_FILENAME, NULL);
+	file = straconcat(elinks_home, FORMS_HISTORY_FILENAME,
+			  (unsigned char *) NULL);
 	if (!file) return 0;
 
 	ssi = secure_open(file);

src/globhist/globhist.c

@@ -341,7 +341,8 @@ read_global_history(void)
 		return;
 
 	if (elinks_home) {
-		file_name = straconcat(elinks_home, file_name, NULL);
+		file_name = straconcat(elinks_home, file_name,
+				       (unsigned char *) NULL);
 		if (!file_name) return;
 	}
 	f = fopen(file_name, "rb");
@@ -385,7 +386,8 @@ write_global_history(void)
 	    || get_cmd_opt_bool("anonymous"))
 		return;
 
-	file_name = straconcat(elinks_home, GLOBAL_HISTORY_FILENAME, NULL);
+	file_name = straconcat(elinks_home, GLOBAL_HISTORY_FILENAME,
+			       (unsigned char *) NULL);
 	if (!file_name) return;
 
 	ssi = secure_open(file_name);

src/mime/mime.c

@@ -110,7 +110,8 @@ check_extension_type(unsigned char *extension)
 	if (!trimmed)
 		return NULL;
 
-	content_type = straconcat("application/x-", trimmed + 1, NULL);
+	content_type = straconcat("application/x-", trimmed + 1,
+				  (unsigned char *) NULL);
 	if (!content_type)
 		return NULL;
 

src/osdep/newwin.c

@@ -86,7 +86,8 @@ open_new_window(struct terminal *term, unsigned char *exe_name,
 		if (twterm) command = twterm;
 	}
 
-	command = straconcat(command, " ", exe_name, " ", param, NULL);
+	command = straconcat(command, " ", exe_name, " ", param,
+			     (unsigned char *) NULL);
 	if (!command) return;
 
 	exec_on_terminal(term, command, "", 2);

src/protocol/data.c

@@ -73,7 +73,8 @@ init_data_protocol_header(struct cache_entry *cached,
 	if (!type) return NULL;
 
 	/* Set fake content type */
-	head = straconcat("\r\nContent-Type: ", type, "\r\n", NULL);
+	head = straconcat("\r\nContent-Type: ", type, "\r\n",
+			  (unsigned char *) NULL);
 	mem_free(type);
 	if (!head) return NULL;
 

src/protocol/file/file.c

@@ -112,7 +112,7 @@ add_dir_entry(struct directory_entry *entry, struct string *page,
 
 		if (readlen > 0 && readlen != MAX_STR_LEN) {
 			buf[readlen] = '\0';
-			lnk = straconcat(" -> ", buf, NULL);
+			lnk = straconcat(" -> ", buf, (unsigned char *) NULL);
 		}
 
 		if (!stat(entry->name, &st) && S_ISDIR(st.st_mode))

src/protocol/http/http.c

@@ -657,7 +657,7 @@ http_send_header(struct socket *socket)
 			if (user[0]) {
 				unsigned char *proxy_data;
 
-				proxy_data = straconcat(user, ":", passwd, NULL);
+				proxy_data = straconcat(user, ":", passwd, (unsigned char *) NULL);
 				if (proxy_data) {
 					unsigned char *proxy_64 = base64_encode(proxy_data);
 
@@ -883,7 +883,8 @@ http_send_header(struct socket *socket)
 			unsigned char *id;
 
 			/* Create base64 encoded string. */
-			id = straconcat(entry->user, ":", entry->password, NULL);
+			id = straconcat(entry->user, ":", entry->password,
+					(unsigned char *) NULL);
 			if (id) {
 				unsigned char *base64 = base64_encode(id);
 

src/scripting/guile/core.c

@@ -54,7 +54,8 @@ init_guile(struct module *module)
 	/* Remember the current module. */
 	user_module = scm_current_module();
 
-	path = straconcat(elinks_home, GUILE_HOOKS_FILENAME, NULL);
+	path = straconcat(elinks_home, GUILE_HOOKS_FILENAME,
+			  (unsigned char *) NULL);
 	if (!path) return;
 
 	if (file_can_read(path)) {
@@ -76,7 +77,8 @@ init_guile(struct module *module)
 
 	mem_free(path);
 
-	path = straconcat(elinks_home, GUILE_USERHOOKS_FILENAME, NULL);
+	path = straconcat(elinks_home, GUILE_USERHOOKS_FILENAME,
+			  (unsigned char *) NULL);
 	if (!path) return;
 	if (file_can_read(path))
 		scm_c_primitive_load_path(path);

src/scripting/lua/core.c

@@ -639,7 +639,8 @@ eval_function(LS, int num_args, int num_results)
 static void
 do_hooks_file(LS, unsigned char *prefix, unsigned char *filename)
 {
-	unsigned char *file = straconcat(prefix, STRING_DIR_SEP, filename, NULL);
+	unsigned char *file = straconcat(prefix, STRING_DIR_SEP, filename,
+					 (unsigned char *) NULL);
 
 	if (!file) return;
 

src/scripting/ruby/core.c

@@ -233,7 +233,8 @@ init_ruby(struct module *module)
 	init_erb_module();
 
 	if (elinks_home) {
-		path = straconcat(elinks_home, RUBY_HOOKS_FILENAME, NULL);
+		path = straconcat(elinks_home, RUBY_HOOKS_FILENAME,
+				  (unsigned char *) NULL);
 
 	} else {
 		path = stracpy(CONFDIR STRING_DIR_SEP RUBY_HOOKS_FILENAME);

src/scripting/smjs/core.c

@@ -113,7 +113,8 @@ smjs_load_hooks(void)
 	assert(smjs_ctx);
 
 	if (elinks_home) {
-		path = straconcat(elinks_home, SMJS_HOOKS_FILENAME, NULL);
+		path = straconcat(elinks_home, SMJS_HOOKS_FILENAME,
+				  (unsigned char *) NULL);
 	} else {
 		path = stracpy(CONFDIR STRING_DIR_SEP SMJS_HOOKS_FILENAME);
 	}

src/util/file.c

@@ -187,7 +187,7 @@ get_tempdir_filename(unsigned char *name)
 	if (!tmpdir || !*tmpdir) tmpdir = getenv("TEMP");
 	if (!tmpdir || !*tmpdir) tmpdir = "/tmp";
 
-	return straconcat(tmpdir, "/", name, NULL);
+	return straconcat(tmpdir, "/", name, (unsigned char *) NULL);
 }
 
 unsigned char *
@@ -541,7 +541,8 @@ get_directory_entries(unsigned char *dirname, int get_hidden)
 		/* We allocate the full path because it is used in a few places
 		 * which means less allocation although a bit more short term
 		 * memory usage. */
-		name = straconcat(dirname, entry->d_name, NULL);
+		name = straconcat(dirname, entry->d_name,
+				  (unsigned char *) NULL);
 		if (!name) continue;
 
 		if (!init_string(&attrib)) {

src/util/secsave.c

@@ -151,7 +151,8 @@ secure_open_umask(unsigned char *file_name)
 		 */
 		int fd;
 		unsigned char *randname = straconcat(ssi->file_name,
-						     ".tmp_XXXXXX", NULL);
+						     ".tmp_XXXXXX",
+						     (unsigned char *) NULL);
 
 		if (!randname) {
 			secsave_errno = SS_ERR_OUT_OF_MEM;

src/util/string.h

@@ -50,11 +50,11 @@ void add_to_strn(unsigned char **str, const unsigned char *src);
 unsigned char *insert_in_string(unsigned char **dst, int pos,
 				const unsigned char *seq, int seqlen);
 
-/* Takes a list of strings where the last parameter _must_ be NULL and
- * concatenates them. */
+/* Takes a list of strings where the last parameter _must_ be
+ * (unsigned char *) NULL and concatenates them. */
 /* Returns the allocated string or NULL on allocation failure. */
 /* Example:
- *	unsigned char *abc = straconcat("A", "B", "C", NULL);
+ *	unsigned char *abc = straconcat("A", "B", "C", (unsigned char *) NULL);
  *	if (abc) return;
  *	printf("%s", abc);	-> print "ABC"
  *	mem_free(abc);		-> free memory used by @abc */

src/viewer/text/form.c

@@ -659,13 +659,13 @@ add_submitted_value_to_list(struct form_control *fc,
 		break;
 
 	case FC_IMAGE:
-	        name = straconcat(fc->name, ".x", NULL);
+	        name = straconcat(fc->name, ".x", (unsigned char *) NULL);
 		if (!name) break;
 		sub = init_submitted_value(name, "0", type, fc, position);
 		mem_free(name);
 		if (sub) add_to_list(*list, sub);
 
-		name = straconcat(fc->name, ".y", NULL);
+		name = straconcat(fc->name, ".y", (unsigned char *) NULL);
 		if (!name) break;
 		sub = init_submitted_value(name, "0", type, fc, position);
 		mem_free(name);

src/viewer/text/textarea.c

@@ -611,7 +611,7 @@ textarea_edit(int op, struct terminal *term_, struct form_state *fs_,
 			if (!ed || !*ed) ed = "vi";
 		}
 
-		ex = straconcat(ed, " ", fn, NULL);
+		ex = straconcat(ed, " ", fn, (unsigned char *) NULL);
 		if (!ex) {
 			unlink(fn);
 			goto free_and_return;