3 files changed, 36 insertions, 15 deletions

diff --git a/src/liolib.c b/src/liolib.c
index 6092cac..b0148e8 100644
--- a/src/liolib.c
+++ b/src/liolib.c
@@ -14,9 +14,9 @@
 #define LUA_LIB
 
 #include "lua.h"
-
 #include "lauxlib.h"
 #include "lualib.h"
+#include "teliva.h"
 
 
 
@@ -128,11 +128,17 @@ static int io_tostring (lua_State *L) {
 }
 
 
+static char iolib_errbuf[1024] = {0};
 static int io_open (lua_State *L) {
   const char *filename = luaL_checkstring(L, 1);
   const char *mode = luaL_optstring(L, 2, "r");
   FILE **pf = newfile(L);
-  *pf = fopen(filename, mode);
+  if (file_operations_allowed)
+    *pf = fopen(filename, mode);
+  else {
+    snprintf(iolib_errbuf, 1024, "app tried to open file '%s'; adjust its permissions (ctrl-p) if that is expected", filename);
+    Previous_message = iolib_errbuf;
+  }
   return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
 }
 
@@ -164,7 +170,12 @@ static int f_lines (lua_State *L) {
 static int io_lines (lua_State *L) {
   const char *filename = luaL_checkstring(L, 1);
   FILE **pf = newfile(L);
-  *pf = fopen(filename, "r");
+  if (file_operations_allowed)
+    *pf = fopen(filename, "r");
+  else {
+    snprintf(iolib_errbuf, 1024, "app tried to open file '%s'; adjust its permissions (ctrl-p) if that is expected", filename);
+    Previous_message = iolib_errbuf;
+  }
   if (*pf == NULL)
     fileerror(L, 1, filename);
   aux_lines(L, lua_gettop(L), 1);
diff --git a/src/teliva.c b/src/teliva.c
index f2814c2..1129dc3 100644
--- a/src/teliva.c
+++ b/src/teliva.c
@@ -32,6 +32,7 @@ void draw_menu_item(const char* key, const char* name) {
 }
 
 static void render_permissions(lua_State* L);
+char* Previous_message;
 static void draw_menu(lua_State* L) {
   attron(A_BOLD|A_REVERSE);
   color_set(COLOR_PAIR_MENU, NULL);
@@ -42,20 +43,28 @@ static void draw_menu(lua_State* L) {
   draw_menu_item("^e", "edit");
   draw_menu_item("^p", "perms");
 
-  /* render any app-specific items */
-  lua_getglobal(L, "menu");
-  int table = lua_gettop(L);
-  if (lua_istable(L, -1)) {
-    for (int i = 1; i <= luaL_getn(L, table); ++i) {
-      lua_rawgeti(L, table, i);
-      int menu_item = lua_gettop(L);
-      lua_rawgeti(L, menu_item, 1);  /* key */
-      lua_rawgeti(L, menu_item, 2);  /* value */
-      draw_menu_item(lua_tostring(L, -2), lua_tostring(L, -1));
-      lua_pop(L, 3);
+  /* if app ran successfully, render any app-specific items */
+  if (Previous_message == NULL) {
+    lua_getglobal(L, "menu");
+    int table = lua_gettop(L);
+    if (lua_istable(L, -1)) {
+      for (int i = 1; i <= luaL_getn(L, table); ++i) {
+        lua_rawgeti(L, table, i);
+        int menu_item = lua_gettop(L);
+        lua_rawgeti(L, menu_item, 1);  /* key */
+        lua_rawgeti(L, menu_item, 2);  /* value */
+        draw_menu_item(lua_tostring(L, -2), lua_tostring(L, -1));
+        lua_pop(L, 3);
+      }
     }
+    lua_pop(L, 1);
+  }
+  else {
+    /* otherwise render the flash message */
+    attron(COLOR_PAIR(COLOR_PAIR_ERROR));
+    addstr(Previous_message);
+    attroff(COLOR_PAIR(COLOR_PAIR_ERROR));
   }
-  lua_pop(L, 1);
 
   /* render app permissions on the right */
   render_permissions(L);
diff --git a/src/teliva.h b/src/teliva.h
index bf01c11..42ebdc7 100644
--- a/src/teliva.h
+++ b/src/teliva.h
@@ -151,6 +151,7 @@ enum color_pair {
 
 /* Integrate with Lua VM */
 extern char** Argv;
+extern char* Previous_message;
 extern int handle_image(lua_State* L, char** argv, int n);
 extern void developer_mode(lua_State* L);
 extern void permissions_mode(lua_State* L);