Make getcwd match the posix variant, make get_current_file() behave similar to it and add a few sanity checks.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27903 a1c6a512-1295-4272-9138-f99709370657

apps/root_menu.c

@@ -252,7 +252,11 @@ static int browser(void* param)
     switch ((intptr_t)param)
     {
         case GO_TO_FILEBROWSER:
-            get_current_file(last_folder, MAX_PATH);
+            if (!get_current_file(last_folder, MAX_PATH))
+            {
+                last_folder[0] = '/';
+                last_folder[1] = '\0';
+            }
         break;
 #ifdef HAVE_TAGCACHE
         case GO_TO_DBBROWSER:

apps/tree.c

@@ -511,17 +511,17 @@ void resume_directory(const char *dir)
 
 /* Returns the current working directory and also writes cwd to buf if
    non-NULL.  In case of error, returns NULL. */
-char *getcwd(char *buf, int size)
+char *getcwd(char *buf, size_t size)
 {
     if (!buf)
         return tc.currdir;
-    else if (size > 0)
+    else if (size)
     {
-        strlcpy(buf, tc.currdir, size);
-        return buf;
+        if (strlcpy(buf, tc.currdir, size) < size)
+            return buf;
     }
-    else
-        return NULL;
+    /* size == 0, or truncation in strlcpy */
+    return NULL;
 }
 
 /* Force a reload of the directory next time directory browser is called */
@@ -530,19 +530,28 @@ void reload_directory(void)
     reload_dir = true;
 }
 
-void get_current_file(char* buffer, int buffer_len)
+char* get_current_file(char* buffer, size_t buffer_len)
 {
 #ifdef HAVE_TAGCACHE
     /* in ID3DB mode it is a bad idea to call this function */
     /* (only happens with `follow playlist') */
     if( *tc.dirfilter == SHOW_ID3DB )
-        return;
+        return NULL;
 #endif
 
     struct entry* dc = tc.dircache;
     struct entry* e = &dc[tc.selected_item];
-    snprintf(buffer, buffer_len, "%s/%s", getcwd(NULL,0),
-                                          tc.dirlength ? e->name : "");
+    if (getcwd(buffer, buffer_len))
+    {
+        if (tc.dirlength)
+        {
+            strlcat(buffer, "/", buffer_len);
+            if (strlcat(buffer, e->name, buffer_len) >= buffer_len)
+                return NULL;
+        }
+        return buffer;
+    }
+    return NULL;
 }
 
 /* Allow apps to change our dirfilter directly (required for sub browsers) 

apps/tree.h

@@ -73,13 +73,13 @@ struct tree_context {
 void tree_drawlists(void);
 void tree_mem_init(void) INIT_ATTR;
 void tree_gui_init(void) INIT_ATTR;
-void get_current_file(char* buffer, int buffer_len);
+char* get_current_file(char* buffer, size_t buffer_len);
 void set_dirfilter(int l_dirfilter);
 void set_current_file(char *path);
 int rockbox_browse(const char *root, int dirfilter);
 bool create_playlist(void);
 void resume_directory(const char *dir);
-char *getcwd(char *buf, int size);
+char *getcwd(char *buf, size_t size);
 void reload_directory(void);
 bool check_rockboxdir(void);
 struct tree_context* tree_get_context(void);