close_editor problem of RTEMS4.13/5.1

[chenjin_zhong]

Hi, I find when close editor in shell console.some errors will occur. I check and analyse the source code of medit.c. the code fragment is listed as follows.

#if defined(rtems)

case ctrl('w'): ed = ed->env->current; close_editor(ed); break;

#else

case ctrl('w'): close_editor(ed); ed = ed->env->current; break;

#endif

static void close_editor(struct editor *ed) {

struct env *env = ed->env;
if (ed->dirty) {

display_message(ed, "Close %s without saving changes (y/n)? ", ed->filename);
if (!ask()) {

ed->refresh = 1;
return;

}

}

delete_editor(ed);

ed = env->current;
if (!ed) {

ed = create_editor(env);
new_file(ed, "");

}
ed->refresh = 1;

}

static void delete_editor(struct editor *ed) {

if (ed->next == ed) {

ed->env->current = NULL;

} else {

ed->env->current = ed->prev;

}
ed->next->prev = ed->prev;
ed->prev->next = ed->next;
if (ed->start) free(ed->start);

clear_undo(ed);

free(ed);

}

as seen above, if the macro rtems is defined. the delete_editor function will free ed pointer. Therefore, after the next loop, the ed is an invalid pointer.I have checked the code of ​https://github.com/ringgaard/sanos/blob/master/src/utils/edit/edit.c. the code is as follows.

case ctrl('w'): close_editor(ed); ed = ed->env->current; break;

[Chris Johns]

The original code is wrong and the change made by Joel due to Coverity is also wrong because the ed passed into close_editor() is the next editor and not the one we want closed.

[Chris Johns <chrisj@…>]

In 45f60cf/rtems:

libmisc/shell/edit: Fix closing the editor

Closes #4564