Re: Syntax file core dumps mc

[Roland Illig <roland illig gmx de>]

Roland Illig wrote:
> Ian Zagorskih wrote:
>
> > mc-4.6.1-pre4a
> >
> > Synopsis:
> >
> > Looks like mc core dumps when it cannot find "context default" section 
> > in syntax file.
>
>
> Thanks for the bug report. I can reproduce it, and I'm working on a 
> solution.

And here it is. The code that was erroneous was ugly, and so looks my 
patch. It adds a field to the editor that notes how many rules have been 
defined and takes its actions based on this number.

It has just been a weird idea to start an array with index 1 in C ...

I suggest that we replace code that uses NULL-terminated arrays with 
code that has an extra length (or count, or whatever) field. That way we 
can easily put assert()s before array indexes to ensure they are valid.

Roland

? mcedit-segv.patch
Index: edit-widget.h
===================================================================
RCS file: /cvsroot/mc/mc/edit/edit-widget.h,v
retrieving revision 1.24
diff -u -p -r1.24 edit-widget.h
--- edit-widget.h	3 Dec 2004 17:09:27 -0000	1.24
+++ edit-widget.h	15 Apr 2005 21:33:35 -0000
@@ -93,6 +93,7 @@ struct WEdit {
     /* syntax higlighting */
     struct _syntax_marker *syntax_marker;
     struct context_rule **rules;
+    size_t rules_count;		/* number of rules that are defined */
     long last_get_rule;
     struct syntax_rule rule;
     char *syntax_type;		/* description of syntax highlighting type being used */
Index: syntax.c
===================================================================
RCS file: /cvsroot/mc/mc/edit/syntax.c,v
retrieving revision 1.73
diff -u -p -r1.73 syntax.c
--- syntax.c	22 Feb 2005 17:00:38 -0000	1.73
+++ syntax.c	15 Apr 2005 21:33:35 -0000
@@ -678,6 +678,7 @@ edit_read_syntax_rules (WEdit *edit, FIL
     strcpy (whole_right, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_01234567890");
 
     r = edit->rules = g_malloc (alloc_contexts * sizeof (struct context_rule *));
+    edit->rules_count = 0;
 
     if (!edit->defines)
 	edit->defines = g_tree_new ((GCompareFunc) strcmp);
@@ -908,6 +909,7 @@ edit_read_syntax_rules (WEdit *edit, FIL
     if (num_contexts == -1) {
 	return line;
     }
+    edit->rules_count = num_contexts;
 
     {
 	char *first_chars, *p;
@@ -932,17 +934,18 @@ edit_read_syntax_rules (WEdit *edit, FIL
 
 void edit_free_syntax_rules (WEdit * edit)
 {
-    int i, j;
+    size_t i, j;
     if (!edit)
 	return;
     if (edit->defines)
 	destroy_defines (&edit->defines);
     if (!edit->rules)
 	return;
-    edit_get_rule (edit, -1);
+    if (edit->rules_count > 0)
+	edit_get_rule (edit, -1);
     syntax_g_free (edit->syntax_type);
     edit->syntax_type = 0;
-    for (i = 0; edit->rules[i]; i++) {
+    for (i = 0; i < edit->rules_count; i++) {
 	if (edit->rules[i]->keyword) {
 	    for (j = 0; edit->rules[i]->keyword[j]; j++) {
 		syntax_g_free (edit->rules[i]->keyword[j]->keyword);