Tom's patch releasing near f-nodes on Int 24 that returns to user

git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/branches/UNSTABLE@1041 6ac86273-5f31-0410-b378-82cca8765d1b

kernel/inthndlr.c

@@ -411,7 +411,13 @@ dispatch:
   }
   /* Clear carry by default for these functions */
 
-
+  /* see PATCH TE 5 jul 04 explanation at end */
+  if (ErrorMode && lr.AH > 0x0c && lr.AH != 0x30 && lr.AH != 0x59)
+  {
+    ErrorMode = 0;
+    fnode[0].f_count = 0;    /* don't panic - THEY ARE unused !! */
+    fnode[1].f_count = 0;
+  }
   /* Check for Ctrl-Break */
   if (break_ena || (lr.AH >= 1 && lr.AH <= 5) || (lr.AH >= 8 && lr.AH <= 0x0b))
     check_handle_break(&syscon);
@@ -1499,6 +1505,31 @@ exit_dispatch:
   r->ES = lr.ES;
 real_exit:;
 
+  /* PATCH !!       TE 5 JUL 04
+     what happened:
+     Application does FindFirst("I:\*.*");
+     this fails, and causes Int24
+     this sets ErrorMode, and calls Int24
+     Application decides NOT to return to DOS,
+     but instead pop the stack and return to itself
+     (this is legal; see RBIL/INT 24 description
+
+     a) now the alloc()'ed fnode[0] never gets free()'ed
+     b) errormode NEVER gets set back to 0 unyil exit()
+
+     I have NO idea how real DOS handles this;
+     the appended patch cures the worst symptoms
+  */
+  if (fnode[0].f_count != 0 ||
+      fnode[1].f_count != 0 )
+  {
+    if (ErrorMode == 0)
+      put_string("near_fnodes not 0"); /* panic ?? */
+    fnode[0].f_count = 0;    /* don't panic - THEY ARE unused !! */
+    fnode[1].f_count = 0;
+  }
+  /* PATCH !! END    TE 5 JUL 04 */
+
 #ifdef DEBUG
   if (bDumpRegs)
   {