Re: [RFA] deleting breakpoints inside of 'commands' (again)

[Michael Snyder <msnyder at cygnus dot com>]

Fernando Nasser wrote:
> 
> Don Howard wrote:
> >
> > This implementation makes a copy of commands list that contain 'delete'
> > or 'clear' commands.  It also attempts to clean up when an error in
> > encountered.  Comments?

Don, I hesitate to say anything, because I know this has been beaten
to death already, but does this method account for the possibility that
the list might contain a call to another user command which in turn
calls "delete" or "clear"?

Michael



> >
> 
> This is much nicer.  Thanks!
> 
> The cli part is approved.
> 
> Fernando
> 
> P.S.: An extra blank line slipped in at the end of your breakpoint.c
> patch.
> 
> > 2001-10-31  Don Howard  <dhoward@redhat.com>
> >
> >         * breakpoint.c (bpstat_do_actions): Avoid deleting a 'commands'
> >         list while executing that list.  Thanks to Pierre Muller
> >         <muller@ics.u-strasbg.fr> for suggesting this implementation.
> >         (cleanup_dup_command_lines): New function.
> >         * cli/cli-script.c (dup_command_lines): New function.
> >         * defs.h: Added declaration of new function.
> >
> > Index: breakpoint.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/breakpoint.c,v
> > retrieving revision 1.55
> > diff -p -u -w -r1.55 breakpoint.c
> > --- breakpoint.c        2001/10/20 23:54:29     1.55
> > +++ breakpoint.c        2001/10/31 21:48:28
> > @@ -1790,6 +1790,12 @@ cleanup_executing_breakpoints (PTR ignor
> >    executing_breakpoint_commands = 0;
> >  }
> >
> > +static void
> > +cleanup_dup_command_lines (PTR cmds)
> > +{
> > +  free_command_lines (cmds);
> > +}
> > +
> >  /* Execute all the commands associated with all the breakpoints at this
> >     location.  Any of these commands could cause the process to proceed
> >     beyond this point, etc.  We look out for such changes by checking
> > @@ -1800,7 +1806,6 @@ bpstat_do_actions (bpstat *bsp)
> >  {
> >    bpstat bs;
> >    struct cleanup *old_chain;
> > -  struct command_line *cmd;
> >
> >    /* Avoid endless recursion if a `source' command is contained
> >       in bs->commands.  */
> > @@ -1824,17 +1829,40 @@ top:
> >
> >    breakpoint_proceeded = 0;
> >    for (; bs != NULL; bs = bs->next)
> > +    {
> > +      struct command_line *cmd;
> > +      struct cleanup *new_old_chain;
> > +
> > +      cmd = 0;
> > +      new_old_chain = 0;
> > +
> > +      /* If the command list for this breakpoint includes a statement
> > +        that deletes breakpoints, we assume that the target may be
> > +        this breakpoint, so we make a copy of the command list to
> > +        avoid walking a list that has been deleted. */
> > +
> > +      for (cmd = bs->commands; cmd; cmd = cmd->next)
> >      {
> > -      cmd = bs->commands;
> > -      while (cmd != NULL)
> > +         if (!new_old_chain &&
> > +             (strncmp (cmd->line, "dele", 4) == 0 ||
> > +              strncmp (cmd->line, "clea", 4) == 0))
> >         {
> > +             cmd = dup_command_lines (cmd);
> > +             new_old_chain = make_cleanup (cleanup_dup_command_lines, cmd);
> > +           }
> > +
> >           execute_control_command (cmd);
> >
> >           if (breakpoint_proceeded)
> >             break;
> > -         else
> > -           cmd = cmd->next;
> >         }
> > +
> > +      if (new_old_chain)
> > +       {
> > +         free_command_lines (&cmd);
> > +         discard_cleanups (new_old_chain);
> > +       }
> > +
> >        if (breakpoint_proceeded)
> >         /* The inferior is proceeded by the command; bomb out now.
> >            The bpstat chain has been blown away by wait_for_inferior.
> > @@ -1844,6 +1872,7 @@ top:
> >        else
> >         bs->commands = NULL;
> >      }
> > +
> >
> >    executing_breakpoint_commands = 0;
> >    discard_cleanups (old_chain);
> > Index: defs.h
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/defs.h,v
> > retrieving revision 1.64
> > diff -p -u -w -r1.64 defs.h
> > --- defs.h      2001/10/17 20:35:31     1.64
> > +++ defs.h      2001/10/31 21:48:28
> > @@ -843,6 +843,7 @@ struct command_line
> >  extern struct command_line *read_command_lines (char *, int);
> >
> >  extern void free_command_lines (struct command_line **);
> > +extern struct command_line * dup_command_lines (struct command_line *);
> >
> >  /* To continue the execution commands when running gdb asynchronously.
> >     A continuation structure contains a pointer to a function to be called
> > Index: cli/cli-script.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/cli/cli-script.c,v
> > retrieving revision 1.7
> > diff -p -u -w -r1.7 cli-script.c
> > --- cli-script.c        2001/06/17 15:16:12     1.7
> > +++ cli-script.c        2001/10/31 21:48:29
> > @@ -1005,6 +1005,59 @@ read_command_lines (char *prompt_arg, in
> >    return (head);
> >  }
> >
> > +/* Duplicate a chain of struct command_line's */
> > +
> > +struct command_line *
> > +dup_command_lines (struct command_line *l)
> > +{
> > +  struct command_line *dup = NULL;
> > +  register struct command_line *next = NULL;
> > +
> > +
> > +  for (; l ; l = l->next)
> > +    {
> > +      if (next == NULL)
> > +       {
> > +         dup = next = (struct command_line *)
> > +           xmalloc (sizeof (struct command_line));
> > +       }
> > +      else
> > +       {
> > +         next->next = (struct command_line *)
> > +           xmalloc (sizeof (struct command_line));
> > +
> > +         next = next->next;
> > +       }
> > +
> > +
> > +      if (next == NULL)
> > +       return NULL;
> > +
> > +
> > +      next->next = NULL;
> > +      next->line = xstrdup (l->line);
> > +      next->control_type = l->control_type;
> > +      next->body_count = l->body_count;
> > +
> > +
> > +      if (l->body_count > 0)
> > +       {
> > +         int i;
> > +         struct command_line **blist = l->body_list;
> > +
> > +         next->body_list =
> > +           (struct command_line **) xmalloc (sizeof (struct command_line *)
> > +                                             * l->body_count);
> > +
> > +         for (i = 0; i < l->body_count; i++, blist++)
> > +           next->body_list[i] = dup_command_lines (*blist);
> > +       }
> > +    }
> > +
> > +  return dup;
> > +}
> > +
> > +
> >  /* Free a chain of struct command_line's.  */
> >
> >  void
> >
> > --
> > -Don
> > dhoward@redhat.com
> > gdb engineering
> 
> --
> Fernando Nasser
> Red Hat Canada Ltd.                     E-Mail:  fnasser@redhat.com
> 2323 Yonge Street, Suite #300
> Toronto, Ontario   M4P 2C9