Re: normal/cmdline bug & patch

[Tomas Ebenlendr]

Oh sorry, another bug found. I will wait at least one hour before
submitting any patch, so I won't post too many messages.

Here is complete patch of normal/cmdline.c (grub_history_set)

> 
> Ok here is another version of the patch with two more bugs fixed:
> 
> bug1 ... hist_end does not point to last entry but to first empty.
> bug2 ... pos can underflow, but not overflow
> bug3 ... correction must act as 'modulo' so adding modulo value is right
>     way
> bug4 ... if hist_pos == hist_end, we need ot copy nothing, all lines were
>     copied.
> 
  - now it is fixed the right way. Before I fixed it, so another bug
    occur when buffer is full.
bug5 ... something was copied when hist_end < hist_pos, but it was
    definitely not what should be copied.

I think this function must have been written very late at nigt.

Now I will try to write 'chain' module (normal mode command for
'_chain'). 

---------

diff -ur grub2_x/ChangeLog grub2_work_xxx/ChangeLog
--- grub2_x/ChangeLog   2004-06-15 19:19:04.000000000 +0200
+++ grub2_work_xxx/ChangeLog    2004-06-15 19:24:42.000000000 +0200
@@ -1,3 +1,10 @@
+2004-06-15  Tomas Ebenlendr <address@hidden>
+
+        Bugfix of cmdline history (normal mode).
+
+       * normal/commandline.c (grub_set_history): History reallocating
+       was completely bad (about 5 brainos), all fixed.
+
 2004-05-24  Marco Gerards  <address@hidden>
 
        Add support for UFS version 1 and 2.  Add support for the minix
diff -ur grub2_x/normal/cmdline.c grub2_work_xxx/normal/cmdline.c
--- grub2_x/normal/cmdline.c    2004-06-15 19:18:52.000000000 +0200
+++ grub2_work_xxx/normal/cmdline.c     2004-06-15 19:14:15.000000000 +0200
@@ -52,33 +52,35 @@
          int delsize = hist_used - newsize;
          hist_used = newsize;
 
-         for (i = 0; i < delsize; i++)
+         for (i = 1; i <= delsize; i++)
            {
              int pos = hist_end - i;
-             if (pos > hist_size)
-               pos -= hist_size;
+             if (pos < 0)
+               pos += hist_size;
              grub_free (old_hist_lines[pos]);
            }
 
          hist_end -= delsize;
          if (hist_end < 0)
-           hist_end = hist_size - hist_end;
+           hist_end += hist_size;
        }
 
      if (hist_pos < hist_end)
        grub_memmove (hist_lines, old_hist_lines + hist_pos,
                      (hist_end - hist_pos) * sizeof (char *));
-       else
+       else if (hist_used)
        {
-         /* Copy the first part.  */
-         grub_memmove (hist_lines, old_hist_lines,
-                       hist_pos * sizeof (char *));
+         /* old_hist_lines: 0 <older part> hist_end <empty> hist_pos <newer 
part> */
+         /* entry at hist_end is empty, at hist_pos contains first entry */
 
-
-         /* Copy the last part.  */
-         grub_memmove (hist_lines + hist_pos, old_hist_lines + hist_pos,
+         /* Copy the older part.  */
+         grub_memmove (hist_lines, old_hist_lines + hist_pos,
                        (hist_size - hist_pos) * sizeof (char *));
 
+         /* Copy the newer part. */
+         grub_memmove (hist_lines + hist_size - hist_pos, old_hist_lines,
+                       hist_end * sizeof (char *));
+
        }
     }
 
-- 
                                 Tomas 'ebi' Ebenlendr
                                 http://get.to/ebik
                                 PF 2004.45578118675