printk-add-interfaces-for-external-access-to-the-log-buffer-dont-use-ring-buffer.patch

   1 Key off of the log buffer rather than the kernel ring buffer as the
   2 latter is constantly cleared by userspace daemons.  Also, make sure
   3 we index into the buffer properly as pointed out by Tim Bird.
   4
   5 Signed-off-by: Mike Frysinger <vapier@gentoo.org>
   6 ---
   7 --- a/kernel/printk.c
   8 +++ b/kernel/printk.c
   9 @@ -168,7 +168,7 @@
  10   */
  11  int log_buf_get_len(void)
  12  {
  13 -       return log_end - log_start;
  14 +       return logged_chars;
  15  }
  16
  17  /*
  18 @@ -191,10 +191,9 @@
  19                 if (len > max)
  20                         len = max;
  21                 ret = len;
  22 -               while (len-- > 0) {
  23 -                       *dest = LOG_BUF(idx++);
  24 -                       ++dest;
  25 -               }
  26 +               idx += (log_end - max);
  27 +               while (len-- > 0)
  28 +                       dest[len] = LOG_BUF(idx + len);
  29         }
  30
  31         if (took_lock)