Patch/Bugfix for BOOTP in rtems-ss-20020205

[Till Straumann]

Thomas Doerfler wrote:

> Hi Chris,
>
> ok, here is a corrected verison of my patch. Thank you for
> your comments!
>
> wkr,
>         Thomas.

OOps - I was too fast with my last posting. IMO, it is not easily
asserted that processOptions() is NOT called multiple times -
hence you could generate a memory leak. Therefore, I would
free() before strdup() [note it's to call free with a 0 arg
- your patch could also omit the NULL test]

My suggested version of the patch would read:

-- Till


diff -c bootp_subr.c.orig bootp_subr.c
*** bootp_subr.c.orig Tue Mar 19 11:24:42 2002
--- bootp_subr.c Tue Mar 19 11:34:31 2002
***************
*** 694,700 ****
  static char dhcp_gotlogserver = 0;
  static struct sockaddr_in dhcp_netmask;
  static struct sockaddr_in dhcp_gw;
! static char *dhcp_hostname;

  static void
  processOptions (unsigned char *optbuf, int optbufSize)
--- 694,700 ----
  static char dhcp_gotlogserver = 0;
  static struct sockaddr_in dhcp_netmask;
  static struct sockaddr_in dhcp_gw;
! static char *dhcp_hostname=0;

  static void
  processOptions (unsigned char *optbuf, int optbufSize)
***************
*** 801,806 ****
--- 801,807 ----
        if (sethostname (p, len) < 0)
          panic("Can't set host name");
        printf("Hostname is %s\n", p);
+       free(dhcp_hostname);
        dhcp_hostname = strdup(p);
        break;

***************
*** 904,910 ****
        update_files = 0;
      }

!   memset(dhcp_hostname, 0, sizeof(dhcp_hostname));

    /*
     * Find a network interface.
--- 905,912 ----
        update_files = 0;
      }

!   free(dhcp_hostname);
!   dhcp_hostname=0;

    /*
     * Find a network interface.


>
>
> > Thomas Doerfler wrote:
> > >
> > > Hm, good question. At least it would not hurt. But the line I
> > > complaint is at the start of bootpc_init, long before any
> > > bootp options are processed. So at least at the first run of
> > > bootpc_init, "dhcp_hostname" is definitely NULL.
> > >
> >
> > Any future runs if called could have dhcp_hostname set so we should free
> > the memory. It is allocated using strdup.
> >
> > > The question is: can bootpc_init be called multiple times?
> > > Normally it will only be called once after system boot, but
> > > are there other situations?
> >
> > A system may have some form of redundant network configuration and so
> > need to obtain a network address. This is just an example not a
> > recommendation for a network design.
> >
> > --
> >  Chris Johns, cjohns at cybertec.com.au
>
> --------------------------------------------
> IMD Ingenieurbuero fuer Microcomputertechnik
> Thomas Doerfler           Herbststrasse 8
> D-82178 Puchheim          Germany
> email:    Thomas.Doerfler at imd-systems.de
> PGP public key available at: http://www.imd-
> systems.de/pgp_key.htm
>
>   ------------------------------------------------------------------------
> --- rtems-ss-20020205/c/src/libnetworking/nfs/bootp_subr.c      Wed Sep 19 19:30:38 2001
> +++ /usr/local/projects/sandbox/zem40/rtems_patch/bootp_subr.c  Tue Mar 19 12:39:24 2002
> @@ -902,12 +902,15 @@
>      if (rtems_create_root_fs () < 0) {
>        printf("Error creating the root filesystem.\nFile not created.\n");
>        update_files = 0;
>      }
>
> -  memset(dhcp_hostname, 0, sizeof(dhcp_hostname));
> -
> +  if (dhcp_hostname != NULL) {
> +    free(dhcp_hostname);
> +    dhcp_hostname = NULL;
> +  }
> +
>    /*
>     * Find a network interface.
>     */
>    for (ifp = ifnet; ifp != 0; ifp = ifp->if_next)
>      if ((ifp->if_flags &