[U-Boot] [PATCH] bootp: Fix bug in auto_load function

[Michal Simek]

Hi,

2011/8/31 Simon Glass <sjg at chromium.org>

> Hi Michal,
>
> On Wed, Aug 31, 2011 at 3:36 AM, Michal Simek <monstr at monstr.eu> wrote:
> > Patch: "Put common autoload code into auto_load() function"
> > (sha1: 093498669e77597635a24f326f11efeab213d394) is not simple code
> > cleanup but code change which introduce new bug.
> >
> > If autoload variable is not setup it worked as autoload=yes.
> >
> > Currently if autoload is not setup dhcp sends request in
> > forever loop.
>
> Thanks for bring this up - there was some discussion at the time I
> remember. Also please excuse the verbatim code in this email but I
> want it to be clear.
>
> The old code in v2011.03 is:
>
>                        /* Obey the 'autoload' setting */
>                        if ((s = getenv("autoload")) != NULL) {
>                                if (*s == 'n') {
>                                        /*
>                                         * Just use BOOTP to configure
> system;
>                                         * Do not use TFTP to load the
> bootfile.
>                                         */
>                                        NetState = NETLOOP_SUCCESS;
>                                        return;
> #if defined(CONFIG_CMD_NFS)
>                                } else if (strcmp(s, "NFS") == 0) {
>                                        /*
>                                         * Use NFS to load the bootfile.
>                                         */
>                                        NfsStart();
>                                        return;
> #endif
>                                }
>                        }
>                        TftpStart();
>                        return;
>
>
> and
>
>        if ((s = getenv("autoload")) != NULL) {
>                if (*s == 'n') {
>                        /*
>                         * Just use BOOTP to configure system;
>                         * Do not use TFTP to load the bootfile.
>                         */
>                        NetState = NETLOOP_SUCCESS;
>                        return;
> #if defined(CONFIG_CMD_NFS)
>                } else if (strcmp(s, "NFS") == 0) {
>                        /*
>                         * Use NFS to load the bootfile.
>                         */
>                        NfsStart();
>                        return;
> #endif
>                }
>        }
>
>        TftpStart();
>
>
> These two sites were changed to a call to auto_load:
>
> static void auto_load(void)
> {
>        const char *s = getenv("autoload");
>
>        if (s != NULL) {
>                if (*s == 'n') {
>                        /*
>                         * Just use BOOTP to configure system;
>                         * Do not use TFTP to load the bootfile.
>                         */
>                        NetState = NETLOOP_SUCCESS;
>                        return;
>                }
> #if defined(CONFIG_CMD_NFS)
>                if (strcmp(s, "NFS") == 0) {
>                        /*
>                         * Use NFS to load the bootfile.
>                         */
>                        NfsStart();
>                        return;
>                }
> #endif
>        TftpStart();
>        }
> }
>
>
> I don't see a change in the functionality here - I may be missing
> something so please can you explain?
>


just look at  TftpStart(); position in new and old code.
In new code is inside   if (s != NULL) { } part in old not which change
behavior.

Just do simple test run
set autoload
dhcp

on my system it loops forever.



>
> From my experience U-Boot has always performed an autoload unless you
> 'setenv autoload n', even if the variable is not set. From the README:
>
>  autoload      - if set to "no" (any string beginning with 'n'),
>                  "bootp" will just load perform a lookup of the
>                  configuration from the BOOTP server, but not try to
>                  load any image using TFTP
>
>
> which suggests that this is the correct behavior (i.e. it defaults to
> autoload=yes)
>

I am fine with that that if autoload var is not set it means autoload=yes.


>
> >
> > There are two options how to fix it:
> > 1. Move TftpStart() which is in this patch
> > 2. Change functionality if autoload is not setup, set NetSate and ends.
> >
> > @@ -165,7 +165,8 @@ static void auto_load(void)
> >                }
> >  #endif
> >        TftpStart();
> > -       }
> > +       } else
> > +               NetState = NETLOOP_SUCCESS;
> >  }
> >
> > CC: Eric Bénard <eric at eukrea.com>
> > CC: Simon Glass <sjg at chromium.org>
> > Signed-off-by: Michal Simek <monstr at monstr.eu>
> > ---
> >  net/bootp.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/net/bootp.c b/net/bootp.c
> > index 3db08ea..a003c42 100644
> > --- a/net/bootp.c
> > +++ b/net/bootp.c
> > @@ -164,8 +164,8 @@ static void auto_load(void)
> >                        return;
> >                }
> >  #endif
> > -       TftpStart();
> >        }
> > +       TftpStart();
> >  }
>
>
> Isn't this the opposite of the patch you want? I think you want to
> move TftpStart() inside the loop, like this:
>
> static void auto_load(void)
> {
>        const char *s = getenv("autoload");
>
>        if (s != NULL) {
>                if (*s == 'n') {
>                        /*
>                         * Just use BOOTP to configure system;
>                         * Do not use TFTP to load the bootfile.
>                         */
>                        NetState = NETLOOP_SUCCESS;
>                        return;
>                }
> #if defined(CONFIG_CMD_NFS)
>                if (strcmp(s, "NFS") == 0) {
>                        /*
>                         * Use NFS to load the bootfile.
>                         */
>                        NfsStart();
>                        return;
>                TftpStart();
>                }
> #endif
>        }
> }
>

Definitely this one - where TftpStart is not even called.

Michal