[U-Boot] cmd/fdt: support single value replacement within an array

[Hannes Schmelzer]

Laurent Pinchart <laurent.pinchart at ideasonboard.com> schrieb am 04.08.2017 
23:23:19:

> Hi Hannes,
Hi Laurent,

as told a few days ago i'm now coming back to this issue.

> 
> (I'm not subscribed to the list, please keep me CC'ed on replies)
subscribing to the list would be a great idea, so you're always up to date 
whats going on ;-)

> 
> On Tuesday 30 May 2017 13:05:00 Hannes Schmelzer wrote:
> > With this commit we can modify single values within an array of a dts
> > property.
> 
> But with this commit U-Boot crashes if you try to create a new property 
with 
> the fdt set command :-/
> 
> I've tested v2017.07 with the commit reverted, and fdt set works again 
for me. 
> The issue is that your fdt_getprop() call fails and return NULL with len 
set 
> to -1. You can easily imagine what the memcpy() following it will do.

Yes. Your'e right with that.

I just checked most current source (...), there were changes regarding 
this issue.
Tom introduced a check against the fail of fdt_getprop(...) call.

http://git.denx.de/?p=u-boot.git;a=commitdiff;h=99bb38e2cce9d99238458e0f6d1880c6d2e80a4d

Can you please try with your testcase with most current source again?

please let us know if the problem is fixed with this.

cheers,
Hannes

(....)

> > ---
> > 
> >  cmd/fdt.c | 29 +++++++++++++++++++++--------
> >  1 file changed, 21 insertions(+), 8 deletions(-)
> > 
> > diff --git a/cmd/fdt.c b/cmd/fdt.c
> > index a21415d..e55102a 100644
> > --- a/cmd/fdt.c
> > +++ b/cmd/fdt.c
> > @@ -257,6 +257,7 @@  static int do_fdt(cmd_tbl_t *cmdtp, int flag, int 
argc,
> > char * const argv[])> 
> >        char *prop;      /* property */
> >        int  nodeoffset;   /* node offset from libfdt */
> >        static char data[SCRATCHPAD];   /* storage for the property */
> > +      const void *ptmp;
> >        int  len;      /* new length of the property */
> >        int  ret;      /* return value */
> > 
> > @@ -268,13 +269,6 @@  static int do_fdt(cmd_tbl_t *cmdtp, int flag, 
int
> > argc, char * const argv[])> 
> >        pathp  = argv[2];
> >        prop   = argv[3];
> > 
> > -      if (argc == 4) {
> > -         len = 0;
> > -      } else {
> > -         ret = fdt_parse_prop(&argv[4], argc - 4, data, &len);
> > -         if (ret != 0)
> > -            return ret;
> > -      }
> > 
> >        nodeoffset = fdt_path_offset (working_fdt, pathp);
> >        if (nodeoffset < 0) {
> > @@ -286,6 +280,21 @@  static int do_fdt(cmd_tbl_t *cmdtp, int flag, 
int
> > argc, char * const argv[])
> >           return 1;
> >        }
> > 
> > +      if (argc == 4) {
> > +         len = 0;
> > +      } else {
> > +         ptmp = fdt_getprop(working_fdt, nodeoffset, prop,
> > &len);
> > +         if (len > SCRATCHPAD) {
> > +            printf("prop (%d) doesn't fit in scratchpad!
> > \n",
> > +                   len);
> > +            return 1;
> > +         }
> > +         memcpy(data, ptmp, len);
> > +         ret = fdt_parse_prop(&argv[4], argc - 4, data, &len);
> > +         if (ret != 0)
> > +            return ret;
> > +      }
> > +
> >        ret = fdt_setprop(working_fdt, nodeoffset, prop, data, len);
> >        if (ret < 0) {
> >           printf ("libfdt fdt_setprop(): %s\n",
> > fdt_strerror(ret));
> > @@ -766,7 +775,11 @@  static int fdt_parse_prop(char * const *newval, 
int
> > count, char *data, int *len)
> >           cp = newp;
> >           tmp = simple_strtoul(cp, &newp, 0);
> > 
> > -         *(fdt32_t *)data = cpu_to_fdt32(tmp);
> > +         if (*cp != '?')
> > +            *(fdt32_t *)data = cpu_to_fdt32(tmp);
> > +         else
> > +            newp++;
> > +
> > 
> >           data  += 4;
> >           *len += 4;