Hi all, I have been looking at MAC addr obtaining procedure in lib_arm/board.c and I am puzzled with this implementation :
/* MAC Address */ { int i; ulong reg; char *s, *e; char tmp[64];
i = getenv_r ("ethaddr", tmp, sizeof (tmp)); s = (i > 0) ? tmp : NULL;
*for (reg = 0; reg < 6; ++reg) { gd->bd->bi_enetaddr[reg] = s ? simple_strtoul (s, &e, 16) : 0; if (s) s = (*e) ? e + 1 : e;* } }
Here are my questions: 1) In which format is kept the addr in environment (i.e. why do we allocate 64 byte buffer tmp)? This is a little bit tricky to see from the code, so I thought maybe somebody will know.
2) In my opinion - there should be some delimiters (maybe ':') in this eth addr string in environment, so we are here jumping over them :* if (s) s = (*e) ? e + 1 : e; *but I still cannot see - how long are these strings between delimiters? (Because when you call simple_strtoul(), it will proceed to the first non-digit character, so who knows how long. As long as simple_stroul() is concerned, if it do not meet nonhexdigit char, it can go to Moon and beyond). Why we did not took two chars to represent each of 6 bytes + delimiters (':'), which would make 6*2 + 5 = 11, which should be the length of the tmp buffer. Then take two-by-two chars and transform them into number. What am I missing here?
Thanks and best regards, Drasko