On Monday 26 January 2009 04:30:36 pm Wolfgang Denk wrote:

Dear E Robertson,

In message 200901261453.10434.e.robertson.svg@gmail.com you wrote:

...

It seems that sprintf() is modifying at least two bytes from the source and I have duplicate this with different varibles. For instance, I have a mac address defined as unsigned char [6]: Doing the following sets the environment variable correctly, however bytes [0] and [1], are modified at the source.

sprintf(env_ethaddr,"%02X:%02X:%02X:%02X:%02X:%02X", MACAddress[0], MACAddress[1], MACAddress[2], MACAddress[3], MACAddress[4], MACAddress[5]);

Has anyone noticed this before? I don't think the machine matters but I am building for an arm at91.

Hmm... I think I wouldbe surprised. What exactly does your test code look like?

I tried this one:

... unsigned char buf[128]; unsigned char a[6] = { 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, }; int i; ... printf ("Before: "); for (i=0; i<6; ++i) printf (" %02X",a[i]); putc ('\n'); sprintf (buf, "%02X:%02X:%02X:%02X:%02X:%02X", a[0], a[1], a[2], a[3], a[4], a[5]); printf ("After: "); for (i=0; i<6; ++i) printf (" %02X",a[i]); putc ('\n'); printf ("buf="%s"\n", buf); ...

And this is what I got:

Before: 11 22 33 44 55 66 After: 11 22 33 44 55 66 buf="11:22:33:44:55:66"

Hi,

I did the following: memcpy (gd->bd->bi_enetaddr, MACAddress, sizeof(gd->bd->bi_enetaddr)); memcpy (dupMACAddress, MACAddress, sizeof(dupMACAddress));

printf("Before %02X:%02X:%02X:%02X:%02X:%02X\n",dupMACAddress[0], dupMACAddress[1], dupMACAddress[2], dupMACAddress[3], dupMACAddress[4], dupMACAddress[5]);

sprintf(env_ethaddr,"%02X:%02X:%02X:%02X:%02X:%02X",dupMACAddress[0], dupMACAddress[1], dupMACAddress[2], dupMACAddress[3], dupMACAddress[4], dupMACAddress[5]); printf("After %02X:%02X:%02X:%02X:%02X:%02X\n",dupMACAddress[0], dupMACAddress[1], dupMACAddress[2], dupMACAddress[3], dupMACAddress[4], dupMACAddress[5]); printf("ethaddr %02X:%02X:%02X:%02X:%02X:%02X\n",gd->bd->bi_enetaddr[0], gd->bd->bi_enetaddr[1], gd->bd->bi_enetaddr[2], gd->bd->bi_enetaddr[3], gd->bd->bi_enetaddr[4], gd->bd->bi_enetaddr[5]);

and I got this:

Before 00:04:A6:00:6A:E6 After 36:00:A6:00:6A:E6 ethaddr 00:04:A6:00:6A:E6 Alse env_ethaddr has the correct correct.

I make a duplicate before did the sprintf. I'm also on v 1.3.4 and haven't tried it on the latest git.

Looks sane to me...

Best regards,

Wolfgang Denk

On Tuesday 27 January 2009 02:31:52 pm Scott Wood wrote:

E Robertson wrote:

...

I did the following: memcpy (gd->bd->bi_enetaddr, MACAddress, sizeof(gd->bd->bi_enetaddr)); memcpy (dupMACAddress, MACAddress, sizeof(dupMACAddress));

printf("Before %02X:%02X:%02X:%02X:%02X:%02X\n",dupMACAddress[0],

dupMACAddress[1], dupMACAddress[2], dupMACAddress[3], dupMACAddress[4], dupMACAddress[5]);

sprintf(env_ethaddr,"%02X:%02X:%02X:%02X:%02X:%02X",dupMACAddress[0],

dupMACAddress[1], dupMACAddress[2], dupMACAddress[3], dupMACAddress[4], dupMACAddress[5]); printf("After %02X:%02X:%02X:%02X:%02X:%02X\n",dupMACAddress[0], dupMACAddress[1], dupMACAddress[2], dupMACAddress[3], dupMACAddress[4], dupMACAddress[5]); printf("ethaddr %02X:%02X:%02X:%02X:%02X:%02X\n",gd->bd->bi_enetaddr[0], gd->bd->bi_enetaddr[1], gd->bd->bi_enetaddr[2], gd->bd->bi_enetaddr[3], gd->bd->bi_enetaddr[4], gd->bd->bi_enetaddr[5]);

and I got this:

Before 00:04:A6:00:6A:E6 After 36:00:A6:00:6A:E6 ethaddr 00:04:A6:00:6A:E6 Alse env_ethaddr has the correct correct.

Looks like you're overflowing a buffer -- 0x36 0x00 are the last two bytes of the sprintf output. Where are env_ethaddr and dupMACaddress defined?

Ah!! Yes, big user error! I forgot about the string termination.

Thanks.

-Scott