Dear Timur Tabi,
In message 4DBB2723.4050408@freescale.com you wrote:
I disagree. It's quite clear what I'm trying to do. I'm trying to insert a
This is your opinion. I disagree.
NULL character into a string. Since device tree properties use a NULL to delimit multiple strings, it's clear that this is what the "0" is for.
Wrong data type. In C strings are _terminated_ by '\0' characters, so using functions that are designed to deal with C strings are obviously not the right tool to deal with data structures that have _embedded_ NUL characters.
If you try, it quickly gets ugly like the code I rejected.
For example, who gives you any guarantee that sprintf() will continue to append characters after it inserted the first NUL character? A clever implementation could optimize this and return immediately after seeing a NUL...
Look at the original code:
len = sprintf(compat_buf, "fsl,%c%s-l2-cache-controller", tolower(cpu->name[0]), cpu->name + 1);
sprintf(&compat_buf[len + 1], "cache");
I think my patch is clearer than this. In fact, because the original code was so obscure, there was a bug in it. I could have done this:
Why exactly do you think you have to use sprintf() to append a constant string like "cache"?
If you want to make clean what's intended, then use something like this:
len = sprintf(print_buf, "fsl,%c%s-l2-cache-controller", tolower(cpu->name[0]), cpu->name + 1); /* Include NUL characters */ memcpy(compat_buf, print_buf, len + 1); memcpy(compat_buf + len + 1, "cache", sizeof("cache"));
If you want to optimize (I'm a fan of small memory footprint, but I'm also a fan of readable code), use
len = sprintf(compat_buf, "fsl,%c%s-l2-cache-controller", tolower(cpu->name[0]), cpu->name + 1); /* Include NUL characters */ memcpy(compat_buf + len + 1, "cache", sizeof("cache"));
etc.
Best regards,
Wolfgang Denk