Re: [PATCH] Add support for mkostemp, mkstemps and mkostemps

[Szabolcs Nagy <nsz@port70.net>]

* Anthony G. Basile <basile@opensource.dyc.edu> [2013-02-02 13:45:31 -0500]:
> +	/* Null terminate the template before the suffix,
> +	   and save the char for adding back the suffix */
> +	char suffix = template[l];
> +	template[l] = '\0';

if you set only the XXXXXX part in __randname, then the \0 is unnecessary

> +	int fd, retries = 100;
> +	while (retries--) {
> +		if (!*__randname(template)) return -1;

__randname cannot fail, so the check is unnecessary

> +/* This assumes that a check for the
> +   template size has alrady been made */
> +char *__randname(char *template)
> +{
> +	struct timespec ts;
> +	size_t i, l = strlen(template);
> +
> +	/* r is intentially uninialized and 'dirty' */
> +	unsigned long r;
> +

it's undefined behaviour so the compiler is allowed to
completely remove the code of this function

if you seen this kind of code somewhere, that's a critical
bug that should be reported

the original address based entropy source was ok

> +	clock_gettime(CLOCK_REALTIME, &ts);
> +	r += ((uint64_t) ts.tv_nsec << 16) ^ ts.tv_sec;
> +	for (i=1; i<=6; i++, r>>=6)
> +		template[l-i] = __map_letter(r);
> +
> +	return template;
> +}