php: Fix memory corruption for uwsgi_cache_*

[aszlig]

Ah the joys of variadic arguments in C...

So, when using zend_parse_parameters(), PHP internally loops through the type specifiers and accordingly uses va_arg() to get the corresponding argument.

Since the arguments are expected to be pointers to the corresponding values, the size of them does matter, because PHP simply writes to the corresponding address with a size of size_t.

If we for example pass a pointer to a 32bit integer and PHP writes 64 bits, we have an overflow of 4 bytes.

From README.PARAMETER_PARSING_API in the PHP source tree:

Please note that since version 7 PHP uses zend_long as integer type
and zend_string with size_t as length, so make sure you pass
zend_longs to "l" and size_t to strings length (i.e. for "s" you need
to pass char * and size_t), not the other way round!

Both mistakes might cause memory corruptions and segfaults:

1. char str;
   long str_len; / XXX THIS IS WRONG!! Use size_t instead. */
   zend_parse_parameters(ZEND_NUM_ARGS(), "s", &str, &str_len)

2. int num; /* XXX THIS IS WRONG!! Use zend_long instead. */
   zend_parse_parameters(ZEND_NUM_ARGS(), "l", &num)

To fix this, I changed the types accordingly to use size_t and zend_long if the PHP major version is >= 7.

[aszlig]

@xrmx: Seeing that this issue still persists in version 2.0.20, could you please cherry-pick this to uwsgi-2.0? Alternatively I could open a new pull request based on uwsgi-2.0 if that's preferred in your workflow.

[xrmx]

@aszlig backported here xrmx@a5c1e28 , will merge here once the ci finishes