Description:
------------
stream_wrapper_register() crashes when it gets a very long class name string passed. A lot of (all?) other functions which accept a class name as an argument have the same problem (for example: is_subclass_of(), get_class_vars(), class_exists(), property_exists(), get_class_methods()...)
This was originally from http://www.securityfocus.com/archive/1/483644/30/0/threaded (which only mentions stream_wrapper_register)

I guess the fix has to be somewhere in zend_str_tolower_copy(), but I don't quite understand what is actually causing the segfault.

Reproduce code:
---------------
php -r 'var_dump(stream_wrapper_register("something", str_repeat("a", 10000000)));'
php -r 'var_dump(class_exists(str_repeat("a", 10000000)));'

Expected result:
----------------
bool(false)
bool(false)

Actual result:
--------------
Program received signal SIGSEGV, Segmentation fault.
0x0000000000553367 in zend_lookup_class_ex (name=0x2b105681b070 'a' <repeats 200 times>..., 
    name_length=10000000, use_autoload=1, ce=0x7fff552d8910)
    at /tmp/php-5.2.5.build/Zend/zend_execute_API.c:1046
1046            zend_str_tolower_copy(lc_name, name, name_length);
(gdb) bt
#0  0x0000000000553367 in zend_lookup_class_ex (
    name=0x2b105681b070 'a' <repeats 200 times>..., name_length=10000000, use_autoload=1, 
    ce=0x7fff552d8910) at /tmp/php-5.2.5.build/Zend/zend_execute_API.c:1046
#1  0x000000000055373c in zend_lookup_class (name=0x2b105681b070 'a' <repeats 200 times>..., 
    name_length=10000000, ce=0x7fff552d8910)
    at /tmp/php-5.2.5.build/Zend/zend_execute_API.c:1128
#2  0x00000000005753a9 in zif_class_exists (ht=1, return_value=0x9569c0, return_value_ptr=0x0, 
    this_ptr=0x0, return_value_used=1)
    at /tmp/php-5.2.5.build/Zend/zend_builtin_functions.c:1032
#3  0x0000000000589b19 in zend_do_fcall_common_helper_SPEC (execute_data=0x7fff552d8b10)
    at /tmp/php-5.2.5.build/Zend/zend_vm_execute.h:200
#4  0x000000000058fc7d in ZEND_DO_FCALL_SPEC_CONST_HANDLER (execute_data=0x7fff552d8b10)
    at /tmp/php-5.2.5.build/Zend/zend_vm_execute.h:1681
#5  0x00000000005895ba in execute (op_array=0x957648)
    at /tmp/php-5.2.5.build/Zend/zend_vm_execute.h:92
#6  0x00000000005538ce in zend_eval_string (
    str=0x7fff552da0fb "var_dump(class_exists(str_repeat(\"a\", 10000000)));", retval_ptr=0x0, 
    string_name=0x67a6f4 "Command line code")
    at /tmp/php-5.2.5.build/Zend/zend_execute_API.c:1171
#7  0x0000000000553a4b in zend_eval_string_ex (
    str=0x7fff552da0fb "var_dump(class_exists(str_repeat(\"a\", 10000000)));", retval_ptr=0x0, 
    string_name=0x67a6f4 "Command line code", handle_exceptions=1)
    at /tmp/php-5.2.5.build/Zend/zend_execute_API.c:1205
#8  0x00000000005e37c3 in main (argc=3, argv=0x7fff552d90a8)
    at /tmp/php-5.2.5.build/sapi/cli/php_cli.c:1179