# Class constants ... possible?

- Thread: https://externals.io/message/13058
- Original archive: https://news-web.php.net/php.internals/13058
- Started by Robert Silva on 2004-09-28T19:01:00+00:00
- Messages: 2
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## #13058 — Robert Silva — 2004-09-28T19:01:00+00:00

URL: https://externals.io/message/13058#13058

After 3 days tracing this thing, I found the problem. Any suggestions?

Im trying to define a class constant by allocating a zval str using
ALLOC_ZVAL in PHP_MINIT for my extension. This class constant is applied to
the class and works as expected. The problem comes during shutdown. In
php_request_shutdown --> shutdown_memory_manager, it detects the ZVAL that
the constant was stored in as a "leak" and frees the zval. This causes PHP
to crash during tsrm_shutdown when it starts destroying classes.

Is it expected for a variable allocated during module init to be freed
during request shutdown?

Below is the trace of the class destruction (after the memory manager
already freed my zval in the class_constants ht.

The first line here is freeing the zval associated with the constants key in
the class_entry->constants_table (which has already been freed).

php5ts_debug.dll!_zval_internal_ptr_dtor(_zval_struct * *
php5ts_debug.dll!_zval_internal_ptr_dtor_wrapper(_zval_struct * *
php5ts_debug.dll!zend_hash_destroy(_hashtable * ht=0x009827cc)  Line 521 +
php5ts_debug.dll!destroy_zend_class(_zend_class_entry * * pce=0x009e3de4)
php5ts_debug.dll!zend_hash_destroy(_hashtable * ht=0x009e32d8)  Line 521 +
php5ts_debug.dll!compiler_globals_dtor(_zend_compiler_globals *
php5ts_debug.dll!tsrm_shutdown()  Line 164 + 0x21	C
php.exe!main(int argc=4, char * * argv=0x00902508)  Line 1056 + 0x8	C
php.exe!mainCRTStartup()  Line 398 + 0x11	C
kernel32.dll!77e814c7() 	

And here is my the call stack when it frees the memory:
e:\php5\php5cvs\php5\ext\bfl\bfl_system.c(332) :  Freeing 0x00920728 (16
bytes), script=test.php

php5ts_debug.dll!shutdown_memory_manager(int silent=0, int full_shutdown=0,
php5ts_debug.dll!php_request_shutdown(void * dummy=0x00000000)  Line 1227 +
php.exe!main(int argc=4, char * * argv=0x00902508)  Line 1046 + 0xa	C
php.exe!mainCRTStartup()  Line 398 + 0x11	C
kernel32.dll!77e814c7()


So is it possible to define a class constant during MINIT? If so how. Use a
module global?

Thanks
 Bob

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## #13061 — Marcus Boerger — 2004-09-28T21:32:32+00:00

URL: https://externals.io/message/13058#13061 · In reply to: #13058

Hello Robert,

Tuesday, September 28, 2004, 9:01:00 PM, you wrote:

> After 3 days tracing this thing, I found the problem. Any suggestions?

> Im trying to define a class constant by allocating a zval str using
> ALLOC_ZVAL in PHP_MINIT for my extension.

You cannot use ALLOC_ZVAL during PHP_MINIT.

If you look at zend_declare_property*() you'll find out how to declare your
consts. Maybe we could provide zend_declare_const*() inside the engine.

regards
marcus

> This class constant is applied to
> the class and works as expected. The problem comes during shutdown. In
> php_request_shutdown --> shutdown_memory_manager, it detects the ZVAL that
> the constant was stored in as a "leak" and frees the zval. This causes PHP
> to crash during tsrm_shutdown when it starts destroying classes.

> Is it expected for a variable allocated during module init to be freed
> during request shutdown?

> Below is the trace of the class destruction (after the memory manager
> already freed my zval in the class_constants ht.

> The first line here is freeing the zval associated with the constants key in
> the class_entry->constants_table (which has already been freed).

> php5ts_debug.dll!_zval_internal_ptr_dtor(_zval_struct * *
> php5ts_debug.dll!_zval_internal_ptr_dtor_wrapper(_zval_struct * *
> php5ts_debug.dll!zend_hash_destroy(_hashtable * ht=0x009827cc)  Line 521 +
> php5ts_debug.dll!destroy_zend_class(_zend_class_entry * * pce=0x009e3de4)
> php5ts_debug.dll!zend_hash_destroy(_hashtable * ht=0x009e32d8)  Line 521 +
> php5ts_debug.dll!compiler_globals_dtor(_zend_compiler_globals *
> php5ts_debug.dll!tsrm_shutdown()  Line 164 + 0x21	C
> php.exe!main(int argc=4, char * * argv=0x00902508)  Line 1056 + 0x8	C
> php.exe!mainCRTStartup()  Line 398 + 0x11	C
> kernel32.dll!77e814c7() 	

> And here is my the call stack when it frees the memory:
> e:\php5\php5cvs\php5\ext\bfl\bfl_system.c(332) :  Freeing 0x00920728 (16
> bytes), script=test.php

> php5ts_debug.dll!shutdown_memory_manager(int silent=0, int full_shutdown=0,
> php5ts_debug.dll!php_request_shutdown(void * dummy=0x00000000)  Line 1227 +
> php.exe!main(int argc=4, char * * argv=0x00902508)  Line 1046 + 0xa	C
> php.exe!mainCRTStartup()  Line 398 + 0x11	C
> kernel32.dll!77e814c7()


> So is it possible to define a class constant during MINIT? If so how. Use a
> module global?

> Thanks
>  Bob




-- 
Best regards,
 Marcus                            mailto:helly@php.net