[php内核bug]动态链接方式编译的扩展, 扩展全局空间dtor导致core dump
author: goosman.lei(雷果国)
blog: http://blog.csdn.net/lgg201
mail: lgg860911@yahoo.com.cn
相关代码可以参考
注册扩展的全局空间代码如下:
#ifdef ZTS
ts_allocate_id(&sample_globals_id, sizeof(zend_sample_globals), (ts_allocate_ctor)ZEND_MODULE_GLOBALS_CTOR_N(sample), (ts_allocate_dtor)ZEND_MODULE_GLOBALS_DTOR_N(sample));
#else
sample_globals_ctor(&sample_globals TSRMLS_CC);
#endif
在ts_allocate_id()函数调用中, 向resource_types_table这个数组中写入了一条记录.
在tsrm_shutdown()的过程中, 将调用注册的dtor回调函数.
但是我这边在按照书上编码完后, 运行测试代码会有coredump.
经过跟踪发现, 在zend_shutdown()的调用过程中, 已经对模块调用了DL_UNLOAD(module->handle); 导致当时注册的句柄(dtor)在执行tsrm_shutdown()时已经不可访问.
同时, 看到标准扩展中的ext/standard/file.c中也有这种注册方式的使用, 不过, 它应该是静态编译所以没有问题. 而我的扩展是编译.so动态链接的.
下面是跟踪zend_shutdown()最终到DL_UNLOAD()的调用路径.
zend_shutdown() => zend_desctroy_modules() => zend_hash_graceful_reverse_destroy() => zend_hash_apply_deleter() => module_destructor() => DL_UNLOAD()
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