php内核宏研究

最近在研究php内核，发现了解各种宏的作用和本质很重要，整理上来便于参考

对这些宏的理解未找到相关官方文档和书籍，只能凭经验和注释来理解其含义，可能会有理解错误的情况，如有错误，万望指正

EG

这个宏用于访问php的全局执行数据结构

php对这个宏的定义是这样的：

/* Executor */
#ifdef ZTS
# define EG(v) TSRMG(executor_globals_id, zend_executor_globals *, v)
#else
# define EG(v) (executor_globals.v)
extern ZEND_API zend_executor_globals executor_globals;
#endif

这应该是一个线程安全的全局执行变量，用于访问 executor_globals变量，该变量结构为：zend_executor_globals

typedef struct _zend_executor_globals zend_executor_globals;

结构具体定义为：

struct _zend_executor_globals {
    zval **return_value_ptr_ptr;

    zval uninitialized_zval;
    zval *uninitialized_zval_ptr;

    zval error_zval;
    zval *error_zval_ptr;

    /* symbol table cache */
    HashTable *symtable_cache[SYMTABLE_CACHE_SIZE];
    HashTable **symtable_cache_limit;
    HashTable **symtable_cache_ptr;

    zend_op **opline_ptr;

    HashTable *active_symbol_table;
    HashTable symbol_table;        /* main symbol table */

    HashTable included_files;    /* files already included */

    JMP_BUF *bailout;

    int error_reporting;
    int orig_error_reporting;
    int exit_status;

    zend_op_array *active_op_array;

    HashTable *function_table;    /* function symbol table */
    HashTable *class_table;        /* class table */
    HashTable *zend_constants;    /* constants table */

    zend_class_entry *scope;
    zend_class_entry *called_scope; /* Scope of the calling class */

    zval *This;

    long precision;

    int ticks_count;

    zend_bool in_execution;
    HashTable *in_autoload;
    zend_function *autoload_func;
    zend_bool full_tables_cleanup;

    /* for extended information support */
    zend_bool no_extensions;

#ifdef ZEND_WIN32
    zend_bool timed_out;
    OSVERSIONINFOEX windows_version_info;
#endif

    HashTable regular_list;
    HashTable persistent_list;

    zend_vm_stack argument_stack;

    int user_error_handler_error_reporting;
    zval *user_error_handler;
    zval *user_exception_handler;
    zend_stack user_error_handlers_error_reporting;
    zend_ptr_stack user_error_handlers;
    zend_ptr_stack user_exception_handlers;

    zend_error_handling_t  error_handling;
    zend_class_entry      *exception_class;

    /* timeout support */
    int timeout_seconds;

    int lambda_count;

    HashTable *ini_directives;
    HashTable *modified_ini_directives;
    zend_ini_entry *error_reporting_ini_entry;                    

    zend_objects_store objects_store;
    zval *exception, *prev_exception;
    zend_op *opline_before_exception;
    zend_op exception_op[3];

    struct _zend_execute_data *current_execute_data;

    struct _zend_module_entry *current_module;

    zend_property_info std_property_info;

    zend_bool active; 

    zend_op *start_op;

    void *saved_fpu_cw_ptr;
#if XPFPA_HAVE_CW
    XPFPA_CW_DATATYPE saved_fpu_cw;
#endif

    void *reserved[ZEND_MAX_RESERVED_RESOURCES];
};

SG

存放全局sapi请求信息，线程安全

BEGIN_EXTERN_C()
#ifdef ZTS
# define SG(v) TSRMG(sapi_globals_id, sapi_globals_struct *, v)
SAPI_API extern int sapi_globals_id;
#else
# define SG(v) (sapi_globals.v)
extern SAPI_API sapi_globals_struct sapi_globals;
#endif

typedef struct _sapi_globals_struct {
    void *server_context;
    sapi_request_info request_info;
    sapi_headers_struct sapi_headers;
    int64_t read_post_bytes;
    unsigned char post_read;
    unsigned char headers_sent;
    struct stat global_stat;
    char *default_mimetype;
    char *default_charset;
    HashTable *rfc1867_uploaded_files;
    long post_max_size;
    int options;
    zend_bool sapi_started;
    double global_request_time;
    HashTable known_post_content_types;
    zval *callback_func;
    zend_fcall_info_cache fci_cache;
    zend_bool callback_run;
} sapi_globals_struct;

PHP_NAMED_FUNCTION

定义一个php内部函数，函数明前不附加前缀，参考下面的ZEND_FUNCTION可以看得更清楚

#define PHP_NAMED_FUNCTION        ZEND_NAMED_FUNCTION

#define ZEND_NAMED_FUNCTION(name)        void name(INTERNAL_FUNCTION_PARAMETERS)

#define INTERNAL_FUNCTION_PARAMETERS int ht, zval *return_value, zval **return_value_ptr, zval *this_ptr, int return_value_used TSRMLS_DC

ZEND_FUNCTION

定义一个php内部函数，函数名附加前缀

#define ZEND_FUNCTION(name)                ZEND_NAMED_FUNCTION(ZEND_FN(name))

#define ZEND_FN(name) zif_##name