Apache 的hook 一览

本章的重要内容： 关于hook的调用顺序 钩子函数的调用顺序是：「设定的初期化」「进程的初期化」「连接」「请求」 关于RUN_ALL，RUN_FIRST RUN_FIRST  类型的hook 是：被调用的 hook函数的返回值为 OK 或者是 DECLINE（出错）时，后面的hook是不被执行的。
RUN_ALL 类型的hook 是：被调用的 hook函数的返回值不为DECLINE（出错）时，已经加载的hook将被全部执行。 关于hook 登録函数 ap_hook_xxx() 的参数 ap_hook_xxx() 的参数全部相同．具体的请参照下面．

Index

設定初期化
RUN_ALL	ap_hook_pre_config()
RUN_ALL	ap_hook_open_logs()
RUN_ALL	ap_hook_post_config()
VOID	ap_hook_optional_fn_retrieve()
进程初期化
RUN_ALL	ap_hook_pre_mpm()
VOID	ap_hook_child_init()
连接
RUN_FIRST	ap_hook_create_connection()
RUN_ALL	ap_hook_pre_connection()
RUN_FIRST	ap_hook_process_connection()
请求（Request）
RUN_ALL	ap_hook_create_request()
RUN_ALL	ap_hook_post_read_request()
RUN_FIRST	ap_hook_quick_handler()
RUN_FIRST	ap_hook_translate_name()
RUN_FIRST	ap_hook_map_to_storage()
RUN_ALL	ap_hook_header_parser()
RUN_ALL	ap_hook_access_checker()
RUN_FIRST	ap_hook_check_user_id()
RUN_FIRST	ap_hook_auth_checker()
RUN_FIRST	ap_hook_type_checker()
RUN_ALL	ap_hook_fixups()
VOID	ap_hook_insert_filter()
RUN_FIRST	ap_hook_handler()
RUN_ALL	ap_hook_log_transaction()
出错 ERRor
VOID	ap_hook_insert_error_filter()
VOID	ap_hook_error_log()
必要時
RUN_FIRST	ap_hook_default_port()
RUN_FIRST	ap_hook_http_method()
随时被调用?
RUN_ALL	ap_hook_fatal_exception()
RUN_ALL	ap_hook_get_mgmt_items()
RUN_FIRST	ap_hook_uexec_identity()

説明

ap_hook_pre_config()

RUN_ALL

Run the pre_config function for each module

int x_pre_config(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *ptemp)
return	OK or DECLINED on success anything else is a error
pconf	The config pool
plog	The logging streams pool
ptemp	The temporary pool

ap_hook_open_logs()

RUN_ALL

Run the open_logs functions for each module

int x_open_logs(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
return	OK or DECLINED on success anything else is a error
pconf	The config pool
plog	The logging streams pool
ptemp	The temporary pool
s	The list of server_recs

ap_hook_post_config()

RUN_ALL

Run the post_config function for each module

int x_post_config(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
return	OK or DECLINED on success anything else is a error
pconf	The config pool
plog	The logging streams pool
ptemp	The temporary pool
s	The list of server_recs

ap_hook_optional_fn_retrieve()

Retrieve the optional functions for each module. This is run immediately before the server starts. Optional functions should be registered during the hook registration phase.

void x_optional_fn_retrieve(void)

ap_hook_pre_mpm()

RUN_ALL

Hook for post scoreboard creation, pre mpm.

int x_pre_mpm(apr_pool_t *p, ap_scoreboard_e sb_type)
return	OK or DECLINE on success; anything else is a error
p	Apache pool to allocate from.
sb_type

ap_hook_child_init()

Run the child_init functions for each module

void x_child_init(apr_pool_t *pchild, server_rec *s)
pchild	The child pool
s	The list of server_recs in this server

ap_hook_create_connection()

RUN_FIRST

create_connection is a RUN_FIRST hook which allows modules to create connections. In general, you should not install filters with the create_connection hook. If you require vhost configuration information to make filter installation decisions, you must use the pre_connection or install_network_transport hook. This hook should close the connection if it encounters a fatal error condition.

conn_rec * x_create_connection(apr_pool_t *p, server_rec *server, apr_socket_t *csd, long conn_id, void *sbh, apr_bucket_alloc_t *alloc)
return	An allocated connection record or NULL.
server
p	The pool from which to allocate the connection record
csd	The socket that has been accepted
conn_id	A unique identifier for this connection. The ID only needs to be unique at that time, not forever.
sbh	A handle to scoreboard information for this connection.
alloc

ap_hook_pre_connection()

RUN_ALL

This hook gives protocol modules an opportunity to set everything up before calling the protocol handler. All pre-connection hooks are run until one returns something other than ok or decline
Apache の付属文書によれば，accept()直後に呼ばれる

int x_pre_connection(conn_rec *c, void *csd)
return	OK or DECLINED
c	The connection on which the request has been received.
csd	The mechanism on which this connection is to be read. Most times this will be a socket, but it is up to the module that accepts the request to determine the exact type.

ap_hook_process_connection()

RUN_FIRST

This hook implements different protocols. After a connection has been established, the protocol module must read and serve the request. This function does that for each protocol module. The first protocol module to handle the request is the last module run.

int x_process_connection(conn_rec *c)
return	OK or DECLINED
c	The connection on which the request has been received.

ap_hook_create_request()

RUN_ALL

Gives modules a chance to create their request_config entry when the request is created.

int x_create_request(request_rec *r)
return	OK or DECLINED
r	The current request

ap_hook_post_read_request()

RUN_ALL

This hook allows modules to affect the request immediately after the request has been read, and before any other phases have been processes. This allows modules to make decisions based upon the input header fields

int x_post_read_request(request_rec *r)
return	OK or DECLINED
r	The current request

ap_hook_quick_handler()

RUN_FIRST

Run the quick handler functions for each module. The quick_handler is run before any other requests hooks are called (location_walk, directory_walk, access checking, et. al.). This hook was added to provide a quick way to serve content from a URI keyed cache.
Apache の付属文書によれば，キャッシュモジュールが使用している．

int x_quick_handler(request_rec *r, int lookup_uri)
r	The request_rec
lookup_uri	Controls whether the caller actually wants content or not. lookup is set when the quick_handler is called out of ap_sub_req_lookup_uri()

ap_hook_translate_name()

RUN_FIRST

This hook allow modules an opportunity to translate the URI into an actual filename. If no modules do anything special, the server's default rules will be followed.

int x_translate_name(request_rec *r)
return	OK, DECLINED, or HTTP_...
r	The current request

ap_hook_map_to_storage()

RUN_FIRST

This hook allow modules to set the per_dir_config based on their own context (such as sections) and responds to contextless requests such as TRACE that need no security or filesystem mapping. based on the filesystem.

int x_map_to_storage(request_rec *r)
return	DONE (or HTTP_) if this contextless request was just fulfilled (such as TRACE), OK if this is not a file, and DECLINED if this is a file. The core map_to_storage (HOOK_RUN_REALLY_LAST) will directory_walk and file_walk the r->filename.
r	The current request

ap_hook_header_parser()

RUN_ALL

Run the header parser functions for each module

int x_header_parser(request_rec *r)
return	OK or DECLINED
r	The current request

ap_hook_access_checker()

RUN_ALL

This hook is used to apply additional access control to this resource. It runs *before* a user is authenticated, so this hook is really to apply additional restrictions independent of a user. It also runs independent of 'Require' directive usage.

int x_access_checker(request_rec *r)
return	OK, DECLINED, or HTTP_...
r	the current request

ap_hook_check_user_id()

RUN_FIRST

This hook is used to analyze the request headers, authenticate the user, and set the user information in the request record (r->user and r->ap_auth_type). This hook is only run when Apache determines that authentication/authorization is required for this resource (as determined by the 'Require' directive). It runs after the access_checker hook, and before the auth_checker hook.

int x_check_user_id(request_rec *r)
return	OK, DECLINED, or HTTP_...
r	The current request

ap_hook_auth_checker()

RUN_FIRST

This hook is used to check to see if the resource being requested is available for the authenticated user (r->user and r->ap_auth_type). It runs after the access_checker and check_user_id hooks. Note that it will *only* be called if Apache determines that access control has been applied to this resource (through a 'Require' directive).

int x_auth_checker(request_rec *r)
return	OK, DECLINED, or HTTP_...
r	the current request

ap_hook_type_checker()

RUN_FIRST

This routine is called to determine and/or set the various document type information bits, like Content-type (via r->content_type), language, et cetera.

int x_type_checker(request_rec *r)
return	OK, DECLINED, or HTTP_...
r	the current request

ap_hook_fixups()

RUN_ALL

Allows modules to perform module-specific fixing of header fields. This is invoked just before any content-handler

int x_fixups(request_rec *r)
return	OK, DECLINED, or HTTP_...
r	The current request

ap_hook_insert_filter()

This hook allows modules to insert filters for the current request

void x_insert_filter(request_rec *r)
r	the current request

ap_hook_handler()

RUN_FIRST

Run the handler functions for each module non-wildcard handlers should HOOK_MIDDLE, wildcard HOOK_LAST

int x_handler(request_rec *r)
r	The request_rec

ap_hook_log_transaction()

RUN_ALL

This hook allows modules to perform any module-specific logging activities over and above the normal server things.

int x_log_transaction(request_rec *r)
return	OK, DECLINED, or HTTP_...
r	The current request

ap_hook_insert_error_filter()

This hook allows modules to insert filters for the current error response

void x_insert_error_filter(request_rec *r)
r	the current request

ap_hook_error_log()

void x_error_log(const char *file,
                 int line,
                 int level,
                 apr_status_t status,
                 const server_rec *s,
                 const request_rec *r,
                 apr_pool_t *pool,
                 const char *errstr)

ap_hook_default_port()

RUN_FIRST

Return the default port from the current request

apr_port_t x_default_port(const request_rec *r)
return	The current port
r	The current request

ap_hook_http_method()

RUN_FIRST

This hook allows modules to retrieve the http method from a request. This allows Apache modules to easily extend the methods that Apache understands
ここで言う"method" は scheme の間違いのようです．実際，Apache 2.2 では ap_hook_http_scheme() に変更されています．

const char * x_http_method(const request_rec *r)
return	The http method from the request
r	The current request

ap_hook_fatal_exception()	RUN_ALL
int x_fatal_exception(ap_exception_info_t *ei)

ap_hook_get_mgmt_items()

RUN_ALL

This hook provdes a way for modules to provide metrics/statistics about their operational status.

int x_get_mgmt_items(apr_pool_t *p, const char * val, apr_hash_t *ht)
p	A pool to use to create entries in the hash table
val	The name of the parameter(s) that is wanted. This is tree-structured would be in the form ('*' is all the tree, 'module.*' all of the module , 'module.foo.*', or 'module.foo.bar' )
ht	The hash table to store the results. Keys are item names, and the values point to ap_mgmt_item_t structures.

ap_hook_get_suexec_identity()	RUN_FIRST
ap_unix_identity_t * x_get_suexec_identity(const request_rec *r)