Initial Commit

database/apache/include/mod_watchdog.h

@@ -0,0 +1,213 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef MOD_WATCHDOG_H
+#define MOD_WATCHDOG_H
+
+/**
+ * @file  mod_watchdog.h
+ * @brief Watchdog module for Apache
+ *
+ * @defgroup MOD_WATCHDOG mod_watchdog
+ * @ingroup  APACHE_MODS
+ * @{
+ */
+
+#include "httpd.h"
+#include "http_config.h"
+#include "http_log.h"
+#include "ap_provider.h"
+
+#include "apr.h"
+#include "apr_strings.h"
+#include "apr_pools.h"
+#include "apr_shm.h"
+#include "apr_hash.h"
+#include "apr_hooks.h"
+#include "apr_optional.h"
+#include "apr_file_io.h"
+#include "apr_time.h"
+#include "apr_thread_proc.h"
+#include "apr_global_mutex.h"
+#include "apr_thread_mutex.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Default singleton watchdog instance name.
+ * Singleton watchdog is protected by mutex and
+ * guaranteed to be run inside a single child process
+ * at any time.
+ */
+#define AP_WATCHDOG_SINGLETON       "_singleton_"
+
+/**
+ * Default watchdog instance name
+ */
+#define AP_WATCHDOG_DEFAULT         "_default_"
+
+/**
+ * Default Watchdog interval
+ */
+#define AP_WD_TM_INTERVAL           APR_TIME_C(1000000)  /* 1 second     */
+
+/**
+ * Watchdog thread timer resolution
+ */
+#define AP_WD_TM_SLICE              APR_TIME_C(100000)   /* 100 ms       */
+
+/* State values for callback */
+#define AP_WATCHDOG_STATE_STARTING  1
+#define AP_WATCHDOG_STATE_RUNNING   2
+#define AP_WATCHDOG_STATE_STOPPING  3
+
+typedef struct ap_watchdog_t ap_watchdog_t;
+
+/* Create a set of AP_WD_DECLARE(type), AP_WD_DECLARE_NONSTD(type) and
+ * AP_WD_DECLARE_DATA with appropriate export and import tags for the platform
+ */
+#if !defined(AP_WD_DECLARE)
+#if !defined(WIN32)
+#define AP_WD_DECLARE(type)            type
+#define AP_WD_DECLARE_NONSTD(type)     type
+#define AP_WD_DECLARE_DATA
+#elif defined(AP_WD_DECLARE_STATIC)
+#define AP_WD_DECLARE(type)            type __stdcall
+#define AP_WD_DECLARE_NONSTD(type)     type
+#define AP_WD_DECLARE_DATA
+#elif defined(AP_WD_DECLARE_EXPORT)
+#define AP_WD_DECLARE(type)            __declspec(dllexport) type __stdcall
+#define AP_WD_DECLARE_NONSTD(type)     __declspec(dllexport) type
+#define AP_WD_DECLARE_DATA             __declspec(dllexport)
+#else
+#define AP_WD_DECLARE(type)            __declspec(dllimport) type __stdcall
+#define AP_WD_DECLARE_NONSTD(type)     __declspec(dllimport) type
+#define AP_WD_DECLARE_DATA             __declspec(dllimport)
+#endif
+#endif
+
+/**
+ * Callback function used for watchdog.
+ * @param state Watchdog state function. See @p AP_WATCHDOG_STATE_ .
+ * @param data is what was passed to @p ap_watchdog_register_callback function.
+ * @param pool Temporary callback pool destroyed after the call.
+ * @return APR_SUCCESS to continue calling this callback.
+ */
+typedef apr_status_t ap_watchdog_callback_fn_t(int state, void *data,
+                                               apr_pool_t *pool);
+
+/**
+ * Get watchdog instance.
+ * @param watchdog Storage for watchdog instance.
+ * @param name Watchdog name.
+ * @param parent Non-zero to get the parent process watchdog instance.
+ * @param singleton Non-zero to get the singleton watchdog instance.
+ * @param p The pool to use.
+ * @return APR_SUCCESS if all went well
+ * @remark Use @p AP_WATCHDOG_DEFAULT to get default watchdog instance.
+ *         If separate watchdog thread is needed provide unique name
+ *         and function will create a new watchdog instance.
+ *         Note that default client process watchdog works in singleton mode.
+ */
+APR_DECLARE_OPTIONAL_FN(apr_status_t, ap_watchdog_get_instance,
+                        (ap_watchdog_t **watchdog, const char *name, int parent,
+                         int singleton, apr_pool_t *p));
+
+/**
+ * Register watchdog callback.
+ * @param watchdog Watchdog to use
+ * @param interval Interval on which the callback function will execute.
+ * @param callback  The function to call on watchdog event.
+ * @param data The data to pass to the callback function.
+ * @return APR_SUCCESS if all went well. APR_EEXIST if already registered.
+ */
+APR_DECLARE_OPTIONAL_FN(apr_status_t, ap_watchdog_register_callback,
+                        (ap_watchdog_t *watchdog, apr_interval_time_t interval,
+                         const void *data, ap_watchdog_callback_fn_t *callback));
+
+/**
+ * Update registered watchdog callback interval.
+ * @param w Watchdog to use
+ * @param interval New interval on which the callback function will execute.
+ * @param callback  The function to call on watchdog event.
+ * @param data The data to pass to the callback function.
+ * @return APR_SUCCESS if all went well. APR_EOF if callback was not found.
+ */
+APR_DECLARE_OPTIONAL_FN(apr_status_t, ap_watchdog_set_callback_interval,
+                        (ap_watchdog_t *w, apr_interval_time_t interval,
+                         const void *data, ap_watchdog_callback_fn_t *callback));
+
+/**
+ * Watchdog require hook.
+ * @param s The server record
+ * @param name Watchdog name.
+ * @param parent Non-zero to indicate the parent process watchdog mode.
+ * @param singleton Non-zero to indicate the singleton watchdog mode.
+ * @return OK to enable notifications from this watchdog, DECLINED otherwise.
+ * @remark This is called in post config phase for all watchdog instances
+ *         that have no callbacks registered. Modules using this hook
+ *         should ensure that their post_config hook is called after watchdog
+ *         post_config.
+ */
+APR_DECLARE_EXTERNAL_HOOK(ap, AP_WD, int, watchdog_need, (server_rec *s,
+                          const char *name,
+                          int parent, int singleton))
+
+
+/**
+ * Watchdog initialize hook.
+ * It is called after the watchdog thread is initialized.
+ * @param s The server record
+ * @param name Watchdog name.
+ * @param pool The pool used to create the watchdog.
+ */
+APR_DECLARE_EXTERNAL_HOOK(ap, AP_WD, int, watchdog_init, (
+                          server_rec *s,
+                          const char *name,
+                          apr_pool_t *pool))
+
+/**
+ * Watchdog terminate hook.
+ * It is called when the watchdog thread is terminated.
+ * @param s The server record
+ * @param name Watchdog name.
+ * @param pool The pool used to create the watchdog.
+ */
+APR_DECLARE_EXTERNAL_HOOK(ap, AP_WD, int, watchdog_exit, (
+                          server_rec *s,
+                          const char *name,
+                          apr_pool_t *pool))
+
+/**
+ * Fixed interval watchdog hook.
+ * It is called regularly on @p AP_WD_TM_INTERVAL interval.
+ * @param s The server record
+ * @param name Watchdog name.
+ * @param pool Temporary pool destroyed after the call.
+ */
+APR_DECLARE_EXTERNAL_HOOK(ap, AP_WD, int, watchdog_step, (
+                          server_rec *s,
+                          const char *name,
+                          apr_pool_t *pool))
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MOD_WATCHDOG_H */
+/** @} */