1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
20 /* Memory handler for a shared memory divided in slot.
24 * @brief Memory Slot Extension Storage Module for Apache
27 * @ingroup APACHE_MODS
32 #include "http_config.h"
34 #include "ap_provider.h"
37 #include "apr_strings.h"
38 #include "apr_pools.h"
40 #include "apr_global_mutex.h"
41 #include "apr_file_io.h"
44 #include <unistd.h> /* for getpid() */
51 #define AP_SLOTMEM_PROVIDER_GROUP "slotmem"
52 #define AP_SLOTMEM_PROVIDER_VERSION 0
54 typedef unsigned int ap_slotmem_type_t;
57 * Values for ap_slotmem_type_t::
59 * AP_SLOTMEM_TYPE_PERSIST: For transitory providers, persist
60 * the data on the file-system
62 * AP_SLOTMEM_TYPE_NOTMPSAFE:
64 * AP_SLOTMEM_TYPE_PREALLOC: Access to slots require they be grabbed 1st
66 #define AP_SLOTMEM_TYPE_PERSIST (1 << 0)
67 #define AP_SLOTMEM_TYPE_NOTMPSAFE (1 << 1)
68 #define AP_SLOTMEM_TYPE_PREGRAB (1 << 2)
70 typedef struct ap_slotmem_instance_t ap_slotmem_instance_t;
73 * callback function used for slotmem.
74 * @param mem is the memory associated with a worker.
75 * @param data is what is passed to slotmem.
76 * @param pool is pool used
77 * @return APR_SUCCESS if all went well
79 typedef apr_status_t ap_slotmem_callback_fn_t(void* mem, void *data, apr_pool_t *pool);
81 struct ap_slotmem_provider_t {
83 * Name of the provider method
87 * call the callback on all worker slots
88 * @param s ap_slotmem_instance_t to use.
89 * @param funct callback function to call for each element.
90 * @param data parameter for the callback function.
91 * @param pool is pool used
92 * @return APR_SUCCESS if all went well
94 apr_status_t (* doall)(ap_slotmem_instance_t *s, ap_slotmem_callback_fn_t *func, void *data, apr_pool_t *pool);
96 * create a new slotmem with each item size is item_size.
97 * This would create shared memory, basically.
98 * @param name is a key used for debugging and in mod_status output or allow another process to share this space.
99 * @param item_size size of each item
100 * @param item_num number of item to create.
101 * @param type type of slotmem.
102 * @param pool is pool used
103 * @return APR_SUCCESS if all went well
105 apr_status_t (* create)(ap_slotmem_instance_t **new, const char *name, apr_size_t item_size, unsigned int item_num, ap_slotmem_type_t type, apr_pool_t *pool);
107 * attach to an existing slotmem.
108 * This would attach to shared memory, basically.
109 * @param name is a key used for debugging and in mod_status output or allow another process to share this space.
110 * @param item_size size of each item
111 * @param item_num max number of item.
112 * @param pool is pool to memory allocate.
113 * @return APR_SUCCESS if all went well
115 apr_status_t (* attach)(ap_slotmem_instance_t **new, const char *name, apr_size_t *item_size, unsigned int *item_num, apr_pool_t *pool);
117 * get the memory ptr associated with this worker slot.
118 * @param s ap_slotmem_instance_t to use.
119 * @param item_id item to return for 0 to item_num
120 * @param mem address to store the pointer to the slot
121 * @return APR_SUCCESS if all went well
123 apr_status_t (* dptr)(ap_slotmem_instance_t *s, unsigned int item_id, void**mem);
125 * get/read the data associated with this worker slot.
126 * @param s ap_slotmem_instance_t to use.
127 * @param item_id item to return for 0 to item_num
128 * @param dest address to store the data
129 * @param dest_len length of dataset to retrieve
130 * @return APR_SUCCESS if all went well
132 apr_status_t (* get)(ap_slotmem_instance_t *s, unsigned int item_id, unsigned char *dest, apr_size_t dest_len);
134 * put/write the data associated with this worker slot.
135 * @param s ap_slotmem_instance_t to use.
136 * @param item_id item to return for 0 to item_num
137 * @param src address of the data to store in the slot
138 * @param src_len length of dataset to store in the slot
139 * @return APR_SUCCESS if all went well
141 apr_status_t (* put)(ap_slotmem_instance_t *slot, unsigned int item_id, unsigned char *src, apr_size_t src_len);
143 * return number of slots allocated for this entry.
144 * @param s ap_slotmem_instance_t to use.
145 * @return number of slots
147 unsigned int (* num_slots)(ap_slotmem_instance_t *s);
149 * return number of free (not used) slots allocated for this entry.
150 * Valid for slots which are AP_SLOTMEM_TYPE_PREGRAB as well as
151 * any which use get/release.
152 * @param s ap_slotmem_instance_t to use.
153 * @return number of slots
155 unsigned int (* num_free_slots)(ap_slotmem_instance_t *s);
157 * return slot size allocated for this entry.
158 * @param s ap_slotmem_instance_t to use.
159 * @return size of slot
161 apr_size_t (* slot_size)(ap_slotmem_instance_t *s);
163 * grab (or alloc) a free slot
164 * @param s ap_slotmem_instance_t to use.
165 * @param item_id ptr to the available slot id and marked as in-use
166 * @return APR_SUCCESS if all went well
168 apr_status_t (* grab)(ap_slotmem_instance_t *s, unsigned int *item_id);
170 * release (or free) the slot associated with this item_id
171 * @param s ap_slotmem_instance_t to use.
172 * @param item_id slot id to free and mark as no longer in-use
173 * @return APR_SUCCESS if all went well
175 apr_status_t (* release)(ap_slotmem_instance_t *s, unsigned int item_id);
178 typedef struct ap_slotmem_provider_t ap_slotmem_provider_t;