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      1 /*
      2  * services/modstack.h - stack of modules
      3  *
      4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
      5  *
      6  * This software is open source.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * Redistributions of source code must retain the above copyright notice,
     13  * this list of conditions and the following disclaimer.
     14  *
     15  * Redistributions in binary form must reproduce the above copyright notice,
     16  * this list of conditions and the following disclaimer in the documentation
     17  * and/or other materials provided with the distribution.
     18  *
     19  * Neither the name of the NLNET LABS nor the names of its contributors may
     20  * be used to endorse or promote products derived from this software without
     21  * specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
     29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 /**
     37  * \file
     38  *
     39  * This file contains functions to help maintain a stack of modules.
     40  */
     41 
     42 #ifndef SERVICES_MODSTACK_H
     43 #define SERVICES_MODSTACK_H
     44 struct module_func_block;
     45 struct module_env;
     46 
     47 /**
     48  * Stack of modules.
     49  */
     50 struct module_stack {
     51 	/** the number of modules */
     52 	int num;
     53 	/** the module callbacks, array of num_modules length (ref only) */
     54 	struct module_func_block** mod;
     55 };
     56 
     57 /**
     58  * Init a stack of modules
     59  * @param stack: initialised as empty.
     60  */
     61 void modstack_init(struct module_stack* stack);
     62 
     63 /**
     64  * Free the stack of modules
     65  * @param stack: stack that frees up memory.
     66  */
     67 void modstack_free(struct module_stack* stack);
     68 
     69 /**
     70  * Initialises modules and assigns ids. Calls module_startup().
     71  * @param stack: Expected empty, filled according to module_conf
     72  * @param module_conf: string what modules to initialize
     73  * @param env: module environment which is inited by the modules.
     74  *	environment should have a superalloc, cfg,
     75  * @return on false a module init failed.
     76  */
     77 int modstack_call_startup(struct module_stack* stack, const char* module_conf,
     78 	struct module_env* env);
     79 
     80 /**
     81  * Read config file module settings and set up the modfunc block
     82  * @param stack: the stack of modules (empty before call).
     83  * @param module_conf: string what modules to insert.
     84  * @return false on error
     85  */
     86 int modstack_config(struct module_stack* stack, const char* module_conf);
     87 
     88 /**
     89  * Get funcblock for module name
     90  * @param str: string with module name. Advanced to next value on success.
     91  *	The string is assumed whitespace separated list of module names.
     92  * @return funcblock or NULL on error.
     93  */
     94 struct module_func_block* module_factory(const char** str);
     95 
     96 /**
     97  * Get list of modules available.
     98  * @return list of modules available. Static strings, ends with NULL.
     99  */
    100 const char** module_list_avail(void);
    101 
    102 /**
    103  * Init modules. Calls module_init().
    104  * @param stack: It is modstack_setupped().
    105  * @param module_conf: module ordering to check against the ordering in stack.
    106  *	fails on changed ordering.
    107  * @param env: module environment which is inited by the modules.
    108  *	environment should have a superalloc, cfg,
    109  *	env.need_to_validate is set by the modules.
    110  * @return on false a module init failed.
    111  */
    112 int modstack_call_init(struct module_stack* stack, const char* module_conf,
    113 	struct module_env* env);
    114 
    115 /**
    116  * Deinit the modules.
    117  * @param stack: made empty.
    118  * @param env: module env for module deinit() calls.
    119  */
    120 void modstack_call_deinit(struct module_stack* stack, struct module_env* env);
    121 
    122 /**
    123  * Destartup the modules, close, delete.
    124  * @param stack: made empty.
    125  * @param env: module env for module destartup() calls.
    126  */
    127 void modstack_call_destartup(struct module_stack* stack, struct module_env* env);
    128 
    129 /**
    130  * Find index of module by name.
    131  * @param stack: to look in
    132  * @param name: the name to look for
    133  * @return -1 on failure, otherwise index number.
    134  */
    135 int modstack_find(struct module_stack* stack, const char* name);
    136 
    137 /** fetch memory for a module by name, returns 0 if module not there */
    138 size_t mod_get_mem(struct module_env* env, const char* name);
    139 
    140 #endif /* SERVICES_MODSTACK_H */
    141