255 lines
		
	
	
		
			8.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			255 lines
		
	
	
		
			8.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| #pragma once
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| /*
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|  * Copyright (c) 2016 MariaDB Corporation Ab
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|  *
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|  * Use of this software is governed by the Business Source License included
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|  * in the LICENSE.TXT file and at www.mariadb.com/bsl.
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|  *
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|  * Change Date: 2019-07-01
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|  *
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|  * On the date above, in accordance with the Business Source License, use
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|  * of this software will be governed by version 2 or later of the General
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|  * Public License.
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|  */
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| 
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| /**
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|  * @file module_command.h Module driven commands
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|  *
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|  * This header describes the structures and functions used to register new
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|  * functions for modules. It allows modules to introduce custom commands that
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|  * are registered into a module specific domain. These commands can then be
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|  * accessed from multiple different client interfaces without implementing the
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|  * same functionality again.
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|  */
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| 
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| #include <maxscale/cdefs.h>
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| #include <maxscale/dcb.h>
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| #include <maxscale/filter.h>
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| #include <maxscale/monitor.h>
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| #include <maxscale/server.h>
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| #include <maxscale/service.h>
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| #include <maxscale/session.h>
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| 
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| MXS_BEGIN_DECLS
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| 
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| /**
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|  * The argument type
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|  *
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|  * First 8 bits of @c value are reserved for argument type, bits 9 through
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|  * 32 are reserved for argument options and bits 33 through 64 are reserved
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|  * for future use.
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|  *
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|  * @c description should be a human-readable description of the argument.
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|  */
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| typedef struct
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| {
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|     uint64_t    type;  /**< The argument type */
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|     const char *description; /**< The argument description */
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| } modulecmd_arg_type_t;
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| 
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| /**
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|  * Argument types for the registered functions, the first 8 bits of
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|  * the modulecmd_arg_type_t type's @c value member. An argument can be of
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|  * only one type.
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|  */
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| #define MODULECMD_ARG_NONE        0 /**< Empty argument */
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| #define MODULECMD_ARG_STRING      1 /**< String */
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| #define MODULECMD_ARG_BOOLEAN     2 /**< Boolean value */
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| #define MODULECMD_ARG_SERVICE     3 /**< Service name */
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| #define MODULECMD_ARG_SERVER      4 /**< Server name */
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| #define MODULECMD_ARG_SESSION     5 /**< SESSION pointer in string format */
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| #define MODULECMD_ARG_SESSION_PTR 6 /**< Raw SESSION pointer */
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| #define MODULECMD_ARG_DCB         7 /**< DCB pointer in string format*/
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| #define MODULECMD_ARG_DCB_PTR     8 /**< Raw DCB pointer*/
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| #define MODULECMD_ARG_MONITOR     9 /**< Monitor name */
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| #define MODULECMD_ARG_FILTER      10 /**< Filter name */
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| #define MODULECMD_ARG_OUTPUT      11 /**< DCB suitable for writing results to.
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|                                           This should always be the first argument
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|                                           if the function requires an output DCB. */
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| 
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| /**
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|  * Options for arguments, bits 9 through 32
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|  */
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| #define MODULECMD_ARG_OPTIONAL (1 << 8) /**< The argument is optional */
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| 
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| /**
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|  * Helper macros
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|  */
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| #define MODULECMD_GET_TYPE(t) ((t)->type & 0xff)
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| #define MODULECMD_ARG_IS_REQUIRED(t) (((t)->type & MODULECMD_ARG_OPTIONAL) == 0)
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| #define MODULECMD_ARG_PRESENT(t) (MODULECMD_GET_TYPE(t) != MODULECMD_ARG_NONE)
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| 
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| /** Argument list node */
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| struct arg_node
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| {
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|     modulecmd_arg_type_t  type;
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|     union
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|     {
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|         char       *string;
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|         bool        boolean;
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|         SERVICE    *service;
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|         SERVER     *server;
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|         SESSION    *session;
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|         DCB        *dcb;
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|         MONITOR    *monitor;
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|         FILTER_DEF *filter;
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|     } value;
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| };
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| 
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| /** Argument list */
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| typedef struct
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| {
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|     int              argc;
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|     struct arg_node *argv;
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| } MODULECMD_ARG;
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| 
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| /**
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|  * The function signature for the module commands.
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|  *
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|  * The number of arguments will always be the maximum number of arguments the
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|  * module requested. If an argument had the MODULECMD_ARG_OPTIONAL flag, and
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|  * the argument was not provided, the type of the argument will be
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|  * MODULECMD_ARG_NONE.
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|  *
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|  * @param argv Argument list
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|  * @return True on success, false on error
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|  */
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| typedef bool (*MODULECMDFN)(const MODULECMD_ARG *argv);
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| 
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| /**
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|  * A registered command
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|  */
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| typedef struct modulecmd
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| {
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|     char                 *identifier; /**< Unique identifier */
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|     char                 *domain; /**< Command domain */
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|     MODULECMDFN           func; /**< The registered function */
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|     int                   arg_count_min; /**< Minimum number of arguments */
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|     int                   arg_count_max; /**< Maximum number of arguments */
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|     modulecmd_arg_type_t *arg_types; /**< Argument types */
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|     struct modulecmd     *next; /**< Next command */
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| } MODULECMD;
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| 
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| /**
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|  * @brief Register a new command
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|  *
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|  * This function registers a new command into the domain.
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|  *
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|  * @param domain Command domain
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|  * @param identifier The unique identifier for this command
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|  * @param entry_point The actual entry point function
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|  * @param argc Maximum number of arguments
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|  * @param argv Array of argument types of size @c argc
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|  * @return True if the module was successfully registered, false on error
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|  */
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| bool modulecmd_register_command(const char *domain, const char *identifier,
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|                                 MODULECMDFN entry_point, int argc, modulecmd_arg_type_t *argv);
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| 
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| /**
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|  * @brief Find a registered command
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|  *
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|  * @param domain Command domain
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|  * @param identifier Command identifier
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|  * @return Registered command or NULL if no command was found
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|  */
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| const MODULECMD* modulecmd_find_command(const char *domain, const char *identifier);
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| 
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| /**
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|  * @brief Parse arguments for a command
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|  *
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|  * @param cmd Command for which the parameters are parsed
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|  * @param argc Number of arguments
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|  * @param argv Argument list in string format of size @c argc
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|  * @return Parsed arguments or NULL on error
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|  */
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| MODULECMD_ARG* modulecmd_arg_parse(const MODULECMD *cmd, int argc, const void **argv);
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| 
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| /**
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|  * @brief Free parsed arguments returned by modulecmd_arg_parse
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|  * @param arg Arguments to free
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|  */
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| void modulecmd_arg_free(MODULECMD_ARG *arg);
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| 
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| /**
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|  * @brief Check if an optional argument was defined
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|  *
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|  * This function looks the argument list @c arg at an offset of @c idx and
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|  * checks if the argument list contains a value for an optional argument.
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|  *
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|  * @param arg Argument list
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|  * @param idx Index of the argument, starts at 0
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|  * @return True if the optional argument is present
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|  */
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| bool modulecmd_arg_is_present(const MODULECMD_ARG *arg, int idx);
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| 
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| /**
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|  * @brief Call a registered command
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|  *
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|  * This calls a registered command in a specific domain. There are no guarantees
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|  * on the length of the call or whether it will block. All of this depends on the
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|  * module and what the command does.
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|  *
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|  * @param cmd Command to call
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|  * @param args Parsed command arguments
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|  * @return True on success, false on error
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|  */
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| bool modulecmd_call_command(const MODULECMD *cmd, const MODULECMD_ARG *args);
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| 
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| /**
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|  * @brief Set the current error message
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|  *
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|  * Modules that register commands should use this function to report errors.
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|  * This will overwrite any existing error message.
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|  *
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|  * @param format Format string
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|  * @param ... Format string arguments
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|  */
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| void modulecmd_set_error(const char *format, ...);
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| 
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| /**
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|  * @brief Get the latest error generated by the modulecmd system
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|  *
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|  * @return Human-readable error message
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|  */
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| const char* modulecmd_get_error();
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| 
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| 
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| /**
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|  * @brief Call a function for each command
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|  *
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|  * Calls a function for each matching command in the matched domains. The filters
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|  * for the domain and identifier are PCRE2 expressions that are matched against
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|  * the domain and identifier. These are optional and both @c domain and @c ident
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|  * can be NULL.
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|  *
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|  * @param domain_re Command domain filter, NULL for all domains
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|  *
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|  * @param ident_re Command identifier filter, NULL for all commands
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|  *
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|  * @param fn Function that is called for every command. The first parameter is
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|  *           the current command. The second parameter is the value of @c data.
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|  *           The function should return true to continue iteration or false to
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|  *           stop iteration early. The function must not call any of the functions
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|  *           declared in modulecmd.h.
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|  *
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|  * @param data User defined data passed as the second parameter to @c fn
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|  *
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|  * @return True on success, false on PCRE2 error. Use modulecmd_get_error()
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|  * to retrieve the error.
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|  */
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| bool modulecmd_foreach(const char *domain_re, const char *ident_re,
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|                        bool(*fn)(const MODULECMD *cmd, void *data), void *data);
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| 
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| /**
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|  * @brief Return argument type as string
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|  *
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|  * This returns the string type of @c type. The returned string must be freed
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|  * by the called.
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|  *
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|  * @param type Type to convert
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|  * @return New string or NULL on memory allocation error
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|  */
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| char* modulecmd_argtype_to_str(modulecmd_arg_type_t *type);
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| 
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| MXS_END_DECLS
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