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| -rw-r--r-- | ctdb/common/conf.h | 473 |
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diff --git a/ctdb/common/conf.h b/ctdb/common/conf.h new file mode 100644 index 0000000..6b152c1 --- /dev/null +++ b/ctdb/common/conf.h @@ -0,0 +1,473 @@ +/* + Configuration file handling on top of tini + + Copyright (C) Amitay Isaacs 2017 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef __CTDB_CONF_H__ +#define __CTDB_CONF_H__ + +#include <stdio.h> +#include <stdbool.h> +#include <talloc.h> + +/** + * @file conf.h + * + * @brief Configuration file handling with sections and key-value pairs + * + * CTDB settings can be written in a configuration file ctdb.conf (similar to + * samba's smb.conf). Various daemons and tools will consult the configuration + * file for runtime settings. + * + * The configuration will be organized in sections depending on various + * components. Each section will have various configuration options in the form + * of key-value pairs. + * + * [section1] + * key1 = value1 + * ... + * + * [section2] + * key2 = value2 + * ... + * + * ... + * + */ + +/** + * @brief Abstract data structure holding the configuration options + */ +struct conf_context; + +/** + * @brief configuration option update mode + * + * When a value of configuration option is changed, update mode is set + * appropriately. + * + * CONF_MODE_API - value modified using set functions + * CONF_MODE_LOAD - value modified via conf_load + * CONF_MODE_RELOAD - value modified via conf_reload + */ +enum conf_update_mode { + CONF_MODE_API, + CONF_MODE_LOAD, + CONF_MODE_RELOAD, +}; + +/** + * @brief configuration option type + */ +enum conf_type { + CONF_STRING, + CONF_INTEGER, + CONF_BOOLEAN, +}; + +/** + * @brief Configuration section validation function + * + * Check if all the configuration options are consistent with each-other + */ +typedef bool (*conf_validate_section_fn)(struct conf_context *conf, + const char *section, + enum conf_update_mode mode); + +/** + * @brief Configuration option validation function for string + * + * Check if a configuration option value is valid + */ +typedef bool (*conf_validate_string_option_fn)(const char *key, + const char *old_value, + const char *new_value, + enum conf_update_mode mode); + +/** + * @brief Configuration option validation function for integer + * + * Check if a configuration option value is valid + */ +typedef bool (*conf_validate_integer_option_fn)(const char *key, + int old_value, + int new_value, + enum conf_update_mode mode); + +/** + * @brief Configuration option validation function for boolean + * + * Check if a configuration option value is valid + */ +typedef bool (*conf_validate_boolean_option_fn)(const char *key, + bool old_value, + bool new_value, + enum conf_update_mode mode); + +/** + * @brief Initialize configuration option database + * + * This return a new configuration options context. Freeing this context will + * free up all the memory associated with the configuration options. + * + * @param[in] mem_ctx Talloc memory context + * @param[in] result The new configuration options context + * @return 0 on success, errno on failure + */ +int conf_init(TALLOC_CTX *mem_ctx, struct conf_context **result); + +/** + * @brief Define a section for organizing configuration options + * + * This functions creates a section to organize configuration option. The + * section names are case-insensitive and are always stored in lower case. + * + * @param[in] conf The configuration options context + * @param[in] section The name of the section + * @param[in] validate The validation function for configuration options + */ +void conf_define_section(struct conf_context *conf, + const char *section, + conf_validate_section_fn validate); + +/** + * @brief Define a configuration option which has a string value + * + * This functions adds a new configuration option organized under a given + * section. Configuration options are case-insensitive and are always stored + * in lower case. + * + * @param[in] conf The configuration options context + * @param[in] section The name of the section + * @param[in] key The name of the configuration option + * @param[in] default_value The default value for the configuration option + * @param[in] validate The validation function for the configuration option + */ +void conf_define_string(struct conf_context *conf, + const char *section, + const char *key, + const char *default_value, + conf_validate_string_option_fn validate); + +/** + * @brief Define a configuration option which has an integer value + * + * This functions adds a new configuration option organized under a given + * section. Configuration options are case-insensitive and are always stored + * in lower case. + * + * @param[in] conf The configuration options context + * @param[in] section The name of the section + * @param[in] key The name of the configuration option + * @param[in] default_value The default value for the configuration option + * @param[in] validate The validation function for the configuration option + */ +void conf_define_integer(struct conf_context *conf, + const char *section, + const char *key, + const int default_value, + conf_validate_integer_option_fn validate); + +/** + * @brief Define a configuration option which has an boolean value + * + * This functions adds a new configuration option organized under a given + * section. Configuration options are case-insensitive and are always stored + * in lower case. + * + * @param[in] conf The configuration options context + * @param[in] section The name of the section + * @param[in] key The name of the configuration option + * @param[in] default_value The default value for the configuration option + * @param[in] validate The validation function for the configuration option + */ +void conf_define_boolean(struct conf_context *conf, + const char *section, + const char *key, + const bool default_value, + conf_validate_boolean_option_fn validate); + +/** + * @brief Assign user-accessible pointer for string option + * + * This pointer can be used for accessing the value of configuration option + * directly without requiring a function call. + * + * @param[in] conf The configuration options context + * @param[in] section The name of the section + * @param[in] key The name of the configuration option + * @param[in] ptr User-accessible pointer to the value + */ +void conf_assign_string_pointer(struct conf_context *conf, + const char *section, + const char *key, + const char **ptr); + +/** + * @brief Assign user-accessible pointer for integer option + * + * This pointer can be used for accessing the value of configuration option + * directly without requiring a function call. + * + * @param[in] conf The configuration options context + * @param[in] section The name of the section + * @param[in] key The name of the configuration option + * @param[in] ptr User-accessible pointer to the value + */ +void conf_assign_integer_pointer(struct conf_context *conf, + const char *section, + const char *key, + int *ptr); + +/** + * @brief Assign user-accessible pointer for boolean option + * + * This pointer can be used for accessing the value of configuration option + * directly without requiring a function call. + * + * @param[in] conf The configuration options context + * @param[in] section The name of the section + * @param[in] key The name of the configuration option + * @param[in] ptr User-accessible pointer to the value + * @return true on success, false on failure + */ +void conf_assign_boolean_pointer(struct conf_context *conf, + const char *section, + const char *key, + bool *ptr); + +/** + * @brief Query a configuration option + * + * This function checks if a configuration option is defined or not. + * + * @param[in] conf The configuration options context + * @param[in] section The name of the section + * @param[in] key The name of the configuration option + * @param[out] type The type of the configuration option + * @return true on success, false if section/option is not defined + */ +bool conf_query(struct conf_context *conf, + const char *section, + const char *key, + enum conf_type *type); + +/** + * @brief Check if the defined configuration options are valid + * + * This function must be called after creating configuration options + * to confirm that all the option definitions are valid. + * + * @param[in] conf The configuration options context + * @return true on success, false on failure + */ +bool conf_valid(struct conf_context *conf); + +/** + * @brief Set the default values for all configuration options + * + * This function resets all the configuration options to their default values. + * + * @param[in] conf The connfiguration options context + */ +void conf_set_defaults(struct conf_context *conf); + +/** + * @brief Load the values for configuration option values from a file + * + * This function will update the values of the configuration options from those + * specified in a file. This function will fail in case it encounters an + * undefined option. Any sections which are not defined, will be ignored. + * + * This function will call validation function (if specified) before updating + * the value of a configuration option. After updating all the values for a + * section, the validation for section (if specified) will be called. If any + * of the validation functions return error, then all the configuration + * options will be reset to their previous values. + * + * @param[in] conf The configuration options context + * @param[in] filename The configuration file + * @param[in] skip_unknown Whether unknown config options should be ignored + * @return 0 on success, errno on failure + */ +int conf_load(struct conf_context *conf, + const char *filename, + bool ignore_unknown); + +/** + * @brief Reload the values for configuration options + * + * This function will re-load the values of the configuration options. This + * function can be called only after succesful call to conf_load(). + * + * @see conf_load + * + * @param[in] conf The configuration options context + * @return 0 on success, errno on failure. + */ +int conf_reload(struct conf_context *conf); + +/** + * @brief Set the string value of a configuration option + * + * This function can be used to update the value of a configuration option. + * This will call the validation function for that option (if defined) and + * the section validation function (if defined). + * + * If a user-defined storage pointer is provided, then the value of a + * configuration option should not be changed via that pointer. + * + * @param[in] conf The configuration options context + * @param[in] section The name of a section + * @param[in] key The name of a configuration option + * @param[in] str_val The string value + * @return 0 on success, errno in case of failure + */ +int conf_set_string(struct conf_context *conf, + const char *section, + const char *key, + const char *str_val); + +/** + * @brief Set the integer value of a configuration option + * + * This function can be used to update the value of a configuration option. + * This will call the validation function for that option (if defined) and + * the section validation function (if defined). + * + * If a user-defined storage pointer is provided, then the value of a + * configuration option should not be changed via that pointer. + * + * @param[in] conf The configuration options context + * @param[in] section The name of a section + * @param[in] key The name of a configuration option + * @param[in] int_val The integer value + * @return 0 on success, errno in case of failure + */ +int conf_set_integer(struct conf_context *conf, + const char *section, + const char *key, + int int_val); + +/** + * @brief Set the boolean value of a configuration option + * + * This function can be used to update the value of a configuration option. + * This will call the validation function for that option (if defined) and + * the section validation function (if defined). + * + * If a user-defined storage pointer is provided, then the value of a + * configuration option should not be changed via that pointer. + * + * @param[in] conf The configuration options context + * @param[in] section The name of a section + * @param[in] key The name of a configuration option + * @param[in] bool_val The boolean value + * @return 0 on success, errno in case of failure + */ +int conf_set_boolean(struct conf_context *conf, + const char *section, + const char *key, + bool bool_val); + +/** + * @brief Get the string value of a configuration option + * + * This function can be used to fetch the current value of a configuration + * option. + * + * If a user-defined storage pointer is provided, then the value of a + * configuration option can be accessed directly via that pointer. + * + * @param[in] conf The configuration options context + * @param[in] section The name of a section + * @param[in] key The name of a configuration option + * @param[out] str_val The string value of the configuration option + * @param[out] is_default True if the value is default value + * @return 0 on success, errno in case of failure + */ +int conf_get_string(struct conf_context *conf, + const char *section, + const char *key, + const char **str_val, + bool *is_default); + +/** + * @brief Get the integer value of a configuration option + * + * This function can be used to fetch the current value of a configuration + * option. + * + * If a user-defined storage pointer is provided, then the value of a + * configuration option can be accessed directly via that pointer. + * + * @param[in] conf The configuration options context + * @param[in] section The name of a section + * @param[in] key The name of a configuration option + * @param[out] int_val The integer value of the configuration option + * @param[out] is_default True if the value is default value + * @return 0 on success, errno in case of failure + */ +int conf_get_integer(struct conf_context *conf, + const char *section, + const char *key, + int *int_val, + bool *is_default); + +/** + * @brief Get the boolean value of a configuration option + * + * This function can be used to fetch the current value of a configuration + * option. + * + * If a user-defined storage pointer is provided, then the value of a + * configuration option can be accessed directly via that pointer. + * + * @param[in] conf The configuration options context + * @param[in] section The name of a section + * @param[in] key The name of a configuration option + * @param[out] bool_val The boolean value of the configuration option + * @param[out] is_default True if the value is default value + * @return 0 on success, errno in case of failure + */ +int conf_get_boolean(struct conf_context *conf, + const char *section, + const char *key, + bool *bool_val, + bool *is_default); + +/** + * @brief Dump the configuration in a file + * + * All the configuration options are dumped with their current values. + * If an option has a default value, then it is commented. + * + * Here is a sample output: + * + * [section1] + * key1 = value1 + * key2 = value2 + * # key3 = default_value3 + * [section2] + * key4 = value4 + * + * @param[in] conf The configuration options context + * @param[in] fp File pointer + */ +void conf_dump(struct conf_context *conf, FILE *fp); + +#endif /* __CTDB_CONF_H__ */ |