openairinterface5g/common/config/DOC/config/devusage/api.md

config module management

configmodule_interface_t *load_configmodule(int argc, char **argv, uint32_t initflags)

• Parses the command line options, looking for the –O argument
• Loads the libparams_<configsource>.so (today libparams_libconfig.so) shared library
• Looks for config_<config source>_init symbol and calls it , passing it an array of string corresponding to the « : » separated strings used in the –O option
• Looks for config_<config source>_get, config_<config source>_getlist and config_<config source>_end symbols which are the three functions a configuration library should implement. Get and getlist are mandatory, end is optional.
• Stores all the necessary information in a configmodule_interface_t structure, which is of no use for caller as long as we only use one configuration source.
• if the bit CONFIG_ENABLECMDLINEONLY is set in initflags then the module allows parameters to be set only via the command line. This is used for the oai UE.

void end_configmodule(void)

• Free memory which has been allocated by the configuration module for storing parameters values, when PARAMFLAG_NOFREE flag is not specified in the parameter definition.
• Possibly calls the config_<config source>_end function This call should be used when all configurations have been read. The program will still be able to use parameter values allocated by the config module WHEN THE PARAMFLAG_NOFREE flag has been specified in the parameter definition. The config module can be reloaded later in the program (not fully tested as not used today)

Retrieving parameter's values

int config_get(paramdef_t *params,int numparams, char *prefix)

• Reads as many parameters as described in params, they must all be in the same configuration file section

• Calls the config_<config source>_get function

• Calls the config_process_cmdline function

• params points to an array of paramdef_t structures which describes the parameters to be read, possibly including a pointer to a checking function.The paramflags bit mask can be used to modify how a specific parameter is processed and the same mask is also used by the configuration module to return information about how the parameter has been processed. Bits definitions are described in the paramdef_t structure description

• numparams is the number of entries in the params array

• prefix is a character string to be appended to the parameters name, it defines the parameters position in the configuration file hierarchy (the section name in libconfig terminology).

• The returned value is the number of parameters which have been assigned a value or -1 if a severe error occured

int config_libconfig_getlist(paramlist_def_t *ParamList, paramdef_t *params, int numparams, char *prefix)

• Reads multiple occurrences of a parameters array
• Calls the config_<config source>_get function for each list occurrence
• params points to an array of paramdef_t structures which describes the parameters in each occurrence of the list
• ParamList points to a structure, where paramarray field points to an array of paramdef_t structure, allocated by the function. It is used to return the values of the parameters.
• The returned value is the number of occurrences in the list or -1 in case of severe error

utility functions and macros

The configuration module also defines APIs to access the paramdef_t and configmodule_interface_t fields. They are listed in the configuration module include file common/config/config_userapi.h

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