/usr/man/cat.3/CONF_modules_load.3

CONF_modules_load_file(3)    OpenSSL    CONF_modules_load_file(3)

NAME

      CONF_modules_load_file, CONF_modules_load - OpenSSL configuration functions

SYNOPSIS

      #include <openssl/conf.h>

      int CONF_modules_load_file(const char *filename, const char *appname,
                                             unsigned long flags);
      int CONF_modules_load(const CONF *cnf, const char *appname,
                                    unsigned long flags);

DESCRIPTION

     The function CONF_modules_load_file() configures OpenSSL
     using file filename and application name appname. If
     filename is NULL the standard OpenSSL configuration file is
     used. If appname is NULL the standard OpenSSL application
     name openssl_conf is used.  The behaviour can be cutomized
     using flags.

     CONF_modules_load() is idential to CONF_modules_load_file()
     except it reads configuration information from cnf.

NOTES

     The following flags are currently recognized:

     CONF_MFLAGS_IGNORE_ERRORS if set errors returned by
     individual configuration modules are ignored. If not set the
     first module error is considered fatal and no further
     modules are loaded.

     Normally any modules errors will add error information to
     the error queue. If CONF_MFLAGS_SILENT is set no error
     information is added.

     If CONF_MFLAGS_NO_DSO is set configuration module loading
     from DSOs is disabled.

     CONF_MFLAGS_IGNORE_MISSING_FILE if set will make
     CONF_load_modules_file() ignore missing configuration files.
     Normally a missing configuration file return an error.

     CONF_MFLAGS_DEFAULT_SECTION if set and appname is not NULL
     will use the default section pointed to by openssl_conf if
     appname does not exist.

     Applications should call these functions after loading
     builtin modules using OPENSSL_load_builtin_modules(), any
     ENGINEs for example using ENGINE_load_builtin_engines(), any
     algorithms for example OPENSSL_add_all_algorithms() and (if
     the application uses libssl) SSL_library_init().

1.0.2t               Last change: 2019-09-10                    1

CONF_modules_load_file(3)    OpenSSL    CONF_modules_load_file(3)

     By using CONF_modules_load_file() with appropriate flags an
     application can customise application configuration to best
     suit its needs. In some cases the use of a configuration
     file is optional and its absence is not an error: in this
     case CONF_MFLAGS_IGNORE_MISSING_FILE would be set.

     Errors during configuration may also be handled differently
     by different applications. For example in some cases an
     error may simply print out a warning message and the
     application continue. In other cases an application might
     consider a configuration file error as fatal and exit
     immediately.

     Applications can use the CONF_modules_load() function if
     they wish to load a configuration file themselves and have
     finer control over how errors are treated.

EXAMPLES

     Load a configuration file and print out any errors and exit
     (missing file considered fatal):

      if (CONF_modules_load_file(NULL, NULL, 0) <= 0) {
         fprintf(stderr, "FATAL: error loading configuration file\n");
         ERR_print_errors_fp(stderr);
         exit(1);
      }

     Load default configuration file using the section indicated
     by "myapp", tolerate missing files, but exit on other
     errors:

      if (CONF_modules_load_file(NULL, "myapp",
                                 CONF_MFLAGS_IGNORE_MISSING_FILE) <= 0) {
         fprintf(stderr, "FATAL: error loading configuration file\n");
         ERR_print_errors_fp(stderr);
         exit(1);
      }

     Load custom configuration file and section, only print
     warnings on error, missing configuration file ignored:

      if (CONF_modules_load_file("/something/app.cnf", "myapp",
                                 CONF_MFLAGS_IGNORE_MISSING_FILE) <= 0) {
         fprintf(stderr, "WARNING: error loading configuration file\n");
         ERR_print_errors_fp(stderr);
      }

     Load and parse configuration file manually, custom error
     handling:

1.0.2t               Last change: 2019-09-10                    2

CONF_modules_load_file(3)    OpenSSL    CONF_modules_load_file(3)

      FILE *fp;
      CONF *cnf = NULL;
      long eline;
      fp = fopen("/somepath/app.cnf", "r");
      if (fp == NULL) {
         fprintf(stderr, "Error opening configuration file\n");
         /* Other missing configuration file behaviour */
      } else {
         cnf = NCONF_new(NULL);
         if (NCONF_load_fp(cnf, fp, &eline) == 0) {
             fprintf(stderr, "Error on line %ld of configuration file\n", eline);
             ERR_print_errors_fp(stderr);
             /* Other malformed configuration file behaviour */
         } else if (CONF_modules_load(cnf, "appname", 0) <= 0) {
           fprintf(stderr, "Error configuring application\n");
           ERR_print_errors_fp(stderr);
           /* Other configuration error behaviour */
         }
         fclose(fp);
         NCONF_free(cnf);
       }

RETURN VALUES

     These functions return 1 for success and a zero or negative
     value for failure. If module errors are not ignored the
     return code will reflect the return value of the failing
     module (this will always be zero or negative).

SEE ALSO

     conf(5), OPENSSL_config(3), CONF_free(3), err(3)

HISTORY

     CONF_modules_load_file and CONF_modules_load first appeared
     in OpenSSL 0.9.7.

1.0.2t               Last change: 2019-09-10                    3

See also CONF_modules_load_file(3)