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Diffstat (limited to 'src/extensions/extension_age_restriction.c')
-rw-r--r-- | src/extensions/extension_age_restriction.c | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/src/extensions/extension_age_restriction.c b/src/extensions/extension_age_restriction.c new file mode 100644 index 000000000..a9ffb7f1a --- /dev/null +++ b/src/extensions/extension_age_restriction.c @@ -0,0 +1,321 @@ +/* + This file is part of TALER + Copyright (C) 2021-2022 Taler Systems SA + + TALER 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, or (at your option) any later version. + + TALER 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 + TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/> + */ +/** + * @file extension_age_restriction.c + * @brief Utility functions regarding age restriction + * @author Özgür Kesim + */ +#include "platform.h" +#include "taler_util.h" +#include "taler_extensions.h" +#include "stdint.h" + + +/** + * @param groups String representation of the age groups. Must be of the form + * a:b:...:n:m + * with + * 0 < a < b <...< n < m < 32 + * @param[out] mask Bit representation of the age groups. + * @return Error if string was invalid, OK otherwise. + */ +enum GNUNET_GenericReturnValue +TALER_parse_age_group_string ( + const char *groups, + struct TALER_AgeMask *mask) +{ + + const char *pos = groups; + unsigned int prev = 0; + unsigned int val = 0; + char c; + + while (*pos) + { + c = *pos++; + if (':' == c) + { + if (prev >= val) + return GNUNET_SYSERR; + + mask->mask |= 1 << val; + prev = val; + val = 0; + continue; + } + + if ('0'>c || '9'<c) + return GNUNET_SYSERR; + + val = 10 * val + c - '0'; + + if (0>=val || 32<=val) + return GNUNET_SYSERR; + } + + if (0>val || 32<=val || prev>=val) + return GNUNET_SYSERR; + + mask->mask |= (1 << val); + mask->mask |= 1; // mark zeroth group, too + + return GNUNET_OK; +} + + +/** + * Encodes the age mask into a string, like "8:10:12:14:16:18:21" + * + * @param mask Age mask + * @return String representation of the age mask, allocated by GNUNET_malloc. + * Can be used as value in the TALER config. + */ +char * +TALER_age_mask_to_string ( + const struct TALER_AgeMask *m) +{ + uint32_t mask = m->mask; + unsigned int n = 0; + char *buf = GNUNET_malloc (32 * 3); // max characters possible + char *pos = buf; + + if (NULL == buf) + { + return buf; + } + + while (mask != 0) + { + mask >>= 1; + n++; + if (0 == (mask & 1)) + { + continue; + } + + if (n > 9) + { + *(pos++) = '0' + n / 10; + } + *(pos++) = '0' + n % 10; + + if (0 != (mask >> 1)) + { + *(pos++) = ':'; + } + } + return buf; +} + + +/* ================================================== + * + * Age Restriction TALER_Extension imlementation + * + * ================================================== + */ + + +/** + * @brief implements the TALER_Extension.disable interface. + */ +void +age_restriction_disable ( + struct TALER_Extension *this) +{ + if (NULL == this) + return; + + this->config = NULL; + + if (NULL != this->config_json) + { + json_decref (this->config_json); + this->config_json = NULL; + } +} + + +/** + * @brief implements the TALER_Extension.load_taler_config interface. + * @param cfg Handle to the GNUNET configuration + * @param[out] enabled Set to true if age restriction is enabled in the config, false otherwise. + * @param[out] mask Mask for age restriction. Will be 0 if age restriction was not enabled in the config. + * @return Error if extension for age restriction was set, but age groups were + * invalid, OK otherwise. + */ +static enum GNUNET_GenericReturnValue +age_restriction_load_taler_config ( + struct TALER_Extension *this, + const struct GNUNET_CONFIGURATION_Handle *cfg) +{ + char *groups = NULL; + enum GNUNET_GenericReturnValue ret = GNUNET_SYSERR; + struct TALER_AgeMask mask = {0}; + + if ((GNUNET_YES != + GNUNET_CONFIGURATION_have_value (cfg, + TALER_EXTENSION_SECTION_AGE_RESTRICTION, + "ENABLED")) + || + (GNUNET_YES != + GNUNET_CONFIGURATION_get_value_yesno (cfg, + TALER_EXTENSION_SECTION_AGE_RESTRICTION, + "ENABLED"))) + { + /* Age restriction is not enabled */ + this->config = NULL; + this->config_json = NULL; + return GNUNET_OK; + } + + /* Age restriction is enabled, extract age groups */ + if ((GNUNET_YES == + GNUNET_CONFIGURATION_have_value (cfg, + TALER_EXTENSION_SECTION_AGE_RESTRICTION, + "AGE_GROUPS")) + && + (GNUNET_YES != + GNUNET_CONFIGURATION_get_value_string (cfg, + TALER_EXTENSION_SECTION_AGE_RESTRICTION, + "AGE_GROUPS", + &groups))) + return GNUNET_SYSERR; + + + mask.mask = TALER_EXTENSION_AGE_RESTRICTION_DEFAULT_AGE_MASK; + + ret = GNUNET_OK; + + if (groups != NULL) + { + ret = TALER_parse_age_group_string (groups, &mask); + if (GNUNET_OK != ret) + mask.mask = TALER_EXTENSION_AGE_RESTRICTION_DEFAULT_AGE_MASK; + } + + if (GNUNET_OK == ret) + this->config = (void *) (size_t) mask.mask; + + GNUNET_free (groups); + return ret; +} + + +/** + * @brief implements the TALER_Extension.load_json_config interface. + * @param this if NULL, only tests the configuration + * @param config the configuration as json + */ +static enum GNUNET_GenericReturnValue +age_restriction_load_json_config ( + struct TALER_Extension *this, + json_t *config) +{ + struct TALER_AgeMask mask = {0}; + enum GNUNET_GenericReturnValue ret; + + ret = TALER_JSON_parse_agemask (config, &mask); + if (GNUNET_OK != ret) + return ret; + + /* only testing the parser */ + if (this == NULL) + return GNUNET_OK; + + if (TALER_Extension_AgeRestriction != this->type) + return GNUNET_SYSERR; + + if (NULL != this->config) + GNUNET_free (this->config); + + this->config = GNUNET_malloc (sizeof(struct TALER_AgeMask)); + GNUNET_memcpy (this->config, &mask, sizeof(struct TALER_AgeMask)); + + if (NULL != this->config_json) + json_decref (this->config_json); + + this->config_json = config; + + return GNUNET_OK; +} + + +/** + * @brief implements the TALER_Extension.load_json_config interface. + * @param this if NULL, only tests the configuration + * @param config the configuration as json + */ +json_t * +age_restriction_config_to_json ( + const struct TALER_Extension *this) +{ + struct TALER_AgeMask mask; + char *mask_str; + json_t *conf; + + GNUNET_assert (NULL != this); + GNUNET_assert (NULL != this->config); + + if (NULL != this->config_json) + { + return json_copy (this->config_json); + } + + mask.mask = (uint32_t) (size_t) this->config; + mask_str = TALER_age_mask_to_string (&mask); + conf = GNUNET_JSON_PACK ( + GNUNET_JSON_pack_string ("age_groups", mask_str) + ); + + return GNUNET_JSON_PACK ( + GNUNET_JSON_pack_bool ("critical", this->critical), + GNUNET_JSON_pack_string ("version", this->version), + GNUNET_JSON_pack_object_steal ("config", conf) + ); +} + + +/** + * @brief implements the TALER_Extension.test_json_config interface. + */ +static enum GNUNET_GenericReturnValue +age_restriction_test_json_config ( + const json_t *config) +{ + struct TALER_AgeMask mask = {0}; + + return TALER_JSON_parse_agemask (config, &mask); +} + + +/* The extension for age restriction */ +struct TALER_Extension _extension_age_restriction = { + .next = NULL, + .type = TALER_Extension_AgeRestriction, + .name = "age_restriction", + .critical = false, + .version = "1", + .config = NULL, // disabled per default + .config_json = NULL, + .disable = &age_restriction_disable, + .test_json_config = &age_restriction_test_json_config, + .load_json_config = &age_restriction_load_json_config, + .config_to_json = &age_restriction_config_to_json, + .load_taler_config = &age_restriction_load_taler_config, +}; + +/* end of extension_age_restriction.c */ |