/* Copyright (c) 2009 Open Information Security Foundation */ /** * This file provides a basic configuration system for the IDPS * engine. * * NOTE: Setting values should only be done from one thread during * engine initialization. Multiple threads should be able access read * configuration data. Allowing run time changes to the configuration * will require some locks. * * \author Endace Technology Limited * * \todo Consider using HashListTable to allow easy dumping of all data. */ #include #include #include #include "eidps-common.h" #include "conf.h" #include "util-hash.h" #include "util-unittest.h" #undef CONF_DEBUG #ifdef CONF_DEBUG #define DPRINTF(x) do { printf x ; } while (0) #else #define DPRINTF(x) #endif /* CONF_DEBUG */ #define CONF_HASH_TBL_SIZE 1024 static HashTable *conf_hash = NULL; /** * Structure of a configuration parameter. */ typedef struct ConfNode_ { char *name; char *val; int allow_override; } ConfNode; /** * \brief Function to generate the hash of a configuration value. * * This is a callback function provided to HashTable for creating the * hash key. Its a simple wrapper around the generic hash function * the passes on the configuration parameter name. * * \retval The hash ID of the configuration parameters name. */ static uint32_t ConfHashFunc(HashTable *ht, void *data, uint16_t len) { ConfNode *cn = (ConfNode *)data; uint32_t hash; hash = HashTableGenericHash(ht, cn->name, strlen(cn->name)); DPRINTF(("%s: %s -> %" PRIu32 "\n", __func__, cn->name, hash)); return hash; } /** * \brief Function to compare 2 hash nodes. * * This is a callback function provided to the HashTable for comparing * 2 nodes. * * \retval 1 if equivalant otherwise 0. */ static char ConfHashComp(void *a, uint16_t a_len, void *b, uint16_t b_len) { ConfNode *ca = (ConfNode *)a; ConfNode *cb = (ConfNode *)b; if (strcmp(ca->name, cb->name) == 0) return 1; else return 0; } /** * \brief Callback function to free a hash node. */ static void ConfHashFree(void *data) { ConfNode *cn = (ConfNode *)data; DPRINTF(("%s: Freeing configuration parameter '%s'\n", __func__, cn->name)); free(cn->name); free(cn->val); free(cn); } /** * \brief Initialize the configuration system. */ void ConfInit(void) { /* Prevent double initialization. */ if (conf_hash != NULL) { DPRINTF(("%s: Already initialized.\n", __func__)); return; } conf_hash = HashTableInit(CONF_HASH_TBL_SIZE, ConfHashFunc, ConfHashComp, ConfHashFree); if (conf_hash == NULL) { fprintf(stderr, "ERROR: Failed to allocate memory for configuration, aborting.\n"); exit(1); } DPRINTF(("%s: Configuration module initialized.\n", __func__)); } /** * \brief Set a configuration value. * * \param name The name of the configuration parameter to set. * \param val The value of the configuration parameter. * \param allow_override Can a subsequent set override this value. * * \retval 1 if the value was set otherwise 0. */ int ConfSet(char *name, char *val, int allow_override) { ConfNode lookup_key, *conf_node; lookup_key.name = name; conf_node = HashTableLookup(conf_hash, &lookup_key, sizeof(lookup_key)); if (conf_node != NULL) { if (!allow_override) { return 0; } HashTableRemove(conf_hash, conf_node, sizeof(*conf_node)); } conf_node = calloc(1, sizeof(*conf_node)); if (conf_node == NULL) { return 0; } conf_node->name = strdup(name); conf_node->val = strdup(val); conf_node->allow_override = allow_override; if (HashTableAdd(conf_hash, conf_node, sizeof(*conf_node)) != 0) { fprintf(stderr, "ERROR: Failed to set configuration parameter %s\n", name); exit(1); } DPRINTF(("%s: Configuration parameter '%s' set.\n", __func__, name)); return 1; } /** * \brief Retrieve a configuration value. * * \param name Name of configuration parameter to get. * \param vptr Pointer that will be set to the configuration value parameter. * Note that this is just a reference to the actual value, not a copy. * * \retval 1 will be returned if the name is found, otherwise 0 will * be returned. */ int ConfGet(char *name, char **vptr) { ConfNode lookup_key; ConfNode *conf_node; lookup_key.name = name; conf_node = HashTableLookup(conf_hash, &lookup_key, sizeof(lookup_key)); if (conf_node == NULL) { DPRINTF(("%s: Failed to lookup configuration parameter '%s'\n", __func__, name)); return 0; } else { *vptr = conf_node->val; return 1; } } /** * \brief Remove a configuration parameter from the configuration db. * * \param name The name of the configuration parameter to remove. * * \retval Returns 1 if the parameter was removed, otherwise 0 is returned * most likely indicating the parameter was not set. */ int ConfRemove(char *name) { ConfNode cn; cn.name = name; if (HashTableRemove(conf_hash, &cn, sizeof(cn)) == 0) return 1; else return 0; } #ifdef UNITTESTS /** * Lookup a non-existant value. */ static int ConfTestGetNonExistant(void) { char name[] = "non-existant-value"; char *value; return !ConfGet(name, &value); } /** * Set then lookup a value. */ static int ConfTestSetAndGet(void) { char name[] = "some-name"; char value[] = "some-value"; char *value0; if (ConfSet(name, value, 1) != 1) return 0; if (ConfGet(name, &value0) != 1) return 0; if (strcmp(value, value0) != 0) return 0; /* Cleanup. */ ConfRemove(name); return 1; } /** * Test that overriding a value is allowed provided allow_override is * true and that the config parameter gets the new value. */ static int ConfTestOverrideValue1(void) { char name[] = "some-name"; char value0[] = "some-value"; char value1[] = "new-value"; char *val; int rc; if (ConfSet(name, value0, 1) != 1) return 0; if (ConfSet(name, value1, 1) != 1) return 0; if (ConfGet(name, &val) != 1) return 0; rc = !strcmp(val, value1); /* Cleanup. */ ConfRemove(name); return rc; } /** * Test that overriding a value is not allowed provided that * allow_override is false and make sure the value was not overrided. */ static int ConfTestOverrideValue2(void) { char name[] = "some-name"; char value0[] = "some-value"; char value1[] = "new-value"; char *val; int rc; if (ConfSet(name, value0, 0) != 1) return 0; if (ConfSet(name, value1, 0) != 0) return 0; if (ConfGet(name, &val) != 1) return 0; rc = !strcmp(val, value0); /* Cleanup. */ ConfRemove(name); return rc; } void ConfRegisterTests(void) { UtRegisterTest("ConfTestGetNonExistant", ConfTestGetNonExistant, 1); UtRegisterTest("ConfTestSetAndGet", ConfTestSetAndGet, 1); UtRegisterTest("ConfTestOverrideValue1", ConfTestOverrideValue1, 1); UtRegisterTest("ConfTestOverrideValue2", ConfTestOverrideValue2, 1); } #endif /* UNITTESTS */