/*
* get a value from the shared memory cache
*/
static apr_byte_t oidc_cache_shm_get(request_rec *r, const char *section,
const char *key, const char **value) {
oidc_debug(r, "enter, section=\"%s\", key=\"%s\"", section, key);
oidc_cfg *cfg = ap_get_module_config(r->server->module_config,
&auth_openidc_module);
oidc_cache_cfg_shm_t *context = (oidc_cache_cfg_shm_t *) cfg->cache_cfg;
int i;
const char *section_key = oidc_cache_shm_get_key(r->pool, section, key);
*value = NULL;
/* grab the global lock */
if (oidc_cache_mutex_lock(r, context->mutex) == FALSE)
return FALSE;
/* get the pointer to the start of the shared memory block */
oidc_cache_shm_entry_t *t = apr_shm_baseaddr_get(context->shm);
/* loop over the block, looking for the key */
for (i = 0; i < cfg->cache_shm_size_max; i++, OIDC_CACHE_SHM_ADD_OFFSET(t, cfg->cache_shm_entry_size_max)) {
const char *tablekey = t->section_key;
if ( (tablekey != NULL) && (apr_strnatcmp(tablekey, section_key) == 0) ) {
/* found a match, check if it has expired */
if (t->expires > apr_time_now()) {
/* update access timestamp */
t->access = apr_time_now();
*value = t->value;
} else {
/* clear the expired entry */
t->section_key[0] = '\0';
t->access = 0;
}
/* we safely can break now since we would not have found an expired match twice */
break;
}
}
/* release the global lock */
oidc_cache_mutex_unlock(r, context->mutex);
return (*value == NULL) ? FALSE : TRUE;
}
/*
* store a name/value pair in Redis
*/
static apr_byte_t oidc_cache_redis_set(request_rec *r, const char *section,
const char *key, const char *value, apr_time_t expiry) {
oidc_debug(r, "enter, section=\"%s\", key=\"%s\"", section, key);
oidc_cfg *cfg = ap_get_module_config(r->server->module_config,
&auth_openidc_module);
oidc_cache_cfg_redis_t *context = (oidc_cache_cfg_redis_t *) cfg->cache_cfg;
redisReply *reply = NULL;
/* grab the global lock */
if (oidc_cache_mutex_lock(r, context->mutex) == FALSE)
return FALSE;
/* see if we should be clearing this entry */
if (value == NULL) {
/* delete it */
reply = oidc_cache_redis_command(r, context, "DEL %s",
oidc_cache_redis_get_key(r->pool, section, key));
if (reply == NULL) {
oidc_cache_mutex_unlock(r, context->mutex);
return FALSE;
}
freeReplyObject(reply);
} else {
/* calculate the timeout from now */
apr_uint32_t timeout = apr_time_sec(expiry - apr_time_now());
/* store it */
reply = oidc_cache_redis_command(r, context, "SETEX %s %d %s",
oidc_cache_redis_get_key(r->pool, section, key), timeout,
value);
if (reply == NULL) {
oidc_cache_mutex_unlock(r, context->mutex);
return FALSE;
}
freeReplyObject(reply);
}
/* release the global lock */
oidc_cache_mutex_unlock(r, context->mutex);
return TRUE;
}
/*
* get a name/value pair from Redis
*/
static apr_byte_t oidc_cache_redis_get(request_rec *r, const char *section,
const char *key, const char **value) {
oidc_debug(r, "enter, section=\"%s\", key=\"%s\"", section, key);
oidc_cfg *cfg = ap_get_module_config(r->server->module_config,
&auth_openidc_module);
oidc_cache_cfg_redis_t *context = (oidc_cache_cfg_redis_t *) cfg->cache_cfg;
redisReply *reply = NULL;
/* grab the global lock */
if (oidc_cache_mutex_lock(r, context->mutex) == FALSE)
return FALSE;
/* get */
reply = oidc_cache_redis_command(r, context, "GET %s",
oidc_cache_redis_get_key(r->pool, section, key));
if (reply == NULL) {
oidc_cache_mutex_unlock(r, context->mutex);
return FALSE;
}
/* check that we got a string back */
if (reply->type != REDIS_REPLY_STRING) {
freeReplyObject(reply);
/* this is a normal cache miss, so we'll return OK */
oidc_cache_mutex_unlock(r, context->mutex);
return TRUE;
}
/* do a sanity check on the returned value */
if (reply->len != strlen(reply->str)) {
oidc_error(r, "redisCommand reply->len != strlen(reply->str): '%s'",
reply->str);
freeReplyObject(reply);
oidc_cache_mutex_unlock(r, context->mutex);
return FALSE;
}
/* copy it in to the request memory pool */
*value = apr_pstrdup(r->pool, reply->str);
freeReplyObject(reply);
/* release the global lock */
oidc_cache_mutex_unlock(r, context->mutex);
return TRUE;
}
/*
* store a value in the shared memory cache
*/
static apr_byte_t oidc_cache_shm_set(request_rec *r, const char *section,
const char *key, const char *value, apr_time_t expiry) {
oidc_debug(r, "enter, section=\"%s\", key=\"%s\", value size=%llu", section,
key, value ? (unsigned long long )strlen(value) : 0);
oidc_cfg *cfg = ap_get_module_config(r->server->module_config,
&auth_openidc_module);
oidc_cache_cfg_shm_t *context = (oidc_cache_cfg_shm_t *) cfg->cache_cfg;
oidc_cache_shm_entry_t *match, *free, *lru;
oidc_cache_shm_entry_t *t;
apr_time_t current_time;
int i;
apr_time_t age;
const char *section_key = oidc_cache_shm_get_key(r->pool, section, key);
/* check that the passed in key is valid */
if (strlen(section_key) > OIDC_CACHE_SHM_KEY_MAX) {
oidc_error(r, "could not store value since key size is too large (%s)",
section_key);
return FALSE;
}
/* check that the passed in value is valid */
if ((value != NULL) && (strlen(value) > (cfg->cache_shm_entry_size_max - sizeof(oidc_cache_shm_entry_t)))) {
oidc_error(r, "could not store value since value size is too large (%llu > %lu); consider increasing OIDCCacheShmEntrySizeMax",
(unsigned long long)strlen(value), (unsigned long)(cfg->cache_shm_entry_size_max - sizeof(oidc_cache_shm_entry_t)));
return FALSE;
}
/* grab the global lock */
if (oidc_cache_mutex_lock(r, context->mutex) == FALSE)
return FALSE;
/* get a pointer to the shared memory block */
t = apr_shm_baseaddr_get(context->shm);
/* get the current time */
current_time = apr_time_now();
/* loop over the block, looking for the key */
match = NULL;
free = NULL;
lru = t;
for (i = 0; i < cfg->cache_shm_size_max; i++, OIDC_CACHE_SHM_ADD_OFFSET(t, cfg->cache_shm_entry_size_max)) {
/* see if this slot is free */
if (t->section_key[0] == '\0') {
if (free == NULL)
free = t;
continue;
}
/* see if a value already exists for this key */
if (apr_strnatcmp(t->section_key, section_key) == 0) {
match = t;
break;
}
/* see if this slot has expired */
if (t->expires <= current_time) {
if (free == NULL)
free = t;
continue;
}
/* see if this slot was less recently used than the current pointer */
if (t->access < lru->access) {
lru = t;
}
}
/* if we have no free slots, issue a warning about the LRU entry */
if (match == NULL && free == NULL) {
age = (current_time - lru->access) / 1000000;
if (age < 3600) {
oidc_warn(r,
"dropping LRU entry with age = %" APR_TIME_T_FMT "s, which is less than one hour; consider increasing the shared memory caching space (which is %d now) with the (global) OIDCCacheShmMax setting.",
age, cfg->cache_shm_size_max);
}
}
/* pick the best slot: choose one with a matching key over a free slot, over a least-recently-used one */
t = match ? match : (free ? free : lru);
/* see if we need to clear or set the value */
if (value != NULL) {
/* fill out the entry with the provided data */
strcpy(t->section_key, section_key);
strcpy(t->value, value);
t->expires = expiry;
t->access = current_time;
} else {
t->section_key[0] = '\0';
t->access = 0;
}
/* release the global lock */
oidc_cache_mutex_unlock(r, context->mutex);
return TRUE;
}
