diff options
Diffstat (limited to 'src/cyn.c')
| -rw-r--r-- | src/cyn.c | 235 |
1 files changed, 140 insertions, 95 deletions
@@ -14,6 +14,11 @@ * See the License for the specific language governing permissions and * limitations under the License. */ +/******************************************************************************/ +/******************************************************************************/ +/* IMPLEMENTATION OF LOCAL CYNARA API */ +/******************************************************************************/ +/******************************************************************************/ #include <assert.h> #include <stdlib.h> @@ -31,6 +36,9 @@ #if !CYN_SEARCH_DEEP_MAX # define CYN_SEARCH_DEEP_MAX 10 #endif +#if !defined(AGENT_SEPARATOR_CHARACTER) +# define AGENT_SEPARATOR_CHARACTER ':' +#endif /** * items of the list of observers or awaiters @@ -39,14 +47,19 @@ struct callback { /** link to the next item of the list */ struct callback *next; + + /** recording of callback function */ union { /** any callback value */ void *any_cb; + /** awaiter callback */ on_enter_cb_t *on_enter_cb; + /** observer callback */ on_change_cb_t *on_change_cb; }; + /** closure of the callback */ void *closure; }; @@ -65,7 +78,7 @@ struct agent /** closure of the callback */ void *closure; - /** length of the name */ + /** length of the name (without terminating zero) */ uint8_t len; /** name of the agent */ @@ -73,7 +86,7 @@ struct agent }; /** - * structure handling an asynchronous check + * structure handling an asynchronous requests */ struct cyn_query { @@ -86,15 +99,12 @@ struct cyn_query /** key of the check */ data_key_t key; - /** value of the check */ - data_value_t value; - /** down counter for recursivity limitation */ int decount; }; -/** locking critical section */ -static const void *lock; +/** for locking critical section with magic */ +static const void *magic_locker; /** head of the list of critical section awaiters */ static struct callback *awaiters; @@ -102,17 +112,24 @@ static struct callback *awaiters; /** head of the list of change observers */ static struct callback *observers; -/** head of the list of agents */ +/** head of the list of recorded agents */ static struct agent *agents; -/** last changeid */ -static uint32_t last_changeid; +/** holding of changeid */ +static struct { + /** current changeid */ + uint32_t current; -/** changeid of the current 'changeid_string' */ -static uint32_t last_changeid_string; + /** changeid set in string */ + uint32_t instring; -/** string buffer for changeid */ -static char changeid_string[12]; + /** string value for a changeid */ + char string[12]; +} changeid = { + .current = 1, + .instring = 0, + .string = { 0 } +}; /** * Delete from the list represented by 'head' the entry for @@ -179,7 +196,7 @@ changed( ) { struct callback *c; - ++last_changeid; + changeid.current = changeid.current + 1 ?: 1; for (c = observers; c ; c = c->next) c->on_change_cb(c->closure); } @@ -191,9 +208,9 @@ cyn_enter( ) { if (!magic) return -EINVAL; - if (lock) + if (magic_locker) return -EBUSY; - lock = magic; + magic_locker = magic; return 0; } @@ -205,10 +222,10 @@ cyn_enter_async( ) { if (!magic) return -EINVAL; - if (lock) + if (magic_locker) return addcb(enter_cb, magic, &awaiters); - lock = magic; + magic_locker = magic; enter_cb(magic); return 0; } @@ -251,12 +268,12 @@ cyn_leave( if (!magic) return -EINVAL; - if (!lock) + if (!magic_locker) return -EALREADY; - if (lock != magic) + if (magic_locker != magic) return -EPERM; - lock = &lock; + magic_locker = &magic_locker; if (!commit) rc = 0; else { @@ -273,7 +290,7 @@ cyn_leave( /* wake up awaiting client */ e = awaiters; if (!e) - lock = 0; + magic_locker = 0; else { /* the one to awake is at the end of the list */ p = &awaiters; @@ -282,7 +299,7 @@ cyn_leave( e = *p; } *p = NULL; - lock = e->closure; + magic_locker = e->closure; e->on_enter_cb(e->closure); free(e); } @@ -296,7 +313,7 @@ cyn_set( const data_key_t *key, const data_value_t *value ) { - if (!lock) + if (!magic_locker) return -EPERM; return queue_set(key, value); } @@ -306,7 +323,7 @@ int cyn_drop( const data_key_t *key ) { - if (!lock) + if (!magic_locker) return -EPERM; return queue_drop(key); } @@ -314,15 +331,16 @@ cyn_drop( /* see cyn.h */ void cyn_list( - void *closure, list_cb_t *callback, + void *closure, const data_key_t *key ) { - db_for_all(closure, callback, key); + db_for_all(callback, closure, key); } /** * initialize value to its default + * * @param value to initialize * @return the initialized value */ @@ -338,8 +356,9 @@ default_value( /** * Search the agent of name and return its item in the list + * * @param name of the agent to find (optionally zero terminated) - * @param len length of the name + * @param len length of the name (without terminating zero) * @param ppprev for catching the pointer referencing the return item * @return 0 if not found or the pointer to the item of the found agent */ @@ -347,56 +366,51 @@ static struct agent * search_agent( const char *name, - uint8_t len, + size_t length, struct agent ***ppprev ) { struct agent *it, **pprev; pprev = &agents; while((it = *pprev) - && (len != it->len || memcmp(it->name, name, (size_t)len))) + && ((uint8_t)length != it->len || memcmp(it->name, name, length))) pprev = &it->next; *ppprev = pprev; return it; } /** - * Return the agent required by the value or 0 if no agent is required + * Return the agent required by the value or NULL if no agent is required * or if the agent is not found. + * * @param value string where agent is the prefix followed by one colon - * @return the item of the required agent or 0 when no agent is required + * @return the item of the required agent or NULL when no agent is required */ static -struct agent * +struct agent* required_agent( const char *value ) { struct agent **pprev; - uint8_t len; - - for (len = 0 ; len < UINT8_MAX && value[len] ; len++) - if (value[len] == ':') - return search_agent(value, len, &pprev); - return 0; -} + size_t length; -static -void -async_call_agent( - struct agent *agent, - cyn_query_t *query, - const data_value_t *value -) { - int rc = agent->agent_cb( - agent->name, - agent->closure, - &query->key, - &value->value[agent->len + 1], - query); - if (rc < 0) - cyn_reply_query(query, value); + for (length = 0 ; length <= UINT8_MAX && value[length] ; length++) + if (value[length] == AGENT_SEPARATOR_CHARACTER) + return search_agent(value, length, &pprev); + return NULL; } +/** + * Allocates the query structure for handling the given parameters + * and return it. The query structure copies the key data to be compatible + * with asynchronous processing. + * + * @param on_result_cb the result callback to record + * @param closure the closure for the result callback + * @param key the key of the query + * @param maxdepth maximum depth of the agent subrequests + * @return the allocated structure or NULL in case of memory depletion + */ static cyn_query_t * alloc_query( @@ -420,6 +434,9 @@ alloc_query( ptr = &query[1]; query->on_result_cb = on_result_cb; query->closure = closure; + query->decount = maxdepth; + + /* copy strings of the key */ if (!key->client) query->key.client = 0; else { @@ -442,19 +459,13 @@ alloc_query( query->key.permission = 0; else { query->key.permission = ptr; - ptr = mempcpy(ptr, key->permission, szper); + mempcpy(ptr, key->permission, szper); } - query->decount = maxdepth; } return query; } - - - - - - +/* see cyn.h */ int cyn_query_async( on_result_cb_t *on_result_cb, @@ -463,25 +474,26 @@ cyn_query_async( int maxdepth ) { int rc; + unsigned score; data_value_t value; cyn_query_t *query; struct agent *agent; /* get the direct value */ - rc = db_test(key, &value); + score = db_test(key, &value); - /* on error or missing result */ - if (rc <= 0) { + /* missing value */ + if (score == 0) { default_value(&value); on_result_cb(closure, &value); - return rc; + return 0; } /* if not an agent or agent not required */ agent = required_agent(value.value); if (!agent || maxdepth <= 0) { on_result_cb(closure, &value); - return rc; + return 0; } /* allocate asynchronous query */ @@ -492,8 +504,15 @@ cyn_query_async( } /* call the agent */ - async_call_agent(agent, query, &value); - return 0; + rc = agent->agent_cb( + agent->name, + agent->closure, + &query->key, + &value.value[agent->len + 1], + query); + if (rc < 0) + cyn_query_reply(query, &value); + return rc; } /* see cyn.h */ @@ -516,8 +535,9 @@ cyn_check_async( return cyn_query_async(on_result_cb, closure, key, CYN_SEARCH_DEEP_MAX); } +/* see cyn.h */ int -cyn_subquery_async( +cyn_query_subquery_async( cyn_query_t *query, on_result_cb_t *on_result_cb, void *closure, @@ -526,8 +546,9 @@ cyn_subquery_async( return cyn_query_async(on_result_cb, closure, key, query->decount - 1); } +/* see cyn.h */ void -cyn_reply_query( +cyn_query_reply( cyn_query_t *query, const data_value_t *value ) { @@ -535,9 +556,28 @@ cyn_reply_query( free(query); } - - - +/** + * Check the name and compute its length. Returns 0 in case of invalid name + * @param name the name to check + * @return the length of the name or zero if invalid + */ +static +size_t +check_agent_name( + const char *name +) { + size_t length = 0; + if (name) { + while (name[length]) { + if (length > UINT8_MAX || name[length] == AGENT_SEPARATOR_CHARACTER) { + length = 0; + break; + } + length++; + } + } + return length; +} /* see cyn.h */ int @@ -548,26 +588,28 @@ cyn_agent_add( ) { struct agent *agent, **pprev; size_t length; - uint8_t len; - length = strlen(name); - if (length <= 0 || length > UINT8_MAX) + /* compute and check name length */ + length = check_agent_name(name); + if (!length) return -EINVAL; - len = (uint8_t)length++; - agent = search_agent(name, len, &pprev); + /* search the agent */ + agent = search_agent(name, length, &pprev); if (agent) return -EEXIST; - agent = malloc(sizeof *agent + length); + /* allocates the memory */ + agent = malloc(sizeof *agent + 1 + length); if (!agent) return -ENOMEM; + /* initialize the agent */ agent->next = 0; agent->agent_cb = agent_cb; agent->closure = closure; - agent->len = len; - memcpy(agent->name, name, length); + agent->len = (uint8_t)length; + memcpy(agent->name, name, length + 1); *pprev = agent; return 0; @@ -580,17 +622,18 @@ cyn_agent_remove( ) { struct agent *agent, **pprev; size_t length; - uint8_t len; - length = strlen(name); - if (length <= 0 || length > UINT8_MAX) + /* compute and check name length */ + length = check_agent_name(name); + if (!length) return -EINVAL; - len = (uint8_t)length; - agent = search_agent(name, len, &pprev); + /* search the agent */ + agent = search_agent(name, length, &pprev); if (!agent) return -ENOENT; + /* remove the found agent */ *pprev = agent->next; free(agent); return 0; @@ -600,14 +643,15 @@ cyn_agent_remove( void cyn_changeid_reset( ) { - last_changeid = 1; + changeid.current = 1; + changeid.instring = 0; } /* see cyn.h */ uint32_t cyn_changeid( ) { - return last_changeid; + return changeid.current; } /* see cyn.h */ @@ -615,9 +659,10 @@ const char * cyn_changeid_string( ) { /* regenerate the string on need */ - if (last_changeid != last_changeid_string) { - last_changeid_string = last_changeid; - snprintf(changeid_string, sizeof changeid_string, "%u", last_changeid); + if (changeid.current != changeid.instring) { + changeid.instring = changeid.current; + snprintf(changeid.string, sizeof changeid.string, "%u", changeid.current); } - return changeid_string; + /* return the string */ + return changeid.string; } |