beremiz

MQTT: fix bisection failing when topics start with same substring.

21 months ago, Edouard Tisserant
ab96d56f9ae9
Parents da52eabd0e6d
Children 9e4a3a3ea5c0
MQTT: fix bisection failing when topics start with same substring.
1 files changed, 30 insertions(+), 8 deletions(-)
  • +30 -8
    mqtt/mqtt_template.c
    • --- a/mqtt/mqtt_template.c Tue Sep 17 11:17:24 2024 +0200
    +++ b/mqtt/mqtt_template.c Thu Sep 19 12:05:35 2024 +0200
    @@ -134,17 +134,18 @@
    static pthread_t MQTT_thread;
    #define INIT_TOPIC(topic, iec_type, c_loc_name) \
    -{{#topic, &MQTT_##c_loc_name##_buf, &MQTT_##c_loc_name##_state, 0, .vartype = iec_type##_ENUM}},
    +{{#topic, sizeof(#topic)-1, &MQTT_##c_loc_name##_buf, &MQTT_##c_loc_name##_state, .is_json_type=0, .vartype = iec_type##_ENUM}},
    #define INIT_JSON_TOPIC(topic, iec_type, c_loc_name) \
    -{{#topic, &MQTT_##c_loc_name##_buf, &MQTT_##c_loc_name##_state, 1, .json_parse_func=json_parse_##c_loc_name}},
    +{{#topic, sizeof(#topic)-1, &MQTT_##c_loc_name##_buf, &MQTT_##c_loc_name##_state, .is_json_type=1, .json_parse_func=json_parse_##c_loc_name}},
    typedef int (*json_parse_func_t)(char *json, int len, void *void_ptr);
    static struct {{
    const char *topic; //null terminated topic string
    + const unsigned int topic_len;
    void *mqtt_pdata; // pointer to data from/for MQTT stack
    - int *mqtt_pchanged; // pointer to changed flag
    + int *mqtt_pstate; // pointer to changed flag
    int is_json_type;
    union {{
    __IEC_types_enum vartype;
    @@ -202,9 +203,30 @@
    // bisect topic among subscribed topics
    while (low <= high) {{
    - int res;
    + int res, len, delta_len;
    mid = low + (high - low) / 2;
    - res = strncmp(topics[mid].topic, topicName, topicLen);
    + if(topicLen == 0) {{
    + // zero topic len means null-terminated
    + topicLen = strlen(topicName);
    + }}
    +
    + len = topics[mid].topic_len;
    +
    + // keep track of length difference
    + delta_len = len - topicLen;
    +
    + // len = min(len, topicLen)
    + len = topicLen > len ? len : topicLen;
    +
    + // compare strings as far as possible
    + res = strncmp(topics[mid].topic, topicName, len);
    +
    + printf("%*s %s topic_len %d, delta_len %d, topicLen %d, len %d, res %d, low %d, mid %d, high %d\n", topicLen, topicName, topics[mid].topic, topics[mid].topic_len, delta_len, topicLen, len, res, low, mid, high);
    +
    + // if partial comparison matches, longest string is the greatest
    + if (res == 0)
    + // update res to continue bisection
    + res = delta_len;
    // Check if key is present at mid
    if (res == 0)
    @@ -219,20 +241,20 @@
    high = mid - 1;
    }}
    // If we reach here, then the element was not present
    - LogWarning("MQTT unknown topic: %s", topicName);
    + LogWarning("MQTT unknown topic: %s\n", topicName);
    goto exit;
    found:
    is_json_type = topics[mid].is_json_type;
    - if(is_json_type || __get_type_enum_size(topics[mid].vartype) == message->payloadlen){{
    + if(is_json_type || (__get_type_enum_size(topics[mid].vartype) == message->payloadlen)){{
    if (pthread_mutex_lock(&MQTT_retrieve_mutex) == 0){{
    if(is_json_type){{
    (topics[mid].json_parse_func)((char*)message->payload, message->payloadlen, topics[mid].mqtt_pdata);
    }} else {{
    memcpy(topics[mid].mqtt_pdata, (char*)message->payload, message->payloadlen);
    }}
    - *topics[mid].mqtt_pchanged = 1;
    + *topics[mid].mqtt_pstate = CHANGED;
    pthread_mutex_unlock(&MQTT_retrieve_mutex);
    }}
    }} else {{