Function JSON_read

src/iperf_api.c:3020–3078

/*************************************************************/

static cJSON *
JSON_read(int fd, int max_size)
{
    uint32_t hsize, nsize;
    size_t strsize;
    char *str;
    cJSON *json = NULL;
    int rc;
    char msg_buf[WARN_STR_LEN * 2];

    /*
     * Read a four-byte integer, which is the length of the JSON to follow.
     * Then read the JSON into a buffer and parse it.  Return a parsed JSON
     * structure, NULL if there was an error.
     */
    rc = Nread(fd, (char*) &nsize, sizeof(nsize), Ptcp);
    if (rc == sizeof(nsize)) {
        hsize = ntohl(nsize);
        if (hsize > 0 && (max_size == 0 || hsize <= max_size)) {
	    /* Allocate a buffer to hold the JSON */
	    strsize = hsize + 1;              /* +1 for trailing NULL */
	    if (strsize) {
	        str = (char *) calloc(sizeof(char), strsize);
	        if (str != NULL) {
	            rc = Nread(fd, str, hsize, Ptcp);
	            if (rc >= 0) {
                        /*
                        * We should be reading in the number of bytes corresponding to the
                        * length in that 4-byte integer.  If we don't the socket might have
                        * prematurely closed.  Only do the JSON parsing if we got the
                        * correct number of bytes.
                        */
                        if (rc == hsize) {
                            json = cJSON_Parse(str);
                        }
                        else {
                            snprintf(msg_buf, sizeof(msg_buf), "JSON size of data read does not correspond to offered length - expected %d bytes but received %d; errno=%d", hsize, rc, errno);
                            warning(msg_buf);
                        }
	            }
                    else {
                        snprintf(msg_buf, sizeof(msg_buf), "JSON data read failed; errno=%d", errno);
                        warning(msg_buf);
                    }
	            free(str);
                }
            }
	}
	else {
            snprintf(msg_buf, sizeof(msg_buf), "JSON data length overflow - %d bytes JSON size is not allowed", hsize);
	    warning(msg_buf);
	}
    }
    else {
        snprintf(msg_buf, sizeof(msg_buf), "Failed to read JSON data size - read returned %d; errno=%d", rc, errno);
        warning(msg_buf);
    }
    return json;