Method logging_loop

libraries/AP_GPS/GPS_Backend.cpp:491–532

logging loop, needs to be static to allow for re-alloc of GPS backends

// logging loop, needs to be static to allow for re-alloc of GPS backends
void AP_GPS_Backend::logging_loop(void)
{
    while (true) {
        hal.scheduler->delay(10);
        static uint16_t lognum;
        for (uint8_t instance=0; instance<2; instance++) {
            if (logging[instance].fd == -1 && logging[instance].buf.available()) {
                char fname[] = "gpsN_XXX.log";
                fname[3] = '1' + instance;
                if (lognum == 0) {
                    for (lognum=1; lognum<1000; lognum++) {
                        struct stat st;
                        hal.util->snprintf(&fname[5], 8, "%03u.log", lognum);
                        if (AP::FS().stat(fname, &st) != 0) {
                            break;
                        }
                    }
                }
                hal.util->snprintf(&fname[5], 8, "%03u.log", lognum);
                logging[instance].fd = AP::FS().open(fname, O_WRONLY|O_CREAT|O_APPEND);
            }
            if (logging[instance].fd != -1) {
                uint32_t n = 0;
                const uint8_t *p;
                while ((p = logging[instance].buf.readptr(n)) != nullptr && n != 0) {
                    struct {
                        uint32_t magic = 0x7fe53b04U;
                        uint32_t time_ms;
                        uint32_t n;
                    } header;
                    header.n = n;
                    header.time_ms = AP_HAL::millis();
                    // short writes are unlikely and are ignored (only FS full errors)
                    AP::FS().write(logging[instance].fd, (const uint8_t *)&header, sizeof(header));
                    AP::FS().write(logging[instance].fd, p, n);
                    logging[instance].buf.advance(n);
                    AP::FS().fsync(logging[instance].fd);
                }
            }
        }
    }
}

// logging thread start, needs to be non-static for thread_create
void AP_GPS_Backend::logging_start(void)