arexxd.c

   1 /*
   2  *      Linux Interfece for Arexx Data Loggers
   3  *
   4  *      (c) 2011-2012 Martin Mares <mj@ucw.cz>
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdarg.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <unistd.h>
  12 #include <fcntl.h>
  13 #include <math.h>
  14 #include <time.h>
  15 #include <getopt.h>
  16 #include <syslog.h>
  17 #include <signal.h>
  18 #include <sys/stat.h>
  19 #include <libusb-1.0/libusb.h>
  20 #include <rrd.h>
  21
  22 #define DEFAULT_LOG_DIR "/var/log/arexxd"
  23
  24 /*
  25  *  Data points received from the logger are sometimes corrupted by noise.
  26  *  This effects not only the measured values, but also sensor IDs and timestamps.
  27  *  Since rrdtool cannot skip back in time, a random timestamp in the future can
  28  *  cause all further measurements to be dropped. To minimize impact of these
  29  *  problems, we drop data points which are too far in the past or in the future.
  30  *
  31  *  Furthermore, you can ignore data from unrecognized sensors, i.e., those
  32  *  which are not handled by correct_point().
  33  */
  34 #define MAX_PAST_TIME 30*86400
  35 #define MAX_FUTURE_TIME 300
  36 #define IGNORE_UNKNOWN_SENSORS
  37
  38 typedef unsigned char byte;
  39 static libusb_context *usb_ctxt;
  40 static libusb_device_handle *devh;
  41
  42 static int use_syslog;
  43 static int debug_mode;
  44 static int debug_packets;
  45 static int debug_raw_data;
  46 static int debug_usb;
  47 static char *log_dir = DEFAULT_LOG_DIR;
  48 static int no_fork;
  49
  50 static void die(char *fmt, ...)
  51 {
  52         va_list args;
  53         va_start(args, fmt);
  54         if (use_syslog)
  55                 vsyslog(LOG_CRIT, fmt, args);
  56         else {
  57                 vfprintf(stderr, fmt, args);
  58                 fprintf(stderr, "\n");
  59         }
  60         va_end(args);
  61         exit(1);
  62 }
  63
  64 static void log_error(char *fmt, ...)
  65 {
  66         va_list args;
  67         va_start(args, fmt);
  68         if (use_syslog)
  69                 vsyslog(LOG_ERR, fmt, args);
  70         else {
  71                 vfprintf(stderr, fmt, args);
  72                 fprintf(stderr, "\n");
  73         }
  74         va_end(args);
  75 }
  76
  77 static void log_info(char *fmt, ...)
  78 {
  79         va_list args;
  80         va_start(args, fmt);
  81         if (use_syslog)
  82                 vsyslog(LOG_INFO, fmt, args);
  83         else {
  84                 vfprintf(stderr, fmt, args);
  85                 fprintf(stderr, "\n");
  86         }
  87         va_end(args);
  88 }
  89
  90 static void log_pkt(char *fmt, ...)
  91 {
  92         if (!debug_packets)
  93                 return;
  94         va_list args;
  95         va_start(args, fmt);
  96         vprintf(fmt, args);
  97         va_end(args);
  98 }
  99
 100 /*** RRD interface ***/
 101
 102 #define MAX_ARGS 20
 103 #define MAX_ARG_SIZE 1024
 104
 105 static int arg_cnt;
 106 static char *arg_ptr[MAX_ARGS+1];
 107 static char arg_buf[MAX_ARG_SIZE];
 108 static int arg_pos;
 109
 110 static void arg_new(void)
 111 {
 112         arg_cnt = 1;
 113         arg_pos = 0;
 114         arg_ptr[0] = "rrdtool";
 115 }
 116
 117 static void arg_push(const char *fmt, ...)
 118 {
 119         if (arg_cnt >= MAX_ARGS)
 120                 die("MAX_ARGS exceeded");
 121         va_list va;
 122         va_start(va, fmt);
 123         int len = 1 + vsnprintf(arg_buf + arg_pos, MAX_ARG_SIZE - arg_pos, fmt, va);
 124         if (arg_pos + len > MAX_ARG_SIZE)
 125                 die("MAX_ARG_SIZE exceeded");
 126         arg_ptr[arg_cnt++] = arg_buf + arg_pos;
 127         arg_ptr[arg_cnt] = NULL;
 128         arg_pos += len;
 129 }
 130
 131 static void rrd_point(time_t t, const char *name, double val, char *unit)
 132 {
 133         char rr_name[256];
 134         snprintf(rr_name, sizeof(rr_name), "sensor-%s.rrd", name);
 135
 136         struct stat st;
 137         if (stat(rr_name, &st) < 0 || !st.st_size) {
 138                 // We have to create the RRD
 139                 log_info("Creating %s", rr_name);
 140                 arg_new();
 141                 arg_push(rr_name);
 142                 arg_push("--start");
 143                 arg_push("%d", (int) time(NULL) - 28*86400);
 144                 arg_push("--step");
 145                 arg_push("60");
 146                 if (!strcmp(unit, "%RH"))
 147                         arg_push("DS:rh:GAUGE:300:0:100");
 148                 else if (!strcmp(unit, "ppm"))
 149                         arg_push("DS:ppm:GAUGE:300:0:1000000");
 150                 else
 151                         arg_push("DS:temp:GAUGE:300:-200:200");
 152                 arg_push("RRA:AVERAGE:0.25:1:20160");           // Last 14 days with full resolution
 153                 arg_push("RRA:AVERAGE:0.25:60:88800");          // Last 10 years with 1h resolution
 154                 arg_push("RRA:MIN:0.25:60:88800");              // including minima and maxima
 155                 arg_push("RRA:MAX:0.25:60:88800");
 156                 rrd_create(arg_cnt, arg_ptr);
 157                 if (rrd_test_error()) {
 158                         log_error("rrd_create on %s failed: %s", rr_name, rrd_get_error());
 159                         rrd_clear_error();
 160                         return;
 161                 }
 162         }
 163
 164         arg_new();
 165         arg_push(rr_name);
 166         arg_push("%d:%f", t, val);
 167         rrd_update(arg_cnt, arg_ptr);
 168         if (rrd_test_error()) {
 169                 log_error("rrd_update on %s failed: %s", rr_name, rrd_get_error());
 170                 rrd_clear_error();
 171         }
 172 }
 173
 174 /*** Transforms ***/
 175
 176 #define TIME_OFFSET 946681200           // Timestamp of 2000-01-01 00:00:00
 177
 178 static int data_point_counter;          // Since last log message
 179 static time_t packet_rx_time;
 180
 181 static double correct_point(int id, double val, const char **name)
 182 {
 183         /*
 184          *  Manually calculated corrections and renames for my sensors.
 185          *  Replace with your formulae.
 186          */
 187         switch (id) {
 188                 case 10415:
 189                         *name = "ursarium";
 190                         return val - 0.93;
 191                 case 10707:
 192                         *name = "balcony";
 193                         return val - 0.71;
 194                 case 11699:
 195                         *name = "outside";
 196                         return val;
 197                 case 19246:
 198                         *name = "catarium";
 199                         return val + 0.49;
 200                 case 19247:
 201                         *name = "catarium-rh";
 202                         return val;
 203                 case 12133:
 204                         *name = "aquarium";
 205                         return val + 0.44;
 206                 default:
 207 #ifdef IGNORE_UNKNOWN_SENSORS
 208                         *name = NULL;
 209 #endif
 210                         return val;
 211         }
 212 }
 213
 214 static void cooked_point(time_t t, int id, double val, char *unit, int q)
 215 {
 216         char namebuf[16];
 217         snprintf(namebuf, sizeof(namebuf), "%d", id);
 218         const char *name = namebuf;
 219
 220         double val2 = correct_point(id, val, &name);
 221
 222         if (debug_raw_data) {
 223                 struct tm tm;
 224                 localtime_r(&t, &tm);
 225                 char tbuf[64];
 226                 strftime(tbuf, sizeof(tbuf), "%Y-%m-%d %H:%M:%S", &tm);
 227                 printf("== %s id=%d name=%s val=%.3f val2=%.3f unit=%s q=%d\n", tbuf, id, name, val, val2, unit, q);
 228         }
 229
 230         if (!name) {
 231                 log_error("Ignored data from unknown sensor %d", id);
 232                 return;
 233         }
 234         if (t < packet_rx_time - MAX_PAST_TIME) {
 235                 log_error("Data point from sensor %d too far in the past (%d sec)", packet_rx_time - t);
 236                 return;
 237         }
 238         if (t > packet_rx_time + MAX_FUTURE_TIME) {
 239                 log_error("Data point from sensor %d too far in the future (%d sec)", t - packet_rx_time);
 240                 return;
 241         }
 242
 243         data_point_counter++;
 244         rrd_point(t, name, val2, unit);
 245 }
 246
 247 static void raw_point(int t, int id, int raw, int q)
 248 {
 249         /*
 250          *  The binary blob provided by Arexx contains an embedded XML fragment
 251          *  with descriptions of all known sensor types. If you want to see it,
 252          *  grep the blob for "<deviceinfo>". The meanings of the parameters are
 253          *  as follows:
 254          *
 255          *      m1, m2          Device type matches if (raw_sensor_id & m1) == m2
 256          *      type            Unit measured by the sensor (1=Celsius, 2=RH%, 3=CO2 ppm)
 257          *      dm              User-visible sensor ID = raw_sensor_id & dm
 258          *      i               1 if the raw value is signed
 259          *      p[]             Coefficients of transformation polynomial (x^0 first)
 260          *      vLo, vUp        Upper and lower bound on the final value
 261          *      scale           Scaling function:
 262          *                              0 = identity (default)
 263          *                              1 = 10^x
 264          *                              2 = exp(x)
 265          *                              3 = (x < 0) ? 0 : log10(x)
 266          *                              4 = (x < 0) ? 0 : log(x)
 267          *
 268          *  The raw values are transformed this way:
 269          *      - sign-extend if signed
 270          *      - apply the transformation polynomial
 271          *      - apply the scaling function
 272          *      - drop if outside the interval [vLo,vUp]
 273          *
 274          *  This function applies the necessary transform for sensors we've
 275          *  seen in the wild. We deliberately ignore the "dm" parameter as we want
 276          *  to report different channels of a single sensor as multiple sensors.
 277          */
 278
 279         double z = raw;
 280         double hi, lo;
 281         char *unit;
 282         int idhi = id & 0xf000;
 283
 284         if (idhi == 0x1000) {
 285                 z = 0.02*z - 273.15;
 286                 lo = -200;
 287                 hi = 600;
 288                 unit = "C";
 289         } else if (idhi == 0x2000) {
 290                 if (raw >= 0x8000)
 291                         z -= 0x10000;
 292                 z /= 128;
 293                 lo = -60;
 294                 hi = 125;
 295                 unit = "C";
 296         } else if (idhi == 0x4000) {
 297                 if (!(id & 1)) {
 298                         z = z/100 - 39.6;
 299                         lo = -60;
 300                         hi = 125;
 301                         unit = "C";
 302                 } else {
 303                         z = -2.8e-6*z*z + 0.0405*z - 4;
 304                         lo = 0;
 305                         hi = 100.1;
 306                         unit = "%RH";
 307                 }
 308         } else if (idhi == 0x6000) {
 309                 if (!(id & 1)) {
 310                         if (raw >= 0x8000)
 311                                 z -= 0x10000;
 312                         z /= 128;
 313                         lo = -60;
 314                         hi = 125;
 315                         unit = "C";
 316                 } else {
 317                         z = -3.8123e-11*z;
 318                         z = (z + 1.9184e-7) * z;
 319                         z = (z - 1.0998e-3) * z;
 320                         z += 6.56;
 321                         z = pow(10, z);
 322                         lo = 0;
 323                         hi = 1e6;
 324                         unit = "ppm";
 325                 }
 326         } else {
 327                 log_error("Unknown sensor type 0x%04x", id);
 328                 return;
 329         }
 330
 331         if (z < lo || z > hi) {
 332                 log_error("Sensor %d: value %f out of range", id, z);
 333                 return;
 334         }
 335
 336         cooked_point(t + TIME_OFFSET, id, z, unit, q);
 337 }
 338
 339 /*** USB interface ***/
 340
 341 static int rx_endpoint, tx_endpoint;
 342
 343 static int parse_descriptors(libusb_device *dev)
 344 {
 345         int err;
 346         struct libusb_config_descriptor *desc;
 347
 348         if (err = libusb_get_active_config_descriptor(dev, &desc)) {
 349                 log_error("libusb_get_config_descriptor failed: error %d", err);
 350                 return 0;
 351         }
 352         if (desc->bNumInterfaces != 1) {
 353                 log_error("Unexpected number of interfaces: %d", desc->bNumInterfaces);
 354                 goto failed;
 355         }
 356
 357         const struct libusb_interface *iface = &desc->interface[0];
 358         if (iface->num_altsetting != 1) {
 359                 log_error("Unexpected number of alternate interface settings: %d", iface->num_altsetting);
 360                 goto failed;
 361         }
 362
 363         const struct libusb_interface_descriptor *ifd = &iface->altsetting[0];
 364         if (ifd->bNumEndpoints != 2) {
 365                 log_error("Unexpected number of endpoints: %d", ifd->bNumEndpoints);
 366                 goto failed;
 367         }
 368
 369         rx_endpoint = tx_endpoint = -1;
 370         for (int i=0; i<2; i++) {
 371                 const struct libusb_endpoint_descriptor *epd = &ifd->endpoint[i];
 372                 if (epd->bEndpointAddress & 0x80)
 373                         rx_endpoint = epd->bEndpointAddress;
 374                 else
 375                         tx_endpoint = epd->bEndpointAddress;
 376         }
 377         if (rx_endpoint < 0 || tx_endpoint < 0) {
 378                 log_error("Failed to identify endpoints");
 379                 goto failed;
 380         }
 381
 382         log_pkt("Found endpoints: rx==%02x tx=%02x\n", rx_endpoint, tx_endpoint);
 383         libusb_free_config_descriptor(desc);
 384         return 1;
 385
 386 failed:
 387         libusb_free_config_descriptor(desc);
 388         return 0;
 389 }
 390
 391 static int find_device(void)
 392 {
 393         libusb_device **devlist;
 394         ssize_t devn = libusb_get_device_list(usb_ctxt, &devlist);
 395         if (devn < 0) {
 396                 log_error("Cannot enumerate USB devices: error %d", (int) devn);
 397                 return 0;
 398         }
 399
 400         for (ssize_t i=0; i<devn; i++) {
 401                 struct libusb_device_descriptor desc;
 402                 libusb_device *dev = devlist[i];
 403                 if (!libusb_get_device_descriptor(dev, &desc)) {
 404                         if (desc.idVendor == 0x0451 && desc.idProduct == 0x3211) {
 405                                 log_info("Arexx data logger found at usb%d.%d", libusb_get_bus_number(dev), libusb_get_device_address(dev));
 406                                 if (!parse_descriptors(dev))
 407                                         continue;
 408                                 int err;
 409                                 if (err = libusb_open(dev, &devh)) {
 410                                         log_error("libusb_open() failed: error %d", err);
 411                                         goto failed;
 412                                 }
 413                                 if (err = libusb_claim_interface(devh, 0)) {
 414                                         log_error("libusb_claim_interface() failed: error %d", err);
 415                                         libusb_close(devh);
 416                                         goto failed;
 417                                 }
 418                                 libusb_free_device_list(devlist, 1);
 419                                 return 1;
 420                         }
 421                 }
 422         }
 423
 424 failed:
 425         libusb_free_device_list(devlist, 1);
 426         return 0;
 427 }
 428
 429 static void release_device(void)
 430 {
 431         libusb_release_interface(devh, 0);
 432         libusb_reset_device(devh);
 433         libusb_close(devh);
 434         devh = NULL;
 435 }
 436
 437 static void dump_packet(byte *pkt)
 438 {
 439         for (int i=0; i<64; i++) {
 440                 if (!(i % 16))
 441                         log_pkt("\t%02x:", i);
 442                 log_pkt(" %02x", pkt[i]);
 443                 if (i % 16 == 15)
 444                         log_pkt("\n");
 445         }
 446 }
 447
 448 static void my_msleep(int ms)
 449 {
 450         struct timespec ts = { .tv_sec = ms/1000, .tv_nsec = (ms%1000) * 1000000 };
 451         nanosleep(&ts, NULL);
 452 }
 453
 454 static int send_and_receive(byte *req, byte *reply)
 455 {
 456         if (debug_packets) {
 457                 time_t t = time(NULL);
 458                 struct tm tm;
 459                 localtime_r(&t, &tm);
 460
 461                 char tbuf[64];
 462                 strftime(tbuf, sizeof(tbuf), "%Y-%m-%d %H:%M:%S", &tm);
 463                 log_pkt("## %s\n", tbuf);
 464         }
 465
 466         int err, transferred;
 467         if (err = libusb_bulk_transfer(devh, tx_endpoint, req, 64, &transferred, 200)) {
 468                 if (err == LIBUSB_ERROR_TIMEOUT) {
 469                         log_pkt(">> xmit timed out\n");
 470                         return 0;
 471                 }
 472                 log_pkt(">> xmit error %d\n", err);
 473                 log_error("Transmit error: %d", err);
 474                 return err;
 475         }
 476         if (debug_packets) {
 477                 log_pkt(">> xmit %d bytes\n", transferred);
 478                 dump_packet(req);
 479         }
 480         my_msleep(1);
 481         if (err = libusb_bulk_transfer(devh, rx_endpoint, reply, 64, &transferred, 200)) {
 482                 if (err == LIBUSB_ERROR_TIMEOUT) {
 483                         log_pkt("<< recv timed out\n");
 484                         return 0;
 485                 }
 486                 log_pkt("<< recv error %d\n", err);
 487                 log_error("Receive error: %d", err);
 488                 return err;
 489         }
 490         packet_rx_time = time(NULL);
 491         if (debug_packets)
 492                 log_pkt("<< recv %d bytes\n", transferred);
 493         while (transferred < 64)
 494                 reply[transferred++] = 0xff;
 495         if (debug_packets)
 496                 dump_packet(reply);
 497         return 1;
 498 }
 499
 500 static unsigned int get_be16(byte *p)
 501 {
 502         return p[1] | (p[0] << 8);
 503 }
 504
 505 static unsigned int get_le16(byte *p)
 506 {
 507         return p[0] | (p[1] << 8);
 508 }
 509
 510 static unsigned int get_le32(byte *p)
 511 {
 512         return get_le16(p) | (get_le16(p+2) << 16);
 513 }
 514
 515 static void put_le16(byte *p, unsigned int x)
 516 {
 517         p[0] = x;
 518         p[1] = x >> 8;
 519 }
 520
 521 static void put_le32(byte *p, unsigned int x)
 522 {
 523         put_le16(p, x);
 524         put_le16(p+2, x>>16);
 525 }
 526
 527 static int parse_packet(byte *reply)
 528 {
 529         if (reply[0]) {
 530                 log_error("Unknown packet type %02x", reply[0]);
 531                 return 0;
 532         }
 533
 534         int pos = 1;
 535         int points = 0;
 536         while (pos < 64) {
 537                 byte *p = reply + pos;
 538                 int len = p[0];
 539                 if (!len || len == 0xff)
 540                         break;
 541                 if (len < 9 || len > 10) {
 542                         log_error("Unknown tuple length %02x", len);
 543                         break;
 544                 }
 545                 if (pos + len > 64) {
 546                         log_error("Tuple truncated");
 547                         break;
 548                 }
 549                 int id = get_le16(p+1);
 550                 int raw = get_be16(p+3);
 551                 int t = get_le32(p+5);
 552                 int q = (len > 9) ? p[9] : -1;
 553                 if (debug_raw_data) {
 554                         printf("... %02x: id=%d raw=%d t=%d", len, id, raw, t);
 555                         if (len > 9)
 556                                 printf(" q=%d", q);
 557                         printf("\n");
 558                 }
 559                 raw_point(t, id, raw, q);
 560                 pos += len;
 561                 points++;
 562         }
 563
 564         return points;
 565 }
 566
 567 static void set_clock(void)
 568 {
 569         byte req[64], reply[64];
 570         memset(req, 0, 64);
 571         req[0] = 4;
 572         time_t t = time(NULL);
 573         put_le32(req+1, t-TIME_OFFSET);
 574         send_and_receive(req, reply);
 575
 576 #if 0
 577         /*
 578          *  Original software also sends a packet with type 3 and the timestamp,
 579          *  but it does not make any sense, especially as they ignore the sensor
 580          *  readings in the answer.
 581          */
 582         req[0] = 3;
 583         send_and_receive(req, reply);
 584         parse_packet(reply);
 585 #endif
 586 }
 587
 588 /*** Main ***/
 589
 590 static sigset_t term_sigs;
 591 static volatile sig_atomic_t want_shutdown;
 592
 593 static void sigterm_handler(int sig __attribute__((unused)))
 594 {
 595         want_shutdown = 1;
 596 }
 597
 598 static void interruptible_msleep(int ms)
 599 {
 600         sigprocmask(SIG_UNBLOCK, &term_sigs, NULL);
 601         my_msleep(ms);
 602         sigprocmask(SIG_BLOCK, &term_sigs, NULL);
 603 }
 604
 605 static const struct option long_options[] = {
 606         { "debug",              0, NULL, 'd' },
 607         { "log-dir",            1, NULL, 'l' },
 608         { "no-fork",            0, NULL, 'n' },
 609         { "debug-packets",      0, NULL, 'p' },
 610         { "debug-raw",          0, NULL, 'r' },
 611         { "version",            0, NULL, 'V' },
 612         { NULL,                 0, NULL, 0 },
 613 };
 614
 615 static void usage(void)
 616 {
 617         fprintf(stderr, "\n\
 618 Usage: arexxd <options>\n\
 619 \n\
 620 Options:\n\
 621 -d, --debug             Debug mode (no chdir, no fork, no syslog)\n\
 622 -l, --log-dir=<dir>     Directory where all received data should be stored\n\
 623 -n, --no-fork           Do not fork\n\
 624 -p, --debug-packets     Log all packets sent and received\n\
 625 -r, --debug-raw         Log conversion from raw values\n\
 626 -u, --debug-usb         Enable libusb debug messages (to stdout/stderr)\n\
 627 -V, --version           Show daemon version\n\
 628 ");
 629         exit(1);
 630 }
 631
 632 int main(int argc, char **argv)
 633 {
 634         int opt;
 635         while ((opt = getopt_long(argc, argv, "dl:npruV", long_options, NULL)) >= 0)
 636                 switch (opt) {
 637                         case 'd':
 638                                 debug_mode++;
 639                                 break;
 640                         case 'l':
 641                                 log_dir = optarg;
 642                                 break;
 643                         case 'n':
 644                                 no_fork++;
 645                                 break;
 646                         case 'p':
 647                                 debug_packets++;
 648                                 break;
 649                         case 'r':
 650                                 debug_raw_data++;
 651                                 break;
 652                         case 'u':
 653                                 debug_usb++;
 654                                 break;
 655                         case 'V':
 656                                 printf("arexxd " AREXXD_VERSION "\n");
 657                                 printf("(c) 2011-2012 Martin Mares <mj@ucw.cz>\n");
 658                                 return 0;
 659                         default:
 660                                 usage();
 661                 }
 662         if (optind < argc)
 663                 usage();
 664
 665         int err;
 666         if (err = libusb_init(&usb_ctxt))
 667                 die("Cannot initialize libusb: error %d", err);
 668         if (debug_usb)
 669                 libusb_set_debug(usb_ctxt, 3);
 670
 671         if (!debug_mode) {
 672                 if (chdir(log_dir) < 0)
 673                         die("Cannot change directory to %s: %m", log_dir);
 674                 if (debug_packets || debug_raw_data) {
 675                         close(1);
 676                         if (open("debug", O_WRONLY | O_CREAT | O_APPEND, 0666) < 0)
 677                                 die("Cannot open debug log: %m");
 678                         setlinebuf(stdout);
 679                 }
 680                 openlog("arexxd", LOG_NDELAY, LOG_DAEMON);
 681                 if (!no_fork) {
 682                         pid_t pid = fork();
 683                         if (pid < 0)
 684                                 die("fork() failed: %m");
 685                         if (pid)
 686                                 return 0;
 687                 }
 688                 setsid();
 689                 use_syslog = 1;
 690         }
 691
 692         struct sigaction sa = { .sa_handler = sigterm_handler };
 693         sigaction(SIGTERM, &sa, NULL);
 694         sigaction(SIGINT, &sa, NULL);
 695
 696         sigemptyset(&term_sigs);
 697         sigaddset(&term_sigs, SIGTERM);
 698         sigaddset(&term_sigs, SIGINT);
 699         sigprocmask(SIG_BLOCK, &term_sigs, NULL);
 700
 701         int inited = 0;
 702         while (!want_shutdown) {
 703                 if (!find_device()) {
 704                         if (!inited) {
 705                                 inited = 1;
 706                                 log_error("Data logger not connected, waiting until it appears");
 707                         }
 708                         interruptible_msleep(30000);
 709                         continue;
 710                 }
 711                 log_info("Listening");
 712
 713                 time_t last_sync = 0;
 714                 time_t last_show = 0;
 715                 int want_stats = 0;
 716                 int want_sleep = 0;
 717                 data_point_counter = 0;
 718                 while (!want_shutdown) {
 719                         time_t now = time(NULL);
 720                         if (now > last_sync + 900) {
 721                                 log_info("Synchronizing data logger time");
 722                                 set_clock();
 723                                 last_sync = now;
 724                         }
 725                         if (want_stats && now > last_show + 300) {
 726                                 log_info("Stats: received %d data points", data_point_counter);
 727                                 data_point_counter = 0;
 728                                 last_show = now;
 729                         }
 730
 731                         byte req[64], reply[64];
 732                         memset(req, 0, sizeof(req));
 733                         req[0] = 3;
 734                         err = send_and_receive(req, reply);
 735                         if (err < 0)
 736                                 break;
 737                         want_sleep = 1;
 738                         if (err > 0 && parse_packet(reply))
 739                                 want_sleep = 0;
 740                         if (want_sleep) {
 741                                 interruptible_msleep(4000);
 742                                 want_stats = 1;
 743                         } else
 744                                 interruptible_msleep(5);
 745                 }
 746
 747                 log_info("Disconnecting data logger");
 748                 release_device();
 749                 inited = 0;
 750                 interruptible_msleep(10000);
 751         }
 752
 753         log_info("Terminated");
 754         return 0;
 755 }