x5/khatus.c

   1 #include <sys/select.h>
   2 #include <sys/stat.h>
   3
   4 #include <assert.h>
   5 #include <ctype.h>
   6 #include <errno.h>
   7 #include <fcntl.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <time.h>
  12 #include <unistd.h>
  13
  14 #include <X11/Xlib.h>
  15
  16 #include "bsdtimespec.h"
  17 #include "khatus_lib_log.h"
  18 #include "khatus_lib_time.h"
  19
  20 #define usage(...) {print_usage(); fprintf(stderr, "Error:\n    " __VA_ARGS__); exit(EXIT_FAILURE);}
  21 #define ERRMSG "ERROR"
  22
  23 static const char errmsg[] = ERRMSG;
  24 static const int  errlen   = sizeof(ERRMSG) - 1;
  25
  26 char *argv0;
  27
  28 /* TODO: Convert fifo list to fifo array. */
  29 typedef struct Fifo Fifo;
  30 struct Fifo {
  31         char   *name;
  32         int     fd;
  33         int     width;
  34         int     last_read;
  35         int     ttl;
  36         int     pos_init;  /* Initial position on the output buffer. */
  37         int     pos_curr;  /* Current position on the output buffer. */
  38         int     pos_final; /* Final   position on the output buffer. */
  39         Fifo   *next;
  40 };
  41
  42 typedef struct Config Config;
  43 struct Config {
  44         double interval;
  45         char * separator;
  46         Fifo * fifos;
  47         int    fifo_count;
  48         int    total_width;
  49         int    output_to_x_root_window;
  50 } defaults = {
  51         .interval    = 1.0,
  52         .separator   = "|",
  53         .fifos       = NULL,
  54         .fifo_count  = 0,
  55         .total_width = 0,
  56         .output_to_x_root_window = 0,
  57 };
  58
  59 enum read_status {
  60         END_OF_FILE,
  61         END_OF_MESSAGE,
  62         RETRY,
  63         FAILURE
  64 };
  65
  66 void
  67 fifo_print_one(Fifo *f)
  68 {
  69         info("Fifo "
  70             "{"
  71             " name = %s,"
  72             " fd = %d,"
  73             " width = %d,"
  74             " last_read = %d,"
  75             " ttl = %d,"
  76             " pos_init = %d,"
  77             " pos_curr = %d,"
  78             " pos_final = %d,"
  79             " next = %p,"
  80             " }\n",
  81             f->name,
  82             f->fd,
  83             f->width,
  84             f->last_read,
  85             f->ttl,
  86             f->pos_init,
  87             f->pos_curr,
  88             f->pos_final,
  89             f->next
  90         );
  91 }
  92
  93 void
  94 fifo_print_all(Fifo *head)
  95 {
  96         for (Fifo *f = head; f; f = f->next) {
  97                 fifo_print_one(f);
  98         }
  99 }
 100
 101 void
 102 config_print(Config *cfg)
 103 {
 104         info(
 105             "Config "
 106             "{"
 107             " interval = %f,"
 108             " separator = %s,"
 109             " fifo_count = %d,"
 110             " total_width = %d,"
 111             " fifos = ..."
 112             " }\n",
 113             cfg->interval,
 114             cfg->separator,
 115             cfg->fifo_count,
 116             cfg->total_width
 117         );
 118         fifo_print_all(cfg->fifos);
 119 }
 120
 121 int
 122 is_pos_num(char *s)
 123 {
 124         while (*s != '\0')
 125                 if (!isdigit(*(s++)))
 126                         return 0;
 127         return 1;
 128 }
 129
 130 int
 131 is_decimal(char *s)
 132 {
 133         char c;
 134         int seen = 0;
 135
 136         while ((c = *(s++)) != '\0')
 137                 if (!isdigit(c)) {
 138                         if (c == '.' && !seen++)
 139                                 continue;
 140                         else
 141                                 return 0;
 142                 }
 143         return 1;
 144 }
 145
 146 void
 147 print_usage()
 148 {
 149         assert(argv0);
 150         fprintf(
 151             stderr,
 152             "\n"
 153             "Usage: %s [OPTION ...] SPEC [SPEC ...]\n"
 154             "\n"
 155             "  SPEC       = FILE_PATH DATA_WIDTH DATA_TTL\n"
 156             "  FILE_PATH  = string\n"
 157             "  DATA_WIDTH = int  (* (positive) number of characters *)\n"
 158             "  DATA_TTL   = int  (* (positive) number of seconds *)\n"
 159             "  OPTION     = -i INTERVAL\n"
 160             "             | -s SEPARATOR\n"
 161             "             | -x (* Output to X root window *)\n"
 162             "             | -l LOG_LEVEL\n"
 163             "  SEPARATOR  = string\n"
 164             "  INTERVAL   = int  (* (positive) number of seconds *)\n"
 165             "  LOG_LEVEL  = int  (* %d through %d *)\n"
 166             "\n",
 167             argv0,
 168             Nothing,
 169             Debug
 170         );
 171         fprintf(
 172             stderr,
 173             "Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n"
 174             "\n",
 175             argv0
 176         );
 177 }
 178
 179 void opts_parse_any(Config *, int, char *[], int);  /* For mutually-recursive calls. */
 180
 181 void
 182 parse_opts_opt_i(Config *cfg, int argc, char *argv[], int i)
 183 {
 184         char *param;
 185
 186         if (i >= argc)
 187                 usage("Option -i parameter is missing.\n");
 188         param = argv[i++];
 189         if (!is_decimal(param))
 190                 usage("Option -i parameter is invalid: \"%s\"\n", param);
 191         cfg->interval = atof(param);
 192         opts_parse_any(cfg, argc, argv, i);
 193 }
 194
 195 void
 196 parse_opts_opt_s(Config *cfg, int argc, char *argv[], int i)
 197 {
 198         if (i >= argc)
 199                 usage("Option -s parameter is missing.\n");
 200         cfg->separator = calloc((strlen(argv[i]) + 1), sizeof(char));
 201         strcpy(cfg->separator, argv[i]);
 202         opts_parse_any(cfg, argc, argv, ++i);
 203 }
 204
 205 void
 206 parse_opts_opt_l(Config *cfg, int argc, char *argv[], int i)
 207 {
 208         char *param;
 209         int log_level;
 210
 211         if (i >= argc)
 212                 usage("Option -l parameter is missing.\n");
 213         param = argv[i++];
 214         if (!is_pos_num(param))
 215                 usage("Option -l parameter is invalid: \"%s\"\n", param);
 216         log_level = atoi(param);
 217         if (log_level > Debug)
 218                 usage("Option -l value (%d) exceeds maximum (%d)\n", log_level, Debug);
 219         _khatus_lib_log_level = log_level;
 220         opts_parse_any(cfg, argc, argv, i);
 221 }
 222
 223 void
 224 parse_opts_opt(Config *cfg, int argc, char *argv[], int i)
 225 {
 226         switch (argv[i][1]) {
 227         case 'i':
 228                 /* TODO: Generic set_int */
 229                 parse_opts_opt_i(cfg, argc, argv, ++i);
 230                 break;
 231         case 's':
 232                 /* TODO: Generic set_str */
 233                 parse_opts_opt_s(cfg, argc, argv, ++i);
 234                 break;
 235         case 'x':
 236                 cfg->output_to_x_root_window = 1;
 237                 opts_parse_any(cfg, argc, argv, ++i);
 238                 break;
 239         case 'l':
 240                 /* TODO: Generic set_int */
 241                 parse_opts_opt_l(cfg, argc, argv, ++i);
 242                 break;
 243         default :
 244                 usage("Option \"%s\" is invalid\n", argv[i]);
 245         }
 246 }
 247
 248 void
 249 parse_opts_spec(Config *cfg, int argc, char *argv[], int i)
 250 {
 251         if ((i + 3) > argc)
 252                 usage("[spec] Parameter(s) missing for fifo \"%s\".\n", argv[i]);
 253
 254         char *n = argv[i++];
 255         char *w = argv[i++];
 256         char *t = argv[i++];
 257
 258         if (!is_pos_num(w))
 259                 usage("[spec] Invalid width: \"%s\", for fifo \"%s\"\n", w, n);
 260         if (!is_pos_num(t))
 261                 usage("[spec] Invalid TTL: \"%s\", for fifo \"%s\"\n", t, n);
 262         Fifo *f = calloc(1, sizeof(struct Fifo));
 263         if (f) {
 264                 f->name      = n;
 265                 f->fd        = -1;
 266                 f->width     = atoi(w);
 267                 f->ttl       = atoi(t);
 268                 f->last_read = 0;
 269                 f->pos_init  = cfg->total_width;
 270                 f->pos_curr  = f->pos_init;
 271                 f->pos_final = f->pos_init + f->width - 1;
 272                 f->next      = cfg->fifos;
 273
 274                 cfg->fifos        = f;
 275                 cfg->total_width += f->width;
 276                 cfg->fifo_count++;
 277         } else {
 278                 fatal("[memory] Allocation failure.");
 279         }
 280         opts_parse_any(cfg, argc, argv, i);
 281 }
 282
 283 void
 284 opts_parse_any(Config *cfg, int argc, char *argv[], int i)
 285 {
 286         if (i < argc) {
 287                 switch (argv[i][0]) {
 288                 case '-':
 289                         parse_opts_opt(cfg, argc, argv, i);
 290                         break;
 291                 default :
 292                         parse_opts_spec(cfg, argc, argv, i);
 293                 }
 294         }
 295 }
 296
 297 void
 298 opts_parse(Config *cfg, int argc, char *argv[])
 299 {
 300         opts_parse_any(cfg, argc, argv, 1);
 301
 302         Fifo *last = cfg->fifos;
 303         cfg->fifos = NULL;
 304         for (Fifo *f = last; f; ) {
 305                 Fifo *next = f->next;
 306                 f->next = cfg->fifos;
 307                 cfg->fifos = f;
 308                 f = next;
 309         }
 310 }
 311
 312 void
 313 fifo_read_error(Fifo *f, char *buf)
 314 {
 315         char *b;
 316         int i;
 317
 318         b = buf + f->pos_init;
 319         /* Copy as much of the error message as possible.
 320          * EXCLUDING the reminating \0. */
 321         for (i = 0; i < errlen && i < f->width; i++)
 322                 b[i] = errmsg[i];
 323         /* Any remaining slots: */
 324         for (; i < f->width; i++)
 325                 b[i] = '_';
 326 }
 327
 328 enum read_status
 329 fifo_read_one(Fifo *f, char *buf)
 330 {
 331         /* Initialize all to an impossible value: */
 332         ssize_t n = -5;  /* Number of bytes read. */
 333         char    c = -1;  /* Character read. */
 334         int     r = -1;  /* Remaining unused slots in buffer range. */
 335
 336         for (;;) {
 337                 n = read(f->fd, &c, 1);
 338                 assert(n >= -1 && n <= 1);
 339                 switch (n) {
 340                 case -1:
 341                         error("Failed to read: \"%s\". errno: %d, msg: %s\n",
 342                             f->name, errno, strerror(errno));
 343                         switch (errno) {
 344                         case EAGAIN:
 345                                 return RETRY;
 346                         default:
 347                                 return FAILURE;
 348                         }
 349                 case  0:
 350                         debug("%s: End of FILE\n", f->name);
 351                         f->pos_curr = f->pos_init;
 352                         return END_OF_FILE;
 353                 case  1:
 354                         /* TODO: Consider making msg term char a CLI option */
 355                         if (c == '\n' || c == '\0') {
 356                                 r = f->pos_final - f->pos_curr;
 357                                 if (r > 0)
 358                                         memset(buf + f->pos_curr, ' ', r);
 359                                 f->pos_curr = f->pos_init;
 360                                 return END_OF_MESSAGE;
 361                         } else {
 362                                 if (f->pos_curr <= f->pos_final)
 363                                         buf[f->pos_curr++] = c;
 364                                 /* Drop beyond available range. */
 365                         }
 366                         break;
 367                 default:
 368                         assert(0);
 369                 }
 370         }
 371         /* TODO Record timestamp read */
 372 }
 373
 374 void
 375 fifo_read_all(Config *cfg, char *buf)
 376 {
 377         fd_set fds;
 378         int maxfd = -1;
 379         int ready;
 380         struct stat st;
 381
 382         FD_ZERO(&fds);
 383         for (Fifo *f = cfg->fifos; f; f = f->next) {
 384                 /* TODO: Create the FIFO if it doesn't already exist. */
 385                 if (lstat(f->name, &st) < 0) {
 386                         error("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
 387                         fifo_read_error(f, buf);
 388                         continue;
 389                 }
 390                 if (!(st.st_mode & S_IFIFO)) {
 391                         error("\"%s\" is not a FIFO\n", f->name);
 392                         fifo_read_error(f, buf);
 393                         continue;
 394                 }
 395                 if (f->fd < 0) {
 396                         debug("%s: closed. opening. fd: %d\n", f->name, f->fd);
 397                         f->fd = open(f->name, O_RDONLY | O_NONBLOCK);
 398                 } else {
 399                         debug("%s: already openned. fd: %d\n", f->name, f->fd);
 400                 }
 401                 if (f->fd == -1) {
 402                         /* TODO: Consider backing off retries for failed fifos. */
 403                         error("Failed to open \"%s\"\n", f->name);
 404                         fifo_read_error(f, buf);
 405                         continue;
 406                 }
 407                 debug("%s: open. fd: %d\n", f->name, f->fd);
 408                 if (f->fd > maxfd)
 409                         maxfd = f->fd;
 410                 FD_SET(f->fd, &fds);
 411         }
 412         debug("selecting...\n");
 413         ready = select(maxfd + 1, &fds, NULL, NULL, NULL);
 414         debug("ready: %d\n", ready);
 415         assert(ready != 0);
 416         if (ready < 0)
 417                 fatal("%s", strerror(errno));
 418         for (Fifo *f = cfg->fifos; f; f = f->next) {
 419                 if (FD_ISSET(f->fd, &fds)) {
 420                         debug("reading: %s\n", f->name);
 421                         switch (fifo_read_one(f, buf)) {
 422                         case END_OF_FILE:
 423                         case FAILURE:
 424                                 close(f->fd);
 425                                 f->fd = -1;
 426                                 break;
 427                         case END_OF_MESSAGE:
 428                         case RETRY:
 429                                 break;
 430                         default:
 431                                 assert(0);
 432                         }
 433                 }
 434         }
 435 }
 436
 437 int
 438 main(int argc, char *argv[])
 439 {
 440         int width  = 0;
 441         int nfifos = 0;
 442         int seplen = 0;
 443         int prefix = 0;
 444         int errors = 0;
 445         char *buf;
 446         Config cfg0 = defaults;
 447         Config *cfg = &cfg0;
 448         Display *display = NULL;
 449         struct stat st;
 450         struct timespec
 451                 t0,  /* time stamp. before reading fifos */
 452                 t1,  /* time stamp. after  reading fifos */
 453                 ti,  /* time interval desired    (t1 - t0) */
 454                 td,  /* time interval measured   (t1 - t0) */
 455                 tc;  /* time interval correction (ti - td) when td < ti */
 456
 457         argv0 = argv[0];
 458
 459         opts_parse(cfg, argc, argv);
 460         debug("argv0 = %s\n", argv0);
 461         config_print(cfg);
 462
 463         ti = timespec_of_float(cfg->interval);
 464
 465         if (cfg->fifos == NULL)
 466                 usage("No fifo specs were given!\n");
 467
 468         /* 1st pass to check file existence and type */
 469         for (Fifo *f = cfg->fifos; f; f = f->next) {
 470                 if (lstat(f->name, &st) < 0) {
 471                         error("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
 472                         errors++;
 473                         continue;
 474                 }
 475                 if (!(st.st_mode & S_IFIFO)) {
 476                         error("\"%s\" is not a FIFO\n", f->name);
 477                         errors++;
 478                         continue;
 479                 }
 480         }
 481         if (errors)
 482                 fatal("Encountered errors with the given file paths. See log.\n");
 483
 484         width  = cfg->total_width;
 485         seplen = strlen(cfg->separator);
 486
 487         /* 2nd pass to make space for separators */
 488         for (Fifo *f = cfg->fifos; f; f = f->next) {
 489                 f->pos_init  += prefix;
 490                 f->pos_final += prefix;
 491                 f->pos_curr = f->pos_init;
 492                 prefix += seplen;
 493                 nfifos++;
 494         }
 495         width += (seplen * (nfifos - 1));
 496         buf = calloc(1, width + 1);
 497         if (buf == NULL)
 498                 fatal("[memory] Failed to allocate buffer of %d bytes", width);
 499         memset(buf, ' ', width);
 500         buf[width] = '\0';
 501         /* 3rd pass to set the separators */
 502         for (Fifo *f = cfg->fifos; f; f = f->next) {
 503                 if (f->pos_init) {  /* Skip the first, left-most */
 504                         /* Copying only seplen ensures we omit the '\0' byte. */
 505                         strncpy(buf + (f->pos_init - seplen), cfg->separator, seplen);
 506                 }
 507         }
 508
 509         if (cfg->output_to_x_root_window && !(display = XOpenDisplay(NULL)))
 510                 fatal("XOpenDisplay failed with: %p\n", display);
 511         /* TODO: Handle signals */
 512         for (;;) {
 513                 clock_gettime(CLOCK_MONOTONIC, &t0); // FIXME: check errors
 514                 /* TODO: Cache expiration. i.e. use the TTL */
 515                 /* TODO: How to trigger TTL check? On select? Alarm signal? */
 516                 /* TODO: Set timeout on fifo_read_all based on diff of last time of
 517                  *       fifo_read_all and desired time of next TTL check.
 518                  */
 519                 /* TODO: How long to wait on IO? Max TTL? */
 520                 fifo_read_all(cfg, buf);
 521                 if (cfg->output_to_x_root_window) {
 522                         if (XStoreName(display, DefaultRootWindow(display), buf) < 0)
 523                                 fatal("XStoreName failed.\n");
 524                         XFlush(display);
 525                 } else {
 526                         puts(buf);
 527                         fflush(stdout);
 528                 }
 529                 clock_gettime(CLOCK_MONOTONIC, &t1); // FIXME: check errors
 530                 timespecsub(&t1, &t0, &td);
 531                 debug("td {tv_sec = %ld, tv_nsec = %ld}\n", td.tv_sec, td.tv_nsec);
 532                 if (timespeccmp(&td, &ti, <)) {
 533                         /* Pushback on data producers by refusing to read the
 534                          * pipe more frequently than the interval.
 535                          */
 536                         timespecsub(&ti, &td, &tc);
 537                         debug("snooze YES\n");
 538                         snooze(&tc);
 539                 } else {
 540                         debug("snooze NO\n");
 541                 }
 542         }
 543
 544         return EXIT_SUCCESS;
 545 }