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