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