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 <unistd.h>
  12
  13 #include <X11/Xlib.h>
  14
  15 #define debug(args...) {fprintf(stderr, "[debug] " args);}
  16 #define info( args...) {fprintf(stderr, "[info] "  args);}
  17 #define error(args...) {fprintf(stderr, "[error] " args);}
  18 #define fatal(args...) {fprintf(stderr, "[fatal] " args); exit(EXIT_FAILURE);}
  19 #define usage(args...) {print_usage(); fatal("[usage] " args);}
  20
  21 char *argv0;
  22
  23 /* TODO: Convert fifo list to fifo array. */
  24 typedef struct Fifo Fifo;
  25 struct Fifo {
  26         char   *name;
  27         int     fd;
  28         int     width;
  29         int     last_read;
  30         int     ttl;
  31         int     pos;  /* Position on the output buffer. */
  32         Fifo   *next;
  33 };
  34
  35 typedef struct Config Config;
  36 struct Config {
  37         int    interval;
  38         char * separator;
  39         Fifo * fifos;
  40         int    fifo_count;
  41         int    total_width;
  42         int    output_to_x_root_window;
  43 } defaults = {
  44         .interval    = 1,
  45         .separator   = "|",
  46         .fifos       = NULL,
  47         .fifo_count  = 0,
  48         .total_width = 0,
  49         .output_to_x_root_window = 0,
  50 };
  51
  52 void
  53 fifo_print_one(Fifo *f)
  54 {
  55         debug(
  56                 "Fifo "
  57                 "{"
  58                         " name = %s,"
  59                         " fd = %d,"
  60                         " width = %d,"
  61                         " last_read = %d,"
  62                         " ttl = %d,"
  63                         " pos = %d,"
  64                         " next = %p,"
  65                 " }\n",
  66                 f->name,
  67                 f->fd,
  68                 f->width,
  69                 f->last_read,
  70                 f->ttl,
  71                 f->pos,
  72                 f->next
  73         );
  74 }
  75
  76 void
  77 fifo_print_all(Fifo *head)
  78 {
  79         for (Fifo *f = head; f; f = f->next) {
  80                 fifo_print_one(f);
  81         }
  82 }
  83
  84 void
  85 config_print(Config *c)
  86 {
  87         debug(
  88                 "Config "
  89                 "{"
  90                         " interval = %d,"
  91                         " separator = %s,"
  92                         " fifo_count = %d,"
  93                         " total_width = %d,"
  94                         " fifos = ..."
  95                 " }\n",
  96                 c->interval,
  97                 c->separator,
  98                 c->fifo_count,
  99                 c->total_width
 100         );
 101         fifo_print_all(c->fifos);
 102 }
 103
 104 int
 105 is_pos_num(char *s)
 106 {
 107         while (*s != '\0')
 108                 if (!isdigit(*(s++)))
 109                         return 0;
 110         return 1;
 111 }
 112
 113 void
 114 print_usage()
 115 {
 116         assert(argv0);
 117         fprintf(
 118                 stderr,
 119                 "\n"
 120                 "Usage: %s [OPTION ...] SPEC [SPEC ...]\n"
 121                 "\n"
 122                 "  SPEC       = FILE_PATH DATA_WIDTH DATA_TTL\n"
 123                 "  FILE_PATH  = string\n"
 124                 "  DATA_WIDTH = int  (* (positive) number of characters *)\n"
 125                 "  DATA_TTL   = int  (* (positive) number of seconds *)\n"
 126                 "  OPTION     = -i INTERVAL\n"
 127                 "             | -s SEPARATOR\n"
 128                 "  SEPARATOR  = string\n"
 129                 "  INTERVAL   = int  (* (positive) number of seconds *)\n"
 130                 "\n",
 131                 argv0
 132         );
 133         fprintf(
 134                 stderr,
 135                 "Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n"
 136                 "\n",
 137                 argv0
 138         );
 139 }
 140
 141 void opts_parse_any(Config *, int, char *[], int);  /* For mutually-recursive calls. */
 142
 143 void
 144 parse_opts_opt_i(Config *cfg, int argc, char *argv[], int i)
 145 {
 146         if (i < argc) {
 147                 char *param = argv[i++];
 148
 149                 if (is_pos_num(param)) {
 150                         cfg->interval = atoi(param);
 151                         opts_parse_any(cfg, argc, argv, i);
 152                 } else {
 153                         usage("Option -i parameter is invalid: \"%s\"\n", param);
 154                 }
 155         } else {
 156                 usage("Option -i parameter is missing.\n");
 157         }
 158 }
 159
 160 void
 161 parse_opts_opt_s(Config *cfg, int argc, char *argv[], int i)
 162 {
 163         if (i < argc) {
 164                 cfg->separator = calloc((strlen(argv[i]) + 1), sizeof(char));
 165                 strcpy(cfg->separator, argv[i]);
 166                 opts_parse_any(cfg, argc, argv, ++i);
 167         } else {
 168                 usage("Option -s parameter is missing.\n");
 169         }
 170 }
 171
 172 void
 173 parse_opts_opt(Config *cfg, int argc, char *argv[], int i)
 174 {
 175         switch (argv[i][1]) {
 176                 case 'i': parse_opts_opt_i(cfg, argc, argv, ++i); break;  /* TODO: Generic set_int */
 177                 case 's': parse_opts_opt_s(cfg, argc, argv, ++i); break;  /* TODO: Generic set_str */
 178                 case 'x': {
 179                         cfg->output_to_x_root_window = 1;
 180                         opts_parse_any(cfg, argc, argv, ++i);
 181                         break;
 182                 }
 183                 default : usage("Option \"%s\" is invalid\n", argv[i]);
 184         }
 185 }
 186
 187 void
 188 parse_opts_spec(Config *cfg, int argc, char *argv[], int i)
 189 {
 190         if ((i + 3) > argc)
 191                 usage("[spec] Parameter(s) missing for fifo \"%s\".\n", argv[i]);
 192
 193         char *n = argv[i++];
 194         char *w = argv[i++];
 195         char *t = argv[i++];
 196
 197         if (!is_pos_num(w))
 198                 usage("[spec] Invalid width: \"%s\", for fifo \"%s\"\n", w, n);
 199         if (!is_pos_num(t))
 200                 usage("[spec] Invalid TTL: \"%s\", for fifo \"%s\"\n", t, n);
 201         Fifo *f = calloc(1, sizeof(struct Fifo));
 202         if (f) {
 203                 f->name      = n;
 204                 f->fd        = -1;
 205                 f->width     = atoi(w);
 206                 f->ttl       = atoi(t);
 207                 f->last_read = 0;
 208                 f->pos       = cfg->total_width;
 209                 f->next      = cfg->fifos;
 210
 211                 cfg->fifos        = f;
 212                 cfg->total_width += f->width;
 213                 cfg->fifo_count++;
 214         } else {
 215                 fatal("[memory] Allocation failure.");
 216         }
 217         opts_parse_any(cfg, argc, argv, i);
 218 }
 219
 220 void
 221 opts_parse_any(Config *cfg, int argc, char *argv[], int i)
 222 {
 223         if (i < argc) {
 224                 switch (argv[i][0]) {
 225                         case '-': parse_opts_opt(cfg, argc, argv, i); break;
 226                         default : parse_opts_spec(cfg, argc, argv, i);
 227                 }
 228         }
 229 }
 230
 231 void
 232 opts_parse(Config *cfg, int argc, char *argv[])
 233 {
 234         opts_parse_any(cfg, argc, argv, 1);
 235
 236         Fifo *last = cfg->fifos;
 237         cfg->fifos = NULL;
 238         for (Fifo *f = last; f; ) {
 239                 Fifo *next = f->next;
 240                 f->next = cfg->fifos;
 241                 cfg->fifos = f;
 242                 f = next;
 243         }
 244 }
 245
 246 void
 247 read_one(Fifo *f, char *buf)
 248 {
 249         ssize_t current;
 250         ssize_t total;
 251         char *b;
 252         char c;
 253
 254         current = 0;
 255         total = 0;
 256         c = '\0';
 257         b = buf + f->pos;
 258         memset(b, ' ', f->width);
 259         while ((current = read(f->fd, &c, 1)) && c != '\n' && c != '\0' && total++ < f->width)
 260                 *b++ = c;
 261         if (current == -1)
 262                 error("Failed to read: \"%s\". Error: %s\n", f->name, strerror(errno));
 263         /* TODO Record timestamp read */
 264         close(f->fd);
 265         f->fd = -1;
 266 }
 267
 268 void
 269 read_all(Config *cfg, char *buf)
 270 {
 271         fd_set fds;
 272         int maxfd = -1;
 273         int ready;
 274         struct stat st;
 275
 276         FD_ZERO(&fds);
 277         /* TODO: Check TTL */
 278         for (Fifo *f = cfg->fifos; f; f = f->next) {
 279                 /* TODO: Create the FIFO if it doesn't already exist. */
 280                 if (lstat(f->name, &st) < 0)
 281                         fatal("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
 282                 if (!(st.st_mode & S_IFIFO))
 283                         fatal("\"%s\" is not a FIFO\n", f->name);
 284                 debug("opening: %s\n", f->name);
 285                 if (f->fd < 0)
 286                         f->fd = open(f->name, O_RDONLY | O_NONBLOCK);
 287                 if (f->fd == -1)
 288                         /* TODO: Consider backing off retries for failed fifos. */
 289                         fatal("Failed to open \"%s\"\n", f->name);
 290                 if (f->fd > maxfd)
 291                         maxfd = f->fd;
 292                 FD_SET(f->fd, &fds);
 293         }
 294         debug("selecting...\n");
 295         ready = select(maxfd + 1, &fds, NULL, NULL, NULL);
 296         debug("ready: %d\n", ready);
 297         assert(ready != 0);
 298         if (ready < 0)
 299                 fatal("%s", strerror(errno));
 300         for (Fifo *f = cfg->fifos; f; f = f->next) {
 301                 if (FD_ISSET(f->fd, &fds)) {
 302                         debug("reading: %s\n", f->name);
 303                         read_one(f, buf);
 304                 }
 305         }
 306 }
 307
 308 int
 309 main(int argc, char *argv[])
 310 {
 311         int width;
 312         int nfifos = 0;
 313         int seplen;
 314         int prefix = 0;
 315         char *buf;
 316         Config *cfg = &defaults;
 317         Display *display = NULL;
 318
 319         argv0 = argv[0];
 320
 321         opts_parse(cfg, argc, argv);
 322         debug("argv0 = %s\n", argv0);
 323         config_print(cfg);
 324         if (cfg->fifos == NULL)
 325                 usage("No fifo specs were given!\n");
 326
 327         width  = cfg->total_width;
 328         seplen = strlen(cfg->separator);
 329
 330         /* 1st pass to make space for separators */
 331         for (Fifo *f = cfg->fifos; f; f = f->next) {
 332                 f->pos += prefix;
 333                 prefix += seplen;
 334                 nfifos++;
 335         }
 336         width += (seplen * (nfifos - 1));
 337         buf = calloc(1, width + 1);
 338         if (buf == NULL)
 339                 fatal("[memory] Failed to allocate buffer of %d bytes", width);
 340         memset(buf, ' ', width);
 341         buf[width] = '\0';
 342         /* 2nd pass to set the separators */
 343         for (Fifo *f = cfg->fifos; f; f = f->next) {
 344                 if (f->pos) {  /* Skip the first, left-most */
 345                         /* Copying only seplen ensures we omit the '\0' byte. */
 346                         strncpy(buf + (f->pos - seplen), cfg->separator, seplen);
 347                 }
 348         }
 349
 350         if (cfg->output_to_x_root_window && !(display = XOpenDisplay(NULL)))
 351                 fatal("XOpenDisplay failed with: %p\n", display);
 352         /* TODO: nanosleep and nano time diff */
 353         for (;;) {
 354                 /* TODO: Check TTL and maybe blank-out */
 355                 /* TODO: How to trigger TTL check? On select? Alarm signal? */
 356                 /* TODO: Set timeout on read_all based on diff of last time of
 357                  *       read_all and desired time of next TTL check.
 358                  * */
 359                 read_all(cfg, buf);
 360                 if (cfg->output_to_x_root_window) {
 361                         if (XStoreName(display, DefaultRootWindow(display), buf) < 0)
 362                                 fatal("XStoreName failed.\n");
 363                         XFlush(display);
 364                 } else {
 365                         puts(buf);
 366                         fflush(stdout);
 367                 }
 368         }
 369
 370         return EXIT_SUCCESS;
 371 }