usr.sbin/watch/watch.c

   1 /*
   2  * Copyright (c) 1995 Ugen J.S.Antsilevich
   3  *
   4  * Redistribution and use in source forms, with and without modification,
   5  * are permitted provided that this entire comment appears intact.
   6  *
   7  * Redistribution in binary form may occur without any restrictions.
   8  * Obviously, it would be nice if you gave credit where credit is due
   9  * but requiring it would be too onerous.
  10  *
  11  * This software is provided ``AS IS'' without any warranties of any kind.
  12  *
  13  * Snoop stuff.
  14  */
  15
  16 #include <sys/cdefs.h>
  17 __FBSDID("$FreeBSD$");
  18
  19 #include <sys/param.h>
  20 #include <sys/fcntl.h>
  21 #include <sys/filio.h>
  22 #include <sys/snoop.h>
  23 #include <sys/stat.h>
  24 #include <sys/linker.h>
  25 #include <sys/module.h>
  26
  27 #include <err.h>
  28 #include <errno.h>
  29 #include <locale.h>
  30 #include <paths.h>
  31 #include <signal.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <sysexits.h>
  36 #include <termcap.h>
  37 #include <termios.h>
  38 #include <time.h>
  39 #include <unistd.h>
  40
  41 #define MSG_INIT        "Snoop started."
  42 #define MSG_OFLOW       "Snoop stopped due to overflow. Reconnecting."
  43 #define MSG_CLOSED      "Snoop stopped due to tty close. Reconnecting."
  44 #define MSG_CHANGE      "Snoop device change by user request."
  45 #define MSG_NOWRITE     "Snoop device change due to write failure."
  46
  47
  48 #define DEV_NAME_LEN    1024    /* for /dev/ttyXX++ */
  49 #define MIN_SIZE        256
  50
  51 #define CHR_SWITCH      24      /* Ctrl+X        */
  52 #define CHR_CLEAR       23      /* Ctrl+V        */
  53
  54 static void     clear(void);
  55 static void     timestamp(const char *);
  56 static void     set_tty(void);
  57 static void     unset_tty(void);
  58 static void     fatal(int, const char *);
  59 static int      open_snp(void);
  60 static void     cleanup(int);
  61 static void     usage(void) __dead2;
  62 static void     setup_scr(void);
  63 static void     attach_snp(void);
  64 static void     detach_snp(void);
  65 static void     set_dev(const char *);
  66 static void     ask_dev(char *, const char *);
  67
  68 int             opt_reconn_close = 0;
  69 int             opt_reconn_oflow = 0;
  70 int             opt_interactive = 1;
  71 int             opt_timestamp = 0;
  72 int             opt_write = 0;
  73 int             opt_no_switch = 0;
  74 const char      *opt_snpdev;
  75
  76 char            dev_name[DEV_NAME_LEN];
  77 int             snp_io;
  78 int             std_in = 0, std_out = 1;
  79
  80
  81 int             clear_ok = 0;
  82 struct termios  otty;
  83 char            tbuf[1024], gbuf[1024];
  84
  85
  86 static void
  87 clear(void)
  88 {
  89         if (clear_ok)
  90                 tputs(gbuf, 1, putchar);
  91         fflush(stdout);
  92 }
  93
  94 static void
  95 timestamp(const char *buf)
  96 {
  97         time_t          t;
  98         char            btmp[1024];
  99         clear();
 100         printf("\n---------------------------------------------\n");
 101         t = time(NULL);
 102         strftime(btmp, 1024, "Time: %d %b %H:%M", localtime(&t));
 103         printf("%s\n", btmp);
 104         printf("%s\n", buf);
 105         printf("---------------------------------------------\n");
 106         fflush(stdout);
 107 }
 108
 109 static void
 110 set_tty(void)
 111 {
 112         struct termios  ntty;
 113
 114         tcgetattr (std_in, &otty);
 115         ntty = otty;
 116         ntty.c_lflag &= ~ICANON;    /* disable canonical operation  */
 117         ntty.c_lflag &= ~ECHO;
 118 #ifdef FLUSHO
 119         ntty.c_lflag &= ~FLUSHO;
 120 #endif
 121 #ifdef PENDIN
 122         ntty.c_lflag &= ~PENDIN;
 123 #endif
 124 #ifdef IEXTEN
 125         ntty.c_lflag &= ~IEXTEN;
 126 #endif
 127         ntty.c_cc[VMIN] = 1;        /* minimum of one character */
 128         ntty.c_cc[VTIME] = 0;       /* timeout value        */
 129
 130         ntty.c_cc[VINTR] = 07;   /* ^G */
 131         ntty.c_cc[VQUIT] = 07;   /* ^G */
 132         tcsetattr (std_in, TCSANOW, &ntty);
 133 }
 134
 135 static void
 136 unset_tty(void)
 137 {
 138         tcsetattr (std_in, TCSANOW, &otty);
 139 }
 140
 141
 142 static void
 143 fatal(int error, const char *buf)
 144 {
 145         unset_tty();
 146         if (buf)
 147                 errx(error, "fatal: %s", buf);
 148         else
 149                 exit(error);
 150 }
 151
 152 static int
 153 open_snp(void)
 154 {
 155         char            snp[] = {_PATH_DEV "snpXXX"};
 156         int             f, mode, pos, c;
 157
 158         pos = strlen(snp) - 3;
 159         if (opt_write)
 160                 mode = O_RDWR;
 161         else
 162                 mode = O_RDONLY;
 163
 164         if (opt_snpdev == NULL)
 165                 for (c = 0; c <= 999; c++) {
 166                         snprintf(snp+pos, 4, "%d", c);
 167                         if ((f = open(snp, mode)) < 0) {
 168                                 if (errno == EBUSY)
 169                                         continue;
 170                                 err(1, "open %s", snp);
 171                         }
 172                         return f;
 173                 }
 174         else
 175                 if ((f = open(opt_snpdev, mode)) != -1)
 176                         return (f);
 177         fatal(EX_OSFILE, "cannot open snoop device");
 178         return (0);
 179 }
 180
 181
 182 static void
 183 cleanup(int signo __unused)
 184 {
 185         if (opt_timestamp)
 186                 timestamp("Logging Exited.");
 187         close(snp_io);
 188         unset_tty();
 189         exit(EX_OK);
 190 }
 191
 192
 193 static void
 194 usage(void)
 195 {
 196         fprintf(stderr, "usage: watch [-ciotnW] [tty name]\n");
 197         exit(EX_USAGE);
 198 }
 199
 200 static void
 201 setup_scr(void)
 202 {
 203         char           *cbuf = gbuf, *term;
 204         if (!opt_interactive)
 205                 return;
 206         if ((term = getenv("TERM")))
 207                 if (tgetent(tbuf, term) == 1)
 208                         if (tgetstr("cl", &cbuf))
 209                                 clear_ok = 1;
 210         set_tty();
 211         clear();
 212 }
 213
 214 static void
 215 detach_snp(void)
 216 {
 217         int             fd;
 218
 219         fd = -1;
 220         ioctl(snp_io, SNPSTTY, &fd);
 221 }
 222
 223 static void
 224 attach_snp(void)
 225 {
 226         int             snp_tty;
 227
 228         snp_tty = open(dev_name, O_RDONLY | O_NONBLOCK);
 229         if (snp_tty < 0)
 230                 fatal(EX_DATAERR, "can't open device");
 231         if (ioctl(snp_io, SNPSTTY, &snp_tty) != 0)
 232                 fatal(EX_UNAVAILABLE, "cannot attach to tty");
 233         close(snp_tty);
 234         if (opt_timestamp)
 235                 timestamp("Logging Started.");
 236 }
 237
 238
 239 static void
 240 set_dev(const char *name)
 241 {
 242         char            buf[DEV_NAME_LEN];
 243         struct stat     sb;
 244
 245         if (strlen(name) > 5 && !strncmp(name, _PATH_DEV, sizeof _PATH_DEV - 1)) {
 246                 snprintf(buf, sizeof buf, "%s", name);
 247         } else {
 248                 if (strlen(name) == 2)
 249                         sprintf(buf, "%s%s", _PATH_TTY, name);
 250                 else
 251                         sprintf(buf, "%s%s", _PATH_DEV, name);
 252         }
 253
 254         if (*name == '\0' || stat(buf, &sb) < 0)
 255                 fatal(EX_DATAERR, "bad device name");
 256
 257         if ((sb.st_mode & S_IFMT) != S_IFCHR)
 258                 fatal(EX_DATAERR, "must be a character device");
 259
 260         strncpy(dev_name, buf, DEV_NAME_LEN);
 261
 262         attach_snp();
 263 }
 264
 265 void
 266 ask_dev(char *dbuf, const char *msg)
 267 {
 268         char            buf[DEV_NAME_LEN];
 269         int             len;
 270
 271         clear();
 272         unset_tty();
 273
 274         if (msg)
 275                 printf("%s\n", msg);
 276         if (dbuf)
 277                 printf("Enter device name [%s]:", dbuf);
 278         else
 279                 printf("Enter device name:");
 280
 281         if (fgets(buf, DEV_NAME_LEN - 1, stdin)) {
 282                 len = strlen(buf);
 283                 if (buf[len - 1] == '\n')
 284                         buf[len - 1] = '\0';
 285                 if (buf[0] != '\0' && buf[0] != ' ')
 286                         strcpy(dbuf, buf);
 287         }
 288         set_tty();
 289 }
 290
 291 #define READB_LEN       5
 292
 293 int
 294 main(int ac, char *av[])
 295 {
 296         int             ch, res, rv, nread;
 297         size_t          b_size = MIN_SIZE;
 298         char            *buf, chb[READB_LEN];
 299         fd_set          fd_s;
 300
 301         (void) setlocale(LC_TIME, "");
 302
 303         if (isatty(std_out))
 304                 opt_interactive = 1;
 305         else
 306                 opt_interactive = 0;
 307
 308
 309         while ((ch = getopt(ac, av, "Wciotnf:")) != -1)
 310                 switch (ch) {
 311                 case 'W':
 312                         opt_write = 1;
 313                         break;
 314                 case 'c':
 315                         opt_reconn_close = 1;
 316                         break;
 317                 case 'i':
 318                         opt_interactive = 1;
 319                         break;
 320                 case 'o':
 321                         opt_reconn_oflow = 1;
 322                         break;
 323                 case 't':
 324                         opt_timestamp = 1;
 325                         break;
 326                 case 'n':
 327                         opt_no_switch = 1;
 328                         break;
 329                 case 'f':
 330                         opt_snpdev = optarg;
 331                         break;
 332                 case '?':
 333                 default:
 334                         usage();
 335                 }
 336
 337         if (modfind("snp") == -1)
 338                 if (kldload("snp") == -1 || modfind("snp") == -1)
 339                         warn("snp module not available");
 340
 341         signal(SIGINT, cleanup);
 342
 343         snp_io = open_snp();
 344         setup_scr();
 345
 346         if (*(av += optind) == NULL) {
 347                 if (opt_interactive && !opt_no_switch)
 348                         ask_dev(dev_name, MSG_INIT);
 349                 else
 350                         fatal(EX_DATAERR, "no device name given");
 351         } else
 352                 strncpy(dev_name, *av, DEV_NAME_LEN);
 353
 354         set_dev(dev_name);
 355
 356         if (!(buf = (char *) malloc(b_size)))
 357                 fatal(EX_UNAVAILABLE, "malloc failed");
 358
 359         FD_ZERO(&fd_s);
 360
 361         while (1) {
 362                 if (opt_interactive)
 363                         FD_SET(std_in, &fd_s);
 364                 FD_SET(snp_io, &fd_s);
 365                 res = select(snp_io + 1, &fd_s, NULL, NULL, NULL);
 366                 if (opt_interactive && FD_ISSET(std_in, &fd_s)) {
 367
 368                         if ((res = ioctl(std_in, FIONREAD, &nread)) != 0)
 369                                 fatal(EX_OSERR, "ioctl(FIONREAD)");
 370                         if (nread > READB_LEN)
 371                                 nread = READB_LEN;
 372                         rv = read(std_in, chb, nread);
 373                         if (rv == -1 || rv != nread)
 374                                 fatal(EX_IOERR, "read (stdin) failed");
 375
 376                         switch (chb[0]) {
 377                         case CHR_CLEAR:
 378                                 clear();
 379                                 break;
 380                         case CHR_SWITCH:
 381                                 if (!opt_no_switch) {
 382                                         detach_snp();
 383                                         ask_dev(dev_name, MSG_CHANGE);
 384                                         set_dev(dev_name);
 385                                         break;
 386                                 }
 387                         default:
 388                                 if (opt_write) {
 389                                         rv = write(snp_io, chb, nread);
 390                                         if (rv == -1 || rv != nread) {
 391                                                 detach_snp();
 392                                                 if (opt_no_switch)
 393                                                         fatal(EX_IOERR,
 394                                                           "write failed");
 395                                                 ask_dev(dev_name, MSG_NOWRITE);
 396                                                 set_dev(dev_name);
 397                                         }
 398                                 }
 399
 400                         }
 401                 }
 402                 if (!FD_ISSET(snp_io, &fd_s))
 403                         continue;
 404
 405                 if ((res = ioctl(snp_io, FIONREAD, &nread)) != 0)
 406                         fatal(EX_OSERR, "ioctl(FIONREAD)");
 407
 408                 switch (nread) {
 409                 case SNP_OFLOW:
 410                         if (opt_reconn_oflow)
 411                                 attach_snp();
 412                         else if (opt_interactive && !opt_no_switch) {
 413                                 ask_dev(dev_name, MSG_OFLOW);
 414                                 set_dev(dev_name);
 415                         } else
 416                                 cleanup(-1);
 417                         break;
 418                 case SNP_DETACH:
 419                 case SNP_TTYCLOSE:
 420                         if (opt_reconn_close)
 421                                 attach_snp();
 422                         else if (opt_interactive && !opt_no_switch) {
 423                                 ask_dev(dev_name, MSG_CLOSED);
 424                                 set_dev(dev_name);
 425                         } else
 426                                 cleanup(-1);
 427                         break;
 428                 default:
 429                         if (nread < (b_size / 2) && (b_size / 2) > MIN_SIZE) {
 430                                 free(buf);
 431                                 if (!(buf = (char *) malloc(b_size / 2)))
 432                                         fatal(EX_UNAVAILABLE, "malloc failed");
 433                                 b_size = b_size / 2;
 434                         }
 435                         if (nread > b_size) {
 436                                 b_size = (nread % 2) ? (nread + 1) : (nread);
 437                                 free(buf);
 438                                 if (!(buf = (char *) malloc(b_size)))
 439                                         fatal(EX_UNAVAILABLE, "malloc failed");
 440                         }
 441                         rv = read(snp_io, buf, nread);
 442                         if (rv == -1 || rv != nread)
 443                                 fatal(EX_IOERR, "read failed");
 444                         rv = write(std_out, buf, nread);
 445                         if (rv == -1 || rv != nread)
 446                                 fatal(EX_IOERR, "write failed");
 447                 }
 448         }                       /* While */
 449         return(0);
 450 }
 451