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