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  * $FreeBSD: src/usr.sbin/watch/watch.c,v 1.18.2.3 2002/08/17 00:59:03 mikeh Exp $
  16  * $DragonFly: src/usr.sbin/watch/watch.c,v 1.5 2005/12/05 01:23:23 swildner Exp $
  17  */
  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 <locale.h>
  29 #include <paths.h>
  30 #include <signal.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <sysexits.h>
  35 #include <termcap.h>
  36 #include <termios.h>
  37 #include <time.h>
  38 #include <unistd.h>
  39
  40 #define MSG_INIT        "Snoop started."
  41 #define MSG_OFLOW       "Snoop stopped due to overflow. Reconnecting."
  42 #define MSG_CLOSED      "Snoop stopped due to tty close. Reconnecting."
  43 #define MSG_CHANGE      "Snoop device change by user request."
  44 #define MSG_NOWRITE     "Snoop device change due to write failure."
  45
  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);
  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 dev_t           snp_tty;
  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 "snpX"};
 156         char            c;
 157         int             f, mode;
 158
 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 <= '9'; c++) {
 166                         snp[8] = c;
 167                         if ((f = open(snp, mode)) < 0)
 168                                 continue;
 169                         return f;
 170                 }
 171         else
 172                 if ((f = open(opt_snpdev, mode)) != -1)
 173                         return (f);
 174         fatal(EX_OSFILE, "cannot open snoop device");
 175         return (0);
 176 }
 177
 178
 179 static void
 180 cleanup(int signo __unused)
 181 {
 182         if (opt_timestamp)
 183                 timestamp("Logging Exited.");
 184         close(snp_io);
 185         unset_tty();
 186         exit(EX_OK);
 187 }
 188
 189
 190 static void
 191 usage(void)
 192 {
 193         fprintf(stderr, "usage: watch [-ciotnW] [tty name]\n");
 194         exit(EX_USAGE);
 195 }
 196
 197 static void
 198 setup_scr(void)
 199 {
 200         char           *cbuf = gbuf, *term;
 201         if (!opt_interactive)
 202                 return;
 203         if ((term = getenv("TERM")))
 204                 if (tgetent(tbuf, term) == 1)
 205                         if (tgetstr("cl", &cbuf))
 206                                 clear_ok = 1;
 207         set_tty();
 208         clear();
 209 }
 210
 211 static void
 212 detach_snp(void)
 213 {
 214         dev_t           dev;
 215
 216         dev = NODEV;
 217         ioctl(snp_io, SNPSTTY, &dev);
 218 }
 219
 220 static void
 221 attach_snp(void)
 222 {
 223         if (ioctl(snp_io, SNPSTTY, &snp_tty) != 0)
 224                 fatal(EX_UNAVAILABLE, "cannot attach to tty");
 225         if (opt_timestamp)
 226                 timestamp("Logging Started.");
 227 }
 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         }
 239         else {
 240                 if (strlen(name) == 2)
 241                         sprintf(buf, "%s%s", _PATH_TTY, name);
 242                 else
 243                         sprintf(buf, "%s%s", _PATH_DEV, name);
 244         }
 245
 246         if (*name == '\0' || stat(buf, &sb) < 0)
 247                 fatal(EX_DATAERR, "bad device name");
 248
 249         if ((sb.st_mode & S_IFMT) != S_IFCHR)
 250                 fatal(EX_DATAERR, "must be a character device");
 251
 252         snp_tty = sb.st_rdev;
 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             res, idata, rv;
 288         size_t          nread, b_size = MIN_SIZE;
 289         char            ch, *buf, chb[READB_LEN];
 290         fd_set          fd_s;
 291
 292         setlocale(LC_TIME, "");
 293
 294         if (isatty(std_out))
 295                 opt_interactive = 1;
 296         else
 297                 opt_interactive = 0;
 298
 299
 300         while ((ch = getopt(ac, av, "Wciotnf:")) != -1)
 301                 switch (ch) {
 302                 case 'W':
 303                         opt_write = 1;
 304                         break;
 305                 case 'c':
 306                         opt_reconn_close = 1;
 307                         break;
 308                 case 'i':
 309                         opt_interactive = 1;
 310                         break;
 311                 case 'o':
 312                         opt_reconn_oflow = 1;
 313                         break;
 314                 case 't':
 315                         opt_timestamp = 1;
 316                         break;
 317                 case 'n':
 318                         opt_no_switch = 1;
 319                         break;
 320                 case 'f':
 321                         opt_snpdev = optarg;
 322                         break;
 323                 case '?':
 324                 default:
 325                         usage();
 326                 }
 327
 328         if (modfind("snp") == -1)
 329                 if (kldload("snp") == -1 || modfind("snp") == -1)
 330                         warn("snp module not available");
 331
 332         signal(SIGINT, cleanup);
 333
 334         setup_scr();
 335         snp_io = open_snp();
 336
 337         if (*(av += optind) == NULL) {
 338                 if (opt_interactive && !opt_no_switch)
 339                         ask_dev(dev_name, MSG_INIT);
 340                 else
 341                         fatal(EX_DATAERR, "no device name given");
 342         } else
 343                 strncpy(dev_name, *av, DEV_NAME_LEN);
 344
 345         set_dev(dev_name);
 346
 347         if (!(buf = (char *) malloc(b_size)))
 348                 fatal(EX_UNAVAILABLE, "malloc failed");
 349
 350         FD_ZERO(&fd_s);
 351
 352         while (1) {
 353                 if (opt_interactive)
 354                         FD_SET(std_in, &fd_s);
 355                 FD_SET(snp_io, &fd_s);
 356                 res = select(snp_io + 1, &fd_s, NULL, NULL, NULL);
 357                 if (opt_interactive && FD_ISSET(std_in, &fd_s)) {
 358
 359                         if ((res = ioctl(std_in, FIONREAD, &nread)) != 0)
 360                                 fatal(EX_OSERR, "ioctl(FIONREAD)");
 361                         if (nread > READB_LEN)
 362                                 nread = READB_LEN;
 363                         rv = read(std_in, chb, nread);
 364                         if (rv == -1 || (unsigned)rv != nread)
 365                                 fatal(EX_IOERR, "read (stdin) failed");
 366
 367                         switch (chb[0]) {
 368                         case CHR_CLEAR:
 369                                 clear();
 370                                 break;
 371                         case CHR_SWITCH:
 372                                 if (!opt_no_switch) {
 373                                         detach_snp();
 374                                         ask_dev(dev_name, MSG_CHANGE);
 375                                         set_dev(dev_name);
 376                                         break;
 377                                 }
 378                         default:
 379                                 if (opt_write) {
 380                                         rv = write(snp_io, chb, nread);
 381                                         if (rv == -1 || (unsigned)rv != nread) {
 382                                                 detach_snp();
 383                                                 if (opt_no_switch)
 384                                                         fatal(EX_IOERR, "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, &idata)) != 0)
 396                         fatal(EX_OSERR, "ioctl(FIONREAD)");
 397
 398                 switch (idata) {
 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                         nread = (unsigned)idata;
 420                         if (nread < (b_size / 2) && (b_size / 2) > MIN_SIZE) {
 421                                 free(buf);
 422                                 if (!(buf = (char *) malloc(b_size / 2)))
 423                                         fatal(EX_UNAVAILABLE, "malloc failed");
 424                                 b_size = b_size / 2;
 425                         }
 426                         if (nread > b_size) {
 427                                 b_size = (nread % 2) ? (nread + 1) : (nread);
 428                                 free(buf);
 429                                 if (!(buf = (char *) malloc(b_size)))
 430                                         fatal(EX_UNAVAILABLE, "malloc failed");
 431                         }
 432                         rv = read(snp_io, buf, nread);
 433                         if (rv == -1 || (unsigned)rv != nread)
 434                                 fatal(EX_IOERR, "read failed");
 435                         rv = write(std_out, buf, nread);
 436                         if (rv == -1 || (unsigned)rv != nread)
 437                                 fatal(EX_IOERR, "write failed");
 438                 }
 439         }                       /* While */
 440         return(0);
 441 }
 442