rsh.tproj/rsh.c

   1 /*-
   2  * Copyright (c) 1983, 1990, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 2002 Networks Associates Technology, Inc.
   5  * All rights reserved.
   6  *
   7  * Portions of this software were developed for the FreeBSD Project by
   8  * ThinkSec AS and NAI Labs, the Security Research Division of Network
   9  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
  10  * ("CBOSS"), as part of the DARPA CHATS research program.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  */
  40
  41 #ifndef lint
  42 static const char copyright[] =
  43 "@(#) Copyright (c) 1983, 1990, 1993, 1994\n\
  44         The Regents of the University of California.  All rights reserved.\n";
  45 #endif /* not lint */
  46
  47 #ifndef lint
  48 static const char sccsid[] = "From: @(#)rsh.c   8.3 (Berkeley) 4/6/94";
  49 #endif /* not lint */
  50
  51 #include <sys/cdefs.h>
  52
  53 #include <sys/param.h>
  54 #include <sys/signal.h>
  55 #include <sys/socket.h>
  56 #include <sys/ioctl.h>
  57 #include <sys/file.h>
  58 #include <sys/time.h>
  59
  60 #include <netinet/in.h>
  61 #include <netdb.h>
  62
  63 #include <err.h>
  64 #include <errno.h>
  65 #include <paths.h>
  66 #include <pwd.h>
  67 #include <signal.h>
  68 #include <stdio.h>
  69 #include <stdlib.h>
  70 #include <string.h>
  71 #include <unistd.h>
  72 #include <err.h>
  73
  74 /*
  75  * rsh - remote shell
  76  */
  77 int     rfd2;
  78
  79 int family = PF_UNSPEC;
  80 char rlogin[] = "rlogin";
  81
  82 void    connect_timeout(int);
  83 char   *copyargs(char * const *);
  84 void    sendsig(int);
  85 void    talk(int, long, pid_t, int, int);
  86 void    usage(void);
  87
  88 int
  89 main(int argc, char *argv[])
  90 {
  91         struct passwd const *pw;
  92         struct servent const *sp;
  93         long omask;
  94         int argoff, asrsh, ch, dflag, nflag, one, rem;
  95         pid_t pid = 0;
  96         uid_t uid;
  97         char *args, *host, *p, *user;
  98         int timeout = 0;
  99
 100         argoff = asrsh = dflag = nflag = 0;
 101         one = 1;
 102         host = user = NULL;
 103
 104         /* if called as something other than "rsh", use it as the host name */
 105         if ((p = strrchr(argv[0], '/')))
 106                 ++p;
 107         else
 108                 p = argv[0];
 109         if (strcmp(p, "rsh"))
 110                 host = p;
 111         else
 112                 asrsh = 1;
 113
 114         /* handle "rsh host flags" */
 115         if (!host && argc > 2 && argv[1][0] != '-') {
 116                 host = argv[1];
 117                 argoff = 1;
 118         }
 119
 120 #define OPTIONS "468KLde:l:nt:w"
 121         while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
 122                 switch(ch) {
 123                 case '4':
 124                         family = PF_INET;
 125                         break;
 126
 127                 case '6':
 128                         family = PF_INET6;
 129                         break;
 130
 131                 case 'L':       /* -8Lew are ignored to allow rlogin aliases */
 132                 case 'e':
 133                 case 'w':
 134                 case '8':
 135                         break;
 136                 case 'd':
 137                         dflag = 1;
 138                         break;
 139                 case 'l':
 140                         user = optarg;
 141                         break;
 142                 case 'n':
 143                         nflag = 1;
 144                         break;
 145                 case 't':
 146                         timeout = atoi(optarg);
 147                         break;
 148                 case '?':
 149                 default:
 150                         usage();
 151                 }
 152         optind += argoff;
 153
 154         /* if haven't gotten a host yet, do so */
 155         if (!host && !(host = argv[optind++]))
 156                 usage();
 157
 158         /* if no further arguments, must have been called as rlogin. */
 159         if (!argv[optind]) {
 160                 if (asrsh)
 161                         *argv = rlogin;
 162                 execv(_PATH_RLOGIN, argv);
 163                 err(1, "can't exec %s", _PATH_RLOGIN);
 164         }
 165
 166         argc -= optind;
 167         argv += optind;
 168
 169         if (!(pw = getpwuid(uid = getuid())))
 170                 errx(1, "unknown user id");
 171         if (!user)
 172                 user = pw->pw_name;
 173
 174         args = copyargs(argv);
 175
 176         sp = NULL;
 177         if (sp == NULL)
 178                 sp = getservbyname("shell", "tcp");
 179         if (sp == NULL)
 180                 errx(1, "shell/tcp: unknown service");
 181
 182         if (timeout) {
 183                 signal(SIGALRM, connect_timeout);
 184                 alarm(timeout);
 185         }
 186         rem = rcmd_af(&host, sp->s_port, pw->pw_name, user, args, &rfd2,
 187                       family);
 188         if (timeout) {
 189                 signal(SIGALRM, SIG_DFL);
 190                 alarm(0);
 191         }
 192
 193         if (rem < 0)
 194                 exit(1);
 195
 196         if (rfd2 < 0)
 197                 errx(1, "can't establish stderr");
 198         if (dflag) {
 199                 if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
 200                     sizeof(one)) < 0)
 201                         warn("setsockopt");
 202                 if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
 203                     sizeof(one)) < 0)
 204                         warn("setsockopt");
 205         }
 206
 207         (void)setuid(uid);
 208         omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
 209         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
 210                 (void)signal(SIGINT, sendsig);
 211         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
 212                 (void)signal(SIGQUIT, sendsig);
 213         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
 214                 (void)signal(SIGTERM, sendsig);
 215
 216         if (!nflag) {
 217                 pid = fork();
 218                 if (pid < 0)
 219                         err(1, "fork");
 220         }
 221         else
 222                 (void)shutdown(rem, 1);
 223
 224         (void)ioctl(rfd2, FIONBIO, &one);
 225         (void)ioctl(rem, FIONBIO, &one);
 226
 227         talk(nflag, omask, pid, rem, timeout);
 228
 229         if (!nflag)
 230                 (void)kill(pid, SIGKILL);
 231         exit(0);
 232 }
 233
 234 void
 235 talk(int nflag, long omask, pid_t pid, int rem, int timeout)
 236 {
 237         int cc, wc;
 238         fd_set readfrom, ready, rembits;
 239         char buf[BUFSIZ];
 240         const char *bp;
 241         struct timeval tvtimeout;
 242         int nfds, srval;
 243
 244         if (!nflag && pid == 0) {
 245                 (void)close(rfd2);
 246
 247 reread:         errno = 0;
 248                 if ((cc = read(0, buf, sizeof buf)) <= 0)
 249                         goto done;
 250                 bp = buf;
 251
 252 rewrite:
 253                 if (rem >= FD_SETSIZE)
 254                         errx(1, "descriptor too big");
 255                 FD_ZERO(&rembits);
 256                 FD_SET(rem, &rembits);
 257                 nfds = rem + 1;
 258                 if (select(nfds, 0, &rembits, 0, 0) < 0) {
 259                         if (errno != EINTR)
 260                                 err(1, "select");
 261                         goto rewrite;
 262                 }
 263                 if (!FD_ISSET(rem, &rembits))
 264                         goto rewrite;
 265                 wc = write(rem, bp, cc);
 266                 if (wc < 0) {
 267                         if (errno == EWOULDBLOCK)
 268                                 goto rewrite;
 269                         goto done;
 270                 }
 271                 bp += wc;
 272                 cc -= wc;
 273                 if (cc == 0)
 274                         goto reread;
 275                 goto rewrite;
 276 done:
 277                 (void)shutdown(rem, 1);
 278                 exit(0);
 279         }
 280
 281         tvtimeout.tv_sec = timeout;
 282         tvtimeout.tv_usec = 0;
 283
 284         (void)sigsetmask(omask);
 285         if (rfd2 >= FD_SETSIZE || rem >= FD_SETSIZE)
 286                 errx(1, "descriptor too big");
 287         FD_ZERO(&readfrom);
 288         FD_SET(rfd2, &readfrom);
 289         FD_SET(rem, &readfrom);
 290         nfds = MAX(rfd2+1, rem+1);
 291         do {
 292                 ready = readfrom;
 293                 if (timeout) {
 294                         srval = select(nfds, &ready, 0, 0, &tvtimeout);
 295                 } else {
 296                         srval = select(nfds, &ready, 0, 0, 0);
 297                 }
 298
 299                 if (srval < 0) {
 300                         if (errno != EINTR)
 301                                 err(1, "select");
 302                         continue;
 303                 }
 304                 if (srval == 0)
 305                         errx(1, "timeout reached (%d seconds)\n", timeout);
 306                 if (FD_ISSET(rfd2, &ready)) {
 307                         errno = 0;
 308                         cc = read(rfd2, buf, sizeof buf);
 309                         if (cc <= 0) {
 310                                 if (errno != EWOULDBLOCK)
 311                                         FD_CLR(rfd2, &readfrom);
 312                         } else
 313                                 (void)write(STDERR_FILENO, buf, cc);
 314                 }
 315                 if (FD_ISSET(rem, &ready)) {
 316                         errno = 0;
 317                         cc = read(rem, buf, sizeof buf);
 318                         if (cc <= 0) {
 319                                 if (errno != EWOULDBLOCK)
 320                                         FD_CLR(rem, &readfrom);
 321                         } else
 322                                 (void)write(STDOUT_FILENO, buf, cc);
 323                 }
 324         } while (FD_ISSET(rfd2, &readfrom) || FD_ISSET(rem, &readfrom));
 325 }
 326
 327 void
 328 connect_timeout(int sig)
 329 {
 330         char message[] = "timeout reached before connection completed.\n";
 331
 332         write(STDERR_FILENO, message, sizeof(message) - 1);
 333         _exit(1);
 334 }
 335
 336 void
 337 sendsig(int sig)
 338 {
 339         char signo;
 340
 341         signo = sig;
 342         (void)write(rfd2, &signo, 1);
 343 }
 344
 345 char *
 346 copyargs(char * const *argv)
 347 {
 348         int cc;
 349         char *args, *p;
 350         char * const *ap;
 351
 352         cc = 0;
 353         for (ap = argv; *ap; ++ap)
 354                 cc += strlen(*ap) + 1;
 355         if (!(args = malloc((u_int)cc)))
 356                 err(1, NULL);
 357         for (p = args, ap = argv; *ap; ++ap) {
 358                 (void)strcpy(p, *ap);
 359                 for (p = strcpy(p, *ap); *p; ++p);
 360                 if (ap[1])
 361                         *p++ = ' ';
 362         }
 363         return (args);
 364 }
 365
 366 void
 367 usage(void)
 368 {
 369
 370         (void)fprintf(stderr,
 371             "usage: rsh [-46] [-nd] [-l login] [-t timeout] host [command]\n");
 372         exit(1);
 373 }