BSD 4_3_Reno release

[unix-history] / usr / src / usr.bin / rsh / rsh.c

/*-
* Copyright (c) 1983, 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement:  ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. Neither the name of the University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1983, 1990 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)rsh.c       5.21 (Berkeley) 5/15/90";
#endif /* not lint */

/*
* $Source: mit/rsh/RCS/rsh.c,v $
* $Header: mit/rsh/RCS/rsh.c,v 5.1 89/07/31 19:28:59 kfall Exp Locker: kfall $
*/

#include <sys/types.h>
#include <sys/signal.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/file.h>

#include <netinet/in.h>
#include <netdb.h>

#include <pwd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <varargs.h>
#include "pathnames.h"

#ifdef KERBEROS
#include <kerberosIV/des.h>
#include <kerberosIV/krb.h>

CREDENTIALS cred;
Key_schedule schedule;
int use_kerberos = 1, encrypt;
char dst_realm_buf[REALM_SZ], *dest_realm;
extern char *krb_realmofhost();
#endif

/*
* rsh - remote shell
*/
extern int errno;
int rfd2;

main(argc, argv)
       int argc;
       char **argv;
{
       extern char *optarg;
       extern int optind;
       struct passwd *pw;
       struct servent *sp;
       long omask;
       int argoff, asrsh, ch, dflag, nflag, one, pid, rem, uid;
       register char *p;
       char *args, *host, *user, *copyargs();
       void sendsig();

       argoff = asrsh = dflag = nflag = 0;
       one = 1;
       host = user = NULL;

       /* if called as something other than "rsh", use it as the host name */
       if (p = rindex(argv[0], '/'))
               ++p;
       else
               p = argv[0];
       if (strcmp(p, "rsh"))
               host = p;
       else
               asrsh = 1;

       /* handle "rsh host flags" */
       if (!host && argc > 2 && argv[1][0] != '-') {
               host = argv[1];
               argoff = 1;
       }

#ifdef KERBEROS
#define OPTIONS "8KLdek:l:nwx"
#else
#define OPTIONS "8KLdel:nw"
#endif
       while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != EOF)
               switch(ch) {
               case 'K':
#ifdef KERBEROS
                       use_kerberos = 0;
#endif
                       break;
               case 'L':       /* -8Lew are ignored to allow rlogin aliases */
               case 'e':
               case 'w':
               case '8':
                       break;
               case 'd':
                       dflag = 1;
                       break;
               case 'l':
                       user = optarg;
                       break;
#ifdef KERBEROS
               case 'k':
                       dest_realm = dst_realm_buf;
                       strncpy(dest_realm, optarg, REALM_SZ);
                       break;
#endif
               case 'n':
                       nflag = 1;
                       break;
#ifdef KERBEROS
               case 'x':
                       encrypt = 1;
                       des_set_key(cred.session, schedule);
                       break;
#endif
               case '?':
               default:
                       usage();
               }
       optind += argoff;

       /* if haven't gotten a host yet, do so */
       if (!host && !(host = argv[optind++]))
               usage();

       /* if no further arguments, must have been called as rlogin. */
       if (!argv[optind]) {
               if (asrsh)
                       *argv = "rlogin";
               execv(_PATH_RLOGIN, argv);
               (void)fprintf(stderr, "rsh: can't exec %s.\n", _PATH_RLOGIN);
               exit(1);
       }

       argc -= optind;
       argv += optind;

       if (!(pw = getpwuid(uid = getuid()))) {
               (void)fprintf(stderr, "rsh: unknown user id.\n");
               exit(1);
       }
       if (!user)
               user = pw->pw_name;

#ifdef KERBEROS
       /* -x turns off -n */
       if (encrypt)
               nflag = 0;
#endif

       args = copyargs(argv);

       sp = NULL;
#ifdef KERBEROS
       if (use_kerberos) {
               sp = getservbyname((encrypt ? "ekshell" : "kshell"), "tcp");
               if (sp == NULL) {
                       use_kerberos = 0;
                       warning("can't get entry for %s/tcp service",
                           encrypt ? "ekshell" : "kshell");
               }
       }
#endif
       if (sp == NULL)
               sp = getservbyname("shell", "tcp");
       if (sp == NULL) {
               (void)fprintf(stderr, "rsh: shell/tcp: unknown service.\n");
               exit(1);
       }

#ifdef KERBEROS
try_connect:
       if (use_kerberos) {
               rem = KSUCCESS;
               errno = 0;
               if (dest_realm == NULL)
                       dest_realm = krb_realmofhost(host);

               if (encrypt)
                       rem = krcmd_mutual(&host, sp->s_port, user, args,
                           &rfd2, dest_realm, &cred, schedule);
               else
                       rem = krcmd(&host, sp->s_port, user, args, &rfd2,
                           dest_realm);
               if (rem < 0) {
                       use_kerberos = 0;
                       sp = getservbyname("shell", "tcp");
                       if (sp == NULL) {
                               (void)fprintf(stderr,
                                   "rsh: unknown service shell/tcp.\n");
                               exit(1);
                       }
                       if (errno == ECONNREFUSED)
                               warning("remote host doesn't support Kerberos");
                       if (errno == ENOENT)
                               warning("can't provide Kerberos auth data");
                       goto try_connect;
               }
       } else {
               if (encrypt) {
                       (void)fprintf(stderr,
                           "rsh: the -x flag requires Kerberos authentication.\n");
                       exit(1);
               }
               rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
       }
#else
       rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
#endif

       if (rem < 0)
               exit(1);

       if (rfd2 < 0) {
               (void)fprintf(stderr, "rsh: can't establish stderr.\n");
               exit(1);
       }
       if (dflag) {
               if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
                   sizeof(one)) < 0)
                       (void)fprintf(stderr, "rsh: setsockopt: %s.\n",
                           strerror(errno));
               if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
                   sizeof(one)) < 0)
                       (void)fprintf(stderr, "rsh: setsockopt: %s.\n",
                           strerror(errno));
       }

       (void)setuid(uid);
       omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
       if (signal(SIGINT, SIG_IGN) != SIG_IGN)
               (void)signal(SIGINT, sendsig);
       if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
               (void)signal(SIGQUIT, sendsig);
       if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
               (void)signal(SIGTERM, sendsig);

       if (!nflag) {
               pid = fork();
               if (pid < 0) {
                       (void)fprintf(stderr,
                           "rsh: fork: %s.\n", strerror(errno));
                       exit(1);
               }
       }

#ifdef KERBEROS
       if (!encrypt)
#endif
       {
               (void)ioctl(rfd2, FIONBIO, &one);
               (void)ioctl(rem, FIONBIO, &one);
       }

       talk(nflag, omask, pid, rem);

       if (!nflag)
               (void)kill(pid, SIGKILL);
       exit(0);
}

talk(nflag, omask, pid, rem)
       int nflag, pid;
       long omask;
       register int rem;
{
       register int cc, wc;
       register char *bp;
       int readfrom, ready, rembits;
       char buf[BUFSIZ];

       if (!nflag && pid == 0) {
               (void)close(rfd2);

reread:         errno = 0;
               if ((cc = read(0, buf, sizeof buf)) <= 0)
                       goto done;
               bp = buf;

rewrite:        rembits = 1 << rem;
               if (select(16, 0, &rembits, 0, 0) < 0) {
                       if (errno != EINTR) {
                               (void)fprintf(stderr,
                                   "rsh: select: %s.\n", strerror(errno));
                               exit(1);
                       }
                       goto rewrite;
               }
               if ((rembits & (1 << rem)) == 0)
                       goto rewrite;
#ifdef KERBEROS
               if (encrypt)
                       wc = des_write(rem, bp, cc);
               else
#endif
                       wc = write(rem, bp, cc);
               if (wc < 0) {
                       if (errno == EWOULDBLOCK)
                               goto rewrite;
                       goto done;
               }
               bp += wc;
               cc -= wc;
               if (cc == 0)
                       goto reread;
               goto rewrite;
done:
               (void)shutdown(rem, 1);
               exit(0);
       }

       (void)sigsetmask(omask);
       readfrom = (1 << rfd2) | (1 << rem);
       do {
               ready = readfrom;
               if (select(16, &ready, 0, 0, 0) < 0) {
                       if (errno != EINTR) {
                               (void)fprintf(stderr,
                                   "rsh: select: %s.\n", strerror(errno));
                               exit(1);
                       }
                       continue;
               }
               if (ready & (1 << rfd2)) {
                       errno = 0;
#ifdef KERBEROS
                       if (encrypt)
                               cc = des_read(rfd2, buf, sizeof buf);
                       else
#endif
                               cc = read(rfd2, buf, sizeof buf);
                       if (cc <= 0) {
                               if (errno != EWOULDBLOCK)
                                       readfrom &= ~(1 << rfd2);
                       } else
                               (void)write(2, buf, cc);
               }
               if (ready & (1 << rem)) {
                       errno = 0;
#ifdef KERBEROS
                       if (encrypt)
                               cc = des_read(rem, buf, sizeof buf);
                       else
#endif
                               cc = read(rem, buf, sizeof buf);
                       if (cc <= 0) {
                               if (errno != EWOULDBLOCK)
                                       readfrom &= ~(1 << rem);
                       } else
                               (void)write(1, buf, cc);
               }
       } while (readfrom);
}

void
sendsig(signo)
       char signo;
{
#ifdef KERBEROS
       if (encrypt)
               (void)des_write(rfd2, &signo, 1);
       else
#endif
               (void)write(rfd2, &signo, 1);
}

#ifdef KERBEROS
/* VARARGS */
warning(va_alist)
va_dcl
{
       va_list ap;
       char *fmt;

       (void)fprintf(stderr, "rsh: warning, using standard rsh: ");
       va_start(ap);
       fmt = va_arg(ap, char *);
       vfprintf(stderr, fmt, ap);
       va_end(ap);
       (void)fprintf(stderr, ".\n");
}
#endif

char *
copyargs(argv)
       char **argv;
{
       register int cc;
       register char **ap, *p;
       char *args, *malloc();

       cc = 0;
       for (ap = argv; *ap; ++ap)
               cc += strlen(*ap) + 1;
       if (!(args = malloc((u_int)cc))) {
               (void)fprintf(stderr, "rsh: %s.\n", strerror(ENOMEM));
               exit(1);
       }
       for (p = args, ap = argv; *ap; ++ap) {
               (void)strcpy(p, *ap);
               for (p = strcpy(p, *ap); *p; ++p);
               if (ap[1])
                       *p++ = ' ';
       }
       return(args);
}

usage()
{
       (void)fprintf(stderr,
           "usage: rsh [-ndx]%s[-l login] host [command]\n",
#ifdef KERBEROS
           " [-k realm] ");
#else
           " ");
#endif
       exit(1);
}