BSD 4_2 release

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

#ifndef lint
static char sccsid[] = "@(#)rsh.c       4.8 83/06/10";
#endif

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

#include <netinet/in.h>

#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <pwd.h>
#include <netdb.h>

/*
* rsh - remote shell
*/
/* VARARGS */
int     error();
char    *index(), *rindex(), *malloc(), *getpass(), *sprintf(), *strcpy();

struct  passwd *getpwuid();

int     errno;
int     options;
int     rfd2;
int     sendsig();

#define mask(s) (1 << ((s) - 1))

main(argc, argv0)
       int argc;
       char **argv0;
{
       int rem, pid;
       char *host, *cp, **ap, buf[BUFSIZ], *args, **argv = argv0, *user = 0;
       register int cc;
       int asrsh = 0;
       struct passwd *pwd;
       int readfrom, ready;
       int one = 1;
       struct servent *sp;
       int omask;

       host = rindex(argv[0], '/');
       if (host)
               host++;
       else
               host = argv[0];
       argv++, --argc;
       if (!strcmp(host, "rsh")) {
               host = *argv++, --argc;
               asrsh = 1;
       }
another:
       if (argc > 0 && !strcmp(*argv, "-l")) {
               argv++, argc--;
               if (argc > 0)
                       user = *argv++, argc--;
               goto another;
       }
       if (argc > 0 && !strcmp(*argv, "-n")) {
               argv++, argc--;
               (void) close(0);
               (void) open("/dev/null", 0);
               goto another;
       }
       if (argc > 0 && !strcmp(*argv, "-d")) {
               argv++, argc--;
               options |= SO_DEBUG;
               goto another;
       }
       /*
        * Ignore the -e flag to allow aliases with rlogin
        * to work
        */
       if (argc > 0 && !strncmp(*argv, "-e", 2)) {
               argv++, argc--;
               goto another;
       }
       if (host == 0)
               goto usage;
       if (argv[0] == 0) {
               if (asrsh)
                       *argv0 = "rlogin";
               execv("/usr/ucb/rlogin", argv0);
               perror("/usr/ucb/rlogin");
               exit(1);
       }
       pwd = getpwuid(getuid());
       if (pwd == 0) {
               fprintf(stderr, "who are you?\n");
               exit(1);
       }
       cc = 0;
       for (ap = argv; *ap; ap++)
               cc += strlen(*ap) + 1;
       cp = args = malloc(cc);
       for (ap = argv; *ap; ap++) {
               (void) strcpy(cp, *ap);
               while (*cp)
                       cp++;
               if (ap[1])
                       *cp++ = ' ';
       }
       sp = getservbyname("shell", "tcp");
       if (sp == 0) {
               fprintf(stderr, "rsh: shell/tcp: unknown service\n");
               exit(1);
       }
       rem = rcmd(&host, sp->s_port, pwd->pw_name,
           user ? user : pwd->pw_name, args, &rfd2);
       if (rem < 0)
               exit(1);
       if (rfd2 < 0) {
               fprintf(stderr, "rsh: can't establish stderr\n");
               exit(2);
       }
       if (options & SO_DEBUG) {
               if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
                       perror("setsockopt (stdin)");
               if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
                       perror("setsockopt (stderr)");
       }
       (void) setuid(getuid());
       omask = sigblock(mask(SIGINT)|mask(SIGQUIT)|mask(SIGTERM));
       signal(SIGINT, sendsig);
       signal(SIGQUIT, sendsig);
       signal(SIGTERM, sendsig);
       pid = fork();
       if (pid < 0) {
               perror("fork");
               exit(1);
       }
       ioctl(rfd2, FIONBIO, &one);
       ioctl(rem, FIONBIO, &one);
       if (pid == 0) {
               char *bp; int rembits, wc;
               (void) close(rfd2);
       reread:
               errno = 0;
               cc = read(0, buf, sizeof buf);
               if (cc <= 0)
                       goto done;
               bp = buf;
       rewrite:
               rembits = 1<<rem;
               if (select(16, 0, &rembits, 0, 0) < 0) {
                       if (errno != EINTR) {
                               perror("select");
                               exit(1);
                       }
                       goto rewrite;
               }
               if ((rembits & (1<<rem)) == 0)
                       goto rewrite;
               wc = write(rem, bp, cc);
               if (wc < 0) {
                       if (errno == EWOULDBLOCK)
                               goto rewrite;
                       goto done;
               }
               cc -= wc; bp += wc;
               if (cc == 0)
                       goto reread;
               goto rewrite;
       done:
               (void) shutdown(rem, 1);
               exit(0);
       }
       sigsetmask(omask);
       readfrom = (1<<rfd2) | (1<<rem);
       do {
               ready = readfrom;
               if (select(16, &ready, 0, 0, 0) < 0) {
                       if (errno != EINTR) {
                               perror("select");
                               exit(1);
                       }
                       continue;
               }
               if (ready & (1<<rfd2)) {
                       errno = 0;
                       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;
                       cc = read(rem, buf, sizeof buf);
                       if (cc <= 0) {
                               if (errno != EWOULDBLOCK)
                                       readfrom &= ~(1<<rem);
                       } else
                               (void) write(1, buf, cc);
               }
       } while (readfrom);
       (void) kill(pid, SIGKILL);
       exit(0);
usage:
       fprintf(stderr,
           "usage: rsh host [ -l login ] [ -p passwd ] command\n");
       exit(1);
}

sendsig(signo)
       int signo;
{

       (void) write(rfd2, (char *)&signo, 1);
}