usr/src/usr.bin/rlogin/rlogin.c

#ifndef lint
static char sccsid[] = "@(#)rlogin.c    4.9 83/02/09";
#endif

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

#include <netinet/in.h>

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

/*
 * rlogin - remote login
 */
char    *index(), *rindex(), *malloc(), *getenv();
struct  passwd *getpwuid();
char    *name;
int     rem;
char    cmdchar = '~';
int     eight;
char    *speeds[] =
    { "0", "50", "75", "110", "134", "150", "200", "300",
      "600", "1200", "1800", "2400", "4800", "9600", "19200", "38400" };
char    term[64] = "network";
extern  int errno;
int     lostpeer();

main(argc, argv)
        int argc;
        char **argv;
{
        char *host, *cp;
        struct sgttyb ttyb;
        struct passwd *pwd;
        struct servent *sp;
        int uid, options = 0;

        host = rindex(argv[0], '/');
        if (host)
                host++;
        else
                host = argv[0];
        argv++, --argc;
        if (!strcmp(host, "rlogin"))
                host = *argv++, --argc;
another:
        if (argc > 0 && !strcmp(*argv, "-d")) {
                argv++, argc--;
                options |= SO_DEBUG;
                goto another;
        }
        if (argc > 0 && !strcmp(*argv, "-l")) {
                argv++, argc--;
                if (argc == 0)
                        goto usage;
                name = *argv++; argc--;
                goto another;
        }
        if (argc > 0 && !strncmp(*argv, "-e", 2)) {
                cmdchar = argv[0][2];
                argv++, argc--;
                goto another;
        }
        if (argc > 0 && !strcmp(*argv, "-8")) {
                eight = 1;
                argv++, argc--;
                goto another;
        }
        if (host == 0)
                goto usage;
        if (argc > 0)
                goto usage;
        pwd = getpwuid(getuid());
        if (pwd == 0) {
                fprintf(stderr, "Who are you?\n");
                exit(1);
        }
        sp = getservbyname("login", "tcp");
        if (sp == 0) {
                fprintf(stderr, "rlogin: login/tcp: unknown service\n");
                exit(2);
        }
        cp = getenv("TERM");
        if (cp)
                strcpy(term, cp);
        if (ioctl(0, TIOCGETP, &ttyb)==0) {
                strcat(term, "/");
                strcat(term, speeds[ttyb.sg_ospeed]);
        }
        signal(SIGPIPE, lostpeer);
        rem = rcmd(&host, sp->s_port, pwd->pw_name,
            name ? name : pwd->pw_name, term, 0);
        if (rem < 0)
                exit(1);
        if (options & SO_DEBUG &&
            setsockopt(rem, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
                perror("rlogin: setsockopt (SO_DEBUG)");
        uid = getuid();
        if (setuid(uid) < 0) {
                perror("rlogin: setuid");
                exit(1);
        }
        doit();
        /*NOTREACHED*/
usage:
        fprintf(stderr,
            "usage: rlogin host [ -ex ] [ -l username ]\n");
        exit(1);
}

#define CRLF "\r\n"

int     child;
int     done();

int     defflags;
struct  ttychars deftc;
struct  ttychars notc = {
        -1,     -1,     -1,     -1,     -1,
        -1,     -1,     -1,     -1,     -1,
        -1,     -1,     -1,     -1
};

doit()
{
        int exit();

        ioctl(0, TIOCGET, (char *)&defflags);
        defflags &= ECHO | CRMOD;
        ioctl(0, TIOCCGET, (char *)&deftc);
        notc.tc_startc = deftc.tc_startc;
        notc.tc_stopc = deftc.tc_stopc;
        signal(SIGINT, exit);
        signal(SIGHUP, exit);
        signal(SIGQUIT, exit);
        child = fork();
        if (child == -1) {
                perror("rlogin: fork");
                done();
        }
        signal(SIGINT, SIG_IGN);
        if (child == 0) {
                reader();
                prf("\007Lost connection.");
                exit(3);
        }
        signal(SIGCHLD, done);
        mode(1);
        writer();
        prf("Disconnected.");
        done();
}

done()
{

        mode(0);
        if (child > 0 && kill(child, SIGKILL) >= 0)
                wait((int *)0);
        exit(0);
}

/*
 * writer: write to remote: 0 -> line.
 * ~.   terminate
 * ~^Z  suspend rlogin process.
 * ~^Y  suspend rlogin process, but leave reader alone.
 */
writer()
{
        char b[600], c;
        register char *p;

top:
        p = b;
        while (read(0, &c, 1) > 0) {
                int local;

                if (eight == 0)
                        c &= 0177;
                /*
                 * If we're at the beginning of the line
                 * and recognize a command character, then
                 * we echo locally.  Otherwise, characters
                 * are echo'd remotely.  If the command
                 * character is doubled, this acts as a
                 * force and local echo is suppressed.
                 */
                if (p == b)
                        local = (c == cmdchar);
                if (p == b + 1 && *b == cmdchar)
                        local = (c != cmdchar);
                if (!local) {
                        if (write(rem, &c, 1) == 0) {
                                prf("line gone");
                                return;
                        }
                        if (eight == 0)
                                c &= 0177;
                } else {
                        if (c == 0177)
                                c = deftc.tc_kill;
                        if (c == '\r' || c == '\n') {
                                char cmdc = b[1];

                                if (cmdc == '.' || cmdc == deftc.tc_eofc) {
                                        write(0, CRLF, sizeof(CRLF));
                                        return;
                                }
                                if (cmdc == deftc.tc_suspc ||
                                    cmdc == deftc.tc_dsuspc) {
                                        write(0, CRLF, sizeof(CRLF));
                                        mode(0);
                                        signal(SIGCHLD, SIG_IGN);
                                        kill(cmdc == deftc.tc_suspc ?
                                          0 : getpid(), SIGTSTP);
                                        signal(SIGCHLD, done);
                                        mode(1);
                                        goto top;
                                }
                                *p++ = c;
                                write(rem, b, p - b);
                                goto top;
                        }
                        write(1, &c, 1);
                }
                *p++ = c;
                if (c == deftc.tc_erase) {
                        p -= 2;
                        if (p < b)
                                goto top;
                }
                if (c == deftc.tc_kill || c == 0177 || c == deftc.tc_eofc ||
                    c == '\r' || c == '\n')
                        goto top;
        }
}

oob()
{
        int out = 1+1, atmark;
        char waste[BUFSIZ], mark;

        signal(SIGURG, oob);
        ioctl(1, TIOCFLUSH, (char *)&out);
        for (;;) {
                if (ioctl(rem, SIOCATMARK, &atmark) < 0) {
                        perror("ioctl");
                        break;
                }
                if (atmark)
                        break;
                (void) read(rem, waste, sizeof (waste));
        }
        recv(rem, &mark, 1, SOF_OOB);
        if (mark & TIOCPKT_NOSTOP) {
                notc.tc_stopc = -1;
                notc.tc_startc = -1;
                ioctl(0, TIOCCSET, (char *)&notc);
        }
        if (mark & TIOCPKT_DOSTOP) {
                notc.tc_stopc = deftc.tc_stopc;
                notc.tc_startc = deftc.tc_startc;
                ioctl(0, TIOCCSET, (char *)&notc);
        }
}

/*
 * reader: read from remote: line -> 1
 */
reader()
{
        char rb[BUFSIZ];
        register int cnt;

        signal(SIGURG, oob);
        { int pid = -getpid();
          ioctl(rem, SIOCSPGRP, (char *)&pid); }
        for (;;) {
                cnt = read(rem, rb, sizeof (rb));
                if (cnt <= 0) {
                        if (errno == EINTR)
                                continue;
                        break;
                }
                write(1, rb, cnt);
        }
}

mode(f)
{
        struct ttychars *tc;
        int flags;

        ioctl(0, TIOCGET, (char *)&flags);
        switch (f) {

        case 0:
                flags &= ~CBREAK;
                flags |= defflags;
                tc = &deftc;
                break;

        case 1:
                flags |= CBREAK;
                flags &= ~defflags;
                tc = &notc;
                break;

        default:
                return;
        }
        ioctl(0, TIOCSET, (char *)&flags);
        ioctl(0, TIOCCSET, (char *)tc);
}

/*VARARGS*/
prf(f, a1, a2, a3)
        char *f;
{
        fprintf(stderr, f, a1, a2, a3);
        fprintf(stderr, CRLF);
}

lostpeer()
{
        signal(SIGPIPE, SIG_IGN);
        prf("\007Lost connection");
        done();
}