158 lines
3.7 KiB
C
158 lines
3.7 KiB
C
/*
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* TNET A server program for MINIX which implements the TCP/IP
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* suite of networking protocols. It is based on the
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* TCP/IP code written by Phil Karn et al, as found in
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* his NET package for Packet Radio communications.
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*
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* This file contains an implementation of the "server"
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* for the TELNET protocol. This protocol can be used to
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* remote-login on other systems, just like a normal TTY
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* session.
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*
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* Usage: telnetd [-dv]
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*
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* Version: @(#)telnetd.c 1.00 07/26/92
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*
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* Author: Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
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* Michael Temari, <temari@temari.ae.ge.com>
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*/
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#include <sys/types.h>
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#include <fcntl.h>
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#include <sys/wait.h>
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <time.h>
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#include <stdio.h>
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#include <ttyent.h>
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#include <utmp.h>
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#include <net/gen/in.h>
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#include <net/gen/tcp.h>
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#include <net/gen/tcp_io.h>
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#include <net/gen/socket.h>
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#include <net/gen/netdb.h>
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#include <net/gen/inet.h>
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#include "telnetd.h"
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static char *Version = "@(#) telnetd 1.00 (07/26/92)";
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int opt_d = 0; /* debugging output flag */
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_PROTOTYPE(void usage, (void));
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_PROTOTYPE(int main, (int argc, char *argv[]));
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_PROTOTYPE(void wtmp, (int type, int linenr, char *line, pid_t pid,
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char *host));
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void usage()
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{
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fprintf(stderr, "Usage: telnetd [-dv]\n");
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exit(-1);
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}
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int main(argc, argv)
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int argc;
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char *argv[];
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{
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char buff[128];
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register int c;
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int pty_fd;
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int tty_fd;
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pid_t pid;
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int lineno;
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char *tty_name;
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struct ttyent *ttyp;
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nwio_tcpconf_t tcpconf;
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struct hostent *hostent;
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char *hostname;
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opterr = 0;
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while ((c = getopt(argc, argv, "dv")) != EOF) switch(c) {
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case 'd':
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case 'v':
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opt_d = 1;
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break;
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default:
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usage();
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}
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/* No more arguments allowed. */
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if (optind != argc) usage();
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/* Obtain the name of the remote host. */
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if (ioctl(0, NWIOGTCPCONF, &tcpconf) < 0) {
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sprintf(buff, "Unable to obtain your IP address\r\n");
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(void) write(1, buff, strlen(buff));
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return(-1);
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}
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if ((hostent = gethostbyaddr((char *) &tcpconf.nwtc_remaddr,
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sizeof(tcpconf.nwtc_remaddr), AF_INET)) != NULL) {
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hostname = hostent->h_name;
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} else {
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hostname = inet_ntoa(tcpconf.nwtc_remaddr);
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}
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/* Try allocating a PTY. */
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if (get_pty(&pty_fd, &tty_name) < 0) {
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sprintf(buff, "I am sorry, but there is no free PTY left!\r\n");
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(void) write(1, buff, strlen(buff));
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return(-1);
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}
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/* Find the tty in the tty table. */
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lineno = 0;
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for (;;) {
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if ((ttyp = getttyent()) == NULL) {
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sprintf(buff, "Can't find %s in the tty table\r\n");
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(void) write(1, buff, strlen(buff));
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}
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if (strcmp(ttyp->ty_name, tty_name+5) == 0) break;
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lineno++;
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}
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endttyent();
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/* Initialize the connection to an 8 bit clean channel. */
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term_init();
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/* Fork off a child process and have it execute a getty(8). */
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if ((pid = fork()) == 0) {
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/* Set up a new session. */
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setsid();
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if ((tty_fd = open(tty_name, O_RDWR)) < 0) {
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sprintf(buff, "Can't open %s\r\n", tty_name);
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(void) write(1, buff, strlen(buff));
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return(-1);
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}
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close(pty_fd);
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dup2(tty_fd, 0);
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dup2(tty_fd, 1);
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dup2(tty_fd, 2);
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close(tty_fd);
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(void) execl("/usr/sbin/getty", "getty", (char *)NULL);
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(void) execl("/usr/bin/getty", "getty", (char *)NULL);
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(void) execl("/usr/bin/login", "login", (char *)NULL);
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(void) write(1, "EXEC failed!\r\n", 14);
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} else if (pid < 0) {
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sprintf(buff, "I am sorry, but the fork(2) call failed!\r\n");
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(void) write(1, buff, strlen(buff));
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(void) close(pty_fd);
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return(-1);
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}
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wtmp(LOGIN_PROCESS, lineno, tty_name+5, pid, hostname);
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term_inout(pty_fd);
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(void) close(pty_fd);
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wtmp(DEAD_PROCESS, lineno, tty_name+5, pid, hostname);
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chown(tty_name, 0, 0);
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chmod(tty_name, 0666);
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return(0);
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}
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