113 lines
2.9 KiB
C
113 lines
2.9 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 <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 <utmp.h>
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#include <time.h>
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#include <stdio.h>
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#include "telnetd.h"
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static char PATH_UTMP[] = "/etc/utmp";
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static char PATH_WTMP[] = "/usr/adm/wtmp";
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void wtmp(int type, int linenr, char *line, pid_t pid, char *host);
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void report(char *label);
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void wtmp(type, linenr, line, pid, host)
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int type; /* type of entry */
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int linenr; /* line number in ttytab */
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char *line; /* tty name (only good on login) */
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pid_t pid; /* pid of process */
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char *host; /* name of the remote host */
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{
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/* Log an event into the UTMP and WTMP files. */
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struct utmp utmp; /* UTMP/WTMP User Accounting */
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int fd;
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/* Clear the utmp record. */
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memset((void *) &utmp, 0, sizeof(utmp));
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/* Fill in utmp. */
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switch (type) {
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case LOGIN_PROCESS:
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/* A new login, fill in line and host name. */
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strncpy(utmp.ut_line, line, sizeof(utmp.ut_line));
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strncpy(utmp.ut_host, host, sizeof(utmp.ut_host));
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break;
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case DEAD_PROCESS:
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/* A logout. Use the current utmp entry, but make sure it is a
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* user process exiting, and not getty or login giving up.
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*/
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if ((fd = open(PATH_UTMP, O_RDONLY)) < 0) {
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if (errno != ENOENT) report(PATH_UTMP);
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return;
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}
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if (lseek(fd, (off_t) (linenr+1) * sizeof(utmp), SEEK_SET) == -1
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|| read(fd, &utmp, sizeof(utmp)) == -1
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) {
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report(PATH_UTMP);
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close(fd);
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return;
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}
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close(fd);
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if (utmp.ut_type != USER_PROCESS) return;
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strncpy(utmp.ut_name, "", sizeof(utmp.ut_name));
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break;
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}
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/* Finish new utmp entry. */
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utmp.ut_pid = pid;
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utmp.ut_type = type;
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utmp.ut_time = time((time_t *) 0);
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/* Write new entry to utmp. */
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if ((fd = open(PATH_UTMP, O_WRONLY)) < 0
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|| lseek(fd, (off_t) (linenr+1) * sizeof(utmp), SEEK_SET) == -1
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|| write(fd, &utmp, sizeof(utmp)) == -1
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) {
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if (errno != ENOENT) report(PATH_UTMP);
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}
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if (fd != -1) close(fd);
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if (type == DEAD_PROCESS) {
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/* Add new wtmp entry. */
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if ((fd = open(PATH_WTMP, O_WRONLY | O_APPEND)) < 0
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|| write(fd, &utmp, sizeof(utmp)) == -1
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) {
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if (errno != ENOENT) report(PATH_WTMP);
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}
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if (fd != -1) close(fd);
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}
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}
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void report(label)
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char *label;
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{
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char message[128];
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sprintf(message, "telnetd: %s: %s\r\n", strerror(errno));
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(void) write(1, message, strlen(message));
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}
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