-/* telnetd.c 4.1 82/02/28 */
+#ifndef lint
+static char sccsid[] = "@(#)telnetd.c 4.25 (Berkeley) 83/07/06";
+#endif
/*
* Stripped-down telnet server.
*/
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+
+#include <netinet/in.h>
+
+#include <arpa/telnet.h>
+
#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include <sgtty.h>
-#include <wait.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <net/in.h>
-#include "telnet.h"
+#include <netdb.h>
-#define INFINITY 10000000
-#define BELL '\07'
-#define swab(x) ((((x) >> 8) | ((x) << 8)) & 0xffff)
+#define BELL '\07'
+#define BANNER "\r\n\r\n4.2 BSD UNIX (%s)\r\n\r\r\n\r%s"
char hisopts[256];
char myopts[256];
char ptyibuf[BUFSIZ], *ptyip = ptyibuf;
char ptyobuf[BUFSIZ], *pfrontp = ptyobuf, *pbackp = ptyobuf;
char netibuf[BUFSIZ], *netip = netibuf;
-char netobuf[BUFSIZ] =
- { IAC, DO, TELOPT_ECHO, '\r', '\n' },
- *nfrontp = netobuf + 5, *nbackp = netobuf;
+char netobuf[BUFSIZ], *nfrontp = netobuf, *nbackp = netobuf;
int pcc, ncc;
int pty, net;
int inter;
+int reapchild();
+extern char **environ;
extern int errno;
char line[] = "/dev/ptyp0";
-struct sockaddr_in sin = { AF_INET, swab(IPPORT_TELNET) };
-int options = SO_ACCEPTCONN;
+struct sockaddr_in sin = { AF_INET };
main(argc, argv)
char *argv[];
{
- int s, pid;
- union wait status;
+ int s, pid, options;
+ struct servent *sp;
+ sp = getservbyname("telnet", "tcp");
+ if (sp == 0) {
+ fprintf(stderr, "telnetd: tcp/telnet: unknown service\n");
+ exit(1);
+ }
+ sin.sin_port = sp->s_port;
argc--, argv++;
- if (argc > 0 && !strcmp(argv[0], "-d"))
+ if (argc > 0 && !strcmp(*argv, "-d")) {
options |= SO_DEBUG;
- for (;;) {
- errno = 0;
- if ((s = socket(SOCK_STREAM, 0, &sin, options)) < 0) {
- perror("socket");
- sleep(5);
- continue;
+ argc--, argv++;
+ }
+ if (argc > 0) {
+ sin.sin_port = atoi(*argv);
+ if (sin.sin_port <= 0) {
+ fprintf(stderr, "telnetd: %s: bad port #\n", *argv);
+ exit(1);
}
- if (accept(s, 0) < 0) {
- perror("accept");
- close(s);
+ sin.sin_port = htons((u_short)sin.sin_port);
+ }
+#ifndef DEBUG
+ if (fork())
+ exit(0);
+ for (s = 0; s < 10; s++)
+ (void) close(s);
+ (void) open("/", 0);
+ (void) dup2(0, 1);
+ (void) dup2(0, 2);
+ { int tt = open("/dev/tty", 2);
+ if (tt > 0) {
+ ioctl(tt, TIOCNOTTY, 0);
+ close(tt);
+ }
+ }
+#endif
+again:
+ s = socket(AF_INET, SOCK_STREAM, 0, 0);
+ if (s < 0) {
+ perror("telnetd: socket");;
+ sleep(5);
+ goto again;
+ }
+ if (options & SO_DEBUG)
+ if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
+ perror("telnetd: setsockopt (SO_DEBUG)");
+ if (setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, 0, 0) < 0)
+ perror("telnetd: setsockopt (SO_KEEPALIVE)");
+ while (bind(s, (caddr_t)&sin, sizeof (sin), 0) < 0) {
+ perror("telnetd: bind");
+ sleep(5);
+ }
+ signal(SIGCHLD, reapchild);
+ listen(s, 10);
+ for (;;) {
+ struct sockaddr_in from;
+ int s2, fromlen = sizeof (from);
+
+ s2 = accept(s, (caddr_t)&from, &fromlen);
+ if (s2 < 0) {
+ if (errno == EINTR)
+ continue;
+ perror("telnetd: accept");
sleep(1);
continue;
}
if ((pid = fork()) < 0)
printf("Out of processes\n");
- else if (pid == 0)
- doit(s);
- close(s);
- while (wait3(status, WNOHANG, 0) > 0)
- continue;
+ else if (pid == 0) {
+ signal(SIGCHLD, SIG_IGN);
+ doit(s2, &from);
+ }
+ close(s2);
}
/*NOTREACHED*/
}
+reapchild()
+{
+ union wait status;
+
+ while (wait3(&status, WNOHANG, 0) > 0)
+ ;
+}
+
+char *envinit[] = { "TERM=network", 0 };
int cleanup();
/*
* Get a pty, scan input lines.
*/
-doit(f)
+doit(f, who)
+ int f;
+ struct sockaddr_in *who;
{
- char *cp = line;
+ char *cp = line, *host, *ntoa();
int i, p, cc, t;
struct sgttyb b;
+ struct hostent *hp;
for (i = 0; i < 16; i++) {
cp[strlen("/dev/ptyp")] = "0123456789abcdef"[i];
if (p > 0)
goto gotpty;
}
- dup2(f, 1);
- printf("All network ports in use.\n");
- exit(1);
+ fatal(f, "All network ports in use");
+ /*NOTREACHED*/
gotpty:
dup2(f, 0);
cp[strlen("/dev/")] = 't';
close(t);
}
t = open(cp, 2);
- if (t < 0) {
- dup2(f, 2);
- perror(cp);
- exit(1);
- }
+ if (t < 0)
+ fatalperror(f, cp, errno);
ioctl(t, TIOCGETP, &b);
- b.sg_flags = ECHO|CRMOD|XTABS|ANYP;
+ b.sg_flags = CRMOD|XTABS|ANYP;
ioctl(t, TIOCSETP, &b);
- if ((i = fork()) < 0) {
- dup2(f, 2);
- perror("fork");
- exit(1);
- }
+ ioctl(p, TIOCGETP, &b);
+ b.sg_flags &= ~ECHO;
+ ioctl(p, TIOCSETP, &b);
+ hp = gethostbyaddr(&who->sin_addr, sizeof (struct in_addr),
+ who->sin_family);
+ if (hp)
+ host = hp->h_name;
+ else
+ host = ntoa(who->sin_addr);
+ if ((i = fork()) < 0)
+ fatalperror(f, "fork", errno);
if (i)
telnet(f, p);
close(f);
dup2(t, 1);
dup2(t, 2);
close(t);
- execl("/bin/login", "telnet-login", 0);
- perror("/bin/login");
+ environ = envinit;
+ execl("/bin/login", "login", "-h", host, 0);
+ fatalperror(f, "/bin/login", errno);
+ /*NOTREACHED*/
+}
+
+fatal(f, msg)
+ int f;
+ char *msg;
+{
+ char buf[BUFSIZ];
+
+ (void) sprintf(buf, "telnetd: %s.\n", msg);
+ (void) write(f, buf, strlen(buf));
exit(1);
}
+fatalperror(f, msg, errno)
+ int f;
+ char *msg;
+ int errno;
+{
+ char buf[BUFSIZ];
+ extern char *sys_errlist[];
+
+ (void) sprintf(buf, "%s: %s", msg, sys_errlist[errno]);
+ fatal(f, buf);
+}
+
/*
* Main loop. Select from pty and network, and
* hand data to telnet receiver finite state machine.
telnet(f, p)
{
int on = 1;
+ char hostname[32];
net = f, pty = p;
ioctl(f, FIONBIO, &on);
ioctl(p, FIONBIO, &on);
signal(SIGTSTP, SIG_IGN);
- sigset(SIGCHLD, cleanup);
-
+ signal(SIGCHLD, cleanup);
+
+ /*
+ * Request to do remote echo.
+ */
+ dooption(TELOPT_ECHO);
+ myopts[TELOPT_ECHO] = 1;
+ /*
+ * Show banner that getty never gave.
+ */
+ gethostname(hostname, sizeof (hostname));
+ sprintf(nfrontp, BANNER, hostname, "");
+ nfrontp += strlen(nfrontp);
for (;;) {
int ibits = 0, obits = 0;
register int c;
ibits |= (1 << f);
if (ncc < 0 && pcc < 0)
break;
- select(32, &ibits, &obits, INFINITY);
+ select(16, &ibits, &obits, 0, 0);
if (ibits == 0 && obits == 0) {
sleep(5);
continue;
if (myopts[c]) {
myopts[c] = 0;
sprintf(nfrontp, wont, c);
- nfrontp += sizeof(wont) - 2;
+ nfrontp += sizeof (wont) - 2;
}
state = TS_DATA;
continue;
default:
- printf("netser: panic state=%d\n", state);
+ printf("telnetd: panic state=%d\n", state);
exit(1);
}
}
fmt = dont;
break;
}
- sprintf(nfrontp, dont, option);
- nfrontp += sizeof(dont) - 2;
+ sprintf(nfrontp, fmt, option);
+ nfrontp += sizeof (dont) - 2;
}
wontoption(option)
fmt = dont;
}
sprintf(nfrontp, fmt, option);
- nfrontp += sizeof(doopt) - 2;
+ nfrontp += sizeof (doopt) - 2;
}
dooption(option)
break;
}
sprintf(nfrontp, fmt, option);
- nfrontp += sizeof(doopt) - 2;
+ nfrontp += sizeof (doopt) - 2;
}
mode(on, off)
if ((n = pfrontp - pbackp) > 0)
n = write(pty, pbackp, n);
- if (n < 0 && errno == EWOULDBLOCK)
- n = 0;
+ if (n < 0)
+ return;
pbackp += n;
if (pbackp == pfrontp)
pbackp = pfrontp = ptyobuf;
if ((n = nfrontp - nbackp) > 0)
n = write(net, nbackp, n);
- if (n < 0 && errno == EWOULDBLOCK)
- n = 0;
+ if (n < 0) {
+ if (errno == EWOULDBLOCK)
+ return;
+ /* should blow this guy away... */
+ return;
+ }
nbackp += n;
if (nbackp == nfrontp)
nbackp = nfrontp = netobuf;
cleanup()
{
- int how = 2;
rmut();
- vhangup();
- ioctl(net, SIOCDONE, &how);
+ vhangup(); /* XXX */
+ shutdown(net, 2);
kill(0, SIGKILL);
exit(1);
}
struct utmp wtmp;
char wtmpf[] = "/usr/adm/wtmp";
char utmp[] = "/etc/utmp";
-#define SCPYN(a, b) strncpy(a, b, sizeof(a))
-#define SCMPN(a, b) strncmp(a, b, sizeof(a))
+#define SCPYN(a, b) strncpy(a, b, sizeof (a))
+#define SCMPN(a, b) strncmp(a, b, sizeof (a))
rmut()
{
f = open(utmp, 2);
if (f >= 0) {
- while(read(f, (char *)&wtmp, sizeof(wtmp)) == sizeof(wtmp)) {
+ while(read(f, (char *)&wtmp, sizeof (wtmp)) == sizeof (wtmp)) {
if (SCMPN(wtmp.ut_line, line+5) || wtmp.ut_name[0]==0)
continue;
- lseek(f, -(long)sizeof(wtmp), 1);
+ lseek(f, -(long)sizeof (wtmp), 1);
SCPYN(wtmp.ut_name, "");
+ SCPYN(wtmp.ut_host, "");
time(&wtmp.ut_time);
- write(f, (char *)&wtmp, sizeof(wtmp));
+ write(f, (char *)&wtmp, sizeof (wtmp));
found++;
}
close(f);
if (f >= 0) {
SCPYN(wtmp.ut_line, line+5);
SCPYN(wtmp.ut_name, "");
+ SCPYN(wtmp.ut_host, "");
time(&wtmp.ut_time);
lseek(f, (long)0, 2);
- write(f, (char *)&wtmp, sizeof(wtmp));
+ write(f, (char *)&wtmp, sizeof (wtmp));
close(f);
}
}
chmod(line, 0666);
chown(line, 0, 0);
}
+
+/*
+ * Convert network-format internet address
+ * to base 256 d.d.d.d representation.
+ */
+char *
+ntoa(in)
+ struct in_addr in;
+{
+ static char b[18];
+ register char *p;
+
+ p = (char *)∈
+#define UC(b) (((int)b)&0xff)
+ sprintf(b, "%d.%d.%d.%d", UC(p[0]), UC(p[1]), UC(p[2]), UC(p[3]));
+ return (b);
+}