-/* telnetd.c 4.2 82/03/01 */
+#ifndef lint
+static char sccsid[] = "@(#)telnetd.c 4.9 82/10/10";
+#endif
/*
* Stripped-down telnet server.
#include <sys/types.h>
#include <sys/socket.h>
#include <net/in.h>
+#include <netdb.h>
#include "telnet.h"
#define INFINITY 10000000
#define BELL '\07'
-#define swab(x) ((((x) >> 8) | ((x) << 8)) & 0xffff)
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;
extern int errno;
char line[] = "/dev/ptyp0";
-struct sockaddr_in sin = { AF_INET, swab(IPPORT_TELNET) };
-int options = SO_ACCEPTCONN;
-
-/*
- * Debugging hooks. Turned on with a SIGTERM.
- * Successive SIGTERM's toggle the switch.
- */
-int toggle();
-int debug;
-FILE *log;
-char logfile[80] = "/tmp/teldebugx";
+struct sockaddr_in sin = { AF_INET };
+int options = SO_ACCEPTCONN|SO_KEEPALIVE;
main(argc, argv)
char *argv[];
{
int s, pid;
union wait status;
+ 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"))
- options |= SO_DEBUG;
+ options |= SO_DEBUG, 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);
+ }
+ }
+ sin.sin_port = htons(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
for (;;) {
errno = 0;
if ((s = socket(SOCK_STREAM, 0, &sin, options)) < 0) {
printf("All network ports in use.\n");
exit(1);
gotpty:
- logfile[strlen("/tmp/teldebug")] = "0123456789abcdef"[i];
dup2(f, 0);
cp[strlen("/dev/")] = 't';
t = open("/dev/tty", 2);
exit(1);
}
ioctl(t, TIOCGETP, &b);
- b.sg_flags = ECHO|CRMOD|XTABS|ANYP;
+ b.sg_flags = CRMOD|XTABS|ANYP;
ioctl(t, TIOCSETP, &b);
+ ioctl(p, TIOCGETP, &b);
+ b.sg_flags &= ~ECHO;
+ ioctl(p, TIOCSETP, &b);
if ((i = fork()) < 0) {
dup2(f, 2);
perror("fork");
ioctl(p, FIONBIO, &on);
signal(SIGTSTP, SIG_IGN);
sigset(SIGCHLD, cleanup);
- sigset(SIGTERM, toggle);
+ /*
+ * Request to do remote echo.
+ */
+ dooption(TELOPT_ECHO);
+ myopts[TELOPT_ECHO] = 1;
for (;;) {
int ibits = 0, obits = 0;
register int c;
ibits |= (1 << f);
if (ncc < 0 && pcc < 0)
break;
- if (debug)
- fprintf(log, "select: ibits=%d, obits=%d\n",
- ibits, obits);
select(32, &ibits, &obits, INFINITY);
- if (debug)
- fprintf(log, "ibits=%d, obits=%d\n", ibits, obits);
if (ibits == 0 && obits == 0) {
sleep(5);
continue;
*/
if (ibits & (1 << f)) {
ncc = read(f, netibuf, BUFSIZ);
- if (debug)
- fprintf(log, "read %d from net\n", ncc);
if (ncc < 0 && errno == EWOULDBLOCK)
ncc = 0;
else {
*/
if (ibits & (1 << p)) {
pcc = read(p, ptyibuf, BUFSIZ);
- if (debug)
- fprintf(log, "read %d from pty\n", pcc);
if (pcc < 0 && errno == EWOULDBLOCK)
pcc = 0;
else {
if (myopts[c]) {
myopts[c] = 0;
sprintf(nfrontp, wont, c);
- nfrontp += sizeof(wont) - 2;
+ nfrontp += sizeof (wont) - 2;
}
state = TS_DATA;
continue;
break;
}
sprintf(nfrontp, fmt, option);
- nfrontp += sizeof(dont) - 2;
+ 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;
}
-toggle()
-{
- if (debug) {
- fprintf(log, "log stopped\n");
- if (log)
- fclose(log);
- } else {
- if ((log = fopen(logfile, "a")) != NULL) {
- setbuf(log, 0);
- fprintf(log, "log started on /dev/pty%c\n",
- logfile[strlen("/tmp/teldebug")]);
- fprintf(log, "net=%d, pty=%d\n", net, pty);
- }
- }
- debug = !debug;
-}
-
cleanup()
{
int how = 2;
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, "");
time(&wtmp.ut_time);
- write(f, (char *)&wtmp, sizeof(wtmp));
+ write(f, (char *)&wtmp, sizeof (wtmp));
found++;
}
close(f);
SCPYN(wtmp.ut_name, "");
time(&wtmp.ut_time);
lseek(f, (long)0, 2);
- write(f, (char *)&wtmp, sizeof(wtmp));
+ write(f, (char *)&wtmp, sizeof (wtmp));
close(f);
}
}