projects / unix-history / blob
? search:
summary | tags | clone url | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
watch for write failures to the net
[unix-history] / usr / src / usr.bin / telnet / telnet.c
static char sccsid[] = "@(#)telnet.c 4.7 (Berkeley) %G%";
/*
* User telnet program.
*/
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <sgtty.h>
#include <setjmp.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/in.h>
#define TELOPTS
#include "telnet.h"
#define ctrl(x) ((x) & 037)
#define strip(x) ((x)&0177)
#define INFINITY 10000000
#define swab(x) ((((x) >> 8) | ((x) << 8)) & 0xffff)
char ttyobuf[BUFSIZ], *tfrontp = ttyobuf, *tbackp = ttyobuf;
char netobuf[BUFSIZ] =
{ IAC, DO, TELOPT_ECHO, IAC, DO, TELOPT_SGA,
IAC, WONT, TELOPT_SGA },
*nfrontp = netobuf + 9, *nbackp = netobuf;
char hisopts[256];
char myopts[256];
char doopt[] = { IAC, DO, '%', 'c', 0 };
char dont[] = { IAC, DONT, '%', 'c', 0 };
char will[] = { IAC, WILL, '%', 'c', 0 };
char wont[] = { IAC, WONT, '%', 'c', 0 };
int connected;
int net;
int showoptions;
char *prompt;
char escape = ctrl('_');
char line[200];
int margc;
char *margv[20];
jmp_buf toplevel;
jmp_buf peerdied;
extern int errno;
int tn(), quit(), suspend(), bye(), help();
int setescape(), status(), toggle(), setoptions();
#define HELPINDENT (sizeof("connect"))
struct cmd {
char *name;
char *help;
int (*handler)();
};
char ohelp[] = "connect to a site";
char chelp[] = "close current connection";
char qhelp[] = "exit telnet";
char zhelp[] = "suspend telnet";
char ehelp[] = "set escape character";
char shelp[] = "print status information";
char hhelp[] = "print help information";
char phelp[] = "toggle viewing of options processing";
struct cmd cmdtab[] = {
{ "open", ohelp, tn },
{ "close", chelp, bye },
{ "quit", qhelp, quit },
{ "z", zhelp, suspend },
{ "escape", ehelp, setescape },
{ "status", shelp, status },
{ "options", phelp, setoptions },
{ "?", hhelp, help },
0
};
struct sockaddr_in sin = { AF_INET, swab(IPPORT_TELNET) };
int intr(), deadpeer();
char *control();
struct cmd *getcmd();
main(argc, argv)
int argc;
char *argv[];
{
setbuf(stdin, 0);
setbuf(stdout, 0);
prompt = argv[0];
if (argc != 1) {
if (setjmp(toplevel) != 0)
exit(0);
tn(argc, argv);
}
setjmp(toplevel);
for (;;)
command(1);
}
char host_name[100];
tn(argc, argv)
int argc;
char *argv[];
{
register int c;
if (connected) {
printf("?Already connected to %s\n", host_name);
return;
}
if (argc < 2) {
strcpy(line, "Connect ");
printf("(to) ");
gets(&line[strlen(line)]);
makeargv();
argc = margc;
argv = margv;
}
if (argc > 3) {
printf("usage: %s host-name [port]\n", argv[0]);
return;
}
sin.sin_addr.s_addr = rhost(&argv[1]);
if (sin.sin_addr.s_addr == (u_long)-1) {
printf("%s: unknown host\n", argv[1]);
return;
}
if (argc == 3) {
sin.sin_port = atoi(argv[2]);
if (sin.sin_port < 0) {
printf("%s: bad port number\n", argv[2]);
return;
}
}
if ((net = socket(SOCK_STREAM, 0, 0, 0)) < 0) {
perror("socket");
return;
}
sigset(SIGINT, intr);
sigset(SIGPIPE, deadpeer);
printf("Trying...\n");
if (connect(net, &sin)) {
perror("connect");
sigset(SIGINT, SIG_DFL);
return;
}
strcpy(host_name, argv[1]);
connected++;
call(status, "status", 0);
if (setjmp(peerdied) == 0)
telnet(net);
fprintf(stderr, "Connection closed by foreign host.\n");
exit(1);
}
/*
* Print status about the connection.
*/
/*VARARGS*/
status()
{
if (connected)
printf("Connected to %s.\n", host_name);
else
printf("No connection.\n");
printf("Escape character is '%s'.\n", control(escape));
}
makeargv()
{
register char *cp;
register char **argp = margv;
margc = 0;
for (cp = line; *cp;) {
while (isspace(*cp))
cp++;
if (*cp == '\0')
break;
*argp++ = cp;
margc += 1;
while (*cp != '\0' && !isspace(*cp))
cp++;
if (*cp == '\0')
break;
*cp++ = '\0';
}
*argp++ = 0;
}
/*VARARGS*/
suspend()
{
register int save;
save = mode(0);
kill(0, SIGTSTP); /* get whole process group */
mode(save);
}
/*VARARGS*/
bye()
{
int how = 2;
mode(0);
if (connected) {
ioctl(net, SIOCDONE, &how);
printf("Connection closed.\n");
close(net);
connected = 0;
}
}
/*VARARGS*/
quit()
{
call(bye, "bye", 0);
exit(0);
}
/*
* Help command.
* Call each command handler with argc == 0 and argv[0] == name.
*/
help(argc, argv)
int argc;
char *argv[];
{
register struct cmd *c;
if (argc == 1) {
printf("Commands may be abbreviated. Commands are:\n\n");
for (c = cmdtab; c->name; c++)
printf("%-*s\t%s\n", HELPINDENT, c->name, c->help);
return;
}
while (--argc > 0) {
register char *arg;
arg = *++argv;
c = getcmd(arg);
if (c == (struct cmd *)-1)
printf("?Ambiguous help command %s\n", arg);
else if (c == (struct cmd *)0)
printf("?Invalid help command %s\n", arg);
else
printf("%s\n", c->help);
}
}
/*
* Call routine with argc, argv set from args (terminated by 0).
* VARARGS2
*/
call(routine, args)
int (*routine)();
int args;
{
register int *argp;
register int argc;
for (argc = 0, argp = &args; *argp++ != 0; argc++)
;
(*routine)(argc, &args);
}
mode(f)
register int f;
{
register int old;
struct sgttyb stbuf;
static int ttymode = 0;
int onoff;
ioctl(fileno(stdin), TIOCGETP, &stbuf);
old = ttymode;
ttymode = f;
switch (f) {
case 0:
stbuf.sg_flags &= ~RAW;
stbuf.sg_flags |= ECHO|CRMOD;
onoff = 0;
break;
case 1:
stbuf.sg_flags |= RAW;
stbuf.sg_flags &= ~(ECHO|CRMOD);
onoff = 1;
break;
case 2:
stbuf.sg_flags |= RAW;
stbuf.sg_flags |= ECHO|CRMOD;
onoff = 1;
}
ioctl(fileno(stdin), TIOCSETN, &stbuf);
ioctl(fileno(stdin), FIONBIO, &onoff);
ioctl(fileno(stdout), FIONBIO, &onoff);
return (old);
}
char sibuf[BUFSIZ], *sbp;
char tibuf[BUFSIZ], *tbp;
int scc, tcc;
/*
* Select from tty and network...
*/
telnet(s)
int s;
{
register int c;
int tin = fileno(stdin), tout = fileno(stdout);
int on = 1;
mode(1);
if (showoptions)
printoption("<--", doopt, TELOPT_ECHO);
sprintf(nfrontp, doopt, TELOPT_ECHO);
nfrontp += sizeof(doopt) - 2;
hisopts[TELOPT_ECHO] = 1;
if (showoptions)
printoption("<--", doopt, TELOPT_SGA);
sprintf(nfrontp, doopt, TELOPT_SGA);
nfrontp += sizeof(doopt) - 2;
hisopts[TELOPT_SGA] = 1;
if (showoptions)
printoption("<--", will, TELOPT_SGA);
sprintf(nfrontp, will, TELOPT_SGA);
nfrontp += sizeof(doopt) - 2;
myopts[TELOPT_SGA] = 1;
ioctl(s, FIONBIO, &on);
for (;;) {
int ibits = 0, obits = 0;
if (nfrontp - nbackp)
obits |= (1 << s);
else
ibits |= (1 << tin);
if (tfrontp - tbackp)
obits |= (1 << tout);
else
ibits |= (1 << s);
if (scc < 0 && tcc < 0)
break;
select(32, &ibits, &obits, INFINITY);
if (ibits == 0 && obits == 0) {
sleep(5);
continue;
}
/*
* Something to read from the network...
*/
if (ibits & (1 << s)) {
scc = read(s, sibuf, sizeof(sibuf));
if (scc < 0 && errno == EWOULDBLOCK)
scc = 0;
else {
if (scc <= 0)
break;
sbp = sibuf;
}
}
/*
* Something to read from the tty...
*/
if (ibits & (1 << tin)) {
tcc = read(tin, tibuf, sizeof(tibuf));
if (tcc < 0 && errno == EWOULDBLOCK)
tcc = 0;
else {
if (tcc <= 0)
break;
tbp = tibuf;
}
}
while (tcc > 0) {
register int c;
if ((&netobuf[BUFSIZ] - nfrontp) < 2)
break;
c = *tbp++ & 0377, tcc--;
if (strip(c) == escape) {
command(0);
tcc = 0;
break;
}
*nfrontp++ = c;
}
if ((obits & (1 << s)) && (nfrontp - nbackp) > 0)
netflush(s);
if (scc > 0)
telrcv();
if ((obits & (1 << tout)) && (tfrontp - tbackp) > 0)
ttyflush(tout);
}
mode(0);
}
command(top)
int top;
{
register struct cmd *c;
int oldmode, wasopen;
oldmode = mode(0);
if (!top)
putchar('\n');
else
sigset(SIGINT, SIG_DFL);
for (;;) {
printf("%s> ", prompt);
if (gets(line) == 0)
break;
if (line[0] == 0)
break;
makeargv();
c = getcmd(margv[0]);
if (c == (struct cmd *)-1) {
printf("?Ambiguous command\n");
continue;
}
if (c == 0) {
printf("?Invalid command\n");
continue;
}
(*c->handler)(margc, margv);
if (c->handler != help)
break;
}
if (!top) {
if (!connected)
longjmp(toplevel, 1);
mode(oldmode);
}
}
/*
* Telnet receiver states for fsm
*/
#define TS_DATA 0
#define TS_IAC 1
#define TS_WILL 2
#define TS_WONT 3
#define TS_DO 4
#define TS_DONT 5
telrcv()
{
register int c;
static int state = TS_DATA;
while (scc > 0) {
c = *sbp++ & 0377, scc--;
switch (state) {
case TS_DATA:
if (c == IAC)
state = TS_IAC;
else
*tfrontp++ = c;
continue;
case TS_IAC:
switch (c) {
case WILL:
state = TS_WILL;
continue;
case WONT:
state = TS_WONT;
continue;
case DO:
state = TS_DO;
continue;
case DONT:
state = TS_DONT;
continue;
case DM:
ioctl(fileno(stdout), TIOCFLUSH, 0);
break;
case NOP:
case GA:
break;
default:
break;
}
state = TS_DATA;
continue;
case TS_WILL:
if (showoptions)
printoption("-->", will, c, !hisopts[c]);
if (!hisopts[c])
willoption(c);
state = TS_DATA;
continue;
case TS_WONT:
if (showoptions)
printoption("-->", wont, c, hisopts[c]);
if (hisopts[c])
wontoption(c);
state = TS_DATA;
continue;
case TS_DO:
if (showoptions)
printoption("-->", doopt, c, !myopts[c]);
if (!myopts[c])
dooption(c);
state = TS_DATA;
continue;
case TS_DONT:
if (showoptions)
printoption("-->", dont, c, myopts[c]);
if (myopts[c]) {
myopts[c] = 0;
sprintf(nfrontp, wont, c);
nfrontp += sizeof(wont) - 2;
if (showoptions)
printoption("<--", wont, c);
}
state = TS_DATA;
continue;
}
}
}
willoption(option)
int option;
{
char *fmt;
switch (option) {
case TELOPT_ECHO:
mode(1);
case TELOPT_SGA:
hisopts[option] = 1;
fmt = doopt;
break;
case TELOPT_TM:
fmt = dont;
break;
default:
fmt = dont;
break;
}
sprintf(nfrontp, fmt, option);
nfrontp += sizeof(dont) - 2;
if (showoptions)
printoption("<--", fmt, option);
}
wontoption(option)
int option;
{
char *fmt;
switch (option) {
case TELOPT_ECHO:
mode(2);
case TELOPT_SGA:
hisopts[option] = 0;
fmt = dont;
break;
default:
fmt = dont;
}
sprintf(nfrontp, fmt, option);
nfrontp += sizeof(doopt) - 2;
if (showoptions)
printoption("<--", fmt, option);
}
dooption(option)
int option;
{
char *fmt;
switch (option) {
case TELOPT_TM:
fmt = wont;
break;
case TELOPT_SGA:
fmt = will;
break;
default:
fmt = wont;
break;
}
sprintf(nfrontp, fmt, option);
nfrontp += sizeof(doopt) - 2;
if (showoptions)
printoption("<--", fmt, option);
}
/*
* Set the escape character.
*/
setescape(argc, argv)
int argc;
char *argv[];
{
register char *arg;
char buf[50];
if (argc > 2)
arg = argv[1];
else {
printf("new escape character: ");
gets(buf);
arg = buf;
}
if (arg[0] != '\0')
escape = arg[0];
printf("Escape character is '%s'.\n", control(escape));
}
/*VARARGS*/
setoptions()
{
showoptions = !showoptions;
printf("%s show option processing.\n", showoptions ? "Will" : "Wont");
}
/*
* Construct a control character sequence
* for a special character.
*/
char *
control(c)
register int c;
{
static char buf[3];
if (c == 0177)
return ("^?");
if (c >= 040) {
buf[0] = c;
buf[1] = 0;
} else {
buf[0] = '^';
buf[1] = '@'+c;
buf[2] = 0;
}
return (buf);
}
struct cmd *
getcmd(name)
register char *name;
{
register char *p, *q;
register struct cmd *c, *found;
register int nmatches, longest;
longest = 0;
nmatches = 0;
found = 0;
for (c = cmdtab; p = c->name; c++) {
for (q = name; *q == *p++; q++)
if (*q == 0) /* exact match? */
return (c);
if (!*q) { /* the name was a prefix */
if (q - name > longest) {
longest = q - name;
nmatches = 1;
found = c;
} else if (q - name == longest)
nmatches++;
}
}
if (nmatches > 1)
return ((struct cmd *)-1);
return (found);
}
deadpeer()
{
sigset(SIGPIPE, deadpeer);
mode(0);
longjmp(peerdied, -1);
}
intr()
{
sigset(SIGINT, intr);
mode(0);
longjmp(toplevel, -1);
}
ttyflush(fd)
{
int n;
if ((n = tfrontp - tbackp) > 0)
n = write(fd, tbackp, n);
if (n < 0 && errno == EWOULDBLOCK)
n = 0;
tbackp += n;
if (tbackp == tfrontp)
tbackp = tfrontp = ttyobuf;
}
netflush(fd)
{
int n;
if ((n = nfrontp - nbackp) > 0)
n = write(fd, nbackp, n);
if (n < 0) {
if (errno != ENOBUFS && errno != EWOULDBLOCK) {
mode(0);
perror(host_name);
close(fd);
longjmp(peerdied, -1);
/*NOTREACHED*/
}
n = 0;
}
nbackp += n;
if (nbackp == nfrontp)
nbackp = nfrontp = netobuf;
}
/*VARARGS*/
printoption(direction, fmt, option, what)
char *direction, *fmt;
int option, what;
{
printf("%s ", direction);
if (fmt == doopt)
fmt = "do";
else if (fmt == dont)
fmt = "dont";
else if (fmt == will)
fmt = "will";
else if (fmt == wont)
fmt = "wont";
else
fmt = "???";
if (option < TELOPT_SUPDUP)
printf("%s %s", fmt, telopts[option]);
else
printf("%s %d", fmt, option);
if (*direction == '<') {
printf("\r\n");
return;
}
printf(" (%s)\r\n", what ? "reply" : "don't reply");
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.