/*      $NetBSD: commands.c,v 1.80 2022/07/08 21:51:24 mlelstv Exp $    */

/*
* Copyright (C) 1997 and 1998 WIDE Project.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

/*
* Copyright (c) 1988, 1990, 1993
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)commands.c  8.4 (Berkeley) 5/30/95";
#else
__RCSID("$NetBSD: commands.c,v 1.80 2022/07/08 21:51:24 mlelstv Exp $");
#endif
#endif /* not lint */

#include <sys/param.h>
#include <sys/file.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <pwd.h>
#include <signal.h>
#include <stdarg.h>
#include <unistd.h>
#include <err.h>

#include <arpa/telnet.h>

#include "general.h"
#include "ring.h"
#include "externs.h"
#include "defines.h"
#include "types.h"
#include <libtelnet/misc.h>
#ifdef AUTHENTICATION
#include <libtelnet/auth.h>
#endif
#ifdef ENCRYPTION
#include <libtelnet/encrypt.h>
#endif

#include <netinet/in_systm.h>
#include <netinet/ip.h>


#if     defined(IPPROTO_IP) && defined(IP_TOS)
int tos = -1;
#endif  /* defined(IPPROTO_IP) && defined(IP_TOS) */

char    *hostname;
static char _hostname[MAXHOSTNAMELEN];

typedef struct {
       const char      *name;  /* command name */
       const char      *help;  /* help string (NULL for no help) */
       int     (*handler)      /* routine which executes command */
                       (int, char *[]);
       int     needconnect;    /* Do we need to be connected to execute? */
} Command;

static char line[256];
static char saveline[256];
static int margc;
static char *margv[20];

static void makeargv(void);
static int special(const char *);
static const char *control(cc_t);
static int sendcmd(int, char **);
static int send_esc(const char *);
static int send_docmd(const char *);
static int send_dontcmd(const char *);
static int send_willcmd(const char *);
static int send_wontcmd(const char *);
static int send_help(const char *);
static int lclchars(int);
static int togdebug(int);
static int togcrlf(int);
static int togbinary(int);
static int togrbinary(int);
static int togxbinary(int);
static int togglehelp(int);
static void settogglehelp(int);
static int toggle(int, char *[]);
static struct setlist *getset(const char *);
static int setcmd(int, char *[]);
static int unsetcmd(int, char *[]);
static int dokludgemode(int);
static int dolinemode(int);
static int docharmode(int);
static int dolmmode(int, int );
static int modecmd(int, char *[]);
static int display(int, char *[]);
static int setescape(int, char *[]);
static int togcrmod(int, char *[]);
static int bye(int, char *[]);
static void slc_help(int);
static struct slclist *getslc(const char *);
static int slccmd(int, char *[]);
static struct env_lst *env_help(const char *, char *);
static struct envlist *getenvcmd(const char *);
#ifdef AUTHENTICATION
static int auth_help(const char *);
#endif
static int status(int, char *[]);
static const char *sockaddr_ntop (struct sockaddr *);
typedef int (*intrtn_t)(int, char **);
static int call(intrtn_t, ...);
static Command *getcmd(const char *);
static int help(int, char *[]);

static int
addarg(char *str)
{
       if ((size_t)margc >= __arraycount(margv) - 1)
               return 0;
       margv[margc++] = str;
       margv[margc] = NULL;
       return 1;
}


static void
makeargv(void)
{
   char *cp, *cp2, c;
   static char bang[] = "!";

   margc = 0;
   margv[0] = NULL;
   cp = line;
   if (*cp == '!') {           /* Special case shell escape */
       /* save for shell command */
       strlcpy(saveline, line, sizeof(saveline));
       if (!addarg(bang))
           return;
       cp++;
   }
   while ((c = *cp) != '\0') {
       int inquote = 0;
       while (isspace((unsigned char)c))
           c = *++cp;
       if (c == '\0')
           break;
       if (!addarg(cp))
           return;
       for (cp2 = cp; c != '\0'; c = *++cp) {
           if (inquote) {
               if (c == inquote) {
                   inquote = 0;
                   continue;
               }
           } else {
               if (c == '\\') {
                   if ((c = *++cp) == '\0')
                       break;
               } else if (c == '"' || c == '\'') {
                   inquote = c;
                   continue;
               } else if (isspace((unsigned char)c))
                   break;
           }
           *cp2++ = c;
       }
       *cp2 = '\0';
       if (c == '\0')
           break;
       cp++;
   }
}

/*
* Make a character string into a number.
*
* Todo:  1.  Could take random integers (12, 0x12, 012, 0b1).
*/

static int
special(const char *s)
{
       char c;
       char b;

       switch (*s) {
       case '^':
               b = *++s;
               if (b == '?') {
                   c = b | 0x40;               /* DEL */
               } else {
                   c = b & 0x1f;
               }
               break;
       default:
               c = *s;
               break;
       }
       return c;
}

/*
* Construct a control character sequence
* for a special character.
*/
static const char *
control(cc_t c)
{
       static char buf[5];
       /*
        * The only way I could get the Sun 3.5 compiler
        * to shut up about
        *      if ((unsigned int)c >= 0x80)
        * was to assign "c" to an unsigned int variable...
        * Arggg....
        */
       unsigned int uic = (unsigned int)c;

       if (uic == 0x7f)
               return ("^?");
       if (c == (cc_t)_POSIX_VDISABLE) {
               return "off";
       }
       if (uic >= 0x80) {
               buf[0] = '\\';
               buf[1] = ((c >> 6) & 07) + '0';
               buf[2] = ((c >> 3) & 07) + '0';
               buf[3] = (c & 07) + '0';
               buf[4] = '\0';
       } else if (uic >= 0x20) {
               buf[0] = c;
               buf[1] = '\0';
       } else {
               buf[0] = '^';
               buf[1] = '@' + c;
               buf[2] = '\0';
       }
       return (buf);
}



/*
*      The following are data structures and routines for
*      the "send" command.
*
*/

struct sendlist {
   const char  *name;          /* How user refers to it (case independent) */
   const char  *help;          /* Help information (0 ==> no help) */
   int         needconnect;    /* Need to be connected */
   int         narg;           /* Number of arguments */
   int         (*handler)      /* Routine to perform (for special ops) */
                       (const char *);
   int         nbyte;          /* Number of bytes to send this command */
   int         what;           /* Character to be sent (<0 ==> special) */
};


static struct sendlist Sendlist[] = {
   { "ao",     "Send Telnet Abort output",             1, 0, 0, 2, AO },
   { "ayt",    "Send Telnet 'Are You There'",          1, 0, 0, 2, AYT },
   { "brk",    "Send Telnet Break",                    1, 0, 0, 2, BREAK },
   { "break",  0,                                      1, 0, 0, 2, BREAK },
   { "ec",     "Send Telnet Erase Character",          1, 0, 0, 2, EC },
   { "el",     "Send Telnet Erase Line",               1, 0, 0, 2, EL },
   { "escape", "Send current escape character",        1, 0, send_esc, 1, 0 },
   { "ga",     "Send Telnet 'Go Ahead' sequence",      1, 0, 0, 2, GA },
   { "ip",     "Send Telnet Interrupt Process",        1, 0, 0, 2, IP },
   { "intp",   0,                                      1, 0, 0, 2, IP },
   { "interrupt", 0,                                   1, 0, 0, 2, IP },
   { "intr",   0,                                      1, 0, 0, 2, IP },
   { "nop",    "Send Telnet 'No operation'",           1, 0, 0, 2, NOP },
   { "eor",    "Send Telnet 'End of Record'",          1, 0, 0, 2, EOR },
   { "abort",  "Send Telnet 'Abort Process'",          1, 0, 0, 2, ABORT },
   { "susp",   "Send Telnet 'Suspend Process'",        1, 0, 0, 2, SUSP },
   { "eof",    "Send Telnet End of File Character",    1, 0, 0, 2, xEOF },
   { "synch",  "Perform Telnet 'Synch operation'",     1, 0, dosynch, 2, 0 },
   { "getstatus", "Send request for STATUS",           1, 0, get_status, 6, 0 },
   { "?",      "Display send options",                 0, 0, send_help, 0, 0 },
   { "help",   0,                                      0, 0, send_help, 0, 0 },
   { "do",     0,                                      0, 1, send_docmd, 3, 0 },
   { "dont",   0,                                      0, 1, send_dontcmd, 3, 0 },
   { "will",   0,                                      0, 1, send_willcmd, 3, 0 },
   { "wont",   0,                                      0, 1, send_wontcmd, 3, 0 },
   { .name = 0 }
};

#define GETSEND(name) ((struct sendlist *) genget(name, (char **) Sendlist, \
                               sizeof(struct sendlist)))

static int
sendcmd(int  argc, char **argv)
{
   int count;          /* how many bytes we are going to need to send */
   int i;
   struct sendlist *s; /* pointer to current command */
   int success = 0;
   int needconnect = 0;

   if (argc < 2) {
       printf("need at least one argument for 'send' command\n");
       printf("'send ?' for help\n");
       return 0;
   }
   /*
    * First, validate all the send arguments.
    * In addition, we see how much space we are going to need, and
    * whether or not we will be doing a "SYNCH" operation (which
    * flushes the network queue).
    */
   count = 0;
   for (i = 1; i < argc; i++) {
       s = GETSEND(argv[i]);
       if (s == 0) {
           printf("Unknown send argument '%s'\n'send ?' for help.\n",
                       argv[i]);
           return 0;
       } else if (Ambiguous(s)) {
           printf("Ambiguous send argument '%s'\n'send ?' for help.\n",
                       argv[i]);
           return 0;
       }
       if (i + s->narg >= argc) {
           fprintf(stderr,
           "Need %d argument%s to 'send %s' command.  'send %s ?' for help.\n",
               s->narg, s->narg == 1 ? "" : "s", s->name, s->name);
           return 0;
       }
       count += s->nbyte;
       if (s->handler == send_help) {
           send_help(NULL);
           return 0;
       }

       i += s->narg;
       needconnect += s->needconnect;
   }
   if (!connected && needconnect) {
       printf("?Need to be connected first.\n");
       printf("'send ?' for help\n");
       return 0;
   }
   /* Now, do we have enough room? */
   if (NETROOM() < count) {
       printf("There is not enough room in the buffer TO the network\n");
       printf("to process your request.  Nothing will be done.\n");
       printf("('send synch' will throw away most data in the network\n");
       printf("buffer, if this might help.)\n");
       return 0;
   }
   /* OK, they are all OK, now go through again and actually send */
   count = 0;
   for (i = 1; i < argc; i++) {
       if ((s = GETSEND(argv[i])) == 0) {
           fprintf(stderr, "Telnet 'send' error - argument disappeared!\n");
           (void) quit(0, NULL);
           /*NOTREACHED*/
       }
       if (s->handler) {
           count++;
           success += (*s->handler)(argv[i+1]);
           i += s->narg;
       } else {
           NET2ADD(IAC, (unsigned char)s->what);
           printoption("SENT", IAC, s->what);
       }
   }
   return (count == success);
}

static int
send_esc(const char *s)
{
   NETADD(escape);
   return 1;
}

static int
send_docmd(const char *name)
{
   return send_tncmd(send_do, "do", name);
}

static int
send_dontcmd(const char *name)
{
   return send_tncmd(send_dont, "dont", name);
}

static int
send_willcmd(const char *name)
{
   return send_tncmd(send_will, "will", name);
}

static int
send_wontcmd(const char *name)
{
   return send_tncmd(send_wont, "wont", name);
}

int
send_tncmd(void (*func)(int, int), const char   *cmd, const char *name)
{
   const char **cpp;
   ptrdiff_t val = 0;

   if (isprefix(name, "?")) {
       size_t col, len;

       printf("usage: send %s <value|option>\n", cmd);
       printf("\"value\" must be from 0 to 255\n");
       printf("Valid options are:\n\t");

       col = 8;
       for (cpp = telopts; *cpp; cpp++) {
           len = strlen(*cpp) + 3;
           if (col + len > 65) {
               printf("\n\t");
               col = 8;
           }
           printf(" \"%s\"", *cpp);
           col += len;
       }
       printf("\n");
       return 0;
   }
   cpp = (void *)genget(name, __UNCONST(telopts), sizeof(char *));
   if (Ambiguous(cpp)) {
       fprintf(stderr,"'%s': ambiguous argument ('send %s ?' for help).\n",
                                       name, cmd);
       return 0;
   }
   if (cpp) {
       val = cpp - telopts;
   } else {
       const char *cp = name;

       while (*cp >= '0' && *cp <= '9') {
           val *= 10;
           val += *cp - '0';
           cp++;
       }
       if (*cp != 0) {
           fprintf(stderr, "'%s': unknown argument ('send %s ?' for help).\n",
                                       name, cmd);
           return 0;
       } else if (val < 0 || val > 255) {
           fprintf(stderr, "'%s': bad value ('send %s ?' for help).\n",
                                       name, cmd);
           return 0;
       }
   }
   if (!connected) {
       printf("?Need to be connected first.\n");
       return 0;
   }
   (*func)((int)val, 1);
   return 1;
}

static int
send_help(const char *n)
{
   struct sendlist *s; /* pointer to current command */
   for (s = Sendlist; s->name; s++) {
       if (s->help)
           printf("%-15s %s\n", s->name, s->help);
   }
   return 0;
}

/*
* The following are the routines and data structures referred
* to by the arguments to the "toggle" command.
*/

static int
lclchars(int n)
{
   donelclchars = 1;
   return 1;
}

static int
togdebug(int n)
{
   if (net > 0 &&
       (SetSockOpt(net, SOL_SOCKET, SO_DEBUG, telnet_debug)) < 0) {
           warn("setsockopt (SO_DEBUG)");
   }
   return 1;
}

static int
togcrlf(int n)
{
   if (crlf) {
       printf("Will send carriage returns as telnet <CR><LF>.\n");
   } else {
       printf("Will send carriage returns as telnet <CR><NUL>.\n");
   }
   return 1;
}

int binmode;

static int
togbinary(int val)
{
   donebinarytoggle = 1;

   if (val >= 0) {
       binmode = val;
   } else {
       if (my_want_state_is_will(TELOPT_BINARY) &&
                               my_want_state_is_do(TELOPT_BINARY)) {
           binmode = 1;
       } else if (my_want_state_is_wont(TELOPT_BINARY) &&
                               my_want_state_is_dont(TELOPT_BINARY)) {
           binmode = 0;
       }
       val = binmode ? 0 : 1;
   }

   if (val == 1) {
       if (my_want_state_is_will(TELOPT_BINARY) &&
                                       my_want_state_is_do(TELOPT_BINARY)) {
           printf("Already operating in binary mode with remote host.\n");
       } else {
           printf("Negotiating binary mode with remote host.\n");
           tel_enter_binary(3);
       }
   } else {
       if (my_want_state_is_wont(TELOPT_BINARY) &&
                                       my_want_state_is_dont(TELOPT_BINARY)) {
           printf("Already in network ascii mode with remote host.\n");
       } else {
           printf("Negotiating network ascii mode with remote host.\n");
           tel_leave_binary(3);
       }
   }
   return 1;
}

static int
togrbinary(int val)
{
   donebinarytoggle = 1;

   if (val == -1)
       val = my_want_state_is_do(TELOPT_BINARY) ? 0 : 1;

   if (val == 1) {
       if (my_want_state_is_do(TELOPT_BINARY)) {
           printf("Already receiving in binary mode.\n");
       } else {
           printf("Negotiating binary mode on input.\n");
           tel_enter_binary(1);
       }
   } else {
       if (my_want_state_is_dont(TELOPT_BINARY)) {
           printf("Already receiving in network ascii mode.\n");
       } else {
           printf("Negotiating network ascii mode on input.\n");
           tel_leave_binary(1);
       }
   }
   return 1;
}

static int
togxbinary(int val)
{
   donebinarytoggle = 1;

   if (val == -1)
       val = my_want_state_is_will(TELOPT_BINARY) ? 0 : 1;

   if (val == 1) {
       if (my_want_state_is_will(TELOPT_BINARY)) {
           printf("Already transmitting in binary mode.\n");
       } else {
           printf("Negotiating binary mode on output.\n");
           tel_enter_binary(2);
       }
   } else {
       if (my_want_state_is_wont(TELOPT_BINARY)) {
           printf("Already transmitting in network ascii mode.\n");
       } else {
           printf("Negotiating network ascii mode on output.\n");
           tel_leave_binary(2);
       }
   }
   return 1;
}

#ifdef  ENCRYPTION
extern int EncryptAutoEnc(int);
extern int EncryptAutoDec(int);
extern int EncryptDebug(int);
extern int EncryptVerbose(int);
#endif  /* ENCRYPTION */

struct togglelist {
   const char  *name;          /* name of toggle */
   const char  *help;          /* help message */
   int         (*handler)      /* routine to do actual setting */
                       (int);
   int         *variable;
   const char  *actionexplanation;
};

static struct togglelist Togglelist[] = {
   { "autoflush",
       "flushing of output when sending interrupt characters",
           0,
               &autoflush,
                   "flush output when sending interrupt characters" },
   { "autosynch",
       "automatic sending of interrupt characters in urgent mode",
           0,
               &autosynch,
                   "send interrupt characters in urgent mode" },
#ifdef AUTHENTICATION
   { "autologin",
       "automatic sending of login and/or authentication info",
           0,
               &autologin,
                   "send login name and/or authentication information" },
   { "authdebug",
       "Toggle authentication debugging",
           auth_togdebug,
               0,
                    "print authentication debugging information" },
#endif
#ifdef  ENCRYPTION
   { "autoencrypt",
     "automatic encryption of data stream",
           EncryptAutoEnc,
               0,
                    "automatically encrypt output" },
   { "autodecrypt",
     "automatic decryption of data stream",
           EncryptAutoDec,
               0,
                    "automatically decrypt input" },
   { "verbose_encrypt",
     "Toggle verbose encryption output",
           EncryptVerbose,
               0,
                    "print verbose encryption output" },
   { "encdebug",
     "Toggle encryption debugging",
           EncryptDebug,
               0,
                    "print encryption debugging information" },
#endif  /* ENCRYPTION */
   { "skiprc",
       "don't read ~/.telnetrc file",
           0,
               &skiprc,
                   "skip reading of ~/.telnetrc file" },
   { "binary",
       "sending and receiving of binary data",
           togbinary,
               0,
                   0 },
   { "inbinary",
       "receiving of binary data",
           togrbinary,
               0,
                   0 },
   { "outbinary",
       "sending of binary data",
           togxbinary,
               0,
                   0 },
   { "crlf",
       "sending carriage returns as telnet <CR><LF>",
          togcrlf,
               &crlf,
                   0 },
   { "crmod",
       "mapping of received carriage returns",
           0,
               &crmod,
                   "map carriage return on output" },
   { "localchars",
       "local recognition of certain control characters",
           lclchars,
               &localchars,
                   "recognize certain control characters" },
   { " ", "", 0, NULL, NULL },         /* empty line */
   { "debug",
       "debugging",
           togdebug,
               &telnet_debug,
                   "turn on socket level debugging" },
   { "netdata",
       "printing of hexadecimal network data (debugging)",
           0,
               &netdata,
                   "print hexadecimal representation of network traffic" },
   { "prettydump",
       "output of \"netdata\" to user readable format (debugging)",
           0,
               &prettydump,
                   "print user readable output for \"netdata\"" },
   { "options",
       "viewing of options processing (debugging)",
           0,
               &showoptions,
                   "show option processing" },
   { "termdata",
       "(debugging) toggle printing of hexadecimal terminal data",
           0,
               &termdata,
                   "print hexadecimal representation of terminal traffic" },
   { "?",
       0,
           togglehelp, NULL, NULL },
   { "help",
       0,
           togglehelp, NULL, NULL },
   { .name = 0 }
};

static int
togglehelp(int n)
{
   struct togglelist *c;

   for (c = Togglelist; c->name; c++) {
       if (c->help) {
           if (*c->help)
               printf("%-15s toggle %s\n", c->name, c->help);
           else
               printf("\n");
       }
   }
   printf("\n");
   printf("%-15s %s\n", "?", "display help information");
   return 0;
}

static void
settogglehelp(int set)
{
   struct togglelist *c;

   for (c = Togglelist; c->name; c++) {
       if (c->help) {
           if (*c->help)
               printf("%-15s %s %s\n", c->name, set ? "enable" : "disable",
                                               c->help);
           else
               printf("\n");
       }
   }
}

#define GETTOGGLE(name) (struct togglelist *) \
               genget(name, (char **) Togglelist, sizeof(struct togglelist))

static int
toggle(int  argc, char *argv[])
{
   int retval = 1;
   char *name;
   struct togglelist *c;

   if (argc < 2) {
       fprintf(stderr,
           "Need an argument to 'toggle' command.  'toggle ?' for help.\n");
       return 0;
   }
   argc--;
   argv++;
   while (argc--) {
       name = *argv++;
       c = GETTOGGLE(name);
       if (Ambiguous(c)) {
           fprintf(stderr, "'%s': ambiguous argument ('toggle ?' for help).\n",
                                       name);
           return 0;
       } else if (c == 0) {
           fprintf(stderr, "'%s': unknown argument ('toggle ?' for help).\n",
                                       name);
           return 0;
       } else {
           if (c->variable) {
               *c->variable = !*c->variable;           /* invert it */
               if (c->actionexplanation) {
                   printf("%s %s.\n", *c->variable? "Will" : "Won't",
                                                       c->actionexplanation);
               }
           }
           if (c->handler) {
               retval &= (*c->handler)(-1);
           }
       }
   }
   return retval;
}

/*
* The following perform the "set" command.
*/

struct termios new_tc = { .c_iflag = 0 };

struct setlist {
   const char *name;                   /* name */
   const char *help;                   /* help information */
   void (*handler)(const char *);
   cc_t *charp;                        /* where it is located at */
};

static struct setlist Setlist[] = {
#ifdef  KLUDGELINEMODE
   { "echo",   "character to toggle local echoing on/off", 0, &echoc },
#endif
   { "escape", "character to escape back to telnet command mode", 0, &escape },
   { "rlogin", "rlogin escape character", 0, &rlogin },
   { "tracefile", "file to write trace information to", SetNetTrace, (cc_t *)NetTraceFile},
   { " ", "", NULL, NULL },
   { " ", "The following need 'localchars' to be toggled true", 0, 0 },
   { "flushoutput", "character to cause an Abort Output", 0, termFlushCharp },
   { "interrupt", "character to cause an Interrupt Process", 0, termIntCharp },
   { "quit",   "character to cause an Abort process", 0, termQuitCharp },
   { "eof",    "character to cause an EOF ", 0, termEofCharp },
   { " ", "", NULL, NULL },
   { " ", "The following are for local editing in linemode", 0, 0 },
   { "erase",  "character to use to erase a character", 0, termEraseCharp },
   { "kill",   "character to use to erase a line", 0, termKillCharp },
   { "lnext",  "character to use for literal next", 0, termLiteralNextCharp },
   { "susp",   "character to cause a Suspend Process", 0, termSuspCharp },
   { "reprint", "character to use for line reprint", 0, termRprntCharp },
   { "worderase", "character to use to erase a word", 0, termWerasCharp },
   { "start",  "character to use for XON", 0, termStartCharp },
   { "stop",   "character to use for XOFF", 0, termStopCharp },
   { "forw1",  "alternate end of line character", 0, termForw1Charp },
   { "forw2",  "alternate end of line character", 0, termForw2Charp },
   { "ayt",    "alternate AYT character", 0, termAytCharp },
   { .name = 0 }
};

static struct setlist *
getset(const char *name)
{
   return (struct setlist *)
               genget(name, (char **) Setlist, sizeof(struct setlist));
}

static cc_t
getcc(const char *s)
{
       return (cc_t)((s && *s) ? special(s) : _POSIX_VDISABLE);
}

void
set_escape_char(char *s)
{
       if (rlogin != _POSIX_VDISABLE) {
               rlogin = getcc(s);
               printf("Telnet rlogin escape character is '%s'.\n",
                                       control(rlogin));
       } else {
               escape = getcc(s);
               printf("Telnet escape character is '%s'.\n", control(escape));
       }
}

static int
setcmd(int  argc, char *argv[])
{
   int value;
   struct setlist *ct;
   struct togglelist *c;

   if (argc < 2 || argc > 3) {
       printf("Format is 'set Name Value'\n'set ?' for help.\n");
       return 0;
   }
   if ((argc == 2) && (isprefix(argv[1], "?") || isprefix(argv[1], "help"))) {
       for (ct = Setlist; ct->name; ct++)
           printf("%-15s %s\n", ct->name, ct->help);
       printf("\n");
       settogglehelp(1);
       printf("%-15s %s\n", "?", "display help information");
       return 0;
   }

   ct = getset(argv[1]);
   if (ct == 0 || !(ct->name && ct->name[0] != ' ')) {
       c = GETTOGGLE(argv[1]);
       if (c == 0) {
           fprintf(stderr, "'%s': unknown argument ('set ?' for help).\n",
                       argv[1]);
           return 0;
       } else if (Ambiguous(c)) {
           fprintf(stderr, "'%s': ambiguous argument ('set ?' for help).\n",
                       argv[1]);
           return 0;
       }
       if (c->variable) {
           if ((argc == 2) || (strcmp("on", argv[2]) == 0))
               *c->variable = 1;
           else if (strcmp("off", argv[2]) == 0)
               *c->variable = 0;
           else {
               printf("Format is 'set togglename [on|off]'\n'set ?' for help.\n");
               return 0;
           }
           if (c->actionexplanation) {
               printf("%s %s.\n", *c->variable? "Will" : "Won't",
                                                       c->actionexplanation);
           }
       }
       if (c->handler)
           (*c->handler)(1);
   } else if (argc != 3) {
       printf("Format is 'set Name Value'\n'set ?' for help.\n");
       return 0;
   } else if (Ambiguous(ct)) {
       fprintf(stderr, "'%s': ambiguous argument ('set ?' for help).\n",
                       argv[1]);
       return 0;
   } else if (ct->handler) {
       (*ct->handler)(argv[2]);
       printf("%s set to \"%s\".\n", ct->name, ct->charp);
   } else {
       if (strcmp("off", argv[2])) {
           value = special(argv[2]);
       } else {
           value = _POSIX_VDISABLE;
       }
       *(ct->charp) = (cc_t)value;
       printf("%s character is '%s'.\n", ct->name, control(*(ct->charp)));
   }
   slc_check();
   return 1;
}

static int
unsetcmd(int  argc, char *argv[])
{
   struct setlist *ct;
   struct togglelist *c;
   char *name;

   if (argc < 2) {
       fprintf(stderr,
           "Need an argument to 'unset' command.  'unset ?' for help.\n");
       return 0;
   }
   if (isprefix(argv[1], "?") || isprefix(argv[1], "help")) {
       for (ct = Setlist; ct->name; ct++)
           printf("%-15s %s\n", ct->name, ct->help);
       printf("\n");
       settogglehelp(0);
       printf("%-15s %s\n", "?", "display help information");
       return 0;
   }

   argc--;
   argv++;
   while (argc--) {
       name = *argv++;
       ct = getset(name);
       if (ct == 0 || !(ct->name && ct->name[0] != ' ')) {
           c = GETTOGGLE(name);
           if (c == 0) {
               fprintf(stderr, "'%s': unknown argument ('unset ?' for help).\n",
                       name);
               return 0;
           } else if (Ambiguous(c)) {
               fprintf(stderr, "'%s': ambiguous argument ('unset ?' for help).\n",
                       name);
               return 0;
           }
           if (c->variable) {
               *c->variable = 0;
               if (c->actionexplanation) {
                   printf("%s %s.\n", *c->variable? "Will" : "Won't",
                                                       c->actionexplanation);
               }
           }
           if (c->handler)
               (*c->handler)(0);
       } else if (Ambiguous(ct)) {
           fprintf(stderr, "'%s': ambiguous argument ('unset ?' for help).\n",
                       name);
           return 0;
       } else if (ct->handler) {
           (*ct->handler)(0);
           printf("%s reset to \"%s\".\n", ct->name, ct->charp);
       } else {
           *(ct->charp) = _POSIX_VDISABLE;
           printf("%s character is '%s'.\n", ct->name, control(*(ct->charp)));
       }
   }
   return 1;
}

/*
* The following are the data structures and routines for the
* 'mode' command.
*/
#ifdef  KLUDGELINEMODE
extern int kludgelinemode;

static int
dokludgemode(int n)
{
   kludgelinemode = 1;
   send_wont(TELOPT_LINEMODE, 1);
   send_dont(TELOPT_SGA, 1);
   send_dont(TELOPT_ECHO, 1);
   return 1;
}
#endif

static int
dolinemode(int n)
{
#ifdef  KLUDGELINEMODE
   if (kludgelinemode)
       send_dont(TELOPT_SGA, 1);
#endif
   send_will(TELOPT_LINEMODE, 1);
   send_dont(TELOPT_ECHO, 1);
   return 1;
}

static int
docharmode(int n)
{
#ifdef  KLUDGELINEMODE
   if (kludgelinemode)
       send_do(TELOPT_SGA, 1);
   else
#endif
   send_wont(TELOPT_LINEMODE, 1);
   send_do(TELOPT_ECHO, 1);
   return 1;
}

static int
dolmmode(int bit, int on)
{
   unsigned char c;
   extern int linemode;

   if (my_want_state_is_wont(TELOPT_LINEMODE)) {
       printf("?Need to have LINEMODE option enabled first.\n");
       printf("'mode ?' for help.\n");
       return 0;
   }

   if (on)
       c = (unsigned char)(linemode | bit);
   else
       c = (unsigned char)(linemode & ~bit);
   lm_mode(&c, 1, 1);
   return 1;
}

int
set_mode(int bit)
{
   return dolmmode(bit, 1);
}

int
clear_mode(int bit)
{
   return dolmmode(bit, 0);
}

struct modelist {
       const char      *name;  /* command name */
       const char      *help;  /* help string */
       int     (*handler)      /* routine which executes command */
                       (int);
       int     needconnect;    /* Do we need to be connected to execute? */
       int     arg1;
};

static struct modelist ModeList[] = {
   { "character", "Disable LINEMODE option",   docharmode, 1, 0 },
#ifdef  KLUDGELINEMODE
   { "",       "(or disable obsolete line-by-line mode)", 0, 0, 0 },
#endif
   { "line",   "Enable LINEMODE option",       dolinemode, 1, 0 },
#ifdef  KLUDGELINEMODE
   { "",       "(or enable obsolete line-by-line mode)", 0, 0, 0 },
#endif
   { "", "", 0, 0, 0 },
   { "",       "These require the LINEMODE option to be enabled", 0, 0, 0 },
   { "isig",   "Enable signal trapping",       set_mode, 1, MODE_TRAPSIG },
   { "+isig",  0,                              set_mode, 1, MODE_TRAPSIG },
   { "-isig",  "Disable signal trapping",      clear_mode, 1, MODE_TRAPSIG },
   { "edit",   "Enable character editing",     set_mode, 1, MODE_EDIT },
   { "+edit",  0,                              set_mode, 1, MODE_EDIT },
   { "-edit",  "Disable character editing",    clear_mode, 1, MODE_EDIT },
   { "softtabs", "Enable tab expansion",       set_mode, 1, MODE_SOFT_TAB },
   { "+softtabs", 0,                           set_mode, 1, MODE_SOFT_TAB },
   { "-softtabs", "Disable character editing", clear_mode, 1, MODE_SOFT_TAB },
   { "litecho", "Enable literal character echo", set_mode, 1, MODE_LIT_ECHO },
   { "+litecho", 0,                            set_mode, 1, MODE_LIT_ECHO },
   { "-litecho", "Disable literal character echo", clear_mode, 1, MODE_LIT_ECHO },
   { "help",   0,                              modehelp, 0, 0 },
#ifdef  KLUDGELINEMODE
   { "kludgeline", 0,                          dokludgemode, 1, 0 },
#endif
   { "", "", 0, 0, 0 },
   { "?",      "Print help information",       modehelp, 0, 0 },
   { .name = 0 },
};


int
modehelp(int n)
{
   struct modelist *mt;

   printf("format is:  'mode Mode', where 'Mode' is one of:\n\n");
   for (mt = ModeList; mt->name; mt++) {
       if (mt->help) {
           if (*mt->help)
               printf("%-15s %s\n", mt->name, mt->help);
           else
               printf("\n");
       }
   }
   return 0;
}

#define GETMODECMD(name) (struct modelist *) \
               genget(name, (char **) ModeList, sizeof(struct modelist))

static int
modecmd(int  argc, char *argv[])
{
   struct modelist *mt;

   if (argc != 2) {
       printf("'mode' command requires an argument\n");
       printf("'mode ?' for help.\n");
   } else if ((mt = GETMODECMD(argv[1])) == 0) {
       fprintf(stderr, "Unknown mode '%s' ('mode ?' for help).\n", argv[1]);
   } else if (Ambiguous(mt)) {
       fprintf(stderr, "Ambiguous mode '%s' ('mode ?' for help).\n", argv[1]);
   } else if (mt->needconnect && !connected) {
       printf("?Need to be connected first.\n");
       printf("'mode ?' for help.\n");
   } else if (mt->handler) {
       return (*mt->handler)(mt->arg1);
   }
   return 0;
}

/*
* The following data structures and routines implement the
* "display" command.
*/

static int
display(int  argc, char *argv[])
{
   struct togglelist *tl;
   struct setlist *sl;

#define dotog(tl)       if (tl->variable && tl->actionexplanation) { \
                           if (*tl->variable) { \
                               printf("will"); \
                           } else { \
                               printf("won't"); \
                           } \
                           printf(" %s.\n", tl->actionexplanation); \
                       }

#define doset(sl)   if (sl->name && *sl->name != ' ') { \
                       if (sl->handler == 0) \
                           printf("%-15s [%s]\n", sl->name, control(*sl->charp)); \
                       else \
                           printf("%-15s \"%s\"\n", sl->name, sl->charp); \
                   }

   if (argc == 1) {
       for (tl = Togglelist; tl->name; tl++) {
           dotog(tl);
       }
       printf("\n");
       for (sl = Setlist; sl->name; sl++) {
           doset(sl);
       }
   } else {
       int i;

       for (i = 1; i < argc; i++) {
           sl = getset(argv[i]);
           tl = GETTOGGLE(argv[i]);
           if (Ambiguous(sl) || Ambiguous(tl)) {
               printf("?Ambiguous argument '%s'.\n", argv[i]);
               return 0;
           } else if (!sl && !tl) {
               printf("?Unknown argument '%s'.\n", argv[i]);
               return 0;
           } else {
               if (tl) {
                   dotog(tl);
               }
               if (sl) {
                   doset(sl);
               }
           }
       }
   }
/*@*/optionstatus();
#ifdef  ENCRYPTION
   EncryptStatus(NULL, NULL);
#endif  /* ENCRYPTION */
   return 1;
#undef  doset
#undef  dotog
}

/*
* The following are the data structures, and many of the routines,
* relating to command processing.
*/

/*
* Set the escape character.
*/
static int
setescape(int argc, char *argv[])
{
       char *arg;
       char buf[50];

       printf(
           "Deprecated usage - please use 'set escape%s%s' in the future.\n",
                               (argc > 2)? " ":"", (argc > 2)? argv[1]: "");
       if (argc > 2)
               arg = argv[1];
       else {
               printf("new escape character: ");
               (void) fgets(buf, sizeof(buf), stdin);
               arg = buf;
       }
       if (arg[0] != '\0')
               escape = (cc_t)arg[0];

       printf("Escape character is '%s'.\n", control(escape));
       (void) fflush(stdout);
       return 1;
}

/*VARARGS*/
static int
togcrmod(int argc, char *argv[])
{
   crmod = !crmod;
   printf("Deprecated usage - please use 'toggle crmod' in the future.\n");
   printf("%s map carriage return on output.\n", crmod ? "Will" : "Won't");
   (void) fflush(stdout);
   return 1;
}

/*VARARGS*/
int
suspend(int argc, char *argv[])
{
   setcommandmode();
   {
       long oldrows, oldcols, newrows, newcols, err;

       err = (TerminalWindowSize(&oldrows, &oldcols) == 0) ? 1 : 0;
       (void) kill(0, SIGTSTP);
       /*
        * If we didn't get the window size before the SUSPEND, but we
        * can get them now (?), then send the NAWS to make sure that
        * we are set up for the right window size.
        */
       if (TerminalWindowSize(&newrows, &newcols) && connected &&
           (err || ((oldrows != newrows) || (oldcols != newcols)))) {
               sendnaws();
       }
   }
   /* reget parameters in case they were changed */
   TerminalSaveState();
   setconnmode(0);
   return 1;
}

/*ARGSUSED*/
int
shell(int argc, char *argv[])
{
   long oldrows, oldcols, newrows, newcols;
   long volatile err;  /* Avoid vfork clobbering */

   setcommandmode();

   err = (TerminalWindowSize(&oldrows, &oldcols) == 0) ? 1 : 0;
   switch(vfork()) {
   case -1:
       warn("Fork failed");
       break;

   case 0:
       {
           /*
            * Fire up the shell in the child.
            */
           const char *shellp, *shellname;

           shellp = getenv("SHELL");
           if (shellp == NULL)
               shellp = "/bin/sh";
           if ((shellname = strrchr(shellp, '/')) == 0)
               shellname = shellp;
           else
               shellname++;
           if (argc > 1)
               execl(shellp, shellname, "-c", &saveline[1], NULL);
           else
               execl(shellp, shellname, NULL);
           warn("execl");
           _exit(1);
       }
   default:
           (void)wait((int *)0);       /* Wait for the shell to complete */

           if (TerminalWindowSize(&newrows, &newcols) && connected &&
               (err || ((oldrows != newrows) || (oldcols != newcols)))) {
                   sendnaws();
           }
           break;
   }
   return 1;
}

/*VARARGS*/
static int
bye(int  argc, char *argv[])
{
   extern int resettermname;

   if (connected) {
       (void) shutdown(net, 2);
       printf("Connection closed.\n");
       (void) NetClose(net);
       connected = 0;
       resettermname = 1;
#if     defined(AUTHENTICATION) || defined(ENCRYPTION)
       auth_encrypt_connect(connected);
#endif  /* defined(AUTHENTICATION) */
       /* reset options */
       tninit();
   }
   if ((argc != 2) || (strcmp(argv[1], "fromquit") != 0)) {
       longjmp(toplevel, 1);
       /* NOTREACHED */
   }
   return 1;                   /* Keep lint, etc., happy */
}

/*VARARGS*/
int
quit(int argc, char *argv[])
{
       (void) call(bye, "bye", "fromquit", 0);
       Exit(0);
       /*NOTREACHED*/
}

/*VARARGS*/
int
logout(int argc, char *argv[])
{
       send_do(TELOPT_LOGOUT, 1);
       (void) netflush();
       return 1;
}


/*
* The SLC command.
*/

struct slclist {
       const char      *name;
       const char      *help;
       void    (*handler)(int);
       int     arg;
};

struct slclist SlcList[] = {
   { "export", "Use local special character definitions",
                                               slc_mode_export,        0 },
   { "import", "Use remote special character definitions",
                                               slc_mode_import,        1 },
   { "check",  "Verify remote special character definitions",
                                               slc_mode_import,        0 },
   { "help",   0,                              slc_help,               0 },
   { "?",      "Print help information",       slc_help,               0 },
   { .name = 0 },
};

static void
slc_help(int n)
{
   struct slclist *c;

   for (c = SlcList; c->name; c++) {
       if (c->help) {
           if (*c->help)
               printf("%-15s %s\n", c->name, c->help);
           else
               printf("\n");
       }
   }
}

static struct slclist *
getslc(const char *name)
{
   return (struct slclist *)
               genget(name, (char **) SlcList, sizeof(struct slclist));
}

static int
slccmd(int  argc, char *argv[])
{
   struct slclist *c;

   if (argc != 2) {
       fprintf(stderr,
           "Need an argument to 'slc' command.  'slc ?' for help.\n");
       return 0;
   }
   c = getslc(argv[1]);
   if (c == 0) {
       fprintf(stderr, "'%s': unknown argument ('slc ?' for help).\n",
                               argv[1]);
       return 0;
   }
   if (Ambiguous(c)) {
       fprintf(stderr, "'%s': ambiguous argument ('slc ?' for help).\n",
                               argv[1]);
       return 0;
   }
   (*c->handler)(c->arg);
   slcstate();
   return 1;
}

/*
* The ENVIRON command.
*/

struct envlist {
       const char      *name;
       const char      *help;
       struct env_lst *(*handler)(const char *, char *);
       int     narg;
};

struct envlist EnvList[] = {
   { "define", "Define an environment variable",
                                               env_define,     2 },
   { "undefine", "Undefine an environment variable",
                                               env_undefine,   1 },
   { "export", "Mark an environment variable for automatic export",
                                               env_export,     1 },
   { "unexport", "Don't mark an environment variable for automatic export",
                                               env_unexport,   1 },
   { "send",   "Send an environment variable", env_send,       1 },
   { "list",   "List the current environment variables",
                                               env_list,       0 },
   { "help",   0,                              env_help,               0 },
   { "?",      "Print help information",       env_help,               0 },
   { .name = 0 },
};

static struct env_lst *
env_help(const char *us1, char *us2)
{
   struct envlist *c;

   for (c = EnvList; c->name; c++) {
       if (c->help) {
           if (*c->help)
               printf("%-15s %s\n", c->name, c->help);
           else
               printf("\n");
       }
   }
   return NULL;
}

static struct envlist *
getenvcmd(const char *name)
{
   return (struct envlist *)
               genget(name, (char **) EnvList, sizeof(struct envlist));
}

int
env_cmd(int  argc, char *argv[])
{
   struct envlist *c;

   if (argc < 2) {
       fprintf(stderr,
           "Need an argument to 'environ' command.  'environ ?' for help.\n");
       return 0;
   }
   c = getenvcmd(argv[1]);
   if (c == 0) {
       fprintf(stderr, "'%s': unknown argument ('environ ?' for help).\n",
                               argv[1]);
       return 0;
   }
   if (Ambiguous(c)) {
       fprintf(stderr, "'%s': ambiguous argument ('environ ?' for help).\n",
                               argv[1]);
       return 0;
   }
   if (c->narg + 2 != argc) {
       fprintf(stderr,
           "Need %s%d argument%s to 'environ %s' command.  'environ ?' for help.\n",
               c->narg < argc + 2 ? "only " : "",
               c->narg, c->narg == 1 ? "" : "s", c->name);
       return 0;
   }
   (*c->handler)(argv[2], argv[3]);
   return 1;
}

struct env_lst {
       struct env_lst *next;   /* pointer to next structure */
       struct env_lst *prev;   /* pointer to previous structure */
       unsigned char *var;     /* pointer to variable name */
       unsigned char *value;   /* pointer to variable value */
       int export;             /* 1 -> export with default list of variables */
       int welldefined;        /* A well defined variable */
};

struct env_lst envlisthead;

struct env_lst *
env_find(const char *var)
{
       struct env_lst *ep;

       for (ep = envlisthead.next; ep; ep = ep->next) {
               if (strcmp(ep->var, var) == 0)
                       return ep;
       }
       return NULL;
}

void
env_init(void)
{
       extern char **environ;
       char **epp, *cp;
       struct env_lst *ep;

       for (epp = environ; *epp; epp++) {
               if ((cp = strchr(*epp, '=')) != NULL) {
                       *cp = '\0';
                       ep = env_define((unsigned char *)*epp,
                                       (unsigned char *)cp+1);
                       ep->export = 0;
                       *cp = '=';
               }
       }
       /*
        * Special case for DISPLAY variable.  If it is ":0.0" or
        * "unix:0.0", we have to get rid of "unix" and insert our
        * hostname.
        */
       if ((ep = env_find("DISPLAY"))
           && ((*ep->value == ':')
               || (strncmp(ep->value, "unix:", 5) == 0))) {
               char hbuf[MAXHOSTNAMELEN + 1];
               char *cp2 = strchr(ep->value, ':');

               gethostname(hbuf, sizeof hbuf);
               hbuf[sizeof(hbuf) - 1] = '\0';
               if (asprintf(&cp, "%s%s", hbuf, cp2) < 0)
                       err(1, "Out of memory");
               free(ep->value);
               ep->value = cp;
       }
       /*
        * If USER is not defined, but LOGNAME is, then add
        * USER with the value from LOGNAME.  By default, we
        * don't export the USER variable.
        */
       if ((env_find("USER") == NULL) && (ep = env_find("LOGNAME"))) {
               env_define("USER", ep->value);
               env_unexport("USER", NULL);
       }
       env_export("DISPLAY", NULL);
       env_export("PRINTER", NULL);
}

struct env_lst *
env_define(const char *var, char *value)
{
       struct env_lst *ep;

       if ((ep = env_find(var)) != NULL) {
               if (ep->var)
                       free(ep->var);
               if (ep->value)
                       free(ep->value);
       } else {
               ep = (struct env_lst *)malloc(sizeof(struct env_lst));
               ep->next = envlisthead.next;
               envlisthead.next = ep;
               ep->prev = &envlisthead;
               if (ep->next)
                       ep->next->prev = ep;
       }
       ep->welldefined = opt_welldefined(var);
       ep->export = 1;
       ep->var = strdup(var);
       ep->value = strdup(value);
       return ep;
}

struct env_lst *
env_undefine(const char *var, char *d)
{
       struct env_lst *ep;

       if ((ep = env_find(var)) != NULL) {
               ep->prev->next = ep->next;
               if (ep->next)
                       ep->next->prev = ep->prev;
               if (ep->var)
                       free(ep->var);
               if (ep->value)
                       free(ep->value);
               free(ep);
       }
       return NULL;
}

struct env_lst *
env_export(const char *var, char *d)
{
       struct env_lst *ep;

       if ((ep = env_find(var)) != NULL)
               ep->export = 1;
       return NULL;
}

struct env_lst *
env_unexport(const char *var, char *d)
{
       struct env_lst *ep;

       if ((ep = env_find(var)) != NULL)
               ep->export = 0;
       return NULL;
}

struct env_lst *
env_send(const char *var, char *d)
{
       struct env_lst *ep;

       if (my_state_is_wont(TELOPT_NEW_ENVIRON)
               ) {
               fprintf(stderr,
                   "Cannot send '%s': Telnet ENVIRON option not enabled\n",
                                                                       var);
               return NULL;
       }
       ep = env_find(var);
       if (ep == 0) {
               fprintf(stderr, "Cannot send '%s': variable not defined\n",
                                                                       var);
               return NULL;
       }
       env_opt_start_info();
       env_opt_add(ep->var);
       env_opt_end(0);
       return NULL;
}

struct env_lst *
env_list(const char *d1, char *d2)
{
       struct env_lst *ep;

       for (ep = envlisthead.next; ep; ep = ep->next) {
               printf("%c %-20s %s\n", ep->export ? '*' : ' ',
                                       ep->var, ep->value);
       }
       return NULL;
}

char *
env_default(int init, int welldefined)
{
       static struct env_lst *nep = NULL;

       if (init) {
               nep = &envlisthead;
               return NULL;
       }
       if (!nep) {
               return NULL;
       }
       while ((nep = nep->next) != NULL) {
               if (nep->export && (nep->welldefined == welldefined))
                       return nep->var;
       }
       return NULL;
}

char *
env_getvalue(const char *var)
{
       struct env_lst *ep;

       if ((ep = env_find(var)) != NULL)
               return ep->value;
       return NULL;
}

#ifdef AUTHENTICATION
/*
* The AUTHENTICATE command.
*/

struct authlist {
       const char      *name;
       const char      *help;
       int     (*handler)(const char *);
       int     narg;
};

struct authlist AuthList[] = {
   { "status", "Display current status of authentication information",
                                               auth_status,    0 },
   { "disable", "Disable an authentication type ('auth disable ?' for more)",
                                               auth_disable,   1 },
   { "enable", "Enable an authentication type ('auth enable ?' for more)",
                                               auth_enable,    1 },
   { "help",   0,                              auth_help,              0 },
   { "?",      "Print help information",       auth_help,              0 },
   { .name = 0 },
};

static int
auth_help(const char *s)
{
   struct authlist *c;

   for (c = AuthList; c->name; c++) {
       if (c->help) {
           if (*c->help)
               printf("%-15s %s\n", c->name, c->help);
           else
               printf("\n");
       }
   }
   return 0;
}

int
auth_cmd(int  argc, char *argv[])
{
   struct authlist *c;

   if (argc < 2) {
       fprintf(stderr,
           "Need an argument to 'auth' command.  'auth ?' for help.\n");
       return 0;
   }

   c = (struct authlist *)
               genget(argv[1], (char **) AuthList, sizeof(struct authlist));
   if (c == 0) {
       fprintf(stderr, "'%s': unknown argument ('auth ?' for help).\n",
                               argv[1]);
       return 0;
   }
   if (Ambiguous(c)) {
       fprintf(stderr, "'%s': ambiguous argument ('auth ?' for help).\n",
                               argv[1]);
       return 0;
   }
   if (c->narg + 2 != argc) {
       fprintf(stderr,
           "Need %s%d argument%s to 'auth %s' command.  'auth ?' for help.\n",
               c->narg < argc + 2 ? "only " : "",
               c->narg, c->narg == 1 ? "" : "s", c->name);
       return 0;
   }
   return (*c->handler)(argv[2]);
}
#endif

#ifdef  ENCRYPTION
/*
* The ENCRYPT command.
*/

struct encryptlist {
       const char      *name;
       const char      *help;
       int     (*handler)(char *, char *);
       int     needconnect;
       int     minarg;
       int     maxarg;
};

static int EncryptHelp(char *, char *);

struct encryptlist EncryptList[] = {
   { "enable", "Enable encryption. ('encrypt enable ?' for more)",
                                               EncryptEnable, 1, 1, 2 },
   { "disable", "Disable encryption. ('encrypt enable ?' for more)",
                                               EncryptDisable, 0, 1, 2 },
   { "type", "Set encryption type. ('encrypt type ?' for more)",
                                               EncryptType, 0, 1, 1 },
   { "start", "Start encryption. ('encrypt start ?' for more)",
                                               EncryptStart, 1, 0, 1 },
   { "stop", "Stop encryption. ('encrypt stop ?' for more)",
                                               EncryptStop, 1, 0, 1 },
   { "input", "Start encrypting the input stream",
                                               EncryptStartInput, 1, 0, 0 },
   { "-input", "Stop encrypting the input stream",
                                               EncryptStopInput, 1, 0, 0 },
   { "output", "Start encrypting the output stream",
                                               EncryptStartOutput, 1, 0, 0 },
   { "-output", "Stop encrypting the output stream",
                                               EncryptStopOutput, 1, 0, 0 },

   { "status",       "Display current status of authentication information",
                                               EncryptStatus,  0, 0, 0 },
   { "help", 0,                                EncryptHelp,    0, 0, 0 },
   { "?",    "Print help information",         EncryptHelp,    0, 0, 0 },
   { .name = 0 },
};

static int
EncryptHelp(char *s1, char *s2)
{
       struct encryptlist *c;

       for (c = EncryptList; c->name; c++) {
               if (c->help) {
                       if (*c->help)
                               printf("%-15s %s\n", c->name, c->help);
                       else
                               printf("\n");
               }
       }
       return (0);
}

int
encrypt_cmd(int argc, char *argv[])
{
       struct encryptlist *c;

       if (argc < 2) {
               fprintf(stderr,
                   "Need an argument to 'encrypt' command.  "
                   "'encrypt ?' for help.\n");
               return (0);
       }

       c = (struct encryptlist *)
           genget(argv[1], (char **) EncryptList, sizeof(struct encryptlist));
       if (c == NULL) {
               fprintf(stderr,
                   "'%s': unknown argument ('encrypt ?' for help).\n",
                   argv[1]);
               return (0);
       }
       if (Ambiguous(c)) {
               fprintf(stderr,
                   "'%s': ambiguous argument ('encrypt ?' for help).\n",
                   argv[1]);
               return (0);
       }
       argc -= 2;
       if (argc < c->minarg || argc > c->maxarg) {
               if (c->minarg == c->maxarg) {
                       fprintf(stderr, "Need %s%d argument%s ",
                           c->minarg < argc ? "only " : "", c->minarg,
                           c->minarg == 1 ? "" : "s");
               } else {
                       fprintf(stderr, "Need %s%d-%d arguments ",
                           c->maxarg < argc ? "only " : "", c->minarg,
                           c->maxarg);
               }
               fprintf(stderr,
                   "to 'encrypt %s' command.  'encrypt ?' for help.\n",
                   c->name);
               return (0);
       }
       if (c->needconnect && !connected) {
               if (!(argc && (isprefix(argv[2], "help") ||
                   isprefix(argv[2], "?")))) {
                       printf("?Need to be connected first.\n");
                       return (0);
               }
       }
       return ((*c->handler)(argv[2], argv[3]));
}
#endif  /* ENCRYPTION */


/*
* Print status about the connection.
*/
/*ARGSUSED*/
static int
status(int argc, char *argv[])
{
   if (connected) {
       printf("Connected to %s.\n", hostname);
       if ((argc < 2) || strcmp(argv[1], "notmuch")) {
           int mode = getconnmode();

           if (my_want_state_is_will(TELOPT_LINEMODE)) {
               printf("Operating with LINEMODE option\n");
               printf("%s line editing\n", (mode&MODE_EDIT) ? "Local" : "No");
               printf("%s catching of signals\n",
                                       (mode&MODE_TRAPSIG) ? "Local" : "No");
               slcstate();
#ifdef  KLUDGELINEMODE
           } else if (kludgelinemode && my_want_state_is_dont(TELOPT_SGA)) {
               printf("Operating in obsolete linemode\n");
#endif
           } else {
               printf("Operating in single character mode\n");
               if (localchars)
                   printf("Catching signals locally\n");
           }
           printf("%s character echo\n", (mode&MODE_ECHO) ? "Local" : "Remote");
           if (my_want_state_is_will(TELOPT_LFLOW))
               printf("%s flow control\n", (mode&MODE_FLOW) ? "Local" : "No");
#ifdef  ENCRYPTION
           encrypt_display();
#endif  /* ENCRYPTION */
       }
   } else {
       printf("No connection.\n");
   }
   printf("Escape character is '%s'.\n", control(escape));
   (void) fflush(stdout);
   return 1;
}

/*
* Function that gets called when SIGINFO is received.
*/
int
ayt_status(void)
{
   return call(status, "status", "notmuch", 0);
}

static const char *
sockaddr_ntop(struct sockaddr *sa)
{
   static char addrbuf[NI_MAXHOST];
   const int niflags = NI_NUMERICHOST;

   if (getnameinfo(sa, sa->sa_len, addrbuf, sizeof(addrbuf),
           NULL, 0, niflags) == 0)
       return addrbuf;
   else
       return NULL;
}

#if defined(IPSEC) && defined(IPSEC_POLICY_IPSEC)
static int setpolicy (int, struct addrinfo *, char *);

static int
setpolicy(int netw, struct addrinfo *res, char *policy)
{
       char *buf;
       int level;
       int optname;

       if (policy == NULL)
               return 0;

       buf = ipsec_set_policy(policy, (int)strlen(policy));
       if (buf == NULL) {
               printf("%s\n", ipsec_strerror());
               return -1;
       }
       level = res->ai_family == AF_INET ? IPPROTO_IP : IPPROTO_IPV6;
       optname = res->ai_family == AF_INET ? IP_IPSEC_POLICY : IPV6_IPSEC_POLICY;
       if (setsockopt(netw, level, optname, buf, (socklen_t)ipsec_get_policylen(buf)) < 0){
               warn("setsockopt");
               return -1;
       }

       free(buf);
       return 0;
}
#endif

int
tn(int argc, char *argv[])
{
   struct addrinfo hints, *res, *res0;
   const char *cause = "telnet: unknown";
   int error, serrno = 0;
   char *cmd, *hostp = 0;
   const char *portp = 0;
   const char *user = 0;

   if (connected) {
       printf("?Already connected to %s\n", hostname);
       return 0;
   }
   if (argc < 2) {
       (void) strlcpy(line, "open ", sizeof(line));
       printf("(to) ");
       (void) fgets(&line[strlen(line)], (int)(sizeof(line) - strlen(line)),
           stdin);
       makeargv();
       argc = margc;
       argv = margv;
   }
   cmd = *argv;
   --argc; ++argv;
   while (argc) {
       if (strcmp(*argv, "help") == 0 || isprefix(*argv, "?"))
           goto usage;
       if (strcmp(*argv, "-l") == 0) {
           --argc; ++argv;
           if (argc == 0)
               goto usage;
           user = *argv++;
           --argc;
           continue;
       }
       if (strcmp(*argv, "-a") == 0) {
           --argc; ++argv;
           autologin = 1;
           continue;
       }
       if (hostp == 0) {
           hostp = *argv++;
           --argc;
           continue;
       }
       if (portp == 0) {
           portp = *argv++;
           --argc;
           continue;
       }
   usage:
       printf("usage: %s [-l user] [-a] host-name [port]\n", cmd);
       return 0;
   }
   if (hostp == 0)
       goto usage;

   (void) strlcpy(_hostname, hostp, sizeof(_hostname));
   hostname = hostp;

   if (!portp) {
       telnetport = 1;
       portp = "telnet";
   } else if (portp[0] == '-') {
       /* use telnet negotiation if port number/name preceded by minus sign */
       telnetport = 1;
       portp++;
   } else
       telnetport = 0;

   memset(&hints, 0, sizeof(hints));
   hints.ai_family = family;
   hints.ai_socktype = SOCK_STREAM;
   hints.ai_protocol = 0;
   hints.ai_flags = AI_NUMERICHOST;    /* avoid forward lookup */
   error = getaddrinfo(hostname, portp, &hints, &res0);
   if (!error) {
       /* numeric */
       if (doaddrlookup &&
           getnameinfo(res0->ai_addr, res0->ai_addrlen,
               _hostname, sizeof(_hostname), NULL, 0, NI_NAMEREQD) == 0)
           ; /* okay */
       else
           strlcpy(_hostname, hostname, sizeof(_hostname));
   } else {
       /* FQDN - try again with forward DNS lookup */
       memset(&hints, 0, sizeof(hints));
       hints.ai_family = family;
       hints.ai_socktype = SOCK_STREAM;
       hints.ai_protocol = 0;
       hints.ai_flags = AI_CANONNAME;
       error = getaddrinfo(hostname, portp, &hints, &res0);
       if (error == EAI_SERVICE) {
           fprintf(stderr, "tcp/%s: unknown service\n", portp);
           return 0;
       } else if (error) {
           fprintf(stderr, "%s: %s\n", hostname, gai_strerror(error));
           return 0;
       }
       if (res0->ai_canonname)
           (void)strlcpy(_hostname, res0->ai_canonname, sizeof(_hostname));
       else
           (void)strlcpy(_hostname, hostname, sizeof(_hostname));
   }
   hostname = _hostname;

   net = -1;
   for (res = res0; res; res = res->ai_next) {
       printf("Trying %s...\n", sockaddr_ntop(res->ai_addr));
       net = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
       if (net < 0) {
           serrno = errno;
           cause = "telnet: socket";
           continue;
       }

       if (telnet_debug && SetSockOpt(net, SOL_SOCKET, SO_DEBUG, 1) < 0) {
           warn("setsockopt (SO_DEBUG)");
       }

#if defined(IPSEC) && defined(IPSEC_POLICY_IPSEC)
       if (setpolicy(net, res, ipsec_policy_in) < 0) {
           serrno = errno;
           (void) NetClose(net);
           net = -1;
           continue;
       }
       if (setpolicy(net, res, ipsec_policy_out) < 0) {
           serrno = errno;
           (void) NetClose(net);
           net = -1;
           continue;
       }
#endif

       if (connect(net, res->ai_addr, res->ai_addrlen) < 0) {
           if (res->ai_next) {
               warn("Connect to address %s: ", sockaddr_ntop(res->ai_addr));
           }
           serrno = errno;
           cause = "Unable to connect to remote host";
           (void) NetClose(net);
           net = -1;
           continue;
       }

       connected++;
#if     defined(AUTHENTICATION) || defined(ENCRYPTION)
       auth_encrypt_connect(connected);
#endif  /* defined(AUTHENTICATION) || defined(ENCRYPTION) */
       break;
   }
   freeaddrinfo(res0);
   if (net < 0 || connected == 0) {
       warnc(serrno, "%s", cause);
       return 0;
   }

   cmdrc(hostp, hostname);
   if (autologin && user == NULL) {
       struct passwd *pw;

       user = getenv("USER");
       if (user == NULL ||
           ((pw = getpwnam(user)) && pw->pw_uid != getuid())) {
               if ((pw = getpwuid(getuid())) != NULL)
                       user = pw->pw_name;
               else
                       user = NULL;
       }
   }
   if (user) {
       env_define("USER", __UNCONST(user));
       env_export("USER", NULL);
   }
   (void) call(status, "status", "notmuch", 0);
   telnet(user);
   (void) NetClose(net);
   ExitString("Connection closed by foreign host.\n",1);
   /*NOTREACHED*/
}

#define HELPINDENT ((int)sizeof ("connect"))

static char
       openhelp[] =    "connect to a site",
       closehelp[] =   "close current connection",
       logouthelp[] =  "forcibly logout remote user and close the connection",
       quithelp[] =    "exit telnet",
       statushelp[] =  "print status information",
       helphelp[] =    "print help information",
       sendhelp[] =    "transmit special characters ('send ?' for more)",
       sethelp[] =     "set operating parameters ('set ?' for more)",
       unsethelp[] =   "unset operating parameters ('unset ?' for more)",
       togglestring[] ="toggle operating parameters ('toggle ?' for more)",
       slchelp[] =     "change state of special characters ('slc ?' for more)",
       displayhelp[] = "display operating parameters",
#ifdef AUTHENTICATION
       authhelp[] =    "turn on (off) authentication ('auth ?' for more)",
#endif
#ifdef  ENCRYPTION
       encrypthelp[] = "turn on (off) encryption ('encrypt ?' for more)",
#endif  /* ENCRYPTION */
       zhelp[] =       "suspend telnet",
       shellhelp[] =   "invoke a subshell",
       envhelp[] =     "change environment variables ('environ ?' for more)",
       modestring[] = "try to enter line or character mode ('mode ?' for more)";

static Command cmdtab[] = {
       { "close",      closehelp,      bye,            1 },
       { "logout",     logouthelp,     logout,         1 },
       { "display",    displayhelp,    display,        0 },
       { "mode",       modestring,     modecmd,        0 },
       { "open",       openhelp,       tn,             0 },
       { "quit",       quithelp,       quit,           0 },
       { "send",       sendhelp,       sendcmd,        0 },
       { "set",        sethelp,        setcmd,         0 },
       { "unset",      unsethelp,      unsetcmd,       0 },
       { "status",     statushelp,     status,         0 },
       { "toggle",     togglestring,   toggle,         0 },
       { "slc",        slchelp,        slccmd,         0 },
#ifdef AUTHENTICATION
       { "auth",       authhelp,       auth_cmd,       0 },
#endif
#ifdef  ENCRYPTION
       { "encrypt",    encrypthelp,    encrypt_cmd,    0 },
#endif
       { "z",          zhelp,          suspend,        0 },
       { "!",          shellhelp,      shell,          0 },
       { "environ",    envhelp,        env_cmd,        0 },
       { "?",          helphelp,       help,           0 },
       { NULL,         NULL,           NULL,           0 }
};

static char     crmodhelp[] =   "deprecated command -- use 'toggle crmod' instead";
static char     escapehelp[] =  "deprecated command -- use 'set escape' instead";

static Command cmdtab2[] = {
       { "help",       0,              help,           0 },
       { "escape",     escapehelp,     setescape,      0 },
       { "crmod",      crmodhelp,      togcrmod,       0 },
       { NULL,         NULL,           NULL,           0 }
};


/*
* Call routine with argc, argv set from args (terminated by 0).
*/

/*VARARGS1*/
static int
call(intrtn_t routine, ...)
{
   va_list ap;
   char *args[100];
   int argno = 0;

   va_start(ap, routine);
   while ((args[argno++] = va_arg(ap, char *)) != 0) {
       ;
   }
   va_end(ap);
   return (*routine)(argno-1, args);
}


static Command *
getcmd(const char *name)
{
   Command *cm;

   if ((cm = (Command *) genget(name, (char **) cmdtab, sizeof(Command))) != NULL)
       return cm;
   return (Command *) genget(name, (char **) cmdtab2, sizeof(Command));
}

void
command(int top, const char *tbuf, int cnt)
{
   Command *c;

   setcommandmode();
   if (!top) {
       putchar('\n');
   } else {
       (void) signal(SIGINT, SIG_DFL);
       (void) signal(SIGQUIT, SIG_DFL);
   }
   for (;;) {
       if (rlogin == _POSIX_VDISABLE)
               printf("%s> ", prompt);
       if (tbuf) {
           char *cp;
           cp = line;
           while (cnt > 0 && (*cp++ = *tbuf++) != '\n')
               cnt--;
           tbuf = 0;
           if (cp == line || *--cp != '\n' || cp == line)
               goto getline;
           *cp = '\0';
           if (rlogin == _POSIX_VDISABLE)
               printf("%s\n", line);
       } else {
       getline:
           if (rlogin != _POSIX_VDISABLE)
               printf("%s> ", prompt);
           if (fgets(line, sizeof(line), stdin) == NULL) {
               if (feof(stdin) || ferror(stdin)) {
                   (void) quit(0, NULL);
                   /*NOTREACHED*/
               }
               break;
           }
       }
       if (line[0] == 0)
           break;
       makeargv();
       if (margv[0] == 0) {
           break;
       }
       c = getcmd(margv[0]);
       if (Ambiguous(c)) {
           printf("?Ambiguous command\n");
           continue;
       }
       if (c == 0) {
           printf("?Invalid command\n");
           continue;
       }
       if (c->needconnect && !connected) {
           printf("?Need to be connected first.\n");
           continue;
       }
       if ((*c->handler)(margc, margv)) {
           break;
       }
   }
   if (!top) {
       if (!connected) {
           longjmp(toplevel, 1);
           /*NOTREACHED*/
       }
       setconnmode(0);
   }
}

/*
* Help command.
*/
static int
help(int argc, char *argv[])
{
       Command *c;

       if (argc == 1) {
               printf("Commands may be abbreviated.  Commands are:\n\n");
               for (c = cmdtab; c->name; c++)
                       if (c->help) {
                               printf("%-*s\t%s\n", HELPINDENT, c->name,
                                                                   c->help);
                       }
               return 0;
       }
       while (--argc > 0) {
               char *arg;
               arg = *++argv;
               c = getcmd(arg);
               if (Ambiguous(c))
                       printf("?Ambiguous help command %s\n", arg);
               else if (c == (Command *)0)
                       printf("?Invalid help command %s\n", arg);
               else if (c->help)
                       printf("%s\n", c->help);
       }
       return 0;
}

static char *rcname = 0;
static char rcbuf[128];

void
cmdrc(const char *m1, const char *m2)
{
   Command *c;
   FILE *rcfile;
   int gotmachine = 0;
   size_t l1 = strlen(m1);
   size_t l2 = strlen(m2);
   char m1save[MAXHOSTNAMELEN + 1];

   if (skiprc)
       return;

   strlcpy(m1save, m1, sizeof(m1save));
   m1 = m1save;

   if (rcname == 0) {
       rcname = getenv("HOME");
       if (rcname)
           strlcpy(rcbuf, rcname, sizeof(rcbuf));
       else
           rcbuf[0] = '\0';
       strlcat(rcbuf, "/.telnetrc", sizeof(rcbuf));
       rcname = rcbuf;
   }

   if ((rcfile = fopen(rcname, "r")) == 0) {
       return;
   }

   for (;;) {
       if (fgets(line, sizeof(line), rcfile) == NULL)
           break;
       if (line[0] == 0)
           break;
       if (line[0] == '#')
           continue;
       if (gotmachine) {
           if (!isspace((unsigned char)line[0]))
               gotmachine = 0;
       }
       if (gotmachine == 0) {
           if (isspace((unsigned char)line[0]))
               continue;
           if (strncasecmp(line, m1, l1) == 0)
               memmove(line, &line[l1], sizeof(line) - l1 - 1);
           else if (strncasecmp(line, m2, l2) == 0)
               memmove(line, &line[l2], sizeof(line) - l2 - 1);
           else if (strncasecmp(line, "DEFAULT", 7) == 0)
               memmove(line, &line[7], sizeof(line) - 7 - 1);
           else
               continue;
           line[sizeof(line) - 1] = '\0';
           if (line[0] != ' ' && line[0] != '\t' && line[0] != '\n')
               continue;
           gotmachine = 1;
       }
       makeargv();
       if (margv[0] == 0)
           continue;
       c = getcmd(margv[0]);
       if (Ambiguous(c)) {
           printf("?Ambiguous command: %s\n", margv[0]);
           continue;
       }
       if (c == 0) {
           printf("?Invalid command: %s\n", margv[0]);
           continue;
       }
       /*
        * This should never happen...
        */
       if (c->needconnect && !connected) {
           printf("?Need to be connected first for %s.\n", margv[0]);
           continue;
       }
       (*c->handler)(margc, margv);
   }
   fclose(rcfile);
}