/* $OpenBSD: commands.c,v 1.85 2017/07/19 12:25:52 deraadt Exp $ */ /* $NetBSD: commands.c,v 1.14 1996/03/24 22:03:48 jtk Exp $ */ /* * 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 "telnet_locl.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include char *hostname; typedef struct { char *name; /* command name */ char *help; /* help string (NULL for no help) */ int (*handler)(int, char **);/* routine which executes command */ int needconnect; /* Do we need to be connected to execute? */ } Command; static char line[256]; static int margc; static char *margv[20]; static void makeargv(void) { char *cp, *cp2, c; char **argp = margv; margc = 0; cp = line; while ((c = *cp)) { int inquote = 0; while (isspace((unsigned char)c)) c = *++cp; if (c == '\0') break; *argp++ = cp; margc += 1; 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 == '"') { inquote = '"'; continue; } else if (c == '\'') { inquote = '\''; continue; } else if (isspace((unsigned char)c)) break; } *cp2++ = c; } *cp2 = '\0'; if (c == '\0') break; cp++; } *argp++ = 0; } /* * Make a character string into a number. * * Todo: 1. Could take random integers (12, 0x12, 012, 0b1). */ static char special(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 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 { char *name; /* How user refers to it (case independent) */ 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) */ int nbyte; /* Number of bytes to send this command */ int what; /* Character to be sent (<0 ==> special) */ }; static int send_esc(void), send_help(void), send_docmd(char *), send_dontcmd(char *), send_willcmd(char *), send_wontcmd(char *); 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 }, { 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\r\n"); printf("'send ?' for help\r\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'\r\n'send ?' for help.\r\n", argv[i]); return 0; } else if (Ambiguous(s)) { printf("Ambiguous send argument '%s'\r\n'send ?' for help.\r\n", argv[i]); return 0; } if (i + s->narg >= argc) { fprintf(stderr, "Need %d argument%s to 'send %s' command. 'send %s ?' for help.\r\n", s->narg, s->narg == 1 ? "" : "s", s->name, s->name); return 0; } count += s->nbyte; if (s->handler == send_help) { send_help(); return 0; } i += s->narg; needconnect += s->needconnect; } if (!connected && needconnect) { printf("?Need to be connected first.\r\n"); printf("'send ?' for help\r\n"); return 0; } /* Now, do we have enough room? */ if (NETROOM() < count) { printf("There is not enough room in the buffer TO the network\r\n"); printf("to process your request. Nothing will be done.\r\n"); printf("('send synch' will throw away most data in the network\r\n"); printf("buffer, if this might help.)\r\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!\r\n"); quit(); } if (s->handler) { count++; success += (*s->handler)((s->narg > 0) ? argv[i+1] : 0, (s->narg > 1) ? argv[i+2] : 0); i += s->narg; } else { NET2ADD(IAC, s->what); printoption("SENT", IAC, s->what); } } return (count == success); } static int send_tncmd(void (*func)(int, int), char *cmd, char *name); static int send_esc(void) { NETADD(escape); return 1; } static int send_docmd(char *name) { return(send_tncmd(send_do, "do", name)); } static int send_dontcmd(char *name) { return(send_tncmd(send_dont, "dont", name)); } static int send_willcmd(char *name) { return(send_tncmd(send_will, "will", name)); } static int send_wontcmd(char *name) { return(send_tncmd(send_wont, "wont", name)); } int send_tncmd(void (*func)(int, int), char *cmd, char *name) { char **cpp; extern char *telopts[]; int val = 0; if (isprefix(name, "help") || isprefix(name, "?")) { int col, len; printf("Usage: send %s \r\n", cmd); printf("\"value\" must be from 0 to 255\r\n"); printf("Valid options are:\r\n\t"); col = 8; for (cpp = telopts; *cpp; cpp++) { len = strlen(*cpp) + 3; if (col + len > 65) { printf("\r\n\t"); col = 8; } printf(" \"%s\"", *cpp); col += len; } printf("\r\n"); return 0; } cpp = (char **)genget(name, telopts, sizeof(char *)); if (Ambiguous(cpp)) { fprintf(stderr,"'%s': ambiguous argument ('send %s ?' for help).\r\n", name, cmd); return 0; } if (cpp) { val = cpp - telopts; } else { 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).\r\n", name, cmd); return 0; } else if (val < 0 || val > 255) { fprintf(stderr, "'%s': bad value ('send %s ?' for help).\r\n", name, cmd); return 0; } } if (!connected) { printf("?Need to be connected first.\r\n"); return 0; } (*func)(val, 1); return 1; } static int send_help(void) { struct sendlist *s; /* pointer to current command */ for (s = Sendlist; s->name; s++) { if (s->help) printf("%-15s %s\r\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 unused) { donelclchars = 1; return 1; } static int togcrlf(int unused) { if (crlf) { printf("Will send carriage returns as telnet .\r\n"); } else { printf("Will send carriage returns as telnet .\r\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.\r\n"); } else { printf("Negotiating binary mode with remote host.\r\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.\r\n"); } else { printf("Negotiating network ascii mode with remote host.\r\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.\r\n"); } else { printf("Negotiating binary mode on input.\r\n"); tel_enter_binary(1); } } else { if (my_want_state_is_dont(TELOPT_BINARY)) { printf("Already receiving in network ascii mode.\r\n"); } else { printf("Negotiating network ascii mode on input.\r\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.\r\n"); } else { printf("Negotiating binary mode on output.\r\n"); tel_enter_binary(2); } } else { if (my_want_state_is_wont(TELOPT_BINARY)) { printf("Already transmitting in network ascii mode.\r\n"); } else { printf("Negotiating network ascii mode on output.\r\n"); tel_leave_binary(2); } } return 1; } static int togglehelp(int); struct togglelist { char *name; /* name of toggle */ char *help; /* help message */ int (*handler)(int); /* routine to do actual setting */ int *variable; char *actionexplanation; int needconnect; /* Need to be connected */ }; 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" }, { "autologin", "automatic sending of login name", 0, &autologin, "send login name" }, { "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 ", 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, 0 }, /* empty line */ { "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 }, { "help", 0, togglehelp }, { 0 } }; static int togglehelp(int unused) { struct togglelist *c; for (c = Togglelist; c->name; c++) { if (c->help) { if (*c->help) printf("%-15s toggle %s\r\n", c->name, c->help); else printf("\r\n"); } } printf("\r\n"); printf("%-15s %s\r\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\r\n", c->name, set ? "enable" : "disable", c->help); else printf("\r\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.\r\n"); return 0; } argc--; argv++; while (argc--) { name = *argv++; c = GETTOGGLE(name); if (Ambiguous(c)) { fprintf(stderr, "'%s': ambiguous argument ('toggle ?' for help).\r\n", name); return 0; } else if (c == 0) { fprintf(stderr, "'%s': unknown argument ('toggle ?' for help).\r\n", name); return 0; } else if (!connected && c->needconnect) { printf("?Need to be connected first.\r\n"); printf("'send ?' for help\r\n"); return 0; } else { if (c->variable) { *c->variable = !*c->variable; /* invert it */ if (c->actionexplanation) { printf("%s %s.\r\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 = { 0 }; struct setlist { char *name; /* name */ 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 }, { " ", "" }, { " ", "The following need 'localchars' to be toggled true", 0, 0 }, { "flushoutput", "character to cause an Abort Output", 0, &termFlushChar }, { "interrupt", "character to cause an Interrupt Process", 0, &termIntChar }, { "quit", "character to cause an Abort process", 0, &termQuitChar }, { "eof", "character to cause an EOF ", 0, &termEofChar }, { " ", "" }, { " ", "The following are for local editing in linemode", 0, 0 }, { "erase", "character to use to erase a character", 0, &termEraseChar }, { "kill", "character to use to erase a line", 0, &termKillChar }, { "lnext", "character to use for literal next", 0, &termLiteralNextChar }, { "susp", "character to cause a Suspend Process", 0, &termSuspChar }, { "reprint", "character to use for line reprint", 0, &termRprntChar }, { "worderase", "character to use to erase a word", 0, &termWerasChar }, { "start", "character to use for XON", 0, &termStartChar }, { "stop", "character to use for XOFF", 0, &termStopChar }, { "forw1", "alternate end of line character", 0, &termForw1Char }, { "forw2", "alternate end of line character", 0, &termForw2Char }, { "ayt", "alternate AYT character", 0, &termAytChar }, { 0 } }; static struct setlist * getset(char *name) { return (struct setlist *) genget(name, (char **) Setlist, sizeof(struct setlist)); } void set_escape_char(char *s) { if (rlogin != _POSIX_VDISABLE) { rlogin = (s && *s) ? special(s) : _POSIX_VDISABLE; printf("Telnet rlogin escape character is '%s'.\r\n", control(rlogin)); } else { escape = (s && *s) ? special(s) : _POSIX_VDISABLE; printf("Telnet escape character is '%s'.\r\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'\r\n'set ?' for help.\r\n"); return 0; } if ((argc == 2) && (isprefix(argv[1], "?") || isprefix(argv[1], "help"))) { for (ct = Setlist; ct->name; ct++) printf("%-15s %s\r\n", ct->name, ct->help); printf("\r\n"); settogglehelp(1); printf("%-15s %s\r\n", "?", "display help information"); return 0; } ct = getset(argv[1]); if (ct == 0) { c = GETTOGGLE(argv[1]); if (c == 0) { fprintf(stderr, "'%s': unknown argument ('set ?' for help).\r\n", argv[1]); return 0; } else if (Ambiguous(c)) { fprintf(stderr, "'%s': ambiguous argument ('set ?' for help).\r\n", argv[1]); return 0; } else if (!connected && c->needconnect) { printf("?Need to be connected first.\r\n"); printf("'send ?' for help\r\n"); 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]'\r\n'set ?' for help.\r\n"); return 0; } if (c->actionexplanation) { printf("%s %s.\r\n", *c->variable? "Will" : "Won't", c->actionexplanation); } } if (c->handler) (*c->handler)(1); } else if (argc != 3) { printf("Format is 'set Name Value'\r\n'set ?' for help.\r\n"); return 0; } else if (Ambiguous(ct)) { fprintf(stderr, "'%s': ambiguous argument ('set ?' for help).\r\n", argv[1]); return 0; } else if (ct->handler) { (*ct->handler)(argv[2]); printf("%s set to \"%s\".\r\n", ct->name, (char *)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'.\r\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.\r\n"); return 0; } if (isprefix(argv[1], "?") || isprefix(argv[1], "help")) { for (ct = Setlist; ct->name; ct++) printf("%-15s %s\r\n", ct->name, ct->help); printf("\r\n"); settogglehelp(0); printf("%-15s %s\r\n", "?", "display help information"); return 0; } argc--; argv++; while (argc--) { name = *argv++; ct = getset(name); if (ct == 0) { c = GETTOGGLE(name); if (c == 0) { fprintf(stderr, "'%s': unknown argument ('unset ?' for help).\r\n", name); return 0; } else if (Ambiguous(c)) { fprintf(stderr, "'%s': ambiguous argument ('unset ?' for help).\r\n", name); return 0; } if (c->variable) { *c->variable = 0; if (c->actionexplanation) { printf("%s %s.\r\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).\r\n", name); return 0; } else if (ct->handler) { (*ct->handler)(NULL); printf("%s reset to \"%s\".\r\n", ct->name, (char *)ct->charp); } else { *(ct->charp) = _POSIX_VDISABLE; printf("%s character is '%s'.\r\n", ct->name, control(*(ct->charp))); } } return 1; } /* * The following are the data structures and routines for the * 'mode' command. */ #ifdef KLUDGELINEMODE static int dokludgemode(int unused) { kludgelinemode = 1; send_wont(TELOPT_LINEMODE, 1); send_dont(TELOPT_SGA, 1); send_dont(TELOPT_ECHO, 1); return 1; } #endif static int dolinemode(int unused) { #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 unused) { #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; if (my_want_state_is_wont(TELOPT_LINEMODE)) { printf("?Need to have LINEMODE option enabled first.\r\n"); printf("'mode ?' for help.\r\n"); return 0; } if (on) c = (linemode | bit); else c = (linemode & ~bit); lm_mode(&c, 1, 1); return 1; } int tn_setmode(int bit) { return dolmmode(bit, 1); } int tn_clearmode(int bit) { return dolmmode(bit, 0); } struct modelist { char *name; /* command name */ char *help; /* help string */ int (*handler)(int);/* routine which executes command */ int needconnect; /* Do we need to be connected to execute? */ int arg1; }; static int modehelp(int); static struct modelist ModeList[] = { { "character", "Disable LINEMODE option", docharmode, 1 }, #ifdef KLUDGELINEMODE { "", "(or disable obsolete line-by-line mode)", 0 }, #endif { "line", "Enable LINEMODE option", dolinemode, 1 }, #ifdef KLUDGELINEMODE { "", "(or enable obsolete line-by-line mode)", 0 }, #endif { "", "", 0 }, { "", "These require the LINEMODE option to be enabled", 0 }, { "isig", "Enable signal trapping", tn_setmode, 1, MODE_TRAPSIG }, { "+isig", 0, tn_setmode, 1, MODE_TRAPSIG }, { "-isig", "Disable signal trapping", tn_clearmode, 1, MODE_TRAPSIG }, { "edit", "Enable character editing", tn_setmode, 1, MODE_EDIT }, { "+edit", 0, tn_setmode, 1, MODE_EDIT }, { "-edit", "Disable character editing", tn_clearmode, 1, MODE_EDIT }, { "softtabs", "Enable tab expansion", tn_setmode, 1, MODE_SOFT_TAB }, { "+softtabs", 0, tn_setmode, 1, MODE_SOFT_TAB }, { "-softtabs", "Disable character editing", tn_clearmode, 1, MODE_SOFT_TAB }, { "litecho", "Enable literal character echo", tn_setmode, 1, MODE_LIT_ECHO }, { "+litecho", 0, tn_setmode, 1, MODE_LIT_ECHO }, { "-litecho", "Disable literal character echo", tn_clearmode, 1, MODE_LIT_ECHO }, { "help", 0, modehelp, 0 }, #ifdef KLUDGELINEMODE { "kludgeline", 0, dokludgemode, 1 }, #endif { "", "", 0 }, { "?", "Print help information", modehelp, 0 }, { 0 }, }; static int modehelp(int unused) { struct modelist *mt; printf("format is: 'mode Mode', where 'Mode' is one of:\r\n\r\n"); for (mt = ModeList; mt->name; mt++) { if (mt->help) { if (*mt->help) printf("%-15s %s\r\n", mt->name, mt->help); else printf("\r\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\r\n"); printf("'mode ?' for help.\r\n"); } else if ((mt = GETMODECMD(argv[1])) == 0) { fprintf(stderr, "Unknown mode '%s' ('mode ?' for help).\r\n", argv[1]); } else if (Ambiguous(mt)) { fprintf(stderr, "Ambiguous mode '%s' ('mode ?' for help).\r\n", argv[1]); } else if (mt->needconnect && !connected) { printf("?Need to be connected first.\r\n"); printf("'mode ?' for help.\r\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.\r\n", tl->actionexplanation); \ } #define doset(sl) if (sl->name && *sl->name != ' ') { \ if (sl->handler == 0) \ printf("%-15s [%s]\r\n", sl->name, control(*sl->charp)); \ else \ printf("%-15s \"%s\"\r\n", sl->name, (char *)sl->charp); \ } if (argc == 1) { for (tl = Togglelist; tl->name; tl++) { dotog(tl); } printf("\r\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'.\r\n", argv[i]); return 0; } else if (!sl && !tl) { printf("?Unknown argument '%s'.\r\n", argv[i]); return 0; } else { if (tl) { dotog(tl); } if (sl) { doset(sl); } } } } /*@*/optionstatus(); 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.\r\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 = arg[0]; printf("Escape character is '%s'.\r\n", control(escape)); (void) fflush(stdout); return 1; } static int togcrmod(int unused1, char *unused2[]) { crmod = !crmod; printf("Deprecated usage - please use 'toggle crmod' in the future.\r\n"); printf("%s map carriage return on output.\r\n", crmod ? "Will" : "Won't"); (void) fflush(stdout); return 1; } int telnetsuspend(int unused1, char *unused2[]) { 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; } static void close_connection(void) { if (connected) { (void) shutdown(net, SHUT_RDWR); printf("Connection closed.\r\n"); (void)close(net); connected = 0; resettermname = 1; /* reset options */ tninit(); } } static int bye(int argc, char *argv[]) { close_connection(); longjmp(toplevel, 1); } void quit(void) { close_connection(); Exit(0); } static int quitcmd(int unused1, char *unused2[]) { quit(); } static int logout(int unused1, char *unused2[]) { send_do(TELOPT_LOGOUT, 1); (void) netflush(); return 1; } /* * The SLC command. */ struct slclist { char *name; char *help; void (*handler)(int); int arg; }; static void slc_help(int); 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 }, { 0 }, }; static void slc_help(int unused) { struct slclist *c; for (c = SlcList; c->name; c++) { if (c->help) { if (*c->help) printf("%-15s %s\r\n", c->name, c->help); else printf("\r\n"); } } } static struct slclist * getslc(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.\r\n"); return 0; } c = getslc(argv[1]); if (c == 0) { fprintf(stderr, "'%s': unknown argument ('slc ?' for help).\r\n", argv[1]); return 0; } if (Ambiguous(c)) { fprintf(stderr, "'%s': ambiguous argument ('slc ?' for help).\r\n", argv[1]); return 0; } (*c->handler)(c->arg); slcstate(); return 1; } /* * The ENVIRON command. */ struct envlist { char *name; char *help; void (*handler)(); int narg; }; static void env_help(void); static void env_undefine(const char *); static void env_export(const char *); static void env_unexport(const char *); static void env_send(const char *); static void env_list(void); static struct env_lst *env_find(const char *var); struct envlist EnvList[] = { { "define", "Define an environment variable", (void (*)())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 }, { 0 }, }; static void env_help(void) { struct envlist *c; for (c = EnvList; c->name; c++) { if (c->help) { if (*c->help) printf("%-15s %s\r\n", c->name, c->help); else printf("\r\n"); } } } static struct envlist * getenvcmd(char *name) { return (struct envlist *) genget(name, (char **) EnvList, sizeof(struct envlist)); } static int env_cmd(int argc, char *argv[]) { struct envlist *c; if (argc < 2) { fprintf(stderr, "Need an argument to 'environ' command. 'environ ?' for help.\r\n"); return 0; } c = getenvcmd(argv[1]); if (c == 0) { fprintf(stderr, "'%s': unknown argument ('environ ?' for help).\r\n", argv[1]); return 0; } if (Ambiguous(c)) { fprintf(stderr, "'%s': ambiguous argument ('environ ?' for help).\r\n", argv[1]); return 0; } if (c->narg + 2 != argc) { fprintf(stderr, "Need %s%d argument%s to 'environ %s' command. 'environ ?' for help.\r\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 */ char *var; /* pointer to variable name */ 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; static 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, '='))) { *cp = '\0'; ep = env_define(*epp, 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[HOST_NAME_MAX+1]; char *cp2 = strchr(ep->value, ':'); gethostname(hbuf, sizeof hbuf); if (asprintf (&cp, "%s%s", hbuf, cp2) == -1) err(1, "asprintf"); 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"); } env_export("DISPLAY"); env_export("PRINTER"); env_export("XAUTHORITY"); } struct env_lst * env_define(const char *var, const char *value) { struct env_lst *ep; if ((ep = env_find(var))) { free(ep->var); free(ep->value); } else { if ((ep = malloc(sizeof(struct env_lst))) == NULL) err(1, "malloc"); 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; if ((ep->var = strdup(var)) == NULL) err(1, "strdup"); if ((ep->value = strdup(value)) == NULL) err(1, "strdup"); return(ep); } static void env_undefine(const char *var) { struct env_lst *ep; if ((ep = env_find(var))) { ep->prev->next = ep->next; if (ep->next) ep->next->prev = ep->prev; free(ep->var); free(ep->value); free(ep); } } static void env_export(const char *var) { struct env_lst *ep; if ((ep = env_find(var))) ep->export = 1; } static void env_unexport(const char *var) { struct env_lst *ep; if ((ep = env_find(var)) != NULL) ep->export = 0; } static void env_send(const char *var) { struct env_lst *ep; if (my_state_is_wont(TELOPT_NEW_ENVIRON) ) { fprintf(stderr, "Cannot send '%s': Telnet ENVIRON option not enabled\r\n", var); return; } ep = env_find(var); if (ep == 0) { fprintf(stderr, "Cannot send '%s': variable not defined\r\n", var); return; } env_opt_start_info(); env_opt_add(ep->var); env_opt_end(0); } static void env_list(void) { struct env_lst *ep; for (ep = envlisthead.next; ep; ep = ep->next) { printf("%c %-20s %s\r\n", ep->export ? '*' : ' ', ep->var, ep->value); } } char * env_default(int init, int welldefined) { static struct env_lst *nep = NULL; if (init) { nep = &envlisthead; return NULL; } if (nep) { while ((nep = nep->next)) { if (nep->export && (nep->welldefined == welldefined)) return(nep->var); } } return(NULL); } char * env_getvalue(const char *var, int exported_only) { struct env_lst *ep; if ((ep = env_find(var)) && (!exported_only || ep->export)) return(ep->value); return(NULL); } static void connection_status(int local_only) { if (!connected) printf("No connection.\r\n"); else { printf("Connected to %s.\r\n", hostname); if (!local_only) { int mode = getconnmode(); printf("Operating "); if (my_want_state_is_will(TELOPT_LINEMODE)) { printf("with LINEMODE option\r\n" "%s line editing\r\n" "%s catching of signals\r\n", (mode & MODE_EDIT) ? "Local" : "No", (mode & MODE_TRAPSIG) ? "Local" : "No"); slcstate(); #ifdef KLUDGELINEMODE } else if (kludgelinemode && my_want_state_is_dont(TELOPT_SGA)) { printf("in obsolete linemode\r\n"); #endif } else { printf("in single character mode\r\n"); if (localchars) printf("Catching signals locally\r\n"); } printf("%s character echo\r\n", (mode & MODE_ECHO) ? "Local" : "Remote"); if (my_want_state_is_will(TELOPT_LFLOW)) printf("%s flow control\r\n", (mode & MODE_FLOW) ? "Local" : "No"); } } printf("Escape character is '%s'.\r\n", control(escape)); (void) fflush(stdout); } /* * Print status about the connection. */ static int status(int argc, char *argv[]) { connection_status(0); return 1; } /* * Function that gets called when SIGINFO is received. */ void ayt_status(int sig) { connection_status(1); } static Command *getcmd(char *name); static void cmdrc(char *m1, char *m2) { static char rcname[128]; Command *c; FILE *rcfile; int gotmachine = 0; int l1 = strlen(m1); int l2 = strlen(m2); char m1save[HOST_NAME_MAX+1]; if (skiprc) return; strlcpy(m1save, m1, sizeof(m1save)); m1 = m1save; if (rcname[0] == 0) { char *home = getenv("HOME"); if (home == NULL || *home == '\0') return; snprintf (rcname, sizeof(rcname), "%s/.telnetrc", home ? home : ""); } 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) strncpy(line, &line[l1], sizeof(line) - l1); else if (strncasecmp(line, m2, l2) == 0) strncpy(line, &line[l2], sizeof(line) - l2); else if (strncasecmp(line, "DEFAULT", 7) == 0) strncpy(line, &line[7], sizeof(line) - 7); else continue; 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\r\n", margv[0]); continue; } if (c == 0) { printf("?Invalid command: %s\r\n", margv[0]); continue; } /* * This should never happen... */ if (c->needconnect && !connected) { printf("?Need to be connected first for %s.\r\n", margv[0]); continue; } (*c->handler)(margc, margv); } fclose(rcfile); } int tn(int argc, char *argv[]) { struct addrinfo hints, *res, *res0; char *cmd, *hostp = 0, *portp = 0, *user = 0, *aliasp = 0; int error, retry; const int niflags = NI_NUMERICHOST, tos = IPTOS_LOWDELAY; if (connected) { printf("?Already connected to %s\r\n", hostname); return 0; } if (connections) { printf("Repeated connections not supported\r\n"); return 0; } if (argc < 2) { strlcpy(line, "open ", sizeof(line)); printf("(to) "); (void) fgets(&line[strlen(line)], 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; if ((user = strdup(*argv++)) == NULL) err(1, "strdup"); --argc; continue; } if (strcmp(*argv, "-b") == 0) { --argc; ++argv; if (argc == 0) goto usage; aliasp = *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 [-a] [-b hostalias] [-l user] host-name [port]\r\n", cmd); return 0; } if (hostp == 0) goto usage; hostname = hostp; memset(&hints, 0, sizeof(hints)); hints.ai_family = family; hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_CANONNAME; if (portp == NULL) { portp = "telnet"; telnetport = 1; } else if (*portp == '-') { portp++; telnetport = 1; } else telnetport = 0; error = getaddrinfo(hostp, portp, &hints, &res0); if (error) { if (error == EAI_SERVICE) warnx("%s: bad port", portp); else warnx("%s: %s", hostp, gai_strerror(error)); return 0; } net = -1; retry = 0; for (res = res0; res; res = res->ai_next) { if (1 /* retry */) { char hbuf[NI_MAXHOST]; if (getnameinfo(res->ai_addr, res->ai_addrlen, hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) { strlcpy(hbuf, "(invalid)", sizeof(hbuf)); } printf("Trying %s...\r\n", hbuf); } net = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (net < 0) continue; if (aliasp) { struct addrinfo ahints, *ares; memset(&ahints, 0, sizeof(ahints)); ahints.ai_family = family; ahints.ai_socktype = SOCK_STREAM; ahints.ai_flags = AI_PASSIVE; error = getaddrinfo(aliasp, "0", &ahints, &ares); if (error) { warn("%s: %s", aliasp, gai_strerror(error)); close(net); net = -1; continue; } if (bind(net, ares->ai_addr, ares->ai_addrlen) < 0) { perror(aliasp); (void) close(net); /* dump descriptor */ net = -1; freeaddrinfo(ares); continue; } freeaddrinfo(ares); } switch (res->ai_family) { case AF_INET: if (setsockopt(net, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0 && errno != ENOPROTOOPT) perror("telnet: setsockopt (IP_TOS) (ignored)"); break; case AF_INET6: if (setsockopt(net, IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0 && errno != ENOPROTOOPT) perror("telnet: setsockopt (IPV6_TCLASS) (ignored)"); break; } if (connect(net, res->ai_addr, res->ai_addrlen) < 0) { char hbuf[NI_MAXHOST]; if (getnameinfo(res->ai_addr, res->ai_addrlen, hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) { strlcpy(hbuf, "(invalid)", sizeof(hbuf)); } fprintf(stderr, "telnet: connect to address %s: %s\n", hbuf, strerror(errno)); close(net); net = -1; retry++; continue; } connected++; break; } freeaddrinfo(res0); if (net < 0) { return 0; } cmdrc(hostp, hostname); if (autologin && user == NULL) { struct passwd *pw; user = getlogin(); if (user == NULL || (pw = getpwnam(user)) == NULL || pw->pw_uid != getuid()) { if ((pw = getpwuid(getuid())) != NULL) user = pw->pw_name; else user = NULL; } } if (user) { env_define("USER", user); env_export("USER"); } connection_status(1); if (setjmp(peerdied) == 0) telnet(user); (void)close(net); ExitString("Connection closed by foreign host.\r\n",1); } #define HELPINDENT (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 charaters ('slc ?' for more)", displayhelp[] = "display operating parameters", zhelp[] = "suspend telnet", envhelp[] = "change environment variables ('environ ?' for more)", modestring[] = "try to enter line or character mode ('mode ?' for more)"; static int help(int, char**); 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, quitcmd, 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 }, { "z", zhelp, telnetsuspend, 0 }, { "environ", envhelp, env_cmd, 0 }, { "?", helphelp, help, 0 }, { 0, 0, 0, 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 }, { 0, 0, 0, 0 } }; static Command * getcmd(char *name) { Command *cm; if ((cm = (Command *) genget(name, (char **) cmdtab, sizeof(Command)))) return cm; return (Command *) genget(name, (char **) cmdtab2, sizeof(Command)); } void command(int top, 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\r\n", line); } else { getline: if (rlogin != _POSIX_VDISABLE) printf("%s> ", prompt); if (fgets(line, sizeof(line), stdin) == NULL) { if (feof(stdin) || ferror(stdin)) quit(); break; } } if (line[0] == 0) break; makeargv(); if (margv[0] == 0) { break; } c = getcmd(margv[0]); if (Ambiguous(c)) { printf("?Ambiguous command\r\n"); continue; } if (c == 0) { printf("?Invalid command\r\n"); continue; } if (c->needconnect && !connected) { printf("?Need to be connected first.\r\n"); continue; } if ((*c->handler)(margc, margv)) { break; } } if (!top) { if (!connected) longjmp(toplevel, 1); setconnmode(0); } } /* * Help command. */ static int help(int argc, char *argv[]) { Command *c; if (argc == 1) { printf("Commands may be abbreviated. Commands are:\r\n\r\n"); for (c = cmdtab; c->name; c++) if (c->help) { printf("%-*s\t%s\r\n", (int)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\r\n", arg); else if (c == NULL) printf("?Invalid help command %s\r\n", arg); else printf("%s\r\n", c->help); } return 0; }