/*      $OpenBSD: tip.c,v 1.30 2006/08/18 03:06:18 jason Exp $  */
/*      $NetBSD: tip.c,v 1.13 1997/04/20 00:03:05 mellon Exp $  */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1983, 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.
 */

/*
 * tip - UNIX link to other systems
 *  tip [-v] [-speed] system-name
 * or
 *  cu phone-number [-s speed] [-l line] [-a acu]
 */
#define EXTERN
#include "tip.h"
#include "pathnames.h"

int     disc = TTYDISC;         /* tip normally runs this way */
char    PNbuf[256];                     /* This limits the size of a number */

static void     intprompt(int);
static void     tipin(void);
static int      escape(void);

int
main(int argc, char *argv[])
{
        char *sys = NOSTR, sbuf[12], *p;
        int i;

        /* XXX preserve previous braindamaged behavior */
        setboolean(value(DC), TRUE);

        gid = getgid();
        egid = getegid();
        uid = getuid();
        euid = geteuid();
        if (equal(__progname, "cu")) {
                cumode = 1;
                cumain(argc, argv);
                goto cucommon;
        }

        if (argc > 4) {
                fprintf(stderr, "usage: tip [-v] [-speed] [system-name]\n");
                exit(1);
        }
        if (!isatty(0)) {
                fprintf(stderr, "%s: must be interactive\n", __progname);
                exit(1);
        }

        for (; argc > 1; argv++, argc--) {
                if (argv[1][0] != '-')
                        sys = argv[1];
                else switch (argv[1][1]) {

                case 'v':
                        vflag++;
                        break;

                case 'n':
                        noesc++;
                        break;

                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        BR = atoi(&argv[1][1]);
                        break;

                default:
                        fprintf(stderr, "%s: %s, unknown option\n", __progname,
                            argv[1]);
                        break;
                }
        }

        if (sys == NOSTR)
                goto notnumber;
        if (isalpha(*sys))
                goto notnumber;
        /*
         * System name is really a phone number...
         * Copy the number then stomp on the original (in case the number
         *      is private, we don't want 'ps' or 'w' to find it).
         */
        if (strlen(sys) > sizeof PNbuf - 1) {
                fprintf(stderr, "%s: phone number too long (max = %d bytes)\n",
                        __progname, (int)sizeof(PNbuf) - 1);
                exit(1);
        }
        strlcpy(PNbuf, sys, sizeof PNbuf - 1);
        for (p = sys; *p; p++)
                *p = '\0';
        PN = PNbuf;
        (void)snprintf(sbuf, sizeof(sbuf), "tip%ld", BR);
        sys = sbuf;

notnumber:
        (void)signal(SIGINT, cleanup);
        (void)signal(SIGQUIT, cleanup);
        (void)signal(SIGHUP, cleanup);
        (void)signal(SIGTERM, cleanup);
        (void)signal(SIGCHLD, SIG_DFL);

        if ((i = hunt(sys)) == 0) {
                printf("all ports busy\n");
                exit(3);
        }
        if (i == -1) {
                printf("link down\n");
                (void)uu_unlock(uucplock);
                exit(3);
        }
        setbuf(stdout, NULL);
        loginit();

        /*
         * Now that we have the logfile and the ACU open
         *  return to the real uid and gid.  These things will
         *  be closed on exit.  Swap real and effective uid's
         *  so we can get the original permissions back
         *  for removing the uucp lock.
         */
        user_uid();

        /*
         * Kludge, their's no easy way to get the initialization
         *   in the right order, so force it here
         */
        if ((PH = getenv("PHONES")) == NOSTR)
                PH = _PATH_PHONES;
        vinit();                                /* init variables */
        setparity("none");                      /* set the parity table */

        /*
         * Hardwired connections require the
         *  line speed set before they make any transmissions
         *  (this is particularly true of things like a DF03-AC)
         */
        if (HW && ttysetup(number(value(BAUDRATE)))) {
                fprintf(stderr, "%s: bad baud rate %ld\n", __progname,
                    number(value(BAUDRATE)));
                daemon_uid();
                (void)uu_unlock(uucplock);
                exit(3);
        }
        if ((p = con())) {
                printf("\07%s\n[EOT]\n", p);
                daemon_uid();
                (void)uu_unlock(uucplock);
                exit(1);
        }
        if (!HW && ttysetup(number(value(BAUDRATE)))) {
                fprintf(stderr, "%s: bad baud rate %ld\n", __progname,
                    number(value(BAUDRATE)));
                daemon_uid();
                (void)uu_unlock(uucplock);
                exit(3);
        }
cucommon:
        /*
         * From here down the code is shared with
         * the "cu" version of tip.
         */

        i = fcntl(FD, F_GETFL);
        if (i == -1) {
                perror("fcntl");
                cleanup(0);
        }
        i = fcntl(FD, F_SETFL, i & ~O_NONBLOCK);
        if (i == -1) {
                perror("fcntl");
                cleanup(0);
        }

        tcgetattr(0, &defterm);
        gotdefterm = 1;
        term = defterm;
        term.c_lflag &= ~(ICANON|IEXTEN|ECHO);
        term.c_iflag &= ~(INPCK|ICRNL);
        term.c_oflag &= ~OPOST;
        term.c_cc[VMIN] = 1;
        term.c_cc[VTIME] = 0;
        defchars = term;
        term.c_cc[VINTR] = term.c_cc[VQUIT] = term.c_cc[VSUSP] =
            term.c_cc[VDSUSP] = term.c_cc[VDISCARD] =
            term.c_cc[VLNEXT] = _POSIX_VDISABLE;
        raw();

        pipe(fildes); pipe(repdes);
        (void)signal(SIGALRM, timeout);

        if (value(LINEDISC) != TTYDISC) {
                int ld = (int)(intptr_t)value(LINEDISC);
                ioctl(FD, TIOCSETD, &ld);
        }               

        /*
         * Everything's set up now:
         *      connection established (hardwired or dialup)
         *      line conditioned (baud rate, mode, etc.)
         *      internal data structures (variables)
         * so, fork one process for local side and one for remote.
         */
        printf(cumode ? "Connected\r\n" : "\07connected\r\n");
        tipin_pid = getpid();
        if ((tipout_pid = fork()))
                tipin();
        else
                tipout();
        exit(0);
}

void
cleanup(int signo)
{
        daemon_uid();
        (void)uu_unlock(uucplock);
        if (odisc)
                ioctl(0, TIOCSETD, &odisc);
        unraw();
        if (signo && tipout_pid) {
                kill(tipout_pid, signo);
                wait(NULL);
        }
        exit(0);
}

/*
 * Muck with user ID's.  We are setuid to the owner of the lock
 * directory when we start.  user_uid() reverses real and effective
 * ID's after startup, to run with the user's permissions.
 * daemon_uid() switches back to the privileged uid for unlocking.
 * Finally, to avoid running a shell with the wrong real uid,
 * shell_uid() sets real and effective uid's to the user's real ID.
 */
static int uidswapped;

void
user_uid(void)
{
        if (uidswapped == 0) {
                seteuid(uid);
                uidswapped = 1;
        }
}

void
daemon_uid(void)
{

        if (uidswapped) {
                seteuid(euid);
                uidswapped = 0;
        }
}

void
shell_uid(void)
{
        setegid(gid);
        seteuid(uid);
}

/*
 * put the controlling keyboard into raw mode
 */
void
raw(void)
{
        tcsetattr(0, TCSADRAIN, &term);
}


/*
 * return keyboard to normal mode
 */
void
unraw(void)
{
        if (gotdefterm)
                tcsetattr(0, TCSADRAIN, &defterm);
}

/*
 * give up exclusive tty access
 */
void
unexcl()
{
        ioctl(FD, TIOCNXCL, 0);
}

static  jmp_buf promptbuf;

/*
 * Print string ``s'', then read a string
 *  in from the terminal.  Handles signals & allows use of
 *  normal erase and kill characters.
 */
int
prompt(char *s, char *p, size_t sz)
{
        int c;
        char *b = p;
        sig_t oint, oquit;

        stoprompt = 0;
        oint = signal(SIGINT, intprompt);
        oquit = signal(SIGQUIT, SIG_IGN);
        unraw();
        printf("%s", s);
        if (setjmp(promptbuf) == 0)
                while ((c = getchar()) != EOF && (*p = c) != '\n' && --sz > 0)
                        p++;
        *p = '\0';

        raw();
        (void)signal(SIGINT, oint);
        (void)signal(SIGQUIT, oquit);
        return (stoprompt || p == b);
}

/*
 * Interrupt service routine during prompting
 */
/*ARGSUSED*/
static void
intprompt(int signo)
{
        (void)signal(SIGINT, SIG_IGN);
        stoprompt = 1;
        printf("\r\n");
        longjmp(promptbuf, 1);
}

/*
 * ****TIPIN   TIPIN****
 */
static void
tipin(void)
{
        int bol = 1;
        int gch;
        char ch;

        /*
         * Kinda klugey here...
         *   check for scripting being turned on from the .tiprc file,
         *   but be careful about just using setscript(), as we may
         *   send a SIGEMT before tipout has a chance to set up catching
         *   it; so wait a second, then setscript()
         */
        if (boolean(value(SCRIPT))) {
                sleep(1);
                setscript();
        }

        while (1) {
                gch = getchar();
                if (gch == EOF)
                        return;
                gch = gch & STRIP_PAR;
                if ((gch == character(value(ESCAPE))) && bol) {
                        if (!noesc) {
                                gch = escape();
                                if (gch == EOF)
                                        return;
                                if (gch == 0)
                                        continue;
                        }
                } else if (!cumode && gch == character(value(RAISECHAR))) {
                        setboolean(value(RAISE), !boolean(value(RAISE)));
                        continue;
                } else if (gch == '\r') {
                        bol = 1;
                        ch = gch;
                        parwrite(FD, &ch, 1);
                        if (boolean(value(HALFDUPLEX)))
                                printf("\r\n");
                        continue;
                } else if (!cumode && gch == character(value(FORCE))) {
                        gch = getchar();
                        if (gch == EOF)
                                return;
                        gch = gch & STRIP_PAR;
                }
                bol = any(gch, value(EOL));
                if (boolean(value(RAISE)) && islower(gch))
                        gch = toupper(gch);
                ch = gch;
                parwrite(FD, &ch, 1);
                if (boolean(value(HALFDUPLEX)))
                        printf("%c", ch);
        }
}

extern esctable_t etable[];

/*
 * Escape handler --
 *  called on recognition of ``escapec'' at the beginning of a line
 */
static int
escape(void)
{
        int gch;
        esctable_t *p;
        char c = character(value(ESCAPE));

        gch = getchar();
        if (gch == EOF)
                return (EOF);
        gch = gch & STRIP_PAR;
        for (p = etable; p->e_char; p++)
                if (p->e_char == gch) {
                        if ((p->e_flags&PRIV) && uid)
                                continue;
                        printf("%s", ctrl(c));
                        (*p->e_func)(gch);
                        return (0);
                }
        /* ESCAPE ESCAPE forces ESCAPE */
        if (c != gch)
                parwrite(FD, &c, 1);
        return (gch);
}

int
any(int cc, char *p)
{
        char c = cc;
        while (p && *p)
                if (*p++ == c)
                        return (1);
        return (0);
}

size_t
size(char *s)
{
        size_t i = 0;

        while (s && *s++)
                i++;
        return (i);
}

char *
interp(char *s)
{
        static char buf[256];
        char *p = buf, c, *q;

        while ((c = *s++)) {
                for (q = "\nn\rr\tt\ff\033E\bb"; *q; q++)
                        if (*q++ == c) {
                                *p++ = '\\'; *p++ = *q;
                                goto next;
                        }
                if (c < 040) {
                        *p++ = '^'; *p++ = c + 'A'-1;
                } else if (c == 0177) {
                        *p++ = '^'; *p++ = '?';
                } else
                        *p++ = c;
        next:
                ;
        }
        *p = '\0';
        return (buf);
}

char *
ctrl(char c)
{
        static char s[3];

        if (c < 040 || c == 0177) {
                s[0] = '^';
                s[1] = c == 0177 ? '?' : c+'A'-1;
                s[2] = '\0';
        } else {
                s[0] = c;
                s[1] = '\0';
        }
        return (s);
}

/*
 * Help command
 */
void
help(int c)
{
        esctable_t *p;

        printf("%c\r\n", c);
        for (p = etable; p->e_char; p++) {
                if ((p->e_flags&PRIV) && uid)
                        continue;
                printf("%2s", ctrl(character(value(ESCAPE))));
                printf("%-2s %c   %s\r\n", ctrl(p->e_char),
                        p->e_flags&EXP ? '*': ' ', p->e_help);
        }
}

/*
 * Set up the "remote" tty's state
 */
int
ttysetup(int speed)
{
        struct termios  cntrl;

        if (tcgetattr(FD, &cntrl))
                return (-1);
        cfsetspeed(&cntrl, speed);
        cntrl.c_cflag &= ~(CSIZE|PARENB);
        cntrl.c_cflag |= CS8;
        if (boolean(value(DC)))
                cntrl.c_cflag |= CLOCAL;
        if (boolean(value(HARDWAREFLOW)))
                cntrl.c_cflag |= CRTSCTS;
        cntrl.c_iflag &= ~(ISTRIP|ICRNL);
        cntrl.c_oflag &= ~OPOST;
        cntrl.c_lflag &= ~(ICANON|ISIG|IEXTEN|ECHO);
        cntrl.c_cc[VMIN] = 1;
        cntrl.c_cc[VTIME] = 0;
        if (boolean(value(TAND)))
                cntrl.c_iflag |= IXOFF;
        return (tcsetattr(FD, TCSAFLUSH, &cntrl));
}

static char partab[0200];

/*
 * Do a write to the remote machine with the correct parity.
 * We are doing 8 bit wide output, so we just generate a character
 * with the right parity and output it.
 */
void
parwrite(int fd, char *buf, size_t n)
{
        size_t i;
        char *bp;

        bp = buf;
        if (bits8 == 0)
                for (i = 0; i < n; i++) {
                        *bp = partab[(*bp) & 0177];
                        bp++;
                }
        if (write(fd, buf, n) < 0) {
                if (errno == EIO || errno == ENXIO)
                        tipabort("Lost carrier.");
                /* this is questionable */
                perror("write");
        }
}

/*
 * Build a parity table with appropriate high-order bit.
 */
void
setparity(char *defparity)
{
        int i, flip, clr, set;
        char *parity;
        extern const unsigned char evenpartab[];

        if (value(PARITY) == NOSTR)
                value(PARITY) = defparity;
        parity = value(PARITY);
        if (equal(parity, "none")) {
                bits8 = 1;
                return;
        }
        bits8 = 0;
        flip = 0;
        clr = 0377;
        set = 0;
        if (equal(parity, "odd"))
                flip = 0200;                    /* reverse bit 7 */
        else if (equal(parity, "zero"))
                clr = 0177;                     /* turn off bit 7 */
        else if (equal(parity, "one"))
                set = 0200;                     /* turn on bit 7 */
        else if (!equal(parity, "even")) {
                (void) fprintf(stderr, "%s: unknown parity value\r\n", parity);
                (void) fflush(stderr);
        }
        for (i = 0; i < 0200; i++)
                partab[i] = ((evenpartab[i] ^ flip) | set) & clr;
}