/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 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.
 */

/*
 * Mail -- a mail program
 *
 * Generally useful tty stuff.
 */

#include "rcv.h"
#include "extern.h"

static  cc_t    c_erase;                /* Current erase char */
static  cc_t    c_kill;                 /* Current kill char */
static  jmp_buf rewrite;                /* Place to go when continued */
static  jmp_buf intjmp;                 /* Place to go when interrupted */
#ifndef TIOCSTI
static  int     ttyset;                 /* We must now do erase/kill */
#endif

/*
 * Read all relevant header fields.
 */

int
grabh(struct header *hp, int gflags)
{
        struct termios ttybuf;
        volatile sig_t saveint;
        sig_t savetstp;
        sig_t savettou;
        sig_t savettin;
        int errs;
#ifndef TIOCSTI
        sig_t savequit;
#else
# ifdef TIOCEXT
        int extproc, flag;
# endif /* TIOCEXT */
#endif /* TIOCSTI */

        savetstp = signal(SIGTSTP, SIG_DFL);
        savettou = signal(SIGTTOU, SIG_DFL);
        savettin = signal(SIGTTIN, SIG_DFL);
        errs = 0;
#ifndef TIOCSTI
        ttyset = 0;
#endif
        if (tcgetattr(fileno(stdin), &ttybuf) < 0) {
                warn("tcgetattr(stdin)");
                return (-1);
        }
        c_erase = ttybuf.c_cc[VERASE];
        c_kill = ttybuf.c_cc[VKILL];
#ifndef TIOCSTI
        ttybuf.c_cc[VERASE] = _POSIX_VDISABLE;
        ttybuf.c_cc[VKILL] = _POSIX_VDISABLE;
        if ((saveint = signal(SIGINT, SIG_IGN)) == SIG_DFL)
                (void)signal(SIGINT, SIG_DFL);
        if ((savequit = signal(SIGQUIT, SIG_IGN)) == SIG_DFL)
                (void)signal(SIGQUIT, SIG_DFL);
#else
# ifdef         TIOCEXT
        extproc = ((ttybuf.c_lflag & EXTPROC) ? 1 : 0);
        if (extproc) {
                flag = 0;
                if (ioctl(fileno(stdin), TIOCEXT, &flag) < 0)
                        warn("TIOCEXT: off");
        }
# endif /* TIOCEXT */
        if (setjmp(intjmp))
                goto out;
        saveint = signal(SIGINT, ttyint);
#endif
        if (gflags & GTO) {
#ifndef TIOCSTI
                if (!ttyset && hp->h_to != NULL)
                        ttyset++, tcsetattr(fileno(stdin), TCSADRAIN, &ttybuf);
#endif
                hp->h_to =
                        extract(readtty("To: ", detract(hp->h_to, 0)), GTO);
        }
        if (gflags & GSUBJECT) {
#ifndef TIOCSTI
                if (!ttyset && hp->h_subject != NULL)
                        ttyset++, tcsetattr(fileno(stdin), TCSADRAIN, &ttybuf);
#endif
                hp->h_subject = readtty("Subject: ", hp->h_subject);
        }
        if (gflags & GCC) {
#ifndef TIOCSTI
                if (!ttyset && hp->h_cc != NULL)
                        ttyset++, tcsetattr(fileno(stdin), TCSADRAIN, &ttybuf);
#endif
                hp->h_cc =
                        extract(readtty("Cc: ", detract(hp->h_cc, 0)), GCC);
        }
        if (gflags & GBCC) {
#ifndef TIOCSTI
                if (!ttyset && hp->h_bcc != NULL)
                        ttyset++, tcsetattr(fileno(stdin), TCSADRAIN, &ttybuf);
#endif
                hp->h_bcc =
                        extract(readtty("Bcc: ", detract(hp->h_bcc, 0)), GBCC);
        }
#ifdef TIOCSTI
out:
#endif
        (void)signal(SIGTSTP, savetstp);
        (void)signal(SIGTTOU, savettou);
        (void)signal(SIGTTIN, savettin);
#ifndef TIOCSTI
        ttybuf.c_cc[VERASE] = c_erase;
        ttybuf.c_cc[VKILL] = c_kill;
        if (ttyset)
                tcsetattr(fileno(stdin), TCSADRAIN, &ttybuf);
        (void)signal(SIGQUIT, savequit);
#else
# ifdef         TIOCEXT
        if (extproc) {
                flag = 1;
                if (ioctl(fileno(stdin), TIOCEXT, &flag) < 0)
                        warn("TIOCEXT: on");
        }
# endif /* TIOCEXT */
#endif
        (void)signal(SIGINT, saveint);
        return (errs);
}

/*
 * Read up a header from standard input.
 * The source string has the preliminary contents to
 * be read.
 *
 */

char *
readtty(const char *pr, char src[])
{
        char canonb[BUFSIZ];
#ifdef TIOCSTI
        char ch;
#endif
        int c;
        char *cp, *cp2;

        fputs(pr, stdout);
        (void)fflush(stdout);
        if (src != NULL && strlen(src) > BUFSIZ - 2) {
                printf("too long to edit\n");
                return (src);
        }
#ifndef TIOCSTI
        if (src != NULL)
                strlcpy(canonb, src, sizeof(canonb));
        else
                *canonb = '\0';
        fputs(canonb, stdout);
        (void)fflush(stdout);
#else
        cp = src == NULL ? "" : src;
        while ((c = *cp++) != '\0') {
                if ((c_erase != _POSIX_VDISABLE && c == c_erase) ||
                    (c_kill != _POSIX_VDISABLE && c == c_kill)) {
                        ch = '\\';
                        ioctl(0, TIOCSTI, &ch);
                }
                ch = c;
                ioctl(0, TIOCSTI, &ch);
        }
        cp = canonb;
        *cp = '\0';
#endif
        cp2 = cp;
        while (cp2 < canonb + BUFSIZ)
                *cp2++ = '\0';
        cp2 = cp;
        if (setjmp(rewrite))
                goto redo;
        (void)signal(SIGTSTP, ttystop);
        (void)signal(SIGTTOU, ttystop);
        (void)signal(SIGTTIN, ttystop);
        clearerr(stdin);
        while (cp2 < canonb + BUFSIZ) {
                c = getc(stdin);
                if (c == EOF || c == '\n')
                        break;
                *cp2++ = c;
        }
        *cp2 = '\0';
        (void)signal(SIGTSTP, SIG_DFL);
        (void)signal(SIGTTOU, SIG_DFL);
        (void)signal(SIGTTIN, SIG_DFL);
        if (c == EOF && ferror(stdin)) {
redo:
                cp = strlen(canonb) > 0 ? canonb : NULL;
                clearerr(stdin);
                return (readtty(pr, cp));
        }
#ifndef TIOCSTI
        if (cp == NULL || *cp == '\0')
                return (src);
        cp2 = cp;
        if (!ttyset)
                return (strlen(canonb) > 0 ? savestr(canonb) : NULL);
        while (*cp != '\0') {
                c = *cp++;
                if (c_erase != _POSIX_VDISABLE && c == c_erase) {
                        if (cp2 == canonb)
                                continue;
                        if (cp2[-1] == '\\') {
                                cp2[-1] = c;
                                continue;
                        }
                        cp2--;
                        continue;
                }
                if (c_kill != _POSIX_VDISABLE && c == c_kill) {
                        if (cp2 == canonb)
                                continue;
                        if (cp2[-1] == '\\') {
                                cp2[-1] = c;
                                continue;
                        }
                        cp2 = canonb;
                        continue;
                }
                *cp2++ = c;
        }
        *cp2 = '\0';
#endif
        if (equal("", canonb))
                return (NULL);
        return (savestr(canonb));
}

/*
 * Receipt continuation.
 */
void
ttystop(int s)
{
        sig_t old_action = signal(s, SIG_DFL);
        sigset_t nset;

        (void)sigemptyset(&nset);
        (void)sigaddset(&nset, s);
        (void)sigprocmask(SIG_BLOCK, &nset, NULL);
        kill(0, s);
        (void)sigprocmask(SIG_UNBLOCK, &nset, NULL);
        (void)signal(s, old_action);
        longjmp(rewrite, 1);
}

void
ttyint(int s __unused)
{
        longjmp(intjmp, 1);
}