root/games/hack/hack.unix.c
/*      $NetBSD: hack.unix.c,v 1.18 2019/02/03 10:48:46 mrg Exp $       */

/*
 * Copyright (c) 1985, Stichting Centrum voor Wiskunde en Informatica,
 * Amsterdam
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * - 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.
 *
 * - Neither the name of the Stichting Centrum voor Wiskunde en
 * Informatica, 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 COPYRIGHT HOLDERS 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 COPYRIGHT OWNER
 * 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) 1982 Jay Fenlason <hack@gnu.org>
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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
__RCSID("$NetBSD: hack.unix.c,v 1.18 2019/02/03 10:48:46 mrg Exp $");
#endif                          /* not lint */

/* This file collects some Unix dependencies; hack.pager.c contains some more */

/*
 * The time is used for:
 *      - seed for random()
 *      - year on tombstone and yymmdd in record file
 *      - phase of the moon (various monsters react to NEW_MOON or FULL_MOON)
 *      - night and midnight (the undead are dangerous at midnight)
 *      - determination of what files are "very old"
 */

#include <errno.h>
#include <sys/types.h>  /* for time_t and stat */
#include <sys/stat.h>
#ifdef BSD
#include <sys/time.h>
#else
#include <time.h>
#endif  /* BSD */
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>

#include "hack.h"               /* mainly for strchr() which depends on BSD */
#include "extern.h"

extern int locknum;

static struct tm *getlt(void);
static int veryold(int);


void
setrandom(void)
{
        (void) srandom((int) time((time_t *) 0));
}

static struct tm *
getlt(void)
{
        time_t          date;

        (void) time(&date);
        return (localtime(&date));
}

int
getyear(void)
{
        return (1900 + getlt()->tm_year);
}

char           *
getdatestr(void)
{
        static char     datestr[32];
        struct tm      *lt = getlt();

        (void) snprintf(datestr, sizeof(datestr), "%02d%02d%02d",
                       lt->tm_year % 100, lt->tm_mon + 1, lt->tm_mday);
        return (datestr);
}

int
phase_of_the_moon(void)
{                               /* 0-7, with 0: new, 4: full *//* moon
                                 * period: 29.5306 days */
        /* year: 365.2422 days */
        struct tm      *lt = getlt();
        int             epact, diy, golden;

        diy = lt->tm_yday;
        golden = (lt->tm_year % 19) + 1;
        epact = (11 * golden + 18) % 30;
        if ((epact == 25 && golden > 11) || epact == 24)
                epact++;

        return ((((((diy + epact) * 6) + 11) % 177) / 22) & 7);
}

int
night(void)
{
        int             hour = getlt()->tm_hour;

        return (hour < 6 || hour > 21);
}

int
midnight(void)
{
        return (getlt()->tm_hour == 0);
}

static struct stat buf, hbuf;

void
gethdate(char *name)
{
#if 0
        /* old version - for people short of space */

        char *np;

        if(stat(name, &hbuf))
            error("Cannot get status of %s.",
                (np = strrchr(name, '/')) ? np+1 : name);
#else
        /* version using PATH from: seismo!gregc@ucsf-cgl.ARPA (Greg Couch) */


        /*
         * The problem with   #include  <sys/param.h>   is that this include file
         * does not exist on all systems, and moreover, that it sometimes includes
         * <sys/types.h> again, so that the compiler sees these typedefs twice.
         */
#define         MAXPATHLEN      1024

        const char           *np, *path;
        char            filename[MAXPATHLEN + 1];
        if (strchr(name, '/') != NULL || (path = getenv("PATH")) == NULL)
                path = "";

        for (;;) {
                if ((np = strchr(path, ':')) == NULL)
                        np = path + strlen(path);       /* point to end str */
                if (np - path <= 1)     /* %% */
                        (void) strlcpy(filename, name, sizeof(filename));
                else {
                        (void) snprintf(filename, sizeof(filename),
                                "%.*s/%s",
                                (int)(np - path), path, name);
                }
                if (stat(filename, &hbuf) == 0)
                        return;
                if (*np == '\0')
                        break;
                path = np + 1;
        }
        error("Cannot get status of %s.",
              (np = strrchr(name, '/')) ? np + 1 : name);
#endif
}

int
uptodate(int fd)
{
        if (fstat(fd, &buf)) {
                pline("Cannot get status of saved level? ");
                return (0);
        }
        if (buf.st_mtime < hbuf.st_mtime) {
                pline("Saved level is out of date. ");
                return (0);
        }
        return (1);
}

/* see whether we should throw away this xlock file */
static int
veryold(int fd)
{
        int             i;
        time_t          date;

        if (fstat(fd, &buf))
                return (0);     /* cannot get status */
        if (buf.st_size != sizeof(int))
                return (0);     /* not an xlock file */
        (void) time(&date);
        if (date - buf.st_mtime < 3L * 24L * 60L * 60L) {       /* recent */
                int             lockedpid;      /* should be the same size as
                                                 * hackpid */

                if (read(fd, &lockedpid, sizeof(lockedpid)) !=
                    sizeof(lockedpid))
                        /* strange ... */
                        return (0);

                /*
                 * From: Rick Adams <seismo!rick> This will work on
                 * 4.1cbsd, 4.2bsd and system 3? & 5. It will do nothing
                 * on V7 or 4.1bsd.
                 */
                if (!(kill(lockedpid, 0) == -1 && errno == ESRCH))
                        return (0);
        }
        (void) close(fd);
        for (i = 1; i <= MAXLEVEL; i++) {       /* try to remove all */
                glo(i);
                (void) unlink(lock);
        }
        glo(0);
        if (unlink(lock))
                return (0);     /* cannot remove it */
        return (1);             /* success! */
}

void
getlock(void)
{
        int             i = 0, fd;

        (void) fflush(stdout);

        /* we ignore QUIT and INT at this point */
        if (link(HLOCK, LLOCK) == -1) {
                int             errnosv = errno;

                perror(HLOCK);
                printf("Cannot link %s to %s\n", LLOCK, HLOCK);
                switch (errnosv) {
                case ENOENT:
                        printf("Perhaps there is no (empty) file %s ?\n", HLOCK);
                        break;
                case EACCES:
                        printf("It seems you don't have write permission here.\n");
                        break;
                case EEXIST:
                        printf("(Try again or rm %s.)\n", LLOCK);
                        break;
                default:
                        printf("I don't know what is wrong.");
                }
                getret();
                error("%s", "");
                /* NOTREACHED */
        }
        regularize(lock);
        glo(0);
        if (locknum > 25)
                locknum = 25;

        do {
                if (locknum)
                        lock[0] = 'a' + i++;

                if ((fd = open(lock, O_RDONLY)) == -1) {
                        if (errno == ENOENT)
                                goto gotlock;   /* no such file */
                        perror(lock);
                        (void) unlink(LLOCK);
                        error("Cannot open %s", lock);
                }
                if (veryold(fd))/* if true, this closes fd and unlinks lock */
                        goto gotlock;
                (void) close(fd);
        } while (i < locknum);

        (void) unlink(LLOCK);
        error(locknum ? "Too many hacks running now."
              : "There is a game in progress under your name.");
gotlock:
        fd = creat(lock, FMASK);
        if (unlink(LLOCK) == -1)
                error("Cannot unlink %s.", LLOCK);
        if (fd == -1) {
                error("cannot creat lock file.");
        } else {
                if (write(fd, &hackpid, sizeof(hackpid))
                    != sizeof(hackpid)) {
                        error("cannot write lock");
                }
                if (close(fd) == -1) {
                        error("cannot close lock");
                }
        }
}

#ifdef MAIL

/*
 * Notify user when new mail has arrived. [Idea from Merlyn Leroy, but
 * I don't know the details of his implementation.]
 * { Later note: he disliked my calling a general mailreader and felt that
 *   hack should do the paging itself. But when I get mail, I want to put it
 *   in some folder, reply, etc. - it would be unreasonable to put all these
 *   functions in hack. }
 * The mail daemon '2' is at present not a real monster, but only a visual
 * effect. Thus, makemon() is superfluous. This might become otherwise,
 * however. The motion of '2' is less restrained than usual: diagonal moves
 * from a DOOR are possible. He might also use SDOOR's. Also, '2' is visible
 * in a ROOM, even when you are Blind.
 * Its path should be longer when you are Telepat-hic and Blind.
 *
 * Interesting side effects:
 *      - You can get rich by sending yourself a lot of mail and selling
 *        it to the shopkeeper. Unfortunately mail isn't very valuable.
 *      - You might die in case '2' comes along at a critical moment during
 *        a fight and delivers a scroll the weight of which causes you to
 *        collapse.
 *
 * Possible extensions:
 *      - Open the file MAIL and do fstat instead of stat for efficiency.
 *        (But sh uses stat, so this cannot be too bad.)
 *      - Examine the mail and produce a scroll of mail called "From somebody".
 *      - Invoke MAILREADER in such a way that only this single letter is read.
 *
 *      - Make him lose his mail when a Nymph steals the letter.
 *      - Do something to the text when the scroll is enchanted or cancelled.
 */
#include        "def.mkroom.h"
static struct stat omstat, nmstat;
static char    *mailbox;
static long     laststattime;

void
getmailstatus(void)
{
        if (!(mailbox = getenv("MAIL")))
                return;
        if (stat(mailbox, &omstat)) {
#ifdef PERMANENT_MAILBOX
                pline("Cannot get status of MAIL=%s .", mailbox);
                mailbox = 0;
#else
                omstat.st_mtime = 0;
#endif  /* PERMANENT_MAILBOX */
        }
}

void
ckmailstatus(void)
{
        if (!mailbox
#ifdef MAILCKFREQ
            || moves < laststattime + MAILCKFREQ
#endif  /* MAILCKFREQ */
                )
                return;
        laststattime = moves;
        if (stat(mailbox, &nmstat)) {
#ifdef PERMANENT_MAILBOX
                pline("Cannot get status of MAIL=%s anymore.", mailbox);
                mailbox = 0;
#else
                nmstat.st_mtime = 0;
#endif  /* PERMANENT_MAILBOX */
        } else if (nmstat.st_mtime > omstat.st_mtime) {
                if (nmstat.st_size)
                        newmail();
                getmailstatus();/* might be too late ... */
        }
}

void
newmail(void)
{
        /* produce a scroll of mail */
        struct obj     *obj;
        struct monst   *md;

        obj = mksobj(SCR_MAIL);
        if (md = makemon(&pm_mail_daemon, u.ux, u.uy))  /* always succeeds */
                mdrush(md, 0);

        pline("\"Hello, %s! I have some mail for you.\"", plname);
        if (md) {
                if (dist(md->mx, md->my) > 2)
                        pline("\"Catch!\"");
                more();

                /* let him disappear again */
                mdrush(md, 1);
                mondead(md);
        }
        obj = addinv(obj);
        (void) identify(obj);   /* set known and do prinv() */
}

/* make md run through the cave */
void
mdrush(struct monst *md, boolean away)
{
        int             uroom = inroom(u.ux, u.uy);
        if (uroom >= 0) {
                int             tmp = rooms[uroom].fdoor;
                int             cnt = rooms[uroom].doorct;
                int             fx = u.ux, fy = u.uy;
                while (cnt--) {
                        if (dist(fx, fy) < dist(doors[tmp].x, doors[tmp].y)) {
                                fx = doors[tmp].x;
                                fy = doors[tmp].y;
                        }
                        tmp++;
                }
                tmp_at(-1, md->data->mlet);     /* open call */
                if (away) {     /* interchange origin and destination */
                        unpmon(md);
                        tmp = fx;
                        fx = md->mx;
                        md->mx = tmp;
                        tmp = fy;
                        fy = md->my;
                        md->my = tmp;
                }
                while (fx != md->mx || fy != md->my) {
                        int             dx, dy, nfx = fx, nfy = fy, d1,
                                        d2;

                        tmp_at(fx, fy);
                        d1 = DIST(fx, fy, md->mx, md->my);
                        for (dx = -1; dx <= 1; dx++)
                                for (dy = -1; dy <= 1; dy++)
                                        if (dx || dy) {
                                                d2 = DIST(fx + dx, fy + dy, md->mx, md->my);
                                                if (d2 < d1) {
                                                        d1 = d2;
                                                        nfx = fx + dx;
                                                        nfy = fy + dy;
                                                }
                                        }
                        if (nfx != fx || nfy != fy) {
                                fx = nfx;
                                fy = nfy;
                        } else {
                                if (!away) {
                                        md->mx = fx;
                                        md->my = fy;
                                }
                                break;
                        }
                }
                tmp_at(-1, -1); /* close call */
        }
        if (!away)
                pmon(md);
}

void
readmail(void)
{
#ifdef DEF_MAILREADER           /* This implies that UNIX is defined */
        char           *mr = 0;
        more();
        if (!(mr = getenv("MAILREADER")))
                mr = DEF_MAILREADER;
        if (child(1)) {
                execl(mr, mr, (char *)NULL);
                exit(1);
        }
#else   /* DEF_MAILREADER */
        (void) page_file(mailbox, FALSE);
#endif  /* DEF_MAILREADER */
        /*
         * get new stat; not entirely correct: there is a small time window
         * where we do not see new mail
         */
        getmailstatus();
}
#endif  /* MAIL */

/*
 * normalize file name - we don't like ..'s or /'s
 */
void
regularize(char *s)
{
        char           *lp;

        while ((lp = strchr(s, '.')) || (lp = strchr(s, '/')))
                *lp = '_';
}