/*      $OpenBSD: sync.c,v 1.16 2019/06/28 13:32:52 deraadt Exp $       */
/*      $NetBSD: sync.c,v 1.9 1998/08/30 09:19:40 veego Exp $   */

/*
 * 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.
 */

#include <sys/stat.h>

#include <errno.h>
#ifdef LOCK_EX
#include <fcntl.h>
#endif
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "extern.h"
#include "machdep.h"
#include "pathnames.h"
#include "player.h"

#define BUFSIZE 4096

static const char SF[] = _PATH_SYNC;
static const char LF[] = _PATH_LOCK;
static char sync_buf[BUFSIZE];
static char *sync_bp = sync_buf;
static char sync_lock[sizeof SF];
static char sync_file[sizeof LF];
static long sync_seek;
static FILE *sync_fp;

void
fmtship(char *buf, size_t len, const char *fmt, struct ship *ship)
{
        if (len == 0)
                abort();        /* XXX */

        while (*fmt && len > 1) {
                if (*fmt == '$' && fmt[1] == '$') {
                        size_t l;
                        snprintf(buf, len, "%s (%c%c)",
                            ship->shipname, colours(ship), sterncolour(ship));
                        l = strlen(buf);
                        buf += l;
                        len -= l;
                        fmt += 2;
                } else {
                        *buf++ = *fmt++;
                        len--;
                }
        }

        *buf = '\0';
}


void
makesignal(struct ship *from, const char *fmt, struct ship *ship, ...)
{
        char message[BUFSIZ];
        char format[BUFSIZ];
        va_list ap;

        va_start(ap, ship);
        fmtship(format, sizeof(format), fmt, ship);
        (void) vsnprintf(message, sizeof message, format, ap);
        va_end(ap);
        Writestr(W_SIGNAL, from, message);
}

void
makemsg(struct ship *from, const char *fmt, ...)
{
        char message[BUFSIZ];
        va_list ap;

        va_start(ap, fmt);
        (void) vsnprintf(message, sizeof message, fmt, ap);
        va_end(ap);
        Writestr(W_SIGNAL, from, message);
}

int
sync_exists(int game)
{
        char buf[sizeof sync_file];
        struct stat s;
        time_t t;

        (void) snprintf(buf, sizeof buf, SF, game);
        (void) time(&t);
        setegid(egid);
        if (stat(buf, &s) == -1) {
                setegid(gid);
                return 0;
        }
        if (s.st_mtime < t - 60*60*2) {         /* 2 hours */
                (void) unlink(buf);
                (void) snprintf(buf, sizeof buf, LF, game);
                (void) unlink(buf);
                setegid(gid);
                return 0;
        }
        setegid(gid);
        return 1;
}

int
sync_open(void)
{
        struct stat tmp;

        if (sync_fp != NULL)
                (void) fclose(sync_fp);
        (void) snprintf(sync_lock, sizeof sync_lock, LF, game);
        (void) snprintf(sync_file, sizeof sync_file, SF, game);
        setegid(egid);
        if (stat(sync_file, &tmp) == -1) {
                mode_t omask = umask(002);
                sync_fp = fopen(sync_file, "w+");
                (void) umask(omask);
        } else
                sync_fp = fopen(sync_file, "r+");
        setegid(gid);
        if (sync_fp == NULL)
                return -1;
        sync_seek = 0;
        return 0;
}

void
sync_close(int remove)
{
        if (sync_fp != 0)
                (void) fclose(sync_fp);
        if (remove) {
                setegid(egid);
                (void) unlink(sync_file);
                setegid(gid);
        }
}

void
Write(int type, struct ship *ship, long a, long b, long c, long d)
{
        (void) snprintf(sync_bp, sync_buf + sizeof sync_buf - sync_bp,
                "%d %d 0 %ld %ld %ld %ld\n",
               type, ship->file->index, a, b, c, d);
        while (*sync_bp++)
                ;
        sync_bp--;
        if (sync_bp >= &sync_buf[sizeof sync_buf])
                abort();
        (void) sync_update(type, ship, NULL, a, b, c, d);
}

void
Writestr(int type, struct ship *ship, const char *a)
{
        (void) snprintf(sync_bp, sync_buf + sizeof sync_buf - sync_bp,
                "%d %d 1 %s\n",
                type, ship->file->index, a);
        while (*sync_bp++)
                ;
        sync_bp--;
        if (sync_bp >= &sync_buf[sizeof sync_buf])
                abort();
        (void) sync_update(type, ship, a, 0, 0, 0, 0);
}

int
Sync(void)
{
        sig_t sighup, sigint;
        int n;
        int type, shipnum, isstr;
        char *astr;
        long a, b, c, d;
        char buf[80];
        char erred = 0;

        sighup = signal(SIGHUP, SIG_IGN);
        sigint = signal(SIGINT, SIG_IGN);
        for (n = TIMEOUT; --n >= 0;) {
#ifdef LOCK_EX
                if (flock(fileno(sync_fp), LOCK_EX|LOCK_NB) >= 0)
                        break;
                if (errno != EWOULDBLOCK)
                        return -1;
#else
                setegid(egid);
                if (link(sync_file, sync_lock) >= 0) {
                        setegid(gid);
                        break;
                }
                setegid(gid);
                if (errno != EEXIST)
                        return -1;
#endif
                sleep(1);
        }
        if (n <= 0)
                return -1;
        (void) fseek(sync_fp, sync_seek, SEEK_SET);
        for (;;) {
                switch (fscanf(sync_fp, "%d%d%d", &type, &shipnum, &isstr)) {
                case 3:
                        break;
                case EOF:
                        goto out;
                default:
                        goto bad;
                }
                if (shipnum < 0 || shipnum >= cc->vessels)
                        goto bad;
                if (isstr != 0 && isstr != 1)
                        goto bad;
                if (isstr) {
                        int ch;
                        char *p;

                        for (p = buf;;) {
                                ch = getc(sync_fp);
                                switch (ch) {
                                case '\n':
                                case EOF:
                                        break;
                                default:
                                        if (p < buf + sizeof buf)
                                                *p++ = ch;
                                        continue;
                                }
                                break;
                        }
                        *p = 0;
                        for (p = buf; *p == ' '; p++)
                                ;
                        astr = p;
                        a = b = c = d = 0;
                } else {
                        if (fscanf(sync_fp, "%ld%ld%ld%ld", &a, &b, &c, &d) != 4)
                                goto bad;
                        astr = NULL;
                }
                if (sync_update(type, SHIP(shipnum), astr, a, b, c, d) < 0)
                        goto bad;
        }
bad:
        erred++;
out:
        if (!erred && sync_bp != sync_buf) {
                (void) fseek(sync_fp, 0L, SEEK_END);
                (void) fwrite(sync_buf, sizeof *sync_buf, sync_bp - sync_buf,
                        sync_fp);
                (void) fflush(sync_fp);
                sync_bp = sync_buf;
        }
        sync_seek = ftell(sync_fp);
#ifdef LOCK_EX
        (void) flock(fileno(sync_fp), LOCK_UN);
#else
        setegid(egid);
        (void) unlink(sync_lock);
        setegid(gid);
#endif
        (void) signal(SIGHUP, sighup);
        (void) signal(SIGINT, sigint);
        return erred ? -1 : 0;
}

int
sync_update(int type, struct ship *ship, const char *astr, long a, long b,
    long c, long d)
{
        switch (type) {
        case W_DBP: {
                struct BP *p = &ship->file->DBP[a];
                p->turnsent = b;
                p->toship = SHIP(c);
                p->mensent = d;
                break;
                }
        case W_OBP: {
                struct BP *p = &ship->file->OBP[a];
                p->turnsent = b;
                p->toship = SHIP(c);
                p->mensent = d;
                break;
                }
        case W_FOUL: {
                struct snag *p = &ship->file->foul[a];
                if (SHIP(a)->file->dir == 0)
                        break;
                if (p->sn_count++ == 0)
                        p->sn_turn = turn;
                ship->file->nfoul++;
                break;
                }
        case W_GRAP: {
                struct snag *p = &ship->file->grap[a];
                if (SHIP(a)->file->dir == 0)
                        break;
                if (p->sn_count++ == 0)
                        p->sn_turn = turn;
                ship->file->ngrap++;
                break;
                }
        case W_UNFOUL: {
                struct snag *p = &ship->file->foul[a];
                if (p->sn_count > 0) {
                        if (b) {
                                ship->file->nfoul -= p->sn_count;
                                p->sn_count = 0;
                        } else {
                                ship->file->nfoul--;
                                p->sn_count--;
                        }
                }
                break;
                }
        case W_UNGRAP: {
                struct snag *p = &ship->file->grap[a];
                if (p->sn_count > 0) {
                        if (b) {
                                ship->file->ngrap -= p->sn_count;
                                p->sn_count = 0;
                        } else {
                                ship->file->ngrap--;
                                p->sn_count--;
                        }
                }
                break;
                }
        case W_SIGNAL:
                if (mode == MODE_PLAYER) {
                        if (nobells)
                                Signal("$$: %s", ship, astr);
                        else
                                Signal("\7$$: %s", ship, astr);
                }
                break;
        case W_CREW: {
                struct shipspecs *s = ship->specs;
                s->crew1 = a;
                s->crew2 = b;
                s->crew3 = c;
                break;
                }
        case W_CAPTAIN:
                (void) strlcpy(ship->file->captain, astr,
                        sizeof ship->file->captain);
                break;
        case W_CAPTURED:
                if (a < 0)
                        ship->file->captured = 0;
                else
                        ship->file->captured = SHIP(a);
                break;
        case W_CLASS:
                ship->specs->class = a;
                break;
        case W_DRIFT:
                ship->file->drift = a;
                break;
        case W_EXPLODE:
                if ((ship->file->explode = a) == 2)
                        ship->file->dir = 0;
                break;
        case W_FS:
                ship->file->FS = a;
                break;
        case W_GUNL: {
                struct shipspecs *s = ship->specs;
                s->gunL = a;
                s->carL = b;
                break;
                }
        case W_GUNR: {
                struct shipspecs *s = ship->specs;
                s->gunR = a;
                s->carR = b;
                break;
                }
        case W_HULL:
                ship->specs->hull = a;
                break;
        case W_MOVE:
                (void) strlcpy(ship->file->movebuf, astr,
                        sizeof ship->file->movebuf);
                break;
        case W_PCREW:
                ship->file->pcrew = a;
                break;
        case W_POINTS:
                ship->file->points = a;
                break;
        case W_QUAL:
                ship->specs->qual = a;
                break;
        case W_RIGG: {
                struct shipspecs *s = ship->specs;
                s->rig1 = a;
                s->rig2 = b;
                s->rig3 = c;
                s->rig4 = d;
                break;
                }
        case W_RIG1:
                ship->specs->rig1 = a;
                break;
        case W_RIG2:
                ship->specs->rig2 = a;
                break;
        case W_RIG3:
                ship->specs->rig3 = a;
                break;
        case W_RIG4:
                ship->specs->rig4 = a;
                break;
        case W_COL:
                ship->file->col = a;
                break;
        case W_DIR:
                ship->file->dir = a;
                break;
        case W_ROW:
                ship->file->row = a;
                break;
        case W_SINK:
                if ((ship->file->sink = a) == 2)
                        ship->file->dir = 0;
                break;
        case W_STRUCK:
                ship->file->struck = a;
                break;
        case W_TA:
                ship->specs->ta = a;
                break;
        case W_ALIVE:
                alive = 1;
                break;
        case W_TURN:
                turn = a;
                break;
        case W_WIND:
                winddir = a;
                windspeed = b;
                break;
        case W_BEGIN:
                (void) strlcpy(ship->file->captain, "begin",
                    sizeof ship->file->captain);
                people++;
                break;
        case W_END:
                *ship->file->captain = 0;
                ship->file->points = 0;
                people--;
                break;
        case W_DDEAD:
                hasdriver = 0;
                break;
        default:
                fprintf(stderr, "sync_update: unknown type %d\r\n", type);
                return -1;
        }
        return 0;
}