/*      $NetBSD: rmt.c,v 1.17 2018/01/23 21:06:25 sevan 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/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1983, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)rmt.c       8.1 (Berkeley) 6/6/93";
#else
__RCSID("$NetBSD: rmt.c,v 1.17 2018/01/23 21:06:25 sevan Exp $");
#endif
#endif /* not lint */

/*
 * rmt
 */
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mtio.h>
#include <sys/socket.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int     tape = -1;

int     maxrecsize = -1;

#define SSIZE   64
char    device[SSIZE];
char    count[SSIZE], mode[SSIZE], pos[SSIZE], op[SSIZE];

char    resp[BUFSIZ];

FILE    *debug;
#define DEBUG(f)        if (debug) fprintf(debug, f)
#define DEBUG1(f,a)     if (debug) fprintf(debug, f, a)
#define DEBUG2(f,a1,a2) if (debug) fprintf(debug, f, a1, a2)

char    *checkbuf(char *, int);
void     error(int);
void     getstring(char *, size_t);

int
main(int argc, char *argv[])
{
        char *record = NULL;
        int rval;
        char c;
        int n, i, cc;

        argc--, argv++;
        if (argc > 0) {
                debug = fopen(*argv, "w");
                if (debug == 0)
                        exit(1);
                (void)setbuf(debug, (char *)0);
        }
top:
        errno = 0;
        rval = 0;
        if (read(STDIN_FILENO, &c, 1) != 1)
                exit(0);
        switch (c) {

        case 'O':
                if (tape >= 0)
                        (void) close(tape);
                getstring(device, sizeof(device));
                getstring(mode, sizeof(mode));
                DEBUG2("rmtd: O %s %s\n", device, mode);
                tape = open(device, atoi(mode),
                    S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
                if (tape < 0)
                        goto ioerror;
                goto respond;

        case 'C':
                DEBUG("rmtd: C\n");
                getstring(device, sizeof(device));      /* discard */
                if (close(tape) < 0)
                        goto ioerror;
                tape = -1;
                goto respond;

        case 'L':
                getstring(count, sizeof(count));
                getstring(pos, sizeof(pos));
                DEBUG2("rmtd: L %s %s\n", count, pos);
                rval = lseek(tape, (off_t)strtoll(count, NULL, 10), atoi(pos));
                if (rval < 0)
                        goto ioerror;
                goto respond;

        case 'W':
                getstring(count, sizeof(count));
                n = atoi(count);
                DEBUG1("rmtd: W %s\n", count);
                record = checkbuf(record, n);
                for (i = 0; i < n; i += cc) {
                        cc = read(STDIN_FILENO, &record[i], n - i);
                        if (cc <= 0) {
                                DEBUG("rmtd: premature eof\n");
                                exit(2);
                        }
                }
                rval = write(tape, record, n);
                if (rval < 0)
                        goto ioerror;
                goto respond;

        case 'R':
                getstring(count, sizeof(count));
                DEBUG1("rmtd: R %s\n", count);
                n = atoi(count);
                record = checkbuf(record, n);
                rval = read(tape, record, n);
                if (rval < 0)
                        goto ioerror;
                (void)snprintf(resp, sizeof(resp), "A%d\n", rval);
                (void)write(STDOUT_FILENO, resp, strlen(resp));
                (void)write(STDOUT_FILENO, record, rval);
                goto top;

        case 'I':
                getstring(op, sizeof(op));
                getstring(count, sizeof(count));
                DEBUG2("rmtd: I %s %s\n", op, count);
                {
                        struct mtop mtop;

                        mtop.mt_op = atoi(op);
                        mtop.mt_count = atoi(count);
                        if (ioctl(tape, MTIOCTOP, (char *)&mtop) < 0)
                                goto ioerror;
                        rval = mtop.mt_count;
                }
                goto respond;

        case 'S':               /* status */
                DEBUG("rmtd: S\n");
                {
                        struct mtget mtget;

                        if (ioctl(tape, MTIOCGET, (char *)&mtget) < 0)
                                goto ioerror;
                        rval = sizeof (mtget);
                        /* limit size to 'original' mtget size */
                        if (rval > 24)
                                rval = 24;
                        (void)snprintf(resp, sizeof(resp), "A%d\n", rval);
                        (void)write(STDOUT_FILENO, resp, strlen(resp));
                        (void)write(STDOUT_FILENO, (char *)&mtget, rval);
                        goto top;
                }

        default:
                DEBUG1("rmtd: garbage command %c\n", c);
                exit(3);
        }
respond:
        DEBUG1("rmtd: A %d\n", rval);
        (void)snprintf(resp, sizeof(resp), "A%d\n", rval);
        (void)write(STDOUT_FILENO, resp, strlen(resp));
        goto top;
ioerror:
        error(errno);
        goto top;
}

void
getstring(char *bp, size_t size)
{
        char *cp = bp;
        char *ep = bp + size - 1;

        do {
                if (read(STDIN_FILENO, cp, 1) != 1)
                        exit(0);
        } while (*cp != '\n' && ++cp < ep);
        *cp = '\0';
}

char *
checkbuf(char *record, int size)
{

        if (size <= maxrecsize)
                return (record);
        if (record != 0)
                free(record);
        record = malloc(size);
        if (record == 0) {
                DEBUG("rmtd: cannot allocate buffer space\n");
                exit(4);
        }
        maxrecsize = size;
        while (size > 1024 &&
            setsockopt(0, SOL_SOCKET, SO_RCVBUF, &size, sizeof (size)) < 0)
                size -= 1024;
        return (record);
}

void
error(int num)
{

        DEBUG2("rmtd: E %d (%s)\n", num, strerror(num));
        (void)snprintf(resp, sizeof(resp), "E%d\n%s\n", num, strerror(num));
        (void)write(STDOUT_FILENO, resp, strlen(resp));
}