/*-
 * 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.
 */

#include <sys/param.h>
#include <sys/mtio.h>
#include <sys/socket.h>
#include <sys/time.h>

#include <ufs/ufs/dinode.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>

#include <protocols/dumprestore.h>

#include <ctype.h>
#include <netdb.h>
#include <pwd.h>
#include <stdio.h>
#include <limits.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "pathnames.h"
#include "dump.h"

#define TS_CLOSED       0
#define TS_OPEN         1

static  int rmtstate = TS_CLOSED;
static  int rmtape;
static  char *rmtpeer;

static  int okname(const char *);
static  int rmtcall(const char *, const char *);
static  void rmtconnaborted(int);
static  int rmtgetb(void);
static  void rmtgetconn(void);
static  void rmtgets(char *, int);
static  int rmtreply(const char *);

static  int errfd = -1;

int
rmthost(const char *host)
{

        rmtpeer = strdup(host);
        if (rmtpeer == NULL)
                return (0);
        signal(SIGPIPE, rmtconnaborted);
        rmtgetconn();
        if (rmtape < 0)
                return (0);
        return (1);
}

static void
rmtconnaborted(int sig __unused)
{
        msg("Lost connection to remote host.\n");
        if (errfd != -1) {
                fd_set r;
                struct timeval t;

                FD_ZERO(&r);
                FD_SET(errfd, &r);
                t.tv_sec = 0;
                t.tv_usec = 0;
                if (select(errfd + 1, &r, NULL, NULL, &t)) {
                        int i;
                        char buf[2048];

                        if ((i = read(errfd, buf, sizeof(buf) - 1)) > 0) {
                                buf[i] = '\0';
                                msg("on %s: %s%s", rmtpeer, buf,
                                        buf[i - 1] == '\n' ? "" : "\n");
                        }
                }
        }

        exit(X_ABORT);
}

void
rmtgetconn(void)
{
        char *cp;
        const char *rmt;
        static struct servent *sp = NULL;
        static struct passwd *pwd = NULL;
        char *tuser;
        int size;
        int throughput;
        int on;

        if (sp == NULL) {
                sp = getservbyname("shell", "tcp");
                if (sp == NULL) {
                        msg("shell/tcp: unknown service\n");
                        exit(X_STARTUP);
                }
                pwd = getpwuid(getuid());
                if (pwd == NULL) {
                        msg("who are you?\n");
                        exit(X_STARTUP);
                }
        }
        if ((cp = strchr(rmtpeer, '@')) != NULL) {
                tuser = rmtpeer;
                *cp = '\0';
                if (!okname(tuser))
                        exit(X_STARTUP);
                rmtpeer = ++cp;
        } else
                tuser = pwd->pw_name;
        if ((rmt = getenv("RMT")) == NULL)
                rmt = _PATH_RMT;
        msg("%s", "");
        rmtape = rcmd(&rmtpeer, (u_short)sp->s_port, pwd->pw_name,
                      tuser, rmt, &errfd);
        if (rmtape < 0) {
                msg("login to %s as %s failed.\n", rmtpeer, tuser);
                return;
        }
        (void)fprintf(stderr, "Connection to %s established.\n", rmtpeer);
        size = ntrec * TP_BSIZE;
        if (size > 60 * 1024)           /* XXX */
                size = 60 * 1024;
        /* Leave some space for rmt request/response protocol */
        size += 2 * 1024;
        while (size > TP_BSIZE &&
            setsockopt(rmtape, SOL_SOCKET, SO_SNDBUF, &size, sizeof (size)) < 0)
                    size -= TP_BSIZE;
        (void)setsockopt(rmtape, SOL_SOCKET, SO_RCVBUF, &size, sizeof (size));
        throughput = IPTOS_THROUGHPUT;
        if (setsockopt(rmtape, IPPROTO_IP, IP_TOS,
            &throughput, sizeof(throughput)) < 0)
                perror("IP_TOS:IPTOS_THROUGHPUT setsockopt");
        on = 1;
        if (setsockopt(rmtape, IPPROTO_TCP, TCP_NODELAY, &on, sizeof (on)) < 0)
                perror("TCP_NODELAY setsockopt");
}

static int
okname(const char *cp0)
{
        const char *cp;
        int c;

        for (cp = cp0; *cp; cp++) {
                c = *cp;
                if (!isascii(c) || !(isalnum(c) || c == '_' || c == '-')) {
                        msg("invalid user name %s\n", cp0);
                        return (0);
                }
        }
        return (1);
}

int
rmtopen(const char *tape, int mode)
{
        char buf[256];

        (void)snprintf(buf, sizeof (buf), "O%.226s\n%d\n", tape, mode);
        rmtstate = TS_OPEN;
        return (rmtcall(tape, buf));
}

void
rmtclose(void)
{

        if (rmtstate != TS_OPEN)
                return;
        rmtcall("close", "C\n");
        rmtstate = TS_CLOSED;
}

int
rmtread(char *buf, int count)
{
        char line[30];
        int n, i, cc;

        (void)snprintf(line, sizeof (line), "R%d\n", count);
        n = rmtcall("read", line);
        if (n < 0)
                /* rmtcall() properly sets errno for us on errors. */
                return (n);
        for (i = 0; i < n; i += cc) {
                cc = read(rmtape, buf+i, n - i);
                if (cc <= 0)
                        rmtconnaborted(0);
        }
        return (n);
}

int
rmtwrite(const char *buf, int count)
{
        char line[30];

        (void)snprintf(line, sizeof (line), "W%d\n", count);
        write(rmtape, line, strlen(line));
        write(rmtape, buf, count);
        return (rmtreply("write"));
}

void
rmtwrite0(int count)
{
        char line[30];

        (void)snprintf(line, sizeof (line), "W%d\n", count);
        write(rmtape, line, strlen(line));
}

void
rmtwrite1(const char *buf, int count)
{

        write(rmtape, buf, count);
}

int
rmtwrite2(void)
{

        return (rmtreply("write"));
}

int
rmtseek(int offset, int pos)    /* XXX off_t ? */
{
        char line[80];

        (void)snprintf(line, sizeof (line), "L%d\n%d\n", offset, pos);
        return (rmtcall("seek", line));
}

struct  mtget mts;

struct mtget *
rmtstatus(void)
{
        int i;
        char *cp;

        if (rmtstate != TS_OPEN)
                return (NULL);
        rmtcall("status", "S\n");
        for (i = 0, cp = (char *)&mts; i < sizeof(mts); i++)
                *cp++ = rmtgetb();
        return (&mts);
}

int
rmtioctl(int cmd, int count)
{
        char buf[256];

        if (count < 0)
                return (-1);
        (void)snprintf(buf, sizeof (buf), "I%d\n%d\n", cmd, count);
        return (rmtcall("ioctl", buf));
}

static int
rmtcall(const char *cmd, const char *buf)
{

        if (write(rmtape, buf, strlen(buf)) != strlen(buf))
                rmtconnaborted(0);
        return (rmtreply(cmd));
}

static int
rmtreply(const char *cmd)
{
        char *cp;
        char code[30], emsg[BUFSIZ];

        rmtgets(code, sizeof (code));
        if (*code == 'E' || *code == 'F') {
                rmtgets(emsg, sizeof (emsg));
                msg("%s: %s", cmd, emsg);
                errno = atoi(code + 1);
                if (*code == 'F')
                        rmtstate = TS_CLOSED;
                return (-1);
        }
        if (*code != 'A') {
                /* Kill trailing newline */
                cp = code + strlen(code);
                if (cp > code && *--cp == '\n')
                        *cp = '\0';

                msg("Protocol to remote tape server botched (code \"%s\").\n",
                    code);
                rmtconnaborted(0);
        }
        return (atoi(code + 1));
}

int
rmtgetb(void)
{
        char c;

        if (read(rmtape, &c, 1) != 1)
                rmtconnaborted(0);
        return (c);
}

/* Get a line (guaranteed to have a trailing newline). */
void
rmtgets(char *line, int len)
{
        char *cp = line;

        while (len > 1) {
                *cp = rmtgetb();
                if (*cp == '\n') {
                        cp[1] = '\0';
                        return;
                }
                cp++;
                len--;
        }
        *cp = '\0';
        msg("Protocol to remote tape server botched.\n");
        msg("(rmtgets got \"%s\").\n", line);
        rmtconnaborted(0);
}