/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1988, 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 "namespace.h"
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/stat.h>

#include <errno.h>
#include <fstab.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <vis.h>
#include "un-namespace.h"

static FILE *_fs_fp;
static struct fstab _fs_fstab;
static int LineNo = 0;
static char *path_fstab;
static char fstab_path[PATH_MAX];
static int fsp_set = 0;

static void error(int);
static void fixfsfile(void);
static int fstabscan(void);

void
setfstab(const char *file)
{

        if (file == NULL) {
                path_fstab = _PATH_FSTAB;
        } else {
                strncpy(fstab_path, file, PATH_MAX);
                fstab_path[PATH_MAX - 1] = '\0';
                path_fstab = fstab_path;
        }
        fsp_set = 1;

        return;
}

const char *
getfstab(void)
{

        if (fsp_set)
                return (path_fstab);
        else
                return (_PATH_FSTAB);
}

static void
fixfsfile(void)
{
        static char buf[sizeof(_PATH_DEV) + MNAMELEN];
        struct stat sb;
        struct statfs sf;

        if (_fs_fstab.fs_file != NULL && strcmp(_fs_fstab.fs_file, "/") != 0)
                return;
        if (statfs("/", &sf) != 0)
                return;
        if (sf.f_mntfromname[0] == '/')
                buf[0] = '\0';
        else
                strcpy(buf, _PATH_DEV);
        strcat(buf, sf.f_mntfromname);
        if (stat(buf, &sb) != 0 ||
            (!S_ISBLK(sb.st_mode) && !S_ISCHR(sb.st_mode)))
                return;
        _fs_fstab.fs_spec = buf;
}

static int
fstabscan(void)
{
        char *cp, *p;
#define MAXLINELENGTH   1024
        static char line[MAXLINELENGTH];
        char subline[MAXLINELENGTH];
        int typexx;

        for (;;) {

                if (!(p = fgets(line, sizeof(line), _fs_fp)))
                        return (0);
/* OLD_STYLE_FSTAB */
                ++LineNo;
                if (*line == '#' || *line == '\n')
                        continue;
                if (!strpbrk(p, " \t")) {
                        _fs_fstab.fs_spec = strsep(&p, ":\n");
                        _fs_fstab.fs_file = strsep(&p, ":\n");
                        fixfsfile();
                        _fs_fstab.fs_type = strsep(&p, ":\n");
                        if (_fs_fstab.fs_type) {
                                if (!strcmp(_fs_fstab.fs_type, FSTAB_XX))
                                        continue;
                                _fs_fstab.fs_mntops = _fs_fstab.fs_type;
                                _fs_fstab.fs_vfstype =
                                    strcmp(_fs_fstab.fs_type, FSTAB_SW) ?
                                    "ufs" : "swap";
                                if ((cp = strsep(&p, ":\n")) != NULL) {
                                        _fs_fstab.fs_freq = atoi(cp);
                                        if ((cp = strsep(&p, ":\n")) != NULL) {
                                                _fs_fstab.fs_passno = atoi(cp);
                                                return (1);
                                        }
                                }
                        }
                        goto bad;
                }
/* OLD_STYLE_FSTAB */
                while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
                        ;
                _fs_fstab.fs_spec = cp;
                if (_fs_fstab.fs_spec == NULL || *_fs_fstab.fs_spec == '#')
                        continue;
                if (strunvis(_fs_fstab.fs_spec, _fs_fstab.fs_spec) < 0)
                        goto bad;
                while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
                        ;
                _fs_fstab.fs_file = cp;
                if (_fs_fstab.fs_file == NULL)
                        goto bad;
                if (strunvis(_fs_fstab.fs_file, _fs_fstab.fs_file) < 0)
                        goto bad;
                fixfsfile();
                while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
                        ;
                _fs_fstab.fs_vfstype = cp;
                while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
                        ;
                _fs_fstab.fs_mntops = cp;
                if (_fs_fstab.fs_mntops == NULL)
                        goto bad;
                _fs_fstab.fs_freq = 0;
                _fs_fstab.fs_passno = 0;
                while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
                        ;
                if (cp != NULL) {
                        _fs_fstab.fs_freq = atoi(cp);
                        while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
                                ;
                        if (cp != NULL)
                                _fs_fstab.fs_passno = atoi(cp);
                }
                (void)strlcpy(subline, _fs_fstab.fs_mntops, sizeof(subline));
                p = subline;
                for (typexx = 0, cp = strsep(&p, ","); cp;
                     cp = strsep(&p, ",")) {
                        if (strlen(cp) != 2)
                                continue;
                        if (!strcmp(cp, FSTAB_RW)) {
                                _fs_fstab.fs_type = FSTAB_RW;
                                break;
                        }
                        if (!strcmp(cp, FSTAB_RQ)) {
                                _fs_fstab.fs_type = FSTAB_RQ;
                                break;
                        }
                        if (!strcmp(cp, FSTAB_RO)) {
                                _fs_fstab.fs_type = FSTAB_RO;
                                break;
                        }
                        if (!strcmp(cp, FSTAB_SW)) {
                                _fs_fstab.fs_type = FSTAB_SW;
                                break;
                        }
                        if (!strcmp(cp, FSTAB_XX)) {
                                _fs_fstab.fs_type = FSTAB_XX;
                                typexx++;
                                break;
                        }
                }
                if (typexx)
                        continue;
                if (cp != NULL)
                        return (1);

bad:            /* no way to distinguish between EOF and syntax error */
                error(EFTYPE);
        }
        /* NOTREACHED */
}

struct fstab *
getfsent(void)
{

        if ((!_fs_fp && !setfsent()) || !fstabscan())
                return (NULL);
        return (&_fs_fstab);
}

struct fstab *
getfsspec(const char *name)
{

        if (setfsent())
                while (fstabscan())
                        if (!strcmp(_fs_fstab.fs_spec, name))
                                return (&_fs_fstab);
        return (NULL);
}

struct fstab *
getfsfile(const char *name)
{

        if (setfsent())
                while (fstabscan())
                        if (!strcmp(_fs_fstab.fs_file, name))
                                return (&_fs_fstab);
        return (NULL);
}

int
setfsent(void)
{
        if (_fs_fp) {
                rewind(_fs_fp);
                LineNo = 0;
                return (1);
        }
        if (fsp_set == 0)
                setfstab(secure_getenv("PATH_FSTAB"));
        if ((_fs_fp = fopen(path_fstab, "re")) != NULL) {
                LineNo = 0;
                return (1);
        }
        error(errno);
        return (0);
}

void
endfsent(void)
{

        if (_fs_fp) {
                (void)fclose(_fs_fp);
                _fs_fp = NULL;
        }

        fsp_set = 0;
}

static void
error(int err)
{
        char *p;
        char num[30];

        (void)_write(STDERR_FILENO, "fstab: ", 7);
        (void)_write(STDERR_FILENO, path_fstab, strlen(path_fstab));
        (void)_write(STDERR_FILENO, ":", 1);
        sprintf(num, "%d: ", LineNo);
        (void)_write(STDERR_FILENO, num, strlen(num));
        p = strerror(err);
        (void)_write(STDERR_FILENO, p, strlen(p));
        (void)_write(STDERR_FILENO, "\n", 1);
}