/*      $OpenBSD: fstab.c,v 1.22 2016/03/17 23:48:42 mmcc Exp $ */
/*
 * 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 <sys/types.h>
#include <sys/uio.h>
#include <sys/stat.h>

#include <errno.h>
#include <limits.h>
#include <fstab.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static FILE *_fs_fp;
static struct fstab _fs_fstab;

static int fstabscan(void);

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

        for (;;) {
                if (!(cp = fgets(line, sizeof(line), _fs_fp)))
                        return(0);
/* OLD_STYLE_FSTAB */
                if (!strpbrk(cp, " \t")) {
                        _fs_fstab.fs_spec = strtok_r(cp, ":\n", &last);
                        if (!_fs_fstab.fs_spec || *_fs_fstab.fs_spec == '#')
                                continue;
                        _fs_fstab.fs_file = strtok_r(NULL, ":\n", &last);
                        _fs_fstab.fs_type = strtok_r(NULL, ":\n", &last);
                        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 = strtok_r(NULL, ":\n", &last))) {
                                        _fs_fstab.fs_freq = strtonum(cp, 0,
                                            INT_MAX, &errstr);
                                        if (errstr)
                                                goto bad;
                                        if ((cp = strtok_r(NULL,
                                            ":\n", &last))) {
                                                _fs_fstab.fs_passno =
                                                    strtonum(cp, 0, INT_MAX,
                                                    &errstr);
                                                if (errstr)
                                                        goto bad;
                                                return(1);
                                        }
                                }
                        }
                        goto bad;
                }
/* OLD_STYLE_FSTAB */
                _fs_fstab.fs_spec = strtok_r(cp, " \t\n", &last);
                if (!_fs_fstab.fs_spec || *_fs_fstab.fs_spec == '#')
                        continue;
                _fs_fstab.fs_file = strtok_r(NULL, " \t\n", &last);
                _fs_fstab.fs_vfstype = strtok_r(NULL, " \t\n", &last);
                _fs_fstab.fs_mntops = strtok_r(NULL, " \t\n", &last);
                if (_fs_fstab.fs_mntops == NULL)
                        goto bad;
                _fs_fstab.fs_freq = 0;
                _fs_fstab.fs_passno = 0;
                if ((cp = strtok_r(NULL, " \t\n", &last)) != NULL) {
                        _fs_fstab.fs_freq = strtonum(cp, 0, INT_MAX, &errstr);
                        if (errstr)
                                goto bad;
                        if ((cp = strtok_r(NULL, " \t\n", &last)) != NULL) {
                                _fs_fstab.fs_passno = strtonum(cp, 0, INT_MAX,
                                    &errstr);
                                if (errstr)
                                        goto bad;
                        }
                }
                strlcpy(subline, _fs_fstab.fs_mntops, sizeof subline);
                for (typexx = 0, cp = strtok_r(subline, ",", &last); cp;
                     cp = strtok_r(NULL, ",", &last)) {
                        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:            /* We silently ignore all bogus lines */
                ;
        }
}

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)
{
        struct stat sbuf;

        if (_fs_fp) {
                rewind(_fs_fp);
                return(1);
        }

        if (stat(_PATH_FSTAB, &sbuf) != 0)
                goto fail;
        if ((sbuf.st_size == 0) || ((sbuf.st_mode & S_IFMT) != S_IFREG)) {
                errno = EFTYPE;
                goto fail;
        }

        if ((_fs_fp = fopen(_PATH_FSTAB, "re")))
                return(1);

fail:
        return(0);
}
DEF_WEAK(setfsent);

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