/*      $NetBSD: fstab.c,v 1.31 2012/03/13 21:13:34 christos 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)fstab.c     8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: fstab.c,v 1.31 2012/03/13 21:13:34 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <sys/types.h>

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

#ifdef __weak_alias
__weak_alias(endfsent,_endfsent)
__weak_alias(getfsent,_getfsent)
__weak_alias(getfsfile,_getfsfile)
__weak_alias(getfsspec,_getfsspec)
__weak_alias(setfsent,_setfsent)
#endif

static FILE *_fs_fp;
static size_t _fs_lineno = 0;
static const char *_fs_file = _PATH_FSTAB;
static struct fstab _fs_fstab;

static char *nextfld(char **, const char *);
static int fstabscan(void);


static char *
nextfld(char **str, const char *sep)
{
        char *ret;

        _DIAGASSERT(str != NULL);
        _DIAGASSERT(sep != NULL);

        while ((ret = stresep(str, sep, '\\')) != NULL && *ret == '\0')
                continue;
        return ret;
}


static int
fstabscan(void)
{
        char *cp, *lp, *sp;
#define MAXLINELENGTH   1024
        static char line[MAXLINELENGTH];
        char subline[MAXLINELENGTH];
        static const char sep[] = ":\n";
        static const char ws[] = " \t\n";
        static const char *fstab_type[] = {
            FSTAB_RW, FSTAB_RQ, FSTAB_RO, FSTAB_SW, FSTAB_DP, FSTAB_XX, NULL 
        };

        (void)memset(&_fs_fstab, 0, sizeof(_fs_fstab));
        for (;;) {
                if (!(lp = fgets(line, (int)sizeof(line), _fs_fp)))
                        return 0;
                _fs_lineno++;
/* OLD_STYLE_FSTAB */
                if (!strpbrk(lp, " \t")) {
                        _fs_fstab.fs_spec = nextfld(&lp, sep);
                        if (!_fs_fstab.fs_spec || *_fs_fstab.fs_spec == '#')
                                continue;
                        _fs_fstab.fs_file = nextfld(&lp, sep);
                        _fs_fstab.fs_type = nextfld(&lp, sep);
                        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 =
                                    __UNCONST(
                                    strcmp(_fs_fstab.fs_type, FSTAB_SW) ?
                                    "ufs" : "swap");
                                if ((cp = nextfld(&lp, sep)) != NULL) {
                                        _fs_fstab.fs_freq = atoi(cp);
                                        if ((cp = nextfld(&lp, sep)) != NULL) {
                                                _fs_fstab.fs_passno = atoi(cp);
                                                return 1;
                                        }
                                }
                        }
                        goto bad;
                }
/* OLD_STYLE_FSTAB */
                _fs_fstab.fs_spec = nextfld(&lp, ws);
                if (!_fs_fstab.fs_spec || *_fs_fstab.fs_spec == '#')
                        continue;
                _fs_fstab.fs_file = nextfld(&lp, ws);
                _fs_fstab.fs_vfstype = nextfld(&lp, ws);
                _fs_fstab.fs_mntops = nextfld(&lp, ws);
                if (_fs_fstab.fs_mntops == NULL)
                        goto bad;
                _fs_fstab.fs_freq = 0;
                _fs_fstab.fs_passno = 0;
                if ((cp = nextfld(&lp, ws)) != NULL) {
                        _fs_fstab.fs_freq = atoi(cp);
                        if ((cp = nextfld(&lp, ws)) != NULL)
                                _fs_fstab.fs_passno = atoi(cp);
                }

                /* subline truncated iff line truncated */
                (void)strlcpy(subline, _fs_fstab.fs_mntops, sizeof(subline));
                sp = subline;

                while ((cp = nextfld(&sp, ",")) != NULL) {
                        const char **tp;

                        if (strlen(cp) != 2)
                                continue;

                        for (tp = fstab_type; *tp; tp++)
                                if (strcmp(cp, *tp) == 0) {
                                        _fs_fstab.fs_type = __UNCONST(*tp);
                                        break;
                                }
                        if (*tp)
                                break;
                }
                if (_fs_fstab.fs_type == NULL)
                        goto bad;
                if (strcmp(_fs_fstab.fs_type, FSTAB_XX) == 0)
                        continue;
                if (cp != NULL)
                        return 1;

bad:
                warnx("%s, %lu: Missing fields", _fs_file, (u_long)_fs_lineno);
        }
        /* NOTREACHED */
}

struct fstab *
getfsent(void)
{
        if ((!_fs_fp && !setfsent()) || !fstabscan())
                return NULL;
        return &_fs_fstab;
}

struct fstab *
getfsspec(const char *name)
{

        _DIAGASSERT(name != NULL);

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

struct fstab *
getfsfile(const char *name)
{

        _DIAGASSERT(name != NULL);

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

int
setfsent(void)
{
        _fs_lineno = 0;
        if (_fs_fp) {
                rewind(_fs_fp);
                return 1;
        }
        if ((_fs_fp = fopen(_PATH_FSTAB, "re")) == NULL) {
                warn("Cannot open `%s'", _PATH_FSTAB);
                return 0;
        }
        return 1;
}

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