/*
 * Copyright 2002 Massachusetts Institute of Technology
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that both the above copyright notice and this
 * permission notice appear in all copies, that both the above
 * copyright notice and this permission notice appear in all
 * supporting documentation, and that the name of M.I.T. not be used
 * in advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.  M.I.T. makes
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied
 * warranty.
 *
 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
 * SHALL M.I.T. 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/statvfs.h>

#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include "un-namespace.h"

static int      sfs2svfs(const struct statfs *from, struct statvfs *to);

int
fstatvfs(int fd, struct statvfs *result)
{
        struct statfs sfs;
        int rv;
        long pcval;

        rv = _fstatfs(fd, &sfs);
        if (rv != 0)
                return (rv);

        rv = sfs2svfs(&sfs, result);
        if (rv != 0)
                return (rv);

        /*
         * Whether pathconf's -1 return means error or unlimited does not
         * make any difference in this best-effort implementation.
         */
        pcval = _fpathconf(fd, _PC_NAME_MAX);
        if (pcval == -1)
                result->f_namemax = ~0UL;
        else
                result->f_namemax = (unsigned long)pcval;
        return (0);
}

int
statvfs(const char * __restrict path, struct statvfs * __restrict result)
{
        struct statfs sfs;
        int rv;
        long pcval;

        rv = statfs(path, &sfs);
        if (rv != 0)
                return (rv);

        sfs2svfs(&sfs, result);

        /*
         * Whether pathconf's -1 return means error or unlimited does not
         * make any difference in this best-effort implementation.
         */
        pcval = pathconf(path, _PC_NAME_MAX);
        if (pcval == -1)
                result->f_namemax = ~0UL;
        else
                result->f_namemax = (unsigned long)pcval;
        return (0);
}

static int
sfs2svfs(const struct statfs *from, struct statvfs *to)
{
        static const struct statvfs zvfs;

        *to = zvfs;

        if (from->f_flags & MNT_RDONLY)
                to->f_flag |= ST_RDONLY;
        if (from->f_flags & MNT_NOSUID)
                to->f_flag |= ST_NOSUID;

        /* XXX should we clamp negative values? */
#define COPY(field) \
        do { \
                to->field = from->field; \
                if (from->field != to->field) { \
                        errno = EOVERFLOW; \
                        return (-1); \
                } \
        } while(0)

        COPY(f_bavail);
        COPY(f_bfree);
        COPY(f_blocks);
        COPY(f_ffree);
        COPY(f_files);
        to->f_bsize = from->f_iosize;
        to->f_frsize = from->f_bsize;
        to->f_favail = to->f_ffree;
        return (0);
}
                                                                 
#ifdef MAIN
#include <err.h>
#include <stdint.h>
#include <stdio.h>

int
main(int argc, char **argv)
{
        struct statvfs buf;

        if (statvfs(argv[1], &buf) < 0)
                err(1, "statvfs");

#define SHOW(field) \
        printf(#field ": %ju\n", (uintmax_t)buf.field)

        SHOW(f_bavail);
        SHOW(f_bfree);
        SHOW(f_blocks);
        SHOW(f_favail);
        SHOW(f_ffree);
        SHOW(f_files);
        SHOW(f_bsize);
        SHOW(f_frsize);
        SHOW(f_namemax);
        printf("f_flag: %lx\n", (unsigned long)buf.f_flag);

        return 0;
}

#endif /* MAIN */