/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1989, 1993, 1994
 *      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>
#define _WANT_MNTOPTNAMES
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/wait.h>

#include <ctype.h>

#include <errno.h>
#include <fstab.h>
#include <mntopts.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libutil.h>
#include <libxo/xo.h>

#include "extern.h"
#include "pathnames.h"

#define EXIT(a) {                       \
        xo_close_container("mount");    \
        if (xo_finish() < 0)                    \
                xo_err(EXIT_FAILURE, "stdout"); \
        exit(a);                        \
        }

/* `meta' options */
#define MOUNT_META_OPTION_FSTAB         "fstab"
#define MOUNT_META_OPTION_CURRENT       "current"

static int debug, fstab_style, verbose;

struct cpa {
        char    **a;
        ssize_t sz;
        int     c;
};

char   *catopt(char *, const char *);
int     hasopt(const char *, const char *);
int     ismounted(struct fstab *, struct statfs *, int);
int     isremountable(const char *);
int     allow_file_mount(const char *);
void    mangle(char *, struct cpa *);
char   *update_options(char *, char *, int);
int     mountfs(const char *, const char *, const char *,
                        int, const char *, const char *);
void    remopt(char *, const char *);
void    prmount(struct statfs *);
void    putfsent(struct statfs *);
void    usage(void);
char   *flags2opts(int);

/* Map from mount options to printable formats. */
static struct mntoptnames optnames[] = {
        MNTOPT_NAMES
};

/*
 * List of VFS types that can be remounted without becoming mounted on top
 * of each other.
 * XXX Is this list correct?
 */
static const char *
remountable_fs_names[] = {
        "ufs", "ffs", "ext2fs",
        0
};

static const char userquotaeq[] = "userquota=";
static const char groupquotaeq[] = "groupquota=";

static char *mountprog = NULL;

static int
use_mountprog(const char *vfstype)
{
        /* XXX: We need to get away from implementing external mount
         *      programs for every filesystem, and move towards having
         *      each filesystem properly implement the nmount() system call.
         */
        unsigned int i;
        const char *fs[] = {
        "cd9660", "mfs", "msdosfs", "nfs",
        "nullfs", "smbfs", "udf", "unionfs",
        NULL
        };

        if (mountprog != NULL)
                return (1);

        for (i = 0; fs[i] != NULL; ++i) {
                if (strcmp(vfstype, fs[i]) == 0)
                        return (1);
        }

        return (0);
}

static int
exec_mountprog(const char *name, const char *execname, char *const argv[])
{
        pid_t pid;
        int status;

        switch (pid = fork()) {
        case -1:                                /* Error. */
                xo_warn("fork");
                EXIT(EXIT_FAILURE);
        case 0:                                 /* Child. */
                /* Go find an executable. */
                execvP(execname, _PATH_SYSPATH, argv);
                if (errno == ENOENT) {
                        xo_warn("exec %s not found", execname);
                        if (execname[0] != '/') {
                                xo_warnx("in path: %s", _PATH_SYSPATH);
                        }
                }
                EXIT(EXIT_FAILURE);
        default:                                /* Parent. */
                if (waitpid(pid, &status, 0) < 0) {
                        xo_warn("waitpid");
                        return (1);
                }

                if (WIFEXITED(status)) {
                        if (WEXITSTATUS(status) != 0)
                                return (WEXITSTATUS(status));
                } else if (WIFSIGNALED(status)) {
                        xo_warnx("%s: %s", name, sys_siglist[WTERMSIG(status)]);
                        return (1);
                }
                break;
        }

        return (0);
}

static int
specified_ro(const char *arg)
{
        char *optbuf, *opt;
        int ret = 0;

        optbuf = strdup(arg);
        if (optbuf == NULL)
                 xo_err(1, "strdup failed");

        for (opt = optbuf; (opt = strtok(opt, ",")) != NULL; opt = NULL) {
                if (strcmp(opt, "ro") == 0) {
                        ret = 1;
                        break;
                }
        }
        free(optbuf);
        return (ret);
}

static void
restart_mountd(void)
{

        pidfile_signal(_PATH_MOUNTDPID, SIGHUP, NULL);
}

int
main(int argc, char *argv[])
{
        const char *mntfromname, **vfslist, *vfstype;
        struct fstab *fs;
        struct statfs *mntbuf;
        int all, ch, i, init_flags, late, failok, mntsize, rval, have_fstab, ro;
        int onlylate;
        char *cp, *ep, *options;

        all = init_flags = late = onlylate = 0;
        ro = 0;
        options = NULL;
        vfslist = NULL;
        vfstype = "ufs";

        argc = xo_parse_args(argc, argv);
        if (argc < 0)
                exit(EXIT_FAILURE);
        xo_open_container("mount");

        while ((ch = getopt(argc, argv, "adF:fLlno:prt:uvw")) != -1)
                switch (ch) {
                case 'a':
                        all = 1;
                        break;
                case 'd':
                        debug = 1;
                        break;
                case 'F':
                        setfstab(optarg);
                        break;
                case 'f':
                        init_flags |= MNT_FORCE;
                        break;
                case 'L':
                        onlylate = 1;
                        late = 1;
                        break;
                case 'l':
                        late = 1;
                        break;
                case 'n':
                        /* For compatibility with the Linux version of mount. */
                        break;
                case 'o':
                        if (*optarg) {
                                options = catopt(options, optarg);
                                if (specified_ro(optarg))
                                        ro = 1;
                        }
                        break;
                case 'p':
                        fstab_style = 1;
                        verbose = 1;
                        break;
                case 'r':
                        options = catopt(options, "ro");
                        ro = 1;
                        break;
                case 't':
                        if (vfslist != NULL)
                                xo_errx(1, "only one -t option may be specified");
                        vfslist = makevfslist(optarg);
                        vfstype = optarg;
                        break;
                case 'u':
                        init_flags |= MNT_UPDATE;
                        break;
                case 'v':
                        verbose = 1;
                        break;
                case 'w':
                        options = catopt(options, "noro");
                        break;
                case '?':
                default:
                        usage();
                        /* NOTREACHED */
                }
        argc -= optind;
        argv += optind;

#define BADTYPE(type)                                                   \
        (strcmp(type, FSTAB_RO) &&                                      \
            strcmp(type, FSTAB_RW) && strcmp(type, FSTAB_RQ))

        if ((init_flags & MNT_UPDATE) && (ro == 0))
                options = catopt(options, "noro");

        rval = EXIT_SUCCESS;
        switch (argc) {
        case 0:
                if ((mntsize = getmntinfo(&mntbuf,
                     verbose ? MNT_WAIT : MNT_NOWAIT)) == 0)
                        xo_err(1, "getmntinfo");
                if (all) {
                        while ((fs = getfsent()) != NULL) {
                                if (BADTYPE(fs->fs_type))
                                        continue;
                                if (checkvfsname(fs->fs_vfstype, vfslist))
                                        continue;
                                if (hasopt(fs->fs_mntops, "noauto"))
                                        continue;
                                if (!hasopt(fs->fs_mntops, "late") && onlylate)
                                        continue;
                                if (hasopt(fs->fs_mntops, "late") && !late)
                                        continue;
                                if (hasopt(fs->fs_mntops, "failok"))
                                        failok = 1;
                                else
                                        failok = 0;
                                if (!(init_flags & MNT_UPDATE) &&
                                    !hasopt(fs->fs_mntops, "update") &&
                                    ismounted(fs, mntbuf, mntsize))
                                        continue;
                                options = update_options(options, fs->fs_mntops,
                                    mntbuf->f_flags);
                                if (mountfs(fs->fs_vfstype, fs->fs_spec,
                                    fs->fs_file, init_flags, options,
                                    fs->fs_mntops) && !failok)
                                        rval = EXIT_FAILURE;
                        }
                } else if (fstab_style) {
                        xo_open_list("fstab");
                        for (i = 0; i < mntsize; i++) {
                                if (checkvfsname(mntbuf[i].f_fstypename, vfslist))
                                        continue;
                                xo_open_instance("fstab");
                                putfsent(&mntbuf[i]);
                                xo_close_instance("fstab");
                        }
                        xo_close_list("fstab");
                } else {
                        xo_open_list("mounted");
                        for (i = 0; i < mntsize; i++) {
                                if (checkvfsname(mntbuf[i].f_fstypename,
                                    vfslist))
                                        continue;
                                if (!verbose &&
                                    (mntbuf[i].f_flags & MNT_IGNORE) != 0)
                                        continue;
                                xo_open_instance("mounted");
                                prmount(&mntbuf[i]);
                                xo_close_instance("mounted");
                        }
                        xo_close_list("mounted");
                }
                EXIT(rval);
        case 1:
                if (vfslist != NULL)
                        usage();

                rmslashes(*argv, *argv);
                if (init_flags & MNT_UPDATE) {
                        mntfromname = NULL;
                        have_fstab = 0;
                        if ((mntbuf = getmntpoint(*argv)) == NULL)
                                xo_errx(1, "not currently mounted %s", *argv);
                        /*
                         * Only get the mntflags from fstab if both mntpoint
                         * and mntspec are identical. Also handle the special
                         * case where just '/' is mounted and 'spec' is not
                         * identical with the one from fstab ('/dev' is missing
                         * in the spec-string at boot-time).
                         */
                        if ((fs = getfsfile(mntbuf->f_mntonname)) != NULL) {
                                if (strcmp(fs->fs_spec,
                                    mntbuf->f_mntfromname) == 0 &&
                                    strcmp(fs->fs_file,
                                    mntbuf->f_mntonname) == 0) {
                                        have_fstab = 1;
                                        mntfromname = mntbuf->f_mntfromname;
                                } else if (argv[0][0] == '/' &&
                                    argv[0][1] == '\0' &&
                                    strcmp(fs->fs_vfstype,
                                    mntbuf->f_fstypename) == 0) {
                                        fs = getfsfile("/");
                                        have_fstab = 1;
                                        mntfromname = fs->fs_spec;
                                }
                        }
                        if (have_fstab) {
                                options = update_options(options, fs->fs_mntops,
                                    mntbuf->f_flags);
                        } else {
                                mntfromname = mntbuf->f_mntfromname;
                                options = update_options(options, NULL,
                                    mntbuf->f_flags);
                        }
                        rval = mountfs(mntbuf->f_fstypename, mntfromname,
                            mntbuf->f_mntonname, init_flags, options, 0);
                        break;
                }
                if ((fs = getfsfile(*argv)) == NULL &&
                    (fs = getfsspec(*argv)) == NULL)
                        xo_errx(1, "%s: unknown special file or file system",
                            *argv);
                if (BADTYPE(fs->fs_type))
                        xo_errx(1, "%s has unknown file system type",
                            *argv);
                rval = mountfs(fs->fs_vfstype, fs->fs_spec, fs->fs_file,
                    init_flags, options, fs->fs_mntops);
                break;
        case 2:
                /*
                 * If -t flag has not been specified, the path cannot be
                 * found, spec contains either a ':' or a '@', then assume
                 * that an NFS file system is being specified ala Sun.
                 * Check if the hostname contains only allowed characters
                 * to reduce false positives.  IPv6 addresses containing
                 * ':' will be correctly parsed only if the separator is '@'.
                 * The definition of a valid hostname is taken from RFC 1034.
                 */
                if (vfslist == NULL && ((ep = strchr(argv[0], '@')) != NULL ||
                    (ep = strchr(argv[0], ':')) != NULL)) {
                        if (*ep == '@') {
                                cp = ep + 1;
                                ep = cp + strlen(cp);
                        } else
                                cp = argv[0];
                        while (cp != ep) {
                                if (!isdigit(*cp) && !isalpha(*cp) &&
                                    *cp != '.' && *cp != '-' && *cp != ':')
                                        break;
                                cp++;
                        }
                        if (cp == ep)
                                vfstype = "nfs";
                }
                rval = mountfs(vfstype,
                    argv[0], argv[1], init_flags, options, NULL);
                break;
        default:
                usage();
                /* NOTREACHED */
        }

        /*
         * If the mount was successfully, and done by root, tell mountd the
         * good news.
         */
        if (rval == EXIT_SUCCESS && getuid() == 0)
                restart_mountd();

        EXIT(rval);
}

int
ismounted(struct fstab *fs, struct statfs *mntbuf, int mntsize)
{
        char realfsfile[PATH_MAX];
        int i;

        if (fs->fs_file[0] == '/' && fs->fs_file[1] == '\0')
                /* the root file system can always be remounted */
                return (0);

        /* The user may have specified a symlink in fstab, resolve the path */
        if (realpath(fs->fs_file, realfsfile) == NULL) {
                /* Cannot resolve the path, use original one */
                strlcpy(realfsfile, fs->fs_file, sizeof(realfsfile));
        }

        /* 
         * Consider the filesystem to be mounted if:
         * It has the same mountpoint as a mounted filesystem, and
         * It has the same type as that same mounted filesystem, and
         * It has the same device name as that same mounted filesystem, OR
         *     It is a nonremountable filesystem
         */
        for (i = mntsize - 1; i >= 0; --i)
                if (strcmp(realfsfile, mntbuf[i].f_mntonname) == 0 &&
                    strcmp(fs->fs_vfstype, mntbuf[i].f_fstypename) == 0 && 
                    (!isremountable(fs->fs_vfstype) ||
                     (strcmp(fs->fs_spec, mntbuf[i].f_mntfromname) == 0)))
                        return (1);
        return (0);
}

int
isremountable(const char *vfsname)
{
        const char **cp;

        for (cp = remountable_fs_names; *cp; cp++)
                if (strcmp(*cp, vfsname) == 0)
                        return (1);
        return (0);
}

int
allow_file_mount(const char *vfsname)
{

        if (strcmp(vfsname, "nullfs") == 0)
                return (1);
        return (0);
}

int
hasopt(const char *mntopts, const char *option)
{
        int negative, found;
        char *opt, *optbuf;

        if (option[0] == 'n' && option[1] == 'o') {
                negative = 1;
                option += 2;
        } else
                negative = 0;
        optbuf = strdup(mntopts);
        found = 0;
        for (opt = optbuf; (opt = strtok(opt, ",")) != NULL; opt = NULL) {
                if (opt[0] == 'n' && opt[1] == 'o') {
                        if (!strcasecmp(opt + 2, option))
                                found = negative;
                } else if (!strcasecmp(opt, option))
                        found = !negative;
        }
        free(optbuf);
        return (found);
}

static void
append_arg(struct cpa *sa, char *arg)
{
        if (sa->c + 1 == sa->sz) {
                sa->sz = sa->sz == 0 ? 8 : sa->sz * 2;
                sa->a = realloc(sa->a, sizeof(*sa->a) * sa->sz);
                if (sa->a == NULL)
                        xo_errx(1, "realloc failed");
        }
        sa->a[++sa->c] = arg;
}

int
mountfs(const char *vfstype, const char *spec, const char *name, int flags,
        const char *options, const char *mntopts)
{
        struct statfs sf;
        int i, ret;
        char *optbuf, execname[PATH_MAX], mntpath[PATH_MAX];
        static struct cpa mnt_argv;

        /* resolve the mountpoint with realpath(3) */
        if (allow_file_mount(vfstype)) {
                if (checkpath_allow_file(name, mntpath) != 0) {
                        xo_warn("%s", mntpath);
                        return (1);
                }
        } else {
                if (checkpath(name, mntpath) != 0) {
                        xo_warn("%s", mntpath);
                        return (1);
                }
        }
        name = mntpath;

        if (mntopts == NULL)
                mntopts = "";
        optbuf = catopt(strdup(mntopts), options);

        if (strcmp(name, "/") == 0)
                flags |= MNT_UPDATE;
        if (flags & MNT_FORCE)
                optbuf = catopt(optbuf, "force");
        if (flags & MNT_RDONLY)
                optbuf = catopt(optbuf, "ro");
        /*
         * XXX
         * The mount_mfs (newfs) command uses -o to select the
         * optimization mode.  We don't pass the default "-o rw"
         * for that reason.
         */
        if (flags & MNT_UPDATE)
                optbuf = catopt(optbuf, "update");

        /* Compatibility glue. */
        if (strcmp(vfstype, "msdos") == 0)
                vfstype = "msdosfs";

        /* Construct the name of the appropriate mount command */
        (void)snprintf(execname, sizeof(execname), "mount_%s", vfstype);

        mnt_argv.c = -1;
        append_arg(&mnt_argv, execname);
        mangle(optbuf, &mnt_argv);
        if (mountprog != NULL)
                strlcpy(execname, mountprog, sizeof(execname));

        append_arg(&mnt_argv, strdup(spec));
        append_arg(&mnt_argv, strdup(name));
        append_arg(&mnt_argv, NULL);

        if (debug) {
                if (use_mountprog(vfstype))
                        xo_emit("{Lwc:exec}{:execname/%s}", execname);
                else
                        xo_emit("{:execname/mount}{P: }{l:opts/-t}{P: }{l:opts/%s}", vfstype);
                for (i = 1; i < mnt_argv.c; i++)
                        xo_emit("{P: }{l:opts}", mnt_argv.a[i]);
                xo_emit("\n");
                free(optbuf);
                free(mountprog);
                mountprog = NULL;
                return (0);
        }

        if (use_mountprog(vfstype)) {
                ret = exec_mountprog(name, execname, mnt_argv.a);
        } else {
                ret = mount_fs(vfstype, mnt_argv.c, mnt_argv.a);
        }

        free(optbuf);
        free(mountprog);
        mountprog = NULL;

        if (verbose) {
                if (statfs(name, &sf) < 0) {
                        xo_warn("statfs %s", name);
                        return (1);
                }
                if (fstab_style) {
                        xo_open_list("fstab");
                        xo_open_instance("fstab");
                        putfsent(&sf);
                        xo_close_instance("fstab");
                        xo_close_list("fstab");
                } else {
                        xo_open_list("mounted");
                        xo_open_instance("mounted");
                        prmount(&sf);
                        xo_close_instance("mounted");
                        xo_close_list("mounted");
                }
        }

        return (ret);
}

void
prmount(struct statfs *sfp)
{
        uint64_t flags;
        unsigned int i;
        struct mntoptnames *o;
        struct passwd *pw;
        char *fsidbuf;

        xo_emit("{:special/%hs}{L: on }{:node/%hs}{L: (}{:fstype}", sfp->f_mntfromname,
            sfp->f_mntonname, sfp->f_fstypename);

        flags = sfp->f_flags & MNT_VISFLAGMASK;
        for (o = optnames; flags != 0 && o->o_opt != 0; o++)
                if (flags & o->o_opt) {
                        xo_emit("{D:, }{l:opts}", o->o_name);
                        flags &= ~o->o_opt;
                }
        /*
         * Inform when file system is mounted by an unprivileged user
         * or privileged non-root user.
         */
        if ((flags & MNT_USER) != 0 || sfp->f_owner != 0) {
                xo_emit("{D:, }{L:mounted by }");
                if ((pw = getpwuid(sfp->f_owner)) != NULL)
                        xo_emit("{:mounter/%hs}", pw->pw_name);
                else
                        xo_emit("{:mounter/%hs}", sfp->f_owner);
        }
        if (verbose) {
                if (sfp->f_syncwrites != 0 || sfp->f_asyncwrites != 0) {
                        xo_open_container("writes");
                        xo_emit("{D:, }{Lwc:writes}{Lw:sync}{w:sync/%ju}{Lw:async}{:async/%ju}",
                            (uintmax_t)sfp->f_syncwrites,
                            (uintmax_t)sfp->f_asyncwrites);
                        xo_close_container("writes");
                }
                if (sfp->f_syncreads != 0 || sfp->f_asyncreads != 0) {
                        xo_open_container("reads");
                        xo_emit("{D:, }{Lwc:reads}{Lw:sync}{w:sync/%ju}{Lw:async}{:async/%ju}",
                            (uintmax_t)sfp->f_syncreads,
                            (uintmax_t)sfp->f_asyncreads);
                        xo_close_container("reads");
                }
                if (sfp->f_fsid.val[0] != 0 || sfp->f_fsid.val[1] != 0) {
                        fsidbuf = malloc(sizeof(sfp->f_fsid) * 2 + 1);
                        if (fsidbuf == NULL)
                                xo_errx(1, "malloc failed");
                        for (i = 0; i < sizeof(sfp->f_fsid); i++)
                                sprintf(&fsidbuf[i * 2], "%02x",
                                    ((u_char *)&sfp->f_fsid)[i]);
                        fsidbuf[i * 2] = '\0';
                        xo_emit("{D:, }{Lw:fsid}{:fsid}", fsidbuf);
                        free(fsidbuf);
                }
                if (sfp->f_nvnodelistsize != 0) {
                        xo_open_container("vnodes");
                        xo_emit("{D:, }{Lwc:vnodes}{Lw:count}{w:count/%ju}",
                            (uintmax_t)sfp->f_nvnodelistsize);
                        xo_close_container("vnodes");
                }
        }
        xo_emit("{D:)}\n");
}

char *
catopt(char *s0, const char *s1)
{
        char *cp;

        if (s1 == NULL || *s1 == '\0')
                return (s0);

        if (s0 && *s0) {
                if (asprintf(&cp, "%s,%s", s0, s1) == -1)
                        xo_errx(1, "asprintf failed");
        } else
                cp = strdup(s1);

        if (s0)
                free(s0);
        return (cp);
}

void
mangle(char *options, struct cpa *a)
{
        char *p, *s, *val;

        for (s = options; (p = strsep(&s, ",")) != NULL;)
                if (*p != '\0') {
                        if (strcmp(p, "noauto") == 0) {
                                /*
                                 * Do not pass noauto option to nmount().
                                 * or external mount program.  noauto is
                                 * only used to prevent mounting a filesystem
                                 * when 'mount -a' is specified, and is
                                 * not a real mount option.
                                 */
                                continue;
                        } else if (strcmp(p, "late") == 0) {
                                /*
                                 * "late" is used to prevent certain file
                                 * systems from being mounted before late
                                 * in the boot cycle; for instance,
                                 * loopback NFS mounts can't be mounted
                                 * before mountd starts.
                                 */
                                continue;
                        } else if (strcmp(p, "failok") == 0) {
                                /*
                                 * "failok" is used to prevent certain file
                                 * systems from being causing the system to
                                 * drop into single user mode in the boot
                                 * cycle, and is not a real mount option.
                                 */
                                continue;
                        } else if (strncmp(p, "mountprog", 9) == 0) {
                                /*
                                 * "mountprog" is used to force the use of
                                 * userland mount programs.
                                 */
                                val = strchr(p, '=');
                                if (val != NULL) {
                                        ++val;
                                        if (*val != '\0')
                                                mountprog = strdup(val);
                                }

                                if (mountprog == NULL) {
                                        xo_errx(1, "Need value for -o mountprog");
                                }
                                continue;
                        } else if (strcmp(p, "userquota") == 0) {
                                continue;
                        } else if (strncmp(p, userquotaeq,
                            sizeof(userquotaeq) - 1) == 0) {
                                continue;
                        } else if (strcmp(p, "groupquota") == 0) {
                                continue;
                        } else if (strncmp(p, groupquotaeq,
                            sizeof(groupquotaeq) - 1) == 0) {
                                continue;
                        } else if (*p == '-') {
                                append_arg(a, p);
                                p = strchr(p, '=');
                                if (p != NULL) {
                                        *p = '\0';
                                        append_arg(a, p + 1);
                                }
                        } else {
                                append_arg(a, strdup("-o"));
                                append_arg(a, p);
                        }
                }
}


char *
update_options(char *opts, char *fstab, int curflags)
{
        char *o, *p;
        char *cur;
        char *expopt, *newopt, *tmpopt;

        if (opts == NULL)
                return (strdup(""));

        /* remove meta options from list */
        remopt(fstab, MOUNT_META_OPTION_FSTAB);
        remopt(fstab, MOUNT_META_OPTION_CURRENT);
        cur = flags2opts(curflags);

        /*
         * Expand all meta-options passed to us first.
         */
        expopt = NULL;
        for (p = opts; (o = strsep(&p, ",")) != NULL;) {
                if (strcmp(MOUNT_META_OPTION_FSTAB, o) == 0)
                        expopt = catopt(expopt, fstab);
                else if (strcmp(MOUNT_META_OPTION_CURRENT, o) == 0)
                        expopt = catopt(expopt, cur);
                else
                        expopt = catopt(expopt, o);
        }
        free(cur);
        free(opts);

        /*
         * Remove previous contradictory arguments. Given option "foo" we
         * remove all the "nofoo" options. Given "nofoo" we remove "nonofoo"
         * and "foo" - so we can deal with possible options like "notice".
         */
        newopt = NULL;
        for (p = expopt; (o = strsep(&p, ",")) != NULL;) {
                if ((tmpopt = malloc( strlen(o) + 2 + 1 )) == NULL)
                        xo_errx(1, "malloc failed");

                strcpy(tmpopt, "no");
                strcat(tmpopt, o);
                remopt(newopt, tmpopt);
                free(tmpopt);

                if (strncmp("no", o, 2) == 0)
                        remopt(newopt, o+2);

                newopt = catopt(newopt, o);
        }
        free(expopt);

        return (newopt);
}

void
remopt(char *string, const char *opt)
{
        char *o, *p, *r;

        if (string == NULL || *string == '\0' || opt == NULL || *opt == '\0')
                return;

        r = string;

        for (p = string; (o = strsep(&p, ",")) != NULL;) {
                if (strcmp(opt, o) != 0) {
                        if (*r == ',' && *o != '\0')
                                r++;
                        while ((*r++ = *o++) != '\0')
                            ;
                        *--r = ',';
                }
        }
        *r = '\0';
}

void
usage(void)
{

        xo_error("%s\n%s\n%s\n",
"usage: mount [-adflpruvw] [-F fstab] [-o options] [-t [no]type[,type ...]]",
"       mount [-dfpruvw] special | node",
"       mount [-dfpruvw] [-o options] [-t [no]type[,type ...]] special node");
        EXIT(EXIT_FAILURE);
}

void
putfsent(struct statfs *ent)
{
        struct fstab *fst;
        const char *mntfromname;
        char *opts, *rw;
        int l;

        mntfromname = ent->f_mntfromname;
        opts = NULL;
        /* flags2opts() doesn't return the "rw" option. */
        if ((ent->f_flags & MNT_RDONLY) != 0)
                rw = NULL;
        else
                rw = catopt(NULL, "rw");

        opts = flags2opts(ent->f_flags);
        opts = catopt(rw, opts);

        if (strncmp(mntfromname, "<below>:", 8) == 0 ||
            strncmp(mntfromname, "<above>:", 8) == 0) {
                mntfromname += 8;
        }

        l = strlen(mntfromname);
        xo_emit("{:device}{P:/%s}{P:/%s}{P:/%s}",
            mntfromname,
            l < 8 ? "\t" : "",
            l < 16 ? "\t" : "",
            l < 24 ? "\t" : " ");
        l = strlen(ent->f_mntonname);
        xo_emit("{:mntpoint}{P:/%s}{P:/%s}{P:/%s}",
            ent->f_mntonname,
            l < 8 ? "\t" : "",
            l < 16 ? "\t" : "",
            l < 24 ? "\t" : " ");
        xo_emit("{:fstype}{P:\t}", ent->f_fstypename);
        l = strlen(opts);
        xo_emit("{:opts}{P:/%s}", opts,
            l < 8 ? "\t" : " ");
        free(opts);

        if ((fst = getfsspec(mntfromname)))
                xo_emit("{P:\t}{n:dump/%u}{P: }{n:pass/%u}\n",
                    fst->fs_freq, fst->fs_passno);
        else if ((fst = getfsfile(ent->f_mntonname)))
                xo_emit("{P:\t}{n:dump/%u}{P: }{n:pass/%u}\n",
                    fst->fs_freq, fst->fs_passno);
        else if (strcmp(ent->f_fstypename, "ufs") == 0) {
                if (strcmp(ent->f_mntonname, "/") == 0)
                        xo_emit("{P:\t}{n:dump/1}{P: }{n:pass/1}\n");
                else
                        xo_emit("{P:\t}{n:dump/2}{P: }{n:pass/2}\n");
        } else
                xo_emit("{P:\t}{n:dump/0}{P: }{n:pass/0}\n");
}


char *
flags2opts(int flags)
{
        char *res;

        res = NULL;

        if (flags & MNT_RDONLY)         res = catopt(res, "ro");
        if (flags & MNT_SYNCHRONOUS)    res = catopt(res, "sync");
        if (flags & MNT_NOEXEC)         res = catopt(res, "noexec");
        if (flags & MNT_NOSUID)         res = catopt(res, "nosuid");
        if (flags & MNT_UNION)          res = catopt(res, "union");
        if (flags & MNT_ASYNC)          res = catopt(res, "async");
        if (flags & MNT_NOATIME)        res = catopt(res, "noatime");
        if (flags & MNT_NOCLUSTERR)     res = catopt(res, "noclusterr");
        if (flags & MNT_NOCLUSTERW)     res = catopt(res, "noclusterw");
        if (flags & MNT_NOSYMFOLLOW)    res = catopt(res, "nosymfollow");
        if (flags & MNT_SUIDDIR)        res = catopt(res, "suiddir");
        if (flags & MNT_MULTILABEL)     res = catopt(res, "multilabel");
        if (flags & MNT_ACLS)           res = catopt(res, "acls");
        if (flags & MNT_NFS4ACLS)       res = catopt(res, "nfsv4acls");
        if (flags & MNT_UNTRUSTED)      res = catopt(res, "untrusted");
        if (flags & MNT_NOCOVER)        res = catopt(res, "nocover");
        if (flags & MNT_EMPTYDIR)       res = catopt(res, "emptydir");

        return (res);
}