hal/tools/hal-storage-mount.c

/***************************************************************************
 * CVSID: $Id$
 *
 * hal-storage-mount.c : Mount wrapper
 *
 * Copyright (C) 2006 David Zeuthen, <david@fubar.dk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 **************************************************************************/


#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include <glib/gstdio.h>
#ifdef __FreeBSD__
#include <fstab.h>
#include <sys/param.h>
#include <sys/ucred.h>
#include <sys/mount.h>
#include <limits.h>
#include <pwd.h>
#elif sun
#include <sys/mnttab.h>
#include <sys/vfstab.h>
#include <sys/wait.h>
#else
#include <mntent.h>
#endif
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <syslog.h>

#include <libhal.h>
#include <libhal-storage.h>
#ifdef HAVE_POLKIT
#include <libpolkit.h>
#endif

#include "hal-storage-shared.h"

#ifdef __FreeBSD__
#define MOUNT       "/sbin/mount"
#define MOUNT_OPTIONS   "noexec,nosuid"
#define MOUNT_TYPE_OPT  "-t"
#elif sun
#define MOUNT       "/sbin/mount"
#define MOUNT_OPTIONS   "nosuid"
#define MOUNT_TYPE_OPT  "-F"
#else
#define MOUNT       "/bin/mount"
#define MOUNT_OPTIONS   "noexec,nosuid,nodev"
#define MOUNT_TYPE_OPT  "-t"
#endif

static void
usage (void)
{
    fprintf (stderr, "This program should only be started by hald.\n");
    exit (1);
}

static void
permission_denied_volume_ignore (const char *device)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.Volume.PermissionDenied\n");
    fprintf (stderr, "Device has %s volume.ignore set to TRUE. Refusing to mount.\n", device);
    exit (1);
}

static void
permission_denied_etc_fstab (const char *device)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.Volume.PermissionDenied\n");
    fprintf (stderr, "Device %s is listed in /etc/fstab. Refusing to mount.\n", device);
    exit (1);
}

static void
already_mounted (const char *device)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.Volume.AlreadyMounted\n");
    fprintf (stderr, "Device %s is already mounted.\n", device);
    exit (1);
}

static void
invalid_mount_option (const char *option, const char *uid)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.Volume.InvalidMountOption\n");
    fprintf (stderr, "The option '%s' is not allowed for uid=%s\n", option, uid);
    exit (1);
}

static void
unknown_filesystem (const char *filesystem)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.Volume.UnknownFilesystemType\n");
    fprintf (stderr, "Unknown file system '%s'\n", filesystem);
    exit (1);
}

static void
invalid_mount_point (const char *mount_point)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.Volume.InvalidMountpoint\n");
    fprintf (stderr, "The mount point '%s' is invalid\n", mount_point);
    exit (1);
}

static void
mount_point_not_available (const char *mount_point)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.Volume.MountPointNotAvailable\n");
    fprintf (stderr, "The mount point '%s' is already occupied\n", mount_point);
    exit (1);
}


static void
cannot_remount (const char *device)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.Volume.CannotRemount\n");
    fprintf (stderr, "%s not mounted already\n", device);
    exit (1);
}

#ifdef HAVE_POLKIT
static void
permission_denied_privilege (const char *privilege, const char *uid)
{
    fprintf (stderr, "org.freedesktop.Hal.Device.PermissionDeniedByPolicy\n");
    fprintf (stderr, "%s refused uid %s\n", privilege, uid);
    exit (1);
}
#endif


/* borrowed from gtk/gtkfilesystemunix.c in GTK+ on 02/23/2006 */
static void
canonicalize_filename (gchar *filename)
{
    gchar *p, *q;
    gboolean last_was_slash = FALSE;

    p = filename;
    q = filename;

    while (*p)
    {
        if (*p == G_DIR_SEPARATOR)
        {
            if (!last_was_slash)
                *q++ = G_DIR_SEPARATOR;

            last_was_slash = TRUE;
        }
        else
        {
            if (last_was_slash && *p == '.')
            {
                if (*(p + 1) == G_DIR_SEPARATOR ||
                    *(p + 1) == '\0')
                {
                    if (*(p + 1) == '\0')
                        break;

                    p += 1;
                }
                else if (*(p + 1) == '.' &&
                     (*(p + 2) == G_DIR_SEPARATOR ||
                      *(p + 2) == '\0'))
                {
                    if (q > filename + 1)
                    {
                        q--;
                        while (q > filename + 1 &&
                               *(q - 1) != G_DIR_SEPARATOR)
                            q--;
                    }

                    if (*(p + 2) == '\0')
                        break;

                    p += 2;
                }
                else
                {
                    *q++ = *p;
                    last_was_slash = FALSE;
                }
            }
            else
            {
                *q++ = *p;
                last_was_slash = FALSE;
            }
        }

        p++;
    }

    if (q > filename + 1 && *(q - 1) == G_DIR_SEPARATOR)
        q--;

    *q = '\0';
}

static char *
resolve_symlink (const char *file)
{
    GError *error;
    char *dir;
    char *link;
    char *f;
    char *f1;

    f = g_strdup (file);

    while (g_file_test (f, G_FILE_TEST_IS_SYMLINK)) {
        link = g_file_read_link (f, &error);
        if (link == NULL) {
            g_warning ("Cannot resolve symlink %s: %s", f, error->message);
            g_error_free (error);
            g_free (f);
            f = NULL;
            goto out;
        }

        dir = g_path_get_dirname (f);
        f1 = g_strdup_printf ("%s/%s", dir, link);
        g_free (dir);
        g_free (link);
        g_free (f);
        f = f1;
    }

out:
    if (f != NULL)
        canonicalize_filename (f);
    return f;
}

static LibHalVolume *
volume_findby (LibHalContext *hal_ctx, const char *property, const char *value)
{
    int i;
    char **hal_udis;
    int num_hal_udis;
    LibHalVolume *result = NULL;
    char *found_udi = NULL;
    DBusError error;

    dbus_error_init (&error);
    if ((hal_udis = libhal_manager_find_device_string_match (hal_ctx, property,
                                 value, &num_hal_udis, &error)) == NULL) {
        LIBHAL_FREE_DBUS_ERROR (&error);
        goto out;
    }
    for (i = 0; i < num_hal_udis; i++) {
        char *udi;
        udi = hal_udis[i];
        if (libhal_device_query_capability (hal_ctx, udi, "volume", &error)) {
            found_udi = strdup (udi);
            break;
        }
    }

    libhal_free_string_array (hal_udis);

    if (found_udi != NULL)
        result = libhal_volume_from_udi (hal_ctx, found_udi);

    free (found_udi);
out:
    return result;
}

static void
bailout_if_in_fstab (LibHalContext *hal_ctx, const char *device, const char *label, const char *uuid)
{
    gpointer handle;
    char *entry;
    char *_mount_point;

    printf (" label '%s'  uuid '%s'\n", label ? label : "" , uuid ? uuid : "");

    /* check if /etc/fstab mentions this device... (with symlinks etc) */
    if (! fstab_open (&handle)) {
        printf ("cannot open /etc/fstab\n");
        unknown_error ("Cannot open /etc/fstab");
    }
    while ((entry = fstab_next (handle, &_mount_point)) != NULL) {
        char *resolved;

#ifdef DEBUG
        printf ("Looking at /etc/fstab entry '%s'\n", entry);
#endif
        if (label != NULL && g_str_has_prefix (entry, "LABEL=")) {
            if (strcmp (entry + 6, label) == 0) {
                gboolean skip_fstab_entry;

                skip_fstab_entry = FALSE;

                /* (heck, we also do the stuff below in gnome-mount) */

                /* OK, so what's if someone attaches an external disk with the label '/' and
                 * /etc/fstab has
                 *
                 *    LABEL=/    /    ext3    defaults    1 1
                 *
                 * in /etc/fstab as most Red Hat systems do? Bugger, this is a very common use
                 * case; suppose that you take the disk from your Fedora server and attaches it
                 * to your laptop. Bingo, you now have two disks with the label '/'. One must
                 * seriously wonder if using things like LABEL=/ for / is a good idea; just
                 * what happens if you boot in this configuration? (answer: the initrd gets
                 * it wrong most of the time.. sigh)
                 *
                 * To work around this, check if the listed entry in /etc/fstab is already mounted,
                 * if it is, then check if it's the same device_file as the given one...
                 */

                /* see if a volume is mounted at this mount point  */
                if (_mount_point != NULL) {
                    LibHalVolume *mounted_vol;

                    mounted_vol = volume_findby (hal_ctx, "volume.mount_point", _mount_point);
                    if (mounted_vol != NULL) {
                        const char *mounted_vol_device_file;

                        mounted_vol_device_file = libhal_volume_get_device_file (mounted_vol);
                        /* no need to resolve symlinks, hal uses the canonical device file */
                        if (mounted_vol_device_file != NULL &&
                            strcmp (mounted_vol_device_file, device) !=0) {
#ifdef DEBUG
                            printf ("Wanting to mount %s that has label %s, but /etc/fstab says LABEL=%s is to be mounted at mount point '%s'. However %s (that also has label %s), is already mounted at said mount point. So, skipping said /etc/fstab entry.\n",
                                   device, label, label, _mount_point, mounted_vol_device_file, _mount_point);
#endif
                            skip_fstab_entry = TRUE;
                        }
                        libhal_volume_free (mounted_vol);
                    }
                }

                if (!skip_fstab_entry) {
                    printf ("%s found in /etc/fstab. Not mounting.\n", entry);
                    permission_denied_etc_fstab (device);
                }
            }
        } else if (uuid != NULL && g_str_has_prefix (entry, "UUID=")) {
            if (strcmp (entry + 5, uuid) == 0) {
                printf ("%s found in /etc/fstab. Not mounting.\n", entry);
                permission_denied_etc_fstab (device);
            }
        } else {

            resolved = resolve_symlink (entry);
#ifdef DEBUG
            printf ("/etc/fstab: device %s -> %s \n", entry, resolved);
#endif
            if (strcmp (device, resolved) == 0) {
                printf ("%s (-> %s) found in /etc/fstab. Not mounting.\n", entry, resolved);
                permission_denied_etc_fstab (device);
            }

            g_free (resolved);
        }
    }
    fstab_close (handle);
}

static gboolean
device_is_mounted (const char *device, char **mount_point)
{
    gpointer handle;
    char *entry;
    gboolean ret;

    ret = FALSE;

    /* check if /proc/mounts mentions this device... (with symlinks etc) */
    if (! mtab_open (&handle)) {
        printf ("cannot open mount list\n");
        unknown_error ("Cannot open /etc/mtab or equivalent");
    }
    while (((entry = mtab_next (handle, mount_point)) != NULL) && (ret == FALSE)) {
        char *resolved;

        resolved = resolve_symlink (entry);
#ifdef DEBUG
        printf ("/proc/mounts: device %s -> %s \n", entry, resolved);
#endif
        if (strcmp (device, resolved) == 0) {
            printf ("%s (-> %s) found in mount list. Not mounting.\n", entry, resolved);
            ret = TRUE;
        }

        g_free (resolved);
    }
    mtab_close (handle);
    return ret;
}

/* maps volume_id fs types to the appropriate -t mount option */
static const char *
map_fstype (const char *fstype)
{
#ifdef __FreeBSD__
    if (! strcmp (fstype, "iso9660"))
        return "cd9660";
    else if (! strcmp (fstype, "ext2"))
        return "ext2fs";
    else if (! strcmp (fstype, "vfat"))
        return "msdosfs";
#elif sun
    if (! strcmp (fstype, "iso9660"))
        return "hsfs";
    else if (! strcmp (fstype, "vfat"))
        return "pcfs";
#endif

    return fstype;
}

static void
handle_mount (LibHalContext *hal_ctx,
#ifdef HAVE_POLKIT
          LibPolKitContext *pol_ctx,
#endif
          const char *udi,
          LibHalVolume *volume, LibHalDrive *drive, const char *device,
          const char *invoked_by_uid, const char *invoked_by_syscon_name,
          DBusConnection *system_bus)
{
    int i, j;
    DBusError error;
    char mount_point[256];
    char mount_fstype[256];
    char mount_options[1024];
    char **allowed_options;
    char **given_options;
    gboolean wants_to_change_uid;
    char *mount_dir;
    GError *err = NULL;
    char *sout = NULL;
    char *serr = NULL;
    int exit_status;
    char *args[10];
    int na;
    GString *mount_option_str;
    gboolean pol_is_fixed;
    gboolean pol_change_uid;
    char *privilege;
    gboolean is_remount;
#ifdef HAVE_POLKIT
    gboolean allowed_by_privilege;
    gboolean is_temporary_privilege;
#endif
    gboolean explicit_mount_point_given;
    const char *end;
#ifdef __FreeBSD__
    struct passwd *pw;
    uid_t calling_uid;
    gid_t calling_gid;
#endif
    const char *label;
    const char *uuid;
    const char *model;
    const char *drive_type;
#ifdef sun
    adt_export_data_t *adt_data;
    size_t adt_data_size;
    gboolean append_ro = FALSE;
    gboolean is_abs_path = FALSE;
    uid_t calling_uid;

    calling_uid = atol (invoked_by_uid);
#endif

#ifdef DEBUG
    printf ("device                           = %s\n", device);
    printf ("invoked by uid                   = %s\n", invoked_by_uid);
    printf ("invoked by system bus connection = %s\n", invoked_by_syscon_name);
#endif

    if (volume != NULL) {
        dbus_error_init (&error);
        if (libhal_device_get_property_bool (hal_ctx, udi, "volume.ignore", &error) ||
            dbus_error_is_set (&error)) {
            if (dbus_error_is_set (&error)) {
                LIBHAL_FREE_DBUS_ERROR (&error);
            }
            /*
             * When device allocation is enabled (bsmconv or TX), we
             * set volume.ignore on all volumes, but still want
             * Mount() to succeed when called from the euid=0
             * device allocation program.
             */
            if (atol (invoked_by_uid) != 0) {
                permission_denied_volume_ignore (device);
            }
        }

        label = libhal_volume_get_label (volume);
        uuid = libhal_volume_get_uuid (volume);
    } else {
        label = NULL;
        uuid = NULL;
    }

    bailout_if_in_fstab (hal_ctx, device, label, uuid);

    /* TODO: sanity check that what hal exports is correct (cf. Martin Pitt's email) */

    /* read from stdin */
    if (strlen (fgets (mount_point, sizeof (mount_point), stdin)) > 0)
        mount_point   [strlen (mount_point)   - 1] = '\0';
    if (strlen (fgets (mount_fstype, sizeof (mount_fstype), stdin)) > 0)
        mount_fstype  [strlen (mount_fstype)  - 1] = '\0';
    if (strlen (fgets (mount_options, sizeof (mount_options), stdin)) > 0)
        mount_options [strlen (mount_options) - 1] = '\0';
    /* validate that input from stdin is UTF-8 */
    if (!g_utf8_validate (mount_point, -1, &end))
        unknown_error ("Error validating mount_point as UTF-8");
    if (!g_utf8_validate (mount_fstype, -1, &end))
        unknown_error ("Error validating mount_fstype as UTF-8");
    if (!g_utf8_validate (mount_options, -1, &end))
        unknown_error ("Error validating mount_options as UTF-8");

#ifdef sun
    if (calling_uid != 0) {
#endif
    for (i = 0; mount_point[i] != '\0'; i++) {
        if (mount_point[i] == '\n' ||
            mount_point[i] == G_DIR_SEPARATOR) {
            unknown_error ("mount_point cannot contain the following characters: newline, G_DIR_SEPARATOR (usually /)");
        }
    }
#ifdef sun
    }
    is_abs_path = (mount_point[0] == G_DIR_SEPARATOR);
#endif

#ifdef DEBUG
    printf ("mount_point    = '%s'\n", mount_point);
    printf ("mount_fstype   = '%s'\n", mount_fstype);
    printf ("mount_options  = '%s'\n", mount_options);
#endif

    /* delete any trailing whitespace options from splitting the string */
    given_options = g_strsplit (mount_options, "\t", 0);
    for (i = g_strv_length (given_options) - 1; i >= 0; --i) {
        if (strlen (given_options[i]) > 0)
            break;
        given_options[i] = NULL;
    }

#ifdef sun
    /* for read-only media append 'ro' option if not already */
    append_ro = libhal_device_get_property_bool (hal_ctx, libhal_drive_get_udi(drive),
        "storage.removable.solaris.read_only", NULL);

    if (append_ro) {
        for (i = 0; i < (int) g_strv_length (given_options); i++) {
            if (strcmp (given_options[i], "ro") == 0) {
                append_ro = FALSE;
            }
        }
    }
#endif /* sun */

    /* is option 'remount' included? */
    is_remount = FALSE;
    for (i = 0; i < (int) g_strv_length (given_options); i++) {
        if (strcmp (given_options[i], "remount") == 0) {
            is_remount = TRUE;
        }
    }

    mount_dir = NULL;
    if (is_remount) {
        if (volume != NULL) {
            if (!libhal_volume_is_mounted (volume)) {
                cannot_remount (device);
            }
            mount_dir = g_strdup (libhal_volume_get_mount_point (volume));
        } else {
            if (!device_is_mounted (device, &mount_dir)) {
                cannot_remount (device);
            }
        }

        if (mount_dir == NULL) {
            unknown_error ("Cannot get mount_dir for remount even though volume is mounted!");
        }

    } else {
        if (volume != NULL) {
            if (libhal_volume_is_mounted (volume)) {
                already_mounted (device);
            }
        } else {
            if (device_is_mounted (device, NULL)) {
                already_mounted (device);
            }
        }
    }

    if (!is_remount) {
        /* figure out mount point if no mount point is given... */
        explicit_mount_point_given = FALSE;
        if (strlen (mount_point) == 0) {
            char *p;
            const char *label;

            if (volume != NULL)
                label = libhal_volume_get_label (volume);
            else
                label = NULL;

            model = libhal_drive_get_model (drive);
            drive_type = libhal_drive_get_type_textual (drive);

            if (label != NULL) {
                /* best - use label */
                g_strlcpy (mount_point, label, sizeof (mount_point));

            } else if ((model != NULL) && (strlen (model) > 0)) {
                g_strlcpy (mount_point, model, sizeof (mount_point));
            } else if ((drive_type != NULL) && (strlen (drive_type) > 0)) {
                g_strlcpy (mount_point, drive_type, sizeof (mount_point));
            } else {
                /* fallback - use "disk" */
                g_snprintf (mount_point, sizeof (mount_point), "disk");
            }

            /* sanitize computed mount point name, e.g. replace invalid chars with '-' */
            p = mount_point;
            while (TRUE) {
                p = g_utf8_strchr (mount_point, -1, G_DIR_SEPARATOR);
                if (p == NULL)
                    break;
                *p = '-';
            };

        } else {
            explicit_mount_point_given = TRUE;
        }

        /* check mount point name - only forbid separators */
#ifdef sun
        if (calling_uid != 0) {
#endif
        if (g_utf8_strchr (mount_point, -1, G_DIR_SEPARATOR) != NULL) {
            printf ("'%s' is an invalid mount point\n", mount_point);
            invalid_mount_point (mount_point);
        }
#ifdef sun
        }
#endif

        /* check if mount point is available - append number to mount point */
        i = 0;
        mount_dir = NULL;
        while (TRUE) {
            g_free (mount_dir);
#ifdef sun
            if (is_abs_path)
                mount_dir = g_strdup (mount_point);
            else
#endif
            if (i == 0)
                mount_dir = g_strdup_printf ("/media/%s", mount_point);
            else
                mount_dir = g_strdup_printf ("/media/%s-%d", mount_point, i);

#ifdef DEBUG
            printf ("trying dir %s\n", mount_dir);
#endif

            /* XXX should test for being a mount point */
            if (!g_file_test (mount_dir, G_FILE_TEST_EXISTS)) {
                break;
            }

            if (explicit_mount_point_given) {
                mount_point_not_available (mount_dir);
            }

            i++;
        }
    }

    dbus_error_init (&error);
    allowed_options = libhal_device_get_property_strlist (hal_ctx, udi, "volume.mount.valid_options", &error);
    if (dbus_error_is_set (&error)) {
        unknown_error ("Cannot get volume.mount.valid_options");
        dbus_error_free (&error);
    }

#ifdef DEBUG
    for (i = 0; given_options[i] != NULL; i++)
        printf ("given_options[%d] = '%s'\n", i, given_options[i]);
    for (i = 0; allowed_options[i] != NULL; i++)
        printf ("allowed_options[%d] = '%s'\n", i, allowed_options[i]);
#endif

    wants_to_change_uid = FALSE;

    /* check mount options */
    for (i = 0; given_options[i] != NULL; i++) {
        char *given = given_options[i];

        for (j = 0; allowed_options[j] != NULL; j++) {
            char *allow = allowed_options[j];
            int allow_len = strlen (allow);

            if (strcmp (given, allow) == 0) {
                goto option_ok;
            }

            if ((allow[allow_len - 1] == '=') &&
                (strncmp (given, allow, allow_len) == 0) &&
                (int) strlen (given) > allow_len) {

                /* option matched allowed ending in '=', e.g.
                 * given == "umask=foobar" and allowed == "umask="
                 */
                if (strcmp (allow, "uid=") == 0) {
                    uid_t uid;
                    char *endp;
                    /* check for uid=, it requires special handling */
                    uid = (uid_t) strtol (given + allow_len, &endp, 10);
                    if (*endp != '\0') {
                        printf ("'%s' is not a number?\n", given);
                        unknown_error ("option uid is malformed");
                    }
#ifdef DEBUG
                    printf ("%s with uid %d\n", allow, uid);
#endif
                    wants_to_change_uid = TRUE;

                    goto option_ok;
                } else {

                    goto option_ok;
                }
            }
        }

        /* apparently option was not ok */
        invalid_mount_option (given, invoked_by_uid);

    option_ok:
        ;
    }

    /* Check privilege */
    pol_is_fixed = TRUE;
    if (libhal_drive_is_hotpluggable (drive) || libhal_drive_uses_removable_media (drive))
        pol_is_fixed = FALSE;

    pol_change_uid = FALSE;
    /* don't consider uid= on non-pollable drives for the purpose of policy
     * (since these drives normally use vfat)
     */
    if (volume != NULL) {
        /* don't consider uid= on vfat, iso9660, udf change-uid for the purpose of policy
         * (since these doesn't contain uid/gid bits)
         */
        if (strcmp (libhal_volume_get_fstype (volume), "vfat") != 0 &&
            strcmp (libhal_volume_get_fstype (volume), "iso9660") != 0 &&
            strcmp (libhal_volume_get_fstype (volume), "udf") != 0) {
            pol_change_uid = wants_to_change_uid;
        }
    }

    if (pol_is_fixed) {
        if (pol_change_uid) {
            privilege = "hal-storage-fixed-mount-all-options";
        } else {
            privilege = "hal-storage-fixed-mount";
        }
    } else {
        if (pol_change_uid) {
            privilege = "hal-storage-removable-mount-all-options";
        } else {
            privilege = "hal-storage-removable-mount";
        }
    }

#ifdef DEBUG
    printf ("using privilege %s for uid %s, system_bus_connection %s\n", privilege, invoked_by_uid,
        invoked_by_syscon_name);
#endif

#ifdef HAVE_POLKIT
    if (libpolkit_is_uid_allowed_for_privilege (pol_ctx,
                            invoked_by_syscon_name,
                            invoked_by_uid,
                            privilege,
                            udi,
                            &allowed_by_privilege,
                            &is_temporary_privilege,
                            NULL) != LIBPOLKIT_RESULT_OK) {
        printf ("cannot lookup privilege\n");
        unknown_error ("Cannot lookup privilege from PolicyKit");
    }

    if (!allowed_by_privilege) {
        printf ("caller don't possess privilege\n");
        permission_denied_privilege (privilege, invoked_by_uid);
    }
#endif

#ifdef DEBUG
    printf ("passed privilege\n");
#endif

    if (!is_remount) {
        /* create directory */
#ifdef sun
        if (!g_file_test (mount_dir, G_FILE_TEST_EXISTS) &&
            (g_mkdir (mount_dir, 0755) != 0)) {
#else
        if (g_mkdir (mount_dir, 0700) != 0) {
#endif
            printf ("Cannot create '%s'\n", mount_dir);
            unknown_error ("Cannot create mount directory");
        }

#ifdef __FreeBSD__
        calling_uid = (uid_t) strtol (invoked_by_uid, (char **) NULL, 10);
        pw = getpwuid (calling_uid);
        if (pw != NULL) {
            calling_gid = pw->pw_gid;
        } else {
            calling_gid = 0;
        }
        if (chown (mount_dir, calling_uid, calling_gid) != 0) {
            printf ("Cannot chown '%s' to uid: %d, gid: %d\n", mount_dir,
                calling_uid, calling_gid);
            g_rmdir (mount_dir);
            unknown_error ();
        }
#endif
    }

    char *mount_option_commasep = NULL;
    char *mount_do_fstype = "auto";

    /* construct arguments to mount */
    na = 0;
    args[na++] = MOUNT;
    if (strlen (mount_fstype) > 0) {
        mount_do_fstype = (char *) map_fstype (mount_fstype);
    } else if (volume == NULL) {
        /* non-pollable drive; force auto */
        mount_do_fstype = "auto";
    } else if (libhal_volume_get_fstype (volume) != NULL && strlen (libhal_volume_get_fstype (volume)) > 0) {
        mount_do_fstype = (char *) map_fstype (libhal_volume_get_fstype (volume));
    }
    args[na++] = MOUNT_TYPE_OPT;
    args[na++] = mount_do_fstype;

    args[na++] = "-o";
    mount_option_str = g_string_new (MOUNT_OPTIONS);
    for (i = 0; given_options[i] != NULL; i++) {
        g_string_append (mount_option_str, ",");
        g_string_append (mount_option_str, given_options[i]);
    }
#ifdef sun
    if (append_ro) {
        g_string_append (mount_option_str, ",ro");
    }
#endif
    mount_option_commasep = g_string_free (mount_option_str, FALSE); /* leak! */
    args[na++] = mount_option_commasep;
    args[na++] = (char *) device;
    args[na++] = mount_dir;
    args[na++] = NULL;

    /* TODO FIXME XXX HACK: OK, so we should rewrite the options in /media/.hal-mtab ..
     *                      but it doesn't really matter much at this point */
    if (!is_remount) {
        FILE *hal_mtab;
        char *mount_dir_escaped;
        FILE *hal_mtab_orig;
        int hal_mtab_orig_len;
        int num_read;
        char *hal_mtab_buf;
        char *hal_mtab_buf_old;

        /* Maintain a list in /media/.hal-mtab with entries of the following format
         *
         *  <device_file>\t<uid>\t<session-id>\t<fstype>\t<options_sep_by_comma>\t<mount point>\n
         *
         * where session-id currently is unused and thus set to 0.
         *
         * Example:
         *
         *  /dev/sda2   500 0   hfsplus noexec,nosuid,nodev /media/Macintosh HD
         *  /dev/sda4   500 0   ntfs    noexec,nosuid,nodev,umask=222   /media/Windows
         *  /dev/sdb1   500 0   vfat    noexec,nosuid,nodev,shortname=winnt,uid=500 /media/davidz
         */


        if (g_file_test ("/media/.hal-mtab", G_FILE_TEST_EXISTS)) {
            hal_mtab_orig = fopen ("/media/.hal-mtab", "r");
            if (hal_mtab_orig == NULL) {
                unknown_error ("Cannot open /media/.hal-mtab");
            }
            if (fseek (hal_mtab_orig, 0L, SEEK_END) != 0) {
                unknown_error ("Cannot seek to end of /media/.hal-mtab");
            }
            hal_mtab_orig_len = ftell (hal_mtab_orig);
            if (hal_mtab_orig_len < 0) {
                unknown_error ("Cannot determine size of /media/.hal-mtab");
            }
            rewind (hal_mtab_orig);
            hal_mtab_buf = g_new0 (char, hal_mtab_orig_len + 1);
            num_read = fread (hal_mtab_buf, 1, hal_mtab_orig_len, hal_mtab_orig);
            if (num_read != hal_mtab_orig_len) {
                unknown_error ("Cannot read from /media/.hal-mtab");
            }
            fclose (hal_mtab_orig);
        } else {
            hal_mtab_buf = g_strdup ("");
        }

        mount_dir_escaped = g_strescape (mount_dir, NULL);
#ifdef DEBUG
        printf ("%d: XYA creating /media/.hal-mtab~\n", getpid ());
#endif
        hal_mtab = fopen ("/media/.hal-mtab~", "w");
        if (hal_mtab == NULL) {
            unknown_error ("Cannot create /media/.hal-mtab~");
        }
        hal_mtab_buf_old = hal_mtab_buf;
        hal_mtab_buf = g_strdup_printf ("%s%s\t%s\t0\t%s\t%s\t%s\n",
                        hal_mtab_buf_old,
                        device, invoked_by_uid, mount_do_fstype,
                        mount_option_commasep, mount_dir_escaped);
        g_free (hal_mtab_buf_old);
        if (hal_mtab_buf_old == NULL) {
            unknown_error ("Out of memory appending to /media/.hal-mtab~");
        }
        if (fwrite (hal_mtab_buf, 1, strlen (hal_mtab_buf), hal_mtab) != strlen (hal_mtab_buf)) {
            unknown_error ("Cannot write to /media/.hal-mtab~");
        }
        fclose (hal_mtab);
        g_free (hal_mtab_buf);
        g_free (mount_dir_escaped);
#ifdef DEBUG
        printf ("%d: XYA closing /media/.hal-mtab~\n", getpid ());
#endif
    } /* !is_remount */

    /* now try to mount */
    if (!g_spawn_sync ("/",
               args,
               NULL,
               0,
               NULL,
               NULL,
               &sout,
               &serr,
               &exit_status,
               &err)) {
        printf ("Cannot execute %s\n", MOUNT);
        g_rmdir (mount_dir);
        unlink ("/media/.hal-mtab~");
        unknown_error ("Cannot spawn " MOUNT);
    }


    if (exit_status != 0) {
        char errstr[]  = "mount: unknown filesystem type";

        printf ("%s error %d, stdout='%s', stderr='%s'\n", MOUNT, exit_status, sout, serr);

        if (!is_remount) {
            g_rmdir (mount_dir);
            unlink ("/media/.hal-mtab~");
        }

        if (strncmp (errstr, serr, sizeof (errstr) - 1) == 0) {
            unknown_filesystem (strlen (mount_fstype) > 0 ?
                        mount_fstype :
                        (volume != NULL ? libhal_volume_get_fstype (volume) : "") );
        } else {
            int n;
            for (n = 0; serr[n] != '\0'; n++) {
                if (serr[n] == '\n') {
                    serr[n] = ' ';
                }
            }
            unknown_error (serr);
        }
    }

    if (!is_remount) {
        if (rename ("/media/.hal-mtab~", "/media/.hal-mtab") != 0) {
            printf ("rename(2) failed, errno=%d -> '%s'\n", errno, strerror (errno));
            unlink ("/media/.hal-mtab~");
#ifdef DEBUG
            printf ("%d: XYA failed renaming /media/.hal-mtab~ to /media/.hal-mtab\n", getpid ());
#endif
            unknown_error ("Cannot rename /media/.hal-mtab~ to /media/.hal-mtab");
        }
#ifdef DEBUG
        printf ("%d: XYA done renaming /media/.hal-mtab~ to /media/.hal-mtab\n", getpid ());
#endif
    }

    openlog ("hald", 0, LOG_DAEMON);
    if (is_remount) {
        syslog (LOG_INFO, "remounted %s at '%s' on behalf of uid %s", device, mount_dir, invoked_by_uid);
    } else {
        syslog (LOG_INFO, "mounted %s on behalf of uid %s", device, invoked_by_uid);
    }
    closelog ();

#ifdef sun
    if ((adt_data = get_audit_export_data (system_bus,
        invoked_by_syscon_name, &adt_data_size)) != NULL) {
        audit_volume (adt_data, ADT_attach,
            WEXITSTATUS(exit_status), auth_from_privilege(privilege),
            mount_dir, device, mount_option_commasep);
        free (adt_data);
    }
#endif

    g_free (sout);
    g_free (serr);
    g_free (mount_dir);
    libhal_free_string_array (allowed_options);
    g_strfreev (given_options);
}


int
main (int argc, char *argv[])
{
    char *udi;
    char *device;
    LibHalVolume *volume;
    DBusError error;
    LibHalContext *hal_ctx = NULL;
    DBusConnection *system_bus = NULL;
#ifdef HAVE_POLKIT
    LibPolKitContext *pol_ctx = NULL;
#endif
    char *invoked_by_uid;
    char *invoked_by_syscon_name;

    if (!lock_hal_mtab ()) {
        unknown_error ("Cannot obtain lock on /media/.hal-mtab");
    }

    device = getenv ("HAL_PROP_BLOCK_DEVICE");
    if (device == NULL)
        usage ();

    udi = getenv ("HAL_PROP_INFO_UDI");
    if (udi == NULL)
        usage ();

    invoked_by_uid = getenv ("HAL_METHOD_INVOKED_BY_UID");

    invoked_by_syscon_name = getenv ("HAL_METHOD_INVOKED_BY_SYSTEMBUS_CONNECTION_NAME");

    dbus_error_init (&error);
    if ((hal_ctx = libhal_ctx_init_direct (&error)) == NULL) {
        printf ("Cannot connect to hald\n");
        LIBHAL_FREE_DBUS_ERROR (&error);
        usage ();
    }

    dbus_error_init (&error);
    system_bus = dbus_bus_get (DBUS_BUS_SYSTEM, &error);
    if (system_bus == NULL) {
        printf ("Cannot connect to the system bus\n");
        LIBHAL_FREE_DBUS_ERROR (&error);
        usage ();
    }
#ifdef HAVE_POLKIT
    pol_ctx = libpolkit_new_context (system_bus);
    if (pol_ctx == NULL) {
        printf ("Cannot get libpolkit context\n");
        unknown_error ("Cannot get libpolkit context");
    }
#endif

    volume = libhal_volume_from_udi (hal_ctx, udi);
    if (volume == NULL) {
        LibHalDrive *drive;

        drive = libhal_drive_from_udi (hal_ctx, udi);
        if (drive == NULL) {
            usage ();
        } else {
            handle_mount (hal_ctx,
#ifdef HAVE_POLKIT
                      pol_ctx,
#endif
                      udi, NULL, drive, device, invoked_by_uid,
                      invoked_by_syscon_name, system_bus);
        }

    } else {
        const char *drive_udi;
        LibHalDrive *drive;

        drive_udi = libhal_volume_get_storage_device_udi (volume);

        if (drive_udi == NULL)
            unknown_error ("Cannot get drive_udi from volume");
        drive = libhal_drive_from_udi (hal_ctx, drive_udi);
        if (drive == NULL)
            unknown_error ("Cannot get drive from hal");

        handle_mount (hal_ctx,
#ifdef HAVE_POLKIT
                  pol_ctx,
#endif
                  udi, volume, drive, device, invoked_by_uid,
                  invoked_by_syscon_name, system_bus);

    }

    unlock_hal_mtab ();

    return 0;
}