libfdisk: add fdisk_assign_device_by_fd()

[thirdparty/util-linux.git] / libfdisk / src / context.c

#ifdef HAVE_LIBBLKID
# include <blkid.h>
#endif

#include "blkdev.h"
#ifdef __linux__
# include "partx.h"
#endif
#include "loopdev.h"
#include "fdiskP.h"


/**
 * SECTION: context
 * @title: Context
 * @short_description: stores info about device, labels etc.
 *
 * The library distinguish between three types of partitioning objects.
 *
 * on-disk lebel data
 *    - disk label specific
 *    - probed and read  by disklabel drivers when assign device to the context
 *      or when switch to another disk label type
 *    - only fdisk_write_disklabel() modify on-disk data
 *
 * in-memory label data
 *    - generic data and disklabel specific data stored in struct fdisk_label
 *    - all partitioning operations are based on in-memory data only
 *
 * struct fdisk_partition
 *    - provides abstraction to present partitions to users
 *    - fdisk_partition is possible to gather to fdisk_table container
 *    - used as unified template for new partitions
 *    - used (with fdisk_table) in fdisk scripts
 *    - the struct fdisk_partition is always completely independent object and
 *      any change to the object has no effect to in-memory (or on-disk) label data
 *
 * Don't forget to inform kernel about changes by fdisk_reread_partition_table()
 * or more smart fdisk_reread_changes().
 */

/**
 * fdisk_new_context:
 *
 * Returns: newly allocated libfdisk handler
 */
struct fdisk_context *fdisk_new_context(void)
{
        struct fdisk_context *cxt;

        cxt = calloc(1, sizeof(*cxt));
        if (!cxt)
                return NULL;

        DBG(CXT, ul_debugobj(cxt, "alloc"));
        cxt->dev_fd = -1;
        cxt->refcount = 1;

        INIT_LIST_HEAD(&cxt->wipes);

        /*
         * Allocate label specific structs.
         *
         * This is necessary (for example) to store label specific
         * context setting.
         */
        cxt->labels[ cxt->nlabels++ ] = fdisk_new_gpt_label(cxt);
        cxt->labels[ cxt->nlabels++ ] = fdisk_new_dos_label(cxt);
        cxt->labels[ cxt->nlabels++ ] = fdisk_new_bsd_label(cxt);
        cxt->labels[ cxt->nlabels++ ] = fdisk_new_sgi_label(cxt);
        cxt->labels[ cxt->nlabels++ ] = fdisk_new_sun_label(cxt);

        bindtextdomain(LIBFDISK_TEXTDOMAIN, LOCALEDIR);

        return cxt;
}

static int init_nested_from_parent(struct fdisk_context *cxt, int isnew)
{
        struct fdisk_context *parent;

        assert(cxt);
        assert(cxt->parent);

        parent = cxt->parent;

        cxt->alignment_offset = parent->alignment_offset;
        cxt->ask_cb =           parent->ask_cb;
        cxt->ask_data =         parent->ask_data;
        cxt->dev_fd =           parent->dev_fd;
        cxt->first_lba =        parent->first_lba;
        cxt->firstsector_bufsz = parent->firstsector_bufsz;
        cxt->firstsector =      parent->firstsector;
        cxt->geom =             parent->geom;
        cxt->grain =            parent->grain;
        cxt->io_size =          parent->io_size;
        cxt->last_lba =         parent->last_lba;
        cxt->min_io_size =      parent->min_io_size;
        cxt->optimal_io_size =  parent->optimal_io_size;
        cxt->phy_sector_size =  parent->phy_sector_size;
        cxt->readonly =         parent->readonly;
        cxt->script =           parent->script;
        fdisk_ref_script(cxt->script);
        cxt->sector_size =      parent->sector_size;
        cxt->total_sectors =    parent->total_sectors;
        cxt->user_geom =        parent->user_geom;
        cxt->user_log_sector =  parent->user_log_sector;
        cxt->user_pyh_sector =  parent->user_pyh_sector;

        /* parent <--> nested independent setting, initialize for new nested
         * contexts only */
        if (isnew) {
                cxt->listonly = parent->listonly;
                cxt->display_details =  parent->display_details;
                cxt->display_in_cyl_units = parent->display_in_cyl_units;
                cxt->protect_bootbits = parent->protect_bootbits;
        }

        free(cxt->dev_model);
        cxt->dev_model = NULL;
        cxt->dev_model_probed = 0;

        free(cxt->dev_path);
        cxt->dev_path = NULL;

        if (parent->dev_path) {
                cxt->dev_path = strdup(parent->dev_path);
                if (!cxt->dev_path)
                        return -ENOMEM;
        }

        INIT_LIST_HEAD(&cxt->wipes);

        return 0;
}

/**
 * fdisk_new_nested_context:
 * @parent: parental context
 * @name: optional label name (e.g. "bsd")
 *
 * Create a new nested fdisk context for nested disk labels (e.g. BSD or PMBR).
 * The function also probes for the nested label on the device if device is
 * already assigned to parent.
 *
 * The new context is initialized according to @parent and both context shares
 * some settings and file descriptor to the device. The child propagate some
 * changes (like fdisk_assign_device()) to parent, but it does not work
 * vice-versa. The behavior is undefined if you assign another device to
 * parent.
 *
 * Returns: new context for nested partition table.
 */
struct fdisk_context *fdisk_new_nested_context(struct fdisk_context *parent,
                                const char *name)
{
        struct fdisk_context *cxt;
        struct fdisk_label *lb = NULL;

        assert(parent);

        cxt = calloc(1, sizeof(*cxt));
        if (!cxt)
                return NULL;

        DBG(CXT, ul_debugobj(parent, "alloc nested [%p] [name=%s]", cxt, name));
        cxt->refcount = 1;

        fdisk_ref_context(parent);
        cxt->parent = parent;

        if (init_nested_from_parent(cxt, 1) != 0) {
                cxt->parent = NULL;
                fdisk_unref_context(cxt);
                return NULL;
        }

        if (name) {
                if (strcasecmp(name, "bsd") == 0)
                        lb = cxt->labels[ cxt->nlabels++ ] = fdisk_new_bsd_label(cxt);
                else if (strcasecmp(name, "dos") == 0 || strcasecmp(name, "mbr") == 0)
                        lb = cxt->labels[ cxt->nlabels++ ] = fdisk_new_dos_label(cxt);
        }

        if (lb && parent->dev_fd >= 0) {
                DBG(CXT, ul_debugobj(cxt, "probing for nested %s", lb->name));

                cxt->label = lb;

                if (lb->op->probe(cxt) == 1)
                        __fdisk_switch_label(cxt, lb);
                else {
                        DBG(CXT, ul_debugobj(cxt, "not found %s label", lb->name));
                        if (lb->op->deinit)
                                lb->op->deinit(lb);
                        cxt->label = NULL;
                }
        }

        return cxt;
}


/**
 * fdisk_ref_context:
 * @cxt: context pointer
 *
 * Increments reference counter.
 */
void fdisk_ref_context(struct fdisk_context *cxt)
{
        if (cxt)
                cxt->refcount++;
}

/**
 * fdisk_get_label:
 * @cxt: context instance
 * @name: label name (e.g. "gpt")
 *
 * If no @name specified then returns the current context label.
 *
 * The label is allocated and maintained within the context #cxt. There is
 * nothing like reference counting for labels, you cannot deallocate the
 * label.
 *
 * Returns: label struct or NULL in case of error.
 */
struct fdisk_label *fdisk_get_label(struct fdisk_context *cxt, const char *name)
{
        size_t i;

        assert(cxt);

        if (!name)
                return cxt->label;
        else if (strcasecmp(name, "mbr") == 0)
                name = "dos";

        for (i = 0; i < cxt->nlabels; i++)
                if (cxt->labels[i]
                    && strcasecmp(cxt->labels[i]->name, name) == 0)
                        return cxt->labels[i];

        DBG(CXT, ul_debugobj(cxt, "failed to found %s label driver", name));
        return NULL;
}

/**
 * fdisk_next_label:
 * @cxt: context instance
 * @lb: returns pointer to the next label
 *
 * <informalexample>
 *   <programlisting>
 *      // print all supported labels
 *      struct fdisk_context *cxt = fdisk_new_context();
 *      struct fdisk_label *lb = NULL;
 *
 *      while (fdisk_next_label(cxt, &lb) == 0)
 *              print("label name: %s\n", fdisk_label_get_name(lb));
 *      fdisk_unref_context(cxt);
 *   </programlisting>
 * </informalexample>
 *
 * Returns: <0 in case of error, 0 on success, 1 at the end.
 */
int fdisk_next_label(struct fdisk_context *cxt, struct fdisk_label **lb)
{
        size_t i;
        struct fdisk_label *res = NULL;

        if (!lb || !cxt)
                return -EINVAL;

        if (!*lb)
                res = cxt->labels[0];
        else {
                for (i = 1; i < cxt->nlabels; i++) {
                        if (*lb == cxt->labels[i - 1]) {
                                res = cxt->labels[i];
                                break;
                        }
                }
        }

        *lb = res;
        return res ? 0 : 1;
}

/**
 * fdisk_get_nlabels:
 * @cxt: context
 *
 * Returns: number of supported label types
 */
size_t fdisk_get_nlabels(struct fdisk_context *cxt)
{
        return cxt ? cxt->nlabels : 0;
}

int __fdisk_switch_label(struct fdisk_context *cxt, struct fdisk_label *lb)
{
        if (!lb || !cxt)
                return -EINVAL;
        if (lb->disabled) {
                DBG(CXT, ul_debugobj(cxt, "*** attempt to switch to disabled label %s -- ignore!", lb->name));
                return -EINVAL;
        }
        cxt->label = lb;
        DBG(CXT, ul_debugobj(cxt, "--> switching context to %s!", lb->name));

        fdisk_apply_label_device_properties(cxt);
        return 0;
}

/**
 * fdisk_has_label:
 * @cxt: fdisk context
 *
 * Returns: return 1 if there is label on the device.
 */
int fdisk_has_label(struct fdisk_context *cxt)
{
        return cxt && cxt->label;
}

/**
 * fdisk_has_protected_bootbits:
 * @cxt: fdisk context
 *
 * Returns: return 1 if boot bits protection enabled.
 */
int fdisk_has_protected_bootbits(struct fdisk_context *cxt)
{
        return cxt && cxt->protect_bootbits;
}

/**
 * fdisk_enable_bootbits_protection:
 * @cxt: fdisk context
 * @enable: 1 or 0
 *
 * The library zeroizes all the first sector when create a new disk label by
 * default.  This function allows to control this behavior. For now it's
 * supported for MBR and GPT.
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_enable_bootbits_protection(struct fdisk_context *cxt, int enable)
{
        if (!cxt)
                return -EINVAL;
        cxt->protect_bootbits = enable ? 1 : 0;
        return 0;
}
/**
 * fdisk_disable_dialogs
 * @cxt: fdisk context
 * @disable: 1 or 0
 *
 * The library uses dialog driven partitioning by default.
 *
 * Returns: 0 on success, < 0 on error.
 *
 * Since: 2.31
 */
int fdisk_disable_dialogs(struct fdisk_context *cxt, int disable)
{
        if (!cxt)
                return -EINVAL;

        cxt->no_disalogs = disable;
        return 0;
}

/**
 * fdisk_has_dialogs
 * @cxt: fdisk context
 *
 * See fdisk_disable_dialogs()
 *
 * Returns: 1 if dialog driven partitioning enabled (default), or 0.
 *
 * Since: 2.31
 */
int fdisk_has_dialogs(struct fdisk_context *cxt)
{
        return cxt->no_disalogs == 0;
}

/**
 * fdisk_enable_wipe
 * @cxt: fdisk context
 * @enable: 1 or 0
 *
 * The library removes all PT/filesystem/RAID signatures before it writes
 * partition table. The probing area where it looks for signatures is from
 * the begin of the disk. The device is wiped by libblkid.
 *
 * See also fdisk_wipe_partition().
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_enable_wipe(struct fdisk_context *cxt, int enable)
{
        if (!cxt)
                return -EINVAL;

        fdisk_set_wipe_area(cxt, 0, cxt->total_sectors, enable);
        return 0;
}

/**
 * fdisk_has_wipe
 * @cxt: fdisk context
 *
 * Returns the current wipe setting. See fdisk_enable_wipe().
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_has_wipe(struct fdisk_context *cxt)
{
        if (!cxt)
                return 0;

        return fdisk_has_wipe_area(cxt, 0, cxt->total_sectors);
}


/**
 * fdisk_get_collision
 * @cxt: fdisk context
 *
 * Returns: name of the filesystem or RAID detected on the device or NULL.
 */
const char *fdisk_get_collision(struct fdisk_context *cxt)
{
        return cxt->collision;
}

/**
 * fdisk_is_ptcollision:
 * @cxt: fdisk context
 *
 * The collision detected by libblkid (usually another partition table). Note
 * that libfdisk does not support all partitions tables, so fdisk_has_label()
 * may return false, but fdisk_is_ptcollision() may return true.
 *
 * Since: 2.30
 *
 * Returns: 0 or 1
 */
int fdisk_is_ptcollision(struct fdisk_context *cxt)
{
        return cxt->pt_collision;
}

/**
 * fdisk_get_npartitions:
 * @cxt: context
 *
 * The maximal number of the partitions depends on disklabel and does not
 * have to describe the real limit of PT.
 *
 * For example the limit for MBR without extend partition is 4, with extended
 * partition it's unlimited (so the function returns the current number of all
 * partitions in this case).
 *
 * And for example for GPT it depends on space allocated on disk for array of
 * entry records (usually 128).
 *
 * It's fine to use fdisk_get_npartitions() in loops, but don't forget that
 * partition may be unused (see fdisk_is_partition_used()).
 *
 * <informalexample>
 *   <programlisting>
 *      struct fdisk_partition *pa = NULL;
 *      size_t i, nmax = fdisk_get_npartitions(cxt);
 *
 *      for (i = 0; i < nmax; i++) {
 *              if (!fdisk_is_partition_used(cxt, i))
 *                      continue;
 *              ... do something ...
 *      }
 *   </programlisting>
 * </informalexample>
 *
 * Note that the recommended way to list partitions is to use
 * fdisk_get_partitions() and struct fdisk_table than ask disk driver for each
 * individual partitions.
 *
 * Returns: maximal number of partitions for the current label.
 */
size_t fdisk_get_npartitions(struct fdisk_context *cxt)
{
        return cxt && cxt->label ? cxt->label->nparts_max : 0;
}

/**
 * fdisk_is_labeltype:
 * @cxt: fdisk context
 * @id: FDISK_DISKLABEL_*
 *
 * See also fdisk_is_label() macro in libfdisk.h.
 *
 * Returns: return 1 if the current label is @id
 */
int fdisk_is_labeltype(struct fdisk_context *cxt, enum fdisk_labeltype id)
{
        assert(cxt);

        return cxt->label && (unsigned)fdisk_label_get_type(cxt->label) == id;
}

/**
 * fdisk_get_parent:
 * @cxt: nested fdisk context
 *
 * Returns: pointer to parental context, or NULL
 */
struct fdisk_context *fdisk_get_parent(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->parent;
}

static void reset_context(struct fdisk_context *cxt)
{
        size_t i;

        DBG(CXT, ul_debugobj(cxt, "*** resetting context"));

        /* reset drives' private data */
        for (i = 0; i < cxt->nlabels; i++)
                fdisk_deinit_label(cxt->labels[i]);

        if (cxt->parent) {
                /* the first sector may be independent on parent */
                if (cxt->parent->firstsector != cxt->firstsector)
                        free(cxt->firstsector);
        } else {
                /* we close device only in primary context */
                if (cxt->dev_fd > -1 && cxt->private_fd)
                        close(cxt->dev_fd);
                free(cxt->firstsector);
        }

        free(cxt->dev_path);
        cxt->dev_path = NULL;

        free(cxt->dev_model);
        cxt->dev_model = NULL;
        cxt->dev_model_probed = 0;

        free(cxt->collision);
        cxt->collision = NULL;

        memset(&cxt->dev_st, 0, sizeof(cxt->dev_st));

        cxt->dev_fd = -1;
        cxt->private_fd = 0;
        cxt->firstsector = NULL;
        cxt->firstsector_bufsz = 0;

        fdisk_zeroize_device_properties(cxt);

        fdisk_unref_script(cxt->script);
        cxt->script = NULL;

        cxt->label = NULL;

        fdisk_free_wipe_areas(cxt);
}

/* fdisk_assign_device() body */
static int fdisk_assign_fd(struct fdisk_context *cxt, int fd,
                        const char *fname, int readonly, int privfd)
{
        assert(cxt);
        assert(fd >= 0);

        /* redirect request to parent */
        if (cxt->parent) {
                int rc, org = fdisk_is_listonly(cxt->parent);

                /* assign_device() is sensitive to "listonly" mode, so let's
                 * follow the current context setting for the parent to avoid
                 * unwanted extra warnings. */
                fdisk_enable_listonly(cxt->parent, fdisk_is_listonly(cxt));

                rc = fdisk_assign_fd(cxt->parent, fd, fname, readonly, privfd);
                fdisk_enable_listonly(cxt->parent, org);

                if (!rc)
                        rc = init_nested_from_parent(cxt, 0);
                if (!rc)
                        fdisk_probe_labels(cxt);
                return rc;
        }

        reset_context(cxt);

        if (fstat(fd, &cxt->dev_st) != 0)
                goto fail;

        cxt->readonly = readonly;
        cxt->dev_fd = fd;
        cxt->private_fd = privfd;
        cxt->dev_path = fname ? strdup(fname) : NULL;
        if (!cxt->dev_path)
                goto fail;

        fdisk_discover_topology(cxt);
        fdisk_discover_geometry(cxt);

        fdisk_apply_user_device_properties(cxt);

        if (fdisk_read_firstsector(cxt) < 0)
                goto fail;

        fdisk_probe_labels(cxt);
        fdisk_apply_label_device_properties(cxt);

        /* warn about obsolete stuff on the device if we aren't in
         * list-only mode and there is not PT yet */
        if (!fdisk_is_listonly(cxt) && !fdisk_has_label(cxt)
            && fdisk_check_collisions(cxt) < 0)
                goto fail;

        DBG(CXT, ul_debugobj(cxt, "initialized for %s [%s]",
                              fname, readonly ? "READ-ONLY" : "READ-WRITE"));
        return 0;
fail:
        {
                int rc = -errno;
                DBG(CXT, ul_debugobj(cxt, "failed to assign device [rc=%d]", rc));
                return rc;
        }
}

/**
 * fdisk_assign_device:
 * @cxt: context
 * @fname: path to the device to be handled
 * @readonly: how to open the device
 *
 * Open the device, discovery topology, geometry, detect disklabel, check for
 * collisions and switch the current label driver to reflect the probing
 * result.
 *
 * If in standard mode (!= non-listonly mode) than also detects for collisions.
 * The result is accessible by fdisk_get_collision() and
 * fdisk_is_ptcollision().  The collision (e.g. old obsolete PT) may be removed
 * by fdisk_enable_wipe().  Note that new PT and old PT may be on different
 * locations.
 *
 * Note that this function resets all generic setting in context.
 *
 * If the @cxt is nested context (necessary for example to edit BSD or PMBR)
 * then the device is assigned to the parental context and necessary properties
 * are copied to the @cxt. The change is propagated in child->parent direction
 * only. It's impossible to use a different device for primary and nested
 * contexts.
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_assign_device(struct fdisk_context *cxt,
                        const char *fname, int readonly)
{
        int fd, rc;

        DBG(CXT, ul_debugobj(cxt, "assigning device %s", fname));
        assert(cxt);

        fd = open(fname, (readonly ? O_RDONLY : O_RDWR ) | O_CLOEXEC);
        if (fd < 0) {
                int rc = -errno;
                DBG(CXT, ul_debugobj(cxt, "failed to assign device [rc=%d]", rc));
                return rc;
        }

        rc = fdisk_assign_fd(cxt, fd, fname, readonly, 1);
        if (rc)
                close(fd);
        return rc;
}

/**
 * fdisk_assign_device_by_fd:
 * @cxt: context
 * @fd: device file descriptor
 * @fname: path to the device (used for dialogs, debugging, partition names, ...)
 * @readonly: how to use the device
 *
 * Like fdisk_assign_device(), but caller is responsible to open and close the
 * device. The library only fsync() the device on fdisk_deassign_device().
 *
 * The device has to be open O_RDWR on @readonly=0.
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_assign_device_by_fd(struct fdisk_context *cxt, int fd,
                        const char *fname, int readonly)
{
        return fdisk_assign_fd(cxt, fd, fname, readonly, 0);
}

/**
 * fdisk_deassign_device:
 * @cxt: context
 * @nosync: disable fsync()
 *
 * Close device and call fsync(). If the @cxt is nested context than the
 * request is redirected to the parent.
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_deassign_device(struct fdisk_context *cxt, int nosync)
{
        assert(cxt);
        assert(cxt->dev_fd >= 0);

        if (cxt->parent) {
                int rc = fdisk_deassign_device(cxt->parent, nosync);

                if (!rc)
                        rc = init_nested_from_parent(cxt, 0);
                return rc;
        }

        DBG(CXT, ul_debugobj(cxt, "de-assigning device %s", cxt->dev_path));

        if (cxt->readonly && cxt->private_fd)
                close(cxt->dev_fd);
        else {
                if (fsync(cxt->dev_fd)) {
                        fdisk_warn(cxt, _("%s: fsync device failed"),
                                        cxt->dev_path);
                        return -errno;
                }
                if (cxt->private_fd && close(cxt->dev_fd)) {
                        fdisk_warn(cxt, _("%s: close device failed"),
                                        cxt->dev_path);
                        return -errno;
                }
                if (!nosync) {
                        fdisk_info(cxt, _("Syncing disks."));
                        sync();
                }
        }

        free(cxt->dev_path);
        cxt->dev_path = NULL;
        cxt->dev_fd = -1;

        return 0;
}

/**
 * fdisk_reassign_device:
 * @cxt: context
 *
 * This function is "hard reset" of the context and it does not write anything
 * to the device. All in-memory changes associated with the context will be
 * lost. It's recommended to use this function after some fatal problem when the
 * context (and label specific driver) is in an undefined state.
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_reassign_device(struct fdisk_context *cxt)
{
        char *devname;
        int rdonly, rc, fd, privfd;

        assert(cxt);
        assert(cxt->dev_fd >= 0);

        DBG(CXT, ul_debugobj(cxt, "re-assigning device %s", cxt->dev_path));

        devname = strdup(cxt->dev_path);
        if (!devname)
                return -ENOMEM;

        rdonly = cxt->readonly;
        fd = cxt->dev_fd;
        privfd = cxt->private_fd;

        fdisk_deassign_device(cxt, 1);

        if (privfd)
                /* reopen and assign */
                rc = fdisk_assign_device(cxt, devname, rdonly);
        else
                /* assign only */
                rc = fdisk_assign_fd(cxt, fd, devname, rdonly, privfd);

        free(devname);
        return rc;
}

/**
 * fdisk_reread_partition_table:
 * @cxt: context
 *
 * Force *kernel* to re-read partition table on block devices.
 *
 * Returns: 0 on success, < 0 in case of error.
 */
int fdisk_reread_partition_table(struct fdisk_context *cxt)
{
        int i = 0;

        assert(cxt);
        assert(cxt->dev_fd >= 0);

        if (!S_ISBLK(cxt->dev_st.st_mode))
                return 0;
        else {
                DBG(CXT, ul_debugobj(cxt, "calling re-read ioctl"));
                sync();
#ifdef BLKRRPART
                fdisk_info(cxt, _("Calling ioctl() to re-read partition table."));
                i = ioctl(cxt->dev_fd, BLKRRPART);
#else
                errno = ENOSYS;
                i = 1;
#endif
        }

        if (i) {
                fdisk_warn(cxt, _("Re-reading the partition table failed."));
                fdisk_info(cxt, _(
                        "The kernel still uses the old table. The "
                        "new table will be used at the next reboot "
                        "or after you run partprobe(8) or kpartx(8)."));
                return -errno;
        }

        return 0;
}

#ifdef __linux__
static inline int add_to_partitions_array(
                        struct fdisk_partition ***ary,
                        struct fdisk_partition *pa,
                        size_t *n, size_t nmax)
{
        if (!*ary) {
                *ary = calloc(nmax, sizeof(struct fdisk_partition *));
                if (!*ary)
                        return -ENOMEM;
        }
        (*ary)[*n] = pa;
        (*n)++;
        return 0;
}
#endif

/**
 * fdisk_reread_changes:
 * @cxt: context
 * @org: original layout (on disk)
 *
 * Like fdisk_reread_partition_table() but don't forces kernel re-read all
 * partition table. The BLKPG_* ioctls are used for individual partitions. The
 * advantage is that unmodified partitions maybe mounted.
 *
 * The function behavies like fdisk_reread_partition_table() on systems where
 * are no available BLKPG_* ioctls.
 *
 * Returns: <0 on error, or 0.
 */
#ifdef __linux__
int fdisk_reread_changes(struct fdisk_context *cxt, struct fdisk_table *org)
{
        struct fdisk_table *tb = NULL;
        struct fdisk_iter itr;
        struct fdisk_partition *pa;
        struct fdisk_partition **rem = NULL, **add = NULL, **upd = NULL;
        int change, rc = 0, err = 0;
        size_t nparts, i, nadds = 0, nupds = 0, nrems = 0;

        DBG(CXT, ul_debugobj(cxt, "rereading changes"));

        fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);

        /* the current layout */
        fdisk_get_partitions(cxt, &tb);
        /* maximal number of partitions */
        nparts = max(fdisk_table_get_nents(tb), fdisk_table_get_nents(org));

        while (fdisk_diff_tables(org, tb, &itr, &pa, &change) == 0) {
                if (change == FDISK_DIFF_UNCHANGED)
                        continue;
                switch (change) {
                case FDISK_DIFF_REMOVED:
                        rc = add_to_partitions_array(&rem, pa, &nrems, nparts);
                        break;
                case FDISK_DIFF_ADDED:
                        rc = add_to_partitions_array(&add, pa, &nadds, nparts);
                        break;
                case FDISK_DIFF_RESIZED:
                        rc = add_to_partitions_array(&upd, pa, &nupds, nparts);
                        break;
                case FDISK_DIFF_MOVED:
                        rc = add_to_partitions_array(&rem, pa, &nrems, nparts);
                        if (!rc)
                                rc = add_to_partitions_array(&add, pa, &nadds, nparts);
                        break;
                }
                if (rc != 0)
                        goto done;
        }

        for (i = 0; i < nrems; i++) {
                pa = rem[i];
                DBG(PART, ul_debugobj(pa, "#%zu calling BLKPG_DEL_PARTITION", pa->partno));
                if (partx_del_partition(cxt->dev_fd, pa->partno + 1) != 0) {
                        fdisk_warn(cxt, _("Failed to remove partition %zu from system"), pa->partno + 1);
                        err++;
                }
        }
        for (i = 0; i < nupds; i++) {
                pa = upd[i];
                DBG(PART, ul_debugobj(pa, "#%zu calling BLKPG_RESIZE_PARTITION", pa->partno));
                if (partx_resize_partition(cxt->dev_fd, pa->partno + 1, pa->start, pa->size) != 0) {
                        fdisk_warn(cxt, _("Failed to update system information about partition %zu"), pa->partno + 1);
                        err++;
                }
        }
        for (i = 0; i < nadds; i++) {
                pa = add[i];
                DBG(PART, ul_debugobj(pa, "#%zu calling BLKPG_ADD_PARTITION", pa->partno));
                if (partx_add_partition(cxt->dev_fd, pa->partno + 1, pa->start, pa->size) != 0) {
                        fdisk_warn(cxt, _("Failed to add partition %zu to system"), pa->partno + 1);
                        err++;
                }
        }
        if (err)
                fdisk_info(cxt, _(
                        "The kernel still uses the old partitions. The new "
                        "table will be used at the next reboot. "));
done:
        free(rem);
        free(add);
        free(upd);
        fdisk_unref_table(tb);
        return rc;
}
#else
int fdisk_reread_changes(struct fdisk_context *cxt,
                         struct fdisk_table *org __attribute__((__unused__))) {
        return fdisk_reread_partition_table(cxt);
}
#endif

/**
 * fdisk_device_is_used:
 * @cxt: context
 *
 * On systems where is no BLKRRPART ioctl the function returns zero and
 * sets errno to ENOSYS.
 *
 * Returns: 1 if the device assigned to the context is used by system, or 0.
 */
int fdisk_device_is_used(struct fdisk_context *cxt)
{
        int rc = 0;

        assert(cxt);
        assert(cxt->dev_fd >= 0);

        errno = 0;

#ifdef BLKRRPART
        /* it seems kernel always return EINVAL for BLKRRPART on loopdevices */
        if (S_ISBLK(cxt->dev_st.st_mode)
            && major(cxt->dev_st.st_rdev) != LOOPDEV_MAJOR) {
                DBG(CXT, ul_debugobj(cxt, "calling re-read ioctl"));
                rc = ioctl(cxt->dev_fd, BLKRRPART) != 0;
        }
#else
        errno = ENOSYS;
#endif
        DBG(CXT, ul_debugobj(cxt, "device used: %s [errno=%d]", rc ? "TRUE" : "FALSE", errno));
        return rc;
}

/**
 * fdisk_is_readonly:
 * @cxt: context
 *
 * Returns: 1 if device open readonly
 */
int fdisk_is_readonly(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->readonly;
}

/**
 * fdisk_is_regfile:
 * @cxt: context
 *
 * Since: 2.30
 *
 * Returns: 1 if open file descriptor is regular file rather than a block device.
 */
int fdisk_is_regfile(struct fdisk_context *cxt)
{
        assert(cxt);
        return S_ISREG(cxt->dev_st.st_mode);
}

/**
 * fdisk_unref_context:
 * @cxt: fdisk context
 *
 * Deallocates context struct.
 */
void fdisk_unref_context(struct fdisk_context *cxt)
{
        unsigned i;

        if (!cxt)
                return;

        cxt->refcount--;
        if (cxt->refcount <= 0) {
                DBG(CXT, ul_debugobj(cxt, "freeing context %p for %s", cxt, cxt->dev_path));

                reset_context(cxt);     /* this is sensitive to parent<->child relationship! */

                /* deallocate label's private stuff */
                for (i = 0; i < cxt->nlabels; i++) {
                        if (!cxt->labels[i])
                                continue;
                        if (cxt->labels[i]->op->free)
                                cxt->labels[i]->op->free(cxt->labels[i]);
                        else
                                free(cxt->labels[i]);
                }

                fdisk_unref_context(cxt->parent);
                cxt->parent = NULL;

                free(cxt);
        }
}


/**
 * fdisk_enable_details:
 * @cxt: context
 * @enable: true/false
 *
 * Enables or disables "details" display mode. This function has effect to
 * fdisk_partition_to_string() function.
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_enable_details(struct fdisk_context *cxt, int enable)
{
        assert(cxt);
        cxt->display_details = enable ? 1 : 0;
        return 0;
}

/**
 * fdisk_is_details:
 * @cxt: context
 *
 * Returns: 1 if details are enabled
 */
int fdisk_is_details(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->display_details == 1;
}

/**
 * fdisk_enable_listonly:
 * @cxt: context
 * @enable: true/false
 *
 * Just list partition only, don't care about another details, mistakes, ...
 *
 * Returns: 0 on success, < 0 on error.
 */
int fdisk_enable_listonly(struct fdisk_context *cxt, int enable)
{
        assert(cxt);
        cxt->listonly = enable ? 1 : 0;
        return 0;
}

/**
 * fdisk_is_listonly:
 * @cxt: context
 *
 * Returns: 1 if list-only mode enabled
 */
int fdisk_is_listonly(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->listonly == 1;
}


/**
 * fdisk_set_unit:
 * @cxt: context
 * @str: "cylinder" or "sector".
 *
 * This is pure shit, unfortunately for example Sun addresses begin of the
 * partition by cylinders...
 *
 * Returns: 0 on success, <0 on error.
 */
int fdisk_set_unit(struct fdisk_context *cxt, const char *str)
{
        assert(cxt);

        cxt->display_in_cyl_units = 0;

        if (!str)
                return 0;

        if (strcmp(str, "cylinder") == 0 || strcmp(str, "cylinders") == 0)
                cxt->display_in_cyl_units = 1;

        else if (strcmp(str, "sector") == 0 || strcmp(str, "sectors") == 0)
                cxt->display_in_cyl_units = 0;

        DBG(CXT, ul_debugobj(cxt, "display unit: %s", fdisk_get_unit(cxt, 0)));
        return 0;
}

/**
 * fdisk_get_unit:
 * @cxt: context
 * @n: FDISK_PLURAL or FDISK_SINGULAR
 *
 * Returns: unit name.
 */
const char *fdisk_get_unit(struct fdisk_context *cxt, int n)
{
        assert(cxt);

        if (fdisk_use_cylinders(cxt))
                return P_("cylinder", "cylinders", n);
        return P_("sector", "sectors", n);
}

/**
 * fdisk_use_cylinders:
 * @cxt: context
 *
 * Returns: 1 if user wants to display in cylinders.
 */
int fdisk_use_cylinders(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->display_in_cyl_units == 1;
}

/**
 * fdisk_get_units_per_sector:
 * @cxt: context
 *
 * This is necessary only for brain dead situations when we use "cylinders";
 *
 * Returns: number of "units" per sector, default is 1 if display unit is sector.
 */
unsigned int fdisk_get_units_per_sector(struct fdisk_context *cxt)
{
        assert(cxt);

        if (fdisk_use_cylinders(cxt)) {
                assert(cxt->geom.heads);
                return cxt->geom.heads * cxt->geom.sectors;
        }
        return 1;
}

/**
 * fdisk_get_optimal_iosize:
 * @cxt: context
 *
 * The optimal I/O is optional and does not have to be provided by device,
 * anyway libfdisk never returns zero. If the optimal I/O size is not provided
 * then libfdisk returns minimal I/O size or sector size.
 *
 * Returns: optimal I/O size in bytes.
 */
unsigned long fdisk_get_optimal_iosize(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->optimal_io_size ? cxt->optimal_io_size : cxt->io_size;
}

/**
 * fdisk_get_minimal_iosize:
 * @cxt: context
 *
 * Returns: minimal I/O size in bytes
 */
unsigned long fdisk_get_minimal_iosize(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->min_io_size;
}

/**
 * fdisk_get_physector_size:
 * @cxt: context
 *
 * Returns: physical sector size in bytes
 */
unsigned long fdisk_get_physector_size(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->phy_sector_size;
}

/**
 * fdisk_get_sector_size:
 * @cxt: context
 *
 * Returns: logical sector size in bytes
 */
unsigned long fdisk_get_sector_size(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->sector_size;
}

/**
 * fdisk_get_alignment_offset
 * @cxt: context
 *
 * The alignment offset is offset between logical and physical sectors. For
 * backward compatibility the first logical sector on 4K disks does no have to
 * start on the same place like physical sectors.
 *
 * Returns: alignment offset in bytes
 */
unsigned long fdisk_get_alignment_offset(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->alignment_offset;
}

/**
 * fdisk_get_grain_size:
 * @cxt: context
 *
 * Returns: grain in bytes used to align partitions (usually 1MiB)
 */
unsigned long fdisk_get_grain_size(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->grain;
}

/**
 * fdisk_get_first_lba:
 * @cxt: context
 *
 * Returns: first possible LBA on disk for data partitions.
 */
fdisk_sector_t fdisk_get_first_lba(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->first_lba;
}

/**
 * fdisk_set_first_lba:
 * @cxt: fdisk context
 * @lba: first possible logical sector for data
 *
 * It's strongly recommended to use the default library setting. The first LBA
 * is always reset by fdisk_assign_device(), fdisk_override_geometry()
 * and fdisk_reset_alignment(). This is very low level function and library
 * does not check if your setting makes any sense.
 *
 * This function is necessary only when you want to work with very unusual
 * partition tables like GPT protective MBR or hybrid partition tables on
 * bootable media where the first partition may start on very crazy offsets.
 *
 * Note that this function changes only runtime information. It does not update
 * any range in on-disk partition table. For example GPT Header contains First
 * and Last usable LBA fields. These fields are not updated by this function.
 * Be careful.
 *
 * Returns: 0 on success, <0 on error.
 */
fdisk_sector_t fdisk_set_first_lba(struct fdisk_context *cxt, fdisk_sector_t lba)
{
        assert(cxt);
        DBG(CXT, ul_debugobj(cxt, "setting first LBA from %ju to %ju",
                        (uintmax_t) cxt->first_lba, (uintmax_t) lba));
        cxt->first_lba = lba;
        return 0;
}

/**
 * fdisk_get_last_lba:
 * @cxt: fdisk context
 *
 * Note that the device has to be already assigned.
 *
 * Returns: last possible LBA on device
 */
fdisk_sector_t fdisk_get_last_lba(struct fdisk_context *cxt)
{
        return cxt->last_lba;
}

/**
 * fdisk_set_last_lba:
 * @cxt: fdisk context
 * @lba: last possible logical sector
 *
 * It's strongly recommended to use the default library setting. The last LBA
 * is always reset by fdisk_assign_device(), fdisk_override_geometry() and
 * fdisk_reset_alignment().
 *
 * The default is number of sectors on the device, but maybe modified by the
 * current disklabel driver (for example GPT uses the end of disk for backup
 * header, so last_lba is smaller than total number of sectors).
 *
 * Returns: 0 on success, <0 on error.
 */
fdisk_sector_t fdisk_set_last_lba(struct fdisk_context *cxt, fdisk_sector_t lba)
{
        assert(cxt);

        if (lba > cxt->total_sectors - 1 || lba < 1)
                return -ERANGE;
        cxt->last_lba = lba;
        return 0;
}

/**
 * fdisk_set_size_unit:
 * @cxt: fdisk context
 * @unit: FDISK_SIZEUNIT_*
 *
 * Sets unit for SIZE output field (see fdisk_partition_to_string()).
 *
 * Returns: 0 on success, <0 on error.
 */
int fdisk_set_size_unit(struct fdisk_context *cxt, int unit)
{
        assert(cxt);
        cxt->sizeunit = unit;
        return 0;
}

/**
 * fdisk_get_size_unit:
 * @cxt: fdisk context
 *
 * Gets unit for SIZE output field (see fdisk_partition_to_string()).
 *
 * Returns: unit
 */
int fdisk_get_size_unit(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->sizeunit;
}

/**
 * fdisk_get_nsectors:
 * @cxt: context
 *
 * Returns: size of the device in logical sectors.
 */
fdisk_sector_t fdisk_get_nsectors(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->total_sectors;
}

/**
 * fdisk_get_devname:
 * @cxt: context
 *
 * Returns: device name.
 */
const char *fdisk_get_devname(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->dev_path;
}

/**
 * fdisk_get_devno:
 * @cxt: context
 *
 * Returns: device number or zero for non-block devices
 *
 * Since: 2.33
 */
dev_t fdisk_get_devno(struct fdisk_context *cxt)
{
        assert(cxt);
        return S_ISBLK(cxt->dev_st.st_mode) ? cxt->dev_st.st_rdev : 0;
}

/**
 * fdisk_get_devmodel:
 * @cxt: context
 *
 * Returns: device model string or NULL.
 *
 * Since: 2.33
 */
#ifdef __linux__
const char *fdisk_get_devmodel(struct fdisk_context *cxt)
{
        assert(cxt);

        if (cxt->dev_model_probed)
                return cxt->dev_model;

        if (fdisk_get_devno(cxt)) {
                struct path_cxt *pc = ul_new_sysfs_path(fdisk_get_devno(cxt), NULL, NULL);

                if (pc) {
                        ul_path_read_string(pc, &cxt->dev_model, "device/model");
                        ul_unref_path(pc);
                }
        }
        cxt->dev_model_probed = 1;
        return cxt->dev_model;
}
#else
const char *fdisk_get_devmodel(struct fdisk_context *cxt __attribute__((__unused__)))
{
        return NULL;
}
#endif

/**
 * fdisk_get_devfd:
 * @cxt: context
 *
 * Returns: device file descriptor.
 */
int fdisk_get_devfd(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->dev_fd;
}

/**
 * fdisk_get_geom_heads:
 * @cxt: context
 *
 * Returns: number of geometry heads.
 */
unsigned int fdisk_get_geom_heads(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->geom.heads;
}
/**
 * fdisk_get_geom_sectors:
 * @cxt: context
 *
 * Returns: number of geometry sectors.
 */
fdisk_sector_t fdisk_get_geom_sectors(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->geom.sectors;

}

/**
 * fdisk_get_geom_cylinders:
 * @cxt: context
 *
 * Returns: number of geometry cylinders
 */
fdisk_sector_t fdisk_get_geom_cylinders(struct fdisk_context *cxt)
{
        assert(cxt);
        return cxt->geom.cylinders;
}

int fdisk_missing_geometry(struct fdisk_context *cxt)
{
        int rc;

        if (!cxt || !cxt->label)
                return 0;

        rc = (fdisk_label_require_geometry(cxt->label) &&
                    (!cxt->geom.heads || !cxt->geom.sectors
                                      || !cxt->geom.cylinders));

        if (rc && !fdisk_is_listonly(cxt))
                fdisk_warnx(cxt, _("Incomplete geometry setting."));

        return rc;
}