Logo Search packages:      
Sourcecode: linux version File versions  Download package

dm-ioctl.c

/*
 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
 * Copyright (C) 2004 - 2006 Red Hat, Inc. All rights reserved.
 *
 * This file is released under the GPL.
 */

#include "dm.h"

#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/dm-ioctl.h>
#include <linux/hdreg.h>

#include <asm/uaccess.h>

#define DM_MSG_PREFIX "ioctl"
#define DM_DRIVER_EMAIL "dm-devel@redhat.com"

/*-----------------------------------------------------------------
 * The ioctl interface needs to be able to look up devices by
 * name or uuid.
 *---------------------------------------------------------------*/
struct hash_cell {
      struct list_head name_list;
      struct list_head uuid_list;

      char *name;
      char *uuid;
      struct mapped_device *md;
      struct dm_table *new_map;
};

struct vers_iter {
    size_t param_size;
    struct dm_target_versions *vers, *old_vers;
    char *end;
    uint32_t flags;
};


#define NUM_BUCKETS 64
#define MASK_BUCKETS (NUM_BUCKETS - 1)
static struct list_head _name_buckets[NUM_BUCKETS];
static struct list_head _uuid_buckets[NUM_BUCKETS];

static void dm_hash_remove_all(int keep_open_devices);

/*
 * Guards access to both hash tables.
 */
static DECLARE_RWSEM(_hash_lock);

static void init_buckets(struct list_head *buckets)
{
      unsigned int i;

      for (i = 0; i < NUM_BUCKETS; i++)
            INIT_LIST_HEAD(buckets + i);
}

static int dm_hash_init(void)
{
      init_buckets(_name_buckets);
      init_buckets(_uuid_buckets);
      return 0;
}

static void dm_hash_exit(void)
{
      dm_hash_remove_all(0);
}

/*-----------------------------------------------------------------
 * Hash function:
 * We're not really concerned with the str hash function being
 * fast since it's only used by the ioctl interface.
 *---------------------------------------------------------------*/
static unsigned int hash_str(const char *str)
{
      const unsigned int hash_mult = 2654435387U;
      unsigned int h = 0;

      while (*str)
            h = (h + (unsigned int) *str++) * hash_mult;

      return h & MASK_BUCKETS;
}

/*-----------------------------------------------------------------
 * Code for looking up a device by name
 *---------------------------------------------------------------*/
static struct hash_cell *__get_name_cell(const char *str)
{
      struct hash_cell *hc;
      unsigned int h = hash_str(str);

      list_for_each_entry (hc, _name_buckets + h, name_list)
            if (!strcmp(hc->name, str)) {
                  dm_get(hc->md);
                  return hc;
            }

      return NULL;
}

static struct hash_cell *__get_uuid_cell(const char *str)
{
      struct hash_cell *hc;
      unsigned int h = hash_str(str);

      list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
            if (!strcmp(hc->uuid, str)) {
                  dm_get(hc->md);
                  return hc;
            }

      return NULL;
}

/*-----------------------------------------------------------------
 * Inserting, removing and renaming a device.
 *---------------------------------------------------------------*/
static struct hash_cell *alloc_cell(const char *name, const char *uuid,
                            struct mapped_device *md)
{
      struct hash_cell *hc;

      hc = kmalloc(sizeof(*hc), GFP_KERNEL);
      if (!hc)
            return NULL;

      hc->name = kstrdup(name, GFP_KERNEL);
      if (!hc->name) {
            kfree(hc);
            return NULL;
      }

      if (!uuid)
            hc->uuid = NULL;

      else {
            hc->uuid = kstrdup(uuid, GFP_KERNEL);
            if (!hc->uuid) {
                  kfree(hc->name);
                  kfree(hc);
                  return NULL;
            }
      }

      INIT_LIST_HEAD(&hc->name_list);
      INIT_LIST_HEAD(&hc->uuid_list);
      hc->md = md;
      hc->new_map = NULL;
      return hc;
}

static void free_cell(struct hash_cell *hc)
{
      if (hc) {
            kfree(hc->name);
            kfree(hc->uuid);
            kfree(hc);
      }
}

/*
 * The kdev_t and uuid of a device can never change once it is
 * initially inserted.
 */
static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
{
      struct hash_cell *cell, *hc;

      /*
       * Allocate the new cells.
       */
      cell = alloc_cell(name, uuid, md);
      if (!cell)
            return -ENOMEM;

      /*
       * Insert the cell into both hash tables.
       */
      down_write(&_hash_lock);
      hc = __get_name_cell(name);
      if (hc) {
            dm_put(hc->md);
            goto bad;
      }

      list_add(&cell->name_list, _name_buckets + hash_str(name));

      if (uuid) {
            hc = __get_uuid_cell(uuid);
            if (hc) {
                  list_del(&cell->name_list);
                  dm_put(hc->md);
                  goto bad;
            }
            list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
      }
      dm_get(md);
      dm_set_mdptr(md, cell);
      up_write(&_hash_lock);

      return 0;

 bad:
      up_write(&_hash_lock);
      free_cell(cell);
      return -EBUSY;
}

static void __hash_remove(struct hash_cell *hc)
{
      struct dm_table *table;

      /* remove from the dev hash */
      list_del(&hc->uuid_list);
      list_del(&hc->name_list);
      dm_set_mdptr(hc->md, NULL);

      table = dm_get_table(hc->md);
      if (table) {
            dm_table_event(table);
            dm_table_put(table);
      }

      if (hc->new_map)
            dm_table_put(hc->new_map);
      dm_put(hc->md);
      free_cell(hc);
}

static void dm_hash_remove_all(int keep_open_devices)
{
      int i, dev_skipped, dev_removed;
      struct hash_cell *hc;
      struct list_head *tmp, *n;

      down_write(&_hash_lock);

retry:
      dev_skipped = dev_removed = 0;
      for (i = 0; i < NUM_BUCKETS; i++) {
            list_for_each_safe (tmp, n, _name_buckets + i) {
                  hc = list_entry(tmp, struct hash_cell, name_list);

                  if (keep_open_devices &&
                      dm_lock_for_deletion(hc->md)) {
                        dev_skipped++;
                        continue;
                  }
                  __hash_remove(hc);
                  dev_removed = 1;
            }
      }

      /*
       * Some mapped devices may be using other mapped devices, so if any
       * still exist, repeat until we make no further progress.
       */
      if (dev_skipped) {
            if (dev_removed)
                  goto retry;

            DMWARN("remove_all left %d open device(s)", dev_skipped);
      }

      up_write(&_hash_lock);
}

static int dm_hash_rename(const char *old, const char *new)
{
      char *new_name, *old_name;
      struct hash_cell *hc;
      struct dm_table *table;

      /*
       * duplicate new.
       */
      new_name = kstrdup(new, GFP_KERNEL);
      if (!new_name)
            return -ENOMEM;

      down_write(&_hash_lock);

      /*
       * Is new free ?
       */
      hc = __get_name_cell(new);
      if (hc) {
            DMWARN("asked to rename to an already existing name %s -> %s",
                   old, new);
            dm_put(hc->md);
            up_write(&_hash_lock);
            kfree(new_name);
            return -EBUSY;
      }

      /*
       * Is there such a device as 'old' ?
       */
      hc = __get_name_cell(old);
      if (!hc) {
            DMWARN("asked to rename a non existent device %s -> %s",
                   old, new);
            up_write(&_hash_lock);
            kfree(new_name);
            return -ENXIO;
      }

      /*
       * rename and move the name cell.
       */
      list_del(&hc->name_list);
      old_name = hc->name;
      hc->name = new_name;
      list_add(&hc->name_list, _name_buckets + hash_str(new_name));

      /*
       * Wake up any dm event waiters.
       */
      table = dm_get_table(hc->md);
      if (table) {
            dm_table_event(table);
            dm_table_put(table);
      }

      dm_kobject_uevent(hc->md);

      dm_put(hc->md);
      up_write(&_hash_lock);
      kfree(old_name);
      return 0;
}

/*-----------------------------------------------------------------
 * Implementation of the ioctl commands
 *---------------------------------------------------------------*/
/*
 * All the ioctl commands get dispatched to functions with this
 * prototype.
 */
typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);

static int remove_all(struct dm_ioctl *param, size_t param_size)
{
      dm_hash_remove_all(1);
      param->data_size = 0;
      return 0;
}

/*
 * Round up the ptr to an 8-byte boundary.
 */
#define ALIGN_MASK 7
static inline void *align_ptr(void *ptr)
{
      return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
}

/*
 * Retrieves the data payload buffer from an already allocated
 * struct dm_ioctl.
 */
static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
                         size_t *len)
{
      param->data_start = align_ptr(param + 1) - (void *) param;

      if (param->data_start < param_size)
            *len = param_size - param->data_start;
      else
            *len = 0;

      return ((void *) param) + param->data_start;
}

static int list_devices(struct dm_ioctl *param, size_t param_size)
{
      unsigned int i;
      struct hash_cell *hc;
      size_t len, needed = 0;
      struct gendisk *disk;
      struct dm_name_list *nl, *old_nl = NULL;

      down_write(&_hash_lock);

      /*
       * Loop through all the devices working out how much
       * space we need.
       */
      for (i = 0; i < NUM_BUCKETS; i++) {
            list_for_each_entry (hc, _name_buckets + i, name_list) {
                  needed += sizeof(struct dm_name_list);
                  needed += strlen(hc->name) + 1;
                  needed += ALIGN_MASK;
            }
      }

      /*
       * Grab our output buffer.
       */
      nl = get_result_buffer(param, param_size, &len);
      if (len < needed) {
            param->flags |= DM_BUFFER_FULL_FLAG;
            goto out;
      }
      param->data_size = param->data_start + needed;

      nl->dev = 0;      /* Flags no data */

      /*
       * Now loop through filling out the names.
       */
      for (i = 0; i < NUM_BUCKETS; i++) {
            list_for_each_entry (hc, _name_buckets + i, name_list) {
                  if (old_nl)
                        old_nl->next = (uint32_t) ((void *) nl -
                                             (void *) old_nl);
                  disk = dm_disk(hc->md);
                  nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
                  nl->next = 0;
                  strcpy(nl->name, hc->name);

                  old_nl = nl;
                  nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
            }
      }

 out:
      up_write(&_hash_lock);
      return 0;
}

static void list_version_get_needed(struct target_type *tt, void *needed_param)
{
    size_t *needed = needed_param;

    *needed += sizeof(struct dm_target_versions);
    *needed += strlen(tt->name);
    *needed += ALIGN_MASK;
}

static void list_version_get_info(struct target_type *tt, void *param)
{
    struct vers_iter *info = param;

    /* Check space - it might have changed since the first iteration */
    if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
      info->end) {

      info->flags = DM_BUFFER_FULL_FLAG;
      return;
    }

    if (info->old_vers)
      info->old_vers->next = (uint32_t) ((void *)info->vers -
                                 (void *)info->old_vers);
    info->vers->version[0] = tt->version[0];
    info->vers->version[1] = tt->version[1];
    info->vers->version[2] = tt->version[2];
    info->vers->next = 0;
    strcpy(info->vers->name, tt->name);

    info->old_vers = info->vers;
    info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
}

static int list_versions(struct dm_ioctl *param, size_t param_size)
{
      size_t len, needed = 0;
      struct dm_target_versions *vers;
      struct vers_iter iter_info;

      /*
       * Loop through all the devices working out how much
       * space we need.
       */
      dm_target_iterate(list_version_get_needed, &needed);

      /*
       * Grab our output buffer.
       */
      vers = get_result_buffer(param, param_size, &len);
      if (len < needed) {
            param->flags |= DM_BUFFER_FULL_FLAG;
            goto out;
      }
      param->data_size = param->data_start + needed;

      iter_info.param_size = param_size;
      iter_info.old_vers = NULL;
      iter_info.vers = vers;
      iter_info.flags = 0;
      iter_info.end = (char *)vers+len;

      /*
       * Now loop through filling out the names & versions.
       */
      dm_target_iterate(list_version_get_info, &iter_info);
      param->flags |= iter_info.flags;

 out:
      return 0;
}



static int check_name(const char *name)
{
      if (strchr(name, '/')) {
            DMWARN("invalid device name");
            return -EINVAL;
      }

      return 0;
}

/*
 * Fills in a dm_ioctl structure, ready for sending back to
 * userland.
 */
static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
{
      struct gendisk *disk = dm_disk(md);
      struct dm_table *table;

      param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
                    DM_ACTIVE_PRESENT_FLAG);

      if (dm_suspended(md))
            param->flags |= DM_SUSPEND_FLAG;

      param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));

      /*
       * Yes, this will be out of date by the time it gets back
       * to userland, but it is still very useful for
       * debugging.
       */
      param->open_count = dm_open_count(md);

      if (disk->policy)
            param->flags |= DM_READONLY_FLAG;

      param->event_nr = dm_get_event_nr(md);

      table = dm_get_table(md);
      if (table) {
            param->flags |= DM_ACTIVE_PRESENT_FLAG;
            param->target_count = dm_table_get_num_targets(table);
            dm_table_put(table);
      } else
            param->target_count = 0;

      return 0;
}

static int dev_create(struct dm_ioctl *param, size_t param_size)
{
      int r, m = DM_ANY_MINOR;
      struct mapped_device *md;

      r = check_name(param->name);
      if (r)
            return r;

      if (param->flags & DM_PERSISTENT_DEV_FLAG)
            m = MINOR(huge_decode_dev(param->dev));

      r = dm_create(m, &md);
      if (r)
            return r;

      r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
      if (r) {
            dm_put(md);
            return r;
      }

      param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

      r = __dev_status(md, param);
      dm_put(md);

      return r;
}

/*
 * Always use UUID for lookups if it's present, otherwise use name or dev.
 */
static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
{
      struct mapped_device *md;
      void *mdptr = NULL;

      if (*param->uuid)
            return __get_uuid_cell(param->uuid);

      if (*param->name)
            return __get_name_cell(param->name);

      md = dm_get_md(huge_decode_dev(param->dev));
      if (!md)
            goto out;

      mdptr = dm_get_mdptr(md);
      if (!mdptr)
            dm_put(md);

out:
      return mdptr;
}

static struct mapped_device *find_device(struct dm_ioctl *param)
{
      struct hash_cell *hc;
      struct mapped_device *md = NULL;

      down_read(&_hash_lock);
      hc = __find_device_hash_cell(param);
      if (hc) {
            md = hc->md;

            /*
             * Sneakily write in both the name and the uuid
             * while we have the cell.
             */
            strncpy(param->name, hc->name, sizeof(param->name));
            if (hc->uuid)
                  strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
            else
                  param->uuid[0] = '\0';

            if (hc->new_map)
                  param->flags |= DM_INACTIVE_PRESENT_FLAG;
            else
                  param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
      }
      up_read(&_hash_lock);

      return md;
}

static int dev_remove(struct dm_ioctl *param, size_t param_size)
{
      struct hash_cell *hc;
      struct mapped_device *md;
      int r;

      down_write(&_hash_lock);
      hc = __find_device_hash_cell(param);

      if (!hc) {
            DMWARN("device doesn't appear to be in the dev hash table.");
            up_write(&_hash_lock);
            return -ENXIO;
      }

      md = hc->md;

      /*
       * Ensure the device is not open and nothing further can open it.
       */
      r = dm_lock_for_deletion(md);
      if (r) {
            DMWARN("unable to remove open device %s", hc->name);
            up_write(&_hash_lock);
            dm_put(md);
            return r;
      }

      __hash_remove(hc);
      up_write(&_hash_lock);
      dm_put(md);
      param->data_size = 0;
      return 0;
}

/*
 * Check a string doesn't overrun the chunk of
 * memory we copied from userland.
 */
static int invalid_str(char *str, void *end)
{
      while ((void *) str < end)
            if (!*str++)
                  return 0;

      return -EINVAL;
}

static int dev_rename(struct dm_ioctl *param, size_t param_size)
{
      int r;
      char *new_name = (char *) param + param->data_start;

      if (new_name < (char *) param->data ||
          invalid_str(new_name, (void *) param + param_size)) {
            DMWARN("Invalid new logical volume name supplied.");
            return -EINVAL;
      }

      r = check_name(new_name);
      if (r)
            return r;

      param->data_size = 0;
      return dm_hash_rename(param->name, new_name);
}

static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
{
      int r = -EINVAL, x;
      struct mapped_device *md;
      struct hd_geometry geometry;
      unsigned long indata[4];
      char *geostr = (char *) param + param->data_start;

      md = find_device(param);
      if (!md)
            return -ENXIO;

      if (geostr < (char *) param->data ||
          invalid_str(geostr, (void *) param + param_size)) {
            DMWARN("Invalid geometry supplied.");
            goto out;
      }

      x = sscanf(geostr, "%lu %lu %lu %lu", indata,
               indata + 1, indata + 2, indata + 3);

      if (x != 4) {
            DMWARN("Unable to interpret geometry settings.");
            goto out;
      }

      if (indata[0] > 65535 || indata[1] > 255 ||
          indata[2] > 255 || indata[3] > ULONG_MAX) {
            DMWARN("Geometry exceeds range limits.");
            goto out;
      }

      geometry.cylinders = indata[0];
      geometry.heads = indata[1];
      geometry.sectors = indata[2];
      geometry.start = indata[3];

      r = dm_set_geometry(md, &geometry);
      if (!r)
            r = __dev_status(md, param);

      param->data_size = 0;

out:
      dm_put(md);
      return r;
}

static int do_suspend(struct dm_ioctl *param)
{
      int r = 0;
      unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
      struct mapped_device *md;

      md = find_device(param);
      if (!md)
            return -ENXIO;

      if (param->flags & DM_SKIP_LOCKFS_FLAG)
            suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
      if (param->flags & DM_NOFLUSH_FLAG)
            suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;

      if (!dm_suspended(md))
            r = dm_suspend(md, suspend_flags);

      if (!r)
            r = __dev_status(md, param);

      dm_put(md);
      return r;
}

static int do_resume(struct dm_ioctl *param)
{
      int r = 0;
      unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
      struct hash_cell *hc;
      struct mapped_device *md;
      struct dm_table *new_map;

      down_write(&_hash_lock);

      hc = __find_device_hash_cell(param);
      if (!hc) {
            DMWARN("device doesn't appear to be in the dev hash table.");
            up_write(&_hash_lock);
            return -ENXIO;
      }

      md = hc->md;

      new_map = hc->new_map;
      hc->new_map = NULL;
      param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

      up_write(&_hash_lock);

      /* Do we need to load a new map ? */
      if (new_map) {
            /* Suspend if it isn't already suspended */
            if (param->flags & DM_SKIP_LOCKFS_FLAG)
                  suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
            if (param->flags & DM_NOFLUSH_FLAG)
                  suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
            if (!dm_suspended(md))
                  dm_suspend(md, suspend_flags);

            r = dm_swap_table(md, new_map);
            if (r) {
                  dm_put(md);
                  dm_table_put(new_map);
                  return r;
            }

            if (dm_table_get_mode(new_map) & FMODE_WRITE)
                  set_disk_ro(dm_disk(md), 0);
            else
                  set_disk_ro(dm_disk(md), 1);

            dm_table_put(new_map);
      }

      if (dm_suspended(md))
            r = dm_resume(md);

      if (!r)
            r = __dev_status(md, param);

      dm_put(md);
      return r;
}

/*
 * Set or unset the suspension state of a device.
 * If the device already is in the requested state we just return its status.
 */
static int dev_suspend(struct dm_ioctl *param, size_t param_size)
{
      if (param->flags & DM_SUSPEND_FLAG)
            return do_suspend(param);

      return do_resume(param);
}

/*
 * Copies device info back to user space, used by
 * the create and info ioctls.
 */
static int dev_status(struct dm_ioctl *param, size_t param_size)
{
      int r;
      struct mapped_device *md;

      md = find_device(param);
      if (!md)
            return -ENXIO;

      r = __dev_status(md, param);
      dm_put(md);
      return r;
}

/*
 * Build up the status struct for each target
 */
static void retrieve_status(struct dm_table *table,
                      struct dm_ioctl *param, size_t param_size)
{
      unsigned int i, num_targets;
      struct dm_target_spec *spec;
      char *outbuf, *outptr;
      status_type_t type;
      size_t remaining, len, used = 0;

      outptr = outbuf = get_result_buffer(param, param_size, &len);

      if (param->flags & DM_STATUS_TABLE_FLAG)
            type = STATUSTYPE_TABLE;
      else
            type = STATUSTYPE_INFO;

      /* Get all the target info */
      num_targets = dm_table_get_num_targets(table);
      for (i = 0; i < num_targets; i++) {
            struct dm_target *ti = dm_table_get_target(table, i);

            remaining = len - (outptr - outbuf);
            if (remaining <= sizeof(struct dm_target_spec)) {
                  param->flags |= DM_BUFFER_FULL_FLAG;
                  break;
            }

            spec = (struct dm_target_spec *) outptr;

            spec->status = 0;
            spec->sector_start = ti->begin;
            spec->length = ti->len;
            strncpy(spec->target_type, ti->type->name,
                  sizeof(spec->target_type));

            outptr += sizeof(struct dm_target_spec);
            remaining = len - (outptr - outbuf);
            if (remaining <= 0) {
                  param->flags |= DM_BUFFER_FULL_FLAG;
                  break;
            }

            /* Get the status/table string from the target driver */
            if (ti->type->status) {
                  if (ti->type->status(ti, type, outptr, remaining)) {
                        param->flags |= DM_BUFFER_FULL_FLAG;
                        break;
                  }
            } else
                  outptr[0] = '\0';

            outptr += strlen(outptr) + 1;
            used = param->data_start + (outptr - outbuf);

            outptr = align_ptr(outptr);
            spec->next = outptr - outbuf;
      }

      if (used)
            param->data_size = used;

      param->target_count = num_targets;
}

/*
 * Wait for a device to report an event
 */
static int dev_wait(struct dm_ioctl *param, size_t param_size)
{
      int r;
      struct mapped_device *md;
      struct dm_table *table;

      md = find_device(param);
      if (!md)
            return -ENXIO;

      /*
       * Wait for a notification event
       */
      if (dm_wait_event(md, param->event_nr)) {
            r = -ERESTARTSYS;
            goto out;
      }

      /*
       * The userland program is going to want to know what
       * changed to trigger the event, so we may as well tell
       * him and save an ioctl.
       */
      r = __dev_status(md, param);
      if (r)
            goto out;

      table = dm_get_table(md);
      if (table) {
            retrieve_status(table, param, param_size);
            dm_table_put(table);
      }

 out:
      dm_put(md);
      return r;
}

static inline int get_mode(struct dm_ioctl *param)
{
      int mode = FMODE_READ | FMODE_WRITE;

      if (param->flags & DM_READONLY_FLAG)
            mode = FMODE_READ;

      return mode;
}

static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
                   struct dm_target_spec **spec, char **target_params)
{
      *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
      *target_params = (char *) (*spec + 1);

      if (*spec < (last + 1))
            return -EINVAL;

      return invalid_str(*target_params, end);
}

static int populate_table(struct dm_table *table,
                    struct dm_ioctl *param, size_t param_size)
{
      int r;
      unsigned int i = 0;
      struct dm_target_spec *spec = (struct dm_target_spec *) param;
      uint32_t next = param->data_start;
      void *end = (void *) param + param_size;
      char *target_params;

      if (!param->target_count) {
            DMWARN("populate_table: no targets specified");
            return -EINVAL;
      }

      for (i = 0; i < param->target_count; i++) {

            r = next_target(spec, next, end, &spec, &target_params);
            if (r) {
                  DMWARN("unable to find target");
                  return r;
            }

            r = dm_table_add_target(table, spec->target_type,
                              (sector_t) spec->sector_start,
                              (sector_t) spec->length,
                              target_params);
            if (r) {
                  DMWARN("error adding target to table");
                  return r;
            }

            next = spec->next;
      }

      return dm_table_complete(table);
}

static int table_load(struct dm_ioctl *param, size_t param_size)
{
      int r;
      struct hash_cell *hc;
      struct dm_table *t;
      struct mapped_device *md;

      md = find_device(param);
      if (!md)
            return -ENXIO;

      r = dm_table_create(&t, get_mode(param), param->target_count, md);
      if (r)
            goto out;

      r = populate_table(t, param, param_size);
      if (r) {
            dm_table_put(t);
            goto out;
      }

      down_write(&_hash_lock);
      hc = dm_get_mdptr(md);
      if (!hc || hc->md != md) {
            DMWARN("device has been removed from the dev hash table.");
            dm_table_put(t);
            up_write(&_hash_lock);
            r = -ENXIO;
            goto out;
      }

      if (hc->new_map)
            dm_table_put(hc->new_map);
      hc->new_map = t;
      up_write(&_hash_lock);

      param->flags |= DM_INACTIVE_PRESENT_FLAG;
      r = __dev_status(md, param);

out:
      dm_put(md);

      return r;
}

static int table_clear(struct dm_ioctl *param, size_t param_size)
{
      int r;
      struct hash_cell *hc;
      struct mapped_device *md;

      down_write(&_hash_lock);

      hc = __find_device_hash_cell(param);
      if (!hc) {
            DMWARN("device doesn't appear to be in the dev hash table.");
            up_write(&_hash_lock);
            return -ENXIO;
      }

      if (hc->new_map) {
            dm_table_put(hc->new_map);
            hc->new_map = NULL;
      }

      param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

      r = __dev_status(hc->md, param);
      md = hc->md;
      up_write(&_hash_lock);
      dm_put(md);
      return r;
}

/*
 * Retrieves a list of devices used by a particular dm device.
 */
static void retrieve_deps(struct dm_table *table,
                    struct dm_ioctl *param, size_t param_size)
{
      unsigned int count = 0;
      struct list_head *tmp;
      size_t len, needed;
      struct dm_dev *dd;
      struct dm_target_deps *deps;

      deps = get_result_buffer(param, param_size, &len);

      /*
       * Count the devices.
       */
      list_for_each (tmp, dm_table_get_devices(table))
            count++;

      /*
       * Check we have enough space.
       */
      needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
      if (len < needed) {
            param->flags |= DM_BUFFER_FULL_FLAG;
            return;
      }

      /*
       * Fill in the devices.
       */
      deps->count = count;
      count = 0;
      list_for_each_entry (dd, dm_table_get_devices(table), list)
            deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);

      param->data_size = param->data_start + needed;
}

static int table_deps(struct dm_ioctl *param, size_t param_size)
{
      int r = 0;
      struct mapped_device *md;
      struct dm_table *table;

      md = find_device(param);
      if (!md)
            return -ENXIO;

      r = __dev_status(md, param);
      if (r)
            goto out;

      table = dm_get_table(md);
      if (table) {
            retrieve_deps(table, param, param_size);
            dm_table_put(table);
      }

 out:
      dm_put(md);
      return r;
}

/*
 * Return the status of a device as a text string for each
 * target.
 */
static int table_status(struct dm_ioctl *param, size_t param_size)
{
      int r;
      struct mapped_device *md;
      struct dm_table *table;

      md = find_device(param);
      if (!md)
            return -ENXIO;

      r = __dev_status(md, param);
      if (r)
            goto out;

      table = dm_get_table(md);
      if (table) {
            retrieve_status(table, param, param_size);
            dm_table_put(table);
      }

 out:
      dm_put(md);
      return r;
}

/*
 * Pass a message to the target that's at the supplied device offset.
 */
static int target_message(struct dm_ioctl *param, size_t param_size)
{
      int r, argc;
      char **argv;
      struct mapped_device *md;
      struct dm_table *table;
      struct dm_target *ti;
      struct dm_target_msg *tmsg = (void *) param + param->data_start;

      md = find_device(param);
      if (!md)
            return -ENXIO;

      r = __dev_status(md, param);
      if (r)
            goto out;

      if (tmsg < (struct dm_target_msg *) param->data ||
          invalid_str(tmsg->message, (void *) param + param_size)) {
            DMWARN("Invalid target message parameters.");
            r = -EINVAL;
            goto out;
      }

      r = dm_split_args(&argc, &argv, tmsg->message);
      if (r) {
            DMWARN("Failed to split target message parameters");
            goto out;
      }

      table = dm_get_table(md);
      if (!table)
            goto out_argv;

      ti = dm_table_find_target(table, tmsg->sector);
      if (!dm_target_is_valid(ti)) {
            DMWARN("Target message sector outside device.");
            r = -EINVAL;
      } else if (ti->type->message)
            r = ti->type->message(ti, argc, argv);
      else {
            DMWARN("Target type does not support messages");
            r = -EINVAL;
      }

      dm_table_put(table);
 out_argv:
      kfree(argv);
 out:
      param->data_size = 0;
      dm_put(md);
      return r;
}

/*-----------------------------------------------------------------
 * Implementation of open/close/ioctl on the special char
 * device.
 *---------------------------------------------------------------*/
static ioctl_fn lookup_ioctl(unsigned int cmd)
{
      static struct {
            int cmd;
            ioctl_fn fn;
      } _ioctls[] = {
            {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
            {DM_REMOVE_ALL_CMD, remove_all},
            {DM_LIST_DEVICES_CMD, list_devices},

            {DM_DEV_CREATE_CMD, dev_create},
            {DM_DEV_REMOVE_CMD, dev_remove},
            {DM_DEV_RENAME_CMD, dev_rename},
            {DM_DEV_SUSPEND_CMD, dev_suspend},
            {DM_DEV_STATUS_CMD, dev_status},
            {DM_DEV_WAIT_CMD, dev_wait},

            {DM_TABLE_LOAD_CMD, table_load},
            {DM_TABLE_CLEAR_CMD, table_clear},
            {DM_TABLE_DEPS_CMD, table_deps},
            {DM_TABLE_STATUS_CMD, table_status},

            {DM_LIST_VERSIONS_CMD, list_versions},

            {DM_TARGET_MSG_CMD, target_message},
            {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
      };

      return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
}

/*
 * As well as checking the version compatibility this always
 * copies the kernel interface version out.
 */
static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
{
      uint32_t version[3];
      int r = 0;

      if (copy_from_user(version, user->version, sizeof(version)))
            return -EFAULT;

      if ((DM_VERSION_MAJOR != version[0]) ||
          (DM_VERSION_MINOR < version[1])) {
            DMWARN("ioctl interface mismatch: "
                   "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
                   DM_VERSION_MAJOR, DM_VERSION_MINOR,
                   DM_VERSION_PATCHLEVEL,
                   version[0], version[1], version[2], cmd);
            r = -EINVAL;
      }

      /*
       * Fill in the kernel version.
       */
      version[0] = DM_VERSION_MAJOR;
      version[1] = DM_VERSION_MINOR;
      version[2] = DM_VERSION_PATCHLEVEL;
      if (copy_to_user(user->version, version, sizeof(version)))
            return -EFAULT;

      return r;
}

static void free_params(struct dm_ioctl *param)
{
      vfree(param);
}

static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
{
      struct dm_ioctl tmp, *dmi;

      if (copy_from_user(&tmp, user, sizeof(tmp)))
            return -EFAULT;

      if (tmp.data_size < sizeof(tmp))
            return -EINVAL;

      dmi = vmalloc(tmp.data_size);
      if (!dmi)
            return -ENOMEM;

      if (copy_from_user(dmi, user, tmp.data_size)) {
            vfree(dmi);
            return -EFAULT;
      }

      *param = dmi;
      return 0;
}

static int validate_params(uint cmd, struct dm_ioctl *param)
{
      /* Always clear this flag */
      param->flags &= ~DM_BUFFER_FULL_FLAG;

      /* Ignores parameters */
      if (cmd == DM_REMOVE_ALL_CMD ||
          cmd == DM_LIST_DEVICES_CMD ||
          cmd == DM_LIST_VERSIONS_CMD)
            return 0;

      if ((cmd == DM_DEV_CREATE_CMD)) {
            if (!*param->name) {
                  DMWARN("name not supplied when creating device");
                  return -EINVAL;
            }
      } else if ((*param->uuid && *param->name)) {
            DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
            return -EINVAL;
      }

      /* Ensure strings are terminated */
      param->name[DM_NAME_LEN - 1] = '\0';
      param->uuid[DM_UUID_LEN - 1] = '\0';

      return 0;
}

static int ctl_ioctl(struct inode *inode, struct file *file,
                 uint command, ulong u)
{
      int r = 0;
      unsigned int cmd;
      struct dm_ioctl *param;
      struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
      ioctl_fn fn = NULL;
      size_t param_size;

      /* only root can play with this */
      if (!capable(CAP_SYS_ADMIN))
            return -EACCES;

      if (_IOC_TYPE(command) != DM_IOCTL)
            return -ENOTTY;

      cmd = _IOC_NR(command);

      /*
       * Check the interface version passed in.  This also
       * writes out the kernel's interface version.
       */
      r = check_version(cmd, user);
      if (r)
            return r;

      /*
       * Nothing more to do for the version command.
       */
      if (cmd == DM_VERSION_CMD)
            return 0;

      fn = lookup_ioctl(cmd);
      if (!fn) {
            DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
            return -ENOTTY;
      }

      /*
       * Trying to avoid low memory issues when a device is
       * suspended.
       */
      current->flags |= PF_MEMALLOC;

      /*
       * Copy the parameters into kernel space.
       */
      r = copy_params(user, &param);

      current->flags &= ~PF_MEMALLOC;

      if (r)
            return r;

      r = validate_params(cmd, param);
      if (r)
            goto out;

      param_size = param->data_size;
      param->data_size = sizeof(*param);
      r = fn(param, param_size);

      /*
       * Copy the results back to userland.
       */
      if (!r && copy_to_user(user, param, param->data_size))
            r = -EFAULT;

 out:
      free_params(param);
      return r;
}

static const struct file_operations _ctl_fops = {
      .ioctl       = ctl_ioctl,
      .owner       = THIS_MODULE,
};

static struct miscdevice _dm_misc = {
      .minor            = MISC_DYNAMIC_MINOR,
      .name             = DM_NAME,
      .fops             = &_ctl_fops
};

/*
 * Create misc character device and link to DM_DIR/control.
 */
int __init dm_interface_init(void)
{
      int r;

      r = dm_hash_init();
      if (r)
            return r;

      r = misc_register(&_dm_misc);
      if (r) {
            DMERR("misc_register failed for control device");
            dm_hash_exit();
            return r;
      }

      DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
             DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
             DM_DRIVER_EMAIL);
      return 0;
}

void dm_interface_exit(void)
{
      if (misc_deregister(&_dm_misc) < 0)
            DMERR("misc_deregister failed for control device");

      dm_hash_exit();
}

/**
 * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers
 * @md: Pointer to mapped_device
 * @name: Buffer (size DM_NAME_LEN) for name
 * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined
 */
int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
{
      int r = 0;
      struct hash_cell *hc;

      if (!md)
            return -ENXIO;

      dm_get(md);
      down_read(&_hash_lock);
      hc = dm_get_mdptr(md);
      if (!hc || hc->md != md) {
            r = -ENXIO;
            goto out;
      }

      strcpy(name, hc->name);
      strcpy(uuid, hc->uuid ? : "");

out:
      up_read(&_hash_lock);
      dm_put(md);

      return r;
}

Generated by  Doxygen 1.6.0   Back to index