/src/lvm2/libdm/ioctl/libdm-iface.c

Source
/*
 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
 * Copyright (C) 2004-2013 Red Hat, Inc. All rights reserved.
 *
 * This file is part of the device-mapper userspace tools.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU Lesser General Public License v.2.1.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libdm/misc/dmlib.h"
#include "libdm-targets.h"
#include "libdm/libdm-common.h"

#include <stddef.h>
#include <fcntl.h>
#include <dirent.h>
#include <pthread.h>
#include <sys/ioctl.h>
#include <sys/utsname.h>
#include <limits.h>

#ifdef __linux__
#  include "libdm/misc/kdev_t.h"
#  include <linux/limits.h>
#else
#  define MAJOR(x) major((x))
#  define MINOR(x) minor((x))
#  define MKDEV(x,y) makedev(((dev_t)x),((dev_t)y))
#endif

#include "libdm/misc/dm-ioctl.h"

/*
 * Ensure build compatibility.
 * The hard-coded versions here are the highest present
 * in the _cmd_data arrays.
 */

#if !((DM_VERSION_MAJOR == 4 && DM_VERSION_MINOR >= 6))
#error The version of dm-ioctl.h included is incompatible.
#endif

/* FIXME This should be exported in device-mapper.h */
#define DM_NAME "device-mapper"

#define PROC_MISC "/proc/misc"
#define PROC_DEVICES "/proc/devices"
#define MISC_NAME "misc"

#define NUMBER_OF_MAJORS 4096

/*
 * Static minor number assigned since kernel version 2.6.36.
 * The original definition is in kernel's include/linux/miscdevice.h.
 * This number is also visible in modules.devname exported by depmod
 * utility (support included in module-init-tools version >= 3.12).
 */
#define MAPPER_CTRL_MINOR 236
#define MISC_MAJOR 10

/* dm major version no for running kernel */
static unsigned _dm_version = DM_VERSION_MAJOR;
static unsigned _dm_version_minor = 0;
static unsigned _dm_version_patchlevel = 0;
static int _dm_warn_inactive_suppress = 0;

/*
 * If the kernel dm driver only supports one major number
 * we store it in _dm_device_major.  Otherwise we indicate
 * which major numbers have been claimed by device-mapper
 * in _dm_bitset.
 */
static unsigned _dm_multiple_major_support = 1;
static dm_bitset_t _dm_bitset = NULL;
static uint32_t _dm_device_major = 0;

static int _control_fd = -1;
static int _hold_control_fd_open = 0;
/* Mutex, not pthread_once: fd can be closed and reopened */
static pthread_mutex_t _control_fd_mutex = PTHREAD_MUTEX_INITIALIZER;
static int _version_ok = 1;
static pthread_once_t _version_once = PTHREAD_ONCE_INIT;
static unsigned _ioctl_buffer_double_factor = 0;
/* Max ioctl buffer: 16KB << 16 = 1GB */
#define DM_IOCTL_BUFFER_MAX_DOUBLINGS 16

/* *INDENT-OFF* */
static const struct cmd_data _cmd_data_v4[] = {
  {"create",  DM_DEV_CREATE,    {4, 0, 0}},
  {"reload",  DM_TABLE_LOAD,    {4, 0, 0}},
  {"remove",  DM_DEV_REMOVE,    {4, 0, 0}},
  {"remove_all",  DM_REMOVE_ALL,    {4, 0, 0}},
  {"suspend", DM_DEV_SUSPEND,   {4, 0, 0}},
  {"resume",  DM_DEV_SUSPEND,   {4, 0, 0}},
  {"info",  DM_DEV_STATUS,    {4, 0, 0}},
  {"deps",  DM_TABLE_DEPS,    {4, 0, 0}},
  {"rename",  DM_DEV_RENAME,    {4, 0, 0}},
  {"version", DM_VERSION,   {4, 0, 0}},
  {"status",  DM_TABLE_STATUS,  {4, 0, 0}},
  {"table", DM_TABLE_STATUS,  {4, 0, 0}},
  {"waitevent", DM_DEV_WAIT,    {4, 0, 0}},
  {"names", DM_LIST_DEVICES,  {4, 0, 0}},
  {"clear", DM_TABLE_CLEAR,   {4, 0, 0}},
  {"mknodes", DM_DEV_STATUS,    {4, 0, 0}},
#ifdef DM_LIST_VERSIONS
  {"versions",  DM_LIST_VERSIONS, {4, 1, 0}},
#endif
#ifdef DM_TARGET_MSG
  {"message", DM_TARGET_MSG,    {4, 2, 0}},
#endif
#ifdef DM_DEV_SET_GEOMETRY
  {"setgeometry", DM_DEV_SET_GEOMETRY,  {4, 6, 0}},
#endif
#ifdef DM_DEV_ARM_POLL
  {"armpoll", DM_DEV_ARM_POLL,  {4, 36, 0}},
#endif
#ifdef DM_GET_TARGET_VERSION
  {"target-version", DM_GET_TARGET_VERSION, {4, 41, 0}},
#endif
};
/* *INDENT-ON* */

/* Validate task type against the command table. */
static int _validate_task_type(struct dm_task *dmt)
{
  if ((unsigned) dmt->type >= DM_ARRAY_SIZE(_cmd_data_v4)) {
    log_error(INTERNAL_ERROR "unknown device-mapper task %d",
        dmt->type);
    return 0;
  }

  return 1;
}

#define ALIGNMENT 8

/* FIXME Rejig library to record & use errno instead */
#ifndef DM_EXISTS_FLAG
#  define DM_EXISTS_FLAG 0x00000004
#endif

static char *_align(char *ptr, unsigned int a)
{
  register unsigned long agn = --a;

  return (char *) (((unsigned long) ptr + agn) & ~agn);
}

static unsigned _kernel_major = 0;
static unsigned _kernel_minor = 0;
static unsigned _kernel_release = 0;
static pthread_once_t _uname_once = PTHREAD_ONCE_INIT;

static void _init_uname(void)
{
  struct utsname uts;
  int parts;

  if (uname(&uts)) {
    log_sys_error("uname", "");
    _kernel_major = 0;
    return;
  }

  parts = sscanf(uts.release, "%u.%u.%u",
           &_kernel_major, &_kernel_minor, &_kernel_release);

  /* Kernels with a major number of 2 always had 3 parts. */
  if (parts < 1 || (_kernel_major < 3 && parts < 3)) {
    _kernel_major = 0;
    return;
  }
}

static int _uname(void)
{
  pthread_once(&_uname_once, _init_uname);

  if (!_kernel_major) {
    log_error("Could not determine kernel version used.");
    return 0;
  }

  return 1;
}

int get_uname_version(unsigned *major, unsigned *minor, unsigned *release)
{
  if (!_uname())
    return_0;

  *major = _kernel_major;
  *minor = _kernel_minor;
  *release = _kernel_release;

  return 1;
}

#ifdef DM_IOCTLS

/*
 * Set number to NULL to populate _dm_bitset - otherwise first
 * match is returned.
 * Returns:
 *  0 - error
 *  1 - success - number found
 *  2 - success - number not found (only if require_module_loaded=0)
 */
static int _get_proc_number(const char *file, const char *name,
          uint32_t *number, int require_module_loaded)
{
  FILE *fl;
  char nm[256];
  char *line = NULL;
  size_t len;
  uint32_t num;
  unsigned blocksection = (strcmp(file, PROC_DEVICES) == 0) ? 0 : 1;

  if (!(fl = fopen(file, "r"))) {
    log_sys_error("fopen", file);
    return 0;
  }

  while (getline(&line, &len, fl) != -1) {
    if (!blocksection && (line[0] == 'B'))
      blocksection = 1;
    else if (sscanf(line, "%u %255s\n", &num, &nm[0]) == 2) {
      if (!strcmp(name, nm)) {
        if (number) {
          *number = num;
          if (fclose(fl))
            log_sys_error("fclose", file);
          free(line);
          return 1;
        }
        dm_bit_set(_dm_bitset, num);
      }
    }
  }
  if (fclose(fl))
    log_sys_error("fclose", file);
  free(line);

  if (number) {
    if (require_module_loaded) {
      log_error("%s: No entry for %s found", file, name);
      return 0;
    }

    return 2;
  }

  return 1;
}

static int _control_device_number(uint32_t *major, uint32_t *minor)
{
  if (!_get_proc_number(PROC_DEVICES, MISC_NAME, major, 1) ||
      !_get_proc_number(PROC_MISC, DM_NAME, minor, 1)) {
    *major = 0;
    return 0;
  }

  return 1;
}

static int _control_unlink(const char *control)
{
  if (unlink(control) && (errno != ENOENT)) {
    log_sys_error("unlink", control);
    return -1;
  }

  return 0;
}

/*
 * Returns 1 if it exists on returning; 0 if it doesn't; -1 if it's wrong.
 */
static int _control_exists(const char *control, uint32_t major, uint32_t minor)
{
  struct stat buf;

  if (stat(control, &buf) < 0) {
    if (errno != ENOENT)
      log_sys_error("stat", control);
    return 0;
  }

  if (!S_ISCHR(buf.st_mode)) {
    log_verbose("%s: Wrong inode type", control);
    return _control_unlink(control);
  }

  if (major && buf.st_rdev != MKDEV(major, minor)) {
    log_verbose("%s: Wrong device number: (%u, %u) instead of "
          "(%u, %u).", control,
          MAJOR(buf.st_rdev), MINOR(buf.st_rdev),
          major, minor);
    return _control_unlink(control);
  }

  return 1;
}

static int _create_control(const char *control, uint32_t major, uint32_t minor)
{
  int ret;
  mode_t old_umask;

  /*
   * Return if the control already exists with intended major/minor
   * or there's an error unlinking an apparently incorrect one.
   */
  ret = _control_exists(control, major, minor);
  if (ret == -1)
    return_0; /* Failed to unlink existing incorrect node */
  if (ret)
    return 1; /* Already exists and correct */

  (void) dm_prepare_selinux_context(dm_dir(), S_IFDIR);
  old_umask = umask(DM_DEV_DIR_UMASK);
  ret = dm_create_dir(dm_dir());
  umask(old_umask);
  (void) dm_prepare_selinux_context(NULL, 0);

  if (!ret)
    return_0;

  log_verbose("Creating device %s (%u, %u)", control, major, minor);

  (void) dm_prepare_selinux_context(control, S_IFCHR);
  old_umask = umask(DM_CONTROL_NODE_UMASK);
  if (mknod(control, S_IFCHR | S_IRUSR | S_IWUSR,
      MKDEV(major, minor)) < 0)  {
    if (errno != EEXIST) {
      log_sys_error("mknod", control);
      ret = 0;
    } else if (_control_exists(control, major, minor) != 1) {
      stack; /* Invalid control node created by parallel command ? */
      ret = 0;
    }
  }
  umask(old_umask);
  (void) dm_prepare_selinux_context(NULL, 0);

  return ret;
}
#endif

/*
 * FIXME Update bitset in long-running process if dm claims new major numbers.
 */
/*
 * If require_module_loaded=0, caller is responsible to check
 * whether _dm_device_major or _dm_bitset is really set. If
 * it's not, it means the module is not loaded.
 */
static int _create_dm_bitset(int require_module_loaded)
{
  int r;

#ifdef DM_IOCTLS
  if (_dm_bitset || _dm_device_major)
    return 1;

  if (!_uname())
    return_0;

  /*
   * 2.6 kernels are limited to one major number.
   * Assume 2.4 kernels are patched not to.
   * FIXME Check _dm_version and _dm_version_minor if 2.6 changes this.
   */
  if (KERNEL_VERSION(_kernel_major, _kernel_minor, _kernel_release) >=
      KERNEL_VERSION(2, 6, 0))
    _dm_multiple_major_support = 0;

  if (!_dm_multiple_major_support) {
    if (!_get_proc_number(PROC_DEVICES, DM_NAME, &_dm_device_major,
              require_module_loaded))
      return 0;
    return 1;
  }

  /* Multiple major numbers supported */
  if (!(_dm_bitset = dm_bitset_create(NULL, NUMBER_OF_MAJORS)))
    return 0;

  r = _get_proc_number(PROC_DEVICES, DM_NAME, NULL, require_module_loaded);
  if (!r || r == 2) {
    dm_bitset_destroy(_dm_bitset);
    _dm_bitset = NULL;
    /*
     * It's not an error if we didn't find anything and we
     * didn't require module to be loaded at the same time.
     */
    return r == 2;
  }

  return 1;
#else
  return 0;
#endif
}

int dm_is_dm_major(uint32_t major)
{
  int r = 0;

  pthread_mutex_lock(&_control_fd_mutex);
  if (!_create_dm_bitset(0)) {
    pthread_mutex_unlock(&_control_fd_mutex);
    return 0;
  }

  if (_dm_multiple_major_support) {
    if (_dm_bitset)
      r = dm_bit(_dm_bitset, major) ? 1 : 0;
    pthread_mutex_unlock(&_control_fd_mutex);
    return r;
  }

  if (!_dm_device_major) {
    pthread_mutex_unlock(&_control_fd_mutex);
    return 0;
  }

  r = (major == _dm_device_major) ? 1 : 0;
  pthread_mutex_unlock(&_control_fd_mutex);

  return r;
}

static void _close_control_fd(void)
{
  if (_control_fd != -1) {
    if (close(_control_fd) < 0)
      log_sys_debug("close", "_control_fd");
    _control_fd = -1;
  }
}

#ifdef DM_IOCTLS
static int _open_and_assign_control_fd(const char *control)
{
  if ((_control_fd = open(control, O_RDWR)) < 0) {
    log_sys_error("open", control);
    return 0;
  }

  return 1;
}
#endif

static int _open_control(void)
{
#ifdef DM_IOCTLS
  char control[PATH_MAX];
  uint32_t major = MISC_MAJOR;
  uint32_t minor = MAPPER_CTRL_MINOR;

  if (_control_fd != -1)
    return 1;

  if (!_uname())
    return_0;

  if (dm_snprintf(control, sizeof(control), "%s/%s", dm_dir(), DM_CONTROL_NODE) < 0)
    goto_bad;

  /*
   * Prior to 2.6.36 the minor number should be looked up in /proc.
   */
  if ((KERNEL_VERSION(_kernel_major, _kernel_minor, _kernel_release) <
       KERNEL_VERSION(2, 6, 36)) &&
      !_control_device_number(&major, &minor))
    goto_bad;

  /*
   * Create the node with correct major and minor if not already done.
   * Udev may already have created /dev/mapper/control
   * from the modules.devname file generated by depmod.
   */
  if (!_create_control(control, major, minor))
    goto_bad;

  /*
   * As of 2.6.36 kernels, the open can trigger autoloading dm-mod.
   */
  if (!_open_and_assign_control_fd(control))
    goto_bad;

  if (!_create_dm_bitset(1)) {
    log_error("Failed to set up list of device-mapper major numbers");
    return 0;
  }

  return 1;

bad:
  log_error("Failure to communicate with kernel device-mapper driver.");
  if (!geteuid())
    log_error("Check that device-mapper is available in the kernel.");
  return 0;
#else
  return 1;
#endif
}

static int _get_control_fd(void)
{
  int fd;

  pthread_mutex_lock(&_control_fd_mutex);
  if (_control_fd == -1)
    _open_control();
  fd = _control_fd;
  pthread_mutex_unlock(&_control_fd_mutex);

  return fd;
}

static void _dm_zfree_string(char *string)
{
  if (string) {
    memset(string, 0, strlen(string));
    __asm__ volatile ("" ::: "memory"); /* Compiler barrier. */
    dm_free(string);
  }
}

static void _dm_zfree_dmi(struct dm_ioctl *dmi)
{
  if (dmi) {
    memset(dmi, 0, dmi->data_size);
    __asm__ volatile ("" ::: "memory"); /* Compiler barrier. */
    dm_free(dmi);
  }
}

static void _dm_task_free_targets(struct dm_task *dmt)
{
  struct target *t, *n;

  for (t = dmt->head; t; t = n) {
    n = t->next;
    if (dmt->secure_data)
      _dm_zfree_string(t->params);
    else
      dm_free(t->params);
    dm_free(t->type);
    dm_free(t);
  }

  dmt->head = dmt->tail = NULL;
}

void dm_task_destroy(struct dm_task *dmt)
{
  _dm_task_free_targets(dmt);
  if (dmt->secure_data)
    _dm_zfree_dmi(dmt->dmi.v4);
  else
    dm_free(dmt->dmi.v4);
  dm_free(dmt->dev_name);
  dm_free(dmt->mangled_dev_name);
  dm_free(dmt->newname);
  dm_free(dmt->message);
  dm_free(dmt->geometry);
  dm_free(dmt->uuid);
  dm_free(dmt->mangled_uuid);
  dm_timestamp_destroy(dmt->ioctl_timestamp);
  dm_free(dmt);
}

/*
 * Protocol Version 4 functions.
 */

int dm_task_get_driver_version(struct dm_task *dmt, char *version, size_t size)
{
  unsigned *v;

  if (!dmt->dmi.v4) {
    if (version)
      version[0] = '\0';
    return 0;
  }

  v = dmt->dmi.v4->version;
  if (version &&
      (snprintf(version, size, "%u.%u.%u", v[0], v[1], v[2]) < 0)) {
    log_error("Buffer for version is too short.");
    if (size > 0)
      version[0] = '\0';
    return 0;
  }

  return 1;
}

static int _check_version(char *version, size_t size)
{
  struct dm_task *task;
  int r;

  if (!(task = dm_task_create(DM_DEVICE_VERSION))) {
    log_error("Failed to get device-mapper version");
    version[0] = '\0';
    return 0;
  }

  r = dm_task_run(task);
  if (!dm_task_get_driver_version(task, version, size))
    stack;

  if (r && task->dmi.v4) {
    unsigned *v = task->dmi.v4->version;
    _dm_version = v[0];
    _dm_version_minor = v[1];
    _dm_version_patchlevel = v[2];
  }

  dm_task_destroy(task);

  return r;
}

static void _init_version(void)
{
  char libversion[64] = "", dmversion[64] = "";

  if (_check_version(dmversion, sizeof(dmversion)))
    return;

  dm_get_library_version(libversion, sizeof(libversion));

  log_error("Failed to communicate with device-mapper kernel driver (libdevmapper %s).",
      *libversion ? libversion : "(unknown version)");

  _version_ok = 0;
}

/*
 * Find out device-mapper's major version number the first time
 * this is called and whether or not we support it.
 */
int dm_check_version(void)
{
  pthread_once(&_version_once, _init_version);

  return _version_ok;
}

int dm_cookie_supported(void)
{
  return (dm_check_version() &&
    ((_dm_version == 4 && _dm_version_minor >= 15) || _dm_version > 4));
}

static int _dm_inactive_supported(void)
{
  int inactive_supported = 0;

  if (dm_check_version()) {
    if ((_dm_version == 4 && _dm_version_minor >= 16) || _dm_version > 4)
      inactive_supported = 1; /* upstream */
    else if (_dm_version == 4 && _dm_version_minor == 11 &&
       _dm_version_patchlevel >= 6 && _dm_version_patchlevel <= 40)
      inactive_supported = 1; /* RHEL 5.7 */
  }

  return inactive_supported;
}

int dm_message_supports_precise_timestamps(void)
{
  /*
   * 4.32.0 supports "precise_timestamps" and "histogram:" options
   * to @stats_create messages but lacks the ability to report
   * these properties via a subsequent @stats_list: require at
   * least 4.33.0 in order to use these features.
   */
  if (dm_check_version() &&
      ((_dm_version == 4 && _dm_version_minor >= 33) || _dm_version > 4))
    return 1;
  return 0;
}

void *dm_get_next_target(struct dm_task *dmt, void *next,
       uint64_t *start, uint64_t *length,
       char **target_type, char **params)
{
  struct target *t = (struct target *) next;

  if (!t)
    t = dmt->head;

  if (!t) {
    *start = 0;
    *length = 0;
    *target_type = 0;
    *params = 0;
    return NULL;
  }

  *start = t->start;
  *length = t->length;
  *target_type = t->type;
  *params = t->params;

  return t->next;
}

/* Unmarshal the target info returned from a status call */
static int _unmarshal_status(struct dm_task *dmt, struct dm_ioctl *dmi)
{
  char *outbuf = (char *) dmi + dmi->data_start;
  char *outptr = outbuf;
  uint32_t i;
  struct dm_target_spec *spec;

  _dm_task_free_targets(dmt);

  for (i = 0; i < dmi->target_count; i++) {
    spec = (struct dm_target_spec *) outptr;
    if (!dm_task_add_target(dmt, spec->sector_start,
          spec->length,
          spec->target_type,
          outptr + sizeof(*spec))) {
      return 0;
    }

    outptr = outbuf + spec->next;
  }

  return 1;
}

int dm_format_dev(char *buf, int bufsize, uint32_t dev_major,
      uint32_t dev_minor)
{
  int r;

  if (bufsize < 8)
    return 0;

  r = snprintf(buf, (size_t) bufsize, "%u:%u", dev_major, dev_minor);
  if (r < 0 || r > bufsize - 1)
    return 0;

  return 1;
}

DM_EXPORT_NEW_SYMBOL(int, dm_task_get_info, 1_02_97)
  (struct dm_task *dmt, struct dm_info *info)
{
  if (!dmt->dmi.v4)
    return 0;

  memset(info, 0, sizeof(*info));

  info->exists = dmt->dmi.v4->flags & DM_EXISTS_FLAG ? 1 : 0;
  if (!info->exists)
    return 1;

  info->suspended = dmt->dmi.v4->flags & DM_SUSPEND_FLAG ? 1 : 0;
  info->read_only = dmt->dmi.v4->flags & DM_READONLY_FLAG ? 1 : 0;
  info->live_table = dmt->dmi.v4->flags & DM_ACTIVE_PRESENT_FLAG ? 1 : 0;
  info->inactive_table = dmt->dmi.v4->flags & DM_INACTIVE_PRESENT_FLAG ?
      1 : 0;
  info->deferred_remove = dmt->dmi.v4->flags & DM_DEFERRED_REMOVE_FLAG ? 1 : 0;
  info->internal_suspend = (dmt->dmi.v4->flags & DM_INTERNAL_SUSPEND_FLAG) ? 1 : 0;
  info->target_count = dmt->dmi.v4->target_count;
  info->open_count = dmt->dmi.v4->open_count;
  info->event_nr = dmt->dmi.v4->event_nr;
  info->major = MAJOR(dmt->dmi.v4->dev);
  info->minor = MINOR(dmt->dmi.v4->dev);

  return 1;
}

uint32_t dm_task_get_read_ahead(const struct dm_task *dmt, uint32_t *read_ahead)
{
  const char *dev_name;

  *read_ahead = 0;

  if (!dmt->dmi.v4 || !(dmt->dmi.v4->flags & DM_EXISTS_FLAG))
    return 0;

  if (*dmt->dmi.v4->name)
    dev_name = dmt->dmi.v4->name;
  else if (!(dev_name = DEV_NAME(dmt))) {
    log_error("Get read ahead request failed: device name unrecorded.");
    return 0;
  }

  return get_dev_node_read_ahead(dev_name, MAJOR(dmt->dmi.v4->dev),
               MINOR(dmt->dmi.v4->dev), read_ahead);
}

struct dm_deps *dm_task_get_deps(struct dm_task *dmt)
{
  if (!dmt) {
    log_error(INTERNAL_ERROR "Missing dm_task.");
    return NULL;
  }

  return (struct dm_deps *) (((char *) dmt->dmi.v4) +
           dmt->dmi.v4->data_start);
}

/*
 * Round up the ptr to an 8-byte boundary.
 * Follow kernel pattern.
 */
#define ALIGN_MASK 7
static size_t _align_val(size_t val)
{
  return (val + ALIGN_MASK) & ~ALIGN_MASK;
}
static void *_align_ptr(void *ptr)
{
  return (void *)(uintptr_t)_align_val((size_t)ptr);
}

static int _has_event_nr = 0;
static pthread_once_t _has_event_nr_once = PTHREAD_ONCE_INIT;

static void _init_has_event_nr(void)
{
  _has_event_nr = dm_check_version() &&
    ((_dm_version == 4 && _dm_version_minor >= 38) || _dm_version > 4);
}

static int _check_has_event_nr(void) {
  pthread_once(&_has_event_nr_once, _init_has_event_nr);

  return _has_event_nr;
}

struct dm_names *dm_task_get_names(struct dm_task *dmt)
{
  return (struct dm_names *) (((char *) dmt->dmi.v4) +
            dmt->dmi.v4->data_start);
}

struct dm_versions *dm_task_get_versions(struct dm_task *dmt)
{
  return (struct dm_versions *) (((char *) dmt->dmi.v4) +
               dmt->dmi.v4->data_start);
}

int dm_task_get_device_list(struct dm_task *dmt, struct dm_list **devs_list,
          unsigned *devs_features)
{
  struct dm_names *names, *names1 = NULL;
  struct dm_active_device *dm_dev, *dm_new_dev;
  struct dm_list *devs;
  unsigned next = 0;
  uint32_t *event_nr;
  char *uuid_ptr;
  size_t len;
  int cnt = 0;

  *devs_list = 0;
  *devs_features = 0;

  if ((names = dm_task_get_names(dmt)) && names->dev) {
    names1 = names;
    if (!names->name[0])
      cnt = -1; /* -> cnt == 0 when no device is really present */
    do {
      names1 = (struct dm_names *)((char *) names1 + next);
      next = names1->next;
      ++cnt;
    } while (next);
  }

  /* buffer for devs +  sorted ptrs + dm_devs + aligned strings */
  if (!(devs = malloc(sizeof(*devs) + cnt * (2 * sizeof(void*) + sizeof(*dm_dev)) +
          (cnt ? (char*)names1 - (char*)names + 256 : 0))))
    return_0;

  dm_list_init(devs);

  if (!cnt) {
    /* nothing in the list -> mark all features present */
    *devs_features |= (DM_DEVICE_LIST_HAS_EVENT_NR | DM_DEVICE_LIST_HAS_UUID);
    goto out; /* nothing else to do */
  }

  /* Shift position where to store individual dm_devs */
  dm_dev = (struct dm_active_device *) ((long*) (devs + 1) + cnt);

  do {
    names = (struct dm_names *)((char *) names + next);

    dm_dev->devno = (dev_t) names->dev;
    dm_dev->name = (const char *)(dm_dev + 1);
    dm_dev->event_nr = 0;
    dm_dev->uuid = "";

    len = strlen(names->name) + 1;
    memcpy((char*)dm_dev->name, names->name, len);

    dm_new_dev = _align_ptr((char*)(dm_dev + 1) + len);
    if (_check_has_event_nr()) {

      *devs_features |= DM_DEVICE_LIST_HAS_EVENT_NR;
      event_nr = _align_ptr(names->name + len);
      dm_dev->event_nr = event_nr[0];

      if ((event_nr[1] & DM_NAME_LIST_FLAG_HAS_UUID)) {
        *devs_features |= DM_DEVICE_LIST_HAS_UUID;
        uuid_ptr = _align_ptr(event_nr + 2);
        len = strlen(uuid_ptr) + 1;
        memcpy(dm_new_dev, uuid_ptr, len);
        dm_dev->uuid = (const char *) dm_new_dev;
        dm_new_dev = _align_ptr((char*)dm_new_dev + len);
      }
    }

    dm_list_add(devs, &dm_dev->list);
    dm_dev = dm_new_dev;
    next = names->next;
  } while (next);

    out:
  *devs_list = devs;

  return 1;
}

void dm_device_list_destroy(struct dm_list **devs_list)
{
  struct dm_device_list *devs = (struct dm_device_list *) *devs_list;

  if (devs) {
    free(devs);
    *devs_list = NULL;
  }
}

int dm_device_list_equal(const struct dm_list *list1, const struct dm_list *list2)
{
  const struct dm_active_device *dev1, *dev2;
  const struct dm_list *l2;

  if (!list1 || !list2)
    return (list1 == list2);

  if (!(l2 = dm_list_first(list2)))
    return dm_list_empty(list1);

  dm_list_iterate_items(dev1, list1) {
    dev2 = dm_list_item(l2, struct dm_active_device);
    if ((dev1->devno != dev2->devno) || strcmp(dev1->uuid, dev2->uuid))
      return 0;
    if (!(l2 = dm_list_next(list2, l2)))
      return !dm_list_next(list1, &dev1->list);
  }

  return 1;
}

const char *dm_task_get_message_response(struct dm_task *dmt)
{
  const char *start, *end;

  if (!(dmt->dmi.v4->flags & DM_DATA_OUT_FLAG))
    return NULL;

  start = (const char *) dmt->dmi.v4 + dmt->dmi.v4->data_start;
  end = (const char *) dmt->dmi.v4 + dmt->dmi.v4->data_size;

  if (end < start) {
    log_error(INTERNAL_ERROR "Corrupted message structure returned: start %d > end %d", (int)dmt->dmi.v4->data_start, (int)dmt->dmi.v4->data_size);
    return NULL;
  }

  if (!memchr(start, 0, end - start)) {
    log_error(INTERNAL_ERROR "Message response doesn't contain terminating NUL character");
    return NULL;
  }

  return start;
}

int dm_task_set_ro(struct dm_task *dmt)
{
  dmt->read_only = 1;
  return 1;
}

int dm_task_set_read_ahead(struct dm_task *dmt, uint32_t read_ahead,
         uint32_t read_ahead_flags)
{
  dmt->read_ahead = read_ahead;
  dmt->read_ahead_flags = read_ahead_flags;

  return 1;
}

int dm_task_suppress_identical_reload(struct dm_task *dmt)
{
  dmt->suppress_identical_reload = 1;
  return 1;
}

int dm_task_set_add_node(struct dm_task *dmt, dm_add_node_t add_node)
{
  switch (add_node) {
  case DM_ADD_NODE_ON_RESUME:
  case DM_ADD_NODE_ON_CREATE:
    dmt->add_node = add_node;
    return 1;
  default:
    log_error("Unknown add node parameter");
    return 0;
  }
}

int dm_task_set_newuuid(struct dm_task *dmt, const char *newuuid)
{
  dm_string_mangling_t mangling_mode = dm_get_name_mangling_mode();
  char mangled_uuid[DM_UUID_LEN];
  int r = 0;

  if (strlen(newuuid) >= DM_UUID_LEN) {
    log_error("Uuid \"%s\" too long", newuuid);
    return 0;
  }

  if (!check_multiple_mangled_string_allowed(newuuid, "new UUID", mangling_mode))
    return_0;

  if (mangling_mode != DM_STRING_MANGLING_NONE &&
      (r = mangle_string(newuuid, "new UUID", strlen(newuuid), mangled_uuid,
             sizeof(mangled_uuid), mangling_mode)) < 0) {
    log_error("Failed to mangle new device UUID \"%s\"", newuuid);
    return 0;
  }

  if (r) {
    log_debug_activation("New device uuid mangled [%s]: %s --> %s",
             mangling_mode == DM_STRING_MANGLING_AUTO ? "auto" : "hex",
             newuuid, mangled_uuid);
    newuuid = mangled_uuid;
  }

  dm_free(dmt->newname);
  if (!(dmt->newname = dm_strdup(newuuid))) {
    log_error("dm_task_set_newuuid: strdup(%s) failed", newuuid);
    return 0;
  }
  dmt->new_uuid = 1;

  return 1;
}

int dm_task_set_message(struct dm_task *dmt, const char *message)
{
  dm_free(dmt->message);
  if (!(dmt->message = dm_strdup(message))) {
    log_error("dm_task_set_message: strdup failed");
    return 0;
  }

  return 1;
}

int dm_task_set_sector(struct dm_task *dmt, uint64_t sector)
{
  dmt->sector = sector;

  return 1;
}

int dm_task_set_geometry(struct dm_task *dmt, const char *cylinders, const char *heads,
       const char *sectors, const char *start)
{
  dm_free(dmt->geometry);
  if (dm_asprintf(&(dmt->geometry), "%s %s %s %s",
      cylinders, heads, sectors, start) < 0) {
    log_error("dm_task_set_geometry: sprintf failed");
    return 0;
  }

  return 1;
}

int dm_task_no_flush(struct dm_task *dmt)
{
  dmt->no_flush = 1;

  return 1;
}

int dm_task_no_open_count(struct dm_task *dmt)
{
  dmt->no_open_count = 1;

  return 1;
}

int dm_task_skip_lockfs(struct dm_task *dmt)
{
  dmt->skip_lockfs = 1;

  return 1;
}

int dm_task_secure_data(struct dm_task *dmt)
{
  dmt->secure_data = 1;

  return 1;
}

int dm_task_ima_measurement(struct dm_task *dmt)
{
  dmt->ima_measurement = 1;

  return 1;
}

int dm_task_retry_remove(struct dm_task *dmt)
{
  dmt->retry_remove = 1;

  return 1;
}

int dm_task_deferred_remove(struct dm_task *dmt)
{
  dmt->deferred_remove = 1;

  return 1;
}

int dm_task_query_inactive_table(struct dm_task *dmt)
{
  dmt->query_inactive_table = 1;

  return 1;
}

int dm_task_set_event_nr(struct dm_task *dmt, uint32_t event_nr)
{
  dmt->event_nr = event_nr;

  return 1;
}

int dm_task_set_record_timestamp(struct dm_task *dmt)
{
  if (!dmt->ioctl_timestamp)
    dmt->ioctl_timestamp = dm_timestamp_alloc();

  if (!dmt->ioctl_timestamp)
    return_0;

  dmt->record_timestamp = 1;

  return 1;
}

struct dm_timestamp *dm_task_get_ioctl_timestamp(struct dm_task *dmt)
{
  return dmt->record_timestamp ? dmt->ioctl_timestamp : NULL;
}

struct target *create_target(uint64_t start, uint64_t len, const char *type,
           const char *params)
{
  struct target *t;

  if (strlen(type) >= DM_MAX_TYPE_NAME) {
    log_error("Target type name %s is too long.", type);
    return NULL;
  }

  if (!(t = dm_zalloc(sizeof(*t)))) {
    log_error("create_target: malloc(%" PRIsize_t ") failed",
        sizeof(*t));
    return NULL;
  }

  if (!(t->params = dm_strdup(params))) {
    log_error("create_target: strdup(params) failed");
    goto bad;
  }

  if (!(t->type = dm_strdup(type))) {
    log_error("create_target: strdup(type) failed");
    goto bad;
  }

  t->start = start;
  t->length = len;
  return t;

      bad:
  _dm_zfree_string(t->params);
  dm_free(t->type);
  dm_free(t);
  return NULL;
}

static char *_add_target(struct target *t, char *out, char *end)
{
  char *out_sp = out;
  struct dm_target_spec sp;
  size_t sp_size = sizeof(struct dm_target_spec);
  unsigned int backslash_count = 0;
  int len;
  char *pt;

  if (strlen(t->type) >= sizeof(sp.target_type)) {
    log_error("Target type name %s is too long.", t->type);
    return NULL;
  }

  sp.status = 0;
  sp.sector_start = t->start;
  sp.length = t->length;
  strncpy(sp.target_type, t->type, sizeof(sp.target_type) - 1);
  sp.target_type[sizeof(sp.target_type) - 1] = '\0';

  out += sp_size;
  pt = t->params;

  while (*pt)
    if (*pt++ == '\\')
      backslash_count++;

  len = strlen(t->params) + 1;

  if ((out >= end) || (out + len + backslash_count) >= end) {
    log_error("Ran out of memory building ioctl parameter");
    return NULL;
  }

  if (backslash_count) {
    /* replace "\" with "\\" */
    pt = t->params;
    do {
      if (*pt == '\\')
        *out++ = '\\';
      *out++ = *pt++;
    } while (*pt);
    *out++ = '\0';
  }
  else {
    memcpy(out, t->params, len);
    out += len;
  }

  /* align next block */
  out = _align(out, ALIGNMENT);

  sp.next = out - out_sp;
  memcpy(out_sp, &sp, sp_size);

  return out;
}

static int _lookup_dev_name(uint64_t dev, char *buf, size_t len)
{
  struct dm_names *names;
  unsigned next = 0;
  struct dm_task *dmt;
  int r = 0;

  if (!(dmt = dm_task_create(DM_DEVICE_LIST)))
    return 0;

  if (!dm_task_run(dmt))
    goto out;

  if (!(names = dm_task_get_names(dmt)))
    goto out;

  if (!names->dev)
    goto out;

  do {
    names = (struct dm_names *)((char *) names + next);
    if (names->dev == dev) {
      memccpy(buf, names->name, 0, len);
      r = 1;
      break;
    }
    next = names->next;
  } while (next);

      out:
  dm_task_destroy(dmt);
  return r;
}

static int _add_params(int type)
{
  switch (type) {
  case DM_DEVICE_REMOVE_ALL:
  case DM_DEVICE_CREATE:
  case DM_DEVICE_REMOVE:
  case DM_DEVICE_SUSPEND:
  case DM_DEVICE_STATUS:
  case DM_DEVICE_CLEAR:
  case DM_DEVICE_ARM_POLL:
    return 0; /* IOCTL_FLAGS_NO_PARAMS in drivers/md/dm-ioctl.c */
  default:
    return 1;
  }
}

static struct dm_ioctl *_flatten(struct dm_task *dmt, unsigned repeat_count)
{
  size_t min_size;
  const int (*version)[3];

  struct dm_ioctl *dmi;
  struct target *t;
  struct dm_target_msg *tmsg;
  size_t len = sizeof(struct dm_ioctl);
  size_t message_len = 0, newname_len = 0, geometry_len = 0;
  char *b, *e;
  int count = 0;

  if (_add_params(dmt->type))
    for (t = dmt->head; t; t = t->next) {
      len += sizeof(struct dm_target_spec);
      len += strlen(t->params) + 1 + ALIGNMENT;
      count++;
    }
  else if (dmt->head)
    log_debug_activation(INTERNAL_ERROR "dm '%s' ioctl should not define parameters.",
             _cmd_data_v4[dmt->type].name);
  switch (dmt->type) {
  case DM_DEVICE_CREATE:
  case DM_DEVICE_DEPS:
  case DM_DEVICE_LIST:
  case DM_DEVICE_STATUS:
  case DM_DEVICE_TABLE:
  case DM_DEVICE_TARGET_MSG:
    min_size = 16 * 1024;
    break;
  default:
    min_size = 2 * 1024;
  }

  if (count && (dmt->sector || dmt->message)) {
    log_error("targets and message are incompatible");
    return NULL;
  }

  if (count && dmt->newname) {
    log_error("targets and rename are incompatible");
    return NULL;
  }

  if (count && dmt->geometry) {
    log_error("targets and geometry are incompatible");
    return NULL;
  }

  if (dmt->newname && (dmt->sector || dmt->message)) {
    log_error("message and rename are incompatible");
    return NULL;
  }

  if (dmt->newname && dmt->geometry) {
    log_error("geometry and rename are incompatible");
    return NULL;
  }

  if (dmt->geometry && (dmt->sector || dmt->message)) {
    log_error("geometry and message are incompatible");
    return NULL;
  }

  if (dmt->sector && !dmt->message) {
    log_error("message is required with sector");
    return NULL;
  }

  if (dmt->newname) {
    newname_len = strlen(dmt->newname) + 1;
    len += newname_len;
  }

  if (dmt->message) {
    message_len = strlen(dmt->message) + 1;
    len += sizeof(struct dm_target_msg) + message_len;
  }

  if (dmt->geometry) {
    geometry_len = strlen(dmt->geometry) + 1;
    len += geometry_len;
  }

  /*
   * Give len a minimum size so that we have space to store
   * dependencies or status information.
   */
  if (len < min_size)
    len = min_size;

  /* Increase buffer size if repeating because buffer was too small */
  while (repeat_count--)
    len *= 2;

  if (!(dmi = dm_zalloc(len)))
    return NULL;

  version = &_cmd_data_v4[dmt->type].version;

  dmi->version[0] = (*version)[0];
  dmi->version[1] = (*version)[1];
  dmi->version[2] = (*version)[2];

  dmi->data_size = len;
  dmi->data_start = sizeof(struct dm_ioctl);

  if (dmt->minor >= 0) {
    if (!_dm_multiple_major_support && dmt->allow_default_major_fallback &&
        dmt->major != (int) _dm_device_major) {
      log_verbose("Overriding major number of %d "
            "with %u for persistent device.",
            dmt->major, _dm_device_major);
      dmt->major = _dm_device_major;
    }

    if (dmt->major <= 0) {
      log_error("Missing major number for persistent device.");
      goto bad;
    }

    dmi->flags |= DM_PERSISTENT_DEV_FLAG;
    dmi->dev = MKDEV(dmt->major, dmt->minor);
  }

  /* Does driver support device number referencing? */
  if (_dm_version_minor < 3 && !DEV_NAME(dmt) && !DEV_UUID(dmt) && dmi->dev) {
    if (!_lookup_dev_name(dmi->dev, dmi->name, sizeof(dmi->name))) {
      log_error("Unable to find name for device (%d:%d).",
          dmt->major, dmt->minor);
      goto bad;
    }
    log_verbose("device (%d:%d) is %s "
          "for compatibility with old kernel.",
          dmt->major, dmt->minor, dmi->name);
  }

  /* FIXME Until resume ioctl supplies name, use dev_name for readahead */
  if (DEV_NAME(dmt) &&
      (((dmt->type != DM_DEVICE_RESUME) &&
        (dmt->type != DM_DEVICE_RELOAD) &&
        (dmt->type != DM_DEVICE_REMOVE)) ||
       (dmt->minor < 0) || (dmt->major < 0)))
    /* When RESUME, RELOAD or REMOVE sets maj:min and dev_name,
     * use just maj:min for the ioctl; dev_name stays on dmt
     * for error/debug messages and _dm_task_node_ops */
    memccpy(dmi->name, DEV_NAME(dmt), 0, sizeof(dmi->name));

  if (DEV_UUID(dmt))
    memccpy(dmi->uuid, DEV_UUID(dmt), 0, sizeof(dmi->uuid));

  if (dmt->type == DM_DEVICE_SUSPEND)
    dmi->flags |= DM_SUSPEND_FLAG;
  if (dmt->no_flush) {
    if (_dm_version_minor < 12)
      log_verbose("No flush flag unsupported by kernel. "
            "Buffers will be flushed.");
    else
      dmi->flags |= DM_NOFLUSH_FLAG;
  }
  if (dmt->read_only)
    dmi->flags |= DM_READONLY_FLAG;
  if (dmt->skip_lockfs)
    dmi->flags |= DM_SKIP_LOCKFS_FLAG;
  if (dmt->deferred_remove && (dmt->type == DM_DEVICE_REMOVE || dmt->type == DM_DEVICE_REMOVE_ALL))
    dmi->flags |= DM_DEFERRED_REMOVE_FLAG;

  if (dmt->secure_data) {
    if (_dm_version_minor < 20)
      log_verbose("Secure data flag unsupported by kernel. "
            "Buffers will not be wiped after use.");
    dmi->flags |= DM_SECURE_DATA_FLAG;
  }
  if (dmt->query_inactive_table) {
    if (!_dm_inactive_supported())
      log_warn_suppress(_dm_warn_inactive_suppress++,
            "WARNING: Inactive table query unsupported by kernel. "
            "It will use live table.");
    dmi->flags |= DM_QUERY_INACTIVE_TABLE_FLAG;
  }
  if (dmt->new_uuid) {
    if (_dm_version_minor < 19) {
      log_error("Setting UUID unsupported by kernel. "
          "Aborting operation.");
      goto bad;
    }
    dmi->flags |= DM_UUID_FLAG;
  }
  if (dmt->ima_measurement) {
    if (_dm_version_minor < 45) {
      log_error("IMA measurement unsupported by kernel. "
          "Aborting operation.");
      goto bad;
    }
    dmi->flags |= DM_IMA_MEASUREMENT_FLAG;
  }

  dmi->target_count = count;
  dmi->event_nr = dmt->event_nr;

  b = (char *) (dmi + 1);
  e = (char *) dmi + len;

  if (_add_params(dmt->type))
    for (t = dmt->head; t; t = t->next)
      if (!(b = _add_target(t, b, e)))
        goto_bad;

  if (dmt->newname)
    memcpy(b, dmt->newname, newname_len);

  if (dmt->message) {
    tmsg = (struct dm_target_msg *) b;
    tmsg->sector = dmt->sector;
    memcpy(tmsg->message, dmt->message, message_len);
  }

  if (dmt->geometry)
    memcpy(b, dmt->geometry, geometry_len);

  return dmi;

      bad:
  _dm_zfree_dmi(dmi);
  return NULL;
}

static int _process_mapper_dir(struct dm_task *dmt)
{
  struct dirent *dirent;
  DIR *d;
  const char *dir;
  int r = 1;

  dir = dm_dir();
  if (!(d = opendir(dir))) {
    log_sys_error("opendir", dir);
    return 0;
  }

  while ((dirent = readdir(d))) {
    if (!strcmp(dirent->d_name, ".") ||
        !strcmp(dirent->d_name, "..") ||
        !strcmp(dirent->d_name, "control"))
      continue;
    if (!dm_task_set_name(dmt, dirent->d_name)) {
      r = 0;
      stack;
      continue; /* try next name */
    }
    if (!dm_task_run(dmt)) {
      r = 0;
      stack;  /* keep going */
    }
  }

  if (closedir(d))
    log_sys_debug("closedir", dir);

  return r;
}

static int _process_all_v4(struct dm_task *dmt)
{
  struct dm_task *task;
  struct dm_names *names;
  unsigned next = 0;
  int r = 1;

  if (!(task = dm_task_create(DM_DEVICE_LIST)))
    return 0;

  if (!dm_task_run(task)) {
    r = 0;
    goto out;
  }

  if (!(names = dm_task_get_names(task))) {
    r = 0;
    goto out;
  }

  if (!names->dev)
    goto out;

  do {
    names = (struct dm_names *)((char *) names + next);
    if (!dm_task_set_name(dmt, names->name)) {
      r = 0;
      goto out;
    }
    if (!dm_task_run(dmt))
      r = 0;
    next = names->next;
  } while (next);

      out:
  dm_task_destroy(task);
  return r;
}

static int _mknodes_v4(struct dm_task *dmt)
{
  (void) _process_mapper_dir(dmt);

  return _process_all_v4(dmt);
}

/*
 * If an operation that uses a cookie fails, decrement the
 * semaphore instead of udev.
 */
static int _udev_complete(struct dm_task *dmt)
{
  uint16_t base;

  if (dmt->cookie_set &&
      (base = dmt->event_nr & ~DM_UDEV_FLAGS_MASK))
    /* strip flags from the cookie and use cookie magic instead */
    return dm_udev_complete(base | (DM_COOKIE_MAGIC <<
            DM_UDEV_FLAGS_SHIFT));

  return 1;
}

#ifdef DM_IOCTLS
static int _check_uevent_generated(struct dm_ioctl *dmi)
{
  if (!dm_check_version() ||
      ((_dm_version == 4 && _dm_version_minor < 17) || _dm_version < 4))
    /* can't check, assume uevent is generated */
    return 1;

  return dmi->flags & DM_UEVENT_GENERATED_FLAG;
}
#endif

/*
 * Create a RELOAD task and populate it with table data.
 * Used by both _create_and_load_v4() and the async create chain.
 * The target list (head/tail) is moved -- caller must NULL its own copy.
 * Returns the new task on success, NULL on failure.
 */
static struct dm_task *_new_reload_task(const char *name,
          struct target *head,
          struct target *tail,
          int read_only,
          int secure_data,
          int ima_measurement,
          int major,
          int minor)
{
  struct dm_task *task;

  if (!(task = dm_task_create(DM_DEVICE_RELOAD)))
    return_NULL;

  if (name && !dm_task_set_name(task, name)) {
    dm_task_destroy(task);
    return_NULL;
  }

  task->read_only = read_only;
  task->head = head;
  task->tail = tail;
  task->secure_data = secure_data;
  task->ima_measurement = ima_measurement;
  task->major = major;
  task->minor = minor;

  return task;
}

/*
 * Revert a failed CREATE-with-table by issuing a synchronous REMOVE.
 * If cookie_set, sets up a udev cookie for the remove.
 * Used by both _create_and_load_v4() and the async create chain.
 */
static void _revert_create(const char *dev_name,
         int cookie_set, uint32_t event_nr)
{
  struct dm_task *dmt;
  uint32_t cookie;

  if (!dev_name || !*dev_name)
    return;

  if (!(dmt = dm_task_create(DM_DEVICE_REMOVE)))
    return;

  if (!dm_task_set_name(dmt, dev_name)) {
    dm_task_destroy(dmt);
    return;
  }

  if (cookie_set) {
    cookie = (event_nr & ~DM_UDEV_FLAGS_MASK) |
       (DM_COOKIE_MAGIC << DM_UDEV_FLAGS_SHIFT);
    if (!dm_task_set_cookie(dmt, &cookie,
          (event_nr & DM_UDEV_FLAGS_MASK) >>
          DM_UDEV_FLAGS_SHIFT))
      stack; /* keep going */
  }

  if (!dm_task_run(dmt))
    log_error("Failed to revert device creation.");

  dm_task_destroy(dmt);
}

static int _create_and_load_v4(struct dm_task *dmt)
{
  struct dm_info info;
  struct dm_task *task;
  int r, ioctl_errno = 0;

  /* Use new task struct to create the device */
  if (!(task = dm_task_create(DM_DEVICE_CREATE))) {
    _udev_complete(dmt);
    return_0;
  }

  /* Copy across relevant fields */
  if (dmt->dev_name && !dm_task_set_name(task, dmt->dev_name))
    goto_bad;

  if (dmt->uuid && !dm_task_set_uuid(task, dmt->uuid))
    goto_bad;

  task->major = dmt->major;
  task->minor = dmt->minor;
  task->uid = dmt->uid;
  task->gid = dmt->gid;
  task->mode = dmt->mode;
  /* FIXME: Just for udev_check in dm_task_run. Can we avoid this? */
  task->event_nr = dmt->event_nr & DM_UDEV_FLAGS_MASK;
  task->cookie_set = dmt->cookie_set;
  task->add_node = dmt->add_node;

  if (!dm_task_run(task)) {
    ioctl_errno = task->ioctl_errno;
    goto_bad;
  }

  if (!dm_task_get_info(task, &info) || !info.exists)
    goto_bad;

  dm_task_destroy(task);

  /* Next load the table */
  if (!(task = _new_reload_task(dmt->dev_name, dmt->head, dmt->tail,
              dmt->read_only, dmt->secure_data,
              dmt->ima_measurement,
              info.major, info.minor))) {
    stack;
    _udev_complete(dmt);
    goto revert;
  }

  r = dm_task_run(task);
  if (!r)
    ioctl_errno = task->ioctl_errno;

  task->head = NULL;
  task->tail = NULL;
  dm_task_destroy(task);

  if (!r) {
    stack;
    _udev_complete(dmt);
    goto revert;
  }

  /* Use the original structure last so the info will be correct */
  dmt->type = DM_DEVICE_RESUME;
  dm_free(dmt->uuid);
  dmt->uuid = NULL;
  dm_free(dmt->mangled_uuid);
  dmt->mangled_uuid = NULL;
  /* coverity[double_free] recursive function call */
  _dm_task_free_targets(dmt);

  if (dm_task_run(dmt))
    return 1;

      revert:
  _revert_create(dmt->dev_name, dmt->cookie_set, dmt->event_nr);

  if (ioctl_errno != 0)
    dmt->ioctl_errno =  ioctl_errno;

  return 0;

      bad:
  dm_task_destroy(task);
  _udev_complete(dmt);

  if (ioctl_errno != 0)
    dmt->ioctl_errno =  ioctl_errno;

  return 0;
}

uint64_t dm_task_get_existing_table_size(const struct dm_task *dmt)
{
  return dmt->existing_table_size;
}

/*
 * Skip "rebuild N" or "write_mostly N" token pair.
 * Old dm-raid may drop these from table output.
 */
static int _skip_raid_volatile_token(const char **pp)
{
  const char *p = *pp;

  if (strncmp(p, "rebuild ", 8) &&
      strncmp(p, "write_mostly ", 13))
    return 0;

  while (*p && *p != ' ')
    p++;
  if (*p == ' ')
    p++;
  while (*p && *p != ' ')
    p++;
  if (*p == ' ')
    p++;

  *pp = p;
  return 1;
}

/*
 * Check if raid params are functionally equivalent.
 * p1 = new table, p2 = active table (kernel STATUSTYPE_TABLE).
 *
 * Old dm-raid (< 1.15.1) double-counts rebuild/writemostly in
 * the param count, and early versions drop "rebuild N" from
 * table output once In_sync is set.  Both cause spurious string
 * mismatches that defeat reload suppression.  We skip the param
 * count and ignore volatile "rebuild N" / "write_mostly N" pairs.
 *
 * The 'suspended' flag gates which side gets the volatile skip.
 * Do not simplify this to always-symmetric or always-asymmetric.
 * When NOT suspended, skip only in p2 -- a rebuild in p1 is a
 * deliberate request that must trigger a reload.  When suspended,
 * skip in both p1 and p2 -- LVM is in the second preload pass
 * (the first already loaded the rebuild table via force_reload),
 * the active table is stale, and a redundant reload here would
 * hit "Internal error: table load while devices are suspended".
 */
static int _raid_params_equiv(const char *p1, const char *p2,
            int suspended)
{
  const char *s1 = strchr(p1, ' ');
  const char *s2 = strchr(p2, ' ');

  if (!s1 || !s2)
    return 0;

  /* Raid personality must match */
  if ((s1 - p1) != (s2 - p2) ||
      memcmp(p1, p2, s1 - p1))
    return 0;

  /* Skip past the param count */
  s1 = strchr(s1 + 1, ' ');
  s2 = strchr(s2 + 1, ' ');

  if (!s1 || !s2)
    return 0;

  /* Fast path */
  if (!strcmp(s1, s2))
    return 1;

  s1++;
  s2++;

  for (;;) {
    if (suspended)
      while (*s1 && _skip_raid_volatile_token(&s1))
        ;
    while (*s2 && _skip_raid_volatile_token(&s2))
      ;

    if (!*s1 && !*s2)
      return 1;

    if (!*s1 || !*s2)
      return 0;

    while (*s1 && *s2 && *s1 != ' ' && *s2 != ' ') {
      if (*s1 != *s2)
        return 0;
      s1++;
      s2++;
    }

    if ((*s1 && *s1 != ' ') || (*s2 && *s2 != ' '))
      return 0;

    if (*s1 == ' ')
      s1++;
    if (*s2 == ' ')
      s2++;
  }
}

/*
 * Check if integrity params are functionally equivalent.
 * p1 = new table params, p2 = active table params (kernel STATUSTYPE_TABLE).
 *
 * Kernel's integrity table output differs from what LVM emits:
 *
 * - block_size:512 -- LVM always emits, kernel omits when
 *   sectors_per_block==1 (the default).
 *
 * - fix_padding -- LVM always emits, kernel only reports when
 *   SB_FLAG_FIXED_PADDING is set in the on-disk superblock
 *   (written once by initialize_superblock(), NOT on reload).
 *
 * - recalculate -- kernel reports from SB_FLAG_RECALCULATING in the
 *   on-disk superblock, not from the constructor table line.
 *   The kernel NEVER clears this flag; recalc_sector simply advances
 *   past provided_data_sectors.  LVM clears integrity_recalculate in
 *   VG metadata after the first activation (integrity_manip.c), so
 *   subsequent activations omit it from the table line, but the kernel
 *   still reports it from the superblock.  A reload cannot remove the
 *   flag, so treat it as cosmetic in both directions.
 *
 * - kernel may add tokens LVM did not set (buffer_sectors,
 *   journal_watermark, commit_time, etc.)
 *
 * Skipped tokens are listed in _integrity_skip_p1_token().
 * We verify every non-skipped token we emit exists in the kernel output.
 * Extra kernel tokens are acceptable.
 */

/* Tokens LVM emits that the kernel may legitimately omit */
static int _integrity_skip_p1_token(const char *token, unsigned len)
{
  if (len == 14 && !memcmp(token, "block_size:512", 14))
    return 1;
  if (len == 11 && !memcmp(token, "fix_padding", 11))
    return 1;
  if (len == 11 && !memcmp(token, "recalculate", 11))
    return 1;
  return 0;
}

/* Find exact token in a space-separated string */
static int _integrity_has_token(const char *str, const char *token, unsigned len)
{
  const char *s = str;

  while (*s) {
    const char *e = s;
    while (*e && *e != ' ')
      e++;
    if ((unsigned)(e - s) == len && !memcmp(s, token, len))
      return 1;
    s = (*e == ' ') ? e + 1 : e;
  }

  return 0;
}

/* Advance past one space-separated token */
static const char *_skip_one_token(const char *s)
{
  while (*s && *s != ' ')
    s++;
  while (*s == ' ')
    s++;
  return s;
}

static int _integrity_params_equiv(const char *p1, const char *p2,
           int suspended __attribute__((unused)))
{
  const char *s1 = p1, *s2 = p2;
  const char *e1, *e2;
  const char *args1, *args2;
  const char *tok;
  unsigned len;
  int i;

  /* Compare 4 prefix tokens: dev, start, tag_size, mode */
  for (i = 0; i < 4; i++) {
    e1 = s1;
    while (*e1 && *e1 != ' ')
      e1++;
    e2 = s2;
    while (*e2 && *e2 != ' ')
      e2++;
    if ((e1 - s1) != (e2 - s2) ||
        memcmp(s1, s2, e1 - s1))
      return 0;
    s1 = (*e1 == ' ') ? e1 + 1 : e1;
    s2 = (*e2 == ' ') ? e2 + 1 : e2;
  }

  /* Skip param count (5th token) -- differs due to kernel omissions */
  args1 = _skip_one_token(s1);
  args2 = _skip_one_token(s2);

  /* Fast path */
  if (!strcmp(args1, args2))
    return 1;

  /* Check every non-skipped token we emit exists in kernel output */
  tok = args1;
  while (*tok) {
    e1 = tok;
    while (*e1 && *e1 != ' ')
      e1++;
    len = (unsigned)(e1 - tok);
    if (!_integrity_skip_p1_token(tok, len) &&
        !_integrity_has_token(args2, tok, len))
      return 0;
    tok = (*e1 == ' ') ? e1 + 1 : e1;
  }

  return 1;
}

static int _target_params_equiv(const char *type,
        const char *p1, const char *p2,
        int suspended)
{
  if (!strcmp(type, "raid"))
    return _raid_params_equiv(p1, p2, suspended);

  if (!strcmp(type, "integrity"))
    return _integrity_params_equiv(p1, p2, suspended);

  return 0;
}

static int _reload_with_suppression_v4(struct dm_task *dmt)
{
  struct dm_task *task;
  struct target *t1, *t2;
  size_t len;
  int r;

  /* New task to get existing table information */
  if (!(task = dm_task_create(DM_DEVICE_TABLE))) {
    log_error("Failed to create device-mapper task struct");
    return 0;
  }

  /* Copy across relevant fields */
  if (dmt->dev_name && !dm_task_set_name(task, dmt->dev_name)) {
    dm_task_destroy(task);
    return 0;
  }

  if (dmt->uuid && !dm_task_set_uuid(task, dmt->uuid)) {
    dm_task_destroy(task);
    return 0;
  }

  task->major = dmt->major;
  task->minor = dmt->minor;

  r = dm_task_run(task);

  if (!r) {
    dm_task_destroy(task);
    return r;
  }

  /* Store existing table size */
  t2 = task->head;
  while (t2 && t2->next)
    t2 = t2->next;
  dmt->existing_table_size = t2 ? t2->start + t2->length : 0;

  if (((task->dmi.v4->flags & DM_READONLY_FLAG) ? 1 : 0) != dmt->read_only)
    goto no_match;

  t1 = dmt->head;
  t2 = task->head;

  while (t1 && t2) {
    len = strlen(t2->params);
    while (len-- > 0 && t2->params[len] == ' ')
      t2->params[len] = '\0';

    if (t1->start != t2->start) {
      log_debug("reload %d:%d diff start %llu %llu type %s %s.", task->major, task->minor,
           (unsigned long long)t1->start, (unsigned long long)t2->start, t1->type, t2->type);
      goto no_match;
    }
    if (t1->length != t2->length) {
      log_debug("reload %d:%d diff length %llu %llu type %s %s.", task->major, task->minor,
          (unsigned long long)t1->length, (unsigned long long)t2->length, t1->type, t2->type);
      goto no_match;
    }
    if (strcmp(t1->type, t2->type)) {
      log_debug("reload %d:%d diff type %s %s.", task->major, task->minor, t1->type, t2->type);
      goto no_match;
    }
    if (strcmp(t1->params, t2->params)) {
      if (dmt->skip_reload_params_compare) {
        log_debug("reload %d:%d diff params ignore for type %s.",
            task->major, task->minor, t1->type);
        log_debug("reload params1 %s", t1->params);
        log_debug("reload params2 %s", t2->params);
      } else if (_target_params_equiv(t1->type, t1->params, t2->params,
                 task->dmi.v4->flags & DM_SUSPEND_FLAG)) {
        log_debug("reload %d:%d diff params equiv for type %s.",
            task->major, task->minor, t1->type);
        log_debug("reload params1 %s", t1->params);
        log_debug("reload params2 %s", t2->params);
      } else {
        log_debug("reload %d:%d diff params for type %s.",
            task->major, task->minor, t1->type);
        log_debug("reload params1 %s", t1->params);
        log_debug("reload params2 %s", t2->params);
        goto no_match;
      }
    }

    t1 = t1->next;
    t2 = t2->next;
  }

  if (!t1 && !t2) {
    dmt->dmi.v4 = task->dmi.v4;
    task->dmi.v4 = NULL;
    dm_task_destroy(task);
    return 1;
  }

no_match:
  dm_task_destroy(task);

  /* Now do the original reload */
  dmt->suppress_identical_reload = 0;
  r = dm_task_run(dmt);

  return r;
}

static int _check_children_not_suspended_v4(struct dm_task *dmt, uint64_t device)
{
  struct dm_task *task;
  struct dm_info info;
  struct dm_deps *deps;
  int r = 0;
  uint32_t i;

  /* Find dependencies */
  if (!(task = dm_task_create(DM_DEVICE_DEPS)))
    return 0;

  /* Copy across or set relevant fields */
  if (device) {
    task->major = MAJOR(device);
    task->minor = MINOR(device);
  } else {
    if (dmt->dev_name && !dm_task_set_name(task, dmt->dev_name))
      goto out;

    if (dmt->uuid && !dm_task_set_uuid(task, dmt->uuid))
      goto out;

    task->major = dmt->major;
    task->minor = dmt->minor;
  }

  task->uid = dmt->uid;
  task->gid = dmt->gid;
  task->mode = dmt->mode;
  /* FIXME: Just for udev_check in dm_task_run. Can we avoid this? */
  task->event_nr = dmt->event_nr & DM_UDEV_FLAGS_MASK;
  task->cookie_set = dmt->cookie_set;
  task->add_node = dmt->add_node;

  if (!(r = dm_task_run(task)))
    goto out;

  if (!dm_task_get_info(task, &info) || !info.exists)
    goto out;

  /*
   * Warn if any of the devices this device depends upon are already
   * suspended: I/O could become trapped between the two devices.
   */
  if (info.suspended) {
    if (!device)
      log_debug_activation("Attempting to suspend a device that is already suspended "
               "(%u:%u)", info.major, info.minor);
    else
      log_error(INTERNAL_ERROR "Attempt to suspend device %s%s%s%.0d%s%.0d%s%s"
          "that uses already-suspended device (%u:%u)",
          DEV_NAME(dmt) ? : "", DEV_UUID(dmt) ? : "",
          dmt->major > 0 ? "(" : "",
          dmt->major > 0 ? dmt->major : 0,
          dmt->major > 0 ? ":" : "",
          dmt->minor > 0 ? dmt->minor : 0,
          dmt->major > 0 && dmt->minor == 0 ? "0" : "",
          dmt->major > 0 ? ") " : "",
          info.major, info.minor);

    /* No need for further recursion */
    r = 1;
    goto out;
  }

  if (!(deps = dm_task_get_deps(task)))
    goto out;

  for (i = 0; i < deps->count; i++) {
    /* Only recurse with dm devices */
    if (MAJOR(deps->device[i]) != _dm_device_major)
      continue;

    if (!_check_children_not_suspended_v4(task, deps->device[i]))
      goto out;
  }

  r = 1;

out:
  dm_task_destroy(task);

  return r;
}

static int _suspend_with_validation_v4(struct dm_task *dmt)
{
  /* Avoid recursion */
  dmt->enable_checks = 0;

  /*
   * Ensure we can't leave any I/O trapped between suspended devices.
   */
  if (!_check_children_not_suspended_v4(dmt, 0))
    return 0;

  /* Finally, perform the original suspend. */
  return dm_task_run(dmt);
}

static const char *_sanitise_message(char *message)
{
  const char *sanitised_message = message ?: "";

  /* FIXME: Check for whitespace variations. */
  /* This traps what cryptsetup sends us. */
  if (message && !strncasecmp(message, "key set", 7))
    sanitised_message = "key set";

  return sanitised_message;
}

#ifdef DM_IOCTLS
static int _do_dm_ioctl_unmangle_string(char *str, const char *str_name,
          char *buf, size_t buf_size,
          dm_string_mangling_t mode)
{
  int r;

  if (mode == DM_STRING_MANGLING_NONE)
    return 1;

  if (!check_multiple_mangled_string_allowed(str, str_name, mode))
    return_0;

  if ((r = unmangle_string(str, str_name, strlen(str), buf, buf_size, mode)) < 0) {
    log_debug_activation("_do_dm_ioctl_unmangle_string: failed to "
             "unmangle %s \"%s\"", str_name, str);
    return 0;
  }

  if (r)
    memcpy(str, buf, strlen(buf) + 1);

  return 1;
}

static int _dm_ioctl_unmangle_names(int type, struct dm_ioctl *dmi)
{
  char buf[DM_NAME_LEN];
  char buf_uuid[DM_UUID_LEN];
  struct dm_name_list *names;
  unsigned next = 0;
  char *name;
  int r = 1;
  uint32_t *event_nr;
  char *uuid_ptr;
  dm_string_mangling_t mangling_mode = dm_get_name_mangling_mode();

  if ((name = dmi->name))
    r &= _do_dm_ioctl_unmangle_string(name, "name", buf, sizeof(buf),
              mangling_mode);

  if (type == DM_DEVICE_LIST &&
      ((names = ((struct dm_name_list *) ((char *)dmi + dmi->data_start)))) &&
      names->dev) {
    do {
      names = (struct dm_name_list *)((char *) names + next);
      event_nr = _align_ptr(names->name + strlen(names->name) + 1);
      r &= _do_dm_ioctl_unmangle_string(names->name, "name",
                buf, sizeof(buf), mangling_mode);
      /* Unmangle also UUID within same loop */
      if (_check_has_event_nr() &&
          (event_nr[1] & DM_NAME_LIST_FLAG_HAS_UUID)) {
        uuid_ptr = _align_ptr(event_nr + 2);
        r &= _do_dm_ioctl_unmangle_string(uuid_ptr, "UUID", buf_uuid,
                  sizeof(buf_uuid), mangling_mode);
      }
      next = names->next;
    } while (next);
  }

  return r;
}

static int _dm_ioctl_unmangle_uuids(int type, struct dm_ioctl *dmi)
{
  char buf[DM_UUID_LEN];
  char *uuid = dmi->uuid;

  if (uuid)
    return _do_dm_ioctl_unmangle_string(uuid, "UUID", buf, sizeof(buf),
                dm_get_name_mangling_mode());

  return 1;
}
#endif

/* True for ioctl types that generate a udev event and need cookie handling. */
static inline int _dmt_has_uevent(const struct dm_task *dmt)
{
  return dmt->type == DM_DEVICE_RESUME ||
         dmt->type == DM_DEVICE_REMOVE ||
         dmt->type == DM_DEVICE_RENAME;
}

/*
 * Flatten the task into a fresh dm_ioctl buffer and set all flags and
 * udev cookie bits.  Returns the allocated buffer (caller owns it) or
 * NULL on failure.
 */
static struct dm_ioctl *_dm_task_build_dmi(struct dm_task *dmt,
             unsigned buffer_repeat_count)
{
  struct dm_ioctl *dmi;

  dmi = _flatten(dmt, buffer_repeat_count);
  if (!dmi) {
    log_error("Couldn't create ioctl argument.");
    return NULL;
  }

  if (dmt->type == DM_DEVICE_TABLE)
    dmi->flags |= DM_STATUS_TABLE_FLAG;

  dmi->flags |= DM_EXISTS_FLAG; /* FIXME */

  if (dmt->no_open_count)
    dmi->flags |= DM_SKIP_BDGET_FLAG;

  if (_dmt_has_uevent(dmt) && dm_cookie_supported()) {
    /*
     * Always mark events coming from libdevmapper as
     * "primary sourced". This is needed to distinguish
     * any spurious events so we can act appropriately.
     * This needs to be applied even when udev_sync is
     * not used because udev flags could be used alone.
     */
    dmi->event_nr |= DM_UDEV_PRIMARY_SOURCE_FLAG <<
         DM_UDEV_FLAGS_SHIFT;

    /*
     * Prevent udev vs. libdevmapper race when processing nodes
     * and symlinks. This can happen when the udev rules are
     * installed and udev synchronization code is enabled in
     * libdevmapper but the software using libdevmapper does not
     * make use of it (by not calling dm_task_set_cookie before).
     * We need to instruct the udev rules not to be applied at
     * all in this situation so we can gracefully fallback to
     * libdevmapper's node and symlink creation code.
     */
    if (!dmt->cookie_set && dm_udev_get_sync_support()) {
      log_debug_activation("Cookie value is not set while trying to call %s "
               "ioctl. Please, consider using libdevmapper's udev "
               "synchronization interface or disable it explicitly "
               "by calling dm_udev_set_sync_support(0).",
               dmt->type == DM_DEVICE_RESUME ? "DM_DEVICE_RESUME" :
               dmt->type == DM_DEVICE_REMOVE ? "DM_DEVICE_REMOVE" :
                       "DM_DEVICE_RENAME");
      log_debug_activation("Switching off device-mapper and all subsystem related "
               "udev rules. Falling back to libdevmapper node creation.");
      /*
       * Disable general dm and subsystem rules but keep
       * dm disk rules if not flagged out explicitly before.
       * We need /dev/disk content for the software that expects it.
      */
      dmi->event_nr |= (DM_UDEV_DISABLE_DM_RULES_FLAG |
            DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG) <<
           DM_UDEV_FLAGS_SHIFT;
    }
  }

  log_debug_activation("dm %s %s%s %s%s%s %s%.0d%s%.0d%s"
           "%s[ %s%s%s%s%s%s%s%s%s%s] %.0" PRIu64 " %s [%u]",
           _cmd_data_v4[dmt->type].name,
           dmt->new_uuid ? "UUID " : "",
           dmi->name, dmi->uuid, dmt->newname ? " " : "",
           dmt->newname ? dmt->newname : "",
           dmt->major > 0 ? "(" : "",
           dmt->major > 0 ? dmt->major : 0,
           dmt->major > 0 ? ":" : "",
           dmt->minor > 0 ? dmt->minor : 0,
           dmt->major > 0 && dmt->minor == 0 ? "0" : "",
           dmt->major > 0 ? ") " : "",
           dmt->no_open_count ? "noopencount " : "opencount ",
           dmt->no_flush ? "noflush " : "flush ",
           dmt->read_only ? "readonly " : "",
           dmt->skip_lockfs ? "skiplockfs " : "",
           dmt->retry_remove ? "retryremove " : "",
           dmt->deferred_remove ? "deferredremove " : "",
           dmt->secure_data ? "securedata " : "",
           dmt->ima_measurement ? "ima_measurement " : "",
           dmt->query_inactive_table ? "inactive " : "",
           dmt->enable_checks ? "enablechecks " : "",
           dmt->sector, _sanitise_message(dmt->message),
           dmi->data_size);

  return dmi;
}

/* Execute a single DM ioctl.  Sets dmt->ioctl_errno on failure.
 * Caller must validate dmt->type via _validate_task_type(). */
int dm_ioctl_exec(int fd, struct dm_task *dmt, struct dm_ioctl *dmi)
{
  int r;

  dmt->ioctl_errno = 0;

#ifdef DM_IOCTLS
  r = ioctl(fd, _cmd_data_v4[dmt->type].cmd, dmi);
  if (r < 0)
    dmt->ioctl_errno = errno;
#else /* Userspace alternative for testing */
  r = 0;
#endif
  return r;
}

/*
 * Execute ioctl with EBUSY retry for remove operations.
 *
 * The dmi buffer is reused across retries without rebuilding.
 * On EBUSY the kernel fails the ioctl early without modifying
 * the dmi structure, so the input fields (name, uuid, dev)
 * remain valid for the next attempt.
 */
static int _dm_ioctl_exec_retry(int fd, struct dm_task *dmt)
{
  unsigned retries = 0;
  int r;

  do {
    if (retries) {
      log_debug_activation("EBUSY retry %u/%u for %s.",
               retries, (unsigned) DM_IOCTL_RETRIES,
               dmt->dmi.v4->name);
      usleep(DM_RETRY_USLEEP_DELAY);
    }

    r = dm_ioctl_exec(fd, dmt, dmt->dmi.v4);

    if (r >= 0)
      break;

  } while (dmt->retry_remove &&
     (dmt->ioctl_errno == EBUSY) &&
     (dmt->type == DM_DEVICE_REMOVE) &&
     (++retries <= DM_IOCTL_RETRIES));

  return r;
}

/*
 * Post-ioctl processing: error logging, uevent completion,
 * and name/uuid unmangling.
 * On ioctl error returns 0; caller must call _udev_complete().
 * Calls _udev_complete() only when uevent was not generated by kernel.
 * Returns 1 on success, 0 on failure.
 */
static int _dm_ioctl_post(struct dm_task *dmt, struct dm_ioctl *dmi,
        int r)
{
#ifdef DM_IOCTLS
  if (r < 0 && dmt->expected_errno != dmt->ioctl_errno) {
    if (dmt->ioctl_errno == ENXIO && ((dmt->type == DM_DEVICE_INFO) ||
              (dmt->type == DM_DEVICE_MKNODES) ||
              (dmt->type == DM_DEVICE_STATUS)))
      dmi->flags &= ~DM_EXISTS_FLAG; /* FIXME */
    else {
      if (dmt->ioctl_errno == EINTR)
        log_verbose("device-mapper: %s ioctl on %s %s%s%.0d%s%.0d%s%s "
              "failed: %s",
              _cmd_data_v4[dmt->type].name,
              dmi->name[0] ? dmi->name : DEV_NAME(dmt) ? : "",
              dmi->uuid[0] ? dmi->uuid : DEV_UUID(dmt) ? : "",
              dmt->major > 0 ? "(" : "",
              dmt->major > 0 ? dmt->major : 0,
              dmt->major > 0 ? ":" : "",
              dmt->minor > 0 ? dmt->minor : 0,
              dmt->major > 0 && dmt->minor == 0 ? "0" : "",
              dmt->major > 0 ? ")" : "",
              strerror(dmt->ioctl_errno));
      else
        log_error("device-mapper: %s ioctl on %s %s%s%.0d%s%.0d%s%s "
            "failed: %s",
            _cmd_data_v4[dmt->type].name,
            dmi->name[0] ? dmi->name : DEV_NAME(dmt) ? : "",
            dmi->uuid[0] ? dmi->uuid : DEV_UUID(dmt) ? : "",
            dmt->major > 0 ? "(" : "",
            dmt->major > 0 ? dmt->major : 0,
            dmt->major > 0 ? ":" : "",
            dmt->minor > 0 ? dmt->minor : 0,
            dmt->major > 0 && dmt->minor == 0 ? "0" : "",
            dmt->major > 0 ? ")" : "",
            strerror(dmt->ioctl_errno));

      return 0;
    }
  }

  if (_dmt_has_uevent(dmt) && dm_udev_get_sync_support() &&
      !_check_uevent_generated(dmi)) {
    if (dmt->deferred_remove)
      log_debug_activation("Deferred remove: device busy, "
               "no uevent generated.");
    else {
      log_debug_activation("Uevent not generated! Calling "
               "udev_complete internally to "
               "avoid process lock-up.");
    }
    _udev_complete(dmt);
  }

  if (!_dm_ioctl_unmangle_names(dmt->type, dmi))
    return 0;

  if (dmt->type != DM_DEVICE_REMOVE &&
      !_dm_ioctl_unmangle_uuids(dmt->type, dmi))
    return 0;

#else /* Userspace alternative for testing */
  return 0;
#endif
  return 1;
}

/* Build ioctl buffer, execute it, and post-process the result. */
static struct dm_ioctl *_do_dm_ioctl(struct dm_task *dmt,
             unsigned buffer_repeat_count)
{
  struct dm_ioctl *dmi;
  int r;

  if (!(dmi = _dm_task_build_dmi(dmt, buffer_repeat_count)))
    return_NULL;

  _dm_zfree_dmi(dmt->dmi.v4);
  dmt->dmi.v4 = dmi;

  r = _dm_ioctl_exec_retry(_get_control_fd(), dmt);

  if (dmt->record_timestamp)
    if (!dm_timestamp_get(dmt->ioctl_timestamp))
      stack;

  if (!_dm_ioctl_post(dmt, dmi, r)) {
    _dm_zfree_dmi(dmi);
    dmt->dmi.v4 = NULL;
    return_NULL;
  }

  return dmi;
}

void dm_task_update_nodes(void)
{
  update_devs();
}

/*
 * Perform device-node operations after a successful ioctl.
 * Returns 1 on success, 0 on failure.
 */
static int _dm_task_node_ops(struct dm_task *dmt, struct dm_ioctl *dmi)
{
  const char *dev_name = DEV_NAME(dmt);
  int check_udev = dmt->cookie_set &&
       !(dmt->event_nr >> DM_UDEV_FLAGS_SHIFT &
         DM_UDEV_DISABLE_DM_RULES_FLAG);
  int rely_on_udev = dmt->cookie_set ? (dmt->event_nr >> DM_UDEV_FLAGS_SHIFT &
                DM_UDEV_DISABLE_LIBRARY_FALLBACK) : 0;

  switch (dmt->type) {
  case DM_DEVICE_CREATE:
    if ((dmt->add_node == DM_ADD_NODE_ON_CREATE) &&
        dev_name && *dev_name && !rely_on_udev)
      add_dev_node(dev_name, MAJOR(dmi->dev),
             MINOR(dmi->dev), dmt->uid, dmt->gid,
             dmt->mode, check_udev, rely_on_udev);
    break;
  case DM_DEVICE_REMOVE:
    if (dev_name && !rely_on_udev)
      rm_dev_node(dev_name, check_udev, rely_on_udev);
    break;

  case DM_DEVICE_RENAME:
    if (!dmt->new_uuid && dev_name)
      rename_dev_node(dev_name, dmt->newname,
          check_udev, rely_on_udev);
    break;

  case DM_DEVICE_RESUME:
    if (dev_name && *dev_name) {
      if (dmt->add_node == DM_ADD_NODE_ON_RESUME)
        add_dev_node(dev_name, MAJOR(dmi->dev),
               MINOR(dmi->dev), dmt->uid, dmt->gid,
               dmt->mode, check_udev, rely_on_udev);
      set_dev_node_read_ahead(dev_name,
            MAJOR(dmi->dev), MINOR(dmi->dev),
            dmt->read_ahead, dmt->read_ahead_flags);
    }
    break;

  case DM_DEVICE_MKNODES:
    if (dmi->flags & DM_EXISTS_FLAG)
      add_dev_node(dmi->name, MAJOR(dmi->dev),
             MINOR(dmi->dev), dmt->uid,
             dmt->gid, dmt->mode, 0, rely_on_udev);
    else if (dev_name)
      rm_dev_node(dev_name, 0, rely_on_udev);
    break;

  case DM_DEVICE_STATUS:
  case DM_DEVICE_TABLE:
  case DM_DEVICE_WAITEVENT:
    if (!_unmarshal_status(dmt, dmi))
      return 0;
    break;
  }

  return 1;
}

int dm_task_get_errno(struct dm_task *dmt)
{
  return dmt->ioctl_errno;
}

/*
 * Check whether a DM_BUFFER_FULL_FLAG retry is allowed for this task type.
 * Increments the global doubling factor on success.
 * Returns 1 if the caller should retry with a larger buffer, 0 otherwise.
 */
static int _can_retry_buffer_full(struct dm_task *dmt)
{
  switch (dmt->type) {
  case DM_DEVICE_LIST_VERSIONS:
  case DM_DEVICE_LIST:
  case DM_DEVICE_DEPS:
  case DM_DEVICE_STATUS:
  case DM_DEVICE_TABLE:
  case DM_DEVICE_WAITEVENT:
  case DM_DEVICE_TARGET_MSG:
    break;
  default:
    log_error("libdevmapper buffer too small for data.");
    return 0;
  }

  if (_ioctl_buffer_double_factor >= DM_IOCTL_BUFFER_MAX_DOUBLINGS) {
    log_error("Ioctl buffer maximum reached (16KB << %u = %zu bytes), giving up.",
        _ioctl_buffer_double_factor,
        (size_t)16 * 1024 << _ioctl_buffer_double_factor);
    return 0;
  }

  _ioctl_buffer_double_factor++;

  return 1;
}

#if defined(GNU_SYMVER)
/*
 * Enforce new version 1_02_197 of dm_task_run() that propagates
 * ioctl() errno is being linked to app.
 */
DM_EXPORT_SYMBOL_BASE(dm_task_run)
int dm_task_run_base(struct dm_task *dmt);
int dm_task_run_base(struct dm_task *dmt)
{
  return dm_task_run(dmt);
}
#endif

DM_EXPORT_NEW_SYMBOL(int, dm_task_run, 1_02_197)
  (struct dm_task *dmt)
{
  struct dm_ioctl *dmi;
  int suspended_counter;
  const char *dev_name = DEV_NAME(dmt);
  const char *dev_uuid = DEV_UUID(dmt);

  if (!_validate_task_type(dmt))
    return_0;

  /* Old-style creation had a table supplied */
  if (dmt->type == DM_DEVICE_CREATE && dmt->head)
    return _create_and_load_v4(dmt);

  if (dmt->type == DM_DEVICE_MKNODES && !dev_name &&
      !dev_uuid && dmt->major <= 0)
    return _mknodes_v4(dmt);

  if ((dmt->type == DM_DEVICE_RELOAD) && dmt->suppress_identical_reload)
    return _reload_with_suppression_v4(dmt);

  if ((dmt->type == DM_DEVICE_SUSPEND) && dmt->enable_checks)
    return _suspend_with_validation_v4(dmt);

  if (!_open_control()) {
    _udev_complete(dmt);
    return_0;
  }

  if ((suspended_counter = dm_get_suspended_counter()) &&
      dmt->type == DM_DEVICE_RELOAD)
    log_error(INTERNAL_ERROR "Performing unsafe table load while %d device(s) "
        "are known to be suspended: "
        "%s%s%s %s%.0d%s%.0d%s%s",
        suspended_counter,
        dev_name ? : "",
        dev_uuid ? " UUID " : "",
        dev_uuid ? : "",
        dmt->major > 0 ? "(" : "",
        dmt->major > 0 ? dmt->major : 0,
        dmt->major > 0 ? ":" : "",
        dmt->minor > 0 ? dmt->minor : 0,
        dmt->major > 0 && dmt->minor == 0 ? "0" : "",
        dmt->major > 0 ? ") " : "");

  /* FIXME Detect and warn if cookie set but should not be. */
repeat_ioctl:
  if (!(dmi = _do_dm_ioctl(dmt, _ioctl_buffer_double_factor))) {
    _udev_complete(dmt);
    return_0;
  }

  if (dmi->flags & DM_BUFFER_FULL_FLAG) {
    if (_can_retry_buffer_full(dmt))
      goto repeat_ioctl;

    goto_bad;
  }

  if (!_dm_task_node_ops(dmt, dmi))
    goto_bad;

  return 1;

      bad:
  _dm_zfree_dmi(dmt->dmi.v4);
  dmt->dmi.v4 = NULL;
  return 0;
}

void dm_hold_control_dev(int hold_open)
{
  pthread_mutex_lock(&_control_fd_mutex);
  _hold_control_fd_open = hold_open ? 1 : 0;
  pthread_mutex_unlock(&_control_fd_mutex);

  log_debug("Hold of control device is now %sset.",
      hold_open ? "" : "un");
}

void dm_lib_release(void)
{
  pthread_mutex_lock(&_control_fd_mutex);
  if (!_hold_control_fd_open)
    _close_control_fd();
  pthread_mutex_unlock(&_control_fd_mutex);

  update_devs();
}

void dm_pools_check_leaks(void);

static pthread_once_t _exit_once = PTHREAD_ONCE_INIT;

static void _do_lib_exit(void)
{
  int suspended_counter;

  if ((suspended_counter = dm_get_suspended_counter()))
    log_error("libdevmapper exiting with %d device(s) still suspended.", suspended_counter);

  dm_lib_release();
  selinux_release();
  pthread_mutex_lock(&_control_fd_mutex);
  if (_dm_bitset)
    dm_bitset_destroy(_dm_bitset);
  _dm_bitset = NULL;
  pthread_mutex_unlock(&_control_fd_mutex);
  dm_pools_check_leaks();
  dm_dump_memory();
}

void dm_lib_exit(void)
{
  pthread_once(&_exit_once, _do_lib_exit);
}

#if defined(GNU_SYMVER)
/*
 * Maintain binary backward compatibility.
 * Version script mechanism works with 'gcc' compatible compilers only.
 */

/*
 * This following code is here to retain ABI compatibility after adding
 * the field deferred_remove to struct dm_info in version 1.02.89.
 *
 * Binaries linked against version 1.02.88 of libdevmapper or earlier
 * will use this function that returns dm_info without the
 * deferred_remove field.
 *
 * Binaries compiled against version 1.02.89 onwards will use
 * the new function dm_task_get_info_with_deferred_remove due to the
 * #define.
 *
 * N.B. Keep this function at the end of the file to make sure that
 * no code in this file accidentally calls it.
 */

DM_EXPORT_SYMBOL_BASE(dm_task_get_info)
int dm_task_get_info_base(struct dm_task *dmt, struct dm_info *info);
int dm_task_get_info_base(struct dm_task *dmt, struct dm_info *info)
{
  struct dm_info new_info;

  if (!dm_task_get_info(dmt, &new_info))
    return 0;

  memcpy(info, &new_info, offsetof(struct dm_info, deferred_remove));

  return 1;
}

#endif

int dm_task_get_info_with_deferred_remove(struct dm_task *dmt, struct dm_info *info);
int dm_task_get_info_with_deferred_remove(struct dm_task *dmt, struct dm_info *info)
{
  struct dm_info new_info;

  if (!dm_task_get_info(dmt, &new_info))
    return 0;

  memcpy(info, &new_info, offsetof(struct dm_info, internal_suspend));

  return 1;
}

Coverage Report

Created: 2026-08-12 06:14