* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.

/* $NetBSD: libdm-common.c,v 1.7 2010/12/29 10:39:27 haad Exp $ */

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2007 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/

#include "dmlib.h"
#include "libdm-targets.h"
#include "libdm-common.h"
#ifdef linux
#include "kdev_t.h"
#endif
#include "dm-ioctl.h"

#include <stdarg.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <dirent.h>

#ifdef UDEV_SYNC_SUPPORT
# include <sys/types.h>
# include <sys/ipc.h>
# include <sys/sem.h>
#ifdef HAVE_UDEV_QUEUE_GET_UDEV_IS_ACTIVE
# define LIBUDEV_I_KNOW_THE_API_IS_SUBJECT_TO_CHANGE
# include <libudev.h>
#endif
#endif

#ifdef linux
# include <linux/fs.h>
#endif

#ifdef HAVE_SELINUX
# include <selinux/selinux.h>
#endif

#ifdef __NetBSD__
#include "libdm-netbsd.h"
#endif

#define DEV_DIR "/dev/"

static char _dm_dir[PATH_MAX] = DEV_DIR DM_DIR;

static int _verbose = 0;

#ifdef UDEV_SYNC_SUPPORT
static int _udev_running = -1;
static int _sync_with_udev = 1;
#endif

/*
* Library users can provide their own logging
* function.
*/

static void _default_log_line(int level,
const char *file __attribute((unused)),
int line __attribute((unused)), int dm_errno,
const char *f, va_list ap)
{
int use_stderr = level & _LOG_STDERR;

level &= ~_LOG_STDERR;

if (level > _LOG_WARN && !_verbose)
return;

if (level < _LOG_WARN)
vfprintf(stderr, f, ap);
else
vfprintf(use_stderr ? stderr : stdout, f, ap);

if (level < _LOG_WARN)
fprintf(stderr, "\n");
else
fprintf(use_stderr ? stderr : stdout, "\n");
}

static void _default_log_with_errno(int level,
const char *file __attribute((unused)),
int line __attribute((unused)), int dm_errno,
const char *f, ...)
{
va_list ap;

va_start(ap, f);
_default_log_line(level, file, line, dm_errno, f, ap);
va_end(ap);
}

static void _default_log(int level, const char *file,
int line, const char *f, ...)
{
va_list ap;

va_start(ap, f);
_default_log_line(level, file, line, 0, f, ap);
va_end(ap);
}

dm_log_fn dm_log = _default_log;
dm_log_with_errno_fn dm_log_with_errno = _default_log_with_errno;

void dm_log_init(dm_log_fn fn)
{
if (fn)
dm_log = fn;
else
dm_log = _default_log;

dm_log_with_errno = _default_log_with_errno;
}

int dm_log_is_non_default(void)
{
return (dm_log == _default_log) ? 0 : 1;
}

void dm_log_with_errno_init(dm_log_with_errno_fn fn)
{
if (fn)
dm_log_with_errno = fn;
else
dm_log_with_errno = _default_log_with_errno;

dm_log = _default_log;
}

void dm_log_init_verbose(int level)
{
_verbose = level;
}

static void _build_dev_path(char *buffer, size_t len, const char *dev_name)
{
/* If there's a /, assume caller knows what they're doing */
if (strchr(dev_name, '/'))
snprintf(buffer, len, "%s", dev_name);
else
snprintf(buffer, len, "%s/%s", _dm_dir, dev_name);
}

int dm_get_library_version(char *version, size_t size)
{
strncpy(version, DM_LIB_VERSION, size);
return 1;
}

struct dm_task *dm_task_create(int type)
{
struct dm_task *dmt = dm_malloc(sizeof(*dmt));

if (!dmt) {
log_error("dm_task_create: malloc(%" PRIsize_t ") failed",
sizeof(*dmt));
return NULL;
}

if (!dm_check_version()) {
dm_free(dmt);
return NULL;
}

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

dmt->type = type;
dmt->minor = -1;
dmt->major = -1;
dmt->allow_default_major_fallback = 1;
dmt->uid = DM_DEVICE_UID;
dmt->gid = DM_DEVICE_GID;
dmt->mode = DM_DEVICE_MODE;
dmt->no_open_count = 0;
dmt->read_ahead = DM_READ_AHEAD_AUTO;
dmt->read_ahead_flags = 0;
dmt->event_nr = 0;
dmt->cookie_set = 0;
dmt->query_inactive_table = 0;

return dmt;
}

/*
* Find the name associated with a given device number by scanning _dm_dir.
*/
static char *_find_dm_name_of_device(dev_t st_rdev)
{
const char *name;
char path[PATH_MAX];
struct dirent *dirent;
DIR *d;
struct stat buf;
char *new_name = NULL;

if (!(d = opendir(_dm_dir))) {
log_sys_error("opendir", _dm_dir);
return NULL;
}

while ((dirent = readdir(d))) {
name = dirent->d_name;

if (!strcmp(name, ".") || !strcmp(name, ".."))
continue;

if (dm_snprintf(path, sizeof(path), "%s/%s", _dm_dir,
name) == -1) {
log_error("Couldn't create path for %s", name);
continue;
}

if (stat(path, &buf))
continue;

if (buf.st_rdev == st_rdev) {
if (!(new_name = dm_strdup(name)))
log_error("dm_task_set_name: strdup(%s) failed",
name);
break;
}
}

if (closedir(d))
log_sys_error("closedir", _dm_dir);

return new_name;
}

int dm_task_set_name(struct dm_task *dmt, const char *name)
{
char *pos;
char *new_name = NULL;
char path[PATH_MAX];
struct stat st1, st2;

if (dmt->dev_name) {
dm_free(dmt->dev_name);
dmt->dev_name = NULL;
}

/*
* Path supplied for existing device?
*/
if ((pos = strrchr(name, '/'))) {
if (dmt->type == DM_DEVICE_CREATE) {
log_error("Name \"%s\" invalid. It contains \"/\".", name);
return 0;
}

if (stat(name, &st1)) {
log_error("Device %s not found", name);
return 0;
}

/*
* If supplied path points to same device as last component
* under /dev/mapper, use that name directly. Otherwise call
* _find_dm_name_of_device() to scan _dm_dir for a match.
*/
if (dm_snprintf(path, sizeof(path), "%s/%s", _dm_dir,
pos + 1) == -1) {
log_error("Couldn't create path for %s", pos + 1);
return 0;
}

if (!stat(path, &st2) && (st1.st_rdev == st2.st_rdev))
name = pos + 1;
else if ((new_name = _find_dm_name_of_device(st1.st_rdev)))
name = new_name;
else {
log_error("Device %s not found", name);
return 0;
}
}

if (strlen(name) >= DM_NAME_LEN) {
log_error("Name \"%s\" too long", name);
if (new_name)
dm_free(new_name);
return 0;
}

if (new_name)
dmt->dev_name = new_name;
else if (!(dmt->dev_name = dm_strdup(name))) {
log_error("dm_task_set_name: strdup(%s) failed", name);
return 0;
}

return 1;
}

int dm_task_set_uuid(struct dm_task *dmt, const char *uuid)
{
if (dmt->uuid) {
dm_free(dmt->uuid);
dmt->uuid = NULL;
}

if (!(dmt->uuid = dm_strdup(uuid))) {
log_error("dm_task_set_uuid: strdup(%s) failed", uuid);
return 0;
}

return 1;
}

int dm_task_set_major(struct dm_task *dmt, int major)
{
dmt->major = major;
dmt->allow_default_major_fallback = 0;

return 1;
}

int dm_task_set_minor(struct dm_task *dmt, int minor)
{
dmt->minor = minor;

return 1;
}

int dm_task_set_major_minor(struct dm_task *dmt, int major, int minor,
int allow_default_major_fallback)
{
dmt->major = major;
dmt->minor = minor;
dmt->allow_default_major_fallback = allow_default_major_fallback;

return 1;
}

int dm_task_set_uid(struct dm_task *dmt, uid_t uid)
{
dmt->uid = uid;

return 1;
}

int dm_task_set_gid(struct dm_task *dmt, gid_t gid)
{
dmt->gid = gid;

return 1;
}

int dm_task_set_mode(struct dm_task *dmt, mode_t mode)
{
dmt->mode = mode;

return 1;
}

int dm_task_add_target(struct dm_task *dmt, uint64_t start, uint64_t size,
const char *ttype, const char *params)
{
struct target *t = create_target(start, size, ttype, params);

if (!t)
return 0;

if (!dmt->head)
dmt->head = dmt->tail = t;
else {
dmt->tail->next = t;
dmt->tail = t;
}

return 1;
}

int dm_set_selinux_context(const char *path, mode_t mode)
{
#ifdef HAVE_SELINUX
security_context_t scontext;

if (is_selinux_enabled() <= 0)
return 1;

if (matchpathcon(path, mode, &scontext) < 0) {
log_error("%s: matchpathcon %07o failed: %s", path, mode,
strerror(errno));
return 0;
}

log_debug("Setting SELinux context for %s to %s.", path, scontext);

if ((lsetfilecon(path, scontext) < 0) && (errno != ENOTSUP)) {
log_sys_error("lsetfilecon", path);
freecon(scontext);
return 0;
}

freecon(scontext);
#endif
return 1;
}

static int _add_dev_node(const char *dev_name, uint32_t major, uint32_t minor,
uid_t uid, gid_t gid, mode_t mode, int check_udev)
{
char path[PATH_MAX];
struct stat info;
dev_t dev = MKDEV(major, minor);
mode_t old_mask;

#ifdef __NetBSD__
char rpath[PATH_MAX];
uint32_t raw_major;
dev_t rdev;
char raw_devname[DM_NAME_LEN+1]; /* r + other device name */

nbsd_get_dm_major(&raw_major, DM_CHAR_MAJOR);
rdev = MKDEV(raw_major, minor);

snprintf(raw_devname, sizeof(raw_devname), "r%s", dev_name);

_build_dev_path(rpath, sizeof(rpath), raw_devname);

if (stat(rpath, &info) >= 0) {
if (!S_ISCHR(info.st_mode)) {
log_error("A non-raw device file at '%s' "
"is already present", rpath);
return 0;
}

/* If right inode already exists we don't touch uid etc. */
if (info.st_rdev == rdev)
return 1;

if (unlink(rpath) < 0) {
log_error("Unable to unlink device node for '%s'",
raw_devname);
return 0;
}
}

old_mask = umask(0);
if (mknod(rpath, S_IFCHR | mode, rdev) < 0) {
umask(old_mask);
log_error("Unable to make device node for '%s'", raw_devname);
return 0;
}
umask(old_mask);

if (chown(rpath, uid, gid) < 0) {
log_sys_error("Raw device chown", rpath);
return 0;
}
#endif

_build_dev_path(path, sizeof(path), dev_name);

if (stat(path, &info) >= 0) {
if (!S_ISBLK(info.st_mode)) {
log_error("A non-block device file at '%s' "
"is already present", path);
return 0;
}

/* If right inode already exists we don't touch uid etc. */
if (info.st_rdev == dev)
return 1;

if (unlink(path) < 0) {
log_error("Unable to unlink device node for '%s'",
dev_name);
return 0;
}
} else if (dm_udev_get_sync_support() && check_udev)
log_warn("%s not set up by udev: Falling back to direct "
"node creation.", path);

old_mask = umask(0);
if (mknod(path, S_IFBLK | mode, dev) < 0) {
umask(old_mask);
log_error("Unable to make device node for '%s'", dev_name);
return 0;
}
umask(old_mask);

if (chown(path, uid, gid) < 0) {
log_sys_error("chown", path);
return 0;
}

log_debug("Created %s", path);

if (!dm_set_selinux_context(path, S_IFBLK))
return 0;

return 1;
}

static int _rm_dev_node(const char *dev_name, int check_udev)
{
char path[PATH_MAX];
struct stat info;

#ifdef __NetBSD__
char rpath[PATH_MAX];
char raw_devname[DM_NAME_LEN+1]; /* r + other device name */

snprintf(raw_devname,sizeof(raw_devname),"r%s",dev_name);

_build_dev_path(rpath, sizeof(rpath), raw_devname);

if (stat(rpath, &info) < 0)
return 1;

if (unlink(rpath) < 0) {
log_error("Unable to unlink device node for '%s'", raw_devname);
return 0;
}

log_debug("Removed %s", rpath);
#endif

_build_dev_path(path, sizeof(path), dev_name);

if (stat(path, &info) < 0)
return 1;
else if (dm_udev_get_sync_support() && check_udev)
log_warn("Node %s was not removed by udev. "
"Falling back to direct node removal.", path);

if (unlink(path) < 0) {
log_error("Unable to unlink device node for '%s'", dev_name);
return 0;
}

log_debug("Removed %s", path);

return 1;
}

static int _rename_dev_node(const char *old_name, const char *new_name,
int check_udev)
{
char oldpath[PATH_MAX];
char newpath[PATH_MAX];
struct stat info;

#ifdef __NetBSD__
char rpath[PATH_MAX];
char nrpath[PATH_MAX];
char raw_devname[DM_NAME_LEN+1]; /* r + other device name */
char nraw_devname[DM_NAME_LEN+1]; /* r + other device name */

snprintf(nraw_devname,sizeof(raw_devname),"r%s",new_name);
snprintf(raw_devname,sizeof(raw_devname),"r%s",old_name);

_build_dev_path(nrpath, sizeof(nrpath), nraw_devname);
_build_dev_path(rpath, sizeof(rpath), raw_devname);

if (stat(nrpath, &info) == 0) {
if (S_ISBLK(info.st_mode)) {
log_error("A block device file at '%s' "
"is present where raw device should be.", newpath);
return 0;
}

if (unlink(nrpath) < 0) {
log_error("Unable to unlink device node for '%s'",
nraw_devname);
return 0;
}
}

if (rename(rpath, nrpath) < 0) {
log_error("Unable to rename device node from '%s' to '%s'",
raw_devname, nraw_devname);
return 0;
}

log_debug("Renamed %s to %s", rpath, nrpath);

#endif

_build_dev_path(oldpath, sizeof(oldpath), old_name);
_build_dev_path(newpath, sizeof(newpath), new_name);

if (stat(newpath, &info) == 0) {
if (!S_ISBLK(info.st_mode)) {
log_error("A non-block device file at '%s' "
"is already present", newpath);
return 0;
}
else if (dm_udev_get_sync_support() && check_udev) {
if (stat(oldpath, &info) < 0 &&
errno == ENOENT)
/* assume udev already deleted this */
return 1;
else {
log_warn("The node %s should have been renamed to %s "
"by udev but old node is still present. "
"Falling back to direct old node removal.",
oldpath, newpath);
return _rm_dev_node(old_name, 0);
}
}

if (unlink(newpath) < 0) {
if (errno == EPERM) {
/* devfs, entry has already been renamed */
return 1;
}
log_error("Unable to unlink device node for '%s'",
new_name);
return 0;
}
}
else if (dm_udev_get_sync_support() && check_udev)
log_warn("The node %s should have been renamed to %s "
"by udev but new node is not present. "
"Falling back to direct node rename.",
oldpath, newpath);

if (rename(oldpath, newpath) < 0) {
log_error("Unable to rename device node from '%s' to '%s'",
old_name, new_name);
return 0;
}

log_debug("Renamed %s to %s", oldpath, newpath);

return 1;
}

#ifdef linux
static int _open_dev_node(const char *dev_name)
{
int fd = -1;
char path[PATH_MAX];

_build_dev_path(path, sizeof(path), dev_name);

if ((fd = open(path, O_RDONLY, 0)) < 0)
log_sys_error("open", path);

return fd;
}

int get_dev_node_read_ahead(const char *dev_name, uint32_t *read_ahead)
{
int r = 1;
int fd;
long read_ahead_long;

if (!*dev_name) {
log_error("Empty device name passed to BLKRAGET");
return 0;
}

if ((fd = _open_dev_node(dev_name)) < 0)
return_0;

if (ioctl(fd, BLKRAGET, &read_ahead_long)) {
log_sys_error("BLKRAGET", dev_name);
*read_ahead = 0;
r = 0;
} else {
*read_ahead = (uint32_t) read_ahead_long;
log_debug("%s: read ahead is %" PRIu32, dev_name, *read_ahead);
}

if (close(fd))
stack;

return r;
}

static int _set_read_ahead(const char *dev_name, uint32_t read_ahead)
{
int r = 1;
int fd;
long read_ahead_long = (long) read_ahead;

if (!*dev_name) {
log_error("Empty device name passed to BLKRAGET");
return 0;
}

if ((fd = _open_dev_node(dev_name)) < 0)
return_0;

log_debug("%s: Setting read ahead to %" PRIu32, dev_name, read_ahead);

if (ioctl(fd, BLKRASET, read_ahead_long)) {
log_sys_error("BLKRASET", dev_name);
r = 0;
}

if (close(fd))
stack;

return r;
}

static int _set_dev_node_read_ahead(const char *dev_name, uint32_t read_ahead,
uint32_t read_ahead_flags)
{
uint32_t current_read_ahead;

if (read_ahead == DM_READ_AHEAD_AUTO)
return 1;

if (read_ahead == DM_READ_AHEAD_NONE)
read_ahead = 0;

if (read_ahead_flags & DM_READ_AHEAD_MINIMUM_FLAG) {
if (!get_dev_node_read_ahead(dev_name, &current_read_ahead))
return_0;

if (current_read_ahead > read_ahead) {
log_debug("%s: retaining kernel read ahead of %" PRIu32
" (requested %" PRIu32 ")",
dev_name, current_read_ahead, read_ahead);
return 1;
}
}

return _set_read_ahead(dev_name, read_ahead);
}

#else

int get_dev_node_read_ahead(const char *dev_name, uint32_t *read_ahead)
{
*read_ahead = 0;

return 1;
}

static int _set_dev_node_read_ahead(const char *dev_name, uint32_t read_ahead,
uint32_t read_ahead_flags)
{
return 1;
}
#endif

typedef enum {
NODE_ADD,
NODE_DEL,
NODE_RENAME,
NODE_READ_AHEAD
} node_op_t;

static int _do_node_op(node_op_t type, const char *dev_name, uint32_t major,
uint32_t minor, uid_t uid, gid_t gid, mode_t mode,
const char *old_name, uint32_t read_ahead,
uint32_t read_ahead_flags, int check_udev)
{
switch (type) {
case NODE_ADD:
return _add_dev_node(dev_name, major, minor, uid, gid,
mode, check_udev);
case NODE_DEL:
return _rm_dev_node(dev_name, check_udev);
case NODE_RENAME:
return _rename_dev_node(old_name, dev_name, check_udev);
case NODE_READ_AHEAD:
return _set_dev_node_read_ahead(dev_name, read_ahead,
read_ahead_flags);
}

return 1;
}

static DM_LIST_INIT(_node_ops);

struct node_op_parms {
struct dm_list list;
node_op_t type;
char *dev_name;
uint32_t major;
uint32_t minor;
uid_t uid;
gid_t gid;
mode_t mode;
uint32_t read_ahead;
uint32_t read_ahead_flags;
char *old_name;
int check_udev;
char names[0];
};

static void _store_str(char **pos, char **ptr, const char *str)
{
strcpy(*pos, str);
*ptr = *pos;
*pos += strlen(*ptr) + 1;
}

static int _stack_node_op(node_op_t type, const char *dev_name, uint32_t major,
uint32_t minor, uid_t uid, gid_t gid, mode_t mode,
const char *old_name, uint32_t read_ahead,
uint32_t read_ahead_flags, int check_udev)
{
struct node_op_parms *nop;
struct dm_list *noph, *nopht;
size_t len = strlen(dev_name) + strlen(old_name) + 2;
char *pos;

/*
* Ignore any outstanding operations on the node if deleting it
*/
if (type == NODE_DEL) {
dm_list_iterate_safe(noph, nopht, &_node_ops) {
nop = dm_list_item(noph, struct node_op_parms);
if (!strcmp(dev_name, nop->dev_name)) {
dm_list_del(&nop->list);
dm_free(nop);
}
}
}

if (!(nop = dm_malloc(sizeof(*nop) + len))) {
log_error("Insufficient memory to stack mknod operation");
return 0;
}

pos = nop->names;
nop->type = type;
nop->major = major;
nop->minor = minor;
nop->uid = uid;
nop->gid = gid;
nop->mode = mode;
nop->read_ahead = read_ahead;
nop->read_ahead_flags = read_ahead_flags;
nop->check_udev = check_udev;

_store_str(&pos, &nop->dev_name, dev_name);
_store_str(&pos, &nop->old_name, old_name);

dm_list_add(&_node_ops, &nop->list);

return 1;
}

static void _pop_node_ops(void)
{
struct dm_list *noph, *nopht;
struct node_op_parms *nop;

dm_list_iterate_safe(noph, nopht, &_node_ops) {
nop = dm_list_item(noph, struct node_op_parms);
_do_node_op(nop->type, nop->dev_name, nop->major, nop->minor,
nop->uid, nop->gid, nop->mode, nop->old_name,
nop->read_ahead, nop->read_ahead_flags,
nop->check_udev);
dm_list_del(&nop->list);
dm_free(nop);
}
}

int add_dev_node(const char *dev_name, uint32_t major, uint32_t minor,
uid_t uid, gid_t gid, mode_t mode, int check_udev)
{
log_debug("%s: Stacking NODE_ADD (%" PRIu32 ",%" PRIu32 ") %u:%u 0%o",
dev_name, major, minor, uid, gid, mode);

return _stack_node_op(NODE_ADD, dev_name, major, minor, uid,
gid, mode, "", 0, 0, check_udev);
}

int rename_dev_node(const char *old_name, const char *new_name, int check_udev)
{
log_debug("%s: Stacking NODE_RENAME to %s", old_name, new_name);

return _stack_node_op(NODE_RENAME, new_name, 0, 0, 0,
0, 0, old_name, 0, 0, check_udev);
}

int rm_dev_node(const char *dev_name, int check_udev)
{
log_debug("%s: Stacking NODE_DEL (replaces other stacked ops)", dev_name);

return _stack_node_op(NODE_DEL, dev_name, 0, 0, 0,
0, 0, "", 0, 0, check_udev);
}

int set_dev_node_read_ahead(const char *dev_name, uint32_t read_ahead,
uint32_t read_ahead_flags)
{
if (read_ahead == DM_READ_AHEAD_AUTO)
return 1;

log_debug("%s: Stacking NODE_READ_AHEAD %" PRIu32 " (flags=%" PRIu32
")", dev_name, read_ahead, read_ahead_flags);

return _stack_node_op(NODE_READ_AHEAD, dev_name, 0, 0, 0, 0,
0, "", read_ahead, read_ahead_flags, 0);
}

void update_devs(void)
{
_pop_node_ops();
}

int dm_set_dev_dir(const char *dev_dir)
{
size_t len;
const char *slash;
if (*dev_dir != '/') {
log_debug("Invalid dev_dir value, %s: "
"not an absolute name.", dev_dir);
return 0;
}

len = strlen(dev_dir);
slash = dev_dir[len-1] == '/' ? "" : "/";

if (snprintf(_dm_dir, sizeof _dm_dir, "%s%s%s", dev_dir, slash, DM_DIR)
>= sizeof _dm_dir) {
log_debug("Invalid dev_dir value, %s: name too long.", dev_dir);
return 0;
}

return 1;
}

const char *dm_dir(void)
{
return _dm_dir;
}

int dm_mknodes(const char *name)
{
struct dm_task *dmt;
int r = 0;

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

if (name && !dm_task_set_name(dmt, name))
goto out;

if (!dm_task_no_open_count(dmt))
goto out;

r = dm_task_run(dmt);

out:
dm_task_destroy(dmt);
return r;
}

int dm_driver_version(char *version, size_t size)
{
struct dm_task *dmt;
int r = 0;

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

if (!dm_task_run(dmt))
log_error("Failed to get driver version");

if (!dm_task_get_driver_version(dmt, version, size))
goto out;

r = 1;

out:
dm_task_destroy(dmt);
return r;
}

#ifndef UDEV_SYNC_SUPPORT
void dm_udev_set_sync_support(int sync_with_udev)
{
}

int dm_udev_get_sync_support(void)
{
return 0;
}

int dm_task_set_cookie(struct dm_task *dmt, uint32_t *cookie, uint16_t flags)
{
if (dm_cookie_supported())
dmt->event_nr = flags << DM_UDEV_FLAGS_SHIFT;
*cookie = 0;

return 1;
}

int dm_udev_complete(uint32_t cookie)
{
return 1;
}

int dm_udev_wait(uint32_t cookie)
{
return 1;
}

#else /* UDEV_SYNC_SUPPORT */

static int _check_udev_is_running(void)
{

# ifndef HAVE_UDEV_QUEUE_GET_UDEV_IS_ACTIVE

log_debug("Could not get udev state because libudev library "
"was not found and it was not compiled in. "
"Assuming udev is not running.");
return 0;

# else /* HAVE_UDEV_QUEUE_GET_UDEV_IS_ACTIVE */

struct udev *udev;
struct udev_queue *udev_queue;
int r;

if (!(udev = udev_new()))
goto_bad;

if (!(udev_queue = udev_queue_new(udev))) {
udev_unref(udev);
goto_bad;
}

if (!(r = udev_queue_get_udev_is_active(udev_queue)))
log_debug("Udev is not running. "
"Not using udev synchronisation code.");

udev_queue_unref(udev_queue);
udev_unref(udev);

return r;

bad:
log_error("Could not get udev state. Assuming udev is not running.");
return 0;

# endif /* HAVE_UDEV_QUEUE_GET_UDEV_IS_ACTIVE */

}

void dm_udev_set_sync_support(int sync_with_udev)
{
if (_udev_running < 0)
_udev_running = _check_udev_is_running();

_sync_with_udev = sync_with_udev;
}

int dm_udev_get_sync_support(void)
{
if (_udev_running < 0)
_udev_running = _check_udev_is_running();

return dm_cookie_supported() && _udev_running && _sync_with_udev;
}

static int _get_cookie_sem(uint32_t cookie, int *semid)
{
if (cookie >> 16 != DM_COOKIE_MAGIC) {
log_error("Could not continue to access notification "
"semaphore identified by cookie value %"
PRIu32 " (0x%x). Incorrect cookie prefix.",
cookie, cookie);
return 0;
}

if ((*semid = semget((key_t) cookie, 1, 0)) >= 0)
return 1;

switch (errno) {
case ENOENT:
log_error("Could not find notification "
"semaphore identified by cookie "
"value %" PRIu32 " (0x%x)",
cookie, cookie);
break;
case EACCES:
log_error("No permission to access "
"notificaton semaphore identified "
"by cookie value %" PRIu32 " (0x%x)",
cookie, cookie);
break;
default:
log_error("Failed to access notification "
"semaphore identified by cookie "
"value %" PRIu32 " (0x%x): %s",
cookie, cookie, strerror(errno));
break;
}

return 0;
}

static int _udev_notify_sem_inc(uint32_t cookie, int semid)
{
struct sembuf sb = {0, 1, 0};

if (semop(semid, &sb, 1) < 0) {
log_error("semid %d: semop failed for cookie 0x%" PRIx32 ": %s",
semid, cookie, strerror(errno));
return 0;
}

log_debug("Udev cookie 0x%" PRIx32 " (semid %d) incremented",
cookie, semid);

return 1;
}

static int _udev_notify_sem_dec(uint32_t cookie, int semid)
{
struct sembuf sb = {0, -1, IPC_NOWAIT};

if (semop(semid, &sb, 1) < 0) {
switch (errno) {
case EAGAIN:
log_error("semid %d: semop failed for cookie "
"0x%" PRIx32 ": "
"incorrect semaphore state",
semid, cookie);
break;
default:
log_error("semid %d: semop failed for cookie "
"0x%" PRIx32 ": %s",
semid, cookie, strerror(errno));
break;
}
return 0;
}

log_debug("Udev cookie 0x%" PRIx32 " (semid %d) decremented",
cookie, semid);

return 1;
}

static int _udev_notify_sem_destroy(uint32_t cookie, int semid)
{
if (semctl(semid, 0, IPC_RMID, 0) < 0) {
log_error("Could not cleanup notification semaphore "
"identified by cookie value %" PRIu32 " (0x%x): %s",
cookie, cookie, strerror(errno));
return 0;
}

log_debug("Udev cookie 0x%" PRIx32 " (semid %d) destroyed", cookie,
semid);

return 1;
}

static int _udev_notify_sem_create(uint32_t *cookie, int *semid)
{
int fd;
int gen_semid;
uint16_t base_cookie;
uint32_t gen_cookie;

if ((fd = open("/dev/urandom", O_RDONLY)) < 0) {
log_error("Failed to open /dev/urandom "
"to create random cookie value");
*cookie = 0;
return 0;
}

/* Generate random cookie value. Be sure it is unique and non-zero. */
do {
/* FIXME Handle non-error returns from read(). Move _io() into libdm? */
if (read(fd, &base_cookie, sizeof(base_cookie)) != sizeof(base_cookie)) {
log_error("Failed to initialize notification cookie");
goto bad;
}

gen_cookie = DM_COOKIE_MAGIC << 16 | base_cookie;

if (base_cookie && (gen_semid = semget((key_t) gen_cookie,
1, 0600 | IPC_CREAT | IPC_EXCL)) < 0) {
switch (errno) {
case EEXIST:
/* if the semaphore key exists, we
* simply generate another random one */
base_cookie = 0;
break;
case ENOMEM:
log_error("Not enough memory to create "
"notification semaphore");
goto bad;
case ENOSPC:
log_error("Limit for the maximum number "
"of semaphores reached. You can "
"check and set the limits in "
"/proc/sys/kernel/sem.");
goto bad;
default:
log_error("Failed to create notification "
"semaphore: %s", strerror(errno));
goto bad;
}
}
} while (!base_cookie);

log_debug("Udev cookie 0x%" PRIx32 " (semid %d) created",
gen_cookie, gen_semid);

if (semctl(gen_semid, 0, SETVAL, 1) < 0) {
log_error("semid %d: semctl failed: %s", gen_semid, strerror(errno));
/* We have to destroy just created semaphore
* so it won't stay in the system. */
(void) _udev_notify_sem_destroy(gen_cookie, gen_semid);
goto bad;
}

log_debug("Udev cookie 0x%" PRIx32 " (semid %d) incremented",
gen_cookie, gen_semid);

if (close(fd))
stack;

*semid = gen_semid;
*cookie = gen_cookie;

return 1;

bad:
if (close(fd))
stack;

*cookie = 0;

return 0;
}

int dm_task_set_cookie(struct dm_task *dmt, uint32_t *cookie, uint16_t flags)
{
int semid;

if (dm_cookie_supported())
dmt->event_nr = flags << DM_UDEV_FLAGS_SHIFT;

if (!dm_udev_get_sync_support()) {
*cookie = 0;
return 1;
}

if (*cookie) {
if (!_get_cookie_sem(*cookie, &semid))
goto_bad;
} else if (!_udev_notify_sem_create(cookie, &semid))
goto_bad;

if (!_udev_notify_sem_inc(*cookie, semid)) {
log_error("Could not set notification semaphore "
"identified by cookie value %" PRIu32 " (0x%x)",
*cookie, *cookie);
goto bad;
}

dmt->event_nr |= ~DM_UDEV_FLAGS_MASK & *cookie;
dmt->cookie_set = 1;

log_debug("Udev cookie 0x%" PRIx32 " (semid %d) assigned to dm_task "
"with flags 0x%" PRIx16, *cookie, semid, flags);

return 1;

bad:
dmt->event_nr = 0;
return 0;
}

int dm_udev_complete(uint32_t cookie)
{
int semid;

if (!cookie || !dm_udev_get_sync_support())
return 1;

if (!_get_cookie_sem(cookie, &semid))
return_0;

if (!_udev_notify_sem_dec(cookie, semid)) {
log_error("Could not signal waiting process using notification "
"semaphore identified by cookie value %" PRIu32 " (0x%x)",
cookie, cookie);
return 0;
}

return 1;
}

int dm_udev_wait(uint32_t cookie)
{
int semid;
struct sembuf sb = {0, 0, 0};

if (!cookie || !dm_udev_get_sync_support())
return 1;

if (!_get_cookie_sem(cookie, &semid))
return_0;

if (!_udev_notify_sem_dec(cookie, semid)) {
log_error("Failed to set a proper state for notification "
"semaphore identified by cookie value %" PRIu32 " (0x%x) "
"to initialize waiting for incoming notifications.",
cookie, cookie);
(void) _udev_notify_sem_destroy(cookie, semid);
return 0;
}

log_debug("Udev cookie 0x%" PRIx32 " (semid %d): Waiting for zero",
cookie, semid);

repeat_wait:
if (semop(semid, &sb, 1) < 0) {
if (errno == EINTR)
goto repeat_wait;
else if (errno == EIDRM)
return 1;

log_error("Could not set wait state for notification semaphore "
"identified by cookie value %" PRIu32 " (0x%x): %s",
cookie, cookie, strerror(errno));
(void) _udev_notify_sem_destroy(cookie, semid);
return 0;
}

return _udev_notify_sem_destroy(cookie, semid);
}

#endif /* UDEV_SYNC_SUPPORT */