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lvm2/libdm/libdm-common.c
Alasdair Kergon 1840aa0974 Maintain a count of the number of suspended devices in libdevmapper 
and use this for the LVM critical section logic.  Also report an error if
code tries to load a table while any device is known to be in the
suspended state.
(If the variety of problems these changes are showing up can't be fixed
before the next release, the error messages can be reduced to debug
level.)
2011-06-13 03:32:45 +00:00

1461 lines
31 KiB
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/*
* 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"
#include "kdev_t.h"
#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>
# include <libudev.h>
#endif
#ifdef linux
# include <linux/fs.h>
#endif
#ifdef HAVE_SELINUX
# include <selinux/selinux.h>
#endif
#ifdef HAVE_SELINUX_LABEL_H
# include <selinux/label.h>
#endif
#define DEV_DIR "/dev/"
#ifdef UDEV_SYNC_SUPPORT
#ifdef _SEM_SEMUN_UNDEFINED
union semun
{
int val; /* value for SETVAL */
struct semid_ds *buf; /* buffer for IPC_STAT & IPC_SET */
unsigned short int *array; /* array for GETALL & SETALL */
struct seminfo *__buf; /* buffer for IPC_INFO */
};
#endif
#endif
static char _dm_dir[PATH_MAX] = DEV_DIR DM_DIR;
static int _verbose = 0;
static int _suspended_dev_counter = 0;
#ifdef HAVE_SELINUX_LABEL_H
static struct selabel_handle *_selabel_handle = NULL;
#endif
#ifdef UDEV_SYNC_SUPPORT
static int _semaphore_supported = -1;
static int _udev_running = -1;
static int _sync_with_udev = 1;
static int _udev_checking = 1;
#endif
/*
* Library users can provide their own logging
* function.
*/
__attribute__((format(printf, 5, 0)))
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");
}
__attribute__((format(printf, 5, 6)))
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);
}
__attribute__((format(printf, 4, 5)))
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;
}
void inc_suspended(void)
{
_suspended_dev_counter++;
log_debug("Suspended device counter increased to %d", _suspended_dev_counter);
}
void dec_suspended(void)
{
if (!_suspended_dev_counter) {
log_error("Attempted to decrement suspended device counter below zero.");
return;
}
_suspended_dev_counter--;
log_debug("Suspended device counter reduced to %d", _suspended_dev_counter);
}
int dm_get_suspended_counter(void)
{
return _suspended_dev_counter;
}
struct dm_task *dm_task_create(int type)
{
struct dm_task *dmt = dm_zalloc(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;
}
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;
dmt->new_uuid = 0;
dmt->secure_data = 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;
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);
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)
{
dm_free(dmt->uuid);
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;
}
#ifdef HAVE_SELINUX
static int _selabel_lookup(const char *path, mode_t mode,
security_context_t *scontext)
{
#ifdef HAVE_SELINUX_LABEL_H
if (!_selabel_handle &&
!(_selabel_handle = selabel_open(SELABEL_CTX_FILE, NULL, 0))) {
log_error("selabel_open failed: %s", strerror(errno));
return 0;
}
if (selabel_lookup(_selabel_handle, scontext, path, mode)) {
log_debug("selabel_lookup failed for %s: %s",
path, strerror(errno));
return 0;
}
#else
if (matchpathcon(path, mode, scontext)) {
log_debug("matchpathcon failed for %s: %s",
path, strerror(errno));
return 0;
}
#endif
return 1;
}
#endif
int dm_prepare_selinux_context(const char *path, mode_t mode)
{
#ifdef HAVE_SELINUX
security_context_t scontext = NULL;
if (is_selinux_enabled() <= 0)
return 1;
if (path) {
if (!_selabel_lookup(path, mode, &scontext))
return_0;
log_debug("Preparing SELinux context for %s to %s.", path, scontext);
}
else
log_debug("Resetting SELinux context to default value.");
if (setfscreatecon(scontext) < 0) {
log_sys_error("setfscreatecon", path);
freecon(scontext);
return 0;
}
freecon(scontext);
#endif
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 (!_selabel_lookup(path, mode, &scontext))
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;
}
void selinux_release(void)
{
#ifdef HAVE_SELINUX_LABEL_H
if (_selabel_handle)
selabel_close(_selabel_handle);
_selabel_handle = NULL;
#endif
}
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;
_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() && dm_udev_get_checking() &&
check_udev)
log_warn("%s not set up by udev: Falling back to direct "
"node creation.", path);
(void) dm_prepare_selinux_context(path, S_IFBLK);
old_mask = umask(0);
if (mknod(path, S_IFBLK | mode, dev) < 0) {
log_error("%s: mknod for %s failed: %s", path, dev_name, strerror(errno));
umask(old_mask);
(void) dm_prepare_selinux_context(NULL, 0);
return 0;
}
umask(old_mask);
(void) dm_prepare_selinux_context(NULL, 0);
if (chown(path, uid, gid) < 0) {
log_sys_error("chown", path);
return 0;
}
log_debug("Created %s", path);
return 1;
}
static int _rm_dev_node(const char *dev_name, int check_udev)
{
char path[PATH_MAX];
struct stat info;
_build_dev_path(path, sizeof(path), dev_name);
if (stat(path, &info) < 0)
return 1;
else if (dm_udev_get_sync_support() && dm_udev_get_checking() &&
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;
_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() && dm_udev_get_checking() &&
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() && dm_udev_get_checking() &&
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,
NUM_NODES
} 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);
default:
; /* NOTREACHED */
}
return 1;
}
static DM_LIST_INIT(_node_ops);
static int _count_node_ops[NUM_NODES];
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 void _del_node_op(struct node_op_parms *nop)
{
_count_node_ops[nop->type]--;
dm_list_del(&nop->list);
dm_free(nop);
}
/* Check if there is other the type of node operation stacked */
static int _other_node_ops(node_op_t type)
{
unsigned i;
for (i = 0; i < NUM_NODES; i++)
if (type != i && _count_node_ops[i])
return 1;
return 0;
}
/* Check if udev is supposed to create nodes */
static int _check_udev(int check_udev)
{
return check_udev && dm_udev_get_sync_support() && dm_udev_get_checking();
}
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;
/*
* Note: check_udev must have valid content
*/
if ((type == NODE_DEL) && _other_node_ops(type))
/*
* Ignore any outstanding operations on the node if deleting it.
*/
dm_list_iterate_safe(noph, nopht, &_node_ops) {
nop = dm_list_item(noph, struct node_op_parms);
if (!strcmp(dev_name, nop->dev_name)) {
_del_node_op(nop);
if (!_other_node_ops(type))
break; /* no other non DEL ops */
}
}
else if ((type == NODE_ADD) && _count_node_ops[NODE_DEL] && _check_udev(check_udev))
/*
* If udev is running ignore previous DEL operation on added node.
* (No other operations for this device then DEL could be stacked here).
*/
dm_list_iterate_safe(noph, nopht, &_node_ops) {
nop = dm_list_item(noph, struct node_op_parms);
if ((nop->type == NODE_DEL) &&
!strcmp(dev_name, nop->dev_name)) {
_del_node_op(nop);
break; /* no other DEL ops */
}
}
else if ((type == NODE_RENAME) && _check_udev(check_udev))
/*
* If udev is running ignore any outstanding operations if renaming it.
*
* Currently RENAME operation happens through 'suspend -> resume'.
* On 'resume' device is added with read_ahead settings, so it is
* safe to remove any stacked ADD, RENAME, READ_AHEAD operation
* There cannot be any DEL operation on the renamed device.
*/
dm_list_iterate_safe(noph, nopht, &_node_ops) {
nop = dm_list_item(noph, struct node_op_parms);
if (!strcmp(old_name, nop->dev_name))
_del_node_op(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);
_count_node_ops[type]++;
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);
_del_node_op(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 (dm_snprintf(_dm_dir, sizeof _dm_dir, "%s%s%s", dev_dir, slash, DM_DIR) < 0) {
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;
}
void dm_udev_set_checking(int checking)
{
}
int dm_udev_get_checking(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)
{
update_devs();
return 1;
}
#else /* UDEV_SYNC_SUPPORT */
static int _check_semaphore_is_supported(void)
{
int maxid;
union semun arg;
struct seminfo seminfo;
arg.__buf = &seminfo;
maxid = semctl(0, 0, SEM_INFO, arg);
if (maxid < 0) {
log_warn("Kernel not configured for semaphores (System V IPC). "
"Not using udev synchronisation code.");
return 0;
}
return 1;
}
static int _check_udev_is_running(void)
{
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;
}
static void _check_udev_sync_requirements_once(void)
{
if (_semaphore_supported < 0)
_semaphore_supported = _check_semaphore_is_supported();
if (_udev_running < 0)
_udev_running = _check_udev_is_running();
}
void dm_udev_set_sync_support(int sync_with_udev)
{
_check_udev_sync_requirements_once();
_sync_with_udev = sync_with_udev;
}
int dm_udev_get_sync_support(void)
{
_check_udev_sync_requirements_once();
return _semaphore_supported && dm_cookie_supported() &&
_udev_running && _sync_with_udev;
}
void dm_udev_set_checking(int checking)
{
if ((_udev_checking = checking))
log_debug("DM udev checking enabled");
else
log_debug("DM udev checking disabled");
}
int dm_udev_get_checking(void)
{
return _udev_checking;
}
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;
union semun sem_arg;
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);
sem_arg.val = 1;
if (semctl(gen_semid, 0, SETVAL, sem_arg) < 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_udev_create_cookie(uint32_t *cookie)
{
int semid;
if (!dm_udev_get_sync_support()) {
*cookie = 0;
return 1;
}
return _udev_notify_sem_create(cookie, &semid);
}
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 "
"type %d with flags 0x%" PRIx16, *cookie, semid, dmt->type, 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;
}
static int _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);
}
int dm_udev_wait(uint32_t cookie)
{
int r = _udev_wait(cookie);
update_devs();
return r;
}
#endif /* UDEV_SYNC_SUPPORT */
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