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mirror of git://sourceware.org/git/lvm2.git synced 2024-12-25 01:34:38 +03:00
lvm2/lib/device/dev-mpath.c
Zdenek Kabelac b2db01b530 cov: dev-mpath: check config_wwids_file
Since config_wwids_file is checked for NULL,
test is also before calling _read_wwid_file()
that is directly dereferencing it.
2021-07-28 00:49:28 +02:00

485 lines
12 KiB
C

/*
* Copyright (C) 2011 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* 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 "base/memory/zalloc.h"
#include "lib/misc/lib.h"
#include "lib/activate/activate.h"
#include "lib/commands/toolcontext.h"
#include "lib/device/device_id.h"
#ifdef UDEV_SYNC_SUPPORT
#include <libudev.h>
#include "lib/device/dev-ext-udev-constants.h"
#endif
#include <dirent.h>
#define MPATH_PREFIX "mpath-"
/*
* This hash table keeps track of whether a given dm device
* is a mpath device or not.
*
* If dm-3 is an mpath device, then the constant "2" is stored in
* the hash table with the key of the dm minor number ("3" for dm-3).
* If dm-3 is not an mpath device, then the constant "1" is stored in
* the hash table with the key of the dm minor number.
*/
static struct dm_pool *_hash_mem;
static struct dm_hash_table *_minor_hash_tab;
static struct dm_hash_table *_wwid_hash_tab;
#define MAX_WWID_LINE 512
/*
* do we need to check the multipath.conf blacklist?
*/
static void _read_wwid_file(const char *config_wwids_file)
{
FILE *fp;
char line[MAX_WWID_LINE];
char *wwid, *p;
int count = 0;
if (config_wwids_file[0] != '/') {
log_print("Ignoring unknown multipath_wwids_file.");
return;
}
if (!(fp = fopen(config_wwids_file, "r"))) {
log_debug("multipath wwids file not found");
return;
}
while (fgets(line, sizeof(line), fp)) {
if (line[0] == '#')
continue;
wwid = line;
if (line[0] == '/')
wwid++;
/* skip the initial '3' */
wwid++;
if ((p = strchr(wwid, '/')))
*p = '\0';
(void) dm_hash_insert_binary(_wwid_hash_tab, wwid, strlen(wwid), (void*)1);
count++;
}
if (fclose(fp))
stack;
log_debug("multipath wwids read %d from %s", count, config_wwids_file);
}
int dev_mpath_init(const char *config_wwids_file)
{
struct dm_pool *mem;
struct dm_hash_table *minor_tab;
struct dm_hash_table *wwid_tab;
if (!(mem = dm_pool_create("mpath", 256))) {
log_error("mpath pool creation failed.");
return 0;
}
if (!(minor_tab = dm_hash_create(110))) {
log_error("mpath hash table creation failed.");
dm_pool_destroy(mem);
return 0;
}
_hash_mem = mem;
_minor_hash_tab = minor_tab;
/* multipath_wwids_file="" disables the use of the file */
if (config_wwids_file && !strlen(config_wwids_file)) {
log_debug("multipath wwids file disabled.");
return 1;
}
if (!(wwid_tab = dm_hash_create(110))) {
log_error("mpath hash table creation failed.");
dm_hash_destroy(_minor_hash_tab);
dm_pool_destroy(_hash_mem);
_minor_hash_tab = NULL;
_hash_mem = NULL;
return 0;
}
_wwid_hash_tab = wwid_tab;
if (config_wwids_file)
_read_wwid_file(config_wwids_file);
return 1;
}
void dev_mpath_exit(void)
{
if (_minor_hash_tab)
dm_hash_destroy(_minor_hash_tab);
if (_wwid_hash_tab)
dm_hash_destroy(_wwid_hash_tab);
if (_hash_mem)
dm_pool_destroy(_hash_mem);
_minor_hash_tab = NULL;
_wwid_hash_tab = NULL;
_hash_mem = NULL;
}
/*
* given "/dev/foo" return "foo"
*/
static const char *_get_sysfs_name(struct device *dev)
{
const char *name;
if (!(name = strrchr(dev_name(dev), '/'))) {
log_error("Cannot find '/' in device name.");
return NULL;
}
name++;
if (!*name) {
log_error("Device name is not valid.");
return NULL;
}
return name;
}
/*
* given major:minor
* readlink translates /sys/dev/block/major:minor to /sys/.../foo
* from /sys/.../foo return "foo"
*/
static const char *_get_sysfs_name_by_devt(const char *sysfs_dir, dev_t devno,
char *buf, size_t buf_size)
{
const char *name;
char path[PATH_MAX];
int size;
if (dm_snprintf(path, sizeof(path), "%sdev/block/%d:%d", sysfs_dir,
(int) MAJOR(devno), (int) MINOR(devno)) < 0) {
log_error("Sysfs path string is too long.");
return NULL;
}
if ((size = readlink(path, buf, buf_size - 1)) < 0) {
log_sys_error("readlink", path);
return NULL;
}
buf[size] = '\0';
if (!(name = strrchr(buf, '/'))) {
log_error("Cannot find device name in sysfs path.");
return NULL;
}
name++;
return name;
}
static int _get_sysfs_string(const char *path, char *buffer, int max_size)
{
FILE *fp;
int r = 0;
if (!(fp = fopen(path, "r"))) {
log_sys_error("fopen", path);
return 0;
}
if (!fgets(buffer, max_size, fp))
log_sys_error("fgets", path);
else
r = 1;
if (fclose(fp))
log_sys_error("fclose", path);
return r;
}
static int _get_sysfs_dm_mpath(struct dev_types *dt, const char *sysfs_dir, const char *holder_name)
{
char path[PATH_MAX];
char buffer[128];
if (dm_snprintf(path, sizeof(path), "%sblock/%s/dm/uuid", sysfs_dir, holder_name) < 0) {
log_error("Sysfs path string is too long.");
return 0;
}
buffer[0] = '\0';
if (!_get_sysfs_string(path, buffer, sizeof(buffer)))
return_0;
if (!strncmp(buffer, MPATH_PREFIX, 6))
return 1;
return 0;
}
#ifdef UDEV_SYNC_SUPPORT
static int _dev_is_mpath_component_udev(struct device *dev)
{
const char *value;
struct dev_ext *ext;
/*
* external_device_info_source="udev" enables these udev checks.
* external_device_info_source="none" disables them.
*/
if (!(ext = dev_ext_get(dev)))
return_0;
value = udev_device_get_property_value((struct udev_device *)ext->handle, DEV_EXT_UDEV_BLKID_TYPE);
if (value && !strcmp(value, DEV_EXT_UDEV_BLKID_TYPE_MPATH))
return 1;
value = udev_device_get_property_value((struct udev_device *)ext->handle, DEV_EXT_UDEV_MPATH_DEVICE_PATH);
if (value && !strcmp(value, "1"))
return 1;
return 0;
}
#else
static int _dev_is_mpath_component_udev(struct device *dev)
{
return 0;
}
#endif
static int _dev_is_mpath_component_sysfs(struct cmd_context *cmd, struct device *dev)
{
struct dev_types *dt = cmd->dev_types;
const char *part_name;
const char *name; /* e.g. "sda" for "/dev/sda" */
char link_path[PATH_MAX]; /* some obscure, unpredictable sysfs path */
char holders_path[PATH_MAX]; /* e.g. "/sys/block/sda/holders/" */
char dm_dev_path[PATH_MAX]; /* e.g. "/dev/dm-1" */
char *holder_name; /* e.g. "dm-1" */
const char *sysfs_dir = dm_sysfs_dir();
DIR *dr;
struct dirent *de;
int dev_major = MAJOR(dev->dev);
int dev_minor = MINOR(dev->dev);
int dm_dev_major;
int dm_dev_minor;
struct stat info;
dev_t primary_dev;
int is_mpath_component = 0;
/* multipathing is only known to exist for SCSI or NVME devices */
if (!major_is_scsi_device(dt, dev_major) && !dev_is_nvme(dt, dev))
return 0;
switch (dev_get_primary_dev(dt, dev, &primary_dev)) {
case 2: /* The dev is partition. */
part_name = dev_name(dev); /* name of original dev for log_debug msg */
/* gets "foo" for "/dev/foo" where "/dev/foo" comes from major:minor */
if (!(name = _get_sysfs_name_by_devt(sysfs_dir, primary_dev, link_path, sizeof(link_path))))
return_0;
log_debug_devs("%s: Device is a partition, using primary "
"device %s for mpath component detection",
part_name, name);
break;
case 1: /* The dev is already a primary dev. Just continue with the dev. */
/* gets "foo" for "/dev/foo" */
if (!(name = _get_sysfs_name(dev)))
return_0;
break;
default: /* 0, error. */
log_warn("Failed to get primary device for %d:%d.", dev_major, dev_minor);
return 0;
}
if (dm_snprintf(holders_path, sizeof(holders_path), "%sblock/%s/holders", sysfs_dir, name) < 0) {
log_warn("Sysfs path to check mpath is too long.");
return 0;
}
/* also will filter out partitions */
if (stat(holders_path, &info))
return 0;
if (!S_ISDIR(info.st_mode)) {
log_warn("Path %s is not a directory.", holders_path);
return 0;
}
/*
* If any holder is a dm mpath device, then return 1;
*/
if (!(dr = opendir(holders_path))) {
log_debug("Device %s has no holders dir", dev_name(dev));
return 0;
}
while ((de = readdir(dr))) {
if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
continue;
/*
* holder_name is e.g. "dm-1"
* dm_dev_path is then e.g. "/dev/dm-1"
*/
holder_name = de->d_name;
if (dm_snprintf(dm_dev_path, sizeof(dm_dev_path), "%s/%s", cmd->dev_dir, holder_name) < 0) {
log_warn("dm device path to check mpath is too long.");
continue;
}
/*
* stat "/dev/dm-1" which is the holder of the dev we're checking
* dm_dev_major:dm_dev_minor come from stat("/dev/dm-1")
*/
if (stat(dm_dev_path, &info)) {
log_debug_devs("dev_is_mpath_component %s holder %s stat result %d",
dev_name(dev), dm_dev_path, errno);
continue;
}
dm_dev_major = (int)MAJOR(info.st_rdev);
dm_dev_minor = (int)MINOR(info.st_rdev);
if (dm_dev_major != dt->device_mapper_major) {
log_debug_devs("dev_is_mpath_component %s holder %s %d:%d does not have dm major",
dev_name(dev), dm_dev_path, dm_dev_major, dm_dev_minor);
continue;
}
/*
* A previous call may have checked if dm_dev_minor is mpath and saved
* the result in the hash table. If there's a saved result just use that.
*
* The minor number of "/dev/dm-1" is added to the hash table with
* const value 2 meaning that dm minor 1 (for /dev/dm-1) is a multipath dev
* and const value 1 meaning that dm minor 1 is not a multipath dev.
*/
if (_minor_hash_tab) {
long look = (long) dm_hash_lookup_binary(_minor_hash_tab, &dm_dev_minor, sizeof(dm_dev_minor));
if (look > 0) {
log_debug_devs("dev_is_mpath_component %s holder %s %u:%u already checked as %sbeing mpath.",
dev_name(dev), holder_name, dm_dev_major, dm_dev_minor, (look > 1) ? "" : "not ");
is_mpath_component = (look == 2);
goto out;
}
/* no saved result for dm_dev_minor, so check the uuid for it */
}
/*
* Returns 1 if /sys/block/<holder_name>/dm/uuid indicates that
* <holder_name> is a dm device with dm uuid prefix mpath-.
* When true, <holder_name> will be something like "dm-1".
*/
if (_get_sysfs_dm_mpath(dt, sysfs_dir, holder_name)) {
log_debug_devs("dev_is_mpath_component %s holder %s %u:%u ignore mpath component",
dev_name(dev), holder_name, dm_dev_major, dm_dev_minor);
/* For future checks, save that the dm minor refers to mpath ("2" == is mpath) */
if (_minor_hash_tab)
(void) dm_hash_insert_binary(_minor_hash_tab, &dm_dev_minor, sizeof(dm_dev_minor), (void*)2);
is_mpath_component = 1;
goto out;
}
/* For future checks, save that the dm minor does not refer to mpath ("1" == is not mpath) */
if (_minor_hash_tab)
(void) dm_hash_insert_binary(_minor_hash_tab, &dm_dev_minor, sizeof(dm_dev_minor), (void*)1);
}
out:
if (closedir(dr))
stack;
return is_mpath_component;
}
static int _dev_in_wwid_file(struct cmd_context *cmd, struct device *dev)
{
char sysbuf[PATH_MAX] = { 0 };
char *wwid;
long look;
if (!_wwid_hash_tab)
return 0;
if (!read_sys_block(cmd, dev, "device/wwid", sysbuf, sizeof(sysbuf)))
return 0;
if (!sysbuf[0])
return 0;
/*
* sysfs prints wwid as <typestr>.<value>
* multipath wwid uses '3'<value>
* does "<typestr>." always correspond to "3"?
*/
if (!(wwid = strchr(sysbuf, '.')))
return 0;
/* skip the type and dot, just as '3' was skipped from wwids entry */
wwid++;
look = (long) dm_hash_lookup_binary(_wwid_hash_tab, wwid, strlen(wwid));
if (look) {
log_debug_devs("dev_is_mpath_component %s multipath wwid %s", dev_name(dev), wwid);
return 1;
}
return 0;
}
int dev_is_mpath_component(struct cmd_context *cmd, struct device *dev)
{
if (_dev_is_mpath_component_sysfs(cmd, dev) == 1)
goto found;
if (_dev_in_wwid_file(cmd, dev))
goto found;
if (external_device_info_source() == DEV_EXT_UDEV) {
if (_dev_is_mpath_component_udev(dev) == 1)
goto found;
}
return 0;
found:
return 1;
}