dev-mpath: check uuid with device_get_uuid

lib/device/dev-mpath.c

@@ -18,6 +18,7 @@
 #include "lib/commands/toolcontext.h"
 #include "lib/device/device_id.h"
 #include "lib/datastruct/str_list.h"
+#include "device_mapper/misc/dm-ioctl.h"
 #ifdef UDEV_SYNC_SUPPORT
 #include <libudev.h>
 #include "lib/device/dev-ext-udev-constants.h"
@@ -379,48 +380,6 @@ static const char *_get_sysfs_name_by_devt(const char *sysfs_dir, dev_t devno,
  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)
 {
@@ -462,6 +421,7 @@ static int _dev_is_mpath_component_sysfs(struct cmd_context *cmd, struct device
  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 uuid[DM_UUID_LEN];
  char *holder_name; /* e.g. "dm-1" */
  const char *sysfs_dir = dm_sysfs_dir();
  DIR *dr;
@@ -573,12 +533,10 @@ static int _dev_is_mpath_component_sysfs(struct cmd_context *cmd, struct device
  /* 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)) {
+ /* Check whether holder's UUID uses MPATH prefix */
+ /* TODO: reuse/merge with dev_has_mpath_uuid() as this function also recognizes kpartx partition */
+ if (device_get_uuid(cmd, dm_dev_major, dm_dev_minor, uuid, sizeof(uuid)) &&
+ !strncmp(uuid, MPATH_PREFIX, sizeof(MPATH_PREFIX) - 1)) {
  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);