Added udev rules to kernel module build of xloop

The added rules allow udev to properly detect disks and partitions
exposed by the xloop kernel module. A proper detection of disks and
partitions is needed by some command line tools from the util-linux
package.

2 files changed, 62 insertions, 0 deletions

diff --git a/kernel/CMakeLists.txt b/kernel/CMakeLists.txt
index 2dace3f..0e867f6 100644
--- a/kernel/CMakeLists.txt
+++ b/kernel/CMakeLists.txt
@@ -74,3 +74,9 @@ add_kernel_module(xloop_file_fmt_qcow "${KERNEL_DIR}"
 if(${CMAKE_BUILD_TYPE} MATCHES Debug)
     add_subdirectory(tests)
 endif()
+
+# install udev rules for xloop devices exposed by the xloop kernel module
+install(PROGRAMS ${CMAKE_CURRENT_SOURCE_DIR}/udev/50-xloop.rules
+        DESTINATION /lib/udev/rules.d
+        PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
+        COMPONENT main)
diff --git a/kernel/udev/50-xloop.rules b/kernel/udev/50-xloop.rules
new file mode 100644
index 0000000..fac04e0
--- /dev/null
+++ b/kernel/udev/50-xloop.rules
@@ -0,0 +1,56 @@
+# Adapted from /usr/lib/udev/rules.d/60-persistent-storage.rules
+# Only handle /dev/xloop* devices.
+#
+# persistent storage links: /dev/disk/{by-id,by-uuid,by-label,by-path}
+# scheme based on "Linux persistent device names", 2004, Hannes Reinecke <hare@suse.de>
+
+ACTION=="remove", GOTO="xloop_storage_end"
+ENV{UDEV_DISABLE_PERSISTENT_STORAGE_RULES_FLAG}=="1", GOTO="xloop_storage_end"
+
+SUBSYSTEM!="block", GOTO="xloop_storage_end"
+KERNEL!="xloop*", GOTO="xloop_storage_end"
+
+# ignore partitions that span the entire disk
+TEST=="whole_disk", GOTO="xloop_storage_end"
+
+# For partitions import parent disk ID_* information, except ID_FS_*.
+#
+# This is particularly important on media where a filesystem superblock and
+# partition table are found on the same level, e.g. common Linux distro ISO
+# installation media.
+#
+# In the case where a partition device points to the same filesystem that
+# was detected on the parent disk, the ID_FS_* information is already
+# present on the partition devices as well as the parent, so no need to
+# propagate it. In the case where the partition device points to a different
+# filesystem, merging the parent ID_FS_ properties would lead to
+# inconsistencies, so we avoid doing so.
+ENV{DEVTYPE}=="partition", \
+  IMPORT{parent}="ID_[!F]*", IMPORT{parent}="ID_", \
+  IMPORT{parent}="ID_F[!S]*", IMPORT{parent}="ID_F", \
+  IMPORT{parent}="ID_FS[!_]*", IMPORT{parent}="ID_FS"
+
+# by-path
+ENV{DEVTYPE}=="disk", DEVPATH!="*/virtual/*", IMPORT{builtin}="path_id"
+KERNEL!="mmcblk[0-9]boot[0-9]", ENV{DEVTYPE}=="disk", ENV{ID_PATH}=="?*", SYMLINK+="disk/by-path/$env{ID_PATH}"
+ENV{DEVTYPE}=="partition", ENV{ID_PATH}=="?*", SYMLINK+="disk/by-path/$env{ID_PATH}-part%n"
+# compatible links for ATA devices
+KERNEL!="mmcblk[0-9]boot[0-9]", ENV{DEVTYPE}=="disk", ENV{ID_PATH_ATA_COMPAT}=="?*", SYMLINK+="disk/by-path/$env{ID_PATH_ATA_COMPAT}"
+ENV{DEVTYPE}=="partition", ENV{ID_PATH_ATA_COMPAT}=="?*", SYMLINK+="disk/by-path/$env{ID_PATH_ATA_COMPAT}-part%n"
+
+# probe filesystem metadata of disks
+KERNEL!="sr*", IMPORT{builtin}="blkid"
+
+# by-label/by-uuid links (filesystem metadata)
+ENV{ID_FS_USAGE}=="filesystem|other|crypto", ENV{ID_FS_UUID_ENC}=="?*", SYMLINK+="disk/by-uuid/$env{ID_FS_UUID_ENC}"
+ENV{ID_FS_USAGE}=="filesystem|other|crypto", ENV{ID_FS_LABEL_ENC}=="?*", SYMLINK+="disk/by-label/$env{ID_FS_LABEL_ENC}"
+
+# by-id (World Wide Name)
+ENV{DEVTYPE}=="disk", ENV{ID_WWN_WITH_EXTENSION}=="?*", SYMLINK+="disk/by-id/wwn-$env{ID_WWN_WITH_EXTENSION}"
+ENV{DEVTYPE}=="partition", ENV{ID_WWN_WITH_EXTENSION}=="?*", SYMLINK+="disk/by-id/wwn-$env{ID_WWN_WITH_EXTENSION}-part%n"
+
+# by-partlabel/by-partuuid links (partition metadata)
+ENV{ID_PART_ENTRY_UUID}=="?*", SYMLINK+="disk/by-partuuid/$env{ID_PART_ENTRY_UUID}"
+ENV{ID_PART_ENTRY_SCHEME}=="gpt", ENV{ID_PART_ENTRY_NAME}=="?*", SYMLINK+="disk/by-partlabel/$env{ID_PART_ENTRY_NAME}"
+
+LABEL="xloop_storage_end"