lfs-book-zh_CN/udev-lfs/83-cdrom-symlinks.rules

# /etc/udev/rules.d/83-cdrom-symlinks.rules: Determine CD drive capability.

ACTION!="add",          GOTO="cd_aliases_generator_end"
SUBSYSTEM!="block",     GOTO="cd_aliases_generator_end"
ENV{GENERATED}=="?*",   GOTO="cd_aliases_generator_end"

# Fail the uevent if the autogenerated rules cannot be saved
ENV{ID_CDROM}=="?*", PROGRAM="/bin/grep -c ' / [^[:space:]]* rw' /proc/mounts", \
  RESULT!="1", RUN+="/bin/false", GOTO="cd_aliases_generator_end"

ENV{ID_CDROM}=="?*", PROGRAM="write_cd_rules", SYMLINK+="%c"

LABEL="cd_aliases_generator_end"