udev-lfs/write_cd_rules

   1 #!/bin/sh -e
   2
   3 # This script is run if an optical drive lacks a rule for persistent naming.
   4 #
   5 # It adds symlinks for optical drives based on the device class determined
   6 # by cdrom_id and used ID_PATH to identify the device.
   7
   8 # (C) 2006 Marco d'Itri <md@Linux.IT>
   9 #
  10 # This program is free software: you can redistribute it and/or modify
  11 # it under the terms of the GNU General Public License as published by
  12 # the Free Software Foundation, either version 2 of the License, or
  13 # (at your option) any later version.
  14
  15 # This program is distributed in the hope that it will be useful,
  16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 # GNU General Public License for more details.
  19
  20 # You should have received a copy of the GNU General Public License
  21 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 # debug, if UDEV_LOG=<debug>
  24 if [ -n "$UDEV_LOG" ]; then
  25         if [ "$UDEV_LOG" -ge 7 ]; then
  26                 set -x
  27         fi
  28 fi
  29
  30 RULES_FILE="/etc/udev/rules.d/70-persistent-cd.rules"
  31
  32 . /lib/udev/rule_generator.functions
  33
  34 find_next_available() {
  35         raw_find_next_available "$(find_all_rules 'SYMLINK\+=' "$1")"
  36 }
  37
  38 write_rule() {
  39         local match="$1"
  40         local link="$2"
  41         local comment="$3"
  42
  43         {
  44         if [ "$PRINT_HEADER" ]; then
  45                 PRINT_HEADER=
  46                 echo "# This file was automatically generated by the $0"
  47                 echo "# program, run by the cd-aliases-generator.rules rules file."
  48                 echo "#"
  49                 echo "# You can modify it, as long as you keep each rule on a single"
  50                 echo "# line, and set the \$GENERATED variable."
  51                 echo ""
  52         fi
  53
  54         [ "$comment" ] && echo "# $comment"
  55         echo "$match, SYMLINK+=\"$link\", ENV{GENERATED}=\"1\""
  56         } >> $RULES_FILE
  57         SYMLINKS="$SYMLINKS $link"
  58 }
  59
  60 if [ -z "$DEVPATH" ]; then
  61         echo "Missing \$DEVPATH." >&2
  62         exit 1
  63 fi
  64 if [ -z "$ID_CDROM" ]; then
  65         echo "$DEVPATH is not a CD reader." >&2
  66         exit 1
  67 fi
  68
  69 if [ "$1" ]; then
  70         METHOD="$1"
  71 else
  72         METHOD='by-path'
  73 fi
  74
  75 case "$METHOD" in
  76         by-path)
  77         if [ -z "$ID_PATH" ]; then
  78                 echo "$DEVPATH not supported by path_id. by-id may work." >&2
  79                 exit 1
  80         fi
  81         RULE="ENV{ID_PATH}==\"$ID_PATH\""
  82         ;;
  83
  84         by-id)
  85         if [ "$ID_SERIAL" ]; then
  86                 RULE="ENV{ID_SERIAL}==\"$ID_SERIAL\""
  87         elif [ "$ID_MODEL" -a "$ID_REVISION" ]; then
  88                 RULE="ENV{ID_MODEL}==\"$ID_MODEL\", ENV{ID_REVISION}==\"$ID_REVISION\""
  89         else
  90                 echo "$DEVPATH not supported by ata_id. by-path may work." >&2
  91                 exit 1
  92         fi
  93         ;;
  94
  95         *)
  96         echo "Invalid argument (must be either by-path or by-id)." >&2
  97         exit 1
  98         ;;
  99 esac
 100
 101 # Prevent concurrent processes from modifying the file at the same time.
 102 lock_rules_file
 103
 104 # Check if the rules file is writeable.
 105 choose_rules_file
 106
 107 link_num=$(find_next_available 'cdrom[0-9]*')
 108
 109 match="SUBSYSTEM==\"block\", ENV{ID_CDROM}==\"?*\", $RULE"
 110
 111 comment="$ID_MODEL ($ID_PATH)"
 112
 113         write_rule "$match" "cdrom$link_num" "$comment"
 114 [ "$ID_CDROM_CD_R" -o "$ID_CDROM_CD_RW" ] && \
 115         write_rule "$match" "cdrw$link_num"
 116 [ "$ID_CDROM_DVD" ] && \
 117         write_rule "$match" "dvd$link_num"
 118 [ "$ID_CDROM_DVD_R" -o "$ID_CDROM_DVD_RW" -o "$ID_CDROM_DVD_RAM" ] && \
 119         write_rule "$match" "dvdrw$link_num"
 120 echo >> $RULES_FILE
 121
 122 unlock_rules_file
 123
 124 echo $SYMLINKS
 125
 126 exit 0