udev-lfs/write_net_rules

   1 #!/bin/sh -e
   2
   3 # This script is run to create persistent network device naming rules
   4 # based on properties of the device.
   5 # If the interface needs to be renamed, INTERFACE_NEW=<name> will be printed
   6 # on stdout to allow udev to IMPORT it.
   7
   8 # variables used to communicate:
   9 #   MATCHADDR             MAC address used for the match
  10 #   MATCHID               bus_id used for the match
  11 #   MATCHDEVID            dev_id used for the match
  12 #   MATCHDRV              driver name used for the match
  13 #   MATCHIFTYPE           interface type match
  14 #   COMMENT               comment to add to the generated rule
  15 #   INTERFACE_NAME        requested name supplied by external tool
  16 #   INTERFACE_NEW         new interface name returned by rule writer
  17
  18 # Copyright (C) 2006 Marco d'Itri <md@Linux.IT>
  19 # Copyright (C) 2007 Kay Sievers <kay.sievers@vrfy.org>
  20 #
  21 # This program is free software: you can redistribute it and/or modify
  22 # it under the terms of the GNU General Public License as published by
  23 # the Free Software Foundation, either version 2 of the License, or
  24 # (at your option) any later version.
  25 #
  26 # This program is distributed in the hope that it will be useful,
  27 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  28 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29 # GNU General Public License for more details.
  30 #
  31 # You should have received a copy of the GNU General Public License
  32 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  33
  34 # debug, if UDEV_LOG=<debug>
  35 if [ -n "$UDEV_LOG" ]; then
  36         if [ "$UDEV_LOG" -ge 7 ]; then
  37                 set -x
  38         fi
  39 fi
  40
  41 RULES_FILE='/etc/udev/rules.d/70-persistent-net.rules'
  42
  43 . /lib/udev/rule_generator.functions
  44
  45 interface_name_taken() {
  46         local value="$(find_all_rules 'NAME=' $INTERFACE)"
  47         if [ "$value" ]; then
  48                 return 0
  49         else
  50                 return 1
  51         fi
  52 }
  53
  54 find_next_available() {
  55         raw_find_next_available "$(find_all_rules 'NAME=' "$1")"
  56 }
  57
  58 write_rule() {
  59         local match="$1"
  60         local name="$2"
  61         local comment="$3"
  62
  63         {
  64         if [ "$PRINT_HEADER" ]; then
  65                 PRINT_HEADER=
  66                 echo "# This file was automatically generated by the $0"
  67                 echo "# program, run by the persistent-net-generator.rules rules file."
  68                 echo "#"
  69                 echo "# You can modify it, as long as you keep each rule on a single"
  70                 echo "# line, and change only the value of the NAME= key."
  71         fi
  72
  73         echo ""
  74         [ "$comment" ] && echo "# $comment"
  75         echo "SUBSYSTEM==\"net\", ACTION==\"add\"$match, NAME=\"$name\""
  76         } >> $RULES_FILE
  77 }
  78
  79 if [ -z "$INTERFACE" ]; then
  80         echo "missing \$INTERFACE" >&2
  81         exit 1
  82 fi
  83
  84 # Prevent concurrent processes from modifying the file at the same time.
  85 lock_rules_file
  86
  87 # Check if the rules file is writeable.
  88 choose_rules_file
  89
  90 # the DRIVERS key is needed to not match bridges and VLAN sub-interfaces
  91 if [ "$MATCHADDR" ]; then
  92         match="$match, DRIVERS==\"?*\", ATTR{address}==\"$MATCHADDR\""
  93 fi
  94
  95 if [ "$MATCHDRV" ]; then
  96         match="$match, DRIVERS==\"$MATCHDRV\""
  97 fi
  98
  99 if [ "$MATCHDEVID" ]; then
 100         match="$match, ATTR{dev_id}==\"$MATCHDEVID\""
 101 fi
 102
 103 if [ "$MATCHID" ]; then
 104         match="$match, KERNELS==\"$MATCHID\""
 105 fi
 106
 107 if [ "$MATCHIFTYPE" ]; then
 108         match="$match, ATTR{type}==\"$MATCHIFTYPE\""
 109 fi
 110
 111 if [ -z "$match" ]; then
 112         echo "missing valid match" >&2
 113         unlock_rules_file
 114         exit 1
 115 fi
 116
 117 basename=${INTERFACE%%[0-9]*}
 118
 119 if [ "$INTERFACE_NAME" ]; then
 120         # external tools may request a custom name
 121         COMMENT="$COMMENT (custom name provided by external tool)"
 122         if [ "$INTERFACE_NAME" != "$INTERFACE" ]; then
 123                 INTERFACE=$INTERFACE_NAME;
 124                 echo "INTERFACE_NEW=$INTERFACE"
 125         fi
 126 else
 127         # if a rule using the current name already exists, find a new name
 128         if interface_name_taken; then
 129                 INTERFACE="$basename$(find_next_available "$basename[0-9]*")"
 130                 # prevent INTERFACE from being "eth" instead of "eth0"
 131                 [ "$INTERFACE" = "${INTERFACE%%[ \[\]0-9]*}" ] && INTERFACE=${INTERFACE}0
 132                 echo "INTERFACE_NEW=$INTERFACE"
 133         fi
 134 fi
 135
 136 write_rule "$match" "$INTERFACE" "$COMMENT"
 137
 138 unlock_rules_file
 139
 140 exit 0