scripts for persistent names support

scripts for persistent names support

[Marco d'Itri]

[-- Attachment #1: Type: text/plain, Size: 272 bytes --]

I implemented both the "try again later" and "use a temporary file now"
methods to work around the read-only root problem.
Removing the part of the code you do not need is trivial, and I expect
that everybody will only use the scripts as examples anyway.

-- 
ciao,
Marco

[-- Attachment #2: write_cd_rules --]
[-- Type: text/plain, Size: 1793 bytes --]

#!/bin/sh -e

RULES_FILE="/etc/udev/rules.d/z25_persistent-cd.rules"

. /lib/udev/hotplug.functions

##############################################################################
find_next_available() {
  raw_find_next_available "$(find_all_rules 'SYMLINK+=' $1)"
}

write_rule() {
  local match="$1"
  local link="$2"
  local comment="$3"

  {
  if [ "$PRINT_HEADER" ]; then
    PRINT_HEADER=
    echo "# This file was automatically generated by the $0"
    echo "# program, probably run by the cd-aliases-generator.rules rules file."
    echo "#"
    echo "# You can modify it, as long as you keep each rule on a single line"
    echo "# and set the \$GENERATED variable."
    echo ""
  fi

  [ "$comment" ] && echo "# $comment"
  echo "$match, SYMLINK+=\"$link\", ENV{GENERATED}=\"1\""
  } >> $RULES_FILE
  SYMLINKS="$SYMLINKS $link"
}

##############################################################################
if [ -z "$DEVPATH" ]; then
  echo "Missing \$DEVPATH." >&2
  exit 1
fi
if [ -z "$ID_CDROM" ]; then
  echo "$DEVPATH is not a CD reader." >&2
  exit 1
fi

# Exit if the rules file should not be written yet.
abort_if_run_early

# Prevent concurrent processes from modifying the file at the same time.
lock_rules_file

# Check if the rules file is writeable.
choose_rules_file

link_num=$(find_next_available 'cdrom[0-9]*')

match="ENV{ID_CDROM}==\"?*\", ENV{ID_PATH}==\"$ID_PATH\""

comment="$ID_MODEL ($ID_PATH)"

    write_rule "$match" "cdrom$link_num" "$comment"
[ "$ID_CDROM_CD_R" -o "$ID_CDROM_CD_RW" ] && \
    write_rule "$match" "cdrw$link_num"
[ "$ID_CDROM_DVD" ] && \
    write_rule "$match" "dvd$link_num"
[ "$ID_CDROM_DVD_R" -o "$ID_CDROM_DVD_RW" -o "$ID_CDROM_DVD_RAM" ] && \
    write_rule "$match" "dvdrw$link_num"

unlock_rules_file

echo $SYMLINKS

exit 0


[-- Attachment #3: write_net_rules --]
[-- Type: text/plain, Size: 4544 bytes --]

#!/bin/sh -e
#
# This script is run if the interface (recognized by its MAC address) lacks
# a rule for persistent naming.
#
# If there is already a persistent rule with that interface name then the
# current interface needs to be renamed.
# If the interface needs to be renamed, a NAME=value pair will be printed
# on stdout to allow udev to IMPORT it 
#
# Then a rule for the MAC address and interface name is written.

RULES_FILE='/etc/udev/rules.d/z25_persistent-net.rules'

. /lib/udev/hotplug.functions

##############################################################################
device_description() {
  local bus=$(sysreadlink device/bus)
  bus=${bus##*/}

  if   [ "$bus" = pci ]; then
    local vendor_id=$(sysread device/vendor)
    local device_id=$(sysread device/device)
    echo -n "PCI device ${vendor_id#0x}:${device_id#0x}"
  elif [ "$bus" = usb ]; then
    local device=$(sysreadlink device)
    if [ "$device" -a -e $device/../idVendor ]; then
      local idVendor idProduct
      read idVendor  < $device/../idVendor  || true
      read idProduct < $device/../idProduct || true
      printf 'USB device %x/%x' 0x$idVendor 0x$idProduct
    else
      echo -n "UNKNOWN USB device ($DEVPATH)"
    fi
  elif [ "$bus" = ieee1394 ]; then
    local hostid=$(sysreadlink device/host_id)
    if [ "$hostid" ]; then
      hostid=${hostid##*/}
      echo -n "FireWire host adapter $hostid ($DEVPATH)"
    else
      echo -n "UNKNOWN FireWire device ($DEVPATH)"
    fi
  elif [ "$bus" = xen ]; then
    echo -n "Xen virtual interface"
  elif [ "$bus" ]; then
    echo -n "UNKNOWN $bus device ($DEVPATH)"
  else
    echo -n "UNKNOWN device ($DEVPATH)"
  fi

  local driver=$(sysreadlink device/driver)
  if [ "$driver" ]; then echo -n " (${driver##*/})"; fi
}

##############################################################################
interface_name_taken() {
  local value="$(find_all_rules 'NAME=' $INTERFACE)"
  if [ "$value" ]; then
    return 0
  else
    return 1
  fi
}

find_next_available() {
  raw_find_next_available "$(find_all_rules 'NAME=' "$1")"
}

write_rule() {
  local match="$1"
  local name="$2"
  local comment="$3"

  {
  if [ "$PRINT_HEADER" ]; then
    PRINT_HEADER=
    echo "# This file was automatically generated by the $0"
    echo "# program, probably run by the persistent-net-generator.rules rules file."
    echo "#"
    echo "# You can modify it, as long as you keep each rule on a single line."
  fi

  echo ""
  [ "$comment" ] && echo "# $comment"
  echo "SUBSYSTEM==\"net\", $match, NAME=\"$name\""
  } >> $RULES_FILE
}

write_all_rules() {
  cd /sys/class/net/ || return 0

  for INTERFACE in *; do
    case $INTERFACE in
    eth*|ath*|wlan*|ra*|sta*) ;;
    *) continue ;;
    esac

    INTERFACE="$INTERFACE" DEVPATH="/class/net/$INTERFACE" \
      /lib/udev/write_net_rules || true
  done
}

##############################################################################
# can be used only if $RULES_FILE is empty
if [ "$1" = "all_interfaces" ]; then
  if [ -e $RULES_FILE ]; then
    printf "$RULES_FILE exists, persistent interface names\nnot saved.\n" >&2
    exit 0
  fi

  if [ ! -e /sys/class/net/ ]; then
    echo "/sys/class/net/ is not available, persistent interface names not saved." >&2
    exit 0
  fi

  write_all_rules
  exit 0
fi

if [ -z "$INTERFACE" ]; then
  echo "Missing \$INTERFACE." >&2
  exit 1
fi

if [ "$1" ]; then
  MAC_ADDR="$1"
else
  MAC_ADDR=$(sysread address)
fi

if [ -z "$MAC_ADDR" ]; then
  echo "No MAC address for $INTERFACE." >&2
  exit 1
fi
if [ "$MAC_ADDR" = "00:00:00:00:00:00" ]; then
  echo "NULL MAC address for $INTERFACE." >&2
  exit 1
fi

# Exit if the rules file should not be written yet.
abort_if_run_early

# Prevent concurrent processes from modifying the file at the same time.
lock_rules_file

# Check if the rules file is writeable.
choose_rules_file

# If a rule using the current name already exists then find a new name and
# report it to udev which will rename the interface.
basename=${INTERFACE%%[0-9]*}
if interface_name_taken; then
  INTERFACE="$basename$(find_next_available "$basename[0-9]*")"
  if [ ! -t 1 ]; then
    echo "INTERFACE_NEW=$INTERFACE"
  fi
fi

comment=$(device_description)

# the DRIVERS key is needed to not match bridges and VLAN sub-interfaces
match="DRIVERS==\"?*\", ATTRS{address}==\"$MAC_ADDR\""
if [ $basename = "ath" -o $basename = "wlan" ]; then
  match="$match, ATTRS{type}==\"1\"" # do not match the wifi* interfaces
fi

write_rule "$match" "$INTERFACE" "$comment"

unlock_rules_file

exit 0


[-- Attachment #4: hotplug.functions --]
[-- Type: text/plain, Size: 2561 bytes --]

# vim: syntax=sh

PATH='/sbin:/bin'


# Read a single line from file $1 in the $DEVPATH directory.
# The function must not return an error even if the file does not exist.
sysread() {
  local file="$1"
  [ -e "/sys$DEVPATH/$file" ] || return 0
  local value
  read value < "/sys$DEVPATH/$file" || return 0
  echo "$value"
}

sysreadlink() {
  local file="$1"
  [ -e "/sys$DEVPATH/$file" ] || return 0
  readlink -f /sys$DEVPATH/$file 2> /dev/null || true
}

##############################################################################
# Return true if a directory is writeable.
writeable() {
  if ln -s test-link $1/.is-writeable 2> /dev/null; then
    rm -f $1/.is-writeable
    return 0
  else
    return 1
  fi
}

##############################################################################
# Create a lock file for the current rules file.
lock_rules_file() {
  [ -e /dev/.udev/ ] || return 0

  RULES_LOCK="/dev/.udev/.lock-${RULES_FILE##*/}"

  retry=30
  while ! mkdir $RULES_LOCK 2> /dev/null; do
    if [ $retry -eq 0 ]; then
       echo "Cannot lock $RULES_FILE!" >&2
       exit 2
    fi
    sleep 1
    retry=$(($retry - 1))
  done
}

unlock_rules_file() {
  [ "$RULES_LOCK" ] || return 0
  rmdir $RULES_LOCK || true
}

# Choose the real rules file if it is writeable or a temporary file if not.
# Both files should be checked later when looking for existing rules.
choose_rules_file() {
  local tmp_rules_file="/dev/.udev/tmp-rules--${RULES_FILE##*/}"
  [ -e "$RULES_FILE" -o -e "$tmp_rules_file" ] || PRINT_HEADER=1

  if writeable ${RULES_FILE%/*}; then
    RO_RULES_FILE='/dev/null'
  else
    RO_RULES_FILE=$RULES_FILE
    RULES_FILE=$tmp_rules_file
  fi
}

abort_if_run_early() {
  return # DISABLED

  if ! writeable ${RULES_FILE%/*}; then
    exit 0
  fi
}

##############################################################################
# Return the name of the first free device.
raw_find_next_available() {
  local links="$1"

  local basename=${links%%[ 0-9]*}
  local max=-1
  for name in $links; do
    local num=${name#$basename}
    [ "$num" ] || num=0
    [ $num -gt $max ] && max=$num
  done

  local max=$(($max + 1))
  # "name0" actually is just "name"
  [ $max -eq 0 ] && return
  echo "$max"
}

# Find all rules matching a key (with action) and a pattern.
find_all_rules() {
  local key="$1"
  local linkre="$2"
  local match="$3"

  [ -e $RULES_FILE ] || return

  local search='.*[[:space:],]'"$key"'"\('"$linkre"'\)"[[:space:]]*\(,.*\|\\\|\)$'

  echo $(sed -n -e "${match}s/${search}/\1/p" $RO_RULES_FILE $RULES_FILE)
}


[-- Attachment #5: udev.udev-mtab.init --]
[-- Type: text/plain, Size: 422 bytes --]

#!/bin/sh -e
### BEGIN INIT INFO
# Provides:          udev-mtab
# Required-Start:    udev checkroot
# Required-Stop:     
# Default-Start:     S
# Default-Stop:
### END INIT INFO

PATH="/sbin:/bin"

# copy the rules generated before / was mounted read-write
for file in /dev/.udev/tmp-rules--*; do
  dest=${file##*tmp-rules--}
  [ "$dest" = '*' ] && break
  cat $file >> /etc/udev/rules.d/$dest
  rm -f $file
done

exit 0

[-- Attachment #6: cd-aliases-generator.rules --]
[-- Type: text/plain, Size: 558 bytes --]

# These rules generate rules for the /dev/{cdrom,dvd,...} symlinks and
# write them in /etc/udev/rules.d/z20_persistent-cd.rules.
#
# If you want to configure them manually then just delete the symlink
# pointing to this file.
#
# The default symlink for this file is z75_cd-aliases-generator.rules.

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

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

LABEL="cd_aliases_generator_end"


[-- Attachment #7: persistent-net-generator.rules --]
[-- Type: text/plain, Size: 497 bytes --]

ACTION!="add",				GOTO="persistent_net_generator_end"
SUBSYSTEM!="net",			GOTO="persistent_net_generator_end"

# ignore the interface if a name has already been set
NAME=="?*",				GOTO="persistent_net_generator_end"
# ignore interfaces without a driver link
ENV{DRIVER}!="?*",			GOTO="persistent_net_generator_end"

KERNEL=="eth*|ath*|wlan*|ra*|sta*", \
	IMPORT{program}="write_net_rules $attr{address}"

ENV{INTERFACE_NEW}=="?*", NAME="$env{INTERFACE_NEW}"

LABEL="persistent_net_generator_end"


[-- Attachment #8: Type: text/plain, Size: 373 bytes --]

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[-- Attachment #9: Type: text/plain, Size: 226 bytes --]

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Re: scripts for persistent names support

[Kay Sievers]

On Sat, Sep 02, 2006 at 11:06:53AM +0200, Marco d'Itri wrote:
> I implemented both the "try again later" and "use a temporary file now"
> methods to work around the read-only root problem.
> Removing the part of the code you do not need is trivial, and I expect
> that everybody will only use the scripts as examples anyway.

Very nice. Thanks for doing this.


A few comments:

> RULES_FILE="/etc/udev/rules.d/z25_persistent-cd.rules"
> 
> . /lib/udev/hotplug.functions

Can we name that file udev.functions?


> device_description() {
>   local bus=$(sysreadlink device/bus)
>   bus=${bus##*/}

We should not use the 'device' link. It's only a comment, but it's
a nice information. Can't we read this information with udev rules
and export it as an environment variable or pass it as an argument.


> abort_if_run_early() {
>   return # DISABLED

> # copy the rules generated before / was mounted read-write
> for file in /dev/.udev/tmp-rules--*; do
>   dest=${file##*tmp-rules--}

Can't we check with the rule writing script itself, if there are
already created temporary rules, and if yes, we just copy them over?
That way, the failed-event-replay would just take care of copying for
systems who use the --retry-failed?

> # ignore interfaces without a driver link
> ENV{DRIVER}!="?*", GOTO="persistent_net_generator_end"

Does this work? A network device event should never have the DRIVER
property set, as it belongs to a parent device.

Thanks again,
Kay

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Re: scripts for persistent names support

[Marco d'Itri]

On Sep 03, Kay Sievers <kay.sievers@vrfy.org> wrote:

> > . /lib/udev/hotplug.functions
> Can we name that file udev.functions?
Done.

> > device_description() {
> >   local bus=$(sysreadlink device/bus)
> >   bus=${bus##*/}
> We should not use the 'device' link. It's only a comment, but it's
> a nice information. Can't we read this information with udev rules
> and export it as an environment variable or pass it as an argument.
How? Exporting every attribute which can possibly be used look like a
lot of work.

> Can't we check with the rule writing script itself, if there are
> already created temporary rules, and if yes, we just copy them over?
> That way, the failed-event-replay would just take care of copying for
> systems who use the --retry-failed?
No, because the idea is that these failed events will not be replayed.

> > # ignore interfaces without a driver link
> > ENV{DRIVER}!="?*", GOTO="persistent_net_generator_end"
> Does this work? A network device event should never have the DRIVER
> property set, as it belongs to a parent device.
Indeed it does not work anymore...
Originally it used ENV{PHYSDEVDRIVER}, what should I use now? DRIVERS
does not work either.

-- 
ciao,
Marco

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Re: scripts for persistent names support

[Kay Sievers]

On Sun, Sep 03, 2006 at 12:10:09PM +0200, Marco d'Itri wrote:
> On Sep 03, Kay Sievers <kay.sievers@vrfy.org> wrote:
> 
> > > . /lib/udev/hotplug.functions
> > Can we name that file udev.functions?
> Done.

Thanks.

> > > device_description() {
> > >   local bus=$(sysreadlink device/bus)
> > >   bus=${bus##*/}
> > We should not use the 'device' link. It's only a comment, but it's
> > a nice information. Can't we read this information with udev rules
> > and export it as an environment variable or pass it as an argument.
> How? Exporting every attribute which can possibly be used look like a
> lot of work.

Something like this could work?
  SUBSYSTEMS="pci", ENV{COMMENT}="PCI Device: $attr{vendor}:$attr{product}"
  SUBSYSTEMS="usb", ENV{COMMENT}="USB Device: 0x$attr{idVendor}:0x$attr{idProduct}"
  SUBSYSTEMS="ieee1394", ENV{COMMENT}="Firewire Device: $attr{host_id}"
  SUBSYSTEMS="xen", ENV{COMMENT}="Xen virtual device"

> > Can't we check with the rule writing script itself, if there are
> > already created temporary rules, and if yes, we just copy them over?
> > That way, the failed-event-replay would just take care of copying for
> > systems who use the --retry-failed?
> No, because the idea is that these failed events will not be replayed.

Why not? If the called program looks first if there is already a temp
rule for the device, it will try to make the temp rule a real rule,
that's all.
That way, you would not need a start script to do the work if you
already use the retry-failed, and if you don't use the retry-failed,
it will not hurt anything.
The point is that the same code would just work fine without any changes
in both cases, which is nice.

> > > # ignore interfaces without a driver link
> > > ENV{DRIVER}!="?*", GOTO="persistent_net_generator_end"
> > Does this work? A network device event should never have the DRIVER
> > property set, as it belongs to a parent device.
> Indeed it does not work anymore...
> Originally it used ENV{PHYSDEVDRIVER}, what should I use now? DRIVERS
> does not work either.

DRIVERS="?*", indicates that one of your parents is created by a bus
driver. This should create a rule that only runs for a non-virtual
device.

One other thing, we should not assume that rules files are symlinks in
the comments in the headers. Symlinks break the automatic rule reload
on file changes.

Kay

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