contrib/openresolv/libc.in

   1 #!/bin/sh
   2 # Copyright (c) 2007-2023 Roy Marples
   3 # All rights reserved
   4
   5 # libc subscriber for resolvconf
   6
   7 # Redistribution and use in source and binary forms, with or without
   8 # modification, are permitted provided that the following conditions
   9 # are met:
  10 #     * Redistributions of source code must retain the above copyright
  11 #       notice, this list of conditions and the following disclaimer.
  12 #     * Redistributions in binary form must reproduce the above
  13 #       copyright notice, this list of conditions and the following
  14 #       disclaimer in the documentation and/or other materials provided
  15 #       with the distribution.
  16 #
  17 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  18 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  19 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  20 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  21 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  22 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  23 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  27 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28
  29 SYSCONFDIR=@SYSCONFDIR@
  30 LIBEXECDIR=@LIBEXECDIR@
  31 VARDIR=@VARDIR@
  32 IFACEDIR="$VARDIR/interfaces"
  33 NL="
  34 "
  35
  36 # sed may not be available, and this is faster on small files
  37 key_get_value()
  38 {
  39         key="$1"
  40         shift
  41
  42         if [ $# -eq 0 ]; then
  43                 while read -r line; do
  44                         case "$line" in
  45                         "$key"*) echo "${line##$key}";;
  46                         esac
  47                 done
  48         else
  49                 for x do
  50                         while read -r line; do
  51                                 case "$line" in
  52                                 "$key"*) echo "${line##$key}";;
  53                                 esac
  54                         done < "$x"
  55                 done
  56         fi
  57 }
  58
  59 keys_remove()
  60 {
  61         while read -r line; do
  62                 found=false
  63                 for key do
  64                         case "$line" in
  65                         "$key"*|"#"*|" "*|"     "*|"") found=true;;
  66                         esac
  67                         $found && break
  68                 done
  69                 $found || echo "$line"
  70         done
  71 }
  72
  73 local_nameservers="127.* 0.0.0.0 255.255.255.255 ::1"
  74
  75 # Support original resolvconf configuration layout
  76 # as well as the openresolv config file
  77 if [ -f "$SYSCONFDIR"/resolvconf.conf ]; then
  78         . "$SYSCONFDIR"/resolvconf.conf
  79 elif [ -d "$SYSCONFDIR"/resolvconf ]; then
  80         SYSCONFDIR="$SYSCONFDIR/resolvconf"
  81         base="$SYSCONFDIR/resolv.conf.d/base"
  82         if [ -f "$base" ]; then
  83                 prepend_nameservers="$(key_get_value "nameserver " "$base")"
  84                 domain="$(key_get_value "domain " "$base")"
  85                 prepend_search="$(key_get_value "search " "$base")"
  86                 resolv_conf_options="$(key_get_value "options " "$base")"
  87                 resolv_conf_sortlist="$(key_get_value "sortlist " "$base")"
  88         fi
  89         if [ -f "$SYSCONFDIR"/resolv.conf.d/head ]; then
  90                 resolv_conf_head="$(cat "${SYSCONFDIR}"/resolv.conf.d/head)"
  91         fi
  92         if [ -f "$SYSCONFDIR"/resolv.conf.d/tail ]; then
  93                 resolv_conf_tail="$(cat "$SYSCONFDIR"/resolv.conf.d/tail)"
  94         fi
  95 fi
  96 : ${resolv_conf:=/etc/resolv.conf}
  97 : ${resolv_conf_tmp:="$resolv_conf.$$.openresolv"}
  98 : ${libc_service:=nscd}
  99 : ${list_resolv:=@SBINDIR@/resolvconf -l}
 100 if [ "${resolv_conf_head-x}" = x ] && [ -f "$SYSCONFDIR"/resolv.conf.head ]
 101 then
 102         resolv_conf_head="$(cat "${SYSCONFDIR}"/resolv.conf.head)"
 103 fi
 104 if [ "${resolv_conf_tail-x}" = x ] && [ -f "$SYSCONFDIR"/resolv.conf.tail ]
 105 then
 106         resolv_conf_tail="$(cat "$SYSCONFDIR"/resolv.conf.tail)"
 107 fi
 108
 109 backup=true
 110 signature="# Generated by resolvconf"
 111
 112 uniqify()
 113 {
 114         result=
 115         while [ -n "$1" ]; do
 116                 case " $result " in
 117                 *" $1 "*);;
 118                 *) result="$result $1";;
 119                 esac
 120                 shift
 121         done
 122         echo "${result# *}"
 123 }
 124
 125 case "${resolv_conf_passthrough:-NO}" in
 126 [Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1)
 127         backup=false
 128         newest=
 129         for conf in "$IFACEDIR"/*; do
 130                 if [ -z "$newest" ] || [ "$conf" -nt "$newest" ]; then
 131                         newest="$conf"
 132                 fi
 133         done
 134         [ -z "$newest" ] && exit 0
 135         newconf="$(cat "$newest")$NL"
 136         ;;
 137 /dev/null|[Nn][Uu][Ll][Ll])
 138         : ${resolv_conf_local_only:=NO}
 139         if [ "$local_nameservers" = "127.* 0.0.0.0 255.255.255.255 ::1" ]; then
 140                 local_nameservers=
 141         fi
 142         # Need to overwrite our variables.
 143         eval "$(@SBINDIR@/resolvconf -V)"
 144         ;;
 145
 146 *)
 147         [ -z "$RESOLVCONF" ] && eval "$(@SBINDIR@/resolvconf -v)"
 148         ;;
 149 esac
 150 case "${resolv_conf_passthrough:-NO}" in
 151 [Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1) ;;
 152 *)
 153         : ${domain:=$DOMAIN}
 154         newsearch="$(uniqify $prepend_search $SEARCH $append_search)"
 155         NS="$LOCALNAMESERVERS $NAMESERVERS"
 156         newns=
 157         gotlocal=false
 158         for n in $(uniqify $prepend_nameservers $NS $append_nameservers); do
 159                 add=true
 160                 islocal=false
 161                 for l in $local_nameservers; do
 162                         case "$n" in
 163                         $l) islocal=true; gotlocal=true; break;;
 164                         esac
 165                 done
 166                 if ! $islocal; then
 167                         case "${resolv_conf_local_only:-YES}" in
 168                         [Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1)
 169                                 $gotlocal && add=false;;
 170                         esac
 171                 fi
 172                 $add && newns="$newns $n"
 173         done
 174
 175         # Hold our new resolv.conf in a variable to save on temporary files
 176         newconf="$signature$NL"
 177         if [ -n "$resolv_conf_head" ]; then
 178                 newconf="$newconf$resolv_conf_head$NL"
 179         fi
 180
 181         [ -n "$domain" ] && newconf="${newconf}domain $domain$NL"
 182         if [ -n "$newsearch" ] && [ "$newsearch" != "$domain" ]; then
 183                 newconf="${newconf}search $newsearch$NL"
 184         fi
 185         for n in $newns; do
 186                 newconf="${newconf}nameserver $n$NL"
 187         done
 188
 189         # Now add anything we don't care about such as sortlist and options
 190         stuff="$($list_resolv | keys_remove nameserver domain search)"
 191         if [ -n "$stuff" ]; then
 192                 newconf="$newconf$stuff$NL"
 193         fi
 194
 195         # Append any user defined ones
 196         if [ -n "$resolv_conf_options" ]; then
 197                 newconf="${newconf}options $resolv_conf_options$NL"
 198         fi
 199         if [ -n "$resolv_conf_sortlist" ]; then
 200                 newconf="${newconf}sortlist $resolv_conf_sortlist$NL"
 201         fi
 202
 203         if [ -n "$resolv_conf_tail" ]; then
 204                 newconf="$newconf$resolv_conf_tail$NL"
 205         fi
 206         ;;
 207 esac
 208
 209 # Check if the file has actually changed or not
 210 if [ -e "$resolv_conf" ]; then
 211         [ "$(cat "$resolv_conf")" = "$(printf %s "$newconf")" ] && exit 0
 212 fi
 213
 214 # Change is good.
 215 # If the old file does not have our signature, back it up.
 216 # If the new file just has our signature, restore the backup.
 217 if $backup; then
 218         if [ "$newconf" = "$signature$NL" ]; then
 219                 if [ -e "$resolv_conf.bak" ]; then
 220                         newconf="$(cat "$resolv_conf.bak")$NL"
 221                 fi
 222         elif [ -e "$resolv_conf" ]; then
 223                 read line <"$resolv_conf"
 224                 if [ "$line" != "$signature" ]; then
 225                         cp "$resolv_conf" "$resolv_conf.bak"
 226                 fi
 227         fi
 228 fi
 229
 230 # There are pros and cons for writing directly to resolv.conf
 231 # instead of a temporary file and then moving it over.
 232 # The default is to write to resolv.conf as it has the least
 233 # issues and has been the long standing default behaviour.
 234 case "${resolv_conf_mv:-NO}" in
 235 [Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1)
 236         # Protect against symlink attack, ensure new file does not exist
 237         rm -f "$resolv_conf_tmp"
 238         # Keep original file owner, group and mode
 239         [ -r "$resolv_conf" ] && cp -p "$resolv_conf" "$resolv_conf_tmp"
 240         # Create our resolv.conf now
 241         if (umask 022; printf %s "$newconf" >"$resolv_conf_tmp"); then
 242                 mv "$resolv_conf_tmp" "$resolv_conf"
 243         fi
 244         ;;
 245 *)
 246         (umask 022; printf %s "$newconf" >"$resolv_conf")
 247         ;;
 248 esac
 249
 250 if [ -n "$libc_restart" ]; then
 251         eval $libc_restart
 252 elif [ -n "$RESTARTCMD" ]; then
 253         set -- ${libc_service}
 254         eval "$RESTARTCMD"
 255 else
 256         @SBINDIR@/resolvconf -r ${libc_service}
 257 fi
 258
 259 retval=0
 260 # Notify users of the resolver
 261 for script in "$LIBEXECDIR"/libc.d/*; do
 262         if [ -f "$script" ]; then
 263                 if [ -x "$script" ]; then
 264                         "$script" "$@"
 265                 else
 266                         (. "$script")
 267                 fi
 268                 retval=$(($retval + $?))
 269         fi
 270 done
 271 exit $retval