src/dpkg-maintscript-helper.sh

   1 #!/bin/sh
   2 #
   3 # Copyright © 2007, 2011-2015 Guillem Jover <guillem@debian.org>
   4 # Copyright © 2010 Raphaël Hertzog <hertzog@debian.org>
   5 # Copyright © 2008 Joey Hess <joeyh@debian.org>
   6 # Copyright © 2005 Scott James Remnant (original implementation on www.dpkg.org)
   7 #
   8 # This program is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # This program is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  20
  21 # The conffile related functions are inspired by
  22 # https://wiki.debian.org/DpkgConffileHandling
  23
  24 # This script is documented in dpkg-maintscript-helper(1)
  25
  26 ##
  27 ## Functions to remove an obsolete conffile during upgrade
  28 ##
  29 rm_conffile() {
  30   local CONFFILE="$1"
  31   local LASTVERSION="$2"
  32   local PACKAGE="$3"
  33
  34   if [ "$LASTVERSION" = "--" ]; then
  35     LASTVERSION=""
  36     PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
  37   fi
  38   if [ "$PACKAGE" = "--" -o -z "$PACKAGE" ]; then
  39     PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
  40   fi
  41   # Skip remaining parameters up to --
  42   while [ "$1" != "--" -a $# -gt 0 ]; do
  43     shift
  44   done
  45   [ $# -gt 0 ] || badusage "missing arguments after --"
  46   shift
  47
  48   [ -n "$PACKAGE" ] || error "couldn't identify the package"
  49   [ -n "$1" ] || error "maintainer script parameters are missing"
  50   [ -n "$DPKG_MAINTSCRIPT_NAME" ] || \
  51     error "environment variable DPKG_MAINTSCRIPT_NAME is required"
  52   [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] || \
  53     error "environment variable DPKG_MAINTSCRIPT_PACKAGE is required"
  54   [ "${CONFFILE}" != "${CONFFILE#/}" ] || \
  55     error "conffile '$CONFFILE' is not an absolute path"
  56   validate_optional_version "$LASTVERSION"
  57
  58   debug "Executing $0 rm_conffile in $DPKG_MAINTSCRIPT_NAME" \
  59         "of $DPKG_MAINTSCRIPT_PACKAGE"
  60   debug "CONFFILE=$CONFFILE PACKAGE=$PACKAGE" \
  61         "LASTVERSION=$LASTVERSION ACTION=$1 PARAM=$2"
  62   case "$DPKG_MAINTSCRIPT_NAME" in
  63   preinst)
  64     if [ "$1" = "install" -o "$1" = "upgrade" ] && [ -n "$2" ] &&
  65        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
  66       prepare_rm_conffile "$CONFFILE" "$PACKAGE"
  67     fi
  68     ;;
  69   postinst)
  70     if [ "$1" = "configure" ] && [ -n "$2" ] &&
  71        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
  72       finish_rm_conffile "$CONFFILE"
  73     fi
  74     ;;
  75   postrm)
  76     if [ "$1" = "purge" ]; then
  77       rm -f "$DPKG_ROOT$CONFFILE.dpkg-bak" \
  78             "$DPKG_ROOT$CONFFILE.dpkg-remove" \
  79             "$DPKG_ROOT$CONFFILE.dpkg-backup"
  80     fi
  81     if [ "$1" = "abort-install" -o "$1" = "abort-upgrade" ] &&
  82        [ -n "$2" ] &&
  83        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
  84       abort_rm_conffile "$CONFFILE" "$PACKAGE"
  85     fi
  86     ;;
  87   *)
  88     debug "$0 rm_conffile not required in $DPKG_MAINTSCRIPT_NAME"
  89     ;;
  90   esac
  91 }
  92
  93 prepare_rm_conffile() {
  94   local CONFFILE="$1"
  95   local PACKAGE="$2"
  96
  97   [ -e "$DPKG_ROOT$CONFFILE" ] || return 0
  98   ensure_package_owns_file "$PACKAGE" "$CONFFILE" || return 0
  99
 100   local md5sum old_md5sum
 101   md5sum="$(md5sum "$DPKG_ROOT$CONFFILE" | sed -e 's/ .*//')"
 102   old_md5sum="$(dpkg-query -W -f='${Conffiles}' "$PACKAGE" | \
 103     sed -n -e "\\'^ $CONFFILE ' { s/ obsolete$//; s/.* //; p }")"
 104   if [ "$md5sum" != "$old_md5sum" ]; then
 105     mv -f "$DPKG_ROOT$CONFFILE" "$DPKG_ROOT$CONFFILE.dpkg-backup"
 106   else
 107     mv -f "$DPKG_ROOT$CONFFILE" "$DPKG_ROOT$CONFFILE.dpkg-remove"
 108   fi
 109 }
 110
 111 finish_rm_conffile() {
 112   local CONFFILE="$1"
 113
 114   if [ -e "$DPKG_ROOT$CONFFILE.dpkg-backup" ]; then
 115     echo "Obsolete conffile $DPKG_ROOT$CONFFILE has been modified by you."
 116     echo "Saving as $DPKG_ROOT$CONFFILE.dpkg-bak ..."
 117     mv -f "$DPKG_ROOT$CONFFILE.dpkg-backup" "$DPKG_ROOT$CONFFILE.dpkg-bak"
 118   fi
 119   if [ -e "$DPKG_ROOT$CONFFILE.dpkg-remove" ]; then
 120     echo "Removing obsolete conffile $DPKG_ROOT$CONFFILE ..."
 121     rm -f "$DPKG_ROOT$CONFFILE.dpkg-remove"
 122   fi
 123 }
 124
 125 abort_rm_conffile() {
 126   local CONFFILE="$1"
 127   local PACKAGE="$2"
 128
 129   ensure_package_owns_file "$PACKAGE" "$CONFFILE" || return 0
 130
 131   if [ -e "$DPKG_ROOT$CONFFILE.dpkg-remove" ]; then
 132     echo "Reinstalling $DPKG_ROOT$CONFFILE that was moved away"
 133     mv "$DPKG_ROOT$CONFFILE.dpkg-remove" "$DPKG_ROOT$CONFFILE"
 134   fi
 135   if [ -e "$DPKG_ROOT$CONFFILE.dpkg-backup" ]; then
 136     echo "Reinstalling $DPKG_ROOT$CONFFILE that was backed-up"
 137     mv "$DPKG_ROOT$CONFFILE.dpkg-backup" "$DPKG_ROOT$CONFFILE"
 138   fi
 139 }
 140
 141 ##
 142 ## Functions to rename a conffile during upgrade
 143 ##
 144 mv_conffile() {
 145   local OLDCONFFILE="$1"
 146   local NEWCONFFILE="$2"
 147   local LASTVERSION="$3"
 148   local PACKAGE="$4"
 149
 150   if [ "$LASTVERSION" = "--" ]; then
 151     LASTVERSION=""
 152     PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
 153   fi
 154   if [ "$PACKAGE" = "--" -o -z "$PACKAGE" ]; then
 155     PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
 156   fi
 157   # Skip remaining parameters up to --
 158   while [ "$1" != "--" -a $# -gt 0 ]; do
 159     shift
 160   done
 161   [ $# -gt 0 ] || badusage "missing arguments after --"
 162   shift
 163
 164   [ -n "$PACKAGE" ] || error "couldn't identify the package"
 165   [ -n "$1" ] || error "maintainer script parameters are missing"
 166   [ -n "$DPKG_MAINTSCRIPT_NAME" ] || \
 167     error "environment variable DPKG_MAINTSCRIPT_NAME is required"
 168   [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] || \
 169     error "environment variable DPKG_MAINTSCRIPT_PACKAGE is required"
 170   [ "${OLDCONFFILE}" != "${OLDCONFFILE#/}" ] || \
 171     error "old-conffile '$OLDCONFFILE' is not an absolute path"
 172   [ "${NEWCONFFILE}" != "${NEWCONFFILE#/}" ] || \
 173     error "new-conffile '$NEWCONFFILE' is not an absolute path"
 174   validate_optional_version "$LASTVERSION"
 175
 176   debug "Executing $0 mv_conffile in $DPKG_MAINTSCRIPT_NAME" \
 177         "of $DPKG_MAINTSCRIPT_PACKAGE"
 178   debug "CONFFILE=$OLDCONFFILE -> $NEWCONFFILE PACKAGE=$PACKAGE" \
 179         "LASTVERSION=$LASTVERSION ACTION=$1 PARAM=$2"
 180   case "$DPKG_MAINTSCRIPT_NAME" in
 181   preinst)
 182     if [ "$1" = "install" -o "$1" = "upgrade" ] && [ -n "$2" ] &&
 183        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
 184       prepare_mv_conffile "$OLDCONFFILE" "$PACKAGE"
 185     fi
 186     ;;
 187   postinst)
 188     if [ "$1" = "configure" ] && [ -n "$2" ] &&
 189        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
 190       finish_mv_conffile "$OLDCONFFILE" "$NEWCONFFILE" "$PACKAGE"
 191     fi
 192     ;;
 193   postrm)
 194     if [ "$1" = "abort-install" -o "$1" = "abort-upgrade" ] &&
 195        [ -n "$2" ] &&
 196        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
 197       abort_mv_conffile "$OLDCONFFILE" "$PACKAGE"
 198     fi
 199     ;;
 200   *)
 201     debug "$0 mv_conffile not required in $DPKG_MAINTSCRIPT_NAME"
 202     ;;
 203   esac
 204 }
 205
 206 prepare_mv_conffile() {
 207   local CONFFILE="$1"
 208   local PACKAGE="$2"
 209
 210   [ -e "$DPKG_ROOT$CONFFILE" ] || return 0
 211
 212   ensure_package_owns_file "$PACKAGE" "$CONFFILE" || return 0
 213
 214   local md5sum old_md5sum
 215   md5sum="$(md5sum "$DPKG_ROOT$CONFFILE" | sed -e 's/ .*//')"
 216   old_md5sum="$(dpkg-query -W -f='${Conffiles}' "$PACKAGE" | \
 217     sed -n -e "\\'^ $CONFFILE ' { s/ obsolete$//; s/.* //; p }")"
 218   if [ "$md5sum" = "$old_md5sum" ]; then
 219     mv -f "$DPKG_ROOT$CONFFILE" "$DPKG_ROOT$CONFFILE.dpkg-remove"
 220   fi
 221 }
 222
 223 finish_mv_conffile() {
 224   local OLDCONFFILE="$1"
 225   local NEWCONFFILE="$2"
 226   local PACKAGE="$3"
 227
 228   rm -f "$DPKG_ROOT$OLDCONFFILE.dpkg-remove"
 229
 230   [ -e "$DPKG_ROOT$OLDCONFFILE" ] || return 0
 231   ensure_package_owns_file "$PACKAGE" "$OLDCONFFILE" || return 0
 232
 233   echo "Preserving user changes to $DPKG_ROOT$NEWCONFFILE (renamed from $DPKG_ROOT$OLDCONFFILE)..."
 234   if [ -e "$DPKG_ROOT$NEWCONFFILE" ]; then
 235     mv -f "$DPKG_ROOT$NEWCONFFILE" "$DPKG_ROOT$NEWCONFFILE.dpkg-new"
 236   fi
 237   mv -f "$DPKG_ROOT$OLDCONFFILE" "$DPKG_ROOT$NEWCONFFILE"
 238 }
 239
 240 abort_mv_conffile() {
 241   local CONFFILE="$1"
 242   local PACKAGE="$2"
 243
 244   ensure_package_owns_file "$PACKAGE" "$CONFFILE" || return 0
 245
 246   if [ -e "$DPKG_ROOT$CONFFILE.dpkg-remove" ]; then
 247     echo "Reinstalling $DPKG_ROOT$CONFFILE that was moved away"
 248     mv "$DPKG_ROOT$CONFFILE.dpkg-remove" "$DPKG_ROOT$CONFFILE"
 249   fi
 250 }
 251
 252 ##
 253 ## Functions to replace a symlink with a directory
 254 ##
 255 symlink_to_dir() {
 256   local SYMLINK="$1"
 257   local SYMLINK_TARGET="$2"
 258   local LASTVERSION="$3"
 259   local PACKAGE="$4"
 260
 261   if [ "$LASTVERSION" = "--" ]; then
 262     LASTVERSION=""
 263     PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
 264   fi
 265   if [ "$PACKAGE" = "--" -o -z "$PACKAGE" ]; then
 266     PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
 267   fi
 268
 269   # Skip remaining parameters up to --
 270   while [ "$1" != "--" -a $# -gt 0 ]; do
 271     shift
 272   done
 273   [ $# -gt 0 ] || badusage "missing arguments after --"
 274   shift
 275
 276   [ -n "$DPKG_MAINTSCRIPT_NAME" ] || \
 277     error "environment variable DPKG_MAINTSCRIPT_NAME is required"
 278   [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] || \
 279     error "environment variable DPKG_MAINTSCRIPT_PACKAGE is required"
 280   [ -n "$PACKAGE" ] || error "cannot identify the package"
 281   [ -n "$SYMLINK" ] || error "symlink parameter is missing"
 282   [ "${SYMLINK#/}" = "$SYMLINK" ] && \
 283     error "symlink pathname is not an absolute path"
 284   [ "${SYMLINK%/}" = "$SYMLINK" ] || \
 285     error "symlink pathname ends with a slash"
 286   [ -n "$SYMLINK_TARGET" ] || error "original symlink target is missing"
 287   [ -n "$1" ] || error "maintainer script parameters are missing"
 288   validate_optional_version "$LASTVERSION"
 289
 290   debug "Executing $0 symlink_to_dir in $DPKG_MAINTSCRIPT_NAME" \
 291         "of $DPKG_MAINTSCRIPT_PACKAGE"
 292   debug "SYMLINK=$SYMLINK -> $SYMLINK_TARGET PACKAGE=$PACKAGE" \
 293         "LASTVERSION=$LASTVERSION ACTION=$1 PARAM=$2"
 294
 295   case "$DPKG_MAINTSCRIPT_NAME" in
 296   preinst)
 297     if [ "$1" = "install" -o "$1" = "upgrade" ] &&
 298        [ -n "$2" ] && [ -h "$DPKG_ROOT$SYMLINK" ] &&
 299        symlink_match "$SYMLINK" "$SYMLINK_TARGET" &&
 300        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
 301       mv -f "$DPKG_ROOT$SYMLINK" "$DPKG_ROOT${SYMLINK}.dpkg-backup"
 302     fi
 303     ;;
 304   postinst)
 305     # We cannot bail depending on the version, as here we only
 306     # know what was the last configured version, and we might
 307     # have been unpacked, then upgraded with an unpack and thus
 308     # never been configured before.
 309     if [ "$1" = "configure" ] &&
 310        [ -h "$DPKG_ROOT${SYMLINK}.dpkg-backup" ] &&
 311        symlink_match "${SYMLINK}.dpkg-backup" "$SYMLINK_TARGET"
 312     then
 313       rm -f "$DPKG_ROOT${SYMLINK}.dpkg-backup"
 314     fi
 315     ;;
 316   postrm)
 317     if [ "$1" = "purge" ] && [ -h "$DPKG_ROOT${SYMLINK}.dpkg-backup" ]; then
 318       rm -f "$DPKG_ROOT${SYMLINK}.dpkg-backup"
 319     fi
 320     if [ "$1" = "abort-install" -o "$1" = "abort-upgrade" ] &&
 321        [ -n "$2" ] &&
 322        [ ! -e "$DPKG_ROOT$SYMLINK" ] &&
 323        [ -h "$DPKG_ROOT${SYMLINK}.dpkg-backup" ] &&
 324        symlink_match "${SYMLINK}.dpkg-backup" "$SYMLINK_TARGET" &&
 325        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
 326       echo "Restoring backup of $DPKG_ROOT$SYMLINK ..."
 327       mv "$DPKG_ROOT${SYMLINK}.dpkg-backup" "$DPKG_ROOT$SYMLINK"
 328     fi
 329     ;;
 330   *)
 331     debug "$0 symlink_to_dir not required in $DPKG_MAINTSCRIPT_NAME"
 332     ;;
 333   esac
 334 }
 335
 336 ##
 337 ## Functions to replace a directory with a symlink
 338 ##
 339 dir_to_symlink() {
 340   local PATHNAME="${1%/}"
 341   local SYMLINK_TARGET="$2"
 342   local LASTVERSION="$3"
 343   local PACKAGE="$4"
 344
 345   if [ "$LASTVERSION" = "--" ]; then
 346     LASTVERSION=""
 347     PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
 348   fi
 349   if [ "$PACKAGE" = "--" -o -z "$PACKAGE" ]; then
 350     PACKAGE="$DPKG_MAINTSCRIPT_PACKAGE${DPKG_MAINTSCRIPT_ARCH:+:$DPKG_MAINTSCRIPT_ARCH}"
 351   fi
 352
 353   # Skip remaining parameters up to --
 354   while [ "$1" != "--" -a $# -gt 0 ]; do
 355     shift
 356   done
 357   [ $# -gt 0 ] || badusage "missing arguments after --"
 358   shift
 359
 360   [ -n "$DPKG_MAINTSCRIPT_NAME" ] || \
 361     error "environment variable DPKG_MAINTSCRIPT_NAME is required"
 362   [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] || \
 363     error "environment variable DPKG_MAINTSCRIPT_PACKAGE is required"
 364   [ -n "$PACKAGE" ] || error "cannot identify the package"
 365   [ -n "$PATHNAME" ] || error "directory parameter is missing"
 366   [ "${PATHNAME#/}" = "$PATHNAME" ] && \
 367     error "directory parameter is not an absolute path"
 368   [ -n "$SYMLINK_TARGET" ] || error "new symlink target is missing"
 369   [ -n "$1" ] || error "maintainer script parameters are missing"
 370   validate_optional_version "$LASTVERSION"
 371
 372   debug "Executing $0 dir_to_symlink in $DPKG_MAINTSCRIPT_NAME" \
 373         "of $DPKG_MAINTSCRIPT_PACKAGE"
 374   debug "PATHNAME=$PATHNAME SYMLINK_TARGET=$SYMLINK_TARGET" \
 375         "PACKAGE=$PACKAGE LASTVERSION=$LASTVERSION ACTION=$1 PARAM=$2"
 376
 377   case "$DPKG_MAINTSCRIPT_NAME" in
 378   preinst)
 379     if [ "$1" = "install" -o "$1" = "upgrade" ] &&
 380        [ -n "$2" ] &&
 381        [ ! -h "$DPKG_ROOT$PATHNAME" ] &&
 382        [ -d "$DPKG_ROOT$PATHNAME" ] &&
 383        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
 384       prepare_dir_to_symlink "$PACKAGE" "$PATHNAME"
 385     fi
 386     ;;
 387   postinst)
 388     # We cannot bail depending on the version, as here we only
 389     # know what was the last configured version, and we might
 390     # have been unpacked, then upgraded with an unpack and thus
 391     # never been configured before.
 392     if [ "$1" = "configure" ] &&
 393        [ -d "$DPKG_ROOT${PATHNAME}.dpkg-backup" ] &&
 394        [ ! -h "$DPKG_ROOT$PATHNAME" ] &&
 395        [ -d "$DPKG_ROOT$PATHNAME" ] &&
 396        [ -f "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir" ]; then
 397       finish_dir_to_symlink "$PATHNAME" "$SYMLINK_TARGET"
 398     fi
 399     ;;
 400   postrm)
 401     if [ "$1" = "purge" ] &&
 402        [ -d "$DPKG_ROOT${PATHNAME}.dpkg-backup" ]; then
 403       rm -rf "$DPKG_ROOT${PATHNAME}.dpkg-backup"
 404     fi
 405     if [ "$1" = "abort-install" -o "$1" = "abort-upgrade" ] &&
 406        [ -n "$2" ] &&
 407        [ -d "$DPKG_ROOT${PATHNAME}.dpkg-backup" ] &&
 408        [ \( ! -h "$DPKG_ROOT$PATHNAME" -a \
 409             -d "$DPKG_ROOT$PATHNAME" -a \
 410             -f "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir" \) -o \
 411          \( -h "$DPKG_ROOT$PATHNAME" -a \
 412             \( "$(readlink "$DPKG_ROOT$PATHNAME")" = "$SYMLINK_TARGET" -o \
 413                "$(dpkg-realpath "$PATHNAME")" = "$SYMLINK_TARGET" \) \) ] &&
 414        dpkg --compare-versions -- "$2" le-nl "$LASTVERSION"; then
 415       abort_dir_to_symlink "$PATHNAME"
 416     fi
 417     ;;
 418   *)
 419     debug "$0 dir_to_symlink not required in $DPKG_MAINTSCRIPT_NAME"
 420     ;;
 421   esac
 422 }
 423
 424 prepare_dir_to_symlink()
 425 {
 426   local PACKAGE="$1"
 427   local PATHNAME="$2"
 428
 429   local LINE
 430   # If there are conffiles we should not perform the switch.
 431   dpkg-query -W -f='${Conffiles}\n' "$PACKAGE" | while read -r LINE; do
 432     case "$LINE" in
 433     "$PATHNAME"/*)
 434       error "directory '$PATHNAME' contains conffiles," \
 435             "cannot switch to symlink"
 436       ;;
 437     esac
 438   done
 439
 440   # If there are locally created files or files owned by another package
 441   # we should not perform the switch.
 442   export DPKG_MAINTSCRIPT_HELPER_INTERNAL_API="$version"
 443   find "$DPKG_ROOT$PATHNAME" -print0 | \
 444     xargs -0 -n1 "$0" _internal_pkg_must_own_file "$PACKAGE" || \
 445     error "directory '$PATHNAME' contains files not owned by" \
 446           "package $PACKAGE, cannot switch to symlink"
 447   unset DPKG_MAINTSCRIPT_HELPER_INTERNAL_API
 448
 449   # At this point, we know that the directory either contains no files,
 450   # or only non-conffiles owned by the package.
 451   #
 452   # To do the switch we cannot simply replace it with the final symlink
 453   # just yet, because dpkg needs to remove any file present in the old
 454   # package that have disappeared in the new one, and we do not want to
 455   # lose files resolving to the same pathname in the symlink target.
 456   #
 457   # We cannot replace the directory with a staging symlink either,
 458   # because dpkg will update symlinks to their new target.
 459   #
 460   # So we need to create a staging directory, to avoid removing files
 461   # from other packages, and to trap any new files in the directory
 462   # to move them to their correct place later on.
 463   mv -f "$DPKG_ROOT$PATHNAME" "$DPKG_ROOT${PATHNAME}.dpkg-backup"
 464   mkdir "$DPKG_ROOT$PATHNAME"
 465
 466   # Mark it as a staging directory, so that we can track things.
 467   touch "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir"
 468 }
 469
 470 finish_dir_to_symlink()
 471 {
 472   local PATHNAME="$1"
 473   local SYMLINK_TARGET="$2"
 474
 475   # Move the contents of the staging directory to the symlink target,
 476   # as those are all new files installed between this package being
 477   # unpacked and configured.
 478   local ABS_SYMLINK_TARGET
 479   if [ "${SYMLINK_TARGET#/}" = "$SYMLINK_TARGET" ]; then
 480     ABS_SYMLINK_TARGET="$(dirname "$PATHNAME")/$SYMLINK_TARGET"
 481   else
 482     ABS_SYMLINK_TARGET="$SYMLINK_TARGET"
 483   fi
 484   rm "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir"
 485   find "$DPKG_ROOT$PATHNAME" -mindepth 1 -maxdepth 1 -print0 | \
 486     xargs -0 -I% mv -f "%" "$DPKG_ROOT$ABS_SYMLINK_TARGET/"
 487
 488   # Remove the staging directory.
 489   rmdir "$DPKG_ROOT$PATHNAME"
 490
 491   # Do the actual switch.
 492   ln -s "$SYMLINK_TARGET" "$DPKG_ROOT$PATHNAME"
 493
 494   # We are left behind the old files owned by this package in the backup
 495   # directory, just remove it.
 496   rm -rf "$DPKG_ROOT${PATHNAME}.dpkg-backup"
 497 }
 498
 499 abort_dir_to_symlink()
 500 {
 501   local PATHNAME="$1"
 502
 503   echo "Restoring backup of $DPKG_ROOT$PATHNAME ..."
 504   if [ -h "$DPKG_ROOT$PATHNAME" ]; then
 505     rm -f "$DPKG_ROOT$PATHNAME"
 506   else
 507     # The staging directory must be empty, as no other package
 508     # should have been unpacked in between.
 509     rm -f "$DPKG_ROOT$PATHNAME/.dpkg-staging-dir"
 510     rmdir "$DPKG_ROOT$PATHNAME"
 511   fi
 512
 513   mv "$DPKG_ROOT${PATHNAME}.dpkg-backup" "$DPKG_ROOT$PATHNAME"
 514 }
 515
 516 # Common functions
 517 validate_optional_version() {
 518   local VERSION="$1"
 519
 520   if [ -z "$VERSION" ]; then
 521     return
 522   fi
 523
 524   if ! VERSIONCHECK=$(dpkg --validate-version -- "$VERSION" 2>&1); then
 525     error "$VERSIONCHECK"
 526   fi
 527 }
 528
 529 ensure_package_owns_file() {
 530   local PACKAGE="$1"
 531   local FILE="$2"
 532
 533   if ! dpkg-query -L "$PACKAGE" | grep -F -q -x "$FILE"; then
 534     debug "File '$FILE' not owned by package " \
 535           "'$PACKAGE', skipping $command"
 536     return 1
 537   fi
 538   return 0
 539 }
 540
 541 internal_pkg_must_own_file()
 542 {
 543   local PACKAGE="$1"
 544   local FILE="${2##"$DPKG_ROOT"}"
 545
 546   if [ "$DPKG_MAINTSCRIPT_HELPER_INTERNAL_API" != "$version" ]; then
 547     error "internal API used by external command"
 548   fi
 549
 550   if ! ensure_package_owns_file "$PACKAGE" "$FILE"; then
 551     error "file '$FILE' not owned by package '$PACKAGE'"
 552   fi
 553   return 0
 554 }
 555
 556 symlink_match()
 557 {
 558   local SYMLINK="$1"
 559   local SYMLINK_TARGET="$2"
 560
 561   [ "$(readlink "$DPKG_ROOT$SYMLINK")" = "$SYMLINK_TARGET" ] || \
 562   [ "$(dpkg-realpath "$SYMLINK")" = "$SYMLINK_TARGET" ]
 563 }
 564
 565 usage() {
 566   cat <<END
 567 Usage: $PROGNAME <command> <parameter>... -- <maintainer-script-parameter>...
 568
 569 Commands:
 570   supports <command>
 571         Returns 0 (success) if the given command is supported, 1 otherwise.
 572   rm_conffile <conffile> [<last-version> [<package>]]
 573         Remove obsolete conffile. Must be called in preinst, postinst and
 574         postrm.
 575   mv_conffile <old-conf> <new-conf> [<last-version> [<package>]]
 576         Rename a conffile. Must be called in preinst, postinst and postrm.
 577   symlink_to_dir <pathname> <old-symlink-target> [<last-version> [<package>]]
 578         Replace a symlink with a directory. Must be called in preinst,
 579         postinst and postrm.
 580   dir_to_symlink <pathname> <new-symlink-target> [<last-version> [<package>]]
 581         Replace a directory with a symlink. Must be called in preinst,
 582         postinst and postrm.
 583   help
 584   -?, --help
 585         Show this help message.
 586       --version
 587         Show the version.
 588 END
 589 }
 590
 591 # Main code
 592 set -e
 593
 594 PROGNAME=$(basename "$0")
 595 version="unknown"
 596 DPKG_ROOT=${DPKG_ROOT:+$(realpath "$DPKG_ROOT")}
 597 # Remove default root dir.
 598 if [ "$DPKG_ROOT" = "/" ]; then
 599   DPKG_ROOT=""
 600 fi
 601 export DPKG_ROOT
 602
 603 PKGDATADIR_DEFAULT=src
 604 PKGDATADIR="${DPKG_DATADIR:-$PKGDATADIR_DEFAULT}"
 605
 606 # shellcheck source=src/sh/dpkg-error.sh
 607 . "$PKGDATADIR/sh/dpkg-error.sh"
 608
 609 setup_colors
 610
 611 command="$1"
 612 [ $# -gt 0 ] || badusage "missing command"
 613 shift
 614
 615 case "$command" in
 616 supports)
 617   case "$1" in
 618   rm_conffile|mv_conffile|symlink_to_dir|dir_to_symlink)
 619     code=0
 620     ;;
 621   *)
 622     code=1
 623     ;;
 624   esac
 625   if [ -z "$DPKG_MAINTSCRIPT_NAME" ]; then
 626     warning "environment variable DPKG_MAINTSCRIPT_NAME missing"
 627     code=1
 628   fi
 629   if [ -z "$DPKG_MAINTSCRIPT_PACKAGE" ]; then
 630     warning "environment variable DPKG_MAINTSCRIPT_PACKAGE missing"
 631     code=1
 632   fi
 633   exit $code
 634   ;;
 635 rm_conffile)
 636   rm_conffile "$@"
 637   ;;
 638 mv_conffile)
 639   mv_conffile "$@"
 640   ;;
 641 symlink_to_dir)
 642   symlink_to_dir "$@"
 643   ;;
 644 dir_to_symlink)
 645   dir_to_symlink "$@"
 646   ;;
 647 _internal_pkg_must_own_file)
 648   # This is an internal command, must not be used outside this program.
 649   internal_pkg_must_own_file "$@"
 650   ;;
 651 --help|help|-?)
 652   usage
 653   ;;
 654 --version)
 655   cat <<END
 656 Debian $PROGNAME version $version.
 657
 658 This is free software; see the GNU General Public License version 2 or
 659 later for copying conditions. There is NO warranty.
 660 END
 661   ;;
 662 *)
 663   badusage "command $command is unknown
 664 Hint: upgrading dpkg to a newer version might help."
 665 esac
 666
 667 exit 0