#!/usr/bin/perl -w
-#
-# Generate symlinks in debian packages, reading debian/links. The
-# file contains pairs of files and symlinks.
+=head1 NAME
+
+dh_link - create symlinks in package build directories
+
+=cut
+
+use strict;
+use File::Find;
use Debian::Debhelper::Dh_Lib;
+
+=head1 SYNOPSIS
+
+B<dh_link> [S<I<debhelper options>>] [B<-A>] [B<-X>I<item>] [S<I<source destination> ...>]
+
+=head1 DESCRIPTION
+
+B<dh_link> is a debhelper program that creates symlinks in package build
+directories.
+
+B<dh_link> accepts a list of pairs of source and destination files. The source
+files are the already existing files that will be symlinked from. The
+destination files are the symlinks that will be created. There B<must> be
+an equal number of source and destination files specified.
+
+Be sure you B<do> specify the full filename to both the source and
+destination files (unlike you would do if you were using something like
+L<ln(1)>).
+
+B<dh_link> will generate symlinks that comply with Debian policy - absolute
+when policy says they should be absolute, and relative links with as short
+a path as possible. It will also create any subdirectories it needs to to put
+the symlinks in.
+
+B<dh_link> also scans the package build tree for existing symlinks which do not
+conform to Debian policy, and corrects them (v4 or later).
+
+=head1 FILES
+
+=over 4
+
+=item debian/I<package>.links
+
+Lists pairs of source and destination files to be symlinked. Each pair
+should be put on its own line, with the source and destination separated by
+whitespace.
+
+=back
+
+=head1 OPTIONS
+
+=over 4
+
+=item B<-A>, B<--all>
+
+Create any links specified by command line parameters in ALL packages
+acted on, not just the first.
+
+=item B<-X>I<item>, B<--exclude=>I<item>
+
+Exclude symlinks that contain I<item> anywhere in their filename from
+being corrected to comply with Debian policy.
+
+=item I<source destination> ...
+
+Create a file named I<destination> as a link to a file named I<source>. Do
+this in the package build directory of the first package acted on.
+(Or in all packages if B<-A> is specified.)
+
+=back
+
+=head1 EXAMPLES
+
+ dh_link usr/share/man/man1/foo.1 usr/share/man/man1/bar.1
+
+Make F<bar.1> be a symlink to F<foo.1>
+
+ dh_link var/lib/foo usr/lib/foo \
+ usr/share/man/man1/foo.1 usr/share/man/man1/bar.1
+
+Make F</usr/lib/foo/> be a link to F</var/lib/foo/>, and F<bar.1> be a symlink to
+the F<foo.1>
+
+=cut
+
+# This expand_path expands all path "." and ".." components, but doesn't
+# resolve symbolic links.
+sub expand_path {
+ my $start = @_ ? shift : '.';
+ my @pathname = split(m:/+:,$start);
+
+ my $entry;
+ my @respath;
+ foreach $entry (@pathname) {
+ if ($entry eq '.' || $entry eq '') {
+ # Do nothing
+ }
+ elsif ($entry eq '..') {
+ if ($#respath == -1) {
+ # Do nothing
+ }
+ else {
+ pop @respath;
+ }
+ }
+ else {
+ push @respath, $entry;
+ }
+ }
+
+ my $result;
+ foreach $entry (@respath) {
+ $result .= '/' . $entry;
+ }
+ if (! defined $result) {
+ $result="/"; # special case
+ }
+ return $result;
+}
+
+
init();
-foreach $PACKAGE (@{$dh{DOPACKAGES}}) {
- $TMP=tmpdir($PACKAGE);
- $file=pkgfile($PACKAGE,"links");
+foreach my $package (@{$dh{DOPACKAGES}}) {
+ my $tmp=tmpdir($package);
+ my $file=pkgfile($package,"links");
- undef @links;
+ my @links;
if ($file) {
@links=filearray($file);
}
error("$file lists a link without a destination.");
}
- if (($PACKAGE eq $dh{FIRSTPACKAGE} || $dh{PARAMS_ALL}) && @ARGV) {
+ if (($package eq $dh{FIRSTPACKAGE} || $dh{PARAMS_ALL}) && @ARGV) {
push @links, @ARGV;
}
error("parameters list a link without a destination.");
}
+ # v4 or later and only if there is a temp dir already
+ if (! compat(3) && -e $tmp) {
+ # Scan for existing links and add them to @links, so they
+ # are recreated policy conformant.
+ find(
+ sub {
+ return unless -l;
+ return if excludefile($_);
+ my $dir=$File::Find::dir;
+ $dir=~s/^\Q$tmp\E//;
+ my $target = readlink($_);
+ if ($target=~/^\//) {
+ push @links, $target;
+ }
+ else {
+ push @links, "$dir/$target";
+ }
+ push @links, "$dir/$_";
+
+ },
+ $tmp);
+ }
+
while (@links) {
- $dest=pop @links;
- $src=pop @links;
+ my $dest=pop @links;
+ my $src=expand_path(pop @links);
- # Relivatize src and dest.
$src=~s:^/::;
$dest=~s:^/::;
+
+ if ($src eq $dest) {
+ warning("skipping link from $src to self");
+ next;
+ }
# Make sure the directory the link will be in exists.
- $basedir=Debian::Debhelper::Dh_Lib::dirname("$TMP/$dest");
+ my $basedir=dirname("$tmp/$dest");
if (! -e $basedir) {
doit("install","-d",$basedir);
}
# Policy says that if the link is all within one toplevel
# directory, it should be relative. If it's between
# top level directories, leave it absolute.
- @src_dirs=split(m:/+:,$src);
- @dest_dirs=split(m:/+:,$dest);
- if ($src_dirs[0] eq $dest_dirs[0]) {
+ my @src_dirs=split(m:/+:,$src);
+ my @dest_dirs=split(m:/+:,$dest);
+ if (@src_dirs > 0 && $src_dirs[0] eq $dest_dirs[0]) {
# Figure out how much of a path $src and $dest
# share in common.
- for ($x=0; $x<$#src_dirs && $src_dirs[$x] eq $dest_dirs[$x]; $x++) {}
+ my $x;
+ for ($x=0; $x < @src_dirs && $src_dirs[$x] eq $dest_dirs[$x]; $x++) {}
# Build up the new src.
$src="";
for (1..$#dest_dirs - $x) {
for ($x .. $#src_dirs) {
$src.=$src_dirs[$_]."/";
}
+ if ($x > $#src_dirs && ! length $src) {
+ $src.="."; # special case
+ }
$src=~s:/$::;
}
else {
# Make sure it's properly absolute.
$src="/$src";
}
-
- doit("ln","-sf",$src,"$TMP/$dest");
+
+ if (-d "$tmp/$dest" && ! -l "$tmp/$dest") {
+ error("link destination $tmp/$dest is a directory");
+ }
+ doit("rm", "-f", "$tmp/$dest");
+ doit("ln","-sf", $src, "$tmp/$dest");
}
}
+
+=head1 SEE ALSO
+
+L<debhelper(7)>
+
+This program is a part of debhelper.
+
+=head1 AUTHOR
+
+Joey Hess <joeyh@debian.org>
+
+=cut