dpkg-shlibdeps: use get_control_path()

Do not hardcode the location of shlibs/symbols files. They are under the
control of dpkg. By using dpkg-query --control-path we ensure that we
always use the correct location.

Sponsored-by: Linaro Limited

debian/changelog

@@ -58,6 +58,8 @@ dpkg (1.16.0) UNRELEASED; urgency=low
     instead of -O2 when building ppc64 packages on Ubuntu. Closes: #612472
   * Add new function get_control_path() to Dpkg::Path, it wraps dpkg-query
     --control-path.
+  * Update dpkg-shlibdeps to be multiarch-ready:
+    - use get_control_path() to find symbols/shlibs files
 
   [ Jonathan Nieder ]
   * Remove support for use of synchronous sync(2), due to its pernicious

man/dpkg-shlibdeps.1

@@ -62,9 +62,9 @@ other binary packages.
 Per-system overriding shared library dependency information.
 \fIarch\fR is the architecture of the current system (obtained by
 .BR "dpkg-architecture -qDEB_HOST_ARCH" ).
-.IP \fIadmindir\fR/info/\fIpackage\fR.symbols
+.IP File returned by dpkg-query --control-path \fIpackage\fR symbols
 Package-provided shared library dependency information.
-Unless overridden, \fIadmindir\fR is /var/lib/dpkg.
+Unless overridden by --admindir, those files are located in /var/lib/dpkg.
 .P 
 While scanning the symbols used by all binaries,
 .B dpkg\-shlibdeps
@@ -96,9 +96,9 @@ Shared library information generated by the current build process that also invo
 They are only used if the library is found in a package's build tree. The
 shlibs file in that build tree takes precedence over shlibs files from
 other binary packages.
-.IP \fIadmindir\fR/info/\fIpackage\fR.shlibs
+.IP File returned by dpkg-query --control-path \fIpackage\fR shlibs
 Package-provided shared library dependency information.
-Unless overridden, \fIadmindir\fR is /var/lib/dpkg.
+Unless overridden by --admindir, those files are located in /var/lib/dpkg.
 .IP /etc/dpkg/shlibs.default
 Per-system default shared library dependency information.
 .P

scripts/dpkg-shlibdeps.pl

@@ -26,7 +26,7 @@ use Dpkg;
 use Dpkg::Gettext;
 use Dpkg::ErrorHandling;
 use Dpkg::Path qw(relative_to_pkg_root guess_pkg_root_dir
-		  check_files_are_the_same);
+		  check_files_are_the_same get_control_path);
 use Dpkg::Version;
 use Dpkg::Shlibs qw(find_library @librarypaths);
 use Dpkg::Shlibs::Objdump;
@@ -91,6 +91,7 @@ foreach (@ARGV) {
 	$admindir = $1;
 	-d $admindir ||
 	    error(_g("administrative directory '%s' does not exist"), $admindir);
+	$ENV{'DPKG_ADMINDIR'} = $admindir;
     } elsif (m/^-d(.*)$/) {
 	$dependencyfield = field_capitalize($1);
 	defined($depstrength{$dependencyfield}) ||
@@ -635,7 +636,8 @@ sub add_shlibs_dep {
 	# Fallback to other shlibs files but it shouldn't be necessary
 	push @shlibs, @pkg_shlibs;
     } else {
-	push @shlibs, "$admindir/info/$pkg.shlibs";
+	my $control_file = get_control_path($pkg, "shlibs");
+	push @shlibs, $control_file if defined $control_file;
     }
     push @shlibs, $shlibsdefault;
     print " Looking up shlibs dependency of $soname provided by '$pkg'\n" if $debug;
@@ -723,8 +725,9 @@ sub find_symbols_file {
 	push @files, @pkg_symbols;
     } else {
 	push @files, "/etc/dpkg/symbols/$pkg.symbols.$host_arch",
-	    "/etc/dpkg/symbols/$pkg.symbols",
-	    "$admindir/info/$pkg.symbols";
+	    "/etc/dpkg/symbols/$pkg.symbols";
+	my $control_file = get_control_path($pkg, "symbols");
+	push @files, $control_file if defined $control_file;
     }
 
     foreach my $file (@files) {