add readme and sbuild patch

0001-add-pre-realbuild-commands-and-post-realbuild-comman.patch

@@ -0,0 +1,88 @@
+From df094f79a67c0835b0fddd73019b09951ed26987 Mon Sep 17 00:00:00 2001
+From: josch <j.schauer@email.de>
+Date: Wed, 4 Jun 2014 22:57:36 +0200
+Subject: [PATCH] add pre-realbuild-commands and post-realbuild-commands
+
+---
+ lib/Sbuild/Build.pm   | 15 +++++++++++++++
+ lib/Sbuild/Conf.pm    |  2 ++
+ lib/Sbuild/Options.pm | 10 ++++++++++
+ 3 files changed, 27 insertions(+)
+
+diff --git a/lib/Sbuild/Build.pm b/lib/Sbuild/Build.pm
+index a24b575..c8552de 100644
+--- a/lib/Sbuild/Build.pm
++++ b/lib/Sbuild/Build.pm
+@@ -1060,6 +1060,12 @@ sub run_external_commands {
+     } elsif ($stage eq "chroot-setup-commands") {
+ 	$self->log_subsection("Chroot Setup Commands");
+ 	$chroot = 1;
++    } elsif ($stage eq "pre-realbuild-commands") {
++	$self->log_subsection("Pre RealBuild Commands");
++	$chroot = 1;
++    } elsif ($stage eq "post-realbuild-commands") {
++	$self->log_subsection("Post RealBuild Commands");
++	$chroot = 1;
+     } elsif ($stage eq "chroot-cleanup-commands") {
+ 	$self->log_subsection("Chroot Cleanup Commands");
+ 	$chroot = 1;
+@@ -1383,6 +1389,10 @@ sub build {
+ 	return 0;
+     }
+ 
++	$self->run_external_commands("pre-realbuild-commands",
++				     $self->get_conf('LOG_EXTERNAL_COMMAND_OUTPUT'),
++				     $self->get_conf('LOG_EXTERNAL_COMMAND_ERROR'));
++
+     $self->set('Build Start Time', time);
+     $self->set('Build End Time', $self->get('Build Start Time'));
+ 
+@@ -1564,6 +1574,11 @@ sub build {
+     $self->log_sep();
+     $self->log("Build finished at $finish_date\n");
+ 
++
++	$self->run_external_commands("post-realbuild-commands",
++				     $self->get_conf('LOG_EXTERNAL_COMMAND_OUTPUT'),
++				     $self->get_conf('LOG_EXTERNAL_COMMAND_ERROR'));
++
+     my @space_files = ("$dscdir");
+ 
+     $self->log_subsubsection("Finished");
+diff --git a/lib/Sbuild/Conf.pm b/lib/Sbuild/Conf.pm
+index 25ec66d..a396821 100644
+--- a/lib/Sbuild/Conf.pm
++++ b/lib/Sbuild/Conf.pm
+@@ -975,6 +975,8 @@ sub setup ($) {
+ 	    DEFAULT => {
+ 		"pre-build-commands" => [],
+ 		"chroot-setup-commands" => [],
++		"pre-realbuild-commands" => [],
++		"post-realbuild-commands" => [],
+ 		"chroot-cleanup-commands" => [],
+ 		"post-build-commands" => [],
+ 	    },
+diff --git a/lib/Sbuild/Options.pm b/lib/Sbuild/Options.pm
+index 4a232bf..fbca939 100644
+--- a/lib/Sbuild/Options.pm
++++ b/lib/Sbuild/Options.pm
+@@ -267,6 +267,16 @@ sub set_options {
+ 			   push(@{${$self->get_conf('EXTERNAL_COMMANDS')}{"chroot-setup-commands"}},
+ 				\@command);
+ 		       },
++			"pre-realbuild-commands=s" => sub {
++			   my @command = split(/\s+/, $_[1]);
++			   push(@{${$self->get_conf('EXTERNAL_COMMANDS')}{"pre-realbuild-commands"}},
++				\@command);
++		       },
++			"post-realbuild-commands=s" => sub {
++			   my @command = split(/\s+/, $_[1]);
++			   push(@{${$self->get_conf('EXTERNAL_COMMANDS')}{"post-realbuild-commands"}},
++				\@command);
++		       },
+ 			"chroot-cleanup-commands=s" => sub {
+ 			   my @command = split(/\s+/, $_[1]);
+ 			   push(@{${$self->get_conf('EXTERNAL_COMMANDS')}{"chroot-cleanup-commands"}},
+-- 
+1.9.2
+

README.md

@@ -0,0 +1,24 @@
+Use `fatrace` to record all file access during an `sbuild` run and find those
+build dependencies which have their files never needed. You need superuser
+privileges to run this script because of `fatrace`.
+
+Run it like follows. In one terminal execute:
+
+	$ ./findunusedbd.sh
+
+In another run sbuild like this:
+
+	$ sbuild \
+		--chroot-setup-commands='/home/user/path/to/findunusedbd.sh chroot-setup' \
+		--pre-realbuild-commands='/home/user/path/to/findunusedbd.sh pre-realbuild' \
+		--post-realbuild-commands='/home/user/path/to/findunusedbd.sh post-realbuild'
+
+This needs the --pre-realbuild-commands and --post-realbuild-commands to exist
+which can be added to sbuild by applying
+`0001-add-pre-realbuild-commands-and-post-realbuild-comman.patch` to it.
+
+Any unused dependencies can then be found by investigating the file
+`unneededdepends.list`.
+
+Bugs: when investigating which build dependencies are unused, virtual packages
+are not taken into account.