diff --git a/repos/libports/Makefile b/repos/libports/Makefile
index f1222b844..ba10c4fab 100644
--- a/repos/libports/Makefile
+++ b/repos/libports/Makefile
@@ -1,84 +1 @@
-#
-# \brief  Download and unpack upstream library source codes
-# \author Norman Feske
-# \date   2009-10-16
-#
-
-#
-# Print help information by default
-#
-help::
-
-VERBOSE     ?= @
-ECHO         = @echo
-DOWNLOAD_DIR = download
-CONTRIB_DIR  = contrib
-GNU_FIND     = find
-SHELL        = bash
-SIGVERIFIER  = $(CURDIR)/../../tool/download_sigver
-HASHVERIFIER = $(CURDIR)/../../tool/download_hashver
-
-#
-# Create download and contrib directory so that '<port>.mk' files
-# do not need to care for them.
-#
-prepare: $(DOWNLOAD_DIR) $(CONTRIB_DIR)
-
-#
-# Utility to check if a tool is installed
-#
-check_tool = $(if $(shell which $(1)),,$(error Need to have '$(1)' installed.))
-
-$(call check_tool,wget)
-$(call check_tool,patch)
-$(call check_tool,gpg)
-$(call check_tool,md5sum)
-$(call check_tool,sha1sum)
-$(call check_tool,sha256sum)
-
-#
-# Include information about available ports
-#
-# Each '<port>.mk' file in the 'ports/' directory extends the following
-# variables:
-#
-# PORTS     - list names of the available ports, e.g., 'freetype-2.3.9'
-# GEN_DIRS  - list of automatically generated directories
-# GEN_FILES - list of automatically generated files
-#
-# Furthermore, each '<port>.mk' file extends the 'prepare' rule for
-# downloading and unpacking the corresponding upstream sources.
-#
-PKG ?= $(patsubst ports/%.mk,%,$(wildcard ports/*.mk))
-include $(addprefix ports/,$(addsuffix .mk,$(PKG)))
-
-help::
-	$(ECHO)
-	$(ECHO) "Download and unpack upstream source codes:"
-	@for i in $(PORTS); do echo "  $$i"; done
-	$(ECHO)
-	$(ECHO) "Downloads will be placed into the '$(DOWNLOAD_DIR)/' directory."
-	$(ECHO) "Source codes will be unpacked in the '$(CONTRIB_DIR)/' directory."
-	$(ECHO)
-	$(ECHO) "--- available commands ---"
-	$(ECHO) "prepare  - download and unpack upstream source codes"
-	$(ECHO) "clean    - remove upstream source codes"
-	$(ECHO) "cleanall - remove upstream source codes and downloads"
-	$(ECHO)
-	$(ECHO) "--- available arguments ---"
-	$(ECHO) "PKG=<package-list>  - prepare only the specified packages,"
-	$(ECHO) "                      each package specified w/o version number"
-
-prepare: $(addprefix prepare-,$(PKG))
-
-$(DOWNLOAD_DIR) $(CONTRIB_DIR):
-	$(VERBOSE)mkdir -p $@
-
-clean: $(addprefix clean-,$(PKG))
-	$(VERBOSE)if [ -d $(CONTRIB_DIR) ]; then \
-                 $(GNU_FIND) $(CONTRIB_DIR) -depth -type d -empty -delete; fi
-
-cleanall: clean
-	$(VERBOSE)rm -rf $(DOWNLOAD_DIR)
-
-.NOTPARALLEL:
+include ../../tool/prepare.mk
diff --git a/repos/ports/Makefile b/repos/ports/Makefile
index 0f36cf2d5..ba10c4fab 100644
--- a/repos/ports/Makefile
+++ b/repos/ports/Makefile
@@ -1,88 +1 @@
-#
-# \brief  Download and unpack upstream library source codes
-# \author Norman Feske
-# \date   2009-10-16
-#
-
-#
-# Print help information by default
-#
-help::
-
-VERBOSE     ?= @
-ECHO         = @echo
-DOWNLOAD_DIR = download
-CONTRIB_DIR  = contrib
-GNU_FIND     = find
-SHELL        = bash
-SIGVERIFIER  = $(CURDIR)/../../tool/download_sigver
-HASHVERIFIER = $(CURDIR)/../../tool/download_hashver
-
-#
-# Create download and contrib directory so that '<port>.mk' files
-# do not need to care for them.
-#
-prepare:: $(DOWNLOAD_DIR) $(CONTRIB_DIR)
-
-#
-# Utility to check if a tool is installed
-#
-check_tool = $(if $(shell which $(1)),,$(error Need to have '$(1)' installed.))
-
-$(call check_tool,wget)
-$(call check_tool,patch)
-$(call check_tool,gpg)
-$(call check_tool,md5sum)
-$(call check_tool,sha1sum)
-$(call check_tool,sha256sum)
-
-#
-# Include information about available ports
-#
-# Each '<port>.mk' file in the 'ports/' directory extends the following
-# variables:
-#
-# PORTS     - list names of the available ports, e.g., 'freetype-2.3.9'
-# GEN_DIRS  - list of automatically generated directories
-# GEN_FILES - list of automatically generated files
-#
-# Furthermore, each '<port>.mk' file extends the 'prepare' rule for
-# downloading and unpacking the corresponding upstream sources.
-#
-PKG ?= *
-include $(addprefix ports/,$(addsuffix .mk,$(PKG)))
-
-help::
-	$(ECHO) ""
-	$(ECHO) "Download and unpack upstream source codes:"
-	@for i in $(PORTS); do echo "  $$i"; done
-	$(ECHO) ""
-	$(ECHO) "Downloads will be placed into the '$(DOWNLOAD_DIR)/' directory."
-	$(ECHO) "Source codes will be unpacked in the '$(CONTRIB_DIR)/' directory."
-	$(ECHO) ""
-	$(ECHO) "--- available commands ---"
-	$(ECHO) "prepare  - download and unpack upstream source codes"
-	$(ECHO) "clean    - remove upstream source codes"
-	$(ECHO) "cleanall - remove upstream source codes and downloads"
-	$(ECHO) ""
-	$(ECHO) "--- available arguments ---"
-	$(ECHO) "PKG=<package-list>  - prepare only the specified packages,"
-	$(ECHO) "                      each package specified w/o version number"
-
-#
-# Remove download and contrib directories if empty
-#
-prepare::
-	$(VERBOSE)$(GNU_FIND) $(DOWNLOAD_DIR) -depth -type d -empty -delete
-	$(VERBOSE)$(GNU_FIND) $(CONTRIB_DIR)  -depth -type d -empty -delete
-
-$(DOWNLOAD_DIR) $(CONTRIB_DIR):
-	$(VERBOSE)mkdir -p $@
-
-clean::
-	$(VERBOSE)rm -rf $(CONTRIB_DIR)
-
-cleanall: clean
-	$(VERBOSE)rm -rf $(DOWNLOAD_DIR)
-
-.NOTPARALLEL:
+include ../../tool/prepare.mk
diff --git a/repos/ports/ports/arora.mk b/repos/ports/ports/arora.mk
index f117d4ee1..c65d3e7c1 100644
--- a/repos/ports/ports/arora.mk
+++ b/repos/ports/ports/arora.mk
@@ -7,7 +7,7 @@ ARORA_URL = http://arora.googlecode.com/files/$(ARORA_TGZ)
 #
 PORTS += $(ARORA)
 
-prepare:: $(CONTRIB_DIR)/$(ARORA)
+prepare-arora: $(CONTRIB_DIR)/$(ARORA)
 
 PATCHES_DIR = src/app/arora/patches
 
@@ -21,3 +21,6 @@ $(CONTRIB_DIR)/$(ARORA): $(DOWNLOAD_DIR)/$(ARORA_TGZ)
 	$(VERBOSE)tar xfz $< -C $(CONTRIB_DIR) && touch $@
 	$(VERBOSE)for p in $(shell cat $(PATCHES_DIR)/series); do \
 		patch -d $@ -p1 -i ../../$(PATCHES_DIR)/$$p; done;
+
+clean-arora:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(ARORA)
diff --git a/repos/ports/ports/bash.mk b/repos/ports/ports/bash.mk
index 6cf8fa830..4e886bdfb 100644
--- a/repos/ports/ports/bash.mk
+++ b/repos/ports/ports/bash.mk
@@ -11,7 +11,7 @@ BASH_KEY      = GNU
 #
 PORTS += $(BASH)
 
-prepare:: $(CONTRIB_DIR)/$(BASH)
+prepare-bash: $(CONTRIB_DIR)/$(BASH)
 
 #
 # Port-specific local rules
@@ -32,3 +32,5 @@ $(CONTRIB_DIR)/$(BASH): $(DOWNLOAD_DIR)/$(BASH_TGZ).verified
 	$(VERBOSE)patch -d $(CONTRIB_DIR)/$(BASH) -N -p1 < src/noux-pkg/bash/build.patch
 	$(VERBOSE)patch -d $(CONTRIB_DIR)/$(BASH) -N -p1 < src/noux-pkg/bash/check_dev_tty.patch
 
+clean-bash:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(BASH)
diff --git a/repos/ports/ports/binutils.mk b/repos/ports/ports/binutils.mk
index 1448333dc..ffc89fb25 100644
--- a/repos/ports/ports/binutils.mk
+++ b/repos/ports/ports/binutils.mk
@@ -11,7 +11,7 @@ BINUTILS_KEY      = GNU
 #
 PORTS += $(BINUTILS)
 
-prepare:: $(CONTRIB_DIR)/$(BINUTILS)
+prepare-binutils: $(CONTRIB_DIR)/$(BINUTILS)
 
 #
 # Port-specific local rules
@@ -30,3 +30,6 @@ $(DOWNLOAD_DIR)/$(BINUTILS_TBZ2).verified: $(DOWNLOAD_DIR)/$(BINUTILS_TBZ2) \
 $(CONTRIB_DIR)/$(BINUTILS): $(DOWNLOAD_DIR)/$(BINUTILS_TBZ2).verified
 	$(VERBOSE)tar xfj $(<:.verified=) -C $(CONTRIB_DIR) && touch $@
 	$(VERBOSE)patch -d $(CONTRIB_DIR)/$(BINUTILS) -N -p1 < src/noux-pkg/binutils/build.patch
+
+clean-binutils:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(BINUTILS)
diff --git a/repos/ports/ports/coreutils.mk b/repos/ports/ports/coreutils.mk
index 74d694273..f57af88a9 100644
--- a/repos/ports/ports/coreutils.mk
+++ b/repos/ports/ports/coreutils.mk
@@ -11,7 +11,7 @@ COREUTILS_KEY      = GNU
 #
 PORTS += $(COREUTILS)
 
-prepare:: $(CONTRIB_DIR)/$(COREUTILS)
+prepare-coreutils: $(CONTRIB_DIR)/$(COREUTILS)
 
 #
 # Port-specific local rules
@@ -30,3 +30,5 @@ $(DOWNLOAD_DIR)/$(COREUTILS_TGZ).verified: $(DOWNLOAD_DIR)/$(COREUTILS_TGZ) \
 $(CONTRIB_DIR)/$(COREUTILS): $(DOWNLOAD_DIR)/$(COREUTILS_TGZ)
 	$(VERBOSE)tar xfz $(<:.verified=) -C $(CONTRIB_DIR) && touch $@
 
+clean-coreutils:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(COREUTILS)
diff --git a/repos/ports/ports/dash.mk b/repos/ports/ports/dash.mk
index 285bd26bb..55f1e8281 100644
--- a/repos/ports/ports/dash.mk
+++ b/repos/ports/ports/dash.mk
@@ -7,7 +7,7 @@ DASH_URL = http://gondor.apana.org.au/~herbert/dash/files/$(DASH_TGZ)
 #
 PORTS += $(DASH)
 
-prepare:: $(CONTRIB_DIR)/$(DASH)
+prepare-dash: $(CONTRIB_DIR)/$(DASH)
 
 #
 # Port-specific local rules
@@ -19,3 +19,6 @@ $(CONTRIB_DIR)/$(DASH): $(DOWNLOAD_DIR)/$(DASH_TGZ)
 	$(VERBOSE)tar xfz $< -C $(CONTRIB_DIR) && touch $@
 	$(VERBOSE)patch -N -p0 < src/noux-pkg/dash/build.patch
 
+clean-dash:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(DASH)
+
diff --git a/repos/ports/ports/dosbox.mk b/repos/ports/ports/dosbox.mk
index 98ce5c611..38b40edb7 100644
--- a/repos/ports/ports/dosbox.mk
+++ b/repos/ports/ports/dosbox.mk
@@ -7,7 +7,7 @@ DOSBOX_SVN_URL = http://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk
 #
 PORTS += $(DOSBOX)
 
-prepare:: $(CONTRIB_DIR)/$(DOSBOX)
+prepare-dosbox: $(CONTRIB_DIR)/$(DOSBOX)
 
 #
 # Port-specific local rules
@@ -17,3 +17,6 @@ $(CONTRIB_DIR)/$(DOSBOX):
 	$(VERBOSE)svn export $(DOSBOX_SVN_URL)@$(DOSBOX_REV) $@
 	$(VERBOSE)for i in src/app/dosbox/patches/*.patch; do \
 		patch -N -p0 < $$i; done || true
+
+clean-dosbox:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(DOSBOX)
diff --git a/repos/ports/ports/e2fsprogs.mk b/repos/ports/ports/e2fsprogs.mk
index db637e465..db11a0222 100644
--- a/repos/ports/ports/e2fsprogs.mk
+++ b/repos/ports/ports/e2fsprogs.mk
@@ -10,7 +10,7 @@ $(call check_tool,git)
 #
 PORTS += $(E2FSPROGS)
 
-prepare:: $(CONTRIB_DIR)/$(E2FSPROGS)
+prepare-e2fsprogs: $(CONTRIB_DIR)/$(E2FSPROGS)
 
 #
 # Port-specific local rules
@@ -21,3 +21,6 @@ $(CONTRIB_DIR)/$(E2FSPROGS):
 	git checkout -b $(E2FSPROGS_BRANCH) $(E2FSPROGS_BRANCH)
 	$(VERBOSE)for i in src/noux-pkg/e2fsprogs/patches/*.patch; do \
 		patch -d $(CONTRIB_DIR)/$(E2FSPROGS) -N -p1 < $$i; done || true
+
+clean-e2fsprogs:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(E2FSPROGS)
diff --git a/repos/ports/ports/etc.mk b/repos/ports/ports/etc.mk
index 0fa08fbc9..bb7e77865 100644
--- a/repos/ports/ports/etc.mk
+++ b/repos/ports/ports/etc.mk
@@ -19,7 +19,7 @@ $(CONTRIB_DIR)/$(ETC):
 	$(ECHO) "checking out 'etc' to '$@'"
 	$(VERBOSE)svn export $(ETC_SVN_BASE)/etc $@
 
-prepare:: $(CONTRIB_DIR)/$(ETC)
+prepare-etc: $(CONTRIB_DIR)/$(ETC)
 
 clean-etc:
 	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(ETC)
diff --git a/repos/ports/ports/findutils.mk b/repos/ports/ports/findutils.mk
index c156661e6..fb7c6d8c9 100644
--- a/repos/ports/ports/findutils.mk
+++ b/repos/ports/ports/findutils.mk
@@ -11,7 +11,7 @@ FINDUTILS_KEY      = GNU
 #
 PORTS += $(FINDUTILS)
 
-prepare:: $(CONTRIB_DIR)/$(FINDUTILS)
+prepare-findutils: $(CONTRIB_DIR)/$(FINDUTILS)
 
 #
 # Port-specific local rules
@@ -30,3 +30,6 @@ $(DOWNLOAD_DIR)/$(FINDUTILS_TGZ).verified: $(DOWNLOAD_DIR)/$(FINDUTILS_TGZ) \
 $(CONTRIB_DIR)/$(FINDUTILS): $(DOWNLOAD_DIR)/$(FINDUTILS_TGZ).verified
 	$(VERBOSE)tar xfz $(<:.verified=) -C $(CONTRIB_DIR) && touch $@
 	$(VERBOSE)patch -d $(CONTRIB_DIR)/$(FINDUTILS) -N -p1 < src/noux-pkg/findutils/build.patch
+
+clean-findutils:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(FINDUTILS)
diff --git a/repos/ports/ports/gcc.mk b/repos/ports/ports/gcc.mk
index 015cdf79b..8a82a88e6 100644
--- a/repos/ports/ports/gcc.mk
+++ b/repos/ports/ports/gcc.mk
@@ -10,7 +10,7 @@ GCC_KEY     = GNU
 #
 PORTS += $(GCC)
 
-prepare:: $(CONTRIB_DIR)/$(GCC)/configure
+prepare-gcc: $(CONTRIB_DIR)/$(GCC)/configure
 
 #
 # Port-specific local rules
@@ -57,3 +57,6 @@ $(CONTRIB_DIR)/$(GCC)/configure:: $(CONTRIB_DIR)/$(GCC)
 	@#
 	$(VERBOSE)patch -d $(CONTRIB_DIR)/$(GCC) -N -p1 < src/noux-pkg/gcc/build.patch
 	$(VERBOSE)patch -d $(CONTRIB_DIR)/$(GCC) -N -p1 < src/noux-pkg/gcc/build_with_makeinfo_5.patch
+
+clean-gcc:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(GCC)
diff --git a/repos/ports/ports/gdb.mk b/repos/ports/ports/gdb.mk
index e9fcc71ba..02a1f6519 100644
--- a/repos/ports/ports/gdb.mk
+++ b/repos/ports/ports/gdb.mk
@@ -45,7 +45,7 @@ GDB_CONTENT := gdb/regformats/regdat.sh \
 #
 PORTS += $(GDB)
 
-prepare:: clean-gdb $(CONTRIB_DIR)/$(GDB)/configure generated_files
+prepare-gdb: clean-gdb $(CONTRIB_DIR)/$(GDB)/configure generated_files
 
 clean-gdb:
 	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(GDB)
diff --git a/repos/ports/ports/grep.mk b/repos/ports/ports/grep.mk
index 26132ace0..183e43b48 100644
--- a/repos/ports/ports/grep.mk
+++ b/repos/ports/ports/grep.mk
@@ -9,7 +9,7 @@ GNUGREP_KEY = GNU
 #
 PORTS += $(GNUGREP)
 
-prepare:: $(CONTRIB_DIR)/$(GNUGREP)
+prepare-grep: $(CONTRIB_DIR)/$(GNUGREP)
 
 #
 # Port-specific local rules
@@ -28,3 +28,5 @@ $(DOWNLOAD_DIR)/$(GNUGREP_TXZ).verified: $(DOWNLOAD_DIR)/$(GNUGREP_TXZ) \
 	$(VERBOSE)$(SIGVERIFIER) $(DOWNLOAD_DIR)/$(GNUGREP_TXZ) $(DOWNLOAD_DIR)/$(GNUGREP_SIG) $(GNUGREP_KEY)
 	$(VERBOSE)touch $@
 
+clean-grep:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(GNUGREP)
diff --git a/repos/ports/ports/lighttpd.mk b/repos/ports/ports/lighttpd.mk
index 5709e8c03..71ed4daf8 100644
--- a/repos/ports/ports/lighttpd.mk
+++ b/repos/ports/ports/lighttpd.mk
@@ -12,7 +12,7 @@ LIGHTTPD_KEY      = stbuehler@lighttpd.net
 #
 PORTS += $(LIGHTTPD)
 
-prepare:: $(CONTRIB_DIR)/$(LIGHTTPD)
+prepare-lighttpd: $(CONTRIB_DIR)/$(LIGHTTPD)
 
 #
 # Port-specific local rules
@@ -31,3 +31,6 @@ $(DOWNLOAD_DIR)/$(LIGHTTPD_TGZ).verified: $(DOWNLOAD_DIR)/$(LIGHTTPD_TGZ) \
 $(CONTRIB_DIR)/$(LIGHTTPD): $(DOWNLOAD_DIR)/$(LIGHTTPD_TGZ).verified
 	$(VERBOSE)tar xfz $(<:.verified=) -C $(CONTRIB_DIR) && touch $@
 	$(VERBOSE)patch -N -p1 < src/app/lighttpd/disable_gethostbyaddr_fcntl.patch
+
+clean-lighttpd:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(LIGHTTPD)
diff --git a/repos/ports/ports/lynx.mk b/repos/ports/ports/lynx.mk
index 31669c4a2..2bb5e9a68 100644
--- a/repos/ports/ports/lynx.mk
+++ b/repos/ports/ports/lynx.mk
@@ -10,7 +10,7 @@ LYNX_KEY     = dickey@sf1.isc.org
 #
 PORTS += $(LYNX)
 
-prepare:: $(CONTRIB_DIR)/$(LYNX)
+prepare-lynx: $(CONTRIB_DIR)/$(LYNX)
 
 #
 # Port-specific local rules
@@ -34,3 +34,6 @@ $(DOWNLOAD_DIR)/$(LYNX_TGZ).verified: $(DOWNLOAD_DIR)/$(LYNX_TGZ)
 $(CONTRIB_DIR)/$(LYNX): $(DOWNLOAD_DIR)/$(LYNX_TGZ).verified
 	$(VERBOSE)tar xfz $(<:.verified=) -C $(CONTRIB_DIR) && touch $@
 	$(VERBOSE)patch -d contrib/ -N -p0 < src/noux-pkg/lynx/build.patch
+
+clean-lynx:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(LYNX)
diff --git a/repos/ports/ports/make.mk b/repos/ports/ports/make.mk
index 3fe403c90..81682b7a7 100644
--- a/repos/ports/ports/make.mk
+++ b/repos/ports/ports/make.mk
@@ -11,7 +11,7 @@ GNUMAKE_KEY      = GNU
 #
 PORTS += $(GNUMAKE)
 
-prepare:: $(CONTRIB_DIR)/$(GNUMAKE)
+prepare-make: $(CONTRIB_DIR)/$(GNUMAKE)
 
 #
 # Port-specific local rules
@@ -30,3 +30,5 @@ $(DOWNLOAD_DIR)/$(GNUMAKE_TGZ).verified: $(DOWNLOAD_DIR)/$(GNUMAKE_TGZ) \
 $(CONTRIB_DIR)/$(GNUMAKE): $(DOWNLOAD_DIR)/$(GNUMAKE_TGZ).verified
 	$(VERBOSE)tar xfz $(<:.verified=) -C $(CONTRIB_DIR) && touch $@
 
+clean-make:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(GNUMAKE)
diff --git a/repos/ports/ports/netcat.mk b/repos/ports/ports/netcat.mk
index 58a6d67a2..00704a756 100644
--- a/repos/ports/ports/netcat.mk
+++ b/repos/ports/ports/netcat.mk
@@ -8,7 +8,7 @@ GNUNETCAT_URL = http://downloads.sourceforge.net/sourceforge/netcat/netcat-$(GNU
 #
 PORTS += $(GNUNETCAT)
 
-prepare:: $(CONTRIB_DIR)/$(GNUNETCAT)
+prepare-netcat: $(CONTRIB_DIR)/$(GNUNETCAT)
 
 #
 # Port-specific local rules
@@ -19,3 +19,5 @@ $(DOWNLOAD_DIR)/$(GNUNETCAT_TBZ):
 $(CONTRIB_DIR)/$(GNUNETCAT): $(DOWNLOAD_DIR)/$(GNUNETCAT_TBZ)
 	$(VERBOSE)tar xfj $< -C $(CONTRIB_DIR) && touch $@
 
+clean-netcat:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(GNUNETCAT)
diff --git a/repos/ports/ports/netperf.mk b/repos/ports/ports/netperf.mk
index 27f4b20a4..01008ddb2 100644
--- a/repos/ports/ports/netperf.mk
+++ b/repos/ports/ports/netperf.mk
@@ -27,7 +27,7 @@ apply_patches-netperf: checkout-netperf
 		xargs -ixxx sh -c "patch -p0 -r - -N -d $(CONTRIB_DIR)/$(NETPERF) < xxx" || true
 	$(VERBOSE)echo '#define NETPERF_VERSION "$(NETPERF_VERSION)"' >$(CONTRIB_DIR)/$(NETPERF)/src/netperf_version.h
 
-prepare:: apply_patches-netperf
+prepare-netperf: apply_patches-netperf
 
 clean-netperf:
 	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(NETPERF)
diff --git a/repos/ports/ports/openssh.mk b/repos/ports/ports/openssh.mk
index b918c9bc1..c601af54b 100644
--- a/repos/ports/ports/openssh.mk
+++ b/repos/ports/ports/openssh.mk
@@ -11,7 +11,7 @@ OPENSSH_KEY      = 3981992A1523ABA079DBFC66CE8ECB0386FF9C48
 #
 PORTS += $(OPENSSH)
 
-prepare:: $(CONTRIB_DIR)/$(OPENSSH)
+prepare-openssh: $(CONTRIB_DIR)/$(OPENSSH)
 
 #
 # Port-specific local rules
@@ -32,3 +32,6 @@ $(CONTRIB_DIR)/$(OPENSSH): $(DOWNLOAD_DIR)/$(OPENSSH_TGZ).verified
 	$(VERBOSE)patch -d contrib/ -N -p0 < src/noux-pkg/openssh/monitor_fdpass.c.patch
 	$(VERBOSE)patch -d contrib/ -N -p0 < src/noux-pkg/openssh/sshconnect.h.patch
 	$(VERBOSE)patch -d contrib/ -N -p0 < src/noux-pkg/openssh/includes_h.patch
+
+clean-openssh:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(OPENSSH)
diff --git a/repos/ports/ports/sed.mk b/repos/ports/ports/sed.mk
index a72e0b35c..d9e171fce 100644
--- a/repos/ports/ports/sed.mk
+++ b/repos/ports/ports/sed.mk
@@ -9,7 +9,7 @@ GNUSED_KEY = GNU
 #
 PORTS += $(GNUSED)
 
-prepare:: $(CONTRIB_DIR)/$(GNUSED)
+prepare-sed: $(CONTRIB_DIR)/$(GNUSED)
 
 #
 # Port-specific local rules
@@ -28,3 +28,6 @@ $(DOWNLOAD_DIR)/$(GNUSED_TGZ).verified: $(DOWNLOAD_DIR)/$(GNUSED_TGZ) \
 	$(VERBOSE)$(SIGVERIFIER) $(DOWNLOAD_DIR)/$(GNUSED_TGZ) $(DOWNLOAD_DIR)/$(GNUSED_SIG) $(GNUSED_KEY)
 	$(VERBOSE)touch $@
 
+clean-sed:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(SED)
+
diff --git a/repos/ports/ports/seoul.mk b/repos/ports/ports/seoul.mk
index 88f5fbd3f..8d7b5b0a9 100644
--- a/repos/ports/ports/seoul.mk
+++ b/repos/ports/ports/seoul.mk
@@ -24,7 +24,7 @@ python_not_installed:
 	@false;
 endif
 
-prepare:: fetch-new-version $(CONTRIB_DIR)/$(SEOUL)/genode_prepared
+prepare-seoul: fetch-new-version $(CONTRIB_DIR)/$(SEOUL)/genode_prepared
 
 #
 # Port-specific local rules
@@ -63,3 +63,6 @@ $(CONTRIB_DIR)/$(SEOUL)/genode_prepared: $(CONTRIB_DIR)/$(SEOUL)
 	touch $(CURDIR)/$@
 
 .PHONY: fetch-new-version
+
+clean-seoul:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(SEOUL)
diff --git a/repos/ports/ports/vim.mk b/repos/ports/ports/vim.mk
index efd4ea3d5..a88b81062 100644
--- a/repos/ports/ports/vim.mk
+++ b/repos/ports/ports/vim.mk
@@ -13,7 +13,7 @@ PORTS += $(VIM)
 #
 $(call check_tool,sed)
 
-prepare:: $(CONTRIB_DIR)/$(VIM)
+prepare-vim: $(CONTRIB_DIR)/$(VIM)
 
 #
 # Port-specific local rules
@@ -40,3 +40,6 @@ $(CONTRIB_DIR)/$(VIM): $(DOWNLOAD_DIR)/$(VIM_TBZ2).verified
 	@#
 	$(VERBOSE)sed -i "/default_vim_dir/s/.(VIMRCLOC)/\/share\/vim/" $@/src/Makefile
 	$(VERBOSE)patch -d $(CONTRIB_DIR)/$(VIM) -N -p1 < src/noux-pkg/vim/build.patch
+
+clean-vim:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(VIM)
diff --git a/repos/ports/ports/virtualbox.mk b/repos/ports/ports/virtualbox.mk
index b7fa31c3b..863045f6b 100644
--- a/repos/ports/ports/virtualbox.mk
+++ b/repos/ports/ports/virtualbox.mk
@@ -57,7 +57,7 @@ apply_patches:
 		patch -p0 -N -d $(CONTRIB_DIR)/$(VIRTUALBOX) -i $$p; \
 	done
 
-prepare:: $(CONTRIB_DIR)/$(VIRTUALBOX) apply_patches
+prepare-virtualbox: $(CONTRIB_DIR)/$(VIRTUALBOX) apply_patches
 
 #
 # Port-specific local rules
@@ -80,3 +80,6 @@ $(CONTRIB_DIR)/$(VIRTUALBOX): $(DOWNLOAD_DIR)/$(VIRTUALBOX_TBZ2).verified
 	rm $(CONTRIB_DIR)/$(VIRTUALBOX)/src/VBox/Frontends/VBoxBFE/SDLConsole.h && \
 	rm $(CONTRIB_DIR)/$(VIRTUALBOX)/src/VBox/Frontends/VBoxBFE/SDLFramebuffer.h; \
 	if [ $$? -ne 0 ]; then rm -r $(CONTRIB_DIR)/$(VIRTUALBOX); exit 1; fi
+
+clean-virtualbox:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(VIRTUALBOx)
diff --git a/repos/ports/ports/which.mk b/repos/ports/ports/which.mk
index 10b4f6325..a310f5162 100644
--- a/repos/ports/ports/which.mk
+++ b/repos/ports/ports/which.mk
@@ -11,7 +11,7 @@ WHICH_KEY      = GNU
 #
 PORTS += $(WHICH)
 
-prepare:: $(CONTRIB_DIR)/$(WHICH)
+prepare-which: $(CONTRIB_DIR)/$(WHICH)
 
 #
 # Port-specific local rules
@@ -29,3 +29,6 @@ $(DOWNLOAD_DIR)/$(WHICH_TGZ).verified: $(DOWNLOAD_DIR)/$(WHICH_TGZ) \
 
 $(CONTRIB_DIR)/$(WHICH): $(DOWNLOAD_DIR)/$(WHICH_TGZ).verified
 	$(VERBOSE)tar xfz $(<:.verified=) -C $(CONTRIB_DIR) && touch $@
+
+clean-which:
+	$(VERBOSE)rm -rf $(CONTRIB_DIR)/$(WHICH)
diff --git a/tool/README b/tool/README
index d354cd7f9..3cb7e7b01 100644
--- a/tool/README
+++ b/tool/README
@@ -54,3 +54,9 @@ of Genode.
   Autopilot is a tool for the automatic execution of run scripts among multiple
   base platforms.
 
+:'prepare.mk':
+
+  Tool for downloading and integrating 3rd-party source codes with Genode.
+  This file is included by the makefiles in the root of source-code
+  repositories that interface with 3rd-party code, e.g., libports and ports.
+
diff --git a/tool/prepare.mk b/tool/prepare.mk
new file mode 100644
index 000000000..f1222b844
--- /dev/null
+++ b/tool/prepare.mk
@@ -0,0 +1,84 @@
+#
+# \brief  Download and unpack upstream library source codes
+# \author Norman Feske
+# \date   2009-10-16
+#
+
+#
+# Print help information by default
+#
+help::
+
+VERBOSE     ?= @
+ECHO         = @echo
+DOWNLOAD_DIR = download
+CONTRIB_DIR  = contrib
+GNU_FIND     = find
+SHELL        = bash
+SIGVERIFIER  = $(CURDIR)/../../tool/download_sigver
+HASHVERIFIER = $(CURDIR)/../../tool/download_hashver
+
+#
+# Create download and contrib directory so that '<port>.mk' files
+# do not need to care for them.
+#
+prepare: $(DOWNLOAD_DIR) $(CONTRIB_DIR)
+
+#
+# Utility to check if a tool is installed
+#
+check_tool = $(if $(shell which $(1)),,$(error Need to have '$(1)' installed.))
+
+$(call check_tool,wget)
+$(call check_tool,patch)
+$(call check_tool,gpg)
+$(call check_tool,md5sum)
+$(call check_tool,sha1sum)
+$(call check_tool,sha256sum)
+
+#
+# Include information about available ports
+#
+# Each '<port>.mk' file in the 'ports/' directory extends the following
+# variables:
+#
+# PORTS     - list names of the available ports, e.g., 'freetype-2.3.9'
+# GEN_DIRS  - list of automatically generated directories
+# GEN_FILES - list of automatically generated files
+#
+# Furthermore, each '<port>.mk' file extends the 'prepare' rule for
+# downloading and unpacking the corresponding upstream sources.
+#
+PKG ?= $(patsubst ports/%.mk,%,$(wildcard ports/*.mk))
+include $(addprefix ports/,$(addsuffix .mk,$(PKG)))
+
+help::
+	$(ECHO)
+	$(ECHO) "Download and unpack upstream source codes:"
+	@for i in $(PORTS); do echo "  $$i"; done
+	$(ECHO)
+	$(ECHO) "Downloads will be placed into the '$(DOWNLOAD_DIR)/' directory."
+	$(ECHO) "Source codes will be unpacked in the '$(CONTRIB_DIR)/' directory."
+	$(ECHO)
+	$(ECHO) "--- available commands ---"
+	$(ECHO) "prepare  - download and unpack upstream source codes"
+	$(ECHO) "clean    - remove upstream source codes"
+	$(ECHO) "cleanall - remove upstream source codes and downloads"
+	$(ECHO)
+	$(ECHO) "--- available arguments ---"
+	$(ECHO) "PKG=<package-list>  - prepare only the specified packages,"
+	$(ECHO) "                      each package specified w/o version number"
+
+prepare: $(addprefix prepare-,$(PKG))
+
+$(DOWNLOAD_DIR) $(CONTRIB_DIR):
+	$(VERBOSE)mkdir -p $@
+
+clean: $(addprefix clean-,$(PKG))
+	$(VERBOSE)if [ -d $(CONTRIB_DIR) ]; then \
+                 $(GNU_FIND) $(CONTRIB_DIR) -depth -type d -empty -delete; fi
+
+cleanall: clean
+	$(VERBOSE)rm -rf $(DOWNLOAD_DIR)
+
+.NOTPARALLEL: