tool/ports: add tool to check source availability

The 'check_port_source' checks whether all remote sources defined for a given
port are currently available. It returns zero, when all remote resources are
available.

Fix #1430

tool/ports/check_port_source

@@ -0,0 +1,27 @@
+#!/usr/bin/make -f
+
+#
+# \brief  Tool for checking remote 3rd-party sources
+# \author Stefan Kalkowski
+# \date   2015-03-04
+#
+
+#
+# Determine Genode base directory based on the known location of the
+# 'create_builddir' tool within the Genode source tree
+#
+export GENODE_DIR := $(realpath $(dir $(MAKEFILE_LIST))/../..)
+
+include $(GENODE_DIR)/tool/ports/mk/front_end.inc
+include $(GENODE_DIR)/tool/ports/mk/check_port_arg.inc
+
+usage:
+	@$(ECHO)
+	@$(ECHO) "--- check remote sources of port ---"
+	@$(ECHO) "usage: check_port_source <port-name>"
+	@$(ECHO)
+
+$(TARGET):
+	$(VERBOSE)$(MAKE) --no-print-directory \
+	                  -f $(GENODE_DIR)/tool/ports/mk/check.mk \
+	                  PORT=$(PORT) VERBOSE=$(VERBOSE)

tool/ports/mk/check.mk

@@ -0,0 +1,61 @@
+#
+# \brief  Check for remote 3rd-party source code
+# \author Stefan Kalkowski
+# \date   2015-03-04
+#
+# This makefile must be invoked from the port directory.
+#
+# Arguments:
+#
+# PORT - port description file
+#
+
+check:
+
+#
+# Utility to check if a tool is installed
+#
+check_tool = $(if $(shell which $(1)),,$(error Need to have '$(1)' installed.))
+
+$(call check_tool,curl)
+$(call check_tool,git)
+$(call check_tool,svn)
+
+# repository that contains the port description, used to look up patch files
+REP_DIR := $(realpath $(dir $(PORT))/..)
+
+#
+# Include definitions provided by the port description file
+#
+include $(PORT)
+
+#
+# Include common definitions
+#
+include $(GENODE_DIR)/tool/ports/mk/common.inc
+
+#
+# Default rule that triggers the actual check steps
+#
+check: $(DOWNLOADS)
+
+#
+# Check source codes from a Git repository
+#
+%.git:
+	$(VERBOSE)git ls-remote --exit-code $(URL($*)) >/dev/null 2>&1
+
+#
+# Check source codes from Subversion repository
+#
+%.svn:
+	$(VERBOSE)svn info -r $(REV($*)) $(URL($*)) >/dev/null 2>&1
+
+#
+# Check plain remote file
+#
+%.file:
+	$(VERBOSE)curl -f -L -k -r -2 $(URL($*)) > /dev/null 2>&1
+
+%.archive: %.file
+	$(VERBOSE)true