Test for combining loader with chroot

os/run/chroot_loader.run

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+#
+# \brief  Test for using chroot on Linux
+# \author Norman Feske
+# \date   2012-06-06
+#
+#
+if {![have_spec linux]} { puts "Run script requires Linux"; exit 0 }
+
+#
+# Build
+#
+
+build { core init app/chroot drivers/timer/linux test/timer
+        server/loader test/chroot_loader }
+
+if {[catch { exec which setcap }]} {
+	puts stderr "Error: setcap not available, please install the libcap2-bin package"
+	return 0
+}
+
+
+create_boot_directory
+
+#
+# Generate config
+#
+
+set config {
+	<config>
+		<parent-provides>
+			<service name="ROM"/>
+			<service name="LOG"/>
+			<service name="CAP"/>
+			<service name="RAM"/>
+			<service name="CPU"/>
+			<service name="RM"/>
+			<service name="PD"/>
+			<service name="SIGNAL"/>
+		</parent-provides>
+		<default-route>
+			<any-service> <parent/> <any-child/> </any-service>
+		</default-route>
+		<start name="timer">
+			<resource name="RAM" quantum="1M"/>
+			<provides><service name="Timer"/></provides>
+		</start>
+		<start name="loader">
+			<resource name="RAM" quantum="1M"/>
+			<provides><service name="Loader"/></provides>
+		</start>
+		<start name="test-chroot_loader">
+			<resource name="RAM" quantum="32M"/>
+			<config>
+				<static_test  chroot_path="chroot_path_1" />
+				<dynamic_test chroot_path="chroot_path_2" />
+			</config>
+		</start>
+	</config>
+}
+
+proc chroot_path { id } { return "/tmp/chroot-test-$id" }
+
+proc chroot_cwd_path { id } { return "[chroot_path $id][pwd]/[run_dir]" }
+
+proc chroot_genode_tmp_path { id } { return "[chroot_path $id]/tmp/genode-[exec id -u]" }
+
+proc cleanup_chroot { } {
+	foreach id { 1 2 } {
+		catch { exec sudo umount -l [chroot_cwd_path $id] }
+		catch { exec sudo umount -l [chroot_genode_tmp_path $id] }
+		catch { exec sudo umount -l [chroot_path $id]/lib }
+		catch { exec rm -rf [chroot_path $id] }
+	}
+}
+
+# replace 'chroot_path' markers in config with actual paths
+foreach id { 1 2 } {
+	regsub "chroot_path_$id" $config [chroot_path $id] config }
+
+install_config $config
+
+#
+# Copy boot modules into run directory
+#
+# We cannot use the predefined 'build_boot_image' function here because
+# this would create mere symlinks. However, we want to hardlink the
+# run directory into the chroot environment. If the directory entries
+# were symlinks, those would point to nowhere within the chroot.
+#
+foreach binary { core init chroot timer loader test-chroot_loader test-timer} {
+	exec cp -H  bin/$binary [run_dir] }
+
+#
+# Grant chroot permission to 'chroot' tool
+#
+# CAP_SYS_ADMIN is needed for bind mounting genode runtime directories
+# CAP_SYS_CHROOT is needed to perform the chroot syscall
+#
+exec sudo setcap cap_sys_admin,cap_sys_chroot=ep [run_dir]/chroot
+
+#
+# Setup chroot environment
+#
+
+# start with fresh directory
+cleanup_chroot
+foreach id { 1 2 } {
+	exec mkdir -p [chroot_path $id]
+	exec mkdir -p [chroot_path $id]/lib
+
+	# bind mount '/lib' as need libc within the chroot environment
+	exec sudo mount --bind /lib [chroot_path $id]/lib
+}
+
+#
+# Execute test case
+#
+run_genode_until {.*--- chroot-loader test finished ---\s*\n} 60
+
+#
+# Validate log output
+#
+
+if {[regexp -all -- {--- timer test ---} $output] != 6} {
+	puts stderr "Number of spawned subsystems differs from 6"
+	exit 2
+}
+
+if {![regexp -- {chroot-1 -> test-timer] wait 2/10} $output]} {
+	puts stderr "Long-running timer test has made too little progress"
+	exit 3
+}
+
+#
+# Remove artifacts created while running the test
+#
+cleanup_chroot
+
+# vi: set ft=tcl :

os/src/test/chroot_loader/main.cc

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+/*
+ * \brief  Test for dynamically starting chrooted subsystems via the loader
+ * \author Norman Feske
+ * \date   2012-06-06
+ *
+ * This test creates two subsystems, each residing in a dedicated chroot
+ * environment, by combining the loader service with the chroot mechanism.
+ * One subsystem runs infinitely. The other subsystem will be repeatedly
+ * started and killed.
+ */
+
+/* Genode includes */
+#include <base/snprintf.h>
+#include <loader_session/connection.h>
+#include <os/config.h>
+#include <timer_session/connection.h>
+
+
+/*******************************************************
+ ** Helpers for obtaining test parameters from config **
+ *******************************************************/
+
+static char const *chroot_path_from_config(char const *node_name,
+                                           char *dst, Genode::size_t dst_len)
+{
+	Genode::config()->xml_node().sub_node(node_name)
+		.attribute("chroot_path").value(dst, dst_len);
+	return dst;
+}
+
+
+static char const *chroot_path_of_static_test()
+{
+	static char buf[1024];
+	return chroot_path_from_config("static_test", buf, sizeof(buf));
+}
+
+
+static char const *chroot_path_of_dynamic_test()
+{
+	static char buf[1024];
+	return chroot_path_from_config("dynamic_test", buf, sizeof(buf));
+}
+
+
+/**********
+ ** Test **
+ **********/
+
+/**
+ * Return format string used as template for the subsystem configuration.
+ *
+ * Note the format-string argument used for inserting the chroot path.
+ */
+static char const *config_template()
+{
+	return "<config verbose=\"yes\">\n"
+	       "  <root path=\"%s\" />\n"
+	       "  <parent-provides>\n"
+	       "    <service name=\"ROM\"/>\n"
+	       "    <service name=\"LOG\"/>\n"
+	       "    <service name=\"CAP\"/>\n"
+	       "    <service name=\"RAM\"/>\n"
+	       "    <service name=\"CPU\"/>\n"
+	       "    <service name=\"RM\"/>\n"
+	       "    <service name=\"PD\"/>\n"
+	       "    <service name=\"Timer\"/>\n"
+	       "  </parent-provides>\n"
+	       "  <default-route>\n"
+	       "    <any-service> <parent/> </any-service>\n"
+	       "  </default-route>\n"
+	       "  <start name=\"test-timer\">\n"
+	       "    <resource name=\"RAM\" quantum=\"1G\"/>\n"
+	       "  </start>\n"
+	       "</config>\n";
+}
+
+
+/**
+ * Chroot subsystem corresponding to a loader session
+ */
+class Chroot_subsystem
+{
+	private:
+
+		Loader::Connection _loader;
+
+		char _label[32];
+
+		/**
+		 * Import data as ROM module into the subsystem-specific ROM service
+		 */
+		void _import_rom_module(char const *name, void *ptr, Genode::size_t size)
+		{
+			using namespace Genode;
+
+			Dataspace_capability ds = _loader.alloc_rom_module(name, size);
+
+			/* fill ROM module with data */
+			char *local_addr = env()->rm_session()->attach(ds);
+			memcpy(local_addr, ptr, size);
+			env()->rm_session()->detach(local_addr);
+
+			_loader.commit_rom_module(name);
+		}
+
+	public:
+
+		Chroot_subsystem(char const *chroot_path, Genode::size_t ram_quota)
+		:
+			_loader(ram_quota)
+		{
+			using namespace Genode;
+
+			/*
+			 * Generate Genode configuration of the new subsystem and import
+			 * it into the subsystem's loader session as a ROM module named
+			 * "config".
+			 */
+			char buf[strlen(chroot_path) + strlen(config_template()) + 1];
+			snprintf(buf, sizeof(buf), config_template(), chroot_path);
+
+			_import_rom_module("config", buf, strlen(buf) + 1);
+
+			/*
+			 * Name of the Genode binary is start as the root of the new
+			 * subsystem.
+			 */
+			char const *chroot_binary_name = "chroot";
+
+			/*
+			 * Generate unique label name using a counter
+			 *
+			 * The label appears in the LOG output of the loaded subsystem.
+			 * Technically, it does need to be unique. It is solely used
+			 * for validating the test in the run script.
+			 */
+			static int cnt = 0;
+			snprintf(_label, sizeof(_label), "%s-%d", chroot_binary_name, ++cnt);
+
+			/* start execution of new subsystem */
+			_loader.start(chroot_binary_name, Loader::Session::Name(_label));
+		}
+};
+
+
+int main(int, char **)
+{
+	Genode::printf("--- chroot-loader test started ---\n");
+
+	static Chroot_subsystem static_subsystem(chroot_path_of_static_test(),
+	                                         2*1024*1024);
+
+	static Timer::Connection timer;
+
+	for (unsigned i = 0; i < 5; i++) {
+
+		PLOG("dynamic test iteration %d", i);
+
+		Chroot_subsystem subsystem(chroot_path_of_dynamic_test(),
+		                           2*1024*1024);
+
+		/* grant the subsystem one second of life */
+		timer.msleep(1000);
+
+		/*
+		 * The local 'dynamic_subsystem' instance will be destructed at the of
+		 * the loop body.
+		 */
+	}
+
+	Genode::printf("--- chroot-loader test finished ---\n");
+	return 0;
+}

os/src/test/chroot_loader/target.mk

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+TARGET = test-chroot_loader
+SRC_CC = main.cc
+LIBS  += cxx env