vfs/xoroshiro: add PRNG plugin using Xoroshiro128+

This plugin provides a PRNG based on the Xoroshiro128+ algorithm
that reseeds itself after a specific amount of state was consumed.

For more detailed information please take a look at its README in
'repos/os/src/lib/vfs/xoroshiro/README'.

Fixes genodelabs#5407.

repos/gems/run/vfs_xoroshiro.run

@@ -0,0 +1,94 @@
+build { lib/vfs_xoroshiro lib/vfs_jitterentropy }
+
+create_boot_directory
+
+import_from_depot \
+	[depot_user]/src/[base_src] \
+	[depot_user]/src/coreutils \
+	[depot_user]/src/init \
+	[depot_user]/src/fs_rom \
+	[depot_user]/src/libc \
+	[depot_user]/src/vfs \
+	[depot_user]/src/posix
+
+install_config {
+	<config verbose="yes">
+		<parent-provides>
+			<service name="ROM"/>
+			<service name="LOG"/>
+			<service name="RM"/>
+			<service name="CPU"/>
+			<service name="PD"/>
+			<service name="IRQ"/>
+			<service name="IO_MEM"/>
+			<service name="IO_PORT"/>
+		</parent-provides>
+
+		<default-route>
+			<any-service> <parent/> </any-service>
+		</default-route>
+		<default caps="100"/>
+
+		<start name="timer">
+			<resource name="RAM" quantum="1M"/>
+			<provides><service name="Timer"/></provides>
+		</start>
+
+		<start name="vfs">
+			<resource name="RAM" quantum="4M"/>
+			<provides><service name="File_system"/></provides>
+			<config>
+				<vfs>
+					<ram/>
+					<tar name="coreutils.tar" />
+				</vfs>
+				<default-policy root="/" writeable="yes"/>
+			</config>
+		</start>
+
+		<start name="vfs_rom">
+			<resource name="RAM" quantum="10M"/>
+			<binary name="fs_rom"/>
+			<provides> <service name="ROM"/> </provides>
+			<config/>
+			<route>
+				<service name="File_system"> <child name="vfs"/> </service>
+				<any-service> <parent/> </any-service>
+			</route>
+		</start>
+
+		<start name="/bin/dd" caps="500">
+			<resource name="RAM" quantum="16M"/>
+			<config>
+				<libc stdin="/dev/null" stdout="/dev/log" stderr="/dev/log"
+				      rtc="/dev/null"/>
+				<vfs>
+					<dir name="dev">
+						<log/>
+						<null/>
+						<jitterentropy name="entropy"/>
+						<xoroshiro name="random" seed_file="/dev/entropy"/>
+					</dir>
+				</vfs>
+				<arg value="dd"/>
+				<arg value="if=/dev/random"/>
+				<arg value="of=/dev/null"/>
+				<arg value="bs=1M"/>
+				<arg value="count=128"/>
+			</config>
+			<route>
+				<service name="File_system"> <child name="vfs"/> </service>
+				<service name="ROM" label_suffix=".lib.so"> <parent/> </service>
+				<service name="ROM" label_last="/bin/dd"> <child name="vfs_rom"/> </service>
+				<any-service> <parent/> <any-child/> </any-service>
+			</route>
+		</start>
+
+	</config>
+}
+
+build_boot_image [build_artifacts]
+
+append qemu_args " -nographic "
+
+run_genode_until "child .* exited with exit value 0.*\n" 20

repos/os/lib/mk/vfs_xoroshiro.mk

@@ -0,0 +1,12 @@
+VFS_DIR := $(REP_DIR)/src/lib/vfs/xoroshiro
+
+SRC_CC := vfs.cc
+
+# for base/internal/xoroshiro.h
+REP_INC_DIR += src/include/base/internal
+
+LD_OPT += --version-script=$(VFS_DIR)/symbol.map
+
+SHARED_LIB := yes
+
+vpath %.cc $(VFS_DIR)

repos/os/recipes/src/vfs_xoroshiro/content.mk

@@ -0,0 +1,17 @@
+MIRROR_FROM_REP_DIR := src/lib/vfs/xoroshiro lib/mk/vfs_xoroshiro.mk
+
+content: $(MIRROR_FROM_REP_DIR) LICENSE
+
+$(MIRROR_FROM_REP_DIR):
+	$(mirror_from_rep_dir)
+
+MIRROR_FROM_BASE_DIR := src/include/base/internal/xoroshiro.h
+
+content: $(MIRROR_FROM_BASE_DIR)
+
+$(MIRROR_FROM_BASE_DIR):
+	mkdir -p $(dir $@)
+	cp -r $(addprefix $(GENODE_DIR)/repos/base/,$@) $(dir $@)
+
+LICENSE:
+	cp $(GENODE_DIR)/LICENSE $@

repos/os/recipes/src/vfs_xoroshiro/hash

@@ -0,0 +1 @@
+2024-12-16 af40f4293fa0bc3a44ff27b6a174d37a0ecce3eb

repos/os/recipes/src/vfs_xoroshiro/used_apis

@@ -0,0 +1,3 @@
+base
+os
+vfs

repos/os/src/lib/vfs/xoroshiro/README

@@ -0,0 +1,20 @@
+The VFS xoroshiro plugin provides a PRNG based on the Xoroshiro12+
+algorithm. It is seeded initially and reseeded regularly after a fixed
+amount of bytes, around 1 MiB, were produced by reading a seed file.
+
+The plugin supports the following configuration options:
+
+* :name: sets the file-name under which the plugins exposes itself
+         to the VFS, the default is 'xoroshiro'.
+
+* :seed_file: specifies the file in the VFS that is read to reseed
+              the PRNG, the default is '/dev/entropy'.
+
+The following examplary config snippets illustrates its usage:
+
+! <vfs>
+!   <dir name="dev">
+!     <jitterentropy name="entropy"/>
+!     <xoroshiro     name="random"/>
+!   </dir>
+! </vfs>

repos/os/src/lib/vfs/xoroshiro/symbol.map

@@ -0,0 +1,9 @@
+{
+	global:
+
+		vfs_file_system_factory;
+
+	local:
+
+		*;
+};