app/sequence: execute components in sequence

Fix #2476
This commit is contained in:
Emery Hemingway 2017-08-09 19:24:27 -05:00 committed by Christian Helmuth
parent 523b317fe6
commit 5f35175644
4 changed files with 388 additions and 0 deletions

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#
# \brief Test of sequence utility
# \author Emery Hemingway
# \date 2017-08-09
#
#
# Build
#
build { app/sequence test/libc }
create_boot_directory
import_from_depot \
genodelabs/src/[base_src] \
genodelabs/src/init \
genodelabs/src/vfs \
#
# Generate config
#
set config {
<config>
<parent-provides>
<service name="ROM"/>
<service name="PD"/>
<service name="RM"/>
<service name="CPU"/>
<service name="LOG"/>
</parent-provides>
<default-route> <any-service> <parent/> </any-service> </default-route>
<start name="log-1" caps="64">
<binary name="vfs"/>
<resource name="RAM" quantum="4M"/>
<provides> <service name="File_system"/> </provides>
<config>
<vfs> <log/> </vfs>
<default-policy writeable="yes"/>
</config>
</start>
<start name="log-2" caps="64">
<binary name="vfs"/>
<resource name="RAM" quantum="4M"/>
<provides> <service name="File_system"/> </provides>
<config>
<vfs> <log/> </vfs>
<default-policy writeable="yes"/>
</config>
</start>
<start name="log-3" caps="64">
<binary name="vfs"/>
<resource name="RAM" quantum="4M"/>
<provides> <service name="File_system"/> </provides>
<config>
<vfs> <log/> </vfs>
<default-policy writeable="yes"/>
</config>
</start>
<start name="sequence" caps="200">
<resource name="RAM" quantum="512M"/>
<route>
<service name="File_system" label_prefix="test-libc-1">
<child name="log-1"/> </service>
<service name="File_system" label_prefix="test-libc-2">
<child name="log-2"/> </service>
<service name="File_system" label_prefix="test-libc-3">
<child name="log-3"/> </service>
<any-service> <parent/> </any-service>
</route>
<config>
<start name="test-libc-1">
<binary name="test-libc"/>
<config>
<vfs> <dir name="dev"> <fs/> </dir> </vfs>
<libc stdout="/dev/log"/>
</config>
</start>
<start name="test-libc-2">
<binary name="test-libc"/>
<config>
<vfs> <dir name="dev"> <fs/> </dir> </vfs>
<libc stdout="/dev/log"/>
</config>
</start>
<start name="test-libc-3">
<binary name="test-libc"/>
<config>
<vfs> <dir name="dev"> <fs/> </dir> </vfs>
<libc stdout="/dev/log"/>
</config>
</start>
</config>
</start>
</config>
}
install_config $config
#
# Boot modules
#
build_boot_image {
sequence
libc.lib.so libm.lib.so posix.lib.so
test-libc
}
#
# Execute test case
#
append qemu_args " -nographic "
run_genode_until {.*child "sequence" exited with exit value 0.*} 30
# vi: set ft=tcl :

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This directory contains a simple utility to serialize the execution of
multiple components. It is configured with "start" XML nodes much like
_init_ however this component relies on its parent to manage all routing
and resources, with the exception of a "config" ROM. No services are
propagated from children to the parent.
A sample configuration to start a consumer after a producer has exited:
! <start name="sequence" caps="100">
! <resource name="RAM" quantum="128M"/>
! <route>
! <any-service> <parent/> <any-child/> </any-service>
! </route>
! <config>
! <start name="producer">
! <config>
! ...
! </config>
! </start>
! <start name="consumer">
! <config>
! ...
! </config>
! </start>
! </config>
! </start>

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/*
* \brief Utility to sequence component execution
* \author Emery Hemingway
* \date 2017-08-09
*/
/*
* Copyright (C) 2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#include <init/child_policy.h>
#include <base/attached_rom_dataspace.h>
#include <os/child_policy_dynamic_rom.h>
#include <base/sleep.h>
#include <base/child.h>
#include <base/component.h>
namespace Sequence {
using namespace Genode;
struct Child;
struct Main;
}
struct Sequence::Child : Genode::Child_policy
{
Genode::Env &_env;
Heap _services_heap { _env.pd(), _env.rm() };
Xml_node const _start_node;
Name const _name = _start_node.attribute_value("name", Name());
Binary_name _start_binary()
{
Binary_name name;
try {
_start_node.sub_node("binary").attribute("name").value(&name);
return name != "" ? name : _name;
}
catch (...) { return _name; }
}
Binary_name const _binary_name = _start_binary();
Child_policy_dynamic_rom_file _config_policy {
_env.rm(), "config", _env.ep().rpc_ep(), &_env.pd() };
class Parent_service : public Genode::Parent_service
{
private:
Registry<Parent_service>::Element _reg_elem;
public:
Parent_service(Registry<Parent_service> &registry, Env &env,
Service::Name const &name)
:
Genode::Parent_service(env, name), _reg_elem(registry, *this)
{ }
};
Registry<Parent_service> _parent_services;
Genode::Child _child { _env.rm(), _env.ep().rpc_ep(), *this };
/* queue a child reload from the async Parent interface */
Signal_transmitter _exit_transmitter;
bool _have_config = _start_node.has_sub_node("config");
Child(Genode::Env &env,
Xml_node const &start_node,
Signal_context_capability exit_handler)
:
_env(env),
_start_node(start_node),
_exit_transmitter(exit_handler)
{
if (_have_config) {
Xml_node config_node = start_node.sub_node("config");
_config_policy.load(config_node.addr(), config_node.size());
}
}
~Child()
{
_parent_services.for_each([&] (Parent_service &service) {
destroy(_services_heap, &service); });
}
/****************************
** Child_policy interface **
****************************/
Name name() const override { return _name; }
Binary_name binary_name() const override { return _binary_name; }
/**
* Provide a "config" ROM if configured to do so,
* otherwise forward directly to the parent.
*/
Service &resolve_session_request(Service::Name const &name,
Session_state::Args const &args)
{
if (_have_config) {
Service *s = _config_policy.resolve_session_request(
name.string(), args.string());
if (s)
return *s;
}
return *new (_services_heap) Parent_service(_parent_services, _env, name);
}
/**
* Only a single child is managed at a time so
* no additional PD management is required.
*/
Pd_session &ref_pd() override { return _env.pd(); }
Pd_session_capability ref_pd_cap() const override { return _env.pd_session_cap(); }
/**
* If the exit is successful then queue a child reload via a signal,
* otherwise exit this parent component.
*/
void exit(int exit_value) override
{
if (exit_value == 0)
_exit_transmitter.submit();
else {
error("child \"", name(), "\" exited with exit value ", exit_value);
_env.parent().exit(exit_value);
sleep_forever();
}
}
/**
* TODO: respond to yield_response by withdrawing
* child quota and informing our parent.
*/
/**
* Upgrade child quotas from our quotas,
* otherwise request more quota from our parent.
*/
void resource_request(Parent::Resource_args const &args) override
{
Ram_quota ram = ram_quota_from_args(args.string());
Cap_quota caps = cap_quota_from_args(args.string());
Pd_session_capability pd_cap = _child.pd_session_cap();
/* XXX: pretty simplistic math here */
if (ram.value) {
Ram_quota avail = _env.pd().avail_ram();
if (avail.value > ram.value) {
ref_pd().transfer_quota(pd_cap, ram);
} else {
ref_pd().transfer_quota(pd_cap, Ram_quota{avail.value >> 1});
_env.parent().resource_request(args);
}
}
if (caps.value) {
Cap_quota avail = _env.pd().avail_caps();
if (avail.value > caps.value) {
ref_pd().transfer_quota(pd_cap, caps);
} else {
ref_pd().transfer_quota(pd_cap, Cap_quota{avail.value >> 1});
_env.parent().resource_request(args);
}
}
_child.notify_resource_avail();
}
/**
* Initialize the child Protection Domain session with half of
* the initial quotas of this parent component.
*/
void init(Pd_session &pd, Pd_session_capability pd_cap) override
{
pd.ref_account(ref_pd_cap());
ref_pd().transfer_quota(pd_cap, Cap_quota{_env.pd().avail_caps().value >> 1});
ref_pd().transfer_quota(pd_cap, Ram_quota{_env.pd().avail_ram().value >> 1});
}
};
struct Sequence::Main
{
Genode::Env &env;
Constructible<Sequence::Child> child;
Attached_rom_dataspace config_rom { env, "config" };
Xml_node const config_xml = config_rom.xml();
int next_xml_index = 0;
void start_next_child();
Signal_handler<Main> exit_handler {
env.ep(), *this, &Main::start_next_child };
Main(Genode::Env &e) : env(e) {
start_next_child(); }
};
void Sequence::Main::start_next_child()
{
if (child.constructed())
child.destruct();
try { while (true) {
Xml_node sub_node = config_xml.sub_node(next_xml_index++);
if (sub_node.type() != "start")
continue;
child.construct(env, sub_node, exit_handler);
break;
} }
catch (Xml_node::Nonexistent_sub_node) {
env.parent().exit(0); }
}
void Component::construct(Genode::Env &env) {
static Sequence::Main main(env); }

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TARGET = sequence
SRC_CC = main.cc
LIBS = base