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eaac3cc1bd
This patch curates the API documentation to become suitable for the functional specificaton, which is partially generated from the header files.
314 lines
8.1 KiB
C++
314 lines
8.1 KiB
C++
/*
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* \brief Child handling
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* \author Norman Feske
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* \date 2013-10-05
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*/
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/*
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* Copyright (C) 2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _INCLUDE__CLI_MONITOR__CHILD_H_
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#define _INCLUDE__CLI_MONITOR__CHILD_H_
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/* Genode includes */
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#include <util/list.h>
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#include <base/child.h>
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#include <init/child_policy.h>
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#include <os/child_policy_dynamic_rom.h>
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#include <cpu_session/connection.h>
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/* CLI-monitor includes */
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#include <cli_monitor/ram.h>
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class Child_base : public Genode::Child_policy
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{
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public:
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/*
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* XXX derive donated quota from information to be provided by
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* the used 'Connection' interfaces
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*/
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enum { DONATED_RAM_QUOTA = 128*1024 };
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class Quota_exceeded : public Genode::Exception { };
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typedef Genode::String<128> Label;
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typedef Genode::size_t size_t;
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private:
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Ram &_ram;
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Label const _label;
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struct Resources
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{
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Genode::Ram_connection ram;
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Genode::Cpu_connection cpu;
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Genode::Rm_connection rm;
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Resources(const char *label, Genode::size_t ram_quota)
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: ram(label), cpu(label)
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{
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if (ram_quota > DONATED_RAM_QUOTA)
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ram_quota -= DONATED_RAM_QUOTA;
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else
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throw Quota_exceeded();
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ram.ref_account(Genode::env()->ram_session_cap());
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if (Genode::env()->ram_session()->transfer_quota(ram.cap(), ram_quota) != 0)
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throw Quota_exceeded();
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}
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};
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size_t _ram_quota;
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size_t _ram_limit;
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Resources _resources;
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Genode::Service_registry _parent_services;
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Genode::Rom_connection _binary_rom;
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enum { ENTRYPOINT_STACK_SIZE = 12*1024 };
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Genode::Rpc_entrypoint _entrypoint;
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Init::Child_policy_enforce_labeling _labeling_policy;
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Init::Child_policy_provide_rom_file _binary_policy;
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Genode::Child_policy_dynamic_rom_file _config_policy;
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Genode::Child _child;
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/**
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* If set to true, immediately withdraw resources yielded by the child
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*/
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bool _withdraw_on_yield_response = false;
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/**
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* Arguments of current resource request from the child
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*/
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Genode::Parent::Resource_args _resource_args;
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Genode::Signal_context_capability _yield_response_sigh_cap;
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public:
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Child_base(Ram &ram,
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char const *label,
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char const *binary,
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Genode::Cap_session &cap_session,
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Genode::size_t ram_quota,
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Genode::size_t ram_limit,
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Genode::Signal_context_capability yield_response_sig_cap)
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:
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_ram(ram),
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_label(label),
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_ram_quota(ram_quota),
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_ram_limit(ram_limit),
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_resources(_label.string(), _ram_quota),
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_binary_rom(binary, _label.string()),
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_entrypoint(&cap_session, ENTRYPOINT_STACK_SIZE, _label.string(), false),
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_labeling_policy(_label.string()),
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_binary_policy("binary", _binary_rom.dataspace(), &_entrypoint),
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_config_policy("config", _entrypoint, &_resources.ram),
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_child(_binary_rom.dataspace(),
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_resources.ram.cap(), _resources.cpu.cap(),
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_resources.rm.cap(), &_entrypoint, this),
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_yield_response_sigh_cap(yield_response_sig_cap)
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{ }
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Label label() const { return _label; }
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void configure(char const *config, size_t config_len)
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{
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_config_policy.load(config, config_len);
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}
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void start()
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{
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_entrypoint.activate();
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}
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/**
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* Issue yield request to the child
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*/
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void yield(size_t amount, bool greedy)
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{
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if (requested_ram_quota())
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return; /* resource request in flight */
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char buf[128];
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Genode::snprintf(buf, sizeof(buf), "ram_quota=%zd", amount);
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_withdraw_on_yield_response = greedy;
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_child.yield(buf);
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}
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/**
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* Return amount of RAM currently requested by the child
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*/
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size_t requested_ram_quota() const
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{
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return Genode::Arg_string::find_arg(_resource_args.string(), "ram_quota").ulong_value(0);
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}
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/**
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* Withdraw quota from the child
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*
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* \throw Ram::Transfer_quota_failed
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*/
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void withdraw_ram_quota(size_t amount)
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{
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if (!amount)
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return;
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_ram.withdraw_from(_resources.ram.cap(), amount);
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_ram_quota -= amount;
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}
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/**
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* Upgrade quota of child
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*
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* \throw Ram::Transfer_quota_failed
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*/
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void upgrade_ram_quota(size_t amount)
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{
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_ram.transfer_to(_resources.ram.cap(), amount);
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_ram_quota += amount;
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/* wake up child if resource request is in flight */
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size_t const req = requested_ram_quota();
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if (req && _resources.ram.avail() >= req) {
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_child.notify_resource_avail();
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/* clear request state */
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_resource_args = Genode::Parent::Resource_args("");
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}
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}
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/**
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* Try to respond to a current resource request issued by the child
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*
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* This method evaluates the conditions, under which a resource
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* request can be answered: There must be enough room between the
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* current quota and the configured limit, and there must be enough
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* slack memory available. If both conditions are met, the quota
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* of the child gets upgraded.
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*/
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void try_response_to_resource_request()
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{
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size_t const req = requested_ram_quota();
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if (!req)
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return; /* no resource request in flight */
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/*
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* Respond to the current request if the requested quota fits
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* within the limit and if there is enough free quota available.
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*/
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if (req <= _ram.status().avail && req + _ram_quota <= _ram_limit) {
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try { upgrade_ram_quota(req); }
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catch (Ram::Transfer_quota_failed) { }
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}
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}
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/**
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* Set limit for on-demand RAM quota expansion
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*/
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void ram_limit(size_t limit)
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{
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_ram_limit = limit;
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try_response_to_resource_request();
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}
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struct Ram_status
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{
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size_t quota = 0, limit = 0, xfer = 0, used = 0, avail = 0, req = 0;
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Ram_status() { }
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Ram_status(size_t quota, size_t limit, size_t xfer, size_t used,
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size_t avail, size_t req)
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:
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quota(quota), limit(limit), xfer(xfer), used(used),
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avail(avail), req(req)
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{ }
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};
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/**
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* Return RAM quota status of the child
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*
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* XXX should be a const method, but the 'Ram_session' accessors
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* are not const
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*/
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Ram_status ram_status()
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{
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return Ram_status(_ram_quota,
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_ram_limit,
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_ram_quota - _resources.ram.quota(),
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_resources.ram.used(),
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_resources.ram.avail(),
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requested_ram_quota());
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}
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/****************************
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** Child_policy interface **
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****************************/
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const char *name() const { return _label.string(); }
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Genode::Service *resolve_session_request(const char *service_name,
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const char *args)
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{
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Genode::Service *service = 0;
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/* check for binary file request */
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if ((service = _binary_policy.resolve_session_request(service_name, args)))
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return service;
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/* check for config file request */
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if ((service = _config_policy.resolve_session_request(service_name, args)))
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return service;
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/* fill parent service registry on demand */
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if (!(service = _parent_services.find(service_name))) {
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service = new (Genode::env()->heap())
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Genode::Parent_service(service_name);
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_parent_services.insert(service);
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}
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/* return parent service */
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return service;
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}
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void filter_session_args(const char *service,
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char *args, Genode::size_t args_len)
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{
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_labeling_policy.filter_session_args(service, args, args_len);
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}
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void yield_response()
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{
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if (_withdraw_on_yield_response) {
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enum { RESERVE = 4*1024*1024 };
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size_t amount = _resources.ram.avail() < RESERVE
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? 0 : _resources.ram.avail() - RESERVE;
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/* try to immediately withdraw freed-up resources */
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try { withdraw_ram_quota(amount); }
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catch (Ram::Transfer_quota_failed) { }
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}
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/* propagate yield-response signal */
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Genode::Signal_transmitter(_yield_response_sigh_cap).submit();
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}
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void resource_request(Genode::Parent::Resource_args const &args)
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{
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_resource_args = args;
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try_response_to_resource_request();
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}
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};
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#endif /* _INCLUDE__CLI_MONITOR__CHILD_H_ */
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