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genode/base-linux/include/base/platform_env.h
Norman Feske 693d657e6a base-linux: reflect SIGCHLD as Cpu_session signal 
With this patch, core responds to SIGCHLD signals of terminating Genode
processes by reflecting these events as exceptions to the CPU session
interface. This way, Genode processes become able to respond to
terminating Genode child processes.
2013-01-04 15:26:16 +01:00

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/*
* \brief Linux-specific environment
* \author Norman Feske
* \author Christian Helmuth
* \date 2006-07-28
*/
/*
* Copyright (C) 2006-2012 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__BASE__PLATFORM_ENV_H_
#define _INCLUDE__BASE__PLATFORM_ENV_H_
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <base/env.h>
#include <base/printf.h>
#include <util/misc_math.h>
#include <base/heap.h>
#include <parent/client.h>
#include <ram_session/client.h>
#include <linux_cpu_session/client.h>
#include <pd_session/client.h>
namespace Genode {
/**
* Common base class of the 'Platform_env' implementations for core and
* non-core processes.
*/
class Platform_env_base : public Env
{
private:
/**************************
** Local region manager **
**************************/
class Region
{
private:
addr_t _start;
off_t _offset;
Dataspace_capability _ds;
size_t _size;
/**
* Return offset of first byte after the region
*/
addr_t _end() const { return _start + _size; }
public:
Region() : _start(0), _offset(0), _size(0) { }
Region(addr_t start, off_t offset, Dataspace_capability ds, size_t size)
: _start(start), _offset(offset), _ds(ds), _size(size) { }
bool used() const { return _size > 0; }
addr_t start() const { return _start; }
off_t offset() const { return _offset; }
size_t size() const { return _size; }
Dataspace_capability dataspace() const { return _ds; }
bool intersects(Region const &r) const
{
return (r.start() < _end()) && (_start < r._end());
}
};
/**
* Meta data about dataspaces attached to an RM session
*/
class Region_map
{
public:
enum { MAX_REGIONS = 4096 };
private:
Region _map[MAX_REGIONS];
bool _id_valid(int id) const {
return (id >= 0 && id < MAX_REGIONS); }
public:
/**
* Add region to region map
*
* \return region ID, or
* -1 if out of metadata, or
* -2 if region conflicts existing region
*/
int add_region(Region const &region)
{
/*
* Check for region conflicts
*/
for (int i = 0; i < MAX_REGIONS; i++) {
if (_map[i].intersects(region))
return -2;
}
/*
* Allocate new region metadata
*/
int i;
for (i = 0; i < MAX_REGIONS; i++)
if (!_map[i].used()) break;
if (i == MAX_REGIONS) {
PERR("maximum number of %d regions reached",
MAX_REGIONS);
return -1;
}
_map[i] = region;
return i;
}
Region region(int id) const
{
return _id_valid(id) ? _map[id] : Region();
}
Region lookup(addr_t start)
{
for (int i = 0; i < MAX_REGIONS; i++)
if (_map[i].start() == start)
return _map[i];
return Region();
}
void remove_region(addr_t start)
{
for (int i = 0; i < MAX_REGIONS; i++)
if (_map[i].start() == start)
_map[i] = Region();
}
};
protected:
/*
* 'Rm_session_mmap' is 'protected' because it is instantiated by
* 'Platform_env::Local_parent::session()'.
*/
/*
* On Linux, we use a local region manager session that attaches
* dataspaces via mmap to the local address space.
*/
class Rm_session_mmap : public Rm_session,
public Dataspace
{
private:
Lock _lock; /* protect '_rmap' */
Region_map _rmap;
bool const _sub_rm; /* false if RM session is root */
size_t const _size;
/**
* Base offset of the RM session
*
* For a normal RM session (the one that comes with the
* 'env()', this value is zero. If the RM session is
* used as nested dataspace, '_base' contains the address
* where the managed dataspace is attached in the root RM
* session.
*
* Note that a managed dataspace cannot be attached more
* than once. Furthermore, managed dataspace cannot be
* attached to another managed dataspace. The nested
* dataspace emulation is solely implemented to support
* the common use case of managed dataspaces as mechanism
* to reserve parts of the local address space from being
* populated by the 'env()->rm_session()'. (i.e., for the
* context area, or for the placement of consecutive
* shared-library segments)
*/
addr_t _base;
bool _is_attached() const { return _base > 0; }
void _add_to_rmap(Region const &);
/**
* Map dataspace into local address space
*/
void *_map_local(Dataspace_capability ds,
Genode::size_t size,
addr_t offset,
bool use_local_addr,
addr_t local_addr,
bool executable);
/**
* Determine size of dataspace
*
* For core, this function performs a local lookup of the
* 'Dataspace_component' object. For non-core programs, the
* dataspace size is determined via an RPC to core
* (calling 'Dataspace::size()').
*/
size_t _dataspace_size(Capability<Dataspace>);
/**
* Determine file descriptor of dataspace
*/
int _dataspace_fd(Capability<Dataspace>);
/**
* Determine whether dataspace is writable
*/
bool _dataspace_writable(Capability<Dataspace>);
public:
Rm_session_mmap(bool sub_rm, size_t size = ~0)
: _sub_rm(sub_rm), _size(size), _base(0) { }
~Rm_session_mmap()
{
/* detach sub RM session when destructed */
if (_sub_rm && _is_attached())
env()->rm_session()->detach((void *)_base);
}
/**************************************
** Region manager session interface **
**************************************/
Local_addr attach(Dataspace_capability ds, size_t size,
off_t, bool, Local_addr,
bool executable);
void detach(Local_addr local_addr);
Pager_capability add_client(Thread_capability thread) {
return Pager_capability(); }
void fault_handler(Signal_context_capability handler) { }
State state() { return State(); }
/*************************
** Dataspace interface **
*************************/
size_t size() { return _size; }
addr_t phys_addr() { return 0; }
bool writable() { return true; }
/**
* Return pseudo dataspace capability of the RM session
*
* The capability returned by this function is only usable
* as argument to 'Rm_session_mmap::attach'. It is not a
* real capability.
*/
Dataspace_capability dataspace()
{
return Dataspace_capability::local_cap(this);
}
};
private:
class Expanding_ram_session_client : public Ram_session_client
{
Ram_session_capability _cap;
public:
Expanding_ram_session_client(Ram_session_capability cap)
: Ram_session_client(cap), _cap(cap) { }
Ram_dataspace_capability alloc(size_t size, bool cached) {
bool try_again;
do {
try_again = false;
try {
return Ram_session_client::alloc(size, cached);
} catch (Ram_session::Out_of_metadata) {
/* give up if the error occurred a second time */
if (try_again)
break;
PINF("upgrading quota donation for Env::RAM session");
env()->parent()->upgrade(_cap, "ram_quota=8K");
try_again = true;
}
} while (try_again);
return Ram_dataspace_capability();
}
};
/*******************************
** Platform-specific members **
*******************************/
Ram_session_capability _ram_session_cap;
Expanding_ram_session_client _ram_session_client;
Cpu_session_capability _cpu_session_cap;
Linux_cpu_session_client _cpu_session_client;
Rm_session_mmap _rm_session_mmap;
Pd_session_client _pd_session_client;
public:
/**
* Constructor
*/
Platform_env_base(Ram_session_capability ram_cap,
Cpu_session_capability cpu_cap,
Pd_session_capability pd_cap)
:
_ram_session_cap(ram_cap),
_ram_session_client(_ram_session_cap),
_cpu_session_cap(cpu_cap),
_cpu_session_client(static_cap_cast<Linux_cpu_session>(cpu_cap)),
_rm_session_mmap(false),
_pd_session_client(pd_cap)
{ }
/*******************
** Env interface **
*******************/
Ram_session *ram_session() { return &_ram_session_client; }
Ram_session_capability ram_session_cap() { return _ram_session_cap; }
Rm_session *rm_session() { return &_rm_session_mmap; }
Linux_cpu_session *cpu_session() { return &_cpu_session_client; }
Cpu_session_capability cpu_session_cap() { return _cpu_session_cap; }
Pd_session *pd_session() { return &_pd_session_client; }
};
/**
* 'Platform_env' used by all processes except for core
*/
class Platform_env : public Platform_env_base
{
private:
/**
* Local interceptor of parent requests
*
* On Linux, we need to intercept calls to the parent interface to
* implement the RM service locally. This particular service is
* used for creating managed dataspaces, which allow the
* reservation of parts of the local address space from being
* automatically managed by the 'env()->rm_session()'.
*
* All requests that do not refer to the RM service are passed
* through the real parent interface.
*/
class Local_parent : public Parent_client
{
public:
/**********************
** Parent interface **
**********************/
Session_capability session(Service_name const &,
Session_args const &);
void close(Session_capability);
/**
* Constructor
*
* \param parent_cap real parent capability used to
* promote requests to non-local
* services
*/
Local_parent(Parent_capability parent_cap);
};
/**
* Obtain singleton instance of parent interface
*/
static Local_parent &_parent();
Heap _heap;
/*************************************
** Linux-specific helper functions **
*************************************/
public:
/**
* Constructor
*/
Platform_env();
/**
* Destructor
*/
~Platform_env() { _parent().exit(0); }
/**
* Reload parent capability and reinitialize environment resources
*/
void reload_parent_cap(Capability<Parent>::Dst, long)
{
/* not supported on Linux */
}
/*******************
** Env interface **
*******************/
Parent *parent() { return &_parent(); }
Heap *heap() { return &_heap; }
};
}
#endif /* _INCLUDE__BASE__PLATFORM_ENV_H_ */
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