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genode/repos/ports/src/noux/child.h

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/*
* \brief Noux child process
* \author Norman Feske
* \date 2011-02-17
*/
/*
* Copyright (C) 2011-2013 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 _NOUX__CHILD_H_
#define _NOUX__CHILD_H_
/* Genode includes */
#include <base/signal.h>
#include <base/semaphore.h>
#include <cap_session/cap_session.h>
#include <pd_session/connection.h>
#include <os/attached_ram_dataspace.h>
/* Noux includes */
#include <file_descriptor_registry.h>
#include <vfs/dir_file_system.h>
#include <noux_session/capability.h>
#include <args.h>
#include <environment.h>
#include <ram_session_component.h>
#include <cpu_session_component.h>
#include <child_policy.h>
#include <io_receptor_registry.h>
#include <destruct_queue.h>
#include <destruct_dispatcher.h>
#include <interrupt_handler.h>
#include <kill_broadcaster.h>
#include <parent_execve.h>
#include <local_cpu_service.h>
#include <local_rom_service.h>
namespace Noux {
/**
* Allocator for process IDs
*/
class Pid_allocator
{
private:
Lock _lock;
int _num_pids;
public:
Pid_allocator() : _num_pids(0) { }
int alloc()
{
Lock::Guard guard(_lock);
return _num_pids++;
}
};
/**
* Return singleton instance of PID allocator
*/
Pid_allocator *pid_allocator();
/**
* Return singleton instance of timeout scheduler
*/
class Timeout_scheduler;
Timeout_scheduler *timeout_scheduler();
/**
* Return singleton instance of user information
*/
class User_info;
User_info *user_info();
/**
* Return singleton instance of Io_receptor_registry
*/
Io_receptor_registry *io_receptor_registry();
/**
* Return ELF binary of dynamic linker
*/
Dataspace_capability ldso_ds_cap();
/*
* Return lock for protecting the signal queue
*/
Genode::Lock &signal_lock();
class Child;
bool is_init_process(Child *child);
void init_process_exited(int);
class Child : public Rpc_object<Session>,
public File_descriptor_registry,
public Family_member,
public Destruct_queue::Element<Child>,
public Interrupt_handler
{
private:
Parent_exit *_parent_exit;
Kill_broadcaster &_kill_broadcaster;
Parent_execve &_parent_execve;
Signal_receiver *_sig_rec;
Allocator *_alloc;
Destruct_queue &_destruct_queue;
Destruct_dispatcher _destruct_dispatcher;
Signal_context_capability _destruct_context_cap;
Cap_session * const _cap_session;
enum { STACK_SIZE = 4*1024*sizeof(long) };
Rpc_entrypoint _entrypoint;
Pd_connection _pd;
/**
* Resources assigned to the child
*/
struct Resources
{
/**
* Entrypoint used to serve the RPC interfaces of the
* locally-provided services
*/
Rpc_entrypoint &ep;
/**
* Registry of dataspaces owned by the Noux process
*/
Dataspace_registry ds_registry;
/**
* Locally-provided services for accessing platform resources
*/
Ram_session_component ram;
Cpu_session_component cpu;
Rm_session_component rm;
Resources(char const *label, Rpc_entrypoint &ep, bool forked)
:
ep(ep), ram(ds_registry), cpu(label, forked), rm(ds_registry)
{
ep.manage(&ram);
ep.manage(&rm);
ep.manage(&cpu);
}
~Resources()
{
ep.dissolve(&ram);
ep.dissolve(&rm);
ep.dissolve(&cpu);
}
} _resources;
/**
* Command line arguments
*/
Args_dataspace _args;
/**
* Environment variables
*/
Environment _env;
/**
* ELF binary handling
*/
struct Elf
{
enum { NAME_MAX_LEN = 128 };
char _name[NAME_MAX_LEN];
Vfs::Dir_file_system * const _root_dir;
Dataspace_capability const _binary_ds;
Elf(char const * const binary_name, Vfs::Dir_file_system * root_dir,
Dataspace_capability binary_ds)
:
_root_dir(root_dir), _binary_ds(binary_ds)
{
strncpy(_name, binary_name, sizeof(_name));
_name[NAME_MAX_LEN - 1] = 0;
}
~Elf() { _root_dir->release(_name, _binary_ds); }
} _elf;
enum { PAGE_SIZE = 4096, PAGE_MASK = ~(PAGE_SIZE - 1) };
enum { SYSIO_DS_SIZE = PAGE_MASK & (sizeof(Sysio) + PAGE_SIZE - 1) };
Attached_ram_dataspace _sysio_ds;
Sysio * const _sysio;
typedef Ring_buffer<enum Sysio::Signal, Sysio::SIGNAL_QUEUE_SIZE>
Signal_queue;
Signal_queue _pending_signals;
Session_capability const _noux_session_cap;
Local_noux_service _local_noux_service;
Parent_service _parent_ram_service;
Local_cpu_service _local_cpu_service;
Local_rm_service _local_rm_service;
Local_rom_service _local_rom_service;
Service_registry &_parent_services;
Static_dataspace_info _binary_ds_info;
Static_dataspace_info _sysio_ds_info;
Static_dataspace_info _ldso_ds_info;
Static_dataspace_info _args_ds_info;
Static_dataspace_info _env_ds_info;
Child_policy _child_policy;
Genode::Child _child;
/**
* Exception type for failed file-descriptor lookup
*/
class Invalid_fd { };
Shared_pointer<Io_channel> _lookup_channel(int fd) const
{
Shared_pointer<Io_channel> channel = io_channel_by_fd(fd);
if (channel)
return channel;
throw Invalid_fd();
}
enum { ARGS_DS_SIZE = 4096 };
/**
* Let specified child inherit our file descriptors
*/
void _assign_io_channels_to(Child *child)
{
for (int fd = 0; fd < MAX_FILE_DESCRIPTORS; fd++)
if (fd_in_use(fd))
child->add_io_channel(io_channel_by_fd(fd), fd);
}
/**
* Block until the IO channel is ready for reading or writing or an
* exception occured.
*
* \param io the IO channel
* \param rd check for data available for reading
* \param wr check for readiness for writing
* \param ex check for exceptions
*/
void _block_for_io_channel(Shared_pointer<Io_channel> &io,
bool rd, bool wr, bool ex)
{
/* reset the blocker lock to the 'locked' state */
_blocker.unlock();
_blocker.lock();
Wake_up_notifier notifier(&_blocker);
io->register_wake_up_notifier(&notifier);
for (;;) {
if (io->check_unblock(rd, wr, ex) ||
!_pending_signals.empty())
break;
/* block (unless the lock got unlocked in the meantime) */
_blocker.lock();
}
io->unregister_wake_up_notifier(&notifier);
}
Vfs::Dir_file_system * const root_dir() { return _elf._root_dir; }
/**
* Method for handling noux network related system calls
*/
bool _syscall_net(Syscall sc);
void _destruct() {
_sig_rec->dissolve(&_destruct_dispatcher);
_entrypoint.dissolve(this);
if (is_init_process(this))
init_process_exited(_child_policy.exit_value());
}
public:
struct Binary_does_not_exist : Exception { };
struct Insufficient_memory : Exception { };
/**
* Constructor
*
* \param forked false if the child is spawned directly from
* an executable binary (i.e., the init process,
* or children created via execve, or
* true if the child is a fork from another child
*
* \throw Binary_does_not_exist if child is not a fork and the
* specified name could not be
* looked up at the virtual file
* system
* \throw Insufficent_memory if the child could not be started by
* the parent
*/
Child(char const *binary_name,
Parent_exit *parent_exit,
Kill_broadcaster &kill_broadcaster,
Parent_execve &parent_execve,
int pid,
Signal_receiver *sig_rec,
Vfs::Dir_file_system *root_dir,
Args const &args,
Sysio::Env const &env,
Cap_session *cap_session,
Service_registry &parent_services,
Rpc_entrypoint &resources_ep,
bool forked,
Allocator *destruct_alloc,
Destruct_queue &destruct_queue,
bool verbose)
:
Family_member(pid),
Destruct_queue::Element<Child>(destruct_alloc),
_parent_exit(parent_exit),
_kill_broadcaster(kill_broadcaster),
_parent_execve(parent_execve),
_sig_rec(sig_rec),
_destruct_queue(destruct_queue),
_destruct_dispatcher(_destruct_queue, this),
_destruct_context_cap(sig_rec->manage(&_destruct_dispatcher)),
_cap_session(cap_session),
_entrypoint(cap_session, STACK_SIZE, "noux_process", false),
_pd(binary_name),
_resources(binary_name, resources_ep, false),
_args(ARGS_DS_SIZE, args),
_env(env),
_elf(binary_name, root_dir, root_dir->dataspace(binary_name)),
_sysio_ds(Genode::env()->ram_session(), SYSIO_DS_SIZE),
_sysio(_sysio_ds.local_addr<Sysio>()),
_noux_session_cap(Session_capability(_entrypoint.manage(this))),
_local_noux_service(_noux_session_cap),
_parent_ram_service(""),
_local_cpu_service(_entrypoint, _resources.cpu.cpu_cap()),
_local_rm_service(_entrypoint, _resources.ds_registry),
_local_rom_service(_entrypoint, _resources.ds_registry),
_parent_services(parent_services),
_binary_ds_info(_resources.ds_registry, _elf._binary_ds),
_sysio_ds_info(_resources.ds_registry, _sysio_ds.cap()),
_ldso_ds_info(_resources.ds_registry, ldso_ds_cap()),
_args_ds_info(_resources.ds_registry, _args.cap()),
_env_ds_info(_resources.ds_registry, _env.cap()),
_child_policy(_elf._name, _elf._binary_ds, _args.cap(), _env.cap(),
_entrypoint, _local_noux_service,
_local_rm_service, _local_rom_service,
_parent_services,
*this, parent_exit, *this, _destruct_context_cap,
_resources.ram, verbose),
_child(forked ? Dataspace_capability() : _elf._binary_ds,
_pd.cap(), _resources.ram.cap(), _resources.cpu.cap(),
_resources.rm.cap(), &_entrypoint, &_child_policy,
_parent_ram_service, _local_cpu_service, _local_rm_service)
{
if (verbose)
_args.dump();
if (!forked && !_elf._binary_ds.valid()) {
PERR("Lookup of executable \"%s\" failed", binary_name);
_destruct();
throw Binary_does_not_exist();
}
if (!_child.main_thread_cap().valid()) {
_destruct();
throw Insufficient_memory();
}
}
~Child() { _destruct(); }
void start() { _entrypoint.activate(); }
void start_forked_main_thread(addr_t ip, addr_t sp, addr_t parent_cap_addr)
{
/* poke parent_cap_addr into child's address space */
Capability<Parent> const &cap = _child.parent_cap();
Capability<Parent>::Raw raw = { cap.dst(), cap.local_name() };
_resources.rm.poke(parent_cap_addr, &raw, sizeof(raw));
/* start execution of new main thread at supplied trampoline */
_resources.cpu.start_main_thread(ip, sp);
}
void submit_exit_signal()
{
if (is_init_process(this)) {
PINF("init process exited");
/* trigger exit of main event loop */
init_process_exited(_child_policy.exit_value());
} else {
Signal_transmitter(_destruct_context_cap).submit();
}
}
Ram_session_capability ram() const { return _resources.ram.cap(); }
Rm_session_capability rm() const { return _resources.rm.cap(); }
Dataspace_registry &ds_registry() { return _resources.ds_registry; }
/****************************
** Noux session interface **
****************************/
Dataspace_capability sysio_dataspace()
{
return _sysio_ds.cap();
}
Rm_session_capability lookup_rm_session(addr_t const addr)
{
return _resources.rm.lookup_rm_session(addr);
}
bool syscall(Syscall sc);
int next_open_fd(int start_fd)
{
if (start_fd >= 0)
for (int fd = start_fd; fd < MAX_FILE_DESCRIPTORS; fd++)
if (fd_in_use(fd))
return fd;
return -1;
}
/****************************************
** File_descriptor_registry overrides **
****************************************/
/**
* Find out if the IO channel associated with 'fd' has more file
* descriptors associated with it
*/
bool _is_the_only_fd_for_io_channel(int fd,
Shared_pointer<Io_channel> io_channel)
{
for (int f = 0; f < MAX_FILE_DESCRIPTORS; f++) {
if ((f != fd) &&
fd_in_use(f) &&
(io_channel_by_fd(f) == io_channel))
return false;
}
return true;
}
int add_io_channel(Shared_pointer<Io_channel> io_channel, int fd = -1)
{
fd = File_descriptor_registry::add_io_channel(io_channel, fd);
/* Register the interrupt handler only once per IO channel */
if (_is_the_only_fd_for_io_channel(fd, io_channel)) {
Io_channel_listener *l = new (env()->heap()) Io_channel_listener(this);
io_channel->register_interrupt_handler(l);
}
return fd;
}
void remove_io_channel(int fd)
{
Shared_pointer<Io_channel> io_channel = _lookup_channel(fd);
/*
* Unregister the interrupt handler only if there are no other
* file descriptors associated with the IO channel.
*/
if (_is_the_only_fd_for_io_channel(fd, io_channel)) {
Io_channel_listener *l = io_channel->lookup_io_channel_listener(this);
io_channel->unregister_interrupt_handler(l);
Genode::destroy(env()->heap(), l);
}
File_descriptor_registry::remove_io_channel(fd);
}
void flush()
{
for (int fd = 0; fd < MAX_FILE_DESCRIPTORS; fd++)
try {
remove_io_channel(fd);
} catch (Invalid_fd) { }
}
/*****************************
** Family_member interface **
*****************************/
void submit_signal(Noux::Sysio::Signal sig)
{
try {
_pending_signals.add(sig);
} catch (Signal_queue::Overflow) {
PERR("signal queue is full - signal dropped");
}
_blocker.unlock();
}
Family_member *do_execve(const char *filename,
Args const &args,
Sysio::Env const &env,
bool verbose)
{
Lock::Guard signal_lock_guard(signal_lock());
Child *child = new Child(filename,
_parent_exit,
_kill_broadcaster,
_parent_execve,
pid(),
_sig_rec,
root_dir(),
args,
env,
_cap_session,
_parent_services,
_resources.ep,
false,
Genode::env()->heap(),
_destruct_queue,
verbose);
_assign_io_channels_to(child);
/* move the signal queue */
while (!_pending_signals.empty())
child->_pending_signals.add(_pending_signals.get());
/*
* Close all open files.
*
* This action is not part of the child destructor,
* because in the case that a child exits itself,
* it may need to close all files to unblock the
* parent (which might be reading from a pipe) before
* the parent can destroy the child object.
*/
flush();
/* signal main thread to remove ourself */
Genode::Signal_transmitter(_destruct_context_cap).submit();
/* start executing the new process */
child->start();
/* this child will be removed by the execve_finalization_dispatcher */
return child;
}
/*********************************
** Interrupt_handler interface **
*********************************/
void handle_interrupt()
{
submit_signal(Sysio::SIG_INT);
}
};
};
#endif /* _NOUX__CHILD_H_ */
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