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genode/ports/src/noux/main.cc

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/*
* \brief Unix emulation environment for Genode
* \author Norman Feske
* \date 2011-02-14
*/
/*
* 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.
*/
/* Genode includes */
#include <cap_session/connection.h>
#include <os/config.h>
#include <os/alarm.h>
#include <timer_session/connection.h>
/* Noux includes */
#include <child.h>
#include <child_env.h>
#include <noux_session/sysio.h>
#include <vfs_io_channel.h>
#include <terminal_io_channel.h>
#include <dummy_input_io_channel.h>
#include <pipe_io_channel.h>
#include <dir_file_system.h>
#include <user_info.h>
#include <io_receptor_registry.h>
#include <destruct_queue.h>
static bool trace_syscalls = false;
static bool verbose_quota = false;
namespace Noux {
static Noux::Child *init_child;
bool is_init_process(Child *child) { return child == init_child; }
void init_process_exited() { init_child = 0; }
};
extern void init_network();
/**
* Timeout thread for SYSCALL_SELECT
*/
namespace Noux {
using namespace Genode;
class Timeout_scheduler : Thread<4096>, public Alarm_scheduler
{
private:
Timer::Connection _timer;
Alarm::Time _curr_time;
enum { TIMER_GRANULARITY_MSEC = 10 };
void entry()
{
for (;;) {
_timer.msleep(TIMER_GRANULARITY_MSEC);
Alarm_scheduler::handle(_curr_time);
_curr_time += TIMER_GRANULARITY_MSEC;
}
}
public:
Timeout_scheduler(unsigned long curr_time) : _curr_time(curr_time) { start(); }
Alarm::Time curr_time() const { return _curr_time; }
};
struct Timeout_state
{
bool timed_out;
Timeout_state() : timed_out(false) { }
};
class Timeout_alarm : public Alarm
{
private:
Timeout_state *_state;
Semaphore *_blocker;
Timeout_scheduler *_scheduler;
public:
Timeout_alarm(Timeout_state *st, Semaphore *blocker, Timeout_scheduler *scheduler, Time timeout)
:
_state(st),
_blocker(blocker),
_scheduler(scheduler)
{
_scheduler->schedule_absolute(this, _scheduler->curr_time() + timeout);
_state->timed_out = false;
}
void discard() { _scheduler->discard(this); }
protected:
bool on_alarm()
{
_state->timed_out = true;
_blocker->up();
return false;
}
};
};
/*****************************
** Noux syscall dispatcher **
*****************************/
bool Noux::Child::syscall(Noux::Session::Syscall sc)
{
if (trace_syscalls)
Genode::printf("PID %d -> SYSCALL %s\n",
pid(), Noux::Session::syscall_name(sc));
try {
switch (sc) {
case SYSCALL_WRITE:
{
size_t const count_in = _sysio->write_in.count;
for (size_t count = 0; count != count_in; ) {
Shared_pointer<Io_channel> io = _lookup_channel(_sysio->write_in.fd);
if (!io->is_nonblocking())
if (!io->check_unblock(false, true, false))
_block_for_io_channel(io);
/*
* 'io->write' is expected to update 'write_out.count'
*/
if (io->write(_sysio, count) == false)
return false;
}
return true;
}
case SYSCALL_READ:
{
Shared_pointer<Io_channel> io = _lookup_channel(_sysio->read_in.fd);
if (!io->is_nonblocking())
while (!io->check_unblock(true, false, false))
_block_for_io_channel(io);
return io->read(_sysio);
}
case SYSCALL_FTRUNCATE:
{
Shared_pointer<Io_channel> io = _lookup_channel(_sysio->ftruncate_in.fd);
while (!io->check_unblock(true, false, false))
_block_for_io_channel(io);
return io->ftruncate(_sysio);
}
case SYSCALL_STAT:
case SYSCALL_LSTAT: /* XXX implement difference between 'lstat' and 'stat' */
{
bool result = _root_dir->stat(_sysio, _sysio->stat_in.path);
/**
* Instead of using the uid/gid given by the actual file system
* we use the ones specificed in the config.
*/
if (result) {
_sysio->stat_out.st.uid = user_info()->uid;
_sysio->stat_out.st.gid = user_info()->gid;
}
return result;
}
case SYSCALL_FSTAT:
return _lookup_channel(_sysio->fstat_in.fd)->fstat(_sysio);
case SYSCALL_FCNTL:
if (_sysio->fcntl_in.cmd == Sysio::FCNTL_CMD_SET_FD_FLAGS) {
/* we assume that there is only the close-on-execve flag */
_lookup_channel(_sysio->fcntl_in.fd)->close_on_execve =
!!_sysio->fcntl_in.long_arg;
return true;
}
return _lookup_channel(_sysio->fcntl_in.fd)->fcntl(_sysio);
case SYSCALL_OPEN:
{
Vfs_handle *vfs_handle = _root_dir->open(_sysio, _sysio->open_in.path);
if (!vfs_handle)
return false;
char const *leaf_path = _root_dir->leaf_path(_sysio->open_in.path);
/*
* File descriptors of opened directories are handled by
* '_root_dir'. In this case, we use the absolute path as leaf
* path because path operations always refer to the global
* root.
*/
if (vfs_handle->ds() == _root_dir)
leaf_path = _sysio->open_in.path;
Shared_pointer<Io_channel>
channel(new Vfs_io_channel(_sysio->open_in.path,
leaf_path, _root_dir, vfs_handle),
Genode::env()->heap());
_sysio->open_out.fd = add_io_channel(channel);
return true;
}
case SYSCALL_CLOSE:
{
remove_io_channel(_sysio->close_in.fd);
return true;
}
case SYSCALL_IOCTL:
return _lookup_channel(_sysio->ioctl_in.fd)->ioctl(_sysio);
case SYSCALL_LSEEK:
return _lookup_channel(_sysio->lseek_in.fd)->lseek(_sysio);
case SYSCALL_DIRENT:
return _lookup_channel(_sysio->dirent_in.fd)->dirent(_sysio);
case SYSCALL_EXECVE:
{
/*
* We have to check the dataspace twice because the binary
* could be a script that uses an interpreter which maybe
* does not exist.
*/
Dataspace_capability binary_ds =
_root_dir->dataspace(_sysio->execve_in.filename);
if (!binary_ds.valid()) {
_sysio->error.execve = Sysio::EXECVE_NONEXISTENT;
return false;
}
Child_env<sizeof(_sysio->execve_in.args)>
child_env(_sysio->execve_in.filename, binary_ds,
_sysio->execve_in.args, _sysio->execve_in.env);
_root_dir->release(_sysio->execve_in.filename, binary_ds);
binary_ds = _root_dir->dataspace(child_env.binary_name());
if (!binary_ds.valid()) {
_sysio->error.execve = Sysio::EXECVE_NONEXISTENT;
return false;
}
_root_dir->release(child_env.binary_name(), binary_ds);
try {
Child *child = new Child(child_env.binary_name(),
parent(),
pid(),
_sig_rec,
_root_dir,
child_env.args(),
child_env.env(),
_cap_session,
_parent_services,
_resources.ep,
false,
env()->heap(),
_destruct_queue);
/* replace ourself by the new child at the parent */
parent()->remove(this);
parent()->insert(child);
_assign_io_channels_to(child);
/* 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 true;
}
catch (Child::Binary_does_not_exist) {
_sysio->error.execve = Sysio::EXECVE_NONEXISTENT; }
return false;
}
case SYSCALL_SELECT:
{
Sysio::Select_fds &in_fds = _sysio->select_in.fds;
size_t in_fds_total = in_fds.total_fds();
int _rd_array[in_fds_total];
int _wr_array[in_fds_total];
long timeout_sec = _sysio->select_in.timeout.sec;
long timeout_usec = _sysio->select_in.timeout.usec;
bool timeout_reached = false;
/*
* Block for one action of the watched file descriptors
*/
for (;;) {
/*
* Check I/O channels of specified file descriptors for
* unblock condition. Return if one I/O channel satisfies
* the condition.
*/
size_t unblock_rd = 0;
size_t unblock_wr = 0;
size_t unblock_ex = 0;
/* process read fds */
for (Genode::size_t i = 0; i < in_fds_total; i++) {
int fd = in_fds.array[i];
if (!fd_in_use(fd)) continue;
Shared_pointer<Io_channel> io = io_channel_by_fd(fd);
if (in_fds.watch_for_rd(i))
if (io->check_unblock(true, false, false)) {
_rd_array[unblock_rd++] = fd;
}
if (in_fds.watch_for_wr(i))
if (io->check_unblock(false, true, false)) {
_wr_array[unblock_wr++] = fd;
}
if (in_fds.watch_for_ex(i))
if (io->check_unblock(false, false, true)) {
unblock_ex++;
}
}
if (unblock_rd || unblock_wr || unblock_ex) {
/**
* Merge the fd arrays in one output array
*/
for (size_t i = 0; i < unblock_rd; i++) {
_sysio->select_out.fds.array[i] = _rd_array[i];
}
_sysio->select_out.fds.num_rd = unblock_rd;
/* XXX could use a pointer to select_out.fds.array instead */
for (size_t j = unblock_rd, i = 0; i < unblock_wr; i++, j++) {
_sysio->select_out.fds.array[j] = _wr_array[i];
}
_sysio->select_out.fds.num_wr = unblock_wr;
/* exception fds are currently not considered */
_sysio->select_out.fds.num_ex = unblock_ex;
return true;
}
/*
* Return if I/O channel triggered, but timeout exceeded
*/
if (_sysio->select_in.timeout.zero() || timeout_reached) {
/*
if (timeout_reached) PINF("timeout_reached");
else PINF("timeout.zero()");
*/
_sysio->select_out.fds.num_rd = 0;
_sysio->select_out.fds.num_wr = 0;
_sysio->select_out.fds.num_ex = 0;
return true;
}
/*
* Register ourself at all watched I/O channels
*
* We instantiate as many notifiers as we have file
* descriptors to observe. Each notifier is associated
* with the child's blocking semaphore. When any of the
* notifiers get woken up, the semaphore gets unblocked.
*
* XXX However, the semaphore may get unblocked for other
* conditions such as the destruction of the child.
* ...to be done.
*/
Wake_up_notifier notifiers[in_fds_total];
for (Genode::size_t i = 0; i < in_fds_total; i++) {
int fd = in_fds.array[i];
if (!fd_in_use(fd)) continue;
Shared_pointer<Io_channel> io = io_channel_by_fd(fd);
notifiers[i].semaphore = &_blocker;
io->register_wake_up_notifier(&notifiers[i]);
}
/**
* Register ourself at the Io_receptor_registry
*
* Each entry in the registry will be unblocked if an external
* event has happend, e.g. network I/O.
*/
Io_receptor receptor(&_blocker);
io_receptor_registry()->register_receptor(&receptor);
/*
* Block at barrier except when reaching the timeout
*/
if (!_sysio->select_in.timeout.infinite()) {
unsigned long to_msec = (timeout_sec * 1000) + (timeout_usec / 1000);
Timeout_state ts;
Timeout_alarm ta(&ts, &_blocker, Noux::timeout_scheduler(), to_msec);
/* block until timeout is reached or we were unblocked */
_blocker.down();
if (ts.timed_out) {
timeout_reached = 1;
}
else {
/*
* We woke up before reaching the timeout,
* so we discard the alarm
*/
ta.discard();
}
}
else {
/* let's block infinitely */
_blocker.down();
}
/*
* Unregister barrier at watched I/O channels
*/
for (Genode::size_t i = 0; i < in_fds_total; i++) {
int fd = in_fds.array[i];
if (!fd_in_use(fd)) continue;
Shared_pointer<Io_channel> io = io_channel_by_fd(fd);
io->unregister_wake_up_notifier(&notifiers[i]);
}
/*
* Unregister receptor
*/
io_receptor_registry()->unregister_receptor(&receptor);
}
return true;
}
case SYSCALL_FORK:
{
Genode::addr_t ip = _sysio->fork_in.ip;
Genode::addr_t sp = _sysio->fork_in.sp;
Genode::addr_t parent_cap_addr = _sysio->fork_in.parent_cap_addr;
int const new_pid = pid_allocator()->alloc();
/*
* XXX To ease debugging, it would be useful to generate a
* unique name that includes the PID instead of just
* reusing the name of the parent.
*/
Child *child = new Child(_child_policy.name(),
this,
new_pid,
_sig_rec,
_root_dir,
_args,
_env.env(),
_cap_session,
_parent_services,
_resources.ep,
true,
env()->heap(),
_destruct_queue);
Family_member::insert(child);
_assign_io_channels_to(child);
/* copy our address space into the new child */
_resources.rm.replay(child->ram(), child->rm(),
child->ds_registry(), _resources.ep);
/* start executing the main thread of the new process */
child->start_forked_main_thread(ip, sp, parent_cap_addr);
/* activate child entrypoint, thereby starting the new process */
child->start();
_sysio->fork_out.pid = new_pid;
return true;
}
case SYSCALL_GETPID:
{
_sysio->getpid_out.pid = pid();
return true;
}
case SYSCALL_WAIT4:
{
Family_member *exited = _sysio->wait4_in.nohang ? poll4() : wait4();
if (exited) {
_sysio->wait4_out.pid = exited->pid();
_sysio->wait4_out.status = exited->exit_status();
Family_member::remove(exited);
PINF("submit exit signal for PID %d", exited->pid());
static_cast<Child *>(exited)->submit_exit_signal();
} else {
_sysio->wait4_out.pid = 0;
_sysio->wait4_out.status = 0;
}
return true;
}
case SYSCALL_PIPE:
{
Shared_pointer<Pipe> pipe(new Pipe, Genode::env()->heap());
Shared_pointer<Io_channel> pipe_sink(new Pipe_sink_io_channel(pipe, *_sig_rec),
Genode::env()->heap());
Shared_pointer<Io_channel> pipe_source(new Pipe_source_io_channel(pipe, *_sig_rec),
Genode::env()->heap());
_sysio->pipe_out.fd[0] = add_io_channel(pipe_source);
_sysio->pipe_out.fd[1] = add_io_channel(pipe_sink);
return true;
}
case SYSCALL_DUP2:
{
int fd = add_io_channel(io_channel_by_fd(_sysio->dup2_in.fd),
_sysio->dup2_in.to_fd);
_sysio->dup2_out.fd = fd;
return true;
}
case SYSCALL_UNLINK:
return _root_dir->unlink(_sysio, _sysio->unlink_in.path);
case SYSCALL_READLINK:
return _root_dir->readlink(_sysio, _sysio->readlink_in.path);
case SYSCALL_RENAME:
return _root_dir->rename(_sysio, _sysio->rename_in.from_path,
_sysio->rename_in.to_path);
case SYSCALL_MKDIR:
return _root_dir->mkdir(_sysio, _sysio->mkdir_in.path);
case SYSCALL_SYMLINK:
return _root_dir->symlink(_sysio, _sysio->symlink_in.newpath);
case SYSCALL_USERINFO:
{
if (_sysio->userinfo_in.request == Sysio::USERINFO_GET_UID
|| _sysio->userinfo_in.request == Sysio::USERINFO_GET_GID) {
_sysio->userinfo_out.uid = Noux::user_info()->uid;
_sysio->userinfo_out.gid = Noux::user_info()->gid;
return true;
}
/*
* Since NOUX supports exactly one user, return false if we
* got a unknown uid.
*/
if (_sysio->userinfo_in.uid != Noux::user_info()->uid)
return false;
Genode::memcpy(_sysio->userinfo_out.name, Noux::user_info()->name, sizeof(Noux::user_info()->name));
Genode::memcpy(_sysio->userinfo_out.shell, Noux::user_info()->shell, sizeof(Noux::user_info()->shell));
Genode::memcpy(_sysio->userinfo_out.home, Noux::user_info()->home, sizeof(Noux::user_info()->home));
_sysio->userinfo_out.uid = user_info()->uid;
_sysio->userinfo_out.gid = user_info()->gid;
return true;
}
case SYSCALL_GETTIMEOFDAY:
{
/**
* Since the timeout_scheduler thread is started after noux it
* basicly returns the eleapsed time since noux was started. We
* abuse this timer to provide a more useful implemenation of
* gettimeofday() to make certain programs (e.g. ping(1)) happy.
* Note: this is just a short-term solution because Genode currently
* lacks a proper time interface (there is a RTC driver however, but
* there is no interface for it).
*/
unsigned long time = Noux::timeout_scheduler()->curr_time();
_sysio->gettimeofday_out.sec = (time / 1000);
_sysio->gettimeofday_out.usec = (time % 1000) * 1000;
return true;
}
case SYSCALL_CLOCK_GETTIME:
{
/**
* It's the same procedure as in SYSCALL_GETTIMEOFDAY.
*/
unsigned long time = Noux::timeout_scheduler()->curr_time();
switch (_sysio->clock_gettime_in.clock_id) {
/* CLOCK_SECOND is used by time(3) in the libc. */
case Sysio::CLOCK_ID_SECOND:
{
_sysio->clock_gettime_out.sec = (time / 1000);
_sysio->clock_gettime_out.nsec = 0;
return true;
}
default:
{
_sysio->clock_gettime_out.sec = 0;
_sysio->clock_gettime_out.nsec = 0;
_sysio->error.clock = Sysio::CLOCK_ERR_INVALID;
return false;
}
}
return false;
}
case SYSCALL_UTIMES:
{
/**
* This systemcall is currently not implemented because we lack
* the needed mechanisms in most file-systems.
*
* But we return true anyway to keep certain programs, e.g. make
* happy.
*/
return true;
}
case SYSCALL_SOCKET:
case SYSCALL_GETSOCKOPT:
case SYSCALL_SETSOCKOPT:
case SYSCALL_ACCEPT:
case SYSCALL_BIND:
case SYSCALL_LISTEN:
case SYSCALL_SEND:
case SYSCALL_SENDTO:
case SYSCALL_RECV:
case SYSCALL_RECVFROM:
case SYSCALL_GETPEERNAME:
case SYSCALL_SHUTDOWN:
case SYSCALL_CONNECT:
return _syscall_net(sc);
case SYSCALL_INVALID: break;
}
}
catch (Invalid_fd) {
_sysio->error.general = Sysio::ERR_FD_INVALID;
PERR("Invalid file descriptor"); }
catch (...) { PERR("Unexpected exception"); }
return false;
}
/**
* Return name of init process as specified in the config
*/
static char *name_of_init_process()
{
enum { INIT_NAME_LEN = 128 };
static char buf[INIT_NAME_LEN];
Genode::config()->xml_node().sub_node("start").attribute("name").value(buf, sizeof(buf));
return buf;
}
/**
* Read command-line arguments of init process from config
*/
static Noux::Args const &args_of_init_process()
{
static char args_buf[4096];
static Noux::Args args(args_buf, sizeof(args_buf));
Genode::Xml_node start_node = Genode::config()->xml_node().sub_node("start");
try {
/* the first argument is the program name */
args.append(name_of_init_process());
Genode::Xml_node arg_node = start_node.sub_node("arg");
for (; ; arg_node = arg_node.next("arg")) {
static char buf[512];
arg_node.attribute("value").value(buf, sizeof(buf));
args.append(buf);
}
}
catch (Genode::Xml_node::Nonexistent_sub_node) { }
catch (Noux::Args::Overrun) { PERR("Argument buffer overrun"); }
return args;
}
/**
* Return string containing the environment variables of init
*
* The variable definitions are separated by zeros. The end of the string is
* marked with another zero.
*/
static Noux::Sysio::Env &env_string_of_init_process()
{
static Noux::Sysio::Env env;
int index = 0;
/* read environment variables for init process from config */
Genode::Xml_node start_node = Genode::config()->xml_node().sub_node("start");
try {
Genode::Xml_node arg_node = start_node.sub_node("env");
for (; ; arg_node = arg_node.next("env")) {
static char name_buf[256], value_buf[256];
arg_node.attribute("name").value(name_buf, sizeof(name_buf));
arg_node.attribute("value").value(value_buf, sizeof(value_buf));
Genode::size_t env_var_size = Genode::strlen(name_buf) +
Genode::strlen("=") +
Genode::strlen(value_buf) + 1;
if (index + env_var_size < sizeof(env)) {
Genode::snprintf(&env[index], env_var_size, "%s=%s", name_buf, value_buf);
index += env_var_size;
} else {
env[index] = 0;
break;
}
}
}
catch (Genode::Xml_node::Nonexistent_sub_node) { }
return env;
}
Noux::Pid_allocator *Noux::pid_allocator()
{
static Noux::Pid_allocator inst;
return &inst;
}
Noux::Timeout_scheduler *Noux::timeout_scheduler()
{
static Noux::Timeout_scheduler inst(0);
return &inst;
}
Noux::User_info* Noux::user_info()
{
static Noux::User_info inst;
return &inst;
}
Noux::Io_receptor_registry * Noux::io_receptor_registry()
{
static Noux::Io_receptor_registry _inst;
return &_inst;
}
Terminal::Connection *Noux::terminal()
{
static Terminal::Connection _inst;
return &_inst;
}
Genode::Dataspace_capability Noux::ldso_ds_cap()
{
try {
static Genode::Rom_connection rom("ld.lib.so");
static Genode::Dataspace_capability ldso_ds = rom.dataspace();
return ldso_ds;
} catch (...) { }
return Genode::Dataspace_capability();
}
void *operator new (Genode::size_t size) {
return Genode::env()->heap()->alloc(size); }
int main(int argc, char **argv)
{
using namespace Noux;
PINF("--- noux started ---");
/* register dynamic linker */
Genode::Process::dynamic_linker(ldso_ds_cap());
/* whitelist of service requests to be routed to the parent */
static Genode::Service_registry parent_services;
char const *service_names[] = { "LOG", "ROM", "Timer", 0 };
for (unsigned i = 0; service_names[i]; i++)
parent_services.insert(new Genode::Parent_service(service_names[i]));
static Genode::Cap_connection cap;
/* obtain global configuration */
try {
trace_syscalls = config()->xml_node().attribute("trace_syscalls").has_value("yes");
} catch (Xml_node::Nonexistent_attribute) { }
/* initialize virtual file system */
static Dir_file_system
root_dir(config()->xml_node().sub_node("fstab"));
/* set user information */
try {
user_info()->set_info(config()->xml_node().sub_node("user"));
}
catch (...) { }
/* initialize network */
init_network();
/*
* Entrypoint used to virtualize child resources such as RAM, RM
*/
enum { STACK_SIZE = 1024*sizeof(long) };
static Genode::Rpc_entrypoint resources_ep(&cap, STACK_SIZE, "noux_rsc_ep");
/* create init process */
static Genode::Signal_receiver sig_rec;
static Destruct_queue destruct_queue;
init_child = new Noux::Child(name_of_init_process(),
0,
pid_allocator()->alloc(),
&sig_rec,
&root_dir,
args_of_init_process(),
env_string_of_init_process(),
&cap,
parent_services,
resources_ep,
false,
env()->heap(),
destruct_queue);
/*
* I/O channels must be dynamically allocated to handle cases where the
* init program closes one of these.
*/
typedef Terminal_io_channel Tio; /* just a local abbreviation */
Shared_pointer<Io_channel>
channel_0(new Tio(*Noux::terminal(), Tio::STDIN, sig_rec), Genode::env()->heap()),
channel_1(new Tio(*Noux::terminal(), Tio::STDOUT, sig_rec), Genode::env()->heap()),
channel_2(new Tio(*Noux::terminal(), Tio::STDERR, sig_rec), Genode::env()->heap());
init_child->add_io_channel(channel_0, 0);
init_child->add_io_channel(channel_1, 1);
init_child->add_io_channel(channel_2, 2);
init_child->start();
/* handle asynchronous events */
while (init_child) {
/*
* limit the scope of the 'Signal' object, so the signal context may
* get freed by the destruct queue
*/
{
Genode::Signal signal = sig_rec.wait_for_signal();
Signal_dispatcher_base *dispatcher =
static_cast<Signal_dispatcher_base *>(signal.context());
for (unsigned i = 0; i < signal.num(); i++)
dispatcher->dispatch(1);
}
destruct_queue.flush();
if (verbose_quota)
PINF("quota: avail=%zd, used=%zd",
env()->ram_session()->avail(),
env()->ram_session()->used());
}
PINF("-- exiting noux ---");
return 0;
}
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