metasploit-framework/external/source/vncdll/winvnc/omnithread/nt.cpp

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// Package : omnithread
// omnithread/nt.cc Created : 6/95 tjr
//
// Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved.
//
// This file is part of the omnithread library
//
// The omnithread library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free
// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA
//
//
// Implementation of OMNI thread abstraction for NT threads
//
#include <stdlib.h>
#include <errno.h>
#include "omnithread.h"
#include <process.h>
#define DB(x) // x
//#include <iostream.h> or #include <iostream> if DB is on.
static void get_time_now(unsigned long* abs_sec, unsigned long* abs_nsec);
///////////////////////////////////////////////////////////////////////////
//
// Mutex
//
///////////////////////////////////////////////////////////////////////////
omni_mutex::omni_mutex(void)
{
InitializeCriticalSection(&crit);
}
omni_mutex::~omni_mutex(void)
{
DeleteCriticalSection(&crit);
}
void
omni_mutex::lock(void)
{
EnterCriticalSection(&crit);
}
void
omni_mutex::unlock(void)
{
LeaveCriticalSection(&crit);
}
///////////////////////////////////////////////////////////////////////////
//
// Condition variable
//
///////////////////////////////////////////////////////////////////////////
//
// Condition variables are tricky to implement using NT synchronisation
// primitives, since none of them have the atomic "release mutex and wait to be
// signalled" which is central to the idea of a condition variable. To get
// around this the solution is to record which threads are waiting and
// explicitly wake up those threads.
//
// Here we implement a condition variable using a list of waiting threads
// (protected by a critical section), and a per-thread semaphore (which
// actually only needs to be a binary semaphore).
//
// To wait on the cv, a thread puts itself on the list of waiting threads for
// that cv, then releases the mutex and waits on its own personal semaphore. A
// signalling thread simply takes a thread from the head of the list and kicks
// that thread's semaphore. Broadcast is simply implemented by kicking the
// semaphore of each waiting thread.
//
// The only other tricky part comes when a thread gets a timeout from a timed
// wait on its semaphore. Between returning with a timeout from the wait and
// entering the critical section, a signalling thread could get in, kick the
// waiting thread's semaphore and remove it from the list. If this happens,
// the waiting thread's semaphore is now out of step so it needs resetting, and
// the thread should indicate that it was signalled rather than that it timed
// out.
//
// It is possible that the thread calling wait or timedwait is not a
// omni_thread. In this case we have to provide a temporary data structure,
// i.e. for the duration of the call, for the thread to link itself on the
// list of waiting threads. _internal_omni_thread_dummy provides such
// a data structure and _internal_omni_thread_helper is a helper class to
// deal with this special case for wait() and timedwait(). Once created,
// the _internal_omni_thread_dummy is cached for use by the next wait() or
// timedwait() call from a non-omni_thread. This is probably worth doing
// because creating a Semaphore is quite heavy weight.
class _internal_omni_thread_helper;
class _internal_omni_thread_dummy : public omni_thread {
public:
inline _internal_omni_thread_dummy() : next(0) { }
inline ~_internal_omni_thread_dummy() { }
friend class _internal_omni_thread_helper;
private:
_internal_omni_thread_dummy* next;
};
class _internal_omni_thread_helper {
public:
inline _internal_omni_thread_helper() {
d = 0;
t = omni_thread::self();
if (!t) {
omni_mutex_lock sync(cachelock);
if (cache) {
d = cache;
cache = cache->next;
}
else {
d = new _internal_omni_thread_dummy;
}
t = d;
}
}
inline ~_internal_omni_thread_helper() {
if (d) {
omni_mutex_lock sync(cachelock);
d->next = cache;
cache = d;
}
}
inline operator omni_thread* () { return t; }
inline omni_thread* operator->() { return t; }
static _internal_omni_thread_dummy* cache;
static omni_mutex cachelock;
private:
_internal_omni_thread_dummy* d;
omni_thread* t;
};
_internal_omni_thread_dummy* _internal_omni_thread_helper::cache = 0;
omni_mutex _internal_omni_thread_helper::cachelock;
omni_condition::omni_condition(omni_mutex* m) : mutex(m)
{
InitializeCriticalSection(&crit);
waiting_head = waiting_tail = NULL;
}
omni_condition::~omni_condition(void)
{
DeleteCriticalSection(&crit);
DB( if (waiting_head != NULL) {
cerr << "omni_condition::~omni_condition: list of waiting threads "
<< "is not empty\n";
} )
}
void
omni_condition::wait(void)
{
_internal_omni_thread_helper me;
EnterCriticalSection(&crit);
me->cond_next = NULL;
me->cond_prev = waiting_tail;
if (waiting_head == NULL)
waiting_head = me;
else
waiting_tail->cond_next = me;
waiting_tail = me;
me->cond_waiting = TRUE;
LeaveCriticalSection(&crit);
mutex->unlock();
DWORD result = WaitForSingleObject(me->cond_semaphore, INFINITE);
mutex->lock();
if (result != WAIT_OBJECT_0)
throw omni_thread_fatal(GetLastError());
}
int
omni_condition::timedwait(unsigned long abs_sec, unsigned long abs_nsec)
{
_internal_omni_thread_helper me;
EnterCriticalSection(&crit);
me->cond_next = NULL;
me->cond_prev = waiting_tail;
if (waiting_head == NULL)
waiting_head = me;
else
waiting_tail->cond_next = me;
waiting_tail = me;
me->cond_waiting = TRUE;
LeaveCriticalSection(&crit);
mutex->unlock();
unsigned long now_sec, now_nsec;
get_time_now(&now_sec, &now_nsec);
DWORD timeout = (abs_sec-now_sec) * 1000 + (abs_nsec-now_nsec) / 1000000;
if ((abs_sec <= now_sec) && ((abs_sec < now_sec) || (abs_nsec < abs_nsec)))
timeout = 0;
DWORD result = WaitForSingleObject(me->cond_semaphore, timeout);
if (result == WAIT_TIMEOUT) {
EnterCriticalSection(&crit);
if (me->cond_waiting) {
if (me->cond_prev != NULL)
me->cond_prev->cond_next = me->cond_next;
else
waiting_head = me->cond_next;
if (me->cond_next != NULL)
me->cond_next->cond_prev = me->cond_prev;
else
waiting_tail = me->cond_prev;
me->cond_waiting = FALSE;
LeaveCriticalSection(&crit);
mutex->lock();
return 0;
}
//
// We timed out but another thread still signalled us. Wait for
// the semaphore (it _must_ have been signalled) to decrement it
// again. Return that we were signalled, not that we timed out.
//
LeaveCriticalSection(&crit);
result = WaitForSingleObject(me->cond_semaphore, INFINITE);
}
if (result != WAIT_OBJECT_0)
throw omni_thread_fatal(GetLastError());
mutex->lock();
return 1;
}
void
omni_condition::signal(void)
{
EnterCriticalSection(&crit);
if (waiting_head != NULL) {
omni_thread* t = waiting_head;
waiting_head = t->cond_next;
if (waiting_head == NULL)
waiting_tail = NULL;
else
waiting_head->cond_prev = NULL;
t->cond_waiting = FALSE;
if (!ReleaseSemaphore(t->cond_semaphore, 1, NULL)) {
int rc = GetLastError();
LeaveCriticalSection(&crit);
throw omni_thread_fatal(rc);
}
}
LeaveCriticalSection(&crit);
}
void
omni_condition::broadcast(void)
{
EnterCriticalSection(&crit);
while (waiting_head != NULL) {
omni_thread* t = waiting_head;
waiting_head = t->cond_next;
if (waiting_head == NULL)
waiting_tail = NULL;
else
waiting_head->cond_prev = NULL;
t->cond_waiting = FALSE;
if (!ReleaseSemaphore(t->cond_semaphore, 1, NULL)) {
int rc = GetLastError();
LeaveCriticalSection(&crit);
throw omni_thread_fatal(rc);
}
}
LeaveCriticalSection(&crit);
}
///////////////////////////////////////////////////////////////////////////
//
// Counting semaphore
//
///////////////////////////////////////////////////////////////////////////
#define SEMAPHORE_MAX 0x7fffffff
omni_semaphore::omni_semaphore(unsigned int initial)
{
nt_sem = CreateSemaphore(NULL, initial, SEMAPHORE_MAX, NULL);
if (nt_sem == NULL) {
DB( cerr << "omni_semaphore::omni_semaphore: CreateSemaphore error "
<< GetLastError() << endl );
throw omni_thread_fatal(GetLastError());
}
}
omni_semaphore::~omni_semaphore(void)
{
if (!CloseHandle(nt_sem)) {
DB( cerr << "omni_semaphore::~omni_semaphore: CloseHandle error "
<< GetLastError() << endl );
throw omni_thread_fatal(GetLastError());
}
}
void
omni_semaphore::wait(void)
{
if (WaitForSingleObject(nt_sem, INFINITE) != WAIT_OBJECT_0)
throw omni_thread_fatal(GetLastError());
}
int
omni_semaphore::trywait(void)
{
switch (WaitForSingleObject(nt_sem, 0)) {
case WAIT_OBJECT_0:
return 1;
case WAIT_TIMEOUT:
return 0;
}
throw omni_thread_fatal(GetLastError());
return 0; /* keep msvc++ happy */
}
void
omni_semaphore::post(void)
{
if (!ReleaseSemaphore(nt_sem, 1, NULL))
throw omni_thread_fatal(GetLastError());
}
///////////////////////////////////////////////////////////////////////////
//
// Thread
//
///////////////////////////////////////////////////////////////////////////
//
// Static variables
//
int omni_thread::init_t::count = 0;
omni_mutex* omni_thread::next_id_mutex;
int omni_thread::next_id = 0;
static DWORD self_tls_index;
//
// Initialisation function (gets called before any user code).
//
omni_thread::init_t::init_t(void)
{
if (count++ != 0) // only do it once however many objects get created.
return;
DB(cerr << "omni_thread::init: NT implementation initialising\n");
self_tls_index = TlsAlloc();
if (self_tls_index == 0xffffffff)
throw omni_thread_fatal(GetLastError());
next_id_mutex = new omni_mutex;
//
// Create object for this (i.e. initial) thread.
//
omni_thread* t = new omni_thread;
t->_state = STATE_RUNNING;
if (!DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
GetCurrentProcess(), &t->handle,
0, FALSE, DUPLICATE_SAME_ACCESS))
throw omni_thread_fatal(GetLastError());
t->nt_id = GetCurrentThreadId();
DB(cerr << "initial thread " << t->id() << " NT thread id " << t->nt_id
<< endl);
if (!TlsSetValue(self_tls_index, (LPVOID)t))
throw omni_thread_fatal(GetLastError());
if (!SetThreadPriority(t->handle, nt_priority(PRIORITY_NORMAL)))
throw omni_thread_fatal(GetLastError());
}
//
// Wrapper for thread creation.
//
extern "C"
unsigned __stdcall
omni_thread_wrapper(void* ptr)
{
omni_thread* me = (omni_thread*)ptr;
DB(cerr << "omni_thread_wrapper: thread " << me->id()
<< " started\n");
TlsSetValue(self_tls_index, (LPVOID)me);
//if (!TlsSetValue(self_tls_index, (LPVOID)me))
// throw omni_thread_fatal(GetLastError());
//
// Now invoke the thread function with the given argument.
//
if (me->fn_void != NULL) {
(*me->fn_void)(me->thread_arg);
omni_thread::exit();
}
if (me->fn_ret != NULL) {
void* return_value = (*me->fn_ret)(me->thread_arg);
omni_thread::exit(return_value);
}
if (me->detached) {
me->run(me->thread_arg);
omni_thread::exit();
} else {
void* return_value = me->run_undetached(me->thread_arg);
omni_thread::exit(return_value);
}
// should never get here.
return 0;
}
//
// Constructors for omni_thread - set up the thread object but don't
// start it running.
//
// construct a detached thread running a given function.
omni_thread::omni_thread(void (*fn)(void*), void* arg, priority_t pri)
{
common_constructor(arg, pri, 1);
fn_void = fn;
fn_ret = NULL;
}
// construct an undetached thread running a given function.
omni_thread::omni_thread(void* (*fn)(void*), void* arg, priority_t pri)
{
common_constructor(arg, pri, 0);
fn_void = NULL;
fn_ret = fn;
}
// construct a thread which will run either run() or run_undetached().
omni_thread::omni_thread(void* arg, priority_t pri)
{
common_constructor(arg, pri, 1);
fn_void = NULL;
fn_ret = NULL;
}
// common part of all constructors.
void
omni_thread::common_constructor(void* arg, priority_t pri, int det)
{
_state = STATE_NEW;
_priority = pri;
next_id_mutex->lock();
_id = next_id++;
next_id_mutex->unlock();
thread_arg = arg;
detached = det; // may be altered in start_undetached()
cond_semaphore = CreateSemaphore(NULL, 0, SEMAPHORE_MAX, NULL);
if (cond_semaphore == NULL)
throw omni_thread_fatal(GetLastError());
cond_next = cond_prev = NULL;
cond_waiting = FALSE;
handle = NULL;
}
//
// Destructor for omni_thread.
//
omni_thread::~omni_thread(void)
{
DB(cerr << "destructor called for thread " << id() << endl);
if ((handle != NULL) && !CloseHandle(handle))
throw omni_thread_fatal(GetLastError());
if (!CloseHandle(cond_semaphore))
throw omni_thread_fatal(GetLastError());
}
//
// Start the thread
//
void
omni_thread::start(void)
{
omni_mutex_lock l(mutex);
if (_state != STATE_NEW)
throw omni_thread_invalid();
unsigned int t;
handle = (HANDLE)_beginthreadex(
NULL,
0,
omni_thread_wrapper,
(LPVOID)this,
CREATE_SUSPENDED,
&t);
nt_id = t;
if (handle == NULL)
throw omni_thread_fatal(GetLastError());
if (!SetThreadPriority(handle, _priority))
throw omni_thread_fatal(GetLastError());
if (ResumeThread(handle) == 0xffffffff)
throw omni_thread_fatal(GetLastError());
_state = STATE_RUNNING;
}
//
// Start a thread which will run the member function run_undetached().
//
void
omni_thread::start_undetached(void)
{
if ((fn_void != NULL) || (fn_ret != NULL))
throw omni_thread_invalid();
detached = 0;
start();
}
//
// join - simply check error conditions & call WaitForSingleObject.
//
void
omni_thread::join(void** status)
{
mutex.lock();
if ((_state != STATE_RUNNING) && (_state != STATE_TERMINATED)) {
mutex.unlock();
throw omni_thread_invalid();
}
mutex.unlock();
if (this == self())
throw omni_thread_invalid();
if (detached)
throw omni_thread_invalid();
DB(cerr << "omni_thread::join: doing WaitForSingleObject\n");
if (WaitForSingleObject(handle, INFINITE) != WAIT_OBJECT_0)
throw omni_thread_fatal(GetLastError());
DB(cerr << "omni_thread::join: WaitForSingleObject succeeded\n");
if (status)
*status = return_val;
delete this;
}
//
// Change this thread's priority.
//
void
omni_thread::set_priority(priority_t pri)
{
omni_mutex_lock l(mutex);
if (_state != STATE_RUNNING)
throw omni_thread_invalid();
_priority = pri;
if (!SetThreadPriority(handle, nt_priority(pri)))
throw omni_thread_fatal(GetLastError());
}
//
// create - construct a new thread object and start it running. Returns thread
// object if successful, null pointer if not.
//
// detached version
omni_thread*
omni_thread::create(void (*fn)(void*), void* arg, priority_t pri)
{
omni_thread* t = new omni_thread(fn, arg, pri);
t->start();
return t;
}
// undetached version
omni_thread*
omni_thread::create(void* (*fn)(void*), void* arg, priority_t pri)
{
omni_thread* t = new omni_thread(fn, arg, pri);
t->start();
return t;
}
//
// exit() _must_ lock the mutex even in the case of a detached thread. This is
// because a thread may run to completion before the thread that created it has
// had a chance to get out of start(). By locking the mutex we ensure that the
// creating thread must have reached the end of start() before we delete the
// thread object. Of course, once the call to start() returns, the user can
// still incorrectly refer to the thread object, but that's their problem.
//
void
omni_thread::exit(void* return_value)
{
omni_thread* me = self();
if (me)
{
me->mutex.lock();
me->_state = STATE_TERMINATED;
me->mutex.unlock();
DB(cerr << "omni_thread::exit: thread " << me->id() << " detached "
<< me->detached << " return value " << return_value << endl);
if (me->detached) {
delete me;
} else {
me->return_val = return_value;
}
}
else
{
DB(cerr << "omni_thread::exit: called with a non-omnithread. Exit quietly." << endl);
}
// _endthreadex() does not automatically closes the thread handle.
// The omni_thread dtor closes the thread handle.
_endthreadex(0);
}
omni_thread*
omni_thread::self(void)
{
LPVOID me;
me = TlsGetValue(self_tls_index);
if (me == NULL) {
DB(cerr << "omni_thread::self: called with a non-ominthread. NULL is returned." << endl);
}
return (omni_thread*)me;
}
void
omni_thread::yield(void)
{
Sleep(0);
}
#define MAX_SLEEP_SECONDS (DWORD)4294966 // (2**32-2)/1000
void
omni_thread::sleep(unsigned long secs, unsigned long nanosecs)
{
if (secs <= MAX_SLEEP_SECONDS) {
Sleep(secs * 1000 + nanosecs / 1000000);
return;
}
DWORD no_of_max_sleeps = secs / MAX_SLEEP_SECONDS;
for (DWORD i = 0; i < no_of_max_sleeps; i++)
Sleep(MAX_SLEEP_SECONDS * 1000);
Sleep((secs % MAX_SLEEP_SECONDS) * 1000 + nanosecs / 1000000);
}
void
omni_thread::get_time(unsigned long* abs_sec, unsigned long* abs_nsec,
unsigned long rel_sec, unsigned long rel_nsec)
{
get_time_now(abs_sec, abs_nsec);
*abs_nsec += rel_nsec;
*abs_sec += rel_sec + *abs_nsec / 1000000000;
*abs_nsec = *abs_nsec % 1000000000;
}
int
omni_thread::nt_priority(priority_t pri)
{
switch (pri) {
case PRIORITY_LOW:
return THREAD_PRIORITY_LOWEST;
case PRIORITY_NORMAL:
return THREAD_PRIORITY_NORMAL;
case PRIORITY_HIGH:
return THREAD_PRIORITY_HIGHEST;
}
throw omni_thread_invalid();
return 0; /* keep msvc++ happy */
}
static void
get_time_now(unsigned long* abs_sec, unsigned long* abs_nsec)
{
static int days_in_preceding_months[12]
= { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
static int days_in_preceding_months_leap[12]
= { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 };
SYSTEMTIME st;
GetSystemTime(&st);
*abs_nsec = st.wMilliseconds * 1000000;
// this formula should work until 1st March 2100
DWORD days = ((st.wYear - 1970) * 365 + (st.wYear - 1969) / 4
+ ((st.wYear % 4)
? days_in_preceding_months[st.wMonth - 1]
: days_in_preceding_months_leap[st.wMonth - 1])
+ st.wDay - 1);
*abs_sec = st.wSecond + 60 * (st.wMinute + 60 * (st.wHour + 24 * days));
}