thread.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

/* thread.cc: Locking and threading module functions

   Copyright 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

   Originally written by Marco Fuykschot <[e-mail]>
   Substantialy enhanced by Robert Collins <[e-mail]>

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

/* Implementation overview and caveats:

   Win32 puts some contraints on what can and cannot be implemented.  Where
   possible we work around those contrainsts.  Where we cannot work around
   the constraints we either pretend to be conformant, or return an error
   code.

   Some caveats: PROCESS_SHARED objects while they pretend to be process
   shared, may not actually work.  Some test cases are needed to determine
   win32's behaviour.  My suspicion is that the win32 handle needs to be
   opened with different flags for proper operation.

   R.Collins, April 2001.  */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#ifdef _MT_SAFE
#include "winsup.h"
#include <limits.h>
#include <errno.h>
#include "cygerrno.h"
#include <assert.h>
#include <stdlib.h>
#include <syslog.h>
#include "pinfo.h"
#include "perprocess.h"
#include "security.h"
#include <semaphore.h>
#include <stdio.h>
#include <sys/timeb.h>

extern int threadsafe;

struct _reent *
_reent_clib ()
{
  struct __reent_t *_r =
    (struct __reent_t *) MT_INTERFACE->reent_key.get ();

#ifdef _CYG_THREAD_FAILSAFE
  if (_r == 0)
    system_printf ("local thread storage not inited");
#endif
  return _r->_clib;
}

struct _winsup_t *
_reent_winsup ()
{
  struct __reent_t *_r =
    (struct __reent_t *) MT_INTERFACE->reent_key.get ();

#ifdef _CYG_THREAD_FAILSAFE
  if (_r == 0)
    system_printf ("local thread storage not inited");
#endif
  return _r->_winsup;
}

inline LPCRITICAL_SECTION
ResourceLocks::Lock (int _resid)
{
#ifdef _CYG_THREAD_FAILSAFE
  if (!inited)
    system_printf ("lock called before initialization");

  thread_printf
    ("Get Resource lock %d ==> %p for %p , real : %d , threadid %d ", _resid,
     &lock, user_data, myself->pid, GetCurrentThreadId ());
#endif
  return &lock;
}

void
SetResourceLock (int _res_id, int _mode, const char *_function)
{
#ifdef _CYG_THREAD_FAILSAFE
  thread_printf ("Set resource lock %d mode %d for %s start",
		 _res_id, _mode, _function);
#endif
  EnterCriticalSection (user_data->resourcelocks->Lock (_res_id));

#ifdef _CYG_THREAD_FAILSAFE
  user_data->resourcelocks->owner = GetCurrentThreadId ();
  user_data->resourcelocks->count++;
#endif
}

void
ReleaseResourceLock (int _res_id, int _mode, const char *_function)
{
#ifdef _CYG_THREAD_FAILSAFE
  thread_printf ("Release resource lock %d mode %d for %s done", _res_id,
		 _mode, _function);

  AssertResourceOwner (_res_id, _mode);
  user_data->resourcelocks->count--;
  if (user_data->resourcelocks->count == 0)
    user_data->resourcelocks->owner = 0;
#endif

  LeaveCriticalSection (user_data->resourcelocks->Lock (_res_id));
}

#ifdef _CYG_THREAD_FAILSAFE
void
AssertResourceOwner (int _res_id, int _mode)
{

  thread_printf
    ("Assert Resource lock %d ==> for %p , real : %d , threadid %d count %d owner %d",
     _res_id, user_data, myself->pid, GetCurrentThreadId (),
     user_data->resourcelocks->count, user_data->resourcelocks->owner);
  if (user_data && (user_data->resourcelocks->owner != GetCurrentThreadId ()))
    system_printf ("assertion failed, not the resource owner");
}

#endif

void
ResourceLocks::Init ()
{
  InitializeCriticalSection (&lock);
  inited = true;

#ifdef _CYG_THREAD_FAILSAFE
  owner = 0;
  count = 0;
#endif

  thread_printf ("lock %p inited by %p , %d", &lock, user_data, myself->pid);
}

void
ResourceLocks::Delete ()
{
  if (inited)
    {
      thread_printf ("Close Resource Locks %p ", &lock);
      DeleteCriticalSection (&lock);
      inited = false;
    }
}

void
MTinterface::Init (int forked)
{
  reents._clib = _impure_ptr;
  reents._winsup = &winsup_reent;
  winsup_reent._process_logmask = LOG_UPTO (LOG_DEBUG);

  if (!forked)
    reent_key.set (&reents);

  pthread_mutex::initMutex ();
}

void
MTinterface::fixup_before_fork (void)
{
  pthread_key::fixup_before_fork ();
}

/* This function is called from a single threaded process */
void
MTinterface::fixup_after_fork (void)
{
  pthread_key::fixup_after_fork ();
  pthread_mutex *mutex = mutexs;
  debug_printf ("mutexs is %x",mutexs);
  while (mutex)
    {
      mutex->fixup_after_fork ();
      mutex = mutex->next;
    }
  pthread_cond *cond = conds;
  debug_printf ("conds is %x",conds);
  while (cond)
    {
      cond->fixup_after_fork ();
      cond = cond->next;
    }
  semaphore *sem = semaphores;
  debug_printf ("semaphores is %x",semaphores);
  while (sem)
    {
      sem->fixup_after_fork ();
      sem = sem->next;
    }

  pthread::initMainThread (true);

  threadcount = 1;
}

/* pthread calls */

/* static methods */
void
pthread::initMainThread (bool do_init)
{
  if (!do_init)
    return;

  pthread *thread = getTlsSelfPointer ();
  if (!thread)
    {
      thread = new pthread ();
      if (!thread)
        api_fatal ("failed to create mainthread object");
    }

  thread->initCurrentThread ();
}

pthread *
pthread::self ()
{
  pthread *thread = getTlsSelfPointer ();
  if (thread)
    return thread;
  return pthreadNull::getNullpthread ();
}

void
pthread::setTlsSelfPointer (pthread *thisThread)
{
  MT_INTERFACE->thread_self_key.set (thisThread);
}

pthread *
pthread::getTlsSelfPointer ()
{
  return (pthread *) MT_INTERFACE->thread_self_key.get ();
}



/* member methods */
pthread::pthread ():verifyable_object (PTHREAD_MAGIC), win32_obj_id (0),
		    cancelstate (0), canceltype (0), cancel_event (0),
		    joiner (NULL), cleanup_stack (NULL)
{
}

pthread::~pthread ()
{
  if (win32_obj_id)
    CloseHandle (win32_obj_id);
  if (cancel_event)
    CloseHandle (cancel_event);
}

void
pthread::setThreadIdtoCurrent ()
{
  thread_id = GetCurrentThreadId ();
}

void
pthread::precreate (pthread_attr *newattr)
{
  pthread_mutex *verifyable_mutex_obj = &mutex;

  /* already running ? */
  if (win32_obj_id)
    return;

  if (newattr)
    {
      attr.joinable = newattr->joinable;
      attr.contentionscope = newattr->contentionscope;
      attr.inheritsched = newattr->inheritsched;
      attr.stacksize = newattr->stacksize;
    }

  if (!pthread_mutex::isGoodObject (&verifyable_mutex_obj))
    {
      thread_printf ("New thread object access mutex is not valid. this %p",
		     this);
      magic = 0;
      return;
    }

  cancel_event = ::CreateEvent (&sec_none_nih, TRUE, FALSE, NULL);
  if (!cancel_event)
    {
      system_printf ("couldn't create cancel event, this %p LastError %E", this);
      /* we need the event for correct behaviour */
      magic = 0;
      return;
    }
}

void
pthread::create (void *(*func) (void *), pthread_attr *newattr,
		 void *threadarg)
{
  precreate (newattr);
  if (!magic)
      return;
   function = func;
   arg = threadarg;

  win32_obj_id = ::CreateThread (&sec_none_nih, attr.stacksize,
				(LPTHREAD_START_ROUTINE) thread_init_wrapper,
				this, CREATE_SUSPENDED, &thread_id);

  if (!win32_obj_id)
    {
      thread_printf ("CreateThread failed: this %p LastError %E", this);
      magic = 0;
    }
  else {
      postcreate ();
      ResumeThread (win32_obj_id);
  }
}

void
pthread::postcreate ()
{
    InterlockedIncrement (&MT_INTERFACE->threadcount);
    /* FIXME: set the priority appropriately for system contention scope */
    if (attr.inheritsched == PTHREAD_EXPLICIT_SCHED)
      {
	/* FIXME: set the scheduling settings for the new thread */
	/* sched_thread_setparam (win32_obj_id, attr.schedparam); */
      }
}

void
pthread::exit (void *value_ptr)
{
  class pthread *thread = this;

  // run cleanup handlers
  pop_all_cleanup_handlers ();

  pthread_key::runAllDestructors ();

  mutex.Lock ();
  // cleanup if thread is in detached state and not joined
  if (__pthread_equal (&joiner, &thread))
    delete this;
  else
    {
      return_ptr = value_ptr;
      mutex.UnLock ();
    }

  if (InterlockedDecrement (&MT_INTERFACE->threadcount) == 0)
    ::exit (0);
  else
    ExitThread (0);
}

int
pthread::cancel (void)
{
  class pthread *thread = this;
  class pthread *self = pthread::self ();

  mutex.Lock ();

  if (canceltype == PTHREAD_CANCEL_DEFERRED ||
      cancelstate == PTHREAD_CANCEL_DISABLE)
    {
      // cancel deferred
      mutex.UnLock ();
      SetEvent (cancel_event);
      return 0;
    }

  else if (__pthread_equal (&thread, &self))
    {
      mutex.UnLock ();
      cancel_self ();
      return 0; // Never reached
    }

  // cancel asynchronous
  SuspendThread (win32_obj_id);
  if (WaitForSingleObject (win32_obj_id, 0) == WAIT_TIMEOUT)
    {
      CONTEXT context;
      context.ContextFlags = CONTEXT_CONTROL;
      GetThreadContext (win32_obj_id, &context);
      context.Eip = (DWORD) pthread::static_cancel_self;
      SetThreadContext (win32_obj_id, &context);
    }
  mutex.UnLock ();
  ResumeThread (win32_obj_id);

  return 0;
/*
  TODO: insert  pthread_testcancel into the required functions
  the required function list is: *indicates done, X indicates not present in cygwin.
aio_suspend ()
*close ()
*creat ()
fcntl ()
fsync ()
getmsg ()
getpmsg ()
lockf ()
mq_receive ()
mq_send ()
msgrcv ()
msgsnd ()
msync ()
nanosleep ()
open ()
pause ()
poll ()
pread ()
pthread_cond_timedwait ()
pthread_cond_wait ()
*pthread_join ()
pthread_testcancel ()
putmsg ()
putpmsg ()
pwrite ()
read ()
readv ()
select ()
sem_wait ()
sigpause ()
sigsuspend ()
sigtimedwait ()
sigwait ()
sigwaitinfo ()
*sleep ()
system ()
tcdrain ()
*usleep ()
wait ()
wait3()
waitid ()
waitpid ()
write ()
writev ()

the optional list is:
catclose ()
catgets ()
catopen ()
closedir ()
closelog ()
ctermid ()
dbm_close ()
dbm_delete ()
dbm_fetch ()
dbm_nextkey ()
dbm_open ()
dbm_store ()
dlclose ()
dlopen ()
endgrent ()
endpwent ()
endutxent ()
fclose ()
fcntl ()
fflush ()
fgetc ()
fgetpos ()
fgets ()
fgetwc ()
fgetws ()
fopen ()
fprintf ()
fputc ()
fputs ()
fputwc ()
fputws ()
fread ()
freopen ()
fscanf ()
fseek ()
fseeko ()
fsetpos ()
ftell ()
ftello ()
ftw ()
fwprintf ()
fwrite ()
fwscanf ()
getc ()
getc_unlocked ()
getchar ()
getchar_unlocked ()
getcwd ()
getdate ()
getgrent ()
getgrgid ()
getgrgid_r ()
getgrnam ()
getgrnam_r ()
getlogin ()
getlogin_r ()
getpwent ()
*getpwnam ()
*getpwnam_r ()
*getpwuid ()
*getpwuid_r ()
gets ()
getutxent ()
getutxid ()
getutxline ()
getw ()
getwc ()
getwchar ()
getwd ()
glob ()
iconv_close ()
iconv_open ()
ioctl ()
lseek ()
mkstemp ()
nftw ()
opendir ()
openlog ()
pclose ()
perror ()
popen ()
printf ()
putc ()
putc_unlocked ()
putchar ()
putchar_unlocked ()
puts ()
pututxline ()
putw ()
putwc ()
putwchar ()
readdir ()
readdir_r ()
remove ()
rename ()
rewind ()
rewinddir ()
scanf ()
seekdir ()
semop ()
setgrent ()
setpwent ()
setutxent ()
strerror ()
syslog ()
tmpfile ()
tmpnam ()
ttyname ()
ttyname_r ()
ungetc ()
ungetwc ()
unlink ()
vfprintf ()
vfwprintf ()
vprintf ()
vwprintf ()
wprintf ()
wscanf ()

Note, that for fcntl (), for any value of the cmd argument.

And we must not introduce cancellation points anywhere else that's part of the posix or
opengroup specs.
 */
}

void
pthread::testcancel (void)
{
  if (cancelstate == PTHREAD_CANCEL_DISABLE)
    return;

  if (WAIT_OBJECT_0 == WaitForSingleObject (cancel_event, 0))
    cancel_self ();
}

void
pthread::static_cancel_self (void)
{
  pthread::self ()->cancel_self ();
}


int
pthread::setcancelstate (int state, int *oldstate)
{
  int result = 0;

  mutex.Lock ();

  if (state != PTHREAD_CANCEL_ENABLE && state != PTHREAD_CANCEL_DISABLE)
    result = EINVAL;
  else
    {
      if (oldstate)
	*oldstate = cancelstate;
      cancelstate = state;
    }

  mutex.UnLock ();

  return result;
}

int
pthread::setcanceltype (int type, int *oldtype)
{
  int result = 0;

  mutex.Lock ();

  if (type != PTHREAD_CANCEL_DEFERRED && type != PTHREAD_CANCEL_ASYNCHRONOUS)
    result = EINVAL;
  else
    {
      if (oldtype)
	*oldtype = canceltype;
      canceltype = type;
    }

  mutex.UnLock ();

  return result;
}

void
pthread::push_cleanup_handler (__pthread_cleanup_handler *handler)
{
  if (this != self ())
    // TODO: do it?
    api_fatal ("Attempt to push a cleanup handler across threads");
  handler->next = cleanup_stack;
  InterlockedExchangePointer (&cleanup_stack, handler);
}

void
pthread::pop_cleanup_handler (int const execute)
{
  if (this != self ())
    // TODO: send a signal or something to the thread ?
    api_fatal ("Attempt to execute a cleanup handler across threads");

  mutex.Lock ();