newlib/winsup/cygwin/thread.h

/* thread.h: Locking and threading module definitions

   Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009,
   2010, 2011, 2012, 2013, 2014, 2015 Red Hat, Inc.

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. */

#pragma once

#define LOCK_MMAP_LIST   1

#define WRITE_LOCK 1
#define READ_LOCK  2

/* Default is a 1 Megs stack with a 4K guardpage.  The pthread stacksize
   does not include the guardpage size, so we subtract the default guardpage
   size. Additionally, the Windows stack handling disallows to use the last
   two pages as guard page  (tested on XP and W7).  That results in a zone of
   three pages which have to be subtract to get the actual stack size. */
#define PTHREAD_DEFAULT_STACKSIZE (1024 * 1024 - 3 * wincap.page_size ())
#define PTHREAD_DEFAULT_GUARDSIZE (wincap.page_size ())

#include <pthread.h>
#include <limits.h>
#include "security.h"
#include <errno.h>
#include "cygerrno.h"
#include "cygwait.h"

class fast_mutex
{
public:
  fast_mutex () :
    lock_counter (0), win32_obj_id (0)
  {
  }

  ~fast_mutex ()
  {
    if(win32_obj_id)
      CloseHandle (win32_obj_id);
  }

  bool init ()
  {
    lock_counter = 0;
    win32_obj_id = ::CreateEvent (&sec_none_nih, false, false, NULL);
    if (!win32_obj_id)
      {
	debug_printf ("CreateEvent failed. %E");
	return false;
      }
    return true;
  }

  void lock ()
  {
    if (InterlockedIncrement (&lock_counter) != 1)
      cygwait (win32_obj_id, cw_infinite, cw_sig | cw_sig_restart);
  }

  void unlock ()
  {
    if (InterlockedDecrement (&lock_counter))
      ::SetEvent (win32_obj_id);
  }

private:
  LONG lock_counter;
  HANDLE win32_obj_id;
};

class per_process;
class pinfo;

#define PTHREAD_MAGIC 0xdf0df045
#define PTHREAD_MUTEX_MAGIC PTHREAD_MAGIC+1
#define PTHREAD_KEY_MAGIC PTHREAD_MAGIC+2
#define PTHREAD_ATTR_MAGIC PTHREAD_MAGIC+3
#define PTHREAD_MUTEXATTR_MAGIC PTHREAD_MAGIC+4
#define PTHREAD_COND_MAGIC PTHREAD_MAGIC+5
#define PTHREAD_CONDATTR_MAGIC PTHREAD_MAGIC+6
#define SEM_MAGIC PTHREAD_MAGIC+7
#define PTHREAD_ONCE_MAGIC PTHREAD_MAGIC+8
#define PTHREAD_RWLOCK_MAGIC PTHREAD_MAGIC+9
#define PTHREAD_RWLOCKATTR_MAGIC PTHREAD_MAGIC+10
#define PTHREAD_SPINLOCK_MAGIC PTHREAD_MAGIC+11

#define MUTEX_OWNER_ANONYMOUS ((pthread_t) -1)

typedef uint32_t thread_magic_t;

/* verifyable_object should not be defined here - it's a general purpose class */

class verifyable_object
{
public:
  thread_magic_t magic;

  verifyable_object (thread_magic_t verifyer): magic (verifyer) {}
  virtual ~verifyable_object () { magic = 0; }
};

typedef enum
{
  VALID_OBJECT,
  INVALID_OBJECT,
  VALID_STATIC_OBJECT
} verifyable_object_state;

template <class list_node> inline void
List_insert (list_node *&head, list_node *node)
{
  if (!node)
    return;
  do
    node->next = head;
  while (InterlockedCompareExchangePointer ((PVOID volatile *) &head,
					    node, node->next) != node->next);
}

template <class list_node> inline void
List_remove (fast_mutex &mx, list_node *&head, list_node *node)
{
  if (!node)
    return;
  mx.lock ();
  if (head)
    {
      if (InterlockedCompareExchangePointer ((PVOID volatile *) &head,
					     node->next, node) != node)
	{
	  list_node *cur = head;

	  while (cur->next && node != cur->next)
	    cur = cur->next;
	  if (node == cur->next)
	    cur->next = cur->next->next;
	}
    }
  mx.unlock ();
}


template <class list_node> class List
{
 public:
  List() : head(NULL)
  {
    mx_init ();
  }

  ~List()
  {
  }

  void fixup_after_fork ()
  {
    mx_init ();
  }

  void insert (list_node *node)
  {
    List_insert (head, node);
  }

  void remove (list_node *node)
  {
    List_remove (mx, head, node);
  }

  void for_each (void (list_node::*callback) ())
  {
    mx.lock ();
    list_node *cur = head;
    while (cur)
      {
	(cur->*callback) ();
	cur = cur->next;
      }
    mx.unlock ();
  }

  fast_mutex mx;
  list_node *head;

protected:
  void mx_init ()
  {
    if (!mx.init ())
      api_fatal ("Could not create mutex for list synchronisation.");
  }
};

class pthread_key: public verifyable_object
{
  DWORD tls_index;
public:
  static bool is_good_object (pthread_key_t const *);

  int set (const void *value) {TlsSetValue (tls_index, (void *) value); return 0;}
  void *get () const {return TlsGetValue (tls_index);}

  pthread_key (void (*)(void *));
  ~pthread_key ();
  static void fixup_before_fork ()
  {
    keys.for_each (&pthread_key::_fixup_before_fork);
  }

  static void fixup_after_fork ()
  {
    keys.fixup_after_fork ();
    keys.for_each (&pthread_key::_fixup_after_fork);
  }

  static void run_all_destructors ()
  {
    keys.for_each (&pthread_key::run_destructor);
  }

  /* List support calls */
  class pthread_key *next;
private:
  static List<pthread_key> keys;
  void _fixup_before_fork ();
  void _fixup_after_fork ();
  void (*destructor) (void *);
  void run_destructor ();
  void *fork_buf;
};

class pthread_attr: public verifyable_object
{
public:
  static bool is_good_object(pthread_attr_t const *);
  int joinable;
  int contentionscope;
  int inheritsched;
  struct sched_param schedparam;
  void *stackaddr;
  size_t stacksize;
  size_t guardsize;

  pthread_attr ();
  ~pthread_attr ();
};

class pthread_mutexattr: public verifyable_object
{
public:
  static bool is_good_object(pthread_mutexattr_t const *);
  int pshared;
  int mutextype;
  pthread_mutexattr ();
  ~pthread_mutexattr ();
};

class pthread_mutex: public verifyable_object
{
public:
  static void init_mutex ();
  static int init (pthread_mutex_t *, const pthread_mutexattr_t *attr,
		   const pthread_mutex_t);
  static bool is_good_object (pthread_mutex_t const *);
  static bool is_initializer (pthread_mutex_t const *);
  static bool is_initializer_or_object (pthread_mutex_t const *);
  static bool is_initializer_or_bad_object (pthread_mutex_t const *);

  int lock ();
  int trylock ();
  int unlock ();
  int destroy ();
  void set_type (int in_type) {type = in_type;}

  int lock_recursive ()
  {
    if (recursion_counter == UINT_MAX)
      return EAGAIN;
    recursion_counter++;
    return 0;
  }

  bool can_be_unlocked ();

  pthread_mutex (pthread_mutexattr * = NULL);
  pthread_mutex (pthread_mutex_t *, pthread_mutexattr *);
  ~pthread_mutex ();

  class pthread_mutex *next;
  static void fixup_after_fork ()
  {
    mutexes.fixup_after_fork ();
    mutexes.for_each (&pthread_mutex::_fixup_after_fork);
  }

protected:
  LONG lock_counter;
  HANDLE win32_obj_id;
  pthread_t owner;
#ifdef DEBUGGING
  DWORD tid;		/* the thread id of the owner */
#endif

  void set_shared (int in_shared) { pshared = in_shared; }
  void set_owner (pthread_t self)
  {
    recursion_counter = 1;
    owner = self;
#ifdef DEBUGGING
    tid = GetCurrentThreadId ();
#endif
  }

  static const pthread_t _new_mutex;
  static const pthread_t _unlocked_mutex;
  static const pthread_t _destroyed_mutex;

private:
  unsigned int recursion_counter;
  LONG condwaits;
  int type;
  int pshared;

  bool no_owner ();
  void _fixup_after_fork ();

  static List<pthread_mutex> mutexes;
  static fast_mutex mutex_initialization_lock;
  friend class pthread_cond;
};

class pthread_spinlock: public pthread_mutex
{
public:
  static bool is_good_object (pthread_spinlock_t const *);
  static int init (pthread_spinlock_t *, int);

  int lock ();
  int unlock ();

  pthread_spinlock (int);
};

class _cygtls;
class pthread: public verifyable_object
{
public:
  HANDLE win32_obj_id;
  class pthread_attr attr;
  void *(*function) (void *);
  void *arg;
  void *return_ptr;
  bool valid;
  bool suspended;
  bool canceled;
  int cancelstate, canceltype;
  _cygtls *cygtls;
  HANDLE cancel_event;
  pthread_t joiner;

  virtual bool create (void *(*)(void *), pthread_attr *, void *);

  pthread ();
  virtual ~pthread ();

  static void init_mainthread ();
  static bool is_good_object(pthread_t const *);
  static void atforkprepare();
  static void atforkparent();
  static void atforkchild();

  /* API calls */
  static int cancel (pthread_t);
  static int join (pthread_t * thread, void **return_val);
  static int detach (pthread_t * thread);
  static int create (pthread_t * thread, const pthread_attr_t * attr,
			      void *(*start_routine) (void *), void *arg);
  static int once (pthread_once_t *, void (*)(void));
  static int atfork(void (*)(void), void (*)(void), void (*)(void));
  static int suspend (pthread_t * thread);
  static int resume (pthread_t * thread);

  virtual void exit (void *value_ptr) __attribute__ ((noreturn));

  virtual int cancel ();

  virtual void testcancel ();
  static HANDLE get_cancel_event ();
  static void static_cancel_self () __attribute__ ((noreturn));

  virtual int setcancelstate (int state, int *oldstate);
  virtual int setcanceltype (int type, int *oldtype);

  virtual void push_cleanup_handler (__pthread_cleanup_handler *handler);
  virtual void pop_cleanup_handler (int const execute);

  static pthread* self ();
  static DWORD WINAPI thread_init_wrapper (void *);

  virtual unsigned long getsequence_np();

  static int equal (pthread_t t1, pthread_t t2)
  {
    return t1 == t2;
  }

  /* List support calls */
  class pthread *next;
  static void fixup_after_fork ()
  {
    threads.fixup_after_fork ();
    threads.for_each (&pthread::_fixup_after_fork);
  }

  static void suspend_all_except_self ()
  {
    threads.for_each (&pthread::suspend_except_self);
  }

  static void resume_all ()
  {
    threads.for_each (&pthread::resume);
  }

private:
  static List<pthread> threads;
  DWORD thread_id;
  __pthread_cleanup_handler *cleanup_stack;
  pthread_mutex mutex;
  sigset_t parent_sigmask;

  void suspend_except_self ();
  void resume ();

  void _fixup_after_fork ();

  void pop_all_cleanup_handlers ();
  void precreate (pthread_attr *);
  void postcreate ();
  bool create_cancel_event ();
  void set_tls_self_pointer ();
  void cancel_self () __attribute__ ((noreturn));
  DWORD get_thread_id ();
};

class pthread_null : public pthread
{
  public:
  static pthread *get_null_pthread();
  ~pthread_null();

  /* From pthread These should never get called
  * as the ojbect is not verifyable
  */
  bool create (void *(*)(void *), pthread_attr *, void *);
  void exit (void *value_ptr) __attribute__ ((noreturn));
  int cancel ();
  void testcancel ();
  int setcancelstate (int state, int *oldstate);
  int setcanceltype (int type, int *oldtype);
  void push_cleanup_handler (__pthread_cleanup_handler *handler);
  void pop_cleanup_handler (int const execute);
  unsigned long getsequence_np();

  private:
  pthread_null ();
  static pthread_null _instance;
};

class pthread_condattr: public verifyable_object
{
public:
  static bool is_good_object(pthread_condattr_t const *);
  int shared;
  clockid_t clock_id;

  pthread_condattr ();
  ~pthread_condattr ();
};

class pthread_cond: public verifyable_object
{
public:
  static bool is_good_object (pthread_cond_t const *);
  static bool is_initializer (pthread_cond_t const *);
  static bool is_initializer_or_object (pthread_cond_t const *);
  static bool is_initializer_or_bad_object (pthread_cond_t const *);
  static void init_mutex ();
  static int init (pthread_cond_t *, const pthread_condattr_t *);

  int shared;
  clockid_t clock_id;

  LONG waiting;
  LONG pending;
  HANDLE sem_wait;

  pthread_mutex mtx_in;
  pthread_mutex mtx_out;

  pthread_mutex_t mtx_cond;

  void unblock (const bool all);
  int wait (pthread_mutex_t mutex, PLARGE_INTEGER timeout = NULL);

  pthread_cond (pthread_condattr *);
  ~pthread_cond ();

  class pthread_cond * next;
  static void fixup_after_fork ()
  {
    conds.fixup_after_fork ();
    conds.for_each (&pthread_cond::_fixup_after_fork);
  }

private:
  void _fixup_after_fork ();

  static List<pthread_cond> conds;
  static fast_mutex cond_initialization_lock;
};

class pthread_rwlockattr: public verifyable_object
{
public:
  static bool is_good_object(pthread_rwlockattr_t const *);
  int shared;

  pthread_rwlockattr ();
  ~pthread_rwlockattr ();
};

class pthread_rwlock: public verifyable_object
{
public:
  static bool is_good_object (pthread_rwlock_t const *);
  static bool is_initializer (pthread_rwlock_t const *);
  static bool is_initializer_or_object (pthread_rwlock_t const *);
  static bool is_initializer_or_bad_object (pthread_rwlock_t const *);
  static void init_mutex ();
  static int init (pthread_rwlock_t *, const pthread_rwlockattr_t *);

  int shared;

  uint32_t waiting_readers;
  uint32_t waiting_writers;
  pthread_t writer;
  struct RWLOCK_READER
  {
    struct RWLOCK_READER *next;
    pthread_t thread;
    uint32_t n;
    RWLOCK_READER (): next (NULL), thread (pthread::self ()), n (0) {}
  } *readers;
  fast_mutex readers_mx;

  int rdlock ();
  int tryrdlock ();

  int wrlock ();
  int trywrlock ();

  int unlock ();

  pthread_mutex mtx;
  pthread_cond cond_readers;
  pthread_cond cond_writers;

  pthread_rwlock (pthread_rwlockattr *);
  ~pthread_rwlock ();

  class pthread_rwlock * next;
  static void fixup_after_fork ()
  {
    rwlocks.fixup_after_fork ();
    rwlocks.for_each (&pthread_rwlock::_fixup_after_fork);
  }

private:
  static List<pthread_rwlock> rwlocks;

  RWLOCK_READER *add_reader ();
  void remove_reader (struct RWLOCK_READER *rd);
  struct RWLOCK_READER *lookup_reader ();

  void release ()
  {
    if (waiting_writers)
      {
	if (!readers)
	  cond_writers.unblock (false);
      }
    else if (waiting_readers)
      cond_readers.unblock (true);
  }


  static void rdlock_cleanup (void *arg);
  static void wrlock_cleanup (void *arg);

  void _fixup_after_fork ();

  static fast_mutex rwlock_initialization_lock;
};

class pthread_once
{
public:
  pthread_mutex_t mutex;
  int state;
};

/* shouldn't be here */
class semaphore: public verifyable_object
{
public:
  static bool is_good_object(sem_t const *);
  /* API calls */
  static int init (sem_t *sem, int pshared, unsigned int value);
  static int destroy (sem_t *sem);
  static sem_t *open (unsigned long long hash, LUID luid, int fd, int oflag,
		      mode_t mode, unsigned int value, bool &wasopen);
  static int close (sem_t *sem);
  static int wait (sem_t *sem);
  static int post (sem_t *sem);
  static int getvalue (sem_t *sem, int *sval);
  static int trywait (sem_t *sem);
  static int timedwait (sem_t *sem, const struct timespec *abstime);

  static int getinternal (sem_t *sem, int *sfd, unsigned long long *shash,
			  LUID *sluid, unsigned int *sval);

  HANDLE win32_obj_id;
  int shared;
  LONG currentvalue;
  LONG startvalue;
  int fd;
  unsigned long long hash;
  LUID luid;
  sem_t *sem;

  semaphore (int, unsigned int);
  semaphore (unsigned long long, LUID, int, sem_t *, int, mode_t, unsigned int);
  ~semaphore ();

  class semaphore * next;
  static void fixup_before_fork ()
  {
    semaphores.for_each (&semaphore::_fixup_before_fork);
  }
  static void fixup_after_fork ()
  {
    semaphores.fixup_after_fork ();
    semaphores.for_each (&semaphore::_fixup_after_fork);
  }
  static void terminate ()
  {
    save_errno save;
    semaphores.for_each (&semaphore::_terminate);
  }

private:
  int _wait ();
  void _post ();
  int _getvalue (int *sval);
  int _trywait ();
  int _timedwait (const struct timespec *abstime);

  void _fixup_before_fork ();
  void _fixup_after_fork ();
  void _terminate ();

  static List<semaphore> semaphores;
};

class callback
{
public:
  void (*cb)(void);
  class callback * next;
};

struct MTinterface
{
  // General
  int concurrency;
  LONG threadcount;

  callback *pthread_prepare;
  callback *pthread_child;
  callback *pthread_parent;

  void Init ();
  void fixup_before_fork ();
  void fixup_after_fork ();

#if 0 // avoid initialization since zero is implied and
  MTinterface () :
    concurrency (0), threadcount (0),
    pthread_prepare (NULL), pthread_child (NULL), pthread_parent (NULL)
  {
  }
#endif
};

#define MT_INTERFACE user_data->threadinterface