Tue Sep 11 18:15:00 2001 Robert Collins <rbtcollins@hotmail.com>

        * dcrt0.cc (cygwin_finished_initializing): Copy _mtinterf on fork;
        * fork.cc (fork_child): fixup thread-related structures after fork;
        * thread.cc (MTinterface::Init): Initialise the new mutex, condition and semaphore lists.
        (MTinterface::fixup_after_fork): Iterate through each list and fixup the objects.
        (pthread_cond::pthread_cond): Add this to the condition list.
        (pthread_cond::~pthread_cond): Remove this from the condition list.
        (pthread_cond::fixup_after_fork): Recreate as best we can the pre-fork state.
        (pthread_mutex::pthread_mutex): Add this to the mutex list.
        (pthread_mutex::~pthread_mutex): Remove this from the mutex list.
        (pthread_mutex::fixup_after_fork): Recreate as best we can the pre-fork state.
        (semaphore::semaphore): Store the initial value, and add this to the semaphore list.
        (semaphore::~semaphore): Remove this from the semaphore list.
        (semaphore::Post): Increment the current semaphore value.
        (semaphore::TryWait): Decrement the current semaphore value.
        (semaphore::Wait): Ditto.
        (semaphote::fixup_after_fork): Recreate the pre-fork state as best we can.
        * thread.h (pthread_mutex): New members to allow fixup_after_fork.
        (pthread_cond): Ditto.
        (semaphore): Ditto.
        (MTinterface): New list heads for tracking conds and semaphores.

5 files changed, 162 insertions, 11 deletions

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 6bdc2fa..8474745 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,26 @@
+Tue Sep 11 18:15:00 2001  Robert Collins <rbtcollins@hotmail.com>
+
+	* dcrt0.cc (cygwin_finished_initializing): Copy _mtinterf on fork;
+	* fork.cc (fork_child): fixup thread-related structures after fork;
+	* thread.cc (MTinterface::Init): Initialise the new mutex, condition and semaphore lists.
+	(MTinterface::fixup_after_fork): Iterate through each list and fixup the objects.
+	(pthread_cond::pthread_cond): Add this to the condition list.
+	(pthread_cond::~pthread_cond): Remove this from the condition list.
+	(pthread_cond::fixup_after_fork): Recreate as best we can the pre-fork state.
+	(pthread_mutex::pthread_mutex): Add this to the mutex list.
+	(pthread_mutex::~pthread_mutex): Remove this from the mutex list.
+	(pthread_mutex::fixup_after_fork): Recreate as best we can the pre-fork state.
+ 	(semaphore::semaphore): Store the initial value, and add this to the semaphore list.
+	(semaphore::~semaphore): Remove this from the semaphore list.
+	(semaphore::Post): Increment the current semaphore value.
+	(semaphore::TryWait): Decrement the current semaphore value.
+	(semaphore::Wait): Ditto.
+	(semaphote::fixup_after_fork): Recreate the pre-fork state as best we can.
+	* thread.h (pthread_mutex): New members to allow fixup_after_fork.
+	(pthread_cond): Ditto.
+	(semaphore): Ditto.
+	(MTinterface): New list heads for tracking conds and semaphores.
+
 Sun Sep  9 22:11:27 2001  Christopher Faylor <cgf@cygnus.com>
 
 	* dtable.cc (dtable::fixup_after_fork): Use SetStdHandle appropriately
diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index 4f278ce..ef03386 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -70,7 +70,7 @@ int cygwin_finished_initializing;
 unsigned NO_COPY int signal_shift_subtract = 1;
 
 ResourceLocks _reslock NO_COPY;
-MTinterface _mtinterf NO_COPY;
+MTinterface _mtinterf;
 
 bool NO_COPY _cygwin_testing;
 
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc
index 3a63e39..ccfc2aa 100644
--- a/winsup/cygwin/fork.cc
+++ b/winsup/cygwin/fork.cc
@@ -309,6 +309,8 @@ fork_child (HANDLE& hParent, dll *&first_dll, bool& load_dlls)
     if ((*t)->clear_on_fork ())
       (*t)->set ();
 
+  user_data->threadinterface->fixup_after_fork ();
+
   /* Initialize signal/process handling */
   sigproc_init ();
   __pthread_atforkchild ();
diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index f05d441..c4d6c05 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -302,6 +302,10 @@ MTinterface::Init (int forked)
   if (forked)
     return;
 
+  mutexs = NULL;
+  conds  = NULL;
+  semaphores = NULL;
+
   /*possible the atfork lists should be inited here as well */
 
 #if 0
@@ -313,6 +317,33 @@ MTinterface::Init (int forked)
 #endif
 }
 
+/* This function is called from a single threaded process */
+void
+MTinterface::fixup_after_fork (void)
+{
+  pthread_mutex *mutex = mutexs;
+  debug_printf("mutexs is %x\n",mutexs);
+  while (mutex)
+    {
+      mutex->fixup_after_fork ();
+      mutex = mutex->next;
+    }
+  pthread_cond *cond = conds;
+  debug_printf("conds is %x\n",conds);
+  while (cond)
+    {
+      cond->fixup_after_fork ();
+      cond = cond->next;
+    }
+  semaphore *sem = semaphores;
+  debug_printf("semaphores is %x\n",semaphores);
+  while (sem)
+    {
+      sem->fixup_after_fork ();
+      sem = sem->next;
+    }
+}
+
 pthread::pthread ():verifyable_object (PTHREAD_MAGIC), win32_obj_id (0),
 cancelstate (0), canceltype (0)
 {
@@ -402,6 +433,8 @@ pthread_cond::pthread_cond (pthread_condattr *attr):verifyable_object (PTHREAD_C
 
   if (!this->win32_obj_id)
     magic = 0;
+  /* threadsafe addition is easy */
+  next = (pthread_cond *)InterlockedExchangePointer (&MT_INTERFACE->conds, this);
 }
 
 pthread_cond::~pthread_cond ()
@@ -409,6 +442,17 @@ pthread_cond::~pthread_cond ()
   if (win32_obj_id)
     CloseHandle (win32_obj_id);
   pthread_mutex_destroy (&cond_access);
+  /* I'm not 100% sure the next bit is threadsafe. I think it is... */
+  if (MT_INTERFACE->conds == this)
+    MT_INTERFACE->conds = (pthread_cond *)InterlockedExchangePointer (&MT_INTERFACE->conds, this->next);
+  else
+    {
+      pthread_cond *tempcond = MT_INTERFACE->conds;
+      while (tempcond->next && tempcond->next != this)
+        tempcond = tempcond->next;
+      /* but there may be a race between the loop above and this statement */
+      tempcond->next = (pthread_cond *)InterlockedExchangePointer (&tempcond->next, this->next);
+    }
 }
 
 void
@@ -478,6 +522,21 @@ pthread_cond::TimedWait (DWORD dwMilliseconds)
     }
 }
 
+void
+pthread_cond::fixup_after_fork ()
+{
+  debug_printf("cond %x in fixup_after_fork\n", this);
+  if (shared != PTHREAD_PROCESS_PRIVATE)
+    api_fatal("doesn't understand PROCESS_SHARED condition variables\n");
+  /* FIXME: duplicate code here and in the constructor. */
+  this->win32_obj_id =::CreateEvent (&sec_none_nih, false, false, NULL);
+  if (!win32_obj_id)
+    api_fatal("failed to create new win32 mutex\n");
+  if (waiting)
+    api_fatal("Forked() while a condition variable has waiting threads.\nReport to cygwin@cygwin.com\n");
+}
+
+
 pthread_key::pthread_key (void (*destructor) (void *)):verifyable_object (PTHREAD_KEY_MAGIC)
 {
   dwTlsIndex = TlsAlloc ();
@@ -536,6 +595,13 @@ pthread_key::get ()
  *Isn't duplicated, it's reopened.
  */
 
+/*FIXME: implement InterlockExchangePointer and get rid of the silly typecasts in pthread_atfork
+ */
+#ifndef InterlockedExchangePointer
+#define InterlockedExchangePointer InterlockedExchange
+#endif
+ 
+
 pthread_mutex::pthread_mutex (pthread_mutexattr *attr):verifyable_object (PTHREAD_MUTEX_MAGIC)
 {
   /*attr checked in the C call */
@@ -552,6 +618,8 @@ pthread_mutex::pthread_mutex (pthread_mutexattr *attr):verifyable_object (PTHREA
     magic = 0;
   condwaits = 0;
   pshared = PTHREAD_PROCESS_PRIVATE;
+  /* threadsafe addition is easy */
+  next = (pthread_mutex *)InterlockedExchangePointer (&MT_INTERFACE->mutexs, this);
 }
 
 pthread_mutex::~pthread_mutex ()
@@ -559,6 +627,17 @@ pthread_mutex::~pthread_mutex ()
   if (win32_obj_id)
     CloseHandle (win32_obj_id);
   win32_obj_id = NULL;
+  /* I'm not 100% sure the next bit is threadsafe. I think it is... */
+  if (MT_INTERFACE->mutexs == this)
+    MT_INTERFACE->mutexs = (pthread_mutex *)InterlockedExchangePointer (&MT_INTERFACE->mutexs, this->next);
+  else
+    {
+      pthread_mutex *tempmutex = MT_INTERFACE->mutexs;
+      while (tempmutex->next && tempmutex->next != this)
+	tempmutex = tempmutex->next;
+      /* but there may be a race between the loop above and this statement */
+      tempmutex->next = (pthread_mutex *)InterlockedExchangePointer (&tempmutex->next, this->next);
+    }
 }
 
 int
@@ -579,6 +658,21 @@ pthread_mutex::UnLock ()
   return ReleaseMutex (win32_obj_id);
 }
 
+void
+pthread_mutex::fixup_after_fork ()
+{
+  debug_printf("mutex %x in fixup_after_fork\n", this);
+  if (pshared != PTHREAD_PROCESS_PRIVATE)
+    api_fatal("pthread_mutex::fixup_after_fork () doesn'tunderstand PROCESS_SHARED mutex's\n");
+  /* FIXME: duplicate code here and in the constructor. */
+  this->win32_obj_id =::CreateMutex (&sec_none_nih, false, NULL);
+
+  if (!win32_obj_id)
+    api_fatal("pthread_mutex::fixup_after_fork() failed to create new win32 mutex\n");
+  if (condwaits)
+    api_fatal("Forked() while a mutex has condition variables waiting on it.\nReport to cygwin@cygwin.com\n");
+}
+
 pthread_mutexattr::pthread_mutexattr ():verifyable_object (PTHREAD_MUTEXATTR_MAGIC),
 pshared (PTHREAD_PROCESS_PRIVATE), mutextype (PTHREAD_MUTEX_DEFAULT)
 {
@@ -595,19 +689,34 @@ semaphore::semaphore (int pshared, unsigned int value):verifyable_object (SEM_MA
   if (!this->win32_obj_id)
     magic = 0;
   this->shared = pshared;
+  currentvalue = value;
+  /* threadsafe addition is easy */
+  next = (semaphore *)InterlockedExchangePointer (&MT_INTERFACE->semaphores, this);
 }
 
 semaphore::~semaphore ()
 {
   if (win32_obj_id)
     CloseHandle (win32_obj_id);
+  /* I'm not 100% sure the next bit is threadsafe. I think it is... */
+  if (MT_INTERFACE->semaphores == this)
+    MT_INTERFACE->semaphores = (semaphore *)InterlockedExchangePointer (&MT_INTERFACE->semaphores, this->next);
+  else
+    {
+      semaphore *tempsem = MT_INTERFACE->semaphores;
+      while (tempsem->next && tempsem->next != this)
+        tempsem = tempsem->next;
+      /* but there may be a race between the loop above and this statement */
+      tempsem->next = (semaphore *)InterlockedExchangePointer (&tempsem->next, this->next);
+    }
 }
 
 void
 semaphore::Post ()
 {
-  long pc;
-  ReleaseSemaphore (win32_obj_id, 1, &pc);
+  /* we can't use the currentvalue, because the wait functions don't let us access it */
+  ReleaseSemaphore (win32_obj_id, 1, NULL);
+  currentvalue++;
 }
 
 int
@@ -618,14 +727,27 @@ semaphore::TryWait ()
    */
   if (WaitForSingleObject (win32_obj_id, 0) == WAIT_TIMEOUT)
     return EAGAIN;
-  else
-    return 0;
+  currentvalue--;
+  return 0;
 }
 
 void
 semaphore::Wait ()
 {
   WaitForSingleObject (win32_obj_id, INFINITE);
+  currentvalue--;
+}
+
+void
+semaphore::fixup_after_fork ()
+{
+  debug_printf("sem %x in fixup_after_fork\n", this);
+  if (shared != PTHREAD_PROCESS_PRIVATE)
+    api_fatal("doesn't understand PROCESS_SHARED semaphores variables\n");
+  /* FIXME: duplicate code here and in the constructor. */
+  this->win32_obj_id =::CreateSemaphore (&sec_none_nih, currentvalue, LONG_MAX, NULL);
+  if (!win32_obj_id)
+    api_fatal("failed to create new win32 semaphore\n");
 }
 
 verifyable_object::verifyable_object (long verifyer):
@@ -1052,12 +1174,6 @@ __pthread_atforkchild (void)
     }
 }
 
-/*FIXME: implement InterlockExchangePointer and get rid of the silly typecasts below
- */
-#ifndef InterlockedExchangePointer
-#define InterlockedExchangePointer InterlockedExchange
-#endif
-
 /*Register a set of functions to run before and after fork.
  *prepare calls are called in LI-FC order.
  *parent and child calls are called in FI-FC order.
diff --git a/winsup/cygwin/thread.h b/winsup/cygwin/thread.h
index d027830..e810530 100644
--- a/winsup/cygwin/thread.h
+++ b/winsup/cygwin/thread.h
@@ -270,10 +270,12 @@ public:
   HANDLE win32_obj_id;
   LONG condwaits;
   int pshared;
+  class pthread_mutex * next;
 
   int Lock ();
   int TryLock ();
   int UnLock ();
+  void fixup_after_fork ();
 
   pthread_mutex (unsigned short);
   pthread_mutex (pthread_mutexattr *);
@@ -299,9 +301,11 @@ public:
   /* to allow atomic behaviour for cond_broadcast */
   pthread_mutex_t cond_access;
   HANDLE win32_obj_id;
+  class pthread_cond * next;
   int TimedWait (DWORD dwMilliseconds);
   void BroadCast ();
   void Signal ();
+  void fixup_after_fork ();
 
     pthread_cond (pthread_condattr *);
    ~pthread_cond ();
@@ -319,10 +323,13 @@ class semaphore:public verifyable_object
 {
 public:
   HANDLE win32_obj_id;
+  class semaphore * next;
   int shared;
+  long currentvalue;
   void Wait ();
   void Post ();
   int TryWait ();
+  void fixup_after_fork ();
 
     semaphore (int, unsigned int);
    ~semaphore ();
@@ -358,8 +365,11 @@ public:
 
   // list of mutex's. USE THREADSAFE INSERTS AND DELETES.
   class pthread_mutex * mutexs;
+  class pthread_cond  * conds;
+  class semaphore     * semaphores;
 
   void Init (int);
+  void fixup_after_fork (void);
 
     MTinterface ():reent_index (0), indexallocated (0), threadcount (1)
   {