* fork.cc (fork_child): Call the __pthread_atforkchild function.

(fork_parent): Call the __pthread_atforkparent function.
* cygwin.din: Export pthread_atfork.
* thread.h (callback): New class.
(MTinterface): Use it.
* thread.cc (__pthread_atforkprepare): New function.
(__pthread_atforkparent): New function.
(__pthread_atforkchild): New function.
(__pthread_atfork): New function.
* pthread.cc (pthread_atfork): New function.

7 files changed, 163 insertions, 4 deletions

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index f94ec6ed6..451a0c9b5 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,16 @@
+Fri Apr 13 2001  Robert Collins <rbtcollins@hotmail.com>
+
+	* fork.cc (fork_child): Call the __pthread_atforkchild function.
+	(fork_parent): Call the __pthread_atforkparent function.
+	* cygwin.din: Export pthread_atfork.
+	* thread.h (callback): New class.
+	(MTinterface): Use it.
+	* thread.cc (__pthread_atforkprepare): New function.
+	(__pthread_atforkparent): New function.
+	(__pthread_atforkchild): New function.
+	(__pthread_atfork): New function.
+	* pthread.cc (pthread_atfork): New function.
+
 Fri Apr 13  9:52:00 2001  Corinna Vinschen <corinna@vinschen.de>
 
 	* path.cc (add_ext_from_sym): New define evaluating `known'suffix'.
diff --git a/winsup/cygwin/cygwin.din b/winsup/cygwin/cygwin.din
index a94af5e2c..285f7249c 100644
--- a/winsup/cygwin/cygwin.din
+++ b/winsup/cygwin/cygwin.din
@@ -1076,6 +1076,7 @@ cygwin_attach_handle_to_fd
 cygwin32_attach_handle_to_fd = cygwin_attach_handle_to_fd
 cygwin_internal
 cygwin32_internal = cygwin_internal
+pthread_atfork
 pthread_attr_destroy
 pthread_attr_getdetachstate
 pthread_attr_getinheritsched
diff --git a/winsup/cygwin/fhandler.cc b/winsup/cygwin/fhandler.cc
index ff9a9dfb4..df2fd2217 100644
--- a/winsup/cygwin/fhandler.cc
+++ b/winsup/cygwin/fhandler.cc
@@ -370,9 +370,8 @@ fhandler_base::open (int flags, mode_t mode)
 		   file_attributes,
 		   0);
 
-  syscall_printf ("%d = CreateFileA (%s, %p, %p, %p, %p, %p, 0)",
-		  x,
-		  get_win32_name (), access_, shared,
+  syscall_printf ("%p = CreateFileA (%s, %p, %p, %p, %p, %p, 0)",
+		  x, get_win32_name (), access_, shared,
 		  &sec_none, creation_distribution,
 		  file_attributes);
 
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc
index 6d6f10b0c..de85c1d96 100644
--- a/winsup/cygwin/fork.cc
+++ b/winsup/cygwin/fork.cc
@@ -307,6 +307,7 @@ fork_child (HANDLE& hParent, dll *&first_dll, bool& load_dlls)
 
   /* Initialize signal/process handling */
   sigproc_init ();
+  __pthread_atforkchild();
   cygbench ("fork-child");
   return 0;
 }
@@ -597,6 +598,7 @@ out:
   ForceCloseHandle (forker_finished);
   forker_finished = NULL;
   pi.hThread = NULL;
+  __pthread_atforkparent();
 
   return forked->pid;
 
@@ -640,6 +642,9 @@ fork ()
       return -1;
     }
 
+  /* call the pthread_atfork prepare functions */
+  __pthread_atforkprepare();
+
   void *esp;
   __asm ("movl %%esp,%0": "=r" (esp));
 
diff --git a/winsup/cygwin/pthread.cc b/winsup/cygwin/pthread.cc
index c9f0bb2bf..74cce7c23 100644
--- a/winsup/cygwin/pthread.cc
+++ b/winsup/cygwin/pthread.cc
@@ -30,6 +30,12 @@ pthread_once (pthread_once_t * once_control, void (*init_routine) (void))
 }
 
 int
+pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void))
+{
+  return __pthread_atfork(prepare, parent, child);
+}
+
+int
 pthread_attr_init (pthread_attr_t * attr)
 {
   return __pthread_attr_init (attr);
diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index e870c3131..1bcfd4e4d 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -935,6 +935,124 @@ __pthread_testcancel (void)
    * does something*/
 }
 
+/*
+ * Races in pthread_atfork:
+ * We are race safe in that any additions to the lists are made via 
+ * InterlockedExchangePointer.
+ * However, if the user application doesn't perform syncronisation of some sort
+ * It's not guaranteed that a near simultaneous call to pthread_atfork and fork 
+ * will result in the new atfork handlers being calls.
+ * More rigorous internal syncronisation isn't needed as the user program isn't 
+ * guaranteeing their own state. 
+ *
+ * as far as multiple calls to pthread_atfork, the worst case is simultaneous calls
+ * will result in an indeterminate order for parent and child calls (what gets inserted
+ * first isn't guaranteed.)
+ *
+ * There is one potential race... Does the result of InterlockedExchangePointer 
+ * get committed to the return location _before_ any context switches can occur?
+ * If yes, we're safe, if no, we're not.
+ */
+void
+__pthread_atforkprepare(void)
+{
+  callback *cb=MT_INTERFACE->pthread_prepare;
+  while (cb)
+    {
+      cb->cb();
+      cb=cb->next;
+    }
+}
+
+void 
+__pthread_atforkparent(void)
+{
+  callback *cb=MT_INTERFACE->pthread_parent;
+  while (cb)
+    {
+      cb->cb();
+      cb=cb->next;
+    }
+}
+
+void
+__pthread_atforkchild(void)
+{
+  callback *cb=MT_INTERFACE->pthread_child;
+  while (cb)
+    {
+      cb->cb();
+      cb=cb->next;
+    }
+}
+
+/* FIXME: implement InterlockExchangePointer and get rid of the silly typecasts below
+ */
+#define InterlockedExchangePointer InterlockedExchange
+
+/* 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.
+ */
+int
+__pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void))
+{
+  callback * prepcb=NULL, * parentcb=NULL, * childcb=NULL;
+  if (prepare)
+    {
+      prepcb = new callback;
+      if (!prepcb)
+	return ENOMEM;
+    }
+  if (parent)
+    {
+      parentcb = new callback;
+      if (!parentcb)
+	{
+	  if (prepcb)
+	    delete prepcb;
+	  return ENOMEM;
+	}
+    }
+  if (child)
+    {
+      childcb = new callback;
+      if (!childcb)
+	{
+	  if (prepcb)
+	    delete prepcb;
+	  if (parentcb)
+	    delete parentcb;
+	  return ENOMEM;
+	}
+    }
+
+  if (prepcb)
+  {
+    prepcb->cb = prepare;
+    prepcb->next=(callback *)InterlockedExchangePointer((LONG *) &MT_INTERFACE->pthread_prepare, (long int) prepcb);
+  }
+  if (parentcb)
+  {
+    parentcb->cb = parent;
+    callback ** t = &MT_INTERFACE->pthread_parent;
+    while (*t)
+      t = &(*t)->next;
+    /* t = pointer to last next in the list */
+    parentcb->next=(callback *)InterlockedExchangePointer((LONG *)t, (long int) parentcb);
+  }
+  if (childcb)
+  {
+    childcb->cb = child;
+    callback ** t = &MT_INTERFACE->pthread_child;
+    while (*t)
+      t = &(*t)->next;
+    /* t = pointer to last next in the list */
+    childcb->next=(callback *)InterlockedExchangePointer((LONG *)t, (long int) childcb);
+  }
+  return 0;
+}
+
 int
 __pthread_attr_init (pthread_attr_t * attr)
 {
diff --git a/winsup/cygwin/thread.h b/winsup/cygwin/thread.h
index 00c10b298..2b6e7d7e7 100644
--- a/winsup/cygwin/thread.h
+++ b/winsup/cygwin/thread.h
@@ -317,6 +317,13 @@ public:
    ~semaphore ();
 };
 
+class callback
+{
+public:
+  void (*cb)(void);
+  class callback * next;
+};
+
 class MTinterface
 {
 public:
@@ -333,14 +340,23 @@ public:
   pthread mainthread;
 
   pthread_key_destructor_list destructors;
+  callback *pthread_prepare;
+  callback *pthread_child;
+  callback *pthread_parent;
 
   void Init (int);
 
-    MTinterface ():reent_index (0), indexallocated (0)
+    MTinterface ():reent_index (0), indexallocated (0) 
   {
+    pthread_prepare = NULL;
+    pthread_child   = NULL;
+    pthread_parent  = NULL;
   }
 };
 
+void __pthread_atforkprepare(void);
+void __pthread_atforkparent(void);
+void __pthread_atforkchild(void);
 
 extern "C"
 {
@@ -350,6 +366,7 @@ void *thread_init_wrapper (void *);
 int __pthread_create (pthread_t * thread, const pthread_attr_t * attr,
 		      void *(*start_routine) (void *), void *arg);
 int __pthread_once (pthread_once_t *, void (*)(void));
+int __pthread_atfork(void (*)(void), void (*)(void), void (*)(void));
 
 int __pthread_attr_init (pthread_attr_t * attr);
 int __pthread_attr_destroy (pthread_attr_t * attr);