Implement fhandler reference counting.

* cygheap.h
(cygheap_fdmanip::release): Make virtual.
(cygheap_fdnew::~cygheap_fdnew): New destructor increments reference count when
fd has been allocated.
(cygheap_fdget::fh): New (old?) field.
(cygheap_fdget::cygheap_fdget): Increment reference count when we've found an
active fd.  Set fh appropriately.
(cygheap_fdget::~cygheap_fdget): Decrement reference count when appropriate.
Delete fh if reference count goes to zero.
(cygheap_fdget::release): New function.  Do more bookkeping on release.
* dtable.cc (dtable::release): Change from void to boolean return.  Only delete
the fhandler when its reference count is <= 0 (this should be a fairly unusual
case).  Return true if fhandler has been deleted.
(cygwin_attach_handle_to_fd): Increment reference count when fh is assigned.
(dtable::init_std_file_from_handle): Ditto.
* dtable.h (dtable::release): Change return to boolean.
* fhandler.cc (fhandler_base::fhandler_base): Set new isclosed flag to false.
Set _refcnt to zero.
(fhandler_base::close): Simplify paranoid debugging output.  Set new isclosed()
flag.
(fhandler_base_overlapped::wait_overlapped): Use isclosed() flag to avoid
querying the exception handle.
* fhandler.h (fhandler_base::_refcnt): New field.
(fhandler_base::refcnt): New function.
(fhandler_base::isclosed): Implement.
(fhandler_base::fhandler_base): Set isclosed to false.
* syscalls.cc: Remove space after function before parentheses for several
strace printfs.
(dup): Add standard strace "leaver" code.
(dup2): Ditto.
(dup3): Ditto.
(remove): Ditto.
(getpid): Ditto.
(getppid): Ditto.
(lseek64): Fix strace debugging to correctly use %R.
* fhandler_termios.cc (fhandler_termios::tcsetpgrp): Avoid sending signals to
other processes if we're debugging since it can cause a deadlock with the
calling debugger.
* exceptions.cc (_cygtls::call_signal_handler): Add debugging-only strace
output.

1 files changed, 29 insertions, 5 deletions

diff --git a/winsup/cygwin/cygheap.h b/winsup/cygwin/cygheap.h
index 204ebe2f8..5d7b93dcc 100644
--- a/winsup/cygwin/cygheap.h
+++ b/winsup/cygwin/cygheap.h
@@ -328,10 +328,7 @@ class cygheap_fdmanip
     if (locked)
       cygheap->fdtab.unlock ();
   }
-  void release ()
-  {
-    cygheap->fdtab.release (fd);
-  }
+  virtual void release () { cygheap->fdtab.release (fd); }
   operator int &() {return fd;}
   operator fhandler_base* &() {return cygheap->fdtab[fd];}
   operator fhandler_socket* () const {return reinterpret_cast<fhandler_socket *> (cygheap->fdtab[fd]);}
@@ -368,12 +365,18 @@ class cygheap_fdnew : public cygheap_fdmanip
 	locked = false;
       }
   }
+  ~cygheap_fdnew ()
+  {
+    if (cygheap->fdtab[fd])
+      cygheap->fdtab[fd]->refcnt (1);
+  }
   void operator = (fhandler_base *fh) {cygheap->fdtab[fd] = fh;}
 };
 
 class cygheap_fdget : public cygheap_fdmanip
 {
- public:
+  fhandler_base *fh;
+public:
   cygheap_fdget (int fd, bool lockit = false, bool do_set_errno = true)
   {
     if (lockit)
@@ -382,6 +385,8 @@ class cygheap_fdget : public cygheap_fdmanip
       {
 	this->fd = fd;
 	locked = lockit;
+	fh = cygheap->fdtab[fd];
+	fh->refcnt (1);
       }
     else
       {
@@ -391,8 +396,27 @@ class cygheap_fdget : public cygheap_fdmanip
 	if (lockit)
 	  cygheap->fdtab.unlock ();
 	locked = false;
+	fh = NULL;
       }
   }
+  ~cygheap_fdget ()
+  {
+    if (!fh)
+      /* nothing to do */;
+    else if (fh->refcnt (-1) > 0)
+      debug_only_printf ("fh %p, %s, refcnt %ld", fh, fh->get_name (), fh->refcnt ());
+    else
+      {
+	debug_only_printf ("deleting fh %p, %s, refcnt %ld", fh, fh->get_name (), fh->refcnt ());
+	delete fh;
+      }
+  }
+  void release ()
+  {
+    fh = cygheap->fdtab[fd];
+    if (cygheap->fdtab.release (fd))
+      fh = NULL;
+  }
 };
 
 class cygheap_fdenum : public cygheap_fdmanip