2002-02-28 Robert Collins <rbtcollins@hotmail.com>

	* Merged cygwin_daemon into head minus the new shm and ipc exports.

2002-02-28  Robert Collins  <rbtcollins@hotmail.com>

	* fhandler_tty.cc (fhandler_tty_slave::open): More debugging.
	(fhandler_tty_slave::read): Fix printf type for the handle.
	* tty.cc (tty::common_init): Add a FIXME for security.

2002-01-29  Robert Collins  <rbtcollins@hotmail.com>

	* Makefile.in (OBJS): Remove duplicate localtime.o.

2002-01-17  Robert Collins  <rbtcollins@hotmail.com>

	* cygserver.cc (check_and_dup_handle): Consolidate the two variants for
	simplicity.
	Add Some basic debug output.
	(client_request_attach_tty::serve): Use the new debug_printf for clarity.
	Mark the duplicated handles as inheritable - fixup_after_fork() doesn't reopen
	tty's.

2002-01-16  Robert Collins  <rbtcollins@hotmail.com>

	* cygserver.cc (transport): Correct scope.
	(client_request_attach_tty::serve): Add more debug information.
	Fix erroneous use of transport instead of conn.
	* cygserver_transport_pipes.cc (transport_layer_pipes::close): More debug.
	(transport_layer_pipes::read): Ditto.
	(transport_layer_pipes::write): Ditto.
	(transport_layer_pipes::impersonate_client): Ditto.

Mon Oct  8  7:41:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* cygserver.cc (server_request::process): Rename client_request_shm_get to
	client_request_shm.
	* cygserver_process.cc (process_cache::add): Rename to add_task.
	Use process_cleanup instead of process_request.
	(process_cache::remove_process): New method.
	(process::process): Initialize new members.
	(process::~process): New member.
	(process::cleanup): New method.
	(process::add_cleanup_routine): New method.
	(process_request::process): Rename to process_cleanup.
	Call the process object's cleanup method and then delete it.
	(process_process_param::request_loop): Remove the signalling process.
	* cygserver_shm.cc: Globally rename client_request_shm_get to client_request_shm.
	(client_request_shm_get::serve): Handle attach request counting.
	* cygserver_shm.h: Globally rename client_request_shm_get to client_request_shm.
	(class shm_cleanup): New class.
	* shm.cc: Globally rename client_request_shm_get to client_request_shm.
	(client_request_shm::client_request_shm): New constructor for attach requests.
	(shmat): Use it.
	* include/cygwin/cygserver_process.h (class process_request): Rename to
	process_cleanup.
	(class cleanup_routine): New class.
	(class process): New members and methods to allow calling back when the process
	terminates.

Thu Oct  4 14:12:00 2001  Robert Collins <rbtcollins@hotmail.com>
	* cygserver.cc (request_loop): Make static.
	(main): Use new cache constructor syntax.
	Start cache worker threads.
	Cleanup the cache at shutdown.
	* cygserver_process.cc: Run indent.
	(process_cache::process_cache): Add a trigger to use when adding a process.
	(process_cache::process): Move process_entry to process.
	Insert at the end of the list.
	Trigger the request loop when new process's inserted.
	(process_cache::process_requests): Do it.
	(process_cache::add): New method.
	(process_cache::handle_snapshot): New method.
	(process::process): Merge in the process_entry fields.
	(process::handle): Make a stub function.
	(process::exit_code): New method.
	(process_request::process): New method.
	(process_process_param::request_loop): New method.
	* cygserver_shm.cc: New header dependency - threaded_queue.h.
	* threaded_queue.cc (threaded_queue::cleanup): Clearer messages.
	(queue_process_param::stop): Short spinlock on interruptible threads.
	* threaded_queue.h (class threaded_queue): New constructor.
	* include/cygwin/cygserver_process.h (process_request): New class.
	(process_entry): Remove.
	(process): Merge in process_entry.
	(process_cache): Inherit from threaded_queue.

Tue Oct  2 23:24:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* cygserver.cc (class server_process_param): Use new constructor syntax.
	* cygserver_process.cc (process_cache::~process_cache): New function.
	* threaded_queue.cc: Define condition debug_printf.
	Run indent.
	(threaded_queue::cleanup): Move queue_process_param guts to a method.
	(threaded_queue::process_requests): Ditto.
	(queue_process_param::queue_process_param): New method.
	(queue_process_param::~queue_process_param): Ditto.
	(queue_process_param::start): Ditto.
	(queue_process_param::stop): Ditto.
	* threaded_queue.h (class queue_process_param): Add support for
	interruptible request loops.
	* cygwin/include/cygwin/cygserver_process.h (class process_cache): Add
	destructor.

Tue Oct  2 23:24:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* cygserver_client.cc: New flag allow_daemon to disable the daemon completely.
	(cygserver_request): Check it.
	(cygserver_init): Ditto.
	* environ.cc (parse_thing): Add (no)daemon option.

Tue Oct  2 23:00:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* shm.cc: Update to handle include changes from HEAD.

Tue Oct  2 16:06:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* Makefile.in: Remove cygserver_shm.o from cygwin1.dll.
	Rename cygserver_shm_outside.o to cygserver_shm.o.
	* cygserver.cc (server_request::process): Use the new client_request
	constructor.
	* cygserver_client.cc: Remove the #ifdef's stubs for the server method
	within cygwin.
	(client_request_attach_tty::client_request_attach_tty): Use the new
	client_request constructor.
	(client_request_shutdown::client_request_shutdown): Ditto.
	(client_request::client_request): Ditto.
	* cygserver_shm.cc (client_request_shm_get::serve): Remove the
	#ifdef'd stub for in-cygwin builds.
	(client_request_shm_get::client_request_shm_get): Use the new
	client_request constructor, and remove the in-cygwin variants.
	* cygserver_shm.h (class client_request_shm_get): #ifndef test the
	serve method - it's only used in cygserver.
	* shm.cc (client_request_shm_get::client_request_shm_get): New function.
	* include/cygwin/cygserver.h (request_header): New constructor.
	(class client_request): Use it.
	New constructor accepting the header size.
	#ifndef test the server method - it's only used within cygserver.
	(client_request_get_version): #ifdef test the server method.
	(client_request_shutdown): Ditto.
	(client_request_attach_tty): Ditto.

Tue Oct  2  9:57:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* Makefile.in: add threaded_queue.o to cygserver.exe.
	* cygserver.cc: Include threaded_queue.h
	(class server_request): Inherit from queue_request.
	(class server_process_param): Inherit from queue_process_param.
	(class server_request_queue): Inherit from threaded_queue.
	(request_loop): Adjust for new types.
	(server_request_queue::process_requests): Remove guts to
	threaded_queue::process_requests.
	(server_request::server_request): Adjust for new types.
	(worker_function): Delete.
	(server_request_queue::create_workers): Delete.
	(server_request_queue::cleanup): Delete.
	(server_request_queue::add): Move guts to threaded_queue::add.
	* threaded_queue.cc: New file.
	* threaded_queue.h: New file.

Mon Oct  1 12:38:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* cygserver.cc (client_request::serve): New function.
	* cygserver_process.cc: Inlude <pthread.h> for pthread_once.
	(process_cache::process_cache): Initialise a crtiical section for write access.
	(process_cache::process): Use the critical section. Also add missing entries to
	the cache.
	(do_process_init): New function to initalise class process static variables.
	(process::process): Ensure that the process access critical section is
	initialised.
	(process::handle): Close the handle of old process's when they have terminated
	and we are returning the handle for a process with the same pid.
	* cygserver_shm.cc: Run indent.
	Include cygserver_process.h to allow process cache functionality.
	(client_request_shm_get::serve): New parameter for process cache support.
	Use the process cache, not OpenProcess to get a handle to the originating process.
	Fix a handle leak with token_handle.
	* cygserver_shm.h (class client_request_shm_get): Update ::serve for process
	cache support.
	* cygserver_transport_pipes.cc: Redefine debug_printf to be conditional on DEBUG.
	* include/cygwin/cygserver.h: Do not implement client_request::serve in the
	header.
	* include/cygwin/cygserver_process.h (class process_cache): Add a write access
	critical section to prevent races when requests from a  multithreaded
	application arrive.

Sun Sep 30 23:41:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* Makefile.in: Add cygserver_process.o to cygserver.exe.
	* cygserver.cc: Include signal.h and cygwin_version.h.
	Define debug_printf as a macro.
	Define DEBUG to a value.
	(client_request_attach_tty::serve): Add beginning of process cache support.
	Change from #ifdef DEBUG to work with new DEBUG style.
	(client_request_get_version::serve): Add beginning of process cache support.
	(class server_request): New prototype for support of process cache.
	(class queue_process_param): New class to allow request loop threading.
	(class server_request_queue): Add beginning of process cache support.
	Allow request loop threading.
	(request_loop): Thread function for request loops.
	(server_request_queue::process_requests): Initiator for threaded request loops.
	(client_request_shutdown::serve): Add beginning of process cache support.
	(server_request::server_request): Ditto.
	(server_request::process): Use debug_printf. Add beginning of process cache
	support.
	(server_request_queue::cleanup): Kill off any request loop threads.
	(server_request_queue::add): Add beginning of process cache support.
	(handle_signal): Trigger a shutdown.
	(main): Print out some useful info at startup - version, date time.
	Add process cache support.
	Spawn a separate thread for the transport request loop, thus allowing concurrent
	support for multiple transports.
	* cygserver_client.cc (client_request_get_version::serve): Add process cache
	support.
	(client_request_attach_tty::serve): Add process cache support.
	(client_request_shutdown::serve): Add process cache support.
	* cygsserver_process.cc: New file with the process cache support.
	* cygserver_shm.cc: Redefine debug_printf to allow conditional output.
	* cygwin.din: Export shmdt().
	* shm.cc: Run indent.
	Update FIXME's.
	(shmdt): New function.
	* include/cygwin/cygserver.h (class client_request): Add process cache support.
	(class client_request_get_version): Ditto.
	(class client_request_shutdown): Ditto.
	(class client_request_attach_tty): Ditto.
	* include/cygwin/cygserver_process.h: New header for process cache support.

Sun Sep 30  8:52:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* include/cygwin/cygserver_transport.h: Add copyright header.
	* include/cygwin/cygserver_transport_pipes.h: Ditto.
	* include/cygwin/cygserver_transport_sockets.h: Ditto.

Sat Sep 29 20:40:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* Makefile.in: Add cygserver_transport_sockets.o to DLL_OFILES.
	Add cygserver_transport_sockets_outside.o to cygserver.exe.
	* cygserver.cc: Include new include files.
	* cygserver_client.cc: Ditto.
	* cygserver_shm.h: No need to include <sys/socket.h> now.
	* cygerver_transport.cc: Include new include files.
	(transport_layer_base::transport_layer_base): Strip back to a stub.
	(transport_layer_base::listen): Ditto.
	(transport_layer_base::accept): Ditto.
	(transport_layer_base::close): Ditto.
	(transport_layer_base::read): Ditto.
	(transport_layer_base::write): Ditto.
	(transport_layer_base::connect): Ditto.
	* cygserver_transport_pipes.cc: Include new header
	"cygwin/cygserver_transport_pipes.h".
	* cygserver_transport_sockets.cc: New file.
	* dcrt0.cc: No need to include <sys/socket.h> now.
	* fhandler_tty.cc: Ditto.
	* tty.cc: Ditto.
	* include/cygwin/cygserver_transport.h: Strip the base class to a stub.
	Remove the cygserver_transport_pipes class.
	* include/cygwin/cygserver_transport_pipes.h: New file.
	* include/cygwin/cygserver_transport_sockets.h: New file.

Tue Sep 25 16:22:00 2001  Robert Collins <rbtcollins@hotmail.com>

	* autoload.cc: Add dynamic load statement for 'ImpersonateNamedPipeClient'.
	* Makefile.in: Add new object files, and build instructions for cygserver.exe.
	* cygwin.din: Export ftok, shmat, shmctl and shmget.
	* dcrt0.cc: Additional includes for cygserver support.
	(dll_crt0_1): Initialise the cygserver client.
	* fhandler.h (fhandler_tty): New method cygserver_attach_tty.
	* fhandler_tty.cc: Additional includes for cygserver support.
	(fhandler_tty_slave::open): Attempt to use the cygserver when obtaining
	handles from the parent process. On failure or 9x use the current method.
	(fhandler_tty_slave::cygserver_attach_tty): New function.
	* fork.cc (fork_child): Fixup shm memory mapped areas.
	* pinfo.h: Declare fixup_shms_after_fork().
	* security.h: Declare alloc_sd().
	* tty.cc: Additonal includes to support cygserver.
	(tty::common_init): Don't allow others to open us if the cygserver is running.
	* winsup.h: Declare cygserver_running.
	* cygserver.cc: New file.
	* cygserver_client.cc: New file.
	* cygserver_shm.cc: New file.
	* cygserver_shm.h: New file.
	* cygserver_transport.cc: New file.
	* cygserver_transport_pipes.cc: New file.
	* ipc.cc: New file.
	* shm.cc: New file.
	* include/cygwin/cygserver.h: New file.
	* include/cygwin/cygserver_transport.h: New file.
	* include/sys/ipc.h: New file.
	* include/sys/shm.h: New file.

2002-02-28  Robert Collins  <rbtcollins@hotmail.com>

	* thread.cc (semaphore::TryWait): Set errno as required by posix 1003.1.
	(__sem_wait): Ditto.
	(__sem_trywait): Ditto.

1 files changed, 552 insertions, 0 deletions

diff --git a/winsup/cygserver/shm.cc b/winsup/cygserver/shm.cc
new file mode 100644
index 000000000..c29938bb9
--- /dev/null
+++ b/winsup/cygserver/shm.cc
@@ -0,0 +1,552 @@
+/* cygserver_shm.cc: Single unix specification IPC interface for Cygwin
+
+   Copyright 2001 Red Hat, Inc.
+
+   Originally written by Robert Collins <robert.collins@hotmail.com>
+
+   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. */
+
+
+#ifdef __OUTSIDE_CYGWIN__
+#undef __INSIDE_CYGWIN__
+#else
+#include "winsup.h"
+#endif
+
+#ifndef __INSIDE_CYGWIN__
+#define DEBUG 0
+#define system_printf printf
+#define debug_printf if (DEBUG) printf
+#define api_fatal printf
+#include <stdio.h>
+#include <windows.h>
+#endif
+
+#include <sys/stat.h>
+#include <errno.h>
+#include "cygerrno.h"
+#include <unistd.h>
+#include "security.h"
+//#include "fhandler.h"
+//#include "dtable.h"
+//#include "cygheap.h"
+#include <stdio.h>
+//#include "thread.h"
+#ifndef __INSIDE_CYGWIN__
+#define __INSIDE_CYGWIN__
+#include <sys/shm.h>
+#undef __INSIDE_CYGWIN__
+#else
+#include <sys/shm.h>
+#endif
+//#include "perprocess.h"
+#include <threaded_queue.h>
+#include <cygwin/cygserver_process.h>
+#include "cygserver_shm.h"
+
+// FIXME IS THIS CORRECT
+/* Implementation notes: We use two shared memory regions per key:
+ * One for the control structure, and one for the shared memory.
+ * While this has a higher overhead tham a single shared area,
+ * It allows more flexability. As the entire code is transparent to the user
+ * We can merge these in the future should it be needed.
+ * Also, IPC_PRIVATE keys create unique mappings each time. The shm_ids just
+ * keep monotonically incrementing - system wide.
+ */
+size_t
+getsystemallocgranularity ()
+{
+  SYSTEM_INFO sysinfo;
+  static size_t buffer_offset = 0;
+  if (buffer_offset)
+    return buffer_offset;
+  GetSystemInfo (&sysinfo);
+  buffer_offset = sysinfo.dwAllocationGranularity;
+  return buffer_offset;
+}
+
+
+client_request_shm::client_request_shm ():client_request (CYGSERVER_REQUEST_SHM_GET, sizeof (parameters))
+{
+  buffer = (char *) &parameters;
+}
+
+/* FIXME: If building on a 64-bit compiler, the address->int typecast will fail.
+ * Solution: manually calculate the next id value 
+ */
+
+#if 0
+extern "C" void *
+shmat (int shmid, const void *shmaddr, int parameters.in.shmflg)
+{
+  class shmid_ds *shm = (class shmid_ds *) shmid;	//FIXME: verifyable object test
+
+  if (shmaddr)
+    {
+      //FIXME: requested base address ?!
+      set_errno (EINVAL);
+      return (void *) -1;
+    }
+
+  void *rv = MapViewOfFile (shm->attachmap,
+
+
+			    (parameters.in.shmflg & SHM_RDONLY) ?
+			    FILE_MAP_READ : FILE_MAP_WRITE, 0,
+			    0, 0);
+
+  if (!rv)
+    {
+      //FIXME: translate GetLastError()
+      set_errno (EACCES);
+      return (void *) -1;
+    }
+
+/* FIXME: this needs to be globally protected to prevent a mismatch betwen
+ * attach count and attachees list
+ */
+
+  InterlockedIncrement (&shm->shm_nattch);
+  _shmattach *attachnode = new _shmattach;
+
+  attachnode->data = rv;
+  attachnode->next =
+    (_shmattach *) InterlockedExchangePointer ((LONG *) & shm->attachhead,
+					       (long int) attachnode);
+  return rv;
+}
+#endif
+
+/* FIXME: evaluate getuid() and getgid() against the requested mode. Then
+ * choose PAGE_READWRITE | PAGE_READONLY and FILE_MAP_WRITE  |  FILE_MAP_READ
+ * appropriately
+ */
+
+/* Test result from openbsd: shm ids are persistent cross process if a handle is left
+ * open. This could lead to resource starvation: we're not copying that behaviour 
+ * unless we have to. (It will involve acygwin1.dll gloal shared list :[ ).
+ */
+/* FIXME: shmid should be a verifyable object
+ */
+
+/* FIXME: on NT we should check everything against the SD. On 95 we just emulate.
+ */
+
+extern GENERIC_MAPPING access_mapping;
+
+extern int
+check_and_dup_handle (HANDLE from_process, HANDLE to_process,
+		      HANDLE from_process_token,
+		      DWORD access,
+		      HANDLE from_handle,
+		      HANDLE * to_handle_ptr, BOOL bInheritHandle);
+
+//FIXME: where should this live
+static shmnode *shm_head = NULL;
+/* must be long for InterlockedIncrement */
+static long new_id = 0;
+static long new_private_key = 0;
+
+void
+client_request_shm::serve (transport_layer_base * conn,
+			       process_cache * cache)
+{
+//  DWORD sd_size = 4096;
+//  char sd_buf[4096];
+  PSECURITY_DESCRIPTOR psd = (PSECURITY_DESCRIPTOR) parameters.in.sd_buf;
+//  /* create a sd for our open requests based on shmflag & 0x01ff */
+//  psd = alloc_sd (getuid (), getgid (), cygheap->user.logsrv (),
+//                parameters.in.shmflg & 0x01ff, psd, &sd_size);
+
+  HANDLE from_process_handle = NULL;
+  HANDLE token_handle = NULL;
+  DWORD rc;
+
+  from_process_handle = cache->process (parameters.in.pid)->handle ();
+  /* possible TODO: reduce the access on the handle before we use it */
+  /* Note that unless we do this, we don't need to call CloseHandle - it's kept open
+   * by the process cache until the process terminates. 
+   * We may need a refcount on the cache however... 
+   */
+  if (!from_process_handle)
+    {
+      debug_printf ("error opening process (%lu)\n", GetLastError ());
+      header.error_code = EACCES;
+      return;
+    }
+
+  conn->impersonate_client ();
+
+  rc = OpenThreadToken (GetCurrentThread (),
+			TOKEN_QUERY, TRUE, &token_handle);
+
+  conn->revert_to_self ();
+
+  if (!rc)
+    {
+      debug_printf ("error opening thread token (%lu)\n", GetLastError ());
+      header.error_code = EACCES;
+      CloseHandle (from_process_handle);
+      return;
+    }
+
+
+  /* we trust the clients request - we will be doing it as them, and
+   * the worst they can do is open their own permissions 
+   */
+
+
+  SECURITY_ATTRIBUTES sa;
+  sa.nLength = sizeof (sa);
+  sa.lpSecurityDescriptor = psd;
+  sa.bInheritHandle = TRUE;	/* the memory structures inherit ok */
+
+  char *shmname = NULL, *shmaname = NULL;
+  char stringbuf[29], stringbuf1[29];
+
+  /* TODO: make this code block a function! */
+  if (parameters.in.type == SHM_REATTACH)
+    {
+      /* just find and fill out the existing shm_id */
+      shmnode *tempnode = shm_head;
+      while (tempnode)
+	{
+	  if (tempnode->shm_id == parameters.in.shm_id)
+	    {
+	      parameters.out.shm_id = tempnode->shm_id;
+	      parameters.out.key = tempnode->key;
+	      if (check_and_dup_handle
+		  (GetCurrentProcess (), from_process_handle, token_handle,
+		   DUPLICATE_SAME_ACCESS, tempnode->filemap,
+		   &parameters.out.filemap, TRUE) != 0)
+		{
+		  debug_printf ("error duplicating filemap handle (%lu)\n",
+				GetLastError ());
+		  header.error_code = EACCES;
+		}
+	      if (check_and_dup_handle
+		  (GetCurrentProcess (), from_process_handle, token_handle,
+		   DUPLICATE_SAME_ACCESS, tempnode->attachmap,
+		   &parameters.out.attachmap, TRUE) != 0)
+		{
+		  debug_printf ("error duplicating attachmap handle (%lu)\n",
+				GetLastError ());
+		  header.error_code = EACCES;
+		}
+	      CloseHandle (token_handle);
+	      return;
+	    }
+	  tempnode = tempnode->next;
+	}
+      header.error_code = EINVAL;
+      CloseHandle (token_handle);
+      return;
+    }
+
+  /* someone attached */
+  /* someone can send shm_id's they don't have and currently we will increment those
+   * attach counts. If someone wants to fix that, please go ahead.
+   * The problem is that shm_get has nothing to do with the ability to attach. Attach
+   * requires a permission check, which we get the OS to do in MapViewOfFile.
+   */
+  if (parameters.in.type == SHM_ATTACH)
+    {
+      shmnode *tempnode = shm_head;
+      while (tempnode)
+        {
+          if (tempnode->shm_id == parameters.in.shm_id)
+            {
+	      InterlockedIncrement (&tempnode->shmds->shm_nattch);
+	      header.error_code = 0;
+              CloseHandle (token_handle);
+              return;
+            }
+          tempnode = tempnode->next;
+        }
+      header.error_code = EINVAL;
+      CloseHandle (token_handle);
+      return;
+    }
+
+  /* it's a original request from the users */
+
+  /* FIXME: enter the checking for existing keys mutex. This mutex _must_ be system wide
+   * to prevent races on shmget.
+   */
+
+  if (parameters.in.key == IPC_PRIVATE)
+    {
+      /* create the mapping name (CYGWINSHMKPRIVATE_0x01234567 */
+      /* The K refers to Key, the actual mapped area has D */
+      long private_key = (int) InterlockedIncrement (&new_private_key);
+      snprintf (stringbuf, 29, "CYGWINSHMKPRIVATE_0x%0x", private_key);
+      shmname = stringbuf;
+      snprintf (stringbuf1, 29, "CYGWINSHMDPRIVATE_0x%0x", private_key);
+      shmaname = stringbuf1;
+    }
+  else
+    {
+      /* create the mapping name (CYGWINSHMK0x0123456789abcdef */
+      /* The K refers to Key, the actual mapped area has D */
+
+      snprintf (stringbuf, 29, "CYGWINSHMK0x%0qx", parameters.in.key);
+      shmname = stringbuf;
+      snprintf (stringbuf1, 29, "CYGWINSHMD0x%0qx", parameters.in.key);
+      shmaname = stringbuf1;
+      debug_printf ("system id strings are \n%s\n%s\n", shmname, shmaname);
+      debug_printf ("key input value is 0x%0qx\n", parameters.in.key);
+    }
+
+  /* attempt to open the key */
+
+  /* get an existing key */
+  /* On unix the same shmid identifier is returned on multiple calls to shm_get 
+   * with the same key and size. Different modes is a ?.
+   */
+
+
+
+  /* walk the list of known keys and return the id if found. remember, we are
+   * authoritative...
+   */
+
+  shmnode *tempnode = shm_head;
+  while (tempnode)
+    {
+      if (tempnode->key == parameters.in.key
+	  && parameters.in.key != IPC_PRIVATE)
+	{
+	  // FIXME: free the mutex
+	  if (parameters.in.size
+	      && tempnode->shmds->shm_segsz < parameters.in.size)
+	    {
+	      header.error_code = EINVAL;
+	      CloseHandle (token_handle);
+	      return;
+	    }
+	  /* FIXME: can the same process call this twice without error ? test 
+	   * on unix
+	   */
+	  if ((parameters.in.shmflg & IPC_CREAT)
+	      && (parameters.in.shmflg & IPC_EXCL))
+	    {
+	      header.error_code = EEXIST;
+	      debug_printf
+		("attempt to exclusively create already created shm_area with key 0x%0qx\n",
+		 parameters.in.key);
+	      // FIXME: free the mutex
+	      CloseHandle (token_handle);
+	      return;
+	    }
+	  // FIXME: do we need to other tests of the requested mode with the 
+	  // tempnode->shm_id mode ? testcase on unix needed.
+	  // FIXME how do we do the security test? or
+	  // do we wait for shmat to bother with that?
+	  /* One possibly solution: impersonate the client, and then test we can
+	   * reopen the area. In fact we'll probably have to do that to get 
+	   * handles back to them, alternatively just tell them the id, and then
+	   * let them attempt the open.
+	   */
+	  parameters.out.shm_id = tempnode->shm_id;
+	  if (check_and_dup_handle (GetCurrentProcess (), from_process_handle,
+				    token_handle,
+				    DUPLICATE_SAME_ACCESS,
+				    tempnode->filemap,
+				    &parameters.out.filemap, TRUE) != 0)
+	    {
+	      printf ("error duplicating filemap handle (%lu)\n",
+		      GetLastError ());
+	      header.error_code = EACCES;
+/*mutex*/
+	      CloseHandle (token_handle);
+	      return;
+	    }
+	  if (check_and_dup_handle (GetCurrentProcess (), from_process_handle,
+				    token_handle,
+				    DUPLICATE_SAME_ACCESS,
+				    tempnode->attachmap,
+				    &parameters.out.attachmap, TRUE) != 0)
+	    {
+	      printf ("error duplicating attachmap handle (%lu)\n",
+		      GetLastError ());
+	      header.error_code = EACCES;
+/*mutex*/
+	      CloseHandle (token_handle);
+	      return;
+	    }
+
+	  CloseHandle (token_handle);
+	  return;
+	}
+      tempnode = tempnode->next;
+    }
+  /* couldn't find a currently open shm area. */
+
+  /* create one */
+  /* do this as the client */
+  conn->impersonate_client ();
+  /* This may need sh_none... it's only a control structure */
+  HANDLE filemap = CreateFileMapping (INVALID_HANDLE_VALUE,	// system pagefile.
+				      &sa,
+				      PAGE_READWRITE,	// protection  
+				      0x00000000,
+				      getsystemallocgranularity (),
+				      shmname	// object name
+    );
+  int lasterr = GetLastError ();
+  conn->revert_to_self ();
+
+  if (filemap == NULL)
+    {
+      /* We failed to open the filemapping ? */
+      system_printf ("failed to open file mapping: %lu\n", GetLastError ());
+      // free the mutex
+      // we can assume that it exists, and that it was an access problem.
+      header.error_code = EACCES;
+      CloseHandle (token_handle);
+      return;
+    }
+
+  /* successfully opened the control region mapping */
+  /* did we create it ? */
+  int oldmapping = lasterr == ERROR_ALREADY_EXISTS;
+  if (oldmapping)
+    {
+      /* should never happen - we are the global daemon! */
+#if 0
+      if ((parameters.in.shmflg & IPC_CREAT)
+	  && (parameters.in.shmflg & IPC_EXCL))
+#endif
+	{
+	  /* FIXME free mutex */
+	  CloseHandle (filemap);
+	  header.error_code = EEXIST;
+	  CloseHandle (token_handle);
+	  return;
+	}
+    }
+
+  /* we created a new mapping */
+  if (parameters.in.key != IPC_PRIVATE &&
+      (parameters.in.shmflg & IPC_CREAT) == 0)
+    {
+      CloseHandle (filemap);
+      /* FIXME free mutex */
+      header.error_code = ENOENT;
+      CloseHandle (token_handle);
+      return;
+    }
+
+  conn->impersonate_client ();
+  void *mapptr = MapViewOfFile (filemap, FILE_MAP_WRITE, 0, 0, 0);
+  conn->revert_to_self ();
+
+  if (!mapptr)
+    {
+      CloseHandle (filemap);
+      //FIXME: close filemap and free the mutex
+      /* we couldn't access the mapped area with the requested permissions */
+      header.error_code = EACCES;
+      CloseHandle (token_handle);
+      return;
+    }
+
+  conn->impersonate_client ();
+  /* Now get the user data */
+  HANDLE attachmap = CreateFileMapping (INVALID_HANDLE_VALUE,	// system pagefile
+					&sa,
+					PAGE_READWRITE,	// protection (FIXME)
+					0x00000000,
+					parameters.in.size +
+					parameters.in.size %
+					getsystemallocgranularity (),
+					shmaname	// object name
+    );
+  conn->revert_to_self ();
+
+  if (attachmap == NULL)
+    {
+      system_printf ("failed to get shm attachmap\n");
+      header.error_code = ENOMEM;
+      UnmapViewOfFile (mapptr);
+      CloseHandle (filemap);
+      /* FIXME exit the mutex */
+      CloseHandle (token_handle);
+      return;
+    }
+
+  shmid_ds *shmtemp = new shmid_ds;
+  if (!shmtemp)
+    {
+      system_printf ("failed to malloc shm node\n");
+      header.error_code = ENOMEM;
+      UnmapViewOfFile (mapptr);
+      CloseHandle (filemap);
+      CloseHandle (attachmap);
+      /* FIXME exit mutex */
+      CloseHandle (token_handle);
+      return;
+    }
+
+  /* fill out the node data */
+  shmtemp->shm_perm.cuid = getuid ();
+  shmtemp->shm_perm.uid = shmtemp->shm_perm.cuid;
+  shmtemp->shm_perm.cgid = getgid ();
+  shmtemp->shm_perm.gid = shmtemp->shm_perm.cgid;
+  shmtemp->shm_perm.mode = parameters.in.shmflg & 0x01ff;
+  shmtemp->shm_lpid = 0;
+  shmtemp->shm_nattch = 0;
+  shmtemp->shm_atime = 0;
+  shmtemp->shm_dtime = 0;
+  shmtemp->shm_ctime = time (NULL);
+  shmtemp->shm_segsz = parameters.in.size;
+  *(shmid_ds *) mapptr = *shmtemp;
+  shmtemp->mapptr = mapptr;
+
+  /* no need for InterlockedExchange here, we're serialised by the global mutex */
+  tempnode = new shmnode;
+  tempnode->shmds = shmtemp;
+  tempnode->shm_id = (int) InterlockedIncrement (&new_id);
+  tempnode->key = parameters.in.key;
+  tempnode->filemap = filemap;
+  tempnode->attachmap = attachmap;
+  tempnode->next = shm_head;
+  shm_head = tempnode;
+
+  /* we now have the area in the daemon list, opened. 
+
+     FIXME: leave the system wide shm mutex */
+
+  parameters.out.shm_id = tempnode->shm_id;
+  if (check_and_dup_handle (GetCurrentProcess (), from_process_handle,
+			    token_handle,
+			    DUPLICATE_SAME_ACCESS,
+			    tempnode->filemap, &parameters.out.filemap,
+			    TRUE) != 0)
+    {
+      printf ("error duplicating filemap handle (%lu)\n", GetLastError ());
+      header.error_code = EACCES;
+      CloseHandle (token_handle);
+/* mutex et al */
+      return;
+    }
+  if (check_and_dup_handle (GetCurrentProcess (), from_process_handle,
+			    token_handle,
+			    DUPLICATE_SAME_ACCESS,
+			    tempnode->attachmap, &parameters.out.attachmap,
+			    TRUE) != 0)
+    {
+      printf ("error duplicating attachmap handle (%lu)\n", GetLastError ());
+      header.error_code = EACCES;
+      CloseHandle (from_process_handle);
+      CloseHandle (token_handle);
+/* more cleanup... yay! */
+      return;
+    }
+  CloseHandle (token_handle);
+  return;
+}