* shared_info.h (user_info): Add dll_crt0_1 as a friend.

(user_info::version): Make LONG to accommodate spinlock use.
(user_info::create): New static function renamed from user_info_create.
(user_info::initialize): New private function renamed from
user_info_initialize.
(SHARED_VERSION): Delete.
(SHARED_VERSION_MAGIC): Ditto.
(USER_VERSION_MAGIC): Ditto.
(SHARED_INFO_CB): Ditto.
(USER_VERSION): Ditto.
(USER_VERSION_MAGIC): Ditto.
(CURR_SHARED_MAGIC): Update.
(CURR_USER_MAGIC): Ditto.
(shared_info::version): Make LONG to accommodate spinlock use.
(shared_info::create): New static function mirroring user_info::create.
(dll_crt0_1): Accommodate change to user_info::initialize.
* spinlock.h (spinlock::setto): New variable member.
(spinlock::done): New function.
(spinlock::spinlock): Generalize to allow arbitrary values and timeouts.  Call
done() when lock is not needed.
* ntdll.h: Make multiple-inclusion safe.
(NtQuerySystemTime): Declare.
* shared.cc (installation_root_inited): Rename from shared_mem_inited.
(init_installation_root): Make inline.  Use a spinlock to ensure that this is
initialized only once per session.
(user_info::initialize): Rename from user_shared_initialize.  Protect with
spinlock on sversion and remove other spinlock-like things.  Remove reference
to user_shared since it is now implicit.  Refer to spinlock version of
multiple_cygwin_problem to ensure that any spinlock is released.
(user_info::create): Rename from user_shared_create.  Accommodate change from
user_shared_initialize to user_info::initialize.
(shared_info::create): New inline function.
(shared_info::initialize): Protect with spinlock on sversion.  Move heap_init
back under specific control of shared_info spinlock.  Remove reference to
SHARED_INFO_CB and just use sizeof(*this).
(memory_init): Move all locking into respective functions where it is needed.
Accommodate name changes.  Remove call to heap_init().
* syscalls.cc (seteuid32): Accommodate name change to user_info::create().
* mount.cc (mount_info::create_root_entry): Report on errors from add_item
since they should be nonexistent.
(mount_info::init): Don't initialize nmounts.  It should already be zero.  Give
more verbose error when root_idx < 0.  Implicitly use this pointer rather than
explicitly referencing mount_table->.
(mount_info::add_item): Minor whitespace fix.

8 files changed, 218 insertions, 128 deletions

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 24ad6aa8a..141bf302b 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,5 +1,55 @@
 2010-03-15  Christopher Faylor  <me+cygwin@cgf.cx>
 
+	* shared_info.h (user_info): Add dll_crt0_1 as a friend.
+	(user_info::version): Make LONG to accommodate spinlock use.
+	(user_info::create): New static function renamed from user_info_create.
+	(user_info::initialize): New private function renamed from
+	user_info_initialize.
+	(SHARED_VERSION): Delete.
+	(SHARED_VERSION_MAGIC): Ditto.
+	(USER_VERSION_MAGIC): Ditto.
+	(SHARED_INFO_CB): Ditto.
+	(USER_VERSION): Ditto.
+	(USER_VERSION_MAGIC): Ditto.
+	(CURR_SHARED_MAGIC): Update.
+	(CURR_USER_MAGIC): Ditto.
+	(shared_info::version): Make LONG to accommodate spinlock use.
+	(shared_info::create): New static function mirroring user_info::create.
+	(dll_crt0_1): Accommodate change to user_info::initialize.
+	* spinlock.h (spinlock::setto): New variable member.
+	(spinlock::done): New function.
+	(spinlock::spinlock): Generalize to allow arbitrary values and
+	timeouts.  Call done() when lock is not needed.
+	* ntdll.h: Make multiple-inclusion safe.
+	(NtQuerySystemTime): Declare.
+	* shared.cc (installation_root_inited): Rename from shared_mem_inited.
+	(init_installation_root): Make inline.  Use a spinlock to ensure that
+	this is initialized only once per session.
+	(user_info::initialize): Rename from user_shared_initialize.  Protect
+	with spinlock on sversion and remove other spinlock-like things.
+	Remove reference to user_shared since it is now implicit.  Refer to
+	spinlock version of multiple_cygwin_problem to ensure that any spinlock
+	is released.
+	(user_info::create): Rename from user_shared_create.  Accommodate
+	change from user_shared_initialize to user_info::initialize.
+	(shared_info::create): New inline function.
+	(shared_info::initialize): Protect with spinlock on sversion.  Move
+	heap_init back under specific control of shared_info spinlock.  Remove
+	reference to SHARED_INFO_CB and just use sizeof(*this).
+	(memory_init): Move all locking into respective functions where it is
+	needed.  Accommodate name changes.  Remove call to heap_init().
+	* syscalls.cc (seteuid32): Accommodate name change to
+	user_info::create().
+
+	* mount.cc (mount_info::create_root_entry): Report on errors from
+	add_item since they should be nonexistent.
+	(mount_info::init): Don't initialize nmounts.  It should already be
+	zero.  Give more verbose error when root_idx < 0.  Implicitly use this
+	pointer rather than explicitly referencing mount_table->.
+	(mount_info::add_item): Minor whitespace fix.
+
+2010-03-15  Christopher Faylor  <me+cygwin@cgf.cx>
+
 	* sigproc.cc (no_signals_available): Get sense of the test right for
 	previous botched change.
 
diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index 5cee9f886..6a1a341aa 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -778,7 +778,7 @@ dll_crt0_1 (void *)
      have overridden malloc.  We only know about that at this stage,
      unfortunately. */
   malloc_init ();
-  user_shared_initialize ();
+  user_shared->initialize ();
 
 #ifdef CGF
   int i = 0;
diff --git a/winsup/cygwin/mount.cc b/winsup/cygwin/mount.cc
index e8d181125..d8dbb7662 100644
--- a/winsup/cygwin/mount.cc
+++ b/winsup/cygwin/mount.cc
@@ -338,8 +338,11 @@ mount_info::create_root_entry (const PWCHAR root)
     The entry is immutable, unless the "override" option is given in /etc/fstab. */
   char native_root[PATH_MAX];
   sys_wcstombs (native_root, PATH_MAX, root);
-  mount_table->add_item (native_root, "/",
-			 MOUNT_SYSTEM | MOUNT_BINARY | MOUNT_IMMUTABLE | MOUNT_AUTOMATIC);
+  assert (*native_root != '\0');
+  if (add_item (native_root, "/",
+		MOUNT_SYSTEM | MOUNT_BINARY | MOUNT_IMMUTABLE | MOUNT_AUTOMATIC)
+      < 0)
+    api_fatal ("add_item (\"%W\", \"/\", ...) failed, errno %d", native_root, errno);
   /* Create a default cygdrive entry.  Note that this is a user entry.
      This allows to override it with mount, unless the sysadmin created
      a cygdrive entry in /etc/fstab. */
@@ -353,7 +356,6 @@ mount_info::create_root_entry (const PWCHAR root)
 void
 mount_info::init ()
 {
-  nmounts = 0;
   PWCHAR pathend;
   WCHAR path[PATH_MAX];
 
@@ -367,19 +369,20 @@ mount_info::init ()
   if (!got_usr_bin || !got_usr_lib)
     {
       char native[PATH_MAX];
-      assert (root_idx != -1);
+      if (root_idx < 0)
+	api_fatal ("root_idx %d, user_shared magic %p, nmounts %d", root_idx, user_shared->version, nmounts);
       char *p = stpcpy (native, mount[root_idx].native_path);
       if (!got_usr_bin)
       {
 	stpcpy (p, "\\bin");
-	mount_table->add_item (native, "/usr/bin",
-			       MOUNT_SYSTEM | MOUNT_BINARY | MOUNT_AUTOMATIC);
+	add_item (native, "/usr/bin",
+		  MOUNT_SYSTEM | MOUNT_BINARY | MOUNT_AUTOMATIC);
       }
       if (!got_usr_lib)
       {
 	stpcpy (p, "\\lib");
-	mount_table->add_item (native, "/usr/lib",
-			       MOUNT_SYSTEM | MOUNT_BINARY | MOUNT_AUTOMATIC);
+	add_item (native, "/usr/lib",
+		  MOUNT_SYSTEM | MOUNT_BINARY | MOUNT_AUTOMATIC);
       }
     }
 }
@@ -1285,7 +1288,7 @@ mount_info::add_item (const char *native, const char *posix,
 
   if (nativeerr || posixerr)
     {
-      set_errno (nativeerr?:posixerr);
+      set_errno (nativeerr ?: posixerr);
       return -1;
     }
 
diff --git a/winsup/cygwin/ntdll.h b/winsup/cygwin/ntdll.h
index 465d52782..7ac15cb18 100644
--- a/winsup/cygwin/ntdll.h
+++ b/winsup/cygwin/ntdll.h
@@ -9,6 +9,8 @@
    Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
    details. */
 
+#ifndef _NTDLL_H
+#define _NTDLL_H 1
 #define STATUS_NOT_ALL_ASSIGNED       ((NTSTATUS) 0x00000106)
 #define STATUS_OBJECT_NAME_EXISTS     ((NTSTATUS) 0x40000000)
 #define STATUS_BUFFER_OVERFLOW        ((NTSTATUS) 0x80000005)
@@ -937,6 +939,9 @@ extern "C"
 				ULONG, ULONG *);
   NTSTATUS NTAPI NtQuerySystemInformation (SYSTEM_INFORMATION_CLASS,
 					   PVOID, ULONG, PULONG);
+
+  NTSTATUS WINAPI NtQuerySystemTime (PLARGE_INTEGER);
+
   NTSTATUS NTAPI NtQuerySecurityObject (HANDLE, SECURITY_INFORMATION,
 					PSECURITY_DESCRIPTOR, ULONG, PULONG);
   NTSTATUS NTAPI NtQueryVirtualMemory (HANDLE, PVOID, MEMORY_INFORMATION_CLASS,
@@ -1094,3 +1099,4 @@ extern "C"
     return NtSetInformationFile(h, &io, &fbi, sizeof fbi, FileBasicInformation);
   }
 }
+#endif /*_NTDLL_H*/
diff --git a/winsup/cygwin/shared.cc b/winsup/cygwin/shared.cc
index 6e166f3fa..4ef8807aa 100644
--- a/winsup/cygwin/shared.cc
+++ b/winsup/cygwin/shared.cc
@@ -24,7 +24,6 @@ details. */
 #include "cygwin_version.h"
 #include "pwdgrp.h"
 #include "spinlock.h"
-#include "ntdll.h"
 #include <alloca.h>
 #include <wchar.h>
 #include <wingdi.h>
@@ -38,7 +37,9 @@ HANDLE NO_COPY cygwin_user_h;
 WCHAR installation_root[PATH_MAX] __attribute__((section (".cygwin_dll_common"), shared));
 UNICODE_STRING installation_key __attribute__((section (".cygwin_dll_common"), shared));
 WCHAR installation_key_buf[18] __attribute__((section (".cygwin_dll_common"), shared));
-static LONG shared_mem_inited __attribute__((section (".cygwin_dll_common"), shared));
+static LONG installation_root_inited __attribute__((section (".cygwin_dll_common"), shared));
+
+#define SPIN_WAIT 10000
 
 /* Use absolute path of cygwin1.dll to derive the Win32 dir which
    is our installation_root.  Note that we can't handle Cygwin installation
@@ -63,58 +64,61 @@ static LONG shared_mem_inited __attribute__((section (".cygwin_dll_common"), sha
    multiple Cygwin DLLs, which we're just not aware of right now.  Cygcheck
    can be used to change the value in an existing Cygwin DLL binary. */
 
-void
+void inline
 init_installation_root ()
 {
-  if (!GetModuleFileNameW (cygwin_hmodule, installation_root, PATH_MAX))
-    api_fatal ("Can't initialize Cygwin installation root dir.\n"
-	       "GetModuleFileNameW(%p, %p, %u), %E",
-	       cygwin_hmodule, installation_root, PATH_MAX);
-  PWCHAR p = installation_root;
-  if (wcsncmp (p, L"\\\\?\\", 4))	/* No long path prefix. */
+  if (!spinlock (installation_root_inited))
     {
-      if (!wcsncasecmp (p, L"\\\\", 2))	/* UNC */
+      if (!GetModuleFileNameW (cygwin_hmodule, installation_root, PATH_MAX))
+	api_fatal ("Can't initialize Cygwin installation root dir.\n"
+		   "GetModuleFileNameW(%p, %p, %u), %E",
+		   cygwin_hmodule, installation_root, PATH_MAX);
+      PWCHAR p = installation_root;
+      if (wcsncmp (p, L"\\\\?\\", 4))	/* No long path prefix. */
 	{
-	  p = wcpcpy (p, L"\\??\\UN");
-	  GetModuleFileNameW (cygwin_hmodule, p, PATH_MAX - 6);
-	  *p = L'C';
+	  if (!wcsncasecmp (p, L"\\\\", 2))	/* UNC */
+	    {
+	      p = wcpcpy (p, L"\\??\\UN");
+	      GetModuleFileNameW (cygwin_hmodule, p, PATH_MAX - 6);
+	      *p = L'C';
+	    }
+	  else
+	    {
+	      p = wcpcpy (p, L"\\??\\");
+	      GetModuleFileNameW (cygwin_hmodule, p, PATH_MAX - 4);
+	    }
 	}
-      else
-	{
-	  p = wcpcpy (p, L"\\??\\");
-	  GetModuleFileNameW (cygwin_hmodule, p, PATH_MAX - 4);
-	}
-    }
-  installation_root[1] = L'?';
+      installation_root[1] = L'?';
 
-  RtlInitEmptyUnicodeString (&installation_key, installation_key_buf,
-			     sizeof installation_key_buf);
-  RtlInt64ToHexUnicodeString (hash_path_name (0, installation_root),
-			      &installation_key, FALSE);
+      RtlInitEmptyUnicodeString (&installation_key, installation_key_buf,
+				 sizeof installation_key_buf);
+      RtlInt64ToHexUnicodeString (hash_path_name (0, installation_root),
+				  &installation_key, FALSE);
 
-  PWCHAR w = wcsrchr (installation_root, L'\\');
-  if (w)
-    {
+      PWCHAR w = wcsrchr (installation_root, L'\\');
+      if (w)
+	{
+	  *w = L'\0';
+	  w = wcsrchr (installation_root, L'\\');
+	}
+      if (!w)
+	api_fatal ("Can't initialize Cygwin installation root dir.\n"
+		   "Invalid DLL path");
       *w = L'\0';
-      w = wcsrchr (installation_root, L'\\');
-    }
-  if (!w)
-    api_fatal ("Can't initialize Cygwin installation root dir.\n"
-	       "Invalid DLL path");
-  *w = L'\0';
 
-  for (int i = 1; i >= 0; --i)
-    {
-      reg_key r (i, KEY_WRITE, CYGWIN_INFO_INSTALLATIONS_NAME, NULL);
-      if (r.set_string (installation_key_buf, installation_root)
-	  == ERROR_SUCCESS)
-      	break;
-    }
+      for (int i = 1; i >= 0; --i)
+	{
+	  reg_key r (i, KEY_WRITE, CYGWIN_INFO_INSTALLATIONS_NAME, NULL);
+	  if (r.set_string (installation_key_buf, installation_root)
+	      == ERROR_SUCCESS)
+	    break;
+	}
 
-  if (cygwin_props.disable_key)
-    {
-      installation_key.Length = 0;
-      installation_key.Buffer[0] = L'\0';
+      if (cygwin_props.disable_key)
+	{
+	  installation_key.Length = 0;
+	  installation_key.Buffer[0] = L'\0';
+	}
     }
 }
 
@@ -301,35 +305,32 @@ open_shared (const WCHAR *name, int n, HANDLE& shared_h, DWORD size,
 
 /* Second half of user shared initialization: Initialize content. */
 void
-user_shared_initialize ()
+user_info::initialize ()
 {
-  DWORD sversion = (DWORD) InterlockedExchange ((LONG *) &user_shared->version, USER_VERSION_MAGIC);
   /* Wait for initialization of the Cygwin per-user shared, if necessary */
+  spinlock sversion (version, CURR_USER_MAGIC);
   if (!sversion)
     {
+      cb =  sizeof (*user_shared);
       cygpsid sid (cygheap->user.sid ());
       struct passwd *pw = internal_getpwsid (sid);
       /* Correct the user name with what's defined in /etc/passwd before
 	 loading the user fstab file. */
       if (pw)
 	cygheap->user.set_name (pw->pw_name);
-      user_shared->mountinfo.init ();	/* Initialize the mount table.  */
-      user_shared->cb =  sizeof (*user_shared);
-    }
-  else
-    {
-      while (!user_shared->cb)
-	yield ();	// Should be hit only very very rarely
-      if (user_shared->version != sversion)
-	multiple_cygwin_problem ("user shared memory version", user_shared->version, sversion);
-      else if (user_shared->cb != sizeof (*user_shared))
-	multiple_cygwin_problem ("user shared memory size", user_shared->cb, sizeof (*user_shared));
+      mountinfo.init ();	/* Initialize the mount table.  */
     }
+  else if (sversion != CURR_USER_MAGIC)
+    sversion.multiple_cygwin_problem ("user shared memory version", version,
+				      sversion);
+  else if (user_shared->cb != sizeof (*user_shared))
+    sversion.multiple_cygwin_problem ("user shared memory size", cb,
+				      sizeof (*user_shared));
 }
 
 /* First half of user shared initialization: Create shared mem region. */
 void
-user_shared_create (bool reinit)
+user_info::create (bool reinit)
 {
   WCHAR name[UNLEN + 1] = L""; /* Large enough for SID */
 
@@ -352,7 +353,7 @@ user_shared_create (bool reinit)
   ProtectHandleINH (cygwin_user_h);
   debug_printf ("user shared version %x", user_shared->version);
   if (reinit)
-    user_shared_initialize ();
+    user_shared->initialize ();
 }
 
 void __stdcall
@@ -383,10 +384,21 @@ shared_info::init_obcaseinsensitive ()
   debug_printf ("obcaseinsensitive set to %d", obcaseinsensitive);
 }
 
+void inline
+shared_info::create ()
+{
+  cygwin_shared = (shared_info *) open_shared (L"shared",
+					       CYGWIN_VERSION_SHARED_DATA,
+					       cygwin_shared_h,
+					       sizeof (*cygwin_shared),
+					       SH_CYGWIN_SHARED);
+  cygwin_shared->initialize ();
+}
+
 void
 shared_info::initialize ()
 {
-  DWORD sversion = (DWORD) InterlockedExchange ((LONG *) &version, SHARED_VERSION_MAGIC);
+  spinlock sversion (version, CURR_SHARED_MAGIC);
   if (!sversion)
     {
       cb = sizeof (*this);
@@ -394,16 +406,19 @@ shared_info::initialize ()
       init_obcaseinsensitive ();	/* Initialize obcaseinsensitive */
       tty.init ();			/* Initialize tty table  */
       mt.initialize ();			/* Initialize shared tape information */
+      /* Defer debug output printing the installation root and installation key
+	 up to this point.  Debug output except for system_printf requires
+	 the global shared memory to exist. */
+      debug_printf ("Installation root: <%W> key: <%S>",
+		    installation_root, &installation_key);
     }
-  else if (sversion != SHARED_VERSION_MAGIC)
-    {
-      InterlockedExchange ((LONG *) &version, sversion);
-      multiple_cygwin_problem ("system shared memory version", sversion, SHARED_VERSION_MAGIC);
-    }
-
-  if (cb != SHARED_INFO_CB)
+  else if (sversion != (LONG) CURR_SHARED_MAGIC)
+    sversion.multiple_cygwin_problem ("system shared memory version",
+				      sversion, CURR_SHARED_MAGIC);
+  else if (cb != sizeof (*this))
     system_printf ("size of shared memory region changed from %u to %u",
-		   SHARED_INFO_CB, cb);
+		   sizeof (*this), cb);
+  heap_init ();
 }
 
 void
@@ -418,30 +433,9 @@ memory_init (bool init_cygheap)
       cygheap->user.init ();
     }
 
-  /* Initialize general shared memory under spinlock control */
-  {
-    spinlock smi (shared_mem_inited, 10000);
-    if (!smi)
-      init_installation_root ();	/* Initialize installation root dir */
-
-    cygwin_shared = (shared_info *) open_shared (L"shared",
-						 CYGWIN_VERSION_SHARED_DATA,
-						 cygwin_shared_h,
-						 sizeof (*cygwin_shared),
-						 SH_CYGWIN_SHARED);
-    heap_init ();
-
-    if (!smi)
-      {
-	cygwin_shared->initialize ();
-	/* Defer debug output printing the installation root and installation key
-	   up to this point.  Debug output except for system_printf requires
-	   the global shared memory to exist. */
-	debug_printf ("Installation root: <%W> key: <%S>",
-		      installation_root, &installation_key);
-      }
-  }
-  user_shared_create (false);
+  init_installation_root ();	/* Initialize installation root dir */
+  shared_info::create ();	/* Initialize global shared memory */
+  user_info::create (false);	/* Initialize per-user shared memory */
 }
 
 unsigned
diff --git a/winsup/cygwin/shared_info.h b/winsup/cygwin/shared_info.h
index 52e6ce3df..f25ea15e2 100644
--- a/winsup/cygwin/shared_info.h
+++ b/winsup/cygwin/shared_info.h
@@ -16,33 +16,30 @@ details. */
 
 class user_info
 {
+  void initialize ();
 public:
-  DWORD version;
+  LONG version;
   DWORD cb;
   bool warned_msdos;
   mount_info mountinfo;
+  friend void dll_crt0_1 (void *);
+  static void create (bool);
 };
 /******** Shared Info ********/
 /* Data accessible to all tasks */
 
-#define SHARED_VERSION (unsigned)(cygwin_version.api_major << 8 | \
-				  cygwin_version.api_minor)
-#define SHARED_VERSION_MAGIC CYGWIN_VERSION_MAGIC (SHARED_MAGIC, SHARED_VERSION)
-
-#define SHARED_INFO_CB 31136
 
-#define CURR_SHARED_MAGIC 0x18da899eU
+#define CURR_SHARED_MAGIC 0xcebb78fcU
 
-#define USER_VERSION	1	// increment when mount table changes and
-#define USER_VERSION_MAGIC CYGWIN_VERSION_MAGIC (USER_MAGIC, USER_VERSION)
-#define CURR_USER_MAGIC 0xb2232e71U
+#define USER_VERSION   1
+#define CURR_USER_MAGIC 0x6112afb3U
 
 /* NOTE: Do not make gratuitous changes to the names or organization of the
    below class.  The layout is checksummed to determine compatibility between
    different cygwin versions. */
 class shared_info
 {
-  DWORD version;
+  LONG version;
   DWORD cb;
  public:
   unsigned heap_chunk;
@@ -58,6 +55,7 @@ class shared_info
   void init_obcaseinsensitive ();
   unsigned heap_chunk_size ();
   unsigned heap_slop_size ();
+  static void create ();
 };
 
 extern shared_info *cygwin_shared;
@@ -104,7 +102,6 @@ void *__stdcall open_shared (const WCHAR *, int, HANDLE&, DWORD,
 			     shared_locations *, PSECURITY_ATTRIBUTES = &sec_all,
 			     DWORD = FILE_MAP_READ | FILE_MAP_WRITE);
 extern void user_shared_create (bool reinit);
-extern void user_shared_initialize ();
 extern void init_installation_root ();
 extern WCHAR installation_root[PATH_MAX];
 extern UNICODE_STRING installation_key;
diff --git a/winsup/cygwin/spinlock.h b/winsup/cygwin/spinlock.h
index abf723acc..b55817245 100644
--- a/winsup/cygwin/spinlock.h
+++ b/winsup/cygwin/spinlock.h
@@ -11,30 +11,70 @@ details. */
 #ifndef _SPINLOCK_H
 #define _SPINLOCK_H
 
-#include "hires.h"
+#include "ntdll.h"
+
+#define SPINLOCK_WAIT (15000LL * 10000LL)
 
 class spinlock
 {
   LONG *locker;
   LONG val;
+  LONG setto;
+  void done (LONG what)
+  {
+    if (locker)
+      {
+	InterlockedExchange (locker, what);
+	locker = NULL;
+      }
+  }
+  long long time ()
+  {
+    LARGE_INTEGER t;
+    if (NtQuerySystemTime (&t) == STATUS_SUCCESS)
+      return get_ll (t);
+    return 0LL;
+  }
 public:
-  spinlock (LONG& locktest, LONGLONG timeout):
-    locker (&locktest)
+  spinlock (LONG& locktest, LONG wanted_val = 1, LONGLONG timeout = SPINLOCK_WAIT):
+    locker (&locktest), setto (wanted_val)
   {
-    if ((val = locktest) == 1)
-      return;
-    LONGLONG then = gtod.msecs ();
-    for (;;)
+    /* Quick test to see if we're already initialized */
+    if ((val = locktest) == wanted_val)
+      locker = NULL;
+    /* Slightly less quick test to see if we are the first cygwin process */
+    else if ((val = InterlockedExchange (locker, -1)) == 0)
+      /* We're armed and dangerous */;
+    else if (val == wanted_val)
+      done (val);	/* This was initialized while we weren't looking */
+    else
       {
-	if ((val = InterlockedExchange (locker, -1)) != -1
-	    || (gtod.msecs () - then) >= timeout)
-	  break;
-	yield ();
+	long long then = time ();
+	/* Loop waiting for some other process to set locktest to something
+	   other than -1, indicating that initialization has finished.  Or,
+	   wait a default of 15 seconds for that to happen and, if it doesn't
+	   just grab the lock ourselves. */
+	while ((val = InterlockedExchange (locker, -1)) == -1
+	       && (time () - then) < timeout)
+	  yield ();
+	/* Reset the lock back to wanted_value under the assumption that is
+	   what caused the above loop to kick out.  */
+	if (val == -1)
+	  val = 0;	/* Timed out.  We'll initialize things ourselves. */
+	else
+	  done (val);	/* Put back whatever was there before, assuming that
+			   it is actually wanted_val. */
       }
   }
-  ~spinlock () {InterlockedExchange (locker, 1);}
+  ~spinlock () {done (setto);}
   operator LONG () const {return val;}
+  /* FIXME: This should be handled in a more general fashion, probably by
+     establishing a linked list of spinlocks which are freed on process exit. */
+  void multiple_cygwin_problem (const char *w, unsigned m, unsigned v)
+  {
+    done (val);
+    ::multiple_cygwin_problem (w, m, v);
+  }
 };
 
 #endif /*_SPINLOCK_H*/
-
diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
index 6f9260fcd..f7e55cce9 100644
--- a/winsup/cygwin/syscalls.cc
+++ b/winsup/cygwin/syscalls.cc
@@ -2965,7 +2965,7 @@ seteuid32 (__uid32_t uid)
   groups.ischanged = FALSE;
   if (!issamesid)
     /* Recreate and fill out the user shared region for a new user. */
-    user_shared_create (true);
+    user_info::create (true);
   return 0;
 }