* dcrt0.cc (init_windows_system_directory): Record system_wow64_directory

information.
* exceptions.cc (_cygtls::inside_kernel): Modernize comment.  Consider
executing a DLL from the Wow64 directory as being "in the kernel".
(_cygtls::call_signal_handler): For now, only deal with main_tls signals if
main_tls is known to be executing in the cygwin DLL.  To more closely emulate
linux, consider the operation to be restartable if not executing in the main
thread.
* globals.cc (windows_system_directory): Remove NO_COPY.
(windows_system_directory_length): Ditto.
(system_wow64_directory): New variable.
(system_wow64_directory_length): Ditto.
* select.cc (cygwin_select): Don't issue a EINTR on non-main threads since that
seems to be what Linux does.  Add missing break to signal case/switch.
(select_stuff::wait): Don't issue a EINTR on non-main threads since that seems
to be what Linux does.  Remove now-unneeded accommodation for
WAIT_IO_COMPLETION.  Add a comment.
* sigproc.h (cygwait): Ditto.  Don't return if signal_received noticed and it's
not the main thread.
* signal.cc (sigprocmask): Add standard syscall debug stuff.
* thread.cc (pthread_sigmask): Ditto.

1 files changed, 17 insertions, 6 deletions

diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index 5364e4dd8..b6392acf2 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -638,12 +638,23 @@ child_info_spawn::handle_spawn ()
 static void
 init_windows_system_directory ()
 {
-  windows_system_directory_length =
-	GetSystemDirectoryW (windows_system_directory, MAX_PATH);
-  if (windows_system_directory_length == 0)
-    api_fatal ("can't find windows system directory");
-  windows_system_directory[windows_system_directory_length++] = L'\\';
-  windows_system_directory[windows_system_directory_length] = L'\0';
+  if (!windows_system_directory_length)
+    {
+      windows_system_directory_length =
+	    GetSystemDirectoryW (windows_system_directory, MAX_PATH);
+      if (windows_system_directory_length == 0)
+	api_fatal ("can't find windows system directory");
+      windows_system_directory[windows_system_directory_length++] = L'\\';
+      windows_system_directory[windows_system_directory_length] = L'\0';
+
+      system_wow64_directory_length =
+	GetSystemWow64DirectoryW (system_wow64_directory, MAX_PATH);
+      if (system_wow64_directory_length)
+	{
+	  system_wow64_directory[system_wow64_directory_length++] = L'\\';
+	  system_wow64_directory[system_wow64_directory_length] = L'\0';
+	}
+    }
 }
 
 static bool NO_COPY wow64_respawn = false;