Cygwin: wincap: make capability flags readonly

So far the capability bits were stored in the .cygwin_dll_common
R/W section because we overwrite the is_server bit.  Just don't.
Move the bit to class wincapc instead and define all wincaps
bitfields const.

Fixes: 8937c103ed ("* wincap.cc (all wincaps): Store in .cygwin_dll_common section same as wincap.  Add comment to explain why.")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/local_includes/wincap.h

@@ -16,7 +16,6 @@ struct wincaps
   /* The bitfields must be 8 byte aligned on x86_64, otherwise the bitfield
      ops generated by gcc are off by 4 bytes. */
   struct  __attribute__ ((aligned (8))) {
-    unsigned is_server						: 1;
     unsigned has_new_pebteb_region				: 1;
     unsigned has_unprivileged_createsymlink			: 1;
     unsigned has_precise_interrupt_time				: 1;
@@ -41,7 +40,8 @@ class wincapc
   SYSTEM_INFO		system_info;
   RTL_OSVERSIONINFOEXW	version;
   char			osnam[40];
-  void			*caps;
+  const void		*caps;
+  bool			_is_server;
 
 public:
   void init ();
@@ -67,7 +67,7 @@ public:
   {
     return DEFAULT_GUARD_PAGE_COUNT * page_size ();
   }
-  bool  IMPLEMENT (is_server)
+  bool  is_server () const { return _is_server; }
   bool	IMPLEMENT (has_new_pebteb_region)
   bool	IMPLEMENT (has_unprivileged_createsymlink)
   bool	IMPLEMENT (has_precise_interrupt_time)

winsup/cygwin/wincap.cc

@@ -13,15 +13,8 @@ details. */
 #include "ntdll.h"
 #include "memory_layout.h"
 
-/* CV, 2008-10-23: All wincapc's have to be in the .cygwin_dll_common section,
+static const wincaps wincap_8_1 = {
-   same as wincap itself.  Otherwise the capability changes made in
-   wincapc::init() are not propagated to any subsequently started process
-   in the same session.  I'm only writing this longish comment because I'm
-   puzzled that this has never been noticed before... */
-
-wincaps wincap_8_1 __attribute__((section (".cygwin_dll_common"), shared)) = {
   {
-    is_server:false,
     has_new_pebteb_region:false,
     has_unprivileged_createsymlink:false,
     has_precise_interrupt_time:false,
@@ -41,9 +34,8 @@ wincaps wincap_8_1 __attribute__((section (".cygwin_dll_common"), shared)) = {
   },
 };
 
-wincaps  wincap_10_1507 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps  wincap_10_1507 = {
   {
-    is_server:false,
     has_new_pebteb_region:false,
     has_unprivileged_createsymlink:false,
     has_precise_interrupt_time:true,
@@ -63,9 +55,8 @@ wincaps  wincap_10_1507 __attribute__((section (".cygwin_dll_common"), shared))
   },
 };
 
-wincaps  wincap_10_1607 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps  wincap_10_1607 = {
   {
-    is_server:false,
     has_new_pebteb_region:false,
     has_unprivileged_createsymlink:false,
     has_precise_interrupt_time:true,
@@ -85,9 +76,8 @@ wincaps  wincap_10_1607 __attribute__((section (".cygwin_dll_common"), shared))
   },
 };
 
-wincaps wincap_10_1703 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps wincap_10_1703 = {
   {
-    is_server:false,
     has_new_pebteb_region:true,
     has_unprivileged_createsymlink:true,
     has_precise_interrupt_time:true,
@@ -107,9 +97,8 @@ wincaps wincap_10_1703 __attribute__((section (".cygwin_dll_common"), shared)) =
   },
 };
 
-wincaps wincap_10_1709 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps wincap_10_1709 = {
   {
-    is_server:false,
     has_new_pebteb_region:true,
     has_unprivileged_createsymlink:true,
     has_precise_interrupt_time:true,
@@ -129,9 +118,8 @@ wincaps wincap_10_1709 __attribute__((section (".cygwin_dll_common"), shared)) =
   },
 };
 
-wincaps wincap_10_1803 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps wincap_10_1803 = {
   {
-    is_server:false,
     has_new_pebteb_region:true,
     has_unprivileged_createsymlink:true,
     has_precise_interrupt_time:true,
@@ -151,9 +139,8 @@ wincaps wincap_10_1803 __attribute__((section (".cygwin_dll_common"), shared)) =
   },
 };
 
-wincaps wincap_10_1809 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps wincap_10_1809 = {
   {
-    is_server:false,
     has_new_pebteb_region:true,
     has_unprivileged_createsymlink:true,
     has_precise_interrupt_time:true,
@@ -173,9 +160,8 @@ wincaps wincap_10_1809 __attribute__((section (".cygwin_dll_common"), shared)) =
   },
 };
 
-wincaps wincap_10_1903 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps wincap_10_1903 = {
   {
-    is_server:false,
     has_new_pebteb_region:true,
     has_unprivileged_createsymlink:true,
     has_precise_interrupt_time:true,
@@ -195,9 +181,8 @@ wincaps wincap_10_1903 __attribute__((section (".cygwin_dll_common"), shared)) =
   },
 };
 
-wincaps wincap_10_2004 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps wincap_10_2004 = {
   {
-    is_server:false,
     has_new_pebteb_region:true,
     has_unprivileged_createsymlink:true,
     has_precise_interrupt_time:true,
@@ -217,9 +202,8 @@ wincaps wincap_10_2004 __attribute__((section (".cygwin_dll_common"), shared)) =
   },
 };
 
-wincaps wincap_11 __attribute__((section (".cygwin_dll_common"), shared)) = {
+static const wincaps wincap_11 = {
   {
-    is_server:false,
     has_new_pebteb_region:true,
     has_unprivileged_createsymlink:true,
     has_precise_interrupt_time:true,
@@ -284,7 +268,7 @@ wincapc::init ()
 	  caps = & wincap_10_1507;
     }
 
-  ((wincaps *)caps)->is_server = (version.wProductType != VER_NT_WORKSTATION);
+  _is_server = (version.wProductType != VER_NT_WORKSTATION);
 
   __small_sprintf (osnam, "NT-%d.%d", version.dwMajorVersion,
 		   version.dwMinorVersion);