Cygwin: uname: add host machine tag to sysname

winsup/cygwin/local_includes/wincap.h

@@ -42,6 +42,8 @@ class wincapc
   RTL_OSVERSIONINFOEXW	version;
   char			osnam[40];
   const void		*caps;
+  USHORT		host_mach;
+  USHORT		cygwin_mach;
   bool			_is_server;
 
 public:
@@ -61,6 +63,8 @@ class wincapc
 		     { return (size_t) system_info.dwAllocationGranularity; }
   const char *osname () const { return osnam; }
   const DWORD build_number () const { return version.dwBuildNumber; }
+  const USHORT host_machine () const { return host_mach; }
+  const USHORT cygwin_machine () const { return cygwin_mach; }
 
 #define IMPLEMENT(cap) cap() const { return ((wincaps *) this->caps)->cap; }
 

winsup/cygwin/path.cc

@@ -4826,14 +4826,12 @@ find_fast_cwd_pointer ()
 static fcwd_access_t **
 find_fast_cwd ()
 {
-  USHORT emulated, hosted;
   fcwd_access_t **f_cwd_ptr;
 
-  /* First check if we're running in WOW64 on ARM64 emulating AMD64.  Skip
+  /* First check if we're running on an ARM64 system.  Skip
      fetching FAST_CWD pointer as long as there's no solution for finding
      it on that system. */
-  if (IsWow64Process2 (GetCurrentProcess (), &emulated, &hosted)
-      && hosted == IMAGE_FILE_MACHINE_ARM64)
+  if (wincap.host_machine () == IMAGE_FILE_MACHINE_ARM64)
     return NULL;
 
   /* Fetch the pointer but don't set the global fast_cwd_ptr yet.  First

winsup/cygwin/uname.cc

@@ -51,13 +51,27 @@ uname_x (struct utsname *name)
   __try
     {
       char buf[NI_MAXHOST + 1] ATTRIBUTE_NONSTRING;
+      int n;
 
       memset (name, 0, sizeof (*name));
       /* sysname */
       const char* sysname = get_sysname();
-      __small_sprintf (name->sysname, "%s_%s-%u",
-		       sysname,
-		       wincap.osname (), wincap.build_number ());
+      n = __small_sprintf (name->sysname, "%s_%s-%u",
+			   sysname,
+			   wincap.osname (), wincap.build_number ());
+      if (wincap.host_machine () != wincap.cygwin_machine ())
+	{
+	  switch (wincap.host_machine ())
+	    {
+	      case IMAGE_FILE_MACHINE_ARM64:
+		n = stpcpy (name->sysname + n, "-ARM64") - name->sysname;
+		break;
+	      default:
+		n += __small_sprintf (name->sysname + n, "-%04y",
+				      (int) wincap.host_machine ());
+		break;
+	    }
+	}
       /* nodename */
       memset (buf, 0, sizeof buf);
       cygwin_gethostname (buf, sizeof buf - 1);

winsup/cygwin/wincap.cc

@@ -235,9 +235,15 @@ static const wincaps wincap_11 = {
 
 wincapc wincap __attribute__((section (".cygwin_dll_common"), shared));
 
+extern IMAGE_DOS_HEADER
+__image_base__;
+
 void
 wincapc::init ()
 {
+  PIMAGE_NT_HEADERS ntheader;
+  USHORT emul_mach;
+
   if (caps)
     return;		// already initialized
 
@@ -282,4 +288,17 @@ wincapc::init ()
 
   __small_sprintf (osnam, "NT-%d.%d", version.dwMajorVersion,
 		   version.dwMinorVersion);
+
+  if (!IsWow64Process2 (GetCurrentProcess (), &emul_mach, &host_mach))
+    {
+      /* If IsWow64Process2 succeeded, it filled in host_mach.  Assume the only
+	 way it fails for the current process is that we're running on an OS
+	 version where it's not implemented yet.  As such, the only realistic
+	 option for host_mach is AMD64 */
+      host_mach = IMAGE_FILE_MACHINE_AMD64;
+    }
+
+  ntheader = (PIMAGE_NT_HEADERS)((LPBYTE) &__image_base__
+				 + __image_base__.e_lfanew);
+  cygwin_mach = ntheader->FileHeader.Machine;
 }