Fix various OS-related comments

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/cygheap.h

@@ -207,17 +207,16 @@ enum fcwd_version_t {
   FCWD_W8
 };
 
-/* This class is used to store the CWD starting with Windows Vista.
+/* This class is used to store the CWD.  The CWD storage in the
-   The CWD storage in the RTL_USER_PROCESS_PARAMETERS block is only
+   RTL_USER_PROCESS_PARAMETERS block is only an afterthought now.  The actual
-   an afterthought now.  The actual CWD storage is a FAST_CWD structure
+   CWD storage is a FAST_CWD structure which is allocated on the process heap.
-   which is allocated on the process heap.  The new method only requires
+   The new method only requires minimal locking and it's much more multi-thread
-   minimal locking and it's much more multi-thread friendly.  Presumably
+   friendly.  Presumably it minimizes contention when accessing the CWD.
-   it minimizes contention when accessing the CWD.
    The class fcwd_access_t is supposed to encapsulate the gory implementation
    details depending on OS version from the calling functions.
    The layout of all structures has been tested on 32 and 64 bit. */
 class fcwd_access_t {
-  /* This is the layout used in Windows 8. */
+  /* This is the layout used in Windows 8 and later. */
   struct FAST_CWD_8 {
     LONG           ReferenceCount;	/* Only release when this is 0. */
     HANDLE         DirectoryHandle;

winsup/cygwin/dll_init.cc

@@ -523,13 +523,12 @@ void dll_list::load_after_fork_impl (HANDLE parent, dll* d, int retries)
      We DONT_RESOLVE_DLL_REFERENCES at first in case the DLL lands in
      the wrong spot;
 
-     NOTE: This step skips DLLs which loaded at their preferred
+     NOTE: This step skips DLLs which loaded at their preferred address in
-     address in the parent because they should behave (we already
+     the parent because they should behave (we already verified that their
-     verified that their preferred address in the child is
+     preferred address in the child is available). However, this may fail
-     available). However, this may fail on a Vista/Win7 machine with
+     with ASLR active, because the ASLR base address will usually not equal
-     ASLR active, because the ASLR base address will usually not equal
+     the preferred base recorded in the dll. In this case, we should make
-     the preferred base recorded in the dll. In this case, we should
+     the LoadLibraryExW call unconditional.
-     make the LoadLibraryExW call unconditional.
    */
   for ( ; d; d = dlls.inext ())
     if (d->handle != d->preferred_base)

winsup/cygwin/dtable.cc

@@ -304,8 +304,8 @@ dtable::init_std_file_from_handle (int fd, HANDLE handle)
 	dev.parse (name);
       else if (strcmp (name, ":sock:") == 0
 	       /* NtQueryObject returns an error when called on an LSP socket
-		  handle.  While fdsock now tries to fetch the underlying
+		  handle.  fdsock tries to fetch the underlying base socket,
-		  base socket, this only works on Vista and later. */
+		  but this might fail. */
 	       || (strcmp (name, unknown_file) == 0
 		   && !::getsockopt ((SOCKET) handle, SOL_SOCKET, SO_RCVBUF,
 				     (char *) &rcv, &len)))

winsup/cygwin/fhandler_disk_file.cc

@@ -1888,12 +1888,11 @@ fhandler_disk_file::opendir (int fd)
 
 	     NFS clients hide dangling symlinks from directory queries,
 	     unless you use the FileNamesInformation info class.
-	     On newer NFS clients (>=Vista) FileIdBothDirectoryInformation
+	     FileIdBothDirectoryInformation works fine, but only if the NFS
-	     works fine, but only if the NFS share is mounted to a drive
+	     share is mounted to a drive letter.  TODO: We don't test that
-	     letter.  TODO: We don't test that here for now, but it might
+	     here for now, but it might be worth to test if there's a speed
-	     be worth to test if there's a speed gain in using
+	     gain in using FileIdBothDirectoryInformation, because it doesn't
-	     FileIdBothDirectoryInformation, because it doesn't require to
+	     require to open the file to read the inode number. */
-	     open the file to read the inode number. */
 	  if (pc.hasgood_inode ())
 	    {
 	      dir->__flags |= dirent_set_d_ino;

winsup/cygwin/heap.cc

@@ -38,11 +38,11 @@ eval_start_address ()
      So we let the heap start at 0x6:00000000L. */
   uintptr_t start_address = 0x600000000L;
 #else
-  /* Starting with Vista, Windows performs heap ASLR.  This spoils the entire
+  /* Windows performs heap ASLR.  This spoils the entire region below
-     region below 0x20000000 for us, because that region is used by Windows
+     0x20000000 for us, because that region is used by Windows to randomize
-     to randomize heap and stack addresses.  Therefore we put our heap into a
+     heap and stack addresses.  Therefore we put our heap into a safe region
-     safe region starting at 0x20000000.  This should work right from the start
+     starting at 0x20000000.  This should work right from the start in 99%
-     in 99% of the cases. */
+     of the cases. */
   uintptr_t start_address = 0x20000000L;
   if ((uintptr_t) NtCurrentTeb () >= 0xbf000000L)
     {

winsup/cygwin/mount.cc

@@ -385,7 +385,7 @@ fs_info::update (PUNICODE_STRING upath, HANDLE in_vol)
 	     and stuff like that. */
 	  && !is_mvfs (RtlEqualUnicodePathPrefix (&fsname, &ro_u_mvfs, FALSE))
 	  /* NWFS == Novell Netware FS.  Broken info class, see below. */
-	  /* NcFsd == Novell Netware FS via own driver since Windows Vista. */
+	  /* NcFsd == Novell Netware FS via own driver. */
 	  && !is_nwfs (RtlEqualUnicodeString (&fsname, &ro_u_nwfs, FALSE))
 	  && !is_ncfsd (RtlEqualUnicodeString (&fsname, &ro_u_ncfsd, FALSE))
 	  /* UNIXFS == TotalNet Advanced Server (TAS).  Doesn't support

winsup/cygwin/net.cc

@@ -608,7 +608,7 @@ fdsock (cygheap_fdmanip& fd, const device *dev, SOCKET soc)
      handle inheritance.  An explanation for this weird behaviour would
      be nice, though.
 
-     NOTE 2.  Testing on x86_64 (XP, Vista, 2008 R2, W8) indicates that
+     NOTE 2.  Testing on x86_64 (Vista, 2008 R2, W8) indicates that
      this is no problem on 64 bit.  So we set the default buffer size to
      the default values in current 3.x Linux versions.
 
@@ -1821,8 +1821,8 @@ get_adapters_addresses (PIP_ADAPTER_ADDRESSES *pa_ret, ULONG family)
   DWORD ret;
   gaa_wa param = { family, pa_ret };
 
-  if ((uintptr_t) &param >= (uintptr_t) 0x80000000L
+  if (wincap.has_gaa_largeaddress_bug ()
-      && wincap.has_gaa_largeaddress_bug ())
+      && (uintptr_t) &param >= (uintptr_t) 0x80000000L)
     {
       /* In Windows Vista and Windows 7 under WOW64, GetAdaptersAddresses fails
 	 if it's running in a thread with a stack located in the large address
@@ -3371,8 +3371,8 @@ cygwin_getaddrinfo (const char *hostname, const char *servname,
 			| AI_NUMERICSERV | AI_ADDRCONFIG | AI_V4MAPPED
 			| AI_IDN_MASK)))
 	return EAI_BADFLAGS;
-      /* AI_NUMERICSERV is not supported prior to Windows Vista.  We just check
+      /* AI_NUMERICSERV is not supported "by Microsoft providers".  We just
-	 the servname parameter by ourselves here. */
+	 check the servname parameter by ourselves here. */
       if (hints && (hints->ai_flags & AI_NUMERICSERV))
 	{
 	  char *p;

winsup/cygwin/path.cc

@@ -2889,9 +2889,7 @@ restart:
 
       /* Reparse points are potentially symlinks.  This check must be
 	 performed before checking the SYSTEM attribute for sysfile
-	 symlinks, since reparse points can have this flag set, too.
+	 symlinks, since reparse points can have this flag set, too. */
-	 For instance, Vista starts to create a couple of reparse points
-	 with SYSTEM and HIDDEN flags set. */
       if ((fileattr & FILE_ATTRIBUTE_REPARSE_POINT))
 	{
 	  res = check_reparse_point (h, fs.is_remote_drive ());
@@ -3974,13 +3972,9 @@ fcwd_access_t::SetVersionFromPointer (PBYTE buf_p, bool is_buffer)
 }
 
 /* This function scans the code in ntdll.dll to find the address of the
-   global variable used to access the CWD starting with Vista.  While the
+   global variable used to access the CWD.  While the pointer is global,
-   pointer is global, it's not exported from the DLL, unfortunately.
+   it's not exported from the DLL, unfortunately.  Therefore we have to
-   Therefore we have to use some knowledge to figure out the address.
+   use some knowledge to figure out the address. */
-
-   This code has been tested on Vista 32/64 bit, Server 2008 32/64 bit,
-   Windows 7 32/64 bit, Server 2008 R2 (which is only 64 bit anyway),
-   Windows 8 32/64 bit, Windows 8.1 32/64 bit, and Server 2012 R2. */
 
 #ifdef __x86_64__
 
@@ -4240,9 +4234,8 @@ cwdstuff::override_win32_cwd (bool init, ULONG old_dismount_count)
     fast_cwd_ptr = find_fast_cwd ();
   if (fast_cwd_ptr)
     {
-      /* Default method starting with Vista.  If we got a valid value for
+      /* If we got a valid value for fast_cwd_ptr, we can simply replace
-	 fast_cwd_ptr, we can simply replace the RtlSetCurrentDirectory_U
+	 the RtlSetCurrentDirectory_U function entirely. */
-	 function entirely, just as on pre-Vista. */
       PVOID heap = peb.ProcessHeap;
       /* First allocate a new fcwd_access_t structure on the heap.
 	 The new fcwd_access_t structure is 4 byte bigger than the old one,
@@ -4274,14 +4267,13 @@ cwdstuff::override_win32_cwd (bool init, ULONG old_dismount_count)
     }
   else
     {
-      /* This is more a hack, and it's only used on Vista and later if we
+      /* This is more a hack, and it's only used if we failed to find the
-	 failed to find the fast_cwd_ptr value.  What we do here is to call
+	 fast_cwd_ptr value.  We call RtlSetCurrentDirectory_U and let it
-	 RtlSetCurrentDirectory_U and let it set up a new FAST_CWD
+	 set up a new FAST_CWD structure.  Afterwards, compute the address
-	 structure.  Afterwards, compute the address of that structure
+	 of that structure utilizing the fact that the buffer address in
-	 utilizing the fact that the buffer address in the user process
+	 the user process parameter block is actually pointing to the buffer
-	 parameter block is actually pointing to the buffer in that
+	 in that FAST_CWD structure.  Then replace the directory handle in
-	 FAST_CWD structure.  Then replace the directory handle in that
+	 that structure with our own handle and close the original one.
-	 structure with our own handle and close the original one.
 
 	 Note that the call to RtlSetCurrentDirectory_U also closes our
 	 old dir handle, so there won't be any handle left open.
@@ -4374,13 +4366,6 @@ cwdstuff::set (path_conv *nat_cwd, const char *posix_cwd)
      - SetCurrentDirectory can naturally not work on virtual Cygwin paths
        like /proc or /cygdrive.
 
-     Unfortunately, even though we have access to the Win32 process parameter
-     block, we can't just replace the directory handle.  Starting with Vista,
-     the handle is used elsewhere, and just replacing the handle in the process
-     parameter block shows quite surprising results.
-     FIXME: If we ever find a *safe* way to replace the directory handle in
-     the process parameter block, we're back in business.
-
      Nevertheless, doing entirely without SetCurrentDirectory is not really
      feasible, because it breaks too many mixed applications using the Win32
      API.
@@ -4401,11 +4386,11 @@ cwdstuff::set (path_conv *nat_cwd, const char *posix_cwd)
     }
 
   /* Memorize old DismountCount before opening the dir.  This value is
-     stored in the FAST_CWD structure on Vista and later.  It would be
+     stored in the FAST_CWD structure.  It would be simpler to fetch the
-     simpler to fetch the old DismountCount in override_win32_cwd, but
+     old DismountCount in override_win32_cwd, but Windows also fetches
-     Windows also fetches it before opening the directory handle.  It's
+     it before opening the directory handle.  It's not quite clear if
-     not quite clear if that's really required, but since we don't know
+     that's really required, but since we don't know the side effects of
-     the side effects of this action, we better follow Windows' lead. */
+     this action, we better follow Windows' lead. */
   ULONG old_dismount_count = SharedUserData.DismountCount;
   /* Open a directory handle with FILE_OPEN_FOR_BACKUP_INTENT and with all
      sharing flags set.  The handle is right now used in exceptions.cc only,

winsup/cygwin/sec_auth.cc

@@ -36,12 +36,11 @@ issetugid (void)
   return cygheap->user.issetuid () ? 1 : 0;
 }
 
-/* Starting with Windows Vista, the token returned by system functions
+/* The token returned by system functions is a restricted token.  The full
-   is a restricted token.  The full admin token is linked to it and can
+   admin token is linked to it and can be fetched with NtQueryInformationToken.
-   be fetched with NtQueryInformationToken.  This function returns the original
+   This function returns the elevated token if available, the original token
-   token on pre-Vista, and the elevated token on Vista++ if it's available,
+   otherwise.  The token handle is also made inheritable since that's necessary
-   the original token otherwise.  The token handle is also made inheritable
+   anyway. */
-   since that's necessary anyway. */
 static HANDLE
 get_full_privileged_inheritable_token (HANDLE token)
 {
@@ -219,7 +218,7 @@ get_user_profile_directory (PCWSTR sidstr, PWCHAR path, SIZE_T path_len)
 }
 
 /* Load user profile if it's not already loaded.  If the user profile doesn't
-   exist on the machine, and if we're running Vista or later, try to create it. 
+   exist on the machine try to create it.
 
    Return a handle to the loaded user registry hive only if it got actually
    loaded here, not if it already existed.  There's no reliable way to know
@@ -821,8 +820,8 @@ verify_token (HANDLE token, cygsid &usersid, user_groups &groups, bool *pintern)
 
       /* Check that all groups in the setgroups () list are in the token.
 	 A token created through ADVAPI should be allowed to contain more
-	 groups than requested through setgroups(), especially since Vista
+	 groups than requested through setgroups(), especially since the
-	 and the addition of integrity groups. */
+	 addition of integrity groups. */
       memset (saw, 0, sizeof(saw));
       for (int gidx = 0; gidx < groups.sgsids.count (); gidx++)
 	{

winsup/cygwin/sec_helper.cc

@@ -628,11 +628,6 @@ _recycler_sd (void *buf, bool users, bool dir)
     return NULL;
   RtlCreateSecurityDescriptor (psd, SECURITY_DESCRIPTOR_REVISION);
   PACL dacl = (PACL) (psd + 1);
-  /* Pre-Vista, the per-user recycler dir has a rather too complicated
-     ACL by default, which has distinct ACEs for inheritable and non-inheritable
-     permissions.  However, this ACL is practically equivalent to the ACL
-     created since Vista.  Therefore we simplify our job here and create the
-     pre-Vista permissions the same way as on Vista and later. */
   RtlCreateAcl (dacl, MAX_DACL_LEN (3), ACL_REVISION);
   RtlAddAccessAllowedAceEx (dacl, ACL_REVISION,
 			    dir ? SUB_CONTAINERS_AND_OBJECTS_INHERIT

winsup/cygwin/security.h

@@ -89,7 +89,6 @@ void uinfo_init ();
 #define SE_MANAGE_VOLUME_PRIVILEGE          28U
 #define SE_IMPERSONATE_PRIVILEGE            29U
 #define SE_CREATE_GLOBAL_PRIVILEGE          30U
-/* Starting with Vista */
 #define SE_TRUSTED_CREDMAN_ACCESS_PRIVILEGE 31U
 #define SE_RELABEL_PRIVILEGE                32U
 #define SE_INCREASE_WORKING_SET_PRIVILEGE   33U

winsup/cygwin/syscalls.cc

@@ -268,11 +268,11 @@ try_to_bin (path_conv &pc, HANDLE &fh, ACCESS_MASK access, ULONG flags)
      them into the recycler. */
   if (pfni->FileNameLength == 2) /* root dir. */
     goto out;
-  /* The recycler name on Vista and later is $Recycler.Bin by default.  If the
+  /* The recycler name is $Recycler.Bin by default.  If the recycler dir
-     recycler dir disappeared for some reason, the shell32.dll recreates the
+     disappeared for some reason, the shell32.dll recreates the directory in
-     directory in all upper case.  So, we never know beforehand if the dir
+     all upper case.  So, we never know beforehand if the dir is written in
-     is written in mixed case or in all upper case.  That's a problem when
+     mixed case or in all upper case.  That's a problem when using
-     using casesensitivity.  If the file handle given to FileRenameInformation
+     casesensitivity.  If the file handle given to FileRenameInformation
      has been opened casesensitive, the call also handles the path to the
      target dir casesensitive.  Rather then trying to find the right name
      of the recycler, we just reopen the file to move with OBJ_CASE_INSENSITIVE,
@@ -958,10 +958,10 @@ try_again:
 	     "Subsequently, the only legal operation by such a caller is
 	     to close the open file handle."
 
-	     FIXME? On Vista and later, we could use FILE_HARD_LINK_INFORMATION
+	     FIXME?  We could use FILE_HARD_LINK_INFORMATION to find all
-	     to find all hardlinks and use one of them to restore the R/O bit,
+	     hardlinks and use one of them to restore the R/O bit, after the
-	     after the NtClose, but before we stop the transaction.  This
+	     NtClose, but before we stop the transaction.  This avoids the
-	     avoids the aforementioned problem entirely . */
+	     aforementioned problem entirely . */
 	  else if (pc.is_lnk_symlink () && num_links > 1)
 	    NtSetAttributesFile (fh, pc.file_attributes ());
 	}
@@ -3219,9 +3219,9 @@ seteuid32 (uid_t uid)
 		       CW_TOKEN_RESTRICTED);
        setuid (getuid ());
 
-    Note that using the current uid is a requirement!  Starting with Windows
+    Note that using the current uid is a requirement!  We have restricted
-    Vista, we have restricted tokens galore (UAC), so this is really just
+    tokens galore (UAC), so this is really just a special case to restrict
-    a special case to restict your own processes to lesser rights. */
+    your own processes to lesser rights. */
   bool request_restricted_uid_switch = (uid == myself->uid
       && cygheap->user.ext_token_is_restricted);
   if (uid == myself->uid && !cygheap->user.groups.ischanged