[newlib-cygwin/main] Cygwin: use new XATTR_{NAME, SIZE}_MAX instead of MAX_EA_{NAME, VALUE}_LEN

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=048031501043e61ca31713b92ce2190213c7fb21

commit 048031501043e61ca31713b92ce2190213c7fb21
Author:     Philippe Cerfon <philcerf@gmail.com>
AuthorDate: Tue Jun 6 02:52:49 2023 +0200
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Fri Jun 16 21:44:41 2023 +0200

    Cygwin: use new XATTR_{NAME,SIZE}_MAX instead of MAX_EA_{NAME,VALUE}_LEN
    
    Signed-off-by: Philippe Cerfon <philcerf@gmail.com>

Diff:
---
 winsup/cygwin/ntea.cc | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/winsup/cygwin/ntea.cc b/winsup/cygwin/ntea.cc
index a400fcb2b302..70815649c374 100644
--- a/winsup/cygwin/ntea.cc
+++ b/winsup/cygwin/ntea.cc
@@ -17,9 +17,11 @@ details. */
 #include "tls_pbuf.h"
 #include <stdlib.h>
 #include <attr/xattr.h>
+#include <cygwin/limits.h>
 
-#define MAX_EA_NAME_LEN    256
-#define MAX_EA_VALUE_LEN 65536
+/* On storage the `user.` prefix is not included but the terminating null byte
+   is needed.*/
+#define _XATTR_NAME_MAX_ONDISK_ (XATTR_NAME_MAX - strlen("user.") + 1)
 
 /* At least one maximum sized entry fits.
    CV 2014-04-04: NtQueryEaFile function chokes on buffers bigger than 64K
@@ -27,13 +29,13 @@ details. */
 		  on a remote share, at least on Windows 7 and later.
 		  In theory the buffer should have a size of
 
-		    sizeof (FILE_FULL_EA_INFORMATION) + MAX_EA_NAME_LEN
-		    + MAX_EA_VALUE_LEN
+		    sizeof (FILE_FULL_EA_INFORMATION) + _XATTR_NAME_MAX_ONDISK_
+		    + XATTR_SIZE_MAX
 
 		  (65804 bytes), but we're opting for simplicity here, and
 		  a 64K buffer has the advantage that we can use a tmp_pathbuf
 		  buffer, rather than having to alloca 64K from stack. */
-#define EA_BUFSIZ MAX_EA_VALUE_LEN
+#define EA_BUFSIZ XATTR_SIZE_MAX
 
 #define NEXT_FEA(p) ((PFILE_FULL_EA_INFORMATION) (p->NextEntryOffset \
 		     ? (char *) p + p->NextEntryOffset : NULL))
@@ -55,7 +57,7 @@ read_ea (HANDLE hdl, path_conv &pc, const char *name, char *value, size_t size)
      returns the last EA entry of the file infinitely.  Even utilizing the
      optional EaIndex only helps marginally.  If you use that, the last
      EA in the file is returned twice. */
-  char lastname[MAX_EA_NAME_LEN];
+  char lastname[_XATTR_NAME_MAX_ONDISK_];
 
   __try
     {
@@ -95,7 +97,7 @@ read_ea (HANDLE hdl, path_conv &pc, const char *name, char *value, size_t size)
 	      __leave;
 	    }
 
-	  if ((nlen = strlen (name)) >= MAX_EA_NAME_LEN)
+	  if ((nlen = strlen (name)) >= _XATTR_NAME_MAX_ONDISK_)
 	    {
 	      set_errno (EINVAL);
 	      __leave;
@@ -197,7 +199,7 @@ read_ea (HANDLE hdl, path_conv &pc, const char *name, char *value, size_t size)
 		  /* For compatibility with Linux, we always prepend "user." to
 		     the attribute name, so effectively we only support user
 		     attributes from a application point of view. */
-		  char tmpbuf[MAX_EA_NAME_LEN * 2];
+		  char tmpbuf[_XATTR_NAME_MAX_ONDISK_ * 2];
 		  char *tp = stpcpy (tmpbuf, "user.");
 		  stpcpy (tp, fea->EaName);
 		  /* NTFS stores all EA names in uppercase unfortunately.  To
@@ -297,7 +299,7 @@ write_ea (HANDLE hdl, path_conv &pc, const char *name, const char *value,
       /* Skip "user." prefix. */
       name += 5;
 
-      if ((nlen = strlen (name)) >= MAX_EA_NAME_LEN)
+      if ((nlen = strlen (name)) >= _XATTR_NAME_MAX_ONDISK_)
 	{
 	  set_errno (EINVAL);
 	  __leave;