1999-12-13 Roland McGrath <roland@baalperazim.frob.com>

	Rewrite of a fix provided by Bill White <bill.white@griggsinst.com>:
	* fhandle.h (union diskfs_fhandle): Replaces struct diskfs_fhandle.
	Use a union element of char[28] to ensure size requirement.
	* fsys-getfile.c (diskfs_S_fsys_getfile): Update uses for new type.
	* file-getfh.c (diskfs_S_file_getfh): Likewise.

3 files changed, 34 insertions, 31 deletions

diff --git a/libdiskfs/fhandle.h b/libdiskfs/fhandle.h
index 9b1c7105..bd827d84 100644
--- a/libdiskfs/fhandle.h
+++ b/libdiskfs/fhandle.h
@@ -1,6 +1,6 @@
 /* File handle type (for nfs server support)
 
-   Copyright (C) 1997 Free Software Foundation
+   Copyright (C) 1997,99 Free Software Foundation, Inc.
 
    This file is part of the GNU Hurd.
 
@@ -9,7 +9,7 @@
    the Free Software Foundation; either version 2, or (at your option)
    any later version.
 
-   The GNU Hurd is distributed in the hope that it will be useful, 
+   The GNU Hurd is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
@@ -22,12 +22,15 @@
 #define __FHANDLE_H__
 
 /* Must be exactly 28 bytes long */
-struct diskfs_fhandle
+union diskfs_fhandle
 {
-  int filler1;
-  int cache_id;
-  long gen;
-  int filler2[28 - sizeof (int) + sizeof (int) + sizeof (long)];
+  unsigned char bytes[28];
+  struct
+  {
+    int pad1;
+    int cache_id;
+    unsigned int gen;
+  } data;
 };
 
 #endif /* __FHANDLE_H__ */
diff --git a/libdiskfs/file-getfh.c b/libdiskfs/file-getfh.c
index c755e911..a2dbb045 100644
--- a/libdiskfs/file-getfh.c
+++ b/libdiskfs/file-getfh.c
@@ -9,7 +9,7 @@
    the Free Software Foundation; either version 2, or (at your option)
    any later version.
 
-   The GNU Hurd is distributed in the hope that it will be useful, 
+   The GNU Hurd is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
@@ -29,30 +29,30 @@ error_t
 diskfs_S_file_getfh (struct protid *cred, char **fh, unsigned *fh_len)
 {
   struct node *node;
-  struct diskfs_fhandle *f;
+  union diskfs_fhandle *f;
 
   if (! cred)
     return EOPNOTSUPP;
 
   if (! idvec_contains (cred->user->uids, 0))
     return EPERM;
-  
+
+  assert (sizeof *f == sizeof f->bytes);
+
   node = cred->po->np;
 
   mutex_lock (&node->lock);
 
   if (*fh_len < sizeof (struct diskfs_fhandle))
-    *fh = mmap (0, sizeof (struct diskfs_fhandle), PROT_READ|PROT_WRITE, 
+    *fh = mmap (0, sizeof (struct diskfs_fhandle), PROT_READ|PROT_WRITE,
 		MAP_ANON, 0, 0);
-  *fh_len = sizeof (struct diskfs_fhandle);
-  
-  f = (struct diskfs_fhandle *)*fh;
+  *fh_len = sizeof *f;
 
-  f->cache_id = node->cache_id;
-  f->gen = node->dn_stat.st_gen;
+  f = (union diskfs_fhandle *) *fh;
 
-  f->filler1 = 0;
-  bzero (f->filler2, sizeof f->filler2);
+  bzero (f, sizeof *f);
+  f->data.cache_id = node->cache_id;
+  f->data.gen = node->dn_stat.st_gen;
 
   mutex_unlock (&node->lock);
 
diff --git a/libdiskfs/fsys-getfile.c b/libdiskfs/fsys-getfile.c
index 56766ed4..7d125304 100644
--- a/libdiskfs/fsys-getfile.c
+++ b/libdiskfs/fsys-getfile.c
@@ -1,6 +1,6 @@
 /* Return the file for a given handle (for nfs server support)
 
-   Copyright (C) 1997 Free Software Foundation
+   Copyright (C) 1997,99 Free Software Foundation, Inc.
 
    This file is part of the GNU Hurd.
 
@@ -9,7 +9,7 @@
    the Free Software Foundation; either version 2, or (at your option)
    any later version.
 
-   The GNU Hurd is distributed in the hope that it will be useful, 
+   The GNU Hurd is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
@@ -37,45 +37,45 @@ diskfs_S_fsys_getfile (mach_port_t fsys,
   int flags;
   error_t err;
   struct node *node;
-  struct diskfs_fhandle *f;
+  const union diskfs_fhandle *f;
   struct protid *new_cred;
   struct idvec *uvec, *gvec;
   struct iouser *user;
   struct port_info *pt =
     ports_lookup_port (diskfs_port_bucket, fsys, diskfs_control_class);
-  
+
   if (!pt)
     return EOPNOTSUPP;
 
-  if (handle_len != sizeof (struct diskfs_fhandle))
+  if (handle_len != sizeof *f)
     {
       ports_port_deref (pt);
       return EINVAL;
     }
 
-  f = (struct diskfs_fhandle *) handle;
+  f = (const union diskfs_fhandle *) handle;
 
-  err = diskfs_cached_lookup (f->cache_id, &node);
+  err = diskfs_cached_lookup (f->data.cache_id, &node);
   if (err)
     {
       ports_port_deref (pt);
       return err;
     }
 
-  if (node->dn_stat.st_gen != f->gen)
+  if (node->dn_stat.st_gen != f->data.gen)
     {
       diskfs_nput (node);
       ports_port_deref (pt);
       return ESTALE;
     }
-  
+
   uvec = make_idvec ();
   gvec = make_idvec ();
 
   idvec_set_ids (uvec, uids, nuids);
   idvec_set_ids (gvec, gids, ngids);
   user = iohelp_create_iouser (uvec, gvec);
-  
+
   flags = 0;
   if (! fshelp_access (&node->dn_stat, S_IREAD, user))
     flags |= O_READ;
@@ -88,12 +88,12 @@ diskfs_S_fsys_getfile (mach_port_t fsys,
 
   err = diskfs_create_protid (diskfs_make_peropen (node, flags, 0),
 			      user, &new_cred);
-  
+
   iohelp_free_iouser (user);
-  
+
   diskfs_nput (node);
   ports_port_deref (pt);
-  
+
   if (! err)
     {
       *file = ports_get_right (new_cred);