Handle unnecessary padding in getdents64.

The getdents64 syscall adds on 32-but platforms padding which isn't needed
and not included in the userlevel data structure definition.  We have to
avoid copying those padding bytes in the readdir64_r function.

ChangeLog

@@ -1,5 +1,11 @@
 2010-04-03  Ulrich Drepper  <drepper@redhat.com>
 
+	[BZ #11333]
+	* sysdeps/unix/readdir_r.c (__READDIR_R): Add support for platforms
+	which include unnecessary padding in d_reclen.
+	* sysdeps/unix/sysv/linux/i386/readdir64_r.c: Select work-around for
+	unnecessary padding.
+
 	[BZ #11387]
 	* sysdeps/unix/sysv/linux/ifaddrs.c (map_newlin): Don't abort on
 	unknown interface, return -1.

sysdeps/unix/readdir_r.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 1991,92,93,94,95,96,97,98,99,2000,02
+/* Copyright (C) 1991,92,93,94,95,96,97,98,99,2000,02,10
 	Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -113,7 +113,17 @@ __READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result)
   while (dp->d_ino == 0);
 
   if (dp != NULL)
-    *result = memcpy (entry, dp, reclen);
+    {
+#ifdef GETDENTS_64BIT_ALIGNED
+      /* The d_reclen value might include padding which is not part of
+	 the DIRENT_TYPE data structure.  */
+      reclen = MIN (reclen, sizeof (DIRENT_TYPE));
+#endif
+      *result = memcpy (entry, dp, reclen);
+#ifdef GETDENTS_64BIT_ALIGNED
+      entry->d_reclen = reclen;
+#endif
+    }
   else
     *result = NULL;
 

sysdeps/unix/sysv/linux/i386/readdir64_r.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 2000, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 2000, 2004, 2010 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -19,6 +19,7 @@
 #define __READDIR_R __readdir64_r
 #define __GETDENTS __getdents64
 #define DIRENT_TYPE struct dirent64
+#define GETDENTS_64BIT_ALIGNED 1
 
 #include <sysdeps/unix/readdir_r.c>