[PATCH v6 1/2] sysdeps/stat: Handle 64-bit ino_t types on 32-bit hosts

[Alistair Francis <alistair dot francis at wdc dot com>]

On a 32-bit platform with a 64-bit ino_t type (__INO_T_MATCHES_INO64_T
defined) we want to update the stat struct to remove the padding as it
isn't required. As we don't have the padding we also need to update the
overflow checker to not access the undefined members.
---
This change was tested by running user space tests for RV32 and RV64.

v6:
 - Update Makefile to build assert
v4:
 - Move the assert to: sysdeps/unix/sysv/linux/generic/stat-check.c
 - Add a comment around the assert
v3:
 - Don't use brackets around the defined
v2:
 - Change to if defined instead of if == 1

 sysdeps/unix/sysv/linux/generic/Makefile      |  2 +-
 sysdeps/unix/sysv/linux/generic/bits/stat.h   |  5 +++-
 sysdeps/unix/sysv/linux/generic/stat-check.c  | 29 +++++++++++++++++++
 .../sysv/linux/generic/wordsize-32/overflow.h |  4 +++
 4 files changed, 38 insertions(+), 2 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/generic/stat-check.c

diff --git a/sysdeps/unix/sysv/linux/generic/Makefile b/sysdeps/unix/sysv/linux/generic/Makefile
index 7e27e797726..124f83a0abd 100644
--- a/sysdeps/unix/sysv/linux/generic/Makefile
+++ b/sysdeps/unix/sysv/linux/generic/Makefile
@@ -1,3 +1,3 @@
 ifeq ($(subdir),misc)
-sysdep_routines += epoll_create inotify_init
+sysdep_routines += epoll_create inotify_init stat-check
 endif
diff --git a/sysdeps/unix/sysv/linux/generic/bits/stat.h b/sysdeps/unix/sysv/linux/generic/bits/stat.h
index 1565f3f8248..34c455ed786 100644
--- a/sysdeps/unix/sysv/linux/generic/bits/stat.h
+++ b/sysdeps/unix/sysv/linux/generic/bits/stat.h
@@ -42,7 +42,10 @@
 
 #if defined __USE_FILE_OFFSET64
 # define __field64(type, type64, name) type64 name
-#elif __WORDSIZE == 64
+#elif __WORDSIZE == 64 || defined __INO_T_MATCHES_INO64_T
+# if defined __INO_T_MATCHES_INO64_T && !defined __OFF_T_MATCHES_OFF64_T
+#  error "ino_t and off_t must both be the same type"
+# endif
 # define __field64(type, type64, name) type name
 #elif __BYTE_ORDER == __LITTLE_ENDIAN
 # define __field64(type, type64, name) \
diff --git a/sysdeps/unix/sysv/linux/generic/stat-check.c b/sysdeps/unix/sysv/linux/generic/stat-check.c
new file mode 100644
index 00000000000..302d2e8c28a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/generic/stat-check.c
@@ -0,0 +1,29 @@
+/* Copyright (C) 2011-2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Alistair Francis <alistair.francis@wdc.com> 2019
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sys/stat.h>
+#include <bits/typesizes.h>
+
+/* This is due to the layout code in bits/stat.h and the overflow handling in
+   wordsize-32/overflow.h, requiring either all or none of the three types
+   concerned to have padding.  */
+
+#if defined __INO_T_MATCHES_INO64_T
+_Static_assert (sizeof (__blkcnt_t) == sizeof (__blkcnt64_t),
+                "__blkcnt_t and __blkcnt64_t must match");
+#endif
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/overflow.h b/sysdeps/unix/sysv/linux/generic/wordsize-32/overflow.h
index 45efcd8fd34..66546b07ccd 100644
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/overflow.h
+++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/overflow.h
@@ -36,12 +36,16 @@ static inline off_t lseek_overflow (loff_t res)
 
 static inline int stat_overflow (struct stat *buf)
 {
+#if defined __INO_T_MATCHES_INO64_T
+  return 0;
+#else
   if (buf->__st_ino_pad == 0 && buf->__st_size_pad == 0
       && buf->__st_blocks_pad == 0)
     return 0;
 
   __set_errno (EOVERFLOW);
   return -1;
+#endif
 }
 
 /* Note that f_files and f_ffree may validly be a sign-extended -1.  */
-- 
2.23.0