[PATCH v4 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.

	* sysdeps/unix/sysv/linux/generic/bits/stat.h: Handle 64-bit ino_t types
	on 32-bit hosts.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/overflow.h: Likewise.
	* sysdeps/unix/sysv/linux/generic/xstat.c: Ensure __blkcnt_t == __blkcnt64_t
	if __INO_T_MATCHES_INO64_T is defined.
---
 sysdeps/unix/sysv/linux/generic/bits/stat.h            | 5 ++++-
 sysdeps/unix/sysv/linux/generic/wordsize-32/overflow.h | 4 ++++
 sysdeps/unix/sysv/linux/generic/xstat.c                | 5 +++++
 3 files changed, 13 insertions(+), 1 deletion(-)

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/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.  */
diff --git a/sysdeps/unix/sysv/linux/generic/xstat.c b/sysdeps/unix/sysv/linux/generic/xstat.c
index 75ceb9bc74b..ece14fc5838 100644
--- a/sysdeps/unix/sysv/linux/generic/xstat.c
+++ b/sysdeps/unix/sysv/linux/generic/xstat.c
@@ -28,6 +28,11 @@
 #include <sysdep.h>
 #include <sys/syscall.h>
 
+#if __INO_T_MATCHES_INO64_T
+_Static_assert (sizeof (__blkcnt_t) == sizeof (__blkcnt64_t),
+                "__blkcnt_t and __blkcnt64_t must match");
+#endif
+
 /* Get information about the file NAME in BUF.  */
 int
 __xstat (int vers, const char *name, struct stat *buf)
-- 
2.23.0