Only define loff_t for __USE_MISC (bug 14553)

Only define loff_t for __USE_MISC (bug 14553)

[Joseph Myers]

Bug 14553 reports that sys/types.h defines loff_t unconditionally,
despite it not being part of any supported standard.  This is
permitted by the POSIX *_t reservation, but as a
quality-of-implementation issue it's still best not to define it
except for __USE_MISC.  This patch conditions the definition
accordingly, updating a macro in sysdeps/unix/sysv/linux/sys/quota.h
to use __loff_t so it still works even if __USE_MISC is not defined.

codesearch.debian.net suggests there are quite a lot of loff_t uses
outside glibc, but it might well make sense to change all (few) uses
of loff_t or __loff_t inside glibc to use off64_t or __off64_t
instead, leaving only the definitions, treating this name as
obsolescent.

Tested for x86_64.

2018-02-01  Joseph Myers  <joseph@codesourcery.com>

	[BZ #14553]
	* posix/sys/types.h (loff_t): Only define for [__USE_MISC].
	* sysdeps/unix/sysv/linux/sys/quota.h (dqoff): Use __loff_t
	instead of loff_t.

diff --git a/posix/sys/types.h b/posix/sys/types.h
index a9e0005..e8d51a1 100644
--- a/posix/sys/types.h
+++ b/posix/sys/types.h
@@ -39,9 +39,8 @@ typedef __u_quad_t u_quad_t;
 typedef __fsid_t fsid_t;
 #  define __u_char_defined
 # endif
-#endif
-
 typedef __loff_t loff_t;
+#endif
 
 #ifndef __ino_t_defined
 # ifndef __USE_FILE_OFFSET64
diff --git a/sysdeps/unix/sysv/linux/sys/quota.h b/sysdeps/unix/sysv/linux/sys/quota.h
index c2a0aaa..23f569e 100644
--- a/sysdeps/unix/sysv/linux/sys/quota.h
+++ b/sysdeps/unix/sysv/linux/sys/quota.h
@@ -114,7 +114,7 @@ struct dqblk
 #define	dq_btime	dq_dqb.dqb_btime
 #define	dq_itime	dq_dqb.dqb_itime
 
-#define dqoff(UID)      ((loff_t)((UID) * sizeof (struct dqblk)))
+#define dqoff(UID)      ((__loff_t)((UID) * sizeof (struct dqblk)))
 
 /* Old name for struct if_dqinfo.  */
 struct dqinfo

-- 
Joseph S. Myers
joseph@codesourcery.com

Ping Re: Only define loff_t for __USE_MISC (bug 14553)

[Joseph Myers]

Ping.  This patch 
<https://sourceware.org/ml/libc-alpha/2018-02/msg00034.html> is pending 
review.

-- 
Joseph S. Myers
joseph@codesourcery.com

Re: Only define loff_t for __USE_MISC (bug 14553)

[Florian Weimer]

On 02/01/2018 09:36 PM, Joseph Myers wrote:
> 	[BZ #14553]
> 	* posix/sys/types.h (loff_t): Only define for [__USE_MISC].
> 	* sysdeps/unix/sysv/linux/sys/quota.h (dqoff): Use __loff_t
> 	instead of loff_t.

Looks okay.

Thanks,
Florian