time_t on sparc64

[Harti Brandt]

Thanks for this info Bruce,

two questions however:


On Tue, 14 Oct 2003, Bruce Evans wrote:

BE>On Mon, 13 Oct 2003, Harti Brandt wrote:
BE>
BE>> I just discovered that time_t is 32-bit on sparc64. One of the problems
BE>> is that struct timeval is defined by Posix as
BE>>
BE>> struct timeval {
BE>> 	time_t	tv_secs;
BE>> 	suseconds_t tv_usecs;
BE>> };
BE>
BE>This is a bug in POSIX.  In BSD, tv_secs has type long which may be,
BE>and is different from time_t.

Why do you think this is a POSIX bug? Aren't we the odd man out? Now we
(and MacOS 10) require a workaround for thinks like

	printf("%s", ctime(tv.tv_secs));

which works perfect on other systems.

BE>
BE>> but _timeval.h has
BE>>
BE>> struct timeval {
BE>> 	long	tv_secs;
BE>> 	suseconds_t tv_usecs;
BE>> }
BE>>
BE>> This means, that our timeval is not Posix compatible. What is the reason
BE>> for time_t not beeing a long on sparc64?
BE>
BE>time_t was used in some data structures whose layout shouldn't be changed
BE>even for new arches.  Mainly in ufs in Lite2:
BE>
BE>%%%
BE>ffs/fs.h:	time_t 	 fs_time;		/* last time written */
BE>ffs/fs.h:	time_t	 cg_time;		/* time last written */
BE>ffs/fs.h:	time_t	 cg_time;		/* time last written */
BE>lfs/lfs.h:	time_t	bi_segcreate;		/* origin segment create time */
BE>ufs/quota.h:	time_t	  dqb_btime;		/* time limit for excessive disk use */
BE>ufs/quota.h:	time_t	  dqb_itime;		/* time limit for excessive files */
BE>%%%
BE>
BE>These are now:
BE>
BE>%%%
BE>ffs/fs.h:	int32_t  fs_old_time;		/* last time written */
BE>ffs/fs.h:	ufs_time_t fs_time;		/* last time written */
BE>ffs/fs.h:	int32_t  cg_old_time;		/* time last written */
BE>ffs/fs.h:	ufs_time_t cg_time;		/* time last written */
BE>/dev/null:	time_t	bi_segcreate;		/* origin segment create time */
BE>ufs/quota.h:	int32_t   dqb_btime;		/* time limit for excessive disk use */
BE>ufs/quota.h:	int32_t   dqb_itime;		/* time limit for excessive files */
BE>%%%
BE>
BE>I.e., int32_t is now not mispelled time_t in f^Hufs1 and Y2.038K bugs are
BE>fixed in ffs2 except for quotas.
BE>
BE>ffs2 also parametrizes timestamps in inodes better:
BE>
BE>%%%
BE>ufs/dinode.h:typedef int64_t ufs_time_t;
BE>ufs/dinode.h:	ufs_time_t	di_atime;	/*  32: Last access time. */
BE>ufs/dinode.h:	ufs_time_t	di_mtime;	/*  40: Last modified time. */
BE>ufs/dinode.h:	ufs_time_t	di_ctime;	/*  48: Last inode change time. */
BE>ufs/dinode.h:	ufs_time_t	di_birthtime;	/*  56: Inode creation time. */
BE>ufs/dinode.h:	int32_t		di_mtimensec;	/*  64: Last modified time. */
BE>ufs/dinode.h:	int32_t		di_atimensec;	/*  68: Last access time. */
BE>ufs/dinode.h:	int32_t		di_ctimensec;	/*  72: Last inode change time. */
BE>ufs/dinode.h:	int32_t		di_birthnsec;	/*  76: Inode creation time. */
BE>
BE>[Note that these aren't in a timespec struct, POSIX or otherwise, since the
BE>struct would give MD packing which happens to be inefficient in most cases.]
BE>
BE>ufs/dinode.h:	int32_t		di_atime;	/*  16: Last access time. */
BE>ufs/dinode.h:	int32_t		di_atimensec;	/*  20: Last access time. */
BE>ufs/dinode.h:	int32_t		di_mtime;	/*  24: Last modified time. */
BE>ufs/dinode.h:	int32_t		di_mtimensec;	/*  28: Last modified time. */
BE>ufs/dinode.h:	int32_t		di_ctime;	/*  32: Last inode change time. */
BE>ufs/dinode.h:	int32_t		di_ctimensec;	/*  36: Last inode change time. */
BE>
BE>[Y2.038K bugs are still in ffs1.]
BE>%%%
BE>
BE>To change time_t to 64 bits, all in-use non-transient data structures
BE>need to be changed similarly.

I guess we have to do this work before 2038, don't we? If we don't do it
before 5.2 we have to stick with this until 6.0. Correct?

harti
-- 
harti brandt,
http://www.fokus.fraunhofer.de/research/cc/cats/employees/hartmut.brandt/private
brandt at fokus.fraunhofer.de, harti at freebsd.org