RE: cp -p : timestamp NOT preserved (coreutils 6.9, Linux)

[Philip Rowlands]

On Wed, 31 Oct 2007, Graf, Peter wrote:

> Additional info to my former mail:
>
> 1) My former mail contained a small inconsistency (after anonymizing the user 
> name).  The following messages   show the problem in a consistent way 
> (username, home-directory name):
>
> ...
> prompt%  cp -p ~/.cshrc ~/tmp/.cshrc
> prompt%  ls -l ~/.cshrc ~/tmp/.cshrc
> -rwxr-x--- 1 pg mygroup 2180 Jan 19  2007 /home/pg/.cshrc
> -rwxr-x--- 1 pg mygroup 2180 Oct 31 14:46 /home/pg/tmp/.cshrc
> Timestamp was NOT preserved.

Does strace show the cause of the problem?

$ strace -e trace=file cp --preserve=timestamps a b
on my system gives:

[ snipped ld.so stuff ]
stat64("b", 0xffffd7f0)                 = -1 ENOENT (No such file or directory)
stat64("a", {st_mode=S_IFREG|0640, st_size=0, ...}) = 0
stat64("b", 0xffffd63c)                 = -1 ENOENT (No such file or directory)
open("a", O_RDONLY|O_LARGEFILE)         = 3
open("b", O_WRONLY|O_CREAT|O_LARGEFILE, 0100640) = 5
utimes("/proc/self/fd/5", {1193849440, 0}) = 0

"utimes" is the relevent system call, which sets the timestamps on the 
inode.


Cheers,
Phil