bug#61386: [PATCH] cp,mv,install: Disable sparse copy on macOS

[Paul Eggert]

George, given what you've written I suppose we should give up the idea 
of copying sparse files efficiently on macOS (and on FreeBSD 
13.0-RELEASE, as it has a similar bug with SEEK_HOLE and SEEK_DATA), in 
cases where fclonefileat does not work.

Please try the attached Gnulib patch; it uses your idea of disabling 
SEEK_HOLE and SEEK_DATA on macOS, except on steroids because it disables 
these two macros everywhere, for all Gnulib-using applications, and it 
also disables them on FreeBSD < 14. For coreutils you need only this 
patch's change to lib/unistd.in.h. If this works for you I suppose we 
can install it into Gnulib and propagate that into coreutils etc.

Also, you reported the bug against macOS 12.6. Can you check whether the 
same bug occurs on macOS 13? If it's still there I suppose the attached 
patch will need to be updated since it guesses the bug is fixed in macOS 13.

I'll cc this email to bug-gnulib to give them a heads-up. (Gnulib 
readers can see <https://bugs.gnu.org/61386> for context.)

Really, Apple should fix this serious data corruption bug in APFS and macOS.

0001-lseek-avoid-SEEK_HOLE-bugs-in-FreeBSD-macOS.patch
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