for regular files. This fixes recent breakage of cp'ing from /dev/zero.
/dev/zero doesn't support mmap(), but the device driver mmap routines are
not called for mapping 0 bytes, so the error was not detected. mmap()
can't even be used for cp'ing special files that support mmap(), since
there is general way to determine the file size.
This should calm down attempts to `cp -p' to a nfs mount or some other
filesystem that doesn't accept flags or all combinations of flags.
It will warn if it fails to change flags though.
printed a bogus warning with a stale errno if write() returns a short
count. Now we continue copying. We still print a bogus warning if
write() returns an "impossible" short count of 0.
- Use MAP_FAILED instead of the constant -1 to indicate
failure (required by POSIX).
- Removed flag arguments of '0' (required by POSIX).
- Fixed code which expected an error return of 0.
- Fixed code which thought any address with the high bit set
was an error.
- Check for failure where no checks were present.
Discussed with: bde
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
documented and is incompatible with gnu cp. It has very few good effects
(it recovers some disk space) and many bad ones:
- special files are unlinked after certain errors.
- the data may not be recoverable if the source is a special file or fifo.
- unlinking destroys the target attributes as well as the target data.
- unlinking doesn't actually remove the target data if the target is multiply
linked.
