On Thu, Jul 4, 2013 at 10:17 AM, Paul D. DeRocco <pdero...@ix.netcom.com> wrote: >> You don't need to copy it to somewhere else. You can replace an >> executable without the running process being disturbed, by deleting >> the file and creating (or moving) a new one in its place. Most tools >> (like "cp") will do this when they overwrite a file. Then simply >> restart the service (or have it exec() itself), and the new version >> will be running. >> >> The old version of the executable will continue to exist—even though >> it has no file name—until nothing uses it anymore. > > Is that true on all filesystems? This is a FAT16 volume on a flash drive in > an embedded system. It's also possible that the power might get yanked while > it's in this state, leaving an orphan file. Finally, since it will be > updated via a Samba file share, I don't know what sort of command will be > used to change it; it might be an overwrite plus lengthen or truncate > operation.
Yes, I believe it's true on all file systems. I tested again with FAT16. However, I was mistaken about "cp" doing a delete-and-replace by default, because I forgot I was using "cp --reflink=auto" on a btrfs volume. Without --reflink, I get an ETXTBSY when trying to copy over an in-use executable. "cp -f" works on both filesystems. Even if Samba doesn't cooperate, doing a manual delete before copying the new executable should work. _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
