feat: lock backups internally so cron needs no flock wrapper

rsyncshot now acquires an exclusive, non-blocking lock (fd 200) before the backup phase, so a slow backup can't overlap the next cron tick. Only real backups lock. Help, list, status, and dryrun don't, so they're never blocked.

The lock file defaults to /run/lock/rsyncshot.lock, a root-only directory that avoids the symlink-truncation risk of a predictable name in world-writable /tmp. It falls back to /var/lock then /tmp, and is configurable via LOCKFILE. It's deliberately a different file from the old /tmp/rsyncshot.lock cron wrappers, so existing wrapped crontabs keep working until the wrapper is removed.

setup() no longer wraps cron entries in flock, since the script locks itself.

0 files changed, 0 insertions, 0 deletions