Provided by: clsync_0.4.3-1_amd64 bug

NAME

       clsync - live sync tool, written in GNU C

SYNOPSIS

       clsync [ ... ] -- [ sync-handler-arguments ]

DESCRIPTION

       clsync  executes  sync-handler  with  appropriate  arguments  on  FS  events  in directory
       watch-dir using the inotify(7) or other FS monitoring subsystems.

OPTIONS

       This options can be passed as arguments or to be used in the configuration file.

       To disable numeric option set to zero:
                   =0

       To disable string option (for example path to file) set to empty string:
                   =

       Also you can use previously set values while setting new options. Substring  %option_name%
       will  be  substituted with previously set value of option option_name.  (see CONFIGURATION
       FILE)

       sync-handler-arguments applies only to modes:
              simple, direct, shell, rsyncdirect, rsyncshell

       To set sync-handler-arguments in config file use '--'. An example:
              -- = -aH --exclude-from %EXCLUDE-LIST% --include-from=%INCLUDE-LIST% --exclude  '*'
              %watch-dir%/ %destination-dir%/

       -W, --watch-dir watch-dir
              Root directory to be monitored by clsync.

              Required.

       -S, --sync-handler sync-handler
              Path to sync-handler to be used for syncing by clsync.  (see --mode)

              Is  required  for  all  modes  except  "direct" and "rsyncdirect" [see SYNC HANDLER
              MODES]

       -R, --rules-file rules-file
              Path to file with filter rules of objects to be monitored. (see RULES)

              Is not set by default.

       -D, --destination-dir destination-directory
              Defines directory to sync to for modes  "rsyncdirect",  "rsyncso"  and  "so".  (see
              --mode)

              Is not set by default.

       -M, --mode mode
              Sets syncing mode. Possible values:
                     simple
                            calls sync-handler for every event
                     direct
                            calls  sync-handler  for  every  sync  with  passing  files  lists as
                            arguments
                     shell
                            calls sync-handler for every sync with passing files lists in a file
                     rsyncdirect
                            calls rsync by path sync-handler directly
                     rsyncshell
                            calls  sync-handler  that  supposed  to  run  rsync  for  every  sync
                            (recommended mode)"
                     rsyncso
                            loads  shared  object  by  path sync-handler with dlopen(3) and calls
                            function clsyncapi_rsync function for every sync
                     so
                            loads shared object by path sync-handler  with  dlopen(3)  and  calls
                            function clsyncapi_sync function for every sync

              See SYNC HANDLER MODES

              Required.

       -b, --background
              Daemonize, forcing clsync to fork() on start.

              Is not set by default.

       -H, --config-file config-file-path
              Use configuration from file config-file-path (see CONFIGURATION FILE).

              Set to "/NULL/" if no config files should be read.

              Is not set by default.

       -K, --config-block config-block-name
              Use configuration block with name config-block-name (see CONFIGURATION FILE).

              The default value is "default".

       --config-block-inherits config-parent-block-name
              Use   configuration   block   with  name  config-parent-block-name  as  parent  for
              config-block-name (see CONFIGURATION FILE).  Options from  config-parent-block-name
              will be inherited to config-block-name.

              The default value is "default".

       --custom-signals custom-signals
              Set  a  list of signals and corresponding config block names. The config block will
              be use on catching the corresponding signal.

              Format is
                     signal:config-block-name[,signal:config-block-name[,...]]

              For example:
                     --custom-signals=29:debug,28:normal
              In this line signals "28" and "29" will be added to  the  sighandler.   And  clsync
              will use options from config block "debug" on signal 29 and "normal" on signal 28.

              To reset all custom signals use the 0-th signal (e.g. "--custom-signals=0").

              The default value is "".

       -z, --pid-file path-to-pidfile
              Writes pid to file by path path-to-pidfile.

              Is not set by default.

       --status-file status-file-path
              Write status description into file with path status-file-path.

              Possible statuses:
                     starting
                            initializing  subsystems  and  marking  file  tree  with  FS  monitor
                            subsystem
                     initsync
                            processing initial syncing
                     running
                            waiting for events or syncing
                     synchandler error
                            waiting between synchandler execution tries  (after  a  failure)  [is
                            used only while --threading=off]
                     rehashing
                            reloading configuration files
                     thread gc
                            running threads' garbage collector
                     preexit
                            executing the --pre-exit-hook
                     terminating
                            running the last iteration (if required) and preparing to die
                     exiting
                            executing the --exit-hook and cleaning up [for valgrind(1)]

              Is not set by default.

       -r, --retries number-of-tries
              Tries limit to sync with sync-handler.

              clsync will die after number-of-tries tries.

              To try infinite set "0".

              Delay between tries is equal to --delay-sync value.

              The default value is "1".

       --ignore-failures
              Don't die on sync failures.

              Is not set by default.

       --exit-on-sync-skip
              Exit if some event could be skipped due to any reason.

              For  example  FreeBSD  has  a  very  short  BSM  event  queue  (1024). So it may be
              overflowed and some events can not climb to the queue. This option forces clsync to
              exit if the queue had been overflowed.

              Is not set by default.

       -p, --threading threading-mode
              [Not available on Debian/kFreeBSD]

              Use  pthreads(7)  to  parallelize  syncing  processes.  For example if clsync (with
              --threading=off) is already syncing a huge  file  then  all  other  syncs  will  be
              suspended  until the huge file syncing finish. To prevent this suspends you can use
              "safe" or "full" threading mode.

              Possbile values:
                     off
                            disable threading for syncing processes.
                     safe
                            parallelize syncs but suspend syncings of  object  that  are  already
                            syncing in another process (until the process finish).
                     full
                            parallelize syncs without suspendings.

              Characteristics:
                     off
                            New modifications won't be synced until old ones finish.
                     safe
                            Theoretically  is  the  best  way.  But  may utilize of lot of CPU if
                            there's a lot of simultaneous parallel syncs. (also this way  is  not
                            well tested)
                     full
                            May  cause  multiple  simultaneous syncing of the same file, which in
                            turn can cause bug inside sync-handler (see below).

              If you're running clsync with option --threading=full  in  conjunction  with  rsync
              with  option  --backup,  you  may  catch  a bug due to nonatomicity of rsync's file
              replace operation.  (see DIAGNOSTICS)

              The default value is "off".

       -Y, --output log-destination
              Sets destination for log writing (errors, warnings, infos and debugging).

              Possible values:
                     stderr
                     stdout
                     syslog

              The default value is "stderr".

       --one-file-system
              Don't follow to different devices' mount  points.  This  option  just  adds  option
              "FTS_XDEV" for fts_open(3) function.

              Warning!   If  you're using this option (but no --exclude-mount-points) clsync will
              write neither includes nor excludes of content of mount points.
              This may cause problems e.g. you're using rsync for  sync-handler  without  similar
              option "--one-file-system".

              Is not set by default.

       -X, --exclude-mount-points
              Forces --one-file-system but also add excludes to do not sync mount points.

              This requires to do stat(2) syscalls on every dir and can reduce performance.

              Is not set by default.

       --socket socket-path
              Create a control socket by path socket-path.

              This's very experimental feature.

              Is not set by default.

       --socket-own socket-owner-user[:socket-owner-group]
              Sets the control socket owner user (and group).

              Is not set by default

       --socket-mod socket-mode
              Sets the control socket mode [see chmod(2)].

              Is not set by default.

       --standby-file standby-file-path
              Sets file to path that should be checked before every sync. If file exists the sync
              will be suspended until the file is deleted. It may be useful if  you  need  freeze
              destination directory while running some scripts.

              Is not set by default.

       --max-iterations iterations-count
              Sets  synchronization  iterations  limit.  One  iteration  means  one  sync-handler
              execution.

              iterations-count
                     set to 0 means no limit (infinite loop).

                     set to 1 means that only initial sync will be done

                     set to n means that only initial sync and (n-1) sync-ups after that will  be
                     done

              Hint:  This option may be useful in conjunction with --exit-on-no-events to prevent
              infinite sync-up processes.

              The default value is "0".

       --modification-signature signature-mask
              Sets file/dir modification recheck signature. If file is not modified (according to
              the signature) then don't sync it.

              See struct stat in lstat(2) for possible fields.

              For         example         reasonable        signature-mask-s        can        be
              "dev,ino,mode,uid,gid,rdev,size,atime,mtime,ctime" (there's an  alias  for  that  —
              "*") or "uid,gid".

              Examples of use cases:
                     chown/chmod
                            If you're using clsync for fixing file/dir privileges [using chown(1)
                            and/or chmod(1)] than reasonable signature will be "uid,gid".

                            Full     example:     clsync     -w5     -t5     -T5      -x1      -W
                            /var/www/site.example.org/root  -Mdirect  -Schown  --uid  0  --gid  0
                            -Ysyslog  -b1   --modification-signature   uid,gid   --   --from=root
                            www-data:www-data %INCLUDE-LIST%
                     bi-directional syncing
                            If  you're  going  to  setup  bi-directional syncing then you may use
                            --modification-signature "*" to prevent sync loop between servers.
                     Not enough CPU
                            If rsync eats too many CPU with rechecking hashsums of files on their
                            dry  open()/close()  due  to some hacky script (for example "chown -R
                            www-data:www-data" in cron) then you can use --modification-signature
                            "dev,ino,mode,uid,gid,rdev,size,atime,mtime"    (without   "blksize",
                            "blocks", "nlink" and "ctime").

              Warning! This option may eat a lot of memory on huge file trees.

              This option cannot be used together with "--cancel-syscalls=mon_stat"

              To disable file/dir modification rechecking use empty value — "".

              The default value is "".

       -k, --timeout-sync sync-timeout
              Sets timeout for syncing processes.  clsync will die if syncing process alive  more
              than sync-timeout seconds.

              Set "0" to disable the timeout.

              The default value is "86400" ["24 hours"].

       -w, --delay-sync additional-delay
              Sets the minimal delay (in seconds) between syncs.

              The default value is "30".

       -t, --delay-collect ordinary-delay
              Sets the delay (in seconds) to collect events about ordinary files and directories.

              The default value is "30".

       -T, --delay-collect-bigfile bigfiles-delay
              Sets   the   delay   (in   seconds)  to  collect  events  about  "big  files"  (see
              --threshold-bigfile).

              The default value is "1800".

       -B, --threshold-bigfile filesize-threshold
              Sets file size threshold (in bytes) that separates ordinary files from "big files".
              Events  about "big files" are processed in another queue with a separate collecting
              delay. This is supposed to be used as a means of unloading IO resources.

              To disable detection of "big files" set "0" (zero). This can improve performance by
              removing necessity in extra lstat() syscall.

              The default value is "134217728" ["128 MiB"].

       --cancel-syscalls syscalls-mask
              Sets syscalls to be bypassed. This may be used for to squeeze more performance.

              Possible values:
                     mon_stat
                            Skip  lstat()  calls  while  handling  files/dirs  events. This makes
                            unpossible   to   determine   files   sizes   (that   is   used    by
                            --threshold-bigfile      option)      and      to      use     option
                            --modification-signature.

              You can combine this values using commas.

              To disable this option just use empty value — "".

              The default value is "".

       -L, --lists-dir tmpdir-path
              Sets directory path to output temporary events-lists files.

              See SYNC HANDLER MODES.

              Is not set by default.

       --have-recursive-sync
              Use action "recursivesync" instead of "synclist" for  directories  that  were  just
              marked (see SYNC HANDLER MODES case shell).

              Is not set by default.

       --synclist-simplify
              Removes the first 3 parameters in list files of action "synclist" (see SYNC HANDLER
              MODES case shell).

              Is not set by default.

       --rsync-inclimit rsync-includes-line-limit
              Sets soft limit for lines count in files by  path  rsync-listpath.   Unfortunately,
              rsync  works  very  slowly with huge "--include-from" files. So, clsync splits that
              list with approximately rsync-includes-line-limit lines per list if it's  too  big,
              and  executes  by  one  rsync  instance per list part. Use value "0" to disable the
              limit.

              The default value is "20000".

       --rsync-prefer-include
              Forces clsync to prefer a "lot of includes" method instead of a "excludes+includes"
              for rsync on recursive syncing.

              See cases rsyncshell, rsyncdirect and rsyncso of SYNC HANDLER MODES.

              This option is not recommended.

              Is not set by default.

       -x, --ignore-exitcode exitcode
              Forces  clsync to do not process exitcode exitcode of sync-handler as an error. You
              can set multiple ignores by passing this option multiple times.

              Recommended values for rsync case is "24". You can set multiple values with listing
              a lot of "-x" options (e.g. "-x 23 -x 24") or via commas (e.g. "-x 23,24"). To drop
              the list use zero exitcode (e.g. "-x 0"). For example you can use "-x 0,23" to drop
              the list and set "23"-th exitcode to be ignored.

              Is not set by default (or equally is set to "0").

       -U, --dont-unlink-lists
              Do not delete list-files after sync-handler has finished.

              This may be used for debugging purposes.

              Is not set by default.

       --fts-experimental-optimization
              Enable  experimental  features  to  optimize file tree scanning while using fts(3).
              The features will be enabled by default after appropriate testing.

              At the moment the option doesn't do anything but can be used in future.

              Is not set by default.

       -F, --full-initialsync
              Ignore filter rules from rules-file on initial sync.

              This may be useful for quick start or e.g. if it's  required  to  sync  "/var/log/"
              tree but not sync every change from there.

              Is not set by default.

       --only-initialsync
              Exit after initial syncing on clsync start.

              Is not set by default.

       --exit-on-no-events
              Exit  if  there's  no  events. Works like --only-initialsync, but also syncs events
              collected while the initial syncing.

              Unlike --only-initialsync this option uses FS monitor subsystem to monitor for  new
              events  while  the  initial syncing. This may reduce performance. On the other hand
              this way may be used to be sure, that everything is synced  at  the  moment  before
              clsync will exit.

              Is not set by default.

       --skip-initialsync
              Skip initial syncing on clsync start.

              Is not set by default.

       --exit-hook path-of-exit-hook-program
              Sets path of program to be executed on clsync exit.

              If this parameter is set then clsync will exec on exit:
                     path-of-exit-hook-program label

              The execution will be skipped if initial sync wasn't complete.

              Is not set by default.

       --pre-exit-hook path-of-pre-exit-hook-program
              Sets  path  of  program  to  be  executed  before  the  last  sync  iteration  (see
              --max-iterations, --exit-on-no-events and SIGNALS).

              If this parameter is set then clsync will exec on exit:
                     path-of-pre-exit-hook-program label

              The execution will be skipped if initial sync wasn't complete.

              If clsync finishes due to --exit-on-no-events and --pre-exit-hook is set  then  the
              pre-exit hook will be executed and additional sync iteration will be triggered.

              Is not set by default.

       -v, --verbose
              This  option  is  supposed  to  increase  verbosity.  But  at the moment there's no
              "verbose output" in the code, so the option does nothing. :)

              Is not set by default.

       -d, --debug
              Increases debugging output. This may be supplied multiple times for more  debugging
              information,  up to a maximum of five "d" flags (more will do nothing), for example
              "-d -d -d -d -d" or "-d5" (equivalent cases)

              Is not set by default.

       --dump-dir
              Directory to write clsync's instance information by signal 29 (see  SIGNALS).   The
              directory shouldn't exists before dumping.

              Is set to "/tmp/clsync-dump-%label%" by default.

       -q, --quiet
              Suppresses error messages.

              Is not set by default.

       --monitor monitor-subsystem
              Switches FS monitor subsystem.

              Possible values:
                     inotify
                            inotify(7) [Linux, (FreeBSD via libinotify)]

                            Native, fast, reliable and well tested Linux FS monitor subsystem.

                            There's  no  essential performance profit to use "inotify" instead of
                            "kevent" on FreeBSD  using  "libinotify".  It  backends  to  "kevent"
                            anyway.

                            FreeBSD  users:  The  libinotify  on  FreeBSD  is still not ready and
                            unusable for clsync to sync a lot of files and directories.

                     gio
                            Use gio library.

                            Crossplatform and tested library that backends to kqueue  on  FreeBSD
                            and  inotify  on  Linux.  See  inotify  and  kqueue sections here for
                            details.

                            Not well tested. Use with caution!

                     kqueue
                            kqueue(2) [FreeBSD, (Linux via libkqueue)]

                            A *BSD kernel event  notification  mechanism  (inc.  timer,  sockets,
                            files etc).

                            This  monitor  subsystem cannot determine file creation event, but it
                            can determine a directory where something happened. So clsync is have
                            to  rescan  whole  dir  every  time  on any content change. Moreover,
                            kqueue requires an open() on  every  watched  file/dir.  But  FreeBSD
                            doesn't  allow  one  to open() symlink itself (without following) and
                            it's highly invasively to open() pipes and devices.  So  clsync  just
                            won't call open() on everything except regular files and directories.
                            Consequently,  clsync  cannot  determine  if  something  changed   in
                            symlink/pipe/socket  and so on.  However it still can determine if it
                            will be created or deleted  by  watching  the  parent  directory  and
                            rescaning it on every appropriate event.

                            Also this API requires to open every monitored file and directory. So
                            it may produce a huge  amount  of  file  descriptors.  Be  sure  that
                            kern.maxfiles is big enough (in FreeBSD).

                            CPU/HDD expensive way.

                            Not well tested. Use with caution!

                            Linux users: The libkqueue on Linux is not working. He-he :)

                     bsm
                            bsm(3) [FreeBSD]

                            Basic Security Module (BSM) Audit API.

                            This  is  not  a  FS monitor subsystem, actually. It's just an API to
                            access to audit information (inc. logs).  clsync can setup  audit  to
                            watch  FS  events and report it into log. After that clsync will just
                            parse the log via auditpipe(4) [FreeBSD].

                            Reliable, but hacky way. It  requires  global  audit  reconfiguration
                            that may hopple audit analysis.

                            Warning!   FreeBSD  has a limit for queued events. In default FreeBSD
                            kernel it's only 1024 events. So choose one of:
                                   - To patch the kernel to increase the limit.
                                   - Don't use clsync on systems with too many file events.
                                   - Use bsm_prefetch mode (but there's no guarantee in this case
                                   anyway).
                            See also option --exit-on-sync-skip.

                            Not     well     tested.     Use    with    caution!     Also    file
                            /etc/security/audit_control will be overwritten with:
                                   #clsync

                                   dir:/var/audit
                                   flags:fc,fd,fw,fm,cl
                                   minfree:0
                                   naflags:fc,fd,fw,fm,cl
                                   policy:cnt
                                   filesz:1M
                            unless it's already starts with  "#clsync\n"  ("\n"  is  a  new  line
                            character).

                     bsm_prefetch
                            The  same  as  bsm  but  all  BSM  events  will  be  prefetched by an
                            additional thread to prevent BSM queue overflow. This may  utilize  a
                            lot of memory on systems with a high FS events frequency.

                            However  the  thread  may be not fast enough to unload the kernel BSM
                            queue. So it may overflow anyway.

              The default value on Linux is "inotify". The default value on FreeBSD is "kqueue".

       -l, --label label
              Sets a label for this instance of clsync. The label will be passed to  sync-handler
              every execution.

              The default value is "nolabel".

       -h, --help
              Outputs options list and exits with exitcode "0".

              Is not set by default.

       -V, --version
              Outputs clsync version and exits with exitcode "0".

              Is not set by default.

       --cgroup-group-name cg-group-name
              Set cgroup group name [see cgroup_new_cgroup()].

              Is set to "clsync/%PID%" by default.

SECURITY OPTIONS

       --secure-splitting
              Implies      "--splitting=process     --check-execvp-arguments     --seccomp-filter
              --forbid-devices"

       -u, --uid uid
              Drop user privileges to uid uid with setuid(2)

              If there's a capabilities(7) support then the default value is "nobody" (or "65534"
              if "nobody" not found), otherwise the option is not set by default;

       -g, --gid gid
              Drop group privileges to gid gid with setgid(2)

              If  there's  a  capabilities(7)  support  then  the  default value is "nogroup" (or
              "65534" if "nogroup" not found), otherwise the option is not set by default;

       --privileged-uid sync-handler-uid
              An user ID to be used for the privileged process (see --splitting=process).

              The default value is "$UID".

       --privileged-gid sync-handler-gid
              A group ID to be used for the privileged process (see --splitting=process).

              The default value is "$GID".

       --sync-handler-uid sync-handler-uid
              An user ID to be used for sync-handler.

              See --preserve-capabilities.

              The default value is same as for --privileged-uid.

       --sync-handler-gid sync-handler-gid
              A group ID to be used for sync-handler.

              See --preserve-capabilities.

              The default value is same as for --privileged-gid.

       -C, --preserve-capabilities capabilities-list
              [Linux only, requires capabilities]

              Use capset(2) and prctl(2) to preserve "CAP_DAC_READ_SEARCH",  "CAP_SETUID"  or/and
              "CAP_SETGID"  [see  capabilities(7)]  Linux  capability  for  process using fts(3),
              inotify(7) and execve(2).  This allows the preservation of enough FS privileges  to
              watch  a  file  tree  and  execute  the sync-handler with required uid and gid [see
              --sync-handler-uid and --sync-handler-gid] after dropping privileges via  setuid(2)
              and setgid(2) [see --uid and --gid]

              Possible values:
                     CAP_DAC_READ_SEARCH
                            To bypass FS read checks (for fts and inotify).
                     CAP_SETUID
                            To be able to use setuid(2) before execve(2) on the sync-handler.
                     CAP_SETGID
                            To be able to use setgid(2) before execve(2) on the sync-handler.
                     CAP_KILL
                            To be able to kill setuid()-ed processes

                     Any  combinations  of  this  values  are  also  supported.  The  list may be
                     presented as a comma separated values, like:
                            CAP_DAC_READ_SEARCH,CAP_SETUID,CAP_SETGID

              The default value is  "CAP_DAC_READ_SEARCH,CAP_SETUID,CAP_SETGID,CAP_KILL"  if  the
              clsync runner have such privileges.

       --inherit-capabilities
              [Linux only, requires capabilities]

              Sets a mode for capabilities inheriting.

              Possible values:
                     permitted
                            Inherits all permitted capabilities
                     dont-touch
                            Don't change inheritable capabilities set
                     clsync
                            Use clsync's effective capabilities set
                     empty
                            Reset all capabilities

              The default value is "empty".

       --splitting splitting-type
              Split the process/thread to privileged and non-privileged. This's an additional way
              to secure your system from any bug in clsync while running it with capabilities  or
              root  privileges. But clsync may utilize in few times more CPU resources. So it's a
              performance vs security trade off.

              You  can  essentialy  reduce  the   overhead   with   using   "high   load   locks"
              ("--enable-highload-locks" of "./configure" file).

              If  you're  using  this option and running the sync-handler with the root user then
              it's highly recommended to enable --check-execvp-arguments, too. Otherwise in  case
              of  clsync  security  bug  a hacker will be able to use execvp() with any arguments
              with root privileges.

              Possible values:
                     off
                            Disable this feature
                     thread
                            [Linux only, requires capabilities]

                            Creates a separate thread for privileged operations.

                            It's highly recommended to enable --seccomp-filter in this case.  But
                            that will forbid --threading.
                     process
                            More secure and portable way, but uses separate process and:
                                   - forbids fanotify (that is not implemented yet anyway);
                                   - more complex code (and higher probability of error).
                                   - slower due to copying data between private and shared memory
                                   pages.

                            Recommended.

              Is set to "off" by default.

       --check-execvp-arguments
              [Requires --splitting=[thread|process]]
              [Blocks --mode=direct]

              Enables execvp() arguments recheck in the privileged  process  (in  case  of  their
              substitution to any exploit-given arguments).

              This option doesn't utilize a lot of CPU resources but forbids run-time changing of
              sync-handler-arguments and hook file paths.

              This option cannot be used in conjunction with --mode=direct due  to  an  arbitrary
              number of arguments in this mode.

              Is not set by default.

       --add-permitted-hook-files [hook-path0,[hook-path1[,...]]]
              [Requires --check-execvp-arguments]

              Adds  paths  to the list of permitted hook paths to bypass --check-execvp-arguments
              checks. It may be required if you're going to change the hooks  in  run-time  using
              --custom-signals or --socket.

              Is not set by default.

       --seccomp-filter
              [Linux only]

              Use seccomp filter to forbid syscalls that shouldn't be used by clsync.

              Forbid all syscalls for non-privileged process/thread, but
                     futex  inotify_init1  alert  stat  fstat lstat open write close wait4 unlink
                     tgkill clock_gettime rt_sigreturn brk mmap  munmap  wait4  rmdir  exit_group
                     select read rt_sigprocmask rt_sigaction nanosleep

              Is not set by default.

       --permit-mprotect
              [Requires --seccomp-filter]

              Permits mprotect(2) syscall.

              This syscall is required by pthread_create(3), so it's required for --threading.

              Makes --shm-mprotect to be useless.

              Also  it enables ability to change memory of privileged thread from non-privileged,
              so using of --splitting=thread with this option is useless, too.

              Is set to "0" by default if --splitting is set. Otherwise "1".

       --shm-mprotect
              [Requires --splitting=process]

              Forbid writing or reading to/from shared memory when it shouldn't be.   mprotect(2)
              is used for the protection.

              This option is useless while --permit-mprotect is enabled.

       --chroot chroot-directory
              clsync  chroot()-s [see chroot(2)] to directory chroot-directory before any syncing
              processes.

              This option may be used in conjunction with --uid, --gid  or/and  --pivot-root  for
              security reasons.

              Remember! If you're chroot()-ing somewhere, the sync-handler will be limited by the
              chroot-environment, too. If you're using rsync then you may want to "mount  --bind"
              some directories to the chroot-directory.

              Is not set by default.

       --pivot-root pivot-root-way
              [Linux only, requires --chroot]

              Sets a way of using pivot_root(2) syscall to the chroot-directory (to umount(2) old
              rootfs).

              Possible values:
                     auto
                            Creates  a  directory  "/dev/shm/clsync-rootfs",  unshare(2)-ing  the
                            mount namespace, mount(2)-s the chroot-directory to the directory and
                            then pivot_root(2)-ing, chroot(2)-ing and umount(2)-ing  old  rootfs.
                            Directory  "/dev/shm/clsync-rootfs"  won't  be  deleted  after clsync
                            finish.
                     auto-ro
                            The same as auto but  mounts  the  directory  with  read-only  option
                            (MS_RDONLY).
                     direct
                            unshare(2)-ing  the mount namespace, pivot_root(2)-ing, chroot(2)-ing
                            and umount(2)-ing old rootfs. Directory "old_root" should be  created
                            in chroot-directory before running clsync in this mode.
                     off
                            Don't pivot_root(2).

              The  default  value  is  "off".  If  --chroot  is  used  then  recommended value is
              "auto-ro".

       --mountpoints [mountpoint[,mountpoint[,mountpoint]]]
              [Linux only]

              Umount (with MNT_DETACH) everything except listed mountpoints.

              Supposed to be used for security reasons as an alternative to --pivot-root option.

              Is not set by default.

       --detach-network detach-network-mode
              [Linux only]

              Removes network in clsync instance.

              Possible values:
                     everywhere
                            Removes network for all processes.
                     non-privileged
                            Removes   network   from    non-privileged    process    if    option
                            --process-splitting is enabled, otherwise doesn't do anything.
                     off
                            Don't do anything.

              The default value is "non-privileged".

       --detach-ipc
              [Linux only]

              Make an own IPC namespace.

              Is set by default.

       --detach-miscellanea
              [Linux only]

              unshare(2) on everything not listed above.

              Is not set by default.

       --forbid-devices
              [Linux only]

              Forbid any access to all devices except listed ones:
                     read access to:
                            /dev/console
                            /dev/zero
                            /dev/urandom
                            /dev/random
                     write access to:
                            /dev/console
                            /dev/null

              Is not set by default.

PERFORMANCE

       Recommendations to improve the performance:
              - Disable thread/process splitting.
              -  Don't  use  clsync  rules  (use  rules  on  sync-handler side) or/and use option
              "--full-initialsync"
              - Use option "-B0".
              - Use option "--cancel-syscalls=mon_stat".
              - Use option "-p safe" or "-p full".
              - Disable debugging with "-d0" or better disable  debugging  support  at  all  with
              "./configure" option "--enable-debug=no"
              - Don't use option "--exclude-mount-points"
              - Free memory for disk cache

       You shouldn't follow all this recommendation blindfold. You should use only the ideas that
       fixes performance problems in your specific use case. And only if it's necessary.

SYNC HANDLER MODES

       clsync executes sync-handler that supposed to take care of  the  actual  syncing  process.
       Therefore clsync is only a convenient way to run a syncing script.

       clsync  can  run  sync-handler  in seven ways. Which way will be used depends on specified
       mode (see --mode)

       sync-handler-arguments are used only in modes:
              simple
              direct
              shell
              rsyncdirect
              rsyncshell

       If sync-handler-arguments are not set then the default setting is used (see below).

       case simple
              Executes for every syncing file/dir:
                     sync-handler sync-handler-arguments

              Default sync-handler-arguments are:
                     sync %label% %EVENT-MASK% %INCLUDE-LIST%

              In this case, sync-handler is supposed to non-recursively sync file or directory by
              path %INCLUDE-LIST%.  With %EVENT-MASK% it's passed bitmask of events with the file
              or directory (see "/usr/include/linux/inotify.h").

              Additional substitutions:
                     %EVENT-MASK%
                            Is replaced by integer of events IDs.
                     %INCLUDE-LIST%
                            Is replaced by absolute path of a file/dir to be synced.

       case direct
              Executes for every sync:
                     sync-handler sync-handler-arguments

              Default sync-handler-arguments are:
                     %INCLUDE-LIST% %destination-dir%/

              Additional substitutions:
                     %INCLUDE-LIST%
                            Is replaced by a list of relative paths of files/dirs to be synced.

       case shell
              Executes for every sync (if recursivesync is not used instead):
                     sync-handler sync-handler-arguments

              Default sync-handler-arguments are:
                     synclist %label% %INCLUDE-LIST-PATH%

              Default sync-handler-arguments for initial sync  if  --have-recursive-sync  is  set
              are:
                     initialsync %label% %INCLUDE-LIST%

              In   this  case,  sync-handler  is  supposed  to  non-recursively  sync  files  and
              directories from list in a file by path %INCLUDE-LIST-PATH% on "synclist".

              Also sync-handler is supposed to recursively  sync  data  from  directory  by  path
              %INCLUDE-LIST-PATH% with manual excluding extra files on "initialsync".

              Additional substitutions:
                     %TYPE%
                            Is replaced by "sync"/"initialsync".
                     %INCLUDE-LIST-PATH%
                            Is replaced by the path of the include list file.
                     %INCLUDE-LIST%
                            Is replaced by a list of relative paths of files/dirs to be synced.

              Not recommended. Not well tested.

       case rsyncdirect
              Executes for every sync:
                     sync-handler sync-handler-arguments

              sync-handler is supposed to be a path to rsync binary.

              Default sync-handler-arguments are:
                     -aH     --delete     --exclude-from    %EXCLUDE-LIST-PATH%    --include-from
                     %INCLUDE-LIST-PATH% --exclude='*' %watch-dir%/ %destination-dir%/
              if option --rsync--prefer-include is not set and
                     -aH --delete --include-from %INCLUDE-LIST-PATH%  --exclude='*'  %watch-dir%/
                     %destination-dir%/
              if the option is set

              Error  code  "24" from sync-handler will be ignored in this case. We also recommend
              to ignore exitcode "23".

              Additional substitutions:
                     %INCLUDE-LIST-PATH%
                            Is replaced by the path of the include list file
                     %EXCLUDE-LIST-PATH%
                            Is replaced by the path of the exclude list file
                     %RSYNC-ARGS%
                            Is  replaced   by   default   sync-handler-arguments,   but   without
                            "%watch-dir%/ %destination-dir%/"

              Recommended case.

       case rsyncshell
              Executes for every sync:
                     sync-handler sync-handler-arguments

              Default sync-handler-arguments are:
                     rsynclist %label% %INCLUDE-LIST-PATH% [%EXCLUDE-LIST-PATH%]

              In this case, sync-handler is supposed to run "rsync" application with parameters:

              -aH --delete-before --include-from %INCLUDE-LIST-PATH% --exclude '*'

              if option --rsync-prefer-include is enabled.

              And with parameters:

              -aH     --delete-before     --exclude-from    %EXCLUDE-LIST-PATH%    --include-from
              %INCLUDE-LIST-PATH% --exclude '*'

              if option --rsync-prefer-include is disabled.

              Additional substitutions:
                     %INCLUDE-LIST-PATH%
                            Is replaced by the path of the rsync include list file
                     %EXCLUDE-LIST-PATH%
                            Is replaced by the path of the rsync exclude list file

              Recommended case.

       case rsyncso
              In this case there's no direct exec*() calling. In this  case  clsync  loads  sync-
              handler   as   a   shared   library   with   dlopen(3)   and  calls  function  "int
              clsyncapi_rsync(const char *inclist, const char *exclist)" from it for every sync.
              inclist is a path to file with rules for "--include-from" option  of  rsync.   This
              argument is always not NULL.
              exclist  is  a  path to file with rules for "--exclude-from" option of rsync.  This
              argument is NULL if --rsync-prefer-include is set.
              Excludes takes precedence over includes.

              Also may be defined functions "int clsyncapi_init(ctx_t *, indexes_t *)"  and  "int
              clsyncapi_deinit()"  to  initialize  and  deinitialize  the syncing process by this
              shared object.

              To fork the process should be used function "pid_t clsyncapi_fork(ctx_t *)" instead
              of "pid_t fork()" to make clsync be able to kill the child.

              See example file "clsync-synchandler-rsyncso.c".

              Recommended case.

       case so
              In  this  case  there's  no direct exec*() calling. In this case clsync loads sync-
              handler  as  a  shared   library   with   dlopen(3)   and   calls   function   "int
              clsyncapi_sync(int n, api_eventinfo_t *ei)" from it for every sync.  n is number of
              elements of ei.  ei is an array of structures with information about what  and  how
              to sync (see below).

              api_eventinfo_t is a structure:
                     struct api_eventinfo {
                             uint32_t          evmask;        //  event  bitmask  for file/dir by
                     path path.
                             uint32_t          flags;         //  flags  of  "how  to  sync"  the
                     file/dir
                             size_t           path_len;      // strlen(path)
                             const  char       *path;          // the path to file/dir need to be
                     synced
                             eventobjtype_t   objtype_old;   //  type  of  object  by  path  path
                     before the event.
                             eventobjtype_t   objtype_new;   // type of object by path path after
                     the event.
                     };
                     typedef struct api_eventinfo api_eventinfo_t;

              The    event    bitmask     (evmask)     values     can     be     learned     from
              "/usr/include/linux/inotify.h".

              There may be next flags' values (flags):
                     enum eventinfo_flags {
                             EVIF_NONE        = 0x00000000,  // No modifier
                             EVIF_RECURSIVELY = 0x00000001   // sync the file/dir recursively
                     };
              Flag "EVIF_RECURSIVELY" may be used if option --have-recursive-sync is set.

              Is  that  a  file  or directory by path path can be determined with objtype_old and
              objtype_new.
              objtype_old reports about which type was the object by the path before the event.
              objtype_new reports about which type became the object by the path after the event.

              objtype_old and objtype_new have type eventobjtype_t.

                     enum eventobjtype {
                             EOT_UNKNOWN     = 0,  // Unknown
                             EOT_DOESNTEXIST = 1,  // Doesn't exist (not created yet  or  already
                     deleted)
                             EOT_FILE        = 2,  // File
                             EOT_DIR         = 3,  // Directory
                     } typedef enum eventobjtype eventobjtype_t;

              Also  may  be  defined functions "int clsyncapi_init(options_t *, indexes_t *)" and
              "int clsyncapi_deinit()" to initialize and deinitialize the syncing process by this
              shared object.

              To  fork  the  process  should be used function "pid_t clsyncapi_fork(options_t *)"
              instead of "pid_t fork()" to make clsync be able to kill the child.

              See example file "clsync-synchandler-so.c".

              Recommended case.

ENVIRONMENT VARIABLES

       Output variables - variables that are set by clsync before calling sync-handler.

       Output variables
              CLSYNC_STATUS  -  clsync's  status  (see  possible  statuses  in   description   of
              --status-file)

              CLSYNC_ITERATION  -  count of done synchronizaton iterations after initial sync see
              --max-iterations option

RULES

       Filter rules can be used to set which events clsync should monitor  and  which  events  it
       should ignore.

       Caution!   This  rules  doesn't guarantee that filtered file/dir won't be synced. This can
       occur because file or directory can appear in the moment of sync-handler running (or after
       it  but  before the sync-handler will reach the directory), so it'll be too late to add an
       exclusion. If you need a guarantee of file syncing preventing you can use internal  filter
       rules   of   the  sync-handler  program  (for  example,  rsync  has  options  "--exclude",
       "--exclude-from" and "--filter") or use disable  any  "recursive"  syncs  in  clsync  (and
       remove "-av" option of rsync if it's used). To disable recursive syncs you can use:
              simple
                     Already non-recursive
              direct
                     Already non-recursive
              shell
                     Don't enable option --have-recursive-sync.
              rsyncdirect
                     Use  option --rsync-prefer-include and set sync-handler-arguments to -lptgoD
                     --delete  --include-from  %INCLUDE-LIST-PATH%   --exclude='*'   %watch-dir%/
                     %destination-dir%/
              rsyncshell
                     Use option --rsync-prefer-include.
              rsyncso
                     Use option --rsync-prefer-include.
              so
                     Don't enable option --have-recursive-sync.

       Filter rules can be placed into rules-file with one rule per line.

       Rule format: [+-][fdWwms*]regexp

              + - means include;
              - - means exclude;
              f - means file;
              d - means directory (the same as an combination of "w" + "m" + "s");
              w - means walking to directory;
              m - means monitor events in the directory;
              s - means sync the the directory if modified;
              W - means walk + monitor the directory (the same as an combination of "w" + "m");
              * - means all.

       For example: -*^/[Tt]est

       It's  not  recommended  to use w rules in modes "rsyncdirect", "rsyncshell" and "rsyncso".
       rsync(1) allows one to  set  syncing  and  walking  only  together  in  "--include"  rules
       ("--files-from"  is not appropriate due to problem with syncing files deletions). So there
       may be problems with clsync's w rules in this cases.

       More examples:

       Syncing pwdb files and sshd_config (non-rsync case):
                   # which files to sync:
                   +f^passwd$
                   +f^group$
                   +f^shadow$
                   +f^ssh/sshd_config$

                   # walk and monitor next directories:
                   +W^$
                   +W^ssh$

                   # forbid the rest:
                   -*

       Syncing pwdb files and sshd_config (rsync case):
                   +f^passwd$
                   +f^group$
                   +f^shadow$
                   +f^ssh/sshd_config$
                   +d^$
                   +d^ssh$
                   -*

       Syncing /srv/lxc tree (rsync case):
                   -d/sess(ion)?s?$
                   -f/tmp/
                   +*

SIGNALS

       1  - (HUP) rereads filter rules

       2  - (INT) exits without waiting of syncing processes ("hard kill", kills children)

       3  - (QUIT) waits for current syncing processes and exit ("soft kill", waits for children)

       10 - runs threads' GC function

       12 - runs full resync

       15 - (TERM) exits without waiting of syncing processes ("hard kill", kills children)

       16 - interrupts sleep()/select() and wait() [for debugging and internal uses]

       29 - dump information to dump-dir [for debugging]

       If you need to kill clsync but leave children then you can use 9-th (KILL) signal.

DIAGNOSTICS

       clsync misses events:
              Try to run command: sysctl fs.inotify.max_queued_events=1048576

       Initial rsync process works very slow on clsync start
              Probably there's too huge exclude list is passed to rsync.  This  can  happened  if
              you're  excluding with regex in clsync's rules a lot of thousands files.  They will
              be passed to rsync's exclude list one by one.

              To diagnose it, you can use "-U" option and look into  rsync-exclude-listpath  file
              (see SYNC HANDLER case d)

              To  prevent  this, it's recommended to write such rules for rsync directly (not via
              clsync).

              For example, often problem is with PHP's session files. You shouldn't exclude  them
              in  clsync's  rules  with "-f/sess_.*", but you should exclude it in rsync directly
              (e.g with «--exclude "sess_*"»).

       The following diagnostics may be issued on stderr:

       Error: Cannot inotify_add_watch() on [...]: No space left on device (errno: 28)
              Not enough inotify watching descriptors is allowed. It can be fixed  by  increasing
              value of "sysctl fs.inotify.max_user_watches"

       Error: Got non-zero exitcode exitcode [...]
              sync-handler  returned non-zero exitcode. Probably, you should process exitcodes in
              it or your syncer process didn't worked well. I case of using rsync, you  can  find
              the exitcodes meanings in man 1 rsync.

              If  exitcode  equals  to 23 and you're using clsync in conjunction with rsync, this
              may happen, for example, in the following cases:

                     - Not enough space on destination.

                     - You're running clsync with --threading=full and rsync with --backup.  See
                     a bugreport ⟨https://bugzilla.samba.org/show_bug.cgi?id=10081⟩.

              To  confirm  the  problem,  you  can  try  to  add "return 0" or "exit 0" into your
              sync-handler.

       Bad system call
              If --use-seccomp option is enabled then the error is probably caused  by  using  of
              forbidden syscall. It's a clsync bug or hack attack attempt.

       To get support see SUPPORT.

CONFIGURATION FILE

       clsync supports configuration file.

       By default clsync tries to read next files (in specified order):
              ~/.clsync.conf
              /etc/clsync/clsync.conf

       This may be overridden with option --config-file.

       clsync  reads  only one configuration file. In other words, if option --config-file is not
       set and file ~/.clsync.conf is accessible and  parsable,  clsync  will  not  try  to  open
       /etc/clsync/clsync.conf.  Command line options have precedence over config file options.

       Configuration  file is parsed with glib's g_key_file_* API. That means, that config should
       consits from groups (blocks) of key-value lines as in the example:
              [default]
              background = 1
              mode = rsyncshell
              debug = 0
              output = syslog
              label = default
              pid-file = /var/run/clsync-%label%.pid

              [debug]
              config-block-inherits = default
              debug = 5
              background = 0
              output = stderr

              [test]
              mode=rsyncdirect
              debug=3

       Also glib's gkf API doesn't support multiple assignments. If you need to list some  values
       (e.g.   exitcodes)   just   list   them   with   commas   in   single   assignment   (e.g.
       "ignore-exitcode=23,24").

       In this example there're 3 blocks are set - "default",  "debug"  and  "test".   And  block
       "debug"  inherited  setup  of  block  "default"  except  options "debug", "background" and
       "output".

       By default clsync uses block with  name  "default".  Block  name  can  be  set  by  option
       --config-block.

CLUSTERING

       Not implemented yet.  Don't try to use cluster functionality.

       Not described yet.

EXAMPLES

       Mirroring a directory:
              clsync -Mrsyncdirect -W/path/to/source_dir -D/path/to/destination_dir

       Syncing 'authorized_keys' files:
              mkdir -p /etc/clsync/rules
              printf    "+w^$\n+w^[^/]+$\n+W^[^/]+/.ssh$\n+f^[^/]+/.ssh/authorized_keys$\n-*"   >
              /etc/clsync/rules/authorized_files_only
              clsync         -Mdirect          -Scp          -W/mnt/master/home/          -D/home
              -R/etc/clsync/rules/authorized_files_only    --   -Pfp   --parents   %INCLUDE-LIST%
              %destination-dir%

       Mirroring a directory, but faster:
              clsync -w5 -t5 -T5 -Mrsyncdirect -W/path/to/source_dir -D/path/to/destination_dir

       Instant mirroring of a directory:
              clsync -w0 -t0 -T0 -Mrsyncdirect -W/path/to/source_dir -D/path/to/destination_dir

       Making two directories synchronous:
              clsync  -Mrsyncdirect  --background   -z   /var/run/clsync0.pid   --output   syslog
              -Mrsyncdirect -W/path/to/dir1 -D/path/to/dir2 --modification-signature '*'
              clsync   -Mrsyncdirect   --background   -z   /var/run/clsync1.pid  --output  syslog
              -Mrsyncdirect -W/path/to/dir2 -D/path/to/dir1 --modification-signature '*'

       Fixing privileges of a web-site:
              clsync -w3 -t3 -T3 -x1 -W/var/www/site.example.org/root -Mdirect  -Schown  --uid  0
              --gid    0   -Ysyslog   -b1   --modification-signature   uid,gid   --   --from=root
              www-data:www-data %INCLUDE-LIST%

       'Atomic' sync:
              clsync --exit-on-no-events  --max-iterations=20  --mode=rsyncdirect  -W/var/www_new
              -Srsync -- %RSYNC-ARGS% /var/www_new/ /var/www/

       Moving a web-server:
              clsync  --exit-on-no-events  --max-iterations=20 --pre-exit-hook=/root/stop-here.sh
              --exit-hook=/root/start-there.sh     --mode=rsyncdirect     --ignore-exitcode=23,24
              --retries=3  -W /var/www -S rsync -- %RSYNC-ARGS% /var/www/ rsync://clsync@another-
              host/var/www/

       Copying files to slave-nodes using pdcp(1):
              clsync  -Msimple  -S  pdcp  -W  /opt/global  -b  -Y  syslog  --  -a  %INCLUDE-LIST%
              %INCLUDE-LIST%

       Copying files to slave-nodes using uftp(1):
              clsync   -Mdirect  -S  uftp  -W/opt/global  --background=1  --output=syslog  --  -M
              248.225.233.1 %INCLUDE-LIST%

       A dry running to see rsync(1) arguments that clsync will use:
              clsync -Mrsyncdirect -S echo -W/path/to/source_dir -D/path/to/destination_dir

       An another dry running to look how clsync will call pdcp(1):
              clsync -Msimple -S echo -W /opt/global -b0 -- pdcp -a %INCLUDE-LIST% %INCLUDE-LIST%

       Automatically run 'make build' if any '*.c' file changed
              printf "%s\n" "+f.c$" "-f"  |  clsync  --have-recursive-sync  -W  .  -R  /dev/stdin
              -Mdirect -r1 --ignore-failures -t1 -w1 -Smake -- build

       More working examples you can try out in "/usr/share/doc/clsync/examples/" directory. Copy
       this directory somewhere (e.g. into "/tmp"). And try  to  run  "clsync-start-rsync.sh"  in
       there.   Any   files/directories   modifications  in  "testdir/from"  will  be  synced  to
       "testdir/to" in a few seconds.

AUTHOR

       Dmitry Yu Okunev <dyokunev@ut.mephi.ru> 0x8E30679C

SUPPORT

       You can get support on official IRC-channel in Freenode "#clsync"  or  on  github's  issue
       tracking system of the clsync repository ⟨https://github.com/xaionaro/clsync⟩.

       Don't be afraid to ask about clsync configuration, ;).

SEE ALSO

       rsync(1), pthreads(7), inotify(7) kqueue(2)