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distccd(1)                                                          distccd(1)




NAME

       distccd - distributed C/C++ compiler server


SYNOPSIS

       distccd --daemon [OPTIONS]


DESCRIPTION

       distccd  is  the  server  for  the  distcc(1) distributed compiler.  It
       accepts and runs compilation jobs for network clients.

       distcc can run over either TCP or a connection command such as  ssh(1).
       TCP  connections are fast but relatively insecure.  SSH connections are
       secure but slower.

       For SSH connections, distccd must be installed  on  the  volunteer  but
       should  not  run  as a daemon -- it will be started over SSH as needed.
       SSH connections have several advantages: neither the client nor  server
       listens  on  any new ports; compilations run with the privileges of the
       user that requested them; unauthorized users cannot access the  server;
       and source and output is protected in transit.

       For  TCP  connections,  distccd can run either from an inetd-style pro-
       gram, or as  a  standalone  server.   Standalone  mode  is  recommended
       because  it  is  slightly more efficient and allows distccd to regulate
       the number of incoming jobs.  The --listen and --allow options  can  be
       used for simple IP-based access control.

       distcc  may  be  started  either  by root or any other user.  If run by
       root, it gives away privileges and changes to the user specified by the
       --user  option,  or  the  user  called  "distcc",  or  the  user called
       "nobody".

       distccd does not have a configuration  file;  it's  behaviour  is  con-
       trolled only by command-line options and requests from clients.


STANDALONE SERVER

       The  recommended  method for running distccd is as a standalone server.
       distccd will listen for network connections and fork several child pro-
       cesses to serve them.

       If  you  installed  distcc  using a packaged version you may be able to
       start the server using the standard mechanism for your  operating  sys-
       tem, such as

              # service distcc start

       To  start  distccd  as  a  standalone  service, run a command like this
       either as root or an ordinary user:

              # distccd --daemon


RUNNING FROM INIT

       distccd may be run as a standalone daemon under the control of  another
       program  like  init(8) or daemontools.  The super-server starts distccd
       when the system boots, and whenever it exits.

       distccd should be started just as for a standalone server, except  that
       the --no-detach option should be used so that the super-server can mon-
       itor it.

       For example, to add distccd as a process to Linux  sysvinit,  add  this
       line to /etc/inittab

              dscc:2345:respawn:/usr/local/bin/distccd  --verbose  --no-detach
              --daemon


RUNNING FROM INETD

       distccd may be started from a network super-server  such  as  inetd  or
       xinetd.  In this case inetd listens for network connections and invokes
       distccd when one arrives.

       This is slightly less efficient than running a standalone distccd  dae-
       mon.   distccd  is  not  able to regulate the number of concurrent jobs
       accepted, but there may be an option in your inetd configuration to  do
       so.

       For  traditional  Unix  inetd,  a  line  like  this  can  be  added  to
       /etc/inetd.conf:

              distcc  stream  tcp  nowait.6000   root   /usr/local/bin/distccd
              distccd --inetd

       inetd  imposes  a limit on the rate of connections to a service to pro-
       tect against accidental or intentional overuse.  The default  in  Linux
       NetKit  inetd is 40 per minute, which is far  too low for distccd.  The
       .6000 option raises the limit to 6000 per minute.


TERMINATING DISTCCD

       To shut down a standalone server, send a SIGTERM signal to  the  parent
       process.   The most reliable way to do this from a script is to use the
       --pid-file option to record its process ID.  Shutting down  the  server
       in this way should allow any jobs currently in progress to complete.


OPTIONS

       --help Display summary usage information.

       --version
              Shows the daemon version and exits.

       -j, --jobs JOBS
              Sets  a  limit on the number of jobs that can be accepted at any
              time.  By default this is set to two greater than the number  of
              CPUs  on  the machine, to allow for some processes being blocked
              on network IO.  (Daemon mode only.)

       -N, --nice NICENESS
              Makes the daemon more nice about giving  up  the  CPU  to  other
              tasks  on  the machine.  NICENESS is an increment to the current
              priority of the process.  The range of priorities depends on the
              operating system but is typically 0 to 20.  By default the nice-
              ness is increased by 5.

       -p, --port PORT
              Set the TCP port to listen on, rather than the default of  3632.
              (Daemon mode only.)

       --listen ADDRESS
              Instructs  the  distccd  daemon  to  listen  on  the  IP address
              ADDRESS.  This can be useful for access  control  on  dual-homed
              hosts.  (Daemon mode only.)

       -P, --pid-file FILE
              Save daemon process id to file FILE.  (Daemon mode only.)

       --user USER
              If distccd gets executed as root, change to user USER.

       -a, --allow IPADDR[/MASK]
              Instructs  distccd  to  accept  connections  from the IP address
              IPADDR.  A CIDR mask length can be supplied optionally  after  a
              trailing  slash,  e.g.  192.168.0.0/24,  in which case addresses
              that match in the most significant MASK bits  will  be  allowed.
              If  no  --allow  options are specified, all clients are allowed.
              Unauthorized connections are rejected by closing the TCP connec-
              tion immediately.  A warning is logged on the server but nothing
              is sent ot the client.

       --no-detach
              Do not detach from the shell that started the daemon.

       --no-fork
              Don't fork children for each connection, to allow attaching gdb.
              Don't use this if you don't understand it!

       --log-file FILE
              Send  messages to file FILE instead of syslog.  Logging directly
              to a file is significantly faster than going via syslog  and  is
              recommended.

       --log-level LEVEL
              Set  the  minimum severity of error that will be included in the
              log file.  Useful if you only want to see error messages  rather
              than  an  entry  for  each  connection.  LEVEL can be any of the
              standard syslog levels, and in particular critical, error, warn-
              ing, notice, info, or debug.

       --log-stderr
              Send  log  messages  to stderr, rather than to a file or syslog.
              This is mainly intended for use in debugging.   Do  not  use  in
              inetd mode.

       --verbose
              Include debug messages in log.  Equivalent to --log-level=debug

       --wizard
              Turn  on all options appropriate for starting distccd under gdb:
              run as a daemon, log verbosely to stderr, and do not  detach  or
              fork.  For wizards only.

       --inetd
              Serve a client connected to stdin/stdout.  As the name suggests,
              this option should be used when distccd is  run  from  within  a
              super-server  like inetd.  distccd assumes inetd mode when stdin
              is a socket.

       --daemon
              Bind and listen on a socket, rather  than  running  from  inetd.
              This  is  used for standalone mode.  distccd assumes daemon mode
              at startup if stdin is a tty, so --daemon should  be  explicitly
              specified when starting distccd from a script or in a non-inter-
              active ssh connection.

       --max-cache-age HOURS
              Specifies the maximum time to keep a cached pch file.  The value
              is computed based on the last file access, and is constrained to
              be at most 72 hours (the default).

       --max-cache-size MB
              Specifies the maximum total disk use in Mb allowed for  the  pch
              cache.  A  value  of zero (the default) allows the cache to grow
              without an explicit upper size limit.

       --min-disk-free MB
              Specifies the minimum disk free space in Mb to preserve  on  the
              filesystem  containing  the  pch cache. The default is 2048, and
              the minimum is 512.  --priority PRIORITY  Specifies  an  integer
              priority  for the build machine. Machines with higher priorities
              will be ordered towards the beginning of the  DISTCC_HOSTS  list
              by Xcode. This setting is not used by distcc.


SEARCH PATHS

       distcc  can pass either a relative or an absolute name for the compiler
       to distccd.  If distcc is given an explicit absolute compiler filename,
       that  name is used verbatim on both the client and server.  If the com-
       piler name is not an absolute path, or if the client is  used  in  mas-
       querade mode, then the server's PATH is searched.

       distccd  inherits  its search path from its parent process.  By default
       distccd tries to remove directories that seem to contain  distccd  mas-
       querade   links,   to   guard   against   inadvertent  recursion.   The
       DISTCCD_PATH environment variable may be used to set the path.

       The search path is logged when --verbose is given.  In case  of  confu-
       sion, check the logs.

       When  distccd  is  run over ssh, the $HOME/.ssh/environment file may be
       useful in setting the path.  See ssh(1).


DIAGNOSTICS

       distccd logs messages to syslog's daemon  facility  by  default,  which
       normally  writes to /var/log/daemon or /var/log/messages.  Log messages
       can be sent to a different file using the --log-file option.


ENVIRONMENT VARIABLES

       DISTCCD_PATH
              When starting distccd, if this value is  set  it  will  be  used
              unaltered  for  the  command-execution PATH.  The code that nor-
              mally tries to remove masquerade directories from  the  path  is
              skipped.

       DISTCC_SAVE_TEMPS
              If set to 1, temporary files are not deleted after use.

       Note  that  DISTCC_LOG  does  not  affect  the  log destination for the
       server.

       DISTCC_TCP_DEFER_ACCEPT
              On Linux, turn on the TCP_DEFER_ACCEPT socket option.   Defaults
              to on.

       TMPDIR Directory  for  temporary files such as preprocessor output.  By
              default /tmp/ is used.


PCH CACHING

       The Mac OS X version of distccd includes support for precompiled header
       (pch) files. distccd caches these files in TMPDIR, and provides options
       for managing the cache based on file access times and  disk  use.   The
       pch  files are downloaded from the client machines as needed and stored
       on a per user, per client machine basis. To minimize  build  times  the
       pch  cache should be sufficiently large. If there is insufficient space
       then pch files may be repeatedly downloaded during  a  build.   distccd
       will  emit  a  warning if it detects that the cache constraints require
       discarding recently downloaded pch files (possibly due to a full disk.)


SEE ALSO

       distcc(1), ccache(1), gcc(1), make(1) http://distcc.samba.org/


BUGS

       IP-based  access  control is not secure against attackers able to spoof
       TCP connections, and cannot discriminate different users on a client.

       TCP connections are not secure against attackers  able  to  observe  or
       modify network traffic.

       Because ccache does not cache compilation from .i files, it is not use-
       ful to call it from distccd.


LICENCE

       You are free to use distcc.  distcc  (including  this  manual)  may  be
       copied, modified or distributed only under the terms of the GNU General
       Public Licence version 2 or later.  distcc  comes  with  absolutely  no
       warrany.  A copy of the GPL is included in the file COPYING.


AUTHOR

       distcc  was  written  by Martin Pool <mbp@sourcefrog.net>, with the co-
       operation of many scholars including Wayne Davison, Frerich Raabe, Dim-
       itri  Papadopoulos  and  others  noted in the NEWS file.  Please report
       bugs to <distcc@lists.samba.org>.



                                23 October 2003                     distccd(1)

Mac OS X 10.7 - Generated Fri Nov 4 16:37:57 CDT 2011
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