1distccd(1) General Commands Manual distccd(1)
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6 distccd - distributed C/C++ compiler server
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9 distccd --daemon [OPTIONS]
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12 distccd is the server for the distcc(1) distributed compiler. It
13 accepts and runs compilation jobs for network clients.
14 distcc can run over either TCP or a connection command such as ssh(1).
16 TCP connections are fast but relatively insecure. SSH connections are
17 secure but slower.
18 For SSH connections, distccd must be installed on the volunteer but
20 should not run as a daemon -- it will be started over SSH as needed.
21 SSH connections have several advantages: neither the client nor server
22 listens on any new ports; compilations run with the privileges of the
23 user that requested them; unauthorized users cannot access the server;
24 and source and output is protected in transit.
25 For TCP connections, distccd can run either from an inetd-style pro‐
27 gram, or as a standalone server. Standalone mode is recommended
28 because it is slightly more efficient and allows distccd to regulate
29 the number of incoming jobs. The --listen and --allow options can be
30 used for simple IP-based access control.
31 distcc may be started either by root or any other user. If run by
33 root, it gives away privileges and changes to the user specified by the
34 --user option, or the user called "distcc", or the user called
35 "nobody".
36 distccd does not have a configuration file; it's behaviour is con‐
38 trolled only by command-line options and requests from clients.
39
41 The recommended method for running distccd is as a standalone server.
42 distccd will listen for network connections and fork several child pro‐
43 cesses to serve them.
44 If you installed distcc using a packaged version you may be able to
46 start the server using the standard mechanism for your operating sys‐
47 tem, such as
48 # service distcc start
50 To start distccd as a standalone service, run a command like this
52 either as root or an ordinary user:
53 # distccd --daemon
55
57 distccd may be run as a standalone daemon under the control of another
58 program like init(8) or daemontools. The super-server starts distccd
59 when the system boots, and whenever it exits.
60 distccd should be started just as for a standalone server, except that
62 the --no-detach option should be used so that the super-server can mon‐
63 itor it.
64 For example, to add distccd as a process to Linux sysvinit, add this
66 line to /etc/inittab
67 dscc:2345:respawn:/usr/local/bin/distccd --verbose --no-detach
69 --daemon
70
72 distccd may be started from a network super-server such as inetd or
73 xinetd. In this case inetd listens for network connections and invokes
74 distccd when one arrives.
75 This is slightly less efficient than running a standalone distccd dae‐
77 mon. distccd is not able to regulate the number of concurrent jobs
78 accepted, but there may be an option in your inetd configuration to do
79 so.
80 For traditional Unix inetd, a line like this can be added to
82 /etc/inetd.conf:
83 distcc stream tcp nowait.6000 root /usr/local/bin/distccd
85 distccd --inetd
86 inetd imposes a limit on the rate of connections to a service to pro‐
88 tect against accidental or intentional overuse. The default in Linux
89 NetKit inetd is 40 per minute, which is far too low for distccd. The
90 .6000 option raises the limit to 6000 per minute.
91
93 To shut down a standalone server, send a SIGTERM signal to the parent
94 process. The most reliable way to do this from a script is to use the
95 --pid-file option to record its process ID. Shutting down the server
96 in this way should allow any jobs currently in progress to complete.
97
99 --help Display summary usage information.
100 --version
102 Shows the daemon version and exits.
103 -j, --jobs JOBS
105 Sets a limit on the number of jobs that can be accepted at any
106 time. By default this is set to two greater than the number of
107 CPUs on the machine, to allow for some processes being blocked
108 on network IO. (Daemon mode only.)
109 -N, --nice NICENESS
111 Makes the daemon more nice about giving up the CPU to other
112 tasks on the machine. NICENESS is an increment to the current
113 priority of the process. The range of priorities depends on the
114 operating system but is typically 0 to 20. By default the nice‐
115 ness is increased by 5.
116 -p, --port PORT
118 Set the TCP port to listen on, rather than the default of 3632.
119 (Daemon mode only.)
120 --listen ADDRESS
122 Instructs the distccd daemon to listen on the IP address
123 ADDRESS. This can be useful for access control on dual-homed
124 hosts. (Daemon mode only.)
125 -P, --pid-file FILE
127 Save daemon process id to file FILE. (Daemon mode only.)
128 --user USER
130 If distccd gets executed as root, change to user USER.
131 -a, --allow IPADDR[/MASK]
133 Instructs distccd to accept connections from the IP address
134 IPADDR. A CIDR mask length can be supplied optionally after a
135 trailing slash, e.g. 192.168.0.0/24, in which case addresses
136 that match in the most significant MASK bits will be allowed.
137 If no --allow options are specified, distccd will exit immedi‐
138 ately! Unauthorized connections are rejected by closing the TCP
139 connection immediately. A warning is logged on the server but
140 nothing is sent to the client.
141 --job-lifetime SECONDS
143 Kills a distccd job if it runs for more than SECONDS seconds.
144 This prevents denial of service from clients that don't properly
145 disconnect and compilers that fail to terminate. By default this
146 is turned off.
147 --no-detach
149 Do not detach from the shell that started the daemon.
150 --no-fork
152 Don't fork children for each connection, to allow attaching gdb.
153 Don't use this if you don't understand it!
154 --log-file FILE
156 Send messages to file FILE instead of syslog. Logging directly
157 to a file is significantly faster than going via syslog and is
158 recommended.
159 --log-level LEVEL
161 Set the minimum severity of error that will be included in the
162 log file. Useful if you only want to see error messages rather
163 than an entry for each connection. LEVEL can be any of the
164 standard syslog levels, and in particular critical, error, warn‐
165 ing, notice, info, or debug.
166 --log-stderr
168 Send log messages to stderr, rather than to a file or syslog.
169 This is mainly intended for use in debugging. Do not use in
170 inetd mode.
171 --verbose
173 Include debug messages in log. Equivalent to --log-level=debug
174 --wizard
176 Turn on all options appropriate for starting distccd under gdb:
177 run as a daemon, log verbosely to stderr, and do not detach or
178 fork. For wizards only.
179 --stats
181 Turn on the statistics HTTP server. By default it is off. (Dae‐
182 mon mode only.)
183 --stats-port PORT
185 Set the TCP port to listen on for HTTP requests, rather than the
186 default of 3633. (Daemon mode only.)
187 --inetd
189 Serve a client connected to stdin/stdout. As the name suggests,
190 this option should be used when distccd is run from within a
191 super-server like inetd. distccd assumes inetd mode when stdin
192 is a socket.
193 --daemon
195 Bind and listen on a socket, rather than running from inetd.
196 This is used for standalone mode. distccd assumes daemon mode
197 at startup if stdin is a tty, so --daemon should be explicitly
198 specified when starting distccd from a script or in a non-inter‐
199 active ssh connection.
200 --zeroconf
202 Register the availability of this distccd server using Avahi
203 Zeroconf DNS Service Discovery (DNS-SD). This allows distcc
204 clients on the local network to access this distccd server with‐
205 out explicitly listing its host name or IP address in their
206 distcc host list: the distcc clients can just use "+zeroconf" in
207 their distcc host lists. This option is only available if
208 distccd was compiled with Avahi support enabled.
209 --auth Peform GSS-API based mutual authentication. This option is only
211 available if distccd was compiled with the --with-auth configure
212 option.
213 --show-principal
215 Displays the name of the distccd security principal extracted
216 from the environment. This option is only available if distccd
217 was compiled with the --with-auth configure option.
218 --blacklist=FILE
220 Instruct distccd to reject connections from users whose princi‐
221 pal names are listed in FILE. This option is only available if
222 distccd was compiled with the --with-auth configure option and
223 if distccd is run with the --auth option.
224 --whitelist=FILE
226 Instruct distccd to accept connections only from users whose
227 principal names are listed in FILE. This option is only avail‐
228 able if distccd was compiled with the --with-auth configure
229 option and if distccd is run with the --auth option.
230
232 distcc can pass either a relative or an absolute name for the compiler
233 to distccd. If distcc is given an explicit absolute compiler filename,
234 that name is used verbatim on both the client and server. If the com‐
235 piler name is not an absolute path, or if the client is used in mas‐
236 querade mode, then the server's PATH is searched.
237 distccd inherits its search path from its parent process. By default
239 distccd tries to remove directories that seem to contain distccd mas‐
240 querade links, to guard against inadvertent recursion. The
241 DISTCCD_PATH environment variable may be used to set the path.
242 The search path is logged when --verbose is given. In case of confu‐
244 sion, check the logs.
245 When distccd is run over ssh, the $HOME/.ssh/environment file may be
247 useful in setting the path. See ssh(1).
248
250 distccd logs messages to syslog's daemon facility by default, which
251 normally writes to /var/log/daemon or /var/log/messages. Log messages
252 can be sent to a different file using the --log-file option.
253
255 DISTCC_CMDLIST
256 If the environment variable DISTCC_CMDLIST is set, load a list
257 of supported commands from the file named by DISTCC_CMDLIST, and
258 refuse to serve any command whose last DISTCC_CMDLIST_MATCHWORDS
259 last words do not match those of a command in that list. See
260 the comments in src/serve.c.
261 DISTCC_CMDLIST_NUMWORDS
263 The number of words, from the end of the command, to match. The
264 default is 1.
265 DISTCCD_PATH
267 When starting distccd, if this value is set it will be used
268 unaltered for the command-execution PATH. The code that nor‐
269 mally tries to remove masquerade directories from the path is
270 skipped.
271 DISTCC_SAVE_TEMPS
273 If set to 1, temporary files are not deleted after use.
274 Note that DISTCC_LOG does not affect the log destination for the
276 server.
277 DISTCC_TCP_DEFER_ACCEPT
279 On Linux, turn on the TCP_DEFER_ACCEPT socket option. Defaults
280 to on.
281 TMPDIR Directory for temporary files such as preprocessor output. By
283 default /tmp/ is used.
284 DISTCCD_PRINCIPAL
286 If set, specifies the name of the principal that distccd runs
287 under, and is used to authenticate with the client. This envi‐
288 ronment variable is only used if distccd was compiled with the
289 --with-auth configure option and if distccd is run with the
290 --auth option.
291
293 distcc(1), pump(1), include_server(1), gcc(1), make(1), and ccache(1)
294 http://code.google.com/p/distcc/
295
297 IP-based access control is not secure against attackers able to spoof
298 TCP connections, and cannot discriminate different users on a client.
299 TCP connections are not secure against attackers able to observe or
301 modify network traffic.
302 Because ccache does not cache compilation from .i files, it is not use‐
304 ful to call it from distccd.
305
307 You are free to use distcc. distcc (including this manual) may be
308 copied, modified or distributed only under the terms of the GNU General
309 Public Licence version 2 or later. distcc comes with absolutely no
310 warrany. A copy of the GPL is included in the file COPYING.
311
313 distcc was written by Martin Pool <mbp@sourcefrog.net>, with the co-
314 operation of many scholars including Wayne Davison, Frerich Raabe, Dim‐
315 itri Papadopoulos and others noted in the NEWS file. See pump(1) for
316 the authors of pump mode. Please report bugs to
317 <distcc@lists.samba.org>.
318 9 June 2008 distccd(1)