3 Cygserver is a program which is designed to run as a background service.
4 It provides Cygwin applications with services which require security
5 arbitration or which need to persist while no other cygwin application
8 The implemented services so far are:
10 - Control slave tty/pty handle dispersal from tty owner to other
11 processes without compromising the owner processes' security.
12 - XSI IPC Message Queues.
14 - XSI IPC Shared Memory.
17 Cygserver command line options:
19 Options to Cygserver take the normal UNIX-style `-X' or `--longoption' form.
20 Nearly all options have a counterpart in the configuration file (see below)
21 so setting them on the command line isn't really necessary. Command line
22 options override settings from the Cygserver configuration file.
24 The one-character options are prepended by a single dash, the long variants
25 are prepended with two dashes. Arguments to options are marked in angle
26 brackets below. These are not part of the actual syntax but are used only to
27 denote the arguments. Note that all arguments are required. Cygserver
28 has no options with optional arguments.
30 The options recognized are:
32 -f, --config-file <file>
34 Use <file> as configuration file instead of the default configuration
35 line. The default configuration file is /etc/cygserver.conf, typically.
36 The --help and --version options will print the default configuration
39 This option has no counterpart in the configuration file, for obvious
42 -c, --cleanup-threads <num>
44 Number of threads started to perform cleanup tasks. Default is 2.
45 Configuration file option: kern.srv.cleanup_threads
47 -r, --request-threads <num>
49 Number of threads started to serve application requests. Default is 10.
50 The -c and -r options can be used to play with Cygserver's performance
51 under heavy load conditions or on slow machines.
52 Configuration file option: kern.srv.request_threads
54 -p, --process-cache <num>
56 Number of processes which can connect concurrently to cygserver.
57 Default is 62. Each process connected to cygserver is a synchronization
58 object which has to be maintained. The data structure to maintain these
59 processes is the so-called "process cache". In theory, an arbitrary
60 number of processes could connect to cygserver, but due to the need to
61 synchronize, the higher the number of connected processes, the more
62 synchronization overhead exists. By using this option, you can set an
63 upper limit to the synchronization effort. If more than 62 processes
64 try to connect to cygserver concurrently, two additional synchronization
65 threads are necessary, and one for each further 62 concurrent
66 processes. So, useful values for the --process-cache option are 62, 124,
67 186, 248, 310. 310 is the maximum value.
68 Configuration file option: kern.srv.process_cache_size
70 NOTE: The number of child processes of a single parent process is limited
71 to 256. So in case of taking advantage of a process cache size beyond 256,
72 keep in mind that not all of these processes can be child processes of one
73 single parent process.
77 Log debug messages to stderr. These will clutter your stderr output with
78 a lot of information, typically only useful to developers.
82 Force logging to stderr. This is the default if stderr is connected to
83 a tty. Otherwise, the default is logging to the system log. By using
84 the -e, -E, -y, -Y options (or the appropriate settings in the
85 configuration file), you can explicitely set the logging output as you
86 like, even to both, stderr and syslog.
87 Configuration file option: kern.log.stderr
91 Don't log to stderr. Configuration file option: kern.log.stderr
95 Force logging to the system log. This is the default, if stderr is not
96 connected to a tty, e. g. redirected to a file.
100 Don't log to syslog. Configuration file option: kern.log.syslog
102 -l, --log-level <level>
104 Set the verbosity level of the logging output. Valid values are between
105 1 and 7. The default level is 6, which is relatively chatty. If you set
106 it to 1, you will get only messages which are printed under severe conditions,
107 which will result in stopping Cygserver itself.
108 Configuration file option: kern.log.level
112 Don't start XSI IPC Shared Memory support. If you don't need XSI IPC
113 Shared Memory support, you can switch it off here.
114 Configuration file option: kern.srv.sharedmem
118 Don't start XSI IPC Message Queues.
119 Configuration file option: kern.srv.msgqueues
123 Don't start XSI IPC Semaphores.
124 Configuration file option: kern.srv.semaphores
128 Shutdown a running daemon and exit. Other methods are sending a SIGHUP
129 to the Cygserver PID or, if running as service under NT, calling
130 `net stop cygserver' or `cygrunsrv -E cygserver'.
134 Output usage information and exit.
138 Output version information and exit.
141 How to start Cygserver:
143 Before you run Cygserver for the first time, you should run the
144 /usr/bin/cygserver-config script once. It creates the default
145 configuration file and, upon request, installs Cygserver as service
146 when running under NT. The script only performs a default install,
147 with no further options given to Cygserver when running as service.
148 Due to the wide configurability by changing the configuration file,
149 that's typically not necessary.
151 It's best practice to run Cygserver as a service under LocalSystem
152 account. This is the way it is installed for you by the
153 /usr/bin/cygserver-config script.
156 How to use the Cygserver services:
158 The Cygserver services are used by Cygwin applications only if you
159 set the environment variable CYGWIN to contain the string "server".
160 You must do this before starting the application.
162 Typically, you don't need any other option, so it's ok to set CYGWIN
163 just to "server". It is not necessary to set the CYGWIN environment
164 variable prior to starting the Cygserver process itself, but it won't
167 The easiest way is to set the environment variable CYGWIN to the values
168 you want in the Windows system environment and to reboot the machine.
169 This is advisable, since it allows you to set the variable once and
170 then forget about it. It also ensures that services as well as desktop
171 applications have the same setting.
173 If you don't want that for whatever reason, you can set the
174 variable in the /cygwin.bat file which is used in the net distribution,
175 to start a Cygwin bash from the desktop. In that file, you can set
176 the CYGWIN variable using Windows command line interpreter syntax, e. g.:
180 If you don't set CYGWIN in the system environment, but you're running
181 other Cygwin services, these services need to get that CYGWIN value by
182 setting the environment using the appropriate cygrunsrv option '-e' when
183 installing the service. Example installing a service 'foo':
185 cygrunsrv -I foo -p /usr/sbin/foo -e "CYGWIN=server"
188 The Cygserver configuration file:
190 Cygserver has many options, which allow to customize the server
191 to your needs. Customization is accomplished by editing the configuration
192 file, which is by default /etc/cygserver.conf. This file is read only
193 once on startup of Cygserver. There's no option to re-read the file on
194 runtime by, say, sending a signal to Cygserver.
196 The configuration file determines how Cygserver operates. There are
197 options which set the number of threads running in parallel, options
198 for setting how and what to log and options to set various maximum
199 values for the IPC services.
201 The default configuration file delivered with Cygserver is installed
202 to /etc/defaults/etc. The /usr/bin/cygserver-config script copies it to
203 /etc, giving you the option to overwrite an already existing file or to
204 leave it alone. Therefore, the /etc file is safe to be changed by you,
205 since it will not be overwritten by a later update installation.
207 The default configuration file contains many comments which describe
208 everything needed to understand the settings. A comment at the start of the
209 file describes the syntax rules for the file. The default options are shown
210 in the file but are commented out.
212 It is generally a good idea to uncomment only options which you intend to
213 change from the default values. Since reading the options file on Cygserver
214 startup doesn't take much time, it's also considered good practice to keep
215 all other comments in the file. This keeps you from searching for clues
219 If you have problems with Cygserver, or you have found a bug, or you
220 think you have found a bug, or you don't understand configuration file
221 options, the mailing list <cygwin@cygwin.com> is the right place to ask