1.\" Copyright (c) 1999 Berkeley Software Design, Inc. All rights reserved. 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright 9.\" notice, this list of conditions and the following disclaimer in the 10.\" documentation and/or other materials provided with the distribution. 11.\" 3. Berkeley Software Design Inc's name may not be used to endorse or 12.\" promote products derived from this software without specific prior 13.\" written permission. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.Dd April 25, 2024 28.Dt DAEMON 8 29.Os 30.Sh NAME 31.Nm daemon 32.Nd run detached from the controlling terminal 33.Sh SYNOPSIS 34.Nm 35.Op Fl cfHrS 36.Op Fl p Ar child_pidfile 37.Op Fl P Ar supervisor_pidfile 38.Op Fl t Ar title 39.Op Fl u Ar user 40.Op Fl m Ar output_mask 41.Op Fl o Ar output_file 42.Op Fl s Ar syslog_priority 43.Op Fl T Ar syslog_tag 44.Op Fl l Ar syslog_facility 45.Op Fl R Ar restart_delay_seconds 46.Op Fl C Ar restart_count 47.Ar command arguments ... 48.Sh DESCRIPTION 49The 50.Nm 51utility detaches itself from the controlling terminal and 52executes the program specified by its arguments. 53Privileges may be lowered to the specified user. 54The output of the daemonized process may be redirected to syslog and to a 55log file. 56.Pp 57The options are as follows: 58.Bl -tag -width indent 59.It Fl C , Fl -restart-count Ar restart_count 60Restart the process at most 61.Ar restart_count 62times. 63When zero is specified, 64.Nm 65will exit. 66The maximum restart count is 67.Cm 128 . 68This option is used together with option 69.Fl -restart . 70.It Fl c , Fl -change-dir 71Change the current working directory to the root 72.Pq Dq Pa / . 73.It Fl f , Fl -close-fds 74Redirect standard input, standard output and standard error to 75.Pa /dev/null . 76When this option is used together with any of the options related to file 77or syslog output, the standard file descriptors are first redirected to 78.Pa /dev/null , 79then stdout and/or stderr is redirected to a file or to syslog as 80specified by the other options. 81.It Fl H , Fl -sighup 82Close 83.Pa output_file 84and re-open it when signal 85.Dv SIGHUP 86is received, for interoperability with 87.Xr newsyslog 8 88and similar log rotation / archival mechanisms. 89If 90.Fl -output-file 91is not specified, this flag is ignored. 92.It Fl l , Fl -syslog-facility Ar syslog_facility 93These facilities are accepted: 94.Cm auth , authpriv , console , cron , daemon , 95.Cm ftp , kern , lpr , mail , news , ntp , security , 96.Cm syslog , user , uucp , 97and 98local facilities from 99.Cm local0 100to 101.Cm local7 . 102The default is 103.Cm daemon . 104.It Fl m , Fl -output-mask Ar output_mask 105Redirect output from the child process stdout 106.Pq Cm 1 , 107stderr 108.Pq Cm 2 , 109or both 110.Pq Cm 3 . 111This value specifies what is sent to syslog and the log file. 112The default is 113.Cm 3 . 114.It Fl o , Fl -output-file Ar output_file 115Append output from the daemonized process to 116.Pa output_file . 117If the file does not exist, it is created with permissions 0600. 118When this option is used together with options 119.Fl -change-dir 120and 121.Fl -sighup 122the absolute path needs to be provided to ensure 123.Nm 124can re-open the file after a 125.Dv SIGHUP . 126.It Fl P , Fl -supervisor-pidfile Ar supervisor_pidfile 127Write the ID of the 128.Nm 129process into the 130.Ar supervisor_pidfile 131using the 132.Xr pidfile 3 133functionality. 134The program is executed in a spawned child process while the 135.Nm 136waits until it terminates to keep the 137.Ar supervisor_pidfile 138locked and removes it after the process exits. 139The 140.Ar supervisor_pidfile 141owner is the user who runs the 142.Nm 143regardless of whether the 144.Fl -user 145option is used or not. 146.It Fl p , Fl -child-pidfile Ar child_pidfile 147Write the ID of the created process into the 148.Ar child_pidfile 149using the 150.Xr pidfile 3 151functionality. 152The program is executed in a spawned child process while the 153.Nm 154waits until it terminates to keep the 155.Ar child_pidfile 156locked and removes it after the process exits. 157The 158.Ar child_pidfile 159owner is the user who runs the 160.Nm 161regardless of whether the 162.Fl -user 163option is used or not. 164.It Fl R , Fl -restart-delay Ar restart_delay_seconds 165Supervise and restart the program after the specified delay 166if it has been terminated. 167Valid values are 1-31536000 (up to 1 year). 168.It Fl r , Fl -restart 169Supervise and restart the program after a one-second delay if it has 170been terminated. 171.It Fl S , Fl -syslog 172Enable syslog output. 173This is implicitly applied if other syslog parameters are provided. 174The default values are daemon, notice, and daemon for facility, priority, and 175tag, respectively. 176.It Fl s , Fl -syslog-priority Ar syslog_priority 177These priorities are accepted: 178.Cm emerg , alert , crit , err , warning , 179.Cm notice , info , 180and 181.Cm debug . 182The default is 183.Cm notice . 184.It Fl T , Fl -syslog-tag Ar syslog_tag 185Set the tag which is appended to all syslog messages. 186The default is 187.Cm daemon . 188.It Fl t , Fl -title Ar title 189Set the title for the daemon process. 190The default is the daemonized invocation. 191.It Fl u , Fl -user Ar user 192Login name of the user to execute the program under. 193Environment variables 194.Ev HOME , USER , 195and 196.Ev SHELL 197are set accordingly. 198Requires adequate superuser privileges. 199.El 200.Pp 201If any of the options 202.Fl -child-pidfile , 203.Fl -output-mask , 204.Fl -restart , 205.Fl -restart-delay , 206.Fl -supervisor-pidfile , 207.Fl -syslog , 208.Fl -syslog-facility 209.Fl -syslog-priority , 210.Fl -syslog-tag , 211or 212.Fl -output , 213are specified, the program is executed in a spawned child process. 214The 215.Nm 216waits until it terminates to keep the pid file(s) locked and removes them 217after the process exits or restarts the program. 218In this case if the monitoring 219.Nm 220receives software termination signal 221.Pq Dv SIGTERM 222it forwards it to the 223spawned process. 224Normally it will cause the child to exit, remove the pidfile(s) 225and then terminate. 226.Pp 227If neither file or syslog output are selected, all output is redirected to the 228.Nm 229process and written to stdout. 230The 231.Fl -close-fds 232option may be used to suppress the stdout output completely. 233.Pp 234The 235.Fl -supervisor-pidfile 236option is useful combined with the 237.Fl -restart 238option as 239.Ar supervisor_pidfile 240contains the ID of the supervisor 241not the child. 242This is especially important if you use 243.Fl -restart 244in an rc script as the 245.Fl -child-pidfile 246option will give you the child's ID to signal when you attempt to 247stop the service, causing 248.Nm 249to restart the child. 250.Sh EXIT STATUS 251The 252.Nm 253utility exits 1 if an error is returned by the 254.Xr daemon 3 255library routine, 2 if 256.Ar child_pidfile 257or 258.Ar supervisor_pidfile 259is requested, but cannot be opened, 3 if process is already running (pidfile 260exists and is locked), 4 if 261.Ar syslog_priority 262is not accepted, 5 if 263.Ar syslog_facility 264is not accepted, 6 if 265.Ar output_mask 266is not within the accepted range, 7 if 267.Ar output_file 268cannot be opened for appending, and otherwise 0. 269.Sh DIAGNOSTICS 270If the command cannot be executed, an error message is printed to 271standard error. 272The exact behavior depends on the logging parameters and the 273.Fl -close-fds 274flag. 275.Sh SEE ALSO 276.Xr nohup 1 , 277.Xr setregid 2 , 278.Xr setreuid 2 , 279.Xr daemon 3 , 280.Xr exec 3 , 281.Xr pidfile 3 , 282.Xr termios 4 , 283.Xr tty 4 284.Sh HISTORY 285The 286.Nm 287utility first appeared in 288.Fx 4.7 . 289