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.\" $FreeBSD$ 28.\" 29.Dd January 14, 2021 30.Dt DAEMON 8 31.Os 32.Sh NAME 33.Nm daemon 34.Nd run detached from the controlling terminal 35.Sh SYNOPSIS 36.Nm 37.Op Fl cfHrS 38.Op Fl p Ar child_pidfile 39.Op Fl P Ar supervisor_pidfile 40.Op Fl t Ar title 41.Op Fl u Ar user 42.Op Fl m Ar output_mask 43.Op Fl o Ar output_file 44.Op Fl s Ar syslog_priority 45.Op Fl T Ar syslog_tag 46.Op Fl l Ar syslog_facility 47.Op Fl R Ar restart_delay_seconds 48.Ar command arguments ... 49.Sh DESCRIPTION 50The 51.Nm 52utility detaches itself from the controlling terminal and 53executes the program specified by its arguments. 54Privileges may be lowered to the specified user. 55The output of the daemonized process may be redirected to syslog and to a 56log file. 57.Pp 58The options are as follows: 59.Bl -tag -width indent 60.It Fl c , Fl -change-dir 61Change the current working directory to the root 62.Pq Dq Pa / . 63.It Fl f , Fl -close-fds 64Redirect standard input, standard output and standard error to 65.Pa /dev/null . 66When this option is used together with any of the options related to file 67or syslog output, the standard file descriptors are first redirected to 68.Pa /dev/null , 69then stdout and/or stderr is redirected to a file or to syslog as 70specified by the other options. 71.It Fl H , Fl -sighup 72Close 73.Pa output_file 74and re-open it when signal SIGHUP is received, for interoperability with 75.Xr newsyslog 1 76and similar log rotation / archival mechanisms. If 77.Fl -output-file 78is not specified, this flag is ignored. 79.It Fl S , Fl -syslog 80Enable syslog output. 81This is implicitly applied if other syslog parameters are provided. 82The default values are daemon, notice, and daemon for facility, priority, and 83tag, respectively. 84.It Fl o , Fl -output-file Ar output_file 85Append output from the daemonized process to 86.Pa output_file . 87If the file does not exist, it is created with permissions 0600. 88When this option is used together with options 89.Fl -change-dir 90and 91.Fl -sighup 92the absolute path needs to be provided to ensure 93.Nm 94can re-open the file after a SIGHUP. 95.It Fl m , Fl -output-mask Ar output_mask 96Redirect output from the child process stdout (1), stderr (2), or both (3). 97This value specifies what is sent to syslog and the log file. 98The default is 3. 99.It Fl p , Fl -child-pidfile Ar child_pidfile 100Write the ID of the created process into the 101.Ar child_pidfile 102using the 103.Xr pidfile 3 104functionality. 105The program is executed in a spawned child process while the 106.Nm 107waits until it terminates to keep the 108.Ar child_pidfile 109locked and removes it after the process exits. 110The 111.Ar child_pidfile 112owner is the user who runs the 113.Nm 114regardless of whether the 115.Fl -user 116option is used or not. 117.It Fl P , Fl -supervisor-pidfile Ar supervisor_pidfile 118Write the ID of the 119.Nm 120process into the 121.Ar supervisor_pidfile 122using the 123.Xr pidfile 3 124functionality. 125The program is executed in a spawned child process while the 126.Nm 127waits until it terminates to keep the 128.Ar supervisor_pidfile 129locked and removes it after the process exits. 130The 131.Ar supervisor_pidfile 132owner is the user who runs the 133.Nm 134regardless of whether the 135.Fl -user 136option is used or not. 137.It Fl r , Fl -restart 138Supervise and restart the program after a one-second delay if it has 139been terminated. 140.It Fl R , Fl -restart-delay Ar restart_delay_seconds 141Supervise and restart the program after the specified delay 142if it has been terminated. 143.It Fl t , Fl -title Ar title 144Set the title for the daemon process. 145The default is the daemonized invocation. 146.It Fl u , Fl -user Ar user 147Login name of the user to execute the program under. 148Requires adequate superuser privileges. 149.It Fl s , Fl -syslog-priority Ar syslog_priority 150These priorities are accepted: emerg, alert, crit, err, warning, 151notice, info, and debug. 152The default is notice. 153.It Fl l , Fl -syslog-facility Ar syslog_facility 154These facilities are accepted: auth, authpriv, console, cron, daemon, 155ftp, kern, lpr, mail, news, ntp, security, syslog, user, uucp, and 156local0, ..., local7. 157The default is daemon. 158.It Fl T , Fl -syslog-tag Ar syslog_tag 159Set the tag which is appended to all syslog messages. 160The default is daemon. 161.El 162.Pp 163If any of the options 164.Fl -child-pidfile , 165.Fl -output-mask , 166.Fl -restart , 167.Fl -restart-delay , 168.Fl -supervisor-pidfile , 169.Fl -syslog , 170.Fl -syslog-facility 171.Fl -syslog-priority , 172.Fl -syslog-tag , 173or 174.Fl -output , 175are specified, the program is executed in a spawned child process. 176The 177.Nm 178waits until it terminates to keep the pid file(s) locked and removes them 179after the process exits or restarts the program. 180In this case if the monitoring 181.Nm 182receives software termination signal (SIGTERM) it forwards it to the 183spawned process. 184Normally it will cause the child to exit, remove the pidfile(s) 185and then terminate. 186.Pp 187If neither file or syslog output are selected, all output is redirected to the 188.Nm 189process and written to stdout. 190The 191.Fl -close-fds 192option may be used to suppress the stdout output completely. 193.Pp 194The 195.Fl -supervisor-pidfile 196option is useful combined with the 197.Fl -restart 198option as 199.Ar supervisor_pidfile 200contains the ID of the supervisor 201not the child. 202This is especially important if you use 203.Fl -restart 204in an rc script as the 205.Fl -child-pidfile 206option will give you the child's ID to signal when you attempt to 207stop the service, causing 208.Nm 209to restart the child. 210.Sh EXIT STATUS 211The 212.Nm 213utility exits 1 if an error is returned by the 214.Xr daemon 3 215library routine, 2 if 216.Ar child_pidfile 217or 218.Ar supervisor_pidfile 219is requested, but cannot be opened, 3 if process is already running (pidfile 220exists and is locked), 4 if 221.Ar syslog_priority 222is not accepted, 5 if 223.Ar syslog_facility 224is not accepted, 6 if 225.Ar output_mask 226is not within the accepted range, 7 if 227.Ar output_file 228cannot be opened for appending, and otherwise 0. 229.Sh DIAGNOSTICS 230If the command cannot be executed, an error message is printed to 231standard error. 232The exact behavior depends on the logging parameters and the 233.Fl -close-fds 234flag. 235.Sh SEE ALSO 236.Xr nohup 1 , 237.Xr setregid 2 , 238.Xr setreuid 2 , 239.Xr daemon 3 , 240.Xr exec 3 , 241.Xr pidfile 3 , 242.Xr termios 4 , 243.Xr tty 4 244.Sh HISTORY 245The 246.Nm 247utility first appeared in 248.Fx 4.7 . 249