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: head/usr.sbin/daemon/daemon.8 353025 2019-10-02 23:19:34Z ian $ 28.\" 29.Dd May 14, 2020 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 cfrS 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 61Change the current working directory to the root 62.Pq Dq Pa / . 63.It Fl f 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 S 72Enable syslog output. 73This is implicitly applied if other syslog parameters are provided. 74The default values are daemon, notice, and daemon for facility, priority, and 75tag, respectively. 76.It Fl o Ar output_file 77Append output from the daemonized process to 78.Pa output_file . 79If the file does not exist, it is created with permissions 0600. 80For a proper automatic log file rotation of programs started with 81.Nm 82it is recommended to create a PID file with the 83.Fl p 84option and configure 85.Xr newsyslog.conf 5 86to send 87.Dv SIGUSR1 88to the process ID in this file. 89.It Fl m Ar output_mask 90Redirect output from the child process stdout (1), stderr (2), or both (3). 91This value specifies what is sent to syslog and the log file. 92The default is 3. 93.It Fl p Ar child_pidfile 94Write the ID of the created process into the 95.Ar child_pidfile 96using the 97.Xr pidfile 3 98functionality. 99The program is executed in a spawned child process while the 100.Nm 101waits until it terminates to keep the 102.Ar child_pidfile 103locked and removes it after the process exits. 104The 105.Ar child_pidfile 106owner is the user who runs the 107.Nm 108regardless of whether the 109.Fl u 110option is used or not. 111.It Fl P Ar supervisor_pidfile 112Write the ID of the 113.Nm 114process into the 115.Ar supervisor_pidfile 116using the 117.Xr pidfile 3 118functionality. 119The program is executed in a spawned child process while the 120.Nm 121waits until it terminates to keep the 122.Ar supervisor_pidfile 123locked and removes it after the process exits. 124The 125.Ar supervisor_pidfile 126owner is the user who runs the 127.Nm 128regardless of whether the 129.Fl u 130option is used or not. 131.It Fl r 132Supervise and restart the program after a one-second delay if it has 133been terminated. 134.It Fl R Ar restart_delay_seconds 135Supervise and restart the program after the specified delay 136if it has been terminated. 137.It Fl t Ar title 138Set the title for the daemon process. 139The default is the daemonized invocation. 140.It Fl u Ar user 141Login name of the user to execute the program under. 142Requires adequate superuser privileges. 143.It Fl s Ar syslog_priority 144These priorities are accepted: emerg, alert, crit, err, warning, 145notice, info, and debug. 146The default is notice. 147.It Fl l Ar syslog_facility 148These facilities are accepted: auth, authpriv, console, cron, daemon, 149ftp, kern, lpr, mail, news, ntp, security, syslog, user, uucp, and 150local0, ..., local7. 151The default is daemon. 152.It Fl T Ar syslog_tag 153Set the tag which is appended to all syslog messages. 154The default is daemon. 155.El 156.Pp 157If any of the options 158.Fl p , 159.Fl P , 160.Fl r , 161.Fl o , 162.Fl s , 163.Fl T , 164.Fl m , 165.Fl S , 166or 167.Fl l 168are specified, the program is executed in a spawned child process. 169The 170.Nm 171waits until it terminates to keep the pid file(s) locked and removes them 172after the process exits or restarts the program. 173In this case if the monitoring 174.Nm 175receives software termination signal (SIGTERM) it forwards it to the 176spawned process. 177Normally it will cause the child to exit, remove the pidfile(s) 178and then terminate. 179.Pp 180If neither file or syslog output are selected, all output is redirected to the 181.Nm 182process and written to stdout. 183The 184.Fl f 185option may be used to suppress the stdout output completely. 186.Pp 187The 188.Fl P 189option is useful combined with the 190.Fl r 191option as 192.Ar supervisor_pidfile 193contains the ID of the supervisor 194not the child. 195This is especially important if you use 196.Fl r 197in an rc script as the 198.Fl p 199option will give you the child's ID to signal when you attempt to 200stop the service, causing 201.Nm 202to restart the child. 203.Sh EXIT STATUS 204The 205.Nm 206utility exits 1 if an error is returned by the 207.Xr daemon 3 208library routine, 2 if 209.Ar child_pidfile 210or 211.Ar supervisor_pidfile 212is requested, but cannot be opened, 3 if process is already running (pidfile 213exists and is locked), 4 if 214.Ar syslog_priority 215is not accepted, 5 if 216.Ar syslog_facility 217is not accepted, 6 if 218.Ar output_mask 219is not within the accepted range, 7 if 220.Ar output_file 221cannot be opened for appending, and otherwise 0. 222.Sh DIAGNOSTICS 223If the command cannot be executed, an error message is printed to 224standard error. 225The exact behavior depends on the logging parameters and the 226.Fl f 227flag. 228.Sh SEE ALSO 229.Xr nohup 1 , 230.Xr setregid 2 , 231.Xr setreuid 2 , 232.Xr daemon 3 , 233.Xr exec 3 , 234.Xr pidfile 3 , 235.Xr termios 4 , 236.Xr tty 4 , 237.Xr newsyslog.conf 5 238.Sh HISTORY 239The 240.Nm 241utility first appeared in 242.Fx 4.7 . 243