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