usr.sbin/syslogd/syslogd.8

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.\"     from: @(#)syslogd.8	8.1 (Berkeley) 6/6/93
.\"
.Dd October 10, 2004
.Dt SYSLOGD 8
.Os
.Sh NAME
.Nm syslogd
.Nd log systems messages
.Sh SYNOPSIS
.Nm
.Op Fl dnrSs
.Bk -words
.Op Fl f Ar config_file
.Ek
.Bk -words
.Op Fl g Ar group
.Ek
.Bk -words
.Op Fl m Ar mark_interval
.Ek
.Bk -words
.Op Fl P Ar file_list
.Ek
.Bk -words
.Oo
.Fl p Ar log_socket
.Op Fl p Ar log_socket2 ...
.Oc
.Ek
.Bk -words
.Op Fl t Ar chroot_dir
.Ek
.Bk -words
.Op Fl u Ar user
.Ek
.Sh DESCRIPTION
.Nm
reads and logs messages to the system console, log files, other
machines and/or users as specified by its configuration file.
The options are as follows:
.Bl -tag -width 15n
.It Fl d
Enable debugging to the standard output,
and do not disassociate from the controlling terminal.
.It Fl f
Specify the pathname of an alternative configuration file;
the default is
.Pa /etc/syslog.conf .
.It Fl g Ar group
Set GID to
.Ar group
after the sockets and log files have been opened.
.It Fl m
Select the number of minutes between ``mark'' messages;
the default is 20 minutes.
.It Fl n
Do not perform hostname lookups; report only numeric addresses.
.It Fl P
Specify the pathname of a file containing a list of sockets to be
created.
The format of the file is simply one socket per line.
.It Fl p
Specify the pathname of a log socket.
Multiple
.Fl p
options create multiple log sockets.
If no
.Fl p
arguments are created, the default socket of
.Pa /var/run/log
is used.
.It Fl r
Disable the compression of repeated instances of the same line
into a single line of the form
.Dq last message repeated N times .
.It Fl S
Sync kernel messages to disk immediately.
.It Fl s
Select
.Dq secure
mode, in which
.Nm
does not listen on a UDP socket but only communicates over a
.Ux
domain socket.
This is valuable when the machine on
which
.Nm
runs is subject to attack over the network and it is desired
that the machine be protected from attempts to remotely fill logs
and similar attacks.
.It Fl t Ar chroot_dir
.Xr chroot 2
to
.Ar chroot_dir
after the sockets and log files have been opened.
.It Fl u Ar user
Set UID to
.Ar user
after the sockets and log files have been opened.
.El
.Pp
.Nm
reads its configuration file when it starts up and whenever it
receives a hangup signal.
For information on the format of the configuration file,
see
.Xr syslog.conf 5 .
.Pp
.Nm
reads messages from the
.Ux
domain socket
.Pa /var/run/log ,
from an Internet domain socket specified in
.Pa /etc/services ,
and from the special device
.Pa /dev/klog
(to read kernel messages).
.Pp
.Nm
creates the file
.Pa /var/run/syslogd.pid ,
and stores its process
id there.
This can be used to kill or reconfigure
.Nm .
.Pp
By using multiple
.Fl p
options, one can set up many chroot environments by passing the pathname
to the log socket
.Pa ( /var/run/log )
in each chroot area to
.Nm .
For example:
.Dl syslogd -p /var/run/log -p /web/var/run/log -p /ftp/var/run/log
.Pp
Note: the normal log socket must now also be passed to
.Nm .
.Pp
The logged message includes the date, time, and hostname (or pathname of
the log socket).
Commonly, the program name and the process id is included.
.Pp
Accesses from UDP socket can be filtered by libwrap configuration files, like
.Pa /etc/hosts.deny .
Specify
.Dq Li syslogd
in
.Ar daemon_list
portion of the configuration files.
Refer to
.Xr hosts_access 5
for details.
.Ss SYSLOG PROTOCOL NOTES
The message sent to
.Nm
should consist of a single line.
The message can contain a priority code, which should be a preceding
decimal number in angle braces, for example,
.Sq Aq 5 .
This priority code should map into the priorities defined in the
include file
.Aq Pa sys/syslog.h .
.Sh FILES
.Bl -tag -width /var/run/syslogd.pid -compact
.It Pa /etc/syslog.conf
The configuration file.
.It Pa /var/run/syslogd.pid
The process id of current
.Nm .
.It Pa /var/run/log
Name of the
.Ux
domain datagram log socket.
.It Pa /dev/klog
The kernel log device.
.El
.Sh SEE ALSO
.Xr logger 1 ,
.Xr syslog 3 ,
.Xr services 5 ,
.Xr syslog.conf 5 ,
.Xr newsyslog 8
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.3 .
Support for multiple log sockets appeared in
.Nx 1.4 .
libwrap support appeared in
.Nx 1.6 .