1.\" $NetBSD: syslog.3,v 1.3 1995/02/27 05:52:39 cgd Exp $ 2.\" 3.\" Copyright (c) 1985, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)syslog.3 8.1 (Berkeley) 6/4/93 35.\" 36.Dd June 4, 1993 37.Dt SYSLOG 3 38.Os BSD 4.2 39.Sh NAME 40.Nm syslog , 41.Nm vsyslog , 42.Nm openlog , 43.Nm closelog , 44.Nm setlogmask 45.Nd control system log 46.Sh SYNOPSIS 47.Fd #include <syslog.h> 48.Fd #include <varargs.h> 49.Ft void 50.Fn syslog "int priority" "const char *message" "..." 51.Ft void 52.Fn vsyslog "int priority" "const char *message" "va_list args" 53.Ft void 54.Fn openlog "const char *ident" "int logopt" "int facility" 55.Ft void 56.Fn closelog void 57.Ft int 58.Fn setlogmask "int maskpri" 59.Sh DESCRIPTION 60The 61.Fn syslog 62function 63writes 64.Fa message 65to the system message logger. 66The message is then written to the system console, log files, 67logged-in users, or forwarded to other machines as appropriate. (See 68.Xr syslogd 8 . ) 69.Pp 70The message is identical to a 71.Xr printf 3 72format string, except that 73.Ql %m 74is replaced by the current error 75message. (As denoted by the global variable 76.Va errno ; 77see 78.Xr strerror 3 . ) 79A trailing newline is added if none is present. 80.Pp 81The 82.Fn vsyslog 83function 84is an alternate form in which the arguments have already been captured 85using the variable-length argument facilities of 86.Xr varargs 3 . 87.Pp 88The message is tagged with 89.Fa priority . 90Priorities are encoded as a 91.Fa facility 92and a 93.Em level . 94The facility describes the part of the system 95generating the message. 96The level is selected from the following 97.Em ordered 98(high to low) list: 99.Bl -tag -width LOG_AUTHPRIV 100.It Dv LOG_EMERG 101A panic condition. 102This is normally broadcast to all users. 103.It Dv LOG_ALERT 104A condition that should be corrected immediately, such as a corrupted 105system database. 106.It Dv LOG_CRIT 107Critical conditions, e.g., hard device errors. 108.It Dv LOG_ERR 109Errors. 110.It Dv LOG_WARNING 111Warning messages. 112.It Dv LOG_NOTICE 113Conditions that are not error conditions, 114but should possibly be handled specially. 115.It Dv LOG_INFO 116Informational messages. 117.It Dv LOG_DEBUG 118Messages that contain information 119normally of use only when debugging a program. 120.El 121.Pp 122The 123.Fn openlog 124function 125provides for more specialized processing of the messages sent 126by 127.Fn syslog 128and 129.Fn vsyslog . 130The parameter 131.Fa ident 132is a string that will be prepended to every message. 133The 134.Fa logopt 135argument 136is a bit field specifying logging options, which is formed by 137.Tn OR Ns 'ing 138one or more of the following values: 139.Bl -tag -width LOG_AUTHPRIV 140.It Dv LOG_CONS 141If 142.Fn syslog 143cannot pass the message to 144.Xr syslogd 145it will attempt to write the message to the console 146.Pq Dq Pa /dev/console. 147.It Dv LOG_NDELAY 148Open the connection to 149.Xr syslogd 150immediately. 151Normally the open is delayed until the first message is logged. 152Useful for programs that need to manage the order in which file 153descriptors are allocated. 154.It Dv LOG_PERROR 155Write the message to standard error output as well to the system log. 156.It Dv LOG_PID 157Log the process id with each message: useful for identifying 158instantiations of daemons. 159.El 160.Pp 161The 162.Fa facility 163parameter encodes a default facility to be assigned to all messages 164that do not have an explicit facility encoded: 165.Bl -tag -width LOG_AUTHPRIV 166.It Dv LOG_AUTH 167The authorization system: 168.Xr login 1 , 169.Xr su 1 , 170.Xr getty 8 , 171etc. 172.It Dv LOG_AUTHPRIV 173The same as 174.Dv LOG_AUTH , 175but logged to a file readable only by 176selected individuals. 177.It Dv LOG_CRON 178The clock daemon. 179.It Dv LOG_DAEMON 180System daemons, such as 181.Xr routed 8 , 182that are not provided for explicitly by other facilities. 183.It Dv LOG_KERN 184Messages generated by the kernel. 185These cannot be generated by any user processes. 186.It Dv LOG_LPR 187The line printer spooling system: 188.Xr lpr 1 , 189.Xr lpc 8 , 190.Xr lpd 8 , 191etc. 192.It Dv LOG_MAIL 193The mail system. 194.It Dv LOG_NEWS 195The network news system. 196.It Dv LOG_SYSLOG 197Messages generated internally by 198.Xr syslogd 8 . 199.It Dv LOG_USER 200Messages generated by random user processes. 201This is the default facility identifier if none is specified. 202.It Dv LOG_UUCP 203The uucp system. 204.It Dv LOG_LOCAL0 205Reserved for local use. 206Similarly for 207.Dv LOG_LOCAL1 208through 209.Dv LOG_LOCAL7 . 210.El 211.Pp 212The 213.Fn closelog 214function 215can be used to close the log file. 216.Pp 217The 218.Fn setlogmask 219function 220sets the log priority mask to 221.Fa maskpri 222and returns the previous mask. 223Calls to 224.Fn syslog 225with a priority not set in 226.Fa maskpri 227are rejected. 228The mask for an individual priority 229.Fa pri 230is calculated by the macro 231.Fn LOG_MASK pri ; 232the mask for all priorities up to and including 233.Fa toppri 234is given by the macro 235.Fn LOG_UPTO toppri ; . 236The default allows all priorities to be logged. 237.Sh RETURN VALUES 238The routines 239.Fn closelog , 240.Fn openlog , 241.Fn syslog 242and 243.Fn vsyslog 244return no value. 245.Pp 246The routine 247.Fn setlogmask 248always returns the previous log mask level. 249.Sh EXAMPLES 250.Bd -literal -offset indent -compact 251syslog(LOG_ALERT, "who: internal error 23"); 252 253openlog("ftpd", LOG_PID, LOG_DAEMON); 254setlogmask(LOG_UPTO(LOG_ERR)); 255syslog(LOG_INFO, "Connection from host %d", CallingHost); 256 257syslog(LOG_INFO|LOG_LOCAL2, "foobar error: %m"); 258.Ed 259.Sh SEE ALSO 260.Xr logger 1 , 261.Xr syslogd 8 262.Sh HISTORY 263These 264functions appeared in 265.Bx 4.2 . 266