.\" Copyright (C) 1995 Andries Brouwer (aeb@cwi.nl)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Written 11 June 1995 by Andries Brouwer <aeb@cwi.nl>
.\" 2008-02-15, Jeremy Kerr <jk@ozlabs.org>
.\"     Add info on command type 10; add details on types 6, 7, 8, & 9.
.\" 2008-02-15, Michael Kerrisk <mtk.manpages@gmail.com>
.\"     Update LOG_BUF_LEN details; update RETURN VALUE section.
.\"
.\" Japanese Version Copyright (c) 1997 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated Mon Dec 16 11:16:34 JST 2001
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated Thu Mar 6 2003 by Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2005-09-06, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2008-04-04, Akihiro MOTOKI, LDP v2.79
.\" Updated 2008-07-31, Akihiro MOTOKI, LDP v3.05
.\"
.\"WORD:	kernel			ͥ
.\"WORD:	message ring buffer	å󥰡Хåե
.\"WORD:	library			饤֥
.\"WORD:	kernel log buffer	ͥ롦Хåե
.\"WORD:	console			󥽡
.\"WORD:	kernel panic		ͥ롦ѥ˥å
.\"WORD:	loglevel		٥
.\"WORD:	debug message		ǥХåå
.\"
.TH SYSLOG 2  2008-06-20 "Linux" "Linux Programmer's Manual"
.SH ̾
syslog, klogctl \- ͥΥå󥰡Хåեɤõꤹ;
console_loglevel Ԥ
.SH 
.nf
.BI "int syslog(int " type ", char *" bufp ", int " len );
.B  "                /* glibc Ǥϥåѡؿ󶡤Ƥʤ */"
.sp
/* glibc Υ󥿥ե */
.br
.B "#include <sys/klog.h>"
.sp
.BI "int klogctl(int " type ", char *" bufp ", int " len );
.fi
.SH 
.RB ( syslogd (8)
ä) C 饤֥ؿ
.BR syslog ()
ɬפʾϡ
.BR syslog (3)
򸫤뤳ȡ
̾Υƥࡦϥͥ
.IR printk ()
Хåե椹ΤǤꡢglibc Ǥ
.BR klogctl ()
ȸƤФƤ롣

\fItype\fP Ϥδؿưꤹ롣

.I kernel/printk.c
ΰ :
.nf
/*
 * Commands to sys_syslog:
 *
 *      0 \-\- Ĥ롣ߤμǤϲ⤷ʤ (NOP) 
 *      1 \-\- 򳫤ߤμǤϲ⤷ʤ (NOP) 
 *      2 \-\- ɤ߽Ф
 *      3 \-\- 󥰡Хåե˻ĤäƤå򤹤٤ɤ߽Ф
 *      4 \-\- 󥰡Хåե˻ĤäƤå򤹤٤ɤ߽Фõ롣
 *      5 \-\- 󥰥Хåեõ롣
 *      6 \-\- 󥽡ؤ printk ̵ˤ롣
 *      7 \-\- 󥽡ؤ printk ͭˤ롣
 *      8 \-\- 󥽡ɽåΥ٥ꤹ롣
 *      9 \-\- Хåե̤ɤʸ֤
 *      10 \-\- ХåեΥ֤
 */
.fi

øץˤϥޥ 3  10 ΤߤĤƤ
(ޥ 9  Linux 2.4.10 ǡޥ 10  Linux 2.6.6 ɲä줿)
.SS ͥ롦Хåե (kernel log buffer)
ͥĹ
.B LOG_BUF_LEN
ν󼰤ΥХåեäƤꡢ
ˤϥͥؿ
.BR printk ()
ΰȤͿ줿
å (Υ٥ˤ餺) Ǽ롣
ΥͥǤ
.B LOG_BUF_LEN
ͤ 4096 Ǥä
ͥ 1.3.54  8192
ͥ 2.1.113  16384 ˤʤꡢ
ͥ 2.4.23 ʹߤ 2.6 ʹߤǤϥͥΥѥ
ͤǤ褦ˤʤäƤ롣
.\" Under "General setup" ==> "Kernel log buffer size"
.\" For 2.6, precisely the option seems to have appeared in 2.5.55.
ǶΥͥǤϡޥ 10 ǥХåեΥ䤤碌Ǥ롣

.I "syslog(2,buf,len)"
θƤӽФϥͥ롦ХåեǤʤʤޤԤäơ
 \fIlen\fP ХȤޤ \fIbuf\fP ؤɤ߽Фɤ߹
Хȿ֤ɤޤ줿ХȤϥХåեä:
ϰ٤ɤळȤǤʤ
ϥ桼Υץब
.I /proc/kmsg
ɤ˥ͥˤäƼ¹ԤؿǤ⤢롣

.I syslog(3,buf,len)
θƤӽФϥХåեκǸ \fIlen\fP ХȤ
(˲Ū)ɤ߽ФľΡ֥󥰡Хåեõ̿
(̿ϥХåեõ櫓ǤϤʤ)
ʹߤ˥Хåե˽񤭹ޤ줿󤷤ɤ߽Фʤ
֤ͤɤ߹ХȿǤ롣

.I syslog(4,buf,len)
ƤӽФϡ֥󥰡Хåեõ̿¹Ԥʳ
ǽ 3 ȴƱǤ롣

.I syslog(5,dummy,dummy)
ƤӽФϡ֥󥰡Хåեõ̿Τߤ¹Ԥ
(ƤӽФν񼰤ǡ
.I buf

.I len
 "dummy" ȵܤƤ硢ΰ̵ͤ뤵뤳Ȥɽ)

.I syslog(6,dummy,dummy)
ƤӽФϥ󥽡Υ٥Ǿꤷ
󥽡˥åɽʤ褦ˤ롣

.I syslog(7,dummy,dummy)
ƤӽФϥ󥽡Υ٥ǥեȤꤷ
󥽡˥åɽ褦ˤ롣

.I syslog(8,dummy,level)
ƤӽФϥ󥽡Υ٥
.I level
ꤹ롣
.I level
 1 ʾ 8 ʲǤʤФʤʤ
ܺ٤
.B ٥ (loglevel)
򻲾ȤΤȡ

.I syslog(9,dummy,dummy)
ƤӽФϥͥ롦Хåեˤ븽ɤ߽ФǽʥХȿ֤

.I syslog(10,dummy,dummy)
ƤӽФϥͥ롦Хåե̤֤
.SS ٥ (loglevel)
ͥ롦롼
.BR printk ()
ϡ٥뤬
.I console_loglevel
ѿ꾮ȤˤΤߡ󥽡˥åɽ롣
.I console_loglevel
Ϻǽ
.B DEFAULT_CONSOLE_LOGLEVEL
(7) ꤵ뤬ư˥ͥ
ޥɡ饤󡦥ץ "debug" Ȥñ줬ޤޤƤ
10 ꤵ졢ͥ롦եȤȯˤ 15 ꤵ
(â10  15 Ȥ˰̣Ϥʤ8 ƱǤ)
ѿ
.IR syslog(8,dummy,value) .
ƤӽФˤäꤵ졢ͤϰϤ 1-8 Ǥ롣
.I syslog(type,dummy,dummy)
ƤӽФ \fItype\fP  6 ⤷ 7 ξ硢
console_loglevel  1 (ͥ롦ѥ˥åΤ)
7 (ǥХååʳ) ˤ줾ꤵ롣

åγƹԤϤ줾˥٥ġΥ٥
.I "DEFAULT_MESSAGE_LOGLEVEL \- 1"
(6) Ǥ뤬 <d> (\fId\fP  1-7 ϰϤο) ǻϤޤԤ
٥ \fId\fP Ǥ롣
٥δŪʰ̣
.I <linux/kernel.h>
˰ʲΤ褦Ƥ:

.nf
#define KERN_EMERG    "<0>"  /* ƥबǽ    	    */
#define KERN_ALERT    "<1>"  /* ľн褬ɬ      	    */
#define KERN_CRIT     "<2>"  /* ̿Ūʾ          	    */
#define KERN_ERR      "<3>"  /* 顼            	    */
#define KERN_WARNING  "<4>"  /* ٹ              	    */
#define KERN_NOTICE   "<5>"  /* ֤̾ʾ	    */
#define KERN_INFO     "<6>"  /*                   	    */
#define KERN_DEBUG    "<7>"  /* ǥХå٥ξ        */
.fi
.SH ֤
\fItype\fP  2, 3, 4 ξ硢
.BR syslog ()
ɤ߽ФХȿ֤
\fItype\fP  9 ξ硢
ͥ롦Хåեˤ븽ɤ߽ФǽʥХȿ֤
\fItype\fP  10 ξ硢
ͥ롦Хåե̤֤
\fItype\fP ʳͤξ硢 0 ֤롣

顼ξϡ\-1\ ֤ꡢ
\fIerrno\fP ˥顼򼨤ͤꤵ롣
.SH 顼
.TP
.B EINVAL
ʰ
(Ūˤϡ
.I type
ʤ⤷
.I type
 2, 3, 4 ξ
.I buf
 NULL 
.I len
 0 ̤Ǥ롢⤷
.I type
 8 ξ
.I level
 1 ʾ 8 ʲϰϤäƤʤ)
.TP
.B EPERM
ʬʸ¤ʤץ (Τˤ
.B CAP_SYS_ADMIN
ѥӥƥʤץ)  console_loglevelѹ褦Ȥ
ͥ롦å󥰤õ褦Ȥ
.TP
.B ERESTARTSYS
ƥࡦ뤬ʥˤäƳޤ졢ɤ߽Фʤä
(ȥ졼ˤȯ뤳ȤϤʤ)
.TP
.B ENOSYS
ͥꥪץ
.BR CONFIG_PRINTK
̵ˤƥͥ뤬ѥ뤵Ƥ뤿ᡢ
.BR syslog ()
ƥॳ뤬ѤǤʤ
.SH 
Υƥࡦ Linux ͭǤꡢܿտޤץǤ
ѤƤϤʤ
.SH 
ʤκ顢Ʊ̾ĥƥࡦ
饤֥ꡦ롼ۤʤʪǤΤԹʤȤ
դƤ
libc4  libc5 ǤϤΥֹ
.B SYS_klog
Ƥ
glibc2.0 ǤΥƥॳ
.BR klogctl ()
Ȥ̾˲줿
.SH Ϣ
.BR syslog (3)