[linuxjm/LDP_man-pages.git] / draft / man5 / utmp.5

.\" Copyright (c) 1993 Michael Haardt (michael@cantor.informatik.rwth-aachen.de),
.\" Fri Apr  2 11:32:09 MET DST 1993
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License, or (at your option) any later version.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, write to the Free
.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
.\" USA.
.\"
.\" Modified 1993-07-25 by Rik Faith (faith@cs.unc.edu)
.\" Modified 1995-02-26 by Michael Haardt
.\" Modified 1996-07-20 by Michael Haardt
.\" Modified 1997-07-02 by Nicolas Lichtmaier <nick@debian.org>
.\" Modified 2004-10-31 by aeb, following Gwenole Beauchesne
.\"
.\" Japanese Version Copyright (c) 1997 Kazuyuki Tanisako
.\"         all rights reserved.
.\" Translated 1998-02-16, Kazuyuki Tanisako <tanisako@osa.dec-j.co.jp>
.\" Updated 2003-01-20, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2005-02-21, Akihiro MOTOKI
.\" Updated 2005-10-06, Akihiro MOTOKI
.\" Updated 2008-08-11, Akihiro MOTOKI, LDP v3.05
.\"
.TH UTMP 5 2008-10-10 "Linux" "Linux Programmer's Manual"
.\"O .SH NAME
.SH ̾Á°
.\"O utmp, wtmp \- login records
utmp, wtmp \- ¥í¥°¥¤¥óµ­Ï¿
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.B #include <utmp.h>
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O The
.\"O .I utmp
.\"O file allows one to discover information about who is currently using the
.\"O system.
.\"O There may be more users currently using the system, because not
.\"O all programs use utmp logging.
.I utmp
¥Õ¥¡¥¤¥ë¤ò¸«¤ë¤³¤È¤Ç¡¢¸½ºß郎¥·¥¹¥Æ¥à¤ò»È¤Ã¤Æ¤¤¤ë¤«¤È¤¤¤¦¾ðÊó
¤¬ÆÀ¤é¤ì¤ë¡£¤¿¤À¤¹¤Ù¤Æ¤Î¥×¥í¥°¥é¥à¤¬ utmp ¥Õ¥¡¥¤¥ë¤ò
¹¹¿·¤·¤Æ¤¤¤ë¤ï¤±¤Ç¤Ï¤Ê¤¤¤Î¤Ç¡¢¼ÂºÝ¤Ë¤Ï¤½¤ì°Ê¾å¤Î¥æ¡¼¥¶¡¼¤¬
¥·¥¹¥Æ¥à¤ò»È¤Ã¤Æ¤¤¤ë²ÄǽÀ­¤¬¤¢¤ë¡£
.PP
.\"O .B Warning:
.\"O .I utmp
.\"O must not be writable by the user class "other",
.\"O because many system programs (foolishly)
.\"O depend on its integrity.
.\"O You risk faked system logfiles and
.\"O modifications of system files if you leave
.\"O .I utmp
.\"O writable to any user other than the owner and group owner of the file.
.B ·Ù¹ð:
(¶ò¤«¤Ë¤â) ¿¤¯¤Î¥·¥¹¥Æ¥à¥×¥í¥°¥é¥à¤¬¤½¤ÎÀ°¹çÀ­¤Ë°Í¸¤·¤Æ¤¤¤ë¤Î¤Ç¡¢
.I utmp
¥Õ¥¡¥¤¥ë¤Ï "other" ¤ËʬÎव¤ì¤ë¥æ¡¼¥¶¤ËÂФ·¤Æ
½ñ¤­¹þ¤ß²Äǽ¤Ë¤·¤Æ¤Ï¤Ê¤é¤Ê¤¤¡£
¥Õ¥¡¥¤¥ë¤Î½êÍ­¼Ô¤È¥°¥ë¡¼¥×¥ª¡¼¥Ê¡¼°Ê³°¤Î¥æ¡¼¥¶¤ËÂФ·¤Æ
.I utmp
¥Õ¥¡¥¤¥ë¤ò½ñ¤­¹þ¤ß²Äǽ¤Ê¾õÂ֤ˤ·¤Æ¤ª¤¯¤È¡¢
¥·¥¹¥Æ¥à¤Î¥í¥°¥Õ¥¡¥¤¥ë¤òµ¶Â¤¤µ¤ì¤¿¤ê¡¢¥·¥¹¥Æ¥à¥Õ¥¡¥¤¥ë¤Î
²þ¤¶¤ó¤ò¼õ¤±¤ë¤È¤¤¤Ã¤¿¥ê¥¹¥¯¤òÈȤ¹¤³¤È¤Ë¤Ê¤ë¡£
.PP
.\"O The file is a sequence of
.\"O .I utmp
.\"O structures,
.\"O declared as follows in
.\"O .IR <utmp.h>
.\"O (note that this is only one of several definitions
.\"O around; details depend on the version of libc):
¤³¤Î¥Õ¥¡¥¤¥ë¤Ï
.I utmp
¹½Â¤ÂΤ竤êÊÖ¤·¤Ç¹½À®¤µ¤ì¤ë¡£
¤³¤Î¹½Â¤ÂΤÏ
.I <utmp.h>
¤Ç°Ê²¼¤Î¤è¤¦¤ËÄêµÁ¤µ¤ì¤Æ¤¤¤ë
(¤³¤³¤Ëµ­½Ò¤·¤Æ¤¢¤ë¤Î¤Ï´ö¤Ä¤«¤ÎÂç¤Þ¤«¤ÊÄêµÁ¤Î¤ß¤Ç¡¢
¾ÜºÙ¤Ï libc ¤Î¥Ð¡¼¥¸¥ç¥ó¤Ë¤è¤êÊѤï¤ë¤³¤È¤ËÃí°Õ¤¬É¬ÍפǤ¢¤ë)¡£
.in +4n
.nf
.sp
/* Values for ut_type field, below */

#define EMPTY         0 /* Record does not contain valid info
                           (formerly known as UT_UNKNOWN on Linux) */
#define RUN_LVL       1 /* Change in system run-level (see
                           \fBinit\fP(8)) */
#define BOOT_TIME     2 /* Time of system boot (in \fIut_tv\fP) */
#define NEW_TIME      3 /* Time after system clock change
                           (in \fIut_tv\fP) */
#define OLD_TIME      4 /* Time before system clock change
                           (in \fIut_tv\fP) */
#define INIT_PROCESS  5 /* Process spawned by \fBinit\fP(8) */
#define LOGIN_PROCESS 6 /* Session leader process for user login */
#define USER_PROCESS  7 /* Normal process */
#define DEAD_PROCESS  8 /* Terminated process */
#define ACCOUNTING    9 /* Not implemented */

#define UT_LINESIZE      32
#define UT_NAMESIZE      32
#define UT_HOSTSIZE     256

struct exit_status {              /* Type for ut_exit, below */
    short int e_termination;      /* Process termination status */
    short int e_exit;             /* Process exit status */
};

struct utmp {
    short   ut_type;              /* Type of record */
    pid_t   ut_pid;               /* PID of login process */
    char    ut_line[UT_LINESIZE]; /* Device name of tty \- "/dev/" */
    char    ut_id[4];             /* Terminal name suffix,
                                     or inittab(5) ID */
    char    ut_user[UT_NAMESIZE]; /* Username */
    char    ut_host[UT_HOSTSIZE]; /* Hostname for remote login, or
                                     kernel version for run-level
                                     messages */
    struct  exit_status ut_exit;  /* Exit status of a process
                                     marked as DEAD_PROCESS; not
                                     used by Linux init(8) */
.\"O     /* The ut_session and ut_tv fields must be the same size when
.\"O        compiled 32- and 64-bit.  This allows data files and shared
.\"O        memory to be shared between 32- and 64-bit applications. */
    /* ut_session ¤È ut_tv ¥Õ¥£¡¼¥ë¥É¤Ï¡¢32¥Ó¥Ã¥È¤Ç¥³¥ó¥Ñ¥¤¥ë¤µ¤ì¤¿¾ì¹ç¤È
       64¥Ó¥Ã¥È¤Ç¥³¥ó¥Ñ¥¤¥ë¤µ¤ì¤¿¾ì¹ç¤ÇƱ¤¸¥µ¥¤¥º¤Ç¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£
       ¤³¤¦¤¹¤ë¤³¤È¤Ç¡¢32¥Ó¥Ã¥È¤È64¥Ó¥Ã¥È¤Î¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¤Ç¡¢
       ¥Ç¡¼¥¿¥Õ¥¡¥¤¥ë¤È¶¦Í­¥á¥â¥ê¤ò¶¦Í­¤¹¤ë¤³¤È¤¬¤Ç¤­¤ë¤è¤¦¤Ë¤Ê¤ë¡£ */

#if __WORDSIZE == 64 && defined __WORDSIZE_COMPAT32
    int32_t ut_session;           /* Session ID (\fBgetsid\fP(2)),
                                     used for windowing */
    struct {
        int32_t tv_sec;           /* Seconds */
        int32_t tv_usec;          /* Microseconds */
    } ut_tv;                      /* Time entry was made */
#else
     long   ut_session;           /* Session ID */
     struct timeval ut_tv;        /* Time entry was made */
#endif

    int32_t ut_addr_v6[4];        /* Internet address of remote
                                     host; IPv4 address uses
                                     just ut_addr_v6[0] */
    char __unused[20];            /* Reserved for future use */
};

/* Backward compatibility hacks */
#define ut_name ut_user
#ifndef _NO_UT_TIME
#define ut_time ut_tv.tv_sec
#endif
#define ut_xtime ut_tv.tv_sec
#define ut_addr ut_addr_v6[0]
.sp
.fi
.in
.\"O This structure gives the name of the special file associated with the
.\"O user's terminal, the user's login name, and the time of login in the form
.\"O of
.\"O .BR time (2).
.\"O String fields are terminated by \fB\(aq\e0\(aq\fP
.\"O if they are shorter than the size
.\"O of the field.
¤³¤Î¹½Â¤ÂΤ«¤é¥æ¡¼¥¶¡¼¤Î»È¤Ã¤Æ¤¤¤ëüËö¤Î¥¹¥Ú¥·¥ã¥ë¥Õ¥¡¥¤¥ë̾¡¢
¥æ¡¼¥¶¡¼¤Î¥í¥°¥¤¥ó̾¡¢
.RB ( time (2)
·Á¼°¤Ç¤Î)¥í¥°¥¤¥ó»þ¹ï¤¬¤ï¤«¤ë¡£Ê¸»úÎó¥Õ¥£¡¼¥ë¥É¤Ï¡¢
¥Õ¥£¡¼¥ë¥É¤ÎŤµ¤è¤êʸ»úÎó¤¬Ã»¤¤¾ì¹ç¤Ë¤Ï¡¢\fB\(aq\e0\(aq\fP ¤Ë¤è¤Ã¤Æ½ªÃ¼¤µ¤ì¤ë¡£
.PP
.\"O The first entries ever created result from
.\"O .BR init (8)
.\"O processing
.\"O .BR inittab (5).
.\"O Before an entry is processed, though,
.\"O .BR init (8)
.\"O cleans up utmp by setting \fIut_type\fP to \fBDEAD_PROCESS\fP, clearing
.\"O \fIut_user\fP, \fIut_host\fP, and \fIut_time\fP with null bytes for each
.\"O record which \fIut_type\fP is not \fBDEAD_PROCESS\fP or \fBRUN_LVL\fP
.\"O and where no process with PID \fIut_pid\fP exists.
.\"O If no empty record
.\"O with the needed \fIut_id\fP can be found,
.\"O .BR init (8)
.\"O creates a new one.
.\"O It sets \fIut_id\fP from the inittab, \fIut_pid\fP and \fIut_time\fP to the
.\"O current values, and \fIut_type\fP to \fBINIT_PROCESS\fP.
ºÇ½é¤Î¥¨¥ó¥È¥ê¤Ï
.BR init (8)
¥³¥Þ¥ó¥É¤¬
.BR inittab (5)
¤ò½èÍý¤¹¤ë¤³¤È¤Çºî¤é¤ì¤ë¡£
¤¢¤ë¥¨¥ó¥È¥ê¤ò½èÍý¤¹¤ëÁ°¤Ë¡¢
.BR init (8)
¤Ï \fIut_type\fP ¤ò \fBDEAD_PROCESS\fP ¤Ë½é´ü²½¤¹¤ë¡£
¥ì¥³¡¼¥É¤Î
\fIut_type\fP ¤¬ \fBDEAD_PROCESS\fP ¤È \fBRUN_LVL\fP ¤Î¤¤¤º¤ì¤Ç¤â¤Ê¤¯¡¢
¤«¤Ä PID ¤¬ \fIut_pid\fP ¤Ç¤¢¤ë¥×¥í¥»¥¹¤¬¤¤¤Ê¤¤¾ì¹ç¤Ï¡¢\fIut_user\fP,
\fIut_host\fP, \fIut_time\fP ¤ò¥Ì¥ë¥Ð¥¤¥È¤Ç¥¯¥ê¥¢¤·¤Æ½é´ü²½¤ò¹Ô¤¦¡£
ɬÍ×¤Ê \fIut_id\fP ¤ò»ý¤Ä¶õ¤Î¥ì¥³¡¼¥É¤ò¸«¤Ä¤±¤é¤ì¤Ê¤«¤Ã¤¿¾ì¹ç¡¢
.BR init (8)
¤Ï¿·¤·¤¤¥ì¥³¡¼¥É¤òºî¤ë¡£inittab ¤«¤é \fIut_id\fP ¤òÀßÄꤷ¡¢
\fIut_pid\fP ¤ª¤è¤Ó \fIut_time\fP ¤ò¸½ºßÃͤˡ¢
\fIut_type\fP ¤ò \fBINIT_PROCESS\fP ¤ËÀßÄꤹ¤ë¡£
.PP
.\"O .BR mingetty (8)
.\"O (or
.\"O .BR agetty (8))
.\"O locates the entry by the PID, changes \fIut_type\fP to
.\"O \fBLOGIN_PROCESS\fP, changes \fIut_time\fP, sets \fIut_line\fP, and waits
.\"O for connection to be established.
.\"O .BR login (1),
.\"O after a user has been
.\"O authenticated, changes \fIut_type\fP to \fBUSER_PROCESS\fP, changes
.\"O \fIut_time\fP, and sets \fIut_host\fP and \fIut_addr\fP.
.\"O Depending on
.\"O .BR mingetty (8)
.\"O (or
.\"O .BR agetty (8))
.\"O and
.\"O .BR login (1),
.\"O records may be located by
.\"O \fIut_line\fP instead of the preferable \fIut_pid\fP.
.BR mingetty (8)
(¤Þ¤¿¤Ï
.BR agetty (8))
¤Ï pid ¤Ç¥¨¥ó¥È¥ê¤òÆÃÄꤷ¡¢
\fIut_type\fP ¤ò \fBLOGIN_PROCESS\fP ¤ËÊѹ¹¤·¡¢
\fIut_time\fP ¤ò¹¹¿·¤·¡¢\fIut_line\fP¤òÀßÄꤷ¤¿¸å¡¢Àܳ¤¬³ÎΩ¤µ¤ì¤ë¤Î¤òÂԤġ£
.BR login (1)
¤Ï¥æ¡¼¥¶¡¼Ç§¾Ú¤¬½ªÎ»¤¹¤ë¤È¡¢
\fIut_type\fP ¤ò \fBUSER_PROCESS\fP ¤ËÊѹ¹¤·¡¢
\fIut_time\fP ¤ò¹¹¿·¤·¡¢\fIut_host\fP ¤È \fIut_addr\fP¤òÀßÄꤹ¤ë¡£
.BR mingetty (8)
(¤Þ¤¿¤Ï
.BR agetty (8))
¤È
.BR login (1)
¤Ë¤è¤ê°Û¤Ê¤ë¤¬¡¢
\fIut_pid\fP ¤ÎÂå¤ï¤ê¤Ë
\fIut_line\fP ¤ò»È¤Ã¤Æ¥ì¥³¡¼¥É¤ÎÆÃÄ꤬¹Ô¤ï¤ì¤ë¤³¤È¤â¤¢¤ë
(\fIut_pid\fP ¤ò»È¤¦Êý¤¬Ë¾¤Þ¤·¤¤) ¡£
.PP
.\"O When
.\"O .BR init (8)
.\"O finds that a process has exited, it locates its utmp
.\"O entry by \fIut_pid\fP, sets \fIut_type\fP to \fBDEAD_PROCESS\fP, and
.\"O clears \fIut_user\fP, \fIut_host\fP and \fIut_time\fP with null bytes.
.BR init (8)
¤Ï¥×¥í¥»¥¹¤Î½ªÎ»¤ò¸¡½Ð¤·¤¿¾ì¹ç¡¢
\fIut_pid\fP ¤ò¥­¡¼¤È¤·¤Æ utmp ¤Î¥¨¥ó¥È¥ê¤òÆÃÄꤷ¡¢
\fIut_type\fP ¤ò \fBDEAD_PROCESS\fP ¤ËÀßÄꤷ¡¢
\fIut_user\fP, \fIut_host\fP, \fIut_time\fP ¤ò¥Ì¥ë¥Ð¥¤¥È¤Ç¥¯¥ê¥¢¤¹¤ë¡£
.PP
.\"O .BR xterm (1)
.\"O and other terminal emulators directly create a
.\"O \fBUSER_PROCESS\fP record and generate the \fIut_id\fP by using the
.\"O string that suffix part of the terminal name (the characters
.\"O following \fI/dev/[pt]ty\fP).
.\"O If they find a \fBDEAD_PROCESS\fP for this ID,
.\"O they recycle it, otherwise they create a new entry.
.\"O If they can, they
.\"O will mark it as \fBDEAD_PROCESS\fP on exiting and it is advised that
.\"O they null \fIut_line\fP, \fIut_time\fP, \fIut_user\fP, and \fIut_host\fP
.\"O as well.
.BR xterm (1)
¥³¥Þ¥ó¥É¤ä¾¤ÎüËö¥¨¥ß¥å¥ì¡¼¥¿¤Ï
ľÀÜ \fBUSER_PROCESS\fP ¤Î¥ì¥³¡¼¥É¤òºî¤ê¡¢
üËö̾¤Î¥µ¥Õ¥£¥Ã¥¯¥¹Ê¸»úÎó (\fI/dev/[pt]ty\fP ¤Ë³¤¯Ê¸»úÎó)
¤ò»È¤Ã¤Æ \fIut_id\fP ¤ÎÃͤòÀ¸À®¤¹¤ë¡£
¤³¤Î id ¤ò»ý¤Ä¥¨¥ó¥È¥ê¤¬ \fBDEAD_PROCESS\fP ¤Ç¤¢¤Ã¤¿¾ì¹ç¤Ë¤ÏºÆÍøÍѤ·¡¢
¤½¤ì°Ê³°¤Î¾ì¹ç¤Ë¤Ï¿·¤·¤¤¥¨¥ó¥È¥ê¤¬ºî¤é¤ì¤ë¡£
²Äǽ¤Ê¾ì¹ç¤Ë¤Ï¥×¥í¥»¥¹½ªÎ»»þ¤Ë \fBDEAD_PROCESS\fP ¤ÈÀßÄꤷ¡¢
¤µ¤é¤Ë \fIut_line\fP, \fIut_time\fP, \fIut_user\fP, \fIut_host\fP
¤ò¥Ì¥ë¥Ð¥¤¥È¤Ç¥¯¥ê¥¢¤¹¤ë¤³¤È¤¬¾©Î夵¤ì¤Æ¤¤¤ë¡£
.PP
.\"O sets up a \fBLOGIN_PROCESS\fP entry and leaves the rest to
.\"O .BR login (1)
.\"O as usual.
.\"O After the telnet session ends,
.\"O .BR telnetd (8)
.\"O cleans up utmp in the described way.
.BR telnetd (8)
¤Ï \fBLOGIN_PROCESS\fP ¤òÀßÄꤹ¤ë¤À¤±¤Ç¤è¤¯¡¢
»Ä¤ê¤Î½èÍý¤ÏÄ̾ïÄ̤ê
.BR login (1)
¤ËǤ¤»¤ì¤Ð¤è¤¤¡£
telnet ¤Î¥»¥Ã¥·¥ç¥ó¤¬½ªÎ»¤·¤¿¸å¡¢Á°½Ò¤Î¤è¤¦¤Ë
.BR telnetd (8)
¤¬ utmp ¤Î¥¨¥ó¥È¥ê¤ò½é´ü²½¤¹¤ë¡£
.PP
.\"O The \fIwtmp\fP file records all logins and logouts.
.\"O Its format is exactly like \fIutmp\fP except that a null username
.\"O indicates a logout
.\"O on the associated terminal.
.\"O Furthermore, the terminal name \fB~\fP
.\"O with username \fBshutdown\fP or \fBreboot\fP indicates a system
.\"O shutdown or reboot and the pair of terminal names \fB|\fP/\fB}\fP
.\"O logs the old/new system time when
.\"O .BR date (1)
.\"O changes it.
.\"O \fIwtmp\fP is maintained by
.\"O .BR login (1),
.\"O .BR init (8),
.\"O and some versions of
.\"O .BR getty (8)
.\"O (e.g.,
.\"O .BR mingetty (8)
.\"O or
.\"O .BR agetty (8)).
.\"O None of these programs creates the file, so if it is
.\"O removed, record-keeping is turned off.
\fIwtmp\fP ¥Õ¥¡¥¤¥ë¤Ë¤Ï¡¢¤¹¤Ù¤Æ¤Î¥í¥°¥¤¥ó¤È¥í¥°¥¢¥¦¥È¤¬µ­Ï¿¤µ¤ì¤ë¡£
¤½¤Î¥Õ¥©¡¼¥Þ¥Ã¥È¤Ï¡¢¥í¥°¥¢¥¦¥ÈºÑ¤ÎüËö¤Ç¥æ¡¼¥¶¡¼Ì¾¤¬¥Ì¥ë¤È¤Ê¤ë¤³¤È°Ê³°¤Ï
\fIutmp\fP ¤È¤Þ¤Ã¤¿¤¯Æ±¤¸¤Ç¤¢¤ë¡£
¥æ¡¼¥¶¡¼Ì¾¤¬ \fBshutdown\fP ¤â¤·¤¯¤Ï \fBreboot\fP ¤Ç¤¢¤ë
üËö̾ \fB~\fP ¤Ï¥·¥¹¥Æ¥à¤ÎÄä»ß (shutdown) ¤Þ¤¿¤ÏºÆµ¯Æ° (reboot)
¤ò°ÕÌ£¤¹¤ë¡£¤Þ¤¿¤½¤ÎüËö̾¤¬ \fB|\fP ¤È \fB}\fP ¤ÎÂФÏ
.BR date (1)
¥³¥Þ¥ó¥É¤ÇÊѹ¹¤·¤¿¿·¡¿µì¤Î¥·¥¹¥Æ¥à»þ¹ï¤òµ­Ï¿¤·¤Æ¤¤¤ë¡£
\fIwtmp\fP ¥Õ¥¡¥¤¥ë¤Ï
.BR login (1),
.BR init (8)
¤ä¤¤¤¯¤Ä¤«¤Î¥Ð¡¼¥¸¥ç¥ó¤Î
.BR getty (8)
.RB ( mingetty (8)
¤Þ¤¿¤Ï
.BR agetty (8))
¤Ë¤è¤ê´ÉÍý¤µ¤ì¤Æ¤¤¤ë¡£
¤³¤ì¤é¤Î¥×¥í¥°¥é¥à¤Ï¤É¤ì¤â¥Õ¥¡¥¤¥ë¤ò¿·¤¿¤ËºîÀ®¤·¤Ê¤¤¤Î¤Ç¡¢
¥Õ¥¡¥¤¥ë¤òºï½ü¤¹¤ë¤³¤È¤Ç¾ðÊó¤Îµ­Ï¿ (record-keeping) ¤ò»ß¤á¤ë¤³¤È¤¬¤Ç¤­¤ë¡£
.\"O .SH FILES
.SH ¥Õ¥¡¥¤¥ë
/var/run/utmp
.br
/var/log/wtmp
.\"O .SH "CONFORMING TO"
.SH ½àµò
.PP
.\"O POSIX.1 does not specify a
.\"O .I utmp
.\"O structure, but rather one named
.\"O .IR utmpx ,
.\"O with specifications for the fields
.\"O .IR ut_type ,
.\"O .IR ut_pid ,
.\"O .IR ut_line ,
.\"O .IR ut_id ,
.\"O .IR ut_user ,
.\"O and
.\"O .IR ut_tv .
.\"O POSIX.1 does not specify the lengths of the
.\"O .I ut_line
.\"O and
.\"O .I ut_user
.\"O fields.
POSIX.1 ¤Ç¤Ï¡¢
.I utmp
¹½Â¤ÂΤǤϤʤ¯¡¢
.I utmpx
¹½Â¤ÂΤòµ¬Äꤷ¤Æ¤¤¤ë¡£
.I utmpx
¹½Â¤ÂΤǵ¬Äꤵ¤ì¤Æ¤¤¤ë¤Î¤Ï¡¢¥Õ¥£¡¼¥ë¥É
.IR ut_type ,
.IR ut_pid ,
.IR ut_line ,
.IR ut_id ,
.IR ut_user ,
.IR ut_tv
¤Ç¤¢¤ë¡£
POSIX.1 ¤Ç¤Ï¡¢¥Õ¥£¡¼¥ë¥É
.I ut_line
¤È
.I ut_user
¤ÎŤµ¤Ïµ¬Äꤵ¤ì¤Æ¤¤¤Ê¤¤¡£

.\"O Linux defines the
.\"O .I utmpx
.\"O structure to be the same as the
.\"O .I utmp
.\"O structure.
Linux ¤Ç¤Ï¡¢
.I utmpx
¹½Â¤ÂΤÎÄêµÁ¤Ï
.I utmp
¹½Â¤ÂΤÈƱ¤¸¤Ç¤¢¤ë¡£
.\"O .SS Comparison with Historical Systems
.SS ²áµî¤Î¥·¥¹¥Æ¥à¤È¤ÎÈæ³Ó
.\"O Linux utmp entries conform neither to v7/BSD nor to System V; they are a
.\"O mix of the two.
Linux ¤Ç¤Î utmp ¤Î¥¨¥ó¥È¥ê¤Ï v7/BSD ¤ä System V ¤Î¤¤¤º¤ì¤Ë¤â½àµò¤·¤Æ¤ª¤é¤º¡¢
¤½¤ÎξÊý¤¬º®ºß¤·¤¿¤â¤Î¤Ç¤¢¤ë¡£

.\"O v7/BSD has fewer fields; most importantly it lacks
.\"O \fIut_type\fP, which causes native v7/BSD-like programs to display (for
.\"O example) dead or login entries.
.\"O Further, there is no configuration file
.\"O which allocates slots to sessions.
.\"O BSD does so because it lacks \fIut_id\fP fields.
v7/BSD ¤Ç¤Ï¤è¤ê¾¯¤·¤Î¹àÌܤ·¤«¤Ê¤¤;
¤â¤Ã¤È¤â½ÅÍפʤ³¤È¤Ï¡¢\fIut_type\fP ¤¬Ìµ¤¤¤³¤È¤Ç¤¢¤ë¡£
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BSD ¤ËÀßÄê¥Õ¥¡¥¤¥ë¤¬¤¢¤ë¤Î¤Ï \fIut_id\fP ¤¬¤Ê¤¤¤«¤é¤Ç¤¢¤ë¡£

.\"O In Linux (as in System V), the \fIut_id\fP field of a
.\"O record will never change once it has been set, which reserves that slot
.\"O without needing a configuration file.
.\"O Clearing \fIut_id\fP may result
.\"O in race conditions leading to corrupted utmp entries and potential
.\"O security holes.
.\"O Clearing the abovementioned fields by filling them
.\"O with null bytes is not required by System V semantics,
.\"O but makes it possible to run
.\"O many programs which assume BSD semantics and which do not modify utmp.
.\"O Linux uses the BSD conventions for line contents, as documented above.
Linux (System V ·Ï)¤Ç¤Ï¡¢ÀßÄê¥Õ¥¡¥¤¥ë¤òɬÍפȤ»¤º
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¤µ¤ì¤Æ¤·¤Þ¤¦¤È¥ì¥³¡¼¥É¤Î \fIut_id\fP ¤Ï·è¤·¤ÆÊѹ¹¤µ¤ì¤Ê¤¤¡£
\fIut_id\fP ¤ò¥¯¥ê¥¢¤¹¤ë¤È¶¥¹ç¾õÂ֤ˤª¤Á¤¤¤ê¡¢
utmp ¤Î¥¨¥ó¥È¥ê¤ò²õ¤·¤¿¤ê¡¢ÀøºßŪ¤Ê¥»¥­¥å¥ê¥Æ¥£¥Û¡¼¥ë¤Ë¤Ê¤ë²ÄǽÀ­¤¬¤¢¤ë¡£
¾å½Ò¤Î¥Õ¥£¡¼¥ë¥É¤ò NULL ¥Ð¥¤¥È¤ÇËä¤á¤Æ¥¯¥ê¥¢¤·¤Æ¤ª¤¯¤Î¤Ï¡¢
System V ¤Ç¤Î¼è¤ê·è¤á¤Ç¤ÏɬÍפȤϤµ¤ì¤Æ¤¤¤Ê¤¤¤¬¡¢
BSD ¤Ç¤Î¼è¤ê·è¤á¤òÁ°Äó¤È¤·¤Æ¤¤¤Æ¡¢¤«¤Ä utmp ¤ò¹¹¿·¤·¤Ê¤¤Â¿¤¯¤Î¥×¥í¥°¥é¥à¤¬
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.PP
.\"O .\" mtk: What is the referrent of "them" in the following sentence?
.\"O .\" System V only uses the type field to mark them and logs
.\"O .\" informative messages such as \fB"new time"\fP in the line field.
.\"O System V has no \fIut_host\fP or \fIut_addr_v6\fP fields.
.\" mtk: What is the referrent of "them" in the following sentence?
.\" System V ¤Ç¤Ï ut_type ¤òÌÜ°õ¤Ë¤·¤¿¤ê¡¢¤¿¤È¤¨¤Ð \fB"new time"\fP ¤Î¤è¤¦¤Ê
.\" ÄÌÃÎ¥á¥Ã¥»¡¼¥¸¤òµ­Ï¿¤¹¤ë¤¿¤á¤Î¤ß¤Ë»È¤Ã¤Æ¤¤¤ë¡£
\fBUT_UNKNOWN\fP ¤Ï Linux ¤Çºî¤é¤ì¤¿¤â¤Î¤Î¤è¤¦¤Ç¤¢¤ë¡£
System V ¤Ë¤Ï \fIut_host\fP ¤â \fIut_addr_v6\fP ¤â¸ºß¤·¤Ê¤¤¡£
.\"O .SH NOTES
.SH Ãí°Õ
.PP
.\"O Unlike various other
.\"O systems, where utmp logging can be disabled by removing the file, utmp
.\"O must always exist on Linux.
.\"O If you want to disable
.\"O .BR who (1)
.\"O then
.\"O do not make utmp world readable.
¥Õ¥¡¥¤¥ë¤òºï½ü¤¹¤ë¤³¤È¤Ç utmp ¤Ø¤Îµ­Ï¿¤ò»ß¤á¤é¤ì¤ë
¾¤ÎÍÍ¡¹¤Ê¥·¥¹¥Æ¥à¤È¤Ï°ã¤¤¡¢Linux ¤Ç¤Ï utmp ¥Õ¥¡¥¤¥ë¤òɬ¤º¤ª¤¤¤Æ
¤ª¤¯É¬Íפ¬¤¢¤ë¡£
.BR who (1)
¥³¥Þ¥ó¥É¤¬µ¡Ç½¤·¤Ê¤¤¤è¤¦¤Ë¤·¤¿¤¤¾ì¹ç¤Ë¤Ï¡¢
utmp ¥Õ¥¡¥¤¥ë¤ÎÁ´¥æ¡¼¥¶¡¼¤ËÂФ¹¤ëÆɤ߼è¤êµö²Ä¤òÀßÄꤷ¤Ê¤¤¤è¤¦¤Ë¤¹¤ë¡£
.PP
.\"O The file format is machine-dependent, so it is recommended that it be
.\"O processed only on the machine architecture where it was created.
¥Õ¥¡¥¤¥ë¤Î¥Õ¥©¡¼¥Þ¥Ã¥È¤Ï¥Þ¥·¥ó¤Ë°Í¸¤¹¤ë¤Î¤Ç¡¢¥Õ¥¡¥¤¥ë¤¬ºî¤é¤ì¤¿
¥Þ¥·¥ó¤â¤·¤¯¤ÏƱ°ì¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤Î¥Þ¥·¥ó¾å¤Ç¤Î¤ß½èÍý¤¹¤ë¤³¤È¤ò¿ä¾©¤¹¤ë¡£
.PP
.\"O Note that on \fIbiarch\fP platforms, that is, systems which can run both
.\"O 32-bit and 64-bit applications (x86-64, ppc64, s390x, etc.),
.\"O \fIut_tv\fP is the same size in 32-bit mode as in 64-bit mode.
.\"O The same goes for \fIut_session\fP and \fIut_time\fP if they are present.
.\"O This allows data files and shared memory to be shared between
.\"O 32-bit and 64-bit applications.
Ãí°Õ¤¹¤Ù¤­ÅÀ¤È¤·¤Æ¤Ï¡¢
\fIbiarch\fP ¤Ê¥×¥é¥Ã¥È¥Õ¥©¡¼¥à¡¢¤Ä¤Þ¤ê 32¥Ó¥Ã¥È¤È 64¥Ó¥Ã¥È¤ÎξÊý¤Î
¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¤ò¼Â¹Ô¤Ç¤­¤ë¥·¥¹¥Æ¥à (x86-64, ppc64, s390x ¤Ê¤É) ¤Ç¤Ï¡¢
\fIut_tv\fP ¤Î¥µ¥¤¥º¤Ï 32¥Ó¥Ã¥È¥â¡¼¥É¤È 64¥Ó¥Ã¥È¥â¡¼¥É¤ÇƱ¤¸¤Ç¤¢¤ë¡£
\fIut_session\fP ¤È \fIut_time\fP ¤â¡¢Â¸ºß¤¹¤ë¾ì¹ç¤Ë¤ÏƱÍͤËƱ¤¸¥µ¥¤¥º
¤Ç¤¢¤ë¡£¤³¤ì¤Ë¤è¤ê¡¢32¥Ó¥Ã¥È¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¤È 64¥Ó¥Ã¥È¥¢¥×¥ê¥±¡¼¥·¥ç¥ó
¤Î´Ö¤Ç¥Ç¡¼¥¿¥Õ¥¡¥¤¥ë¤È¶¦Í­¥á¥â¥ê¤ò¶¦Í­¤¹¤ë¤³¤È¤¬²Äǽ¤Ë¤Ê¤ë¡£
.\"O This is achieved by changing the type of
.\"O .I ut_session
.\"O to
.\"O .IR int32_t ,
.\"O and that of
.\"O .I ut_tv
.\"O to a struct with two
.\"O .I int32_t
.\"O fields
.\"O .I tv_sec
.\"O and
.\"O .IR tv_usec .
¤½¤Î¤¿¤á¤Ë¤Ï¡¢
.I ut_session
¤ò
.I int32_t
·¿¤Ë¡¢
.I ut_tv
¤ò 2¤Ä¤Î
.I int32_t
·¿¤Î¥Õ¥£¡¼¥ë¥É
.IR tv_sec ,
.I tv_usec
¤ò»ý¤Ä¹½Â¤ÂΤËÊѹ¹¤¹¤ì¤Ð¤è¤¤
.\"O Since \fIut_tv\fP may not be the same as \fIstruct timeval\fP,
.\"O then instead of the call:
\fIut_tv\fP ¤Ï \fIstruct timeval\fP ¤ÈƱ¤¸¥µ¥¤¥º¤È¤Ï¸Â¤é¤Ê¤¤¤Î¤Ç¡¢
.in +4n
.nf
.sp
gettimeofday((struct timeval *) &ut.ut_tv, NULL);
.fi
.in

¤Î¤è¤¦¤Ê¸Æ¤Ó½Ð¤·¤ò¤¹¤ë¤Î¤Ç¤Ï¤Ê¤¯¡¢
.\"O the following method of setting this field is recommended:
°Ê²¼¤Î¤è¤¦¤Ë³Æ¥Õ¥£¡¼¥ë¥É¤òÀßÄꤹ¤ëÊýË¡¤¬¿ä¾©¤µ¤ì¤ë:
.in +4n
.nf
.sp
struct utmp ut;
struct timeval tv;

gettimeofday(&tv, NULL);
ut.ut_tv.tv_sec = tv.tv_sec;
ut.ut_tv.tv_usec = tv.tv_usec;
.fi
.in
.PP
.\"O Note that the \fIutmp\fP struct from libc5 has changed in libc6.
.\"O Because of this,
.\"O binaries using the old libc5 struct will corrupt
.\"O .IR /var/run/utmp " and/or " /var/log/wtmp .
utmp ¹½Â¤ÂÎ¤Ï libc5 ¤«¤é libc6 ¤ÇÊѹ¹¤µ¤ì¤¿¡£¤½¤Î¤¿¤áÀΤΠlibc5 ¤Î¹½Â¤ÂÎ
¤ò»È¤Ã¤¿¥×¥í¥°¥é¥à¤Ï
.IR /var/run/utmp " ¤ä " /var/log/wtmp
¥Õ¥¡¥¤¥ë¤ò²õ¤·¤Æ¤·¤Þ¤¦¡£
.\"O .SH BUGS
.SH ¥Ð¥°
.\"O This man page is based on the libc5 one, things may work differently now.
¤³¤Î man ¥Ú¡¼¥¸¤Ï libc5 ¤Ë´ð¤Å¤¤¤Æºî¤é¤ì¤Æ¤¤¤Æ¡¢
ºÇ¿·¤Î¤â¤Î¤Ç¤Ï°ã¤Ã¤Æ¤¤¤ë¤«¤â¤·¤ì¤Ê¤¤¡£
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR ac (1),
.BR date (1),
.BR last (1),
.BR login (1),
.BR who (1),
.BR getutent (3),
.BR getutmp (3),
.BR login (3),
.BR logout (3),
.BR logwtmp (3),
.BR updwtmp (3),
.BR init (8)