1.\" Copyright (C) 1993-1998 by Andrey A. Chernov, Moscow, Russia.
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\" notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\" notice, this list of conditions and the following disclaimer in the
11.\" documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
| 1.\" Copyright (C) 1993-1998 by Andrey A. Chernov, Moscow, Russia.
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\" notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\" notice, this list of conditions and the following disclaimer in the
11.\" documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
|
25.\" $FreeBSD: head/sbin/adjkerntz/adjkerntz.8 73233 2001-02-28 17:38:53Z ru $
| 25.\" $FreeBSD: head/sbin/adjkerntz/adjkerntz.8 77577 2001-06-01 10:57:26Z ru $
|
26.\"
27.Dd April 4, 1996
28.Dt ADJKERNTZ 8
29.Os FreeBSD
30.Sh NAME
31.Nm adjkerntz
32.Nd "adjust local time CMOS clock to reflect time zone changes and keep current timezone offset for the kernel"
33.Sh SYNOPSIS
34.Nm
35.Fl i
36.Nm
37.Fl a Op Fl s
38.Sh DESCRIPTION
39.Nm Adjkerntz
40maintains the proper relationship between the kernel clock, which
41is always set to UTC, and the CMOS clock, which may be set to local
42time.
43.Nm Adjkerntz
44also informs the kernel about machine timezone shifts to
45maintain proper timestamps for local time file systems such as the MS-DOS
46file system.
47The main purpose of this thing is not general fixing of
48initially broken MS-DOS file timestamp idea but keeping
49the same timestamps between
50.Fx
51MS-DOS file system
52and MS-DOS operating system installed on the same
53machine.
54If the file
55.Pa /etc/wall_cmos_clock
56exists, it means that CMOS clock keeps local time (MS-DOS and MS-Windows
57compatible mode).
58If that file does not exist, it means that the CMOS clock keeps UTC time.
59.Nm Adjkerntz
60passes this state to the
61.Pa machdep.wall_cmos_clock
62kernel variable.
63.Pp
64Adjustments may be needed at system startup and shutdown, and
65whenever a time zone change occurs.
66To handle these different situations,
67.Nm
68is invoked in two ways:
69.Bl -tag -width 4n
70.It Fl i
71This form handles system startups and shutdowns.
72.Nm Adjkerntz
73is invoked with this option from
74.Pa /etc/rc
75on entry to multi-user mode, before any other daemons have been started.
76.Nm Adjkerntz
77puts itself into the background.
78Then, for a local time CMOS clock,
79.Nm
80reads the local time from it
81and sets the kernel clock to the corresponding UTC time.
82.Nm Adjkerntz
83also stores the local time zone offset into the
84.Pa machdep.adjkerntz
85kernel variable, for use by subsequent invocations of
86.Em "'adjkerntz -a'"
87and by local time file systems.
88.Pp
89For a local time CMOS clock
90.Em "'adjkerntz -i'"
91pauses, and remains inactive as a background daemon until it
92receives a SIGTERM.
93The SIGTERM will normally be sent by
94.Xr init 8
95when the system leaves multi-user mode (usually, because the system
96is being shut down).
97After receiving the SIGTERM,
98.Nm
99reads the UTC kernel clock and updates the CMOS clock, if necessary,
100to ensure that it reflects the current local time zone.
101Then
102.Nm
103exits.
104.It Fl a Op Fl s
105This form is used to update the local time CMOS clock and kernel
106.Pa machdep.adjkerntz
107variable when time zone changes occur,
108e.g., when entering or leaving daylight savings time.
109.Nm Adjkerntz
110uses the kernel clock's UTC time,
111the previously stored
112time zone offset, and the changed time zone rule to
113calculate a new time zone offset.
114It stores the new offset into the
115.Pa machdep.adjkerntz
116kernel variable, and updates the wall CMOS clock to the new local time.
117If
118.Em "'adjkerntz -a'"
119was started at a nonexistent time (during a timezone change), it exits
120with a warning diagnostic unless the
121.Fl s
122option was used, in which case
123.Nm
124sleeps 30 minutes and tries again.
125.Pp
126This form should be invoked from root's
127.Xr crontab 5
128every half hour between midnight and 5am, when most modern time
129zone changes occur.
130Warning: don't use the
131.Fl s
132option in a
133.Xr crontab 5
134command line, or multiple
135.Em "'adjkerntz -a'"
136instances could conflict with each other.
137.El
138.Pp
139.Nm Adjkerntz
140clears the kernel timezone structure and makes the kernel clock run
141in the UTC time zone.
142Super-user privileges are required for all operations.
143.Sh ENVIRONMENT
144.Bl -tag -width Fl
145.It Ev TZ
146Time zone change rule, see
147.Xr tzset 3 ;
148not needed when
149.Xr tzsetup 8
150or
151.Xr zic 8
152is used.
153.El
154.Sh FILES
155.Bl -tag -width /etc/wall_cmos_clock -compact
156.It Pa /etc/localtime
157Current zoneinfo file, see
158.Xr tzsetup 8
159and
160.Xr zic 8 .
161.It Pa /etc/wall_cmos_clock
162Empty file.
163Its presence indicates that the machine's CMOS clock is set to local
164time, while its absence indicates a UTC CMOS clock.
165.El
166.Sh SEE ALSO
167.Xr tzset 3 ,
168.Xr crontab 5 ,
| 26.\"
27.Dd April 4, 1996
28.Dt ADJKERNTZ 8
29.Os FreeBSD
30.Sh NAME
31.Nm adjkerntz
32.Nd "adjust local time CMOS clock to reflect time zone changes and keep current timezone offset for the kernel"
33.Sh SYNOPSIS
34.Nm
35.Fl i
36.Nm
37.Fl a Op Fl s
38.Sh DESCRIPTION
39.Nm Adjkerntz
40maintains the proper relationship between the kernel clock, which
41is always set to UTC, and the CMOS clock, which may be set to local
42time.
43.Nm Adjkerntz
44also informs the kernel about machine timezone shifts to
45maintain proper timestamps for local time file systems such as the MS-DOS
46file system.
47The main purpose of this thing is not general fixing of
48initially broken MS-DOS file timestamp idea but keeping
49the same timestamps between
50.Fx
51MS-DOS file system
52and MS-DOS operating system installed on the same
53machine.
54If the file
55.Pa /etc/wall_cmos_clock
56exists, it means that CMOS clock keeps local time (MS-DOS and MS-Windows
57compatible mode).
58If that file does not exist, it means that the CMOS clock keeps UTC time.
59.Nm Adjkerntz
60passes this state to the
61.Pa machdep.wall_cmos_clock
62kernel variable.
63.Pp
64Adjustments may be needed at system startup and shutdown, and
65whenever a time zone change occurs.
66To handle these different situations,
67.Nm
68is invoked in two ways:
69.Bl -tag -width 4n
70.It Fl i
71This form handles system startups and shutdowns.
72.Nm Adjkerntz
73is invoked with this option from
74.Pa /etc/rc
75on entry to multi-user mode, before any other daemons have been started.
76.Nm Adjkerntz
77puts itself into the background.
78Then, for a local time CMOS clock,
79.Nm
80reads the local time from it
81and sets the kernel clock to the corresponding UTC time.
82.Nm Adjkerntz
83also stores the local time zone offset into the
84.Pa machdep.adjkerntz
85kernel variable, for use by subsequent invocations of
86.Em "'adjkerntz -a'"
87and by local time file systems.
88.Pp
89For a local time CMOS clock
90.Em "'adjkerntz -i'"
91pauses, and remains inactive as a background daemon until it
92receives a SIGTERM.
93The SIGTERM will normally be sent by
94.Xr init 8
95when the system leaves multi-user mode (usually, because the system
96is being shut down).
97After receiving the SIGTERM,
98.Nm
99reads the UTC kernel clock and updates the CMOS clock, if necessary,
100to ensure that it reflects the current local time zone.
101Then
102.Nm
103exits.
104.It Fl a Op Fl s
105This form is used to update the local time CMOS clock and kernel
106.Pa machdep.adjkerntz
107variable when time zone changes occur,
108e.g., when entering or leaving daylight savings time.
109.Nm Adjkerntz
110uses the kernel clock's UTC time,
111the previously stored
112time zone offset, and the changed time zone rule to
113calculate a new time zone offset.
114It stores the new offset into the
115.Pa machdep.adjkerntz
116kernel variable, and updates the wall CMOS clock to the new local time.
117If
118.Em "'adjkerntz -a'"
119was started at a nonexistent time (during a timezone change), it exits
120with a warning diagnostic unless the
121.Fl s
122option was used, in which case
123.Nm
124sleeps 30 minutes and tries again.
125.Pp
126This form should be invoked from root's
127.Xr crontab 5
128every half hour between midnight and 5am, when most modern time
129zone changes occur.
130Warning: don't use the
131.Fl s
132option in a
133.Xr crontab 5
134command line, or multiple
135.Em "'adjkerntz -a'"
136instances could conflict with each other.
137.El
138.Pp
139.Nm Adjkerntz
140clears the kernel timezone structure and makes the kernel clock run
141in the UTC time zone.
142Super-user privileges are required for all operations.
143.Sh ENVIRONMENT
144.Bl -tag -width Fl
145.It Ev TZ
146Time zone change rule, see
147.Xr tzset 3 ;
148not needed when
149.Xr tzsetup 8
150or
151.Xr zic 8
152is used.
153.El
154.Sh FILES
155.Bl -tag -width /etc/wall_cmos_clock -compact
156.It Pa /etc/localtime
157Current zoneinfo file, see
158.Xr tzsetup 8
159and
160.Xr zic 8 .
161.It Pa /etc/wall_cmos_clock
162Empty file.
163Its presence indicates that the machine's CMOS clock is set to local
164time, while its absence indicates a UTC CMOS clock.
165.El
166.Sh SEE ALSO
167.Xr tzset 3 ,
168.Xr crontab 5 ,
|
169.Xr mount_msdos 8 ,
| 169.Xr mount_msdosfs 8 ,
|
170.Xr rc 8 ,
171.Xr sysctl 8 ,
172.Xr tzsetup 8 ,
173.Xr zic 8
174.Sh DIAGNOSTICS
175No diagnostics.
176If an error occurs,
177.Nm
178logs an error message via
179.Xr syslog 3
180and exits with a nonzero return code.
181.Sh AUTHORS
182.An Andrey A. Chernov Aq ache@astral.msk.su
183.Sh HISTORY
184The
185.Nm
186command appeared in
187.Fx 1.0 .
| 170.Xr rc 8 ,
171.Xr sysctl 8 ,
172.Xr tzsetup 8 ,
173.Xr zic 8
174.Sh DIAGNOSTICS
175No diagnostics.
176If an error occurs,
177.Nm
178logs an error message via
179.Xr syslog 3
180and exits with a nonzero return code.
181.Sh AUTHORS
182.An Andrey A. Chernov Aq ache@astral.msk.su
183.Sh HISTORY
184The
185.Nm
186command appeared in
187.Fx 1.0 .
|