| @@ -1,89 +1,89 @@ | | | @@ -1,89 +1,89 @@ |
1 | .\" $NetBSD: swwdog.4,v 1.8 2011/06/08 12:19:14 pgoyette Exp $ | | 1 | .\" $NetBSD: swwdog.4,v 1.9 2015/04/14 10:50:25 pgoyette Exp $ |
2 | .\" | | 2 | .\" |
3 | .\" Copyright (c) 2004, 2005 Steven M. Bellovin | | 3 | .\" Copyright (c) 2004, 2005 Steven M. Bellovin |
4 | .\" All rights reserved. | | 4 | .\" All rights reserved. |
5 | .\" | | 5 | .\" |
6 | .\" Redistribution and use in source and binary forms, with or without | | 6 | .\" Redistribution and use in source and binary forms, with or without |
7 | .\" modification, are permitted provided that the following conditions | | 7 | .\" modification, are permitted provided that the following conditions |
8 | .\" are met: | | 8 | .\" are met: |
9 | .\" 1. Redistributions of source code must retain the above copyright | | 9 | .\" 1. Redistributions of source code must retain the above copyright |
10 | .\" notice, this list of conditions and the following disclaimer. | | 10 | .\" notice, this list of conditions and the following disclaimer. |
11 | .\" 2. Redistributions in binary form must reproduce the above copyright | | 11 | .\" 2. Redistributions in binary form must reproduce the above copyright |
12 | .\" notice, this list of conditions and the following disclaimer in the | | 12 | .\" notice, this list of conditions and the following disclaimer in the |
13 | .\" documentation and/or other materials provided with the distribution. | | 13 | .\" documentation and/or other materials provided with the distribution. |
14 | .\" 3. All advertising materials mentioning features or use of this software | | 14 | .\" 3. All advertising materials mentioning features or use of this software |
15 | .\" must display the following acknowledgement: | | 15 | .\" must display the following acknowledgement: |
16 | .\" This product includes software developed by the NetBSD | | 16 | .\" This product includes software developed by the NetBSD |
17 | .\" Foundation, Inc. and its contributors. | | 17 | .\" Foundation, Inc. and its contributors. |
18 | .\" 4. Neither the name of the author nor the names of its | | 18 | .\" 4. Neither the name of the author nor the names of its |
19 | .\" contributors may be used to endorse or promote products derived | | 19 | .\" contributors may be used to endorse or promote products derived |
20 | .\" from this software without specific prior written permission. | | 20 | .\" from this software without specific prior written permission. |
21 | .\" | | 21 | .\" |
22 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS | | 22 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS |
23 | .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED | | 23 | .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
24 | .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | | 24 | .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
25 | .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS | | 25 | .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS |
26 | .\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | | 26 | .\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
27 | .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | | 27 | .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
28 | .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | | 28 | .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
29 | .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | | 29 | .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
30 | .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | | 30 | .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
31 | .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | | 31 | .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
32 | .\" POSSIBILITY OF SUCH DAMAGE. | | 32 | .\" POSSIBILITY OF SUCH DAMAGE. |
33 | .\" | | 33 | .\" |
34 | .Dd June 8, 2011 | | 34 | .Dd June 8, 2011 |
35 | .\" Written by Steven M. Bellovin | | 35 | .\" Written by Steven M. Bellovin |
36 | .Dt SWWDOG 4 | | 36 | .Dt SWWDOG 4 |
37 | .Os | | 37 | .Os |
38 | .Sh NAME | | 38 | .Sh NAME |
39 | .Nm swwdog | | 39 | .Nm swwdog |
40 | .Nd software watchdog timer | | 40 | .Nd software watchdog timer |
41 | .Sh SYNOPSIS | | 41 | .Sh SYNOPSIS |
42 | .Cd "pseudo-device swwdog" | | 42 | .Cd "pseudo-device swwdog" |
43 | .Sh DESCRIPTION | | 43 | .Sh DESCRIPTION |
44 | The | | 44 | The |
45 | .Nm | | 45 | .Nm |
46 | driver provides a software watchdog timer that works with | | 46 | driver provides a software watchdog timer that works with |
47 | .Xr wdogctl 8 . | | 47 | .Xr wdogctl 8 . |
48 | If the timer expires, the system reboots if the boolean variable | | 48 | If the timer expires, the system reboots if the boolean variable |
49 | .Va swwdog_reboot | | 49 | .Va swwdog_reboot |
50 | is | | 50 | is |
51 | .Dv true ; | | 51 | .Dv true ; |
52 | otherwise, the system will panic. | | 52 | otherwise, the system will panic. |
53 | .Va swwdog_reboot | | 53 | .Va swwdog_reboot |
54 | is accessible as a | | 54 | is accessible as the |
55 | .Xr sysctl 8 | | 55 | .Xr sysctl 8 |
56 | variable, hw.swwdog.reboot and defaults to | | 56 | variable hw.swwdog.reboot and defaults to |
57 | .Dv false . | | 57 | .Dv false . |
58 | .Pp | | 58 | .Pp |
59 | The default period of | | 59 | The default period of |
60 | .Nm | | 60 | .Nm |
61 | is 60 seconds. | | 61 | is 60 seconds. |
62 | .Pp | | 62 | .Pp |
63 | As with other watchdog timers, the | | 63 | As with other watchdog timers, the |
64 | .Nm | | 64 | .Nm |
65 | driver prevents a system from suspending when the watchdog is armed. | | 65 | driver prevents a system from suspending when the watchdog is armed. |
66 | .Sh SEE ALSO | | 66 | .Sh SEE ALSO |
67 | .Xr sysctl 8 , | | 67 | .Xr sysctl 8 , |
68 | .Xr wdogctl 8 | | 68 | .Xr wdogctl 8 |
69 | .Sh HISTORY | | 69 | .Sh HISTORY |
70 | The | | 70 | The |
71 | .Nm | | 71 | .Nm |
72 | driver was written by | | 72 | driver was written by |
73 | .An Steven M. Bellovin . | | 73 | .An Steven M. Bellovin . |
74 | .Sh BUGS | | 74 | .Sh BUGS |
75 | Only one watchdog timer can be active at any given time. | | 75 | Only one watchdog timer can be active at any given time. |
76 | (Arguably, this is a bug in the watchdog timer framework.) | | 76 | (Arguably, this is a bug in the watchdog timer framework.) |
77 | Therefore, only a single instance of the | | 77 | Therefore, only a single instance of the |
78 | .Nm | | 78 | .Nm |
79 | device can be created. | | 79 | device can be created. |
80 | .Pp | | 80 | .Pp |
81 | Kernel tickle mode is useless with | | 81 | Kernel tickle mode is useless with |
82 | .Nm | | 82 | .Nm |
83 | and arguably should be rejected, since both it and | | 83 | and arguably should be rejected, since both it and |
84 | this driver rely on the same callout mechanism; if one is | | 84 | this driver rely on the same callout mechanism; if one is |
85 | blocked, almost certainly the other is as well. | | 85 | blocked, almost certainly the other is as well. |
86 | .Pp | | 86 | .Pp |
87 | The alarm option to | | 87 | The alarm option to |
88 | .Xr wdogctl 8 | | 88 | .Xr wdogctl 8 |
89 | isn't implemented. | | 89 | isn't implemented. |