1 .\" Copyright (c) 1980, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
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 .\" 3. Neither the name of the University nor the names of its contributors
13 .\" may be used to endorse or promote products derived from this software
14 .\" without specific prior written permission.
16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 .\" @(#)reboot.2 8.1 (Berkeley) 6/4/93
29 .\" $FreeBSD: src/lib/libc/sys/reboot.2,v 1.9.2.4 2001/12/14 18:34:01 ru Exp $
36 .Nd reboot system or halt processor
43 .Fn reboot "int howto"
47 Only the super-user may reboot a machine on demand.
48 However, a reboot is invoked
49 automatically in the event of unrecoverable system failures.
52 is a mask of options; the system call interface allows the following
53 options, defined in the include file
56 to the new kernel or the new bootstrap and init programs.
57 .Bl -tag -width RB_INITNAMEA
59 The default, causing the system to reboot in its usual fashion.
61 Interpreted by the bootstrap program itself, causing it to
62 prompt on the console as to what file should be booted.
63 Normally, the system is booted from the file
64 .Dq Em xx Ns No (0,0)kernel ,
67 is the default disk name,
68 without prompting for the file name.
70 Use the compiled in root device.
71 Normally, the system uses the device from which it was booted
72 as the root device if possible.
73 (The default behavior is dependent on the ability of the bootstrap program
74 to determine the drive from which it was loaded, which is not possible
77 Dump kernel memory before rebooting; see
81 the processor is simply halted; no reboot takes place.
82 This option should be used with caution.
84 After halting, the shutdown code will do what it can to turn
86 This requires hardware support.
88 An option allowing the specification of an init program (see
92 to be run when the system reboots.
93 This switch is not currently available.
95 Load the symbol table and enable a built-in debugger in the system.
96 This option will have no useful function if the kernel is not configured
98 Several other options have different meaning if combined
99 with this option, although their use may not be possible
105 for more information.
107 Normally, the disks are sync'd (see
109 before the processor is halted or rebooted.
110 This option may be useful if file system changes have been made manually
111 or if the processor is on fire.
113 Initially mount the root file system read-only.
114 This is currently the default, and this option has been deprecated.
116 Normally, the reboot procedure involves an automatic disk consistency
117 check and then multi-user operations.
119 prevents this, booting the system with a single-user shell
122 is actually interpreted by the
124 program in the newly booted system.
127 When no options are given (i.e.,
129 is used), the system is
132 in the root file system of unit 0
133 of a disk chosen in a processor specific way.
134 An automatic consistency check of the disks is normally performed
138 If successful, this call never returns.
139 Otherwise, a -1 is returned and an error is returned in the global
145 The caller is not the super-user.
156 function call appeared in