bsd/man/man2/reboot.2

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  35 .\"     @(#)reboot.2    8.1 (Berkeley) 6/4/93
  36 .\"
  37 .Dd June 4, 1993
  38 .Dt REBOOT 2
  39 .Os BSD 4
  40 .Sh NAME
  41 .Nm reboot
  42 .Nd reboot system or halt processor
  43 .Sh SYNOPSIS
  44 .Fd #include <unistd.h>
  45 .Fd #include <sys/reboot.h>
  46 .Ft int
  47 .Fn reboot "int howto"
  48 .Sh DESCRIPTION
  49 .Fn Reboot
  50 reboots the system.
  51 Only the super-user may reboot a machine on demand.
  52 However, a reboot is invoked
  53 automatically in the event of unrecoverable system failures.
  54 .Pp
  55 .Fa Howto
  56 is a mask of options; the system call interface allows the following
  57 options, defined in the include file
  58 .Aq Pa sys/reboot.h ,
  59 to be passed
  60 to the new kernel or the new bootstrap and init programs.
  61 .Bl -tag -width RB_INITNAMEA
  62 .It Dv RB_AUTOBOOT
  63 The default, causing the system to reboot in its usual fashion.
  64 .It Dv RB_ASKNAME
  65 Interpreted by the bootstrap program itself, causing it to
  66 prompt on the console as to what file should be booted.
  67 Normally, the system is booted from the file
  68 .Dq Em xx Ns No (0,0)bsd ,
  69 where
  70 .Em xx
  71 is the default disk name,
  72 without prompting for the file name.
  73 .It Dv RB_DFLTROOT
  74 Use the compiled in root device.
  75 Normally, the system uses the device from which it was booted
  76 as the root device if possible.
  77 (The default behavior is dependent on the ability of the bootstrap program
  78 to determine the drive from which it was loaded, which is not possible
  79 on all systems.)
  80 .It Dv RB_DUMP
  81 Dump kernel memory before rebooting; see
  82 .Xr savecore 8
  83 for more information.
  84 .It Dv RB_HALT
  85 the processor is simply halted; no reboot takes place.
  86 This option should be used with caution.
  87 .It Dv RB_INITNAME
  88 An option allowing the specification of an init program (see
  89 .Xr init 8 )
  90 other than
  91 .Pa /sbin/init
  92 to be run when the system reboots.
  93 This switch is not currently available.
  94 .It Dv RB_KDB
  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
  97 for debugging.
  98 Several other options have different meaning if combined
  99 with this option, although their use may not be possible
 100 via the
 101 .Fn reboot
 102 call.
 103 See
 104 .Xr kadb 4
 105 for more information.
 106 .It Dv RB_NOSYNC
 107 Normally, the disks are sync'd (see
 108 .Xr sync 8 )
 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.
 112 .It Dv RB_RDONLY
 113 Initially mount the root file system read-only.
 114 This is currently the default, and this option has been deprecated.
 115 .It Dv RB_SINGLE
 116 Normally, the reboot procedure involves an automatic disk consistency
 117 check and then multi-user operations.
 118 .Dv RB_SINGLE
 119 prevents this, booting the system with a single-user shell
 120 on the console.
 121 .Dv RB_SINGLE
 122 is actually interpreted by the
 123 .Xr init 8
 124 program in the newly booted system.
 125 .Pp
 126 When no options are given (i.e.,
 127 .Dv RB_AUTOBOOT
 128 is used), the system is
 129 rebooted from file ``bsd'' in the root file system of unit 0
 130 of a disk chosen in a processor specific way.
 131 An automatic consistency check of the disks is normally performed
 132 (see
 133 .Xr fsck 8 ) .
 134 .El
 135 .Sh RETURN VALUES
 136 If successful, this call never returns.
 137 Otherwise, a -1 is returned and an error is returned in the global
 138 variable
 139 .Va errno .
 140 .Sh ERRORS
 141 .Bl -tag -width Er
 142 .It Bq Er EPERM
 143 The caller is not the super-user.
 144 .El
 145 .Sh SEE ALSO
 146 .Xr kadb 4 ,
 147 .Xr crash 8 ,
 148 .Xr halt 8 ,
 149 .Xr init 8 ,
 150 .Xr reboot 8 ,
 151 .Xr savecore 8
 152 .Sh BUGS
 153 The HP300 implementation supports neither
 154 .Dv RB_DFLTROOT
 155 nor
 156 .Dv RB_KDB .
 157 .Sh HISTORY
 158 The
 159 .Fn reboot
 160 function call appeared in
 161 .Bx 4.0 .