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