Sophie: howto-html-en-20080722-2mdv2010.1 noarch

howto-html-en-20080722-2mdv2010.1.noarch.rpm

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>Adjust behaviour of CtrlAltDelete</TITLE
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><H1
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><A
NAME="SECURITY-CTRLALTDEL"
></A
>9.10. Adjust behaviour of <B
CLASS="KEYCAP"
>Ctrl</B
>-<B
CLASS="KEYCAP"
>Alt</B
>-<B
CLASS="KEYCAP"
>Delete</B
></H1
><P
>The <SPAN
CLASS="PRODUCTNAME"
>IBM PC</SPAN
> used <B
CLASS="KEYCAP"
>Ctrl</B
>-<B
CLASS="KEYCAP"
>Alt</B
>-<B
CLASS="KEYCAP"
>Delete</B
> to launch a reboot of the computer.  Linux traps this
   key chord and makes it available to the
   <SPAN
CLASS="APPLICATION"
>init</SPAN
> system.  This is done by sending
   the <SPAN
CLASS="APPLICATION"
>init</SPAN
> process a
   <TT
CLASS="LITERAL"
>SIGINT</TT
> signal (although <B
CLASS="COMMAND"
>ctrlaltdel
   hard</B
> can undo this trap and make the key chord reboot the
   comptuer immediately).  The <SPAN
CLASS="APPLICATION"
>init</SPAN
> system
   uses <TT
CLASS="FILENAME"
>/etc/inittab</TT
> to determine how to handle
   the signal generated by the <B
CLASS="KEYCAP"
>Ctrl</B
>-<B
CLASS="KEYCAP"
>Alt</B
>-<B
CLASS="KEYCAP"
>Delete</B
> key
   chord.</P
><P
>Most distributions cleanly reboot the system, mimicing the
   behaviour that most users expect.  <A
HREF="security-ctrlaltdel.html#SECURITY-CTRLALTDEL-TELINIT-DEFAULT"
>Figure 9-14</A
> shows how this is
   done.</P
><DIV
CLASS="FIGURE"
><A
NAME="SECURITY-CTRLALTDEL-TELINIT-DEFAULT"
></A
><P
><B
>Figure 9-14. Default handling of <B
CLASS="KEYCAP"
>Ctrl</B
>-<B
CLASS="KEYCAP"
>Alt</B
>-<B
CLASS="KEYCAP"
>Delete</B
> in
    <TT
CLASS="FILENAME"
>/etc/inittab</TT
></B
></P
><TABLE
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><TD
><FONT
COLOR="#000000"
><PRE
CLASS="PROGRAMLISTING"
># Trap CTRL-ALT-DELETE
ca::ctrlaltdel:/sbin/shutdown -t3 -r now</PRE
></FONT
></TD
></TR
></TABLE
></DIV
><P
>Depending upon each individual site you may wish to disable
   <B
CLASS="KEYCAP"
>Ctrl</B
>-<B
CLASS="KEYCAP"
>Alt</B
>-<B
CLASS="KEYCAP"
>Delete</B
>.  This is shown in <A
HREF="security-ctrlaltdel.html#SECURITY-CTRLALTDEL-TELINIT-IGNORE"
>Figure 9-15</A
>.</P
><DIV
CLASS="FIGURE"
><A
NAME="SECURITY-CTRLALTDEL-TELINIT-IGNORE"
></A
><P
><B
>Figure 9-15. Ignoring <B
CLASS="KEYCAP"
>Ctrl</B
>-<B
CLASS="KEYCAP"
>Alt</B
>-<B
CLASS="KEYCAP"
>Delete</B
> in
    <TT
CLASS="FILENAME"
>/etc/inittab</TT
></B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
WIDTH="100%"
><TR
><TD
><FONT
COLOR="#000000"
><PRE
CLASS="PROGRAMLISTING"
># Trap CTRL-ALT-DELETE and do nothing
ca::ctrlaltdel:</PRE
></FONT
></TD
></TR
></TABLE
></DIV
><P
>Alternatively, you may wish to cleanly shut down the
   computer.  This is very easy to explain to operators and
   instructions can be displayed on the monitor using
   <TT
CLASS="FILENAME"
>/etc/issue</TT
> or a <SPAN
CLASS="PRODUCTNAME"
>Post-it
   Note</SPAN
>.  If the computer uses <SPAN
CLASS="PRODUCTNAME"
>Advanced
   Power Management</SPAN
> (or <SPAN
CLASS="ACRONYM"
>APM</SPAN
>) then
   shutting down the computer will also remove the power.</P
><DIV
CLASS="FIGURE"
><A
NAME="SECURITY-CTRLALTDEL-TELINIT-HALT"
></A
><P
><B
>Figure 9-16. Shut down cleanly upon  <B
CLASS="KEYCAP"
>Ctrl</B
>-<B
CLASS="KEYCAP"
>Alt</B
>-<B
CLASS="KEYCAP"
>Delete</B
> in
    <TT
CLASS="FILENAME"
>/etc/inittab</TT
></B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
WIDTH="100%"
><TR
><TD
><FONT
COLOR="#000000"
><PRE
CLASS="PROGRAMLISTING"
># Trap CTRL-ALT-DELETE and shut down
ca::ctrlaltdel:/sbin/shutdown -t3 -h now</PRE
></FONT
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