276da39af9
Approved by: roberto, delphij Security: VuXML: 0d0f3050-1f69-11e5-9ba9-d050996490d0 Security: http://bugs.ntp.org/show_bug.cgi?id=2853 Security: https://www.kb.cert.org/vuls/id/668167 Security: http://support.ntp.org/bin/view/Main/SecurityNotice#June_2015_NTP_Security_Vulnerabi
209 lines
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209 lines
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<title>Ntp-wait User's Manual</title>
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<h1 class="settitle">Ntp-wait User's Manual</h1>
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<div class="node">
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<p><hr>
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<a name="Top"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Description">ntp-wait Description</a>,
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Previous: <a rel="previous" accesskey="p" href="#dir">(dir)</a>,
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Up: <a rel="up" accesskey="u" href="#dir">(dir)</a>
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<br>
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</div>
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<p>This document describes the use of the NTP Project's <code>ntp-wait</code> program.
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<p>If there are time-sensitive applications,
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the proper sequence of events is to
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run <code>ntpd -g</code> as early as possible,
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then invoke all of the non-time-sensitive process,
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run <code>ntp-wait</code> to block
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until the system's time has stabilized and synchronized,
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and only then start any applicaitons (like database servers) that require
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accurate and stable time.
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<p>This document applies to version 4.2.8p3 of <code>ntp-wait</code>.
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<div class="shortcontents">
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<h2>Short Contents</h2>
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<ul>
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</ul>
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</div>
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<ul class="menu">
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<li><a accesskey="1" href="#ntp_002dwait-Description">ntp-wait Description</a>: Description
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<li><a accesskey="2" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>: Invoking ntp-wait
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</ul>
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<div class="node">
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<p><hr>
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<a name="ntp_002dwait-Invocation"></a>
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<br>
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</div>
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<h3 class="section">0.1 Invoking ntp-wait</h3>
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<p><a name="index-ntp_002dwait-1"></a><a name="index-Wait-for-ntpd-to-stabilize-the-system-clock-2"></a>
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<p><code>ntp-wait</code>
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will send at most
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<kbd>num-tries</kbd>
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queries to
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<code>ntpd(8)</code>,
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sleeping for
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<kbd>secs-between-tries</kbd>
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after each status return that says
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<code>ntpd(8)</code>
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has not yet produced a synchronized and stable system clock.
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<p><code>ntp-wait</code>
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will do this quietly, unless the
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<code>-v</code>
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flag is provided.
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This can be useful at boot time, to delay the boot sequence until after
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<kbd>ntpd</kbd> <kbd>-g</kbd>
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has set the time.
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<p>This section was generated by <strong>AutoGen</strong>,
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using the <code>agtexi-cmd</code> template and the option descriptions for the <code>ntp-wait</code> program.
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<ul class="menu">
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<li><a accesskey="1" href="#ntp_002dwait-usage">ntp-wait usage</a>: ntp-wait help/usage (<span class="option">--help</span>)
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<li><a accesskey="2" href="#ntp_002dwait-tries">ntp-wait tries</a>: tries option (-n)
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<li><a accesskey="3" href="#ntp_002dwait-sleep">ntp-wait sleep</a>: sleep option (-s)
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<li><a accesskey="4" href="#ntp_002dwait-verbose">ntp-wait verbose</a>: verbose option (-v)
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<li><a accesskey="5" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>: exit status
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<li><a accesskey="6" href="#ntp_002dwait-Authors">ntp-wait Authors</a>: Authors
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<li><a accesskey="7" href="#ntp_002dwait-Notes">ntp-wait Notes</a>: Notes
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</ul>
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<div class="node">
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<p><hr>
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<a name="ntp_002dwait-usage"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-tries">ntp-wait tries</a>,
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Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>
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<br>
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</div>
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<h4 class="subsection">0.1.1 ntp-wait help/usage (<span class="option">--help</span>)</h4>
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<p><a name="index-ntp_002dwait-help-3"></a>
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This is the automatically generated usage text for ntp-wait.
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<p>The text printed is the same whether selected with the <code>help</code> option
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(<span class="option">--help</span>) or the <code>more-help</code> option (<span class="option">--more-help</span>). <code>more-help</code> will print
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the usage text by passing it through a pager program.
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<code>more-help</code> is disabled on platforms without a working
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<code>fork(2)</code> function. The <code>PAGER</code> environment variable is
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used to select the program, defaulting to <span class="file">more</span>. Both will exit
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with a status code of 0.
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<pre class="example">ntp-wait - Wait for ntpd to stabilize the system clock - Ver. 4.2.8p3
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USAGE: ntp-wait [ -<flag> [<val>] | --<name>[{=| }<val>] ]...
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-n, --tries=num Number of times to check ntpd
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-s, --sleep=num How long to sleep between tries
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-v, --verbose Be verbose
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-?, --help Display usage information and exit
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--more-help Pass the extended usage text through a pager
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Options are specified by doubled hyphens and their name or by a single
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hyphen and the flag character.
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</pre>
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<div class="node">
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<p><hr>
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<a name="ntp_002dwait-tries"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-sleep">ntp-wait sleep</a>,
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Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-usage">ntp-wait usage</a>,
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Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>
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<br>
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</div>
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<h4 class="subsection">0.1.2 tries option (-n)</h4>
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<p><a name="index-ntp_002dwait_002dtries-4"></a>
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This is the “number of times to check ntpd” option.
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This option takes a number argument.
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The maximum number of times we will check <code>ntpd</code> to see if
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it has been able to synchronize and stabilize the system clock.
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<div class="node">
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<p><hr>
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<a name="ntp_002dwait-sleep"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-verbose">ntp-wait verbose</a>,
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Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-tries">ntp-wait tries</a>,
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Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>
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<br>
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</div>
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<h4 class="subsection">0.1.3 sleep option (-s)</h4>
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<p><a name="index-ntp_002dwait_002dsleep-5"></a>
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This is the “how long to sleep between tries” option.
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This option takes a number argument <span class="file">secs-between-tries</span>.
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We will sleep for <span class="file">secs-between-tries</span> after each query
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of <code>ntpd</code> that returns "the time is not yet stable".
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<div class="node">
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<p><hr>
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<a name="ntp_002dwait-verbose"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>,
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Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-sleep">ntp-wait sleep</a>,
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Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>
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<br>
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</div>
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<h4 class="subsection">0.1.4 verbose option (-v)</h4>
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<p><a name="index-ntp_002dwait_002dverbose-6"></a>
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This is the “be verbose” option.
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By default, <code>ntp-wait</code> is silent.
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With this option, <code>ntp-wait</code> will provide status information.
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<div class="node">
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<p><hr>
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<a name="ntp_002dwait-exit-status"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Authors">ntp-wait Authors</a>,
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Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-verbose">ntp-wait verbose</a>,
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Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>
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<br>
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</div>
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<h4 class="subsection">0.1.5 ntp-wait exit status</h4>
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<p>One of the following exit values will be returned:
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<dl>
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<dt><span class="samp">0 (EXIT_SUCCESS)</span><dd>Successful program execution.
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<br><dt><span class="samp">1 (EXIT_FAILURE)</span><dd>The operation failed or the command syntax was not valid.
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</dl>
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<div class="node">
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<p><hr>
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<a name="ntp_002dwait-Authors"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Notes">ntp-wait Notes</a>,
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Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>,
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Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>
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<br>
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</div>
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<h4 class="subsection">0.1.6 ntp-wait Authors</h4>
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<div class="node">
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<p><hr>
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<a name="ntp_002dwait-Notes"></a>Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-Authors">ntp-wait Authors</a>,
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Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>
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<br>
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</div>
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<h4 class="subsection">0.1.7 ntp-wait Notes</h4>
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</body></html>
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