update-leap.html revision 330106
1<html lang="en"> 2<head> 3<title>update-leap User's Manual</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="update-leap User's Manual"> 6<meta name="generator" content="makeinfo 4.7"> 7<link title="Top" rel="top" href="#Top"> 8<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 9<meta http-equiv="Content-Style-Type" content="text/css"> 10<style type="text/css"><!-- 11 pre.display { font-family:inherit } 12 pre.format { font-family:inherit } 13 pre.smalldisplay { font-family:inherit; font-size:smaller } 14 pre.smallformat { font-family:inherit; font-size:smaller } 15 pre.smallexample { font-size:smaller } 16 pre.smalllisp { font-size:smaller } 17 span.sc { font-variant:small-caps } 18 span.roman { font-family: serif; font-weight: normal; } 19--></style> 20</head> 21<body> 22<h1 class="settitle">update-leap User's Manual</h1> 23<div class="node"> 24<p><hr> 25<a name="Top"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-Description">update-leap Description</a>, 26Previous: <a rel="previous" accesskey="p" href="#dir">(dir)</a>, 27Up: <a rel="up" accesskey="u" href="#dir">(dir)</a> 28<br> 29</div> 30 31 <p>This document describes the use of the NTP Project's <code>update-leap</code> program. 32 33 <p>This document applies to version 4.2.8p11 of <code>update-leap</code>. 34 35<div class="shortcontents"> 36<h2>Short Contents</h2> 37<ul> 38</ul> 39</div> 40 41<ul class="menu"> 42<li><a accesskey="1" href="#update_002dleap-Description">update-leap Description</a>: Description 43<li><a accesskey="2" href="#update_002dleap-Invocation">update-leap Invocation</a>: Invoking update-leap 44</ul> 45 46<div class="node"> 47<p><hr> 48<a name="update_002dleap-Invocation"></a> 49<br> 50</div> 51 52<h3 class="section">0.1 Invoking update-leap</h3> 53 54<p><a name="index-update_002dleap-1"></a><a name="index-leap_002dseconds-file-manager_002fupdater-2"></a> 55 56 <p><code>update-leap</code> 57will validate the file currently on the local system 58and if necessary, updates leap-second definition file. 59 60 <p>Ordinarily, the file is found using the "leapfile" directive in 61<code>ntp.conf(5)</code>. 62However, an alternate location can be specified on the command line. 63 64 <p>If the file does not exist, is not valid, has expired, or is expiring soon, 65a new copy will be downloaded. If the new copy validates, it is installed and 66NTP is (optionally) restarted. 67 68 <p>If the current file is acceptable, no download or restart occurs. 69 70 <p>-c can also be used to invoke another script to perform administrative 71functions, e.g. to copy the file to other local systems. 72.PP 73This can be run as a cron job. As the file is rarely updated, and leap 74seconds are announced at least one month in advance (usually longer), it 75need not be run more frequently than about once every three weeks. 76.PP 77For cron-friendly behavior, define CRONJOB=1 in the crontab. 78.PP 79This script depends on$REQUIREDCMDS 80 81 <p>This section was generated by <strong>AutoGen</strong>, 82using the <code>agtexi-cmd</code> template and the option descriptions for the <code>update-leap</code> program. 83 84<ul class="menu"> 85<li><a accesskey="1" href="#update_002dleap-usage">update-leap usage</a>: update-leap help/usage (<span class="option">--help</span>) 86<li><a accesskey="2" href="#update_002dleap-source_002durl">update-leap source-url</a>: source-url option (-s) 87<li><a accesskey="3" href="#update_002dleap-ipv4">update-leap ipv4</a>: ipv4 option (-4) 88<li><a accesskey="4" href="#update_002dleap-destination">update-leap destination</a>: destination option (-d) 89<li><a accesskey="5" href="#update_002dleap-expiration">update-leap expiration</a>: expiration option (-e) 90<li><a accesskey="6" href="#update_002dleap-ntp_002dconf_002dfile">update-leap ntp-conf-file</a>: ntp-conf-file option (-f) 91<li><a accesskey="7" href="#update_002dleap-force_002dupdate">update-leap force-update</a>: force-update option (-F) 92<li><a accesskey="8" href="#update_002dleap-exit-status">update-leap exit status</a>: exit status 93<li><a accesskey="9" href="#update_002dleap-Usage">update-leap Usage</a>: Usage 94<li><a href="#update_002dleap-Authors">update-leap Authors</a>: Authors 95</ul> 96 97<div class="node"> 98<p><hr> 99<a name="update_002dleap-usage"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-source_002durl">update-leap source-url</a>, 100Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 101<br> 102</div> 103 104<h4 class="subsection">0.1.1 update-leap help/usage (<span class="option">--help</span>)</h4> 105 106<p><a name="index-update_002dleap-help-3"></a> 107This is the automatically generated usage text for update-leap. 108 109 <p>The text printed is the same whether selected with the <code>help</code> option 110(<span class="option">--help</span>) or the <code>more-help</code> option (<span class="option">--more-help</span>). <code>more-help</code> will print 111the usage text by passing it through a pager program. 112<code>more-help</code> is disabled on platforms without a working 113<code>fork(2)</code> function. The <code>PAGER</code> environment variable is 114used to select the program, defaulting to <span class="file">more</span>. Both will exit 115with a status code of 0. 116 117<pre class="example"> 118</pre> 119 <div class="node"> 120<p><hr> 121<a name="update_002dleap-source_002durl"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-ipv4">update-leap ipv4</a>, 122Previous: <a rel="previous" accesskey="p" href="#update_002dleap-usage">update-leap usage</a>, 123Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 124<br> 125</div> 126 127<h4 class="subsection">0.1.2 source-url option (-s)</h4> 128 129<p><a name="index-update_002dleap_002dsource_002durl-4"></a> 130This is the “the url of the master copy of the leapseconds file” option. 131This option takes a string argument. 132Specify the URL of the master copy to download 133$LEAPSRC 134<div class="node"> 135<p><hr> 136<a name="update_002dleap-ipv4"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-destination">update-leap destination</a>, 137Previous: <a rel="previous" accesskey="p" href="#update_002dleap-source_002durl">update-leap source-url</a>, 138Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 139<br> 140</div> 141 142<h4 class="subsection">0.1.3 ipv4 option (-4)</h4> 143 144<p><a name="index-update_002dleap_002dipv4-5"></a> 145This is the “use only ipv4 addresses for dns name resolution” option. 146 147<p class="noindent">This option has some usage constraints. It: 148 <ul> 149<li>must not appear in combination with any of the following options: 150ipv6. 151</ul> 152 153 <p>Force DNS resolution of following host names on the command line 154 to the IPv4 namespace. 155 _EndOfDoc_; 156; 157 158 <p>flag = 159 name = ipv6; 160 flags-cant = ipv4, prefer; 161 value = 6; 162 descrip = "Use only IPv6 addresses for DNS name resolution"; 163 doc = <<- _EndOfDoc_ 164 Force DNS resolution of following host names on the command line 165 to the IPv6 namespace. 166 _EndOfDoc_; 167; 168 169 <p>flag = 170 name = prefer; 171 flags-cant = ipv4, ipv6; 172 value = p; 173 arg-type = keyword; 174 keyword = 4, 6; 175 descrip = 'Prefer IPv4 or IPv6 (as specified) addresses, but use either'; 176 doc = <<- _EndOfDoc_ 177Prefer IPv4 or IPv6 (as specified) addresses, but use either. 178<div class="node"> 179<p><hr> 180<a name="update_002dleap-destination"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-expiration">update-leap expiration</a>, 181Previous: <a rel="previous" accesskey="p" href="#update_002dleap-ipv4">update-leap ipv4</a>, 182Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 183<br> 184</div> 185 186<h4 class="subsection">0.1.4 destination option (-d)</h4> 187 188<p><a name="index-update_002dleap_002ddestination-6"></a> 189This is the “filename on the local system” option. 190This option takes a string argument <span class="file">float</span>. 191The name to use to store the leapfile on the local system. 192$LEAPFILE 193<div class="node"> 194<p><hr> 195<a name="update_002dleap-expiration"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-ntp_002dconf_002dfile">update-leap ntp-conf-file</a>, 196Previous: <a rel="previous" accesskey="p" href="#update_002dleap-destination">update-leap destination</a>, 197Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 198<br> 199</div> 200 201<h4 class="subsection">0.1.5 expiration option (-e)</h4> 202 203<p><a name="index-update_002dleap_002dexpiration-7"></a> 204This is the “refresh the leapfile this long before it expires” option. 205This option takes a string argument. 206Specify how long before expiration the file is to be refreshed 207Units are required, e.g. "-e 60 days" Note that larger values 208imply more frequent refreshes. 209"$PREFETCH" 210<div class="node"> 211<p><hr> 212<a name="update_002dleap-ntp_002dconf_002dfile"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-force_002dupdate">update-leap force-update</a>, 213Previous: <a rel="previous" accesskey="p" href="#update_002dleap-expiration">update-leap expiration</a>, 214Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 215<br> 216</div> 217 218<h4 class="subsection">0.1.6 ntp-conf-file option (-f)</h4> 219 220<p><a name="index-update_002dleap_002dntp_002dconf_002dfile-8"></a> 221This is the “location of the ntp.conf file” option. 222This option takes a string argument. 223Specify location of ntp.conf (used to make sure leapfile directive is 224present and to default leapfile) 225/etc/ntp.conf 226<div class="node"> 227<p><hr> 228<a name="update_002dleap-force_002dupdate"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-exit-status">update-leap exit status</a>, 229Previous: <a rel="previous" accesskey="p" href="#update_002dleap-ntp_002dconf_002dfile">update-leap ntp-conf-file</a>, 230Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 231<br> 232</div> 233 234<h4 class="subsection">0.1.7 force-update option (-F)</h4> 235 236<p><a name="index-update_002dleap_002dforce_002dupdate-9"></a> 237This is the “force update of the leapfile” option. 238Force update even if current file is OK and not close to expiring. 239<div class="node"> 240<p><hr> 241<a name="update_002dleap-exit-status"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-Usage">update-leap Usage</a>, 242Previous: <a rel="previous" accesskey="p" href="#update_002dleap-force_002dupdate">update-leap force-update</a>, 243Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 244<br> 245</div> 246 247<h4 class="subsection">0.1.8 update-leap exit status</h4> 248 249<p>One of the following exit values will be returned: 250 <dl> 251<dt><span class="samp">0 (EXIT_SUCCESS)</span><dd>Successful program execution. 252<br><dt><span class="samp">1 (EXIT_FAILURE)</span><dd>The operation failed or the command syntax was not valid. 253</dl> 254 <div class="node"> 255<p><hr> 256<a name="update_002dleap-Usage"></a>Next: <a rel="next" accesskey="n" href="#update_002dleap-Authors">update-leap Authors</a>, 257Previous: <a rel="previous" accesskey="p" href="#update_002dleap-exit-status">update-leap exit status</a>, 258Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 259<br> 260</div> 261 262<h4 class="subsection">0.1.9 update-leap Usage</h4> 263 264<div class="node"> 265<p><hr> 266<a name="update_002dleap-Authors"></a>Previous: <a rel="previous" accesskey="p" href="#update_002dleap-Usage">update-leap Usage</a>, 267Up: <a rel="up" accesskey="u" href="#update_002dleap-Invocation">update-leap Invocation</a> 268<br> 269</div> 270 271<h4 class="subsection">0.1.10 update-leap Authors</h4> 272 273</body></html> 274 275