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<h1>SignalHandler.cc</h1> </div>
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<a href="SignalHandler_8cc.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001
<a name="l00002"></a>00002 <span class="comment">// -*- mode: c++; c-basic-offset:4 -*-</span>
<a name="l00003"></a>00003
<a name="l00004"></a>00004 <span class="comment">// This file is part of libdap, A C++ implementation of the OPeNDAP Data</span>
<a name="l00005"></a>00005 <span class="comment">// Access Protocol.</span>
<a name="l00006"></a>00006
<a name="l00007"></a>00007 <span class="comment">// Copyright (c) 2002,2003 OPeNDAP, Inc.</span>
<a name="l00008"></a>00008 <span class="comment">// Author: James Gallagher <jgallagher@opendap.org></span>
<a name="l00009"></a>00009 <span class="comment">//</span>
<a name="l00010"></a>00010 <span class="comment">// This library is free software; you can redistribute it and/or</span>
<a name="l00011"></a>00011 <span class="comment">// modify it under the terms of the GNU Lesser General Public</span>
<a name="l00012"></a>00012 <span class="comment">// License as published by the Free Software Foundation; either</span>
<a name="l00013"></a>00013 <span class="comment">// version 2.1 of the License, or (at your option) any later version.</span>
<a name="l00014"></a>00014 <span class="comment">//</span>
<a name="l00015"></a>00015 <span class="comment">// This library is distributed in the hope that it will be useful,</span>
<a name="l00016"></a>00016 <span class="comment">// but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<a name="l00017"></a>00017 <span class="comment">// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</span>
<a name="l00018"></a>00018 <span class="comment">// Lesser General Public License for more details.</span>
<a name="l00019"></a>00019 <span class="comment">//</span>
<a name="l00020"></a>00020 <span class="comment">// You should have received a copy of the GNU Lesser General Public</span>
<a name="l00021"></a>00021 <span class="comment">// License along with this library; if not, write to the Free Software</span>
<a name="l00022"></a>00022 <span class="comment">// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</span>
<a name="l00023"></a>00023 <span class="comment">//</span>
<a name="l00024"></a>00024 <span class="comment">// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.</span>
<a name="l00025"></a>00025
<a name="l00026"></a>00026 <span class="comment">// (c) COPYRIGHT URI/MIT 1994-2002</span>
<a name="l00027"></a>00027 <span class="comment">// Please read the full copyright statement in the file COPYRIGHT_URI.</span>
<a name="l00028"></a>00028 <span class="comment">//</span>
<a name="l00029"></a>00029 <span class="comment">// Authors:</span>
<a name="l00030"></a>00030 <span class="comment">// jhrg,jimg James Gallagher <jgallagher@gso.uri.edu></span>
<a name="l00031"></a>00031
<a name="l00032"></a>00032 <span class="preprocessor">#include "<a class="code" href="config_8h.html">config.h</a>"</span>
<a name="l00033"></a>00033
<a name="l00034"></a>00034 <span class="keyword">static</span> <span class="keywordtype">char</span> rcsid[] <a class="code" href="config_8h.html#a05e109ec893d0b12023d5b0cf4f718c4">not_used</a> =
<a name="l00035"></a>00035 { <span class="stringliteral">"$Id: SignalHandler.cc 22703 2010-05-11 18:10:01Z jimg $"</span>
<a name="l00036"></a>00036 };
<a name="l00037"></a>00037
<a name="l00038"></a>00038 <span class="preprocessor">#include <cstdlib></span>
<a name="l00039"></a>00039
<a name="l00040"></a>00040 <span class="preprocessor">#include <signal.h></span>
<a name="l00041"></a>00041 <span class="preprocessor">#include <pthread.h></span>
<a name="l00042"></a>00042
<a name="l00043"></a>00043 <span class="preprocessor">#ifdef HAVE_UNISTD_H</span>
<a name="l00044"></a>00044 <span class="preprocessor"></span><span class="preprocessor">#include <unistd.h></span> <span class="comment">//for _exit</span>
<a name="l00045"></a>00045 <span class="preprocessor">#endif</span>
<a name="l00046"></a>00046 <span class="preprocessor"></span>
<a name="l00047"></a>00047 <span class="preprocessor">#include "<a class="code" href="SignalHandler_8h.html">SignalHandler.h</a>"</span>
<a name="l00048"></a>00048 <span class="preprocessor">#include "<a class="code" href="util_8h.html">util.h</a>"</span>
<a name="l00049"></a>00049
<a name="l00050"></a>00050 <span class="keyword">namespace </span>libdap {
<a name="l00051"></a>00051
<a name="l00052"></a>00052 EventHandler *SignalHandler::d_signal_handlers[NSIG];
<a name="l00053"></a>00053 <a class="code" href="namespacelibdap.html#aa9d529378270ad490952b2b3352935ed">Sigfunc</a> *SignalHandler::d_old_handlers[NSIG];
<a name="l00054"></a>00054 SignalHandler *SignalHandler::d_instance = 0;
<a name="l00055"></a>00055
<a name="l00056"></a>00056 <span class="comment">// instance_control is used to ensure that in a MT environment d_instance is</span>
<a name="l00057"></a>00057 <span class="comment">// correctly initialized.</span>
<a name="l00058"></a>00058 <span class="keyword">static</span> pthread_once_t instance_control = PTHREAD_ONCE_INIT;
<a name="l00059"></a>00059
<a name="l00061"></a>00061 <span class="keywordtype">void</span>
<a name="l00062"></a>00062 SignalHandler::initialize_instance()
<a name="l00063"></a>00063 {
<a name="l00064"></a>00064 <span class="comment">// MT-Safe if called via pthread_once or similar</span>
<a name="l00065"></a>00065 SignalHandler::d_instance = <span class="keyword">new</span> SignalHandler;
<a name="l00066"></a>00066 atexit(SignalHandler::delete_instance);
<a name="l00067"></a>00067 }
<a name="l00068"></a>00068
<a name="l00070"></a>00070 <span class="keywordtype">void</span>
<a name="l00071"></a>00071 SignalHandler::delete_instance()
<a name="l00072"></a>00072 {
<a name="l00073"></a>00073 <span class="keywordflow">if</span> (SignalHandler::d_instance) {
<a name="l00074"></a>00074 <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 0; i < NSIG; ++i) {
<a name="l00075"></a>00075 <span class="comment">// Fortify warns about a leak because the EventHandler objects</span>
<a name="l00076"></a>00076 <span class="comment">// are not deleted, but that's OK - this is a singleton and</span>
<a name="l00077"></a>00077 <span class="comment">// so the 'leak' is really just a constant amount of memory that</span>
<a name="l00078"></a>00078 <span class="comment">// gets used.</span>
<a name="l00079"></a>00079 d_signal_handlers[i] = 0;
<a name="l00080"></a>00080 d_old_handlers[i] = 0;
<a name="l00081"></a>00081 }
<a name="l00082"></a>00082
<a name="l00083"></a>00083 <span class="keyword">delete</span> SignalHandler::d_instance;
<a name="l00084"></a>00084 SignalHandler::d_instance = 0;
<a name="l00085"></a>00085 }
<a name="l00086"></a>00086 }
<a name="l00087"></a>00087
<a name="l00094"></a>00094 <span class="keywordtype">void</span>
<a name="l00095"></a>00095 SignalHandler::dispatcher(<span class="keywordtype">int</span> signum)
<a name="l00096"></a>00096 {
<a name="l00097"></a>00097 <span class="comment">// Perform a sanity check...</span>
<a name="l00098"></a>00098 <span class="keywordflow">if</span> (SignalHandler::d_signal_handlers[signum] != 0)
<a name="l00099"></a>00099 <span class="comment">// Dispatch the handler's hook method.</span>
<a name="l00100"></a>00100 SignalHandler::d_signal_handlers[signum]->handle_signal(signum);
<a name="l00101"></a>00101
<a name="l00102"></a>00102 <a class="code" href="namespacelibdap.html#aa9d529378270ad490952b2b3352935ed">Sigfunc</a> *old_handler = SignalHandler::d_old_handlers[signum];
<a name="l00103"></a>00103 <span class="keywordflow">if</span> (old_handler == SIG_IGN || old_handler == SIG_ERR)
<a name="l00104"></a>00104 <span class="keywordflow">return</span>;
<a name="l00105"></a>00105 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (old_handler == SIG_DFL) {
<a name="l00106"></a>00106 <span class="keywordflow">switch</span> (signum) {
<a name="l00107"></a>00107 <span class="preprocessor">#ifndef WIN32</span>
<a name="l00108"></a>00108 <span class="preprocessor"></span> <span class="keywordflow">case</span> SIGHUP:
<a name="l00109"></a>00109 <span class="keywordflow">case</span> SIGKILL:
<a name="l00110"></a>00110 <span class="keywordflow">case</span> SIGUSR1:
<a name="l00111"></a>00111 <span class="keywordflow">case</span> SIGUSR2:
<a name="l00112"></a>00112 <span class="keywordflow">case</span> SIGPIPE:
<a name="l00113"></a>00113 <span class="keywordflow">case</span> SIGALRM:
<a name="l00114"></a>00114 <span class="preprocessor">#endif</span>
<a name="l00115"></a>00115 <span class="preprocessor"></span> <span class="keywordflow">case</span> SIGINT:
<a name="l00116"></a>00116 <span class="keywordflow">case</span> SIGTERM: _exit(EXIT_FAILURE);
<a name="l00117"></a>00117
<a name="l00118"></a>00118 <span class="comment">// register_handler() should never allow any fiddling with</span>
<a name="l00119"></a>00119 <span class="comment">// signals other than those listed above.</span>
<a name="l00120"></a>00120 <span class="keywordflow">default</span>: abort();
<a name="l00121"></a>00121 }
<a name="l00122"></a>00122 }
<a name="l00123"></a>00123 <span class="keywordflow">else</span>
<a name="l00124"></a>00124 old_handler(signum);
<a name="l00125"></a>00125 }
<a name="l00126"></a>00126
<a name="l00128"></a>00128 SignalHandler*
<a name="l00129"></a><a class="code" href="classlibdap_1_1SignalHandler.html#a930f996d318cadd5f0875da0784cb32a">00129</a> <a class="code" href="classlibdap_1_1SignalHandler.html#a930f996d318cadd5f0875da0784cb32a">SignalHandler::instance</a>()
<a name="l00130"></a>00130 {
<a name="l00131"></a>00131 pthread_once(&instance_control, initialize_instance);
<a name="l00132"></a>00132
<a name="l00133"></a>00133 <span class="keywordflow">return</span> d_instance;
<a name="l00134"></a>00134 }
<a name="l00135"></a>00135
<a name="l00148"></a>00148 <a class="code" href="classlibdap_1_1EventHandler.html">EventHandler</a> *
<a name="l00149"></a><a class="code" href="classlibdap_1_1SignalHandler.html#a1188177d392bdc1db6cf4450132c6d9f">00149</a> <a class="code" href="classlibdap_1_1SignalHandler.html#a1188177d392bdc1db6cf4450132c6d9f">SignalHandler::register_handler</a>(<span class="keywordtype">int</span> signum, <a class="code" href="classlibdap_1_1EventHandler.html">EventHandler</a> *eh, <span class="keywordtype">bool</span> <span class="keyword">override</span>)
<a name="l00150"></a>00150 {
<a name="l00151"></a>00151 <span class="comment">// Check first for improper use.</span>
<a name="l00152"></a>00152 <span class="keywordflow">switch</span> (signum) {
<a name="l00153"></a>00153 <span class="preprocessor">#ifndef WIN32</span>
<a name="l00154"></a>00154 <span class="preprocessor"></span> <span class="keywordflow">case</span> SIGHUP:
<a name="l00155"></a>00155 <span class="keywordflow">case</span> SIGKILL:
<a name="l00156"></a>00156 <span class="keywordflow">case</span> SIGUSR1:
<a name="l00157"></a>00157 <span class="keywordflow">case</span> SIGUSR2:
<a name="l00158"></a>00158 <span class="keywordflow">case</span> SIGPIPE:
<a name="l00159"></a>00159 <span class="keywordflow">case</span> SIGALRM:
<a name="l00160"></a>00160 <span class="preprocessor">#endif</span>
<a name="l00161"></a>00161 <span class="preprocessor"></span> <span class="keywordflow">case</span> SIGINT:
<a name="l00162"></a>00162 <span class="keywordflow">case</span> SIGTERM: <span class="keywordflow">break</span>;
<a name="l00163"></a>00163
<a name="l00164"></a>00164 <span class="keywordflow">default</span>: <span class="keywordflow">throw</span> <a class="code" href="classlibdap_1_1InternalErr.html" title="A class for software fault reporting.">InternalErr</a>(__FILE__, __LINE__,
<a name="l00165"></a>00165 <span class="keywordtype">string</span>(<span class="stringliteral">"Call to register_handler with unsupported signal ("</span>)
<a name="l00166"></a>00166 + <a class="code" href="namespacelibdap.html#a317edea830aab50d2137a5bd313cc86a">long_to_string</a>(signum) + <span class="keywordtype">string</span>(<span class="stringliteral">")."</span>));
<a name="l00167"></a>00167 }
<a name="l00168"></a>00168
<a name="l00169"></a>00169 <span class="comment">// Save the old EventHandler</span>
<a name="l00170"></a>00170 <a class="code" href="classlibdap_1_1EventHandler.html">EventHandler</a> *old_eh = SignalHandler::d_signal_handlers[signum];
<a name="l00171"></a>00171
<a name="l00172"></a>00172 SignalHandler::d_signal_handlers[signum] = eh;
<a name="l00173"></a>00173
<a name="l00174"></a>00174 <span class="comment">// Register the dispatcher to handle this signal. See Stevens, Advanced</span>
<a name="l00175"></a>00175 <span class="comment">// Programming in the UNIX Environment, p.298.</span>
<a name="l00176"></a>00176 <span class="preprocessor">#ifndef WIN32</span>
<a name="l00177"></a>00177 <span class="preprocessor"></span> <span class="keyword">struct </span>sigaction sa;
<a name="l00178"></a>00178 sa.sa_handler = dispatcher;
<a name="l00179"></a>00179 sigemptyset(&sa.sa_mask);
<a name="l00180"></a>00180 sa.sa_flags = 0;
<a name="l00181"></a>00181
<a name="l00182"></a>00182 <span class="comment">// Try to suppress restarting system calls if we're handling an alarm.</span>
<a name="l00183"></a>00183 <span class="comment">// This lets alarms block I/O calls that would normally restart. 07/18/03</span>
<a name="l00184"></a>00184 <span class="comment">// jhrg</span>
<a name="l00185"></a>00185 <span class="keywordflow">if</span> (signum == SIGALRM) {
<a name="l00186"></a>00186 <span class="preprocessor">#ifdef SA_INTERUPT</span>
<a name="l00187"></a>00187 <span class="preprocessor"></span> sa.sa_flags |= SA_INTERUPT;
<a name="l00188"></a>00188 <span class="preprocessor">#endif</span>
<a name="l00189"></a>00189 <span class="preprocessor"></span> }
<a name="l00190"></a>00190 <span class="keywordflow">else</span> {
<a name="l00191"></a>00191 <span class="preprocessor">#ifdef SA_RESTART</span>
<a name="l00192"></a>00192 <span class="preprocessor"></span> sa.sa_flags |= SA_RESTART;
<a name="l00193"></a>00193 <span class="preprocessor">#endif</span>
<a name="l00194"></a>00194 <span class="preprocessor"></span> }
<a name="l00195"></a>00195
<a name="l00196"></a>00196 <span class="keyword">struct </span>sigaction osa; <span class="comment">// extract the old handler/action</span>
<a name="l00197"></a>00197
<a name="l00198"></a>00198 <span class="keywordflow">if</span> (sigaction(signum, &sa, &osa) < 0)
<a name="l00199"></a>00199 <span class="keywordflow">throw</span> <a class="code" href="classlibdap_1_1InternalErr.html" title="A class for software fault reporting.">InternalErr</a>(__FILE__, __LINE__, <span class="stringliteral">"Could not register a signal handler."</span>);
<a name="l00200"></a>00200
<a name="l00201"></a>00201 <span class="comment">// Take care of the case where this interface is used to register a</span>
<a name="l00202"></a>00202 <span class="comment">// handler more than once. We want to make sure that the dispatcher is</span>
<a name="l00203"></a>00203 <span class="comment">// not installed as the 'old handler' because that results in an infinite</span>
<a name="l00204"></a>00204 <span class="comment">// loop. 02/10/04 jhrg</span>
<a name="l00205"></a>00205 <span class="keywordflow">if</span> (<span class="keyword">override</span>)
<a name="l00206"></a>00206 SignalHandler::d_old_handlers[signum] = SIG_IGN;
<a name="l00207"></a>00207 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (osa.sa_handler != dispatcher)
<a name="l00208"></a>00208 SignalHandler::d_old_handlers[signum] = osa.sa_handler;
<a name="l00209"></a>00209 <span class="preprocessor">#endif</span>
<a name="l00210"></a>00210 <span class="preprocessor"></span>
<a name="l00211"></a>00211 <span class="keywordflow">return</span> old_eh;
<a name="l00212"></a>00212 }
<a name="l00213"></a>00213
<a name="l00217"></a>00217 <a class="code" href="classlibdap_1_1EventHandler.html">EventHandler</a> *
<a name="l00218"></a><a class="code" href="classlibdap_1_1SignalHandler.html#ac9a9ddb318ad6b372604a4c8d58481de">00218</a> <a class="code" href="classlibdap_1_1SignalHandler.html#ac9a9ddb318ad6b372604a4c8d58481de">SignalHandler::remove_handler</a>(<span class="keywordtype">int</span> signum)
<a name="l00219"></a>00219 {
<a name="l00220"></a>00220 <a class="code" href="classlibdap_1_1EventHandler.html">EventHandler</a> *old_eh = SignalHandler::d_signal_handlers[signum];
<a name="l00221"></a>00221
<a name="l00222"></a>00222 SignalHandler::d_signal_handlers[signum] = 0;
<a name="l00223"></a>00223
<a name="l00224"></a>00224 <span class="keywordflow">return</span> old_eh;
<a name="l00225"></a>00225 }
<a name="l00226"></a>00226
<a name="l00227"></a>00227 } <span class="comment">// namespace libdap</span>
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