001 package javax.realtime;
002
003 import java.util.HashMap;
004
005 /** Use instances of <code>AsyncEvent</code> to handle POSIX signals. Usage:
006 * <p>
007 * <code>
008 * POSIXSignalHandler.addHandler(SIGINT, intHandler);
009 * </code>
010 * <p>
011 * This class is required to be implemented only if the underlying
012 * system supports POSIX signals.
013 */
014 public final class POSIXSignalHandler {
015
016 // Spec says all these fields should be final, but I don't see how
017 // to make them final and to guarantee the "platform independence".
018 // So I just "un-final-ed" them, and I'll set them at the runtime,
019 // using JNI.
020
021 /** Used by abort, replace <code>SIBIOT</code> in the future. */
022 public static /*final*/ int SIGABRT;
023 /** Alarm clock. */
024 public static /*final*/ int SIGALRM;
025 /** Bus error. */
026 public static /*final*/ int SIGBUS;
027 /** Thread cancellation signal used by <code>libthread</code>. */
028 public static /*final*/ int SIGCANCEL;
029 /** Child status change alis (POSIX). */
030 public static /*final*/ int SIGCHLD;
031 /** Child status change. */
032 public static /*final*/ int SIGCLD;
033 /** Stopped process has been continued. */
034 public static /*final*/ int SIGCONT;
035 /** EMT instructions. */
036 public static /*final*/ int SIGEMT;
037 /** Floaating point exception. */
038 public static /*final*/ int SIGFPE;
039 /** Special signal used by CPR. */
040 public static /*final*/ int SIGFREEZE;
041 /** Hangup. */
042 public static /*final*/ int SIGHUP;
043 /** Illegal instruction (not reset when caught). */
044 public static /*final*/ int SIGILL;
045 /** Interrupt (rubout). */
046 public static /*final*/ int SIGINT;
047 /** Socked I/O possible (<code>SIGPOLL alias). */
048 public static /*final*/ int SIGIO;
049 /** IOT instruction. */
050 public static /*final*/ int SIGIOT;
051 /** Kill (cannot be caught or ignored). */
052 public static /*final*/ int SIGKILL;
053 /** Resource lost (e.g., record-lock lost). */
054 public static /*final*/ int SIGLOST;
055 /** Special signal used by thread library. */
056 public static /*final*/ int SIGLWP;
057 /** Write on a pipe with no one to read it. */
058 public static /*final*/ int SIGPIPE;
059 /** Pollable event occured. */
060 public static /*final*/ int SIGPOLL;
061 /** Profiling timer expired. */
062 public static /*final*/ int SIGPROF;
063 /** Power-fail restart. */
064 public static /*final*/ int SIGPWR;
065 /** Quit (ASCII FS). */
066 public static /*final*/ int SIGQUIT;
067 /** Segmentation violation. */
068 public static /*final*/ int SIGSEGV;
069 /** Stop (cannot be caught or ignored). */
070 public static /*final*/ int SIGSTOP;
071 /** Bad argument to system call. */
072 public static /*final*/ int SIGSYS;
073 /** Software termination signal from kill. */
074 public static /*final*/ int SIGTERM;
075 /** Special signal used by CPR. */
076 public static /*final*/ int SIGTHAW;
077 /** Trace trap (not reset when caught). */
078 public static /*final*/ int SIGTRAP;
079 /** User stop requested from tty. */
080 public static /*final*/ int SIGTSTP;
081 /** Background tty read attempted. */
082 public static /*final*/ int SIGTTIN;
083 /** Background tty write attempted. */
084 public static /*final*/ int SIGTTOU;
085 /** Urgent socket condition. */
086 public static /*final*/ int SIGURG;
087 /** User defined signal = 1. */
088 public static /*final*/ int SIGUSR1;
089 /** User defined signal = 2. */
090 public static /*final*/ int SIGUSR2;
091 /** Virtual timer expired. */
092 public static /*final*/ int SIGVTALRM;
093 /** Process's lwps are blocked. */
094 public static /*final*/ int SIGWAITING;
095 /** Window size change. */
096 public static /*final*/ int SIGWINCH;
097 /** Exceeded cpu limit. */
098 public static /*final*/ int SIGXCPU;
099 /** Exceeded file size limit. */
100 public static /*final*/ int SIGXFSZ;
101
102 // I don't know what are the codes of all these signals, but I guess they are all <50.
103 // If you know that any of these signals has a code >50, just change MAX_SIG.
104 private static final int MAX_SIG = 50;
105 private static AsyncEvent[] signalsHandlersList = new AsyncEvent[MAX_SIG];
106
107 public POSIXSignalHandler() {
108 setSignals();
109 for (int i = 0; i < MAX_SIG; i++) signalsHandlersList[i] = new AsyncEvent();
110 }
111
112 /** Add the given <code>AsyncEventHandler</code> to the list of
113 * handlers of the <code>AsyncEvent</code> of the given signal.
114 *
115 * @param signal One of the POSIX signals from <code>this</code> (e.g.,
116 * <code>this.SIGLOST</code>). If the value given to
117 * <code>signal</code> is not one of the POSIX signals
118 * then a <code>java.lang.IllegalArgumentException</code>
119 * will be thrown.
120 * @param handler An <code>AsyncEventHandler</code> which will be
121 * scheduled when the given signal occurs.
122 */
123 public static void addHandler(int signal, AsyncEventHandler handler) {
124 signalsHandlersList[signal].addHandler(handler);
125 }
126
127 /** Remove the given <code>AsyncEventHandler</code> to the list
128 * of handlers of the <code>AsyncEvent</code> of the given signal.
129 *
130 * @param signal One of the POSIX signals from <code>this</code> (e.g.,
131 * <code>this.SIGLOST</code>). If the value given to
132 * <code>signal</code> is not one of the POSIX signals
133 * then a <code>java.lang.IllegalArgumentException</code>
134 * will be thrown.
135 * @param handler An <code>AsyncEventHandler</code> which will be
136 * scheduled when the given signal occurs.
137 */
138 public static void removeHandler(int signal, AsyncEventHandler handler) {
139 signalsHandlersList[signal].removeHandler(handler);
140 }
141
142 /** Set the given <code>AsyncEventHandler</code> as the handler
143 * of the <code>AsyncEvent</code> of the given signal.
144 * @param signal One of the POSIX signals from <code>this</code> (e.g.,
145 * <code>this.SIGLOST</code>). If the value given to
146 * <code>signal</code> is not one of the POSIX signals
147 * then a <code>java.lang.IllegalArgumentException</code>
148 * will be thrown.
149 * @param handler An <code>AsyncEventHandler</code> which will be
150 * scheduled when the given signal occurs. If
151 * <code>handler</code> is null then no handler will be
152 * associated with <code>this</code> (i.e., remove all handlers).
153 */
154 public static void setHandler(int signal, AsyncEventHandler handler) {
155 signalsHandlersList[signal].setHandler(handler);
156 }
157
158 /** Assigns machine-dependent values to all <code>SIGxxxx</code> constants. */
159 private native void setSignals();
160 }