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1   /*
2    * Copyright (c) 2001, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.
8    *
9    * This code is distributed in the hope that it will be useful, but WITHOUT
10   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12   * version 2 for more details (a copy is included in the LICENSE file that
13   * accompanied this code).
14   *
15   * You should have received a copy of the GNU General Public License version
16   * 2 along with this work; if not, write to the Free Software Foundation,
17   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18   *
19   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20   * or visit www.oracle.com if you need additional information or have any
21   * questions.
22   *
23   */
24  
25  package sun.jvm.hotspot.debugger.cdbg;
26  
27  import sun.jvm.hotspot.debugger.*;
28  
29  /** <P> A highly experimental interface for process control and debug
30      events. May not be sufficiently portable; for this reason it has
31      been factored out from the CDebugger interface and support for it
32      is optional. </P>
33  
34      <P> The ProcessControl interface defines a process control and
35      event model for debugging. When a process is attached to by the
36      base Debugger, all threads in the target process are suspended.
37      The ProcessControl interface allows resumption and re-suspension
38      of the threads in the target process, setting of breakpoints, and
39      reception of debugging events (breakpoint hit, signal received,
40      etc.). </P>
41  
42      <P> Debugging events are generated one at a time by the target
43      process. They must be queued up by the underlying debugging
44      mechanism so that an attempt to send a second debugging event
45      blocks until the first has been serviced with a call to
46      debugEventResume. </P> */
47  
48  public interface ProcessControl {
49    /** Suspends all threads in the target process. A process is already
50        suspended when attached to by {@link
51        sun.jvm.hotspot.debugger.Debugger.attach(int)}. The application
52        should check for the presence of a debug event via
53        debugEventPoll() upon re-suspending the target process (if one
54        is not yet known to be present.)
55  
56        @throw DebuggerException if the process is already suspended or
57        if the suspension failed for some other reason. */
58    public void suspend() throws DebuggerException;
59  
60    /** Resumes all threads in the target process.
61  
62        @throw DebuggerException if the process is not suspended or if
63        the resumption failed for some other reason. */
64    public void resume() throws DebuggerException;
65  
66    /** Indicates whether the target process is suspended. */
67    public boolean isSuspended() throws DebuggerException;
68  
69    /** Sets a breakpoint at the given address. The target process must
70        be suspended in order to set a breakpoint.
71  
72        @throw DebuggerException if the breakpoint could not be set for
73        some reason, including that a breakpoint is already set at that
74        address or that the underlying debugging mechanism does not
75        support that many breakpoints. */
76    public void setBreakpoint(Address addr)
77      throws UnmappedAddressException, DebuggerException;
78  
79    /** Clears a breakpoint at the given address. The target process
80        must be suspended in order to clear a breakpoint.
81  
82        @throw DebuggerException if the breakpoint could not be cleared
83        for some reason, including that there was no breakpoint at that
84        address. */
85    public void clearBreakpoint(Address addr) throws DebuggerException;
86  
87    /** Indicates whether a breakpoint is set at the given address. */
88    public boolean isBreakpointSet(Address addr) throws DebuggerException;
89  
90    /** Polls for the presence of a debug event. Does not wait for one
91        to be generated; returns null if none was pending. The target
92        process does not need to be suspended. Returns the same
93        DebugEvent object until the debug event is handled via
94        debugEventContinue. Typically the application will suspend the
95        target process upon reception of a debug event but before
96        handling it via a call to debugEventContinue. This ensures that
97        the state of the thread which generated the debug event is
98        precisely what it was when the event was generated.
99  
100       @return The pending debug event, or null if none pending. */
101   public DebugEvent debugEventPoll() throws DebuggerException;
102 
103   /** Informs the target process to resume past this debug event. The
104       target process does not need to be suspended. Breakpoint debug
105       events must be handled transparently by the implementation to
106       re-execute the instruction and replace the breakpoint. (Ideally
107       they should be replaced in such a way that there is no race
108       condition between the re-execution and the re-insertion of the
109       breakpoint.) All other kinds of exceptions or signals are passed
110       on to the target process.
111 
112       @throw DebuggerException if no debug event is pending. */
113   public void debugEventContinue()
114     throws DebuggerException;
115 }